Melatonin Synergizes With Mesenchymal Stromal Cells Attenuates Chronic Allograft Vasculopathy

Improved therapeutic effects on vascular intimal hyperplasia by mesenchymal stem cells expressing MIR155HG that function as a ceRNA for microRNA-205

Coronary artery bypass grafting (CABG) is an effective treatment for coronary heart disease, with vascular transplantation as the key procedure. Intimal hyperplasia (IH) gradually leads to vascular stenosis, seriously affecting the curative effect of CABG. Mesenchymal stem cells (MSCs) were used to alleviate IH, but the effect was not satisfactory. This work aimed to investigate whether lncRNA MIR155HG could improve the efficacy of MSCs in the treatment of IH and to elucidate the role of the competing endogenous RNA (ceRNA). The effect of MIR155HG on MSCs function was investigated, while the proteins involved were assessed. IH was detected by HE and Van Gieson staining. miRNAs as the target of lncRNA were selected by bioinformatics analysis. qRT-PCR and dual-luciferase reporter assay were performed to verify the binding sites of lncRNA-miRNA. The apoptosis, Elisa and tube formation assay revealed the effect of ceRNA on the endothelial protection of MIR155HG-MSCs. We observed that MIR155HG improved the effect of MSCs on IH by promoting viability and migration. MIR155HG worked as a sponge for miR-205. MIR155HG/miR-205 significantly improved the function of MSCs, avoiding apoptosis and inducing angiogenesis. The improved therapeutic effects of MSCs on IH might be due to the ceRNA role of MIR155HG/miR-205.

Toward transplantation tolerance with adipose tissue-derived therapeutics

Solid organ and composite tissue allotransplanation have been widely applied to treat end-stage organ failure and massive tissue defects, respectively. Currently there are a lot of research endeavors focusing on induction of transplantation tolerance, to relieve the burden derived from long-term immunosuppressant uptake. The mesenchymal stromal cells (MSCs) have been demonstrated with potent immunomodulatory capacities and applied as promising cellular therapeutics to promote allograft survival and induce tolerance. As a rich source of adult MSCs, adipose tissue provides additional advantages of easy accessibility and good safety profile. In recent years, the stromal vascular fraction (SVF) isolated from adipose tissues following enzymatic or mechanical processing without in vitro culture and expansion has demonstrated immunomodulatory and proangiogenic properties. Furthermore, the secretome of AD-MSCs has been utilized in transplantation field as a potential "cell-free" therapeutics. This article reviews recent studies that employ these adipose-derived therapeutics, including AD-MSCs, SVF, and secretome, in various aspects of organ and tissue allotransplantation. Most reports validate their efficacies in prolonging allograft survival. Specifically, the SVF and secretome have performed well for graft preservation and pretreatment, potentially through their proangiogenic and antioxidative capacities. In contrast, AD-MSCs were suitable for peri-transplantation immunosuppression. The proper combination of AD-MSCs, lymphodepletion and conventional immunosuppressants could consistently induce donor-specific tolerance to vascularized composite allotransplants (VCA). For each type of transplantation, optimizing the choice of therapeutics, timing, dose, and frequency of administration may be required. Future progress in the application of adipose-derived therapeutics to induce transplantation tolerance will be further benefited by continued research into their mechanisms of action and the development of standardized protocols for isolation methodologies, cell culture, and efficacy evaluation.

IL-37 overexpression promotes endometrial regenerative cell-mediated inhibition of cardiac allograft rejection

BACKGROUND

Endometrial regenerative cells (ERCs) play an important role in attenuation of acute allograft rejection, while their effects are limited. IL-37, a newly discovered immunoregulatory cytokine of the IL-1 family, can regulate both innate and adaptive immunity. Whether IL-37 overexpression can enhance the therapeutic effects of ERCs in inhibition of acute cardiac allograft rejection remains unknown and will be explored in this study.

METHODS

C57BL/6 mice recipients receiving BALB/c mouse heterotopic heart allografts were randomly divided into the phosphate-buffered saline (untreated), ERC treated, negative lentiviral control ERC (NC-ERC) treated, and IL-37 overexpressing ERC (IL-37-ERC) treated groups. Graft pathological changes were assessed by H&E staining. The intra-graft cell infiltration and splenic immune cell populations were analyzed by immunohistochemistry and flow cytometry, respectively. The stimulatory property of recipient DCs was tested by an MLR assay. Furthermore, serum cytokine profiles of recipients were measured by ELISA assay.

RESULTS

Mice treated with IL-37-ERCs achieved significantly prolonged allograft survival compared with the ERC-treated group. Compared with all the other control groups, IL-37-ERC-treated group showed mitigated inflammatory response, a significant increase in tolerogenic dendritic cells (Tol-DCs), regulatory T cells (Tregs) in the grafts and spleens, while a reduction of Th1 and Th17 cell population. Additionally, there was a significant upregulation of immunoregulatory IL-10, while a reduction of IFN-γ, IL-17A, IL-12 was detected in the sera of IL-37-ERC-treated recipients.

CONCLUSION

IL-37 overexpression can promote the therapeutic effects of ERCs to inhibit acute allograft rejection and further prolong graft survival. This study suggests that gene-modified ERCs overexpressing IL-37 may pave the way for novel therapeutic options in the field of transplantation.