scholarly journals TACAN is an essential component of the mechanosensitive ion channel responsible for pain sensing

2018 ◽  
Author(s):  
L. Beaulieu-Laroche ◽  
M. Christin ◽  
AM Donoghue ◽  
F. Agosti ◽  
N. Yousefpour ◽  
...  
Keyword(s):  
Ion Channels ◽  
Heterologous Expression ◽  
Ion Channel ◽  
Behavioral Responses ◽  
Mechanical Stimuli ◽  
Thermal Pain ◽  
Fundamental Process ◽  
Mechanosensitive Ion Channel ◽  
Pain Stimuli ◽  
Essential Subunit

SummaryMechanotransduction, the conversion of mechanical stimuli into electrical signals, is a fundamental process underlying several physiological functions such as touch and pain sensing, hearing and proprioception. This process is carried out by specialized mechanosensitive ion channels whose identities have been discovered for most functions except pain sensing. Here we report the identification of TACAN (Tmem120A), an essential subunit of the mechanosensitive ion channel responsible for sensing mechanical pain. TACAN is expressed in a subset of nociceptors, and its heterologous expression increases mechanically-evoked currents in cell lines. Purification and reconstitution of TACAN in synthetic lipids generates a functional ion channel. Finally, knocking down TACAN decreases the mechanosensitivity of nociceptors and reduces behavioral responses to mechanical but not to thermal pain stimuli, without affecting the sensitivity to touch stimuli. We propose that TACAN is a pore-forming subunit of the mechanosensitive ion channel responsible for sensing mechanical pain.

scholarly journals Fluorescence Microscopy of Piezo1 in Droplet Hydrogel Bilayers

2018 ◽  
Author(s):  
Oskar B. Jaggers ◽  
Pietro Ridone ◽  
Boris Martinac ◽  
Matthew A. B. Baker
Keyword(s):  
Ion Channels ◽  
Ion Channel ◽  
Simultaneous Recording ◽  
Mechanical Stimuli ◽  
Channel Activity ◽  
Channel Proteins ◽  
Mechanosensitive Ion Channel ◽  
Lymphatic Dysplasia ◽  
Hydrogel Bilayer

AbstractMechanosensitive ion channels are membrane gated pores which are activated by mechanical stimuli. The focus of this study is on Piezo1, a newly discovered, large, mammalian, mechanosensitive ion channel, which has been linked to diseases such as dehydrated hereditary stomatocytosis (Xerocytosis) and lymphatic dysplasia. Here we utilize an established in-vitro artificial bilayer system to interrogate single Piezo1 channel activity. The droplet-hydrogel bilayer (DHB) system uniquely allows the simultaneous recording of electrical activity and fluorescence imaging of labelled protein. We successfully reconstituted fluorescently labelled Piezo1 ion channels in DHBs and verified activity using electrophysiology in the same system. We demonstrate successful insertion and activation of hPiezo1-GFP in bilayers of varying composition. Furthermore, we compare the Piezo1 bilayer reconstitution with measurements of insertion and activation of KcsA channels to reproduce the channel conductances reported in the literature. Together, our results showcase the use of DHBs for future experiments allowing simultaneous measurements of ion channel gating while visualising the channel proteins using fluorescence.

scholarly journals Mechanosensitive Ion Channel Piezo1 Regulates Myocyte Fusion during Skeletal Myogenesis

2020 ◽  
Author(s):  
Huascar Pedro Ortuste Quiroga ◽  
Shingo Yokoyama ◽  
Massimo Ganassi ◽  
Kodai Nakamura ◽  
Tomohiro Yamashita ◽  
...  
Keyword(s):  
Ion Channel ◽  
Molecular Mechanisms ◽  
Myoblast Fusion ◽  
Mechanical Stimuli ◽  
Muscle Satellite Cell ◽  
Myotube Formation ◽  
Mechanosensitive Ion Channel ◽  
And Function ◽  
Sirna Knockdown

AbstractMechanical stimuli such as stretch and resistance training are essential to regulate growth and function of skeletal muscle. However, the molecular mechanisms involved in sensing mechanical stress remain unclear. Here, the purpose of this study was to investigate the role of the mechanosensitive ion channel Piezo1 during myogenic progression. Muscle satellite cell-derived myoblasts and myotubes were modified with stretch, siRNA knockdown and agonist-induced activation of Piezo1. Direct manipulation of Piezo1 modulates terminal myogenic progression. Piezo1 knockdown suppressed myoblast fusion during myotube formation and maturation. This was accompanied by downregulation of the fusogenic protein Myomaker. Piezo1 knockdown also lowered Ca2+ influx in response to stretch. Conversely Piezo1 activation stimulated fusion and increased Ca2+ influx in response to stretch. These evidences indicate that Piezo1 is essential for myotube formation and maturation, which may have implications for msucular dystrophy prevention through its role as a mechanosensitive Ca2+ channel.

scholarly journals Acetylated tubulin is essential for touch sensation in mice

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Shane J Morley ◽  
Yanmei Qi ◽  
Loredana Iovino ◽  
Laura Andolfi ◽  
Da Guo ◽  
...  
Keyword(s):  
Ion Channel ◽  
Sensory Neurons ◽  
Mechanical Energy ◽  
Mechanical Stimuli ◽  
Acetylated Tubulin ◽  
Fundamental Level ◽  
Tubulin Acetylation ◽  
Channel Opening ◽  
Mechanosensitive Ion Channel ◽  
Touch Sensation

At its most fundamental level, touch sensation requires the translation of mechanical energy into mechanosensitive ion channel opening, thereby generating electro-chemical signals. Our understanding of this process, especially how the cytoskeleton influences it, remains unknown. Here we demonstrate that mice lacking the α-tubulin acetyltransferase Atat1 in sensory neurons display profound deficits in their ability to detect mechanical stimuli. We show that all cutaneous afferent subtypes, including nociceptors have strongly reduced mechanosensitivity upon Atat1 deletion, and that consequently, mice are largely insensitive to mechanical touch and pain. We establish that this broad loss of mechanosensitivity is dependent upon the acetyltransferase activity of Atat1, which when absent leads to a decrease in cellular elasticity. By mimicking α-tubulin acetylation genetically, we show both cellular rigidity and mechanosensitivity can be restored in Atat1 deficient sensory neurons. Hence, our results indicate that by influencing cellular stiffness, α-tubulin acetylation sets the force required for touch.

scholarly journals Piezo1 Mediates Keratinocyte Mechanotransduction

2020 ◽  
Author(s):  
Francie Moehring ◽  
Alexander R. Mikesell ◽  
Katelyn E. Sadler ◽  
Anthony D. Menzel ◽  
Cheryl L. Stucky
Keyword(s):  
Ion Channel ◽  
Sensory Neurons ◽  
Mechanical Stimulation ◽  
Behavioral Responses ◽  
Epidermal Keratinocytes ◽  
Mechanical Stimuli ◽  
Tactile Information ◽  
Touch Sensation

AbstractEpidermal keratinocytes mediate touch sensation by detecting and encoding tactile information to sensory neurons. However, the specific mechanotransducers that enable keratinocytes to respond to mechanical stimulation are unknown. Here, we found that the mechanically-gated ion channel Piezo1 is the major keratinocyte mechanotransducer. Keratinocyte expression of Piezo1 is critical for normal sensory afferent firing and behavioral responses to mechanical stimuli.

scholarly journals The Tarantula Toxin Psalmotoxin 1 Inhibits Acid-sensing Ion Channel (ASIC) 1a by Increasing Its Apparent H+ Affinity

2005 ◽  
Vol 126 (1) ◽  
pp. 71-79 ◽  
Author(s):  
Xuanmao Chen ◽  
Hubert Kalbacher ◽  
Stefan Gründer
Keyword(s):  
Ion Channels ◽  
Ion Channel ◽  
Therapeutic Intervention ◽  
Mechanical Stimuli ◽  
Apparent Affinity ◽  
Brain Functions ◽  
Acid Sensing Ion Channels ◽  
Higher Brain Functions ◽  
Unique Mechanism

Acid-sensing ion channels (ASICs) are ion channels activated by extracellular protons. They are involved in higher brain functions and perception of pain, taste, and mechanical stimuli. Homomeric ASIC1a is potently inhibited by the tarantula toxin psalmotoxin 1. The mechanism of this inhibition is unknown. Here we show that psalmotoxin 1 inhibits ASIC1a by a unique mechanism: the toxin increases the apparent affinity for H+ of ASIC1a. Since ASIC1a is activated by H+ concentrations that are only slightly larger than the resting H+ concentration, this increase in H+ affinity is sufficient to shift ASIC1a channels into the desensitized state. As activation of ASIC1a has recently been linked to neurodegeneration associated with stroke, our results suggest chronic desensitization of ASIC1a by a slight increase of its H+ affinity as a possible way of therapeutic intervention in stroke.

scholarly journals Machine-Learned Association of Next-Generation Sequencing-Derived Variants in Thermosensitive Ion Channels Genes with Human Thermal Pain Sensitivity Phenotypes

2020 ◽  
Vol 21 (12) ◽  
pp. 4367 ◽  
Author(s):  
Jörn Lötsch ◽  
Dario Kringel ◽  
Gerd Geisslinger ◽  
Bruno G. Oertel ◽  
Eduard Resch ◽  
...  
Keyword(s):  
Machine Learning ◽  
Next Generation Sequencing ◽  
Ion Channels ◽  
Ion Channel ◽  
Genetic Variants ◽  
Genetic Information ◽  
Pain Thresholds ◽  
Thermal Pain ◽  
Thermal Stimuli ◽  
Generation Sequencing

Genetic association studies have shown their usefulness in assessing the role of ion channels in human thermal pain perception. We used machine learning to construct a complex phenotype from pain thresholds to thermal stimuli and associate it with the genetic information derived from the next-generation sequencing (NGS) of 15 ion channel genes which are involved in thermal perception, including ASIC1, ASIC2, ASIC3, ASIC4, TRPA1, TRPC1, TRPM2, TRPM3, TRPM4, TRPM5, TRPM8, TRPV1, TRPV2, TRPV3, and TRPV4. Phenotypic information was complete in 82 subjects and NGS genotypes were available in 67 subjects. A network of artificial neurons, implemented as emergent self-organizing maps, discovered two clusters characterized by high or low pain thresholds for heat and cold pain. A total of 1071 variants were discovered in the 15 ion channel genes. After feature selection, 80 genetic variants were retained for an association analysis based on machine learning. The measured performance of machine learning-mediated phenotype assignment based on this genetic information resulted in an area under the receiver operating characteristic curve of 77.2%, justifying a phenotype classification based on the genetic information. A further item categorization finally resulted in 38 genetic variants that contributed most to the phenotype assignment. Most of them (10) belonged to the TRPV3 gene, followed by TRPM3 (6). Therefore, the analysis successfully identified the particular importance of TRPV3 and TRPM3 for an average pain phenotype defined by the sensitivity to moderate thermal stimuli.

scholarly journals GenEPi: Piezo1-based fluorescent reporter for visualizing mechanical stimuli with high spatiotemporal resolution

2019 ◽  
Author(s):  
Sine Yaganoglu ◽  
Nordine Helassa ◽  
Benjamin M. Gaub ◽  
Maaike Welling ◽  
Jian Shi ◽  
...  
Keyword(s):  
Ion Channel ◽  
High Specificity ◽  
Mechanical Stimuli ◽  
Spatiotemporal Resolution ◽  
Fluorescent Reporter ◽  
Non Invasive ◽  
Live Tissue ◽  
Biological Responses ◽  
Mechanosensitive Ion Channel ◽  
Cellular Mechanosensing

AbstractMechanosensing is a ubiquitous process to translate external mechanical stimuli into biological responses during development, homeostasis, and disease. However, non-invasive investigation of cellular mechanosensing in complex and intact live tissue remains challenging. Here, we developed GenEPi, a genetically-encoded fluorescent intensiometric reporter for mechanical stimuli based on Piezo1, an essential mechanosensitive ion channel found in vertebrates. We show that GenEPi has high specificity and spatiotemporal resolution for Piezo1-dependent mechanical stimuli, exemplified by resolving repetitive mechanical stimuli of spontaneously contracting cardiomyocytes within microtissues, in a non-invasive manner.

scholarly journals Ultrasound elicits behavioral responses through mechanical effects on neurons and ion channels in a simple nervous system

2017 ◽  
Author(s):  
Jan Kubanek ◽  
Poojan Shukla ◽  
Alakananda Das ◽  
Stephen A. Baccus ◽  
Miriam B. Goodman
Keyword(s):  
Nervous System ◽  
Ion Channels ◽  
Ion Channel ◽  
Behavioral Responses ◽  
Thermal Fluctuations ◽  
Dependent Manner ◽  
Wild Type ◽  
Excitable Cells ◽  
C Elegans ◽  
Mechanical Effects

AbstractFocused ultrasound has been shown to stimulate excitable cells, but the biophysical mechanisms behind this phenomenon remain poorly understood. To provide additional insight, we devised a behavioral-genetic assay applied to the well-characterized nervous system of C. elegans nematodes. We found that pulsed ultrasound elicits robust reversal behavior in wild-type animals in a pressure-, duration-, and pulse protocol-dependent manner. Responses were preserved in mutants unable to sense thermal fluctuations and absent in mutants lacking neurons required for mechanosensation. Additionally, we found that the worm‘s response to ultrasound pulses rests on the expression of MEC-4, a DEG/ENaC/ASIC ion channel required for touch sensation. Consistent with prior studies of MEC-4-dependent currents in vivo, the worm’s response was optimal for pulses repeated 300 to 1000 times per second. Based on these findings, we conclude that mechanical, rather than thermal stimulation accounts for behavioral responses. Further, we propose that acoustic radiation force governs the response to ultrasound in a manner that depends on the touch receptor neurons and MEC-4-dependent ion channels. Our findings illuminate a complete pathway of ultrasound action, from the forces generated by propagating ultrasound to an activation of a specific ion channel. The findings further highlight the importance of optimizing ultrasound pulsing protocols when stimulating neurons via ion channels with mechanosensitive properties.Significance StatementHow ultrasound influences neurons and other excitable cells has remained a mystery for decades. Although it is widely understood that ultrasound can heat tissues and induce mechanical strain, whether or not neuronal activation depends on heat, mechanical force, or both physical factors is not known. We harnessed C. elegans nematodes and their extraordinary sensitivity to thermal and mechanical stimuli to address this question. Whereas thermosensory mutants respond to ultrasound similar to wild-type animals, mechanosensory mutants were insensitive to ultrasound stimulation. Additionally, stimulus parameters that accentuate mechanical effects were more effective than those producing more heat. These findings highlight a mechanical nature of the effect of ultrasound on neurons and suggest specific ways to optimize stimulation protocols in specific tissues.

scholarly journals Push-to-open: The Gating Mechanism of the Tethered Mechanosensitive Ion Channel NompC

2019 ◽  
Author(s):  
Yang Wang ◽  
Yifeng Guo ◽  
Chunhong Liu ◽  
Lei Wang ◽  
Aihua Zhang ◽  
...  
Keyword(s):  
Ion Channels ◽  
Ion Channel ◽  
Mechanical Force ◽  
Loss Of Function ◽  
Mechanosensitive Ion Channels ◽  
Gating Model ◽  
Gating Mechanism ◽  
Mechanosensitive Ion Channel ◽  
Significant Conformational Change ◽  
Dynamics Simulations

AbstractNompC was one of the earliest identified mechanosensitive ion channels responsible for the sensation of touch and balance in Drosophila melanogaster. A tethered gating model was proposed for NompC and the Cryo-EM structure has been solved. However, the atomistic mechano-gating mechanism still remains elusive. Here we show the atomistic details of the NompC channel opening in response to the compression of the intracellular domain while remaining closed under an intracellular stretch. This is demonstrated by all-atom molecular dynamics simulations and evidenced by electrophysiological experiments. Under intracellular compression, the ankyrin repeat region undergoes a significant conformational change and passes the mechanical force to the linker helices like a spring with a force constant of ~3.3 pN/nm. The linker helix region acts as a bridge between the ankyrin repeats and TRP domain, and most of the mutations breaking the hydrogen bonds around this region lead to the loss-of-function of the channel. Eventually, the compression-induced mechanical force is passed from the linker helices onto the TRP domain, which then undergoes a clockwise rotation that leads to the opening of the channel. This work provides a clear picture of how a pushing force opens the mechanosensitive ion channel NompC, which might be a universal gating mechanism of similar tethered mechanosensitive ion channels, enabling cells to feel and respond to compression or shrinking.

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