TRPM channel function in Caenorhabditis elegans

2007 ◽  
Vol 35 (1) ◽  
pp. 129-132 ◽  
Author(s):  
H.A. Baylis ◽  
K. Goyal

The nematode Caenorhabditis elegans contains over 20 genes for TRP (transient receptor potential) channels which include members of all of the subclasses identified in mammalian cells. These proteins include three members of the TRPM (TRP melastatin) family: gon-2 (abnormal gonad development), gtl-1 (gon-2-like 1) and gtl-2. Although studies of these genes are at an early stage, we are beginning to understand their functions in the life of C. elegans. Mutations in gon-2 have defective gonad formation because of failures in the cell division of the somatic gonad precursor cells. gon-2 and gtl-1 are both expressed in the intestine of the animal. Experiments on gon-2,gtl-1 double mutants show that they have a severe growth defect that is ameliorated by the addition of high levels of Mg2+ to the growth medium. gon-2,gtl-1 double mutants have defective magnesium homoeostasis and also have altered sensitivity to toxic levels of Ni2+. Furthermore gon-2 mutants have reduced levels of IORCa (outwardly rectifying calcium current) in the intestinal cells. Thus these two channels appear to play an important role in cation homoeostasis in C. elegans. In addition, perturbing the function of gon-2 and gtl-1 disrupts the ultradian defecation rhythm in C. elegans, suggesting that these channels play an important role in regulating this calcium-dependent rhythmic process. The tractability of C. elegans as an experimental animal and its amenability to techniques such as RNAi (RNA interference) and in vivo imaging make it an excellent system for an integrative analysis of TRPM function.

Cancers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 668
Author(s):  
Concetta Altamura ◽  
Maria Raffaella Greco ◽  
Maria Rosaria Carratù ◽  
Rosa Angela Cardone ◽  
Jean-François Desaphy

Ovarian cancer (OC) is the deadliest gynecologic cancer, due to late diagnosis, development of platinum resistance, and inadequate alternative therapy. It has been demonstrated that membrane ion channels play important roles in cancer processes, including cell proliferation, apoptosis, motility, and invasion. Here, we review the contribution of ion channels in the development and progression of OC, evaluating their potential in clinical management. Increased expression of voltage-gated and epithelial sodium channels has been detected in OC cells and tissues and shown to be involved in cancer proliferation and invasion. Potassium and calcium channels have been found to play a critical role in the control of cell cycle and in the resistance to apoptosis, promoting tumor growth and recurrence. Overexpression of chloride and transient receptor potential channels was found both in vitro and in vivo, supporting their contribution to OC. Furthermore, ion channels have been shown to influence the sensitivity of OC cells to neoplastic drugs, suggesting a critical role in chemotherapy resistance. The study of ion channels expression and function in OC can improve our understanding of pathophysiology and pave the way for identifying ion channels as potential targets for tumor diagnosis and treatment.


Biomolecules ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 590 ◽  
Author(s):  
Juliana Agostinho Lopes ◽  
Vinícius Peixoto Rodrigues ◽  
Marcelo Marucci Pereira Tangerina ◽  
Lucia Regina Machado da Rocha ◽  
Catarine Massucato Nishijima ◽  
...  

Machaerium hirtum (Vell.) Stellfeld (Fabaceae) known in Brazil as “jacaranda de espinho” or “espinheira santa nativa” is a medicinal plant commonly used in folk medicine to treat ulcers, cough and diarrhea. This study aimed to investigate the anti-inflammatory and antinociceptive effects of hydroalcoholic extracts from M. hirtum twig (HEMh) using in vivo experimental models of nociception through the involvement of transient receptor potential channels, acid-sensing ion channel (ASIC), nitrergic, opioidergic, glutamatergic, and supraspinal pathways. Our results revealed an antinociceptive effect of HEMh mediated by the opioidergic, l-arginine-nitric oxide and glutamate systems, as well as by interactions with TRPA1/ASIC channels. The anti-inflammatory effect of HEMh evaluated with a xylene-induced ear edema and by the involvement of arachidonic acid and prostaglandin E2 (PGE2) showed involvement of the COX pathway, based on observed decreases in PGE2 levels. A phytochemical investigation of the HEMh led to the isolation of α-amyrin, β-amyrin, allantoin, apigenin-7-methoxy-6-C-β-d-glucopyranoside, and apigenin-6-C-β-d-glucopyranosyl-8-C-β-d-xylopyranoside. In conclusion, the acute oral administration of HEMh inhibits the nociceptive behavioral response in animals through the nitrergic, opioid, glutamatergic pathways, and by inhibition of the TRPA1 and ASIC channels, without causing locomotor dysfunction. In addition, its anti-inflammatory effect is associated with the COX pathway and decreased PGE2 levels.


Author(s):  
Merle Marie Nicolai ◽  
Barbara Witt ◽  
Andrea Hartwig ◽  
Tanja Schwerdtle ◽  
Julia Bornhorst

AbstractThe identification of genotoxic agents and their potential for genotoxic alterations in an organism is crucial for risk assessment and approval procedures of the chemical and pharmaceutical industry. Classically, testing strategies for DNA or chromosomal damage focus on in vitro and in vivo (mainly rodent) investigations. In cell culture systems, the alkaline unwinding (AU) assay is one of the well-established methods for detecting the percentage of double-stranded DNA (dsDNA). By establishing a reliable lysis protocol, and further optimization of the AU assay for the model organism Caenorhabditis elegans (C. elegans), we provided a new tool for genotoxicity testing in the niche between in vitro and rodent experiments. The method is intended to complement existing testing strategies by a multicellular organism, which allows higher predictability of genotoxic potential compared to in vitro cell line or bacterial investigations, before utilizing in vivo (rodent) investigations. This also allows working within the 3R concept (reduction, refinement, and replacement of animal experiments), by reducing and possibly replacing animal testing. Validation with known genotoxic agents (bleomycin (BLM) and tert-butyl hydroperoxide (tBOOH)) proved the method to be meaningful, reproducible, and feasible for high-throughput genotoxicity testing, and especially preliminary screening.


2002 ◽  
Vol 156 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Valérie Denis ◽  
Martha S. Cyert

Calcium ions, present inside all eukaryotic cells, are important second messengers in the transduction of biological signals. In mammalian cells, the release of Ca2+ from intracellular compartments is required for signaling and involves the regulated opening of ryanodine and inositol-1,4,5-trisphosphate (IP3) receptors. However, in budding yeast, no signaling pathway has been shown to involve Ca2+ release from internal stores, and no homologues of ryanodine or IP3 receptors exist in the genome. Here we show that hyperosmotic shock provokes a transient increase in cytosolic Ca2+ in vivo. Vacuolar Ca2+, which is the major intracellular Ca2+ store in yeast, is required for this response, whereas extracellular Ca2+ is not. We aimed to identify the channel responsible for this regulated vacuolar Ca2+ release. Here we report that Yvc1p, a vacuolar membrane protein with homology to transient receptor potential (TRP) channels, mediates the hyperosmolarity induced Ca2+ release. After this release, low cytosolic Ca2+ is restored and vacuolar Ca2+ is replenished through the activity of Vcx1p, a Ca2+/H+ exchanger. These studies reveal a novel mechanism of internal Ca2+ release and establish a new function for TRP channels.


2005 ◽  
Vol 280 (23) ◽  
pp. 21893-21899 ◽  
Author(s):  
Ki Ho Park ◽  
Leonardo Hernandez ◽  
Shi-Qing Cai ◽  
Yi Wang ◽  
Federico Sesti

We have identified a family of ancillary subunits of K+ channels in Caenorhabditis elegans. MPS-1 and its related members MPS-2, MPS-3, and MPS-4 are detected in the nervous system of the nematode. Electrophysiological analysis in ASE neurons and mammalian cells and epigenetic inactivation by double-stranded RNA interference (RNAi) in vivo show that each MPS can associate with and functionally endow the voltage-gated K+ channel KVS-1. In the chemosensory neuron ADF, three different MPS subunits combine with KVS-1 to form both binary (MPS-1·KVS-1) and ternary (MPS-2·MPS-3·KVS-1) complexes. RNAi of mps-2, mps-3, or both, enhance the taste of the animal for sodium without altering the susceptibility to other attractants. When sodium is introduced in the test plate as background or as antagonist attractant, the nematode loses the ability to recognize a second attractant. Thus, it appears that the chemosensory apparatus of C. elegans uses sensory thresholds and that a voltage-gated K+ channel is specifically required for this mechanism.


2015 ◽  
Vol 112 (17) ◽  
pp. E2201-E2206 ◽  
Author(s):  
Kathryn B. Smedlund ◽  
Lutz Birnbaumer ◽  
Guillermo Vazquez

In previous in vitro studies, we showed that Transient Receptor Potential Canonical 3 (TRPC3), a calcium-permeable, nonselective cation channel endowed with high constitutive function, is an obligatory component of the inflammatory signaling that controls expression of the vascular cell adhesion molecule-1 (VCAM-1) and monocyte adhesion to coronary artery endothelial cells. Also, TRPC3 expression in these cells was found to be up-regulated by proatherogenic factors, which enhanced inflammation and VCAM-1 expression. However, it remained to be determined whether these in vitro findings were of relevance to atherosclerotic lesion development in vivo. To answer this important question in the present work, we generated mice with endothelial-specific overexpression of human TRPC3 in an Apoe knockout background (TgEST3ApoeKO) and examined lesions in the aortic sinus following 10 and 16 wk on a high-fat diet. No significant differences were found in size or complexity of early stage lesions (10 wk). However, advanced plaques (16 wk) from TgEST3ApoeKO mice exhibited a significant increase in size and macrophage content compared with nontransgenic littermate controls. Remarkably, this change was correlated with increased VCAM-1 and phospho-IkBα immunoreactivity along the endothelial lining of lesions from transgenic animals compared with controls. These findings validate the in vivo relevance of previous in vitro findings and represent, to our knowledge, the first in vivo evidence for a proatherogenic role of endothelial TRPC3.


2020 ◽  
Author(s):  
Bruno Nkambeu ◽  
Jennifer Ben Salem ◽  
Francis Beaudry

AbstractEugenol, a known vanilloid, was frequently used in dentistry as a local analgesic in addition, antibacterial and neuroprotective effects were also reported. Eugenol, capsaicin and many vanilloids are interacting with the transient receptor potential vanilloid 1 (TRPV1) in mammals and are activated by noxious heat. The pharmacological manipulation of the TRPV1 has been shown to have therapeutic value. Caenorhabditis elegans (C. elegans) express TRPV orthologs (e.g. OCR-2, OSM-9) and it is a commonly used animal model system to study nociception as it displays a well-defined and reproducible nocifensive behavior. After exposure to vanilloid solutions, C. elegans wild type (N2) and mutants were placed on petri dishes divided in quadrants for heat stimulation. Thermal avoidance index was used to phenotype each tested C. elegans experimental groups. The results showed that eugenol, vanillin and zingerone can hamper nocifensive response of C. elegans to noxious heat (32°C – 35°C) following a sustained exposition. Also, the effect was reversed 6h post exposition. Furthermore, eugenol and vanillin did not target specifically the OCR-2 or OSM-9 but zingerone did specifically target the OCR-2 similarly to capsaicin. Further structural and physicochemical analyses were performed. Key parameters for quantitative structure-property relationships (QSPR), quantitative structure-activity relationships (QSAR) and frontier orbital analyses suggest similarities and dissimilarities amongst the tested vanilloids and capsaicin in accordance with the relative anti-nociceptive effects observed.


2021 ◽  
Vol 22 (23) ◽  
pp. 12812
Author(s):  
Matthias Bosman ◽  
Dustin N. Krüger ◽  
Kasper Favere ◽  
Callan D. Wesley ◽  
Cédric H. G. Neutel ◽  
...  

Clinical and animal studies have demonstrated that chemotherapeutic doxorubicin (DOX) increases arterial stiffness, a predictor of cardiovascular risk. Despite consensus about DOX-impaired endothelium-dependent vasodilation as a contributing mechanism, some studies have reported conflicting results on vascular smooth muscle cell (VSMC) function after DOX treatment. The present study aimed to investigate the effects of DOX on VSMC function. To this end, mice received a single injection of 4 mg DOX/kg, or mouse aortic segments were treated ex vivo with 1 μM DOX, followed by vascular reactivity evaluation 16 h later. Phenylephrine (PE)-induced VSMC contraction was decreased after DOX treatment. DOX did not affect the transient PE contraction dependent on Ca2+ release from the sarcoplasmic reticulum (0 mM Ca2+), but it reduced the subsequent tonic phase characterised by Ca2+ influx. These findings were supported by similar angiotensin II and attenuated endothelin-1 contractions. The involvement of voltage-gated Ca2+ channels in DOX-decreased contraction was excluded by using levcromakalim and diltiazem in PE-induced contraction and corroborated by similar K+ and serotonin contractions. Despite the evaluation of multiple blockers of transient receptor potential channels, the exact mechanism for DOX-decreased VSMC contraction remains elusive. Surprisingly, DOX reduced ex vivo but not in vivo arterial stiffness, highlighting the importance of appropriate timing for evaluating arterial stiffness in DOX-treated patients.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kohei Ohnishi ◽  
Shigeru Saito ◽  
Toru Miura ◽  
Akane Ohta ◽  
Makoto Tominaga ◽  
...  

Abstract Caenorhabditis elegans (C. elegans) exhibits cold tolerance and temperature acclimatisation regulated by a small number of head sensory neurons, such as the ADL temperature-sensing neurons that express three transient receptor potential vanilloid (TRPV) channel subunits, OSM-9, OCR-2, and OCR-1. Here, we show that an OSM-9/OCR-2 regulates temperature acclimatisation and acts as an accessorial warmth-sensing receptor in ADL neurons. Caenorhabditis elegans TRPV channel mutants showed abnormal temperature acclimatisation. Ectopic expression of OSM-9 and OCR-2 in non-warming-responsive gustatory neurons in C. elegans and Xenopus oocytes revealed that OSM-9 and OCR-2 cooperatively responded to warming; however, neither TRPV subunit alone was responsive to warming. A warming-induced OSM-9/OCR-2-mediated current was detectable in Xenopus oocytes, yet ADL in osm-9 ocr-2 double mutant responds to warming; therefore, an OSM-9/OCR-2 TRPV channel and as yet unidentified temperature receptor might coordinate transmission of temperature signalling in ADL temperature-sensing neurons. This study demonstrates direct sensation of warming by TRPV channels in C. elegans.


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