Cell-matrix interactions in the glomerular mesangium

Specific interactions between cells and components of the surrounding extracellular matrix (ECM) or underlying basement membrane have been shown to modulate cell behavior, including cellular responses to soluble regulator molecules. In addition to the long-recognized role of such interactions in cell localization, anchoring and differentiation during embryogenesis, they are also involved in diverse processes such as maintenance of tissue integrity, response of cells to mechanical stress, inflammatory response, wound healing, tumor cell growth and metastasis as well as apoptosis. Over the last several years, evidence has been reported that extensive ''cross-talk'' between glomerular mesangial cells (MCs), ECM molecules and soluble mediator substances also affects the proliferative and synthetic phenotype of MCs. This is likely to be relevant for the behavior of MCs during embryonic development, tissue repair and disease processes of glomeruli. The potential biologic and clinical relevance of cell-matrix interactions in the glomerulus makes their elucidation a challenging goal in current kidney research. In this brief review, we present selected aspects of recent investigations concerning the mesangial matrix and its interactions with MCs. In addition to results from cell culture studies, descriptive findings on abnormalities of the ECM and their potential role for the altered MC behavior in glomerular disease will also be discussed.