1
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Sherpa RT, Moshal KS, Agarwal SR, Ostrom RS, Harvey RD. Role of protein kinase A and A kinase anchoring proteins in buffering and compartmentation of cAMP signalling in human airway smooth muscle cells. Br J Pharmacol 2024; 181:2622-2635. [PMID: 38613158 PMCID: PMC11219259 DOI: 10.1111/bph.16357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 01/24/2024] [Accepted: 02/12/2024] [Indexed: 04/14/2024] Open
Abstract
BACKGROUND AND PURPOSE In human airway smooth muscle (hASM) cells, not all receptors stimulating cAMP production elicit the same effects. This can only be explained if cAMP movement throughout the cell is restricted, yet the mechanisms involved are not fully understood. Phosphodiesterases (PDEs) contribute to compartmentation of many cAMP responses, but PDE activity alone is predicted to be insufficient if cAMP is otherwise freely diffusible. We tested the hypothesis that buffering of cAMP by protein kinase A (PKA) associated with A kinase anchoring proteins (AKAPs) slows cAMP diffusion and that this contributes to receptor-mediated, compartmentalized responses. EXPERIMENTAL APPROACH Raster image correlation spectroscopy (RICS) was used to measure intracellular cAMP diffusion coefficients and evaluate the contribution of PKA-AKAP interactions. Western blotting and immunocytochemistry were used to identify the AKAPs involved. RNA interference was used to down-regulate AKAP expression and determine its effects on cAMP diffusion. Compartmentalized cAMP responses were measured using fluorescence resonance energy transfer (FRET) based biosensors. KEY RESULTS Cyclic AMP movement was significantly slower than that of free-diffusion in hASM cells, and disrupting PKA-AKAP interactions significantly increased the diffusion coefficient. PKA associated with the outer mitochondrial membrane appears to play a prominent role in this effect. Consistent with this idea, knocking down expression of D-AKAP2, the primary mitochondrial AKAP, increased cAMP diffusion and disrupted compartmentation of receptor-mediated responses. CONCLUSION AND IMPLICATIONS Our results confirm that AKAP-anchored PKA contributes to the buffering of cAMP and is consequential in the compartmentation of cAMP responses in hASM cells.
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Affiliation(s)
- Rinzhin T Sherpa
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
| | - Karni S Moshal
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
| | - Shailesh R Agarwal
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
| | - Rennolds S Ostrom
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California, USA
| | - Robert D Harvey
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
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2
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Bock A, Irannejad R, Scott JD. cAMP signaling: a remarkably regional affair. Trends Biochem Sci 2024; 49:305-317. [PMID: 38310024 PMCID: PMC11175624 DOI: 10.1016/j.tibs.2024.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 12/22/2023] [Accepted: 01/10/2024] [Indexed: 02/05/2024]
Abstract
Louis Pasteur once famously said 'in the fields of observation chance favors only the prepared mind'. Much of chance is being in the right place at the right time. This is particularly true in the crowded molecular environment of the cell where being in the right place is often more important than timing. Although Brownian motion argues that enzymes will eventually bump into substrates, this probability is greatly enhanced if both molecules reside in the same subcellular compartment. However, activation of cell signaling enzymes often requires the transmission of chemical signals from extracellular stimuli to intracellular sites of action. This review highlights new developments in our understanding of cAMP generation and the 3D utilization of this second messenger inside cells.
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Affiliation(s)
- Andreas Bock
- Rudolf Boehm Institute of Pharmacology and Toxicology, Medical Faculty, Leipzig University, 04107 Leipzig, Germany.
| | - Roshanak Irannejad
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - John D Scott
- Department of Pharmacology, University of Washington Medical Center, Seattle, WA 98195, USA.
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3
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Nayak AP, Javed E, Villalba DR, Wang Y, Morelli HP, Shah SD, Kim N, Ostrom RS, Panettieri RA, An SS, Tang DD, Penn RB. Prorelaxant E-type Prostanoid Receptors Functionally Partition to Different Procontractile Receptors in Airway Smooth Muscle. Am J Respir Cell Mol Biol 2023; 69:584-591. [PMID: 37523713 PMCID: PMC10633839 DOI: 10.1165/rcmb.2022-0445oc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 07/31/2023] [Indexed: 08/02/2023] Open
Abstract
Prostaglandin E2 imparts diverse physiological effects on multiple airway cells through its actions on four distinct E-type prostanoid (EP) receptor subtypes (EP1-EP4). Gs-coupled EP2 and EP4 receptors are expressed on airway smooth muscle (ASM), yet their capacity to regulate the ASM contractile state remains subject to debate. We used EP2 and EP4 subtype-specific agonists (ONO-259 and ONO-329, respectively) in cell- and tissue-based models of human ASM contraction-magnetic twisting cytometry (MTC), and precision-cut lung slices (PCLSs), respectively-to study the EP2 and EP4 regulation of ASM contraction and signaling under conditions of histamine or methacholine (MCh) stimulation. ONO-329 was superior (<0.05) to ONO-259 in relaxing MCh-contracted PCLSs (log half maximal effective concentration [logEC50]: 4.9 × 10-7 vs. 2.2 × 10-6; maximal bronchodilation ± SE, 35 ± 2% vs. 15 ± 2%). However, ONO-259 and ONO-329 were similarly efficacious in relaxing histamine-contracted PCLSs. Similar differential effects were observed in MTC studies. Signaling analyses revealed only modest differences in ONO-329- and ONO-259-induced phosphorylation of the protein kinase A substrates VASP and HSP20, with concomitant stimulation with MCh or histamine. Conversely, ONO-259 failed to inhibit MCh-induced phosphorylation of the regulatory myosin light chain (pMLC20) and the F-actin/G-actin ratio (F/G-actin ratio) while effectively inhibiting their induction by histamine. ONO-329 was effective in reversing induced pMLC20 and the F/G-actin ratio with both MCh and histamine. Thus, the contractile-agonist-dependent differential effects are not explained by changes in the global levels of phosphorylated protein kinase A substrates but are reflected in the regulation of pMLC20 (cross-bridge cycling) and F/G-actin ratio (actin cytoskeleton integrity, force transmission), implicating a role for compartmentalized signaling involving muscarinic, histamine, and EP receptor subtypes.
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Affiliation(s)
- Ajay P. Nayak
- Center for Translational Medicine, Jane and Leonard Korman Lung Institute, Division of Pulmonary, Allergy & Critical Care Medicine, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Elham Javed
- Center for Translational Medicine, Jane and Leonard Korman Lung Institute, Division of Pulmonary, Allergy & Critical Care Medicine, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Dominic R. Villalba
- Center for Translational Medicine, Jane and Leonard Korman Lung Institute, Division of Pulmonary, Allergy & Critical Care Medicine, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Yinna Wang
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York
| | - Henry P. Morelli
- Center for Translational Medicine, Jane and Leonard Korman Lung Institute, Division of Pulmonary, Allergy & Critical Care Medicine, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Sushrut D. Shah
- Center for Translational Medicine, Jane and Leonard Korman Lung Institute, Division of Pulmonary, Allergy & Critical Care Medicine, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Nicholas Kim
- Rutgers Institute for Translational Medicine and Science, Rutgers University, New Brunswick, New Jersey
| | - Rennolds S. Ostrom
- Department of Biomedical and Pharmaceutical Sciences, School of Pharmacy, Chapman University, Irvine, California; and
| | - Reynold A. Panettieri
- Rutgers Institute for Translational Medicine and Science, Rutgers University, New Brunswick, New Jersey
| | - Steven S. An
- Rutgers Institute for Translational Medicine and Science, Rutgers University, New Brunswick, New Jersey
| | - Dale D. Tang
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York
| | - Raymond B. Penn
- Center for Translational Medicine, Jane and Leonard Korman Lung Institute, Division of Pulmonary, Allergy & Critical Care Medicine, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania
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4
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Dunn P, Annamdevula NS, Leavesley SJ, Rich TC, Phan AV. A two-dimensional finite element model of intercellular cAMP signaling through gap junction channels. J Biomech 2023; 152:111588. [PMID: 37094384 PMCID: PMC10173664 DOI: 10.1016/j.jbiomech.2023.111588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 04/02/2023] [Accepted: 04/11/2023] [Indexed: 04/26/2023]
Abstract
While cyclic adenosine monophosphate (cAMP) is typically considered an intracellular signal, it has been shown to spread between adjacent cells through connexin-based gap junction channels, promoting gap junctional intercellular communication (GJIC). Gap junction-mediated signaling is critical for the coordinated function of many tissues, and have been linked with cardiovascular disease, neurogenerative disease, and cancers. In particular, it plays a complex role in tumor suppression or promotion. This work introduces a two-dimensional finite element model that can describe intercellular cAMP signaling in the presence of gap junctions on membrane interfaces. The model was utilized to simulate cAMP transfer through one and two gap junction channels on the interface of a cluster of two pulmonary microvascular endothelial cells. The simulation results were found to generally agree with what has been observed in the literature in terms of GJIC. The research outcomes suggest that the proposed model can be employed to evaluate the permeability properties of a gap junction channel if its cAMP volumetric flow rate can be experimentally measured.
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Affiliation(s)
- P Dunn
- Department of Mechanical, Aerospace and Biomedical Engineering, University of South Alabama, Mobile, AL 36688, USA
| | - N S Annamdevula
- Center for Lung Biology & Department of Pharmacology University of South Alabama, Mobile, AL 36688, USA
| | - S J Leavesley
- Center for Lung Biology & Department of Pharmacology University of South Alabama, Mobile, AL 36688, USA; Department of Chemical and Biomolecular Engineering, University of South Alabama, Mobile, AL 36688, USA
| | - T C Rich
- Center for Lung Biology & Department of Pharmacology University of South Alabama, Mobile, AL 36688, USA
| | - A-V Phan
- Department of Mechanical, Aerospace and Biomedical Engineering, University of South Alabama, Mobile, AL 36688, USA.
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5
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Leavesley SJ, Johnson S, Paudel SS, Knighten J, Tambe DT, Francis M, Gong N, Taylor MS, Rich TC. Combined hyperspectral imaging, monolayer stress microscopy, and S8 image analysis approaches for simultaneously interrogating cellular signals and biomechanics. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2023; 12383:123830D. [PMID: 37051186 PMCID: PMC10084657 DOI: 10.1117/12.2650653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Abstract
Second messenger signals, e.g., Ca2+ and cyclic nucleotides, orchestrate a wide range of cellular events. The methods by which second messenger signals determine specific physiological responses are complex. Recent studies point to the importance of temporal and spatial encoding in determining signal specificity. Studies also indicate the importance of mechanical stimuli, substrate stiffness, and mechanical responses - the "mechanosome" - in regulating physiology. Hence, approaches that probe both chemical and mechanical signals are needed. Here, we report preliminary efforts to combine hyperspectral imaging for second messenger signal measurements, monolayer stress microscopy for mechanical force measurements, and S8 analysis software for quantifying localized signals - specifically, Ca2+ dynamics and mechanical forces in human airway smooth muscle cells (HASMCs). HASMCs were prepared as confluent monolayers on 11 kPa gels with embedded fluorescent microparticles that serve as fiducial markers as well as smaller microparticles to measure deformation (strain). Imaging was performed using a custom excitation-scanning hyperspectral microscope. Hyperspectral images were unmixed to identify signals from cellular fluorescent labels (e.g., CAL 590-AM) and fluorescent microparticles. Images were analyzed to quantify localized force dynamics through monolayer stress microscopy. S8 software was used to identify, track, and quantify spatially-localized Ca2+ activity. Results indicate that localized and transient cellular signals and forces can be quantified and mapped within cell populations. Importantly, these results establish a method for simultaneous interrogation of cellular signals and mechanical forces that may play synergistic roles in regulating downstream cellular physiology in confluent monolayers. This work was supported by NIH P01HL066299, R01HL137030, R01HL058506, and NSF MRI1725937. Drs. Leavesley and Rich disclose financial interest in a university start-up company, SpectraCyte LLC, to commercialize spectral imaging technologies.
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Affiliation(s)
- Silas J Leavesley
- Department of Chemical and Biomolecular Engineering
- Department of Pharmacology
- Center for Lung Biology
| | | | - Sunita S Paudel
- Center for Lung Biology
- Department of Physiology and Cell Biology
| | | | - Dhananjay T Tambe
- Department of Pharmacology
- Center for Lung Biology
- William B. Burnsed Jr. Department of Mechanical, Aerospace, and Biomedical Engineering
| | - Michael Francis
- Center for Lung Biology
- Department of Physiology and Cell Biology
| | - Na Gong
- Department of Electrical and Computer Engineering, University of South Alabama, Mobile, AL, USA 36688
| | - Mark S Taylor
- Center for Lung Biology
- Department of Physiology and Cell Biology
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6
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Bhadra A, Scruggs AK, Leavesley SJ, Annamdevula N, George AH, Britain AL, Francis CM, Knighten JM, Rich TC, Bauer NN. Extracellular vesicle-induced cyclic AMP signaling. Cell Signal 2022; 95:110348. [PMID: 35504529 PMCID: PMC10676271 DOI: 10.1016/j.cellsig.2022.110348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 04/26/2022] [Accepted: 04/27/2022] [Indexed: 11/25/2022]
Abstract
Second messenger signaling is required for cellular processes. We previously reported that extracellular vesicles (EVs) from stimulated cultured endothelial cells contain the biochemical second messenger, cAMP. In the current study, we sought to determine whether cAMP-enriched EVs induce second messenger signaling pathways in naïve recipient cells. Our results indicate that cAMP-enriched EVs increase cAMP content sufficient to stimulate PKA activity. The implications of our work are that EVs represent a novel intercellular mechanism for second messenger, specifically cAMP, signaling.
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Affiliation(s)
- Aritra Bhadra
- Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL, United States of America; Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, Alabama
| | - April K Scruggs
- Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL, United States of America; Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, Alabama
| | - Silas J Leavesley
- Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL, United States of America; Department of Chemical and Biomolecular Engineering, College of Engineering, University of South Alabama, Mobile, AL, United States of America; Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, Alabama
| | - Naga Annamdevula
- Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL, United States of America; Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, Alabama
| | - April H George
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, Alabama
| | - Andrea L Britain
- Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL, United States of America; Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, Alabama
| | - Christopher M Francis
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, AL, United States of America; Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, Alabama
| | - Jennifer M Knighten
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, AL, United States of America; Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, Alabama
| | - Thomas C Rich
- Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL, United States of America; Department of Physiology and Cell Biology, University of South Alabama, Mobile, AL, United States of America
| | - Natalie N Bauer
- Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL, United States of America; Department of Physiology and Cell Biology, University of South Alabama, Mobile, AL, United States of America.
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7
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Computational investigation of the dynamic control of cAMP signaling by PDE4 isoform types. Biophys J 2022; 121:2693-2711. [PMID: 35717559 DOI: 10.1016/j.bpj.2022.06.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 05/03/2022] [Accepted: 06/14/2022] [Indexed: 11/24/2022] Open
Abstract
Cyclic adenosine monophosphate (cAMP) is a generic signaling molecule that, through precise control of its signaling dynamics, exerts distinct cellular effects. Consequently, aberrant cAMP signaling can have detrimental effects. Phosphodiesterase 4 (PDE4) enzymes profoundly control cAMP signaling and comprise different isoform types of which the enzymatic activity is modulated by differential feedback mechanisms. Because these feedback dynamics are non-linear and occur coincidentally, their effects are difficult to examine experimentally, but can be well simulated computationally. Through understanding the role of PDE4 isoform types in regulating cAMP signaling, PDE4-targeted therapeutic strategies can be better specified. Here, we established a computational model to study how feedback mechanisms on different PDE4 isoform types lead to dynamic, isoform-specific control of cAMP signaling. Ordinary differential equations describing cAMP dynamics were implemented in the VirtualCell (VCell) environment. Simulations indicated that long PDE4 isoforms exert the most profound control on oscillatory cAMP signaling, as opposed to the PDE4-mediated control of single cAMP input pulses. Moreover, elevating cAMP levels or decreasing PDE4 levels revealed different effects on downstream signaling. Together these results underline that cAMP signaling is distinctly regulated by different PDE4 isoform types and that this isoform-specificity should be considered in both computational and experimental follow-up studies to better define PDE4 enzymes as therapeutic targets in diseases in which cAMP signaling is aberrant.
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8
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A multiscale model of the regulation of aquaporin 2 recycling. NPJ Syst Biol Appl 2022; 8:16. [PMID: 35534498 PMCID: PMC9085758 DOI: 10.1038/s41540-022-00223-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 03/24/2022] [Indexed: 11/08/2022] Open
Abstract
The response of cells to their environment is driven by a variety of proteins and messenger molecules. In eukaryotes, their distribution and location in the cell are regulated by the vesicular transport system. The transport of aquaporin 2 between membrane and storage region is a crucial part of the water reabsorption in renal principal cells, and its malfunction can lead to Diabetes insipidus. To understand the regulation of this system, we aggregated pathways and mechanisms from literature and derived three models in a hypothesis-driven approach. Furthermore, we combined the models to a single system to gain insight into key regulatory mechanisms of Aquaporin 2 recycling. To achieve this, we developed a multiscale computational framework for the modeling and simulation of cellular systems. The analysis of the system rationalizes that the compartmentalization of cAMP in renal principal cells is a result of the protein kinase A signalosome and can only occur if specific cellular components are observed in conjunction. Endocytotic and exocytotic processes are inherently connected and can be regulated by the same protein kinase A signal.
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9
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Adams D, Choi CS, Sayner SL. Pulmonary endothelial cells from different vascular segments exhibit unique recovery from acidification and Na+/H+ exchanger isoform expression. PLoS One 2022; 17:e0266890. [PMID: 35503765 PMCID: PMC9064095 DOI: 10.1371/journal.pone.0266890] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 03/29/2022] [Indexed: 12/29/2022] Open
Abstract
Sodium-hydrogen exchangers (NHEs) tightly regulate intracellular pH (pHi), proliferation, migration and cell volume. Heterogeneity exists between pulmonary endothelial cells derived from different vascular segments, yet the activity and isoform expression of NHEs between these vascular segments has not been fully examined. Utilizing the ammonium-prepulse and recovery from acidification technique in a buffer lacking bicarbonate, pulmonary microvascular and pulmonary artery endothelial cells exhibited unique recovery rates from the acid load dependent upon the concentration of the sodium transport inhibitor, amiloride; further, pulmonary artery endothelial cells required a higher dose of amiloride to inhibit sodium-dependent acid recovery compared to pulmonary microvascular endothelial cells, suggesting a unique complement of NHEs between the different endothelial cell types. While NHE1 has been described in pulmonary endothelial cells, all NHE isoforms have not been accounted for. To address NHE expression in endothelial cells, qPCR was performed. Using a two-gene normalization approach, Sdha and Ywhag were identified for qPCR normalization and analysis of NHE isoforms between pulmonary microvascular and pulmonary artery endothelial cells. NHE1 and NHE8 mRNA were equally expressed between the two cell types, but NHE5 expression was significantly higher in pulmonary microvascular versus pulmonary artery endothelial cells, which was confirmed at the protein level. Thus, pulmonary microvascular and pulmonary artery endothelial cells exhibit unique NHE isoform expression and have a unique response to acid load revealed through recovery from cellular acidification.
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Affiliation(s)
- Dylan Adams
- Department of Physiology and Cell Biology, University South Alabama, College of Medicine, Mobile, Alabama, United States of America
| | - Chung-Sik Choi
- Department of Physiology and Cell Biology, University South Alabama, College of Medicine, Mobile, Alabama, United States of America
| | - Sarah L. Sayner
- Department of Physiology and Cell Biology, University South Alabama, College of Medicine, Mobile, Alabama, United States of America
- Center for Lung Biology, University of South Alabama, College of Medicine, Mobile, Alabama, United States of America
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10
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Leavesley SJ, Annamdevula N, Johnson S, Pleshinger DJ, Rich TC. Automated Image Analysis of FRET Signals for Subcellular cAMP Quantification. Methods Mol Biol 2022; 2483:167-180. [PMID: 35286675 DOI: 10.1007/978-1-0716-2245-2_10] [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] [Indexed: 06/14/2023]
Abstract
A variety of FRET probes have been developed to examine cAMP localization and dynamics in single cells. These probes offer a readily accessible approach to measure localized cAMP signals. However, given the low signal-to-noise ratio of most FRET probes and the dynamic nature of the intracellular environment, there have been marked limitations in the ability to use FRET probes to study localized signaling events within the same cell. Here, we outline a methodology to dissect kinetics of cAMP-mediated FRET signals in single cells using automated image analysis approaches. We additionally extend these approaches to the analysis of subcellular regions. These approaches offer a unique opportunity to assess localized cAMP kinetics in an unbiased, quantitative fashion.
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Affiliation(s)
- Silas J Leavesley
- Department of Chemical and Biomolecular Engineering, University of South Alabama, Mobile, AL, USA.
- Department of Pharmacology, University of South Alabama, Mobile, AL, USA.
- Center for Lung Biology, University of South Alabama, Mobile, AL, USA.
| | - Naga Annamdevula
- Department of Pharmacology, University of South Alabama, Mobile, AL, USA
- Center for Lung Biology, University of South Alabama, Mobile, AL, USA
- Department of Physiology, University of South Alabama, Mobile, AL, USA
| | - Santina Johnson
- Department of Pharmacology, University of South Alabama, Mobile, AL, USA
- Center for Lung Biology, University of South Alabama, Mobile, AL, USA
| | - D J Pleshinger
- Department of Pharmacology, University of South Alabama, Mobile, AL, USA
- Center for Lung Biology, University of South Alabama, Mobile, AL, USA
| | - Thomas C Rich
- Department of Pharmacology, University of South Alabama, Mobile, AL, USA
- Center for Lung Biology, University of South Alabama, Mobile, AL, USA
- Department of Physiology, University of South Alabama, Mobile, AL, USA
- College of Engineering, University of South Alabama, Mobile, AL, USA
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11
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Warren R, Rich T, Leavesley S, Phan AV. A three-dimensional finite element model of cAMP signals. FORCES IN MECHANICS 2021; 4. [PMID: 35072121 PMCID: PMC8773462 DOI: 10.1016/j.finmec.2021.100041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- R. Warren
- Department of Mechanical, Aerospace and Biomedical Engineering, University of South Alabama, Mobile, AL 36688, USA
| | - T.C. Rich
- Center for Lung Biology & Department of Pharmacology, University of South Alabama, Mobile, AL 36688, USA
| | - S.J. Leavesley
- Center for Lung Biology & Department of Pharmacology, University of South Alabama, Mobile, AL 36688, USA
- Department of Chemical and Biomolecular Engineering, University of South Alabama, Mobile, AL 36688, USA
| | - A.-V. Phan
- Department of Mechanical, Aerospace and Biomedical Engineering, University of South Alabama, Mobile, AL 36688, USA
- Corresponding author. (A.-V. Phan)
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12
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Harvey RD, Clancy CE. Mechanisms of cAMP compartmentation in cardiac myocytes: experimental and computational approaches to understanding. J Physiol 2021; 599:4527-4544. [PMID: 34510451 DOI: 10.1113/jp280801] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 09/07/2021] [Indexed: 01/04/2023] Open
Abstract
The small diffusible second messenger 3',5'-cyclic adenosine monophosphate (cAMP) is found in virtually every cell in our bodies, where it mediates responses to a variety of different G protein coupled receptors (GPCRs). In the heart, cAMP plays a critical role in regulating many different aspects of cardiac myocyte function, including gene transcription, cell metabolism, and excitation-contraction coupling. Yet, not all GPCRs that stimulate cAMP production elicit the same responses. Subcellular compartmentation of cAMP is essential to explain how different receptors can utilize the same diffusible second messenger to elicit unique functional responses. However, the mechanisms contributing to this behaviour and its significance in producing physiological and pathological responses are incompletely understood. Mathematical modelling has played an essential role in gaining insight into these questions. This review discusses what we currently know about cAMP compartmentation in cardiac myocytes and questions that are yet to be answered.
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Affiliation(s)
- Robert D Harvey
- Department of Pharmacology, University of Nevada, Reno, NV, 89557, USA
| | - Colleen E Clancy
- Department of Physiology and Membrane Biology, University of California-Davis, Davis, CA, 95616, USA
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13
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Sherpa RT, Fiore C, Moshal KS, Wadsworth A, Rudokas MW, Agarwal SR, Harvey RD. Mitochondrial A-kinase anchoring proteins in cardiac ventricular myocytes. Physiol Rep 2021; 9:e15015. [PMID: 34514737 PMCID: PMC8436057 DOI: 10.14814/phy2.15015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/02/2021] [Accepted: 08/04/2021] [Indexed: 12/30/2022] Open
Abstract
Compartmentation of cAMP signaling is a critical factor for maintaining the integrity of receptor-specific responses in cardiac myocytes. This phenomenon relies on various factors limiting cAMP diffusion. Our previous work in adult rat ventricular myocytes (ARVMs) indicates that PKA regulatory subunits anchored to the outer membrane of mitochondria play a key role in buffering the movement of cytosolic cAMP. PKA can be targeted to discrete subcellular locations through the interaction of both type I and type II regulatory subunits with A-kinase anchoring proteins (AKAPs). The purpose of this study is to identify which AKAPs and PKA regulatory subunit isoforms are associated with mitochondria in ARVMs. Quantitative PCR data demonstrate that mRNA for dual specific AKAP1 and 2 (D-AKAP1 & D-AKAP2), acyl-CoA-binding domain-containing 3 (ACBD3), optic atrophy 1 (OPA1) are most abundant, while Rab32, WAVE-1, and sphingosine kinase type 1 interacting protein (SPHKAP) were barely detectable. Biochemical and immunocytochemical analysis suggests that D-AKAP1, D-AKAP2, and ACBD3 are the predominant mitochondrial AKAPs exposed to the cytosolic compartment in these cells. Furthermore, we show that both type I and type II regulatory subunits of PKA are associated with mitochondria. Taken together, these data suggest that D-AKAP1, D-AKAP2, and ACBD3 may be responsible for tethering both type I and type II PKA regulatory subunits to the outer mitochondrial membrane in ARVMs. In addition to regulating PKA-dependent mitochondrial function, these AKAPs may play an important role by buffering the movement of cAMP necessary for compartmentation.
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Affiliation(s)
| | - Chase Fiore
- Department of PharmacologyUniversity of NevadaRenoNevadaUSA
| | | | - Adam Wadsworth
- Department of PharmacologyUniversity of NevadaRenoNevadaUSA
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14
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cAMP Compartmentalization in Cerebrovascular Endothelial Cells: New Therapeutic Opportunities in Alzheimer's Disease. Cells 2021; 10:cells10081951. [PMID: 34440720 PMCID: PMC8392343 DOI: 10.3390/cells10081951] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/19/2021] [Accepted: 07/28/2021] [Indexed: 12/20/2022] Open
Abstract
The vascular hypothesis used to explain the pathophysiology of Alzheimer’s disease (AD) suggests that a dysfunction of the cerebral microvasculature could be the beginning of alterations that ultimately leads to neuronal damage, and an abnormal increase of the blood–brain barrier (BBB) permeability plays a prominent role in this process. It is generally accepted that, in physiological conditions, cyclic AMP (cAMP) plays a key role in maintaining BBB permeability by regulating the formation of tight junctions between endothelial cells of the brain microvasculature. It is also known that intracellular cAMP signaling is highly compartmentalized into small nanodomains and localized cAMP changes are sufficient at modifying the permeability of the endothelial barrier. This spatial and temporal distribution is maintained by the enzymes involved in cAMP synthesis and degradation, by the location of its effectors, and by the existence of anchor proteins, as well as by buffers or different cytoplasm viscosities and intracellular structures limiting its diffusion. This review compiles current knowledge on the influence of cAMP compartmentalization on the endothelial barrier and, more specifically, on the BBB, laying the foundation for a new therapeutic approach in the treatment of AD.
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15
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McCabe KJ, Rangamani P. Computational modeling approaches to cAMP/PKA signaling in cardiomyocytes. J Mol Cell Cardiol 2021; 154:32-40. [PMID: 33548239 DOI: 10.1016/j.yjmcc.2021.01.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 01/11/2021] [Accepted: 01/15/2021] [Indexed: 12/12/2022]
Abstract
The cAMP/PKA pathway is a fundamental regulator of excitation-contraction coupling in cardiomyocytes. Activation of cAMP has a variety of downstream effects on cardiac function including enhanced contraction, accelerated relaxation, adaptive stress response, mitochondrial regulation, and gene transcription. Experimental advances have shed light on the compartmentation of cAMP and PKA, which allow for control over the varied targets of these second messengers and is disrupted in heart failure conditions. Computational modeling is an important tool for understanding the spatial and temporal complexities of this system. In this review article, we outline the advances in computational modeling that have allowed for deeper understanding of cAMP/PKA dynamics in the cardiomyocyte in health and disease, and explore new modeling frameworks that may bring us closer to a more complete understanding of this system. We outline various compartmental and spatial signaling models that have been used to understand how β-adrenergic signaling pathways function in a variety of simulation conditions. We also discuss newer subcellular models of cardiovascular function that may be used as templates for the next phase of computational study of cAMP and PKA in the heart, and outline open challenges which are important to consider in future models.
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Affiliation(s)
- Kimberly J McCabe
- Simula Research Laboratory, Department of Computational Physiology, PO Box 134, 1325 Lysaker, Norway.
| | - Padmini Rangamani
- University of California San Diego, Department of Mechanical and Aerospace Engineering, 9500 Gilman Drive MC 0411, La Jolla, CA 92093, United States of America
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16
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Abstract
The field of cAMP signaling is witnessing exciting developments with the recognition that cAMP is compartmentalized and that spatial regulation of cAMP is critical for faithful signal coding. This realization has changed our understanding of cAMP signaling from a model in which cAMP connects a receptor at the plasma membrane to an intracellular effector in a linear pathway to a model in which cAMP signals propagate within a complex network of alternative branches and the specific functional outcome strictly depends on local regulation of cAMP levels and on selective activation of a limited number of branches within the network. In this review, we cover some of the early studies and summarize more recent evidence supporting the model of compartmentalized cAMP signaling, and we discuss how this knowledge is starting to provide original mechanistic insight into cell physiology and a novel framework for the identification of disease mechanisms that potentially opens new avenues for therapeutic interventions.
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Affiliation(s)
- Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Anna Zerio
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Miguel J Lobo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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17
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Bock A, Annibale P, Konrad C, Hannawacker A, Anton SE, Maiellaro I, Zabel U, Sivaramakrishnan S, Falcke M, Lohse MJ. Optical Mapping of cAMP Signaling at the Nanometer Scale. Cell 2020; 182:1519-1530.e17. [PMID: 32846156 DOI: 10.1016/j.cell.2020.07.035] [Citation(s) in RCA: 104] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 03/30/2020] [Accepted: 07/23/2020] [Indexed: 10/23/2022]
Abstract
Cells relay a plethora of extracellular signals to specific cellular responses by using only a few second messengers, such as cAMP. To explain signaling specificity, cAMP-degrading phosphodiesterases (PDEs) have been suggested to confine cAMP to distinct cellular compartments. However, measured rates of fast cAMP diffusion and slow PDE activity render cAMP compartmentalization essentially impossible. Using fluorescence spectroscopy, we show that, contrary to earlier data, cAMP at physiological concentrations is predominantly bound to cAMP binding sites and, thus, immobile. Binding and unbinding results in largely reduced cAMP dynamics, which we term "buffered diffusion." With a large fraction of cAMP being buffered, PDEs can create nanometer-size domains of low cAMP concentrations. Using FRET-cAMP nanorulers, we directly map cAMP gradients at the nanoscale around PDE molecules and the areas of resulting downstream activation of cAMP-dependent protein kinase (PKA). Our study reveals that spatiotemporal cAMP signaling is under precise control of nanometer-size domains shaped by PDEs that gate activation of downstream effectors.
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Affiliation(s)
- Andreas Bock
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Robert-Rössle-Str. 10, 13125 Berlin, Germany; Institute of Pharmacology and Toxicology, University of Würzburg, Versbacher Str. 9, 97078 Würzburg, Germany.
| | - Paolo Annibale
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Robert-Rössle-Str. 10, 13125 Berlin, Germany; Institute of Pharmacology and Toxicology, University of Würzburg, Versbacher Str. 9, 97078 Würzburg, Germany
| | - Charlotte Konrad
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Robert-Rössle-Str. 10, 13125 Berlin, Germany; Institute of Pharmacology and Toxicology, University of Würzburg, Versbacher Str. 9, 97078 Würzburg, Germany
| | - Annette Hannawacker
- Institute of Pharmacology and Toxicology, University of Würzburg, Versbacher Str. 9, 97078 Würzburg, Germany
| | - Selma E Anton
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Robert-Rössle-Str. 10, 13125 Berlin, Germany; Institute of Pharmacology and Toxicology, University of Würzburg, Versbacher Str. 9, 97078 Würzburg, Germany
| | - Isabella Maiellaro
- Institute of Pharmacology and Toxicology, University of Würzburg, Versbacher Str. 9, 97078 Würzburg, Germany
| | - Ulrike Zabel
- Institute of Pharmacology and Toxicology, University of Würzburg, Versbacher Str. 9, 97078 Würzburg, Germany
| | - Sivaraj Sivaramakrishnan
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Martin Falcke
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Robert-Rössle-Str. 10, 13125 Berlin, Germany; Department of Physics, Humboldt University, Newtonstr. 15, 12489 Berlin, Germany
| | - Martin J Lohse
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Robert-Rössle-Str. 10, 13125 Berlin, Germany; Institute of Pharmacology and Toxicology, University of Würzburg, Versbacher Str. 9, 97078 Würzburg, Germany; Institute for Chemistry and Biochemistry, Free University, Takustr. 3, 14195 Berlin, Germany; ISAR Bioscience Institute, 82152 Munich/Planegg, Germany.
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18
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Renema P, Hardy KS, Housley N, Dunbar G, Annamdevula N, Britain A, Spadafora D, Leavesley S, Rich T, Audia JP, Alvarez DF. cAMP signaling primes lung endothelial cells to activate caspase-1 during Pseudomonas aeruginosa infection. Am J Physiol Lung Cell Mol Physiol 2020; 318:L1074-L1083. [PMID: 32186399 DOI: 10.1152/ajplung.00185.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Activation of the inflammasome-caspase-1 axis in lung endothelial cells is emerging as a novel arm of the innate immune response to pneumonia and sepsis caused by Pseudomonas aeruginosa. Increased levels of circulating autacoids are hallmarks of pneumonia and sepsis and induce physiological responses via cAMP signaling in targeted cells. However, it is unknown whether cAMP affects other functions, such as P. aeruginosa-induced caspase-1 activation. Herein, we describe the effects of cAMP signaling on caspase-1 activation using a single cell flow cytometry-based assay. P. aeruginosa infection of cultured lung endothelial cells caused caspase-1 activation in a distinct population of cells. Unexpectedly, pharmacological cAMP elevation increased the total number of lung endothelial cells with activated caspase-1. Interestingly, addition of cAMP agonists augmented P. aeruginosa infection of lung endothelial cells as a partial explanation underlying cAMP priming of caspase-1 activation. The cAMP effect(s) appeared to function as a priming signal because addition of cAMP agonists was required either before or early during the onset of infection. However, absolute cAMP levels measured by ELISA were not predictive of cAMP-priming effects. Importantly, inhibition of de novo cAMP synthesis decreased the number of lung endothelial cells with activated caspase-1 during infection. Collectively, our data suggest that lung endothelial cells rely on cAMP signaling to prime caspase-1 activation during P. aeruginosa infection.
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Affiliation(s)
- Phoibe Renema
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama.,Center for Lung Biology, University of South Alabama, Mobile, Alabama
| | - Kierra S Hardy
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama.,Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama.,Center for Lung Biology, University of South Alabama, Mobile, Alabama
| | - Nicole Housley
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama.,Center for Lung Biology, University of South Alabama, Mobile, Alabama
| | - Grace Dunbar
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama.,Center for Lung Biology, University of South Alabama, Mobile, Alabama
| | - Naga Annamdevula
- Department of Pharmacology, University of South Alabama, Mobile, Alabama.,Center for Lung Biology, University of South Alabama, Mobile, Alabama
| | - Andrea Britain
- Department of Pharmacology, University of South Alabama, Mobile, Alabama.,Center for Lung Biology, University of South Alabama, Mobile, Alabama
| | | | - Silas Leavesley
- Department of Chemical and Biomolecular Engineering, University of South Alabama, Mobile, Alabama.,Center for Lung Biology, University of South Alabama, Mobile, Alabama
| | - Thomas Rich
- Department of Pharmacology, University of South Alabama, Mobile, Alabama.,Center for Lung Biology, University of South Alabama, Mobile, Alabama
| | - Jonathon P Audia
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama.,Center for Lung Biology, University of South Alabama, Mobile, Alabama
| | - Diego F Alvarez
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama.,Center for Lung Biology, University of South Alabama, Mobile, Alabama
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19
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Nanometric targeting of type 9 adenylyl cyclase in heart. Biochem Soc Trans 2020; 47:1749-1756. [PMID: 31769471 DOI: 10.1042/bst20190227] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 11/11/2019] [Accepted: 11/12/2019] [Indexed: 12/15/2022]
Abstract
Adenylyl cyclases (ACs) convert ATP into the classical second messenger cyclic adenosine monophosphate (cAMP). Cardiac ACs, specifically AC5, AC6, and AC9, regulate cAMP signaling controlling functional outcomes such as heart rate, contractility and relaxation, gene regulation, stress responses, and glucose and lipid metabolism. With so many distinct functional outcomes for a single second messenger, the cell creates local domains of cAMP signaling to correctly relay signals. Targeting of ACs to A-kinase anchoring proteins (AKAPs) not only localizes ACs, but also places them within signaling nanodomains, where cAMP levels and effects can be highly regulated. Here we will discuss the recent work on the structure, regulation and physiological functions of AC9 in the heart, where it accounts for <3% of total AC activity. Despite the small contribution of AC9 to total cardiac cAMP production, AC9 binds and regulates local PKA phosphorylation of Yotiao-IKs and Hsp20, demonstrating a role for nanometric targeting of AC9.
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20
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Stone N, Shettlesworth S, Rich TC, Leavesley SJ, Phan AV. A two-dimensional finite element model of cyclic adenosine monophosphate (cAMP) intracellular signaling. SN APPLIED SCIENCES 2019; 1. [PMID: 33615142 DOI: 10.1007/s42452-019-1757-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
In this work, we present a two-dimensional finite element analysis (FEA) model that describes fundamental intracellular signals of cyclic adenosine monophosphate (cAMP) in a general fashion. The model was subsequently solved numerically and the results were displayed in forms of time-course plots of cAMP concentration at a cellular location or color-filled contour maps of cAMP signal distribution within the cell at specific time points. Basic intracellular cAMP signaling was described in this model so it can be numerically validated by verifying its numerical results against available analytical solutions and against results obtained from other numerical techniques reported in the literature. This is the first important step before the model can be expanded in future work. Model simulations demonstrate that under certain conditions, sustained cAMP concentrations can be formed within endothelial cells (ECs), similar to those observed in rat pulmonary microvascular ECs. Spatial and temporal cAMP dynamic simulations indicated that the proposed FEA model is an effective tool for the study of the kinetics and spatial spread of second messenger signaling and can be expanded to simulate second messenger signals in the pulmonary vasculature.
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Affiliation(s)
- N Stone
- William B. Burnsed, Jr. Department of Mechanical Engineering, University of South Alabama, Mobile, AL 36688, USA
| | - S Shettlesworth
- William B. Burnsed, Jr. Department of Mechanical Engineering, University of South Alabama, Mobile, AL 36688, USA
| | - T C Rich
- Center for Lung Biology & Department of Pharmacology, University of South Alabama, Mobile, AL 36688, USA
| | - S J Leavesley
- Department of Chemical and Biomolecular Engineering & Department of Pharmacology, University of South Alabama, Mobile, AL 36688, USA
| | - A-V Phan
- William B. Burnsed, Jr. Department of Mechanical Engineering, University of South Alabama, Mobile, AL 36688, USA
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21
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Geometric Control of Frequency Modulation of cAMP Oscillations due to Calcium in Dendritic Spines. Biophys J 2019; 117:1981-1994. [PMID: 31668747 PMCID: PMC7018999 DOI: 10.1016/j.bpj.2019.10.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 07/30/2019] [Accepted: 10/02/2019] [Indexed: 12/12/2022] Open
Abstract
The spatiotemporal regulation of cyclic adenosine monophosphate (cAMP) and its dynamic interactions with other second messengers such as calcium are critical features of signaling specificity required for neuronal development and connectivity. cAMP is known to contribute to long-term potentiation and memory formation by controlling the formation and regulation of dendritic spines. Despite the recent advances in biosensing techniques for monitoring spatiotemporal cAMP dynamics, the underlying molecular mechanisms that attribute to the subcellular modulation of cAMP remain unknown. In this work, we model the spatiotemporal dynamics of calcium-induced cAMP signaling pathway in dendritic spines. Using a three-dimensional reaction-diffusion model, we investigate the effect of different spatial characteristics of cAMP dynamics that may be responsible for subcellular regulation of cAMP concentrations. Our model predicts that the volume/surface ratio of the spine, regulated through the spine head size, spine neck size, and the presence of physical barriers (spine apparatus), is an important regulator of cAMP dynamics. Furthermore, localization of the enzymes responsible for the synthesis and degradation of cAMP in different compartments also modulates the oscillatory patterns of cAMP through exponential relationships. Our findings shed light on the significance of complex geometric and localization relationships for cAMP dynamics in dendritic spines.
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22
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Naim N, White AD, Reece JM, Wankhede M, Zhang X, Vilardaga JP, Altschuler DL. Luminescence-activated nucleotide cyclase regulates spatial and temporal cAMP synthesis. J Biol Chem 2018; 294:1095-1103. [PMID: 30559293 DOI: 10.1074/jbc.ac118.004905] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 12/12/2018] [Indexed: 12/15/2022] Open
Abstract
cAMP is a ubiquitous second messenger that regulates cellular proliferation, differentiation, attachment, migration, and several other processes. It has become increasingly evident that tight regulation of cAMP accumulation and localization confers divergent yet specific signaling to downstream pathways. Currently, few tools are available that have sufficient spatial and temporal resolution to study location-biased cAMP signaling. Here, we introduce a new fusion protein consisting of a light-activated adenylyl cyclase (bPAC) and luciferase (nLuc). This construct allows dual activation of cAMP production through temporally precise photostimulation or chronic chemical stimulation that can be fine-tuned to mimic physiological levels and duration of cAMP synthesis to trigger downstream events. By targeting this construct to different compartments, we show that cAMP produced in the cytosol and nucleus stimulates proliferation in thyroid cells. The bPAC-nLuc fusion construct adds a new reagent to the available toolkit to study cAMP-regulated processes in living cells.
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Affiliation(s)
- Nyla Naim
- Department of Pharmacology and Chemical Biology, Pittsburgh, Pennsylvania 15261; Molecular Pharmacology Training Program, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Alex D White
- Department of Pharmacology and Chemical Biology, Pittsburgh, Pennsylvania 15261; Molecular Pharmacology Training Program, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Jeff M Reece
- Department of Pharmacology and Chemical Biology, Pittsburgh, Pennsylvania 15261
| | - Mamta Wankhede
- Department of Pharmacology and Chemical Biology, Pittsburgh, Pennsylvania 15261
| | - Xuefeng Zhang
- Department of Pharmacology and Chemical Biology, Pittsburgh, Pennsylvania 15261
| | | | - Daniel L Altschuler
- Department of Pharmacology and Chemical Biology, Pittsburgh, Pennsylvania 15261.
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23
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Greenwald EC, Mehta S, Zhang J. Genetically Encoded Fluorescent Biosensors Illuminate the Spatiotemporal Regulation of Signaling Networks. Chem Rev 2018; 118:11707-11794. [PMID: 30550275 DOI: 10.1021/acs.chemrev.8b00333] [Citation(s) in RCA: 295] [Impact Index Per Article: 49.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cellular signaling networks are the foundation which determines the fate and function of cells as they respond to various cues and stimuli. The discovery of fluorescent proteins over 25 years ago enabled the development of a diverse array of genetically encodable fluorescent biosensors that are capable of measuring the spatiotemporal dynamics of signal transduction pathways in live cells. In an effort to encapsulate the breadth over which fluorescent biosensors have expanded, we endeavored to assemble a comprehensive list of published engineered biosensors, and we discuss many of the molecular designs utilized in their development. Then, we review how the high temporal and spatial resolution afforded by fluorescent biosensors has aided our understanding of the spatiotemporal regulation of signaling networks at the cellular and subcellular level. Finally, we highlight some emerging areas of research in both biosensor design and applications that are on the forefront of biosensor development.
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Affiliation(s)
- Eric C Greenwald
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
| | - Sohum Mehta
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
| | - Jin Zhang
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
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24
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Annamdevula NS, Sweat R, Griswold JR, Trinh K, Hoffman C, West S, Deal J, Britain AL, Jalink K, Rich TC, Leavesley SJ. Spectral imaging of FRET-based sensors reveals sustained cAMP gradients in three spatial dimensions. Cytometry A 2018; 93:1029-1038. [PMID: 30176184 DOI: 10.1002/cyto.a.23572] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 06/21/2018] [Accepted: 07/09/2018] [Indexed: 11/10/2022]
Abstract
Cyclic AMP is a ubiquitous second messenger that orchestrates a variety of cellular functions over different timescales. The mechanisms underlying specificity within this signaling pathway are still not well understood. Several lines of evidence suggest the existence of spatial cAMP gradients within cells, and that compartmentalization underlies specificity within the cAMP signaling pathway. However, to date, no studies have visualized cAMP gradients in three spatial dimensions (3D: x, y, z).This is in part due to the limitations of FRET-based cAMP sensors, specifically the low signal-to-noise ratio intrinsic to all intracellular FRET probes. Here, we overcome this limitation, at least in part, by implementing spectral imaging approaches to estimate FRET efficiency when multiple fluorescent labels are used and when signals are measured from weakly expressed fluorescent proteins in the presence of background autofluorescence and stray light. Analysis of spectral image stacks in two spatial dimensions (2D) from single confocal slices indicates little or no cAMP gradients formed within pulmonary microvascular endothelial cells (PMVECs) under baseline conditions or following 10 min treatment with the adenylyl cyclase activator forskolin. However, analysis of spectral image stacks in 3D demonstrates marked cAMP gradients from the apical to basolateral face of PMVECs. Results demonstrate that spectral imaging approaches can be used to assess cAMP gradients-and in general gradients in fluorescence and FRET-within intact cells. Results also demonstrate that 2D imaging studies of localized fluorescence signals and, in particular, cAMP signals, whether using epifluorescence or confocal microscopy, may lead to erroneous conclusions about the existence and/or magnitude of gradients in either FRET or the underlying cAMP signals. Thus, with the exception of cellular structures that can be considered in one spatial dimension, such as neuronal processes, 3D measurements are required to assess mechanisms underlying compartmentalization and specificity within intracellular signaling pathways.
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Affiliation(s)
- Naga S Annamdevula
- Department of Chemical & Biomolecular Engineering, University of South Alabama, Mobile, Alabama.,Center for Lung Biology, University of South Alabama, Mobile, Alabama
| | - Rachel Sweat
- Department of Chemical & Biomolecular Engineering, University of South Alabama, Mobile, Alabama
| | - John R Griswold
- Department of Chemical & Biomolecular Engineering, University of South Alabama, Mobile, Alabama
| | - Kenny Trinh
- Department of Chemical & Biomolecular Engineering, University of South Alabama, Mobile, Alabama
| | - Chase Hoffman
- Medical Sciences, University of South Alabama, Mobile, Alabama
| | - Savannah West
- Department of Biomedical Sciences, University of South Alabama, Mobile, Alabama
| | - Joshua Deal
- Department of Chemical & Biomolecular Engineering, University of South Alabama, Mobile, Alabama.,Center for Lung Biology, University of South Alabama, Mobile, Alabama
| | - Andrea L Britain
- Center for Lung Biology, University of South Alabama, Mobile, Alabama.,Department of Pharmacology, University of South Alabama, Mobile, Alabama
| | - Kees Jalink
- The Netherlands Cancer Institute and van Leeuwenhoek Center for Advanced Microscopy, Amsterdam, the Netherlands
| | - Thomas C Rich
- Center for Lung Biology, University of South Alabama, Mobile, Alabama.,Department of Pharmacology, University of South Alabama, Mobile, Alabama.,College of Engineering, University of South Alabama, Mobile, Alabama
| | - Silas J Leavesley
- Department of Chemical & Biomolecular Engineering, University of South Alabama, Mobile, Alabama.,Center for Lung Biology, University of South Alabama, Mobile, Alabama.,Department of Pharmacology, University of South Alabama, Mobile, Alabama
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25
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Filadi R, Basso E, Lefkimmiatis K, Pozzan T. Beyond Intracellular Signaling: The Ins and Outs of Second Messengers Microdomains. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 981:279-322. [PMID: 29594866 DOI: 10.1007/978-3-319-55858-5_12] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A typical characteristic of eukaryotic cells compared to prokaryotes is represented by the spatial heterogeneity of the different structural and functional components: for example, most of the genetic material is surrounded by a highly specific membrane structure (the nuclear membrane), continuous with, yet largely different from, the endoplasmic reticulum (ER); oxidative phosphorylation is carried out by organelles enclosed by a double membrane, the mitochondria; in addition, distinct domains, enriched in specific proteins, are present in the plasma membrane (PM) of most cells. Less obvious, but now generally accepted, is the notion that even the concentration of small molecules such as second messengers (Ca2+ and cAMP in particular) can be highly heterogeneous within cells. In the case of most organelles, the differences in the luminal levels of second messengers depend either on the existence on their membrane of proteins that allow the accumulation/release of the second messenger (e.g., in the case of Ca2+, pumps, exchangers or channels), or on the synthesis and degradation of the specific molecule within the lumen (the autonomous intramitochondrial cAMP system). It needs stressing that the existence of a surrounding membrane does not necessarily imply the existence of a gradient between the cytosol and the organelle lumen. For example, the nuclear membrane is highly permeable to both Ca2+ and cAMP (nuclear pores are permeable to solutes up to 50 kDa) and differences in [Ca2+] or [cAMP] between cytoplasm and nucleoplasm are not seen in steady state and only very transiently during cell activation. A similar situation has been observed, as far as Ca2+ is concerned, in peroxisomes.
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Affiliation(s)
- Riccardo Filadi
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Emy Basso
- Institute of Neuroscience, Padova Section, National Research Council, Padova, Italy
| | - Konstantinos Lefkimmiatis
- Institute of Neuroscience, Padova Section, National Research Council, Padova, Italy
- Venetian Institute of Molecular Medicine, Padova, Italy
| | - Tullio Pozzan
- Department of Biomedical Sciences, University of Padova, Padova, Italy.
- Institute of Neuroscience, Padova Section, National Research Council, Padova, Italy.
- Venetian Institute of Molecular Medicine, Padova, Italy.
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26
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Agarwal SR, Gratwohl J, Cozad M, Yang PC, Clancy CE, Harvey RD. Compartmentalized cAMP Signaling Associated With Lipid Raft and Non-raft Membrane Domains in Adult Ventricular Myocytes. Front Pharmacol 2018; 9:332. [PMID: 29740315 PMCID: PMC5925456 DOI: 10.3389/fphar.2018.00332] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 03/21/2018] [Indexed: 11/23/2022] Open
Abstract
Aim: Confining cAMP production to discrete subcellular locations makes it possible for this ubiquitous second messenger to elicit unique functional responses. Yet, factors that determine how and where the production of this diffusible signaling molecule occurs are incompletely understood. The fluid mosaic model originally proposed that signal transduction occurs through random interactions between proteins diffusing freely throughout the plasma membrane. However, it is now known that the movement of membrane proteins is restricted, suggesting that the plasma membrane is segregated into distinct microdomains where different signaling proteins can be concentrated. In this study, we examined what role lipid raft and non-raft membrane domains play in compartmentation of cAMP signaling in adult ventricular myocytes. Methods and Results: The freely diffusible fluorescence resonance energy transfer-based biosensor Epac2-camps was used to measure global cytosolic cAMP responses, while versions of the probe targeted to lipid raft (Epac2-MyrPalm) and non-raft (Epac2-CAAX) domains were used to monitor local cAMP production near the plasma membrane. We found that β-adrenergic receptors, which are expressed in lipid raft and non-raft domains, produce cAMP responses near the plasma membrane that are distinctly different from those produced by E-type prostaglandin receptors, which are expressed exclusively in non-raft domains. We also found that there are differences in basal cAMP levels associated with lipid raft and non-raft domains, and that this can be explained by differences in basal adenylyl cyclase activity associated with each of these membrane environments. In addition, we found evidence that phosphodiesterases 2, 3, and 4 work together in regulating cAMP activity associated with both lipid raft and non-raft domains, while phosphodiesterase 3 plays a more prominent role in the bulk cytoplasmic compartment. Conclusion: These results suggest that different membrane domains contribute to the formation of distinct pools of cAMP under basal conditions as well as following receptor stimulation in adult ventricular myocytes.
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Affiliation(s)
- Shailesh R Agarwal
- Department of Pharmacology, University of Nevada, Reno, Reno, NV, United States
| | - Jackson Gratwohl
- Department of Pharmacology, University of Nevada, Reno, Reno, NV, United States
| | - Mia Cozad
- Department of Pharmacology, University of Nevada, Reno, Reno, NV, United States
| | - Pei-Chi Yang
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Colleen E Clancy
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Robert D Harvey
- Department of Pharmacology, University of Nevada, Reno, Reno, NV, United States
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27
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Musheshe N, Schmidt M, Zaccolo M. cAMP: From Long-Range Second Messenger to Nanodomain Signalling. Trends Pharmacol Sci 2017; 39:209-222. [PMID: 29289379 DOI: 10.1016/j.tips.2017.11.006] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 11/14/2017] [Accepted: 11/17/2017] [Indexed: 12/21/2022]
Abstract
How cAMP generates hormone-specific effects has been debated for many decades. Fluorescence resonance energy transfer (FRET)-based sensors for cAMP allow real-time imaging of the second messenger in intact cells with high spatiotemporal resolution. This technology has made it possible to directly demonstrate that cAMP signals are compartmentalised. The details of such signal compartmentalisation are still being uncovered, and recent findings reveal a previously unsuspected submicroscopic heterogeneity of intracellular cAMP. A model is emerging where specificity depends on compartmentalisation and where the physiologically relevant signals are those that occur within confined nanodomains, rather than bulk changes in cytosolic cAMP. These findings subvert the classical notion of cAMP signalling and provide a new framework for the development of targeted therapeutic approaches.
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Affiliation(s)
- Nshunge Musheshe
- Department of Molecular Pharmacology, University of Groningen, The Netherlands; Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Martina Schmidt
- Department of Molecular Pharmacology, University of Groningen, The Netherlands; Groningen Research Institute for Asthma and COPD, GRIAC, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
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Agarwal SR, Miyashiro K, Latt H, Ostrom RS, Harvey RD. Compartmentalized cAMP responses to prostaglandin EP 2 receptor activation in human airway smooth muscle cells. Br J Pharmacol 2017; 174:2784-2796. [PMID: 28603838 DOI: 10.1111/bph.13904] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 05/25/2017] [Accepted: 06/05/2017] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE Previous studies indicate that prostaglandin EP2 receptors selectively couple to AC2 in non-lipid raft domains of airway smooth muscle (ASM) cells, where they regulate specific cAMP-dependent responses. The goal of the present study was to identify the cellular microdomains where EP2 receptors stimulate cAMP production. EXPERIMENTAL APPROACH FRET-based cAMP biosensors were targeted to different subcellular locations of primary human ASM cells. The Epac2-camps biosensor, which expresses throughout the cell, was used to measure bulk cytoplasmic responses. Epac2-MyrPalm and Epac2-CAAX were used to measure responses associated with lipid raft and non-raft regions of the plasma membrane respectively. Epac2-NLS was used to monitor responses at the nucleus. KEY RESULTS Activation of AC with forskolin or β2 -adrenoceptors with isoprenaline increased cAMP in all subcellular locations. Activation of EP2 receptors with butaprost produced cAMP responses that were most readily detected by the non-raft and nuclear sensors, but only weakly detected by the cytosolic sensor and not detected at all by the lipid raft sensor. Exposure to rolipram, a PDE4 inhibitor, unmasked the ability of EP2 receptors to increase cAMP levels associated with lipid raft domains. Overexpression of AC2 selectively increased EP2 receptor-stimulated production of cAMP in non-raft membrane domains. CONCLUSIONS AND IMPLICATIONS EP2 receptor activation of AC2 leads to cAMP production in non-raft and nuclear compartments of human ASMs, while β2 adrenoceptor signalling is broadly detected across microdomains. The activity of PDE4 appears to play a role in maintaining the integrity of compartmentalized EP2 receptor responses in these cells.
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Affiliation(s)
- Shailesh R Agarwal
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Kathryn Miyashiro
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Htun Latt
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Rennolds S Ostrom
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA, USA
| | - Robert D Harvey
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, USA
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Lohse C, Bock A, Maiellaro I, Hannawacker A, Schad LR, Lohse MJ, Bauer WR. Experimental and mathematical analysis of cAMP nanodomains. PLoS One 2017; 12:e0174856. [PMID: 28406920 PMCID: PMC5391016 DOI: 10.1371/journal.pone.0174856] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 03/16/2017] [Indexed: 12/13/2022] Open
Abstract
In their role as second messengers, cyclic nucleotides such as cAMP have a variety of intracellular effects. These complex tasks demand a highly organized orchestration of spatially and temporally confined cAMP action which should be best achieved by compartmentalization of the latter. A great body of evidence suggests that cAMP compartments may be established and maintained by cAMP degrading enzymes, e.g. phosphodiesterases (PDEs). However, the molecular and biophysical details of how PDEs can orchestrate cAMP gradients are entirely unclear. In this paper, using fusion proteins of cAMP FRET-sensors and PDEs in living cells, we provide direct experimental evidence that the cAMP concentration in the vicinity of an individual PDE molecule is below the detection limit of our FRET sensors (<100nM). This cAMP gradient persists in crude cytosol preparations. We developed mathematical models based on diffusion-reaction equations which describe the creation of nanocompartments around a single PDE molecule and more complex spatial PDE arrangements. The analytically solvable equations derived here explicitly determine how the capability of a single PDE, or PDE complexes, to create a nanocompartment depend on the cAMP degradation rate, the diffusive mobility of cAMP, and geometrical and topological parameters. We apply these generic models to our experimental data and determine the diffusive mobility and degradation rate of cAMP. The results obtained for these parameters differ by far from data in literature for free soluble cAMP interacting with PDE. Hence, restricted cAMP diffusion in the vincinity of PDE is necessary to create cAMP nanocompartments in cells.
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Affiliation(s)
- Christian Lohse
- Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
- Computer Assisted Clinical Medicine, University of Heidelberg, Heidelberg, Germany
| | - Andreas Bock
- Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
| | - Isabella Maiellaro
- Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
| | - Annette Hannawacker
- Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
| | - Lothar R. Schad
- Computer Assisted Clinical Medicine, University of Heidelberg, Heidelberg, Germany
| | - Martin J. Lohse
- Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
- Comprehensive Heart Failure Center, University of Würzburg, Würzburg, Germany
- * E-mail:
| | - Wolfgang R. Bauer
- Comprehensive Heart Failure Center, University of Würzburg, Würzburg, Germany
- Department of Medicine I, University Hospital Würzburg, Würzburg, Germany
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Sukhanova IF, Kozhevnikova LM, Mironova GY, Avdonin PV. The Epac protein inhibitor ESI-09 eliminates the tonic phase of aorta contraction induced by endogenic vasoconstrictors in rats. BIOL BULL+ 2017. [DOI: 10.1134/s1062359017020200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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32
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Bedioune I, Bobin P, Leroy J, Fischmeister R, Vandecasteele G. Cyclic Nucleotide Phosphodiesterases and Compartmentation in Normal and Diseased Heart. MICRODOMAINS IN THE CARDIOVASCULAR SYSTEM 2017. [DOI: 10.1007/978-3-319-54579-0_6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Pendin D, Greotti E, Lefkimmiatis K, Pozzan T. Exploring cells with targeted biosensors. J Gen Physiol 2016; 149:1-36. [PMID: 28028123 PMCID: PMC5217087 DOI: 10.1085/jgp.201611654] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 10/26/2016] [Accepted: 12/01/2016] [Indexed: 01/10/2023] Open
Abstract
Cellular signaling networks are composed of multiple pathways, often interconnected, that form complex networks with great potential for cross-talk. Signal decoding depends on the nature of the message as well as its amplitude, temporal pattern, and spatial distribution. In addition, the existence of membrane-bound organelles, which are both targets and generators of messages, add further complexity to the system. The availability of sensors that can localize to specific compartments in live cells and monitor their targets with high spatial and temporal resolution is thus crucial for a better understanding of cell pathophysiology. For this reason, over the last four decades, a variety of strategies have been developed, not only to generate novel and more sensitive probes for ions, metabolites, and enzymatic activity, but also to selectively deliver these sensors to specific intracellular compartments. In this review, we summarize the principles that have been used to target organic or protein sensors to different cellular compartments and their application to cellular signaling.
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Affiliation(s)
- Diana Pendin
- Neuroscience Institute, National Research Council, Padua Section, 35121 Padua, Italy.,Department of Biomedical Sciences, University of Padua, 35121 Padua, Italy
| | - Elisa Greotti
- Neuroscience Institute, National Research Council, Padua Section, 35121 Padua, Italy.,Department of Biomedical Sciences, University of Padua, 35121 Padua, Italy
| | - Konstantinos Lefkimmiatis
- Neuroscience Institute, National Research Council, Padua Section, 35121 Padua, Italy.,Venetian Institute of Molecular Medicine, 35129 Padua, Italy
| | - Tullio Pozzan
- Neuroscience Institute, National Research Council, Padua Section, 35121 Padua, Italy.,Venetian Institute of Molecular Medicine, 35129 Padua, Italy.,Department of Biomedical Sciences, University of Padua, 35121 Padua, Italy
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Yang PC, Boras BW, Jeng MT, Docken SS, Lewis TJ, McCulloch AD, Harvey RD, Clancy CE. A Computational Modeling and Simulation Approach to Investigate Mechanisms of Subcellular cAMP Compartmentation. PLoS Comput Biol 2016; 12:e1005005. [PMID: 27409243 PMCID: PMC4943723 DOI: 10.1371/journal.pcbi.1005005] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 05/26/2016] [Indexed: 11/18/2022] Open
Abstract
Subcellular compartmentation of the ubiquitous second messenger cAMP has been widely proposed as a mechanism to explain unique receptor-dependent functional responses. How exactly compartmentation is achieved, however, has remained a mystery for more than 40 years. In this study, we developed computational and mathematical models to represent a subcellular sarcomeric space in a cardiac myocyte with varying detail. We then used these models to predict the contributions of various mechanisms that establish subcellular cAMP microdomains. We used the models to test the hypothesis that phosphodiesterases act as functional barriers to diffusion, creating discrete cAMP signaling domains. We also used the models to predict the effect of a range of experimentally measured diffusion rates on cAMP compartmentation. Finally, we modeled the anatomical structures in a cardiac myocyte diad, to predict the effects of anatomical diffusion barriers on cAMP compartmentation. When we incorporated experimentally informed model parameters to reconstruct an in silico subcellular sarcomeric space with spatially distinct cAMP production sites linked to caveloar domains, the models predict that under realistic conditions phosphodiesterases alone were insufficient to generate significant cAMP gradients. This prediction persisted even when combined with slow cAMP diffusion. When we additionally considered the effects of anatomic barriers to diffusion that are expected in the cardiac myocyte dyadic space, cAMP compartmentation did occur, but only when diffusion was slow. Our model simulations suggest that additional mechanisms likely contribute to cAMP gradients occurring in submicroscopic domains. The difference between the physiological and pathological effects resulting from the production of cAMP may be a function of appropriate compartmentation of cAMP signaling. Therefore, understanding the contribution of factors that are responsible for coordinating the spatial and temporal distribution of cAMP at the subcellular level could be important for developing new strategies for the prevention or treatment of unfavorable responses associated with different disease states. Subcellular compartmentation of the ubiquitous second messenger cAMP has been widely proposed as a mechanism to explain how this one signaling molecule produces unique receptor-dependent functional responses. But, how exactly compartmentation occurs, is unknown. This is because there has been no way to measure the regulation and movement of cAMP in cells with intact subcellular structures. In this study, we applied novel computational approaches to predict whether PDE activity alone or in conjunction with restricted diffusion is sufficient to produce cAMP gradients in submicroscopic signaling domains. We also used the models to test the effect of a range of experimentally measured diffusion rates on cAMP compartmentation. Our simulations suggest that PDE activity alone is not sufficient to explain compartmentation, but if diffusion of cAMP is limited by potential factors such as molecular crowding, PKA buffering, and anatomical barriers, then compartmentation is predicted to occur.
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Affiliation(s)
- Pei-Chi Yang
- Department of Pharmacology, University of California Davis, Davis, California, United States of America
| | - Britton W. Boras
- Department of Biomedical Engineering, University of California San Diego, La Jolla, California, United States of America
| | - Mao-Tsuen Jeng
- Department of Pharmacology, University of California Davis, Davis, California, United States of America
| | - Steffen S. Docken
- Department of Pharmacology, University of California Davis, Davis, California, United States of America
- Department of Mathematics, University of California Davis, Davis, California, United States of America
| | - Timothy J. Lewis
- Department of Mathematics, University of California Davis, Davis, California, United States of America
- * E-mail: (TJL); (ADM); (RDH); (CEC)
| | - Andrew D. McCulloch
- Department of Biomedical Engineering, University of California San Diego, La Jolla, California, United States of America
- * E-mail: (TJL); (ADM); (RDH); (CEC)
| | - Robert D. Harvey
- Department of Pharmacology, Center for Molecular Medicine, School of Medicine, University of Nevada Reno, Reno, Nevada, United States of America
- * E-mail: (TJL); (ADM); (RDH); (CEC)
| | - Colleen E. Clancy
- Department of Pharmacology, University of California Davis, Davis, California, United States of America
- * E-mail: (TJL); (ADM); (RDH); (CEC)
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35
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A Computational Modeling and Simulation Approach to Investigate Mechanisms of Subcellular cAMP Compartmentation. PLoS Comput Biol 2016. [DOI: 10.1371/journal.pcbi.1005005 pcompbiol-d-16-00287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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36
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Richards M, Lomas O, Jalink K, Ford KL, Vaughan-Jones RD, Lefkimmiatis K, Swietach P. Intracellular tortuosity underlies slow cAMP diffusion in adult ventricular myocytes. Cardiovasc Res 2016; 110:395-407. [PMID: 27089919 PMCID: PMC4872880 DOI: 10.1093/cvr/cvw080] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 04/11/2016] [Indexed: 12/20/2022] Open
Abstract
Aims 3′,5′-Cyclic adenosine monophosphate (cAMP) signals in the heart are often confined to concentration microdomains shaped by cAMP diffusion and enzymatic degradation. While the importance of phosphodiesterases (degradative enzymes) in sculpting cAMP microdomains is well established in cardiomyocytes, less is known about cAMP diffusivity (DcAMP) and factors affecting it. Many earlier studies have reported fast diffusivity, which argues against sharply defined microdomains. Methods and results [cAMP] dynamics in the cytoplasm of adult rat ventricular myocytes were imaged using a fourth generation genetically encoded FRET-based sensor. The [cAMP]-response to the addition and removal of isoproterenol (β-adrenoceptor agonist) quantified the rates of cAMP synthesis and degradation. To obtain a read out of DcAMP, a stable [cAMP] gradient was generated using a microfluidic device which delivered agonist to one half of the myocyte only. After accounting for phosphodiesterase activity, DcAMP was calculated to be 32 µm2/s; an order of magnitude lower than in water. Diffusivity was independent of the amount of cAMP produced. Saturating cAMP-binding sites with the analogue 6-Bnz-cAMP did not accelerate DcAMP, arguing against a role of buffering in restricting cAMP mobility. cAMP diffused at a comparable rate to chemically unrelated but similar sized molecules, arguing for a common physical cause of restricted diffusivity. Lower mitochondrial density and order in neonatal cardiac myocytes allowed for faster diffusion, demonstrating the importance of mitochondria as physical barriers to cAMP mobility. Conclusion In adult cardiac myocytes, tortuosity due to physical barriers, notably mitochondria, restricts cAMP diffusion to levels that are more compatible with microdomain signalling.
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Affiliation(s)
- Mark Richards
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
| | - Oliver Lomas
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
| | - Kees Jalink
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands
| | - Kerrie L Ford
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
| | - Richard D Vaughan-Jones
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
| | - Konstantinos Lefkimmiatis
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK BHF Centre of Research Excellence, Oxford
| | - Pawel Swietach
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
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37
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Agarwal SR, Clancy CE, Harvey RD. Mechanisms Restricting Diffusion of Intracellular cAMP. Sci Rep 2016; 6:19577. [PMID: 26795432 PMCID: PMC4726171 DOI: 10.1038/srep19577] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 12/11/2015] [Indexed: 01/11/2023] Open
Abstract
Although numerous receptors stimulate cAMP production in a wide array of cells, many elicit distinct, highly localized responses, implying that the subcellular distribution of cAMP is not uniform. One often used explanation is that phosphodiesterases, which breakdown cAMP, act as functional barriers limiting diffusion. However, several studies refute the notion that this is sufficient, suggesting that phosphodiesterase-independent movement of cAMP must occur at rates slower than free diffusion. But, until now this has never been demonstrated. Using Raster Image Correlation Spectroscopy (RICS), we measured the diffusion coefficient of a fluorescently-labeled cAMP derivative (φ450-cAMP) as well as other fluorescent molecules in order to investigate the role that molecular size, cell morphology, and buffering by protein kinase A (PKA) play in restricting cAMP mobility in different cell types. Our results demonstrate that cytosolic movement of cAMP is indeed much slower than the rate of free diffusion and that interactions with PKA, especially type II PKA associated with mitochondria, play a significant role. These findings have important implications with respect to cAMP signaling in all cells.
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Affiliation(s)
- Shailesh R Agarwal
- Department of Pharmacology University of Nevada School of Medicine Reno, NV 89557
| | - Colleen E Clancy
- Department of Pharmacology University of California, Davis Davis, CA 95616
| | - Robert D Harvey
- Department of Pharmacology University of Nevada School of Medicine Reno, NV 89557
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38
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Leavesley SJ, Nakhmani A, Gao Y, Rich TC. Automated image analysis of FRET signals for subcellular cAMP quantification. Methods Mol Biol 2015; 1294:59-70. [PMID: 25783877 DOI: 10.1007/978-1-4939-2537-7_5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A variety of FRET probes have been developed to examine cAMP localization and dynamics in single cells. These probes offer a readily accessible approach to measure localized cAMP signals. However, given the low signal-to-noise ratio of most FRET probes and the dynamic nature of the intracellular environment, there have been marked limitations in the ability to use FRET probes to study localized signaling events within the same cell. Here, we outline a methodology to dissect kinetics of cAMP-mediated FRET signals in single cells using automated image analysis approaches. We additionally extend these approaches to the analysis of subcellular regions. These approaches offer an unique opportunity to assess localized cAMP kinetics in an unbiased, quantitative fashion.
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Affiliation(s)
- Silas J Leavesley
- Department of Chemical and Biomolecular Engineering, University of South Alabama, 150 Jaguar Drive, SH 4129, Mobile, AL, 36688, USA,
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Neves-Zaph SR, Song RS. Development of computational models of cAMP signaling. Methods Mol Biol 2015; 1294:203-17. [PMID: 25783888 DOI: 10.1007/978-1-4939-2537-7_16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Despite the growing evidence defining the cAMP signaling network as a master regulator of cellular function in a number of tissues, regulatory feedback loops, signal compartmentalization, as well as cross-talk with other signaling pathways make understanding the emergent properties of cAMP cellular action a daunting task. Dynamical models of signaling that combine quantitative rigor with molecular details can contribute valuable mechanistic insight into the complexity of intracellular cAMP signaling by complementing and guiding experimental efforts. In this chapter, we review the development of cAMP computational models. We describe how features of the cAMP network can be represented and review the types of experimental data useful in modeling cAMP signaling. We also compile a list of published cAMP models that can aid in the development of novel dynamical models of cAMP signaling.
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Affiliation(s)
- Susana R Neves-Zaph
- Department of Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA,
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40
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Xin W, Feinstein WP, Britain AL, Ochoa CD, Zhu B, Richter W, Leavesley SJ, Rich TC. Estimating the magnitude of near-membrane PDE4 activity in living cells. Am J Physiol Cell Physiol 2015. [PMID: 26201952 DOI: 10.1152/ajpcell.00090.2015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Recent studies have demonstrated that functionally discrete pools of phosphodiesterase (PDE) activity regulate distinct cellular functions. While the importance of localized pools of enzyme activity has become apparent, few studies have estimated enzyme activity within discrete subcellular compartments. Here we present an approach to estimate near-membrane PDE activity. First, total PDE activity is measured using traditional PDE activity assays. Second, known cAMP concentrations are dialyzed into single cells and the spatial spread of cAMP is monitored using cyclic nucleotide-gated channels. Third, mathematical models are used to estimate the spatial distribution of PDE activity within cells. Using this three-tiered approach, we observed two pharmacologically distinct pools of PDE activity, a rolipram-sensitive pool and an 8-methoxymethyl IBMX (8MM-IBMX)-sensitive pool. We observed that the rolipram-sensitive PDE (PDE4) was primarily responsible for cAMP hydrolysis near the plasma membrane. Finally, we observed that PDE4 was capable of blunting cAMP levels near the plasma membrane even when 100 μM cAMP were introduced into the cell via a patch pipette. Two compartment models predict that PDE activity near the plasma membrane, near cyclic nucleotide-gated channels, was significantly lower than total cellular PDE activity and that a slow spatial spread of cAMP allowed PDE activity to effectively hydrolyze near-membrane cAMP. These results imply that cAMP levels near the plasma membrane are distinct from those in other subcellular compartments; PDE activity is not uniform within cells; and localized pools of AC and PDE activities are responsible for controlling cAMP levels within distinct subcellular compartments.
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Affiliation(s)
- Wenkuan Xin
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina
| | - Wei P Feinstein
- High Performance Computing, Louisiana State University, Baton Rouge, Louisiana
| | - Andrea L Britain
- Department of Pharmacology, University of South Alabama, Mobile, Alabama; and Center for Lung Biology, University of South Alabama, Mobile, Alabama
| | - Cristhiaan D Ochoa
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Bing Zhu
- Mitchell Cancer Institute, Mobile, Alabama
| | - Wito Richter
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama; Center for Lung Biology, University of South Alabama, Mobile, Alabama
| | - Silas J Leavesley
- Department of Chemical and Biomolecular Engineering, University of South Alabama, Mobile, Alabama; Department of Pharmacology, University of South Alabama, Mobile, Alabama; and Center for Lung Biology, University of South Alabama, Mobile, Alabama
| | - Thomas C Rich
- Department of Pharmacology, University of South Alabama, Mobile, Alabama; and Center for Lung Biology, University of South Alabama, Mobile, Alabama
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41
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Poppinga WJ, Muñoz-Llancao P, González-Billault C, Schmidt M. A-kinase anchoring proteins: cAMP compartmentalization in neurodegenerative and obstructive pulmonary diseases. Br J Pharmacol 2014; 171:5603-23. [PMID: 25132049 PMCID: PMC4290705 DOI: 10.1111/bph.12882] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 07/14/2014] [Accepted: 08/10/2014] [Indexed: 12/25/2022] Open
Abstract
The universal second messenger cAMP is generated upon stimulation of Gs protein-coupled receptors, such as the β2 -adreneoceptor, and leads to the activation of PKA, the major cAMP effector protein. PKA oscillates between an on and off state and thereby regulates a plethora of distinct biological responses. The broad activation pattern of PKA and its contribution to several distinct cellular functions lead to the introduction of the concept of compartmentalization of cAMP. A-kinase anchoring proteins (AKAPs) are of central importance due to their unique ability to directly and/or indirectly interact with proteins that either determine the cellular content of cAMP, such as β2 -adrenoceptors, ACs and PDEs, or are regulated by cAMP such as the exchange protein directly activated by cAMP. We report on lessons learned from neurons indicating that maintenance of cAMP compartmentalization by AKAP5 is linked to neurotransmission, learning and memory. Disturbance of cAMP compartments seem to be linked to neurodegenerative disease including Alzheimer's disease. We translate this knowledge to compartmentalized cAMP signalling in the lung. Next to AKAP5, we focus here on AKAP12 and Ezrin (AKAP78). These topics will be highlighted in the context of the development of novel pharmacological interventions to tackle AKAP-dependent compartmentalization.
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Affiliation(s)
- W J Poppinga
- Department of Molecular Pharmacology, University of GroningenGroningen, The Netherlands
- Groningen Research Institute for Asthma and COPD (GRIAC), University Medical Center Groningen, University of GroningenGroningen, The Netherlands
| | - P Muñoz-Llancao
- Department of Molecular Pharmacology, University of GroningenGroningen, The Netherlands
- Laboratory of Cell and Neuronal Dynamics (Cenedyn), Department of Biology, Faculty of Sciences, Universidad de ChileSantiago, Chile
- Department of Neuroscience, Section Medical Physiology, University Medical Center Groningen, University of GroningenGroningen, The Netherlands
| | - C González-Billault
- Laboratory of Cell and Neuronal Dynamics (Cenedyn), Department of Biology, Faculty of Sciences, Universidad de ChileSantiago, Chile
| | - M Schmidt
- Department of Molecular Pharmacology, University of GroningenGroningen, The Netherlands
- Groningen Research Institute for Asthma and COPD (GRIAC), University Medical Center Groningen, University of GroningenGroningen, The Netherlands
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Calebiro D, Maiellaro I. cAMP signaling microdomains and their observation by optical methods. Front Cell Neurosci 2014; 8:350. [PMID: 25389388 PMCID: PMC4211404 DOI: 10.3389/fncel.2014.00350] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 10/07/2014] [Indexed: 11/22/2022] Open
Abstract
The second messenger cyclic AMP (cAMP) is a major intracellular mediator of many hormones and neurotransmitters and regulates a myriad of cell functions, including synaptic plasticity in neurons. Whereas cAMP can freely diffuse in the cytosol, a growing body of evidence suggests the formation of cAMP gradients and microdomains near the sites of cAMP production, where cAMP signals remain apparently confined. The mechanisms responsible for the formation of such microdomains are subject of intensive investigation. The development of optical methods based on fluorescence resonance energy transfer (FRET), which allow a direct observation of cAMP signaling with high temporal and spatial resolution, is playing a fundamental role in elucidating the nature of such microdomains. Here, we will review the optical methods used for monitoring cAMP and protein kinase A (PKA) signaling in living cells, providing some examples of their application in neurons, and will discuss the major hypotheses on the formation of cAMP/PKA microdomains.
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Affiliation(s)
- Davide Calebiro
- Institute of Pharmacology and Toxicology, University of Würzburg Würzburg, Germany ; Bio-Imaging Center/Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg Würzburg, Germany
| | - Isabella Maiellaro
- Institute of Pharmacology and Toxicology, University of Würzburg Würzburg, Germany ; Bio-Imaging Center/Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg Würzburg, Germany
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43
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Lefkimmiatis K, Zaccolo M. cAMP signaling in subcellular compartments. Pharmacol Ther 2014; 143:295-304. [PMID: 24704321 PMCID: PMC4117810 DOI: 10.1016/j.pharmthera.2014.03.008] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 03/24/2014] [Indexed: 01/11/2023]
Abstract
In the complex microcosm of a cell, information security and its faithful transmission are critical for maintaining internal stability. To achieve a coordinated response of all its parts to any stimulus the cell must protect the information received from potentially confounding signals. Physical segregation of the information transmission chain ensures that only the entities able to perform the encoded task have access to the relevant information. The cAMP intracellular signaling pathway is an important system for signal transmission responsible for the ancestral 'flight or fight' response and involved in the control of critical functions including frequency and strength of heart contraction, energy metabolism and gene transcription. It is becoming increasingly apparent that the cAMP signaling pathway uses compartmentalization as a strategy for coordinating the large number of key cellular functions under its control. Spatial confinement allows the formation of cAMP signaling "hot spots" at discrete subcellular domains in response to specific stimuli, bringing the information in proximity to the relevant effectors and their recipients, thus achieving specificity of action. In this report we discuss how the different constituents of the cAMP pathway are targeted and participate in the formation of cAMP compartmentalized signaling events. We illustrate a few examples of localized cAMP signaling, with a particular focus on the nucleus, the sarcoplasmic reticulum and the mitochondria. Finally, we discuss the therapeutic potential of interventions designed to perturb specific cAMP cascades locally.
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Affiliation(s)
| | - Manuela Zaccolo
- Department Of Physiology, Anatomy & Genetics, University of Oxford, UK.
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44
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Saucerman JJ, Greenwald EC, Polanowska-Grabowska R. Mechanisms of cyclic AMP compartmentation revealed by computational models. ACTA ACUST UNITED AC 2014; 143:39-48. [PMID: 24378906 PMCID: PMC3874575 DOI: 10.1085/jgp.201311044] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Jeffrey J Saucerman
- Department of Biomedical Engineering and Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908
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45
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Conti M, Mika D, Richter W. Cyclic AMP compartments and signaling specificity: role of cyclic nucleotide phosphodiesterases. ACTA ACUST UNITED AC 2014; 143:29-38. [PMID: 24378905 PMCID: PMC3874571 DOI: 10.1085/jgp.201311083] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Marco Conti
- Center for Reproductive Sciences, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, San Francisco, CA 94143
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46
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Karpen JW. Perspectives on: Cyclic nucleotide microdomains and signaling specificity. ACTA ACUST UNITED AC 2014; 143:5-7. [PMID: 24378902 PMCID: PMC3874568 DOI: 10.1085/jgp.201311144] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Jeffrey W Karpen
- Department of Medical Education, California Northstate University College of Medicine, Elk Grove, CA 95757
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47
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Ligand-selective activation of heterologously-expressed mammalian olfactory receptor. Cell Calcium 2014; 56:245-56. [PMID: 25149566 DOI: 10.1016/j.ceca.2014.07.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 07/24/2014] [Accepted: 07/27/2014] [Indexed: 11/23/2022]
Abstract
Mammalian olfactory receptors (ORs) appear to have the capacity to couple to multiple G protein-coupled signaling pathways in a ligand-dependent selective manner. To better understand the mechanisms and molecular range of such ligand selectivity, we expressed the mouse eugenol OR (mOR-EG) in HEK293T cells together with Gα15 to monitor activation of the phospholipase-C (PLC) signaling pathway and/or Gαolf to monitor activation of the adenylate cyclase (AC) signaling pathway, resulting in intracellular Ca(2+) release and/or Ca(2+) influx through a cyclic nucleotide-gated channel, respectively. PLC-dependent responses differed dynamically from AC-dependent responses, allowing them to be distinguished when Gα15 and Gαolf were co-expressed. The dynamic difference in readout was independent of the receptor, the heterologous expression system, and the ligand concentration. Of 17 reported mOR-EG ligands tested, including eugenol, its analogs, and structurally dissimilar compounds (mousse cristal, nootkatone, orivone), some equally activated both signaling pathways, some differentially activated both signaling pathways, and some had no noticeable effect even at 1-5mM. Our findings argue that mOR-EG, when heterologously expressed, can couple to two different signaling pathways in a ligand selective manner. The challenge now is to determine the potential of mOR-EG, and perhaps other ORs, to activate multiple signaling pathways in a ligand selective manner in native ORNs.
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48
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Formosa R, Vassallo J. cAMP signalling in the normal and tumorigenic pituitary gland. Mol Cell Endocrinol 2014; 392:37-50. [PMID: 24845420 DOI: 10.1016/j.mce.2014.05.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 05/04/2014] [Accepted: 05/05/2014] [Indexed: 01/06/2023]
Abstract
cAMP signalling plays a key role in the normal physiology of the pituitary gland, regulating cellular growth and proliferation, hormone production and release. Deregulation of the cAMP signalling pathway has been reported to be a common occurrence in pituitary tumorigenesis. Several mechanisms have been implicated including somatic mutations, gene-gene interactions and gene-environmental interactions. Somatic mutations in G-proteins and protein kinases directly alter cAMP signalling, while malfunctioning of other signalling pathways such as the Raf/MAPK/ERK, PI3K/Akt/mTOR and Wnt pathways which normally interact with the cAMP pathway may mediate indirect effects on cAMP and varying downstream effectors. The aryl hydrocarbon receptor signalling pathway has been implicated in pituitary tumorigenesis and we review its role in general and specifically in relation to cAMP de-regulation.
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Affiliation(s)
- R Formosa
- Department of Medicine, Faculty of Medicine and Surgery, University of Malta, Level 0, Block A, Mater Dei Hospital, Msida MSD2080, Malta.
| | - J Vassallo
- Department of Medicine, Faculty of Medicine and Surgery, University of Malta, Level 0, Block A, Mater Dei Hospital, Msida MSD2080, Malta.
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49
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Otero C, Peñaloza JP, Rodas PI, Fernández-Ramires R, Velasquez L, Jung JE. Temporal and spatial regulation of cAMP signaling in disease: role of cyclic nucleotide phosphodiesterases. Fundam Clin Pharmacol 2014; 28:593-607. [PMID: 24750474 DOI: 10.1111/fcp.12080] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 03/28/2014] [Accepted: 04/17/2014] [Indexed: 01/19/2023]
Abstract
Since its discovery, cAMP has been proposed as one of the most versatile second messengers. The remarkable feature of cAMP to tightly control highly diverse physiological processes, including metabolism, homeostasis, secretion, muscle contraction, cell proliferation and migration, immune response, and gene transcription, is reflected by millions of different articles worldwide. Compartmentalization of cAMP in space and time, maintained by mainly phosphodiesterases, contributes to the maintenance of equilibrium inside the cell where one signal can trigger many different events. Novel cAMP sensors seem to carry out certain unexpected signaling properties of cAMP and thereby to permit delicate adaptations of biologic responses. Measuring space and time events with biosensors will increase our current knowledge on the pathophysiology of diseases, such as chronic obstructive pulmonary disease, asthma, cognitive impairment, cancer, and renal and heart failure. Further insights into the cAMP dynamics will help to optimize the pharmacological treatment for these diseases.
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Affiliation(s)
- Carolina Otero
- Center for Integrative Medicine and Innovative Science, Universidad Andres Bello, Santiago, Chile; Centro para el Desarrollo de la Nanociencia y Nanotecnologia, Santiago, Chile
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50
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McCormick K, Baillie GS. Compartmentalisation of second messenger signalling pathways. Curr Opin Genet Dev 2014; 27:20-5. [PMID: 24791689 DOI: 10.1016/j.gde.2014.02.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 02/21/2014] [Accepted: 02/22/2014] [Indexed: 01/21/2023]
Abstract
The ability of a cell to transform an extracellular stimulus into a downstream event that directs specific physiological outcomes, requires the orchestrated, spatial and temporal response of many signalling proteins. The notion of compartmentalised signalling pathways was popularised in the 1980s by Brunton and colleagues, with their discovery that spatially segregated cAMP directs a variety of signalling responses in cardiomyocytes. It is now understood that compartmentalisation is a common mechanism used by all cells to ensure the interaction of signalling 'second messenger' molecules with localised 'pools' of appropriate effector proteins. In this way, the cell can elicit differential cellular responses by using a single, freely diffusible, molecular species. Recently, the compartmentalisation schemes employed by signalling systems involving cyclic nucleotides, calcium and nitric oxide have been elucidated and as a result, the varied range of functional consequences underpinned by such strategies can be better appreciated.
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Affiliation(s)
- Kristie McCormick
- Institute of Cardiovascular and Medical Sciences, CMVLS, Wolfson-Link Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - George S Baillie
- Institute of Cardiovascular and Medical Sciences, CMVLS, Wolfson-Link Building, University of Glasgow, Glasgow G12 8QQ, UK.
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