Cystic fibrosis disease-specific centiles in 2000 and 2005.
Explore the source record for details and available documents.
Age Factors↗
Biomedical subjects
Frauke Stanke
Publications and source records attributed to Frauke Stanke.
Spontaneous rescue from cystic fibrosis in a mouse model.
BACKGROUND: From the original CftrTgH(neoim)Hgu mutant mouse model with a divergent genetic background (129P2, C57BL/6, MF1) we have generated two inbred CftrTgH(neoim)Hgu mutant strains named CF/1-CftrTgH(neoim)Hgu and CF/3-CftrTgH(neoim)Hgu, which are fertile and show normal growth and lifespan. Initial genome wide scan analysis with microsatellite markers indicated that the two inbred strains differed on the genetic level. In order to further investigate whether these genetic differences have an impact on the disease phenotype of cystic fibrosis we characterised the phenotype of the two inbred strains. RESULTS: Reduced amounts, compared to wild type control animals, of correctly spliced Cftr mRNA were detected in the nasal epithelia, lungs and the intestine of both inbred CftrTgH(neoim)Hgu strains, with higher residual amount observed for CF/1-CftrTgH(neoim)Hgu than CF/3-CftrTgH(neoim)Hgu for every investigated tissue. Accordingly the amounts of wild type Cftr protein in the intestine were 9% for CF/1-CftrTgH(neoim)Hgu and 4% for CF/3-CftrTgH(neoim)Hgu. Unlike the apparent strain and/or tissue specific regulation of Cftr mRNA splicing, short circuit current measurements in the respiratory and intestinal epithelium revealed that both strains have ameliorated the basic defect of cystic fibrosis with a presentation of a normal electrophysiology in both tissues. CONCLUSION: Unlike the outbred CftrTgH(neoim)Hgu insertional mouse model, which displayed the electrophysiological defect in the gastrointestinal and respiratory tracts characteristic of cystic fibrosis, both inbred CftrTgH(neoim)Hgu strains have ameliorated the electrophysiological defect. On the basis of these findings both CF/1-CftrTgH(neoim)Hgu and CF/3-CftrTgH(neoim)Hgu offer an excellent model whereby determination of the minimal levels of protein required for the restoration of the basic defect of cystic fibrosis can be studied, along with the modulating factors which may affect this outcome.
Animals↗
Ex vivo biochemical analysis of CFTR in human rectal biopsies.
This report describes the first biosynthetic analysis of the cystic fibrosis transmembrane conductance regulator (CFTR) in freshly excised human rectal biopsies. Expression of functional CFTR was assessed by intestinal current measurement (ICM) prior to biosynthetic studies. Several structural features of CFTR are found to be comparable to those established in CFTR-expressing cell lines. Interestingly, maturation of CFTR increases substantially in tissue incubated at 26 degrees C. Our data provide a solid basis for future studies on the characterisation of CFTR in pathological cases.
Adolescent↗
The TNFalpha receptor TNFRSF1A and genes encoding the amiloride-sensitive sodium channel ENaC as modulators in cystic fibrosis.
The CFTR mutations in cystic fibrosis (CF) lead to ion transport anomalities which predispose to chronic infection and inflammation of CF airways as the major determinants for morbidity and mortality in CF. Discordant clinical phenotypes of siblings with identical CFTR mutations and the large variability of clinical manifestations of patients who are homozygous for the most common mutation F508del suggest that both environment and genes other than CFTR contribute substantially to CF disease. The prime candidates for genetic modifiers in CF are elements of host defence such as the TNFalpha receptor and of ion transport such as the amiloride-sensitive epithelial sodium channel ENaC, both of which are encoded side by side on 12p13 (TNFRSF1A, SCNN1A) and 16p12 (SCNN1B, SCNN1G). Thirty-seven families with F508del-CFTR homozygous siblings exhibiting extreme clinical phenotypes that had been selected from the 467 pairs of the European CF Twin and Sibling Study were genotyped at 12p13 and 16p12 markers. The ENaC was identified as a modulator of CF by transmission disequilibrium at SCNN1G and association with CF phenotype intrapair discordance at SCNN1B. Family-based and case-control analyses and sequencing of SCNN1A and TNFRSF1A uncovered an association of the TNFRSF1A intron 1 haplotype with disease severity. Carriers of risk haplotypes were underrepresented suggesting a strong impact of both loci on survival. The finding that TNFRSF1A, SCNN1B and SCNN1G are clinically relevant modulators of CF disease supports current concepts that the depletion of airway surface liquid and inadequate host inflammatory responses trigger pulmonary disease in CF.
Adolescent↗
Genetic modifiers in cystic fibrosis.
Explore the source record for details and available documents.
Chromosomes, Human, Pair 19↗
The CLCA gene locus as a modulator of the gastrointestinal basic defect in cystic fibrosis.
To determine whether the CLCA gene family of calcium-activated chloride channels is a modulator of the basic defect of cystic fibrosis (CF), an association study was performed with polymorphic microsatellite markers covering a 40-Mbp region spanning the CLCA gene locus on human chromosome 1p in CF patients displaying CF transmembrane conductance regulator (CFTR)-independent residual chloride conductance in gastrointestinal epithelia. Statistically significant association of the electrophysiological phenotype with the allele distribution of markers 5' of and within the CLCA locus was observed. Transmission disequilibrium and the significance of the association decreased within the locus from hCLCA2 towards hCLCA4. Expression of hCLCA1 and hCLCA4 in human rectal mucosa was proven by microarray analysis. The CLCA gene region was identified to encode mediators of DIDS-sensitive anion conductance in the human gastrointestinal tract that modulate the CF basic defect.
Alleles↗
Instability of the insertional mutation in CftrTgH(neoim)Hgu cystic fibrosis mouse model.
BACKGROUND: A major boost to the cystic fibrosis disease research was given by the generation of various mouse models using gene targeting in embryonal stem cells. Moreover, the introduction of the same mutation on different inbred strains generating congenic strains facilitated the search for modifier genes. From the original CftrTgH(neoim)Hgu CF mouse model we have generated using strict brother x sister mating two inbred CftrTgH(neoim)Hgu mouse lines (CF/1 and CF/3). Thereafter, the insertional mutation was introgressed from CF/3 into three inbred backgrounds (C57BL/6, BALB/c, DBA/2J) generating congenic animals. In every backcross cycle germline transmission of the insertional mutation was monitored by direct probing the insertion via Southern RFLP. In order to bypass this time consuming procedure we devised an alternative PCR based protocol whereby mouse strains are differentiated at the Cftr locus by Cftr intragenic microsatellite genotypes that are tightly linked to the disrupted locus. RESULTS: Using this method we were able to identify animals carrying the insertional mutation based upon the differential haplotypic backgrounds of the three inbred strains and the mutant CftrTgH(neoim)Hgu at the Cftr locus. Moreover, this method facilitated the identification of the precise vector excision from the disrupted Cftr locus in two out of 57 typed animals. This reversion to wild type status took place without any loss of sequence revealing the instability of insertional mutations during the production of congenic animals. CONCLUSIONS: We present intragenic microsatellite markers as a tool for fast and efficient identification of the introgressed locus of interest in the recipient strain during congenic animal breeding. Moreover, the same genotyping method allowed the identification of a vector excision event, posing questions on the stability of insertional mutations in mice.
Animals↗
Basic protocol for transepithelial nasal potential difference measurements.
Transepithelial nasal potential difference (NPD) measurements assess ion conductance in the upper respiratory epithelium. NPD is useful in assisting in the diagnosis of classical and atypical cystic fibrosis (CF) and of cystic fibrosis transmembrane regulator (CFTR)-related disorders, as well as for monitoring the effect of pharmacological agents and gene transfer approaches to correct the abnormalities of ion transport in CF. The article summarizes the objectives and the principle of NPD measurements, describes a hands-on protocol of the procedure and provides quality control measures, practical hints and troubleshooting.
Clinical Protocols↗
Ex vivo CF diagnosis by intestinal current measurements (ICM) in small aperture, circulating Ussing chambers.
Intestinal current measurements (ICM) on rectal suction biopsies are a tool for the ex vivo diagnosis of classical and atypical cystic fibrosis (CF). We present the basic ICM protocol, typical tracings and their interpretation. The ICM technique allows the registration of CF-induced changes in electrogenic transepithelial ion transport (Cl-, HCO3-, K+) in a Cl- secretory epithelium, and on the basis of pharmacological criteria, is able to discriminate between CFTR-mediated Cl- secretion and secretion through alternative anion channels. ICM is particularly useful for the classification of individuals with CF-like clinical features with equivocal sweat test values and/or no or one identifiable CFTR mutation.
Chlorides↗