Morg1 heterozygous mice are protected from acute renal ischemia-reperfusion injury

Renal ischemia and reperfusion injury leads to acute renal failure when proinflammatory and apoptotic processes in the kidney are activated. The increase in hypoxia-inducible transcription factor-[alpha] (HIF-[alpha]), an important transcription factor for several genes, can attenuate ischemic renal injury. We recently identified a novel WD-repeat protein designated Morg 1 (MAPK organizer 1) that interacts with prolyl hydroxylase 3 (PHD3), an important enzyme involved in the regulation of HIF-1[alpha] and HIF-2[alpha] expression. While homozygous Morg1 -/- mice are embryonic lethal, heterozygous Morg1 +/- mice have a normal phenotype. We show here that Morg1 +/- were partially protected from renal ischemia-reperfusion injury compared with wild-type Morg1 +/+ animals. Morg1 +/- mice compared with wild-type animals revealed a stronger increase in HIF-1[alpha] and HIF-2[alpha] expression in the ischemic-reperfused kidney associated with enhanced serum erythropoietin levels. However, no significant expression of HIF-1[alpha] and HIF-2[alpha] was found in nonischemic kidneys without any difference between Morg1 +/- and Morg1 +/+ mice. Ischemic kidneys of Morg1 +/- mice expressed more erythropoietin mRNA than ischemic kidneys from wild-type animals. Renal ischemia in Morg1 +/- mice resulted in a decrease in renal inflammation and reduction of proinflammatory cytokines (MCP-1, IP-10, MIP-2) compared with wild-type mice. Furthermore, there was significantly less apoptosis and tubular damage in Morg1 +/- kidneys after ischemia-reperfusion, and this was also reflected in significantly improved renal function compared with wild-type. Thus Morg1 may be a novel therapeutic target to limit renal injury after ischemia-reperfusion. hypoxia; HIF-1[alpha]; HIF-2[alpha]; renal inflammation; chemokine expression; ischemic renal failure doi: 10.1152/ajprenal.00204.2009.