Microvesicles from human adipose stem cells promote wound healing by optimizing cellular functions via AKT and ERK signaling pathways

Abstract

BackgroundHuman adipose stem cells (ASCs) have emerged as a promising treatment paradigm for skin wounds. Recent works demonstrate that the therapeutic effect of stem cells is partially mediated by extracellular vesicles, which comprise exosomes and microvesicles. In this study, we investigate the regenerative effects of isolated microvesicles from ASCs and evaluate the mechanisms how ASC microvesicles promote wound healing.MethodsAdipose stem cell-derived microvesicles (ASC-MVs) were isolated by differential ultracentrifugation, stained by PKH26, and characterized by electron microscopy and dynamic light scattering (DLS). We examined ASC-MV effects on proliferation, migration, and angiogenesis of keratinocytes, fibroblasts, and endothelial cells both in vitro and in vivo. Next, we explored the underlying mechanisms by gene expression analysis and the activation levels of AKT and ERK signaling pathways in all three kinds of cells after ASC-MV stimulation. We then assessed the effect of ASC-MVs on collagen deposition, neovascularization, and re-epithelialization in an in vivo skin injury model.ResultsASC-MVs could be readily internalized by human umbilical vein endothelial cells (HUVECs), HaCAT, and fibroblasts and significantly promoted the proliferation, migration, and angiogenesis of these cells both in vitro and in vivo. The gene expression of proliferative markers (cyclin D1, cyclin D2, cyclin A1, cyclin A2) and growth factors (VEGFA, PDGFA, EGF, FGF2) was significantly upregulated after ASC-MV treatment. Importantly, ASC-MVs stimulated the activation of AKT and ERK signaling pathways in those cells. The local injection of ASC-MVs at wound sites significantly increased the re-epithelialization, collagen deposition, and neovascularization and led to accelerated wound closure.ConclusionsOur data suggest that ASC-MVs can stimulate HUVEC, HaCAT, and fibroblast functions. ASC-MV therapy significantly accelerates wound healing, and the benefits of ASC-MVs may due to the involvement of AKT and ERK signaling pathways. This illustrates the therapeutic potential of ASC-MVs which may become a novel treatment paradigm for cutaneous wound healing.Electronic supplementary materialThe online version of this article (10.1186/s13287-019-1152-x) contains supplementary material, which is available to authorized users.

Extracellular Vesicles Derived From Mesenchymal Stem Cells (MSC) in Regenerative Medicine: Applications in Skin Wound Healing

“…It is involved in numerous cellular processes, like proliferation, migration, and angiogenesis. Thus, the mechanisms of action of the EV derived from the MSC on angiogenesis might be mediated trough the AKT/ERK/STAT-3 signaling pathways (Shabbir et al, 2015;Ren et al, 2019).…”

“…Different studies have been carried out to better understand the mechanisms activating the angiogenesis during CSU healing, after being treated with EV. That includes the involvement of several miRNA and the activation of the AKT, ERK, and STAT-3 signaling pathways (Shabbir et al, 2015;Ding et al, 2019;Ren et al, 2019). Additionally, it has been demonstrated that the EV can also enhance the angiogenesis, through the portmanteau of "Wingless" and "Int-1" called "wingless-related integration site" (Wnt)/b-catenin (or canonical Wnt) pathway .…”

“…The MSC-derived EV increased the skin re-epithelialization in full-thickness cutaneous wounds in animal models (Robson et al, 2001;Zhang et al, 2015aZhang et al, , 2018Li et al, 2017;Tao et al, 2017;Ren et al, 2019;Wang et al, 2019b). However, there are few works analyzing the specific effects of such EV in keratinocytes.…”

Secretome of Adipose Tissue-Derived Stem Cells (ASCs) as a Novel Trend in Chronic Non-Healing Wounds: An Overview of Experimental In Vitro and In Vivo Studies and Methodological Variables

“…The treatment also led to higher levels of type-1 and type-3 collagens by upregulating the PI3K/Akt signaling pathway. A recent article of Ren et al [79] also reported that microvesicles (MVs) derived from ASCs were able to stimulate HUVECs, HaCaT cells, and primary human foreskin fibroblasts due to the activation of the Akt and extracellular signal-regulated kinase (ERK) signaling pathways. In this work, ASCs, previously isolated from subcutaneous fat specimens, were used at passage 2-7 for the collection of microvesicles.…”

Risk factors and complications after body‐contouring surgery and the amount of stromal vascular fraction cells found in subcutaneous tissue

“…1,2 These cells make up for about two-thirds of the CD45-negative cells within the SVF, which is thus representative for the amount of ASCs in the tissue, and there is no difference in cell yield between superficial and deep subcutaneous fat layers. 3 Recent literature suggests that the therapeutic effect of ASCs is partially mediated by the secretion of cytokines, and thus they are able to stimulate local fibroblasts of the wound bed 4,5 to promote wound healing and angiogenesis. 6 Also, in problematic diabetic wounds, ASCs have been shown to accelerate wound healing in animal models 7 via enhanced angiogenesis and immunomodulation.…”