Han Sang Jun, Jung Jin Ki, Im Seung-Soon, Lee Seong-Ryong, Jang Byeong-Churl, Park Kwon Moo, Kim Jee In
Department of Anatomy and BK21 Plus, Kyungpook National University School of Medicine, Daegu, 700-422, Republic of Korea.
Department of Molecular Medicine and Medical Research Center, Keimyung University School of Medicine, Daegu, Republic of Korea.
Biochem Biophys Res Commun. 2018 Feb 5;496(2):450-454. doi: 10.1016/j.bbrc.2018.01.079. Epub 2018 Jan 11.
Primary cilium is a microtubule-based non-motile organelle that plays critical roles in kidney pathophysiology. Our previous studies revealed that the lengths of primary cilia decreased upon renal ischemia/reperfusion injury and oxidative stress, and restored with recovery. Here, we tested the hypothesis that lack of primary cilium causes epithelial to mesenchymal transition (EMT) of kidney tubule cells. We investigated the alteration of length of primary cilia in TGF-β-induced EMT via visualization of primary cilia by fluorescence staining against acetylated α-tubulin. EMT was determined by measuring mesenchymal protein expression using quantitative PCR and indirect fluorescence staining. As a result, TGF-β treatment decreased ciliary length along with EMT. To test whether defect of primary cilia trigger onset of EMT, cilia formation was disturbed by knock down of ciliary protein using siRNA along with/without TGF-β treatment. Knock down of Arl13b and Ift20 reduced cilia elongation and increased expression of EMT markers such as fibronectin, α-SMA, and collagen III. TGF-β-induced EMT was greater as well in Arl13b and Ift20-knock down cells compared to control cells. Taken together, deficiency of primary cilia trigger EMT and exacerbates it under pro-fibrotic signals.
初级纤毛是一种基于微管的非运动性细胞器，在肾脏病理生理学中发挥着关键作用。我们之前的研究表明，在肾缺血/再灌注损伤和氧化应激时初级纤毛的长度会缩短，并随着恢复而恢复。在此，我们检验了缺乏初级纤毛会导致肾小管上皮细胞向间充质细胞转化（EMT）的假说。我们通过针对乙酰化α-微管蛋白的荧光染色来可视化初级纤毛，研究了转化生长因子-β（TGF-β）诱导的EMT过程中初级纤毛长度的变化。通过定量PCR和间接荧光染色测量间充质蛋白表达来确定EMT。结果显示，TGF-β处理在诱导EMT的同时降低了纤毛长度。为了测试初级纤毛缺陷是否会引发EMT的发生，在有/无TGF-β处理的情况下，使用小干扰RNA（siRNA）敲低纤毛蛋白来干扰纤毛形成。敲低Arl13b和Ift20可减少纤毛伸长，并增加纤连蛋白、α-平滑肌肌动蛋白（α-SMA）和III型胶原蛋白等EMT标志物的表达。与对照细胞相比，TGF-β诱导的EMT在Arl13b和Ift20敲低的细胞中也更明显。综上所述，初级纤毛缺陷会引发EMT，并在促纤维化信号作用下使其加剧。
