30 research outputs found

    Mitotic cell cycle proteins increase in podocytes despite lack of proliferation

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    Mitotic cell cycle proteins increase in podocytes despite lack of proliferation.BackgroundPodocyte proliferation is an uncommon response to glomerular injury and its lack may underlie the development of glomerulosclerosis. However, whether podocytes have the capacity to enter and finish mitosis and cytokinesis is not known.MethodsThe expression of mitotic cell cycle proteins (phosphorylated Histone 3, Cdc2, cyclin B1 and B2) was examined by immunohistochemistry in kidneys of embryonal mice, transgenic HIV-mice, and rats with experimental membranous nephropathy (passive Heymann nephritis, PHN). Mitotic proteins also were measured by Western blot in glomerular protein from PHN-rats and the activity of mitotic cyclins was quantified by histone kinase assay.ResultsMitotic proteins were increased in embryonal mouse glomeruli during the S- and comma-shaped stages and were absent at the capillary loop stage and in mature rodent glomeruli. There was an increase in podocyte expression of Cdc2, cyclin B1 and B2 and phosphorylated histone 3 in PHN rats, and in HIV transgenic mice.ConclusionsPodocytes have the ability to increase cell cycle proteins required for mitosis. Without obvious differences in the expression of the major mitotic proteins in PHN- and HIV-nephropathy, a regulatory disturbance in cytokinesis might be responsible for the development of polynucleated cells and a lack of podocyte proliferation in experimental glomerular disease

    Polymerase chain reaction and focal contact formation indicate integrin expression in mesangial cells

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    Polymerase chain reaction and focal contact formation indicate integrin expression in mesangial cells. Cultured kidney glomerular mesangial cells (MCs) allow the role of extracellular matrix (ECM) and growth factors in glomerular inflammatory disease to be studied. To investigate the potential of MCs to interact with matrix components, the expression of integrin mRNA in cultured MCs was examined by polymerase chain reaction (PCR), by Northern blotting and by immunofluorescence. In addition, the effect of matrix substrates on mRNA expression was assessed by PCR. Northern blots with cDNA probes to integrin α-chains revealed that MCs expressed α1, α3 and α5 integrin mRNA. α1 and α3 were the major messages. No α2, α4 or α6 were detectable. RT-PCR revealed that α2 and α6 were also expressed at low levels. The control cells, HT1080, expressed α2, α3, α4, α5 and α6 mRNA, and Rugli expressed α1, α3, and α5, supporting previous studies. Immunocytochemistry confirmed that α1β1, α2β1, α3β1 and α5β1 integrins were expressed and that they were concentrated into focal adhesions (α1β1 on type I collagen and laminin; α2β1 on type I collagen; α3β1 on type I collagen, laminin and fibronectin; α5β1 on fibronectin). α6β1 was not detected in focal contacts. Attachment, spreading, and formation of talin and integrin containing focal contacts still occurred when endogenous protein synthesis was blocked with 30 µg · ml-1 cycloheximide. Variation of substrate did not lead to a rapid degradation of integrin α-chain mRNA as assessed by RT-PCR. These results provide a basis for studying the regulation of interactions between MCs and extracellular matrix mediated by integrins

    За кадры. 1952. № 12 (559)

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    Смотр молодых талантов"Бороться и искать, найти и не сдаваться!" / Е. ОдоевскаяУсловия социалистического соревнования общежитий Томского политехнического института / А. А. Воробьев [и др.
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