Mesenchymal stem cell-derived exosomes promote tissue repair injury in rats with liver trauma by regulating gut microbiota and metabolism

OBJECTIVE

The effects of mesenchymal stem cells (MSCs) and MSC-derived exosomes (MSC-exos) on serum metabolites and intestinal microbiota in rats after liver trauma were discussed.

METHODS

Adult Wistar Albino rats were assigned into control, model (liver trauma), MSCs, and MSC-exos groups (n = 6). The study examined changes in the inflammatory environment in liver tissues were analyzed by histological examination and analysis of macrophage phenotypes. Alterations in serum metabolites were determined by untargeted metabonomics, and gut microbiota composition was characterized by 16S rDNA sequencing. Correlations between specific gut microbiota, metabolites, and inflammatory response were calculated using Spearman correlation analysis.

RESULTS

Rats with liver trauma after MSCs and MSC-exos treatment exhibited attenuated inflammatory infiltration and necrosis in liver tissues. MSCs and MSC-exos treatment reduced the proportion of M1 macrophages, accompanied by a decrease in inducible nitric oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-α) levels. Furthermore, MSCs and MSC-exos treatment expanded the proportion of M2 macrophages, accompanied by an increase in arginase-1 (Arg-1) and interleukin-10 (IL-10) levels. The beneficial effects of MSC-exo treatment on rats with liver trauma were superior to those of MSC treatment. The composition and abundance of the gut microbiota and metabolites were altered in pathological rats, whereas MSC and MSC-exo intervention partially restored specific gut microbiota and metabolite alterations. At the phylum level, alterations in Bacteroidota, Proteobacteria, and Verrucomicrobiota were observed after MSC and MSC-exo intervention. At the genus level, Intestinimonas, Alistipes, Aerococcus, Faecalibaculum, and Lachnospiraceae_ND3007_group were the main differential microbiota. 6-Methylnicotinamide, N-Methylnicotinamide, Glutathione, oxidized, ISOBUTYRATE, ASCORBATE, EICOSAPENTAENOATE, GLYCEROL 3-PHOSPHATE, and Ascorbate radical were selected as important differential metabolites. There was a clear correlation between Ascorbate, Intestinimonas/Faecalibaculum and inflammatory cytokines.

CONCLUSION

MSC-exos promoted the repair of tissue damage in rats with liver trauma by regulating serum metabolites and intestinal microbiota, providing new insights into how MSC-exos reduced inflammation in rats with liver trauma.

Identification and analysis of MSC-Exo-derived LncRNAs related to the regulation of EMT in hypospadias

OBJECTIVE

This study aims to screen the differentially expressed long non-coding RNAs (DELncRNAs) related to the regulation of epithelial-mesenchymal transition (EMT) in hypospadias in mesenchymal stem cell-derived exosomes (MSC-Exons) and explore the potential mechanism of these lncRNAs for the EMT in hypospadias.

METHODS

In this study, the microarray data related to MSC-Exos and hypospadias were downloaded from Gene Expression Omnibus (GEO). Besides, the lncRNAs highly expressed in MSC-Exos and the differentially expressed mRNAs and lncRNAs in children with hypospadias were screened, respectively. In addition, the lncRNAs enriched in MSC-Exos and differentially expressed lncRNAs in hypospadias were intersected to obtain the final DElncRNAs. Moreover, the co-expression interaction pairs of differentially expressed lncRNAs and mRNAs were analyzed to construct a Competing Endogenous RNA (ceRNA) network. Finally, the candidate lncRNAs in exosomes were subjected to in vitro cell function verification.

RESULTS

In this study, a total of 4 lncRNAs were obtained from the microarray data analysis. Further, a ceRNA regulatory network of MSC-Exo-derived lncRNAs related to the regulation of EMT in hypospadias was constructed, including 4 lncRNAs, 2 mRNAs, and 6 miRNAs. The cell function verification results indicated that the exosomes secreted by MSCs may transport HLA complex group 18 (HCG18) into target cells, which promoted the proliferation, migration, and EMT of these cells.

CONCLUSION

MSC-Exo-derived lncRNA HCG18 can enter target cells, and it may be involved in the regulation of EMT in hypospadias through the ceRNA network.

Mesenchymal Stem Cell-Derived Exosomes Ameliorate Doxorubicin-Induced Cardiotoxicity

Doxorubicin (DOX) is an incessantly used chemotherapeutic drug that can cause detrimental dose-dependent effects such as cardiotoxicity and congestive heart failure. Hence, there is a need to discover innovative therapeutic approaches to counteract DOX-induced cardiotoxicity (DIC). MSC-Exos have shown to reduce apoptosis and cardiac fibrosis and promote cardiomyocyte proliferation in myocardial infracted mice. However, the effect of MSC-Exos on ameliorating DOX-induced pyroptosis has not been investigated. In this current study, H9c2 were first exposed to DOX to stimulate pyroptosis, followed by subsequent treatment with MSC-Exos, with further analysis performed through immunocytochemistry, western blotting, and RT-PCR. Our data depicted that post-treatment with MSC-Exos significantly (p < 0.05) reduced the HMGB1/TLR4 axis, inflammasome formation (NLRP3), pyroptotic markers (caspase-1, IL-1β, and IL-18), and the pyroptotic executioner (GSDMD) in DOX-treated H9c2 cells. In conclusion, our data show that MSC-Exos attenuates inflammation-induced pyroptosis in our in vitro DIC model. Our findings indicate that MSC-Exos may serve as a promising therapeutic intervention for mitigating DIC, as they maintain the therapeutic capabilities of MSCs while circumventing the drawbacks associated with traditional stem cell therapy.

HMOX1-overexpressing mesenchymal stem cell-derived exosomes facilitate diabetic wound healing by promoting angiogenesis and fibroblast function

Many scholars have suggested that exosomes (Exos) can carry active molecules to induce angiogenesis and thus accelerate diabetic wound healing. Heme oxygenase-1 (HO-1) encoded by the gene HMOX1 promotes wound healing in DM by enhancing angiogenesis. Nevertheless, whether HMOX1 regulates wound healing in DM through mesenchymal stem cell-derived exosomes (MSC-Exos) remains to be further explored. The primary isolated- and cultured-cells expressed MSC-specific marker proteins, and had low immunogenicity and multi-differentiation potential, which means that MSCs were successfully isolated in this study. Notably, HO-1 protein expression was significantly higher in Exo-HMOX1 than in Exos, indicating that HMOX1 could be delivered to Exos as an MSCs-secreted protein. After verifying the -Exo structure, fibroblasts, keratinocytes, and human umbilical vein endothelial cells (HUVECs) were incubated with Exo-HMOX1 or Exo, and the findings displayed that Exo-HMOX1 introduction promoted the proliferation and migration of fibroblasts, keratinocytes and the angiogenic ability of HUVECs in vitro study. After establishing diabetic wound model mice, PBS, Exo, and Exo-HMOX1 were subcutaneously injected into multiple sites on the 1st, 3rd, 7th, and 14th day, DM injected with Exo-HMOX1 showed faster wound healing, re-epithelialization, collagen deposition, and angiogenesis than those in PBS and Exo groups in vitro study. In summary, Exo-HMOX1 could enhance the activity of fibroblasts, keratinocytes, and HUVEC, and accelerate wound healing by promoting angiogenesis in DM.

MSC-Exos: Important active factor of bone regeneration

Bone defect and repair is a common but difficult problem in restorative and reconstructive surgery. Bone tissue defects of different sizes caused by different reasons bring functional limitations and cosmetic deformities to patients. Mesenchymal stem cells (MSC), a major hotspot in the field of regeneration in recent years, have been widely used in various studies on bone tissue regeneration. Numerous studies have shown that the bone regenerative effects of MSC can be achieved through exosome-delivered messages. Although its osteogenic mechanism is still unclear, it is clear that MSC-Exos can directly or indirectly support the action of bone regeneration. It can act directly on various cells associated with osteogenesis, or by carrying substances that affect cellular activators or the local internal environment in target cells, or it can achieve activation of the osteogenic framework by binding to materials. Therefore, this review aims to summarize the types and content of effective contents of MSC-Exos in bone regeneration, as well as recent advances in the currently commonly used methods to enable the binding of MSC-Exos to the framework and to conclude that MSC-Exos is effective in promoting osteogenesis.

Mesenchymal Stem Cell-derived Exosomes Affect Macrophage Phenotype: A Cell-free Strategy for the Treatment of Skeletal Muscle Disorders

The process of tissue damage, repair, and regeneration in the skeletal muscle system involves complex inflammatory processes. Factors released in the inflammatory microenvironment can affect the phenotypic changes of macrophages, thereby changing the inflammatory process, making macrophages an important target for tissue repair treatment. Mesenchymal stem cells exert anti-inflammatory effects by regulating immune cells. In particular, exosomes secreted by mesenchymal stem cells have become a new cell-free treatment strategy due to their low tumorigenicity and immunogenicity. This article focuses on the mechanism of the effect of exosomes derived from mesenchymal stem cells on the phenotype of macrophages after skeletal muscle system injury and explores the possible mechanism of macrophages as potential therapeutic targets after tissue injury.