Aging enhances release of exosomal cytokine mRNAs by A1-42-stimulated macrophages

Amyloid-1-42 (A) peptide effects on human models of central nervous system (CNS)-patrolling macrophages (Ms) and CD4 memory T-cells (CD4- Tms) were investigated to examine immune responses to A in Alzheimer's disease. A and lipopolysaccharide (LPS) elicited similar M cytokine and exosomal mRNA (ex-mRNA) responses. A- and LPS-stimulated Ms from 20 >65-yr-old subjects generated significantly more IL-1, TNF, and IL-6, but not IL-8 or IL-12, and significantly more ex-mRNAs for IL-6, TNF, and IL-12, but not for IL-8 or IL-1, than Ms from 20 matched 21- to 45-yr-old subjects. CD4-Tm generation of IL-2, IL-4, and IFN and, for young subjects, IL-10, but not IL-6, evoked by A was significantly lower than with anti-T-cell antigen receptor antibodies (Abs). Abs significantly increased all CD4-Tm ex-mRNAs, but only IL-2 and IL-6 ex-mRNAs were increased by A. There were no significant differences between cytokine and ex-mRNA responses of CD4-Tms from the old compared to the young subjects. M-derived serum exosomes from the old subjects had significantly higher IL-6 and IL-12 ex-mRNA levels than those from the young subjects, whereas there were no differences for CD4-Tm-derived serum exosomes. An A level relevant to neurodegeneration elicited broad M cytokine and exmRNA responses that were significantly greater in the old subjects, but only narrow and age-independent CD4-Tm responses.-Mitsuhashi, M., Taub, D. D., Kapogiannis, D., Eitan, E., Zukley, L., Mattson, M. P., Ferrucci, L., Schwartz, J. B., Goetzl, E. J. Aging enhances release of exosomal cytokine mRNAs by A1-42-stimulated macrophages.