1
|
Savinainen A, Prusakiewicz JJ, Oswald J, Spencer E, Lou Z, Cohen ML, Rashidzadeh H, Josiah S. Pharmacokinetics and intraocular pressure-lowering activity of TAK-639, a novel C-type natriuretic peptide analog, in rabbit, dog, and monkey. Exp Eye Res 2019; 189:107836. [PMID: 31626797 DOI: 10.1016/j.exer.2019.107836] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 10/02/2019] [Accepted: 10/10/2019] [Indexed: 11/27/2022]
Abstract
TAK-639 is a topical, 9-amino acid, synthetic, C-type natriuretic peptide analog in development for the treatment of primary open-angle glaucoma and ocular hypertension. This study investigated the impact of TAK-639 on intraocular pressure (IOP), the levels of TAK-639 in aqueous humor, and the pharmacokinetic/pharmacodynamic relationship of TAK-639 following topical ocular administration to normotensive female Dutch belted rabbits, beagle dogs, and cynomolgus monkeys. In the IOP studies, rabbits (n = 6/group) and dogs (n = 8/group) received a single topical ocular dose of TAK-639 0.03%, 0.1%, 0.3%, or 0.6% in the right eye and vehicle in the left eye; monkeys (n = 8/group) received TAK-639 0.1%, 0.3%, 0.6%, 0.9%, or 1.2% in the right eye only. IOP was measured pre dose and at various time points from 0.5 to 24 h post dose for rabbits, and 1-48 h post dose for dogs and monkeys. To assess exposure in aqueous humor, another set of animals received a single ocular dose of TAK-639 0.03%, 0.1%, 0.3%, or 0.6% (rabbits, n = 20/group; dogs, n = 14/group) or TAK-639 0.3%, 0.6%, or 1.2% (monkeys, n = 10/group) in both eyes. Aqueous humor and plasma were collected at the same post dose time points at which IOP was measured. Aqueous humor and plasma TAK-639 concentrations were measured by liquid chromatography-mass spectrometry, and pharmacokinetic parameters were estimated with non-compartmental analysis. Topical ocular administration of TAK-639 resulted in a dose-dependent decrease in IOP, with maximum mean decreases in IOP ranging from -8.90% to -34.4% in the rabbit, from -16.5% to -26.4% in the dog, and from -3.43% to -13.5% in the monkey. The duration of the IOP-lowering effect was 12 h in the rabbit and monkey and 48 h in the dog. TAK-639 exposure in aqueous humor (both maximum concentration and area under the curve) was also dose dependent, with maximum concentration ranging from 0.152 to 93.6 ng/mL (0.03% and 0.6% doses, respectively) in rabbits, 0.490-13.8 ng/mL (0.03% and 0.3% doses, respectively) in dogs, and 1.16-18.1 ng/mL (0.3% and 1.2% doses, respectively) in monkeys. The pharmacokinetic/pharmacodynamic profile, when fitted to an inhibitory sigmoidal model, demonstrated that TAK-639 exposure in aqueous humor correlated well with IOP reduction in these species. The TAK-639 exposure in aqueous humor at half maximal IOP reduction (EC50) was lower in monkey and dog than in rabbit (0.2 and 0.4 vs. 2.0 ng/mL, respectively). In plasma, quantifiable concentrations of TAK-639 were low and detectable predominantly at early time points. In conclusion, in rabbit, dog, and monkey, a single topical ocular drop of TAK-639 had a significant IOP-lowering effect that correlated well with increases in TAK-639 levels in aqueous humor and resulted in minimal systemic exposure of TAK-639.
Collapse
Affiliation(s)
| | | | - Justine Oswald
- Covance Laboratories, 3301 Kinsman Boulevard, Madison, WI, 53704, USA
| | - Elizabeth Spencer
- Covance Laboratories, 3301 Kinsman Boulevard, Madison, WI, 53704, USA
| | - Zhen Lou
- Shire, a Takeda Company, 300 Shire Way, Lexington, MA, 02421, USA
| | | | | | - Serene Josiah
- Shire, a Takeda Company, 300 Shire Way, Lexington, MA, 02421, USA.
| |
Collapse
|
2
|
Kuzminov B, Turkina V, Кuzminov Y. Rationale for naphazoline effects in-depth study. CURRENT ISSUES IN PHARMACY AND MEDICAL SCIENCES 2018. [DOI: 10.1515/cipms-2018-0007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
This article presents a retrospective review of data on side effects of drugs containing naphazoline and data on toxicity of the agent when entered the body via different pathways. Most publications on clinical signs of possible naphazoline-associated side effects are lacking thorough analysis of possible causes. Limited data on the pharmacokinetics and pharmacodynamics of the drug led to various complications after its administration. Therefore, further studies on naphazoline content dynamics or products of its biotransformation in biological substrates and determination of half-life of the agent must be conducted. This will allow establishingsafe levels for different exposure pathways and harmful levels of the naphazoline with respect to its material accumulation. It should be noted that scientific publications contain controversial data regarding allergenic potential of the agent. Possible side effects of the drug on the reproductionand development are not revealed. Determination of effects the products containing naphazoline may have on immune and reproductive system is an important part of the research.
Collapse
Affiliation(s)
- Borys Kuzminov
- Department of hygiene and prophylactic toxicology , Danylo Halytsky Lviv National Medical University , Pekarska 69, 79010 Lviv , Ukraine
| | - Vira Turkina
- Central Research Laboratory and Laboratory of Industrial Toxicology , Danylo Halytsky Lviv National Medical University , Ukraine
| | - Yuriy Кuzminov
- Department of Pediatrics , Danylo Halytsky Lviv National Medical University , Ukraine
| |
Collapse
|
3
|
Ruiz-Ojeda FJ, Aguilera CM, Rupérez AI, Gil Á, Gomez-Llorente C. An analogue of atrial natriuretic peptide (C-ANP4-23) modulates glucose metabolism in human differentiated adipocytes. Mol Cell Endocrinol 2016; 431:101-8. [PMID: 27181211 DOI: 10.1016/j.mce.2016.05.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 04/27/2016] [Accepted: 05/10/2016] [Indexed: 12/21/2022]
Abstract
The present study was undertaken to investigate the effects of C-atrial natriuretic peptide (C-ANP4-23) in human adipose-derived stem cells differentiated into adipocytes over 10 days (1 μM for 4 h). The intracellular cAMP, cGMP and protein kinase A levels were determined by ELISA and gene and protein expression were determined by qRT-PCR and Western blot, respectively, in the presence or absence of C-ANP4-23. The levels of lipolysis and glucose uptake were also determined. C-ANP4-23 treatment significantly increased the intracellular cAMP levels and the gene expression of glucose transporter type 4 (GLUT4) and protein kinase, AMP-activated, alpha 1 catalytic subunit (AMPK). Western blot showed a significant increase in GLUT4 and phosphor-AMPKα levels. Importantly, the adenylate cyclase inhibitor SQ22536 abolished these effects. Additionally, C-ANP4-23 increased glucose uptake by 2-fold. Our results show that C-ANP4-23 enhances glucose metabolism and might contribute to the development of new peptide-based therapies for metabolic diseases.
Collapse
Affiliation(s)
- Francisco Javier Ruiz-Ojeda
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, Campus de Cartuja s/n, 18071 Granada, Spain; Institute of Nutrition and Food Technology "José Mataix", Center of Biomedical Research, University of Granada, Avda. del Conocimiento s/n, 18016 Armilla, Granada, Spain; Instituto de Investigación Biosanitaria ibs, Granada, Spain
| | - Concepción María Aguilera
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, Campus de Cartuja s/n, 18071 Granada, Spain; Institute of Nutrition and Food Technology "José Mataix", Center of Biomedical Research, University of Granada, Avda. del Conocimiento s/n, 18016 Armilla, Granada, Spain; Instituto de Investigación Biosanitaria ibs, Granada, Spain; CIBER Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Madrid, Spain
| | - Azahara Iris Rupérez
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, Campus de Cartuja s/n, 18071 Granada, Spain; Institute of Nutrition and Food Technology "José Mataix", Center of Biomedical Research, University of Granada, Avda. del Conocimiento s/n, 18016 Armilla, Granada, Spain
| | - Ángel Gil
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, Campus de Cartuja s/n, 18071 Granada, Spain; Institute of Nutrition and Food Technology "José Mataix", Center of Biomedical Research, University of Granada, Avda. del Conocimiento s/n, 18016 Armilla, Granada, Spain; Instituto de Investigación Biosanitaria ibs, Granada, Spain; CIBER Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Madrid, Spain
| | - Carolina Gomez-Llorente
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, Campus de Cartuja s/n, 18071 Granada, Spain; Institute of Nutrition and Food Technology "José Mataix", Center of Biomedical Research, University of Granada, Avda. del Conocimiento s/n, 18016 Armilla, Granada, Spain; Instituto de Investigación Biosanitaria ibs, Granada, Spain; CIBER Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Madrid, Spain.
| |
Collapse
|
4
|
Abstract
Motile cilia of the lungs respond to environmental challenges by increasing their ciliary beat frequency in order to enhance mucociliary clearance as a fundamental tenant of innate defense. One important second messenger in transducing the regulable nature of motile cilia is cyclic guanosine 3′,5′-monophosphate (cGMP). In this review, the history of cGMP action is presented and a survey of the existing data addressing cGMP action in ciliary motility is presented. Nitric oxide (NO)-mediated regulation of cGMP in ciliated cells is presented in the context of alcohol-induced cilia function and dysfunction.
Collapse
Affiliation(s)
- Todd A Wyatt
- VA Nebraska-Western Iowa Health Care System, Research Service, Department of Veterans Affairs Medical Center, 4101 Woolworth Avenue, Omaha, NE 68105, USA.
- Department of Environmental, Agricultural, and Occupational Health, College of Public Health, University of Nebraska Medical Center, Omaha, NE 68198-5910, USA.
- Pulmonary, Critical Care, Sleep & Allergy Division, Department of Internal Medicine, 985910 Nebraska Medical Center, Omaha, NE 68198-5910, USA .
| |
Collapse
|
5
|
Azevedo-Pinto S, Pereira-Silva P, Rocha-Sousa A. Ghrelin in ocular pathophysiology: from the anterior to the posterior segment. Peptides 2013; 47:12-9. [PMID: 23816797 DOI: 10.1016/j.peptides.2013.06.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Revised: 06/20/2013] [Accepted: 06/20/2013] [Indexed: 12/15/2022]
Abstract
Ghrelin is a 28 amino acid acylated peptide produced in several organs that binds the growth hormone secretagogues receptor type 1a (GHSR-1a). It acts over a wide range of systems, e.g. the endocrine, cardiovascular, musculoskeletal and immune systems and the eye. The aim of this work is to review the physiologic and pathologic implications of the ghrelin-GHSR-1a in the eye. A systematic revision of studies published between 2000 and 2013 in English, Spanish or Portuguese in MEDLINE, EMBASE and Scopus was performed. Search words used included: ghrelin, GHSR-1a, ocular production, iris muscular kinetics, ciliary body, glaucoma, retinopathy and uvea. The production of ghrelin by the ocular tissue has been detected both in the anterior and posterior segments, as well as the presence of GHSR-1a. This peptide promotes the relaxation of the iris sphincter and dilator muscles, being this effect independent from GHSR-1a and dependent on prostaglandins release in the first case and dependent on GHSR-1a in the second. Regarding ocular pathology, ghrelin levels in the aqueous humor appear to be decreased in individuals with glaucoma. Moreover, ghrelin has been shown to decrease the intraocular pressure in animal models of ocular hypertension through GHSR-1a. In the posterior segment, the ghrelin-GHSR-1a system interferes with the development of oxygen-induced retinopathy, being protective in the vaso-obliterative phase and deleterious in the vaso-proliferative stage of the disease. Thus, the ghrelin-GHSR-1a system presents as a possible local regulatory mechanism in the eye, with pathophysiological implications, constituting a target for future clinical and therapeutic research and interventions.
Collapse
Affiliation(s)
- Sara Azevedo-Pinto
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine, University of Porto, Portugal
| | | | | |
Collapse
|
6
|
Stefanova VT, Grifo JA, Hansis C. Derivation of novel genetically diverse human embryonic stem cell lines. Stem Cells Dev 2012; 21:1559-70. [PMID: 22204497 DOI: 10.1089/scd.2011.0642] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Human embryonic stem cells (hESCs) have the potential to revolutionize many biomedical fields ranging from basic research to disease modeling, regenerative medicine, drug discovery, and toxicity testing. A multitude of hESC lines have been derived worldwide since the first 5 lines by Thomson et al. 13 years ago, but many of these are poorly characterized, unavailable, or do not represent desired traits, thus making them unsuitable for application purposes. In order to provide the scientific community with better options, we have derived 12 new hESC lines at New York University from discarded genetically normal and abnormal embryos using the latest techniques. We examined the genetic status of the NYUES lines in detail as well as their molecular and cellular features and DNA fingerprinting profile. Furthermore, we differentiated our hESCs into the tissues most affected by a specific condition or into clinically desired cell types. To our knowledge, a number of characteristics of our hESCs have not been previously reported, for example, mutation for alpha thalassemia X-linked mental retardation syndrome, linkage to conditions with a genetic component such as asthma or poor sperm morphology, and novel combinations of ethnic backgrounds. Importantly, all of our undifferentiated euploid female lines tested to date did not show X chromosome inactivation, believed to result in superior potency. We continue to derive new hESC lines and add them to the NIH registry and other registries. This should facilitate the use of our hESCs and lead to advancements for patient-benefitting applications.
Collapse
Affiliation(s)
- Valentina T Stefanova
- Department of Obstetrics and Gynecology, New York University School of Medicine, New York, New York, USA
| | | | | |
Collapse
|
7
|
Bertazolli-Filho R, Coca-Prados M, Haddad A, Laicine EM. Molecular Analysis of Neurolysin Expression in the Rat and Bovine Ciliary Body. Curr Eye Res 2009; 32:751-6. [PMID: 17882707 DOI: 10.1080/02713680701573381] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
PURPOSE This paper deals with the capability of the ciliary epithelium to express neurolysin, involved in the inactivation of numerous neuropeptides. METHODS Total RNAs from ciliary body (CB) were processed for RT-PCR, and the amplification products were sequenced. The whole-protein extracts of CBs were analyzed using the Western blot. The CBs were processed for neurolysin immunolocalization. RESULTS The RT-PCR detected the presence of neurolysin mRNA in the ciliary body. The Western blot assays demonstrated immunochemical cross-reactivity with neurolysin. The immunoreactivity to neurolysin was observed in ciliary epithelium. CONCLUSIONS These results indicate that the ciliary epithelium expresses neurolysin.
Collapse
Affiliation(s)
- Rubens Bertazolli-Filho
- Departamento de Biologia Celular e Molecular e Bioagentes Patogêcos, Faculdade de Medicina de Ribeirão Preto/USP, 14049-900 Ribeirão Preto, SP, Brazil.
| | | | | | | |
Collapse
|
8
|
Voltage-gated potassium channel Kv1.3 in rabbit ciliary epithelium regulates the membrane potential via coupling intracellular calcium. Chin Med J (Engl) 2008. [DOI: 10.1097/00029330-200811020-00012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
|
9
|
Rocha-Sousa A, Saraiva J, Henriques-Coelho T, Falcão-Reis F, Correia-Pinto J, Leite-Moreira AF. Ghrelin as a novel locally produced relaxing peptide of the iris sphincter and dilator muscles. Exp Eye Res 2006; 83:1179-87. [PMID: 16904667 DOI: 10.1016/j.exer.2006.06.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2006] [Revised: 05/16/2006] [Accepted: 06/10/2006] [Indexed: 11/19/2022]
Abstract
Ghrelin is a recently described acylated peptide, which works as a somatosecretagogue and has described effects on the smooth, skeletal and cardiac muscle. We examined the production and effects of ghrelin on relaxation of the iris muscles. Contractile effects of 1-5 human ghrelin (frGhr, 10(-9)-6 x 10(-5)M) and 1-5 human des-octanoyl-ghrelin (d-frGhr; 10(-9)-6 x 10(-5)M) were tested on iris rabbit sphincter (n=11 frGhr; n=7 d-frGhr), dilator (n=6 frGhr; n=6 d-frGhr) and rat sphincter (n=6 frGhr; n=8 d-frGhr) precontracted muscles. On rabbit sphincter the effect of frGhr was also tested in presence of: i) L-NA (10(-5)M; n=7); ii) indomethacin (10(-5)M; n=7); iii) DLys(3)GHRP6 (10(-4)M; n=6); and iv) apamin+carybdotoxin (10(-6)M; n=6). Furthermore, on rabbit dilator the effect of frGhr was tested in presence of DLys(3)GHRP6 (10(-4)M; n=7). Finally, ghrelin mRNA production was assessed by "in situ" hybridization in Wistar rat eyes (n=8). In all muscles, frGhr promoted a concentration-dependent relaxation, maximal at 6 x 10(-5)M, 1.5-3 min after its addition, decreasing tension by 34.1+/-12.1%, 25.8+/-4.8% and 52.1+/-10.3% in the rabbit sphincter, dilator and rat sphincter, respectively. In the rabbit sphincter the relaxing effects of frGhr were: (i) enhanced in presence of DLys(3)GHRP6 (118.1+/-21.1%); (ii) blunted by indomethacin; and (iii) not altered by apamin+carybdotoxin (36.4+/-14.4%) or L-NA (52.4+/-11.4%). Relaxing effects of d-frGhr in rabbit (43.3+/-5.2%) and rat (77.1+/-15.3%) sphincter muscles were similar to those of frGhr. In rabbit dilator muscle, d-frGhr did not significantly alter active tension and the relaxing effect of frGhr was blunted by GHSR-1a blockage. Ghrelin mRNA was identified in iris posterior epithelium. In conclusion, ghrelin is a novel, locally produced, relaxing agent of iris dilator and sphincter muscles, an effect that is mediated by GHSR-1a in the former, but not in the latter. Furthermore, in the sphincter it seems to be mediated by prostaglandins, but not by NO or K(Ca) channels.
Collapse
Affiliation(s)
- A Rocha-Sousa
- Laboratory of Physiology, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal.
| | | | | | | | | | | |
Collapse
|
10
|
Ghosh S, Choritz L, Geibel J, Coca-Prados M. Somatostatin modulates PI3K-Akt, eNOS and NHE activity in the ciliary epithelium. Mol Cell Endocrinol 2006; 253:63-75. [PMID: 16764985 DOI: 10.1016/j.mce.2006.05.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2006] [Revised: 04/10/2006] [Accepted: 05/02/2006] [Indexed: 12/20/2022]
Abstract
Somatostatin (SST) is a biologically active peptide produced in neuroendocrine cells. In the present study, we provide evidence of pro-SST and SST receptor (SSTR1 and 2A) mRNA expression in ocular ciliary epithelium (CE). SST or SST-like immunoreactivity was detected by radioimmunoassay in tissue extract from ciliary processes and in aqueous humor. The distinct immunolabeling of CE with SST and proprotein convertases PC1 and PC2 antibodies suggested a tissue and cell-specific processing of pro-SST. SST (10(-8) to 10(-4)M) added exogenously to the CE, elicited the following effects: (i) a dose-dependent attenuation of Na+/H+-exchanger (NHE) activity; (ii) up to a two-fold increase phosphorylation of p-Akt-Ser473 and of p-eNOS-Ser617, and (iii) lack of response on intracellular cyclic GMP production. LY294002, a PI3K-inhibitor, blocked SST-induced p-Akt-Ser473 and partially p-eNOS-Ser617, however, it did not reverse SST-induced NHE attenuation. Collectively, these results suggested involvement of SST in multiple intracellular signaling pathways in the CE.
Collapse
Affiliation(s)
- Sikha Ghosh
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, CT 06510, USA
| | | | | | | |
Collapse
|
11
|
Singh G, Kuc RE, Maguire JJ, Fidock M, Davenport AP. Novel snake venom ligand dendroaspis natriuretic peptide is selective for natriuretic peptide receptor-A in human heart: downregulation of natriuretic peptide receptor-A in heart failure. Circ Res 2006; 99:183-90. [PMID: 16778132 DOI: 10.1161/01.res.0000232322.06633.d3] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The natriuretic peptides are considered to be cardioprotective; however, their receptors have not been identified in human myocardium using radiolabeled analogs. Dendroaspis natriuretic peptide (DNP) has been recently identified as a new member of this peptide family and is thought to be less susceptible to enzymatic degradation. Therefore, we have developed the novel radiolabeled analog [125I]-DNP and used this to localize high-affinity (K(D)=0.2 nmol/L), saturable, specific binding sites in adult human heart (n=6) and coronary artery (n=8). In competition binding experiments, atrial natriuretic peptide and brain type natriuretic peptide had greater affinity for [125I]-DNP binding sites than C-type natriuretic peptide and the natriuretic peptide receptor (NPR)-C ligand, cANF. This rank order of potency suggested binding of [125I]-DNP was specific to NPR-A. Messenger RNA encoding NPR-A was identified in left ventricle and coronary artery smooth muscle, and expression was confirmed by immunocytochemical studies at the protein level. In addition, fluorescence dual labeling immunocytochemistry localized NPR-A protein to cardiomyocytes, endocardial endothelial cells, and smooth muscle of intramyocardial vessels. Importantly, we demonstrated a significant downregulation in the density of NPR-A in heart and coronary artery of patients with ischemic heart disease that may explain, in part, the attenuated natriuretic peptide response reported in this patient group.
Collapse
Affiliation(s)
- Gurminder Singh
- Clinical Pharmacology Unit, University of Cambridge, Level 6, Centre for Clinical Investigation, Box 110, Addenbrooke's Hospital, Cambridge CB2 2QQ, UK
| | | | | | | | | |
Collapse
|
12
|
Hansis C, Barreto G, Maltry N, Niehrs C. Nuclear reprogramming of human somatic cells by xenopus egg extract requires BRG1. Curr Biol 2004; 14:1475-80. [PMID: 15324664 DOI: 10.1016/j.cub.2004.08.031] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2004] [Revised: 06/08/2004] [Accepted: 06/21/2004] [Indexed: 10/26/2022]
Abstract
Animal cloning by nuclear transplantation in amphibia was demonstrated almost half a century ago and raised the question of the mechanisms and genes involved in nuclear reprogramming. Here, we demonstrate nuclear reprogramming of permeabilized human cells using extracts from Xenopus laevis eggs and early embryos. We show upregulation of pluripotency markers Oct-4 and germ cell alkaline phosphatase (GCAP) in 293T cells and human primary leukocytes. Reprogrammed leukocytes had a limited life span and did not express surface antigens characteristic of pluripotent cells, indicating that reprogramming was incomplete. Reprogramming activity was detected in egg and early embryo extracts until early blastula stage. Late blastula-stage extracts were not only inactive but also inhibitory to reprogramming. Screening for factors required for reprogramming identified the chromatin remodeling ATPase BRG1. Antibody depletion of BRG1 protein or expression of dominant-negative BRG1 abolished the reprogramming ability of amphibian extracts. Conversely, overexpression of BRG1 in Xenopus animal caps extended their competence from blastula to gastrula stage to respond to basic fibroblast growth factor (bFGF) treatment with induction of the mesodermal marker Xbra. Dissection of the molecular machinery using a simplified assay system may aid in achieving complete nuclear reprogramming of somatic cells for regenerative medicine.
Collapse
Affiliation(s)
- Christoph Hansis
- Division of Molecular Embryology, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
| | | | | | | |
Collapse
|
13
|
Fidzinski P, Salvador-Silva M, Choritz L, Geibel J, Coca-Prados M. Inhibition of NHE-1 Na+/H+exchanger by natriuretic peptides in ocular nonpigmented ciliary epithelium. Am J Physiol Cell Physiol 2004; 287:C655-63. [PMID: 15140751 DOI: 10.1152/ajpcell.00552.2003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The natriuretic peptides (NPs) atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP) display hypotensive effects in the mammalian eye by lowering the intraocular pressure (IOP), a function that is mediated by the bilayer ocular ciliary epithelium (CE), in conjunction with the trabecular meshwork. ANP regulates Na+/H+exchanger (NHE) activity, and inhibitors of NHE have been shown to lower IOP. We examined whether NPs influence the NHE activity of the CE, which is comprised of pigmented (PE) and nonpigmented (NPE) epithelial cells, by directly recording the rate of intracellular pH (pHi) recovery from its inner NPE cell layer. NPs inhibited, in a dose-dependent manner (1–100 nM), the rate of pHirecovery with the order of potency CNP > ANP > BNP, indicative that this inhibition is mediated by the presence of NPR type B receptors. 8-Bromo-cGMP (8-BrcGMP), a nonhydrolyzable analog of cGMP, mimicked NPs in inhibiting the rate of Na+-dependent pHirecovery. In contrast, ethylisopropyl amiloride (EIPA, 100 nM) or amiloride (10 μM) completely abolished the pHirecovery by NHE. 18α-Glycyrrhetinic acid (18α-GA), a gap junction blocker, attenuated the inhibitory effect of CNP on the rate of pHirecovery, suggesting that NHE activity in both cell layers of the CE is coregulated. This interpretation was supported, in part, by the coexpression of NHE-1 isoform mRNA in both NPE and PE cells. The mechanism by which the inhibitory effect of NPs on NHE-1 activity might influence the net solute movement or fluid transport by the bilayer CE remains to be determined.
Collapse
Affiliation(s)
- Pawel Fidzinski
- Dept. of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, CT 06510, USA
| | | | | | | | | |
Collapse
|
14
|
Zhong L, Chu E, Chu J, Chu TC. CNP-induced changes in pHi, cGMP/cAMP and mRNA expression of natriuretic peptide receptors in human trabecular meshwork cells. J Ocul Pharmacol Ther 2004; 19:425-36. [PMID: 14583135 DOI: 10.1089/108076803322472999] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
It has been demonstrated that natriuretic peptides lower intraocular pressure, however, the underlying cellular mechanism(s) mediating this response remain(s) to be determined. The purpose of this study was to investigate the effects of C-type natriuretic peptide (CNP) on pH(i), cGMP/cAMP and expression of atrial natriuretic peptide receptor (NPR-A), brain natriuretic peptide receptor (NPR-B) and C-type natriuretic peptide receptor (NPR-C), in HTM cells. At concentrations of 10(-7) M, CNP caused an acidification of pH(i). In addition, CNP caused a dose-dependent increase in cGMP formation and inhibition of forskolin-stimulated cAMP accumulation. These changes were not significantly altered in the absence of 10(-3) M isobutylmethylxanthine (IBMX). Treatment with the NPR-A antagonist, anantin, produced no influence on basal cGMP/cAMP levels, the CNP-stimulated cGMP accumulation and CNP-induced inhibition of forskolin-stimulated cAMP accumulation. However, CNP-induced reduction of forskolin-stimulated cAMP accumulation was inhibited by pretreatment with pertussis toxin (PTX). Furthermore, NPRB receptors were predominantly expressed and pretreatment with CNP (10(-7) M, 24hr) enhanced all NPR mRNAs expression which was not altered by higher concentrations or longer incubation. Results demonstrate that NPR-A, NPR-B and NPR-C receptors' expression can be up-regulated by CNP treatment. CNP activates NPR-B receptors preferentially to increase cGMP accumulation and acts through the PTX-sensitive cAMP-signaling pathway leading to a decrease in pH(i).
Collapse
Affiliation(s)
- Lichun Zhong
- Morehouse School of Medicine, Atlanta, GA 30310, USA
| | | | | | | |
Collapse
|
15
|
Potter DE, Russell KRM, Manhiani M. Bremazocine increases C-type natriuretic peptide levels in aqueous humor and enhances outflow facility. J Pharmacol Exp Ther 2004; 309:548-53. [PMID: 14742737 DOI: 10.1124/jpet.103.063107] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A relatively selective agonist of kappa opioid receptors (KOR), bremazocine (BRE), lowers intraocular pressure in rabbits, in part, by increasing natriuretic peptide levels in aqueous humor and by enhancing total outflow facility (TOF). Natriuretic peptide (NP) levels [atrial NP (ANP), brain NP (BNP), and C-type NP (CNP)] were measured in aqueous humor of rabbits either by radioimmunoassay or enzyme immunoassay. TOF was determined in rabbits by two-level constant pressure perfusion of the anterior chamber. Experimental regimens included topical treatment with BRE in the presence or absence of KOR antagonist (norbinaltorphimine), protein kinase C inhibitor (chelerythrine), and natriuretic peptide receptor antagonist (isatin). The rank order of basal NP levels in aqueous humor of rabbits was BNP CNP > ANP. Topical administration of BRE (1-100 microg) caused dose-related elevations of CNP levels in aqueous humor that were inhibited by topical pretreatment with either norbinaltorphimine (100 microg, bilaterally) or chelerythrine (10 microg, bilaterally). Topically administered BRE (100 microg) also elevated levels of ANP and BNP in aqueous humor and evoked an 80% increase in TOF. The increase in TOF was antagonized by topical pretreatment with either norbinaltorphimine (100 microg, bilaterally) or isatin (100 microg, bilaterally). Bremazocine induced an increase in NP (ANP, BNP, and CNP) levels and TOF in rabbits by activating KOR. The increase in CNP levels elicited by BRE was inhibited by norbinaltorphimine and chelerythrine; therefore, this event is most likely mediated by a KOR-linked activation of protein kinase C. These data provide evidence that the increase in TOF elicited by BRE was mediated by a KOR-activated paracrine effect of NPs on tissues within ocular outflow tract(s).
Collapse
Affiliation(s)
- David E Potter
- Medical University of South Carolina, Storm Eye Institute, Department of Ophthalmology, Charleston, SC 29425, USA.
| | | | | |
Collapse
|
16
|
McLean AS, Huang SJ, Nalos M, Tang B, Stewart DE. The confounding effects of age, gender, serum creatinine, and electrolyte concentrations on plasma B-type natriuretic peptide concentrations in critically ill patients. Crit Care Med 2003; 31:2611-8. [PMID: 14605532 DOI: 10.1097/01.ccm.0000094225.18237.20] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To investigate the confounding effects of age, gender, serum creatinine, and electrolyte concentrations on plasma B-type natriuretic peptide (BNP) concentrations in critically ill patients. DESIGN A prospective cross-sectional study. SETTING A 20-bed general intensive care unit of a tertiary referral hospital. PATIENTS Patients were 121 patients admitted to the intensive care unit over a period of 9 wks. INTERVENTIONS Intravenous blood was collected for BNP measurements, and cardiac investigations including echocardiography were carried out for every patient on admission. MEASUREMENTS AND MAIN RESULTS The mean BNP concentration was 201 +/- 317 pg/mL (n = 121). Thirty-five patients (28.9%), identified to have cardiac abnormalities, exhibited higher BNP concentrations than those without cardiac abnormalities (518 +/- 394 vs. 60 +/- 98 pg/mL, p <.001). The females exhibited higher concentrations of BNP than males in the noncardiac abnormality group (96 +/- 132 pg/mL, n = 39 vs. 31 +/- 38 pg/mL, n = 47, p =.016). BNP correlated significantly with age (r2 =.19) and creatinine (r2 =.084). The latter correlation became insignificant when patients with cardiac abnormality were excluded. No correlation was found between serum Na+ and K+ concentrations with BNP. Multivariate analyses demonstrated that the presence of cardiac abnormalities accounted for nearly 50% of the BNP variation. Addition of age and gender improved R2 to 60%. The contribution of creatinine was found to be insignificant. There was no association between BNP concentrations and serum Na+ and K+ concentrations. Logistic analysis confirmed that BNP is the strongest predictor for cardiac abnormalities in the critically ill patients. CONCLUSION The current study demonstrated that plasma BNP concentrations increased with age and were higher in females than in males. Although the presence of cardiac disease was the most important determinant for BNP variations, age and gender also contributed significantly. The results suggest that age and gender need to be taken into account in the interpretation of BNP concentrations in critically ill patients.
Collapse
Affiliation(s)
- Anthony S McLean
- Department of Intensive Care Medicine, Nepean Hospital, University of Sydney, Penrith, NSW, Australia.
| | | | | | | | | |
Collapse
|
17
|
Coca-Prados M, Ghosh S, Wang Y, Escribano J, Herrala A, Vihko P. Sex steroid hormone metabolism takes place in human ocular cells. J Steroid Biochem Mol Biol 2003; 86:207-16. [PMID: 14568574 DOI: 10.1016/j.jsbmb.2003.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Steroids are potentially important mediators in the pathophysiology of ocular diseases. In this study, we report on the gene expression in the human eye of a group of enzymes, the 17beta-hydroxysteroid dehydrogenases (17HSDs), involved in the biosynthesis and inactivation of sex steroid hormones. In the eye, the ciliary epithelium, a neuroendocrine secretory epithelium, co-expresses the highest levels of 17HSD2 and 5 mRNAs, and in lesser level 17HSD7 mRNA. The regulation of gene expression of these enzymes was investigated in vitro in cell lines, ODM-C4 and chronic open glaucoma (GCE), used as cell models of the human ciliary epithelium. The estrogen, 17beta-estradiol (10(-7) M) and androgen agonist, R1881 (10(-8) M) elicited in ODM-C4 and GCE cells over a 24 h time course a robust up-regulation of 17HSD7 mRNA expression. 17HSD2 was up-regulated by estradiol in ODM-C4 cells, but not in GCE cells. Under steady-state conditions, ODM-C4 cells exhibited a predominant 17HSD2 oxidative enzymatic activity. In contrast, 17HSD2 activity was low or absent in GCE cells. Our collective data suggest that cultured human ciliary epithelial cells are able to metabolize estrogen, androgen and progesterone, and that 17HSD2 and 7 in these cells are sex steroid hormone-responsive genes and 17HSD7 is responsible to keep on intra/paracrine estrogenic milieu.
Collapse
Affiliation(s)
- Miguel Coca-Prados
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, 330 Cedar Street, New Haven, CT 06510, USA.
| | | | | | | | | | | |
Collapse
|
18
|
Morita R, Ukyo N, Furuya M, Uchiyama T, Hori T. Atrial natriuretic peptide polarizes human dendritic cells toward a Th2-promoting phenotype through its receptor guanylyl cyclase-coupled receptor A. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:5869-75. [PMID: 12794112 DOI: 10.4049/jimmunol.170.12.5869] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Atrial natriuretic peptide (ANP) is a cardiovascular hormone secreted mainly by the cardiac atria and regulates the volume-pressure homeostasis. The action of ANP is mediated by its receptor, guanylyl cyclase-coupled receptor A (GC-A). In this study, we explored the possibility that ANP and GC-A may play a role in the dendritic cell (DC)-mediated immune regulation. We first examined the expression of GC-A in human monocyte-derived DCs in comparison with monocytes and found that DCs but not monocytes express GC-A at both the mRNA and protein levels. DCs responded to ANP with an increase in intracellular cGMP in a dose-dependent manner, indicating that GC-A expressed on DCs is functional. Furthermore, treatment of DCs with ANP decreased production of IL-12 and TNF-alpha and conversely increased that of IL-10 upon stimulation with LPS. In accordance with this change of cytokine production, DCs treated with ANP plus LPS promoted differentiation of naive CD4(+) T cells into a Th2 phenotype. Finally, we presented evidence that ANP affected cytokine production of fresh whole blood stimulated with LPS in line with the above-mentioned results. These results indicate that ANP polarizes human DCs toward a Th2-promoting phenotype through GC-A and thus can regulate immune responses.
Collapse
Affiliation(s)
- Rimpei Morita
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | | | | | | | | |
Collapse
|
19
|
Dynorphin Modulates Ocular Hydrodynamics and Releases Atrial Natriuretic Peptide via Activation of κ-Opioid Receptors. Exp Eye Res 2002. [DOI: 10.1006/exer.2002.2024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
20
|
Bordenave L, Georges A, Bareille R, Conrad V, Villars F, Amédée J. Human bone marrow endothelial cells: a new identified source of B-type natriuretic peptide. Peptides 2002; 23:935-40. [PMID: 12084525 DOI: 10.1016/s0196-9781(02)00004-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
B-type natriuretic peptide (BNP) is a hormone mainly secreted by cardiac ventricle myocytes and which is increased in cardiac diseases. Moreover, BNP expression has been shown in various cell/tissue types. Six different human endothelial cell (EC) culture models arising from macro and microcirculation either primary cultures or cell lines were cultured and screened for BNP presence and secretion. All cell types expressed BNP mRNA while only the ECs arising from bone marrow stromal compartment secreted high amounts of BNP protein. This report is the first to identify ECs as a new source of BNP. However, BNP secretion is limited to a particular EC type.
Collapse
Affiliation(s)
- Laurence Bordenave
- U-443-INSERM, Université Victor Segalen Bordeaux 2, 146 rue Léo Saignat, Bordeaux, France.
| | | | | | | | | | | |
Collapse
|
21
|
Russell KR, Moore TT, Potter DE. Elevation of atrial natriuretic peptide levels in aqueous humor of the rabbit by kappa opioid receptor agonists. Neuropeptides 2001; 35:232-7. [PMID: 12030807 DOI: 10.1054/npep.2001.0883] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Following the topical administration of three kappa agonists (bremazocine, spiradoline and ICI 204448) to rabbit eyes, aqueous humor samples were analyzed for levels of atrial natriuretic peptide (ANP). Bremazocine (BRE) and spiradoline (SPR) elevated aqueous ANP levels in a dose-dependent manner. In contrast, ICI had no significant effect on ANP levels in aqueous humor. Nor-binaltorphimine (nor-BNI), a selective kappa opioid receptor antagonist, was used to assess kappa opioid receptor involvement and glibenclamide, an ATP-sensitive K+ channel blocker, was used to test for the role of ATP-sensitive potassium channels in ANP release. Pretreatment with nor-BNI antagonized the increases in ANP levels observed with both BRE and SPR. Likewise, glibenclamide suppressed the stimulation of ANP secretion by bremazocine. In summary, BRE and SPR increased ANP levels in aqueous humor of rabbits, in part, via activation of K+(ATP) channels that are assumed to be associated with kappa opioid receptors.
Collapse
Affiliation(s)
- K R Russell
- Morehouse School of Medicine, Department of Pharmacology and Toxicology, Atlanta, GA 30310-1495, USA.
| | | | | |
Collapse
|
22
|
Patil RV, Han Z, Yiming M, Yang J, Iserovich P, Wax MB, Fischbarg J. Fluid transport by human nonpigmented ciliary epithelial layers in culture: a homeostatic role for aquaporin-1. Am J Physiol Cell Physiol 2001; 281:C1139-45. [PMID: 11546649 DOI: 10.1152/ajpcell.2001.281.4.c1139] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We report for the first time that cultured nonpigmented human ciliary epithelial (NPE) cell layers transport fluid. Cells were grown to confluence on permeable membrane inserts, and fluid transport across the resulting cell layers was determined by volume clamp at 37 degrees C. These cell layers translocated fluid from the apical to the basal side at a steady rate of 3.6 microl x h(-1) x cm(-2) (n = 4) for 8 h. This fluid movement was independent of hydrostatic pressure and was completely inhibited by 1 mM ouabain, suggesting it arose from fluid transport. Mercuric chloride, a nonspecific but potent blocker of Hg(2+)-sensitive aquaporins, and aquaporin-1 antisense oligonucleotides both partially inhibited fluid transport across the cell layers, which suggests that water channels have a role in NPE cell homeostasis. In addition, these results suggest that of the two ciliary epithelial layers in tandem, the NPE layer by itself can transport fluid. This cultured layer, therefore, constitutes an interesting model that may be useful for physiological and pharmacological characterization of ciliary epithelial fluid secretion.
Collapse
Affiliation(s)
- R V Patil
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
| | | | | | | | | | | | | |
Collapse
|
23
|
Bertazolli-Filho R, Ghosh S, Huang W, Wollmann G, Coca-Prados M. Molecular evidence that human ocular ciliary epithelium expresses components involved in phototransduction. Biochem Biophys Res Commun 2001; 284:317-25. [PMID: 11394879 DOI: 10.1006/bbrc.2001.4970] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Here we report the expression, in the human ocular ciliary epithelium and in a human nonpigmented (NPE) ciliary epithelial cell line, of genes usually restricted to cone and rod photoreceptor cells of the retina. By RT-PCR and DNA sequencing we identified the expression of rhodopsin and components linked to its deactivation, including rhodopsin kinase, recoverin, and visual arrestin. We also detected the expression of transducin (T-alpha), phosphodiesterase (PDE-alpha), and cGMP-gated channel alpha-subunits. Cultured NPE cells responded to treatment with phorbol ester by enhancing the expression of rhodopsin mRNA three- to fourfold. Indirect immunofluorescence of the intact ciliary epithelium with monoclonal antibodies (MAbs) against rhodopsin, rhodopsin kinase, and visual arrestin revealed labeling preferentially restricted to the NPE cells. Furthermore, Western blot analysis of whole lysates from the pars plicata region of the human ciliary epithelium with MAbs demonstrated immunochemical cross-reactivity with proteins of molecular mass similar to rhodopsin (36 kDa), rhodopsin kinase (64 to 66 kDa), and arrestin (48-52 kDa) from the human retina. These results provide the first molecular evidence that components of a non-visual phototransduction pathway are expressed in the human ocular NPE ciliary epithelium, which may be linked to circadian entrainment tasks.
Collapse
Affiliation(s)
- R Bertazolli-Filho
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, 330 Cedar Street, New Haven, Connecticut 06510, USA
| | | | | | | | | |
Collapse
|
24
|
Sellitti DF, Perrella G, Doi SQ, Curcio F. Natriuretic peptides increase cAMP production in human thyrocytes via the natriuretic peptide clearance receptor (NPR-C). REGULATORY PEPTIDES 2001; 97:103-9. [PMID: 11164945 DOI: 10.1016/s0167-0115(00)00184-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The relationship between natriuretic peptides and adenylyl cyclase/cAMP signal transduction has generally been shown to be an inhibitory one, mediated via the NPR-C receptor coupled to adenylyl cyclase by inhibitory G proteins (Gi). In the present studies, we have investigated the modulation of cAMP by natriuretic peptides in a long-term culture of human thyroid cells. Competition of [125I] rat ANF binding to human thyrocytes (HTU-5) by rat ANF (99-126) and by the NPR-C-specific analog C-ANF (4-23) indicated that greater than 97% of the ANF binding sites on HTU-5 cells are of the NPR-C type. However, rather than inhibiting intracellular cAMP in these cells, ANF increased maximal cAMP to 200-300% of control value. The ANF-induced increase in cAMP was duplicated by C-ANF (4-23). Basal cAMP content was reduced, and the response to ANF was abolished when the cells were grown in low (0.5%) serum without the addition of pituitary and hypothalamic extracts. CNP-22 also increased cAMP above control in HTU-5 cells identically to ANF. Neither ANF nor C-ANF (4-23) had any effect on cAMP in a culture of rat aortic smooth muscle cells. These results provide the first evidence for a positive effect of natriuretic peptides on cAMP mediated through the NPR-C, suggesting the possibility of an alternative mode of signaling by this receptor subtype.
Collapse
Affiliation(s)
- D F Sellitti
- Department of Medicine, Divisions of Endocrinology and Nephrology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, A 3060, Bethesda, MD 20814-4799, USA
| | | | | | | |
Collapse
|