Effect of Xylo-Oligosaccharides Supplementation by Drinking Water on the Bone Properties and Related Calcium Transporters in Growing Mice

Xylo-oligosaccharides (XOS), non-digestible oligosaccharides, have the potential to regulate intestinal microorganisms, and thus, improve host health, but little evidence exists for the prebiotic effects on bone health. This study evaluates the dose-response effect of XOS supplementation on bone properties, the morphology of the intestine, cecum pH, and cecum wall weight, as well as the related calcium transporters. Ninety-six 28-day-old male mice were randomized into one of four groups, fed the same commercial diet, and given different types of deionized water containing 0, 1, 2, or 4% XOS by concentration for 30 days. Eight mice were randomly selected to accomplish particular tasks every 10 days. No significant differences in serum Ca and P levels and growth performance were observed among the four studied groups. XOS intervention significantly decreased cecum pH and increased cecum wall weight in a dose-dependent manner. At the late growth stage, compared with 0% XOS, the bone mineral density (BMD) and bone-breaking strength in 4% XOS were significantly higher. The bone crystallinity with 4% XOS, measured by Raman spectrum, was significantly enhanced compared to that with 0% XOS during later growth. The villus height and villus height to crypt depth (VH:CD) were enhanced with an increase of XOS concentration during the later stage of growth. The expression of transient receptor potential vanillin receptor 6 (TRPV6) and Na+/Ca2+ exchanger 1 (NCX1) in the duodenum were enhanced by XOS supplementation. XOS exerted a positive influence on bone properties by decreasing the cecum pH, increasing the cecum wall and villus structure, and upregulating the expression of related calcium transporters.

Download Full-text

Potentiation of TRPC5 by Protons

Journal of Biological Chemistry ◽

10.1074/jbc.m702577200 ◽

2007 ◽

Vol 282 (46) ◽

pp. 33868-33878 ◽

Cited By ~ 60

Author(s):

Marcus Semtner ◽

Michael Schaefer ◽

Olaf Pinkenburg ◽

Tim D. Plant

Keyword(s):

Phospholipase C ◽

Transient Receptor Potential ◽

Single Channel ◽

Receptor Potential ◽

High Sensitivity ◽

Transient Receptor Potential Channel ◽

Extracellular Ph ◽

Dependent Manner ◽

Open Probability ◽

Transient Receptor

Mammalian members of the classical transient receptor potential channel subfamily (TRPC) are Ca2+-permeable cation channels involved in receptor-mediated increases in intracellular Ca2+. TRPC4 and TRPC5 form a group within the TRPC subfamily and are activated in a phospholipase C-dependent manner by an unidentified messenger. Unlike most other Ca2+-permeable channels, TRPC4 and -5 are potentiated by micromolar concentrations of La3+ and Gd3+. This effect results from an action of the cations at two glutamate residues accessible from the extracellular solution. Here, we show that TRPC4 and -5 respond to changes in extracellular pH. Lowering the pH increased both G protein-activated and spontaneous TRPC5 currents. Both effects were already observed with small reductions in pH (from 7.4 to 7.0) and increased up to pH 6.5. TRPC4 was also potentiated by decreases in pH, whereas TRPC6 was only inhibited, with a pIC50 of 5.7. Mutation of the glutamate residues responsible for lanthanoid sensitivity of TRPC5 (E543Q and E595Q) modified the potentiation of TRPC5 by acid. Further evidence for a similarity in the actions of lanthanoids and H+ on TRPC5 is the reduction in single channel conductance and dramatic increase in channel open probability in the presence of either H+ or Gd3+ that leads to larger integral currents. In conclusion, the high sensitivity of TRPC5 to H+ indicates that, in addition to regulation by phospholipase C and other factors, the channel may act as a sensor of pH that links decreases in extracellular pH to Ca2+ entry and depolarization.

Download Full-text

The Na+/Ca2+ Exchanger Inhibitor, KB-R7943, Blocks a Nonselective Cation Channel Implicated in Chemosensory Transduction

Journal of Neurophysiology ◽

10.1152/jn.90903.2008 ◽

2009 ◽

Vol 101 (3) ◽

pp. 1151-1159 ◽

Cited By ~ 12

Author(s):

A. Pezier ◽

Y. V. Bobkov ◽

B. W. Ache

Keyword(s):

Transient Receptor Potential ◽

Single Channel ◽

Receptor Potential ◽

Trpc Channels ◽

Dependent Manner ◽

Open Probability ◽

Olfactory Transduction ◽

Voltage Dependent ◽

Chemosensory Transduction ◽

Transient Receptor

The mechanism(s) of olfactory transduction in invertebrates remains to be fully understood. In lobster olfactory receptor neurons (ORNs), a nonselective sodium-gated cation (SGC) channel, a presumptive transient receptor potential (TRP)C channel homolog, plays a crucial role in olfactory transduction, at least in part by amplifying the primary transduction current. To better determine the functional role of the channel, it is important to selectively block the channel independently of other elements of the transduction cascade, causing us to search for specific pharmacological blockers of the SGC channel. Given evidence that the Na+/Ca2+ exchange inhibitor, KB-R7943, blocks mammalian TRPC channels, we studied this probe as a potential blocker of the lobster SGC channel. KB-R7943 reversibly blocked the SGC current in both inside- and outside-out patch recordings in a dose- and voltage-dependent manner. KB-R7943 decreased the channel open probability without changing single channel amplitude. KB-R7943 also reversibly and in a dose-dependent manner inhibited both the odorant-evoked discharge of lobster ORNs and the odorant-evoked whole cell current. Our findings strongly imply that KB-R7943 potently blocks the lobster SGC channel and likely does so directly and not through its ability to block the Na+/Ca2+ exchanger.

Download Full-text

The nonselective cation channel TRPV4 inhibits angiotensin II receptors

Journal of Biological Chemistry ◽

10.1074/jbc.ra120.014325 ◽

2020 ◽

Vol 295 (29) ◽

pp. 9986-9997

Author(s):

Nicholas W. Zaccor ◽

Charlotte J. Sumner ◽

Solomon H. Snyder

Keyword(s):

Angiotensin Ii ◽

G Protein ◽

Transient Receptor Potential ◽

Trp Channels ◽

Receptor Potential ◽

Trp Channel ◽

Luciferase Assay ◽

Transient Receptor Potential Vanilloid ◽

Dependent Manner ◽

Transient Receptor

G-protein–coupled receptors (GPCRs) are a ubiquitously expressed family of receptor proteins that regulate many physiological functions and other proteins. They act through two dissociable signaling pathways: the exchange of GDP to GTP by linked G-proteins and the recruitment of β-arrestins. GPCRs modulate several members of the transient receptor potential (TRP) channel family of nonselective cation channels. How TRP channels reciprocally regulate GPCR signaling is less well-explored. Here, using an array of biochemical approaches, including immunoprecipitation and fluorescence, calcium imaging, phosphate radiolabeling, and a β-arrestin–dependent luciferase assay, we characterize a GPCR–TRP channel pair, angiotensin II receptor type 1 (AT1R), and transient receptor potential vanilloid 4 (TRPV4), in primary murine choroid plexus epithelial cells and immortalized cell lines. We found that AT1R and TRPV4 are binding partners and that activation of AT1R by angiotensin II (ANGII) elicits β-arrestin–dependent inhibition and internalization of TRPV4. Activating TRPV4 with endogenous and synthetic agonists inhibited angiotensin II–mediated G-protein–associated second messenger accumulation, AT1R receptor phosphorylation, and β-arrestin recruitment. We also noted that TRPV4 inhibits AT1R phosphorylation by activating the calcium-activated phosphatase calcineurin in a Ca2+/calmodulin–dependent manner, preventing β-arrestin recruitment and receptor internalization. These findings suggest that when TRP channels and GPCRs are co-expressed in the same tissues, many of these channels can inhibit GPCR desensitization.

Download Full-text

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

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00336.2014 ◽

2015 ◽

Vol 308 (6) ◽

pp. G489-G496 ◽

Cited By ~ 13

Author(s):

Xiaoyun Yu ◽

Youtian Hu ◽

Fei Ru ◽

Marian Kollarik ◽

Bradley J. Undem ◽

...

Keyword(s):

Transient Receptor Potential ◽

Calcium Influx ◽

Ex Vivo ◽

Receptor Potential ◽

Sensory Transduction ◽

Dependent Manner ◽

Preferential Expression ◽

C Fibers ◽

C Fiber ◽

Transient Receptor

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

Download Full-text

Structure of the human TRPM4 ion channel in a lipid nanodisc

Science ◽

10.1126/science.aar4510 ◽

2017 ◽

Vol 359 (6372) ◽

pp. 228-232 ◽

Cited By ~ 129

Author(s):

Henriette E. Autzen ◽

Alexander G. Myasnikov ◽

Melody G. Campbell ◽

Daniel Asarnow ◽

David Julius ◽

...

Keyword(s):

Conformational Changes ◽

Calcium Binding ◽

Transient Receptor Potential ◽

Trp Channels ◽

Receptor Potential ◽

Dependent Manner ◽

Calcium Binding Site ◽

Voltage Dependent ◽

Transient Receptor ◽

Lipid Nanodiscs

Transient receptor potential (TRP) melastatin 4 (TRPM4) is a widely expressed cation channel associated with a variety of cardiovascular disorders. TRPM4 is activated by increased intracellular calcium in a voltage-dependent manner but, unlike many other TRP channels, is permeable to monovalent cations only. Here we present two structures of full-length human TRPM4 embedded in lipid nanodiscs at ~3-angstrom resolution, as determined by single-particle cryo–electron microscopy. These structures, with and without calcium bound, reveal a general architecture for this major subfamily of TRP channels and a well-defined calcium-binding site within the intracellular side of the S1-S4 domain. The structures correspond to two distinct closed states. Calcium binding induces conformational changes that likely prime the channel for voltage-dependent opening.

Download Full-text

Structural insight into TRPV5 channel function and modulation

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1820323116 ◽

2019 ◽

Vol 116 (18) ◽

pp. 8869-8878 ◽

Cited By ~ 26

Author(s):

Shangyu Dang ◽

Mark K. van Goor ◽

Daniel Asarnow ◽

YongQiang Wang ◽

David Julius ◽

...

Keyword(s):

Transient Receptor Potential ◽

Receptor Potential ◽

Transient Receptor Potential Vanilloid ◽

Dependent Manner ◽

Calcium Dependent ◽

Resolution Electron ◽

Trpv Channels ◽

Transient Receptor ◽

Lipid Nanodiscs ◽

Insight Into

TRPV5 (transient receptor potential vanilloid 5) is a unique calcium-selective TRP channel essential for calcium homeostasis. Unlike other TRPV channels, TRPV5 and its close homolog, TRPV6, do not exhibit thermosensitivity or ligand-dependent activation but are constitutively open at physiological membrane potentials and modulated by calmodulin (CaM) in a calcium-dependent manner. Here we report high-resolution electron cryomicroscopy structures of truncated and full-length TRPV5 in lipid nanodiscs, as well as of a TRPV5 W583A mutant and TRPV5 in complex with CaM. These structures highlight the mechanism of calcium regulation and reveal a flexible stoichiometry of CaM binding to TRPV5.

Download Full-text

Abstract 326: TRPV2 Regulates Cardiomyocyte Function via Altering Ca 2+ Cycling

Circulation Research ◽

10.1161/res.111.suppl_1.a326 ◽

2012 ◽

Vol 111 (suppl_1) ◽

Author(s):

Xiaoqian Gao ◽

Sheryl Koch ◽

Min Jiang ◽

Nathan Robbins ◽

Wenfeng Cai ◽

...

Keyword(s):

Transient Receptor Potential ◽

Ventricular Myocytes ◽

Receptor Potential ◽

Ruthenium Red ◽

Transient Receptor Potential Vanilloid ◽

Dependent Manner ◽

Noxious Heat ◽

Cardiac Tissues ◽

Membrane Stretching ◽

Transient Receptor

TRPV2 is a member of transient receptor potential vanilloid (TRPV) family. As a Ca 2+ channel, it can detect various stimuli such as noxious heat (>52°C), membrane stretching, as well as a number of exogenous chemicals, including probenecid, 2-aminoethoxydiphenyl borate, and lysophospholipids. TRPV2 has been found in many tissue types, including neuron and kidney, but the function of TRPV2 in the heart is poorly understood. Here we show TRPV2 is involved in the Ca 2+ cycling process and then regulates the function of the cardiomyocyte. We identified the mRNA expression of TRPV2 in the cardiac tissues of mice using real-time PCR. By performing echocardiography we found that administration of probenecid, a selective TRPV2 agonist, increased cardiac ejection fraction in mice. This positive inotropic effect of probenecid was also shown in Langendorff perfused mice hearts as increased peak +dP/dt. In isolated ventricular myocytes, we found that probenecid significantly increased myocyte fractional shortening in a dose-dependent manner, which was fully blocked by ruthenium red, a non-selective TRPV2 blocker. We also performed fluorescent studies to examine myocyte Ca 2+ cycling. We found that probenecid significantly increased Ca 2+ transient and resting-state Ca 2+ sparks and this effect was eliminated by ruthenium red. When Ca 2+ storage in sarcoplasmic reticulum (SR) was depleted with caffeine, and SR Ca 2+ reuptake was blocked by thapsigargin at the same time, probenecid did not show any effects in either Ca 2+ transient or Ca 2+ sparks. Our patch clamp experiments indicate that probenecid treatment does not trigger any significant transmembrane Ca 2+ influx. These results point to the important role of TRPV2 in regulating SR Ca 2+ release. In conclusion, TRPV2 activation may contribute to increased SR Ca 2+ release, leading to the enhancement of myocyte contractility. Thus, TRPV2 plays a potentially important role in controlling the cellular function of heart.

Download Full-text

TLR4 activation of TRPC6-dependent calcium signaling mediates endotoxin-induced lung vascular permeability and inflammation

Journal of Experimental Medicine ◽

10.1084/jem.20111355 ◽

2012 ◽

Vol 209 (11) ◽

pp. 1953-1968 ◽

Cited By ~ 130

Author(s):

Mohammad Tauseef ◽

Nebojsa Knezevic ◽

Koteswara R. Chava ◽

Monica Smith ◽

Sukriti Sukriti ◽

...

Keyword(s):

Vascular Permeability ◽

Transient Receptor Potential ◽

Endothelial Permeability ◽

Receptor Potential ◽

Trpc Channels ◽

Dependent Manner ◽

Barrier Dysfunction ◽

Barrier Disruption ◽

Transient Receptor ◽

Lung Vascular Permeability

Lung vascular endothelial barrier disruption and the accompanying inflammation are primary pathogenic features of acute lung injury (ALI); however, the basis for the development of both remains unclear. Studies have shown that activation of transient receptor potential canonical (TRPC) channels induces Ca2+ entry, which is essential for increased endothelial permeability. Here, we addressed the role of Toll-like receptor 4 (TLR4) intersection with TRPC6-dependent Ca2+ signaling in endothelial cells (ECs) in mediating lung vascular leakage and inflammation. We find that the endotoxin (lipopolysaccharide; LPS) induces Ca2+ entry in ECs in a TLR4-dependent manner. Moreover, deletion of TRPC6 renders mice resistant to endotoxin-induced barrier dysfunction and inflammation, and protects against sepsis-induced lethality. TRPC6 induces Ca2+ entry in ECs, which is secondary to the generation of diacylglycerol (DAG) induced by LPS. Ca2+ entry mediated by TRPC6, in turn, activates the nonmuscle myosin light chain kinase (MYLK), which not only increases lung vascular permeability but also serves as a scaffold to promote the interaction of myeloid differentiation factor 88 and IL-1R–associated kinase 4, which are required for NF-κB activation and lung inflammation. Our findings suggest that TRPC6-dependent Ca2+ entry into ECs, secondary to TLR4-induced DAG generation, participates in mediating both lung vascular barrier disruption and inflammation induced by endotoxin.

Download Full-text

Exploring Morphine-Triggered PKC-Targets and Their Interaction with Signaling Pathways Leading to Pain via TrkA

Proteomes ◽

10.3390/proteomes6040039 ◽

2018 ◽

Vol 6 (4) ◽

pp. 39 ◽

Cited By ~ 3

Author(s):

Darlene A. Pena ◽

Mariana Lemos Duarte ◽

Dimitrius T. Pramio ◽

Lakshmi A. Devi ◽

Deborah Schechtman

Keyword(s):

Transient Receptor Potential ◽

Receptor Potential ◽

Morphine Tolerance ◽

Dependent Manner ◽

Receptor Desensitization ◽

Kinase Activation ◽

Protein Receptor ◽

Opiate Tolerance ◽

Transient Receptor

It is well accepted that treatment of chronic pain with morphine leads to μ opioid receptor (MOR) desensitization and the development of morphine tolerance. MOR activation by the selective peptide agonist, D-Ala2, N-MePhe4, Gly-ol]-enkephalin(DAMGO), leads to robust G protein receptor kinase activation, β-arrestin recruitment, and subsequent receptor endocytosis, which does not occur in an activation by morphine. However, MOR activation by morphine induces receptor desensitization, in a Protein kinase C (PKC) dependent manner. PKC inhibitors have been reported to decrease receptor desensitization, reduce opiate tolerance, and increase analgesia. However, the exact role of PKC in these processes is not clearly delineated. The difficulties in establishing a particular role for PKC have been, in part, due to the lack of reagents that allow the selective identification of PKC targets. Recently, we generated a conformation state-specific anti-PKC antibody that preferentially recognizes the active state of this kinase. Using this antibody to selectively isolate PKC substrates and a proteomics strategy to establish the identity of the proteins, we examined the effect of morphine treatment on the PKC targets. We found an enhanced interaction of a number of proteins with active PKC, in the presence of morphine. In this article, we discuss the role of these proteins in PKC-mediated MOR desensitization and analgesia. In addition, we posit a role for some of these proteins in mediating pain by TrKA activation, via the activation of transient receptor potential cation channel subfamily V member 1 (TRPV1). Finally, we discuss how these new PKC interacting proteins and pathways could be targeted for the treatment of pain.

Download Full-text