Abstract
Cystathionine β-synthase (CBS)-deficient patients are prone to vascular thrombosis. In contrast, Cbs-/- mice show no abnormalities in blood coagulation. To identify molecular basis underlying these disparately different thrombotic phenotypes, we analyzed plasma proteomes of Cbs-/- vs. Cbs+/+ mice (8-month-old, 12/group, sex-matched) and CBS-/- vs. CBS+/+ humans (37 ± 7-year-old, 10-14/group, sex-matched) using label-free mass spectrometry. We identified 117 and 41 differentiating plasma proteins in Cbs-/- mice and CBS-/- humans, respectively. Twenty-one proteins were shared between CBS-/- humans and Cbs-/- mice, with sixteen changed in the opposite direction. Proteins involved in blood coagulation and complement/coagulation cascades represented a greater fraction of the differentiating proteins in CBS-/- patients (51%) than in Cbs-/- mice (21%). Top canonical pathways, identified by Ingenuity Pathways Analysis, such as LXR/RXR, FXR/RXR activation (- log[P-value] = 30-31) and atherosclerosis signaling (- log[P-value] = 10-11) were similarly affected in Cbs-/- mice and CBS-/- humans. The Coagulation System was affected stronger in CBS-/- humans than in Cbs-/- mice (- log[P-value] = 15 vs. 10, respectively) while acute phase response and complement system were affected stronger in Cbs-/- mice (- log[P-value] = 33 and 22, respectively) than in humans (- log[P-value] = 22 and 6, respectively). Other pathways, including IL-7 signaling and B cell development were affected only in Cbs-/- mice. Taken together, our findings suggest that differences in these processes, in particular in the Coagulation System, could account for the thrombotic phenotype in CBS-/- patients and the absence of thrombosis in Cbs-/- mice. Overall, our findings suggest that Cbs-/- mice have a better adaptive response to protect from prothrombotic effects of hyperhomocysteinemia than CBS-/- humans.