Chuang Chao-Tang, Guh Jinn-Yuh, Lu Chi-Yu, Wang Yeng-Tseng, Chen Hung-Chun, Chuang Lea-Yea
Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
Department of Internal Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
J Cell Mol Med. 2015 Jun;19(6):1234-44. doi: 10.1111/jcmm.12472. Epub 2015 Mar 27.
Six-transmembrane epithelial antigen of prostate 4 (Steap4)-knockout mice develop hyperglycaemia and inflammation whereas Steap4 overexpression attenuates atherosclerosis in diabetic mice. Thus, we studied the roles of Steap4 in high glucose (HG, 27.5 mM) or S100B (1 μM, a ligand for the receptor for advanced glycation end-product or RAGE)-induced effects in mouse mesangial (MES13) cells. We found that HG-induced Steap4 protein expression was dependent on S100B. HG increased cell membrane, but not cytosolic, Steap4 protein expression. HG increased protein-protein interaction between Steap4 and S100B, which was confirmed by mass spectrometry of immunoprecipitated S100B. SP600125, LY294002 and AG490 attenuated S100B-induced Steap4 protein expression or gene transcriptional activity. A mutation in signal transducer and activator of transcription 3 (Stat3) site 2 of the Steap4 promoter constructs resulted in a marked decrease in HG or S100B-induced activation of Steap4 gene transcription. Overexpression of Steap4 attenuates HG or S100B-induced collagen IV, fibronectin and cyclooxygenase 2 protein expression. Overexpression of Steap4 attenuates HG or S100B-induced transforming growth factor-β (TGF-β). Moreover, overexpression of Steap4 attenuates S100B-induced signalling. Finally, overexpressing Steap4 attenuated renal expression of fibronectin, S100B, TGF-β, type IV collagen, p-Akt, p-extracellular signal regulated kinase 1/2 and p-Stat3 in streptozotocin-diabetic mice. Thus, overexpression of Steap4 attenuated HG or S100B-induced effects in MES13 cells and attenuated some of S100B-induced effects in diabetic mouse kidneys.
前列腺六跨膜上皮抗原4（Steap4）基因敲除小鼠会出现高血糖和炎症反应，而Steap4过表达则可减轻糖尿病小鼠的动脉粥样硬化。因此，我们研究了Steap4在高糖（HG，27.5 mM）或S100B（1 μM，晚期糖基化终产物受体或RAGE的配体）诱导的小鼠系膜（MES13）细胞效应中的作用。我们发现HG诱导的Steap4蛋白表达依赖于S100B。HG增加了细胞膜而非胞质中的Steap4蛋白表达。HG增加了Steap4与S100B之间的蛋白质-蛋白质相互作用，这通过免疫沉淀的S100B的质谱分析得到证实。SP600125、LY294002和AG490减弱了S100B诱导的Steap4蛋白表达或基因转录活性。Steap4启动子构建体的信号转导和转录激活因子3（Stat3）位点2的突变导致HG或S100B诱导的Steap4基因转录激活显著降低。Steap4过表达减弱了HG或S100B诱导的IV型胶原、纤连蛋白和环氧化酶2蛋白表达。Steap4过表达减弱了HG或S100B诱导的转化生长因子-β（TGF-β）。此外，Steap4过表达减弱了S100B诱导的信号传导。最后，在链脲佐菌素诱导的糖尿病小鼠中，Steap4过表达减弱了肾组织中纤连蛋白、S100B、TGF-β、IV型胶原、p-Akt、p-细胞外信号调节激酶1/2和p-Stat3的表达。因此，Steap4过表达减弱了HG或S100B在MES13细胞中诱导的效应，并减弱了糖尿病小鼠肾脏中一些S100B诱导的效应。
