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Nakadai T, Shimada M, Ito K, Cevher MA, Chu CS, Kumegawa K, Maruyama R, Malik S, Roeder RG. Two target gene activation pathways for orphan ERR nuclear receptors. Cell Res 2023; 33:165-183. [PMID: 36646760 PMCID: PMC9892517 DOI: 10.1038/s41422-022-00774-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 12/02/2022] [Indexed: 01/18/2023] Open
Abstract
Estrogen-related receptors (ERRα/β/γ) are orphan nuclear receptors that function in energy-demanding physiological processes, as well as in development and stem cell maintenance, but mechanisms underlying target gene activation by ERRs are largely unknown. Here, reconstituted biochemical assays that manifest ERR-dependent transcription have revealed two complementary mechanisms. On DNA templates, ERRs activate transcription with just the normal complement of general initiation factors through an interaction of the ERR DNA-binding domain with the p52 subunit of initiation factor TFIIH. On chromatin templates, activation by ERRs is dependent on AF2 domain interactions with the cell-specific coactivator PGC-1α, which in turn recruits the ubiquitous p300 and MED1/Mediator coactivators. This role of PGC-1α may also be fulfilled by other AF2-interacting coactivators like NCOA3, which is shown to recruit Mediator selectively to ERRβ and ERRγ. Importantly, combined genetic and RNA-seq analyses establish that both the TFIIH and the AF2 interaction-dependent pathways are essential for ERRβ/γ-selective gene expression and pluripotency maintenance in embryonic stem cells in which NCOA3 is a critical coactivator.
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Affiliation(s)
- Tomoyoshi Nakadai
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY, USA
- Project for Cancer Epigenomics, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Miho Shimada
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY, USA
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, Yokohama, Japan
| | - Keiichi Ito
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY, USA
| | - Murat Alper Cevher
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY, USA
- Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey
| | - Chi-Shuen Chu
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY, USA
| | - Kohei Kumegawa
- Cancer Cell Diversity Project, NEXT-Ganken Program, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Reo Maruyama
- Project for Cancer Epigenomics, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Sohail Malik
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY, USA
| | - Robert G Roeder
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY, USA.
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Lanzafame M, Nardo T, Ricotti R, Pantaleoni C, D'Arrigo S, Stanzial F, Benedicenti F, Thomas MA, Stefanini M, Orioli D, Botta E. TFIIH stabilization recovers the DNA repair and transcription dysfunctions in thermo-sensitive trichothiodystrophy. Hum Mutat 2022; 43:2222-2233. [PMID: 36259739 DOI: 10.1002/humu.24488] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/19/2022] [Accepted: 10/17/2022] [Indexed: 01/25/2023]
Abstract
Trichothiodystrophy (TTD) is a rare hereditary disease whose prominent feature is brittle hair. Additional clinical signs are physical and neurodevelopmental abnormalities and in about half of the cases hypersensitivity to UV radiation. The photosensitive form of TTD (PS-TTD) is most commonly caused by mutations in the ERCC2/XPD gene encoding a subunit of the transcription/DNA repair complex TFIIH. Here we report novel ERCC2/XPD mutations affecting proper protein folding, which generate thermo-labile forms of XPD associated with thermo-sensitive phenotypes characterized by reversible aggravation of TTD clinical signs during episodes of fever. In patient cells, the newly identified XPD variants result in thermo-instability of the whole TFIIH complex and consequent temperature-dependent defects in DNA repair and transcription. Improving the protein folding process by exposing patient cells to low temperature or to the chemical chaperone glycerol allowed rescue of TFIIH thermo-instability and a concomitant recovery of the complex activities. Besides providing a rationale for the peculiar thermo-sensitive clinical features of these new cases, the present findings demonstrate how variations in the cellular concentration of mutated TFIIH impact the cellular functions of the complex and underlie how both quantitative and qualitative TFIIH alterations contribute to TTD clinical features.
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Affiliation(s)
- Manuela Lanzafame
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza" (IGM) CNR, Pavia, Italy
| | - Tiziana Nardo
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza" (IGM) CNR, Pavia, Italy
| | - Roberta Ricotti
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza" (IGM) CNR, Pavia, Italy
| | - Chiara Pantaleoni
- Dipartimento Neuroscienze Pediatriche, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Stefano D'Arrigo
- Dipartimento Neuroscienze Pediatriche, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Franco Stanzial
- Genetic Counseling Service, Department of Pediatrics, Regional Hospital of Bolzano, Bolzano, Italy
| | - Francesco Benedicenti
- Genetic Counseling Service, Department of Pediatrics, Regional Hospital of Bolzano, Bolzano, Italy
| | - Mary A Thomas
- Department of Medical Genetics, Cumming, School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Miria Stefanini
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza" (IGM) CNR, Pavia, Italy
| | - Donata Orioli
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza" (IGM) CNR, Pavia, Italy
| | - Elena Botta
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza" (IGM) CNR, Pavia, Italy
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3
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Ercc2/Xpd deficiency results in failure of digestive organ growth in zebrafish with elevated nucleolar stress. iScience 2022; 25:104957. [PMID: 36065184 PMCID: PMC9440294 DOI: 10.1016/j.isci.2022.104957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/23/2022] [Accepted: 08/12/2022] [Indexed: 12/09/2022] Open
Abstract
Mutations in ERCC2/XPD helicase, an important component of the TFIIH complex, cause distinct human genetic disorders which exhibit various pathological features. However, the molecular mechanisms underlying many symptoms remain elusive. Here, we have shown that Ercc2/Xpd deficiency in zebrafish resulted in hypoplastic digestive organs with normal bud initiation but later failed to grow. The proliferation of intestinal endothelial cells was impaired in ercc2/xpd mutants, and mitochondrial abnormalities, autophagy, and inflammation were highly induced. Further studies revealed that these abnormalities were associated with the perturbation of rRNA synthesis and nucleolar stress in a p53-independent manner. As TFIIH has only been implicated in RNA polymerase I-dependent transcription in vitro, our results provide the first evidence for the connection between Ercc2/Xpd and rRNA synthesis in an animal model that recapitulates certain key characteristics of ERCC2/XPD-related human genetic disorders, and will greatly advance our understanding of the molecular pathogenesis of these diseases. Ercc2/Xpd deficiency results in failure of digestive organ growth in zebrafish Ercc2/Xpd-deficient intestinal endothelial cells exhibit impaired proliferation Mitochondrial abnormalities, autophagy, and inflammation are highly induced rRNA synthesis perturbation leads to nucleolar stress in a p53-independent manner
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Li X, Zheng L, Zhang B, Deng ZY, Luo T. The Structure Basis of Phytochemicals as Metabolic Signals for Combating Obesity. Front Nutr 2022; 9:913883. [PMID: 35769384 PMCID: PMC9234462 DOI: 10.3389/fnut.2022.913883] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 05/23/2022] [Indexed: 12/12/2022] Open
Abstract
The consumption of phytochemicals, bioactive compounds in fruits and vegetables, has been demonstrated to ameliorate obesity and related metabolic symptoms by regulating specific metabolic pathways. This review summarizes the progress made in our understanding of the potential of phytochemicals as metabolic signals: we discuss herein selected molecular mechanisms which are involved in the occurrence of obesity that may be regulated by phytochemicals. The focus of our review highlights the regulation of transcription factors toll like receptor 4 (TLR4), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), the peroxisome proliferator-activated receptors (PPARs), fat mass and obesity-associated protein (FTO) and regulation of microRNAs (miRNA). In this review, the effect of phytochemicals on signaling pathways involved in obesity were discussed on the basis of their chemical structure, suggesting molecular mechanisms for how phytochemicals may impact these signaling pathways. For example, compounds with an isothiocyanate group or an α, β-unsaturated carbonyl group may interact with the TLR4 signaling pathway. Regarding Nrf2, we examine compounds possessing an α, β-unsaturated carbonyl group which binds covalently with the cysteine thiols of Keap1. Additionally, phytochemical activation of PPARs, FTO and miRNAs were summarized. This information may be of value to better understand how specific phytochemicals interact with specific signaling pathways and help guide the development of new drugs to combat obesity and related metabolic diseases.
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Dion V, Schumacher N, Masar N, Pieltain A, Tocquin P, Lesoinne P, Malgrange B, Vandenbosch R, Franzen R. Cyclin-dependent kinase 7 contributes to myelin maintenance in the adult central nervous system and promotes myelin gene expression. Glia 2022; 70:1652-1665. [PMID: 35488490 DOI: 10.1002/glia.24186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 04/08/2022] [Accepted: 04/21/2022] [Indexed: 11/08/2022]
Abstract
Mechanisms regulating oligodendrocyte differentiation, developmental myelination and myelin maintenance in adulthood are complex and still not completely described. Their understanding is crucial for the development of new protective or therapeutic strategies in demyelinating pathologies such as multiple sclerosis. In this perspective, we have investigated the role of Cyclin-dependent kinase 7 (Cdk7), a kinase involved in cell-cycle progression and transcription regulation, in the oligodendroglial lineage. We generated a conditional knock-out mouse model in which Cdk7 is invalidated in post-mitotic oligodendrocytes. At the end of developmental myelination, the number and diameter of myelinated axons, as well as the myelin structure, thickness and protein composition, were normal. However, in young adult and in aged mice, there was a higher number of small caliber myelinated axons associated with a decreased mean axonal diameter, myelin sheaths of large caliber axons were thinner, and the level of some major myelin-associated proteins was reduced. These defects were accompanied by the appearance of an abnormal clasping phenotype. We also used an in vitro oligodendroglial model and showed that Cdk7 pharmacological inhibition led to an altered myelination-associated morphological modification combined with a decreased expression of myelin-specific genes. Altogether, we identified novel functions for Cdk7 in CNS myelination.
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Affiliation(s)
- Valérie Dion
- Laboratory of Nervous System Disorders and Therapies, GIGA Neurosciences, University of Liège, Liège, Belgium
| | - Nathalie Schumacher
- Laboratory of Nervous System Disorders and Therapies, GIGA Neurosciences, University of Liège, Liège, Belgium
| | - Nathalie Masar
- Laboratory of Nervous System Disorders and Therapies, GIGA Neurosciences, University of Liège, Liège, Belgium
| | - Alexandra Pieltain
- Laboratory of Nervous System Disorders and Therapies, GIGA Neurosciences, University of Liège, Liège, Belgium
| | - Pierre Tocquin
- CARE PhytoSYSTEMS, Integrative Biological Sciences, University of Liège, Liège, Belgium
| | - Pierre Lesoinne
- Laboratory of Nervous System Disorders and Therapies, GIGA Neurosciences, University of Liège, Liège, Belgium
| | - Brigitte Malgrange
- Laboratory of Developmental Neurobiology, GIGA Stem Cells & GIGA Neurosciences, University of Liège, Liège, Belgium
| | - Renaud Vandenbosch
- Laboratory of Developmental Neurobiology, GIGA Stem Cells & GIGA Neurosciences, University of Liège, Liège, Belgium.,Division of Histology, Department of Biomedical and Preclinical Sciences, University of Liège, Liège, Belgium
| | - Rachelle Franzen
- Laboratory of Nervous System Disorders and Therapies, GIGA Neurosciences, University of Liège, Liège, Belgium
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Lin Y, Wang Y, Li PF. PPARα: An emerging target of metabolic syndrome, neurodegenerative and cardiovascular diseases. Front Endocrinol (Lausanne) 2022; 13:1074911. [PMID: 36589809 PMCID: PMC9800994 DOI: 10.3389/fendo.2022.1074911] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 11/23/2022] [Indexed: 12/23/2022] Open
Abstract
Peroxisome proliferator-activated receptor α (PPARα) is a ligand-activated transcription factor that is involved in lipid metabolism of various tissues. Different metabolites of fatty acids and agonists like fibrates activate PPARα for its transactivative or repressive function. PPARα is known to affect diverse human diseases, and we focus on advanced studies of its transcriptional regulation in these diseases. In MAFLD, PPARα shows a protective function with its upregulation of lipid oxidation and mitochondrial biogenesis and transcriptional repression of inflammatory genes, which is similar in Alzheimer's disease and cardiovascular disease. Activation of PPARα also prevents the progress of diabetes complications; however, its role in diabetes and cancers remains uncertain. Some PPARα-specific agonists, such as Wy14643 and fenofibrate, have been applied in metabolic syndrome treatment, which might own potential in wider application. Future studies may further explore the functions and interventions of PPARα in cancer, diabetes, immunological diseases, and neurodegenerative disease.
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Affiliation(s)
- Yijun Lin
- Xiamen Cardiovascular Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
- Xiamen Key Laboratory of Cardiovascular Disease, Xiamen, China
- *Correspondence: Yijun Lin, ; Yan Wang, ; Pei-feng Li,
| | - Yan Wang
- Xiamen Cardiovascular Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
- Xiamen Key Laboratory of Cardiovascular Disease, Xiamen, China
- *Correspondence: Yijun Lin, ; Yan Wang, ; Pei-feng Li,
| | - Pei-feng Li
- Xiamen Cardiovascular Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
- Xiamen Key Laboratory of Cardiovascular Disease, Xiamen, China
- *Correspondence: Yijun Lin, ; Yan Wang, ; Pei-feng Li,
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7
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Thorne JL, Cioccoloni G. Nuclear Receptors and Lipid Sensing. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1390:83-105. [DOI: 10.1007/978-3-031-11836-4_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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8
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Liu Y, Fu L, Wu J, Liu M, Wang G, Liu B, Zhang L. Transcriptional cyclin-dependent kinases: Potential drug targets in cancer therapy. Eur J Med Chem 2021; 229:114056. [PMID: 34942431 DOI: 10.1016/j.ejmech.2021.114056] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 12/14/2021] [Accepted: 12/14/2021] [Indexed: 02/08/2023]
Abstract
In the wake of the development of the concept of cell cycle and its limiting points, cyclin-dependent kinases (CDKs) are considered to play a central role in regulating cell cycle progression. Recent studies have strongly demonstrated that CDKs also has multiple functions, especially in response to extracellular and intracellular signals by interfering with transcriptional events. Consequently, how to inhibit their function has been a hot research topic. It is worth noting that the key role of CDKs in regulating transcription has been explored in recent years, but its related pharmacological targets are less developed, and most inhibitors have not entered the clinical stage. Accordingly, this perspective focus on the biological functions of transcription related CDKs and their complexes, some key upstream and downstream signals, and inhibitors for cancer treatment in recent years. In addition, some corresponding combined treatment strategies will provide a more novel perspective for future cancer remedy.
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Affiliation(s)
- Yi Liu
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, 610031, Chengdu, China
| | - Leilei Fu
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, 610031, Chengdu, China
| | - Junhao Wu
- Department of Otolaryngology, Head and Neck Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Ming Liu
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, 610041, China.
| | - Guan Wang
- State Key Laboratory of Biotherapy and Cancer Center, Innovation Center of Nursing Research, Nursing Key Laboratory of Sichuan Province, West China Hospital, and Collaborative Innovation Center of Biotherapy, Sichuan University, Chengdu, 610041, China.
| | - Bo Liu
- State Key Laboratory of Biotherapy and Cancer Center, Innovation Center of Nursing Research, Nursing Key Laboratory of Sichuan Province, West China Hospital, and Collaborative Innovation Center of Biotherapy, Sichuan University, Chengdu, 610041, China
| | - Lan Zhang
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, 610031, Chengdu, China.
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Muzio G, Barrera G, Pizzimenti S. Peroxisome Proliferator-Activated Receptors (PPARs) and Oxidative Stress in Physiological Conditions and in Cancer. Antioxidants (Basel) 2021; 10:antiox10111734. [PMID: 34829605 PMCID: PMC8614822 DOI: 10.3390/antiox10111734] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 12/18/2022] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs) belong to the nuclear hormone receptor superfamily. Originally described as “orphan nuclear receptors”, they can bind both natural and synthetic ligands acting as agonists or antagonists. In humans three subtypes, PPARα, β/δ, γ, are encoded by different genes, show tissue-specific expression patterns, and contribute to the regulation of lipid and carbohydrate metabolisms, of different cell functions, including proliferation, death, differentiation, and of processes, as inflammation, angiogenesis, immune response. The PPAR ability in increasing the expression of various antioxidant genes and decreasing the synthesis of pro-inflammatory mediators, makes them be considered among the most important regulators of the cellular response to oxidative stress conditions. Based on the multiplicity of physiological effects, PPAR involvement in cancer development and progression has attracted great scientific interest with the aim to describe changes occurring in their expression in cancer cells, and to investigate the correlation with some characteristics of cancer phenotype, including increased proliferation, decreased susceptibility to apoptosis, malignancy degree and onset of resistance to anticancer drugs. This review focuses on mechanisms underlying the antioxidant and anti-inflammatory properties of PPARs in physiological conditions, and on the reported beneficial effects of PPAR activation in cancer.
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10
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Thyroid hormone receptor phosphorylation regulates acute fasting-induced suppression of the hypothalamic-pituitary-thyroid axis. Proc Natl Acad Sci U S A 2021; 118:2107943118. [PMID: 34544870 DOI: 10.1073/pnas.2107943118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/23/2021] [Indexed: 11/18/2022] Open
Abstract
Fasting induces profound changes in the hypothalamic-pituitary-thyroid (HPT) axis. After binding thyroid hormone (TH), the TH receptor beta 2 isoform (THRB2) represses Trh and Tsh subunit genes and is the principle negative regulator of the HPT axis. Using mass spectrometry, we identified a major phosphorylation site in the AF-1 domain of THRB2 (serine 101, S101), which is conserved among many members of the nuclear hormone receptor superfamily. More than 50% of THRB2 is phosphorylated at S101 in cultured thyrotrophs (TαT1.1) and in the mouse pituitary. All other THR isoforms lack this site and exhibit limited overall levels of phosphorylation. To determine the importance of THRB2 S101 phosphorylation, we used the TαT1.1 cell line and S101A mutant knock-in mice (Thrb2 S101A ). We found that TH promoted S101 THRB2 phosphorylation and was essential for repression of the axis at physiologic TH concentrations. In mice, THRB2 phosphorylation was also increased by fasting and mimicked Trh and Tshb repression by TH. In vitro studies demonstrated that a master metabolic sensor, AMP-activated kinase (AMPK) induced phosphorylation at the same site and caused Tshb repression independent of TH. Furthermore, we identified cyclin-dependent kinase 2 (CDK2) as a direct kinase phosphorylating THRB2 S101 and propose that AMPK or TH increase S101 phosphorylation through the activity of CDK2. This study provides a physiologically relevant function for THR phosphorylation, which permits nutritional deprivation and TH to use a common mechanism for acute suppression of the HPT axis.
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Reduced levels of prostaglandin I 2 synthase: a distinctive feature of the cancer-free trichothiodystrophy. Proc Natl Acad Sci U S A 2021; 118:2024502118. [PMID: 34155103 DOI: 10.1073/pnas.2024502118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The cancer-free photosensitive trichothiodystrophy (PS-TTD) and the cancer-prone xeroderma pigmentosum (XP) are rare monogenic disorders that can arise from mutations in the same genes, namely ERCC2/XPD or ERCC3/XPB Both XPD and XPB proteins belong to the 10-subunit complex transcription factor IIH (TFIIH) that plays a key role in transcription and nucleotide excision repair, the DNA repair pathway devoted to the removal of ultraviolet-induced DNA lesions. Compelling evidence suggests that mutations affecting the DNA repair activity of TFIIH are responsible for the pathological features of XP, whereas those also impairing transcription give rise to TTD. By adopting a relatives-based whole transcriptome sequencing approach followed by specific gene expression profiling in primary fibroblasts from a large cohort of TTD or XP cases with mutations in ERCC2/XPD gene, we identify the expression alterations specific for TTD primary dermal fibroblasts. While most of these transcription deregulations do not impact on the protein level, very low amounts of prostaglandin I2 synthase (PTGIS) are found in TTD cells. PTGIS catalyzes the last step of prostaglandin I2 synthesis, a potent vasodilator and inhibitor of platelet aggregation. Its reduction characterizes all TTD cases so far investigated, both the PS-TTD with mutations in TFIIH coding genes as well as the nonphotosensitive (NPS)-TTD. A severe impairment of TFIIH and RNA polymerase II recruitment on the PTGIS promoter is found in TTD but not in XP cells. Thus, PTGIS represents a biomarker that combines all PS- and NPS-TTD cases and distinguishes them from XP.
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Compe E, Egly JM. The Long Road to Understanding RNAPII Transcription Initiation and Related Syndromes. Annu Rev Biochem 2021; 90:193-219. [PMID: 34153211 DOI: 10.1146/annurev-biochem-090220-112253] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In eukaryotes, transcription of protein-coding genes requires the assembly at core promoters of a large preinitiation machinery containing RNA polymerase II (RNAPII) and general transcription factors (GTFs). Transcription is potentiated by regulatory elements called enhancers, which are recognized by specific DNA-binding transcription factors that recruit cofactors and convey, following chromatin remodeling, the activating cues to the preinitiation complex. This review summarizes nearly five decades of work on transcription initiation by describing the sequential recruitment of diverse molecular players including the GTFs, the Mediator complex, and DNA repair factors that support RNAPII to enable RNA synthesis. The elucidation of the transcription initiation mechanism has greatly benefited from the study of altered transcription components associated with human diseases that could be considered transcription syndromes.
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Affiliation(s)
- Emmanuel Compe
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, 67404 Illkirch CEDEX, Commune Urbaine de Strasbourg, France; ,
| | - Jean-Marc Egly
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, 67404 Illkirch CEDEX, Commune Urbaine de Strasbourg, France; , .,College of Medicine, National Taiwan University, Taipei 10051, Taiwan
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13
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He Y, Tao W, Shang C, Qi C, Ji D, Lu W, Chen G. Xeroderma Pigmentosum group D suppresses proliferation and promotes apoptosis of HepG2 cells by downregulating ERG expression via the PPARγ pathway. Int J Exp Pathol 2021; 102:157-162. [PMID: 33993564 DOI: 10.1111/iep.12396] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 01/11/2021] [Accepted: 02/21/2021] [Indexed: 12/12/2022] Open
Abstract
Xeroderma Pigmentosum group D (XPD) gene has been shown to suppress hepatocellular carcinoma (HCC) progression, but its mechanism remains not fully understood. ETS-related gene (ERG) is generally known as an oncogenic gene. This study aimed to explore whether XPD regulated HCC cell proliferation, apoptosis and cell cycle by inhibiting ERG expression via the PPARγ pathway. The human hepatoma cells (HepG2) were transfected with the XPD overexpression vector (pEGFP-N2/XPD) or empty vector (pEGFP-N2). The PPARγ inhibitor GW9662 was used to determine whether XPD effects were mediated by activation of PPARγ pathway. Cell cycle and apoptosis were ascertained by flow cytometry, and cell viability was measured by MTT assay. Reverse transcription-polymerase chain reaction and Western blot were performed to determine the mRNA and protein levels. Overexpression of XPD significantly enhanced the expression of PPARγ and p-PPARγ, whereas it downregulated that of ERG and cdk7. Furthermore, XPD overexpression notably inhibited proliferation, promoted apoptosis and decreased the percentage of cells in the S + G2 phase of HepG2 cells. However, these effects of XPD overexpression were abrogated by GW9662. Collectively, XPD suppresses proliferation and promotes apoptosis of HepG2 cells by downregulating ERG expression via activation of the PPARγ pathway.
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Affiliation(s)
- Yue He
- Department of Hematology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Wenqiang Tao
- Department of ICU, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Chao Shang
- Administration Center, Jiangxi Electric Power Research Institute, Nanchang, China
| | - Chan Qi
- Department of emergency, The First hospital of Nanchang city, Nanchang, China
| | - Dexiang Ji
- Department of Hematology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Wei Lu
- Department of Hematology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Guoan Chen
- Department of Hematology, The First Affiliated Hospital of Nanchang University, Nanchang, China
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Okuda M, Ekimoto T, Kurita JI, Ikeguchi M, Nishimura Y. Structural and dynamical insights into the PH domain of p62 in human TFIIH. Nucleic Acids Res 2021; 49:2916-2930. [PMID: 33211877 PMCID: PMC7969019 DOI: 10.1093/nar/gkaa1045] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 09/30/2020] [Accepted: 10/22/2020] [Indexed: 11/15/2022] Open
Abstract
TFIIH is a crucial transcription and DNA repair factor consisting of the seven-subunit core. The core subunit p62 contains a pleckstrin homology domain (PH-D), which is essential for locating TFIIH at transcription initiation and DNA damage sites, and two BSD (BTF2-like transcription factors, synapse-associated proteins and DOS2-like proteins) domains. A recent cryo-electron microscopy (cryo-EM) structure of human TFIIH visualized most parts of core, except for the PH-D. Here, by nuclear magnetic resonance spectroscopy we have established the solution structure of human p62 PH-D connected to the BSD1 domain by a highly flexible linker, suggesting the flexibility of PH-D in TFIIH. Based on this dynamic character, the PH-D was modeled in the cryo-EM structure to obtain the whole human TFIIH core structure, which indicates that the PH-D moves around the surface of core with a specific but limited spatial distribution; these dynamic structures were refined by molecular dynamics (MD) simulations. Furthermore, we built models, also refined by MD simulations, of TFIIH in complex with five p62-binding partners, including transcription factors TFIIEα, p53 and DP1, and nucleotide excision repair factors XPC and UVSSA. The models explain why the PH-D is crucially targeted by these factors, which use their intrinsically disordered acidic regions for TFIIH recruitment.
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Affiliation(s)
- Masahiko Okuda
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Toru Ekimoto
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Jun-Ichi Kurita
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Mitsunori Ikeguchi
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.,RIKEN Medical Sciences Innovation Hub Program, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Yoshifumi Nishimura
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.,Graduate School of Integrated Sciences for Life, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima 739-8258, Japan
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15
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Cardiolipin-mediated PPARγ S112 phosphorylation impairs IL-10 production and inflammation resolution during bacterial pneumonia. Cell Rep 2021; 34:108736. [PMID: 33567272 PMCID: PMC7947928 DOI: 10.1016/j.celrep.2021.108736] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 12/17/2020] [Accepted: 01/20/2021] [Indexed: 12/20/2022] Open
Abstract
Bacterial pneumonia is a global healthcare burden, and unwarranted inflammation is suggested as an important cause of mortality. Optimum levels of the anti-inflammatory cytokine IL-10 are essential to reduce inflammation and improve survival in pneumonia. Elevated levels of the mitochondrial-DAMP cardiolipin (CL), reported in tracheal aspirates of pneumonia patients, have been shown to block IL-10 production from lung MDSCs. Although CL-mediated K107 SUMOylation of PPARγ has been suggested to impair this IL-10 production, the mechanism remains elusive. We identify PIAS2 to be the specific E3-SUMOligase responsible for this SUMOylation. Moreover, we identify a concomitant CL-mediated PPARγ S112 phosphorylation, mediated by JNK-MAPK, to be essential for PIAS2 recruitment. Furthermore, using a clinically tested peptide inhibitor targeting JNK-MAPK, we blocked these post-translational modifications (PTMs) of PPARγ and rescued IL-10 expression, improving survival in murine pneumonia models. Thus, we explore the mechanism of mito-DAMP-mediated impaired lung inflammation resolution and propose a therapeutic strategy targeting PPARγ PTMs.
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16
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Abstract
Cyclin-dependent kinase 7 (CDK7), along with cyclin H and MAT1, forms the CDK-activating complex (CAK), which directs progression through the cell cycle via T-loop phosphorylation of cell cycle CDKs. CAK is also a component of the general transcription factor, TFIIH. CDK7-mediated phosphorylation of RNA polymerase II (Pol II) at active gene promoters permits transcription. Cell cycle dysregulation is an established hallmark of cancer, and aberrant control of transcriptional processes, through diverse mechanisms, is also common in many cancers. Furthermore, CDK7 levels are elevated in a number of cancer types and are associated with clinical outcomes, suggestive of greater dependence on CDK7 activity, compared with normal tissues. These findings identify CDK7 as a cancer therapeutic target, and several recent publications report selective CDK7 inhibitors (CDK7i) with activity against diverse cancer types. Preclinical studies have shown that CDK7i cause cell cycle arrest, apoptosis and repression of transcription, particularly of super-enhancer-associated genes in cancer, and have demonstrated their potential for overcoming resistance to cancer treatments. Moreover, combinations of CDK7i with other targeted cancer therapies, including BET inhibitors, BCL2 inhibitors and hormone therapies, have shown efficacy in model systems. Four CDK7i, ICEC0942 (CT7001), SY-1365, SY-5609 and LY3405105, have now progressed to Phase I/II clinical trials. Here we describe the work that has led to the development of selective CDK7i, the current status of the most advanced clinical candidates, and discuss their potential importance as cancer therapeutics, both as monotherapies and in combination settings. ClinicalTrials.gov Identifiers: NCT03363893; NCT03134638; NCT04247126; NCT03770494.
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17
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Dias MMG, Batista FAH, Tittanegro TH, de Oliveira AG, Le Maire A, Torres FR, Filho HVR, Silveira LR, Figueira ACM. PPARγ S273 Phosphorylation Modifies the Dynamics of Coregulator Proteins Recruitment. Front Endocrinol (Lausanne) 2020; 11:561256. [PMID: 33329381 PMCID: PMC7729135 DOI: 10.3389/fendo.2020.561256] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 10/20/2020] [Indexed: 11/24/2022] Open
Abstract
The nuclear receptor PPARγ is essential to maintain whole-body glucose homeostasis and insulin sensitivity, acting as a master regulator of adipogenesis, lipid, and glucose metabolism. Its activation through natural or synthetic ligands induces the recruitment of coactivators, leading to transcription of target genes such as cytokines and hormones. More recently, post translational modifications, such as PPARγ phosphorylation at Ser273 by CDK5 in adipose tissue, have been linked to insulin resistance trough the dysregulation of expression of a specific subset of genes. Here, we investigate how this phosphorylation may disturb the interaction between PPARγ and some coregulator proteins as a new mechanism that may leads to insulin resistance. Through cellular and in vitro assays, we show that PPARγ phosphorylation inhibition increased the activation of the receptor, therefore the increased recruitment of PGC1-α and TIF2 coactivators, whilst decreases the interaction with SMRT and NCoR corepressors. Moreover, our results show a shift in the coregulators interaction domains preferences, suggesting additional interaction interfaces formed between the phosphorylated PPARγ and some coregulator proteins. Also, we observed that the CDK5 presence disturb the PPARγ-coregulator's synergy, decreasing interaction with PGC1-α, TIF2, and NCoR, but increasing coupling of SMRT. Finally, we conclude that the insulin resistance provoked by PPARγ phosphorylation is linked to a differential coregulators recruitment, which may promote dysregulation in gene expression.
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Affiliation(s)
- Marieli Mariano Gonçalves Dias
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
- Graduate Program in Functional and Molecular Biology, Institute of Biology, State University of Campinas (Unicamp), Campinas, Brazil
| | | | - Thais Helena Tittanegro
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
| | - André Gustavo de Oliveira
- Mitochondrial Molecular Biology Laboratory, Obesity and Comorbidities Research Center (OCRC), Campinas, Brazil
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Albane Le Maire
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
- Centre de Biochimie Structurale CNRS, Université de Montpellier, Montpellier, France
| | - Felipe Rafael Torres
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
| | - Helder Veras Ribeiro Filho
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
| | - Leonardo Reis Silveira
- Mitochondrial Molecular Biology Laboratory, Obesity and Comorbidities Research Center (OCRC), Campinas, Brazil
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Ana Carolina Migliorini Figueira
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
- Graduate Program in Functional and Molecular Biology, Institute of Biology, State University of Campinas (Unicamp), Campinas, Brazil
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18
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Hsiao WY, Jung SM, Tang Y, Haley JA, Li R, Li H, Calejman CM, Sanchez-Gurmaches J, Hung CM, Luciano AK, DeMambro V, Wellen KE, Rosen CJ, Zhu LJ, Guertin DA. The Lipid Handling Capacity of Subcutaneous Fat Is Programmed by mTORC2 during Development. Cell Rep 2020; 33:108223. [PMID: 33027655 PMCID: PMC7607535 DOI: 10.1016/j.celrep.2020.108223] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 08/12/2020] [Accepted: 09/11/2020] [Indexed: 02/08/2023] Open
Abstract
Overweight and obesity are associated with type 2 diabetes, non-alcoholic fatty liver disease, cardiovascular disease and cancer, but all fat is not equal, as storing excess lipid in subcutaneous white adipose tissue (SWAT) is more metabolically favorable than in visceral fat. Here, we uncover a critical role for mTORC2 in setting SWAT lipid handling capacity. We find that subcutaneous white preadipocytes differentiating without the essential mTORC2 subunit Rictor upregulate mature adipocyte markers but develop a striking lipid storage defect resulting in smaller adipocytes, reduced tissue size, lipid re-distribution to visceral and brown fat, and sex-distinct effects on systemic metabolic fitness. Mechanistically, mTORC2 promotes transcriptional upregulation of select lipid metabolism genes controlled by PPARγ and ChREBP, including genes that control lipid uptake, synthesis, and degradation pathways as well as Akt2, which encodes a major mTORC2 substrate and insulin effector. Further exploring this pathway may uncover new strategies to improve insulin sensitivity.
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Affiliation(s)
- Wen-Yu Hsiao
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Su Myung Jung
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Yuefeng Tang
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - John A. Haley
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Rui Li
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Huawei Li
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Camila Martinez Calejman
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Joan Sanchez-Gurmaches
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA,Division of Endocrinology, Developmental Biology, Cincinnati Children’s Hospital Research Foundation, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Chien-Min Hung
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Amelia K. Luciano
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | | | - Kathryn E. Wellen
- Center for Clinical and Translational Research, Maine Medical Center, Scarborough, MN 04074, USA,Department of Cancer Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Clifford J. Rosen
- Center for Clinical and Translational Research, Maine Medical Center, Scarborough, MN 04074, USA
| | - Lihua Julie Zhu
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA,Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA,Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - David A. Guertin
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA,Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA,Lead Contact,Correspondence:
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19
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Khim KW, Choi SS, Jang HJ, Lee YH, Lee E, Hyun JM, Eom HJ, Yoon S, Choi JW, Park TE, Nam D, Choi JH. PPM1A Controls Diabetic Gene Programming through Directly Dephosphorylating PPARγ at Ser273. Cells 2020; 9:cells9020343. [PMID: 32024237 PMCID: PMC7072254 DOI: 10.3390/cells9020343] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 01/31/2020] [Indexed: 12/16/2022] Open
Abstract
Peroxisome proliferator-activated receptor γ (PPARγ) is a master regulator of adipose tissue biology. In obesity, phosphorylation of PPARγ at Ser273 (pSer273) by cyclin-dependent kinase 5 (CDK5)/extracellular signal-regulated kinase (ERK) orchestrates diabetic gene reprogramming via dysregulation of specific gene expression. Although many recent studies have focused on the development of non-classical agonist drugs that inhibit the phosphorylation of PPARγ at Ser273, the molecular mechanism of PPARγ dephosphorylation at Ser273 is not well characterized. Here, we report that protein phosphatase Mg2+/Mn2+-dependent 1A (PPM1A) is a novel PPARγ phosphatase that directly dephosphorylates Ser273 and restores diabetic gene expression which is dysregulated by pSer273. The expression of PPM1A significantly decreases in two models of insulin resistance: diet-induced obese (DIO) mice and db/db mice, in which it negatively correlates with pSer273. Transcriptomic analysis using microarray and genotype-tissue expression (GTEx) data in humans shows positive correlations between PPM1A and most of the genes that are dysregulated by pSer273. These findings suggest that PPM1A dephosphorylates PPARγ at Ser273 and represents a potential target for the treatment of obesity-linked metabolic disorders.
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20
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Hashimoto S, Takanari H, Compe E, Egly JM. Dysregulation of LXR responsive genes contribute to ichthyosis in trichothiodystrophy. J Dermatol Sci 2020; 97:201-207. [PMID: 32037099 DOI: 10.1016/j.jdermsci.2020.01.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 12/29/2019] [Accepted: 01/21/2020] [Indexed: 02/01/2023]
Abstract
BACKGROUND Trichothiodystrophy (TTD) is a rare autosomal recessive disorder characterised by brittle hairs and various systemic symptoms, including photosensitivity and ichthyosis. While photosensitivity could result from DNA repair defects, other TTD clinical features might be due to deficiencies in certain molecular processes. OBJECTIVES The aim of this study was to understand the pathophysiological mechanism of ichthyosis in TTD, focused on the transcriptional dysregulation. METHODS TTD mouse skin tissue and keratinocytes were pathologically and physiologically examined to identify the alteration of lipid homeostasis in TTD with ichtyosis. Gene expression of certain lipid transporter was assessed in fibroblasts derived from TTD patients and TTD mouse keratinocytes. RESULTS Histopathology and electron microscopy revealed abnormal lipid composition in TTD mice skin. In addition to abnormal cholesterol dynamics, TTD mouse keratinocytes exhibit impaired expression of Liver X receptor (LXR) responsive genes, including Abca12, a key regulator of Harlequin ichthyosis, and Abcg1 that is involved in the cholesterol transport process in the epidermis. Strikingly, dysregulation of LXR responsive genes has been only observed in cells isolated from TTD patients who developed ichthyosis. CONCLUSIONS Our results suggest that the altered expression of the LXR-responsive genes contribute to the pathophysiology of ichthyosis in TTD. These findings provide a new drug discovery target for TTD.
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Affiliation(s)
- Satoru Hashimoto
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/Université de Strasbourg, Strasbourg, France; Clinical Research Center for Diabetes, Tokushima University Hospital, Tokushima, Japan; Department of Genetics, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.
| | - Hiroki Takanari
- Clinical Research Center for Diabetes, Tokushima University Hospital, Tokushima, Japan; Department of Interdisciplinary Researches for Medicine and Photonics, Institute of Post-LED Photonics, Tokushima, Japan
| | - Emmanuel Compe
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/Université de Strasbourg, Strasbourg, France
| | - Jean-Marc Egly
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/Université de Strasbourg, Strasbourg, France.
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21
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Filatov MA, Nikishin DA, Khramova YV, Semenova ML. The in vitro Analysis of Quality of Ovarian Follicle Culture Systems Using Time-Lapse Microscopy and Quantitative Real-Time PCR. J Reprod Infertil 2020; 21:94-106. [PMID: 32500012 PMCID: PMC7253941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND The aim of ovarian follicle in vitro culture is to obtain mature oocytes. To evaluate the efficiency of in vitro culture system, the status of the cultured oocyte can be analyzed. METHODS The preantral ovarian follicles retrieved from 14-day-old C57Bl/6J mice were cultured in 3D alginate hydrogel. The status of oocytes obtained from mature (3 months old, group A) and immature (3 weeks old, group B) mice was compared to the status of oocytes retrieved from ovarian follicles cultured in vitro (Group C) using qRT-PCR analysis and time-lapse microscopy. In the qRT-PCR analysis, 8 samples for group A (80 oocytes), 8 samples for group B (80 oocytes), and 6 samples for group C (60 oocytes) were included. Time-lapse analysis was performed in group A (oocytes n=31), group B (n=45), and group C (n=21). Statistical analysis was done by Kruskal-Wallis and chi-square tests and differences were considered statistically significant if p<0,05. RESULTS The diameter of group C oocytes is lower in comparison to group A oocytes (67 μm vs. 75 μm, correspondingly). Groups B and C oocytes exhibited delayed meiosis in comparison to group A oocytes. Expression levels of six oocyte maturation genes (Ccnb, CDK1, Ccnh, Wee2, Mos and Epab) were evaluated using qRT-PCR analysis. Expression levels of Ccnh and Epab are lowered in group C oocytes compared to the expression levels of these genes in groups A and B oocytes (p< 0.05). CONCLUSION Oocytes obtained after ovarian follicles in vitro culture have reduced development competence, future fundamental changes of in vitro culture systems can be expected.
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Affiliation(s)
- Maxim Alexeevich Filatov
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia,Corresponding Author: Maxim Alexeevich Filatov, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia E-mail:
| | - Denis Alexandrovich Nikishin
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia, N.K. Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia
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22
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Metformin induces lipogenic differentiation in myofibroblasts to reverse lung fibrosis. Nat Commun 2019; 10:2987. [PMID: 31278260 PMCID: PMC6611870 DOI: 10.1038/s41467-019-10839-0] [Citation(s) in RCA: 171] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 06/03/2019] [Indexed: 01/05/2023] Open
Abstract
Idiopathic pulmonary fibrosis (IPF) is a fatal disease in which the intricate alveolar network of the lung is progressively replaced by fibrotic scars. Myofibroblasts are the effector cells that excessively deposit extracellular matrix proteins thus compromising lung structure and function. Emerging literature suggests a correlation between fibrosis and metabolic alterations in IPF. In this study, we show that the first-line antidiabetic drug metformin exerts potent antifibrotic effects in the lung by modulating metabolic pathways, inhibiting TGFβ1 action, suppressing collagen formation, activating PPARγ signaling and inducing lipogenic differentiation in lung fibroblasts derived from IPF patients. Using genetic lineage tracing in a murine model of lung fibrosis, we show that metformin alters the fate of myofibroblasts and accelerates fibrosis resolution by inducing myofibroblast-to-lipofibroblast transdifferentiation. Detailed pathway analysis revealed a two-arm mechanism by which metformin accelerates fibrosis resolution. Our data report an antifibrotic role for metformin in the lung, thus warranting further therapeutic evaluation. Idiopathic pulmonary fibrosis is associated with myofibroblast activation in the lungs and metabolic alterations. Here, the authors show that the antidiabetic drug metformin has antifibrotic effects in human-derived samples and mouse models, by modulating a number of metabolic pathways to induce lipogenic transdifferentiation of myofibroblasts.
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23
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Ferri D, Orioli D, Botta E. Heterogeneity and overlaps in nucleotide excision repair disorders. Clin Genet 2019; 97:12-24. [PMID: 30919937 DOI: 10.1111/cge.13545] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 02/27/2019] [Accepted: 03/26/2019] [Indexed: 12/22/2022]
Abstract
Nucleotide excision repair (NER) is an essential DNA repair pathway devoted to the removal of bulky lesions such as photoproducts induced by the ultraviolet (UV) component of solar radiation. Deficiencies in NER typically result in a group of heterogeneous distinct disorders ranging from the mild UV sensitive syndrome to the cancer-prone xeroderma pigmentosum and the neurodevelopmental/progeroid conditions trichothiodystrophy, Cockayne syndrome and cerebro-oculo-facio-skeletal-syndrome. A complicated genetic scenario underlines these disorders with the same gene linked to different clinical entities as well as different genes associated with the same disease. Overlap syndromes with combined hallmark features of different NER disorders can occur and sporadic presentations showing extra features of the hematological disorder Fanconi Anemia or neurological manifestations mimicking Hungtinton disease-like syndromes have been described. Here, we discuss the multiple functions of the five major pleiotropic NER genes (ERCC3/XPB, ERCC2/XPD, ERCC5/XPG, ERCC1 and ERCC4/XPF) and their relevance in phenotypic complexity. We provide an update of mutational spectra and examine genotype-phenotype relationships. Finally, the molecular defects that could explain the puzzling overlap syndromes are discussed.
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Affiliation(s)
- Debora Ferri
- Istituto di Genetica Molecolare (IGM), Consiglio Nazionale delle Ricerche, Pavia, Italy
| | - Donata Orioli
- Istituto di Genetica Molecolare (IGM), Consiglio Nazionale delle Ricerche, Pavia, Italy
| | - Elena Botta
- Istituto di Genetica Molecolare (IGM), Consiglio Nazionale delle Ricerche, Pavia, Italy
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24
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Kolesnikova O, Radu L, Poterszman A. TFIIH: A multi-subunit complex at the cross-roads of transcription and DNA repair. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2019; 115:21-67. [PMID: 30798933 DOI: 10.1016/bs.apcsb.2019.01.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Transcription factor IIH (TFIIH) is a multiprotein complex involved in both eukaryotic transcription and DNA repair, revealing a tight connection between these two processes. Composed of 10 subunits, it can be resolved into a 7-subunits core complex with the XPB translocase and the XPD helicase, and the 3-subunits kinase complex CAK, which also exists as a free complex with a distinct function. Initially identified as basal transcription factor, TFIIH also participates in transcription regulation and plays a key role in nucleotide excision repair (NER) for opening DNA at damaged sites, lesion verification and recruitment of additional repair factors. Our understanding of TFIIH function in eukaryotic cells has greatly benefited from studies of the genetic rare diseases xeroderma pigmentosum (XP), Cockayne syndrome (CS) and trichothiodystrophy (TTD), that are not only characterized by cancer and aging predispositions but also by neurological and developmental defects. Although much remains unknown about TFIIH function, significant progresses have been done regarding the structure of the complex, the functions of its catalytic subunits and the multiple roles of the regulatory core-TFIIH subunits. This review provides a non-exhaustive survey of key discoveries on the structure and function of this pivotal factor, which can be considered as a promising target for therapeutic strategies.
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Affiliation(s)
- Olga Kolesnikova
- Institut de Génétique et de Biologie Moléculaire et Cellulaire Illkirch Cedex, C.U. Strasbourg, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; Université de Strasbourg, Illkirch, France
| | - Laura Radu
- Institut de Génétique et de Biologie Moléculaire et Cellulaire Illkirch Cedex, C.U. Strasbourg, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; Université de Strasbourg, Illkirch, France
| | - Arnaud Poterszman
- Institut de Génétique et de Biologie Moléculaire et Cellulaire Illkirch Cedex, C.U. Strasbourg, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; Université de Strasbourg, Illkirch, France.
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25
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Abstract
Peroxisome proliferator-activated receptor γ (PPARγ) is a member of the nuclear receptor family and plays an important role in adipocyte differentiation, glucose homeostasis, and insulin sensitivity. Thiazolidinediones (TZDs), synthetic ligands of PPARγ, have been used for the treatment of diabetes mellitus for two decades. TZDs were expected to be amazing drugs not only for type 2 diabetes but also for metabolic syndrome and atherosclerotic vascular disease because they can reduce both insulin resistance and inflammation in experimental studies. However, serious unwanted effects pushed TZDs back to an optional second-tier drug for type 2 diabetes. Nevertheless, PPARγ is still one of the most important targets for the treatment of insulin resistance and diabetes mellitus, and novel strategies to modulate PPARγ activity to enhance its beneficial effects and reduce unwanted adverse effects are anticipated. Recent studies showed that post-translational modification (PTM) of PPARγ regulates PPARγ activity or stability and may be a novel way to optimize PPARγ activity with reduced adverse effects. In this review, we will focus on recent advances in PTM of PPARγ and the mechanisms regulating PPARγ function as well as in the development of PPARγ modulators or agonists.
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Affiliation(s)
- Sung Hee Choi
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea.,Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea
| | - Sung Soo Chung
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea
| | - Kyong Soo Park
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea.,Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, South Korea
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26
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Functional Regulation of PPARs through Post-Translational Modifications. Int J Mol Sci 2018; 19:ijms19061738. [PMID: 29895749 PMCID: PMC6032173 DOI: 10.3390/ijms19061738] [Citation(s) in RCA: 150] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/05/2018] [Accepted: 06/07/2018] [Indexed: 12/11/2022] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs) belong to the nuclear receptor superfamily and they are essential regulators of cell differentiation, tissue development, and energy metabolism. Given their central roles in sensing the cellular metabolic state and controlling metabolic homeostasis, PPARs became important targets of drug development for the management of metabolic disorders. The function of PPARs is mainly regulated through ligand binding, which induces structural changes, further affecting the interactions with co-activators or co-repressors to stimulate or inhibit their functions. In addition, PPAR functions are also regulated by various Post-translational modifications (PTMs). These PTMs include phosphorylation, SUMOylation, ubiquitination, acetylation, and O-GlcNAcylation, which are found at numerous modification sites. The addition of these PTMs has a wide spectrum of consequences on protein stability, transactivation function, and co-factor interaction. Moreover, certain PTMs in PPAR proteins have been associated with the status of metabolic diseases. In this review, we summarize the PTMs found on the three PPAR isoforms PPARα, PPARβ/δ, and PPARγ, and their corresponding modifying enzymes. We also discuss the functional roles of these PTMs in regulating metabolic homeostasis and provide a perspective for future research in this intriguing field.
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Cai W, Yang T, Liu H, Han L, Zhang K, Hu X, Zhang X, Yin KJ, Gao Y, Bennett MVL, Leak RK, Chen J. Peroxisome proliferator-activated receptor γ (PPARγ): A master gatekeeper in CNS injury and repair. Prog Neurobiol 2017; 163-164:27-58. [PMID: 29032144 DOI: 10.1016/j.pneurobio.2017.10.002] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 10/06/2017] [Accepted: 10/08/2017] [Indexed: 01/06/2023]
Abstract
Peroxisome proliferator-activated receptor γ (PPARγ) is a widely expressed ligand-modulated transcription factor that governs the expression of genes involved in inflammation, redox equilibrium, trophic factor production, insulin sensitivity, and the metabolism of lipids and glucose. Synthetic PPARγ agonists (e.g. thiazolidinediones) are used to treat Type II diabetes and have the potential to limit the risk of developing brain injuries such as stroke by mitigating the influence of comorbidities. If brain injury develops, PPARγ serves as a master gatekeeper of cytoprotective stress responses, improving the chances of cellular survival and recovery of homeostatic equilibrium. In the acute injury phase, PPARγ directly restricts tissue damage by inhibiting the NFκB pathway to mitigate inflammation and stimulating the Nrf2/ARE axis to neutralize oxidative stress. During the chronic phase of acute brain injuries, PPARγ activation in injured cells culminates in the repair of gray and white matter, preservation of the blood-brain barrier, reconstruction of the neurovascular unit, resolution of inflammation, and long-term functional recovery. Thus, PPARγ lies at the apex of cell fate decisions and exerts profound effects on the chronic progression of acute injury conditions. Here, we review the therapeutic potential of PPARγ in stroke and brain trauma and highlight the novel role of PPARγ in long-term tissue repair. We describe its structure and function and identify the genes that it targets. PPARγ regulation of inflammation, metabolism, cell fate (proliferation/differentiation/maturation/survival), and many other processes also has relevance to other neurological diseases. Therefore, PPARγ is an attractive target for therapies against a number of progressive neurological disorders.
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Affiliation(s)
- Wei Cai
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Tuo Yang
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Huan Liu
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Lijuan Han
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Kai Zhang
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Xiaoming Hu
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA; State Key Laboratory of Medical Neurobiology and Institutes of Brain Science, Fudan University, Shanghai 200032, China; Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh PA, USA
| | - Xuejing Zhang
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Ke-Jie Yin
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Yanqin Gao
- State Key Laboratory of Medical Neurobiology and Institutes of Brain Science, Fudan University, Shanghai 200032, China
| | - Michael V L Bennett
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Rehana K Leak
- Division of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, Pittsburgh, PA 15282, USA.
| | - Jun Chen
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA; State Key Laboratory of Medical Neurobiology and Institutes of Brain Science, Fudan University, Shanghai 200032, China; Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh PA, USA.
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Zolezzi JM, Santos MJ, Bastías-Candia S, Pinto C, Godoy JA, Inestrosa NC. PPARs in the central nervous system: roles in neurodegeneration and neuroinflammation. Biol Rev Camb Philos Soc 2017; 92:2046-2069. [PMID: 28220655 DOI: 10.1111/brv.12320] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 12/21/2016] [Accepted: 01/11/2017] [Indexed: 12/20/2022]
Abstract
Over 25 years have passed since peroxisome proliferators-activated receptors (PPARs), were first described. Like other members of the nuclear receptors superfamily, PPARs have been defined as critical sensors and master regulators of cellular metabolism. Recognized as ligand-activated transcription factors, they are involved in lipid, glucose and amino acid metabolism, taking part in different cellular processes, including cellular differentiation and apoptosis, inflammatory modulation and attenuation of acute and chronic neurological damage in vivo and in vitro. Interestingly, PPAR activation can simultaneously reprogram the immune response, stimulate metabolic and mitochondrial functions, promote axonal growth, induce progenitor cells to differentiate into myelinating oligodendrocytes, and improve brain clearance of toxic molecules such as β-amyloid peptide. Although the molecular mechanisms and cross-talk with different molecular pathways are still the focus of intense research, PPARs are considered potential therapeutic targets for several neuropathological conditions, including degenerative disorders such as Alzheimer's, Parkinson's and Huntington's disease. This review considers recent advances regarding PPARs, as well as new PPAR agonists. We focus on the mechanisms behind the neuroprotective effects exerted by PPARs and summarise the roles of PPARs in different pathologies of the central nervous system, especially those associated with degenerative and inflammatory mechanisms.
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Affiliation(s)
- Juan M Zolezzi
- Centro de Envejecimiento y Regeneración (CARE-UC), P. Catholic University of Chile, PO Box 114-D, 8331150, Santiago, Chile
| | - Manuel J Santos
- Facultad de Ciencias Biológicas, Departamento de Biología Celular y Molecular, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile
| | - Sussy Bastías-Candia
- Facultad de Ciencias, Departamento de Biología, Universidad de Tarapacá, Gral. Velásquez 1775, 1000007, Arica, Chile
| | - Claudio Pinto
- Centro de Envejecimiento y Regeneración (CARE-UC), P. Catholic University of Chile, PO Box 114-D, 8331150, Santiago, Chile
| | - Juan A Godoy
- Centro de Envejecimiento y Regeneración (CARE-UC), P. Catholic University of Chile, PO Box 114-D, 8331150, Santiago, Chile.,Facultad de Ciencias Biológicas, Departamento de Biología Celular y Molecular, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile
| | - Nibaldo C Inestrosa
- Centro de Envejecimiento y Regeneración (CARE-UC), P. Catholic University of Chile, PO Box 114-D, 8331150, Santiago, Chile.,Facultad de Ciencias Biológicas, Departamento de Biología Celular y Molecular, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile.,Faculty of Medicine, Centre for Healthy Brain Ageing, School of Psychiatry, University of New South Wales, Avoca Street Randwick NSW 2031, Sydney, Australia.,Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, PO Box 113-D, Avenida Bulnes 01855, 6210427, Punta Arenas, Chile
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29
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Downing LE, Edgar D, Ellison PA, Ricketts ML. Mechanistic insight into nuclear receptor-mediated regulation of bile acid metabolism and lipid homeostasis by grape seed procyanidin extract (GSPE). Cell Biochem Funct 2017; 35:12-32. [DOI: 10.1002/cbf.3247] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 12/13/2016] [Accepted: 12/16/2016] [Indexed: 12/18/2022]
Affiliation(s)
- Laura E. Downing
- Department of Agriculture, Nutrition and Veterinary Sciences; University of Nevada Reno; Reno Nevada USA
| | - Daniel Edgar
- Department of Biochemistry and Molecular Biology; University of Nevada Reno; Reno Nevada USA
| | - Patricia A. Ellison
- Department of Biochemistry and Molecular Biology; University of Nevada Reno; Reno Nevada USA
| | - Marie-Louise Ricketts
- Department of Agriculture, Nutrition and Veterinary Sciences; University of Nevada Reno; Reno Nevada USA
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30
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Okuda M, Araki K, Ohtani K, Nishimura Y. The Interaction Mode of the Acidic Region of the Cell Cycle Transcription Factor DP1 with TFIIH. J Mol Biol 2016; 428:4993-5006. [DOI: 10.1016/j.jmb.2016.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 10/27/2016] [Accepted: 11/01/2016] [Indexed: 10/20/2022]
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31
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Shu Y, Lu Y, Pang X, Zheng W, Huang Y, Li J, Ji J, Zhang C, Shen P. Phosphorylation of PPARγ at Ser84 promotes glycolysis and cell proliferation in hepatocellular carcinoma by targeting PFKFB4. Oncotarget 2016; 7:76984-76994. [PMID: 27769068 PMCID: PMC5363564 DOI: 10.18632/oncotarget.12764] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 10/14/2016] [Indexed: 02/07/2023] Open
Abstract
Peroxisome proliferator-activating receptor γ (PPARγ), a transcription factor, is involved in many important biological processes, including cell terminal differentiation, survival and apoptosis. However, the role of PPARγ, which regulates tumour promoter and oncogene expression, is not well understood in hepatocellular carcinoma (HCC). In the present study, based on evidence from clinical samples that phosphorylation of PPARγ at Ser84 is up-regulated in human liver tumours, we confirmed that phosphorylation of PPARγ was also significantly increased in an HCC mouse model and was increased by Mitogen-activated protein kinase (MEK)/ Extracellular-signal-regulated kinases (ERK) kinase. Next, we performed an RNA microarray analysis, and our data indicated that dephosphorylation of PPARγ at Ser84 affects the expression of glycolysis-related genes and pro-proliferation genes, which supposedly promote proliferation of HCC cells. Using a chromatin immunoprecipitation (ChIP) assay, we demonstrated that the observed PPARγ-mediated induction of 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 4 (PFKFB4) expression was directly modulated by the transcriptional activity of its promoter. Furthermore, using knockdown of PFKFB4, we elucidated that the stimulation of PPARγ phosphorylation on glycolysis and proliferation in HCC is dependent on PFKFB4. Together, these findings extend our understanding of how liver tumour cells reprogram their glycolytic pathways by post-translational modification of specific transcription factors and lay a foundation for the screening of new targets for the treatment of HCC.
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Affiliation(s)
- Yuxin Shu
- State Key Laboratory of Pharmaceutical Biotechnology and Model Animal Research Center (MARC), Nanjing University, Nanjing 210023, China
| | - Yan Lu
- State Key Laboratory of Pharmaceutical Biotechnology and Model Animal Research Center (MARC), Nanjing University, Nanjing 210023, China
| | - Xiaojuan Pang
- State Key Laboratory of Pharmaceutical Biotechnology and Model Animal Research Center (MARC), Nanjing University, Nanjing 210023, China
| | - Wei Zheng
- State Key Laboratory of Pharmaceutical Biotechnology and Model Animal Research Center (MARC), Nanjing University, Nanjing 210023, China
| | - Yahong Huang
- State Key Laboratory of Pharmaceutical Biotechnology and Model Animal Research Center (MARC), Nanjing University, Nanjing 210023, China
| | - Jiahong Li
- State Key Laboratory of Pharmaceutical Biotechnology and Model Animal Research Center (MARC), Nanjing University, Nanjing 210023, China
| | - Jianguo Ji
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
- Institute of System Biomedicine, School of Basic Medical Sciences, Peking University, Beijing 100191, China
| | - Can Zhang
- Center of Drug Discovery, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, PR China
| | - Pingping Shen
- State Key Laboratory of Pharmaceutical Biotechnology and Model Animal Research Center (MARC), Nanjing University, Nanjing 210023, China
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32
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Stechschulte LA, Ge C, Hinds TD, Sanchez ER, Franceschi RT, Lecka-Czernik B. Protein Phosphatase PP5 Controls Bone Mass and the Negative Effects of Rosiglitazone on Bone through Reciprocal Regulation of PPARγ (Peroxisome Proliferator-activated Receptor γ) and RUNX2 (Runt-related Transcription Factor 2). J Biol Chem 2016; 291:24475-24486. [PMID: 27687725 PMCID: PMC5114402 DOI: 10.1074/jbc.m116.752493] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 09/28/2016] [Indexed: 11/06/2022] Open
Abstract
Peroxisome proliferator-activated receptor γ (PPARγ) and runt-related transcription factor 2 (RUNX2) are key regulators of mesenchymal stem cell (MSC) differentiation toward adipocytes and osteoblasts, respectively. Post-translational modifications of these factors determine their activities. Dephosphorylation of PPARγ at Ser-112 is required for its adipocytic activity, whereas phosphorylation of RUNX2 at serine 319 (Ser-319) promotes its osteoblastic activity. Here we show that protein phosphatase 5 (PP5) reciprocally regulates each receptor by targeting each serine. Mice deficient in PP5 phosphatase have increased osteoblast numbers and high bone formation, which results in high bone mass in the appendicular and axial skeleton. This is associated with a substantial decrease in lipid-containing marrow adipocytes. Indeed, in the absence of PP5 the MSC lineage allocation is skewed toward osteoblasts and away from lipid accumulating adipocytes, although an increase in beige adipocyte gene expression is observed. In the presence of rosiglitazone, PP5 translocates to the nucleus, binds to PPARγ and RUNX2, and dephosphorylates both factors, resulting in activation of PPARγ adipocytic and suppression of RUNX2 osteoblastic activities. Moreover, shRNA knockdown of PP5 results in cells refractory to rosiglitazone treatment. Lastly, mice deficient in PP5 are resistant to the negative effects of rosiglitazone on bone, which in wild type animals causes a 50% decrease in trabecular bone mass. In conclusion, PP5 is a unique phosphatase reciprocally regulating PPARγ and RUNX2 activities in marrow MSC.
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Affiliation(s)
- Lance A Stechschulte
- From the Department of Orthopaedic Surgery,; the Center for Diabetes and Endocrine Research, University of Toledo Health Science Campus, Toledo, Ohio 43614 and
| | - Chunxi Ge
- the Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, Michigan 48109
| | | | - Edwin R Sanchez
- the Center for Diabetes and Endocrine Research, University of Toledo Health Science Campus, Toledo, Ohio 43614 and; Physiology and Pharmacology, and
| | - Renny T Franceschi
- the Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, Michigan 48109
| | - Beata Lecka-Czernik
- From the Department of Orthopaedic Surgery,; the Center for Diabetes and Endocrine Research, University of Toledo Health Science Campus, Toledo, Ohio 43614 and; Physiology and Pharmacology, and.
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33
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Downing LE, Ferguson BS, Rodriguez K, Ricketts ML. A grape seed procyanidin extract inhibits HDAC activity leading to increased Pparα phosphorylation and target-gene expression. Mol Nutr Food Res 2016; 61. [PMID: 27624175 DOI: 10.1002/mnfr.201600347] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 08/30/2016] [Accepted: 09/08/2016] [Indexed: 12/13/2022]
Abstract
SCOPE Histone deacetylases (HDACs) have emerged as epigenetic regulators of risk factors associated with the metabolic syndrome (MetS), and certain botanical extracts have proven to be potent HDAC inhibitors. Understanding the role of dietary procyanidins in HDAC inhibition is important in exploring the therapeutic potential of natural products. METHODS C57BL/6 mice were gavaged with vehicle (water) or grape seed procyanidin extract (GSPE, 250 mg/kg) and terminated 14 h later. Liver and serum were harvested to assess the effect of GSPE on HDAC activity, histone acetylation, Pparα activity and target-gene expression, and serum lipid levels. RESULTS GSPE increased histone acetylation and decreased Class I HDAC activity in vivo, and dose-dependently inhibited recombinant HDAC2 and 3 activities in vitro. Accordingly, Pparα gene and phosphorylated protein expression were increased, as were target genes involved in fatty acid catabolism, suggesting increased Pparα activity. Serum fibroblast growth factor 21 (Fgf21) was elevated, and triglyceride levels were reduced by 28%. CONCLUSION GSPE regulates HDAC and Pparα activities to modulate lipid catabolism and reduce serum triglycerides in vivo.
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Affiliation(s)
- Laura E Downing
- Department of Agriculture, Nutrition and Veterinary Sciences, University of Nevada Reno, Reno, NV, USA
| | - Bradley S Ferguson
- Department of Agriculture, Nutrition and Veterinary Sciences, University of Nevada Reno, Reno, NV, USA
| | - Kelvin Rodriguez
- Department of Agriculture, Nutrition and Veterinary Sciences, University of Nevada Reno, Reno, NV, USA
| | - Marie-Louise Ricketts
- Department of Agriculture, Nutrition and Veterinary Sciences, University of Nevada Reno, Reno, NV, USA
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34
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KVANDOVÁ M, MAJZÚNOVÁ M, DOVINOVÁ I. The Role of PPARγ in Cardiovascular Diseases. Physiol Res 2016; 65:S343-S363. [DOI: 10.33549/physiolres.933439] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The peroxisome proliferator-activated receptors (PPAR) belong to the nuclear superfamily of ligand-activated transcription factors. PPARγ acts as a nutrient sensor that regulates several homeostatic functions. Its disruption can lead to vascular pathologies, disorders of fatty acid/lipid metabolism and insulin resistance. PPARγ can modulate several signaling pathways connected with blood pressure regulation. Firstly, it affects the insulin signaling pathway and endothelial dysfunction by modulation of expression and/or phosphorylation of signaling molecules through the PI3K/Akt/eNOS or MAPK/ET-1 pathways. Secondly, it can modulate gene expression of the renin- angiotensin system – cascade proteins, which potentially slow down the progression of atherosclerosis and hypertension. Thirdly, it can modulate oxidative stress response either directly through PPAR or indirectly through Nrf2 activation. In this context, activation and functioning of PPARγ is very important in the regulation of several disorders such as diabetes mellitus, hypertension and/or metabolic syndrome.
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Affiliation(s)
| | | | - I. DOVINOVÁ
- Institute of Normal and Pathological Physiology, Slovak Academy of Sciences, Bratislava, Slovakia
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35
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Yu JH, Song SJ, Kim A, Choi Y, Seok JW, Kim HJ, Lee YJ, Lee KS, Kim JW. Suppression of PPARγ-mediated monoacylglycerol O-acyltransferase 1 expression ameliorates alcoholic hepatic steatosis. Sci Rep 2016; 6:29352. [PMID: 27404390 PMCID: PMC4941543 DOI: 10.1038/srep29352] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 06/16/2016] [Indexed: 12/20/2022] Open
Abstract
Alcohol consumption is one of the major causes of hepatic steatosis, fibrosis, cirrhosis, and superimposed hepatocellular carcinoma. Ethanol metabolism alters the NAD(+)/NADH ratio, thereby suppressing the activity of sirtuin family proteins, which may affect lipid metabolism in liver cells. However, it is not clear how long-term ingestion of ethanol eventually causes lipid accumulation in liver. Here, we demonstrate that chronic ethanol ingestion activates peroxisome proliferator-activated receptor γ (PPARγ) and its target gene, monoacylglycerol O-acyltransferase 1 (MGAT1). During ethanol metabolism, a low NAD(+)/NADH ratio repressed NAD-dependent deacetylase sirtuin 1 (SIRT1) activity, concomitantly resulting in increased acetylated PPARγ with high transcriptional activity. Accordingly, SIRT1 transgenic mice exhibited a low level of acetylated PPARγ and were protected from hepatic steatosis driven by alcohol or PPARγ2 overexpression, suggesting that ethanol metabolism causes lipid accumulation through activation of PPARγ through acetylation. Among the genes induced by PPARγ upon alcohol consumption, MGAT1 has been shown to be involved in triglyceride synthesis. Thus, we tested the effect of MGAT1 knockdown in mice following ethanol consumption, and found a significant reduction in alcohol-induced hepatic lipid accumulation. These results suggest that MGAT1 may afford a promising approach to the treatment of fatty liver disease.
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Affiliation(s)
- Jung Hwan Yu
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul 120-752, Korea
| | - Su Jin Song
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul 120-752, Korea
| | - Ara Kim
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul 120-752, Korea
| | - Yoonjeong Choi
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul 120-752, Korea
| | - Jo Woon Seok
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul 120-752, Korea
| | - Hyo Jung Kim
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Korea
| | - Yoo Jeong Lee
- Division of Metabolic Disease, Center for Biomedical Sciences, National Institutes of Health, Cheongwon-gun, Chungbuk 363-951, Korea
| | - Kwan Sik Lee
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul 120-752, Korea
| | - Jae-Woo Kim
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul 120-752, Korea.,Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 120-752, Korea
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36
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Compe E, Egly JM. Nucleotide Excision Repair and Transcriptional Regulation: TFIIH and Beyond. Annu Rev Biochem 2016; 85:265-90. [DOI: 10.1146/annurev-biochem-060815-014857] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Emmanuel Compe
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique/Institut National de la Santé et de la Recherche Médicale/Université de Strasbourg, 67404 Illkirch Cedex, Commune Urbaine Strasbourg, France; ,
| | - Jean-Marc Egly
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique/Institut National de la Santé et de la Recherche Médicale/Université de Strasbourg, 67404 Illkirch Cedex, Commune Urbaine Strasbourg, France; ,
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37
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Kuschal C, Botta E, Orioli D, Digiovanna JJ, Seneca S, Keymolen K, Tamura D, Heller E, Khan SG, Caligiuri G, Lanzafame M, Nardo T, Ricotti R, Peverali FA, Stephens R, Zhao Y, Lehmann AR, Baranello L, Levens D, Kraemer KH, Stefanini M. GTF2E2 Mutations Destabilize the General Transcription Factor Complex TFIIE in Individuals with DNA Repair-Proficient Trichothiodystrophy. Am J Hum Genet 2016; 98:627-42. [PMID: 26996949 DOI: 10.1016/j.ajhg.2016.02.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 02/10/2016] [Indexed: 12/24/2022] Open
Abstract
The general transcription factor IIE (TFIIE) is essential for transcription initiation by RNA polymerase II (RNA pol II) via direct interaction with the basal transcription/DNA repair factor IIH (TFIIH). TFIIH harbors mutations in two rare genetic disorders, the cancer-prone xeroderma pigmentosum (XP) and the cancer-free, multisystem developmental disorder trichothiodystrophy (TTD). The phenotypic complexity resulting from mutations affecting TFIIH has been attributed to the nucleotide excision repair (NER) defect as well as to impaired transcription. Here, we report two unrelated children showing clinical features typical of TTD who harbor different homozygous missense mutations in GTF2E2 (c.448G>C [p.Ala150Pro] and c.559G>T [p.Asp187Tyr]) encoding the beta subunit of transcription factor IIE (TFIIEβ). Repair of ultraviolet-induced DNA damage was normal in the GTF2E2 mutated cells, indicating that TFIIE was not involved in NER. We found decreased protein levels of the two TFIIE subunits (TFIIEα and TFIIEβ) as well as decreased phosphorylation of TFIIEα in cells from both children. Interestingly, decreased phosphorylation of TFIIEα was also seen in TTD cells with mutations in ERCC2, which encodes the XPD subunit of TFIIH, but not in XP cells with ERCC2 mutations. Our findings support the theory that TTD is caused by transcriptional impairments that are distinct from the NER disorder XP.
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Affiliation(s)
- Christiane Kuschal
- Dermatology Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Elena Botta
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Via Abbiategrasso 207, 27100 Pavia, Italy
| | - Donata Orioli
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Via Abbiategrasso 207, 27100 Pavia, Italy
| | - John J Digiovanna
- Dermatology Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Sara Seneca
- Center for Medical Genetics, Research Group Reproduction and Genetics, UZ Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium
| | - Kathelijn Keymolen
- Center for Medical Genetics, Research Group Reproduction and Genetics, UZ Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium
| | - Deborah Tamura
- Dermatology Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Elizabeth Heller
- Dermatology Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Sikandar G Khan
- Dermatology Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Giuseppina Caligiuri
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Via Abbiategrasso 207, 27100 Pavia, Italy
| | - Manuela Lanzafame
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Via Abbiategrasso 207, 27100 Pavia, Italy
| | - Tiziana Nardo
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Via Abbiategrasso 207, 27100 Pavia, Italy
| | - Roberta Ricotti
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Via Abbiategrasso 207, 27100 Pavia, Italy
| | - Fiorenzo A Peverali
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Via Abbiategrasso 207, 27100 Pavia, Italy
| | - Robert Stephens
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702, USA; Advanced Biomedical Computing Center, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702, USA
| | - Yongmei Zhao
- Advanced Biomedical Computing Center, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702, USA
| | - Alan R Lehmann
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Laura Baranello
- Laboratory of Pathology, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - David Levens
- Laboratory of Pathology, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Kenneth H Kraemer
- Dermatology Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA.
| | - Miria Stefanini
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Via Abbiategrasso 207, 27100 Pavia, Italy.
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Hallenborg P, Petersen RK, Kouskoumvekaki I, Newman JW, Madsen L, Kristiansen K. The elusive endogenous adipogenic PPARγ agonists: Lining up the suspects. Prog Lipid Res 2016; 61:149-62. [DOI: 10.1016/j.plipres.2015.11.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 11/06/2015] [Accepted: 11/10/2015] [Indexed: 02/07/2023]
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Xu Y, Jin J, Zhang W, Zhang Z, Gao J, Liu Q, Zhou C, Xu Q, Shi H, Hou Y, Shi J. EGFR/MDM2 signaling promotes NF-κB activation via PPARγ degradation. Carcinogenesis 2015; 37:215-222. [PMID: 26718225 DOI: 10.1093/carcin/bgv252] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 12/22/2015] [Indexed: 11/13/2022] Open
Abstract
Dysregulated expression of epidermal growth factor receptor (EGFR) has been implicated in many cancer events, while peroxisome proliferator-activated receptor γ (PPARγ) negatively regulates cancer progression. The molecular mechanism of EGFR interaction with PPARγ is still unclear. Here, we found that nuclear EGFR induced phosphorylation of PPARγ at Tyr-74 leading to PPARγ ubiquitination and degradation by mouse double minute 2 (MDM2) ubiquitin ligase. PPARγ degradation by EGFR/MDM2 signaling resulted in accumulation of nuclear factor-kappaB (NF-κB)/p65 protein levels and increasing NF-κB activation. In contrast, PPARγ-Y74A mutant reversed this event. Moreover, PPARγ-Y74A mutant suppressed cell proliferation and increased chemotherapeutic agent-induced cancer cell sensitivity. Importantly, the clinical findings show that the nuclear phosphorylation of PPARγ-Y74 and EGFR expression in colonic cancer tissues was higher than that in control normal tissues. Thus, our study revealed a novel molecular mechanism that nuclear EGFR/NF-κB signaling promoted cell proliferation by destructing PPARγ function, which provides a novel strategy for cancer treatment.
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Affiliation(s)
- Ying Xu
- Department of Oncology, The Affiliated Wujin Hospital, Jiangsu University, Changzhou, Jiangsu 213037, People's Republic of China.,Institute of Life Science, Jiangsu University, Zhenjiang, Jiangsu 212013, People's Republic of China.,Department of Central Laboratory and
| | - Jianhua Jin
- Department of Oncology, The Affiliated Wujin Hospital, Jiangsu University , Changzhou, Jiangsu 213037 , People's Republic of China
| | - Wenbo Zhang
- Institute of Life Science, Jiangsu University, Zhenjiang, Jiangsu 212013, People's Republic of China.,Department of General Surgery, The Affiliated People's Hospital, Jiangsu University, Zhenjiang, Jiangsu 212002, People's Republic of China
| | - Zhi Zhang
- Institute of Life Science, Jiangsu University , Zhenjiang, Jiangsu 212013 , People's Republic of China
| | - Jiaming Gao
- Institute of Life Science, Jiangsu University , Zhenjiang, Jiangsu 212013 , People's Republic of China
| | - Qian Liu
- Department of Oncology, The Affiliated Wujin Hospital, Jiangsu University , Changzhou, Jiangsu 213037 , People's Republic of China
| | - Chenglin Zhou
- Jiangsu Taizhou People's Hospital , Jiangsu 225309 , People's Republic of China
| | - Qinggang Xu
- Department of Oncology, The Affiliated Wujin Hospital, Jiangsu University , Changzhou, Jiangsu 213037 , People's Republic of China
| | - Haifeng Shi
- Department of Oncology, The Affiliated Wujin Hospital, Jiangsu University , Changzhou, Jiangsu 213037 , People's Republic of China
| | - Yongzhong Hou
- Department of Oncology, The Affiliated Wujin Hospital, Jiangsu University, Changzhou, Jiangsu 213037, People's Republic of China.,Institute of Life Science, Jiangsu University, Zhenjiang, Jiangsu 212013, People's Republic of China
| | - Juanjuan Shi
- Institute of Life Science, Jiangsu University , Zhenjiang, Jiangsu 212013 , People's Republic of China
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Kawai M. Adipose tissue and bone: role of PPARγ in adipogenesis and osteogenesis. Horm Mol Biol Clin Investig 2015; 15:105-13. [PMID: 25436737 DOI: 10.1515/hmbci-2013-0036] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 08/05/2013] [Indexed: 01/24/2023]
Abstract
Peroxisome proliferator-activated receptor-γ (PPARγ) is a critical factor for the reciprocal regulation of adipogenesis and osteogenesis. Because of their insulin-sensitizing effect, PPARγ agonists, the thiazolidinediones (TZDs), have been widely used for the treatment of type 2 diabetes mellitus; however, the use of TZDs has also been revealed to cause bone loss and bone fractures. The nodal point of regulation of skeletal metabolism by PPARγ activation may reside in its role in cell fate determination of mesenchymal stem cells toward adipogenesis at the expense of osteogenesis. In addition, accumulating evidence demonstrates that PPARγ possesses a circadian expression profile and plays an important role in the skeletal and adipose metabolism regulated by the circadian clock network. Recently, we have shown that nocturnin, a circadian-regulated gene, enhances PPARγ activity, resulting in the suppression of osteogenesis and enhancement of adipogenesis, thus providing additional evidence of the link between circadian networks and PPARγ. In this review, we will focus on the emerging concept of PPARγ as a regulator for skeletal metabolism and summarize recent findings about one of the mechanisms on how PPARγ is connected to the circadian-regulatory system, which involves nocturnin.
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Affiliation(s)
- Masanobu Kawai
- Department of Bone and Mineral Research, Osaka Medical Center and Research Institute for Maternal and Child Health, 840 Izumi, Osaka, Japan.
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41
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Choi SS, Park J, Choi JH. Revisiting PPARγ as a target for the treatment of metabolic disorders. BMB Rep 2015; 47:599-608. [PMID: 25154720 PMCID: PMC4281338 DOI: 10.5483/bmbrep.2014.47.11.174] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Indexed: 02/03/2023] Open
Abstract
As the prevalence of obesity has increased explosively over the last several decades, associated metabolic disorders, including type 2 diabetes, dyslipidemia, hypertension, and cardiovascular diseases, have been also increased. Thus, new strategies for preventing and treating them are needed. The nuclear peroxisome proliferator-activated receptors (PPARs) are involved fundamentally in regulating energy homeostasis; thus, they have been considered attractive drug targets for addressing metabolic disorders. Among the PPARs, PPARγ is a master regulator of gene expression for metabolism, inflammation, and other pathways in many cell types, especially adipocytes. It is a physiological receptor of the
potent anti-diabetic drugs of the thiazolidinediones (TZDs) class, including rosiglitazone (Avandia). However, TZDs have undesirable and severe side effects, such as weight gain, fluid
retention, and cardiovascular dysfunction. Recently, many reports have suggested that PPARγ could be modulated by post-translational modifications (PTMs), and modulation of
PTM has been considered as novel approaches for treating metabolic disorders with fewer side effects than the TZDs. In this review, we discuss how PTM of PPARγ may be regulated and issues to be considered in making novel anti-diabetic drugs that can modulate the PTM of PPARγ. [BMB Reports 2014; 47(11): 599-608]
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Affiliation(s)
- Sun-Sil Choi
- Department of Biological Science, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea
| | - Jiyoung Park
- Department of Biological Science, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea
| | - Jang Hyun Choi
- Department of Biological Science, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea
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Jang MK, Jung MH. ATF3 inhibits PPARγ-stimulated transactivation in adipocyte cells. Biochem Biophys Res Commun 2014; 456:80-5. [PMID: 25446101 DOI: 10.1016/j.bbrc.2014.11.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 11/14/2014] [Indexed: 11/19/2022]
Abstract
Previously, we reported that activating transcription factor 3 (ATF3) downregulates peroxisome proliferator activated receptor (PPARγ) gene expression and inhibits adipocyte differentiation in 3T3-L1 cells. Here, we investigated another role of ATF3 on the regulation of PPARγ activity. ATF3 inhibited PPARγ-stimulated transactivation of PPARγ responsive element (PPRE)-containing reporter or GAL4/PPARγ chimeric reporter. Thus, ATF3 effectively repressed rosiglitazone-stimulated expression of adipocyte fatty acid binding protein (aP2), PPARγ target gene, in 3T3-L1 cells. Coimmunoprecipitation and GST pulldown assay demonstrated that ATF3 interacted with PPARγ. Accordingly, ATF3 prevented PPARγ from binding to PPRE on the aP2 promoter. Furthermore, ATF3 suppressed p300-mediated transcriptional coactivation of PPRE-containing reporter. Chromatin immunoprecipitation assay showed that overexpression of ATF3 blocked both binding of PPARγ and recruitment of p300 to PPRE on aP2 promoter induced by rosiglitazone treatment in 3T3-L1 cells. Taken together, these results suggest that ATF3 interacts with PPARγ and represses PPARγ-mediated transactivation through suppression of p300-stimulated coactivation in 3T3-L1 cells, which may play a role in inhibition of adipocyte differentiation.
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Affiliation(s)
- Min-Kyung Jang
- School of Korean Medicine, Pusan National University, #49 Busandae hak-ro, Mulguem-eup, Yangsan-si, Gyeongnam 609-735, South Korea
| | - Myeong Ho Jung
- School of Korean Medicine, Pusan National University, #49 Busandae hak-ro, Mulguem-eup, Yangsan-si, Gyeongnam 609-735, South Korea.
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43
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Traboulsi H, Davoli S, Catez P, Egly JM, Compe E. Dynamic partnership between TFIIH, PGC-1α and SIRT1 is impaired in trichothiodystrophy. PLoS Genet 2014; 10:e1004732. [PMID: 25340339 PMCID: PMC4207666 DOI: 10.1371/journal.pgen.1004732] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 09/04/2014] [Indexed: 12/05/2022] Open
Abstract
The expression of protein-coding genes requires the selective role of many transcription factors, whose coordinated actions remain poorly understood. To further grasp the molecular mechanisms that govern transcription, we focused our attention on the general transcription factor TFIIH, which gives rise, once mutated, to Trichothiodystrophy (TTD), a rare autosomal premature-ageing disease causing inter alia, metabolic dysfunctions. Since this syndrome could be connected to transcriptional defects, we investigated the ability of a TTD mouse model to cope with food deprivation, knowing that energy homeostasis during fasting involves an accurate regulation of the gluconeogenic genes in the liver. Abnormal amounts of gluconeogenic enzymes were thus observed in TTD hepatic parenchyma, which was related to the dysregulation of the corresponding genes. Strikingly, such gene expression defects resulted from the inability of PGC1-α to fulfill its role of coactivator. Indeed, extensive molecular analyses unveiled that wild-type TFIIH cooperated in an ATP-dependent manner with PGC1-α as well as with the deacetylase SIRT1, thereby contributing to the PGC1-α deacetylation by SIRT1. Such dynamic partnership was, however, impaired when TFIIH was mutated, having as a consequence the disruption of PGC1-α recruitment to the promoter of target genes. Therefore, besides a better understanding of the etiology of TFIIH-related disease, our results shed light on the synergistic relationship that exist between different types of transcription factors, which is necessary to properly regulate the expression of protein coding genes. In eukaryotes, the expression of genes encoding proteins requires the action of hundreds of factors, together with the RNA polymerase II. While these factors are timely and selectively required for the expression of a given gene, little is known about their partnership upon gene expression. Our results reveal a cooperation between different types of transcription factors, namely the general transcription factor TFIIH, the cofactor PGC-1α and the deacetylase SIRT1. Such partnership is however impaired when TFIIH is mutated, as observed in Trichothiodystrophy patients that develop premature ageing. These results thus shed light on the coordinated action of factors during transcription and allow us to better understand molecular deficiencies observed in many human diseases.
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Affiliation(s)
- Hussein Traboulsi
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, Strasbourg, France
| | - Serena Davoli
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, Strasbourg, France
| | - Philippe Catez
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, Strasbourg, France
| | - Jean-Marc Egly
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, Strasbourg, France
- * E-mail: (JME); (EC)
| | - Emmanuel Compe
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, Strasbourg, France
- * E-mail: (JME); (EC)
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Tian L, Wang C, Hagen FK, Gormley M, Addya S, Soccio R, Casimiro MC, Zhou J, Powell MJ, Xu P, Deng H, Sauve AA, Pestell RG. Acetylation-defective mutant of Pparγ is associated with decreased lipid synthesis in breast cancer cells. Oncotarget 2014; 5:7303-15. [PMID: 25229978 PMCID: PMC4202124 DOI: 10.18632/oncotarget.2371] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 08/18/2014] [Indexed: 01/09/2023] Open
Abstract
In our prior publications we characterized a conserved acetylation motif (K(R)xxKK) of evolutionarily related nuclear receptors. Recent reports showed that peroxisome proliferator activated receptor gamma (PPARγ) deacetylation by SIRT1 is involved in delaying cellular senescence and maintaining the brown remodeling of white adipose tissue. However, it still remains unknown whether lysyl residues 154 and 155 (K154/155) of the conserved acetylation motif (RIHKK) in Pparγ1 are acetylated. Herein, we demonstrate that Pparγ1 is acetylated and regulated by both endogenous TSA-sensitive and NAD-dependent deacetylases. Acetylation of lysine 154 was identified by mass spectrometry (MS) while deacetylation of lysine 155 by SIRT1 was confirmed by in vitro deacetylation assay. An in vivo labeling assay revealed K154/K155 as bona fide acetylation sites. The conserved acetylation sites of Pparγ1 and the catalytic domain of SIRT1 are both required for the interaction between Pparγ1 and SIRT1. Sirt1 and Pparγ1 converge to govern lipid metabolism in vivo. Acetylation-defective mutants of Pparγ1 were associated with reduced lipid synthesis in ErbB2 overexpressing breast cancer cells. Together, these results suggest that the conserved lysyl residues K154/K155 of Pparγ1 are acetylated and play an important role in lipid synthesis in ErbB2-positive breast cancer cells.
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Affiliation(s)
- Lifeng Tian
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Chenguang Wang
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Fred K Hagen
- Department of Biochemistry and Biophysics, University of Rochester, Rochester, NY, USA
| | - Michael Gormley
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Sankar Addya
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Raymond Soccio
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Department of Genetics, and The Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Mathew C Casimiro
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Jie Zhou
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Michael J Powell
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Ping Xu
- Department of Pharmacology, Weill Medical College of Cornell University, York Avenue LC216, New York, NY, USA
| | - Haiteng Deng
- Proteomics Resource Center, Rockefeller University, New York, NY, USA
| | - Anthony A Sauve
- Department of Pharmacology, Weill Medical College of Cornell University, York Avenue LC216, New York, NY, USA
| | - Richard G Pestell
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
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Yin J, Gan P, Zhou F, Wang J. Sensitive detection of transcription factors using near-infrared fluorescent solid-phase rolling circle amplification. Anal Chem 2014; 86:2572-9. [PMID: 24475783 DOI: 10.1021/ac403758p] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
This study describes a method for analyzing transcription factor (TF) activity, near-infrared fluorescent solid-phase rolling circle amplification (NIRF-sRCA). This method analyzes TF activity in four steps: (i) incubate DNA with protein sample and isolate TF-bound DNA, (ii) hybridize the TF-bound DNA and rolling circle to DNA microarray, (iii) amplify the TF-bound DNA with sRCA that contains biotin-labeled dUTP, and (iv) detect sRCA products by binding of NIRF-labeled streptavidin and NIRF imaging. This method was validated by proof-of-concept detection of purified TF protein and cell nuclear extract. Detection of purified TF protein demonstrated that NIRF-sRCA could quantitatively detect NF-κB p50 protein, and as little as 6.94 ng (∼140 fmol) of this protein was detected. Detection of nuclear extract revealed that NIRF-sRCA could specifically and quantitatively detect NF-κB p50 activity in HeLa cell nuclear extracts, and the activity of this TF in as little as 0.625 μg of nuclear extracts could be detected. Detection of nuclear extract also revealed that NIRF-sRCA could detect the relative activities of multiple TFs in HeLa cell nuclear extracts and the fold induction of multiple TFs in the TNFα-induced HeLa cell nuclear extracts. Therefore, this study provides a new tool for studying TFs.
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Affiliation(s)
- Junhuan Yin
- State Key Laboratory of Bioelectronics, Southeast University , Nanjing 210096, China
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46
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Wu H, Roks AJ. Genomic instability and vascular aging: A focus on nucleotide excision repair. Trends Cardiovasc Med 2014; 24:61-8. [DOI: 10.1016/j.tcm.2013.06.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Revised: 06/19/2013] [Accepted: 06/20/2013] [Indexed: 11/26/2022]
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CDK5-induced p-PPARγ(Ser 112) downregulates GFAP via PPREs in developing rat brain: effect of metal mixture and troglitazone in astrocytes. Cell Death Dis 2014; 5:e1033. [PMID: 24481447 PMCID: PMC4040704 DOI: 10.1038/cddis.2013.514] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Revised: 11/16/2013] [Accepted: 11/20/2013] [Indexed: 11/08/2022]
Abstract
The peroxisome proliferator-activated receptor gamma (PPARγ), a group of ligand-activated transcriptional factors, is expressed in glial fibrillary acidic protein (GFAP)-immunoreactive astrocytes. Here, we investigated the role of PPARγ in regulating GFAP using a mixture of As, Cd and Pb (metal mixture, MM) that induces apoptosis and aberrant morphology in rat brain astrocytes. We observed a phospho PPARγ (serine 112 (S112)) (p-PPARγ (S112))-mediated downregulation of GFAP in the MM-exposed astrocytes. We validated this using pure PPARγ agonist, troglitazone (TZ). As reported with MM, TZ induced astrocyte damage owing to reduced GFAP. In silico analysis in the non-coding region of GFAP gene revealed two PPARγ response elements (PPREs); inverted repeat 10 and direct repeat 1 sequences. Gel shift and chromatin immunoprecipitation assays demonstrated enhancement in binding of p-PPARγ (S112) to the sequences, and luciferase reporter assay revealed strong repression of GFAP via PPREs, in response to both MM and TZ. This indicated that suppression in GFAP indeed occurs through direct regulation of these elements by p-PPARγ (S112). Signaling studies proved that MM, as well as TZ, activated the cyclin-dependent kinase 5 (CDK5) and enhanced its interaction with PPARγ resulting into increased p-PPARγ (S112). The p-CDK5 levels were dependent on proximal activation of extracellular signal-regulated protein kinase 1/2 and downstream Jun N-terminal kinase. Taken together, these results are the first to delineate downregulation of GFAP through genomic and non-genomic signaling of PPARγ. It also brings forth a resemblance of TZ with MM in terms of astrocyte disarray in developing brain.
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Zhou F, Ling X, Yin J, Wang J. Analyzing transcription factor activity using near infrared fluorescent bridge polymerase chain reaction. Anal Biochem 2013; 448:105-12. [PMID: 24333250 DOI: 10.1016/j.ab.2013.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 11/26/2013] [Accepted: 12/02/2013] [Indexed: 02/05/2023]
Abstract
This study has developed a new method, near infrared fluorescent bridge polymerase chain reaction (NIRF-bPCR), for analyzing transcription factor (TF) activity. This method was first used to detect the activity of purified nuclear factor kappa B (NF-κB) p50. The results demonstrated that this method could quantitatively detect the activity of p50 protein at less than 115ng (∼ 2320fmol), and the detection limit reached as little as 6.94ng (∼ 140fmol) of p50 protein. This method was then used to detect TF activity in cell extracts. The results revealed that this method could specifically detect NF-κB activity in HeLa cell nuclear extracts. Finally, this method was used to detect the activities of multiple TFs in a protein sample. The results showed that this method could detect the activities of six TFs-NF-κB, AP-1, TFIID, CREB, NF-E2, and p53-in the TNFα-induced and -uninduced HeLa cell nuclear extracts. Calculation of the fold induction of six TFs revealed that NF-κB, CREB, and AP1 were activated by TNFα induction in HeLa cells, in agreement with the detection results of other methods. Therefore, this study provides a new tool for analyzing TF activity. This study also revealed that NIRF-bPCR may be used as a new method for detecting DNA molecules.
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Affiliation(s)
- Fei Zhou
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing 210096, China
| | - Xiaoqian Ling
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing 210096, China
| | - Junhuan Yin
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing 210096, China
| | - Jinke Wang
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing 210096, China.
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Kaushik Tiwari M, Rogers FA. XPD-dependent activation of apoptosis in response to triplex-induced DNA damage. Nucleic Acids Res 2013; 41:8979-94. [PMID: 23913414 PMCID: PMC3799437 DOI: 10.1093/nar/gkt670] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
DNA sequences capable of forming triplexes are prevalent in the human genome and have been found to be intrinsically mutagenic. Consequently, a balance between DNA repair and apoptosis is critical to counteract their effect on genomic integrity. Using triplex-forming oligonucleotides to synthetically create altered helical distortions, we have determined that pro-apoptotic pathways are activated by the formation of triplex structures. Moreover, the TFIIH factor, XPD, occupies a central role in triggering apoptosis in response to triplex-induced DNA strand breaks. Here, we show that triplexes are capable of inducing XPD-independent double strand breaks, which result in the formation of γH2AX foci. XPD was subsequently recruited to the triplex-induced double strand breaks and co-localized with γH2AX at the damage site. Furthermore, phosphorylation of H2AX tyrosine 142 was found to stimulate the signaling pathway of XPD-dependent apoptosis. We suggest that this mechanism may play an active role in minimizing genomic instability induced by naturally occurring noncanonical structures, perhaps protecting against cancer initiation.
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Affiliation(s)
- Meetu Kaushik Tiwari
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
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50
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The serine/threonine phosphatase PPM1B (PP2Cβ) selectively modulates PPARγ activity. Biochem J 2013; 451:45-53. [PMID: 23320500 DOI: 10.1042/bj20121113] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Reversible phosphorylation is a widespread molecular mechanism to regulate the function of cellular proteins, including transcription factors. Phosphorylation of the nuclear receptor PPARγ (peroxisome-proliferator-activated receptor γ) at two conserved serine residue (Ser(112) and Ser(273)) results in an altered transcriptional activity of this transcription factor. So far, only a very limited number of cellular enzymatic activities has been described which can dephosphorylate nuclear receptors. In the present study we used immunoprecipitation assays coupled to tandem MS analysis to identify novel PPARγ-regulating proteins. We identified the serine/threonine phosphatase PPM1B [PP (protein phosphatase), Mg(2+)/Mn(2+) dependent, 1B; also known as PP2Cβ] as a novel PPARγ-interacting protein. Endogenous PPM1B protein is localized in the nucleus of mature 3T3-L1 adipocytes where it can bind to PPARγ. Furthermore we show that PPM1B can directly dephosphorylate PPARγ, both in intact cells and in vitro. In addition PPM1B increases PPARγ-mediated transcription via dephosphorylation of Ser(112). Finally, we show that knockdown of PPM1B in 3T3-L1 adipocytes blunts the expression of some PPARγ target genes while leaving others unaltered. These findings qualify the phosphatase PPM1B as a novel selective modulator of PPARγ activity.
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