Estrogen inhibits mechanical strain-induced mitogenesis in human vascular smooth muscle cells via down-regulation of Sp-1

Shanhong Ling, Gang Deng, Harlan E. Ives, Kanu Chatterjee, Gabor M. Rubanyi, Paul A. Komesaroff, Krishnankutty Sudhir

Research output: Contribution to journalArticleResearchpeer-review


Objective: The cellular basis of the cardioprotective effects of estrogen are largely unknown. An inhibitory effect on vascular smooth muscle (VSM) growth has been proposed. We examined the effect of 17β-estradiol (E2) on mechanical strain-induced mitogenesis in human fetal VSM cells. Methods and results: Cells were grown on fibronectin-coated plates with silicone-elastomer bottoms, and exposed to cyclic mechanical strain (60 cycles/min), with and without E2 (1 nmol/l), for 48 h. [3H]-Thymidine incorporation was measured during the last 6 h. Strain induced 1.5-2 fold increases in DNA synthesis that were attenuated by antibodies to platelet-derived growth factor (PDGF) AA and BB. Strain also induced increases both in mRNA and protein levels of Sp-1, a transcription factor that binds to the PDGF-A gene promoter site. E2 attenuated strain-induced mitogenesis, and also increases in mRNA and protein levels of Sp-1. The estrogen receptor (ER) antagonist ICI 182,780 (100 nmol/l) reversed the inhibitory effect of E2 on strain-induced increases in DNA synthesis and Sp-1 protein. RT-PCR analysis showed presence of both ER-α and -β in these cells. Conclusions: Estrogen inhibits strain-induced mitogenesis in human VSM cells via an ER mediated process involving down-regulation of the transcription factor Sp-1.

Original languageEnglish
Pages (from-to)108-114
Number of pages7
JournalCardiovascular Research
Issue number1
Publication statusPublished - 10 Apr 2001
Externally publishedYes


  • Gender
  • Growth factors
  • Platelets
  • Smooth muscle

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