Partial reduction of interleukin-33 signaling improves senescence and renal injury in diabetic nephropathy.

Diabetic nephropathy (DN) is a frequent and costly complication of diabetes with limited understandings of mechanisms and therapies. Emerging evidence points to the important roles of interleukin-33 (IL-33) in acute kidney injury, yet its contribution to DN is still unclear. We here found a ubiquitous increase of IL-33 and its receptor (ST2) in murine models and patients with DN. Surprisingly, both IL-33 and ST2 knockdown aggravated renal lesions in DN, while overexpression of IL-33 also exacerbated the condition. Further population-based analyses revealed a positive correlation of IL-33 expression with renal dysfunction in DN patients. Individuals with high IL-33 expression-related polygenic risk score had a higher DN risk. These findings confirmed the harmful effects of IL-33 on DN. Conversely, endogenous and exogenous partial reduction of IL-33 signaling conferred renoprotective effects in vivo and in vitro. Mechanistically, IL-33 induced senescence by regulating cell cycle factors in HK-2 cells, and accordingly senescence led to renal cell damage through the secretion of senescence-related secretory phenotype (SASP) including IL-33 and prostaglandins. Together, elevated IL-33 accelerates cellular senescence to drive DN possibly by SASP production, while a partial blockage improves renal injury and senescence. Our findings pinpoint a possible and new avenue for DN interventions.