Cystic fibrosis (CF) is a recessive disease that affects multiple organs. It is caused by mutations in CFTR. Animal modeling of this disease has been challenging, with species-and strain-specific differences in organ biology and CFTR function influencing the emergence of disease pathology. Here, we report the phenotype of a CFTR-knockout ferret model of CF. Neonatal CFTR-knockout ferrets demonstrated many of the characteristics of human CF disease, including defective airway chloride transport and submucosal gland fluid secretion; variably penetrant meconium ileus (MI); pancreatic, liver, and vas deferens disease; and a predisposition to lung infection in the early postnatal period. Severe malabsorption by the gastrointestinal (GI) tract was the primary cause of death in CFTR-knockout kits that escaped MI. Elevated liver function tests in CFTR-knockout kits were corrected by oral administration of ursodeoxycholic acid, and the addition of an oral proton-pump inhibitor improved weight gain and survival. To overcome the limitations imposed by the severe intestinal phenotype, we cloned 4 gut-corrected transgenic CFTR-knockout kits that expressed ferret CFTR specifically in the intestine. One clone passed feces normally and demonstrated no detectable ferret CFTR expression in the lung or liver. The animals described in this study are likely to be useful tools for dissecting CF disease pathogenesis and developing treatments.

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Reactive oxygen species (ROS) generated by NADPH oxidases (Nox) have been implicated in the regulation of signal transduction. However, the cellular mechanisms that link Nox activation with plasma membrane receptor signaling remain poorly defined. We have found that Nox2-derived ROS influence the formation of an active interleukin-1 (IL-1) receptor complex in the endosomal compartment by directing the H2O2-dependent binding of TRAF6 to the IL-1R1/MyD88 complex. Clearance of both superoxide and H2O2 from within the endosomal compartment significantly abrogated IL-1β-dependent IKK and NF-κB activation. MyD88-dependent endocytosis of IL-1R1 following IL-1β binding was required for the redox-dependent formation of an active endosomal receptor complex competent for IKK and NF-κB activation. Small interfering RNAs to either MyD88 or Rac1 inhibited IL-1β induction of endosomal superoxide and NF-κB activation. However, MyD88 and Rac1 appear to be recruited independently to IL-1R1 following ligand stimulation. In this context, MyD88 binding was required for inducing endocytosis of IL-1R1 following ligand binding, while Rac1 facilitated the recruitment of Nox2 into the endosomal compartment and subsequent redox-dependent recruitment of TRAF6 to the MyD88/IL-1R1 complex. The identification of Nox-active endosomes helps explain how subcellular compartmentalization of redox signals can be used to direct receptor activation from the plasma membrane.

Liver transplantation is the only therapeutic strategy for many inherited and acquired diseases. The formation of reactive oxygen species following ischemia/reperfusion is a cause of hepatocellular injury during transplantation. This report describes the therapeutic application of mitochondrial superoxide dismutase gene transfer to the liver for acute ischemia/reperfusion injury. Recombinant adenoviral expression of mitochondrial superoxide dismutase in mouse liver prior to lobar ischemia/reperfusion significantly reduced acute liver damage and associated redox activation of both NF-kappaB and AP1. These immediate early transcription factors represent common pathways by which cells respond to environmental stress. This work provides the foundation for redox-mediated gene therapies directed at ameliorating ischemia/reperfusion injury and associated acute rejection in orthotopic liver transplantation.

Diabetes is a common comorbidity in cystic fibrosis (CF) that worsens prognosis. The lack of an animal model for CF-related diabetes (CFRD) has made it difficult to dissect how the onset of pancreatic pathology influences the emergence of CFRD. We evaluated the structure and function of the neonatal CF endocrine pancreas using a new CFTR-knockout ferret model. Although CF kits are born with only mild exocrine pancreas disease, progressive exocrine and endocrine pancreatic loss during the first months of life was associated with pancreatic inflammation, spontaneous hyperglycemia, and glucose intolerance. Interestingly, prior to major exocrine pancreas disease, CF kits demonstrated significant abnormalities in blood glucose and insulin regulation, including diminished first-phase and accentuated peak insulin secretion in response to glucose, elevated peak glucose levels following glucose challenge, and variably elevated insulin and C-peptide levels in the nonfasted state. Although there was no difference in lobular insulin and glucagon expression between genotypes at birth, significant alterations in the frequencies of small and large islets were observed. Newborn cultured CF islets demonstrated dysregulated glucose-dependent insulin secretion in comparison to controls, suggesting intrinsic abnormalities in CF islets. These findings demonstrate that early abnormalities exist in the regulation of insulin secretion by the CF endocrine pancreas. IntroductionCystic fibrosis (CF) is caused by defects in the CF transmembrane conductance regulator (CFTR) chloride channel. Cystic fibrosisrelated diabetes (CFRD) is a common complication of CF and affects 20%-25% of adolescents and 40%-50% of individuals over 30 years of age (1,2). CFRD is associated with worsening clinical status, including reduced pulmonary function, increased frequency of pulmonary exacerbations, and a decline in nutritional status (3-7). Furthermore, CFRD leads to increased mortality compared with CF patients without diabetes (4,8). Thus, early diagnosis and treatment are vital to improving clinical outcome of CFRD patients.While the pathophysiology of CFRD is multifactorial, delayed insulin secretion appears to be a key hallmark of disease progression (9-12), and the health of CF patients is improved by insulin therapy prior to and following diagnosis of overt diabetes (13,14). Partial insulin deficiency occurs in part due to islet loss associated with exocrine pancreas disease (15-18). However, CF pancreata at CFRD autopsy demonstrate that remaining islets contain roughly half the number of insulin-positive cells found in non-CF controls (17,18), and this degree of β cell loss is thought to be insufficient to explain diabetes (19). Thus, insulin deficiency in CFRD is relative and not absolute. All stages of CFRD are characterized by abnormalities in circulating insulin levels (10,12,20,21). Impaired first-phase insulin (IFPI) responses are common in CFRD patients, but also occur in approximately 50% of CF children with normal glucose tolerance (9). Cu...