p38 and Casein Kinase 2 Mediate Ribonuclease 1 Repression in Inflamed Human Endothelial Cells via Promoter Remodeling Through Nucleosome Remodeling and Deacetylase Complex

Abstract

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 RNASE1 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 RNASE1 promoter and subsequent promoter remodeling.

Deficiencies of Runx3 and tissue-resident CD4+ intestinal epithelial lymphocytes link intestinal dysbiosis and inflammation in mouse and human spondyloarthropathy

“…In CD8 + T cells, an AS-risk allele of RUNX3 was shown to bind components of the NuRD complex and Aiolos more strongly than the protective allele [21]. Our data demonstrating lower levels of DP T cells in SI and blood in AS are consistent with this deficiency, and increases in CD4 lo CD8 hi DP with TNF inhibition implicate epigenetic regulation, potentially through the NuRD complex [48], which is central to repression of Runx3 gene expression. Furthermore, Runx3 expression was reduced in CD4 + T cells in SKG mice and Runx3-regulated genes account for a high proportion of the DE genes in SKG ileum.…”

Bacterial extracellular vesicles repress the vascular protective factor RNase1 in human lung endothelial cells

“…BAY11-7082 itself slightly downregulated RNase1 and elevated the repressive effect of TNF-α and OMVs. However, previous studies by Gansler et al and our group did not observe any impact of NF-κB inhibition on RNase1 mRNA expression in primary human umbilical vein ECs [ 34 , 35 ]. Furthermore, JNK signaling was found to be important for physiological RNase1 expression, as JNK inhibition repressed RNase1 [ 35 ].…”

“…However, previous studies by Gansler et al and our group did not observe any impact of NF-κB inhibition on RNase1 mRNA expression in primary human umbilical vein ECs [ 34 , 35 ]. Furthermore, JNK signaling was found to be important for physiological RNase1 expression, as JNK inhibition repressed RNase1 [ 35 ]. These findings suggest that RNase1 regulation in ECs may be organ-specific and vary depending on the physiological demands of the vascular bed [ 78 – 81 ].…”

“…However, Ruxolitinib treatment of HULEC-5a prior to OMV stimulation did not prevent RNase1 repression and Ruxolitinib treatment alone increased RNase1 expression. Little is known about the underlying molecular pathways of RNase1 regulation in ECs, but referred data primarily focused on p38 and histone deacetylase 2 (HDAC2)-mediated mechanisms [ 35 , 36 ]. Besides the possibility of off-target effects of Ruxolitinib, JAK1 can also be associated to IL-6 signaling [ 75 ].…”

Inflammatory stress-mediated chromatin changes underlie dysfunction in endothelial cells

“…For example, in rheumatoid arthritis patients, the non-immune cells responsible for removing debris or synoviocytes, but not macrophages, demonstrated prolonged expression of genes with a single TNF-alpha pulse accompanied by an increase in chromatin accessibility 10 . Endothelial responses to inflammatory stress largely rely on the mitogen-activated kinase (MAPK) signal transduction, specifically, p38MAP kinase (p38MAPK) and c-Jun N-terminal kinase (JNK), both well-known stress-activated protein kinases, due to their essential roles in orchestrated stress responses, including cytokines 11,12 . Despite the significant role of inflammation in vascular disorders, the consequences of inflammatory stimuli on the chromatin organization of vascular endothelial cells and the contribution of febrile-like fever to endothelial dysfunction are poorly understood.…”