HDAC6 inhibition attenuates renal injury by reducing IL-1β secretion and RIP kinase mediated necroptosis in acute oxalate nephropathy

• Expression of HDAC6 is upregulated in macrophages stimulated with calcium oxalates crystals. • HDAC6 inhibition regulates tubulin mediated lysosomal secretion of IL-1β without effecting IL-1β synthesis and maturation in stimulated macrophages. • HDAC6 inhibitor, TSA ameliorates calcium oxalate crystal induced tubular cell injury in in-vitro. • Treatment with selective HDAC6 inhibitor attenuates renal injury by reducing of IL-1β expression and RIP kinase mediated necroptosis in mouse model of acute oxalate nephropathy. Pathogenesis of acute kidney injury is driven by necro-inflammation, which is comprised of IL-1β mediated inflammation and RIP-1 mediated tubular necroptosis. HDAC6 is reported to regulate both inflammation and cell death. In the present study, we explored the role of HDAC6 in the lysosomal exocytosis of IL-1β and RIP-1 mediated necroptosis in the context of oxalate nephropathy. Raw 264.7 macrophages and NRK52E stimulated with oxalate crystals and LPS with or without HDAC6 inhibitor for in vitro experiments. Acute oxalate nephropathy was induced in C57BL/6 mice by injecting sodium oxalate (75 mg/kg). For the drug intervention study, Tubastain A (TSA) was given an hour before injection of sodium oxalate. Mice were sacrificed 24 hrs after the oxalate injection, blood and kidney were harvested. Blood samples were analyzed for BUN and IL-1β levels. Renal tissues were analyzed for histology, immunohistochemistry, RNA, and protein expression. HDAC6 and IL-1β upregulated in crystal stimulated macrophages and acute oxalate nephropathy. Pre-treatment of macrophages with TSA reduced IL-1β in supernatant without affecting the expression of pro-IL-1β and mature IL-1β in cell lysate. The effect of TSA on IL-1β secretion was influenced by tubulin acetylation. Renal epithelial cell NRK52E stimulated with crystals showed upregulation of necroptosis pathway markers and concentration-dependent cell death. TSA inhibited RIP-1, RIP3, and MLKL expression along with p-MLKL in stimulated epithelial cells. TSA treatment of oxalate nephropathy mice showed decreased inflammation and tubular cell death by regulating IL-1β and necroptosis and reduced renal injury. This study highlights the role of HDAC6 in regulating the tubulin-mediated secretion of IL-1β and RIP kinase mediated necroptosis in acute oxalate nephropathy.