Identifying small molecule regulators of the Proteostasis Network that enhance CFTR protein function

Abstract

Protein homeostasis is established and preserved by a collection of pathways and cellular processes known as the Proteostasis Network (PN). Protein misfolding disorders can arise through a reduced capacity of the PN to appropriately correct the folding, trafficking and degradation of disease‐associated proteins. We target PN pathways using small molecule Proteostasis Regulators (PRs) to identify modulators that confer functional rescue of misfolded proteins. Specifically, we have applied our PN approach to the correction of mutant Cystic Fibrosis Transductance Regulator (CFTR), the causative defect in Cystic Fibrosis (CF). A single mutation, deletion of phenylalanine 508 (F508del), is present in ~87% of all CF patients. The F508del mutation causes defective folding and trafficking, as well as enhanced degradation of the resultant CFTR protein. We carried out a high‐throughput screen using a multiplex gene expression platform to identify PRs that modulate proprietary PN pathway reporters. PRs found to correct mutant CFTR F508del exert effects on one or more pathways within the PN, suggesting they may target different mechanisms important in the maturation of CFTR. We present a novel approach for identifying therapeutics whose mechanism of action involves modulation of the PN. Funded in part by the Cystic Fibrosis Foundation Therapeutics, Inc.