Regulation of cell adhesion and migration in lens development

Abstract

Cell movements during lens development and differentiation involve dynamic regulation of cell-matrix and cell-cell adhesion. How these processes are regulated depends on the particular array of matrix components and adhesion proteins that are expressed, as well as the signaling pathways that affect them. This review examines what is known about adhesion proteins and their regulation in the lens in light of recent findings about the mechanism of cell migration. The characteristic shape and organization of the lens depends on highly regulated cell movements during development and differentiation. Epithelial cells at the equator migrate posteriorly, bringing them into contact with factors in the vitreous humor and initiating differentiation. Elongation of the differentiating fiber cells is coupled with directed migration, posteriorly along the capsule and anteriorly along the fiber cell-epithelial interface, to generate a symmetrically organized fiber cell mass with aligned suture planes. To make these movements, cells systematically create and dissolve cell-cell and cell-matrix adhesions, form connections between these adhesions and the cytoskeleton, and generate contractile force. Since errors in cell migration may lead to aberrant lens shape or misplacement of the lens sutures, precise regulation of each step is essential for the optical quality of the lens. Recent advances in cellular developmental biology have begun to shed light on the molecular mechanisms underlying cell movements and the changes in adhesion that make them possible. This review will summarize those findings and relate them to relevant studies of the lens to provide an outline of the cellular events that lead to lens morphogenesis.

GAD isoforms exhibit distinct spatiotemporal expression patterns in the developing mouse lens: Correlation with Dlx2 and Dlx5

“…The progress from epithelial to terminally differentiated fiber cells proceeds through well-defined stages characterized by the synthesis of specific sets of intermediate filament proteins (Blankenship et al, 2001), adhesion molecules (Beebe et al, 2001;Zelenka, 2004), and lens crystallins (␣, ␤, ␥, ␦). The latter account for the bulk of lens protein and provide the lens transparency (Piatigorsky, 1981(Piatigorsky, , 1989Bloemendal et al, 1989Bloemendal et al, , 2004Bhat, 2003).…”

Equarin is involved in cell adhesion by means of heparan sulfate proteoglycan during lens development

“…During lens differentiation, epithelial cells undergo vertical elongation, with the anterior and posterior tips of the elongating fiber cells sliding along the epithelium and capsule, respectively, as these cells migrate inward. These cellular processes are highly coordinated through cell adhesive interactions, actin cytoskeletal reorganization and contractile force generation (Piatigorsky, 1981;Taylor et al, 1996;Bassnett et al, 1999;Kuszak et al, 2004;Zelenka, 2004). The ability of a cell to recognize and interact with specific extracellular matrix (ECM) components is a fundamental requirement for cell migration and differentiation.…”

Development of a device to stretch tissue-like materials and to measure their mechanical properties by scanning probe microscopy

“…For example, this force is involved in physiological processes such as cellular migration [4], proliferation [5], and differentiation [6]. The activities of these physiological processes are strongly influenced by external loading forces [7][8][9].…”