Animals

Young adult female C57BL/6J mice (8–10 weeks old) were obtained from the Animal Resources Centre Perth. Aged animals (C57BL6/J and DCX^DTR mice²⁸) between 18 and 20 months of age at the beginning of each experiment were obtained from aged mouse colonies maintained at the animal facility of the Queensland Brain Institute at The University of Queensland. Homozygous PF4 knockout mice were obtained from Anna Kowalska and have been described previously¹⁴. If not otherwise stated, the mice were group-housed on a 12 h light/dark cycle and had ad libitum access to food and water, with their housing temperature ranging from 18.5 to 24 °C and 40 to 60% humidity. Following perfusion of aged mice, a careful examination of organs was performed, leading to the exclusion of animals with indications of chronic inflammation, such as a greatly enlarged spleen, lymph nodes and liver, as well as tumour growth. All experiments were approved by The University of Queensland Animal Ethics Committee (2018/{"type":"entrez-nucleotide","attrs":{"text":"AE000549","term_id":"2313403","term_text":"AE000549"}}AE000549, 2021/{"type":"entrez-nucleotide","attrs":{"text":"AE000317","term_id":"1788605","term_text":"AE000317"}}AE000317, 2023/{"type":"entrez-nucleotide","attrs":{"text":"AE000013","term_id":"11379471","term_text":"AE000013"}}AE000013) and performed in accordance with the Australian Code of Practice for the Care and Use of Animals for Scientific Purposes or in accordance with institutional guidelines approved by the University of California San Francisco Institutional Animal Care and Use Committee (AN194088).