A Dual Soluble Epoxide Hydrolase Inhibitor/PPAR‐γ Agonist Prevents Renal Fibrosis in Mouse Unilateral Ureteral Obstruction Model

Abstract

Chronic kidney disease (CKD) progresses to end‐stage renal disease and renal fibrosis is a major contributor to CKD progression. We developed a novel dual soluble epoxide hydrolase (sEH) inhibitor‐PPAR‐γ agonist (sEHi/PPAR‐γ), RB394. The objective for this investigation was to determine the ability for RB394 to protect the kidney from fibrosis in a mouse unilateral ureteral obstruction (UUO) model. Efficacy for RB394 is compared to an sEH inhibitor (sEHi), a PPAR‐γ agonist rosiglitazone (Rosi), or their combination. Male C57/BL6 mice underwent a sham or UUO surgical procedure and were grouped (n=6/group) as Sham‐Vehicle, UUO‐Vehicle, UUO‐RB394, UUO‐sEHi, UUO‐Rosi, and UUO‐sEHI+Rosi. Vehicle, RB394 (10mg/kg/d), sEHi (3mg/kg/d), Rosi (10mg/kg/d) or sEHI+Rosi combination was administrated in drinking water for 10 days following UUO induction. Kidneys were collected for mRNA expression, histopathological, and immunohistological analysis. Kidney histopathology in UUO mice revealed marked renal fibrosis with an 8‐fold higher kidney collagen positive area compared to Sham group (P<0.05). RB394 or sEHI+Rosi combination significantly prevented development of kidney collagen positive area by 40% in UUO mice (P<0.05). Fibrotic marker α‐smooth muscle actin (α‐SMA) immunopositive kidney area was 7‐fold higher in UUO compared to Sham group, and all treatments except sEHi prevented the increase in renal α‐SMA levels in UUO by 50–70% compared to vehicle (P<0.05). In UUO mice, renal mRNA expressions of the fibrotic markers α‐SMA, fibronectin, collagen 1α (Col1α), Snail1, Twist, and TGF‐β1 were 4–40‐fold higher compared to Sham group. Interestingly, only RB394 markedly prevented renal mRNA expression of the fibrotic markers and TGF‐β1 (by 50–60%, P<0.05). However, Col1α was prevented by RB394 or sEHI+Rosi combination (by 45 and 50%, respectively). UUO mice also had marked renal oxidative stress with 2–16‐fold higher renal mRNA expression for several oxidative stress markers (NOX1, gp91phox, p47phox, and p22phox) compared to Sham group mice (P<0.05). All treatments prevented renal oxidative stress in UUO mice and prevented renal mRNA expression of the oxidative markers by 20–70% compared to vehicle (P<0.05). Overall, our results demonstrate that a novel dual acting molecule, RB394 that simultaneously inhibits sEH and activates PPAR‐γ prevents renal fibrosis development in a superior manner by preventing renal inflammation and oxidative stress.Support or Funding InformationNational Institute of Health (NIH) grant (DK103616) and Dr. Ralph and Marian Falk Medical Research Trust Bank of America, N.A., Trustee grant to JDI; Deutsche Forschungsgemeinschaft (Sachbeihilfe PR 1405/2‐2, Heisenberg‐Professur PR 1405/4‐1 and SFB 1039 Teilprojekt A07) to EPThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.