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Ariyeloye S, Kämmerer S, Klapproth E, Wielockx B, El-Armouche A. Intertwined regulators: hypoxia pathway proteins, microRNAs, and phosphodiesterases in the control of steroidogenesis. Pflugers Arch 2024; 476:1383-1398. [PMID: 38355819 PMCID: PMC11310285 DOI: 10.1007/s00424-024-02921-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/25/2024] [Accepted: 02/05/2024] [Indexed: 02/16/2024]
Abstract
Oxygen sensing is of paramount importance for maintaining cellular and systemic homeostasis. In response to diminished oxygen levels, the hypoxia-inducible factors (HIFs) orchestrate various biological processes. These pivotal transcription factors have been identified as key regulators of several biological events. Notably, extensive research from our group and others has demonstrated that HIF1α exerts an inverse regulatory effect on steroidogenesis, leading to the suppression of crucial steroidogenic enzyme expression and a subsequent decrease in steroid levels. These steroid hormones occupy pivotal roles in governing a myriad of physiological processes. Substantial or prolonged fluctuations in steroid levels carry detrimental consequences across multiple organ systems and underlie various pathological conditions, including metabolic and immune disorders. MicroRNAs serve as potent mediators of multifaceted gene regulatory mechanisms, acting as influential epigenetic regulators that modulate a broad spectrum of gene expressions. Concomitantly, phosphodiesterases (PDEs) play a crucial role in governing signal transduction. PDEs meticulously manage intracellular levels of both cAMP and cGMP, along with their respective signaling pathways and downstream targets. Intriguingly, an intricate interplay seems to exist between hypoxia signaling, microRNAs, and PDEs in the regulation of steroidogenesis. This review highlights recent advances in our understanding of the role of microRNAs during hypoxia-driven processes, including steroidogenesis, as well as the possibilities that exist in the application of HIF prolyl hydroxylase (PHD) inhibitors for the modulation of steroidogenesis.
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Affiliation(s)
- Stephen Ariyeloye
- Institute of Clinical Chemistry and Laboratory Medicine, Dresden, Germany
| | - Susanne Kämmerer
- Department of Pharmacology and Toxicology, Medical Faculty, Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Erik Klapproth
- Department of Pharmacology and Toxicology, Medical Faculty, Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Ben Wielockx
- Institute of Clinical Chemistry and Laboratory Medicine, Dresden, Germany.
| | - Ali El-Armouche
- Department of Pharmacology and Toxicology, Medical Faculty, Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany.
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Gambaryan S, Mohagaonkar S, Nikolaev VO. Regulation of the renin-angiotensin-aldosterone system by cyclic nucleotides and phosphodiesterases. Front Endocrinol (Lausanne) 2023; 14:1239492. [PMID: 37674612 PMCID: PMC10478253 DOI: 10.3389/fendo.2023.1239492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 08/02/2023] [Indexed: 09/08/2023] Open
Abstract
The renin-angiotensin-aldosterone system (RAAS) is one of the key players in the regulation of blood volume and blood pressure. Dysfunction of this system is connected with cardiovascular and renal diseases. Regulation of RAAS is under the control of multiple intracellular mechanisms. Cyclic nucleotides and phosphodiesterases are the major regulators of this system since they control expression and activity of renin and aldosterone. In this review, we summarize known mechanisms by which cyclic nucleotides and phosphodiesterases regulate renin gene expression, secretion of renin granules from juxtaglomerular cells and aldosterone production from zona glomerulosa cells of adrenal gland. We also discuss several open questions which deserve future attention.
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Affiliation(s)
- Stepan Gambaryan
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, Saint Petersburg, Russia
| | - Sanika Mohagaonkar
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Viacheslav O. Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
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3
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Egbert JR, Uliasz TF, Lowther KM, Kaback D, Wagner BM, Healy CL, O’Connell TD, Potter LR, Jaffe LA, Yee SP. Epitope-tagged and phosphomimetic mouse models for investigating natriuretic peptide-stimulated receptor guanylyl cyclases. Front Mol Neurosci 2022; 15:1007026. [PMID: 36340689 PMCID: PMC9627482 DOI: 10.3389/fnmol.2022.1007026] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 09/28/2022] [Indexed: 01/25/2023] Open
Abstract
The natriuretic peptide receptors NPR1 and NPR2, also known as guanylyl cyclase A and guanylyl cyclase B, have critical functions in many signaling pathways, but much remains unknown about their localization and function in vivo. To facilitate studies of these proteins, we developed genetically modified mouse lines in which endogenous NPR1 and NPR2 were tagged with the HA epitope. To investigate the role of phosphorylation in regulating NPR1 and NPR2 guanylyl cyclase activity, we developed mouse lines in which regulatory serines and threonines were substituted with glutamates, to mimic the negative charge of the phosphorylated forms (NPR1-8E and NPR2-7E). Here we describe the generation and applications of these mice. We show that the HA-NPR1 and HA-NPR2 mice can be used to characterize the relative expression levels of these proteins in different tissues. We describe studies using the NPR2-7E mice that indicate that dephosphorylation of NPR2 transduces signaling pathways in ovary and bone, and studies using the NPR1-8E mice that indicate that the phosphorylation state of NPR1 is a regulator of heart, testis, and adrenal function.
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Affiliation(s)
- Jeremy R. Egbert
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, United States,*Correspondence: Jeremy R. Egbert,
| | - Tracy F. Uliasz
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, United States
| | - Katie M. Lowther
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, United States,Center for Mouse Genome Modification, University of Connecticut Health Center, Farmington, CT, United States
| | - Deborah Kaback
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, United States,Center for Mouse Genome Modification, University of Connecticut Health Center, Farmington, CT, United States
| | - Brandon M. Wagner
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, United States
| | - Chastity L. Healy
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, United States
| | - Timothy D. O’Connell
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, United States
| | - Lincoln R. Potter
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, United States,Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, United States,Lincoln R. Potter,
| | - Laurinda A. Jaffe
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, United States,Laurinda A. Jaffe,
| | - Siu-Pok Yee
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, United States,Center for Mouse Genome Modification, University of Connecticut Health Center, Farmington, CT, United States,Siu-Pok Yee,
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Chen Y, Iyer SR, Nikolaev VO, Naro F, Pellegrini M, Cardarelli S, Ma X, Lee HC, Burnett JC. MANP Activation Of The cGMP Inhibits Aldosterone Via PDE2 And CYP11B2 In H295R Cells And In Mice. Hypertension 2022; 79:1702-1712. [PMID: 35674049 PMCID: PMC9309987 DOI: 10.1161/hypertensionaha.121.18906] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Aldosterone is a critical pathological driver for cardiac and renal diseases. We recently discovered that mutant atrial natriuretic peptide (MANP), a novel atrial natriuretic peptide (ANP) analog, possessed more potent aldosterone inhibitory action than ANP in vivo. MANP and natriuretic peptide (NP)-augmenting therapy sacubitril/valsartan are under investigations for human hypertension treatment. Understanding the elusive mechanism of aldosterone inhibition by NPs remains to be a priority. Conflicting results were reported on the roles of the pGC-A (particulate guanylyl cyclase A receptor) and NP clearance receptor in aldosterone inhibition. Furthermore, the function of PKG (protein kinase G) and PDEs (phosphodiesterases) on aldosterone regulation are not clear. METHODS In the present study, we investigated the molecular mechanism of aldosterone regulation in a human adrenocortical cell line H295R and in mice. RESULTS We first provided evidence to show that pGC-A, not NP clearance receptor, mediates aldosterone inhibition. Next, we confirmed that MANP inhibits aldosterone via PDE2 (phosphodiesterase 2) not PKG, with specific agonists, antagonists, siRNA silencing, and fluorescence resonance energy transfer experiments. Further, the inhibitory effect is mediated by a reduction of intracellular Ca2+ levels. We then illustrated that MANP directly reduces aldosterone synthase CYP11B2 (cytochrome p450 family 11 subfamily b member 2) expression via PDE2. Last, in PDE2 knockout mice, consistent with in vitro findings, embryonic adrenal CYP11B2 is markedly increased. CONCLUSIONS Our results innovatively explore and expand the NP/pGC-A/3',5', cyclic guanosine monophosphate (cGMP)/PDE2 pathway for aldosterone inhibition by MANP in vitro and in vivo. In addition, our data also support the development of MANP as a novel ANP analog drug for aldosterone excess treatment.
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Affiliation(s)
- Yang Chen
- Cardiorenal Research Laboratory, Department of Cardiovascular Medicine (Y.C., S.R.I., X.M., J.C.B.), Mayo Clinic, Rochester MN.,The Institute for Diabetes' Obesity' and Metabolism, University of Pennsylvania, Philadelphia (Y.C.)
| | - Seethalakshmi R Iyer
- Cardiorenal Research Laboratory, Department of Cardiovascular Medicine (Y.C., S.R.I., X.M., J.C.B.), Mayo Clinic, Rochester MN
| | - Viacheslav O Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Germany (V.O.N.)
| | - Fabio Naro
- Department of Anatomical, Histological, Forensic and Orthopaedic Sciences, Sapienza University of Rome, Italy (F.N.' S.C.)
| | - Manuela Pellegrini
- Institute of Biochemistry and Cell Biology, IBBC-CNR, Monterotondo, Rome, Italy (M.P.)
| | - Silvia Cardarelli
- Department of Anatomical, Histological, Forensic and Orthopaedic Sciences, Sapienza University of Rome, Italy (F.N.' S.C.)
| | - Xiao Ma
- Cardiorenal Research Laboratory, Department of Cardiovascular Medicine (Y.C., S.R.I., X.M., J.C.B.), Mayo Clinic, Rochester MN
| | - Hon-Chi Lee
- Department of Cardiovascular Medicine (H.-C.L.), Mayo Clinic, Rochester MN
| | - John C Burnett
- Cardiorenal Research Laboratory, Department of Cardiovascular Medicine (Y.C., S.R.I., X.M., J.C.B.), Mayo Clinic, Rochester MN
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Hu L, Chen Y, Zhou X, Hoek M, Cox J, Lin K, Liu Y, Blumenschein W, Grein J, Swaminath G. Effects of soluble guanylate cyclase stimulator on renal function in ZSF-1 model of diabetic nephropathy. PLoS One 2022; 17:e0261000. [PMID: 35085251 PMCID: PMC8794189 DOI: 10.1371/journal.pone.0261000] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 11/23/2021] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Diabetic nephropathy is associated with endothelial dysfunction and oxidative stress, in which the nitric oxide-soluble guanylate cyclase-cyclic guanosine monophosphate (NO-sGC-cGMP) signaling pathway is impaired. We hypothesize that sGC stimulator Compound 1 can enhance NO signaling, reduce proteinuria in a diabetic nephropathy preclinical model with diminished NO bioavailability and increased oxidized sGC. Therefore, we evaluated the effect of sGC stimulator Compound 1 on the renal effect in obese ZSF1 (ZSF1 OB) rats. MATERIALS AND METHODS The sGC stimulator Compound 1, the standard of care agent Enalapril, and a combination of Compound 1 and Enalapril were administered chronically to obese ZSF1 rats for 6 months. Mean arterial pressure, heart rate, creatinine clearance for glomerular filtration rate (eGFR), urinary protein excretion to creatinine ratio (UPCR), and urinary albumin excretion ratio (UACR) were determined during the study. The histopathology of glomerular and interstitial lesions was assessed at the completion of the study. RESULTS While both Compound 1 and Enalapril significantly reduced blood pressure, the combination of Compound 1 and Enalapril normalized blood pressure levels. Compound 1 improved eGFR and reduced UPCR and UACR. A combination of Enalapril and Compound 1 resulted in a marked reduction in UPCR and UACR and improved GFR. CONCLUSION The sGC stimulator Compound 1 as a monotherapy slowed renal disease progression, and a combination of the sGC stimulator with Enalapril provided greater renal protection in a rodent model of diabetic nephropathy.
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Affiliation(s)
- Lufei Hu
- Department of Cardiometabolic Diseases, Merck & Co., Inc., Kenilworth, NJ, United States of America
| | - Yinhong Chen
- Department of Cardiometabolic Diseases, Merck & Co., Inc., Kenilworth, NJ, United States of America
| | - Xiaoyan Zhou
- Quantitative Biosciences, Merck & Co., Inc., Kenilworth, NJ, United States of America
| | - Maarten Hoek
- Department of Cardiometabolic Diseases, Merck & Co., Inc., Kenilworth, NJ, United States of America
- Biology Department, Maze Therapeutics, San Francisco, CA, United States of America
| | - Jason Cox
- Chemistry, Merck & Co., Inc., Kenilworth, NJ, United States of America
- Discovery Chemistry, Kinnate Biopharma, San Diego, CA, United States of America
| | - Ken Lin
- Pharmacokinetics, Pharmacodynamics & Drug Metabolism, Merck & Co., Inc., Kenilworth, NJ, United States of America
- Drug Metabolism and Pharmacokinetics, BridgeBio, Palo Alto, CA, United States of America
| | - Yang Liu
- Department of Cardiometabolic Diseases, Merck & Co., Inc., Kenilworth, NJ, United States of America
| | - Wendy Blumenschein
- Department of Molecular Discovery Profiling and Expression, Merck & Co. Inc., Kenilworth, NJ, United States of America
| | - Jeff Grein
- Department of Molecular Discovery Profiling and Expression, Merck & Co. Inc., Kenilworth, NJ, United States of America
| | - Gayathri Swaminath
- Department of Cardiometabolic Diseases, Merck & Co., Inc., Kenilworth, NJ, United States of America
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Shpakova V, Rukoyatkina N, Walter U, Gambaryan S. Potential and limitations of PKA/ PKG inhibitors for platelet studies. Platelets 2021; 33:859-868. [PMID: 34845961 DOI: 10.1080/09537104.2021.2003316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Cyclic nucleotides (cAMP and cGMP) and corresponding protein kinases, protein kinase A (PKA) and protein kinase G (PKG), are the main intracellular mediators of endothelium-derived platelet inhibitors. Pharmacological PKA/PKG inhibitors are often used to discriminate between these two kinase activities and to analyze their underlying mechanisms. Previously we showed that all widely used PKG inhibitors (KT5823, DT3, RP isomers) either did not inhibit PKG or inhibited and even activated platelets independently from PKG. In this study, we examined several PKA inhibitors as well as inhibitors of adenylate and guanylate cyclases to reveal their effects on platelets and establish whether they are mediated by PKA/PKG. The commonly used PKA inhibitor H89 inhibited both PKA and PKG but PKA-independently inhibited thrombin-induced platelet activation. In our experiments, KT5720 did not inhibit PKA and had no effect on platelet activation. PKI inhibited PKA activity in platelets but also strongly PKA-independently activated platelets. Inhibition of adenylate and guanylate cyclases may be an alternative approach to analyze PKA/PKG function. Based on our previous and presented data, we conclude that all results where the mentioned PKA inhibitors were used for the analysis of PKA activity in intact platelets should be considered with caution.
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Affiliation(s)
- Valentina Shpakova
- Laboratory of cellular mechanisms of blood homeostasis, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
| | - Natalia Rukoyatkina
- Laboratory of cellular mechanisms of blood homeostasis, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
| | - Ulrich Walter
- Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Stepan Gambaryan
- Laboratory of cellular mechanisms of blood homeostasis, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
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7
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Ngowi EE, Sarfraz M, Afzal A, Khan NH, Khattak S, Zhang X, Li T, Duan SF, Ji XY, Wu DD. Roles of Hydrogen Sulfide Donors in Common Kidney Diseases. Front Pharmacol 2020; 11:564281. [PMID: 33364941 PMCID: PMC7751760 DOI: 10.3389/fphar.2020.564281] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 09/30/2020] [Indexed: 12/15/2022] Open
Abstract
Hydrogen sulfide (H2S) plays a key role in the regulation of physiological processes in mammals. The decline in H2S level has been reported in numerous renal disorders. In animal models of renal disorders, treatment with H2S donors could restore H2S levels and improve renal functions. H2S donors suppress renal dysfunction by regulating autophagy, apoptosis, oxidative stress, and inflammation through multiple signaling pathways, such as TRL4/NLRP3, AMP-activated protein kinase/mammalian target of rapamycin, transforming growth factor-β1/Smad3, extracellular signal-regulated protein kinases 1/2, mitogen-activated protein kinase, and nuclear factor kappa B. In this review, we summarize recent developments in the effects of H2S donors on the treatment of common renal diseases, including acute/chronic kidney disease, renal fibrosis, unilateral ureteral obstruction, glomerulosclerosis, diabetic nephropathy, hyperhomocysteinemia, drug-induced nephrotoxicity, metal-induced nephrotoxicity, and urolithiasis. Novel H2S donors can be designed and applied in the treatment of common renal diseases.
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Affiliation(s)
- Ebenezeri Erasto Ngowi
- School of Basic Medical Sciences, Henan University, Kaifeng, China
- Henan International Joint Laboratory for Nuclear Protein Regulation, Henan University, Kaifeng, China
- Department of Biological Sciences, Faculty of Science, Dar es Salaam University College of Education, Dar es Salaam, Tanzania
| | - Muhammad Sarfraz
- School of Basic Medical Sciences, Henan University, Kaifeng, China
- Henan International Joint Laboratory for Nuclear Protein Regulation, Henan University, Kaifeng, China
- Kaifeng Municipal Key Laboratory of Cell Signal Transduction, Henan Provincial Engineering Centre for Tumor Molecular Medicine, Henan University, Kaifeng, China
- Faculty of Pharmacy, The University of Lahore, Lahore, Pakistan
| | - Attia Afzal
- School of Basic Medical Sciences, Henan University, Kaifeng, China
- Henan International Joint Laboratory for Nuclear Protein Regulation, Henan University, Kaifeng, China
- Faculty of Pharmacy, The University of Lahore, Lahore, Pakistan
| | - Nazeer Hussain Khan
- Henan International Joint Laboratory for Nuclear Protein Regulation, Henan University, Kaifeng, China
- College of Pharmacy, Henan University, Kaifeng, China
| | - Saadullah Khattak
- School of Basic Medical Sciences, Henan University, Kaifeng, China
- Henan International Joint Laboratory for Nuclear Protein Regulation, Henan University, Kaifeng, China
| | - Xin Zhang
- College of Pharmacy, Henan University, Kaifeng, China
- Institute for Innovative Drug Design and Evaluation, School of Pharmacy, Henan University, Kaifeng, China
| | - Tao Li
- School of Basic Medical Sciences, Henan University, Kaifeng, China
- Henan International Joint Laboratory for Nuclear Protein Regulation, Henan University, Kaifeng, China
| | - Shao-Feng Duan
- Henan International Joint Laboratory for Nuclear Protein Regulation, Henan University, Kaifeng, China
- College of Pharmacy, Henan University, Kaifeng, China
- Institute for Innovative Drug Design and Evaluation, School of Pharmacy, Henan University, Kaifeng, China
| | - Xin-Ying Ji
- School of Basic Medical Sciences, Henan University, Kaifeng, China
- Henan International Joint Laboratory for Nuclear Protein Regulation, Henan University, Kaifeng, China
- Diseases and Bio-Safety, School of Basic Medical Sciences, Henan University, Kaifeng, China
| | - Dong-Dong Wu
- School of Basic Medical Sciences, Henan University, Kaifeng, China
- Henan International Joint Laboratory for Nuclear Protein Regulation, Henan University, Kaifeng, China
- School of Stomatology, Henan University, Kaifeng, China
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Díaz-González F, Wadhwa S, Rodriguez-Zabala M, Kumar S, Aza-Carmona M, Sentchordi-Montané L, Alonso M, Ahmad I, Zahra S, Kumar D, Kushwah N, Shamim U, Sait H, Kapoor S, Roldán B, Nishimura G, Offiah AC, Faruq M, Heath KE. Biallelic cGMP-dependent type II protein kinase gene (PRKG2) variants cause a novel acromesomelic dysplasia. J Med Genet 2020; 59:28-38. [DOI: 10.1136/jmedgenet-2020-107177] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 09/22/2020] [Accepted: 09/23/2020] [Indexed: 12/12/2022]
Abstract
BackgroundC-type natriuretic peptide (CNP), its endogenous receptor, natriuretic peptide receptor-B (NPR-B), as well as its downstream mediator, cyclic guanosine monophosphate (cGMP) dependent protein kinase II (cGKII), have been shown to play a pivotal role in chondrogenic differentiation and endochondral bone growth. In humans, biallelic variants in NPR2, encoding NPR-B, cause acromesomelic dysplasia, type Maroteaux, while heterozygous variants in NPR2 (natriuretic peptide receptor 2) and NPPC (natriuretic peptide precursor C), encoding CNP, cause milder phenotypes. In contrast, no variants in cGKII, encoded by the protein kinase cGMP-dependent type II gene (PRKG2), have been reported in humans to date, although its role in longitudinal growth has been clearly demonstrated in several animal models.MethodsExome sequencing was performed in two girls with severe short stature due to acromesomelic limb shortening, brachydactyly, mild to moderate platyspondyly and progressively increasing metaphyseal alterations of the long bones. Functional characterisation was undertaken for the identified variants.ResultsTwo homozygous PRKG2 variants, a nonsense and a frameshift, were identified. The mutant transcripts are exposed to nonsense-mediated decay and the truncated mutant cGKII proteins, partially or completely lacking the kinase domain, alter the downstream mitogen activation protein kinase signalling pathway by failing to phosphorylate c-Raf 1 at Ser43 and subsequently reduce ERK1/2 activation in response to fibroblast growth factor 2. They also downregulate COL10A1 and upregulate COL2A1 expression through SOX9.ConclusionIn conclusion, we have clinically and molecularly characterised a new acromesomelic dysplasia, acromesomelic dysplasia, PRKG2 type (AMDP).
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Tugaeva KV, Titterington J, Sotnikov DV, Maksimov EG, Antson AA, Sluchanko NN. Molecular basis for the recognition of steroidogenic acute regulatory protein by the 14‐3‐3 protein family. FEBS J 2020; 287:3944-3966. [DOI: 10.1111/febs.15474] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/26/2020] [Accepted: 07/01/2020] [Indexed: 11/30/2022]
Affiliation(s)
- Kristina V. Tugaeva
- Federal Research Center of Biotechnology of the Russian Academy of Sciences A.N. Bach Institute of Biochemistry Moscow Russia
- Department of Biochemistry School of Biology M.V. Lomonosov Moscow State University Russia
| | - James Titterington
- York Structural Biology Laboratory Department of Chemistry University of York UK
| | - Dmitriy V. Sotnikov
- Federal Research Center of Biotechnology of the Russian Academy of Sciences A.N. Bach Institute of Biochemistry Moscow Russia
| | - Eugene G. Maksimov
- Federal Research Center of Biotechnology of the Russian Academy of Sciences A.N. Bach Institute of Biochemistry Moscow Russia
- Department of Biophysics School of Biology M.V. Lomonosov Moscow State University Russia
| | - Alfred A. Antson
- York Structural Biology Laboratory Department of Chemistry University of York UK
| | - Nikolai N. Sluchanko
- Federal Research Center of Biotechnology of the Russian Academy of Sciences A.N. Bach Institute of Biochemistry Moscow Russia
- Department of Biophysics School of Biology M.V. Lomonosov Moscow State University Russia
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Schramm A, Schweda F, Sequeira-Lopez MLS, Hofmann F, Sandner P, Schlossmann J. Protein Kinase G Is Involved in Acute but Not in Long-Term Regulation of Renin Secretion. Front Pharmacol 2019; 10:800. [PMID: 31379575 PMCID: PMC6657341 DOI: 10.3389/fphar.2019.00800] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 06/21/2019] [Indexed: 12/27/2022] Open
Abstract
Pharmacological inhibition of the renin–angiotensin–aldosterone system (RAAS) is, in combination with diuretics, the first-choice treatment for hypertension, although 10–20% of patients do not respond adequately. Next to the RAAS, the nitric oxide/cGMP/protein kinase G (PKG) system is the second fundamental blood pressure regulator. Whether both systems influence each other is not well-studied. It has been shown that nitric oxide (NO) supports renin recruitment via activation of soluble guanylate cyclase (sGC) and subsequent generation of cGMP. Whether this leads to an ensuing activation of PKGs in this context is not known. PKGIα, as well as PKGII, is expressed in renin-producing cells. Hence, we analyzed whether these enzymes play a role regarding renin synthesis, secretion, or recruitment. We generated renin-cell-specific PKGI-knockout mice and either stimulated or inhibited the renin system in these mice by salt diets. To exclude the possibility that one kinase isoform can compensate the lack of the other, we also studied double-knockout animals with a conditional knockout of PKGI in juxtaglomerular cells (JG cells) and a ubiquitous knockout of PKGII. We analyzed blood pressure, renin mRNA and renal renin protein content as well as plasma renin concentration. Furthermore, we stimulated the cGMP system in these mice using BAY 41-8543, an sGC stimulator, and examined renin regulation either after acute administration or after 7 days (application once daily). We did not reveal any striking differences regarding long-term renin regulation in the studied mouse models. Yet, when we studied the acute effect of BAY 41-8543 on renin secretion in isolated perfused kidneys as well as in living animals, we found that the administration of the substance led to a significant increase in plasma renin concentration in control animals. This effect was completely abolished in double-knockout animals. However, after 7 days of once daily application, we did not detect a persistent increase in renin mRNA or protein in any studied genotype. Therefore, we conclude that in mice, cGMP and PKG are involved in the acute regulation of renin release but have no influence on long-term renin adjustment.
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Affiliation(s)
- Andrea Schramm
- Institute of Pharmacy, Department of Pharmacology and Toxicology, University of Regensburg, Regensburg, Germany
| | - Frank Schweda
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | | | - Franz Hofmann
- Institute of Pharmacology and Toxicology, Technical University of Munich, Munich, Germany
| | - Peter Sandner
- Bayer AG, Drug Discovery-Cardiology, Wuppertal, Germany
| | - Jens Schlossmann
- Institute of Pharmacy, Department of Pharmacology and Toxicology, University of Regensburg, Regensburg, Germany
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11
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Genetic variants of cGMP-dependent protein kinase genes and salt sensitivity of blood pressure: the GenSalt study. J Hum Hypertens 2018; 33:62-68. [DOI: 10.1038/s41371-018-0099-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 07/16/2018] [Accepted: 08/06/2018] [Indexed: 11/08/2022]
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Sokanovic SJ, Capo I, Medar MM, Andric SA, Kostic TS. Long-term inhibition of PDE5 ameliorates aging-induced changes in rat testis. Exp Gerontol 2018; 108:139-148. [PMID: 29660387 DOI: 10.1016/j.exger.2018.04.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/06/2018] [Accepted: 04/08/2018] [Indexed: 01/01/2023]
Abstract
NO-cGMP signaling pathway has been implicated in reduction of testicular steroidogenesis during aging. Here we analyzed the effect of PDE5 inhibition on old testicular phenotype formation. The old phenotype exhibited low testosterone and increased nitrite levels in circulation, increased cGMP accumulation in testicular interstitial fluid (TIF), progressive atrophy of testicular seminiferous tubules and enlargement of interstitial area followed by rise in blood vessel density and slight increase in the number of Leydig cells and macrophages. Leydig cells have reduced steroidogenic capacity, increased MAP kinases expression (MEK, ERK1/2, JNK) and antiapoptotic PRKG1 and AKT, suggesting increased proliferation/survival and accumulation of senescent Leydig cells in testis. In 12 month-old rats, a long-term treatment with sildenafil (PDE5 inhibitor) normalized testosterone/nitrite levels in circulation and cGMP accumulation in TIF; improved Leydig cell steroidogenic capacity; decreased MEK, ERK1/2 and PRKG1 expression; prevented an increase in the Leydig cells number and atrophy of seminiferous tubules leading to histological appearance of young rat testes. In 18 month-old rats, long-term PDE5 inhibition partially recovered testosterone and nitrite levels in serum; normalized PRKG1 expression without effect on MEK and ERK1/2; and slowed down Leydig cell and macrophage accumulation and regressive tubular changes. Culturing of primary Leydig cells from aged rats in presence of PDE5-inhibitor stimulated steroidogenic and MAPK gene expression. Taking together, results indicate that cGMP targeting alter both steroidogenesis and signaling pathways associated with cell proliferation/survival. The long-term PDE5 inhibition improves testicular steroidogenesis and slows-down regressive changes in testes during aging.
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Affiliation(s)
- Srdjan J Sokanovic
- Laboratory for Reproductive Endocrinology and Signaling, Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, Novi Sad, Serbia
| | - Ivan Capo
- Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
| | - Marija M Medar
- Laboratory for Reproductive Endocrinology and Signaling, Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, Novi Sad, Serbia
| | - Silvana A Andric
- Laboratory for Reproductive Endocrinology and Signaling, Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, Novi Sad, Serbia
| | - Tatjana S Kostic
- Laboratory for Reproductive Endocrinology and Signaling, Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, Novi Sad, Serbia.
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Transepithelial Fluid and Salt Re-Absorption Regulated by cGK2 Signals. Int J Mol Sci 2018; 19:ijms19030881. [PMID: 29547542 PMCID: PMC5877742 DOI: 10.3390/ijms19030881] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 02/12/2018] [Accepted: 03/14/2018] [Indexed: 12/23/2022] Open
Abstract
Transepithelial fluid and salt re-absorption in epithelial tissues play an important role in fluid and salt homeostasis. In absorptive epithelium, fluid and salt flux is controlled by machinery mainly composed of epithelial sodium channels (ENaC), cystic fibrosis transmembrane conductance regulator (CFTR), Na⁺/H⁺ exchanger (NHE), aquaporin, and sodium potassium adenosine triphosphatase (Na⁺/K⁺-ATPase). Dysregulation of fluid and salt transport across epithelium contributes to the pathogenesis of many diseases, such as pulmonary edema and cystic fibrosis. Intracellular and extracellular signals, i.e., hormones and protein kinases, regulate fluid and salt turnover and resolution. Increasing evidence demonstrates that transepithelial fluid transport is regulated by cyclic guanosine monophosphate-dependent protein kinase (cGK) signals. cGK2 was originally identified and cloned from intestinal specimens, the presence of which has also been confirmed in the kidney and the lung. cGK2 regulates fluid and salt through ENaC, CFTR and NHE. Deficient cGK2 regulation of transepithelial ion transport was seen in acute lung injury, and cGK2 could be a novel druggable target to restore edematous disorder in epithelial tissues.
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Aging has the opposite effect on cAMP and cGMP circadian variations in rat Leydig cells. J Comp Physiol B 2016; 187:613-623. [PMID: 27915366 DOI: 10.1007/s00360-016-1052-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 11/08/2016] [Accepted: 11/23/2016] [Indexed: 01/20/2023]
Abstract
The Leydig cell physiology displays a circadian rhythm driven by a complex interaction of the reproductive axis hormones and circadian system. The final output of this regulatory process is circadian pattern of steroidogenic genes expression and testosterone production. Aging gradually decreases robustness of rhythmic testosterone secretion without change in pattern of LH secretion. Here, we analyzed effect of aging on circadian variation of cAMP and cGMP signaling in Leydig cells. Results showed opposite effect of aging on cAMP and cGMP daily variation. Reduced amplitude of cAMP circadian oscillation was probably associated with changed expression of genes involved in cAMP production (increased circadian pattern of Adcy7, Adcy9, Adcy10 and decreased Adcy3); cAMP degradation (increased Pde4a, decreased Pde8b, canceled rhythm of Pde4d, completely reversed circadian pattern of Pde7b and Pde8a); and circadian expression of protein kinase A subunits (Prkac/PRKAC and Prkar2a). Aging stimulates expression of genes responsible for cGMP production (Nos2, Gucy1a3 and Gucy1b3/GUCYB3) and degradation (Pde5a, Pde6a and Pde6h) but the overall net effect is elevation of cGMP circadian oscillations in Leydig cells. In addition, the expression of cGMP-dependent kinase, Prkg1/PRKG1 is up-regulated. It seems that aging potentiate cGMP- and reduce cAMP-signaling in Leydig cells. Since both signaling pathways affect testosterone production and clockwork in the cells, further insights into these signaling pathways will help to unravel disorders linked to the circadian timing system, aging and reproduction.
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15
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Chen YJ, Wang L, Zhou GY, Yu XL, Zhang YH, Hu N, Li QQ, Chen C, Qing C, Liu YT, Yang WM. Scutellarin attenuates endothelium-dependent aasodilation impairment induced by hypoxia reoxygenation, through regulating the PKG signaling pathway in rat coronary artery. Chin J Nat Med 2016; 13:264-73. [PMID: 25908623 DOI: 10.1016/s1875-5364(15)30013-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Indexed: 11/19/2022]
Abstract
Scutellarin (SCU), a flavonoid from a traditional Chinese medicinal plant. Our previous study has demonstrated that SCU relaxes mouse aortic arteries mainly in an endothelium-depend-ent manner. In the present study, we investigated the vasoprotective effects of SCU against HR-induced endothelial dysfunction (ED) in isolated rat CA and the possible mechanisms involving cyclic guanosine monophosphate (cGMP) dependent protein kinase (PKG). The isolated endothelium-intact and endothelium-denuded rat CA rings were treated with HR injury. Evaluation of endothelium-dependent and -independent vasodilation relaxation of the CA rings were performed using wire myography and the protein expressions were assayed by Western blotting. SCU (10-1 000 μmol·L(-1)) could relax the endothelium-intact CA rings but not endothelium-denuded ones. In the intact CA rings, the PKG inhibitor, Rp-8-Br-cGMPS (PKGI-rp, 4 μmol·L(-1)), significantly blocked SCU (10-1 000 μmol·L(-1))-induced relaxation. The NO synthase (NOS) inhibitor, NO-nitro-L-arginine methylester (L-NAME, 100 μmol·L(-1)), did not significantly change the effects of SCU (10-1 000 μmol·L(-1)). HR treatment significantly impaired ACh-induced relaxation, which was reversed by pre-incubation with SCU (500 μmol·L(-1)), while HR treatment did not altered NTG-induced vasodilation. PKGI-rp (4 μmol·L(-1)) blocked the protective effects of SCU in HR-treated CA rings. Additionally, HR treatment reduced phosphorylated vasodilator-stimulated phosphoprotein (p-VASP, phosphorylated product of PKG), which was reversed by SCU pre-incubation, suggesting that SCU activated PKG phosphorylation against HR injury. SCU induces CA vasodilation in an endothelium-dependent manner to and repairs HR-induced impairment via activation of PKG signaling pathway.
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Affiliation(s)
- Ya-Juan Chen
- School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming 650500, China
| | - Lei Wang
- School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming 650500, China
| | - Guang-Yu Zhou
- School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming 650500, China
| | - Xian-Lun Yu
- Zhaotong Institute of Tianma, Zhaotong 657000, China
| | - Yong-Hui Zhang
- School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming 650500, China
| | - Na Hu
- School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming 650500, China
| | - Qing-Qing Li
- School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming 650500, China
| | - Chen Chen
- School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming 650500, China
| | - Chen Qing
- School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming 650500, China
| | - Ying-Ting Liu
- Department of Periodontology and Implant Dentistry, The First People's Hospital of Yun-Nan Province, Kunhua Hospital Affiliated to Kunming University of Science and Technology, Kunming 650032, China.
| | - Wei-Min Yang
- School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming 650500, China.
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Corona G, Ratrelli G, Maggi M. The pharmacotherapy of male hypogonadism besides androgens. Expert Opin Pharmacother 2014; 16:369-87. [DOI: 10.1517/14656566.2015.993607] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Giovanni Corona
- 1University of Florence, Maggiore-Bellaria Hospital, Medical Department, Endocrinology Unit, Azienda-Usl Bologna, Bologna, Italy
| | - Giulia Ratrelli
- 2University of Florence, Department of Experimental, Clinical and Biomedical Sciences, Sexual Medicine and Andrology Unit, Florence, Italy; ;
| | - Mario Maggi
- 2University of Florence, Department of Experimental, Clinical and Biomedical Sciences, Sexual Medicine and Andrology Unit, Florence, Italy; ;
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17
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Sokanovic SJ, Baburski AZ, Janjic MM, Stojkov NJ, Bjelic MM, Lalosevic D, Andric SA, Stojilkovic SS, Kostic TS. The opposing roles of nitric oxide and cGMP in the age-associated decline in rat testicular steroidogenesis. Endocrinology 2013; 154:3914-24. [PMID: 23885018 PMCID: PMC3776867 DOI: 10.1210/en.2013-1307] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The molecular mechanism of the aging-associated dysfunction of Leydig cells (LCs) is complex and poorly understood. In this study, we analyzed the contribution of nitric oxide (NO) and cGMP signaling to the age-dependent decline in LC function. Significant (>50%) decreases in serum, intratesticular, and LC androgens in aging rats (15-24 months) were accompanied by a proportional increase in NO production, an up-regulation of cGMP levels, and the expression of soluble guanylyl cyclase-1B and protein kinase G1 in LCs. In contrast, LC cAMP levels decreased with age, most likely reflecting the up-regulation of cAMP-specific phosphodiesterase expression. Moreover, the expression of genes encoding enzymes responsible for cholesterol transport and its conversion to T were reduced. Exposing LCs from aged animals to NO further increased cGMP levels and decreased cAMP and androgen production, whereas the addition of cell-permeable 8-bromoguanosine-cGMP alone had the opposite effect. In vivo inhibition of cGMP-specific phosphodiesterase-5 for 3 and 6 months in aged rats led to a partial restoration of androgens, NO, and cyclic nucleotide levels, as well as the expression of steroidogenic and NO/cGMP signaling genes. These results indicate that a progressive increase in NO production contributes to the age-dependent decrease in steroidogenesis in a cGMP-independent manner, whereas the sustained elevation in cGMP levels significantly slows the decline in LC function.
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Affiliation(s)
- Srdjan J Sokanovic
- PhD, Reproductive Endocrinology and Signaling Group, University of Novi Sad, Novi Sad 21000, Serbia.
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18
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Thoonen R, Sips PY, Bloch KD, Buys ES. Pathophysiology of hypertension in the absence of nitric oxide/cyclic GMP signaling. Curr Hypertens Rep 2013; 15:47-58. [PMID: 23233080 DOI: 10.1007/s11906-012-0320-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) signaling system is a well-characterized modulator of cardiovascular function, in general, and blood pressure, in particular. The availability of mice mutant for key enzymes in the NO-cGMP signaling system facilitated the identification of interactions with other blood pressure modifying pathways (e.g. the renin-angiotensin-aldosterone system) and of gender-specific effects of impaired NO-cGMP signaling. In addition, recent genome-wide association studies identified blood pressure-modifying genetic variants in genes that modulate NO and cGMP levels. Together, these findings have advanced our understanding of how NO-cGMP signaling regulates blood pressure. In this review, we will summarize the results obtained in mice with disrupted NO-cGMP signaling and highlight the relevance of this pathway as a potential therapeutic target for the treatment of hypertension.
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Affiliation(s)
- Robrecht Thoonen
- Molecular Cardiology Research Institute, Molecular Cardiology Research Center, Tufts Medical Center, Boston, MA 02111, USA.
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19
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Gambaryan S, Butt E, Kobsar A, Geiger J, Rukoyatkina N, Parnova R, Nikolaev VO, Walter U. The oligopeptide DT-2 is a specific PKG I inhibitor only in vitro, not in living cells. Br J Pharmacol 2013; 167:826-38. [PMID: 22612416 DOI: 10.1111/j.1476-5381.2012.02044.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE cGMP is involved in the regulation of many cellular processes including cardiac and smooth muscle contractility, aldosterone synthesis and inhibition of platelet activation. Intracellular effects cGMP are mediated by cGMP-dependent PKs, cGMP-regulated PDEs and cGMP-gated ion channels. PKG inhibitors are widely used to discriminate PKG-specific effects. They can be divided into cyclic nucleotide-binding site inhibitors such as Rp-phosphorothioate analogues (Rp-cGMPS), ATP-binding site inhibitors such as KT5823, and substrate binding site inhibitors represented by the recently described DT-oligopeptides. As it has been shown that Rp-cGMPS and KT5823 have numerous non-specific effects, we analysed the pharmacological properties of the oligopeptide (D)-DT-2 described as a highly specific, membrane-permeable, PKG inhibitor. EXPERIMENTAL APPROACH Specificity and potency of (D)-DT-2 to inhibit PKG activity was evaluated using biochemical assays in vitro and by substrate phosphorylation analysis in various cell types including human platelets, rat mesangial cells and rat neonatal cardiomyocytes. KEY RESULTS Despite potent inhibition of PKGI in vitro, (D)-DT-2 lost specificity for PKG in cell homogenates and particularly in living cells, as demonstrated by phosphorylation of different substrates. Instead, (D)-DT-2 modulated activity of other kinases including ERK, p38, PKB and PKC, thereby inducing unpredicted and often opposing functional effects. CONCLUSIONS AND IMPLICATIONS We conclude that DT-oligopeptides, as other inhibitors, cannot be used to specifically inhibit PKG in intact cells. Therefore, no specific pharmacological PKG inhibitors are available, and reliable studies of PKG signalling can only be made by using RNA knockdown or genetic deletion methods.
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Affiliation(s)
- Stepan Gambaryan
- Institute of Clinical Biochemistry and Pathobiochemistry, University of Wuerzburg, Wuerzburg, Germany.
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Abstract
cGMP-dependent protein kinases (cGK) are serine/threonine kinases that are widely distributed in eukaryotes. Two genes-prkg1 and prkg2-code for cGKs, namely, cGKI and cGKII. In mammals, two isozymes, cGKIα and cGKIβ, are generated from the prkg1 gene. The cGKI isozymes are prominent in all types of smooth muscle, platelets, and specific neuronal areas such as cerebellar Purkinje cells, hippocampal neurons, and the lateral amygdala. The cGKII prevails in the secretory epithelium of the small intestine, the juxtaglomerular cells, the adrenal cortex, the chondrocytes, and in the nucleus suprachiasmaticus. Both cGKs are major downstream effectors of many, but not all, signalling events of the NO/cGMP and the ANP/cGMP pathways. cGKI relaxes smooth muscle tone and prevents platelet aggregation, whereas cGKII inhibits renin secretion, chloride/water secretion in the small intestine, the resetting of the clock during early night, and endochondral bone growth. This chapter focuses on the involvement of cGKs in cardiovascular and non-cardiovascular processes including cell growth and metabolism.
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Affiliation(s)
- Franz Hofmann
- FOR 923, Institut für Pharmakologie und Toxikologie, der Technischen Universität München, Munich, Germany
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21
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Sickling cells, cyclic nucleotides, and protein kinases: the pathophysiology of urogenital disorders in sickle cell anemia. Anemia 2012; 2012:723520. [PMID: 22745902 PMCID: PMC3382378 DOI: 10.1155/2012/723520] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 04/16/2012] [Accepted: 04/22/2012] [Indexed: 02/01/2023] Open
Abstract
Sickle cell anemia is one of the best studied inherited diseases, and despite being caused by a single point mutation in the HBB gene, multiple pleiotropic effects of the abnormal hemoglobin S production range from vaso-occlusive crisis, stroke, and pulmonary hypertension to osteonecrosis and leg ulcers. Urogenital function is not spared, and although priapism is most frequently remembered, other related clinical manifestations have been described, such as nocturia, enuresis, increased frequence of lower urinary tract infections, urinary incontinence, hypogonadism, and testicular infarction. Studies on sickle cell vaso-occlusion and priapism using both in vitro and in vivo models have shed light on the pathogenesis of some of these events. The authors review what is known about the deleterious effects of sickling on the genitourinary tract and how the role of cyclic nucleotides signaling and protein kinases may help understand the pathophysiology underlying these manifestations and develop novel therapies in the setting of urogenital disorders in sickle cell disease.
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22
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Stojkov NJ, Janjic MM, Bjelic MM, Mihajlovic AI, Kostic TS, Andric SA. Repeated immobilization stress disturbed steroidogenic machinery and stimulated the expression of cAMP signaling elements and adrenergic receptors in Leydig cells. Am J Physiol Endocrinol Metab 2012; 302:E1239-51. [PMID: 22374756 DOI: 10.1152/ajpendo.00554.2011] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
This study was designed to evaluate the effect of acute (2 h daily) and repeated (2 h daily for 2 or 10 consecutive days) immobilization stress (IMO) on: 1) the steroidogenic machinery homeostasis; 2) cAMP signaling; and the expression of receptors for main markers of 3) adrenergic and 4) glucocorticoid signaling in Leydig cells of adult rats. The results showed that acute IMO inhibited steroidogenic machinery in Leydig cells by downregulation of Scarb1 (scavenger receptor class B), Cyp11a1 (cholesterol side-chain cleavage enzyme), Cyp17a1 (17α-hydroxylase/17,20 lyase), and Hsd17b3 (17β-hydroxysteroid dehydrogenase) expression. In addition to acute IMO effects, repeated IMO increased transcription of Star (steroidogenic acute regulatory protein) and Arr19 (androgen receptor corepressor 19 kDa) in Leydig cells. In the same cells, the transcription of adenylyl cyclases (Adcy7, Adcy9, Adcy10) and cAMP-specific phosphodiesterases (Pde4a, Pde4b, Pde4d, Pde7a, Pde8a) was stimulated, whereas the expression of the genes encoding protein kinase A subunits were unaffected. Ten times repeated IMO increased the levels of all adrenergic receptors and β-adrenergic receptor kinase (Adrbk1) in Leydig cells. The transcription analysis was supported by cAMP/testosterone production. In this signaling scenario, partial recovery of testosterone production in medium/content was detected. The physiological significance of the present results was proven by ex vivo application of epinephrine, which increased cAMP/testosterone production by Leydig cells from control rats in greater fashion than from stressed. IMO did not affect the expression of transcripts for Crhr1/Crhr2 (corticotropin releasing hormone receptors), Acthr (adrenocorticotropin releasing hormone receptor), Gr (glucocorticoid receptor), and Hsd11b1 [hydroxysteroid (11-β) dehydrogenase 1], while all types of IMO stimulated the expression of Hsd11b2, the unidirectional oxidase with high affinity to inactivate glucocorticoids. Thus, presented data provide new molecular/transcriptional base for "fight/adaptation" of Leydig cells and new insights into the role of cAMP, epinephrine, and glucocorticoid signaling in recovery of stress-impaired Leydig cell steroidogenesis.
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MESH Headings
- 3',5'-Cyclic-AMP Phosphodiesterases/genetics
- 3',5'-Cyclic-AMP Phosphodiesterases/metabolism
- Adenylyl Cyclases/genetics
- Adenylyl Cyclases/metabolism
- Androgens/blood
- Animals
- Cholesterol Side-Chain Cleavage Enzyme/genetics
- Cholesterol Side-Chain Cleavage Enzyme/metabolism
- Corticosterone/blood
- Cyclic AMP/metabolism
- Leydig Cells/physiology
- Luteinizing Hormone/blood
- Male
- Rats
- Rats, Wistar
- Receptors, Adrenergic/metabolism
- Receptors, Adrenergic, alpha-1/genetics
- Receptors, Adrenergic, alpha-1/metabolism
- Restraint, Physical
- Scavenger Receptors, Class B/genetics
- Scavenger Receptors, Class B/metabolism
- Signal Transduction/physiology
- Steroid 17-alpha-Hydroxylase/genetics
- Steroid 17-alpha-Hydroxylase/metabolism
- Steroids/blood
- Stress, Physiological/physiology
- Transcription, Genetic/physiology
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Affiliation(s)
- Natasa J Stojkov
- Reproductive Endocrinology and Signaling Group, Dept. of Biology and Ecology, Faculty of Sciences at Univ. of Novi Sad, Dositeja Obradovica Square 2, 21000 Novi Sad, Serbia
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23
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Janjic MM, Stojkov NJ, Bjelic MM, Mihajlovic AI, Andric SA, Kostic TS. Transient rise of serum testosterone level after single sildenafil treatment of adult male rats. J Sex Med 2012; 9:2534-43. [PMID: 22429315 DOI: 10.1111/j.1743-6109.2012.02674.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Phosphodiesterase type 5 (PDE5) inhibitors have been established in therapy for a variety of physiological disorders including erectile dysfunction. Despite its popularity and wide usage in erectile dysfunction treatment, the short-term effect of PDE5 inhibition on Leydig cell functionality and testosterone dynamics is missing. AIM This study was designed to assess the acute in vivo effects of sildenafil citrate (Viagra) treatment on testosterone production. METHODS Male adult rats were given sildenafil (1.25 mg/kg BW) per os, and testosterone production were analyzed 30, 60, 120, and 180 minutes after treatment. Additionally, in vitro effect of sildenafil extract on Leydig cell steroidogenesis was estimated. MAIN OUTCOME MEASURES The formation of testicular interstitial fluid (TIF), and testosterone, cyclic guanosine monophosphate (cGMP), cyclic adenosine monophosphate (cAMP) content was followed. Occurrence and phosphorylation of mature steroidogenic acute regulatory protein (StAR) and interaction with protein kinase G 1 (PRKG1) were assessed by immunoprecipitation and Western blot. RESULTS Serum testosterone was increased 60 and 120 minutes after sildenafil treatment. In 60 minutes, TIF volume was doubled and stayed increased till the end of the experimental period. cGMP and testosterone content in TIF were increased 30 minutes after treatment, and cAMP decreased in 60 minutes. Further, sildenafil-induced stimulation of testosterone production was abolished by ex vivo addition of PRKG1 inhibitor but not by protein kinase A inhibitor. Sildenafil treatment increased the level of phosphorylated and total StAR protein. Moreover, co-immunoprecipitation of StAR and PRKG1 was increased following sildenafil treatment suggesting the active role of this kinase in initiation of testosterone synthesis. Additionally, sildenafil extract applied in vitro on primary Leydig cell culture increased cGMP accumulation and testosterone production in time- and dose-dependent manner without effect on cAMP level. CONCLUSION Acute sildenafil treatment enlarged TIF volume but also stimulated testosterone production which may be significant considering the positive testosterone effect in regulation of sexual activity.
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Affiliation(s)
- Marija M Janjic
- Reproductive Endocrinology and Signaling Group, Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, Novi Sad, Serbia
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24
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Tsai LCL, Beavo JA. The roles of cyclic nucleotide phosphodiesterases (PDEs) in steroidogenesis. Curr Opin Pharmacol 2011; 11:670-5. [PMID: 21962440 DOI: 10.1016/j.coph.2011.09.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 09/06/2011] [Accepted: 09/07/2011] [Indexed: 01/09/2023]
Abstract
The second messenger, cAMP, is one of the most important regulatory signals for control of steroidogenesis. This review focuses on current knowledge about regulation of cyclic nucleotides by phosphodiesterases (PDEs) in steroidogenic tissues. The first PDE known to directly regulate steroidogenesis was PDE2, the cGMP-stimulated PDE. PDE2 mediates ANP/cGMP-induced decreases in aldosterone production. Recently, the PDE8 family has been shown to control steroidogenesis in two tissues. Specifically, PDE8A regulates testosterone production by itself and in concert with additional IBMX-sensitive PDEs. PDE8B modulates basal corticosterone synthesis via acute and chronic mechanisms. In addition to cAMP-dependent pathways, cGMP signaling also can promote steroidogenesis, and PDE5 modulates this process. Finally, PDE mutations may lead to several human diseases characterized by abnormal steroid levels.
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Affiliation(s)
- Li-Chun Lisa Tsai
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
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25
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Zhang YW, Rudnick G. Myristoylation of cGMP-dependent protein kinase dictates isoform specificity for serotonin transporter regulation. J Biol Chem 2010; 286:2461-8. [PMID: 21097501 DOI: 10.1074/jbc.m110.203935] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
By transporting serotonin (5-HT) into neurons and other cells, serotonin transporter (SERT) modulates the action of 5-HT at cell surface receptors. SERT itself is modulated by several processes, including the cGMP signaling pathway. Activation of SERT by cGMP requires the cGMP-dependent protein kinase (PKG). Here we show that in HeLa cells lacking endogenous PKG, expression of PKGIα or PKGIβ was required for 8-bromoguanosine-3',5'-cyclic monophosphate (8-Br-cGMP) to stimulate SERT phosphorylation and 5-HT influx. Catalytically inactive PKG mutants and wild-type PKGII did not support this stimulation. However, a mutant PKGII (G2A) that was not myristoylated substituted for functional PKGI, suggesting that myristoylation and subsequent membrane association blocked productive interaction with SERT. PKG also influenced SERT expression and localization. PKGI isoforms increased total and cell surface SERT levels, and PKGII decreased cell surface SERT without altering total expression. Remarkably, these changes did not require 8-Br-cGMP or functional kinase activity and were also observed with a SERT mutant resistant to activation by PKG. Both PKGIα and PKGIβ formed detergent-stable complexes with SERT, and this association did not require catalytic activity. The nonmyristoylated PKGII G2A mutant stimulated SERT expression similar to PKGI isoforms. These results suggest multiple mechanisms by which PKG can modulate SERT and demonstrate that the functional difference between PKG isoforms results from myristoylation of PKGII.
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Affiliation(s)
- Yuan-Wei Zhang
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520-8066, USA
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Andric SA, Janjic MM, Stojkov NJ, Kostic TS. Sildenafil treatment in vivo stimulates Leydig cell steroidogenesis via the cAMP/cGMP signaling pathway. Am J Physiol Endocrinol Metab 2010; 299:E544-50. [PMID: 20663985 DOI: 10.1152/ajpendo.00337.2010] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sildenafil citrate (Viagra), a cGMP-selective phosphodiesterase (PDE) inhibitor, is widely used to treat erectile dysfunction and pulmonary arterial hypertension. In contrast to its well established action on erectile dysfunction, little is known on the action of sildenafil on cGMP/cAMP signaling and testicular steroidogenesis. This study was designed to assess the effects of prolonged sildenafil treatment on NO synthase-dependent signaling and steroidogenic function of rat Leydig cells. Male adult rats were treated with Viagra (1.25 mg/kg body wt) daily for 30 days. In our studies, serum testosterone and ex vivo testosterone production significantly increased in sildenafil-treated animals. Human chorionic gonadotropin-stimulated testosterone production and cAMP accumulation were also significantly higher in Leydig cells obtained from sildenafil-treated rats. The expression of soluble guanylyl cyclase (GUCY1) subunits (Gucy1a1, Gucy1b1) significantly increased; cAMP-specific Pde4a, cGMP-specific Pde6c, and dual Pde1c and Nos2 were inhibited and expression of Nos3, protein kinase G1 (Pkg1), and Pde5 remained unchanged. Treatment of purified Leydig cells with NO donor caused a dose-dependent increase in both testosterone and cGMP production. Testosterone and cGMP production was significantly higher in Leydig cells obtained from sildenafil-treated animals. The stimulatory effect of NO donor was significantly enhanced by saturating concentrations of hCG in both Leydig cells obtained from control and sildenafil-treated animals. Occurrence of mature steroidogenic acute regulatory protein also increased in sildenafil treated animals in accord with increased cAMP and cGMP production. In summary, inhibition of PDE activity during prolonged sildenafil treatment increased serum testosterone level and Leydig cells' steroidogenic capacity by coordinated stimulatory action on cAMP and cGMP signaling pathway.
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Affiliation(s)
- Silvana A Andric
- Reproductive Endocrinology and Signaling Group, Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, Novi Sad, Serbia
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Kostic TS, Stojkov NJ, Janjic MM, Andric SA. Structural complexity of the testis and PKG I / StAR interaction regulate the Leydig cell adaptive response to repeated immobilization stress. ACTA ACUST UNITED AC 2010; 33:717-29. [DOI: 10.1111/j.1365-2605.2009.01018.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Decreased renal corin expression contributes to sodium retention in proteinuric kidney diseases. Kidney Int 2010; 78:650-9. [PMID: 20613715 DOI: 10.1038/ki.2010.197] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Patients with proteinuric kidney diseases often have symptoms of salt and water retention. It has been hypothesized that dysregulated sodium absorption is due to increased proteolytic cleavage of epithelial sodium channels (ENaCs) and increased Na,K-ATPase expression. Microarray analysis identified a reduction in kidney corin mRNA expression in rat models of puromycin aminonucleoside-induced nephrotic syndrome and acute anti-Thy1 glomerulonephritis (GN). As atrial natriuretic peptide (ANP) resistance is a mechanism accounting for volume retention, we analyzed the renal expression and function of corin; a type II transmembrane serine protease that converts pro-ANP to active ANP. Immunohistochemical analysis found that corin colocalized with ANP. The nephrotic and glomerulonephritic models exhibited concomitant increased pro-ANP and decreased ANP protein levels in the kidney consistent with low amounts of corin. Importantly, kidneys from corin knockout mice had increased amounts of renal β-ENaC and its activators, phosphodiesterase (PDE) 5 and protein kinase G II, when compared to wild-type mice. A similar expression profile was also found in cell culture suggesting the increase in PDE5 and kinase G II could account for the increase in β-ENaC seen in nephrotic syndrome and GN. Thus, we suggest that corin might be involved in the salt retention seen in glomerular diseases.
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Andric SA, Janjic MM, Stojkov NJ, Kostic TS. Testosterone-induced modulation of nitric oxide-cGMP signaling pathway and androgenesis in the rat Leydig cells. Biol Reprod 2010; 83:434-42. [PMID: 20463352 DOI: 10.1095/biolreprod.110.083626] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Testosterone, acting as a systemic and local factor, is one of the major regulatory molecules that initiate and maintain testicular function. In the present study, different experimental approaches were used to evaluate the role of testosterone in regulation of the nitric oxide (NO)-cGMP pathway in Leydig cells derived from normal and hypogonadotropic male rats treated with testosterone for 24 h and 2 wk. Real-time quantitative PCR and Western blot analysis revealed increased inducible NO synthase (NOS2) expression followed by increased NO secretion from Leydig cells ex vivo after continuous treatment with testosterone for 2 wk in vivo. The cGMP-specific phosphodiesterases Pde5, Pde6, and Pde9 were up-regulated, whereas PRKG1 protein was decreased after a 2-wk testosterone treatment. Induction of Nos2 and Pde5 in Leydig cells was blocked by androgen receptor antagonist. In experimental hypogonadotropic hypogonadism, expression of NOS2 was significantly reduced, and treatment with testosterone increased NOS2 expression above control levels. PDE5 protein level was unchanged in hypogonadal rats, whereas treatment of hypogonadal rats with testosterone significantly increased it. In contrast, hypogonadism and testosterone replacement reduced PRKG1 protein in Leydig cells. In vitro treatment with testosterone caused gradually increased Nos2 gene expression followed by increased nitrite and cGMP production by purified Leydig cells. In summary, testosterone up-regulated NO signaling via increased NOS2 expression and contributed to down-regulation of cGMP signaling in Leydig cells. Thus, testosterone-induced modulation of NO-cGMP signaling may serve as a potent autocrine regulator of testicular steroidogenesis.
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Affiliation(s)
- Silvana A Andric
- Reproductive Endocrinology and Signaling Group, Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, Novi Sad, Serbia
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Bibeau K, Battista MC, Houde V, Brochu M. Fetal adrenal gland alterations in a rat model of adverse intrauterine environment. Am J Physiol Regul Integr Comp Physiol 2009; 298:R899-911. [PMID: 19923365 DOI: 10.1152/ajpregu.00238.2009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
By feeding a low-sodium diet to dams over the last third of gestation, we have developed an animal model of intrauterine growth restriction (IUGR). Given that fetal adrenal development and maturation occur during late gestation in rats, the aim of this study was to evaluate the expression of proteins and enzymes involved in steroidogenesis and catecholamine synthesis in adrenal glands from IUGR fetuses. A gene microarray was performed to investigate for alteration in the pathways participating in hormone production. Results show that increased aldosterone serum concentrations in IUGR fetuses were associated with higher mRNA adrenal levels of angiotensin II receptor type 1 (AT(1)R) and cytochrome P450 aldosterone synthase in response to decreased serum sodium content. Conversely, reduced serum corticosterone concentrations in these fetuses appear to result from alterations in gene expression involved in cholesterol metabolism, such as the augmented apolipoprotein E levels, and in steroidogenesis, like the decreased levels of cytochrome P45011beta-hydroxylase. Furthermore, increased AT(2)R expression and the presence of hypoxia and oxidative stress may, in turn, explain the higher adrenal mRNA levels of enzymes involved in catecholamine synthesis. Despite this increase, catecholamine adrenal content was reduced in males and was similar in females compared with sex-matched controls, suggesting higher catecholamine secretion. This could be associated with the induction of genes involved in inflammation-related, acute-phase response in IUGR fetuses. All of these alterations could have long-lasting health effects and may, hence, be implicated in the pathogenesis of increased blood pressure and cardiac hypertrophy observed in IUGR adult animals from this model.
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Affiliation(s)
- Karine Bibeau
- Research Centre, Centre Hospitalier Universitaire Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, QC, Canada H3T 1C5
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Stephenson DT, Coskran TM, Wilhelms MB, Adamowicz WO, O'Donnell MM, Muravnick KB, Menniti FS, Kleiman RJ, Morton D. Immunohistochemical localization of phosphodiesterase 2A in multiple mammalian species. J Histochem Cytochem 2009; 57:933-49. [PMID: 19506089 DOI: 10.1369/jhc.2009.953471] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Phosphodiesterases (PDEs) comprise a family of enzymes that regulate the levels of cyclic nucleotides, key second messengers that mediate a diverse array of functions. PDE2A is an evolutionarily conserved cGMP-stimulated cAMP and cGMP PDE. In the present study, the regional and cellular distribution of PDE2A in tissues of rats, mice, cynomolgus monkeys, dogs, and humans was evaluated by immunohistochemistry. A polyclonal antibody directed to the C-terminal portion of PDE2A specifically detected PDE2A by Western blotting and by immunohistochemistry. The pattern of PDE2A immunoreactivity (ir) was consistent across all species. Western blot analysis demonstrated that PDE2A was most abundant in the brain relative to peripheral tissues. PDE2A ir was heterogeneously distributed within brain and was selectively expressed in particular peripheral tissues. In the brain, prominent immunoreactivity was apparent in components of the limbic system, including the isocortex, hippocampus, amygdala, habenula, basal ganglia, and interpeduncular nucleus. Cytoplasmic PDE2A staining was prominent in several peripheral tissues, including the adrenal zona glomerulosa, neurons of enteric ganglia, endothelial cells in all organs, lymphocytes of spleen and lymph nodes, and pituitary. These studies suggest that PDE2A is evolutionarily conserved across mammalian species and support the hypothesis that the enzyme plays a fundamental role in signal transduction.
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Spießberger B, Bernhard D, Herrmann S, Feil S, Werner C, Luppa PB, Hofmann F. cGMP-dependent protein kinase II and aldosterone secretion. FEBS J 2009; 276:1007-13. [DOI: 10.1111/j.1742-4658.2008.06839.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Abstract
Signalling of cGK (cGMP-dependent protein kinases) are mediated through phosphorylation of specific substrates. Several substrates of cGKI and cGKII were identified meanwhile. Some cGKI substrates are specifically regulated by the cGKIalpha or the cGKIbeta isozyme. In various cells and tissues, different cGK substrates exist that are essential for the regulation of diverse functions comprising tissue contractility, cell motility, cell contact, cellular secretion, cell proliferation, and cell differentiation. On the molecular level, cGKI substrates fulfill various cellular functions regulating e.g. the intracellular calcium and potassium concentration, the calcium sensitivity, and the organisation of the intracellular cytoskeleton. cGKII substrates are involved e.g. in chloride transport, sodium/proton transport and transcriptional regulation. The understanding of cGK signalling and function depends strongly on the identification of further specific substrates. In the last years, diverse approaches ranging from biochemistry to genetic deletion lead to the identification and establishment of several substrates, which raised new insights in the molecular mechanisms of cGK functions and elucidated new cellular cGK functions. However, the analysis of the dynamic signalling of cGK in tissues and cells will be necessary to discover new signalling pathways and substrates.
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Affiliation(s)
- Jens Schlossmann
- Institut für Pharmakologie und Toxikologie, Universität Regensburg, Regensburg, 93055, Germany.
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Hofmann F, Bernhard D, Lukowski R, Weinmeister P. cGMP regulated protein kinases (cGK). Handb Exp Pharmacol 2008:137-62. [PMID: 19089329 DOI: 10.1007/978-3-540-68964-5_8] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
cGMP-dependent protein kinases (cGK) are serine/threonine kinases that are widely distributed in eukaryotes. Two genes--prkg1 and prkg2--code for cGKs, namely cGKI and cGKII. In mammals, two isozymes, cGKIalpha and cGKIbeta, are generated from the prkg1 gene. The cGKI isozymes are prominent in all types of smooth muscle, platelets, and specific neuronal areas such as cerebellar Purkinje cells, hippocampal neurons, and the lateral amygdala. The cGKII prevails in the secretory epithelium of the small intestine, the juxta-glomerular cells, the adrenal cortex, the chondrocytes, and in the nucleus suprachiasmaticus. Both cGKs are major downstream effectors of many, but not all signalling events of the NO/cGMP and the ANP/cGMP pathways. cGKI relaxes smooth muscle tone and prevents platelet aggregation, whereas cGKII inhibits renin secretion, chloride/water secretion in the small intestine, the resetting of the clock during early night, and endochondreal bone growth. cGKs are also modulators of cell growth and many other functions.
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Affiliation(s)
- Franz Hofmann
- Institut für Pharmakologie und Toxikologie der Technischen Universität, Biedersteiner Str. 29, München, 80802, Germany.
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Schreier B, Börner S, Völker K, Gambaryan S, Schäfer SC, Kuhlencordt P, Gassner B, Kuhn M. The heart communicates with the endothelium through the guanylyl cyclase-A receptor: acute handling of intravascular volume in response to volume expansion. Endocrinology 2008; 149:4193-9. [PMID: 18450968 PMCID: PMC2488219 DOI: 10.1210/en.2008-0212] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Atrial natriuretic peptide (ANP) regulates arterial blood pressure and volume. Its guanylyl cyclase-A (GC-A) receptor is expressed in vascular endothelium and mediates increases in cGMP, but the functional relevance is controversial. Notably, mice with endothelial-restricted GC-A deletion [EC GC-A knockout (KO) mice] exhibit significant chronic hypervolemic hypertension. The present study aimed to characterize the endothelial effects of ANP and their relevance for the acute regulation of intravascular fluid volume. We studied the effect of ANP on microvascular permeability to fluorescein isothiocyanate-labeled albumin (BSA) using intravital microscopy on mouse dorsal skinfold chambers. Local superfusion of ANP (100 nm) increased microvascular fluorescein isothiocyanate-BSA extravasation in control but not EC GC-A KO mice. Intravenous infusion of synthetic ANP (500 ng/kg x min) caused immediate increases in hematocrit in control mice, indicating intravascular volume contraction. In EC GC-A KO mice, the hematocrit responses were not only abolished but even reversed. Furthermore, acute vascular volume expansion, which caused release of endogenous cardiac ANP, did not affect resting central venous pressure of control mice but rapidly and significantly increased central venous pressure of EC GC-A KO mice. In cultured lung endothelial cells, ANP provoked cGMP-dependent protein kinase I-mediated phosphorylation of vasodilator-stimulated phosphoprotein. We conclude that ANP, via GC-A, enhances microvascular endothelial macromolecule permeability in vivo. This effect might be mediated by cGMP-dependent protein kinase I-dependent phosphorylation of vasodilator-stimulated phosphoprotein. Modulation of transcapillary protein and fluid transport may represent one of the most important hypovolemic actions of ANP.
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Affiliation(s)
- Barbara Schreier
- Institutes of Physiology, University of Würzburg, D-97070 Würzburg, Germany
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36
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Michael SK, Surks HK, Wang Y, Zhu Y, Blanton R, Jamnongjit M, Aronovitz M, Baur W, Ohtani K, Wilkerson MK, Bonev AD, Nelson MT, Karas RH, Mendelsohn ME. High blood pressure arising from a defect in vascular function. Proc Natl Acad Sci U S A 2008; 105:6702-7. [PMID: 18448676 PMCID: PMC2373316 DOI: 10.1073/pnas.0802128105] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2008] [Indexed: 11/18/2022] Open
Abstract
Hypertension, a major cardiovascular risk factor and cause of mortality worldwide, is thought to arise from primary renal abnormalities. However, the etiology of most cases of hypertension remains unexplained. Vascular tone, an important determinant of blood pressure, is regulated by nitric oxide, which causes vascular relaxation by increasing intracellular cGMP and activating cGMP-dependent protein kinase I (PKGI). Here we show that mice with a selective mutation in the N-terminal protein interaction domain of PKGIalpha display inherited vascular smooth muscle cell abnormalities of contraction, abnormal relaxation of large and resistance blood vessels, and increased systemic blood pressure. Renal function studies and responses to changes in dietary sodium in the PKGIalpha mutant mice are normal. These data reveal that PKGIalpha is required for normal VSMC physiology and support the idea that high blood pressure can arise from a primary abnormality of vascular smooth muscle cell contractile regulation, suggesting a new approach to the diagnosis and therapy of hypertension and cardiovascular diseases.
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Affiliation(s)
- Simon K. Michael
- *Molecular Cardiology Research Institute, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111; and
| | - Howard K. Surks
- *Molecular Cardiology Research Institute, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111; and
| | - Yuepeng Wang
- *Molecular Cardiology Research Institute, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111; and
| | - Yan Zhu
- *Molecular Cardiology Research Institute, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111; and
| | - Robert Blanton
- *Molecular Cardiology Research Institute, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111; and
| | - Michelle Jamnongjit
- *Molecular Cardiology Research Institute, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111; and
| | - Mark Aronovitz
- *Molecular Cardiology Research Institute, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111; and
| | - Wendy Baur
- *Molecular Cardiology Research Institute, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111; and
| | - Kenichi Ohtani
- *Molecular Cardiology Research Institute, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111; and
| | | | - Adrian D. Bonev
- Department of Pharmacology, University of Vermont, Burlington, VT 05405
| | - Mark T. Nelson
- Department of Pharmacology, University of Vermont, Burlington, VT 05405
| | - Richard H. Karas
- *Molecular Cardiology Research Institute, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111; and
| | - Michael E. Mendelsohn
- *Molecular Cardiology Research Institute, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111; and
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Andric SA, Janjic MM, Stojkov NJ, Kostic TS. Protein kinase G-mediated stimulation of basal Leydig cell steroidogenesis. Am J Physiol Endocrinol Metab 2007; 293:E1399-408. [PMID: 17848628 DOI: 10.1152/ajpendo.00482.2007] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The androgen-secreting Leydig cells produce cGMP, but the pathways responsible for generation and actions of this intracellular messenger have been incompletely characterized in these cells. Here, we show the presence of mRNA transcripts for the membrane-bound and soluble guanylyl cyclases (sGC), the cGMP-specific phosphodiesterase 5, and the cGMP-dependent protein kinase I (PKG I) and PKG II in purified rat Leydig cells from adult animals. Stimulation of both guanylyl cyclases and inhibition of phosphodiesterase 5 in vitro were accompanied by elevations in cGMP and androgen production, whereas inhibition of sGC and PKG led to a decrease in steroidogenesis. The stimulatory action of cGMP on steroidogenesis was preserved in cells with inhibited cAMP-dependent protein kinases. Experiments with exogenously added substrates revealed the dependence of cGMP-induced progesterone and androgen synthesis on cholesterol but not on 22-OH cholesterol, pregnenolone, progesterone, and Delta(4)-androstenedione. Treatment with nitric oxide donor increased phosphorylation of the steroidogenic acute regulatory protein (StAR). In contrast, inhibition of sGC and PKG, but not protein kinase A, significantly reduced StAR phosphorylation. These results suggest that cGMP contributes to the control of basal steroidogenesis in Leydig cells through the PKG-dependent modification of the StAR protein.
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Affiliation(s)
- Silvana A Andric
- Laboratory for Reproductive Endocrinology and Signaling, DBE, Faculty of Sciences, University of Novi Sad, Dositeja Obradovica Square 2, 21000, Novi Sad, Serbia
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Gambaryan S, Butt E, Tas P, Smolenski A, Allolio B, Walter U. Regulation of aldosterone production from zona glomerulosa cells by ANG II and cAMP: evidence for PKA-independent activation of CaMK by cAMP. Am J Physiol Endocrinol Metab 2006; 290:E423-33. [PMID: 16219670 DOI: 10.1152/ajpendo.00128.2005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Aldosterone production in zona glomerulosa (ZG) cells of adrenal glands is regulated by various extracellular stimuli (K(+), ANG II, ACTH) that all converge on two major intracellular signaling pathways: an increase in cAMP production and calcium (Ca(2+)) mobilization. However, molecular events downstream of the increase in intracellular cAMP and Ca(2+) content are controversial and far from being completely resolved. Here, we found that Ca(2+)/calmodulin-dependent protein kinases (CaMKs) play a predominant role in the regulation of aldosterone production stimulated by ANG II, ACTH, and cAMP. The specific CaMK inhibitor KN93 strongly reduced ANG II-, ACTH-, and cAMP-stimulated aldosterone production. In in vitro kinase assays and intact cells, we could show that cAMP-induced activation of CaMK, using the adenylate cyclase activator forskolin or the cAMP-analog Sp-5,6-DCI-cBIMPS (cBIMPS), was not mediated by PKA. Activation of the recently identified cAMP target protein Epac (exchange protein directly activated by cAMP) by 8-pCPT-2'-O-Me-cAMP had no effect on CaMK activity and aldosterone production. Furthermore, we provide evidence that cAMP effects in ZG cells do not involve Ca(2+) or MAPK signaling. Our results suggest that ZG cells, in addition to PKA and Epac/Rap proteins, contain other as yet unidentified cAMP mediator(s) involved in regulating CaMK activity and aldosterone secretion.
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Affiliation(s)
- Stepan Gambaryan
- Institute of Clinical Biochemistry and Pathobiochemistry, University of Würzburg, Wurzburg, Germany.
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Sriraman V, Rudd MD, Lohmann SM, Mulders SM, Richards JS. Cyclic Guanosine 5′-Monophosphate-Dependent Protein Kinase II Is Induced by Luteinizing Hormone and Progesterone Receptor-Dependent Mechanisms in Granulosa Cells and Cumulus Oocyte Complexes of Ovulating Follicles. Mol Endocrinol 2006; 20:348-61. [PMID: 16210344 DOI: 10.1210/me.2005-0317] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
AbstractCyclic GMP (cGMP)-dependent protein kinase II (Prkg2, cGK II) was identified as a potential target of the progesterone receptor (Nr3c3) in the mouse ovary based on microarray analyses. To document this further, the expression patterns of cGK II and other components of the cGMP signaling pathway were analyzed during follicular development and ovulation using the pregnant mare serum gonadotropin (PMSG)-human chorionic gonadotropin (hCG)-primed immature mice. Levels of cGK II mRNA were low in ovaries of immature mice, increased 4-fold in response to pregnant mare serum gonadotropin and 5-fold more within 12 h after hCG, the time of ovulation. In situ hybridization localized cGK II mRNA to granulosa cells and cumulus oocyte complexes of periovulatory follicles. In progesterone receptor (PR) null mice, cGK II mRNA was reduced significantly at 12 h after hCG in contrast to heterozygous littermates. In primary granulosa cell cultures, cGK II mRNA was induced by phorbol 12-myristate 13-acetate enhanced by adenoviral expression of PR-A and blocked by RU486 and trilostane. PR-A in the absence of phorbol 12-myristate 13-acetate was insufficient to induce cGK II. Expression of cGK I (Prkg1) was restricted to the residual tissue and not regulated by hormones. Guanylate cyclase-A (Npr1; GC-A) mRNA expression increased 6-fold by 4 h after hCG treatment in contrast to pregnant mare serum gonadotropin alone and was localized to granulosa cells of preovulatory follicles. Collectively, these data show for the first time that cGK II (not cGK I) and GC-A are selectively induced in granulosa cells of preovulatory follicles by LH- and PR-dependent mechanisms, thereby providing a pathway for cGMP function during ovulation.
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Affiliation(s)
- Venkataraman Sriraman
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
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Hofmann F, Feil R, Kleppisch T, Schlossmann J. Function of cGMP-Dependent Protein Kinases as Revealed by Gene Deletion. Physiol Rev 2006; 86:1-23. [PMID: 16371594 DOI: 10.1152/physrev.00015.2005] [Citation(s) in RCA: 327] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Over the past few years, a wealth of biochemical and functional data have been gathered on mammalian cGMP-dependent protein kinases (cGKs). In mammals, three different kinases are encoded by two genes. Mutant and chimeric cGK proteins generated by molecular biology techniques yielded important biochemical knowledge, such as the function of the NH2-terminal domains of cGKI and cGKII, the identity of the cGMP-binding sites of cGKI, and the substrate specificity of the enzymes. Genetic approaches have proven especially useful for the analysis of the biological functions of cGKs. Recently, some of the in vivo targets and mechanisms leading to changes in neuronal adaptation, smooth muscle relaxation and growth, intestinal water secretion, bone growth, renin secretion, and other important functions have been identified. These data show that cGKs are signaling molecules involved in many biological functions.
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Affiliation(s)
- F Hofmann
- Institut für Pharmakologie und Toxicologie, Technische Universität München, Biedersteiner Strasse 29, D-80802 Munich, Germany.
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Kissmehl R, Krüger TP, Treptau T, Froissard M, Plattner H. Multigene family encoding 3',5'-cyclic-GMP-dependent protein kinases in Paramecium tetraurelia cells. EUKARYOTIC CELL 2006; 5:77-91. [PMID: 16400170 PMCID: PMC1360248 DOI: 10.1128/ec.5.1.77-91.2006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Accepted: 11/01/2005] [Indexed: 01/28/2023]
Abstract
In the ciliate Paramecium tetraurelia, 3',5'-cyclic GMP (cGMP) is one of the second messengers involved in several signal transduction pathways. The enzymes for its production and degradation are well established for these cells, whereas less is known about the potential effector proteins. On the basis of a current Paramecium genome project, we have identified a multigene family with at least 35 members, all of which encode cGMP-dependent protein kinases (PKGs). They can be classified into 16 subfamilies with several members each. Two of the genes, PKG1-1 and PKG2-1, were analyzed in more detail after molecular cloning. They encode monomeric enzymes of 770 and 819 amino acids, respectively, whose overall domain organization resembles that in higher eukaryotes. The enzymes contain a regulatory domain of two tandem cyclic nucleotide-binding sites flanked by an amino-terminal region for intracellular localization and a catalytic domain with highly conserved regions for ATP binding and catalysis. However, some Paramecium PKGs show a different structure. In Western blots, PKGs are detected both as cytosolic and as structure-bound forms. Immunofluorescence labeling shows enrichment in the cell cortex, notably around the dense-core secretory vesicles (trichocysts), as well as in cilia. Immunogold electron microscopy analysis reveals consistent labeling of ciliary membranes, of the membrane complex composed of cell membrane and cortical Ca2+ stores, and of regions adjacent to ciliary basal bodies, trichocysts, and trafficking vesicles. Since PKGs (re)phosphorylate the exocytosis-sensitive phosphoprotein pp63/pf upon stimulation, the role of PKGs during stimulated exocytosis is discussed, in addition to a role in ciliary beat regulation.
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Affiliation(s)
- Roland Kissmehl
- Department of Biology, University of Konstanz, P.O. Box 5560, 78457 Konstanz, Germany.
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Abstract
Cyclic guanosine-3', 5'-monophosphate (cGMP)-dependent protein kinases (cGKs) are key enzymes of nitric oxide-cGMP and natriuretic peptide signalling cascades. These kinases mediate most of the effects of cGMP-elevating drugs, such as nitrates and phosphodiesterase inhibitors. cGKs modulate smooth muscle relaxation (e.g. the vasculature, gastrointestinal tract, bladder and penile), platelet aggregation, renin release, intestinal secretion, learning and memory. Furthermore, several cGK substrates have been identified. Isozyme-specific inhibitors and activators of cGK and its downstream substrates might act more specifically than upstream signalling activators, such as organic nitrates and phosphodiesterase inhibitors.
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Affiliation(s)
- Jens Schlossmann
- Institut für Pharmakologie und Toxikologie der Technischen Universität München, Biedersteiner Strasse 29, 80802 München, Germany.
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Nikolaev VO, Gambaryan S, Engelhardt S, Walter U, Lohse MJ. Real-time monitoring of the PDE2 activity of live cells: hormone-stimulated cAMP hydrolysis is faster than hormone-stimulated cAMP synthesis. J Biol Chem 2004; 280:1716-9. [PMID: 15557342 DOI: 10.1074/jbc.c400505200] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclic nucleotide phosphodiesterases (PDEs) are the enzymes that catalyze the hydrolysis of cAMP and cGMP, thereby restricting the activity of these second messengers in cells. A unique ability to shape gradients of cyclic nucleotides and compartmentalize their signaling implies a high potency and a rapid action of PDEs. However, it has not been demonstrated how fast PDEs can hydrolyze cAMP in a living system. Here we perform a real-time monitoring of PDE2 activity in aldosterone-producing adrenal cells using a recently developed genetically encoded, fluorescent cAMP sensor, which reveals enormously rapid kinetics of cAMP degradation. Activation of PDE2 results in a rapid decrease of intracellular cAMP from high micromolar to the sub-micromolar range within a few seconds. Moreover, the kinetics of atrial natriuretic peptide-stimulated PDE2 activity (measured as decline of cAMP) are much faster than the speed of ACTH and isoprenaline-induced cAMP-synthesis (measured as cAMP accumulation) in the cells, revealing high catalytic activity and fast action of PDEs in regulating cAMP signaling in a physiological system.
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Affiliation(s)
- Viacheslav O Nikolaev
- Institute of Pharmacology and Toxicology, University of Würzburg, Versbacher Strasse 9, D-97078 Würzburg, Germany
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Affiliation(s)
- Franz Hofmann
- Institut für Pharmakologie und Toxikologie, Technische Universität München, Biedersteiner Strasse 29, D-80802 München, Germany
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Golombek DA, Agostino PV, Plano SA, Ferreyra GA. Signaling in the mammalian circadian clock: the NO/cGMP pathway. Neurochem Int 2004; 45:929-36. [PMID: 15312987 DOI: 10.1016/j.neuint.2004.03.023] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mammalian circadian rhythms are generated by a hypothalamic suprachiasmatic nuclei (SCN) clock. Light pulses synchronize body rhythms by inducing phase delays during the early night and phase advances during the late night. Phosphorylation events are known to be involved in circadian phase shifting, both for delays and advances. Pharmacological inhibition of the cGMP-dependent kinase (cGK) or Ca2+/calmodulin-dependent kinase (CaMK), or of neuronal nitric oxide synthase (nNOS) blocks the circadian responses to light in vivo. Light pulses administered during the subjective night, but not during the day, induce rapid phosphorylation of both p-CAMKII and p-nNOS (specifically phosphorylated by CaMKII). CaMKII inhibitors block light-induced nNOS activity and phosphorylation, suggesting a direct pathway between both enzymes. Furthermore, SCN cGMP exhibits diurnal and circadian rhythms with maximal values during the day or subjective day. This variation of cGMP levels appears to be related to temporal changes in phosphodiesterase (PDE) activity and not to guanylyl cyclase (GC) activity. Light pulses increase SCN cGMP levels at circadian time (CT) 18 (when light causes phase advances of rhythms) but not at CT 14 (the time for light-induced phase delays). cGK II is expressed in the hamster SCN and also exhibits circadian changes in its levels, peaking during the day. Light pulses increase cGK activity at CT 18 but not at CT 14. In addition, cGK and GC inhibition by KT-5823 and ODQ significantly attenuated light-induced phase shifts at CT 18. This inhibition did not change c-Fos expression SCN but affected the expression of the clock gene per in the SCN. These results suggest a signal transduction pathway responsible for light-induced phase advances of the circadian clock which could be summarized as follows: Glu-Ca2+-CaMKII-nNOS-GC-cGMP-cGK-->-->clock genes. This pathway offers a signaling window that allows peering into the circadian clock machinery in order to decipher its temporal cogs and wheels.
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Affiliation(s)
- Diego A Golombek
- Laboratory of Chronobiology, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Roque Saenz Peña 180, Bernal (1876), Buenos Aires, Argentina.
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46
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Fleury A, Mathieu AP, Ducharme L, Hales DB, LeHoux JG. Phosphorylation and function of the hamster adrenal steroidogenic acute regulatory protein (StAR). J Steroid Biochem Mol Biol 2004; 91:259-71. [PMID: 15336703 DOI: 10.1016/j.jsbmb.2004.04.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2003] [Accepted: 04/30/2004] [Indexed: 10/26/2022]
Abstract
In order to study the effect of phosphorylation on the function of the steroidogenic acute regulatory protein (StAR), 10 putative phosphorylation sites were mutated in the hamster StAR. In pcDNA3.1-StAR transfected COS-1 cells, decreases in basal activity were found for the mutants S55A, S185A and S194A. Substitution of S185 by D or E to mimic phosphorylation resulted in decreased activity for all mutants; we concluded that S185 was not a phosphorylation site and we hypothesized that mutations on S185 created StAR conformational changes resulting in a decrease in its binding affinity for cholesterol. In contrast, the mutation S194D resulted in an increase in StAR activity. We have calculated the relative rate of pregnenolone formation (App. V(max)) in transfected COS-1 cells with wild type (WT) and mutant StAR-pcDNA3.1 under control and (Bu)(2)-cAMP stimulation. The App. V(max) values refer to the rate of cholesterol transported and metabolized by the cytochrome P450scc enzyme present in the inner mitochondrial membrane. The App. V(max) was 1.61 +/- 0.28 for control (Ctr) WT StAR and this value was significantly increased to 4.72 +/- 0.09 for (Bu)(2)-cAMP stimulated preparations. App. V(max) of 5.53 (Ctr) and 4.82 ((Bu)(2)-cAMP) found for S194D StAR preparations were similar to that of the WT StAR stimulated preparations. At equal StAR quantity, an anti-phospho-(S/T) PKA substrate antibody revealed four times more phospho-(S/T) in (Bu)(2)-cAMP than in control preparations. The intensity of phosphorylated bands was decreased for the S55A, S56A and S194A mutants and it was completely abolished for the S55A/S56A/S194A mutant. StAR activity of control and stimulated preparations were diminished by 73 and 72% for the mutant S194A compared to 77 and 83% for the mutant S55A/S56A/S194A. The remaining activity appears to be independent of phosphorylation at PKA sites and could be due to the intrinsic activity of non-phosphorylated StAR or to an artefact due to the pharmacological quantity of StAR expressed in COS-1. In conclusion we have shown that (Bu)(2)-cAMP provokes an augmentation of both the quantity and activity of StAR, and that an enhancement in StAR phosphorylation increases its activity. The increased quantity of StAR upon (Bu)(2)-cAMP stimulation could be due to an augmentation of its mRNA or protein synthesis stability, or both; this is yet to be determined.
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Affiliation(s)
- Alain Fleury
- Department of Biochemistry, Faculty of Medicine, University of Sherbrooke, Sherbrooke, Quebec, Canada J1H 5N4
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