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Svart M, Rittig N, Pedersen SB, Jessen N, Møller N. Oral 3-hydroxybutyrate ingestion decreases endogenous glucose production, lipolysis, and hormone-sensitive lipase phosphorylation in adipose tissue in men: a human randomized, controlled, crossover trial. Diabet Med 2021; 38:e14385. [PMID: 32794582 DOI: 10.1111/dme.14385] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 07/10/2020] [Accepted: 07/15/2020] [Indexed: 01/25/2023]
Abstract
AIMS To test whether oral administration of D/L-3-hydroxybutyrate as a sodium salt inhibits lipolysis and intracellular lipid signalling, in particular, hormone-sensitive lipase, and whether D/L-3-hydroxybutyrate alters endogenous glucose production. METHODS We studied six young men in a randomized, controlled, crossover study after ingestion of Na-D/L-3-hydroxybutyrate (hyperketotic condition) or saline (placebo control). We quantified lipolysis and endogenous glucose production using [9,10-3 H]-palmitate and [3-3H]glucose tracers, and adipose tissue biopsies were collected to investigate key lipolytic enzymes. RESULTS After ingestion, D/L-3-hydroxybutyrate increased by more than 2.5 mmol/l, free fatty acid concentrations decreased by >70%, and palmitate rate of appearance was halved. Protein kinase A phosphorylation of perilipin was reduced and hormone-sensitive lipase 660 phosphorylation in adipose tissue biopsies was 70-80% decreased in the hyperketotic condition and unchanged in the control. Compared to the control, endogenous glucose production was reduced by close to 20% (P<0.05) after 3-hydroxybutyrate ingestion. CONCLUSION We conclude that oral D/L-Na-3-hydroxybutyrate increases D/L-3-hydroxybutyrate concentrations within half an hour, decreases free fatty acid concentrations, lowers lipolysis and endogenous glucose production, and dephosphorylates hormone-sensitive lipase. Collectively these phenomena may be viewed as an orchestrated feedback loop, controlling endogenous glucose production, lipolysis and ketogenesis. Such effects would be beneficial in insulin-resistant states. (www.clinicaltrials.gov ID number: NCT02917252).
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Affiliation(s)
- M Svart
- Departments of Endocrinology and Internal Medicine, Aarhus, Denmark
- Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - N Rittig
- Departments of Endocrinology and Internal Medicine, Aarhus, Denmark
- Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - S B Pedersen
- Departments of Endocrinology and Internal Medicine, Aarhus, Denmark
| | - N Jessen
- Departments of Clinical Pharmacology, Aarhus University Hospital, Aarhus, Denmark
- Institute of Biomedicine, Aarhus University, Aarhus, Denmark
| | - N Møller
- Departments of Endocrinology and Internal Medicine, Aarhus, Denmark
- Departments of Clinical Pharmacology, Aarhus University Hospital, Aarhus, Denmark
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Perlatti B, Harris G, Nichols CB, Ekanayake DI, Alspaugh JA, Gloer JB, Bills GF. Campafungins: Inhibitors of Candida albicans and Cryptococcus neoformans Hyphal Growth. J Nat Prod 2020; 83:2718-2726. [PMID: 32881504 PMCID: PMC7530089 DOI: 10.1021/acs.jnatprod.0c00641] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Campafungin A is a polyketide that was recognized in the Candida albicans fitness test due to its antiproliferative and antihyphal activity. Its mode of action was hypothesized to involve inhibition of a cAMP-dependent PKA pathway. The originally proposed structure appeared to require a polyketide assembled in a somewhat unusual fashion. However, structural characterization data were never formally published. This background stimulated a reinvestigation in which campafungin A and three closely related minor constituents were purified from fermentations of a strain of the ascomycete fungus Plenodomus enteroleucus. Labeling studies, along with extensive NMR analysis, enabled assignment of a revised structure consistent with conventional polyketide synthetic machinery. The structure elucidation of campafungin A and new analogues encountered in this study, designated here as campafungins B, C, and D, is presented, along with a proposed biosynthetic route. The antimicrobial spectrum was expanded to methicillin-resistant Staphylococcus aureus, Candida tropicalis, Candida glabrata, Cryptococcus neoformans, Aspergillus fumigatus, and Schizosaccharomyces pombe, with MICs ranging as low as 4-8 μg mL-1 in C. neoformans. Mode-of-action studies employing libraries of C. neoformans mutants indicated that multiple pathways were affected, but mutants in PKA/cAMP pathways were unaffected, indicating that the mode of action was distinct from that observed in C. albicans.
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Affiliation(s)
- Bruno Perlatti
- Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas 77054, United States
| | - Guy Harris
- Guy Harris Consulting, 464 Fairview Road, Belington, West Virginia 26250, United States
| | - Connie B Nichols
- Departments of Medicine and Molecular Genetics & Microbiology, Duke University Medical Center, Durham, North Carolina 27710, United States
| | - Dulamini I Ekanayake
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - J Andrew Alspaugh
- Departments of Medicine and Molecular Genetics & Microbiology, Duke University Medical Center, Durham, North Carolina 27710, United States
| | - James B Gloer
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Gerald F Bills
- Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas 77054, United States
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Rahman MS, Kim YS. PINK1-PRKN mitophagy suppression by mangiferin promotes a brown-fat-phenotype via PKA-p38 MAPK signalling in murine C3H10T1/2 mesenchymal stem cells. Metabolism 2020; 107:154228. [PMID: 32289346 DOI: 10.1016/j.metabol.2020.154228] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 03/20/2020] [Accepted: 04/07/2020] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Mangiferin (MF), a xanthonoid derived from Mangifera indica, has shown therapeutic effects on various human diseases including cancer, diabetes, and obesity. Nonetheless, the influence of MF on non-shivering thermogenesis and its underlying mechanism in browning remains unclear. Here, our aim was to investigate the effects of MF on browning and its molecular mechanisms in murine C3H10T1/2 mesenchymal stem cells (MSCs). MATERIALS/METHODS To determine the function of MF on browning, murine C3H10T1/2 MSCs were treated with MF in an adipogenic differentiation cocktail and the thermogenic and correlated metabolic responses were assessed using MF-mediated signalling. Human adipose-derived MSCs were differentiated and treated with MF to confirm its role in thermogenic induction. RESULTS MF treatment induced the expression of a brown-fat signature, UCP1, and reduced triglyceride (TG) in C3H10T1/2 MSCs. MF also induced the expression of major thermogenesis regulators: PGC1α, PRDM16, and PPARγ and up-regulated the expression of beiging markers CD137, HSPB7, TBX1, and COX2 in both murine C3H10T1/2 MSCs and human adipose-derived mesenchymal stem cells (hADMSC). We also observed that MF treatment increased the mitochondrial DNA and improved mitochondrial homeostasis by regulating mitofission-fusion plasticity via suppressing PINK1-PRKN-mediated mitophagy. Furthermore, MF treatment improved mitochondrial respiratory function by increasing mitochondrial oxygen consumption and expression of oxidative-phosphorylation (OXPHOS)-related proteins. Chemical-inhibition and gene knockdown experiments revealed that β3-AR-dependent PKA-p38 MAPK-CREB signalling is crucial for MF-mediated brown-fat formation via suppression of mitophagy in C3H10T1/2 MSCs. CONCLUSIONS MF promotes the brown adipocyte phenotype by suppressing mitophagy, which is regulated by PKA-p38MAPK-CREB signalling in C3H10T1/2 MSCs. Thus, we propose that MF may be a good browning inducer that can ameliorate obesity.
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Affiliation(s)
- Md Shamim Rahman
- Institute of Tissue Regeneration, College of Medicine, Soonchunhyang University, Cheonan, Chung-nam 31151, South Korea; Department of Microbiology, College of Medicine, Soonchunhyang University, Cheonan, Chung-nam 31151, South Korea
| | - Yong-Sik Kim
- Institute of Tissue Regeneration, College of Medicine, Soonchunhyang University, Cheonan, Chung-nam 31151, South Korea; Department of Microbiology, College of Medicine, Soonchunhyang University, Cheonan, Chung-nam 31151, South Korea.
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Mollashahi M, Abbasnejad M, Esmaeili-Mahani S. Spinal protein kinase A and phosphorylated extracellular signal-regulated kinase signaling are involved in the antinociceptive effect of phytohormone abscisic acid in rats. Arq Neuropsiquiatr 2020; 78:21-27. [PMID: 32074185 DOI: 10.1590/0004-282x20190137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 09/05/2019] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The phytohormone abscisic acid (ABA) as a signaling molecule exists in various types of organisms from early multicellular to animal cells and tissues. It has been demonstrated that ABA has an antinociceptive effect in rodents. The present study was designed to assess the possible role of PKA and phosphorylated ERK (p-ERK) on the antinociceptive effects of intrathecal (i.t.) ABA in male Wistar rats. METHODS The animals were cannulated intrathecally and divided into different experimental groups (n=6‒7): Control (no surgery), vehicle (received ABA vehicle), ABA-treated groups (received ABA in doses of 10 or 20 µg/rat), ABA plus H.89 (PKA inhibitor)-treated group which received the inhibitor 15 min prior to the ABA injection. Tail-flick and hot-plate tests were used as acute nociceptive stimulators to assess ABA analgesic effects. p-ERK was evaluated in the dorsal portion of the spinal cord using immunoblotting. RESULTS Data showed that a microinjection of ABA (10 and 20 µg/rat, i.t.) significantly increased the nociceptive threshold in tail flick and hot plate tests. The application of PKA inhibitor (H.89, 100 nM/rat) significantly inhibited ABA-induced analgesic effects. Expression of p-ERK was significantly decreased in ABA-injected animals, which were not observed in the ABA+H.89-treated group. CONCLUSIONS Overall, i.t. administration of ABA (10 µg/rat) induced analgesia and p-ERK down-expression likely by involving the PKA-dependent mechanism.
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Affiliation(s)
- Mahtab Mollashahi
- Shahid Bahonar University of Kerman, Faculty of Sciences, Department of Biology, Kerman, Iran
| | - Mehdi Abbasnejad
- Shahid Bahonar University of Kerman, Faculty of Sciences, Department of Biology, Kerman, Iran
- Kerman University of Medical Sciences, Kerman Neuroscience Research Center (KNRC), Laboratory of Molecular Neuroscience, Kerman, Iran
| | - Saeed Esmaeili-Mahani
- Shahid Bahonar University of Kerman, Faculty of Sciences, Department of Biology, Kerman, Iran
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Zhou HY, He JG, Hu ZL, Xue SG, Xu JF, Cui QQ, Gao SQ, Zhou B, Wu PF, Long LH, Wang F, Chen JG. A-Kinase Anchoring Protein 150 and Protein Kinase A Complex in the Basolateral Amygdala Contributes to Depressive-like Behaviors Induced by Chronic Restraint Stress. Biol Psychiatry 2019; 86:131-142. [PMID: 31076080 DOI: 10.1016/j.biopsych.2019.03.967] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 02/11/2019] [Accepted: 03/05/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND The basolateral amygdala (BLA) has been widely implicated in the pathophysiology of major depressive disorder. A-kinase anchoring protein 150 (AKAP150) directs kinases and phosphatases to synaptic glutamate receptors, controlling synaptic transmission and plasticity. However, the role of the AKAP150 in the BLA in major depressive disorder remains poorly understood. METHODS Depressive-like behaviors in C57BL/6J mice were developed by chronic restraint stress (CRS). Mice received either intra-BLA injection of lentivirus-expressing Akap5 short hairpin RNA or Ht-31, a peptide to disrupt the interaction of AKAP150 and protein kinase A (PKA), followed by depressive-like behavioral tests. Alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid glutamate receptor (AMPAR)-mediated miniature excitatory postsynaptic currents were recorded by whole-cell patch-clamp techniques. RESULTS Chronic stress exposure induced depressive-like behaviors, which were accompanied by an increase in total and synaptic AKAP150 expression in the BLA. Accordingly, CRS facilitated the association of AKAP150 with PKA, but not of calcineurin in the BLA. Intra-BLA infusion of lentivirus-expressing Akap5 short hairpin RNA or Ht-31 prevented depressive-like behaviors and normalized phosphorylation of serine 845 and surface expression of AMPAR subunit 1 (GluA1) in the BLA of CRS mice. Finally, blockage of AKAP150-PKA complex signaling rescued the changes in AMPAR-mediated miniature excitatory postsynaptic currents in depressive-like mice. CONCLUSIONS These results suggest that AKAP150-PKA directly modulates BLA neuronal synaptic strength, and that AKAP150-PKA-GluA1 streamline signaling complex is responsible for CRS-induced disruption of synaptic AMPAR-mediated transmission and depressive-like behaviors in mice.
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Affiliation(s)
- Hai-Yun Zhou
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jin-Gang He
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Research Center for Depression, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Laboratory of Neuropsychiatric Diseases, Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, China; Hubei Key Laboratory of Drug Target Research and Pharmacodynamic Evaluation, Huazhong University of Science and Technology, Wuhan, China; Key Laboratory of Neurological Diseases, Huazhong University of Science and Technology, Ministry of Education of China, Wuhan, China
| | - Zhuang-Li Hu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Laboratory of Neuropsychiatric Diseases, Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, China; Hubei Key Laboratory of Drug Target Research and Pharmacodynamic Evaluation, Huazhong University of Science and Technology, Wuhan, China; Key Laboratory of Neurological Diseases, Huazhong University of Science and Technology, Ministry of Education of China, Wuhan, China
| | - Shi-Ge Xue
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jun-Feng Xu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qian-Qian Cui
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shuang-Qi Gao
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Bin Zhou
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Peng-Fei Wu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Laboratory of Neuropsychiatric Diseases, Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, China; Hubei Key Laboratory of Drug Target Research and Pharmacodynamic Evaluation, Huazhong University of Science and Technology, Wuhan, China; Key Laboratory of Neurological Diseases, Huazhong University of Science and Technology, Ministry of Education of China, Wuhan, China
| | - Li-Hong Long
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Laboratory of Neuropsychiatric Diseases, Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, China; Hubei Key Laboratory of Drug Target Research and Pharmacodynamic Evaluation, Huazhong University of Science and Technology, Wuhan, China; Key Laboratory of Neurological Diseases, Huazhong University of Science and Technology, Ministry of Education of China, Wuhan, China
| | - Fang Wang
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Research Center for Depression, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Laboratory of Neuropsychiatric Diseases, Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, China; Hubei Key Laboratory of Drug Target Research and Pharmacodynamic Evaluation, Huazhong University of Science and Technology, Wuhan, China; Key Laboratory of Neurological Diseases, Huazhong University of Science and Technology, Ministry of Education of China, Wuhan, China.
| | - Jian-Guo Chen
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Research Center for Depression, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Laboratory of Neuropsychiatric Diseases, Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, China; Hubei Key Laboratory of Drug Target Research and Pharmacodynamic Evaluation, Huazhong University of Science and Technology, Wuhan, China; Key Laboratory of Neurological Diseases, Huazhong University of Science and Technology, Ministry of Education of China, Wuhan, China.
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Jiang J, Emont MP, Jun H, Qiao X, Liao J, Kim DI, Wu J. Cinnamaldehyde induces fat cell-autonomous thermogenesis and metabolic reprogramming. Metabolism 2017; 77:58-64. [PMID: 29046261 PMCID: PMC5685898 DOI: 10.1016/j.metabol.2017.08.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 08/07/2017] [Accepted: 08/15/2017] [Indexed: 01/24/2023]
Abstract
OBJECTIVE Cinnamaldehyde (CA) is a food compound that has previously been observed to be protective against obesity and hyperglycemia in mouse models. In this study, we aimed to elucidate the mechanisms behind this protective effect by assessing the cell-autonomous response of primary adipocytes to CA treatment. METHODS Primary murine adipocytes were treated with CA and thermogenic and metabolic responses were assessed after both acute and chronic treatments. Human adipose stem cells were differentiated and treated with CA to assess whether the CA-mediated signaling is conserved in humans. RESULTS CA significantly activated PKA signaling, increased expression levels of thermogenic genes and induced phosphorylation of HSL and PLIN1 in murine primary adipocytes. Inhibition of PKA or p38 MAPK enzymatic activity markedly inhibited the CA-induced thermogenic response. In addition, chronic CA treatment regulates metabolic reprogramming, which was partially diminished in FGF21KO adipocytes. Importantly, both acute and chronic effects of CA were observed in human adipose stem cells isolated from multiple donors of different ethnicities and ages and with a variety of body mass indexes (BMI). CONCLUSIONS CA activates thermogenic and metabolic responses in mouse and human primary subcutaneous adipocytes in a cell-autonomous manner, giving a mechanistic explanation for the anti-obesity effects of CA observed previously and further supporting its potential metabolic benefits on humans. Given the wide usage of cinnamon in the food industry, the notion that this popular food additive, instead of a drug, may activate thermogenesis, could ultimately lead to therapeutic strategies against obesity that are much better adhered to by participants.
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Affiliation(s)
- Juan Jiang
- Life Sciences Institute, 210 Washtenaw Ave Rm 5115, University of Michigan, Ann Arbor, MI, 48109, USA; Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan 410008, PR China
| | - Margo P Emont
- Life Sciences Institute, 210 Washtenaw Ave Rm 5115, University of Michigan, Ann Arbor, MI, 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Heejin Jun
- Life Sciences Institute, 210 Washtenaw Ave Rm 5115, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Xiaona Qiao
- Life Sciences Institute, 210 Washtenaw Ave Rm 5115, University of Michigan, Ann Arbor, MI, 48109, USA; Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai 200040, P.R.China
| | - Jiling Liao
- Life Sciences Institute, 210 Washtenaw Ave Rm 5115, University of Michigan, Ann Arbor, MI, 48109, USA; Department of Endocrinology and Metabolism, 2nd Xiangya Hospital, Central South University, Changsha, Hunan 410011, PR China
| | - Dong-Il Kim
- Life Sciences Institute, 210 Washtenaw Ave Rm 5115, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jun Wu
- Life Sciences Institute, 210 Washtenaw Ave Rm 5115, University of Michigan, Ann Arbor, MI, 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109, USA.
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Möllmann J, Kahles F, Lebherz C, Kappel B, Baeck C, Tacke F, Werner C, Federici M, Marx N, Lehrke M. The PDE4 inhibitor roflumilast reduces weight gain by increasing energy expenditure and leads to improved glucose metabolism. Diabetes Obes Metab 2017; 19:496-508. [PMID: 27917591 DOI: 10.1111/dom.12839] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 11/27/2016] [Accepted: 11/28/2016] [Indexed: 02/06/2023]
Abstract
AIMS To investigate the metabolic effects of the phosphodiesterase-4 (PDE4) inhibitor roflumilast, a clinically approved anti-inflammatory drug used for the treatment of chronic obstructive pulmonary disease. MATERIALS AND METHODS The metabolic effects of roflumilast were investigated in C57BL/6J mice, fed a high-fat Western-type diet and treated with or without roflumilast for a period of 12 weeks. RESULTS Roflumilast led to a marked reduction in body weight gain, which became apparent in the second week after treatment initiation and was attributable to a pronounced increase in energy expenditure. Furthermore, roflumilast improved glucose tolerance, reduced insulin resistance and diminished steatohepatitis in mice. Mechanistically, this was associated with hepatic protein kinase A (PKA) and cAMP response element binding protein (CREB) activation, leading to peroxisome proliferator-activated receptor gamma coactivator-1α (PCG-1α)-dependent induction of mitochondrial biogenesis. Consistently, roflumilast increased the cellular respiratory capacity of hepatocytes in a PKA-dependent manner. CONCLUSION Roflumilast-dependent PDE4 inhibition is a new target for weight loss strategies, especially in conditions of associated comorbidities such as insulin resistance and non-alcoholic steatohepatitis.
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Affiliation(s)
- Julia Möllmann
- Department of Internal Medicine I, University Hospital Aachen, Aachen, Germany
| | - Florian Kahles
- Department of Internal Medicine I, University Hospital Aachen, Aachen, Germany
| | - Corinna Lebherz
- Department of Internal Medicine I, University Hospital Aachen, Aachen, Germany
| | - Ben Kappel
- Department of Internal Medicine I, University Hospital Aachen, Aachen, Germany
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Christer Baeck
- Department of Internal Medicine III, University Hospital Aachen, Aachen, Germany
| | - Frank Tacke
- Department of Internal Medicine III, University Hospital Aachen, Aachen, Germany
| | - Christian Werner
- Department of Internal Medicine III, Saarland University Medical Centre, Homburg, Germany
| | - Massimo Federici
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Nikolaus Marx
- Department of Internal Medicine I, University Hospital Aachen, Aachen, Germany
| | - Michael Lehrke
- Department of Internal Medicine I, University Hospital Aachen, Aachen, Germany
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Xue YT, Li Y, Jiao HC, Liu XJ, Lu YF. [Effect of Fuxin Mixture on The 01-AR-cAMP-PKA Pathway of Rats with Heart Failure]. Zhongguo Zhong Xi Yi Jie He Za Zhi 2017; 37:453-457. [PMID: 30650505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Objective To observe the effect of Fuxin Mixture(FXM) on the β,-AR(adrenergic receptor) -cAMP(cyclic adenosine monophosphate, cAMP) -PKA ( protein kinase A, PKA) pathway of rats with heart failure. Methods Male Wistar rats were randomly divided into blank control group, captopril group, FXM low dose group, FXM high dose group and model group.Models of CHF were established. After drug intervention for 6 weeks, the left ventricular mass index (LVMI) was analysed, the expression of β₁ - AR mRNA in myocardial tissue was measured,the level of cAMP in rat plasma,the OD value PKA content of spleen tissue homogenate were detected. Results Compared with the blank control group, the LVMI and the cAMP in plasma of model group were increased (P <0. 05), the expression of β₁,-AR mRNA, the OD value of spleen tissue homogenate and PKA were decreased (P <0. 01). Compared with the model group, the LVMI were decreased,and the expression of β₁-AR mRNA were increased in FXM high dose group and captopril group (P <0. 01 , P <0. 05) ; the level of cAMP in plasma of each drug group were decreased (P <0. 01) , the OD value of spleen tissue homogenate and PKA were increased (P <0. 01). Compared with the captopril group, the expression of β₁-AR mRNA, the OD value of spleen tissue homogenate and PKA were decreased, and the LVMI and the cAMP were increased in the FXM low dose group (P <0. 01 , P <0. 05). Compared with the FXM low dose group, the LVMI and the cAMP of FXM high dose group were decreased (P <0. 05), the expression of β₁-AR mRNA, the OD value of spleen tissue homogenate and PKA were increased (P <0. 01). Conclusion FXM could play the role of anti-heart fail- ure through regulating P1-AR-cAMP-PKA pathway.
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Zhou L, Sun WL, Weierstall K, Minerly AC, Weiner J, Jenab S, Quinones-Jenab V. Sex differences in behavioral and PKA cascade responses to repeated cocaine administration. Psychopharmacology (Berl) 2016; 233:3527-36. [PMID: 27553823 DOI: 10.1007/s00213-016-4387-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 07/13/2016] [Indexed: 11/26/2022]
Abstract
Previous studies have shown sex different patterns in behavioral responses to cocaine. Here, we used between-subject experiment design to study whether sex differences exist in the development of behavioral sensitization and tolerance to repeated cocaine, as well as the role of protein kinase A (PKA) signaling cascade in this process. Ambulatory and rearing responses were recorded in male and female rats after 1 to 14 days of administration of saline or cocaine (15 mg/kg; ip). Correspondent PKA-associated signaling in the nucleus accumbens (NAc) and caudate-putamen (CPu) was measured at each time point. Our results showed that females exhibited higher cocaine-induced behavioral responses and developed behavioral sensitization and tolerance faster than males. Whereas females developed behavioral sensitization to cocaine after 2 days and tolerance after 14 days, male rats developed sensitization after 5 days. In addition, cocaine induced a sexual dimorphic pattern in the progression of neuronal adaptations on the PKA cascade signaling in region (NAc vs. CPu) and time (days of cocaine administration)-dependent manners. In general, more PKA signaling cascade changes were found in the NAc of males on day 5 and in the CPu of females with repeated cocaine injection. In addition, in females, behavioral activities positively correlated with FosB levels in the NAc and CPu and negatively correlated with Cdk5 and p35 in the CPu, while no correlation was observed in males. Our studies suggest that repeated cocaine administration induced different patterns of behavioral and molecular responses in the PKA cascade in male and female rats.
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Affiliation(s)
- Luyi Zhou
- Department of Biological Sciences, Hunter College of the City University of New York, New York, NY, 10065, USA
- Department of Biology PhD Program, Graduate School and University Center of the City University of New York, New York, NY, 10016, USA
- Department of Drug Discovery and Biomedical Sciences, University of South Carolina, Columbia, SC, 29208, USA
| | - Wei-Lun Sun
- Department of Drug Discovery and Biomedical Sciences, University of South Carolina, Columbia, SC, 29208, USA
- Department of Psychology, Hunter College of the City University of New York, New York, NY, 10065, USA
- Department of Biopsychology and Behavioral Neuroscience PhD Subprogram, Graduate School and University Center of the City University of New York, New York, NY, 10016, USA
| | - Karen Weierstall
- Department of Psychology, Hunter College of the City University of New York, New York, NY, 10065, USA
- Department of Biopsychology and Behavioral Neuroscience PhD Subprogram, Graduate School and University Center of the City University of New York, New York, NY, 10016, USA
| | - Ana Christina Minerly
- Department of Psychology, Hunter College of the City University of New York, New York, NY, 10065, USA
- Department of Biopsychology and Behavioral Neuroscience PhD Subprogram, Graduate School and University Center of the City University of New York, New York, NY, 10016, USA
| | - Jan Weiner
- Department of Psychology, Hunter College of the City University of New York, New York, NY, 10065, USA
- Department of Biopsychology and Behavioral Neuroscience PhD Subprogram, Graduate School and University Center of the City University of New York, New York, NY, 10016, USA
| | - Shirzad Jenab
- Department of Psychology, Hunter College of the City University of New York, New York, NY, 10065, USA
- Department of Biopsychology and Behavioral Neuroscience PhD Subprogram, Graduate School and University Center of the City University of New York, New York, NY, 10016, USA
| | - Vanya Quinones-Jenab
- Department of Biology PhD Program, Graduate School and University Center of the City University of New York, New York, NY, 10016, USA.
- Department of Psychology, Hunter College of the City University of New York, New York, NY, 10065, USA.
- Department of Biopsychology and Behavioral Neuroscience PhD Subprogram, Graduate School and University Center of the City University of New York, New York, NY, 10016, USA.
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Staveness D, Abdelnabi R, Schrier AJ, Loy B, Verma VA, DeChristopher BA, Near KE, Neyts J, Delang L, Leyssen P, Wender PA. Simplified Bryostatin Analogues Protect Cells from Chikungunya Virus-Induced Cell Death. J Nat Prod 2016; 79:675-9. [PMID: 26900625 PMCID: PMC4928627 DOI: 10.1021/acs.jnatprod.5b01016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Indexed: 05/21/2023]
Abstract
Chikungunya virus (CHIKV) is a mosquito-borne alphavirus showing a recent resurgence and rapid spread worldwide. While vaccines are under development, there are currently no therapies to treat this disease, except for over-the-counter (OTC) analgesics, which alleviate the devastating arthritic and arthralgic symptoms. To identify novel inhibitors of the virus, analogues of the natural product bryostatin 1, a clinical lead for the treatment of cancer, Alzheimer's disease, and HIV eradication, were investigated for in vitro antiviral activity and were found to be among the most potent inhibitors of CHIKV replication reported to date. Bryostatin-based therapeutic efforts and even recent anti-CHIKV strategies have centered on modulation of protein kinase C (PKC). Intriguingly, while the C ring of bryostatin primarily drives interactions with PKC, A- and B-ring functionality in these analogues has a significant effect on the observed cell-protective activity. Significantly, bryostatin 1 itself, a potent pan-PKC modulator, is inactive in these assays. These new findings indicate that the observed anti-CHIKV activity is not solely mediated by PKC modulation, suggesting possible as yet unidentified targets for CHIKV therapeutic intervention. The high potency and low toxicity of these bryologs make them promising new leads for the development of a CHIKV treatment.
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Affiliation(s)
- Daryl Staveness
- Departments of Chemistry and Chemical and
Systems Biology, Stanford University, Stanford, California 94305, United States
| | - Rana Abdelnabi
- Department of Microbiology and Immunology, Rega Institute for Medical
Research, Laboratory of Virology and Chemotherapy, KU Leuven−University of Leuven, B-3000 Leuven, Belgium
| | - Adam J. Schrier
- Departments of Chemistry and Chemical and
Systems Biology, Stanford University, Stanford, California 94305, United States
| | - Brian
A. Loy
- Departments of Chemistry and Chemical and
Systems Biology, Stanford University, Stanford, California 94305, United States
| | - Vishal A. Verma
- Departments of Chemistry and Chemical and
Systems Biology, Stanford University, Stanford, California 94305, United States
| | - Brian A. DeChristopher
- Departments of Chemistry and Chemical and
Systems Biology, Stanford University, Stanford, California 94305, United States
| | - Katherine E. Near
- Departments of Chemistry and Chemical and
Systems Biology, Stanford University, Stanford, California 94305, United States
| | - Johan Neyts
- Department of Microbiology and Immunology, Rega Institute for Medical
Research, Laboratory of Virology and Chemotherapy, KU Leuven−University of Leuven, B-3000 Leuven, Belgium
- E-mail:
| | - Leen Delang
- Department of Microbiology and Immunology, Rega Institute for Medical
Research, Laboratory of Virology and Chemotherapy, KU Leuven−University of Leuven, B-3000 Leuven, Belgium
| | - Pieter Leyssen
- Department of Microbiology and Immunology, Rega Institute for Medical
Research, Laboratory of Virology and Chemotherapy, KU Leuven−University of Leuven, B-3000 Leuven, Belgium
| | - Paul A. Wender
- Departments of Chemistry and Chemical and
Systems Biology, Stanford University, Stanford, California 94305, United States
- E-mail:
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11
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Choi DG, Kim EK, Yang JW, Song JS, Kim YM. Nectandrin B, a lignan isolated from nutmeg, inhibits liver X receptor-α-induced hepatic lipogenesis through AMP-activated protein kinase activation. Pharmazie 2015; 70:733-739. [PMID: 26790190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Nonalcoholic fatty liver disease is recognized as the most commonly occurring chronic liver disease. Liver X receptor α (LXRα) and sterol regulatory element-binding protein (SREBP)-1c play a central role in de novo fatty acid synthesis. This study investigated pharmacological effects of nectandrin B, a lignan isolated from nutmeg extract, on hepatic lipogenesis stimulated by LXRα-SREBP-1c-mediated pathway and the possible molecular basis. The reporter gene assay revealed that nectandrin B completely represses LXRα activity enhanced by a synthetic LXRα ligand (T0901317) in HepG2 cells. The inhibitory effect was further supported by the suppression of mRNA expression of LXRα target genes, SREBP-1c and LXRα itself. Nectandrin B also inhibited the increase in SREBP-1c expression promoted by insulin plus high glucose, major contributors to hepatic lipid accumulation. LXRα-SREBP-1c-mediated induction of acetyl-CoA carboxylase 1 and fatty acid synthase, major genes for de novo lipogenesis, was suppressed by nectandrin B. Moreover, Oil Red O staining showed that nectandrin B notably attenuates LXRα-induced lipid accumulation. AMP-activated protein kinase (AMPK) inhibits the activities of LXRα and SREBP-1c. Nectandrin B strongly activated AMPK signaling in HepG2 cells. Taken together, the suppressive effects of nectandrin B on lipogenic gene expression and lipid accumulation in hepatocytes may be due to its inhibitory effect on the LXRα-SREBP-1c pathway presumably via AMPK activation. These results suggest the potential of nectandrin B as a therapeutic candidate for fatty liver disease.
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12
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Reis KP, Heimfarth L, Pierozan P, Ferreira F, Loureiro SO, Fernandes CG, Carvalho RV, Pessoa-Pureur R. High postnatal susceptibility of hippocampal cytoskeleton in response to ethanol exposure during pregnancy and lactation. Alcohol 2015; 49:665-74. [PMID: 26314629 DOI: 10.1016/j.alcohol.2015.06.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 06/08/2015] [Accepted: 06/08/2015] [Indexed: 12/30/2022]
Abstract
Ethanol exposure to offspring during pregnancy and lactation leads to developmental disorders, including central nervous system dysfunction. In the present work, we have studied the effect of chronic ethanol exposure during pregnancy and lactation on the phosphorylating system associated with the astrocytic and neuronal intermediate filament (IF) proteins: glial fibrillary acidic protein (GFAP), and neurofilament (NF) subunits of low, medium, and high molecular weight (NFL, NFM, and NFH, respectively) in 9- and 21-day-old pups. Female rats were fed with 20% ethanol in their drinking water during pregnancy and lactation. The homeostasis of the IF phosphorylation was not altered in the cerebral cortex, cerebellum, or hippocampus of 9-day-old pups. However, GFAP, NFL, and NFM were hyperphosphorylated in the hippocampus of 21-day-old pups. PKA had been activated in the hippocampus, and Ser55 in the N-terminal region of NFL was hyperphosphorylated. In addition, JNK/MAPK was activated and KSP repeats in the C-terminal region of NFM were hyperphosphorylated in the hippocampus of 21-day-old pups. Decreased NFH immunocontent but an unaltered total NFH/phosphoNFH ratio suggested altered stoichiometry of NFs in the hippocampus of ethanol-exposed 21-day-old pups. In contrast to the high susceptibility of hippocampal cytoskeleton in developing rats, the homeostasis of the cytoskeleton of ethanol-fed adult females was not altered. Disruption of the cytoskeletal homeostasis in neural cells supports the view that regions of the brain are differentially vulnerable to alcohol insult during pregnancy and lactation, suggesting that modulation of JNK/MAPK and PKA signaling cascades target the hippocampal cytoskeleton in a window of vulnerability in 21-day-old pups. Our findings are relevant, since disruption of the cytoskeleton in immature hippocampus could contribute to later hippocampal damage associated with ethanol toxicity.
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Affiliation(s)
- Karina Pires Reis
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, RS, Brazil
| | - Luana Heimfarth
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, RS, Brazil
| | - Paula Pierozan
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, RS, Brazil
| | - Fernanda Ferreira
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, RS, Brazil
| | | | | | - Rônan Vivian Carvalho
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, RS, Brazil
| | - Regina Pessoa-Pureur
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, RS, Brazil.
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13
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Zhu J, Ning RB, Lin XY, Chai DJ, Xu CS, Xie H, Zeng JZ, Lin JX. Retinoid X receptor agonists inhibit hypertension-induced myocardial hypertrophy by modulating LKB1/AMPK/p70S6K signaling pathway. Am J Hypertens 2014; 27:1112-24. [PMID: 24603314 DOI: 10.1093/ajh/hpu017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Retinoid X receptor (RXR) has been demonstrated to play an important role in cardiac development and has been implicated in cardiovascular diseases. This study aimed to examine the effects of RXRα agonist bexarotene on pathological left ventricular hypertrophy (LVH) in a spontaneously hypertensive rat (SHR) model and the underlying mechanism. METHODS WKY rats served as controls. SHRs were randomized into 3 groups at the age of 4 weeks and were treated (once daily for 12 weeks) with either bexarotene (30 or 100mg/kg body weight) or vehicle alone. Echocardiography was performed to determine cardiac structure and function. Neonatal cardiomyocytes were treated with AngII (10(-7) mmol/L) with or without the indicated concentration of RXRα ligand 9-cis-RA. The protein abundances of β-actin, RXRα, LKB1, phospho-LKB1, AMPK, phospho-AMPK, P70S6K, phospho-P70S6K, ACE, and AT1 receptor were measured along with blood pressure, body weight and angiotensin II (Ang II) levels. The effects of LKB1 downregulation by LKB1 small, interfering RNA were examined. RESULTS Treatment of SHRs with bexarotene resulted in significant inhibition of LVH without eliminating hypertension. Immunoblot with heart tissue homogenates from SHRs revealed that bexarotene activated the LKB1/AMPK signaling pathway and inhibited p70S6K. However, the increased Ang II levels in SHR serum and heart tissue were not reduced by bexarotene treatment. Treatment of cardiomyocytes with Ang II resulted in significantly reduced LKB1/AMPK activity and increased p70S6K activity. 9-cis-RA antagonized Ang II-induced LKB1/AMPK and p70S6K activation changes in vitro. CONCLUSIONS RXR agonists prevent the inhibition of the LKB1/AMPK/p70S6K pathway and regulate protein synthesis to reduce LVH. This antihypertrophic effect of bexarotene is independent of blood pressure.
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Affiliation(s)
- Jiang Zhu
- First Clinical Medical College, Fujian Medical University, Fuzhou, Fujian, China
| | - Ruo-Bing Ning
- First Clinical Medical College, Fujian Medical University, Fuzhou, Fujian, China
| | - Xiao-Yan Lin
- Echocardiological Department, First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, China
| | - Da-Jun Chai
- Cardiovascular Department, First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, China;
| | - Chang-Sheng Xu
- Cardiovascular Department, First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, China
| | - Hong Xie
- Cardiovascular Department, First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, China
| | - Jin-Zhang Zeng
- School of Pharmaceutical Sciences and Institute for Biomedical Research, Xiamen University, Xiamen, China
| | - Jin-Xiu Lin
- Cardiovascular Department, First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, China;
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14
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Gagnon A, Langille ML, Chaker S, Antunes TT, Durand J, Sorisky A. TSH signaling pathways that regulate MCP-1 in human differentiated adipocytes. Metabolism 2014; 63:812-21. [PMID: 24661543 DOI: 10.1016/j.metabol.2014.02.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 02/25/2014] [Accepted: 02/25/2014] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Adipose tissue is an extra-thyroidal thyroid-stimulating hormone (TSH) target. Increases in lipolysis and in expression and release of interleukin-6 (IL-6) occur in TSH-stimulated adipocytes, and levels of circulating free fatty acids and IL-6 rise following TSH administration to patients with previous thyroidectomy and radioablation for thyroid cancer. Our first objective was to compare how TSH stimulates protein kinase A (PKA) and inhibitor of κB (IκB) kinase (IKK)-β. Our second objective was to investigate whether TSH induces other cytokines besides IL-6. METHODS TSH stimulation of either CHO cells expressing human TSH receptor or human abdominal subcutaneous differentiated adipocytes. RESULTS Signaling studies showed TSH increased NADPH oxidase activity, and either diphenyleneiodonium (oxidase inhibitor) or N-acetyl cysteine (scavenger of reactive oxygen species) reduced IKKβ phosphorylation. Phosphorylation of protein kinase C-δ, an upstream regulator of NADPH oxidase, was increased by TSH, and rottlerin (PKCδ inhibitor) reduced TSH-stimulated IKKβ phosphorylation. TSH upregulated monocyte chemoattractant protein-1 (MCP-1) mRNA expression and the release of MCP-1 protein in human abdominal differentiated adipocytes. H89 (PKA inhibitor) and sc-514 (IKKβ inhibitor) each blocked TSH-stimulated MCP-1 mRNA expression and protein release, suggesting PKA and IKKβ participate in this pathway. CONCLUSIONS These data provide new information about TSH signaling in human differentiated adipocytes, and add to the evidence that TSH is a pro-inflammatory stimulus of adipocytes.
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Affiliation(s)
- AnneMarie Gagnon
- Chronic Disease Program, Ottawa Hospital Research Institute, Departments of Medicine and of Biochemistry, Microbiology & Immunology, University of Ottawa, Ottawa, Ontario, Canada; Chronic Disease Program, Ottawa Hospital Research Institute, Department of Biochemistry, Microbiology & Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Melanie L Langille
- Chronic Disease Program, Ottawa Hospital Research Institute, Departments of Medicine and of Biochemistry, Microbiology & Immunology, University of Ottawa, Ottawa, Ontario, Canada; Chronic Disease Program, Ottawa Hospital Research Institute, Department of Biochemistry, Microbiology & Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Seham Chaker
- Chronic Disease Program, Ottawa Hospital Research Institute, Departments of Medicine and of Biochemistry, Microbiology & Immunology, University of Ottawa, Ottawa, Ontario, Canada; Chronic Disease Program, Ottawa Hospital Research Institute, Department of Biochemistry, Microbiology & Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Tayze T Antunes
- Chronic Disease Program, Ottawa Hospital Research Institute, Departments of Medicine and of Biochemistry, Microbiology & Immunology, University of Ottawa, Ottawa, Ontario, Canada; Chronic Disease Program, Ottawa Hospital Research Institute, Department of Biochemistry, Microbiology & Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Jason Durand
- Chronic Disease Program, Ottawa Hospital Research Institute, Departments of Medicine and of Biochemistry, Microbiology & Immunology, University of Ottawa, Ottawa, Ontario, Canada; Chronic Disease Program, Ottawa Hospital Research Institute, Department of Biochemistry, Microbiology & Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Alexander Sorisky
- Chronic Disease Program, Ottawa Hospital Research Institute, Departments of Medicine and of Biochemistry, Microbiology & Immunology, University of Ottawa, Ottawa, Ontario, Canada; Chronic Disease Program, Ottawa Hospital Research Institute, Department of Biochemistry, Microbiology & Immunology, University of Ottawa, Ottawa, Ontario, Canada.
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15
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Abstract
Clarification of the molecular mechanisms of insulin secretion is crucial for understanding the pathogenesis and pathophysiology of diabetes and for development of novel therapeutic strategies for the disease. Insulin secretion is regulated by various intracellular signals generated by nutrients and hormonal and neural inputs. In addition, a variety of glucose-lowering drugs including sulfonylureas, glinide-derivatives, and incretin-related drugs such as dipeptidyl peptidase IV (DPP-4) inhibitors and glucagon-like peptide 1 (GLP-1) receptor agonists are used for glycaemic control by targeting beta cell signalling for improved insulin secretion. There has been a remarkable increase in our understanding of the basis of beta cell signalling over the past two decades following the application of molecular biology, gene technology, electrophysiology and bioimaging to beta cell research. This review discusses cell signalling in insulin secretion, focusing on the molecular targets of ATP, cAMP and sulfonylurea, an essential metabolic signal in glucose-induced insulin secretion (GIIS), a critical signal in the potentiation of GIIS, and the commonly used glucose-lowering drug, respectively.
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Affiliation(s)
- S Seino
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, 650-0017, Japan.
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16
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Abstract
Triptolide, a major active component of Tripterygium wilfordii Hook F (TWHF), is known to have multiple pharmacological activities. However, studies have also shown that triptolide is highly toxic to the reproductive system by disrupting normal androgen and estrogen signaling. In the present study, we investigated the effect of triptolide (5, 10, or 20 nM for 24 h) on estradiol production by rat granulosa cells. Triptolide inhibited basal and human chorionic gonadotropin (HCG)- or 8-bromo-cAMP-stimulated estradiol production as revealed by RIA assay. Furthermore, the HCG-evoked increase in cellular cAMP content was also inhibited by triptolide, indicating that disruption of the cAMP/PKA signaling pathway may mediate the deleterious effects of triptolide on steroid hormone regulation. In addition, (3)H(2)O tests showed that aromatase activity was significantly inhibited by triptolide in granulosa cells. Western blot and quantitative real-time PCR (qRT-PCR) assays further revealed that triptolide decreased protein and mRNA expression of aromatase in granulosa cells. Moreover, mRNA expression of luteinizing hormone receptor (LHR) was induced by triptolide also using qRT-PCR method. In contrast, cell viability tests using Cell Counting Kit-8 (CCK-8) and 3-(4,5-dimethyl-thiazol-2-yl)-2,5- diphenyl-tetrazolium bromide (MTT) method indicated that triptolide did not cause measurable cell death at doses that suppressed steroidogenesis. The reproductive toxicity of triptolide may be mainly caused by disruption of cAMP/PKA-mediated expression of estrogen synthesis enzymes, leading to reduced estradiol synthesis and reproductive dysfunction.
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Affiliation(s)
- Juan Zhang
- Jiangsu Center of Drug Screening, China Pharmaceutical University, Nanjing, PR China
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17
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Jian D, Jiang D, Su J, Chen W, Hu X, Kuang Y, Xie H, Li J, Chen X. Diethylstilbestrol enhances melanogenesis via cAMP-PKA-mediating up-regulation of tyrosinase and MITF in mouse B16 melanoma cells. Steroids 2011; 76:1297-304. [PMID: 21745488 DOI: 10.1016/j.steroids.2011.06.008] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 06/21/2011] [Accepted: 06/22/2011] [Indexed: 11/19/2022]
Abstract
BACKGROUND It is well known that melanin synthesis in melanoma cells is controlled by melanogenic enzymes, which regulate the cAMP-PKA signaling pathway. Estrogen was previously reported to upregulate melanogenesis that is associated with human skin pigmentation. OBJECTIVE To investigate the influence and mechanism of diethylstilbestrol (DES) on melanogenesis in mouse B16 melanoma cells. METHODS The effects of diethylstilbestrol on cell viability, melanin content, tyrosinase activity, cAMP level, expression of the tyrosinase family and microphthalmia related transcription factor (MITF) were measured in B16 melanoma. Estrogen receptor (ER) expression were detected in B16 melanoma and A375 melanoma. Diethylstilbestrol-induced melanin synthesis were evaluated in the presence and absence of H89 (a PKA-specific inhibitor) and ICI182, 780 (a pure ER antagonist). Tyrosinase activity, the mRNA levels of tyrosinase and MITF were evaluated in the presence and absence of H89. RESULTS In B16 cells, diethylstilbestrol increased cell proliferation, melanin synthesis, tyrosinase activity and expression of the tyrosinase family and MITF. ER expression have not difference in human and mouse melanoma. When ER were inhibited by ICI182, 780, DES-induced melanogenesis was significantly reduced. Diethylstilbestrol enhanced the level of cAMP. The upregulation of melanin content and tyrosinase activity stimulated by diethylstilbestrol was significantly attenuated in the presence of H89. Further, diethylstilbestrol-induced upregulation of tyrosinase and MITF were significantly attenuated when the PKA pathway was blocked. CONCLUSIONS Diethylstilbestrol can enhance melanin synthesis in melanoma cells. This effect is associated with activation of the cAMP-PKA pathway and upregulation of expression and activity of the melanogenesis-related enzyme tyrosinase and MITF.
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Affiliation(s)
- Dan Jian
- Department of Dermatology, XiangYa Hospital, Central South University, Changsha, Hunan, China
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18
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Yu HP, Hsieh PW, Chang YJ, Chung PJ, Kuo LM, Hwang TL. 2-(2-Fluorobenzamido)benzoate ethyl ester (EFB-1) inhibits superoxide production by human neutrophils and attenuates hemorrhagic shock-induced organ dysfunction in rats. Free Radic Biol Med 2011; 50:1737-48. [PMID: 21457779 DOI: 10.1016/j.freeradbiomed.2011.03.026] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 03/02/2011] [Accepted: 03/23/2011] [Indexed: 12/20/2022]
Abstract
Neutrophil activation after trauma-hemorrhagic shock (T/H) has been implicated in the development of multiple organ dysfunction (MOD). In this study, we report that a small chemical compound, 2-(2-fluorobenzamido)benzoic acid ethyl ester (EFB-1), exhibited a potent inhibitory effect on the formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP)-induced superoxide anion (O2•-) release and CD11b expression by human neutrophils. Additionally, administration of EFB-1 in rats subjected to T/H caused a significant improvement in MOD. EFB-1 treatment induced an increase in cAMP formation and protein kinase (PK) A activity in FMLP-activated neutrophils, which occurred through the selective inhibition of cAMP-specific phosphodiesterase (PDE) activity but not an increase in adenylate cyclase function or cGMP-specific PDE activity. FMLP-induced phosphorylation of protein kinase B (AKT), but not calcium mobilization, was reduced by EFB-1. The inhibitory effects of EFB-1 on O(2•-) production, CD11b expression, and AKT phosphorylation were reversed by PKA inhibitors (H89 and KT5720). Significantly, administration of EFB-1 (1 mg/kg body wt) attenuated the myeloperoxidase activity of the intestines, lungs, and liver and reduced the wet/dry weight ratio of the intestines and lungs and plasma alanine aminotransferase and aspartate aminotransferase levels in Sprague-Dawley rats after T/H. Therefore, EFB-1 is a new inhibitor of cAMP-specific PDE that potently suppresses O(2•-) release and CD11b expression by human neutrophils and attenuates T/H-induced MOD in rats.
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Affiliation(s)
- Huang-Ping Yu
- Department of Anesthesiology, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan
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Kothmann WW, Massey SC, O'Brien J. Dopamine-stimulated dephosphorylation of connexin 36 mediates AII amacrine cell uncoupling. J Neurosci 2009; 29:14903-11. [PMID: 19940186 PMCID: PMC2839935 DOI: 10.1523/jneurosci.3436-09.2009] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Revised: 09/24/2009] [Accepted: 10/16/2009] [Indexed: 11/21/2022] Open
Abstract
Gap junction proteins form the substrate for electrical coupling between neurons. These electrical synapses are widespread in the CNS and serve a variety of important functions. In the retina, connexin 36 (Cx36) gap junctions couple AII amacrine cells and are a requisite component of the high-sensitivity rod photoreceptor pathway. AII amacrine cell coupling strength is dynamically regulated by background light intensity, and uncoupling is thought to be mediated by dopamine signaling via D(1)-like receptors. One proposed mechanism for this uncoupling involves dopamine-stimulated phosphorylation of Cx36 at regulatory sites, mediated by protein kinase A. Here we provide evidence against this hypothesis and demonstrate a direct relationship between Cx36 phosphorylation and AII amacrine cell coupling strength. Dopamine receptor-driven uncoupling of the AII network results from protein kinase A activation of protein phosphatase 2A and subsequent dephosphorylation of Cx36. Protein phosphatase 1 activity negatively regulates this pathway. We also find that Cx36 gap junctions can exist in widely different phosphorylation states within a single neuron, implying that coupling is controlled at the level of individual gap junctions by locally assembled signaling complexes. This kind of synapse-by-synapse plasticity allows for precise control of neuronal coupling, as well as cell-type-specific responses dependent on the identity of the signaling complexes assembled.
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Affiliation(s)
- W Wade Kothmann
- Richard S. Ruiz Department of Ophthalmology, University of Texas Medical School at Houston, Houston, Texas 77030, USA.
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20
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Abstract
Insulin secretion is regulated by a series of complex events generated by various intracellular signals including Ca(2+), ATP, cAMP and phospholipid-derived signals. Glucose-stimulated insulin secretion is the principal mode of insulin secretion, and the mechanism potentiating the secretion is critical for physiological responses. Among the various intracellular signals involved, cAMP is particularly important for amplifying insulin secretion. Recently, glucagon-like peptide-1 (GLP-1) analogues and dipeptidyl peptidase-IV (DPP-IV) inhibitors have been developed as new antidiabetic drugs. These drugs all act through cAMP signalling in pancreatic beta-cells. Until recently, cAMP was generally thought to potentiate insulin secretion through protein kinase A (PKA) phosphorylation of proteins associated with the secretory process. However, it is now known that in addition to PKA, cAMP has other targets such as Epac (also referred to as cAMP-GEF). The variety of the effects mediated by cAMP signalling may be linked to cAMP compartmentation in the pancreatic beta-cells.
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Affiliation(s)
- S Seino
- Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Hyogo, Japan.
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Moldovan SM, Nervina JM, Tetradis S, Camargo PM. Regulation of Nur77 gene expression by prostanoids in cementoblastic cells. Arch Oral Biol 2009; 54:412-9. [PMID: 19237150 DOI: 10.1016/j.archoralbio.2009.01.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Revised: 12/18/2008] [Accepted: 01/26/2009] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The inflammatory cytokine interleukin-1 (IL-1) decreases mineralisation by immortalized mouse-derived cementoblastic cells (OC-CM cells), whilst various prostanoids, including fluprostenol (flup) increase it. Subtraction hybridisation conducted on flup minus IL-1-treated OC-CM cells revealed that one of the primary response genes preferentially induced by flup is the transcription factor Nur77. The objective of this study was to examine the signal transduction cascades regulating prostanoid induction of Nur77 gene expression in OC-CM cells. METHODS Confluent OC-CM cells were treated with prostaglandin E(2) (PGE(2)), prostaglandin F(2alpha) (PGF(2alpha)), specific activators of the various EP prostanoid receptors and of the FP prostanoid receptor, and direct activators/inhibitors of the cyclic AMP-protein kinase A (PKA), protein kinase C (PKC) and intracellular calcium pathways. Nur77 gene expression was examined by mRNA extraction and Northern blot analysis. RESULTS PGE(2) and PGF(2alpha) treatment of OC-CM cells significantly increased Nur77 mRNA expression in a time- and dose-dependent fashion. Both the EP1 prostanoid receptor-specific activator 16,16-dimethyl-PGE(2) and the FP prostanoid receptor-specific activator flup significantly increased Nur77 gene expression by OC-CM cells as compared to vehicle-treated controls. Increase in Nur77 gene expression was also observed when direct activators of the PKA, PKC and intracellular calcium pathways were used to treat OC-CM cells. Direct inhibition of the PKA, PKC and intracellular calcium pathways abrogated Nur77 gene expression induced by OC-CM cell treatment with PGE(2) and PGF(2alpha). CONCLUSION Nur77 is a primary gene expressed by OC-CM cells and its induction appears to be mediated by the PKA, PKC and intracellular calcium pathways. Nur77 may affect expression of downstream target genes in OC-CM cells and partially regulate cementoblast cell function.
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Affiliation(s)
- Sanda M Moldovan
- Division of Associated Clinical Specialties, Section of Periodontics, School of Dentistry, University of California, Los Angeles, CA 90095, United States
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Jin CM, Yang YJ, Huang HS, Lim SC, Kai M, Lee MK. Induction of dopamine biosynthesis by l-DOPA in PC12 cells: implications of L-DOPA influx and cyclic AMP. Eur J Pharmacol 2008; 591:88-95. [PMID: 18602388 DOI: 10.1016/j.ejphar.2008.06.052] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 06/04/2008] [Accepted: 06/12/2008] [Indexed: 11/19/2022]
Abstract
The effects of 3,4-dihydroxyphenylalanine (l-DOPA) on dopamine biosynthesis and cytotoxicity were investigated in PC12 cells. l-DOPA treatment (20-200 microM) increased the levels of dopamine by 226%-504% after 3-6 h of treatment and enhanced the activities of tyrosine hydroxylase (TH) and aromatic l-amino acid decarboxylase (AADC). l-DOPA (20-200 muM) treatment led to a 562%-937% increase in l-DOPA influx at 1 h, which inhibited the activity of TH, but not AADC, during the same period. The extracellular releases of dopamine were also increased by 231%-570% after treatment with 20 and 200 microM l-DOPA for 0.5-3 h. l-DOPA at a concentration of 100-200 microM, but not 20 microM, exerted apoptotic cytotoxicity towards PC12 cells for 24-48 h. l-DOPA (20-200 microM) increased the intracellular cyclic AMP levels by 318%-557% after 0.5-1 h in a concentration-dependent manner. However, the elevated cyclic AMP levels by l-DOPA could not protect against l-DOPA (100-200 microM)-induced cytotoxicity after 24-48 h. In addition, l-DOPA (20-200 microM)-induced increases in cyclic AMP and dopamine were significantly reduced by treatment with SCH23390 (dopamine D(1) receptor antagonist). The increased levels of dopamine by l-DOPA were also reduced by H89 (protein kinase A, PKA, inhibitor) and GF109203X (protein kinase C inhibitor); however, the reduction by GF109203X was not significant. l-DOPA at 20-200 microM stimulated the phosphorylation of PKA and cyclic AMP-response element binding protein and induced the biosynthesis of the TH protein. These results indicate that 20-200 microM l-DOPA induces dopamine biosynthesis by two pathways. One pathway involves l-DOPA directly entering the cells to convert dopamine through AADC activity (l-DOPA decarboxylation). The other pathway involves l-DOPA and/or released dopamine activating TH to enhance dopamine biosynthesis by the dopamine D(1) receptor-cyclic AMP-PKA signaling system (dopamine biosynthesis by TH).
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Affiliation(s)
- Chun Mei Jin
- College of Pharmacy and Research Center for Bioresource and Health, Chungbuk National University, Cheongju 361-763, Republic of Korea
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Manickavasagam S, Ye Y, Lin Y, Perez-Polo RJ, Huang MH, Lui CY, Hughes MG, McAdoo DJ, Uretsky BF, Birnbaum Y. The cardioprotective effect of a statin and cilostazol combination: relationship to Akt and endothelial nitric oxide synthase activation. Cardiovasc Drugs Ther 2008; 21:321-30. [PMID: 17620005 DOI: 10.1007/s10557-007-6036-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND Atorvastatin (ATV) protects against ischemia-reperfusion by upregulating Akt and subsequently, endothelial nitric oxide synthase (eNOS) phosphorylation at Ser-1177. However, when given orally, high doses of ATV (10 mg/kg/d) are needed to achieve maximal protective effect in the rat. Protein kinase A (PKA) also phosphorylates eNOS at Ser-1177. As PKA activity depends on cAMP, cilostazol (CIL), a phosphodiesterase type III inhibitor, may stimulate NO production by activating PKA. HYPOTHESIS CIL and ATV may have synergistic effects on eNOS phosphorylation and myocardial infarct size (IS) reduction. METHODS Sprague-Dawley rats received 3-day oral pretreatment with: (1) water; (2) low dose ATV (2 mg/kg/d); (3) CIL (20 mg/kg/d): (4) ATV+CIL. Rats underwent 30 min coronary artery occlusion and 4 h reperfusion, or hearts explanted for immunoblotting without being subjected to ischemia. Area at risk (AR) was assessed by blue dye and IS by triphenyl-tetrazolium-chloride. RESULTS Body weight and the size of AR were comparable among groups. There were no significant differences among groups in mean blood pressure and heart rate. CIL, but not ATV, reduced IS. IS in the ATV+CIL group was significantly smaller than the other three groups (P < 0.001 for each comparison). ATV, CIL and their combination did not affect total eNOS expression. ATV at 2 mg/kg/d did not affect Ser-1177 P-eNOS levels, whereas CIL increased it (258 +/- 15%). The level of myocardial P-eNOS levels was highest in the ATV+CIL group (406 +/- 7%). CONCLUSIONS ATV and CIL have synergistic effect on eNOS phosphorylation and IS reduction. By increased activation of eNOS, CIL may augment the pleiotropic effects of statins.
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Su W, Zhang Z, Zhang J, Yu B. [The effect of recombinant TSBP on protein kinase A activity]. Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 2007; 24:1334-1342. [PMID: 18232488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
To investigate the function of testis sperm binding protein (TSBP) in sperm capacitation and acrosome reaction, the effect of the recombinant TSBP on the activity of protein kinase A was detected in the transfected cell line. With the use of prokaryotic expressing plasmid pGEX-5X-1/tsbp as template, the novel gene tsbp was amplified by PCR and a eukaryotic expressing vector pcDNA3.1/myc-His(-)B/tsbp was constructed. DNA sequencing and restriction endonuclease digestion analysis indicated that the eukaryotic expression vector pcDNA3.1/myc-His(-)B/tsbp had been constructed successfully. After the recombinant plamid being transfected into HEK293 cells, Western blot verified the expression of tsbp. Fusion protein His6-TSBP was purified from the cell lysate by immobilized metal-ion affinity chromatography (IMAC). Radioautograph revealed a higher PKA activity in the transfected HEK293 cells than in the control group, which indicates that TSBP can increase the activity of PKA.
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Affiliation(s)
- Wenhui Su
- Department of Biochemistry and Molecular Biology, China Medical University, Shenyang 110001, China
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25
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Scheggi S, Raone A, De Montis MG, Tagliamonte A, Gambarana C. Behavioral expression of cocaine sensitization in rats is accompanied by a distinct pattern of modifications in the PKA/DARPP-32 signaling pathway. J Neurochem 2007; 103:1168-83. [PMID: 17680995 DOI: 10.1111/j.1471-4159.2007.04818.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Repeated cocaine administration induces behavioral sensitization and modifications in the phosphorylation pattern of dopamine and cAMP-regulated phosphoprotein of Mr 32,000 (DARPP-32), characterized by a tonic increase in the Thr75 phosphorylated form, and a decrease in the Thr34 phosphorylated form. This study further investigated the correlations between cocaine sensitization and modifications in the DARPP-32 phosphorylation pattern, cAMP-dependent protein kinase (PKA) activity, and mGluR5 tone in the medial prefrontal cortex and nucleus accumbens. Behavioral sensitization and modifications in these neurochemical markers followed a similar temporal pattern. Moreover, in sensitized rats acute cocaine administration modified phosphorylation levels of Thr75- and Thr34-DARPP-32, GluR1, and NR1 subunits in the nucleus accumbens only at a dose double the efficacious dose in control rats. These results suggest that the high levels of phospho-Thr75 DARPP-32 maintain PKA in a prevalent inhibited state. Furthermore, in sensitized rats the acute administration of 6-methyl-2-(phenylethynyl)-pyridine, a mGluR5 antagonist, reinstated the phosphorylation levels of Thr75- and Thr34-DARPP-32, GluR1, and NR1 to control values, and a subsequent cocaine challenge did not elicit a sensitized response. These data suggest that a tonic increase in mGluR5 transmission in cocaine-sensitized rats sustains both the increase in phospho-Thr75 DARPP-32 levels and the expression of behavioral sensitization.
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MESH Headings
- Animals
- Behavior, Animal/drug effects
- Behavior, Animal/physiology
- Brain/drug effects
- Brain/metabolism
- Brain/physiopathology
- Cocaine/pharmacology
- Cocaine-Related Disorders/metabolism
- Cocaine-Related Disorders/physiopathology
- Cyclic AMP-Dependent Protein Kinases/drug effects
- Cyclic AMP-Dependent Protein Kinases/metabolism
- Cyclin-Dependent Kinase 5/drug effects
- Cyclin-Dependent Kinase 5/metabolism
- Disease Models, Animal
- Dopamine Uptake Inhibitors/pharmacology
- Dopamine and cAMP-Regulated Phosphoprotein 32/drug effects
- Dopamine and cAMP-Regulated Phosphoprotein 32/metabolism
- Dose-Response Relationship, Drug
- Excitatory Amino Acid Antagonists/pharmacology
- Male
- Nucleus Accumbens/drug effects
- Nucleus Accumbens/metabolism
- Phosphorylation/drug effects
- Prefrontal Cortex/drug effects
- Prefrontal Cortex/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptor, Metabotropic Glutamate 5
- Receptors, AMPA/drug effects
- Receptors, AMPA/metabolism
- Receptors, Metabotropic Glutamate/drug effects
- Receptors, Metabotropic Glutamate/metabolism
- Receptors, N-Methyl-D-Aspartate/drug effects
- Receptors, N-Methyl-D-Aspartate/metabolism
- Signal Transduction/drug effects
- Signal Transduction/physiology
- Up-Regulation/drug effects
- Up-Regulation/physiology
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Affiliation(s)
- Simona Scheggi
- Department of Neuroscience, Pharmacology Unit, University of Siena, Siena, Italy
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Abstract
Impaired cognition and memory may be associated with down-regulation of cAMP-response element-binding protein (CREB) in the brain in patients with Alzheimer disease, but the molecular mechanism leading to the down-regulation is not understood. In this study, we found a selective reduction in the levels of the regulatory subunits (RIIalpha and RIIbeta) and the catalytic subunit (Cbeta) as well as the enzymatic activity of cAMP-dependent protein kinase (PKA), which is the major positive regulator of CREB. We also observed that PKA subunits were proteolyzed by calpain and the levels of PKA subunits correlated negatively with calpain activation in the human brain. These findings led us to propose that in the brain in patients with Alzheimer disease, over-activation of calpain because of calcium dysregulation causes increased degradation and thus decreased activity of PKA, which, in turn, contributes to down-regulation of CREB and impaired cognition and memory.
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Affiliation(s)
- Zhihou Liang
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, USA
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Qi H, Zheng X, Qin X, Dou D, Xu H, Raj JU, Gao Y. Protein kinase G regulates the basal tension and plays a major role in nitrovasodilator-induced relaxation of porcine coronary veins. Br J Pharmacol 2007; 152:1060-9. [PMID: 17891157 PMCID: PMC2095098 DOI: 10.1038/sj.bjp.0707479] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE Coronary venous activity is modulated by endogenous and exogenous nitrovasodilators. The present study was to determine the role of protein kinase G (PKG) in the regulation of the basal tension and nitrovasodilator-induced relaxation of coronary veins. EXPERIMENTAL APPROACH Effects of a PKG inhibitor on the basal tension and responses induced by nitroglycerin, DETA NONOate, and 8-Br-cGMP in isolated porcine coronary veins were determined. Cyclic cGMP was measured with radioimmunoassay. PKG activity was determined by measuring the incorporation of 32P from gamma-32P-ATP into the specific substrate BPDEtide. KEY RESULTS Rp-8-Br-PET-cGMPS, a specific PKG inhibitor, increased the basal tension of porcine coronary veins and decreased PKG activity. The increase in tension was 38% of that caused by nitro-L-arginine. Relaxation of the veins induced by nitroglycerin and DETA NONOate was accompanied with increases in cGMP content and PKG activity. These effects were largely eliminated by inhibiting soluble guanylyl cyclase with ODQ. The increase in PKG activity induced by the nitrovasodilators was abolished by Rp-8-Br-PET-cGMPS. The relaxation caused by these dilators and by 8-Br-cGMP at their EC50 was attenuated by the PKG inhibitor by 51-66%. CONCLUSIONS AND IMPLICATIONS These results suggest that PKG is critically involved in nitric oxide-mediated regulation of the basal tension in porcine coronary veins and that it plays a primary role in relaxation induced by nitrovasodilators. Since nitric oxide plays a key role in modulating coronary venous activity, augmentation of PKG may be a therapeutic target for improving coronary blood flow.
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Affiliation(s)
- H Qi
- Department of Physiology and Pathophysiology, Peking University Health Science Center Beijing, China
| | - X Zheng
- Department of Physiology and Pathophysiology, Peking University Health Science Center Beijing, China
| | - X Qin
- Department of Physiology and Pathophysiology, Peking University Health Science Center Beijing, China
| | - D Dou
- Department of Physiology and Pathophysiology, Peking University Health Science Center Beijing, China
| | - H Xu
- Department of Physiology and Pathophysiology, Peking University Health Science Center Beijing, China
| | - J U Raj
- Division of Neonatology, Harbor-UCLA Medical Center, University of California at Los Angeles Geffen School of Medicine Los Angeles, CA, USA
| | - Y Gao
- Department of Physiology and Pathophysiology, Peking University Health Science Center Beijing, China
- Key Laboratory of Molecular Cardiovascular Sciences (Peking University), Ministry of Education Beijing, China
- Author for correspondence:
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O'Driscoll C, Wallace D, Cotter TG. bFGF promotes photoreceptor cell survival in vitro by PKA-mediated inactivation of glycogen synthase kinase 3beta and CREB-dependent Bcl-2 up-regulation. J Neurochem 2007; 103:860-70. [PMID: 17714451 DOI: 10.1111/j.1471-4159.2007.04827.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Although there is substantial evidence supporting the neuroprotective efficacy of basic fibroblast growth factor (bFGF) in the rodent retina there is no consensus to date as to the protective mechanism involved. We hypothesise that bFGF can assert its neuroprotective effects directly on mouse photoreceptors transduced via the activation of specific intracellular signalling pathways. In mouse photoreceptor-derived 661W cells, bFGF promoted a rapid inactivation of glycogen synthase kinase 3beta (GSK3beta) by phosphorylation at Ser9. The effects of bFGF on GSK3beta were dependent on protein kinase A (PKA) activation, as inhibition of this pathway blocked inactivation. Furthermore, bFGF protection against oxidative stress was dependent on PKA inactivation of GSK3beta as PKA inhibition attenuated bFGF-induced protection. Furthermore, transfection of cells with mutant dominant negative GSK3betaS9A that cannot be phosphorylated on Ser9 also abrogated neuroprotection. Activation of the transcription factor cAMP-response element binding protein (CREB) and subsequent up-regulation of Bcl-2 in response to bFGF was also dependent on PKA as inhibition with H-89 attenuated increased pCREB levels and Bcl-2 expression. These results indicate that the protective efficacy of bFGF in mouse photoreceptors involves PKA-dependent inactivation of GSK3beta and subsequent up-regulation of Bcl-2 via CREB activation.
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Affiliation(s)
- Carolyn O'Driscoll
- Cell Development and Disease Laboratory, Biochemistry Department, Bioscience Research Institute, University College Cork, Cork, Ireland
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29
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Wu BN, Chen CF, Hong YR, Howng SL, Lin YL, Chen IJ. Activation of BKCa channels via cyclic AMP- and cyclic GMP-dependent protein kinases by eugenosedin-A in rat basilar artery myocytes. Br J Pharmacol 2007; 152:374-85. [PMID: 17700725 PMCID: PMC2042951 DOI: 10.1038/sj.bjp.0707406] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE The study investigated whether eugenosedin-A, a 5-hydroxytryptamine and alpha/beta adrenoceptor antagonist, enhanced delayed-rectifier potassium (K(DR))- or large-conductance Ca(2+)-activated potassium (BK(Ca))-channel activity in basilar artery myocytes through cyclic AMP/GMP-dependent and -independent protein kinases. EXPERIMENTAL APPROACH Cerebral smooth muscle cells (SMCs) were enzymatically dissociated from rat basilar arteries. Conventional whole cell, perforated and inside-out patch-clamp electrophysiology was used to monitor K(+)- and Ca(2+)-channel activities. KEY RESULTS Eugenosedin-A (1 microM) did not affect the K(DR) current but dramatically augmented BK(Ca) channel activity in a concentration-dependent manner. Increased BK(Ca) current was abolished by charybdotoxin (ChTX, 0.1 microM) or iberiotoxin (IbTX, 0.1 microM), but not affected by a small-conductance K(Ca) blocker (apamin, 100 microM). BK(Ca) current activation by eugenosedin-A was significantly inhibited by an adenylate cyclase inhibitor (SQ 22536, 10 microM), a soluble guanylate cyclase inhibitor (ODQ, 10 microM), competitive antagonists of cAMP and cGMP (Rp-cAMP, 100 microM and Rp-cGMP, 100 microM), and cAMP- and cGMP-dependent protein kinase inhibitors (KT5720, 0.3 microM and KT5823, 0.3 microM). Eugenosedin-A reversed the inhibition of BK(Ca) current induced by the protein kinase C activator, phorbol myristyl acetate (PMA, 0.1 microM). Eugenosedin-A also prevented BK(Ca) current inhibition induced by adding PMA, KT5720 and KT5823. Moreover, eugenosedin-A reduced the amplitude of voltage-dependent L-type Ca(2+) current (I(Ca,L)), but without modifying the voltage-dependence of the current. CONCLUSIONS AND IMPLICATIONS Eugenosedin-A enhanced BK(Ca) currents by stimulating the activity of cyclic nucleotide-dependent protein kinases. Physiologically, this activation would result in the closure of voltage-dependent calcium channels and thereby relax cerebral SMCs.
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Affiliation(s)
- B-N Wu
- Department and Graduate Institute of Pharmacology, College of Medicine, Kaohsiung Medical University Kaohsiung, Taiwan
| | - C-F Chen
- Department and Graduate Institute of Pharmacology, College of Medicine, Kaohsiung Medical University Kaohsiung, Taiwan
| | - Y-R Hong
- Graduate Institute of Biochemistry, College of Medicine, Kaohsiung Medical University Kaohsiung, Taiwan
| | - S-L Howng
- Department of Neurosurgery, Kaohsiung Medical University Hospital Kaohsiung, Taiwan
| | - Y-L Lin
- Department and Graduate Institute of Pharmacology, College of Medicine, Kaohsiung Medical University Kaohsiung, Taiwan
| | - I-J Chen
- Department and Graduate Institute of Pharmacology, College of Medicine, Kaohsiung Medical University Kaohsiung, Taiwan
- Author for correspondence:
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Shiraishi K, Ascoli M. A co-culture system reveals the involvement of intercellular pathways as mediators of the lutropin receptor (LHR)-stimulated ERK1/2 phosphorylation in Leydig cells. Exp Cell Res 2007; 314:25-37. [PMID: 17727840 PMCID: PMC2180420 DOI: 10.1016/j.yexcr.2007.06.025] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Revised: 06/22/2007] [Accepted: 06/22/2007] [Indexed: 10/23/2022]
Abstract
Co-cultures of lutropin receptor (LHR) positive and negative Leydig cells were used to test the hypothesis that the LHR provokes phosphorylation of the extracellular regulated kinases (ERK1/2) using intracellular and intercellular pathways. Addition of hCG to MA-10 cells (LHR positive) stimulates phosphorylation of the EGF receptor (EGFR) and ERK1/2 whereas addition of hCG to I-10 cells (LHR negative) does not. Addition of hCG to co-cultures of MA-10 and I-10 cells rapidly stimulates the phosphorylation of the EGFR and ERK1/2 in I-10 cells, however. Transfection of interfering constructs shows that the LHR-mediated activation of Fyn in MA-10 cells is necessary for the phosphorylation of the EGFR and ERK1/2 in I-10 cells. This pathway can also be demonstrated in MA-10 cells but the phosphorylation of ERK1/2 in MA-10 cells also involves a second pathway mediated by protein kinase A (PKA). We propose that the LHR-mediated stimulation of the ERK1/2 cascade in Leydig cells depends on two independent pathways. One is intracellular and is mediated by PKA. The second is mediated by Fyn and it involves the release of soluble factors that act to phosphorylate the EGFR in an autocrine/paracrine fashion.
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Affiliation(s)
- Koji Shiraishi
- Department of Pharmacology, Carver College of Medicine, The University of Iowa, Iowa City, IA 52242, USA
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31
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Molinuevo MS, Cortizo AM, Etcheverry SB. Vanadium(IV) complexes inhibit adhesion, migration and colony formation of UMR106 osteosarcoma cells. Cancer Chemother Pharmacol 2007; 61:767-73. [PMID: 17576559 DOI: 10.1007/s00280-007-0532-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2006] [Accepted: 05/05/2007] [Indexed: 11/28/2022]
Abstract
Vanadium is a trace element widely distributed in the environment. In vertebrates it is mainly stored in bone tissue. The unique cellular environment in the bone and the variety of interactions that mediate cancer metastasis determine that certain types of cancer, such as breast and prostate cancer, preferentially metastize in the skeleton. Since this effect usually signifies serious morbidity and grave prognosis there is an increasing interest in the development of new treatments for this pathology. The present work shows that vanadium complexes can inhibit some parameters related to cancer metastasis such as cell adhesion, migration and clonogenicity. We have also investigated the role of protein kinase A in these processes.
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Affiliation(s)
- María S Molinuevo
- Cátedra de Bioquímica Patológica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 47 y 115, 1900, La Plata, Argentina
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Yazawa K, Wang JW, Hao LY, Onoue Y, Kameyama M. Verrucotoxin, a stonefish venom, modulates calcium channel activity in guinea-pig ventricular myocytes. Br J Pharmacol 2007; 151:1198-203. [PMID: 17572694 PMCID: PMC2189832 DOI: 10.1038/sj.bjp.0707340] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND AND PURPOSE Stonefish (Synanceia genus) are commonly found in shallow waters of the Pacific and Indian Oceans. The venom of stonefish is stored in the dorsal fine spines and contains a proteinaceous toxin, verrucotoxin (VTX). The stings produced by the spines induce intense pain, respiratory weakness, damage to the cardiovascular system, convulsions and paralysis, sometimes leading to death. Although there are many studies on VTX, the mechanism(s) underlying the VTX-mediated cardiotoxicity is not yet fully understood. The aim of this study was to investigate the modulation of ion channels in cardiac tissue by VTX. EXPERIMENTAL APPROACH The effects of VTX on changes in the voltage or current in guinea-pig ventricular myocytes were investigated using a patch clamp method. KEY RESULTS VTX (10 microg ml(-1)) prolonged the action potential duration by 2.5-fold. VTX increased L-type Ca(2+) currents (I (Ca(L))) in a concentration-dependent manner with a EC(50) value of 7 microg ml(-1) and a maximum increase of 3.1-fold. The non-selective beta-adrenoceptor antagonist, propranolol (1 microM) and the selective beta(1)-adrenoceptor antagonist, CGP20712A (10 microM) each abolished the effect of VTX (100 microg ml(-1)) on I (Ca(L)). Furthermore, the protein kinase A (PKA) antagonists H-89 (10 microM) and Rp-8-Br-cAMPS (30 microM) inhibited the effect of VTX on I (Ca(L)). CONCLUSIONS AND IMPLICATIONS VTX modulates Ca(2+) channel activity through the beta-adrenoceptor-cAMP-PKA pathway.
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Affiliation(s)
- K Yazawa
- Department of Physiology, Graduate School of Medicine and Dental Science, Kagoshima University Kagoshima, Japan
- Author for correspondence:
| | - J-W Wang
- Department of Physiology, Graduate School of Medicine and Dental Science, Kagoshima University Kagoshima, Japan
| | - L-Y Hao
- Department of Physiology, Graduate School of Medicine and Dental Science, Kagoshima University Kagoshima, Japan
- Department of Pharmacology and Toxicology, School of Pharmaceutical Sciences, China Medical University Shenyang, China
| | - Y Onoue
- Laboratory of Aquatic Resource Science, Faculty of Fisheries, Kagoshima University Kagoshima, Japan
| | - M Kameyama
- Department of Physiology, Graduate School of Medicine and Dental Science, Kagoshima University Kagoshima, Japan
- Author for correspondence:
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Abstract
The activity of light-activatable ("caged") compounds can be temporally and spatially controlled, thereby providing a means to interrogate intracellular biochemical pathways as a function of time and space. Nearly all caged peptides contain photocleavable groups positioned on the side chains of key residues. We describe an alternative active site targeted strategy that disrupts the interaction between the protein target (SH2 domain, kinase, and proteinase) and a critical amide NH moiety of the peptide probe.
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Einicker-Lamas M, Nascimento MTC, Masuda CA, Oliveira MM, Caruso-Neves C. Trypanosoma cruzi epimastigotes: regulation of myo-inositol transport by effectors of protein kinases A and C. Exp Parasitol 2007; 117:171-7. [PMID: 17586497 DOI: 10.1016/j.exppara.2007.04.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Revised: 04/11/2007] [Accepted: 04/23/2007] [Indexed: 01/10/2023]
Abstract
Inositol is the precursor for most Trypanosoma cruzi surface molecules, including phosphoinositides, glycosylinositolphospholipids and glycosylphosphatidylinositol anchors. As the parasite is an inositol auxotroph, the inositol transport system might be a potential target for new trypanocide drugs, as some of its properties are different from its mammalian counterpart. Here, we investigated the modulation exerted by effectors of PKA and PKC on this transport system to comply with the parasite physiology. Pre-incubation of the cells with either dibutyryl-cyclic AMP (25 microM) or forskolin (30 microM) decreased the myo-inositol uptake by half, this effect being reversed by KT5720 (PKA inhibitor). Conversely, pre-incubation of the cells with PMA (2.8 microg/ml) or serum (5%) had a approximately 50% stimulation in myo-inositol uptake, being this effect reversed by staurosporine (0.5 microM) or sphingosine (10 microM). These results allow us to conclude that the myo-inositol transport system in T. cruzi epimastigotes is inhibited by PKA and stimulated by PKC effectors.
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Affiliation(s)
- Marcelo Einicker-Lamas
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, Brazil
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Abstract
The sympathetic nervous system, via norepinephrine, regulates renal sodium transport, and chronic sympathetic activation causes sustained increases in blood pressure by reducing sodium excretion. Our previous studies show that chronic norepinephrine infusion increases the abundance of the bumetanide-sensitive cotransporter type 1, the apical sodium transporter of the thick ascending limb of Henle's loop. The present study was initiated to elucidate the mechanisms by which norepinephrine regulates the protein levels of this transporter in an immortalized thick ascending limb epithelial cell line. Treatment with norepinephrine, either alone or in the presence of actinomycin D or cycloheximide, had no effect on cotransporter mRNA levels. Treatment with norepinephrine, however, increased bumetanide-sensitive cotransporter type 1 protein levels (70% increase versus control; P=0.012), and pretreatment with cycloheximide blocked the effect of norepinephrine on bumetanide-sensitive cotransporter type 1 protein levels. To further elucidate the mechanism, thick ascending limb cells were treated with norepinephrine in the presence of phentolamine (alpha-adrenoceptor blocker), propranolol (beta-adrenoceptor blocker), SQ22536 (adenylyl cyclase inhibitor), PD098059 (mitogen-activated protein kinase pathway inhibitor), H-89 (protein kinase A inhibitor), or staurosporine (protein kinase C inhibitor). Treatment with propranolol, SQ22536, and H-89 abolished the effects of norepinephrine on bumetanide-sensitive cotransporter type 1 protein levels, whereas staurosporine had no effect. Treatment with PD098059 partially inhibited the effects of norepinephrine (40% decrease versus norepinephrine; P=0.03), and treatment with phentolamine potentiated the effects of norepinephrine (30% increase versus norepinephrine; P=0.02) on bumetanide-sensitive cotransporter type 1 protein levels. We conclude that regulation of bumetanide-sensitive cotransporter type 1 by norepinephrine proceeds via the beta-adrenoceptor receptor-cAMP-protein kinase A pathway that involves in part mitogen-activated protein kinases and that alpha-adrenoceptor activation negatively regulates bumetanide-sensitive cotransporter type 1 protein levels.
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MESH Headings
- 8-Bromo Cyclic Adenosine Monophosphate/pharmacology
- Animals
- Bumetanide/pharmacology
- Cell Line
- Colforsin/pharmacology
- Cyclic AMP/physiology
- Cyclic AMP-Dependent Protein Kinases/drug effects
- Cyclic AMP-Dependent Protein Kinases/physiology
- Gene Expression Regulation/drug effects
- Gene Expression Regulation/physiology
- Loop of Henle/cytology
- Loop of Henle/metabolism
- Mice
- Mice, Transgenic
- Mitogen-Activated Protein Kinases/physiology
- Norepinephrine/physiology
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Adrenergic, alpha/drug effects
- Receptors, Adrenergic, alpha/physiology
- Receptors, Adrenergic, beta/drug effects
- Receptors, Adrenergic, beta/physiology
- Sodium Potassium Chloride Symporter Inhibitors/pharmacology
- Sodium-Potassium-Chloride Symporters/metabolism
- Solute Carrier Family 12, Member 1
- Vasopressins/pharmacology
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Affiliation(s)
- Prajakta A Sonalker
- Department of Pharmacology, Center for Clinical Pharmacology, University of Pittsburgh, School of Medicine, PA 15219, USA
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Shi XZ, Choudhury BK, Pasricha PJ, Sarna SK. A novel role of VIP in colonic motility function: induction of excitation-transcription coupling in smooth muscle cells. Gastroenterology 2007; 132:1388-400. [PMID: 17408637 DOI: 10.1053/j.gastro.2007.02.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2006] [Accepted: 01/04/2007] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Vasoactive intestinal polypeptide (VIP) relaxes smooth muscle by generation of cAMP and activation of protein kinase A (PKA). However, PKA activation also phosphorylates the transcription factor CREB. The aim of this study was to investigate whether the phosphorylation of CREB induces gene expression of the pore-forming alpha(1C) subunit of Ca(v)1.2 channels (L-type calcium channels), whose promoter has 2 binding sites for CREB. METHODS The experiments were performed on primary cultures of human colonic circular smooth muscle cells and freshly obtained human and rat colonic circular muscle strips. RESULTS The incubation of human colonic circular smooth muscle cells or muscle strips with VIP for 24 hours enhanced the expression of alpha(1C) protein and mRNA as well as the contractile response to acetylcholine and KCl. On the contrary, incubation of the muscle strips with VIP antagonist for 24 hours suppressed cell contractility. The incubation of the cells with VIP caused sustained generation of cAMP for 24 hours, but PKA activation and CREB phosphorylation were transient. The inhibition of PKA by H-89 or silencing of CREB gene with targeted RNAi blocked the transcription of alpha(1C). Progressive 5' deletions of halpha(1C)1b promoter and site-directed mutations of the 2 CREB binding cis-elements indicated that most of alpha(1C) transcription was mediated by the 5' cAMP response element. CONCLUSIONS The excitation-transcription coupling stimulated by VIP induces expression of the Ca(v)1.2 channels. The influx of calcium through these channels is a critical step in excitation-contraction coupling in smooth muscle cells.
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MESH Headings
- Acetylcholine/pharmacology
- Animals
- Blotting, Western
- CREB-Binding Protein/genetics
- CREB-Binding Protein/metabolism
- Calcium Channels, L-Type/drug effects
- Calcium Channels, L-Type/genetics
- Calcium Channels, L-Type/metabolism
- Cholinergic Agents/pharmacology
- Colon, Sigmoid/cytology
- Colon, Sigmoid/innervation
- Colon, Sigmoid/physiology
- Cyclic AMP-Dependent Protein Kinases/drug effects
- Cyclic AMP-Dependent Protein Kinases/metabolism
- Enzyme Activation
- Gastrointestinal Motility/physiology
- Humans
- Isoquinolines/pharmacology
- Motor Neurons/metabolism
- Muscle Relaxation/physiology
- Muscle, Smooth/drug effects
- Muscle, Smooth/innervation
- Muscle, Smooth/physiology
- Mutation
- Phosphorylation
- Polymerase Chain Reaction
- Potassium Chloride/pharmacology
- Promoter Regions, Genetic
- Protein Kinase Inhibitors/pharmacology
- RNA/genetics
- Rats
- Sulfonamides/pharmacology
- Transcriptional Activation
- Vasoactive Intestinal Peptide/drug effects
- Vasoactive Intestinal Peptide/metabolism
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Affiliation(s)
- Xuan-Zheng Shi
- Department of Internal Medicine, Enteric Neuromuscular Disorders and Visceral Pain Center, Division of Gastroenterology, The University of Texas Medical Branch at Galveston, Galveston, Texas 77555, USA
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Lynch WJ, Kiraly DD, Caldarone BJ, Picciotto MR, Taylor JR. Effect of cocaine self-administration on striatal PKA-regulated signaling in male and female rats. Psychopharmacology (Berl) 2007; 191:263-71. [PMID: 17180335 DOI: 10.1007/s00213-006-0656-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2006] [Accepted: 11/21/2006] [Indexed: 10/23/2022]
Abstract
RATIONALE Chronic cocaine produces changes in the dopamine (DA)/D1/cAMP/protein kinase A (PKA)-regulated signaling pathway that may underlie the development of addiction. OBJECTIVE Given sex differences in the progression to cocaine addiction, we examined the possibility that the PKA pathway is differentially activated by cocaine in male and female rats. MATERIALS AND METHODS Rats were given 24-h access to cocaine (1.5 mg/kg) or saline for 7 days under a discrete trial procedure (four trials per hour). Rats were then retested on responding for cocaine under a progressive-ratio schedule after either 0 (no-delay retest) or 10 (10-day-delay retest) days of abstinence. Markers of PKA-regulated signaling in the striatum and nucleus accumbens were evaluated by Western blotting, including phosphorylation of DA and cAMP-regulated phosphoprotein of 32 kDa (DARPP-32) at Thr 34 and glutamate receptor 1 (GluR1) at Ser 845. RESULTS Compared to males, females had higher levels of DARPP-32 phosphorylated at the PKA site in the striatum. Increased phosphorylation of DARPP-32 at the PKA site was also seen in the nucleus accumbens of females compared to males, particularly among controls and rats tested after a 10-day abstinence period. DARPP-32 phosphorylation was also increased as a consequence of cocaine when tested after a 0-day abstinence period in male rats but not female rats. CONCLUSION These findings indicate sex differences in PKA-regulated signaling in drug-naïve controls. Furthermore, these data suggest that regulation of PKA signaling by cocaine is differentially influenced in male and female rats as a consequence of cocaine exposure and cocaine abstinence period.
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Affiliation(s)
- Wendy J Lynch
- Division of Molecular Psychiatry and Center for Genes and Behavior, Department of Psychiatry, Yale University School of Medicine and Connecticut Mental Health Center, 34 Park Street, New Haven, CT 06508, USA.
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Brock M, Nickel AC, Madziar B, Blusztajn JK, Berse B. Differential regulation of the high affinity choline transporter and the cholinergic locus by cAMP signaling pathways. Brain Res 2007; 1145:1-10. [PMID: 17320829 PMCID: PMC1911187 DOI: 10.1016/j.brainres.2007.01.119] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2006] [Revised: 01/25/2007] [Accepted: 01/26/2007] [Indexed: 12/20/2022]
Abstract
Synthesis, storage and release of acetylcholine (ACh) require the expression of several specialized enzymes, including choline acetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT) and the high-affinity choline transporter (CHT). Extracellular factors that regulate CHT expression and their signaling pathways remain poorly characterized. Using the NSC-19 cholinergic cell line, derived from embryonic spinal cord, we compared the effects of the second messenger cAMP on the expression of CHT and the cholinergic locus containing the ChAT and VAChT genes. Treatment of NSC-19 cells with dbcAMP and forskolin, thus increasing intracellular cAMP levels, significantly reduced CHT mRNA expression, while it upregulated ChAT/VAChT mRNA levels and ChAT activity. The cAMP-induced CHT downregulation was independent of PKA activity, as shown in treatments with the PKA inhibitor H-89. The alternative Epac-Rap pathway, when stimulated by a specific Epac activator, led to significant downregulation of CHT and ChAT, and, to a lesser extent, VAChT. In contrast, the PKA activator 6-BNZ-cAMP stimulated the expression of all three genes, but with varying concentration-dependence profiles. Our results indicate that elevations of intraneuronal cAMP concentration have differential effects on the cholinergic phenotype, depending on the involvement of different downstream effectors. Interestingly, although CHT is expressed predominantly in cholinergic cells, its regulation appears to be distinct from that of the cholinergic locus.
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Affiliation(s)
- Martina Brock
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, 715 Albany Street, Room L-808C, Boston, MA 02118, USA
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Abstract
In cerebellar granule cells, the mitogen-activated protein kinase (MAPK) or extracellular signal-regulated kinase (ERK) cascade mediates multiple functions, including proliferation, differentiation, and survival. In these cells, ERKs are activated by diverse stimuli, including cyclic adenosine monophosphate (cAMP), pituitary adenylate cyclase activating protein (PACAP), depolarization induced by elevated extracellular potassium (KCl), and the neurotrophin brain-derived neurotrophic factor. Extensive studies in neuronal cell lines have implicated the small G proteins Ras and Rap1 in the activation of ERKs by cAMP, PACAP, and KCl. However, the requirement of Ras and Rap1 in these pathways in cerebellar granule cells has not been addressed. In this study, we utilize multiple biochemical assays to determine the mechanisms of action and requirement of Ras and Rap1 in cultured cerebellar granule cells. We show that both Ras and Rap1 can be activated by cAMP or PACAP via protein kinase (PKA)-dependent mechanisms. KCl activation of Ras also required PKA. Using both adenoviral and transgenic approaches, we show that Ras plays a major role in ERK activation by cAMP, PACAP, and KCl, while Rap1 also mediates activation of a selective membrane-associated pool of ERKs. Furthermore, Rap1, but not Ras, activation by PKA appears to require the action of Src family kinases.
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Affiliation(s)
- Yutaro Obara
- Vollum Institute, L474, Oregon Health and Science University, Portland, Oregon 97239, USA
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40
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De Petrocellis L, Starowicz K, Moriello AS, Vivese M, Orlando P, Di Marzo V. Regulation of transient receptor potential channels of melastatin type 8 (TRPM8): effect of cAMP, cannabinoid CB(1) receptors and endovanilloids. Exp Cell Res 2007; 313:1911-20. [PMID: 17428469 DOI: 10.1016/j.yexcr.2007.01.008] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Revised: 01/09/2007] [Accepted: 01/10/2007] [Indexed: 11/17/2022]
Abstract
The transient receptor potential channel of melastatin type 8 (TRPM8), which is gated by low (<25 degrees C) temperature and chemical compounds, is regulated by protein kinase C-mediated phosphorylation in a way opposite to that observed with the transient receptor potential channel of vanilloid type 1 (TRPV1), i.e. by being desensitized and not sensitized. As TRPV1 is sensitized also by protein kinase A (PKA)-mediated phosphorylation, we investigated the effect of two activators of the PKA pathway, 8-Br-cAMP and forskolin, on the activity of menthol and icilin at TRPM8 in HEK-293 cells stably overexpressing the channel (TRPM8-HEK-293 cells). We also studied the effect on TRPM8 of: (1) a series of compounds previously shown to activate or antagonize TRPV1, and (2) co-stimulation of transiently co-expressed cannabinoid CB(1) receptors. Both 8-Br-cAMP (100 microM) and forskolin (10 microM) right-shifted the dose-response curves for the TRPM8-mediated effect of icilin and menthol on intracellular Ca(2+). The inhibitory effects of 8-Br-cAMP and forskolin were attenuated by the selective PKA inhibitor Rp-cAMP-S. Stimulation of human CB(1) receptors transiently co-expressed in TRPM8-HEK-293 cells also inhibited TRPM8 response to icilin. Finally, some TRPV1 agonists and antagonists, but not iodinated antagonists, antagonized icilin- and much less so menthol-, induced TRPM8 activation. Importantly, the endovanilloids/endocannabinoids, anandamide and NADA, also antagonized TRPM8 at submicromolar concentrations. Although these findings need to be confirmed by experiments directly measuring TRPM8 activity in natively TRPM8-expressing cells, they support the notion that the same regulatory events have opposing actions on TRPM8 and TRPV1 receptors and identify anandamide and NADA as the first potential endogenous functional antagonists of TRPM8 channels.
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Affiliation(s)
- Luciano De Petrocellis
- Endocannabinoid Research Group, Institute of Cybernetics, National Research Council, Via Campi Flegrei 34, Comprensorio Olivetti, 80078 Pozzuoli, Naples, Italy
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41
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Affiliation(s)
- Mark R Cookson
- Laboratory of Neurogenetics, National Institute on Aging, Bethesda, MD, USA
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42
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Coitinho AS, Freitas ARO, Lopes MH, Hajj GNM, Roesler R, Walz R, Rossato JI, Cammarota M, Izquierdo I, Martins VR, Brentani RR. The interaction between prion protein and laminin modulates memory consolidation. Eur J Neurosci 2006; 24:3255-64. [PMID: 17156386 DOI: 10.1111/j.1460-9568.2006.05156.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Cellular prion protein (PrPc) has a pivotal role in prion diseases. PrPc is a specific receptor for laminin (LN) gamma1 peptide and several lines of evidence indicate that it is also involved in neural plasticity. Here we investigated whether the interaction between PrPc and LN plays a role in rat memory formation. We found that post-training intrahippocampal infusion of PrPc-derived peptides that contain the LN binding site (PrPc163-182 and PrPc173-192) or of anti-PrPc or anti-LN antibodies that inhibit PrPc-LN interaction impaired inhibitory avoidance memory retention. The amnesic effect of anti-PrPc antibodies and PrPc173-192 peptide was reversed by co-infusion of a LN gamma1 chain-derived peptide containing the PrPc-binding site, suggesting that PrPc-LN interaction is indeed crucial for memory consolidation. In addition, PrPc173-192 peptide and anti-PrPc or anti-LN antibodies also inhibited the activation of hippocampal cAMP-dependent protein kinase A (PKA) and extracellular regulated kinase (ERK1/2), two kinases that mediate the up-regulation of signaling pathways needed for consolidation of inhibitory avoidance memory. Our findings show that, through its interaction with LN, hippocampal PrPc plays a critical role in memory processing and suggest that this role is mediated by activation of both PKA and ERK1/2 signaling pathways.
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Affiliation(s)
- Adriana S Coitinho
- Centro Universitário Feevale, Instituto de Ciências da Saúde, RS 239, 2755, 93352-000, Novo Hamburgo, RS, and Centro de Cirurgia de Epilepsia do Estado de Santa Catarina, Hospital Governador Celso Ramos, SC, Brazil
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Lanuza MA, Gizaw R, Viloria A, González CM, Besalduch N, Dunlap V, Tomàs J, Nelson PG. Phosphorylation of the nicotinic acetylcholine receptor in myotube-cholinergic neuron cocultures. J Neurosci Res 2006; 83:1407-14. [PMID: 16555299 DOI: 10.1002/jnr.20848] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Acetylcholine receptor (AChR) stability in the postsynaptic membrane is affected by serine kinases. AChR are phosphorylated by protein kinase C (PKC) and PKA, and we have shown that activation of PKA and PKC have opposite effects on AChR stability and that this may play some role in the selective, activity-dependent synapse loss that occurs during development of the neuromuscular junction. Myotube cultures with and without added spinal motor neurons were probed with immunoaffinity-purified antibodies prepared against phosphorylated peptides with amino acid sequences from different AChR subunits. Different treatments activating PKC (phorbol 12-myristate 13-acetate; PMA) or PKA (dibutyryl cyclic adenosine monophosphate; cAMP) or blocking electrical activity (tetrodotoxin; TTX) of the cocultures were chosen because of their known effects, direct or indirect, on receptor stability. We asked whether the phospho-specific antibody staining in conjunction with alpha-bungarotoxin (BTX) identification of AChR aggregates could provide a direct demonstration of changes in receptor phosphorylation produced by the treatments. We found that PMA treatment did increase phosphorylation of the delta subunit and cAMP increased phosphorylation of the epsilon subunit relative to total BTX labeling in muscle-nerve cocultures, but not in muscle-only cultures. Blockade of electrical activity with TTX increased the incidence of aggregates that showed no phospho-epsilon staining. Myotube cultures grown in the absence of neurons did not show the responses of myotubes in cocultures. The results show that manipulations that alter receptor stability also produce changes in receptor phosphorylation. We suggest that phosphorylation may be a mechanism mediating the changes in receptor stability.
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Affiliation(s)
- Maria A Lanuza
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Reus, Spain.
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44
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Elliott MK, Sisson JH, West WW, Wyatt TA. Differential in vivo effects of whole cigarette smoke exposure versus cigarette smoke extract on mouse ciliated tracheal epithelium. Exp Lung Res 2006; 32:99-118. [PMID: 16754475 PMCID: PMC2092449 DOI: 10.1080/01902140600710546] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
In this study the authors compared the affect of vapor phase cigarette smoke (CS) versus cigarette smoke extract (CSE) on the lungs and upper airway of C57BL/6 mice. The authors found that CSE treatment significantly increased neutrophil influx (P < .001), baseline ciliary beat frequency (CBF) (P < .05), and protein kinase C activity compared to CS and controls. Isoproterenol increased CBF with CS exposure, but decreased CBF with CSE (P < .01). Isoproterenol increased protein kinase A (PKA) activity in all groups except CSE. CSE exposure induced inflammatory cell bronchiolitis. These data indicate that CSE exposure has differential effects on the lungs and tracheal epithelium compared to CS exposure.
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Affiliation(s)
- Margaret K Elliott
- Pulmonary, Critical Care and Sleep Medicine Section, University of Nebraska Medical Center, Omaha, Nebraska 68198-5300, USA
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Taniguchi N, Shinoda Y, Takei N, Nawa H, Ogura A, Tominaga-Yoshino K. Possible involvement of BDNF release in long-lasting synapse formation induced by repetitive PKA activation. Neurosci Lett 2006; 406:38-42. [PMID: 16904263 DOI: 10.1016/j.neulet.2006.06.071] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2006] [Revised: 06/22/2006] [Accepted: 06/25/2006] [Indexed: 11/17/2022]
Abstract
For the analysis of the cellular mechanism underlying long-term synaptic plasticity, a model system that allows long-lasting pursuit is required. Previously we reported that, in hippocampal neurons under dissociated cell culture conditions, repeated (but not a single) transient activation of protein kinase A (PKA) led to an increase in the number of synapses that lasted >3 weeks, and hence we proposed that this phenomenon should serve as an appropriate model system. Here we report that repeated pulsatile application of brain-derived neurotrophic factor (BDNF) leads to persistent synapse formation equivalent to that after the repeated transient activation of PKA. A BDNF-scavenging substance applied concomitantly with PKA activation abolished the synapse formation. The release of BDNF upon PKA activation was confirmed by phosphorylation of TrkB. These results indicate that the release of BDNF is involved in the putative signaling cascade connecting PKA activation and synapse formation.
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Affiliation(s)
- Naoko Taniguchi
- Department of Neuroscience, Osaka University Graduate School of Frontier Biosciences, Machikaneyama-cho 1-1, Toyonaka, Osaka 560-0043, Japan
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Yamada K, Inoue H, Kida S, Masushige S, Nishiyama T, Mishima K, Saito I. Involvement of cAMP response element-binding protein activation in salivary secretion. Pathobiology 2006; 73:1-7. [PMID: 16785762 DOI: 10.1159/000093086] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2005] [Accepted: 03/08/2006] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE Saliva secretion is mediated by cAMP and the calcium signaling pathway in salivary acinar cells. The PKA signaling pathway plays an important role in protein secretion through the activation of cAMP, in fluid secretion through the elevation of intracellular calcium and in the activation of cAMP response element-binding protein (CREB), which is involved in these signaling cascades. In this study, we investigated whether the activation of CREB plays a part in the salivary secretion in mice. METHODS We examined CREB activation by assessing phosphorylation at the serine-133 position using Western blotting. RESULTS Carbachol (a muscarinic acetylcholine agonist) and isoproterenol (a beta-adrenergic agonist) markedly activated CREB in parotid acinar cells. Carbachol and isoproterenol-induced CREB phosphorylation was blocked by atropine (a muscarinic acetylcholine antagonist) and propranolol (a beta-adrenergic antagonist), respectively. The PKA inhibitor H89 inhibited CREB activation, but the PLC inhibitor U73122 did not. Moreover, carbachol- and isoproterenol-stimulated amylase secretion from parotid acinar cells was inhibited by H89 and adenoviral dominant-negative CREB. CONCLUSION These results indicate that the muscarinic and beta-adrenergic activation of CREB was mediated through the PKA pathway and that CREB is involved in protein secretion from parotid acinar cells.
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Affiliation(s)
- Koichi Yamada
- Department of Pathology, Tsurumi University School of Dental Medicine, Yokohama, Japan
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47
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Asyyed A, Storm D, Diamond I. Ethanol activates cAMP response element-mediated gene expression in select regions of the mouse brain. Brain Res 2006; 1106:63-71. [PMID: 16854384 DOI: 10.1016/j.brainres.2006.05.107] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2006] [Revised: 05/19/2006] [Accepted: 05/24/2006] [Indexed: 11/18/2022]
Abstract
UNLABELLED The specific brain regions that contribute to behavioral changes produced by ethanol are not clearly understood. We know that cAMP-PKA signaling has been strongly implicated in the CNS effects of ethanol. Ethanol promotes activation and translocation of the PKA catalytic subunit (Calpha) into the nucleus in cell lines and primary neuronal cultures. PKA Calpha translocation to the nucleus is followed by cAMP Response Element protein phosphorylation (pCREB) and cAMP Response Element (CRE)-mediated gene expression. Here, we use X-gal histochemistry to map CRE-mediated gene transcription in the brain of CRE-lacZ transgenic mice following ethanol injection. RESULTS 3 h after i.p. ethanol injection (3.2 g/kg, 16% wt/vol.), the number of X-gal positive cells was increased in the nucleus accumbens (202 +/- 63 cells/field compared to 71 +/- 47 cells/field in saline injected controls, P < 0.05 by paired t-test, n = 10). Similar increases were found in other mesolimbic areas and brain regions associated with rewarding and addictive responses. These include: prefrontal cortex, lateral and medial septum, basolateral amygdala, paraventricular and anterior hypothalamus, centromedial thalamus, CA1 region of hippocampus and dentate gyrus, substantia nigra pars compacta, ventral tegmental area, geniculate nucleus and the superior colliculus. CONCLUSION these results confirm and extend current concepts that ethanol stimulates cAMP-PKA signaling in brain regions involved in CNS responses to ethanol.
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MESH Headings
- Alcohol-Induced Disorders, Nervous System/genetics
- Alcohol-Induced Disorders, Nervous System/metabolism
- Alcohol-Induced Disorders, Nervous System/physiopathology
- Animals
- Brain/anatomy & histology
- Brain/drug effects
- Brain/metabolism
- Brain Chemistry/drug effects
- Brain Chemistry/genetics
- Central Nervous System Depressants/pharmacology
- Cyclic AMP/metabolism
- Cyclic AMP Response Element-Binding Protein/genetics
- Cyclic AMP-Dependent Protein Kinases/drug effects
- Cyclic AMP-Dependent Protein Kinases/metabolism
- Disease Models, Animal
- Ethanol/pharmacology
- Female
- Galactosides
- Gene Expression Regulation/drug effects
- Gene Expression Regulation/physiology
- Genes, Reporter/drug effects
- Genes, Reporter/physiology
- Indoles
- Lac Operon/drug effects
- Lac Operon/genetics
- Limbic System/anatomy & histology
- Limbic System/drug effects
- Limbic System/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- RNA, Messenger/drug effects
- RNA, Messenger/metabolism
- Reward
- Signal Transduction/drug effects
- Signal Transduction/physiology
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Affiliation(s)
- Asma Asyyed
- Ernest Gallo Clinic and Research Center, Department of Neurology, University of California, San Francisco, 5858 Horton St., Ste. 200, Emeryville, CA 94608, USA.
| | - Daniel Storm
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Ivan Diamond
- Ernest Gallo Clinic and Research Center, Department of Neurology, University of California, San Francisco, 5858 Horton St., Ste. 200, Emeryville, CA 94608, USA; Department of Neuroscience, CV Therapeutics, Palo Alto, CA 94304, USA
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48
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Xue JF, Liu ZJ, Hu JF, Chen H, Zhang JT, Chen NH. Ginsenoside Rb1 promotes neurotransmitter release by modulating phosphorylation of synapsins through a cAMP-dependent protein kinase pathway. Brain Res 2006; 1106:91-98. [PMID: 16836988 DOI: 10.1016/j.brainres.2006.05.106] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2006] [Revised: 05/24/2006] [Accepted: 05/26/2006] [Indexed: 11/16/2022]
Abstract
Ginseng, the root of Panax ginseng C.A. Meyer (Araliaceae), has been extensively used in traditional oriental medicine for the prevention and treatment of aging-related disorders for over 2000 years. Accumulating evidence suggests that ginsenosides such as Rg1 and Rb1, which are the pharmacologically active ingredients of ginseng, modulate neurotransmission. Synapsins are abundant phosphoproteins essential for regulating neurotransmitter release. All synapsins contain a short amino-terminal domain A that is highly conserved and phosphorylated by cAMP-dependent protein kinase (PKA), which plays a key role in regulating neurotransmitter release. In the present study, we demonstrated that both Rg1 and Rb1 increased neurotransmitter release in undifferentiated and differentiated PC12 cells. However, in the presence of the PKA inhibitor H89, Rg1, but not Rb1, still induced neurotransmitter release. Moreover, Rb1, but not Rg1, enhanced the phosphorylation of synapsins via PKA pathway. In summary, Rb1 promotes neurotransmitter release by increasing the phosphorylation of synapsins through the PKA pathway, whereas the similar effects observed with Rg1 are independent of the phosphorylation of synapsins.
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Affiliation(s)
- Jian-Fei Xue
- Institute of Material Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, PR China; Medical College of Chinese People's Armed Police Force, Tianjin 300162, PR China
| | - Zhi-Jun Liu
- Institute of Material Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, PR China
| | - Jin-Feng Hu
- Institute of Material Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, PR China
| | - Hong Chen
- Medical College of Chinese People's Armed Police Force, Tianjin 300162, PR China
| | - Jun-Tian Zhang
- Institute of Material Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, PR China
| | - Nai-Hong Chen
- Institute of Material Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, PR China.
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49
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Witkowski G, Szulczyk P. Opioid mu receptor activation inhibits sodium currents in prefrontal cortical neurons via a protein kinase A- and C-dependent mechanism. Brain Res 2006; 1094:92-106. [PMID: 16733049 DOI: 10.1016/j.brainres.2006.03.119] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2005] [Revised: 03/28/2006] [Accepted: 03/30/2006] [Indexed: 11/18/2022]
Abstract
Opioid transmission in the medial prefrontal cortex is involved in mood regulation and is altered by drug dependency. However, the mechanism by which ionic channels in cortical neurons are controlled by mu opioid receptors has not been elucidated. In this study, the effect of mu opioid receptor activation on voltage-dependent Na(+) currents was assessed in medial prefrontal cortical neurons. In 66 out of 98 nonpyramidal neurons, the application of 1 microM of DAMGO ([D-Ala(2), N-Me-Phe(4), Gly(5)-OL]-enkephalin), a specific mu receptor agonist, caused a decrease in the Na(+) current amplitude to approximately 79% of that observed in controls (half blocking concentration = 0.094 microM). Moreover, DAMGO decreased the maximum current activation rate, prolonged its time-dependent inactivation, and shifted the half inactivation voltage from -63.4 mV to -71.5 mV. DAMGO prolonged the time constant of recovery from inactivation from 5.4 ms to 7.4 ms. The DAMGO-evoked inhibition of Na(+) current was attenuated when GDP-beta-S (0.4 mM, Guanosine 5-[beta-thio]diphosphate trilithium salt) was included in the intracellular solution. Inhibitors of kinase A and C greatly attenuated the DAMGO-induced inhibition, while adenylyl cyclase and kinase C activators mirrored the DAMGO inhibitory effect. Na(+) currents in pyramidal neurons were insensitive to DAMGO. We conclude that the activation of mu opioid receptors inhibits the voltage-dependent Na(+) currents expressed in nonpyramidal neurons of the medial prefrontal cortex, and that kinases A and C are involved in this inhibitory pathway.
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Affiliation(s)
- Grzegorz Witkowski
- Postgraduate School of Molecular Medicine, Pasteura 3, Warsaw 02 093, Poland
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50
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Santschi LA, Zhang XL, Stanton PK. Activation of receptors negatively coupled to adenylate cyclase is required for induction of long-term synaptic depression at Schaffer collateral-CA1 synapses. ACTA ACUST UNITED AC 2006; 66:205-19. [PMID: 16329119 DOI: 10.1002/neu.20213] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Chemical LTD (CLTD) of synaptic transmission is triggered by simultaneously increasing presynaptic [cGMP] while inhibiting PKA. Here, we supply evidence that class II, but not III, metabotropic glutamate receptors (mGluRs), and A1 adenosine receptors, both negatively coupled to adenylate cyclase, play physiologic roles in providing PKA inhibition necessary to promote the induction of LTD at Schaffer collateral-CA1 synapses in hippocampal slices. Simultaneous activation of group II mGluRs with the selective agonist (2S,2'R,3'R)-2-(2',3'-dicarboxy-cyclopropyl) glycine (DCGIV; 5 microM), while raising [cGMP] with the type V phosphodiesterase inhibitor, zaprinast (20 microM), resulted in a long-lasting depression of synaptic strength. When zaprinast (20 microM) was combined with a cell-permeant PKA inhibitor H-89 (10 microM), the need for mGluR IIs was bypassed. DCGIV, when combined with a "submaximal" low frequency stimulation (1 Hz/400 s), produced a saturating LTD. The mGluR II selective antagonist, (2S)-alpha-ethylglutamic acid (EGLU; 5 microM), blocked induction of LTD by prolonged low frequency stimulation (1 Hz/900 s). In contrast, the mGluR III selective receptor blocker, (RS)-a-Cyclopropyl-[3- 3H]-4-phosphonophenylglycine (CPPG; 10 microM), did not impair LTD. The selective adenosine A1 receptor antagonist, 1,3-dipropyl-8-cyclopentylxanthine (DPCPX; 100 nM), also blocked induction of LTD, while the adenosine A1 receptor agonist N6-cyclohexyl adenosine (CHA; 50 nM) significantly enhanced the magnitude of LTD induced by submaximal LFS and, when paired with zaprinast (20 microM), was sufficient to elicit CLTD. Inhibition of PKA with H-89 rescued the expression of LTD in the presence of either EGLU or DPCPX, confirming the hypothesis that both group II mGluRs and A1 adenosine receptors enhance the induction of LTD by inhibiting adenylate cyclase and reducing PKA activity.
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Affiliation(s)
- Linda A Santschi
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
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