title: High glucose and diabetes enhanced store-operated Ca(2+) entry and increased expression of its signaling proteins in mesangial cells.
abstract: The present study was conducted to determine whether and how store-operated Ca(2+) entry (SOCE) in glomerular mesangial cells (MCs) was altered by high glucose (HG) and diabetes. Human MCs were treated with either normal glucose or HG for different time periods. Cyclopiazonic acid-induced SOCE was significantly greater in the MCs with 7-day HG treatment and the response was completely abolished by GSK-7975A, a selective inhibitor of store-operated Ca(2+) channels. Similarly, the inositol 1,4,5-trisphosphate-induced store-operated Ca(2+) currents were significantly enhanced in the MCs treated with HG for 7 days, and the enhanced response was abolished by both GSK-7975A and La(3+). In contrast, receptor-operated Ca(2+) entry in MCs was significantly reduced by HG treatment. Western blotting showed that HG increased the expression levels of STIM1 and Orai1 in cultured MCs. A significant HG effect occurred at a concentration as low as 10 mM, but required a minimum of 7 days. The HG effect in cultured MCs was recapitulated in renal glomeruli/cortex of both type I and II diabetic rats. Furthermore, quantitative real-time RT-PCR revealed that a 6-day HG treatment significantly increased the mRNA expression level of STIM1. However, the expressions of STIM2 and Orai1 transcripts were not affected by HG. Taken together, these results suggest that HG/diabetes enhanced SOCE in MCs by increasing STIM1/Orai1 protein expressions. HG upregulates STIM1 by promoting its transcription but increases Orai1 protein through a posttranscriptional mechanism.
authors.affiliation: 3500 Camp Bowie Blvd., Dept. of Integrative Physiology, Univ. of North Texas Health Science Center, Fort Worth, TX 76107. rong.ma@unthsc.edu.
authors.forename: Sarika
authors.initials: S
authors.lastname: Chaudhari
authors.forename: Peiwen
authors.initials: P
authors.lastname: Wu
authors.forename: Yanxia
authors.initials: Y
authors.lastname: Wang
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Ding
authors.forename: Joseph
authors.initials: J
authors.lastname: Yuan
authors.forename: Malcolm
authors.initials: M
authors.lastname: Begg
authors.forename: Rong
authors.initials: R
authors.lastname: Ma
mesh_terms: D000818:Animals; D002120:Calcium Channel Agonists / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects; D002478:Cells, Cultured; D003921:Diabetes Mellitus, Experimental / Q000150:complications / Q000235:genetics / Q000378:metabolism; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000235:genetics / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000235:genetics / Q000378:metabolism; D003928:Diabetic Nephropathies / Q000209:etiology / Q000235:genetics / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D015640:Ion Channel Gating / Q000187:drug effects; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D050527:Mesangial Cells / Q000187:drug effects / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D000071740:ORAI1 Protein; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D000071737:Stromal Interaction Molecule 1; D013997:Time Factors; D015533:Transcriptional Activation; D015854:Up-Regulation
chemical_list: D002120:Calcium Channel Agonists; D002121:Calcium Channel Blockers; D015220:Calcium Channels; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D000071740:ORAI1 Protein; C510746:ORAI1 protein, human; C532493:Orai1 protein, rat; D012333:RNA, Messenger; C103530:STIM1 protein, human; C518857:Stim1 protein, rat; D000071737:Stromal Interaction Molecule 1; D015544:Inositol 1,4,5-Trisphosphate; D005947:Glucose
keywords: Orai1; STIM1; diabetic nephropathy; high glucose; mesangial cells; store-operated Ca2+ entry