Withaferin A induces apoptosis and inhibits adipogenesis in 3T3 L1 adipocytes
Withaferin A (WA) a highly oxygenated steroidal lactone that is found in the medicinal plant Withania somnifera (also called ashwagandha) has been reported to have anti tumor, anti angiogenesis, and pro apoptotic activity. We investigated the effects of WA on viability, apoptosis and adipogenesis in 3T3 L1 adipocytes. Pre and post confluent preadipocytes and mature adipocytes were treated with WA (1 25 mM) up to 24 hrs. Viability and apoptosis were measured by CellTiter Blue(r) Cell Viability Assay and single strand DNA ELISA Assay, respectively. WA decreased viability and induced apoptosis in all stages of cells. Induction of apoptosis by WA in mature adipocytes was mediated by increased ERK1/2 phosphorylation and altered Bax and Bcl2 protein expression. The effect of WA on adipogenesis was examined by Adipo Red Assay after treating with WA (0.1 1 mM) during the differentiation period. WA decreased lipid accumulation in a dose dependent manner and decreased the expression of peroxisome proliferator activated receptor g, CCAAT/enhancer binding protein a and adipocyte fatty acid binding protein. The effects on apoptosis and lipid accumulation were also confirmed with Hoechst staining and Oil Red O staining, respectively. These results show that WA acts on adipocytes to reduce cell viability and adipogenesis and also induce apoptosis.
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