116 Degradation of TRPML1 in Neurons Reduces Neuron Survival in Transient Global Cerebral Ischemia

Abstract

Postcardiac arrest syndrome yields poor neurological outcomes, but the mechanisms underlying this condition remains poorly understood. Autophagy plays an important role in neuronal apoptosis induced by ischemia. However, whether autophagy is involved in neuron apoptosis induced by cardiac arrest has been less studied. This study found that TRPML1 participates in cerebral ischemic reperfusion injury. Primary neurons were isolated and treated with the vehicle, ML-SA1, MG-132, DEVD, calpeptin, as well as infected with the recombinant lentivirus TRPML1 overexpression vector in vitro. Cell viability was measured by the MTT assay, LC3 and cleaved-caspase3 was also measured. ML-SA1 was delivered intracerebroventricularly in tBCCAO model. Protein expression levels were determined by Western blot. Neurological deficit score was evaluated after TGI and TTC staining was analyzed for the detection of neuronal damage. Our findings suggested that TRPML1 was downregulated in vivo and in vitro ischemic reperfusion model, Additionally, TRPML1 overexpression or treatment with the ML-SA1 attenuated the autophagy and apoptosis in primary neurons. Moreover, in the tBCCAO mice, administration of ML-SA1 ameliorated neurological dysfunction. Taken together, our study provides evidence that TRPML1 participates in delayed neuronal damage after TGI. In addition, our data demonstrate that ML-SA1 pretreatment attenuates neuron injury in vivo and in vitro. These protective effects result from enhancing autophagy, the inhibition of apoptosis and protein ubiquitination. Thus, the regulation of TRPML1 could be a novel strategy for preventing and treating ischemic reperfusion brain injury.View Large Image Figure ViewerDownload Hi-res image Download (PPT)View Large Image Figure ViewerDownload Hi-res image Download (PPT)View Large Image Figure ViewerDownload Hi-res image Download (PPT)