Publications by authors named "Gerald W Zamponi"

278 Publications

Trigeminal neuropathic pain causes changes in affective processing of pain in rats.

Mol Pain 2022 Jan-Dec;18:17448069211057750

Department of Pharmacology, Biological Sciences Building, 232174Federal University of Parana, Curitiba, Brazil.

Trigeminal neuropathic pain has been modeled in rodents through the constriction of the infraorbital nerve (CCI-ION). Sensory alterations, including spontaneous pain, and thermal and mechanical hyperalgesia are well characterized, but there is a notable lack of evidence about the affective pain component in this model. Evaluation of the emotional component of pain in rats has been proposed as a way to optimize potential translational value of non-clinical studies. In rats, 22 and 50 kHz ultrasonic vocalizations (USVs) are considered well-established measures of negative and positive emotional states, respectively. Thus, this study tested the hypothesis that trigeminal neuropathic pain would result, in addition to the sensory alterations, in a decrease of 50 kHz USV, which may be related to altered function of brain areas involved in emotional pain processing. CCI-ION surgery was performed on 60-day-old male Wistar rats. 15 days after surgery, von Frey filaments were applied to detect mechanical hyperalgesia, and USV was recorded. At the same timepoint, systemic treatment with d,l-amphetamine (1 mg/kg) allowed investigation of the involvement of the dopaminergic system in USV emission. Finally, brain tissue was collected to assess the change in tyrosine hydroxylase (TH) expression in the nucleus accumbens (NAc) and c-Fos expression in brain areas involved in emotional pain processing, including the prefrontal cortex (PFC), amygdala, and NAc. The results showed that CCI-ION rats presented mechanical hyperalgesia and a significant reduction of environmental-induced 50 kHz USV. Amphetamine caused a marked increase in 50 kHz USV emission in CCI-ION rats. In addition, TH expression was lower in constricted animals and c-Fos analysis revealed an increase in neuronal activation. Taken together, these data indicate that CCI-ION causes a reduction in the emission of environmental-induced appetitive calls concomitantly with facial mechanical hyperalgesia and that both changes may be related to a reduction in the mesolimbic dopaminergic activity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/17448069211057750DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8777332PMC
January 2022

Gut-innoervating TRPV1+ Neurons Drive Chronic Visceral Pain via Microglial P2Y12 Receptor.

Cell Mol Gastroenterol Hepatol 2021 Dec 24. Epub 2021 Dec 24.

Department of Physiology and Pharmacology, Calgary, Alberta, Canada; Inflammation Research Network-Snyder Institute for Chronic Diseases, Calgary, Alberta, Canada; Alberta Children's Hospital Research Institute, Cumming School of Medicine, Calgary, Alberta, Canada. Electronic address:

Background & Aims: Chronic abdominal pain is a common symptom of inflammatory bowel diseases (IBDs). Peripheral and central mechanisms contribute to the transition from acute to chronic pain during active disease and clinical remission. Lower mechanical threshold and hyperexcitability of visceral afferents induce gliosis in central pain circuits, leading to persistent visceral hypersensitivity (VHS). In the spinal cord, microglia, the immune sentinels of the central nervous system, undergo activation in multiple models of VHS. Here, we investigated the mechanisms of microglia activation to identify centrally acting analgesics for chronic IBD pain.

Methods: Using Designer Receptors Exclusively Activated by Designer Drugs (DREADD) expressed in transient receptor potential vanilloid member 1-expressing visceral neurons that sense colonic inflammation, we tested whether neuronal activity was indispensable to control microglia activation and VHS. We then investigated the neuron-microglia signaling system involved in visceral pain chronification.

Results: We found that chemogenetic inhibition of transient receptor potential vanilloid member 1 visceral afferents prevents microglial activation in the spinal cord and subsequent VHS in colitis mice. In contrast, chemogenetic activation, in the absence of colitis, enhanced microglial activation associated with VHS. We identified a purinergic signaling mechanism mediated by neuronal adenosine triphosphate and microglial P2RY12 receptor, triggering VHS in colitis. Inhibition of P2RY12 prevented microglial reactivity and chronic VHS post-colitis.

Conclusions: Overall, these data provide novel insights into the central mechanisms of chronic visceral pain and suggest that targeting microglial P2RY12 signaling could be harnessed to relieve pain in patients with IBD who are in remission.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jcmgh.2021.12.012DOI Listing
December 2021

The terpenes camphene and alpha-bisabolol inhibit inflammatory and neuropathic pain via Cav3.2 T-type calcium channels.

Mol Brain 2021 11 14;14(1):166. Epub 2021 Nov 14.

Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, University of Calgary, AB, T2N 4N1, Calgary, Canada.

T-type calcium channels are known molecular targets of certain phytocannabinoids and endocannabinoids. Here we explored the modulation of Cav3.2 T-type calcium channels by terpenes derived from cannabis plants. A screen of eight commercially available terpenes revealed that camphene and alpha-bisabolol mediated partial, but significant inhibition of Cav3.2 channels expressed in tsA-201 cells, as well as native T-type channels in mouse dorsal root ganglion neurons. Both compounds inhibited peak current amplitude with IC50s in the low micromolar range, and mediated an additional small hyperpolarizing shift in half-inactivation voltage. When delivered intrathecally, both terpenes inhibited nocifensive responses in mice that had received an intraplantar injection of formalin, with alpha-bisabolol showing greater efficacy. Both terpenes reduced thermal hyperalgesia in mice injected with Complete Freund's adjuvant. This effect was independent of sex, and absent in Cav3.2 null mice, indicating that these compounds mediate their analgesic properties by acting on Cav3.2 channels. Both compounds also inhibited mechanical hypersensitivity in a mouse model of neuropathic pain. Hence, camphene and alpha-bisabolol have a wide spectrum of analgesic action by virtue of inhibiting Cav3.2 T-type calcium channels.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13041-021-00876-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8591808PMC
November 2021

Correction to: Regulation of Ca3.2 channels by the receptor for activated C kinase 1 (Rack-1).

Pflugers Arch 2021 Oct 21. Epub 2021 Oct 21.

Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00424-021-02633-zDOI Listing
October 2021

Regulation of Ca3.2 channels by the receptor for activated C kinase 1 (Rack-1).

Pflugers Arch 2021 Oct 8. Epub 2021 Oct 8.

Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada.

This study describes the interaction between Ca3.2 calcium channels and the receptor for activated C kinase 1 (Rack-1), a scaffold protein which has recently been implicated in neuropathic pain. The coexpression of Ca3.2 and Rack-1 in tsA-201 cells led to a reduction in the magnitude of whole-cell Ca3.2 currents and Ca3.2 channel expression at the plasma membrane. Co-immunoprecipitations from transfected cells show the formation of a molecular protein complex between Cav3.2 channels and Rack-1. We determined that the interaction of Rack-1 occurs at the intracellular II-III loop and the C-terminus of the channel. Finally, the coexpression of PKCβII abolished the effect of Rack-1 on current densities. Altogether, our findings show that Rack-1 regulates Ca3.2-mediated calcium entry in a PKC-dependent manner.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00424-021-02631-1DOI Listing
October 2021

Splice-variant specific effects of a CACNA1H mutation associated with writer's cramp.

Mol Brain 2021 09 20;14(1):145. Epub 2021 Sep 20.

Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, Alberta Children's Hospital Research Institute,, University of Calgary, Alberta, Calgary, Canada.

The CACNA1H gene encodes the α1 subunit of the low voltage-activated Ca3.2 T-type calcium channel, an important regulator of neuronal excitability. Alternative mRNA splicing can generate multiple channel variants with distinct biophysical properties and expression patterns. Two major splice variants, containing or lacking exon 26 (± 26) have been found in different human tissues. In this study, we report splice variant specific effects of a Ca3.2 mutation found in patients with autosomal dominant writer's cramp, a specific type of focal dystonia. We had previously reported that the R481C missense mutation caused a gain of function effect when expressed in Ca3.2 (+ 26) by accelerating its recovery from inactivation. Here, we show that when the mutation is expressed in the short variant of the channel (- 26), we observe a significant increase in current density when compared to wild-type Ca3.2 (- 26) but the effect on the recovery from inactivation is lost. Our data add to growing evidence that the functional expression of calcium channel mutations depends on which splice variant is being examined.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13041-021-00861-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8451114PMC
September 2021

Structural optimization, synthesis and in vitro synergistic anticancer activities of combinations of new N3-substituted dihydropyrimidine calcium channel blockers with cisplatin and etoposide.

Bioorg Chem 2021 10 11;115:105262. Epub 2021 Aug 11.

Department of Pharmaceutical Sciences, College of Pharmacy & Allied Health Sciences, South Dakota State University, Brookings, SD 57006, USA. Electronic address:

T-type calcium channels are considered potential drug targets to combat cancer. Combining T-type calcium channel blockers with conventional chemotherapy drugs represents a promising strategy towards successful cancer treatment. From this perspective, we report in this study the design and synthesis of a novel series of N3-sustituted dihydropyrimidines (DHPMs) as anticancer adjuvants to cisplatin (Cis) and etoposide (Eto). Full spectral characterization of the new compounds was done using FT-IR, H NMR, C NMR, and HRMS. Structure elucidation was confirmed by 2D NMR H-H COSY, HSQC and NOESY experiments. Novel derivatives were tested for their Ca channel blocking activity by employing the whole cell patch-clamp technique. Results demonstrated that most compounds were potential T-type calcium channel blockers with the triazole-based C12 and C13 being the most selective agents against Ca3.2 channel. Further electrophysiological studies demonstrated that C12 and C13 inhibited Ca3.2 currents with respective affinity of 2.26 and 1.27 µM, and induced 5 mV hyperpolarizing shifts in the half-inactivation potential. Subsequently, C12 and C13 were evaluated for their anticancer activities alone and in combination with Cis and Eto against A549 and MDA-MB 231 cancer cells. Interestingly, both compounds exhibited potential anticancer effects with IC values < 5 µM. Combination studies revealed that both compounds had synergistic effects (combination index CI < 1) on Cis and Eto through induction of apoptosis (p53 activation and up-regulation of BAX and p21 gene expression). Importantly, in silico physicochemical and ADMET assessment of both compounds revealed their potential drug-like properties with decreased risk of cardiac toxicity. Hence, C12 and C13 are promising anticancer adjuvants through inhibition of Ca3.2 T-type calcium channels, thereby serving as eminent leads for further modification.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bioorg.2021.105262DOI Listing
October 2021

De novo SCN8A and inherited rare CACNA1H variants associated with severe developmental and epileptic encephalopathy.

Mol Brain 2021 08 16;14(1):126. Epub 2021 Aug 16.

Department of Pathophysiology, Third Faculty of Medicine, Charles University, Prague, Czech Republic.

Developmental and epileptic encephalopathies (DEEs) are a group of severe epilepsies that are characterized by seizures and developmental delay. DEEs are primarily attributed to genetic causes and an increasing number of cases have been correlated with variants in ion channel genes. In this study, we report a child with an early severe DEE. Whole exome sequencing showed a de novo heterozygous variant (c.4873-4881 duplication) in the SCN8A gene and an inherited heterozygous variant (c.952G > A) in the CACNA1H gene encoding for Na1.6 voltage-gated sodium and Ca3.2 voltage-gated calcium channels, respectively. In vitro functional analysis of human Na1.6 and Ca3.2 channel variants revealed mild but significant alterations of their gating properties that were in general consistent with a gain- and loss-of-channel function, respectively. Although additional studies will be required to confirm the actual pathogenic involvement of SCN8A and CACNA1H, these findings add to the notion that rare ion channel variants may contribute to the etiology of DEEs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13041-021-00838-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8365958PMC
August 2021

Protocol for detecting plastic changes in defined neuronal populations in neuropathic mice.

STAR Protoc 2021 Sep 26;2(3):100698. Epub 2021 Jul 26.

Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada.

Characterization of synaptic plasticity changes via optogenetic manipulation between defined neuronal populations is important for mapping neural circuits involved in normal brain functions and disorders such as neuropathic pain. However, determining the strength of synaptic transmission based on optogenetic manipulation is challenging due to variability in opsin expression. This protocol describes the use of slice electrophysiology combined with optogenetics to examine synaptic transmission in genetically defined neuronal populations from neuropathic mice. We detail surgical procedures of spared nerve injury for inducing neuropathy. For complete details on the use and execution of this protocol, please refer to Huang et al. (2019) and Huang et al. (2021).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.xpro.2021.100698DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8333107PMC
September 2021

Mutation of copper binding sites on cellular prion protein abolishes its inhibitory action on NMDA receptors in mouse hippocampal neurons.

Mol Brain 2021 07 19;14(1):117. Epub 2021 Jul 19.

Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, T2N 4N1, Canada.

We have previously reported that cellular prion protein (PrP) can down-regulate NMDA receptor activity and in a copper dependent manner. Here, we employed AAV9 to introduce murine cellular prion protein into mouse hippocampal neurons in primary cultures from PrP null mice to determine the role of the six copper binding motifs located within the N-terminal domain of PrP. The results demonstrate that viral expression of wild type PrP lowers NMDAR activity in PrP null mouse hippocampal neurons by reducing the magnitude of non-desensitizing currents. Elimination of the last two copper binding sites alone, or in combination with the remaining four attenuates this protective effect. Thus our data suggest that copper ion interactions with specific binding sites on PrP are critical for PrP dependent modulation of NMDA receptor function.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13041-021-00828-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8287767PMC
July 2021

Modeling temperature- and Cav3 subtype-dependent alterations in T-type calcium channel mediated burst firing.

Mol Brain 2021 07 17;14(1):115. Epub 2021 Jul 17.

Department of Cell Biology and Anatomy, Cumming School of Medicine University of Calgary, Calgary, Canada.

T-type calcium channels are important regulators of neuronal excitability. The mammalian brain expresses three T-type channel isoforms (Cav3.1, Cav3.2 and Cav3.3) with distinct biophysical properties that are critically regulated by temperature. Here, we test the effects of how temperature affects spike output in a reduced firing neuron model expressing specific Cav3 channel isoforms. The modeling data revealed only a minimal effect on baseline spontaneous firing near rest, but a dramatic increase in rebound burst discharge frequency for Cav3.1 compared to Cav3.2 or Cav3.3 due to differences in window current or activation/recovery time constants. The reduced response by Cav3.2 could optimize its activity where it is expressed in peripheral tissues more subject to temperature variations than Cav3.1 or Cav3.3 channels expressed prominently in the brain. These tests thus reveal that aspects of neuronal firing behavior are critically dependent on both temperature and T-type calcium channel subtype.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13041-021-00813-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8285791PMC
July 2021

SUMO wrestling in the cellular dohyō: crosstalk between phosphorylation and SUMOylation of PKCδ regulates oxidative cell damage.

Authors:
Gerald W Zamponi

FEBS J 2021 11 1;288(22):6406-6409. Epub 2021 Jul 1.

Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, University of Calgary, Canada.

The novel PKCδ isoform has been shown to mediate a pro-apoptotic function in response to oxidative stressors. Siman Gao and colleagues performed an in-depth biochemical and molecular analysis of factors that regulate PKCδ function. They demonstrated convincingly that PKCδ is regulated by an interplay between SUMOylation and phosphorylation. They also showed that these events are critical for hydrogen peroxide induced apoptosis, thus identifying potentially novel mechanisms that may be harnessed for cell protection. Comment on: https://doi.org/10.1111/febs.16050.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/febs.16028DOI Listing
November 2021

An orbitofrontal cortex to midbrain projection modulates hypersensitivity after peripheral nerve injury.

Cell Rep 2021 04;35(4):109033

Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada. Electronic address:

Neuropathic pain is a debilitating condition that is often refractory to treatment. The network of neural substrates for pain transmission and control within the brain is complex and remains poorly understood. Through a combination of neuronal tracing, optogenetics, chemogenetics, electrophysiological recordings, and behavioral assessment, we demonstrate that activation of layer 5 pyramidal neurons in the ventrolateral orbitofrontal cortex (vlOFC) attenuates mechanical and thermal hypersensitivity and cold allodynia in mice with neuropathic pain induced by spared nerve injury (SNI). These vlOFC output neurons project to the posterior ventrolateral periaqueductal gray (vlPAG) region and receive inputs from the ventromedial thalamus (VM). Specific optogenetic and chemogenetic activation of the vlOFC-vlPAG and the VM-vlOFC circuits inhibits hypersensitivity associated with neuropathy. Thus, we reveal a modulatory role of the vlOFC and its projections to the vlPAG circuit in the processing of hypersensitive nociception.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.celrep.2021.109033DOI Listing
April 2021

Synthesis and Biological Evaluation of Novel Benzhydrylpiperazine-Coupled Nitrobenzenesulfonamide Hybrids.

ACS Omega 2021 Apr 31;6(14):9731-9740. Epub 2021 Mar 31.

Centre for Organic and Medicinal Chemistry, Department of Chemistry, School of Advanced Sciences, VIT University, Vellore, Tamil Nadu 632014, India.

A series of novel benzhydryl piperazine-coupled nitrobenzenesulfonamide hybrids were synthesized with good to excellent yields. They were tested for inhibition of mycobacterial activity against the H37Rv strain, cytotoxicity MTT (RAW 264.7cells) assay, nutrient starvation (H37Rv strain), and ability to block Cav3.2 T-type calcium channels. Novel hybrids did not inhibit T-type calcium channels, whereas they showed excellent antituberculosis (TB) activity and low cytotoxicity with a selectivity index of >30. A direct impact of the amino acid linker was not observed. Studied hybrids exhibited good inhibition activities, and the 2,4-dinitrobenzenesulfonamide group emerged as a promising scaffold for further drug design by hybridization approaches for anti-TB therapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsomega.1c00369DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8047747PMC
April 2021

The life cycle of voltage-gated Ca channels in neurons: an update on the trafficking of neuronal calcium channels.

Neuronal Signal 2021 Apr 23;5(1):NS20200095. Epub 2021 Feb 23.

Department of Physiology and Pharmacology, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.

Neuronal voltage-gated Ca (Ca) channels play a critical role in cellular excitability, synaptic transmission, excitation-transcription coupling and activation of intracellular signaling pathways. Ca channels are multiprotein complexes and their functional expression in the plasma membrane involves finely tuned mechanisms, including forward trafficking from the endoplasmic reticulum (ER) to the plasma membrane, endocytosis and recycling. Whether genetic or acquired, alterations and defects in the trafficking of neuronal Ca channels can have severe physiological consequences. In this review, we address the current evidence concerning the regulatory mechanisms which underlie precise control of neuronal Ca channel trafficking and we discuss their potential as therapeutic targets.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1042/NS20200095DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7905535PMC
April 2021

Ethosuximide inhibits acute histamine- and chloroquine-induced scratching behavior in mice.

Mol Brain 2021 03 2;14(1):46. Epub 2021 Mar 2.

Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.

We have recently reported that the Cav3.2 T-type calcium channel which is well known for its key role in pain signalling, also mediates a critical function in the transmission of itch/pruritus. Here, we evaluated the effect of the clinically used anti-seizure medication ethosuximide, a well known inhibitor of T-type calcium channels, on male and female mice subjected to histaminergic- and non-histaminergic itch. When delivered intraperitoneally ethosuximide significantly reduced scratching behavior of mice of both sexes in response to subcutaneous injection of either histamine or chloroquine. When co-delivered subcutaneously together with either pruritogenic agent ethosuximide was also effective in inhibiting scratching responses in both male and female animals. Overall, our results are consistent with an important role of Cav3.2 T-type calcium channels in modulating histamine-dependent and histamine-independent itch transmission in the primary sensory pathway. Our findings also suggest that ethosuximide could be explored further as a possible therapeutic for the treatment of itch.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13041-021-00762-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7927410PMC
March 2021

The IL33 receptor ST2 contributes to mechanical hypersensitivity in mice with neuropathic pain.

Mol Brain 2021 02 17;14(1):35. Epub 2021 Feb 17.

Department of Physiology and Pharmacology, Cumming School of Medicine, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada.

Pathogen infection triggers pain via activation of the innate immune system. Toll-like receptors (TLRs) and Nod-like receptors (NLRs) are the main components of innate immunity and have been implicated in pain signaling. We previously revealed that the TLR2-NLRP3-IL33 pathway mediates inflammatory pain responses during hyperactivity of innate immunity. However, their roles in neuropathic pain had remained unclear. Here we report that although knockout of TLR2 or NLRP3 does not affect spared nerve injury (SNI)-induced neuropathic pain, intrathecal inhibition of IL33/ST2 signaling with ST2 neutralizing antibodies reverses mechanical thresholds in SNI mice compared to PBS vehicle treated animals. This effect indicates a universal role of IL33 in both inflammatory and neuropathic pain states, and that targeting the IL33/ST2 axis could be a potential therapeutic approach for pain treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13041-021-00752-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7888111PMC
February 2021

Voltage-gated calcium channel nanodomains: molecular composition and function.

FEBS J 2021 Feb 11. Epub 2021 Feb 11.

Department of Physiology and Pharmacology, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, AB, Canada.

Voltage-gated calcium (Ca ) channels and their regulation by proteins at the synaptic cleft play a critical role in neurotransmission. These interactions fine-tune the synaptic response through the regulation of Ca entry into the presynaptic terminal and trigger the fusion of vesicles filled with neurotransmitters and peptides. Regulation of Ca channel intrinsic properties and their numbers at the active zones shape the timing and strength of synaptic function. Here, we provide an overview of a number of proteins reported to be part of Ca channel nanodomains at the synaptic cleft and the repercussions of these interactions for Ca channel trafficking, tethering at the active zone, and regulation of their biophysical properties. We summarize the current state of knowledge by which Ca channels are regulated at presynaptic sites.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/febs.15759DOI Listing
February 2021

The de novo CACNA1A pathogenic variant Y1384C associated with hemiplegic migraine, early onset cerebellar atrophy and developmental delay leads to a loss of Cav2.1 channel function.

Mol Brain 2021 02 8;14(1):27. Epub 2021 Feb 8.

Department of Physiology and Pharmacology, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.

CACNA1A pathogenic variants have been linked to several neurological disorders including familial hemiplegic migraine and cerebellar conditions. More recently, de novo variants have been associated with severe early onset developmental encephalopathies. CACNA1A is highly expressed in the central nervous system and encodes the pore-forming Caα subunit of P/Q-type (Cav2.1) calcium channels. We have previously identified a patient with a de novo missense mutation in CACNA1A (p.Y1384C), characterized by hemiplegic migraine, cerebellar atrophy and developmental delay. The mutation is located at the transmembrane S5 segment of the third domain. Functional analysis in two predominant splice variants of the neuronal Cav2.1 channel showed a significant loss of function in current density and changes in gating properties. Moreover, Y1384 variants exhibit differential splice variant-specific effects on recovery from inactivation. Finally, structural analysis revealed structural damage caused by the tyrosine substitution and changes in electrostatic potentials.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13041-021-00745-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7871581PMC
February 2021

Rare functional missense variants in CACNA1H: What can we learn from Writer's cramp?

Mol Brain 2021 01 21;14(1):18. Epub 2021 Jan 21.

Department of Genetics, University Medical Center Groningen, University of Groningen, P.O. box 30 001, 9700 RB, Groningen, The Netherlands.

Writer's cramp (WC) is a task-specific focal dystonia that occurs selectively in the hand and arm during writing. Previous studies have shown a role for genetics in the pathology of task-specific focal dystonia. However, to date, no causal gene has been reported for task-specific focal dystonia, including WC. In this study, we investigated the genetic background of a large Dutch family with autosomal dominant‒inherited WC that was negative for mutations in known dystonia genes. Whole exome sequencing identified 4 rare variants of unknown significance that segregated in the family. One candidate gene was selected for follow-up, Calcium Voltage-Gated Channel Subunit Alpha1 H, CACNA1H, due to its links with the known dystonia gene Potassium Channel Tetramerization Domain Containing 17, KCTD17, and with paroxysmal movement disorders. Targeted resequencing of CACNA1H in 82 WC cases identified another rare, putative damaging variant in a familial WC case that did not segregate. Using structural modelling and functional studies in vitro, we show that both the segregating p.Arg481Cys variant and the non-segregating p.Glu1881Lys variant very likely cause structural changes to the Cav3.2 protein and lead to similar gains of function, as seen in an accelerated recovery from inactivation. Both mutant channels are thus available for re-activation earlier, which may lead to an increase in intracellular calcium and increased neuronal excitability. Overall, we conclude that rare functional variants in CACNA1H need to be interpreted very carefully, and additional studies are needed to prove that the p.Arg481Cys variant is the cause of WC in the large Dutch family.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13041-021-00736-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7819179PMC
January 2021

A CACNA1A variant associated with trigeminal neuralgia alters the gating of Cav2.1 channels.

Mol Brain 2021 01 7;14(1). Epub 2021 Jan 7.

Department of Physiology and Pharmacology, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada.

A novel missense mutation in the CACNA1A gene that encodes the pore forming α subunit of the Ca2.1 voltage-gated calcium channel was identified in a patient with trigeminal neuralgia. This mutation leads to a substitution of proline 2455 by histidine (P2455H) in the distal C-terminus region of the channel. Due to the well characterized role of this channel in neurotransmitter release, our aim was to characterize the biophysical properties of the P2455H variant in heterologously expressed Ca2.1 channels. Whole-cell patch clamp recordings of wild type and mutant Ca2.1 channels expressed in tsA-201 cells reveal that the mutation mediates a depolarizing shift in the voltage-dependence of activation and inactivation. Moreover, the P2455H mutant strongly reduced calcium-dependent inactivation of the channel that is consistent with an overall gain of function. Hence, the P2455H Ca2.1 missense mutation alters the gating properties of the channel, suggesting that associated changes in Ca2.1-dependent synaptic communication in the trigeminal system may contribute to the development of trigeminal neuralgia.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13041-020-00725-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7789175PMC
January 2021

Functional identification of potential non-canonical N-glycosylation sites within Ca3.2 T-type calcium channels.

Mol Brain 2020 11 11;13(1):149. Epub 2020 Nov 11.

Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University, Prague, Czech Republic.

Low-voltage-activated T-type calcium channels are important contributors to nervous system function. Post-translational modification of these channels has emerged as an important mechanism to control channel activity. Previous studies have documented the importance of asparagine (N)-linked glycosylation and identified several asparagine residues within the canonical consensus sequence N-X-S/T that is essential for the expression and function of Ca3.2 channels. Here, we explored the functional role of non-canonical N-glycosylation motifs in the conformation N-X-C based on site directed mutagenesis. Using a combination of electrophysiological recordings and surface biotinylation assays, we show that asparagines N345 and N1780 located in the motifs NVC and NPC, respectively, are essential for the expression of the human Ca3.2 channel in the plasma membrane. Therefore, these newly identified asparagine residues within non-canonical motifs add to those previously reported in canonical sites and suggest that N-glycosylation of Ca3.2 may also occur at non-canonical motifs to control expression of the channel in the plasma membrane. It is also the first study to report the functional importance of non-canonical N-glycosylation motifs in an ion channel.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13041-020-00697-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7659234PMC
November 2020

Hyperactivity of Innate Immunity Triggers Pain via TLR2-IL-33-Mediated Neuroimmune Crosstalk.

Cell Rep 2020 10;33(1):108233

Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada. Electronic address:

The innate immune system responds to infections that give rise to pain. How the innate immune system interacts with the sensory nervous system and contributes to pain is poorly understood. Here we report that hyperactivity of innate immunity primes and initiates pain states via the TLR2-interleukin-33 (IL-33) axis. Toll-like receptors (TLRs) are upregulated in the complete Freund's adjuvant (CFA) pain model, and knockout of TLR2 abolishes CFA-induced pain. Selective activation of TLR2/6 triggers acute pain via upregulation of IL-33 in the hindpaw, dorsal root ganglia (DRG), and spinal cord in an NLRP3-dependent manner. The IL-33 increase further initiates priming of nociceptive neurons and pain states. Finally, blocking IL-33 receptors at the spinal level mediates analgesia during acute and chronic inflammatory pain, underscoring an important function of IL-33 in pain signaling. Collectively, our data reveal a critical role of the TLR2-IL-33 axis in innate immune activation for pain initiation and maintenance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.celrep.2020.108233DOI Listing
October 2020

Cav3.2 T-type calcium channels control acute itch in mice.

Mol Brain 2020 09 1;13(1):119. Epub 2020 Sep 1.

Department of Physiology and Pharmacology Hotchkiss Brain Institute, Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.

Cav3.2 T-type calcium channels are important mediators of nociceptive signaling, but their roles in the transmission of itch remains poorly understood. Here we report a key involvement of these channels as key modulators of itch/pruritus-related behavior. We compared scratching behavior responses between wild type and Cav3.2 null mice in models of histamine- or chloroquine-induced itch. We also evaluated the effect of the T-type calcium channel blocker DX332 in male and female wild-type mice injected with either histamine or chloroquine. Cav3.2 null mice exhibited decreased scratching responses during both histamine- and chloroquine-induced acute itch. DX332 co-injected with the pruritogens inhibited scratching responses of male and female mice treated with either histamine or chloroquine. Altogether, our data provide strong evidence that Cav3.2 T-type channels exert an important role in modulating histamine-dependent and -independent itch transmission in the primary sensory afferent pathway, and highlight these channels as potential pharmacological targets to treat pruritus.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13041-020-00663-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7465799PMC
September 2020

Dopamine Inputs from the Ventral Tegmental Area into the Medial Prefrontal Cortex Modulate Neuropathic Pain-Associated Behaviors in Mice.

Cell Rep 2020 06;31(12):107812

Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada. Electronic address:

The medial prefrontal cortex (mPFC) is a brain region involved in the affective components of pain and undergoes plasticity during the development of chronic pain. Dopamine (DA) is a key neuromodulator in the mesocortical circuit and modulates working memory and aversion. Although DA inputs into the mPFC are known to modulate plasticity, whether and how these inputs affect pain remains incompletely understood. By using optogenetics, we find that phasic activation of DA inputs from the ventral tegmental area (VTA) into the mPFC reduce mechanical hypersensitivity during neuropathic pain states. Mice with neuropathic pain exhibit a preference for contexts paired with photostimulation of DA terminals in the mPFC. Fiber photometry-based calcium imaging reveals that DA increases the activity of mPFC neurons projecting to the ventrolateral periaqueductal gray (vlPAG). Together, our findings indicate an important role of mPFC DA signaling in pain modulation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.celrep.2020.107812DOI Listing
June 2020

Acute orofacial pain leads to prolonged changes in behavioral and affective pain components.

Pain 2020 12;161(12):2830-2840

Department of Pharmacology, Biological Sciences Building, Federal University of Parana, Curitiba, Paraná, Brazil.

Acute pain that persists for a few days is associated with a reduction in patients' quality of life. Orofacial persistent pain promotes psychological disorders such as anxiety, impairs daily essential activities such as eating, and results in decreased social interaction. Here, we investigated whether rats subjected to orofacial formalin injection or intraoral incision surgery display persistent facial heat hyperalgesia, ongoing pain, anxiety-like behavior, and changes in ultrasonic vocalization. Orofacial formalin injection or intraoral incision caused facial heat hyperalgesia for 3 days compared with saline-injected and sham animals. In addition, both experimental groups showed a reduction in the number of entries and in the time spent in the open arms in the elevated plus maze test on day 3, suggesting that anxiety-like behavior developed as a consequence of persistent pain. At this time point, both groups also displayed a reduction in the number of 50-kHz calls, specifically in the flat subtype, which suggests a decrease in social communication. Moreover, on day 3 after surgery, systemic morphine produced robust conditioned place preference in rats subjected to intraoral incision compared with sham, and the former group also presented increased spontaneous facial grooming, revealing the presence of ongoing pain. Finally, Western blot and immunohistochemistry analysis showed a reduction in tyrosine hydroxylase expression in the nucleus accumbens, which may reflect a decrease in mesolimbic dopaminergic activity. Altogether, the results demonstrate that acute orofacial pain causes prolonged changes in behavioral and affective pain components, which may be related to dopaminergic changes in the nucleus accumbens.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/j.pain.0000000000001970DOI Listing
December 2020

Opioid Receptor Regulation of Neuronal Voltage-Gated Calcium Channels.

Cell Mol Neurobiol 2021 Jul 8;41(5):839-847. Epub 2020 Jun 8.

Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada.

Neuronal voltage-gated calcium channels play a pivotal role in the conversion of electrical signals into calcium entry into nerve endings that is required for the release of neurotransmitters. They are under the control of a number of cellular signaling pathways that serve to fine tune synaptic activities, including G-protein coupled receptors (GPCRs) and the opioid system. Besides modulating channel activity via activation of second messengers, GPCRs also physically associate with calcium channels to regulate their function and expression at the plasma membrane. In this mini review, we discuss the mechanisms by which calcium channels are regulated by classical opioid and nociceptin receptors. We highlight the importance of this regulation in the control of neuronal functions and their implication in the development of disease conditions. Finally, we present recent literature concerning the use of novel μ-opioid receptor/nociceptin receptor modulators and discuss their use as potential drug candidates for the treatment of pain.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10571-020-00894-3DOI Listing
July 2021

FMRP(1-297)-tat restores ion channel and synaptic function in a model of Fragile X syndrome.

Nat Commun 2020 06 2;11(1):2755. Epub 2020 Jun 2.

Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada.

Fragile X Syndrome results from a loss of Fragile X Mental Retardation Protein (FMRP). We now show that FMRP is a member of a Cav3-Kv4 ion channel complex that is known to regulate A-type potassium current in cerebellar granule cells to produce mossy fiber LTP. Mossy fiber LTP is absent in Fmr1 knockout (KO) mice but is restored by FMRP(1-297)-tat peptide. This peptide further rapidly permeates the blood-brain barrier to enter cells across the cerebellar-cortical axis that restores the balance of protein translation for at least 24 h and transiently reduces elevated levels of activity of adult Fmr1 KO mice in the Open Field Test. These data reveal that FMRP(1-297)-tat can improve function from the levels of protein translation to synaptic efficacy and behaviour in a model of Fragile X syndrome, identifying a potential therapeutic strategy for this genetic disorder.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-020-16250-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7265297PMC
June 2020

Pain: Integration of Sensory and Affective Aspects of Pain.

Curr Biol 2020 05;30(9):R393-R395

Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr. NW, Calgary, T2N 4N1, Canada. Electronic address:

Painful stimuli are detected by peripheral nociceptors, and the brain processes this nociceptive input into an unpleasant sensation. A new study identifies a brain circuit that integrates sensory and affective aspects of inflammatory and neuropathic pain.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cub.2020.02.056DOI Listing
May 2020
-->