The workflow of procedure. I) The workflow to construct the miRNA-mRNA regulatory network. The bipartite miRNA-mRNA regulatory network was constructed by pair-wise correlation coefficient analysis between miRNA and mRNA expression profiles. II) The workflow to construct the miRNA-miRNA synergistic network. The miRNA-miRNA synergistic network was constructed based on co-regulation of target genes and GO function enrichment of co-regulated target genes. III) The analysis of the miRNA-miRNA synergistic network. We compared topological measurements between age-related-miRNAs and non age–related–miRNAs, and identified miRNA synergistic modules from the miRNA-miRNA synergistic network by Cfinder.