Structural brain characteristics and gene co-expression analysis: A study with outcome label from normal cognition to mild cognitive impairment.

BACKGROUND: Longitudinal studies reported that some elderly people with normal cognition (NC) converted to mild cognitive impairment (MCI), and some remained normal state (NC_S). The underlying factor for this difference conversion of NC is worthy of exploration METHODS: Eighty-three NC participants were tracked for eight years. Thirty participants transitioned from NC to MCI (NC_MCI). The remaining 53 participants retained an NC_S. The structural brain features and genetic expression of the 83 NC participants were obtained. We applied weighted gene co-expression network analysis (WGCNA) to inquire into the co-expression network of those. Mediator effect analysis of regulatory roles was conducted to inquire into the associations between brain measures, expression values, and clinical scores.

RESULTS: The main results are: 1) 20 brain features and 740 gene expression had significant differences between the two groups, 2) one module including 187 genes had the most correlation with cortical thickness of left superior temporal sulcus (L.STS), 3) NFKBIA and RARA genes were the top two genes that made the greatest contribution to L.STS thickness, and 4) mediating effect was found between the L.STS thickness, the NFKBIA and RARA expression levels, and clinical scores.

CONCLUSION: Our results provide a theoretical foundation based on gene expression and brain imaging for the factors of NC with different outcomes.