Search

Diabetic foot disease (DFD) is a major public health concern and is characterized by impaired angiogenesis. Transplantation of endothelial progenitor cell (EPC) holds great potential for treating DFD. However, the poor cell survival of transplant-derived EPCs limits their beneficial effects. Here, we report a preconditioning scheme for the generation of endothelial progenitor-like cells by chemical induction in nutrients deprivation and D-glucose-containing conditions with TGF inhibitor sb431542. The preconditioned endothelial progenitor-like cells (pEPCs) were induced from human umbilical vein endothelial cells (huvecs) and the expression of CD34 was markedly upregulated (༞90%) in pEPCs. Furthermore, pEPCs have the potential to resist pathological environmental stress, which is characterized by their high cell viability, oxidative stress tolerance and enhanced tubulogenesis under simulated DFD conditions. The protective effect of preconditioning in pEPCs is partly achieved by activating the PI3K/AKT pathway to up-regulate the expression of Nrf2 and HIF-1α. Importantly, due to its enhanced retention and angiogenesis, the transplanted pEPCs showed improved therapeutic potential for wound regeneration in diabetic mice. Overall, this study explores a novel preconditioning condition and provides an easy and efficient strategy to obtain pEPCs, which could be an ideal cell source for treating DFD and for endothelialization of tissue-engineered constructs.

Background: Decompensated liver cirrhosis (DLC), a terminal-stage complication of liver disease, is a major cause of morbidity and mortality in patients with hepatopathie. Human umbilical cord mesenchymal stem cell (hUCMSCs) therapy has emerged as a treatment novel alternative for the treatment of DLC. However, optimized therapy protocols and the associated mechanisms are not completely understood. Methods: We constructed a DLC rat model consistent with the typical clinical characteristics combined use of PB and CCL4. By performing dynamic detection of liver morphology and function in rats for 11 weeks, the various disease characteristics of DLC and the therapeutic effect of hUCMSCs on DLC in experimental rats were fully investigated, according to ascites examination, histopathological and related blood biochemical analyses. Flow-cytometry analysis of rat liver, immunofluorescence and RT-qPCR were performed to examine the changes of liver immune microenvironment after hucMSCs treatment. RNA-seq analysis of liver and primary macrophages and hUCMSCs co-culture system in vitro were performed to explore possible signaling pathways. PPARγ antagonist, GW9662, and clodronate liposomes were used to inhibit PPAR activation and pre-exhaustion of macrophages in DLC rats’ liver respectively. Results: We found that changing of the two key issues, the frequency and initial phase of hUCMSCs infusion can affect the efficacy of hUCMSCs and the optimal hUCMSCs treatment schedule is once every week for three weeks at the early-stage of DLC progression, providing the best therapeutic effect in reducing mortality and ascites, and improving liver function in DLC rats. hUCMSCs treatment skewed the macrophage phenotype from M1-type to M2-type through activating PPARγ signaling pathway in liver, which was approved by primary macrophages and hUCMSCs co-culture system in vitro. Both inhibition of PPARγ activation with GW9662 and pre-exhaustion of macrophages in DLC rats’ liver abolished the regulation of hUCMSCs on macrophage polarization, thus attenuating the beneficial effect of hUCMSCs treatment in DLC rats. Conclusions: HUCMSCs treatment on DLC were attributed to the activation of the PPARγ signaling pathway in liver macrophages of DLC rats, which polarizes M1-type macrophages to M2-type, thus inhibiting inflammation and promoting the repair of damaged liver tissue. Our results about different infusion regimens comparison and mechanisms exploration provide a robust theoretical foundation for the future study design of Mesenchymal Stem Cells therapy on DLC.

Background Liver fibrosis (LF) is a common pathological process characterized by the activation of hepatic stellate cells (HSCs) and accumulation of extracellular matrix. Severe LF causes cirrhosis and even liver failure, a major cause of morbidity and mortality worldwide. Transplantation of human placental mesenchymal stem cells (hPMSCs) has been considered as an alternative therapy. However, the underlying mechanisms and the appropriate time window for hPMSC transplantation are not well understood. Methods We established mouse models of CCl4-injured LF and administered hPMSCs at different stages of LF once a week for 2 weeks. The therapeutic effect of hPMSCs on LF was investigated, according to histopathological and blood biochemical analyses. In vitro, the effect of hPMSCs and the secretomes of hPMSCs on the inhibition of activated HSCs was assessed. RNA sequencing (RNA-seq) analysis, real-time PCR array, and western blot were performed to explore possible signaling pathways involved in treatment of LF with hPMSCs. Results hPMSC treatment notably alleviates experimental hepatic fibrosis, restores liver function, and inhibits inflammation. Furthermore, the therapeutic effect of hPMSCs against mild-to-moderate LF was significantly greater than against severe LF. In vitro, we observed that the hPMSCs as well as the secretomes of hPMSCs were able to decrease the activation of HSCs. Mechanistic dissection studies showed that hPMSC treatment downregulated the expression of fibrosis-related genes, and this was accompanied by the upregulation of Caveolin-1 (Cav1) (p < 0.001). This suggested that the amelioration of LF occurred partly due to the restoration of Cav1 expression in activated HSCs. Upregulation of Cav1 can inhibit the TGF-β/Smad signaling pathway, mainly by reducing Smad2 phosphorylation, resulting in the inhibition of activated HSCs, whereas this effect could be abated if Cav1 was silenced in advance by siRNAs. Conclusions Our findings suggest that hPMSCs could provide multifaceted therapeutic benefits for the treatment of LF, and the TGF-β/Cav1 pathway might act as a therapeutic target for hPMSCs in the treatment of LF.