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Biomass carbon has the advantages of wide source, low cost and environmental protection, and has been widely used in the field of electrochemical energy storage. In this work, N and S co-doped carbon materials were prepared by using peanut shell as carbon source and thiourea as activator. When the peanut shell and activator were 2 g and 4 g, respectively, the prepared NSPC-4 had the largest specific surface area and special pore structure. Elemental analysis showed that the activator introduced more N, S and O atoms to the carbon material, and more heteroatoms helped to improve the surface structure of the carbon material and provide additional pseudocapacitance. In addition, NSPC-4 contains a short-range ordered graphite structure, which can provide excellent electrical conductivity. The electrochemical test results show that NSPC-4 has the largest specific capacitance. When the mass of the activator is higher than or below 4 g, the electrochemical performance of the carbon material will be reduced. The symmetric supercapacitor (SSC) assembled by NSPC-4 has an energy density of 8.3 Wh kg -1 when the power density is 350 W kg -1 . The synthesis method is not only simple, green and economical, but also has important application value., (© 2024 Wiley-VCH GmbH.)

Vincristine-induced peripheral neuropathy is a common side effect of vincristine treatment, which is accompanied by pain and can be dose-limiting. The molecular mechanisms that underlie vincristine-induced pain are not well understood. We have established an animal model to investigate pathophysiological mechanisms of vincristine-induced pain. Our previous studies have shown that the tetrodotoxin-sensitive voltage-gated sodium channel Nav1.6 in medium-diameter dorsal root ganglion (DRG) neurons contributes to the maintenance of vincristine-induced allodynia. In this study, we investigated the effects of vincristine administration on excitability in small-diameter DRG neurons and whether the tetrodotoxin-resistant (TTX-R) Nav1.8 channels contribute to mechanical allodynia. Current-clamp recordings demonstrated that small DRG neurons become hyper-excitable following vincristine treatment, with both reduced current threshold and increased firing frequency. Using voltage-clamp recordings in small DRG neurons, we now show an increase in TTX-R current density and a -7.3 mV hyperpolarizing shift in the half-maximal potential (V1/2) of activation of Nav1.8 channels in vincristine-treated animals, which likely contributes to the hyperexcitability that we observed in these neurons. Notably, vincristine treatment did not enhance excitability of small DRG neurons from Nav1.8 knockout mice, and the development of mechanical allodynia was delayed but not abrogated in these mice. Together, our data suggest that sodium channel Nav1.8 in small DRG neurons contributes to the development of vincristine-induced mechanical allodynia., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Replacement of expensive and rare platinum with metal-nitrogen-carbon catalysts for oxygen reduction reactions in proton exchange membrane fuel cells is hindered by their inferior activity. Herein, we report a highly active iron-nitrogen-carbon catalyst by optimizing the carbon structure and coordination environments of Fe-N 4 sites. A critical high-temperature treatment with ammonium chloride and ammonium bromide not only enhances the intrinsic activity and density of Fe-N 4 sites, but also introduces numerous defects, trace Br ions and creates mesopores in the carbon framework. Notably, surface Br ions significantly improve the interaction between the ionomer and catalyst particles, promoting ionomer infiltration and optimizing the O 2 transport and charge transfer at triple-phase boundary. This catalyst delivers a high peak power density of 1.86 W cm -2 and 54 mA cm -2 at 0.9 V iR-free in a H 2 -O 2 fuel cells at 80 °C. Our findings highlight the critical role of interface microenvironment regulation., (© 2024. The Author(s).)

In pursuing cheap and effective oxygen reduction catalysts, the Fe/N/C system emerges as a promising candidate. Nevertheless, the structural transformations of starting materials into Fe- and N-doped carbon catalysts remains poorly characterized under pyrolytic conditions. Here, we explore the evolution of Fe species and track the formation of Fe-N 4 site development by employing diverse in-situ diagnostic techniques. In-situ heating microscopy reveals the initial formation of FeO x nanoparticles and subsequent internal migration within the carbon matrix, which stops once FeO x is fully reduced. The migration and decomposition of nanoparticles then leads to carbon layer reconstruction. Experimental and theoretical analysis reveals size-dependent behavior of FeO x where nanoparticles below 7 nm readily release Fe atoms to form Fe-N 4 while nanoparticles with sizes >10 nm tend to coalesce and impede Fe-N 4 site formation. The work visualizes the pyrolysis process of Fe/N/C materials, providing theoretical guidance for the rational design of catalysts., (© 2024. The Author(s).)

Proton exchange membrane fuel cells (PEMFCs) and alkaline membrane fuel cells (AEMFCs) have received great attention as energy devices of the next generation. Accelerating oxygen reduction reaction (ORR) kinetics is the key to improve PEMFC and AEMFC performance. Platinum-based catalysts are the most widely used catalysts for the ORR, but their high price and low abundance limit the commercialization of fuel cells. Non-noble metal-nitrogen-carbon (M-N-C) is considered to be the most likely material class to replace Pt-based catalysts, among which Fe-N-C and Co-N-C have been widely studied due to their excellent intrinsic ORR performance and have made great progress in the past decades. With the improvement of synthesis technology and a deeper understanding of the ORR mechanism, some reported Fe-N-C and Co-N-C catalysts have shown excellent ORR activity close to that of commercial Pt/C catalysts. Inspired by the progress, regulation strategies for Fe-N-C and Co-N-C catalysts are summarized in this Review from 5 perspectives: (1) coordinated atoms, (2) environmental heteroatoms and defects, (3) dual-metal active sites, (4) metal-based particle promoters, and (5) curved carbon layers. We also make suggestions on some challenges facing Fe-N-C and Co-N-C research., (© 2024 Wiley-VCH GmbH.)

The single-atom Fe-N-C is a prominent material with exceptional reactivity in areas of sustainable energy and catalysis research. It is challenging to obtain the dense Fe-N 4 site without the Fe nanoparticles (NPs) sintering during the Fe-N-C synthesis via high-temperature pyrolysis. Thus, a novel approach is devised for the Fe-N-C synthesis at low temperatures. Taking FeCl 2 as Fe source, a hydrogen environment can facilitate oxygen removal and dichlorination processes in the synthesis, efficiently favouring Fe-N 4 site formation without Fe NPs clustering at as low as 360 °C. We shed light on the reaction mechanism about hydrogen promoting Fe-N 4 formation in the synthesis. By adjusting the temperature and duration, the Fe-N 4 structural evolution and site density can be precisely tuned to directly influence the catalytic behaviour of the Fe-N-C material. The FeNC-H 2 -360 catalyst demonstrates a remarkable Fe dispersion (8.3 wt %) and superior acid ORR activity with a half-wave potential of 0.85 V and a peak power density of 1.21 W cm -2 in fuel cell. This method also generally facilitates the synthesis of various high-performance M-N-C materials (M=Fe, Co, Mn, Ni, Zn, Ru) with elevated single-atom loadings., (© 2024 Wiley-VCH GmbH.)

The exorbitant cost of Pt-based electrocatalysts and the poor durability of non-noble metal electrocatalysts for proton exchange membrane fuel cells limited their practical application. Here, FeN 4 active sites electronically coupled with PtFe alloys (PtFe-FeNC) were successfully prepared by a vapor deposition strategy as an ultralow Pt loading (0.64 wt %) hybrid electrocatalyst. The FeN 4 sites on the FeNC matrix are able to effectively anchor the PtFe alloys, thus inhibiting their aggregation during long-life cycling. These PtFe alloys, in turn, can efficiently restrain the leaching of the FeN 4 sites from the FeNC matrix. Thus, the PtFe-FeNC demonstrated an improved Pt mass activity of 2.33 A mg Pt -1 at 0.9 V toward oxygen reduction reaction, which is 12.9 times higher than that of commercial Pt/C (0.18 A mg Pt -1 ). It demonstrated great stability, with the Pt mass activity decreasing by only 9.4% after 70,000 cycles. Importantly, the fuel cell with an ultralow Pt loading in the cathode (0.012 mg Pt cm -2 ) displays a high Pt mass activity of 1.75 A mg Pt -1 at 0.9 V iR -free , which is significantly better than commercial MEA (0.25 A mg Pt -1 ). Interestingly, PtFe-FeNC catalysts possess enhanced durability, exhibiting a 12.5% decrease in peak power density compared to the 51.7% decrease of FeNC.

Enhancing the density and utilization of FeN 4 sites can serve as a viable approach to enhance the catalytic efficacy of iron nitrogen carbon (FeNC) catalysts for oxygen reduction reaction (ORR). Herein, we present a plasma-assisted method for enhancing the porosity of nitrogen-doped carbon. Our findings indicate that the ideal ratio of mesopore to micropore area is 0.463. This ratio not only promotes the diffusion of Fe 3+ but also creates additional active sites for Fe 3+ loading, leading to an increase in the number of available FeN 4 sites in FeNC electrocatalysts during pyrolysis. The density (76.5 μmol g -1 ) and utilization (21.08 %) of d-FeNC-30 are significantly higher than those of FeNC without plasma treatment, with a 2.8-fold and 2-fold increase, respectively. Remarkably, it displays outstanding performance, evidenced by a half-wave potential of 0.835 V (vs. RHE) in a 0.1 M HClO 4 solution and a power density of 0.860 W cm -2 in proton exchange membrane fuel cells (PEMFCs). The developed plasma-assisted approach for improving the site density (SD) and utilization of FeN 4 provides a new perspective for high-performance ORR FeNC catalysts., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Naja atra bite is one of the most common severe snakebites in emergency departments. Unfortunately, the pathophysiological changes caused by Naja atra bite are unclear due to the lack of good animal models. In this study, an animal model of Naja atra bite in Guangxi Bama miniature pigs was established by intramuscular injection at 2 mg/kg of Naja atra venom, and serum metabolites were systematically analyzed using untargeted metabolomic and targeted metabolomic approaches. Untargeted metabolomic analysis revealed that 5045 chromatographic peaks were obtained in ESI+ and 3871 chromatographic peaks were obtained in ESI-. Screening in ESI+ modes and ESI- modes identified 22 and 36 differential metabolites compared to controls. The presence of 8 core metabolites of glutamine, arginine, proline, leucine, phenylalanine, inosine, thymidine and hippuric acid in the process of Naja atra bite was verified by targeted metabolomics significant difference (P<0.05). At the same time, during the verification process of the serum clinical samples with Naja atra bite, we found that the contents of three metabolites of proline, phenylalanine and inosine in the serum of the patients were significantly different from those of the normal human serum (P<0.05). By conducting functional analysis of core and metabolic pathway analysis, we revealed a potential correlation between changes in key metabolites after the Naja atra bite and the resulting pathophysiological alterations, and our research aims to establish a theoretical foundation for the prompt diagnosis and treatment of Naja atra bite., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 He et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

To achieve the Fe-N-C materials with both high activity and durability in proton exchange membrane fuel cells, the attack of free radicals on Fe-N 4 sites must be overcome. Herein, we report a strategy to effectively eliminate radicals at the source to mitigate the degradation by anchoring CeO 2 nanoparticles as radicals scavengers adjacent (Sca ad-CeO2 ) to the Fe-N 4 sites. Radicals such as ⋅OH and HO 2 ⋅ that form at Fe-N 4 sites can be instantaneously eliminated by adjacent CeO 2 , which shortens the survival time of radicals and the regional space of their damage. As a result, the CeO 2 scavengers in Fe-NC/Sca ad-CeO2 achieved ∼80 % elimination of the radicals generated at the Fe-N 4 sites. A fuel cell prepared with the Fe-NC/Sca ad-CeO2 showed a smaller peak power density decay after 30,000 cycles determined with US DOE PGM-relevant AST, increasing the decay of Fe-NC Phen from 69 % to 28 % decay., (© 2023 Wiley-VCH Verlag GmbH.)

In electrochemical ethanol oxidation reactions (EOR) catalyzed by Pt metal nanoparticles through a C2 route, the dissociation of the C-C bond in the ethanol molecule can be a limiting factor. Complete EOR processes producing CO 2 were always exemplified by the oxidative dehydrogenation of C1 intermediates, a reaction route with less energy utilization efficiency. Here, we report a Pt 3 Ga/C electrocatalyst with a uniform distribution of Ga over the nanoparticle surface for EOR that produces CO 2 at medium potentials (>0.3 V vs SCE) efficiently through direct and sustainable oxidation of C2 intermediate species, i.e., acetaldehyde. We demonstrate the excellent performance of the Pt 3 Ga-200/C catalyst by using electrochemical in situ Fourier transform infrared reflection spectroscopy (FTIR) and an isotopic labeling method. The atomic interval structure between Pt and Ga makes the surface of nanoparticles nonensembled, avoiding the formation of poisonous *CH x and *CO species via bridge-type adsorption of ethanol molecules. Meanwhile, the electron redistribution from Ga to Pt diminishes the *O/*OH adsorption and CO poisoning on Pt atoms, exposing more available sites for interaction with the C2 intermediates. Furthermore, the dissociation of H 2 O into *OH is facilitated by the high hydrophilicity of Ga, which is supported by DFT calculations, promoting the deep oxidation of C2 intermediates. Our work represents an extremely rare EOR process that produces CO 2 without observing kinetic limitations under medium potential conditions.

Background: Bungarus multicinctus is one of the most dangerous venomous snakes prone to cardiopulmonary damage with extremely high mortality. In our previous work, we found that glutamine (Gln) and glutamine synthetase (GS) in pig serum were significantly reduced after Bungarus multicinctus bite. In the present study, to explore whether there is a link between the pathogenesis of cardiopulmonary injury and Gln metabolic changes induced by Bungarus multicinctus venom. We investigated the effect of Gln supplementation on the lung and heart function after snakebite., Methods: We supplemented different concentrations of Gln to mice that were envenomated by Bungarus multicinctus to observe the biological behavior, survival rate, hematological and pathological changes. Gln was supplemented immediately or one hour after the venom injection, and then changes in Gln metabolism were analyzed. Subsequently, to further explore the protective mechanism of glutamine on tissue damage, we measured the expression of heat-shock protein70 (HSP70), NF-κB P65, P53/PUMA by western blotting and real-time polymerase in the lung and heart., Results: Gln supplementation delayed the envenoming symptoms, reduced mortality, and alleviated the histopathological changes in the heart and lung of mice bitten by Bungarus multicinctus . Additionally, Gln increased the activity of glutamine synthetase (GS), glutamate dehydrogenase (GDH) and glutaminase (GLS) in serum. It also balanced the transporter SLC7A11 expression in heart and lung tissues. Bungarus multicinctus venom induced the NF-κB nuclear translocation in the lung, while the HO-1 expression was suppressed. At the same time, venom activated the P53/PUMA signaling pathway and the BAX expression in the heart. Gln treatment reversed the above phenomenon and increased HSP70 expression., Conclusion: Gln alleviated the glutamine metabolism disorder and cardiopulmonary damage caused by Bungarus multicinctus venom. It may protect lungs and heart against venom by promoting the expression of HSP70, inhibiting the activation of NF-κB and P53/PUMA, thereby delaying the process of snake venom and reducing mortality. The present results indicate that Gln could be a potential treatment for Bungarus multicinctus bite., Competing Interests: Competing interests: The authors declare that they have no competing interests.

Voltage-gated sodium (Na V ) channels are critical regulators of neuronal excitability and are targeted by many toxins that directly interact with the pore-forming α subunit, typically via extracellular loops of the voltage-sensing domains, or residues forming part of the pore domain. Excelsatoxin A (ExTxA), a pain-causing knottin peptide from the Australian stinging tree Dendrocnide excelsa, is the first reported plant-derived Na V channel modulating peptide toxin. Here we show that TMEM233, a member of the dispanin family of transmembrane proteins expressed in sensory neurons, is essential for pharmacological activity of ExTxA at Na V channels, and that co-expression of TMEM233 modulates the gating properties of Na V 1.7. These findings identify TMEM233 as a previously unknown Na V 1.7-interacting protein, position TMEM233 and the dispanins as accessory proteins that are indispensable for toxin-mediated effects on Na V channel gating, and provide important insights into the function of Na V channels in sensory neurons., (© 2023. The Author(s).)

Chronic pain is highly prevalent and remains a significant unmet global medical need. As part of a search for modulatory genes that confer pain resilience, we have studied two family cohorts where one individual reported much less pain than other family members that share the same pathogenic gain-of-function Nav1.7 mutation that confers hyperexcitability on pain-signaling dorsal root ganglion (DRG) neurons. In each of these kindreds, the pain-resilient individual carried a gain-of-function variant in Kv7.2 or Kv7.3, two potassium channels that stabilize membrane potential and reduce excitability. Our observation in this molecular genetic study that these gain-of-function Kv7.2 and 7.3 variants reduce DRG neuron excitability suggests that agents that activate or open Kv7 channels should attenuate sensory neuron firing. In the present study, we assess the effects on sensory neuron excitability of three Kv7 modulators-retigabine (Kv7.2 thru Kv7.5 activator), ICA-110381 (Kv7.2/Kv7.3 specific activator), and as a comparator ML277 (Kv7.1 specific activator)-in a "human-pain-in-a-dish" model (human iPSC-derived sensory neurons, iPSC-SN). Multi-electrode-array (MEA) recordings demonstrated inhibition of firing with retigabine and ICA-110381 (but not with ML277), with the concentration-response curve indicating that retigabine can achieve a 50% reduction of firing with sub-micromolar concentrations. Current-clamp recording demonstrated that retigabine hyperpolarized iPSC-SN resting potential and increased threshold. This study implicates Kv7.2/Kv7.3 channels as effective modulators of sensory neuron excitability, and suggest that compounds that specifically target Kv7.2/Kv7.3 currents in sensory neurons, including human sensory neurons, might provide an effective approach toward pain relief., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Estacion, Liu, Cheng, Dib-Hajj and Waxman.)

Water disaster is one of the major disasters threatening the safety production of coal mine, which is rank only second to gas disaster. And Meisbluke Coal Mine is seriously affected by water disasters. In order to find out the scope and location of water-bearing areas in Meisbluke Coal Mine. The comprehensive geophysical exploration method combining transient electromagnetic method (TEM) and high-density resistivity method (HDRM) is used to carry out this research. Firstly, the measuring area is determined and the relevant measuring points are arranged, and 73 TEM survey lines and 10 HDRM survey lines were arranged according to the requirements. Then, the principle, data processing method and main parameters of TEM and HDRM are introduced. The TEM detection results show that the thickness of Quaternary inferred by TEM is consistent with the geological conditions revealed by boreholes, and the thickness is about 50-80 m. And the water enrichment of the bedrock is obviously recharged by the Quaternary aquifer. Besides, the water-enriched areas in each elevation are marked and the water inrush runoff channel is deduced based on the 3D scenario inverted by TEM. And the detection results of the water-bearing areas by the two methods are in good agreement with each other, which can confirm and complement each other, and the interpretation of the data is scientific and reasonable with high reliability. Besides, the detection depth of HDRM is larger than that of TEM., (© 2022. The Author(s).)

The non-dystrophic myotonias are inherited skeletal muscle disorders characterized by skeletal muscle stiffness after voluntary contraction, without muscle atrophy. Based on their clinical features, non-dystrophic myotonias are classified into myotonia congenita, paramyotonia congenita, and sodium channel myotonia. Using whole-exome next-generation sequencing, we identified a L703P mutation (c.2108T>C, p.L703P) in SCN4A in a Chinese family diagnosed with non-dystrophic myotonias. The clinical findings of patients in this family included muscle stiffness and hypertrophy. The biophysical properties of wildtype and mutant channels were investigated using whole-cell patch clamp. L703P causes both gain-of-function and loss-of-function changes in Nav1.4 properties, including decreased current density, impaired recovery, enhanced activation and slow inactivation. Our study demonstrates that L703P is a pathogenic variant for myotonia, and provides additional electrophysiological information for understanding the pathogenic mechanism of SCN4A-associated channelopathies., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)

Abstract: Gain-of-function and loss-of-function mutations in Nav1.7 cause chronic pain and pain insensitivity, respectively. The preferential expression of Nav1.7 in the peripheral nervous system and its role in human pain signaling make Nav1.7 a promising target for next-generation pain therapeutics. However, pharmacological agents have not fully recapitulated these pain phenotypes, and because of the lack of subtype-selective molecular modulators, the role of Nav1.7 in the perception of pain remains poorly understood. Scorpion venom is an excellent source of bioactive peptides that modulate various ion channels, including voltage-gated sodium (Nav) channels. Here, we demonstrate that Buthus martensii Karsch scorpion venom (BV) elicits pain responses in mice through direct enhancement of Nav1.7 activity and have identified Makatoxin-3, an α-like toxin, as a critical component for BV-mediated effects on Nav1.7. Blocking other Nav subtypes did not eliminate BV-evoked pain responses, supporting the pivotal role of Nav1.7 in BV-induced pain. Makatoxin-3 acts on the S3-S4 loop of voltage sensor domain IV (VSD4) of Nav1.7, which causes a hyperpolarizing shift in the steady-state fast inactivation and impairs inactivation kinetics. We also determined the key residues and structure-function relationships for the toxin-channel interactions, which are distinct from those of other well-studied α toxins. This study not only reveals a new mechanism underlying BV-evoked pain but also enriches our knowledge of key structural elements of scorpion toxins that are pivotal for toxin-Nav1.7 interactions, which facilitates the design of novel Nav1.7 selective modulators., (Copyright © 2021 International Association for the Study of Pain.)

In this work, the role of chitosan (CS) in improving the properties of bioactive glass (BG) paste for wound healing was studied. Based on in vitro evaluation, it was found that the addition of CS neutralizes the pH value from 11.0 to 7.5, which did not lead to decreasing the bioactivity of BG paste in vitro . The rheological properties showed that the composite paste had higher bio-adhesion and better affinity with the skin surface than either CS or the BG paste. The antibacterial property evaluation showed that the composite paste had stronger antibacterial activity than either CS or BG paste and promoted the proliferation of HUVECs (human umbilical vein endothelial cells) and HaCat (human immortalized keratinocyte cells). Comparatively, the effect of promoting the proliferation of HUVECs is more significant than that of HaCat. The burn-wound model of rat was developed for evaluating in vivo activity, and the addition of CS effectively promoted wound healing without obvious inflammation according to the IL-1β and IL-6 staining. This novel paste is expected to provide a promising alternative for wound healing.

Bungarus multicinctus is one of the top ten venomous snakes in China, and its bite causes acute and severe diseases, but its pathophysiology remains poorly elucidated. Thus, an animal model of Bungarus multicinctus bite was established by intramuscular injection of 30μg/kg of Bungarus multicinctus venom, and then the serum metabolites were subsequently screened, identified and validated by ultra-performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UPLC-Q-TOF-MS) methods to explore the potential biomakers and possible metabolic pathways. Untargeted metabolomics analysis showed that 36 and 38 endogenous metabolites levels changed in ESI+ and ESI-, respectively, KEGG pathway analysis showed that 5 metabolic pathways, including mineral absorption, central carbon metabolism in cancer, protein digestion and absorption, aminoacyl-tRNA biosynthesis and ABC transporters might be closely related to Bungarus multicinctus bite. Targeted metabolomics analysis showed that there were significant differences in serum D-proline, L-leucine and L-glutamine after Bungarus multicinctus bite (P < 0.05). In addition, receiver operating characteristic (ROC) analysis showed that the diagnostic efficiency of L-Glutamine was superior to other potential biomarkers and the AUC value was 0.944. Moreover, we found evidence for differences in the pathophysiology of glutamine between Bungarus multicinctus bite group and normal group, specifically with the content of glutamine synthetase (GS) and glutaminase (GLS). Taken together, the current study has successfully established an animal model of Bungarus multicinctus bite, and further identified the links between the metabolic perturbations and the pathophysiology and the potential diagnostic biomakers of Bungarus multicinctus bite, which provided valuable insights for studying the mechanism of Bungarus multicinctus bite., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)

The similarities and differences between nervous systems of various species result from developmental constraints and specific adaptations 1-4 . Comparative analyses of the prefrontal cortex (PFC), a cerebral cortex region involved in higher-order cognition and complex social behaviours, have identified true and potential human-specific structural and molecular specializations 4-8 , such as an exaggerated PFC-enriched anterior-posterior dendritic spine density gradient 5 . These changes are probably mediated by divergence in spatiotemporal gene regulation 9-17 , which is particularly prominent in the midfetal human cortex 15,18-20 . Here we analysed human and macaque transcriptomic data 15,20 and identified a transient PFC-enriched and laminar-specific upregulation of cerebellin 2 (CBLN2), a neurexin (NRXN) and glutamate receptor-δ GRID/GluD-associated synaptic organizer 21-27 , during midfetal development that coincided with the initiation of synaptogenesis. Moreover, we found that species differences in level of expression and laminar distribution of CBLN2 are, at least in part, due to Hominini-specific deletions containing SOX5-binding sites within a retinoic acid-responsive CBLN2 enhancer. In situ genetic humanization of the mouse Cbln2 enhancer drives increased and ectopic laminar Cbln2 expression and promotes PFC dendritic spine formation. These findings suggest a genetic and molecular basis for the anterior-posterior cortical gradient and disproportionate increase in the Hominini PFC of dendritic spines and a developmental mechanism that may link dysfunction of the NRXN-GRID-CBLN2 complex to the pathogenesis of neuropsychiatric disorders., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)

Tailoring the near-surface composition of Pt-based alloy can optimize the surface chemical properties of a nanocatalyst and further improve the sluggish H 2 electrooxidation performance in an alkaline electrolyte. However, the construction of alloy nanomaterials with a precise near-surface composition and smaller particle size still needs to overcome huge obstacles. Herein, ultra-small PtRu 3 binary nanoparticles (<2 nm) evenly distributed on porous carbon (PtRu 3 /PC), with different near-surface atomic compositions (Pt-increased and Ru-increased), are successfully synthesized. XPS characterizations and electrochemical test confirm the transformation of a near-surface atomic composition after annealing PtRu 3 /PC-300 alloy; when annealing in CO atmosphere, forming the Pt-increased near-surface structure (500 °C), while the Ru-increased near-surface structure appears in an Ar heat treatment process (700 °C). Furthermore, three PtRu 3 /PC nanocatalysts all weaken the hydrogen binding strength relative to the Pt/PC. Remarkably, the Ru-increased nanocatalyst exhibits up to 38.8-fold and 9.2-fold HOR improvement in mass activity and exchange current density, compared with the Pt/PC counterpart, respectively. CO-stripping voltammetry tests demonstrate the anti-CO poisoning ability of nanocatalysts, in the sequence of Ru-increased ≥ PtRu 3 /PC-300 > Pt-increased > Pt/PC. From the perspective of engineering a near-surface structure, this study may open up a new route for the development of high-efficiency electrocatalysts with a strong electronic effect and oxophilic effect., (© 2021 Wiley-VCH GmbH.)

Peripheral neuropathy is associated with enhanced activity of primary afferents which is often manifested as pain. Voltage-gated sodium channels (VGSCs) are critical for the initiation and propagation of action potentials and are thus essential for the transmission of the noxious stimuli from the periphery. Human peripheral sensory neurons express multiple VGSCs, including Nav1.7, Nav1.8, and Nav1.9 that are almost exclusively expressed in the peripheral nervous system. Distinct biophysical properties of Nav1.7, Nav1.8, and Nav1.9 underlie their differential contributions to finely tuned neuronal firing of nociceptors, and mutations in these channels have been associated with several inherited human pain disorders. Functional characterization of these mutations has provided additional insights into the role of these channels in electrogenesis in nociceptive neurons and pain sensation. Peripheral tissue damage activates an inflammatory response and triggers generation and release of inflammatory mediators, which can act through diverse signaling cascades to modulate expression and activity of ion channels including VGSCs, contributing to the development and maintenance of pathological pain conditions. In this review, we discuss signaling pathways that are activated by pro-nociceptive inflammatory mediators that regulate peripheral sodium channels, with a specific focus on direct phosphorylation of these channels by multiple protein kinases., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Stimuli-responsive smart photosensitizer (PS) nanoassemblies that allow enhanced delivery and controlled release of PSs are promising for imaging-guided photodynamic therapy (PDT) of tumors. However, the lack of high-sensitivity and spatial-resolution signals and fast washout of released PSs from tumor tissues have impeded PDT efficacy in vivo. Herein, we report tumor targeting, redox-responsive magnetic and fluorogenic PS nanoassemblies (NP-RGD) synthesized via self-assembly of a cRGD- and disulfide-containing fluorogenic and paramagnetic small molecule (1-RGD) for fluorescence/magnetic resonance bimodal imaging-guided tumor PDT. NP-RGD show high r 1 relaxivity but quenched fluorescence and PDT activity; disulfide reduction by glutathione (GSH) promotes efficient disassembly into a small-molecule probe (2-RGD) and an organic PS (PPa-SH), which could further bind with intracellular albumin, allowing prolonged retention and cascade activation of fluorescence and PDT to ablate tumors., (© 2020 Wiley-VCH GmbH.)

Noninvasive in vivo imaging of hepatic glutathione (GSH) levels is essential to early diagnosis and prognosis of acute hepatitis. Although GSH-responsive fluorescence imaging probes have been reported for evaluation of hepatitis conditions, the low penetration depth of light in liver tissue has impeded reliable GSH visualization in the human liver. We present a liver-targeted and GSH-responsive trimodal probe (GdNPs-Gal) for rapid evaluation of lipopolysaccharide- (LPS-) induced acute liver inflammation via noninvasive, real-time in vivo imaging of hepatic GSH depletion. GdNPs-Gal are formed by molecular coassembly of a GSH-responsive Gd(III)-based MRI probe (1-Gd) and a liver-targeted probe (1-Gal) at a mole ratio of 5/1 (1-Gd/1-Gal), which shows high r 1 relaxivity with low fluorescence and fluorine magnetic resonance spectroscopic ( 19 F-MRS) signals. Upon interaction with GSH, 1-Gd and 1-Gal are cleaved and GdNPs-Gal rapidly disassemble into small molecules 2-Gd, 2-Gal, and 3, producing a substantial decline in r 1 relaxivity with compensatory enhancements in fluorescence and 19 F-MRS. By combining in vivo magnetic resonance imaging ( 1 H-MRI) with ex vivo fluorescence imaging and 19 F-MRS analysis, GdNPs-Gal efficiently detect hepatic GSH using three independent modalities. We noninvasively visualized LPS-induced liver inflammation and longitudinally monitored its remediation in mice after treatment with an anti-inflammatory drug, dexamethasone (DEX). Findings highlight the potential of GdNPs-Gal for in vivo imaging of liver inflammation by integrating molecular coassembly with GSH-driven disassembly, which can be applied to other responsive molecular probes for improved in vivo imaging., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 Yuxuan Hu et al.)

In this work, 1 GHz video data was collected by a CMOS camera and successfully transmitted by the electro-optic (EO) modulator driven by an external modulation module integrated onto the same chip. For this application, the EO modulator component included a polymer waveguide modulator, which performed a 20 GHz bandwidth, clear eye diagram opening with a Q factor of 10.3 at 32 Gbit/s and a drive voltage of 1.5 V pp . By utilizing a thermally stable EO polymer, the wide-band polymer modular can yield a photonic integrated camera sensor system which is a reliable processing platform for real-time data processing.

P2X receptors are a family of extracellular ATP-gated trimeric cation channels that is widely distributed in human tissues. Quite some drug candidates targeting P2X receptors have entered into preclinical or main phases of clinical trials, but many of them failed due to low subtype-selectivity or species differences in pharmacological activities between human and experimental animals. Here, we identified the distinct inhibitory efficacies of NF110, a competitive inhibitor, between the rat (rP2X3) and human (hP2X3) P2X3 receptors. We demonstrated that this difference is determined by two amino acids located in the dorsal fin (DF) domain of P2X3 receptors. As revealed by mutagenesis, metadynamics, and covalent modification, NF110-mediated rP2X3 inhibition may be through a filling in the cavity formed by the DF, left flipper (LF) and lower body (LB) to partially, rather than fully, occupy the ATP-binding pocket. Moreover, substitution of residues located in the DF and/or LF domains of the rP2X2 receptor, a NF110-insensitive subtype, with the equivalent amino acids of rP2X3, bestowed the sensitivity of rP2X2 to NF110. The critical roles of the DF and LF domains in channel gating of P2X and low conservativity in residue sequences of those two domains raise the possibility that small molecules differentially interacting with the residues of the DF and LF domains of different P2X receptors may modulate channel's activity in a subtype-selective manner. However, the possible species-specificity of P2X inhibitors/modulators makes it more complex when interpreting the preclinical data into clinical researches. Nevertheless, our data provide new insights into the subtype-selectivity of competitive inhibitors and their distinct potencies in the human and experimental animals, both of which are extremely important in the drug discovery of P2X receptors., (Copyright © 2018 Science China Press. Published by Elsevier B.V. All rights reserved.)

Voltage-gated sodium channels Na V 1.7, Na V 1.8 and Na V 1.9 have been the focus for pain studies because their mutations are associated with human pain disorders, but the role of Na V 1.6 in pain is less understood. In this study, we selectively knocked out Na V 1.6 in dorsal root ganglion (DRG) neurons, using Na V 1.8-Cre directed or adeno-associated virus (AAV)-Cre mediated approaches, and examined the specific contribution of Na V 1.6 to the tetrodotoxin-sensitive (TTX-S) current in these neurons and its role in neuropathic pain. We report here that Na V 1.6 contributes up to 60% of the TTX-S current in large, and 34% in small DRG neurons. We also show Na V 1.6 accumulates at nodes of Ranvier within the neuroma following spared nerve injury (SNI). Although Na V 1.8-Cre driven Na V 1.6 knockout does not alter acute, inflammatory or neuropathic pain behaviors, AAV-Cre mediated Na V 1.6 knockout in adult mice partially attenuates SNI-induced mechanical allodynia. Additionally, AAV-Cre mediated Na V 1.6 knockout, mostly in large DRG neurons, significantly attenuates excitability of these neurons after SNI and reduces Na V 1.6 accumulation at nodes of Ranvier at the neuroma. Together, Na V 1.6 in Na V 1.8-positive neurons does not influence pain thresholds under normal or pathological conditions, but Na V 1.6 in large Na V 1.8-negative DRG neurons plays an important role in neuropathic pain.

Voltage-gated sodium channel Nav1.7 is a key molecule in nociception, and its dysfunction has been associated with various pain disorders. Here, we investigated the regulation of Nav1.7 biophysical properties by Fyn, an Src family tyrosine kinase. Nav1.7 was coexpressed with either constitutively active (Fyn CA ) or dominant negative (Fyn DN ) variants of Fyn kinase. Fyn CA elevated protein expression and tyrosine phosphorylation of Nav1.7 channels. Site-directed mutagenesis analysis identified two tyrosine residues (Y1470 and Y1471) located within the Nav1.7 DIII-DIV linker (L3) as phosphorylation sites of Fyn. Whole-cell recordings revealed that Fyn CA evoked larger changes in Nav1.7 biophysical properties when expressed in ND7/23 cells than in Human Embryonic Kidney (HEK) 293 cells, suggesting a cell type-specific modulation of Nav1.7 by Fyn kinase. In HEK 293 cells, substitution of both tyrosine residues with phenylalanine dramatically reduced current amplitude of mutant channels, which was partially rescued by expressing mutant channels in ND7/23 cells. Phenylalanine substitution showed little effect on Fyn CA -induced changes in Nav1.7 activation and inactivation, suggesting additional modifications in the channel or modulation by interaction with extrinsic factor(s). Our study demonstrates that Nav1.7 is a substrate for Fyn kinase, and the effect of the channel phosphorylation depends on the cell background. Fyn-mediated modulation of Nav1.7 may regulate DRG neuron excitability and contribute to pain perception. Whether this interaction could serve as a target for developing new pain therapeutics requires future study.

Key Points: Paramyotonia congenita is a hereditary channelopathy caused by missense mutations in the SCN4A gene, which encodes the α subunit of the human skeletal muscle voltage-gated sodium channel NaV1.4. Affected individuals suffered from myotonia and paralysis of muscles, which were aggravated by exposure to cold. We report a three-generation Chinese family with patients presenting paramyotonia congenita and identify a novel N1366S mutation of NaV1.4. Whole-cell electrophysiological recordings of the N1366S channel reveal a gain-of-function change of gating in response to cold. Modelling and molecular dynamic simulation data suggest that an arginine-to-serine substitution at position 1366 increases the distance from N1366 to R1454 and disrupts the hydrogen bond formed between them at low temperature. We demonstrate that N1366S is a disease-causing mutation and that the temperature-sensitive alteration of N1366S channel activity may be responsible for the pronounced paramyotonia congenita symptoms of these patients., Abstract: Paramyotonia congenita is an autosomal dominant skeletal muscle channelopathy caused by missense mutations in SCN4A, the gene encoding the α subunit of the human skeletal muscle voltage-gated sodium channel NaV1.4. We report a three-generation family in which six members present clinical symptoms of paramyotonia congenita characterized by a marked worsening of myotonia by cold and by the presence of clear episodes of paralysis. We identified a novel mutation in SCN4A (Asn1366Ser, N1366S) in all patients in the family but not in healthy relatives or in 500 normal control subjects. Functional analysis of the channel protein expressed in HEK293 cells by whole-cell patch clamp recording revealed that the N1366S mutation led to significant alterations in the gating process of the NaV1.4 channel. The N1366S mutant displayed a cold-induced hyperpolarizing shift in the voltage dependence of activation and a depolarizing shift in fast inactivation, as well as a reduced rate of fast inactivation and accelerated recovery from fast inactivation. In addition, homology modelling and molecular dynamic simulation of N1366S and wild-type NaV1.4 channels indicated that the arginine-to-serine substitution disrupted the hydrogen bond formed between N1366 and R1454. Together, our results suggest that N1366S is a gain-of-function mutation of NaV1.4 at low temperature and the mutation may be responsible for the clinical symptoms of paramyotonia congenita in the affected family and constitute a basis for studies into its pathogenesis., (© 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.)

The coupling intensity modulator based on a triple-microring structure was proposed and numerically investigated for a high speed and a low bit error ratio (BER) operation. The modulator consists of a dual-microring optical cavity and a gate-microring energy feedback path. The optical cavity ensures a high energy storing efficiency, and the feedback path enables modulation with little intracavity energy decay. The bandwidth of 103 GHz and modulation depth of 6.2 dB at 2.0 Vpp were theoretically verified by the analysis of the sinusoidal modulation performance. Pulse modulation resulted in a data rate of 160 Gbps, an extinction ratio of 16.84 dB, and a BER of 1 × 10 -8 . The proposed modulator is applicable for compact, high-speed, and low-energy photonic integration.

The current knowledge about heat nociception is mainly confined to the thermosensors, including the transient receptor potential cation channel V1 expressed in the nociceptive neurons of dorsal root ganglion (DRG). However, the loss of thermosensors only partially impairs heat nociception, suggesting the existence of undiscovered mechanisms. We found that the loss of an intracellular fibroblast growth factor (FGF), FGF13, in the mouse DRG neurons selectively abolished heat nociception. The noxious heat stimuli could not evoke the sustained action potential firing in FGF13-deficient DRG neurons. Furthermore, FGF13 interacted with the sodium channel Na v 1.7 in a heat-facilitated manner. FGF13 increased Na v 1.7 sodium currents and maintained the membrane localization of Na v 1.7 during noxious heat stimulation, enabling the sustained firing of action potentials. Disrupting the FGF13/Na v 1.7 interaction reduced the heat-evoked action potential firing and nociceptive behavior. Thus, beyond the thermosensors, the FGF13/Na v 1.7 complex is essential for sustaining the transmission of noxious heat signals., (Copyright © 2017 Elsevier Inc. All rights reserved.)

A novel tubular NiO nanostructure was synthesized by a facile and low-cost hydrothermal strategy and then further functionalized by decorating α-Fe2O3 nanorods. The images of electron microscopy indicated that the α-Fe2O3 nanorods were assembled epitaxially on the surfaces of NiO nanotubes to form α-Fe2O3/NiO nanotubes. As a proof-of-concept demonstration of the function, gas sensing devices were fabricated from as-prepared α-Fe2O3/NiO nanotubes, and showed enhanced gas response and excellent selectivity toward toluene, giving a response of 8.8 to 5 ppm target gas, which was about 7.8 times higher than that of pure NiO nanotubes at 275 °C. The improved gas sensing performance of α-Fe2O3/NiO nanotubes could be attributed to the unique tubular morphology features, p-n heterojunctions and the synergetic behavior of α-Fe2O3 and NiO.

Mutations of the neuronal sodium channel gene SCN8A are associated with lethal movement disorders in the mouse and with human epileptic encephalopathy. We describe a spontaneous mouse mutation, Scn8a(9J), that is associated with a chronic movement disorder with early onset tremor and adult onset dystonia. Scn8a(9J) homozygotes have a shortened lifespan, with only 50% of mutants surviving beyond 6 months of age. The 3 bp in-frame deletion removes 1 of the 3 adjacent isoleucine residues in transmembrane segment DIVS6 of Nav1.6 (p.Ile1750del). The altered helical orientation of the transmembrane segment displaces pore-lining amino acids with important roles in channel activation and inactivation. The predicted impact on channel activity was confirmed by analysis of cerebellar Purkinje neurons from mutant mice, which lack spontaneous and induced repetitive firing. In a heterologous expression system, the activity of the mutant channel was below the threshold for detection. Observations of decreased nerve conduction velocity and impaired behavior in an open field are also consistent with reduced activity of Nav1.6. The Nav1.6Δ1750 protein is only partially glycosylated. The abundance of mutant Nav1.6 is reduced at nodes of Ranvier and is not detectable at the axon initial segment. Despite a severe reduction in channel activity, the lifespan and motor function of Scn8a(9J/9J) mice are significantly better than null mutants lacking channel protein. The clinical phenotype of this severe hypomorphic mutant expands the spectrum of Scn8a disease to include a recessively inherited, chronic and progressive movement disorder., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Induction of cytotoxic T lymphocytes (CTL) is critical to cancer vaccine based immunotherapy. Efforts to elicit CTLs against tumor MUC1 with peptide based vaccine have not been successful in clinical application. We have design a MUC1 vaccine by replacing B cell epitope of CTB with MUC1 VNTR peptide. Immunization with hybrid CTB-MUC1 plus aluminum hydroxide and CpG adujuvant (CTB-MUC1-Alum-CpG) induce MUC1-specific CTLs in mice. Moreover, this vaccination can prevent tumor growth and reduce tumor burden in MUC1+B16 mice model. Meanwhile, CTB-MUC1-Alum-CpG vaccination can promote Th1 cells and CD8+ T cells inflate to tumor tissue. Our approach might be applicable to other cancer vaccine design.

The regulation and mechanisms underlying itch sensation are complex. Here, we report a role for acid-sensing ion channel 3 (ASIC3) in mediating itch evoked by certain pruritogens during tissue acidosis. Co-administration of acid with Ser-Leu-Ile-Gly-Arg-Leu-NH2 (SL-NH2) increased scratching behavior in wild-type, but not ASIC3-null, mice, implicating the channel in coincident detection of acidosis and pruritogens. Mechanistically, SL-NH2 slowed desensitization of proton-evoked currents by targeting the previously identified nonproton ligand-sensing domain located in the extracellular region of ASIC3 channels in primary sensory neurons. Ablation of the ASIC3 gene reduced dry-skin-induced scratching behavior and pathological changes under conditions with concomitant inflammation. Taken together, our data suggest that ASIC3 mediates itch sensation via coincident detection of acidosis and nonproton ligands that act at the nonproton ligand-sensing domain of the channel., (Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.)

Hierarchical α-Fe2O3/NiO composites with a hollow nanostructure were synthesized by a facile hydrothermal method. The structures and morphologies of the composites were investigated by different kinds of techniques, including X-ray diffraction, field-emission electron scanning microscopy, transmission electron microscopy, and energy dispersive spectroscopy. Hierarchical α-Fe2O3/NiO composites were fabricated by growing the α-Fe2O3 nanorods on the surfaces of porous NiO nanosheets with a thickness of ∼12 nm. The gas sensing properties of hierarchical α-Fe2O3/NiO composites toward toluene were investigated using a static system. The response of α-Fe2O3/NiO composites to 100 ppm toluene was ∼18.68, which was 13.18 times higher than that of pure NiO at 300 °C. The enhanced response can be attributed to heterojunction. Meanwhile, the rapid response and recovery characteristics were observed because of the porous hollow structural characteristics and catalytic actions of α-Fe2O3 and NiO.

Neuropathic pain is a chronic condition that is often refractory to treatment with available therapies and thus an unmet medical need. We have previously shown that the voltage-gated sodium channel Na(v)1.3 is upregulated in peripheral and central nervous system (CNS) of rats following nerve injury, and that it contributes to nociceptive neuron hyperexcitability in neuropathic conditions. To evaluate the therapeutic potential of peripheral Na(v)1.3 knockdown at a specific segmental level, we constructed adeno-associated viral (AAV) vector expressing small hairpin RNA against rat Na(v)1.3 and injected it into lumbar dorsal root ganglion (DRG) of rats with spared nerve injury (SNI). Our data show that direct DRG injection provides a model that can be used for proof-of-principle studies in chronic pain with respect to peripheral delivery route of gene transfer constructs, high transduction efficiency, flexibility in terms of segmental localization, and limited behavioral effects of the surgical procedure. We show that knockdown of Na(v)1.3 in lumbar 4 (L4) DRG results in an attenuation of nerve injury-induced mechanical allodynia in the SNI model. Taken together, our studies support the contribution of peripheral Na(v)1.3 to pain in adult rats with neuropathic pain, validate Na(v)1.3 as a target, and provide validation for this approach of AAV-mediated peripheral gene therapy.

Painful peripheral neuropathy often occurs without apparent underlying cause. Gain-of-function variants of sodium channel Na(v)1.7 have recently been found in ∼30% of cases of idiopathic painful small-fiber neuropathy. Here, we describe mutations in Na(v)1.8, another sodium channel that is specifically expressed in dorsal root ganglion (DRG) neurons and peripheral nerve axons, in patients with painful neuropathy. Seven Na(v)1.8 mutations were identified in 9 subjects within a series of 104 patients with painful predominantly small-fiber neuropathy. Three mutations met criteria for potential pathogenicity based on predictive algorithms and were assessed by voltage and current clamp. Functional profiling showed that two of these three Na(v)1.8 mutations enhance the channel's response to depolarization and produce hyperexcitability in DRG neurons. These observations suggest that mutations of Na(v)1.8 contribute to painful peripheral neuropathy.

Marked hypersensitivity to heat and mechanical (pressure) stimuli develop after a burn injury, but the neural mechanisms underlying these effects are poorly understood. In this study, we establish a new mouse model of focal second-degree burn injury to investigate the molecular and cellular basis for burn injury-induced pain. This model features robust injury-induced behavioral effects and tissue-specific altered cytokine profile, but absence of glial activation in spinal dorsal horn. Three voltage-gated sodium channels, Na(v)1.7, Na(v)1.8, and Na(v)1.9, are preferentially expressed in peripheral somatosensory neurons of the dorsal root ganglia (DRGs) and have been implicated in injury-induced neuronal hyperexcitability. Using knock-out mice, we provide evidence that Na(v)1.7 selectively contributes to burn-induced hypersensitivity to heat, but not mechanical, stimuli. After burn model injury, wild-type mice display increased sensitivity to heat stimuli, and a normally non-noxious warm stimulus induces activity-dependent Fos expression in spinal dorsal horn neurons. Strikingly, both effects are absent in Na(v)1.7 conditional knock-out (cKO) mice. Furthermore, burn injury increases density and shifts activation of tetrodotoxin-sensitive currents in a hyperpolarized direction, both pro-excitatory properties, in DRG neurons from wild-type but not Na(v)1.7 cKO mice. We propose that, in sensory neurons damaged by burn injury to the hindpaw, Na(v)1.7 currents contribute to the hyperexcitability of sensory neurons, their communication with postsynaptic spinal pain pathways, and behavioral thresholds to heat stimuli. Our results offer insights into the molecular and cellular mechanisms of modality-specific pain signaling, and suggest Na(v)1.7-blocking drugs may be effective in burn patients.

As ultrasound imagers become increasingly portable and lower cost, breakthroughs in transducer technology will be needed to provide high-resolution, real-time 3-D imaging while maintaining the affordability needed for portable systems. This paper presents a 32 x 32 ultrasound array prototype, manufactured using a CMUT-in-CMOS approach whereby ultrasonic transducer elements and readout circuits are integrated on a single chip using a standard integrated circuit manufacturing process in a commercial CMOS foundry. Only blanket wet-etch and sealing steps are added to complete the MEMS devices after the CMOS process. This process typically yields better than 99% working elements per array, with less than ±1.5 dB variation in receive sensitivity among the 1024 individually addressable elements. The CMUT pulseecho frequency response is typically centered at 2.1 MHz with a -6 dB fractional bandwidth of 60%, and elements are arranged on a 250 μm hexagonal grid (less than half-wavelength pitch). Multiplexers and CMOS buffers within the array are used to make on-chip routing manageable, reduce the number of physical output leads, and drive the transducer cable. The array has been interfaced to a commercial imager as well as a set of custom transmit and receive electronics, and volumetric images of nylon fishing line targets have been produced.

Neurons are highly polarized cells with functionally distinct axonal and somatodendritic compartments. Voltage-gated sodium channels Na(v)1.2 and Na(v)1.6 are highly enriched at axon initial segments (AISs) and nodes of Ranvier, where they are necessary for generation and propagation of action potentials. Previous studies using reporter proteins in unmyelinated cultured neurons suggest that an ankyrinG-binding motif within intracellular loop 2 (L2) of sodium channels is sufficient for targeting these channels to the AIS, but mechanisms of channel targeting to nodes remain poorly understood. Using a CD4-Na(v)1.2/L2 reporter protein in rat dorsal root ganglion neuron-Schwann cell myelinating cocultures, we show that the ankyrinG-binding motif is sufficient for protein targeting to nodes of Ranvier. However, reporter proteins cannot capture the complexity of full-length channels. To determine how native, full-length sodium channels are clustered in axons, and to show the feasibility of studying these channels in vivo, we constructed fluorescently tagged and functional mouse Na(v)1.6 channels for in vivo analysis using in utero brain electroporation. We show here that wild-type tagged-Na(v)1.6 channels are efficiently clustered at nodes and AISs in vivo. Furthermore, we show that mutation of a single invariant glutamic acid residue (E1100) within the ankyrinG-binding motif blocked Na(v)1.6 targeting in neurons both in vitro and in vivo. Additionally, we show that caseine kinase phosphorylation sites within this motif, while not essential for targeting, can modulate clustering at the AIS. Thus, the ankyrinG-binding motif is both necessary and sufficient for the clustering of sodium channels at nodes of Ranvier and the AIS.

A novel hardware design and preliminary experimental results for photoacoustic imaging are reported in this paper. This imaging system makes use of an infrared-transparent capacitive micromachined ultrasonic transducer (CMUT) chip for ultrasound reception and illuminates the image target through the CMUT array. The cascaded arrangement between the light source and transducer array allows for a more compact imager head and results in more uniform illumination. Taking advantage of the low optical absorption coefficient of silicon in the near infrared spectrum as well as the broad acoustic bandwidth that CMUTs provide, an infrared-transparent CMUT array has been developed for ultrasound reception. The center frequency of the polysilicon-membrane CMUT devices used in this photoacoustic system is 3.5 MHz, with a fractional bandwidth of 118% in reception mode. The silicon substrate of the CMUT array has been thinned to 100 μm and an antireflection dielectric layer is coated on the back side to improve the infrared-transmission rate. Initial results show that the transmission rate of a 1.06-μm Nd:Yag laser through this CMUT chip is 12%. This transmission rate can be improved if the thickness of silicon substrate and the thin-film dielectrics in the CMUT structure are properly tailored. Imaging of a metal wire phantom using this cascaded photoacoustic imager is demonstrated.

Individuals with severe, sporadic disorders of infantile onset represent an important class of disease for which discovery of the underlying genetic architecture is not amenable to traditional genetic analysis. Full-genome sequencing of affected individuals and their parents provides a powerful alternative strategy for gene discovery. We performed whole-genome sequencing (WGS) on a family quartet containing an affected proband and her unaffected parents and sibling. The 15-year-old female proband had a severe epileptic encephalopathy consisting of early-onset seizures, features of autism, intellectual disability, ataxia, and sudden unexplained death in epilepsy. We discovered a de novo heterozygous missense mutation (c.5302A>G [p.Asn1768Asp]) in the voltage-gated sodium-channel gene SCN8A in the proband. This mutation alters an evolutionarily conserved residue in Nav1.6, one of the most abundant sodium channels in the brain. Analysis of the biophysical properties of the mutant channel demonstrated a dramatic increase in persistent sodium current, incomplete channel inactivation, and a depolarizing shift in the voltage dependence of steady-state fast inactivation. Current-clamp analysis in hippocampal neurons transfected with p.Asn1768Asp channels revealed increased spontaneous firing, paroxysmal-depolarizing-shift-like complexes, and an increased firing frequency, consistent with a dominant gain-of-function phenotype in the heterozygous proband. This work identifies SCN8A as the fifth sodium-channel gene to be mutated in epilepsy and demonstrates the value of WGS for the identification of pathogenic mutations causing severe, sporadic neurological disorders., (Copyright © 2012 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)

Objective: Cerebellar dysfunction in multiple sclerosis (MS) contributes significantly to disability, is relatively refractory to symptomatic therapy, and often progresses despite treatment with disease-modifying agents. We previously observed that sodium channel Nav1.8, whose expression is normally restricted to the peripheral nervous system, is present in cerebellar Purkinje neurons in a mouse model of MS (experimental autoimmune encephalomyelitis [EAE]) and in humans with MS. Here, we tested the hypothesis that upregulation of Nav1.8 in cerebellum in MS and EAE has functional consequences contributing to symptom burden., Methods: Electrophysiology and behavioral assessment were performed in a new transgenic mouse model overexpressing Nav1.8 in Purkinje neurons. We also measured EAE symptom progression in mice lacking Nav1.8 compared to wild-type littermates. Finally, we administered the Nav1.8-selective blocker A803467 in the context of previously established EAE to determine reversibility of MS-like deficits., Results: We report that, in the context of an otherwise healthy nervous system, ectopic expression of Nav1.8 in Purkinje neurons alters their electrophysiological properties, and disrupts coordinated motor behaviors. Additionally, we show that Nav1.8 expression contributes to symptom development in EAE. Finally, we demonstrate that abnormal patterns of Purkinje neuron firing and MS-like deficits in EAE can be partially reversed by pharmacotherapy using a Nav1.8-selective blocker., Interpretation: Our results add to the evidence that a channelopathy contributes to cerebellar dysfunction in MS. Our data suggest that Nav1.8-specific blockers, when available for humans, merit study in MS., (Copyright © 2012 American Neurological Association.)

Objective: Small nerve fiber neuropathy (SFN) often occurs without apparent cause, but no systematic genetic studies have been performed in patients with idiopathic SFN (I-SFN). We sought to identify a genetic basis for I-SFN by screening patients with biopsy-confirmed idiopathic SFN for mutations in the SCN9A gene, encoding voltage-gated sodium channel Na(V)1.7, which is preferentially expressed in small diameter peripheral axons., Methods: Patients referred with possible I-SFN, who met the criteria of ≥2 SFN-related symptoms, normal strength, tendon reflexes, vibration sense, and nerve conduction studies, and reduced intraepidermal nerve fiber density (IENFD) plus abnormal quantitative sensory testing (QST) and no underlying etiology for SFN, were assessed clinically and by screening of SCN9A for mutations and functional analyses., Results: Twenty-eight patients who met stringent criteria for I-SFN including abnormal IENFD and QST underwent SCN9A gene analyses. Of these 28 patients with biopsy-confirmed I-SFN, 8 were found to carry novel mutations in SCN9A. Functional analysis revealed multiple gain of function changes in the mutant channels; each of the mutations rendered dorsal root ganglion neurons hyperexcitable., Interpretation: We show for the first time that gain of function mutations in sodium channel Na(V)1.7, which render dorsal root ganglion neurons hyperexcitable, are present in a substantial proportion (28.6%; 8 of 28) of patients meeting strict criteria for I-SFN. These results point to a broader role of Na(V)1.7 mutations in neurological disease than previously considered from studies on rare genetic syndromes, and suggest an etiological basis for I-SFN, whereby expression of gain of function mutant sodium channels in small diameter peripheral axons may cause these fibers to degenerate., (Copyright © 2011 American Neurological Association.)

Gain-of-function missense mutations of voltage-gated sodium channel Na(V)1.7 have been linked to the painful disorder inherited erythromelalgia. These mutations hyperpolarize activation, slow deactivation and enhance currents evoked by slow ramp stimuli (ramp currents). A correlation has recently been suggested between the age of onset of inherited erythromelalgia and the extent of hyperpolarizing shifts in mutant Na(V)1.7 channel activation; mutations causing large activation shifts have been linked to early age of onset inherited erythromelalgia, while mutations causing small activation shifts have been linked to age of onset within the second decade of life. Here, we report a family with inherited erythromelalgia with an in-frame deletion of a single residue--leucine 955 (Del-L955) in DII/S6. The proband did not show symptoms until the age of 15 years, and her affected mother only experienced mild symptoms during adolescence, which disappeared at the age of 38 years. Del-L955 shows no effect on Na(V)1.7 current density and fast inactivation, but causes an approximately -24 mV shift in activation, together with increases in amplitude of persistent currents and ramp currents. The mutation also produces an approximately -40 mV shift in slow inactivation, which reduces channel availability. Comparison of the effects of the Del-L955 mutation on dorsal root ganglion neuron hyperexcitability with those produced by another inherited erythromelalgia mutation (L858F) that does not enhance slow inactivation suggests that a delayed age of onset and milder symptoms in association with a large shift of channel activation, enhanced persistent and enhanced ramp currents may be related to the approximately -40 mV shift in slow inactivation for Del-L955, the largest shift thus far demonstrated in mutant Na(V)1.7 channels. Our results suggest that despite the pivotal role of activation shift in inherited erythromelalgia development, slow inactivation may regulate clinical phenotype by altering channel availability.

Voltage-dependent Ca(2+) (Ca(V)1.2) channels are the primary Ca(2+) influx pathway in arterial smooth muscle cells and are essential for contractility regulation by a variety of stimuli, including intravascular pressure. Arterial smooth muscle cell Ca(V)1.2 mRNA is alternatively spliced at exon 1 (e1), generating e1b or e1c variants, with e1c exhibiting relatively smooth muscle-specific expression in the cardiovascular system. Here, we examined physiological functions of Ca(V)1.2e1 variants and tested the hypothesis that targeting Ca(V)1.2e1 modulates resistance size cerebral artery contractility. Custom antibodies that selectively recognize Ca(V)1.2 channel proteins containing sequences encoded by either e1b (Ca(V)1.2e1b) or e1c (Ca(V)1.2e1c) both detected Ca(V)1.2 in rat and human cerebral arteries. shRNA targeting e1b or e1c reduced expression of that Ca(V)1.2 variant, induced compensatory up-regulation of the other variant, decreased total Ca(V)1.2, and reduced intravascular pressure- and depolarization-induced vasoconstriction. Ca(V)1.2e1b and Ca(V)1.2e1c knockdown reduced whole cell Ca(V)1.2 currents, with Ca(V)1.2e1c knockdown most effectively reducing total Ca(V)1.2 and inducing the largest vasodilation. Knockdown of α(2)δ-1, a Ca(V)1.2 auxiliary subunit, reduced surface expression of both Ca(V)1.2e1 variants, inhibiting Ca(V)1.2e1c more than Ca(V)1.2e1b. e1b or e1c overexpression reduced Ca(V)1.2 surface expression and whole cell currents, leading to vasodilation, with e1c overexpression inducing the largest effect. In summary, data indicate that arterial smooth muscle cells express Ca(V)1.2 channels containing e1b or e1c-encoded N termini that contribute to Ca(V)1.2 surface expression, α(2)δ-1 preferentially traffics the Ca(V)1.2e1c variant to the plasma membrane, and targeting of Ca(V)1.2e1 message or the Ca(V)1.2 channel proximal N terminus induces vasodilation.

Background: Nociception requires transduction and impulse electrogenesis in nerve fibers which innervate the body surface, including the skin. However, the molecular substrates for transduction and action potential initiation in nociceptors are incompletely understood. In this study, we examined the expression and distribution of Na+/Ca2+ exchanger (NCX) and voltage-gated sodium channel isoforms in intra-epidermal free nerve terminals., Results: Small diameter DRG neurons exhibited robust NCX2, but not NCX1 or NCX3 immunolabeling, and virtually all PGP 9.5-positive intra-epidermal free nerve terminals displayed NCX2 immunoreactivity. Sodium channel NaV1.1 was not detectable in free nerve endings. In contrast, the majority of nerve terminals displayed detectable levels of expression of NaV1.6, NaV1.7, NaV1.8 and NaV1.9. Sodium channel immunoreactivity in the free nerve endings extended from the dermal boundary to the terminal tip. A similar pattern of NCX and sodium channel immunolabeling was observed in DRG neurons in vitro., Conclusions: NCX2, as well as NaV1.6, NaV1.7, NaV1.8 and NaV1.9, are present in most intra-epidermal free nerve endings. The presence of NCX2, together with multiple sodium channel isoforms, in free nerve endings may have important functional implications.

Sodium channel Na(v)1.6 is essential for neuronal excitability in central and peripheral nervous systems. Loss-of-function mutations in Na(v)1.6 underlie motor disorders, with homozygous-null mutations causing juvenile lethality. Phosphorylation of Na(v)1.6 by the stress-induced p38 MAPK at a Pro-Gly-Ser(553)-Pro motif in its intracellular loop L1 reduces Na(v)1.6 current density in a dorsal root ganglion-derived cell line, without changing its gating properties. Phosphorylated Pro-Gly-Ser(553)-Pro motif is a putative binding site to Nedd4 ubiquitin ligases, and we hypothesized that Nedd4-like ubiquitin ligases may contribute to channel ubiquitination and internalization. We report here that p38 activation in hippocampal neurons from wild-type mice, but not from Scn8a(medtg) mice that lack Na(v)1.6, reduces tetrodotoxin-S sodium currents, suggesting isoform-specific modulation of Na(v)1.6 by p38 in these neurons. Pharmacological block of endocytosis completely abolishes p38-mediated Na(v)1.6 current reduction, supporting our hypothesis that channel internalization underlies current reduction. We also report that the ubiquitin ligase Nedd4-2 interacts with Na(v)1.6 via a Pro-Ser-Tyr(1945) motif in the C terminus of the channel and reduces Na(v)1.6 current density, and we show that this regulation requires both the Pro-Gly-Ser-Pro motif in L1 and the Pro-Ser-Tyr motif in the C terminus. Similarly, both motifs are necessary for p38-mediated reduction of Na(v)1.6 current, whereas abrogating binding of the ubiquitin ligase Nedd4-2 to the Pro-Ser-Tyr motif results in stress-mediated increase in Na(v)1.6 current density. Thus, phosphorylation of the Pro-Gly-Ser-Pro motif within L1 of Na(v)1.6 is necessary for stress-induced current modulation, with positive or negative regulation depending upon the availability of the C-terminal Pro-Ser-Tyr motif to bind Nedd4-2.