Attenuation of proliferation and migration of retinal pericytes in the absence of thrombospondin-1

• Published in: American Journal of Physiology: Cell Physiology Vol. 296; no. 4; pp. C724 - C734
• Main Authors: Scheef, Elizabeth A, Sorenson, Christine M, Sheibani, Nader
• Format: Journal Article
• Language: English
• Published: United States American Physiological Society 01.04.2009
• Subjects: Animals; Apoptosis; Biochemistry; Biomarkers - metabolism; Cell Adhesion; Cell adhesion & migration; Cell Movement; Cell Proliferation; Cell Separation; Cells, Cultured; Enzyme Activation; Mice; Mice, Inbred C57BL; Mice, Knockout; Neovascularization, Physiologic; Pericytes - enzymology; Pericytes - metabolism; Platelet-Derived Growth Factor - metabolism; Proteins; Proto-Oncogene Proteins c-akt - metabolism; Proto-Oncogene Proteins c-sis; Retina; Retina - cytology; Retina - enzymology; Retina - metabolism; Stem cells; Thrombospondin 1 - deficiency; Thrombospondin 1 - genetics; Time Factors; Vascular Biology
• ISSN: 0363-6143; 1522-1563
• DOI: 10.1152/ajpcell.00409.2008

Departments of 1 Ophthalmology and Visual Sciences and 2 Pediatrics, University of Wisconsin School of Medicine, Madison, Wisconsin Submitted 6 August 2008 ; accepted in final form 2 February 2009 Perivascular supporting cells, including vascular smooth muscle cells (VSMCs) and pericytes (PCs), provide instructive signals to adjacent endothelial cells helping to maintain vascular homeostasis. These signals are provided through direct contact and by the release of soluble factors by these cells. Thrombospondin (TSP)1 is a matricellular protein and an autocrine factor for VSMCs. TSP1 activity, along with that of PDGF, regulates VSMC proliferation and migration. However, the manner in which TSP1 and PDGF impact retinal PC function requires further investigation. In the present study, we describe, for the first time, the isolation and culture of retinal PCs from wild-type (TSP1 +/+ ) and TSP1-deficient (TSP1 –/– ) immortomice. We showed that these cells express early and mature markers of PCs, including NG2, PDGF receptor-β, and smooth muscle actin as well as desmin, calbindin, and mesenchymal stem cell markers. These cells were successfully passaged and maintained in culture for several months without significant loss of expression of these markers. TSP1 +/+ PCs proliferated at a faster rate compared with TSP1 –/– PCs. In addition, TSP1 +/+ PCs, like VSMCs, responded to PDGF-BB with enhanced migration and proliferation. In contrast, TSP1 –/– PCs failed to respond to the promigratory and proliferative activity of PDGF-BB. This may be attributed, at least in part, to the limited interaction of PDGF-BB with TSP1 in null cells, which is essential for PDGF proliferative and migratory action. We observed no significant differences in the rates of apoptosis in these cells. TSP1 –/– PCs were also less adherent, expressed increased levels of TSP2 and fibronectin, and had decreased amounts of N-cadherin and v β 3 -integrin on their surface. Thus, TSP1 plays a significant role in retinal PC proliferation and migration impacting retinal vascular development and homeostasis. retinal vasculature; platelet-derived growth factor; platelet-derived growth factor receptor-β; mesenchymal stem cells; perivascular cells; cell adhesion Address for reprint requests and other correspondence: N. Sheibani, Dept. of Ophthalmology and Visual Sciences, Univ. of Wisconsin, 600 Highland Ave., K6/458 CSC, Madison, WI 53792-4673 (e-mail: nsheibanikar{at}wisc.edu )