Pathophysiological pathway differences in children who present with COVID-19 ARDS compared to COVID -19 induced MIS-C

Abstract

COVID-19 has infected more than 275 million worldwide (at the beginning of 2022). Children appear less susceptible to COVID-19 and present with milder symptoms. Cases of children with COVID-19 developing clinical features of Kawasaki-disease have been described. Here we utilise Mass Spectrometry proteomics to determine the plasma proteins expressed in healthy children pre-pandemic, children with multisystem inflammatory syndrome (MIS-C) and children with COVID-19 induced ARDS. Pathway analyses were performed to determine the affected pathways. 76 proteins are differentially expressed across the groups, with 85 and 52 proteins specific to MIS-C and COVID-19 ARDS, respectively. Complement and coagulation activation are implicated in these clinical phenotypes, however there was significant contribution of FcGR and BCR activation in MIS-C and scavenging of haem and retinoid metabolism in COVID-19 ARDS. We show global proteomic differences in MIS-C and COVID-ARDS, although both show complement and coagulation dysregulation. The results contribute to our understanding of MIS-C and COVID-19 ARDS in children.

Fig. 1. Hierarchical clustering of all detected proteins.

a Unsupervised hierarchical clustering analysis for the 319 protein identifications using the local assay library. Relative expression patterns obtained using Euclidean distance; Green: proteins with decreased expression; Red: proteins with increased expression; b Principal Component Analysis of data from a. The axis of PC1, PC2 and PC3 represented the first three principal components.

Fig. 2. Overall differentially expressed proteins.

a Heatmap of the 76 differentially expressed proteins from the local assay library identified using unadjusted p value and fold-change with two-sided t test. The clustering patterns were obtained using a Euclidean-based distance and complete linkage; Green: proteins with decreased expression; Red: proteins with increased expression; b Heatmap of the 44 differentially expressed proteins from the local assay library identified using p values adjusted for multiple comparisons by using two-sided t test with Benjamini-Hochberg correction.

Fig. 3. Enriched pathways between COVID-19 ARDS and Healthy Group.

Top 10 enriched pathways for the 52 differentially expressed proteins based on the unadjusted p value and fold-change comparison between COVID-19 ARDS Group and Healthy Group, ranked in increasing order of their p values (determined using two-sided t test) from left-to-right. (a Reactome pathway analysis; b STRING pathway analysis). Top 10 enriched pathways for the 17 differentially expressed proteins based on the adjusted p value (using two-sided t test adjusted for multiple comparison with Benjamini-Hochberg correction) comparison between COVID-19 ARDS Group and Healthy Group, ranked in increasing order of their p values from left-to-right. (c Reactome pathway analysis; d STRING pathway analysis). The size of the bar in each graph indicates the proportion of proteins in that pathway that are up- or down-regulated in our study, the number reported at the top of each bar is the specific number of proteins in that pathway affected. Dark grey: proteins with relative increased expression in COVID-19 ARDS Group; Light grey: proteins with relative decreased expression in COVID-19 ARDS Group. Black line with a white circle: -Log10 (p value). Indicated pathways suggest biological pathways that are most impacted as a result of COVID-19 ARDS.

Fig. 4. Enriched pathways between MIS-C and Healthy Group.

Top ten enriched pathways for the 85 differentially expressed proteins based on the unadjusted p value and fold change comparison between MIS-C Group and Healthy Group, ranked in increasing order of their p values (determined using two-sided t test) from left-to-right. (a Reactome pathway analysis; b STRING pathway analysis). Top 10 enriched pathways for the 26 differentially expressed proteins based on the adjusted p value (using two-sided t test adjusted for multiple comparisons with Benjamini-Hochberg correction) comparison between MIS-C Group and Healthy Group, ranked in increasing order of their p values from left to right. (c Reactome pathway analysis; d STRING pathway analysis). The size of the bar in each graph indicates the proportion of proteins in that pathway that are up- or down-regulated in our study, the number reported at the top of each bar is the specific number of proteins in that pathway affected. Light grey: proteins with relative decreased expression in MIS-C Group; Dark grey: proteins with relative increased expression in MIS-C Group; Black line with a white circle: -Log10 (p value); Number in each column represents the total proteins number of the pathway. Indicated pathways suggest biological pathways that are most impacted as a result of COVID-19 ARDS.