title: Laminin α2-mediated focal adhesion kinase activation triggers Alport glomerular pathogenesis.
abstract: It has been known for some time that laminins containing α1 and α2 chains, which are normally restricted to the mesangial matrix, accumulate in the glomerular basement membranes (GBM) of Alport mice, dogs, and humans. We show that laminins containing the α2 chain, but not those containing the α1 chain activates focal adhesion kinase (FAK) on glomerular podocytes in vitro and in vivo. CD151-null mice, which have weakened podocyte adhesion to the GBM rendering these mice more susceptible to biomechanical strain in the glomerulus, also show progressive accumulation of α2 laminins in the GBM, and podocyte FAK activation. Analysis of glomerular mRNA from both models demonstrates significant induction of MMP-9, MMP-10, MMP-12, MMPs linked to GBM destruction in Alport disease models, as well as the pro-inflammatory cytokine IL-6. SiRNA knockdown of FAK in cultured podocytes significantly reduced expression of MMP-9, MMP-10 and IL-6, but not MMP-12. Treatment of Alport mice with TAE226, a small molecule inhibitor of FAK activation, ameliorated fibrosis and glomerulosclerosis, significantly reduced proteinuria and blood urea nitrogen levels, and partially restored GBM ultrastructure. Glomerular expression of MMP-9, MMP-10 and MMP-12 mRNAs was significantly reduced in TAE226 treated animals. Collectively, this work identifies laminin α2-mediated FAK activation in podocytes as an important early event in Alport glomerular pathogenesis and suggests that FAK inhibitors, if safe formulations can be developed, might be employed as a novel therapeutic approach for treating Alport renal disease in its early stages.
authors.affiliation: Department of Genetics, Boys Town National Research Hospital, Omaha, Nebraska, United States of America.
authors.forename: Duane
authors.initials: D
authors.lastname: Delimont
authors.affiliation: Department of Genetics, Boys Town National Research Hospital, Omaha, Nebraska, United States of America.
authors.forename: Brianna M
authors.initials: BM
authors.lastname: Dufek
authors.affiliation: Department of Genetics, Boys Town National Research Hospital, Omaha, Nebraska, United States of America.
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Meehan
authors.affiliation: Department of Genetics, Boys Town National Research Hospital, Omaha, Nebraska, United States of America.
authors.forename: Marisa
authors.initials: M
authors.lastname: Zallocchi
authors.affiliation: Department of Otolaryngology, Saint Louis University, Saint Louis, Missouri, United States of America.
authors.forename: Michael Anne
authors.initials: MA
authors.lastname: Gratton
authors.affiliation: Department of Otolaryngology, Saint Louis University, Saint Louis, Missouri, United States of America.
authors.forename: Grady
authors.initials: G
authors.lastname: Phillips
authors.affiliation: Department of Genetics, Boys Town National Research Hospital, Omaha, Nebraska, United States of America; Department of Biochemistry, University of Nebraska Medical Center, Omaha, Nebraska, United States of America.
authors.forename: Dominic
authors.initials: D
authors.lastname: Cosgrove
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000187:drug effects; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D050533:Glomerular Basement Membrane / Q000187:drug effects / Q000201:enzymology / Q000473:pathology / Q000648:ultrastructure; D020672:I-kappa B Proteins / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D007700:Kinetics; D007797:Laminin / Q000378:metabolism*; D020782:Matrix Metalloproteinases / Q000378:metabolism; D018345:Mice, Knockout; D009025:Morpholines / Q000494:pharmacology / Q000627:therapeutic use; D000072000:NF-KappaB Inhibitor alpha; D009394:Nephritis, Hereditary / Q000188:drug therapy / Q000201:enzymology* / Q000209:etiology* / Q000473:pathology; D050199:Podocytes / Q000201:enzymology / Q000473:pathology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000378:metabolism; D060185:Tetraspanin 24 / Q000378:metabolism
chemical_list: D020672:I-kappa B Proteins; D015850:Interleukin-6; D007797:Laminin; D009025:Morpholines; C000606204:NFKBIA protein, human; C000606205:Nfkbia protein, mouse; D047428:Protein Kinase Inhibitors; D034741:RNA, Small Interfering; C524632:TAE226; D060185:Tetraspanin 24; C102645:laminin alpha 2; D000072000:NF-KappaB Inhibitor alpha; C084098:laminin A; D051416:Focal Adhesion Protein-Tyrosine Kinases; D020782:Matrix Metalloproteinases