Targeted Therapeutic Delivery Using Engineered Exosomes and its Applications in Cardiovascular Diseases
Abstract
Exosomes are 30-120 nm membrane bound vesicles secreted naturally by almost all cells and exist in all body fluids. Accumulating evidence has shown that exosomes contain proteins, lipids, DNA, mRNA, miRNA, and lncRNA that can be transferred from producer cells to recipient cells, facilitating cell-cell communication. As the natural carrier of these signal molecules, exosomes possess many other properties such as stability, biocompatibility, biological barrier permeability, low toxicity, and low immunogenicity, which make them an attractive vehicle for therapeutic delivery. How exosomes target recipient cells in vivo remains largely unknown, however, exosomes are selectively enriched in some transmembrane proteins that can be genetically engineered to display ligands/homing peptides on their surface, which confers exosome targeting capability to cells bearing cognate receptors. With the discovery of many peptides homing to diseased tissues or organs through phage display and in vivo biopanning technologies, there is ample opportunity to explore the potential use of exosome for targeted gene therapy. Here, we briefly review exosome biogenesis, mechanisms of exosome-mediated cell-cell communication, and exosome isolation and purification methods, and specifically focus on the emerging exosome targeting technologies.
Copyright © 2015. Published by Elsevier B.V.
... Each of these methods has its own advantages and disadvantages, with reports indicating that SEC exhibits higher efficacy, purity, scalability and functionality, while microfluidics represents a more innovative approach for rapid and early detection (Sidhom et al. 2020;Liu et al. 2022a, b). Exosomes can mediate their effects locally or systemically in autocrine, paracrine, or endocrine manners and are released in body fluids, like plasma, blood, milk, cerebrospinal fluid (CSF), saliva, urine or amniotic fluid (Edgar 2016;Xitong and Xiaorong 2016;He et al. 2018). Exosomes cooperate in many physiological processes including immune cell interactions, stem cell maintenance, tissue regeneration and development, lactation, coagulation, calcification, embryo implantation, and sex determination or pathological conditions like neurodegenerative diseases, viral/bacterial infection, osteoarthritis and many cardiopulmonary/liver/kidney-related diseases (Keller et al. 2011;Armstrong et al. 2017;Grange et al. 2017;Lou et al. 2017;Sarko and McKinney 2017;Willis et al. 2017). ...
... It should be noted that, although there are many advantages to using extracellular vesicles, this field also suffers from some limitations. Quality control, optimal loading, surface functionalization, heterogeneity, fast clearance and finding the most efficient clinical doses are some of the limitations in this regard (Xitong and Xiaorong 2016;Phinney and Pittenger 2017;Willis et al. 2017;Marbán, 2018;Ferreira et al. 2022). The lack of standard isolation/purification methods (each method can purify distinct types of EVs and subpopulations that can carry different contents to show downstream functions and there is also no consensus on a recommended method with high purity and yield), largescale production (two recent strategies are donor cell pretreatment and genetic engineering), off-target effects, drug loading limitations and reticuloendothelial organ clearance are some of the bottlenecks to name (Meng et al. 2020;Qu et al. 2023) (Fig. 1). ...
... However, scavenger receptor inhibition (Watson et al. 2016;Sarko and McKinney 2017), an active receptor for exosome trapping by immune cells, can relatively overcome their liver clearance. Moreover, any undesirable changes in environmental conditions like temperature, pressure or the presence/ absence of soluble components or cargos can make them aggregated and visible to the mononuclear phagocyte system (MPS) (Batrakova and Kim 2016;Xitong and Xiaorong 2016). There are many ongoing projects to minimize these limitations. ...
Gastric cancer (GC) is one of the most prevalent malignancies in the world, with a high mortality rate in both women and men. Conventional treatments, like chemotherapy, radiotherapy and surgery, are facing some drawbacks like acquired drug resistance and various side effects, leading to cancer recurrence and increased morbidity; thus, development of novel approaches in targeted therapy would be very beneficial. Exosomes, extracellular vesicles with a size distribution of sub-150 nm, interplay in physiological and pathophysiological cell–cell communications and can pave the way for targeted cancer therapy. Accumulating pieces of evidence have indicated that exosomes derived from mesenchymal stem cells (MSC-EXs) can act as a double-edged sword in some cancers. The purpose of this review is to assess the differences between stem cell therapy and exosome therapy. Moreover, our aim is to demonstrate how naïve MSCs transform into GC-MSCs in the tumor microenvironment. Additionally, the tumorigenic and anti-proliferation effects of MSC-EXs derived from different origins were investigated. Finally, we suggest potential modifications and combination options that involve utilizing MSC-EXs from the foreskin and umbilical cord as promising sources to enhance the efficacy of gastric cancer treatment. This approach is presented in contrast to bone marrow cells, which are more heterogeneous, age-related, and are also easily affected by the patient's circulation system.
... Various ligand/homing peptides have been successfully displayed on the surface of exosomes through forced expression of ligand/homing peptides fused in-frame with a transmembrane protein in the parental cells [13,14]. Heart homing peptide (HHP) containing five amino acids CRPPR was previously discovered by phage display, which has been shown to localize in the heart tissue of mice after intravenous injection administration through specific binding to Cysteine-rich protein 2 (CRIP2) [15]. ...
... Exosomes can be manipulated to target specific tissues by surface display of a ligand or homing peptide [14]. To target cardiac tissue, plasmids encoding LAMP2b alone or HHP fused in-frame to LAMP2b were stably expressed in CDCs (Additional file 1: Figure S1), from which LAMP-exosomes (CON-EXO) and HHP-LAMPexosomes (HHP-EXO) were prepared. ...
Exosomes of human cardiosphere-derived cells (CDCs) are very promising for treating cardiovascular disorders. However, the current challenge is inconvenient delivery methods of exosomes for clinical application. The present study aims to explore the potential to enhance the therapeutic effect of exosome (EXO) from human CDCs to myocardial hypertrophy. A heart homing peptide (HHP) was displayed on the surface of exosomes derived from CDCs that were forced to express the HHP fused on the N-terminus of the lysosomal-associated membrane protein 2b (LAMP2b). The cardiomyocyte-targeting capability of exosomes were analyzed and their therapeutic effects were evaluated in a mouse model of myocardial hypertrophy induced by transverse aorta constriction (TAC). The molecular mechanisms of the therapeutic effects were dissected in angiotensin II-induced neonatal rat cardiomyocyte (NRCMs) hypertrophy model using a combination of biochemistry, immunohistochemistry and molecular biology techniques. We found that HHP-exosomes (HHP-EXO) accumulated more in mouse hearts after intravenous delivery and in cultured NRCMs than control exosomes (CON-EXO). Cardiac function of TAC mice was significantly improved with intravenous HHP-EXO administration. Left ventricular hypertrophy was reduced more by HHP-EXO than CON-EXO via inhibition of β-MHC, BNP, GP130, p-STAT3, p-ERK1/2, and p-AKT. Similar results were obtained in angiotensin II-induced hypertrophy of NRCMs, in which the beneficial effects of HHP-EXO were abolished by miRNA-148a inhibition. Our results indicate that HHP-EXO preferentially target the heart and improve the therapeutic effect of CDCs-exosomes on cardiac hypertrophy. The beneficial therapeutic effect is most likely attributed to miRNA-148a-mediated suppression of GP130, which in turn inhibits STAT3/ERK1/2/AKT signaling pathway, leading to improved cardiac function and remodeling.
... Exosomes are another ideal vehicle for delivering therapeutic miRNAs to treat periodontitis due to their biocompatibility, stability, and low immunogenicity (Zheng et al., 2019). In addition, exosomes can be modified by adding specific miRNAs and targeting peptides to enhance their delivery capacity (Xitong and Xiaorong, 2016). However, miRNA therapy for periodontitis is still in its early stages because we lack reliable ways to safely and effectively deliver these molecules to patients. ...
Modeling and remodeling are essential processes in the development and refinement of maxillofacial bones. Dysregulated bone modeling during the developmental stage may lead to maxillofacial bone malformations and malocclusion. Bone remodeling under mechanical loading serves as the biological basis for orthodontic treatment. Although previous reviews have indicated the significance of microRNAs (miRNAs) in bone metabolism, their roles in orchestrating maxillofacial bone modeling and remodeling remain unclear. This review aims to discuss the mechanisms by which miRNAs regulate the morphogenesis and development of maxillofacial bones, as well as their implications for maxillofacial malformations and malocclusion. Moreover, miRNAs participating in maxillofacial bone remodeling and their impacts on cell mechanosensing are also summarized. Given the intricate interplay of cells and signaling pathways, exosomal miRNAs emerge as the orchestrators of the modeling and remodeling processes. The diagnostic and therapeutic potentials of miRNAs are also highlighted in this review for future clinical applications.
... EVs are selectively enriched in some transmembrane proteins that can display ligands/homing peptides on their surface, which could confer RBC-EV targeting capability. 28 Our study showed that compared with MSC-EVs, common exosomal membrane proteins, such as CD63 and CD9, were expressed less in RBC-EVs, while SLC4A1 was expressed more specifically. Then, we screened the peptides that specifically bind to the extracellular segment of the membrane protein SLC4A1 using phage display technology. ...
Extracellular vesicles (EVs) are increasingly used for disease diagnosis and treatment. Among them, red blood cell-derived EVs (RBC-EVs) have attracted great attention due to their abundant sources and low risks of gene transfer (RBC-EVs lack nuclear and mitochondrial DNA). Here, we first revealed the high expression level of membrane protein solute carrier family 4 member 1 (SLC4A1) in RBC-EVs through proteomic analysis. We then identified several binding peptides with high affinity for the SLC4A1 extracellular domain (SLC4A1-EC) from phage display library screening. A high affinity of SLC4A1-EC and the three peptides (XRB2, XRE4, and XRH7) were assessed in vitro using surface plasmon resonance analysis and SDS–polyacrylamide gel electrophoresis (SDS–PAGE). The binding sites of SLC4A1-EC and polypeptides were further predicted by LigPlot + analysis, and the results showed that these three polypeptides could bind to part of the hydrophobic residues of SLC4A1-EC. The binding efficiency of the anchor peptides to the RBC-EVs was further verified by flow cytometry and fluorescence imaging. In conclusion, we successfully screened three specific RBC-EV-targeting peptides which could potentially be utilized for isolating RBC-derived EVs from serum samples. More importantly, this peptide could be coupled with targeting peptides to modify RBC-EVs for drug delivery. Our work will provide a viable method for optimizing the function of RBC-EVs.
... For example, using exosomes as drug delivery vehicles is an important application of exosomes. In recent years, an increasing number of studies have revealed that exosomes could function as attractive biological vesicles for the delivery of biological therapeutics across different biological barriers to target cells [4,156,157] . Compared to available treatments, this method is non-invasive and may be more effective for CVDs. ...
Microvesicles known as exosomes have a diameter of 40 to 160 nm and are derived from small endosomal membranes. Exosomes have attracted increasing attention over the past ten years in part because they are functional vehicles that can deliver a variety of lipids, proteins, and nucleic acids to the target cells they encounter. Because of this function, exosomes may be used for the diagnosis, prognosis and treatment of many diseases. All throughout the world, cardiovascular diseases (CVDs) continue to be a significant cause of death. Because exosomes are mediators of communication between cells, which contribute to many physiological and pathological aspects, they may aid in improving CVD therapies as biomarkers for diagnosing and predicting CVDs. Many studies demonstrated that exosomes are associated with CVDs, such as coronary artery disease, heart failure, cardiomyopathy and atrial fibrillation. Exosomes participate in the progression or inhibition of these diseases mainly through the contents they deliver. However, the application of exosomes in diferent CVDs is not very mature. So further research is needed in this field.
... Studies demonstrated that several Rab family proteins (GTPases), including sub-family Rab27, 35, and 11, act as crucial Exos transport and secretion regulators in these ways. Together with calcium, they were shown to participate in the docking and fusion of MVB with the plasma membrane [90,91]. In this regard, Exos display has allowed us to create recombinant vesicles carrying cytokines or tumor antigens that may or may not have been previously present on Exos [92]. ...
Chimeric antigen receptor natural killer cells (CAR-NK) promote off-the-shelf cellular therapy for solid tumors and malignancy.However,, the development of CAR-NK is due to their immune surveillance uncertainty and cytotoxicity challenge was restricted. Natural killer cell-derived exosome (NK-Exo) combine crucial targeted cellular therapies of NK cell therapies with unique non-toxic Exo as a self-origin shuttle against cancer immunotherapy. This review study covers cytokines, adoptive (autologous and allogenic) NK immunotherapy, stimulatory and regulatory functions, and cell-free derivatives from NK cells. The future path of NK-Exo cytotoxicity and anti-tumor activity with considering non-caspase-independent/dependent apoptosis and Fas/FasL pathway in cancer immunotherapy. Finally, the significance and implication of NK-Exo therapeutics through combination therapy and the development of emerging approaches for the purification and delivery NK-Exo to severe immune and tumor cells and tissues were discussed in detail.
... exosomes) as main tools. Indeed, exosomes (soft extracellular vesicles produced by the cells, 50 to 150 nm in size) have significant biological content, including DNA, RNA and proteins, and thanks to the specific composition of their membranes, are able to target desired organs [7][8][9][10] giving them great potential as selective delivery vectors. Theragnostic nanomaterials have been also incorporated in these vesicles especially in applications against cancer [8,9,[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. ...
Background
Platinum nanoparticles have been demonstrated to have excellent anticancer properties. However, because of the lack of specificity they must be delivered to the tumor in amounts sufficient to reach the desired therapeutic objectives. Interestingly, exosomes are considered as excellent natural selective delivery nanotools, but until know their targeting properties have not being combined with the anticancer properties of platinum nanoparticles.
Results
In this work we combine the targeting capabilities of exosomes and the antitumoral properties of ultrasmall (< 2 nm) platinum nanoparticles as a novel, low toxicity alternative to the use of cisplatin. A mild methodology based on the room temperature CO-assisted in situ reduction of Pt²⁺ precursor was employed to preserve the integrity of exosomes, while generating ultrasmall therapeutic PtNPs directly inside the vesicles. The resulting PtNPs-loaded exosomes constitute a novel hybrid bioartificial system that was readily internalized by the target cells inducing antiproliferative response, as shown by flow cytometry and microscopy experiments in vitro. In vivo Pt-Exos showed antitumoral properties similar to that of cisplatin but with a strongly reduced or in some cases no toxic effect, highlighting the advantages of this approach and its potential for translation to the clinic.
Conclusions
In this study, a nanoscale vector based on ultrasmall PtNPs and exosomes has been created exhibiting antitumoral properties comparable or higher to those of the FDA approved cisplatin. The preferential uptake of PtNPs mediated by exosomal transfer between certain cell types has been exploited to create a selective antitumoral novel bioartificial system. We have demonstrated their anticancer properties both in vitro and in vivo comparing the results obtained with the administration of equivalent amounts of cisplatin, and showing a spectacular reduction of toxicity.
Exosomes are small extracellular vesicles (30–150 nm) that are formed by endocytosis containing complex RNA as well as protein structures and are vital in intercellular communication and can be used in gene therapy and drug delivery. According to the cell sources of origin and the environmental conditions they are exposed to, these nanovesicles are very heterogeneous and dynamic in terms of content (cargo), size and membrane composition. Exosomes are released under physiological and pathological conditions and influence the pathogenesis of cancers through various mechanisms, including angiogenesis, metastasis, immune dysregulation, drug resistance, and tumor growth/development. Gastrointestinal cancer is one of the deadliest types of cancer in humans and can involve organs e.g., the esophagus and stomach, or others such as the liver, pancreas, small intestine, and colon. Early diagnosis is very important in this field because the overall survival of patients is low due to diagnosis in late stages and recurrence. Also, various therapeutic strategies have failed and there is an unmet need for the new therapeutic agents. Exosomes can become promising candidates in gastrointestinal cancers as biomarkers and therapeutic agents due to their lower immunity and passing the main physiological barriers. In this work, we provide a general overview of exosomes, their biogenesis and biological functions. In addition, we discuss the potential of exosomes to serve as biomarkers, agents in cancer treatment, drug delivery systems, and effective vaccines in immunotherapy, with an emphasis on gastrointestinal cancers.
Graphical Abstract
Increased prevalence of cardiovascular disease and potentially life-threatening complications of myocardial infarction (MI) has led to emerging therapeutic approaches focusing on myocardial regeneration and restoration of physiologic function following infarction. Extracellular vesicle (EV) technology has gained attention owing to the biological potential to modulate cellular immune responses and promote the repair of damaged tissue. Also, EVs are involved in local and distant cellular communication following damage and play an important role in initiating the repair process. Vesicles derived from stem cells and cardiomyocytes (CM) are of particular interest due to their ability to promote cell growth, proliferation, and angiogenesis following MI. Although a promising candidate for myocardial repair, EV technology is limited by the short retention time of vesicles and rapid elimination by the body. There have been several successful attempts to address this shortcoming, which includes hydrogel technology for the sustained bioavailability of EVs. This review discusses and summarizes current understanding regarding EV technology in the context of myocardial repair.
Background:
The dysregulation of exosomal microRNAs plays an important role in the progression of hepatocarcinogenesis. In this study, we investigated the therapeutic potential of synthetic exosomal miR-26a against HCC cells and explored the feasibility of tumor-derived exosomes as drug delivery vehicles.
Methods:
Proliferation and migration assays were performed to examine the effects of miR-26a on HCC in vitro. The direct target gene of miR-26a was identified through miRecords analysis and target validation. The transferring efficiency and anti-HCC effect of exosomes with different origin were studied and the optimal miR-26a delivery method was established and verified in vitro and in vivo. In addition, the relationships between prognosis of HCC patients and miR-26a expression in HCC serum and exosomes were retrospectively analyzed.
Results:
Here, we found that tumor cell-derived exosomes were taken in preferentially by HCC cells and promoted HCC progression through Wnt pathway by low-density lipoprotein receptor-related protein 6 (LRP6). HCC cells with vacuolar protein sorting-associated protein 35 knocked down were adopted to generate engineered LRP6-exosomes. The engineered HCC-derived exosomes loading miR-26a inhibited HCC progression in vitro and in vivo effectively. Overexpression of miR-26a impaired the growth and migration of HCC by targeting lymphoid enhancer factor 1 (LEF1). Moreover, low expression of exosomal miR-26a was an independent prognostic factor for recurrence and survival in HCC patients.
Conclusions:
Our findings suggested the exosomal miR-26a could serve as a non-invasive prognostic marker for HCC patients. Genetically modified tumor-derived exosomes showed preferable transfection efficiency but reduced Wnt activity, which provides a novel therapeutic strategy for HCC.
Plasma-derived vesicles hold a promising potential for use in biomedical applications. Two major challenges, however, hinder their implementation into translational tools: (a) the incomplete characterization of the protein composition of plasma-derived vesicles, in the size range of exosomes, as mass spectrometric analysis of plasma sub-components is recognizably troublesome and (b) the limited reach of vesicle-based studies in settings where the infrastructural demand of ultracentrifugation, the most widely used isolation/purification methodology, is not available. In this study, we have addressed both challenges by carrying-out mass spectrometry (MS) analyses of plasma-derived vesicles, in the size range of exosomes, from healthy donors obtained by 2 alternative methodologies: size-exclusion chromatography (SEC) on sepharose columns and Exo-Spin™. No exosome markers, as opposed to the most abundant plasma proteins, were detected by Exo-Spin™. In contrast, exosomal markers were present in the early fractions of SEC where the most abundant plasma proteins have been largely excluded. Noticeably, after a cross-comparative analysis of all published studies using MS to characterize plasma-derived exosomes from healthy individuals, we also observed a paucity of "classical exosome markers." Independent of the isolation method, however, we consistently identified 2 proteins, CD5 antigen-like (CD5L) and galectin-3-binding protein (LGALS3BP), whose presence was validated by a bead-exosome FACS assay. Altogether, our results support the use of SEC as a stand-alone methodology to obtain preparations of extracellular vesicles, in the size range of exosomes, from plasma and suggest the use of CD5L and LGALS3BP as more suitable markers of plasma-derived vesicles in MS.
Renal biopsy is the gold-standard procedure to diagnose most of renal pathologies. However, this invasive method is of limited repeatability and often describes an irreversible renal damage. Urine is an easily accessible fluid and urinary extracellular vesicles (EVs) may be ideal to describe new biomarkers associated with renal pathologies. Several methods to enrich EVs have been described. Most of them contain a mixture of proteins, lipoproteins and cell debris that may be masking relevant biomarkers. Here, we evaluated size-exclusion chromatography (SEC) as a suitable method to isolate urinary EVs. Following a conventional centrifugation to eliminate cell debris and apoptotic bodies, urine samples were concentrated using ultrafiltration and loaded on a SEC column. Collected fractions were analysed by protein content and flow cytometry to determine the presence of tetraspanin markers (CD63 and CD9). The highest tetraspanin content was routinely detected in fractions well before the bulk of proteins eluted. These tetraspanin-peak fractions were analysed by cryo-electron microscopy (cryo-EM) and nanoparticle tracking analysis revealing the presence of EVs.
When analysed by sodium dodecyl sulphate–polyacrylamide gel electrophoresis, tetraspanin-peak fractions from urine concentrated samples contained multiple bands but the main urine proteins (such as Tamm–Horsfall protein) were absent. Furthermore, a preliminary proteomic study of these fractions revealed the presence of EV-related proteins, suggesting their enrichment in concentrated samples. In addition, RNA profiling also showed the presence of vesicular small RNA species.
To summarize, our results demonstrated that concentrated urine followed by SEC is a suitable option to isolate EVs with low presence of soluble contaminants. This methodology could permit more accurate analyses of EV-related biomarkers when further characterized by -omics technologies compared with other approaches.
Extracellular vesicles (EVs) are lipid membrane vesicles released by cells. They carry active biomolecules including DNA, RNA, and protein which can be transferred to recipient cells. Isolation and purification of EVs from culture cell media and biofluids is still a major challenge. The most widely used isolation method is ultracentrifugation (UC) which requires expensive equipment and only partially purifies EVs. Previously we have shown that heparin blocks EV uptake in cells, supporting a direct EV-heparin interaction. Here we show that EVs can be purified from cell culture media and human plasma using ultrafiltration (UF) followed by heparin-affinity beads. UF/heparin-purified EVs from cell culture displayed the EV marker Alix, contained a diverse RNA profile, had lower levels of protein contamination, and were functional at binding to and uptake into cells. RNA yield was similar for EVs isolated by UC. We were able to detect mRNAs in plasma samples with comparable levels to UC samples. In conclusion, we have discovered a simple, scalable, and effective method to purify EVs taking advantage of their heparin affinity.
The treatment of myocardial infarction is a major challenge in medicine due to the inability of heart tissue to regenerate. Direct reprogramming of endogenous cardiac fibroblasts into functional cardiomyocytes via the delivery of transcription factor mRNAs has the potential to regenerate cardiac tissue and to treat heart failure. Even though mRNA delivery to cardiac fibroblasts has the therapeutic potential, mRNA transfection in cardiac fibroblasts has been challenging. Herein, we develop an efficient mRNA transfection in cultured mouse cardiac fibroblasts via a polyarginine-fused heart-targeting peptide and lipofectamine complex, termed C-Lipo and demonstrate the partial direct reprogramming of cardiac fibroblasts towards cardiomyocyte cells. C-Lipo enabled the mRNA-induced direct cardiac reprogramming due to its efficient transfection with low toxicity, which allowed for multiple transfections of Gata4, Mef2c, and Tbx5 (GMT) mRNAs for a period of 2 weeks. The induced cardiomyocyte-like cells had α-MHC promoter-driven GFP expression and striated cardiac muscle structure from α-actinin immunohistochemistry. GMT mRNA transfection of cultured mouse cardiac fibroblasts via C-Lipo significantly increased expression of the cardiomyocyte marker genes, Actc1, Actn2, Gja1, Hand2, and Tnnt2, after 2 weeks of transfection. Moreover, this study provides the first direct evidence that the stoichiometry of the GMT reprogramming factors influence the expression of cardiomyocyte marker genes. Our results demonstrate that mRNA delivery is a potential approach for cardiomyocyte generation.
We recently demonstrated that epicardial progenitor cells participate in the regenerative response to myocardial infarction (MI) and factors released in the pericardial fluid (PF) may play a key role in this process. Exosomes are secreted nanovesicles of endocytic origin, identified in most body fluids, which may contain molecules able to modulate a variety of cell functions. Here, we investigated whether exosomes are present in the PF and their potential role in cardiac repair.
Early gene expression studies in 3day-infarcted mouse hearts showed that PF induces epithelial-to-mesenchymal transition (EMT) in epicardial cells. Exosomes were identified in PFs from non-infarcted patients (PFC) and patients with acute MI (PFMI). A shotgun proteomics analysis identified clusterin in exosomes isolated from PFMI but not from PFC. Notably, clusterin has a protective effect on cardiomyocytes after acute MI in vivo and is an important mediator of TGFβ-induced. Clusterin addition to the pericardial sac determined an increase in epicardial cells expressing the EMT marker α-SMA and, interestingly, an increase in the number of epicardial cells ckit(+)/α-SMA(+), 7days following MI. Importantly, clusterin treatment enhanced arteriolar length density and lowered apoptotic rates in the peri-infarct area. Hemodynamic studies demonstrated an improvement in cardiac function in clusterin-treated compared to untreated infarcted hearts.
Exosomes are present and detectable in the PFs. Clusterin was identified in PFMI-exosomes and might account for an improvement in myocardial performance following MI through a framework including EMT-mediated epicardial activation, arteriogenesis and reduced cardiomyocyte apoptosis.
Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
Exosomes are transport vesicles released from cells that contain deoxyribonucleic acid, ribonucleic acid (RNA), and protein [(1)][1]. Exosomes have captured our attention with the explosion of diagnostics to measure the molecular profiles inside these vesicles with the purpose of detecting,
Exosomes are nanometer-sized vesicles released from cells into the blood, where they can transmit signals throughout the body. Shown to act on the heart, exosomes' composition and the signaling pathways they activate have not been explored. We hypothesized that endogenous plasma exosomes can communicate signals to the heart and provide protection against ischemia and reperfusion injury.
This study sought to isolate and characterize exosomes from rats and healthy volunteers, evaluate their cardioprotective actions, and identify the molecular mechanisms involved.
The exosome-rich fraction was isolated from the blood of adult rats and human volunteers and was analyzed by protein marker expression, transmission electron microscopy, and nanoparticle tracking analysis. This was then used in ex vivo, in vivo, and in vitro settings of ischemia-reperfusion, with the protective signaling pathways activated on cardiomyocytes identified using Western blot analyses and chemical inhibitors.
Exosomes exhibited the expected size and expressed marker proteins CD63, CD81, and heat shock protein (HSP) 70. The exosome-rich fraction was powerfully cardioprotective in all tested models of cardiac ischemia-reperfusion injury. We identified a pro-survival signaling pathway activated in cardiomyocytes involving toll-like receptor (TLR) 4 and various kinases, leading to activation of the cardioprotective HSP27. Cardioprotection was prevented by a neutralizing antibody against a conserved HSP70 epitope expressed on the exosome surface and by blocking TLR4 in cardiomyocytes, identifying the HSP70/TLR4 communication axis as a critical component in exosome-mediated cardioprotection.
Exosomes deliver endogenous protective signals to the myocardium by a pathway involving TLR4 and classic cardioprotective HSPs.
Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.
MicroRNAs are crucial in the regulation of cardiovascular disease and represent potential therapeutic targets to decrease abdominal aortic aneurysm (AAA) expansion. The aim of this study was to identify circulating microRNAs associated with AAA.
Some 754 microRNAs in whole-blood samples from 15 men with an AAA and ten control subjects were quantified using quantitative reverse transcriptase-PCR. MicroRNAs demonstrating a significant association with AAA were validated in peripheral blood and plasma samples of men in the following groups (40 in each): healthy controls, controls with peripheral arterial disease (PAD), men with a small AAA (30-54 mm), those with a large AAA (over 54 mm), and those following AAA repair. MicroRNA expression was also assessed in aortic tissue.
Twenty-nine differentially expressed microRNAs were identified in the discovery study. Validation study revealed that let-7e (fold change (FC) -1·80; P = 0·001), miR-15a (FC -2·24; P < 0·001) and miR-196b (FC -2·26; P < 0·001) were downregulated in peripheral blood from patients with an AAA, and miR-411 was upregulated (FC 5·90; P = 0·001). miR-196b was also downregulated in plasma from the same individuals (FC -3·75; P = 0·029). The same miRNAs were similarly expressed differentially in patients with PAD compared with healthy controls. Validated and predicted microRNA targets identified through miRWalk revealed that these miRNAs were all regulators of AAA-related genes (vascular cell adhesion molecule 1, intercellular cell adhesion molecule 1, DAB2 interacting protein, α1-antitrypsin, C-reactive protein, interleukin 6, osteoprotegerin, methylenetetrahydrofolate reductase, tumour necrosis factor α).
In this study, circulating levels of let-7e, miR-15a, miR-196b and miR-411 were differentially expressed in men with an AAA compared with healthy controls, but also differentially expressed in men with PAD. Modulation of these miRNAs and their target genes may represent a new therapeutic pathway to affect the progression of AAA and atherosclerosis.
© 2015 BJS Society Ltd Published by John Wiley & Sons Ltd.
The complexity of mechanisms driving protein sorting into exosomes is only beginning to emerge. In a paper recently published in Cell Research, Roucourt et al. report that trimming of heparan sulfate side chains of syndecans by endosomal heparanase facilitates sorting into exosomes by the formation of tight syndecan clusters that are recruited by the multivalent adaptor syntenin to the ALIX-ESCRT sorting machinery at endosomes.