Dongxue Xu
student
Zhongnan Hospital of Wuhan University,, United States
Disclosure information not submitted.
Title: TIMP2 attenuates inflammatory response in sepsis-induced AKI through the Inhibition of NLRP3.
Introduction: Tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors of matrix metalloproteinases (MMPs). TIMP2 is both expressed and secreted preferentially by cells of tubule origin. The role of TIMP2, both inhibitor and activator of MMPs, remains unclear. Here, we report that TIMP2 inhibits NLRP3 inflammasome activation via a second messenger cyclic adenosine monophosphate (cAMP), which binds to NLRP3 and promotes its ubiquitination and degradation. The renal tubular-specific TIMP2-knockout mice after cecum ligation and puncture (CLP) and LPS treatment showed upregulated cellular inflammasome response when compared with the wildtype (WT) mice, which indicated that TIMP2 is an endogenous regulator of inflammasome activation as a potential target for the treatment of NLRP3 inflammasome-driven AKI.
Objectives: The objective of this project was to elucidate the role of TIMP2 on inflammatory regulation following acute kidney injury (AKI) and the mechanism of TIMP2 function on subsequent inflammasome response following AKI by modulation of Pyroptosis.
Methods: Wild-type C57BL/6 (WT) mice and renal tubular-specific TIMP2-knockout (TIMP2−/−) mice were used in this work. AKI model was established by CLP and intraperitoneal injection of LPS dissolved in 0.9% saline (10mg/kg). Animals were sacrificed on indicated days post-treatment. Kidney tissues and sera were subjected to histological, cellular, and molecular analyses by H&E staining, Western Blot, immunohistochemistry, ELISA, etc. It was statistically significant when p< 0.05 by t-test or ANOVA.
Results: TIMP2−/− mice exhibited more severe kidney injury compared to WT after CLP and LPS treatment. Kidney injury scores of TIMP2−/− mice were also significantly higher than that of WT mice (p< 0.05). Furthermore, the serum levels of IL-1β of TIMP2−/− mice were higher than that of WT post CLP and LPS treatment. TIMP2−/− mice's kidney tissues exhibited more than those of WT mice evidenced by H&E staining, respectively. Moreover, TIMP2−/− mice showed more NLRP3，Caspase1 and GSDMD expression (p< 0.05) compared to WT mice. ELISA analyses demonstrated higher cAMP activity in the kidney of TIMP2−/− mice compared to that of WT mice, suggesting the regulatory role of TIMP in kidney injury after AKI through cAMP signaling.