Extracellular matrix and integrin composition of the normal bladder wall

Abstract

We performed an immunohistochemistry study of the normal human bladder so as to understand the interactions of extracellular matrix (ECM) components and the integrins of cell adhesion that accommodate the volume changes and maintain an impermeable barrier to reabsorption of urine in the bladder. The normal human urothelial cell and/or its plasma membrane contained integrins 0~3, c~V, [31, and [34 but did not contain integrin [33. The urothelial basement membrane (UBM) contained collagen type IV and laminin. Fibronectin and integrins (x3 and [~4 were found in or near the U B M area, with types I and III collagen and tenascin abutting the area. The patterns of collagen, laminin, tenascin, vitronectin, fobronectin, and the 0~3, c~V, [31, and [33 integrins in the lamina propria, vessels, nerves, and smooth-muscle layers are described. These findings detail the normal anatomical ECM/integrin relationship that provides the cellular basis for bladder-wall relationships responsible for its impermeable state and other functions.The relationship of the cellular adhesion mechanisms that help secure the urothelial cells to one another as well as to the underlying urothelial basement membrane (UBM) and extracellular matrix (ECM) components would be expected to contribute to the integrity of the impermeable bladder surface. This adhesion involves a family of celladhesion receptors called integrins, heterodimeric molecules expressed on cell surfaces [3]. The family is composed of at least 13 c~ chains and 8 [3 chains which, depending upon pairing, form heterodimers that recognize one or more ligands present on E C M or on opposing cell surfaces. Only limited information is known about the nature of the integrins or their E C M ligands that perform as the adhesion molecules in the bladder wall.The bladder wall of patients with interstitial cystitis, as characterized by varying degrees of chronic inflammaCorrespondence to:

Expression in bladder transitional cell carcinoma by real‐time quantitative reverse transcription polymerase chain reaction array of 65 genes at the tumor suppressor locus 9q34.1‐2: Identification of 5 candidates tumor suppressor genes

“…Laminins, heterotrimeric molecules composed of an ␣, a ␤ and ␥ ␣ chain (␣2␤1␥3 for laminin-12), are the major noncollagenous constituent of basement membranes and have important functional roles in development and in stabilizing epithelial structures. 17,18 The ␥3 chain is highly tissue-and cell-specific, being significantly expressed in capillaries and arterioles of kidney, in interstitial Leydig cells of testis, and in normal bladder urothelial cells as also reported in this study. Loss of laminin in the extracellular matrix was also found to be an early event in primary ovarian tumors, suggesting that alteration of the basement membrane was implicated in the early transformation of ovarian surface epithelium.…”

Gene Expression in the Urinary Bladder

“…Among the genes with higher expression in TCC without adjacent CIS were the LAMB3 and ITGB4 genes, which encode proteins involved in cell adhesion (25). This group also contained the UPK2 gene, which encodes the bladder-specific uroplakin 2 protein.…”

Fibronectin 1 protein expression in clear cell renal cell carcinoma

“…The molecule is widely distributed in healthy membranes, lamina propria, vessel structures, nerves and smooth-muscle cell layers (3). However, the function of FN is not clearly known (4,5).…”