Background: Kidneys from all donor sources are highly sensitive to ischemia-reperfusion injury (IRI). However, grafts donated after cardiac death (DCD) sustain an increased incidence of primary non-function and reduced graft function. IRI is the result of inflammatory responses initiated by Toll-like receptors (TLRs). Depends on the availability of ligands, one or more TLR may be necessary to cause inflammatory damage to this tissue. However, TLR4 is most probably involved in reacting to IRI because majority of DAMPs derived from necrotic tissues (HSP & HMGB1) bind to TLR4. The main objective of the present study was to clarify the role of TLR4 in renal IRI and to determine the effects of CLI95 (TLR4 inhibitor) and CORM401 (anti-inflammatory agent) in ex vivo and in vivo animal models of IRI.Methods: TLR expression in bone marrow derived dendritic cells (DCs) and macrophages were observed by qRT-PCR & Western blot. IL6, TNFα, & IL10) and DC maturation markers (CD11c, MHCII, CD80, & CD86) were measured by ELISA & flow cytometry. IRI was generated by removing the right kidney in B6 mice followed by pedicle clamping of left kidney for 1h at 37⁰C. After 24h, clamp released, IRI damage was scored (H&E, TUNEL) & renal function (blood creatinine, urea) was analyzed. Kidney damage was measured by ELISA (KIM-1 & NGAL). Finally signaling pathway related to TLR4-mediated attenuation of inflammation was studied by microarray gene chip analysis, qRT-PCR, and Western blot. Results: IRI-kidney showed significant upregulation of TLR4. TLR4 ligand produced higher levels of IL6 & TNF-α in DCs. However, DCs pre-treated with CLI95 showed significant reduction of IL6 and TNF-α. Microarray analysis revealed that CORM-401 modulates expression of DC maturation markers (CD80, CD83, & CD86) and inflammatory markers. In contrast, expression of key anti-inflammatory proteins (Regnase1, TRIB1) was significantly increased by CORM-401. Importantly, CORM401 treatment of IRI-inflicted animals reduced the kidney IRI injury (ATN: 20% vs. 60%). An improved kidney function was also resulted in CORM401 treatment (Creatinine 75+/-55 vs. 214+/- 39 mmol/L) Conclusion: TLR4 on DCs and macrophages promote the inflammatory reaction subsequent to kidney IRI. CLI95 and CORM401 have potential to protect kidney from IRI damage and improve kidney function.

CITATION INFORMATION: Luke P, Cepinskas G, Alharbi H, Haig A, Bhattacharjee R. Immunosuppressive Actions of CLI95 and CORM401 on TLR4 in Renal Ischemia Reperfusion Injury. Am J Transplant. 2016;16 (suppl 3).

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