Dataset Information

Distinct proteostasis states drive pharmacologic chaperone susceptibility for Cystic Fibrosis Transmembrane Conductance Regulator misfolding mutants

ABSTRACT: Pharmacological chaperones represent a class of therapeutic compounds for treating protein misfolding diseases. One of the most prominent examples is the FDA-approved pharmacological chaperone lumacaftor (VX-809), which has transformed cystic fibrosis (CF) therapy. CF is a fatal disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR). VX-809 corrects folding of F508del CFTR, the most common patient mutation, yet F508del exhibits only mild VX-809 response. In contrast, rarer mutations P67L and L206W are hyper-responsive to VX-809, while G85E is non-responsive. Despite the clinical success of VX-809, the mechanistic origin for the distinct susceptibility of mutants remains unclear. Here, we use interactomics to characterize the impact of VX-809 on proteostasis interactions of P67L and L206W and compare these to F508del and G85E. We determine hyper-responsive mutations P67L and L206W exhibit decreased interactions with proteasomal, and autophagy degradation machinery compared to F508del and G85E. We then show inhibiting the proteasome attenuates P67L and L206W VX-809 response. Our data suggests a previously unidentified but required role for protein degradation in VX-809 correction. Furthermore, we present an approach for identifying proteostasis characteristics of mutant-specific therapeutic response to pharmacological chaperones.

INSTRUMENT(S): Orbitrap Exploris 480

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture, Early Embryonic Cell

DISEASE(S): Cystic Fibrosis

SUBMITTER: Eli McDonald

LAB HEAD: Lars Plate

PROVIDER: PXD032836 | Pride | 2022-05-04

REPOSITORIES: Pride

ACCESS DATA

Similar Datasets

Project description:Cystic Fibrosis (CF) is a genetic disorder CF is caused by mutations of the gene encoding for the cystic fibrosis transmembrane conductance regulator protein (CFTR), a transmembrane anion channel expressed at the apical membrane of several organs, including the epithelial cells of the airway. CFTR mutations result in dysfunctional ion transport across the apical membrane at the surface of the epithelia, generating thickened and dehydrated secretions. In the lung, this leads to a decrease in the mucociliary clearance, favoring bacterial colonization and progressive obstruction of the duct. Although over 2000 CFTR variants have been identified so far, the most common mutation is a deletion of the phenylalanine in position 508 (F508del), which shows an allelic frequency of around 90% among CF patients. F508del-CFTR is incorrectly folded, causing its retention at the endoplasmic reticulum (ER) and subsequent proteasomal degradation. Among the several drugs available in CF pharmacological treatment, VX-809 (commercial name Lumacaftor) is the most used drug for patients carrying F508del-CFTR mutation. This drug corrects the aberrant folding of F508del-CFTR by favoring the correct intramolecular interactions, thus enabling a higher number of copies of the defective protein to reach the plasma membrane. Localization of Organelle Proteins by Isotope Tagging after Differential ultra-Centrifugation (LOPIT-DC, https://doi.org/10.1038/s41467-018-08191-w) workflow was used to study the spatial localization of proteins in the CFBE41o- cells and how it is impacted by CFTR rescue triggered by VX-809. LOPIT-DC is a powerful and well-established tool for the investigation of the spatial distribution of global proteome within cells, which combines subcellular fractionation based on differential centrifugation, quantitative mass spectrometry, and machine learning. Its application provides a global snapshot of the steady-state subcelluler distribution of proteins. The aim of this project is to identify proteins that change their cellular localization in association with the treatment, to uncover molecules that play a role in the trafficking of the defective CFTR to the plasma membrane.

Project description:Lipid intermediates derived from sphingolipid metabolism are crucial regulators of mitochondrial function from yeast to humans. Among these intermediates, trans-2-hexadecenal (t-2hex) within the sphingolipid degradation pathway exhibits remarkable efficiency in inducing mitochondria-mediated cell death. In yeast cell cultures, the addition of t-2-hex triggers complete disintegration of the mitochondrial network, leading to subsequent cell death. This effect is particularly pronounced in yeast cells lacking the activity of the t-2-hex degrading enzyme, Hfd1. However, the molecular mechanisms of t-2-hex induction of mitochondrial dysfunction are completely unknown. In this project, we want to exploit the unprecedented power of yeast genetics to unveil novel genetic determinants involved in t-2-hex's pro-apoptotic function. To accomplish this, we employed the SATAY method, which combines saturated transposon mutagenesis with high-throughput sequencing to functionally explore the yeast genome. In our screening approach, hfd1 mutant cells harboring a plasmid-encoded inducible MiniDs transposon were induced by galactose, resulting in extensive integration of the transposon throughout the yeast genome. Cells with the plasmid excised and the transposon genomically integrated were pooled together, creating a high-density transposon library comprising approximately 2.3E+06 independent insertion mutants. Subsequently, the pooled mutant library was subjected to treatment with the mitochondria-mediated death inducer, t-2-hexadecenal. As a control, cells were also incubated with the solvent dimethyl sulfoxide (DMSO), in which hexadecenal is dissolved. Following the treatments, cells were collected for genomic DNA extraction and digestion, using restriction enzymes with frequent four-base pair recognition sites. The resulting library fragments were circularized using T4 DNA ligase, and the transposon-genome junctions were selectively amplified through PCR with outward-facing primers specific to the transposon. Finally, the pooled and purified amplicons were subjected to massive sequencing on an Illumina MiSeq platform. The obtained sequences were then aligned to the reference genome of Saccharomyces cerevisiae, allowing for the mapping of transposon insertions and the calculation of transposon counts per gene. This project enabled the identification of genes required for the resistance and toxicity to t-2hex.

Dataset Information

Distinct proteostasis states drive pharmacologic chaperone susceptibility for Cystic Fibrosis Transmembrane Conductance Regulator misfolding mutants

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure