Changes in Expression Profiles Revealed by Transcriptomic Analysis in Peripheral Blood Mononuclear Cells of Alzheimer’s Disease Patients

Article type: Research Article

Authors: Leandro, Giovana Silva^a | Evangelista, Adriane Feijó^b | Lobo, Romulo Rebouças^c | Xavier, Danilo Jordão^a | Moriguti, Julio César^c | Sakamoto-Hojo, Elza Tiemi^{a; d; *}

Affiliations: [a] Department of Genetics, Ribeirão Preto Medical School, University of São Paulo – USP, Ribeirão Preto, SP, Brazil | [b] Molecular Oncology Research Center, Barretos Cancer Hospital, Barretos, SP, Brazil | [c] Department of Internal Medicine, Ribeirão Preto Medical School, University of São Paulo – USP, Ribeirão Preto, SP, Brazil | [d] Department of Biology, Faculty of Philosophy, Sciences and Letters at Ribeirão Preto, University of São Paulo – USP, Ribeirão Preto, SP, Brazil

Correspondence: [*] Correspondence to: Elza Tiemi Sakamoto Hojo, Department of Biology, Faculty of Philosophy, Sciences and Letters at Ribeirão Preto – USP, Avenida Bandeirantes 3900, 14040-901 Ribeirão Preto, SP, Brazil. Tel.: +55 16 3315 3827; E-mail: [email protected].

Abstract: Alzheimer’s disease (AD) is an age-related neurodegenerative pathology associated with accumulation of DNA damage. Inflammation and cell cycle alterations seem to be implicated in the pathogenesis of AD, although the molecular mechanisms have not been thoroughly elucidated to date. The aim of the present study was to evaluate whether peripheral blood mononuclear cells (PBMCs) of AD patients display alterations in gene expression profiles, focusing on finding markers that might improve the diagnosis of AD. Blood samples were collected from 22 AD patients and 13 healthy individuals to perform genome-wide mRNA expression. We found 593 differentially expressed genes in AD compared to controls, from which 428 were upregulated, and 165 were downregulated. By performing a gene set enrichment analysis, we observed pathways involved in inflammation, DNA damage response, cell cycle, and neuronal processes. Moreover, functional annotation analyses indicated that differentially expressed genes are strongly related to pathways associated with the cell cycle and the immune system. The results were compared with those of an independent study on hippocampus samples, and a number of genes in common between both studies were identified as potential peripheral biomarkers for AD, including DUSP1, FOS, SLC7A2, RGS1, GFAP, CCL2, ANGPTL4, and SSPN. Taken together, our results demonstrate that PBMCs of AD patients do present alterations in gene expression profiles, and these results are comparable to those previously reported in the literature for AD neurons, supporting the hypothesis that blood peripheral mononuclear cells express molecular changes that occur in the neurons of AD patients.

Keywords: Alzheimer’s disease, gene expression profiles, neurodegenerative disorders, peripheral blood cells

DOI: 10.3233/JAD-170205

Journal: Journal of Alzheimer's Disease, vol. 66, no. 4, pp. 1483-1495, 2018