Activation of PKC-beta(I) in glomerular mesangial cells is associated with specific NF-kappaB subunit translocation.
Changes in expression and activity of protein kinase C (PKC) isoforms and early transcription factors may account for alterations in cell behavior seen in diabetes. We studied the expression of PKC-beta(I) in rat glomerular mesangial cells (MCs) cultured in normal or high glucose and compared it with the temporal and spatial expression of dimeric transcription factor (NF-kappaB) p50 and p65. The results show that in unstimulated cells PKC-beta(I) and NF-kappaB p50 are distributed in the cytosol and, on stimulation, their distribution is perinuclear and they are localized to the membrane. Serum-starved MCs cultured in high-glucose medium exhibit a predominantly cytosolic localization of PKC-beta(I) and both p50 and p65 NF-kappaB. However, phorbol 12-myristate 13-acetate (PMA) stimulation of cells grown in the presence of high glucose resulted in membrane translocation of PKC-beta(I) that was associated with nuclear translocation of NF-kappaB p65, but not NF-kappaB p50. Moreover, the translocation to the nucleus for NF-kappaB p65 was significantly higher in MCs exposed to high glucose compared with those exposed to normal glucose. These observations indicate that the NF-kappaB p65, but not NF-kappaB p50, expression and translocation pattern mirrors that of PKC-beta(I), which may be one important pathway by which signaling is enhanced in the high-glucose state.
Kumar
A
A
Division of Nephrology, Veterans Affairs Medical Center, 10701 East Blvd., Cleveland, OH 44106, USA. axk38@po.cwru.edu
Hawkins
K S
KS
Hannan
M A
MA
Ganz
M B
MB
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002273:Carcinogens / Q000494:pharmacology; D002478:Cells, Cultured; D003928:Diabetic Nephropathies / Q000378:metabolism; D005920:Glomerular Mesangium / Q000737:chemistry / Q000166:cytology / Q000201:enzymology*; D005947:Glucose / Q000494:pharmacology; D006943:Hyperglycemia / Q000378:metabolism; D007527:Isoenzymes / Q000032:analysis / Q000378:metabolism*; D008297:Male; D016328:NF-kappa B / Q000032:analysis / Q000378:metabolism*; D011493:Protein Kinase C / Q000032:analysis / Q000378:metabolism*; D064546:Protein Kinase C beta; D051381:Rats; D017207:Rats, Sprague-Dawley; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D002273:Carcinogens; D007527:Isoenzymes; D016328:NF-kappa B; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D005947:Glucose; D013755:Tetradecanoylphorbol Acetate