TREM2 regulates the expression of ADAM17 and CD163.

(A) PAMs were transfected with siNC or siTREM2-1 for 24 h, and cells were collected. The protein levels of CD163 and ADAM17 are shown, as detected by western blot. GAPDH is shown as an internal control. (B) PAMs were transfected with siNC or siTREM2-1 for 12 h and infected with PRRSV (MOI = 1) for an additional 24 h. The CD163, ADAM17 and PRRSV N protein expression is shown, as measured by western blot. GAPDH is shown as an internal control. (C and D) PAMs were transfected with siNC or siTREM2-1 for 24 h, and then mock-infected or infected with PRRSV (MOI = 1) for 24 h. Expression of ADAM17 (C) and CD163 (D) is shown, as measured using qRT-PCR. (E and F) Immunofluorescence analysis is shown to detect the expression of ADAM17 (E) and CD163 (F) after down-regulating TREM2 expression (Bar, 200 μm). (G) Representative histograms for flow cytometry analysis of cell surface CD163 immunostaining for PAMs with the indicated conditions. (H) Corresponding positive cell ratio of cell surface CD163 based on analysis conditions in G. (I) PAMs with TREM2 knockdown were infected with PRRSV (MOI = 1) for the indicated periods. Cells were collected and protein levels of CD163, ADAM17, TREM2, and PRRSV N are shown using western blot analysis. GAPDH is shown as an internal control. (J—L) PAMs with TREM2 knockdown were infected with PRRSV (MOI = 1) in the presence or absence of R406 (5 μM) (J), Wortmannin (1 μM) (K) or BAY11-7082 (10 μM) (L) and western blots are shown to detect protein levels of ADAM17 and CD163. GAPDH is shown as an internal control. Data are representative of the results of three independent experiments (mean ± SE). Significant differences compared to the control group are denoted by * (P < .05), ** (P < .01) and *** (P < .001).