title: Extracellular purines' action on glomerular albumin permeability in isolated rat glomeruli: insights into the pathogenesis of albuminuria.
abstract: Purinoceptors (adrengeric receptors and P2 receptors) are expressed on the cellular components of the glomerular filtration barrier, and their activation may affect glomerular permeability to albumin, which may ultimately lead to albuminuria, a well-established risk factor for the progression of chronic kidney disease and development of cardiovascular diseases. We investigated the mechanisms underlying the in vitro and in vivo purinergic actions on glomerular filter permeability to albumin by measuring convectional albumin permeability (Palb) in a single isolated rat glomerulus based on the video microscopy method. Primary cultured rat podocytes were used for the analysis of Palb, cGMP accumulation, PKG-Iα dimerization, and immunofluorescence. In vitro, natural nucleotides (ATP, ADP, UTP, and UDP) and nonmetabolized ATP analogs (2-meSATP and ATP-γ-S) increased Palb in a time- and concentration-dependent manner. The effects were dependent on P2 receptor activation, nitric oxide synthase, and cytoplasmic guanylate cyclase. ATP analogs significantly increased Palb, cGMP accumulation, and subcortical actin reorganization in a PKG-dependent but nondimer-mediated route in cultured podocytes. In vivo, 2-meSATP and ATP-γ-S increased Palb but did not significantly affect urinary albumin excretion. Both agonists enhanced the clathrin-mediated endocytosis of albumin in podocytes. A product of adenine nucleotides hydrolysis, adenosine, increased the permeability of the glomerular barrier via adrenergic receptors in a dependent and independent manner. Our results suggest that the extracellular nucleotides that stimulate an increase of glomerular Palb involve nitric oxide synthase and cytoplasmic guanylate cyclase with actin reorganization in podocytes.
authors.affiliation: Department of Therapy Monitoring and Pharmacogenetics, Medical University of Gdansk, Gdansk, Poland;
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Kasztan
authors.affiliation: Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Centre Polish Academy of Sciences, Gdansk, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Piwkowska
authors.affiliation: Department of Therapy Monitoring and Pharmacogenetics, Medical University of Gdansk, Gdansk, Poland;
authors.forename: Ewelina
authors.initials: E
authors.lastname: Kreft
authors.affiliation: Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Centre Polish Academy of Sciences, Gdansk, Poland.
authors.forename: Dorota
authors.initials: D
authors.lastname: Rogacka
authors.affiliation: Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Centre Polish Academy of Sciences, Gdansk, Poland.
authors.forename: Irena
authors.initials: I
authors.lastname: Audzeyenka
authors.affiliation: Department of Therapy Monitoring and Pharmacogenetics, Medical University of Gdansk, Gdansk, Poland;
authors.forename: Mirosława
authors.initials: M
authors.lastname: Szczepanska-Konkel
authors.affiliation: Department of Clinical Chemistry, Medical University of Gdansk, Gdansk, Poland; and Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Centre Polish Academy of Sciences, Gdansk, Poland majank@gumed.edu.pl.
authors.forename: Maciej
authors.initials: M
authors.lastname: Jankowski
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D000418:Albumins / Q000378:metabolism*; D000419:Albuminuria / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D006152:Cyclic GMP / Q000378:metabolism; D004705:Endocytosis / Q000187:drug effects; D005260:Female; D006162:Guanylate Cyclase / Q000096:biosynthesis; D066298:In Vitro Techniques; D007678:Kidney Glomerulus / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D010539:Permeability / Q000187:drug effects; D050199:Podocytes / Q000187:drug effects / Q000378:metabolism; D061251:Primary Cell Culture; D058910:Purinergic P2 Receptor Agonists / Q000494:pharmacology; D011687:Purines / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000418:Albumins; D058910:Purinergic P2 Receptor Agonists; D011687:Purines; D000255:Adenosine Triphosphate; D019001:Nitric Oxide Synthase; D006162:Guanylate Cyclase; D006152:Cyclic GMP
keywords: P2 receptors; albumin; filtration barrier; glomeruli; permeability; podocytes