Elsevier

Urology

Volume 66, Issue 6, December 2005, Pages 1349-1353
Urology

Basic science
CME article
Transforming growth factor-beta1–induced hypertrophy and matrix expression in human bladder smooth muscle cells

https://doi.org/10.1016/j.urology.2005.06.124Get rights and content

Abstract

Objectives

To determine whether transforming growth factor beta (TGF-beta) could activate hyperplasia, hypertrophy, and altered collagen expression in human detrusor smooth muscle cells (SMCs).

Methods

Human bladder SMCs were treated in vitro with TGF-beta1 and analyzed for changes in both proliferative and hypertrophic responses by cell number and volume measurements, as well as for alterations in extracellular matrix gene and protein expression by Northern blot and enzyme-linked immunosorbent assay.

Results

Proliferation of bladder SMCs was refractory to TGF-beta1, whereas the cells became hypertrophic upon TGF-beta1 treatment. The interstitial collagens, types I and III, were increased significantly in TGF-beta1–treated cultures in a dose-dependent manner. These increases were blocked in the presence of TGF-beta1 neutralizing antibody and also when cultures were treated with the protein synthesis inhibitor cycloheximide, indicating that new protein synthesis is necessary for upregulation of the interstitial collagens. Messenger ribonucleic acid transcripts for both the COL1A1 and COL3A1 genes were elevated at 4, 6, and 24 hours in TGF-beta1–treated cultures, preceding the expression of the collagenous protein, showing that TGF-beta1 effects on bladder smooth muscle occur, at least in part, at the transcriptional level.

Conclusions

These results indicate that human bladder SMCs have the potential to mediate both a hypertrophic and fibrotic response upon TGF-beta1 stimulation.

Section snippets

Material and methods

Smooth muscle cells were isolated from human bladder tissue removed during surgery for ureteral reimplantation with appropriate institutional approvals, as previously described.14 Cells were propagated in 45% Dulbecco’s minimal essential medium, 45% Hams-F12, 10% fetal bovine serum (FBS), 15 mmol/L N-2-hydroxyethylpiperazine-N′-2-ethanesulfonic acid, penicillin/streptomycin, and amphotericin B in a humidified atmosphere of 5% CO2 in air and utilized from population doubling levels 2 to 8.

Cells

Hypertrophy and Hyperplasia

Bladder SMCs were treated with increasing concentrations of TGF-beta1, and total cell number was determined daily for 6 days. Smooth muscle cell proliferative response was refractory to all concentrations of TGF-beta1. No SMC hyperplasia response to increasing concentrations of TGF-beta1 was detected (data not shown). In contrast, TGF-beta1–treated SMCs became hypertrophic (30%–40% size increase) compared with nontreated control SMCs (Table I).

Collagen Protein Expression

Confluent detrusor SMC cultures were incubated in

Comment

These in vitro studies were carried out to determine whether bladder SMCs could respond to the profibrotic cytokine TGF-beta1 and whether the response could mimic in vivo conditions of hyperplasia/hypertrophy and altered collagen expression in obstructed bladders. Bladder SMCs did not show a proliferative response to TGF-beta1, similar to other cell types—vascular SMCs, mesangial cells, and also urothelial cells, in which TGF-beta1 can promote development of a differentiated urothelial layer in

Conclusions

Human bladder smooth muscle cells mediate both a hypertrophic and fibrotic response upon TGF-beta1 stimulation, which results in significant changes in the physiologic properties of the bladder.

Acknowledgment

To Z.Z. Tian for his technical assistance.

References (24)

  • M.W. Chen et al.

    Peptide growth factors in normal and hypertrophied bladder

    World J Urol

    (1995)
  • J.E.J. Schultz et al.

    TGF-β1 mediates the hypertrophic cardiomyocyte growth induced by angiotensin II

    J Clin Invest

    (2002)
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