Benzene metabolites increase vascular permeability by activating heat shock proteins and Rho GTPases.

Benzene is a ubiquitous environmental and occupational pollutant abundant in household products, petrochemicals, and cigarette smoke. It is also a well-known carcinogen and hematopoietic toxin. Population-based studies indicate an increased risk of heart failure in subjects exposed to inhaled benzene, which coincides with the infiltration of immune cells into the myocardium. However, the mechanisms of benzene-induced cardiovascular disease remain unknown. Our data suggests that benzene metabolites trans,trans-muconaldehyde (MA), and hydroquinone (HQ) propagate endothelial activation and apoptosis analyzed by endothelial-specific microparticles in C57BL/6J mice plasma. Subcutaneous injections of MA and HQ increased vascular permeability by 1.54 fold and 1.27 fold correspondingly. In addition, the exposure of primary cardiac microvascular endothelial cells to MA increased vascular permeability detected by transendothelial monolayer resistance and by fluorescently labeled dextrans diffusion. The bulk RNA sequencing of endothelial cells exposed to MA for 2, 6, and 24 hours showed MA-dependent upregulation of heat shock-related pathways at 2 and 6 hours, dysregulation of GTPases at 6 hours, and altered cytoskeleton organization at 24 hours of exposure. We found that the HSP70 protein induced by MA in endothelial cells is colocalized with F-actin foci. HSP70 inhibitor 17AAG and HSP90 inhibitor JG98 attenuated MA-induced endothelial permeability, while HSP activator TRC enhanced endothelial leakage. Moreover, MA induced Rac1 GTPase activity, while Rho GTPase inhibitor Y-27632 attenuated MA-induced endothelial permeability. We showed that benzene metabolites compromised the endothelial barrier by altering HSP- and GTPase-related signaling pathways.