Early life stress-Induced aortic NOX4 and VCAM1 expression is mediated by endothelial cell HDAC9

Early life stress (ELS) refers to adverse childhood experiences, including stressors such as parental separation, household dysfunction, and exposure to trauma, and is well-established to be associated with increased risk for cardiovascular disease (CVD) in adulthood. We previously found that aorta from mice exposed to ELS have significantly higher oxidative stress and inflammation. Utilizing immunohistochemical localization, we found that aortic endothelial cells show increased HDAC9 expression in adult MSEW mice compared to NR mice. HDAC9, a class II HDAC, is known to be associated with vascular dysfunction in humans and mice. We hypothesized that ELS exposure induces increased endothelial cell HDAC9 expression and that endothelial cell HDAC9 mediates increased pro-oxidant gene, NOX4, and pro-inflammatory gene VCAM-1, expression in the aorta of mice exposed to ELS. We utilized a mouse model of ELS, Maternal Weaning and Early Separation (MSEW), with normal-reared (NR) mice as controls with tamoxifen-inducible endothelial cell specific HDAC9 wild-type (iEC-HDAC9 WT) and knockout (iEC-HDAC9 KO) mice. Briefly, MSEW mice were separated from their mothers for increasing durations from days 2 to 16 post-birth and weaned on day 17. NR mice remained undisturbed until weaning on day 21. Aorta from adult iEC-HDAC9 WT MSEW mice have significantly greater NOX4 expression compared to iEC-HDAC9 KO MSEW (75.9 ± 18.4 copies/μL, 34.1 ± 9.0 copies/μL, n=9, p=0.0197). Additionally, aorta from iEC-HDAC9 KO MSEW mice had significantly lower VCAM-1 expression than aorta from iEC-HDAC9 WT MSEW mice critical for inflammatory cell migration (78.2 ± 19.2 copies/μL, 218.2 ± 69.8 copies/μL, n=9, p=0.030). These findings suggest that endothelial cell-specific HDAC9 mediates NOX4-driven oxidative stress and VCAM-1 contributing to endothelial dysfunction and inflammation with exposure to ELS. To follow up these findings, we further hypothesized that ELS exposure would promote macrophage priming with increased HDAC9 expression, thereby contributing to ELS-induced inflammation. Bone marrow-derived macrophages (BMDM) from MSEW and NR groups were cultured in media supplemented with macrophage colony stimulating factor for seven days followed by acute lipopolysaccharide stimulation. BMDM from MSEW mice showed significantly increased HDAC9 to the NR group (228.9 ± 143.3 copies/μL, 1.8 ± 0.8 copies/μL, p=0.014). These findings suggest BMDM from MSEW mice are primed for inflammation in contrast to BMDM from NR mice. We conclude that targeting HDAC9, an epigenetic regulator associated with ELS, may alleviate oxidative stress and decrease inflammation for individuals with ELS exposure. NIH P01HL158500 This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.