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Bai X, Wang S, Shu L, Cao Q, Hu H, Zhu Y, Chen C. Hawthorn leaf flavonoids alleviate the deterioration of atherosclerosis by inhibiting SCAP-SREBP2-LDLR pathway through sPLA2-ⅡA signaling in macrophages in mice. JOURNAL OF ETHNOPHARMACOLOGY 2024; 327:118006. [PMID: 38442806 DOI: 10.1016/j.jep.2024.118006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/23/2024] [Accepted: 03/01/2024] [Indexed: 03/07/2024]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Hawthorn leaves are a combination of the dried leaves of the Rosaceae plants, i.e., Crataegus pinnatifida Bge. or Crataegus pinnatifida Bge. var. major N. E. Br., is primarily cultivated in East Asia, North America, and Europe. hawthorn leaf flavonoids (HLF) are the main part of extraction. The HLF have demonstrated potential in preventing hypertension, inflammation, hyperlipidemia, and atherosclerosis. However, the potential pharmacological mechanism behind its anti-atherosclerotic effect has yet to be explored. AIM OF THE STUDY The in vivo and in vitro effects of HLF on lipid-mediated foam cell formation were investigated, with a specific focus on the levels of secreted phospholipase A2 type IIA (sPLA2-II A) in macrophage cells. MATERIALS AND METHODS The primary constituents of HLF were analyzed using ultra-high performance liquid chromatography and liquid chromatography-tandem mass spectrometry. In vivo, HLF, at concentrations of 5 mg/kg, 20 mg/kg, and 40 mg/kg, were administered to apolipoprotein E knockout mice (ApoE-/-) fed by high-fat diet (HFD) for 16 weeks. Aorta and serum samples were collected to identify lesion areas and lipids through mass spectrometry analysis to dissect the pathological process. RAW264.7 cells were incubated with oxidized low-density lipoprotein (ox-LDL) alone, or ox-LDL combined with different doses of HLF (100, 50, and 25 μg/ml), or ox-LDL plus 24-h sPLA2-IIA inhibitors, for cell biology analysis. Lipids and inflammatory cytokines were detected using biochemical analyzers and ELISA, while plaque size and collagen content of plaque were assessed by HE and the Masson staining of the aorta. The lipid deposition in macrophages was observed by Oil Red O staining. The expression of sPLA2-IIA and SCAP-SREBP2-LDLR was determined by RT-qPCR and Western blot analysis. RESULTS The chemical profile of HLF was studied using UPLC-Q-TOF-MS/MS, allowing the tentative identification of 20 compounds, comprising 1 phenolic acid, 9 flavonols and 10 flavones, including isovitexin, vitexin-4″-O-glucoside, quercetin-3-O-robibioside, rutin, vitexin-2″-O-rhamnoside, quercetin, etc. HLF decreased total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and non-high-density lipoprotein cholesterol (non-HDL-C) levels in ApoE-/- mice (P < 0.05), reduced ox-LDL uptake, inhibited level of inflammatory factors, such as IL-6, IL-8, TNF-α, and IL-1ꞵ (P < 0.001), and alleviated aortic plaques with a thicker fibrous cap. HLF effectively attenuated foam cell formation in ox-LDL-treated RAW264.7 macrophages, and reduced levels of intracellular TC, free cholesterol (FC), cholesteryl ester (CE), IL-6, TNF-α, and IL-1β (P < 0.001). In both in vivo and in vitro experiments, HLF significantly downregulated the expression of sPLA2-IIA, SCAP, SREBP2, LDLR, HMGCR, and LOX-1 (P < 0.05). Furthermore, sPLA2-IIA inhibitor effectively mitigated inflammatory release in RAW264.7 macrophages and regulated SCAP-SREBP2-LDLR signaling pathway by inhibiting sPLA2-IIA secretion (P < 0.05). CONCLUSION HLF exerted a protective effect against atherosclerosis through inhibiting sPLA2-IIA to diminish SCAP-SREBP2-LDLR signaling pathway, to reduce LDL uptake caused foam cell formation, and to slow down the progression of atherosclerosis in mice.
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Affiliation(s)
- Xufeng Bai
- College of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, 330004, China
| | - Shuwen Wang
- College of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, 330004, China
| | - Limei Shu
- College of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, 330004, China
| | - Qingyu Cao
- College of Pharmacy, Nanchang Medical College, Nanchang, Jiangxi, 330052, China
| | - Huiming Hu
- College of Pharmacy, Nanchang Medical College, Nanchang, Jiangxi, 330052, China; Key Laboratory of Pharmacodynamics and Quality Evaluation on Anti-Inflammatory Chinese Herbs, Jiangxi Administration of Traditional Chinese Medicine, Jiangxi, 330052, China; School of Biomedical Sciences, University of Queensland, St Lucia, Brisbane, Queensland, 4072, Australia.
| | - Yanchen Zhu
- College of Computer Science, Jiangxi University of Chinese Medicine, Nanchang, Jiangxi, 330004, China.
| | - Chen Chen
- School of Biomedical Sciences, University of Queensland, St Lucia, Brisbane, Queensland, 4072, Australia.
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Butcko AJ, Putman AK, Mottillo EP. The Intersection of Genetic Factors, Aberrant Nutrient Metabolism and Oxidative Stress in the Progression of Cardiometabolic Disease. Antioxidants (Basel) 2024; 13:87. [PMID: 38247511 PMCID: PMC10812494 DOI: 10.3390/antiox13010087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 12/06/2023] [Accepted: 01/07/2024] [Indexed: 01/23/2024] Open
Abstract
Cardiometabolic disease (CMD), which encompasses metabolic-associated fatty liver disease (MAFLD), chronic kidney disease (CKD) and cardiovascular disease (CVD), has been increasing considerably in the past 50 years. CMD is a complex disease that can be influenced by genetics and environmental factors such as diet. With the increased reliance on processed foods containing saturated fats, fructose and cholesterol, a mechanistic understanding of how these molecules cause metabolic disease is required. A major pathway by which excessive nutrients contribute to CMD is through oxidative stress. In this review, we discuss how oxidative stress can drive CMD and the role of aberrant nutrient metabolism and genetic risk factors and how they potentially interact to promote progression of MAFLD, CVD and CKD. This review will focus on genetic mutations that are known to alter nutrient metabolism. We discuss the major genetic risk factors for MAFLD, which include Patatin-like phospholipase domain-containing protein 3 (PNPLA3), Membrane Bound O-Acyltransferase Domain Containing 7 (MBOAT7) and Transmembrane 6 Superfamily Member 2 (TM6SF2). In addition, mutations that prevent nutrient uptake cause hypercholesterolemia that contributes to CVD. We also discuss the mechanisms by which MAFLD, CKD and CVD are mutually associated with one another. In addition, some of the genetic risk factors which are associated with MAFLD and CVD are also associated with CKD, while some genetic risk factors seem to dissociate one disease from the other. Through a better understanding of the causative effect of genetic mutations in CMD and how aberrant nutrient metabolism intersects with our genetics, novel therapies and precision approaches can be developed for treating CMD.
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Affiliation(s)
- Andrew J. Butcko
- Hypertension and Vascular Research Division, Henry Ford Hospital, 6135 Woodward Avenue, Detroit, MI 48202, USA; (A.J.B.); (A.K.P.)
- Department of Physiology, Wayne State University, 540 E. Canfield Street, Detroit, MI 48202, USA
| | - Ashley K. Putman
- Hypertension and Vascular Research Division, Henry Ford Hospital, 6135 Woodward Avenue, Detroit, MI 48202, USA; (A.J.B.); (A.K.P.)
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 784 Wilson Road, East Lansing, MI 48823, USA
| | - Emilio P. Mottillo
- Hypertension and Vascular Research Division, Henry Ford Hospital, 6135 Woodward Avenue, Detroit, MI 48202, USA; (A.J.B.); (A.K.P.)
- Department of Physiology, Wayne State University, 540 E. Canfield Street, Detroit, MI 48202, USA
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3
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Chen JS, Xie PF, Feng H. The role of exercise in improving hyperlipidemia-renal injuries induced by a high-fat diet: a literature review. PeerJ 2023; 11:e15435. [PMID: 37283893 PMCID: PMC10239619 DOI: 10.7717/peerj.15435] [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: 02/14/2023] [Accepted: 04/27/2023] [Indexed: 06/08/2023] Open
Abstract
A diet that is high in sugar and fat is a precursor to various chronic diseases, especially hyperlipidemia. Patients with hyperlipidemia have increased levels of plasma free fatty acids and an ectopic accumulation of lipids. The kidney is one of the main organs affected by this disease and, recently, there have been more studies conducted on renal injury caused by hyperlipidemia. The main pathological mechanism is closely related to renal lipotoxicity. However, in different kidney cells, the reaction mechanism varies due to the different affinities of the lipid receptors. At present, it is believed that in addition to lipotoxicity, hyperlipidemia induced-renal injury is also closely related to oxidative stress, endoplasmic reticulum stress, and inflammatory reactions, which are the result of multiple factors. Exercise plays an important role in the prevention of various chronic diseases and recently emerging researches indicated its positive effects to renal injury caused by hyperlipidemia. However, there are few studies summarizing the effects of exercise on this disease and the specific mechanisms need to be further explored. This article summarizes the mechanisms of hyperlipidemia induced-renal injury at the cellular level and discusses the ways in which exercise may regulate it. The results provide theoretical support and novel approaches for identifying the intervention target to treat hyperlipidemia induced-renal injury.
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Affiliation(s)
- Jun Shunzi Chen
- Institute of Exercise and Health, Tianjin University of Sport, Tianjin, Tianjin, China
- Institute of Physical Education, Guiyang University, Guiyang, Guizhou, China
| | - Peng Fei Xie
- Guizhou Institute of Sports Science, Guiyang, Guizhou, China
| | - Hong Feng
- Institute of Exercise and Health, Tianjin University of Sport, Tianjin, Tianjin, China
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Abstract
Finding new therapeutic targets of glomerulosclerosis treatment is an ongoing quest. Due to a living environment of various stresses and pathological stimuli, podocytes are prone to injuries; moreover, as a cell without proliferative potential, loss of podocytes is vital in the pathogenesis of glomerulosclerosis. Thus, sufficient understanding of factors and underlying mechanisms of podocyte injury facilitates the advancement of treating and prevention of glomerulosclerosis. The clinical symptom of podocyte injury is proteinuria, sometimes with loss of kidney functions progressing to glomerulosclerosis. Injury-induced changes in podocyte physiology and function are actually not a simple passive process, but a complex interaction of proteins that comprise the anatomical structure of podocytes at molecular levels. This chapter lists several aspects of podocyte injuries along with potential mechanisms, including glucose and lipid metabolism disorder, hypertension, RAS activation, micro-inflammation, immune disorder, and other factors. These aspects are not technically separated items, but intertwined with each other in the pathogenesis of podocyte injuries.
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Chami B, Hossain F, Hambly TW, Cai X, Aran R, Fong G, Vellajo A, Martin NJJ, Wang X, Dennis JM, Sharma A, Shihata WA, Chin-Dusting JPF, de Haan JB, Sharland A, Geczy CL, Freedman B, Witting PK. Serum Amyloid A Stimulates Vascular and Renal Dysfunction in Apolipoprotein E-Deficient Mice Fed a Normal Chow Diet. Front Immunol 2019; 10:380. [PMID: 30899260 PMCID: PMC6416175 DOI: 10.3389/fimmu.2019.00380] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 02/14/2019] [Indexed: 12/19/2022] Open
Abstract
Elevated serum amyloid A (SAA) levels may promote endothelial dysfunction, which is linked to cardiovascular and renal pathologies. We investigated the effect of SAA on vascular and renal function in apolipoprotein E-deficient (ApoE−/−) mice. Male ApoE−/− mice received vehicle (control), low-level lipopolysaccharide (LPS), or recombinant human SAA by i.p. injection every third day for 2 weeks. Heart, aorta and kidney were harvested between 3 days and 18 weeks after treatment. SAA administration increased vascular cell adhesion molecule (VCAM)-1 expression and circulating monocyte chemotactic protein (MCP)-1 and decreased aortic cyclic guanosine monophosphate (cGMP), consistent with SAA inhibiting nitric oxide bioactivity. In addition, binding of labeled leukocytes to excised aorta increased as monitored using an ex vivo leukocyte adhesion assay. Renal injury was evident 4 weeks after commencement of SAA treatment, manifesting as increased plasma urea, urinary protein, oxidized lipids, urinary kidney injury molecule (KIM)-1 and multiple cytokines and chemokines in kidney tissue, relative to controls. Phosphorylation of nuclear-factor-kappa-beta (NFκB-p-P65), tissue factor (TF), and macrophage recruitment increased in kidneys from ApoE−/− mice 4 weeks after SAA treatment, confirming that SAA elicited a pro-inflammatory and pro-thrombotic phenotype. These data indicate that SAA impairs endothelial and renal function in ApoE−/− mice in the absence of a high-fat diet.
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Affiliation(s)
- Belal Chami
- Discipline of Pathology, Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
| | - Farjaneh Hossain
- Discipline of Pathology, Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
| | - Thomas W Hambly
- Discipline of Pathology, Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
| | - Xiaoping Cai
- Discipline of Pathology, Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
| | - Roshanak Aran
- Discipline of Pathology, Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
| | - Genevieve Fong
- Discipline of Pathology, Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
| | - Abigail Vellajo
- Discipline of Pathology, Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
| | - Nathan J J Martin
- Discipline of Pathology, Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
| | - XiaoSuo Wang
- Discipline of Pathology, Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
| | - Joanne M Dennis
- Discipline of Pathology, Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
| | - Arpeeta Sharma
- Department of Medicine, Monash University, Melbourne, VIC, Australia
| | - Waled A Shihata
- Cardiovascular Disease Program, Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia.,Department of Pharmacology, Monash University, Melbourne, VIC, Australia.,Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Jaye P F Chin-Dusting
- Cardiovascular Disease Program, Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia.,Department of Pharmacology, Monash University, Melbourne, VIC, Australia.,Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Judy B de Haan
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Alexandra Sharland
- Transplantation Immunobiology Group, Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
| | - Carolyn L Geczy
- School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Ben Freedman
- ANZAC Research and Heart Research Institutes, Charles Perkins Centre, University of Sydney, Sydney, NSW, Australia
| | - Paul K Witting
- Discipline of Pathology, Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
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Yuan Y, Sun H, Sun Z. Advanced glycation end products (AGEs) increase renal lipid accumulation: a pathogenic factor of diabetic nephropathy (DN). Lipids Health Dis 2017; 16:126. [PMID: 28659153 PMCID: PMC5490221 DOI: 10.1186/s12944-017-0522-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 06/16/2017] [Indexed: 12/26/2022] Open
Abstract
Background Advanced glycation end products (AGEs) are pathogenic factors of diabetic nephropathy (DN), causing renal damage in various ways. The aim of this study is to investigate the ectopic lipid accumulation caused by AGEs in human renal tubular epithelial cell line (HK-2) cells and the kidney of type 2 diabetic rats. Methods In vivo study, diabetes was induced in male Sprague–Dawley rats through intraperitoneal injection of high-fat/high-sucrose diet and low-dose streptozocin (STZ). Two weeks after STZ injection, the diabetic rats were randomly divided into two groups, namely, untreated diabetic and Aminoguanidine Hydrochloride (AG, an AGEs formation inhibitor)-treated (100 mg/Kg/day, i.g., for 8 weeks) group. In vitro study, according to the different treatments, HK-2 were divided into 6 groups. Intracellular cholesterol content was assessed by Oil Red O staining and cholesterol enzymatic assay. Expression of mRNA and protein of molecules controlling cholesterol homeostasis in the treated cells was examined by real-time quantitative PCR and western blotting, respectively. SREBP cleavage-activating protein (SCAP) translocation was detected by confocal microscopy. Results Here we found Nε-(carboxymethyl) lysine (CML, a member of the AGEs family) increased Oil Red O staining and intracellular cholesterol ester (CE) in HK-2 cells; Anti-RAGE (AGEs receptor) reduced lipid droplets and the CE level. A strong staining of Oil Red O was also found in the renal tubules of the diabetic rats, which could be alleviated by AG. CML upregulated both mRNA and protein expression of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoAR), LDL receptor (LDLr), sterol regulatory element binding protein-2 (SREBP-2) and SCAP, which were inhibited by anti-RAGE. The upregulation of these molecules in the kidney of the diabetic rats was also ameliorated by AG. Furthermore, AG reduced serum and renal CML deposition, and improved urine protein and u-NGAL in type 2 diabetic rats. Conclusions Overall, these results suggest that CML caused DN might be via disturbing the intracellular feedback regulation of cholesterol. Inhibition of CML-induced lipid accumulation might be a potential renoprotective role in the progression of DN.
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Affiliation(s)
- Yang Yuan
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, No. 87 DingJiaQiao Road, Nanjing, 210009, People's Republic of China
| | - Hong Sun
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, No. 87 DingJiaQiao Road, Nanjing, 210009, People's Republic of China.,Department of Endocrinology and Metabolism, The first Affiliated Hospital of Soochow University, 188 shizi street, suzhou, 215006, jiangsu, China
| | - Zilin Sun
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, No. 87 DingJiaQiao Road, Nanjing, 210009, People's Republic of China.
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Yang P, Xiao Y, Luo X, Zhao Y, Zhao L, Wang Y, Wu T, Wei L, Chen Y. Inflammatory stress promotes the development of obesity-related chronic kidney disease via CD36 in mice. J Lipid Res 2017; 58:1417-1427. [PMID: 28536108 DOI: 10.1194/jlr.m076216] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/20/2017] [Indexed: 12/28/2022] Open
Abstract
Ectopic fat located in the kidney has emerged as a novel cause of obesity-related chronic kidney disease (CKD). In this study, we aimed to investigate whether inflammatory stress promotes ectopic lipid deposition in the kidney and causes renal injury in obese mice and whether the pathological process is mediated by the fatty acid translocase, CD36. High-fat diet (HFD) feeding alone resulted in obesity, hyperlipidemia, and slight renal lipid accumulation in mice, which nevertheless had normal kidney function. HFD-fed mice with chronic inflammation had severe renal steatosis and obvious glomerular and tubular damage, which was accompanied by increased CD36 expression. Interestingly, CD36 deficiency in HFD-fed mice eliminated renal lipid accumulation and pathological changes induced by chronic inflammation. In both human mesangial cells (HMCs) and human kidney 2 (HK2) cells, inflammatory stress increased the efficiency of CD36 protein incorporation into membrane lipid rafts, promoting FFA uptake and intracellular lipid accumulation. Silencing of CD36 in vitro markedly attenuated FFA uptake, lipid accumulation, and cellular stress induced by inflammatory stress. We conclude that inflammatory stress aggravates renal injury by activation of the CD36 pathway, suggesting that this mechanism may operate in obese individuals with chronic inflammation, making them prone to CKD.
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Affiliation(s)
- Ping Yang
- Centre for Lipid Research and Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, Second Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China
| | - Yayun Xiao
- Centre for Lipid Research and Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, Second Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China
| | - Xuan Luo
- Centre for Lipid Research and Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, Second Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China
| | - Yunfei Zhao
- School of Biological and Chemical Engineering, Chongqing University of Education, Chongqing 400067, China
| | - Lei Zhao
- Centre for Lipid Research and Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, Second Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China
| | - Yan Wang
- Centre for Lipid Research and Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, Second Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China
| | - Tingting Wu
- Centre for Lipid Research and Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, Second Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China
| | - Li Wei
- Centre for Lipid Research and Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, Second Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China
| | - Yaxi Chen
- Centre for Lipid Research and Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, Second Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China.
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Yang H, Cui J, Shi J, Yang B, Wang M, Wu D, Zhang G, Liu W, Li Q. Endoplasmic reticulum stress participates in inflammation-accelerated, lipid-mediated injury of human glomerular mesangial cells. Nephrology (Carlton) 2017; 22:234-242. [PMID: 26890338 DOI: 10.1111/nep.12748] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 02/06/2016] [Accepted: 02/11/2016] [Indexed: 11/29/2022]
Abstract
AIM The mechanism of lipid-mediated injury of human glomerular mesangial cells (HMCs) remains unclear. We investigated the association between endoplasmic reticulum (ER) stress and lipid-mediated injury in HMCs in vitro and the potential efficacy of a therapeutic approach targeting ER stress. METHODS Human glomerular mesangial cells were exposed to low-density lipoprotein (LDL) and/or interleukin-1β (IL-1β). For evaluation of whether ER stress participates in lipid-mediated injury to HMCs, HMCs were pretreated with tunicamycin or treated with sodium 4-phenylbutyrate (4-PBA). RESULTS Incubation of HMCs with LDL + IL-1β significantly increased lipid accumulation and induced phenotypic changes. ER stress was induced in lipid-loaded HMCs, as indicated by upregulation of glucose-regulated protein 78 (GRP78) and protein kinase RNA-like ER kinase (PERK) proteins. Moreover, persistent ER stress increased expression of nuclear factor (NF)-κB p65 protein, fibronectin, and α-smooth muscle actin (α-SMA) mRNA partly through the PERK - eukaryotic initiation factor-2α (eIF2α) pathway. Preconditioning with ER stress by tunicamycin and inhibition of ER stress by 4-PBA both reversed the phenotypic changes and decreased lipid accumulation and inflammatory cytokine secretion by the PERK - eIF2α pathway. CONCLUSION These data provide evidence that ER stress participates in inflammation associated with lipid-induced injury of HMCs. Modulation of ER stress may be a novel therapeutic approach for combating lipid-induced injury of HMCs.
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Affiliation(s)
- Haiping Yang
- Department of Nephroimmunology, Key Laboratory of the Ministry of Education, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Jingjing Cui
- Department of Nephroimmunology, Key Laboratory of the Ministry of Education, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Jing Shi
- Department of Nephroimmunology, Key Laboratory of the Ministry of Education, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Baohui Yang
- Department of Nephroimmunology, Key Laboratory of the Ministry of Education, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Mo Wang
- Department of Nephroimmunology, Key Laboratory of the Ministry of Education, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Daoqi Wu
- Department of Nephroimmunology, Key Laboratory of the Ministry of Education, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Gaofu Zhang
- Department of Nephroimmunology, Key Laboratory of the Ministry of Education, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Wei Liu
- Department of Nephroimmunology, Key Laboratory of the Ministry of Education, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Qiu Li
- Department of Nephroimmunology, Key Laboratory of the Ministry of Education, Children's Hospital of Chongqing Medical University, Chongqing, China
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Chen L, Tian G, Tang W, Luo W, Liu P, Ma Z. Protective effect of luteolin on streptozotocin-induced diabetic renal damage in mice via the regulation of RIP140/NF-кB pathway and insulin signalling pathway. J Funct Foods 2016. [DOI: 10.1016/j.jff.2016.01.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Zhong S, Zhao L, Li Q, Yang P, Varghese Z, Moorhead JF, Chen Y, Ruan XZ. Inflammatory Stress Exacerbated Mesangial Foam Cell Formation and Renal Injury via Disrupting Cellular Cholesterol Homeostasis. Inflammation 2016; 38:959-71. [PMID: 25387652 DOI: 10.1007/s10753-014-0058-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Inflammation and lipids play significant roles in the progression of chronic kidney disease. This study was designed to investigate whether inflammation disrupts cellular cholesterol homeostasis and causes the lipid nephrotoxicity in vitro and in vivo, and explored its underlying mechanisms. Inflammatory stress was induced by cytokines (interleukin-1β (IL-1β); tumor necrosis factor α (TNF-α)) to human mesangial cells (HMCs) in vitro and by subcutaneous casein injection in C57BL/6J mice in vivo. The data showed that inflammatory stress exacerbated renal cholesterol ester accumulation in vitro and in vivo. Inflammation increased cellular cholesterol uptake and synthesis via upregulating the expression of low-density lipoprotein receptor (LDLr) and 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCoA-R), while it decreased cholesterol efflux via downregulating the expression of liver X receptor alpha and ATP-binding cassette transporter A1. The increased lipid accumulation by inflammatory stress induced reactive oxygen species (ROS) and increased levels of endoplasmic reticulum (ER) stress markers (inositol-requiring protein 1 and activating transcription factor 6) in HMCs and kidneys of C57BL/6J mice. This study implied that inflammation promoted renal lipid accumulation and foam cell formation by disrupting cellular cholesterol homeostasis. Increased intracellular lipids under inflammatory stress caused oxidative stress and ER stress in vitro and in vivo which may contribute to renal injury and progression of chronic kidney disease.
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Affiliation(s)
- Shan Zhong
- Centre for Lipid Research, Key Laboratory of Metabolism on Lipid and Glucose, the Second Affiliated Hospital, Chongqing Medical University, Chongqing, 400016, China
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Yang S, Zhang W, Zhen Q, Gao R, Du T, Xiao X, Wang Z, Ge Q, Hu J, Ye P, Zhu Q, Li Q. Impaired adipogenesis in adipose tissue associated with hepatic lipid deposition induced by chronic inflammation in mice with chew diet. Life Sci 2015; 137:7-13. [DOI: 10.1016/j.lfs.2015.07.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 06/12/2015] [Accepted: 07/11/2015] [Indexed: 12/14/2022]
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Zheng Y, Tang L, Huang W, Yan R, Ren F, Luo L, Zhang L. Anti-Inflammatory Effects of Ang-(1-7) in Ameliorating HFD-Induced Renal Injury through LDLr-SREBP2-SCAP Pathway. PLoS One 2015; 10:e0136187. [PMID: 26291618 PMCID: PMC4546194 DOI: 10.1371/journal.pone.0136187] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 07/30/2015] [Indexed: 11/30/2022] Open
Abstract
The angiotensin converting enzyme 2-angiotensin-(1–7)-Mas axis (ACE2-Ang-(1–7)-Mas axis) is reported to participate in lipid metabolism in kidney, but its precise effects and underlying mechanisms remain unknown. We hypothesized that Ang-(1–7) reduces lipid accumulation and improves renal injury through the low density lipoprotein receptor–sterol regulatory element binding proteins 2–SREBP cleavage activating protein (LDLr-SREBP2-SCAP) system by suppressing inflammation in high fat diet (HFD)-fed mice. In this study, male C57BL/6 mice were randomized into four groups: STD (standard diet)+saline, HFD+saline, HFD+Ang-(1–7) and STD+Ang-(1–7). After 10 weeks of feeding, mice were administered Ang-(1–7) or saline for two weeks. We found that high inflammation status induced by HFD disrupted the LDLr-SREBP2-SCAP feedback system. Treatment of mice fed a high-fat diet with Ang-(1–7) induced significant improvement in inflammatory status, following the downregulation of LDLr, SREBP2 and SCAP, and then, decreased lipid deposition in kidney and improved renal injury. In conclusion, the anti-inflammatory effect of Ang-(1–7) alleviates renal injury triggered by lipid metabolic disorders through a LDLr- SREBP2-SCAP pathway.
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Affiliation(s)
- Yaning Zheng
- Department of Nephrology, Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Lin Tang
- Department of Nephrology, Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
- * E-mail:
| | - Wenhan Huang
- Department of Nephrology, Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Ruyu Yan
- Department of Nephrology, Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Feifeng Ren
- Department of Nephrology, Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Lei Luo
- Department of Nephrology, Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Ling Zhang
- Department of Nephrology, Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
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Difference in LDL receptor feedback regulation in macrophages and vascular smooth muscle cells: foam cell transformation under inflammatory stress. Inflammation 2014; 37:555-65. [PMID: 24297394 DOI: 10.1007/s10753-013-9769-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Macrophages and vascular smooth muscle cells (VSMCs) are the major cell types involved in foam cell formation associated with atherosclerosis. The aim of this experiment was to clarify cell-specific regulation of LDL receptor in THP-1 macrophages and human VSMCs under physiological and inflammatory conditions and its potential mechanisms. Inflammatory stress was induced by adding lipopolysaccharide (LPS) to human THP-1 macrophages and human VSMCs. Intracellular total cholesterol, free cholesterol, and cholesterol ester were measured by an enzymic assay. Oil Red O staining was used to visualize lipid droplet accumulation in cells. Total cellular RNA was isolated from cells for detecting LDL receptor, sterol regulatory element binding protein (SREBP)-2 and SREBP cleavage-activating protein (SCAP) mRNA levels using real-time quantitative polymerase chain reaction. LDL receptor, SREBP-2 and SCAP protein expression were examined by Western blotting. The translocation of SCAP from ER to Golgi was detected by confocal microscopy. LDL loading increased intracellular cholesterol level, reducing LDL receptor mRNA level in both THP-1 macrophages and VSMCs under physiological conditions. The IC50 in VSMCs was 11.25 μg/ml, which is much lower than 18.125 μg/ml in THP-1 macrophages. With the increase in concentration of LPS (0-400 ng/ml), the LDL receptor mRNA levels were upregulated in both cells, but the curve of LDL receptor mRNA in VSMCs exhibited a flatter profile than that of THP-1 macrophages. Under the treatment of 200 ng/ml of LPS, the upregulation fold of the LDL receptor mRNA in THP-1 macrophages was much higher than that of VSMCs (0.33 vs 0.04). LDL receptor blocking agent heparin decreased lipid droplets induced by LPS significantly in THP-1 macrophages and VSMCs. LDL loading reduced the SREBP2 and SCAP protein expression under physiological conditions. Exposure to LPS caused overexpression of SREBP2 and SCAP despite a high concentration of LDL in the culture medium, and increased translocation of SCAP from the ER to the Golgi in the presence of 25 μg/ml of LDL. Inflammatory stress disrupts LDL receptor negative feedback regulation induced by intracellular cholesterol in both cell types, to a greater degree in THP-1 macrophages, which could be one reason why THP-1 macrophages are more prone to become foam cells under inflammatory stress.
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Roles of chronic low-grade inflammation in the development of ectopic fat deposition. Mediators Inflamm 2014; 2014:418185. [PMID: 25143667 PMCID: PMC4131072 DOI: 10.1155/2014/418185] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Revised: 05/13/2014] [Accepted: 05/16/2014] [Indexed: 12/12/2022] Open
Abstract
Pattern of fat distribution is a major determinant for metabolic homeostasis. As a depot of energy, the storage of triglycerides in adipose tissue contributes to the normal fat distribution. Decreased capacity of fat storage in adipose tissue may result in ectopic fat deposition in nonadipose tissues such as liver, pancreas, and kidney. As a critical biomarker of metabolic complications, chronic low-grade inflammation may have the ability to affect the process of lipid accumulation and further lead to the disorder of fat distribution. In this review, we have collected the evidence linking inflammation with ectopic fat deposition to get a better understanding of the underlying mechanism, which may provide us with novel therapeutic strategies for metabolic disorders.
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Chen Y, Zhao L, Li Q, Wheeler DC, Varghese Z, Moorhead JF, Powis SH, Ruan XZ. Inflammatory stress reduces the effectiveness of statins in the kidney by disrupting HMGCoA reductase feedback regulation. Nephrol Dial Transplant 2014; 29:1864-78. [PMID: 24895437 DOI: 10.1093/ndt/gfu203] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Patients with chronic kidney disease (CKD) are unlikely to gain the same benefit from conventional doses of statins as do patients with cardiovascular disease alone. This study investigated whether inflammation accompanying CKD causes statin resistance. METHODS Inflammatory stress was induced by adding cytokines and lipopolysaccharide (LPS) to human mesangial cells (HMCs) in vitro, and in vivo by subcutaneous casein injection in apolipoprotein E, scavenger receptors class A and CD36 triple knockout mice. RESULTS Inflammatory stress exacerbated cholesterol accumulation and was accompanied in vitro and in vivo by increased HMGCoA reductase (HMGCoA-R) mRNA and protein expression mediated via activation of the sterol regulatory element-binding protein cleavage-activating protein (SCAP)/sterol regulatory element-binding protein 2 pathway. Atorvastatin reduced HMGCoA-R enzymatic activity and intracellular cholesterol synthesis in vitro; however, inflammatory stress weakened these suppressive effects. Atorvastatin at concentrations of 15 µM inhibited HMGCoA-R activity by 50% (IC50) in HMCs, but the same concentration in the presence of interleukin (IL)-1β resulted in only 30% inhibition of HMGCoA-R activity in HMCs. Knocking down SCAP prevented statin resistance induced by IL-1β, and overexpression of SCAP-induced statin resistance even without inflammatory stress. In vivo, the amount of atorvastatin required to lower serum cholesterol and decrease kidney lipid accumulation rose from 2 to 10 mg/kg/day in the presence of inflammatory stress. CONCLUSIONS Inflammatory stress can disrupt HMGCoA-R-mediated cholesterol synthesis resulting in intracellular lipid accumulation and statin resistance.
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Affiliation(s)
- Yaxi Chen
- Centre for Lipid Research, Key Laboratory of Metabolism on Lipid and Glucose, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Lei Zhao
- Centre for Lipid Research, Key Laboratory of Metabolism on Lipid and Glucose, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Qing Li
- Centre for Lipid Research, Key Laboratory of Metabolism on Lipid and Glucose, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - David C Wheeler
- John Moorhead Research Laboratory, Centre for Nephrology, University College London (UCL) Medical School, Royal Free Campus, University College London, London, UK
| | - Zac Varghese
- John Moorhead Research Laboratory, Centre for Nephrology, University College London (UCL) Medical School, Royal Free Campus, University College London, London, UK
| | - John F Moorhead
- John Moorhead Research Laboratory, Centre for Nephrology, University College London (UCL) Medical School, Royal Free Campus, University College London, London, UK
| | - Stephen H Powis
- John Moorhead Research Laboratory, Centre for Nephrology, University College London (UCL) Medical School, Royal Free Campus, University College London, London, UK
| | - Xiong Z Ruan
- Centre for Lipid Research, Key Laboratory of Metabolism on Lipid and Glucose, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
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16
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Betaine supplementation protects against high-fructose-induced renal injury in rats. J Nutr Biochem 2014; 25:353-62. [DOI: 10.1016/j.jnutbio.2013.11.010] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 11/18/2013] [Accepted: 11/18/2013] [Indexed: 01/26/2023]
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17
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Patel M, Wang XX, Magomedova L, John R, Rasheed A, Santamaria H, Wang W, Tsai R, Qiu L, Orellana A, Advani A, Levi M, Cummins CL. Liver X receptors preserve renal glomerular integrity under normoglycaemia and in diabetes in mice. Diabetologia 2014; 57:435-46. [PMID: 24201575 DOI: 10.1007/s00125-013-3095-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 10/01/2013] [Indexed: 10/26/2022]
Abstract
AIMS/HYPOTHESIS Liver X receptors (LXRs) α and β are nuclear hormone receptors that are widely expressed in the kidney. They promote cholesterol efflux from cells and inhibit inflammatory responses by regulating gene transcription. Here, we hypothesised (1) that LXR deficiency would promote renal decline in a mouse model of diabetes by accelerating intraglomerular cholesterol accumulation and, conversely, (2) that LXR agonism would attenuate renal decline in diabetes. METHODS Diabetes was induced with streptozotocin (STZ) and maintained for 14 weeks in Lxrα/β (+/+) (Lxrα, also known as Nr1h3; Lxrβ, also known as Nr1h2) and Lxrα/β (-/-) mice. In addition, STZ-injected DBA/2J mice were treated with vehicle or the LXR agonist N,N-dimethyl-hydroxycholenamide (DMHCA) (80 mg/kg daily) for 10 weeks. To determine the role of cholesterol in diabetic nephropathy (DN), mice were placed on a Western diet after hyperglycaemia developed. RESULTS Even in the absence of diabetes, Lxrα/β (-/-) mice exhibited a tenfold increase in the albumin:creatinine ratio and a 40-fold increase in glomerular lipid accumulation compared with Lxrα/β (+/+) mice. When challenged with diabetes, Lxrα/β (-/-) mice showed accelerated mesangial matrix expansion and glomerular lipid accumulation, with upregulation of inflammatory and oxidative stress markers. In the DN-sensitive STZ DBA/2J mouse model, DMHCA treatment significantly decreased albumin and nephrin excretion (by 50% each), glomerular lipids and plasma triacylglycerol (by 70%) and cholesterol (by 48%); it also decreased kidney inflammatory and oxidative stress markers compared with vehicle-treated mice. CONCLUSIONS/INTERPRETATION These data support the idea that LXR plays an important role in the normal and diabetic kidney, while showing that LXR, through its inhibitory effect on inflammation and cholesterol accumulation in glomeruli, could also be a novel therapeutic target for DN.
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Affiliation(s)
- Monika Patel
- Faculty of Pharmacy, University of Toronto, 144 College St, Toronto, ON, M5S 3M2, Canada
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18
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Ma KL, Zhang Y, Liu J, Wu Y, Hu ZB, Ruan XZ, Liu BC. Establishment of an inflamed animal model of diabetic nephropathy. Int J Biol Sci 2014; 10:149-59. [PMID: 24520213 PMCID: PMC3920170 DOI: 10.7150/ijbs.7875] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2013] [Accepted: 01/06/2014] [Indexed: 01/08/2023] Open
Abstract
Aims Inflammatory stress plays a crucial role in the progression of diabetic nephropathy (DN). This study aimed to establish a novel inflamed animal model of DN and to evaluate its significance in DN. Methods Nondiabetic db/m mice and diabetic db/db mice were randomly divided into four groups: db/m, db/m+casein, db/db, and db/db+casein for eight weeks. Casein was subcutaneously injected to induce chronic inflammation. Body weight and albumin to creatinine ratio (ACR) in the urine were measured every week. The plasma levels of serum amyloid protein A (SAA) and tumour necrotic factor-α (TNF-α) were determined with the enzyme-linked immunosorbent assay. The morphological changes to the renal pathology and ultra-microstructures were checked by pathological staining and electron microscopy. Immunofluorescent staining and Western blotting were used to determine the protein expression of podocyte-specific molecules and inflammatory cytokines in kidneys. Results ACR, plasma levels of SAA and TNF-α, protein expression of inflammatory cytokines, mesangial expansion, collagen accumulation, and foot process effacement in kidneys of casein-injected db/db mice were significantly increased compared with the db/db mice. Casein injection markedly decreased the protein expression of Wilms' tumor-1 and nephrin in kidneys of db/db mice, which are specific podocyte biomarkers, suggesting that chronic inflammation accelerates podocyte injuries in db/db mice. Interestingly, no obvious urinary protein, inflammatory cytokine expression, or histological changes in the kidneys of casein-injected db/m mice were found compared with the db/m mice. Conclusion An inflamed animal model of DN was successfully established and may provide a useful tool for investigating the pathogenesis of DN under inflammatory stress.
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Affiliation(s)
- Kun Ling Ma
- 1. Institute of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing City, Jiangsu Province, China
| | - Yang Zhang
- 1. Institute of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing City, Jiangsu Province, China
| | - Jing Liu
- 1. Institute of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing City, Jiangsu Province, China
| | - Yu Wu
- 1. Institute of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing City, Jiangsu Province, China
| | - Ze Bo Hu
- 1. Institute of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing City, Jiangsu Province, China
| | - Xiong Zhong Ruan
- 2. Centre for Nephrology, University College London (UCL) Medical School, Royal Free Campus, UK
| | - Bi Cheng Liu
- 1. Institute of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing City, Jiangsu Province, China
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Chen Y, Ku H, Zhao L, Wheeler DC, Li LC, Li Q, Varghese Z, Moorhead JF, Powis SH, Huang A, Ruan XZ. Inflammatory stress induces statin resistance by disrupting 3-hydroxy-3-methylglutaryl-CoA reductase feedback regulation. Arterioscler Thromb Vasc Biol 2013; 34:365-76. [PMID: 24233489 DOI: 10.1161/atvbaha.113.301301] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE The risk of cardiovascular disease is increased by up to 33 to 50× in chronic inflammatory states and convention doses of statins may not provide the same cardiovascular protection as in noninflamed patients. This study investigated whether the increase in 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCoA-R)-mediated cholesterol synthesis observed under inflammatory stress was resistant to the action of statins and if so, whether this was because of interference with the sterol regulatory element binding protein cleavage-activating protein pathway. APPROACH AND RESULTS Inflammatory stress was induced by adding cytokines (interleukin-1β, tumor necrosis factor-α, and interleukin-6) and lipopolysaccharides to vascular smooth muscle cells in vitro and by subcutaneous casein injection in apolipoprotein E/scavenger receptors class A/CD36 triple knockout mice in vivo. Inflammatory stress exacerbated cholesterol ester accumulation and was accompanied in vitro and in vivo by increased HMGCoA-R mRNA and protein expression mediated via activation of the sterol regulatory element binding protein cleavage-activating protein/sterol regulatory element binding protein-2 pathway. Atorvastatin reduced HMGCoA-R enzymatic activity and intracellular cholesterol synthesis in vitro. However, inflammatory stress weakened these suppressive effects. Atorvastatin at concentrations of 16 μmol/L inhibited HMGCoA-R activity by 50% in vascular smooth muscle cells, but the same concentration resulted in only 30% of HMGCoA-R activity in vascular smooth muscle cells in the presence of interleukin-1β. Knocking down sterol regulatory element binding protein cleavage-activating protein prevented statin resistance induced by interleukin-1β, and overexpression of sterol regulatory element binding protein cleavage-activating protein induced statin resistance even without inflammatory stress. In vivo, the amount of atorvastatin required to lower serum cholesterol and decrease aortic lipid accumulation rose from 2 to 10 mg/kg per day in the presence of inflammatory stress. CONCLUSIONS Increased cholesterol synthesis mediated by HMGCoA-R under inflammatory stress may be one of the mechanisms for intracellular lipid accumulation and statin resistance.
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Affiliation(s)
- Yaxi Chen
- From the Key Laboratory of Metabolism on Lipid and Glucose, Centre for Lipid Research, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China (Y.C., L.Z., Q.L., A.H., X.Z.R.); Division of Nephrology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan (L.C.L.); and John Moorhead Research Laboratory, Centre for Nephrology, University College London (UCL) Medical School, United Kingdom (H.K., D.C.W., Z.V., J.F.M., S.H.P., X.Z.R.)
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Zhou TB. Signaling pathways of apoE and its role of gene expression in glomerulus diseases. J Recept Signal Transduct Res 2013; 33:73-8. [PMID: 23384034 DOI: 10.3109/10799893.2013.765466] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The roles of apolipoprotein E (apoE) in regulating plasma lipids and lipoproteins levels have been investigated for over several decades. However, in different tissues/cells, the role of apoE was different, such as that it was a risk factor for cancer, but some reports stated that apoE was a protective factor for renal diseases. At the moment, most of the studies find that apoE not only acts as a ligand for metabolism of lipids, but also plays as a factor to regulate lots of signaling pathways. There was rare review to sum up the signaling pathways for apoE, and there was also rare review to widely review the gene expression of apoE in glomerulus diseases. This review was performed to provide a relatively complete signaling pathways flowchart for apoE to the investigators who were interested in the roles of apoE in the pathogenesis of glomerulus diseases. In the past decades, some studies were also performed to explore the association of apoE gene expression with the risk of glomerulus diseases. However, the role of apoE in the pathogenesis of glomerulus diseases was controversial. Here, the signal transduction pathways of apoE and its role of gene expression in the pathogenesis of glomerulus diseases were reviewed.
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Affiliation(s)
- Tian-Biao Zhou
- Department of Pediatric Nephrology, The First Affiliated Hospital of Guangxi Medical University, Guangxi, China.
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Li LC, Varghese Z, Moorhead JF, Lee CT, Chen JB, Ruan XZ. Cross-talk between TLR4-MyD88-NF-κB and SCAP-SREBP2 pathways mediates macrophage foam cell formation. Am J Physiol Heart Circ Physiol 2013; 304:H874-84. [PMID: 23335792 DOI: 10.1152/ajpheart.00096.2012] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Myeloid differentiation factor 88 (MyD88) and NF-κB play central roles in mediating signal transduction of the Toll-like receptor (TLR) superfamily in human macrophages. The feedback regulation of LDL receptor (LDLR) and 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoAR) are mediated by the sterol regulatory element-binding protein (SREBP) cleavage-activating protein (SCAP)-SREBP2 pathway and are key regulatory elements for cholesterol homeostasis in human cells. This study was designed to investigate cross-talk between TLR4-MyD88-NF-κB and SCAP-SREBP2 pathways in macrophage foam cell formation. phorbol 12-myristate 13-acetate-activated THP-1 macrophages were transfected with negative control or MyD88 small interfering (si)RNA. Transfected cells were incubated with LPS in the absence or presence of LDL or IκB kinase (IKK) inhibitor (BMS-345541). Intracellular cholesterol content was assessed. mRNA and protein expression of LDLR, HMG-CoAR, SCAP, and SREBP2 were examined by real-time RT-PCR and Western blot analysis. Intracellular translocation of SCAP in the organelles was detected by immunofluorecence and confocal microscopy. We demonstrated that LPS-induced cholesterol accumulation was attenuated by applying siRNA against MyD88 in the absence or presence of LDL. LPS increased both gene and protein expression of LDLR and HMG-CoAR by increasing expression and abnormal translocation of SCAP from the endoplasmic reticulum to the Golgi. These effects were blocked by knockdown of MyD88 or blockade of IKK or by knockdown of SCAP, suggesting that the cross-talk between NF-κB and SCAP plays an important role in macrophage foam cell formation and that interfering with the cross-talk might be a potential approach in preventing LPS-induced macrophage foam cell formation.
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Affiliation(s)
- Lung-Chih Li
- John Moorhead Renal Research Laboratory, Centre for Nephrology, University College London Medical School, Royal Free Campus, London, United Kingdom
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Sun H, Yuan Y, Sun ZL. Cholesterol Contributes to Diabetic Nephropathy through SCAP-SREBP-2 Pathway. Int J Endocrinol 2013; 2013:592576. [PMID: 24369464 PMCID: PMC3863482 DOI: 10.1155/2013/592576] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2013] [Revised: 10/15/2013] [Accepted: 10/15/2013] [Indexed: 12/31/2022] Open
Abstract
Diabetic nephropathy (DN) has been associated with the presence of lipid deposition. We hypothesized that the disruption of intracellular cholesterol feedback may contribute to DN. Diabetes was induced by high fat/sucrose diet and low-dose intraperitoneal injection of streptozocin (STZ) in male Sprague-Dawley rats. Then diabetic rats were randomly divided into two groups: untreated diabetic group (DM) and atorvastatin-treated group (DM + AT). We found that the levels of serum blood urea nitrogen and creatinine, as well as 24-hour urine protein and urinary neutrophil gelatinase-associated lipocalin, were significantly increased in diabetic rats. This result indicated that the diabetic rats suffered from functional renal damage. We also observed lipid droplet accumulation and increase in 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoAR), low density lipoprotein receptor (LDLr), sterol regulatory element binding protein-2 (SREBP-2), and SREBP-cleavage activating protein (SCAP) in the kidneys of diabetic rats. However, atorvastatin ameliorated renal lipid accumulation and improved the renal function of diabetic rats despite an increase in mRNA and protein expressions of HMG-CoAR, LDLr, and SREBP-2. These results demonstrated that intracellular cholesterol feedback regulation is disrupted in rats with type 2 diabetes, thereby causing renal cholesterol accumulation. Atorvastatin ameliorated renal cholesterol accumulation by reducing renal cholesterol synthesis.
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Affiliation(s)
- Hong Sun
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, Medical School, Southeast University, Nanjing 210009, China
| | - Yang Yuan
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, Medical School, Southeast University, Nanjing 210009, China
- *Yang Yuan:
| | - Zi-Lin Sun
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, Medical School, Southeast University, Nanjing 210009, China
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Ma KL, Liu J, Ni J, Zhang Y, Lv LL, Tang RN, Ni HF, Ruan XZ, Liu BC. Inflammatory stress exacerbates the progression of cardiac fibrosis in high-fat-fed apolipoprotein E knockout mice via endothelial-mesenchymal transition. Int J Med Sci 2013; 10:420-6. [PMID: 23471419 PMCID: PMC3590602 DOI: 10.7150/ijms.5723] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 02/25/2013] [Indexed: 02/06/2023] Open
Abstract
Background Chronic inflammation plays a crucial role in the progression of cardiac fibrosis. This study investigated whether inflammation exacerbated the progression of cardiac fibrosis in high-fat-fed apolipoprotein E knockout (ApoE KO) mice via endothelial-mesenchymal transition (EndMT). Methods Twenty-four male ApoE KO mice were divided into normal chow diet (Control), high-fat diet (HFD), or high-fat diet plus 10% casein injection (inflamed) groups for 8 weeks. The body weight of ApoE KO mice was measured at each week. The lipid profile and serum amyloid A (SAA) levels were examined using clinical biochemistry and enzyme-linked immunosorbent assays, respectively. Cardiac lipid and collagen accumulation was visualised with haematoxylin-eosin (HE) and Masson's trichrome staining. EndMT-related molecule expression was examined by immunohistochemistry and Western blotting. Results SAA levels were increased in the inflamed group compared with the HFD and control groups, suggesting that inflammation was successfully induced. There were no differences in body weight among three groups at each week. Interestingly, inflammation significantly reduced serum total cholesterol, triglyceride, and low-density lipoprotein (LDL) levels compared with the HFD mice. However, both foam cell formation in cardiac blood vessels and cardiac collagen deposition were increased in the inflamed group, as demonstrated by HE and Masson trichrome staining. Furthermore, inflammation reduced protein expression of CD31 and increased protein expression of alpha-smooth muscle actin (α-SMA) and collagen I, which contribute to cardiac EndMT. Conclusions Inflammatory stress exacerbates the progression of cardiac fibrosis in high-fat-fed ApoE KO mice via EndMT, suggesting that hyperlipidaemia and inflammation act synergistically to redistribute plasma lipids to cardiac tissues and accelerate the progression of cardiac fibrosis.
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Affiliation(s)
- Kun Ling Ma
- Institute of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing City, Jiangsu Province, China
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