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Bastola T, Perkins GA, Huu VAN, Ju S, Kim KY, Shen Z, Skowronska-Krawczyk D, Weinreb RN, Ju WK. Administration of Bicarbonate Protects Mitochondria, Rescues Retinal Ganglion Cells, and Ameliorates Visual Dysfunction Caused by Oxidative Stress. Antioxidants (Basel) 2024; 13:743. [PMID: 38929182 PMCID: PMC11200884 DOI: 10.3390/antiox13060743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Revised: 06/11/2024] [Accepted: 06/17/2024] [Indexed: 06/28/2024] Open
Abstract
Oxidative stress is a key factor causing mitochondrial dysfunction and retinal ganglion cell (RGC) death in glaucomatous neurodegeneration. The cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling pathway is involved in mitochondrial protection, promoting RGC survival. Soluble adenylyl cyclase (sAC) is a key regulator of the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling pathway, which is known to protect mitochondria and promote RGC survival. However, the precise molecular mechanisms connecting the sAC-mediated signaling pathway with mitochondrial protection in RGCs against oxidative stress are not well characterized. Here, we demonstrate that sAC plays a critical role in protecting RGC mitochondria from oxidative stress. Using mouse models of oxidative stress induced by ischemic injury and paraquat administration, we found that administration of bicarbonate, as an activator of sAC, protected RGCs, blocked AMP-activated protein kinase activation, inhibited glial activation, and improved visual function. Moreover, we found that this is the result of preserving mitochondrial dynamics (fusion and fission), promoting mitochondrial bioenergetics and biogenesis, and preventing metabolic stress and apoptotic cell death. Notably, the administration of bicarbonate ameliorated mitochondrial dysfunction in RGCs by enhancing mitochondrial biogenesis, preserving mitochondrial structure, and increasing ATP production in oxidatively stressed RGCs. These findings suggest that activating sAC enhances the mitochondrial structure and function in RGCs to counter oxidative stress, consequently promoting RGC protection. We propose that modulation of the sAC-mediated signaling pathway has therapeutic potential acting on RGC mitochondria for treating glaucoma and other retinal diseases.
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Affiliation(s)
- Tonking Bastola
- Hamilton Glaucoma Center and Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (V.A.N.H.); (Z.S.); (R.N.W.)
| | - Guy A. Perkins
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA (S.J.); (K.-Y.K.)
| | - Viet Anh Nguyen Huu
- Hamilton Glaucoma Center and Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (V.A.N.H.); (Z.S.); (R.N.W.)
| | - Saeyeon Ju
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA (S.J.); (K.-Y.K.)
| | - Keun-Young Kim
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA (S.J.); (K.-Y.K.)
| | - Ziyao Shen
- Hamilton Glaucoma Center and Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (V.A.N.H.); (Z.S.); (R.N.W.)
| | - Dorota Skowronska-Krawczyk
- Center for Translational Vision Research, Department of Physiology, Biophysics & Ophthalmology, University of California Irvine, Irvine, CA 92697, USA;
| | - Robert N. Weinreb
- Hamilton Glaucoma Center and Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (V.A.N.H.); (Z.S.); (R.N.W.)
| | - Won-Kyu Ju
- Hamilton Glaucoma Center and Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (V.A.N.H.); (Z.S.); (R.N.W.)
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2
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Bastola T, Perkins GA, Huu VAN, Ju S, Kim KY, Shen Z, Skowronska-Krawczyk D, Weinreb RN, Ju WK. Activating soluble adenylyl cyclase protects mitochondria, rescues retinal ganglion cells, and ameliorates visual dysfunction caused by oxidative stress. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.04.583371. [PMID: 38496531 PMCID: PMC10942326 DOI: 10.1101/2024.03.04.583371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Oxidative stress is a key factor causing mitochondrial dysfunction and retinal ganglion cell (RGC) death in glaucomatous neurodegeneration. The cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling pathway is involved in mitochondrial protection, promoting RGC survival. Soluble adenylyl cyclase (sAC) is one of the key regulators of the cAMP/PKA signaling pathway. However, the precise molecular mechanisms underlying the sAC-mediated signaling pathway and mitochondrial protection in RGCs that counter oxidative stress are not well characterized. Here, we demonstrate that sAC plays a critical role in protecting RGC mitochondria from oxidative stress. Using mouse models of oxidative stress, we found that activating sAC protected RGCs, blocked AMP-activated protein kinase activation, inhibited glial activation, and improved visual function. Moreover, we found that this is the result of preserving mitochondrial dynamics (fusion and fission), promoting mitochondrial bioenergetics and biogenesis, and preventing metabolic stress and apoptotic cell death in a paraquat oxidative stress model. Notably, sAC activation ameliorated mitochondrial dysfunction in RGCs by enhancing mitochondrial biogenesis, preserving mitochondrial structure, and increasing ATP production in oxidatively stressed RGCs. These findings suggest that activating sAC enhances the mitochondrial structure and function in RGCs to counter oxidative stress, consequently promoting RGC protection. We propose that modulation of the sAC-mediated signaling pathway has therapeutic potential acting on RGC mitochondria for treating glaucoma and other retinal diseases.
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3
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Paolocci E, Zaccolo M. Compartmentalised cAMP signalling in the primary cilium. Front Physiol 2023; 14:1187134. [PMID: 37256063 PMCID: PMC10226274 DOI: 10.3389/fphys.2023.1187134] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 04/25/2023] [Indexed: 06/01/2023] Open
Abstract
cAMP is a universal second messenger that relies on precise spatio-temporal regulation to control varied, and often opposing, cellular functions. This is achieved via selective activation of effectors embedded in multiprotein complexes, or signalosomes, that reside at distinct subcellular locations. cAMP is also one of many pathways known to operate within the primary cilium. Dysfunction of ciliary signaling leads to a class of diseases known as ciliopathies. In Autosomal Dominant Polycystic Kidney Disease (ADPKD), a ciliopathy characterized by the formation of fluid-filled kidney cysts, upregulation of cAMP signaling is known to drive cystogenesis. For decades it has been debated whether the primary cilium is an independent cAMP sub-compartment, or whether it shares a diffusible pool of cAMP with the cell body. Recent studies now suggest it is a specific pool of cAMP generated in the cilium that propels cyst formation in ADPKD, supporting the notion that this antenna-like organelle is a compartment within which cAMP signaling occurs independently from cAMP signaling in the bulk cytosol. Here we present examples of cAMP function in the cilium which suggest this mysterious organelle is home to more than one cAMP signalosome. We review evidence that ciliary membrane localization of G-Protein Coupled Receptors (GPCRs) determines their downstream function and discuss how optogenetic tools have contributed to establish that cAMP generated in the primary cilium can drive cystogenesis.
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Selective autophagy of AKAP11 activates cAMP/PKA to fuel mitochondrial metabolism and tumor cell growth. Proc Natl Acad Sci U S A 2021; 118:2020215118. [PMID: 33785595 DOI: 10.1073/pnas.2020215118] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Autophagy is a catabolic pathway that provides self-nourishment and maintenance of cellular homeostasis. Autophagy is a fundamental cell protection pathway through metabolic recycling of various intracellular cargos and supplying the breakdown products. Here, we report an autophagy function in governing cell protection during cellular response to energy crisis through cell metabolic rewiring. We observe a role of selective type of autophagy in direct activation of cyclic AMP protein kinase A (PKA) and rejuvenation of mitochondrial function. Mechanistically, autophagy selectively degrades the inhibitory subunit RI of PKA holoenzyme through A-kinase-anchoring protein (AKAP) 11. AKAP11 acts as an autophagy receptor that recruits RI to autophagosomes via LC3. Glucose starvation induces AKAP11-dependent degradation of RI, resulting in PKA activation that potentiates PKA-cAMP response element-binding signaling, mitochondria respiration, and ATP production in accordance with mitochondrial elongation. AKAP11 deficiency inhibits PKA activation and impairs cell survival upon glucose starvation. Our results thus expand the view of autophagy cytoprotection mechanism by demonstrating selective autophagy in RI degradation and PKA activation that fuels the mitochondrial metabolism and confers cell resistance to glucose deprivation implicated in tumor growth.
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Regulation of Mitochondrial Homeostasis by sAC-Derived cAMP Pool: Basic and Translational Aspects. Cells 2021; 10:cells10020473. [PMID: 33671810 PMCID: PMC7926680 DOI: 10.3390/cells10020473] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/17/2021] [Accepted: 02/19/2021] [Indexed: 01/21/2023] Open
Abstract
In contrast to the traditional view of mitochondria being solely a source of cellular energy, e.g., the "powerhouse" of the cell, mitochondria are now known to be key regulators of numerous cellular processes. Accordingly, disturbance of mitochondrial homeostasis is a basic mechanism in several pathologies. Emerging data demonstrate that 3'-5'-cyclic adenosine monophosphate (cAMP) signalling plays a key role in mitochondrial biology and homeostasis. Mitochondria are equipped with an endogenous cAMP synthesis system involving soluble adenylyl cyclase (sAC), which localizes in the mitochondrial matrix and regulates mitochondrial function. Furthermore, sAC localized at the outer mitochondrial membrane contributes significantly to mitochondrial biology. Disturbance of the sAC-dependent cAMP pools within mitochondria leads to mitochondrial dysfunction and pathology. In this review, we discuss the available data concerning the role of sAC in regulating mitochondrial biology in relation to diseases.
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Adenylate control in cAMP signaling: implications for adaptation in signalosomes. Biochem J 2021; 477:2981-2998. [PMID: 32722762 DOI: 10.1042/bcj20200435] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/23/2020] [Accepted: 07/27/2020] [Indexed: 12/26/2022]
Abstract
In cAMP-Protein Kinase A (PKA) signaling, A-kinase anchoring protein scaffolds assemble PKA in close proximity to phosphodiesterases (PDE), kinase-substrates to form signaling islands or 'signalosomes'. In its basal state, inactive PKA holoenzyme (R2:C2) is activated by binding of cAMP to regulatory (R)-subunits leading to dissociation of active catalytic (C)-subunits. PDEs hydrolyze cAMP-bound to the R-subunits to generate 5'-AMP for termination and resetting the cAMP signaling. Mechanistic basis for cAMP signaling has been derived primarily by focusing on the proteins in isolation. Here, we set out to simulate cAMP signaling activation-termination cycles in a signalosome-like environment with PDEs and PKA subunits in close proximity to each other. Using a combination of fluorescence polarization and amide hydrogen exchange mass spectrometry with regulatory (RIα), C-subunit (Cα) and PDE8 catalytic domain, we have tracked movement of cAMP through activation-termination cycles. cAMP signaling operates as a continuum of four phases: (1) Activation and dissociation of PKA into R- and C-subunits by cAMP and facilitated by substrate (2) PDE recruitment to R-subunits (3) Hydrolysis of cAMP to 5'-AMP (4) Reassociation of C-subunit to 5'-AMP-bound-RIα in the presence of excess ATP to reset cAMP signaling to form the inactive PKA holoenzyme. Our results demonstrate that 5'-AMP is not merely a passive hydrolysis end-product of PDE action. A 'ligand-free' state R subunit does not exist in signalosomes as previously assumed. Instead the R-subunit toggles between cAMP- or 5'-AMP bound forms. This highlights, for the first time, the importance of 5'-AMP in promoting adaptation and uncovers adenylate control in cAMP signaling.
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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. SIGNIFICANCE STATEMENT: cAMP mediates the intracellular response to multiple hormones and neurotransmitters. Signal fidelity and accurate coordination of a plethora of different cellular functions is achieved via organization of multiprotein signalosomes and cAMP compartmentalization in subcellular nanodomains. Defining the organization and regulation of subcellular cAMP nanocompartments is necessary if we want to understand the complex functional ramifications of pharmacological treatments that target G protein-coupled receptors and for generating a blueprint that can be used to develop precision medicine 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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Changes in cAMP effector predominance are associated with increased oxytocin receptor expression in twin but not infection-associated or idiopathic preterm labour. PLoS One 2020; 15:e0240325. [PMID: 33253216 PMCID: PMC7703985 DOI: 10.1371/journal.pone.0240325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 09/24/2020] [Indexed: 11/19/2022] Open
Abstract
We previously reported that at term pregnancy, a decline in myometrial protein kinase A (PKA) activity leads to an exchange protein activated by cyclic AMP (Epac1)-dependent increase in oxytocin receptor (OTR) expression, promoting the onset of labour. Here, we studied the changes in the cyclic adenosine monophosphate (cAMP) effector system present in different phenotypes of preterm labour (PTL). Myometrial biopsies obtained from women with phenotypically distinct forms of PTL and the levels of PKA and OTR were examined. Although we found similar changes in the cAMP effector pathway in all forms of PTL, only in the case of twin PTL (T-PTL) was myometrial OTR levels increased in association with these results. Although there were several changes in the mRNA levels of components of the cAMP synthetic pathway, the total myometrial cAMP levels did not change with the onset of any subtype of PTL. With regards to the expression of cAMP-responsive genes, we found that the mRNA levels of 4 of the 5 cAMP-down-regulated genes were increased in T-PTL, similar to our findings in term labour. These data signify that although changes in the cAMP effector system were common to all forms of PTL, only in T-PTL were OTR levels increased. Similarly, the mRNA levels of cAMP-repressed genes were only increased in T-PTL supporting the concept that the decline in PKA levels influences myometrial function driving the onset of T-PTL.
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Di Benedetto G, Lefkimmiatis K, Pozzan T. The basics of mitochondrial cAMP signalling: Where, when, why. Cell Calcium 2020; 93:102320. [PMID: 33296837 DOI: 10.1016/j.ceca.2020.102320] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/16/2020] [Accepted: 11/16/2020] [Indexed: 12/15/2022]
Abstract
Cytosolic cAMP signalling in live cells has been extensively investigated in the past, while only in the last decade the existence of an intramitochondrial autonomous cAMP homeostatic system began to emerge. Thanks to the development of novel tools to investigate cAMP dynamics and cAMP/PKA-dependent phosphorylation within the matrix and in other mitochondrial compartments, it is now possible to address directly and in intact living cells a series of questions that until now could be addressed only by indirect approaches, in isolated organelles or through subcellular fractionation studies. In this contribution we discuss the mechanisms that regulate cAMP dynamics at the surface and inside mitochondria, and its crosstalk with organelle Ca2+ handling. We then address a series of still unsolved questions, such as the intramitochondrial localization of key elements of the cAMP signaling toolkit, e.g., adenylate cyclases, phosphodiesterases, protein kinase A (PKA) and Epac. Finally, we discuss the evidence for and against the existence of an intramitochondrial PKA pool and the functional role of cAMP increases within the organelle matrix.
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Affiliation(s)
- Giulietta Di Benedetto
- Neuroscience Institute, National Research Council of Italy (CNR), 35121 Padova, Italy; Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, 35129 Padova, Italy.
| | - Konstantinos Lefkimmiatis
- Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, 35129 Padova, Italy; Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy
| | - Tullio Pozzan
- Neuroscience Institute, National Research Council of Italy (CNR), 35121 Padova, Italy; Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, 35129 Padova, Italy; Department of Biomedical Sciences, University of Padova, 35121 Padova, Italy
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10
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Lobo MJ, Reverte-Salisa L, Chao YC, Koschinski A, Gesellchen F, Subramaniam G, Jiang H, Pace S, Larcom N, Paolocci E, Pfeifer A, Zanivan S, Zaccolo M. Phosphodiesterase 2A2 regulates mitochondria clearance through Parkin-dependent mitophagy. Commun Biol 2020; 3:596. [PMID: 33087821 PMCID: PMC7578833 DOI: 10.1038/s42003-020-01311-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 09/17/2020] [Indexed: 02/07/2023] Open
Abstract
Programmed degradation of mitochondria by mitophagy, an essential process to maintain mitochondrial homeostasis, is not completely understood. Here we uncover a regulatory process that controls mitophagy and involves the cAMP-degrading enzyme phosphodiesterase 2A2 (PDE2A2). We find that PDE2A2 is part of a mitochondrial signalosome at the mitochondrial inner membrane where it interacts with the mitochondrial contact site and organizing system (MICOS). As part of this compartmentalised signalling system PDE2A2 regulates PKA-mediated phosphorylation of the MICOS component MIC60, resulting in modulation of Parkin recruitment to the mitochondria and mitophagy. Inhibition of PDE2A2 is sufficient to regulate mitophagy in the absence of other triggers, highlighting the physiological relevance of PDE2A2 in this process. Pharmacological inhibition of PDE2 promotes a 'fat-burning' phenotype to retain thermogenic beige adipocytes, indicating that PDE2A2 may serve as a novel target with potential for developing therapies for metabolic disorders.
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Affiliation(s)
- Miguel J Lobo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | | | - Ying-Chi Chao
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Andreas Koschinski
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Frank Gesellchen
- Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, UK
| | | | - He Jiang
- Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, UK
| | - Samuel Pace
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Natasha Larcom
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Ester Paolocci
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Alexander Pfeifer
- Institute of Pharmacology and Toxicology University of Bonn, Bonn, Germany
| | - Sara Zanivan
- Cancer Research UK Beatson Institute, University of Glasgow, Glasgow, UK
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK
| | - Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
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Tian Y, Yang S, Gao S. Advances, Perspectives and Potential Engineering Strategies of Light-Gated Phosphodiesterases for Optogenetic Applications. Int J Mol Sci 2020; 21:E7544. [PMID: 33066112 PMCID: PMC7590022 DOI: 10.3390/ijms21207544] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/24/2020] [Accepted: 10/05/2020] [Indexed: 12/25/2022] Open
Abstract
The second messengers, cyclic adenosine 3'-5'-monophosphate (cAMP) and cyclic guanosine 3'-5'-monophosphate (cGMP), play important roles in many animal cells by regulating intracellular signaling pathways and modulating cell physiology. Environmental cues like temperature, light, and chemical compounds can stimulate cell surface receptors and trigger the generation of second messengers and the following regulations. The spread of cAMP and cGMP is further shaped by cyclic nucleotide phosphodiesterases (PDEs) for orchestration of intracellular microdomain signaling. However, localized intracellular cAMP and cGMP signaling requires further investigation. Optogenetic manipulation of cAMP and cGMP offers new opportunities for spatio-temporally precise study of their signaling mechanism. Light-gated nucleotide cyclases are well developed and applied for cAMP/cGMP manipulation. Recently discovered rhodopsin phosphodiesterase genes from protists established a new and direct biological connection between light and PDEs. Light-regulated PDEs are under development, and of demand to complete the toolkit for cAMP/cGMP manipulation. In this review, we summarize the state of the art, pros and cons of artificial and natural light-regulated PDEs, and discuss potential new strategies of developing light-gated PDEs for optogenetic manipulation.
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Affiliation(s)
| | | | - Shiqiang Gao
- Department of Neurophysiology, Physiological Institute, University of Wuerzburg, 97070 Wuerzburg, Germany; (Y.T.); (S.Y.)
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12
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A-Kinase Anchoring Protein 1: Emerging Roles in Regulating Mitochondrial Form and Function in Health and Disease. Cells 2020; 9:cells9020298. [PMID: 31991888 PMCID: PMC7072574 DOI: 10.3390/cells9020298] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/1970] [Revised: 01/17/2020] [Accepted: 01/21/2020] [Indexed: 01/01/2023] Open
Abstract
Best known as the powerhouse of the cell, mitochondria have many other important functions such as buffering intracellular calcium and reactive oxygen species levels, initiating apoptosis and supporting cell proliferation and survival. Mitochondria are also dynamic organelles that are constantly undergoing fission and fusion to meet specific functional needs. These processes and functions are regulated by intracellular signaling at the mitochondria. A-kinase anchoring protein 1 (AKAP1) is a scaffold protein that recruits protein kinase A (PKA), other signaling proteins, as well as RNA to the outer mitochondrial membrane. Hence, AKAP1 can be considered a mitochondrial signaling hub. In this review, we discuss what is currently known about AKAP1's function in health and diseases. We focus on the recent literature on AKAP1's roles in metabolic homeostasis, cancer and cardiovascular and neurodegenerative diseases. In healthy tissues, AKAP1 has been shown to be important for driving mitochondrial respiration during exercise and for mitochondrial DNA replication and quality control. Several recent in vivo studies using AKAP1 knockout mice have elucidated the role of AKAP1 in supporting cardiovascular, lung and neuronal cell survival in the stressful post-ischemic environment. In addition, we discuss the unique involvement of AKAP1 in cancer tumor growth, metastasis and resistance to chemotherapy. Collectively, the data indicate that AKAP1 promotes cell survival throug regulating mitochondrial form and function. Lastly, we discuss the potential of targeting of AKAP1 for therapy of various disorders.
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13
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Jakobsen E, Lange SC, Bak LK. Soluble adenylyl cyclase-mediated cAMP signaling and the putative role of PKA and EPAC in cerebral mitochondrial function. J Neurosci Res 2019; 97:1018-1038. [PMID: 31172581 DOI: 10.1002/jnr.24477] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 05/16/2019] [Accepted: 05/16/2019] [Indexed: 12/20/2022]
Abstract
Mitochondria produce the bulk of the ATP in most cells, including brain cells. Regulating this complex machinery to match the energetic needs of the cell is a complicated process that we have yet to understand in its entirety. In this context, 3',5'-cyclic AMP (cAMP) has been suggested to play a seminal role in signaling-metabolism coupling and regulation of mitochondrial ATP production. In cells, cAMP signals may affect mitochondria from the cytosolic side but more recently, a cAMP signal produced within the matrix of mitochondria by soluble adenylyl cyclase (sAC) has been suggested to regulate respiration and thus ATP production. However, little is known about these processes in brain mitochondria, and the effectors of the cAMP signal generated within the matrix are not completely clear since both protein kinase A (PKA) and exchange protein activated by cAMP 1 (EPAC1) have been suggested to be involved. Here, we review the current knowledge and relate it to brain mitochondria. Further, based on measurements of respiration, membrane potential, and ATP production in isolated mouse brain cortical mitochondria we show that inhibitors of sAC, PKA, or EPAC affect mitochondrial function in distinct ways. In conclusion, we suggest that brain mitochondria do regulate their function via sAC-mediated cAMP signals and that both PKA and EPAC could be involved downstream of sAC. Finally, due to the role of faulty mitochondrial function in a range of neurological diseases, we expect that the function of sAC-cAMP-PKA/EPAC signaling in brain mitochondria will likely attract further attention.
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Affiliation(s)
- Emil Jakobsen
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Sofie C Lange
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Lasse K Bak
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
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14
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cAMP/PKA signaling compartmentalization in cardiomyocytes: Lessons from FRET-based biosensors. J Mol Cell Cardiol 2019; 131:112-121. [PMID: 31028775 DOI: 10.1016/j.yjmcc.2019.04.020] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 04/19/2019] [Accepted: 04/19/2019] [Indexed: 12/29/2022]
Abstract
3',5'-cyclic adenosine monophosphate (cAMP) is a ubiquitous second messenger produced in response to the stimulation of G protein-coupled receptors (GPCRs). It regulates a plethora of pathophysiological processes in different organs, including the cardiovascular system. It is now clear that cAMP is not uniformly distributed within cardiac myocytes but confined in specific subcellular compartments where it modulates key players of the excitation-contraction coupling as well as other processes including gene transcription, mitochondrial homeostasis and cell death. This review will cover the major cAMP microdomains in cardiac myocytes. We will describe recent work using pioneering tools developed for investigating the organization and the function of the major cAMP microdomains in cardiomyocytes, including the plasma membrane, the sarcoplasmic reticulum, the myofilaments, the nucleus and the mitochondria.
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15
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Pozdniakova S, Ladilov Y. Functional Significance of the Adcy10-Dependent Intracellular cAMP Compartments. J Cardiovasc Dev Dis 2018; 5:E29. [PMID: 29751653 PMCID: PMC6023465 DOI: 10.3390/jcdd5020029] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/04/2018] [Accepted: 05/09/2018] [Indexed: 12/13/2022] Open
Abstract
Mounting evidence confirms the compartmentalized structure of evolutionarily conserved 3'⁻5'-cyclic adenosine monophosphate (cAMP) signaling, which allows for simultaneous participation in a wide variety of physiological functions and ensures specificity, selectivity and signal strength. One important player in cAMP signaling is soluble adenylyl cyclase (sAC). The intracellular localization of sAC allows for the formation of unique intracellular cAMP microdomains that control various physiological and pathological processes. This review is focused on the functional role of sAC-produced cAMP. In particular, we examine the role of sAC-cAMP in different cellular compartments, such as cytosol, nucleus and mitochondria.
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Affiliation(s)
- Sofya Pozdniakova
- Institute of Gender in Medicine, Center for Cardiovascular Research, Charite, 10115 Berlin, Germany.
- DZHK (German Center for Cardiovascular Research), Berlin Partner Site, 10115 Berlin, Germany.
| | - Yury Ladilov
- Institute of Gender in Medicine, Center for Cardiovascular Research, Charite, 10115 Berlin, Germany.
- DZHK (German Center for Cardiovascular Research), Berlin Partner Site, 10115 Berlin, Germany.
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16
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The role of compartmentalized signaling pathways in the control of mitochondrial activities in cancer cells. Biochim Biophys Acta Rev Cancer 2018; 1869:293-302. [PMID: 29673970 DOI: 10.1016/j.bbcan.2018.04.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 04/13/2018] [Accepted: 04/14/2018] [Indexed: 02/06/2023]
Abstract
Mitochondria are the powerhouse organelles present in all eukaryotic cells. They play a fundamental role in cell respiration, survival and metabolism. Stimulation of G-protein coupled receptors (GPCRs) by dedicated ligands and consequent activation of the cAMP·PKA pathway finely couple energy production and metabolism to cell growth and survival. Compartmentalization of PKA signaling at mitochondria by A-Kinase Anchor Proteins (AKAPs) ensures efficient transduction of signals generated at the cell membrane to the organelles, controlling important aspects of mitochondrial biology. Emerging evidence implicates mitochondria as essential bioenergetic elements of cancer cells that promote and support tumor growth and metastasis. In this context, mitochondria provide the building blocks for cellular organelles, cytoskeleton and membranes, and supply all the metabolic needs for the expansion and dissemination of actively replicating cancer cells. Functional interference with mitochondrial activity deeply impacts on cancer cell survival and proliferation. Therefore, mitochondria represent valuable targets of novel therapeutic approaches for the treatment of cancer patients. Understanding the biology of mitochondria, uncovering the molecular mechanisms regulating mitochondrial activity andmapping the relevant metabolic and signaling networks operating in cancer cells will undoubtly contribute to create a molecular platform to be used for the treatment of proliferative disorders. Here, we will highlight the emerging roles of signaling pathways acting downstream to GPCRs and their intersection with the ubiquitin proteasome system in the control of mitochondrial activity in different aspects of cancer cell biology.
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17
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Hernández-Ramírez LC, Trivellin G, Stratakis CA. Cyclic 3',5'-adenosine monophosphate (cAMP) signaling in the anterior pituitary gland in health and disease. Mol Cell Endocrinol 2018; 463:72-86. [PMID: 28822849 DOI: 10.1016/j.mce.2017.08.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 08/11/2017] [Accepted: 08/14/2017] [Indexed: 11/28/2022]
Abstract
The cyclic 3',5'-adenosine monophosphate (cAMP) was the first among the so-called "second messengers" to be described. It is conserved in most organisms and functions as a signal transducer by mediating the intracellular effects of multiple hormones and neurotransmitters. In this review, we first delineate how different members of the cAMP pathway ensure its correct compartmentalization and activity, mediate the terminal intracellular effects, and allow the crosstalk with other signaling pathways. We then focus on the pituitary gland, where cAMP exerts a crucial function by controlling the responsiveness of the cells to hypothalamic hormones, neurotransmitters and peripheral factors. We discuss the most relevant physiological functions mediated by cAMP in the different pituitary cell types, and summarize the defects affecting this pathway that have been reported in the literature. We finally discuss how a deregulated cAMP pathway is involved in the pathogenesis of pituitary disorders and how it affects the response to therapy.
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Affiliation(s)
- Laura C Hernández-Ramírez
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), 10 Center Drive, CRC, Room 1E-3216, Bethesda, MD 20892-1862, USA
| | - Giampaolo Trivellin
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), 10 Center Drive, CRC, Room 1E-3216, Bethesda, MD 20892-1862, USA
| | - Constantine A Stratakis
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), 10 Center Drive, CRC, Room 1E-3216, Bethesda, MD 20892-1862, USA.
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18
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Leroy J, Vandecasteele G, Fischmeister R. Cyclic AMP signaling in cardiac myocytes. CURRENT OPINION IN PHYSIOLOGY 2018. [DOI: 10.1016/j.cophys.2017.11.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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19
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O'Banion CP, Priestman MA, Hughes RM, Herring LE, Capuzzi SJ, Lawrence DS. Design and Profiling of a Subcellular Targeted Optogenetic cAMP-Dependent Protein Kinase. Cell Chem Biol 2018; 25:100-109.e8. [PMID: 29104065 PMCID: PMC5777159 DOI: 10.1016/j.chembiol.2017.09.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 08/21/2017] [Accepted: 09/27/2017] [Indexed: 11/30/2022]
Abstract
Although the cAMP-dependent protein kinase (PKA) is ubiquitously expressed, it is sequestered at specific subcellular locations throughout the cell, thereby resulting in compartmentalized cellular signaling that triggers site-specific behavioral phenotypes. We developed a three-step engineering strategy to construct an optogenetic PKA (optoPKA) and demonstrated that, upon illumination, optoPKA migrates to specified intracellular sites. Furthermore, we designed intracellular spatially segregated reporters of PKA activity and confirmed that optoPKA phosphorylates these reporters in a light-dependent fashion. Finally, proteomics experiments reveal that light activation of optoPKA results in the phosphorylation of known endogenous PKA substrates as well as potential novel substrates.
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Affiliation(s)
- Colin P O'Banion
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Melanie A Priestman
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Robert M Hughes
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Chemistry; East Carolina University, Greenville, NC 27858, USA
| | - Laura E Herring
- UNC Proteomics Core, Department of Pharmacology, UNC School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Stephen J Capuzzi
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599, USA
| | - David S Lawrence
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599, USA.
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20
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Valsecchi F, Konrad C, D'Aurelio M, Ramos-Espiritu LS, Stepanova A, Burstein SR, Galkin A, Magranè J, Starkov A, Buck J, Levin LR, Manfredi G. Distinct intracellular sAC-cAMP domains regulate ER Ca 2+ signaling and OXPHOS function. J Cell Sci 2017; 130:3713-3727. [PMID: 28864766 DOI: 10.1242/jcs.206318] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 08/29/2017] [Indexed: 12/20/2022] Open
Abstract
cAMP regulates a wide variety of physiological functions in mammals. This single second messenger can regulate multiple, seemingly disparate functions within independently regulated cell compartments. We have previously identified one such compartment inside the matrix of the mitochondria, where soluble adenylyl cyclase (sAC) regulates oxidative phosphorylation (OXPHOS). We now show that sAC knockout fibroblasts have a defect in OXPHOS activity and attempt to compensate for this defect by increasing OXPHOS proteins. Importantly, sAC knockout cells also exhibit decreased probability of endoplasmic reticulum (ER) Ca2+ release associated with diminished phosphorylation of the inositol 3-phosphate receptor. Restoring sAC expression exclusively in the mitochondrial matrix rescues OXPHOS activity and reduces mitochondrial biogenesis, indicating that these phenotypes are regulated by intramitochondrial sAC. In contrast, Ca2+ release from the ER is only rescued when sAC expression is restored throughout the cell. Thus, we show that functionally distinct, sAC-defined, intracellular cAMP signaling domains regulate metabolism and Ca2+ signaling.
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Affiliation(s)
| | - Csaba Konrad
- Brain and Mind Research Institute, New York, NY 10065, USA
| | | | - Lavoisier S Ramos-Espiritu
- Department of Pharmacology, Weill Cornell Medicine, New York, NY 10065, USA.,High-Throughput and Spectroscopy Resource Center, The Rockefeller University, New York, NY 10065, USA
| | - Anna Stepanova
- Brain and Mind Research Institute, New York, NY 10065, USA
| | | | | | - Jordi Magranè
- Brain and Mind Research Institute, New York, NY 10065, USA
| | | | - Jochen Buck
- Department of Pharmacology, Weill Cornell Medicine, New York, NY 10065, USA
| | - Lonny R Levin
- Department of Pharmacology, Weill Cornell Medicine, New York, NY 10065, USA
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