RESUMO
SUMMARY: Calcium-activated chloride channel regulator 1 (CLCA1) is associated with cancer progression. The expression and immunologic function of CLCA1 in stomach adenocarcinoma (STAD) remain unclear. In this investigation, the expression of CLCA1 in STAD tissues and its involvement in the progression and immune response of STAD were examined using databases such as cBioPortal, TISIDB, and UALCAN. In order to validate the expression level of CLCA1 protein in gastric adenocarcinoma, thirty clinical tissue specimens were gathered for immunohistochemical staining. The findings indicated a downregulation of CLCA1 in STAD patients, which was correlated with race, age, cancer grade, Helicobacter pylori infection, and molecular subtype. Through the examination of survival analysis, it was identified that diminished levels of CLCA1 within gastric cancer cases were linked to decreased periods of post-progression survival (PPS), overall survival (OS), and first progression (FP) (P<0.05). The CLCA1 mutation rate was lower in STAD, but the survival rate was higher in the variant group. The correlation between the expression level of CLCA1 and the levels of immune infiltrating cells in STAD, as well as the immune activating molecules, immunosuppressive molecules, MHC molecules, chemokines, and their receptor molecules, was observed. Gene enrichment analysis revealed that CLCA1 may be involved in STAD progression through systemic lupus erythematosus (SLE), proteasome, cell cycle, pancreatic secretion, and PPAR signaling pathways. In summary, CLCA1 is anticipated to function as a prognostic marker for patients with STAD and is linked to the immunization of STAD.
El regulador 1 del canal de cloruro activado por calcio (CLCA1) está asociado con la progresión del cáncer. La expresión y la función inmunológica de CLCA1 en el adenocarcinoma de estómago (STAD) aún no están claras. En esta investigación, se examinó la expresión de CLCA1 en tejidos STAD y su participación en la progresión y respuesta inmune de STAD utilizando bases de datos como cBioPortal, TISIDB y UALCAN. Para validar el nivel de expresión de la proteína CLCA1 en el adenocarcinoma gástrico, se recolectaron treinta muestras de tejido clínico para tinción inmunohistoquímica. Los hallazgos indicaron una regulación negativa de CLCA1 en pacientes con STAD, que se correlacionó con la raza, la edad, el grado del cáncer, la infección por Helicobacter pylori y el subtipo molecular. Mediante el examen del análisis de supervivencia, se identificó que los niveles reducidos de CLCA1 en los casos de cáncer gástrico estaban relacionados con períodos reducidos de supervivencia posterior a la progresión (PPS), supervivencia general (OS) y primera progresión (FP) (P <0,05). La tasa de mutación CLCA1 fue menor en STAD, pero la tasa de supervivencia fue mayor en el grupo variante. Se observó la correlación entre el nivel de expresión de CLCA1 y los niveles de células inmunes infiltrantes en STAD, así como las moléculas activadoras inmunes, moléculas inmunosupresoras, moléculas MHC, quimiocinas y sus moléculas receptoras. El análisis de enriquecimiento genético reveló que CLCA1 puede estar involucrado en la progresión de STAD a través del lupus eritematoso sistémico (LES), el proteasoma, el ciclo celular, la secreción pancreática y las vías de señalización de PPAR. En resumen, se prevé que CLCA1 funcione como un marcador de pronóstico para pacientes con STAD y está vinculado a la inmunización de STAD.
Assuntos
Humanos , Neoplasias Gástricas/metabolismo , Adenocarcinoma/metabolismo , Canais de Cloreto/metabolismo , Prognóstico , Neoplasias Gástricas/imunologia , Imuno-Histoquímica , Adenocarcinoma/imunologia , Biomarcadores Tumorais , Análise de Sobrevida , Canais de Cloreto/genética , Canais de Cloreto/imunologia , Biologia Computacional , MutaçãoRESUMO
SUMMARY: We investigated Tweety Family Member 3 (TTYH3) level in lung adenocarcinoma (LUAD) and its relationship with immune infiltration in tumors by bioinformatics. Differential expressions of TTYH3 in lung cancer were analyzed with Oncomine, TIMER, GEO, UALCAN and HPA. Relationship of TTYH3 mRNA/protein levels with clinical parameters was analyzed by UALCAN. Co-expressed genes of TTYH3 in LUAD were analyzed using Cbioportal. Its relationship with LUAD prognosis was analyzed by Kaplan-Meier plotter. GO and KEGG analysis were performed. Correlation between TTYH3 and tumor immune infiltration were tested by TIMER, TISIDB and GEPIA. We found that TTYH3 was significantly increased in LUAD tissues. TTYH3 high expression was closely related to poor overall survival, post progression survival and first progression in LUAD patients. TTYH3 mRNA/protein levels were significantly associated with multiple pathways. Specifically, TTYH3 up-regulation was mostly related to biological regulation, metabolic process, protein blinding, extracellular matrix organization and pathways in cancer. Moreover, TTYH3 was positively associated with immune cell infiltration in LUAD. Finally, TTYH3 was highly expressed in LUAD as revealed by meta-analysis. TTYH3 is closely related to the prognosis of LUAD and immune cell infiltration, and it can be used as a prognostic biomarker for LUAD and immune infiltration.
Investigamos por bioinformática el nivel de Tweety Family Member 3 (TTYH3) con adenocarcinoma de pulmón (LUAD) y su relación con la infiltración inmune en tumores. Las expresiones diferenciales de TTYH3 en cáncer de pulmón se analizaron con Oncomine, TIMER, GEO, UALCAN y HPA. Con UALCAN se analizó la relación de los niveles de ARNm/proteína de TTYH3 con los parámetros clínicos. Los genes coexpresados de TTYH3 en LUAD se analizaron utilizando Cbioportal. Su relación con el pronóstico LUAD se analizó mediante plotter de Kaplan- Meier. Se realizaron análisis GO y KEGG. TIMER, TISIDB y GEPIA probaron la correlación entre TTYH3 y la infiltración inmune tumoral. Encontramos que TTYH3 aumentó significativamente en los tejidos LUAD. La alta expresión de TTYH3 estuvo estrechamente relacionada con una supervivencia general deficiente, supervivencia posterior a la progresión y primera progresión en pacientes con LUAD. Los niveles de ARNm/ proteína de TTYH3 se asociaron significativamente con múltiples vías. Específicamente, la regulación positiva de TTYH3 se relacionó principalmente con la regulación biológica, el proceso metabólico, el cegamiento de proteínas, la organización de la matriz extracelular y las vías en el cáncer. Además, TTYH3 se asoció positivamente con la infiltración de células inmunitarias en LUAD. Finalmente, TTYH3 se expresó altamente en LUAD como lo reveló el metanálisis. TTYH3 está estrechamente relacionado con el pronóstico de LUAD y la infiltración de células inmunitarias, y se puede utilizar como biomarcador pronóstico para LUAD y la infiltración de células inmunitarias.
Assuntos
Humanos , Canais de Cloreto/metabolismo , Adenocarcinoma de Pulmão/diagnóstico , Neoplasias Pulmonares/diagnóstico , Prognóstico , RNA Mensageiro , Linfócitos , Biomarcadores Tumorais , Canais de Cloreto/genética , Adenocarcinoma de Pulmão/imunologia , Adenocarcinoma de Pulmão/metabolismo , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/metabolismoRESUMO
Objective: To investigate the clinical presentation and genetic characteristics of malignant infantile osteopetrosis. Methods: This was a retrospective case study. Thirty-seven children with malignant infantile osteopetrosis admitted into Beijing Children's Hospital from January 2013 to September 2022 were enrolled in this study. According to the gene mutations, the patients were divided into the CLCN7 group and the TCIRG1 group. Clinical characteristics, laboratory tests, and prognosis were compared between two groups. Wilcoxon test or Fisher exact test were used in inter-group comparison. The survival rate was estimated with the Kaplan-Meier method and the Log-Rank test was used to compare the difference in survival between groups. Results: Among the 37 cases, there were 22 males and 15 females. The age of diagnosis was 0.5 (0.2, 1.0) year. There were 13 patients (35%) and 24 patients (65%) with mutations in CLCN7 and TCIRGI gene respectively. Patients in the CLCN7 group had an older age of diagnosis than those in the TCIRGI group (1.2 (0.4, 3.6) vs. 0.4 (0.2, 0.6) years, Z=-2.60, P=0.008). The levels of serum phosphorus (1.7 (1.3, 1.8) vs. 1.1 (0.8, 1.6) mmol/L, Z=-2.59, P=0.010), creatine kinase isoenzyme (CK-MB) (457 (143, 610) vs. 56 (37, 82) U/L, Z=-3.38, P=0.001) and the level of neutrophils (14.0 (9.9, 18.1) vs. 9.2 (6.7, 11.1) ×109/L, Z=-2.07, P=0.039) at diagnosis were higher in the CLCN7 group than that in the TCIRG1 group. However, the level of D-dimer in the CLCN7 group was lower than that in the TCIRGI group (2.7 (1.0, 3.1) vs. 6.3 (2.5, 9.7) μg/L, Z=2.83, P=0.005). After hematopoietic stem cell transplantation, there was no significant difference in 5-year overall survival rate between the two groups (92.3%±7.4% vs. 83.3%±7.6%, χ²=0.56, P=0.456). Conclusions: TCIRGI gene mutations are more common in children with osteopetrosis. Children with TCIRGI gene mutations have younger age, lower levels of phosphorus, CK-MB, and neutrophils and higher level of D-dimer at the onset. After hematopoietic stem cell transplantation, patients with CLCN7 or TCIRGI gene mutations have similar prognosis.
Assuntos
Criança , Masculino , Feminino , Humanos , Osteopetrose/terapia , Estudos Retrospectivos , Prognóstico , Genes Recessivos , Fósforo , Canais de Cloreto/genética , ATPases Vacuolares Próton-Translocadoras/genéticaRESUMO
OBJECTIVE@#To analyze the clinical phenotype and genetic variant in a child with Raynaud-Claes syndrome (RCS).@*METHODS@#A child who was diagnosed with RCS at the Children's Hospital Affiliated to Zhengzhou University for delayed language and motor development in August 2022 was selected as the study subject. Clinical data of the child were collected, and potential genetic variant was detected by next-generation sequencing and Sanger sequencing. The pathogenicity of the candidate variant was analyzed.@*RESULTS@#The child, a 4-year-and-4-month-old male, has manifested global developmental delay, speech disorders, special facial features and behavioral abnormalities. Genetic testing revealed that he has harbored a hemizygous c.1174C>T (p.Gln392Ter) variant of the CLCN4 gene, which was not detected in either of his parents. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was rated as pathogenic (PVS1+PS2+PM2_Supporting).@*CONCLUSION@#The c.1174C>T (p.Gln392Ter) variant of the CLCN4 gene probably underlay the PCS in this child. Above finding has expanded the mutational spectrum of the CLCN4 gene and enabled genetic counseling and prenatal diagnosis for his family.
Assuntos
Feminino , Humanos , Masculino , Gravidez , Pré-Escolar , Canais de Cloreto/genética , Aconselhamento Genético , Testes Genéticos , Genômica , Sequenciamento de Nucleotídeos em Larga Escala , MutaçãoRESUMO
La enfermedad de Dent es una tubulopatía recesiva ligada al cromosoma X caracterizada por proteinuria de bajo peso molecular (bpm), hipercalciuria, nefrocalcinosis o nefrolitiasis, disfunción tubular proximal e insuficiencia renal en la adultez. Las mujeres son portadoras y, en general, padecen una forma leve de la enfermedad. La progresión hacia la insuficiencia renal en estadio terminal se da entre los 30 y los 50 años de edad en el 30-80% de los varones afectados. A falta de un tratamiento dirigido al defecto molecular, en la actualidad, los pacientes con enfermedad de Dent reciben tratamientos complementarios orientados a prevenir la nefrolitiasis y la nefrocalcinosis. El caso que presentamos es el de un niño de 11 años con nefrocalcinosis y nefrolitiasis, en quien se detectó una nueva mutación en el gen CLCN5.
Dent's disease is a rare X-linked recessive tubulopathy characterized by low molecular weight (LMW) proteinuria, hypercalciuria, nephrolcalcinosis or nephrolithiasis, proximal tubular dysfunction and renal failure in adulthood. Females are carriers and usually mildly affected. Progression to endstage renal failure are at the 3rd-5th decades of life in 30-80% of affected males. In the absence of therapy targeting for the molecular defect, the current care of patients with Dent's disease is supportive, focusing on the prevention of nephrolithiasis and nephrocalcinosis. We present an 11-year-old child with nephrocalcinosis and nephrolithiasis caused by a new mutation at CLCN5 gene.
Assuntos
Humanos , Masculino , Criança , Canais de Cloreto/genética , Nefrolitíase/etiologia , Doença de Dent/genética , Nefrocalcinose/etiologia , Nefrolitíase/genética , Doença de Dent/fisiopatologia , Mutação , Nefrocalcinose/genéticaRESUMO
Gitelman's syndrome (GS) is caused by loss-of-function mutations in SLC12A3 and characterized by hypokalemic metabolic alkalosis, hypocalciuria, and hypomagnesemia. Long-term prognosis and the role of gene diagnosis in GS are still unclear. To investigate genotype-phenotype correlation in GS and Gitelman-like syndrome, we enrolled 34 patients who showed hypokalemic metabolic alkalosis without secondary causes. Mutation analysis of SLC12A3 and CLCNKB was performed. Thirty-one patients had mutations in SLC12A3, 5 patients in CLCNKB, and 2 patients in both genes. There was no significant difference between male and female in clinical manifestations at the time of presentation, except for early onset of symptoms in males and more profound hypokalemia in females. We identified 10 novel mutations in SLC12A3 and 4 in CLCNKB. Compared with those with CLCNKB mutations, patients with SLC12A3 mutations were characterized by more consistent hypocalciuria and hypomagnesemia. Patients with 2 mutant SLC12A3 alleles, compared with those with 1 mutant allele, did not have more severe clinical and laboratory findings except for lower plasma magnesium concentrations. Male and female patients did not differ in their requirement for electrolyte replacements. Two patients with concomitant SLC12A3 and CLCNKB mutations had early-onset severe symptoms and showed different response to treatment. Hypocalciuria and hypomagnesemia are useful markers in differentiation of GS and classical Bartter's syndrome. Gender, genotypes or the number of SLC12A3 mutant alleles cannot predict the severity of disease or response to treatment.
Assuntos
Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Alelos , Síndrome de Bartter/genética , Canais de Cloreto/genética , Análise Mutacional de DNA , Estudos de Associação Genética , Genótipo , Síndrome de Gitelman/genética , Hipopotassemia/etiologia , Fenótipo , Polimorfismo Genético , Membro 3 da Família 12 de Carreador de Soluto/genéticaRESUMO
Abstract Bartter syndrome comprises a group of rare autosomal-recessive salt-losing disorders with distinct phenotypes, but one unifying pathophysiology consisting of severe reductions of sodium reabsorption caused by mutations in five genes expressed in the thick ascending limb of Henle, coupled with increased urinary excretion of potassium and hydrogen, which leads to hypokalemic alkalosis. Bartter syndrome type IV, caused by loss-of-function mutations in barttin, a subunit of chloride channel CLC-Kb expressed in the kidney and inner ear, usually occurs in the antenatal-neonatal period. We report an unusual case of late onset presentation of Bartter syndrome IV and mild phenotype in a 20 years-old man who had hypokalemia, deafness, secondary hyperparathyroidism and erythrocytosis.
Resumo A síndrome de Bartter compreende um grupo raro de doenças autossômicas recessivas perdedoras de sal, decorrentes de mutações em genes expressos na porção ascendente espessa da alça de Henle, com fenótipos distintos, porém fisiopatogenia única, que consiste em redução severa da reabsorção de sódio, e aumento da excreção urinária de hidrogênio e potássio, levando à alcalose hipocalêmica. A síndrome de Bartter tipo IV, causada por mutações com perda de função da bartina, uma subunidade do canal de cloro CLC-Kb expressa no rim e ouvido interno, geralmente se apresenta nos períodos ante e neonatal. No presente relato, descreve-se um caso não usual de síndrome de Bartter tipo IV com apresentação tardia e fenótipo atenuado, diagnosticado por análise molecular, em um homem adulto de 20 anos que se apresentava com hipocalemia, surdez, hiperparatireoidismo secundário e eritrocitose.
Assuntos
Humanos , Masculino , Adulto Jovem , Síndrome de Bartter/complicações , Policitemia/complicações , Alcalose/metabolismo , Brasil , Síndrome de Bartter/genética , Canais de Cloreto/genética , Canais de Cloreto/metabolismo , Surdez/complicações , Hiperparatireoidismo Secundário/complicações , Hipopotassemia/complicações , Transtornos de Início Tardio/genética , Fenótipo , Potássio/urinaRESUMO
Background & objectives: Although clinical reports have described infantile malignant autosomal recessive osteopetrosis (ARO) in Indian patients, no published data are available about the genetic causes of ARO in this population. We investigated the main genetic causes of ARO in eight Indian patients with early postnatal onset and the typical severe clinical course including visual impairment and anaemia. Methods: Mutation screening in the genes CLCN7 and TCIRG1 was done on genomic DNA from 8 affected individuals (diagnosed on the basis of clinical and haematological parameters and characteristic radiological changes of increased bone density) and their parents. In one family, after detection of both mutations in the proband, targeted mutation analysis was also done in chorionic villus samples for prenatal diagnosis. Results: Six patients had mutations in TCIRG1 and two patients harboured mutations in CLCN7 gene. Three of the five different TCIRG1 mutations identified and both CLCN7 mutations were novel mutations. Except for the already known mutation p.Ile720del, all TCIRG1 mutations disrupt conserved splice consensus sequences or lead to premature stop codons. In contrast, both CLCN7 mutations only lead to missense changes of conserved amino acids. In a foetus harbouring TCIRG1 mutations osteopetrosis was visible radiologically at 23 wk of gestation. Interpretation & conclusions: That the CLCN7 mutations provoke a phenotype as severe as the one caused by TCIRG1 loss of function suggests the affected residues to be crucial for the function of the ClC-7 chloride channel or chloride/proton-exchanger. Our data also show that ARO can manifest as early as in the second trimester of pregnancy.
Assuntos
Canais de Cloreto/genética , Feminino , Genes Recessivos , Humanos , Índia , Lactente , Masculino , Mutação , Osteopetrose/genética , ATPases Vacuolares Próton-Translocadoras/genéticaRESUMO
Currents mediated by calcium-activated chloride channels (CaCCs), observed for the first time in Xenopus oocytes, have been recorded in many cells and tissues ranging from different types of neurons to epithelial and muscle cells. CaCCs play a role in the regulation of excitability in neurons including sensory receptors. In addition, they are crucial mediators of chloride movements in epithelial cells where their activity regulates electrolyte and fluid transport. The roles of CaCCs, particularly in epithelia, are briefly reviewed with emphasis on their function in secretory epithelia. The recent identification by three independent groups, using different strategies, of TMEM16A as the molecular counterpart of the CaCC is discussed. TMEM16A is part of a family that has 10 other members in mice. The discovery of the potential TMEM16 anion channel activity opens the way for the molecular investigation of the role of these anion channels in specific cells and in organ physiology and pathophysiology. The identification of TMEM16A protein as a CaCC chloride channel molecule represents a great triumph of scientific perseverance and ingenuity. The varied approaches used by the three independent research groups also augur well for the solidity of the discovery.
Assuntos
Animais , Humanos , Camundongos , Canais de Cloreto/metabolismo , Células Epiteliais , Proteínas de Membrana/metabolismo , Proteínas de Neoplasias/metabolismo , Proteínas de Xenopus/metabolismo , Canais de Cloreto/genética , Células Epiteliais/metabolismo , Mucosa Intestinal , Proteínas de Membrana/genética , Proteínas de Neoplasias/genética , Xenopus , Proteínas de Xenopus/genéticaRESUMO
Myotonia congenita (MC) is a form of nondystrophic myotonia caused by a mutation of CLCN1, which encodes human skeletal muscle chloride channel (CLC-1). We performed sequence analysis of all coding regions of CLCN1 in patients clinically diagnosed with MC, and identified 10 unrelated Korean patients harboring mutations. Detailed clinical analysis was performed in these patients to identify their clinical characteristics in relation to their genotypes. The CLCN1 mutational analyses revealed nine different point mutations. Of these, six (p.M128I, p.S189C, p.M373L, p.P480S, p.G523D, and p.M609K) were novel and could be unique among Koreans. While some features including predominant lower extremity involvement and normal to slightly elevated creatine kinase levels were consistently observed, general clinical features were highly variable in terms of age of onset, clinical severity, aggravating factors, and response to treatment. Our study is the first systematic study of MC in Korea, and shows its expanding clinical and genetic spectrums.
Assuntos
Adulto , Pré-Escolar , Humanos , Lactente , Masculino , Adulto Jovem , Sequência de Aminoácidos , Povo Asiático/genética , Sequência de Bases , Canais de Cloreto/genética , Análise Mutacional de DNA , Éxons , Coreia (Geográfico) , Dados de Sequência Molecular , Miotonia Congênita/genética , Mutação Puntual , Conformação ProteicaRESUMO
Myotonia congenita is a muscular disease characterized by myotonia, hypertrophy, and stiffness. It is inherited as either autosomal dominant or recessive known as Thomsen and Becker diseases, respectively. Here we confirm the clinical diagnosis of a family diagnosed with a myotonic condition many years ago and report a new mutation in the CLCN1 gene. The clinical diagnosis was established using ocular, cardiac, neurological and electrophysiological tests and the molecular diagnosis was done by PCR, SSCP and sequencing of the CLCN1 gene. The proband and the other affected individuals exhibited proximal and distal muscle weakness but no hypertrophy or muscular pain was found. The myotatic reflexes were lessened and sensibility was normal. Electrical and clinical myotonia was found only in the sufferers. Slit lamp and electrocardiogram tests were normal. Two affected probands presented diminution of the sensitive conduction velocities and prolonged sensory distal latencies. The clinical spectrum for this family is in agreement with a clinical diagnosis of Becker myotonia. This was confirmed by molecular diagnosis where a new disease-causing mutation (Q412P) was found in the family and absent in 200 unaffected chromosomes. No latent myotonia was found in this family; therefore the ability to cause this subclinical sign might be intrinsic to each mutation. Implications of the structure-function-genotype relationship for this and other mutations are discussed. Adequate clinical diagnosis of a neuromuscular disorder would allow focusing the molecular studies toward the confirmation of the initial diagnosis, leading to a proper clinical management, genetic counseling and improving in the quality of life of the patients and relatives.
La miotonía congénita es una enfermedad muscular caracterizada por miotonía, hipertrofia y rigidez. Se presenta con dos patrones de herencia, autosómica dominante en cuyo caso recibe el nombre de miotonía de Thomsen, o autosómica recesiva conocida como miotonía de Becker. En este trabajo se confirmó el diagnóstico clínico presuntivo hecho hace algunos años en una familia con una condición miotónica y se reporta una nueva mutación en el gen CLCN1. El diagnóstico clínico se estableció después de estudios oculares, cardíacos, neurológicos y electrofisiológicos. El diagnóstico molecular fue hecho mediante la PCR, SSCP y secuenciación del gen CLCN1. El caso índice y los otros individuos afectados exhibieron debilidad muscular proximal y distal, pero no se encontró hipertrofia ni dolor muscular. Los reflejos miotáticos estuvieron disminuidos y la sensibilidad fue normal. Se encontró miotonía clínica y eléctrica solo en los individuos afectados. Las pruebas de lámpara de hendidura y electrocardiograma resultaron normales. Dos individuos afectados presentaron disminución de las velocidades de conducción sensitiva y latencias distales sensoriales prolongadas. El cuadro clínico concuerda con la miotonía de Becker, lo cual se confirmó con el hallazgo de una mutación responsable de la enfermedad en el gen CLCN1 (Q412P), la cual se encontró en la familia y estuvo ausente en 200 cromosomas provenientes de la población general. No se encontró miotonía latente, por lo que probablemente la habilidad de causar este signo subclínico es intrínsica de cada mutación. Afinar el diagnóstico clínico diferencial de las enfermedades neuromusculares permitiría enfocar los estudios moleculares hacia la confirmación del diagnóstico inicial en forma eficiente, lo cual permitiría un manejo clínico y asesoramiento genético más adecuados y una mejora en la calidad de vida de los pacientes y sus familias.
Assuntos
Humanos , Masculino , Feminino , Criança , Adolescente , Adulto , Canais de Cloreto/genética , Miotonia Congênita/diagnóstico , Mutação/genética , Costa Rica , Enzimas de Restrição do DNA , Fenótipo , Linhagem , Marcadores Genéticos , Miotonia Congênita/genética , Polimorfismo Conformacional de Fita Simples , Reação em Cadeia da PolimeraseRESUMO
No abstract available.
Assuntos
Ratos , Animais , Ânions/metabolismo , Western Blotting , Canais de Cloreto/genética , Canais de Cloreto/análise , Expressão Gênica/fisiologia , Aparelho Lacrimal/citologia , Aparelho Lacrimal/química , RNA Mensageiro/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Glândula Submandibular/citologia , Glândula Submandibular/químicaRESUMO
In pancreatic acinar cells Ca(2+)-dependent secretagogues promote the fusion of zymogen granules (ZG) with the apical plasma membrane (PM) and exocytosis of digestive enzymes. In addition to exocytotic fusion complexes between SNARE proteins in the ZG membrane (ZGM) and the apical PM, enzyme secretion elicited by Ca(2+)-dependent secretagogues requires cytosolic Cl and K+ and is inhibited by blockers of Cl- and K+-channels. We have identified a Cl-conductance activated by ATP, and a K+-conductance (with properties similar to ATP-sensitive K+-channels), regulated by the granule matrix protein Zg-16p in the ZGM. Both conductances are inversely regulated by a 65-kD mdr1 gene product. We have also identified a novel Ca(2+)-activated anion conductance in ZGM, the Ca(2+)-sensitivity of which increases 50-fold when Cl is replaced by 1. This conductance is blocked by micromolar H2-DIDS or DTT, reminiscent of a family of epithelial Ca(2+)-activated Cl -channels (CaCC). Expression of a CaCC in exocrine pancreas has been confirmed by RT-PCR analysis, and by immunoblotting and immunogold labeling of ZG membranes. These data suggest that ion channels in the ZGM are essential elements in pancreatic exocytosis.