microRNA profile of inflammatory response in COVID-19 participants

COVID-19 is associated with a cytokine storm leading to a pro-inflammatory response. Little is known about the miRNA expression profile associated with inflammatory signalling pathways i.e. high vascular endothelin growth factor (VEGF) and/ or creatine kinase (CK) in people with a history of COVID-19.

To identify the signalling profile of circulating miRNAs associated with a high inflammatory level and analyse their pro-inflammatory signalling pathways in people following COVID-19 infection.

VEGF and CK levels were assessed in a cohort of 84 participants who tested positive for COVID-19 within the past 18 months. Plasma samples were pooled in the following groups: ‘high VEGF’ (>115pg/mL), ‘high CK’ (>200U/L) and ‘low inflammation’ (standard cardiovascular/metabolic biomarkers within normal range). High inflammation VEGF and CK versus low inflammation pools were analysed. Global miRNA was extracted from pooled plasma samples and analysed using the TaqMan Array Human MicroRNA A cards. Using Ingenuity Pathway Analysis (IPA, Qiagen), we identified relevant miRNA-regulated target genes associated with pro-inflammation.

Twelve participants (15%, age: 58 ± 6.8 years, 9 females) were identified as having high VEGF (153±43 pg/mL), 13 participants (15%, age: 61 ± 7.02 years, 3 females) with high CK (281 ± 81U/L) and 20 participants (24%, age: 59 ± 6.26 years, 12 females) had low inflammation. Significant upregulated expression of 98 miRNAs was identified in the high VEGF group and two miRNAs in the CK group. Significant downregulated expression of five miRNAs was identified in the high VEGF group, and 178 in the high CK group. IPA analysis revealed changes in expression levels of circulating miRNAs relate to inflammatory pathways, i.e. miR-196b (associated with inhibition of angiogenesis) was 2.16-fold downregulated in high VEGF and 3.24-fold downregulated in high CK groups. This downregulation of miR-196b supports the knowledge of the angiogenic/ vasculogenic role of VEGF. Additionally, high circulating CK is linked to general inflammation which is known to promote vascular growth in acute inflammation environments. Conversely, miR-361 was 429.00-fold upregulated in high VEGF groups and 4.00-fold downregulated in high CK groups. Knockdown of miR-361 leads to increased neovascularisation, however the high VEGF group show increased miR-361 expression.

Pro-inflammatory-associated miRNAs are identified in people following COVID-19 infection. Exploring miRNA signatures and their involvement in pro-inflammatory signalling pathways improves understanding of the inflammatory response in middle age and older adults with a history of COVID-19.