Back to Search
Start Over
Rescue by 4-phenylbutyrate of several misfolded creatine transporter-1 variants linked to the creatine transporter deficiency syndrome.
- Source :
-
Neuropharmacology [Neuropharmacology] 2019 Dec 15; Vol. 161, pp. 107572. Date of Electronic Publication: 2019 Mar 15. - Publication Year :
- 2019
-
Abstract
- Diseases arising from misfolding of SLC6 transporters have been reported over recent years, e.g. folding-deficient mutants of the dopamine transporter and of the glycine transporter-2 cause infantile/juvenile Parkinsonism dystonia and hyperekplexia, respectively. Mutations in the coding sequence of the human creatine transporter-1 (hCRT-1/SLC6A8) gene result in a creatine transporter deficiency syndrome, which varies in its clinical manifestation from epilepsy, mental retardation, autism, development delay and motor dysfunction to gastrointestinal symptoms. Some of the mutations in hCRT-1 occur at residues, which are highly conserved across the SLC6 family. Here, we examined 16 clinically relevant hCRT-1 variants to verify the conjecture that they were misfolded and that this folding defect was amenable to correction. Confocal microscopy imaging revealed that the heterologously expressed YFP-tagged mutant CRTs were trapped in the endoplasmic reticulum (ER), co-localised with the ER-resident chaperone calnexin. In contrast, the wild type hCRT-1 reached the plasma membrane. Preincubation of transiently transfected HEK293 cells with the chemical chaperone 4-phenylbutyrate (4-PBA) restored ER export and surface expression of as well as substrate uptake by several folding-deficient CRT-1 mutants. A representative mutant (hCRT-1-P544L) was expressed in rat primary hippocampal neurons to verify pharmacochaperoning in a target cell: 4-PBA promoted the delivery of hCRT-1-P544L to the neurite extensions. These observations show that several folding-deficient hCRT-1 mutants can be rescued. This proof-of-principle justifies the search for additional pharmacochaperones to restore folding of 4PBA-unresponsive hCRT-1 mutants. Finally, 4-PBA is an approved drug in paediatric use: this provides a rationale for translating the current insights into clinical trials. This article is part of the issue entitled 'Special Issue on Neurotransmitter Transporters'.<br /> (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Subjects :
- Animals
Brain Diseases, Metabolic, Inborn genetics
Calnexin metabolism
Cell Membrane metabolism
Creatine genetics
Endoplasmic Reticulum metabolism
Endoplasmic Reticulum ultrastructure
HEK293 Cells
Humans
Mental Retardation, X-Linked genetics
Mutation genetics
Nerve Tissue Proteins genetics
Neurites metabolism
Neurons metabolism
Plasma Membrane Neurotransmitter Transport Proteins drug effects
Plasma Membrane Neurotransmitter Transport Proteins genetics
Primary Cell Culture
Proteostasis Deficiencies genetics
Rats
Brain Diseases, Metabolic, Inborn drug therapy
Creatine deficiency
Mental Retardation, X-Linked drug therapy
Nerve Tissue Proteins drug effects
Phenylbutyrates pharmacology
Plasma Membrane Neurotransmitter Transport Proteins deficiency
Proteostasis Deficiencies drug therapy
Subjects
Details
- Language :
- English
- ISSN :
- 1873-7064
- Volume :
- 161
- Database :
- MEDLINE
- Journal :
- Neuropharmacology
- Publication Type :
- Academic Journal
- Accession number :
- 30885608
- Full Text :
- https://doi.org/10.1016/j.neuropharm.2019.03.015