Brucella Induces an Unfolded Protein Response via TcpB That Supports Intracellular Replication in Macrophages
Figure 10
The chemical chaperone TUDCA inhibits BiP and CHOP induction and Brucella replication.
A) RAW cells were pre-treated with 500 µg/mL TUDCA, and then infected with 100 MOI Brucella (B. mel) for 30 min., washed, and incubated 24 h prior to harvesting for RNA analysis by qPCR. Results were combined from 3–4 independent experiments by normalization to B. melitensis induced UPR gene expression ( = 100%), *p≤0.04 and p = 0.00003 vs. B. melitensis infection and NS vs. uninfected. For XBP1s and ERdj4, N = 2 independent experiments. B) RAW cells were not treated (black circles) or pre-treated with TUDCA (gray squares), infected as in (A), and lysed at different times following infection. CFU (colony forming units) were determined by transfer to dilution plates. *P≤0.04. Similar results were obtained with 10 MOI Brucella (not shown). Results are representative of 6 independent experiments. C) D17 osteosarcoma cells were untreated (left) or pre-treated with 500 µg/mL TUDCA (right), infected with Brucella-YFP (green) for 24 h, fixed, and stained with anti-calreticulin (red).