Hallmarks of therapeutic management of the cystic fibrosis functional landscape

Abstract

The cystic fibrosis (CF) transmembrane conductance regulator (CFTR) protein does not operate in isolation, rather in a dynamic network of interacting components that impact its synthesis, folding, stability, intracellular location and function, referred to herein as the 'CFTR Functional Landscape (CFFL)'. For the prominent F508del mutation, many of these interactors are deeply connected to a protein fold management system, the proteostasis network (PN). However, CF encompasses an additional 2000 CFTR variants distributed along its entire coding sequence (referred to as CFTR2), and each variant contributes a differential liability to PN management of CFTR and to a protein 'social network' (SN) that directs the probability of the (patho)physiologic events that impact ion transport in each cell, tissue and patient in health and disease. Recognition of the importance of the PN and SN in driving the unique patient CFFL leading to disease highlights the importance of precision medicine in therapeutic management of disease progression. We take the view herein that it is not CFTR, rather the PN/SN, and their impact on the CFFL, that are the key physiologic forces driving onset and clinical progression of CF. We posit that a deep understanding of each patients PN/SN gained by merging genomic, proteomic (mass spectrometry (MS)), and high-content microscopy (HCM) technologies in the context of novel network learning algorithms will lead to a paradigm shift in CF clinical management. This should allow for generation of new classes of patient specific PN/SN directed therapeutics for personalized management of the CFFL in the clinic.

Keywords: Bioinformatics; Chaperones; Cystic fibrosis; Epigenetics; Epiproteomics; Genomics; High-content microscopy; High-throughput screening; Mass spectrometry; Protein folding; Proteomics; Proteostasis; System biology.

Figure 1. The CF(TR) Functional Landscape (CFFL) Hallmark Challenge

The proteostasis network (PN)-coupled social network (SN-) of CFTR (Hallmarks 2 and 3), constitute the CFTR Functional Landscape (CFFL) which is optimized by biology so that a given cell, tissue and individual displays a particular functional genotype to phenotype relationship that occurs as healthy for wild-type CFTR, or as ‘variations on a theme’ in CF disease for each CFTR variant in each patient, providing an associated ‘Functional Liability and Probability’ (Hallmark 3) and its many responses to the environment (Hallmark 4) to achieve therapeutic efficacy (Hallmark 5), in what we refer to as the ‘CFFL Challenge’ Environment.