Global Transcriptional Profiling Reveals Novel Autocrine Functions of Interleukin 6 in Human Vascular Endothelial Cells

Background. Interleukin 6 (IL6) is a multifunctional cytokine produced by various cells, including vascular endothelial cells. IL6 has both pro- and non-/anti-inflammatory functions, and the response to IL6 is dependent on whether it acts via the membrane-bound IL6 receptor α (IL6Rα) (classic signal...

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Main Authors: Liza U. Ljungberg, Mulugeta M. Zegeye, Caroline Kardeby, Knut Fälker, Dirk Repsilber, Allan Sirsjö
Format: Article
Language:English
Published: Wiley 2020-01-01
Series:Mediators of Inflammation
Online Access:http://dx.doi.org/10.1155/2020/4623107
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author Liza U. Ljungberg
Mulugeta M. Zegeye
Caroline Kardeby
Knut Fälker
Dirk Repsilber
Allan Sirsjö
author_facet Liza U. Ljungberg
Mulugeta M. Zegeye
Caroline Kardeby
Knut Fälker
Dirk Repsilber
Allan Sirsjö
author_sort Liza U. Ljungberg
collection DOAJ
description Background. Interleukin 6 (IL6) is a multifunctional cytokine produced by various cells, including vascular endothelial cells. IL6 has both pro- and non-/anti-inflammatory functions, and the response to IL6 is dependent on whether it acts via the membrane-bound IL6 receptor α (IL6Rα) (classic signaling) or the soluble form of the receptor (transsignaling). As human endothelial cells produce IL6 and at the same time express IL6Rα, we hypothesized that IL6 may have autocrine functions. Methods. Knockdown of IL6 in cultured human endothelial cells was performed using siRNA. Knockdown efficiency was evaluated using ELISA. RNA sequencing was employed to characterize the transcriptional consequence of IL6 knockdown, and Ingenuity Pathway Analysis was used to further explore the functional roles of IL6. Results. Knockdown of IL6 in cultured endothelial cells resulted in a 84-92% reduction in the release of IL6. Knockdown of IL6 resulted in dramatic changes in transcriptional pattern; knockdown of IL6 in the absence of soluble IL6Rα (sIL6Rα) led to differential regulation of 1915 genes, and knockdown of IL6 in the presence of sIL6Rα led to differential regulation of 1967 genes (fold change 1.5, false discovery rate<0.05). Pathway analysis revealed that the autocrine functions of IL6 in human endothelial cells are mainly related to basal cellular functions such as regulation of cell cycle, signaling, and cellular movement. Furthermore, we found that knockdown of IL6 activates functions related to adhesion, binding, and interaction of endothelial cells, which seem to be mediated mainly via STAT3. Conclusion. In this study, a large number of novel genes that are under autocrine regulation by IL6 in human endothelial cells were identified. Overall, our data indicate that IL6 acts in an autocrine manner to regulate basal cellular functions, such as cell cycle regulation, signaling, and cellular movement, and suggests that the autocrine functions of IL6 in human endothelial cells are mediated via IL6 classic signaling.
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spelling doaj-art-a2d6df618ba14717942fcb27697598892025-02-03T05:44:13ZengWileyMediators of Inflammation0962-93511466-18612020-01-01202010.1155/2020/46231074623107Global Transcriptional Profiling Reveals Novel Autocrine Functions of Interleukin 6 in Human Vascular Endothelial CellsLiza U. Ljungberg0Mulugeta M. Zegeye1Caroline Kardeby2Knut Fälker3Dirk Repsilber4Allan Sirsjö5School of Medical Sciences, Cardiovascular Research Centre, Örebro University, Örebro, SwedenSchool of Medical Sciences, Cardiovascular Research Centre, Örebro University, Örebro, SwedenSchool of Medical Sciences, Cardiovascular Research Centre, Örebro University, Örebro, SwedenSchool of Medical Sciences, Cardiovascular Research Centre, Örebro University, Örebro, SwedenSchool of Medical Sciences, Cardiovascular Research Centre, Örebro University, Örebro, SwedenSchool of Medical Sciences, Cardiovascular Research Centre, Örebro University, Örebro, SwedenBackground. Interleukin 6 (IL6) is a multifunctional cytokine produced by various cells, including vascular endothelial cells. IL6 has both pro- and non-/anti-inflammatory functions, and the response to IL6 is dependent on whether it acts via the membrane-bound IL6 receptor α (IL6Rα) (classic signaling) or the soluble form of the receptor (transsignaling). As human endothelial cells produce IL6 and at the same time express IL6Rα, we hypothesized that IL6 may have autocrine functions. Methods. Knockdown of IL6 in cultured human endothelial cells was performed using siRNA. Knockdown efficiency was evaluated using ELISA. RNA sequencing was employed to characterize the transcriptional consequence of IL6 knockdown, and Ingenuity Pathway Analysis was used to further explore the functional roles of IL6. Results. Knockdown of IL6 in cultured endothelial cells resulted in a 84-92% reduction in the release of IL6. Knockdown of IL6 resulted in dramatic changes in transcriptional pattern; knockdown of IL6 in the absence of soluble IL6Rα (sIL6Rα) led to differential regulation of 1915 genes, and knockdown of IL6 in the presence of sIL6Rα led to differential regulation of 1967 genes (fold change 1.5, false discovery rate<0.05). Pathway analysis revealed that the autocrine functions of IL6 in human endothelial cells are mainly related to basal cellular functions such as regulation of cell cycle, signaling, and cellular movement. Furthermore, we found that knockdown of IL6 activates functions related to adhesion, binding, and interaction of endothelial cells, which seem to be mediated mainly via STAT3. Conclusion. In this study, a large number of novel genes that are under autocrine regulation by IL6 in human endothelial cells were identified. Overall, our data indicate that IL6 acts in an autocrine manner to regulate basal cellular functions, such as cell cycle regulation, signaling, and cellular movement, and suggests that the autocrine functions of IL6 in human endothelial cells are mediated via IL6 classic signaling.http://dx.doi.org/10.1155/2020/4623107
spellingShingle Liza U. Ljungberg
Mulugeta M. Zegeye
Caroline Kardeby
Knut Fälker
Dirk Repsilber
Allan Sirsjö
Global Transcriptional Profiling Reveals Novel Autocrine Functions of Interleukin 6 in Human Vascular Endothelial Cells
Mediators of Inflammation
title Global Transcriptional Profiling Reveals Novel Autocrine Functions of Interleukin 6 in Human Vascular Endothelial Cells
title_full Global Transcriptional Profiling Reveals Novel Autocrine Functions of Interleukin 6 in Human Vascular Endothelial Cells
title_fullStr Global Transcriptional Profiling Reveals Novel Autocrine Functions of Interleukin 6 in Human Vascular Endothelial Cells
title_full_unstemmed Global Transcriptional Profiling Reveals Novel Autocrine Functions of Interleukin 6 in Human Vascular Endothelial Cells
title_short Global Transcriptional Profiling Reveals Novel Autocrine Functions of Interleukin 6 in Human Vascular Endothelial Cells
title_sort global transcriptional profiling reveals novel autocrine functions of interleukin 6 in human vascular endothelial cells
url http://dx.doi.org/10.1155/2020/4623107
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