Genome-wide microarray analysis on choroid plexus of young and aged mice

Aging induces cognitive decline and Th2 cytokines have been found to promote neurogenesis and cognitive functions. ILC2 are potent producers of IL-5 and IL-13. The role of ILC2 in cognitive function in the context of aging has not been investigated. We report tissue resident ILC2 accumulate in the choroid plexus of the brain in aged mice. They are long-lived and can switch between cellular dormancy and proliferation in response to replication stress. ILC2 play a direct role in promoting the cognitive functions in aged mice, through producing IL-5. IL-5 has neuroprotective functions including neurogenesis and reducing pro-inflammatory functions of microglia in aged mice. We used microarrays to detail the global program of different gene expression between the choroid plexus of young (2-3 mos) and aged (20-22 mos) mice.