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Ruan H, Wang T, Ren H, Zhang Y. AtFH5-labeled secretory vesicles-dependent calcium oscillation drives exocytosis and stepwise bulge during pollen germination. Cell Rep 2023; 42:113319. [PMID: 37897722 DOI: 10.1016/j.celrep.2023.113319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 09/11/2023] [Accepted: 10/06/2023] [Indexed: 10/30/2023] Open
Abstract
Pollen germination is an essential step for delivering sperm cells to the embryo sac for double fertilization in flowering plants. The cytosolic Ca2+ concentration ([Ca2+]cyt) and vesicle dynamics are critical for pollen germination, but their potential correlation in pollen grains is not fully understood. Here, we report that [Ca2+]cyt oscillates periodically at the prospective germination sites during pollen germination. The [Ca2+]cyt is mainly from extracellular Ca2+ ([Ca2+]ext) influx, which implicates the Ca2+-permeable ion channel cyclic nucleotide-gated channel 18 (CNGC18). The [Ca2+]cyt oscillations spatiotemporally correlate with the accumulation of secretory vesicles labeled by a formin protein AtFH5, and disruption of vesicle accumulation inhibits the [Ca2+]cyt oscillations. In turn, the [Ca2+]cyt oscillations promote exocytosis, which leads to stepwise cell extension during pollen germination. Together, these data provide a timeline of vesicle dynamics, calcium oscillation, and exocytosis during pollen germination and highlight the importance of the correlation of these events for pollen germination.
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Cabeza JP, Cámera J, Briski O, Felipe MY, Salamone DF, Gambini A. Preimplantation Developmental Competence of Bovine and Porcine Oocytes Activated by Zinc Chelation. Animals (Basel) 2022; 12:ani12243560. [PMID: 36552480 PMCID: PMC9774810 DOI: 10.3390/ani12243560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 12/12/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
After sperm-oocyte fusion, intracytoplasmic rises of calcium (Ca) induce the release of zinc (Zn) out of the oocyte (Zn sparks). Both phenomena are known to play an essential role in the oocyte activation process. Our work aimed to explore different protocols for activating bovine and porcine oocytes using the novel zinc chelator 1,10-phenanthroline (PHEN) and to compare developmental rates and quality to bovine IVF and parthenogenetic ionomycin-induced embryos in both species. Different incubation conditions for the zinc chelator were tested, including its combination with ionomycin. Embryo quality was assessed by immunofluorescence of SOX2, SOX17, OCT4, and CDX2 and total cell number at the blastocyst stage. Even though blastocyst development was achieved using a zinc chelator in bovine, bypassing calcium oscillations, developmental rates, and blastocyst quality were compromised compared to embryos generated with sperm-induced or ionomycin calcium rise. On the contrary, zinc chelation is sufficient to trigger oocyte activation in porcine. Additionally, we determined the optimal exposure to PHEN for this species. Zinc chelation and artificial induction of calcium rise combined did not improve developmental competence. Our results contribute to understanding the role of zinc during oocyte activation and preimplantation embryo development across different mammalian species.
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Sato K, Saito S, Endo K, Kono M, Kakei T, Taketa H, Kato M, Hamamoto S, Grenzi M, Costa A, Munemasa S, Murata Y, Ishimaru Y, Uozumi N. Green Tea Catechins, (-)-Catechin Gallate, and (-)-Gallocatechin Gallate are Potent Inhibitors of ABA-Induced Stomatal Closure. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2201403. [PMID: 35524639 PMCID: PMC9313475 DOI: 10.1002/advs.202201403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/06/2022] [Indexed: 06/04/2023]
Abstract
Stomatal movement is indispensable for plant growth and survival in response to environmental stimuli. Cytosolic Ca2+ elevation plays a crucial role in ABA-induced stomatal closure during drought stress; however, to what extent the Ca2+ movement across the plasma membrane from the apoplast to the cytosol contributes to this process still needs clarification. Here the authors identify (-)-catechin gallate (CG) and (-)-gallocatechin gallate (GCG), components of green tea, as inhibitors of voltage-dependent K+ channels which regulate K+ fluxes in Arabidopsis thaliana guard cells. In Arabidopsis guard cells CG/GCG prevent ABA-induced: i) membrane depolarization; ii) activation of Ca2+ permeable cation (ICa ) channels; and iii) cytosolic Ca2+ transients. In whole Arabidopsis plants co-treatment with CG/GCG and ABA suppressed ABA-induced stomatal closure and surface temperature increase. Similar to ABA, CG/GCG inhibited stomatal closure is elicited by the elicitor peptide, flg22 but has no impact on dark-induced stomatal closure or light- and fusicoccin-induced stomatal opening, suggesting that the inhibitory effect of CG/GCG is associated with Ca2+ -related signaling pathways. This study further supports the crucial role of ICa channels of the plasma membrane in ABA-induced stomatal closure. Moreover, CG and GCG represent a new tool for the study of abiotic or biotic stress-induced signal transduction pathways.
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Ying S, Scheible W. A novel calmodulin-interacting Domain of Unknown Function 506 protein represses root hair elongation in Arabidopsis. PLANT, CELL & ENVIRONMENT 2022; 45:1796-1812. [PMID: 35312071 PMCID: PMC9314033 DOI: 10.1111/pce.14316] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/13/2022] [Accepted: 02/22/2022] [Indexed: 06/14/2023]
Abstract
Domain of Unknown Function 506 proteins are ubiquitous in plants. The phosphorus (P) stress-inducible REPRESSOR OF EXCESSIVE ROOT HAIR GROWTH1 (AtRXR1) gene encodes the first characterized DUF506. AtRXR1 inhibits root hair elongation by interacting with RabD2c GTPase. However, functions of other P-responsive DUF506 genes are still missing. Here, we selected two additional P-inducible DUF506 genes for further investigation. The expression of both genes was induced by auxin. Under P-stress, At3g07350 gene expressed ubiquitously in seedlings, whereas At1g62420 (AtRXR3) expression was strongest in roots. AtRXR3 overexpressors and knockouts had shorter and longer root hairs, respectively. A functional AtRXR3-green fluorescent protein fusion localized to root epidermal cells. Chromatin immunoprecipitation and quantitative reverse-transcriptase-polymerase chain reaction revealed that AtRXR3 was transcriptionally activated by RSL4. Bimolecular fluorescence complementation and calmodulin (CaM)-binding assays showed that AtRXR3 interacted with CaM in the presence of Ca2+ . Moreover, cytosolic Ca2+ ([Ca2+ ]cyt ) oscillations in root hairs of rxr3 mutants exhibited elevated frequencies and dampened amplitudes compared to those of wild type. Thus, AtRXR3 is another DUF506 protein that attenuates P-limitation-induced root hair growth through mechanisms that involve RSL4 and interaction with CaM to modulate tip-focused [Ca2+ ]cyt oscillations.
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Chen H, Li P, Du X, Zhao Y, Wang L, Tian Y, Song X, Shuai L, Bai X, Chen L. Homozygous Loss of Septin12, but not its Haploinsufficiency, Leads to Male Infertility and Fertilization Failure. Front Cell Dev Biol 2022; 10:850052. [PMID: 35547809 PMCID: PMC9082362 DOI: 10.3389/fcell.2022.850052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 04/06/2022] [Indexed: 11/23/2022] Open
Abstract
The SEPTIN12 gene has been associated with male infertility. Male Septin12+/− chimera mice were infertile, supporting the prevailing view that SEPTIN12 haploinsufficiency causes male infertility. In this study, we identified a heterozygous mutation on SEPTIN12, c.72C>A (p.Cys24Ter) in the male partner of a patient couple, who had a previous fertilization failure (FF) after intracytoplasmic sperm injection (ICSI) and became pregnant after ICSI together with artificial oocyte activation (AOA). To investigate the role of SEPTIN12 in FF and oocyte activation, we constructed Septin12 knockout mice. Surprisingly, Septin12−/− male mice, but not Septin12+/− male mice, are infertile, and have reduced sperm counts and abnormal sperm morphology. Importantly, AOA treatment enhances the 2-cell embryo rate of ICSI embryos injected with Septin12−/− sperm, indicating that FF caused by male Septin12 deficiency is overcome by AOA. Mechanistically, loss of PLCζ around the acrosome might be the reason for FF of Septin12−/− sperm. Taken together, our data indicated that homozygous knockout of Septin12, but not Septin12 haploinsufficiency, leads to male infertility and FF.
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Finely-Tuned Calcium Oscillations in Osteoclast Differentiation and Bone Resorption. Int J Mol Sci 2020; 22:ijms22010180. [PMID: 33375370 PMCID: PMC7794828 DOI: 10.3390/ijms22010180] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 12/27/2022] Open
Abstract
Calcium (Ca2+) plays an important role in regulating the differentiation and function of osteoclasts. Calcium oscillations (Ca oscillations) are well-known phenomena in receptor activator of nuclear factor kappa B ligand (RANKL)-induced osteoclastogenesis and bone resorption via calcineurin. Many modifiers are involved in the fine-tuning of Ca oscillations in osteoclasts. In addition to macrophage colony-stimulating factors (M-CSF; CSF-1) and RANKL, costimulatory signaling by immunoreceptor tyrosine-based activation motif-harboring adaptors is important for Ca oscillation generation and osteoclast differentiation. DNAX-activating protein of 12 kD is always necessary for osteoclastogenesis. In contrast, Fc receptor gamma (FcRγ) works as a key controller of osteoclastogenesis especially in inflammatory situation. FcRγ has a cofactor in fine-tuning of Ca oscillations. Some calcium channels and transporters are also necessary for Ca oscillations. Transient receptor potential (TRP) channels are well-known environmental sensors, and TRP vanilloid channels play an important role in osteoclastogenesis. Lysosomes, mitochondria, and endoplasmic reticulum (ER) are typical organelles for intracellular Ca2+ storage. Ryanodine receptor, inositol trisphosphate receptor, and sarco/endoplasmic reticulum Ca2+ ATPase on the ER modulate Ca oscillations. Research on Ca oscillations in osteoclasts has still many problems. Surprisingly, there is no objective definition of Ca oscillations. Causality between Ca oscillations and osteoclast differentiation and/or function remains to be examined.
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Persistent Activity of Metabotropic Glutamate Receptor 5 in the Periaqueductal Gray Constrains Emergence of Chronic Neuropathic Pain. Curr Biol 2020; 30:4631-4642.e6. [PMID: 32976802 DOI: 10.1016/j.cub.2020.09.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 07/15/2020] [Accepted: 09/03/2020] [Indexed: 12/13/2022]
Abstract
Pain sensation is powerfully modulated by signal processing in the brain, and pain becomes chronic with the dysfunction of the pain modulatory system; however, the underlying mechanisms are unclear. We found that the metabotropic glutamate receptor 5 (mGluR5) in the periaqueductal gray (PAG), the key area of endogenous pain modulation, is persistently active in normal conditions to maintain an appropriate sensory perception. In the neuropathic pain condition, Homer1a, an activity-dependent immediate early gene product, disrupted the persistent mGluR5 activity resulting in chronic pain. Remarkably a single-time blockage of the mGluR5 resulted in chronic neuropathic pain-like symptoms even in the absence of nerve injury. The decline of mGluR5 activity induced the pain modulatory dysfunction with a profound reduction of excitability of PAG neurons. These findings uncover the role of the persistent mGluR5 activity in vivo and provide new insight into how pain becomes chronic with the maladaptive coping of the PAG to pain sensation.
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Kim D, Choe HK, Kim K. Ultradian Rhythms in the Hypothalamic Arcuate Nucleus Kisspeptin Neurons and Developmental Processes. Mol Cells 2020; 43:600-606. [PMID: 32489185 PMCID: PMC7398798 DOI: 10.14348/molcells.2020.0066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/22/2020] [Accepted: 05/11/2020] [Indexed: 11/27/2022] Open
Abstract
Numerous physiological processes in nature have multiple oscillations within 24 h, that is, ultradian rhythms. Compared to the circadian rhythm, which has a period of approximately one day, these short oscillations range from seconds to hours, and the mechanisms underlying ultradian rhythms remain largely unknown. This review aims to explore and emphasize the implications of ultradian rhythms and their underlying regulations. Reproduction and developmental processes show ultradian rhythms, and these physiological systems can be regulated by short biological rhythms. Specifically, we recently uncovered synchronized calcium oscillations in the organotypic culture of hypothalamic arcuate nucleus (ARN) kisspeptin neurons that regulate reproduction. Synchronized calcium oscillations were dependent on voltage-gated ion channel-mediated action potentials and were repressed by chemogenetic inhibition, suggesting that the network within the ARN and between the kisspeptin population mediates the oscillation. This minireview describes that ultradian rhythms are a general theme that underlies biological features, with special reference to calcium oscillations in the hypothalamic ARN from a developmental perspective. We expect that more attention to these oscillations might provide insight into physiological or developmental mechanisms, since many oscillatory features in nature still remain to be explored.
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Liu J, McDaid L, Araque A, Wade J, Harkin J, Karim S, Henshall DC, Connolly NMC, Johnson AP, Tyrrell AM, Timmis J, Millard AG, Hilder J, Halliday DM. GABA Regulation of Burst Firing in Hippocampal Astrocyte Neural Circuit: A Biophysical Model. Front Cell Neurosci 2019; 13:335. [PMID: 31396055 PMCID: PMC6664076 DOI: 10.3389/fncel.2019.00335] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Accepted: 07/08/2019] [Indexed: 12/30/2022] Open
Abstract
It is now widely accepted that glia cells and gamma-aminobutyric acidergic (GABA) interneurons dynamically regulate synaptic transmission and neuronal activity in time and space. This paper presents a biophysical model that captures the interaction between an astrocyte cell, a GABA interneuron and pre/postsynaptic neurons. Specifically, GABA released from a GABA interneuron triggers in astrocytes the release of calcium (Ca2+) from the endoplasmic reticulum via the inositol 1, 4, 5-trisphosphate (IP3) pathway. This results in gliotransmission which elevates the presynaptic transmission probability rate (PR) causing weight potentiation and a gradual increase in postsynaptic neuronal firing, that eventually stabilizes. However, by capturing the complex interactions between IP3, generated from both GABA and the 2-arachidonyl glycerol (2-AG) pathway, and PR, this paper shows that this interaction not only gives rise to an initial weight potentiation phase but also this phase is followed by postsynaptic bursting behavior. Moreover, the model will show that there is a presynaptic frequency range over which burst firing can occur. The proposed model offers a novel cellular level mechanism that may underpin both seizure-like activity and neuronal synchrony across different brain regions.
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Liu HN, Hirata H, Okuno Y, Okabe M, Furukawa K. Dopamine and Serotonin Receptors Cooperatively Modulate Pacemaker Activity of Intestinal Cells of Cajal. CHINESE J PHYSIOL 2018; 61:302-312. [PMID: 30384551 DOI: 10.4077/cjp.2018.bah607] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The neurotransmitters dopamine and serotonin control the peristaltic movement of the gut
that consists of propagating waves of rhythmic contraction and relaxation. While intestinal cells of
Cajal (ICC) serve as a pacemaker in the gut, the effect of dopamine on the pacemaker activity of ICC
remains unknown. Here, we report that together with serotonin receptors, the dopamine receptor D₂
contributes to maintaining [Ca²⁺]i oscillations in ileum ICC. When the antagonist for the D₂ receptor
was applied to the cell cluster or the tissue culture prepared from muscle layers of the mouse small
intestine, the amplitude of [Ca²⁺]i oscillations in ICC declined after a transient increase. On the other
hand, treatment with the D₂ receptor agonist decreased the frequency of [Ca²⁺]i oscillations in ICC.
These results suggest that basal level activity of the D₂ receptor is crucial for maintaining [Ca²⁺]i
oscillations in ICC. The decrease in the [Ca²⁺]i oscillation amplitude upon the D₂ receptor antagonist
treatment was abrogated by antagonizing the serotonin receptor 5HT₂, indicating an inhibitory effect
of the 5HT₂ receptor on the [Ca²⁺]i oscillations. Together with the finding that treatment with the
antagonist for the serotonin receptor 5HT₃ completely eliminated [Ca²⁺]i oscillations in ICC, our
results show that dopamine and serotonin receptors cooperatively regulate pacemaker activity of
ICC.
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Guo F, Holla M, Díaz MM, Rosbash M. A Circadian Output Circuit Controls Sleep-Wake Arousal in Drosophila. Neuron 2018; 100:624-635.e4. [PMID: 30269992 DOI: 10.1016/j.neuron.2018.09.002] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 07/05/2018] [Accepted: 08/31/2018] [Indexed: 10/28/2022]
Abstract
The Drosophila core circadian circuit contains distinct groups of interacting neurons that give rise to diurnal sleep-wake patterns. Previous work showed that a subset of dorsal neurons 1 (DN1s) are sleep-promoting through their inhibition of activity-promoting circadian pacemakers. Here we show that these anterior-projecting DNs (APDNs) also "exit" the circadian circuitry and communicate with the homeostatic sleep center in higher brain regions to regulate sleep and sleep-wake arousal. These APDNs connect to a small, discrete subset of tubercular-bulbar neurons, which are connected in turn to specific sleep-centric ellipsoid body (EB)-ring neurons of the central complex. Remarkably, activation of the APDNs produces sleep-like oscillations in the EB and affects arousal. The data indicate that this APDN-TuBusup-EB circuit temporally regulates sleep-wake arousal in addition to the previously defined role of the TuBu-EB circuit in vision, navigation, and attention.
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Abstract
The transmembrane docking of endoplasmic reticulum (ER) Ca2+-sensing STIM proteins with plasma membrane (PM) Orai Ca2+ channels is a critical but poorly understood step in Ca2+ signal generation. STIM1 protein dimers unfold to expose a discrete STIM-Orai activating region (SOAR1) that tethers and activates Orai1 channels within discrete ER-PM junctions. We reveal that each monomer within the SOAR dimer interacts independently with single Orai1 subunits to mediate cross-linking between Orai1 channels. Superresolution imaging and mobility measured by fluorescence recovery after photobleaching reveal that SOAR dimer cross-linking leads to substantial Orai1 channel clustering, resulting in increased efficacy and cooperativity of Orai1 channel function. A concatenated SOAR1 heterodimer containing one monomer point mutated at its critical Orai1 binding residue (F394H), although fully activating Orai channels, is completely defective in cross-linking Orai1 channels. Importantly, the naturally occurring STIM2 variant, STIM2.1, has an eight-amino acid insert in its SOAR unit that renders it functionally identical to the F394H mutant in SOAR1. Contrary to earlier predictions, the SOAR1-SOAR2.1 heterodimer fully activates Orai1 channels but prevents cross-linking and clustering of channels. Interestingly, combined expression of full-length STIM1 with STIM2.1 in a 5:1 ratio causes suppression of sustained agonist-induced Ca2+ oscillations and protects cells from Ca2+ overload, resulting from high agonist-induced Ca2+ release. Thus, STIM2.1 exerts a powerful regulatory effect on signal generation likely through preventing Orai1 channel cross-linking. Overall, STIM-mediated cross-linking of Orai1 channels is a hitherto unrecognized functional paradigm that likely provides an organizational microenvironment within ER-PM junctions with important functional impact on Ca2+ signal generation.
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Ujita S, Sasaki T, Asada A, Funayama K, Gao M, Mikoshiba K, Matsuki N, Ikegaya Y. cAMP-Dependent Calcium Oscillations of Astrocytes: An Implication for Pathology. Cereb Cortex 2018; 27:1602-1614. [PMID: 26803165 DOI: 10.1093/cercor/bhv310] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Astrocytes in various brain regions exhibit spontaneous intracellular calcium elevations both in vitro and in vivo; however, neither the temporal pattern underlying this activity nor its function has been fully evaluated. Here, we utilized a long-term optical imaging technique to analyze the calcium activity of more than 4000 astrocytes in acute hippocampal slices as well as in the neocortex and hippocampus of head-restrained mice. Although astrocytic calcium activity was largely sparse and irregular, we observed a subset of cells in which the fluctuating calcium oscillations repeated at a regular interval of ∼30 s. These intermittent oscillations i) depended on type 2 inositol 1,4,5-trisphosphate receptors; ii) consisted of a complex reverberatory interaction between the soma and processes of individual astrocytes; iii) did not synchronize with those of other astrocytes; iv) did not require neuronal firing; v) were modulated through cAMP-protein kinase A signaling; vi) were facilitated under pathological conditions, such as energy deprivation and epileptiform hyperexcitation; and vii) were associated with enhanced hypertrophy in astrocytic processes, an early hallmark of reactive gliosis, which is observed in ischemia and epilepsy. Therefore, calcium oscillations appear to be associated with a pathological state in astrocytes.
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Xu YR, Yang WX. Calcium influx and sperm-evoked calcium responses during oocyte maturation and egg activation. Oncotarget 2017; 8:89375-89390. [PMID: 29179526 PMCID: PMC5687696 DOI: 10.18632/oncotarget.19679] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 06/19/2017] [Indexed: 12/18/2022] Open
Abstract
Under the guidance and regulation of hormone signaling, large majority of mammalian oocytes go through twice cell cycle arrest-resumption prior to the fertilized egg splits: oocyte maturation and egg activation. Cytosolic free calcium elevations and endoplasmic reticulum calcium store alternations are actively involved in triggering the complex machineries and events during oogenesis. Among these, calcium influx had been implicated in the replenishment of endoplasmic reticulum store during oocyte maturation and calcium oscillation during egg activation. This process also drove successful fertilization and early embryo development. Store-operated Ca2+ entry, acts as the principal force of calcium influx, is composed of STIM1 and Orai1 on the plasma membrane. Besides, transient receptor potential channels also participate in the process of calcium inwards. In this review, we summarize the recent researches on the spatial-temporal distribution of store-operated calcium entry components and transient receptor potential channels. Questions about how these channels play function for calcium influx and what impacts these channels have on oocytes are discussed. At the time of sperm-egg fusion, sperm-specific factor(s) diffuse and enable eggs to mount intracellular calcium oscillations. In this review, we also focus on the basic knowledge and the modes of action of the potential sperm factor phospholipase C zeta, as well as the downstream receptor, type 1 inositol 1,4,5-trisphosphate receptor. From the achievement in the previous several decades, it is easy to find that there are too many doubtful points in the field that need researchers take into consideration and take action in the future.
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Zhou LH, Liu SB, Wang PF, Lu TJ, Xu F, Genin GM, Pickard BG. The Arabidopsis trichome is an active mechanosensory switch. PLANT, CELL & ENVIRONMENT 2017; 40:611-621. [PMID: 26920667 DOI: 10.1111/pce.12728] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 01/15/2016] [Accepted: 01/18/2016] [Indexed: 05/18/2023]
Abstract
Trichomes ('hair cells') on Arabidopsis thaliana stem and leaf surfaces provide a range of benefits arising from their shape and disposition. These include tempting herbivores to sample constitutive toxins before they reach the bulk of the tissue. We asked whether, in addition, small mechanical disturbances such as an insect can make elicit signals that might help the plant respond to herbivory. We imaged, pressed and brushed trichomes in several ways, most notably with confocal microscopy of trichomes transgenically provided with apoplastic pH reporter apo-pHusion and cytosolic Ca2+ reporter cameleon. In parallel, we modelled trichome wall mechanics with finite element analysis. The stimulated trichome focuses force on a pliant zone and the adjoining podium of the stalk. A buckling instability can further focus force on a skirt of cells surrounding the podium, eliciting oscillations of cytosolic Ca2+ and shifts in apoplastic pH. These observations represent active physiological response. Modelling establishes that the effectiveness of force focusing and buckling is due to the peculiar tapering wall structure of the trichome. Hypothetically, these active mechanosensing functions enhance toxin synthesis above constitutive levels, probably via a priming process, thus minimizing the costly accumulation of toxins in the absence of herbivore attack but assuring rapid build-up when needed.
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Jiang HN, Li Y, Cui ZJ. Photodynamic Physiology-Photonanomanipulations in Cellular Physiology with Protein Photosensitizers. Front Physiol 2017; 8:191. [PMID: 28421000 PMCID: PMC5378799 DOI: 10.3389/fphys.2017.00191] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 03/14/2017] [Indexed: 02/05/2023] Open
Abstract
Singlet oxygen generated in a type II photodynamic action, due to its limited lifetime (1 μs) and reactive distance (<10 nm), could regulate live cell function nanoscopically. The genetically-encoded protein photosensitizers (engineered fluorescent proteins such as KillerRed, TagRFP, and flavin-binding proteins such as miniSOG, Pp2FbFPL30M) could be expressed in a cell type- and/or subcellular organelle-specific manner for targeted protein photo-oxidative activation/desensitization. The newly emerged active illumination technique provides an additional level of specificity. Typical examples of photodynamic activation include permanent activation of G protein-coupled receptor CCK1 and photodynamic activation of ionic channel TRPA1. Protein photosensitizers have been used to photodynamically modulate major cellular functions (such as neurotransmitter release and gene transcription) and animal behavior. Protein photosensitizers are increasingly used in photon-driven nanomanipulation in cell physiology research.
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Mizutani H, Yamamura H, Muramatsu M, Hagihara Y, Suzuki Y, Imaizumi Y. Modulation of Ca2+ oscillation and melatonin secretion by BKCa channel activity in rat pinealocytes. Am J Physiol Cell Physiol 2016; 310:C740-7. [PMID: 26791489 DOI: 10.1152/ajpcell.00342.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 01/15/2016] [Indexed: 11/22/2022]
Abstract
The pineal glands regulate circadian rhythm through the synthesis and secretion of melatonin. The stimulation of nicotinic acetylcholine receptor due to parasympathetic nerve activity causes an increase in intracellular Ca(2+) concentration and eventually downregulates melatonin production. Our previous report shows that rat pinealocytes have spontaneous and nicotine-induced Ca(2+) oscillations that are evoked by membrane depolarization followed by Ca(2+) influx through voltage-dependent Ca(2+) channels (VDCCs). These Ca(2+) oscillations are supposed to contribute to the inhibitory mechanism of melatonin secretion. Here we examined the involvement of large-conductance Ca(2+)-activated K(+) (BKCa) channel conductance on the regulation of Ca(2+) oscillation and melatonin production in rat pinealocytes. Spontaneous Ca(2+) oscillations were markedly enhanced by BKCa channel blockers (1 μM paxilline or 100 nM iberiotoxin). Nicotine (100 μM)-induced Ca(2+) oscillations were also augmented by paxilline. In contrast, spontaneous Ca(2+) oscillations were abolished by BKCa channel opener [3 μM 12,14-dichlorodehydroabietic acid (diCl-DHAA)]. Under whole cell voltage-clamp configurations, depolarization-elicited outward currents were significantly activated by diCl-DHAA and blocked by paxilline. Expression analyses revealed that the α and β3 subunits of BKCa channel were highly expressed in rat pinealocytes. Importantly, the activity of BKCa channels modulated melatonin secretion from whole pineal gland of the rat. Taken together, BKCa channel activation attenuates these Ca(2+) oscillations due to depolarization-synchronized Ca(2+) influx through VDCCs and results in a recovery of reduced melatonin secretion during parasympathetic nerve activity. BKCa channels may play a physiological role for melatonin production via a negative-feedback mechanism.
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Yang PC, Jafri MS. The Phase Lag between Agonist-Induced Oscillatory Ca 2+ and IP 3 Signals Does Not Imply Causality (December 2015). CALCIUM SIGNALING (SANTA CLARA, CALIF.) 2015; 2:1-10. [PMID: 27218121 PMCID: PMC4874533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Activated phospholipase C (PLC*) generates 1,4,5-triphosphate (IP3) and diacylglycerol (DAG) from phosphatidyl inositol (PIP2). The DAG remains in the plasma membrane and co-activates conventional protein kinase C (PKC) with Ca2+. We have developed a mathematical model for the activation of the Ca2+-dependent PKC and its negative feedback on phospholipase C (PLC) and coupled it to the De Young-Keizer model for IP3 mediated Ca2+ oscillations. The model describes the cascade of reactions for the translocation of PKC to plasma membrane, and simulates activation of Ca2+ and diacylglycerol (DAG) oscillations. The model demonstrates that oscillations in Ca2+ and DAG are possible with or without a positive Ca2+ feedback on phospholipase C consistent with experiment. In many experimental studies, the timing of the peaks of the Ca2+ and IP3 oscillations have been used to suggest causality, i.e. that the IP3 oscillations cause the Ca2+ oscillations. The model is used to explore this question. To this end, the positive and negative feedback between Ca2+ and IP3 production are modulated, resulting in changes to the phase lag between the peaks in [Ca2+]cyt and [IP]cyt. The model simulates a possible experimental protocol that can be used to differentiate whether or not the positive feedback of Ca2+ on PLC is needed for the oscillations.
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Mizutani H, Yamamura H, Muramatsu M, Kiyota K, Nishimura K, Suzuki Y, Ohya S, Imaizumi Y. Spontaneous and nicotine-induced Ca2+ oscillations mediated by Ca2+ influx in rat pinealocytes. Am J Physiol Cell Physiol 2014; 306:C1008-16. [PMID: 24696145 DOI: 10.1152/ajpcell.00014.2014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The pineal gland regulates circadian rhythm through the synthesis and secretion of melatonin. The rise of intracellular Ca(2+) concentration ([Ca(2+)]i) following nicotinic acetylcholine receptor (nAChR) stimulation due to parasympathetic nerve activity downregulates melatonin production. Important characteristics and roles of Ca(2+) mobilization due to nAChR stimulation remain to be clarified. We report here that spontaneous Ca(2+) oscillations can be observed in ∼15% of the pinealocytes in slice preparations from rat pineal glands when this dissociation procedure is done within 6 h from a dark-to-light change. The frequency and half-life of [Ca(2+)]i rise were 0.86 min(-1) and 19 s, respectively. Similar spontaneous Ca(2+) oscillations were recorded in 17% of rat pinealocytes that were primary cultured for several days. Simultaneous measurement of [Ca(2+)]i and membrane potential revealed that spontaneous Ca(2+) oscillations were triggered by periodic membrane depolarizations. Spontaneous Ca(2+) oscillations in cultured pinealocytes were abolished by extracellular Ca(2+) removal or application of nifedipine, a blocker of voltage-dependent Ca(2+) channel (VDCC). In contrast, blockers of intracellular Ca(2+)-release channels, 2-aminoethoxydiphenylborate and ryanodine, have no effect. Our results also reveal that, in 23% quiescent pinealocytes, Ca(2+) oscillations were observed following the withdrawal of nicotine. Norepinephrine-induced melatonin secretion from whole pineal glands was significantly decreased by the coapplication of acetylcholine (ACh). This inhibitory effect of ACh was attenuated by nifedipine. In conclusion, both spontaneous and evoked Ca(2+) oscillations are due to membrane depolarization following activation of VDCCs. This consists of VDCC α1F subunit, and the associated Ca(2+) influx can strongly regulate melatonin secretion in pineal glands.
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Kemény LV, Schnúr A, Czepán M, Rakonczay Z, Gál E, Lonovics J, Lázár G, Simonka Z, Venglovecz V, Maléth J, Judák L, Németh IB, Szabó K, Almássy J, Virág L, Geisz A, Tiszlavicz L, Yule DI, Wittmann T, Varró A, Hegyi P. Na+/Ca2+ exchangers regulate the migration and proliferation of human gastric myofibroblasts. Am J Physiol Gastrointest Liver Physiol 2013; 305:G552-63. [PMID: 23907822 DOI: 10.1152/ajpgi.00394.2012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Gastrointestinal myofibroblasts are contractile, electrically nonexcitable, transitional cells that play a role in extracellular matrix production, in ulcer healing, and in pathophysiological conditions they contribute to chronic inflammation and tumor development. Na+/Ca2+ exchangers (NCX) are known to have a crucial role in Ca2+ homeostasis of contractile cells, however, no information is available concerning the role of NCX in the proliferation and migration of gastrointestinal myofibroblasts. In this study, our aim was to investigate the role of NCX in the Ca2+ homeostasis, migration, and proliferation of human gastrointestinal myofibroblasts, focusing on human gastric myofibroblasts (HGMs). We used microfluorometric measurements to investigate the intracellular Ca2+ and Na+ concentrations, PCR analysis and immunostaining to show the presence of the NCX, patch clamp for measuring NCX activity, and proliferation and migration assays to investigate the functional role of the exchanger. We showed that 53.0±8.1% of the HGMs present Ca2+ oscillations, which depend on extracellular Ca2+ and Na+, and can be inhibited by NCX inhibitors. NCX1, NCX2, and NCX3 were expressed at both mRNA and protein levels in HGMs, and they contribute to the intracellular Ca2+ and Na+ homeostasis as well, regardless of the oscillatory activity. NCX inhibitors significantly blocked the basal and insulin-like growth factor II-stimulated migration and proliferation rates of HGMs. In conclusion, we showed that NCX plays a pivotal role in regulating the Ca2+ homeostasis, migration, and proliferation of HGMs. The inhibition of NCX activity may be a potential therapeutic target in hyperproliferative gastric diseases.
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Takahashi T, Igarashi H, Amita M, Hara S, Matsuo K, Kurachi H. Molecular mechanism of poor embryo development in postovulatory aged oocytes: mini review. J Obstet Gynaecol Res 2013; 39:1431-9. [PMID: 23876057 DOI: 10.1111/jog.12111] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2013] [Accepted: 02/27/2013] [Indexed: 11/29/2022]
Abstract
Oocyte quality is a key factor in determining embryo development; however, we have a poor understanding of what constitutes oocyte quality or the mechanisms governing it. Postovulatory aging of oocytes that have not been fertilized for a prolonged time after ovulation is known to significantly impair oocyte quality and subsequent embryo development after fertilization. Embryos derived from postovulatory-aged oocytes are prone to undergo apoptosis due to the decreased Bcl-2 expression. Postovulatory aging of oocytes changes the patterns of Ca(2+) oscillations at fertilization as a result of impaired Ca(2+) regulation in the endoplasmic reticulum. Moreover, postovulatory aging of oocytes impairs mitochondrial adenosine triphosphate production as a result of increasing oxidative stresses. Oxidative stresses also affect intracellular Ca(2+) regulation and impair embryo development after fertilization. Collectively, the mechanism of postovulatory oocyte aging might be involved in reactive oxygen species-induced mitochondrial injury followed by abnormal intracellular Ca(2+) regulation in the endoplasmic reticulum.
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Chen J, Wang Y, Wang Y, Yi X, Ge R. Studies on the effect of adenosine on calcium oscillation in hippocampal neurons. Exp Ther Med 2013; 5:1165-1168. [PMID: 23596485 PMCID: PMC3627451 DOI: 10.3892/etm.2013.973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Accepted: 02/13/2013] [Indexed: 11/05/2022] Open
Abstract
Adenosine (Ade) is an antiepileptic agent. In order to investigate the possible mechanism of action of Ade, its effect on calcium (Ca2+) oscillations in hippocampal neurons of Sprague Dawley (SD) rats was explored. Primary hippocampal neurons were cultured from suckling neonatal SD rats. Cells were cultured for 7–9 days and the Ca2+ oscillations in response to perfusion with Ade were detected using confocal laser scanning microscopy in combination with Fluo-3/AM labeling. This study found that Ade inhibits the spontaneous synchronized Ca2+ oscillation frequency and amplitude in mature hippocampal neurons and such inhibition depends on the Ade dosage level to a certain extent. Ade also had a significant inhibitory effect on high potassium-induced Ca2+ oscillation frequency and amplitude. Ade had a significant inhibitory effect on high-voltage-activated Ca2+ channel-mediated Ca2+ influx and Ca2+ oscillations in neurons. This may be one of the mechanisms for Ade to exert antiepileptic effects as an endogenous substance.
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Wang H, Westin L, Nong Y, Birnbaum S, Bendor J, Brismar H, Nestler E, Aperia A, Flajolet M, Greengard P. Norbin is an endogenous regulator of metabotropic glutamate receptor 5 signaling. Science 2010; 326:1554-7. [PMID: 20007903 DOI: 10.1126/science.1178496] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Metabotropic glutamate receptor 5 (mGluR5) is highly expressed in the mammalian central nervous system (CNS). It is involved in multiple physiological functions and is a target for treatment of various CNS disorders, including schizophrenia. We report that Norbin, a neuron-specific protein, physically interacts with mGluR5 in vivo, increases the cell surface localization of the receptor, and positively regulates mGluR5 signaling. Genetic deletion of Norbin attenuates mGluR5-dependent stable changes in synaptic function measured as long-term depression or long-term potentiation of synaptic transmission in the hippocampus. As with mGluR5 knockout mice or mice treated with mGluR5-selective antagonists, Norbin knockout mice showed a behavioral phenotype associated with a rodent model of schizophrenia, as indexed by alterations both in sensorimotor gating and psychotomimetic-induced locomotor activity.
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Kochukov MY, Jeng YJ, Watson CS. Alkylphenol xenoestrogens with varying carbon chain lengths differentially and potently activate signaling and functional responses in GH3/B6/F10 somatomammotropes. ENVIRONMENTAL HEALTH PERSPECTIVES 2009; 117:723-30. [PMID: 19479013 PMCID: PMC2685833 DOI: 10.1289/ehp.0800182] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Accepted: 12/31/2008] [Indexed: 05/02/2023]
Abstract
BACKGROUND Alkylphenols varying in their side-chain lengths [ethyl-, propyl-, octyl-, and nonylphenol (EP, PP, OP, and NP, respectively)] and bisphenol A (BPA) represent a large group of structurally related xenoestrogens that have endocrine-disruptive effects. Their rapid nongenomic effects that depend on structure for cell signaling and resulting functions are unknown. OBJECTIVES We compared nongenomic estrogenic activities of alkylphenols with BPA and 17beta-estradiol (E(2)) in membrane estrogen receptor-alpha-enriched GH3/B6/F10 pituitary tumor cells. These actions included calcium (Ca) signaling, prolactin (PRL) release, extracellular-regulated kinase (ERK) phosphorylation, and cell proliferation. METHODS We imaged Ca using fura-2, measured PRL release via radioimmunoassay, detected ERK phosphorylation by fixed cell immunoassay, and estimated cell number using the crystal violet assay. RESULTS All compounds caused increases in Ca oscillation frequency and intracellular Ca volume at 100 fM to 1 nM concentrations, although long-chain alkylphenols were most effective. All estrogens caused rapid PRL release at concentrations as low as 1 fM to 10 pM; the potency of EP, PP, and NP exceeded that of E(2). All compounds at 1 nM produced similar increases in ERK phosphorylation, causing rapid peaks at 2.5-5 min, followed by inactivation and additional 60-min peaks (except for BPA). Dose-response patterns of ERK activation at 5 min were similar for E2, BPA, and PP, whereas EP caused larger effects. Only E2 and NP increased cell number. Some rapid estrogenic responses showed correlations with the hydrophobicity of estrogenic molecules; the more hydrophobic OP and NP were superior at Ca and cell proliferation responses, whereas the less hydrophobic EP and PP were better at ERK activations. CONCLUSIONS Alkylphenols are potent estrogens in evoking these nongenomic responses contributing to complex functions; their hydrophobicity can largely predict these behaviors.
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Heart E, Yaney G, Corkey R, Schultz V, Luc E, Liu L, Deeney J, Shirihai O, Tornheim K, Smith P, Corkey B. Ca2+, NAD(P)H and membrane potential changes in pancreatic beta-cells by methyl succinate: comparison with glucose. Biochem J 2007; 403:197-205. [PMID: 17181533 PMCID: PMC1828901 DOI: 10.1042/bj20061209] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2006] [Revised: 12/14/2006] [Accepted: 12/20/2006] [Indexed: 11/17/2022]
Abstract
The present study was undertaken to determine the main metabolic secretory signals generated by the mitochondrial substrate MeS (methyl succinate) compared with glucose in mouse and rat islets and to understand the differences. Glycolysis and mitochondrial metabolism both have key roles in the stimulation of insulin secretion by glucose. Both fuels elicited comparable oscillatory patterns of Ca2+ and changes in plasma and mitochondrial membrane potential in rat islet cells and clonal pancreatic beta-cells (INS-1). Saturation of the Ca2+ signal occurred between 5 and 6 mM MeS, while secretion reached its maximum at 15 mM, suggesting operation of a K(ATP)-channel-independent pathway. Additional responses to MeS and glucose included elevated NAD(P)H autofluorescence in INS-1 cells and islets and increases in assayed NADH and NADPH and the ATP/ADP ratio. Increased NADPH and ATP/ADP ratios occurred more rapidly with MeS, although similar levels were reached after 5 min of exposure to each fuel, whereas NADH increased more with MeS than with glucose. Reversal of MeS-induced cell depolarization by Methylene Blue completely inhibited MeS-stimulated secretion, whereas basal secretion and KCl-induced changes in these parameters were not affected. MeS had no effect on secretion or signals in the mouse islets, in contrast with glucose, possibly due to a lack of malic enzyme. The data are consistent with the common intermediates being pyruvate, cytosolic NADPH or both, and suggest that cytosolic NADPH production could account for the more rapid onset of MeS-induced secretion compared with glucose stimulation.
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