5-HT	5-hydroxytryptamine (serotonin)
Aβ	Amyloid-beta
AD	Alzheimer’s disease
APOE4	Apolipoprotein E4
BBB	Blood–brain barrier
CNS	Central nervous system
CO	Carbon monoxide
COX-2	Cyclooxygenase-2
DEP	Diesel exhaust particles
DKK1	Dickkopf-related protein 1
Dvl3	Disheveled segment polarity protein 3
FABP4	Fatty acid binding protein 4
GSK-3β	Glycogen synthase kinase 3 beta
HFD	High-fat diet
HPA	Hypothalamic–pituitary–adrenal
IDE	Insulin-degrading enzyme
IL-1β	Interleukin-1 beta
IL-6	Interleukin-6
JAK	Janus kinase
JNK	c-Jun N-terminal kinase
KYN	Kynurenine
KYNA	Kynurenic acid
KO	Knockout
LPS	Lipopolysaccharide
MAPK	Mitogen-activated protein kinase
MyD88	Myeloid differentiation primary response 88
NO2	Nitrogen dioxide
NF-κB	Nuclear factor kappa B
PM	Particulate matter
PM2.5	Particulate matter ≤ 2.5 µm
PM10	Particulate matter ≤ 10 µm
ROS	Reactive oxygen species
SASP	Senescence-associated secretory phenotype
SFAs	Saturated fatty acids
SOCS3	Suppressor of cytokine signaling 3
Sox6	SRY-box transcription factor 6
SPMI	Serious and persistent mental illness
STAT	Signal transducer and activator of transcription
TLR4	Toll-like receptor 4
TNF-α	Tumor necrosis factor alpha
TRP	Tryptophan