A thorough analysis of the molecular mechanisms underlying the protein changes in the human cerebral cortex affected by Alzheimer's disease

Alzheimer's disease (AD) is a diverse condition with an intricate pathobiology. Cortex plays a role in regulating body movements, executive function, and cognitive control and serves as a hub for replaying information in the auditory and visual systems. There is a correlation between the rate of change in cortical thickness, cerebrospinal fluid, plasma neurofilament light levels, and cognitive function. However, cognitive impairment is typically closely associated with the decline of neurons and synapses in different regions of the cortex. Thus, more endeavor has been made to understand the pathophysiology of AD involved in the perturbation in the cortex, but fundamental molecular mechanisms related to protein changes that happen in the cortex region remain unanswered. We aimed to investigate the molecular mechanisms implicated in the etiology of Alzheimer's disease in eight distinct regions of the human cortex. Using mass-spectrometry-based proteomic data from 29 published studies until March 15, 2022, hub proteins and protein-protein interactions, signaling pathways, miRNAs, and transcription factors were analyzed. Nine proteins—GFAP, APP, HSPB1, CD44, CLU, RPH3A, VGF, CAPG, and CORO1A—were prevalent in all of the studies. APP, ALB, and HSP90AA1 were found in 4/8, 3/8, and 3/8 regions of the cortex, respectively. Although the putative proteins obtained from various areas of cortex differed, important molecular pathways were identified, including impaired neuronal systems, mitochondrial and ribosomal functions, activated innate immune systems and microglia, and activated NMDA receptors. The primary microRNA (hsa-miR-16-5p) and transcription factor (CREB3L3) were the main factors responsible for the etiology of AD related to protein changes. Focusing on the proteins, miRNAs, transcription factors, and molecular processes in the cortex plays a crucial role in managing AD.