Data_Sheet_2_Tribbles 3 deficiency promotes atherosclerotic fibrous cap thickening and macrophage-mediated extracellular matrix remodelling.docx

Tribbles 3 (TRIB3) modulates lipid and glucose metabolism, macrophage lipid uptake, with a gain-of-function variant associated with increased cardiovascular risk. Here we set out to examine the role of this pseudokinase in atherosclerotic plaque development. Human endarterectomy atherosclerotic tissue specimens analysed by immunofluorescence showed upregulated TRIB3 in unstable plaques and an enrichment in unstable regions of stable plaques. Atherosclerosis was induced in full body Trib3KO and Trib3WT littermate mice by injecting mPCSK9 expressing adeno-associated virus and western diet feeding for 12 weeks. Trib3KO mice showed expanded visceral adipose depot while circulatory lipid levels remained unaltered compared to wildtype mice. Trib3KO mice aortae showed a reduced plaque development and improved plaque stability, with increased fibrous cap thickness and collagen content, which was accompanied by increased macrophage content. Analysis of both mouse and human macrophages with reduced TRIB3 expression showed elongated morphology, increased actin expression and altered regulation of genes involved in extracellular matrix remodelling. In summary, TRIB3 controls plaque development and may be atherogenic in vivo. Loss of TRIB3 increases fibrous cap thickness via altered metalloproteinase expression in macrophages, thus inhibiting collagen and elastic fibre degradation, suggesting a role for TRIB3 in the formation of unstable plaques.

Tribbles 3（TRIB3）调控脂质和葡萄糖代谢、巨噬细胞脂质摄取，其功能获得性变异与心血管风险增加相关。本研究旨在探讨此伪激酶在动脉粥样硬化斑块形成中的作用。通过免疫荧光分析的人体颈动脉内膜切除术动脉粥样硬化组织样本显示，在易损斑块和不稳定斑块的不稳定区域中TRIB3表达上调。通过注射表达mPCSK9的腺相关病毒和西方饮食喂养12周诱导全身性Trib3KO和Trib3WT同窝小鼠发生动脉粥样硬化。与野生型小鼠相比，Trib3KO小鼠内脏脂肪库扩大，而循环脂质水平保持不变。Trib3KO小鼠的主动脉表现出斑块发育减少和斑块稳定性改善，纤维帽厚度和胶原蛋白含量增加，伴随着巨噬细胞含量增加。对TRIB3表达降低的小鼠和人类巨噬细胞的分析显示，细胞形态拉长，肌动蛋白表达增加，以及参与细胞外基质重塑的基因调节发生改变。总之，TRIB3控制斑块发育，可能在体内具有致动脉粥样硬化的作用。TRIB3的丢失通过巨噬细胞中金属蛋白酶表达的改变增加纤维帽厚度，从而抑制胶原蛋白和弹性纤维的降解，暗示TRIB3在不稳定斑块形成中的作用。