Project description:A reduced sense of smell has been reported in people with cystic fibrosis (CF). These olfactory defects have largely been attributed to secondary manifestations of the disease, such as inflammation of the nasal mucosa. Here we show that CFTR, the gene responsible for CF, is expressed in proliferating olfactory human cells and that newborn CFTR null pigs display ultrastructural abnormalities in the olfactory epithelium and olfactory bulbs. In the absence of CFTR, olfactory sensory neurons still produce odor-evoked activity, but mutant animals display defective odor-guided suckling behavior after birth. Consistent with epithelial changes, we found a reduced expression of genes implicated in cell cycle and development in globose basal cells (GBCs), the neurogenic progenitor cells in the olfactory epithelium. Targeted sequencing revealed enhanced CFTR expression in the subpopulation of GBCs that is actively proliferating. Furthermore, CFTR loss caused a global reduction in the number of sensory neurons and altered olfactory receptors expression. Our findings highlight a previously unknown role of CFTR in olfactory system function by regulating progenitor cell proliferation in the olfactory epithelium.
Project description:A reduced sense of smell has been reported in people with cystic fibrosis (CF). These olfactory defects have largely been attributed to secondary manifestations of the disease, such as inflammation of the nasal mucosa. Here we show that CFTR, the gene responsible for CF, is expressed in proliferating olfactory human cells and that newborn CFTR null pigs display ultrastructural abnormalities in the olfactory epithelium and olfactory bulbs. In the absence of CFTR, olfactory sensory neurons still produce odor-evoked activity, but mutant animals display defective odor-guided suckling behavior after birth. Consistent with epithelial changes, we found a reduced expression of genes implicated in cell cycle and development in globose basal cells (GBCs), the neurogenic progenitor cells in the olfactory epithelium. Targeted sequencing revealed enhanced CFTR expression in the subpopulation of GBCs that is actively proliferating. Furthermore, CFTR loss caused a global reduction in the number of sensory neurons and altered olfactory receptors expression. Our findings highlight a previously unknown role of CFTR in olfactory system function by regulating progenitor cell proliferation in the olfactory epithelium.
Project description:BackgroundCystic fibrosis (CF) is a rare condition in Asians. Since 1985, only about 30 Chinese patients have been reported with molecular confirmation.MethodUsing our in-house next-generation sequencing (NGS) pipeline for childhood bronchiectasis, we identified disease-causing CFTR mutations in CF patients in Hong Kong. After identifying p.I1023R in multiple patients, haplotype analysis was performed with genome-wide microarray to ascertain the likelihood of this being a founder mutation. We also assessed the processing and gating activity of the mutant protein by Western hybridization and patch-clamp test.ResultsMolecular diagnoses were confirmed in four patients, three of whom shared a missense mutation: CFTR:c.3068T>G:p.I1023R. The results suggested that p.I1023R is a founder mutation in southern Han Chinese. In addition, the processing and gating activity of the mutant protein was assessed by gel electrophoresis and a patch-clamp test. The mutant protein exhibited trafficking defects, suggesting that the dysfunction is caused by reduced cell surface expression of the fully glycosylated proteins.ConclusionTogether with other previously reported mutations, the specific founder mutation presented herein suggests a unique CFTR mutation spectrum in the southern Chinese populations, and this finding has vital implications for improving molecular testing and mutation-specific treatments for Chinese patients with CF.
Project description:Cystic fibrosis (CF) is a genetic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR). Cystic fibrosis-related diabetes (CFRD) is the most common comorbidity, affecting more than 50% of adult CF patients. Despite this high prevalence, the etiology of CFRD remains incompletely understood. Studies in young CF children show pancreatic islet disorganization, abnormal glucose tolerance, and delayed first-phase insulin secretion suggesting that islet dysfunction is an early feature of CF. Since insulin-producing pancreatic β-cells express very low levels of CFTR, CFRD likely results from β-cell extrinsic factors. In the vicinity of β-cells, CFTR is expressed in both the exocrine pancreas and the immune system. In the exocrine pancreas, CFTR mutations lead to the obstruction of the pancreatic ductal canal, inflammation, and immune cell infiltration, ultimately causing the destruction of the exocrine pancreas and remodeling of islets. Both inflammation and ductal cells have a direct effect on insulin secretion and could participate in CFRD development. CFTR mutations are also associated with inflammatory responses and excessive cytokine production by various immune cells, which infiltrate the pancreas and exert a negative impact on insulin secretion, causing dysregulation of glucose homeostasis in CF adults. In addition, the function of macrophages in shaping pancreatic islet development may be impaired by CFTR mutations, further contributing to the pancreatic islet structural defects as well as impaired first-phase insulin secretion observed in very young children. This review discusses the different factors that may contribute to CFRD.
Project description:This multi-center study will compare multi-target DNA and quantitative FIT stool-based testing to colonoscopy in individuals with Cystic Fibrosis (CF) undergoing colon cancer screening with colonoscopy. The primary endpoint is detection of any adenomas, including advanced adenomas and colorectal cancer (CRC).
Project description:Cystic fibrosis (CF) is caused by loss-of-function mutations in the CFTR (CF transmembrane regulator) gene. Pharmacologic therapies directed at CFTR have been developed but are not effective for mutations that result in little or no mRNA or protein expression. Cell therapy is a potential mutation-agnostic approach to treatment. One strategy is to harvest human bronchial epithelial cells (HBECs) for gene addition or genetic correction, followed by expansion and engraftment. This approach will require cells to grow extensively while retaining their ability to reconstitute CFTR activity. We hypothesized that conditionally reprogrammed cell (CRC) technology, namely growth in the presence of irradiated feeder cells and a Rho kinase inhibitor, would enable expansion while maintaining cell capacity to express functional CFTR. Our goal was to compare expression of the basal cell marker NGFR (nerve growth factor receptor) and three-dimensional bronchosphere colony-forming efficiency (CFE) in early- and later-passage HBECs grown using nonproprietary bronchial epithelial growth medium or the CRC method. Cell number and CFTR activity were determined in a competitive repopulation assay employing chimeric air-liquid interface cultures. HBECs expanded using the CRC method expressed the highest NGFR levels, had the greatest 3D colony-forming efficiency at later passage, generated greater cell numbers in chimeric cultures, and most effectively reconstituted CFTR activity. In our study, the HBEC air-liquid interface model, an informative testing platform proven vital for the development of other CF therapies, illustrated that cells grown by CRC technology or equivalent methods may be useful for cell therapy of CF.