Bacterial EVs were isolated from the sera as described previously [21 (link)22 (link)23 (link)]. Male Tg-APPswe/PS1dE9 mice were sacrificed at the age of 8 months and blood was collected from the hearts of sacrificed mice. Collected blood was centrifuged at 1,500 × g for 15 min at 4℃, and sera were separated, frozen and stored at −70℃ until use.
The sera were diluted 1 in 3 with 1x PBS (pH 7.4; ML008-01, Welgene Inc., Gyeongsan, Korea) and centrifuged at 10,000 × g for 1 min at 4℃. Then, the supernatants were collected and filtered through a 0.22-µm filter to remove bacteria and foreign particles. The separated bacterial EVs were boiled at 100℃ for 40 min. They were then centrifuged at 13,000 rpm for 30 min at 4℃, and the supernatants were collected. Bacterial DNA was extracted from the boiled EVs with a PowerSoil DNA Isolation Kit (MO BIO Laboratories Inc., Carlsbad, CA USA) in accordance with the manufacturer's instructions. The DNA from the EVs in each sample was quantified with a QIAxpert system (QIAGEN, Hilden, Germany).
The sera were diluted 1 in 3 with 1x PBS (pH 7.4; ML008-01, Welgene Inc., Gyeongsan, Korea) and centrifuged at 10,000 × g for 1 min at 4℃. Then, the supernatants were collected and filtered through a 0.22-µm filter to remove bacteria and foreign particles. The separated bacterial EVs were boiled at 100℃ for 40 min. They were then centrifuged at 13,000 rpm for 30 min at 4℃, and the supernatants were collected. Bacterial DNA was extracted from the boiled EVs with a PowerSoil DNA Isolation Kit (MO BIO Laboratories Inc., Carlsbad, CA USA) in accordance with the manufacturer's instructions. The DNA from the EVs in each sample was quantified with a QIAxpert system (QIAGEN, Hilden, Germany).
