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Background: Mesenchymal stem cell (MSC) therapy has been shown to be a promising option for liver fibrosis treatment. However, critical factors affecting the efficacy of MSC therapy for liver fibrosis remain unknown. Follistatin-like 1 (FSTL1), a TGF-β-induced matricellular protein, is documented as an intrinsic regulator of proliferation and differentiation in MSCs. In the present study, we characterized the potential role of FSTL1 in MSC-based anti-fibrotic therapy and further elucidated the mechanisms underlying its action., Methods: Human umbilical cord-derived MSCs were characterized by flow cytometry. FSTL1 low MSCs were achieved by FSTL1 siRNA. Migration capacity was evaluated by wound-healing and transwell assay. A murine liver fibrotic model was created by carbon tetrachloride (CCl 4 ) injection, while control MSCs or FSTL1 low MSC were transplanted via intravenous injection 12 weeks post CCl 4 injection. Histopathology, liver function, fibrosis degree, and inflammation were analysed thereafter. Inflammatory cell infiltration was evaluated by flow cytometry after hepatic nonparenchymal cell isolation. An MSC-macrophage co-culture system was constructed to further confirm the role of FSTL1 in the immunosuppressive capacity of MSCs. RNA sequencing was used to screen target genes of FSTL1., Results: FSTL1 low MSCs had comparable gene expression for surface markers to wildtype but limited differentiation and migration capacity. FSTL1 low MSCs failed to alleviate CCl 4 -induced hepatic fibrosis in a mouse model. Our data indicated that FSTL1 is essential for the immunosuppressive action of MSCs on inflammatory macrophages during liver fibrotic therapy. FSTL1 silencing attenuated this capacity by inhibiting the downstream JAK/STAT1/IDO pathway., Conclusions: Our data suggest that FSTL1 facilitates the immunosuppression of MSCs on macrophages and that guarantee the anti-fibrotic effect of MSCs in liver fibrosis., (© 2022. The Author(s).)

Background: Despite emerging evidence on the therapeutic potential of mesenchymal stem cells (MSCs) for liver fibrosis, the underlying mechanisms remain unclear. At present, MSC-derived exosomes (MSC-EXOs) are widely accepted as crucial messengers for intercellular communication. This study aimed to explore the therapeutic effects of MSC-EXOs on liver fibrosis and identify the mechanisms underlying the action of MSC-EXOs., Methods: Carbon tetrachloride was used to induce a liver fibrosis model, which was intravenously administered with MSCs or MSC-EXOs to assess treatment efficacy. The resulting histopathology, fibrosis degree, inflammation and macrophage polarization were analyzed. RAW264.7 and BMDM cells were used to explore the regulatory effects of MSC-EXOs on macrophage polarization. Then, the critical miRNA mediating the therapeutic effects of MSC-EXOs was screened via RNA sequencing and validated experimentally. Furthermore, the target mRNA and downstream signaling pathways were elucidated by luciferase reporter assay, bioinformatics analysis and western blot., Results: MSCs alleviated liver fibrosis largely depended on their secreted exosomes, which were visualized to circulate into liver after transplantation. In addition, MSC-EXOs were found to modulate macrophage phenotype to regulate inflammatory microenvironment in liver and repair the injury. Mechanically, RNA-sequencing illustrates that miR-148a, enriched in the MSC-EXOs, targets Kruppel-like factor 6 (KLF6) to suppress pro-inflammatory macrophages and promote anti-inflammatory macrophages by inhibiting the STAT3 pathway. Administration of miR-148a-enriched MSC-EXOs or miR-148a agomir shows potent ameliorative effects on liver fibrosis., Conclusions: These findings suggest that MSC-EXOs protect against liver fibrosis via delivering miR-148a that regulates intrahepatic macrophage functions through KLF6/STAT3 signaling and provide a potential therapeutic target for liver fibrosis., (© 2022. The Author(s).)

Generating functional hepatocyte-like cells (HLCs) from mesenchymal stem cells (MSCs) is of great urgency for bio-artificial liver support system (BALSS). Previously, we obtained HLCs from human umbilical cord-derived MSCs by overexpressing seven microRNAs (HLC-7) and characterized their liver functions in vitro and in vivo. Here, we aimed to screen out the optimal miRNA candidates for hepatic differentiation. We sequentially removed individual miRNAs from the pool and examined the effect of transfection with remainder using RT-PCR, periodic acid-Schiff (PAS) staining and low-density lipoprotein (LDL) uptake assays and by assessing their function in liver injury models. Surprisingly, miR-30a and miR-1290 were dispensable for hepatic differentiation. The remaining five miRNAs (miR-122, miR-148a, miR-424, miR-542-5p and miR-1246) are essential for this process, because omitting any one from the five-miRNA combination prevented hepatic trans-differentiation. We found that HLCs trans-differentiated from five microRNAs (HLC-5) expressed high level of hepatic markers and functioned similar to hepatocytes. Intravenous transplantation of HLC-5 into nude mice with CCl 4 -induced fulminant liver failure and acute liver injury not only improved serum parameters and their liver histology, but also improved survival rate of mice in severe hepatic failure. These data indicated that HLC-5 functioned similar to HLC-7 in vitro and in vivo, which have been shown to resemble hepatocytes. Instead of using seven-miRNA combination, a simplified five-miRNA combination can be used to obtain functional HLCs in only 7 days. Our study demonstrated an optimized and efficient method for generating functional MSC-derived HLCs that may serve as an attractive cell alternative for BALSS., (© 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.)

Despite the extensive hepatic differentiation potential of human umbilical cord lining-derived mesenchymal stem cells (hUC-MSC), little is known about the molecular mechanisms of hUC-MSC differentiation. At the post-transcriptional level, microRNAs are key players in the control of cell fate determination during differentiation. In this study, we aimed to identify microRNAs involved in the hepatic differentiation of hUC-MSCs. After successfully isolating hUC- MSCs, we induced hepatocyte formation in vitro with growth factors. After 26 days of induction, hUC-MSCs could express hepatocyte-specific genes, synthesize urea and glycogen and uptake low-density lipoprotein. Cellular total RNA from hUC-MSCs and hepatic differentiated hUC-MSCs was collected at 7 time points, including 2 days, 6 days, 10 days, 14 days, 22 days and 26 days, for microRNA microarray analysis. Dynamic microRNA profiles were identified that did not overlap or only partially overlapped with microRNAs reported to be involved in human liver development, hepatocyte regeneration or hepatic differentiation of liver-derived progenitor cells. A total of 61 microRNAs among 1205 human and 144 human viral microRNAs displayed consistent changes and were altered at least 2-fold between hUC-MSCs and hepatic differentiated hUC-MSCs. Among these microRNAs, 25 were over-expressed; this over-expression occurred either gradually or increased sharply and was maintained at a high level. A total of 36 microRNAs were under-expressed, with an expression pattern similar to that of the over-expressed microRNAs. The expression of the altered expressed microRNAs was also confirmed by quantitative reverse-transcription polymerase chain reaction. We also found that microRNAs involved in hepatic differentiation were not enriched in hepatocyte or hepatocellular carcinoma cells and can potentially target liver-enriched transcription factors and genes. The elucidation of the microRNA profile during the hepatic differentiation of hUC-MSCs provides the basis for clarifying the role of microRNAs in hUC-MSC hepatic differentiation and specific microRNA selection for the conversion of hUC-MSCs to hepatocytes.

Objective: To construct the eukaryotic expression vector hypoxia-inducible factor 1alpha-pcDNA(3.1) and to investigate its transfective efficiency into mesenchymal stem cells (MSCs) in vitro and the expression of HIF-1alpha gene in MSCs., Methods: mRNA of Wistar Rats' myocardial cells was extracted, and cDNA was synthesized with Reverse Transcription Kit, HIF-1alpha was amplified by polymerase chain reaction (PCR), and constructed into pcDNA(3.1). Transfected HIF-1alpha-pcDNA(3.1) into MSCs by liposome mediated method. The expression of HIF-1alpha in the cells was detected by Western Blot Analysis and ELISA., Results: Eukaryotic expression vector HIF-1alpha-pcDNA(3.1) was constructed successfully. Analyzed by flow cytometer, The MSCs' surfaces mark were CD44+, SH3(CD73)+, CD34-, CD45- and the CD44+ cells and SH3(CD73)+ cells were 94.7% and 97.3%, respectively, showing the high purity of the cultured MSCs. After inducing, the cultured MSCs can differentiate into osteoblasts and adipocytes successfully. In HIF-1alpha gene transfected MSCs, the expression of HIF-1alpha mRNA and HIF-1alpha protein were both increased obviously., Conclusion: HIF-1alpha was cloned successfully. HIF-1alpha-pcDNA(3.1) can be transfected into MSCs by liposome-mediated method effectively and which resulting stable expression of HIF-1alpha in transfected MSCs.

Background: Mesenchymal stem cells (MSCs) and hematopoietic stem cells (HSCs) have been studied for damaged liver repair; however, the conclusions drawn regarding their homing capacity to the injured liver are conflicting. Besides, the relative utility and synergistic effects of these two cell types on the injured liver remain unclear. Methodology/Principal Findings: MSCs, HSCs and the combination of both cells were obtained from the bone marrow of male mice expressing enhanced green fluorescent protein(EGFP)and injected into the female mice with or without liver fibrosis. The distribution of the stem cells, survival rates, liver function, hepatocyte regeneration, growth factors and cytokines of the recipient mice were analyzed. We found that the liver content of the EGFP-donor cells was significantly higher in the MSCs group than in the HSCs or MSCs+HSCs group. The survival rate for the MSCs group was significantly higher than that of the HSCs or MSCs+HSCs group; all surpassed the control group. After MSC-transplantation, the injured livers were maximally restored, with less collagen than the controls. The fibrotic areas had decreased to a lesser extent in the mice transplanted with HSCs or MSCs+HSCs. Compared with mice in the HSCs group, the mice that received MSCs had better improved liver function. MSCs exhibited more remarkable paracrine effects and immunomodulatory properties on hepatic stellate cells and native hepatocytes in the treatment of the liver pathology. Synergistic actions of MSCs and HSCs were most likely not observed because the stem cells in liver were detected mostly as single cells, and single MSCs are insufficient to provide a beneficial niche for HSCs. Conclusions/Significance: MSCs exhibited a greater homing capability for the injured liver and modulated fibrosis and inflammation more effectively than did HSCs. Synergistic effects of MSCs and HSCs were not observed in liver injury. [ABSTRACT FROM AUTHOR]