Loss of Neurogenesis with Age is in Part Mediated by Inflammatory Signaling in the Brain

The immune system is intimately involved in tissue function throughout the body, but particularly so in the brain. The immune system of the brain is distinct from that of the rest of the body, the two separated by the blood-brain barrier, and the immune cells of the brain participate in a range of activities necessary to the function of neurons, as well as the creation, destruction, and maintenance of synaptic connections between neurons. It isn't surprising to find links between immune aging, inflammatory signaling, and dysfunction of many systems in the brain. The focus in the commentary noted here is on age-related loss of neurogenesis, the creation of new neurons from neural stem cells, followed by their integration into existing neural circuits. Immune cells contribute to this loss of neural stem cell activity via their inflammatory signaling. Why neurogenesis is attenuated in elderly individuals is an intriguing question that has raised renewed interest. Mechanisms associated with declined neurogenesis in the aged brain have been attributed to inflammatory cytokines. More recently, a specific role for interferon-γ (IFN-γ) produced by CD8-expressing cytotoxic T cells has been implicated. These observations suggest a scenario in which neurogenesis, at least in part, is regulated by immune cells within the aging brain. This raises several interesting questions with regards to the characteristics of specific immune cells within the brain, the signals for their ex...
Source: Fight Aging! - Category: Research Authors: Tags: Daily News Source Type: blogs