Identification of Plasma Cell Subsets and Molecular Markers of Alzheimer’s Disease Based on Single-Cell Weighted Gene Co-Expression Network Analysis, Mendelian Randomization Analysis and Clinical Validation

Chao Xin,1,2 Hong-Wei Zhi,3 Da-Hua Wu,4 Peng-Li Ding,1 Zhong-Lin Wang,1,3 Ya-Han Wang4 1Shandong University of Traditional Chinese Medicine, Jinan, Shandong, People’s Republic of China; 2Affiliated Hospital of Shandong Academy of Traditional Chinese Medicine, Jinan, Shandong, People’s Republic of China; 3Shandong University of Traditional Chinese Medicine Affiliated Hospital, Jinan, Shandong, People’s Republic of China; 4Hunan Provincial Hospital of Integrated Traditional Chinese and Western Medicine, Changsha, Hunan, People’s Republic of ChinaCorrespondence: Zhong-Lin Wang, Affiliated Hospital of Shandong Academy of Traditional Chinese Medicine, Jingshi Road No. 16369, Lixia District, Jinan, Shandong, People’s Republic of China, Tel +86-0531-6861-6039, Email [email protected] Ya-Han Wang, Hunan Provincial Hospital of Integrated Traditional Chinese and Western Medicine, Lushan Road No. 58, Yuelu District, Changsha, Hunan, People’s Republic of China, Tel +86-15811105935, Email [email protected]: Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by gene expression alterations and immune dysregulation.Methods: In this study, we downloaded the GSE181279 single-cell dataset from the Gene Expression Omnibus (GEO) and applied bioinformatic analysis and clinical subject validation.Results: After quality control and harmony integration, we identified 21 cell subsets, including T cells, B cells, plasma cells, and macrophages. Plasma cells were significantly elevated in AD patients, and six plasma cell subtypes were associated with AD. High-dimensional weighted gene co-expression network analysis (hdWGCNA) revealed two AD-related modules. Mendelian randomization identified RGS1 as a key risk gene (p = 0.0123). Immune infiltration analysis showed RGS1 negatively correlated with macrophages and positively with tumor-infiltrating lymphocytes. Functional enrichment indicated that RGS1 is involved in JAK-STAT, NF-κB, and Wnt-β-catenin signaling pathways, suggesting a role in immune regulation and neuroinflammation. Furthermore, validation in AD patients confirmed that RGS1 expression levels were higher than in controls (p < 0.01).Discussion: This study identified the key gene RGS1 related to AD and explored multiple signaling pathways associated with it, which provided important clues for the research on AD-related inflammation, gut microbiota, stretch-gated ion channel, and the evaluation of AD therapeutic targets.Clinical Trial Registration Number: CTR20210477. Keywords: alzheimer’s disease, mendelian randomization, single-cell analysis, key genes, clinical validation