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

Benzene is a hazardous air pollutant and environmental contaminant emitted
into the atmosphere from motor vehicle exhaust, fuel evaporation at gas
stations, and during man-made and natural disasters such as wildfires and
military burn pit incinerations. Chronic exposure to benzene, even at
lower levels, is associated with elevated risk for cardiovascular
diseases, including atherosclerosis and cardiac dysfunction. However, the
mechanisms of benzene-induced cardiovascular complications remain unknown.
Our data suggest that intradermal injections of benzene metabolite
trans,trans-muconaldehyde (MA) increased vascular permeability by 54% in
C57BL6 mice, while intravenous administration of MA propagated endothelial
injury measured by elevated circulating endothelial-specific
microparticles. The exposure of primary cardiac microvascular endothelial
cells to MA increased vascular permeability, which was detected by
transendothelial monolayer electrical resistance and by fluorescently
labeled dextran’s diffusion. To investigate the molecular mechanisms of
MA-induced endothelial permeability, we exposed mouse cardiac
microvascular endothelial cells (CMVEC) to 10 μM MA for 6 hours and human
aortic endothelial cells (HAEC) for 2, 6, and 18 hours. Then, we analysed
differentially regulated genes (DEG) using bulk RNA sequencing. The
transcriptomic analysis indicated that MA increased the expression of
stress-response and chaperone genes and perturbed GTPase regulation in
endothelial cells. The functional importance of HSP and GTPase signaling
pathway in MA-induced endothelial permeability was confirmed in vitro and
in vivo. In conclusion, benzene metabolites increased vascular
permeability through activation of HSP and GTPase signaling pathways.