Project description:The lack of rapidly progressive murine models reflecting the classical infantile disease in ARPKD inhibits progress to understanding pathogenesis. The role that primary cilia play in PKD is also controversial. Here new mouse and rat models, generated by interbreeding appropriate ARPKD and ADPKD strains are characterized; better reflecting the severe human disease. Analysis of mRNA expression in the individual ARPKD and ADPKD models, and the combined mice highlighted different disrupted pathways but with a commonality of dysregulated mechanisms associated with primary cilia. These models will help understand ARPKD and improve preclinical testing for this disease. The study also, in unbiased way, reinforces that cilia are important for pathogenesis in both disorders.
Project description:Autosomal dominant polycystic kidney disease (ADPKD) is a common cause of ESRD. Affected individuals inherit a defective copy of either the PKD1 or PKD2 gene, encoding the proteins polycystin?1 (PC1) or polycystin?2 (PC2) respectively. PC1 and PC2 are secreted on urinary exosome?like vesicles (ELVs) (100nm diameter vesicles), where PC1 is present in a cleaved form and may be complexed with PC2. Label free quantitative proteomic studies of urine ELVs in an initial discovery cohort (13 PKD1 and 18 Normals), revealed that of 2008 ELV proteins, nine (0.32%) showed a statistically significant difference between PKD1 and normals at a p<0.025. PC1 was reduced to 54% of the normal level (p<0.02) and PC2 reduced to 53% (p<0.001). TMEM2, a protein with homology to fibrocystin, the product of the polycystic hepatic and kidney disease (PKHD1) gene, is increased 2.1 fold (p<0.025). The PC1/TMEM2 ratio correlated inversely with height adjusted total kidney volume (HtTKV) in the discovery cohort and the ratio of PC1/TMEM2 or PC2/TMEM2 could be used to distinguish PKD1 from normals in a confirmation cohort. In summary, this study suggests that a test based on the urine exosomal PC1/TMEM2 or PC2/TMEM2 ratio may have utility in the diagnosis and perhaps monitoring of PKD1.
Project description:Autosomal dominant polycystic kidney disease (ADPKD) is a common cause of ESRD. Affected individuals inherit a defective copy of either the PKD1 or PKD2 gene, encoding the proteins polycystin?1 (PC1) or polycystin?2 (PC2) respectively. PC1 and PC2 are secreted on urinary exosome?like vesicles (ELVs) (100nm diameter vesicles), where PC1 is present in a cleaved form and may be complexed with PC2. Label free quantitative proteomic studies of urine ELVs in an initial discovery cohort (13 PKD1 and 18 Normals), revealed that of 2008 ELV proteins, nine (0.32%) showed a statistically significant difference between PKD1 and normals at a p<0.025. PC1 was reduced to 54% of the normal level (p<0.02) and PC2 reduced to 53% (p<0.001). TMEM2, a protein with homology to fibrocystin, the product of the polycystic hepatic and kidney disease (PKHD1) gene, is increased 2.1 fold (p<0.025). The PC1/TMEM2 ratio correlated inversely with height adjusted total kidney volume (HtTKV) in the discovery cohort and the ratio of PC1/TMEM2 or PC2/TMEM2 could be used to distinguish PKD1 from normals in a confirmation cohort. In summary, this study suggests that a test based on the urine exosomal PC1/TMEM2 or PC2/TMEM2 ratio may have utility in the diagnosis and perhaps monitoring of PKD1.
Project description:The Pkd1 gene was inactivated by tamoxifen at postnatal day 30 (P30) to generate a chronic-onset conditional Pkd1 gene knockout mouse model. Without any intervention, micro cysts could be detected adjacent to renal medulla-corticomedullary junction in Pkd1-/- mice until P180 and cystic phenotype is severe at P300. However, under dehydration situation, the cyst growth was more accelerated and progressive. The dehydration protocol resulted in Pkd1-/- mice varying degrees of sweating and weight loss. Mice that were not provided water during the day (water at night (D-WAN)) and mice that had access to water during the day (water all time (D-WAT)) showed significantly more weight loss compared with the control Pkd1-/- mice, although they drank more water at night. Interestingly, although D-WAN Pkd1-/- mice and D-WAT Pkd1-/- mice lost approximately body weights after one-day dehydration, while cyst enlargement and renal dysfunction was much more severe in the D-WAN Pkd1-/- mice after two-month intervention.
Project description:Somatic mutations in non-malignant tissues are selected for because they confer increased clonal fitness, however, it is uncertain if these clones can benefit organ health. Here, ultra-deep targeted sequencing of 150 liver samples from 30 chronic liver disease patients revealed recurrent somatic mutations. PKD1 mutations were observed in 30% of patients, whereas they were only detected in 1.3% of hepatocellular carcinomas (HCCs). To interrogate tumor suppressor functionality, we perturbed PKD1 in two HCC cell lines and six in vivo models, in some cases showing that PKD1 loss protected against HCC, but in most cases showing no impact. However, Pkd1 haploinsufficiency accelerated regeneration after partial hepatectomy. We tested Pkd1 in fatty liver disease, showing that Pkd1 loss was protective against steatosis and glucose intolerance. Mechanistically, Pkd1 loss selectively increased mTOR signaling without SREBP activation. In summary, PKD1 mutations in cirrhotic livers exert adaptive functionality without increasing transformation risk.
Project description:Somatic mutations in non-malignant tissues are selected for because they confer increased clonal fitness, however, it is uncertain if these clones can benefit organ health. Here, ultra-deep targeted sequencing of 150 liver samples from 30 chronic liver disease patients revealed recurrent somatic mutations. PKD1 mutations were observed in 30% of patients, whereas they were only detected in 1.3% of hepatocellular carcinomas (HCCs). To interrogate tumor suppressor functionality, we perturbed PKD1 in two HCC cell lines and six in vivo models, in some cases showing that PKD1 loss protected against HCC, but in most cases showing no impact. However, Pkd1 haploinsufficiency accelerated regeneration after partial hepatectomy. We tested Pkd1 in fatty liver disease, showing that Pkd1 loss was protective against steatosis and glucose intolerance. Mechanistically, Pkd1 loss selectively increased mTOR signaling without SREBP activation. In summary, PKD1 mutations in cirrhotic livers exert adaptive functionality without increasing transformation risk.
Project description:This study sough to understand the differential gene expression profile of Pkd1 mutant mice kidneys in the setting of miR 17~92 deletion