Distribution of beta-1 integrin in the developing rat heart.

Abstract

Cell-cell and cell-matrix interactions play critical roles in various developmental processes including differentiation, proliferation, and migration. Members of the integrin family of cell surface components are important mediators of these cell-extracellular matrix (ECM) contacts or interactions.The ECM provides signals to individual cells essential for development and differentiation and plays essential roles in establishing and maintaining the complex structure of the vertebrate heart. Integrins provide a fundamental link for transduction of developmental signals to cells. Integrin expression by cardiac myqtes is altered during neonatal heart development and disease; however, little is known regarding the spatial and temporal patterns of integrin expression during embryonic and fetal heart development. Essential to understanding the role of integrins in the organization of the heart, the present studies have localized 0-1 integrin protein and mRNA in fetal and neonatal rat hearts. b1 integrin is predominantly found in regions of remodeling (trabeculae) in the early heart (10-13 days of gestation). Later in development (15 days of gestation onward), b1 integrin is abundant in regions containing an elaborate ECM, such as the valves. These studies further support the hypothesis that the expressions of integrins and ECM are coordinately regulated in the developing heart. ( J Hisrochem Cytochem

Synthesis of Extracellular Matrix and Adhesion Through β 1 Integrins Are Critical for Fetal Ventricular Myocyte Proliferation

“…fibronectin 17 and types I and III collagen, 22 and ventricular myocytes produce only type IV collagen as determined by in situ hybridization. 22 In this study, we documented that HFVMs synthesize collagen in culture, with a significant increase in production in response to FBS (Figure 3).…”

“…14,15 In the heart, the ECM is important for both myocardial structure and function 16,17 and is involved in several important developmental processes during cardiac embryogenesis. 18 -21 The extensive change in ECM components within the perinatal period 22 and the developmental changes in cardiac myocyte attachment to various components of the ECM that correspond to changes in integrin receptor expression suggest a potential role in regulating myocyte proliferation. For example, ␤ 1 integrin expression is highest in fetal and lowest in adult cardiac myocytes.…”

Cadherin-mediated adhesion is essential for myofibril continuity across the plasma membrane but not for assembly of the contractile apparatus

“…The integrin family of cell adhesion receptors mediates these interactions by binding to the substrata components, including collagens, fibronectins and laminins. Similar to Ncadherin, β1 integrin is expressed in the developing and mature myocardium (Carver et al, 1994;Terracio et al, 1991). In the presence of anti-β1 integrin antibodies, normal cell spreading and myofibril organization was perturbed in cultured neonatal rat cardiomyocytes (Hilenski et al, 1992).…”

Archvillin, a muscle-specific isoform of supervillin, is an early expressed component of the costameric membrane skeleton

“…Costameres were originally defined immunocytologically as a rib-like lattice containing vinculin, spectrin and γ-actin Pardo et al, 1983). These structures also contain dystrophin (Gossrau, 1998;Porter et al, 1992;Rybakova et al, 2000;Zhou et al, 1998), dystrophin-associated glycoproteins (Rahkila et al, 2001;Rybakova et al, 2000), integrins (Carver et al, 1994;McDonald et al, 1995;Terracio et al, 1989), α-actinin (Danowski et al, 1992), talin (Belkin et al, 1986), ankyrin (Nelson and Lazarides, 1983) and desmin (Tidball, 1992).…”