PARP1 promotes NLRP3 activation via blocking TFEB-mediated autophagy in rotenone-induced neurodegeneration.

Rotenone, a widely used pesticide, causes dopaminergic neurons loss and increase the risk of Parkinson's disease (PD). However, few studies link the role of PARP1 to neuroinflammatory response and autophagy dysfunction in rotenone-induced neurodegeneration. Here, we identified that PARP1 overactivation caused by rotenone led to autophagy dysfunction and NLRP3-mediated inflammation. Further results showed that PARP1 inhibition could reduce NLRP3-mediated inflammation, which was effectively eliminated by TFEB knockdown. Moreover, PARP1 poly(ADP-ribosyl)ated TFEB that reduced autophagy. Of note, PARP1 inhibition could rescue rotenone-induced dopaminergic neurons loss. Overall, our study revealed that PARP1 blocks autophagy through poly (ADP-ribosyl)ating TFEB and inhibited NLRP3 degradation, which suggests that intervention of PARP1-TFEB-NLRP3 signaling can be a new treatment strategy for rotenone-induced neurodegeneration.

p38-TFEB pathways promote microglia activation through inhibiting CMA-mediated NLRP3 degradation in Parkinson's disease.

BACKGROUND: Parkinson's disease (PD) is characterized by degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc), accompanied by accumulation of α-synuclein, chronic neuroinflammation and autophagy dysfunction. Previous studies suggested that misfolded α-synuclein induces the inflammatory response and autophagy dysfunction in microglial cells. The NLRP3 inflammasome signaling pathway plays a crucial role in the neuroinflammatory process in the central nervous system. However, the relationship between autophagy deficiency and NLRP3 activation induced by α-synuclein accumulation is not well understood. METHODS: Through immunoblotting, immunocytochemistry, immunofluorescence, flow cytometry, ELISA and behavioral tests, we investigated the role of p38-TFEB-NLRP3 signaling pathways on neuroinflammation in the α-synuclein A53T PD models. RESULTS: Our results showed that increased protein levels of NLRP3, ASC, and caspase-1 in the α-synuclein A53T PD models. P38 is activated by overexpression of α-synuclein A53T mutant, which inhibited the master transcriptional activator of autophagy TFEB. And we found that NLRP3 was degraded by chaperone-mediated autophagy (CMA) in microglial cells. Furthermore, p38-TFEB pathways inhibited CMA-mediated NLRP3 degradation in Parkinson's disease. Inhibition of p38 had a protective effect on Parkinson's disease model via suppressing the activation of NLRP3 inflammasome pathway. Moreover, both p38 inhibitor SB203580 and NLRP3 inhibitor MCC950 not only prevented neurodegeneration in vivo, but also alleviated movement impairment in α-synuclein A53T-tg mice model of Parkinson's disease. CONCLUSION: Our research reveals p38-TFEB pathways promote microglia activation through inhibiting CMA-mediated NLRP3 degradation in Parkinson's disease, which could be a potential therapeutic strategy for PD. p38-TFEB pathways promote microglia activation through inhibiting CMA-mediated NLRP3 degradation in Parkinson's disease. In this model, p38 activates NLRP3 inflammasome via inhibiting TFEB in microglia. TFEB signaling negatively regulates NLRP3 inflammasome through increasing LAMP2A expression, which binds to NLRP3 and promotes its degradation via chaperone-mediated autophagy (CMA). NLRP3-mediated microglial activation promotes the death of dopaminergic neurons.

Rotenone-Induced Neurodegeneration Is Enabled by a p38-Parkin-ROS Signaling Feedback Loop.

Rotenone, a component of pesticides, is widely used in agriculture and potentially causes Parkinson's disease (PD). However, the regulatory mechanisms of rotenone-induced PD are unclear. Here, we revealed a novel feedback mechanism of p38-Parkin-ROS regulating rotenone-induced PD. Rotenone treatment led to not only the activation of p38 but also Parkin inactivation and reactive oxygen species (ROS) overproduction in SN4741 cells. Meanwhile, p38 activation regulated Parkin phosphorylation at serine 131 to disrupt Parkin-mediated mitophagy. Notably, both p38 inhibition and Parkin overexpression decreased ROS levels. Additionally, the ROS inhibitor N-acetyl-l-cysteine (NAC) inhibited p38 and activated Parkin-mediated mitophagy. Both p38 inhibition and the ROS inhibitor NAC exerted a protective effect by restoring cell death and mitochondrial function in rotenone-induced PD models. Based on these results, the p38-Parkin-ROS signaling pathway is involved in neurodegeneration. This pathway represents a valuable treatment strategy for rotenone-induced PD, and our study provides basic research evidence for the safe use of rotenone in agriculture.