LMX1B is essential for the maintenance of differentiated podocytes in adult kidneys
| Autor: | Joachim Wegener, Mathias Gorski, Marion Kubitza, Markus Moser, Claudio Lottaz, Uwe de Vries, Iris M. Heid, Eric Rivera-Milla, Richard Warth, Tillmann Burghardt, Jürgen Kastner, Anne Rascle, Helga Schmidt, Christoph Englert, Hani Suleiman, Carsten A. Böger, Natalya Stepanova, Ralph Witzgall, Jeffrey B. Kopp, Rainer Spang, Irmgard Hertting, Sarah M. Schmidt, Claudia Tanja Mierke |
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| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
Collagen Type IV
Aging medicine.medical_specialty LIM-Homeodomain Proteins Apoptosis Podocyte foot Actin cytoskeleton organization Podocyte Nephrin Mice Nail-Patella Syndrome Internal medicine medicine Animals Zebrafish Oligonucleotide Array Sequence Analysis biology Podocytes Intracellular Signaling Peptides and Proteins Membrane Proteins Cell Differentiation General Medicine Actin cytoskeleton Actins Cell biology Mice Inbred C57BL Proteinuria Basic Research Endocrinology medicine.anatomical_structure Nephrology Knockout mouse Slit diaphragm biology.protein Chromatin immunoprecipitation Transcription Factors |
| Zdroj: | J. Am. Soc. Nephrol. 24, 1830-1848 (2013) |
| Popis: | Mutations of the LMX1B gene cause nail-patella syndrome, a rare autosomal-dominant disorder affecting the development of the limbs, eyes, brain, and kidneys. The characterization of conventional Lmx1b knockout mice has shown that LMX1B regulates the development of podocyte foot processes and slit diaphragms, but studies using podocyte-specific Lmx1b knockout mice have yielded conflicting results regarding the importance of LMX1B for maintaining podocyte structures. In order to address this question, we generated inducible podocyte-specific Lmx1b knockout mice. One week of Lmx1b inactivation in adult mice resulted in proteinuria with only minimal foot process effacement. Notably, expression levels of slit diaphragm and basement membrane proteins remained stable at this time point, and basement membrane charge properties also did not change, suggesting that alternative mechanisms mediate the development of proteinuria in these mice. Cell biological and biophysical experiments with primary podocytes isolated after 1 week of Lmx1b inactivation indicated dysregulation of actin cytoskeleton organization, and time-resolved DNA microarray analysis identified the genes encoding actin cytoskeleton-associated proteins, including Abra and Arl4c, as putative LMX1B targets. Chromatin immunoprecipitation experiments in conditionally immortalized human podocytes and gel shift assays showed that LMX1B recognizes AT-rich binding sites (FLAT elements) in the promoter regions of ABRA and ARL4C, and knockdown experiments in zebrafish support a model in which LMX1B and ABRA act in a common pathway during pronephros development. Our report establishes the importance of LMX1B in fully differentiated podocytes and argues that LMX1B is essential for the maintenance of an appropriately structured actin cytoskeleton in podocytes. |
| Databáze: | OpenAIRE |
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