Fig. 2.

Reduced expression of STING in aged macrophages albeit the cGAS-STING pathway was upregulated during infection. (A) Abundance of cytosolic mtDNA 8 h p.i. was measured in three biological replicates of hMdM with quantitative RT-PCR. After infection with IAV/PR8 hMdM show elevated levels of cytosolic mtDNA. Significance was evaluated with paired t-test (* p ≤ 0.05). (B) Whole cell extracts (WCE) and cytosolic fractions were analyzed by western blot using the indicated antibodies. (C) Heatmap with DEGs related to cytosolic DNA sensing pathways. Gene expression is presented over log2 fold change. The DEG of at least one condition per row had a log2 fold change > 1 with a significance of p ≤ 0.05. (D) KEGG-Enrichment pathway of cytosolic DNA sensing pathway comparing aged hMdM to young hMdM infected with IAV/PR8 24 h p.i. showing reduced expression of STING in aged hMdM. Red signals upregulation, green signal downregulation. (E) Gene expression of TMEM173 was shown as a bar plot. Significance was calculated with Kruskal-Wallis test (* p ≤ 0.05). (F) Concentration of cGAS and cGAMP were measured with ELISA in four biological replicates of hMdM 8 h and 24 h p.i. Significance was evaluated with paired t-test (* p ≤ 0.05)