Cre/loxP approach-mediated downregulation of Pik3c3 inhibits the hypertrophic growth of renal proximal tubule cells.
Cre/loxP approach-mediated downregulation of Pik3c3 inhibits the hypertrophic growth of renal proximal tubule cells.
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DOI：
10.1002/jcp.29811
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发表时间：
2020-12
影响因子：
5.6
通讯作者：
Chen JK
中科院分区：
文献类型：
--
作者：
Liu T;Yuan J;Dai C;Xu J;Li S;Humphreys BD;Kleven DT;Chen JK
肾单位丧失刺激剩余的功能肾单位进行代偿性生长。过度的肾单位生长可能是一种适应不良的反应，它为进行性肾单位损伤奠定了基础，导致肾衰竭。然而，迄今为止，肾单位生长的机制仍然不完全清楚。我们先前的研究揭示了单侧肾切除术（UNX）诱导的肾单位丢失后，剩余肾脏中III类磷脂酰肌醇3-激酶（Pik 3c 3）的激活，但先前的研究未能产生Pik 3c 3基因敲除动物模型。全局Pik 3c 3缺失导致胚胎致死。考虑到肾近端小管细胞构成肾脏的大部分，并在UNX后经历最突出的肥大生长，在本研究中，我们首次使用基于Cre-loxP的方法证明了他莫昔芬诱导的SLC 34 a1启动子驱动的CreERT 2重组酶介导的Pik 3c 3表达下调仅在肾近端小管细胞中足以抑制UNX或氨基酸诱导的肥大肾单位生长。此外，我们的机制研究揭示了SLC 34 a1-CreERT 2重组酶介导的Pik 3c 3下调抑制UNX或氨基酸刺激的溶酶体定位和雷帕霉素复合物1（mTORC 1）在肾近端小管中的机制靶点的信号传导激活。此外，我们使用RNAi的额外细胞培养实验证实，敲低Pik 3c 3表达抑制了氨基酸刺激的mTORC 1信号传导，并在肾近端小管细胞的原代培养物中钝化了细胞生长。总之，我们的体内和体外实验结果表明，Pik 3c 3是一个主要的机械介质，负责传感氨基酸的可用性和启动肥大生长的肾近端小管细胞通过激活mTORC 1-S6 K1-rpS 6信号通路。
Nephron loss stimulates residual functioning nephrons to undergo compensatory growth. Excessive nephron growth may be a maladaptive response that sets the stage for progressive nephron damage, leading to kidney failure. To date, however, the mechanism of nephron growth remains incompletely understood. Our previous study revealed activation of class III phosphatidylinositol 3-kinase (Pik3c3) in the remaining kidney after unilateral nephrectomy (UNX)-induced nephron loss, but previous studies failed to generate a Pik3c3 gene knockout animal model. Global Pik3c3 deletion results in embryonic lethality. Given that renal proximal tubule cells make up the bulk of the kidney and undergo the most prominent hypertrophic growth after UNX, in this study we used Cre-loxP-based approaches for the first time demonstrated that tamoxifen-inducible SLC34a1 promoter-driven CreERT2 recombinase-mediated downregulation of Pik3c3 expression in renal proximal tubule cells alone is sufficient to inhibit UNX- or amino acid-induced hypertrophic nephron growth. Furthermore, our mechanistic studies unveiled that the SLC34a1-CreERT2 recombinase-mediated Pik3c3 downregulation inhibited UNX- or amino acid-stimulated lysosomal localization and signaling activation of mechanistic target of rapamycin complex 1 (mTORC1) in the renal proximal tubules. Moreover, our additional cell culture experiments using RNAi confirmed that knocking down Pik3c3 expression inhibited amino acid-stimulated mTORC1 signaling and blunted cellular growth in primary cultures of renal proximal tubule cells. Together, both our in vivo and in vitro experimental results indicate that Pik3c3 is a major mechanistic mediator responsible for sensing amino acid availability and initiating hypertrophic growth of renal proximal tubule cells by activation of the mTORC1-S6K1-rpS6 signaling pathway.
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DOI：
10.1083/jcb.107.4.1359
发表时间：
1988-10
期刊：
The Journal of cell biology
影响因子：
--
作者：
Haverty TP;Kelly CJ;Hines WH;Amenta PS;Watanabe M;Harper RA;Kefalides NA;Neilson EG
通讯作者：
Neilson EG
影响因子：
2.7
作者：
Hartman, Heather A.;Lai, Hsiao L.;Patterson, Larry T.
通讯作者：
Patterson, Larry T.
影响因子：
13.2
作者：
FOGO, A;ICHIKAWA, I
通讯作者：
ICHIKAWA, I
影响因子：
4.8
作者：
FAGIN, JA;MELMED, S
通讯作者：
MELMED, S
影响因子：
10.5
作者：
Fingar, DC;Salama, S;Blenis, J
通讯作者：
Blenis, J