P0512SKLB023 ATTENUATED LIPOPOLYSACCHARIDE-INDUCED ACUTE KIDNEY INJURY VIA INHIBITION OF NF-KAPPPAB AND MAPKS PATHWAYS

Abstract

Abstract Background and Aims Excessive nitric oxide (NO) production by the activation of inducible nitric oxide synthase (iNOS) during sepsis was considered to contribute to acute kidney injury (AKI) and selective inhibition of iNOS activity may be a promising strategy for the treatment of sepsis-induced AKI. The novel small molecule compound (Z)-N-(3-Chlorophenyl)-2-(4-((2,4-dioxothiazolidin-5-ylidene) methyl) phenoxy) acet-amide (SKLB023) as a selective iNOS inhibitor was designed, synthesized by our lab and exhibited therapeutic potential in arthritis and non-alcoholic steatohepatitis models with potent anti-inflammatory effects. This study aimed to evaluate whether SKLB023 as a drug candidate could offer renal protective effect against sepsis-induced AKI. Method 21 C57BL6 mice (20-22g, 6-8 weeks old) were randomly divided into three groups: control, model, SKLB023 pretreatment. AKI was induced by a single injection of 10mg/kg LPS, and SKLB023 was orally administrated at the dose of 50 mg/kg for three consecutive days and one hour before LPS injection. All mice were sacrificed 16h after LPS injection and blood and kidney tissues were collected for further evaluation. LPS-induced renal dysfunction was assessed by measurement of blood creatinine and urea nitrogen (BUN) as well as histopathological changes. Moreover, the kidney mRNA and protein expression of neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule 1(KIM-1), newly identified kidney injury markers, were tested by polymerase chain reaction (PCR) and western blot. To explore underlying mechanisms, the renal expression of inflammatory cytokine genes IL-1β, IL-6, mcp-1 and proteins iNOS, COX-2, IL-1β, TNF-α, IL-6, HMGB1 in were measured. The total expression of nuclear factor-kappa B (NF-κB), IκBα and MAPKs proteins (ERK1/2, p38 MAPK) and their corresponding phosphoproteins (p-NF-κB, p-IκBα, p-ERK1/2, p-P38 MAPK) in mice kidneys were subsequently analyzed by western blot. Results 16hours following LPS challenge, mice developed AKI as evidenced by elevated creatinine and BUN levels and corresponding pathological changes. Additionally, kidney expression of NGAL and KIM-1 were remarkably increased after LPS injection. SKLB023 pretreatment, however, alleviated LPS-induced renal dysfunction. Moreover, the excessive production of inflammatory cytokines during sepsis was significantly suppressed by SKLB023. Further observation from PCR and immunoblot results indicated that SKLB023 attenuated the activity of NF-kB and the phosphorylation of ERK1/2 and p38 MAPK in septic AKI mice. Conclusion These data demonstrated that SKLB023 exhibited renoprotective effect in LPS-induced AKI, which was associated with its anti-inflammatory activities by inhibiting the NF-kappaB and MAPK signaling pathways