Channel Inhibitor Research Articles

P27 Chloride intracellular channel 4 is a global regulator of type 1 interferon signalling in systemic sclerosis skin

Abstract Introduction and aims Systemic sclerosis (SSc) is an autoimmune disease in which an immune-related injury induces fibrosis of the skin and can progress to affect the internal organs in the most serve cases. Aberrant type 1 interferon (IFN) signalling in the keratinocytes plays a major role in SSc disease progression. We have previously shown the chloride intracellular channel 4 (CLIC)4 is upregulated in SSc skin fibroblasts and plays an important role in SSc fibrosis by enhancing transforming growth factor-β signalling. In this study, we investigated the role of CLIC4 in SSc keratinocyte biology. Methods Skin biopsies from patients with SSc (N = 6) and healthy controls (HCs) (N = 6) were analysed by immunohistochemistry for the expression of CLIC4 and phosphorylated signal transducer and activator of transcription (STAT)1. The skin keratinocyte cell line HaCaTs was stimulated with a range of type 1 IFN signalling agonists including POLY I:C, POLY dA:dT, ODN 2216 and IFN-α. CLIC4 was inhibited with the chloride channel inhibitors NPPB and IAA-94 or small interfering RNA specific to CLIC4. Conditioned media from HC or SSc dermal fibroblasts was employed for indirect coculture of HaCaTs. Results Skin biopsies from SSc showed high levels of CLIC4 in SSc skin fibroblasts, keratinocytes and endothelial cells compared with HC. Indirect coculture of HaCaTs with SSc fibroblast media induced CLIC4 expression in the HaCaTs. The increased CLIC4 expression played an important role in type 1 IFN signalling in keratinocytes as inhibition of CLIC4 blocked Toll-like receptor (TLR)3, TLR9 and cGAS-mediated activation of the type 1 IFN signalling pathway transcription factor STAT1. Additionally, inhibition of CLIC4 prevented SSc fibroblast media from inducing a type 1 IFN response in keratinocytes. Conclusions The data presented in this study suggests that CLIC4 is a global regulator of the type 1 IFN signalling cascade in SSc epithelial cells.

Synapse-specific trapping of SNARE machinery proteinsin the anesthetized Drosophila brain.

General anesthetics disrupt brain network dynamics through multiple pathways, in part through post-synaptic potentiation of inhibitory ion channels as well as pre-synaptic inhibition of neuroexocytosis. Common clinical general anesthetic drugs, such as propofol and isoflurane, have been shown to interact and interfere with core components of the exocytic release machinery to cause impaired neurotransmitter release. Recent studies however suggest that these drugs do not affect all synapse subtypes equally. We investigated the role of the presynaptic release machinery in multiple neurotransmitter systems under isoflurane general anesthesia in the adult female Drosophila brain using live-cell super resolution microscopy and optogenetic readouts of exocytosis and neural excitability. We activated neurotransmitter-specific mushroom body output neurons (MBONs) and imaged presynaptic function under isoflurane anesthesia. We found that isoflurane impaired synaptic release and presynaptic protein dynamics in excitatory cholinergic synapses. In contrast, isoflurane had little to no effect on inhibitory GABAergic or glutamatergic synapses. These results present a distinct inhibitory mechanism for general anesthesia, whereby neuroexocytosis is selectively impaired at excitatory synapses, while inhibitory synapses remain functional. This suggests a presynaptic inhibitory mechanism that complements the other inhibitory effects of these drugs.Significance Statement General anesthetics are promiscuous drugs that act on a variety of pre-synaptic and post-synaptic proteins. Yet they produce a common endpoint - loss of behavioral responsiveness - in all animals. Using optogenetic techniques to measure functional readouts in identified neurons in the Drosophila brain, we have found that the volatile anesthetic isoflurane impairs neurotransmitter release from excitatory synapses, and that this is associated with immobilization of release machinery proteins. Inhibitory synapses were unaffected. This suggests a level of presynaptic specificity to the anesthetic's mechanism of action which complements the other known effects on synaptic function, and potentially explains how some of these drugs might work to produce the common endpoint termed general anesthesia.

Lipid-derived electrophiles inhibit the function of membrane channels during ferroptosis

The therapeutic targeting of ferroptosis requires full understanding of the molecular mechanism of this regulated cell death pathway. While lipid-derived electrophiles (LDEs), including 4-hydroxy-2-nonenal (4-HNE), are important biomarkers of ferroptosis, a functional role for these highly reactive species in ferroptotic cell death execution has not been established. Here, through mechanistic characterization of LDE-detoxification impairment, we demonstrate that LDEs mediate altered protein function during ferroptosis. Applying live cell fluorescence imaging, we first identified that export of glutathione-LDE-adducts through multidrug resistance-associated protein (MRP) channels is inhibited following exposure to a panel of ferroptosis inducers (FINs) with different modes of action (type I-IV FINs erastin, RSL3, FIN56, and FINO2). This channel inhibition was recreated by both initiation of lipid peroxidation and treatment with 4-HNE. Importantly, treatment with radical-trapping antioxidants prevented impaired LDE-adduct export when working with both FINs and lipid peroxidation initiators but not 4-HNE, pinpointing LDEs as the cause of this inhibited MRP activity observed during ferroptosis. Our findings, when combined with reports of widespread LDE alkylation of key proteins following ferroptosis induction, including MRP1, set a precedent for LDEs as critical mediators of ferroptotic cell damage. Lipid hydroperoxide breakdown to form truncated phospholipids and LDEs may fully explain membrane permeabilization and modified protein function downstream of lipid peroxidation, offering a unified explanation of the molecular cell death mechanism of ferroptosis.

Synthesis and Biological Evaluation of a Voltage-Gated Sodium Channel Inhibitor

Synthesis and Biological Evaluation of a Voltage-Gated Sodium Channel Inhibitor

Peripherally targeted analgesia via AAV-mediated sensory neuron-specific inhibition of multiple pronociceptive sodium channels.

This study reports that targeting intrinsically disordered regions of NaV1.7 protein facilitates discovery of sodium channel inhibitory peptide aptamers (NaViPA) for adeno-associated virus (AAV)-mediated, sensory neuron-specific analgesia. A multipronged inhibition of INa1.7, INa1.6, INa1.3, and INa1.1. but not INa1.5 and INa1.8 was found for a prototype, named NaViPA1, which was derived from the NaV1.7 intracellular loop 1 and is conserved among the TTXs NaV subtypes. NaViPA1 expression in primary sensory neurons (PSNs) of dorsal root ganglia (DRG) produced significant inhibition of TTXs INa but not TTXr INa. DRG injection of AAV6-encoded NaViPA1 significantly attenuated evoked and spontaneous pain behaviors in both male and female rats with neuropathic pain induced by tibial nerve injury (TNI). Whole-cell current clamp of the PSNs showed that NaViPA1 expression normalized PSN excitability in TNI rats, suggesting that NaViPA1 attenuated pain by reversal of injury-induced neuronal hypersensitivity. Immunohistochemistry revealed efficient NaViPA1 expression restricted in PSNs and their central and peripheral terminals, indicating PSN-restricted AAV biodistribution. Inhibition of sodium channels by NaViPA1 was replicated in the human iPSC-derived sensory neurons. These results summate that NaViPA1 is a promising analgesic lead that, combined with AAV-mediated PSN-specific block of multiple TTXs NaVs, has potential as peripheral nerve-restricted analgesic therapeutics.

Direct Inhibition of BK Channels by Cannabidiol, One of the Principal Therapeutic Cannabinoids Derived from Cannabis sativa.

Cannabidiol (CBD), one of the main Cannabis sativa bioactive compounds, is utilized in the treatment of major epileptic syndromes. Its efficacy can be attributed to a multimodal mechanism of action that includes, as potential targets, several types of ion channels. In the brain, CBD reduces the firing frequency in rat hippocampal neurons, partly prolonging the duration of action potentials, suggesting a potential blockade of voltage-operated K+ channels. We postulate that this effect might involve the inhibition of the large-conductance voltage- and Ca2+-operated K+ channel (BK channel), which plays a role in the neuronal action potential's repolarization. Thus, we assessed the impact of CBD on the BK channel activity, heterologously expressed in HEK293 cells. Our findings, using the patch-clamp technique, revealed that CBD inhibits BK channel currents in a concentration-dependent manner with an IC50 of 280 nM. The inhibition is through a direct interaction, reducing both the unitary conductance and voltage-dependent activation of the channel. Additionally, the cannabinoid significantly delays channel activation kinetics, indicating stabilization of the closed state. These effects could explain the changes induced by CBD in action potential shape and duration, and they may contribute to the observed anticonvulsant activity of this cannabinoid.

Epithelium-derived 6-nitrodopamine modulates noradrenaline-induced contractions in human seminal vesicles

AimsTo evaluate the basal release of 6-nitrodopamine (6-ND) from human isolated seminal vesicles (HISV) and to characterize its action and origin. Main methodsLeft HISV obtained from patients undergoing prostatectomy surgery was suspended in a 3-mL organ bath containing warmed (37 °C) and gassed (95%O2:5%CO2) Krebs-Henseleit's solution (KHS) with ascorbic acid. An aliquot of 2 mL of the supernatant was used to quantify catecholamines by LC-MS/MS. For functional studies, concentration-responses curves to catecholamines were obtained, and pEC50 and Emax values were calculated. Detection of tyrosine hydroxylase and S100 protein were also carried out by both immunohistochemistry and fluorescence in-situ hybridization assays (FISH). Key findingsBasal release of 6-ND was higher than the other catecholamines (14.76 ± 14.54, 4.99 ± 6.92, 3.72 ± 4.35 and 5.13 ± 5.76 nM for 6-ND, noradrenaline, adrenaline, and dopamine, respectively). In contrast to the other catecholamines, the basal release of 6-ND was not affected by the sodium current (Nav) channel inhibitor tetrodotoxin (1 μM; 10.4 ± 8.9 and 10.4 ± 7.9 nM, before and after tetrodotoxin, respectively). All the catecholamines produced concentration-dependent HISV contractions (pEC50 4.1 ± 0.2, 4.9 ± 0.3, 5.0 ± 0.3, and 3.9 ± 0.8 for 6-ND, noradrenaline, adrenaline, and dopamine, respectively), but 6-ND was 10-times less potent than noradrenaline and adrenaline. However, preincubation with very low concentration of 6-ND (10−8 M, 30 min) produced significant leftward shifts of the concentration-response curves to noradrenaline. Immunohistochemical and FISH assays identified tyrosine hydroxylase in tissue epithelium of HISV strips. SignificanceEpithelium-derived 6-ND is the major catecholamine released from human isolated seminal vesicles and that modulates smooth muscle contractility by potentiating noradrenaline-induced contractions.

Loss of anoctamin 1 reveals a subtle role for BK channels in lymphatic muscle action potentials.

Ca2+ signalling plays a crucial role in determining lymphatic muscle cell excitability and contractility through its interaction with the Ca2+-activated Cl- channel anoctamin 1 (ANO1). In contrast, the large-conductance (BK) Ca2+-activated K+ channel (KCa) and other KCa channels have prominent vasodilatory actions by hyperpolarizing vascular smooth muscle cells. Here, we assessed the expression and contribution of the KCa family to mouse and rat lymphatic collecting vessel contractile function. The BK channel was the only KCa channel consistently expressed in fluorescence-activated cell sorting-purified mouse lymphatic muscle cell lymphatic muscle cells. We used a pharmacological inhibitor of BK channels, iberiotoxin, and small-conductance Ca2+-activated K+ channels, apamin, to inhibit KCa channels acutely in ex vivo isobaric myography experiments and intracellular membrane potential recordings. In basal conditions, BK channel inhibition had little to no effect on either mouse inguinal-axillary lymphatic vessel (MIALV) or rat mesenteric lymphatic vessel contractions or action potentials (APs). We also tested BK channel inhibition under loss of ANO1 either by genetic ablation (Myh11CreERT2-Ano1 fl/fl, Ano1ismKO) or by pharmacological inhibition with Ani9. In both Ano1ismKO MIALVs and Ani9-pretreated MIALVs, inhibition of BK channels increased contraction amplitude, increased peak AP and broadened the peak of the AP spike. In rat mesenteric lymphatic vessels, BK channel inhibition also abolished the characteristic post-spike notch, which was exaggerated with ANO1 inhibition, and significantly increased the peak potential and broadened the AP spike. We conclude that BK channels are present and functional on mouse and rat lymphatic muscle cells but are otherwise masked by the dominance of ANO1. KEY POINTS: Mouse and rat lymphatic muscle cells express functional BK channels. BK channels make little contribution to either rat or mouse lymphatic collecting vessel contractile function in basal conditions across a physiological pressure range. ANO1 limits the peak membrane potential achieved in the action potential and sets a plateau potential limiting the voltage-dependent activation of BK. BK channels are activated when ANO1 is absent or blocked and slightly impair contractile strength by reducing the peak membrane potential achieved in the action potential spike and accelerating the post-spike repolarization.

Voltage-dependent anion channels are involved in the maintenance of pig sperm quality during liquid preservation

Pigs are usually bred through artificial insemination with liquid semen preserved at 15–20 °C. While this method of preservation brings many benefits, including a greater reproductive performance compared to frozen-thawed sperm, the period of storage is a limiting factor. As the mitochondrion regulates many facets of sperm physiology, modulating its activity could have an impact on their lifespan. Aligned with this hypothesis, the present study sought to investigate whether inhibition of voltage-dependent anion channels (VDACs), which reside in the outer mitochondrial membrane and regulate the flux of ions between mitochondria and the cytosol in somatic cells, influences the resilience of pig sperm to liquid preservation at 17 °C. For this purpose, semen samples (N = 7) were treated with two different concentrations of TRO19622 (5 μM and 50 μM), an inhibitor of VDACs, and stored at 17 °C for 10 days. At days 0, 4 and 10, sperm quality and functionality parameters were evaluated by flow cytometry and computer-assisted sperm analysis (CASA). The effects of inhibiting VDACs depended on the concentration of the inhibitor. On the one hand, the greatest concentration of TRO19622 (50 μM) led to a decrease in sperm motility, viability and mitochondrial membrane potential, which could be related to the observed intracellular Ca2+ increase. In contrast, total sperm motility was higher in samples treated with 5 μM TRO19622 than in the control, suggesting that when VDACs channels are inhibited by the lowest concentration of the blocking agent the resilience of pig sperm to liquid storage increases. In conclusion, the current research indicates that mitochondrial function, as regulated by ion channels in the outer mitochondrial membrane like VDACs, is related to the sperm resilience to liquid preservation and may influence cell lifespan.

Effects of Different Surface Functionalizations of Silica Nanoparticles on Mesenchymal Stem Cells.

Physicochemical properties of nanoparticles, such as particle size, surface charge, and particle shape, have a significant impact on cell activities. However, the effects of surface functionalization of nanoparticles with small chemical groups on stem cell behavior and function remain understudied. Herein, we incorporated different chemical functional groups (amino, DETA, hydroxyl, phosphate, and sulfonate with charges of +9.5, + 21.7, -14.1, -25.6, and -37.7, respectively) to the surface of inorganic silica nanoparticles. To trace their effects on mesenchymal stem cells (MSCs) of rat bone marrow, these functionalized silica nanoparticles were used to encapsulate Rhodamine B fluorophore dye. We found that surface functionalization with positively charged and short-chain chemical groups facilitates cell internalization and retention of nanoparticles in MSCs. The endocytic pathway differed among functionalized nanoparticles when tested with ion-channel inhibitors. Negatively charged nanoparticles mainly use lysosomal exocytosis to exit cells, while positively charged nanoparticles can undergo endosomal escape to avoid scavenging. The cytotoxic profiles of these functionalized silica nanoparticles are still within acceptable limits and tolerable. They exerted subtle effects on the actin cytoskeleton and migration ability. Last, phosphate-functionalized nanoparticles upregulate osteogenesis-related genes and induce osteoblast-like morphology, implying that it can direct MSCs lineage specification for bone tissue engineering. Our study provides insights into the rational design of biomaterials for effective drug delivery and regenerative medicine.

Inhibiting Nav1.7 channels in pulpitis: An in vivo study on neuronal hyperexcitability

Pulpitis constitutes a significant challenge in clinical management due to its impact on peripheral nerve tissue and the persistence of chronic pain. Despite its clinical importance, the correlation between neuronal activity and the expression of voltage-gated sodium channel 1.7 (Nav1.7) in the trigeminal ganglion (TG) during pulpitis is less investigated. The aim of this study was to examine the relationship between experimentally induced pulpitis and Nav1.7 expression in the TG and to investigate the potential of selective Nav1.7 modulation to attenuate TG abnormal activity associated with pulpitis. Acute pulpitis was induced at the maxillary molar (M1) using allyl isothiocyanate (AITC). The mice were divided into three groups: control, pulpitis model, and pulpitis model treated with ProTx-II, a selective Nav1.7 channel inhibitor. After three days following the surgery, we conducted a recording and comparative analysis of the neural activity of the TG utilizing in vivo optical imaging. Then immunohistochemistry and Western blot were performed to assess changes in the expression levels of extracellular signal-regulated kinase (ERK), c-Fos, collapsin response mediator protein-2 (CRMP2), and Nav1.7 channels. The optical imaging result showed significant neurological excitation in pulpitis TGs. Nav1.7 expressions exhibited upregulation, accompanied by signaling molecular changes suggestive of inflammation and neuroplasticity. In addition, inhibition of Nav1.7 led to reduced neural activity and subsequent decreases in ERK, c-Fos, and CRMP2 levels. These findings suggest the potential for targeting overexpressed Nav1.7 channels to alleviate pain associated with pulpitis, providing practical pain management strategies.

Effect of Intrathecal Eugenol on Cerebral Vasospasm in an Experimental Subarachnoid Hemorrhage Model

Eugenol has various curative properties. It affects the dilatation of cerebral arteries by voltage-dependent Ca2+ channel inhibition. This study is the first to explore the impact of eugenol on neuroprotection and vasospasm in an experimental subarachnoid hemorrhage (SAH) model. Twenty-four adult male Sprague-Dawley rats were indiscriminately separated into 3 groups: the control group (n = 8), the SAH group (n = 8), and the eugenol group (n = 8). A double bleeding method was used. The eugenol group received intracisternal eugenol (Sigma-Aldrich, St. Louis, MO, USA) at 30μg/20μl after induction of SAH. On the 7th day, all groups were euthanized. Measurements were taken for basilar artery wall thickness, lumen diameter, serum endothelin-1, and caspase-3 levels. The eugenol group exhibited significantly lower wall thickness, endothelin-1, oxidative stress index, and caspase-3 levels compared to the SAH group. In comparison to the control group, the eugenol group showed a higher oxidative stress index along with higher endothelin-1, and caspase-3 levels, but these differences were not statistically significant. Wall thickness was significantly higher in the eugenol group than in the control group. This study represents the first literature exploration of intrathecal eugenol's impact on vasospasm induced after experimental SAH. Administration of intrathecal eugenol demonstrates a positive effect on treatment of experimental vasospasm, as well as on reduction of oxidative stress and apoptosis.

Modeling the effect of magnetoelectric nanoparticles on neuronal electrical activity: An analog circuit approach.

This paper introduces a physical neuron model that incorporates magnetoelectric nanoparticles (MENPs) as an essential electrical circuit component to wirelessly control local neural activity. Availability of such a model is important as MENPs, due to their magnetoelectric effect, can wirelessly and noninvasively modulate neural activity, which, in turn, has implications for both finding cures for neurological diseases and creating a wireless noninvasive high-resolution brain-machine interface. When placed on a neuronal membrane, MENPs act as magnetic-field-controlled finite-size electric dipoles that generate local electric fields across the membrane in response to magnetic fields, thus allowing to controllably activate local ion channels and locally initiate an action potential. Herein, the neuronal electrical characteristic description is based on ion channel activation and inhibition mechanisms. A MENP-based memristive Hodgkin-Huxley circuit model is extracted by combining the Hodgkin-Huxley model and an equivalent circuit model for a single MENP. In this model, each MENP becomes an integral part of the neuron, thus enabling wireless local control of the neuron's electric circuit itself. Furthermore, the model is expanded to include multiple MENPs to describe collective effects in neural systems.

Mechanisms of cadmium absorption in Suaeda heteroptera roots

Heavy metal contaminated soil is a common environmental pollution problem, which has a negative impact. The potential for the phytoremediation has been widely recognized. This study investigated the mechanisms of cadmium (Cd) absorption in Suaeda heteroptera Kitag., a dominant wetland plant in northern China. A hydroponic experiment was carried out to determine the Cd content in S. heteroptera roots after adding ion channel inhibitors and metabolic inhibitors. Furthermore, subcellular distribution and chemical forms of Cd in S. heteroptera were investigated. The results showed that Cd was mainly absorbed by S. heteroptera roots through calcium ion channels. Cd absorption by S. heteroptera roots was closely associated with the P-type ATPase, suggesting that Cd was actively absorbed by S. heteroptera roots. Cell wall precipitation and vacuole compartmentalization were the major mechanisms underlying absorption and tolerance to Cd. Cd in S. heteroptera root system was predominantly bound to proteins, pectinate, and phosphates, thereby reducing its toxicity. However, Cd was transformed into a highly active form and became more toxic at high concentrations.

Unique electrophysiological property of a novel Nav1.7, Nav1.8, and Nav1.9 sodium channel blocker, ANP-230

Voltage-gated sodium channel subtypes, Nav1.7, Nav1.8, and Nav1.9 are predominantly expressed in peripheral sensory neurons. Recent genetic studies have revealed that they are involved in pathological pain processing and that the blockade of Nav1.7, Nav1.8, or Nav1.9 will become a promising pharmacotherapy especially for neuropathic pain. A growing number of drug discovery programs have targeted either of the subtypes to obtain a selective inhibitor which can provide pain relief without affecting the cardiovascular and central nervous systems, though none of them has been approved yet. Here we describe the in vitro characteristics of ANP-230, a novel sodium channel blocker under clinical development. Surprisingly, ANP-230 was shown to block three pain-related subtypes, human Nav1.7, Nav1.8, and Nav1.9 with similar potency, but had only low inhibitory activity to human cardiac Nav1.5 channel and rat central Nav channels. The voltage clamp experiments using different step pulse protocols revealed that ANP-230 had a “tonic block” mode of action without state- and use-dependency. In addition, ANP-230 caused a depolarizing shift of the activation curve and decelerated gating kinetics in human Nav1.7-stably expressing cells. The depolarizing shift of activation curve was commonly observed in human Nav1.8-stably expressing cells as well as rat dorsal root ganglion neurons. These data suggested a quite unique mechanism of Nav channel inhibition by ANP-230. Finally, ANP-230 reduced excitability of rat dorsal root ganglion neurons in a concentration dependent manner. Collectively, these promising results indicate that ANP-230 could be a potent drug for neuropathic pain.

Stimulation of Insulin Secretion and Inhibition of KATP Channels by Afzelechin and Coniferaldehyde from Ensete glaucum Seeds

Stimulation of Insulin Secretion and Inhibition of KATP Channels by Afzelechin and Coniferaldehyde from Ensete glaucum Seeds

Exploration and structure–activity relationship research of benzenesulfonamide derivatives as potent TRPV4 inhibitors for treating acute lung injury

RN-9893, a TRPV4 antagonist identified by Renovis Inc., showcased notable inhibition of TRPV4 channels. This research involved synthesizing and evaluating three series of RN-9893 analogues for their TRPV4 inhibitory efficacy. Notably, compounds 1b and 1f displayed a 2.9 to 4.5-fold increase in inhibitory potency against TRPV4 (IC50 = 0.71 ± 0.21 μM and 0.46 ± 0.08 μM, respectively) in vitro, in comparison to RN-9893 (IC50 = 2.07 ± 0.90 μM). Both compounds also significantly outperformed RN-9893 in TRPV4 current inhibition rates (87.6 % and 83.2 % at 10 μM, against RN-9893′s 49.4 %). For the first time, these RN-9893 analogues were profiled in an in vivo mouse model, where intraperitoneal injections of 1b or 1f at 10 mg/kg notably mitigated symptoms of acute lung injury induced by lipopolysaccharide (LPS). These outcomes indicate that compounds 1b and 1f are promising candidates for acute lung injury treatment.

Isolation, Identification and in-Silico Characterization of Bioactive Peptide from the Venom Sac of Conus inscriptus

Nature has been the source of new medications since ancient times, and at least half of all commercialised pharmaceuticals have been made from renewable resources to treat various illnesses, including pain, inflammation, and infection. In recent years, interest has risen in bioprospecting of new bioactive peptides, especially for medical and health-related applications. Therefore, the production of functional meals is starting to get recognition for its potential to enhance quality of life when combined with a healthy lifestyle. In view of this, the current work aimed to isolate, purify, and identify bioactive peptides from Conus inscriptus venom sac protein extracts, with an emphasis on antioxidant and anti-inflammatory properties. The findings reveal that the DPPH radical scavenging activity, albumin denaturation, and HRBC membrane stabilisation inhibition activities of Conus inscriptus venom sac crude protein extracts are 23.76±2.4, 66.23±3.1, and 57.32±2.6% respectively. Secondary screening of purified protein fractions obtained through sephadex G100 gel filtration exhibited increased anti-inflammatory efficacy from fractions 19 to 23. Electrophoresis and PMF analysis revealed that the purified anti-inflammatory peptide was homogenous with a molecular weight of 12 KDa, and it was identified as a conotoxin MI15b precursor. The 3D model of conotoxin exhibits the highest similarity with template c6nk9A with a confidence of 54.1%, and its function was predicted as a potassium ion channel inhibitor. The findings of the Insilco characterisation of the conotoxin MI15b precursor concluded that this protein might serve as an anti-inflammatory agent and may be responsible for therapeutic actions in the medical management of many inflammatory-related disorders.

H2SIncreases Blood Pressure via Activation of L-Type Calcium Channels with Mediation by HS•Generated from Reactions with Oxyhemoglobin.

Although the gasotransmitter hydrogen sulfide (H2S) is well known for its vasodilatory effects, H2S also exhibits vasoconstricting properties. Herein, it is demonstrated that administration of H2S as intravenous sodium sulfide (Na2S) increased blood pressure in sheep and rats, and this effect persisted after H2S has disappeared from the blood. Inhibition of the L-type calcium channel (LTCC) diminished the hypertensive effects. Incubation of Na2S with whole blood, red blood cells, methemoglobin, or oxyhemoglobin produced a hypertensive product of H2S, which is not hydrogen thioperoxide, metHb-SH- complexes, per-/poly- sulfides, or thiolsulfate, but rather a labile intermediate. One-electron oxidation of H2S by oxyhemoglobin generated its redox cousin, sulfhydryl radical (HS•). Consistent with the role of HS• as the hypertensive intermediate, scavenging HS• inhibited Na2S-induced vasoconstriction and activation of LTCCs. In conclusion, H2S causes vasoconstriction that is dependent on the activation of LTCCs and generation of HS• by oxyhemoglobin.

Ayurvedic and Chinese Herbs against Coronaviruses.

COVID-19 is a viral disease that infects the lower airways, causing severe acute respiratory syndrome (SARS) and fatal pneumonia. The ripple effect of the COVID-19 outbreak has created serious problems in the healthcare systems of many countries and had far-reaching consequences for the global economy. Thus, effective control measures should be implemented for this coronavirus infection in the future. The ongoing episode of the SARS-CoV-2 sickness, COVID-19, in China, and the subsequent irregular spread of contamination to different nations, has alarmed the clinical and academic community primarily due to the deadly nature of this disease. Being a newly identified virus in the viral classification and having the highest mutation rate, rapid therapeutics are not readily available for treating this ailment, leading to the widespread of the disease and causing social issues for affected individuals. Evidence of Ayurveda and traditional Chinese medicine (TCM) has been found in ancient civilizations, such as those of the Hindus, Babylonians, Hebrews, and Arabs. Although TCM and Ayurvedic herbs do not promise to be very effective treatments for this pandemic, they can reduce infectivity and virulence by enhancing immunity and showing effectiveness in rehabilitation after COVID-19 disease. Thus, they could be used as sources of inhibitor molecules for certain phenomena, such as viral replication, attachment to the host, 3CL protease inhibition, 3a ion channel inhibitors, and reverse transcription inhibition. Medicinal plants from TCM and Ayurveda and their biologically active phytoconstituents can effectively modulate the targets and pathways relevant to inflammation and immune responses in human bodies. The present review analyzes the role of certain TCM and Ayurvedic medicinal plants in healing COVID-19 infection. Medicinal plants such as Glycyrrhiza glabra (licorice), Curcuma longa (turmeric), and Zingiber officinale (ginger) are regarded as the main antiviral herbs. Their extracts and individual bioactive compounds could be used as potential substances for developing remedies to prevent or cure the coronavirus disease. Generally, antiviral phytochemicals obtained from natural sources are considered potent candidates for fighting COVID-19 infection and rehabilitation after it.