Sex differences in Alzheimer's disease from single cell transcriptomics data analysis

Alzheimer’s disease (AD) is the leading cause of dementia. The clinical symptoms of AD begin with short-term memory impairment and gradually important cognitive and conductual functions are deteriorated, finally driving to death. By 2050, the number of AD patients is expected to growth to more than 50 millions which, in addition to the lack of disease-modifying treatments and precise and early diagnostic methods, highlights the interest of the investigation in this field. As sex differences in prevalence, severity and progression of AD and many other diseases have been reported, sex perspectives in biomedical research may lead for a better and faster understanding of diseases, being a fundamental step towards personalized medicine. We have explored the sex-related molecular differences in AD by integrative analysis of single cell transcriptomics studies from postmortem brain tissues. Single cell RNA sequencing (scRNA-seq) is a powerful approach to reveal the cellular heterogeneity masked in population-averaged detected gene expression in bulk RNA-seq. For this purpose, we have performed a systematic review following the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) that afforded the selection of three studies. We conducted a differential gene expression analysis by cell type across sex/disease groups of subjects for each study individually and then, we integrated all the results.