The Ct value of target gene in each sample was normalized to that of reference gene, giving ΔCt. Then the ΔCt values of treated macrophages were compared with Fluorouracil solubility dmso that of untreated ones, giving ΔΔCt. The logarithm was used to calculate the relative expression of the target gene.
The macrophages were pre-treated with recombinant mouse IL-17A for 24 hr before BCG infection at a multiplicity of infection of 1. After 3 hr of BCG infection, infected macrophages were washed with PBS and replenished with fresh medium containing 1 μg/ml actinomycin D (Sigma-Aldrich). At the indicated time-points, total RNA from infected macrophages was extracted by using TRIzol reagent and reverse transcribed to complementary DNA. The relative expression level of iNOS mRNA was determined by qPCR. After 2 hr (phagocytosis assay) or 48 hr (bacteria survival assay) of BCG infection, the intracellular bacteria were recovered based on the methods described previously.[21] Briefly, the infected macrophages were washed thrice with PBS. The cells were then lysed by lysis buffer (PBS, 0·5% Triton X-100) to recover intracellular bacteria. The cell lysates were appropriately diluted in EGFR signaling pathway PBS containing 0·05% Tween-80 and were plated onto Middlebrook 7H10 agar (BD Biosciences). The agar plates were incubated at 37° supplemented with 5% CO2. Colony-forming units (CFU) were enumerated after 3 weeks of incubation. To collect
whole cell lysates, the macrophages were washed once with PBS and lysed by ice-cold whole cell lysis buffer (10 mm Tris–HCl, pH 7·4, 50 mm NaCl, 50 mm NaF, 10 mm β-glycerophosphate, 0·1 mm EDTA, 10% glycerol, 1% Triton X-100, 2 μg/ml aprotinin, 1 mm sodium orthovanadate, 2 μg/ml leupeptin, 2 μg/ml pepstatin and 1 mm PMSF). Soluble proteins were harvested after centrifugation at 16 000 g for 5 min. The protein concentrations in the whole cell lysates were quantified by bicinchoninic acid (BCA) protein assay kit (Thermo Fisher Scientific, Waltham, MA) according to the manufacturer’s instructions. The extraction of cytoplasmic proteins and Staurosporine in vitro nuclear proteins was based on the methods described previously.[22]
Briefly, the macrophages were washed twice with cold 1 × PBS, followed by incubation with buffer A (10 mm HEPES, pH 7·9, 10 mm KCl, 0·1 mm EDTA, 0·1 mm EGTA, 1 mm dithiothreitol, 2 μg/ml aprotinin, 1 mm sodium orthovanadate, 2 μg/ml leupeptin, 2 μg/ml pepstatin and 1 mm PMSF) on ice for 15 min. The cells were lysed by adding nonidet P-40 to a final concentration of 0·625%. The lysates were centrifuged at 16 000 g for 5 min at 4°. The supernatant containing cytoplasmic proteins was harvested. The pellets were washed once with buffer A and then lysed in buffer C (20 mm HEPES, pH 7·9, 0·4 mm NaCl, 50 mm NaF, 1 mm EDTA, 0·1 mm EGTA, 1 mm dithiothreitol, 2 μg/ml aprotinin, 1 mm sodium orthovanadate, 2 μg/ml leupeptin, 2 μg/ml pepstatin and 1 mm PMSF). The lysates were centrifuged at 16 000 g for 5 min at 4°.