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Characterization of isolated exosomes. a Western blotting analysis revealed the proteins of TSG101 and CD9 were enriched in exosomes. b Scanning electron microscopy was used to identify the vesicles isolated from reparative M2-like macrophages. c Particle size distribution of the exosomes secreted by reparative M2-like macrophages were investigated by dynamic light scattering (DLS) analysis. Exosomes derived from reparative M2-like macrophages was labeled with red fluorescence DiI and co-cultured with BMSCs (d) and BMDM (e) respectively, red fluorescence represents exosomes in BMSCs or BMDM
Source publication
Background
Periodontitis is characterized by progressive inflammation and alveolar bone loss resulting in tooth loss finally. Macrophages including pro-inflammatory M1-like macrophages and reparative M2-like macrophages play a vital role in inflammation and tissue homeostasis in periodontitis. Among them, reparative M2-like macrophages have been sh...
Citations
... M1 macrophages dominate the initial phase of periodontitis and are activated by exogenous pathogen-associated and endogenous damage-associated molecular patterns, exhibiting potent phagocytosis and enhanced production of proinflammatory cytokines, including IL-1β, TNF-α, IL-6, IL-12 and IL-23, which clear pathogenic microorganisms while exerting pro-inflammatory effects, and remove debris and apoptotic cells [32,36,37]. During periodontitis repair and remodeling, M2 macrophages dominate and the expression of M2-associated factors, including vascular endothelial growth factor, transforming growth factor β (TGF-β), arginase (Arg)-1 and IL-10, increases, preventing bone loss and promoting tissue repair and remodeling of the extracellular matrix [38,39]. M1 macrophages are the main phenotype observed in the early stages of inflammation, with a significant decrease in M1 and an increase in M2 macrophages as periodontitis progresses. ...
Periodontitis is a chronic inflammation caused by a bacterial infection and is intimately associated with an overactive immune response. Biomaterials are being utilized more frequently in periodontal therapy due to their designability and unique drug delivery system. However, local and systemic immune response reactions driven by the implantation of biomaterials could result in inflammation, tissue damage, and fibrosis, which could end up with the failure of the implantation. Therefore, immunological adjustment of biomaterials through precise design can reduce the host reaction while eliminating the periodontal tissue's long-term chronic inflammation response. It is important to note that macrophages are an active immune system component that can participate in the progression of periodontal disease through intricate polarization mechanisms. And modulating macrophage polarization by designing biomaterials has emerged as a new periodontal therapy technique. In this review, we discuss the role of macrophages in periodontitis and typical strategies for polarizing macrophages with biomaterials. Subsequently, we discuss the challenges and potential opportunities of using biomaterials to manipulate periodontal macrophages to facilitate periodontal regeneration.
Graphical Abstract
... In vitro studies have indicated the critical role of macrophage polarization in the onset and progression of periodontitis [67]. The aforementioned results validate that inhibiting M1 macrophage polarization can reduce the expression of inflammatory cytokines in periodontal lesion tissues [74], and inducing M2 macrophages can prevent bone loss [75,76]. Therefore, CSBDX@MOF can promote alveolar bone regeneration by regulating M1/ M2 polarization. ...
Periodontitis is a prevalent chronic inflammatory disease, which leads to gradual degradation of alveolar bone. The challenges persist in achieving effective alveolar bone repair due to the unique bacterial microenvironment’s impact on immune responses. This study explores a novel approach utilizing Metal–Organic Frameworks (MOFs) (comprising magnesium and gallic acid) for promoting bone regeneration in periodontitis, which focuses on the physiological roles of magnesium ions in bone repair and gallic acid's antioxidant and immunomodulatory properties. However, the dynamic oral environment and irregular periodontal pockets pose challenges for sustained drug delivery. A smart responsive hydrogel system, integrating Carboxymethyl Chitosan (CMCS), Dextran (DEX) and 4-formylphenylboronic acid (4-FPBA) was designed to address this problem. The injectable self-healing hydrogel forms a dual-crosslinked network, incorporating the MOF and rendering its on-demand release sensitive to reactive oxygen species (ROS) levels and pH levels of periodontitis. We seek to analyze the hydrogel’s synergistic effects with MOFs in antibacterial functions, immunomodulation and promotion of bone regeneration in periodontitis. In vivo and in vitro experiment validated the system's efficacy in inhibiting inflammation-related genes and proteins expression to foster periodontal bone regeneration. This dynamic hydrogel system with MOFs, shows promise as a potential therapeutic avenue for addressing the challenges in bone regeneration in periodontitis.
Graphical Abstract
... This pattern of bioactivity was the opposite in the case of the anti-inflammatory cytokine IL-10, which concurrently increased its concentration in the extracellular medium and gene expression. It is important to emphasize that the decision to analyze a single cytokine as a marker of anti-inflammatory activity was based on the existence of a robust body of evidence demonstrating the strategic role of IL-10 in M1/M2 macrophage polarization [44]. In fact, macrophages are versatile cells of the immune system that play a crucial role in host defense, inflammation, and tissue repair. ...
... M1 macrophages involved in wound healing, tissue repair, and resolution of inflammation. Secrete antiinflammatory cytokines (e.g., IL-10) and growth factors, and they help in extracellular matrix remodeling [40,[44][45][46]. Therefore, IL-10 is considered anti-inflammatory and pro-reparative been modulated by S. adstringens extract. ...
Aim: The purpose of this study is to conduct a comprehensive investigation into the modulatory effects of Stryphnodendron adstringens (Mart.; S. adstringens), a Brazilian wound-healing plant, on the expression of inflammatory cytokines. This will be achieved using an in vitro protocol with the commercial macrophage cell line RAW 264.7. Methods: The macrophage inflammatory response was induced by the natural antigen phytohemagglutinin (PHA), with and without supplementation of different concentrations of S. adstringens extract. The effects on cell proliferation rate and the concentration and production of transcripts of pro-inflammatory cytokines interleukin 1β (IL-1β), IL-6, tumor necrosis factor-alpha (TNF-α), and interferon-gamma (IFN-γ), as well as the anti-inflammatory cytokine IL-10, were assessed using spectrophotometric, immunoassay, and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) techniques. Results: S. adstringens extract at all concentrations tested here reduced the cellular proliferation rate of activated macrophages. Extracts at concentrations of 0.49 mg/mL and 0.99 mg/mL decreased the protein and gene expression of pro-inflammatory cytokines, exhibiting the opposite effect concerning IL-10. Conclusions: The findings suggest that the wound-healing action of S. adstringens may encompass differential modulation of inflammation associated with tissue injury.
... These products all together bring out the aggravation of inflammation and absorption of alveolar bone [12,13]. To the delight, the transformation of macrophages from M1 towards M2 can alleviate the inflammation state attributed to the production of transforming growth factor-β (TGF-β) and interleukin-10 (IL-10) [14,15]. Hence, appropriate regulation of macrophage polarization, that is, inhibiting M1 and promoting M2, may become a promising strategy for the treatment of periodontitis. ...
Background and objective
Progranulin (PGRN), a multifunctional growth factor, plays indispensable roles in the regulation of cancer, inflammation, metabolic diseases, and neurodegenerative diseases. Nevertheless, its immune regulatory role in periodontitis is insufficiently understood. This study attempts to explore the regulatory effects of PGRN on macrophage polarization in periodontitis microenvironment.
Methods
Immunohistochemical (IHC) and multiplex immunohistochemical (mIHC) stainings were performed to evaluate the expression of macrophage-related markers and PGRN in gingival samples from periodontally healthy subjects and periodontitis subjects. RAW264.7 cells and bone marrow-derived macrophages (BMDMs) were polarized towards M1 or M2 macrophages by the addition of LPS or IL-4, respectively, and were treated with or without PGRN. Real-time fluorescence quantitative PCR (qRT-PCR), immunofluorescence staining (IF), enzyme-linked immunosorbent assay (ELISA), and flow cytometry were used to determine the expressions of M1 and M2 macrophage-related markers. Co-immunoprecipitation was performed to detect the interaction between PGRN and tumor necrosis factor receptor 2 (TNFR2). Neutralizing antibody was used to block TNFR2 to confirm the role of TNFR2 in PGRN-mediated macrophage polarization.
Results
The IHC and mIHC staining of human gingival slices showed a significant accumulation of macrophages in the microenvironment of periodontitis, with increased expressions of both M1 and M2 macrophage markers. Meanwhile, PGRN was widely expressed in the gingival tissue of periodontitis and co-expressed mainly with M2 macrophages. In vitro experiments showed that in RAW264.7 cells and BMDMs, M1 markers (CD86, TNF-α, iNOS, and IL-6) substantially decreased and M2 markers (CD206, IL-10, and Arg-1) significantly increased when PGRN was applied to LPS-stimulated macrophages relatively to LPS stimulation alone. Besides, PGRN synergistically promoted IL-4-induced M2 markers expression, such as CD206, IL-10, and Arg1. In addition, the co-immunoprecipitation result showed the direct interaction of PGRN with TNFR2. mIHC staining further revealed the co-localization of PGRN and TNFR2 on M2 macrophages (CD206+). Blocking TNFR2 inhibited the regulation role of PGRN on macrophage M2 polarization.
Conclusions
In summary, PGRN promotes macrophage M2 polarization through binding to TNFR2 in both pro- and anti-inflammatory periodontal microenvironments.
... IL10, enriched in M2-EVs, is the messenger of osteogenesis promotion and osteoclastic inhibition, mediating the dual treatment of inflammation and osteolysis in periodontitis mice. 208 Interestingly, inflammation-stimulated osteoclastderived exosomes (iOC-Exos) have a negative feedback role in promoting osteogenic activity. The iOC-Exos targeted ephrinA2/ EphA2 in the osteoblast membrane and then delivered the lncRNA LIOCE to stabilize the osteogenic transcription factor osterix to promote bone formation. ...
Osteoimmunity is an interactive schema by which organisms maintain bone homeostasis. It permeates bone remodeling in healthy or diseased states, such as osseointegration of an oral implant material–alveolar bone socket or inflammatory osteolysis at the plaque-oral tissue–implant material interface. Once the self-mobilized osteoimmune system is insufficient to resist the spread of infection or inflammation caused by progressive periodontitis, smoking, or diabetes, peri-implant bone homeostasis will be tilted toward inflammatory osteolysis, as evidenced by an inflammatory response, osteoblast suppression, and osteoclast hyperactivity. Therefore, in addition to etiological treatment, harnessing osteoimmunity to enhance bone homeostasis stability and tissue anti-inflammatory capacity has also become a therapeutic approach for peri-implantitis. Here, we extract therapeutic targets in terms of cellular, protein, epigenetic modification, ribonucleic acid (RNA), and podosome-related osteoimmune mechanisms in inflammatory osteolysis, summarize the existing bioactive materials, implant surface modification, extracellular vesicles and other bioengineering techniques using osteoimmunity in the treatment of inflammatory bone loss, and look at potential targets for harnessing osteoimmunotherapy in peri-implantitis.
... 43,44 Chen et al. reported that M2-Exos could upregulate the cytokine IL-10 in BMSCs and BMderived macrophages by delivering exosomal IL-10 mRNA to improve alveolar resorption. 45 Kim macrophages in wound healing. 13 In addition, M2-EVs showed better bone-targeting capacity than BMSC-EVs, as evidenced by the high contrast biodistribution of M2-EVs compared with BMSC-EVs in vivo fluorescence images obtained at 12 h after tail vein injection. ...
... Inflammatory macrophages increase pro-inflammatory cytokines and suppress osteoblast differentiation of bone marrow mesenchymal stem cells and PDLSCs by releasing exosomes [19,20]. In addition, M2-exos impede bone marrow-derived macrophage osteoclast formation [21]. However, the effects of M2-exos on osteoclastogenesis of mononuclear macrophages remain unknown. ...
Background: Periodontitis leads to tooth loss, which is associated with bone loss due to osteoclast differentiation. Exosomes play a key role in periodontitis. M2-polarized macrophages exhibit anti-inflammatory activity. This study aimed to explore whether M2 macrophages released exosomes (M2-exos) regulated osteoclastogenesis and the mechanisms. Methods: After isolating M2-exos and identifying them, they were treated with the RANKL-induced raw264.7 cells. Osteoclast differentiation was assessed using tartrate resistant acid phosphatase staining assay and quantitative real-time PCR (qPCR). The underlying mechanisms of M2-exos were evaluated using qPCR and western blotting. Results: The results indicated that M2-exos suppressed osteoclast differentiation induced by RANKL. CSF2 was highly expressed in M2 macrophages, and knockdown of CSF2 further enhanced the inhibitory effects of M2-exos on osteoclast differentiation. CSF2 positively regulated TNF-α signaling, which inhibition also enhanced the role of M2-exos. Conclusion: M2-exos inhibited RANKL-induced osteoclast differentiation by downregulating the CSF2/TNF-α axis. The findings provide theoretical support for the application of macrophage exosomes in the treatment of periodontitis
... With intervention by M2-Exos, the expression levels of miR-690, IRS-1 and TAZ in the signaling pathway increased, thus enhancing the effect of the pathway, in which TAZ drives osteogenic differentiation and inhibits adipogenic differentiation by interacting with PPARγ and Runx2 [98], while IRS-1 is able to increase the expression of TAZ [99]. In addition, M2-Exos can also target and inhibit the expression of salt-inducible kinase 2 and 3 (SIK2 and SIK3) [93] or promote the expression of multiple transcription factors, proteins, or hormones in the body, such as RUNX-2, Col-292, ALP, OCN and IL-10 to promote osteogenic differentiation [94][95][96]. Due to the functions of M2-Exos in promoting bone formation, researchers have combined stromal cell-derived factor-1α (SDF-1α) and M2 macrophagederived exosomes (M2D-Exos) with a hyaluronic acid (HA)-based hydrogel precursor solution to synthesize an injectable hydrogel. This hydrogel promotes the migration and proliferation of BMSCs and human umbilical vein endothelial cells (HUVECs), thereby promoting osteogenesis and angiogenesis in vivo and in vitro, which is beneficial for promoting fracture healing [100]. ...
Accumulating evidence indicates that exosomes help to regulate bone homeostasis. The roles of bone-derived exosomes have been well-described; however, recent studies have shown that some non-bone-derived exosomes have better bone targeting ability than bone-derived exosomes and that their performance as a drug delivery vehicle for regulating bone homeostasis may be better than that of bone-derived exosomes, and the sources of non-bone-derived exosomes are more extensive and can thus be better for clinical needs. Here, we sort non-bone-derived exosomes and describe their composition and biogenesis. Their roles and specific mechanisms in bone homeostasis and bone-related diseases are also discussed. Furthermore, we reveal obstacles to current research and future challenges in the practical application of exosomes, and we provide potential strategies for more effective application of exosomes for the regulation of bone homeostasis and the treatment of bone-related diseases.
Video Abstract
Supplementary Information
The online version contains supplementary material available at 10.1186/s12964-023-01431-7.
... Previous studies have shown that M2-exos increase pro-inflammatory cytokines and suppress osteoblast differentiation of bone marrow mesenchymal stem cells and PDLSCs [27,28]. In addition, Chen et al. [29] have reported that M2-exos impede bone marrow-derived macrophage osteoclast formation via the IL-10/IL-10R pathway, thereby reducing alveolar bone resorption. However, the effects of M2-exos on osteoclastogenesis of mononuclear macrophages remain unknown. ...
Background
Osteoclast-mediated bone resorption cause bone loss in several bone diseases. Exosomes have been reported to regulate osteoclast differentiation. M2-polarized macrophages exhibit anti-inflammatory activity. This study aimed to explore the effect of exosomes from M2 polarized macrophages (M2-exos) on osteoclastogenesis and molecular mechanisms.
Methods
M2-exos were isolated from IL-4-induced Raw264.7 cells (M2 macrophages) and used to treat osteoclasts (RANKL-induced Raw264.7 cells). Osteoclast differentiation was visualized using tartrate resistant acid phosphatase staining. Quantitative real-time PCR (qPCR) was conducted to measure the levels of osteoclastogenesis-related genes. The underlying mechanisms of M2-exos were evaluated using qPCR and western blotting.
Results
M2-exos suppressed osteoclast differentiation induced by RANKL. Additionally, CSF2 was highly expressed in M2 macrophages, and knockdown of CSF2 further enhanced the effects of M2-exos on osteoclast differentiation. Moreover, CSF2 positively regulated TNF-α signaling, which inhibition promoted differentiation of M2-exo-treated osteoclasts.
Conclusion
M2-exos inhibited RANKL-induced osteoclast differentiation by downregulating the CSF2 expression through inactivating the TNF-α signaling, suggesting the potential application of exosomes in bone disease therapy.
... After co-culture, the BMDM cells were collected for subsequent experiments. 30 ...
Spinal cord injury (SCI) is a significant cause of disability worldwide, with limited treatment options. This study investigated the potential of bone marrow-derived mesenchymal stem cells (BMSCs) modified with XIST lentiviral vector to modulate macrophage polarization and affect neural stem cell (NSC) microenvironment reconstruction following SCI. Bioinformatics analysis revealed that MID1 might be crucial for BMSCs’ treatment of SCI. XIST overexpression enriched Zmynd8 to the promoter region of MID1 and inhibited MID1 transcription, which promoted macrophage M2 polarization. In vitro experiments showed that BMSCs-XIST promoted NSC proliferation, migration, differentiation, and axonal growth by inducing macrophage M2 polarization, suppressing inflammation, and accelerating the re-establishment of the homeostatic microenvironment of NSCs. In vivo, animal experiments confirmed that BMSCs-XIST significantly alleviated SCI by promoting NSC differentiation and axon formation in the injured area. The study demonstrated the potential of XIST-overexpressing BMSCs for treating SCI by regulating macrophage polarization and homeostasis of the NSC microenvironment. These findings provide new insights into the development of stem cell-based therapies for SCI.
