Abstract Background As an important interface between the peripheral environment and the central nervous system, the gut microbiota varies greatly between patients or animals with Alzheimer’s disease (AD) and their respective non-AD counterparts; however, it remains unexplored whether the apolipoprotein E (APOE) genotype, age, and sex may interactively influence the characteristics of gut microbiota in AD animals. Methods APOE genotype, age, and sex were enrolled as independent variables, with genotype distinguished into APOE3 and APOE4, age into 3 and 10 months, and sex into female and male. The composition, structure, and potential functions of gut microbiota were systematically analyzed by 16S rRNA gene amplicon sequencing to evaluate the individual and interactive effects of APOE genotype, age and sex. Results Significant interactions were observed among APOE genotypes, ages, and sexes, with different factor combinations exhibiting distinct effect on microbiotic composition and functional potential. APOE genotype exerted the most significant influence on gut microbiota, followed by age and sex with a relatively minor effect, highlighting the dominant role of host genetic background. Functional prediction analysis indicated that the functional profiles were mainly concentrated in basic metabolic pathways, including the biosynthesis of secondary metabolites and amino acids, and carbon metabolism. Conclusion APOE genotype, age, and sex are jointly associated with the structure and potential function of the gut microbiota in AD model mice. These findings provide a perspective of multi-factor interaction into the alterations in gut microbiota in AD and offer new microecological evidence for understanding APOE4-related AD susceptibility, as well as a conceptual basis for future stratified microecological intervention studies.
Mi et al. (Sun,) studied this question.