CRTC2 通过 CREB-Smad2/3 通路激活糖尿病肾病的上皮间质转化。
CRTC2 activates the epithelial-mesenchymal transition of diabetic kidney disease through the CREB-Smad2/3 pathway.
机构信息
Changchun University of Traditional Chinese Medicine, Changchun, 130012, China.
The Second Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, 250000, China.
出版信息
Mol Med. 2023 Oct 26;29(1):146. doi: 10.1186/s10020-023-00744-0.
BACKGROUND
Epithelial-mesenchymal transition (EMT) plays a key role in tubulointerstitial fibrosis, which is a hallmark of diabetic kidney disease (DKD). Our previous studies showed that CRTC2 can simultaneously regulate glucose metabolism and lipid metabolism. However, it is still unclear whether CRTC2 participates in the EMT process in DKD.
METHODS
We used protein‒protein network (PPI) analysis to identify genes that were differentially expressed during DKD and EMT. Then, we constructed a diabetic mouse model by administering STZ plus a high-fat diet, and we used HK-2 cells that were verified to confirm the bioinformatics research results. The effects that were exerted by CRTC2 on epithelial-mesenchymal transition in diabetic kidney disease through the CREB-Smad2/3 signaling pathway were investigated in vivo and in vitro by real-time PCR, WB, IHC and double luciferase reporter gene experiments.
RESULTS
First, bioinformatics research showed that CRTC2 may promote EMT in diabetic renal tubules through the CREB-Smad2/3 signaling pathway. Furthermore, the Western blotting and real-time PCR results showed that CRTC2 overexpression reduced the expression of E-cadherin in HK-2 cells. The CRTC2 and α-SMA levels were increased in STZ-treated mouse kidneys, and the E-cadherin level was reduced. The luciferase activity of α-SMA, which is the key protein in EMT, was sharply increased in response to the overexpression of CRTC2 and decreased after the silencing of CREB and Smad2/3. However, the expression of E-cadherin showed the opposite trends. In the real-time PCR experiment, the mRNA expression of α-SMA increased significantly when CRTC2 was overexpressed but partially decreased when CREB and Smad2/3 were silenced. However, E-cadherin expression showed the opposite result.
CONCLUSION
This study demonstrated that CRTC2 activates the EMT process via the CREB-Smad2/3 signaling pathway in diabetic renal tubules.
背景
上皮-间充质转化（EMT）在肾小管间质纤维化中起关键作用，这是糖尿病肾病（DKD）的标志。我们之前的研究表明，CRTC2 可以同时调节葡萄糖代谢和脂质代谢。然而，CRTC2 是否参与 DKD 中的 EMT 过程仍不清楚。
方法
我们使用蛋白质-蛋白质网络（PPI）分析来鉴定 DKD 和 EMT 过程中差异表达的基因。然后，我们通过给予 STZ 加高脂肪饮食构建了糖尿病小鼠模型，并使用 HK-2 细胞验证了生物信息学研究结果。通过实时 PCR、WB、IHC 和双荧光素酶报告基因实验，研究了 CRTC2 通过 CREB-Smad2/3 信号通路对糖尿病肾病上皮-间充质转化的影响。
结果
首先，生物信息学研究表明，CRTC2 可能通过 CREB-Smad2/3 信号通路促进糖尿病肾小管中的 EMT。此外，Western blot 和实时 PCR 结果表明，CRTC2 过表达降低了 HK-2 细胞中 E-钙黏蛋白的表达。STZ 处理的小鼠肾脏中 CRTC2 和 α-SMA 的水平增加，而 E-钙黏蛋白的水平降低。α-SMA 的荧光素酶活性（EMT 的关键蛋白）对 CRTC2 的过表达反应急剧增加，而在 CREB 和 Smad2/3 沉默后降低。然而，E-钙黏蛋白的表达则呈现相反的趋势。在实时 PCR 实验中，当 CRTC2 过表达时，α-SMA 的 mRNA 表达显著增加，而当 CREB 和 Smad2/3 沉默时部分减少。然而，E-钙黏蛋白的表达则呈现相反的结果。
结论
本研究表明，CRTC2 通过 CREB-Smad2/3 信号通路在糖尿病肾小管中激活 EMT 过程。
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