Therapeutic Potential of Adipose-Derived SSEA-3-Positive Muse Cells for Treating Diabetic Skin Ulcers

Abstract

Stage-specific embryonic antigen-3 (SSEA-3)-positive multipotent mesenchymal cells (multilineage differentiating stress-enduring [Muse] cells) were isolated from cultured human adipose tissue-derived stem/stromal cells (hASCs) and characterized, and their therapeutic potential for treating diabetic skin ulcers was evaluated. Cultured hASCs were separated using magnetic-activated cell sorting into positive and negative fractions, a SSEA-3+ cell-enriched fraction (Muse-rich) and the remaining fraction (Muse-poor). Muse-rich hASCs showed upregulated and downregulated pluripotency and cell proliferation genes, respectively, compared with Muse-poor hASCs. These cells also released higher amounts of certain growth factors, particularly under hypoxic conditions, compared with Muse-poor cells. Skin ulcers were generated in severe combined immunodeficiency (SCID) mice with type 1 diabetes, which showed delayed wound healing compared with nondiabetic SCID mice. Treatment with Muse-rich cells significantly accelerated wound healing compared with treatment with Muse-poor cells. Transplanted cells were integrated into the regenerated dermis as vascular endothelial cells and other cells. However, they were not detected in the surrounding intact regions. Thus, the selected population of ASCs has greater therapeutic effects to accelerate impaired wound healing associated with type 1 diabetes. These cells can be achieved in large amounts with minimal morbidity and could be a practical tool for a variety of stem cell-depleted or ischemic conditions of various organs and tissues.

Multilineage-differentiating stress-enduring (Muse)-like cells exist in synovial tissue

“…Muse cells were originally identified as cells that are resistant to long-term trypsin incubation and are known as cells that are double positive for the pluripotent surface marker, stage-specific embryonic antigen-3 (SSEA-3), and CD105, and that have the capacity for self-renewal and triploblastic differentiation from a single cell [6]. The applicability of Muse cells for regenerative treatments has been suggested in disease models of liver damage, stroke, skin ulcers related to diabetes mellitus, and osteochondral defects [9], [10], [11], [12].…”

The secretome of MUSE cells contains factors that may play a role in regulation of stemness, apoptosis and immunomodulation

“…Other than differentiation ability, they are reported to exert tissue repair effect by replenishment of lost cell types by spontaneous differentiation after homing into damaged site; they spontaneously differentiated into dermal and epidermal cells to repair skin ulcer of diabetes mellitus model. 11 In stroke model, they spontaneously differentiated into neuronal cells and participated in reconstruction of pyramidal tract, and in hepatectomy model, intravenously injected Muse cells differentiated into liver components after homing. 12,13 Since na€ ıve Muse cells were used in all these studies, Muse cells do not need to be induced into purposive cells prior to transplantation, unlike embryonic stem (ES) and induced pluripotent stem (iPS) cells.…”

Muse Cells: Nontumorigenic Pluripotent Stem Cells Present in Adult Tissues—A Paradigm Shift in Tissue Regeneration and Evolution

“…The Muse-rich fraction integrated into the dermis of the mice, differentiating into vascular endothelial cells, dermal fibroblasts, and keratinocytes. Remarkably, these cells were not detected in functional regions surrounding the skin ulcers [10]. …”

“…The existence of Muse cells has been demonstrated in bone marrow, skin cells, and adipose tissue by seven independent groups worldwide [5, 8, 10–14]. They exist normally in a quiescent state and are activated when exposed to conditions of severe cellular stress both in vitro and in vivo [5, 7–9, 14].…”

“…They migrate to and integrate into damaged tissues to replenish cells and restore tissue function with high efficiency by single intravenous injection, as demonstrated in different animal disease models (e.g., fulminant hepatitis, muscle degeneration, skin ulcers, and brain stroke) [8–10, 16–18]. …”