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The FEBS Journal Nov 2023We previously identified glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as one of the cyclic adenosine diphosphoribose (cADPR)'s binding proteins and found that GAPDH...
We previously identified glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as one of the cyclic adenosine diphosphoribose (cADPR)'s binding proteins and found that GAPDH participates in cADPR-mediated Ca release from endoplasmic reticulum via ryanodine receptors (RyRs). Here, we aimed to chemically synthesise and pharmacologically characterise novel cADPR analogues. Based on the simulated cADPR-GAPDH complex structure, we performed the structure-based drug screening, identified several small chemicals with high docking scores to cADPR's binding pocket in GAPDH and showed that two of these compounds, C244 and C346, are potential cADPR antagonists. We further synthesised several analogues of C346 and found that its analogue, G42, also mobilised Ca release from lysosomes. G42 alkalised lysosomal pH and inhibited autophagosome-lysosome fusion. Moreover, G42 markedly inhibited Zika virus (ZIKV, a flavivirus) or murine hepatitis virus (MHV, a β-coronavirus) infections of host cells. These results suggest that G42 inhibits virus infection, likely by triggering lysosomal Ca mobilisation and inhibiting autophagy.
Topics: Animals; Mice; Humans; Calcium; Cyclic ADP-Ribose; Zika Virus Infection; Zika Virus; Ryanodine Receptor Calcium Release Channel; Autophagy; Lysosomes; Adenosine Diphosphate Ribose
PubMed: 37528513
DOI: 10.1111/febs.16920 -
Advances in Experimental Medicine and... 2020In mammalian cardiomyocytes, Ca influx through L-type voltage-gated Ca channels (VGCCs) is amplified by release of Ca via type 2 ryanodine receptors (RyR2) in the...
In mammalian cardiomyocytes, Ca influx through L-type voltage-gated Ca channels (VGCCs) is amplified by release of Ca via type 2 ryanodine receptors (RyR2) in the sarcoplasmic reticulum (SR): a process termed Ca-induced Ca-release (CICR). In mammalian skeletal muscles, VGCCs play a distinct role as voltage-sensors, physically interacting with RyR1 channels to initiate Ca release in a mechanism termed depolarisation-induced Ca-release (DICR). In the current study, we surveyed the genomes of animals and their close relatives, to explore the evolutionary history of genes encoding three proteins pivotal for ECC: L-type VGCCs; RyRs; and a protein family that anchors intracellular organelles to plasma membranes, namely junctophilins (JPHs). In agreement with earlier studies, we find that non-vertebrate eukaryotes either lack VGCCs, RyRs and JPHs; or contain a single homologue of each protein. Furthermore, the molecular features of these proteins thought to be essential for DICR are only detectable within vertebrates and not in any other taxonomic group. Consistent with earlier physiological and ultrastructural observations, this suggests that CICR is the most basal form of ECC and that DICR is a vertebrate innovation. This development was accompanied by the appearance of multiple homologues of RyRs, VGCCs and junctophilins in vertebrates, thought to have arisen by 'whole genome replication' mechanisms. Subsequent gene duplications and losses have resulted in distinct assemblies of ECC components in different vertebrate clades, with striking examples being the apparent absence of RyR2 from amphibians, and additional duplication events for all three ECC proteins in teleost fish. This is consistent with teleosts possessing the most derived mode of DICR, with their Ca1.1 VGCCs completely lacking in Ca channel activity.
Topics: Animals; Calcium Channels, L-Type; Evolution, Molecular; Excitation Contraction Coupling; Fishes; Genome; Muscle, Skeletal; Myocytes, Cardiac; Ryanodine Receptor Calcium Release Channel; Sarcoplasmic Reticulum
PubMed: 31646515
DOI: 10.1007/978-3-030-12457-1_12 -
Circulation Research Jul 2021
Topics: Death, Sudden, Cardiac; Gain of Function Mutation; Humans; Ryanodine Receptor Calcium Release Channel; Sarcoplasmic Reticulum
PubMed: 34292783
DOI: 10.1161/CIRCRESAHA.121.319651 -
Biomolecules Jul 2022The ryanodine receptor (RyR2) has a critical role in controlling Ca release from the sarcoplasmic reticulum (SR) throughout the cardiac cycle. RyR2 protein has multiple... (Review)
Review
The ryanodine receptor (RyR2) has a critical role in controlling Ca release from the sarcoplasmic reticulum (SR) throughout the cardiac cycle. RyR2 protein has multiple functional domains with specific roles, and four of these RyR2 protomers are required to form the quaternary structure that comprises the functional channel. Numerous mutations in the gene encoding RyR2 protein have been identified and many are linked to a wide spectrum of arrhythmic heart disease. Gain of function mutations (GoF) result in a hyperactive channel that causes excessive spontaneous SR Ca release. This is the predominant cause of the inherited syndrome catecholaminergic polymorphic ventricular tachycardia (CPVT). Recently, rare hypoactive loss of function (LoF) mutations have been identified that produce atypical effects on cardiac Ca handling that has been termed calcium release deficiency syndrome (CRDS). Aberrant Ca release resulting from both GoF and LoF mutations can result in arrhythmias through the Na/Ca exchange mechanism. This mini-review discusses recent findings regarding the role of RyR2 domains and endogenous regulators that influence RyR2 gating normally and with GoF/LoF mutations. The arrhythmogenic consequences of GoF/LoF mutations will then be discussed at the macromolecular and cellular level.
Topics: Arrhythmias, Cardiac; Calcium; Calcium Signaling; Humans; Mutation; Myocytes, Cardiac; Ryanodine Receptor Calcium Release Channel; Sarcoplasmic Reticulum
PubMed: 35892340
DOI: 10.3390/biom12081030 -
Trends in Biochemical Sciences Jun 2021Historically, ryanodine receptors (RyRs) have presented unique challenges for high-resolution structural determination despite long-standing interest in their role in... (Review)
Review
Historically, ryanodine receptors (RyRs) have presented unique challenges for high-resolution structural determination despite long-standing interest in their role in excitation-contraction coupling. Owing to their large size (nearly 2.2 MDa), high-resolution structures remained elusive until the advent of cryogenic electron microscopy (cryo-EM) techniques. In recent years, structures for both RyR1 and RyR2 have been solved at near-atomic resolution. Furthermore, recent reports have delved into their more complex structural associations with key modulators - proteins such as the dihydropyridine receptor (DHPR), FKBP12/12.6, and calmodulin (CaM), as well as ions and small molecules including Ca, ATP, caffeine, and PCB95. This review addresses the modulation of RyR1 and RyR2, in addition to the impact of such discoveries on intracellular Ca dynamics and biophysical properties.
Topics: Calcium; Calmodulin; Cryoelectron Microscopy; Microscopy, Electron; Ryanodine Receptor Calcium Release Channel
PubMed: 33353849
DOI: 10.1016/j.tibs.2020.11.009 -
Trends in Molecular Medicine Jan 2024Hippocampal synaptic plasticity is widely considered the cellular basis of learning and spatial memory processes. This article highlights the central role of Ca release... (Review)
Review
Hippocampal synaptic plasticity is widely considered the cellular basis of learning and spatial memory processes. This article highlights the central role of Ca release from the endoplasmic reticulum (ER) in hippocampal synaptic plasticity and hippocampus-dependent memory in health and disease. The key participation of ryanodine receptor (RyR) channels, which are the principal Ca release channels expressed in the hippocampus, in these processes is emphasized. It is proposed that the increased neuronal oxidative tone displayed by hippocampal neurons during aging or Alzheimer's disease (AD) leads to excessive activation of RyR-mediated Ca release, a process that is highly redox-sensitive, and that this abnormal response contributes to and aggravates these deleterious conditions.
Topics: Humans; Ryanodine Receptor Calcium Release Channel; Calcium; Calcium Signaling; Neuronal Plasticity; Hippocampus; Alzheimer Disease
PubMed: 37957056
DOI: 10.1016/j.molmed.2023.10.008 -
Frontiers in Cellular Neuroscience 2024Intracellular Ca-signaling in astrocytes is instrumental for their brain "housekeeping" role and astroglial control of synaptic plasticity. An important source for...
Intracellular Ca-signaling in astrocytes is instrumental for their brain "housekeeping" role and astroglial control of synaptic plasticity. An important source for elevating the cytosolic Ca level in astrocytes is a release from endoplasmic reticulum which can be triggered via two fundamental pathways: IP3 receptors and calcium-induced calcium release (CICR) mediated by Ca-sensitive ryanodine receptors (RyRs). While the physiological role for glial IP3 became a focus of intensive research and debate, ryanodine receptors received much less attention. We explored the role for ryanodine receptors in the modulation of cytosolic Ca-signaling in the cortical and hippocampal astrocytes, astrocyte-neuron communication and astroglia modulation of synaptic plasticity. Our data show that RyR-mediated Ca-induced Ca-release from ER brings substantial contribution into signaling in the functional microdomains hippocampal and neocortical astrocytes. Furthermore, RyR-mediated CICR activated the release of ATP and glutamate from hippocampal and neocortical astrocytes which, in turn, elicited transient purinergic and tonic glutamatergic currents in the neighboring pyramidal neurons. The CICR-facilitated release of ATP and glutamate was inhibited after intracellular perfusion of astrocytes with ryanodine and BAPTA and in the transgenic dnSNARE mice with impaired astroglial exocytosis. We also found out that RyR-mediated amplification of astrocytic Ca-signaling enhanced the long-term synaptic potentiation in the hippocampus and neocortex of aged mice. Combined, our data demonstrate that ryanodine receptors are essential for astrocytic Ca-signaling and efficient astrocyte-neuron communications. The RyR-mediated CICR contributes to astrocytic control of synaptic plasticity and can underlie, at least partially, neuroprotective and cognitive effects of caffein.
PubMed: 38812795
DOI: 10.3389/fncel.2024.1382010 -
ELife Feb 2023Activation of voltage-gated calcium channels at presynaptic terminals leads to local increases in calcium and the fusion of synaptic vesicles containing...
Activation of voltage-gated calcium channels at presynaptic terminals leads to local increases in calcium and the fusion of synaptic vesicles containing neurotransmitter. Presynaptic output is a function of the density of calcium channels, the dynamic properties of the channel, the distance to docked vesicles, and the release probability at the docking site. We demonstrate that at neuromuscular junctions two different classes of voltage-gated calcium channels, CaV2 and CaV1, mediate the release of distinct pools of synaptic vesicles. CaV2 channels are concentrated in densely packed clusters ~250 nm in diameter with the active zone proteins Neurexin, α-Liprin, SYDE, ELKS/CAST, RIM-BP, α-Catulin, and MAGI1. CaV2 channels are colocalized with the priming protein UNC-13L and mediate the fusion of vesicles docked within 33 nm of the dense projection. CaV2 activity is amplified by ryanodine receptor release of calcium from internal stores, triggering fusion up to 165 nm from the dense projection. By contrast, CaV1 channels are dispersed in the synaptic varicosity, and are colocalized with UNC-13S. CaV1 and ryanodine receptors are separated by just 40 nm, and vesicle fusion mediated by CaV1 is completely dependent on the ryanodine receptor. Distinct synaptic vesicle pools, released by different calcium channels, could be used to tune the speed, voltage-dependence, and quantal content of neurotransmitter release.
Topics: Animals; Caenorhabditis elegans; Calcium; Neurotransmitter Agents; Presynaptic Terminals; Ryanodine Receptor Calcium Release Channel; Synaptic Transmission; Synaptic Vesicles
PubMed: 36820519
DOI: 10.7554/eLife.81407 -
American Journal of Physiology. Heart... Oct 2023Ryanodine receptor 2 (RyR2) hyperactivity is observed in structural heart diseases that are a result of ischemia or heart failure. It causes abnormal calcium handling...
Ryanodine receptor 2 (RyR2) hyperactivity is observed in structural heart diseases that are a result of ischemia or heart failure. It causes abnormal calcium handling and calcium leaks that cause metabolic, electrical, and mechanical dysfunction, which can trigger arrhythmias. Here, we tested the antiarrhythmic potential of dantrolene (RyR inhibitor) in human hearts. Human hearts not used in transplantation were obtained, and right ventricular outflow tract (RVOT) wedges and left ventricular (LV) slices were prepared. Pseudo-ECGs were recorded to determine premature ventricular contraction (PVC) incidences. Optical mapping was performed to determine arrhythmogenic substrates. After baseline optical recordings, tissues were treated with ) isoproterenol (250 nM), ) caffeine (200 mM), and ) dantrolene (2 or 10 mM). Optical recordings were obtained after each treatment. Isoproterenol and caffeine treatment increased PVC incidence, whereas dantrolene reduced the PVC burden. Isoproterenol shortened action potential duration (APD) in the RV, RVOT, and LV regions and shortened calcium transient duration (CaTD) in the LV. Caffeine further shortened APD in the RV, did not modulate APD in the RVOT, and prolonged APD in the LV. In addition, in the LV, CaTD prolongation was also observed. More importantly, adding dantrolene did not alter APD in the RV or RVOT regions but produced a trend toward APD prolongation and significant CaTD prolongation in the LV, restoring these parameters to baseline values. In conclusions, dantrolene treatment suppresses triggers and reverses arrhythmogenic substrates in the human heart and could be a novel antiarrhythmic therapy in patients with structural heart disease. Ryanodine receptor 2 hyperactivity is observed in structural heart diseases caused by ischemia or heart failure. It causes abnormal calcium leaks, which can trigger arrhythmias. To prevent arrhythmias, we applied dantrolene in human hearts ex vivo. Isoproterenol and caffeine treatment increased PVC incidence, whereas dantrolene reduced the PVC burden. Dantrolene treatment suppresses triggers and reverses arrhythmogenic substrates and could be a novel antiarrhythmic therapy in patients with structural heart disease.
Topics: Humans; Ryanodine Receptor Calcium Release Channel; Dantrolene; Isoproterenol; Ryanodine; Calcium; Caffeine; Arrhythmias, Cardiac; Anti-Arrhythmia Agents; Heart Failure; Action Potentials
PubMed: 37566110
DOI: 10.1152/ajpheart.00103.2023 -
Journal of Cachexia, Sarcopenia and... Apr 2024Duchenne muscular dystrophy (DMD) is an X-linked disorder characterized by progressive muscle weakness due to the absence of functional dystrophin. DMD patients also...
BACKGROUND
Duchenne muscular dystrophy (DMD) is an X-linked disorder characterized by progressive muscle weakness due to the absence of functional dystrophin. DMD patients also develop dilated cardiomyopathy (DCM). We have previously shown that DMD (mdx) mice and a canine DMD model (GRMD) exhibit abnormal intracellular calcium (Ca) cycling related to early-stage pathological remodelling of the ryanodine receptor intracellular calcium release channel (RyR2) on the sarcoplasmic reticulum (SR) contributing to age-dependent DCM.
METHODS
Here, we used hiPSC-CMs from DMD patients selected by Speckle-tracking echocardiography and canine DMD cardiac biopsies to assess key early-stage Duchenne DCM features.
RESULTS
Dystrophin deficiency was associated with RyR2 remodelling and SR Ca leak (RyR2 Po of 0.03 ± 0.01 for HC vs. 0.16 ± 0.01 for DMD, P < 0.01), which led to early-stage defects including senescence. We observed higher levels of senescence markers including p15 (2.03 ± 0.75 for HC vs. 13.67 ± 5.49 for DMD, P < 0.05) and p16 (1.86 ± 0.83 for HC vs. 10.71 ± 3.00 for DMD, P < 0.01) in DMD hiPSC-CMs and in the canine DMD model. The fibrosis was increased in DMD hiPSC-CMs. We observed cardiac hypocontractility in DMD hiPSC-CMs. Stabilizing RyR2 pharmacologically by S107 prevented most of these pathological features, including the rescue of the contraction amplitude (1.65 ± 0.06 μm for DMD vs. 2.26 ± 0.08 μm for DMD + S107, P < 0.01). These data were confirmed by proteomic analyses, in particular ECM remodelling and fibrosis.
CONCLUSIONS
We identified key cellular damages that are established earlier than cardiac clinical pathology in DMD patients, with major perturbation of the cardiac ECC. Our results demonstrated that cardiac fibrosis and premature senescence are induced by RyR2 mediated SR Ca leak in DMD cardiomyocytes. We revealed that RyR2 is an early biomarker of DMD-associated cardiac damages in DMD patients. The progressive and later DCM onset could be linked with the RyR2-mediated increased fibrosis and premature senescence, eventually causing cell death and further cardiac fibrosis in a vicious cycle leading to further hypocontractility as a major feature of DCM. The present study provides a novel understanding of the pathophysiological mechanisms of the DMD-induced DCM. By targeting RyR2 channels, it provides a potential pharmacological treatment.
Topics: Humans; Mice; Animals; Dogs; Cardiomyopathy, Dilated; Dystrophin; Ryanodine Receptor Calcium Release Channel; Mice, Inbred mdx; Calcium; Proteomics; Myocytes, Cardiac; Cardiomyopathies; Fibrosis
PubMed: 38221511
DOI: 10.1002/jcsm.13411