How the mole-rat lost its pain: Pain alerts our bodies that something is amiss and typically we stop the pain-causing activity. Numerous species of plants and prey animals take advantage of this response by producing pain-causing substances that are released during predation attempts. In turn, species that encounter these substances often evolve ways of turning off the pain-producing mechanism. Eigenbrod et al. searched RNA transcripts in eight species of subterranean rodents related to pain-resistant naked mole-rats. They found multiple changes to ion channels involved in pain across the different species. Understanding such adaptations could elucidate pain mechanisms and help us develop approaches for pain relief. Science , this issue p. 852
Touch perception is enabled by mechanically activated ion channels, the opening of which excites cutaneous sensory endings to initiate sensation. In this study, we identify ELKIN1 as an ion channel likely gated by mechanical force, necessary for normal touch sensitivity in mice. Touch insensitivity in
Elkin1
−/− mice was caused by a loss of mechanically activated currents (MA currents) in around half of all sensory neurons activated by light touch (low-threshold mechanoreceptors). Reintroduction of Elkin1 into sensory neurons from
Elkin1
−/− mice restored MA currents. Additionally, small interfering RNA–mediated knockdown of ELKIN1 from induced human sensory neurons substantially reduced indentation-induced MA currents, supporting a conserved role for ELKIN1 in human touch. Our data identify ELKIN1 as a core component of touch transduction in mice and potentially in humans.
The force-gated ion channel PIEZO1 confers mechanosensitivity to many cell types. While the structure and physiological roles of PIEZO1 are well-described, the subcellular distribution and the impact of the cellular microenvironment on PIEZO1 conformation and function are poorly understood. Here, using MINFLUX nanoscopy, we demonstrate that PIEZO1 channels accumulate in pit-shaped invaginations that are distinct from classical membrane invaginations such as clathrin-coated pits and caveolae, thereby possibly creating hotspots for mechanotransduction. Moreover, by measuring intramolecular distances in individual PIEZO1 channels with nanometer precision, we reveal subcellular compartment-specific differences in PIEZO1 conformation at rest and during activation that correlate with differences in PIEZO1 function and are possibly caused by differences in cytoskeletal architecture. Together, our data provide previously unrecognized insights into the complex interplay of forces that determine how PIEZO1 alters membrane shape and, vice versa, how the membrane together with the cytoskeleton affect the conformation and function of individual PIEZO1 channels.
Coronary arteries develop under constant mechanical stress. However, the role of mechanosensitive ion channels in this process remains poorly understood. Here we show that the ion channel PIEZO2, which responds to mechanical stimuli, is expressed in specific coronary endothelial cell populations during a critical phase of coronary vasculature remodeling. These Piezo2+ coronary endothelial cells show distinct transcriptional profiles and have mechanically activated ionic currents. Strikingly, PIEZO2 loss-of-function mouse embryos and mice with human pathogenic variants of PIEZO2 show abnormal coronary vessel development and cardiac left ventricular hyperplasia. We conclude that an optimal balance of PIEZO2 channel function contributes to proper coronary vessel formation, structural integrity and remodeling, and is likely to support normal cardiac function. Our study highlights the importance of mechanical cues in cardiovascular development and suggests that defects in this mechanosensing pathway may contribute to congenital heart conditions.
The use of Botulinum Neurotoxin A (BoNT/A) to treat peripheral neuropathic pain from nerve injury has garnered interest for its long-lasting effects and safety. This study examined the effects of IncobotulinumtoxinA (Inco/A), a BoNT/A variant without accessory proteins, on nerve regeneration in rats using the chronic constriction injury (CCI) model. Inco/A was administered perineurally at two time points: on days 0 and 21 post CCI. Functional and histological assessments were conducted to evaluate the effect of Inco/A on nerve regeneration. Sciatic Functional Index (SFI) measurements and Compound Muscle Action Potential (CMAP) recordings were conducted at different time points following CCI. Inco/A-treated animals exhibited a 65% improved SFI and 22% reduction in CMAP onset latencies compared to the vehicle-treated group, suggesting accelerated functional nerve recovery. Tissue analysis revealed enhanced remyelination in Inco/A-treated animals and 60% reduction in CGRP and double S100β signal expression compared to controls. Strikingly, 30% reduced immune cell influx into the injury site was observed following Inco/A treatment, suggesting that its anti-inflammatory effect contributes to nerve regeneration. These findings show that two injections of Inco/A promote functional recovery by enhancing neuroregeneration and modulating inflammatory processes, supporting the hypothesis that Inco/A has a neuroprotective and restorative role in nerve injury conditions.
PIEZO2 mechanosensitive channels are required for normal touch sensation. However, PIEZO2 channels are almost completely blocked at negative resting membrane potentials. We show that PIEZO2 voltage-block can be relieved by mutations at a conserved Arginine (R2756) which dramatically sensitizes the channel to mechanical stimuli. We generated Piezo2R2756H/R2756H and Piezo2R2756K/R2756Kknock-in mice to ask how voltage regulates the endogenous mechanosensitivity of sensory neurons. Surprisingly, mechanosensitive currents in nociceptors, neurons that detect noxious mechanical stimuli, were substantially sensitized in Piezo2 knock-in mice, but touch receptors were largely unaffected. Piezo2 knock-in mice were hypersensitive to noxious mechanical stimuli as their nociceptors acquired properties similar to ultrasensitive touch receptors. Thus, mechanical pain sensitivity can be tuned by voltage-block of PIEZO2 channels, a channel property potentially amenable for pharmacological modulation.