An in vivo study of novel genetic modifiers in autosomal recessive polycystic kidney disease (ARPKD)

Autosomal Recessive Polycystic Kidney Disease (ARPKD) is a rare genetic disorder that manifests with bilaterally enlarged, cystic kidneys, hepatic fibrosis and pulmonary hypoplasia, with death reported in around 30 – 50% of affected neonates. Mutations in PKHD1 and DZIP1L have been identified as causative genes for ARPKD, with the protein products of both genes localising to the primary cilium. Ciliary signalling pathways, such as Wnt signalling, have been investigated to dissect potential molecular mechanisms of ARPKD, however, these remain unclear. To overcome this, researchers have tried to develop rodent models that replicate human ARPKD and thus far, this has proven challenging. Using our current understanding regarding pathogenic variants in ARPKD patients, we have developed the novel Pkhd1T37M/T37M mouse model that carries the most common and severe truncating mutation in human ARPKD. For this study, we aimed to characterise this model by performing experiments in the kidney, liver and lung, across different developmental stages, as presented in human ARPKD. From our data, we found that the kidney phenotype in Pkhd1T37M/T37M mice was overall mild, presenting as tubular dilation from around P2, and cytoskeletal defects in aged mice. Furthermore, novel Pkhd1 targets, including Muc1, Tacstd2 and Epor, were identified via RNA-sequencing analysis with metabolic pathways such as oxidative phosphorylation appearing dysregulated. In the liver, Pkhd1T37M/T37M mice presented progressive liver fibrosis and increased canonical Wnt signalling. Excitingly, for the first time, we provide evidence that the lung may be a primary characteristic of ARPKD, rather than a secondary consequence, with mutations in Pkhd1 resulting in changes in the gross morphological structure of Pkhd1T37M/T37M mouse lungs and aberrant expression of key PKD and Wnt signalling genes, including Pkd1, Atmin and Vangl2. Interestingly, RNA-sequencing analysis also identified Aqp2, Foxf1 and Igfbp2 as novel Pkhd1 targets in the lung, as well as dysregulation of STAT3 signalling in Pkhd1T37M/T37M mice. Together, this data further highlights potential mechanisms of action for the lung phenotype and sets the ground for future investigations to dissect these relationships. Overall, our study shows that the Pkhd1T37M/T37M mouse exhibits an ARPKD-like phenotype and could be a useful tool to advance our understanding of ARPKD and the potential molecular mechanisms involved.

Citation

Malik, S.A. (2025) An in vivo study of novel genetic modifiers in autosomal recessive polycystic kidney disease (ARPKD). University of Wolverhampton. https://wlv.openrepository.com/handle/2436/625960

Publisher

University of Wolverhampton

URI

https://wlv.openrepository.com/handle/2436/625960

Type

Thesis or dissertation

Language

en

Description

A thesis submitted in partial fulfilment of the requirement of the University of Wolverhampton for the degree of Doctor of Philosophy.

Collections

Theses and Dissertations