Peripheral TREM2 mRNA levels in early and late-onset Alzheimer disease’s patients

• DOI: 10.1007/s11033-020-05661-7
• Publication Date: 2020-07-17T17:08:10Z
• Authors: Gamze Guven; Basar Bilgic; Bedia Samanci; Hakan Gurvit; Hasmet Hanagasi; Cagla Donmez; Rukiye Aslan; Ebba Lohmann; Nihan Erginel-Una...
• Keywords: Adult; Male; Genotype; blood [Receptors, Immunologic]; Apolipoprotein E4; genetics [Alzheimer Disease]; pathology [Alzheimer Disease]; genetics [RNA, Messenger]; 03 medical and health sciences; blood [Alzheimer Disease]; 0302 clinical medicine; genetics [Membrane Glycoproteins]; Alzheimer Disease; ddc:570; blood [Membrane Glycoproteins]; genetics [Receptors, Immunologic]; Humans; blood [RNA, Messenger]; RNA, Messenger; Age of Onset; Receptors, Immunologic; genetics [Apolipoprotein E4]; Aged; Aged, 80 and over; blood [Biomarkers]; Membrane Glycoproteins; Middle Aged; 3. Good health; Case-Control Studies; Female; Biomarkers

'Triggering receptor expressed on myeloid cells 2' (TREM2) gene is involved in Alzheimer's disease (AD) and TREM2 mRNA expression is known to be increased in the peripheral blood cells of AD patients. In this study, we examined the expression levels of TREM2 mRNA in peripheral leukocytes of early and late-onset AD patients. We have also investigated the effect of the presence of APOE ε4 allele on TREM2 expression. TREM2 mRNA expression was analyzed in 30 early-onset AD (EOAD) patients, 38 late-onset AD (LOAD) patients, and in their age-matched controls by using quantitative real-time polymerase chain reaction. TREM2 levels in LOAD patients were higher than EOAD. Also, in elderly controls significantly higher TREM2 levels were found compared with young controls. Moreover, APOE ε4 carriers in LOAD patients exhibited significantly higher TREM2 expression levels than APOE ε4 non-carriers and elderly controls. Also, correlation analysis showed that TREM2 mRNA expression was increased by age. The differential expression of TREM2 mRNA levels between EOAD and LOAD patients might be independent of the AD disease status and results from an age-related increase in TREM2 expression. In LOAD patients, increased age and the presence of APOE ε4 allele further increase TREM2 expression. Taken together, we can suggest that age is a factor that increases TREM2 expression, and TREM2 and APOE ε4 may interact together in the pathogenesis of LOAD.