Betaig-h3 (betaig-h3) is a secretory protein composed of fasciclin I-like repeats containing sequences that allows binding of integrins and glycosaminoglycans in vivo. Expression of betaig-h3 is responsive to TGF-beta and the protein is found to be associated with extracellular matrix (ECM) molecules, implicating betaig-h3 as an ECM adhesive protein of developmental processes. We previously observed predominant expression of betaig-h3 expression in the basement membrane of proximal tubules of kidney. In this study, the physiological relevance of such localized expression of betaig-h3 was examined in the renal proximal tubular epithelial cells (RPTEC). RPTEC constitutively expressed betaig-h3 and the expression was dramatically induced by exogenous TGF-beta1 treatment. betaig-h3 and its second and fourth FAS1 domain were able to mediate RPTEC adhesion, spreading and migration. Two known alpha3beta1 integrin-interaction motifs including aspartatic acid and isoleucine residues, NKDIL and EPDIM in betaig-h3 were responsible to mediate RPTEC adhesion, spreading, and migration. By using specific antibodies against integrins, we confirmed that alpha3beta1 integrin mediates the adhesion and migration of RPTECs on betaig-h3. In addition, it also enhanced proliferation of RPTECs through NKDIL and EPDIM. These results indicate that betaig-h3 mediates adhesion, spreading, migration and proliferation of RPTECs through the interaction with alpha3beta1 integrin and is intimately involved in the maintenance and the regeneration of renal proximal tubular epithelium.
Amino Acid Motifs ; Antibodies, Blocking/immunology ; Cell Adhesion/physiology ; Cell Movement/physiology ; Cell Proliferation ; Cells, Cultured ; Epithelial Cells/drug effects ; Extracellular Matrix Proteins/chemistry/immunology/*metabolism ; Humans ; Integrin alpha3beta1/chemistry/immunology/*metabolism ; Kidney Tubules, Proximal/cytology/metabolism/*physiology ; Peptides/chemistry/metabolism ; Protein Interaction Mapping ; Research Support, Non-U.S. Gov't ; Transforming Growth Factor beta/chemistry/immunology/*metabolism/pharmacology

OBJECTIVETo observe the preventive effect of multi-glycoside of Tripterygium Wilfordii Hook. f. (GYW) on proteinuria and mesentery injury in experimental mesangial proliferative glomerulonephritis in vivo.

METHODSThe reversible anti-Thyl.1 antibody glomerulo nephritis model of rats was established with monoclonal antibody 1-22-3 and intervened with GTW, and a control group was set up in the same time. Changes of 24h urinary protein excretion, serum creatinine (Scr), blood urea nitrogen (BUN), total plasma protein (TP) and glomerular morphology were observed, and the level of mRNA expression of proliferative factors, including platelet-derived growth factor-BB (PDGF-BB) and transforming growth factor-beta (TGF-beta), in renal tissue was determined.

RESULTSGTW could inhibit proteinuria and mesangial injury in anti-Thyl. 1 antibody nephritis model. The PDGF-BB and TGF-beta mRNA expression in the anti-Thy1.1 antibody nephritis model rats were increased for 2.84 and 1.64 times respectively to those in the normal control group. GTW could down-regulate the over-expression of PDGF-BB mRNA by 33.1%, it was significantly different to that in the control group (P < 0.05).

CONCLUSIONGTW could reduce the proteinuria and inhibit mesangial cells proliferation and extracellular matrix deposition, these effects maybe related to the down-regulating of PDGF-BB mRNA expression.

Animals ; Antibodies, Monoclonal ; immunology ; Drugs, Chinese Herbal ; therapeutic use ; Female ; Glomerular Mesangium ; pathology ; Glomerulonephritis, Membranoproliferative ; chemically induced ; metabolism ; prevention & control ; Glycosides ; isolation & purification ; pharmacology ; therapeutic use ; Phytotherapy ; Plant Extracts ; therapeutic use ; Platelet-Derived Growth Factor ; biosynthesis ; genetics ; Proteinuria ; prevention & control ; Proto-Oncogene Proteins c-sis ; Random Allocation ; Rats ; Rats, Wistar ; Thy-1 Antigens ; immunology ; Transforming Growth Factor beta ; biosynthesis ; genetics ; Tripterygium ; chemistry