title: Decreases in podocin, CD2-associated protein (CD2AP) and tensin2 may be involved in albuminuria during septic acute renal failure.
abstract: Podocytes have a peculiar structure constituting slit diaphragm (SD) and foot process (FP), and play essential roles in the glomerular filtration barrier. There is now ample evidence that SD- and FP-associated molecules, such as podocin and CD2-associated protein (CD2AP), are down-regulated during albuminuria of chronic kidney disease. However, it is still unclear whether these molecules are altered during acute renal failure (ARF) with albuminuria. Using lipopolysaccharide (LPS)-treated mice as a model of septic ARF, we provide evidence that the expression of SD- and FP-associated molecules becomes faint, along with albuminuria. In the LPS-treated mice, urinary albumin levels gradually increased, associated with the elevation of blood urea nitrogen levels, indicating the successful induction of albuminuria during septic ARF. In this pathological process, glomerular podocin expression became faint, especially at 36 hr post-LPS challenge (i.e., a peak of albuminuria). Likewise, LPS treatment led to a significant decrease in CD2AP, an anchorage between podocin and F-actin. With regard to this, tensin2 is a novel molecule that stabilizes F-actin extension. Interestingly, glomerular tensin2 expression levels were also decreased during the albuminuric phase, associated with losses of glomerular F-actin and synaptopodin under septic states. As a result, there were some lesions of podocytic FP effacement, as shown by electron microscopy. Based on these data, we emphasize the importance of concomitant decreases in podocin, CD2AP and tensin2 during septic ARF-associated proteinuria.
authors.affiliation: Division of Molecular Regenerative Medicine, Department of Biochemistry and Molecular Biology, Osaka University Graduate School of Medicine, Suita, Osaka 565–0871, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kato
authors.forename: Yoko
authors.initials: Y
authors.lastname: Mizuno-Horikawa
authors.forename: Shinya
authors.initials: S
authors.lastname: Mizuno
mesh_terms: D058186:Acute Kidney Injury / Q000209:etiology*; D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000419:Albuminuria / Q000209:etiology*; D000818:Animals; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000633:toxicity; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D050199:Podocytes / Q000502:physiology / Q000648:ultrastructure; D018805:Sepsis / Q000150:complications*; D000070876:Tensins
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C114545:CD2-associated protein; D003598:Cytoskeletal Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008070:Lipopolysaccharides; D008565:Membrane Proteins; C407223:NPHS2 protein; D000070876:Tensins; D010749:Phosphoprotein Phosphatases; C511707:Tns2 protein, mouse