title: Tankyrase inhibition aggravates kidney injury in the absence of CD2AP.
abstract: Inappropriate activation of the Wnt/β-catenin pathway has been indicated in podocyte dysfunction and injury, and shown to contribute to the development and progression of nephropathy. Tankyrases, multifunctional poly(ADP-ribose) polymerase (PARP) superfamily members with features of both signaling and cytoskeletal proteins, antagonize Wnt/β-catenin signaling. We found that tankyrases interact with CD2-associated protein (CD2AP), a protein essential for kidney ultrafiltration as CD2AP-knockout (CD2AP-/-) mice die of kidney failure at the age of 6-7 weeks. We further observed that tankyrase-mediated total poly-(ADP-ribosyl)ation (PARylation), a post-translational modification implicated in kidney injury, was increased in mouse kidneys and cultured podocytes in the absence of CD2AP. The data revealed increased activity of β-catenin, and upregulation of lymphoid enhancer factor 1 (LEF1) (mediator of Wnt/β-catenin pathway) and fibronectin (downstream target of Wnt/β-catenin) in CD2AP-/- podocytes. Total PARylation and active β-catenin were reduced in CD2AP-/- podocytes by tankyrase inhibitor XAV939 treatment. However, instead of ameliorating podocyte injury, XAV939 further upregulated LEF1, failed to downregulate fibronectin and induced plasminogen activator inhibitor-1 (PAI-1) that associates with podocyte injury. In zebrafish, administration of XAV939 to CD2AP-depleted larvae aggravated kidney injury and increased mortality. Collectively, the data reveal sustained activation of the Wnt/β-catenin pathway in CD2AP-/- podocytes, contributing to podocyte injury. However, we observed that inhibition of the PARylation activity of tankyrases in the absence of CD2AP was deleterious to kidney function. This indicates that balance of the PARylation activity of tankyrases, maintained by CD2AP, is essential for normal kidney function. Furthermore, the data reveal that careful contemplation is required when targeting Wnt/β-catenin pathway to treat proteinuric kidney diseases associated with impaired CD2AP.
authors.affiliation: Department of Pathology, University of Helsinki, Helsinki, Finland.
authors.forename: S
authors.initials: S
authors.lastname: Kuusela
authors.affiliation: Department of Pathology, University of Helsinki, Helsinki, Finland.
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Pathology, University of Helsinki, Helsinki, Finland.
authors.forename: A A
authors.initials: AA
authors.lastname: Wasik
authors.affiliation: HHMI/Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA.
authors.forename: H
authors.initials: H
authors.lastname: Suleiman
authors.affiliation: Department of Pathology, University of Helsinki, Helsinki, Finland.
authors.forename: S
authors.identifier: 0000-0003-4189-2415
authors.initials: S
authors.lastname: Lehtonen
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000172:deficiency / Q000235:genetics*; D000818:Animals; D002461:Cell Line, Transformed; D003598:Cytoskeletal Proteins / Q000172:deficiency / Q000235:genetics*; D004625:Embryo, Nonmammalian; D005353:Fibronectins / Q000235:genetics / Q000378:metabolism; D005804:Genes, Lethal; D057809:HEK293 Cells; D006575:Heterocyclic Compounds, 3-Ring / Q000494:pharmacology; D006801:Humans; D051821:Lymphoid Enhancer-Binding Factor 1 / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D050199:Podocytes / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D011064:Poly Adenosine Diphosphate Ribose / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D051381:Rats; D017207:Rats, Sprague-Dawley; D051437:Renal Insufficiency / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D058258:Serpin E2 / Q000819:agonists / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D038501:Tankyrases / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D015027:Zebrafish; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C114545:CD2-associated protein; C495267:CTNNB1 protein, mouse; D003598:Cytoskeletal Proteins; D005353:Fibronectins; D006575:Heterocyclic Compounds, 3-Ring; C497574:Lef1 protein, mouse; D051821:Lymphoid Enhancer-Binding Factor 1; D058258:Serpin E2; C511869:Serpine2 protein, mouse; C544261:XAV939; D051176:beta Catenin; D011064:Poly Adenosine Diphosphate Ribose; D038501:Tankyrases; C498822:Tnks protein, mouse; C511054:tankyrase-2, mouse