The role of signaling crosstalk of microglia in hippocampus on progression of ageing and Alzheimer's disease.

Based on single-cell sequencing of the hippocampi of 5× familiar Alzheimer's disease (5× FAD) and wild type mice at 2-, 12-, and 24-month of age, we found an increased percentage of microglia in aging and Alzheimer's disease (AD) mice. Blood brain barrier injury may also have contributed to this increase. Immune regulation by microglia plays a major role in the progression of aging and AD, according to the functions of 41 intersecting differentially expressed genes in microglia. Signaling crosstalk between C-C motif chemokine ligand (CCL) and major histocompatibility complex-1 bridges intercellular communication in the hippocampus during aging and AD. The amyloid precursor protein (APP) and colony stimulating factor (CSF) signals drive 5× FAD to deviate from aging track to AD occurrence among intercellular communication in hippocampus. Microglia are involved in the progression of aging and AD can be divided into 10 functional types. The strength of the interaction among microglial subtypes weakened with aging, and the CCL and CSF signaling pathways were the fundamental bridge of communication among microglial subtypes.

Qi-fu-yin attenuated cognitive disorders in 5xFAD mice of Alzheimer's disease animal model by regulating immunity.

Introduction: Cognitive impairment is the main symptom of Alzheimer's disease (AD). Accumulating evidence implicate that immunity plays an important role in AD. Here, we investigated the effect of Qi-fu-yin (QFY) on cognitive impairment and cytokine secretion of 5xFAD mice. Methods: We used 2.5-month-old 5xFAD transgenic mice for behavioral tests to observe the changes in cognitive function after QFY treatment. After the behavioral experiment, the whole brain, cortex and plasma of each mouse were collected for soluble Aß analysis, immunohistochemical experiment and cytokine analysis. Results: Here we found that the treatment of QFY ameliorated the ability of object recognition, passive avoidance responses and the ability of spatial learning and memory in 5xFAD mice. The deposits of ß1 - 42 and Aß1 - 40 were alleviated and the ration of Aß1 - 42/Aß1 - 40 was decrease in the plasma and brain of 5xFAD mice administrated with QFY. The administration of QFY promoted the secretion of anti-inflammatory cytokines, IL-5, IL-10 and G-CSF, and reduced the content of proinflammatory cytokines IFN-γ in plasma of 5xFAD mice. Notably, we found that the treatment of QFY decreased the concentration of CCL11 in the brain and plasma of 5xFAD mice. Conclusion: This suggested that QFY improved cognition and reduced Aß deposits in 5xFAD mice by regulating abnormal immunity in 5xFAD mice. QFY may be as a potential therapeutic agent for AD.