ABSTRACT
The etiopathogenesis of severe COVID-19 remains unknown. Indeed given major confounding factors (age and co-morbidities), true drivers of this condition have remained elusive. Here, we employ an unprecedented multi-omics analysis, combined with artificial intelligence, in a young patient cohort where major co-morbidities have been excluded at the onset. Here, we established a three-tier cohort of individuals younger than 50 years without major comorbidities. These included 47 "critical" (in the ICU under mechanical ventilation) and 25 "non-critical" (in a noncritical care ward) COVID-19 patients as well as 22 healthy individuals. The analyses included whole-genome sequencing, whole-blood RNA sequencing, plasma and blood mononuclear cells proteomics, cytokine profiling and high-throughput immunophenotyping. An ensemble of machine learning, deep learning, quantum annealing and structural causal modeling led to key findings. Critical patients were characterized by exacerbated inflammation, perturbed lymphoid/myeloid compartments, coagulation and viral cell biology. Within a unique gene signature that differentiated critical from noncritical patients, several driver genes promoted severe COVID-19 among which the upregulated metalloprotease ADAM9 was key. This gene signature was replicated in an independent cohort of 81 critical and 73 recovered COVID-19 patients, as were ADAM9 transcripts, soluble form and proteolytic activity. Ex vivo ADAM9 inhibition affected SARS-CoV-2 uptake and replication in human lung epithelial cells. In conclusion, within a young, otherwise healthy, COVID-19 cohort, we provide the landscape of biological perturbations in vivo where a unique gene signature differentiated critical from non-critical patients. The key driver, ADAM9, interfered with SARS-CoV-2 biology. A repositioning strategy for anti-ADAM9 therapeutic is feasible. One sentence summaryEtiopathogenesis of severe COVID19 in a young patient population devoid of comorbidities.
ABSTRACT
Deletion-induced hemizygosity may unmask deleterious autosomal recessive variants and be a cause of the phenotypic variability observed in microdeletion syndromes. We performed complete exome sequencing (WES) analysis to examine this possibility in a patient with 1p13.2 microdeletion. Since the patient displayed clinical features suggestive of Noonan Syndrome (NS), we also used WES to rule out the presence of pathogenic variants in any of the genes associated with the different types of NS. We concluded that the clinical findings could be attributed solely to the 1p13.2 haploinsufficiency. Retrospective analysis of other nine reported patients with 1p13.2 microdeletions showed that six of them also presented some characteristics of NS. In all these cases, the deleted segment included the NRAS gene. Gain-of-function mutations of NRAS gene are causally related to NS type 6. Thus, it is conceivable that NRAS haploinsufficiency and gain-of-function mutations may have similar clinical consequences. The same phenomenon has been described for two other genes belonging to the Ras/MAPK pathway: MAP2K2 and SHOC2. In conclusion, we here report genotype-phenotype correlations in patients with chromosome 1p13.2 microdeletions and we propose that NRAS may be a critical gene for the NS characteristics in the patients.
