Exploring molecular targets and active compounds from buyang huanwu decoction for promoting neurogenesis in post-ischemic stroke treatment

Abstract

Stroke is a leading cause of death and adult disability in human diseases. Recent progress in stem cell biology provides new opportunities for drug discovery to promoting neurogenesis in the adult mammalian brain for therapeutic purposes. With huge amount of unique compounds and long history for treatment of stroke, Traditional Chinese Medicine (TCM) provides vast sources for drug discovery. Buyang Huanwu Decoction (BHD), a classic TCM formula, has been used for treatment of stroke for hundreds of years. However, the underlying mechanisms and its active compounds remain unknown. In this study, we used proteomic approaches to explore the therapeutic principles and molecular targets for promoting neurogenesis in both in vitro cultured neural stem cells and in vivo middle cerebral artery occlusion (MCAO) rat model. Our results revealed that BHD treatment successfully restored neurological functions, reduced cerebral infarction volume and inhibited apoptotic cell death in the MCAO ischemia-reperfused rat brains. Further studies showed that BHD treatment significantly promoted the proliferation and differentiations of neural stem cells (NSCs) in vivo and in vitro. Proteomics experiment revealed that BHD treatment modulated multiple cell signal pathways involved in the process of proliferation and differentiation of NSCs, the formation of axon and neuron network and anti-apoptosis. In particular, we selectively investigated the active compounds within the formula with the properties of regulating the JAK2/STAT3, Notch and MAPK/ERK signal pathways. We screened about 30 single compounds and fractions isolated from BHD and identified an active compound named HQ22 with remarkable effects on promoting the proliferation of NSCs in both in vitro cell experiments and in vivo MCAO ischemia-reperfusion animal model. HQ22 was confirmed to be an EGFR promoter and its neurogenesis-promoting mechanisms were related to activate the EGFR induced MAPK/ERK pathway. In conclusion, BHD is an effective TCM formula for promoting neurogenesis. BHD could actively regulate multiple cellular signaling pathways and finally improve the post-stroke function recovery. The active compounds from BHD have great potentials to be developed into new drug candidates targeting neural stem cells for brain repair in post-stroke treatment.