HRG attenuates RNA- and DNA-induced thrombin generation and clotting. (A-D) Thrombin generation in plasma from wild-type, HRG^+/−, and HRG^−/− mice containing 30 μM PCPS was triggered with RNA (16 μg/mL) or DNA (20 μg/mL) and 15 mM CaCl₂. Thrombin generated was quantified by monitoring hydrolysis of Z-Gly-Gly-Arg-AMC. Experiments were performed 3 times in duplicate. *P < .05, **P < .005 for thrombin generation initiated with DNA; ^##P < .005 for thrombin initiated with RNA, compared with wild-type plasma. (E-F) Clotting was initiated in plasma from wild-type (black bars) or HRG^−/− (gray bars) mice containing human HRG (0-3 μM) by addition of 30 μg/mL of DNA (E) or RNA (F) and 8.3 mM CaCl₂. Absorbance was monitored and the clot time was calculated as the time to achieve half maximum absorbance. Bars reflect the mean of 3 experiments, each performed in duplicate, and the lines above the bars reflect the standard deviation (SD). *P < .05 and **P < .005 compared with HRG^−/− plasma without added HRG; data were analyzed using Student t tests.