Renal and Vascular Effects of the Allosteric Transglutaminase 2 Modulator LDN-27219 in One-Kidney DOCA-Salt Mice

The enzyme transglutaminase 2 (TG2) has an open conformation with transamidase activity which crosslinks matrix proteins contributing to fibrosis development. LDN-27219 promotes the closed conformation of TG2, which can enhance vasodilation, but its effects in renal tissue are unknown. We investigated whether LDN-27219 treatment affects albuminuria and markers of renal fibrosis as well as ex vivo vasodilatation. Male C57BL/6 mice (n = 48) underwent unilateral nephrectomy plus insertion of a deoxycorticosterone acetate pellet (DOCA group) or nephrectomy only (sham group). Both groups were randomized to intraperitoneal treatment with either LDN-27219 (8 mg/kg twice daily) or vehicle for 2 weeks. Urine albumin excretion was evaluated by metabolic cages. Kidney tissue fibrosis markers were assessed by qPCR and Western blotting, while the TG2 conformational state was evaluated using native gel electrophoresis. Collagen staining was performed using Picrosirius red and quantified under circularly polarized light. Mesenteric arteries were mounted in wire myographs for evaluation of vasorelaxation. DOCA mouse developed significant albuminuria (p < 0.001 vs. sham), but neither TG2 mRNA nor protein expression was upregulated in the kidney. However, the relative amount of TG2 in the closed conformation was higher in DOCA mice. LDN-27219 did not affect albuminuria, but LDN-27219-treated DOCA mice showed less urine production and less collagen staining than vehicle-treated DOCA mice. LDN-27219 did not affect TG2 mRNA or TG2 protein expression or mRNA of fibrosis markers. LDN-27219-treated mice had enhanced vasorelaxation to the nitric oxide donor sodium nitroprusside. In conclusion, LDN-27219 treatment in the one-kidney DOCA-salt model did not affect renal TG2 mRNA and protein expression or albuminuria but still exerted beneficial effects in terms of reduced kidney fibrosis and urine production in addition to enhanced vasodilatation.