An ovine hepatorenal fibrocystic model of a Meckel-like syndrome associated with dysmorphic primary cilia and TMEM67 mutations

Sci Rep. 2017 May 9;7(1):1601. doi: 10.1038/s41598-017-01519-4.

Abstract

Meckel syndrome (MKS) is an inherited autosomal recessive hepatorenal fibrocystic syndrome, caused by mutations in TMEM67, characterized by occipital encephalocoele, renal cysts, hepatic fibrosis, and polydactyly. Here we describe an ovine model of MKS, with kidney and liver abnormalities, without polydactyly or occipital encephalocoele. Homozygous missense p.(Ile681Asn; Ile687Ser) mutations identified in ovine TMEM67 were pathogenic in zebrafish phenotype rescue assays. Meckelin protein was expressed in affected and unaffected kidney epithelial cells by immunoblotting, and in primary cilia of lamb kidney cyst epithelial cells by immunofluorescence. In contrast to primary cilia of relatively consistent length and morphology in unaffected kidney cells, those of affected cyst-lining cells displayed a range of short and extremely long cilia, as well as abnormal morphologies, such as bulbous regions along the axoneme. Putative cilia fragments were also consistently located within the cyst luminal contents. The abnormal ciliary phenotype was further confirmed in cultured interstitial fibroblasts from affected kidneys. These primary cilia dysmorphologies and length control defects were significantly greater in affected cells compared to unaffected controls. In conclusion, we describe abnormalities involving primary cilia length and morphology in the first reported example of a large animal model of MKS, in which we have identified TMEM67 mutations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abnormalities, Multiple / genetics*
  • Abnormalities, Multiple / pathology
  • Amino Acid Substitution
  • Animals
  • Base Sequence
  • Chromosomes, Mammalian / genetics
  • Cilia / pathology
  • Dandy-Walker Syndrome / genetics*
  • Dandy-Walker Syndrome / pathology
  • Disease Models, Animal
  • Epithelial Cells / metabolism
  • Genetic Loci
  • Golgi Apparatus / metabolism
  • Hepatorenal Syndrome / genetics*
  • Hepatorenal Syndrome / pathology
  • Homozygote
  • Kidney / pathology
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics*
  • Mutation / genetics*
  • Mutation, Missense / genetics
  • Pancreatic Cyst / genetics*
  • Pancreatic Cyst / pathology
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Sheep
  • Zebrafish

Substances

  • Membrane Proteins
  • RNA, Messenger

Supplementary concepts

  • Renal hepatic pancreatic dysplasia Dandy Walker cyst