Abstract
Previously, we have reported that ginsenoside Rg3 has typical activities for neuroprotection and Aβ42 clearance by modulating microglia. In this study, we determined the pivotal role of ginsenoside Rg3 in microglia and neuronal cells. In human microglia, Rg3 and its stereoisomers significantly restored inflammatory M1 to normal M0 state and promoted M2 activation by up-regulating acute cytokines such as interleukin-10 and Arginase 1. Moreover, scavenger receptor type A (SRA) was significantly elevated in the presence of ginsenoside Rg3 and 20(S)-Rg3. This indicated that ginsenoside Rg3 could play a crucial role in Aβ uptake and clearance under activated M2 state. We also observed that soluble amyloid precursor protein-alpha (sAPPα) and ADAM10 levels were increased in APP swe-transfected Nuro-2a neuronal cells, whereas sAPPβ was not processed, suggesting that ginsenoside Rg3 was involved in non-amyloidogenic processing. In immunocytochemistry, SRA and a disintegrin and metalloproteinase 10 (desintegrin and metalloproteinase-containing protein 10, ADAM10) were coincidently upregulated in the presence of ginsenoside Rg3 and its stereoisomers compared to those in normal control. Taken together, these results suggested that ginsenoside Rg3 could boost acute activation of microglia, promote Aβ uptake, and elevate the sAPPα processing under activated M2 state. Although in vivo studies need to be performed, it is certain that ginsenoside Rg3 is highly involved in ameliorating the pathogenesis of neurodegeneration and can be a promising candidate for treating Alzheimer's disease as a new therapeutic intervention.
Full text
