The elucidation of the molecular mechanisms that govern the differentiation and proliferation of human adipose tissue-derived mesenchymal stem cells (hASCs) could improve hASC-based cell therapy. In this study, we examined the roles of microRNA (miRNA)-196a on hASC proliferation and osteogenic differentiation. Lentiviral overexpression of miR-196a decreased hASC proliferation and enhanced osteogenic differentiation, without affecting adipogenic differentiation. Overexpression of miR-196a decreased the protein and mRNA levels of HOXC8, a predicted target of miR-196a. HOXC8 expression was decreased during osteogenic differentiation of hASCs, and this decrease in HOXC8 expression was concomitant with an increase in the level of miR-196a. In contrast, inhibition of miR-196a with 29-O-methyl-antisense RNA increased the protein levels of HOXC8 in treated hASCs and was accompanied by increased proliferation and decreased osteogenic differentiation. The activity of a luciferase construct containing the miR-196a target site from the HOXC8 39UTR was lower in LV-miR196a-infected hASCs than in LV-miLacZ-infected cells. RNA interference-mediated downregulation of HOXC8 in hASCs increased their proliferation and decreased their differentiation into osteogenic cells, without affecting their adipogenic differentiation. Our data indicate that miR-196a plays a role in hASC osteogenic differentiation and proliferation, which may be mediated through its predicted target, HOXC8. This study provides us with a better knowledge of the molecular mechanisms that govern hASC differentiation and proliferation.

Fucoidan is a sulfated polysaccharide purified from brown algae including, Fucus vesiculosus and Fucus vesiculosus and Laminaria japonica. It has a variety of biological effects including antioxidant and antitumor activity. In this study, we investigated the radioprotective effects of fucoidan on normal human newborn foreskin fibroblast cell line HS68. To evaluate the effects of fucoidan, we assayed cell viability in vitro and change of blood cells such as thrombocytes, erythrocytes, leukocytes and hematocrit with radiation. In a viability assay, fucoidan increased dose-dependently the recovery of radiation-induced damage by 8Gy at all tested dose (10, 50 and 100 μg/ml). The survival rate of HS68 cells by pre-treatment with fucoidan was increased by 2 times more than it's compared with untreated cells. Furthermore, fucoidan protected the change of blood cells as follows; the thrombocyte of the irradiated controls had fallen to 35% compared with the initial values, the thrombocyte counts in fucoidan pre-treated group was recovered to 49% at the day 14. The Hematocrit level of fucoidan pre-treated group showed the recovery activity by 72% at the day 14, while hematocrit level of irradiated control without fucoidan fell to 61%. In case of erythrocyte level, the radiated controls was consistently maintained by the end of experiment at the range of 60~70%, on the other hand, the erythrocyte counts of fucoidan pretreated group gently increased the level of erythrocyte at the range of 82~90%. These results may provide valuable and useful information in the field of radio-protection.