Secretory profiles and wound healing effects of human amniotic fluid-derived mesenchymal stem cells.

Recent evidence shows that amniotic fluid (AF) contains multiple cell types derived from the developing fetus, and may represent a novel source of stem cells for cell therapy. In this study, we examined the paracrine factors released by human amniotic fluid-derived mesenchymal stem cells (AF-MSCs) and their ability to accelerate the wound-healing process by stimulating proliferation and migration of dermal fibroblasts. AF-MSCs expressed the typical MSC marker proteins CD13, CD29, and CD44 and differentiated into adipocytes, osteoblasts, and chondrocytes when exposed to the appropriate differentiation media. In addition, AF-MSC-conditioned media (AF-MSC-CM) significantly enhanced proliferation of dermal fibroblasts. Antibody-based protein array and enzyme-linked immunosorbent assay (ELISA) indicated that AF-MSC-CM contains various cytokines and chemokines that are known to be important in normal wound healing, including IL-8, IL-6, TGF-beta, TNFRI, VEGF, and EGF. Application of AF-MSC-CM significantly enhanced wound healing by dermal fibroblasts via the TGF-beta/SMAD2 pathway. Levels of p-SMAD2 were increased by AF-MSC-CM, and both the increase in p-SMAD2 and migration of dermal fibroblasts were blocked by inhibiting the TGF-beta/SMAD2 pathway. Moreover, in a mouse excisional wound model, AF-MSC-CM accelerated wound healing. These data provide the first evidence of the potential for AF-MSC-CM in the treatment of skin wounds.

Isolation and characterization of multipotent human keloid-derived mesenchymal-like stem cells.

In this study, we report the isolation and characterization of a population of multipotent keloid-derived mesenchymal-like stem cells (KMLSCs) from keloid scalp tissues. These KMLSCs expressed the typical mesenchymal stem cell marker proteins CD13, CD29, CD44, CD90, fibronectin, and vimentin when they were cultured in serum-containing medium and when subsequent exposure to various differentiation media resulted in their differentiation into adipocytes, osteoblasts, chondrocytes, smooth muscle cells, and angiogenic endothelial cells. When KMLSCs were cultured in neural stem culture conditions (i.e., in the presence of epidermal growth factor and fibroblast growth factor 2 in substrate-free conditions), they produced large numbers of neurospheres containing nestin-, CD133-, and SOX2-positive cells that expressed neural-crest stem cell markers. Subsequent exposure of these cells to different differentiation conditions resulted in cells that expressed neuronal cell-, astrocyte-, oligodendrocyte-, or Schwann cell-specific markers. Our study suggests that KMLSCs may be an alternative adult stem cell resource for regenerative tissue repair and auto-transplantation.

Induction of neural stem cell-like cells (NSCLCs) from mouse astrocytes by Bmi1.

Recently, Bmi1 was shown to control the proliferation and self-renewal of neural stem cells (NSCs). In this study, we demonstrated the induction of NSC-like cells (NSCLCs) from mouse astrocytes by Bmi1 under NSC culture conditions. These NSCLCs exhibited the morphology and growth properties of NSCs, and expressed NSC marker genes, including nestin, CD133, and Sox2. In vitro differentiation of NSCLCs resulted in differentiated cell populations containing astrocytes, neurons, and oligodendrocytes. Following treatment with histone deacetylase inhibitors (trichostatin A and valproic acid), the potential of NSCLCs for proliferation, dedifferentiation, and self-renewal was significantly inhibited. Our data indicate that multipotent NSCLCs can be generated directly from astrocytes by the addition of Bmi1.