IL-23/IL-17A轴对CABG静脉桥再狭窄过程中炎症反应的影响及机制研究

Adaptation of saphenous vein graft to their new arterial environment is characterized by vascular remodeling after coronary artery bypass grafting. But the excessive remodeling resulted in vein graft stenosis and CABG failure. Immune response could modulate the vein graft remodeling. Our preliminary studies suggested that the expression of IL-17A increased in the grafted vein among all IL-17 family members; IL-23 and IL-17A were higher in high risk of vein graft failure; IL-17A knockout mouse showed attenuated vascular remodeling and decreases level of inflammatory cytokines. However, the exact mechanism of IL-23/IL-17 axis in vein graft remodeling was remained unclear. In this project, we hypothesis that during the vein graft remodeling, IL-23 promotes the activation of IL-17A+T cells to produce IL-17A, which could promote the proliferation and migration of smooth muscle cells and intimal hyperplasia by enhancing inflammation response. To verify this hypothesis, we will use neutralization antibodies of IL-23 and IL-17A, IL-17A-/- mouse in vivo, RNA-seq and cells co-culture in vitro to reveal the molecular mechanism of IL-23/IL-17A axis in vein graft remodeling, and explore the relationship between the degrees of vein graft stenosis and IL-23 and IL-17A levels by using a follow-up cohort of CABG patients. Our research will provide the new theoretical and experimental basis for intervention of vein graft stenosis after CABG.

冠状动脉旁路移植术使用的大隐静脉桥血管会发生血管重塑以适应动脉血流环境，但是过度重塑引起桥血管的狭窄导致手术失败。免疫炎症反应可调控桥血管的重塑过程。我们前期研究发现小鼠静脉移植术后IL-17A表达上调最明显,IL-17A及上游因子IL-23表达在再狭窄高危人群中的显著增加。IL-17A敲除小鼠移植血管的重塑程度减轻，炎症因子表达减少，但IL-23/IL-17A轴如何在移植后血管重塑过程中发挥作用尚不清楚。据此提出科学假设：IL-23激活IL-17A+T细胞分泌IL-17A调控炎症反应，促进平滑肌细胞的增殖和迁移，加剧静脉移植后再狭窄的程度。本课题拟用小鼠静脉-动脉移植的模型，使用IL-23/IL-17A中和抗体以及IL-17A-/-小鼠检测对血管重塑的影响，并结合转录组测序和功能验证明确IL-17A在血管重塑中的作用机制，从而发现移植桥血管再狭窄预防和治疗的新靶点。

冠状动脉旁路移植术使用的大隐静脉桥血管会发生血管重塑以适应动脉血流环境，但是过度重塑引起桥血管的狭窄导致手术失败。免疫炎症反应可调控桥血管的重塑过程。前期研究发现小鼠静脉移植术后IL-17A表达上调最明显,IL-17A及上游因子IL-23表达在再狭窄高危人群中的显著增加。IL-17A敲除小鼠移植血管的重塑程度减轻，炎症因子表达减少。既往研究表明，再狭窄过程中血管平滑肌细胞表型转化是主要病理过程。平滑肌细胞表型转化会发生成骨样转化甚至钙化，从而造成移植静脉再狭窄。为了研究IL-17A与平滑肌细胞表型转化、钙化等的过程，我们在临床样本发现钙化相关疾病中IL17A及其相关炎症因子等水平显著升高，与成骨转录因子RUNX2表达呈正相关。在小鼠模型中注射IL-17A中和抗体可以显著降低了模型小鼠的钙化水平。单细胞测序数据、人瓣膜免疫荧光染色及原代瓣膜细胞检测显示IL-17RA主要表达在巨噬细胞、内皮细胞。RT-PCR发现IL17A激活巨噬细胞产生炎症IL-6和趋化因子。转录组学数据发现IL17A激活内皮细胞炎症相关通路，促进CXCL1、CXCL8、CCL2等多种趋化因子及促成骨转分化相关因子（IL6）的表达。这些结果显示IL-17A-IL-17RA通路活化可能通过促进巨噬细胞和内皮细胞的炎症反应及促进平滑肌细胞成骨样转化，从而加速移植静脉再狭窄。同时我们发现， miR-223-3p可以通过STAT3抑制成骨样转化这一关键病理过程。