Unveiling Sex-based Differences in Parkinson's Disease: A Comprehensive Meta-analysis of Transcriptomic Studies

In recent decades, increasing longevity (among other factors) has fostered a rise in Parkinsons disease (PD) incidence. Although not exhaustively studied in this devastating disease, the impact of sex represents a critical variable in PD as epidemiological and clinical features differ between males and females. To study sex bias in PD, we conducted a systematic review, tissue-specific meta-analyses of transcriptomic data from the frontal cortex (FC), striatum tissue (ST), and substantia nigra (SN), and a global meta-analysis of all 3 brain regions. We selected 7 PD studies that included sex information, analyzing 267 samples. The tissue-specific meta-analyses linked PD to the enhanced expression of MED31 in the female FC and the dysregulation of 237 genes in the SN. The global meta-analysis detected 15 genes with sex-differential patterns in PD, which participate in mitochondrial function, oxidative stress, neuronal degeneration, and cell death. Furthermore, functional analyses identified pathways, protein-protein interaction networks, and transcription factors that differed by sex. While male PD patients exhibited changes in oxidative stress based on metal ions, inflammation, and angiogenesis, female PD patients exhibited dysfunctions in mitochondrial and lysosomal activity, antigen processing and presentation functions, and glutamic and purine metabolism. Overall, we believe that our findings will provide new insight into the perspective of sex in PD, thereby underscoring the importance of including sex information in future PD studies.