Gintonin stimulates autophagic flux in primary cortical astrocytes

다국어 초록 (Multilingual Abstract)

Background: Gintonin (GT), a novel ginseng-derived exogenous ligand of lysophosphatidic acid (LPA)receptors, has been shown to induce cell proliferation and migration in the hippocampus, regulatecalcium-dependent ion channels in the astrocytes, and reduce b-amyloid plaque in the brain. However,whether GT influences autophagy in cortical astrocytes is not yet investigated.
Methods: We examined the effect of GT on autophagy in primary cortical astrocytes using immunoblotand immunocytochemistry assays. Suppression of specific proteins was performed via siRNA. LC3 punctawas determined using confocal microscopy.
Results: GT strongly upregulated autophagy marker LC3 by a concentration- as well as time-dependentmanner via G proteinecoupled LPA receptors. GT-induced autophagy was further confirmed by theformation of LC3 puncta. Interestingly, on pretreatment with an mammalian target of rapamycin (mTOR)inhibitor, rapamycin, GT further enhanced LC3-II and LC3 puncta expression. However, GT-inducedautophagy was significantly attenuated by inhibition of autophagy by 3-methyladenine and knockdownBeclin-1, Atg5, and Atg7 gene expression. Importantly, when pretreated with a lysosomotropicagent, E-64d/peps A or bafilomycin A1, GT significantly increased the levels of LC3-II along with theformation of LC3 puncta. In addition, GT treatment enhanced autophagic flux, which led to an increase inlysosome-associated membrane protein 1 and degradation of ubiquitinated p62/SQSTM1.
Conclusion: GT induces autophagy via mTOR-mediated pathway and elevates autophagic flux. This studydemonstrates that GT can be used as an autophagy-inducing agent in cortical astrocytes.

참고문헌 (Reference)

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