Inflammation‐mediated deacetylation of the ribonuclease 1 promoterviahistone deacetylase 2 in endothelial cells

Abstract

Ribonuclease 1 (RNase1) is a circulating extracellular endonuclease that regulates the vascular homeostasis of extracellular RNA and acts as a vessel‐ and tissue‐protective enzyme. Upon long‐term inflammation, high amounts of proinflammatory cytokines affect endothelial cell (EC) function by down‐regulation of RNase1. Here, we investigated the transcriptional regulation of RNase1 upon inflammation in HUVECs. TNF‐α or IL‐1β stimulation reduced the expression of RNase1 relative to the acetylation state of histone 3 at lysine 27 and histone 4 of the RNASE1 promoter. Inhibition of histone deacetylase (HDAC) 1, 2, and 3 by the specific class I HDAC inhibitor MS275 abolished the TNF‐α‐ or IL‐1β–mediated effect on the mRNA and chromatin levels of RNase1. Moreover, chromatin immunoprecipitation kinetics revealed that HDAC2 accumulates at the RNASE1 promoter upon TNF‐β stimulation, indicating an essential role for HDAC2 in regulating RNase1 expression. Thus, proinflammatory stimulation induced recruitment of HDAC2 to attenuate histone acetylation at the RNASE1 promoter site. Consequently, treatment with HDAC inhibitors may provide a new therapeutic strategy to stabilize vascular homeostasis in the context of inflammation by preventing RNase1 down‐regulation in ECs.—Bedenbender, K., Scheller, N., Fischer, S., Leiting, S., Preissner, K. T., Schmeck, B. T., Vollmeister, E. Inflammation‐mediated deacetylation of the ribonuclease 1 promoter via histone deacetylase 2 in endothelial cells. FASEB J. 33, 9017–9029 (2019). http://www.fasebj.org

Endothelial Ribonuclease 1 in Cardiovascular and Systemic Inflammation

“…In 2014, Gansler and colleagues implicated a regulatory mechanism for RNase1 repression, dependent on histone deacetylases (HDACs) rather than Nuclear factor κ B-mediated signaling by using specific pharmaceutical inhibitors (Gansler et al, 2014). Based on these findings, we further investigated the precise molecular mechanisms of RNase1 regulation: The promoter region of RNASE1 was identified to examine the HDAC-mediated changes of RNASE1 at chromatin level (Bedenbender et al, 2019). Thereby, proinflammatory stimulation of HUVEC resulted in the loss of different markers associated to active transcription, specific deacetylation of the RNASE1 promoter at histone 4 and histone 3 lysine 27, along with the loss of RNA polymerase II transcription machinery binding (Kouzarides, 2007;Wang et al, 2008;Bedenbender et al, 2019).…”

“…Based on these findings, we further investigated the precise molecular mechanisms of RNase1 regulation: The promoter region of RNASE1 was identified to examine the HDAC-mediated changes of RNASE1 at chromatin level (Bedenbender et al, 2019). Thereby, proinflammatory stimulation of HUVEC resulted in the loss of different markers associated to active transcription, specific deacetylation of the RNASE1 promoter at histone 4 and histone 3 lysine 27, along with the loss of RNA polymerase II transcription machinery binding (Kouzarides, 2007;Wang et al, 2008;Bedenbender et al, 2019). Additionally, administration of the specific HDAC inhibitor MS275, targeting the class I HDACs HDAC1-3, successfully recovered RNase1 mRNA expression upon inflammation (via TNF-α) as consequence of restored histone acetylation and RNA polymerase II recruitment (Bedenbender et al, 2019).…”

“…Thereby, proinflammatory stimulation of HUVEC resulted in the loss of different markers associated to active transcription, specific deacetylation of the RNASE1 promoter at histone 4 and histone 3 lysine 27, along with the loss of RNA polymerase II transcription machinery binding (Kouzarides, 2007;Wang et al, 2008;Bedenbender et al, 2019). Additionally, administration of the specific HDAC inhibitor MS275, targeting the class I HDACs HDAC1-3, successfully recovered RNase1 mRNA expression upon inflammation (via TNF-α) as consequence of restored histone acetylation and RNA polymerase II recruitment (Bedenbender et al, 2019). The HDAC enzyme responsible for this regulatory process was further identified as HDAC2, demonstrated by its accumulation and deacetylation of the RNASE1 promoter upon proinflammatory stimulation.…”

“…in this context (Sengupta and Seto, 2004;Yang and Seto, 2008;Bedenbender et al, 2019). In respect to the underlying signaling cascade, only little is known from literature.…”

“…However, it is worth to mention that the described proinflammatory agents have the potential to induce an inflammatory loop of cytokine production via Nuclear factor kappa B signaling (Wajant and Scheurich, 2011), which in turn might increase the negative impact of proinflammatory conditions on RNase1. Nevertheless, several intermediate steps in the RNase1 regulatory signaling cascade in human ECs can be speculated: RNase1 regulation in HUVEC was identified as a specific proinflammatory reaction mediated via e.g., TNF-α, IL-1β or polyinosinic polycytidylic acid (poly I:C) signaling (Gansler et al, 2014;Bedenbender et al, 2019). These results assume a regulatory mechanism by common signaling cascade(s) that is independent from Nuclear factor kappa B.…”