Local and Remote Effects of Mesenchymal Stem Cell Administration on Skin Wound Regeneration

Immunomodulatory performance of GMP-compliant, clinical-grade mesenchymal stromal cells from four different sources

Inflammatory and autoimmune diseases are among the most challenging disorders for health care professionals that require systemic immune suppression which associates with various side effects. Mesenchymal stromal cells (MSCs) are capable of regulating immune responses, mainly through paracrine effects and cell-cell contact. Since MSCs are advanced therapy medicinal products (ATMPs), they must follow Good Manufacturing Practice (GMP) regulations to ensure their safety and efficacy. In this study, we evaluated the immunomodulatory effects of GMP-compliant clinical grade MSCs obtained from four different sources (bone marrow, adipose tissue, Wharton's Jelly, and decidua tissue) on allogeneic peripheral blood mononuclear cells (PBMCs). Our results revealed that WJ-MSCs were the most successful group in inhibiting PBMC proliferation as confirmed by BrdU analysis. Moreover, WJ-MSCs were the strongest group in enhancing the regulatory T cell population of PBMCs. WJ-MSCs also had the highest secretory profile of prostaglandin E2 (PGE-2), anti-inflammatory cytokine, while interleukin-10 (IL-10) secretion was highest in the DS-MSC group. DS-MSCs also had the lowest secretion of IL-12 and IL-17 inflammatory cytokines. Transcriptome analysis revealed that WJ-MSCs had the lowest expression of IL-6, while DS-MSCs were the most potent group in the expression of immunomodulatory factors such as hepatocyte growth factor (HGF) and transforming growth factor-β (TGF- β). Taken together, our results indicated that GMP-compliant Wharton's Jelly and decidua-derived MSCs showed the best immunomodulatory performance considering paracrine factors.

Mesodermal Derivatives of Pluripotent Stem Cells Route to Scarless Healing

Scar formation during normal tissue regeneration in adults may result in noticeable cosmetic and functional defects and have a significant impact on the quality of life. In contrast, fetal tissues in the mid-gestation period are known to be capable of complete regeneration with the restitution of the initial architecture, organization, and functional activity. Successful treatments that are targeted to minimize scarring can be realized by understanding the cellular and molecular mechanisms of fetal wound regeneration. However, such experiments are limited by the inaccessibility of fetal material for comparable studies. For this reason, the molecular mechanisms of fetal regeneration remain unknown. Mesenchymal stromal cells (MSCs) are central to tissue repair because the molecules they secrete are involved in the regulation of inflammation, angiogenesis, and remodeling of the extracellular matrix. The mesodermal differentiation of human pluripotent stem cells (hPSCs) recapitulates the sequential steps of embryogenesis in vitro and provides the opportunity to generate the isogenic cell models of MSCs corresponding to different stages of human development. Further investigation of the functional activity of cells from stromal differon in a pro-inflammatory microenvironment will procure the molecular tools to better understand the fundamental mechanisms of fetal tissue regeneration. Herein, we review recent advances in the generation of clonal precursors of primitive mesoderm cells and MSCs from hPSCs and discuss critical factors that determine the functional activity of MSCs-like cells in a pro-inflammatory microenvironment in order to identify therapeutic targets for minimizing scarring.

Equilibrium among Inflammatory Factors Determines Human MSC-Mediated Immunosuppressive Effect

Mesenchymal stem cells (MSCs) are thought to be a promising therapeutic agent due to their multiple paracrine and immunomodulatory properties, providing protection from chronic inflammation and promoting tissue repair. MSCs can regulate the balance of pro-inflammatory and anti-inflammatory factors in inflamed tissues, creating a microenvironment necessary for successful healing; however, their interactions with immune cells are still poorly studied. We examined the temporal and spatial changes in gene regulation and the paracrine milieu accompanying the MSC-mediated immunosuppression effect in mixed cultures with activated peripheral blood mononuclear cells (PBMCs). Our data reveal that the peak of suppression of PBMC proliferation was achieved within 48 h following co-culture with MSCs and subsequently did not undergo a significant change. This effect was accompanied by an increase in COX-2 expression and an induction of IDO synthesis in MSCs. At this point, the expression of IL-1, IL-6, IL-8, IFN-γ, MCP-1, and G-CSF was upregulated in co-cultured cells. On the contrary, we observed a decrease in the concentrations of IL-10, IL-13, IL-5, and MIP-1b in co-culture supernatants compared to intact cultures of activated PBMCs. The regulation of IDO, IL-1, IL-6, and G-CSF production was accomplished with the involvement of direct cell-cell contact between MSCs and PBMCs. These findings provide new insights into the use of potential precondition inducers or their combinations to obtain functionally qualified MSCs for more effective treatment of inflammatory diseases.