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Fukuda J, Matsuda K, Sato G, Kitamura Y, Uno A, Takeda N. Effects of sodium bicarbonate solution on hypergravity-induced Fos expression in neurons of the amygdala in rats: Implication of sodium bicarbonate therapy for vertigo. Auris Nasus Larynx 2024; 51:733-737. [PMID: 38838426 DOI: 10.1016/j.anl.2024.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 04/14/2024] [Accepted: 05/09/2024] [Indexed: 06/07/2024]
Abstract
OBJECTIVE In Japan, intravenous injection of a 7 % solution of sodium bicarbonate (NaHCO3) had been originally developed to inhibit motion sickness and then have long been used to treat vertigo. Previously, we reported that Fos-positive neurons appear in the amygdala after hypergravity stimulation in rats. In the present study, we examined whether injection of 7 % NaHCO3 inhibits hypergravity-induced Fos expression in the neurons in the central nucleus of the amygdala in rats. METHODS Rats were exposed to 2 G hypergravity in an animal centrifuge device for 3 h. A solution of 7 % NaHCO3 at a dose of 4 mM/kg was injected intraperitoneally before 2 G hypergraviy. Fos-positive neurons in the amygdala were stained immunohistochemically. RESULTS The number of Fos-positive neurons in the central nucleus of the amygdala was significantly increased after 2 G hypergravity in rats that received no drugs or saline, compared to that in rats exposed only to the noise of the centrifuge and received 7 % NaHCO3 solution. The number of Fos-positive neurons in the central nucleus of the amygdala after 2 G hypergravity was significantly decreased in rats that received 7 % NaHCO3 solution, compared to that in rats that received no drugs or saline. CONCLUSION Since Fos expression is a marker of activated neurons, the present findings suggest that hypergravity activates the amygdala and that administration of 7 % NaHCO3 suppresses hypergravity-induced activation of the amygdala. Hypergravity disturbs spatial orientation to produce motion sickness and the amygdala is involved in fear response. Recently, Ziemann et al. suggested that fear-evoking stimuli reduce the pH in the amygdala to activate it, leading to induction of fear behavior and that administering HCO3- attenuates fear behavior [Cell 2009; 139: 1012-1021]. Therefore, it is possible that hypergravity reduces the pH in the amygdala to activate it, thereby inducing the fear associated with motion sickness and that administration of 7 % NaHCO3 increases the brain pH thereby suppressing hypergravity-induced activation of the amygdala and inhibiting the fear associated with motion sickness. In patients with vertigo, 7 % NaHCO3 therapy may increase the brain pH thereby suppressing the activation of the amygdala and inhibiting the fear associated with vertigo to elicit a beneficial clinical effect.
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Affiliation(s)
- Junya Fukuda
- Department of Otolaryngology-Head and Neck Surgery, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Kazunori Matsuda
- Department of Otolaryngology-Head and Neck Surgery, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Go Sato
- Department of Otolaryngology-Head and Neck Surgery, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Yoshiaki Kitamura
- Department of Otolaryngology-Head and Neck Surgery, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Atsuhiko Uno
- Department of Otolaryngology-Head and Neck Surgery, Osaka General Medical Center, Osaka, Japan
| | - Noriaki Takeda
- Department of Otolaryngology-Head and Neck Surgery, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan.
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2
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Ji R, Chang L, An C, Zhang J. Proton-sensing ion channels, GPCRs and calcium signaling regulated by them: implications for cancer. Front Cell Dev Biol 2024; 12:1326231. [PMID: 38505262 PMCID: PMC10949864 DOI: 10.3389/fcell.2024.1326231] [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: 10/25/2023] [Accepted: 02/14/2024] [Indexed: 03/21/2024] Open
Abstract
Extracellular acidification of tumors is common. Through proton-sensing ion channels or proton-sensing G protein-coupled receptors (GPCRs), tumor cells sense extracellular acidification to stimulate a variety of intracellular signaling pathways including the calcium signaling, which consequently exerts global impacts on tumor cells. Proton-sensing ion channels, and proton-sensing GPCRs have natural advantages as drug targets of anticancer therapy. However, they and the calcium signaling regulated by them attracted limited attention as potential targets of anticancer drugs. In the present review, we discuss the progress in studies on proton-sensing ion channels, and proton-sensing GPCRs, especially emphasizing the effects of calcium signaling activated by them on the characteristics of tumors, including proliferation, migration, invasion, metastasis, drug resistance, angiogenesis. In addition, we review the drugs targeting proton-sensing channels or GPCRs that are currently in clinical trials, as well as the relevant potential drugs for cancer treatments, and discuss their future prospects. The present review aims to elucidate the important role of proton-sensing ion channels, GPCRs and calcium signaling regulated by them in cancer initiation and development. This review will promote the development of drugs targeting proton-sensing channels or GPCRs for cancer treatments, effectively taking their unique advantage as anti-cancer drug targets.
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Affiliation(s)
- Renhui Ji
- Foundational and Translational Medical Research Center, Department of Allergy and General Surgery, Hohhot First Hospital, Hohhot, China
- Department of Pathophysiology, Basic Medicine College of Inner Mongolia Medical University, Hohhot, China
| | - Li Chang
- Foundational and Translational Medical Research Center, Department of Allergy and General Surgery, Hohhot First Hospital, Hohhot, China
- Department of Pathophysiology, Basic Medicine College of Inner Mongolia Medical University, Hohhot, China
| | - Caiyan An
- Foundational and Translational Medical Research Center, Department of Allergy and General Surgery, Hohhot First Hospital, Hohhot, China
| | - Junjing Zhang
- Foundational and Translational Medical Research Center, Department of Allergy and General Surgery, Hohhot First Hospital, Hohhot, China
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3
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Li Q, Li J. NGF contributes to activities of acid-sensing ion channels in dorsal root ganglion neurons of male rats with experimental peripheral artery disease. Physiol Rep 2024; 12:e15933. [PMID: 38312021 PMCID: PMC10839628 DOI: 10.14814/phy2.15933] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/15/2024] [Accepted: 01/15/2024] [Indexed: 02/06/2024] Open
Abstract
A feature of peripheral artery diseases (PAD) includes limb ischemia/reperfusion (I/R) and ischemia. Both I/R and ischemia amplify muscle afferent nerve-activated reflex sympathetic nervous and blood pressure responses (termed as exercise pressor reflex). Nevertheless, the underlying mechanisms responsible for the exaggerated autonomic responses in PAD are undetermined. Previous studies suggest that acid-sensing ion channels (ASICs) in muscle dorsal root ganglion (DRG) play a leading role in regulating the exercise pressor reflex in PAD. Thus, we determined if signaling pathways of nerve growth factor (NGF) contribute to the activities of ASICs in muscle DRG neurons of PAD. In particular, we examined ASIC1a and ASIC3 currents in isolectin B4 -negative muscle DRG neurons, a distinct subpopulation depending on NGF for survival. Hindlimb I/R and ischemia were obtained in male rats. In results, femoral artery occlusion increased the levels of NGF and NGF-stimulated TrkA receptor in DRGs, whereas they led to upregulation of ASIC3 but not ASIC1a. In addition, application of NGF onto DRG neurons increased the density of ASIC3 currents and the effect of NGF was significantly attenuated by TrkA antagonist GW441756. Moreover, the enhancing effect of NGF on the density of ASIC3-like currents was decreased by the respective inhibition of intracellular signaling pathways, namely JNK and NF-κB, by antagonists SP600125 and PDTC. Our results suggest contribution of NGF to the activities of ASIC3 currents via JNK and NF-κB signaling pathways in association with the exercise pressor reflex in experimental PAD.
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Affiliation(s)
- Qin Li
- Heart and Vascular InstituteThe Pennsylvania State University College of MedicineHersheyPennsylvaniaUSA
| | - Jianhua Li
- Heart and Vascular InstituteThe Pennsylvania State University College of MedicineHersheyPennsylvaniaUSA
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4
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Liu Y, Ma J, DesJarlais RL, Hagan R, Rech J, Liu C, Miller R, Schoellerman J, Luo J, Letavic M, Grasberger B, Maher MP. Molecular determinants of ASIC1 modulation by divalent cations. Sci Rep 2024; 14:2320. [PMID: 38282035 PMCID: PMC10822848 DOI: 10.1038/s41598-024-52845-3] [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: 09/07/2023] [Accepted: 01/24/2024] [Indexed: 01/30/2024] Open
Abstract
Acid-sensing ion channels (ASICs) are proton-gated cation channels widely expressed in the nervous system. ASIC gating is modulated by divalent cations as well as small molecules; however, the molecular determinants of gating modulation by divalent cations are not well understood. Previously, we identified two small molecules that bind to ASIC1a at a novel site in the acidic pocket and modulate ASIC1 gating in a manner broadly resembling divalent cations, raising the possibility that these small molecules may help to illuminate the molecular determinants of gating modulation by divalent cations. Here, we examined how these two groups of modulators might interact as well as mutational effects on ASIC1a gating and its modulation by divalent cations. Our results indicate that binding of divalent cations to an acidic pocket site plays a key role in gating modulation of the channel.
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Affiliation(s)
- Yi Liu
- Neuroscience Discovery, Janssen Research & Development, L.L.C., 3210 Merryfield Row, San Diego, CA, 92121, USA
| | - Jichun Ma
- Therapeutics Discovery, Janssen Research & Development, L.L.C., Welsh & McKean Roads, P.O. Box 776, Spring House, PA, 19477, USA
| | - Renee L DesJarlais
- Therapeutics Discovery, Janssen Research & Development, L.L.C., Welsh & McKean Roads, P.O. Box 776, Spring House, PA, 19477, USA
| | - Rebecca Hagan
- Neuroscience Discovery, Janssen Research & Development, L.L.C., 3210 Merryfield Row, San Diego, CA, 92121, USA
| | - Jason Rech
- Therapeutics Discovery, Janssen Research & Development, L.L.C., 3210 Merryfield Row, San Diego, CA, 92121, USA
| | - Changlu Liu
- Neuroscience Discovery, Janssen Research & Development, L.L.C., 3210 Merryfield Row, San Diego, CA, 92121, USA
| | - Robyn Miller
- Therapeutics Discovery, Janssen Research & Development, L.L.C., Welsh & McKean Roads, P.O. Box 776, Spring House, PA, 19477, USA
| | - Jeffrey Schoellerman
- Neuroscience Discovery, Janssen Research & Development, L.L.C., 3210 Merryfield Row, San Diego, CA, 92121, USA
| | - Jinquan Luo
- Therapeutics Discovery, Janssen Research & Development, L.L.C., Welsh & McKean Roads, P.O. Box 776, Spring House, PA, 19477, USA
| | - Michael Letavic
- Therapeutics Discovery, Janssen Research & Development, L.L.C., 3210 Merryfield Row, San Diego, CA, 92121, USA
| | - Bruce Grasberger
- Therapeutics Discovery, Janssen Research & Development, L.L.C., Welsh & McKean Roads, P.O. Box 776, Spring House, PA, 19477, USA
| | - Michael P Maher
- Neuroscience Discovery, Janssen Research & Development, L.L.C., 3210 Merryfield Row, San Diego, CA, 92121, USA.
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Furukawa Y, Tagashira I. Aromatic amino acids in the finger domain of the FMRFamide-gated Na[Formula: see text] channel are involved in the FMRFamide recognition and the activation. Pflugers Arch 2023:10.1007/s00424-023-02817-9. [PMID: 37289212 DOI: 10.1007/s00424-023-02817-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 04/18/2023] [Accepted: 04/20/2023] [Indexed: 06/09/2023]
Abstract
FMRFamide-gated Na[Formula: see text] channel (FaNaC) is a member of the DEG/ENaC family and activated by a neuropeptide, FMRFamide. Structural information about the FMRFamide-dependent gating is, however, still elusive. Because two phenylalanines of FMRFamide are essential for the activation of FaNaC, we hypothesized that aromatic-aromatic interaction between FaNaC and FMRFamide is critical for FMRFamide recognition and/or the activation gating. Here, we focused on eight conserved aromatic residues in the finger domain of FaNaCs and tested our hypothesis by mutagenic analysis and in silico docking simulations. The mutation of conserved aromatic residues in the finger domain reduced the FMRFamide potency, suggesting that the conserved aromatic residues are involved in the FMRFamide-dependent activation. The kinetics of the FMRFamide-gated currents were also modified substantially in some mutants. Some results of docking simulations were consistent with a hypothesis that the aromatic-aromatic interaction between the aromatic residues in FaNaC and FMRFamide is involved in the FMRFamide recognition. Collectively, our results suggest that the conserved aromatic residues in the finger domain of FaNaC are important determinants of the ligand recognition and/or the activation gating in FaNaC.
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Affiliation(s)
- Yasuo Furukawa
- Laboratory of Neurobiology, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, Japan.
- Laboratory of Neurobiology, Graduate School of Integrated Sciences of Life, Hiroshima University, Kagamiyama 1-7-1, Higashi-Hiroshima, 739-8521, Japan.
| | - Iori Tagashira
- Laboratory of Neurobiology, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, Japan
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Pliushcheuskaya P, Künze G. Recent Advances in Computer-Aided Structure-Based Drug Design on Ion Channels. Int J Mol Sci 2023; 24:ijms24119226. [PMID: 37298178 DOI: 10.3390/ijms24119226] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/16/2023] [Accepted: 05/22/2023] [Indexed: 06/12/2023] Open
Abstract
Ion channels play important roles in fundamental biological processes, such as electric signaling in cells, muscle contraction, hormone secretion, and regulation of the immune response. Targeting ion channels with drugs represents a treatment option for neurological and cardiovascular diseases, muscular degradation disorders, and pathologies related to disturbed pain sensation. While there are more than 300 different ion channels in the human organism, drugs have been developed only for some of them and currently available drugs lack selectivity. Computational approaches are an indispensable tool for drug discovery and can speed up, especially, the early development stages of lead identification and optimization. The number of molecular structures of ion channels has considerably increased over the last ten years, providing new opportunities for structure-based drug development. This review summarizes important knowledge about ion channel classification, structure, mechanisms, and pathology with the main focus on recent developments in the field of computer-aided, structure-based drug design on ion channels. We highlight studies that link structural data with modeling and chemoinformatic approaches for the identification and characterization of new molecules targeting ion channels. These approaches hold great potential to advance research on ion channel drugs in the future.
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Affiliation(s)
- Palina Pliushcheuskaya
- Institute for Drug Discovery, Medical Faculty, University of Leipzig, Brüderstr. 34, D-04103 Leipzig, Germany
| | - Georg Künze
- Institute for Drug Discovery, Medical Faculty, University of Leipzig, Brüderstr. 34, D-04103 Leipzig, Germany
- Interdisciplinary Center for Bioinformatics, University of Leipzig, Härtelstr. 16-18, D-04107 Leipzig, Germany
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7
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Evlanenkov KK, Komarova MS, Dron MY, Nikolaev MV, Zhukovskaya ON, Gurova NA, Tikhonov DB. Derivatives of 2-aminobenzimidazole potentiate ASIC open state with slow kinetics of activation and desensitization. Front Physiol 2023; 14:1018551. [PMID: 36711018 PMCID: PMC9878307 DOI: 10.3389/fphys.2023.1018551] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Accepted: 01/04/2023] [Indexed: 01/15/2023] Open
Abstract
The pharmacology of acid-sensitive ion channels (ASICs) is diverse, but potent and selective modulators, for instance for ASIC2a, are still lacking. In the present work we studied the effect of five 2-aminobenzimidazole derivatives on native ASICs in rat brain neurons and recombinant receptors expressed in CHO cells using the whole-cell patch clamp method. 2-aminobenzimidazole selectively potentiated ASIC3. Compound Ru-1355 strongly enhanced responses of ASIC2a and caused moderate potentiation of native ASICs and heteromeric ASIC1a/ASIC2a. The most active compound, Ru-1199, caused the strongest potentiation of ASIC2a, but also potentiated native ASICs, ASIC1a and ASIC3. The potentiating effects depended on the pH and was most pronounced with intermediate acidifications. In the presence of high concentrations of Ru-1355 and Ru-1199, the ASIC2a responses were biphasic, the initial transient currents were followed by slow component. These slow additional currents were weakly sensitive to the acid-sensitive ion channels pore blocker diminazene. We also found that sustained currents mediated by ASIC2a and ASIC3 are less sensitive to diminazene than the peak currents. Different sensitivities of peak and sustained components to the pore-blocking drug suggest that they are mediated by different open states. We propose that the main mechanism of action of 2-aminobenzimidazole derivatives is potentiation of the open state with slow kinetics of activation and desensitization.
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Affiliation(s)
| | - Margarita S Komarova
- I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, St. Petersburg, Russia
| | - Mikhail Y Dron
- I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, St. Petersburg, Russia
| | - Maxim V Nikolaev
- I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, St. Petersburg, Russia
| | - Olga N Zhukovskaya
- Research Institute of Physical and Organic Chemistry, Southern Federal University, Rostov-on-Don, Russia
| | - Nataliya A Gurova
- Department of Pharmacology and Bioinformatics, Volgograd State Medical University, Volgograd, Russia
| | - Denis B Tikhonov
- I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, St. Petersburg, Russia,*Correspondence: Denis B Tikhonov,
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Christie M, Friesen Westley J, Suresh B, Baiazitov Ramil Y, Wu D, Karloff Diane B, Chang-Sun L, Young-Choon M, Hongyu R, Jairo S, Yuki T, Priya V, Welch Ellen M, Xiaojiao X, Jin Z. Guanidino Quinazolines and Pyrimidines Promote Readthrough of Premature Termination Codons in Cells with Native Nonsense Mutations. Bioorg Med Chem Lett 2022; 76:128989. [PMID: 36150638 DOI: 10.1016/j.bmcl.2022.128989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 08/26/2022] [Accepted: 09/09/2022] [Indexed: 11/25/2022]
Abstract
Using small molecules to induce readthrough of premature termination codons is a promising therapeutic approach to treating genetic diseases and cancers caused by nonsense mutations, as evidenced by the widespread use of ataluren to treat nonsense mutation Duchene muscular dystrophy. Herein we describe a series of novel guanidino quinazoline and pyrimidine scaffolds that induce readthrough in both HDQ-P1 mammary carcinoma cells and mdx myotubes. Linkage of basic, tertiary amines with aliphatic, hydrophobic substituents to the terminal guanidine nitrogen of these scaffolds led to significant potency increases. Further potency gains were achieved by flanking the pyrimidine ring with hydrophobic substituents, inducing readthrough at concentrations as low as 120 nM and demonstrating the potential of these compounds to be used either in combination with ataluren or as stand-alone therapeutics.
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Affiliation(s)
- Morrill Christie
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ, 07080, USA
| | - J Friesen Westley
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ, 07080, USA
| | - Babu Suresh
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ, 07080, USA
| | - Y Baiazitov Ramil
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ, 07080, USA
| | - Du Wu
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ, 07080, USA
| | - B Karloff Diane
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ, 07080, USA
| | - Lee Chang-Sun
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ, 07080, USA
| | - Moon Young-Choon
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ, 07080, USA
| | - Ren Hongyu
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ, 07080, USA
| | - Sierra Jairo
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ, 07080, USA
| | - Tomizawa Yuki
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ, 07080, USA
| | - Vazirani Priya
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ, 07080, USA
| | - M Welch Ellen
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ, 07080, USA
| | - Xue Xiaojiao
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ, 07080, USA
| | - Zhuo Jin
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ, 07080, USA
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Zhang L, Zheng L, Yang X, Yao S, Wang H, An J, Jin H, Wen G, Tuo B. Pathology and physiology of acid‑sensitive ion channels in the digestive system (Review). Int J Mol Med 2022; 50:94. [PMID: 35616162 PMCID: PMC9170189 DOI: 10.3892/ijmm.2022.5150] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 05/11/2022] [Indexed: 11/16/2022] Open
Abstract
As a major proton-gated cation channel, acid-sensitive ion channels (ASICs) can perceive large extracellular pH changes. ASICs play an important role in the occurrence and development of diseases of various organs and tissues including in the heart, brain, and gastrointestinal tract, as well as in tumor proliferation, invasion, and metastasis in acidosis and regulation of an acidic microenvironment. The permeability of ASICs to sodium and calcium ions is the basis of their physiological and pathological roles in the body. This review summarizes the physiological and pathological mechanisms of ASICs in digestive system diseases, which plays an important role in the early diagnosis, treatment, and prognosis of digestive system diseases related to ASIC expression.
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Affiliation(s)
- Li Zhang
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Liming Zheng
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Xingyue Yang
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Shun Yao
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Hui Wang
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Jiaxing An
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Hai Jin
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Guorong Wen
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Biguang Tuo
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
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10
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Lu Y, Stec DE, Liu R, Ryan M, Drummond HA. βENaC and ASIC2 associate in VSMCs to mediate pressure-induced constriction in the renal afferent arteriole. Am J Physiol Renal Physiol 2022; 322:F498-F511. [PMID: 35285274 PMCID: PMC8977180 DOI: 10.1152/ajprenal.00003.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 02/17/2022] [Accepted: 03/03/2022] [Indexed: 11/22/2022] Open
Abstract
In independent studies, our laboratory has shown the importance of the degenerin proteins β-epithelial Na+ channel (βENaC) and acid-sensing ion channel 2 (ASIC2) in pressure-induced constriction (PIC) in renal interlobar arteries. Most, but not all, of the PIC response is abolished in mice lacking normal levels of βENaC or in ASIC2-null mice, indicating that the functions of βENaC and ASIC2 cannot fully compensate for the loss of the other. Degenerin proteins are known to associate and form heteromeric channels in expression systems, but whether they interact biochemically and functionally in vascular smooth muscle cells is unknown. We hypothesized that βENaC and ASIC2 interact to mediate PIC responses in renal vessels. To address this possibility, we 1) used biochemical approaches to show that βENaC associates into high-molecular-weight complexes and immunoprecipitants with ASIC2 in vascular smooth muscle cells and then 2) examined PIC in renal afferent arterioles in mice lacking normal levels of βENaC (βENaCm/m) or/and ASIC2 (ASIC2-/-) using the isolated afferent arteriole-attached glomerulus preparation. We found that the sensitivity of the PIC response (slope of the relationship between intraluminal pressure and percent myogenic tone) decreased to 26%, 27%, and -8% of wild-type controls in ASIC2-/-, βENaCm/m, and ASIC2-/-/βENaCm/m groups, respectively, suggesting that the PIC response was totally abolished in mice deficient in both ASIC2 and βENaC. Surprisingly, we found that resting internal diameters were 20-30% lower (60 mmHg, Ca2+ free) in ASIC2-/-/βENaCm/m (11.3 ± 0.5 µm) mice compared with control (14.4 ± 0.6 µm, P = 0.0007, independent two-tailed t test) or singly modified (15.7 ± 1.0 to 16.3 ± 1.1 µm) mice, suggesting compensatory vasoconstriction or remodeling. We then examined mean arterial blood pressure (MAP) using radiotelemetry and glomerular injury using histological examination of renal sections. We found that 24-h MAP was mildly elevated (+8 mmHg) in ASIC2-/-/βENaCm/m mice versus wild-type controls and the glomerular injury score was modestly increased by 38%. These findings demonstrate that myogenic constriction in afferent arterioles is dependent on normal expression of βENaC and ASIC2 and that mice lacking normal levels of ASIC2 and βENaC have mild renal injury and increased MAP.NEW & NOTEWORTHY Transmission of systemic blood pressure to delicate renal microvessels is a primary determinant of vascular injury in chronic kidney disease progression to end-stage renal disease. Here, we identified two degenerin family members, with an evolutionary link to mechanosensing, that interact biochemically and functionally to regulate systemic blood pressure and renal injury. Thus, degenerin proteins may serve as a target for the development of therapies to prevent or delay renal disease progression.
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Affiliation(s)
- Yan Lu
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - David E Stec
- Department of Physiology and Biophysics and the Center for Excellence in Cardiovascular Renal Research, University of Mississippi Medical Center, Jackson, Mississippi
| | - Ruisheng Liu
- Department of Molecular Pharmacology and Physiology, University of South Florida, College of Medicine, Tampa, Florida
| | - Michael Ryan
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina
| | - Heather A Drummond
- Department of Physiology and Biophysics and the Center for Excellence in Cardiovascular Renal Research, University of Mississippi Medical Center, Jackson, Mississippi
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11
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Sivils A, Yang F, Wang JQ, Chu XP. Acid-Sensing Ion Channel 2: Function and Modulation. MEMBRANES 2022; 12:membranes12020113. [PMID: 35207035 PMCID: PMC8880099 DOI: 10.3390/membranes12020113] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 01/08/2023]
Abstract
Acid-sensing ion channels (ASICs) have an important influence on human physiology and pathology. They are members of the degenerin/epithelial sodium channel family. Four genes encode at least six subunits, which combine to form a variety of homotrimers and heterotrimers. Of these, ASIC1a homotrimers and ASIC1a/2 heterotrimers are most widely expressed in the central nervous system (CNS). Investigations into the function of ASIC1a in the CNS have revealed a wealth of information, culminating in multiple contemporary reviews. The lesser-studied ASIC2 subunits are in need of examination. This review will focus on ASIC2 in health and disease, with discussions of its role in modulating ASIC function, synaptic targeting, cardiovascular responses, and pharmacology, while exploring evidence of its influence in pathologies such as ischemic brain injury, multiple sclerosis, epilepsy, migraines, drug addiction, etc. This information substantiates the ASIC2 protein as a potential therapeutic target for various neurological, psychological, and cerebrovascular diseases.
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Affiliation(s)
| | | | | | - Xiang-Ping Chu
- Correspondence: ; Tel.: +1-816-235-2248; Fax: +1-816-235-6517
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12
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Taugher RJ, Wunsch AM, Wang GZ, Chan AC, Dlouhy BJ, Wemmie JA. Post-acquisition CO 2 Inhalation Enhances Fear Memory and Depends on ASIC1A. Front Behav Neurosci 2021; 15:767426. [PMID: 34776896 PMCID: PMC8585996 DOI: 10.3389/fnbeh.2021.767426] [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: 09/01/2021] [Accepted: 10/04/2021] [Indexed: 11/25/2022] Open
Abstract
A growing body of evidence suggests that memories of fearful events may be altered after initial acquisition or learning. Although much of this work has been done in rodents using Pavlovian fear conditioning, it may have important implications for fear memories in humans such as in post-traumatic stress disorder (PTSD). A recent study suggested that cued fear memories, made labile by memory retrieval, were made additionally labile and thus more vulnerable to subsequent modification when mice inhaled 10% carbon dioxide (CO2) during retrieval. In light of this finding, we hypothesized that 10% CO2 inhalation soon after fear acquisition might affect memory recall 24 h later. We found that both cue and context fear memory were increased by CO2 exposure after fear acquisition. The effect of CO2 was time-dependent, as CO2 inhalation administered 1 or 4 h after cued fear acquisition increased fear memory, whereas CO2 inhalation 4 h before or 24 h after cued fear acquisition did not increase fear memory. The ability of CO2 exposure following acquisition to enhance fear memory was not a general consequence of stress, as restraining mice after acquisition did not alter cued fear memory. The memory-enhancing action of CO2 may be relatively specific to fear conditioning as novel object recognition was impaired by post-training CO2 inhalation. To explore the molecular underpinnings of these effects, we tested if they depended on the acid-sensing ion channel-1a (ASIC1A), a proton-gated cation channel that mediates other effects of CO2, likely via its ability to sense acidosis induced during CO2 inhalation. We found that CO2 inhalation did not alter cued or context fear memory in Asic1a–/– mice, suggesting that this phenomenon critically depends on ASIC1A. These results suggest that brain acidosis around the time of a traumatic event may enhance memory of the trauma, and may thus constitute an important risk factor for developing PTSD. Moreover, preventing peritraumatic acidosis might reduce risk of PTSD.
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Affiliation(s)
- Rebecca J Taugher
- Department of Psychiatry, University of Iowa, Iowa City, IA, United States.,Department of Veterans Affairs Medical Center, Iowa City, IA, United States
| | - Amanda M Wunsch
- Department of Psychiatry, University of Iowa, Iowa City, IA, United States.,Department of Veterans Affairs Medical Center, Iowa City, IA, United States
| | - Grace Z Wang
- Department of Psychiatry, University of Iowa, Iowa City, IA, United States.,Department of Veterans Affairs Medical Center, Iowa City, IA, United States
| | - Aubrey C Chan
- Department of Psychiatry, University of Iowa, Iowa City, IA, United States.,Department of Veterans Affairs Medical Center, Iowa City, IA, United States.,Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA, United States.,Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, United States.,Department of Internal Medicine, University of Iowa, Iowa City, IA, United States
| | - Brian J Dlouhy
- Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA, United States.,Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, United States.,Department of Neurosurgery, University of Iowa, Iowa City, IA, United States
| | - John A Wemmie
- Department of Psychiatry, University of Iowa, Iowa City, IA, United States.,Department of Veterans Affairs Medical Center, Iowa City, IA, United States.,Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA, United States.,Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, United States.,Department of Neurosurgery, University of Iowa, Iowa City, IA, United States.,Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA, United States.,Roy J. Carver Chair of Psychiatry and Neuroscience, University of Iowa, Iowa City, IA, United States
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13
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Mango D, Nisticò R. Neurodegenerative Disease: What Potential Therapeutic Role of Acid-Sensing Ion Channels? Front Cell Neurosci 2021; 15:730641. [PMID: 34690702 PMCID: PMC8531221 DOI: 10.3389/fncel.2021.730641] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 09/15/2021] [Indexed: 12/19/2022] Open
Abstract
Acidic pH shift occurs in many physiological neuronal activities such as synaptic transmission and synaptic plasticity but also represents a characteristic feature of many pathological conditions including inflammation and ischemia. Neuroinflammation is a complex process that occurs in various neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, and Huntington’s disease. Acid-sensing ion channels (ASICs) represent a widely expressed pH sensor in the brain that play a key role in neuroinflammation. On this basis, acid-sensing ion channel blockers are able to exert neuroprotective effects in different neurodegenerative diseases. In this review, we discuss the multifaceted roles of ASICs in brain physiology and pathology and highlight ASIC1a as a potential pharmacological target in neurodegenerative diseases.
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Affiliation(s)
- Dalila Mango
- Laboratory of Pharmacology of Synaptic Plasticity, European Brain Research Institute, Rome, Italy.,School of Pharmacy, University of Rome "Tor Vergata", Rome, Italy
| | - Robert Nisticò
- Laboratory of Pharmacology of Synaptic Plasticity, European Brain Research Institute, Rome, Italy.,School of Pharmacy, University of Rome "Tor Vergata", Rome, Italy
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14
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King P, Wan J, Guo AA, Guo S, Jiang Y, Liu M. Regulation of gliomagenesis and stemness through acid sensor ASIC1a. Int J Oncol 2021; 59:82. [PMID: 34515325 PMCID: PMC8448544 DOI: 10.3892/ijo.2021.5262] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 07/28/2021] [Indexed: 01/29/2023] Open
Abstract
Glioblastoma multiforme (GBM) is the most prevalent and aggressive type of adult gliomas. Despite intensive therapy including surgery, radiation, and chemotherapy, invariable tumor recurrence occurs, which suggests that glioblastoma stem cells (GSCs) render these tumors persistent. Recently, the induction of GSC differentiation has emerged as an alternative method to treat GBM, and most of the current studies aim to convert GSCs to neurons by a combination of transcriptional factors. As the tumor microenvironment is typically acidic due to increased glycolysis and consequently leads to an increased production of lactic acid in tumor cells, in the present study, the role of acid‑sensing ion channel 1a (ASIC1a), an acid sensor, was explored as a tumor suppressor in gliomagenesis and stemness. The bioinformatics data from The Cancer Genome Atlas revealed that ASIC1 expression levels in GBM tumor tissues were lower than those in normal brain, and glioma patients with high ASIC1 expression had longer survival than those with low ASIC1 expression. Our immunohistochemistry data from tissue microarray revealed that ASIC1a expression was negatively associated with glioma grading. Functional studies revealed that the downregulation of ASIC1a promoted glioma cell proliferation and invasion, while upregulation of ASIC1a inhibited their proliferation and invasion. Furthermore, ASIC1a suppressed growth and proliferation of glioma cells through G1/S arrest and apoptosis induction. Mechanistically, ASIC1a negatively modulated glioma stemness via inhibition of the Notch signaling pathway and GSC markers CD133 and aldehyde dehydrogenase 1. ASIC1a is a tumor suppressor in gliomagenesis and stemness and may serve as a promising prognostic biomarker and target for GBM patients.
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Affiliation(s)
- Pendelton King
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Jingwei Wan
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA 30310, USA
- Department of Neurosurgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Alyssa Aihui Guo
- Department of Biomedical Sciences, School of Medicine Greenville, University of South Carolina, Greenville, SC 29605, USA
| | - Shanchun Guo
- Department of Chemistry, Xavier University, New Orleans, LA 70125, USA
| | - Yugang Jiang
- Department of Neurosurgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Mingli Liu
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA 30310, USA
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15
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Acid-Sensing Ion Channels in Zebrafish. Animals (Basel) 2021; 11:ani11082471. [PMID: 34438928 PMCID: PMC8388743 DOI: 10.3390/ani11082471] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/20/2021] [Accepted: 08/21/2021] [Indexed: 12/13/2022] Open
Abstract
Simple Summary The present review collects data regarding the presence of ASICs (acid-sensing ion channels) in zebrafish, which have become, over several years, an important experimental model for the study of various diseases. ASICs are a family of ion channels involved in the perception of different types of stimuli. They are excitatory receptors for extracellular H+ involved in synaptic transmission, the peripheral perception of pain and in chemical or mechanosensation. Abstract The ASICs, in mammals as in fish, control deviations from the physiological values of extracellular pH, and are involved in mechanoreception, nociception, or taste receptions. They are widely expressed in the central and peripheral nervous system. In this review, we summarized the data about the presence and localization of ASICs in different organs of zebrafish that represent one of the most used experimental models for the study of several diseases. In particular, we analyzed the data obtained by immunohistochemical and molecular biology techniques concerning the presence and expression of ASICs in the sensory organs, such as the olfactory rosette, lateral line, inner ear, taste buds, and in the gut and brain of zebrafish.
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16
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Di Pompo G, Cortini M, Baldini N, Avnet S. Acid Microenvironment in Bone Sarcomas. Cancers (Basel) 2021; 13:cancers13153848. [PMID: 34359749 PMCID: PMC8345667 DOI: 10.3390/cancers13153848] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/24/2021] [Accepted: 07/28/2021] [Indexed: 12/15/2022] Open
Abstract
Simple Summary Although rare, malignant bone sarcomas have devastating clinical implications for the health and survival of young adults and children. To date, efforts to identify the molecular drivers and targets have focused on cancer cells or on the interplay between cancer cells and stromal cells in the tumour microenvironment. On the contrary, in the current literature, the role of the chemical-physical conditions of the tumour microenvironment that may be implicated in sarcoma aggressiveness and progression are poorly reported and discussed. Among these, extracellular acidosis is a well-recognized hallmark of bone sarcomas and promotes cancer growth and dissemination but data presented on this topic are fragmented. Hence, we intended to provide a general and comprehensive overview of the causes and implications of acidosis in bone sarcoma. Abstract In bone sarcomas, extracellular proton accumulation is an intrinsic driver of malignancy. Extracellular acidosis increases stemness, invasion, angiogenesis, metastasis, and resistance to therapy of cancer cells. It reprograms tumour-associated stroma into a protumour phenotype through the release of inflammatory cytokines. It affects bone homeostasis, as extracellular proton accumulation is perceived by acid-sensing ion channels located at the cell membrane of normal bone cells. In bone, acidosis results from the altered glycolytic metabolism of bone cancer cells and the resorption activity of tumour-induced osteoclasts that share the same ecosystem. Proton extrusion activity is mediated by extruders and transporters located at the cell membrane of normal and transformed cells, including vacuolar ATPase and carbonic anhydrase IX, or by the release of highly acidic lysosomes by exocytosis. To date, a number of investigations have focused on the effects of acidosis and its inhibition in bone sarcomas, including studies evaluating the use of photodynamic therapy. In this review, we will discuss the current status of all findings on extracellular acidosis in bone sarcomas, with a specific focus on the characteristics of the bone microenvironment and the acid-targeting therapeutic approaches that are currently being evaluated.
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Affiliation(s)
- Gemma Di Pompo
- Biomedical Science and Technologies Lab, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (G.D.P.); (M.C.); (N.B.)
| | - Margherita Cortini
- Biomedical Science and Technologies Lab, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (G.D.P.); (M.C.); (N.B.)
| | - Nicola Baldini
- Biomedical Science and Technologies Lab, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (G.D.P.); (M.C.); (N.B.)
- Department of Biomedical and Neuromotor Sciences, University of Bologna, 40126 Bologna, Italy
| | - Sofia Avnet
- Department of Biomedical and Neuromotor Sciences, University of Bologna, 40126 Bologna, Italy
- Correspondence:
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17
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Peng Y, Zhang Y, Zhang Y, Wang X, Xia Y. Pterostilbene alleviates pulmonary fibrosis by regulating ASIC2. Chin Med 2021; 16:66. [PMID: 34321072 PMCID: PMC8317282 DOI: 10.1186/s13020-021-00474-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 07/19/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Idiopathic pulmonary fibrosis (IPF) is a serious chronic disease of the respiratory system, but its current treatment has certain shortcomings and adverse effects. In this study, we evaluate the antifibrotic activity of pterostilbene (PTE) using an in vitro IPF model induced by transforming growth factor (TGF)-β1. METHODS A549 and alveolar epithelial cells (AECs) were incubated with 10 ng/ml TGF-β1 to induce lung fibroblast activation. Then, 30 μmol/L of PTE was used to treat these cells. The epithelial-mesenchymal transition (EMT), extracellular matrix (ECM) accumulation, and autophagy in cells were evaluated by western blot. Apoptosis was validated by flow cytometry analysis and western blot. Transcriptome high-throughput sequencing was performed on A549 cells incubated with TGF-β1 alone or TGF-β1 and PTE (TGF-β1 + PTE), and differentially expressed genes in PTE-treated cells were identified. The acid sensing ion channel subunit 2 (ASIC2) overexpression plasmid was used to rescue the protein levels of ASIC2 in A549 and AECs. RESULTS TGF-β1 caused EMT and ECM accumulation, and blocked the autophagy and apoptosis of A549 and AECs. Most importantly, 30 μmol/L of PTE inhibited pulmonary fibrosis induced by TGF-β1. Compared with TGF-β1, PTE inhibited EMT and ECM accumulation and rescued cell apoptosis and autophagy. The results of transcriptome high-throughput sequencing revealed that PTE greatly reduced the protein level of ASIC2. Compared with the TGF-β1 + PTE group, the transfection of ASIC2 overexpression plasmid stimulated the EMT and ECM accumulation and inhibited apoptosis and autophagy, suggesting that PTE inhibited pulmonary fibrosis by downregulating ASIC2. CONCLUSIONS This study suggests that PTE and ASIC2 inhibitors may have potential as IPF treatments in the future.
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Affiliation(s)
- Yanfang Peng
- Department of Traditional Chinese Medicine, Zhongnan Hospital of Wuhan University, No. 169 Donghu Road, Wuchang District, Wuhan, 430071, Hubei, China
| | - Yingwen Zhang
- Department of Traditional Chinese Medicine, Zhongnan Hospital of Wuhan University, No. 169 Donghu Road, Wuchang District, Wuhan, 430071, Hubei, China.
| | - Yabing Zhang
- Department of Traditional Chinese Medicine, Zhongnan Hospital of Wuhan University, No. 169 Donghu Road, Wuchang District, Wuhan, 430071, Hubei, China
| | - Xiuping Wang
- Department of Traditional Chinese Medicine, Zhongnan Hospital of Wuhan University, No. 169 Donghu Road, Wuchang District, Wuhan, 430071, Hubei, China
| | - Yukun Xia
- Department of Traditional Chinese Medicine, Zhongnan Hospital of Wuhan University, No. 169 Donghu Road, Wuchang District, Wuhan, 430071, Hubei, China
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18
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Expression Profiles of ASIC1/2 and TRPV1/4 in Common Skin Tumors. Int J Mol Sci 2021; 22:ijms22116024. [PMID: 34199609 PMCID: PMC8199644 DOI: 10.3390/ijms22116024] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 05/26/2021] [Accepted: 05/28/2021] [Indexed: 12/27/2022] Open
Abstract
The acid-sensing ion channels ASIC1 and ASIC2, as well as the transient receptor potential vanilloid channels TRPV1 and TRPV4, are proton-gated cation channels that can be activated by low extracellular pH (pHe), which is a hallmark of the tumor microenvironment in solid tumors. However, the role of these channels in the development of skin tumors is still unclear. In this study, we investigated the expression profiles of ASIC1, ASIC2, TRPV1 and TRPV4 in malignant melanoma (MM), squamous cell carcinoma (SCC), basal cell carcinoma (BCC) and in nevus cell nevi (NCN). We conducted immunohistochemistry using paraffin-embedded tissue samples from patients and found that most skin tumors express ASIC1/2 and TRPV1/4. Striking results were that BCCs are often negative for ASIC2, while nearly all SCCs express this marker. Epidermal MM sometimes seem to lack ASIC1 in contrast to NCN. Dermal portions of MM show strong expression of TRPV1 more frequently than dermal NCN portions. Some NCN show a decreasing ASIC1/2 expression in deeper dermal tumor tissue, while MM seem to not lose ASIC1/2 in deeper dermal portions. ASIC1, ASIC2, TRPV1 and TRPV4 in skin tumors might be involved in tumor progression, thus being potential diagnostic and therapeutic targets.
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19
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Zhu Y, Warrenfelt CIC, Flannery JC, Lindgren CA. Extracellular Protons Mediate Presynaptic Homeostatic Potentiation at the Mouse Neuromuscular Junction. Neuroscience 2021; 467:188-200. [PMID: 34215419 DOI: 10.1016/j.neuroscience.2021.01.036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 01/22/2021] [Accepted: 01/28/2021] [Indexed: 01/27/2023]
Abstract
At the vertebrate neuromuscular junction (NMJ), presynaptic homeostatic potentiation (PHP) refers to the upregulation of neurotransmitter release via an increase in quantal content (QC) when the postsynaptic nicotinic acetylcholine receptors (nAChRs) are partially blocked. The mechanism of PHP has not been completely worked out. In particular, the identity of the presumed retrograde signal is still a mystery. We investigated the role of acid-sensing ion channels (ASICs) and extracellular protons in mediating PHP at the mouse NMJ. We found that blocking AISCs using benzamil, psalmotoxin-1 (PcTx1), or mambalgin-3 (Mamb3) prevented PHP. Likewise, extracellular acidification from pH 7.4 to 7.2 triggered a significant, reversable increase in QC and this increase could be prevented by PcTx1. Interestingly, an acidic saline (pH 7.2) also precluded the subsequent induction of PHP. Using immunofluorescence we observed ASIC2a and ASIC1 subunits at the NMJ. Our results indicate that protons and ASIC channels are involved in activating PHP at the mouse NMJ. We speculate that the partial blockade of nAChRs leads to a modest decrease in the pH of the synaptic cleft (∼0.2 pH units) and this activates ASIC channels on the presynaptic nerve terminal.
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Affiliation(s)
- Yiyang Zhu
- Department of Biology, Grinnell College, Grinnell, IA 50112, USA
| | | | - Jill C Flannery
- Department of Biology, Grinnell College, Grinnell, IA 50112, USA
| | - Clark A Lindgren
- Department of Biology, Grinnell College, Grinnell, IA 50112, USA.
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20
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ASIC1 and ASIC3 mediate cellular senescence of human nucleus pulposus mesenchymal stem cells during intervertebral disc degeneration. Aging (Albany NY) 2021; 13:10703-10723. [PMID: 33824228 PMCID: PMC8064223 DOI: 10.18632/aging.202850] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 02/16/2021] [Indexed: 12/22/2022]
Abstract
Stem cell approaches have become an attractive therapeutic option for intervertebral disc degeneration (IVDD). Nucleus pulposus mesenchymal stem cells (NP-MSCs) participate in the regeneration and homeostasis of the intervertebral disc (IVD), but the molecular mechanisms governing these processes remain to be elucidated. Acid-sensing ion channels (ASICs) which act as key receptors for extracellular protons in central and peripheral neurons, have been implicated in IVDD where degeneration is associated with reduced microenvironmental pH. Here we show that ASIC1 and ASIC3, but not ASIC2 and ASIC4 are upregulated in human IVDs according to the degree of clinical degeneration. Subjecting IVD-derived NP-MSCs to pH 6.6 culture conditions to mimic pathological IVD changes resulted in decreased cell proliferation that was associated with cell cycle arrest and induction of senescence. Key molecular changes observed were increased expression of p53, p21, p27, p16 and Rb1. Instructively, premature senescence in NP-MSCs could be largely alleviated using ASIC inhibitors, suggesting both ASIC1 and ASIC3 act decisively upstream to activate senescence programming pathways including p53-p21/p27 and p16-Rb1 signaling. These results highlight the potential of ASIC inhibitors as a therapeutic approach for IVDD and broadly define an in vitro system that can be used to evaluate other IVDD therapies.
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21
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Molecular mechanism and structural basis of small-molecule modulation of the gating of acid-sensing ion channel 1. Commun Biol 2021; 4:174. [PMID: 33564124 PMCID: PMC7873226 DOI: 10.1038/s42003-021-01678-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 01/07/2021] [Indexed: 01/07/2023] Open
Abstract
Acid-sensing ion channels (ASICs) are proton-gated cation channels critical for neuronal functions. Studies of ASIC1, a major ASIC isoform and proton sensor, have identified acidic pocket, an extracellular region enriched in acidic residues, as a key participant in channel gating. While binding to this region by the venom peptide psalmotoxin modulates channel gating, molecular and structural mechanisms of ASIC gating modulation by small molecules are poorly understood. Here, combining functional, crystallographic, computational and mutational approaches, we show that two structurally distinct small molecules potently and allosterically inhibit channel activation and desensitization by binding at the acidic pocket and stabilizing the closed state of rat/chicken ASIC1. Our work identifies a previously unidentified binding site, elucidates a molecular mechanism of small molecule modulation of ASIC gating, and demonstrates directly the structural basis of such modulation, providing mechanistic and structural insight into ASIC gating, modulation and therapeutic targeting.
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22
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Hariharan A, Weir N, Robertson C, He L, Betsholtz C, Longden TA. The Ion Channel and GPCR Toolkit of Brain Capillary Pericytes. Front Cell Neurosci 2020; 14:601324. [PMID: 33390906 PMCID: PMC7775489 DOI: 10.3389/fncel.2020.601324] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/13/2020] [Indexed: 12/14/2022] Open
Abstract
Brain pericytes reside on the abluminal surface of capillaries, and their processes cover ~90% of the length of the capillary bed. These cells were first described almost 150 years ago (Eberth, 1871; Rouget, 1873) and have been the subject of intense experimental scrutiny in recent years, but their physiological roles remain uncertain and little is known of the complement of signaling elements that they employ to carry out their functions. In this review, we synthesize functional data with single-cell RNAseq screens to explore the ion channel and G protein-coupled receptor (GPCR) toolkit of mesh and thin-strand pericytes of the brain, with the aim of providing a framework for deeper explorations of the molecular mechanisms that govern pericyte physiology. We argue that their complement of channels and receptors ideally positions capillary pericytes to play a central role in adapting blood flow to meet the challenge of satisfying neuronal energy requirements from deep within the capillary bed, by enabling dynamic regulation of their membrane potential to influence the electrical output of the cell. In particular, we outline how genetic and functional evidence suggest an important role for Gs-coupled GPCRs and ATP-sensitive potassium (KATP) channels in this context. We put forth a predictive model for long-range hyperpolarizing electrical signaling from pericytes to upstream arterioles, and detail the TRP and Ca2+ channels and Gq, Gi/o, and G12/13 signaling processes that counterbalance this. We underscore critical questions that need to be addressed to further advance our understanding of the signaling topology of capillary pericytes, and how this contributes to their physiological roles and their dysfunction in disease.
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Affiliation(s)
- Ashwini Hariharan
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Nick Weir
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Colin Robertson
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Liqun He
- Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Christer Betsholtz
- Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.,Department of Medicine Huddinge (MedH), Karolinska Institutet & Integrated Cardio Metabolic Centre, Huddinge, Sweden
| | - Thomas A Longden
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
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23
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Yan S, Resta TC, Jernigan NL. Vasoconstrictor Mechanisms in Chronic Hypoxia-Induced Pulmonary Hypertension: Role of Oxidant Signaling. Antioxidants (Basel) 2020; 9:E999. [PMID: 33076504 PMCID: PMC7602539 DOI: 10.3390/antiox9100999] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 10/06/2020] [Accepted: 10/06/2020] [Indexed: 02/06/2023] Open
Abstract
Elevated resistance of pulmonary circulation after chronic hypoxia exposure leads to pulmonary hypertension. Contributing to this pathological process is enhanced pulmonary vasoconstriction through both calcium-dependent and calcium sensitization mechanisms. Reactive oxygen species (ROS), as a result of increased enzymatic production and/or decreased scavenging, participate in augmentation of pulmonary arterial constriction by potentiating calcium influx as well as activation of myofilament sensitization, therefore mediating the development of pulmonary hypertension. Here, we review the effects of chronic hypoxia on sources of ROS within the pulmonary vasculature including NADPH oxidases, mitochondria, uncoupled endothelial nitric oxide synthase, xanthine oxidase, monoamine oxidases and dysfunctional superoxide dismutases. We also summarize the ROS-induced functional alterations of various Ca2+ and K+ channels involved in regulating Ca2+ influx, and of Rho kinase that is responsible for myofilament Ca2+ sensitivity. A variety of antioxidants have been shown to have beneficial therapeutic effects in animal models of pulmonary hypertension, supporting the role of ROS in the development of pulmonary hypertension. A better understanding of the mechanisms by which ROS enhance vasoconstriction will be useful in evaluating the efficacy of antioxidants for the treatment of pulmonary hypertension.
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Affiliation(s)
| | | | - Nikki L. Jernigan
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA; (S.Y.); (T.C.R.)
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Drug development in targeting ion channels for brain edema. Acta Pharmacol Sin 2020; 41:1272-1288. [PMID: 32855530 PMCID: PMC7609292 DOI: 10.1038/s41401-020-00503-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 08/02/2020] [Indexed: 12/18/2022] Open
Abstract
Cerebral edema is a pathological hallmark of various central nervous system (CNS) insults, including traumatic brain injury (TBI) and excitotoxic injury such as stroke. Due to the rigidity of the skull, edema-induced increase of intracranial fluid significantly complicates severe CNS injuries by raising intracranial pressure and compromising perfusion. Mortality due to cerebral edema is high. With mortality rates up to 80% in severe cases of stroke, it is the leading cause of death within the first week. Similarly, cerebral edema is devastating for patients of TBI, accounting for up to 50% mortality. Currently, the available treatments for cerebral edema include hypothermia, osmotherapy, and surgery. However, these treatments only address the symptoms and often elicit adverse side effects, potentially in part due to non-specificity. There is an urgent need to identify effective pharmacological treatments for cerebral edema. Currently, ion channels represent the third-largest target class for drug development, but their roles in cerebral edema remain ill-defined. The present review aims to provide an overview of the proposed roles of ion channels and transporters (including aquaporins, SUR1-TRPM4, chloride channels, glucose transporters, and proton-sensitive channels) in mediating cerebral edema in acute ischemic stroke and TBI. We also focus on the pharmacological inhibitors for each target and potential therapeutic strategies that may be further pursued for the treatment of cerebral edema.
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ASIC1a activation induces calcium-dependent apoptosis of BMSCs under conditions that mimic the acidic microenvironment of the degenerated intervertebral disc. Biosci Rep 2020; 39:220895. [PMID: 31696219 PMCID: PMC6851507 DOI: 10.1042/bsr20192708] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 10/03/2019] [Accepted: 10/18/2019] [Indexed: 12/22/2022] Open
Abstract
Purpose: In the degenerated intervertebral disc (IVD), matrix acidity challenges transplanted bone marrow mesenchymal stem cells (BMSCs). The Ca2+-permeable acid-sensing ion channel 1a (ASIC1a) is responsible for acidosis-mediated tissue injury. The aim of our study was to confirm whether ASIC1a activation induces BMSC apoptosis under conditions that mimic the acidic microenvironment of the degenerated IVD. Methods: ASIC1a expression in rat BMSCs was investigated by real time-PCR, Western blot (WB) and immunofluorescence. The proliferation and apoptosis of BMSCs under acidic conditions were analyzed by MTT and TUNEL assays. Ca2+-imaging was used to assess the acid-induced increase in the intracellular Ca2+ concentration ([Ca2+]i). The activation of calpain and calcineurin was analyzed using specific kits, and WB analysis was performed to detect apoptosis-related proteins. Ultrastructural changes in BMSCs were observed using transmission electron microscopy (TEM). Results: Acid exposure led to the activation of ASIC1a and increased BMSC apoptosis. The Ca2+ imaging assay showed a significant increase in the [Ca2+]i in response to a solution at pH 6.0. However, BMSC apoptosis and [Ca2+]i elevation were alleviated in the presence of an ASIC1a inhibitor. Moreover, ASIC1a mediated the Ca2+ influx-induced activation of calpain and calcineurin in BMSCs. WB analysis and TEM revealed mitochondrial apoptosis, which was inhibited by an ASIC1a inhibitor, in BMSCs under acidic conditions. Conclusions: The mimical acidic microenvironment of the degenerated IVD can induce BMSC apoptosis by activating Ca2+-permeable ASIC1a. An acid-induced elevation of [Ca2+]i in BMSCs leads to the subsequent activation of calpain and calcineurin, further resulting in increased mitochondrial permeability and mitochondrial-mediated apoptosis.
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Liu X, Sambath K, Hutnik L, Du J, Belfield KD, Zhang Y. Activating Acid‐Sensing Ion Channels with Photoacid Generators. CHEMPHOTOCHEM 2020; 4:5337-5340. [DOI: 10.1002/cptc.202000154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Xinglei Liu
- Department of Chemistry and Environmental Science College of Science and Liberal Arts New Jersey Institute of Technology 323 Martin Luther King, Jr. Blvd. Newark NJ 07102 USA
| | - Karthik Sambath
- Department of Chemistry and Environmental Science College of Science and Liberal Arts New Jersey Institute of Technology 323 Martin Luther King, Jr. Blvd. Newark NJ 07102 USA
| | - Lauren Hutnik
- Department of Chemistry and Environmental Science College of Science and Liberal Arts New Jersey Institute of Technology 323 Martin Luther King, Jr. Blvd. Newark NJ 07102 USA
| | - Jianyang Du
- Department of Anatomy and Neurobiology The University of Tennessee Health Science Center 855 Monroe Avenue Memphis TN 38163 USA
| | - Kevin D. Belfield
- Department of Chemistry and Environmental Science College of Science and Liberal Arts New Jersey Institute of Technology 323 Martin Luther King, Jr. Blvd. Newark NJ 07102 USA
| | - Yuanwei Zhang
- Department of Chemistry and Environmental Science College of Science and Liberal Arts New Jersey Institute of Technology 323 Martin Luther King, Jr. Blvd. Newark NJ 07102 USA
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Pethő Z, Najder K, Carvalho T, McMorrow R, Todesca LM, Rugi M, Bulk E, Chan A, Löwik CWGM, Reshkin SJ, Schwab A. pH-Channeling in Cancer: How pH-Dependence of Cation Channels Shapes Cancer Pathophysiology. Cancers (Basel) 2020; 12:E2484. [PMID: 32887220 PMCID: PMC7565548 DOI: 10.3390/cancers12092484] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 12/20/2022] Open
Abstract
Tissue acidosis plays a pivotal role in tumor progression: in particular, interstitial acidosis promotes tumor cell invasion, and is a major contributor to the dysregulation of tumor immunity and tumor stromal cells. The cell membrane and integral membrane proteins commonly act as important sensors and transducers of altered pH. Cell adhesion molecules and cation channels are prominent membrane proteins, the majority of which is regulated by protons. The pathophysiological consequences of proton-sensitive ion channel function in cancer, however, are scarcely considered in the literature. Thus, the main focus of this review is to highlight possible events in tumor progression and tumor immunity where the pH sensitivity of cation channels could be of great importance.
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Affiliation(s)
- Zoltán Pethő
- Institute of Physiology II, University Münster, 48147 Münster, Germany; (K.N.); (L.M.T.); (M.R.); (E.B.); (A.S.)
| | - Karolina Najder
- Institute of Physiology II, University Münster, 48147 Münster, Germany; (K.N.); (L.M.T.); (M.R.); (E.B.); (A.S.)
| | - Tiago Carvalho
- Department of Biosciences, Biotechnologies, and Biopharmaceutics, University of Bari, 90126 Bari, Italy; (T.C.); (S.J.R.)
| | - Roisin McMorrow
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, 3035 GD Rotterdam, The Netherlands; (R.M.); (C.W.G.M.L.)
| | - Luca Matteo Todesca
- Institute of Physiology II, University Münster, 48147 Münster, Germany; (K.N.); (L.M.T.); (M.R.); (E.B.); (A.S.)
| | - Micol Rugi
- Institute of Physiology II, University Münster, 48147 Münster, Germany; (K.N.); (L.M.T.); (M.R.); (E.B.); (A.S.)
| | - Etmar Bulk
- Institute of Physiology II, University Münster, 48147 Münster, Germany; (K.N.); (L.M.T.); (M.R.); (E.B.); (A.S.)
| | - Alan Chan
- Percuros B.V., 2333 CL Leiden, The Netherlands;
| | - Clemens W. G. M. Löwik
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, 3035 GD Rotterdam, The Netherlands; (R.M.); (C.W.G.M.L.)
- Department of Oncology CHUV, UNIL and Ludwig Cancer Center, 1011 Lausanne, Switzerland
| | - Stephan J. Reshkin
- Department of Biosciences, Biotechnologies, and Biopharmaceutics, University of Bari, 90126 Bari, Italy; (T.C.); (S.J.R.)
| | - Albrecht Schwab
- Institute of Physiology II, University Münster, 48147 Münster, Germany; (K.N.); (L.M.T.); (M.R.); (E.B.); (A.S.)
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Peripheral Mechanobiology of Touch-Studies on Vertebrate Cutaneous Sensory Corpuscles. Int J Mol Sci 2020; 21:ijms21176221. [PMID: 32867400 PMCID: PMC7504094 DOI: 10.3390/ijms21176221] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 08/19/2020] [Accepted: 08/24/2020] [Indexed: 12/21/2022] Open
Abstract
The vertebrate skin contains sensory corpuscles that are receptors for different qualities of mechanosensitivity like light brush, touch, pressure, stretch or vibration. These specialized sensory organs are linked anatomically and functionally to mechanosensory neurons, which function as low-threshold mechanoreceptors connected to peripheral skin through Aβ nerve fibers. Furthermore, low-threshold mechanoreceptors associated with Aδ and C nerve fibers have been identified in hairy skin. The process of mechanotransduction requires the conversion of a mechanical stimulus into electrical signals (action potentials) through the activation of mechanosensible ion channels present both in the axon and the periaxonal cells of sensory corpuscles (i.e., Schwann-, endoneurial- and perineurial-related cells). Most of those putative ion channels belong to the degenerin/epithelial sodium channel (especially the family of acid-sensing ion channels), the transient receptor potential channel superfamilies, and the Piezo family. This review updates the current data about the occurrence and distribution of putative mechanosensitive ion channels in cutaneous mechanoreceptors including primary sensory neurons and sensory corpuscles.
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Varfolomeev SD, Bykov VI, Tsybenova SB. Kinetic modeling of dynamic processes in the cholinergic synapse. Russ Chem Bull 2020. [DOI: 10.1007/s11172-020-2939-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Campos MO, Mansur DE, Mattos JD, Paiva ACS, Videira RLR, Macefield VG, da Nóbrega ACL, Fernandes IA. Acid-sensing ion channels blockade attenuates pressor and sympathetic responses to skeletal muscle metaboreflex activation in humans. J Appl Physiol (1985) 2019; 127:1491-1501. [PMID: 31545154 DOI: 10.1152/japplphysiol.00401.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
In animals, the blockade of acid-sensing ion channels (ASICs), cation pore-forming membrane proteins located in the free nerve endings of group IV afferent fibers, attenuates increases in arterial pressure (AP) and sympathetic nerve activity (SNA) during muscle contraction. Therefore, ASICs play a role in mediating the metabolic component (skeletal muscle metaboreflex) of the exercise pressor reflex in animal models. Here we tested the hypothesis that ASICs also play a role in evoking the skeletal muscle metaboreflex in humans, quantifying beat-by-beat mean AP (MAP; finger photoplethysmography) and muscle SNA (MSNA; microneurography) in 11 men at rest and during static handgrip exercise (SHG; 35% of the maximal voluntary contraction) and postexercise muscle ischemia (PEMI) before (B) and after (A) local venous infusion of either saline or amiloride (AM), an ASIC antagonist, via the Bier block technique. MAP (BAM +30 ± 6 vs. AAM +25 ± 7 mmHg, P = 0.001) and MSNA (BAM +14 ± 9 vs. AAM +10 ± 6 bursts/min, P = 0.004) responses to SHG were attenuated under ASIC blockade. Amiloride also attenuated the PEMI-induced increases in MAP (BAM +25 ± 6 vs. AAM +16 ± 6 mmHg, P = 0.0001) and MSNA (BAM +16 ± 9 vs. AAM +8 ± 8 bursts/min, P = 0.0001). MAP and MSNA responses to SHG and PEMI were similar before and after saline infusion. We conclude that ASICs play a role in evoking pressor and sympathetic responses to SHG and the isolated activation of the skeletal muscle metaboreflex in humans. NEW & NOTEWORTHY We showed that regional blockade of the acid-sensing ion channels (ASICs), induced by venous infusion of the antagonist amiloride via the Bier block anesthetic technique, attenuated increases in arterial pressure and muscle sympathetic nerve activity during both static handgrip exercise and postexercise muscle ischemia. These findings indicate that ASICs contribute to both pressor and sympathetic responses to the activation of the skeletal muscle metaboreflex in humans.
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Affiliation(s)
- Monique O Campos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Daniel E Mansur
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - João D Mattos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Adrielle C S Paiva
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | | | - Vaughan G Macefield
- School of Medicine, Western Sydney University, Sydney, Australia.,Baker Heart and Diabetes Institute, Melbourne, Australia
| | | | - Igor A Fernandes
- NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Brazil
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Shear force modulates the activity of acid-sensing ion channels at low pH or in the presence of non-proton ligands. Sci Rep 2019; 9:6781. [PMID: 31043630 PMCID: PMC6494901 DOI: 10.1038/s41598-019-43097-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 04/16/2019] [Indexed: 12/17/2022] Open
Abstract
Acid-sensing ion channels (ASICs) belong to the degenerin/epithelial sodium channel protein family that form mechanosensitive ion channels. Evidence as to whether or not ASICs activity is directly modulated by mechanical force is lacking. Human ASICs (hASIC1V3, hASIC2a and hASIC3a) were heterologously expressed as homomeric channels in Xenopus oocytes and two-electrode voltage-clamp recordings were performed. hASIC3a was expressed in HEK-293 cells and currents measured by whole-cell patch-clamp recordings. ASIC currents in response to shear force (SF) were measured at pH 7.4, acidic pH, or in the presence of non-proton ligands at pH 7.4. SF was applied via a fluid stream generated through a pressurized perfusion system. No effect was observed at pH 7.4. Increased transient currents for each homomeric channel were observed when elevated SF was applied in conjunction with acidic pH (6.0-4.0). The sustained current was not (hASIC2a) or only slightly increased (hASIC1V3 and hASIC3a). SF-induced effects were not seen in water injected oocytes and were blocked by amiloride. Non-proton ligands activated a persistent current in hASIC1V3 and cASIC1 (MitTx) and hASIC3a (GMQ) at pH 7.4. Here SF caused a further current increase. Results suggest that ASICs do have an intrinsic ability to respond to mechanical force, supporting their role as mechanosensors in certain local environments.
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Zaremba M, Ruiz-Velasco V. Opioid-Mediated Modulation of Acid-Sensing Ion Channel Currents in Adult Rat Sensory Neurons. Mol Pharmacol 2019; 95:519-527. [PMID: 30808671 DOI: 10.1124/mol.118.114918] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 02/20/2019] [Indexed: 01/10/2023] Open
Abstract
Muscle ischemia, associated with peripheral artery disease (PAD), leads to the release of proinflammatory mediators that decrease extracellular pH and trigger the activation of proton-activated acid-sensing ion channels (ASIC). Claudication pain, linked with low blood flow, can be partially relieved by endogenous opioid peptide release. However, we previously reported that sustained ASIC currents in dorsal root ganglion (DRG) neurons were enhanced by naturally occurring endomorphin-1 and -2 opioid peptides, indicating a role of opioid involvement in hyperalgesia. The present study examined whether clinically employed synthetic (fentanyl, remifentanil) and the semisynthetic opioid (oxycodone) would also potentiate sustained ASIC currents, which arise from ASIC3 channel isoforms. Here, we show that exposure of each opioid to DRG neurons resulted in potentiation of the sustained ASIC currents. On the other hand, the potentiation was not observed in DRG neurons from ASIC3 knockout rats. Further, the enhancement of the ASIC currents was resistant to pertussis toxin treatment, suggesting that Gα i/Gα o G-proteins are not involved. Additionally, the potentiation of sustained ASIC currents was greater in DRG neurons isolated from rats with ligated femoral arteries (a model of PAD). The effect of all three opioids on the transient ASIC peak current was mixed (increase, decrease, no effect). The inhibitory action appears to be mediated by the presence of ASIC1 isoform, while the potentiating effect is primarily due to ASIC3 isoform expression. These findings reveal that, under certain conditions, these three opioids can increase ASIC channel activity, possibly giving rise to opioid-induced hyperalgesia.
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Affiliation(s)
- Malgorzata Zaremba
- Ruiz-Velasco Laboratory, Department of Anesthesiology and Perioperative Medicine, Penn State College of Medicine, Hershey, Pennsylvania
| | - Victor Ruiz-Velasco
- Ruiz-Velasco Laboratory, Department of Anesthesiology and Perioperative Medicine, Penn State College of Medicine, Hershey, Pennsylvania
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Therapeutic Effect of Agmatine on Neurological Disease: Focus on Ion Channels and Receptors. Neurochem Res 2019; 44:735-750. [PMID: 30610652 DOI: 10.1007/s11064-018-02712-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/19/2018] [Accepted: 12/24/2018] [Indexed: 02/08/2023]
Abstract
The central nervous system (CNS) is the most injury-prone part of the mammalian body. Any acute or chronic, central or peripheral neurological disorder is related to abnormal biochemical and electrical signals in the brain cells. As a result, ion channels and receptors that are abundant in the nervous system and control the electrical and biochemical environment of the CNS play a vital role in neurological disease. The N-methyl-D-aspartate receptor, 2-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl) propanoic acid receptor, kainate receptor, acetylcholine receptor, serotonin receptor, α2-adrenoreceptor, and acid-sensing ion channels are among the major channels and receptors known to be key components of pathophysiological events in the CNS. The primary amine agmatine, a neuromodulator synthesized in the brain by decarboxylation of L-arginine, can regulate ion channel cascades and receptors that are related to the major CNS disorders. In our previous studies, we established that agmatine was related to the regulation of cell differentiation, nitric oxide synthesis, and murine brain endothelial cell migration, relief of chronic pain, cerebral edema, and apoptotic cell death in experimental CNS disorders. In this review, we will focus on the pathophysiological aspects of the neurological disorders regulated by these ion channels and receptors, and their interaction with agmatine in CNS injury.
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Abstract
It is now well established that antibodies have numerous potential benefits when developed as therapeutics. Here, we evaluate the technical challenges of raising antibodies to membrane-spanning proteins together with enabling technologies that may facilitate the discovery of antibody therapeutics to ion channels. Additionally, we discuss the potential targeting opportunities in the anti-ion channel antibody landscape, along with a number of case studies where functional antibodies that target ion channels have been reported. Antibodies currently in development and progressing towards the clinic are highlighted.
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Affiliation(s)
| | - Paul Colussi
- a TetraGenetics Inc , Arlington Massachusetts , USA
| | - Theodore G Clark
- a TetraGenetics Inc , Arlington Massachusetts , USA.,b Department of Microbiology and Immunology , Cornell University , Ithaca New York , USA
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Flinck M, Kramer SH, Pedersen SF. Roles of pH in control of cell proliferation. Acta Physiol (Oxf) 2018; 223:e13068. [PMID: 29575508 DOI: 10.1111/apha.13068] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 02/17/2018] [Accepted: 03/19/2018] [Indexed: 02/06/2023]
Abstract
Precise spatiotemporal regulation of intracellular pH (pHi ) is a prerequisite for normal cell function, and changes in pHi or pericellular pH (pHe ) exert important signalling functions. It is well established that proliferation of mammalian cells is dependent on a permissive pHi in the slightly alkaline range (7.0-7.2). It is also clear that mitogen signalling in nominal absence of HCO3- is associated with an intracellular alkalinization (~0.3 pH unit above steady-state pHi ), which is secondary to activation of Na+ /H+ exchange. However, it remains controversial whether this increase in pHi is part of the mitogenic signal cascade leading to cell cycle entry and progression, and whether it is relevant under physiological conditions. Furthermore, essentially all studies of pHi in mammalian cell proliferation have focused on the mitogen-induced G0-G1 transition, and the regulation and roles of pHi during the cell cycle remain poorly understood. The aim of this review is to summarize and critically discuss the possible roles of pHi and pHe in cell cycle progression. While the focus is on the mammalian cell cycle, important insights from studies in lower eukaryotes are also discussed. We summarize current evidence of links between cell cycle progression and pHi and discuss possible pHi - and pHe sensors and signalling pathways relevant to mammalian proliferation control. The possibility that changes in pHi during cell cycle progression may be an integral part of the checkpoint control machinery is explored. Finally, we discuss the relevance of links between pH and proliferation in the context of the perturbed pH homoeostasis and acidic microenvironment of solid tumours.
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Affiliation(s)
- M. Flinck
- Section for Cell Biology and Physiology; Department of Biology; Faculty of Science; University of Copenhagen; Copenhagen Denmark
| | - S. H. Kramer
- Section for Cell Biology and Physiology; Department of Biology; Faculty of Science; University of Copenhagen; Copenhagen Denmark
| | - S. F. Pedersen
- Section for Cell Biology and Physiology; Department of Biology; Faculty of Science; University of Copenhagen; Copenhagen Denmark
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Cryo-EM structure of the ASIC1a-mambalgin-1 complex reveals that the peptide toxin mambalgin-1 inhibits acid-sensing ion channels through an unusual allosteric effect. Cell Discov 2018; 4:27. [PMID: 29872539 PMCID: PMC5986765 DOI: 10.1038/s41421-018-0026-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 03/20/2018] [Accepted: 03/20/2018] [Indexed: 02/07/2023] Open
Abstract
Acid-sensing ion channels (ASICs) are neuronal voltage-independent Na+ channels that are activated by extracellular acidification. ASICs play essential roles in a wide range of physiological processes, including sodium homeostasis, synaptic plasticity, neurodegeneration, and sensory transduction. Mambalgins, a family of three-finger toxins isolated from black mamba venom, specifically inhibit ASICs to exert strong analgesic effects in vivo, thus are thought to have potential therapeutic values against pain. However, the interaction and inhibition mechanism of mambalgin on ASICs remains elusive. Here, we report a cryo-electron microscopy (cryo-EM) structure of chicken ASIC1a (cASIC1a) in complex with mambalgin-1 toxin at 5.4 Å resolution. Our structure provides the first experimental evidence that mambalgin-1 interacts directly with the extracellular thumb domain of cASIC1a, rather than inserting into the acid-sensing pocket, as previously reported. Binding of mambalgin-1 leads to relocation of the thumb domain that could disrupt the acidic pocket of cASIC1a, illustrating an unusual inhibition mechanism of toxins on ASIC channels through an allosteric effect. These findings establish a structural basis for the toxicity of the mambalgins, and provide crucial insights for the development of new optimized inhibitors of ASICs.
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Identification of a unique Ca 2+-binding site in rat acid-sensing ion channel 3. Nat Commun 2018; 9:2082. [PMID: 29802295 PMCID: PMC5970173 DOI: 10.1038/s41467-018-04424-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 04/17/2018] [Indexed: 12/20/2022] Open
Abstract
Acid-sensing ion channels (ASICs) evolved to sense changes in extracellular acidity with the divalent cation calcium (Ca2+) as an allosteric modulator and channel blocker. The channel-blocking activity is most apparent in ASIC3, as removing Ca2+ results in channel opening, with the site's location remaining unresolved. Here we show that a ring of rat ASIC3 (rASIC3) glutamates (Glu435), located above the channel gate, modulates proton sensitivity and contributes to the formation of the elusive Ca2+ block site. Mutation of this residue to glycine, the equivalent residue in chicken ASIC1, diminished the rASIC3 Ca2+ block effect. Atomistic molecular dynamic simulations corroborate the involvement of this acidic residue in forming a high-affinity Ca2+ site atop the channel pore. Furthermore, the reported observations provide clarity for past controversies regarding ASIC channel gating. Our findings enhance understanding of ASIC gating mechanisms and provide structural and energetic insights into this unique calcium-binding site.
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Kautz R, Ordinario DD, Tyagi V, Patel P, Nguyen TN, Gorodetsky AA. Cephalopod-Derived Biopolymers for Ionic and Protonic Transistors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1704917. [PMID: 29656448 DOI: 10.1002/adma.201704917] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Revised: 12/05/2017] [Indexed: 06/08/2023]
Abstract
Cephalopods (e.g., squid, octopuses, and cuttlefish) have long fascinated scientists and the general public alike due to their complex behavioral characteristics and remarkable camouflage abilities. As such, these animals are explored as model systems in neuroscience and represent a well-known commercial resource. Herein, selected literature examples related to the electrical properties of cephalopod-derived biopolymers (eumelanins, chitosans, and reflectins) and to the use of these materials in voltage-gated devices (i.e., transistors) are highlighted. Moreover, some potential future directions and challenges in this area are described, with the aim of inspiring additional research effort on ionic and protonic transistors from cephalopod-derived biopolymers.
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Affiliation(s)
- Rylan Kautz
- Department of Chemical Engineering and Materials Science, University of California, Irvine, Irvine, CA, 92697, USA
| | - David D Ordinario
- Department of Chemical Engineering and Materials Science, University of California, Irvine, Irvine, CA, 92697, USA
- Department of Electrical Engineering and Information Systems, Graduate School of Engineering, University of Tokyo, Tokyo, 113-8656, Japan
| | - Vivek Tyagi
- Department of Chemical Engineering and Materials Science, University of California, Irvine, Irvine, CA, 92697, USA
| | - Priyam Patel
- Department of Chemical Engineering and Materials Science, University of California, Irvine, Irvine, CA, 92697, USA
| | - Tam N Nguyen
- Department of Chemistry, University of California, Irvine, Irvine, CA, 92697, USA
| | - Alon A Gorodetsky
- Department of Chemical Engineering and Materials Science, University of California, Irvine, Irvine, CA, 92697, USA
- Department of Chemistry, University of California, Irvine, Irvine, CA, 92697, USA
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Drummond HA, Xiang L, Chade AR, Hester R. Enhanced maximal exercise capacity, vasodilation to electrical muscle contraction, and hind limb vascular density in ASIC1a null mice. Physiol Rep 2018; 5:5/15/e13368. [PMID: 28784852 PMCID: PMC5555894 DOI: 10.14814/phy2.13368] [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: 04/20/2017] [Revised: 06/27/2017] [Accepted: 06/28/2017] [Indexed: 12/15/2022] Open
Abstract
Acid‐sensing ion channel (ASIC) proteins form extracellular proton‐gated, cation‐selective channels in neurons and vascular smooth muscle cells and are proposed to act as extracellular proton sensors. However, their importance to vascular responses under conditions associated with extracellular acidosis, such as strenuous exercise, is unclear. Therefore, the purpose of this study was to determine if one ASIC protein, ASIC1a, contributes to extracellular proton‐gated vascular responses and exercise tolerance. To determine if ASIC1a contributes to exercise tolerance, we determined peak oxygen (O2) uptake in conscious ASIC1a−/− mice during exhaustive treadmill running. Loss of ASIC1a was associated with a greater peak running speed (60 ± 2 vs. 53 ± 3 m·min−1, P = 0.049) and peak oxygen (O2) uptake during exhaustive treadmill running (9563 ± 120 vs. 8836 ± 276 mL·kg−1·h−1, n = 6–7, P = 0.0082). There were no differences in absolute or relative lean body mass, as determined by EchoMRI. To determine if ASIC1a contributes to vascular responses during muscle contraction, we measured femoral vascular conductance (FVC) during a stepwise electrical stimulation (0.5–5.0 Hz at 3 V for 60 sec) of the left major hind limb muscles. FVC increased to a greater extent in ASIC1a−/− versus ASIC1a+/+ mice (0.44 ± 0.03 vs. 0.30 ± 0.04 mL·min−1·100 g hind limb mass−1 · mmHg−1, n = 5 each, P = 0.0009). Vasodilation following local application of external protons in the spinotrapezius muscle increased the duration, but not the magnitude, of the vasodilatory response in ASIC1a−/− mice. Finally, we examined hind limb vascular density using micro‐CT and found increased density of 0–80 μm vessels (P < 0.05). Our findings suggest an increased vascular density and an enhanced vasodilatory response to local protons, to a lesser degree, may contribute to the enhanced vascular conductance and increased peak exercise capacity in ASIC1a−/− mice.
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Affiliation(s)
- Heather A Drummond
- Department of Physiology and Biophysics and the Center for Excellence in Cardiovascular-Renal Research, University of Mississippi Medical Center, Jackson, Mississippi
| | - Lusha Xiang
- Department of Physiology and Biophysics and the Center for Excellence in Cardiovascular-Renal Research, University of Mississippi Medical Center, Jackson, Mississippi
| | - Alejandro R Chade
- Department of Physiology and Biophysics and the Center for Excellence in Cardiovascular-Renal Research, University of Mississippi Medical Center, Jackson, Mississippi
| | - Robert Hester
- Department of Physiology and Biophysics and the Center for Excellence in Cardiovascular-Renal Research, University of Mississippi Medical Center, Jackson, Mississippi
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40
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Zhou H, Wang ZS, Liu XH, Chen FH. Novel amidrazone derivatives: Design, synthesis and activity evaluation. Bioorg Med Chem 2018; 26:3158-3165. [PMID: 29699911 DOI: 10.1016/j.bmc.2018.04.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Revised: 04/18/2018] [Accepted: 04/19/2018] [Indexed: 10/17/2022]
Abstract
A series of new 6-styryl-naphthalene-2-amidrazone derivatives were synthesized and evaluated as potential ASIC1a inhibitors. Among them, compound 5e showed the most activity to inhibit [Ca2+]i. elevation in acid-induced articular chondrocytes. Together with the important role of ASIC1a in the pathogenesis of tissue acidification diseases including rheumatoid arthritis, these results might provide a meaningful hint or inspiration in developing drugs targeting at tissue acidification diseases.
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Affiliation(s)
- Hua Zhou
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei 230032, PR China
| | - Zhi Sen Wang
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei 230032, PR China
| | - Xin Hua Liu
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei 230032, PR China.
| | - Fei Hu Chen
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei 230032, PR China.
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41
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Shobair M, Popov KI, Dang YL, He H, Stutts MJ, Dokholyan NV. Mapping allosteric linkage to channel gating by extracellular domains in the human epithelial sodium channel. J Biol Chem 2018; 293:3675-3684. [PMID: 29358325 DOI: 10.1074/jbc.ra117.000604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 01/08/2018] [Indexed: 11/06/2022] Open
Abstract
The epithelial sodium channel (ENaC) mediates sodium absorption in lung, kidney, and colon epithelia. Channels in the ENaC/degenerin family possess an extracellular region that senses physicochemical changes in the extracellular milieu and allosterically regulates the channel opening. Proteolytic cleavage activates the ENaC opening, by the removal of specific segments in the finger domains of the α- and γ ENaC-subunits. Cleavage causes perturbations in the extracellular region that propagate to the channel gate. However, it is not known how the channel structure mediates the propagation of activation signals through the extracellular sensing domains. Here, to identify the structure-function determinants that mediate allosteric ENaC activation, we performed MD simulations, thiol modification of residues substituted by cysteine, and voltage-clamp electrophysiology recordings. Our simulations of an ENaC heterotetramer, α1βα2γ, in the proteolytically cleaved and uncleaved states revealed structural pathways in the α-subunit that are responsible for ENaC proteolytic activation. To validate these findings, we performed site-directed mutagenesis to introduce cysteine substitutions in the extracellular domains of the α-, β-, and γ ENaC-subunits. Insertion of a cysteine at the α-subunit Glu557 site, predicted to stabilize a closed state of ENaC, inhibited ENaC basal activity and retarded the kinetics of proteolytic activation by 2-fold. Our results suggest that the lower palm domain of αENaC is essential for ENaC activation. In conclusion, our integrated computational and experimental approach suggests key structure-function determinants for ENaC proteolytic activation and points toward a mechanistic model for the allosteric communication in the extracellular domains of the ENaC/degenerin family channels.
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Affiliation(s)
- Mahmoud Shobair
- From the Program in Molecular and Cellular Biophysics.,Curriculum in Bioinformatics and Computational Biology.,Department of Biochemistry and Biophysics, and.,Cystic Fibrosis and Pulmonary Diseases Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | | | - Yan L Dang
- Cystic Fibrosis and Pulmonary Diseases Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Hong He
- Cystic Fibrosis and Pulmonary Diseases Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - M Jackson Stutts
- Cystic Fibrosis and Pulmonary Diseases Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Nikolay V Dokholyan
- From the Program in Molecular and Cellular Biophysics, .,Curriculum in Bioinformatics and Computational Biology.,Department of Biochemistry and Biophysics, and.,Cystic Fibrosis and Pulmonary Diseases Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
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42
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So EC, Wang Y, Yang LQ, So KH, Lo YC, Wu SN. Multiple regulatory actions of 2-guanidine-4-methylquinazoline (GMQ), an agonist of acid-sensing ion channel type 3, on ionic currents in pituitary GH 3 cells and in olfactory sensory (Rolf B1.T) neurons. Biochem Pharmacol 2018; 151:79-88. [PMID: 29477572 DOI: 10.1016/j.bcp.2018.02.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 02/20/2018] [Indexed: 11/26/2022]
Abstract
GMQ (2-guanidine-4-methylquinazoline or N-(4-methyl-2-quinazolinyl)-guanidine hydrochloride), an agonist of acid-sensing ion channel type 3, has been increasingly used for in vivo studies of alternations in nociceptic behavior. In this study, we tried to investigate whether GMQ has any possible effect on other types of ion channels. Addition of GMQ to pituitary GH3 cells raised the amplitude of Ca2+-activated K+ currents (IK(Ca)), which was reversed by verruculogen or PF1022A, but not by TRAM-39. Under inside-out current recordings, addition of GMQ into bath enhanced the probability of large-conductance Ca2+-activated K+ (BKCa) channels with an EC50 value of 0.95 µM. The activation curve of BKCa channels during exposure to GMQ shifted to a lower depolarized potential, with no change in the gating charge of the curve; however, there was a reduction of free energy for channel activation in its presence. As cells were exposed to GMQ, the amplitude of ion currents were suppressed, including delayed rectifying K+ current, voltage-gated Na+ and L-type Ca2+ currents. In Rolf B1.T olfactory sensory neuron, addition of GMQ was able to induce inward current and to suppress peak INa. Taken together, findings from these results indicated that in addition to the activation of ASIC3 channels, this compound might directly produce additional actions on various types of ion channels. Caution should be taken in the interpretation of in vivo experimental results when GMQ or other structurally similar compounds are used as targets to characterize the potential functions of ASIC3 channels.
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Affiliation(s)
- Edmund Cheung So
- Department of Anesthesia, An Nan Hospital, China Medical University, 70965 Tainan City, Taiwan; Department of Anesthesia, China Medical University, 40447 Taichung City, Taiwan
| | - Yingwei Wang
- Department of Anesthesia, Huashan Hospital, Fudan University, Shanghai City, China.
| | - Li Qun Yang
- Department of Anesthesia, Renji Hospital, Jiaotong University School of Medicine, Shanghai City, China
| | - Kenny Hsu So
- Department of Medicine, Shanghai Medical College, Fudan University, Shanghai City, China
| | - Yi-Ching Lo
- Department of Pharmacology, Kaohsiung Medical University, Kaohsiung City, Taiwan.
| | - Sheng-Nan Wu
- Department of Physiology, National Cheng Kung University Medical College, 70101 Tainan City, Taiwan.
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Sakka M, Leschiera R, Le Gall-Ianotto C, Gouin O, L'herondelle K, Buscaglia P, Mignen O, Philbé JL, Saguet T, Carré JL, Misery L, Lebonvallet N. A new tool to test active ingredient using lactic acid in vitro, a help to understand cellular mechanism involved in stinging test: An example using a bacterial polysaccharide (Fucogel ® ). Exp Dermatol 2018; 27:238-244. [PMID: 29280518 DOI: 10.1111/exd.13489] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2017] [Indexed: 12/15/2022]
Abstract
The stinging test is an in vivo protocol that evaluates sensitive skin using lactic acid (LA). A soothing sensation of cosmetics or ingredients can be also appreciated through a decrease in stinging score. To predict the soothing sensation of a product before in vivo testing, we developed a model based on an LA test and substance P (SP) release using a co-culture of human keratinocytes and NGF-differentiated PC12 cells. A bacterial fucose-rich polysaccharide present in Fucogel® was evaluated as the soothing molecule in the in vivo stinging test and our in vitro model. Excluding toxic concentrations, the release of SP was significant from 0.2% of lactic acid for the PC12 cells and from 0.1% of lactic acid for the keratinocytes. When the pH was adjusted to approximately 7.4, LA did not provoke SP release. At these concentrations of LA, 0.1% of polysaccharide showed a significant decrease in SP release from the two cellular types and in co-cultures without modifying the pH of the medium. In vivo, a stinging test using the polysaccharide showed a 30% decrease in prickling intensity vs the placebo in 19 women between the ages of 21 and 69. Our in vitro model is ethically interesting and is adapted for cosmetic ingredients screening because it does not use animal experimentation and limits human volunteers. Moreover, Fucogel® reduced prickling sensation as revealed by the in vivo stinging test and inhibits the neurogenic inflammation as showed by our new in vitro stinging test based on SP release.
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Affiliation(s)
- Mehdi Sakka
- Laboratory Interactions Neurons-Keratinocytes, University of Western Brittany, Brest, France
| | - Raphael Leschiera
- Laboratory Interactions Neurons-Keratinocytes, University of Western Brittany, Brest, France
| | | | - Olivier Gouin
- Laboratory Interactions Neurons-Keratinocytes, University of Western Brittany, Brest, France
| | - Killian L'herondelle
- Laboratory Interactions Neurons-Keratinocytes, University of Western Brittany, Brest, France
| | - Paul Buscaglia
- INSERM U1227 "Lymphocyte B et Auto-Immunité", Brest, France
| | - Olivier Mignen
- INSERM U1227 "Lymphocyte B et Auto-Immunité", Brest, France
| | | | | | - Jean-Luc Carré
- Laboratory Interactions Neurons-Keratinocytes, University of Western Brittany, Brest, France
| | - Laurent Misery
- Laboratory Interactions Neurons-Keratinocytes, University of Western Brittany, Brest, France
| | - Nicolas Lebonvallet
- Laboratory Interactions Neurons-Keratinocytes, University of Western Brittany, Brest, France
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Vann KT, Xiong ZG. Acid-sensing ion channel 1 contributes to normal olfactory function. Behav Brain Res 2018; 337:246-251. [PMID: 28912013 PMCID: PMC5645255 DOI: 10.1016/j.bbr.2017.09.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 09/01/2017] [Accepted: 09/06/2017] [Indexed: 11/21/2022]
Abstract
Acid-sensing ion channels (ASICs) are cation channels activated by protons. ASIC1a, a primary ASIC subunit in the brain, was recently characterized in the olfactory bulb. The present study tested the hypothesis that ASIC1a is essential for normal olfactory function. Olfactory behavior of wild-type (WT) and ASIC1-/- mice was evaluated by using three standard olfactory tests: (1) the buried food test, (2) the olfactory habituation test, and (3) the olfactory preference test. In buried food test, ASIC1-/- mice had significantly longer latency to uncover buried food than WT mice. In olfactory habituation test, ASIC1-/- mice had increased sniffing time with acidic odorants. In olfactory preference test, ASIC1-/- mice did not exhibit normal avoidance behavior for 2, 5- dihydro-2, 4, 5-trimethylthiazoline (TMT). Consistent with ASIC1 knockout, ASIC1 inhibition by nasal administration of PcTX1 increased the latency for WT mice to uncover the buried food. Together, these findings suggest a key role for ASIC1a in normal olfactory function.
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Affiliation(s)
- Kiara T Vann
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, Georgia.
| | - Zhi-Gang Xiong
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, Georgia.
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45
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Collina S, Rui M, Stotani S, Bignardi E, Rossi D, Curti D, Giordanetto F, Malacrida A, Scuteri A, Cavaletti G. Are sigma receptor modulators a weapon against multiple sclerosis disease? Future Med Chem 2017; 9:2029-2051. [PMID: 29076758 DOI: 10.4155/fmc-2017-0122] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
Effective therapies for multiple sclerosis (MS) are still missing. This neurological disease affects more than 2.5 million people worldwide. To date, biological immunomodulatory drugs are effective and safe during short-term treatment, but they are suitable only for parenteral administration and they are expensive. Accordingly, academic and industrial environments are still focusing their efforts toward the development of new MS drugs. Considering that neurodegeneration is a contributory factor in the onset of MS, herein we will focus on the crucial role played by sigma 1 receptors (S1Rs) in MS. A pilot study was performed, evaluating the effect of the S1R agonist (R)-RC33 on rat dorsal root ganglia experimental model. The encouraging results support the potential of S1R agonists for MS treatment.
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Affiliation(s)
- Simona Collina
- Department of Drug Sciences, Medicinal Chemistry & Pharmaceutical Technology Section, Centre for Health Technologies (CHT), University of Pavia, Viale Taramelli 12, Pavia 27100, Italy
| | - Marta Rui
- Department of Drug Sciences, Medicinal Chemistry & Pharmaceutical Technology Section, Centre for Health Technologies (CHT), University of Pavia, Viale Taramelli 12, Pavia 27100, Italy
| | - Silvia Stotani
- Medicinal Chemistry, Taros Chemicals GmbH & Co. KG, Emil-Figge-Str. 76a, Dortmund 44227, Germany
| | - Emanuele Bignardi
- Department of Drug Sciences, Medicinal Chemistry & Pharmaceutical Technology Section, Centre for Health Technologies (CHT), University of Pavia, Viale Taramelli 12, Pavia 27100, Italy
| | - Daniela Rossi
- Department of Drug Sciences, Medicinal Chemistry & Pharmaceutical Technology Section, Centre for Health Technologies (CHT), University of Pavia, Viale Taramelli 12, Pavia 27100, Italy
| | - Daniela Curti
- Department of Biology & Biotechnology 'L. Spallanzani', Laboratory of Cellular & Molecular Neuropharmacology, University of Pavia, Via Ferrata 9, Pavia 27100, Italy
| | | | - Alessio Malacrida
- Experimental Neurology Unit, Department of Medicine & Surgery & Milan Center for Neuroscience, University of Milan Bicocca, Via Cadore 48, Monza 20900, Italy
| | - Arianna Scuteri
- Experimental Neurology Unit, Department of Medicine & Surgery & Milan Center for Neuroscience, University of Milan Bicocca, Via Cadore 48, Monza 20900, Italy
| | - Guido Cavaletti
- Experimental Neurology Unit, Department of Medicine & Surgery & Milan Center for Neuroscience, University of Milan Bicocca, Via Cadore 48, Monza 20900, Italy
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46
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Solé-Magdalena A, Martínez-Alonso M, Coronado CA, Junquera LM, Cobo J, Vega JA. Molecular basis of dental sensitivity: The odontoblasts are multisensory cells and express multifunctional ion channels. Ann Anat 2017; 215:20-29. [PMID: 28954208 DOI: 10.1016/j.aanat.2017.09.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 08/22/2017] [Accepted: 09/10/2017] [Indexed: 12/26/2022]
Abstract
Odontoblasts are the dental pulp cells responsible for the formation of dentin. In addition, accumulating data strongly suggest that they can also function as sensory cells that mediate the early steps of mechanical, thermic, and chemical dental sensitivity. This assumption is based on the expression of different families of ion channels involved in various modalities of sensitivity and the release of putative neurotransmitters in response to odontoblast stimulation which are able to act on pulp sensory nerve fibers. This review updates the current knowledge on the expression of transient-potential receptor ion channels and acid-sensing ion channels in odontoblasts, nerve fibers innervating them and trigeminal sensory neurons, as well as in pulp cells. Moreover, the innervation of the odontoblasts and the interrelationship been odontoblasts and nerve fibers mediated by neurotransmitters was also revisited. These data might provide the basis for novel therapeutic approaches for the treatment of dentin sensibility and/or dental pain.
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Affiliation(s)
- A Solé-Magdalena
- Departamento de Morfología y Biología Celular Universidad de Oviedo, Spain
| | - M Martínez-Alonso
- Departamento de Morfología y Biología Celular Universidad de Oviedo, Spain
| | - C A Coronado
- Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Temuco, Chile
| | - L M Junquera
- Departamento de Especialidades Médico-Quirúrgicas, Universidad de Oviedo, Spain; Servicio de Cirugía Maxilofacial, Hospital Universitario Central de Asturias, Oviedo, Spain
| | - J Cobo
- Departamento de Especialidades Médico-Quirúrgicas, Universidad de Oviedo, Spain; Instituto Asturiano de Odontología, Oviedo, Spain
| | - J A Vega
- Departamento de Morfología y Biología Celular Universidad de Oviedo, Spain; Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Temuco, Chile.
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47
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Du J, Price MP, Taugher RJ, Grigsby D, Ash JJ, Stark AC, Hossain Saad MZ, Singh K, Mandal J, Wemmie JA, Welsh MJ. Transient acidosis while retrieving a fear-related memory enhances its lability. eLife 2017; 6:e22564. [PMID: 28650315 PMCID: PMC5484615 DOI: 10.7554/elife.22564] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Accepted: 06/13/2017] [Indexed: 02/02/2023] Open
Abstract
Attenuating the strength of fearful memories could benefit people disabled by memories of past trauma. Pavlovian conditioning experiments indicate that a retrieval cue can return a conditioned aversive memory to a labile state. However, means to enhance retrieval and render a memory more labile are unknown. We hypothesized that augmenting synaptic signaling during retrieval would increase memory lability. To enhance synaptic transmission, mice inhaled CO2 to induce an acidosis and activate acid sensing ion channels. Transient acidification increased the retrieval-induced lability of an aversive memory. The labile memory could then be weakened by an extinction protocol or strengthened by reconditioning. Coupling CO2 inhalation to retrieval increased activation of amygdala neurons bearing the memory trace and increased the synaptic exchange from Ca2+-impermeable to Ca2+-permeable AMPA receptors. The results suggest that transient acidosis during retrieval renders the memory of an aversive event more labile and suggest a strategy to modify debilitating memories.
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Affiliation(s)
- Jianyang Du
- Departments of Internal Medicine, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, United States
- Department of Biological Sciences, University of Toledo, Toledo, United States
| | - Margaret P Price
- Departments of Internal Medicine, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Rebecca J Taugher
- Department of Psychiatry, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Daniel Grigsby
- Departments of Internal Medicine, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Jamison J Ash
- Departments of Internal Medicine, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Austin C Stark
- Departments of Internal Medicine, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, United States
| | | | - Kritika Singh
- Department of Biological Sciences, University of Toledo, Toledo, United States
| | - Juthika Mandal
- Department of Biological Sciences, University of Toledo, Toledo, United States
| | - John A Wemmie
- Department of Psychiatry, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, United States
- Department of Molecular Physiology and Biophysics, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, United States
- Department of Neurosurgery, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Michael J Welsh
- Departments of Internal Medicine, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, United States
- Department of Molecular Physiology and Biophysics, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, United States
- Department of Neurosurgery, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, United States
- Howard Hughes Medical Institute, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, United States
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Liu J, Tao H, Wang H, Dong F, Zhang R, Li J, Ge P, Song P, Zhang H, Xu P, Liu X, Shen C. Biological Behavior of Human Nucleus Pulposus Mesenchymal Stem Cells in Response to Changes in the Acidic Environment During Intervertebral Disc Degeneration. Stem Cells Dev 2017; 26:901-911. [PMID: 28298159 DOI: 10.1089/scd.2016.0314] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
An acidic environment is vital for the maintenance of cellular activities but can be affected tremendously during intervertebral disc degeneration (IVDD). The effect of changes in the acidity of the environment on human nucleus pulposus mesenchymal stem cells (NP-MSCs) is, however, unknown. Thus, this study aimed to observe the biological effects of acidic conditions mimicking a degenerated intervertebral disc on NP-MSCs in vitro. NP-MSCs were isolated from patients with lumbar disc herniation and were further identified by their immunophenotypes and multilineage differentiation. Then, cells were cultured at acidic pH levels (pH 6.2, pH 6.5, pH 6.8, pH 7.1, and pH 7.4) with/without amiloride, an acid-sensing ion channel (ASIC) blocker. The proliferation and apoptosis of NP-MSCs and the expression of stem cell-related genes (Oct4, Nanog, Jagged, Notch1), ASICs, and functional genes (Aggrecan, SOX-9, Collagen-I, and Collagen-II) in NP-MSCs were evaluated. Our work showed that cells obtained from human degenerated NP met the criteria of International Society for Cellular Therapy. Therefore, cells obtained from a degenerated nucleus pulposus were definitively identified as NP-MSCs. Our results also indicated that acidic conditions could significantly inhibit cell proliferation and increase cell apoptosis. Gene expression results demonstrated that acidic conditions could decrease the expression of stem cell-related genes and inhibit extracellular matrix synthesis, whereas it could increase the expression of ASICs. Our study further verified that the above-mentioned biological activities of NP-MSCs could be significantly improved by amiloride. Therefore, the results of the study indicated that the biological behavior of NP-MSCs could be inhibited by acidic conditions during IVDD, and amiloride may meliorate IVDD by improving the activities of NP-MSCs.
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Affiliation(s)
- Jianjun Liu
- 1 Department of Spine Surgery, The First Affiliated Hospital of Anhui Medical University , Hefei, People's Republic of China
| | - Hui Tao
- 1 Department of Spine Surgery, The First Affiliated Hospital of Anhui Medical University , Hefei, People's Republic of China
| | - Hanbang Wang
- 1 Department of Spine Surgery, The First Affiliated Hospital of Anhui Medical University , Hefei, People's Republic of China
| | - Fulong Dong
- 1 Department of Spine Surgery, The First Affiliated Hospital of Anhui Medical University , Hefei, People's Republic of China
| | - Renjie Zhang
- 1 Department of Spine Surgery, The First Affiliated Hospital of Anhui Medical University , Hefei, People's Republic of China
| | - Jie Li
- 2 Department of Clinical Laboratory, The First Affiliated Hospital of Anhui Medical University , Hefei, People's Republic of China
| | - Peng Ge
- 1 Department of Spine Surgery, The First Affiliated Hospital of Anhui Medical University , Hefei, People's Republic of China
| | - Peiwen Song
- 1 Department of Spine Surgery, The First Affiliated Hospital of Anhui Medical University , Hefei, People's Republic of China
| | - Huaqing Zhang
- 1 Department of Spine Surgery, The First Affiliated Hospital of Anhui Medical University , Hefei, People's Republic of China
| | - Peng Xu
- 1 Department of Spine Surgery, The First Affiliated Hospital of Anhui Medical University , Hefei, People's Republic of China
| | - Xiaoying Liu
- 3 Biology Department, School of Life Science, Anhui Medical University , Hefei, People's Republic of China
| | - Cailiang Shen
- 1 Department of Spine Surgery, The First Affiliated Hospital of Anhui Medical University , Hefei, People's Republic of China
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49
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Baldwin DS, Hou R, Gordon R, Huneke NTM, Garner M. Pharmacotherapy in Generalized Anxiety Disorder: Novel Experimental Medicine Models and Emerging Drug Targets. CNS Drugs 2017; 31:307-317. [PMID: 28303465 DOI: 10.1007/s40263-017-0423-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Many pharmacological and psychological approaches have been found efficacious in patients with generalized anxiety disorder (GAD), but many treatment-seeking patients will not respond and others will relapse despite continuing with interventions that initially had beneficial effects. Other patients will respond but then stop treatment early because of untoward effects such as sexual dysfunction, drowsiness, and weight gain. There is much scope for the development of novel approaches that could have greater overall effectiveness or acceptability than currently available interventions or that have particular effectiveness in specific clinical subgroups. 'Experimental medicine' studies in healthy volunteers model disease states and represent a proof-of-concept approach for the development of novel therapeutic interventions: they determine whether to proceed to pivotal efficacy studies and so can reduce delays in translating innovations into clinical practice. Investigations in healthy volunteers challenged with the inhalation of air 'enriched' with 7.5% carbon dioxide (CO2) indicate this technique provides a validated and robust experimental medicine model, mirroring the subjective, autonomic, and cognitive features of GAD. The anxiety response during CO2 challenge probably involves both central noradrenergic neurotransmission and effects on acid-base sensitive receptors and so may stimulate development of novel agents targeted at central chemosensors. Increasing awareness of the potential role of altered cytokine balance in anxiety and the interplay of cytokines with monoaminergic mechanisms may also encourage the investigation of novel agents with modulating effects on immunological profiles. Although seemingly disparate, these two approaches to treatment development may pivot on a shared mechanism in exerting anxiolytic-like effects through pharmacological effects on acid-sensing ion channels.
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Affiliation(s)
- David S Baldwin
- Clinical and Experimental Sciences Academic Unit, Faculty of Medicine, University of Southampton, Southampton, UK. .,University Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa. .,University Department of Psychiatry, Academic Centre, College Keep, 4-12 Terminus Terrace, Southampton, SO14 3DT, UK.
| | - Ruihua Hou
- Clinical and Experimental Sciences Academic Unit, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Robert Gordon
- Clinical and Experimental Sciences Academic Unit, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Nathan T M Huneke
- Clinical and Experimental Sciences Academic Unit, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Matthew Garner
- Clinical and Experimental Sciences Academic Unit, Faculty of Medicine, University of Southampton, Southampton, UK.,Academic Unit of Psychology, Faculty of Social, Human and Mathematical Sciences, University of Southampton, Southampton, UK
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Mukhopadhyay M, Singh A, Sachchidanand S, Bera AK. Quercetin inhibits acid-sensing ion channels through a putative binding site in the central vestibular region. Neuroscience 2017; 348:264-272. [PMID: 28237818 DOI: 10.1016/j.neuroscience.2017.02.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 02/02/2017] [Accepted: 02/13/2017] [Indexed: 12/20/2022]
Abstract
Acid-sensing ion channels (ASICs) are associated with many pathophysiological processes, such as neuronal death during ischemic stroke, epileptic seizure and nociception. However, there is a dearth of ASIC-specific therapeutic blockers. Here we report that quercetin, a plant flavonoid, which is known for its neuroprotective effect, reversibly inhibits homomeric rat ASIC1a, ASIC2a and ASIC3 with an IC50 of about 2µM. Also, quercetin prevents low pH-induced intracellular calcium rise and cell death in HEK-293 cells, which have endogenous expression of ASIC1a and 2a. The inhibitory effect of quercetin on ASICs is not due to membrane perturbation, as it did not have any effect on other channels, like NMDA receptor, GABAA receptor and P2X4 receptor. Unlike quercetin, another flavonoid resveratrol had no effect on ASIC1a. Computational analysis revealed that quercetin binds to the channel in a cavity at the central vestibule, lined by several charged residues like Q276, R369, E373 and E416 in ASIC1a. Mutation of Arg369 to Ala or Glu416 to Gln abolished the inhibitory effect of quercetin on rat ASIC1a completely, while Glu373 to Gln showed reduced sensitivity. Our results raise the possibility of using quercetin for targeting ASICs in vivo.
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Affiliation(s)
- Mohona Mukhopadhyay
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences Building, Indian Institute of Technology Madras, Chennai 600036, India
| | - Anurag Singh
- National Institute of Pharmaceutical Education and Research (NIPER) Hajipur, Bihar, India
| | - S Sachchidanand
- National Institute of Pharmaceutical Education and Research (NIPER) Hajipur, Bihar, India
| | - Amal Kanti Bera
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences Building, Indian Institute of Technology Madras, Chennai 600036, India.
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