Expression of NTPDase1 and NTPDase2 in murine kidney: relevance to regulation of P2 receptor signaling

2005 ◽  
Vol 288 (5) ◽  
pp. F1032-F1043 ◽  
Author(s):  
Bellamkonda K. Kishore ◽  
Jorge Isaac ◽  
Michel Fausther ◽  
Sheryl R. Tripp ◽  
Huihui Shi ◽  
...  
Keyword(s):  
Blood Vessels ◽  
Degradation Products ◽  
Collecting Duct ◽  
Extracellular Nucleotides ◽  
Tubuloglomerular Feedback ◽  
Nucleoside Triphosphate ◽  
Cellular Expression ◽  
Peritubular Capillaries ◽  
Pelvic Wall ◽  
Glomerular Arterioles

The regulation of renal function by extracellular nucleotides encompasses alterations in glomerular hemodynamics, microvascular function, tubuloglomerular feedback, tubular transport, cell growth or apoptosis, and transport of water and solutes in the medullary collecting duct. Nearly all cells can release ATP or other nucleotides that are then rapidly hydrolyzed in the extracellular milieu. However, little information is available on the cellular expression of ectoenzymes that hydrolyze extracellular nucleotides within the kidney. Nucleoside triphosphate diphosphohydrolases (NTPDases) are plasma membrane-bound ectonucleotidases. NTPDase1 has identity with CD39, a B lymphocyte activation marker, and hydrolyzes extracellular ATP and ADP to AMP within the vasculature, whereas NTPDase2/CD39L(ike)1 preferentially converts ATP to ADP outside of blood vessels. Using immunohistochemical and in situ hybridization approaches, we localized the protein and mRNA of NTPDase1 and 2 in murine renal tissues. In the renal cortex, NTPDase1 is expressed by vascular smooth muscle cells and endothelium in interlobular arteries, afferent glomerular arterioles, and peritubular capillaries. In the inner medulla, NTPDase1 is expressed in ascending thin limbs of Henle's loop, ducts of Bellini, and in the pelvic wall. In contrast, NTPDase2 is expressed in Bowman's capsule, glomerular arterioles, adventitia of blood vessels, and pelvic wall. Thus the distribution patterns of NTPDases have parallels to the known distribution of P2 receptors within the kidney. NTPDases may modulate regulatory effects of ATP and degradation products within the vasculature and other sites and thereby potentially influence physiological as well as multiple pathological events in the kidney.

scholarly journals Extracellular Nucleotides and P2 Receptors in Renal Function

2020 ◽  
Vol 100 (1) ◽  
pp. 211-269 ◽  
Author(s):  
Volker Vallon ◽  
Robert Unwin ◽  
Edward W. Inscho ◽  
Jens Leipziger ◽  
Bellamkonda K. Kishore
Keyword(s):  
Blood Flow ◽  
Fluid Transport ◽  
Collecting Duct ◽  
Extracellular Nucleotides ◽  
Tubuloglomerular Feedback ◽  
P2 Receptor ◽  
Extracellular Nucleotide ◽  
Membrane Expression ◽  
Receptor System

The understanding of the nucleotide/P2 receptor system in the regulation of renal hemodynamics and transport function has grown exponentially over the last 20 yr. This review attempts to integrate the available data while also identifying areas of missing information. First, the determinants of nucleotide concentrations in the interstitial and tubular fluids of the kidney are described, including mechanisms of cellular release of nucleotides and their extracellular breakdown. Then the renal cell membrane expression of P2X and P2Y receptors is discussed in the context of their effects on renal vascular and tubular functions. Attention is paid to effects on the cortical vasculature and intraglomerular structures, autoregulation of renal blood flow, tubuloglomerular feedback, and the control of medullary blood flow. The role of the nucleotide/P2 receptor system in the autocrine/paracrine regulation of sodium and fluid transport in the tubular and collecting duct system is outlined together with its role in integrative sodium and fluid homeostasis and blood pressure control. The final section summarizes the rapidly growing evidence indicating a prominent role of the extracellular nucleotide/P2 receptor system in the pathophysiology of the kidney and aims to identify potential therapeutic opportunities, including hypertension, lithium-induced nephropathy, polycystic kidney disease, and kidney inflammation. We are only beginning to unravel the distinct physiological and pathophysiological influences of the extracellular nucleotide/P2 receptor system and the associated therapeutic perspectives.

scholarly journals Role of Ca2+ in Mediating Plant Responses to Extracellular ATP and ADP

2018 ◽  
Vol 19 (11) ◽  
pp. 3590 ◽  
Author(s):  
Greg Clark ◽  
Stanley Roux
Keyword(s):  
Cytosolic Calcium ◽  
Defense Responses ◽  
Receptor Activation ◽  
Extracellular Atp ◽  
Extracellular Nucleotides ◽  
Nucleoside Triphosphate ◽  
Plant Responses ◽  
Downstream Signaling ◽  
Nucleoside Triphosphate Diphosphohydrolase

Among the most recently discovered chemical regulators of plant growth and development are extracellular nucleotides, especially extracellular ATP (eATP) and extracellular ADP (eADP). Plant cells release ATP into their extracellular matrix under a variety of different circumstances, and this eATP can then function as an agonist that binds to a specific receptor and induces signaling changes, the earliest of which is an increase in the concentration of cytosolic calcium ([Ca2+]cyt). This initial change is then amplified into downstream-signaling changes that include increased levels of reactive oxygen species and nitric oxide, which ultimately lead to major changes in the growth rate, defense responses, and leaf stomatal apertures of plants. This review presents and discusses the evidence that links receptor activation to increased [Ca2+]cyt and, ultimately, to growth and diverse adaptive changes in plant development. It also discusses the evidence that increased [Ca2+]cyt also enhances the activity of apyrase (nucleoside triphosphate diphosphohydrolase) enzymes that function in multiple subcellular locales to hydrolyze ATP and ADP, and thus limit or terminate the effects of these potent regulators.

Amiloride-sensitive Na+channels in pelvic uroepithelium involved in renal sensory receptor activation

1998 ◽  
Vol 275 (6) ◽  
pp. R1780-R1792 ◽  
Author(s):  
Ulla C. Kopp ◽  
Kazumichi Matsushita ◽  
Rita D. Sigmund ◽  
Lori A. Smith ◽  
Shigeru Watanabe ◽  
...  
Keyword(s):  
Messenger Rna ◽  
Collecting Duct ◽  
Receptor Activation ◽  
Sensory Receptor ◽  
Renal Nerve ◽  
Pelvic Wall ◽  
Renal Nerve Activity ◽  
Collecting Duct Cells ◽  
Pelvic Perfusion ◽  
Pelvic Pressure

Stretching the renal pelvic wall increases ipsilateral afferent renal nerve activity (ARNA). This response is enhanced by inhibiting Na+-K+-ATPase with ouabain, suggesting a modulatory role for intracellular Na+ in the activation of mechanosensitive neurons. The messenger RNA for α-, β-, and γ-subunits of epithelial Na+channels (ENaC) is found in collecting duct cells. Because ENaC subunits show homology with genes involved in mechanosensation, we examined whether ENaC mRNA could be found in the pelvic wall and whether the ARNA response to increased renal pelvic pressure was modulated by blockers of the Na+channel. α-, β-, and γ-subunits are present in the pelvis. The messenger RNA for the β- and γ-subunits is readily detected by in situ hybridization throughout the uroepithelium. The ARNA response to increased renal pelvic pressure was reduced by 53 ± 10% and 40 ± 10% ( P < 0.01) by renal pelvic perfusion with the inhibitors amiloride and benzamil, respectively. Amiloride inhibited the ouabain-induced enhancement of the ARNA response to increased renal pelvic pressure. The magnitude of this inhibition was inversely correlated with the magnitude of the amiloride-mediated blockade of the ARNA response to increased renal pelvic pressure ( P < 0.001). Amiloride also reduced the ARNA response to renal pelvic administration of substance P, a mediator of the ARNA response to increased renal pelvic pressure. We conclude that the ENaC complex in the pelvic uroepithelium participates in the activation of renal pelvic mechanosensitive neurons.

A Pyruvate-Buffered Dialysis Fluid Induces Less Peritoneal Angiogenesis and Fibrosis than a Conventional Solution

2008 ◽  
Vol 28 (5) ◽  
pp. 487-496 ◽  
Author(s):  
Roos van Westrhenen ◽  
Machteld M. Zweers ◽  
Cindy Kunne ◽  
Dirk R. de Waart ◽  
Allard C. van der Wal ◽  
...  
Keyword(s):  
Blood Vessels ◽  
Degradation Products ◽  
Smooth Muscle Actin ◽  
Total Surface Area ◽  
Exposure Model ◽  
Peritoneal Membrane ◽  
Negative Effects ◽  
Alpha Smooth Muscle Actin ◽  
Peritoneal Tissue ◽  
Conventional Solution

Background Conventional lactate-buffered peritoneal dialysis (PD) fluids containing glucose and glucose degradation products are believed to contribute to the development of fibrosis and angiogenesis in the dialyzed peritoneum. To reduce potential negative effects of lactate, pyruvate was substituted as a buffer and its effects on peritoneal pathological alterations were studied in a chronic peritoneal exposure model in the rat. Methods 20 Wistar rats were infused intraperitoneally with pyruvate-buffered ( n = 9) or lactate-buffered PD fluid. After 20 weeks of daily infusion, peritoneal function was assessed. In omental peritoneal tissue, the number of blood vessels was analyzed following alpha-smooth muscle actin staining. The degree of fibrosis was quantitated in Picro Sirius Red-stained sections and by assessment of the hydroxyproline content. Plasma lactate/pyruvate and beta-hydroxybutyrate/acetoacetate (BBA/AA) ratios were determined. Plasma and dialysate vascular endothelial growth factor (VEGF) levels were quantitated by ELISA. Results The mass transfer area coefficient of creatinine was higher and the dialysate-to-plasma ratio of sodium was lower in pyruvate-treated animals compared to the lactatetreated group (0.11 vs 0.05 mL/min, p < 0.05, and 78% vs 89%, p < 0.05). The BBA/AA ratio tended to be lower in the pyruvate animals ( p = 0.07). The number of blood vessels was lower in pyruvate-treated animals (16 vs 37 per field, p < 0.001). Total surface area, luminal area, and wall/total area of the vessels were larger in the pyruvate group. The degree of fibrosis was lower in intersegmental and perivascular areas of pyruvate-exposed animals. Effluent VEGF was higher in the pyruvate group. Conclusions Replacement of lactate by pyruvate resulted in changes in peritoneal solute transport, accompanied by a reduction in both peritoneal membrane angiogenesis and fibrosis, suggesting potentially novel mechanisms to reduce glucose-driven alterations to the peritoneal membrane in PD patients.

Nucleotides regulate NaCl transport in mIMCD-K2 cells via P2X and P2Y purinergic receptors

1999 ◽  
Vol 277 (4) ◽  
pp. F552-F559 ◽  
Author(s):  
David E. McCoy ◽  
Amanda L. Taylor ◽  
Brian A. Kudlow ◽  
Katherine Karlson ◽  
Margaret J. Slattery ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Apical Membrane ◽  
Collecting Duct ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Extracellular Nucleotides ◽  
P2x Receptor ◽  
Apical Plasma Membrane ◽  
Receptor Subtypes ◽  
Nacl Transport

Extracellular nucleotides regulate NaCl transport in some epithelia. However, the effects of nucleotide agonists on NaCl transport in the renal inner medullary collecting duct (IMCD) are not known. The objective of this study was to determine whether ATP and related nucleotides regulate NaCl transport across mouse IMCD cell line (mIMCD-K2) epithelial monolayers and, if so, via what purinergic receptor subtypes. ATP and UTP inhibited Na+ absorption [measured via Na+ short-circuit current[Formula: see text])] and stimulated Cl− secretion [measured via Cl−short-circuit current ([Formula: see text])]. Using selective P2 agonists, we report that P2X and P2Y purinoceptors regulate [Formula: see text] and[Formula: see text]. By RT-PCR, two P2X receptor channels (P2X3, P2X4) and two P2Y G protein-coupled receptors (P2Y1, P2Y2) were identified. Functional localization of P2 purinoceptors suggest that [Formula: see text] is stimulated by apical membrane-resident P2Y purinoceptors and P2X receptor channels, whereas[Formula: see text] is inhibited by apical membrane-resident P2Y purinoceptors and P2X receptor channels. Together, we conclude that nucleotide agonists inhibit[Formula: see text] across mIMCD-K2 monolayers through interactions with P2X and P2Y purinoceptors expressed on the apical plasma membrane, whereas extracellular nucleotides stimulate [Formula: see text]through interactions with P2X and P2Y purinoceptors expressed on the apical plasma membrane.

Ectonucleotidases in the digestive system: focus on NTPDase3 localization

2011 ◽  
Vol 300 (4) ◽  
pp. G608-G620 ◽  
Author(s):  
Elise G. Lavoie ◽  
Brian D. Gulbransen ◽  
Mireia Martín-Satué ◽  
Elisabet Aliagas ◽  
Keith A. Sharkey ◽  
...  
Keyword(s):  
Salivary Glands ◽  
Digestive System ◽  
Biologically Active ◽  
Extracellular Nucleotides ◽  
Nucleoside Triphosphate ◽  
Intestinal Epithelial ◽  
Functional Roles ◽  
Salivary Gland Cells ◽  
P1 Receptor ◽  
Specific Localization

Extracellular nucleotides and adenosine are biologically active molecules that bind members of the P2 and P1 receptor families, respectively. In the digestive system, these receptors modulate various functions, including salivary, gastric, and intestinal epithelial secretion and enteric neurotransmission. The availability of P1 and P2 ligands is modulated by ectonucleotidases, enzymes that hydrolyze extracellular nucleotides into nucleosides. Nucleoside triphosphate diphosphohydrolases (NTPDases) and ecto-5′-nucleotidase are the dominant ectonucleotidases at physiological pH. While there is some information about the localization of ecto-5′-nucleotidase and NTPDase1 and -2, the distribution of NTPDase3 in the digestive system is unknown. We examined the localization of these ectonucleotidases, with a focus on NTPDase3, in the gastrointestinal tract and salivary glands. NTPDase1, -2, and -3 are responsible for ecto-ATPase activity in these tissues. Semiquantitative RT-PCR, immunohistochemistry, and in situ enzyme activity revealed the presence of NTPDase3 in some epithelial cells in serous acini of salivary glands and mucous acini and duct cells of sublingual salivary glands, in cells from the stratified esophageal and forestomach epithelia, and in some enteroendocrine cells of the gastric antrum. Interestingly, NTPDase2 and ecto-5′-nucleotidase are coexpressed with NTPDase3 in salivary gland cells and stratified epithelia. In the colon, neurons express NTPDase3 and glial cells express NTPDase2. Ca2+ imaging experiments demonstrate that NTPDases regulate P2 receptor ligand availability in the enteric nervous system. In summary, the specific localization of NTPDase3 in the digestive system suggests functional roles of the enzyme, in association with NTPDase2 and ecto-5′-nucleotidase, in epithelial functions such as secretion and in enteric neurotransmission.

scholarly journals Axial compartmentation of descending and ascending thin limbs of Henle's loops

2013 ◽  
Vol 304 (3) ◽  
pp. F308-F316 ◽  
Author(s):  
Kristen Y. Westrick ◽  
Bradley Serack ◽  
William H. Dantzler ◽  
Thomas L. Pannabecker
Keyword(s):  
Blood Vessels ◽  
Water Permeability ◽  
Collecting Duct ◽  
Osmotic Gradient ◽  
Loop Length ◽  
Vasa Recta ◽  
Pass Through ◽  
Solute Gradient ◽  
Radial Organization

In the inner medulla, radial organization of nephrons and blood vessels around collecting duct (CD) clusters leads to two lateral interstitial regions and preferential intersegmental fluid and solute flows. As the descending (DTLs) and ascending thin limbs (ATLs) pass through these regions, their transepithelial fluid and solute flows are influenced by variable transepithelial solute gradients and structure-to-structure interactions. The goal of this study was to quantify structure-to-structure interactions, so as to better understand compartmentation and flows of transepithelial water, NaCl, and urea and generation of the axial osmotic gradient. To accomplish this, we determined lateral distances of AQP1-positive and AQP1-negative DTLs and ATLs from their nearest CDs, so as to gauge interactions with intercluster and intracluster lateral regions and interactions with interstitial nodal spaces (INSs). DTLs express reduced AQP1 and low transepithelial water permeability along their deepest segments. Deep AQP1-null segments, prebend segments, and ATLs lie equally near to CDs. Prebend segments and ATLs abut CDs and INSs throughout much of their descent and ascent, respectively; however, the distal 30% of ATLs of the longest loops lie distant from CDs as they approach the outer medullary boundary and have minimal interaction with INSs. These relationships occur regardless of loop length. Finally, we show that ascending vasa recta separate intercluster AQP1-positive DTLs from descending vasa recta, thereby minimizing dilution of gradients that drive solute secretion. We hypothesize that DTLs and ATLs enter and exit CD clusters in an orchestrated fashion that is important for generation of the corticopapillary solute gradient by minimizing NaCl and urea loss.

P2 receptors in the regulation of renal transport mechanisms

2008 ◽  
Vol 294 (1) ◽  
pp. F10-F27 ◽  
Author(s):  
Volker Vallon
Keyword(s):  
Collecting Duct ◽  
P2 Receptors ◽  
Extracellular Nucleotides ◽  
Receptor Subtype ◽  
Receptor Subtypes ◽  
Inhibitory Influence ◽  
P2 Receptor ◽  
Transport Mechanisms ◽  
Renal Epithelia ◽  
Regulation Of Transport

Extracellular nucleotides (e.g., ATP) regulate physiological and pathophysiological processes through activation of nucleotide P2 receptors in the plasma membrane. Examples include such diverse processes as communication from taste buds to gustatory nerves, platelet aggregation, nociception, or neutrophil chemotaxis. Over approximately the last 15 years, evidence has also accumulated that cells in renal epithelia release nucleotides in response to physiological stimuli and that these nucleotides act in a paracrine and autocrine way to activate P2 receptors and play a significant role in the regulation of transport mechanisms and cell volume regulation. This review discusses potential stimuli and mechanisms involved in nucleotide release in renal epithelia and summarizes the available data on the expression and function of nucleotide P2 receptors along the native mammalian tubular and collecting duct system. Using established agonist profiles for P2 receptor subtypes, significant insights have been gained particularly into a potential role for P2Y2-like receptors in the regulation of transport mechanisms in the collecting duct. Due to the lack of receptor subtype-specific antagonists, however, the in vivo relevance of P2 receptor subtypes is unclear. Studies in gene knockout mice provided first insights including an antihypertensive activity of P2Y2receptors that is linked to an inhibitory influence on renal Na+and water reabsorption. We are only beginning to unravel the important roles of extracellular nucleotides and P2 receptors in the regulation of the diverse transport mechanisms of the kidney.

scholarly journals ATP acting through P2Y receptors causes activation of podocyte TRPC6 channels: role of podocin and reactive oxygen species

2014 ◽  
Vol 306 (9) ◽  
pp. F1088-F1097 ◽  
Author(s):  
Hila Roshanravan ◽  
Stuart E. Dryer
Keyword(s):  
Reactive Oxygen Species ◽  
Ex Vivo ◽  
Reactive Oxygen ◽  
P2y Receptors ◽  
Extracellular Nucleotides ◽  
Tubuloglomerular Feedback ◽  
Scaffolding Protein ◽  
Oxygen Species ◽  
Protein Signaling ◽  
Foot Process

Extracellular ATP may contribute to Ca2+ signaling in podocytes during tubuloglomerular feedback (TGF) and possibly as a result of local tissue damage. TRPC6 channels are Ca2+-permeable cationic channels that have been implicated in the pathophysiology of podocyte diseases. Here we show using whole cell recordings that ATP evokes robust activation of TRPC6 channels in mouse podocyte cell lines and in rat podocytes attached to glomerular capillaries in ex vivo glomerular explants. The EC50 for ATP is ∼10 μM and is maximal at 100 μM, and currents were blocked by the P2 antagonist suramin. In terms of maximal currents that can be evoked, ATP is the strongest activator of podocyte TRPC6 that we have characterized to date. Smaller currents were observed in response to ADP, UTP, and UDP. ATP-evoked currents in podocytes were abolished by TRPC6 knockdown and by pretreatment with 10 μM SKF-96365 or 50 μM La3+. ATP effects were also abolished by inhibiting G protein signaling and by the PLC/PLA2 inhibitor D-609. ATP effects on TRPC6 were also suppressed by knockdown of the slit diaphragm scaffolding protein podocin, and also by tempol, a membrane-permeable quencher of reactive oxygen species. Modulation of podocyte TRPC6 channels, especially in foot processes, could provide a mechanism for regulation of glomerular function by extracellular nucleotides, possibly leading to changes in permeation through slit diaphragms. These results raise the possibility that sustained ATP signaling could contribute to foot process effacement, Ca2+-dependent changes in gene expression, and/or detachment of podocytes.

Immunolocalization of ectonucleotidases along the rat nephron

2006 ◽  
Vol 290 (2) ◽  
pp. F550-F560 ◽  
Author(s):  
Renu M. Vekaria ◽  
David G. Shirley ◽  
Jean Sévigny ◽  
Robert J. Unwin
Keyword(s):  
Collecting Duct ◽  
Distal Tubule ◽  
Extracellular Nucleotides ◽  
Thick Ascending Limb ◽  
Sprague Dawley ◽  
Low Level ◽  
Amplification Method ◽  
Sprague Dawley Rats ◽  
Collecting Ducts ◽  
Calbindin D

Evidence is accumulating that extracellular nucleotides act as autocrine/paracrine agents in most tissues, including the kidneys. Several families of surface-located enzymes, collectively known as ectonucleotidases, can degrade nucleotides. Using immunohistochemistry, we have examined the segmental distribution of five ectonucleotidases along the rat nephron. Perfusion-fixed kidneys were obtained from anesthetized male Sprague-Dawley rats. Cryostat sections of cortical and medullary regions were incubated with antibodies specific to the following enzymes: ectonucleoside triphosphate diphosphohydrolase (NTPDase) 1, NTPDase2, NTPDase3, ectonucleotide pyrophosphatase phosphodiesterase 3 (NPP3), and ecto-5′-nucleotidase. Sections were then costained with Phaseolus vulgaris erythroagglutinin (for identification of proximal tubules) and antibodies against Tamm-Horsfall protein (for identification of thick ascending limb), calbindin-D28k (for identification of distal tubule), and aquaporin-2 (for identification of collecting duct). The tyramide signal amplification method was used when the ectonucleotidase and marker antibody were raised in the same species. The glomerulus expressed NTPDase1 and NPP3. The proximal tubule showed prominent expression of NPP3 and ecto-5′-nucleotidase in most, but not all, segments. NTPDase2 and NTPDase3, but not NPP3 or ecto-5′-nucleotidase, were expressed in the thick ascending limb and distal tubule. NTPDase3, with some low-level expression of ecto-5′-nucleotidase, was also found in cortical and outer medullary collecting ducts. Inner medullary collecting ducts displayed low-level staining for NTPDase1, NTPDase2, NTPDase3, and ecto-5′-nucleotidase. We conclude that these ectonucleotidases are differentially expressed along the nephron and may play a key role in activation of purinoceptors by nucleotides and nucleosides.

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