Structural basis for pharmacological modulation of the TRPC6 channel

Transient receptor potential canonical (TRPC) proteins form nonselective cation channels that play physiological roles in a wide variety of cells. Despite growing evidence supporting the therapeutic potential of TRPC6 inhibition in treating pathological cardiac and renal conditions, mechanistic understanding of TRPC6 function and modulation remains obscure. Here we report cryo-EM structures of TRPC6 in both antagonist-bound and agonist-bound states. The structures reveal two novel recognition sites for the small-molecule modulators corroborated by mutagenesis data. The antagonist binds to a cytoplasm-facing pocket formed by S1-S4 and the TRP helix, whereas the agonist wedges at the subunit interface between S6 and the pore helix. Conformational changes upon ligand binding illuminate a mechanistic rationale for understanding TRPC6 modulation. Furthermore, structural and mutagenesis analyses suggest several disease-related mutations enhance channel activity by disrupting interfacial interactions. Our results provide principles of drug action that may facilitate future design of small molecules to ameliorate TRPC6-mediated diseases.

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Cannabidiol as a Potential Treatment for Anxiety and Mood Disorders: Molecular Targets and Epigenetic Insights from Preclinical Research

International Journal of Molecular Sciences ◽

10.3390/ijms22041863 ◽

2021 ◽

Vol 22 (4) ◽

pp. 1863

Author(s):

Philippe A. Melas ◽

Maria Scherma ◽

Walter Fratta ◽

Carlo Cifani ◽

Paola Fadda

Keyword(s):

Mood Disorders ◽

Cannabinoid Receptors ◽

Transient Receptor Potential ◽

Therapeutic Potential ◽

Molecular Targets ◽

Receptor Potential ◽

Transient Receptor Potential Vanilloid ◽

Preclinical Research ◽

Neuropsychiatric Diseases ◽

Transient Receptor

Cannabidiol (CBD) is the most abundant non-psychoactive component of cannabis; it displays a very low affinity for cannabinoid receptors, facilitates endocannabinoid signaling by inhibiting the hydrolysis of anandamide, and stimulates both transient receptor potential vanilloid 1 and 2 and serotonin type 1A receptors. Since CBD interacts with a wide variety of molecular targets in the brain, its therapeutic potential has been investigated in a number of neuropsychiatric diseases, including anxiety and mood disorders. Specifically, CBD has received growing attention due to its anxiolytic and antidepressant properties. As a consequence, and given its safety profile, CBD is considered a promising new agent in the treatment of anxiety and mood disorders. However, the exact molecular mechanism of action of CBD still remains unknown. In the present preclinical review, we provide a summary of animal-based studies that support the use of CBD as an anxiolytic- and antidepressant-like compound. Next, we describe neuropharmacological evidence that links the molecular pharmacology of CBD to its behavioral effects. Finally, by taking into consideration the effects of CBD on DNA methylation, histone modifications, and microRNAs, we elaborate on the putative role of epigenetic mechanisms in mediating CBD’s therapeutic outcomes.

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Carvacrol Attenuates Hippocampal Neuronal Death after Global Cerebral Ischemia via Inhibition of Transient Receptor Potential Melastatin 7

Cells ◽

10.3390/cells7120231 ◽

2018 ◽

Vol 7 (12) ◽

pp. 231 ◽

Cited By ~ 6

Author(s):

Dae Hong ◽

Bo Choi ◽

A Kho ◽

Song Lee ◽

Jeong Jeong ◽

...

Keyword(s):

Cerebral Ischemia ◽

Neuronal Death ◽

Transient Receptor Potential ◽

Therapeutic Potential ◽

Receptor Potential ◽

Global Cerebral Ischemia ◽

Neuroprotective Effects ◽

Transient Receptor Potential Melastatin ◽

Transient Receptor ◽

Zinc Translocation

Over the last two decades, evidence supporting the concept of zinc-induced neuronal death has been introduced, and several intervention strategies have been investigated. Vesicular zinc is released into the synaptic cleft, where it then translocates to the cytoplasm, which leads to the production of reactive oxygen species and neurodegeneration. Carvacrol inhibits transient receptor potential melastatin 7 (TRPM7), which regulates the homeostasis of extracellular metal ions, such as calcium and zinc. In the present study, we test whether carvacrol displays any neuroprotective effects after global cerebral ischemia (GCI), via a blockade of zinc influx. To test our hypothesis, we used eight-week-old male Sprague–Dawley rats, and a GCI model was induced by bilateral common carotid artery occlusion (CCAO), accompanied by blood withdrawal from the femoral artery. Ischemic duration was defined as a seven-minute electroencephalographic (EEG) isoelectric period. Carvacrol (50 mg/kg) was injected into the intraperitoneal space once per day for three days after the onset of GCI. The present study found that administration of carvacrol significantly decreased the number of degenerating neurons, microglial activation, oxidative damage, and zinc translocation after GCI, via downregulation of TRPM7 channels. These findings suggest that carvacrol, a TRPM7 inhibitor, may have therapeutic potential after GCI by reducing intracellular zinc translocation.

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Pore Helix Domain Is Critical to Camphor Sensitivity of Transient Receptor Potential Vanilloid 1 Channel

Anesthesiology ◽

10.1097/aln.0b013e318249cf62 ◽

2012 ◽

Vol 116 (4) ◽

pp. 903-917 ◽

Cited By ~ 9

Author(s):

Lenka Marsakova ◽

Filip Touska ◽

Jan Krusek ◽

Viktorie Vlachova

Keyword(s):

Spatial Distribution ◽

Plasma Membranes ◽

Transient Receptor Potential ◽

Receptor Potential ◽

Structural Basis ◽

Transient Receptor Potential Vanilloid ◽

Trpv1 Channel ◽

Patch Clamp Technique ◽

Trpv1 Channels ◽

Transient Receptor

Background The recent discovery that camphor activates and strongly desensitizes the capsaicin-sensitive and noxious heat-sensitive channel transient receptor potential vanilloid subfamily member 1 (TRPV1) has provided new insights and opened up new research paths toward understanding why this naturally occurring monoterpene is widely used in human medicine for its local counter-irritant, antipruritic, and anesthetic properties. However, the molecular basis for camphor sensitivity remains mostly unknown. The authors attempt to explore the nature of the activation pathways evoked by camphor and narrow down a putative interaction site at TRPV1. Methods The authors transiently expressed wild-type or specifically mutated recombinant TRPV1 channels in human embryonic kidney cells HEK293T and recorded cation currents with the whole cell, patch clamp technique. To monitor changes in the spatial distribution of phosphatidylinositol 4,5-bisphosphate, they used fluorescence resonance energy transfer measurements from cells transfected with the fluorescent protein-tagged pleckstrin homology domains of phospholipase C. Results The results revealed that camphor modulates TRPV1 channel through the outer pore helix domain by affecting its overall gating equilibrium. In addition, camphor, which generally is known to decrease the fluidity of cell plasma membranes, may also regulate the activity of TRPV1 by inducing changes in the spatial distribution of phosphatidylinositol-4,5-bisphosphate on the inner leaflet of the plasma membrane. Conclusions The findings of this study provide novel insights into the structural basis for the modulation of TRPV1 channel by camphor and may provide an explanation for the mechanism by which camphor modulates thermal sensation in vivo.

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Structural basis of cooling agent and lipid sensing by the cold-activated TRPM8 channel

Science ◽

10.1126/science.aav9334 ◽

2019 ◽

Vol 363 (6430) ◽

pp. eaav9334 ◽

Cited By ~ 66

Author(s):

Ying Yin ◽

Son C. Le ◽

Allen L. Hsu ◽

Mario J. Borgnia ◽

Huanghe Yang ◽

...

Keyword(s):

Transient Receptor Potential ◽

Structural Information ◽

Receptor Potential ◽

Membrane Lipid ◽

Structural Basis ◽

Trpm8 Channel ◽

Allosteric Coupling ◽

Transient Receptor Potential Melastatin ◽

Lipid Sensing ◽

Transient Receptor

Transient receptor potential melastatin member 8 (TRPM8) is a calcium ion (Ca2+)–permeable cation channel that serves as the primary cold and menthol sensor in humans. Activation of TRPM8 by cooling compounds relies on allosteric actions of agonist and membrane lipid phosphatidylinositol 4,5-bisphosphate (PIP2), but lack of structural information has thus far precluded a mechanistic understanding of ligand and lipid sensing by TRPM8. Using cryo–electron microscopy, we determined the structures of TRPM8 in complex with the synthetic cooling compound icilin, PIP2, and Ca2+, as well as in complex with the menthol analog WS-12 and PIP2. Our structures reveal the binding sites for cooling agonists and PIP2in TRPM8. Notably, PIP2binds to TRPM8 in two different modes, which illustrate the mechanism of allosteric coupling between PIP2and agonists. This study provides a platform for understanding the molecular mechanism of TRPM8 activation by cooling agents.

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The Transient Receptor Potential Melastatin 7 (TRPM7) Inhibitors Suppress Seizure-Induced Neuron Death by Inhibiting Zinc Neurotoxicity

International Journal of Molecular Sciences ◽

10.3390/ijms21217897 ◽

2020 ◽

Vol 21 (21) ◽

pp. 7897

Author(s):

Jeong Hyun Jeong ◽

Song Hee Lee ◽

A Ra Kho ◽

Dae Ki Hong ◽

Dong Hyeon Kang ◽

...

Keyword(s):

Transient Receptor Potential ◽

Therapeutic Potential ◽

Divalent Cations ◽

Neurological Diseases ◽

Receptor Potential ◽

Neuron Death ◽

Intracellular Zinc ◽

Transient Receptor Potential Melastatin ◽

Transient Receptor ◽

Induced Neuron

Transient receptor potential melastatin 7 (TRPM7) is an ion channel that mediates monovalent cations out of cells, as well as the entry of divalent cations, such as zinc, magnesium, and calcium, into the cell. It has been reported that inhibitors of TRPM7 are neuroprotective in various neurological diseases. Previous studies in our lab suggested that seizure-induced neuronal death may be caused by the excessive release of vesicular zinc and the subsequent accumulation of zinc in the neurons. However, no studies have evaluated the effects of carvacrol and 2-aminoethoxydiphenyl borate (2-APB), both inhibitors of TRPM7, on the accumulation of intracellular zinc in dying neurons following seizure. Here, we investigated the therapeutic efficacy of carvacrol and 2-APB against pilocarpine-induced seizure. Carvacrol (50 mg/kg) was injected once per day for 3 or 7 days after seizure. 2-APB (2 mg/kg) was also injected once per day for 3 days after seizure. We found that inhibitors of TRPM7 reduced seizure-induced TRPM7 overexpression, intracellular zinc accumulation, and reactive oxygen species production. Moreover, there was a suppression of oxidative stress, glial activation, and the blood–brain barrier breakdown. In addition, inhibitors of TRPM7 remarkably decreased apoptotic neuron death following seizure. Taken together, the present study demonstrates that TRPM7-mediated zinc translocation is involved in neuron death after seizure. The present study suggests that inhibitors of TRPM7 may have high therapeutic potential to reduce seizure-induced neuron death.

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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.

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A hypothetical molecular mechanism for TRPV1 activation that invokes rotation of an S6 asparagine

The Journal of General Physiology ◽

10.1085/jgp.201812124 ◽

2018 ◽

Vol 150 (11) ◽

pp. 1554-1566 ◽

Cited By ~ 16

Author(s):

Marina A. Kasimova ◽

Aysenur Torun Yazici ◽

Yevgen Yudin ◽

Daniele Granata ◽

Michael L. Klein ◽

...

Keyword(s):

Molecular Mechanism ◽

Conformational Changes ◽

Transient Receptor Potential ◽

Ionic Conduction ◽

Receptor Potential ◽

Transient Receptor Potential Channel ◽

Activation Mechanism ◽

Bioinformatics Analyses ◽

Water Accessibility ◽

Transient Receptor

The transient receptor potential channel vanilloid type 1 (TRPV1) is activated by a variety of endogenous and exogenous stimuli and is involved in nociception and body temperature regulation. Although the structure of TRPV1 has been experimentally determined in both the closed and open states, very little is known about its activation mechanism. In particular, the conformational changes that occur in the pore domain and result in ionic conduction have not yet been identified. Here we suggest a hypothetical molecular mechanism for TRPV1 activation, which involves rotation of a conserved asparagine in S6 from a position facing the S4–S5 linker toward the pore. This rotation is associated with hydration of the pore and dehydration of the four peripheral cavities located between each S6 and S4–S5 linker. In light of our hypothesis, we perform bioinformatics analyses of TRP and other evolutionary related ion channels, evaluate newly available structures, and reexamine previously reported water accessibility and mutagenesis experiments. These analyses provide several independent lines of evidence to support our hypothesis. Finally, we show that our proposed molecular mechanism is compatible with the prevailing theory that the selectivity filter acts as a secondary gate in TRPV1.

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Structural insights into TRPM8 inhibition and desensitization

Science ◽

10.1126/science.aax6672 ◽

2019 ◽

Vol 365 (6460) ◽

pp. 1434-1440 ◽

Cited By ~ 37

Author(s):

Melinda M. Diver ◽

Yifan Cheng ◽

David Julius

Keyword(s):

Conformational Changes ◽

Calcium Binding ◽

Transient Receptor Potential ◽

Trp Channels ◽

Receptor Potential ◽

Binding Pocket ◽

Chemical Structures ◽

Transient Receptor Potential Melastatin ◽

Transient Receptor ◽

Large Rearrangements

The transient receptor potential melastatin 8 (TRPM8) ion channel is the primary detector of environmental cold and an important target for treating pathological cold hypersensitivity. Here, we present cryo–electron microscopy structures of TRPM8 in ligand-free, antagonist-bound, or calcium-bound forms, revealing how robust conformational changes give rise to two nonconducting states, closed and desensitized. We describe a malleable ligand-binding pocket that accommodates drugs of diverse chemical structures, and we delineate the ion permeation pathway, including the contribution of lipids to pore architecture. Furthermore, we show that direct calcium binding mediates stimulus-evoked desensitization, clarifying this important mechanism of sensory adaptation. We observe large rearrangements within the S4-S5 linker that reposition the S1-S4 and pore domains relative to the TRP helix, leading us to propose a distinct model for modulation of TRPM8 and possibly other TRP channels.

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Upregulation of the TRPA1 Ion Channel in the Gastric Mucosa after Iodoacetamide-Induced Gastritis in Rats: A Potential New Therapeutic Target

International Journal of Molecular Sciences ◽

10.3390/ijms21165591 ◽

2020 ◽

Vol 21 (16) ◽

pp. 5591

Author(s):

Kata Csekő ◽

Dániel Pécsi ◽

Béla Kajtár ◽

Ivett Hegedűs ◽

Alexander Bollenbach ◽

...

Keyword(s):

Transient Receptor Potential ◽

Therapeutic Potential ◽

Receptor Potential ◽

Protective Mechanisms ◽

Inflammatory Infiltration ◽

Trpv1 Channels ◽

Acute Gastritis ◽

Gastric Corpus ◽

Transient Receptor

Acute gastritis is often untreatable by acid secretion-inhibiting drugs. Understanding the protective mechanisms including the role of Transient Receptor Potential Ankyrin1 (TRPA1) and Vanilloid1 (TRPV1) channels localized on capsaicin-sensitive afferents and non-neuronal structures might identify novel therapeutic approaches. Therefore, we characterized a translational gastritis model using iodoacetamide (IAA) and investigated TRPA1/V1 expressions. Wistar rats and CD1, C57Bl/6J mice were exposed to IAA-containing (0.05, 0.1, 0.2, 0.3, 0.5%) drinking water for 7 or 14 days. Body weight and water consumption were recorded daily. Macroscopic lesions were scored, qualitative histopathologic investigation was performed, TRPA1/V1 immunopositivity and mRNA expressions were measured. IAA induced a concentration-dependent weight loss and reduced water intake in both species. Hyperemia, submucosal edema, inflammatory infiltration and hemorrhagic erosions developed after 7 days, while ulcers after 14 days in rats. Trpa1 mRNA/protein expressions were upregulated at both timepoints. Meanwhile, TRPV1 immunopositivity was upregulated in the gastric corpus after 0.05% IAA ingestion, but downregulated after 0.2%, whereas Trpv1 mRNA did not change. Interestingly, no macroscopic/microscopic changes were observed in mice. These are the first data for the concentration- and duration-dependent changes in the IAA-induced gastritis in rats accompanied by TRPA1 upregulation, therefore, its therapeutic potential in gastritis should further be investigated.

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