No abstract

High viability and further adipogenic differentiation of adipose-derived stem cells (ADSCs) are fundamental for engraftment and growth of the transplanted adipose tissue. It has been demonstrated that extracellular matrix (ECM) regulates cell proliferation and differentiation by interacting with ERK1/2 signalling pathway. In this study, we prepared autologous decellularized extracellular matrix (d-ECM) and explored its effect on the proliferation and adipogenic ability of ADSCs in low serum culture. We found that 2% foetal bovine serum (FBS) in growth medium inhibited cell viability and DNA replication, and decreased mRNA and protein levels of PPARγ and C/EPBα compared with 10% FBS. Correspondingly, after 14-days adipogenic induction, cells cultured in 2% FBS possessed lower efficiency of adipogenesis and expressed less adipocyte differentiation markers ADIPOQ and aP2. On the contrary, the d-ECM-coated substrate continuously promoted the expression of PPARγ, and regulated the phosphorylation of ERK1/2 in different manners during differentiation. Pretreatment with ERK1/2 inhibitor PD98059 neutralized the effects of d-ECM, which suggested d-ECM might regulate the adipogenesis of ADSCs through ERK1/2-PPARγ pathway. In addition, d-ECM was revealed to regulate the transcription and expression of stemness-associated genes, such as OCT4, NANOG and SOX2, in the undifferentiated ADSCs, which might be related to the initiation of differentiation.

Curcumin is getting more and more attention in wound healing and scar prevention because of its wide range of pharmacological effects, such as anti-inflammation, antioxidant and anti-fibrosis. The activity of fibroblasts suffering from oxidative stress is reduced, affecting wound repair. In this study, we investigated whether curcumin treatment (10 μM, 24 h) had protective effects on human dermal fibroblasts (HDFs) exposed to hydrogen peroxide (H2O2, 300 μM, 12 h). We found that curcumin alleviated H2O2-induced accumulation of reactive oxygen species (ROS, the fold change relative to the untreated control was 1.75 (SD ± 0.21) vs. 5.23 (SD ± 0.51), p < 0.001) and improved the expression and activities of antioxidant enzymes superoxide dismutase 1 (SOD1, 66.61 U (SD ± 7.47) vs. 46.39 U (SD ± 6.82) /10 6 cells, p < 0.05) and catalase (CAT, 9.77 U (SD ± 1.82) vs. 4.61 U (SD ± 0.94) /10 6 cells, p < 0.01), accompanied with increased cell proliferation and migration but decreased senescence. In addition, we found that curcumin reduced the inhibition of autophagy by H2O2, as manifested in the increased autophagic vacuoles (p < 0.05) and higher expression of autophagy-related proteins including PI3KC3 (p < 0.001), LC3-II (p < 0.001) and Beclin1 (p < 0.01). However, intracellular redox status deteriorated again and curcumin’s protection effects were partially canceled after autophagy was inhibited by 3-MA pretreatment. These data suggest that rescue of HDFs from oxidative damage by curcumin may related to the regulation of autophagy levels and ROS generation.