3.4 Critical lipid Co-expression network modules closely
correlated with ICP
To clarify the relationships between lipids profile and the clinical
characteristics of our study population, we next constructed Weighted
Gene Co-expression Network Analysis (WGCNA) to identify clusters or
modules that have similar expression patterns. In this analysis, we
obtained 14 modules and the result showed that most lipids were
clustered in turquoise, yellow and pink modules (Fig S2). Among the 14
modules, the pink module and purple module showed a significant positive
correlation with TBA, ALT and AST levels, whereas the salmon module
negatively correlated with TBA, ALT and AST levels (Fig 4A). A total of
30 lipids were included in these three modules, and we identified 11
differentially co-expressed lipids overlapped with the dysregulated
lipids in both mild and severe ICP group (Fig S3A). Next, the CytoScape
was used to screen hub lipids in pink, purple and salmon module based on
the MCC algorithm. The top 4 lipids in the MCC algorithm were identified
as hub lipids. As shown in Fig 4B, we identified PE (18:0p/20:1), dMePE
(20:1p/16:0), PE (16:0p/22:1) and PE (38:2e) as hub lipids in the pink
module. Among these four hub lipids, the expression level of PE
(18:0p/20:1), dMePE (20:1p/16:0) and PE (16:0p/22:1) was significantly
elevated in the mild and severe ICP group (Fig 4C). The network diagram
also depicts the hub lipids in purple and salmon module (Fig S3B and Fig
S3C).