title: Podocyte Purinergic P2X4 Channels Are Mechanotransducers That Mediate Cytoskeletal Disorganization.
abstract: Podocytes are specialized, highly differentiated epithelial cells in the kidney glomerulus that are exposed to glomerular capillary pressure and possible increases in mechanical load. The proteins sensing mechanical forces in podocytes are unconfirmed, but the classic transient receptor potential channel 6 (TRPC6) interacting with the MEC-2 homolog podocin may form a mechanosensitive ion channel complex in podocytes. Here, we observed that podocytes respond to mechanical stimulation with increased intracellular calcium concentrations and increased inward cation currents. However, TRPC6-deficient podocytes responded in a manner similar to that of control podocytes, and mechanically induced currents were unaffected by genetic inactivation of TRPC1/3/6 or administration of the broad-range TRPC blocker SKF-96365. Instead, mechanically induced currents were significantly decreased by the specific P2X purinoceptor 4 (P2X4) blocker 5-BDBD. Moreover, mechanical P2X4 channel activation depended on cholesterol and podocin and was inhibited by stabilization of the actin cytoskeleton. Because P2X4 channels are not intrinsically mechanosensitive, we investigated whether podocytes release ATP upon mechanical stimulation using a fluorometric approach. Indeed, mechanically induced ATP release from podocytes was observed. Furthermore, 5-BDBD attenuated mechanically induced reorganization of the actin cytoskeleton. Altogether, our findings reveal a TRPC channel-independent role of P2X4 channels as mechanotransducers in podocytes.
authors.affiliation: Walther-Straub-Institute of Pharmacology and Toxicology, University of Munich, Munich, Germany;
authors.forename: Anna-Lena
authors.initials: AL
authors.lastname: Forst
authors.affiliation: Walther-Straub-Institute of Pharmacology and Toxicology, University of Munich, Munich, Germany;
authors.forename: Vlad Sorin
authors.initials: VS
authors.lastname: Olteanu
authors.affiliation: INSERM U1163, Laboratory of Hereditary Kidney Diseases, Imagine Institute, Paris, France;
authors.forename: Géraldine
authors.initials: G
authors.lastname: Mollet
authors.affiliation: Division of Pediatric Nephrology, Heidelberg University Center for Pediatrics and Adolescent Medicine, Heidelberg, Germany;
authors.forename: Tanja
authors.initials: T
authors.lastname: Wlodkowski
authors.affiliation: Division of Pediatric Nephrology, Heidelberg University Center for Pediatrics and Adolescent Medicine, Heidelberg, Germany;
authors.forename: Franz
authors.initials: F
authors.lastname: Schaefer
authors.affiliation: Walther-Straub-Institute of Pharmacology and Toxicology, University of Munich, Munich, Germany;
authors.forename: Alexander
authors.initials: A
authors.lastname: Dietrich
authors.affiliation: Department of Medicine, Rush University Medical Center, Chicago, Illinois; and.
authors.forename: Jochen
authors.initials: J
authors.lastname: Reiser
authors.affiliation: Walther-Straub-Institute of Pharmacology and Toxicology, University of Munich, Munich, Germany; DZHK (German Centre for Cardiovascular Research), Munich Heart Alliance, Munich, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Gudermann
authors.affiliation: Walther-Straub-Institute of Pharmacology and Toxicology, University of Munich, Munich, Germany; DZHK (German Centre for Cardiovascular Research), Munich Heart Alliance, Munich, Germany mederos@lrz.uni-muenchen.de ursula.storch@lrz.uni-muenchen.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Mederos y Schnitzler
authors.affiliation: Walther-Straub-Institute of Pharmacology and Toxicology, University of Munich, Munich, Germany;
authors.forename: Ursula
authors.initials: U
authors.lastname: Storch
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D001570:Benzodiazepinones / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D002784:Cholesterol / Q000378:metabolism; D003599:Cytoskeleton / Q000648:ultrastructure; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D040542:Mechanotransduction, Cellular / Q000187:drug effects; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D050199:Podocytes / Q000378:metabolism*; D058920:Purinergic P2X Receptor Antagonists / Q000494:pharmacology; D058848:Receptors, Purinergic P2X4 / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D013314:Stress, Mechanical; D050052:TRPC Cation Channels / Q000172:deficiency / Q000235:genetics; D000074287:TRPC6 Cation Channel
chemical_list: C587048:5-(3-bromophenyl)-1,3-dihydro-2H-benzofuro(3,2-e)-1,4-diazepin-2-one; D001570:Benzodiazepinones; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C407223:NPHS2 protein; D058920:Purinergic P2X Receptor Antagonists; D058848:Receptors, Purinergic P2X4; D050052:TRPC Cation Channels; C104603:TRPC3 cation channel; D000074287:TRPC6 Cation Channel; C492146:Trpc6 protein, mouse; C096351:transient receptor potential cation channel, subfamily C, member 1; D000255:Adenosine Triphosphate; D002784:Cholesterol; D002118:Calcium
keywords: cell and transport physiology; cell signaling; glomerulosclerosis