Diminished NF-kappaB activation and PDGF-B expression in glomerular endothelial cells subjected to chronic shear stress.
We tested the hypothesis that in endothelial cells, chronic arterial shear stress represses both the transactivator nuclear factor-kappaB (NF-kappaB) and subsequent platelet-derived growth factor (PDGF)-B gene transcription. Bovine aortic endothelial (BAE) and glomerular capillary endothelial (GEN) cells were subjected to chronic (9 days) arterial shear stress (10 dyne/cm(2)). Chronic shear stress reduced PDGF-B transcripts in BAE cells by 59 +/- 23% compared to controls, and by 70 +/- 14% in GEN cells. While PDGF-B mRNA levels were not significantly changed in BAE cells subjected to acute (4 h) shear stress, in GEN cells PDGF-B transcript abundance fell by 59 +/- 3%. PDGF-B mRNA stability was unchanged. We investigated the possibility that these effects were due to decreased nuclear NF-kappaB. NF-kappaB levels were much lower in nuclei of chronic shear stress-treated cells compared to controls. This represents classical inactivation of NF-kappaB since cytoplasmic NF-kappaB/I-kappaB (the inhibitory protein of NF-kappaB) levels were elevated in shear stress-treated cells. Further supporting NF-kappaB regulation of PDGF-B, activation of NF-kappaB by interleukin (IL)-1beta resulted in increased PDGF-B transcript levels. Treatment of cells with MG-132, an inhibitor of NF-kappaB activation, resulted in a dramatic decrease in basal PDGF-B transcript levels, and essentially abrogated the response to IL-1beta. Thus, repression of NF-kappaB activation in endothelial cells by shear stress decreases PDGF-B gene expression, while activators of NF-kappaB increase PDGF-B transcription.
Eng
Eudora
E
Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. e-eng@northwestern.edu
Ballermann
Barbara J
BJ
D000818:Animals; D001011:Aorta / Q000378:metabolism; D015152:Blotting, Northern; D002196:Capillaries / Q000378:metabolism; D002417:Cattle; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism*; D005920:Glomerular Mesangium / Q000166:cytology / Q000378:metabolism*; D015151:Immunoblotting; D007976:Leupeptins / Q000494:pharmacology; D016328:NF-kappa B / Q000378:metabolism*; D020574:Proto-Oncogene Proteins c-sis / Q000096:biosynthesis*; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D013314:Stress, Mechanical; D013997:Time Factors; D014158:Transcription, Genetic
D007976:Leupeptins; D016328:NF-kappa B; D020574:Proto-Oncogene Proteins c-sis; D012333:RNA, Messenger; D012313:RNA; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde