Hub genes comprise the highly interconnected nodes within gene co-expression modules and have been shown to be functionally significant [98]. In our study, candidate hub genes were defined by their intramodular connectivity, the strength of which is measured by the absolute value of the Pearson correlation (r≥ 0.8) between individual gene expression and ME, referred also as a module membership (MM) [99, 100]. The upper quartile of transcripts with the highest MM in each AD-significant module (employed for both mRNA and miRNA modules) was chosen as criterion for selection of candidate hub genes.
