Pharmacotherapies for people with cystic fibrosis (pwCF) who have premature termination codons (PTCs) in the cystic fibrosis transmembrane conductance regulator (CFTR) gene are under development. Thus far, clinical studies focused on compounds that induce translational readthrough (RT) at the mRNA PTC location. Recent studies using primary airway cells showed that PTC functional restoration can be achieved through combining compounds with multiple mode-of-actions. Here, we assessed induction of CFTR function in PTC-containing intestinal organoids using compounds targeting RT, nonsense mediated decay (NMD) and CFTR protein modulation. Rescue of PTC CFTR protein was assessed by the forskolin-induced swelling of 12 intestinal organoid cultures, homozygous or compound heterozygous for distinct PTC mutations. Effects of compounds on mRNA CFTR level was assessed by RT-qPCRs. Whilst response varied between donors, significant rescue of CFTR function was achieved for most donors with the quintuple combination of a commercially available pharmacological equivalent of the RT compound (ELX-02-disulfate or ELX-02ds), NMD inhibitor SMG1i, correctors VX-445 and VX-661 and potentiator VX-770. The quintuple combination of pharmacotherapies reached swelling quantities higher than the mean swelling of three VX-809/VX-770-rescued F508del/F508del organoid cultures, indicating level of rescue is of clinical relevance as VX-770/VX-809-mediated F508del/F508del rescue in organoids correlate with substantial improvement of clinical outcome. Whilst variation in efficacy was observed between genotypes as well as within genotypes, the data suggests that strong pharmacological rescue of PTC requires a combination of drugs that target RT, NMD and protein function. We anticipate that this novel approach can strongly contribute to the development of CFTR modulating treatments for pwCF that currently have no CFTR modulating treatments available.

Functional Restoration of CFTR Nonsense Mutations in Intestinal Organoids

Rationale
IL-33 and its receptor IL-1RL1 are important asthma genes. T helper-2 (TH2) cells present in asthmatic airway wall contribute to chronic inflammation and epithelial remodeling. TH2 cells express IL-1RL1 and respond to IL-33 by increased cytokine production upon stimulation. We aimed to test the extent of the IL-33-driven modification of Th2 cell activation, and whether the asthma-susceptibility alleles of IL1RL affect this response. 
Methods
CD4+ T cells isolated from PBMCs of 16 healthy donors and 16 asthma patients, stratified for IL-1RL1 high and low risk-genotypes, were differentiated into TH2 cells in vitro, and re-stimulated by CD3/CD28-crosslinking in presence or absence of 100 ng/mL rhIL-33. Gene expression was assessed by RNA-sequencing, and subsequently analyzed using limma in R comparing high and low risk genotype and asthma versus controls. Membrane bound IL1-RL1-b protein levels were determined using FACS.
Results
Presence of IL-33 during CD3/CD28 stimulation of TH2 effector cells in vitro results in extensive changes in gene expression, affecting up to 40% of the transcriptomic changes induced by TH2 cell activation. The fold change in gene expression induced by IL-33 was significantly higher in TH2 cells carrying the IL-1RL1 risk haplotype compared to the IL-1RL protective haplotype. However, the identity of the IL-33 regulated genes was not different between the IL-1RL1 haplotype groups. In addition, significant differences in IL-33 regulated genes were observed between Th2 cells derived from healthy controls and asthma patients. At the protein level, the change in TH2 cells expressing the transmembrane IL-1RL1 receptor was higher in asthma patients than in controls . 
Conclusions
The asthma-associated IL-1RL1 haplotype strongly increases the sensitivity of TH2 effector cell for IL-33-mediated regulation of gene expression, while disease status also has an independent effect. IL-33 in the airway wall will contribute to chronic inflammation maintained by TH2 effector cells mainly in patients with asthma carrying the IL-1RL1 asthma risk alleles. 


Enhanced IL-33 response in differentiated human TH2 cells carrying the IL-1RL1 asthma risk genotype

Exposure of the human airways to cigarette smoke (CS) is the major etiological risk factor for developing devastating lung diseases such as Chronic Obstructive Pulmonary Disease (COPD). Although previous studies demonstrated aberrant mitochondrial morphology and impaired mitochondrial function in response to exposure of human airway epithelial cells to CS, to what extent the pathways regulating mitochondrial content and quality control are impacted is unknown. Therefore, we assessed the activity and abundance of key constituents of mitochondrial metabolic pathways, as well as transcript and protein levels of critical molecules regulating mitochondrial biogenesis and mitophagy in undifferentiated human primary bronchial epithelial cells (PBECs; provided by PLUC facility MUMC+, Maastricht) of COPD (n=5) and non-COPD (n=7) subjects, in undifferentiated PBECs of non-COPD subjects (n=4) exposed to CS extract (CSE) (0-1-2%), and in air-liquid interface differentiated PBECs of non-COPD subjects (n=4) exposed to CS (1 Marlboro Red cigarette) by machine smoking according to the Health Canadian Intense Regime. Evaluation of the abundance of prominent regulators controlling mitochondrial metabolic pathways revealed no outstanding differences at gene and protein level in PBECs of COPD versus non-COPD subjects. Although mitochondrial DNA copy number was unaltered, CSE exposure, dose- and time-dependently, downregulated mRNA levels of mitochondrial biogenesis markers and upregulated protein and transcript abundance of autophagy regulators in undifferentiated PBECs. Moreover, we observed increased metabolic enzyme activity in response to CSE exposure, respectively of hydroxyacyl-coenzyme A dehydrogenase and phosphofructokinase. These alterations were, at least in part, recapitulated in CS exposed differentiated PBECs. Collectively, these data show that CS(E) exposure disrupts the molecular regulation of mitochondrial metabolism in cells of the human airways.

Underline digital video library

Functional Restoration of CFTR Nonsense Mutations in Intestinal Organoids

Enhanced IL-33 response in differentiated human TH2 cells carrying the IL-1RL1 asthma risk genotype

Exposure to cigarette smoke disrupts the molecular regulation of mitochondrial metabolism in epithelial cells of the human airways

Stay up to date with the latest Underline news!

PRESENTATIONS

CONFERENCES

COMPANY

RESOURCES