scholarly journals Studying signal compartmentation in adult cardiomyocytes

2020 ◽  
Vol 48 (1) ◽  
pp. 61-70 ◽  
Author(s):  
Aleksandra Judina ◽  
Julia Gorelik ◽  
Peter T. Wright
Keyword(s):  
Fluorescent Dyes ◽  
Fluorescent Proteins ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Cell Types ◽  
Functional Responses ◽  
Relative Contribution ◽  
New Perspective ◽  
Active Processes ◽  
Cell To Cell Variability

Multiple intra-cellular signalling pathways rely on calcium and 3′–5′ cyclic adenosine monophosphate (cAMP) to act as secondary messengers. This is especially true in cardiomyocytes which act as the force-producing units of the cardiac muscle and are required to react rapidly to environmental stimuli. The specificity of functional responses within cardiomyocytes and other cell types is produced by the organellar compartmentation of both calcium and cAMP. In this review, we assess the role of molecular localisation and relative contribution of active and passive processes in producing compartmentation. Active processes comprise the creation and destruction of signals, whereas passive processes comprise the release or sequestration of signals. Cardiomyocytes display a highly articulated membrane structure which displays significant cell-to-cell variability. Special attention is paid to the way in which cell membrane caveolae and the transverse-axial tubule system allow molecular localisation. We explore the effects of cell maturation, pathology and regional differences in the organisation of these processes. The subject of signal compartmentation has had a significant amount of attention within the cardiovascular field and has undergone a revolution over the past two decades. Advances in the area have been driven by molecular imaging using fluorescent dyes and genetically encoded constructs based upon fluorescent proteins. We also explore the use of scanning probe microscopy in the area. These techniques allow the analysis of molecular compartmentation within specific organellar compartments which gives researchers an entirely new perspective.

scholarly journals Priming innate immune responses to infection by cyclooxygenase inhibition kills antibiotic-susceptible and -resistant bacteria

Blood ◽  
2010 ◽  
Vol 116 (16) ◽  
pp. 2950-2959 ◽  
Author(s):  
Melanie J. Stables ◽  
Justine Newson ◽  
Samir S. Ayoub ◽  
Jeremy Brown ◽  
Catherine J. Hyams ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Innate Immune ◽  
Host Responses ◽  
Resistant Bacteria ◽  
Reactive Oxygen Intermediate ◽  
Dependent Manner ◽  
Bacterial Killing ◽  
Relative Contribution

AbstractInhibition of cyclooxygenase (COX)–derived prostaglandins (PGs) by nonsteroidal anti-inflammatory drugs (NSAIDs) mediates leukocyte killing of bacteria. However, the relative contribution of COX1 versus COX2 to this process, as well as the mechanisms controlling it in mouse and humans, are unknown. Indeed, the potential of NSAIDs to facilitate leukocyte killing of drug-resistant bacteria warrants investigation. Therefore, we carried out a series of experiments in mice and humans, finding that COX1 is the predominant isoform active in PG synthesis during infection and that its prophylactic or therapeutic inhibition primes leukocytes to kill bacteria by increasing phagocytic uptake and reactive oxygen intermediate-mediated killing in a cyclic adenosine monophosphate (cAMP)-dependent manner. Moreover, NSAIDs enhance bacterial killing in humans, exerting an additive effect when used in combination with antibiotics. Finally, NSAIDs, through the inhibition of COX prime the innate immune system to mediate bacterial clearance of penicillin-resistant Streptococcus pneumoniae serotype 19A, a well-recognized vaccine escape serotype of particular concern given its increasing prevalence and multi-antibiotic resistance. Therefore, these data underline the importance of lipid mediators in host responses to in-fection and the potential of inhibitors of PG signaling pathways as adjunc-tive therapies, particularly in the con-text of antibiotic resistance.

scholarly journals Cooperation of the haves and the have-nots

2017 ◽  
Author(s):  
Kaumudi H Prabhakara ◽  
Albert J Bae ◽  
Eberhard Bodenschatz
Keyword(s):  
Social Behavior ◽  
Dictyostelium Discoideum ◽  
Large Scale ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Divalent Ions ◽  
Complementary Resources ◽  
Degradation Rates ◽  
Chemical Messenger ◽  
Cell To Cell Variability

AbstractUpon starvation, Dictyostelium discoideum (D.d.) exhibit social behavior mediated by the chemical messenger cyclic adenosine monophosphate (cAMP). Large scale cAMP waves synchronize the population of starving cells and enable them to aggregate and form a multi-cellular organism. Here, we explore the effect of cell-to-cell variability in the production of cAMP on aggregation. We create a mixture of extreme cell-to-cell variability by mixing a few cells that produce cAMP (haves) with a majority of mutants that cannot produce cAMP (have-nots). Surprisingly, such mixtures aggregate, although each population on its own cannot aggregate. We show that (1) a lack of divalent ions kills the haves at low densities and (2) the have-nots supply the cAMP degrading enzyme, phosphodiesterase, which, in the presence of divalent ions, enables the mixture to aggregate. Our results suggest that a range of degradation rates induces optimal aggregation. The haves and the have-nots cooperate by sharing complementary resources.

scholarly journals Live-Cell Imaging Probes to Track Chromatin Modification Dynamics

Microscopy ◽  
2021 ◽  
Author(s):  
Yuko Sato ◽  
Masaru Nakao ◽  
Hiroshi Kimura
Keyword(s):  
Fluorescent Dyes ◽  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Chromatin Modification ◽  
Resonance Energy ◽  
Cell Types ◽  
Live Cell ◽  
Chromatin Modifications ◽  
Chromatin Regulation ◽  
Single Chain

Abstract The spatiotemporal organization of chromatin is regulated at different levels in the nucleus. Epigenetic modifications such as DNA methylation and histone modifications are involved in chromatin regulation and play fundamental roles in genome function. While the one-dimensional epigenomic landscape in many cell types has been revealed by chromatin immunoprecipitation and sequencing, the dynamic changes of chromatin modifications and their relevance to chromatin organization and genome function remain elusive. Live-cell probes to visualize chromatin and its modifications have become powerful tools to monitor dynamic chromatin regulation. Bulk chromatin can be visualized both by small fluorescent dyes and fluorescent proteins, and specific endogenous genomic loci have been detected by adapting genome-editing tools. To track chromatin modifications in living cells, various types of probes have been developed. Protein domains that bind to specific modifications weakly, such as chromodomains for histone methylation, can be repeated to create a tighter binding probe that can then be tagged with a fluorescent protein. It has also been demonstrated that antigen-binding fragments and single-chain variable fragments from modification-specific antibodies can serve as binding probes without disturbing cell division, development and, differentiation. These modification-binding modules are used in modification sensors based on fluorescence/Förster resonance energy transfer to measure the intramolecular conformation changes triggered by modifications. Other probes can be created using a bivalent binding system, such as fluorescence complementation, or luciferase chemiluminescence. Live-cell chromatin modification imaging using these probes will address dynamic chromatin regulation and will be useful for assaying and screening effective epigenome drugs in cells and organisms.

scholarly journals Transcription factors regulated by cAMP in smooth muscle of the myometrium at human parturition

2021 ◽  
Vol 49 (2) ◽  
pp. 997-1011
Author(s):  
Jonathan K.H. Li ◽  
Pei F. Lai ◽  
Rachel M. Tribe ◽  
Mark R. Johnson
Keyword(s):  
Smooth Muscle ◽  
Progesterone Receptors ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Cell Types ◽  
Nuclear Factor Κb ◽  
Activator Protein 1 ◽  
Camp Response Element ◽  
Expression Of Genes ◽  
Human Parturition

Cyclic adenosine monophosphate (cAMP) contributes to maintenance of a quiescent (relaxed) state in the myometrium (i.e. uterine smooth muscle) during pregnancy, which most commonly has been attributed to activation of protein kinase A (PKA). PKA-mediated phosphorylation of cytosolic contractile apparatus components in myometrial smooth muscle cells (mSMCs) are known to promote relaxation. Additionally, PKA also regulates nuclear transcription factor (TF) activity to control expression of genes important to the labour process; these are mostly involved in actin-myosin interactions, cell-to-cell connectivity and inflammation, all of which influence mSMC transition from a quiescent to a contractile (pro-labour) phenotype. This review focuses on the evidence that cAMP modulates the activity of TFs linked to pro-labour gene expression, predominantly cAMP response element (CRE) binding TFs, nuclear factor κB (NF-κB), activator protein 1 (AP-1) family and progesterone receptors (PRs). This review also considers the more recently described exchange protein directly activated by cAMP (EPAC) that may oppose the pro-quiescent effects of PKA, as well as explores findings from other cell types that have the potential to be of novel relevance to cAMP action on TF function in the myometrium.

Primary Cilia Mediate Intracellular cAMP Responses in Bone Cells Exposed to Dynamic Fluid Flow

2008 ◽  
Author(s):  
Ronald Y. Kwon ◽  
Sara Temiyasathit ◽  
Padmaja Tummala ◽  
Clarence Quah ◽  
Christopher R. Jacobs
Keyword(s):  
Fluid Flow ◽  
Primary Cilia ◽  
Bone Structure ◽  
Bone Cells ◽  
Cyclic Adenosine Monophosphate ◽  
Second Messenger ◽  
Adenosine Monophosphate ◽  
Cell Types ◽  
Intracellular Camp ◽  
And Function

It is well accepted that fluid flow is an important mechanical signal in regulating bone structure and function. Primary cilia, which are non-motile, microtubule based organelles that extend from the centrosome and project into extracellular space in many cell types, have recently been shown to mediate fluid flow-induced osteogenic responses in MLO-Y4 osteocyte-like cells [1]. However, primary cilia did not mediate increases in intracellular Ca2+ concentration, and the second messenger system(s) involved in primary cilia-mediated mechanosensing has yet to be elucidated. In this study, our goals were to (1) determine whether exposing bone cells to oscillatory fluid flow modulates intracellular levels of cyclic adenosine monophosphate (cAMP), another ubiquitous second messenger molecule, and (2) investigate whether this modulation may be mediated by primary cilia.

scholarly journals Extracellular vesicles: another compartment for the second messenger, cyclic adenosine monophosphate

2019 ◽  
Vol 316 (4) ◽  
pp. L691-L700 ◽  
Author(s):  
Sarah L. Sayner ◽  
Chung-Sik Choi ◽  
Marcy E. Maulucci ◽  
K. C. Ramila ◽  
Chun Zhou ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Extracellular Vesicles ◽  
Cell Communication ◽  
Cyclic Adenosine Monophosphate ◽  
Second Messenger ◽  
Adenosine Monophosphate ◽  
Cell Types ◽  
Signaling Specificity ◽  
Phosphodiesterase 4 ◽  
Pulmonary Endothelial Cells

The second messenger, cAMP, is highly compartmentalized to facilitate signaling specificity. Extracellular vesicles (EVs) are submicron, intact vesicles released from many cell types that can act as biomarkers or be involved in cell-to-cell communication. Although it is well recognized that EVs encapsulate functional proteins and RNAs/miRNAs, currently it is unclear whether cyclic nucleotides are encapsulated within EVs to provide an additional second messenger compartment. Using ultracentrifugation, EVs were isolated from the culture medium of unstimulated systemic and pulmonary endothelial cells. EVs were also isolated from pulmonary microvascular endothelial cells (PMVECs) following stimulation of transmembrane adenylyl cyclase (AC) in the presence or absence of the phosphodiesterase 4 inhibitor rolipram over time. Whereas cAMP was detected in EVs isolated from endothelial cells derived from different vascular beds, it was highest in EVs isolated from PMVECs. Treatment of PMVECs with agents that increase near-membrane cAMP led to an increase in cAMP within corresponding EVs, yet there was no increase in EV number. Elevated cell cAMP, measured by whole cell measurements, peaked 15 min after treatment, yet in EVs the peak increase in cAMP was delayed until 60 min after cell stimulation. Cyclic AMP was also increased in EVs collected from the perfusate of isolated rat lungs stimulated with isoproterenol and rolipram, thus corroborating cell culture findings. When added to unperturbed confluent PMVECs, EVs containing elevated cAMP were not barrier disruptive like cytosolic cAMP but maintained monolayer resistance. In conclusion, PMVECs release EVs containing cAMP, providing an additional compartment to cAMP signaling.

scholarly journals . Effect of fluoxetine on the inhibition of adenylate cyclase activity in foskolin-stimulated MLTC-1 leydig cells

2020 ◽  
Vol 17 (4) ◽  
pp. 595-602
Author(s):  
Nguyen Thi Mong Diep ◽  
Nguyen Thi Bich Hang ◽  
Nguyen Le Cong Minh ◽  
Tran Thanh Son ◽  
Nguyen Thuy Duong
Keyword(s):  
Cyclic Amp ◽  
Leydig Cells ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Cell Types ◽  
Intracellular Camp ◽  
Atp Levels ◽  
Long Time ◽  
Short Time ◽  
Camp Levels

Fluoxetine (FLX), a widely used antidepressant primarily acting as a selective serotonin reuptake inhibitor, has been shown to exhibit other mechanisms of action in various cell types. Cyclic adenosine monophosphate (cAMP) is a second messenger used for intracellular signal induction. Cyclic AMP is a nucleotide synthesized within the cell from adenosine triphosphate by the adenylyl cyclase enzyme, and is inactivated enzymatically to 5′AMP by hydroxylation with a group of enzymes called phosphodiesterase. The aim of this study was to determine the effects of FLX on MLTC-1 Leydig cells on intracellular cyclic AMP response to forskolin (FSK). MLTC-1 cells were incubated at 37°C in media supplemented with or without different doses of FLX (0, 0.156, 0.3125, 0.625, 1.25, 2.5, 5 and 10 µM). We then looked for how the concentration of FLX for a short-time (2 hours) and a long-time (24 hours) affects the concentration of intracellular cyclic AMP response to FSK and ATP levels on MLTC-1 cells. Our results show that FLX decreased the intracellular cAMP response to FSK depending on FLX concentration. FLX decreased significantly cAMP levels only at 10 µM after 2 hours of incubation but after 24 hours of incubation FLX caused an effect on cAMP levels at 5 µM and at 10 µM. Moreover, as expected, FLX also caused a decline of steroidogenesis, which is under the control of cAMP and ATP levels in the cells. Taken together, these findings demonstrate that the inhibition of cAMP synthesis by FLX is dose-dependent, and that FLX also inhibited hormone-induced steroidogenesis in MLTC-1 cells.

scholarly journals PACmn for improved optogenetic control of intracellular cAMP

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Shang Yang ◽  
Oana M. Constantin ◽  
Divya Sachidanandan ◽  
Hannes Hofmann ◽  
Tobias C. Kunz ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Signaling Pathways ◽  
Hippocampal Neurons ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Cell Types ◽  
Camp Signaling ◽  
Intracellular Camp ◽  
Extracellular Signals ◽  
Starting Point

Abstract Background Cyclic adenosine monophosphate (cAMP) is a ubiquitous second messenger that transduces extracellular signals in virtually all eukaryotic cells. The soluble Beggiatoa photoactivatable adenylyl cyclase (bPAC) rapidly raises cAMP in blue light and has been used to study cAMP signaling pathways cell-autonomously. But low activity in the dark might raise resting cAMP in cells expressing bPAC, and most eukaryotic cyclases are membrane-targeted rather than soluble. Our aim was to engineer a plasma membrane-anchored PAC with no dark activity (i.e., no cAMP accumulation in the dark) that rapidly increases cAMP when illuminated. Results Using a streamlined method based on expression in Xenopus oocytes, we compared natural PACs and confirmed bPAC as the best starting point for protein engineering efforts. We identified several modifications that reduce bPAC dark activity. Mutating a phenylalanine to tyrosine at residue 198 substantially decreased dark cyclase activity, which increased 7000-fold when illuminated. Whereas Drosophila larvae expressing bPAC in mechanosensory neurons show nocifensive-like behavior even in the dark, larvae expressing improved soluble (e.g., bPAC(R278A)) and membrane-anchored PACs exhibited nocifensive responses only when illuminated. The plasma membrane-anchored PAC (PACmn) had an undetectable dark activity which increased >4000-fold in the light. PACmn does not raise resting cAMP nor, when expressed in hippocampal neurons, affect cAMP-dependent kinase (PKA) activity in the dark, but rapidly and reversibly increases cAMP and PKA activity in the soma and dendrites upon illumination. The peak responses to brief (2 s) light flashes exceed the responses to forskolin-induced activation of endogenous cyclases and return to baseline within seconds (cAMP) or ~10 min (PKA). Conclusions PACmn is a valuable optogenetic tool for precise cell-autonomous and transient stimulation of cAMP signaling pathways in diverse cell types.

scholarly journals 60 YEARS OF POMC: Adrenal and extra-adrenal functions of ACTH

2016 ◽  
Vol 56 (4) ◽  
pp. T135-T156 ◽  
Author(s):  
Nicole Gallo-Payet
Keyword(s):  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Cell Types ◽  
Signaling Cascades ◽  
Steroid Secretion ◽  
Chronic Effects ◽  
Acth Receptor ◽  
Messenger System ◽  
Pituitary Adrenal Axis

The pituitary adrenocorticotropic hormone (ACTH) plays a pivotal role in homeostasis and stress response and is thus the major component of the hypothalamo–pituitary–adrenal axis. After a brief summary of ACTH production from proopiomelanocortin (POMC) and on ACTH receptor properties, the first part of the review covers the role of ACTH in steroidogenesis and steroid secretion. We highlight the mechanisms explaining the differential acute vs chronic effects of ACTH on aldosterone and glucocorticoid secretion. The second part summarizes the effects of ACTH on adrenal growth, addressing its role as either a mitogenic or a differentiating factor. We then review the mechanisms involved in steroid secretion, from the classical Cyclic adenosine monophosphate second messenger system to various signaling cascades. We also consider how the interaction between the extracellular matrix and the cytoskeleton may trigger activation of signaling platforms potentially stimulating or repressing the steroidogenic potency of ACTH. Finally, we consider the extra-adrenal actions of ACTH, in particular its role in differentiation in a variety of cell types, in addition to its known lipolytic effects on adipocytes. In each section, we endeavor to correlate basic mechanisms of ACTH function with the pathological consequences of ACTH signaling deficiency and of overproduction of ACTH.

Sign in / Sign up

Export Citation Format

Share Document