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Mikheil D, Larsen MA, Hsiao K, Murray NH, Ugo T, Wang H, Goueli SA. A bioluminescent and homogeneous assay for monitoring GPCR-mediated cAMP modulation and PDE activity. Sci Rep 2024; 14:4440. [PMID: 38396287 PMCID: PMC10891162 DOI: 10.1038/s41598-024-55038-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 02/20/2024] [Indexed: 02/25/2024] Open
Abstract
3',5'-Cyclic adenosine monophosphate (cAMP), the first identified second messenger, is implicated in diverse cellular processes involving cellular metabolism, cell proliferation and differentiation, apoptosis, and gene expression. cAMP is synthesized by adenylyl cyclase (AC), which converts ATP to cAMP upon activation of Gαs-protein coupled receptors (GPCRs) in most cases and hydrolyzed by cyclic nucleotide phosphodiesterases (PDEs) to 5'-AMP. Dysregulation of cAMP signaling is implicated in a wide range of pathophysiological conditions such as cardiovascular diseases, neurodegenerative and behavioral disorders, cancers, diabetes, obesity, cataracts, and others. Therefore, cAMP targeted therapies have been and are still undergoing intense investigation for the treatment of these and other diseases. This highlights the need for developing assays to detect and monitor cAMP levels. In this study, we show cAMP Lumit assay as a highly specific homogeneous bioluminescent assay suitable for high throughput screenings with a large assay window and a wide dynamic range for cAMP detection. We believe that this assay will aid and simplify drug discovery screening efforts for cAMP signaling targeted therapies.
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Affiliation(s)
- Dareen Mikheil
- Promega Corporation, 2800 Woods Hollow Road, Madison, WI, 53711, USA
| | - Matthew A Larsen
- Promega Biosciences, 277 Granada Drive, San Luis Obispo, CA, 93401, USA
| | - Kevin Hsiao
- Promega Corporation, 2800 Woods Hollow Road, Madison, WI, 53711, USA
| | - Nathan H Murray
- Promega Corporation, 2800 Woods Hollow Road, Madison, WI, 53711, USA
| | - Tim Ugo
- Promega Biosciences, 277 Granada Drive, San Luis Obispo, CA, 93401, USA
| | - Hui Wang
- Promega Biosciences, 277 Granada Drive, San Luis Obispo, CA, 93401, USA
| | - Said A Goueli
- Promega Corporation, 2800 Woods Hollow Road, Madison, WI, 53711, USA.
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Du Y, Tong Y, Quan Y, Wang G, Cheng H, Gu S, Jiang JX. Protein kinase A activation alleviates cataract formation via increased gap junction intercellular communication. iScience 2023; 26:106114. [PMID: 36852280 PMCID: PMC9958365 DOI: 10.1016/j.isci.2023.106114] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 12/09/2022] [Accepted: 01/28/2023] [Indexed: 02/05/2023] Open
Abstract
Cataract is the leading cause of blindness worldwide. Here, we reported a potential, effective therapeutic mean for cataract prevention and treatment. Gap junction communication, an important mechanism in maintaining lens transparency, is increased by protein kinase A (PKA). We found that PKA activation reduced cataracts induced by oxidative stress, increased gap junctions/hemichannels in connexin (Cx) 50, Cx46 or Cx50 and Cx46 co-expressing cells, and decreased reactive oxygen species (ROS) levels. However, ROS reduction was shown in wild-type, Cx46 and Cx50 knockout, but not in Cx46/Cx50 double KO lens. In addition, PKA activation protects lens fiber cell death induced by oxidative stress via hemichannel-mediated glutathione transport. Connexin deletion increased lens opacity induced by oxidative stress associated with reduction of anti-oxidative stress gene expression. Together, our results suggest that PKA activation through increased connexin channels in lens fiber cell decreases ROS levels and cell death, leading to alleviated cataracts.
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Affiliation(s)
- Yu Du
- Department of Ophthalmology, Lanzhou University Second Hospital; Second Clinical School, Lanzhou University, Lanzhou, Gansu, 730000, China
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
| | - Yuxin Tong
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
| | - Yumeng Quan
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
- Department of Ophthalmology, First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Guangyan Wang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
- Department of Ophthalmology, First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Hongyun Cheng
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
| | - Sumin Gu
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
| | - Jean X. Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
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Quan Y, Du Y, Tong Y, Gu S, Jiang JX. Connexin Gap Junctions and Hemichannels in Modulating Lens Redox Homeostasis and Oxidative Stress in Cataractogenesis. Antioxidants (Basel) 2021; 10:1374. [PMID: 34573006 PMCID: PMC8464761 DOI: 10.3390/antiox10091374] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 08/24/2021] [Indexed: 11/18/2022] Open
Abstract
The lens is continuously exposed to oxidative stress insults, such as ultraviolet radiation and other oxidative factors, during the aging process. The lens possesses powerful oxidative stress defense systems to maintain its redox homeostasis, one of which employs connexin channels. Connexins are a family of proteins that form: (1) Hemichannels that mediate the communication between the intracellular and extracellular environments, and (2) gap junction channels that mediate cell-cell communication between adjacent cells. The avascular lens transports nutrition and metabolites through an extensive network of connexin channels, which allows the passage of small molecules, including antioxidants and oxidized wastes. Oxidative stress-induced post-translational modifications of connexins, in turn, regulates gap junction and hemichannel permeability. Recent evidence suggests that dysfunction of connexins gap junction channels and hemichannels may induce cataract formation through impaired redox homeostasis. Here, we review the recent advances in the knowledge of connexin channels in lens redox homeostasis and their response to cataract-related oxidative stress by discussing two major aspects: (1) The role of lens connexins and channels in oxidative stress and cataractogenesis, and (2) the impact and underlying mechanism of oxidative stress in regulating connexin channels.
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Affiliation(s)
| | | | | | | | - Jean X. Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA; (Y.Q.); (Y.D.); (Y.T.); (S.G.)
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Ghorbani A, Jeddi-Tehrani M, Saidpour A, Safa M, Bayat AA, Zand H. PI3K/AKT and Mdm2 activation are associated with inhibitory effect of cAMP increasing agents on DNA damage-induced cell death in human pre-B NALM-6 cells. Arch Biochem Biophys 2014; 566:58-66. [PMID: 25524737 DOI: 10.1016/j.abb.2014.11.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 11/17/2014] [Accepted: 11/21/2014] [Indexed: 11/24/2022]
Abstract
DNA damage response (DDR) consists of both proapoptotic and prosurvival signaling branches. Superiority of each signaling branch determines the outcome of DNA damage: death or allowing the repair. The present authors have previously shown that an increased intracellular level of cAMP disrupts p53-mediated apoptosis in human pre-B NALM-6 cells and inhibition of NF-κB prevents prosurvival effect of cAMP during DNA damage. AKT/PKB (protein kinase B) is a general mediator of survival signaling. AKT signaling inhibits p53-mediated transcription and apoptosis. The results of present study showed that cAMP disrupted DNA damage/p53-mediated apoptosis through AKT and subsequent NF-κB activation. These results suggested that AKT may be found as part of a complex with scaffolding proteins, beta-arrestins and PDE4D. cAMP disarticulated the complex through binding to PDE4D compartment. It seems that release of AKT protein potentiated DDR activated pro-survival AKT in NALM-6 cells. Taken together, the present data indicated that regulation of AKT signaling may determine the fate of cells exposed to genotoxic stress.
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Affiliation(s)
- Arman Ghorbani
- Faculty of Nutrition and Diet Therapy, Department of Cellular and Molecular Nutrition, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahmood Jeddi-Tehrani
- Monoclonal Antibody Research Center, Avicenna Research Institute, ACECR, Tehran, Iran
| | - Atoosa Saidpour
- National Nutrition and Food Technology Research Institute, Faculty of Nutrition Science and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Majid Safa
- Department of Hematology, Cellular and Molecular Research Center, Faculty of Allied Medicine, Iran University of Medical Sciences, Iran
| | - Ahmad Ali Bayat
- Monoclonal Antibody Research Center, Avicenna Research Institute, ACECR, Tehran, Iran
| | - Hamid Zand
- National Nutrition and Food Technology Research Institute, Faculty of Nutrition Science and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Gold MG, Gonen T, Scott JD. Local cAMP signaling in disease at a glance. J Cell Sci 2014; 126:4537-43. [PMID: 24124191 DOI: 10.1242/jcs.133751] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The second messenger cyclic AMP (cAMP) operates in discrete subcellular regions within which proteins that synthesize, break down or respond to the second messenger are precisely organized. A burgeoning knowledge of compartmentalized cAMP signaling is revealing how the local control of signaling enzyme activity impacts upon disease. The aim of this Cell Science at a Glance article and the accompanying poster is to highlight how misregulation of local cyclic AMP signaling can have pathophysiological consequences. We first introduce the core molecular machinery for cAMP signaling, which includes the cAMP-dependent protein kinase (PKA), and then consider the role of A-kinase anchoring proteins (AKAPs) in coordinating different cAMP-responsive proteins. The latter sections illustrate the emerging role of local cAMP signaling in four disease areas: cataracts, cancer, diabetes and cardiovascular diseases.
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Affiliation(s)
- Matthew G Gold
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
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Wang Z, Han J, David LL, Schey KL. Proteomics and phosphoproteomics analysis of human lens fiber cell membranes. Invest Ophthalmol Vis Sci 2013; 54:1135-43. [PMID: 23349431 DOI: 10.1167/iovs.12-11168] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
PURPOSE The human lens fiber cell insoluble membrane fraction contains important membrane proteins, cytoskeletal proteins, and cytosolic proteins that are strongly associated with the membrane. The purpose of this study was to characterize the lens fiber cell membrane proteome and phosphoproteome from human lenses. METHODS HPLC-mass spectrometry-based multidimensional protein identification technology (MudPIT), without or with phosphopeptide enrichment, was applied to study the proteome and phosphoproteome of lens fiber cell membranes, respectively. RESULTS In total, 951 proteins were identified, including 379 integral membrane and membrane-associated proteins. Enriched gene categories and pathways based on the proteomic analysis include carbohydrate metabolism (glycolysis/gluconeogenesis, pentose phosphate pathway, pyruvate metabolism), proteasome, cell-cell signaling and communication (GTP binding, gap junction, focal adhesion), glutathione metabolism, and actin regulation. The combination of TiO(2) phosphopeptide enrichment and MudPIT analysis revealed 855 phosphorylation sites on 271 proteins, including 455 phosphorylation sites that have not been previously identified. PKA, PKC, CKII, p38MAPK, and RSK are predicted as the major kinases for phosphorylation on the sites identified in the human lens membrane fraction. CONCLUSIONS The results presented herein significantly expand the characterized proteome and phosphoproteome of the human lens fiber cell and provide a valuable reference for future research in studies of lens development and disease.
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Affiliation(s)
- Zhen Wang
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
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Abstract
Na,K-ATPase is responsible for maintaining the correct concentrations of sodium and potassium in lens cells. Na,K-ATPase activity is different in the two cell types that make up the lens, epithelial cells and fibers; specific activity in the epithelium is higher than in fibers. In some parts of the fiber mass Na,K-ATPase activity is barely detectable. There is a large body of evidence that suggests Na,K-ATPase-mediated ion transport by the epithelium contributes significantly to the regulation of ionic composition in the entire lens. In some species different Na,K-ATPase isoforms are present in epithelium and fibers but in general, fibers and epithelium express a similar amount of Na,K-ATPase protein. Turnover of Na,K-ATPase by protein synthesis may contribute to preservation of high Na,K-ATPase activity in the epithelium. In ageing lens fibers, oxidation, and glycation may decrease Na,K-ATPase activity. Na,K-ATPase activity in lens fibers and epithelium also may be subject to regulation as the result of protein tyrosine phosphorylation. Moreover, activation of G protein-coupled receptors by agonists such as endothelin-1 elicits changes of Na,K-ATPase activity. The asymmetrical distribution of Na,K-ATPase activity in the epithelium and fibers may contribute to ionic currents that flow in and around the lens. Studies on human cataract and experimental cataract in animals reveal changes of Na,K-ATPase activity but no clear pattern is evident. However, there is a convincing link between abnormal elevation of lens sodium and the opacification of the lens cortex that occurs in age-related human cataract.
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Affiliation(s)
- Nicholas A Delamere
- Department of Ophthalmology and Visual Sciences, School of Medicine, Louisville, Kentucky, USA.
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