1
|
Luna-Arias JP, Castro-Muñozledo F. Participation of the TBP-associated factors (TAFs) in cell differentiation. J Cell Physiol 2024; 239:e31167. [PMID: 38126142 DOI: 10.1002/jcp.31167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/04/2023] [Accepted: 11/27/2023] [Indexed: 12/23/2023]
Abstract
The understanding of the mechanisms that regulate gene expression to establish differentiation programs and determine cell lineages, is one of the major challenges in Developmental Biology. Besides the participation of tissue-specific transcription factors and epigenetic processes, the role of general transcription factors has been ignored. Only in recent years, there have been scarce studies that address this issue. Here, we review the studies on the biological activity of some TATA-box binding protein (TBP)-associated factors (TAFs) during the proliferation of stem/progenitor cells and their involvement in cell differentiation. Particularly, the accumulated evidence suggests that TAF4, TAF4b, TAF7L, TAF8, TAF9, and TAF10, among others, participate in nervous system development, adipogenesis, myogenesis, and epidermal differentiation; while TAF1, TAF7, TAF15 may be involved in the regulation of stem cell proliferative abilities and cell cycle progression. On the other hand, evidence suggests that TBP variants such as TBPL1 and TBPL2 might be regulating some developmental processes such as germ cell maturation and differentiation, myogenesis, or ventral specification during development. Our analysis shows that it is necessary to study in greater depth the biological function of these factors and its participation in the assembly of specific transcription complexes that contribute to the differential gene expression that gives rise to the great diversity of cell types existing in an organism. The understanding of TAFs' regulation might lead to the development of new therapies for patients which suffer from mutations, alterations, and dysregulation of these essential elements of the transcriptional machinery.
Collapse
Affiliation(s)
- Juan Pedro Luna-Arias
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, México City, Mexico
| | - Federico Castro-Muñozledo
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, México City, Mexico
| |
Collapse
|
2
|
Yoon JH, Kim S. Learning gene networks under SNP perturbation using SNP and allele-specific expression data. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.23.563661. [PMID: 37961468 PMCID: PMC10634764 DOI: 10.1101/2023.10.23.563661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Allele-specific expression quantification from RNA-seq reads provides opportunities to study the control of gene regulatory networks by cis-acting and trans-acting genetic variants. Many existing methods performed a single-gene and single-SNP association analysis to identify expression quantitative trait loci (eQTLs), and placed the eQTLs against known gene networks for functional interpretation. Instead, we view eQTL data as a capture of the effects of perturbation of gene regulatory system by a large number of genetic variants and reconstruct a gene network perturbed by eQTLs. We introduce a statistical framework called CiTruss for simultaneously learning a gene network and cis-acting and trans-acting eQTLs that perturb this network, given population allele-specific expression and SNP data. CiTruss uses a multi-level conditional Gaussian graphical model to model trans-acting eQTLs perturbing the expression of both alleles in gene network at the top level and cis-acting eQTLs perturbing the expression of each allele at the bottom level. We derive a transformation of this model that allows efficient learning for large-scale human data. Our analysis of the GTEx and LG×SM advanced intercross line mouse data for multiple tissue types with CiTruss provides new insights into genetics of gene regulation. CiTruss revealed that gene networks consist of local subnetworks over proximally located genes and global subnetworks over genes scattered across genome, and that several aspects of gene regulation by eQTLs such as the impact of genetic diversity, pleiotropy, tissue-specific gene regulation, and local and long-range linkage disequilibrium among eQTLs can be explained through these local and global subnetworks.
Collapse
Affiliation(s)
- Jun Ho Yoon
- Computational Biology Department, Carnegie Mellon University, Pittsburgh, PA 15213, United States of America
| | | |
Collapse
|
3
|
Leigh RS, Välimäki MJ, Kaynak BL, Ruskoaho HJ. TAF1 bromodomain inhibition as a candidate epigenetic driver of congenital heart disease. Biochim Biophys Acta Mol Basis Dis 2023; 1869:166689. [PMID: 36958711 DOI: 10.1016/j.bbadis.2023.166689] [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: 10/20/2022] [Revised: 03/01/2023] [Accepted: 03/06/2023] [Indexed: 03/25/2023]
Abstract
Heart formation requires transcriptional regulators that underlie congenital anomalies and the fetal gene program activated during heart failure. Attributing the effects of congenital heart disease (CHD) missense variants to disruption of specific protein domains allows for a mechanistic understanding of CHDs and improved diagnostics. A combined chemical and genetic approach was employed to identify novel CHD drivers, consisting of chemical screening during pluripotent stem cell (PSC) differentiation, gene expression analyses of native tissues and primary cell culture models, and the in vitro study of damaging missense variants from CHD patients. An epigenetic inhibitor of the TATA-Box Binding Protein Associated Factor 1 (TAF1) bromodomain was uncovered in an unbiased chemical screen for activators of atrial and ventricular fetal myosins in differentiating PSCs, leading to the development of a high affinity inhibitor (5.1 nM) of the TAF1 bromodomain, a component of the TFIID complex. TAF1 bromodomain inhibitors were tested for their effects on stem cell viability and cardiomyocyte differentiation, implicating a role for TAF1 in cardiogenesis. Damaging TAF1 missense variants from CHD patients were studied by mutational analysis of the TAF1 bromodomain, demonstrating a repressive role of TAF1 that can be abrogated by the introduction of damaging bromodomain variants or chemical TAF1 bromodomain inhibition. These results indicate that targeting the TAF1/TFIID complex with chemical compounds modulates cardiac transcription and identify an epigenetically-driven CHD mechanism due to damaging variants within the TAF1 bromodomain.
Collapse
Affiliation(s)
- Robert S Leigh
- Drug Research Program, Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Mika J Välimäki
- Drug Research Program, Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Bogac L Kaynak
- Drug Research Program, Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland.
| | - Heikki J Ruskoaho
- Drug Research Program, Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland.
| |
Collapse
|
4
|
Chen KY, De Angulo A, Guo X, More A, Ochsner SA, Lopez E, Saul D, Pang W, Sun Y, McKenna NJ, Tong Q. Adipocyte-Specific Ablation of PU.1 Promotes Energy Expenditure and Ameliorates Metabolic Syndrome in Aging Mice. FRONTIERS IN AGING 2022; 2:803482. [PMID: 35822007 PMCID: PMC9261351 DOI: 10.3389/fragi.2021.803482] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 12/13/2021] [Indexed: 12/03/2022]
Abstract
Objective: Although PU.1/Spi1 is known as a master regulator for macrophage development and function, we have reported previously that it is also expressed in adipocytes and is transcriptionally induced in obesity. Here, we investigated the role of adipocyte PU.1 in the development of the age-associated metabolic syndrome. Methods: We generated mice with adipocyte-specific PU.1 knockout, assessed metabolic changes in young and older adult PU.1fl/fl (control) and AdipoqCre PU.1fl/fl (aPU.1KO) mice, including body weight, body composition, energy expenditure, and glucose homeostasis. We also performed transcriptional analyses using RNA-Sequencing of adipocytes from these mice. Results: aPU.1KO mice have elevated energy expenditure at a young age and decreased adiposity and increased insulin sensitivity in later life. Corroborating these observations, transcriptional network analysis indicated the existence of validated, adipocyte PU.1-modulated regulatory hubs that direct inflammatory and thermogenic gene expression programs. Conclusion: Our data provide evidence for a previously uncharacterized role of PU.1 in the development of age-associated obesity and insulin resistance.
Collapse
Affiliation(s)
- Ke Yun Chen
- Department of Pediatrics, USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX, United States
| | - Alejandra De Angulo
- Department of Pediatrics, USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX, United States
| | - Xin Guo
- Department of Pediatrics, USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX, United States
- Department of Nutrition and Food Hygiene, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Aditya More
- Department of Pediatrics, USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX, United States
| | - Scott A. Ochsner
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, United States
| | - Eduardo Lopez
- Department of Pediatrics, USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX, United States
| | - David Saul
- Department of Pediatrics, USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX, United States
| | - Weijun Pang
- Department of Pediatrics, USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX, United States
- Northwestern University of Agriculture and Forestry, Yangling, China
| | - Yuxiang Sun
- Department of Pediatrics, USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX, United States
- Department of Nutrition, Texas A&M University, College Station, TX, United States
| | - Neil J. McKenna
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, United States
- *Correspondence: Neil J. McKenna, ; Qiang Tong,
| | - Qiang Tong
- Department of Pediatrics, USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX, United States
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Huffington Center on Aging, Houston, TX, United States
- Department of Medicine, Baylor College of Medicine, Huffington Center on Aging, Houston, TX, United States
- *Correspondence: Neil J. McKenna, ; Qiang Tong,
| |
Collapse
|
5
|
Role of Distinct Fat Depots in Metabolic Regulation and Pathological Implications. Rev Physiol Biochem Pharmacol 2022; 186:135-176. [PMID: 35915363 DOI: 10.1007/112_2022_73] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
People suffering from obesity and associated metabolic disorders including diabetes are increasing exponentially around the world. Adipose tissue (AT) distribution and alteration in their biochemical properties play a major role in the pathogenesis of these diseases. Emerging evidence suggests that AT heterogeneity and depot-specific physiological changes are vital in the development of insulin resistance in peripheral tissues like muscle and liver. Classically, AT depots are classified into white adipose tissue (WAT) and brown adipose tissue (BAT); WAT is the site of fatty acid storage, while BAT is a dedicated organ of metabolic heat production. The discovery of beige adipocyte clusters in WAT depots indicates AT heterogeneity has a more central role than hither to ascribed. Therefore, we have discussed in detail the current state of understanding on cellular and molecular origin of different AT depots and their relevance toward physiological metabolic homeostasis. A major focus is to highlight the correlation between altered WAT distribution in the body and metabolic pathogenesis in animal models and humans. We have also underscored the disparity in the molecular (including signaling) changes in various WAT tissues during diabetic pathogenesis. Exercise-mediated beneficial alteration in WAT physiology/distribution that protects against metabolic disorders is evolving. Here we have discussed the depot-specific biochemical adjustments induced by different forms of exercise. A detailed understanding of the molecular details of inter-organ crosstalk via substrate utilization/storage and signaling through chemokines provide strategies to target selected WAT depots to pharmacologically mimic the benefits of exercise countering metabolic diseases including diabetes.
Collapse
|
6
|
Chernov AV, Shubayev VI. Sexual Dimorphism of Early Transcriptional Reprogramming in Dorsal Root Ganglia After Peripheral Nerve Injury. Front Mol Neurosci 2021; 14:779024. [PMID: 34966260 PMCID: PMC8710713 DOI: 10.3389/fnmol.2021.779024] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 11/19/2021] [Indexed: 01/18/2023] Open
Abstract
Peripheral nerve injury induces genome-wide transcriptional reprogramming of first-order neurons and auxiliary cells of dorsal root ganglia (DRG). Accumulating experimental evidence suggests that onset and mechanistic principles of post-nerve injury processes are sexually dimorphic. We examined largely understudied aspects of early transcriptional events in DRG within 24 h after sciatic nerve axotomy in mice of both sexes. Using high-depth RNA sequencing (>50 million reads/sample) to pinpoint sexually dimorphic changes related to regeneration, immune response, bioenergy, and sensory functions, we identified a higher number of transcriptional changes in male relative to female DRG. In males, the decline in ion channel transcripts was accompanied by the induction of innate immune cascades via TLR, chemokine, and Csf1-receptor axis and robust regenerative programs driven by Sox, Twist1/2, and Pax5/9 transcription factors. Females demonstrated nerve injury-specific transcriptional co-activation of the actinin 2 network. The predicted upstream regulators and interactive networks highlighted the role of novel epigenetic factors and genetic linkage to sex chromosomes as hallmarks of gene regulation post-axotomy. We implicated epigenetic X chromosome inactivation in the regulation of immune response activity uniquely in females. Sexually dimorphic regulation of MMP/ADAMTS metalloproteinases and their intrinsic X-linked regulator Timp1 contributes to extracellular matrix remodeling integrated with pro-regenerative and immune functions. Lexis1 non-coding RNA involved in LXR-mediated lipid metabolism was identified as a novel nerve injury marker. Together, our data identified unique early response triggers of sex-specific peripheral nerve injury regulation to gain mechanistic insights into the origin of female- and male-prevalent sensory neuropathies.
Collapse
Affiliation(s)
- Andrei V Chernov
- Department of Anesthesiology, University of California, San Diego, San Diego, CA, United States.,VA San Diego Healthcare System, San Diego, CA, United States
| | - Veronica I Shubayev
- Department of Anesthesiology, University of California, San Diego, San Diego, CA, United States.,VA San Diego Healthcare System, San Diego, CA, United States
| |
Collapse
|
7
|
Wu SC, Münger K. Role and Clinical Utility of Cancer/Testis Antigens in Head and Neck Squamous Cell Carcinoma. Cancers (Basel) 2021; 13:cancers13225690. [PMID: 34830845 PMCID: PMC8616139 DOI: 10.3390/cancers13225690] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/03/2021] [Accepted: 11/11/2021] [Indexed: 12/15/2022] Open
Abstract
Cancer/testis (CT) antigens exhibit selective expression predominantly in immunoprivileged tissues in non-pathological contexts but are aberrantly expressed in diverse cancers. Due to their expression pattern, they have historically been attractive targets for immunotherapies. A growing number of studies implicate CT antigens in almost all hallmarks of cancer, suggesting that they may act as cancer drivers. CT antigens are expressed in head and neck squamous cell carcinomas. However, their role in the pathogenesis of these cancers remains poorly studied. Given that CT antigens hold intriguing potential as therapeutic targets and as biomarkers for prognosis and that they can provide novel insights into oncogenic mechanisms, their further study in the context of head and squamous cell carcinoma is warranted.
Collapse
Affiliation(s)
- Sharon Changshan Wu
- Molecular Microbiology Program, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA 02111, USA;
| | - Karl Münger
- Department of Developmental, Molecular, and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, USA
- Correspondence:
| |
Collapse
|
8
|
Sloutskin A, Shir-Shapira H, Freiman RN, Juven-Gershon T. The Core Promoter Is a Regulatory Hub for Developmental Gene Expression. Front Cell Dev Biol 2021; 9:666508. [PMID: 34568311 PMCID: PMC8461331 DOI: 10.3389/fcell.2021.666508] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 08/25/2021] [Indexed: 11/13/2022] Open
Abstract
The development of multicellular organisms and the uniqueness of each cell are achieved by distinct transcriptional programs. Multiple processes that regulate gene expression converge at the core promoter region, an 80 bp region that directs accurate transcription initiation by RNA polymerase II (Pol II). In recent years, it has become apparent that the core promoter region is not a passive DNA component, but rather an active regulatory module of transcriptional programs. Distinct core promoter compositions were demonstrated to result in different transcriptional outputs. In this mini-review, we focus on the role of the core promoter, particularly its downstream region, as the regulatory hub for developmental genes. The downstream core promoter element (DPE) was implicated in the control of evolutionarily conserved developmental gene regulatory networks (GRNs) governing body plan in both the anterior-posterior and dorsal-ventral axes. Notably, the composition of the basal transcription machinery is not universal, but rather promoter-dependent, highlighting the importance of specialized transcription complexes and their core promoter target sequences as key hubs that drive embryonic development, differentiation and morphogenesis across metazoan species. The extent of transcriptional activation by a specific enhancer is dependent on its compatibility with the relevant core promoter. The core promoter content also regulates transcription burst size. Overall, while for many years it was thought that the specificity of gene expression is primarily determined by enhancers, it is now clear that the core promoter region comprises an important regulatory module in the intricate networks of developmental gene expression.
Collapse
Affiliation(s)
- Anna Sloutskin
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Hila Shir-Shapira
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Richard N. Freiman
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, United States
| | - Tamar Juven-Gershon
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
| |
Collapse
|
9
|
Ghnaimawi S, Rebello L, Baum J, Huang Y. DHA but not EPA induces the trans-differentiation of C2C12 cells into white-like adipocytes phenotype. PLoS One 2021; 16:e0249438. [PMID: 34473703 PMCID: PMC8412409 DOI: 10.1371/journal.pone.0249438] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 08/12/2021] [Indexed: 01/21/2023] Open
Abstract
Muscle derived stem cells (MDSCs) and myoblast play an important role in myotube regeneration when muscle tissue is injured. However, these cells can be induced to differentiate into adipocytes once exposed to PPARγ activator like EPA and DHA that are highly suggested during pregnancy. The objective of this study aims at determining the identity of trans-differentiated cells by exploring the effect of EPA and DHA on C2C12 undergoing differentiation into brown and white adipocytes. DHA but not EPA committed C2C12 cells reprograming into white like adipocyte phenotype. Also, DHA promoted the expression of lipolysis regulating genes but had no effect on genes regulating β-oxidation referring to its implication in lipid re-esterification. Furthermore, DHA impaired C2C12 cells differentiation into brown adipocytes through reducing the thermogenic capacity and mitochondrial biogenesis of derived cells independent of UCP1. Accordingly, DHA treated groups showed an increased accumulation of lipid droplets and suppressed mitochondrial maximal respiration and spare respiratory capacity. EPA, on the other hand, reduced myogenesis regulating genes, but no significant differences were observed in the expression of adipogenesis key genes. Likewise, EPA suppressed the expression of WAT signature genes indicating that EPA and DHA have an independent role on white adipogensis. Unlike DHA treatment, EPA supplementation had no effect on the differential of C2C12 cells into brown adipocytes. In conclusion, DHA is a potent adipogenic and lipogenic factor that can change the metabolic profile of muscle cells by increasing myocellular fat.
Collapse
Affiliation(s)
- Saeed Ghnaimawi
- Department of Cell and Molecular Biology Program, University of Arkansas, Fayetteville, North Carolina, United States of America
| | - Lisa Rebello
- Department of Cell and Molecular Biology Program, University of Arkansas, Fayetteville, North Carolina, United States of America
| | - Jamie Baum
- Department of Food Science, Division of Agriculture, University of Arkansas, Fayetteville, AR, United States of America
| | - Yan Huang
- Department of Animal Science, Division of Agriculture, University of Arkansas, Fayetteville, North Carolina, United States of America
| |
Collapse
|
10
|
Brandão BB, Poojari A, Rabiee A. Thermogenic Fat: Development, Physiological Function, and Therapeutic Potential. Int J Mol Sci 2021; 22:5906. [PMID: 34072788 PMCID: PMC8198523 DOI: 10.3390/ijms22115906] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 04/30/2021] [Accepted: 05/27/2021] [Indexed: 12/11/2022] Open
Abstract
The concerning worldwide increase of obesity and chronic metabolic diseases, such as T2D, dyslipidemia, and cardiovascular disease, motivates further investigations into preventive and alternative therapeutic approaches. Over the past decade, there has been growing evidence that the formation and activation of thermogenic adipocytes (brown and beige) may serve as therapy to treat obesity and its associated diseases owing to its capacity to increase energy expenditure and to modulate circulating lipids and glucose levels. Thus, understanding the molecular mechanism of brown and beige adipocytes formation and activation will facilitate the development of strategies to combat metabolic disorders. Here, we provide a comprehensive overview of pathways and players involved in the development of brown and beige fat, as well as the role of thermogenic adipocytes in energy homeostasis and metabolism. Furthermore, we discuss the alterations in brown and beige adipose tissue function during obesity and explore the therapeutic potential of thermogenic activation to treat metabolic syndrome.
Collapse
Affiliation(s)
- Bruna B. Brandão
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA;
| | - Ankita Poojari
- Department of Physiology & Pharmacology, Thomas J. Long School of Pharmacy & Health Sciences, University of the Pacific, Stockton, CA 95211, USA;
| | - Atefeh Rabiee
- Department of Physiology & Pharmacology, Thomas J. Long School of Pharmacy & Health Sciences, University of the Pacific, Stockton, CA 95211, USA;
| |
Collapse
|
11
|
Holzman MA, Ryckman A, Finkelstein TM, Landry-Truchon K, Schindler KA, Bergmann JM, Jeannotte L, Mansfield JH. HOXA5 Participates in Brown Adipose Tissue and Epaxial Skeletal Muscle Patterning and in Brown Adipocyte Differentiation. Front Cell Dev Biol 2021; 9:632303. [PMID: 33732701 PMCID: PMC7959767 DOI: 10.3389/fcell.2021.632303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 02/02/2021] [Indexed: 11/13/2022] Open
Abstract
Brown adipose tissue (BAT) plays critical thermogenic, metabolic and endocrine roles in mammals, and aberrant BAT function is associated with metabolic disorders including obesity and diabetes. The major BAT depots are clustered at the neck and forelimb levels, and arise largely within the dermomyotome of somites, from a common progenitor with skeletal muscle. However, many aspects of BAT embryonic development are not well understood. Hoxa5 patterns other tissues at the cervical and brachial levels, including skeletal, neural and respiratory structures. Here, we show that Hoxa5 also positively regulates BAT development, while negatively regulating formation of epaxial skeletal muscle. HOXA5 protein is expressed in embryonic preadipocytes and adipocytes as early as embryonic day 12.5. Hoxa5 null mutant embryos and rare, surviving adults show subtly reduced iBAT and sBAT formation, as well as aberrant marker expression, lower adipocyte density and altered lipid droplet morphology. Conversely, the epaxial muscles that arise from a common dermomyotome progenitor are expanded in Hoxa5 mutants. Conditional deletion of Hoxa5 with Myf5/Cre can reproduce both BAT and epaxial muscle phenotypes, indicating that HOXA5 is necessary within Myf5-positive cells for proper BAT and epaxial muscle development. However, recombinase-based lineage tracing shows that Hoxa5 does not act cell-autonomously to repress skeletal muscle fate. Interestingly, Hoxa5-dependent regulation of adipose-associated transcripts is conserved in lung and diaphragm, suggesting a shared molecular role for Hoxa5 in multiple tissues. Together, these findings establish a role for Hoxa5 in embryonic BAT development.
Collapse
Affiliation(s)
- Miriam A. Holzman
- Department of Biology, Barnard College, Columbia University, New York, NY, United States
| | - Abigail Ryckman
- Department of Biology, Barnard College, Columbia University, New York, NY, United States
| | - Tova M. Finkelstein
- Department of Biology, Barnard College, Columbia University, New York, NY, United States
| | - Kim Landry-Truchon
- Centre de Recherche sur le Cancer de l’Université Laval, CRCHU de Québec-Université Laval (Oncology), Québec City, QC, Canada
| | - Kyra A. Schindler
- Department of Biology, Barnard College, Columbia University, New York, NY, United States
| | - Jenna M. Bergmann
- Department of Biology, Barnard College, Columbia University, New York, NY, United States
| | - Lucie Jeannotte
- Centre de Recherche sur le Cancer de l’Université Laval, CRCHU de Québec-Université Laval (Oncology), Québec City, QC, Canada
| | - Jennifer H. Mansfield
- Department of Biology, Barnard College, Columbia University, New York, NY, United States
| |
Collapse
|
12
|
Shinde AB, Song A, Wang QA. Brown Adipose Tissue Heterogeneity, Energy Metabolism, and Beyond. Front Endocrinol (Lausanne) 2021; 12:651763. [PMID: 33953697 PMCID: PMC8092391 DOI: 10.3389/fendo.2021.651763] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 03/18/2021] [Indexed: 01/19/2023] Open
Abstract
Brown adipocyte in brown adipose tissue (BAT) specializes in expending energy through non-shivering thermogenesis, a process that produces heat either by uncoupling protein 1 (UCP1) dependent uncoupling of mitochondrial respiration or by UCP1 independent mechanisms. Apart from this, there is ample evidence suggesting that BAT has an endocrine function. Studies in rodents point toward its vital roles in glucose and lipid homeostasis, making it an important therapeutic target for treating metabolic disorders related to morbidities such as obesity and type 2 diabetes. The rediscovery of thermogenically active BAT depots in humans by several independent research groups in the last decade has revitalized interest in BAT as an even more promising therapeutic intervention. Over the last few years, there has been overwhelming interest in understanding brown adipocyte's developmental lineages and how brown adipocyte uniquely utilizes energy beyond UCP1 mediated uncoupling respiration. These new discoveries would be leveraged for designing novel therapeutic interventions for metabolic disorders.
Collapse
Affiliation(s)
- Abhijit Babaji Shinde
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute, City of Hope Medical Center, Duarte, CA, United States
| | - Anying Song
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute, City of Hope Medical Center, Duarte, CA, United States
| | - Qiong A. Wang
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute, City of Hope Medical Center, Duarte, CA, United States
- Comprehensive Cancer Center, Beckman Research Institute, City of Hope Medical Center, Duarte, CA, United States
- *Correspondence: Qiong A. Wang,
| |
Collapse
|
13
|
Maurer S, Harms M, Boucher J. The colorful versatility of adipocytes: white-to-brown transdifferentiation and its therapeutic potential in humans. FEBS J 2020; 288:3628-3646. [PMID: 32621398 DOI: 10.1111/febs.15470] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/17/2020] [Accepted: 06/29/2020] [Indexed: 12/22/2022]
Abstract
Brown and brite adipocytes contribute to energy expenditure through nonshivering thermogenesis. Though these cell types are thought to arise primarily from the de novo differentiation of precursor cells, their abundance is also controlled through the transdifferentiation of mature white adipocytes. Here, we review recent advances in our understanding of the regulation of white-to-brown transdifferentiation, as well as the conversion of brown and brite adipocytes to dormant, white-like fat cells. Converting mature white adipocytes into brite cells or reactivating dormant brown and brite adipocytes has emerged as a strategy to ameliorate human metabolic disorders. We analyze the evidence of learning from mice and how they translate to humans to ultimately scrutinize the relevance of this concept. Moreover, we estimate that converting a small percentage of existing white fat mass in obese subjects into active brite adipocytes could be sufficient to achieve meaningful benefits in metabolism. In conclusion, novel browning agents have to be identified before adipocyte transdifferentiation can be realized as a safe and efficacious therapy.
Collapse
Affiliation(s)
- Stefanie Maurer
- Bioscience Metabolism, Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Matthew Harms
- Bioscience Metabolism, Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Jeremie Boucher
- Bioscience Metabolism, Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.,Lundberg Laboratory for Diabetes Research, University of Gothenburg, Gothenburg, Sweden.,Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, Sweden
| |
Collapse
|
14
|
Ghnaimawi S, Baum J, Liyanage R, Huang Y. Concurrent EPA and DHA Supplementation Impairs Brown Adipogenesis of C2C12 Cells. Front Genet 2020; 11:531. [PMID: 32595696 PMCID: PMC7303889 DOI: 10.3389/fgene.2020.00531] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 05/01/2020] [Indexed: 12/27/2022] Open
Abstract
Maternal dietary supplementation of n−3 polyunsaturated fatty acids (n−3 PUFAs), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), is considered to play positive roles in fetal neuro system development. However, maternal n−3 PUFAs may induce molecular reprogramming of uncommitted fetal myoblasts into adipocyte phenotype, in turn affecting lipid metabolism and energy expenditure of the offspring. The objective of this in vitro study was to investigate the combined effects of EPA and DHA on C2C12 cells undergoing brown adipogenic differentiation. C2C12 myoblasts were cultured to confluency and then treated with brown adipogenic differentiation medium with and without 50 μM EPA and 50 μM DHA. After differentiation, mRNA and protein samples were collected. Gene expression and protein levels were analyzed by real-time PCR and western blot. General Proteomics analysis was conducted using mass spectrometric evaluation. The effect of EPA and DHA on cellular oxygen consumption was measured using a Seahorse XFP Analyzer. Cells treated with n−3 PUFAs had significantly less (P < 0.05) expression of the brown adipocyte marker genes PGC1α, DIO2, and UCP3. Expression of mitochondrial biogenesis-related genes TFAM, PGC1α, and PGC1β were significantly downregulated (P < 0.05) by n−3 PUFAs treatment. Expression of mitochondrial electron transportation chain (ETC)-regulated genes were significantly inhibited (P < 0.05) by n−3 PUFAs, including ATP5J2, COX7a1, and COX8b. Mass spectrometric and western blot evaluation showed protein levels of enzymes which regulate the ETC and Krebs cycle, including ATP synthase α and β (F1F0 complex), citrate synthase, succinate CO-A ligase, succinate dehydrogenase (complex II), ubiquinol-cytochrome c reductase complex subunits (complex III), aconitate hydratase, cytochrome c, and pyruvate carboxylase were all decreased in the n−3 PUFAs group (P < 0.05). Genomic and proteomic changes were accompanied by mitochondrial dysfunction, represented by significantly reduced oxygen consumption rate, ATP production, and proton leak (P < 0.05). This study suggested that EPA and DHA may alter the BAT fate of myoblasts by inhibiting mitochondrial biogenesis and activity and induce white-like adipogenesis, shifting the metabolism from lipid oxidation to synthesis.
Collapse
Affiliation(s)
- Saeed Ghnaimawi
- Department of Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, United States
| | - Jamie Baum
- Department of Food Science, Division of Agriculture, University of Arkansas, Fayetteville, AR, United States
| | - Rohana Liyanage
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR, United States
| | - Yan Huang
- Department of Animal Science, Division of Agriculture, University of Arkansas, Fayetteville, AR, United States
| |
Collapse
|
15
|
Gura MA, Mikedis MM, Seymour KA, de Rooij DG, Page DC, Freiman RN. Dynamic and regulated TAF gene expression during mouse embryonic germ cell development. PLoS Genet 2020; 16:e1008515. [PMID: 31914128 PMCID: PMC7010400 DOI: 10.1371/journal.pgen.1008515] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 02/10/2020] [Accepted: 11/11/2019] [Indexed: 12/02/2022] Open
Abstract
Germ cells undergo many developmental transitions before ultimately becoming either eggs or sperm, and during embryonic development these transitions include epigenetic reprogramming, quiescence, and meiosis. To begin understanding the transcriptional regulation underlying these complex processes, we examined the spatial and temporal expression of TAF4b, a variant TFIID subunit required for fertility, during embryonic germ cell development. By analyzing published datasets and using our own experimental system to validate these expression studies, we determined that both Taf4b mRNA and protein are highly germ cell-enriched and that Taf4b mRNA levels dramatically increase from embryonic day 12.5–18.5. Surprisingly, additional mRNAs encoding other TFIID subunits are coordinately upregulated through this time course, including Taf7l and Taf9b. The expression of several of these germ cell-enriched TFIID genes is dependent upon Dazl and/or Stra8, known regulators of germ cell development and meiosis. Together, these data suggest that germ cells employ a highly specialized and dynamic form of TFIID to drive the transcriptional programs that underlie mammalian germ cell development. Assisted reproductive therapy and fertility preservation are increasingly used to improve human reproduction across the world, yet there are still many unanswered questions regarding what factors govern the development of eggs and sperm and how these factors work together. We previously identified a subunit of the general transcription factor TFIID, TAF4b, that is essential for fertility. However, many basic characteristics of how Taf4b and its associated TFIID family members contribute to the formation of healthy sperm and eggs in mice and humans remain unknown. In this study, we find that mouse Taf4b and several closely related TFIID subunits become highly abundant during mouse embryonic gonad development, specifically in the cells that ultimately become eggs and sperm. Here, we analyzed data from public repositories and isolated these developing cells to examine their gene expression patterns throughout embryonic development. Together these data suggest that the dynamic expression of Taf4b and other TFIID family members are dependent on the well-established reproductive cell regulators Dazl and Stra8. This understanding of Taf4b gene expression and regulation in mouse reproductive cell development is likely conserved during development of human cells and offers novel insights into the interconnectedness of the factors that govern the formation of healthy eggs and sperm.
Collapse
Affiliation(s)
- Megan A. Gura
- Brown University, MCB Graduate Program and Department of Molecular Biology, Cell Biology and Biochemistry, Providence, RI, United States of America
| | | | - Kimberly A. Seymour
- Brown University, MCB Graduate Program and Department of Molecular Biology, Cell Biology and Biochemistry, Providence, RI, United States of America
| | | | - David C. Page
- Whitehead Institute, Cambridge, MA, United States of America
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States of America
- Howard Hughes Medical Institute, Whitehead Institute, Cambridge, MA, United States of America
| | - Richard N. Freiman
- Brown University, MCB Graduate Program and Department of Molecular Biology, Cell Biology and Biochemistry, Providence, RI, United States of America
- * E-mail:
| |
Collapse
|
16
|
Antonova SV, Boeren J, Timmers HTM, Snel B. Epigenetics and transcription regulation during eukaryotic diversification: the saga of TFIID. Genes Dev 2019; 33:888-902. [PMID: 31123066 PMCID: PMC6672047 DOI: 10.1101/gad.300475.117] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In this perspective, Antonova et al. determine the evolutionary history of all TFIID subunits and place them in a functional context to understand their diversification. This analysis of TFIID evolution exemplifies how phylogenetic protein interrogation aids in uncovering existing structures, drawing parallels between related complexes and challenges offered by genome expansions that can be countered by exploiting chromatin modifications. The basal transcription factor TFIID is central for RNA polymerase II-dependent transcription. Human TFIID is endowed with chromatin reader and DNA-binding domains and protein interaction surfaces. Fourteen TFIID TATA-binding protein (TBP)-associated factor (TAF) subunits assemble into the holocomplex, which shares subunits with the Spt–Ada–Gcn5–acetyltransferase (SAGA) coactivator. Here, we discuss the structural and functional evolution of TFIID and its divergence from SAGA. Our orthologous tree and domain analyses reveal dynamic gains and losses of epigenetic readers, plant-specific functions of TAF1 and TAF4, the HEAT2-like repeat in TAF2, and, importantly, the pre-LECA origin of TFIID and SAGA. TFIID evolution exemplifies the dynamic plasticity in transcription complexes in the eukaryotic lineage.
Collapse
Affiliation(s)
- Simona V Antonova
- Molecular Cancer Research and Regenerative Medicine, University Medical Centre Utrecht, 3584 CT Utrecht, The Netherlands
| | - Jeffrey Boeren
- Department of Developmental Biology, Erasmus MC, 3015 CN Rotterdam, The Netherlands
| | - H T Marc Timmers
- Molecular Cancer Research and Regenerative Medicine, University Medical Centre Utrecht, 3584 CT Utrecht, The Netherlands.,Department of Urology, Medical Centre-University of Freiburg, 79106 Freiburg, Germany.,Deutsches Konsortium für Translationale Krebsforschung (DKTK) Standort Freiburg, Deutsches Krebsforschungszentrum (DKFZ), 69120 Heidelberg, Germany
| | - Berend Snel
- Theoretical Biology and Bioinformatics, Department of Biology, Utrecht University, 3584 CH Utrecht, The Netherlands
| |
Collapse
|
17
|
Drosophila TRF2 and TAF9 regulate lipid droplet size and phospholipid fatty acid composition. PLoS Genet 2017; 13:e1006664. [PMID: 28273089 PMCID: PMC5362240 DOI: 10.1371/journal.pgen.1006664] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 03/22/2017] [Accepted: 02/28/2017] [Indexed: 11/19/2022] Open
Abstract
The general transcription factor TBP (TATA-box binding protein) and its associated factors (TAFs) together form the TFIID complex, which directs transcription initiation. Through RNAi and mutant analysis, we identified a specific TBP family protein, TRF2, and a set of TAFs that regulate lipid droplet (LD) size in the Drosophila larval fat body. Among the three Drosophila TBP genes, trf2, tbp and trf1, only loss of function of trf2 results in increased LD size. Moreover, TRF2 and TAF9 regulate fatty acid composition of several classes of phospholipids. Through RNA profiling, we found that TRF2 and TAF9 affects the transcription of a common set of genes, including peroxisomal fatty acid β-oxidation-related genes that affect phospholipid fatty acid composition. We also found that knockdown of several TRF2 and TAF9 target genes results in large LDs, a phenotype which is similar to that of trf2 mutants. Together, these findings provide new insights into the specific role of the general transcription machinery in lipid homeostasis. Lipid droplets (LD) are main lipid storage structures in most cells. The size of LDs varies greatly in different cell types or different metabolic states to accommodate cellular functions and metabolism demands. How cells regulate the lipid storage and LD dynamics is not fully understood. Here, we identified that general transcription factors, including a specific TBP (TATA-box binding protein) family protein TRF2 (TBP-related factor 2) and several TAFs (TBP-associated factors), regulate LD size in the fruitfly larval fat body. Moreover, quantitated lipid analysis reveals that TRF2 and TAF9 affect the fatty acid composition of several classes of phospholipids. We showed that TRF2 and TAF9 regulate transcription of several target genes, including peroxisomal fatty acid β-oxidation-related genes which likely mediate the effect of TRF2 and TAF9 on phospholipid fatty acid composition. We also found that overexpression of some target genes restores the LD phenotype in trf2 mutants. Our findings therefore reveal specific roles of general transcription factors in lipid homeostasis.
Collapse
|
18
|
Loft A, Forss I, Mandrup S. Genome-Wide Insights into the Development and Function of Thermogenic Adipocytes. Trends Endocrinol Metab 2017; 28:104-120. [PMID: 27979331 DOI: 10.1016/j.tem.2016.11.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 11/01/2016] [Accepted: 11/07/2016] [Indexed: 12/31/2022]
Abstract
Brown and brown-like adipocytes are specialized adipocytes with a high capacity to convert metabolic energy to heat. This function is not only eminent in supporting organismal thermogenesis, but may also have potential in the fight against obesity. The latter has spurred a massive interest in understanding the development and regulation of these thermogenic adipocytes. Here, we review how genome-wide studies based on next-generation sequencing have provided insight into how the chromatin and transcriptional landscapes are established in thermogenic adipocytes and how thermogenic signals can change the genomic programming of white adipocytes. Furthermore, we discuss how the integration of genomic data can be used to discover novel transcriptional pathways that may be modulated as part of therapeutic strategies for the treatment of obesity.
Collapse
Affiliation(s)
- Anne Loft
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark; Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, 85764 Neuherberg, Germany; Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - Isabel Forss
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Susanne Mandrup
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark.
| |
Collapse
|
19
|
Inagaki T, Sakai J, Kajimura S. Transcriptional and epigenetic control of brown and beige adipose cell fate and function. Nat Rev Mol Cell Biol 2016; 17:480-95. [PMID: 27251423 DOI: 10.1038/nrm.2016.62] [Citation(s) in RCA: 220] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
White adipocytes store excess energy in the form of triglycerides, whereas brown and beige adipocytes dissipate energy in the form of heat. This thermogenic function relies on the activation of brown and beige adipocyte-specific gene programmes that are coordinately regulated by adipose-selective chromatin architectures and by a set of unique transcriptional and epigenetic regulators. A number of transcriptional and epigenetic regulators are also required for promoting beige adipocyte biogenesis in response to various environmental stimuli. A better understanding of the molecular mechanisms governing the generation and function of brown and beige adipocytes is necessary to allow us to control adipose cell fate and stimulate thermogenesis. This may provide a therapeutic approach for the treatment of obesity and obesity-associated diseases, such as type 2 diabetes.
Collapse
Affiliation(s)
- Takeshi Inagaki
- Division of Metabolic Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan 153-8904.,The Translational Systems Biology and Medicine Initiative (TSBMI), Center for Disease Biology and Integrative Medicine, Faculty of Medicine, The University of Tokyo, Tokyo, Japan 113-8655
| | - Juro Sakai
- Division of Metabolic Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan 153-8904.,The Translational Systems Biology and Medicine Initiative (TSBMI), Center for Disease Biology and Integrative Medicine, Faculty of Medicine, The University of Tokyo, Tokyo, Japan 113-8655
| | - Shingo Kajimura
- UCSF Diabetes Center and Department of Cell and Tissue Biology, University of California, San Francisco, California 94143-0669, USA
| |
Collapse
|
20
|
Langer D, Martianov I, Alpern D, Rhinn M, Keime C, Dollé P, Mengus G, Davidson I. Essential role of the TFIID subunit TAF4 in murine embryogenesis and embryonic stem cell differentiation. Nat Commun 2016; 7:11063. [PMID: 27026076 PMCID: PMC4820908 DOI: 10.1038/ncomms11063] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 02/17/2016] [Indexed: 12/15/2022] Open
Abstract
TAF4 (TATA-binding protein-associated factor 4) and its paralogue TAF4b are components of the TFIID core module. We inactivated the murine Taf4a gene to address Taf4 function during embryogenesis. Here we show that Taf4a−/− embryos survive until E9.5 where primary germ layers and many embryonic structures are identified showing Taf4 is dispensable for their specification. In contrast, Taf4 is required for correct patterning of the trunk and anterior structures, ventral morphogenesis and proper heart positioning. Overlapping expression of Taf4a and Taf4b during embryogenesis suggests their redundancy at early stages. In agreement with this, Taf4a−/− embryonic stem cells (ESCs) are viable and comprise Taf4b-containing TFIID. Nevertheless, Taf4a−/− ESCs do not complete differentiation into glutamatergic neurons and cardiomyocytes in vitro due to impaired preinitiation complex formation at the promoters of critical differentiation genes. We define an essential role of a core TFIID TAF in differentiation events during mammalian embryogenesis. The role of TFIID core module TAFs (TATA-binding protein-associated factors) in embryogenesis is unknown. Here, the authors show that Taf4 is essential at mid-gestation and for complete neuronal differentiation of embryonic stem cells, but that Taf4a and Taf4b are redundant at early embryonic stages.
Collapse
Affiliation(s)
- Diana Langer
- Department of Functional Genomics and Cancer, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, 1 Rue Laurent Fries, 67404 Illkirch, France
| | - Igor Martianov
- Department of Functional Genomics and Cancer, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, 1 Rue Laurent Fries, 67404 Illkirch, France
| | - Daniel Alpern
- Department of Functional Genomics and Cancer, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, 1 Rue Laurent Fries, 67404 Illkirch, France.,L'École polytechnique fédérale de Lausanne, Route Cantonale, 1015 Lausanne, Switzerland
| | - Muriel Rhinn
- Department of Development and Stem Cells, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, 1 Rue Laurent Fries, 67404 Illkirch, France
| | - Céline Keime
- Department of Functional Genomics and Cancer, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, 1 Rue Laurent Fries, 67404 Illkirch, France
| | - Pascal Dollé
- Department of Development and Stem Cells, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, 1 Rue Laurent Fries, 67404 Illkirch, France
| | - Gabrielle Mengus
- Department of Functional Genomics and Cancer, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, 1 Rue Laurent Fries, 67404 Illkirch, France
| | - Irwin Davidson
- Department of Functional Genomics and Cancer, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, 1 Rue Laurent Fries, 67404 Illkirch, France
| |
Collapse
|
21
|
Mueller E. Browning and Graying: Novel Transcriptional Regulators of Brown and Beige Fat Tissues and Aging. Front Endocrinol (Lausanne) 2016; 7:19. [PMID: 26973598 PMCID: PMC4773441 DOI: 10.3389/fendo.2016.00019] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 02/15/2016] [Indexed: 11/13/2022] Open
Abstract
Obesity represents a major risk factor for the development of a number of metabolic disorders, including cardiovascular disease and type 2 diabetes. Since the discovery that brown and beige fat cells exist in adult humans and contribute to energy expenditure, increasing interest has been devoted to the understanding of the molecular switches turning on calorie utilization. It has been reported that the ability of thermogenic tissues to burn energy declines during aging, possibly contributing to the development of metabolic dysfunction late in life. This review will focus on the recently identified transcriptional modulators of brown and beige cells and will discuss the potential impact of some of these thermogenic factors on age-associated metabolic disorders.
Collapse
Affiliation(s)
- Elisabetta Mueller
- Genetics of Development and Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
- *Correspondence: Elisabetta Mueller,
| |
Collapse
|
22
|
X-ray phase-contrast tomography with a compact laser-driven synchrotron source. Proc Natl Acad Sci U S A 2015; 112:5567-72. [PMID: 25902493 DOI: 10.1073/pnas.1500938112] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Between X-ray tubes and large-scale synchrotron sources, a large gap in performance exists with respect to the monochromaticity and brilliance of the X-ray beam. However, due to their size and cost, large-scale synchrotrons are not available for more routine applications in small and medium-sized academic or industrial laboratories. This gap could be closed by laser-driven compact synchrotron light sources (CLS), which use an infrared (IR) laser cavity in combination with a small electron storage ring. Hard X-rays are produced through the process of inverse Compton scattering upon the intersection of the electron bunch with the focused laser beam. The produced X-ray beam is intrinsically monochromatic and highly collimated. This makes a CLS well-suited for applications of more advanced--and more challenging--X-ray imaging approaches, such as X-ray multimodal tomography. Here we present, to our knowledge, the first results of a first successful demonstration experiment in which a monochromatic X-ray beam from a CLS was used for multimodal, i.e., phase-, dark-field, and attenuation-contrast, X-ray tomography. We show results from a fluid phantom with different liquids and a biomedical application example in the form of a multimodal CT scan of a small animal (mouse, ex vivo). The results highlight particularly that quantitative multimodal CT has become feasible with laser-driven CLS, and that the results outperform more conventional approaches.
Collapse
|
23
|
Alpern D, Langer D, Ballester B, Le Gras S, Romier C, Mengus G, Davidson I. TAF4, a subunit of transcription factor II D, directs promoter occupancy of nuclear receptor HNF4A during post-natal hepatocyte differentiation. eLife 2014; 3:e03613. [PMID: 25209997 PMCID: PMC4359380 DOI: 10.7554/elife.03613] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 09/09/2014] [Indexed: 12/25/2022] Open
Abstract
The functions of the TAF subunits of mammalian TFIID in physiological processes remain poorly characterised. In this study, we describe a novel function of TAFs in directing genomic occupancy of a transcriptional activator. Using liver-specific inactivation in mice, we show that the TAF4 subunit of TFIID is required for post-natal hepatocyte maturation. TAF4 promotes pre-initiation complex (PIC) formation at post-natal expressed liver function genes and down-regulates a subset of embryonic expressed genes by increased RNA polymerase II pausing. The TAF4–TAF12 heterodimer interacts directly with HNF4A and in vivo TAF4 is necessary to maintain HNF4A-directed embryonic gene expression at post-natal stages and promotes HNF4A occupancy of functional cis-regulatory elements adjacent to the transcription start sites of post-natal expressed genes. Stable HNF4A occupancy of these regulatory elements requires TAF4-dependent PIC formation highlighting that these are mutually dependent events. Local promoter-proximal HNF4A–TFIID interactions therefore act as instructive signals for post-natal hepatocyte differentiation. DOI:http://dx.doi.org/10.7554/eLife.03613.001 To decode the information contained within a gene, a number of processes need to occur. For example, the DNA sequence that makes up the gene needs to be copied to make a molecule of RNA, which is then translated to build the corresponding protein. The first steps in the manufacture of RNA involve a structure called a ‘pre-initiation complex’ moving an enzyme called RNA polymerase II to the start of the gene that needs to be copied. The pre-initiation complex is made up of many types of protein, including a set of proteins called TAFs. However, the way that these proteins work in mammals is not well understood. There are good reasons for this: proteins are often studied by seeing what happens when the protein is removed, but many TAFs are so important that removing them is lethal. Alpern et al. have now studied the function of TAF4 by removing this protein from mouse liver cells. This causes severe hypoglycemia (that is, a drop in sugar levels in the blood). Moreover, it seems as if these cells start dying before they become fully mature. In liver cells lacking TAF4, some 1408 genes that are normally turned on just after birth are not properly switched on; these genes are necessary for the metabolic functions of the liver. Furthermore, 776 genes that are normally turned off after birth continue to be expressed. It seems that the absence of TAF4 sometimes disrupts the formation of the pre-initiation complex, which would slow down the production of RNA. However, it can also have the opposite effect by increasing the activity of RNA polymerase II, hence making too many copies of RNA from some genes. Alpern et al. also find that TAF4 is needed to allow a protein called HNF4A, which is important in the development of the liver and in controlling metabolism, to interact with over 7000 important DNA sequences. Mutations in HNF4A are responsible for a syndrome known as Maturity Onset of Diabetes in the Young. The next stage in this work will be to explore if these mutations influence the interaction between HNF4A and TAF4, and if they do, whether these changes contribute to this form of diabetes. DOI:http://dx.doi.org/10.7554/eLife.03613.002
Collapse
Affiliation(s)
- Daniil Alpern
- Department of Functional Genomics and Cancer, Institut de Genetique et de Biologie Moleculaire et Cellulaire, CNRS/INSERM/UDS, Illkirch, France
| | - Diana Langer
- Department of Functional Genomics and Cancer, Institut de Genetique et de Biologie Moleculaire et Cellulaire, CNRS/INSERM/UDS, Illkirch, France
| | - Benoit Ballester
- Laboratoire TAGC, Aix-Marseille Université, UMR1090, Marseille, France
| | - Stephanie Le Gras
- Department of Functional Genomics and Cancer, Institut de Genetique et de Biologie Moleculaire et Cellulaire, CNRS/INSERM/UDS, Illkirch, France
| | - Christophe Romier
- Department of Integrated Structural Biology, Institut de Genetique et de Biologie Moleculaire et Cellulaire, CNRS/INSERM/UDS, Illkirch, France
| | - Gabrielle Mengus
- Department of Functional Genomics and Cancer, Institut de Genetique et de Biologie Moleculaire et Cellulaire, CNRS/INSERM/UDS, Illkirch, France
| | - Irwin Davidson
- Department of Functional Genomics and Cancer, Institut de Genetique et de Biologie Moleculaire et Cellulaire, CNRS/INSERM/UDS, Illkirch, France
| |
Collapse
|
24
|
Abstract
Different members of the TAF family of proteins work in differentiated cells, such as motor neurons or brown fat cells, to control the expression of genes that are specific to each cell type.
Collapse
Affiliation(s)
- Katherine A Jones
- Katherine A Jones is in the Regulatory Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, United States
| |
Collapse
|