scholarly journals Ryanodine Receptor Type 2: A Molecular Target for Dichlorodiphenyltrichloroethane (DDT)- and Dichlorodiphenyldichloroethylene (DDE)-Mediated Cardiotoxicity

2020 ◽  
Author(s):  
Kim M Truong ◽  
Wei Feng ◽  
Isaac N Pessah
Keyword(s):  
Ryanodine Receptor ◽  
Cardiac Tissue ◽  
Induced Pluripotent Stem Cell ◽  
Receptor Type ◽  
Wildtype Mouse ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Human Cardiomyocytes ◽  
Pre Treatment

Abstract Dichlorodiphenyltrichloroethane (DDT) and its metabolite dichlorodiphenyl-dichloroethylene (DDE) are ubiquitously found in the environment and linked to cardiovascular diseases (CVDs) – with a majority of the work focused on hypertension. Studies investigating whether DDx can interact with molecular targets on cardiac tissue to directly affect cardiac function are lacking. Therefore, we investigated whether o,p’-DDT, p,p’-DDT, o,p’-DDE, or p,p’-DDE (DDx, collectively) can directly alter the function of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) by assessing their effect(s) on hiPSC-CMs Ca2+ dynamics. DDx (0.1-10 µM) affected hiPSC-CMs synchronous Ca2+ oscillation (SCO) frequency in a concentration-dependent manner, with p,p’-DDT and p,p’-DDE also decreasing Ca2+ stores. HEK-RyR2 cells cultured under antibiotic selection to induce expression of wildtype mouse ryanodine receptor type 2 are used to further investigate whether DDx alters hiPSC-CMs Ca2+ dynamics through engagement with ryanodine receptor type 2 (RyR2), a protein critical for cardiac muscle excitation-contraction coupling (ECC). Acute treatment with 10 µM DDx failed to induce Ca2+ release in HEK293-RyR2, whereas pre-treatment with DDx (0.1-10 µM) for 12- or 24-h significantly decreased SR Ca2+ stores in HEK-RyR2 cells challenged with caffeine (1 mM), an RyR agonist. [3H]ryanodine binding analysis using murine cardiac RyR2 homogenates further confirmed that all DDx isomers (10 µM) can directly engage with RyR2 to favor an open (leaky) confirmation, whereas only the DDT isomers (10 µM) modestly (≤10%) inhibited SERCA2a activity. The data demonstrate that DDx increases heart rate and depletes Ca2+ stores in human cardiomyocytes through a mechanism that impairs RyR2 function and Ca2+ dynamics.

scholarly journals Interactions of Dichlorodiphenyltrichloroethane (DDT) and Dichlorodiphenyldichloroethylene (DDE) With Skeletal Muscle Ryanodine Receptor Type 1

2019 ◽  
Vol 170 (2) ◽  
pp. 509-524
Author(s):  
Kim M Truong ◽  
Gennady Cherednichenko ◽  
Isaac N Pessah
Keyword(s):  
Skeletal Muscle ◽  
Ryanodine Receptor ◽  
Membrane Vesicles ◽  
Receptor Type ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Voltage Gated Sodium Channels ◽  
Muscle Health ◽  
Living Organisms

Abstract Dichlorodiphenyltrichloroethane (DDT) and its metabolite dichlorodiphenyldichloroethylene (DDE) are ubiquitous in the environment and detected in tissues of living organisms. Although DDT owes its insecticidal activity to impeding closure of voltage-gated sodium channels, it mediates toxicity in mammals by acting as an endocrine disruptor (ED). Numerous studies demonstrate DDT/DDE to be EDs, but studies examining muscle-specific effects mediated by nonhormonal receptors in mammals are lacking. Therefore, we investigated whether o,p′-DDT, p,p′-DDT, o,p′-DDE, and p,p′-DDE (DDx, collectively) alter the function of ryanodine receptor type 1 (RyR1), a protein critical for skeletal muscle excitation-contraction coupling and muscle health. DDx (0.01–10 µM) elicited concentration-dependent increases in [3H]ryanodine ([3H]Ry) binding to RyR1 with o,p′-DDE showing highest potency and efficacy. DDx also showed sex differences in [3H]Ry-binding efficacy toward RyR1, where [3H]Ry-binding in female muscle preparations was greater than male counterparts. Measurements of Ca2+ transport across sarcoplasmic reticulum (SR) membrane vesicles further confirmed DDx can selectively engage with RyR1 to cause Ca2+ efflux from SR stores. DDx also disrupts RyR1-signaling in HEK293T cells stably expressing RyR1 (HEK-RyR1). Pretreatment with DDx (0.1–10 µM) for 100 s, 12 h, or 24 h significantly sensitized Ca2+-efflux triggered by RyR agonist caffeine in a concentration-dependent manner. o,p′-DDE (24 h; 1 µM) significantly increased Ca2+-transient amplitude from electrically stimulated mouse myotubes compared with control and displayed abnormal fatigability. In conclusion, our study demonstrates DDx can directly interact and modulate RyR1 conformation, thereby altering SR Ca2+-dynamics and sensitize RyR1-expressing cells to RyR1 activators, which may ultimately contribute to long-term impairments in muscle health.

scholarly journals Orexin depolarizes rat hypothalamic paraventricular nucleus neurons

2001 ◽  
Vol 281 (4) ◽  
pp. R1114-R1118 ◽  
Author(s):  
Tetsuro Shirasaka ◽  
Satoshi Miyahara ◽  
Takato Kunitake ◽  
Qing-Hua Jin ◽  
Kazuo Kato ◽  
...  
Keyword(s):  
Paraventricular Nucleus ◽  
Brain Slices ◽  
Hypothalamic Paraventricular Nucleus ◽  
Dependent Manner ◽  
Patch Clamp Recording ◽  
Concentration Dependent Manner ◽  
Whole Cell Patch Clamp ◽  
Orexin Receptors ◽  
Bath Application

Orexins, also called hypocretins, are newly discovered hypothalamic peptides that are thought to be involved in various physiological functions. In spite of the fact that orexin receptors, especially orexin receptor 2, are abundant in the hypothalamic paraventricular nucleus (PVN), the effects of orexins on PVN neurons remain unknown. Using a whole cell patch-clamp recording technique, we investigated the effects of orexin-B on PVN neurons of rat brain slices. Bath application of orexin-B (0.01–1.0 μM) depolarized 80.8% of type 1 ( n = 26) and 79.2% of type 2 neurons tested ( n = 24) in the PVN in a concentration-dependent manner. The effects of orexin-B persisted in the presence of TTX (1 μM), indicating that these depolarizing effects were generated postsynaptically. Addition of Cd2+(1 mM) to artificial cerebrospinal fluid containing TTX (1 μM) significantly reduced the depolarizing effect in type 2 neurons. These results suggest that orexin-B has excitatory effects on the PVN neurons mediated via a depolarization of the membrane potential.

Abstract P808: The Main Peptide Ssubstrates of Neurolysin Enhance Brain Microvascular Permeability in a Human in vitro Model

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Abraham Al-Ahmad ◽  
Vardan T Karamyan
Keyword(s):  
Direct Action ◽  
Induced Pluripotent Stem Cell ◽  
Microvascular Permeability ◽  
Dependent Manner ◽  
Direct Effects ◽  
Edema Formation ◽  
Concentration Dependent Manner ◽  
Therapeutic Implications ◽  
Bbb Permeability

Increased brain microvascular permeability and disruption of blood-brain barrier (BBB) function are among hallmarks of ischemic stroke. Recently, peptidase neurlysin (Nln) has been identified as a compensatory and cerebroprotective mechanism in the post-stroke brain that functions to process a diverse group of extracellular neuropeptides, including bradykinin (BK), neurotensin (NT) and substance P (SP). A number of studies suggest involvement of BK, NT and SP in BBB impairment and edema formation after stroke, however there is paucity of data in regards to the direct effects of these peptides on the brain microvascular endothelial cells (BMECs) and BBB. The purpose of this study was to evaluate the direct effects of BK, NT and SP on permeability of BBB in an in vitro model based on human, induced pluripotent stem cell (iPSC)-derived BMECs. Our data indicate that all three peptides increase BBB permeability in a concentration-dependent manner in an in vitro model formed from two different iPSC lines (CTR90F and CTR65M) and widely used hCMEC/D3 human BMECs. Combination of BK, NT and SP at a sub-effective concentration also resulted in increased BBB permeability in the iPSC-derived model. Furthermore, we observed abrogation of BK, NT and SP effects with pretreatment of pharmacological blockers targeting their specific receptors or in presence of recombinant neurolysin (Nln). This is the first experimental study to document increased permeability of BBB in response to direct action of NT in an in vitro model. In addition, our study confirms the expected but not well-documented, direct effect of SP on BBB permeability and adds to the well-recognized actions of BK on BBB. Lastly, we demonstrate that peptidase Nln can neutralize the effects of these peptides on BBB, suggesting potential therapeutic implications.

Junctophilin-2  physically interacts with ryanodine receptor type 2 for peripheral coupling of mouse cardiomyocytes

2020 ◽  
Author(s):  
Tianxia Luo ◽  
Ningning Yan ◽  
Mengru Xu ◽  
Fengjuan Dong ◽  
Qian Liang ◽  
...  
Keyword(s):  
Ryanodine Receptor ◽  
Bioinformatic Analysis ◽  
Cardiac Contraction ◽  
Receptor Type ◽  
Immunofluorescent Staining ◽  
Physical Interaction ◽  
C Terminus ◽  
Confocal Immunofluorescence ◽  
Intracellular Ca

Abstract Background: Ryanodine receptor type 2 (RyR2) mediate Ca 2+ release from the endoplasmic and sarcoplasmic reticulum (ER and SR), which is involved in the peripheral coupling of mouse cardiomyocytes, and thereby plays an important role in cardiac contraction. Junctophilin-2 (JPH2, JP2) is anchored to the plasma membrane (PM) and membranes of the ER and SR, and modulates intracellular Ca 2+ handling through regulation of RyR2. However, the potential RyR2 binding region of JPH2 is poorly understood. Methods: The interaction of JPH2 with RyR2 was studied using LC-MS/MS , bioinformatic analysis,co-immunoprecipitation studies in cardiac SR vesicles. GST-pull down analysis was performed to investigate the physical interaction between RyR2 and JPH2 fragments. Immunofluorescent staining was carried out to determine the colocalization of RyR2 and JPH2 in isolated mouse cardiomyocytes. Ion Optix photometry system was used to measure the levels of intracellular Ca 2+ transients in cardiomyocytes isolated from JPH2 knock down mice. Results: We report that (i) JPH2 interacts with RyR2 and (ii) the C terminus of the JPH2 protein can pull down RyR2 receptors. Confocal immunofluorescence imaging indicated that the majority of JPH2 and RyR2 proteins were colocalized near Z-lines. A decrease in the levels of JPH2 expression reduced the amplitude of Ca 2+ transients in cardiomyocytes. Conclusions: This study suggests that the C terminus domain of JPH2 is required for interactions with RyR2 in the context of peripheral coupling of mouse cardiomyocytes, which provide a molecular mechanism for looking for Ca 2+ - related diseases prevention strategies.

cADP-ribose releases Ca2+ from cardiac sarcoplasmic reticulum independently of ryanodine receptor

1997 ◽  
Vol 273 (3) ◽  
pp. H1082-H1089 ◽  
Author(s):  
P. Lahouratate ◽  
J. Guibert ◽  
J. F. Faivre
Keyword(s):  
Endoplasmic Reticulum ◽  
Sarcoplasmic Reticulum ◽  
Ryanodine Receptor ◽  
Sea Urchin ◽  
Calcium Release ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Cardiac Sarcoplasmic Reticulum ◽  
Consistent Effect ◽  
Cyclic Adp Ribose

Cyclic ADP-ribose (cADPR), an endogenous metabolite of beta-NAD+, activates Ca2+ release from endoplasmic reticulum in sea urchin eggs via the ryanodine receptor (RyR) pathway. A similar role has been proposed in cardiac sarcoplasmic reticulum (SR), although this remains controversial. We therefore investigated the ability of cADPR to induce Ca2+ release from canine cardiac SR microsomes using fluo 3 to monitor extravesicular Ca2+ concentration. We found that cADPR induced Ca2+ release in a concentration-dependent manner, whereas neither its precursor, NAD+, nor its metabolite, ADP-ribose, elicited a consistent effect. In addition, an additive effect on calcium release between cADPR and 9-Me-7-Br-eudistomin-D (MBED), an activator of RyR, was found as well as no cross-desensitization between cADPR and MBED. Specific blockers of the RyR did not abolish the cADPR-induced Ca2+ release. These results provide evidence for cADPR-induced Ca2+ release from dog cardiac SR via a novel mechanism which is independent of RyR activation.

Vesl/Homer proteins regulate ryanodine receptor type 2 function and intracellular calcium signaling

Cell Calcium ◽  
2003 ◽  
Vol 34 (3) ◽  
pp. 261-269 ◽  
Author(s):  
Jens H Westhoff ◽  
Sung-Yong Hwang ◽  
R Scott Duncan ◽  
Fumiko Ozawa ◽  
Pompeo Volpe ◽  
...  
Keyword(s):  
Calcium Signaling ◽  
Intracellular Calcium ◽  
Ryanodine Receptor ◽  
Receptor Type ◽  
Intracellular Calcium Signaling ◽  
Homer Proteins

scholarly journals Ryanodine Receptor Type 2 Is Required for the Development of Pressure Overload-Induced Cardiac Hypertrophy

Hypertension ◽  
2011 ◽  
Vol 58 (6) ◽  
pp. 1099-1110 ◽  
Author(s):  
Yunzeng Zou ◽  
Yanyan Liang ◽  
Hui Gong ◽  
Ning Zhou ◽  
Hong Ma ◽  
...  
Keyword(s):  
Cardiac Hypertrophy ◽  
Ryanodine Receptor ◽  
Pressure Overload ◽  
Receptor Type

scholarly journals Cross talk between polysulfide and nitric oxide in rat peritoneal mast cells

2016 ◽  
Vol 310 (11) ◽  
pp. C894-C902 ◽  
Author(s):  
Amira Moustafa ◽  
Yoshiaki Habara
Keyword(s):  
Nitric Oxide ◽  
Mast Cells ◽  
Ryanodine Receptor ◽  
Cross Talk ◽  
Receptor Blocker ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Peritoneal Mast Cells ◽  
Intracellular Ca ◽  
Rat Peritoneal Mast Cells

The aim of this study was to define the effects of polysulfide on intracellular Ca2+ concentration ([Ca2+]i) and the underlying machinery, especially from the hydrogen sulfide (H2S) and nitric oxide (NO) perspectives, in rat peritoneal mast cells. We found that a polysulfide donor, Na2S4, increased [Ca2+]i, which is both extracellular and intracellular Ca2+ dependent. Intracellular Ca2+ release induced by Na2S4 was attenuated by the addition of a ryanodine receptor blocker. A slow-releasing H2S donor, GYY4137, dose dependently increased [Ca2+]i that was independent from extracellular Ca2+ influx. The GYY4137-induced [Ca2+]i release was partially attenuated in the presence of the ryanodine receptor blocker. Both polysulfide and H2S donors increased the intracellular NO levels in DAF-2-loaded mast cells, which were abolished by an NO scavenger, cPTIO. Inhibition of NO synthase (NOS) significantly abolished the polysulfide- or H2S-donor-induced [Ca2+]i elevation in the absence of extracellular Ca2+. An NO donor, diethylamine (DEA) NONOate, increased [Ca2+]i in a concentration-dependent manner, in which both extracellular and intracellular Ca2+ are associated. At higher concentrations, the DEA NONOate-induced [Ca2+]i increases were attenuated in the absence of extracellular Ca2+ and by the addition of the ryanodine receptor blocker. H2S and NO dose dependently induced polysulfide production. Curiously, polysulfide, H2S, and NO donors had no effect on mast cell degranulation. Among synthases, cystathionine-γ-lyase, and neuronal NOS seemed to be the major H2S- and NO-producing synthases, respectively. These results indicate that polysulfide acts as a potential signaling molecule that regulates [Ca2+]i homeostasis in rat peritoneal mast cells via a cross talk with NO and H2S.

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