Stavudine Reduces NLRP3 Inflammasome Activation and Modulates Amyloid-β Autophagy

Article type: Research Article

Authors: La Rosa, Francesca^{a; d; *} | Saresella, Marina^{a; d} | Marventano, Ivana^a | Piancone, Federica^{a; d} | Ripamonti, Enrico^a | Al-Daghri, Nasser^b | Bazzini, Chiara^{c; d} | Zoia, Chiara Paola^{c; d} | Conti, Elisa^{c; d} | Ferrarese, Carlo^{c; d; e} | Clerici, Mario^{a; f}

Affiliations: [a] IRCCS Fondazione Don Carlo Gnocchi, Milan, Italy | [b] Chair for Biomarkers of Chronic Diseases, Biochemistry Department, College of Science, King Saud University, Riyadh, Saudi Arabia | [c] Laboratory of Neurobiology, School of Medicine and Surgery, Monza, Italy | [d] Milan Center for Neuroscience, University of Milano-Bicocca, Milan, Italy | [e] Department of Neuroscience, S. Gerardo Hospital, Monza, Italy | [f] Department of Physiopathology and Transplants, University of Milan, Milan, Italy

Correspondence: [*] Correspondence to: Francesca La Rosa, PhD, Laboratory of Molecular Medicine and Biotechnology, Don C. Gnocchi Foundation ONLUS IRCCS, via Capecelatro, 66, 20148 Milano, Italy. Tel.: +39 0240308374; Fax: +39 0240308438; E-mail: flarosa@dongnocchi.it.

Abstract: Background:Alzheimer’s disease (AD) is associated with the accumulation of amyloid-β (Aβ) within senile plaques in the brain and neuroinflammation, possibly driven by the activation of the NLRP3 inflammasome. Nucleoside reverse transcriptase inhibitors (NRTI) hamper the NLRP3 inflammasome assembly. Objective:We utilized an in vitro model reproducing the Aβ-driven inflammation seen in AD to analyze whether stavudine (D4T), a prototypical NRTI, modulates Aβ-mediated inflammasome activation and the ability of macrophages to eliminate Aβ via phagocytosis and autophagy. Methods:THP-1-derived macrophages were stimulated in vitro with Aβ42 or with Aβ42 after LPS-priming in the presence/absence of D4T. NLRP3 and TREM2 expression was analyzed by RT-PCR; phagocytosis, as well as ASC-Speck formation, was analyzed by Amnis FlowSight Imaging; NLRP3-produced cytokines were quantified by ELISA and, finally, autophagy was analyzed by measuring p-ERK1/2, p-AKT, beclin, p70-S6Kinase, and Lamp by ELISA and western blot. Results:IL-1β, IL-18, and caspase-1 were increased whereas Aβ phagocytosis and TREM2 were reduced in LPS+Aβ42-stimulated cells. D4T reduced NLRP3 assembly as well as IL-18 and caspase-1 production, but did not affect IL-1β production and TREM2 expression. Notably, whereas D4T reduced Aβ phagocytosis, Aβ autophagy by macrophages was stimulated by D4T, as witnessed by the down-modulation of ERK1/2 and AKT phosphorylation and the upregulation of beclin, LAMP, and p70-S6K, their downstream targets. Conclusion:In this in vitro model of AD, D4T reduces NLRP3 inflammasome-associated inflammation and stimulates Aβ autophagy by macrophages. It will be interesting to verify the possibly beneficial effects of D4T in the clinical scenario.

Keywords: Alzheimer’s disease, amyloid-β phagocytosis, autophagy, cytokines, D4T, NLRP3-inflammasome

DOI: 10.3233/JAD-181259

Journal: Journal of Alzheimer's Disease, vol. 72, no. 2, pp. 401-412, 2019