Bedenbender Katrin, Beinborn Isabell, Vollmeister Evelyn, Schmeck Bernd
Institute for Lung Research, Universities of Giessen and Marburg Lung Center, Philipps-University Marburg, Marburg, Germany.
Department of Pulmonary and Critical Care Medicine, Department of Medicine, University Medical Center Giessen and Marburg, Philipps-University Marburg, Marburg, Germany.
Front Cell Dev Biol. 2020 Oct 15;8:563604. doi: 10.3389/fcell.2020.563604. eCollection 2020.
Vascular pathologies, such as thrombosis or atherosclerosis, are leading causes of death worldwide and are strongly associated with the dysfunction of vascular endothelial cells. In this context, the extracellular endonuclease Ribonuclease 1 (RNase1) acts as an essential protective factor in regulation and maintenance of vascular homeostasis. However, long-term inflammation causes strong repression of RNase1 expression, thereby promoting endothelial cell dysfunction. This inflammation-mediated downregulation of RNase1 in human endothelial cells is facilitated via histone deacetylase (HDAC) 2, although the underlying molecular mechanisms are still unknown. Here, we report that inhibition of c-Jun N-terminal kinase by small chemical compounds in primary human endothelial cells decreased physiological RNase1 mRNA abundance, while p38 kinase inhibition restored repressed RNase1 expression upon proinflammatory stimulation with tumor necrosis factor alpha (TNF-α) and poly I:C. Moreover, blocking of the p38 kinase- and HDAC2-associated kinase casein kinase 2 (CK2) by inhibitor as well as small interfering RNA (siRNA)-knockdown restored RNase1 expression upon inflammation of human endothelial cells. Further downstream, siRNA-knockdown of chromodomain helicase DNA binding protein (CHD) 3 and 4 of the nucleosome remodeling and deacetylase (NuRD) complex restored RNase1 repression in TNF-α treated endothelial cells implicating its role in the HDAC2-containing repressor complex involved in RNase1 repression. Finally, chromatin immunoprecipitation in primary human endothelial cells confirmed recruitment of the CHD4-containing NuRD complex and subsequent promoter remodeling via histone deacetylation at the promoter in a p38-dependent manner upon human endothelial cell inflammation. Altogether, our results suggest that endothelial RNase1 repression in chronic vascular inflammation is regulated by a p38 kinase-, CK2-, and NuRD complex-dependent pathway resulting in complex recruitment to the promoter and subsequent promoter remodeling.
血管病变，如血栓形成或动脉粥样硬化，是全球主要的死亡原因，并且与血管内皮细胞功能障碍密切相关。在这种情况下，细胞外核酸内切酶核糖核酸酶1（RNase1）在血管稳态的调节和维持中起着重要的保护作用。然而，长期炎症会导致RNase1表达受到强烈抑制，从而促进内皮细胞功能障碍。尽管潜在的分子机制尚不清楚，但人内皮细胞中这种炎症介导的RNase1下调是通过组蛋白脱乙酰酶（HDAC）2来促进的。在此，我们报告，在原代人内皮细胞中，用小分子化合物抑制c-Jun N端激酶会降低生理性RNase1 mRNA丰度，而抑制p38激酶可恢复在肿瘤坏死因子α（TNF-α）和聚肌苷酸:聚胞苷酸（poly I:C）促炎刺激下被抑制的RNase1表达。此外，用抑制剂阻断p38激酶和与HDAC2相关的酪蛋白激酶2（CK2）以及用小干扰RNA（siRNA）敲低CK2，均可在人内皮细胞炎症时恢复RNase1表达。在更下游，对核小体重塑和脱乙酰酶（NuRD）复合物的染色质结构域解旋酶DNA结合蛋白（CHD）3和4进行siRNA敲低，可恢复TNF-α处理的内皮细胞中RNase1的抑制作用，这表明其在参与RNase1抑制的含HDAC2的抑制复合物中发挥作用。最后，原代人内皮细胞中的染色质免疫沉淀证实，在人内皮细胞炎症时，含CHD4的NuRD复合物以p38依赖的方式被募集到启动子，并随后通过组蛋白去乙酰化进行启动子重塑。总之，我们的结果表明，慢性血管炎症中内皮RNase1的抑制是由p38激酶、CK2和NuRD复合物依赖的途径调节的，导致复合物募集到启动子并随后进行启动子重塑。
