Proinflammatory Macrophage Phenotype Modulates Vascular Smooth Muscle Cell Differentiation via the Histone Demethylase JMJD3

Patients with diabetes are at increased risk of a multitude of vascular diseases, including atherosclerosis, which is driven by macrophage-mediated inflammation. While it is known that atherosclerosis is characterized by a proliferative, synthetic smooth muscle phenotype that underlies disease, the exact role of other cell types, namely myeloid cells and their interaction with smooth muscle cells is less understood. Furthermore, how diabetes modifies atherosclerotic severity is another important question. To address this, we performed an epigenetic superarray to identify key chromatin modifying enzymes in vascular smooth muscle cells (vSMC) from normal diet (ND) and diabetic-induced obese (DIO) aortas. We identified the histone demethylase, JMJD3, which was significantly decreased in DIO compared to ND vSMC (p<0.05). Furthermore, in our single cell RNA-seq data set from human atherosclerotic lesions, JMJD3 was expressed in smooth muscle cells. It is known that macrophages in atherosclerotic lesions exhibit a pro-inflammatory phenotype. To model this pro-inflammatory process, we stimulated bone marrow derived macrophages with LPS and found that supernatant from LPS-stimulated BMDMs significantly inhibited smooth muscle specific gene expression (SMA, SM22, CNN1, SM-MHC) as well as expression of JMJD3 compared to control media (p<0.05). Additionally, siRNA-mediated knockdown of JMJD3 in vSMC reduced SMC-specific gene expression, and treatment of mouse aortic vSMC with the JMJD3 selective inhibitor, GSK4J, decreased smooth muscle gene expression (p<0.05). Our data shows that pro-inflammatory macrophages drive reduced vascular smooth muscle gene expression and that JMJD3 in SMC is a regulator of this process. These results implicate JMJD3 in macrophage-smooth muscle cell crosstalk in the pro-inflammatory state and identify it as a potential therapeutic target in the management of atherosclerosis. Disclosure K.D.Mangum: None. A.Joshi: None. P.Mazumder: None. S.Wolf-fortune: None. E.Barrett: None. B.Moore: None. F.M.Davis: None. K.Gallagher: None. Funding National Institutes of Health (1F32DK131799-01); American College of Surgeons; Vascular & Endovascular Surgery Society