Following the fate of murine epidermal stem cells in a syngeneic dermal equivalent in vivo

Role of peroxiredoxin2 downregulation in recurrent miscarriage through regulation of trophoblast proliferation and apoptosis

Peroxiredoxin (Prdx) 2 is an antioxidant protein that utilizes its redox-sensitive cysteine groups to reduce hydrogen peroxide molecules and protect cells against oxidative damage from reactive oxygen species (ROS). However, its function in trophoblasts at the maternal-fetal interface has not been clarified yet. In this study, significantly lower Prdx2 expression was found in the first-trimester villous cytotrophoblasts of patients with recurrent miscarriage (RM) than in cytotrophoblasts from healthy controls. Further, Prdx2 knockdown inhibited proliferation and increased apoptosis of trophoblast cells. The reason for this may be an increase in the level of cellular ROS after knockdown of Prdx2, which may subsequently lead to an increase in the expression of phosphorylated p53 (p-p53) and p38-MAPK/p21. Prdx2 knockdown also impaired the fusion of BeWo cells induced by forskolin. Bioinformatics analysis identified a c-Myc-binding site in the Prdx2 promoter region, and chromatin immunoprecipitation verified that c-Myc directly bound to a site in this locus. Suppression and overexpression of c-Myc resulted in reduction and increase of Prdx2 expression respectively. Furthermore, we demonstrated that c-Myc was downregulated in the first-trimester cytotrophoblasts of patients with RM, and its downregulation is also related with inhibited cell proliferation, increased apoptosis, as well as upregulated p21 expression and p-p53/p53 ratio. Our findings indicate that Prdx2 might have an important role in the regulation of trophoblast proliferation and apoptosis during early pregnancy, and that its expression is mediated by c-Myc. Thus, these two proteins may be involved in the pathogenesis of RM and may represent potential therapeutic targets.

Inferior ectopic bone formation of mesenchymal stromal cells from adipose tissue compared to bone marrow: rescue by chondrogenic pre-induction

Human mesenchymal stromal cells derived from bone marrow (BMSC) and adipose tissue (ATSC) represent a valuable source of progenitor cells for cell therapy and tissue engineering. While ectopic bone formation is a standard activity of human BMSC on calcium phosphate ceramics, the bone formation capacity of human ATSC has so far been unclear. The objectives of this study were to assess the therapeutic potency of ATSC for bone formation in an ectopic mouse model and determine molecular differences by standardized comparison with BMSC. Although ATSC contained less CD146(+) cells, exhibited better proliferation and displayed similar alkaline phosphatase activity upon osteogenic in vitro differentiation, cells did not develop into bone-depositing osteoblasts on β-TCP after 8weeks in vivo. Additionally, ATSC expressed less BMP-2, BMP-4, VEGF, angiopoietin and IL-6 and more adiponectin mRNA, altogether suggesting insufficient osteochondral commitment and reduced proangiogenic activity. Chondrogenic pre-induction of ATSC/β-TCP constructs with TGF-β and BMP-6 initiated ectopic bone formation in >75% of samples. Both chondrogenic pre-induction and the osteoconductive microenvironment of β-TCP were necessary for ectopic bone formation by ATSC pointing towards a need for inductive conditions/biomaterials to make this more easily accessible cell source attractive for future applications in bone regeneration.