Akt blockade downregulates collagen and upregulates MMP1 in human dermal fibroblasts.

Abstract

Acutely transforming retrovirus AKT8 in rodent T-cell lymphoma (Akt) is a serine/threonine kinase that plays important roles in survival, cell-cycle progression, and cell proliferation, and has recently been implicated in collagen regulation. The aim of this study was to determine the role of Akt in collagen deposition by normal dermal fibroblasts, and to determine the sensitivity of cultured systemic sclerosis (SSc) fibroblasts to Akt inhibition. We show that blockade of Akt using pharmacological inhibitors, small interfering RNA (siRNA), and a dominant-negative Akt mutant led to inhibition of the basal type I collagen production. Furthermore, inhibition of Akt upregulated basal matrix metalloproteinase 1 (MMP1) production and reversed the inhibitory effect of transforming growth factor-beta (TGF-beta) on MMP1 gene expression. In addition, SSc fibroblasts were more sensitive to Akt inhibition, with respect to collagen and MMP1 production. These findings suggest that in human dermal fibroblasts, Akt has dual profibrotic effects, increasing collagen synthesis and decreasing its degradation via downregulation of MMP1. Akt could directly contribute to elevated collagen in SSc fibroblasts and it may represent an attractive target for therapy of SSc fibrosis.

• Authors: Andreea M Bujor, Jaspreet Pannu, Shizhong Bu, Edwin A Smith, Robin C Muise-Helmericks, Maria Trojanowska
• Journal: The Journal of investigative dermatology (J Invest Dermatol) Vol. 128 Issue 8 Pg. 1906-14 (Aug 2008) ISSN: 1523-1747 [Electronic] United States
• PMID: 18323784 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• ACTA2 protein, human
• Actins
• Collagen Type I
• Collagen Type I, alpha 1 Chain
• RNA, Small Interfering
• Transforming Growth Factor beta
• Collagen
• Oncogene Protein v-akt
• Matrix Metalloproteinase 1

Topics

• Actins (metabolism)
• Biopsy
• Case-Control Studies
• Cells, Cultured
• Collagen (metabolism)
• Collagen Type I (metabolism)
• Collagen Type I, alpha 1 Chain
• Dose-Response Relationship, Drug
• Fibroblasts (drug effects, metabolism)
• Gene Expression Regulation
• Humans
• Matrix Metalloproteinase 1 (metabolism)
• Oncogene Protein v-akt (antagonists & inhibitors)
• RNA, Small Interfering (pharmacology)
• Scleroderma, Systemic (metabolism, pathology)
• Skin (cytology, metabolism, pathology)
• Transforming Growth Factor beta (pharmacology)