Studies on the mechanism of complement protein C4 in the regulation of aging [I]

Learning and memory capability always decline with age in healthy people, and synapse loss may be an important factor contributing to this reduction. The complement pathway plays a crucial role in synaptic pruning during normal brain development, and the abnormal activation of the classical complement cascade is involved in the pathogenesis of certain neurological disorders. However, none of the past studies elucidated the effects of complement proteins in the aging of the nervous system. Here, we performed transcriptome sequencing in multiple tissues of mice at different ages in an attempt to find important regulators during aging. Our results show that the expression of complement protein C4 in the mouse brain increases with aging. In addition, we constructed different neuronal aging models for transcriptome analysis to identify the regulatory pathways upstream of complement C4, and explored the possible mechanism of complement C4 involved in synapse pruning by co-culture or immunofluorescence methods. This further demonstrates that complement C4 is a potential marker of aging. These findings suggest that NF-κB signaling pathway may contribute to age dependent complement C4 increase, which in turn affect learning and memory function via neuronal synaptic pruning regulation. To investigate the mechanism of aging, we selected the cortex, hippocampus, kidney of 2m ,10m and 18m C57BL/6 mice, totally 9 mice for mRNA-Sequencing. We descript the universal functional characteristics and tissue-specific changes that occur during aging with various analysis strategies.