Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5944119 | Atherosclerosis | 2015 | 10 Pages |
â¢Stat4â/âApoeâ/â deficient mice were generated.â¢Stat-4 deficiency resulted in the attenuated atherosclerosis.â¢Reduced atherogenesis was at least partially independent of Th1 cell-derived IFNγ.â¢STAT4 supports pro-inflammatory macrophage response in atherosclerosis.
Atherosclerosis is a chronic inflammatory process that leads to plaque formation in large and medium sized vessels. T helper 1 (Th1) cells constitute the majority of plaque infiltrating pro-atherogenic T cells and are induced via IFNγ-dependent activation of T-box (Tbet) and/or IL-12-dependent activation of signal transducer and activator of transcription 4 (STAT4). We thus aimed to define a role for STAT4 in atherosclerosis. STAT4-deficiency resulted in a â¼71% reduction (p < 0.001) in plaque burden in Stat4â/âApoeâ/â vs Apoeâ/â mice fed chow diet and significantly attenuated atherosclerosis (â¼31%, p < 0.01) in western diet fed Stat4â/âApoeâ/â mice. Surprisingly, reduced atherogenesis in Stat4â/âApoeâ/â mice was not due to attenuated IFNγ production in vivo by Th1 cells, suggesting an at least partially IFNγ-independent pro-atherogenic role of STAT4. STAT4 is expressed in T cells, but also detected in macrophages (MΦs). Stat4â/âApoeâ/âin vitro differentiated M1 or M2 MΦs had reduced cytokine production compare to Apoeâ/â M1 and M2 MΦs that was accompanied by reduced induction of CD69, I-Ab, and CD86 in response to LPS stimulation. Stat4â/âApoeâ/â MΦs expressed attenuated levels of CCR2 and demonstrated reduced migration toward CCL2 in a transwell assay. Importantly, the percentage of aortic CD11b+F4/80+Ly6Chi MΦs was reduced in Stat4â/âApoeâ/â vs Apoeâ/â mice. Thus, this study identifies for the first time a pro-atherogenic role of STAT4 that is at least partially independent of Th1 cell-derived IFNγ, and primarily involving the modulation of MΦ responses.