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Weinstein N, Carlsen J, Schulz S, Stapleton T, Henriksen HH, Travnik E, Johansson PI. A Lifelike guided journey through the pathophysiology of pulmonary hypertension-from measured metabolites to the mechanism of action of drugs. Front Cardiovasc Med 2024; 11:1341145. [PMID: 38845688 PMCID: PMC11153715 DOI: 10.3389/fcvm.2024.1341145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Accepted: 04/12/2024] [Indexed: 06/09/2024] Open
Abstract
Introduction Pulmonary hypertension (PH) is a pathological condition that affects approximately 1% of the population. The prognosis for many patients is poor, even after treatment. Our knowledge about the pathophysiological mechanisms that cause or are involved in the progression of PH is incomplete. Additionally, the mechanism of action of many drugs used to treat pulmonary hypertension, including sotatercept, requires elucidation. Methods Using our graph-powered knowledge mining software Lifelike in combination with a very small patient metabolite data set, we demonstrate how we derive detailed mechanistic hypotheses on the mechanisms of PH pathophysiology and clinical drugs. Results In PH patients, the concentration of hypoxanthine, 12(S)-HETE, glutamic acid, and sphingosine 1 phosphate is significantly higher, while the concentration of L-arginine and L-histidine is lower than in healthy controls. Using the graph-based data analysis, gene ontology, and semantic association capabilities of Lifelike, led us to connect the differentially expressed metabolites with G-protein signaling and SRC. Then, we associated SRC with IL6 signaling. Subsequently, we found associations that connect SRC, and IL6 to activin and BMP signaling. Lastly, we analyzed the mechanisms of action of several existing and novel pharmacological treatments for PH. Lifelike elucidated the interplay between G-protein, IL6, activin, and BMP signaling. Those pathways regulate hallmark pathophysiological processes of PH, including vasoconstriction, endothelial barrier function, cell proliferation, and apoptosis. Discussion The results highlight the importance of SRC, ERK1, AKT, and MLC activity in PH. The molecular pathways affected by existing and novel treatments for PH also converge on these molecules. Importantly, sotatercept affects SRC, ERK1, AKT, and MLC simultaneously. The present study shows the power of mining knowledge graphs using Lifelike's diverse set of data analytics functionalities for developing knowledge-driven hypotheses on PH pathophysiological and drug mechanisms and their interactions. We believe that Lifelike and our presented approach will be valuable for future mechanistic studies of PH, other diseases, and drugs.
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Affiliation(s)
- Nathan Weinstein
- CAG Center for Endotheliomics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Jørn Carlsen
- CAG Center for Endotheliomics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Department of Cardiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Sebastian Schulz
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Timothy Stapleton
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Hanne H. Henriksen
- CAG Center for Endotheliomics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Immunology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Evelyn Travnik
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Pär Ingemar Johansson
- CAG Center for Endotheliomics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Immunology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
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Nuclear corepressor SMRT acts as a strong regulator of both β-oxidation and suppressor of fibrosis in the differentiation process of mouse skeletal muscle cells. PLoS One 2022; 17:e0277830. [PMID: 36454860 PMCID: PMC9714868 DOI: 10.1371/journal.pone.0277830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 11/03/2022] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Silencing Mediator of Retinoid and Thyroid hormone receptors (SMRT; NCoR2) is a transcriptional corepressor (CoR) which has been recognized as an important player in the regulation of hepatic lipogenesis and in somatic development in mouse embryo. SMRT protein is also widely expressed in mouse connective tissues, for example adipocytes and muscle. We recently reported that mice with global deletion of SMRT develop significant obesity and muscle wasting which are independent from thyroid hormone (TH) signaling and thermogenesis. However, the tissue specific role of SMRT in skeletal muscle is still not clear. METHODS To clarify role of SMRT in muscle differentiation, we made myogenic C2C12 clones which lack SMRT protein (C2C12-SKO) by using CRISPR-Cas9. Wild-type C2C12 (C2C12-WT) and C2C12-SKO cells were cultured in differentiation medium, and the resulting gene and protein profiles were compared between the two cell lines both before and after differentiation. We also analyzed muscle tissues which were dissected from whole body SMRT knockout (KO) mice and their controls. RESULTS We found significant up-regulation of muscle specific β-oxidation markers; Peroxisome proliferator-activated receptor δ (PPARδ) and PPARγ coactivator-1α (PGC-1α) in the C2C12-SKO cells, suggesting that the cells had a similar gene profile to what is found in exercised rodent skeletal muscle. On the other hand, confocal microscopic analysis showed the significant loss of myotubes in C2C12-SKO cells similar to the morphology found in immature myoblasts. Proteomics analysis also confirmed that the C2C12-SKO cells had higher expression of markers of fibrosis (ex. Collagen1A1; COL1A1 and Fibroblast growth factor-2; FGF-2), indicating the up-regulation of Transforming growth factor-β (TGF-β) receptor signaling. Consistent with this, treatment with a specific TGF-β receptor inhibitor ameliorated both the defects in myotube differentiation and fibrosis. CONCLUSION Taken together, we demonstrate that SMRT functions as a pivotal transcriptional mediator for both β-oxidation and the prevention for the fibrosis via TGF-β receptor signaling in the differentiation of C2C12 myoblasts. In contrast to the results from C2C12 cells, SMRT does not appear to play a role in adult skeletal muscle of whole body SMRT KO mice. Thus, SMRT plays a significant role in the differentiation of myoblasts.
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Ahn J, Son HJ, Seo HD, Ha TY, Ahn J, Lee H, Shin SH, Jung CH, Jang YJ. γ-Oryzanol Improves Exercise Endurance and Muscle Strength by Upregulating PPARδ and ERRγ Activity in Aged Mice. Mol Nutr Food Res 2021; 65:e2000652. [PMID: 33932312 DOI: 10.1002/mnfr.202000652] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 04/05/2021] [Indexed: 12/24/2022]
Abstract
SCOPE γ-Oryzanol, a well-known antioxidant, has been used by body builders and athletes to boost strength and increase muscle gain, without major side effects. However, the effect of γ-Oryzanol on sarcopenia and the underlying molecular mechanism is poorly understood. RESULTS Aged mice fed with the γ-Oryzanol diet do not show significant changes in muscle weight, but show increased running endurance as well as improved grip strength. The expression and activity of PPARδ and ERRγ are increased in skeletal muscle of γ-Oryzanol supplemented mice. γ-Oryzanol upregulates oxidative muscle fibers by MEF2 transcription factor, and PGC-1α and ERRα expressions. Fatty acid oxidation related genes and mitochondria biogenesis are upregulated by γ-Oryzanol. In addition, γ-Oryzanol inhibits TGF-β-Smad-NADPH oxidase 4 pathway and inflammatory cytokines such as TNF-α, IL-1β, IL-6, and p65 NF-κB subunit, which cause skeletal muscle weakness. Collectively, γ-Oryzanol attenuates muscle weakness pathway and increases oxidative capacity by increasing PPARδ and ERRγ activity, which contributes to enhance strength and improve oxidative capacity in muscles, consequently enhancing exercise capacity in aged mice. Particularly, γ-Oryzanol directly binds to PPARδ. CONCLUSIONS These are the first findings showing that γ-Oryzanol enhances skeletal muscle function in aged mice by regulating PPARδ and ERRγ activity without muscle gain.
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Affiliation(s)
- Jisong Ahn
- Natural Materials and Metabolism Research Group, Korea Food Research Institute, Wanju, 55365, Republic of Korea
- Department of Food Science and Technology, Chonbuk National University, Jeonju, 54896, Republic of Korea
| | - Hyo Jeong Son
- Natural Materials and Metabolism Research Group, Korea Food Research Institute, Wanju, 55365, Republic of Korea
| | - Hyo Deok Seo
- Natural Materials and Metabolism Research Group, Korea Food Research Institute, Wanju, 55365, Republic of Korea
| | - Tae Youl Ha
- Natural Materials and Metabolism Research Group, Korea Food Research Institute, Wanju, 55365, Republic of Korea
- Division of Food Biotechnology, University of Science and Technology, Daejeon, 34113, Republic of Korea
| | - Jiyun Ahn
- Natural Materials and Metabolism Research Group, Korea Food Research Institute, Wanju, 55365, Republic of Korea
- Division of Food Biotechnology, University of Science and Technology, Daejeon, 34113, Republic of Korea
| | - Hyunjung Lee
- Natural Materials and Metabolism Research Group, Korea Food Research Institute, Wanju, 55365, Republic of Korea
| | - Seung Ho Shin
- Department of Food and Nutrition, Gyeongsang National University, Jinju, 52828, Republic of Korea
- The Hormel Institute, University of Minnesota, Austin, MN, 55912, USA
| | - Chang Hwa Jung
- Natural Materials and Metabolism Research Group, Korea Food Research Institute, Wanju, 55365, Republic of Korea
- Division of Food Biotechnology, University of Science and Technology, Daejeon, 34113, Republic of Korea
| | - Young Jin Jang
- Natural Materials and Metabolism Research Group, Korea Food Research Institute, Wanju, 55365, Republic of Korea
- Major of Food Science & Technology, Seoul Women's University, Seoul, 01797, Republic of Korea
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Bolfer L, Estrada AH, Larkin C, Conlon TJ, Lourenco F, Taggart K, Suzuki-Hatano S, Pacak CA. Functional Consequences of PDK4 Deficiency in Doberman Pinscher Fibroblasts. Sci Rep 2020; 10:3930. [PMID: 32127618 PMCID: PMC7054397 DOI: 10.1038/s41598-020-60879-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 02/17/2020] [Indexed: 12/30/2022] Open
Abstract
A splice site mutation in the canine pyruvate dehydrogenase kinase 4 (PDK4) gene has been shown to be associated with the development of dilated cardiomyopathy (DCM) in Doberman Pinchers (DPs). Subsequent studies have successfully demonstrated the use of dermal fibroblasts isolated from DPs as models for PDK4 deficiency and have shown activation of the intrinsic (mitochondrial mediated) apoptosis pathway in these cells under starvation conditions. For this study, we sought to further explore the functional consequences of PDK4 deficiency in DP fibroblasts representing PDK4wt/wt, PDK4wt/del, and PDK4del/del genotypes. Our results show that starvation conditions cause increased perinuclear localization of mitochondria and decreased cell proliferation, altered expression levels of pyruvate dehydrogenase phosphatase (PDP) and pyruvate dehydrogenase (PDH), dramatically increased PDH activity, and an impaired response to mitochondrial stress in affected cells. In sum, these results show the broad impact of PDK4 deficiency and reveal mechanistic pathways used by these cells in an attempt to compensate for the condition. Our data help to elucidate the mechanisms at play in this extremely prevalent DP disorder and provide further support demonstrating the general importance of metabolic flexibility in cell health.
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Affiliation(s)
- Luiz Bolfer
- Department of Small Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville, FL, 32610, USA
| | - Amara H Estrada
- Department of Small Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville, FL, 32610, USA
| | - Chelsea Larkin
- Department of Small Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville, FL, 32610, USA.,Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL, 32610, USA
| | - Thomas J Conlon
- CR Scientific and Compliance Consulting, LLC, Gainesville, FL, 32608, USA
| | - Francisco Lourenco
- Department of Small Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville, FL, 32610, USA
| | - Kathryn Taggart
- Department of Small Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville, FL, 32610, USA
| | - Silveli Suzuki-Hatano
- Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL, 32610, USA
| | - Christina A Pacak
- Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL, 32610, USA. .,Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, FL, 32610, USA.
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Liu C, Lim ST, Teo MHY, Tan MSY, Kulkarni MD, Qiu B, Li A, Lal S, Dos Remedios CG, Tan NS, Wahli W, Ferenczi MA, Song W, Hong W, Wang X. Collaborative Regulation of LRG1 by TGF-β1 and PPAR-β/δ Modulates Chronic Pressure Overload-Induced Cardiac Fibrosis. Circ Heart Fail 2019; 12:e005962. [PMID: 31830829 DOI: 10.1161/circheartfailure.119.005962] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Despite its established significance in fibrotic cardiac remodeling, clinical benefits of global inhibition of TGF (transforming growth factor)-β1 signaling remain controversial. LRG1 (leucine-rich-α2 glycoprotein 1) is known to regulate endothelial TGFβ signaling. This study evaluated the role of LRG1 in cardiac fibrosis and its transcriptional regulatory network in cardiac fibroblasts. METHODS Pressure overload-induced heart failure was established by transverse aortic constriction. Western blot, quantitative reverse transcription polymerase chain reaction, immunofluorescence, and immunohistochemistry were used to evaluate the expression level and pattern of interested targets or pathology during fibrotic cardiac remodeling. Cardiac function was assessed by pressure-volume loop analysis. RESULTS LRG1 expression was significantly suppressed in left ventricle of mice with transverse aortic constriction-induced fibrotic cardiac remodeling (mean difference, -0.00085 [95% CI, -0.0013 to -0.00043]; P=0.005) and of patients with end-stage ischemic-dilated cardiomyopathy (mean difference, 0.13 [95% CI, 0.012-0.25]; P=0.032). More profound cardiac fibrosis (mean difference, -0.014% [95% CI, -0.029% to -0.00012%]; P=0.048 for interstitial fibrosis; mean difference, -1.3 [95% CI, -2.5 to -0.2]; P=0.016 for perivascular fibrosis), worse cardiac dysfunction (mean difference, -2.5 ms [95% CI, -4.5 to -0.4 ms]; P=0.016 for Tau-g; mean difference, 13% [95% CI, 2%-24%]; P=0.016 for ejection fraction), and hyperactive TGFβ signaling in transverse aortic constriction-operated Lrg1-deficient mice (mean difference, -0.27 [95% CI, -0.47 to -0.07]; P<0.001), which could be reversed by cardiac-specific Lrg1 delivery mediated by adeno-associated virus 9. Mechanistically, LRG1 inhibits cardiac fibroblast activation by competing with TGFβ1 for receptor binding, while PPAR (peroxisome proliferator-activated receptor)-β/δ and TGFβ1 collaboratively regulate LRG1 expression via SMRT (silencing mediator for retinoid and thyroid hormone receptor). We further demonstrated functional interactions between LRG1 and PPARβ/δ in cardiac fibroblast activation. CONCLUSIONS Our results established a highly complex molecular network involving LRG1, TGFβ1, PPARβ/δ, and SMRT in regulating cardiac fibroblast activation and cardiac fibrosis. Targeting LRG1 or PPARβ/δ represents a promising strategy to control pathological cardiac remodeling in response to chronic pressure overload.
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Affiliation(s)
- Chenghao Liu
- Lee Kong Chian School of Medicine (C.L., S.T.L., M.H.Y.T., M.S.Y.T., M.D.K., N.S.T., W.W., M.A.F., W.S., X.W.), Nanyang Technological University Singapore
| | - Seok Ting Lim
- Lee Kong Chian School of Medicine (C.L., S.T.L., M.H.Y.T., M.S.Y.T., M.D.K., N.S.T., W.W., M.A.F., W.S., X.W.), Nanyang Technological University Singapore
| | - Melissa Hui Yen Teo
- Lee Kong Chian School of Medicine (C.L., S.T.L., M.H.Y.T., M.S.Y.T., M.D.K., N.S.T., W.W., M.A.F., W.S., X.W.), Nanyang Technological University Singapore
| | - Michelle Si Ying Tan
- Lee Kong Chian School of Medicine (C.L., S.T.L., M.H.Y.T., M.S.Y.T., M.D.K., N.S.T., W.W., M.A.F., W.S., X.W.), Nanyang Technological University Singapore
| | - Madhura Dattatraya Kulkarni
- Lee Kong Chian School of Medicine (C.L., S.T.L., M.H.Y.T., M.S.Y.T., M.D.K., N.S.T., W.W., M.A.F., W.S., X.W.), Nanyang Technological University Singapore
| | - Beiying Qiu
- Institute of Molecular and Cell Biology, Proteos, Agency for Science, Technology and Research, Singapore (B.Q., N.S.T., W.H., X.W.)
| | - Amy Li
- Anatomy and Histology, School of Medical Sciences, Bosch Institute, University of Sydney, Australia (A.L., S.L., C.G.d.R.)
| | - Sean Lal
- Anatomy and Histology, School of Medical Sciences, Bosch Institute, University of Sydney, Australia (A.L., S.L., C.G.d.R.)
| | - Cristobal G Dos Remedios
- Anatomy and Histology, School of Medical Sciences, Bosch Institute, University of Sydney, Australia (A.L., S.L., C.G.d.R.)
| | - Nguan Soon Tan
- Lee Kong Chian School of Medicine (C.L., S.T.L., M.H.Y.T., M.S.Y.T., M.D.K., N.S.T., W.W., M.A.F., W.S., X.W.), Nanyang Technological University Singapore.,School of Biological Sciences (N.S.T.), Nanyang Technological University Singapore.,Institute of Molecular and Cell Biology, Proteos, Agency for Science, Technology and Research, Singapore (B.Q., N.S.T., W.H., X.W.).,KK Research Centre, KK Women's and Children Hospital, Singapore (N.S.T.)
| | - Walter Wahli
- Lee Kong Chian School of Medicine (C.L., S.T.L., M.H.Y.T., M.S.Y.T., M.D.K., N.S.T., W.W., M.A.F., W.S., X.W.), Nanyang Technological University Singapore.,INRA ToxAlim, UMR1331, Chemin de Tournefeuille, Toulouse, France (W.W.).,Centre for Integrative Genomics, University of Lausanne, Le Genopode, Switzerland (W.W.)
| | - Michael Alan Ferenczi
- Lee Kong Chian School of Medicine (C.L., S.T.L., M.H.Y.T., M.S.Y.T., M.D.K., N.S.T., W.W., M.A.F., W.S., X.W.), Nanyang Technological University Singapore
| | - Weihua Song
- Lee Kong Chian School of Medicine (C.L., S.T.L., M.H.Y.T., M.S.Y.T., M.D.K., N.S.T., W.W., M.A.F., W.S., X.W.), Nanyang Technological University Singapore.,National Heart Centre Singapore (W.S.)
| | - Wanjin Hong
- Institute of Molecular and Cell Biology, Proteos, Agency for Science, Technology and Research, Singapore (B.Q., N.S.T., W.H., X.W.)
| | - Xiaomeng Wang
- Lee Kong Chian School of Medicine (C.L., S.T.L., M.H.Y.T., M.S.Y.T., M.D.K., N.S.T., W.W., M.A.F., W.S., X.W.), Nanyang Technological University Singapore.,Institute of Molecular and Cell Biology, Proteos, Agency for Science, Technology and Research, Singapore (B.Q., N.S.T., W.H., X.W.).,Institute of Ophthalmology, University College London, United Kingdom (X.W.).,Singapore Eye Research Institute, The Academia, Singapore (X.W.)
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Paquette AG, Brockway HM, Price ND, Muglia LJ. Comparative transcriptomic analysis of human placentae at term and preterm delivery. Biol Reprod 2019; 98:89-101. [PMID: 29228154 PMCID: PMC5803773 DOI: 10.1093/biolre/iox163] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Accepted: 11/30/2017] [Indexed: 12/11/2022] Open
Abstract
Preterm birth affects 1 out of every 10 infants in the United States, resulting in substantial neonatal morbidity and mortality. Currently, there are few predictive markers and few treatment options to prevent preterm birth. A healthy, functioning placenta is essential to positive pregnancy outcomes. Previous studies have suggested that placental pathology may play a role in preterm birth etiology. Therefore, we tested the hypothesis that preterm placentae may exhibit unique transcriptomic signatures compared to term samples reflective of their abnormal biology leading to this adverse outcome. We aggregated publicly available placental villous microarray data to generate a preterm and term sample dataset (n = 133, 55 preterm placentae and 78 normal term placentae). We identified differentially expressed genes using the linear regression for microarray (LIMMA) package and identified perturbations in known biological networks using Differential Rank Conservation (DIRAC). We identified 129 significantly differentially expressed genes between term and preterm placenta with 96 genes upregulated and 33 genes downregulated (P-value <0.05). Significant changes in gene expression in molecular networks related to Tumor Protein 53 and phosphatidylinositol signaling were identified using DIRAC. We have aggregated a uniformly normalized transcriptomic dataset and have identified novel and established genes and pathways associated with developmental regulation of the placenta and potential preterm birth pathology. These analyses provide a community resource to integrate with other high-dimensional datasets for additional insights in normal placental development and its disruption.
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Affiliation(s)
| | - Heather M Brockway
- Division of Human Genetics, Center for Prevention of Preterm Birth, Cincinnati Children's, Hospital Medical Center, Cincinnati, Ohio, USA
| | | | - Louis J Muglia
- Division of Human Genetics, Center for Prevention of Preterm Birth, Cincinnati Children's, Hospital Medical Center, Cincinnati, Ohio, USA
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Jang YJ, Ahn J, Son HJ, Jung CH, Ahn J, Ha TY. Hydrangea serrata
Tea Enhances Running Endurance and Skeletal Muscle Mass. Mol Nutr Food Res 2019; 63:e1801149. [DOI: 10.1002/mnfr.201801149] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 04/29/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Young Jin Jang
- Research Group of Natural Materials and MetabolismKorea Food Research Institute Wanju‐gun 55365 Republic of Korea
| | - Jisong Ahn
- Research Group of Natural Materials and MetabolismKorea Food Research Institute Wanju‐gun 55365 Republic of Korea
- Department of Food Science and TechnologyChonbuk National University Jeonju‐si 54896 Republic of Korea
| | - Hyo Jeong Son
- Research Group of Natural Materials and MetabolismKorea Food Research Institute Wanju‐gun 55365 Republic of Korea
| | - Chang Hwa Jung
- Research Group of Natural Materials and MetabolismKorea Food Research Institute Wanju‐gun 55365 Republic of Korea
- Division of Food BiotechnologyUniversity of Science and Technology Daejeon 34113 Republic of Korea
| | - Jiyun Ahn
- Research Group of Natural Materials and MetabolismKorea Food Research Institute Wanju‐gun 55365 Republic of Korea
- Division of Food BiotechnologyUniversity of Science and Technology Daejeon 34113 Republic of Korea
| | - Tae Youl Ha
- Research Group of Natural Materials and MetabolismKorea Food Research Institute Wanju‐gun 55365 Republic of Korea
- Division of Food BiotechnologyUniversity of Science and Technology Daejeon 34113 Republic of Korea
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Li M, Keenan CR, Lopez-Campos G, Mangum JE, Chen Q, Prodanovic D, Xia YC, Langenbach SY, Harris T, Hofferek V, Reid GE, Stewart AG. A Non-canonical Pathway with Potential for Safer Modulation of Transforming Growth Factor-β1 in Steroid-Resistant Airway Diseases. iScience 2019; 12:232-246. [PMID: 30711747 PMCID: PMC6360516 DOI: 10.1016/j.isci.2019.01.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 03/27/2018] [Accepted: 01/15/2019] [Indexed: 12/15/2022] Open
Abstract
Impaired therapeutic responses to anti-inflammatory glucocorticoids (GC) in chronic respiratory diseases are partly attributable to interleukins and transforming growth factor β1 (TGF-β1). However, previous efforts to prevent induction of GC insensitivity by targeting established canonical and non-canonical TGF-β1 pathways have been unsuccessful. Here we elucidate a TGF-β1 signaling pathway modulating GC activity that involves LIM domain kinase 2-mediated phosphorylation of cofilin1. Severe, steroid-resistant asthmatic airway epithelium showed increased levels of immunoreactive phospho-cofilin1. Phospho-cofilin1 was implicated in the activation of phospholipase D (PLD) to generate the effector(s) (lyso)phosphatidic acid, which mimics the TGF-β1-induced GC insensitivity. TGF-β1 induction of the nuclear hormone receptor corepressor, SMRT (NCOR2), was dependent on cofilin1 and PLD activities. Depletion of SMRT prevented GC insensitivity. This pathway for GC insensitivity offers several promising drug targets that potentially enable a safer approach to the modulation of TGF-β1 in chronic inflammatory diseases than is afforded by global TGF-β1 inhibition. TGF-β1 extensively impairs GC activity Phospho-cofilin1 is a key link in TGF-β1 signaling cascade subserving GC insensitivity Phospho-cofilin1-activated phospholipase D (PLD) reduces GC activity SMRT induction downstream of PLD mediates TGF-β1 impairment of GC activity
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Affiliation(s)
- Meina Li
- Department of Pharmacology & Therapeutics, School of Biomedical Science, University of Melbourne, Parkville, VIC 3010, Australia
| | - Christine R Keenan
- Department of Pharmacology & Therapeutics, School of Biomedical Science, University of Melbourne, Parkville, VIC 3010, Australia
| | - Guillermo Lopez-Campos
- Health and Biomedical Informatics Centre, Melbourne Medical School, University of Melbourne, Parkville, VIC 3010, Australia; Centre for Experimental Medicine, Queen's University of Belfast, Belfast BT9 7BL, UK
| | - Jonathan E Mangum
- Department of Pharmacology & Therapeutics, School of Biomedical Science, University of Melbourne, Parkville, VIC 3010, Australia
| | - Qianyu Chen
- Department of Pharmacology & Therapeutics, School of Biomedical Science, University of Melbourne, Parkville, VIC 3010, Australia
| | - Danica Prodanovic
- Department of Pharmacology & Therapeutics, School of Biomedical Science, University of Melbourne, Parkville, VIC 3010, Australia
| | - Yuxiu C Xia
- Department of Pharmacology & Therapeutics, School of Biomedical Science, University of Melbourne, Parkville, VIC 3010, Australia
| | - Shenna Y Langenbach
- Department of Pharmacology & Therapeutics, School of Biomedical Science, University of Melbourne, Parkville, VIC 3010, Australia
| | - Trudi Harris
- Department of Pharmacology & Therapeutics, School of Biomedical Science, University of Melbourne, Parkville, VIC 3010, Australia
| | - Vinzenz Hofferek
- Max Plank Institute of Molecular Plant Physiology, Potsdam, Germany; School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
| | - Gavin E Reid
- School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia; Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia; Bio21 Molecular Science and Biotechnology Institute. University of Melbourne, Parkville, VIC 3010, Australia
| | - Alastair G Stewart
- Department of Pharmacology & Therapeutics, School of Biomedical Science, University of Melbourne, Parkville, VIC 3010, Australia; ARC Centre for Personalised Therapeutics Technologies, Parkville, VIC, Australia.
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Enguita M, Razquin N, Pamplona R, Quiroga J, Prieto J, Fortes P. The cirrhotic liver is depleted of docosahexaenoic acid (DHA), a key modulator of NF-κB and TGFβ pathways in hepatic stellate cells. Cell Death Dis 2019; 10:14. [PMID: 30622239 PMCID: PMC6325107 DOI: 10.1038/s41419-018-1243-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 10/15/2018] [Accepted: 10/16/2018] [Indexed: 02/06/2023]
Abstract
Liver cirrhosis results from chronic hepatic damage and is characterized by derangement of the organ architecture with increased liver fibrogenesis and defective hepatocellular function. It frequently evolves into progressive hepatic insufficiency associated with high mortality unless liver transplantation is performed. We have hypothesized that the deficiency of critical nutrients such as essential omega-3 fatty acids might play a role in the progression of liver cirrhosis. Here we evaluated by LC-MS/MS the liver content of omega-3 docosahexaenoic fatty acid (DHA) in cirrhotic patients and investigated the effect of DHA in a murine model of liver injury and in the response of hepatic stellate cells (HSCs) (the main producers of collagen in the liver) to pro-fibrogenic stimuli. We found that cirrhotic livers exhibit a marked depletion of DHA and that this alteration correlates with the progression of the disease. Administration of DHA exerts potent anti-fibrogenic effects in an acute model of liver damage. Studies with HSCs show that DHA inhibits fibrogenesis more intensely than other omega-3 fatty acids. Data from expression arrays revealed that DHA blocks TGFβ and NF-κB pathways. Mechanistically, DHA decreases late, but not early, SMAD3 nuclear accumulation and inhibits p65/RelA-S536 phosphorylation, which is required for HSC survival. Notably, DHA increases ADRP expression, leading to the formation of typical quiescence-associated perinuclear lipid droplets. In conclusion, a marked depletion of DHA is present in the liver of patients with advanced cirrhosis. DHA displays anti-fibrogenic activities on HSCs targeting NF-κB and TGFβ pathways and inducing ADPR expression and quiescence in these cells.
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Affiliation(s)
- Mónica Enguita
- Department of Gene Therapy and Hepatology, Center for Applied Medical Research (CIMA), University of Navarra (UNAV), Pamplona, Spain.,Navarra Institute for Health Research (IdiSNA), Pamplona, Spain
| | - Nerea Razquin
- Department of Gene Therapy and Hepatology, Center for Applied Medical Research (CIMA), University of Navarra (UNAV), Pamplona, Spain.,Navarra Institute for Health Research (IdiSNA), Pamplona, Spain
| | - Reinald Pamplona
- Department of Experimental Medicine, University of Lleida (IRB), Lleida, Spain
| | - Jorge Quiroga
- Navarra Institute for Health Research (IdiSNA), Pamplona, Spain.,Liver Unit, Clínica Universidad de Navarra, Pamplona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (Ciberehd), Pamplona, Spain
| | | | - Puri Fortes
- Department of Gene Therapy and Hepatology, Center for Applied Medical Research (CIMA), University of Navarra (UNAV), Pamplona, Spain. .,Navarra Institute for Health Research (IdiSNA), Pamplona, Spain.
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10
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Lucarelli P, Schilling M, Kreutz C, Vlasov A, Boehm ME, Iwamoto N, Steiert B, Lattermann S, Wäsch M, Stepath M, Matter MS, Heikenwälder M, Hoffmann K, Deharde D, Damm G, Seehofer D, Muciek M, Gretz N, Lehmann WD, Timmer J, Klingmüller U. Resolving the Combinatorial Complexity of Smad Protein Complex Formation and Its Link to Gene Expression. Cell Syst 2018; 6:75-89.e11. [DOI: 10.1016/j.cels.2017.11.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 06/23/2017] [Accepted: 11/14/2017] [Indexed: 12/11/2022]
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11
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Liu N, Cui C, Sun Y, Zhang F, Wang S, Su G, Cai X. Hydrogen peroxide promotes the expression of angiopoietin like 4 in RAW264.7 macrophages via MAPK pathways. Mol Med Rep 2017; 16:6128-6133. [PMID: 28849063 DOI: 10.3892/mmr.2017.7365] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 03/23/2017] [Indexed: 11/06/2022] Open
Abstract
Previous studies including some vivo experiments and large scale clinical trials have indicated that angiopoietin like 4 (ANGPTL4) is involved in atherosclerosis. However, the specific mechanism underlying the process remains unresolved. Similarly, cumulative evidence indicated that hydrogen peroxide (H2O2) is closely related to the occurrence and development of atherosclerosis. The current study investigated whether H2O2 treatment can affect ANGPTL4 release in macrophage cells cell viability assay, western blot analysis, ELISA and immunofluorescence. It was determined that treatment with 0.25 and 0.5 mM H2O2 resulted in a significant increase in ANGPTL4 protein expression in macrophage cells. Mitogen‑activated protein kinase (MAPK) pathways were implicated in the secretion of ANGPTL4 regulated by H2O2, and specific inhibitors of MAPK1 (also known as ERK) and p38 MAPK significantly decreased H2O2 induced ANGPTL4 protein expression. Accordingly, it was demonstrated that ANGPTL4 expression was regulated by H2O2 via ERK and p38 MAPK, but not the MAPK8 (also known as JNK) pathway. In view of the effects of H2O2 and ANGPTL4 on atherosclerosis, the influence of H2O2 on ANGPTL4 provided new insight into the mechanism of atherosclerosis.
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Affiliation(s)
- Nan Liu
- Department of Cardiovascular Medicine, Jinan Central Hospital Affiliated to Shandong University, Jinan, Shandong 250013, P.R. China
| | - Changxia Cui
- Department of Cardiovascular Medicine, Jinan Central Hospital Affiliated to Shandong University, Jinan, Shandong 250013, P.R. China
| | - Yue Sun
- Department of Cardiology, Shandong University, Cheeloo College of Medicine, Jinan, Shandong 250013, P.R. China
| | - Feng Zhang
- Department of Cardiology, Tengzhou Central People's Hospital, Tengzhou, Shandong 277500, P.R. China
| | - Shuya Wang
- Department of Cardiovascular Medicine, Jinan Central Hospital Affiliated to Shandong University, Jinan, Shandong 250013, P.R. China
| | - Guohai Su
- Department of Cardiovascular Medicine, Jinan Central Hospital Affiliated to Shandong University, Jinan, Shandong 250013, P.R. China
| | - Xiaojun Cai
- Department of Cardiovascular Medicine, Jinan Central Hospital Affiliated to Shandong University, Jinan, Shandong 250013, P.R. China
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12
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Müller R. PPARβ/δ in human cancer. Biochimie 2016; 136:90-99. [PMID: 27916645 DOI: 10.1016/j.biochi.2016.10.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 10/06/2016] [Accepted: 10/19/2016] [Indexed: 12/31/2022]
Abstract
The nuclear receptor factor peroxisome proliferator-activated receptor (PPARβ/δ) can regulate its target genes by transcriptional activation or repression through both ligand-dependent and independent mechanism as well as by interactions with other transcription factors. PPARβ/δ exerts essential regulatory functions in intermediary metabolism that have been elucidated in detail, but clearly also plays a role in inflammation, differentiation, apoptosis and other cancer-associated processes, which is, however, mechanistically only partly understood. Consistent with these functions clinical associations link the expression of PPARβ/δ and its target genes to an unfavorable outcome of several human cancers. However, the available data do not yield a clear picture of PPARβ/δ's role in cancer-associated processes and are in fact partly controversial. This article provides an overview of this research area and discusses the role of PPARβ/δ in cancer in light of the complex mechanisms of its transcriptional regulation and its potential as a druggable anti-cancer target.
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Affiliation(s)
- Rolf Müller
- Institute of Molecular Biology and Tumor Research, Center for Tumor Biology and Immunology, Philipps University, Hans-Meerwein-Str. 3, 35043 Marburg, Germany.
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13
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Possible role of TGF β1 in inflammatory pseudotumor associated with multiple neuroendocrine tumors of the small intestine. Pathol Res Pract 2015; 211:805-9. [DOI: 10.1016/j.prp.2015.06.005] [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: 12/14/2014] [Revised: 05/12/2015] [Accepted: 06/01/2015] [Indexed: 12/13/2022]
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14
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Adhikary T, Wortmann A, Schumann T, Finkernagel F, Lieber S, Roth K, Toth PM, Diederich WE, Nist A, Stiewe T, Kleinesudeik L, Reinartz S, Müller-Brüsselbach S, Müller R. The transcriptional PPARβ/δ network in human macrophages defines a unique agonist-induced activation state. Nucleic Acids Res 2015; 43:5033-51. [PMID: 25934804 PMCID: PMC4446423 DOI: 10.1093/nar/gkv331] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 04/01/2015] [Indexed: 02/06/2023] Open
Abstract
Peroxisome proliferator-activated receptor β/δ (PPARβ/δ) is a lipid ligand-inducible transcription factor with established metabolic functions, whereas its anti-inflammatory function is poorly understood. To address this issue, we determined the global PPARβ/δ-regulated signaling network in human monocyte-derived macrophages. Besides cell type-independent, canonical target genes with metabolic and immune regulatory functions we identified a large number of inflammation-associated NFκB and STAT1 target genes that are repressed by agonists. Accordingly, PPARβ/δ agonists inhibited the expression of multiple pro-inflammatory mediators and induced an anti-inflammatory, IL-4-like morphological phenotype. Surprisingly, bioinformatic analyses also identified immune stimulatory effects. Consistent with this prediction, PPARβ/δ agonists enhanced macrophage survival under hypoxic stress and stimulated CD8+ T cell activation, concomitantly with the repression of immune suppressive target genes and their encoded products CD274 (PD-1 ligand), CD32B (inhibitory Fcγ receptor IIB) and indoleamine 2,3-dioxygenase 1 (IDO-1), as well as a diminished release of the immune suppressive IDO-1 metabolite kynurenine. Comparison with published data revealed a significant overlap of the PPARβ/δ transcriptome with coexpression modules characteristic of both anti-inflammatory and pro-inflammatory cytokines. Our findings indicate that PPARβ/δ agonists induce a unique macrophage activation state with strong anti-inflammatory but also specific immune stimulatory components, pointing to a context-dependent function of PPARβ/δ in immune regulation.
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Affiliation(s)
- Till Adhikary
- Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology (ZTI), Philipps University, 35043 Marburg, Germany
| | - Annika Wortmann
- Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology (ZTI), Philipps University, 35043 Marburg, Germany
| | - Tim Schumann
- Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology (ZTI), Philipps University, 35043 Marburg, Germany
| | - Florian Finkernagel
- Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology (ZTI), Philipps University, 35043 Marburg, Germany
| | - Sonja Lieber
- Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology (ZTI), Philipps University, 35043 Marburg, Germany
| | - Katrin Roth
- Cellular Imaging Core Facility, Philipps University, Center for Tumor Biology and Immunology (ZTI), 35043 Marburg, Germany
| | - Philipp M Toth
- Medicinal Chemistry Core Facility and Institute of Pharmaceutical Chemistry, Center for Tumor Biology and Immunology (ZTI), Philipps University, 35043 Marburg, Germany
| | - Wibke E Diederich
- Medicinal Chemistry Core Facility and Institute of Pharmaceutical Chemistry, Center for Tumor Biology and Immunology (ZTI), Philipps University, 35043 Marburg, Germany
| | - Andrea Nist
- Genomics Core Facility, Center for Tumor Biology and Immunology (ZTI), Philipps University, 35043 Marburg, Germany
| | - Thorsten Stiewe
- Genomics Core Facility, Center for Tumor Biology and Immunology (ZTI), Philipps University, 35043 Marburg, Germany
| | - Lara Kleinesudeik
- Clinic for Gynecology, Gynecological Oncology and Gynecological Endocrinology, Center for Tumor Biology and Immunology (ZTI), Philipps University, 35043 Marburg, Germany
| | - Silke Reinartz
- Clinic for Gynecology, Gynecological Oncology and Gynecological Endocrinology, Center for Tumor Biology and Immunology (ZTI), Philipps University, 35043 Marburg, Germany
| | - Sabine Müller-Brüsselbach
- Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology (ZTI), Philipps University, 35043 Marburg, Germany
| | - Rolf Müller
- Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology (ZTI), Philipps University, 35043 Marburg, Germany
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15
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Giordano Attianese GMP, Desvergne B. Integrative and systemic approaches for evaluating PPARβ/δ (PPARD) function. NUCLEAR RECEPTOR SIGNALING 2015; 13:e001. [PMID: 25945080 PMCID: PMC4419664 DOI: 10.1621/nrs.13001] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 03/09/2015] [Indexed: 12/13/2022]
Abstract
The peroxisome proliferator-activated receptors (PPARs) are a group of nuclear receptors that function as transcription factors regulating the expression of genes involved in cellular differentiation, development, metabolism and also tumorigenesis. Three PPAR isotypes (α, β/δ and γ) have been identified, among which PPARβ/δ is the most difficult to functionally examine due to its tissue-specific diversity in cell fate determination, energy metabolism and housekeeping activities. PPARβ/δ acts both in a ligand-dependent and -independent manner. The specific type of regulation, activation or repression, is determined by many factors, among which the type of ligand, the presence/absence of PPARβ/δ-interacting corepressor or coactivator complexes and PPARβ/δ protein post-translational modifications play major roles. Recently, new global approaches to the study of nuclear receptors have made it possible to evaluate their molecular activity in a more systemic fashion, rather than deeply digging into a single pathway/function. This systemic approach is ideally suited for studying PPARβ/δ, due to its ubiquitous expression in various organs and its overlapping and tissue-specific transcriptomic signatures. The aim of the present review is to present in detail the diversity of PPARβ/δ function, focusing on the different information gained at the systemic level, and describing the global and unbiased approaches that combine a systems view with molecular understanding.
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16
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Affiliation(s)
- Wataru Mizunoya
- Department of Bioresource Sciences, Faculty of Agriculture, Kyushu University
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17
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Li Y, Teng C. Angiopoietin-like proteins 3, 4 and 8: regulating lipid metabolism and providing new hope for metabolic syndrome. J Drug Target 2014; 22:679-87. [PMID: 24960069 DOI: 10.3109/1061186x.2014.928715] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Angiopoietin-like proteins (ANGPTLs) are a group of eight proteins that share structural similarity to the members of the angiopoietin protein family. ANGPTL3 plays a vital role in the regulation of the plasma levels of triglyceride and cholesterol, mainly via reversible inhibition of the lipoprotein lipase activity. ANGPTL4, which functions as a homo-oligomer different from ANGPTL3 and ANGPTL8, not only regulates the plasma levels of triglyceride and prevents the uptake of dietary lipids into adipose tissues but also inhibits intravascular lipolysis. ANGPTL8 (also called betatrophin) has been identified as an important factor in regulating the triglyceride levels and adipose tissue mass as well as in replenishing the adipose tissue triglyceride store. ANGPTL8 acts together with ANGPTL3 to regulate the lipid metabolism, and ANGPTL8 promotes cleavage of ANGPTL3 to augment the activity of ANGPTL3. In addition, ANGPTL8 promotes proliferation of pancreatic β-cells and enhances insulin secretion. The properties of ANGPTLs in regulating the lipid metabolism suggest their application in the target therapy for metabolic syndrome. As ANGPTLs are regulated by several factors and may be involved in certain specific pathways of lipid metabolism, designing drugs that target ANGPTLs or factors regulating ANGPTLs may be an efficient approach to treat metabolic syndrome.
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Affiliation(s)
- Yunchao Li
- Laboratory of Animal Development Biology, College of Life Science, Northeast Forestry University, Ministry of Education , Harbin , China
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18
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Frenzel E, Wrenger S, Immenschuh S, Koczulla R, Mahadeva R, Deeg HJ, Dinarello CA, Welte T, Marcondes AMQ, Janciauskiene S. Acute-Phase Protein α1-Antitrypsin—A Novel Regulator of Angiopoietin-like Protein 4 Transcription and Secretion. THE JOURNAL OF IMMUNOLOGY 2014; 192:5354-5362. [DOI: 10.4049/jimmunol.1400378] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
Abstract
The angiopoietin-like protein 4 (angptl4, also known as peroxisome proliferator–activated receptor [PPAR]γ–induced angiopoietin-related protein) is a multifunctional protein associated with acute-phase response. The mechanisms accounting for the increase in angptl4 expression are largely unknown. This study shows that human α1-antitrypsin (A1AT) upregulates expression and release of angplt4 in human blood adherent mononuclear cells and in primary human lung microvascular endothelial cells in a concentration- and time-dependent manner. Mononuclear cells treated for 1 h with A1AT (from 0.1 to 4 mg/ml) increased mRNA of angptl4 from 2- to 174-fold, respectively, relative to controls. In endothelial cells, the maximal effect on angptl4 expression was achieved at 8 h with 2 mg/ml A1AT (11-fold induction versus controls). In 10 emphysema patients receiving A1AT therapy (Prolastin), plasma angptl4 levels were higher relative to patients without therapy (nanograms per milliliter, mean [95% confidence interval] 127.1 [99.5–154.6] versus 76.8 [54.8–98.8], respectively, p = 0.045) and correlated with A1AT levels. The effect of A1AT on angptl4 expression was significantly diminished in cells pretreated with a specific inhibitor of ERK1/2 activation (UO126), irreversible and selective PPARγ antagonist (GW9662), or genistein, a ligand for PPARγ. GW9662 did not alter the ability of A1AT to induce ERK1/2 phosphorylation, suggesting that PPARγ is a critical mediator in the A1AT-driven angptl4 expression. In contrast, the forced accumulation of HIF-1α, an upregulator of angptl4 expression, enhanced the effect of A1AT. Thus, acute-phase protein A1AT is a physiological regulator of angptl4, another acute-phase protein.
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Affiliation(s)
- Eileen Frenzel
- *Department of Respiratory Medicine, Hannover Medical School, 30625 Hannover, Germany
| | - Sabine Wrenger
- *Department of Respiratory Medicine, Hannover Medical School, 30625 Hannover, Germany
| | - Stephan Immenschuh
- †Institute for Transfusion Medicine, Hannover Medical School, 30625 Hannover, Germany
| | - Rembert Koczulla
- ‡Division of Pulmonary Diseases, Department of Internal Medicine, Philipps-Universität Marburg, 35037 Marburg, Germany
| | - Ravi Mahadeva
- §Department of Respiratory Medicine, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - H. Joachim Deeg
- ¶Department of Medicine, University of Washington, Seattle, WA 98195
- ‖Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109; and
| | | | - Tobias Welte
- *Department of Respiratory Medicine, Hannover Medical School, 30625 Hannover, Germany
| | - A. Mario Q. Marcondes
- ¶Department of Medicine, University of Washington, Seattle, WA 98195
- ‖Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109; and
| | - Sabina Janciauskiene
- *Department of Respiratory Medicine, Hannover Medical School, 30625 Hannover, Germany
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Tabuchi M, Hayakawa S, Honda E, Ooshima K, Itoh T, Yoshida K, Park AM, Higashino H, Isemura M, Munakata H. Epigallocatechin-3-gallate suppresses transforming growth factor-beta signaling by interacting with the transforming growth factor-beta type II receptor. World J Exp Med 2013; 3:100-107. [DOI: 10.5493/wjem.v3.i4.100] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 07/12/2013] [Accepted: 09/18/2013] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the (-)-epigallocatechin-3-gallate (EGCG) binding to transforming growth factor-β (TGF-β) type II receptor (TGFRII).
METHODS: The expression of α-smooth muscle actin (α-SMA) was used as a marker for fibrotic change in human lung fibroblast MRC-5 cells. The α-SMA expression level was determined by western blotting and immunohistological analysis. We examined whether the anti-fibrotic effects of EGCG on MRC-5 cells was dependent on antioxidant mechanism by using edaravone and N-acetylcysteine (NAC). The suppression effects of EGCG on Smad2/3 activation were studied by confocal fluorescence microscopy. The binding of EGCG to recombinant TGFRII protein was analyzed by immunoprecipitation and affinity chromatography.
RESULTS: When MRC-5 cells were treated with TGF-β, EGCG decreased the expression of α-SMA in a dose dependent manner, whereas catechin did not influence the α-SMA expression in the cells. Except for EGCG, antioxidant compounds (e.g., edaravone and NAC) had no effects on the TGF-β-induced α-SMA expression. Nuclear localization of phosphorylated Smad2/3 was observed after TGF-β treatment; however, EGCG treatment attenuated the nuclear transportation of Smad2/3 in the presence or absence of TGF-β. After a TGFRII expression vector was introduced into COS-7 cells, cell lysates were untreated or treated with EGCG or catechin. The immunoprecipitation experiments using the lysates showed that EGCG dose-dependently bound to TGFRIIand that catechin did not at all. Affinity chromatography study indicated that EGCG would bind to TGFRII.
CONCLUSION: Our results demonstrate that EGCG interacts with TGFRII and inhibits the expression of α-SMA via the TGF-β-Smad2/3 pathway in human lung fibroblast MRC-5 cells.
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Alteration of energy substrates and ROS production in diabetic cardiomyopathy. Mediators Inflamm 2013; 2013:461967. [PMID: 24288443 PMCID: PMC3833358 DOI: 10.1155/2013/461967] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 09/18/2013] [Accepted: 09/20/2013] [Indexed: 01/01/2023] Open
Abstract
Diabetic cardiomyopathy is initiated by alterations in energy substrates. Despite excess of plasma glucose and lipids, the diabetic heart almost exclusively depends on fatty acid degradation. Glycolytic enzymes and transporters are impaired by fatty acid metabolism, leading to accumulation of glucose derivatives. However, fatty acid oxidation yields lower ATP production per mole of oxygen than glucose, causing mitochondrial uncoupling and decreased energy efficiency. In addition, the oxidation of fatty acids can saturate and cause their deposition in the cytosol, where they deviate to induce toxic metabolites or gene expression by nuclear-receptor interaction. Hyperglycemia, the fatty acid oxidation pathway, and the cytosolic storage of fatty acid and glucose/fatty acid derivatives are major inducers of reactive oxygen species. However, the presence of these species can be essential for physiological responses in the diabetic myocardium.
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21
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Tan HC, Poh CK, Cai Y, Wang W. Anti-fibrosis effect of BMP-7 peptide functionalization on cobalt chromium alloy. J Orthop Res 2013; 31:983-90. [PMID: 23456668 DOI: 10.1002/jor.22313] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 12/20/2012] [Indexed: 02/04/2023]
Abstract
Orthopedic metallic prosthetic implants are commonly made of cobalt chromium (CoCr) alloys. However, such metal-based implants are susceptible to fibrous capsule formation on the implant surface after implantation. At the bone-implant interface, this capsule can prevent implant integration, resulting in loosening and failure. Minimizing the development of such a capsule on the CoCr surface would improve direct bone-implant bonding leading to long-term implant functionality. We evaluated the anti-fibrosis effect of bone morphogenic protein-7 (BMP-7) peptide covalently bonded to CoCr alloy. This peptide, a biomimetic derivation of the knuckle epitope of BMP-7, was conjugated at the N-terminus with a cysteine amino acid. X-ray photoelectron spectroscopy (XPS) and probe binding assay were used to evaluate different stages of grafting and surface functionalization using polydopamine coating. Cellular functions were studied using fibroblast attachment, cell proliferation, and MTT assays. Fibroblasts were grown on functionalized and pristine CoCr substrates, and the efficacy of BMP-7 peptide on anti-fibrosis was analyzed via gene expression and protein expression of fibrosis markers ACTA2, Collagen 1A1, and fibronectin. The peptide functionalized substrates showed significant reduction of fibrosis markers expression after 1 week of incubation compared to controls. BMP-7 signaling pathway activation was shown by the presence of phosphorylation of Smad1/5/8. These findings may contribute to the improvement of CoCr implants in orthopedic surgery applications.
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Affiliation(s)
- Hark Chuan Tan
- Department of Orthopaedic Surgery, National University of Singapore, Kent Ridge, Singapore 119074, Singapore
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22
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Stockert J, Wolf A, Kaddatz K, Schnitzer E, Finkernagel F, Meissner W, Müller-Brüsselbach S, Kracht M, Müller R. Regulation of TAK1/TAB1-mediated IL-1β signaling by cytoplasmic PPARβ/δ. PLoS One 2013; 8:e63011. [PMID: 23646170 PMCID: PMC3639976 DOI: 10.1371/journal.pone.0063011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 03/27/2013] [Indexed: 11/19/2022] Open
Abstract
The peroxisome proliferator-activated receptor subtypes PPARα, PPARβ/δ, PPARγ are members of the steroid hormone receptor superfamily with well-established functions in transcriptional regulation. Here, we describe an unexpected cytoplasmic function of PPARβ/δ. Silencing of PPARβ/δ expression interferes with the expression of a large subset of interleukin-1β (IL-1β)-induced target genes in HeLa cells, which is preceded by an inhibition of the IL-1β-induced phosphorylation of TAK1 and its downstream effectors, including the NFκBα inhibitor IκBα (NFKBIA) and the NFκBα subunit p65 (RELA). PPARβ/δ enhances the interaction between TAK1 and the small heat-shock protein HSP27, a known positive modulator of TAK1-mediated IL-1β signaling. Consistent with these findings, PPARβ/δ physically interacts with both the endogenous cytoplasmic TAK1/TAB1 complex and HSP27, and PPARβ/δ overexpression increases the TAK1-induced transcriptional activity of NFκB. These observations suggest that PPARβ/δ plays a role in the assembly of a cytoplasmic multi-protein complex containing TAK1, TAB1, HSP27 and PPARβ/δ, and thereby participates in the NFκB response to IL-1β.
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Affiliation(s)
- Josefine Stockert
- Institute of Molecular Biology and Tumor Research (IMT), Philipps University, Marburg, Germany
| | - Alexander Wolf
- Rudolf Buchheim Institute for Pharmacology, Giessen, Germany
| | - Kerstin Kaddatz
- Institute of Molecular Biology and Tumor Research (IMT), Philipps University, Marburg, Germany
| | - Evelyn Schnitzer
- Institute of Molecular Biology and Tumor Research (IMT), Philipps University, Marburg, Germany
| | - Florian Finkernagel
- Institute of Molecular Biology and Tumor Research (IMT), Philipps University, Marburg, Germany
| | - Wolfgang Meissner
- Institute of Molecular Biology and Tumor Research (IMT), Philipps University, Marburg, Germany
| | | | - Michael Kracht
- Rudolf Buchheim Institute for Pharmacology, Giessen, Germany
| | - Rolf Müller
- Institute of Molecular Biology and Tumor Research (IMT), Philipps University, Marburg, Germany
- * E-mail:
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Abstract
Besides its established functions in intermediary metabolism and developmental processes, the nuclear receptor peroxisome proliferator-activated receptor β/δ (PPARβ/δ) has a less defined role in tumorigenesis. In the present study, we have identified a function for PPARβ/δ in cancer cell invasion. We show that two structurally divergent inhibitory ligands for PPARβ/δ, the inverse agonists ST247 and DG172, strongly inhibit the serum- and transforming growth factor β (TGFβ)-induced invasion of MDA-MB-231 human breast cancer cells into a three-dimensional matrigel matrix. To elucidate the molecular basis of this finding, we performed chromatin immunoprecipitation sequencing (ChIP-Seq) and microarray analyses, which identified the gene encoding angiopoietin-like 4 (ANGPTL4) as the major transcriptional PPARβ/δ target in MDA-MB-231 cells, previously implicated in TGFβ-mediated tumor progression and metastatic dissemination. We show that the induction of ANGPTL4 by TGFβ and other oncogenic signals is strongly repressed by ST247 and DG172 in a PPARβ/δ-dependent fashion, resulting in the inhibition of ANGPTL4 secretion. This effect is attributable to these ligands' ability to induce a dominant transcriptional repressor complex at the site of transcription initiation that blocks preinitiation complex formation through an histone deacetylase-independent, non-canonical mechanism. Repression of ANGPTL4 transcription by inverse PPARβ/δ agonists is functionally linked to the inhibition of cancer cell invasion into a three-dimensional matrix, as (i) invasion of MDA-MB-231 cells is critically dependent on ANGPTL4 expression, (ii) recombinant ANGPTL4 stimulates invasion, and (iii) reverses the inhibitory effect of ST247 and DG172. These findings indicate that a PPARβ/δ-ANGPTL4 pathway is involved in the regulation of tumor cell invasion and that its pharmacological manipulation by inverse PPARβ/δ agonists is feasible.
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Regulation of triglyceride metabolism by Angiopoietin-like proteins. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:782-9. [DOI: 10.1016/j.bbalip.2011.10.010] [Citation(s) in RCA: 128] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 10/07/2011] [Accepted: 10/10/2011] [Indexed: 12/30/2022]
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Köllmer M, Keskar V, Hauk TG, Collins JM, Russell B, Gemeinhart RA. Stem cell-derived extracellular matrix enables survival and multilineage differentiation within superporous hydrogels. Biomacromolecules 2012; 13:963-73. [PMID: 22404228 DOI: 10.1021/bm300332w] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Hydrophilic poly(ethylene glycol) diacrylate (PEGDA) hydrogel surfaces resist protein adsorption and are generally thought to be unsuitable for anchorage-dependent cells to adhere. Intriguingly, our previous findings revealed that PEGDA superporous hydrogel scaffolds (SPHs) allow anchorage of bone marrow derived human mesenchymal stem cells (hMSCs) and support their long-term survival. Therefore, we hypothesized that the physicochemical characteristics of the scaffold impart properties that could foster cellular responses. We examined if hMSCs alter their microenvironment to allow cell attachment by synthesizing their own extracellular matrix (ECM) proteins. Immunofluorescence staining revealed extensive expression of collagen type I, collagen type IV, laminin, and fibronectin within hMSC-seeded SPHs by the end of the third week. Whether cultured in serum-free or serum-supplemented medium, hMSC ECM protein gene expression patterns exhibited no substantial changes. The presence of serum proteins is required for initial anchorage of hMSCs within the SPHs but not for the hMSC survival after 24 h. In contrast to 2D expansion on tissue culture plastic (TCP), hMSCs cultured within SPHs proliferate similarly in the presence or absence of serum. To test whether hMSCs retain their undifferentiated state within the SPHs, cell-seeded constructs were cultured for 3 weeks in stem cell maintenance medium and the expression of hMSC-specific cell surface markers were evaluated by flow cytometry. CD105, CD90, CD73, and CD44 were present to a similar extent in the SPH and in 2D monolayer culture. We further demonstrated multilineage potential of hMSCs grown in the PEGDA SPHs, whereby differentiation into osteoblasts, chondrocytes, and adipocytes could be induced. The present study demonstrates the potential of hMSCs to alter the "blank" PEGDA environment to a milieu conducive to cell growth and multilineage differentiation by secreting adhesive ECM proteins within the porous network of the SPH scaffolds.
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Affiliation(s)
- Melanie Köllmer
- Department of Biopharmaceutical Sciences, University of Illinois, Chicago, Illinois 60612-7231, United States
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26
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Lieber S, Scheer F, Meissner W, Naruhn S, Adhikary T, Müller-Brüsselbach S, Diederich WE, Müller R. (Z)-2-(2-Bromophenyl)-3-{[4-(1-methyl-piperazine)amino]phenyl}acrylonitrile (DG172): An Orally Bioavailable PPARβ/δ-Selective Ligand with Inverse Agonistic Properties. J Med Chem 2012; 55:2858-68. [DOI: 10.1021/jm2017122] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sonja Lieber
- Institute of Molecular Biology and Tumor Research (IMT), Philipps
University, Emil-Mannkopff-Strasse 2, 35033 Marburg, Germany
| | - Frithjof Scheer
- Institute of Pharmaceutical Chemistry,
Philipps-University, Marbacher Weg 6, 35032 Marburg, Germany
| | - Wolfgang Meissner
- Institute of Molecular Biology and Tumor Research (IMT), Philipps
University, Emil-Mannkopff-Strasse 2, 35033 Marburg, Germany
| | - Simone Naruhn
- Institute of Molecular Biology and Tumor Research (IMT), Philipps
University, Emil-Mannkopff-Strasse 2, 35033 Marburg, Germany
| | - Till Adhikary
- Institute of Molecular Biology and Tumor Research (IMT), Philipps
University, Emil-Mannkopff-Strasse 2, 35033 Marburg, Germany
| | - Sabine Müller-Brüsselbach
- Institute of Molecular Biology and Tumor Research (IMT), Philipps
University, Emil-Mannkopff-Strasse 2, 35033 Marburg, Germany
| | - Wibke E. Diederich
- Institute of Pharmaceutical Chemistry,
Philipps-University, Marbacher Weg 6, 35032 Marburg, Germany
| | - Rolf Müller
- Institute of Molecular Biology and Tumor Research (IMT), Philipps
University, Emil-Mannkopff-Strasse 2, 35033 Marburg, Germany
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27
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Abstract
The past decade has seen a rapid development and increasing recognition of ANGPTL4 (angiopoietin-like 4) as a remarkably multifaceted protein that is involved in many metabolic and non-metabolic conditions. ANGPTL4 has been recognised as a central player in various aspects of energy homoeostasis, at least in part, via the inhibitory interaction between the coiled-coil domain of ANGPTL4 and LPL (lipoprotein lipase). The fibrinogen-like domain of ANGPTL4 interacts and activates specific integrins to facilitate wound healing, modulates vascular permeability, and regulates ROS (reactive oxygen species) level to promote tumorigenesis. The present review summarizes these landmark findings about ANGPTL4 and highlights several important implications for future clinical practice. Importantly, these implications have also raised many questions that are in urgent need of further investigations, particularly the transcription regulation of ANGPTL4 expression, and the post-translation cleavage and modifications of ANGPTL4. The research findings over the past decade have laid the foundation for a better mechanistic understanding of the new scientific discoveries on the diverse roles of ANGPTL4.
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28
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Peters JM, Morales JL, Gonzalez FJ. Modulation of gastrointestinal inflammation and colorectal tumorigenesis by peroxisome proliferator-activated receptor-β/δ (PPARβ/δ). ACTA ACUST UNITED AC 2011; 8:e85-e93. [PMID: 22611424 DOI: 10.1016/j.ddmec.2011.11.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Critical physiological roles of peroxisome proliferator-activated receptor-β/δ (PPARβ/δ) include the regulation glucose and lipid homeostasis, cellular differentiation, and modulation of inflammation. The potential for targeting PPARβ/δ for the prevention and treatment of metabolic diseases or cancer, is compromised because of major inconsistencies in the literature. This is due primarily to uncertainty regarding the effect of PPARβ/δ and its activation on cell proliferation, apoptosis and cell survival. This review summarizes both the confirmed and conflicting mechanisms that have been described for PPARβ/δ and the potential for targeting this nuclear receptor for the prevention and treatment of colon cancer.
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Affiliation(s)
- Jeffrey M Peters
- Department of Veterinary and Biomedical Sciences and The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA
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29
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Naruhn S, Toth PM, Adhikary T, Kaddatz K, Pape V, Dörr S, Klebe G, Müller-Brüsselbach S, Diederich WE, Müller R. High-affinity peroxisome proliferator-activated receptor β/δ-specific ligands with pure antagonistic or inverse agonistic properties. Mol Pharmacol 2011; 80:828-38. [PMID: 21862691 DOI: 10.1124/mol.111.074039] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Peroxisome proliferator-activated receptor β/δ (PPARβ/δ) is a ligand-regulated nuclear receptor with essential functions in metabolism and inflammation. We have synthesized a new derivative [methyl 3-(N-(4-(hexylamino)-2-methoxyphenyl)sulfamoyl)thiophene-2-carboxylate (ST247) structurally related to the published PPARβ/δ inhibitory ligand methyl 3-(N-(2-methoxy-4-(phenylamino)phenyl)sulfamoyl)thiophene-2-carboxylate (GSK0660). ST247 has a higher affinity to PPARβ/δ than GSK0660, and at equimolar concentrations, it more efficiently 1) induces the interaction with corepressors both in vitro and in vivo, 2) inhibits the agonist-induced transcriptional activity of PPARβ/δ, and 3) down-regulates basal level expression of the peroxisome proliferator responsive element-driven PPARβ/δ target gene ANGPTL4. Methyl 3-(N-(4-(tert-butylamino)-2-methoxyphenyl)sulfamoyl)thiophene-2-carboxylate (PT-S58), another high-affinity derivative from our series, also efficiently inhibits agonist-induced transcriptional activation, but in contrast to ST247, it does not enhance the interaction of PPARβ/δ with corepressors. PT-S58 rather prevents corepressor recruitment triggered by the inverse agonist ST247. These findings classify ST247 as an inverse agonist, whereas PT-S58 is the first pure PPARβ/δ antagonist described to date. It is noteworthy that ST247 and PT-S58 are also effective on PPRE-independent functions of PPARβ/δ: in monocytic cells, both ligands modulate expression of the activation marker CCL2 in the opposite direction as an established PPARβ/δ agonist. The possibility to differentially modulate specific functions of PPARβ/δ makes these novel compounds invaluable tools to advance our understanding of PPARβ/δ biology.
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Affiliation(s)
- Simone Naruhn
- Institute of Molecular Biology and Tumor Research (IMT), Philipps University, Marburg, Germany
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30
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Adhikary T, Kaddatz K, Finkernagel F, Schönbauer A, Meissner W, Scharfe M, Jarek M, Blöcker H, Müller-Brüsselbach S, Müller R. Genomewide analyses define different modes of transcriptional regulation by peroxisome proliferator-activated receptor-β/δ (PPARβ/δ). PLoS One 2011; 6:e16344. [PMID: 21283829 PMCID: PMC3023804 DOI: 10.1371/journal.pone.0016344] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Accepted: 12/11/2010] [Indexed: 11/26/2022] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors with essential functions in lipid, glucose and energy homeostasis, cell differentiation, inflammation and metabolic disorders, and represent important drug targets. PPARs heterodimerize with retinoid X receptors (RXRs) and can form transcriptional activator or repressor complexes at specific DNA elements (PPREs). It is believed that the decision between repression and activation is generally governed by a ligand-mediated switch. We have performed genomewide analyses of agonist-treated and PPARβ/δ-depleted human myofibroblasts to test this hypothesis and to identify global principles of PPARβ/δ-mediated gene regulation. Chromatin immunoprecipitation sequencing (ChIP-Seq) of PPARβ/δ, H3K4me3 and RNA polymerase II enrichment sites combined with transcriptional profiling enabled the definition of 112 bona fide PPARβ/δ target genes showing either of three distinct types of transcriptional response: (I) ligand-independent repression by PPARβ/δ; (II) ligand-induced activation and/or derepression by PPARβ/δ; and (III) ligand-independent activation by PPARβ/δ. These data identify PPRE-mediated repression as a major mechanism of transcriptional regulation by PPARβ/δ, but, unexpectedly, also show that only a subset of repressed genes are activated by a ligand-mediated switch. Our results also suggest that the type of transcriptional response by a given target gene is connected to the structure of its associated PPRE(s) and the biological function of its encoded protein. These observations have important implications for understanding the regulatory PPAR network and PPARβ/δ ligand-based drugs.
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Affiliation(s)
- Till Adhikary
- Institute of Molecular Biology and Tumor Research (IMT), Philipps University, Marburg, Germany
| | - Kerstin Kaddatz
- Institute of Molecular Biology and Tumor Research (IMT), Philipps University, Marburg, Germany
| | - Florian Finkernagel
- Institute of Molecular Biology and Tumor Research (IMT), Philipps University, Marburg, Germany
| | - Anne Schönbauer
- Institute of Molecular Biology and Tumor Research (IMT), Philipps University, Marburg, Germany
| | - Wolfgang Meissner
- Institute of Molecular Biology and Tumor Research (IMT), Philipps University, Marburg, Germany
| | - Maren Scharfe
- Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - Michael Jarek
- Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - Helmut Blöcker
- Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | | | - Rolf Müller
- Institute of Molecular Biology and Tumor Research (IMT), Philipps University, Marburg, Germany
- * E-mail:
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