The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Jochen Buck - One of the best experts on this subject based on the ideXlab platform.
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external fertilization is orchestrated by a ph regulated Soluble Adenylyl Cyclase controlling sperm motility and chemotaxis
bioRxiv, 2021Co-Authors: H G Koerschen, Jochen Buck, Lonny R Levin, N Kaur, Hussein Hamzeh, Rene Pascal, Luis Alvarez, W Boenigk, C KambachAbstract:The reaction of CO2 with H2O to form HCO3- and H+ is one of the most important chemical equilibria in cells. In mammalian sperm, a Soluble Adenylyl Cyclase (sAC) serves as cellular HCO3- sensor that conveys the equilibrium state via cAMP synthesis to cAMP-signaling molecules. The function of sAC and cAMP in non-mammalian sperm is largely unknown. Here, we identify sAC orthologs in sea urchin and salmon sperm that, surprisingly, are activated by alkaline pH rather than HCO3-. Two amino-acid residues required for HCO3- binding of mammalian sAC are lacking in pH-regulated sAC. Orthologs identified in ten other phyla are also lacking either one of these key residues, suggesting that pH control is widespread among non-mammalian metazoan. The pH-sensitive sAC controls several functions of sperm from external fertilizers. Upon spawning, alkalization triggers cAMP synthesis and, thereby, activates motility of quiescent sperm. Egg-derived chemoattractants also alkalize sperm and elevate cAMP, which then-modulates pacemaker HCN channels to trigger a chemotactic Ca2+ response. Finally, the sAC and the voltage- and cAMP-activated Na+/H+ exchanger sNHE mutually control each other. A picture of evolutionary significance is emerging: motility and sensory signaling of sperm from both internal and external fertilizers rely on cAMP, yet, their sAC is regulated by HCO3- or pHi, respectively. Acidification of aquatic habitats due to climate change may adversely affect pH-sensing by sAC and thereby sexual reproduction in the sea.
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bicarbonate carbon dioxide and ph sensing via mammalian bicarbonate regulated Soluble Adenylyl Cyclase
Interface Focus, 2021Co-Authors: Tom Rossetti, Jochen Buck, Stephanie Jackvony, Lonny R LevinAbstract:Soluble Adenylyl Cyclase (sAC; ADCY10) is a bicarbonate (HCO3−)-regulated enzyme responsible for the generation of cyclic adenosine monophosphate (cAMP). sAC is distributed throughout the cell and ...
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Soluble Adenylyl Cyclase regulates the cytosolic nadh nad redox state and the bioenergetic switch between glycolysis and oxidative phosphorylation
Biochimica et Biophysica Acta, 2021Co-Authors: Jungchin Chang, E H Gilglioni, Jochen Buck, Lonny R Levin, Suzanne Duijst, Daan M Panneman, Richard J Rodenburg, Hsuli Huang, Arthur J VerhoevenAbstract:Abstract The evolutionarily conserved Soluble Adenylyl Cyclase (sAC, ADCY10) mediates cAMP signaling exclusively in intracellular compartments. Because sAC activity is sensitive to local concentrations of ATP, bicarbonate, and free Ca2+, sAC is potentially an important metabolic sensor. Nonetheless, little is known about how sAC regulates energy metabolism in intact cells. In this study, we demonstrated that both pharmacological and genetic suppression of sAC resulted in increased lactate secretion and decreased pyruvate secretion in multiple cell lines and primary cultures of mouse hepatocytes and cholangiocytes. The increased extracellular lactate-to-pyruvate ratio upon sAC suppression reflected an increased cytosolic free [NADH]/[NAD+] ratio, which was corroborated by using the NADH/NAD+ redox biosensor Peredox-mCherry. Mechanistic studies in permeabilized HepG2 cells showed that sAC inhibition specifically suppressed complex I of the mitochondrial respiratory chain. A survey of cAMP effectors revealed that only selective inhibition of exchange protein activated by cAMP 1 (Epac1), but not protein kinase A (PKA) or Epac2, suppressed complex I-dependent respiration and significantly increased the cytosolic NADH/NAD+ redox state. Analysis of the ATP production rate and the adenylate energy charge showed that inhibiting sAC reciprocally affects ATP production by glycolysis and oxidative phosphorylation while maintaining cellular energy homeostasis. In conclusion, our study shows that, via the regulation of complex I-dependent mitochondrial respiration, sAC-Epac1 signaling regulates the cytosolic NADH/NAD+ redox state, and coordinates oxidative phosphorylation and glycolysis to maintain cellular energy homeostasis. As such, sAC is effectively a bioenergetic switch between aerobic glycolysis and oxidative phosphorylation at the post-translational level.
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pharmacological modulation of the co2 hco3 ph calcium and atp sensing Soluble Adenylyl Cyclase
Pharmacology & Therapeutics, 2018Co-Authors: Shakarr V Wiggins, Lonny R Levin, Clemens Steegborn, Jochen BuckAbstract:Cyclic AMP (cAMP), the prototypical second messenger, has been implicated in a wide variety of (often opposing) physiological processes. It simultaneously mediates multiple, diverse processes, often within a single cell, by acting locally within independently-regulated and spatially-restricted microdomains. Within each microdomain, the level of cAMP will be dependent upon the balance between its synthesis by Adenylyl Cyclases and its degradation by phosphodiesterases (PDEs). In mammalian cells, there are many PDE isoforms and two types of Adenylyl Cyclases; the G protein regulated transmembrane Adenylyl Cyclases (tmACs) and the CO2/HCO3-/pH-, calcium-, and ATP-sensing Soluble Adenylyl Cyclase (sAC). Discriminating the roles of individual cyclic nucleotide microdomains requires pharmacological modulators selective for the various PDEs and/or Adenylyl Cyclases. Such tools present an opportunity to develop therapeutics specifically targeted to individual cAMP dependent pathways. The pharmacological modulators of tmACs have recently been reviewed, and in this review, we describe the current status of pharmacological tools available for studying sAC.
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differential intraocular pressure measurements by tonometry and direct cannulation after treatment with Soluble Adenylyl Cyclase inhibitors
Journal of Ocular Pharmacology and Therapeutics, 2017Co-Authors: Jarel K Gandhi, Jochen Buck, Lonny R Levin, Uttio Roy Chowdhury, Zahid Manzar, Michael P Fautsch, Alan D MarmorsteinAbstract:Abstract Purpose: To validate the increase in intraocular pressure (IOP) caused by Soluble Adenylyl Cyclase (sAC) inhibitors and determine reasons behind variation in IOP measurements performed by tonometry. Methods: C57BL/6J mice were administered DMSO solubilized sAC inhibitors (KH7 or LRE-1) by intraperitoneal injection. Two hours post-treatment, mice were anesthetized with avertin or ketamine/xylazine/acepromazine (KXA). IOP was measured by a rebound tonometer or direct cannulation of the anterior chamber. Spectral-domain optical coherence tomography was used to measure anterior chamber depth and corneal thickness in live mice. Outflow facility was measured in perfused, enucleated mouse eyes. Results: Compared with DMSO controls, KH7 treatment caused an increased IOP in avertin- and KXA-anesthetized mice when measured by direct cannulation [avertin: 14.4 ± 2.1 mmHg vs. 11.1 ± 1.0 mmHg (P = 0.003); KXA: 14.4 ± 1.0 mmHg vs. 11.3 ± 0.8 mmHg (P < 0.001)] and tonometry [avertin: 10.8 ± 1.4 mmHg vs. 7.4 ± 0...
Lonny R Levin - One of the best experts on this subject based on the ideXlab platform.
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external fertilization is orchestrated by a ph regulated Soluble Adenylyl Cyclase controlling sperm motility and chemotaxis
bioRxiv, 2021Co-Authors: H G Koerschen, Jochen Buck, Lonny R Levin, N Kaur, Hussein Hamzeh, Rene Pascal, Luis Alvarez, W Boenigk, C KambachAbstract:The reaction of CO2 with H2O to form HCO3- and H+ is one of the most important chemical equilibria in cells. In mammalian sperm, a Soluble Adenylyl Cyclase (sAC) serves as cellular HCO3- sensor that conveys the equilibrium state via cAMP synthesis to cAMP-signaling molecules. The function of sAC and cAMP in non-mammalian sperm is largely unknown. Here, we identify sAC orthologs in sea urchin and salmon sperm that, surprisingly, are activated by alkaline pH rather than HCO3-. Two amino-acid residues required for HCO3- binding of mammalian sAC are lacking in pH-regulated sAC. Orthologs identified in ten other phyla are also lacking either one of these key residues, suggesting that pH control is widespread among non-mammalian metazoan. The pH-sensitive sAC controls several functions of sperm from external fertilizers. Upon spawning, alkalization triggers cAMP synthesis and, thereby, activates motility of quiescent sperm. Egg-derived chemoattractants also alkalize sperm and elevate cAMP, which then-modulates pacemaker HCN channels to trigger a chemotactic Ca2+ response. Finally, the sAC and the voltage- and cAMP-activated Na+/H+ exchanger sNHE mutually control each other. A picture of evolutionary significance is emerging: motility and sensory signaling of sperm from both internal and external fertilizers rely on cAMP, yet, their sAC is regulated by HCO3- or pHi, respectively. Acidification of aquatic habitats due to climate change may adversely affect pH-sensing by sAC and thereby sexual reproduction in the sea.
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bicarbonate carbon dioxide and ph sensing via mammalian bicarbonate regulated Soluble Adenylyl Cyclase
Interface Focus, 2021Co-Authors: Tom Rossetti, Jochen Buck, Stephanie Jackvony, Lonny R LevinAbstract:Soluble Adenylyl Cyclase (sAC; ADCY10) is a bicarbonate (HCO3−)-regulated enzyme responsible for the generation of cyclic adenosine monophosphate (cAMP). sAC is distributed throughout the cell and ...
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Soluble Adenylyl Cyclase regulates the cytosolic nadh nad redox state and the bioenergetic switch between glycolysis and oxidative phosphorylation
Biochimica et Biophysica Acta, 2021Co-Authors: Jungchin Chang, E H Gilglioni, Jochen Buck, Lonny R Levin, Suzanne Duijst, Daan M Panneman, Richard J Rodenburg, Hsuli Huang, Arthur J VerhoevenAbstract:Abstract The evolutionarily conserved Soluble Adenylyl Cyclase (sAC, ADCY10) mediates cAMP signaling exclusively in intracellular compartments. Because sAC activity is sensitive to local concentrations of ATP, bicarbonate, and free Ca2+, sAC is potentially an important metabolic sensor. Nonetheless, little is known about how sAC regulates energy metabolism in intact cells. In this study, we demonstrated that both pharmacological and genetic suppression of sAC resulted in increased lactate secretion and decreased pyruvate secretion in multiple cell lines and primary cultures of mouse hepatocytes and cholangiocytes. The increased extracellular lactate-to-pyruvate ratio upon sAC suppression reflected an increased cytosolic free [NADH]/[NAD+] ratio, which was corroborated by using the NADH/NAD+ redox biosensor Peredox-mCherry. Mechanistic studies in permeabilized HepG2 cells showed that sAC inhibition specifically suppressed complex I of the mitochondrial respiratory chain. A survey of cAMP effectors revealed that only selective inhibition of exchange protein activated by cAMP 1 (Epac1), but not protein kinase A (PKA) or Epac2, suppressed complex I-dependent respiration and significantly increased the cytosolic NADH/NAD+ redox state. Analysis of the ATP production rate and the adenylate energy charge showed that inhibiting sAC reciprocally affects ATP production by glycolysis and oxidative phosphorylation while maintaining cellular energy homeostasis. In conclusion, our study shows that, via the regulation of complex I-dependent mitochondrial respiration, sAC-Epac1 signaling regulates the cytosolic NADH/NAD+ redox state, and coordinates oxidative phosphorylation and glycolysis to maintain cellular energy homeostasis. As such, sAC is effectively a bioenergetic switch between aerobic glycolysis and oxidative phosphorylation at the post-translational level.
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pharmacological modulation of the co2 hco3 ph calcium and atp sensing Soluble Adenylyl Cyclase
Pharmacology & Therapeutics, 2018Co-Authors: Shakarr V Wiggins, Lonny R Levin, Clemens Steegborn, Jochen BuckAbstract:Cyclic AMP (cAMP), the prototypical second messenger, has been implicated in a wide variety of (often opposing) physiological processes. It simultaneously mediates multiple, diverse processes, often within a single cell, by acting locally within independently-regulated and spatially-restricted microdomains. Within each microdomain, the level of cAMP will be dependent upon the balance between its synthesis by Adenylyl Cyclases and its degradation by phosphodiesterases (PDEs). In mammalian cells, there are many PDE isoforms and two types of Adenylyl Cyclases; the G protein regulated transmembrane Adenylyl Cyclases (tmACs) and the CO2/HCO3-/pH-, calcium-, and ATP-sensing Soluble Adenylyl Cyclase (sAC). Discriminating the roles of individual cyclic nucleotide microdomains requires pharmacological modulators selective for the various PDEs and/or Adenylyl Cyclases. Such tools present an opportunity to develop therapeutics specifically targeted to individual cAMP dependent pathways. The pharmacological modulators of tmACs have recently been reviewed, and in this review, we describe the current status of pharmacological tools available for studying sAC.
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differential intraocular pressure measurements by tonometry and direct cannulation after treatment with Soluble Adenylyl Cyclase inhibitors
Journal of Ocular Pharmacology and Therapeutics, 2017Co-Authors: Jarel K Gandhi, Jochen Buck, Lonny R Levin, Uttio Roy Chowdhury, Zahid Manzar, Michael P Fautsch, Alan D MarmorsteinAbstract:Abstract Purpose: To validate the increase in intraocular pressure (IOP) caused by Soluble Adenylyl Cyclase (sAC) inhibitors and determine reasons behind variation in IOP measurements performed by tonometry. Methods: C57BL/6J mice were administered DMSO solubilized sAC inhibitors (KH7 or LRE-1) by intraperitoneal injection. Two hours post-treatment, mice were anesthetized with avertin or ketamine/xylazine/acepromazine (KXA). IOP was measured by a rebound tonometer or direct cannulation of the anterior chamber. Spectral-domain optical coherence tomography was used to measure anterior chamber depth and corneal thickness in live mice. Outflow facility was measured in perfused, enucleated mouse eyes. Results: Compared with DMSO controls, KH7 treatment caused an increased IOP in avertin- and KXA-anesthetized mice when measured by direct cannulation [avertin: 14.4 ± 2.1 mmHg vs. 11.1 ± 1.0 mmHg (P = 0.003); KXA: 14.4 ± 1.0 mmHg vs. 11.3 ± 0.8 mmHg (P < 0.001)] and tonometry [avertin: 10.8 ± 1.4 mmHg vs. 7.4 ± 0...
Martin Tresguerres - One of the best experts on this subject based on the ideXlab platform.
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regulation of coral calcification by the acid base sensing enzyme Soluble Adenylyl Cyclase
Biochemical and Biophysical Research Communications, 2020Co-Authors: Katie L Barott, Alexander A Venn, Angus B Thies, Sylvie Tambutte, Martin TresguerresAbstract:Coral calcification is intricately linked to the chemical composition of the fluid in the extracellular calcifying medium (ECM), which is situated between the calcifying cells and the skeleton. Here we demonstrate that the acid-base sensing enzyme Soluble Adenylyl Cyclase (sAC) is expressed in calcifying cells of the coral Stylophora pistillata. Furthermore, pharmacological inhibition of sAC in coral microcolonies resulted in acidification of the ECM as estimated by the pH-sensitive ratiometric indicator SNARF, and decreased calcification rates, as estimated by calcein labeling of crystal growth. These results indicate that sAC activity modulates some of the molecular machinery involved in producing the coral skeleton, which could include ion-transporting proteins and vesicular transport. To our knowledge this is the first study to directly demonstrate biological regulation of the alkaline pH of the coral ECM and its correlation with calcification.
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molecular enzymatic and cellular characterization of Soluble Adenylyl Cyclase from aquatic animals
Methods in Enzymology, 2018Co-Authors: Martin Tresguerres, Cristina SalmeronAbstract:The enzyme Soluble Adenylyl Cyclase (sAC) is the most recently identified source of the messenger molecule cyclic adenosine monophosphate. sAC is evolutionarily conserved from cyanobacteria to human, is directly stimulated by [Formula: see text] ions, and can act as a sensor of environmental and metabolic CO2, pH, and [Formula: see text] levels. sAC genes tend to have multiple alternative promoters, undergo extensive alternative splicing, be translated into low mRNA levels, and the numerous sAC protein isoforms may be present in various subcellular localizations. In aquatic organisms, sAC has been shown to mediate various functions including intracellular pH regulation in coral, blood acid/base regulation in shark, heart beat rate in hagfish, and NaCl absorption in fish intestine. Furthermore, sAC is present in multiple other species and tissues, and sAC protein and enzymatic activity have been reported in the cytoplasm, the nucleus, and other subcellular compartments, suggesting even more diverse physiological roles. Although the methods and experimental tools used to study sAC are conventional, the complexity of sAC genes and proteins requires special considerations that are discussed in this chapter.
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established and potential physiological roles of bicarbonate sensing Soluble Adenylyl Cyclase sac in aquatic animals
The Journal of Experimental Biology, 2014Co-Authors: Martin Tresguerres, Katie L Barott, Megan E Barron, Jinae N RoaAbstract:Soluble Adenylyl Cyclase (sAC) is a recently recognized source of the signaling molecule cyclic AMP (cAMP) that is genetically and biochemically distinct from the classic G-protein-regulated transmembrane Adenylyl Cyclases (tmACs). Mammalian sAC is distributed throughout the cytoplasm and it may be present in the nucleus and inside mitochondria. sAC activity is directly stimulated by HCO3−, and sAC has been confirmed to be a HCO3− sensor in a variety of mammalian cell types. In addition, sAC can functionally associate with carbonic anhydrases to act as a de facto sensor of pH and CO2. The two catalytic domains of sAC are related to HCO3−-regulated Adenylyl Cyclases from cyanobacteria, suggesting the cAMP pathway is an evolutionarily conserved mechanism for sensing CO2 levels and/or acid/base conditions. Reports of sAC in aquatic animals are still limited but are rapidly accumulating. In shark gills, sAC senses blood alkalosis and triggers compensatory H+ absorption. In the intestine of bony fishes, sAC modulates NaCl and water absorption. And in sea urchin sperm, sAC may participate in the initiation of flagellar movement and in the acrosome reaction. Bioinformatics and RT-PCR results reveal that sAC orthologs are present in most animal phyla. This review summarizes the current knowledge on the physiological roles of sAC in aquatic animals and suggests additional functions in which sAC may be involved.
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regulation of anterior chamber drainage by bicarbonate sensitive Soluble Adenylyl Cyclase in the ciliary body
Journal of Biological Chemistry, 2011Co-Authors: Kenneth C Hess, Jochen Buck, Lonny R Levin, Martin Tresguerres, Lihua Y Marmorstein, Alan D MarmorsteinAbstract:Abstract Glaucoma is a leading cause of blindness affecting as many as 2.2 million Americans. All current glaucoma treatment strategies aim to reduce intraocular pressure (IOP). IOP results from the resistance to drainage of aqueous humor (AH) produced by the ciliary body in a process requiring bicarbonate. Once secreted into the anterior chamber, AH drains from the eye via two pathways: uveoscleral and pressure-dependent or conventional outflow (Ct). Modulation of “inflow” and “outflow” pathways is thought to occur via distinct, local mechanisms. Mice deficient in the bicarbonate channel bestrophin-2 (Best2), however, exhibit a lower IOP despite an increase in AH production. Best2 is expressed uniquely in nonpigmented ciliary epithelial (NPE) cells providing evidence for a bicarbonate-dependent communicative pathway linking inflow and outflow. Here, we show that bicarbonate-sensitive Soluble Adenylyl Cyclase (sAC) is highly expressed in the ciliary body in NPE cells, but appears to be absent from drainage tissues. Pharmacologic inhibition of sAC in mice causes a significant increase in IOP due to a decrease in Ct with no effect on inflow. In mice deficient in sAC IOP is elevated, and Ct is decreased relative to wild-type mice. Pharmacologic inhibition of sAC did not alter IOP or Ct in sAC-deficient mice. Based on these data we propose that the ciliary body can regulate Ct and that sAC serves as a critical sensor of bicarbonate in the ciliary body regulating the secretion of substances into the AH that govern outflow facility independent of pressure.
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intracellular camp signaling by Soluble Adenylyl Cyclase
Kidney International, 2011Co-Authors: Martin Tresguerres, Lonny R Levin, Jochen BuckAbstract:Soluble Adenylyl Cyclase (sAC) is a recently identified source of the ubiquitous second messenger cyclic adenosine 3′,5′ monophosphate (cAMP). sAC is distinct from the more widely studied source of cAMP, the transmembrane Adenylyl Cyclases (tmACs); its activity is uniquely regulated by bicarbonate anions, and it is distributed throughout the cytoplasm and in cellular organelles. Due to its unique localization and regulation, sAC has various functions in a variety of physiological systems that are distinct from tmACs. In this review, we detail the known functions of sAC, and we reassess commonly held views of cAMP signaling inside cells.
Jonathan H. Zippin - One of the best experts on this subject based on the ideXlab platform.
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35336 effect of nuclear Soluble Adenylyl Cyclase sac on melanoma treatment response
Journal of Clinical and Translational Science, 2021Co-Authors: Jakyung Bang, Marek M Drozdz, Lauren Dong, Taha Merghoub, Jonathan H. ZippinAbstract:ABSTRACT IMPACT: Our data identify a novel candidate for combination strategy in melanoma treatment, and can inform clinicians in their decision-making process regarding therapeutic intervention for melanoma patients. OBJECTIVES/GOALS: Soluble Adenylyl Cyclase (sAC) is a novel source of cyclic AMP (cAMP). In melanoma, nuclear sAC localization has an established diagnostic utility and we newly found that nuclear sAC functions as a tumor suppressor by inhibiting Hippo pathway, which affects treatment response. Here, we examine the effect of nuclear sAC on melanoma treatment response. METHODS/STUDY POPULATION: We developed a doxycycline inducible system for increasing sAC activity only in the nucleus. We assessed whether nuclear sAC activity affects treatment response, using BRAFV600 human melanoma cell lines. Using a clonogenic assay, we examined how nuclear sAC activity affects growth inhibition in the presence of a BRAF inhibitor, vemurafenib. Our findings will be confirmed in vivo using tumor xenografts. After tumor formation in NSG mice, mice will be randomized to be fed normal or doxycycline chow for nuclear sAC induction, then subdivided to receive vehicle or vemurafenib to examine the effect of nuclear sAC activity on treatment response in vivo. We will also compare melanoma biopsies collected before and after treatment with BRAF inhibitors to assess how nuclear sAC staining affects tumor morphology in vivo. RESULTS/ANTICIPATED RESULTS: So far, nuclear sAC activity has rendered SkMel178 and M263 cell lines more susceptible to vemurafenib. Cell viability was inversely correlated both with vemurafenib and with doxycycline concentration. Cell viability after vemurafenib treatment was dramatically reduced when nuclear sAC was activated. It appears that nuclear sAC enhances the sensitivity of BRAF mutant melanomas to vemurafenib in vitro. We anticipate that xenografts of these cells in mice will be more susceptible to vemurafenib when nuclear sAC is activated. We also anticipate that positive nuclear sAC staining will correlate with a favorable response to therapy. DISCUSSION/SIGNIFICANCE OF FINDINGS: Targeted therapy with BRAF inhibitors is used in late-stage melanomas, but its use is limited as patients invariably acquire resistance. Here, we identified nuclear sAC activation as a novel candidate for combination strategy. Our data will also inform clinicians how best to integrate this biomarker into their decision-making regarding therapy.
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investigation of camp microdomains as a path to novel cancer diagnostics
Biochimica et Biophysica Acta, 2014Co-Authors: Garrett Desman, Caren Waintraub, Jonathan H. ZippinAbstract:Understanding of cAMP signaling has greatly improved over the past decade. The advent of live cell imaging techniques and more specific pharmacologic modulators has led to an improved understanding of the intricacies by which cAMP is able to modulate such a wide variety of cellular pathways. It is now appreciated that cAMP is able to activate multiple effector proteins at distinct areas in the cell leading to the activation of very different downstream targets. The investigation of signaling proteins in cancer is a common route to the development of diagnostic tools, prognostic tools, and/or therapeutic targets, and in this review we highlight how investigation of cAMP signaling microdomains driven by the Soluble Adenylyl Cyclase in different cancers has led to the development of a novel cancer biomarker. Antibodies directed against the Soluble Adenylyl Cyclase (sAC) are highly specific markers for melanoma especially for lentigo maligna melanoma and are being described as “second generation” cancer diagnostics, which are diagnostics that determine the ‘state’ of a cell and not just identify the cell type. Due to the wide presence of cAMP signaling pathways in cancer, we predict that further investigation of both sAC and other cAMP microdomains will lead to additional cancer biomarkers. This article is part of a Special Issue entitled: The role of Soluble Adenylyl Cyclase in health and disease.
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co2 hco3 and calcium regulated Soluble Adenylyl Cyclase as a physiological atp sensor
Journal of Biological Chemistry, 2013Co-Authors: Jonathan H. Zippin, Kenneth C Hess, Yanqiu Chen, George G Holz, Susanne G Straub, Ana Garcia Diaz, Dana Lee, Patrick Tso, Geoffrey W G Sharp, Lonny R LevinAbstract:The second messenger molecule cAMP is integral for many physiological processes. In mammalian cells, cAMP can be generated from hormone- and G protein-regulated transmembrane Adenylyl Cyclases or via the widely expressed and structurally and biochemically distinct enzyme Soluble Adenylyl Cyclase (sAC). sAC activity is uniquely stimulated by bicarbonate ions, and in cells, sAC functions as a physiological carbon dioxide, bicarbonate, and pH sensor. sAC activity is also stimulated by calcium, and its affinity for its substrate ATP suggests that it may be sensitive to physiologically relevant fluctuations in intracellular ATP. We demonstrate here that sAC can function as a cellular ATP sensor. In cells, sAC-generated cAMP reflects alterations in intracellular ATP that do not affect transmembrane AC-generated cAMP. In β cells of the pancreas, glucose metabolism generates ATP, which corresponds to an increase in cAMP, and we show here that sAC is responsible for an ATP-dependent cAMP increase. Glucose metabolism also elicits insulin secretion, and we further show that sAC is necessary for normal glucose-stimulated insulin secretion in vitro and in vivo.
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type 10 Soluble Adenylyl Cyclase is overexpressed in prostate carcinoma and controls proliferation of prostate cancer cells
Journal of Biological Chemistry, 2013Co-Authors: Janpaul Flacke, Jonathan H. Zippin, Avinash Appukuttan, Hanna Flacke, Peter H Reusch, Reinjuri Palisaar, Joachim Noldus, Brian D Robinson, Yury LadilovAbstract:cAMP signaling plays an essential role in modulating the proliferation of different cell types, including cancer cells. Until now, the regulation of this pathway was restricted to the transmembrane class of Adenylyl Cyclases. In this study, significant overexpression of Soluble Adenylyl Cyclase (sAC), an alternative source of cAMP, was found in human prostate carcinoma, and therefore, the contribution of this Cyclase was investigated in the prostate carcinoma cell lines LNCaP and PC3. Suppression of sAC activity by treatment with the sAC-specific inhibitor KH7 or by sAC-specific knockdown mediated by siRNA or shRNA transfection prevented the proliferation of prostate carcinoma cells, led to lactate dehydrogenase release, and induced apoptosis. Cell cycle analysis revealed a significant rise in the G2 phase population 12 h after sAC inhibition, which was accompanied by the down-regulation of cyclin B1 and CDK1. sAC-dependent regulation of proliferation involves the EPAC/Rap1/B-Raf signaling pathway. In contrast, protein kinase A does not play a role. In conclusion, this study suggests a novel sAC-dependent signaling pathway that controls the proliferation of prostate carcinoma cells. Background: Soluble Adenylyl Cyclase (sAC) may be an alternative intracellular localized source of cAMP controlling proliferation. Results: sAC is overexpressed in prostate carcinoma, and inhibition of sAC leads to cell cycle arrest. Conclusion: sAC controls proliferation of prostate carcinoma cells. Significance: sAC represents a novel pathway promoting proliferation in cancer cells and is a promising target for prostate cancer treatment.
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type 10 Soluble Adenylyl Cyclase is overexpressed in prostate carcinoma and controls proliferation of prostate cancer cells
Journal of Biological Chemistry, 2013Co-Authors: Janpaul Flacke, Jonathan H. Zippin, Avinash Appukuttan, Hanna Flacke, Peter H Reusch, Reinjuri Palisaar, Joachim Noldus, Brian D Robinson, Yury LadilovAbstract:cAMP signaling plays an essential role in modulating the proliferation of different cell types, including cancer cells. Until now, the regulation of this pathway was restricted to the transmembrane class of Adenylyl Cyclases. In this study, significant overexpression of Soluble Adenylyl Cyclase (sAC), an alternative source of cAMP, was found in human prostate carcinoma, and therefore, the contribution of this Cyclase was investigated in the prostate carcinoma cell lines LNCaP and PC3. Suppression of sAC activity by treatment with the sAC-specific inhibitor KH7 or by sAC-specific knockdown mediated by siRNA or shRNA transfection prevented the proliferation of prostate carcinoma cells, led to lactate dehydrogenase release, and induced apoptosis. Cell cycle analysis revealed a significant rise in the G(2) phase population 12 h after sAC inhibition, which was accompanied by the down-regulation of cyclin B(1) and CDK1. sAC-dependent regulation of proliferation involves the EPAC/Rap1/B-Raf signaling pathway. In contrast, protein kinase A does not play a role. In conclusion, this study suggests a novel sAC-dependent signaling pathway that controls the proliferation of prostate carcinoma cells.
Yury Ladilov - One of the best experts on this subject based on the ideXlab platform.
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protective role of Soluble Adenylyl Cyclase against reperfusion induced injury of cardiac cells
Biochimica et Biophysica Acta, 2019Co-Authors: Laura Rinaldi, Sofya Pozdniakova, Vignesh Jayarajan, Christian Troidl, Yaser Abdallah, Muhammad Aslam, Yury LadilovAbstract:Abstract Aims Disturbance of mitochondrial function significantly contributes to the myocardial injury that occurs during reperfusion. Increasing evidence suggests a role of intra-mitochondrial cyclic AMP (cAMP) signaling in promoting respiration and ATP synthesis. Mitochondrial levels of cAMP are controlled by type 10 Soluble Adenylyl Cyclase (sAC) and phosphodiesterase 2 (PDE2), however their role in the reperfusion-induced injury remains unknown. Here we aimed to examine whether sAC may support cardiomyocyte survival during reperfusion. Methods and results Adult rat cardiomyocytes or rat cardiac H9C2 cells were subjected to metabolic inhibition and recovery as a model of simulated ischemia and reperfusion. Cytosolic Ca2+, pH, mitochondrial cAMP (live-cell imaging), and cell viability were analyzed during a 15-min period of reperfusion. Suppression of sAC activity in cardiomyocytes and H9C2 cells, either by sAC knockdown, by pharmacological inhibition or by withdrawal of bicarbonate, a natural sAC activator, compromised cell viability and recovery of cytosolic Ca2+ homeostasis during reperfusion. Contrariwise, overexpression of mitochondria-targeted sAC in H9C2 cells suppressed reperfusion-induced cell death. Analyzing cAMP concentration in mitochondrial matrix we found that inhibition of PDE2, a predominant mitochondria-localized PDE isoform in mammals, during reperfusion significantly increased cAMP level in mitochondrial matrix, but not in cytosol. Accordingly, PDE2 inhibition attenuated reperfusion-induced cardiomyocyte death and improved recovery of the cytosolic Ca2+ homeostasis. Conclusion sAC plays an essential role in supporting cardiomyocytes viability during reperfusion. Elevation of mitochondrial cAMP pool either by sAC overexpression or by PDE2 inhibition beneficially affects cardiomyocyte survival during reperfusion.
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role of Soluble Adenylyl Cyclase in cell death and growth
Biochimica et Biophysica Acta, 2014Co-Authors: Yury Ladilov, Avinash AppukuttanAbstract:cAMP signaling is an evolutionarily conserved intracellular communication system controlling numerous cellular functions. Until recently, transmembrane Adenylyl Cyclase (tmAC) was considered the major source for cAMP in the cell, and the role of cAMP signaling was therefore attributed exclusively to the activity of this family of enzymes. However, increasing evidence demonstrates the role of an alternative, intracellular source of cAMP produced by type 10 Soluble Adenylyl Cyclase (sAC). In contrast to tmAC, sAC produces cAMP in various intracellular microdomains close to specific cAMP targets, e.g., in nucleus and mitochondria. Ongoing research demonstrates involvement of sAC in diverse physiological and pathological processes. The present review is focused on the role of cAMP signaling, particularly that of sAC, in cell death and growth. Although the contributions of sAC to the regulation of these cellular functions have only recently been discovered, current data suggest that sAC plays key roles in mitochondrial bioenergetics and the mitochondrial apoptosis pathway, as well as cell proliferation and development. Furthermore, recent reports suggest the importance of sAC in several pathologies associated with apoptosis as well as in oncogenesis. This article is part of a Special Issue entitled: The role of Soluble Adenylyl Cyclase in health and disease.
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inhibition of Soluble Adenylyl Cyclase increases the radiosensitivity of prostate cancer cells
Biochimica et Biophysica Acta, 2014Co-Authors: Avinash Appukuttan, Yury Ladilov, Janpaul Flacke, Hanna Flacke, Alexandra Posadowsky, Peter H ReuschAbstract:Pharmacological modulation of tumor radiosensitivity is a promising strategy for enhancing the outcome of radiotherapy. cAMP signaling plays an essential role in modulating the proliferation and apoptosis of different cell types, including cancer cells. Until now, the regulation of this pathway was restricted to the transmembrane class of Adenylyl Cyclases. In the present study, the role of an alternative source of cAMP, the intracellular localized Soluble Adenylyl Cyclase (sAC), in the radiosensitivity of prostate cancer cells was investigated. Pharmacological inhibition of sAC activity led to marked suppression of proliferation, lactate dehydrogenase release, and induction of apoptosis. The combination of ionizing radiation with partial suppression of sAC activity (~50%) immediately after irradiation synergistically inhibited proliferation and induced apoptosis. Overexpression of sAC in normal prostate epithelial PNT2 cells increased the cAMP content and accelerated cell proliferation under control conditions. The effects of radiation were significantly reduced in transformed PNT2 cells compared with control cells. Analysis of the underlying cellular mechanisms of sAC-induced radioresistance revealed the sAC-dependent activation of B-Raf/ERK1/2 signaling. In agreement with this finding, inhibition of ERK1/2 in prostate cancer cells enhanced the cytotoxic effect of irradiation. In conclusion, the present study suggests that sAC-dependent signaling plays an important role in the radioresistance of prostate cancer cells. This article is part of a Special Issue entitled: The role of Soluble Adenylyl Cyclase in health and disease.
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oxysterol induced apoptosis of smooth muscle cells is under the control of a Soluble Adenylyl Cyclase
Cardiovascular Research, 2013Co-Authors: Avinash Appukuttan, Peter H Reusch, Sanjeev Kumar, Sascha A Kasseckert, Yury LadilovAbstract:Aims Apoptosis of vascular smooth muscle cells (VSMC) in advanced atherosclerotic plaques is an important cause of plaque instability. Oxysterols have been suggested as important inducers of apoptosis in VSMC, but the precise mechanism is still poorly understood. Here we aimed to analyse the role of the Soluble Adenylyl Cyclase (sAC). Methods and results VSMC derived from rat aorta were treated with either 25-hydroxycholesterol or 7-ketocholesterol for 24 h. Apoptosis was detected by TUNEL staining and caspases cleavage. Oxysterols treatment led to the activation of the mitochondrial pathway of apoptosis (cytochrome c release and caspase-9 cleavage) and mitochondrial ROS formation, which were suppressed by the pharmacological inhibition or knockdown of sAC. Scavenging ROS with N -acetyl-l-cysteine prevented oxysterol-induced apoptosis. Analyses of the downstream pathway suggest that protein kinase A (PKA)-dependent phosphorylation and the mitochondrial translocation of the pro-apoptotic protein Bax is a key link between sAC and oxysterol-induced ROS formation and apoptosis. To distinguish between intra-mitochondrial and extra-mitochondrial/cytosolic sAC pools, sAC was overexpressed in mitochondria or in the cytosol. sAC expression in the cytosol, but not in mitochondria, significantly promoted apoptosis and ROS formation during oxysterol treatment. Conclusion These results suggest that the sAC/PKA axis plays a key role in the oxysterol-induced apoptosis of VSMC by controlling mitochondrial Bax translocation and ROS formation and that cytosolic sAC, rather than the mitochondrial pool, is involved in the apoptotic mechanism.
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type 10 Soluble Adenylyl Cyclase is overexpressed in prostate carcinoma and controls proliferation of prostate cancer cells
Journal of Biological Chemistry, 2013Co-Authors: Janpaul Flacke, Jonathan H. Zippin, Avinash Appukuttan, Hanna Flacke, Peter H Reusch, Reinjuri Palisaar, Joachim Noldus, Brian D Robinson, Yury LadilovAbstract:cAMP signaling plays an essential role in modulating the proliferation of different cell types, including cancer cells. Until now, the regulation of this pathway was restricted to the transmembrane class of Adenylyl Cyclases. In this study, significant overexpression of Soluble Adenylyl Cyclase (sAC), an alternative source of cAMP, was found in human prostate carcinoma, and therefore, the contribution of this Cyclase was investigated in the prostate carcinoma cell lines LNCaP and PC3. Suppression of sAC activity by treatment with the sAC-specific inhibitor KH7 or by sAC-specific knockdown mediated by siRNA or shRNA transfection prevented the proliferation of prostate carcinoma cells, led to lactate dehydrogenase release, and induced apoptosis. Cell cycle analysis revealed a significant rise in the G2 phase population 12 h after sAC inhibition, which was accompanied by the down-regulation of cyclin B1 and CDK1. sAC-dependent regulation of proliferation involves the EPAC/Rap1/B-Raf signaling pathway. In contrast, protein kinase A does not play a role. In conclusion, this study suggests a novel sAC-dependent signaling pathway that controls the proliferation of prostate carcinoma cells. Background: Soluble Adenylyl Cyclase (sAC) may be an alternative intracellular localized source of cAMP controlling proliferation. Results: sAC is overexpressed in prostate carcinoma, and inhibition of sAC leads to cell cycle arrest. Conclusion: sAC controls proliferation of prostate carcinoma cells. Significance: sAC represents a novel pathway promoting proliferation in cancer cells and is a promising target for prostate cancer treatment.
