Revitalizing the Aging Brain by Activating Immune Cells

A study in the Journal of Experimental Medicine suggests activating a specific class of immune cell called group 2 innate lymphoid cells (ILC2s) could reduce age-related cognitive decline and counter age-related neurodegeneration, reports SciTechDaily . Analysis of the brains of young and old mice found ILC2s accrued with age in the choroid plexus, which produces cerebrospinal fluid and is near the hippocampus — an area that plays a critical role in learning and memory. Older mouse brains had as much as five times as many ILC2 cells as younger brains, and large concentrations of ILC2s also were observed in the choroid plexus of older humans. Activating ILC2s in older mouse brains by adding the cell signaling molecule IL-33 generated proteins that stimulated the formation and survival of neurons. ILC2s from older mice also were able to live longer and produce more ILC2 upon activation than ILC2s from younger mice. Treating old mice with IL-33 or injecting them with pre-activated ILC2s enhanced their cognitive performance. ILC2 activation also produced the signaling molecule IL-5, which in old mice boosted neuron formation in the hippocampus and reduced the amount of potentially damaging inflammation — and improved cognitive performance. "Targeting ILC2 cells in the aged brain may provide new avenues to combat these diseases in humans," said Albany Medical College's Kristen L. Zuloaga.