Screening for differentially expressed microRNAs in BALF and blood samples of infected COVID-19 ARDS patients by small RNA deep sequencing.

BACKGROUND: The pandemic COVID-19 has caused a high mortality rate and poses a significant threat to the population of the entire world. Due to the novelty of this disease, the pathogenic mechanism of the disease and the host cell's response are not yet fully known, so lack of evidence prevents a definitive conclusion about treatment strategies. The current study employed a small RNA deep-sequencing approach for screening differentially expressed microRNA (miRNA) in blood and bronchoalveolar fluid (BALF) samples of acute respiratory distress syndrome (ARDS) patients. METHODS: In this study, BALF and blood samples were taken from patients with ARDS (n = 5). Control samples were those with suspected lung cancer candidates for lung biopsy (n = 3). Illumina high-throughput (HiSeq 2000) sequencing was performed to identify known and novel miRNAs differentially expressed in the blood and BALFs of ARDS patients compared with controls. RESULTS: Results showed 2234 and 8324 miRNAs were differentially expressed in blood and BALF samples, respectively. In BALF samples, miR-282, miR-15-5p, miR-4485-3p, miR-483-3p, miR-6891-5p, miR-200c, miR-4463, miR-483-5p, and miR-98-5p were upregulated and miR-15a-5p, miR-548c-5p, miR-548d-3p, miR-365a-3p, miR-3939, miR-514-b-5p, miR-513a-3p, miR-513a-5p, miR-664a-3p, and miR-766-3p were downregulated. On the contrary, in blood samples miR-15b-5p, miR-18a-3p, miR-486-3p, miR-486-5p, miR-146a-5p, miR-16-2-3p, miR-6501-5p, miR-365-3p, miR-618, and miR-623 were top upregulated miRNAs and miR-21-5p, miR-142a-3p, miR-181-a, miR-31-5p, miR-99-5p, miR-342-5p, miR-183-5p, miR-627-5p, and miR-144-3p were downregulated miRNAs. Network functional analysis for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), in ARDS patients' blood and BALF samples, showed that the target genes were more involved in activating inflammatory and apoptosis process. CONCLUSION: Based on our results, the transcriptome profile of ARDS patients would be a valuable source for understanding molecular mechanisms of host response and developing clinical guidance on anti-inflammatory medication.

Identification of novel loss of function variants in MBOAT7 resulting in intellectual disability.

The membrane bound O-acyltransferase domain-containing 7 (MBOAT7) gene codes for an enzyme involved in regulating arachidonic acid incorporation in lysophosphatidylinositol. Patients with homozygous nonsense mutations in MBOAT7 have intellectual disability (ID) accompanied with seizure and autism. Accumulating evidences obtained from human genetic studies have shown that MBOAT7 is also involved in fatty liver disease. Here we identified two novel homozygous variants in MBOAT7, NM_024298.5: c.1062C>A; p.(Tyr354*) and c.1135del; p.(Leu379Trpfs*9), in two unrelated Iranian families by means of whole exome sequencing. Sanger sequencing was performed to confirm the identified variants and also to investigate whether they co-segregate with the patients' phenotypes. To understand the functional consequences of these changes, we overexpressed recombinant wild type MBOAT7 and mutants in vitro and showed these mutations resulted in abolished protein synthesis and expression, indicating a complete loss of function. Albeit, we did not trace any liver diseases in our patients, but presence of globus pallidus signal changes in Magnetic Resonance Images might be indicative of metabolic changes as a result of loss of MBOAT7 expression in hepatic cells. These signal changes could also help as an important marker of MBOAT7 deficiency while analyzing the genomic data of patients with similar phenotypes.