TY - JOUR
T1 - High glucose and diabetes enhanced store-operated Ca2+ entry and increased expression of its signaling proteins in mesangial cells
AU - Chaudhari, Sarika
AU - Wu, Peiwen
AU - Wang, Yanxia
AU - Ding, Yanfeng
AU - Yuan, Joseph
AU - Begg, Malcolm
AU - Ma, Rong
PY - 2014/5/1
Y1 - 2014/5/1
N2 - The present study was conducted to determine whether and how store-operated Ca2+ 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 Ca2+ channels. Similarly, the inositol 1,4,5-trisphosphate-induced store-operated Ca2+ currents were significantly enhanced in the MCs treated with HG for 7 days, and the enhanced response was abolished by both GSK-7975A and La3+. In contrast, receptor-operated Ca2+ 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.
AB - The present study was conducted to determine whether and how store-operated Ca2+ 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 Ca2+ channels. Similarly, the inositol 1,4,5-trisphosphate-induced store-operated Ca2+ currents were significantly enhanced in the MCs treated with HG for 7 days, and the enhanced response was abolished by both GSK-7975A and La3+. In contrast, receptor-operated Ca2+ 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.
KW - Diabetic nephropathy
KW - High glucose
KW - Mesangial cells
KW - Orai1
KW - STIM1
UR - http://www.scopus.com/inward/record.url?scp=84900533240&partnerID=8YFLogxK
U2 - 10.1152/ajprenal.00463.2013
DO - 10.1152/ajprenal.00463.2013
M3 - Article
C2 - 24623143
AN - SCOPUS:84900533240
SN - 0363-6127
VL - 306
SP - F1069-F1080
JO - American Journal of Physiology - Renal Physiology
JF - American Journal of Physiology - Renal Physiology
IS - 9
ER -