RESUMEN
Mucocele formation in dogs is a unique and enigmatic muco-obstructive disease of the gallbladder caused by the amassment of abnormal mucus that bears striking pathological similarity to cystic fibrosis. We investigated the role of cystic fibrosis transmembrane conductance regulatory protein (CFTR) in the pathogenesis of this disease. The location and frequency of disease-associated variants in the coding region of CFTR were compared using whole genome sequence data from 2,642 dogs representing breeds at low-risk, high-risk, or with confirmed disease. Expression, localization, and ion transport activity of CFTR were quantified in control and mucocele gallbladders by NanoString, Western blotting, immunofluorescence imaging, and studies in Ussing chambers. Our results establish a significant loss of CFTR-dependent anion secretion by mucocele gallbladder mucosa. A significantly lower quantity of CFTR protein was demonstrated relative to E-cadherin in mucocele compared with control gallbladder mucosa. Immunofluorescence identified CFTR along the apical membrane of epithelial cells in control gallbladders but not in mucocele gallbladder epithelium. Decreases in mRNA copy number for CFTR were accompanied by decreases in mRNA for the Cl-/[Formula: see text] exchanger SLC26A3, K+ channels (KCNQ1, KCNN4), and vasoactive intestinal polypeptide receptor (VIPR1), which suggest a driving force for change in secretory function of gallbladder epithelial cells in the pathogenesis of mucocele formation. There were no significant differences in CFTR gene variant frequency, type, or predicted impact comparing low-risk, high-risk, and definitively diagnosed groups of dogs. This study describes a unique, naturally occurring muco-obstructive disease of the canine gallbladder, with uncanny similarity to cystic fibrosis, and driven by the underlying failure of CFTR function.NEW & NOTEWORTHY Cystic fibrosis transmembrane conductance regulatory protein (CFTR) genomic variants and expression of mRNA, protein, and electrogenic anion secretory activity of CFTR were characterized in dog gallbladder. Acquired inhibition of CFTR expression by gallbladder epithelium was identified as underpinning a naturally occurring muco-obstructive disease of the dog gallbladder that bears striking pathological similarity to animal models of cystic fibrosis.
Asunto(s)
Regulador de Conductancia de Transmembrana de Fibrosis Quística , Fibrosis Quística , Enfermedades de los Perros , Vesícula Biliar , Animales , Perros , Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Regulador de Conductancia de Transmembrana de Fibrosis Quística/metabolismo , Fibrosis Quística/metabolismo , Fibrosis Quística/genética , Fibrosis Quística/veterinaria , Vesícula Biliar/metabolismo , Vesícula Biliar/patología , Enfermedades de los Perros/metabolismo , Enfermedades de los Perros/genética , Mucocele/metabolismo , Mucocele/genética , Mucocele/veterinaria , Enfermedades de la Vesícula Biliar/veterinaria , Enfermedades de la Vesícula Biliar/metabolismo , Enfermedades de la Vesícula Biliar/genética , Enfermedades de la Vesícula Biliar/patologíaRESUMEN
Although the Guide suggests changing rodent cage components every 2 wk, it states that "decreased sanitation frequency may be justified if the microenvironment in the cages, under the condition of use ..., is not compromised." The purpose of this study was to evaluate extended sanitation intervals of cage components (automated watering valve, wire bar lid, and filter top) of mouse individually ventilated caging (IVCs) at our institution. We hypothesized that there would be no significant difference in relative light units measured by ATP luminometry of these cage components at the control time point of 14 d as compared with each extended time interval: 28, 56, and 84 d. In addition, for automated watering valves, the study was extended to 168 d. We also hypothesized that time-and-motion studies performed by moving to a sanitation interval of 84 d for all components would result in substantial time and cost savings. The components of a total of 24 cages containing 4 or 5 mice each were swabbed, and an ATP luminometer was used to detect organic matter. We found no significant differences in organic matter load between 14 d and all other time points for all cage components. Our time- and cost-savings analysis found that extending the sanitation interval of cage components from every 2 wk (14 d) to every 3 mo (84 d) for every 10,000 cages would save about 3,000 technician hours annually, for a total annual labor cost savings of about $100,000. This study is the first to validate the extended sanitation interval of automated watering valves and confirms the findings of previous studies that validated the extended sanitation frequency of wire bar lids and filter tops of rodent IVCs. Overall, extending the sanitation frequency of cage components reduces workload of animal care staff without compromising the cage microenvironment.