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Bravo JI, Mizrahi CR, Kim S, Zhang L, Suh Y, Benayoun BA. An eQTL-based approach reveals candidate regulators of LINE-1 RNA levels in lymphoblastoid cells. PLoS Genet 2024; 20:e1011311. [PMID: 38848448 PMCID: PMC11189215 DOI: 10.1371/journal.pgen.1011311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 06/20/2024] [Accepted: 05/21/2024] [Indexed: 06/09/2024] Open
Abstract
Long interspersed element 1 (LINE-1; L1) are a family of transposons that occupy ~17% of the human genome. Though a small number of L1 copies remain capable of autonomous transposition, the overwhelming majority of copies are degenerate and immobile. Nevertheless, both mobile and immobile L1s can exert pleiotropic effects (promoting genome instability, inflammation, or cellular senescence) on their hosts, and L1's contributions to aging and aging diseases is an area of active research. However, because of the cell type-specific nature of transposon control, the catalogue of L1 regulators remains incomplete. Here, we employ an eQTL approach leveraging transcriptomic and genomic data from the GEUVADIS and 1000Genomes projects to computationally identify new candidate regulators of L1 RNA levels in lymphoblastoid cell lines. To cement the role of candidate genes in L1 regulation, we experimentally modulate the levels of top candidates in vitro, including IL16, STARD5, HSD17B12, and RNF5, and assess changes in TE family expression by Gene Set Enrichment Analysis (GSEA). Remarkably, we observe subtle but widespread upregulation of TE family expression following IL16 and STARD5 overexpression. Moreover, a short-term 24-hour exposure to recombinant human IL16 was sufficient to transiently induce subtle, but widespread, upregulation of L1 subfamilies. Finally, we find that many L1 expression-associated genetic variants are co-associated with aging traits across genome-wide association study databases. Our results expand the catalogue of genes implicated in L1 RNA control and further suggest that L1-derived RNA contributes to aging processes. Given the ever-increasing availability of paired genomic and transcriptomic data, we anticipate this new approach to be a starting point for more comprehensive computational scans for regulators of transposon RNA levels.
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Affiliation(s)
- Juan I. Bravo
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, United States of America
- Graduate program in the Biology of Aging, University of Southern California, Los Angeles, California, United States of America
| | - Chanelle R. Mizrahi
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, United States of America
- USC Gerontology Enriching MSTEM to Enhance Diversity in Aging Program, University of Southern California, Los Angeles, California, United States of America
| | - Seungsoo Kim
- Department of Obstetrics and Gynecology, Columbia University Irving Medical Center, New York, New York, United States of America
| | - Lucia Zhang
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, United States of America
- Quantitative and Computational Biology Department, USC Dornsife College of Letters, Arts and Sciences, Los Angeles, California, United States of America
| | - Yousin Suh
- Department of Obstetrics and Gynecology, Columbia University Irving Medical Center, New York, New York, United States of America
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, New York, United States of America
| | - Bérénice A. Benayoun
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, United States of America
- Molecular and Computational Biology Department, USC Dornsife College of Letters, Arts and Sciences, Los Angeles, California, United States of America
- Biochemistry and Molecular Medicine Department, USC Keck School of Medicine, Los Angeles, California, United States of America
- USC Norris Comprehensive Cancer Center, Epigenetics and Gene Regulation, Los Angeles, California, United States of America
- USC Stem Cell Initiative, Los Angeles, California, United States of America
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Bravo JI, Mizrahi CR, Kim S, Zhang L, Suh Y, Benayoun BA. An eQTL-based Approach Reveals Candidate Regulators of LINE-1 RNA Levels in Lymphoblastoid Cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.15.553416. [PMID: 37645920 PMCID: PMC10461994 DOI: 10.1101/2023.08.15.553416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Long interspersed element 1 (L1) are a family of autonomous, actively mobile transposons that occupy ~17% of the human genome. A number of pleiotropic effects induced by L1 (promoting genome instability, inflammation, or cellular senescence) have been observed, and L1's contributions to aging and aging diseases is an area of active research. However, because of the cell type-specific nature of transposon control, the catalogue of L1 regulators remains incomplete. Here, we employ an eQTL approach leveraging transcriptomic and genomic data from the GEUVADIS and 1000Genomes projects to computationally identify new candidate regulators of L1 RNA levels in lymphoblastoid cell lines. To cement the role of candidate genes in L1 regulation, we experimentally modulate the levels of top candidates in vitro, including IL16, STARD5, HSDB17B12, and RNF5, and assess changes in TE family expression by Gene Set Enrichment Analysis (GSEA). Remarkably, we observe subtle but widespread upregulation of TE family expression following IL16 and STARD5 overexpression. Moreover, a short-term 24-hour exposure to recombinant human IL16 was sufficient to transiently induce subtle, but widespread, upregulation of L1 subfamilies. Finally, we find that many L1 expression-associated genetic variants are co-associated with aging traits across genome-wide association study databases. Our results expand the catalogue of genes implicated in L1 RNA control and further suggest that L1-derived RNA contributes to aging processes. Given the ever-increasing availability of paired genomic and transcriptomic data, we anticipate this new approach to be a starting point for more comprehensive computational scans for transposon transcriptional regulators.
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Affiliation(s)
- Juan I. Bravo
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
- Graduate program in the Biology of Aging, University of Southern California, Los Angeles, CA 90089, USA
| | - Chanelle R. Mizrahi
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
- USC Gerontology Enriching MSTEM to Enhance Diversity in Aging Program, University of Southern California, Los Angeles, CA 90089, USA
| | - Seungsoo Kim
- Department of Obstetrics and Gynecology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Lucia Zhang
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
- Quantitative and Computational Biology Department, USC Dornsife College of Letters, Arts and Sciences, Los Angeles, CA 90089, USA
| | - Yousin Suh
- Department of Obstetrics and Gynecology, Columbia University Irving Medical Center, New York, NY 10032, USA
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Bérénice A. Benayoun
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
- Molecular and Computational Biology Department, USC Dornsife College of Letters, Arts and Sciences, Los Angeles, CA 90089, USA
- Biochemistry and Molecular Medicine Department, USC Keck School of Medicine, Los Angeles, CA 90089, USA
- USC Norris Comprehensive Cancer Center, Epigenetics and Gene Regulation, Los Angeles, CA 90089, USA
- USC Stem Cell Initiative, Los Angeles, CA 90089, USA
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Arora A, Kolberg JE, Srinivasachar Badarinarayan S, Savytska N, Munot D, Müller M, Krchlíková V, Sauter D, Bansal V. SARS-CoV-2 infection induces epigenetic changes in the LTR69 subfamily of endogenous retroviruses. Mob DNA 2023; 14:11. [PMID: 37667401 PMCID: PMC10476400 DOI: 10.1186/s13100-023-00299-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 08/21/2023] [Indexed: 09/06/2023] Open
Abstract
Accumulating evidence suggests that endogenous retroviruses (ERVs) play an important role in the host response to infection and the development of disease. By analyzing ChIP-sequencing data sets, we show that SARS-CoV-2 infection induces H3K27 acetylation of several loci within the LTR69 subfamily of ERVs. Using functional assays, we identified one SARS-CoV-2-activated LTR69 locus, termed Dup69, which exhibits regulatory activity and is responsive to the transcription factors IRF3 and p65/RELA. LTR69_Dup69 is located about 500 bp upstream of a long non-coding RNA gene (ENSG00000289418) and within the PTPRN2 gene encoding a diabetes-associated autoantigen. Both ENSG00000289418 and PTPRN2 showed a significant increase in expression upon SARS-CoV-2 infection. Thus, our study sheds light on the interplay of exogenous with endogenous viruses and helps to understand how ERVs regulate gene expression during infection.
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Affiliation(s)
- Ankit Arora
- Institute for Stem Cell Science and Regenerative Medicine, Bengaluru, India.
| | - Jan Eric Kolberg
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Smitha Srinivasachar Badarinarayan
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA
| | - Natalia Savytska
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Daksha Munot
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Martin Müller
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Veronika Krchlíková
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Daniel Sauter
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Vikas Bansal
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany.
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Expression of down-regulated ERV LTR elements associates with immune activation in human small-cell lung cancers. Mob DNA 2023; 14:2. [PMID: 36918931 PMCID: PMC10012523 DOI: 10.1186/s13100-023-00290-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 02/27/2023] [Indexed: 03/16/2023] Open
Abstract
Small-cell lung cancer (SCLC) is an aggressive cancer characterized by immunosuppressive features leading to poor responses to current immunotherapies. Activation of transposable elements (TE) can trigger an innate immune response, which can synergize with immunotherapeutic protocols in patients. However, TE activity in relation to immune gene response is not fully known in human SCLC. Here, we compared TE expression in 104 human SCLC and 24 normal tissues and established their involvement in innate immune responses. We observed that different intergenic TEs, mainly endogenous retroviral (ERV) families, are deregulated in SCLC. Similarly to other cancers, we detected a subset of LTRs that correlate with innate immune gene signatures and cytosolic RNA sensors, such as RIG-I. These LTRs are downregulated in SCLC tumors vs. normal tissues, and are mainly located at transcriptional repressed regions, marked with H3K4me2 in different cell lines. Analyses of different genomic datasets show that chromatin repression is likely due to de-methylase LSD1 activity. Moreover, high expression levels of ERV LTRs predict a better survival upon chemotherapy of SCLC patients. The findings reveal a specific pattern of TE-mediated activation of innate immune genes in SCLC, which can be exploited to establish more effective immunotherapeutic combinations.
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