Stavudine Reduces NLRP3-Inflammasome Activation and Upregulates Aβ-Autophagy

Alzheimers disease (AD) is associated with amyloid-beta (A{beta}) deposition and neuroinflammation, possibly driven by activation of the NLRP3 inflammasome. Nucleoside reverse transcriptase inhibitors (NRTI) hamper the assembly of the NLRP3 inflammasome; we analyzed whether stavudine (D4T), a prototypical NRTI, modulates A{beta}-mediated inflammasome activation; because neuroinflammation impairs A{beta} clearance by phagocytes, phagocytosis and autophagy were examined as well. THP-1-derived macrophages were stimulated in vitro with A{beta}42 alone or after LPS priming with/without D4T. NLRP3 and TREM2 expression was analyzed by RT-PCR, phagocytosis and ASC-Speck by AmnisFlowSight, NLRP3-produced cytokines by ELISA, authophagy by P-ELISA evaluation of P-ERK and P-AKT. Results showed that IL1{beta}, IL18 and caspase-1 were increased whereas A{beta}-phagocytosis and TREM2 were reduced in LPS+A{beta}42-stimulated cells. D4T reduced NLRP3 assembly as well as IL18 and caspase-1 production, but not IL1{beta}, phagocytosis, and TREM2. P-AKT expression was augmented and P-ERK was reduced by D4T, suggesting a stimulatory effect on autophagy. D4T reduces NLRP3 inflammasome-associated inflammation, possibly restoring autophagy, in an in vitro model of AD; it will be interesting to verify its possibly beneficial effects in the clinical scenario.