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Huang P, Ran J, Zhu W, Dai W, Tang Y, Lian P, Huang X, Li R. PCSK9 dysregulates cholesterol homeostasis and triglyceride metabolism in olanzapine-induced hepatic steatosis via both receptor-dependent and receptor-independent pathways. FASEB J 2024; 38:e23464. [PMID: 38358343 DOI: 10.1096/fj.202301748r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 01/06/2024] [Accepted: 01/22/2024] [Indexed: 02/16/2024]
Abstract
Schizophrenia, affecting approximately 1% of the global population, is often treated with olanzapine. Despite its efficacy, olanzapine's prolonged use has been associated with an increased risk of cardiovascular diseases and nonalcoholic fatty liver disease (NAFLD); however, the underlying mechanism remains unclear. Proprotein convertase subtilisin kexin type 9 (PCSK9) plays a crucial role in lipid metabolism and is involved in NAFLD pathogenesis via an unknown mechanism. This study aims to investigate the role of PCSK9 in olanzapine-induced NAFLD. C57BL/6J mice and HepG2 and AML12 cell lines were treated with varying concentrations of olanzapine to examine the effects of olanzapine on PCSK9 and lipid metabolism. PCSK9 levels were manipulated using recombinant proteins, plasmids, and small interfering RNAs in vitro, and the effects on hepatic lipid accumulation and gene expression related to lipid metabolism were assessed. Olanzapine treatment significantly increased PCSK9 levels in both animal and cell line models, correlating with elevated lipid accumulation. PCSK9 manipulation demonstrated its central role in mediating hepatic steatosis through both receptor-dependent pathways (impacting NPC1L1) and receptor-independent pathways (affecting lipid synthesis, uptake, and cholesterol biosynthesis). Interestingly, upregulation of SREBP-1c, rather than SREBP-2, was identified as a key driver of PCSK9 increase in olanzapine-induced NAFLD. Our findings establish PCSK9 as a pivotal factor in olanzapine-induced NAFLD, influencing both receptor-related and metabolic pathways. This highlights PCSK9 inhibitors as potential therapeutic agents for managing NAFLD in schizophrenia patients treated with olanzapine.
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Affiliation(s)
- Piaopiao Huang
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Juanli Ran
- Department of Stomatology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Wenqiang Zhu
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Wen Dai
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
- Department of Medicine, Columbia University Medical Center, New York, New York, USA
| | - Yaxin Tang
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Pingan Lian
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xiansheng Huang
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Rong Li
- Department of Stomatology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
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Zhang J, Liu G, Liu Y, Yang P, Xie J, Wei X. The biological functions and related signaling pathways of SPON2. Front Oncol 2024; 13:1323744. [PMID: 38264743 PMCID: PMC10803442 DOI: 10.3389/fonc.2023.1323744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 12/20/2023] [Indexed: 01/25/2024] Open
Abstract
Spondin-2 (SPON2), also referred to as M-spondin or DIL-1, is a member of the extracellular matrix protein family known as Mindin-F-spondin (FS). SPON2 can be used as a broad-spectrum tumor marker for more than a dozen tumors, mainly prostate cancer. Meanwhile, SPON2 is also a potential biomarker for the diagnosis of certain non-tumor diseases. Additionally, SPON2 plays a pivotal role in regulating tumor metastasis and progression. In normal tissues, SPON2 has a variety of biological functions represented by promoting growth and development and cell proliferation. This paper presents a comprehensive overview of the regulatory mechanisms, diagnostic potential as a broad-spectrum biomarker, diverse biological functions, involvement in various signaling pathways, and clinical applications of SPON2.
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Affiliation(s)
- Jingrun Zhang
- Zhongshan Clinical College, Dalian University, Dalian, China
- Laboratory of Orthopedics, Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Ge Liu
- Laboratory of Orthopedics, Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Yuchen Liu
- Zhongshan Clinical College, Dalian University, Dalian, China
| | - Pei Yang
- Department of Neurology, The Third Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Junyuan Xie
- Department of Breast Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xiaowei Wei
- Laboratory of Orthopedics, Affiliated Zhongshan Hospital of Dalian University, Dalian, China
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Identification of Monocyte-Associated Genes Related to the Instability of Atherosclerosis Plaque. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:3972272. [PMID: 36187340 PMCID: PMC9519342 DOI: 10.1155/2022/3972272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/05/2022] [Accepted: 08/12/2022] [Indexed: 11/17/2022]
Abstract
Background. Atherosclerotic plaque instability is a common cause of stroke and ischemic infarction, and identification of monocyte-associated genes has become a prominent feature in cardiovascular research as a contributing/predictive marker. Methods. Whole genome sequencing data were downloaded from GSE159677, GSE41571, GSE120521, and GSE118481. Single-cell sequencing data analysis was conducted to cluster molecular subtypes of atherosclerotic plaques and identify specific genes. Differentially expressed genes (DEGs) between normal subjects and patients with unstable atheromatous plaques were screened. Weighted gene coexpression network analysis (WGCNA) was performed to find key module genes. In addition, GO and KEGG enrichment analyses explored potential biological signaling pathways to generate protein interaction (PPI) networks. GSEA and GSVA demonstrated activations in plaque instability subtypes. Results. 239 monocyte-associated genes were identified based on bulk and single-cell RNA-sequencing, followed by the recognition of 1221 atherosclerotic plaque-associated DEGs from the pooled matrix. GO and KEGG analyses suggested that DEGs might be related to inflammation response and the PI3K-Akt signaling pathway. Eight no-grey modules were obtained through WGCNA analysis, and the turquoise module has the highest correlation with unstable plaque (
), which contained 1323 module genes. After fetching the intersecting genes, CXCL3, FPR1, GK, and LST1 were obtained that were significantly associated with plaque instability, which had an intense specific interaction. Monocyte-associated genes associated with atherosclerotic plaque instability have certain diagnostic significance and are generally overexpressed in this patient population. In addition, 11 overlapping coexpressed genes (CEG) might also activated multiple pathways regulating inflammatory responses, platelet activation, and hypoxia-inducible factors. GSVA showed that the corresponding pathways were significantly activated in high expression samples. Conclusions. Overexpression of CXCL3, GK, FPR1, and LST1 was advanced recognition and intervention factors for unstable plaques, which might become targets for atherosclerosis rupture prevention. We also analyzed the potential mechanisms of CEG from inflammatory and oxidative stress pathways.
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Wei S, Zhang L, Bailu Wang, Zhao Y, Dong Q, Pan C, Li C, He D, Yuan Q, Xu F, Chen Y. ALDH2 deficiency inhibits Ox-LDL induced foam cell formation via suppressing CD36 expression. Biochem Biophys Res Commun 2019; 512:41-48. [PMID: 30853183 DOI: 10.1016/j.bbrc.2019.02.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Accepted: 02/02/2019] [Indexed: 12/31/2022]
Abstract
Foam cell formation plays an important role in the initiation and progression of atherosclerosis. Aldehyde dehydrogenase 2 (ALDH2), a key enzyme for aldehyde metabolism, is associated with coronary artery disease and affects atherosclerotic plaque vulnerability. However, the role of ALDH2 in foam cell formation remains unclear. Using peritoneal macrophages from ALDH2-deficient and control mice, we found that ALDH2 deficiency suppressed foam cell formation induced by oxidized low-density lipoproteins (ox-LDL) but not acetylated low-density lipoproteins (ac-LDL) ex vivo. After incubation with ox-LDL, ALDH2-deficient macrophages expressed lower levels of CD36 but the expression of other lipid metabolism-related proteins including SRA, LOX-1, ABCA-1, ABCG-1 and ACAT-1 was not changed in ALDH2-/- macrophages. Using CD36 inhibitor, we confirmed that CD36 contributes to the effect of ALDH2 on foam cell formation. PPARγ was downregulated in ox-LDL treated ALDH2-/- macrophages. 4-HNE was increased by ALDH2 deficiency and high concentration of 4-HNE suppressed the expression of PPARγ. These data suggest that ALDH2 plays an important role in foam cell formation via 4-HNE/PPARγ/CD36 pathway.
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Affiliation(s)
- Shujian Wei
- Department of Emergency, Qilu Hospital, Shandong University, Jinan, China; Chest Pain Center, Qilu Hospital, Shandong University, Jinan, China; Institute of Emergency and Critical Care Medicine, Shandong University, Jinan, China; Key Laboratory of Emergency and Critical Care Medicine of Shandong Province, Qilu Hospital, Shandong University, Jinan, China; Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Public Health, Qilu Hospital, Shandong University, Jinan, China
| | - Luetao Zhang
- Department of Emergency, Qilu Hospital, Shandong University, Jinan, China; Chest Pain Center, Qilu Hospital, Shandong University, Jinan, China; Institute of Emergency and Critical Care Medicine, Shandong University, Jinan, China; Key Laboratory of Emergency and Critical Care Medicine of Shandong Province, Qilu Hospital, Shandong University, Jinan, China; Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Public Health, Qilu Hospital, Shandong University, Jinan, China
| | - Bailu Wang
- Clinical Trial Center, Qilu Hospital, Shandong University, Jinan, China
| | - Yu Zhao
- Department of Emergency, Qilu Hospital, Shandong University, Jinan, China; Chest Pain Center, Qilu Hospital, Shandong University, Jinan, China; Institute of Emergency and Critical Care Medicine, Shandong University, Jinan, China; Key Laboratory of Emergency and Critical Care Medicine of Shandong Province, Qilu Hospital, Shandong University, Jinan, China; Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Public Health, Qilu Hospital, Shandong University, Jinan, China
| | - Qianqian Dong
- Department of Emergency, Qilu Hospital, Shandong University, Jinan, China; Chest Pain Center, Qilu Hospital, Shandong University, Jinan, China; Institute of Emergency and Critical Care Medicine, Shandong University, Jinan, China; Key Laboratory of Emergency and Critical Care Medicine of Shandong Province, Qilu Hospital, Shandong University, Jinan, China; Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Public Health, Qilu Hospital, Shandong University, Jinan, China
| | - Chang Pan
- Department of Emergency, Qilu Hospital, Shandong University, Jinan, China; Chest Pain Center, Qilu Hospital, Shandong University, Jinan, China; Institute of Emergency and Critical Care Medicine, Shandong University, Jinan, China; Key Laboratory of Emergency and Critical Care Medicine of Shandong Province, Qilu Hospital, Shandong University, Jinan, China; Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Public Health, Qilu Hospital, Shandong University, Jinan, China
| | - Chuanbao Li
- Department of Emergency, Qilu Hospital, Shandong University, Jinan, China; Chest Pain Center, Qilu Hospital, Shandong University, Jinan, China; Institute of Emergency and Critical Care Medicine, Shandong University, Jinan, China; Key Laboratory of Emergency and Critical Care Medicine of Shandong Province, Qilu Hospital, Shandong University, Jinan, China; Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Public Health, Qilu Hospital, Shandong University, Jinan, China
| | - Dayu He
- Department of Emergency, Qilu Hospital, Shandong University, Jinan, China; Chest Pain Center, Qilu Hospital, Shandong University, Jinan, China; Institute of Emergency and Critical Care Medicine, Shandong University, Jinan, China; Key Laboratory of Emergency and Critical Care Medicine of Shandong Province, Qilu Hospital, Shandong University, Jinan, China; Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Public Health, Qilu Hospital, Shandong University, Jinan, China
| | - Qiuhuan Yuan
- Department of Emergency, Qilu Hospital, Shandong University, Jinan, China; Chest Pain Center, Qilu Hospital, Shandong University, Jinan, China; Institute of Emergency and Critical Care Medicine, Shandong University, Jinan, China; Key Laboratory of Emergency and Critical Care Medicine of Shandong Province, Qilu Hospital, Shandong University, Jinan, China
| | - Feng Xu
- Department of Emergency, Qilu Hospital, Shandong University, Jinan, China; Chest Pain Center, Qilu Hospital, Shandong University, Jinan, China; Institute of Emergency and Critical Care Medicine, Shandong University, Jinan, China; Key Laboratory of Emergency and Critical Care Medicine of Shandong Province, Qilu Hospital, Shandong University, Jinan, China; Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Public Health, Qilu Hospital, Shandong University, Jinan, China.
| | - Yuguo Chen
- Department of Emergency, Qilu Hospital, Shandong University, Jinan, China; Chest Pain Center, Qilu Hospital, Shandong University, Jinan, China; Institute of Emergency and Critical Care Medicine, Shandong University, Jinan, China; Key Laboratory of Emergency and Critical Care Medicine of Shandong Province, Qilu Hospital, Shandong University, Jinan, China; Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Public Health, Qilu Hospital, Shandong University, Jinan, China.
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Yao Y, Liu T, Wang X, Zhang D. The Contrary Effects of Sirt1 on MCF7 Cells Depend on CD36 Expression Level. J Surg Res 2019; 238:248-254. [PMID: 30826489 DOI: 10.1016/j.jss.2019.01.046] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Revised: 11/16/2018] [Accepted: 01/17/2019] [Indexed: 11/30/2022]
Abstract
BACKGROUND Breast cancer is one of the most aggressive and pervasive cancers identified in females. Sirt1 and CD36 both exert an essential role toward the oncogenic signaling in breast cancer cells. As reported, the adrenergic signaling could promote the malignancy of breast cancer. This study focuses specifically on the role of Sirt1/CD36 in the proliferation of MCF-7 breast cancer cells and also investigates their response to the α2-adrenergic agonist dexmedetomidine (Dex). MATERIALS AND METHODS Expression of Sirt1 and CD36 was measured in breast cancer tissue by immunohistochemistry. We cultured MCF7 cells and treated cells with resveratrol (RSV) or Dex. Western blot analysis was performed to quantify the protein expression levels. The methyl thiazolyl tetrazolium (MTT) assay was applied to detect cell proliferation. RESULTS Compared with normal adjacent tissues, Sirt1 increased and CD36 decreased in cancer tissues. RSV, a Sirt1 activator, increased the proliferation of MCF-7 cells at low concentration but exerted cytotoxicity effect at higher concentration. Sirt1 activation increased the expression of CD36 at higher concentration. Dex treatment gradually increased the proliferation of MCF7 cells in a dose-dependent manner and downregulated the expression of Sirt1/CD36. Interestingly, overexpression of Sirt1 via RSV pretreatment could suppress Dex-stimulated proliferation of breast cancer, accompanied with CD36 upregulation. CONCLUSIONS though expression of Sirt1 increased in breast cancer progression, overexpression of Sirt1 could inhibit MCF7 proliferation, which may be associated with CD36 upregulation. In addition, the promotion effect of Dex on MCF7 cells, which may be associated with the Sirt1/CD36 inhibition, could be weakened by Sirt1 activation via RSV.
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Affiliation(s)
- Yiqun Yao
- Department of Thyroid and Breast Surgery, the Affiliated Zhongshan Hospital of Dalian University, Dalian, Liaoning, China
| | - Tao Liu
- Department of Thyroid and Breast Surgery, the Affiliated Zhongshan Hospital of Dalian University, Dalian, Liaoning, China
| | - Xiaolan Wang
- Department of Thyroid and Breast Surgery, the Affiliated Zhongshan Hospital of Dalian University, Dalian, Liaoning, China
| | - Dianlong Zhang
- Department of Thyroid and Breast Surgery, the Affiliated Zhongshan Hospital of Dalian University, Dalian, Liaoning, China.
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Han L, Wang YL, Sun YC, Hu ZY, Hu K, Du LB. tert-Butylhydroperoxide induces apoptosis in RAW264.7 macrophages via a mitochondria-mediated signaling pathway. Toxicol Res (Camb) 2018; 7:970-976. [PMID: 30310674 DOI: 10.1039/c7tx00282c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 05/22/2018] [Indexed: 01/17/2023] Open
Abstract
Macrophage apoptosis occurs throughout all stages of atherosclerosis, mainly induced by oxidized low density lipoproteins (Ox LDLs), leading to the formation of necrotic cores. Nevertheless, the mechanism of macrophage apoptosis induced by Ox LDLs is not yet clearly understood. In this study, a model of RAW264.7 macrophages exposed to an Ox LDL analogue, i.e. tert-butylhydroperoxide (t-BHP), was established. We thoroughly evaluated the viability and apoptosis of RAW264.7 cells treated with t-BHP at different time intervals. t-BHP treatment decreases the viability of RAW264.7 cells in a dose- and time-dependent manner (IC50: 400 μM) and also induces a loss of the mitochondrial membrane potential (MMP) in RAW264.7 cells. Moreover, the activation of Bid, up-regulation of Bcl-2, and down-regulation of Bax, as well as the proteolysis of pro-caspase 3 and cleavage of PARP, were all also observed in t-BHP treated RAW264.7 cells. Finally, we concluded that t-BHP induces the apoptosis of macrophages via a mitochondria-mediated signaling pathway.
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Affiliation(s)
- Lu Han
- Beijing Engineering Research Center of Printed Electronics , Beijing Institute of Graphic Communication , Beijing 102600 , PR China .
| | - Yu-Long Wang
- Beijing Engineering Research Center of Printed Electronics , Beijing Institute of Graphic Communication , Beijing 102600 , PR China .
| | - Yan-Chi Sun
- Beijing Engineering Research Center of Printed Electronics , Beijing Institute of Graphic Communication , Beijing 102600 , PR China .
| | - Zi-Yuan Hu
- Beijing Engineering Research Center of Printed Electronics , Beijing Institute of Graphic Communication , Beijing 102600 , PR China .
| | - Kun Hu
- Beijing Engineering Research Center of Printed Electronics , Beijing Institute of Graphic Communication , Beijing 102600 , PR China .
| | - Li-Bo Du
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species , Center for Molecular Science , Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , PR China
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Huangfu N, Wang Y, Cheng J, Xu Z, Wang S. Metformin protects against oxidized low density lipoprotein-induced macrophage apoptosis and inhibits lipid uptake. Exp Ther Med 2018; 15:2485-2491. [PMID: 29456653 PMCID: PMC5795518 DOI: 10.3892/etm.2018.5704] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 12/28/2017] [Indexed: 12/31/2022] Open
Abstract
Oxidized low density lipoprotein (ox-LDL)-induced macrophage apoptosis contributes to the formation of atherosclerosis. Metformin, an antidiabetic drug, has been reported to attenuate lipid accumulation in macrophages. In this study, the effects of metformin on ox-LDL-induced macrophage apoptosis were investigated and the mechanisms involved in this process were examined. By performing flow cytometry analysis, it was demonstrated that metformin inhibited ox-LDL-induced macrophage apoptosis. Increased expression of endoplasmic reticulum (ER) stress marker proteins, including C/EBP-homologous protein, eukaryotic translation initiation factor 2A, and glucose-regulated protein 78 kDa, induced by ox-LDL was also reversed by metformin. Furthermore, ox-LDL-induced cytochrome c (cyto-c) release and mitochondrial membrane potential loss were inhibited by metformin. As lipid uptake in macrophages contributed to ER stress, cyto-c release and mitochondrial membrane potential loss, the mechanisms involved in metformin-inhibited macrophage lipid uptake were investigated. Expression of scavenger receptors, including scavenger receptor A, cluster of differentiation 36 and lectin-type oxidized LDL receptor 1 was examined in the presence or absence of metformin with ox-LDL treatment. Additionally, the upstream regulatory mechanism of scavenger receptors by metformin was also analyzed. In conclusion, metformin protects against ox-LDL-induced macrophage apoptosis and inhibits macrophage lipid uptake.
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Affiliation(s)
- Ning Huangfu
- Department of Cardiology, Ningbo First Hospital, Ningbo, Zhejiang 315010, P.R. China
| | - Yong Wang
- Department of Cardiology, Ningbo First Hospital, Ningbo, Zhejiang 315010, P.R. China
| | - Jingsong Cheng
- Department of Cardiology, Ningbo First Hospital, Ningbo, Zhejiang 315010, P.R. China
| | - Zhenyu Xu
- Department of Cardiology, Ningbo First Hospital, Ningbo, Zhejiang 315010, P.R. China
| | - Shenghuang Wang
- Department of Cardiology, Ningbo First Hospital, Ningbo, Zhejiang 315010, P.R. China
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Jongstra-Bilen J, Zhang CX, Wisnicki T, Li MK, White-Alfred S, Ilaalagan R, Ferri DM, Deonarain A, Wan MH, Hyduk SJ, Cummins CL, Cybulsky MI. Oxidized Low-Density Lipoprotein Loading of Macrophages Downregulates TLR-Induced Proinflammatory Responses in a Gene-Specific and Temporal Manner through Transcriptional Control. THE JOURNAL OF IMMUNOLOGY 2017; 199:2149-2157. [PMID: 28784845 DOI: 10.4049/jimmunol.1601363] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 07/16/2017] [Indexed: 01/08/2023]
Abstract
Hypercholesterolemia is a key risk factor for atherosclerosis and leads to the uptake of native and oxidized low-density lipoprotein (oxLDL) by macrophages (Mϕs) and foam cell formation. Inflammatory processes accompany Mϕ foam cell formation in the artery wall, yet the relationship between Mϕ lipid loading and their response to inflammatory stimuli remains elusive. We investigated proinflammatory gene expression in thioglycollate-elicited peritoneal Mϕs, bone marrow-derived Mϕs and dendritic cells, and RAW264.7 cells. Loading with oxLDL did not induce peritoneal Mϕ apoptosis or modulate basal-level expression of proinflammatory genes. Upon stimulation of TLR4, the rapid induction of IFN-β was inhibited in cells loaded with oxLDL, whereas the induction of other proinflammatory genes by TLR4 (LPS), TLR3 (polyriboinosinic-polyribocytidylic acid), TLR2 (Pam3CSK4), and TLR9 (CpG) remained comparable within the first 2 h. Subsequently, the expression of a subset of proinflammatory genes (e.g., IL-1β, IL-6, CCL5) was reduced in oxLDL-loaded cells at the level of transcription. This phenomenon was partially dependent on NF erythroid 2-related factor 2 (NRF2) but not on nuclear liver X receptors α and β (LXRα,β), peroxisome proliferator-activated receptor-γ (PPARγ), and activating transcription factor 3 (ATF3). LPS-induced NF-κB reporter activity and intracellular signaling by NF-κB and MAPK pathways were comparable in oxLDL-loaded Mϕs, yet the binding of p65/RelA (the prototypic NF-κB family member) was reduced at IL-6 and CCL5 promoters. This study revealed that oxLDL loading of Mϕs negatively regulates transcription at late stages of TLR-induced proinflammatory gene expression and implicates epigenetic mechanisms such as histone deacetylase activity.
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Affiliation(s)
- Jenny Jongstra-Bilen
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada; .,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Department of Immunology, University of Toronto, Toronto, Ontario M5S 1A8, Canada; and
| | - Cindy X Zhang
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada.,Department of Immunology, University of Toronto, Toronto, Ontario M5S 1A8, Canada; and
| | - Timothy Wisnicki
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada.,Department of Immunology, University of Toronto, Toronto, Ontario M5S 1A8, Canada; and
| | - Mengyi K Li
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Samantha White-Alfred
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - Ragave Ilaalagan
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Dario M Ferri
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada.,Department of Immunology, University of Toronto, Toronto, Ontario M5S 1A8, Canada; and
| | - Ashley Deonarain
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada.,Department of Immunology, University of Toronto, Toronto, Ontario M5S 1A8, Canada; and
| | - Mark H Wan
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - Sharon J Hyduk
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - Carolyn L Cummins
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
| | - Myron I Cybulsky
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Department of Immunology, University of Toronto, Toronto, Ontario M5S 1A8, Canada; and
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