Interplay Between NLRP3 Activation by DENV-2 and Autophagy and Its Impact on Lipid Metabolism in HMEC-1 Cells

Dengue Virus (DENV) induces assembly of the NOD-like receptor (NLR) family pyrin domain containing-3 (NLRP3) inflammasome and autophagy, which are closely interconnected processes playing crucial roles in lipid metabolism and DENV replication. However, the autophagy-NLRP3 activation interplay during DENV infection in human endothelial cells remains incompletely understood. We aimed to elucidate effects of NLRP3 activation on autophagy during DENV-2 infection. We investigated how autophagy-related molecules are altered by NLRP3 inhibition and how this regulation affects lipid metabolism, through the master lipid transcription factors SREBP-1 and 2, which increase the expression of their target lipid-synthesizing genes such as fatty acid synthase (FAS) in a model of microvascular endothelial cells (HMEC-1). We demonstrated a dynamic interplay between inflammasome activity and autophagy in DENV-infected HMEC-1 cells: autophagy increases early during infection and decreases as inflammasome activity increases. NLRP3 inflammasome inhibition affects viral replication. Glyburide (an inflammasome inhibitor) treatment partially inhibited DENV-induced NLRP3 inflammasome activation. Non-structural viral protein expression (NS3 and NS5) and infectious viral-particle formation were significantly reduced. NLRP3 inhibition also downregulated SREBP-1 and SREBP-2 activation. These findings provide new insights into the modulation of the interconnected NLRP3 inflammasome, autophagy, and lipid metabolism pathways, presenting a promising therapeutic strategy for severe clinical forms of dengue.