Immune cells released from bone marrow in the skull in response to chronic stress and adversity could play a key role in symptoms of depression and anxiety, say researchers. The discovery – found in a study in mice – sheds light on the role that inflammation can play in mood disorders and could help in the search for new treatments, in particular for those individuals for whom current treatments are ineffective.

Led by researchers at the Center for Infection and Immunity (CII) at Columbia University Mailman School of Public Health with a multicenter team of leading ME/CFS researchers, the new study reveals molecular-level details into the syndrome’s lasting effects on inflammation and immune response that could inform the development of targeted therapeutic interventions to reduce symptoms of ME/CFS and other postinfectious syndromes such as post-treatment Lyme disease and Long COVID.

The gut contains the largest collection of immune cells in the body. New research at the Buck Institute shows that some of those immune cells travel along the brain/gut axis in a mouse model of Alzheimer’s disease (AD) providing a potential new therapeutic pathway for the memory-robbing malady. The research, published in the August29, 2025 issue of Cell Reports, also shows that feeding the mice a high fiber diet reduces AD-related frailty, including tremor.