title: Targeted rescue of a polycystic kidney disease mutation by lysosomal inhibition.
abstract: Autosomal dominant polycystic kidney disease (ADPKD) is the most common monogenic cause of end-stage renal disease. The molecular pathogenesis of ADPKD is not completely known, and there is no approved therapy. To date, there is limited knowledge concerning the molecular consequences of specific disease-causing mutations. Here we show that the ADPKD missense variant TRPP2(D511V) greatly reduces TRPP2 protein stability, and that TRPP2(D511V) function can be rescued in vivo by small molecules targeting the TRPP2 degradation pathway. Expression of the TRPP2(D511V) protein was significantly reduced compared to wild-type TRPP2. Inhibition of lysosomal degradation of TRPP2(D511V) by the US Food and Drug Administration (FDA)-approved drug chloroquine strongly increased TRPP2 protein levels in vitro. The validation of these results in vivo requires appropriate animal models. However, there are currently no mouse models harboring human PKD2 missense mutations, and screening for chemical rescue of patient mutations in rodent models is time-consuming and expensive. Therefore, we developed a Drosophila melanogaster model expressing the ortholog of TRPP2(D511V) to test chemical rescue of mutant TRPP2 in vivo. Notably, chloroquine was sufficient to improve the phenotype of flies expressing mutant TRPP2. Thus, this proof-of-concept study highlights the potential of directed therapeutic approaches for ADPKD, and provides a rapid-throughput experimental model to screen PKD2 patient mutations and small molecules in vivo.
authors.affiliation: Renal Division, Department of Medicine, Medical Center, University of Freiburg, Freiburg, Germany; Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany; Faculty of Biology, University of Freiburg, Freiburg, Germany. Electronic address: alexis.hofherr@uniklinik-freiburg.de.
authors.forename: Alexis
authors.initials: A
authors.lastname: Hofherr
authors.affiliation: Department of Translational Pulmonology, Translational Lung Research Center Heidelberg, University of Heidelberg, Heidelberg, Germany.
authors.forename: Claudius J
authors.initials: CJ
authors.lastname: Wagner
authors.affiliation: Division of Nephrology, University of Maryland School of Medicine, Baltimore, Maryland, USA.
authors.forename: Terry
authors.initials: T
authors.lastname: Watnick
authors.affiliation: Renal Division, Department of Medicine, Medical Center, University of Freiburg, Freiburg, Germany. Electronic address: michael.koettgen@uniklinik-freiburg.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Köttgen
mesh_terms: D000818:Animals; D018501:Antirheumatic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D002738:Chloroquine / Q000494:pharmacology / Q000627:therapeutic use*; D004331:Drosophila melanogaster; D004353:Drug Evaluation, Preclinical; D005260:Female; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D008247:Lysosomes / Q000187:drug effects / Q000378:metabolism; D008297:Male; D020125:Mutation, Missense; D016891:Polycystic Kidney, Autosomal Dominant / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism; D055550:Protein Stability; D050396:TRPP Cation Channels / Q000235:genetics* / Q000378:metabolism
chemical_list: D018501:Antirheumatic Agents; D002738:Chloroquine; D050396:TRPP Cation Channels
keywords: PKD2; chloroquine; lysosome; polycystic kidney disease