Ion Channels in Mesangial Cells: Function, Malfunction, or Fiction

Physiology ◽  
2005 ◽  
Vol 20 (2) ◽  
pp. 102-111 ◽  
Author(s):  
Rong Ma ◽  
Jennifer L. Pluznick ◽  
Steven C. Sansom
Keyword(s):  
Ion Channels ◽  
Transient Receptor Potential ◽  
Mesangial Cells ◽  
Gene Knockout ◽  
Receptor Potential ◽  
Mouse Cell ◽  
Glomerular Mesangial Cells ◽  
Α Subunit ◽  
Transient Receptor ◽  
And Function

Ion channels in glomerular mesangial cells from humans, rats, and mice have been studied by electrophysiological, molecular, and gene-knockout methods. Two channels, a large, Ca2+-activated K+ channel (BK) and a store-operated Ca2+ channel (SOCC), can be defined with respect to molecular structure and function. Human BK, comprised of a pore-forming α-subunit and an accessory β1-subunit, operate as Ca2+-sensing feedback modulators of contractile tone. SOCC have also been characterized in a mouse cell line; they are comprised of molecules belonging to the transient receptor potential subfamily.

scholarly journals Impact of Diverse Ion Channels on Regulatory T Cell Functions

2021 ◽  
Vol 55 (S3) ◽  
pp. 145-156
Keyword(s):  
Ion Channels ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Future Research ◽  
Ion Regulation ◽  
Cell Functions ◽  
Treg Number ◽  
Promising Therapeutic Approach ◽  
Transient Receptor ◽  
And Function

The population of regulatory T cells (Tregs) is critical for immunological self-tolerance and homeostasis. Proper ion regulation contributes to Treg lineage identity, regulation, and effector function. Identified ion channels include Ca2+ release-activated Ca2+, transient receptor potential, P2X, volume-regulated anion and K+ channels Kv1.3 and KCa3.1. Ion channel modulation represents a promising therapeutic approach for the treatment of autoimmune diseases such as rheumatoid arthritis and multiple sclerosis. This review summarizes studies with gene-targeted mice and pharmacological modulators affecting Treg number and function. Furthermore, participation of ion channels is illustrated and the power of future research possibilities is discussed.

scholarly journals Noncanonical Ion Channel Behaviour in Pain

2019 ◽  
Vol 20 (18) ◽  
pp. 4572 ◽  
Author(s):  
Cosmin I. Ciotu ◽  
Christoforos Tsantoulas ◽  
Jannis Meents ◽  
Angelika Lampert ◽  
Stephen B. McMahon ◽  
...  
Keyword(s):  
Ion Channels ◽  
Transient Receptor Potential ◽  
Cluster Formation ◽  
Receptor Potential ◽  
Chemical Exposure ◽  
Sodium Potassium ◽  
Fundamental Properties ◽  
Conductivity Structure ◽  
Transient Receptor ◽  
And Function

Ion channels contribute fundamental properties to cell membranes. Although highly diverse in conductivity, structure, location, and function, many of them can be regulated by common mechanisms, such as voltage or (de-)phosphorylation. Primarily considering ion channels involved in the nociceptive system, this review covers more novel and less known features. Accordingly, we outline noncanonical operation of voltage-gated sodium, potassium, transient receptor potential (TRP), and hyperpolarization-activated cyclic nucleotide (HCN)-gated channels. Noncanonical features discussed include properties as a memory for prior voltage and chemical exposure, alternative ion conduction pathways, cluster formation, and silent subunits. Complementary to this main focus, the intention is also to transfer knowledge between fields, which become inevitably more separate due to their size.

scholarly journals Nanomolar ouabain increases NCX1 expression and enhances Ca2+ signaling in human arterial myocytes: a mechanism that links salt to increased vascular resistance?

2012 ◽  
Vol 303 (7) ◽  
pp. H784-H794 ◽  
Author(s):  
Cristina I. Linde ◽  
Laura K. Antos ◽  
Vera A. Golovina ◽  
Mordecai P. Blaustein
Keyword(s):  
Vascular Resistance ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Whole Body ◽  
Membrane Microdomains ◽  
Α Subunit ◽  
Plasmic Reticulum ◽  
Endogenous Ouabain ◽  
Transient Receptor ◽  
And Function

The mechanisms by which NaCl raises blood pressure (BP) in hypertension are unresolved, but much evidence indicates that endogenous ouabain is involved. In rodents, arterial smooth muscle cell (ASMC) Na+ pumps with an α2-catalytic subunit (ouabain EC50 ≤1.0 nM) are crucial for some hypertension models, even though ≈80% of ASMC Na+ pumps have an α1-subunit (ouabain EC50 ≈ 5 μM). Human α1-Na+ pumps, however, have high ouabain affinity (EC50 ≈ 10–20 nM). We used immunoblotting, immunocytochemistry, and Ca2+ imaging (fura-2) to examine the expression, distribution, and function of Na+ pump α-subunit isoforms in human arteries and primary cultured human ASMCs (hASMCs). hASMCs express α1- and α2-Na+ pumps. Further, α2-, but not α1-, pumps are confined to plasma membrane microdomains adjacent to sarcoplasmic reticulum (SR), where they colocalize with Na/Ca exchanger-1 (NCX1) and C-type transient receptor potential-6 (receptor-operated channels, ROCs). Prolonged inhibition (72 h) with 100 nM ouabain (blocks nearly all α1- and α2-pumps) was toxic to most cultured hASMCs. Treatment with 10 nM ouabain (72 h), however, increased NCX1 and sarco(endo)plasmic reticulum Ca2+-ATPase expression and augmented ATP (10 μM)-induced SR Ca2+ release in 0 Ca2+, ouabain-free media, and Ca2+ influx after external Ca2+ restoration. The latter was likely mediated primarily by ROCs and store-operated Ca2+ channels. These hASMC protein expression and Ca2+ signaling changes are comparable with previous observations on myocytes isolated from arteries of many rat hypertension models. We conclude that the same structurally and functionally coupled mechanisms (α2-Na+ pumps, NCX1, ROCs, and the SR) regulate Ca2+ homeostasis and signaling in hASMCs and rodent ASMCs. These ouabain/endogenous ouabain-modulated mechanisms underlie the whole body autoregulation associated with increased vascular resistance and elevation of BP in human, salt-sensitive hypertension.

scholarly journals Transient Receptor Potential Melastatin 2 Enhances Vascular Reactivity During Development of Atherosclerosis in Mice

2021 ◽  
Vol 34 (1) ◽  
pp. 121-122
Author(s):  
Yi-quan Dai ◽  
Xiao-xiao Yan ◽  
Yi-chen Lin ◽  
Hong-yu Chen ◽  
Xiao-ru Liu
Keyword(s):  
Knockout Mice ◽  
Vascular Reactivity ◽  
Transient Receptor Potential ◽  
Gene Knockout ◽  
Receptor Potential ◽  
Blood Lipid ◽  
Normal Diet ◽  
Protein Levels ◽  
Transient Receptor Potential Melastatin ◽  
Transient Receptor

Abstract Background To investigate the function of transient receptor potential melastatin 2 (TRPM2) in vascular reactivity induced by 5-hydroxytryptamine (5-HT) in the aorta during development of atherosclerosis in mice. Methods Forty mice were randomly divided into 4 groups: C57BL/6J on normal diet (C57 + ND), C57BL/6J on high-fat diet (C57 + HFD), apolipoprotein E gene knockout mice (ApoE−/−) on ND (ApoE−/− + ND), and ApoE−/− on HFD (ApoE−/− + HFD). They were fed with a ND or HFD for 16 weeks. Aortic TRPM2 expression and isometric contractions were analyzed. Results In the ApoE−/− + HFD group, body weight, blood glucose, and blood lipid concentrations were increased, and aortic plaques were developed. Compared with the other 3 groups, aortic TRPM2 mRNA and protein levels were significantly increased in the ApoE−/− + HFD group (P < 0.01). Aortic reactivity to 5-HT was enhanced in ApoE−/− + HFD mice with lower EC50 values. The enhanced reactivity to 5-HT was significantly inhibited by TRPM2 inhibitors, N-p-amylcinnamoyl anthranilic acid (1 µmol/l) and 2-aminoethyl diphenylborinate (10 µmol/l). Conclusions Aortic TRPM2 expression is upregulated in ApoE knockout mice fed with a HFD. Upregulation of TRPM2 enhances 5-HT vascular reactivity during development of atherosclerosis.

TRPC1, TRPC3, and TRPC4 in Rat Orofacial Structures

2017 ◽  
Vol 204 (5-6) ◽  
pp. 293-303 ◽  
Author(s):  
Masatoshi Fujita ◽  
Tadasu Sato ◽  
Takehiro Yajima ◽  
Eiji Masaki ◽  
Hiroyuki Ichikawa
Keyword(s):  
Transient Receptor Potential ◽  
Sympathetic Neurons ◽  
Receptor Potential ◽  
Monovalent Cation ◽  
Calcitonin Gene ◽  
Cervical Ganglion ◽  
Parasympathetic Neurons ◽  
Transient Receptor ◽  
And Function ◽  
And Control

TRPC (transient receptor potential cation channel subfamily C) members are nonselective monovalent cation channels and control Ca2+ inflow. In this study, immunohistochemistry for TRPC1, TRPC3, and TRPC4 was performed on rat oral and craniofacial structures to elucidate their distribution and function in the peripheries. In the trigeminal ganglion (TG), 56.1, 84.1, and 68.3% of sensory neurons were immunoreactive (IR) for TRPC1, TRPC3, and TRPC4, respectively. A double immunofluorescence method revealed that small to medium-sized TG neurons co-expressed TRPCs and calcitonin gene-related peptide. In the superior cervical ganglion, all sympathetic neurons showed TRPC1 and TRPC3 immunoreactivity. Parasympathetic neurons in the submandibular ganglion, tongue, and parotid gland were TRPC1, TRPC3, and TRPC4 IR. Gustatory and olfactory cells were also IR for TRPC1, TRPC3, and/or TRPC4. In the musculature, motor endplates expressed TRPC1 and TRPC4 immunoreactivity. It is likely that TRPCs are associated with sensory, autonomic, and motor functions in oral and craniofacial structures.

scholarly journals The transient receptor potential, TRP4, cation channel is a novel member of the family of calmodulin binding proteins

2001 ◽  
Vol 355 (3) ◽  
pp. 663-670 ◽  
Author(s):  
Claudia TROST ◽  
Christiane BERGS ◽  
Nina HIMMERKUS ◽  
Veit FLOCKERZI
Keyword(s):  
Amino Acid ◽  
Ion Channels ◽  
Transient Receptor Potential ◽  
Direct Interaction ◽  
Receptor Potential ◽  
Amino Acid Residues ◽  
Glutathione S Transferase ◽  
Calmodulin Binding ◽  
Transient Receptor

The mammalian gene products, transient receptor potential (trp)1 to trp7, are related to the Drosophila TRP and TRP-like ion channels, and are candidate proteins underlying agonist-activated Ca2+-permeable ion channels. Recently, the TRP4 protein has been shown to be part of native store-operated Ca2+-permeable channels. These channels, most likely, are composed of other proteins in addition to TRP4. In the present paper we report the direct interaction of TRP4 and calmodulin (CaM) by: (1) retention of in vitro translated TRP4 and of TRP4 protein solubilized from bovine adrenal cortex by CaM–Sepharose in the presence of Ca2+, and (2) TRP4–glutathione S-transferase pull-down experiments. Two domains of TRP4, amino acid residues 688–759 and 786–848, were identified as being able to interact with CaM. The binding of CaM to both domains occurred only in the presence of Ca2+ concentrations above 10µM, with half maximal binding occurring at 16.6µM (domain 1) and 27.9µM Ca2+ (domain 2). Synthetic peptides, encompassing the two putative CaM binding sites within these domains and covering amino acid residues 694–728 and 829–853, interacted directly with dansyl–CaM with apparent Kd values of 94–189nM. These results indicate that TRP4/Ca2+-CaM are parts of a signalling complex involved in agonist-induced Ca2+ entry.

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