Tissue factor pathway inhibitor attenuates ER stress-induced inflammation in human M2-polarized macrophages

Biochem Biophys Res Commun. 2017 Sep 16;491(2):442-448. doi: 10.1016/j.bbrc.2017.07.070. Epub 2017 Jul 13.

Abstract

Endoplasmic reticulum (ER) stress has been shown to play a key role during the initiation and clinical progression of the cardiovascular diseases, such as atherosclerosis. We have recently shown that expression of tissue factor pathway inhibitor (TFPI) in human monocyte-derived macrophages (MDMs) was induced by cholesterol crystals (CC). In the present study we aimed to determine the role of TFPI under ER stress conditions using human MDMs. qRT-PCR and immunohistochemistry analysis were performed to determine the presence of the ER stress marker CCAAT/enhancer binding protein homologous protein (CHOP) and TFPI in human carotid plaque material and also in human MDMs polarized into pro-inflammatory M1 or anti-inflammatory M2 populations. CHOP mRNA levels were upregulated in the plaques compared to healthy vessels, and CHOP protein was localized in the same area as TFPI in the plaques. Both CHOP and TFPI mRNA levels were upregulated after CC treatment, especially in the M2 phenotype, and the ER stress inhibitor 4-phenylbutyric acid (PBA) reversed this effect. Furthermore, CC treatment increased the levels of the pro-inflammatory cytokines TNF-α, IL-6, and IL-8, which for TNF-α and IL-8 was inhibited by PBA, and reduced the levels of the anti-inflammatory cytokine IL-10 in M2-polarized macrophages. Knockdown of TFPI prior to CC treatment exacerbated TNF-α and IL-6 levels, but reduced IL-8 and IL-10 levels. Our results show that CC induce TFPI and cytokine expression in M2-polarized macrophages through activation of the ER stress pathway and that TFPI has a protective effect against TNF-α and IL-6 mediated inflammation. These mechanisms may have implications for the pathogenesis of atherosclerosis.

Keywords: Carotid endarterectomies; Cholesterol crystals; ER stress; Inflammation; Macrophages; TFPI.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Atherosclerosis / genetics*
  • Atherosclerosis / immunology
  • Atherosclerosis / pathology
  • Atherosclerosis / surgery
  • Carotid Arteries / drug effects
  • Carotid Arteries / immunology
  • Carotid Arteries / pathology
  • Carotid Arteries / surgery
  • Cholesterol / pharmacology*
  • Crystallization
  • Endarterectomy, Carotid
  • Endoplasmic Reticulum / drug effects
  • Endoplasmic Reticulum / genetics
  • Endoplasmic Reticulum / metabolism
  • Endoplasmic Reticulum Stress / drug effects
  • Endoplasmic Reticulum Stress / genetics*
  • Gene Expression Regulation
  • Humans
  • Interleukin-10 / genetics
  • Interleukin-10 / immunology
  • Interleukin-6 / genetics
  • Interleukin-6 / immunology
  • Interleukin-8 / genetics
  • Interleukin-8 / immunology
  • Lipoproteins / antagonists & inhibitors
  • Lipoproteins / genetics*
  • Lipoproteins / immunology
  • Macrophages / drug effects
  • Macrophages / immunology
  • Macrophages / pathology
  • Phenylbutyrates / pharmacology
  • Plaque, Atherosclerotic / genetics*
  • Plaque, Atherosclerotic / immunology
  • Plaque, Atherosclerotic / pathology
  • Plaque, Atherosclerotic / surgery
  • Primary Cell Culture
  • RNA, Messenger / genetics*
  • RNA, Messenger / immunology
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / metabolism
  • Signal Transduction
  • Transcription Factor CHOP / genetics
  • Transcription Factor CHOP / immunology
  • Tumor Necrosis Factor-alpha / genetics
  • Tumor Necrosis Factor-alpha / immunology

Substances

  • DDIT3 protein, human
  • IL10 protein, human
  • IL6 protein, human
  • Interleukin-6
  • Interleukin-8
  • Lipoproteins
  • Phenylbutyrates
  • RNA, Messenger
  • RNA, Small Interfering
  • Tumor Necrosis Factor-alpha
  • lipoprotein-associated coagulation inhibitor
  • Interleukin-10
  • Transcription Factor CHOP
  • 4-phenylbutyric acid
  • Cholesterol