title: Induction of Cell Death by Betulinic Acid through Induction of Apoptosis and Inhibition of Autophagic Flux in Microglia BV-2 Cells.
abstract: Betulinic acid (BA), a natural pentacyclic triterpene found in many medicinal plants is known to have various biological activity including tumor suppression and anti-inflammatory effects. In this study, the cell-death induction effect of BA was investigated in BV-2 microglia cells. BA was cytotoxic to BV-2 cells with IC₅₀ of approximately 2.0 µM. Treatment of BA resulted in a dose-dependent chromosomal DNA degradation, suggesting that these cells underwent apoptosis. Flow cytometric analysis further confirmed that BA-treated BV-2 cells showed hypodiploid DNA content. BA treatment triggered apoptosis by decreasing Bcl-2 levels, activation of capase-3 protease and cleavage of PARP. In addition, BA treatment induced the accumulation of p62 and the increase in conversion of LC3-I to LC3-II, which are important autophagic flux monitoring markers. The increase in LC3-II indicates that BA treatment induced autophagosome formation, however, accumulation of p62 represents that the downstream autophagy pathway is blocked. It is demonstrated that BA induced cell death of BV-2 cells by inducing apoptosis and inhibiting autophagic flux. These data may provide important new information towards understanding the mechanisms by which BA induce cell death in microglia BV-2 cells.
authors.affiliation: Department of Life and Nanopharmaceutical Sciences, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea.
authors.forename: Jeongbin
authors.initials: J
authors.lastname: Seo
authors.affiliation: Department of Life and Nanopharmaceutical Sciences, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea.
authors.forename: Juneyoung
authors.initials: J
authors.lastname: Jung
authors.affiliation: Department of Life and Nanopharmaceutical Sciences, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea.
authors.forename: Dae Sik
authors.initials: DS
authors.lastname: Jang
authors.affiliation: Department of Oral Biochemistry and Molecular Biology, School of Dentistry, Kyung Hee University, Seoul 02447, Republic of Korea.
authors.forename: Joungmok
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Life and Nanopharmaceutical Sciences, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea.|Department of Oral Biochemistry and Molecular Biology, School of Dentistry, Kyung Hee University, Seoul 02447, Republic of Korea.
authors.forename: Jeong Hee
authors.initials: JH
authors.lastname: Kim
keywords: Apoptosis; Autophagy; Betulinic acid; Microglia BV-2 cell