The Role of Lysine-Specific Demethylase 1 (LSD1) in Shaping the Endothelial Inflammatory Response

Abstract

Background/Aims: Inflammation is the body’s natural response to stress in the broadest sense. The regulatory mechanisms that control this process, some of which are still unclear, are needed to balance the immune response, but also when insufficient, can cause immunodeficiency resulting in infection, cancer, neurodegeneration or other serious disorders. In this study, we focused on defining the role of lysine-specific demethylase 1 (LSD1), an enzyme involved in modulating the methylation state of lysine, including histone and non-histone proteins, in shaping the inflammatory profile of endothelial cells. Methods: To determine the role of LSD1 in the inflammatory response of ECs, cells were stimulated with lipopolysaccharide (100 ng/ml LPS) in the presence and absence of an LSD1 inhibitor (2-PCPA). A transcription model of LSD1 deficient cells (HMEC-1 LSD1 KD) obtained by lentiviral shRNA transduction was also used. The indicated cellular models were analyzed by gene profiling, monitoring of p65 shuttling by Western blotting and immunofluorescence staining. Also chromatin immunoprecipitation (ChIP) was performed to identify the interactions between selected: IL-6/p65 and LSD1. Results: Analysis of both experimental models revealed an altered inflammatory response following both LSD1 inhibition and LSD1 silencing. We observed decreased U-937 monocytes recruitment to LPS-activated endothelial cells and decreased extracellular secretion of many proinflammatory cytokines, also confirmed at the transcript level by RT-qPCR. Monitoring of the LPS-induced p65 translocation revealed inhibition of the NF-κB subunit in LSD1 KD vs nonT as well as due to pretreatment of 2-PCPA cells. Gene profiling performed with RNA microarrays confirmed the obtained biochemical data at the transcript level. Conclusion: In conclusion, the conducted studies showed a proinflammatory profile of LSD1 activity in endothelial cells, revealed by the inhibition of the enzyme activity and confirmed at the transcriptional level by the inhibition of its expression. Although we found significant changes in the modification of interactions between monocytes and endothelial cells as well as in cytokine/chemokine release and expression that were consistent with the altered NF-κB-p65 translocation into the nucleus, we did not identify a direct interaction between LSD1 and the transcription factor. Our finding may have important implications for prevention of cardiovascular diseases at their first stage - activation of the endothelium as well as for tumor cell biology, providing evidence for the use of LSD1 inhibitors to reduce the inflammatory response, which enhances tumor tissue remodeling, angiogenesis and metastasis.

Pharmacological Inhibition of Lysine-Specific Demethylase 1A Reduces Atherosclerotic Lesion Formation in Apolipoprotein E-Deficient Mice by a Mechanism Involving Decreased Oxidative Stress and Inflammation; Potential Implications in Human Atherosclerosis

“…It is worth mentioning that dysfunctional endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) are instrumental in the process of atheroma formation. Interestingly, pharmacological inhibition of LSD1 reduced EC proliferation and inflammatory response, VSMC proliferation, and neointimal hyperplasia [ 59 , 60 , 61 ]. Together, these data suggest that LSD1-related signaling pathways could regulate important pathological aspects in multiple cell types implicated in atherogenesis.…”

Rheum rhaponticum and Rheum rhabarbarum Extracts as Modulators of Endothelial Cell Inflammatory Response

“…After 16–24 h, when the cells reached 100% confluency and formed paving stones, the medium was changed to a fresh one, containing 1–50 μg/mL extracts from the petioles of R. rhaponticum or R. rhabarbarum ; 1–50 μg/mL extract from the roots of R. rhaponticum ; 1–30 μg/mL extract from the roots of R. rhabarbarum ; 1–50 μg/mL RHPT or 1–25 μg/mL RHPG. After 16 h, LPS (at the final concentration of 1 µg/mL) was added, and the incubation was continued for the next 4 h. Analysis of the adhesion of monocytes to the activated endothelial was performed as described previously [ 21 ]. U-937 cells were stained with Hoechst 33342 (1 μM), in the dark, for 10 min, and an excess of the fluorescent probe was removed by a series of RPMI-1640 medium washes.…”

The Role of LSD1 and LSD2 in Cancers of the Gastrointestinal System: An Update

“…The majority of research defining the role of LSD1 in metabolism is connected to cancer biology, and little is known about the participation of LSD1 in endothelial cell proliferation, which is critical for circulatory functions and cancer development and metastasis [93]. The expression of LSD1 being higher in cancers leads to a proposition of it being an anti-cancer target and various studies report that the pharmacological inhibition of LSD1 could be a potential treatment strategy for various cancers [94].…”