Fig. 2

The effects of the N-terminal truncation mutants of sTREM2 on microglial responses. A Schematic diagram of a series of N-terminal truncation mutants of sTREM2 fused with human IgG-Fc. B Silver staining analysis of the sTREM2 fragments purified from the conditioned media of transfected HEK293T cells. C, D Primary microglia were treated with 20 nM of Fc alone or the Fc-tagged sTREM2 fragments for 4 h. RNA was extracted, and the relative mRNA levels of IL-1β (C) and TNF (D) were determined by quantitative real-time PCR. β-Actin was used as an internal control (n = 3–5 per group, one-way ANOVA). E Microglia were treated with 20 nM Fc alone or the Fc-tagged sTREM2 fragments for 24 h after GM-CSF withdrawal. TUNEL was performed to analyze cellular apoptosis (n = 3, one-way ANOVA). F The binding affinity between oAβ_1–42 and either of Fc, the Fc-tagged sTREM2 fragment 41–81, 51–81, 1–157 at indicated concentrations were analyzed by solid-phase binding assay (n = 4, one-way ANOVA). G Dot blot of oAβ_1–42 binding to either of Fc, sTREM2 fragment 41–81, 51–81, 1–157. A PVDF membrane was spotted with each of the sTREM2 fragment and then incubated with 100 nM oAβ_1–42. Bound Aβ was detected by MOAB-2 antibody