1
|
Zhong W, Fan B, Cong H, Wang T, Gu J. Oleic acid-induced perilipin 5 expression and lipid droplets formation are regulated by the PI3K/PPARα pathway in HepG2 cells. Appl Physiol Nutr Metab 2019; 44:840-848. [PMID: 31274012 DOI: 10.1139/apnm-2018-0729] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Perilipin 5 (Plin5), a member of the PAT (Perilipin, ADRP, and Tip47) protein family, has been implicated in the regulation of cellular neutral lipid accumulation in nonalcoholic fatty liver diseases. However, the underlying regulatory mechanisms of Plin5 are not clear. The goal of the present study was to explore the mechanism of oleic acid (OA)-induced Plin5 expression in HepG2 cells. We found that the expression of Plin5 was increased during OA-induced lipid droplets formation in a dose- and time-dependent manner. During this process of OA-stimulated lipid droplets formation, peroxisome proliferator-activated receptor alpha (PPARα) was also upregulated. When PPARα activation was blocked by GW6471, OA-induced Plin5 expression and lipid droplets formation were effectively ablated. We further found that the phosphoinositide 3-kinase (PI3K) inhibitor LY294002 was able to downregulate both PPARα and Plin5 expression and lipid droplets formation. Thus, we concluded that PI3K may, at least in part, act upstream of PPARα to regulate Plin5 expression and lipid droplets formation in HepG2 cells.
Collapse
Affiliation(s)
- Wenxia Zhong
- a Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Affiliated Hospital of China Medical University, Shenyang 110001, PR China
| | - Bin Fan
- b Department of Neurology, Shenjing Hospital, China Medical University, Shenyang 110022, PR China
| | - Huiying Cong
- a Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Affiliated Hospital of China Medical University, Shenyang 110001, PR China
| | - Tianyu Wang
- a Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Affiliated Hospital of China Medical University, Shenyang 110001, PR China
| | - Jianqiu Gu
- a Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Affiliated Hospital of China Medical University, Shenyang 110001, PR China
| |
Collapse
|
2
|
Verlaet A, van der Bolt N, Meijer B, Breynaert A, Naessens T, Konstanti P, Smidt H, Hermans N, Savelkoul HFJ, Teodorowicz M. Toll-Like Receptor-Dependent Immunomodulatory Activity of Pycnogenol ®. Nutrients 2019; 11:E214. [PMID: 30678156 PMCID: PMC6412808 DOI: 10.3390/nu11020214] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 01/07/2019] [Accepted: 01/10/2019] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Pycnogenol® (PYC), an extract of French maritime pine bark, is widely used as a dietary supplement. PYC has been shown to exert anti-inflammatory actions via inhibiting the Toll-like receptor 4 (TLR4) pathway. However, the role of the other receptors from the TLR family in the immunomodulatory activity of PYC has not been described so far. AIM The aim of this study was to investigate whether PYC might exert its immunomodulatory properties through cell membrane TLRs (TLR1/2, TLR5, and TLR2/6) other than TLR4. Moreover, the effect of gastrointestinal metabolism on the immunomodulatory effects of PYC was investigated. FINDINGS We showed that intact non-metabolized PYC dose-dependently acts as an agonist of TLR1/2 and TLR2/6 and as a partial agonist of TLR5. PYC on its own does not agonize or antagonize TLR4. However, after the formation of complexes with lipopolysaccharides (LPS), it is a potent activator of TLR4 signaling. Gastrointestinal metabolism of PYC revealed the immunosuppressive potential of the retentate fraction against TLR1/2 and TLR2/6 when compared to the control fraction containing microbiota and enzymes only. The dialyzed fraction containing PYC metabolites revealed the capacity to induce anti-inflammatory IL-10 secretion. Finally, microbially metabolized PYC affected the colonic microbiota composition during in vitro gastrointestinal digestion. CONCLUSIONS This study showed that gastrointestinal metabolism of PYC reveals its biological activity as a potential inhibitor of TLRs signaling. The results suggest that metabolized PYC acts as a partial agonist of TLR1/2 and TLR2/6 in the presence of the microbiota-derived TLR agonists (retentate fraction) and that it possesses anti-inflammatory potential reflected by the induction of IL-10 from THP-1 macrophages (dialysate fraction).
Collapse
Affiliation(s)
- Annelies Verlaet
- Department of Pharmaceutical Sciences, Laboratory of Nutrition and Functional Food Science, University of Antwerp, 2610 Wilrijk, Belgium.
| | - Nieke van der Bolt
- Department of Cell Biology and Immunology, Wageningen University & Research, 6708 WD Wageningen, The Netherlands.
| | - Ben Meijer
- Department of Cell Biology and Immunology, Wageningen University & Research, 6708 WD Wageningen, The Netherlands.
| | - Annelies Breynaert
- Department of Pharmaceutical Sciences, Laboratory of Nutrition and Functional Food Science, University of Antwerp, 2610 Wilrijk, Belgium.
| | - Tania Naessens
- Department of Pharmaceutical Sciences, Laboratory of Nutrition and Functional Food Science, University of Antwerp, 2610 Wilrijk, Belgium.
| | - Prokopis Konstanti
- Laboratory of Microbiology, Wageningen University& Research, 6708 WE Wageningen, The Netherlands.
| | - Hauke Smidt
- Laboratory of Microbiology, Wageningen University& Research, 6708 WE Wageningen, The Netherlands.
| | - Nina Hermans
- Department of Pharmaceutical Sciences, Laboratory of Nutrition and Functional Food Science, University of Antwerp, 2610 Wilrijk, Belgium.
| | - Huub F J Savelkoul
- Department of Cell Biology and Immunology, Wageningen University & Research, 6708 WD Wageningen, The Netherlands.
| | - Malgorzata Teodorowicz
- Department of Cell Biology and Immunology, Wageningen University & Research, 6708 WD Wageningen, The Netherlands.
| |
Collapse
|
3
|
Wang D, Cong H, Wang X, Cao Y, Ikuyama S, Fan B, Gu J. Pycnogenol protects against diet-induced hepatic steatosis in apolipoprotein-E-deficient mice. Am J Physiol Endocrinol Metab 2018; 315:E218-E228. [PMID: 29462565 DOI: 10.1152/ajpendo.00009.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
PycnogenolR (PYC), a combination of active flavonoids derived from French maritime pine bark, is a natural antioxidant that has various pharmacological activities. Here, we investigated the beneficial effect of PYC on diet-induced hepatic steatosis. Apolipoprotein E (ApoE)-deficient male mice were administered PYC at oral doses of 30 or 100 mg·kg-1·day-1 for 2 wk in advance and were then fed a high-cholesterol and -fat diet (HCD) for 8 wk. Biochemical, immunohistochemical, and gene expression analyses were conducted to explore the effect of PYC on lipid metabolism in ApoE-deficient mice on a HCD. Short-term treatment with HCD in ApoE-deficient mice induced hepatic injuries, such as lipid metabolism disorder and hepatic histopathological changes. We found that PYC reduced body weight and the increase of serum lipids that had been caused by HCD. Supplementation of PYC significantly reduced lipid deposition in the liver, as shown by the lowered hepatic lipid content and histopathological lesions. We subsequently detected genes related to lipid metabolism and inflammatory cytokines. The study showed that PYC markedly suppressed the expression of genes related to hepatic lipogenesis, fatty acid uptake, and lipid storage while increasing the lipolytic gene, which thus reduced hepatic lipid content. Furthermore, PYC mainly reduced the expression of inflammatory cytokines and the infiltration of inflammatory cells, which were resistant to the development of hepatic steatosis. These results demonstrate that PYC protects against the occurrence and development of hepatic steatosis and may provide a new prophylactic approach for nonalcoholic fatty liver disease (NAFLD).
Collapse
Affiliation(s)
- Difei Wang
- Department of Geriatric Endocrinology, The First Hospital of China Medical University , Shenyang , China
| | - Huiying Cong
- Department of Endocrinology and Metabolism, The Endocrine Institute and The Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Hospital of China Medical University , Shenyang , China
| | - Xiaoli Wang
- Department of Endocrinology and Metabolism, The Endocrine Institute and The Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Hospital of China Medical University , Shenyang , China
| | - Yanli Cao
- Department of Endocrinology and Metabolism, The Endocrine Institute and The Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Hospital of China Medical University , Shenyang , China
| | - Shoichiro Ikuyama
- Department of Clinical Investigation, Department of Diabetes, Endocrine and Rheumatic Diseases Oita San-ai Medical Center, Ichi, Oita , Japan
| | - Bin Fan
- Department of Neurology, Shengjing Hospital, China Medical University , Shenyang , China
| | - Jianqiu Gu
- Department of Endocrinology and Metabolism, The Endocrine Institute and The Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Hospital of China Medical University , Shenyang , China
| |
Collapse
|
4
|
Tan Y, Zhang H, Guo D, Wang J, Yuan X, Yuan Z. Adipophilin Involved in Lipopolysaccharide-Induced Inflammation in RAW264.7 Cell via Extracellular Signal-Regulated Kinase 1/2-Peroxisome Proliferator-Activated Receptor Gamma Pathway. DNA Cell Biol 2017; 36:1159-1167. [DOI: 10.1089/dna.2017.3706] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Affiliation(s)
- Yanmei Tan
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Medical School, University of South China, Hengyang, China
- Department of Pathology, Changde Vocational Technical College, Changde, China
| | - Hai Zhang
- Department of Pathology, The First Affiliated Hospital of University of South China, Hengyang, China
| | - Dongming Guo
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Medical School, University of South China, Hengyang, China
| | - Jiangbo Wang
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Medical School, University of South China, Hengyang, China
| | - Xu Yuan
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Medical School, University of South China, Hengyang, China
| | - Zhonghua Yuan
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Medical School, University of South China, Hengyang, China
| |
Collapse
|
5
|
Pycnogenol Reduces Toll-Like Receptor 4 Signaling Pathway-Mediated Atherosclerosis Formation in Apolipoprotein E-Deficient Mice. J Cardiovasc Pharmacol 2017; 68:292-303. [PMID: 27322603 DOI: 10.1097/fjc.0000000000000415] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Pycnogenol (PYC) is an extract from French maritime pine bark. Its antioxidative and anti-inflammatory effects have been shown to be beneficial for atherosclerosis. Here, we tested whether PYC could suppress high cholesterol and fat diet (HCD)-induced atherosclerosis formation in apolipoprotein E (apoE)-deficient mice. In our study, PYC suppressed oxidized low-density lipoprotein (ox-LDL)-induced lipid accumulation in peritoneal macrophages. Apolipoprotein E-deficient mice were orally administered PYC or a control solvent for ten weeks, and these mice were fed a standard diet or high cholesterol and fat diet during the latter eight weeks. Pycnogenol markedly decreased the size of atherosclerotic lesions induced by high cholesterol and fat diet compared with the nontreated controls. In addition, TLR4 expression in aortic sinus was stimulated by high cholesterol and fat diet feeding and was significantly reduced by PYC. A mechanistic analysis indicated that lipopolysaccharide (LPS) significantly increased expression of fatty acid binding protein (aP2) and macrophage scavenger receptor class A (SR-A), which were blocked by a JNK inhibitor. Furthermore, PYC inhibited the lipopolysaccharide-induced upregulation of aP2 and scavenger receptor class A via the JNK pathway. In conclusion, PYC administration effectively attenuates atherosclerosis through the TLR4-JNK pathway. Our results suggest that PYC could be a potential prophylaxis or treatment for atherosclerosis in humans.
Collapse
|
6
|
The Role of Lipid Bodies in the Microglial Aging Process and Related Diseases. Neurochem Res 2017; 42:3140-3148. [PMID: 28699057 DOI: 10.1007/s11064-017-2351-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 02/22/2017] [Accepted: 07/07/2017] [Indexed: 01/08/2023]
Abstract
Lipid bodies (LBs) have long been considered to be organelles merely for the storage of neutral lipids. However, recent studies have shown the significance of LBs in signal transduction, especially in glial cells, including microglia. Microglial cells are the resident mononuclear phagocytes in the central nervous system and have a close relationship with the aging process and neurodegenerative diseases. Evidence suggests that LBs accumulate and are remodeled during the aging process and the development of neuroinflammatory conditions. However, the mechanisms underlying the formation of LBs under these conditions and the mechanism by which LB remodeling influences the progression of neurodegeneration remain to be clarified. In this review, we have summarized the findings from recent studies with the aim of further elucidating these issues.
Collapse
|
7
|
Scheff SW, Roberts KN. Cognitive assessment of pycnogenol therapy following traumatic brain injury. Neurosci Lett 2016; 634:126-131. [PMID: 27737807 DOI: 10.1016/j.neulet.2016.10.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 09/22/2016] [Accepted: 10/08/2016] [Indexed: 12/16/2022]
Abstract
We have previously shown that pycnogenol (PYC) increases antioxidants, decreases oxidative stress, suppresses neuroinflammation and enhances synaptic plasticity following traumatic brain injury (TBI). Here, we investigate the effects of PYC on cognitive function following a controlled cortical impact (CCI). Adult Sprague-Dawley rats received a CCI injury followed by an intraperitoneal injection of PYC (50 or 100mg/kg). Seven days post trauma, subjects were evaluated in a Morris water maze (MWM) and evaluated for changes in lesion volume. Some animals were evaluated at 48h for hippocampal Fluoro-jade B (FJB) staining. The highest dose of PYC therapy significantly reduced lesion volume, with no improvement in MWM compared to vehicle controls. PYC failed to reduce the total number of FJB positive neurons in the hippocampus. These results suggest that the reduction of oxidative stress and neuroinflammation are not the key components of the secondary injury that contribute to cognitive deficits following TBI.
Collapse
Affiliation(s)
- Stephen W Scheff
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536, United States.
| | - Kelly N Roberts
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536, United States
| |
Collapse
|
8
|
Luo H, Wang J, Qiao C, Ma N, Liu D, Zhang W. Pycnogenol attenuates atherosclerosis by regulating lipid metabolism through the TLR4-NF-κB pathway. Exp Mol Med 2015; 47:e191. [PMID: 26492950 PMCID: PMC4673476 DOI: 10.1038/emm.2015.74] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 06/10/2015] [Accepted: 06/16/2015] [Indexed: 12/30/2022] Open
Abstract
Atherosclerosis is a leading cause of death worldwide and is characterized by lipid-laden foam cell formation. Recently, pycnogenol (PYC) has drawn much attention because of its prominent effect on cardiovascular disease (CVD). However, its protective effect against atherosclerosis and the underlying mechanism remains undefined. Here PYC treatment reduced areas of plaque and lipid deposition in atherosclerotic mice, concomitant with decreases in total cholesterol and triglyceride levels and increases in HDL cholesterol levels, indicating a potential antiatherosclerotic effect of PYC through the regulation of lipid levels. Additionally, PYC preconditioning markedly decreased foam cell formation and lipid accumulation in lipopolysaccharide (LPS)-stimulated human THP-1 monocytes. A mechanistic analysis indicated that PYC decreased the lipid-related protein expression of adipose differentiation-related protein (ADRP) and adipocyte lipid-binding protein (ALBP/aP2) in a dose-dependent manner. Further analysis confirmed that PYC attenuated LPS-induced lipid droplet formation via ADRP and ALBP expression through the Toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB) pathway, because pretreatment with anti-TLR4 antibody or a specific inhibitor of NF-κB (PDTC) strikingly mitigated the LPS-induced increase in ADRP and ALBP. Together, our results provide insight into the ability of PYC to attenuate bacterial infection-triggered pathological processes associated with atherosclerosis. Thus PYC may be a potential lead compound for the future development of antiatherosclerotic CVD therapy.
Collapse
Affiliation(s)
- Hong Luo
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Zhengzhou University, Henan, China
| | - Jing Wang
- Department of Stomatology, The First Affiliated Hospital of Zhengzhou University, Henan, China
| | - Chenhui Qiao
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Zhengzhou University, Henan, China
| | - Ning Ma
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Zhengzhou University, Henan, China
| | - Donghai Liu
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Zhengzhou University, Henan, China
| | - Weihua Zhang
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Zhengzhou University, Henan, China
| |
Collapse
|
9
|
Fan B, Dun SH, Gu JQ, Guo Y, Ikuyama S. Pycnogenol Attenuates the Release of Proinflammatory Cytokines and Expression of Perilipin 2 in Lipopolysaccharide-Stimulated Microglia in Part via Inhibition of NF-κB and AP-1 Activation. PLoS One 2015; 10:e0137837. [PMID: 26367267 PMCID: PMC4569068 DOI: 10.1371/journal.pone.0137837] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 08/22/2015] [Indexed: 01/29/2023] Open
Abstract
Over activation of microglia results in the production of proinflammatory agents that have been implicated in various brain diseases. Pycnogenol is a patented extract from French maritime pine bark (Pinus pinaster Aiton) with strong antioxidant and anti-inflammatory potency. The present study investigated whether pycnogenol may be associated with the production of proinflammatory mediators in lipopolysaccharide-stimulated BV2 (mouse-derived) microglia. It was found that pycnogenol treatment was dose-dependently associated with significantly less release of nitricoxide (NO), TNF-α, IL-6 and IL-1β, and lower levels of intercellular adhesion molecule1 (ICAM-1) and perilipin 2 (PLIN2). Furthermore, this effect was replicated in primary brain microglia. Levels of inducible NO synthase mRNA and protein were attenuated, whereas there was no change in the production of the anti-inflammatory cytokine IL-10. Further evidence indicated that pycnogenol treatment led to the suppression of NF-κB activation through inhibition of p65 translocation into the nucleus and inhibited DNA binding of AP-1, suggesting that these proinflammatory factors are associated with NF-κB and AP-1. We conclude that pycnogenol exerts anti-inflammatory effects through inhibition of the NF-κB and AP-1pathway, and may be useful as a therapeutic agent in the prevention of diseases caused by over activation of microglia.
Collapse
Affiliation(s)
- Bin Fan
- Department of Neurology, Shengjing Hospital, China Medical University, Shenyang, 110004, P. R. China
- * E-mail:
| | - Sai-Hong Dun
- Department of Neurology, Shengjing Hospital, China Medical University, Shenyang, 110004, P. R. China
| | - Jian-Qiu Gu
- Department of Endocrinology and Metabolism, First Affiliated Hospital, P. R. China Medical University, Shenyang, 110001, P. R. China
| | - Yang Guo
- Department of Neurology, Shengjing Hospital, China Medical University, Shenyang, 110004, P. R. China
| | - Shoichiro Ikuyama
- Department of Clinical Investigation & Department of Endocrine, Metabolic and Rheumatic Diseases, Oita San-ai Medical center, Oita, 870–1151, Japan
| |
Collapse
|
10
|
Li YY, Feng J, Zhang XL, Cui YY. Pine bark extracts: nutraceutical, pharmacological, and toxicological evaluation. J Pharmacol Exp Ther 2015; 353:9-16. [PMID: 25597308 DOI: 10.1124/jpet.114.220277] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Proanthocyanidins are among the most abundant constituents in pine bark extracts (PBEs). This review summarizes medical research on PBEs from Pinus pinaster, Pinus radiata, Pinus massoniana, and other less well characterized species. The precise mechanisms of the important physiologic functions of PBE components remain to be elucidated, but there is evidently great potential for the identification and development of novel antioxidant, anti-inflammatory, cardiovascular, neuroprotective, and anticancer medicines. Although toxicological data for PBEs are limited, no serious adverse effects have been reported. PBEs, therefore, may have potential as nutraceuticals and pharmaceuticals and should be safe for use as food ingredients.
Collapse
Affiliation(s)
- Ying-Ya Li
- Department of Regenerative Medicine (Y.-Y.L., J.F., X.-L.Z., Y.-Y.C.), Key Laboratory of Arrhythmias of the Ministry of Education of China (Y.-Y.C.), and Institute of Medical Genetics (Y.-Y.C.), Tongji University School of Medicine, Shanghai, China
| | - Jiao Feng
- Department of Regenerative Medicine (Y.-Y.L., J.F., X.-L.Z., Y.-Y.C.), Key Laboratory of Arrhythmias of the Ministry of Education of China (Y.-Y.C.), and Institute of Medical Genetics (Y.-Y.C.), Tongji University School of Medicine, Shanghai, China
| | - Xiao-Lu Zhang
- Department of Regenerative Medicine (Y.-Y.L., J.F., X.-L.Z., Y.-Y.C.), Key Laboratory of Arrhythmias of the Ministry of Education of China (Y.-Y.C.), and Institute of Medical Genetics (Y.-Y.C.), Tongji University School of Medicine, Shanghai, China
| | - Ying-Yu Cui
- Department of Regenerative Medicine (Y.-Y.L., J.F., X.-L.Z., Y.-Y.C.), Key Laboratory of Arrhythmias of the Ministry of Education of China (Y.-Y.C.), and Institute of Medical Genetics (Y.-Y.C.), Tongji University School of Medicine, Shanghai, China
| |
Collapse
|
11
|
Fan B, Gu JQ, Yan R, Zhang H, Feng J, Ikuyama S. High glucose, insulin and free fatty acid concentrations synergistically enhance perilipin 3 expression and lipid accumulation in macrophages. Metabolism 2013; 62:1168-79. [PMID: 23566650 DOI: 10.1016/j.metabol.2013.02.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 02/27/2013] [Accepted: 02/28/2013] [Indexed: 01/03/2023]
Abstract
OBJECTIVE Perilipin (PLIN) 3, an intracellular lipid droplet (LD)-associated protein, is implicated in foam cell formation. Since metabolic derangements found in metabolic syndrome, such as high serum levels of glucose, insulin and free fatty acids (FFAs), are major risk factors promoting atherosclerosis, we investigated whether PLIN3 expression is affected by glucose, insulin and oleic acid (OA) using RAW264.7 cells. METHODS Real-time PCR and Western blotting were performed to detect PLIN3 or PLIN2 expression. Oil-red O staining and Lipid Analysis were employed to measure cellular content of triacylglycerides (TAG) and cholesterol. RESULTS PLIN3 mRNA was stimulated by high glucose or insulin concentrations individually, but not by OA. A combination of any two factors did not enhance PLIN3 expression any more than that evoked by glucose alone at 24h. Interestingly, however, simultaneous addition of all three factors synergistically enhanced the PLIN3 expression. This synergistic effect was not apparent for PLIN2 mRNA expression. Inhibitors of Src family tyrosine kinase and/or phosphatidylinositol 3-kinase, both of which are activated by insulin and FFA signaling, partially suppressed PLIN3 expression induced by the combination of the three factors. While simultaneous addition of glucose, insulin and OA remarkably increased the cellular content of TAG and cholesterol, knocking-down of PLIN3 predominantly reduced TAG content. CONCLUSIONS These results indicate that PLIN3 expression is synergistically stimulated by high glucose, insulin and FFA concentrations, in parallel with TAG accumulation in macrophages. This finding raises new evidence of PLIN3 involvement in conversion of macrophages into foam cells.
Collapse
Affiliation(s)
- Bin Fan
- Department of Neurology, Shengjing Hospital, China Medical University, Shenyang 11004, China
| | | | | | | | | | | |
Collapse
|
12
|
Bindesbøll C, Berg O, Arntsen B, Nebb HI, Dalen KT. Fatty acids regulate perilipin5 in muscle by activating PPARδ. J Lipid Res 2013; 54:1949-63. [PMID: 23606724 DOI: 10.1194/jlr.m038992] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The surface of lipid droplets (LDs) in various cell types is coated with perilipin proteins encoded by the Plin genes. Perilipins regulate LD metabolism by selectively recruiting lipases and other proteins to LDs. We have studied the expression of perilipins in mouse muscle. The glycolytic fiber-enriched gastrocnemius muscle expresses predominantly Plin2-4. The oxidative fiber-enriched soleus muscle expresses Plin2-5. Expression of Plin2 and Plin4-5 is elevated in gastrocnemius and soleus muscles from mice fed a high-fat diet. This effect is preserved in peroxisome proliferator-activated receptor (PPAR)α-deficient mice. Mouse muscle derived C2C12 cells differentiated into glycolytic fibers increase transcription of these Plins when exposed to various long chain fatty acids (FAs). To understand how FAs regulate Plin genes, we used specific activators and antagonists against PPARs, Plin promoter reporter assays, chromatin immunoprecipitation, siRNA, and animal models. Our analyses demonstrate that FAs require PPARδ to induce transcription of Plin4 and Plin5. We further identify a functional PPAR binding site in the Plin5 gene and establish Plin5 as a novel direct PPARδ target in muscle. Our study reveals that muscle cells respond to elevated FAs by increasing transcription of several perilipin LD-coating proteins. This induction renders the muscle better equipped to sequester incoming FAs into cytosolic LDs.
Collapse
Affiliation(s)
- Christian Bindesbøll
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | | | | | | | | |
Collapse
|
13
|
Dynamics and regulation of lipid droplet formation in lipopolysaccharide (LPS)-stimulated microglia. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:607-17. [DOI: 10.1016/j.bbalip.2012.01.007] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 12/04/2011] [Accepted: 01/10/2012] [Indexed: 01/22/2023]
|
14
|
Xie X, Wang S, Xiao L, Zhang J, Wang J, Liu J, Shen X, He D, Zheng X, Zhai Y. DBZ blocks LPS-induced monocyte activation and foam cell formation via inhibiting nuclear factor-ĸB. Cell Physiol Biochem 2011; 28:649-62. [PMID: 22178877 DOI: 10.1159/000335760] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/24/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS It has been widely accepted that chronic inflammation plays important roles in the atherogenesis. Danshensu Bingpian Zhi (DBZ) is a novel synthetic compound derived from the traditional Chinese medicine (TCM) formula Fu Fang Dan Shen (FFDS), which is effective on atherosclerosis clinically. We hypothesized that DBZ possessed the anti-atherosclerosis potentials. Here, we examined the inhibitory effects of DBZ on LPS-induced monocyte activation and foam cell formation. METHODS The effects of DBZ were assessed on LPS-induced inflammatory factors expression in monocyte/macrophage. Activation of NF-κB and AP-1 was analyzed by luciferase reporter assay and signaling pathway of NF-κB was investigated to elucidate mechanisms underlying DBZ mediated anti-inflammatory activity. Effects of DBZ on macrophage lipid accumulation were evaluated in native LDL and LPS co-incubated macrophages. RESULTS DBZ inhibited LPS-induced inflammatory factors expression dose dependently in monocytes. DBZ inhibited NF-κB activation strongly and AP-1 slightly. DBZ suppressed the LPS-induced degradation of IκBα, thereby decreasing the translocation of p65 to nucleus. Furthermore, DBZ suppressed LPS-activated macrophages lipid accumulation, partly due to inhibiting the expression of LPS-induced aP2 and ADRP in macrophges. CONCLUSION These results demonstrate that DBZ has potentials on anti-atherosclerosis by suppressing monocyte activation and foam cell formation.
Collapse
Affiliation(s)
- Xinni Xie
- Key Laboratory for Cell Proliferation and Regulation Biology of State Education Ministry and College of Life Sciences, Beijing Normal University, Beijing, P.R. China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Gu JQ, Wang DF, Yan XG, Zhong WL, Zhang J, Fan B, Ikuyama S. A Toll-like receptor 9-mediated pathway stimulates perilipin 3 (TIP47) expression and induces lipid accumulation in macrophages. Am J Physiol Endocrinol Metab 2010; 299:E593-600. [PMID: 20628022 DOI: 10.1152/ajpendo.00159.2010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Excessive accumulation of lipids in macrophages results in formation of foam cells and is a hallmark of atherosclerosis. The PAT family of proteins has been implicated in this process, but details of their involvement in foam cell formation have not been fully elucidated. One of dominant members of the PAT proteins, perilipin 3 (TIP47), is likely to be involved in such a regulatory mechanism. In this study, we demonstrated that the Toll-like receptor 9 (TLR9)-mediated pathway stimulates perilipin 3 expression and accumulation of lipids, especially triglycerides, in macrophages. Oligodeoxynucleotide (ODN) 1826, a ligand of TLR9, significantly enhanced perilipin 3 expression in RAW264.7 cells, and chloroquine, a TLR9 inhibitor, almost completely inhibited ODN1826-induced perilipin 3 expression. The inhibitors of c-jun NH2-terminal kinase and PI 3-kinase suppressed the level of perilipin 3 mRNA induced by ODN1826. ODN1826 induced the expression of IL-1α and IFNβ, both of which increased perilipin 3 expression. Antibodies against these cytokines suppressed the ODN1826-induced perilipin 3 mRNA levels. These results suggest that the expression of perilipin 3 in macrophages is in part regulated through the TLR9-mediated mechanism. Furthermore, ODN1826 increased intracellular lipid accumulation in the presence of oxLDL, which was reduced by perilipin 3 siRNA. Perilipin 3 expression was not stimulated by oxLDL. Depletion of perilipin 3 by siRNA specifically reduced triglyceride content in the cells but not cholesterol content, indicating that perilipin 3 is involved mainly in triglyceride accumulation. In conclusion, the TLR9-mediated pathway facilitates foam cell formation in part through increased expression of perilipin 3.
Collapse
Affiliation(s)
- Jian-Qiu Gu
- Dept. of Endocrinology and Metabolism, The First Affiliated Hospital of China Medical University, No. 155, North Nanjing St., Heping District, Shenyang 110001, China.
| | | | | | | | | | | | | |
Collapse
|
16
|
Song X, Kusakari Y, Xiao CY, Kinsella SD, Rosenberg MA, Scherrer-Crosbie M, Hara K, Rosenzweig A, Matsui T. mTOR attenuates the inflammatory response in cardiomyocytes and prevents cardiac dysfunction in pathological hypertrophy. Am J Physiol Cell Physiol 2010; 299:C1256-66. [PMID: 20861467 DOI: 10.1152/ajpcell.00338.2010] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Previous studies have suggested that inhibition of the mammalian target of rapamycin (mTOR) by rapamycin suppresses myocardial hypertrophy. However, the role of mTOR in the progression of cardiac dysfunction in pathological hypertrophy has not been fully defined. Interestingly, recent reports indicate that the inflammatory response, which plays an important role in the development of heart failure, is enhanced by rapamycin under certain conditions. Our aim in this study was to determine the influence of mTOR on pathological hypertrophy and to assess whether cardiac mTOR regulates the inflammatory response. We generated transgenic mice with cardiac-specific overexpression of wild-type mTOR (mTOR-Tg). mTOR-Tg mice were protected against cardiac dysfunction following left ventricular pressure overload induced by transverse aortic constriction (TAC) (P < 0.01) and had significantly less interstitial fibrosis compared with littermate controls (WT) at 4 wk post-TAC (P < 0.01). In contrast, TAC caused cardiac dysfunction in WT. At 1 wk post-TAC, the proinflammatory cytokines interleukin (IL)-1β and IL-6 were significantly increased in WT mice but not in mTOR-Tg mice. To further characterize the effects of mTOR activation, we exposed HL-1 cardiomyocytes transfected with mTOR to lipopolysaccharide (LPS). mTOR overexpression suppressed LPS-induced secretion of IL-6 (P < 0.001), and the mTOR inhibitors rapamycin and PP242 abolished this inhibitory effect of mTOR. In addition, mTOR overexpression reduced NF-κB-regulated transcription in HL-1 cells. These data suggest that mTOR mitigates adverse outcomes of pressure overload and that this cardioprotective effect of mTOR is mediated by regulation of the inflammatory reaction.
Collapse
Affiliation(s)
- Xiaoxiao Song
- Cardiovascular Institute, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
The expression and functions of toll-like receptors in atherosclerosis. Mediators Inflamm 2010; 2010:393946. [PMID: 20652007 PMCID: PMC2905957 DOI: 10.1155/2010/393946] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 04/07/2010] [Indexed: 12/16/2022] Open
Abstract
Inflammation drives atherosclerosis. Both immune and resident vascular cell types are involved in the development of atherosclerotic lesions. The phenotype and function of these cells are key in determining the development of lesions. Toll-like receptors are the most characterised innate immune receptors and are responsible for the recognition of exogenous conserved motifs on pathogens, and, potentially, some endogenous molecules. Both endogenous and exogenous TLR agonists may be present in atherosclerotic plaques. Engagement of toll-like receptors on immune and resident vascular cells can affect atherogenesis as signalling downstream of these receptors can elicit proinflammatory cytokine release, lipid uptake, and foam cell formation and activate cells of the adaptive immune system. In this paper, we will describe the expression of TLRs on immune and resident vascular cells, highlight the TLR ligands that may act through TLRs on these cells, and discuss the consequences of TLR activation in atherosclerosis.
Collapse
|
18
|
Feingold KR, Kazemi MR, Magra AL, McDonald CM, Chui LG, Shigenaga JK, Patzek SM, Chan ZW, Londos C, Grunfeld C. ADRP/ADFP and Mal1 expression are increased in macrophages treated with TLR agonists. Atherosclerosis 2009; 209:81-8. [PMID: 19748622 DOI: 10.1016/j.atherosclerosis.2009.08.042] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Revised: 08/17/2009] [Accepted: 08/24/2009] [Indexed: 11/27/2022]
Abstract
Activation of macrophages by TLR agonists enhances foam cell formation, but the underlying mechanisms are not understood. We examined the effects of TLR agonists on ADRP/ADFP, a protein associated with forming lipid droplets, and Mal1 a fatty acid-binding protein, in two mouse macrophage cell lines and human monocytes. Low doses of LPS, a TLR4 agonist increased both mRNA and protein levels of ADRP/ADFP and Mal1 in RAW 264.7 macrophages. Following pretreatment with Intralipid, fatty acids, or acetyl-LDL to increase triglyceride or cholesterol ester storage, LPS treatment still increased ADRP/ADFP and Mal1 mRNA levels. LPS also induced ADRP/ADFP and Mal1 in J774 macrophages and ADRP/ADFP in human monocytes. Zymosan, a fungal product that activates TLR2, poly-I:C, a viral mimetic that activates TLR3, and imiquimod, a TLR7 agonist, also increased ADRP/ADFP. Zymosan, but not poly-I:C or imiquimod, induced Mal1. In contrast, neither gene was induced by TNFalpha, IL-1beta, IL-6, or interferon-gamma. Thus TLR agonists induce ADRP/ADFP and Mal1, which likely contributes to macrophage triglyceride and cholesterol ester storage leading to foam cell formation.
Collapse
Affiliation(s)
- Kenneth R Feingold
- Metabolism Section, Department of Veterans Affairs Medical Center, San Francisco, CA 94121, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Fan B, Ikuyama S, Gu JQ, Wei P, Oyama JI, Inoguchi T, Nishimura J. Oleic acid-induced ADRP expression requires both AP-1 and PPAR response elements, and is reduced by Pycnogenol through mRNA degradation in NMuLi liver cells. Am J Physiol Endocrinol Metab 2009; 297:E112-23. [PMID: 19383873 DOI: 10.1152/ajpendo.00119.2009] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Fatty acids stimulate lipid accumulation in parallel with increased expression of adipose differentiation-related protein (ADRP) in liver cells. Although it is generally considered that the fatty acid effect on ADRP expression is mediated by peroxisome proliferator-activated receptors (PPARs), we identified here an additional molecular mechanism using the NMuLi mouse liver nonparenchymal cell line, which expresses PPARgamma and delta but not alpha. Oleic acid (OA) and specific ligands for PPARgamma and -delta stimulated ADRP expression as well as the -2,090-bp ADRP promoter activity which encompasses the PPAR response element (PPRE) adjacent to an Ets/activator protein (AP)-1 site. When the AP-1 site was mutated, OA failed to stimulate the activity despite the presence of the PPRE, whereas ligands for PPARgamma and -delta did stimulate it and so did a PPARalpha ligand under the coexpression of PPARalpha. DNA binding of AP-1 was stimulated by OA but not by PPAR ligands. Because we previously demonstrated that Pycnogenol (PYC), a French maritime pine bark extract, suppressed ADRP expression in macrophages partly by suppression of AP-1 activity, we tested the effect of PYC on NMuLi cells. PYC reduced the OA-induced ADRP expression along with suppression of lipid droplet formation. However, PYC neither suppressed the OA-stimulated ADRP promoter activity nor DNA binding of AP-1 but, instead, reduced the ADRP mRNA half-life. All these results indicate that the effect of OA on ADRP expression requires AP-1 as well as PPRE, and PYC suppresses the ADRP expression in part by facilitating mRNA degradation. PYC, a widely used dietary supplement, could be beneficial for the prevention of excessive lipid accumulation such as hepatic steatosis.
Collapse
Affiliation(s)
- Bin Fan
- Division of Clinical Immunology, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Beppu 874-0838, Japan
| | | | | | | | | | | | | |
Collapse
|