Department of Biomedicine, Health, Aarhus University, Denmark.
Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
Eur J Pharmacol. 2024 Dec 5;984:177037. doi: 10.1016/j.ejphar.2024.177037. Epub 2024 Oct 5.
Transglutaminase 2 (TG2) is a multifunctional enzyme involved in fibrosis by promoting transforming-growth-factor-β1 and crosslinking of extracellular matrix proteins. These functions are dependent on the open conformation, while the closed state of TG2 can induce vasodilation. We explored the putative protective role of TG2 in its closed state on development of renal fibrosis and blood pressure (BP) regulation.
We studied the unilateral ureteral obstruction (UUO) mouse model treated with LDN27219, which promotes the closed conformation of TG2. Mice were subjected to 7 days UUO or sham operation and treated with vehicle (n = 10), LDN27219 (15 mg/kg/12 h, n = 9) or candesartan (5 mg/kg/day, n = 10) as a clinically comparator. Renal expression of TG2 and pro-fibrotic mediators were evaluated by Western blotting, qPCR and histology, and BP by tail-cuff measurements.
Obstructed kidneys showed increased mRNA and protein expression of fibronectin, collagen 3α1 (Col3α1), α-smooth muscle actin and collagen staining. Despite increased renal TG2 mRNA, protein expression was reduced in all UUO groups, but with increased transamidase activity in the vehicle and candesartan groups. LDN27219 reduced mRNA expression of fibronectin and Col3α1, but their protein expression remained unchanged. In contrast to LDN27219, candesartan lowered BP without affecting expression of pro-fibrotic biomarkers.
Renal TG2 mRNA and protein expression levels seem dissociated, with transamidase activity being increased. LDN27219 influences kidney pro-fibrotic markers at the mRNA level and attenuates transamidase activity but without affecting collagen content or BP. Our findings suggest that TG2 in its closed conformation has anti-fibrotic effects at the molecular level.
转谷氨酰胺酶 2（TG2）是一种多功能酶，通过促进转化生长因子-β1 和细胞外基质蛋白的交联参与纤维化。这些功能依赖于开放构象，而 TG2 的闭状态可以诱导血管舒张。我们探讨了 TG2 在闭状态下对肾脏纤维化和血压（BP）调节发展的潜在保护作用。
我们研究了单侧输尿管梗阻（UUO）小鼠模型，用 LDN27219 治疗以促进 TG2 的闭构象。小鼠接受 7 天 UUO 或假手术，并分别用载体（n=10）、LDN27219（15mg/kg/12h，n=9）或坎地沙坦（5mg/kg/天，n=10）治疗。通过 Western blot、qPCR 和组织学评估肾脏 TG2 和促纤维化介质的表达，并通过尾套测量 BP。
梗阻肾脏的纤维连接蛋白、胶原 3α1（Col3α1）、α-平滑肌肌动蛋白和胶原染色的 mRNA 和蛋白表达增加。尽管肾脏 TG2 的 mRNA 增加，但所有 UUO 组的蛋白表达均降低，但载体和坎地沙坦组的转酰胺酶活性增加。LDN27219 降低了纤维连接蛋白和 Col3α1 的 mRNA 表达，但它们的蛋白表达保持不变。与 LDN27219 相反，坎地沙坦降低了 BP，而不影响促纤维化生物标志物的表达。
肾脏 TG2 的 mRNA 和蛋白表达水平似乎分离，转酰胺酶活性增加。LDN27219 影响肾脏促纤维化标志物的 mRNA 水平并降低转酰胺酶活性，但不影响胶原含量或 BP。我们的研究结果表明，闭状态下的 TG2 在分子水平上具有抗纤维化作用。
