Antioxidants cause rapid expansion of human adipose-derived mesenchymal stem cells via CDK and CDK inhibitor regulation

Abstract

BackgroundAntioxidants have been shown to enhance the proliferation of adipose-derived mesenchymal stem cells (ADMSCs) in vitro, although the detailed mechanism(s) and potential side effects are not fully understood.In this study, human ADMSCs cultured in ImF-A medium supplemented with antioxidants (N-acetyl-l-cysteine and ascorbic acid-2-phosphate) and fibroblast growth factor 2 (FGF-2) were compared with ADMSCs cultured with FGF-2 alone (ImF) or with FGF-2 under 5% pO2 conditions (ImF-H).ResultsDuring log-phase growth, exposure to ImF-A resulted in a higher percentage of ADMSCs in the S phase of the cell cycle and a smaller percentage in G0/G1 phase. This resulted in a significantly reduced cell-doubling time and increased number of cells in the antioxidant-supplemented cultures compared with those supplemented with FGF-2 alone, an approximately 225% higher cell density after 7 days. Western blotting showed that the levels of the CDK inhibitors p21 and p27 decreased after ImF-A treatment, whereas CDK2, CDK4, and CDC2 levels clearly increased. In addition, ImF-A resulted in significant reduction in the expression of CD29, CD90, and CD105, whereas relative telomere length, osteogenesis, adipogenesis, and chondrogenesis were enhanced. The results were similar for ADMSCs treated with antioxidants and those under hypoxic conditions.ConclusionAntioxidant treatment promotes entry of ADMSCs into the S phase by suppressing cyclin-dependent kinase inhibitors and results in rapid cell proliferation similar to that observed under hypoxic conditions.

Avoidance of Maternal Cell Contamination and Overgrowth in Isolating Fetal Chorionic Villi Mesenchymal Stem Cells from Human Term Placenta

“…Several components included in EGM2 medium have been determined to enhance human MSC proliferation, including the well-known bFGF [46,47], and also EGF, IGF-1, and ascorbic acid [48][49][50][51][52][53]. It would be of interest to determine in future which factors are critical for fetal CV-MSC proliferation.…”

Metabolic regulation of mesenchymal stem cell in expansion and therapeutic application

“…Abnormal level of oxidative stress and insufficient antioxidant enzyme activity is the major factor affecting the genetic stability of MSCs and hinders cell growth. Antioxidants such as N ‐acetyl‐ L ‐cysteine (NAC), Trolox, and selenite are demonstrated to reduce oxidative stress level, enhance proliferation and differentiation of MSCs . For example, the supplement of NAC (2.5 mM or 5 mM) in rat BMSC culture medium significantly enhanced alkaline phosphatase activity and mineralized matrix formation together with upregulation of bone‐related gene markers .…”

An overview on different strategies for the stemness maintenance of MSCs

“…The mechanisms by which antioxidants prompt cell proliferation are like those participate in hypoxia, but the in vitro culture environment of antioxidant complemented medium under normoxic situations may be further steady than hypoxic situations. Therefore, a mixture of antioxidants and FGF-2 under normoxic conditions may supply a simple and quick technique for in vitro expansion of both ADMSCs and BMMSCs (Sun et al 2013).…”