Hereditary pancreatitis (HP) is an autosomal dominant inherited disease characterized by recurrent episodes of pancreatitis often beginning in childhood, a family history of at least 2 other affected members, and the absence of known etiologic factors. The discovery of mutations in cationic trypsinogen gene (PRSS1) in HP not only provided insights into the molecular mechanisms of pancreatitis, but also opened a new era in the field of chronic pancreatitis. The detection of mutations in serine protease inhibitor, Kazal type 1 (SPINK1) and CFTR in patients with hereditary or idiopathic chronic pancreatitis has placed the emphasis on the importance of genetic mutations in pancreatitis. Because the estimated cumulative risk of pancreatic cancer developement in hereditary pancreatitis is nearly 40%, screening tests are important in selected cases. There are no specific medical therapies recommended in patients with HP. Registration of patients with Nationwise Registries is essential if management strategies are to be improved and genetic research to be continued.
Carrier Proteins/genetics ; Cystic Fibrosis Transmembrane Conductance Regulator/genetics ; Humans ; Mutation ; Pancreatitis/*genetics ; Trypsinogen/genetics

Thanks to recent progress in availability of molecular and functional techniques it became possible to search for the basic molecular and cellular processes that mediate and control HCO3- and fluid secretion by the pancreatic duct. The coordinated action of various transporters on the luminal and basolateral membranes of polarized epithelial cells mediates the transepithelial HCO3- transport, which involves HCO3- absorption in the resting state and HCO3- secretion in the stimulated state. The overall process of HCO3- secretion can be divided into two steps. First, HCO3- in the blood enters the ductal epithelial cells across the basolateral membrane either by simple diffusion in the forms of CO2 and H2O or by the action of an Na+-coupled transporter, a Na+-HCO3- cotranporter (NBC) identified as pNBC1. Subsequently, the cells secrete HCO3- to the luminal space using at least two HCO3- exit mechanisms at the luminal membrane. One of the critical transporters needed for all forms of HCO3- secretion across the luminal membrane is the cystic fibrosis transmembrane conductance regulator (CFTR). In the resting state the pancreatic duct, and probably other HCO3- secretory epithelia, absorb HCO3-. Interestingly, CFTR also control this mechanism. In this review, we discuss recent progress in understanding epithelial HCO3- transport, in particular the nature of the luminal transporters and their regulation by CFTR.
Absorption ; Cystic Fibrosis Transmembrane Conductance Regulator ; Diffusion ; Epithelial Cells ; Membranes ; Pancreas ; Pancreatic Ducts ; Phenobarbital

The cystic fibrosis transmembrane conductance regulator (CFTR) is a unique member of the ATP-binding cassette (ABC) transporter superfamily that forms a Cl(-) channel with complex regulation. CFTR is composed of five domains: two membrane-spanning domains (MSDs), two nucleotide-binding domains (NBDs) and a unique regulatory domain (RD). The MSDs assemble to form a low conductance (6-10 pS) anion-selective pore with deep intracellular and shallow extracellular vestibules separated by a selectivity filter. The NBDs form a head-to-tail dimer with two ATP-binding sites (termed sites 1 and 2) located at the dimer interface. Anion flow through CFTR is gated by the interaction of ATP with sites 1 and 2 powering cycles of NBD dimer association and dissociation and hence, conformational changes in the MSDs that open and close the channel pore. The RD is an unstructured domain with multiple consensus phosphorylation sites, phosphorylation of which stimulates CFTR function by enhancing the interaction of ATP with the NBDs. Tight spatial and temporal control of CFTR activity is achieved by macromolecular signalling complexes in which scaffolding proteins colocalise CFTR and plasma membrane receptors with protein kinases and phosphatases. Moreover, a macromolecular complex composed of CFTR and metabolic enzymes (a CFTR metabolon) permits CFTR activity to be coupled tightly to metabolic pathways within cells so that CFTR inhibition conserves vital energy stores. CFTR is expressed in epithelial tissues throughout the body, lining ducts and tubes. It functions to control the quantity and composition of epithelial secretions by driving either the absorption or secretion of salt and water. Of note, in the respiratory airways CFTR plays an additional important role in host defence. Malfunction of CFTR disrupts transepithelial ion transport leading to a wide spectrum of human disease.
Cystic Fibrosis Transmembrane Conductance Regulator ; physiology ; Epithelium ; physiology ; Humans ; Ion Transport ; Phosphorylation ; Protein Interaction Domains and Motifs

Objective: To establish a detection method based on Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) that can sensitively detect the second messenger cyclic AMP (cAMP) in the cytoplasm. Methods: The eukaryotic expression vectors of CFTR and YFP-H148Q / I152L were constructed respectively. FRT cells co-expressing CFTR and YFP-H148Q / I152L were obtained by liposome transfection. The expression of CFTR and YFP-H148Q / I152L in FRT cells was observed by an inverted fluorescence microscopy, and flow cytometry was used to detect the purity of cells; The cell model was identified by the fluorescence quenching kinetics test. The validation of the cell model which could screen CFTR modulators was verified by the fluorescence quenching kinetics experiments. The radioimmunoassay was used to detect the cAMP concentration in cytoplasm after adding CFTR activator. Results: The results of the inverted fluorescence microscope showed that CFTR was expressed in the cell membrane and YFP-H148Q / I152L was expressed in the cytoplasm of FRT cells. The FRT cell model stably co-expressing ANO1 and YFP-H148Q / I152L was successfully constructed. The model could screen CFTR modulators, and the slope of fluorescence change and the concentration of CFTR modulators were in a dose-dependent manner. The slope of the fluorescence could reflect the cAMP concentration in the cytoplasm. The cell model could sensitively detect the intracellular cAMP concentration. Conclusion: The cell model could efficiently and sensitively detect the second messenger cAMP concentration in the cytoplasm, and it provided a simple and efficient method for the study of other targets associated cAMP signal.
Cyclic AMP ; Cystic Fibrosis Transmembrane Conductance Regulator ; Cytoplasm ; Second Messenger Systems

BACKGROUND AND OBJECTIVES: Cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel protein that plays an important role in electrolyte and water transport, whose kinetics and localization are altered in cystic fibrosis (CF). Previous studies showed its presence in the apical domain of ciliated respiratory epithelial cells, and airway secretory glands. The purpose of this study was to characterize the localization of CFTR in the epithelium of nasal polyp of the subjects without phenotypic expression of cystic fibrosis. MAERIALS AND METHODS: Immunohistochemical staining for CFTR, using monoclonal mouse anti-human CFTR, were performed on tissue sections of 4 normal turbinate and nasal polyps from 10 patients who underwent intranasal operation. RESULTS: The nasal polyp epithelium demonstrated a heterogeneous pattern of CFTR expressions, including diffuse or scattered cytoplasmic labeling, very low to undetectable labeling, intense perinuclear staining, and typical apical location. CONCLUSION: These results suggest that abnormal expression and distribution of the CFTR may have a role in the formation of nasal polyp.
Animals ; Chloride Channels ; Cystic Fibrosis Transmembrane Conductance Regulator* ; Cystic Fibrosis* ; Cytoplasm ; Epithelial Cells* ; Epithelium ; Humans ; Kinetics ; Mice ; Nasal Polyps* ; Turbinates

Cystic fibrosis (CF) is a rare autosomal recessive disease with only one pathogenic gene cystic fibrosis transmembrane conductance regulator (CFTR). To identify the potential pathogenic mutations in a Chinese patient with CF, we conducted Sanger sequencing on the genomic DNA of the patient and his parents and detected all 27 coding exons of CFTR and their flanking intronic regions. The patient is a compound heterozygote of c.2909G > A, p.Gly970Asp in exon 18 and c.1210-3C > G in cis with a poly-T of 5T (T5) sequence, 3 bp upstream in intron 9. The splicing effect of c.1210-3C > G was verified via minigene assay in vitro, indicating that wild-type plasmid containing c.1210-3C together with T7 sequence produced a normal transcript and partial exon 10-skipping-transcript, whereas mutant plasmid containing c.1210-3G in cis with T5 sequence caused almost all mRNA to skip exon 10. Overall, c.1210-3C > G, the newly identified pathogenic mutation in our patient, in combination with T5 sequence in cis, affects the CFTR gene splicing and produces nearly no normal transcript in vitro. Moreover, this patient carries a p.Gly970Asp mutation, thus confirming the high-frequency of this mutation in Chinese patients with CF.
China ; Cystic Fibrosis/genetics* ; Cystic Fibrosis Transmembrane Conductance Regulator/genetics* ; Humans ; Mutation ; Poly T ; RNA, Messenger/genetics*

10–30% of patients with pancreatitis can be categorized as idiopathic pancreatitis, and some of them may be due to genetic alterations. Since hereditary pancreatitis develops from pediatric patients with symptoms related to pancreatitis, which usually progresses to chronic pancreatitis around 30 years of age, special attention should be paid to the development of pancreatic cancer in such patients. Up to now, there have been more than 30 genetic alterations associated with pancreatitis. Alterations in protease serine 1 (PRSS1), serine protease inhibitor Kazal type 1 (SPINK1), cystic fibrosis transmembrane conductance regulator (CFTR) and chymotrypsin C (CTRC) are common, which show diversity according to race and region. It is important to understand the characteristics of Korean patients with idiopathic pancreatitis through genetic studies. The purpose of this article is to review the role of genetic variations in the pathophysiology of idiopathic pancreatitis and to survey the results of Korean studies of idiopathic pancreatitis.
Chymotrypsin ; Continental Population Groups ; Cystic Fibrosis Transmembrane Conductance Regulator ; Genetic Variation ; Humans ; Pancreatic Neoplasms ; Pancreatitis* ; Pancreatitis, Chronic ; Serine ; Serine Proteases

An optimal fluid microenvironment in the female reproductive tract is considered to be crucial for successful reproductive events. Fluid absorption and secretion across the reproductive tract epithelia largely depends on electrolyte transport through the apically and basolaterally located ion channels, working together with an array of other transporters. This review will discuss the role of epithelial sodium channel (ENaC) and the cystic fibrosis transmembrane conductance regulator (CFTR) in regulating the fluid volume and composition of the reproductive tract and their importance in various reproductive events such as sperm capacitation and implantation. Disturbance of the fluid microenvironment due to defects or abnormal regulation of these ion channels as causes for a number of pathological conditions, such as ovarian hyperstimulation syndromes, hydrosalpinx and infertility, is also discussed.
Animals ; Cystic Fibrosis Transmembrane Conductance Regulator ; physiology ; Epithelial Sodium Channels ; physiology ; Female ; Fertility ; physiology ; Humans ; Infertility, Female ; physiopathology

The cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel that belongs to the ATP-binding cassette (ABC) transporter superfamily. Defective function of CFTR is responsible for cystic fibrosis (CF), the most common lethal autosomal recessive disorder in Caucasian populations. The disease is manifested in defective chloride transport across the epithelial cells in various tissues. To date, more than 1400 different mutations have been identified as CF-associated. CFTR is regulated by phosphorylation in its regulatory (R) domain, and gated by ATP binding and hydrolysis at its two nucleotide-binding domains (NBD1 and NBD2). Recent studies reveal that the NBDs of CFTR may dimerize as observed in other ABC proteins. Upon dimerization of CFTR's two NBDs, in a head-to-tail configuration, the two ATP-binding pockets (ABP1 and ABP2) are formed by the canonical Walker A and B motifs from one NBD and the signature sequence from the partner NBD. Mutations of the amino acids that interact with ATP reveal that the two ABPs play distinct roles in controlling ATP-dependent gating of CFTR. It was proposed that binding of ATP to the ABP2, which is formed by the Walker A and B in NBD2 and the signature sequence in NBD1, is critical for catalyzing channel opening. While binding of ATP to the ABP1 alone may not increase the opening rate, it does contribute to the stabilization of the open channel conformation. Several disease-associated mutations of the CFTR channel are characterized by gating defects. Understanding how CFTR's two NBDs work together to gate the channel could provide considerable mechanistic information for future pharmacological studies, which could pave the way for tailored drug design for therapeutical interventions in CF.
Adenosine Triphosphate ; physiology ; Animals ; Binding Sites ; Cystic Fibrosis Transmembrane Conductance Regulator ; physiology ; Humans ; Hydrolysis ; Protein Interaction Domains and Motifs ; Protein Multimerization

ObjectiveAcute respiratory distress syndrome (ARDS) is an acute and lethal clinical syndrome that is characterized by the injury of alveolar epithelium, which impairs active fluid transport in the lung, and impedes the reabsorption of edema fluid from the alveolar space. This review aimed to discuss the role of pro-resolving mediators on the regulation of alveolar fluid clearance (AFC) in ARDS.

Data SourcesArticles published up to September 2017 were selected from the PubMed, with the keywords of "alveolar fluid clearance" or "lung edema" or "acute lung injury" or "acute respiratory distress syndrome", and "specialized pro-resolving mediators" or "lipoxin" or "resolvin" or "protectin" or "maresin" or "alveolar epithelial cells" or "aspirin-triggered lipid mediators" or "carbon monoxide and heme oxygenase" or "annexin A1".

Study SelectionWe included all relevant articles published up to September 2017, with no limitation of study design.

ResultsSpecialized pro-resolving mediators (SPMs), as the proinflammatory mediators, not only upregulated epithelial sodium channel, Na,K-ATPase, cystic fibrosis transmembrane conductance regulator (CFTR), and aquaporins levels, but also improved Na,K-ATPase activity to promote AFC in ARDS. In addition to the direct effects on ion channels and pumps of the alveolar epithelium, the SPMs also inhibited the inflammatory cytokine expression and improved the alveolar epithelial cell repair to enhance the AFC in ARDS.

ConclusionsThe present review discusses a novel mechanism for pulmonary edema fluid reabsorption. SPMs might provide new opportunities to design "reabsorption-targeted" therapies with high degrees of precision in controlling ALI/ARDS.