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Abstract
The 3',5'-cyclic guanosine monophosphate (cGMP)-dependent protein kinase type I (cGKI aka PKGI) is a major cardiac effector acting downstream of nitric oxide (NO)-sensitive soluble guanylyl cyclase and natriuretic peptides (NPs), which signal through transmembrane guanylyl cyclases. Consistent with the wide distribution of the cGMP-generating guanylyl cyclases, cGKI, which usually elicits its cellular effects by direct phosphorylation of its targets, is present in multiple cardiac cell types including cardiomyocytes (CMs). Although numerous targets of cGMP/cGKI in heart were identified in the past, neither their exact patho-/physiological functions nor cell-type specific roles are clear. Herein, we inform about the current knowledge on the signal transduction downstream of CM cGKI. We believe that better insights into the specific actions of cGMP and cGKI in these cells will help to guide future studies in the search for predictive biomarkers for the response to pharmacological cGMP pathway modulation. In addition, targets downstream of cGMP/cGKI may be exploited for refined and optimized diagnostic and therapeutic strategies in different types of heart disease and their causes. Importantly, key functions of these proteins and particularly sites of regulatory phosphorylation by cGKI should, at least in principle, remain intact, although upstream signaling through the second messenger cGMP is impaired or dysregulated in a stressed or diseased heart state.
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2
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Liu G, Shea CM, Jones JE, Price GM, Warren W, Lonie E, Yan S, Currie MG, Profy AT, Masferrer JL, Zimmer DP. Praliciguat inhibits progression of diabetic nephropathy in ZSF1 rats and suppresses inflammation and apoptosis in human renal proximal tubular cells. Am J Physiol Renal Physiol 2020; 319:F697-F711. [PMID: 32865013 DOI: 10.1152/ajprenal.00003.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Praliciguat, a clinical-stage soluble guanylate cyclase (sGC) stimulator, increases cGMP via the nitric oxide-sGC pathway. Praliciguat has been shown to be renoprotective in rodent models of hypertensive nephropathy and renal fibrosis. In the present study, praliciguat alone and in combination with enalapril attenuated proteinuria in the obese ZSF1 rat model of diabetic nephropathy. Praliciguat monotherapy did not affect hemodynamics. In contrast, enalapril monotherapy lowered blood pressure but did not attenuate proteinuria. Renal expression of genes in pathways involved in inflammation, fibrosis, oxidative stress, and kidney injury was lower in praliciguat-treated obese ZSF1 rats than in obese control rats; fasting glucose and cholesterol were also lower with praliciguat treatment. To gain insight into how tubular mechanisms might contribute to its pharmacological effects on the kidneys, we studied the effects of praliciguat on pathological processes and signaling pathways in cultured human primary renal proximal tubular epithelial cells (RPTCs). Praliciguat inhibited the expression of proinflammatory cytokines and secretion of monocyte chemoattractant protein-1 in tumor necrosis factor-α-challenged RPTCs. Praliciguat treatment also attenuated transforming growth factor-β-mediated apoptosis, changes to a mesenchyme-like cellular phenotype, and phosphorylation of SMAD3 in RPTCs. In conclusion, praliciguat improved proteinuria in the ZSF1 rat model of diabetic nephropathy, and its actions in human RPTCs suggest that tubular effects may contribute to its renal benefits, building upon strong evidence for the role of cGMP signaling in renal health.
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Affiliation(s)
- Guang Liu
- Department of Pharmacology, Cyclerion Therapeutics, Cambridge, Massachusetts
| | - Courtney M Shea
- Department of Pharmacology, Cyclerion Therapeutics, Cambridge, Massachusetts
| | - Juli E Jones
- Department of Pharmacology, Cyclerion Therapeutics, Cambridge, Massachusetts
| | - Gavrielle M Price
- Department of Medical Writing, Cyclerion Therapeutics, Cambridge, Massachusetts
| | - William Warren
- Department of Analytical Pharmacology, Ironwood Pharmaceuticals, Cambridge, Massachusetts
| | - Elisabeth Lonie
- Department of Analytical Pharmacology, Ironwood Pharmaceuticals, Cambridge, Massachusetts
| | - Shu Yan
- Department of Discovery Informatics, Cyclerion Therapeutics, Cambridge, Massachusetts
| | - Mark G Currie
- Department of Research Management, Cyclerion Therapeutics, Cambridge, Massachusetts
| | - Albert T Profy
- Department of Development Management, Cyclerion Therapeutics, Cambridge, Massachusetts
| | - Jaime L Masferrer
- Department of Pharmacology, Cyclerion Therapeutics, Cambridge, Massachusetts
| | - Daniel P Zimmer
- Department of Pharmacology, Cyclerion Therapeutics, Cambridge, Massachusetts
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Vargas-Castillo A, Tobon-Cornejo S, Del Valle-Mondragon L, Torre-Villalvazo I, Schcolnik-Cabrera A, Guevara-Cruz M, Pichardo-Ontiveros E, Fuentes-Romero R, Bader M, Alenina N, Vidal-Puig A, Hong E, Torres N, Tovar AR. Angiotensin-(1-7) induces beige fat thermogenesis through the Mas receptor. Metabolism 2020; 103:154048. [PMID: 31843339 DOI: 10.1016/j.metabol.2019.154048] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 12/06/2019] [Accepted: 12/11/2019] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Angiotensin-(1-7) [Ang-(1-7)], a component of the renin angiotensin system, is a vasodilator that exerts its effects primarily through the Mas receptor. The discovery of the Mas receptor in white adipose tissue (WAT) suggests an additional role for this peptide. The aim of the present study was to assess whether Ang-(1-7) can induce the expression of thermogenic genes in white adipose tissue and increase mitochondrial respiration in adipocytes. MATERIALS/METHODS Stromal Vascular fraction (SVF)-derived from mice adipose tissue was stimulated for one week with Ang-(1-7), then expression of beige markers and mitochondrial respiration were assessed. Mas+/+ and Mas-/- mice fed a control diet or a high fat-sucrose diet (HFSD) were exposed to a short or long term infusion of Ang-(1-7) and body weight, body fat, energy expenditure, cold resistance and expression of beige markers were assessed. Also, transgenic rats overexpressing Ang-(1-7) were fed with a control diet or a high fat-sucrose diet and the same parameters were assessed. Ang-(1-7) circulating levels from human subjects with different body mass index (BMI) or age were measured. RESULTS Incubation of adipocytes derived from SVF with Ang-(1-7) increased the expression of beige markers. Infusion of Ang-(1-7) into lean and obese Mas+/+mice also induced the expression of Ucp1 and some beige markers, an effect not observed in Mas-/- mice. Mas-/- mice had increased body weight gain and decreased cold resistance, whereas rats overexpressing Ang-(1-7) showed the opposite effects. Overexpressing rats exposed to cold developed new thermogenic WAT in the anterior interscapular area. Finally, in human subjects the higher the BMI, low circulating concentration of Ang-(1-7) levels were detected. Similarly, the circulating levels of Ang-(1-7) peptide were reduced with age. CONCLUSION These data indicate that Ang-(1-7) stimulates beige markers and thermogenesis via the Mas receptor, and this evidence suggests a potential therapeutic use to induce thermogenesis of WAT, particularly in obese subjects that have reduced circulating concentration of Ang-(1-7).
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MESH Headings
- Adipose Tissue, Beige/drug effects
- Adipose Tissue, Beige/metabolism
- Adipose Tissue, White/drug effects
- Adipose Tissue, White/metabolism
- Adult
- Angiotensin I/pharmacology
- Animals
- Cell Respiration/drug effects
- Cell Respiration/genetics
- Cells, Cultured
- Energy Metabolism/genetics
- Female
- Humans
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Middle Aged
- Obesity/genetics
- Obesity/metabolism
- Obesity/pathology
- Peptide Fragments/pharmacology
- Proto-Oncogene Mas
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/physiology
- Rats
- Rats, Transgenic
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/physiology
- Thermogenesis/drug effects
- Thermogenesis/genetics
- Young Adult
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Affiliation(s)
- Ariana Vargas-Castillo
- Departmento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Ciudad de México 14080, Mexico; Deparmento de Farmacobiología, Centro de Investigación y de Estudios Avanzados Sede Sur, Ciudad de México 14330, Mexico
| | - Sandra Tobon-Cornejo
- Departmento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Ciudad de México 14080, Mexico
| | | | - Ivan Torre-Villalvazo
- Departmento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Ciudad de México 14080, Mexico
| | - Alejandro Schcolnik-Cabrera
- Departmento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Ciudad de México 14080, Mexico
| | - Martha Guevara-Cruz
- Departmento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Ciudad de México 14080, Mexico
| | - Edgar Pichardo-Ontiveros
- Departmento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Ciudad de México 14080, Mexico
| | - Rebeca Fuentes-Romero
- Departmento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Ciudad de México 14080, Mexico
| | - Michael Bader
- Max Delbrück Center for Molecular Medicine, Berlin 13092, Germany; Charité University Medicine Berlin, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Berlin, Germany; Institute for Biology, University of Lübeck, Germany
| | - Natalia Alenina
- Max Delbrück Center for Molecular Medicine, Berlin 13092, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Berlin, Germany
| | - Antonio Vidal-Puig
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, MDU MRC, Cambridge, United Kingdom
| | - Enrique Hong
- Deparmento de Farmacobiología, Centro de Investigación y de Estudios Avanzados Sede Sur, Ciudad de México 14330, Mexico
| | - Nimbe Torres
- Departmento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Ciudad de México 14080, Mexico
| | - Armando R Tovar
- Departmento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Ciudad de México 14080, Mexico.
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Frigolet ME, Thomas G, Beard K, Lu H, Liu L, Fantus IG. The bradykinin-cGMP-PKG pathway augments insulin sensitivity via upregulation of MAPK phosphatase-5 and inhibition of JNK. Am J Physiol Endocrinol Metab 2017; 313:E321-E334. [PMID: 28679626 DOI: 10.1152/ajpendo.00298.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 05/25/2017] [Accepted: 05/30/2017] [Indexed: 01/13/2023]
Abstract
Bradykinin (BK) promotes insulin sensitivity and glucose uptake in adipocytes and other cell types. We demonstrated that in rat adipocytes BK enhances insulin-stimulated glucose transport via endothelial nitric oxide synthase, nitric oxide (NO) generation, and decreased activity of the mitogen-activated protein kinase (MAPK) JNK (c-Jun NH2-terminal kinase). In endothelial cells, NO increases soluble guanylate cyclase (sGC) activity, which, in turn, activates protein kinase G (PKG) by increasing cGMP levels. In this study, we investigated whether BK acts via the sGC-cGMP-PKG pathway to inhibit the negative effects of JNK on insulin signaling and glucose uptake in rat adipocytes. BK augmented cGMP concentrations. The BK-induced enhancement of insulin-stimulated glucose uptake was mimicked by the sGC activator YC-1 and a cell-permeable cGMP analog, CPT-cGMP, and inhibited by the sGC inhibitor ODQ and the PKG inhibitor KT 5823. Transfection of dominant-negative PKG reduced the BK augmentation of insulin-induced Akt phosphorylation. The activation of JNK and ERK1/2 by insulin was attenuated by BK, which was mediated by the sGC-cGMP-PKG pathway. Whereas insulin-stimulated phosphorylation of upstream activators of JNK and ERK, i.e., MKK4 and MEK1/2, was unaffected, BK augmented insulin-mediated induction of MKP-5 mRNA and protein levels. Furthermore, zaprinast, a phosphodiesterase inhibitor, enhanced cGMP and MKP-5 and prolonged the action of BK. These data indicate that BK enhances insulin action by inhibition of negative feedback by JNK and ERK via upregulation of MKP-5, mediated by the sGC-cGMP-PKG signaling pathway.
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Affiliation(s)
- María E Frigolet
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
- Banting and Best Diabetes Centre, Toronto, Ontario, Canada; and
| | - Garry Thomas
- Department of Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada
- Banting and Best Diabetes Centre, Toronto, Ontario, Canada; and
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Kristin Beard
- Department of Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada
- Banting and Best Diabetes Centre, Toronto, Ontario, Canada; and
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Huogen Lu
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Lijiang Liu
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
| | - I George Fantus
- Department of Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada;
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
- Banting and Best Diabetes Centre, Toronto, Ontario, Canada; and
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
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Thyagarajan B, Foster MT. Beiging of white adipose tissue as a therapeutic strategy for weight loss in humans. Horm Mol Biol Clin Investig 2017; 31:/j/hmbci.ahead-of-print/hmbci-2017-0016/hmbci-2017-0016.xml. [PMID: 28672737 DOI: 10.1515/hmbci-2017-0016] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 04/18/2017] [Indexed: 12/16/2022]
Abstract
An imbalance between energy intake and expenditure leads to obesity. Adiposity associated with obesity progressively causes inflammation, type 2 diabetes, hypertension, hyperlipidemia and cardiovascular disease. Excessive dietary intake of fat results in its accumulation and storage in the white adipose tissue (WAT), whereas energy expenditure by fat utilization and oxidation predominately occurs in the brown adipose tissue (BAT). Recently, the presence of a third type of fat, referred to as beige or brite (brown in white), has been recognized in certain kinds of WAT depots. It has been suggested that WAT can undergo the process of browning in response to stimuli that induce and enhance the expression of thermogenes characteristic of those typically associated with brown fat. The resultant beige or brite cells enhance energy expenditure by reducing lipids stored within adipose tissue. This has created significant excitement towards the development of a promising strategy to induce browning/beiging in WAT to combat the growing epidemic of obesity. This review systematically describes differential locations and functions of WAT and BAT, mechanisms of beiging of WAT and a concise analysis of drug molecules and natural products that activate the browning phenomenon in vitro and in vivo. This review also discusses potential approaches for targeting WAT with compounds for site-specific beiging induction. Overall, there are numerous mechanisms that govern browning of WAT. There are a variety of newly identified targets whereby potential molecules can promote beiging of WAT and thereby combat obesity.
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Illison J, Tian L, McClafferty H, Werno M, Chamberlain LH, Leiss V, Sassmann A, Offermanns S, Ruth P, Shipston MJ, Lukowski R. Obesogenic and Diabetogenic Effects of High-Calorie Nutrition Require Adipocyte BK Channels. Diabetes 2016; 65:3621-3635. [PMID: 27605626 DOI: 10.2337/db16-0245] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 08/16/2016] [Indexed: 11/13/2022]
Abstract
Elevated adipose tissue expression of the Ca2+- and voltage-activated K+ (BK) channel was identified in morbidly obese men carrying a BK gene variant, supporting the hypothesis that K+ channels affect the metabolic responses of fat cells to nutrients. To establish the role of endogenous BKs in fat cell maturation, storage of excess dietary fat, and body weight (BW) gain, we studied a gene-targeted mouse model with global ablation of the BK channel (BKL1/L1) and adipocyte-specific BK-deficient (adipoqBKL1/L2) mice. Global BK deficiency afforded protection from BW gain and excessive fat accumulation induced by a high-fat diet (HFD). Expansion of white adipose tissue-derived epididymal BKL1/L1 preadipocytes and their differentiation to lipid-filled mature adipocytes in vitro, however, were improved. Moreover, BW gain and total fat masses of usually superobese ob/ob mice were significantly attenuated in the absence of BK, together supporting a central or peripheral role for BKs in the regulatory system that controls adipose tissue and weight. Accordingly, HFD-fed adipoqBKL1/L2 mutant mice presented with a reduced total BW and overall body fat mass, smaller adipocytes, and reduced leptin levels. Protection from pathological weight gain in the absence of adipocyte BKs was beneficial for glucose handling and related to an increase in body core temperature as a result of higher levels of uncoupling protein 1 and a low abundance of the proinflammatory interleukin-6, a common risk factor for diabetes and metabolic abnormalities. This suggests that adipocyte BK activity is at least partially responsible for excessive BW gain under high-calorie conditions, suggesting that BK channels are promising drug targets for pharmacotherapy of metabolic disorders and obesity.
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Affiliation(s)
- Julia Illison
- Pharmakologie, Toxikologie und Klinische Pharmazie, Institut für Pharmazie, Tübingen, Germany
| | - Lijun Tian
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, U.K
| | - Heather McClafferty
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, U.K
| | - Martin Werno
- Strathclyde Institute of Pharmacy and Biomedical Sciences, Strathclyde University, Glasgow, U.K
| | - Luke H Chamberlain
- Strathclyde Institute of Pharmacy and Biomedical Sciences, Strathclyde University, Glasgow, U.K
| | - Veronika Leiss
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, University Hospital Tübingen, Tübingen, Germany
| | - Antonia Sassmann
- Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Stefan Offermanns
- Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Peter Ruth
- Pharmakologie, Toxikologie und Klinische Pharmazie, Institut für Pharmazie, Tübingen, Germany
| | - Michael J Shipston
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, U.K
| | - Robert Lukowski
- Pharmakologie, Toxikologie und Klinische Pharmazie, Institut für Pharmazie, Tübingen, Germany
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7
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Abstract
The second messenger cyclic guanosine monophosphate (cGMP) is a key mediator in physiological processes such as vascular tone, and its essential involvement in pathways regulating metabolism has been recognized in recent years. Here, we focus on the fundamental role of cGMP in brown adipose tissue (BAT) differentiation and function. In contrast to white adipose tissue (WAT), which stores energy in the form of lipids, BAT consumes energy stored in lipids to generate heat. This so-called non-shivering thermogenesis takes place in BAT mitochondria, which express the specific uncoupling protein 1 (UCP1). The energy combusting properties of BAT render it a promising target in antiobesity strategies in which BAT could burn the surplus energy that has accumulated in obese and overweight individuals. cGMP is generated by guanylyl cyclases upon activation by nitric oxide or natriuretic peptides. It affects several downstream molecules including cGMP-receptor proteins such as cGMP-dependent protein kinase and is degraded by phosphodiesterases. The cGMP pathway contains several signaling molecules that can increase cGMP signaling, resulting in activation and recruitment of brown adipocytes, and hence can enhance the energy combusting features of BAT. In this review we highlight recent results showing the physiological significance of cGMP signaling in BAT, as well as pharmacological options targeting cGMP signaling that bear a high potential to become BAT-centered therapies for the treatment of obesity.
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8
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Attenuated atrial natriuretic peptide-mediated lipolysis in subcutaneous adipocytes of obese type 2 diabetic men. Clin Sci (Lond) 2016; 130:1105-14. [DOI: 10.1042/cs20160220] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 04/01/2016] [Indexed: 11/17/2022]
Abstract
Subjects with obesity seem to display a suboptimal exercise response, which might be due to hormonal disturbances. In the present study, we show the adipose tissue of obese subjects to be less sensitive to atrial natriuretic peptide, a cardiac hormone important during exercise.
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Johlfs MG, Gorjala P, Urasaki Y, Le TT, Fiscus RR. Capillary Isoelectric Focusing Immunoassay for Fat Cell Differentiation Proteomics. PLoS One 2015; 10:e0132105. [PMID: 26132171 PMCID: PMC4489199 DOI: 10.1371/journal.pone.0132105] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 06/10/2015] [Indexed: 01/09/2023] Open
Abstract
Profiling cellular proteome is critical to understanding signal integration during cell fate determination. In this study, the capability of capillary isoelectric focusing (cIEF) immunoassays to detect post-translational modifications (PTM) of protein isoforms is demonstrated. cIEF immunoassays exhibit protein detection sensitivity at up to 5 orders of magnitude higher than traditional methods. This detection ultra-sensitivity permits proteomic profiling of several nanograms of tissue samples. cIEF immunoassays are employed to simultaneously profile three protein kinases during fat cell differentiation: cGMP-dependent protein kinase type I (PKG-I) of the nitric oxide (NO) signaling pathway, protein kinase B (Akt) of the insulin signaling pathway, and extracellular signal-regulated kinase (ERK) of the mitogen-activated protein kinase (MAPK) signaling pathway. Interestingly, a switch in the expression level of PKG- isoforms is observed during fat cell differentiation. While both PKG-Iα and PKG-Iβ isoforms are present in preadipocytes, only PKG-Iβ isoform is expressed in adipocytes. On the other hand, the phosphorylation level increases for Akt while decreases for ERK1 and ERK2 following the maturation of preadipocytes into adipocytes. Taken together, cIEF immunoassay provides a highly sensitive means to study fat cell differentiation proteomics. cIEF immunoassay should be a powerful proteomics tool to study complex protein signal integration in biological systems.
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Affiliation(s)
- Mary G. Johlfs
- Department of Biomedical Sciences, Center for Diabetes and Obesity Research, College of Medicine, Roseman University of Health Sciences, 10530 Discovery Drive, Las Vegas, Nevada, 89135, United States of America
| | - Priyatham Gorjala
- Department of Biomedical Sciences, Center for Diabetes and Obesity Research, College of Medicine, Roseman University of Health Sciences, 10530 Discovery Drive, Las Vegas, Nevada, 89135, United States of America
| | - Yasuyo Urasaki
- Department of Biomedical Sciences, Center for Diabetes and Obesity Research, College of Medicine, Roseman University of Health Sciences, 10530 Discovery Drive, Las Vegas, Nevada, 89135, United States of America
| | - Thuc T. Le
- Department of Biomedical Sciences, Center for Diabetes and Obesity Research, College of Medicine, Roseman University of Health Sciences, 10530 Discovery Drive, Las Vegas, Nevada, 89135, United States of America
- * E-mail: (TTL); (RRF)
| | - Ronald R. Fiscus
- Department of Biomedical Sciences, Center for Diabetes and Obesity Research, College of Medicine, Roseman University of Health Sciences, 10530 Discovery Drive, Las Vegas, Nevada, 89135, United States of America
- * E-mail: (TTL); (RRF)
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Brennenstuhl C, Tanimoto N, Burkard M, Wagner R, Bolz S, Trifunovic D, Kabagema-Bilan C, Paquet-Durand F, Beck SC, Huber G, Seeliger MW, Ruth P, Wissinger B, Lukowski R. Targeted ablation of the Pde6h gene in mice reveals cross-species differences in cone and rod phototransduction protein isoform inventory. J Biol Chem 2015; 290:10242-55. [PMID: 25739440 DOI: 10.1074/jbc.m114.611921] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Indexed: 11/06/2022] Open
Abstract
Phosphodiesterase-6 (PDE6) is a multisubunit enzyme that plays a key role in the visual transduction cascade in rod and cone photoreceptors. Each type of photoreceptor utilizes discrete catalytic and inhibitory PDE6 subunits to fulfill its physiological tasks, i.e. the degradation of cyclic guanosine-3',5'-monophosphate at specifically tuned rates and kinetics. Recently, the human PDE6H gene was identified as a novel locus for autosomal recessive (incomplete) color blindness. However, the three different classes of cones were not affected to the same extent. Short wave cone function was more preserved than middle and long wave cone function indicating that some basic regulation of the PDE6 multisubunit enzyme was maintained albeit by a unknown mechanism. To study normal and disease-related functions of cone Pde6h in vivo, we generated Pde6h knock-out (Pde6h(-/-)) mice. Expression of PDE6H in murine eyes was restricted to both outer segments and synaptic terminals of short and long/middle cone photoreceptors, whereas Pde6h(-/-) retinae remained PDE6H-negative. Combined in vivo assessment of retinal morphology with histomorphological analyses revealed a normal overall integrity of the retinal organization and an unaltered distribution of the different cone photoreceptor subtypes upon Pde6h ablation. In contrast to human patients, our electroretinographic examinations of Pde6h(-/-) mice suggest no defects in cone/rod-driven retinal signaling and therefore preserved visual functions. To this end, we were able to demonstrate the presence of rod PDE6G in cones indicating functional substitution of PDE6. The disparities between human and murine phenotypes caused by mutant Pde6h/PDE6H suggest species-to-species differences in the vulnerability of biochemical and neurosensory pathways of the visual signal transduction system.
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Affiliation(s)
- Christina Brennenstuhl
- From the Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy
| | | | - Markus Burkard
- From the Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy
| | - Rebecca Wagner
- From the Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy
| | | | | | - Clement Kabagema-Bilan
- From the Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy
| | | | | | | | | | - Peter Ruth
- From the Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy
| | - Bernd Wissinger
- the Molecular Genetics Laboratory, Centre for Ophthalmology, University of Tuebingen, 72076 Tuebingen, Germany
| | - Robert Lukowski
- From the Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy,
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