Dihydrolipoic acid inhibits lysosomal rupture and NLRP3 through lysosome-associated membrane Protein-1/ Calcium/Calmodulin-Dependent Protein Kinase II/TAK1 pathways after subarachnoid hemorrhage in rat

Abstract

Background and Purpose-The NLRP3 (nucleotide binding and oligomerization domain-like receptor family pyrin domaincontaining 3) inflammasome is a crucial component of the inflammatory response in early brain injury after subarachnoid hemorrhage (SAH). In this study, we investigated a role of dihydrolipoic acid (DHLA) in lysosomal rupture, NLRP3 activation, and determined the underlying pathway. Methods-SAH was induced by endovascular perforation in male Sprague-Dawley rats. DHLA was administered intraperitoneally 1 hour after SAH. Small interfering RNA for lysosome-associated membrane protein-1 and CaMKIIα (calcium/calmodulin-dependent protein kinase II α) was administered through intracerebroventricular 48 hours before SAH induction. SAH grade evaluation, short- and long-term neurological function testing, Western blot, and immunofluorescence staining experiments were performed. Results-DHLA treatment increased the expression of lysosome-associated membrane protein-1 and decreased phosphorylated CaMKIIα and NLRP3 inflammasome, thereby alleviating neurological deficits after SAH. Lysosomeassociated membrane protein-1 small interfering RNA abolished the neuroprotective effects of DHLA and increased the level of phosphorylated CaMKIIα, p-TAK1 (phosphorylated transforming growth factor-β-activated kinase), p-JNK (phosphorylated c-Jun-N-terminal kinase), and NLRP3 inflammasome. CaMKIIα small interfering RNA downregulated the expression of p-TAK1, p-JNK, and NLRP3 and improved the neurobehavior after SAH. Conclusions-DHLA treatment improved neurofunction and alleviated inflammation through the lysosome-associated membrane protein-1/CaMKII/TAK1 pathway in early brain injury after SAH. DHLA may provide a promising treatment to alleviate early brain injury after SAH.