Conditional deletion of Krüppel-like factor 4 delays downregulation of smooth muscle cell differentiation markers but accelerates neointimal formation following vascular injury

Tadashi Yoshida, Klaus H. Kaestner, Gary K. Owens

Research output: Contribution to journalArticle

142 Citations (Scopus)

Abstract

Phenotypic switching of smooth muscle cells (SMCs) plays a key role in vascular proliferative diseases. We previously showed that Krüppel-like factor 4 (Klf4) suppressed SMC differentiation markers in cultured SMCs. Here, we derive mice deficient for Klf4 by conditional gene ablation and analyze their vascular phenotype following carotid injury. Klf4 expression was rapidly induced in SMCs of control mice after vascular injury but not in Klf4-deficient mice. Injury-induced repression of SMC differentiation markers was transiently delayed in Klf4-deficient mice. Klf4 mutant mice exhibited enhanced neointimal formation in response to vascular injury caused by increased cellular proliferation in the media but not an altered apoptotic rate. Consistent with these findings, cultured SMCs overexpressing Klf4 showed reduced cellular proliferation, in part, through the induction of the cell cycle inhibitor, p21 WAF1/Cip1 via increased binding of Klf4 and p53 to the p21 WAF1/Cip1 promoter/enhancer. In vivo chromatin immunoprecipitation assays also showed increased Klf4 binding to the promoter/enhancer regions of the p21 WAF1/Cip1 gene and SMC differentiation marker genes following vascular injury. Taken together, we have demonstrated that Klf4 plays a critical role in regulating expression of SMC differentiation markers and proliferation of SMCs in vivo in response to vascular injury.

Original languageEnglish
Pages (from-to)1548-1557
Number of pages10
JournalCirculation Research
Volume102
Issue number12
DOIs
Publication statusPublished - 2008 Jun 20
Externally publishedYes

Fingerprint

Vascular System Injuries
Differentiation Antigens
Smooth Muscle Myocytes
Cell Differentiation
Down-Regulation
Cell Proliferation
Genes
Chromatin Immunoprecipitation
Wounds and Injuries
Vascular Diseases
Genetic Promoter Regions
Blood Vessels
Cell Cycle
Phenotype

Keywords

  • Conditional knockout mouse
  • Krüppel-like factor
  • P21
  • Vascular injury

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

Cite this

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title = "Conditional deletion of Kr{\"u}ppel-like factor 4 delays downregulation of smooth muscle cell differentiation markers but accelerates neointimal formation following vascular injury",
abstract = "Phenotypic switching of smooth muscle cells (SMCs) plays a key role in vascular proliferative diseases. We previously showed that Kr{\"u}ppel-like factor 4 (Klf4) suppressed SMC differentiation markers in cultured SMCs. Here, we derive mice deficient for Klf4 by conditional gene ablation and analyze their vascular phenotype following carotid injury. Klf4 expression was rapidly induced in SMCs of control mice after vascular injury but not in Klf4-deficient mice. Injury-induced repression of SMC differentiation markers was transiently delayed in Klf4-deficient mice. Klf4 mutant mice exhibited enhanced neointimal formation in response to vascular injury caused by increased cellular proliferation in the media but not an altered apoptotic rate. Consistent with these findings, cultured SMCs overexpressing Klf4 showed reduced cellular proliferation, in part, through the induction of the cell cycle inhibitor, p21 WAF1/Cip1 via increased binding of Klf4 and p53 to the p21 WAF1/Cip1 promoter/enhancer. In vivo chromatin immunoprecipitation assays also showed increased Klf4 binding to the promoter/enhancer regions of the p21 WAF1/Cip1 gene and SMC differentiation marker genes following vascular injury. Taken together, we have demonstrated that Klf4 plays a critical role in regulating expression of SMC differentiation markers and proliferation of SMCs in vivo in response to vascular injury.",
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AU - Kaestner, Klaus H.

AU - Owens, Gary K.

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AB - Phenotypic switching of smooth muscle cells (SMCs) plays a key role in vascular proliferative diseases. We previously showed that Krüppel-like factor 4 (Klf4) suppressed SMC differentiation markers in cultured SMCs. Here, we derive mice deficient for Klf4 by conditional gene ablation and analyze their vascular phenotype following carotid injury. Klf4 expression was rapidly induced in SMCs of control mice after vascular injury but not in Klf4-deficient mice. Injury-induced repression of SMC differentiation markers was transiently delayed in Klf4-deficient mice. Klf4 mutant mice exhibited enhanced neointimal formation in response to vascular injury caused by increased cellular proliferation in the media but not an altered apoptotic rate. Consistent with these findings, cultured SMCs overexpressing Klf4 showed reduced cellular proliferation, in part, through the induction of the cell cycle inhibitor, p21 WAF1/Cip1 via increased binding of Klf4 and p53 to the p21 WAF1/Cip1 promoter/enhancer. In vivo chromatin immunoprecipitation assays also showed increased Klf4 binding to the promoter/enhancer regions of the p21 WAF1/Cip1 gene and SMC differentiation marker genes following vascular injury. Taken together, we have demonstrated that Klf4 plays a critical role in regulating expression of SMC differentiation markers and proliferation of SMCs in vivo in response to vascular injury.

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