title: Role of extracellular matrix renal tubulo-interstitial nephritis antigen (TINag) in cell survival utilizing integrin (alpha)vbeta3/focal adhesion kinase (FAK)/phosphatidylinositol 3-kinase (PI3K)/protein kinase B-serine/threonine kinase (AKT) signaling pathway.
abstract: Tubulo-interstitial nephritis antigen (TINag) is an extracellular matrix protein expressed in tubular basement membranes. Combined mutations in TINag and nephrocystin-1 genes lead to nephronophthisis with reduced cell survival. Because certain extracellular matrix proteins are known to modulate cell survival, studies were initiated in Lewis rats lacking TINag to assess if they are more susceptible to cisplatin-induced injury. Cisplatin induced a higher degree of tubular cell damage and apoptosis in regions where TINag is expressed in a parental Wistar strain. This was accompanied by an accentuated increase in serum creatinine and Kim-1 RNA and renal expression of Bax, p53, and its nuclear accumulation, mtDNA fragmentation, and a decrease of Bcl-2. Cisplatin induced fulminant apoptosis of HK-2 cells with increased caspase3/7 activity, mtDNA fragmentation, and a reduced cell survival. These effects were partially reversed in cells maintained on TINag substratum. Far Western/solid phase assays established TINag binding with integrin αvβ3 comparable with vitronectin. Transfection of cells with αv-siRNA accentuated cisplatin-induced apoptosis, aberrant translocation of cytochrome c and Bax, and reduced cell survival. The αv-siRNA decreased expression of integrin-recruited focal adhesion kinase (FAK) and p-FAK, while increasing the expression of p53 and p-p53. Similarly, p-AKT was reduced although ILK was unaffected. Inhibition of PI3K had similar adverse cellular effects. These effects were ameliorated in cells on TINag substratum. In vivo, a higher degree of decrease in the expression of p-FAK and pAKT was observed in Lewis rats following cisplatin treatment. These in vivo and in vitro studies demonstrate an essential role of TINag in cellular survival to maintain proper tubular homeostasis utilizing integrin αvβ3 and downstream effectors.
authors.affiliation: Department of Pathology and Medicine, Northwestern University, Chicago, Illinois 60611, USA.
authors.forename: Ping
authors.initials: P
authors.lastname: Xie
authors.forename: Vinay K
authors.initials: VK
authors.lastname: Kondeti
authors.forename: Sun
authors.initials: S
authors.lastname: Lin
authors.forename: Yoshisuke
authors.initials: Y
authors.lastname: Haruna
authors.forename: Kirtee
authors.initials: K
authors.lastname: Raparia
authors.forename: Yashpal S
authors.initials: YS
authors.lastname: Kanwar
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000009:adverse effects / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D053179:Caspase 7 / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D002945:Cisplatin / Q000009:adverse effects / Q000494:pharmacology; D045304:Cytochromes c / Q000235:genetics / Q000378:metabolism; D005109:Extracellular Matrix / Q000235:genetics / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism*; D051417:Focal Adhesion Kinase 1 / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D050533:Glomerular Basement Membrane / Q000378:metabolism*; D039302:Integrin alphaVbeta3 / Q000235:genetics / Q000378:metabolism*; D007674:Kidney Diseases / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011917:Rats, Inbred Lew; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013045:Species Specificity; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; C494828:Bax protein, rat; D016326:Extracellular Matrix Proteins; D039302:Integrin alphaVbeta3; C568075:TINag protein, rat; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D045304:Cytochromes c; D019869:Phosphatidylinositol 3-Kinases; D051417:Focal Adhesion Kinase 1; C496052:Ptk2 protein, rat; D051057:Proto-Oncogene Proteins c-akt; C505410:Casp3 protein, rat; D053148:Caspase 3; D053179:Caspase 7; D002945:Cisplatin