TMEM16A Research Articles

Knockdown of ANO1 decreases TGF-β- and IL-6-induced adhesion and migration of cardiac fibroblasts by inhibiting the expression of integrin and focal adhesion kinase

Ischemic cardiac injury triggers a significant inflammatory response, activating and mobilizing cardiac fibroblasts (CFs), which ultimately contributes to myocardial fibrosis. In this study, we investigated the role of ANO1, a calcium-activated chloride channel (CaCC) protein, in regulating CFs migration and adhesion under inflammatory conditions. Our results demonstrated that ANO1 knockdown significantly attenuated TGF-β- and IL-6-induced adhesion and migration of CFs. This inhibitory effect was mediated through the downregulation of integrin expression and reduced activation of focal adhesion kinase (FAK), key components in cellular adhesion and motility pathways. This study provides new insights into the mechanisms underlying CFs migration and adhesion, highlighting the potential of ANO1 as a therapeutic target for mitigating adverse fibrotic remodeling following myocardial infarction.

A quantitative analysis of bestrophin 1 cellular localization in mouse cerebral cortex.

Calcium-activated ligand-gated chloride channels, beyond their role in maintaining anion homeostasis, modulate neuronal excitability by facilitating nonvesicular neurotransmitter release. BEST1, a key member of this family, is permeable to γ-aminobutyric acid (GABA) and glutamate. While astrocytic BEST1 is well-studied and known to regulate neurotransmitter levels, its distribution and role in other brain cell types remain unclear. This study aimed to reassess the localization of BEST1 in the mouse cerebral cortex. We examined the localization and distribution of BEST1 in the mouse parietal cortex using light microscopy, confocal double-labeling with markers for astrocytes, neurons, microglia, and oligodendrocyte precursor cells, and 3D reconstruction techniques. In the cerebral cortex, BEST1 is more broadly distributed than previously thought. Neurons are the second most abundant BEST1+ cell type in the cerebral cortex, following astrocytes. BEST1 is diffusely expressed in neuronal somatic and neuropilar domains and is present at glutamatergic and GABAergic terminals, with a prevalence at GABAergic terminals. We also confirmed that BEST1 is expressed in cortical microglia and identified it in oligodendrocyte precursor cells, albeit to a lesser extent. Together, these findings suggest that BEST1's role in controlling neurotransmission may extend beyond astrocytes to include other brain cells. Understanding BEST1's function in these cells could offer new insights into the molecular mechanisms shaping cortical circuitry. Further research is needed to clarify the diverse roles of BEST1 in both normal and pathophysiological conditions.

The Tmem16a chloride channel is required for mucin maturation after secretion from goblet-like cells in the Xenopus tropicalis tadpole skin

The TMEM16A chloride channel is proposed as a therapeutic target in cystic fibrosis, where activation of this ion channel might restore airway surface hydration and mitigate respiratory symptoms. While TMEM16A is associated with increased mucin production under stimulated or pro-inflammatory conditions, its role in baseline mucin production, secretion and/or maturation is less well understood. Here, we use the Xenopus tadpole skin mucociliary surface as a model of human upper airway epithelium to study Tmem16a function in mucus production. We found that Xenopus tropicalis Tmem16a is present at the apical membrane surface of tadpole skin small secretory cells that express canonical markers of mammalian “goblet cells” such as Foxa1 and spdef. X. tropicalis Tmem16a functions as a voltage-gated, calcium-activated chloride channel when transfected into mammalian cells in culture. Depletion of Tmem16a from the tadpole skin results in dysregulated mucin maturation post-secretion, with secreted mucins having a disrupted molecular size distribution and altered morphology assessed by sucrose gradient centrifugation and electron microscopy, respectively. Our results show that in the Xenopus tadpole skin, Tmem16a is necessary for normal mucus barrier formation and demonstrate the utility of this model system to discover new biology relevant to human mucosal biology in health and disease.

Calcium-activated chloride channels. Role of potassium ions

Using the patch-clamp method in the whole-cell configuration, it was shownthat external potassium ions play an important role in the regulation of calcium-activated chloride currents. A clear dependence of the amplitude of chloride currents on changes in the concentration of external potassium is shown. Changes in concentration of sodium, magnesium and calcium ions from membrane outside have no so significant effect, like outside potassium ions. The effect of potassium on the amplitudes of chloride currents is significantly greater than the effect it has on other cell ionic currents — sodium, potassium, cation. There is reason to believe that a change in the amplitudes of chloride currents contributes to the pathophysiological processes characteristic of hypokalemia and hyperkalemia.

Amplification of olfactory transduction currents implements sparse stimulus encoding.

Sensory systems must perform the dual and opposing tasks of being sensitive to weak stimuli while also maintaining information content in dense and variable sensory landscapes. This occurs in the olfactory system, where OSNs are highly sensitive to low concentrations of odors and maintain discriminability in complex odor environments. How olfactory sensory neurons (OSNs) maintain both sensitivity and sparsity is not well understood. Here, we investigated whether the calcium-activated chloride channel, TMEM16B, may support these dual roles in OSNs. We used multiphoton microscopy to image the stimulus-response density of OSNs in the olfactory epithelium. In TMEM16B knockout mice, we found that sensory representations were denser, and the magnitude of OSN responses was increased. Behaviorally, these changes in sensory representations were associated with an increased aversion to the odorant trimethylamine, which switches perceptual valence as its concentration increases, and a decreased efficiency of olfactory-guided navigation. Together, our results indicate that the calcium-activated chloride channel TMEM16B sparsens sensory representations in the peripheral olfactory system and contributes to efficient integrative olfactory-guided behaviors.

TMEM16A regulates satellite cell-mediated skeletal muscle regeneration by ensuring a moderate level of caspase 3 activity.

It has been documented that caspase 3 activity is necessary for skeletal muscle regeneration, but how its activity is regulated is largely unknown. Our previous report shows that intracellular TMEM16A, a calcium activated chloride channel, significantly regulates caspase 3 activity in myoblasts during skeletal muscle development. By using a mouse line with satellite cell (SC)-specific deletion of TMEM16A, we examined the role of TMEM16A in regulating caspase 3 activity in SC (or SC-derived myoblast) as well as skeletal muscle regeneration. The mutant animals displayed apparently impaired regeneration capacity in adult muscle along with enhanced ER stress and elevated caspase 3 activity in Tmem16a-/- SC derived myoblasts. Blockade of either excessive ER stress or caspase 3 activity by small molecules significantly restored the inhibited myogenic differentiation of Tmem16a-/- SCs, indicating that excessive caspase 3 activity resulted from TMEM16A deletion contributes to the impaired muscle regeneration and the upstream regulator of caspase 3 was ER stress. Our results revealed an essential role of TMEM16A in satellite cell-mediated skeletal muscle regeneration by ensuring a moderate level of caspase 3 activity.

7753 Anoctamin 4 in the Area Postrema Regulates Glucose and Energy Homeostasis

Abstract Disclosure: L. Tu: None. Y. Xu: None. Located on the floor of the 4th ventricle within the dorsal surface of the medulla oblongata, the area postrema (AP) is a circumventricular organ where a proper blood-brain barrier is missing. Numerous studies reveal that neurons in the AP are implicated into suppression of food intake (e.g., glucagon-like peptide 1 (GLP-1)-mediated anorexia), but the role of AP neurons in whole-body glucose homeostasis is less investigated. Here we identified and fully characterized the physiological functions of anoctamin-4 (Ano4, a calcium activated chloride channel)1 in the AP. CRISPR-mediated deletion of Ano4 in the AP caused a lower body weight and reduced blood glucose, concurrent with an improved glucose tolerance and increased insulin sensitivity. Chemogenetic activation of Ano4-expressing neurons in the AP (APAno4) increased food intake and blood glucose, and did not induce conditioned flavor avoidance. Both Ano4 neurons and non-Ano4 neurons (i.e., neurons do not express Ano4) sent projections to the lateral parabrachial nucleus (LPBN). Optogenetic stimulation of APAno4 ◊ LPBN circuit promoted feeding behavior and increased blood glucose, whereas stimulation of APnon-Ano4 ◊ LPBN circuit inhibited food intake and did not influence glucose homeostasis. Finally, RNAscope studies reveal that 45.7% of APAno4 neurons are glutamatergic neurons, and 41.8% of them are GABAergic neurons. Furthermore, APAno4 neurons showed only a 2.6% overlap with Glp-1r-expressing neurons in the AP, but had a 60.8% co-localization with protein tyrosine phosphatase receptor δ2, which serves as orexigenic asprosin receptor. Together, our results indicate that Ano4 neurons in the AP are the first reported orexigenic neurons, and represent potential therapeutic targets for human diseases with glucose imbalance and abnormal feeding behavior. Reference: (1) Tu, L. et al. Anoctamin 4 channel currents activate glucose-inhibited neurons in the mouse ventromedial hypothalamus during hypoglycemia. J Clin Invest 133,14. (2023). (2) Mishra, I. et al. Protein tyrosine phosphatase receptor δ serves as the orexigenic asprosin receptor. Cell Metab 34, 549-563. (2022). Presentation: 6/2/2024

9207 Anoctamin 4 in the Area Postrema Regulates Glucose and Energy Homeostasis

Abstract Disclosure: L. Tu: None. Y. Xu: None. Located on the floor of the 4th ventricle within the dorsal surface of the medulla oblongata, the area postrema (AP) is a circumventricular organ where a proper blood-brain barrier is missing. Numerous studies reveal that neurons in the AP are implicated into suppression of food intake (e.g., glucagon-like peptide 1 (GLP-1)-mediated anorexia), but the role of AP neurons in whole-body glucose homeostasis is less investigated. Here we identified and fully characterized the physiological functions of anoctamin-4 (Ano4, a calcium activated chloride channel)1 in the AP. CRISPR-mediated deletion of Ano4 in the AP caused a lower body weight and reduced blood glucose, concurrent with an improved glucose tolerance and increased insulin sensitivity. Chemogenetic activation of Ano4-expressing neurons in the AP (APAno4) increased food intake and blood glucose, and did not induce conditioned flavor avoidance. Both Ano4 neurons and non-Ano4 neurons (i.e., neurons do not express Ano4) sent projections to the lateral parabrachial nucleus (LPBN). Optogenetic stimulation of APAno4 ◊ LPBN circuit promoted feeding behavior and increased blood glucose, whereas stimulation of APnon-Ano4 ◊ LPBN circuit inhibited food intake and did not influence glucose homeostasis. Finally, RNAscope studies reveal that 45.7% of APAno4 neurons are glutamatergic neurons, and 41.8% of them are GABAergic neurons. Furthermore, APAno4 neurons showed only a 2.6% overlap with Glp-1r-expressing neurons in the AP, but had a 60.8% co-localization with protein tyrosine phosphatase receptor δ2, which serves as orexigenic asprosin receptor. Together, our results indicate that Ano4 neurons in the AP are the first reported orexigenic neurons, and represent potential therapeutic targets for human diseases with glucose imbalance and abnormal feeding behavior. Reference: (1) Tu, L. et al. Anoctamin 4 channel currents activate glucose-inhibited neurons in the mouse ventromedial hypothalamus during hypoglycemia. J Clin Invest 133,14. (2023). (2) Mishra, I. et al. Protein tyrosine phosphatase receptor δ serves as the orexigenic asprosin receptor. Cell Metab 34, 549-563. (2022). Presentation: 6/2/2024

The epsilon toxin from Clostridium perfringens stimulates calcium-activated chloride channels, generating extracellular vesicles in Xenopus oocytes.

The epsilon toxin (Etx) from Clostridium perfringens has been identified as a potential trigger of multiple sclerosis, functioning as a pore-forming toxin that selectively targets cells expressing the plasma membrane (PM) myelin and lymphocyte protein (MAL). Previously, we observed that Etx induces the release of intracellular ATP in sensitive cell lines. Here, we aimed to re-examine the mechanism of action of the toxin and investigate the connection between pore formation and ATP release. We examined the impact of Etx on Xenopus laevis oocytes expressing human MAL. Extracellular ATP was assessed using the luciferin-luciferase reaction. Activation of calcium-activated chloride channels (CaCCs) and a decrease in the PM surface were recorded using the two-electrode voltage-clamp technique. To evaluate intracellular Ca2+ levels and scramblase activity, fluorescent dyes were employed. Extracellular vesicles were imaged using light and electron microscopy, while toxin oligomers were identified through western blots. Etx triggered intracellular Ca2+ mobilization in the Xenopus oocytes expressing hMAL, leading to the activation of CaCCs, ATP release, and a reduction in PM capacitance. The toxin induced the activation of scramblase and, thus, translocated phospholipids from the inner to the outer leaflet of the PM, exposing phosphatidylserine outside in Xenopus oocytes and in an Etx-sensitive cell line. Moreover, Etx caused the formation of extracellular vesicles, not derived from apoptotic bodies, through PM fission. These vesicles carried toxin heptamers and doughnut-like structures in the nanometer size range. In conclusion, ATP release was not directly attributed to the formation of pores in the PM, but to scramblase activity and the formation of extracellular vesicles.

BEST1 associated bestrophinopathies with angle closure and post-surgical malignant glaucoma

ABSTRACT Introduction Mutations in BEST1 gene have been linked to the development of refractory angle closure glaucoma (ACG). This study aims to delineate the clinical characteristics, genetic mutations, and disease progression in patients with autosomal recessive bestrophinopathy (ARB) and autosomal dominant Best vitelliform macular dystrophy (BVMD) who are presented with treatment-resistant ACG. Methods This retrospective analysis encompasses a comprehensive ophthalmic assessment, retinal imaging, and mutational profiling of six patients diagnosed with bestrophinopathy and concurrent ACG, with a particular emphasis on the risk of post-glaucoma filtration surgery malignant glaucoma (MG). Exome sequencing was conducted utilizing a next-generation sequencing (NGS) based gene panel. Results The cohort included five patients with ARB and one with BVMD, with a mean (±SD) age at ACG diagnosis of 35.1 ± 6.9 years. NGS analysis revealed homozygous BEST1 variants in four patients (ARB; cases 1–4) and a heterozygous BEST1 variant in one patient (BVMD; case 5). One patient (ARB; case 6), despite a recessive pedigree, showed a single heterozygous variant, suggesting the presence of an undetected heterozygous variant indicative of compound heterozygous autosomal recessive inheritance. A novel non-frameshift deletion (c.841_843delTTC; p.Phe281del) was identified in case 2. Surgical intervention was required due to uncontrolled glaucoma in all cases except case 4. All five cases that underwent glaucoma filtration surgery developed MG, which was effectively managed with combined iridozonulo-hyaloido-vitrectomy (IZHV) and pars plana vitrectomy (PPV). Cases 5 and 6, harboring a heterozygous pathogenic variant (c.241 G>A; p.Val81Met), experienced refractory MG and corneal decompensation necessitating multiple interventions. Conclusion Genomic analysis plays a pivotal role in the management of bestrophinopathies with ACG. Characterization of mutational types facilitates prognostication and enables timely interventions. IZHV with PPV emerges as a promising standalone or adjunctive procedure for the management of glaucoma among patients with BEST1 mutations and ACG.

Generation of Astrocyte-specific BEST1 Conditional Knockout Mouse with Reduced Tonic GABA Inhibition in the Brain.

Bestrophin-1 (BEST1) is a Ca2+-activated anion channel known for its role in astrocytes. Best1 is permeable to gliotransmitters, including GABA, to contribute to tonic GABA inhibition and modulate synaptic transmission in neighboring neurons. Despite the crucial functions of astrocytic BEST1, there is an absence of genetically engineered cell-type specific conditional mouse models addressing these roles. In this study, we developed an astrocyte-specific BEST1 conditional knock-out (BEST1 aKO) mouse line. Using the embryonic stem cell (ES cell) targeting method, we developed Best1 floxed mice (C57BL/6JCya-Best1em1flox/Cya), which have exon 3, 4, 5, and 6 of Best1 flanked by two loxP sites. By crossing with hGFAP-CreERT2 mice, we generated Best1 floxed/hGFAP-CreERT2 mice, which allowed for the tamoxifen-inducible deletion of Best1 under the human GFAP promoter. We characterized its features across various brain regions, including the striatum, hippocampal dentate gyrus (HpDG), and Parafascicular thalamic nucleus (Pf). Compared to the Cre-negative control, we observed significantly reduced BEST1 protein expression in immunohistochemistry (IHC) and tonic GABA inhibition in patch clamp recordings. The reduction in tonic GABA inhibition was 66.7% in the striatum, 46.4% in the HpDG, and 49.6% in the Pf. Our findings demonstrate that the BEST1 channel in astrocytes significantly contributes to tonic inhibition in the local brain areas. These mice will be valuable for future studies not only on tonic GABA release but also on tonic release of gliotransmitters mediated by astrocytic BEST1.

SARS-CoV-2 infection results in a unique lung proteome long after virus resolution in the hamster

Long COVID or post-acute sequelae of COVID-19 (PASC) remains an ongoing public health issue that causes impairment for those afflicted and diminishes their ability to contribute to society. To address the host response underpinning respiratory PASC, we used the Golden Syrian hamster model infected with ancestral SARS-CoV-2 and examined its lung proteome in a longitudinal experiment. We infected young 6-week old male and female hamsters with 105 TCID50 of virus via the intranasal route and sampled the lung at 1, 3, 5, and 31 days post infection (dpi). We compared the infected lung proteome to that of uninfected sex-matched controls. We found almost no differences in protein levels at 1 dpi, with hundreds at 3 dpi, and thousands at 5 dpi. Many overlapping differential protein levels and pathways were seen in both sexes at 3 and 5 dpi including the Coagulation and Complement cascades. Notably, we found differences between the sexes at 31 dpi which included many targets with decreased levels of protein in the males. We also noted an increase in 7 proteins in both sexes at 31 dpi including proteins responsible for airway mucosal layer integrity such as Mucin 5B and Calcium-activated chloride channel regulator 1. Longitudinally, 38 proteins were changed in levels across more than one timepoint in the males but only three proteins were in the females, Secretoglobin family 1 A member 1, Poly [ADP-ribose] polymerase, and Apolipoprotein D. Overall, we show that there are changes to the lung proteome at 31 dpi, a time when no SARS-CoV-2 remains, and that there are sex differences in that proteome after infection with the ancestral strain. We conclude that biological sex should be examined as a variable when testing medical countermeasures for PASC in the Golden Syrian hamster due to host differences between the sexes.

Analysis of the evolution and causes of groundwater chemistry after ecological water replenishment of the Jialu River, China

Ecological water replenishment is an important measure for conserving water sources and improving the water environment. To explore the evolution and causes of groundwater chemistry after ecological water replenishment in the Jialu River, this study utilized groundwater monitoring data from 2015 to 2019 following ecological water replenishment. Various methods, including Piper’s trilinear diagram, Gibbs diagram, principal component analysis, and ion ratio analysis, were employed for research purposes. The results indicate that (1) since the implementation of ecological water replenishment in the Jialu River, there has been a general downwards trend in total dissolved solids (TDS) in groundwater. The dominant cation in groundwater is Ca2+, whereas HCO3− is the dominant anion. The concentration of cations in groundwater has generally decreased, with noticeable reductions in SO42− and Cl− concentrations in the upper reaches of the recharge river contributing to improved groundwater quality. (2) A comparison with 2015 reveals a gradual transition at sampling points from chemical types such as HCO3-Ca·Mg and HCO3·Cl–Ca·Mg to an ecological water replenishment chemical type (HCO3-Ca).

Effect of TTYH3 on cholangiocarcinoma invasion, metastasis and lymph node metastasis through Wnt/β-catenin pathway.

57 Background: Cholangiocarcinoma is a malignant tumor originating from the bile duct epithelium. Metastasis is an important factor affecting the prognosis of cholangiocarcinoma. To explore the role and mechanism of calcium-activated chloride channel protein Tweety homolog 3 (TTYH3) in cholangiocarcinoma metastasis. Methods: TTYH3 was overexpressed and knocked down in cholangiocarcinoma cells, and in vitro experiments were performed to clarify the biological function of TTYH3 in cholangiocarcinoma. Experiments on xenograft tumor mice model have shown that TTYH3 promotes tumorigenesis of cholangiocarcinoma cells. Analysis of the relationship between TTYH3 expression and patient prognosis and lymph node metastasis in cholangiocarcinoma tissue specimens. Exosomes were extracted from bile of patients with cholangiocarcinoma and bile duct stones, and the expression of TTYH3 in exosomes was compared. TTYH3 overexpressed exosomes were used to treat endothelial cells, and their function and mechanism in promoting lymphangiogenesis were analyzed. Results: In vitro experiments confirmed that TTYH3 promoted the migration and invasion of cholangiocarcinoma cell line QBC939. In vivo experiments confirmed that TTYH3 promotes the tumorigenesis of cholangiocarcinoma cells. TTYH3 promotes epithelial-to-mesenchymal transition of cholangiocarcinoma cells through the Wnt/β-catenin signaling pathway. TTYH3 promotes cholangiocarcinoma cell self-expression through positive feedback. TTYH3 is highly expressed in cholangiocarcinoma tissues. Patients with high TTYH3 expression have poor prognosis and a high incidence of lymph node metastasis. The TTYH3 protein content of bile exosomes in patients with cholangiocarcinoma is increased, which promotes the invasion and metastasis of cholangiocarcinoma cells, while also promoting lymphangiogenesis and increased permeability. TTYH3 promotes the uptake of exosomes by lymphatic cells and promotes lymphangiogenesis by regulating the influx of calcium ions and chloride ions in lymphatic cells. Conclusions: TTYH3 promotes the invasion and metastasis of cholangiocarcinoma cells through the Wnt/β-catenin signaling pathway, and exosome TTYH3 promotes lymphangiogenesis and lymph node metastasis.

Hydrochemical Evolution Process and Mechanism of Groundwater in the Hutuo River Alluvial Fan, North China

Due to extensive groundwater exploitation, a groundwater funnel has persisted in the Hutuo River alluvial fan in Shijiazhuang since the 1980s, lasting nearly 40 years and significantly impacting the groundwater chemical characteristics. In this study, based on the groundwater level and chemistry data, the hydrochemical evolution processes and mechanisms of the groundwater during the 1980 groundwater funnel period and the post-2015 artificial governance period were investigated using traditional hydrogeochemical methods and inverse hydrogeochemical simulations. The results show the following: (1) The ion concentrations gradually increased along the groundwater flow path, where they displayed a pattern of lower levels in the northwest and higher levels in the southeast. From 1980 to 2021, the concentrations of major ions were increased. (2) In 1980s, the groundwater hydrochemical type predominantly exhibited HCO3—Ca. From 1980 to 2015, the hydrochemical types diversified into HCO3·Cl—Ca, HCO3—Ca·Mg, and HCO3·SO4—Ca types. Following the artificial governance, the groundwater level rise led to an increase in the concentrations of SO42− and Mg2+. Post-2015, the prevailing hydrochemical type changed to HCO3·SO4—Ca·Mg. (3) The changes in the groundwater level and ion concentrations were quantitatively strongly correlated and exhibited spatial similarity. (4) In the 1980s, the groundwater hydrochemical composition was primarily controlled by the dissolution of albite, dolomite, halite, and quartz; reverse cation exchange; and groundwater exploitation. Since 2015, the hydrochemical composition has mainly been influenced by the dissolution of albite, calcite, and quartz; positive cation exchange; river–groundwater mixing; and industrial activities, with increasing intensities of both water–rock interactions and human activities.

The effects of Cl− channel inhibitors and pyrethroid insecticides on calcium-activated chloride channels in neurons of Helicoverpa armigera

TMEM16A, a member of the Transmembrane protein 16 family, serves as the molecular basis for calcium activated chloride channels (CaCCs). We use RT-PCR to demonstrate the expression of TMEM16A in the neurons of Helicoverpa armigera, and record the CaCCs current of acute isolated neurons of H. armigera for the first time using patch clamp technology. In order to screen effective inhibitors of calcium-activated chloride channels, the inhibitory effects of four chloride channel inhibitors, CaCCinh-A01, NPPB, DIDS, and SITS, on CaCCs were compared. The inhibitory effects of the four inhibitors on the outward current of CaCCs were CaCCinh-A01 (10 μM, 56.31 %), NPPB (200 μM, 43.69 %), SITS (1 mM, 12.41 %) and DIDS (1 mM, 13.29 %). Among these inhibitors, CaCCinh-A01 demonstrated the highest efficacy as a blocker. To further explore whether calcium channel proteins can serve as potential targets of pyrethroids, we compared the effects of (type I) tefluthrin and (type II) deltamethrin on CaCCs. 10 μM and 100 μM tefluthrin can stimulate a large tail current in CaCCs, prolonging their deactivation time by 10.44 ms and 31.49 ms, and the V0.5 shifted in the hyperpolarization by 2–8 mV. Then, deltamethrin had no obvious effect on the deactivation and activation of CaCCs. Therefore, CaCCs of H. armigera can be used as a potential target of pyrethroids, but type I and type II pyrethroids have different effects on CaCCs.

Structural and theoretical basis for drug development targeting TMEM16A: Inhibition mechanism of tracheloside analogs

Ion channels play a crucial role in the electrophysiological activities of organisms. The calcium-activated chloride channel TMEM16A is involved in various physiological processes. Therefore, inhibitors of TMEM16A are used to treat diseases caused by TMEM16A dysfunction. However, the unclear inhibition mechanism hinders the progress of drug development. Based on our previous study, we found that the molecular structures of TMEM16A inhibitors tracheloside, matairesinoside and arctigenin are similar. In this study, we conducted a structure-based virtual screening of tracheloside analogs from the PubChem database. The six tracheloside analogs with the highest affinity to TMEM16A were selected, and their inhibitory effects were detected by fluorescence and electrophysiological experiments. Subsequently, the interaction between the tracheloside analogs and TMEM16A was investigated through molecular docking and site-directed mutagenesis. Based on the above results, the mechanism of inhibition of TMEM16A gated conformation by tracheloside analogs was proposed. These findings provide a structural and theoretical basis for drug development targeting TMEM16A.

Multimodal imaging analysis of autosomal recessive bestrophinopathy: Case series.

Autosomal recessive bestrophinopathy (ARB) is a subtype of bestrophinopathy caused by biallelic mutations of the BEST1 gene, which affect the retinal pigment epithelium (RPE). Studying RPE abnormalities through imaging is essential for understanding ARB. This case series involved the use of multimodal imaging techniques, namely autofluorescence (AF) imaging at 488 nm [short-wavelength AF] and 785 nm [near-infrared AF (NIR-AF)] and polarization-sensitive optical coherence tomography (PS-OCT), to investigate RPE changes in 2 siblings with ARB. Two Japanese siblings (Case 1: male, followed for 20-23 years; Case 2: female, followed for 13-17 years) carried compound heterozygous mutations of the BEST1 gene. Both siblings were diagnosed with ARB. Multimodal imaging techniques were used to evaluate RPE changes. Both siblings had funduscopic changes similar to those seen in the vitelliruptive stage of Best vitelliform macular dystrophy during the follow-up period. NIR-AF imaging showed hypo-AF of the entire macular lesion in both cases, and this hypo-AF remained stable over time. PS-OCT confirmed reduced RPE melanin content in these hypo-AF areas. Additionally, hyper-NIR-AF dots were observed within hypo-NIR-AF areas. Concomitant identification of focally thickened RPE melanin on PS-OCT imaging and hyper-AF on short-wavelength AF imaging at the sites containing hyper-NIR-AF dots indicated that the hyper-NIR-AF dots had originated from either stacked RPE cells or RPE dysmorphia. We confirmed RPE abnormalities in ARB, including diffuse RPE melanin damage in the macula alongside evidence of RPE activity-related changes. This case series demonstrates that multimodal imaging, particularly NIR-AF and PS-OCT, provides detailed insights into RPE alterations in ARB.

An Overview of Best Disease

The German ophthalmologist Friedrich Best named Best vitelliform macular dystrophy (BVD), sometimes referred to as Best disease, in 1905 when he discovered a family with a history of early-onset macular degeneration. A Swedish study assessed the frequency of BVMD to be 2 in 10,000, whereas a Danish examination found 1.5 in 100,000 cases. If a parent with the condition has a kid with an unaffected spouse, there is a 50% chance that the child will inherit the condition from the parent. The syndrome is caused by a mutation in the VMD2 or BEST1 gene found at chromosome 11q12-q13. It is yet unclear how bestrophinopathies pathophysiologically operate. An ionic imbalance in the RPE milieu, which BEST1 gene mutations can bring on, can lead to impaired RPE functions. The best sickness is in five phases. There is currently no recognized treatment for the best sickness. One treatment option for CNV is VEFG injections, either used alone or in conjunction with photodynamic therapy (PDT). Anti-vascular endothelial growth factor (Anti- VEGF) treatments can prevent or reduce the creation of new blood vessels. This can postpone the onset of blindness and slow down the rate at which they leak.

Long-Term PM2.5 Exposure and Upregulation of CLCA1 Expression in Nasal Epithelium from Youth with Asthma.

Little is known about long-term PM2.5 exposure and airway epithelial gene expression. To test for association between long-term PM2.5 exposure and nasal epithelial gene expression in youth with asthma. Transcriptome-wide association study (TWAS) of long-term PM2.5 in nasal epithelium from youth aged 6-20 years in the: 1) Epigenetic Variation and Childhood Asthma in Puerto Ricans study (EVA-PR, n=182); 2) Vitamin D Kids Asthma Study (VDKA, n=58); and 3) Stress and Treatment Response in Puerto Rican and African American Children with Asthma study (STAR, n=81). Satellite hybrid models were used to estimate PM2.5 exposure in the prior year at each participant's residence. Multivariable negative binomial regression was used for each TWAS, adjusting for age, sex, and other covariates. A meta-analysis of all TWAS results was then conducted using an inverse variance-weighted average approach. Most participants (~95%) in the meta-analysis of TWAS for PM2.5 exposure identified as Puerto Rican or Black. Long-term PM2.5 was associated with: 1) upregulated expression of CLCA1 (calcium-activated chloride channel regulator 1, false discovery rate-adjusted P [FDR-P]=0.008), SYCP2 (synaptonemal complex protein 2, FDR-P=0.01), and CYP2A6 (cytochrome p450 family 2 subfamily A member 6, FDR-P=0.02), and 2) downregulated expression of EDAR (ectodysplasin A receptor, FDR-P=0.01). In a meta-analysis, CLCA1 upregulation was associated with ≥1 positive allergen-specific IgE (FDR-P <0.001) and increased blood eosinophils (FDR-P <0.001) and total IgE (FDR-P <0.001). In a meta-analysis of TWASs in predominantly Puerto Rican and Black youth with asthma, long-term PM2.5 exposure was associated with upregulated airway epithelial CLCA1 expression, in turn linked to biomarkers of T2-high immunity.