van Beusekom Cyrina D, Zimmering Tanja M
1 Veterinary Pharmacology, Pharmacotherapy and Toxicology, Institute for Risk Assessment Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
2 Boehringer Ingelheim Animal Health GmbH, Ingelheim, Germany.
J Feline Med Surg. 2019 Aug;21(8):780-787. doi: 10.1177/1098612X18805862. Epub 2018 Oct 22.
The aim of this study was to evaluate the role of angiotensin II (AT-II) and its main mediator, transforming growth factor beta 1 (TGF-β1), in the development of feline renal fibrosis.
Expression of marker genes indicating epithelial-to-mesenchymal transition (EMT), profibrotic mediators and matricellular proteins was measured in feline kidney epithelial cells (Crandell Rees feline kidney [CRFK] cells) after incubation with AT-II and/or TGF-β1.
Cells incubated with TGF-β1 or the combination of TGF-β1 with AT-II showed clear EMT with more stretched fibroblastic cells, whereas the cells incubated without TGF-β1 and AT-II (control) showed more epithelial cells. Gene expression of collagen type I (), tenascin-C (), trombospondin-1 (), connective tissue growth factor () and alpha-smooth muscle actin () increased significantly after incubation of the CRFK cells with TGF-β1 or TGF-β1 in combination with AT-II for 12 h. As incubation of the CRFK cells with only AT-II did not show any significant rise in gene expression of the above-mentioned genes, this was further investigated. In contrast to healthy feline kidney tissue, CRFK cells showed almost no expression of the AT-II type 1 (AT) receptor.
TGF-β1 significantly induced expression of the EMT marker gene α-SMA, profibrotic mediator , and fibrogenic proteins , and in CRFK cells. The effect of TGF-β1 on myofibroblast formation was also observed by the stretched appearance of the CRFK cells. As CRFK cells expressed almost no AT receptors, this cell line proved not suitable for testing the efficacy of drugs that interact with the AT receptor. As AT-II stimulates the effects of TGF-β1 in mammals, the results of this study suggest an indirect profibrotic effect of AT-II besides the demonstrated profibrotic effect of TGF-β1 and thus the development of feline renal fibrosis. Modulation of EMT or proliferation of myofibroblasts could serve as a diagnostic tool and a novel therapeutic target to inhibit renal fibrogenesis, and could possibly serve in the therapy of feline renal fibrosis.
本研究旨在评估血管紧张素II（AT-II）及其主要介质转化生长因子β1（TGF-β1）在猫肾纤维化发展过程中的作用。
在猫肾上皮细胞（克兰德尔里斯猫肾[CRFK]细胞）与AT-II和/或TGF-β1孵育后，检测指示上皮-间充质转化（EMT）的标记基因、促纤维化介质和基质细胞蛋白的表达。
与TGF-β1或TGF-β1与AT-II组合孵育的细胞呈现明显的EMT，出现更多伸长的成纤维细胞样细胞，而未与TGF-β1和AT-II孵育的细胞（对照）显示更多上皮细胞。CRFK细胞与TGF-β1或TGF-β1与AT-II组合孵育12小时后，I型胶原（）、腱生蛋白-C（）、血小板反应蛋白-1（）、结缔组织生长因子（）和α-平滑肌肌动蛋白（）的基因表达显著增加。由于仅用AT-II孵育CRFK细胞未显示上述基因的表达有任何显著升高，因此对此进行了进一步研究。与健康猫肾组织相比，CRFK细胞几乎不表达AT-II 1型（AT）受体。
TGF-β1显著诱导CRFK细胞中EMT标记基因α-SMA、促纤维化介质和纤维化蛋白、以及的表达。CRFK细胞伸长的形态也观察到TGF-β1对肌成纤维细胞形成的影响。由于CRFK细胞几乎不表达AT受体，该细胞系被证明不适用于测试与AT受体相互作用的药物的疗效。由于AT-II在哺乳动物中刺激TGF-β1的作用，本研究结果表明除了已证明的TGF-β1的促纤维化作用外，AT-II还具有间接促纤维化作用，从而参与猫肾纤维化的发展。EMT的调节或肌成纤维细胞的增殖可作为抑制肾纤维化的诊断工具和新的治疗靶点，并可能用于猫肾纤维化的治疗。
