Berberine Confers Neuroprotective Against Cerebral Ischemic By Regulating PPAR-? Expression

As a traditional drug,Berberine has recently been explored for protection of cerebral ischemic and anti-cancer purposes in several studies.Berberine protects against cerebral ischemia by reducing the neuronal damages caused by reperfusion.PPAR-?,a key transcription factor of many genes in response to ischemia and other type of cellular stress,also plays role of anti-inflammation and anti-apoptosis against cerebral ischemia,which indicating the link between Berberine and PPAR-?.Employ in vivo(mouse,Bilateral carotid artery ligation)and in vitro(C17.2 cell,oxygen-glucose deprivation)model of cerebral ischemia and reperfusion,we studied the mechanism of berberine against ischemia-reperfusion.Based on cell morphology observation and cell survival measurement by the MTT assay,we confirmed neuronal protection of Berberine in the ischemia-reperfusion model.Using qPCR and WB analysis indicated that Berberine regulated PPAR-? regulation in response to OGD,we found that berberine enhanced PPAR-? expression during cerebral ischemia–reperfusion whereas decreased it under normal condition,which indicated the different regulation mechanism between physiology and pathology conditions.Besides,we reported that the effect of Berberine against ischemia is suppressed by the PPAR-? inhibitor GW9662.Thus Berberine regulates PPAR-? expression to play roles against ischemia-reperfusion.It has been reported that ischemia damage had tight connection with hyper-methylation,and methylation enzymes were highly expressed in neuronal system while ischemia induced hyper-methylation.We presented here that berberine decreased the overall global methylation during ischemia by reducing the expression of methylation enzymes Dnmt1 and Dnmt3 a in ischemia-reperfusion.Considering the different regulation of berberine to PPAR-? expression before and after ischemia–reperfusion,employing BSP PCR and promoter reporter,we revealed that Berberine regulates PPAR-? expression by reduce the hyper-methylation caused by ischemia-reperfusion.In conclusion,Berberine manipulates the methylation of PPAR-? against ischemia-reperfusion.Finally,we studied the anti-cancer activities of berberine,which have been reported extensively in various cancer cell lines.However,the minimal inhibitory concentrations of BBR varied greatly among different cell lines and very few studies have been devoted to elucidate this aspect.In this study,we employed three cancer cell lines,HepG2,HeLa and SY5 Y,to compare the transportation and distribution of Berberine.HPLC results demonstrated that Berberine was capable of penetrating all the cell lines whereas the cumulative concentrations were significantly different.HepG2 cells accumulated higher level of BBR for longer duration than the other two cell lines.Molecular docking studies revealed the Berberine binding site on P-glycoprotein 1.In addition,we elucidated that BBR regulated P-gp at both mRNA and protein levels.Berberine induced the transcription and translation of P-gp in HeLa and SY5 Y cells,whereas BBR inhibited P-gp expression in HepG2 cells.Further study showed that Berberine regulates P-gp expression depending on different mechanisms(or affected by different factors)in cell lines.To summarize,our study has revealed several mechanistic aspects of Berberine role against ischemia-reperfusion and anti-cancer activities,and might shed some useful insights into the use of Berberine in the future.