Translational regulation of renal proximal tubular epithelial cell transforming growth factor-β1 generation by insulin

被引:74
作者
Morrisey, K
Evans, RA
Wakefield, L
Phillips, AO
机构
[1] Cardiff Univ, Inst Nephrol, Cardiff CF14 4XN, S Glam, Wales
[2] NCI, Lab Cell Regulat & Carcinogenesis, Bethesda, MD 20892 USA
基金
英国惠康基金;
关键词
D O I
10.1016/S0002-9440(10)63037-4
中图分类号
R36 [病理学];
学科分类号
100104 ;
摘要
We have previously demonstrated that the proximal tubular cell may contribute to the pathogenesis of renal interstitial fibrosis in diabetes. Transforming growth factor (TGF)-beta1 is one of a group of pro-fibrotic cytokines and growth factors, which have been associated with the development of interstitial fibrosis. The aim of the current study was to examine the effect of insulin on the generation of TGF-beta1. by proximal tubular cells. HK-2 cells were grown to confluence in the absence of insulin, and serum deprived for 48 hours before all experimental manipulations. Addition of insulin (5 mug/ml) to the culture medium led to a time-dependent increase in TGF-beta1 concentration in the cell culture supernatant, and increased incorporation of radiolabeled amino acids into TGF-beta1 suggestive of de novo TGF-beta1 protein synthesis. Addition of insulin did not alter TGF-beta1 mRNA expression as assessed by reverse transcriptase-polymerase chain reaction or Northern analysis. insulin-induced increase in TGF-beta1 concentration was not abrogated by actinomycin D, however, stimulation by insulin, in the presence of cycloheximide led to a dose-dependent decrease in TGF-beta1 production. Addition of insulin had no effect on TGF-beta1 mRNA stability as assessed by actinomycin D chase, but led to increased binding of a cytoplasmic protein to a putative stem loop structure in the 5'-UTR of TGF-beta1 mRNA, previously implicated in the posttranscriptional control of TGF-beta1 synthesis. To address the functional significance of insulin-induced alteration in TGF-beta1 synthesis, we examined its effect on matrix turnover. Insulin stimulated type IV collagen gene expression and an increase in the concentrations of the type IV collagen laid down in the extracellular matrix. This increase in type IV collagen was abrogated when cells were stimulated by insulin in the presence of an anti-TGF-beta1-blocking antibody. in conclusion the data demonstrate that insulin may directly alter the production of TGF-beta1 by renal proximal tubular cells by a posttranscriptional mechanism, and that this may have implications for the increase in extracellular matrix that accompanies diabetic nephropathy.
引用
收藏
页码:1905 / 1915
页数:11
相关论文
共 36 条
  • [1] ADAMO M, 1992, BIOFACTORS, V3, P151
  • [2] Translational control elements in the major human transforming growth factor-β1 mRNA
    Allison, RSH
    Mumy, ML
    Wakefield, LM
    [J]. GROWTH FACTORS, 1998, 16 (02) : 89 - 100
  • [3] INSULIN-LIKE GROWTH-FACTORS AND DIABETES
    BACH, LA
    RECHLER, MM
    [J]. DIABETES-METABOLISM REVIEWS, 1992, 8 (03): : 229 - 257
  • [4] BOHLE A, 1991, PATHOL RES PRACT, V187, P251
  • [5] RESTRICTED HOMOLOGY BETWEEN HUMAN ALPHA-1 TYPE-IV AND OTHER PROCOLLAGEN CHAINS
    BRINKER, JM
    GUDAS, LJ
    LOIDL, HR
    WANG, SY
    ROSENBLOOM, J
    KEFALIDES, NA
    MYERS, JC
    [J]. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1985, 82 (11) : 3649 - 3653
  • [6] HUMAN TRANSFORMING GROWTH FACTOR-BETA COMPLEMENTARY-DNA SEQUENCE AND EXPRESSION IN NORMAL AND TRANSFORMED-CELLS
    DERYNCK, R
    JARRETT, JA
    CHEN, EY
    EATON, DH
    BELL, JR
    ASSOIAN, RK
    ROBERTS, AB
    SPORN, MB
    GOEDDEL, DV
    [J]. NATURE, 1985, 316 (6030) : 701 - 705
  • [7] Both rapamycin-sensitive and -insensitive pathways are involved in the phosphorylation of the initiation factor-4E-binding protein (4E-BP1) in response to insulin in rat epididymal fat-cells
    Diggle, TA
    Moule, SK
    Avison, MB
    Flynn, A
    Foulstone, EJ
    Proud, CG
    Denton, RM
    [J]. BIOCHEMICAL JOURNAL, 1996, 316 : 447 - 453
  • [8] Dixon R, 1999, J AM SOC NEPHROL, V10, P1487
  • [9] Signalling pathways which regulate eIF4E
    Flynn, A
    Vries, RGJ
    Proud, CG
    [J]. BIOCHEMICAL SOCIETY TRANSACTIONS, 1997, 25 (02) : S192 - S192
  • [10] Flyvbjerg A., 1997, KIDNEY INT S, V60, pS12