title: Evidence for HSP-mediated cytoskeletal stabilization in mesothelial cells during acute experimental peritoneal dialysis.
abstract: Low biocompatibility of peritoneal dialysis fluid (PDF) injures mesothelial cells and activates their stress response. In this study, we investigated the role of heat shock proteins (HSP), the main cytoprotective effectors of the stress response, in cytoskeletal stabilization of mesothelial cells in experimental peritoneal dialysis. In cultured human mesothelial cells, cytoskeletal integrity was assessed by detergent extractability of marker proteins following in vitro PDF exposure. Effects of HSP on stabilization of ezrin were evaluated by a conditioning protocol (PDF pretreatment) and repair assay, based on coincubation of cytoskeletal protein fractions with recombinant HSP-72 or HSP-72 antibodies. In the rat model, detachment of mesothelial cells from their peritoneal monolayer during in vivo PDF exposure was assessed with and without overexpression of HSP-72 (by heat conditioning). In vitro, cytoskeletal disruption on sublethal PDF exposure was demonstrated by significantly altered detergent extractability of ezrin and ZO-1. Restoration was associated with significant induction and cytoskeletal redistribution of HSP during recovery. Both the conditioning protocol and in vitro repair assay provided evidence for HSP-72-mediated cytoskeletal stabilization. In the rat model, overexpression of HSP-72 following heat conditioning resulted in significantly reduced detachment of mesothelial cells on in vivo exposure to PDF. Our results establish an essential role of HSP in repair and cytoprotection of cytoskeletal integrity in mesothelial cells following acute in vitro and in vivo exposure to PDF. Repeated exposure to PDF, as is the rule in the clinical setting, may not only cause repeat injury to mesothelial cells but rather represents a kind of inadvertent conditioning treatment.
authors.affiliation: Department of Pediatrics, Univ. Kinderklinik Wien, Austria.
authors.forename: Michaela
authors.initials: M
authors.lastname: Endemann
authors.forename: Helga
authors.initials: H
authors.lastname: Bergmeister
authors.forename: Bettina
authors.initials: B
authors.lastname: Bidmon
authors.forename: Michael
authors.initials: M
authors.lastname: Boehm
authors.forename: Dagmar
authors.initials: D
authors.lastname: Csaicsich
authors.forename: Laura
authors.initials: L
authors.lastname: Malaga-Dieguez
authors.forename: Klaus
authors.initials: K
authors.lastname: Arbeiter
authors.forename: Heinz
authors.initials: H
authors.lastname: Regele
authors.forename: Kurt
authors.initials: K
authors.lastname: Herkner
authors.forename: Christoph
authors.initials: C
authors.lastname: Aufricht
mesh_terms: D000199:Actins / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002470:Cell Survival / Q000502:physiology; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000502:physiology*; D003720:Densitometry; D015314:Dialysis Solutions / Q000633:toxicity*; D005455:Fluorescent Antibody Technique; D006360:Heat-Shock Proteins / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D007511:Ischemia / Q000473:pathology; D019194:Ischemic Preconditioning; D007668:Kidney / Q000166:cytology* / Q000187:drug effects; D008297:Male; D010530:Peritoneal Dialysis; D011092:Polyethylene Glycols / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013501:Surface-Active Agents / Q000494:pharmacology
chemical_list: D000199:Actins; D015314:Dialysis Solutions; D006360:Heat-Shock Proteins; D013501:Surface-Active Agents; D011092:Polyethylene Glycols; D000255:Adenosine Triphosphate