Whole transcriptome miRNA profiling of Coronavirus Disease 2019 (COVID-19) patient plasma.

The purpose of this study was to identify miRNAs that were dysregulated after the onset of COVID-19 and thus potentially be used for risk stratification (i.e., mortality). Therefore, we conducted a multi-center, retrospective longitudinal cohort study enrolling 142 patients with laboratory-confirmed SARS-CoV-2 infection who presented to two Canadian hospitals from May 2020 – December 2020 along with a cohort of 27 SARS-CoV-2 patients with mild upper respiratory tract symptoms and 69 SARS-CoV-2-negative patients from the ICU. Blood was biobanked from SARS-CoV-2 positive patients in the emergency department (mild), ward (moderate) or intensive care unit (severe). Assessment of miRNA expression and co-regulatory network generation revealed significant transcriptome dyregulation in pateints with severe COVID-19 that was largely different from SARS-CoV-2 negative patients in the ICU. Platelet reduced plasma from either: (1) SARS-CoV-2 negative patients with mild upper respiratory tract symptoms, (2) patients with mild COVID-19, (3) patients with moderate COVID-19, (4) patients with severe COVID-19, and (5) SARS-CoV-2 negative patients from the ICU with upper respiratory tract illnesses was taken from a -80 freezer and thawed on ice. Sample Groups: (1) n=30 SARS-CoV-2 negative patients with mild upper respiratory tract symptoms (2) n=14 patients with mild COVID-19 (3) n=15 patients with moderate COVID-19 (4) n=45 patients with severe COVID-19 (5) n=31 SARS-CoV-2 negative patients from the ICU with upper respiratory tract symptoms. A total of 30uL of thawed plasma was co-incubated with 1:1 volumes of HTG Plasma Lysis buffer (pre-warmed to 50 degrees celsius) and 1/10th v/v proteinase K for three hours at 50 degrees celsius with shaking (200rpm).