Bortezomib reduced viral load and signs of dengue pathology in C57BL/6 mice.

<p>WT mice infected intraperitonealy with DENV2 were treated with bortezomib 6 hpi and analyzed at 24, 48 and 72 hpi for further analysis. (A) For quantification of NS3+ cells, the mean cell count in 20 alternate microscopic high-power fields (x400) was measured. Quantification was done only in the red pulp of spleen. Bortezomib treated mice showed significantly reduced number of DENV infected cells in the red pulp of the spleen at 24 and 48 hpi compared to vehicle control. Mean ± SEM. N = 4–5. Student’s t test, **p<0.01. (B) Representative serial sections from spleen of each group of mice stained with anti-DENV NS3 antibody at 24, 48 and 72 hpi. Multiple sections of each tissue were examined for staining (60x magnification). The inset is a representation of the spleen from mock infected mice without (top panel) or with (bottom panel) bortezomib treatment. The top panel shows DENV-infected spleen without bortezomib treatment 24, 48 and 72 hpi. The bottom panel shows DENV-infected spleen with bortezomib treatment 24, 48 and 72 hpi. Positive staining for NS3 is brown while hematoxylin counterstaining is blue. Bortezomib treated mice also showed significantly reduced number of DENV infected cells in the red pulp of the spleen at 24 and 48 hpi compared to vehicle control. (C) RNA copy number in the spleen was reduced in bortezomib treated mice compared to vehicle control at 48 hpi. Mean ± SEM. N = 4–5. Student’s t test, *p<0.05. (D-E) The vehicle control experienced a drop in platelet count over the first 48 hours of infection before recovering by day 3, and experienced a significant rise in hematocrit values that peaked 24 hpi. On the other hand, no significant changes were observed for the platelet count 24–72 hpi, and hematocrit levels 0–72 hpi in mice after bortezomib treatment, suggesting the efficiency of bortezomib in alleviating disease symptoms. Mean ± SEM. N = 4–5. Student’s t test, *p<0.05, ****p<0.0001. (F-G) DENV2-infected vehicle control displayed an increased systemic level of MCPT1, indicative of mast cell activation, in mouse serum and spleen when compared to bortezomib treated mice at all time-points. (H) Levels of TNF-α were decreased in bortezomib treated mice 24 hpi when compared to the vehicle control. Mean ± SEM. N = 4–5. Student’s t test, *p<0.05.