Figure 4. Myeloid ablation of Malat1 (Malat1 mye^–/–) attenuates LPS-induced ALI.

(A) Alveolar macrophages were harvested from BALFs of Malat1^fl/fl and Malat1 mye^–/– mice. Levels of Malat1 in the cells were determined by real-time PCR. n = 6 each for Malat1^fl/fl and Malat1 mye^–/– mice; mean ± SE. (B and C) Malat1^fl/fl and Malat1 mye^–/– mice were i.t. instilled with 50 μl saline or 5 mg/kg LPS in 50 μl saline. Forty-eight hours after administration, mice were sacrificed and lung homogenates prepared. Levels of the indicated proinflammatory cytokines were determined by ELISA. n = 3, 6, 5, 6 mice for each group; mean ± SE. (D–F) Experiments were performed as in B and C. BALF levels of the indicated proinflammatory cytokines were determined by ELISA. n = 4, 6, 3, 6 mice for each group; mean ± SE. (G) Experiments were performed as in B and C. Levels of lung MPO were determined by ELISA. n = 3, 6, 5, 5 mice for each group; mean ± SE. (H) Experiments were performed as in B and C. H&E staining was performed. Original magnification, ×10. Scale bars: 200 μm. (I) Experiments were performed as in B and C. Twenty-four hours after administration, alveolar macrophages were harvested and mRNA levels of the indicated genes determined by real-time PCR. ● Malat1^fl/fl saline, ■ Malat1^fl/fl LPS, ▲ Malat1 mye^–/– saline, ▼ Malat1 mye^–/– LPS; n = 6, 4, 6, 4 mice for each group; mean ± SE. (J) Experiments were performed as in B and C. Twenty-four hours after administration, alveolar macrophages were harvested and mRNA levels of Clec16a determined. n = 4, 4 mice for each group; mean ± SE. *P < 0.05; **P < 0.01; ***P < 0.001 by 1-way ANOVA with Bonferroni’s post hoc test (B–I) or 2-tailed Student’s t test (J).