Coatable strain sensors for nonplanar surfaces.

Rapidly fabricating flexible and stretchable sensors on nonplanar surfaces is crucial for wearable device applications. We employed a novel fabrication method, incorporating molds and gels into electroless plating, to enable direct printing of sensors on a wide array of surfaces, from those with up to 100 µm profile heights to hydrogels with a Young's modulus of 100 kPa. This coatable strain (CS) sensor offers several potential advantages. Firstly, it is designed to circumvent the typical limitations of limited flexibility, plastic deformation, and low repeatability found in viscoelastic polymers by being directly coated onto the surface without requiring a substrate. Secondly, it potentially increases the effective contact area and signal-to-noise ratio by eliminating voids between the sensor and the surface. Finally, the CS sensor can obtain any desired patterning at room temperature in a matter of minutes, significantly reducing energy and time consumption. In this study, we demonstrated the versatility of the CS sensor by applying it to a range of substrates, showcasing its adaptability to diverse materials, surface roughness levels, and Young's modulus values. Our primary focus was on plant growth monitoring, a challenging application that showcased the sensor's efficacy on surfaces like needles, hairy leaves, and fruits. These applications, traditionally difficult for conventional polymer-based sensors, serve to illustrate the CS sensor's potential in a range of complex environmental contexts. The successful deployment of the CS sensor in these settings suggests its broader applicability in various scientific and technological fields, potentially contributing to significant developments in the area of wearable devices and beyond.

Flexible Sensory Systems: Structural Approaches.

Biology is characterized by smooth, elastic, and nonplanar surfaces; as a consequence, soft electronics that enable interfacing with nonplanar surfaces allow applications that could not be achieved with the rigid and integrated circuits that exist today. Here, we review the latest examples of technologies and methods that can replace elasticity through a structural approach; these approaches can modify mechanical properties, thereby improving performance, while maintaining the existing material integrity. Furthermore, an overview of the recent progress in wave/wrinkle, stretchable interconnect, origami/kirigami, crack, nano/micro, and textile structures is provided. Finally, potential applications and expected developments in soft electronics are discussed.

Anoctamin 1/TMEM16A in pruritoceptors is essential for Mas-related G protein receptor-dependent itch.

ABSTRACT: Itch is an unpleasant sensation that evokes a desire to scratch. Pathologic conditions such as allergy or atopic dermatitis produce severe itching sensation. Mas-related G protein receptors (Mrgprs) are receptors for many endogenous pruritogens. However, signaling pathways downstream to these receptors in dorsal root ganglion (DRG) neurons are not yet understood. We found that anoctamin 1 (ANO1), a Ca 2+ -activated chloride channel, is a transduction channel mediating Mrgpr-dependent itch signals. Genetic ablation of Ano1 in DRG neurons displayed a significant reduction in scratching behaviors in response to acute and chronic Mrgpr-dependent itch models and the epidermal hyperplasia induced by dry skin. In vivo Ca 2+ imaging and electrophysiological recording revealed that chloroquine and other agonists of Mrgprs excited DRG neurons via ANO1. More importantly, the overexpression of Ano1 in DRG neurons of Ano1 -deficient mice rescued the impaired itching observed in Ano1 -deficient mice. These results demonstrate that ANO1 mediates the Mrgpr-dependent itch signaling in pruriceptors and provides clues to treating pathologic itch syndromes.

Focused Patterning of Electrospun Nanofibers Using a Dielectric Guide Structure.

The patterning of electrospun fibers is a key technology applicable to various fields. This study reports a novel focused patterning method for electrospun nanofibers that uses a cylindrical dielectric guide. The finite elements method (FEM) was used to analyze the electric field focusing phenomenon and ground its explanation in established theory. The horizontal and vertical electric field strengths in the simulation are shown to be key factors in determining the spatial distribution of nanofibers. The experimental results demonstrate a relationship between the size of the cylindrical dielectric guide and that of the electrospun area accumulated in the collector. By concentrating the electric field, we were able to fabricate a pattern of less than 6 mm. The demonstration of continuous line and square patterning shows that the electrospun area can be well controlled. This novel patterning method can be used in a variety of applications, such as sensors, biomedical devices, batteries, and composites.

Preparation of multilayer periodic nanopatterned WO3-based photoanode by reverse nanoimprinting for water splitting.

Photoelectrochemical (PEC) water splitting has been studied extensively as an environmentally friendly technology for hydrogen production using solar energy. WO3is considered a promising semiconducting material for photoanodes due to its high electron mobility, good hole diffusion length, and chemical stability. Periodic nanostructures of WO3have been investigated for enhancing the PEC performance of WO3-based photoanodes. In this study, facile fabrication of periodic nanostructures of WO3was achieved using reverse nanoimprint lithography, and the multilayer stacking of nanopatterned WO3film was also confirmed. The multilayer nanopatterned WO3films were used as photoanodes for PEC water splitting. The performance of the fabricated photoanode in PEC was 2 times higher than that of planar WO3film due to its higher light absorbance and lower charge transfer resistance.

TMEM16A expression in cholinergic neurons of the medial habenula mediates anxiety-related behaviors.

TMEM16A, a Ca2+ -activated Cl- channel, is known to modulate the excitability of various types of cells; however, its function in central neurons is largely unknown. Here, we show the specific expression of TMEM16A in the medial habenula (mHb) via RNAscope in situ hybridization, immunohistochemistry, and electrophysiology. When TMEM16A is ablated in the mHb cholinergic neurons (TMEM16A cKO mice), the slope of after-hyperpolarization of spontaneous action potentials decreases and the firing frequency is reduced. Reduced mHb activity also decreases the activity of the interpeduncular nucleus (IPN). Moreover, TMEM16A cKO mice display anxiogenic behaviors and deficits in social interaction without despair-like phenotypes or cognitive dysfunctions. Finally, chemogenetic inhibition of mHb cholinergic neurons using the DREADD (Designer Receptors Exclusively Activated by Designer Drugs) approach reveals similar behavioral phenotypes to those of TMEM16A cKO mice. We conclude that TMEM16A plays a key role in anxiety-related behaviors regulated by mHb cholinergic neurons and could be a potential therapeutic target against anxiety-related disorders.

Anoctamin 1/TMEM16A controls intestinal Cl- secretion induced by carbachol and cholera toxin.

Calcium-activated chloride channels (CaCCs) mediate numerous physiological functions and are best known for the transport of electrolytes and water in epithelia. In the intestine, CaCC currents are considered necessary for the secretion of fluid to protect the intestinal epithelium. Although genetic ablation of ANO1/TMEM16A, a gene encoding a CaCC, reduces the carbachol-induced secretion of intestinal fluid, its mechanism of action is still unknown. Here, we confirm that ANO1 is essential for the secretion of intestinal fluid. Carbachol-induced transepithelial currents were reduced in the proximal colon of Ano1-deficient mice. Surprisingly, cholera toxin-induced and cAMP-induced fluid secretion, believed to be mediated by CFTR, were also significantly reduced in the intestine of Ano1-deficient mice. ANO1 is largely expressed in the apical membranes of intestines, as predicted for CaCCs. The Ano1-deficient colons became edematous under basal conditions and had a greater susceptibility to dextran sodium sulfate-induced colitis. However, Ano1 depletion failed to affect tumor development in a model of colorectal cancer. We thus conclude that ANO1 is necessary for cAMP- and carbachol-induced Cl- secretion in the intestine, which is essential for the protection of the intestinal epithelium from colitis.

ANO1/TMEM16A regulates process maturation in radial glial cells in the developing brain.

Neural stem cells (NSCs) are primary progenitor cells in the early developmental stage in the brain that initiate a diverse lineage of differentiated neurons and glia. Radial glial cells (RGCs), a type of neural stem cell in the ventricular zone, are essential for nurturing and delivering new immature neurons to the appropriate cortical target layers. Here we report that Anoctamin 1 (ANO1)/TMEM16A, a Ca2+-activated chloride channel, mediates the Ca2+-dependent process extension of RGCs. ANO1 is highly expressed and functionally active in RGCs of the mouse embryonic ventricular zone. Knockdown of ANO1 suppresses RGC process extension and protrusions, whereas ANO1 overexpression stimulates process extension. Among various trophic factors, brain-derived neurotrophic factor (BDNF) activates ANO1, which is required for BDNF-induced process extension in RGCs. More importantly, Ano1-deficient mice exhibited disrupted cortical layers and reduced cortical thickness. We thus conclude that the regulation of RGC process extension by ANO1 contributes to the normal formation of mouse embryonic brain.

Trpm2 Ablation Accelerates Protein Aggregation by Impaired ADPR and Autophagic Clearance in the Brain.

TRPM2 a cation channel is also known to work as an enzyme that hydrolyzes highly reactive, neurotoxic ADP-ribose (ADPR). Although ADPR is hydrolyzed by NUT9 pyrophosphatase in major organs, the enzyme is defective in the brain. The present study questions the role of TRPM2 in the catabolism of ADPR in the brain. Genetic ablation of Trpm2 results in the disruption of ADPR catabolism that leads to the accumulation of ADPR and reduction in AMP. Trpm2-/- mice elicit the reduction in autophagosome formation in the hippocampus. Trpm2-/- mice also show aggregations of proteins in the hippocampus, aberrant structural changes and neuronal connections in synapses, and neuronal degeneration. Trpm2-/- mice exhibit learning and memory impairment, enhanced neuronal intrinsic excitability, and imbalanced synaptic transmission. These results respond to long-unanswered questions regarding the potential role of the enzymatic function of TRPM2 in the brain, whose dysfunction evokes protein aggregation. In addition, the present finding answers to the conflicting reports such as neuroprotective or neurodegenerative phenotypes observed in Trpm2-/- mice.

Anoctamin 9/TMEM16J is a cation channel activated by cAMP/PKA signal.

Anoctamins (ANOs) are multifunctional membrane proteins that consist of 10 homologs. ANO1 (TMEM16A) and ANO2 (TMEM16B) are anion channels activated by intracellular calcium that meditate numerous physiological functions. ANO6 is a scramblase that redistributes phospholipids across the cell membrane. The other homologs are not well characterized. We found ANO9/TMEM16J is a cation channel activated by a cAMP-dependent protein kinase A (PKA). Intracellular cAMP-activated robust currents in whole cells expressing ANO9, which were inhibited by a PKA blocker. A cholera toxin that persistently stimulated adenylate cyclase activated ANO9 as did the application of PKA. The cAMP-induced ANO9 currents were permeable to cations. The cAMP-dependent ANO9 currents were augmented by intracellular Ca2+. Ano9 transcripts were predominant in the intestines. Human intestinal SW480 cells expressed high levels of Ano9 transcripts and showed PKA inhibitor-reversible cAMP-dependent currents. We conclude that ANO9 is a cation channel activated by a cAMP/PKA pathway and could play a role in intestine function.

Involuntary swimming exercise in pregnant rats disturbs ERK1/2 signaling in embryonic neurons through increased cortisol in the amniotic fluid.

Harmful maternal behaviors, such as drinking and smoking, negatively affect embryonic development. In contrast, regular maternal exercise is believed to be beneficial to the fetus. Although it is not surprising that voluntary physical activities are advantageous to fetal development, it remains unclear whether involuntary maternal exercise has similar effects. The constituents of the amniotic fluid (AF) inevitably reflect the maternal plasma. Therefore, it is speculated that exercise-induced changes in maternal plasma can influence fetal development through changes in AF composition. Therefore, we investigated the effect of AF on fetal neurodevelopment and changes in AF composition after involuntary swimming exercise (SE) in an animal model. We found that there was a severe reduction in the number of embryos implanted in the uterus of SE rats. Surprisingly, cortisol level (an inducible stress hormone) was significantly increased in AF from SE rats. In contrast, the growth factors NGF and VEGF were reduced in the AF from SE rats. In the cultured embryonic cortical neurons, the treatment of control (CTL) rat-derived AF significantly increased the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2)-mediated signaling that is essential for fetal neurodevelopment. However, the AF extracted from SE rats reversely suppressed the phosphorylation of ERK1/2-mediated signaling in cortical neurons compared to that in CTL rats. Indeed, the co-treatment with control AF and dexamethasone, a synthetic glucocorticoid, inhibited the phosphorylation of ERK1/2 in a dose-dependent manner. This finding suggests that the inhibition of ERK1/2 can be attributed to increased cortisol level in AF resulting from involuntary exercise. Therefore, involuntary maternal swimming increases cortisol level in AF, which ultimately hinders the ERK1/2 signaling pathway in embryonic neurons. These findings also suggest that involuntary maternal exercise can have undesirable effects on fetal neurodevelopment, which is potentially mediated by elevated AF cortisol level.

Evidence for Mechanosensitive Channel Activity of Tentonin 3/TMEM150C.

Mechanosensation is essential for various physiological processes, and it is mediated by mechanotransduction channels. Recently, we reported that TMEM150C/Tentonin 3 (TTN3) confers mechanically activated currents with slow inactivation kinetics in several cell types, including dorsal root ganglion neurons (Hong et al., 2016). The accompanying Matters Arising by Dubin, Murthy, and colleagues confirms that naive heterologous cells demonstrate a mechanically activated current, but finds that this response is absent in CRISPR-Cas9 Piezo1 knockout cell lines and suggests that TTN3 is a modulator of Piezo1. We present and discuss evidence based on co-expression of TTN3 and Peizo1 and mutant variants of the pore region of TTN3 to support that TTN3 is a pore-forming unit, not an amplifying adaptor for Piezo1 activity. This Matters Arising Response paper, along with Zhao et al. (2017), addresses the Matters Arising from Dubin et al. (2017), published concurrently in this issue of Neuron.

Tentonin 3/TMEM150c Confers Distinct Mechanosensitive Currents in Dorsal-Root Ganglion Neurons with Proprioceptive Function.

Touch sensation or proprioception requires the transduction of mechanical stimuli into electrical signals by mechanoreceptors in the periphery. These mechanoreceptors are equipped with various transducer channels. Although Piezo1 and 2 are mechanically activated (MA) channels with rapid inactivation, MA molecules with other inactivation kinetics have not been identified. Here we report that heterologously expressed Tentonin3 (TTN3)/TMEM150C is activated by mechanical stimuli with distinctly slow inactivation kinetics. Genetic ablation of Ttn3/Tmem150c markedly reduced slowly adapting neurons in dorsal-root ganglion neurons. The MA TTN3 currents were inhibited by known blockers of mechanosensitive ion channels. Moreover, TTN3 was localized in muscle spindle afferents. Ttn3-deficient mice exhibited the loss of coordinated movements and abnormal gait. Thus, TTN3 appears to be a component of a mechanosensitive channel with a slow inactivation rate and contributes to motor coordination. Identification of this gene advances our understanding of the various types of mechanosensations, including proprioception.

TRPM2, a Susceptibility Gene for Bipolar Disorder, Regulates Glycogen Synthase Kinase-3 Activity in the Brain.

Bipolar disorder (BD) is a psychiatric disease that causes mood swings between manic and depressed states. Although genetic linkage studies have shown an association between BD and TRPM2, a Ca(2+)-permeable cation channel, the nature of this association is unknown. Here, we show that D543E, a mutation of Trpm2 that is frequently found in BD patients, induces loss of function. Trpm2-deficient mice exhibited BD-related behavior such as increased anxiety and decreased social responses, along with disrupted EEG functional connectivity. Moreover, the administration of amphetamine in wild-type mice evoked a notable increase in open-field activity that was reversed by the administration of lithium. However, the anti-manic action of lithium was not observed in the Trpm2(-/-) mice. The brains of Trpm2(-/-) mice showed a marked increase in phosphorylated glycogen synthase kinase-3 (GSK-3), a key element in BD-like behavior and a target of lithium. In contrast, activation of TRPM2 induced the dephosphorylation of GSK-3 via calcineurin, a Ca(2+)-dependent phosphatase. Importantly, the overexpression of the D543E mutant failed to induce the dephosphorylation of GSK-3. Therefore, we conclude that the genetic dysfunction of Trpm2 causes uncontrolled phosphorylation of GSK-3, which may lead to the pathology of BD. Our findings explain the long-sought etiologic mechanism underlying the genetic link between Trpm2 mutation and BD. SIGNIFICANCE STATEMENT: Bipolar disorder (BD) is a mental disorder that causes changes in mood and the etiology is still unknown. TRPM2 is highly associated with BD; however, its involvement in the etiology of BD is still unknown. We show here that TRPM2 plays a central role in causing the pathology of BD. We found that D543E, a mutation of Trpm2 frequently found in BD patients, induces the loss of function. Trpm2-deficient mice exhibited mood disturbances and impairments in social cognition. TRPM2 actively regulates the phosphorylation of GSK-3, which is a main target of lithium, a primary medicine for treating BD. Therefore, abnormal regulation of GSK-3 by hypoactive TRPM2 mutants accounts for the pathology of BD, providing the possible link between BD and TRPM2.

Anoctamin 1 (TMEM16A) is essential for testosterone-induced prostate hyperplasia.

Benign prostatic hyperplasia (BPH) is characterized by an enlargement of the prostate, causing lower urinary tract symptoms in elderly men worldwide. However, the molecular mechanism underlying the pathogenesis of BPH is unclear. Anoctamin1 (ANO1) encodes a Ca(2+)-activated chloride channel (CaCC) that mediates various physiological functions. Here, we demonstrate that it is essential for testosterone-induced BPH. ANO1 was highly amplified in dihydrotestosterone (DHT)-treated prostate epithelial cells, whereas the selective knockdown of ANO1 inhibited DHT-induced cell proliferation. Three androgen-response elements were found in the ANO1 promoter region, which is relevant for the DHT-dependent induction of ANO1. Administration of the ANO1 blocker or Ano1 small interfering RNA, inhibited prostate enlargement and reduced histological abnormalities in vivo. We therefore concluded that ANO1 is essential for the development of prostate hyperplasia and is a potential target for the treatment of BPH.

Anoctamin 1 contributes to inflammatory and nerve-injury induced hypersensitivity.

BACKGROUND: Various pathological conditions such as inflammation or injury can evoke pain hypersensitivity. That represents the response to innocuous stimuli or exaggerated response to noxious stimuli. The molecular mechanism based on the pain hypersensitivity is associated with changes in many of ion channels in dorsal-root ganglion (DRG) neurons. Anoctamin 1 (ANO1/TMEM16A), a Ca2+ activated chloride channel is highly visible in small DRG neurons and responds to heat. Mice with an abolished function of ANO1 in DRG neurons demonstrated attenuated pain-like behaviors when exposed to noxious heat, suggesting a role in acute thermal nociception. In this study, we further examined the function of ANO1 in mediating inflammation- or injury-induced hyperalgesia or allodynia. RESULTS: Using Advillin/Ano1fl/fl (Adv/Ano1fl/fl) mice that have a functional ablation of Ano1 mainly in DRG neurons, we were able to determine its role in mediating thermal hyperalgesia and mechanical allodynia induced by inflammation or nerve injury. The thermal hyperalgesia and mechanical allodynia induced by carrageenan injection and spared-nerve injury were significantly reduced in Adv/Ano1fl/fl mice. In addition, flinching or licking behavior after bradykinin or formalin injection was also significantly reduced in Adv/Ano1fl/fl mice. Since pathological conditions augment nociceptive behaviors, we expected ANO1's contribution to the excitability of DRG neurons. Indeed, the application of inflammatory mediators reduced the threshold for action potential (rheobase) or time for induction of the first action potential in DRG neurons isolated from control (Ano1fl/fl) mice. These parameters for neuronal excitability induced by inflammatory mediators were not changed in Adv/Ano1fl/fl mice, suggesting an active contribution of ANO1 in augmenting the neuronal excitability. CONCLUSIONS: In addition to ANO1's role in mediating acute thermal pain as a heat sensor, ANO1 is also capable of augmenting the excitability of DRG neurons under inflammatory or neuropathic conditions and thereby aggravates inflammation- or tissue injury-induced pathological pain.

Voluntary movements as a possible non-reflexive pain assay.

BACKGROUND: The quantification of pain intensity in vivo is essential for identifying the mechanisms of various types of pain or for evaluating the effects of different analgesics. A variety of behavioral tests for pain measurement have been devised, but many are limited because animals are physically restricted, which affects pain sensation. In this study, pain assessment was attempted with minimal physical restriction, and voluntary movements of unrestrained animals were used to evaluate the intensities of various types of pain. RESULTS: The number of times animals reared or total distances traveled was measured using a motion-tracking device and found to be markedly reduced in carrageenan-induced inflammatory, acetic acid-induced visceral, and streptozotocin-induced neuropathic pain tests. These two voluntary movement parameters were found to be highly correlated with paw withdrawal latency from irradiating heat. In addition, these parameters were markedly reversed by morphine and by non-steroidal anti-inflammatory drugs in inflammatory pain models. These parameters were also useful to detect hypoalgesia in TRPV1⁻/⁻ mice. CONCLUSIONS: These results suggest that parameters of voluntary movement, such as, number of rearing and total distance moved, are effective indicators of pain intensity for many types of pain and that they can be used to evaluate degree of pain perception.

An aqueous extract of Poncirus fructus activates the prokinetic activity of 5-HT receptor subtype 4 without hERG interaction.

AIM OF THE STUDY: Poncirus fructus (PF)--also known as the dried, immature fruit of Poncirus trifoliata (L.) Raf. (Rutaceae)--is a natural substance that has long been used for various gastrointestinal disorders in eastern Asia. An aqueous extract of PF (PF-W) has particularly potent gastroprokinetic effects, but its molecular mechanism was not well understood. Identification of the underlying prokinetic mechanism of PF-W was pursued in the present study. MATERIALS AND METHODS: Changes in in vitro cAMP levels and in vivo intestinal transit rate (ITR) caused by PF-W were measured after pretreatment with GR125487, an antagonist for serotonin receptor subtype 4 (5-HT4R). An [(3)H] astemizole binding assay and electrophysiology experiments were performed to determine if PF-W has any interaction with the human ether-à-go-go related gene (hERG) potassium channel. RESULTS: PF-W induced an increase in intracellular cAMP in 5-HT4R-expressing HEK293T cells, indicating that PF-W does activate 5-HT4R. Moreover, pretreatment with GR125487 successfully blocked the increase, suggesting that the response was 5-HT4R-specific. More importantly, pretreatment of GR125487 in rats inhibited the elevation of ITR by PF-W, indicating that the prokinetic effect of PF-W was indeed exerted via 5-HT4R. On the other hand, both [(3)H]-astemizole binding assay and electrophysiological experiments revealed that PF-W did not interfere at all with the hERG channel. CONCLUSION: It was found that PF-W exerts its prokinetic activity through a 5-HT4R-mediated pathway, with no interaction with hERG channels. Therefore, PF-W is a good candidate that might be developed as a prokinetic agent with fewer expected cardiac side effects.

TMEM16A confers receptor-activated calcium-dependent chloride conductance.

Calcium (Ca(2+))-activated chloride channels are fundamental mediators in numerous physiological processes including transepithelial secretion, cardiac and neuronal excitation, sensory transduction, smooth muscle contraction and fertilization. Despite their physiological importance, their molecular identity has remained largely unknown. Here we show that transmembrane protein 16A (TMEM16A, which we also call anoctamin 1 (ANO1)) is a bona fide Ca(2+)-activated chloride channel that is activated by intracellular Ca(2+) and Ca(2+)-mobilizing stimuli. With eight putative transmembrane domains and no apparent similarity to previously characterized channels, ANO1 defines a new family of ionic channels. The biophysical properties as well as the pharmacological profile of ANO1 are in full agreement with native Ca(2+)-activated chloride currents. ANO1 is expressed in various secretory epithelia, the retina and sensory neurons. Furthermore, knockdown of mouse Ano1 markedly reduced native Ca(2+)-activated chloride currents as well as saliva production in mice. We conclude that ANO1 is a candidate Ca(2+)-activated chloride channel that mediates receptor-activated chloride currents in diverse physiological processes.