## 4 Results
### miRNA Pathway and Gene Ontology (GO) Analysis
\begin{table}
\begin{tabular}{l l l} \hline \hline \multicolumn{1}{c}{**Gene**} & \multicolumn{2}{c}{**Roles and Functions as Related to AD**} \\ \hline \multirow{4}{*}{**Nicastrin (NCSTN)**} & \(\bullet\) & Nicastrin is one of the subunits of \(\gamma\)-secretase that plays an important role in the amyloidogenic pathways of AD pathogenesis [53]. \\  & \(\bullet\) & The inactivation of _NCSSTN_ restricts \(A\beta\) production and subsequently inhibits neurodegeneration [53; 54]. \\ \hline \multirow{2}{*}{**Glutamate Ionotropic Receptor NMDA Type**} & \(\bullet\) & Expresses in the brain regions that are predominantly affected in AD [55]. \\  & \(\bullet\) & Involved in synaptic functioning, where its dysfunction leads to neuronal damage and cognitive impairment [55]. \\ \hline \multirow{4}{*}{**Eukaryotic translation initiation factor 2**} & \(\bullet\) & Encodes for PERK protein, which is involved in cognitive activities such as learning and memory [56]. \\  & \(\bullet\) & Overexpression of _EIF2 AK3_ induces tau phosphorylation and promotes amyloidogenesis [56]. \\  & \(\bullet\) & Interacts with the strongest genetic factor of AD, APOE4 [56; 57]. \\ \hline \multirow{2}{*}{**NADH:ubiquinone oxidoreductase subunit**} & \(\bullet\) & An OXPHOS gene [46]. \\  & \(\bullet\) & Involved in the oxidative phosphorylation pathway in AD [58]. \\ \hline \multirow{2}{*}{**NADH:ubiquinone oxidoreductase subunit**} & \(\bullet\) & An OXPHOS gene [46]. \\  & \(\bullet\) & Involved in mitochondrial failure, leading to \(A\beta\) accumulation [59]. \\ \hline \multirow{4}{*}{**Mitogen-activated protein kinase 1 (MAPKKI)**} & \(\bullet\) & Most prevalent genetic variant of AD [59; 60]. \\  & \(\bullet\) & Encodes protein presenilin 1, which is one of the subunits of \(\gamma\)-secretase that plays an important role in the amyloidogenic pathway of AD pathogenesis [60; 61]. \\  & \(\bullet\) & exacerbates the production of \(A\beta\) in AD pathogenesis [61]. \\ \hline \multirow{4}{*}{**Mitogen-activated protein kinase 1 (MAPKKI)**} & \(\bullet\) & Takes part in cellular signal transduction [62]. \\  & \(\bullet\) & \(A\beta\) induces the elevation of _MAPKKI_ expression, elevates tau phosphorylation, exacerbates the amyloidogenic pathway, and aggravates AD development [62; 63]. \\ \hline \multirow{2}{*}{**NADH:ubiquinone oxidoreductase subunit**} & \(\bullet\) & An OXPHOS gene [46; 64]. \\  & \(\bullet\) & Involved in mitochondrial energy metabolism; however, its main function remains unknown [64; 65]. \\ \hline \multirow{4}{*}{**Ryanodine receptor 3 (RYR3)**} & \(\bullet\) & Releases stored calcium ions into the extracellular space [66]. \\  & \(\bullet\) & The deposition of \(A\beta\) causes the increase of _RYR3_ expression [66]. \\  & \(\bullet\) & The upregulation of _RYR3_ may form a protection for the neurons and against the impact of \(A\beta\) in the late stage of AD [67; 68]. \\ \hline \multirow{4}{*}{\(\beta\)-secretase cleaving enzyme 1 (BACEI)} & \(\bullet\) & Responsible for \(\beta\)-secretase activity in the amyloidogenic pathway, which initiates the generation of \(A\beta\)[69]. \\  & \(\bullet\) & Shows high expression in AD patients as compared to normal controls, including in the plasma [70]. \\  & \(\bullet\) & The inhibition of _BACEI_ serves as the target for the study of AD drug candidates [71]. \\ \hline \multirow{4}{*}{**Cytochrome c oxidase subunit 4I1 (COX4 II)**} & \(\bullet\) & Involved in the mitochondrion electron transport chain, a crucial mechanism in cellular metabolism and the electron transport chain [72]. \\  & \(\bullet\) & The cleavage of APOE\(\epsilon\)4 inhibits the _COX_ gene, leading to mitochondrial dysfunction [73]. \\  & \(\bullet\) & _COX4 II_ showed significant downregulation in AD patients [72]. \\ \hline \hline \end{tabular}
\end{table} 
Table 5: _Cont._Defects in oxidative phosphorylation, mitochondrial mechanisms, and calcium signalling are interconnected in a cascade sequence and ultimately lead to neurodegeneration in AD.