Involvement of NF-kappaB in high glucose-induced alteration of alpha-methyl-D-glucopyranoside (alpha-MG) uptake in renal proximal tubule cells.
Although recent data have shown that nuclear factor-kappa B (NF-kappaB) is activated in tubules and glomeruli in various experimental models of renal injury, biological significance of NF-kappaB activation in diabetic renal injury is not clear. Thus, this study performed to investigate involvement of NF-kappaB in high glucose-induced Na+/glucose cotransporters' dysfunction in primary cultured renal proximal tubules cells (PTCs). Treatment with 25 mM glucose for 48 hr increased NF-kappaB DNA binding activity by five times compared to 5 mM glucose (control). The specificity of the binding reaction was confirmed by competition studies. The level of NF-kappaB p65 protein by treatment with 25 mM glucose for 48 hr was increased by about 2-fold compared to 5 mM glucose in the nuclear extracts. Also, Western blot analysis of IkappaB-alpha protein showed that levels of IkappaB-alpha protein were clearly decreased after incubation with 25 mM glucose compare to 5 mM glucose. To examine the relationship of NF-kappaB and oxidative stress or PKC in the high glucose-induced inhibition of [14C]- alpha-methyl-D-glucopyranoside (alpha-MG) uptake, PKC inhibitors and antioxidants effectively blocked high glucose-induced activation of NF-kappaB although these themselves had no significant effects. In addition, high glucose-induced inhibition of alpha-MG uptake was prevented by NF-kappaB inhibitors. In conclusion, high glucose inhibits, in part, alpha-MG uptake through NF-kappaB activation mediated by oxidative stress and PKC activation in the primary cultured rabbit renal proximal tubule cells.
Han
Ho Jae
HJ
Department of Veterinary Physiology, College of Veterinary Medicine, Hormone Research Center, Chonnam National University. Hjhan@chonnam.ac.k
Jeon
Young Jin
YJ
Lee
Yun Jung
YJ
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001665:Binding Sites; D001692:Biological Transport / Q000187:drug effects; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D005786:Gene Expression Regulation; D005947:Glucose / Q000494:pharmacology*; D020672:I-kappa B Proteins / Q000378:metabolism; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D008054:Lipid Peroxides / Q000378:metabolism; D008297:Male; D008757:Methylglucosides / Q000378:metabolism*; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D011817:Rabbits; D012964:Sodium / Q000378:metabolism; D013379:Substrate Specificity; D051996:Transcription Factor RelA
D000975:Antioxidants; D020672:I-kappa B Proteins; D008054:Lipid Peroxides; D008757:Methylglucosides; D016328:NF-kappa B; D051996:Transcription Factor RelA; D000072000:NF-KappaB Inhibitor alpha; D004247:DNA; D012964:Sodium; D011493:Protein Kinase C; D005947:Glucose