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Zeng R, Xiong Y, Zhu F, Ma Z, Liao W, He Y, He J, Li W, Yang J, Lu Q, Xu G, Yao Y. Fenofibrate attenuated glucose-induced mesangial cells proliferation and extracellular matrix synthesis via PI3K/AKT and ERK1/2. PLoS One 2013; 8:e76836. [PMID: 24130796 PMCID: PMC3793917 DOI: 10.1371/journal.pone.0076836] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 09/03/2013] [Indexed: 11/25/2022] Open
Abstract
Excess mesangial extracellular matrix (ECM) and mesangial cell proliferation is the major pathologic feature of diabetic nephropathy (DN). Fenofibrate, a PPARα agonist, has been shown to attenuate extracellular matrix formation in diabetic nephropathy. However, the mechanisms underlying this effect remain to be elucidated. In this study, the effect of fenofibrate on high-glucose induced cell proliferation and extracellular matrix exertion and its mechanisms were investigated in cultured rat mesangial cells by the methylthiazoletetrazolium (MTT) assay, flow cytometry and western blot. The results showed that treatment of mesangial cells (MCs) with fenofibrate repressed high-glucose induced up-regulation of extracellular matrix Collagen-IV, and inhibited entry of cell cycle into the S phase. This G1 arrest and ECM inhibition was caused by the reduction of phosphorylation and activation of extracellular signal-regulated kinase 1/2 (ERK1/2) and AKT. On the contrary, PPARα siRNA accelerated high glucose-induced cell cycle progression by ERK1/2 and AKT activation. Taken together, fenofibrate ameliorated glucose-induced mesangial cell proliferation and matrix production via its inhibition of PI3K/AKT and ERK1/2 signaling pathways. Such mechanisms may contribute to the favorable effects of treatment using fenofibrate in diabetic nephropathy.
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Affiliation(s)
- Rui Zeng
- Division of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yan Xiong
- Division of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Division of Nephrology, Wuhan No.4 hospital, Wuhan, Hubei, China
| | - Fengming Zhu
- Division of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Zufu Ma
- Division of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Wenhui Liao
- Department of Geriatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yong He
- Division of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Division of Nephrology, Wuhan No.5 hospital, Wuhan, Hubei, China
| | - JinSeng He
- Division of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Wei Li
- Division of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Juan Yang
- Division of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Qian Lu
- Division of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Gang Xu
- Division of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- * E-mail: (YY); (GX)
| | - Ying Yao
- Division of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- * E-mail: (YY); (GX)
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Seok H, Cha BS. Refocusing Peroxisome Proliferator Activated Receptor-α: A New Insight for Therapeutic Roles in Diabetes. Diabetes Metab J 2013; 37:326-32. [PMID: 24199160 PMCID: PMC3816132 DOI: 10.4093/dmj.2013.37.5.326] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Although glucose-lowering treatment shows some risk lowering effects in cardiovascular diseases, risks of macrovascular and microvascular complications have still remained, and development of new therapeutic strategies is needed. Recent data have shown that peroxisome proliferator activated receptor-α (PPAR-α) plays a pivotal role in the regulation of lipid homeostasis, fatty acid oxidation, cellular differentiation, and immune response such as inflammation or vascularization related to diabetic complication. This review will re-examine the metabolic role of PPAR-α, summarize data from clinical studies on the effect of PPAR-α agonist in diabetes, and will discuss the possible therapeutic role of PPAR-α activation.
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Affiliation(s)
- Hannah Seok
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Bong Soo Cha
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
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Kostapanos MS, Kei A, Elisaf MS. Current role of fenofibrate in the prevention and management of non-alcoholic fatty liver disease. World J Hepatol 2013; 5:470-478. [PMID: 24073298 PMCID: PMC3782684 DOI: 10.4254/wjh.v5.i9.470] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Revised: 07/24/2013] [Accepted: 08/20/2013] [Indexed: 02/06/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a common health problem with a high mortality burden due to its liver- and vascular-specific complications. It is associated with obesity, high-fat diet as well as with type 2 diabetes mellitus (T2DM) and metabolic syndrome (MetS). Impaired hepatic fatty acid (FA) turnover together with insulin resistance are key players in NAFLD pathogenesis. Peroxisome proliferator-activated receptors (PPARs) are involved in lipid and glucose metabolic pathways. The novel concept is that the activation of the PPARα subunit may protect from liver steatosis. Fenofibrate, by activating PPARα, effectively improves the atherogenic lipid profile associated with T2DM and MetS. Experimental evidence suggested various protective effects of the drug against liver steatosis. Namely, fenofibrate-related PPARα activation may enhance the expression of genes promoting hepatic FA β-oxidation. Furthermore, fenofibrate reduces hepatic insulin resistance. It also inhibits the expression of inflammatory mediators involved in non-alcoholic steatohepatitis pathogenesis. These include tumor necrosis factor-α, intercellular cell adhesion molecule-1, vascular cell adhesion molecule-1 and monocyte chemoattractant protein-1. Consequently, fenofibrate can limit hepatic macrophage infiltration. Other liver-protective effects include decreased oxidative stress and improved liver microvasculature function. Experimental studies showed that fenofibrate can limit liver steatosis associated with high-fat diet, T2DM and obesity-related insulin resistance. Few studies showed that these benefits are also relevant even in the clinical setting. However, these have certain limitations. Namely, these were uncontrolled, their sample size was small, fenofibrate was used as a part of multifactorial approach, while histological data were absent. In this context, there is a need for large prospective studies, including proper control groups and full assessment of liver histology.
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54
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Pathogenic role of diabetes-induced PPAR-α down-regulation in microvascular dysfunction. Proc Natl Acad Sci U S A 2013; 110:15401-6. [PMID: 24003152 DOI: 10.1073/pnas.1307211110] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Two independent clinical studies have reported that fenofibrate, a peroxisome proliferator-activated receptor α (PPARα) agonist, has robust therapeutic effects on microvascular complications of diabetes, including diabetic retinopathy (DR) in type 2 diabetic patients. However, the expression and function of PPARα in the retina are unclear. Here, we demonstrated that PPARα is expressed in multiple cell types in the retina. In both type 1 and type 2 diabetes models, expression of PPARα, but not PPARβ/δ or PPARγ, was significantly down-regulated in the retina. Furthermore, high-glucose medium was sufficient to down-regulate PPARα expression in cultured retinal cells. To further investigate the role of PPARα in DR, diabetes was induced in PPARα knockout (KO) mice and wild-type (WT) mice. Diabetic PPARα KO mice developed more severe DR, as shown by retinal vascular leakage, leukostasis, pericyte loss, capillary degeneration, and over-expression of inflammatory factors, compared with diabetic WT mice. In addition, overexpression of PPARα in the retina of diabetic rats significantly alleviated diabetes-induced retinal vascular leakage and retinal inflammation. Furthermore, PPARα overexpression inhibited endothelial cell migration and proliferation. These findings revealed that diabetes-induced down-regulation of PPARα plays an important role in DR. Up-regulation or activation of PPARα may represent a novel therapeutic strategy for DR.
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Subramani PA, Panati K, Narala VR. Molecular docking of Glyceroneogenesis pathway intermediates with Peroxisome Proliferator- Activated Receptor-Alpha (PPAR-α). Bioinformation 2013; 9:629-32. [PMID: 23904740 PMCID: PMC3725004 DOI: 10.6026/97320630009629] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 06/08/2013] [Indexed: 02/06/2023] Open
Abstract
Peroxisome proliferator-activated receptor alpha (PPAR-α) belongs to the nuclear receptor superfamily of proteins. It is one of the principle regulators of metabolism and lipid homeostasis whose malfunction leads to complications including obesity and type 2 diabetes. In the adipose tissue, glyceroneogenesis is a unique pathway through which pyruvate is converted into glycerol-3- phosphate (G3P) in a multistep process. Previous findings demonstrated that glyceroneogenesis regulates triacylglycerol synthesis and adipogenesis. This led us to hypothesize that one of the pathway intermediate is physiologically relevant PPAR-α ligand. In the present study using in silico docking, we proved that glycerate, dihydroxy acetone phosphate, glyceraldehyde-3-phosphate, and G3P are key glyceroneogenesis pathway intermediates which bind to PPAR-α. They bind PPAR-α with comparable binding energy and docking score to that of (2s)-2-ethoxy-3-[4-(2-{4-[(methylsulfonyl)oxy]phenyl}ethoxy)phenyl]propanoic acid(AZ-2), a synthetic high affinity ligand of PPAR-α. These intermediates could be studied further as potential physiologically relevant activators of PPAR-α in vitro and in vivo.
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Liu GL, Zhang YM, Dai DZ, Ding MJ, Cong XD, Dai Y. Male hypogonadism induced by high fat diet and low dose streptozotocin is mediated by activated endoplasmic reticulum stress and IκBβ and attenuated by argirein and valsartan. Eur J Pharmacol 2013; 713:78-88. [DOI: 10.1016/j.ejphar.2013.04.030] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2012] [Revised: 04/19/2013] [Accepted: 04/26/2013] [Indexed: 12/19/2022]
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Dana N, Javanmard SH, Fazilati M, Pilehvarian AA. A comparison of peroxisome proliferator-activated receptor-α agonist and antagonist on human umbilical vein endothelial cells angiogenesis. Adv Biomed Res 2013; 2:54. [PMID: 24223369 PMCID: PMC3814543 DOI: 10.4103/2277-9175.115792] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 10/23/2012] [Indexed: 12/16/2022] Open
Abstract
Background: There are controversial reports about the antiangiogenic effects of peroxisome proliferator-activated receptor α (PPARα). In the current study, we compared the effects of PPARα agonist and antagonist on human umbilical vein endothelial cells (HUVECs) angiogenesis with matrigel assay. Materials and Methods: HUVECs (1 × 105 cells/well) treated with PPARα agonist (fenofibrate) and antagonist (GW6471) were cultured on matrigel for 24 h. Treated cells were stained with calcein and investigated by fluorescent microscopy. The obtained images were also analyzed by AngioQuant software. Finally, the data were analyzed using SPSS 15 software, Kruskal-Wallis and one way ANOVA. Results: Statistical analysis showed that fenofibrate significantly inhibit the tube formation (size, length, junction) (P < 0.05) but there was a trend to increased angiogenesis in GW6471 treated group (P > 0.05). Conclusion: These results showed that PPARα agonist is effective in suppression of angiogenesis. Further studies are needed to confirm these results in in vivo studies.
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Affiliation(s)
- Nasim Dana
- Department of Physiology, Physiology Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
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58
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Contreras AV, Torres N, Tovar AR. PPAR-α as a key nutritional and environmental sensor for metabolic adaptation. Adv Nutr 2013; 4:439-52. [PMID: 23858092 PMCID: PMC3941823 DOI: 10.3945/an.113.003798] [Citation(s) in RCA: 161] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs) are transcription factors that belong to the superfamily of nuclear hormone receptors and regulate the expression of several genes involved in metabolic processes that are potentially linked to the development of some diseases such as hyperlipidemia, diabetes, and obesity. One type of PPAR, PPAR-α, is a transcription factor that regulates the metabolism of lipids, carbohydrates, and amino acids and is activated by ligands such as polyunsaturated fatty acids and drugs used to treat dyslipidemias. There is evidence that genetic variants within the PPARα gene have been associated with a risk of the development of dyslipidemia and cardiovascular disease by influencing fasting and postprandial lipid concentrations; the gene variants have also been associated with an acceleration of the progression of type 2 diabetes. The interactions between genetic PPARα variants and the response to dietary factors will help to identify individuals or populations who can benefit from specific dietary recommendations. Interestingly, certain nutritional conditions, such as the prolonged consumption of a protein-restricted diet, can produce long-lasting effects on PPARα gene expression through modifications in the methylation of a specific locus surrounding the PPARα gene. Thus, this review underlines our current knowledge about the important role of PPAR-α as a mediator of the metabolic response to nutritional and environmental factors.
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Affiliation(s)
- Alejandra V. Contreras
- Faculty of Medicine, National University Autonomous of Mexico, PhD Program in Biomedical Sciences,National Institute of Genomic Medicine
| | - Nimbe Torres
- Nutrition Physiology Department, National Institute of Medical Sciences and Nutrition Salvador Zubirán, Mexico D.F. Mexico
| | - Armando R. Tovar
- Nutrition Physiology Department, National Institute of Medical Sciences and Nutrition Salvador Zubirán, Mexico D.F. Mexico,To whom correspondence should be addressed. E-mail:
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Yang CS, Yuk JM, Kim JJ, Hwang JH, Lee CH, Kim JM, Oh GT, Choi HS, Jo EK. Small heterodimer partner-targeting therapy inhibits systemic inflammatory responses through mitochondrial uncoupling protein 2. PLoS One 2013; 8:e63435. [PMID: 23704907 PMCID: PMC3660347 DOI: 10.1371/journal.pone.0063435] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 03/28/2013] [Indexed: 01/15/2023] Open
Abstract
The orphan nuclear receptor, small heterodimer partner (SHP), appears to play a negative regulatory role in innate immune signaling. Emerging evidence warrants further study on the therapeutic targeting of SHP to suppress excessive and deleterious inflammation. Here we show that fenofibrate, which targets SHP, is required for inhibiting systemic inflammation via mitochondrial uncoupling protein 2 (UCP2). In vivo administration of fenofibrate ameliorated systemic inflammatory responses and increased survival upon experimental sepsis through SHP. An abundance of SHP was observed in mice fed fenofibrate and in cultured macrophages through LKB1-dependent activation of the AMP-activated protein kinase pathway. Fenofibrate significantly blocked endotoxin-triggered inflammatory signaling responses via SHP, but not via peroxisome proliferator-activated receptor (PPAR)-α. In addition to the known mechanism by which SHP modulates innate signaling, we identify a new role of fenofibrate-induced SHP on UCP2 induction, which is required for the suppression of inflammatory responses through modulation of mitochondrial ROS production. These data strongly suggest that the SHP-inducing drug fenofibrate paves the way for novel therapies for systemic inflammation by targeting SHP.
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Affiliation(s)
- Chul-Su Yang
- Department of Microbiology, Chungnam National University School of Medicine, Daejeon, S. Korea
- Infection Signaling Network Research Center, Chungnam National University School of Medicine, Daejeon, S. Korea
| | - Jae-Min Yuk
- Department of Microbiology, Chungnam National University School of Medicine, Daejeon, S. Korea
- Infection Signaling Network Research Center, Chungnam National University School of Medicine, Daejeon, S. Korea
| | - Jwa-Jin Kim
- Department of Microbiology, Chungnam National University School of Medicine, Daejeon, S. Korea
- Infection Signaling Network Research Center, Chungnam National University School of Medicine, Daejeon, S. Korea
| | - Jung Hwan Hwang
- Laboratory Animal Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, S. Korea
| | - Chul-Ho Lee
- Laboratory Animal Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, S. Korea
| | - Jin-Man Kim
- Department of Pathology, Chungnam National University School of Medicine, Daejeon, S. Korea
- Infection Signaling Network Research Center, Chungnam National University School of Medicine, Daejeon, S. Korea
| | - Goo Taeg Oh
- Division of Life and Pharmaceutical Science, Ewha Womans University, Seoul, S. Korea
| | - Hueng-Sik Choi
- National Creative Research Initiatives Center for Nuclear Receptor Signals, Hormone Research Center, School of Biological Sciences and Technology, Chonnam National University, Gwangju, S. Korea
| | - Eun-Kyeong Jo
- Department of Microbiology, Chungnam National University School of Medicine, Daejeon, S. Korea
- Infection Signaling Network Research Center, Chungnam National University School of Medicine, Daejeon, S. Korea
- * E-mail:
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Kostapanos MS, Florentin M, Elisaf MS. Fenofibrate and the kidney: an overview. Eur J Clin Invest 2013; 43:522-31. [PMID: 23480615 DOI: 10.1111/eci.12068] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 02/11/2013] [Indexed: 12/18/2022]
Abstract
BACKGROUND Fenofibrate has been used for the management of atherogenic dyslipidaemia for many years. Reports of fenofibrate-associated increases in serum creatinine (SCr) levels raised concerns regarding deleterious effects on renal function. DESIGN In this narrative review, we discuss available literature on the effect of fenofibrate on the kidney. RESULTS Most clinical studies showed a rapid (within weeks) raising effect of fenofibrate on SCr levels. This was often accompanied by declined estimated glomerular filtration rate. Risk predictors of this adverse effect might include increased age, impaired renal function and high-dose treatment. Also, the concomitant use of medications affecting renal hemodynamics (e.g. angiotensin-converting enzyme-inhibitors (ACEi) and angiotensin receptor blockers) may predispose to fenofibrate-associated increased SCr levels. Interestingly, SCr increases by fenofibrate were transient and reversible even without treatment discontinuation. Furthermore, fenofibrate was associated with a slower progression of renal function impairment and albuminuria in a long-term basis. Also, fenofibrate might be protective against pathological changes in diabetic nephropathy and hypertensive glomerulosclerosis. In this context, it is uncertain whether fenofibrate-associated increase in SCr levels mirrors true renal function deterioration. Several theories have been expressed. The most dominant one involved the inhibition of renal vasodilatory prostaglandins reducing renal plasma flow and glomerular pressure. Increased creatinine secretion or reduced creatinine clearance by fenofibrate was also suggested. These hypotheses should be settled by further studies. CONCLUSIONS Fenofibrate may not be a nephrotoxic drug. However, a close monitoring of SCr levels is relevant especially in high-risk patients. Increases in SCr levels ≥30% can impose treatment discontinuation.
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Affiliation(s)
- Michael S Kostapanos
- Department of Internal Medicine, Medical School, University of Ioannina, Ioannina, Greece
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61
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Bak EJ, Kim J, Choi YH, Kim JH, Lee DE, Woo GH, Cha JH, Yoo YJ. Wogonin ameliorates hyperglycemia and dyslipidemia via PPARα activation in db/db mice. Clin Nutr 2013; 33:156-63. [PMID: 23623334 DOI: 10.1016/j.clnu.2013.03.013] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 03/06/2013] [Accepted: 03/18/2013] [Indexed: 11/18/2022]
Abstract
BACKGROUND & AIMS Wogonin is a flavonoid extracted from the root of Scutellaria baicalensis Gerogi. We evaluated the therapeutic effects of wogonin using db/db mice. METHODS Mice received wogonin or vehicle by oral gavage for 2 weeks. Blood glucose, insulin, and cholesterol levels were measured, and liver morphology was observed with histopathological analysis. The mRNA expression levels of PPARα, PPARγ, and adiponectin in the liver and white adipose tissue (WAT) were determined by real-time PCR. Immunoblotting for AMPK and PPARγ, and adipocyte differentiation were investigated in vitro using 3T3-L1 cells. A luciferase assay was used to measure PPARα and PPARγ binding activity. RESULTS The wogonin group showed decreased weight gain without a change in food intake and improved glucose tolerance. Serum insulin and cholesterol levels in the wogonin group were significantly decreased compared to those in the control group. The wogonin group also showed less accumulation of lipid droplets and glycogen in the liver. PPARα and PPARγ expression levels in the liver and WAT and adiponectin expression level in WAT in the wogonin group were higher than those in the control group. In 3T3-L1 cells, wogonin was shown to stimulate AMPK activation in a dose-dependent manner. The presence of wogonin did not affect adipocyte differentiation or PPARγ protein level during adipogenesis. Notably, wogonin enhanced PPARα but not PPARγ transactivation. CONCLUSIONS These indicate that wogonin may have beneficial effects on glucose and lipid metabolism related to enhanced PPARα and adiponectin expression via AMPK activation. Importantly, wogonin did not cause deleterious effects, such as weight gain and fatty liver. Wogonin might be a useful therapeutic agent to treat type 2 diabetes.
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Affiliation(s)
- Eun-Jung Bak
- Oral Cancer Research Institute, Yonsei University College of Dentistry, Seoul, Republic of Korea
| | - Jinmoon Kim
- Research Center for Orofacial Hard Tissue Regeneration, College of Dentistry, Yonsei University, Seoul, Republic of Korea; Department of Applied Life Science, Yonsei University Graduate School, Seoul, Republic of Korea; Department of Oral Biology, Yonsei University College of Dentistry, Seoul, Republic of Korea
| | - Yun Hui Choi
- Department of Applied Life Science, Yonsei University Graduate School, Seoul, Republic of Korea; Department of Oral Biology, Yonsei University College of Dentistry, Seoul, Republic of Korea
| | - Ji-Hye Kim
- Research Center for Orofacial Hard Tissue Regeneration, College of Dentistry, Yonsei University, Seoul, Republic of Korea; Department of Applied Life Science, Yonsei University Graduate School, Seoul, Republic of Korea; Department of Oral Biology, Yonsei University College of Dentistry, Seoul, Republic of Korea
| | - Dong-Eun Lee
- Research Center for Orofacial Hard Tissue Regeneration, College of Dentistry, Yonsei University, Seoul, Republic of Korea; Department of Applied Life Science, Yonsei University Graduate School, Seoul, Republic of Korea; Department of Oral Biology, Yonsei University College of Dentistry, Seoul, Republic of Korea
| | - Gye-Hyeong Woo
- Department of Clinical Science, Semyung University, Jecheon, Republic of Korea
| | - Jeong-Heon Cha
- Oral Cancer Research Institute, Yonsei University College of Dentistry, Seoul, Republic of Korea; Research Center for Orofacial Hard Tissue Regeneration, College of Dentistry, Yonsei University, Seoul, Republic of Korea; Department of Applied Life Science, Yonsei University Graduate School, Seoul, Republic of Korea; Department of Oral Biology, Yonsei University College of Dentistry, Seoul, Republic of Korea
| | - Yun-Jung Yoo
- Research Center for Orofacial Hard Tissue Regeneration, College of Dentistry, Yonsei University, Seoul, Republic of Korea; Department of Applied Life Science, Yonsei University Graduate School, Seoul, Republic of Korea; Department of Oral Biology, Yonsei University College of Dentistry, Seoul, Republic of Korea.
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Bryan S, Baregzay B, Spicer D, Singal PK, Khaper N. Redox-inflammatory synergy in the metabolic syndrome. Can J Physiol Pharmacol 2013; 91:22-30. [PMID: 23368637 DOI: 10.1139/cjpp-2012-0295] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Metabolic syndrome (MetS) comprises interrelated disease states including obesity, insulin resistance and type 2 diabetes (T2DM), dyslipidemia, and hypertension. Essential to normal physiological function, and yet massively damaging in excess, oxidative stress and inflammation are pivotal common threads among the pathologies of MetS. Increasing evidence indicates that redox and inflammatory dysregulation parallels the syndrome's physiological, biochemical, and anthropometric features, leading many to consider the pro-oxidative, pro-inflammatory milieu an unofficial criterion in itself. Left unchecked, cross-promotion of oxidative stress and inflammation creates a feed-forward cycle that can initiate and advance disease progression. Such redox-inflammatory integration is evident in the pathogenesis of obesity, insulin resistance and T2DM, atherogenic dyslipidemia, and hypertension, and is thus hypothesized to be the "common soil" from which they develop. The present review highlights the synergistic contributions of redox-inflammatory processes to each of the components of the MetS.
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Affiliation(s)
- Sean Bryan
- Medical Sciences Division, Northern Ontario School of Medicine, 955 Oliver Road, Lakehead University, Thunder Bay, ON P7B 5E1, Canada
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63
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Structural Features and Transcriptional Activity of Chicken PPARs (α, β, and γ). PPAR Res 2013; 2013:186312. [PMID: 23346099 PMCID: PMC3549339 DOI: 10.1155/2013/186312] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 12/11/2012] [Accepted: 12/12/2012] [Indexed: 11/17/2022] Open
Abstract
While an understanding of lipid metabolism in chickens is critical for a further improvement of food production, there are few studies concerning differences in lipid metabolism mechanisms between chickens and other species at a molecular level. Chickens have three PPAR gene subtypes (α, β, and γ) that function differently from those present in humans and mice. The chicken PPAR-gamma (cPPARγ) gene is shorter than that in humans and lacks a γ2 isoform. Moreover, in serum-free media, cPPARγ shows high transcriptional activity without exogenous ligands. Luciferase reporter assays were used to examine the effect of sera on cPPAR transcriptional activities and showed that adult bovine serum and chicken serum highly activate cPPARα and β functions. Moreover, we found that bezafibrate induces the transactivation function of cPPARβ, but not human PPARδ (human PPARβ ortholog). This ligand selectivity relies on one amino acid residue (chicken: Val419, human: Met444). These results show the possibilities for unique functions of cPPARs on chicken-specific lipid glucose metabolism. As such, a better understanding of the molecular mechanisms of lipid metabolism in chickens could result in higher productivity for the poultry industry.
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Abcouwer SF. Direct effects of PPARα agonists on retinal inflammation and angiogenesis may explain how fenofibrate lowers risk of severe proliferative diabetic retinopathy. Diabetes 2013; 62:36-8. [PMID: 23258912 PMCID: PMC3526047 DOI: 10.2337/db12-1223] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Steven F Abcouwer
- Department of Ophthalmology and Visual Sciences, University of Michigan College of Medicine, Kellogg Eye Center, Ann Arbor, Michigan, USA.
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65
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Chen Y, Hu Y, Lin M, Jenkins AJ, Keech AC, Mott R, Lyons TJ, Ma JX. Therapeutic effects of PPARα agonists on diabetic retinopathy in type 1 diabetes models. Diabetes 2013; 62:261-72. [PMID: 23043158 PMCID: PMC3526044 DOI: 10.2337/db11-0413] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Retinal vascular leakage, inflammation, and neovascularization (NV) are features of diabetic retinopathy (DR). Fenofibrate, a peroxisome proliferator-activated receptor α (PPARα) agonist, has shown robust protective effects against DR in type 2 diabetic patients, but its effects on DR in type 1 diabetes have not been reported. This study evaluated the efficacy of fenofibrate on DR in type 1 diabetes models and determined if the effect is PPARα dependent. Oral administration of fenofibrate significantly ameliorated retinal vascular leakage and leukostasis in streptozotocin-induced diabetic rats and in Akita mice. Favorable effects on DR were also achieved by intravitreal injection of fenofibrate or another specific PPARα agonist. Fenofibrate also ameliorated retinal NV in the oxygen-induced retinopathy (OIR) model and inhibited tube formation and migration in cultured endothelial cells. Fenofibrate also attenuated overexpression of intercellular adhesion molecule-1, monocyte chemoattractant protein-1, and vascular endothelial growth factor (VEGF) and blocked activation of hypoxia-inducible factor-1 and nuclear factor-κB in the retinas of OIR and diabetic models. Fenofibrate's beneficial effects were blocked by a specific PPARα antagonist. Furthermore, Pparα knockout abolished the fenofibrate-induced downregulation of VEGF and reduction of retinal vascular leakage in DR models. These results demonstrate therapeutic effects of fenofibrate on DR in type 1 diabetes and support the existence of the drug target in ocular tissues and via a PPARα-dependent mechanism.
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Affiliation(s)
- Ying Chen
- Department of Physiology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
- Harold Hamm Diabetes Center, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Yang Hu
- Department of Physiology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
- Harold Hamm Diabetes Center, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Mingkai Lin
- Department of Physiology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
- Harold Hamm Diabetes Center, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
- Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Alicia J. Jenkins
- Harold Hamm Diabetes Center, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
- Department of Medicine, The University of Melbourne, Melbourne, Australia
| | - Anthony C. Keech
- National Health and Medical Research Council Clinical Trials Centre, University of Sydney, Sydney, Australia
| | - Robert Mott
- Department of Physiology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Timothy J. Lyons
- Harold Hamm Diabetes Center, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Jian-xing Ma
- Department of Physiology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
- Harold Hamm Diabetes Center, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
- Corresponding author: Jian-xing Ma,
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66
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Liu Y, Maxwell S, Feng T, Zhu X, Elston RC, Koyutürk M, Chance MR. Gene, pathway and network frameworks to identify epistatic interactions of single nucleotide polymorphisms derived from GWAS data. BMC SYSTEMS BIOLOGY 2012; 6 Suppl 3:S15. [PMID: 23281810 PMCID: PMC3524014 DOI: 10.1186/1752-0509-6-s3-s15] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Background Interactions among genomic loci (also known as epistasis) have been suggested as one of the potential sources of missing heritability in single locus analysis of genome-wide association studies (GWAS). The computational burden of searching for interactions is compounded by the extremely low threshold for identifying significant p-values due to multiple hypothesis testing corrections. Utilizing prior biological knowledge to restrict the set of candidate SNP pairs to be tested can alleviate this problem, but systematic studies that investigate the relative merits of integrating different biological frameworks and GWAS data have not been conducted. Results We developed four biologically based frameworks to identify pairwise interactions among candidate SNP pairs as follows: (1) for each human protein-coding gene, a set of SNPs associated with that gene was constructed providing a gene-based interaction model, (2) for each known biological pathway, a set of SNPs associated with the genes in the pathway was constructed providing a pathway-based interaction model, (3) a set of SNPs associated with genes in a disease-related subnetwork provides a network-based interaction model, and (4) a framework is based on the function of SNPs. The last approach uses expression SNPs (eSNPs or eQTLs), which are SNPs or loci that have defined effects on the abundance of transcripts of other genes. We constructed pairs of eSNPs and SNPs located in the target genes whose expression is regulated by eSNPs. For all four frameworks the SNP sets were exhaustively tested for pairwise interactions within the sets using a traditional logistic regression model after excluding genes that were previously identified to associate with the trait. Using previously published GWAS data for type 2 diabetes (T2D) and the biologically based pair-wise interaction modeling, we identify twelve genes not seen in the previous single locus analysis. Conclusion We present four approaches to detect interactions associated with complex diseases. The results show our approaches outperform the traditional single locus approaches in detecting genes that previously did not reach significance; the results also provide novel drug targets and biomarkers relevant to the underlying mechanisms of disease.
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Affiliation(s)
- Yu Liu
- Center for Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, OH, USA
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67
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Mahali SK, Manna SK. Beta-D-glucoside protects against advanced glycation end products (AGEs)-mediated diabetic responses by suppressing ERK and inducing PPAR gamma DNA binding. Biochem Pharmacol 2012; 84:1681-90. [PMID: 23058985 DOI: 10.1016/j.bcp.2012.09.033] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 09/25/2012] [Accepted: 09/26/2012] [Indexed: 01/28/2023]
Abstract
Accumulation of advanced glycation end products (AGEs), due to excessive amounts of 3- or 4-carbon sugars derived from glucose; cause multiple consequences in diabetic patients and older persons. The transcription factor, peroxisome proliferator-activated receptor gamma (PPARγ), is down regulated in the diabetic condition. Drugs targeting PPARγ were developed for diabetes therapy. We found that AGE inhibited PPARγ activity in different cell types induced by PPARγ activators, like troglitazone, rosiglitazone, oleamide, and anandamide. AGE induced translocation of PPARγ from nucleus to cytoplasm, increased on activation of ERK in cells. Antioxidants that inhibit AGE-induced NF-κB activation by preventing ROI generation were unable to protect AGE-mediated decrease in PPARγ activity. Only mangiferin, a β-D-glucoside, prevented AGE-mediated decrease in PPARγ activity and inhibited phosphorylation of ERK and cytoplasmic translocation of PPARγ. Mangiferin interacts with PPARγ and enhanced its DNA binding activity as predicted by in silico and shown by in vitro DNA-binding activity. Overall, the data suggest that (i) mangiferin inhibited AGE-induced ERK activation thereby inhibited PPARγ phosphorylation and cytoplasmic translocation; (ii) mangiferin interacts with PPARγ and enhances its DNA-binding ability. With these dual effects, mangiferin can be a likely candidate for developing therapeutic drug against diabetes.
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Affiliation(s)
- Sidhartha K Mahali
- Laboratory of Immunology, Centre for DNA Fingerprinting & Diagnostics, Nampally, Hyderabad 500001, India
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68
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Castillo-Quan JI. From white to brown fat through the PGC-1α-dependent myokine irisin: implications for diabetes and obesity. Dis Model Mech 2012; 5:293-5. [PMID: 22566556 PMCID: PMC3339822 DOI: 10.1242/dmm.009894] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Affiliation(s)
- Jorge Iván Castillo-Quan
- Institute of Healthy Ageing and Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London, WC1E 6BT, UK.
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Chakraborty S, Kaur S, Guha S, Batra SK. The multifaceted roles of neutrophil gelatinase associated lipocalin (NGAL) in inflammation and cancer. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1826:129-69. [PMID: 22513004 PMCID: PMC3362670 DOI: 10.1016/j.bbcan.2012.03.008] [Citation(s) in RCA: 280] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 03/06/2012] [Accepted: 03/08/2012] [Indexed: 02/06/2023]
Abstract
Neutrophil gelatinase associated lipocalin (NGAL), also known as oncogene 24p3, uterocalin, siderocalin or lipocalin 2, is a 24kDa secreted glycoprotein originally purified from a culture of mouse kidney cells infected with simian virus 40 (SV-40). Subsequent investigations have revealed that it is a member of the lipocalin family of proteins that transport small, hydrophobic ligands. Since then, NGAL expression has been reported in several normal tissues where it serves to provide protection against bacterial infection and modulate oxidative stress. Its expression is also dysregulated in several benign and malignant diseases. Its small size, secreted nature and relative stability have led to it being investigated as a diagnostic and prognostic biomarker in numerous diseases including inflammation and cancer. Functional studies, conducted primarily on lipocalin 2 (Lcn2), the mouse homologue of human NGAL have revealed that Lcn2 has a strong affinity for iron complexed to both bacterial siderophores (iron-binding proteins) and certain human proteins like norepinephrine. By sequestering iron-laden siderophores, Lcn2 deprives bacteria of a vital nutrient and thus inhibits their growth (bacteriostatic effect). In malignant cells, its proposed functions range from inhibiting apoptosis (in thyroid cancer cells), invasion and angiogenesis (in pancreatic cancer) to increasing proliferation and metastasis (in breast and colon cancer). Ectopic expression of Lcn2 also promotes BCR-ABL induced chronic myelogenous leukemia in murine models. By transporting iron into and out of the cell, NGAL also regulates iron responsive genes. Further, it stabilizes the proteolytic enzyme matrix metalloprotease-9 (MMP-9) by forming a complex with it, and thereby prevents its autodegradation. The factors regulating NGAL expression are numerous and range from pro-inflammatory cytokines like interleukins, tumor necrosis factor-α and interferons to vitamins like retinoic acid. The purpose of this review article is to examine the expression, structure, regulation and biological role of NGAL and critically assess its potential as a novel diagnostic and prognostic marker in both benign and malignant human diseases.
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Affiliation(s)
- Subhankar Chakraborty
- Department of Biochemistry and Molecular Biology, The UT MD Anderson Cancer Center, Houston, Texas
| | - Sukhwinder Kaur
- Department of Biochemistry and Molecular Biology, The UT MD Anderson Cancer Center, Houston, Texas
| | - Sushovan Guha
- Departments of Gastroenterology, Hepatology, and Nutrition, The UT MD Anderson Cancer Center, Houston, Texas
| | - Surinder K. Batra
- Department of Biochemistry and Molecular Biology, The UT MD Anderson Cancer Center, Houston, Texas
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE
- Eppley Institute for Cancer Research, Department of Surgery, University of Nebraska Medical Center, Omaha, NE
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Sasongko MB, Wong TY, Nguyen TT, Kawasaki R, Jenkins AJ, Shaw J, Robinson C, Wang JJ. Serum apolipoproteins are associated with systemic and retinal microvascular function in people with diabetes. Diabetes 2012; 61:1785-92. [PMID: 22511207 PMCID: PMC3379684 DOI: 10.2337/db11-1272] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Serum apolipoprotein (apo)AI and -B have been shown to be associated with diabetic retinopathy, but the underlying mechanisms are unclear. We investigated whether apoAI and apoB levels are associated with measures of systemic and retinal microvascular function in patients with diabetes. We recruited 224 diabetic patients (85 type 1 and 139 type 2) and assessed serum lipids and lipoproteins from fasting blood, skin responses to sodium nitroprusside (endothelium independent) and acetylcholine (ACh) (endothelium dependent) iontophoresis, flicker-light-induced retinal vasodilatation, and retinal vascular tortuosity. After adjustment for age and sex, every SD increase in apoAI level was associated with ACh-induced skin perfusion (mean change 1.27%; P < 0.001 for apoAI) and flicker-light retinal arteriolar vasodilatation (0.33%; P = 0.003) and was associated inversely with arteriolar tortuosity (-2.83 × 10(-5); P = 0.044). Each SD increase in apoB was associated with arteriolar tortuosity only (1.75 × 10(-5); P = 0.050). These associations, except for apoB, remained in multivariate models. Serum apoAI was associated with increased vasomotor responsiveness to ACh and flickering light and inversely related to retinal vessel tortuosity--a characteristic that has both structural and functional dimensions. These findings provide additional insights into the potential mechanisms of apos in the pathogenesis of diabetic retinopathy and other diabetic microvascular complications.
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Affiliation(s)
- Muhammad Bayu Sasongko
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, Melbourne, Australia
- Department of Ophthalmology, Faculty of Medicine, Gadjah Mada University, Yogyakarta, Indonesia
| | - Tien Y. Wong
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, Melbourne, Australia
- Singapore Eye Research Institute, National University of Singapore, Singapore, Singapore
| | - Thanh T. Nguyen
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, Melbourne, Australia
| | - Ryo Kawasaki
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, Melbourne, Australia
| | - Alicia J. Jenkins
- Department of Medicine, University of Melbourne, Melbourne, Australia
| | - Jonathan Shaw
- Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - Carol Robinson
- Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - Jie Jin Wang
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, Melbourne, Australia
- Centre for Vision Research, University of Sydney, Sydney, Australia
- Corresponding author: Jie Jin Wang,
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Wang C, Pan Y, Zhang QY, Wang FM, Kong LD. Quercetin and allopurinol ameliorate kidney injury in STZ-treated rats with regulation of renal NLRP3 inflammasome activation and lipid accumulation. PLoS One 2012; 7:e38285. [PMID: 22701621 PMCID: PMC3372527 DOI: 10.1371/journal.pone.0038285] [Citation(s) in RCA: 157] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 05/03/2012] [Indexed: 12/22/2022] Open
Abstract
Hyperuricemia, hyperlipidemia and inflammation are associated with diabetic nephropathy. The NLRP3 inflammasome-mediated inflammation is recently recognized in the development of kidney injury. Urate and lipid are considered as danger signals in the NLRP3 inflammasome activation. Although dietary flavonoid quercetin and allopurinol alleviate hyperuricemia, dyslipidmia and inflammation, their nephroprotective effects are currently unknown. In this study, we used streptozotocin (STZ)-induced diabetic nephropathy model with hyperuricemia and dyslipidemia in rats, and found over-expression of renal inflammasome components NLRP3, apoptosis-associated speck-like protein and Caspase-1, resulting in elevation of IL-1β and IL-18, with subsequently deteriorated renal injury. These findings demonstrated the possible association between renal NLRP3 inflammasome activation and lipid accumulation to superimpose causes of nephrotoxicity in STZ-treated rats. The treatment of quercetin and allopurinol regulated renal urate transport-related proteins to reduce hyperuricemia, and lipid metabolism-related genes to alleviate kidney lipid accumulation in STZ-treated rats. Furthermore, quercetin and allopurinol were found to suppress renal NLRP3 inflammasome activation, at least partly, via their anti-hyperuricemic and anti-dyslipidemic effects, resulting in the amelioration of STZ-induced the superimposed nephrotoxicity in rats. These results may provide a basis for the prevention of diabetes-associated nephrotoxicity with urate-lowering agents such as quercetin and allopurinol.
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Affiliation(s)
- Chuang Wang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, People's Republic of China
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72
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Rodríguez-Vilarrupla A, Laviña B, García-Calderó H, Russo L, Rosado E, Roglans N, Bosch J, García-Pagán JC. PPARα activation improves endothelial dysfunction and reduces fibrosis and portal pressure in cirrhotic rats. J Hepatol 2012; 56:1033-1039. [PMID: 22245887 DOI: 10.1016/j.jhep.2011.12.008] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 12/12/2011] [Accepted: 12/14/2011] [Indexed: 12/11/2022]
Abstract
BACKGROUND & AIMS Peroxisome proliferator-activated receptor α (PPARα) is a transcription factor activated by ligands that regulates genes related to vascular tone, oxidative stress, and fibrogenesis, pathways implicated in the development of cirrhosis and portal hypertension. This study aims at evaluating the effects of PPARα activation with fenofibrate on hepatic and systemic hemodynamics, hepatic endothelial dysfunction, and hepatic fibrosis in CCl(4)-cirrhotic rats. METHODS Mean arterial pressure (MAP), portal pressure (PP), and portal blood flow (PBF) were measured in cirrhotic rats treated with oral fenofibrate (25mg/kg/day, n=10) or its vehicle (n=12) for 7 days. The liver was then perfused and dose-relaxation curves to acetylcholine (Ach) were performed. We also evaluated Sirius Red staining of liver sections, collagen-I mRNA expression, and smooth muscle actin (α-SMA) protein expression, cyclo-oxygenase-1 (COX-1) protein expression, and cGMP levels in liver homogenates, and TXB(2) production in perfusates. Nitric oxide (NO) bioavailability and eNOS activation were measured in hepatic endothelial cells (HEC) isolated from cirrhotic rat livers. RESULTS CCl(4) cirrhotic rats treated with fenofibrate had a significantly lower PP (-29%) and higher MAP than those treated with vehicle. These effects were associated with a significant reduction in hepatic fibrosis and improved vasodilatory response to acetylcholine. Moreover, a reduction in COX-1 expression and TXB(2) production in rats receiving fenofibrate and a significant increase in NO bioavailability in HEC with fenofibrate were observed. CONCLUSIONS PPARα activation markedly reduced PP and liver fibrosis and improved hepatic endothelial dysfunction in cirrhotic rats, suggesting it may represent a new therapeutic strategy for portal hypertension in cirrhosis.
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Affiliation(s)
- Aina Rodríguez-Vilarrupla
- Hepatic Hemodynamic Laboratory, Liver Unit, IMDIM, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and Ciberehd, University of Barcelona, Spain.
| | - Bàrbara Laviña
- Hepatic Hemodynamic Laboratory, Liver Unit, IMDIM, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and Ciberehd, University of Barcelona, Spain
| | - Héctor García-Calderó
- Hepatic Hemodynamic Laboratory, Liver Unit, IMDIM, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and Ciberehd, University of Barcelona, Spain
| | - Lucia Russo
- Hepatic Hemodynamic Laboratory, Liver Unit, IMDIM, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and Ciberehd, University of Barcelona, Spain
| | - Eugenio Rosado
- Hepatic Hemodynamic Laboratory, Liver Unit, IMDIM, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and Ciberehd, University of Barcelona, Spain
| | - Núria Roglans
- Pharmacology Unit, Department of Pharmacology and Therapeutic Chemistry, School of Pharmacy, University of Barcelona, Spain
| | - Jaume Bosch
- Hepatic Hemodynamic Laboratory, Liver Unit, IMDIM, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and Ciberehd, University of Barcelona, Spain
| | - Joan Carles García-Pagán
- Hepatic Hemodynamic Laboratory, Liver Unit, IMDIM, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and Ciberehd, University of Barcelona, Spain
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Friedman SL. A silent partner no longer – sinusoidal endothelial cells in liver homeostasis and disease. J Hepatol 2012; 56:1001-1002. [PMID: 22322233 DOI: 10.1016/j.jhep.2012.01.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 01/30/2012] [Indexed: 12/04/2022]
Affiliation(s)
- Scott L Friedman
- Division of Liver Diseases, Mount Sinai School of Medicine, New York, NY, USA.
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74
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Nicholls SJ, Uno K. Peroxisome proliferator-activated receptor (PPAR α/γ) agonists as a potential target to reduce cardiovascular risk in diabetes. Diab Vasc Dis Res 2012; 9:89-94. [PMID: 22407927 DOI: 10.1177/1479164112441477] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The disappointing results of glucose lowering studies have highlighted the ongoing need to develop new therapeutic strategies to reduce cardiovascular risk in patients with type 2 diabetes. The presence of a range of metabolic abnormalities in diabetic patients presents a number of potential targets for therapeutic intervention. While modulation of peroxisome proliferator activated receptors (PPARs) represents an attractive approach, the results of studies of pharmacological agonists have been variable. The findings of these studies and rationale for development of dual PPAR-α/γ agonists will be reviewed.
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Affiliation(s)
- Stephen J Nicholls
- Cleveland Clinic Coordinating Center for Clinical Research and Department of Cardiovascular Medicine, Cleveland Clinic, OH 44195, USA.
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Nebbaki SS, El Mansouri FE, Afif H, Kapoor M, Benderdour M, Duval N, Pelletier JP, Martel-Pelletier J, Fahmi H. Egr-1 contributes to IL-1-mediated down-regulation of peroxisome proliferator-activated receptor γ expression in human osteoarthritic chondrocytes. Arthritis Res Ther 2012; 14:R69. [PMID: 22455954 PMCID: PMC3446440 DOI: 10.1186/ar3788] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 02/17/2012] [Accepted: 03/28/2012] [Indexed: 02/06/2023] Open
Abstract
INTRODUCTION Peroxisome proliferator-activated receptor (PPAR)γ has been shown to exhibit anti-inflammatory and anti-catabolic properties and to be protective in animal models of osteoarthritis (OA). We have previously shown that interleukin-1β (IL-1) down-regulates PPARγ expression in human OA chondrocytes. However, the mechanisms underlying this effect have not been well characterized. The PPARγ promoter harbors an overlapping Egr-1/specificity protein 1 (Sp1) binding site. In this study, our objective was to define the roles of Egr-1 and Sp1 in IL-1-mediated down-regulation of PPARγ expression. METHODS Chondrocytes were stimulated with IL-1 and the expression levels of Egr-1 and Sp1 mRNAs and proteins were evaluated using real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting, respectively. The role of de novo protein synthesis was evaluated using the protein synthesis inhibitor cycloheximide (CHX). The recruitment of Sp1 and Egr-1 to the PPARγ promoter was evaluated using chromatin immunoprecipitation (ChIP) assays. The PPARγ promoter activity was analyzed in transient transfection experiments. The roles of Egr-1 and Sp1 were further evaluated using small interfering RNA (siRNA) approaches. The level of Egr-1 in cartilage was determined using immunohistochemistry. RESULTS Down-regulation of PPARγ expression by IL-1 requires de novo protein synthesis and was concomitant with the induction of the transcription factor Egr-1. Treatment with IL-1 induced Egr-1 recruitment and reduced Sp1 occupancy at the PPARγ promoter. Overexpression of Egr-1 potentiated, whereas overexpression of Sp1 alleviated, the suppressive effect of IL-1 on the PPARγ promoter, suggesting that Egr-1 may mediate the suppressive effect of IL-1. Consistently, Egr-1 silencing prevented IL-1-mediated down-regulation of PPARγ expression. We also showed that the level of Egr-1 expression was elevated in OA cartilage compared to normal cartilage. CONCLUSIONS Our results indicate that induction and recruitment of Egr-1 contributed to the suppressive effect of IL-1 on PPARγ expression. They also suggest that modulation of Egr-1 levels in the joint may have therapeutic potential in OA.
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Affiliation(s)
- Sarah-Salwa Nebbaki
- Osteoarthritis Research Unit, Research Centre of the University of Montreal Hospital Center (CR-CHUM), Notre-Dame Hospital, 1560 Sherbrooke Street East, J,A, DeSève Pavillion, Y-2628, and Department of Medicine, University of Montreal, Montreal, QC H2L 4M1, Canada
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Goto T, Kim YI, Funakoshi K, Teraminami A, Uemura T, Hirai S, Lee JY, Makishima M, Nakata R, Inoue H, Senju H, Matsunaga M, Horio F, Takahashi N, Kawada T. Farnesol, an isoprenoid, improves metabolic abnormalities in mice via both PPARα-dependent and -independent pathways. Am J Physiol Endocrinol Metab 2011; 301:E1022-32. [PMID: 21862726 DOI: 10.1152/ajpendo.00061.2011] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Peroxisome proliferator-activated receptors (PPARs) control energy homeostasis. In this study, we showed that farnesol, a naturally occurring ligand of PPARs, could ameliorate metabolic diseases. Obese KK-Ay mice fed a high-fat diet (HFD) containing 0.5% farnesol showed significantly decreased serum glucose level, glucosuria incidence, and hepatic triglyceride contents. Farnesol-containing HFD upregulated the mRNA expressions of PPARα target genes involved in fatty acid oxidation in the liver. On the other hand, farnesol was not effective in upregulating the mRNA expressions of PPARγ target genes in white adipose tissues. Experiments using PPARα-deficient [(-/-)] mice revealed that the upregulation of fatty acid oxidation-related genes required PPARα function, but the suppression of hepatic triglyceride accumulation was partially PPARα-dependent. In hepatocytes isolated from the wild-type and PPARα (-/-) mice, farnesol suppressed triglyceride synthesis. In luciferase assay, farnesol activated both PPARα and the farnesoid X receptor (FXR) at similar concentrations. Moreover, farnesol increased the mRNA expression level of a small heterodimer partner known as one of the FXR target genes and decreased those of sterol regulatory element-binding protein-1c and fatty acid synthase in both the wild-type and PPARα (-/-) hepatocytes. These findings suggest that farnesol could improve metabolic abnormalities in mice via both PPARα-dependent and -independent pathways and that the activation of FXR by farnesol might contribute partially to the PPARα-independent hepatic triglyceride content-lowering effect. To our knowledge, this is the first study on the effect of the dual activators of PPARα and FXR on obesity-induced metabolic disorders.
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Affiliation(s)
- Tsuyoshi Goto
- Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Japan
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PPAR-α transcriptional activity is required to combat doxorubicin-induced podocyte injury in mice. Kidney Int 2011; 79:1274-6. [PMID: 21625258 DOI: 10.1038/ki.2011.36] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Immunosuppressants and inhibitors of the renin angiotensin system are major reagents to treat nephrotic syndrome but their clinical effects are not necessarily satisfactory. Injection of doxorubicin in several strains of mice causes nephrotic syndrome-like disorder. Zhou et al. report that PPAR-α expression is downregulated in murine doxorubicin nephropathy and a PPAR-α agonist, fenofibrate, partially ameliorates the disorder induced likely through stabilization of nephrin expression and suppression of apoptosis in podocytes, providing a new preventive strategy.
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Adeghate E, Adem A, Hasan MY, Tekes K, Kalasz H. Medicinal Chemistry and Actions of Dual and Pan PPAR Modulators. THE OPEN MEDICINAL CHEMISTRY JOURNAL 2011; 5:93-8. [PMID: 21966330 PMCID: PMC3174518 DOI: 10.2174/1874104501105010093] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 02/25/2011] [Accepted: 03/11/2011] [Indexed: 11/22/2022]
Abstract
Peroxisome proliferator-activated receptor (PPAR) agonists are used as adjunct therapy in the treatment of diabetes mellitus. Fibrates, including fenofibrate, gemfibrozil, benzafibrate, ciprofibrate, and clofibrate act on PPAR alpha to reduce the level of hypertriglyceridemia. However, agonists (ligands) of PPAR-beta/delta receptors, such as tesaglitazar, muraglitazar, ragaglitazar, imiglitazar, aleglitazar, alter the body's energy substrate preference from glucose to lipids and hence contribute to the reduction of blood glucose level. Glitazones or thiazolidinediones on the other hand, bind to PPAR-gamma receptors located in the nuclei of cells. Activation of PPAR-gamma receptors leads to a decrease in insulin resistance and modification of adipocyte metabolism. They reduce hyperlipidaemia by increasing the level of ATP-binding cassette A1, which modifies extra-hepatic cholesterol into HDL. Dual or pan PPAR ligands stimulate two or more isoforms of PPAR and thereby reduce insulin resistance and prevent short- and long-term complications of diabetes including micro-and macroangiopathy and atherosclerosis, which are caused by deposition of cholesterol. This review examines the chemical structure, actions, side effects and future prospects of dual and pan PPAR agonists.
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Affiliation(s)
- Ernest Adeghate
- Department of Anatomy, Faculty of Medicine and Health Science, United Arab Emirates, University Al Ain, United Arab Emirates
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Abstract
With a developing worldwide epidemic of diabetes mellitus, the renal complications associated with diabetes have become a serious health concern. Primary therapy for treating diabetic nephropathy is a multifactorial process. Peroxisome proliferator-activated receptor alpha (PPARα) agonists have been used primarily in clinical practice for the treatment of dyslipidemia and insulin resistance. Given that PPARα expression and regulation of metabolic pathways are involved in oxidative stress, inflammation, blood pressure regulation, and the renin-angiotensin aldosterone system, PPARα likely influences the development and pathogenesis of diabetic nephropathy via indirect effects on glucose and lipid homeostasis and also by direct action on the kidneys. These findings suggest that PPARα may become an important therapeutic target for treating diabetic renal complications.
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Affiliation(s)
- Sungjin Chung
- Division of Nephrology, Department of Internal Medicine, The Catholic University of Korea College of Medicine, Seoul, Korea
| | - Cheol Whee Park
- Division of Nephrology, Department of Internal Medicine, The Catholic University of Korea College of Medicine, Seoul, Korea
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Al-Najjar BO, Wahab HA, Tengku Muhammad TS, Shu-Chien AC, Ahmad Noruddin NA, Taha MO. Discovery of new nanomolar peroxisome proliferator-activated receptor γ activators via elaborate ligand-based modeling. Eur J Med Chem 2011; 46:2513-29. [PMID: 21482446 DOI: 10.1016/j.ejmech.2011.03.040] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Revised: 03/12/2011] [Accepted: 03/16/2011] [Indexed: 11/30/2022]
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Abstract
The approach of all ophthalmologists, diabetologists and general practitioners seeing patients with diabetic retinopathy should be that good control of blood glucose, blood pressure and plasma lipids are all essential components of modern medical management. The more recent data on the use of fenofibrate in the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) and The Action to Control Cardiovascular Risk in Diabetes (ACCORD) Eye studies is reviewed. In FIELD, fenofibrate (200 mg/day) reduced the requirements for laser therapy and prevented disease progression in patients with pre-existing diabetic retinopathy. In ACCORD Eye, fenofibrate (160 mg daily) with simvastatin resulted in a 40% reduction in the odds of retinopathy progressing over 4 years, compared with simvastatin alone. This occurred with an increase in HDL-cholesterol and a decrease in the serum triglyceride level in the fenofibrate group, as compared with the placebo group, and was independent of glycaemic control. We believe fenofibrate is effective in preventing progression of established diabetic retinopathy in type 2 diabetes and should be considered for patients with pre-proliferative diabetic retinopathy and/or diabetic maculopathy, particularly in those with macular oedema requiring laser.
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Hu C, Cong XD, Dai DZ, Zhang Y, Zhang GL, Dai Y. Argirein alleviates diabetic nephropathy through attenuating NADPH oxidase, Cx43, and PERK in renal tissue. Naunyn Schmiedebergs Arch Pharmacol 2011; 383:309-19. [DOI: 10.1007/s00210-010-0593-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Accepted: 12/17/2010] [Indexed: 12/21/2022]
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