scholarly journals Osmolarity-regulated swelling initiates egg activation in Drosophila

Open Biology ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 210067
Author(s):  
Anna H. York-Andersen ◽  
Benjamin W. Wood ◽  
Elise L. Wilby ◽  
Alexander S. Berry ◽  
Timothy T. Weil
Keyword(s):  
Transient Receptor Potential ◽  
Ex Vivo ◽  
Receptor Potential ◽  
Mature Oocyte ◽  
Posterior Pole ◽  
Vitelline Membrane ◽  
Egg Activation ◽  
Calcium Wave ◽  
M Channels ◽  
Transient Receptor

Egg activation is a series of highly coordinated processes that prepare the mature oocyte for embryogenesis. Typically associated with fertilization, egg activation results in many downstream outcomes, including the resumption of the meiotic cell cycle, translation of maternal mRNAs and cross-linking of the vitelline membrane. While some aspects of egg activation, such as initiation factors in mammals and environmental cues in sea animals, have been well-documented, the mechanics of egg activation in insects are less well-understood. For many insects, egg activation can be triggered independently of fertilization. In Drosophila melanogaster , egg activation occurs in the oviduct resulting in a single calcium wave propagating from the posterior pole of the oocyte. Here we use physical manipulations, genetics and live imaging to demonstrate the requirement of a volume increase for calcium entry at egg activation in ex vivo mature Drosophila oocytes. The addition of water, modified with sucrose to a specific osmolarity, is sufficient to trigger the calcium wave in the mature oocyte and the downstream events associated with egg activation. We show that the swelling process is regulated by the conserved osmoregulatory channels, aquaporins and DEGenerin/Epithelial Na + channels. Furthermore, through pharmacological and genetic disruption, we reveal a concentration-dependent requirement of transient receptor potential M channels to transport calcium, most probably from the perivitelline space, across the plasma membrane into the mature oocyte. Our data establish osmotic pressure as a mechanism that initiates egg activation in Drosophila and are consistent with previous work from evolutionarily distant insects, including dragonflies and mosquitos, and show remarkable similarities to the mechanism of egg activation in some plants.

scholarly journals Osmolarity-regulated swelling initiates egg activation in Drosophila

2021 ◽  
Author(s):  
Anna H. York-Andersen ◽  
Benjamin W. Wood ◽  
Elise L. Wilby ◽  
Alexander S. Berry ◽  
Timothy T. Weil
Keyword(s):  
Mature Oocyte ◽  
Posterior Pole ◽  
Vitelline Membrane ◽  
Egg Activation ◽  
Calcium Wave ◽  
Environmental Cues ◽  
Meiotic Cell ◽  
Volume Increase ◽  
Initiation Factors ◽  
Maternal Mrnas

ABSTRACTEgg activation is a series of highly coordinated processes that prepare the mature oocyte for embryogenesis. Typically associated with fertilisation, egg activation results in many downstream outcomes, including the resumption of the meiotic cell cycle, translation of maternal mRNAs and cross-linking of the vitelline membrane. While some aspects of egg activation, such as initiation factors in mammals and environmental cues in sea animals, have been well-documented, the mechanics of egg activation in insects are less well understood. For many insects, egg activation can be triggered independently of fertilisation. In Drosophila melanogaster, egg activation occurs in the oviduct resulting in a single calcium wave propagating from the posterior pole of the oocyte.Here we use physical manipulations, genetics and live imaging to demonstrate the requirement of a volume increase for calcium entry at egg activation in mature Drosophila oocytes. The addition of water, modified with sucrose to a specific osmolarity, is sufficient to trigger the calcium wave in the mature oocyte and the downstream events associated with egg activation. We show that the swelling process is regulated by the conserved osmoregulatory channels, aquaporins (AQPs) and DEGenerin/Epithelial Na+ (DEG/ENaC) channels. Furthermore, through pharmacological and genetic disruption, we reveal a concentration-dependent requirement of Trpm channels to transport calcium, most likely from the perivitelline space, across the plasma membrane into the mature oocyte.Our data establishes osmotic pressure as the mechanism that initiates egg activation in Drosophila and is consistent with previous work from evolutionarily distant insects, including dragonflies and mosquitos, and shows remarkable similarities to the mechanism of egg activation in some plants.

scholarly journals Capsazepine decreases corneal pain syndrome in severe dry eye disease

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Darine Fakih ◽  
Adrian Guerrero-Moreno ◽  
Christophe Baudouin ◽  
Annabelle Réaux-Le Goazigo ◽  
Stéphane Mélik Parsadaniantz
Keyword(s):  
In Situ Hybridization ◽  
Inflammatory Pain ◽  
Transient Receptor Potential ◽  
Ex Vivo ◽  
Receptor Potential ◽  
Eye Disease ◽  
Ocular Pain ◽  
Trpv1 Antagonist ◽  
Transient Receptor

Abstract Background Dry eye disease (DED) is a multifactorial disease of the ocular surface accompanied by neurosensory abnormalities. Here, we evaluated the effectiveness of transient receptor potential vanilloid-1 (TRPV1) blockade to alleviate ocular pain, neuroinflammation, and anxiety-like behavior associated with severe DED. Methods Chronic DED was induced by unilateral excision of the Harderian and extraorbital lacrimal glands of adult male mice. Investigations were conducted at 21 days after surgery. The mRNA levels of TRPV1, transient receptor potential ankyrin-1 (TRPA1), and acid-sensing ion channels 1 and 3 (ASIC1 and ASIC3) in the trigeminal ganglion (TG) were evaluated by RNAscope in situ hybridization. Multi-unit extracellular recording of ciliary nerve fiber activity was used to monitor spontaneous and stimulated (cold, heat, and acid) corneal nerve responsiveness in ex vivo eye preparations. DED mice received topical instillations of the TRPV1 antagonist (capsazepine) twice a day for 2 weeks from d7 to d21 after surgery. The expression of genes involved in neuropathic and inflammatory pain was evaluated in the TG using a global genomic approach. Chemical and mechanical corneal nociception and spontaneous ocular pain were monitored. Finally, anxiety-like behaviors were assessed by elevated plus maze and black and white box tests. Results First, in situ hybridization showed DED to trigger upregulation of TRPV1, TRPA1, ASIC1, and ASIC3 mRNA in the ophthalmic branch of the TG. DED also induced overexpression of genes involved in neuropathic and inflammatory pain in the TG. Repeated instillations of capsazepine reduced corneal polymodal responsiveness to heat, cold, and acidic stimulation in ex vivo eye preparations. Consistent with these findings, chronic capsazepine instillation inhibited the upregulation of genes involved in neuropathic and inflammatory pain in the TG of DED animals and reduced the sensation of ocular pain, as well as anxiety-like behaviors associated with severe DED. Conclusion These data provide novel insights on the effectiveness of TRPV1 antagonist instillation in alleviating abnormal corneal neurosensory symptoms induced by severe DED, opening an avenue for the repositioning of this molecule as a potential analgesic treatment for patients suffering from chronic DED.

scholarly journals TRPM8 function and expression in vagal sensory neurons and afferent nerves innervating guinea pig esophagus

2015 ◽  
Vol 308 (6) ◽  
pp. G489-G496 ◽  
Author(s):  
Xiaoyun Yu ◽  
Youtian Hu ◽  
Fei Ru ◽  
Marian Kollarik ◽  
Bradley J. Undem ◽  
...  
Keyword(s):  
Transient Receptor Potential ◽  
Calcium Influx ◽  
Ex Vivo ◽  
Receptor Potential ◽  
Sensory Transduction ◽  
Dependent Manner ◽  
Preferential Expression ◽  
C Fibers ◽  
C Fiber ◽  
Transient Receptor

Sensory transduction in esophageal afferents requires specific ion channels and receptors. TRPM8 is a new member of the transient receptor potential (TRP) channel family and participates in cold- and menthol-induced sensory transduction, but its role in visceral sensory transduction is still less clear. This study aims to determine TRPM8 function and expression in esophageal vagal afferent subtypes. TRPM8 agonist WS-12-induced responses were first determined in nodose and jugular neurons by calcium imaging and then investigated by whole cell patch-clamp recordings in Dil-labeled esophageal nodose and jugular neurons. Extracellular single-unit recordings were performed in nodose and jugular C fiber neurons using ex vivo esophageal-vagal preparations with intact nerve endings in the esophagus. TRPM8 mRNA expression was determined by single neuron RT-PCR in Dil-labeled esophageal nodose and jugular neurons. The TRPM8 agonist WS-12 elicited calcium influx in a subpopulation of jugular but not nodose neurons. WS-12 activated outwardly rectifying currents in esophageal Dil-labeled jugular but not nodose neurons in a dose-dependent manner, which could be inhibited by the TRPM8 inhibitor AMTB. WS-12 selectively evoked action potential discharges in esophageal jugular but not nodose C fibers. Consistently, TRPM8 transcripts were highly expressed in esophageal Dil-labeled TRPV1-positive jugular neurons. In summary, the present study demonstrated a preferential expression and function of TRPM8 in esophageal vagal jugular but not nodose neurons and C fiber subtypes. This provides a distinctive role of TRPM8 in esophageal sensory transduction and may lead to a better understanding of the mechanisms of esophageal sensation and nociception.

scholarly journals Mechanisms of the adenosine A2Areceptor-induced sensitization of esophageal C fibers

2016 ◽  
Vol 310 (3) ◽  
pp. G215-G223 ◽  
Author(s):  
M. Brozmanova ◽  
L. Mazurova ◽  
F. Ru ◽  
M. Tatar ◽  
Y. Hu ◽  
...  
Keyword(s):  
Transient Receptor Potential ◽  
Mechanical Response ◽  
Kinase Inhibitor ◽  
Ex Vivo ◽  
Receptor Potential ◽  
P2x Receptor ◽  
C Fibers ◽  
C Fiber ◽  
Transient Receptor ◽  
Stimulation Of

Clinical studies indicate that adenosine contributes to esophageal mechanical hypersensitivity in some patients with pain originating in the esophagus. We have previously reported that the esophageal vagal nodose C fibers express the adenosine A2Areceptor. Here we addressed the hypothesis that stimulation of the adenosine A2Areceptor induces mechanical sensitization of esophageal C fibers by a mechanism involving transient receptor potential A1 (TRPA1). Extracellular single fiber recordings of activity originating in C-fiber terminals were made in the ex vivo vagally innervated guinea pig esophagus. The adenosine A2Areceptor-selective agonist CGS21680 induced robust, reversible sensitization of the response to esophageal distention (10–60 mmHg) in a concentration-dependent fashion (1–100 nM). At the half-maximally effective concentration (EC50: ≈3 nM), CGS21680 induced an approximately twofold increase in the mechanical response without causing an overt activation. This sensitization was abolished by the selective A2Aantagonist SCH58261. The adenylyl cyclase activator forskolin mimicked while the nonselective protein kinase inhibitor H89 inhibited mechanical sensitization by CGS21680. CGS21680 did not enhance the response to the purinergic P2X receptor agonist α,β-methylene-ATP, indicating that CGS21680 does not nonspecifically sensitize to all stimuli. Mechanical sensitization by CGS21680 was abolished by pretreatment with two structurally different TRPA1 antagonists AP18 and HC030031 . Single cell RT-PCR and whole cell patch-clamp studies in isolated esophagus-specific nodose neurons revealed the expression of TRPA1 in A2A-positive C-fiber neurons and demonstrated that CGS21682 potentiated TRPA1 currents evoked by allylisothiocyanate. We conclude that stimulation of the adenosine A2Areceptor induces mechanical sensitization of nodose C fibers by a mechanism sensitive to TRPA1 antagonists indicating the involvement of TRPA1.

scholarly journals Novel Potentials of the DPP-4 Inhibitor Sitagliptin against Ischemia-Reperfusion (I/R) Injury in Rat Ex-Vivo Heart Model

2018 ◽  
Vol 19 (10) ◽  
pp. 3226 ◽  
Author(s):  
Amin Al-awar ◽  
Nikoletta Almási ◽  
Renáta Szabó ◽  
Istvan Takacs ◽  
Zsolt Murlasits ◽  
...  
Keyword(s):  
Transient Receptor Potential ◽  
Trp Channels ◽  
Ex Vivo ◽  
Ischemia Reperfusion ◽  
Oral Treatment ◽  
Receptor Potential ◽  
Transient Receptor Potential Vanilloid ◽  
Dipeptidyl Peptidase 4 ◽  
Regional Ischemia ◽  
Transient Receptor

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a class of oral anti-diabetic drugs, implicated in pleiotropic secondary cardioprotective effects. The aim of the study was to unveil the unknown and possible cardioprotective targets that can be exerted by sitagliptin (Sitg) against ischemia-reperfusion (I/R) injury. Male wistar rats received 2 weeks’ Sitg oral treatment of different doses (25, 50, 100, and 150 mg/kg/day), or saline as a Control. Hearts were then isolated and subjected to two different I/R injury protocols: 10 min perfusion, 45 min regional ischemia, and 120 min reperfusion for infarct size (IS) measurement, or: 10 min perfusion, 45 min regional ischemia and 10 min reperfusion for biochemical analysis: nitric oxide synthases (NOSs) and DPP-4 activity, glucagon-like peptide-1 (GLP-1), Calcium, transient receptor potential vanilloid (TRPV)-1 and calcitonin gene-related peptide (CGRP) levels, transient receptor potential canonical (TRPC)-1 and e-NOS protein expression. NOS inhibitor (l-NAME) and TRPV-1 inhibitor (Capsazepine) were utilized to confirm the implication of both signaling mechanisms in DPP-4 inhibition-induced at the level of IS. Findings show that Sitg (50 mg) resulted in significant decrease in IS and DPP-4 activity, and significant increase in GLP-1, NOS activity, e-NOS expression, TRPV-1 level and TRPC-1 expression, compared to controls. Results of CGRP are in line with TRPV-1, as a downstream regulatory effect. NOS system and transient receptor potential (TRP) channels can contribute to DPP-4 inhibition-mediated cardioprotection against I/R injury using Sitagliptin.

scholarly journals Simultaneous Deletion of Transient Receptor Potential Vanilloid 3 and Cacna1h Undermines Ca2+ Homeostasis in Oocytes and Fertility in Mice

2018 ◽  
Author(s):  
Aujan Mehregan ◽  
Goli Ardestani ◽  
Ingrid Carvacho ◽  
Rafael Fissore
Keyword(s):  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Functional Expression ◽  
Egg Activation ◽  
Transient Receptor Potential Vanilloid ◽  
Double Knockout ◽  
Knock Out ◽  
Transient Receptor ◽  
Mammalian Eggs ◽  
Channel Currents

In mammals, calcium (Ca2+) influx fills the endoplasmic reticulum, from where Ca2+ is released following fertilization to induce egg activation. However, an incomplete index of the plasma membrane channels and their specific contributions that underlie this influx in oocytes and eggs led us to simultaneously knock out the transient receptor potential vanilloid, member 3 (TRPV3) channel and the T-type channel, CaV3.2. Double knockout (dKO) females displayed subfertility and their oocytes and eggs showed significantly diminished Ca2+ store content and oscillations after fertilization compared to controls. We also found that the cell cycle stage during maturation determines the functional expression of channels whereby they show a distinct permeability to certain ions. In total, we demonstrate that TRPV3 and CaV3.2 are required for initiating physiological oscillations and that Ca2+ influx dictates the periodicity of oscillations during fertilization. dKO gametes will be indispensable to identify the complete native channel currents present in mammalian eggs.

TRPM7 channels mediate spontaneous Ca2+ fluctuations in growth plate chondrocytes that promote bone development

2019 ◽  
Vol 12 (576) ◽  
pp. eaaw4847 ◽  
Author(s):  
Nianchao Qian ◽  
Atsuhiko Ichimura ◽  
Daisuke Takei ◽  
Reiko Sakaguchi ◽  
Akihiro Kitani ◽  
...  
Keyword(s):  
Growth Plate ◽  
Transient Receptor Potential ◽  
Ex Vivo ◽  
Bone Development ◽  
Receptor Potential ◽  
Epiphyseal Growth Plate ◽  
Growth Plate Chondrocytes ◽  
Transient Receptor ◽  
Ex Vivo Culture

During endochondral ossification of long bones, the proliferation and differentiation of chondrocytes cause them to be arranged into layered structures constituting the epiphyseal growth plate, where they secrete the cartilage matrix that is subsequently converted into trabecular bone. Ca2+ signaling has been implicated in chondrogenesis in vitro. Through fluorometric imaging of bone slices from embryonic mice, we demonstrated that live growth plate chondrocytes generated small, cell-autonomous Ca2+ fluctuations that were associated with weak and intermittent Ca2+ influx. Several genes encoding Ca2+-permeable channels were expressed in growth plate chondrocytes, but only pharmacological inhibitors of transient receptor potential cation channel subfamily M member 7 (TRPM7) reduced the spontaneous Ca2+ fluctuations. The TRPM7-mediated Ca2+ influx was likely activated downstream of basal phospholipase C activity and was potentiated upon cell hyperpolarization induced by big-conductance Ca2+-dependent K+ channels. Bones from embryos in which Trpm7 was conditionally knocked out during ex vivo culture exhibited reduced outgrowth and displayed histological abnormalities accompanied by insufficient autophosphorylation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) in the growth plate. The link between TRPM7-mediated Ca2+ fluctuations and CaMKII-dependent chondrogenesis was further supported by experiments with chondrocyte-specific Trpm7 knockout mice. Thus, growth plate chondrocytes generate spontaneous, TRPM7-mediated Ca2+ fluctuations that promote self-maturation and bone development.

scholarly journals Cinnamaldehyde Induces Release of Cholecystokinin and Glucagon-Like Peptide 1 by Interacting with Transient Receptor Potential Ankyrin 1 in a Porcine Ex-Vivo Intestinal Segment Model

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2262
Author(s):  
Elout Van Liefferinge ◽  
Maximiliano Müller ◽  
Noémie Van Noten ◽  
Jeroen Degroote ◽  
Shahram Niknafs ◽  
...  
Keyword(s):  
Small Intestine ◽  
Transient Receptor Potential ◽  
Ex Vivo ◽  
Receptor Potential ◽  
Intestinal Segment ◽  
Gastric Function ◽  
Segment Model ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Transient Receptor

Cinnamaldehyde and capsaicin have been reported to exert effects on the gastric function, mediated by the interaction with transient receptor potential ankyrin channel 1 (TRPA1) and transient receptor potential vanilloid channel 1 (TRPV1), respectively. This study examined whether these compounds could trigger the release of cholecystokinin (CCK) and/or glucagon-like peptide 1 (GLP-1) in the pig’s gut in a porcine ex-vivo intestinal segment model. Furthermore, it was verified whether this response was mediated by TRPA1 or TRPV1 by using the channel’s antagonist. These gut peptides play a key role in the “intestinal brake", a feedback mechanism that influences the function of proximal parts of the gut. Structural analogues of cinnamaldehyde were screened as well, to explore structure-dependent activation. Results showed a significant effect of capsaicin on GLP-1 release in the proximal small intestine, TRPV1 independent. TRPA1 showed to be strongly activated by cinnamaldehyde, both in proximal and distal small intestine, evidenced by the release of CCK and GLP-1, respectively. Out of all structural derivates, cinnamaldehyde showed the highest affinity for TRPA1, which elucidates the importance of the α,β-unsaturated aldehyde moiety. In conclusion, cinnamaldehyde as a TRPA1 agonist, is a promising candidate to modulate gastric function, by activating intestinal brake mechanisms.

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