Choroid plexus sex differences in secretory signalling and immune compartments

The choroid plexus (ChP)-cerebrospinal fluid (CSF) axis is emerging as a key regulator of the brain environment. The ChP is a multi-functional structure, which forms the blood-CSF barrier, and acts as a sensor of inputs from the periphery and the brain, dynamically responding by modulating its secretome into the CSF. However, sex differences in the ChP have been little explored. Molecular profiling of the adult mouse ChP at the transcriptomic and proteomic levels revealed sex differences across multiple cell types, with immune signatures enriched in females. Interestingly, border associated macrophages showed distinct sex differences in the stromal and epiplexus compartments. We further uncovered sex differences in ChP secretory signalling, with functional differences between males and females. Finally, the human LVChP showed largely similar sex differences. Together, our findings highlight that sex differences may play an important role in ChP function in both health and disease.