scholarly journals Anti-Inflammatory Effects of HDL (High-Density Lipoprotein) in Macrophages Predominate Over Proinflammatory Effects in Atherosclerotic Plaques

2019 ◽  
Vol 39 (12) ◽  
Author(s):  
Panagiotis Fotakis ◽  
Vishal Kothari ◽  
David G. Thomas ◽  
Marit Westerterp ◽  
Matthew M. Molusky ◽  
...  
Keyword(s):  
Gene Expression ◽  
High Density Lipoprotein ◽  
Density Lipoprotein ◽  
High Density ◽  
Mitogen Activated Protein Kinase ◽  
Endoplasmic Reticulum Stress Response ◽  
Cholesterol Depletion ◽  
Inflammatory Gene Expression ◽  
Inflammatory Gene ◽  
Anti Inflammatory

Objective: HDL (high-density lipoprotein) infusion reduces atherosclerosis in animal models and is being evaluated as a treatment in humans. Studies have shown either anti- or proinflammatory effects of HDL in macrophages, and there is no consensus on the underlying mechanisms. Here, we interrogate the effects of HDL on inflammatory gene expression in macrophages. Approach and Results: We cultured bone marrow–derived macrophages, treated them with reconstituted HDL or HDL isolated from APOA1 Tg ;Ldlr −/− mice, and challenged them with lipopolysaccharide. Transcriptional profiling showed that HDL exerts a broad anti-inflammatory effect on lipopolysaccharide-induced genes and proinflammatory effect in a subset of genes enriched for chemokines. Cholesterol removal by POPC (1-palmitoyl-2-oleoyl-glycero-3-phosphocholine) liposomes or β-methylcyclodextrin mimicked both pro- and anti-inflammatory effects of HDL, whereas cholesterol loading by POPC/cholesterol-liposomes or acetylated LDL (low-density lipoprotein) before HDL attenuated these effects, indicating that these responses are mediated by cholesterol efflux. While early anti-inflammatory effects reflect reduced TLR (Toll-like receptor) 4 levels, late anti-inflammatory effects are due to reduced IFN (interferon) receptor signaling. Proinflammatory effects occur late and represent a modified endoplasmic reticulum stress response, mediated by IRE1a (inositol-requiring enzyme 1a)/ASK1 (apoptosis signal-regulating kinase 1)/p38 MAPK (p38 mitogen-activated protein kinase) signaling, that occurs under conditions of extreme cholesterol depletion. To investigate the effects of HDL on inflammatory gene expression in myeloid cells in atherosclerotic lesions, we injected reconstituted HDL into Apoe −/− or Ldlr −/− mice fed a Western-type diet. Reconstituted HDL infusions produced anti-inflammatory effects in lesion macrophages without any evidence of proinflammatory effects. Conclusions: Reconstituted HDL infusions in hypercholesterolemic atherosclerotic mice produced anti-inflammatory effects in lesion macrophages suggesting a beneficial therapeutic effect of HDL in vivo.

scholarly journals ADAM17 Boosts Cholesterol Efflux and Downstream Effects of High-Density Lipoprotein on Inflammatory Pathways in Macrophages

2021 ◽  
Author(s):  
Vishal Kothari ◽  
Jingjing Tang ◽  
Yi He ◽  
Farah Kramer ◽  
Jenny E. Kanter ◽  
...  
Keyword(s):  
High Density Lipoprotein ◽  
Cholesterol Efflux ◽  
Density Lipoprotein ◽  
Myeloid Cell ◽  
Peritoneal Macrophages ◽  
High Density ◽  
Cholesterol Depletion ◽  
Proinflammatory Responses ◽  
Anti Inflammatory

Objective: HDL (high-density lipoprotein) can exert both anti-inflammatory and proinflammatory effects in macrophages due to its ability to induce cholesterol depletion. Because cholesterol depletion also increases sheddase activity of the membrane protease ADAM17 (ADAM metallopeptidase domain 17) in other cells, we examined if ADAM17 plays a role in HDL’s effects on inflammatory processes in macrophages in vitro and in vivo. Approach and Results: Sorted peritoneal macrophages from human APOA1 (apolipoprotein A1) transgenic LDL (low-density lipoprotein) receptor-deficient ( APOA1 Tg ; Ldlr −/− ) mice with and without myeloid cell-targeted ADAM17-deficiency were studied in parallel with wildtype and ADAM17-deficient bone marrow-derived macrophages stimulated with HDL in vitro. HDL increased ADAM17 expression and activity in macrophages. Furthermore, ADAM17-deficient macrophages exhibited reduced expression of ABCA1 (ATP-binding cassette A1) and reduced cholesterol efflux and were cholesterol loaded. This was caused by the absence of shedding of TNFα, a major ADAM17 substrate. Sorted thioglycollate-elicited peritoneal macrophages freshly isolated from APOA1 Tg ; Ldlr −/− mice, which have higher HDL levels than Ldlr −/− controls, showed reduced expression of interferon-inducible genes in response to lipopolysaccharide or interferon-β, but exacerbated proinflammatory responses to lipopolysaccharide for Tnfa , Cxcl1 , Ccl2 , and Il1b , phenocopying cells stimulated with HDL in vitro. These effects were all prevented in ADAM17-deficient macrophages and associated with lower concentrations of large HDL particles in APOA1 Tg ; Ldlr −/− mice with myeloid cell-targeted ADAM17-deficiency. Conclusions: The increased cholesterol loading of ADAM17-deficient macrophages prevents both anti-inflammatory and proinflammatory responses of HDL. Our findings demonstrate a novel role for ADAM17 in maintaining cholesterol efflux in macrophages, thereby regulating the immune functions of these cells.

scholarly journals Anti-inflammatory effect of high-density lipoprotein on the cardiovascular system of hyperlipidemic mice

2011 ◽  
Vol 30 (10) ◽  
pp. 763-769
Author(s):  
José Antonio D. Garcia ◽  
Ciderléia Castro de Lima ◽  
Luiza B. Messora ◽  
Aline F. Cruz ◽  
Ana P.S. Marques ◽  
...  
Keyword(s):  
High Density Lipoprotein ◽  
Cardiovascular System ◽  
Density Lipoprotein ◽  
High Density ◽  
Anti Inflammatory ◽  
Inflammatory Effect

scholarly journals Anti-Inflammatory Properties of High Density Lipoprotein (HDL) on Intestinal Epithelial Cells

2011 ◽  
Vol 140 (5) ◽  
pp. S-838
Author(s):  
Ragam Attinkara ◽  
Lucia Rohrer ◽  
Gerd A. Kullak-Ublick ◽  
Gerhard Rogler ◽  
Jyrki J. Eloranta
Keyword(s):  
Epithelial Cells ◽  
High Density Lipoprotein ◽  
Intestinal Epithelial Cells ◽  
Density Lipoprotein ◽  
High Density ◽  
Intestinal Epithelial ◽  
Anti Inflammatory

P151 DISRUPTION OF ENDOGENOUS ITACONATE PRODUCTION EXACERBATES EXPERIMENTAL COLITIS

2020 ◽  
Vol 26 (Supplement_1) ◽  
pp. S5-S6
Author(s):  
Ryan Frieler ◽  
Thomas Vigil ◽  
Richard Mortensen ◽  
Yatrik Shah
Keyword(s):  
Gene Expression ◽  
Immune Cell ◽  
Tricarboxylic Acid Cycle ◽  
Myeloid Cells ◽  
Experimental Colitis ◽  
Cell Types ◽  
Cell Phenotype ◽  
Inflammatory Gene Expression ◽  
Inflammatory Gene ◽  
Anti Inflammatory

Abstract Background Inflammation is a hallmark of inflammatory bowel disease and alterations in tricarboxylic acid cycle (TCA) metabolism have been identified as major regulators of immune cell phenotype during inflammation and hypoxia. The TCA cycle metabolite, itaconate, is produced by the enzyme aconitate decarboxylase 1 (Acod1) and is highly upregulated during classical macrophage activation and during experimental colitis. Itaconate and cell permeable derivatives have robust anti-inflammatory effects on macrophages, therefore we hypothesized that Acod1-produced itaconate has a protective, anti-inflammatory effect during experimental colitis. Methods and Results Wild type (WT) control and Acod1-/- mice were administered 3% Dextran Sulfate Sodium (DSS) in water for 7 days to induce experimental colitis. After DSS was discontinued, Acod1-/- mice had significantly reduced body weight recovery with increased macroscopic disease severity, and upon dissection had decreased colon length and more severe inflammation. To determine if myeloid cells are the critical Acod1/itaconate-producing cell types, we generated myeloid-specific Acod1 deficient mice, however no differences in weight loss, colon length or inflammatory gene expression were detected compared to WT controls. To test whether supplementation with exogenous itaconate could ameliorate colitis, WT mice were treated with the cell-permeable form of itaconate, dimethyl itaconate (DMI). Administration of DMI significantly improved recovery after 7 days of DSS treatment and significantly reduced inflammatory gene expression in the colon. Conclusion Our data suggest that Acod1-produced itaconate has an important role in the regulation of inflammation during experimental colitis. Although myeloid cells have been thought to be major producers of Acod1 and itaconate, our data indicate that other cell types are involved. These results highlight the importance of this immunometabolic pathway and suggest that preservation or enhancement of this pathway with natural metabolites or metabolite derivatives could have beneficial effects during colitis.

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