Microglial hyperreactivity evolved to immunosuppression in the hippocampus of a mouse model of accelerated aging and Alzheimer’s Disease traits

Neuroinflammation is a risk factor for Alzheimer’s disease (AD). We sought to study the glial derangement in AD using diverse experimental models and human brain tissue. Besides classical pro-inflammatory cytokines, we analyzed chitinase 3 like 1 (CHI3L1 or YKL40) and triggering receptor expressed on myeloid cells 2 (TREM2) that are increasingly being associated with astrogliosis and microgliosis in AD, respectively. The SAMP8 mouse model of accelerated aging and AD traits showed elevated pro-inflammatory cytokines and activated microglia phenotype. Furthermore, 6-month-old SAMP8 showed an exacerbated inflammatory response to peripheral lipopolysaccharide in the hippocampus and null responsiveness at the advanced age (for this strain) of 12 months.This research was funded by Spanish MINECO and European Regional Development Fund, grant number SAF2016- 77703; Spanish MCINN, grant number PID2019-106285RB; Catalan Autonomous Government AGAUR, grant number 2017-SGR-106; Competitiveness Operational Programme 2014-2020, C-Reactive protein therapy for stroke-associated dementia, ID P_37_674, MySMIS code: 103432, contract 51/05.09.2016; and the CERCA Programme/Generalitat de Catalunya. RCo was supported by a post-doctoral research contract of the Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP), Instituto de Salud Carlos III, Madrid, Spain. AL (PERIS SLT008/18/00061) received funding from Departament de Salut de la Generalitat de Catalunya. We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI)