Retroviral Overexpression of Decorin Differentially Affects the Response of Arterial Smooth Muscle Cells to Growth Factors

Abstract

Abstract-Decorin is a member of the family of small leucine-rich proteoglycans that are present in blood vessels and synthesized by arterial smooth muscle cells (ASMCs). This proteoglycan accumulates in topographically defined regions of atherosclerotic lesions and may play a role in the development of this disease. However, little is known about whether decorin has specific effects on the cellular events that contribute to atherosclerotic lesion formation. In the present study, rat ASMCs were transduced with a retroviral vector (LDSN) that carries the bovine decorin gene. Compared with vector control cells (LXSN), these cells constitutively overexpress decorin, as verified by Northern and Western analysis and by metabolic labeling. Experiments were performed to examine the responsiveness of decorin-overexpressing rat ASMCs to platelet-derived growth factor (PDGF) and transforming growth factor-␤1 (TGF-␤1), 2 growth factors that affect cell proliferation and extracellular matrix production in atherosclerosis. Decorin-overexpressing cells had decreased [ 3 H]thymidine incorporation into DNA and increased the levels of the cyclin-dependent kinase inhibitors p21 and p27 in the first 24 hours of response to serum and PDGF-BB. However, these effects of decorin were not apparent at 48 or 72 hours after plating and did not result in reduced growth of decorin-overexpressing cells in response to serum and PDGF-BB. In contrast, the growth response of decorinoverexpressing ASMCs to TGF-␤1, as well as the expression of TGF-␤1-responsive genes, such as plasminogen activator inhibitor-1 and versican (an extracellular matrix proteoglycan), was diminished. These results indicate that decorin selectively inhibits the responsiveness of rat ASMCs to TGF-␤1 and suggests that the induction of constitutive decorin overexpression by ASMCs in vivo may have therapeutic value in the inhibition of TGF-␤1-mediated effects on the development of atherosclerotic lesions. ecorin is a family member of the small leucine-rich chondroitin/dermatan sulfate proteoglycans and is present in the extracellular matrix (ECM) of a variety of tissues and cell types. [1][2][3][4] In blood vessels, decorin is confined mainly to the adventitia but is also present in lesser amounts in the smooth muscle-rich media. 5-7 However, in atherosclerosis, decorin accumulates in defined locations throughout the lesions in association with deposited lipoproteins, 8,9 collagen fibrils, 6,8 -10 and the plaque neovasculature. 7 Such findings suggest that decorin might play a role in lipid retention, 11,12 as well as in fibrosis and neovessel growth during the development of the atherosclerotic lesion.Decorin has been shown to influence the proliferative capacity of cells. For example, decorin inhibits the growth of Chinese hamster ovary (CHO) cells 13,14 and various cancer cell lines. 15,16 The growth-inhibitory effect of decorin in malignant cell lines involves an increase in the cyclin kinase inhibitor p21. 15,17 Moreover, the upregulation of decorin expression in nongrow...

Influence of cyclic strain and decorin deficiency on 3D cellularized collagen matrices

“…In addition, the cyclically strained collagen gels seeded with Dcn −/− cells contained the greatest final density of cells, as shown in our previous study [16]. It has been widely recognized that decorin can inhibit cell proliferation, both by sequestering TGF-β and by blocking the epidermal growth factor receptor [26][27][28][29][30].…”

Decorin–TGFβ Axis in Hepatic Fibrosis and Cirrhosis

“…Collectively, the results of the aforementioned studies underline the efficacy of decorin in inhibiting not only matrix deposition, but also migration of fibroblasts, trophoblasts, and differentiation of myocytes (Fischer et al 2001;Droguett et al 2006). Using a cohort of liver pathologies including chronic hepatitis, fibrosis, and cirrhosis, it was previously discovered that high amounts of TGF-β1 colocalize with decorin within the fibrotic areas of the liver (Dudas et al 2001).…”

Retrovirally Mediated Overexpression of Glycosaminoglycan-Deficient Biglycan in Arterial Smooth Muscle Cells Induces Tropoelastin Synthesis and Elastic Fiber Formation in Vitro and in Neointimae after Vascular Injury

“…16,17 Transduced cells were maintained in Dulbecco's minimal essential high glucose medium supplemented with 10% fetal bovine serum, sodium pyruvate, nonessential amino acids, glutamine and penicillin-streptomycin (Invitrogen, Carlsbad, CA). Cells were used between 4 and 8 passages after the initial transduction.…”

“…16,17,24 All surgical procedures were performed according to the Principles of Laboratory Animal Care and the Guide for the Care and Use of Laboratory Animals (National Institutes of Health, publication No. 86-23, revised 1985).…”