Molecular Mechanisms of Lipoic Acid Modulation of T-Type Calcium Channels in Pain Pathway

Alternative splicing of the skeletal muscle CaV1.1 voltage-gated calcium channel gives rise to two channel variants with very different gating properties. The currents of both channels activate slowly; however, insertion of exon 29 in the adult splice variant CaV1.1a causes an ∼30-mV right shift in the voltage dependence of activation. Existing evidence suggests that the S3–S4 linker in repeat IV (containing exon 29) regulates voltage sensitivity in this voltage-sensing domain (VSD) by modulating interactions between the adjacent transmembrane segments IVS3 and IVS4. However, activation kinetics are thought to be determined by corresponding structures in repeat I. Here, we use patch-clamp analysis of dysgenic (CaV1.1 null) myotubes reconstituted with CaV1.1 mutants and chimeras to identify the specific roles of these regions in regulating channel gating properties. Using site-directed mutagenesis, we demonstrate that the structure and/or hydrophobicity of the IVS3–S4 linker is critical for regulating voltage sensitivity in the IV VSD, but by itself cannot modulate voltage sensitivity in the I VSD. Swapping sequence domains between the I and the IV VSDs reveals that IVS4 plus the IVS3–S4 linker is sufficient to confer CaV1.1a-like voltage dependence to the I VSD and that the IS3–S4 linker plus IS4 is sufficient to transfer CaV1.1e-like voltage dependence to the IV VSD. Any mismatch of transmembrane helices S3 and S4 from the I and IV VSDs causes a right shift of voltage sensitivity, indicating that regulation of voltage sensitivity by the IVS3–S4 linker requires specific interaction of IVS4 with its corresponding IVS3 segment. In contrast, slow current kinetics are perturbed by any heterologous sequences inserted into the I VSD and cannot be transferred by moving VSD I sequences to VSD IV. Thus, CaV1.1 calcium channels are organized in a modular manner, and control of voltage sensitivity and activation kinetics is accomplished by specific molecular mechanisms within the IV and I VSDs, respectively.

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Editorial: Regulatory Action of Calcium Channels in Pain Pathway

Frontiers in Cellular Neuroscience ◽

10.3389/fncel.2021.701105 ◽

2021 ◽

Vol 15 ◽

Author(s):

Senthilkumar Rajagopal ◽

Sengottuvelan Murugan ◽

Divya P. Kumar ◽

Girish S. Kesturu ◽

Albert Baskar Arul

Keyword(s):

Calcium Channels ◽

Regulatory Action ◽

Pain Pathway

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MicroRNA-204 Is Necessary for Aldosterone-Stimulated T-Type Calcium Channel Expression in Cardiomyocytes

International Journal of Molecular Sciences ◽

10.3390/ijms19102941 ◽

2018 ◽

Vol 19 (10) ◽

pp. 2941 ◽

Cited By ~ 3

Author(s):

Riko Koyama ◽

Tiphaine Mannic ◽

Jumpei Ito ◽

Laurence Amar ◽

Maria-Christina Zennaro ◽

...

Keyword(s):

Calcium Channels ◽

Molecular Mechanisms ◽

Calcium Currents ◽

Neonatal Rat ◽

Messenger Rnas ◽

Screening Assay ◽

Rat Cardiomyocytes ◽

Ventricular Cardiomyocytes ◽

Channel Expression ◽

Beating Frequency

Activation of the mineralocorticoid receptor (MR) in the heart is considered to be a cardiovascular risk factor. MR activation leads to heart hypertrophy and arrhythmia. In ventricular cardiomyocytes, aldosterone induces a profound remodeling of ion channel expression, in particular, an increase in the expression and activity of T-type voltage-gated calcium channels (T-channels). The molecular mechanisms immediately downstream from MR activation, which lead to the increased expression of T-channels and, consecutively, to an acceleration of spontaneous cell contractions in vitro, remain poorly investigated. Here, we investigated the putative role of a specific microRNA in linking MR activation to the regulation of T-channel expression and cardiomyocyte beating frequency. A screening assay identified microRNA 204 (miR-204) as one of the major upregulated microRNAs after aldosterone stimulation of isolated neonatal rat cardiomyocytes. Aldosterone significantly increased the level of miR-204, an effect blocked by the MR antagonist spironolactone. When miR-204 was overexpressed in isolated cardiomyocytes, their spontaneous beating frequency was significantly increased after 24 h, like upon aldosterone stimulation, and messenger RNAs coding T-channels (CaV3.1 and CaV3.2) were increased. Concomitantly, T-type calcium currents were significantly increased upon miR-204 overexpression. Specifically repressing the expression of miR-204 abolished the aldosterone-induced increase of CaV3.1 and CaV3.2 mRNAs, as well as T-type calcium currents. Finally, aldosterone and miR-204 overexpression were found to reduce REST-NRSF, a known transcriptional repressor of CaV3.2 T-type calcium channels. Our study thus strongly suggests that miR-204 expression stimulated by aldosterone promotes the expression of T-channels in isolated rat ventricular cardiomyocytes, and therefore, increases the frequency of the cell spontaneous contractions, presumably through the inhibition of REST-NRSF protein.

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Free radical signalling underlies inhibition of CaV3.2 T-type calcium channels by nitrous oxide in the pain pathway

The Journal of Physiology ◽

10.1113/jphysiol.2010.196220 ◽

2010 ◽

Vol 589 (1) ◽

pp. 135-148 ◽

Cited By ~ 24

Author(s):

P. Orestes ◽

D. Bojadzic ◽

J. Lee ◽

E. Leach ◽

R. Salajegheh ◽

...

Keyword(s):

Nitrous Oxide ◽

Free Radical ◽

Calcium Channels ◽

Pain Pathway

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Inhibitory Effect of Natural Anti-Inflammatory Compounds on Cytokines Released by Chronic Venous Disease Patient-Derived Endothelial Cells

Mediators of Inflammation ◽

10.1155/2013/423407 ◽

2013 ◽

Vol 2013 ◽

pp. 1-13 ◽

Cited By ~ 5

Author(s):

Veronica Tisato ◽

Giorgio Zauli ◽

Erika Rimondi ◽

Sergio Gianesini ◽

Laura Brunelli ◽

...

Keyword(s):

Endothelial Cells ◽

Lipoic Acid ◽

Molecular Mechanisms ◽

Ex Vivo ◽

Disease Patient ◽

Therapeutic Targets ◽

Chronic Venous Disease ◽

Venous Disease ◽

Gm Csf ◽

Anti Inflammatory

Large vein endothelium plays important roles in clinical diseases such as chronic venous disease (CVD) and thrombosis; thus to characterize CVD vein endothelial cells (VEC) has a strategic role in identifying specific therapeutic targets. On these bases we evaluated the effect of the natural anti-inflammatory compoundsα-Lipoic acid and Ginkgoselect phytosome on cytokines/chemokines released by CVD patient-derived VEC. For this purpose, we characterized the levels of a panel of cytokines/chemokines (n=31) in CVD patients’ plasma compared to healthy controls and their release by VEC purified from the same patients, in unstimulated and TNF-αstimulated conditions. Among the cytokines/chemokines released by VEC, which recapitulated the systemic profile (IL-8, TNF-α, GM-CSF, INF-α2, G-CSF, MIP-1β, VEGF, EGF, Eotaxin, MCP-1, CXCL10, PDGF, and RANTES), we identified those targeted byex vivotreatment withα-Lipoic acid and/or Ginkgoselect phytosome (GM-CSF, G-CSF, CXCL10, PDGF, and RANTES). Finally, by investigating the intracellular pathways involved in promoting the VEC release of cytokines/chemokines, which are targeted by natural anti-inflammatory compounds, we documented thatα-Lipoic acid significantly counteracted TNF-α-induced NF-κB and p38/MAPK activation while the effects ofGinkgo bilobaappeared to be predominantly mediated by Akt. Ourdataprovide new insights into the molecular mechanisms of CVD pathogenesis, highlighting new potential therapeutic targets.

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Structural determinants of voltage-gating properties in calcium channels

eLife ◽

10.7554/elife.64087 ◽

2021 ◽

Vol 10 ◽

Author(s):

Monica L Fernández-Quintero ◽

Yousra El Ghaleb ◽

Petronel Tuluc ◽

Marta Campiglio ◽

Klaus R Liedl ◽

...

Keyword(s):

Calcium Channels ◽

Molecular Mechanisms ◽

Mechanistic Model ◽

Ion Pair ◽

Pair Formation ◽

Structural Determinants ◽

Voltage Sensing ◽

Voltage Gated ◽

Ion Pair Formation ◽

Activated State

Voltage-gated calcium channels control key functions of excitable cells, like synaptic transmission in neurons and the contraction of heart and skeletal muscles. To accomplish such diverse functions, different calcium channels activate at different voltages and with distinct kinetics. To identify the molecular mechanisms governing specific voltage-sensing properties we combined structure modeling, mutagenesis, and electrophysiology to analyze the structures, free energy, and transition kinetics of the activated and resting states of two functionally distinct voltage-sensing domains (VSDs) of the eukaryotic calcium channel CaV1.1. Both VSDs displayed the typical features of the sliding helix model; however, they greatly differed in ion-pair formation of the outer gating charges. Specifically, stabilization of the activated state enhanced the voltage-dependence of activation, while stabilization of resting states slowed the kinetics. This mechanism provides a mechanistic model explaining how specific ion-pair formation in separate VSDs can realize the characteristic gating properties of voltage-gated cation channels.

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Amino acid substitutions in the FXYD motif enhance phospholemman-induced modulation of cardiac L-type calcium channels

AJP Cell Physiology ◽

10.1152/ajpcell.00149.2010 ◽

2010 ◽

Vol 299 (5) ◽

pp. C1203-C1211 ◽

Cited By ~ 10

Author(s):

Kai Guo ◽

Xianming Wang ◽

Guofeng Gao ◽

Congxin Huang ◽

Keith S. Elmslie ◽

...

Keyword(s):

Amino Acid ◽

Calcium Channels ◽

Molecular Mechanisms ◽

Channel Gating ◽

Fine Tuning ◽

Amino Acid Substitutions ◽

Dependent Inactivation ◽

Voltage Dependent ◽

Kinetics Of

We have found that phospholemman (PLM) associates with and modulates the gating of cardiac L-type calcium channels (Wang et al., Biophys J 98: 1149–1159, 2010). The short 17 amino acid extracellular NH2-terminal domain of PLM contains a highly conserved PFTYD sequence that defines it as a member of the FXYD family of ion transport regulators. Although we have learned a great deal about PLM-dependent changes in calcium channel gating, little is known regarding the molecular mechanisms underlying the observed changes. Therefore, we investigated the role of the PFTYD segment in the modulation of cardiac calcium channels by individually replacing Pro-8, Phe-9, Thr-10, Tyr-11, and Asp-12 with alanine (P8A, F9A, T10A, Y11A, D12A). In addition, Asp-12 was changed to lysine (D12K) and cysteine (D12C). As expected, wild-type PLM significantly slows channel activation and deactivation and enhances voltage-dependent inactivation (VDI). We were surprised to find that amino acid substitutions at Thr-10 and Asp-12 significantly enhanced the ability of PLM to modulate CaV1.2 gating. T10A exhibited a twofold enhancement of PLM-induced slowing of activation, whereas D12K and D12C dramatically enhanced PLM-induced increase of VDI. The PLM-induced slowing of channel closing was abrogated by D12A and D12C, whereas D12K and T10A failed to impact this effect. These studies demonstrate that the PFXYD motif is not necessary for the association of PLM with CaV1.2. Instead, since altering the chemical and/or physical properties of the PFXYD segment alters the relative magnitudes of opposing PLM-induced effects on CaV1.2 channel gating, PLM appears to play an important role in fine tuning the gating kinetics of cardiac calcium channels and likely plays an important role in shaping the cardiac action potential and regulating Ca2+ dynamics in the heart.

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Molecular mechanisms of beneficial effects of lipoic acid in copper intoxicated rats assessment by FTIR and ESI-MS

Polyhedron ◽

10.1016/j.poly.2014.04.033 ◽

2014 ◽

Vol 80 ◽

pp. 223-227 ◽

Cited By ~ 6

Author(s):

Ružica S. Nikolić ◽

Nenad S. Krstić ◽

Goran M. Nikolić ◽

Gordana M. Kocić ◽

Milorad D. Cakić ◽

...

Keyword(s):

Lipoic Acid ◽

Molecular Mechanisms ◽

Esi Ms ◽

Beneficial Effects

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Apical Entry Channels in Calcium-Transporting Epithelia

Physiology ◽

10.1152/nips.01440.2003 ◽

2003 ◽

Vol 18 (4) ◽

pp. 158-163 ◽

Cited By ~ 11

Author(s):

Ji-Bin Peng ◽

Edward M. Brown ◽

Matthias A. Hediger

Keyword(s):

Vitamin D ◽

Feedback Control ◽

Calcium Channels ◽

Intracellular Calcium ◽

Calcium Transport ◽

Molecular Mechanisms ◽

Dietary Calcium ◽

Calcium Entry ◽

Rate Limiting

The identification of the apical calcium channels CaT1 and ECaC revealed the key molecular mechanisms underlying apical calcium entry in calcium-transporting epithelia. These channels are regulated directly or indirectly by vitamin D and dietary calcium and undergo feedback control by intracellular calcium, suggesting their rate-limiting roles in transcellular calcium transport.

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