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Alfeghaly C, Castel G, Cazottes E, Moscatelli M, Moinard E, Casanova M, Boni J, Mahadik K, Lammers J, Freour T, Chauviere L, Piqueras C, Boers R, Boers J, Gribnau J, David L, Ouimette JF, Rougeulle C. XIST dampens X chromosome activity in a SPEN-dependent manner during early human development. Nat Struct Mol Biol 2024:10.1038/s41594-024-01325-3. [PMID: 38834912 DOI: 10.1038/s41594-024-01325-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 04/25/2024] [Indexed: 06/06/2024]
Abstract
XIST (X-inactive specific transcript) long noncoding RNA (lncRNA) is responsible for X chromosome inactivation (XCI) in placental mammals, yet it accumulates on both X chromosomes in human female preimplantation embryos without triggering X chromosome silencing. The XACT (X-active coating transcript) lncRNA coaccumulates with XIST on active X chromosomes and may antagonize XIST function. Here, we used human embryonic stem cells in a naive state of pluripotency to assess the function of XIST and XACT in shaping the X chromosome chromatin and transcriptional landscapes during preimplantation development. We show that XIST triggers the deposition of polycomb-mediated repressive histone modifications and dampens the transcription of most X-linked genes in a SPEN-dependent manner, while XACT deficiency does not significantly affect XIST activity or X-linked gene expression. Our study demonstrates that XIST is functional before XCI, confirms the existence of a transient process of X chromosome dosage compensation and reveals that XCI and dampening rely on the same set of factors.
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Affiliation(s)
- Charbel Alfeghaly
- Epigenetics and Cell Fate, CNRS, Université Paris Cité, Paris, France
| | - Gaël Castel
- Epigenetics and Cell Fate, CNRS, Université Paris Cité, Paris, France
| | - Emmanuel Cazottes
- Epigenetics and Cell Fate, CNRS, Université Paris Cité, Paris, France
| | | | - Eva Moinard
- Center for Research in Transplantation and Translational Immunology (CR2TI), CHU Nantes, Inserm, Nantes Université, Nantes, France
| | - Miguel Casanova
- Epigenetics and Cell Fate, CNRS, Université Paris Cité, Paris, France
| | - Juliette Boni
- Epigenetics and Cell Fate, CNRS, Université Paris Cité, Paris, France
| | - Kasturi Mahadik
- Epigenetics and Cell Fate, CNRS, Université Paris Cité, Paris, France
| | - Jenna Lammers
- Service de Biologie de la Reproduction, CHU Nantes, Nantes Université, Nantes, France
| | - Thomas Freour
- Service de Biologie de la Reproduction, CHU Nantes, Nantes Université, Nantes, France
| | - Louis Chauviere
- Epigenetics and Cell Fate, CNRS, Université Paris Cité, Paris, France
| | - Carla Piqueras
- Epigenetics and Cell Fate, CNRS, Université Paris Cité, Paris, France
| | - Ruben Boers
- Department of Developmental Biology, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Joachim Boers
- Department of Developmental Biology, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Joost Gribnau
- Department of Developmental Biology, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Laurent David
- Center for Research in Transplantation and Translational Immunology (CR2TI), CHU Nantes, Inserm, Nantes Université, Nantes, France
- BioCore, CNRS, CHU Nantes, Inserm, Nantes Université, Nantes, France
| | | | - Claire Rougeulle
- Epigenetics and Cell Fate, CNRS, Université Paris Cité, Paris, France.
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Yang B, Rong X, Jiang C, Long M, Liu A, Chen Q. Comprehensive analyses reveal the prognosis and biological function roles of chromatin regulators in lung adenocarcinoma. Aging (Albany NY) 2023; 15:3598-3620. [PMID: 37155150 PMCID: PMC10449281 DOI: 10.18632/aging.204693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 04/24/2023] [Indexed: 05/10/2023]
Abstract
The present study explored the prognosis and biological function roles of chromatin regulators (CRs) in patients with lung adenocarcinoma (LUAD). Using transcriptome profile and clinical follow-up data of LUAD dataset, we explored the molecular classification, developed, and validated a CR prognostic model, built an individual risk scoring system in LUAD, and compared the clinical and molecular characteristics between different subtypes and risk stratifications. We investigated the chemotherapy sensitivity and predicted potential immunotherapy response. Lastly, we collected the clinical samples and validated the prognosis and potential function role of NAPS2. Our study indicated that LUAD patients could be classified into two subtypes that had obviously different clinical background and molecular features. We constructed a prognostic model with eight CR genes, which was well validated in several other population cohort. We built high- and low-risk stratifications for LUAD patients. Patients from high-risk group were totally different from low-risk groups in clinical, biological function, gene mutation, microenvironment, and immune infiltration levels. We idented several potential molecular compounds for high-risk group treatment. We predicted that high-risk group may have poor immunotherapy response. We finally found that Neuronal PAS Domain Protein 2 (NPAS2) involved in the progression of LUAD via regulating cell adhesion. Our study indicated that CR involved in the progression of LUAD and affect their prognosis. Different therapeutic strategies should be developed for different molecular subtypes and risk stratifications. Our comprehensive analyses uncover specific determinants of CRs in LUAD and provides implications for investigating disease-associated CRs.
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Affiliation(s)
- Baishuang Yang
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Xueyao Rong
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Chen Jiang
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Meihua Long
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Aibin Liu
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Qiong Chen
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha 410008, China
- Xiangya Lung Cancer Center, Xiangya Hospital, Central South University, Changsha 410008, China
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Dossin F, Heard E. The Molecular and Nuclear Dynamics of X-Chromosome Inactivation. Cold Spring Harb Perspect Biol 2022; 14:a040196. [PMID: 34312245 PMCID: PMC9121902 DOI: 10.1101/cshperspect.a040196] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In female eutherian mammals, dosage compensation of X-linked gene expression is achieved during development through transcriptional silencing of one of the two X chromosomes. Following X chromosome inactivation (XCI), the inactive X chromosome remains faithfully silenced throughout somatic cell divisions. XCI is dependent on Xist, a long noncoding RNA that coats and silences the X chromosome from which it is transcribed. Xist coating triggers a cascade of chromosome-wide changes occurring at the levels of transcription, chromatin composition, chromosome structure, and spatial organization within the nucleus. XCI has emerged as a paradigm for the study of such crucial nuclear processes and the dissection of their functional interplay. In the past decade, the advent of tools to characterize and perturb these processes have provided an unprecedented understanding into their roles during XCI. The mechanisms orchestrating the initiation of XCI as well as its maintenance are thus being unraveled, although many questions still remain. Here, we introduce key aspects of the XCI process and review the recent discoveries about its molecular basis.
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Affiliation(s)
- François Dossin
- European Molecular Biology Laboratory, Director's Unit, 69117 Heidelberg, Germany
| | - Edith Heard
- European Molecular Biology Laboratory, Director's Unit, 69117 Heidelberg, Germany
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Predescu DN, Mokhlesi B, Predescu SA. The Impact of Sex Chromosomes in the Sexual Dimorphism of Pulmonary Arterial Hypertension. THE AMERICAN JOURNAL OF PATHOLOGY 2022; 192:582-594. [PMID: 35114193 PMCID: PMC8978209 DOI: 10.1016/j.ajpath.2022.01.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 12/14/2021] [Accepted: 01/11/2022] [Indexed: 02/09/2023]
Abstract
Pulmonary arterial hypertension (PAH) is a sex-biased disease with a poorly understood female prevalence. Emerging research suggests that nonhormonal factors, such as the XX or XY sex chromosome complement and sex bias in gene expression, may also lead to sex-based differences in PAH incidence, penetrance, and progression. Typically, one of females' two X chromosomes is epigenetically silenced to offer a gender-balanced gene expression. Recent data demonstrate that the long noncoding RNA X-inactive specific transcript, essential for X chromosome inactivation and dosage compensation of X-linked gene expression, shows elevated levels in female PAH lung specimens compared with controls. This molecular event leads to incomplete inactivation of the females' second X chromosome, abnormal expression of X-linked gene(s) involved in PAH pathophysiology, and a pulmonary artery endothelial cell (PAEC) proliferative phenotype. Moreover, the pathogenic proliferative p38 mitogen-activated protein kinase/ETS transcription factor ELK1 (Elk1)/cFos signaling is mechanistically linked to the sexually dimorphic proliferative response of PAECs in PAH. Apprehending the complicated relationship between long noncoding RNA X-inactive specific transcript and X-linked genes and how this relationship integrates into a sexually dimorphic proliferation of PAECs and PAH sex paradox remain challenging. We highlight herein new findings related to how the sex chromosome complement and sex-differentiated epigenetic mechanisms to control gene expression are decisive players in the sexual dimorphism of PAH. Pharmacologic interventions in the light of the newly elucidated mechanisms are discussed.
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Affiliation(s)
- Dan N Predescu
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, Rush University Medical Center, Chicago, Illinois.
| | - Babak Mokhlesi
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, Rush University Medical Center, Chicago, Illinois
| | - Sanda A Predescu
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, Rush University Medical Center, Chicago, Illinois
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Abstract
Herculean efforts by the Wellcome Sanger Institute, the National Cancer Institute, and the National Human Genome Research Institute to sequence thousands of tumors representing all major cancer types have yielded more than 700 genes that contribute to neoplastic growth when mutated, amplified, or deleted. While some of these genes (now included in the COSMIC Cancer Gene Census) encode proteins previously identified in hypothesis-driven experiments (oncogenic transcription factors, protein kinases, etc.), additional classes of cancer drivers have emerged, perhaps none more surprisingly than RNA-binding proteins (RBPs). Over 40 RBPs responsible for virtually all aspects of RNA metabolism, from synthesis to degradation, are recurrently mutated in cancer, and just over a dozen are considered major cancer drivers. This Review investigates whether and how their RNA-binding activities pertain to their oncogenic functions. Focusing on several well-characterized steps in RNA metabolism, we demonstrate that for virtually all cancer-driving RBPs, RNA processing activities are either abolished (the loss-of-function phenotype) or carried out with low fidelity (the LoFi phenotype). Conceptually, this suggests that in normal cells, RBPs act as gatekeepers maintaining proper RNA metabolism and the "balanced" proteome. From the practical standpoint, at least some LoFi phenotypes create therapeutic vulnerabilities, which are beginning to be exploited in the clinic.
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