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Mitochondrial Transplantation: A Unique Treatment Strategy
Abstract
Mitochondrial transplantation refers to the process of introducing isolated mitochondria into a damaged area of the heart or other organs. In the past decade, this technique has been continuously updated as the fundamental research on the repair of damaged cells or tissues. Particularly, in the field of heart protection from ischemia-reperfusion injury, the MT therapy has been developed to the clinical trial stage. Generally speaking, the goal of therapeutic intervention is to replace damaged mitochondria or increase the transfer of mitochondria between cells so as to improve mitochondrial dysfunction. In this review, we summarized the studies on mitochondrial transplantation conducted at different time nodes and outlined a range of different methods for delivering mitochondria into the target site. Finally, we described the applications of mitochondrial transplantation in different diseases, and discussed the clinical studies of human mitochondrial transplantation currently in progress as well as the problems that need to be overcome. We hope to provide new ideas for the treatment of mitochondrial defects related diseases.
... Although this functional change occurs during ischemia, an increase is also observed during restoration of myocardial blood flow and oxygen distribution to the tissue. It is known that this condition shortens the contractions and lifetimes of myocardium (1). ...
... Application of Mitochondrial Transplantation for Various Diseases with related sources of m itochondriai transfer models, results and references(1) ...
Hücre enerji eldesinde üstlendikleri eşsiz rolleri ile mitokondri yıllardır devam eden araştırmalar ile incelenmeye devam etmektedir. Mitokondriyal transfer hasarlanmış dokuya izole edilmiş olan mitokondrinin transfer edilme süreci olarak özetlenebilir. Bu sayede kalp hasarı olan doku gibi mitokondrial fonksiyonları bozulmuş bölgede mitokondrial disfonksiyon durmunun düzeltilmesi amaçlanmaktadır. Bu konu ile ilgili özellikle kalp dokusunda birçok çalışma olmakla beraber uygulanın miyokardial iskemi, reperfüzyon hasarı gibi süreçlerde koruyucu etkinliği araştırılmaya devam etmektedir. İzole edilen mitokondrin hasarlı dokuya aktarılmasında farklı prosedürler bulunmakla birlikte, birçok çalışmada uygulama ile ilgili olumlu sonuçlar bildirlmektedir. Derlemede literatürde bu alanda yapılmış olan çalışmalar incelenmekle birlikte konuya geniş bir penceren bakılması hedeflenmiştir.
... Nowadays, researchers have been investigating the use of mitochondrial transplantation as a new treatment approach for mitochondrial disorders. In this approach, healthy exogenous mitochondria are transferred to damaged cells (48)(49)(50). ...
Background: Doxorubicin (DOX) is used in the treatment of various cancers and has good effectiveness. However, its therapeutic use is limited due to its effects on various organs and healthy cells. Doxorubicin can affect the kidneys and cause toxicity. Evidence shows that DOX induces nephrotoxicity through oxidative stress. Objectives: In this research, we examined the effect of mitochondrial transplantation on improving mitochondrial and cellular toxicity caused by DOX on renal proximal tubular cells (RPTCs). Methods: The research measured 7 toxicity parameters, including cell lysis, reactive oxygen species (ROS) formation, mitochondrial membrane potential (MMP) decline, GSH and GSSG content, lipid peroxidation (LPO), adenosine triphosphate (ATP) content, and Caspase-3 activity (the final mediator of apoptosis). Active fresh mitochondria were prepared from Wistar rat kidney. Results: The findings indicated that DOX caused cytotoxicity in RPTCs. Additionally, DOX induced oxidative stress by increasing the level of reactive oxygen species, reducing glutathione content, and elevating lipid peroxidation. Moreover, it led to damage to the mitochondrial membrane, increased caspase-3 activity, and decreased ATP content. Mitochondrial transplantation, as a new therapeutic approach, reduced oxidative stress, mitochondrial membrane damage, and apoptosis caused by DOX in RPTCs. Furthermore, this therapeutic approach increased the ATP content in RPTCs. Conclusions: Our study suggests that this therapeutic approach could be helpful in the treatment of drug-induced nephrotoxicity.
... Los estudios han mostrado que las mitocondrias de una célula sana se transfieren a una célula que está bajo condiciones no favorables, como en un proceso cancerígeno o, como se mencionó, en estrés oxidante (Chen, Zhong, Wang & Chen, 2021;Zhou et al., 2022;Hosseinian, Ali Pour & Kheradvar, 2022). ...
Durante años se consideró que la función más importante de las mitocondrias era la de proveer a la célula de energía en forma de ATP o incluso, fungir como amortiguadores de la concentración del calcio citosólico. Sin embargo, se ha demostrado que las mitocondrias tienen más atributos al ser una parte medular de las cascadas de señalización, y de compartir funciones con las estructuras intra y extracelulares que permiten mantener la homeostasis y la función celular. Además, hay reportes que muestran que las células sanas pueden transferir a las mitocondrias por el torrente circulatorio o directamente a las células dañadas con el objetivo de brindarles protección y mejorar su función bioenergética en condiciones específicas. Los mecanismos de señalización para el reconocimiento de moléculas marcadoras son determinantes para establecer la transferencia de las mitocondrias entre células y a través de las estructuras vesiculares o de los túneles (TNT), entre otros sistemas. Actualmente, se han desarrollado estrategias para el aislamiento de las mitocondrias, las cuales, a su vez, se inyectan en los tejidos permitiéndoles su recuperación funcional, a lo que se ha llamado la “medicina mitocondrial” o la “mitocuración”. Aunque estos hallazgos sugieren que las mitocondrias podrían ser un nuevo método de profilaxis para las enfermedades o trastornos metabólicos, es necesario considerar que la transferencia mitocondrial no es del todo una solución positiva en el tratamiento de algunos padecimientos.
Objectives
Exogenous mitochondria transplantation or mitotherapy can be used to swap out unhealthy mitochondria for functioning ones. Treatment of mitochondrial diseases using this approach may be beneficial.
Methods
In this study, we looked at the effect of transplanting newly isolated mitochondria on the toxicity that favipiravir (FAV) causes in renal proximal tubular cells (RPTCs). In this study, parameters such as lactate dehydrogenase (LDH) leakiness, reactive oxygen species (ROSs) production, damage to the lysosome membrane, reduced glutathione (GSH) content, extracellular oxidized glutathione (GSSG) content, GSH/GSSG ratio, ATP level, mitochondrial membrane potential (MMP) collapse, Bcl-2 content, and caspase-3 activity were used to assess the protective effects of mitochondrial transplantation against FAV-induced mitochondrial toxicity.
Key findings
The statistical analysis showed that the cytotoxicity, ROS production, MMP collapse, lysosomal damage, GSSG levels, and caspase-3 activity brought on by FAV in RPTCs were reduced by transplanting the healthy mitochondria. In addition, it led to an increase in ATP level, GSH content, Bcl-2 content, and GSH/GSSG ratio in RPTCs.
Conclusions
A recent study found that mitochondrial transplantation is a powerful therapeutic approach for treating nephrotoxicity brought on by xenobiotics.
Familial Parkinson disease (PD) is associated with rare genetic mutations, but the etiology in most patients with sporadic (s)PD is largely unknown, and the basis for its progression to dementia (sPDD) is poorly characterized. We have identified that loss of IFNβ or IFNAR1, the receptor for IFNα/β, causes pathological and behavioral changes resembling PDD, prompting us to hypothesize that dysregulated genes in IFNβ-IFNAR signaling pathway predispose one to sPD. By transcriptomic analysis, we found defective neuronal IFNβ-IFNAR signaling, including particularly elevated PIAS2 associated with sPDD. With meta-analysis of GWASs, we identified sequence variants in IFNβ-IFNAR-related genes in sPD patients. Furthermore, sPDD patients expressed higher levels of PIAS2 mRNA and protein in neurons. To determine its function in brain, we overexpressed PIAS2 under a neuronal promoter, alone or with human α-synuclein, in the brains of mice, which caused motor and cognitive impairments and correlated with intraneuronal phosphorylated (p)α-synuclein accumulation and dopaminergic neuron loss. Ectopic expression of neuronal PIAS2 blocked mitophagy, increased the accumulation of senescent mitochondrial and oxidative stress, as evidenced by excessive oxDJ1 and 8OHdG, by inactivating ERK1/2-P53 signaling. Conversely, PIAS2 knockdown rescued the clinicopathological manifestations of PDD in Ifnb–/– mice on restoring mitochondrial homeostasis, oxidative stress, and pERK1/2-pP53 signaling. The regulation of JAK-STAT2-PIAS2 signaling was crucial for neurite outgrowth and neuronal survival and excitability and thus might prevent cognitive impairments. Our findings provide insights into the progression of sPD and dementia and have implications for new therapeutic approaches.
Mitochondria are organelles with vital functions in almost all eukaryotic cells. Often described as the cellular ‘powerhouses’ due to their essential role in aerobic oxidative phosphorylation, mitochondria perform many other essential functions beyond energy production. As signaling organelles, mitochondria communicate with the nucleus and other organelles to help maintain cellular homeostasis, allow cellular adaptation to diverse stresses, and help steer cell fate decisions during development. Mitochondria have taken center stage in the research of normal and pathological processes, including normal tissue homeostasis and metabolism, neurodegeneration, immunity and infectious diseases. The central role that mitochondria assume within cells is evidenced by the broad impact of mitochondrial diseases, caused by defects in either mitochondrial or nuclear genes encoding for mitochondrial proteins, on different organ systems. In this Review, we will provide the reader with a foundation of the mitochondrial ‘hardware’, the mitochondrion itself, with its specific dynamics, quality control mechanisms and cross-organelle communication, including its roles as a driver of an innate immune response, all with a focus on development, disease and aging. We will further discuss how mitochondrial DNA is inherited, how its mutation affects cell and organismal fitness, and current therapeutic approaches for mitochondrial diseases in both model organisms and humans.
Today mitochondria are considered much more than a energy plant in cells. Mitochondrial transplantation therapy has been an active research area for treating mitochondria-associated diseases from animal studies to clinical trials. However, the specific mechanism involved in the anti-tumor activity of healthy mitochondria remain to be characterized. Here we investigate the signal mechanism and gender difference of mitochondrial transplantation therapy against malignant melanoma. In the study, we administrated intact mitochondria extracted from mouse livers respectively to the mice bearing malignantly subcutaneous and metastatic melanoma, and identified the signal mechanism responsible for the mitochondrial treatment through transcriptomic analysis. Meanwhile, the efficiency of female mitochondria and male mitochondria was compared in the cultured melanoma cells and transplanted melanoma in mice. The results suggested that the mitochondria significantly inhibited the tumor cell proliferation in vitro through cell cycle arrest and induction of cell apoptosis. In the melanoma-bearing mice, the mitochondria retard the tumor growth and lung migration, and the transcriptomic analysis indicated that general chromosome silencing was strongly associated with the mitochondria against melanoma after the mitochondrial transplantation on the metastasis melanoma. Moreover, the anti-tumor activity of mitochondria from female animals was more efficient in comparison to the males, and the female mitochondria could probably induce more persuasive mitochondria-nuclear communication than the mitochondria from male mice. The study identifies the anti-tumor mechanism of the mitochondrial transplantation therapy, and provides a novel insight into the effect of mitochondria from different gender. © 2021, Ivyspring International Publisher. All rights reserved.
Background
Sepsis has a high mortality rate, but no specific drug has been proven effective, prompting the development of new drugs. Immunologically, sepsis can involve hyperinflammation, immune paralysis, or both, which might pose challenges during drug development. Recently, mitochondrial transplantation has emerged as a treatment modality for various diseases involving mitochondrial dysfunction, but it has never been tested for sepsis.
Methods
We isolated mitochondria from L6 muscle cells and umbilical cord mesenchymal stem cells and tested the quality of the isolated mitochondria. We conducted both in vivo and in vitro sepsis studies. We investigated the effects of intravenous mitochondrial transplantation on cecal slurry model in rats in terms of survival rate, bacterial clearance rate, and the immune response. Furthermore, we observed the effects of mitochondrial transplantation on the immune reaction regarding both hyperinflammation and immune paralysis. To do this, we studied early- and late-phase cytokine production in spleens from cecal slurry model in rats. We also used a lipopolysaccharide (LPS)-stimulated human PBMC monocyte model to confirm the immunological effects of mitochondrial transplantation. Apoptosis and the intrinsic apoptotic pathway were investigated in septic spleens.
Results
Mitochondrial transplantation improved survival and bacterial clearance. It also mitigated mitochondrial dysfunction and apoptosis in septic spleens and attenuated both hyperinflammation and immune paralysis in the spleens of cecal slurry model in rats. This effect was confirmed with an LPS-stimulated human PBMC study.
Conclusions
In rat polymicrobial cecal slurry model, the outcome is improved by mitochondrial transplantation, which might have an immunomodulatory effect.
Mitochondrial transplantation therapy is an innovative strategy for the treatment of mitochondrial dysfunction. The approach has been reported to be useful in the treatment of cardiac ischemic reperfusion injuries in human clinical trials and has also been shown to be useful in animal studies as a method for treating mitochondrial dysfunction in various tissues, including the heart, liver, lungs, and brain. On the other hand, there is no methodology for using preserved mitochondria. Research into the pharmaceutical formulation of mitochondria to promote mitochondrial transplantation therapy as the next step in treating many patients is urgently needed. In this review, we overview previous studies on the therapeutic effects of mitochondrial transplantation. We also discuss studies related to immune responses that occur during mitochondrial transplantation and methods for preserving mitochondria, which are key to their stability as medicines. Finally, we describe research related to mitochondrial targeting drug delivery systems (DDS) and discuss future perspectives of mitochondrial transplantation.
Background:
Mitochondrial dysfunction is related to brain ischemic injury and neural cell death. However, little is known about the association between mitochondrial dysfunction of cerebrospinal fluid (CSF) and delayed cerebral ischemia (DCI) following subarachnoid hemorrhage (SAH). The objective of this study was to investigate whether extracellular CSF mitochondria might serve as a potential biomarker for DCI.
Methods:
CSF samples were serially collected at 1, 3, and 5 days following SAH in 33 patients (DCI, n = 12; and non-DCI, n = 21) who underwent coil embolization. To monitor mitochondrial membrane potentials, JC-1 dye was used. The ratio (red/green) of JC-1 was considered as an indicator of intact mitochondrial membrane potential. Flow cytometry was done to analyze extracellular mitochondria particles and their possible cellular origins.
Results:
DCI patients had lower JC-1 red/green ratios than non-DCI patients at 1 day (3.35 [3.20-3.75] vs. 3.70 [3.40-3.95] in non-DCI) and 3 days (4.65 [4.45-5.00] vs. 5.10 [4.65-5.30] in non-DCI) after SAH. At 5 days after SAH, JC-1 red/green ratio was significantly lower in DCI than that in non-DCI (3.05 [2.90-3.35] vs. 4.20 [4.10-4.50]; p < 0.01) patients. DCI patients had a higher percentage of vWF-positive mitochondria (40.10% [38.25%-44.90%] vs. 30.20% [25.70%-36.68%]) and a lower percentage of GLAST-positive mitochondria particles (26.85% [17.10%-30.00%] vs. 31.60% [26.70%-35.00%]) than non-DCI patients. However, there was no significant difference in CD45-positive (p = 0.369) or CD41/61-positive mitochondrial particles (p = 0.155) between the two groups of patients.
Conclusions:
Mitochondrial membrane potential could be a marker of DCI. JC-1 ratios seemed to be able to predict future DCI onset. Further studies are needed to determine detailed mechanisms of extracellular mitochondria-mediated cell-to-cell signals in DCI.
Objectives:
Type 2 diabetes causes mitochondrial dysfunction, which increases myocardial susceptibility to ischaemia-reperfusion injury. We investigated the efficacy of transplantation of mitochondria isolated from diabetic or non-diabetic donors in providing cardioprotection from warm global ischaemia and reperfusion in the diabetic rat heart.
Methods:
Ex vivo perfused hearts from Zucker diabetic fatty (ZDF fa/fa) rats (n = 6 per group) were subjected to 30 min of warm global ischaemia and 120 min reperfusion. Immediately prior to reperfusion, vehicle alone (VEH) or vehicle containing mitochondria isolated from either ZDF (MTZDF) or non-diabetic Zucker lean (ZL +/?) (MTZL) skeletal muscle were delivered to the coronary arteries via the aortic cannula.
Results:
Following 30-min global ischaemia and 120-min reperfusion, left ventricular developed pressure was significantly increased in MTZDF and MTZL groups compared to VEH group (MTZDF: 92.8 ± 5.2 mmHg vs MTZL: 110.7 ± 2.4 mmHg vs VEH: 44.3 ± 5.9 mmHg; P < 0.01 each); and left ventricular end-diastolic pressure was significantly decreased (MTZDF 12.1 ± 1.3 mmHg vs MTZL 8.6 ± 0.8 mmHg vs VEH: 18.6 ± 1.5 mmHg; P = 0.016 for MTZDF vs VEH and P < 0.01 for MTZL vs VEH). Total tissue ATP content was significantly increased in both MT groups compared to VEH group (MTZDF: 18.9 ± 1.5 mmol/mg protein/mg tissue vs MTZL: 28.1 ± 2.3 mmol/mg protein/mg tissue vs VEH: 13.1 ± 0.5 mmol/mg protein/mg tissue; P = 0.018 for MTZDF vs VEH and P < 0.01 for MTZL vs VEH). Infarct size was significantly decreased in the MT groups (MTZDF: 11.8 ± 0.7% vs MTZL: 9.9 ± 0.5% vs VEH: 52.0 ± 1.4%; P < 0.01 each).
Conclusions:
Mitochondrial transplantation significantly enhances post-ischaemic myocardial functional recovery and significantly decreases myocellular injury in the diabetic heart.
Objective:
Acute limb ischemia (ALI), the most challenging form of ischemia-reperfusion injury (IRI) in skeletal muscle tissue, leads to decreased skeletal muscle viability and limb function. Mitochondrial injury has been shown to play a key role in skeletal muscle IRI. In previous studies, we have demonstrated that mitochondrial transplantation (MT) is an efficacious therapeutic strategy to replace or to augment mitochondria damaged by IRI, allowing enhanced muscle viability and function in cardiac tissue. In this study, we investigated the efficacy of MT in a murine ALI model.
Methods:
C57BL/6J mice (male, 10-12 weeks) were used in a model of ALI. Ischemia was induced by applying a tourniquet on the left hindlimb. After 2 hours of ischemia, the tourniquet was released, and reperfusion of the hindlimb was re-established; either vehicle alone (n = 15) or vehicle containing mitochondria (n = 33) was injected directly into all the muscles of the hindlimb. Mitochondria were delivered at concentrations of 1 × 106 to 1 × 109 per gram wet weight to each muscle, and the animals were allowed to recover. Sham mice received no ischemia or injections but were anesthetized for 2 hours and allowed to recover. After 24 hours of recovery, limb function was assessed by DigiGait (Mouse Specifics Inc, Boston, Mass), and animals were euthanized; the gastrocnemius, soleus, and vastus medialis muscles were collected for analysis.
Results:
After 24 hours of hindlimb reperfusion, infarct size (percentage of total mass) and apoptosis were significantly decreased (P < .001, each) in the gastrocnemius, soleus, and vastus medialis muscles in MT mice compared with vehicle mice for all mitochondrial concentrations (1 × 106 to 1 × 109 per gram wet weight). DigiGait analysis at 24 hours of reperfusion showed that percentage shared stance time was significantly increased (P < .001) and stance factor was significantly decreased (P = .001) in vehicle compared with MT and sham mice. No significant differences in percentage shared stance time (P = .160) or stance factor (P = .545) were observed between MT and sham mice.
Conclusions:
MT ameliorates skeletal muscle injury and enhances hindlimb function in the murine model of ALI.
Abstract Mitochondria take part in a network of cellular processes that regulate cell homeostasis. Defects in mitochondrial function are key pathophysiological changes during acute kidney injury (AKI). Mesenchymal stem cells (MSCs) have shown promising regenerative effects in experimental AKI models, but the specific mechanism is still unclear. Some studies have demonstrated that MSCs are able to target mitochondrial dysfunction during AKI. In this review, we summarize these articles, providing an integral and updated view of MSC therapy targeting mitochondrial dysfunction during AKI, which is aimed at promoting the therapeutic effect of MSCs in AKI patients.
Recent studies have demonstrated that bone marrow mesenchymal stem cells (BMSCs) protect the injured neurons of spinal cord injury (SCI) from apoptosis while the underlying mechanism of the protective effect of BMSCs remains unclear. In this study, we found the transfer of mitochondria from BMSCs to injured motor neurons and detected the functional improvement after transplanting.
Methods: Primary rat BMSCs were co-cultured with oxygen-glucose deprivation (OGD) injured VSC4.1 motor neurons or primary cortical neurons. FACS analysis was used to detect the transfer of mitochondria from BMSCs to neurons. The bioenergetics profiling of neurons was detected by Extracellular Flux Analysis. Cell viability and apoptosis were also measured. BMSCs and isolated mitochondria were transplanted into SCI rats. TdT-mediated dUTP nick end labelling staining was used to detect apoptotic neurons in the ventral horn. Immunohistochemistry and Western blotting were used to measure protein expression. Re-myelination was examined by transmission electron microscope. BBB scores were used to assess locomotor function.
Results: MitoTracker-Red labelled mitochondria of BMSCs could be transferred to the OGD injured neurons. The gap junction intercellular communication (GJIC) potentiator retinoid acid increased the quantity of mitochondria transfer from BMSCs to neurons, while GJIC inhibitor 18β glycyrrhetinic acid decreased mitochondria transfer. Internalization of mitochondria improved the bioenergetics profile, decreased apoptosis and promoted cell survival in post-OGD motor neurons. Furthermore, both transplantation of mitochondria and BMSCs to the injured spinal cord improved locomotor functional recovery in SCI rats.
Conclusions: To our knowledge, this is the first evidence that BMSCs protect against SCI through GJIC to transfer mitochondrial to the injured neurons. Our findings suggested a new therapy strategy of mitochondria transfer for the patients with SCI.
The innate immune system is a critical regulator of the adaptive immune responses that lead to allograft rejection. It is increasingly recognized that endogenous molecules released from tissue injury and cell death are potent activators of innate immunity. Mitochondria, ancestrally related to bacteria, possess an array of endogenous innate immune activating molecules. We have recently demonstrated that extracellular mitochondria are abundant in the circulation of deceased organ donors and that their presence correlates with early allograft dysfunction. Here we demonstrate the ability of mitochondria to activate ECs, the initial barrier between a solid‐organ allograft and its host. We find that mitochondria exposure leads to the upregulation of EC adhesion molecules and their production of inflammatory cytokines and chemokines. Additionally, mitochondrial exposure causes DCs to upregulate costimulatory molecules. Infusion of isolated mitochondria into heart donors lead to significant increase in allograft rejection in a murine heterotopic heart transplantation model. Finally, co‐incubation of human PBMCs with mitochondria treated ECs results in increased numbers of effector (IFN‐γ⁺, TNF‐α⁺) CD8⁺ T cells. These data indicate that circulating extracellular mitochondria in deceased organ donors may directly activate allograft ECs and promote graft rejection in transplant recipients.
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Background
The transfer of whole mitochondria that occurs during cell contact has been found to support cancer progression. However, the regulatory role of mitochondria alone is difficult to elucidate due to the complex microenvironment. Currently, mitochondrial transplantation is an available approach for restoring mitochondrial function in mitochondrial diseases but remains unclear in breast cancer. Herein, effects of mitochondrial transplantation via different approaches in breast cancer were investigated.
Methods
Whole mitochondria (approximately 10.5 μg/ml) were transported into MCF-7 breast cancer cells via passive uptake or Pep-1-mediated delivery. Fresh mitochondria isolated from homeoplasmic 143B osteosarcoma cybrids containing mitochondrial DNA (mtDNA) derived from health individuals (Mito) or mtDNA with the A8344G mutation (Mito⁸³⁴⁴) were conjugated with cell-penetrating peptide Pep-1 (P-Mito) or not conjugated prior to cell co-culture. Before isolation, mitochondria were stained with MitoTracker dye as the tracking label. After 3 days of treatment, cell viability, proliferation, oxidative stress, drug sensitivity to Doxorubicin/Paclitaxel and mitochondrial function were assessed.
Results
Compared with P-Mito, a small portion of Mito adhered to the cell membrane, and this was accompanied by a slightly lower fluorescent signal by foreign mitochondria in MCF-7 cells. Both transplantations induced cell apoptosis by increasing the nuclear translocation of apoptosis-inducing factor; inhibited cell growth and decreased oxidative stress in MCF-7 cells; and increased the cellular susceptibility of both the MCF-7 and MDA-MB-231 cell lines to Doxorubicin and Paclitaxel. Mitochondrial transplantation also consistently decreased Drp-1, which resulted in an enhancement of the tubular mitochondrial network, but a distinct machinery through the increase of parkin and mitochondrial fusion proteins was observed in the Mito and P-Mito groups, respectively. Furthermore, although there were no differences in energy metabolism after transplantation of normal mitochondria, metabolism was switched to the energetic and glycolytic phenotypes when the mitochondria were replaced with dysfunctional mitochondria, namely, Mito⁸³⁴⁴ and P-Mito⁸³⁴⁴, due to dramatically induced glycolysis and reduced mitochondrial respiration, respectively. Consequently, transplant-induced growth inhibition was abolished, and cell growth in the Mito⁸³⁴⁴ group was even higher than that in the control group.
Conclusion
This study reveals the antitumour potential of mitochondrial transplantation in breast cancer via distinct regulation of mitochondrial function.
Electronic supplementary material
The online version of this article (10.1186/s13046-019-1028-z) contains supplementary material, which is available to authorized users.
Mitochondrial dysfunction is a major and common mechanism in developing non-alcoholic fatty liver disease (NAFLD). Replacement of dysfunctional mitochondria by functional exogenous mitochondria may attenuate intrahepatic excessive lipid and recover hepatocyte function. However, no data shows that mitochondria can be systemically administrated to animals to date. Here we suggest that mitochondria isolated from hepatoma cells are used as a mitotherapy agent to treat mouse fatty liver induced by high-fat diets. When the mitochondria were intravenously injected into the mice, serum aminotransferase activity and cholesterol level decreased in a dose-dependent manner. Also, the mitotherapy reduced lipid accumulation and oxidation injury of the fatty liver mice, improved energy production, and consequently restored hepatocyte function. The mitotherapy strategy offers a new potential therapeutic approach for treating NAFLD.
Mitochondrial dysfunction has been implicated in a multitude of diseases and pathological conditions- the organelles that are essential for life can also be major players in contributing to cell death and disease. Because mitochondria are so well established in our existence, being present in all cell types except for red blood cells and having the responsibility of providing most of our energy needs for survival, then dysfunctional mitochondria can elicit devastating cellular pathologies that can be widespread across the entire organism. As such, the field of "mitochondrial medicine" is emerging in which disease states are being targeted therapeutically at the level of the mitochondrion, including specific antioxidants, bioenergetic substrate additions, and membrane uncoupling agents. New and compelling research investigating novel techniques for mitochondrial transplantation to replace damaged or dysfunctional mitochondria with exogenous healthy mitochondria has shown promising results, including tissue sparing accompanied by increased energy production and decreased oxidative damage. Various experimental techniques have been attempted and each has been challenged to accomplish successful transplantation. The purpose of this review is to present the history of mitochondrial transplantation, the different techniques used for both in vitro and in vivo delivery, along with caveats and pitfalls that have been discovered along the way. Results from such pioneering studies are promising and could be the next big wave of "mitochondrial medicine" once technical hurdles are overcome.
Objective:
To demonstrate the clinical efficacy of autologous mitochondrial transplantation in preparation for translation to human application using an in vivo swine model.
Methods:
A left mini-thoracotomy was performed on Yorkshire pigs. The pectoralis major was dissected, and skeletal muscle tissue was removed and used for the isolation of autologous mitochondria. The heart was subjected to regional ischemia (RI) by temporarily snaring the circumflex artery. After 24 minutes of RI, hearts received 8 × 0.1 mL injections of vehicle (vehicle-only group; n = 6) or vehicle containing mitochondria (mitochondria group; n = 6) into the area at risk (AAR), and the snare was released. The thoracotomy was closed, and the pigs were allowed to recover for 4 weeks.
Results:
Levels of creatine kinase-MB isoenzyme and cardiac troponin I were significantly increased (P = .006) in the vehicle-only group compared with the mitochondria group. Immune, inflammatory, and cytokine activation markers showed no significant difference between groups. There was no significant between-group difference in the AAR (P = .48), but infarct size was significantly greater in the vehicle group (P = .004). Echocardiography showed no significant differences in global function. Histochemistry and transmission electron microscopy revealed damaged heart tissue in the vehicle group that was not apparent in the mitochondria group. T2-weighted magnetic resonance imaging and histology demonstrated that the injected mitochondria were present for 4 weeks.
Conclusions:
Autologous mitochondrial transplantation provides a novel technique to significantly enhance myocardial cell viability following ischemia and reperfusion in the clinically relevant swine model.
Recent studies have demonstrated that mesenchymal stem cells (MSCs) can donate mitochondria to airway epithelial cells and rescue mitochondrial damage in lung injury. We sought to determine whether MSCs could donate mitochondria and protect against oxidative stress-induced mitochondrial dysfunction in the cornea. Co-culturing of MSCs and corneal epithelial cells (CECs) indicated that the efficiency of mitochondrial transfer from MSCs to CECs was enhanced by Rotenone (Rot)-induced oxidative stress. The efficient mitochondrial transfer was associated with increased formation of tunneling nanotubes (TNTs) between MSCs and CECs, tubular connections that allowed direct intercellular communication. Separation of MSCs and CECs by a transwell culture system revealed no mitochiondrial transfer from MSCs to CECs and mitochondrial function was impaired when CECs were exposed to Rot challenge. CECs with or without mitochondrial transfer from MSCs displayed a distinct survival capacity and mitochondrial oxygen consumption rate. Mechanistically, increased filopodia outgrowth in CECs for TNT formation was associated with oxidative inflammation-activated NFκB/TNFαip2 signaling pathways that could be attenuated by reactive oxygen species scavenger N-acetylcysteine (NAC) treatment. Furthermore, MSCs grown on a decellularized porcine corneal scaffold were transplanted onto an alkali-injured eye in a rabbit model. Enhanced corneal wound healing was evident following healthy MSC scaffold transplantation. And transferred mitochondria was detected in corneal epithelium. In conclusion, mitochondrial transfer from MSCs provides novel protection for the cornea against oxidative stress-induced mitochondrial damage. This therapeutic strategy may prove relevant for a broad range of mitochondrial diseases.
We have previously shown that transplantation of autologously derived, respiration-competent mitochondria by direct injection into the heart following transient ischemia and reperfusion enhances cell viability and contractile function. To increase the therapeutic potential of this approach, we investigated whether exogenous mitochondria can be effectively delivered through the coronary vasculature to protect the ischemic myocardium and studied the fate of these transplanted organelles in the heart. Langendorff-perfused rabbit hearts were subjected to 30 minutes of ischemia and then reperfused for 10 minutes. Mitochondria were labeled with 18F-rhodamine 6G and iron oxide nanoparticles. The labeled mitochondria were either directly injected into the ischemic region or delivered by vascular perfusion through the coronary arteries at the onset of reperfusion. These hearts were used for positron emission tomography, microcomputed tomography, and magnetic resonance imaging with subsequent microscopic analyses of tissue sections to confirm the uptake and distribution of exogenous mitochondria. Injected mitochondria were localized near the site of delivery; while, vascular perfusion of mitochondria resulted in rapid and extensive dispersal throughout the heart. Both injected and perfused mitochondria were observed in interstitial spaces and were associated with blood vessels and cardiomyocytes. To determine the efficacy of vascular perfusion of mitochondria, an additional group of rabbit hearts were subjected to 30 minutes of regional ischemia and reperfused for 120 minutes. Immediately following regional ischemia, the hearts received unlabeled, autologous mitochondria delivered through the coronary arteries. Autologous mitochondria perfused through the coronary vasculature significantly decreased infarct size and significantly enhanced post-ischemic myocardial function. In conclusion, the delivery of mitochondria through the coronary arteries resulted in their rapid integration and widespread distribution throughout the heart and provided cardioprotection from ischemia-reperfusion injury.
Mitochondria are essential for the onset of hypoxia-induced pulmonary vasoconstriction and pulmonary vascular-remodeling, two major aspects underlying the development of pulmonary hypertension, an incurable disease. However, hypoxia induces relaxation of systemic arteries such as femoral arteries and mitochondrial heterogeneity controls the distinct responses of pulmonary versus femoral artery smooth muscle cells to hypoxia in vitro. The aim of this study was to determine whether mitochondrial heterogeneity can be experimentally exploited in vivo for a potential treatment against pulmonary hypertension. The intact mitochondria were transplanted into Sprague-Dawley rat pulmonary artery smooth muscle cells in vivo via intravenous administration. The immune-florescent staining and ultrastructural examinations on pulmonary arteries confirmed the intracellular distribution of exogenous mitochondria and revealed the possible mitochondrial transfer from pulmonary artery endothelial cells into smooth muscle cells in part through their intercellular space and intercellular junctions. The transplantation of mitochondria derived from femoral artery smooth muscle cells inhibited acute hypoxia-triggered pulmonary vasoconstriction, attenuated chronic hypoxia-induced pulmonary vascular remodeling, and thus prevented the development of pulmonary hypertension or cured the established pulmonary hypertension in rats exposed to chronic hypoxia. Our findings suggest that mitochondrial transplantation possesses potential implications for exploring a novel therapeutic and preventive strategy against pulmonary hypertension..
Mitochondria play a key role in the homeostasis of the vast majority of the body's cells. In the myocardium where mitochondria constitute 30 % of the total myocardial cell volume, temporary attenuation or obstruction of blood flow and as a result oxygen delivery to myocardial cells (ischemia) severely alters mitochondrial structure and function. These alterations in mitochondrial structure and function occur during ischemia and continue after blood flow and oxygen delivery to the myocardium is restored, and significantly decrease myocardial contractile function and myocardial cell survival. We hypothesized that the augmentation or replacement of mitochondria damaged by ischemia would provide a mechanism to enhance cellular function and cellular rescue following the restoration of blood flow. To test this hypothesis we have used a model of myocardial ischemia and reperfusion. Our studies demonstrate that the transplantation of autologous mitochondria, isolated from the patient's own body, and then directly injected into the myocardial during early reperfusion augment the function of native mitochondria damaged during ischemia and enhances myocardial post-ischemic functional recovery and cellular viability. The transplanted mitochondria act both extracellularly and intracellularly. Extracellularly, the transplanted mitochondria enhance high energy synthesis and cellular adenosine triphosphate stores and alter the myocardial proteome. Once internalized the transplanted mitochondria rescue cellular function and replace damaged mitochondrial DNA. There is no immune or auto-immune reaction and there is no pro-arrhythmia as a result of the transplanted mitochondria. Our studies and those of others demonstrate that mitochondrial transplantation can be effective in a number of cell types and diseases. These include cardiac and skeletal muscle, pulmonary and hepatic tissue and cells and in neuronal tissue. In this review we discuss the mechanisms leading to mitochondrial dysfunction and the effects on cellular function. We provide a methodology for the isolation of mitochondria to allow for clinical relevance and we discuss the methods we and others have used for the uptake and internalization of mitochondria. We foresee that mitochondrial transplantation will be a valued treatment in the armamentarium of all clinicians and surgeons for the treatment of varied ischemic disorders, mitochondrial diseases and related disorders.
There is emerging evidence that stem cells can rejuvenate damaged cells by mitochondrial transfer. Earlier studies show that epithelial mitochondrial dysfunction is critical in asthma patho-genesis. Here we show for the first time that Miro1, a mitochon-drial Rho-GTPase, regulates intercellular mitochondrial movement from mesenchymal stem cells (MSC) to epithelial cells (EC). We demonstrate that overexpression of Miro1 in MSC (MSCmiro Hi
Mitochondrial damage and dysfunction occurs during ischemia and significantly modulates cardiac function and cell survival during reperfusion. We hypothesized that transplantation of autologously-derived mitochondria immediately prior to reperfusion would ameliorate these effects. New Zealand White rabbits were used for regional ischemia (RI) achieved by temporarily snaring the left anterior descending artery for 30 min. Following 29 min RI, autologously-derived mitochondria (RI-Mitochondria; 9.7 ± 1.7 × 10(6)/ml) or vehicle alone (RI-Vehicle) were directly injected into the RI zone and the hearts were allowed to recover for 4 weeks. Mitochondrial transplantation significantly decreased (P < 0.05) creatine kinase MB, cardiac troponin-I and apoptosis in the RI zone. Infarct size following 4 weeks recovery was significantly decreased in RI-Mitochondria (7.9 ± 2.9%) as compared to RI-Vehicle (34.2 ± 3.3%; P < 0.05). Serial echocardiograms showed that RI-Mitochondria hearts returned to normal contraction within 10 minutes after starting reperfusion; however, RI-Vehicle hearts showed persistent hypokinesia in the RI zone at 4 weeks recovery. Electrocardiogram and optical mapping studies showed no arrhythmia was associated with autologously-derived mitochondrial transplantation. In vivo and in vitro studies show that the transplanted mitochondria are evident in the interstitial spaces, are internalized by cardiomyocytes 2 to 8 hours after transplantation. The transplanted mitochondria enhanced oxygen consumption, high energy phosphate synthesis and the induction of cytokine mediators and proteomic pathways important in preserving myocardial energetics, cell viability and enhanced post-infarct cardiac function. Transplantation of autologously-derived mitochondria provides a novel technique to protect the heart from ischemia-reperfusion injury.
Bone marrow-derived stromal cells (BMSCs) protect against acute lung injury (ALI). To determine the role of BMSC mitochondria in this protection, we airway-instilled mice first with lipopolysaccharide (LPS) and then with either mouse BMSCs (mBMSCs) or human BMSCs (hBMSCs). Live optical studies revealed that the mBMSCs formed connexin 43 (Cx43)-containing gap junctional channels (GJCs) with the alveolar epithelia in these mice, releasing mitochondria-containing microvesicles that the epithelia engulfed. The presence of BMSC-derived mitochondria in the epithelia was evident optically, as well as by the presence of human mitochondrial DNA in mouse lungs instilled with hBMSCs. The mitochondrial transfer resulted in increased alveolar ATP concentrations. LPS-induced ALI, as indicated by alveolar leukocytosis and protein leak, inhibition of surfactant secretion and high mortality, was markedly abrogated by the instillation of wild-type mBMSCs but not of mutant, GJC-incompetent mBMSCs or mBMSCs with dysfunctional mitochondria. This is the first evidence, to our knowledge, that BMSCs protect against ALI by restituting alveolar bioenergetics through Cx43-dependent alveolar attachment and mitochondrial transfer.
Mesenchymal stem cells (MSCs), which potentially transdifferentiate into multiple cell types, are increasingly reported to be beneficial in models of organ system injury. However, the molecular mechanisms underlying interactions between MSCs and host cells, in particular endothelial cells (ECs), remain unclear. We show here in a matrigel angiogenesis assay that MSCs are capable of inhibiting capillary growth. After addition of MSCs to EC-derived capillaries in matrigel at EC:MSC ratio of 1:1, MSCs migrated toward the capillaries, intercalated between ECs, established Cx43-based intercellular gap junctional communication (GJC) with ECs, and increased production of reactive oxygen species (ROS). These events led to EC apoptosis and capillary degeneration. In an in vivo tumor model, direct MSC inoculation into subcutaneous melanomas induced apoptosis and abrogated tumor growth. Thus, our findings show for the first time that at high numbers, MSCs are potentially cytotoxic and that when injected locally in tumor tissue they might be effective antiangiogenesis agents suitable for cancer therapy.
Previously, we demonstrated that ischemia induces mitochondrial damage and dysfunction that persist throughout reperfusion and impact negatively on postischemic functional recovery and cellular viability. We hypothesized that viable respiration-competent mitochondria, isolated from tissue unaffected by ischemia and then injected into the ischemic zone just before reperfusion, would enhance postischemic functional recovery and limit infarct size. New Zealand White rabbits (n = 52) were subjected to 30 min of equilibrium and 30 min of regional ischemia (RI) induced by snaring the left anterior descending coronary artery. At 29 min of RI, the RI zone was injected with vehicle (sham control and RI vehicle) or vehicle containing mitochondria (7.7 x 10(6) +/- 1.5 x 10(6)/ml) isolated from donor rabbit left ventricular tissue (RI-Mito). The snare was released at 30 min of RI, and the hearts were reperfused for 120 min. Our results show that left ventricular peak developed pressure and systolic shortening in RI-Mito hearts were significantly enhanced (P < 0.05 vs. RI-vehicle) to 75% and 83% of equilibrium value, respectively, at 120 min of reperfusion compared with 57% and 62%, respectively, in RI-vehicle hearts. Creatine kinase-MB, cardiac troponin I, and infarct size relative to area at risk were significantly decreased in RI-Mito compared with RI-vehicle hearts (P < 0.05). Confocal microscopy showed that injected mitochondria were present and viable after 120 min of reperfusion and were distributed from the epicardium to the subendocardium. These results demonstrate that viable respiration-competent mitochondria, isolated from tissue unaffected by ischemia and then injected into the ischemic zone just before reperfusion, significantly enhance postischemic functional recovery and cellular viability.
Objectives
To report outcomes in a pilot study of autologous mitochondrial transplantation (MT) in pediatric patients requiring postcardiotomy extracorporeal membrane oxygenation (ECMO) for severe refractory cardiogenic shock after ischemia-reperfusion injury (IRI).
Methods
A single-center retrospective study of patients requiring ECMO for postcardiotomy cardiogenic shock following IRI between May 2002 and December 2018 was performed. Postcardiotomy IRI was defined as coronary artery compromise followed by successful revascularization. Patients undergoing revascularization and subsequent MT were compared with those undergoing revascularization alone (Control).
Results
Twenty-four patients were included (MT, n = 10; Control, n = 14). Markers of systemic inflammatory response and organ function measured 1 day before and 7 days following revascularization did not differ between groups. Successful separation from ECMO—defined as freedom from ECMO reinstitution within 1 week after initial separation—was possible for 8 patients in the MT group (80%) and 4 in the Control group (29%) (P = .02). Median circumferential strain immediately following IRI but before therapy was not significantly different between groups. Immediately following separation from ECMO, ventricular strain was significantly better in the MT group (−23.0%; range, −20.0% to −28.8%) compared with the Control group (−16.8%; range, −13.0% to −18.4%) (P = .03). Median time to functional recovery after revascularization was significantly shorter in the MT group (2 days vs 9 days; P = .02). Cardiovascular events were lower in the MT group (20% vs 79%; P < .01). Cox regression analysis showed higher composite estimated risk of cardiovascular events in the Control group (hazard ratio, 4.6; 95% confidence interval, 1.0 to 20.9; P = .04)
Conclusions
In this pilot study, MT was associated with successful separation from ECMO and enhanced ventricular strain in patients requiring postcardiotomy ECMO for severe refractory cardiogenic shock after IRI.
Acute ischemia stroke (AIS) is one of the leading causes of mortality and disability worldwide, and its neurological impacts are devastating and permanent. There is no efficient and real treatment for acute ischemia stroke so far. Therefore, development of efficient therapeutic strategies is under focus of investigations by basic and clinical scientists. Brain is one of the organs with high energy consumption and metabolism. Hence, its functionality is highly dependent on mitochondrial activity and integrity. Therefore, mitochondria play a vital homeostatic role in neurons physiology and mitochondrial dysfunction implications have been reported in a variety of nervous system diseases including acute ischemia stroke. In an attempt to investigate and introduce a novel potential therapeutic strategy for AIS, we isolated healthy mitochondria from human umbilical cord derived mesenchymal stem cells (hUC-MSCs) followed by their intracerebroventricular transplantation in a rat model of ischemia, i.e. middle cerebral artery occlusion (MCAO). Here we report that the mitochondrial transplantation ameliorated the reperfusion/ischemia-induced damages as reflected by declined blood creatine phosphokinase level, abolished apoptosis, decreased astroglyosis and microglia activation, reduced infarct size, and improved motor function. Although further preclinical and clinical studies are required, our findings strongly suggest that transplantation of MSCs-derived mitochondria is a suitable, potential and efficient therapeutic option for acute ischemia stroke.
The effect of dysfunctional mitochondria in several cell pathologies has been reported in renal diseases, including diabetic nephropathy and acute kidney injury. Previous studies have reported that mitochondrial transplantation provided surprising results in myocardial and liver ischemia, as well as in Parkinson's disease. We aimed to investigate the beneficial effects of isolated mitochondria transplantation from mesenchymal stem cells (MSCs) in vivo, to mitigate renal damage that arises from doxorubicin‐mediated nephrotoxicity and its action mechanism. In this study, a kidney model of doxorubicin‐mediated nephrotoxicity was used and isolated mitochondria from MSCs were transferred to the renal cortex of rats. The findings showed that the rate of isolated mitochondria from MSCs maintains sufficient membrane integrity, and was associated with a beneficial renal therapeutic effect. Following doxorubicin‐mediated renal injury, isolated mitochondria or vehicle infused into the renal cortex and rats were monitored for five days. This study found that mitochondrial transplantation decreased cellular oxidative stress and promoted regeneration of tubular cells after renal injury (P < .001, P = .009). Moreover, mitochondrial transplantation reduced protein accumulation of tubular cells and reversed renal deficits (P = .01, P < .001). Mitochondrial transplantation increased Bcl‐2 levels, and caspase‐3 levels decreased in injured renal cells (P < .015, P < .001). Our results provide a direct link between mitochondria dysfunction and doxorubicin‐mediated nephrotoxicity and suggest a therapeutic effect of transferring isolated mitochondria obtained from MSCs against renal injury. To our knowledge, this study is the first study in the literature that showed good therapeutic effects of mitochondrial transplantation in a nephrotoxicity model, which is under‐researched.
Neurons and glia maintain central nervous system (CNS) homeostasis through diverse mechanisms of intra- and intercellular signaling. Some of these interactions include the exchange of soluble factors between cells via direct cell-to-cell contact for both short and long-distance transfer of biological materials. Transcellular transfer of mitochondria has emerged as a key example of this communication. This transcellular transfer of mitochondria are dynamically involved in the cellular and tissue response to CNS injury and play beneficial roles in recovery. This review highlights recent research addressing the cause and effect of intra- and intercellular mitochondrial transfer with a specific focus on the future of mitochondrial transplantation therapy. We believe that mitochondrial transfer plays a crucial role during bioenergetic crisis/deficit, but the quality, quantity and mode of mitochondrial transfer determines the protective capacity for the receiving cells. Mitochondrial transplantation is a new treatment paradigm and will overcome the major bottleneck of traditional approach of correcting mitochondria-related disorders.
Autologous mitochondrial transplantation for myocardial protection is feasible, safe and beneficial; however, the mechanisms by which these effects are achieved are uncertain.
Stroke remains a devastating disease with limited treatment options, despite our growing understanding of its pathology. While ischemic stroke is traditionally characterized by a blockage of blood flow to the brain, this may coincide with reduced blood circulation to the eye, resulting in retinal ischemia, which may in turn lead to visual impairment. Although effective treatment options for retinal ischemia are similarly scarce, new evidence suggests that deleterious changes to mitochondrial structure and function play a major role in both cerebral and retinal ischemia pathologies. Prior studies establish that astrocytes transfer healthy mitochondria to ischemic neurons following stroke; however, this alone is not enough to significantly mitigate the damage caused by primary and secondary cell death. Thus, stem cell-based regenerative medicine targeting amelioration of ischemia-induced mitochondrial dysfunction via the transfer of functional mitochondria to injured neural cells represents a promising approach to improve stroke outcomes for both cerebral and retinal ischemia. In this review, we evaluate recent laboratory evidence supporting the remedial capabilities of mitochondrial transfer as an innovative stroke treatment. In particular, we examine exogenous stem cell transplants in their potential role as suppliers of healthy mitochondria to neurons, brain endothelial cells, and retinal cells.
Impact statement
Stroke constitutes a global health crisis, yet potent, applicable therapeutic options remain effectively inaccessible for many patients. To this end, stem cell transplants stand as a promising stroke treatment and as an emerging subject of research for cell-based regenerative medicine. This is the first review to synthesize the implications of stem cell-derived mitochondrial transfer in both the brain and the eye. As such, this report carries fresh insight into the commonalities between the two stroke-affected organs. We present the findings of this developing area of research inquiry with the hope that our evaluation may advance the use of stem cell transplants as viable therapeutic alternatives for ischemic stroke and related disorders characterized by mitochondrial dysfunction. Such lab-to-clinic translational advancement has the potential to save and improve the ever increasing millions of lives affected by stroke.
Objective:
To investigate preischemic intracoronary autologous mitochondrial transplantation (MT) as a therapeutic strategy for prophylactic myocardial protection in a porcine model of regional ischemia-reperfusion injury (IRI).
Methods:
The left coronary artery was cannulated in Yorkshire pigs (n = 26). Mitochondria (1 × 109) or buffer (vehicle [Veh]) were delivered as a single bolus (MTS) or serially (10 injections over 60 minutes; MTSS). At 15 minutes after injection, the heart was subjected to temporary regional ischemia (RI) by snaring the left anterior descending artery. After 30 minutes of RI, the snare was released, and the heart was reperfused for 120 minutes.
Results:
Coronary blood flow (CBF) and myocardial function were increased temporarily during the pre-RI period. Following 30 minutes of RI, MTS and MTSS hearts had significantly increased CBF that persisted throughout reperfusion (Veh vs MTS and MTSS; P = .04). MTS and MTSS showed a significantly enhanced ejection fraction (Veh vs MTS, P < .001; Veh vs MTSS, P = .04) and developed pressure (Veh vs MTS, P < .001; Veh vs MTSS, P = .03). Regional function, assessed through segmental shortening (Veh vs MTS, P = .03; Veh vs MTSS, P < .001), fractional shortening (Veh vs MTS, P < .001; Veh vs MTSS, P = .04), and strain analysis (Veh vs MTS, P = .002; Veh vs MTSS, P = .003), was also significantly improved. Although there was no difference in the area at risk between treatment groups, infarct size was significantly reduced in both MT groups (Veh vs MTS and MTSS, P < .001).
Conclusions:
Preischemic MT by single or serial intracoronary injections provides prophylactic myocardial protection from IRI, significantly decreasing infarct size and enhancing global and regional function.
Background:
We have previously demonstrated the efficacy of mitochondrial transplantation (MT) for the treatment of ischemia-reperfusion injury (IRI). We now investigate the efficacy of delayed MT by intracoronary administration in a model of regional IRI as a strategy for cardioprotection.
Methods:
Female Yorkshire pigs (40-50 kg; n = 16) underwent 30 minutes of ischemia by snaring of the left anterior descending artery, and the hearts were then reperfused for 120 minutes. At that point, vehicle only or autologous mitochondria (1 × 109 in 5 mL of vehicle) were delivered as a bolus to the left coronary ostium, followed by a further 120-minute reperfusion.
Results:
Echocardiographic analysis demonstrated that hearts receiving delayed MT after regional IRI had enhanced ejection fraction (P = .019), fractional shortening (P = .022), and fractional area change (P = .011) at 240 minutes of reperfusion compared with the untreated pigs. At the end of reperfusion there was a difference between the groups in measures of global left ventricular (LV) function such as LV end-diastolic pressure (P = .015) and rate of rise of LV pressure (P = .021). No significant differences were found between the groups in the area at risk (P = .48). Infarct size (% area at risk) was significantly decreased in hearts receiving MT compared with hearts receiving vehicle only (P < .001).
Conclusions:
Delayed MT by intracoronary injection appreciably decreases myocardial infarct size, increasing regional and global myocardial function. These results suggest that this can be a viable treatment modality in IRI, thus reducing long-term morbidity and mortality in cardiac surgical patients.
Failure of autophagy induction results in the accumulation of abnormal mitochondria to cause neurodegenerative diseases. Artificial autophagy activation by the mitochondrial delivery of polyrotaxane with autophagy inducing activity is achived...
The dysfunction of mitochondria plays important roles in the development of depression. Interestingly, increasing numbers of evidence show the therapeutic benefits of mitochondria transfer. Therefore, we hypothesized that injection of exogenous mitochondria would contribute to ameliorate depressive-like symptoms. In this study, the antidepressant-like effect of intravenous isolated mitochondria was evaluated on a lipopolysaccharide (LPS)- induced model of depression. The depressive-like behaviors were assessed using forced swim test (FST), tail suspension test (TST)and sucrose preference test. Besides, the neurogenesis, expression of brain-derived neurotrophic factor (BDNF), glial activation, neuroinflammation, oxidative stress and ATP production were determined in the hippocampus. The results showed that treatment of isolated mitochondria decreased the immobility time of mice in the FST and TST, and attenuated the decrease in sucrose preference test. Moreover, isolated mitochondria significantly reduced the activation of astrocyte and microglia as well as neuroinflammation (i.e. 1 L-1β, TNF-α and COX-2), increased BDNF expression and neurogenesis, restored the dysfunction of ATP production and oxidative stress in inflammation- induced depression. Taken together, the data suggested for the first time that injection of isolated mitochondria ameliorated LPS- induced depressive-like behaviors. The new discovery for the present study provides that mitochondrial transplantation might act as a new therapeutic strategy for MDD.
Our previous studies reported that pharmacological maintenance of mitochondrial bioenergetics after experimental spinal cord injury (SCI) provided functional neuroprotection. Recent evidence indicates that endogenous mitochondrial transfer is neuroprotective as well, and so we extended these studies with a novel approach to transplant exogenous mitochondria into the injured rat spinal cord. Using a rat model of L1/L2 contusion SCI, we herein report that transplantation of exogenous mitochondria derived from either cell culture or syngeneic leg muscle maintain acute bioenergetics of the injured spinal cord in a concentration-dependent manner. Moreover, transplanting transgenically-labeled (tGFP) PC-12 derived mitochondria allowed for visualization of their incorporation in both a time-dependent and cell-specific manner at 24 hr, 48 hr and 7 days post injection. tGFP mitochondria colocalized with multiple resident cell types, though they were absent in neurons. Despite their contribution to the maintenance of normal bioenergetics, mitochondrial transplantation did not yield long-term functional neuroprotection as assessed by overall tissue sparing or recovery of motor and sensory functions. These experiments are the first to investigate mitochondrial transplantation as a therapeutic approach to treat spinal cord injury. Our initial bioenergetic results are encouraging, and though they did not translate with improved long-term outcome measures, caveats and technical hurdles are discussed that can be addressed in future studies to potentially increase long-term efficacy of transplantation strategies.
It has been reported that transplanting native cells would lack efficiency without producing artificial cell-tissue, due to the exaggerated oxidative stress in doxorubicin-induced cardiomyopathy. We attempted to activate cardiac progenitor cells (CPCs) by delivering resveratrol to mitochondria using a mitochondrial drug delivery system (MITO-Porter system). We first evaluated the viability of H9c2 cells (a cardio myoblast cell line) after doxorubicin treatment, where H9c2 cells were co-cultured with or without the mitochondria activated CPCs (referred to herein as MITO cell). We next evaluated the survival rate of doxorubicin treated mice, with or without the injection of MITO cells into the myocardium. Finally, we examined the molecular mechanism of the cell therapy by detecting oxidative stress and the induction of apoptosis in addition to quantification of the mRNA and protein levels about oxidative phosphorylation (OXPHOS). The MITO cell transplanted mice lived significantly longer than the conventional CPC transplanted ones. Oxidative stress and massive cell death were both significantly reduced in the MITO cell transplanted hearts, in which the expression levels of OXPHOS protein and gene were also higher than the control group. In doxorubicin-induced cardiomyopathy, the transplantation of MITO cells, which possess activated mitochondria, is more efficient compared to conventional CPC transplantation.
Background:
Proper mitochondrial function is essential to maintain normal cellular bioenergetics and ionic homeostasis. In instances of severe tissue damage, such as traumatic brain and spinal cord injury, mitochondria become damaged and unregulated leading to cell death. The relatively unexplored field of mitochondrial transplantation following neurotrauma is based on the theory that replacing damaged mitochondria with exogenous respiratory-competent mitochondria can restore overall tissue bioenergetics.
New method:
We optimized techniques in vitro to prepare suspensions of isolated mitochondria for transplantation in vivo. Mitochondria isolated from cell culture were genetically labeled with turbo-green fluorescent protein (tGFP) for imaging and tracking purposes in vitro and in vivo.
Results:
We used time-lapse confocal imaging to reveal the incorporation of exogenous fluorescently-tagged mitochondria into PC-12 cells after brief co-incubation. Further, we show that mitochondria can be injected into the spinal cord with immunohistochemical evidence of host cellular uptake within 24hours.
Comparison to existing methods:
Our methods utilize transgenic fluorescent labeling of mitochondria for a nontoxic and photostable alternative to other labeling methods. Substrate addition to isolated mitochondria helped to restore state III respiration at room temperature prior to transplantation. These experiments delineate refined methods to use transgenic cell lines for the purpose of isolating well coupled mitochondria that have a permanent fluorescent label that allows real time tracking of transplanted mitochondria in vitro, as well as imaging in situ.
Conclusions:
These techniques lay the foundation for testing the potential therapeutic effects of mitochondrial transplantation following spinal cord injury and other animal models of neurotrauma.
Mitochondrial transplantation is a novel therapeutic intervention to treat ischemia/reperfusion related disorders. The method for mitochondrial transplantation is simple and rapid and can be delivered to the end organ either by direct injection or vascular infusion. In this review, we provide mechanistic and histological studies in large animal models and present data to show clinical efficacy in human patients.
Although restoration of mitochondrial function in mitochondrial diseases through peptide-mediated mitochondrial delivery (PMD) has been demonstrated in vitro, the in vivo therapeutic efficacy of PMD in Parkinson's disease (PD) has yet to be determined. In this study, we compared the functionality of mitochondrial transfer with or without Pep-1 conjugation in neurotoxin (6-hydroxydopamine, 6-OHDA)-induced PC12 cells and PD rat models. We injected mitochondria into the medial forebrain bundle (MFB) of the PD rats after subjecting the nigrostriatal pathway to a unilateral 6-OHDA lesion for 21 days, and we verified the effectiveness of the mitochondrial graft in enhancing mitochondrial function in the soma of the substantia nigra (SN) neuron through mitochondrial transport dynamics in the nigrostriatal circuit. The result demonstrated that only PMD with allogeneic and xenogeneic sources significantly sustained mitochondrial function to resist the neurotoxin-induced oxidative stress and apoptotic death in the rat PC12 cells. The remaining cells exhibited a greater capability of neurite outgrowth. Furthermore, allogeneic/xenogeneic transplantation of peptide-labeled mitochondria after 3 months improved the locomotive activity in the PD rats. This increase was accompanied by a marked decrease in dopaminergic neuron loss in the substantia nigra pars compacta (SNc) and consistent enhancement of tyrosine hydroxylase-positive immunoreaction of dopaminergic neurons in the SNc and striatum. We also observed that in the SN dopaminergic neuron in the treated PD rats, mitochondrial complex I protein and mitochondrial dynamics were restored, thus ameliorating the oxidative DNA damage. Moreover, we determined signal translocation of graft allogeneic mitochondria from the MFB to the calbindin-positive SN neuron, which demonstrated the regulatory role of mitochondrial transport in alleviating 6-OHDA-induced degeneration of dopaminergic neurons.
Ovarian aging is characterized by a decline in both the total number and overall quality of oocytes, the latter of which has been experimentally tied to mitochondrial dysfunction. Clinical studies in the late 1990s demonstrated that transfer of cytoplasm aspirated from eggs of young female donors into eggs of infertile women at the time of intracytoplasmic sperm injection improved pregnancy success rates. However, donor mitochondria were identified in offspring, and the United States Food and Drug Administration raised questions about delivery of foreign genetic material into human eggs at the time of fertilization. Accordingly, heterologous cytoplasmic transfer, while promising, was in effect shut down as a clinical protocol. The recent discovery of adult oogonial (oocyte-generating) stem cells in mice, and subsequently in women, has since re-opened the prospects of delivering a rich source of pristine and patient-matched germline mitochondria to boost egg health and embryonic developmental potential without the need for young donor eggs to obtain cytoplasm. Herein we overview the science behind this new protocol, which has been patented and termed autologous germline mitochondrial energy transfer, and its use to date in clinical studies for improving pregnancy success in women with a prior history of assisted reproduction failure.
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Background:
Mitochondrial dysfunction has been suggested as a major cause of age-induced decline in oocyte quality. In the past, donor oocyte cytoplasmic transfer showed some success but was abandoned due to the concerns with heteroplasmy. Recent studies indicated presence of oogonial precursor cells (OPCs) in the human ovary, which could be an autologous source of "healthy mitochondria." We sought to investigate the clinical efficacy of OPC-derived autologous mitochondrial injection (AMI) to improve oocyte quality in women with multiple in vitro fertilization (IVF) failures.
Methods:
The OPCs were isolated from laparoscopically obtained ovarian cortical pieces by cell sorting using a monoclonal anti-vasa homolog (anti-DDX) antibody. They were then disrupted and mitochondria were isolated. Reconstituted mitochondria were injected into each oocyte during intracytoplasmic sperm injection. Paired comparisons were made between the first failed cycles and the post-AMI cycles.
Results:
Of the 15 women undergoing ovarian stimulation, 2 were canceled and 3 decided to pool oocytes for later AMI. In remaining 10 (mean age 34.7 ± 4.1), AMI significantly improved fertilization rates (49.7 ± 31.3 vs 78.3 ± 18.9; P = .03) with a trend for better embryo grades (2.3 ± 0.3 vs 3.1 ± 0.7; P = .08). Four of 10 women conceived after single frozen embryo transfer and 3 after confirmation of diploidy via array comparative genomic hybridization (aCGH) (clinical pregnancy/embryo transfer = 4/10).
Conclusion:
These data show encouraging results for AMI in comparison to previous failed IVF cycles.
There is emerging evidence that stem cells can rejuvenate damaged cells by mitochondrial transfer. Earlier studies show that epithelial mitochondrial dysfunction is critical in asthma pathogenesis. Here we show for the first time that Miro1, a mitochondrial Rho-GTPase, regulates intercellular mitochondrial movement from mesenchymal stem cells (MSC) to epithelial cells (EC). We demonstrate that overexpression of Miro1 in MSC (MSCmiro(Hi)) leads to enhanced mitochondrial transfer and rescue of epithelial injury, while Miro1 knockdown (MSCmiro(Lo)) leads to loss of efficacy. Treatment with MSCmiro(Hi) was associated with greater therapeutic efficacy, when compared to control MSC, in mouse models of rotenone (Rot) induced airway injury and allergic airway inflammation (AAI). Notably, airway hyperresponsiveness and remodeling were reversed by MSCmiro(Hi) in three separate allergen-induced asthma models. In a human in vitro system, MSCmiro(Hi) reversed mitochondrial dysfunction in bronchial epithelial cells treated with pro-inflammatory supernatant of IL-13-induced macrophages. Anti-inflammatory MSC products like NO, TGF-β, IL-10 and PGE2, were unchanged by Miro1 overexpression, excluding non-specific paracrine effects. In summary, Miro1 overexpression leads to increased stem cell repair.
The feasibility of delivering mitochondria using the cell-penetrating peptide Pep-1 for the treatment of MERRF (myoclonic epilepsy with ragged red fibers) syndrome, which is caused by point mutations in the transfer RNA genes of mitochondrial DNA, is examined further using cellular models derived from patients with MERRF syndrome.
Homogenesis of mitochondria (wild-type mitochondria) isolated from normal donor cells with about 83.5% preserved activity were delivered into MERRF fibroblasts by Pep-1 conjugation (Pep-1-Mito).
Delivered doses of 52.5 μg and 105 μg Pep-1-Mito had better delivered efficiency and mitochondrial biogenesis after 15 days of treatment. The recovery of mitochondrial function in deficient cells receiving 3 days of treatment with peptide-mediated mitochondrial delivery was comprehensively demonstrated by restoration of oxidative phosphorylation subunits (complex I, III and IV), mitochondrial membrane potential, adenosine triphosphate synthesis and reduction of reactive oxygen species production. The benefits of enhanced mitochondrial regulation depended on the function of foreign mitochondria and not the existence of mitochondrial DNA and can be maintained for at least 21 days with dramatically elongated mitochondrial morphology. In contrast to delivery of wild-type mitochondria, the specific regulation of Pep-1-Mito during MERRF syndrome progression in cells treated with mutant mitochondria was reflected by the opposite performance, with increase in reactive oxygen species production and matrix metalloproteinase activity.
The present study further illustrates the feasibility of mitochondrial intervention therapy using the novel approach of peptide-mediated mitochondrial delivery and the benefit resulting from mitochondria-organelle manipulation.
BACKGROUND: A recent study showed that the injection of mitochondria isolated from a non-ischemic region mitigated myocardial injury. We tested the protective effects of infusing isolated mitochondria on the reperfusion injury in the liver of rats. METHODS: A partial liver ischemia-reperfusion model in male Wistar rats was used. At 45th minute of liver ischemia, the recipient's spleen was infused with vehicle (I/R-Vehicle group) or vehicle containing isolated mitochondria (7.7 × 10 ± 1.5 × 10/ml, I/R-Mito group). After a 240 minutes' reperfusion, the serum and livers were collected to assess tissue injury. RESULTS: Our results show that the elevation of serum ALT (414.3±67.1 U/Lv.s208.8±30.2 U/L), the necrosis of hepatocytes on H&E staining, increase of positive counts in TUNEL staining (59.5 ± 4.4% vs 24.6 ±9.1%), the expression of cytosolic cytochrome c, cleaved caspase 9 and 4-HNE were all reduced in the I/R-Mito group, compared to the I/R-Vehicle group. The membrane potential of the isolated mitochondria measured by JC-1 fluorescence remained high, and the infused mitochondria were distributed in the liver parenchyma 240 minutes after reperfusion. CONCLUSIONS: These results demonstrate that an intra-splenic infusion of viable mitochondria isolated from the donor prior to reperfusion significantly reduced ischemia-reperfusion injury in the liver.
Mitochondria are pleomorphic organelles that have central roles in cell physiology. Defects in their localization and dynamics lead to human disease. Myosins are actin-based motors that power processes such as muscle contraction, cytokinesis, and organelle transport. Here we report the initial characterization of myosin-XIX (Myo19), the founding member of a novel class of myosin that associates with mitochondria. The 970 aa heavy chain consists of a motor domain, three IQ motifs, and a short tail. Myo19 mRNA is expressed in multiple tissues, and antibodies to human Myo19 detect an approximately 109 kDa band in multiple cell lines. Both endogenous Myo19 and GFP-Myo19 exhibit striking localization to mitochondria. Deletion analysis reveals that the Myo19 tail is necessary and sufficient for mitochondrial localization. Expressing full-length GFP-Myo19 in A549 cells reveals a remarkable gain of function where the majority of the mitochondria move continuously. Moving mitochondria travel for many micrometers with an obvious leading end and distorted shape. The motility and shape change are sensitive to latrunculin B, indicating that both are actin dependent. Expressing the GFP-Myo19 tail in CAD cells resulted in decreased mitochondrial run lengths in neurites. These results suggest that this novel myosin functions as an actin-based motor for mitochondrial movement in vertebrate cells.
A 37-year-old woman with the history of twice spontaneous abortion, who received unfruitful in vitro fertilization and embryo transfer (IVF-ET) for two cycles due to poor embryo quality, underwent the third cycle for autologous granular cell mitochondria transfer of 5 matured oocytes and intracytoplasmic sperm injection (ICSI) in another 4 oocytes. Better embryo quality was resulted by the former technique than by the latter, despite that fertilization was achieved in all the 4 oocytes with the latter operation. Four of the 5 oocytes with mitochondria transfer were fertilized and developed into normal embryos, 3 of which were selected for intrauterine transplantation. Clinical pregnancy with triplets was subsequently obtained, but the development of one fetus accidentally stopped at the fifth week of pregnancy. The woman received five times of immunotherapy with her husband's leukocytes before and after the pregnancy. At the 30 th week of pregnancy, the women was admitted for severe pregnancy-induced hypertension syndrome that failed to respond to a two-week treatment course. Cesarean section was subsequently performed and two normal babies, one boy and one girl, were born on August 6th, 2003, who were taken home after care in neonate wards. This is the first report of the birth of babies born by autologous granular cell mitochondria transfer in Mainland China.
A detailed molecular understanding of mitochondrial fusion and fission in mammalian cells is rapidly emerging. In this report, we demonstrate for the first time cross-species mitochondrial fusion between distantly related species using green and red fluorescent proteins targeted to the mitochondrial matrix. We found that mouse mitochondria were able to efficiently fuse to unmodified mitochondria of human cells and that the contents of the mitochondrial matrix were completely mixed in less than 4h. We also observed that mitochondria from the mtDNA-less (rho(0)) mouse cells can homogeneously fuse to the mitochondria of human cells. We were, however, unable to maintain human mitochondrial DNA in the mouse cells. These results indicate that mitochondrial fusion proteins in mouse and human cells have enough functional homology to mediate efficient cross-species mitochondrial fusion, but mouse nuclear and human mitochondrial genomes have not retained functional compatibility with one another.