M-CSFR (CD115) knockdown reduces LPS-induced splenomegaly. (A) In vitro screening for siRNA inhibitors of CD115 mRNA (n = 3 per group). (B) Concentration dependence of the six best siRNAs against CD115 mRNA (n = 3). (C) Experimental design. LPS-treated mice were injected with siRNA against CD115 (siCD115) or control siRNA with an irrelevant sequence (siCON), or left uninjected. (D) CD115 mRNA levels in FACS-isolated monocytes/macrophages (n = 4–6). (E) CD115 expression on monocytes/macrophages by flow cytometry (n = 6–8 per group). (F) Body (n = 3–5) and (G) spleen weight of naive and treated mice (n = 3–10). (H) Total splenocyte count of naive and treated mice (n = 4–9 per group). (I) Serum IFN-γ levels measured by ELISA (n = 3–8). Flow cytometric plots (J) and quantification (K) of monocytes and Ly-6chigh monocytes in blood after siRNA treatment (n = 3–5). Data were pooled from 2–5 independent experiments and are mean ± SEM. Significance was determined by Mann-Whitney test or one-way ANOVA. **, P < 0.01; ***, P < 0.001.
