Abstract
Background/Objectives: Neurodegenerative diseases (NDs) such as Alzheimer's (AD), Parkinson's (PD), Huntington's (HD), and Amyotrophic Lateral Sclerosis (ALS) are clinically distinct but share overlapping molecular mechanisms. Methods: To identify conserved systemic signatures, we analyzed blood RNA-Seq datasets using Weighted Gene Co-Expression Network Analysis (WGCNA), differential expression, pathway enrichment, and miRNA-mRNA network mapping. Results: Two modules, the red and turquoise, showed strong preservation across diseases. The red module was enriched for cytoskeletal and metabolic regulation, while the turquoise module involved immune, stress-response, and proteostatic pathways. Discussion: Key hub genes, such as HMGCR, ACTR2, MYD88, PTEN, EP300, and regulatory miRNAs like miR-29, miR-132, and miR-146a, formed interconnected networks reflecting shared molecular vulnerabilities. The absence of classical heat shock proteins in preserved blood modules highlights tissue-specific expression differences between blood and neural systems. Several hub genes overlap with known pharmacological targets, suggesting potential in translational relevance. Conclusions: Together, these findings reveal conserved blood-based transcriptional modules that suggest parallel central neurodegenerative processes and may support future biomarker development and possible therapeutic exploration.