The TRAF6-TXNIP-NLRP3 signaling axis regulates LPS-induced pyroptosis in glomerular podocytes.

This study investigated the role of TNF receptor associated factor 6 (TRAF6) in glomerular podocyte pyroptosis. An in vitro LN cell model was established by treating mouse glomerular podocyte MPC5 cells with 100 ng/ml LPS for 12 h. Concurrently, LN cells were treated with TRAF6 knockdown and TXNIP overexpression or NLRP3 activation (Nigericin). MRL/lpr mice were treated with adenovirus vector expressing sh-TRAF6 for in vivo validation. LPS treatment decreased cell viability, increased cell death, elevated Desmin mRNA, malondialdehyde, TRAF6, TXNIP, interleukin (IL)-1β, and IL-18, reduced Nephrin and Podocin mRNA (podocyte markers), superoxide dismutase, and glutathione levels, enhanced cell pyroptosis and lactate dehydrogenase concentration, and activated the NLRP3 inflammasome pathway. TRAF6 knockdown suppressed LPS-stimulated podocyte damage, oxidative stress, and pyroptosis. TRAF6 interacted with TXNIP at the protein level, and TRAF6 increased TXNIP protein expression. The protective functions of TRAF6 silencing on MPC5 cells were counteracted upon TXNIP overexpression or NLRP3 activation. In vivo, TRAF6 knockdown regulated the TXNIP/NLRP3 inflammasome pathway to alleviate renal tissue pathological changes and fibrosis in LN mice. In conclusion, TRAF6 activates the NLRP3 inflammasome pathway through regulating TXNIP, thereby accelerating LPS-induced oxidative stress, pyroptosis, and damage to glomerular podocytes. Hence, TRAF6 may be a promising therapeutic target for LN.