Differential Expression and miRNA-Gene Interactions in Early and Late Mild Cognitive Impairment

Area of Science:

• Neuroscience
• Genetics
• Molecular Biology

Background:

• Mild cognitive impairment (MCI) and Alzheimer's Disease (AD) are complex neurodegenerative disorders with incompletely understood molecular underpinnings.
• While genes like APOE, APP, and PSEN1 are implicated, epigenetic factors and microRNAs (miRNAs) are increasingly recognized for their role in neurodegeneration.
• Existing research highlights the need for integrated analyses of gene and miRNA expression to elucidate disease mechanisms.

Purpose of the Study:

• To identify differentially expressed genes and miRNAs in individuals with early and late mild cognitive impairment (EMCI and LMCI) compared to healthy controls and AD patients.
• To explore potential miRNA-gene interactions involved in cognitive impairment and neurodegeneration.
• To contribute to a deeper understanding of the molecular architecture of MCI and AD.

Main Methods:

• Differential expression analysis (DEA) was performed on gene and miRNA profiles obtained from microarray and RNA-Seq data.
• Gene expression data from the ADNI Cohort included healthy individuals, EMCI, LMCI, and AD patients.
• miRNA expression data from healthy individuals and AD patients were extracted from public RNA-Seq datasets. The limma and edgeR packages were utilized for DEA.

Main Results:

• Eight differentially expressed genes (AGER, LINC00483, MMP19, CATSPER1, ARFGAP1, GPER1, PHLPP2, TRPM2) were identified between EMCI and LMCI patients (FDR p-value < 0.05).
• Five dysregulated miRNAs were identified (FDR p-value < 0.002).
• All identified miRNAs interact with the previously identified differentially expressed genes, suggesting a coordinated regulatory network.

Conclusions:

• The study successfully identified specific genes and miRNAs that are dysregulated in early and late stages of MCI.
• The findings highlight a network of miRNA-gene interactions potentially playing a significant role in cognitive decline and neurodegenerative processes.
• This integrative transcriptomic analysis provides novel insights into the molecular mechanisms underlying MCI and AD, paving the way for future research and therapeutic strategies.