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1.
J Clin Invest ; 2024 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-39255033

RESUMO

The airway surface liquid (ASL) plays a crucial role in lung defense mechanisms, and its composition and volume are regulated by the airway epithelium. The cystic fibrosis transmembrane conductance regulator (CFTR) is abundantly expressed in a rare airway epithelial cell type called an ionocyte. Recently, we demonstrated that ionocytes can increase liquid absorption through apical CFTR and basolateral barttin/chloride channels, while airway secretory cells mediate liquid secretion through apical CFTR channels and basolateral NKCC1 transporters. Th2-driven (IL-4/IL-13) airway diseases, such as asthma, cause goblet cell metaplasia, accompanied by increased mucus production and airway secretions. In this study, we investigate the effect of IL-13 on chloride and liquid transport performed by ionocytes. IL-13 treatment of human airway epithelia was associated with reduced epithelial liquid absorption rates and increased ASL volume. Additionally, IL-13 treatment reduced the abundance of CFTR-positive ionocytes and increased the abundance of CFTR-positive secretory cells. Increasing ionocyte abundance attenuated liquid secretion caused by IL-13. Finally, CFTR-positive ionocytes were less common in asthma and COPD and associated with airflow obstruction. Our findings suggest that loss of CFTR in ionocytes contributes to the liquid secretion observed in IL-13-mediated airway diseases.

2.
Pharmacol Res Perspect ; 12(5): e70005, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39320019

RESUMO

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.


Assuntos
Trifosfato de Adenosina , Toxinas Bacterianas , Cálcio , Canais de Cloreto , Vesículas Extracelulares , Oócitos , Xenopus laevis , Animais , Oócitos/metabolismo , Oócitos/efeitos dos fármacos , Trifosfato de Adenosina/metabolismo , Cálcio/metabolismo , Vesículas Extracelulares/metabolismo , Vesículas Extracelulares/efeitos dos fármacos , Toxinas Bacterianas/metabolismo , Toxinas Bacterianas/toxicidade , Canais de Cloreto/metabolismo , Humanos , Membrana Celular/metabolismo , Membrana Celular/efeitos dos fármacos , Proteínas Proteolipídicas Associadas a Linfócitos e Mielina/metabolismo , Proteínas de Transferência de Fosfolipídeos/metabolismo , Feminino , Clostridium perfringens/metabolismo
3.
J Physiol ; 602(17): 4291-4307, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39106251

RESUMO

ClC-K/barttin channels are involved in the transepithelial transport of chloride in the kidney and inner ear. Their physiological role is crucial in humans because mutations in CLCNKB or BSND, encoding ClC-Kb and barttin, cause Bartter's syndrome types III and IV, respectively. In vitro experiments have shown that an amino acid change in a proline-tyrosine motif in the C-terminus of barttin stimulates ClC-K currents. The molecular mechanism of this enhancement and whether this potentiation has any in vivo relevance remains unknown. We performed electrophysiological and biochemical experiments in Xenopus oocytes and kidney cells co-expressing ClC-K and barttin constructs. We demonstrated that barttin possesses a YxxØ motif and, when mutated, increases ClC-K plasma membrane stability, resulting in larger currents. To address the impact of mutating this motif in kidney physiology, we generated a knock-in mouse. Comparing wild-type (WT) and knock-in mice under a standard diet, we could not observe any difference in ClC-K and barttin protein levels or localization, either in urinary or plasma parameters. However, under a high-sodium low-potassium diet, known to induce hyperplasia of distal convoluted tubules, knock-in mice exhibit reduced hyperplasia compared to WT mice. In summary, our in vitro and in vivo studies demonstrate that the previously identified PY motif is indeed an endocytic YxxØ motif in which mutations cause a gain of function of the channel. KEY POINTS: It is revealed by mutagenesis and functional experiments that a previously identified proline-tyrosine motif regulating ClC-K plasma membrane levels is indeed an endocytic YxxØ motif. Biochemical characterization of mutants in the YxxØ motif in Xenopus oocytes and human embryonic kidney cells indicates that mutants showed increased plasma membrane levels as a result of an increased stability, resulting in higher function of ClC-K channels. Mutation of this motif does not affect barttin protein expression and subcellular localization in vivo. Knock-in mice with a mutation in this motif, under conditions of a high-sodium low-potassium diet, exhibit less hyperplasia in the distal convoluted tubule than wild-type animals, indicating a gain of function of the channel in vivo.


Assuntos
Canais de Cloreto , Endocitose , Xenopus laevis , Animais , Canais de Cloreto/genética , Canais de Cloreto/metabolismo , Endocitose/fisiologia , Camundongos , Túbulos Renais Distais/metabolismo , Hiperplasia , Humanos , Feminino , Transportadores de Sulfato/genética , Transportadores de Sulfato/metabolismo , Camundongos Endogâmicos C57BL , Células HEK293 , Oócitos/metabolismo , Proteínas de Transporte de Ânions
4.
Biosci Microbiota Food Health ; 43(3): 234-240, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38966049

RESUMO

Constipation is strongly associated with the deterioration of quality of life (QOL), and patients with constipation desire clear spontaneous defecation without the feeling of incomplete evacuation, rather than improved defecation frequency. The use of common osmotic or stimulant laxatives has not been shown to lead to a satisfactory improvement of bowel movements. In addition, softening of stools by increasing their water content has been reported to increase the frequency of spontaneous defecation and improve hard stools, straining during defecation, and abdominal symptoms, such as abdominal bloating, thereby leading to improvement of QOL deterioration caused by constipation. Thus, the present study screened bacterial strains in vitro using intestinal epithelial T84 cells, aiming to identify one that activates chloride channels involved in water secretion into the intestinal tract. As a result, the conditioned medium of Bifidobacterium longum CLA8013 was found to induce ion transport. Also, this effect was suppressed by cystic fibrosis transmembrane conductance regulator (CFTR) (inh)-172, a CFTR chloride channel inhibitor. Furthermore, both live and heat-killed CLA8013 similarly induced ion transport, suggesting that bacterial cell components are responsible for the effect. In addition, the administration of heat-killed CLA8013 to loperamide-induced constipation rats resulted in an increase in fecal water content and promoted defecation. These results suggest that the active components in CLA8013 act on CFTR chloride channels in the intestinal tract, promote water secretion into the intestinal tract, and soften stools, thereby promoting bowel movements.

5.
Sci Rep ; 14(1): 17360, 2024 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-39075089

RESUMO

Prostaglandin E2 (PGE2) is a major contributor to inflammatory pain hyperalgesia, however, the extent to which it modulates the activity of nociceptive axons is incompletely understood. We developed and characterized a microfluidic cell culture model to investigate sensitisation of the axons of dorsal root ganglia neurons. We show that application of PGE2 to fluidically isolated axons leads to sensitisation of their responses to depolarising stimuli. Interestingly the application of PGE2 to the DRG axons elicited a direct and persistent spiking activity propagated to the soma. Both the persistent activity and the membrane depolarisation in the axons are abolished by the EP4 receptor inhibitor and a blocker of cAMP synthesis. Further investigated into the mechanisms of the spiking activity showed that the PGE2 evoked depolarisation was inhibited by Nav1.8 sodium channel blockers but was refractory to the application of TTX or zatebradine. Interestingly, the depolarisation of axons was blocked by blocking ANO1 channels with T16Ainh-A01. We further show that PGE2-elicited axonal responses are altered by the changes in chloride gradient within the axons following treatment with bumetanide a Na-K-2Cl cotransporter NKCC1 inhibitor, but not by VU01240551 an inhibitor of potassium-chloride transporter KCC2. Our data demonstrate a novel role for PGE2/EP4/cAMP pathway which culminates in a sustained depolarisation of sensory axons mediated by a chloride current through ANO1 channels. Therefore, using a microfluidic culture model, we provide evidence for a potential dual function of PGE2 in inflammatory pain: it sensitises depolarisation-evoked responses in nociceptive axons and directly triggers action potentials by activating ANO1 and Nav1.8 channels.


Assuntos
Anoctamina-1 , Axônios , Dinoprostona , Gânglios Espinais , Canal de Sódio Disparado por Voltagem NAV1.8 , Canal de Sódio Disparado por Voltagem NAV1.8/metabolismo , Animais , Dinoprostona/farmacologia , Dinoprostona/metabolismo , Axônios/metabolismo , Axônios/efeitos dos fármacos , Axônios/fisiologia , Gânglios Espinais/metabolismo , Gânglios Espinais/efeitos dos fármacos , Ratos , Anoctamina-1/metabolismo , Células Receptoras Sensoriais/metabolismo , Células Receptoras Sensoriais/efeitos dos fármacos , Potenciais de Ação/efeitos dos fármacos , Receptores de Prostaglandina E Subtipo EP4/metabolismo , Ratos Sprague-Dawley , Células Cultivadas , Membro 2 da Família 12 de Carreador de Soluto/metabolismo , AMP Cíclico/metabolismo
6.
J Clin Invest ; 134(16)2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38954478

RESUMO

Cystic fibrosis results from mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel, ultimately leading to diminished transepithelial anion secretion and mucociliary clearance. CFTR correctors are therapeutics that restore the folding/trafficking of mutated CFTR to the plasma membrane. The large-conductance calcium-activated potassium channel (BKCa, KCa1.1) is also critical for maintaining lung airway surface liquid (ASL) volume. Here, we show that the class 2 (C2) CFTR corrector VX-445 (elexacaftor) induces K+ secretion across WT and F508del CFTR primary human bronchial epithelial cells (HBEs), which was entirely inhibited by the BKCa antagonist paxilline. Similar results were observed with VX-121, a corrector under clinical evaluation. Whole-cell patch-clamp recordings verified that CFTR correctors potentiated BKCa activity from both primary HBEs and HEK cells stably expressing the α subunit (HEK-BK cells). Furthermore, excised patch-clamp recordings from HEK-BK cells verified direct action on the channel and demonstrated a significant increase in open probability. In mouse mesenteric artery, VX-445 induced a paxilline-sensitive vasorelaxation of preconstricted arteries. VX-445 also reduced firing frequency in primary rat hippocampal and cortical neurons. We raise the possibilities that C2 CFTR correctors gain additional clinical benefit by activation of BKCa in the lung yet may lead to adverse events through BKCa activation elsewhere.


Assuntos
Benzodioxóis , Regulador de Condutância Transmembrana em Fibrose Cística , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta , Humanos , Animais , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Camundongos , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta/metabolismo , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta/genética , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta/antagonistas & inibidores , Células HEK293 , Benzodioxóis/farmacologia , Ratos , Aminopiridinas/farmacologia , Fibrose Cística/metabolismo , Fibrose Cística/genética , Fibrose Cística/tratamento farmacológico , Fibrose Cística/patologia , Brônquios/metabolismo , Brônquios/efeitos dos fármacos , Células Epiteliais/metabolismo , Células Epiteliais/efeitos dos fármacos , Acetamidas , Indóis , Compostos de Tritil
7.
Acta Naturae ; 16(1): 40-47, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38698960

RESUMO

Proteins belonging to the anoctamin (ANO) family form calcium-activated chloride channels (CaCCs). The most unusual member of this family, ANO6 (TMEM16F), simultaneously exhibits the functions of calcium-dependent scramblase and the ion channel. ANO6 affects the plasma membrane dynamics and phosphatidylserine transport; it is also involved in programmed cell death. The properties of ANO6 channels remain the subject of debate. In this study, we investigated the effect of variations in the intracellular and extracellular concentrations of calcium ions on the electrophysiological properties of endogenous ANO6 channels by recording single ANO6 channels. It has been demonstrated that (1) a high calcium concentration in an extracellular solution increases the activity of endogenous ANO6 channels, (2) the permeability of endogenous ANO6 channels for chloride ions is independent of the extracellular concentration of calcium ions, (3) that an increase in the intracellular calcium concentration leads to the activation of endogenous ANO6 channels with double amplitude, and (4) that the kinetics of the channel depend on the plasma membrane potential rather than the intracellular concentration of calcium ions. Our findings give grounds for proposing new mechanisms for the regulation of the ANO6 channel activity by calcium ions both at the inner and outer sides of the membrane.

8.
Cell Calcium ; 120: 102889, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38677213

RESUMO

Chemical senses allow animals to detect and discriminate a vast array of molecules. The olfactory system is responsible of the detection of small volatile molecules, while water dissolved molecules are detected by taste buds in the oral cavity. Moreover, many animals respond to signaling molecules such as pheromones and other semiochemicals through the vomeronasal organ. The peripheral organs dedicated to chemical detection convert chemical signals into perceivable information through the employment of diverse receptor types and the activation of multiple ion channels. Two ion channels, TMEM16B, also known as anoctamin2 (ANO2) and TMEM16A, or anoctamin1 (ANO1), encoding for Ca2+-activated Cl¯ channels, have been recently described playing critical roles in various cell types. This review aims to discuss the main properties of TMEM16A and TMEM16B-mediated currents and their physiological roles in chemical senses. In olfactory sensory neurons, TMEM16B contributes to amplify the odorant response, to modulate firing, response kinetics and adaptation. TMEM16A and TMEM16B shape the pattern of action potentials in vomeronasal sensory neurons increasing the interspike interval. In type I taste bud cells, TMEM16A is activated during paracrine signaling mediated by ATP. This review aims to shed light on the regulation of diverse signaling mechanisms and neuronal excitability mediated by Ca-activated Cl¯ channels, hinting at potential new roles for TMEM16A and TMEM16B in the chemical senses.


Assuntos
Anoctaminas , Animais , Humanos , Anoctaminas/metabolismo , Anoctamina-1/metabolismo
9.
Biosci Rep ; 44(5)2024 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-38573803

RESUMO

Chloride is a key anion involved in cellular physiology by regulating its homeostasis and rheostatic processes. Changes in cellular Cl- concentration result in differential regulation of cellular functions such as transcription and translation, post-translation modifications, cell cycle and proliferation, cell volume, and pH levels. In intracellular compartments, Cl- modulates the function of lysosomes, mitochondria, endosomes, phagosomes, the nucleus, and the endoplasmic reticulum. In extracellular fluid (ECF), Cl- is present in blood/plasma and interstitial fluid compartments. A reduction in Cl- levels in ECF can result in cell volume contraction. Cl- is the key physiological anion and is a principal compensatory ion for the movement of the major cations such as Na+, K+, and Ca2+. Over the past 25 years, we have increased our understanding of cellular signaling mediated by Cl-, which has helped in understanding the molecular and metabolic changes observed in pathologies with altered Cl- levels. Here, we review the concentration of Cl- in various organs and cellular compartments, ion channels responsible for its transportation, and recent information on its physiological roles.


Assuntos
Cloretos , Humanos , Cloretos/metabolismo , Animais , Homeostase , Canais de Cloreto/metabolismo , Canais de Cloreto/genética , Transdução de Sinais , Líquido Extracelular/metabolismo , Transporte de Íons
10.
J Cell Mol Med ; 28(9): e18320, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38685684

RESUMO

Liver diseases include all types of viral hepatitis, alcoholic liver disease (ALD), nonalcoholic fatty liver disease (NAFLD), cirrhosis, liver failure (LF) and hepatocellular carcinoma (HCC). Liver disease is now one of the leading causes of disease and death worldwide, which compels us to better understand the mechanisms involved in the development of liver diseases. Anoctamin 1 (ANO1), a calcium-activated chloride channel (CaCC), plays an important role in epithelial cell secretion, proliferation and migration. ANO1 plays a key role in transcriptional regulation as well as in many signalling pathways. It is involved in the genesis, development, progression and/or metastasis of several tumours and other diseases including liver diseases. This paper reviews the role and molecular mechanisms of ANO1 in the development of various liver diseases, aiming to provide a reference for further research on the role of ANO1 in liver diseases and to contribute to the improvement of therapeutic strategies for liver diseases by regulating ANO1.


Assuntos
Anoctamina-1 , Hepatopatias , Humanos , Anoctamina-1/metabolismo , Anoctamina-1/genética , Hepatopatias/metabolismo , Hepatopatias/patologia , Hepatopatias/genética , Animais , Transdução de Sinais , Proteínas de Neoplasias/metabolismo , Proteínas de Neoplasias/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Regulação da Expressão Gênica
11.
bioRxiv ; 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38370666

RESUMO

Albendazole and ivermectin are the two most commonly co-administered anthelmintic drugs in mass-drug administration programs worldwide. Despite emerging resistance, we do not fully understand the mechanisms of resistance to these drugs nor the consequences of delivering them in combination. Albendazole resistance has primarily been attributed to variation in the drug target, a beta-tubulin gene. Ivermectin targets glutamate-gated chloride channel (GluCl) genes, but it is unknown whether these genes are involved in ivermectin resistance in nature. Using Caenorhabditis elegans, we defined the fitness costs associated with loss of the drug target genes singly or in combinations of the genes that encode GluCl subunits. We quantified the loss-of function effects on three traits: (i) multi-generational competitive fitness, (ii) fecundity, and (iii) development. In competitive fitness and development assays, we found that a deletion of the beta-tubulin gene ben-1 conferred albendazole resistance, but ivermectin resistance required loss of two GluCl genes (avr-14 and avr-15) or loss of three GluCl genes (avr-14, avr-15, and glc-1). The fecundity assays revealed that loss of ben-1 did not provide any fitness benefit in albendazole and that no GluCl deletion mutants were resistant to ivermectin. Next, we searched for evidence of multi-drug resistance across the three traits. Loss of ben-1 did not confer resistance to ivermectin, nor did loss of any single GluCl subunit or combination confer resistance to albendazole. Finally, we assessed the development of 124 C. elegans wild strains across six benzimidazoles and seven macrocyclic lactones to identify evidence of multi-drug resistance between the two drug classes and found a strong phenotypic correlation within a drug class but not across drug classes. Because each gene affects various aspects of nematode physiology, these results suggest that it is necessary to assess multiple fitness traits to evaluate how each gene contributes to anthelmintic resistance.

12.
Animals (Basel) ; 14(4)2024 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-38396552

RESUMO

Thirty-six healthy 21-day-old weaned ternary piglets (Duroc × Landrace × Yorkshire) were randomly divided into two treatments with 18 replicates per treatment and one pig per replicate. The control group was fed with a basal diet and the test group was fed with diets supplemented with 1 kg/t tea residue. The test period was 28 days. The results are as follows: The addition of tea residue in the diet had no significant effect on the growth performance of weaned piglets (p > 0.05), but it could significantly reduce the diarrhea rate of piglets from 1 to 7 days and 1 to 28 days (p < 0.05). Compared with the control group, the dietary supplementation of tea residue had no significant effect on nutrient apparent digestibility, plasma biochemical indexes and plasma immune indexes (p > 0.05) but increased the content of glutathione in plasma (p < 0.05). Tea residue had no significant effect on the morphology of the jejunum and ileum of piglets (p > 0.05), but it could significantly reduce the content of chloride ions in feces (p < 0.05). Compared with the basal diet group, there was no significant difference in the relative expression of TMEM16A and CFTR mRNA in the colon of weaned piglets (p > 0.05). The whole-cell patch clamp recording showed that the TMEM16A and CFTR ion channels could be activated by ionomycin and forskolin, respectively. However, when HT-29 cells transfected with TMEM16A and CFTR channels were treated with tea residue extract, it could significantly inhibit the chloride current of the TMEM16A and CFTR ion channels (p < 0.05).

13.
J Clin Invest ; 134(1)2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38165038

RESUMO

Myotonic dystrophy type 1 (DM1) involves misregulated alternative splicing for specific genes. We used exon or nucleotide deletion to mimic altered splicing of genes central to muscle excitation-contraction coupling in mice. Mice with forced skipping of exon 29 in the CaV1.1 calcium channel combined with loss of ClC-1 chloride channel function displayed markedly reduced lifespan, whereas other combinations of splicing mimics did not affect survival. The Ca2+/Cl- bi-channelopathy mice exhibited myotonia, weakness, and impairment of mobility and respiration. Chronic administration of the calcium channel blocker verapamil rescued survival and improved force generation, myotonia, and respiratory function. These results suggest that Ca2+/Cl- bi-channelopathy contributes to muscle impairment in DM1 and is potentially mitigated by common clinically available calcium channel blockers.


Assuntos
Canalopatias , Miotonia , Distrofia Miotônica , Camundongos , Animais , Distrofia Miotônica/tratamento farmacológico , Distrofia Miotônica/genética , Distrofia Miotônica/metabolismo , Cálcio/metabolismo , Cloretos/metabolismo , Miotonia/metabolismo , Verapamil/farmacologia , Verapamil/metabolismo , Canalopatias/genética , Canalopatias/metabolismo , Processamento Alternativo , Canais de Cloreto/genética , Canais de Cloreto/metabolismo , Músculo Esquelético/metabolismo
14.
Brain Commun ; 6(1): fcad273, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38173802

RESUMO

Mutations in CLCN2 are a rare cause of autosomal recessive leucoencephalopathy with ataxia and specific imaging abnormalities. Very few cases have been reported to date. Here, we describe the clinical and imaging phenotype of 12 additional CLCN2 patients and expand the known phenotypic spectrum of this disorder. Informed consent was obtained for all patients. Patients underwent either whole-exome sequencing or focused/panel-based sequencing to identify variants. Twelve patients with biallelic CLCN2 variants are described. This includes three novel likely pathogenic missense variants. All patients demonstrated typical MRI changes, including hyperintensity on T2-weighted images in the posterior limbs of the internal capsules, midbrain cerebral peduncles, middle cerebellar peduncles and cerebral white matter. Clinical features included a variable combination of ataxia, headache, spasticity, seizures and other symptoms with a broad range of age of onset. This report is now the largest case series of patients with CLCN2-related leucoencephalopathy and reinforces the finding that, although the imaging appearance is uniform, the phenotypic expression of this disorder is highly heterogeneous. Our findings expand the phenotypic spectrum of CLCN2-related leucoencephalopathy by adding prominent seizures, severe spastic paraplegia and developmental delay.

15.
J Clin Invest ; 134(2)2024 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-37962961

RESUMO

Cholera is a global health problem with no targeted therapies. The Ca2+-sensing receptor (CaSR) is a regulator of intestinal ion transport and a therapeutic target for diarrhea, and Ca2+ is considered its main agonist. We found that increasing extracellular Ca2+ had a minimal effect on forskolin-induced Cl- secretion in human intestinal epithelial T84 cells. However, extracellular Mg2+, an often-neglected CaSR agonist, suppressed forskolin-induced Cl- secretion in T84 cells by 65% at physiological levels seen in stool (10 mM). The effect of Mg2+ occurred via the CaSR/Gq signaling that led to cAMP hydrolysis. Mg2+ (10 mM) also suppressed Cl- secretion induced by cholera toxin, heat-stable E. coli enterotoxin, and vasoactive intestinal peptide by 50%. In mouse intestinal closed loops, luminal Mg2+ treatment (20 mM) inhibited cholera toxin-induced fluid accumulation by 40%. In a mouse intestinal perfusion model of cholera, addition of 10 mM Mg2+ to the perfusate reversed net fluid transport from secretion to absorption. These results suggest that Mg2+ is the key CaSR activator in mouse and human intestinal epithelia at physiological levels in stool. Since stool Mg2+ concentrations in patients with cholera are essentially zero, oral Mg2+ supplementation, alone or in an oral rehydration solution, could be a potential therapy for cholera and other cyclic nucleotide-mediated secretory diarrheas.


Assuntos
Cólera , Receptores de Detecção de Cálcio , Camundongos , Humanos , Animais , Receptores de Detecção de Cálcio/genética , Magnésio/farmacologia , Toxina da Cólera/farmacologia , Cálcio , Escherichia coli , Colforsina/farmacologia , Mucosa Intestinal , Diarreia/tratamento farmacológico , Células Epiteliais , Suplementos Nutricionais
16.
Handb Exp Pharmacol ; 283: 35-58, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-36811727

RESUMO

The molecular basis of chloride transport varies all along the nephron depending on the tubular segments especially in the apical entry of the cell. The major chloride exit pathway during reabsorption is provided by two kidney-specific ClC chloride channels ClC-Ka and ClC-Kb (encoded by CLCNKA and CLCNKB gene, respectively) corresponding to rodent ClC-K1 and ClC-K2 (encoded by Clcnk1 and Clcnk2). These channels function as dimers and their trafficking to the plasma membrane requires the ancillary protein Barttin (encoded by BSND gene). Genetic inactivating variants of the aforementioned genes lead to renal salt-losing nephropathies with or without deafness highlighting the crucial role of ClC-Ka, ClC-Kb, and Barttin in the renal and inner ear chloride handling. The purpose of this chapter is to summarize the latest knowledge on renal chloride structure peculiarity and to provide some insight on the functional expression on the segments of the nephrons and on the related pathological effects.


Assuntos
Cloretos , Rim , Cloretos/metabolismo , Membrana Celular/metabolismo , Canais de Cloreto/genética , Canais de Cloreto/metabolismo
17.
Biochem Biophys Res Commun ; 693: 149378, 2024 01 22.
Artigo em Inglês | MEDLINE | ID: mdl-38100999

RESUMO

Selective calcium chelator 1,2-Bis(2-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid (BAPTA) is a common tool to investigate calcium signaling. However, BAPTA expresses various effects on intracellular calcium signaling, which are not related to its ability to bind Ca2+. In patch clamp experiments, we investigated calcium chelation independent effects of BAPTA on endogenous calcium-activated chloride channels ANO6 (TMEM16F) in HEK293T cells. We have found that application of BAPTA to intracellular solution led to two distinct effects on channels properties. On the one hand, application of BAPTA acutely reduced amplitude of endogenous ANO6 channels induced by 10 µM Ca2+ in single channel recordings. On the other hand, BAPTA application by itself induced ANO6 channel activity in the absence of the intracellular calcium elevation. Open channel probability was enhanced by increasing the intracellular BAPTA concentration from 0.1 to 1 and 10 mM. Another calcium chelator EGTA did not demonstrate chelation independent effects on the ANO6 activity in the same conditions. Due to off-target effects BAPTA should be used with caution when studying calcium-activated ANO6 channels.


Assuntos
Canais de Cálcio , Cálcio , Humanos , Ácido Egtázico/farmacologia , Cálcio/metabolismo , Células HEK293 , Quelantes de Cálcio/farmacologia
18.
Curr Top Membr ; 92: 151-198, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38007267

RESUMO

The immune system is capable of identifying and eliminating cancer, a complicated illness marked by unchecked cellular proliferation. The significance of ion channels in the complex interaction between the immune system and cancer has been clarified by recent studies. Ion channels, which are proteins that control ion flow across cell membranes, have variety of physiological purposes, such as regulating immune cell activity and tumor development. Immune cell surfaces contain ion channels, which have been identified to control immune cell activation, motility, and effector activities. The regulation of immune responses against cancer cells has been linked to a number of ion channels, including potassium, calcium, and chloride channels. As an example, potassium channels are essential for regulating T cell activation and proliferation, which are vital for anti-tumor immunity. Calcium channels play a crucial role when immune cells produce cytotoxic chemicals in order to eliminate cancer cells. Chloride channels also affect immune cell infiltration and invasion into malignancies. Additionally, tumor cells' own expressed ion channels have an impact on their behavior and in the interaction with the immune system. The proliferation, resistance to apoptosis, and immune evasion of cancer cells may all be impacted by changes in ion channel expression and function. Ion channels may also affect the tumor microenvironment by controlling angiogenesis, inflammatory responses, and immune cell infiltration. Ion channel function in the interaction between the immune system and cancer has important implications for cancer treatment. A possible method to improve anti-tumor immune responses and stop tumor development is to target certain ion channels. Small compounds and antibodies are among the ion channel modulators under investigation as possible immunotherapeutics. The complex interaction between ion channels, the immune system, and cancer highlights the significance of these channels for tumor immunity. The development of novel therapeutic strategies for the treatment of cancer will be made possible by unraveling the processes by which ion channels control immune responses and tumor activity. Hence, the main driving idea of the present chapter is trying to understand the possible function of ion channels in the complex crosstalk between cancer and immunoresponse. To this aim, after giving a brief journey of ion channels throughout the history, a classification of the main ion channels involved in cancer disease will be discussed. Finally, the last paragraph will focus on more recently advancements in the use of biomaterials as therapeutic strategy for cancer treatment. The hope is that future research will take advantage of the promising combination of ion channels, immunomodulation and biomaterials filed to provide better solutions in the treatment of cancer disease.


Assuntos
Neoplasias , Humanos , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Canais Iônicos/metabolismo , Canais de Cloreto/uso terapêutico , Sistema Imunitário/metabolismo , Materiais Biocompatíveis/uso terapêutico , Microambiente Tumoral
19.
Front Pharmacol ; 14: 1283623, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37942486

RESUMO

Despite improvements in treatment, lung cancer is still a major health problem worldwide. Among lung cancer subtypes, the most frequent is represented by adenocarcinoma (belonging to the Non-Small Cell Lung Cancer class) although the most challenging and harder to treat is represented by Small Cell Lung Cancer, that occurs at lower frequency but has the worst prognosis. For these reasons, the standard of care for these patients is represented by a combination of surgery, radiation therapy and chemotherapy. In this view, searching for novel biomarkers that might help both in diagnosis and therapy is mandatory. In the last 30 years it was demonstrated that different families of ion channels are overexpressed in both lung cancer cell lines and primary tumours. The altered ion channel profile may be advantageous for diagnostic and therapeutic purposes since most of them are localised on the plasma membrane thus their detection is quite easy, as well as their block with specific drugs and antibodies. This review focuses on ion channels (Potassium, Sodium, Calcium, Chloride, Anion and Nicotinic Acetylcholine receptors) in lung cancer (both Non-Small Cell Lung Cancer and Small Cell Lung Cancer) and recapitulate the up-to-date knowledge about their role and clinical relevance for a potential use in the clinical setting, for lung cancer diagnosis and therapy.

20.
Cell Rep ; 42(9): 113075, 2023 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-37691148

RESUMO

The capacity of animals to respond to hazardous stimuli in their surroundings is crucial for their survival. In mammals, complex evaluations of the environment require large numbers and different subtypes of neurons. The nematode C. elegans avoids hazardous chemicals they encounter by reversing their direction of movement. How does the worms' compact nervous system process the spatial information and direct motion change? We show here that a single interneuron, AVA, receives glutamatergic excitatory and inhibitory signals from head and tail sensory neurons, respectively. AVA integrates the spatially distinct and opposing cues, whose output instructs the animal's behavioral decision. We further find that the differential activation of AVA stems from distinct localization of inhibitory and excitatory glutamate-gated receptors along AVA's process and from different threshold sensitivities of the sensory neurons. Our results thus uncover a cellular mechanism that mediates spatial computation of nociceptive cues for efficient decision-making in C. elegans.

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