High glucose stimulates expression of p27Kip1 in cultured mouse mesangial cells: relationship to hypertrophy.
Hypertrophy of mesangial cells is an early hallmark of diabetic nephropathy. We have previously shown that murine mesangial cells (MMC), cultured in high-glucose medium, are arrested in the G1 phase of the cell cycle and undergo hypertrophy. This study was undertaken to test whether high glucose-containing medium influences the expression of p27Kip1, an inhibitor of G1 phase active cyclin-dependent kinases (CDK). Incubation of MMC, in the absence of other factors for 48-96 h, in medium containing high D-glucose (450 mg/dl), stimulated p27Kip1 protein expression but failed to influence mRNA abundance. These effects were independent of the osmolarity of the medium. High glucose-stimulated expression of p27Kip1 involved activation of protein kinase C and was partly dependent on induction of transforming growth factor-beta (TGF-beta). Immunoprecipitation experiments revealed that only small amounts of p27Kip1 protein from MMC grown in high-glucose medium preferentially associates with CDK2 but not with CDK4. The p27Kip1 antisense, but not missense, oligonucleotides inhibited high glucose-stimulated total protein synthesis and facilitated G1 phase exit. Our data showed for the first time that expression of p27Kip1 protein is pivotal in mesangial cell hypertrophy induced by high ambient glucose. These findings may be important in the deciphering of molecular processes causing diabetic glomerular hypertrophy.
Wolf
G
G
Department of Medicine, University of Hamburg, Germany.
Schroeder
R
R
Ziyadeh
F N
FN
Thaiss
F
F
Zahner
G
G
Stahl
R A
RA
D000818:Animals; D042846:CDC2-CDC28 Kinases; D002453:Cell Cycle / Q000187:drug effects; D018797:Cell Cycle Proteins; D002478:Cells, Cultured; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D004791:Enzyme Inhibitors; D016193:G1 Phase; D005920:Glomerular Mesangium / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005947:Glucose / Q000494:pharmacology*; D006984:Hypertrophy; D007930:Leucine / Q000378:metabolism; D051379:Mice; D008815:Mice, Inbred Strains; D008869:Microtubule-Associated Proteins / Q000096:biosynthesis*; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger / Q000378:metabolism; D013873:Thionucleotides; D025521:Tumor Suppressor Proteins
C493961:Cdkn1b protein, mouse; D018797:Cell Cycle Proteins; D004791:Enzyme Inhibitors; D008869:Microtubule-Associated Proteins; D016376:Oligonucleotides, Antisense; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D013873:Thionucleotides; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495893:Cdk2 protein, mouse; C495902:Cdk4 protein, mouse; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases; D007930:Leucine; D005947:Glucose