TREM2 and Alzheimer disease: miR-34a is upregulated in the brain of AD patients (Table 1), and bioinformatics/transfected luciferase reporter assays show that miRNA-34a targets 299 nucleotides in the trem2-mRNA-3’UTR, leading to downregulation of triggering receptor expressed on myeloid cells 2 (TREM2).