MAPT and Alzheimer disease: There is also experimental evidence that PM2.5 exposure can lead to early Alzheimer's disease (AD)-related pathology in transgenic AD mice, leading to AD-related molecular and cellular changes, such as mitochondrial dysfunction, synaptic defects, axonal growth impairment, nerve cell death, glial cell activation, neuroinflammation and neurovascular dysfunction, and increased levels of amyloid β (Aβ) and tau phosphorylation.