15,423 research outputs found

    Severe phenotype in an apparent homozygosity caused by a large deletion in the CFTR gene: a case report

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    BACKGROUND: Over 1900 mutations have been identified in the cystic fibrosis conductance transmembrane regulator gene, including single nucleotide substitutions, insertions, and deletions. Unidentified mutations may still lie in introns or in regulatory regions, which are not routinely investigated, or in large genomic deletions, which are not revealed by conventional molecular analysis. The apparent homozygosity for a rare, cystic fibrosis conductance transmembrane regulator mutation screened by standard molecular analysis should be further investigated to confirm if the mutation is in fact homozygous. We describe a patient presenting with an apparent homozygous S4X mutation. CASE PRESENTATION: A 13-year-old female patient of African descent with clinical symptoms of classic cystic fibrosis and a positive sweat test (97¬†mEq/L, diagnosed at age 3¬†years) presented with pancreatic insufficiency and severe pulmonary symptoms (initial lung colonization with Pseudomonas aeruginosa at age 4¬†years; forced vital capacity: 69%; forced expiratory volume: 51%; 2011). Furthermore, she developed severe acute lung disease and recurrent episodes of dehydration requiring hospitalization. The girl carried the CFTR mutation S4X in apparent homozygosity. However, further analysis revealed a large deletion in the second allele that included the region of the mutation. The deletion that we describe includes nucleotides 120‚Äď142, which correspond to a loss of 23 nucleotides that abolishes the normal translation initiation codon. CONCLUSION: This study reiterates the view that large, cystic fibrosis conductance transmembrane regulator deletions are an important cause of severe cystic fibrosis and emphasizes the importance of including large deletions/duplications in cystic fibrosis conductance transmembrane regulator diagnostic tests

    New era of cystic fibrosis: full mutational analysis and personalized therapy

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    Despite its apparently simple genetics, cystic fibrosis (CF) is a rather complex genetic disease. A lot of variability in the steps of the path from the cystic fibrosis transmembrane conductance regulator (CFTR ) gene to the clinical manifestations originates an uncertain genotype - phenotype relationship. A major determinant of this uncertainty is the incomplete knowledge of the CFTR mutated genotypes, due to the high number of CFTR mutations and to the higher number of their combinations in trans and in cis. Also the very limited knowledge of functional effects of CFTR mutated alleles severely impairs our diagnostic and prognostic ability. The final phenotypic modulation exerted by CFTR modifier genes and interactome further complicates the framework. The next generation sequencing approach is a rapid, lowcost and high-throughput tool that allows a near complete structural characterization of CFTR mutated genotypes, as well as of genotypes of several other genes cooperating to the final CF clinical manifestations. This powerful method perfectly complements the new personalized therapeutic approach for CF. Drugs active on specific CFTR mutational classes are already available for CF patients or are in phase 3 trials. A complete genetic characterization has been becoming crucial for a correct personalized therapy. However, the need of a functional classification of each CFTR mutation potently arises. Future big efforts towards an ever more detailed knowledge of both structural and functional CFTR defects, coupled to parallel personalized therapeutic interventions decisive for CF cure can be foreseen

    Lack of correlation between pulmonary disease and cystic fibrosis transmembrane conductance regulator dysfunction in cystic fibrosis: a case report

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    Abstract Introduction Mutations in both alleles of the cystic fibrosis transmembrane conductance regulator gene result in the disease cystic fibrosis, which usually manifests as chronic sinopulmonary disease, pancreatic insufficiency, elevated sodium chloride loss in sweat, infertility among men due to agenesis of the vas deferens and other symptoms including liver disease. Case presentation We describe a pair of African-American brothers, aged 21 and 27, with cystic fibrosis. They were homozygous for a rare frameshift mutation in the cystic fibrosis transmembrane conductance regulator 3791delC, which would be expected to cause significant morbidity. Although 80% of cystic fibrosis patients are colonized with Pseudomonas aeruginosa by eight years of age, the older brother had no serum opsonic antibody titer to P. aeruginosa by age 13 and therefore would have failed to mount an effective antibody response to the alginate (mucoid polysaccharide) capsule of P. aeruginosa. He was not colonized with P. aeruginosa until 24 years of age. Similarly, the younger brother was not colonized with P. aeruginosa until age 20 and had no significant lung disease. Conclusion Despite a prevailing idea in cystic fibrosis research that the amount of functional cystic fibrosis transmembrane conductance regulator predicts clinical status, our results indicated that respiratory disease severity in cystic fibrosis exhibits phenotypic heterogeneity. If this heterogeneity is, in part, genetic, it is most likely derived from genes outside the cystic fibrosis transmembrane conductance regulator locus

    Consequences of cystic fibrosis transmembrane regulator mutations on inflammatory cells

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    Recent studies in cystic fibrosis (CF) transmembrane regulator (CFTR) mutations and function have shed light on its involvement in disease progression. The extent of cell and tissue distribution of CFTR facilitates systemic dysfunction of ion transport in patients carrying a mutation in CFTR, however, its incidences as cofounding risk factor to develop other diseases is not well studied. In this review we differentiate the dysfunctions driven by CFTR mutations in cell of the immune system and their role in CF progression and examine the types of medical treatments available to patients up to date.Fil: Grumelli, Sandra. Universidad Católica de Córdoba; ArgentinaFil: Islan, German Abel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Fermentaciones Industriales. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Fermentaciones Industriales; ArgentinaFil: Castro, Guillermo Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Fermentaciones Industriales. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Fermentaciones Industriales; Argentin

    Mechanisms of endothelial cell dysfunction in cystic fibrosis

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    Although cystic fibrosis (CF) patients exhibit signs of endothelial perturbation, the functions of the cystic fibrosis conductance regulator (CFTR) in vascular endothelial cells (EC) are poorly defined. We sought to uncover biological activities of endothelial CFTR, relevant for vascular homeostasis and inflammation. We examined cells from human umbilical cords (HUVEC) and pulmonary artery isolated from non-cystic fibrosis (PAEC) and CF human lungs (CF-PAEC), under static conditions or physiological shear. CFTR activity, clearly detected in HUVEC and PAEC, was markedly reduced in CF-PAEC. CFTR blockade increased endothelial permeability to macromolecules and reduced trans‚ÄĎendothelial electrical resistance (TEER). Consistent with this, CF-PAEC displayed lower TEER compared to PAEC. Under shear, CFTR blockade reduced VE-cadherin and p120 catenin membrane expression and triggered the formation of paxillin- and vinculin-enriched membrane blebs that evolved in shrinking of the cell body and disruption of cell-cell contacts. These changes were accompanied by enhanced release of microvesicles, which displayed reduced capability to stimulate proliferation in recipient EC. CFTR blockade also suppressed insulin-induced NO generation by EC, likely by inhibiting eNOS and AKT phosphorylation, whereas it enhanced IL-8 release. Remarkably, phosphodiesterase inhibitors in combination with a ő≤2 adrenergic receptor agonist corrected functional and morphological changes triggered by CFTR dysfunction in EC. Our results uncover regulatory functions of CFTR in EC, suggesting a physiological role of CFTR in the maintenance EC homeostasis and its involvement in pathogenetic aspects of CF. Moreover, our findings open avenues for novel pharmacology to control endothelial dysfunction and its consequences in CF

    Essential role of CFTR in PKA-dependent phosphorylation, alkalinization, and hyperpolarization during human dperm capacitation

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    Mammalian sperm require to spend a limited period of time in the female reproductive tract to become competent to fertilize in a process called capacitation. It is well established that HCO3 ‚ąí is essential for capacitation because it activates the atypical soluble adenylate cyclase ADCY10 leading to cAMP production, and promotes alkalinization of cytoplasm, and membrane hyperpolarization. However, how HCO3 ‚ąí is transported into the sperm is not well understood. There is evidence that CFTR activity is involved in the human sperm capacitation but how this channel is integrated in the complex signaling cascades associated with this process remains largely unknown. In the present work, we have analyzed the extent to which CFTR regulates different events in human sperm capacitation. We observed that inhibition of CFTR affects HCO3 ‚ąí-entrance dependent events resulting in lower PKA activity. CFTR inhibition also affected cAMP/PKA-downstream events such as the increase in tyrosine phosphorylation, hyperactivated motility, and acrosome reaction. In addition, we demonstrated for the first time, that CFTR and PKA activity are essential for the regulation of intracellular pH, and membrane potential in human sperm. Addition of permeable cAMP partially recovered all the PKA-dependent events altered in the presence of inh-172 which is consistent with a role of CFTR upstream of PKA activation.Fil: Puga Molina, Lis del Carmen. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Instituto de Biolog√≠a y Medicina Experimental. Fundaci√≥n de Instituto de Biolog√≠a y Medicina Experimental. Instituto de Biolog√≠a y Medicina Experimental; ArgentinaFil: Pinto, Nicol√°s Alejandro. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Instituto de Biolog√≠a y Medicina Experimental. Fundaci√≥n de Instituto de Biolog√≠a y Medicina Experimental. Instituto de Biolog√≠a y Medicina Experimental; ArgentinaFil: Torres Rodr√≠guez, Paulina. Universidad Nacional Aut√≥noma de M√©xico; M√©xicoFil: Romarowski, Ana. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Instituto de Biolog√≠a y Medicina Experimental. Fundaci√≥n de Instituto de Biolog√≠a y Medicina Experimental. Instituto de Biolog√≠a y Medicina Experimental; ArgentinaFil: Vicens Sanchez, Alberto. Universidad Nacional Aut√≥noma de M√©xico; M√©xicoFil: Visconti, Pablo E.. University of Massachussets; Estados UnidosFil: Darszon, Alberto. Universidad Nacional Aut√≥noma de M√©xico; M√©xicoFil: Trevi√Īo, Claudia L.. Universidad Nacional Aut√≥noma de M√©xico; M√©xicoFil: Buffone, Mariano Gabriel. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Instituto de Biolog√≠a y Medicina Experimental. Fundaci√≥n de Instituto de Biolog√≠a y Medicina Experimental. Instituto de Biolog√≠a y Medicina Experimental; Argentin

    Mechanisms of CFTR Functional Variants That Impair Regulated Bicarbonate Permeation and Increase Risk for Pancreatitis but Not for Cystic Fibrosis

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    CFTR is a dynamically regulated anion channel. Intracellular WNK1-SPAK activation causes CFTR to change permeability and conductance characteristics from a chloride-preferring to bicarbonate-preferring channel through unknown mechanisms. Two severe CFTR mutations (CFTRsev) cause complete loss of CFTR function and result in cystic fibrosis (CF), a severe genetic disorder affecting sweat glands, nasal sinuses, lungs, pancreas, liver, intestines, and male reproductive system. We hypothesize that those CFTR mutations that disrupt the WNK1-SPAK activation mechanisms cause a selective, bicarbonate defect in channel function (CFTRBD) affecting organs that utilize CFTR for bicarbonate secretion (e.g. the pancreas, nasal sinus, vas deferens) but do not cause typical CF. To understand the structural and functional requirements of the CFTR bicarbonate-preferring channel, we (a) screened 984 well-phenotyped pancreatitis cases for candidate CFTRBD mutations from among 81 previously described CFTR variants; (b) conducted electrophysiology studies on clones of variants found in pancreatitis but not CF; (c) computationally constructed a new, complete structural model of CFTR for molecular dynamics simulation of wild-type and mutant variants; and (d) tested the newly defined CFTRBD variants for disease in non-pancreas organs utilizing CFTR for bicarbonate secretion. Nine variants (CFTR R74Q, R75Q, R117H, R170H, L967S, L997F, D1152H, S1235R, and D1270N) not associated with typical CF were associated with pancreatitis (OR 1.5, p = 0.002). Clones expressed in HEK 293T cells had normal chloride but not bicarbonate permeability and conductance with WNK1-SPAK activation. Molecular dynamics simulations suggest physical restriction of the CFTR channel and altered dynamic channel regulation. Comparing pancreatitis patients and controls, CFTRBD increased risk for rhinosinusitis (OR 2.3, p<0.005) and male infertility (OR 395, p<<0.0001). WNK1-SPAK pathway-activated increases in CFTR bicarbonate permeability are altered by CFTRBD variants through multiple mechanisms. CFTRBD variants are associated with clinically significant disorders of the pancreas, sinuses, and male reproductive system.Fil: LaRusch, Jessica. Univeristy of Pittsburgh. School of Medicine; Estados UnidosFil: Jung, Jinsei. Yonsei University College of Medicine; Corea del SurFil: General, Ignacio. University of Pittsburgh; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lewis, Michele D.. Mayo Clinic. Division of Gastroenterology and Hepatology; Estados UnidosFil: Park, Hyun Woo. Yonsei University College of Medicine; Corea del SurFil: Brand, Randall E.. Univeristy of Pittsburgh. School of Medicine; Estados UnidosFil: Gelrud, Andres. Univeristy of Pittsburgh. School of Medicine; Estados UnidosFil: Anderson, Michelle A.. University of Michigan; Estados UnidosFil: Banks, Peter A.. Brigham and Women’s Hospital. Division of Gastroenterology; Estados UnidosFil: Conwell, Darwin. Brigham and Women’s Hospital. Division of Gastroenterology; Estados UnidosFil: Lawrence, Christopher. Medical University of South Carolina; Estados UnidosFil: Romagnuolo, Joseph. Medical University of South Carolina; Estados UnidosFil: Baillie, John. University of Duke; Estados UnidosFil: Alkaade, Samer. St. Louis University. School of Medicine; Estados UnidosFil: Cote, Gregory. Indiana University; Estados UnidosFil: Gardner, Timothy B.. Dartmouth-Hitchcock Medical Center; Estados UnidosFil: Amann, Stephen T.. North Mississippi Medical Center; Estados UnidosFil: Slivka, Adam. Univeristy of Pittsburgh. School of Medicine; Estados UnidosFil: Sandhu, Bimaljit. Virginia Commonwealth University Medical Center; Estados UnidosFil: Aloe, Amy. Univeristy of Pittsburgh. School of Medicine; Estados UnidosFil: Kienholz, Michelle L.. Univeristy of Pittsburgh. School of Medicine; Estados UnidosFil: Yadav, Dhiraj. Univeristy of Pittsburgh. School of Medicine; Estados UnidosFil: Barmada, M. Michael. Univeristy of Pittsburgh. School of Medicine; Estados UnidosFil: Bahar, Ivet. Univeristy of Pittsburgh. School of Medicine; Estados UnidosFil: Lee, Min Goo. Yonsei University College of Medicine; Corea del SurFil: Whitcomb, David C.. Univeristy of Pittsburgh. School of Medicine; Estados UnidosFil: North American Pancreatitis Study Group. No especifica
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