Cloning of mouse integrin alphaV cDNA and role of the alphaV-related matrix receptors in metanephric development.

Abstract

Abstract. Metanephrogenesis has been a long-standing model to study cell-matrix interactions. A number of adhesion molecules, including matrix receptors (i.e., integrins), are believed to be involved in such interactions. The integrins contain a and ~ subunits and are present in various tissues in different heterodimeric forms. In this study, one of the members of the integrin superfamily, av, was characterized, and its relevance in murine nephrogenesis was investigated. Mouse embryonic renal eDNA libraries were prepared and screened for av, and multiple clones were isolated and sequenced. The deduced amino acid sequence of the et v cDNA clones and hydropathic analysis revealed that it has a typical signal sequence and extracellular, transmembrane, and cytoplasmic domains, with multiple Ca 2÷ binding sites. No A(U)nA mRNA instability motifs were present. Conformational analysis revealed no rigid long-range-ordered structure in murine O~v. The O~v was expressed in the embryonic kidney at day 13 of the gestation, with a transcript size of ~7 kb. Its expression increased progressively during the later gestational stages and in the neonatal period. It was distributed in the epithelial elements of developing nephrons and was absent in the uninduced mesenchyme. In mature metanephroi, the expression was relatively high in the glomeruli and blood vessels, as compared to the tubules. Various heterodimeric associations of av, i.e., with [31, [33, [35, and [36, were observed in metanephric tissues. Inclusion of av-antisense-oligodeoxynucleotide or -antibody in metanephric culture induced dysmorphogenesis of the kidney with reduced population of the nephrons, disorganization of the ureteric bud branches, and reduction of mRNA and protein expressions of etv. The expressions of integrin [33, [35, and 136 were unaltered. These findings suggest that the integrin av is developmentally regulated, has a distinct spatio-temporal expression, and is relevant in the mammalian organogenesis.URING development, the interactions between cell adhesion molecules and extraceUular matrix (ECM) 1 glycoproteins are believed to be essential for the morphogenesis of various organs (Hay, 1991;Humphries et al., 1991;Reichardt and Tomaselli, 1991;Ruoslahti, 1991;Toole, 1991;Hynes, 1992;Juliano and Haskill, 1993;Kramer et al., 1993;Gladson and Cheresh, 1994;Hemler et al., 1994;Quaranta et al., 1994). The maturation of the mammalian metanephros constitutes many of the steps which are prototypic of the events relevant to the development of other organ systems (Ekblom, 1993;Clapp and Abrahamson, 1994). The renal organogenesis ensues after an initial reciprocal induction between the metanephric Address all correspondence to Dr. Y.S. Kanwar, Department of Pathology, Northwestern University Medical School, 303 East Chicago Avenue, Chicago, IL 60611. Tel.: (312) 503-0084. Fax: (312) 503-0627.1. Abbreviations used in this paper: ECM, extracellular matrix; ODN, oligodeoxynucleotide; RT, reverse transcriptase. mesenchyme and the ureteric bud, which leads to...

Developmental regulation, expression, and apoptotic potential of galectin-9, a beta-galactoside binding lectin.

“…Analyses were performed on total RNA isolated from various tissues of fetal and adult ICR mice (Harlan Sprague Dawley, Inc., Indianapolis, IN), as described previously (14,35). In brief, 30 g of total RNA of each organ was glyoxalated, subjected to 1% agarose gel electrophoresis, transferred to a nylon membrane (Amersham Corp., Arlington Heights, IL), and hybridized with [ ␣ 32 P]dCTP random-radiolabeled mouse galectin-9 (U55060; Genbank/EMBL/DDBJ) and ␤ -actin cDNAs (M62174; American Type Culture Collection, Rockville, MD) under high stringency conditions.…”

Human Podocytes Adhere to the KRGDS Motif of the α3α4α5 Collagen IV Network

“…This RGD is located in a highly divergent hydrophilic triple helix-NC1 junction 30 and embedded in a five-residue motif KRGDS that undergoes phosphorylation in vivo. 21 Therefore, it is possible that, when this primate-exclusive motif in the native GBM networks undergoes phosphorylation, it becomes accessible to integrin ␣v␤3. 21 It has been shown that phosphorylation of extracellular proteins promotes RGD-mediated cell attachment whereas dephosphorylation inhibits it.…”

“…21 Therefore, it is possible that, when this primate-exclusive motif in the native GBM networks undergoes phosphorylation, it becomes accessible to integrin ␣v␤3. 21 It has been shown that phosphorylation of extracellular proteins promotes RGD-mediated cell attachment whereas dephosphorylation inhibits it. 31 The RGD/phosphorylation motif is targeted by GPBP, a Ser/Thr kinase, which is expressed more abundantly in the human glomerulus than in other mammals that do not contain the RGD/phosphorylation motif.…”

“…18 Although integrins ␣1␤1 and ␣2␤1 are also expressed by podocytes, their role in normal glomerular development is likely to be less significant, as mice null for the ␣1 19 or ␣2 subunit (R. Zent and A. Pozzi, unpublished) only have a minor glomerular phenotype. Although ␣v integrins are expressed on podocytes, 20,21 their role in glomerular development is unknown.…”

Inhibition of angiogenesis in vitro by αv integrin–directed antisense oligonucleotides

“…Secondly, v is expressed on several normal tissues 4 and antisense -mediated down -regulation of v impaired osteoclast function and induced dysmorphogenesis of the kidney. 40,41 Thus, side effects of v inhibitors could be possible. In addition, v integrins are expressed by some invasive tumors such as metastatic melanoma, late -stage glioblastoma, or breast cancer, and are suggested to be crucial in tumor progression.…”