Functional and structural analysis of cytokine-selective IL6ST defects that cause recessive hyper-IgE syndrome.
J Allergy Clin Immunol
; 148(2): 585-598, 2021 08.
Article
in En
| MEDLINE
| ID: mdl-33771552
ABSTRACT
BACKGROUND:
Biallelic variants in IL6ST, encoding GP130, cause a recessive form of hyper-IgE syndrome (HIES) characterized by high IgE level, eosinophilia, defective acute phase response, susceptibility to bacterial infections, and skeletal abnormalities due to cytokine-selective loss of function in GP130, with defective IL-6 and IL-11 and variable oncostatin M (OSM) and IL-27 levels but sparing leukemia inhibitory factor (LIF) signaling.OBJECTIVE:
Our aim was to understand the functional and structural impact of recessive HIES-associated IL6ST variants.METHODS:
We investigated a patient with HIES by using exome, genome, and RNA sequencing. Functional assays assessed IL-6, IL-11, IL-27, OSM, LIF, CT-1, CLC, and CNTF signaling. Molecular dynamics simulations and structural modeling of GP130 cytokine receptor complexes were performed.RESULTS:
We identified a patient with compound heterozygous novel missense variants in IL6ST (p.Ala517Pro and the exon-skipping null variant p.Gly484_Pro518delinsArg). The p.Ala517Pro variant resulted in a more profound IL-6- and IL-11-dominated signaling defect than did the previously identified recessive HIES IL6ST variants p.Asn404Tyr and p.Pro498Leu. Molecular dynamics simulations suggested that the p.Ala517Pro and p.Asn404Tyr variants result in increased flexibility of the extracellular membrane-proximal domains of GP130. We propose a structural model that explains the cytokine selectivity of pathogenic IL6ST variants that result in recessive HIES. The variants destabilized the conformation of the hexameric cytokine receptor complexes, whereas the trimeric LIF-GP130-LIFR complex remained stable through an additional membrane-proximal interaction. Deletion of this membrane-proximal interaction site in GP130 consequently caused additional defective LIF signaling and Stüve-Wiedemann syndrome.CONCLUSION:
Our data provide a structural basis to understand clinical phenotypes in patients with IL6ST variants.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Mutation, Missense
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Cytokine Receptor gp130
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Molecular Dynamics Simulation
/
Job Syndrome
Type of study:
Clinical_trials
/
Prognostic_studies
Limits:
Child
/
Humans
/
Male
Language:
En
Journal:
J Allergy Clin Immunol
Year:
2021
Type:
Article
Affiliation country:
United kingdom