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Xiong J, Xu Y, Wang N, Wang S, Zhang Y, Lu S, Zhang X, Liang X, Liu C, Jiang Q, Xu J, Qian Q, Zhou P, Yin L, Liu F, Chen S, Yin S, Liu J. Obstructive Sleep Apnea Syndrome Exacerbates NASH Progression via Selective Autophagy-Mediated Eepd1 Degradation. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2405955. [PMID: 38924647 DOI: 10.1002/advs.202405955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Indexed: 06/28/2024]
Abstract
Obstructive sleep apnea syndrome (OSAS), characterized by chronic intermittent hypoxia (CIH), is an independent risk factor for aggravating non-alcoholic steatohepatitis (NASH). The prevailing mouse model employed in CIH research is inadequate for the comprehensive exploration of the impact of CIH on NASH development due to reduced food intake observed in CIH-exposed mice, which deviates from human responses. To address this issue, a pair-feeding investigation with CIH-exposed and normoxia-exposed mice is conducted. It is revealed that CIH exposure aggravates DNA damage, leading to hepatic fibrosis and inflammation. The analysis of genome-wide association study (GWAS) data also discloses the association between Eepd1, a DNA repair enzyme, and OSAS. Furthermore, it is revealed that CIH triggered selective autophagy, leading to the autophagic degradation of Eepd1, thereby exacerbating DNA damage in hepatocytes. Notably, Eepd1 liver-specific knockout mice exhibit aggravated hepatic DNA damage and further progression of NASH. To identify a therapeutic approach for CIH-induced NASH, a drug screening is conducted and it is found that Retigabine dihydrochloride suppresses CIH-mediated Eepd1 degradation, leading to alleviated DNA damage in hepatocytes. These findings imply that targeting CIH-mediated Eepd1 degradation can be an adjunctive approach in the treatment of NASH exacerbated by OSAS.
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Affiliation(s)
- Jie Xiong
- Shanghai Diabetes Institute, Department of Endocrinology and Metabolism, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Ying Xu
- Shanghai Diabetes Institute, Department of Endocrinology and Metabolism, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Ning Wang
- Shanghai Diabetes Institute, Department of Endocrinology and Metabolism, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Shengming Wang
- Department of Otolaryngology Head and Neck Surgery & Shanghai, Key Laboratory of Sleep Disordered Breathing & Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Yao Zhang
- Shanghai Diabetes Institute, Department of Endocrinology and Metabolism, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Sijia Lu
- Shanghai Diabetes Institute, Department of Endocrinology and Metabolism, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Xiaoman Zhang
- Department of Otolaryngology Head and Neck Surgery & Shanghai, Key Laboratory of Sleep Disordered Breathing & Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | | | - Chuchu Liu
- Shanghai Diabetes Institute, Department of Endocrinology and Metabolism, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Quanxin Jiang
- Shanghai Diabetes Institute, Department of Endocrinology and Metabolism, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Junting Xu
- Shanghai Diabetes Institute, Department of Endocrinology and Metabolism, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Qiqi Qian
- Shanghai Diabetes Institute, Department of Endocrinology and Metabolism, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Peihui Zhou
- Shanghai Diabetes Institute, Department of Endocrinology and Metabolism, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Limin Yin
- Shanghai Diabetes Institute, Department of Endocrinology and Metabolism, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Feng Liu
- Department of Otolaryngology Head and Neck Surgery & Shanghai, Key Laboratory of Sleep Disordered Breathing & Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Suzhen Chen
- Shanghai Diabetes Institute, Department of Endocrinology and Metabolism, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Shankai Yin
- Department of Otolaryngology Head and Neck Surgery & Shanghai, Key Laboratory of Sleep Disordered Breathing & Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Junli Liu
- Shanghai Diabetes Institute, Department of Endocrinology and Metabolism, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
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Nickoloff JA, Jaiswal AS, Sharma N, Williamson EA, Tran MT, Arris D, Yang M, Hromas R. Cellular Responses to Widespread DNA Replication Stress. Int J Mol Sci 2023; 24:16903. [PMID: 38069223 PMCID: PMC10707325 DOI: 10.3390/ijms242316903] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/22/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
Replicative DNA polymerases are blocked by nearly all types of DNA damage. The resulting DNA replication stress threatens genome stability. DNA replication stress is also caused by depletion of nucleotide pools, DNA polymerase inhibitors, and DNA sequences or structures that are difficult to replicate. Replication stress triggers complex cellular responses that include cell cycle arrest, replication fork collapse to one-ended DNA double-strand breaks, induction of DNA repair, and programmed cell death after excessive damage. Replication stress caused by specific structures (e.g., G-rich sequences that form G-quadruplexes) is localized but occurs during the S phase of every cell division. This review focuses on cellular responses to widespread stress such as that caused by random DNA damage, DNA polymerase inhibition/nucleotide pool depletion, and R-loops. Another form of global replication stress is seen in cancer cells and is termed oncogenic stress, reflecting dysregulated replication origin firing and/or replication fork progression. Replication stress responses are often dysregulated in cancer cells, and this too contributes to ongoing genome instability that can drive cancer progression. Nucleases play critical roles in replication stress responses, including MUS81, EEPD1, Metnase, CtIP, MRE11, EXO1, DNA2-BLM, SLX1-SLX4, XPF-ERCC1-SLX4, Artemis, XPG, FEN1, and TATDN2. Several of these nucleases cleave branched DNA structures at stressed replication forks to promote repair and restart of these forks. We recently defined roles for EEPD1 in restarting stressed replication forks after oxidative DNA damage, and for TATDN2 in mitigating replication stress caused by R-loop accumulation in BRCA1-defective cells. We also discuss how insights into biological responses to genome-wide replication stress can inform novel cancer treatment strategies that exploit synthetic lethal relationships among replication stress response factors.
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Affiliation(s)
- Jac A. Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
| | - Aruna S. Jaiswal
- Department of Medicine and the Mays Cancer Center, The University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA; (A.S.J.); (M.T.T.); (R.H.)
| | - Neelam Sharma
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
| | - Elizabeth A. Williamson
- Department of Medicine and the Mays Cancer Center, The University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA; (A.S.J.); (M.T.T.); (R.H.)
| | - Manh T. Tran
- Department of Medicine and the Mays Cancer Center, The University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA; (A.S.J.); (M.T.T.); (R.H.)
| | - Dominic Arris
- Department of Medicine and the Mays Cancer Center, The University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA; (A.S.J.); (M.T.T.); (R.H.)
| | - Ming Yang
- Department of Medicine and the Mays Cancer Center, The University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA; (A.S.J.); (M.T.T.); (R.H.)
| | - Robert Hromas
- Department of Medicine and the Mays Cancer Center, The University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA; (A.S.J.); (M.T.T.); (R.H.)
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Jaiswal AS, Kim HS, Schärer OD, Sharma N, Williamson E, Srinivasan G, Phillips L, Kong K, Arya S, Misra A, Dutta A, Gupta Y, Walter C, Burma S, Narayan S, Sung P, Nickoloff J, Hromas R. EEPD1 promotes repair of oxidatively-stressed replication forks. NAR Cancer 2023; 5:zcac044. [PMID: 36683914 PMCID: PMC9846428 DOI: 10.1093/narcan/zcac044] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 11/22/2022] [Accepted: 12/14/2022] [Indexed: 01/19/2023] Open
Abstract
Unrepaired oxidatively-stressed replication forks can lead to chromosomal instability and neoplastic transformation or cell death. To meet these challenges cells have evolved a robust mechanism to repair oxidative genomic DNA damage through the base excision repair (BER) pathway, but less is known about repair of oxidative damage at replication forks. We found that depletion or genetic deletion of EEPD1 decreases clonogenic cell survival after oxidative DNA damage. We demonstrate that EEPD1 is recruited to replication forks stressed by oxidative damage induced by H2O2 and that EEPD1 promotes replication fork repair and restart and decreases chromosomal abnormalities after such damage. EEPD1 binds to abasic DNA structures and promotes resolution of genomic abasic sites after oxidative stress. We further observed that restoration of expression of EEPD1 via expression vector transfection restores cell survival and suppresses chromosomal abnormalities induced by oxidative stress in EEPD1-depleted cells. Consistent with this, we found that EEPD1 preserves replication fork integrity by preventing oxidatively-stressed unrepaired fork fusion, thereby decreasing chromosome instability and mitotic abnormalities. Our results indicate a novel role for EEPD1 in replication fork preservation and maintenance of chromosomal stability during oxidative stress.
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Affiliation(s)
- Aruna S Jaiswal
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Hyun-Suk Kim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Republic of Korea
| | - Orlando D Schärer
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Republic of Korea
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Neelam Sharma
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Elizabeth A Williamson
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Gayathri Srinivasan
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Linda Phillips
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Kimi Kong
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Shailee Arya
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Anurag Misra
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Arijit Dutta
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Yogesh Gupta
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Christi A Walter
- Department of Cell Systems and Anatomy, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Sandeep Burma
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA
- Department of Neurosurgery, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Satya Narayan
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, FL 32610, USA
| | - Patrick Sung
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Jac A Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Robert Hromas
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX 78229, USA
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Dey A, Flajšhans M, Pšenička M, Gazo I. DNA repair genes play a variety of roles in the development of fish embryos. Front Cell Dev Biol 2023; 11:1119229. [PMID: 36936683 PMCID: PMC10014602 DOI: 10.3389/fcell.2023.1119229] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 02/14/2023] [Indexed: 03/08/2023] Open
Abstract
Embryogenesis is one of the most important life stages because it determines an organism's healthy growth. However, embryos of externally fertilizing species, such as most fish, are directly exposed to the environment during development and may be threatened by DNA damaging factors (pollutants, UV, reactive oxygen species). To counteract the negative effects of DNA fragmentation, fish embryos evolved complex damage response pathways. DNA repair pathways have been extensively studied in some fish species, such as zebrafish (Danio rerio). Our literature review, on the other hand, revealed a paucity of knowledge about DNA damage response and repair in non-model aquaculture fish species. Further, several pieces of evidence underlie the additional role of DNA repair genes and proteins in organogenesis, spatiotemporal localization in different tissue, and its indispensability for normal embryo development. In this review, we will summarize features of different DNA repair pathways in course of fish embryo development. We describe how the expression of DNA repair genes and proteins is regulated during development, their organogenetic roles, and how the expression of DNA repair genes changes in response to genotoxic stress. This will aid in addressing the link between genotoxic stress and embryo phenotype. Furthermore, available data indicate that embryos can repair damaged DNA, but the effects of early-life stress may manifest later in life as behavioral changes, neoplasia, or neurodegeneration. Overall, we conclude that more research on DNA repair in fish embryos is needed.
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Analysis on the desert adaptability of indigenous sheep in the southern edge of Taklimakan Desert. Sci Rep 2022; 12:12264. [PMID: 35851076 PMCID: PMC9293982 DOI: 10.1038/s41598-022-15986-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 07/04/2022] [Indexed: 11/25/2022] Open
Abstract
The southern margin of the Taklimakan Desert is characterized by low rainfall, heavy sandstorms, sparse vegetation and harsh ecological environment. The indigenous sheep in this area are rich in resources, with the advantages of perennial estrus and good resistance to stress in most sheep. Exploring the molecular markers of livestock adaptability in this environment will provide the molecular basis for breeding research to cope with extreme future changes in the desert environment. In this study, we analyzed the population genetic structure and linkage imbalance of five sheep breeds with three different agricultural geographic characteristics using four complementary genomic selection signals: fixation index (FST), cross-population extended haplotype homozygosity (xp-EHH), Rsb (extended haplotype homozygosity between-populations) and iHS (integrated haplotype homozygosity score). We used Illumina Ovine SNP 50K Genotyping BeadChip Array, and gene annotation and enrichment analysis were performed on selected regions of the obtained genome. The ovary of Qira Black sheep (Follicular phase, Luteal phase, 30th day of pregnancy, 45th day of pregnancy) was collected, and the differentially expressed genes were screened by transcriptomic sequencing. Genome-wide selective sweep results and transcriptome data were combined for association analysis to obtain candidate genes associated with perennial estrus and stable reproduction. In order to verify the significance of the results, 15 resulting genes were randomly selected for fluorescence quantitative analysis. The results showed that Dolang sheep and Qira Black sheep evolved from Kazak sheep. Linkage disequilibrium analysis showed that the decay rate of sheep breeds in the Taklimakan Desert was higher than that in Yili grassland. The signals of FST, xp-EHH, Rsb and iHS detected 526, 332, 308 and 408 genes, respectively, under the threshold of 1% and 17 overlapping genes under the threshold of 5%. A total of 29 genes were detected in association analysis of whole-genome and transcriptome data. This study reveals the genetic mechanism of perennial estrus and environmental adaptability of indigenous sheep breeds in the Taklimakan Desert. It provides a theoretical basis for the conservation and exploitation of genetic resources of indigenous sheep breeds in extreme desert environment. This provides a new perspective for the quick adaptation of sheep and other mammals to extreme environments and future climate changes.
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Nickoloff JA, Sharma N, Taylor L, Allen SJ, Hromas R. Nucleases and Co-Factors in DNA Replication Stress Responses. DNA 2022; 2:68-85. [PMID: 36203968 PMCID: PMC9534323 DOI: 10.3390/dna2010006] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
DNA replication stress is a constant threat that cells must manage to proliferate and maintain genome integrity. DNA replication stress responses, a subset of the broader DNA damage response (DDR), operate when the DNA replication machinery (replisome) is blocked or replication forks collapse during S phase. There are many sources of replication stress, such as DNA lesions caused by endogenous and exogenous agents including commonly used cancer therapeutics, and difficult-to-replicate DNA sequences comprising fragile sites, G-quadraplex DNA, hairpins at trinucleotide repeats, and telomeres. Replication stress is also a consequence of conflicts between opposing transcription and replication, and oncogenic stress which dysregulates replication origin firing and fork progression. Cells initially respond to replication stress by protecting blocked replisomes, but if the offending problem (e.g., DNA damage) is not bypassed or resolved in a timely manner, forks may be cleaved by nucleases, inducing a DNA double-strand break (DSB) and providing a means to accurately restart stalled forks via homologous recombination. However, DSBs pose their own risks to genome stability if left unrepaired or misrepaired. Here we focus on replication stress response systems, comprising DDR signaling, fork protection, and fork processing by nucleases that promote fork repair and restart. Replication stress nucleases include MUS81, EEPD1, Metnase, CtIP, MRE11, EXO1, DNA2-BLM, SLX1-SLX4, XPF-ERCC1-SLX4, Artemis, XPG, and FEN1. Replication stress factors are important in cancer etiology as suppressors of genome instability associated with oncogenic mutations, and as potential cancer therapy targets to enhance the efficacy of chemo- and radiotherapeutics.
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Affiliation(s)
- Jac A. Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
| | - Neelam Sharma
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
| | - Lynn Taylor
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
| | - Sage J. Allen
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
| | - Robert Hromas
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX 78229, USA
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Nickoloff JA, Sharma N, Taylor L, Allen SJ, Lee SH, Hromas R. Metnase and EEPD1: DNA Repair Functions and Potential Targets in Cancer Therapy. Front Oncol 2022; 12:808757. [PMID: 35155245 PMCID: PMC8831698 DOI: 10.3389/fonc.2022.808757] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 01/12/2022] [Indexed: 12/30/2022] Open
Abstract
Cells respond to DNA damage by activating signaling and DNA repair systems, described as the DNA damage response (DDR). Clarifying DDR pathways and their dysregulation in cancer are important for understanding cancer etiology, how cancer cells exploit the DDR to survive endogenous and treatment-related stress, and to identify DDR targets as therapeutic targets. Cancer is often treated with genotoxic chemicals and/or ionizing radiation. These agents are cytotoxic because they induce DNA double-strand breaks (DSBs) directly, or indirectly by inducing replication stress which causes replication fork collapse to DSBs. EEPD1 and Metnase are structure-specific nucleases, and Metnase is also a protein methyl transferase that methylates histone H3 and itself. EEPD1 and Metnase promote repair of frank, two-ended DSBs, and both promote the timely and accurate restart of replication forks that have collapsed to single-ended DSBs. In addition to its roles in HR, Metnase also promotes DSB repair by classical non-homologous recombination, and chromosome decatenation mediated by TopoIIα. Although mutations in Metnase and EEPD1 are not common in cancer, both proteins are frequently overexpressed, which may help tumor cells manage oncogenic stress or confer resistance to therapeutics. Here we focus on Metnase and EEPD1 DNA repair pathways, and discuss opportunities for targeting these pathways to enhance cancer therapy.
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Affiliation(s)
- Jac A Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States
| | - Neelam Sharma
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States
| | - Lynn Taylor
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States
| | - Sage J Allen
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States
| | - Suk-Hee Lee
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Robert Hromas
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX, United States
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Nickoloff JA, Sharma N, Taylor L, Allen SJ, Hromas R. The Safe Path at the Fork: Ensuring Replication-Associated DNA Double-Strand Breaks are Repaired by Homologous Recombination. Front Genet 2021; 12:748033. [PMID: 34646312 PMCID: PMC8502867 DOI: 10.3389/fgene.2021.748033] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/14/2021] [Indexed: 01/15/2023] Open
Abstract
Cells must replicate and segregate their DNA to daughter cells accurately to maintain genome stability and prevent cancer. DNA replication is usually fast and accurate, with intrinsic (proofreading) and extrinsic (mismatch repair) error-correction systems. However, replication forks slow or stop when they encounter DNA lesions, natural pause sites, and difficult-to-replicate sequences, or when cells are treated with DNA polymerase inhibitors or hydroxyurea, which depletes nucleotide pools. These challenges are termed replication stress, to which cells respond by activating DNA damage response signaling pathways that delay cell cycle progression, stimulate repair and replication fork restart, or induce apoptosis. Stressed forks are managed by rescue from adjacent forks, repriming, translesion synthesis, template switching, and fork reversal which produces a single-ended double-strand break (seDSB). Stressed forks also collapse to seDSBs when they encounter single-strand nicks or are cleaved by structure-specific nucleases. Reversed and cleaved forks can be restarted by homologous recombination (HR), but seDSBs pose risks of mis-rejoining by non-homologous end-joining (NHEJ) to other DSBs, causing genome rearrangements. HR requires resection of broken ends to create 3' single-stranded DNA for RAD51 recombinase loading, and resected ends are refractory to repair by NHEJ. This Mini Review highlights mechanisms that help maintain genome stability by promoting resection of seDSBs and accurate fork restart by HR.
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Affiliation(s)
- Jac A Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO, United States
| | - Neelam Sharma
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO, United States
| | - Lynn Taylor
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO, United States
| | - Sage J Allen
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO, United States
| | - Robert Hromas
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX, United States
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Sun Y, Wang J, Ma Y, Li J, Sun X, Zhao X, Shi X, Hu Y, Qu F, Zhang X. Radiation induces NORAD expression to promote ESCC radiotherapy resistance via EEPD1/ATR/Chk1 signalling and by inhibiting pri-miR-199a1 processing and the exosomal transfer of miR-199a-5p. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2021; 40:306. [PMID: 34587992 PMCID: PMC8479908 DOI: 10.1186/s13046-021-02084-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 08/24/2021] [Indexed: 12/27/2022]
Abstract
BACKGROUND Radioresistance, a poorly understood phenomenon, results in the failure of radiotherapy and subsequent local recurrence, threatening a large proportion of patients with ESCC. To date, lncRNAs have been reported to be involved in diverse biological processes, including radioresistance. METHODS FISH and qRT-PCR were adopted to examine the expression and localization of lncRNA-NORAD, pri-miR-199a1 and miR-199a-5p. Electron microscopy and nanoparticle tracking analysis (NTA) were conducted to observe and identify exosomes. High-throughput microRNAs sequencing and TMT mass spectrometry were performed to identify the functional miRNA and proteins. A series of in vitro and in vivo experiments were performed to investigate the biological effect of NORAD. ChIP, RIP-qPCR, co-IP and dual-luciferase reporter assays were conducted to explore the interaction of related RNAs and proteins. RESULTS We show here that DNA damage activates the noncoding RNA NORAD, which is critical for ESCC radioresistance. NORAD was expressed at high levels in radioresistant ESCC cells. Radiation treatment promotes NORAD expression by enhancing H3K4me2 enrichment in its sequence. NORAD knockdown cells exhibit significant hypersensitivity to radiation in vivo and in vitro. NORAD is required to initiate the repair and restart of stalled forks, G2 cycle arrest and homologous recombination repair upon radiation treatment. Mechanistically, NORAD inhibits miR-199a-5p expression by competitively binding PUM1 from pri-miR-199a1, inhibiting the processing of pri-miR-199a1. Mature miR-199a-5p in NORAD knockdown cells is packaged into exosomes; miR-199a-5p restores the radiosensitivity of radioresistant cells by targeting EEPD1 and then inhibiting the ATR/Chk1 signalling pathway. Simultaneously, NORAD knockdown inhibits the ubiquitination of PD-L1, leading to a better response to radiation and anti-PD-1 treatment in a mouse model. CONCLUSIONS Based on the findings of this study, lncRNA-NORAD represents a potential treatment target for improving the efficiency of immunotherapy in combination with radiation in ESCC.
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Affiliation(s)
- Yuchen Sun
- The Department of Radiation Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, Shaanxi, 710061, People's Republic of China
| | - Jizhao Wang
- The Department of Thoracic Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, Shaanxi, 710061, People's Republic of China
| | - Yuan Ma
- The Department of Radiation Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, Shaanxi, 710061, People's Republic of China
| | - Jing Li
- The Department of Radiation Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, Shaanxi, 710061, People's Republic of China
| | - Xuanzi Sun
- The Department of Radiation Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, Shaanxi, 710061, People's Republic of China
| | - Xu Zhao
- The Department of Radiation Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, Shaanxi, 710061, People's Republic of China
| | - Xiaobo Shi
- The Department of Radiation Oncology, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 XiWu Road, Xi'an, Shaanxi, 710004, People's Republic of China
| | - Yunfeng Hu
- The Department of Radiation Oncology, Yanan University Affiliated Hospital, 157 Beida Road, Yanan, Shannxi, 716099, People's Republic of China
| | - Fengyi Qu
- The Department of Radiation Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, Shaanxi, 710061, People's Republic of China
| | - Xiaozhi Zhang
- The Department of Radiation Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, Shaanxi, 710061, People's Republic of China.
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10
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Nickoloff JA, Sharma N, Allen CP, Taylor L, Allen SJ, Jaiswal AS, Hromas R. Roles of homologous recombination in response to ionizing radiation-induced DNA damage. Int J Radiat Biol 2021; 99:903-914. [PMID: 34283012 PMCID: PMC9629169 DOI: 10.1080/09553002.2021.1956001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/04/2021] [Accepted: 07/05/2021] [Indexed: 02/06/2023]
Abstract
PURPOSE Ionizing radiation induces a vast array of DNA lesions including base damage, and single- and double-strand breaks (SSB, DSB). DSBs are among the most cytotoxic lesions, and mis-repair causes small- and large-scale genome alterations that can contribute to carcinogenesis. Indeed, ionizing radiation is a 'complete' carcinogen. DSBs arise immediately after irradiation, termed 'frank DSBs,' as well as several hours later in a replication-dependent manner, termed 'secondary' or 'replication-dependent DSBs. DSBs resulting from replication fork collapse are single-ended and thus pose a distinct problem from two-ended, frank DSBs. DSBs are repaired by error-prone nonhomologous end-joining (NHEJ), or generally error-free homologous recombination (HR), each with sub-pathways. Clarifying how these pathways operate in normal and tumor cells is critical to increasing tumor control and minimizing side effects during radiotherapy. CONCLUSIONS The choice between NHEJ and HR is regulated during the cell cycle and by other factors. DSB repair pathways are major contributors to cell survival after ionizing radiation, including tumor-resistance to radiotherapy. Several nucleases are important for HR-mediated repair of replication-dependent DSBs and thus replication fork restart. These include three structure-specific nucleases, the 3' MUS81 nuclease, and two 5' nucleases, EEPD1 and Metnase, as well as three end-resection nucleases, MRE11, EXO1, and DNA2. The three structure-specific nucleases evolved at very different times, suggesting incremental acceleration of replication fork restart to limit toxic HR intermediates and genome instability as genomes increased in size during evolution, including the gain of large numbers of HR-prone repetitive elements. Ionizing radiation also induces delayed effects, observed days to weeks after exposure, including delayed cell death and delayed HR. In this review we highlight the roles of HR in cellular responses to ionizing radiation, and discuss the importance of HR as an exploitable target for cancer radiotherapy.
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Affiliation(s)
- Jac A. Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
| | - Neelam Sharma
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
| | - Christopher P. Allen
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
- Department of Microbiology, Immunology and Pathology, Flow Cytometry and Cell Sorting Facility, Colorado State University, Fort Collins, CO, USA
| | - Lynn Taylor
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
| | - Sage J. Allen
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
| | - Aruna S. Jaiswal
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX, USA
| | - Robert Hromas
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX, USA
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11
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Munisha M, Schimenti JC. Genome maintenance during embryogenesis. DNA Repair (Amst) 2021; 106:103195. [PMID: 34358805 DOI: 10.1016/j.dnarep.2021.103195] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 07/26/2021] [Accepted: 07/27/2021] [Indexed: 12/25/2022]
Abstract
Genome maintenance during embryogenesis is critical, because defects during this period can be perpetuated and thus have a long-term impact on individual's health and longevity. Nevertheless, genome instability is normal during certain aspects of embryonic development, indicating that there is a balance between the exigencies of timely cell proliferation and mutation prevention. In particular, early embryos possess unique cellular and molecular features that underscore the challenge of having an appropriate balance. Here, we discuss genome instability during embryonic development, the mechanisms used in various cell compartments to manage genomic stress and address outstanding questions regarding the balance between genome maintenance mechanisms in key cell types that are important for adulthood and progeny.
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Affiliation(s)
- Mumingjiang Munisha
- Dept. of Biomedical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY 14853, United States
| | - John C Schimenti
- Dept. of Biomedical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY 14853, United States.
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12
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Integrated transcriptomic and genomic analysis improves prediction of complete remission and survival in elderly patients with acute myeloid leukemia. Blood Cancer J 2020; 10:67. [PMID: 32527994 PMCID: PMC7289793 DOI: 10.1038/s41408-020-0332-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 05/21/2020] [Accepted: 05/26/2020] [Indexed: 01/18/2023] Open
Abstract
Relevant molecular tools for treatment stratification of patients ≥65 years with acute myeloid leukemia (AML) are lacking. We combined clinical data with targeted DNA- and full RNA-sequencing of 182 intensively and palliatively treated patients to predict complete remission (CR) and survival in AML patients ≥65 years. Intensively treated patients with NPM1 and IDH2R172 mutations had longer overall survival (OS), whereas mutated TP53 conferred lower CR rates and shorter OS. FLT3-ITD and TP53 mutations predicted worse OS in palliatively treated patients. Gene expression levels most predictive of CR were combined with somatic mutations for an integrated risk stratification that we externally validated using the beatAML cohort. We defined a high-risk group with a CR rate of 20% in patients with mutated TP53, compared to 97% CR in low-risk patients defined by high expression of ZBTB7A and EEPD1 without TP53 mutations. Patients without these criteria had a CR rate of 54% (intermediate risk). The difference in CR rates translated into significant OS differences that outperformed ELN stratification for OS prediction. The results suggest that an integrated molecular risk stratification can improve prediction of CR and OS and could be used to guide treatment in elderly AML patients.
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13
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Sharma N, Speed MC, Allen CP, Maranon DG, Williamson E, Singh S, Hromas R, Nickoloff JA. Distinct roles of structure-specific endonucleases EEPD1 and Metnase in replication stress responses. NAR Cancer 2020; 2:zcaa008. [PMID: 32743552 PMCID: PMC7380491 DOI: 10.1093/narcan/zcaa008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 05/20/2020] [Accepted: 05/31/2020] [Indexed: 12/16/2022] Open
Abstract
Accurate DNA replication and segregation are critical for maintaining genome integrity and suppressing cancer. Metnase and EEPD1 are DNA damage response (DDR) proteins frequently dysregulated in cancer and implicated in cancer etiology and tumor response to genotoxic chemo- and radiotherapy. Here, we examine the DDR in human cell lines with CRISPR/Cas9 knockout of Metnase or EEPD1. The knockout cell lines exhibit slightly slower growth rates, significant hypersensitivity to replication stress, increased genome instability and distinct alterations in DDR signaling. Metnase and EEPD1 are structure-specific nucleases. EEPD1 is recruited to and cleaves stalled forks to initiate fork restart by homologous recombination. Here, we demonstrate that Metnase is also recruited to stalled forks where it appears to dimethylate histone H3 lysine 36 (H3K36me2), raising the possibility that H3K36me2 promotes DDR factor recruitment or limits nucleosome eviction to protect forks from nucleolytic attack. We show that stalled forks are cleaved normally in the absence of Metnase, an important and novel result because a prior study indicated that Metnase nuclease is important for timely fork restart. A double knockout was as sensitive to etoposide as either single knockout, suggesting a degree of epistasis between Metnase and EEPD1. We propose that EEPD1 initiates fork restart by cleaving stalled forks, and that Metnase may promote fork restart by processing homologous recombination intermediates and/or inducing H3K36me2 to recruit DDR factors. By accelerating fork restart, Metnase and EEPD1 reduce the chance that stalled replication forks will adopt toxic or genome-destabilizing structures, preventing genome instability and cancer. Metnase and EEPD1 are overexpressed in some cancers and thus may also promote resistance to genotoxic therapeutics.
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Affiliation(s)
- Neelam Sharma
- Department of Environmental and Radiological Health Sciences, Colorado State University, 1618 Campus Delivery, Fort Collins, CO 80523-1618, USA
| | - Michael C Speed
- Department of Environmental and Radiological Health Sciences, Colorado State University, 1618 Campus Delivery, Fort Collins, CO 80523-1618, USA
| | - Christopher P Allen
- Department of Microbiology, Immunology, and Pathology, Colorado State University, 1601Campus Delivery, Fort Collins, CO 80523-1601, USA
| | - David G Maranon
- Department of Environmental and Radiological Health Sciences, Colorado State University, 1618 Campus Delivery, Fort Collins, CO 80523-1618, USA
| | - Elizabeth Williamson
- Division of Hematology and Medical Oncology, Department of Medicine, University of Texas HealthScience Center, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Sudha Singh
- Division of Hematology and Medical Oncology, Department of Medicine, University of Texas HealthScience Center, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Robert Hromas
- Division of Hematology and Medical Oncology, Department of Medicine, University of Texas HealthScience Center, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Jac A Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, 1618 Campus Delivery, Fort Collins, CO 80523-1618, USA
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14
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Kermi C, Aze A, Maiorano D. Preserving Genome Integrity During the Early Embryonic DNA Replication Cycles. Genes (Basel) 2019; 10:genes10050398. [PMID: 31137726 PMCID: PMC6563053 DOI: 10.3390/genes10050398] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 05/15/2019] [Indexed: 02/06/2023] Open
Abstract
During the very early stages of embryonic development chromosome replication occurs under rather challenging conditions, including a very short cell cycle, absence of transcription, a relaxed DNA damage response and, in certain animal species, a highly contracted S-phase. This raises the puzzling question of how the genome can be faithfully replicated in such a peculiar metabolic context. Recent studies have provided new insights into this issue, and unveiled that embryos are prone to accumulate genetic and genomic alterations, most likely due to restricted cellular functions, in particular reduced DNA synthesis quality control. These findings may explain the low rate of successful development in mammals and the occurrence of diseases, such as abnormal developmental features and cancer. In this review, we will discuss recent findings in this field and put forward perspectives to further study this fascinating question.
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Affiliation(s)
- Chames Kermi
- Laboratoire Surveillance et Stabilité du Génome, Institut de Génétique Humaine, UMR9002, CNRS, Université de Montpellier, 34090 Montpellier, France.
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA.
| | - Antoine Aze
- Laboratoire Surveillance et Stabilité du Génome, Institut de Génétique Humaine, UMR9002, CNRS, Université de Montpellier, 34090 Montpellier, France.
| | - Domenico Maiorano
- Laboratoire Surveillance et Stabilité du Génome, Institut de Génétique Humaine, UMR9002, CNRS, Université de Montpellier, 34090 Montpellier, France.
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15
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Hromas R, Kim HS, Sidhu G, Williamson E, Jaiswal A, Totterdale TA, Nole J, Lee SH, Nickoloff JA, Kong KY. The endonuclease EEPD1 mediates synthetic lethality in RAD52-depleted BRCA1 mutant breast cancer cells. Breast Cancer Res 2017; 19:122. [PMID: 29145865 PMCID: PMC5693420 DOI: 10.1186/s13058-017-0912-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Accepted: 10/30/2017] [Indexed: 02/06/2023] Open
Abstract
Background Proper repair and restart of stressed replication forks requires intact homologous recombination (HR). HR at stressed replication forks can be initiated by the 5′ endonuclease EEPD1, which cleaves the stalled replication fork. Inherited or acquired defects in HR, such as mutations in breast cancer susceptibility protein-1 (BRCA1) or BRCA2, predispose to cancer, including breast and ovarian cancers. In order for these HR-deficient tumor cells to proliferate, they become addicted to a bypass replication fork repair pathway mediated by radiation repair protein 52 (RAD52). Depleting RAD52 can cause synthetic lethality in BRCA1/2 mutant cancers by an unknown molecular mechanism. Methods We hypothesized that cleavage of stressed replication forks by EEPD1 generates a fork repair intermediate that is toxic when HR-deficient cells cannot complete repair with the RAD52 bypass pathway. To test this hypothesis, we applied cell survival assays, immunofluorescence staining, DNA fiber and western blot analyses to look at the correlation between cell survival and genome integrity in control, EEPD1, RAD52 and EEPD1/RAD52 co-depletion BRCA1-deficient breast cancer cells. Results Our data show that depletion of EEPD1 suppresses synthetic lethality, genome instability, mitotic catastrophe, and hypersensitivity to stress of replication of RAD52-depleted, BRCA1 mutant breast cancer cells. Without HR and the RAD52-dependent backup pathway, the BRCA1 mutant cancer cells depleted of EEPD1 skew to the alternative non-homologous end-joining DNA repair pathway for survival. Conclusion This study indicates that the mechanism of synthetic lethality in RAD52-depleted BRCA1 mutant cancer cells depends on the endonuclease EEPD1. The data imply that EEPD1 cleavage of stressed replication forks may result in a toxic intermediate when replication fork repair cannot be completed. Electronic supplementary material The online version of this article (doi:10.1186/s13058-017-0912-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Robert Hromas
- Department of Medicine and the Cancer Center, University of Florida Health, 1600 SW Archer Rd, Gainesville, FL, 32610, USA.
| | - Hyun-Suk Kim
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Gurjit Sidhu
- Department of Medicine and the Cancer Center, University of Florida Health, 1600 SW Archer Rd, Gainesville, FL, 32610, USA
| | - Elizabeth Williamson
- Department of Medicine and the Cancer Center, University of Florida Health, 1600 SW Archer Rd, Gainesville, FL, 32610, USA
| | - Aruna Jaiswal
- Department of Medicine and the Cancer Center, University of Florida Health, 1600 SW Archer Rd, Gainesville, FL, 32610, USA
| | - Taylor A Totterdale
- Department of Medicine and the Cancer Center, University of Florida Health, 1600 SW Archer Rd, Gainesville, FL, 32610, USA
| | - Jocelyn Nole
- Department of Medicine and the Cancer Center, University of Florida Health, 1600 SW Archer Rd, Gainesville, FL, 32610, USA
| | - Suk-Hee Lee
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Jac A Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, 80523, USA
| | - Kimi Y Kong
- Department of Medicine and the Cancer Center, University of Florida Health, 1600 SW Archer Rd, Gainesville, FL, 32610, USA.
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16
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Belkacemi T, Niermann A, Hofmann L, Wissenbach U, Birnbaumer L, Leidinger P, Backes C, Meese E, Keller A, Bai X, Scheller A, Kirchhoff F, Philipp SE, Weissgerber P, Flockerzi V, Beck A. TRPC1- and TRPC3-dependent Ca 2+ signaling in mouse cortical astrocytes affects injury-evoked astrogliosis in vivo. Glia 2017. [PMID: 28636132 DOI: 10.1002/glia.23180] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Following brain injury astrocytes change into a reactive state, proliferate and grow into the site of lesion, a process called astrogliosis, initiated and regulated by changes in cytoplasmic Ca2+ . Transient receptor potential canonical (TRPC) channels may contribute to Ca2+ influx but their presence and possible function in astrocytes is not known. By RT-PCR and RNA sequencing we identified transcripts of Trpc1, Trpc2, Trpc3, and Trpc4 in FACS-sorted glutamate aspartate transporter (GLAST)-positive cultured mouse cortical astrocytes and subcloned full-length Trpc1 and Trpc3 cDNAs from these cells. Ca2+ entry in cortical astrocytes depended on TRPC3 and was increased in the absence of Trpc1. After co-expression of Trpc1 and Trpc3 in HEK-293 cells both proteins co-immunoprecipitate and form functional heteromeric channels, with TRPC1 reducing TRPC3 activity. In vitro, lack of Trpc3 reduced astrocyte proliferation and migration whereas the TRPC3 gain-of-function moonwalker mutation and Trpc1 deficiency increased astrocyte migration. In vivo, astrogliosis and cortex edema following stab wound injury were reduced in Trpc3-/- but increased in Trpc1-/- mice. In summary, our results show a decisive contribution of TRPC3 to astrocyte Ca2+ signaling, which is even augmented in the absence of Trpc1, in particular following brain injury. Targeted therapies to reduce TRPC3 channel activity in astrocytes might therefore be beneficial in traumatic brain injury.
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Affiliation(s)
- Thabet Belkacemi
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Alexander Niermann
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Laura Hofmann
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Ulrich Wissenbach
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Lutz Birnbaumer
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, 27709, USA.,Institute of Biomedical Research (BIOMED), Catholic University of Argentina, Buenos Aires, C1107AFF, Argentina
| | | | - Christina Backes
- Klinische Bioinformatik, Universität des Saarlandes, Saarbrücken, 66123, Germany
| | - Eckart Meese
- Institut für Humangenetik, Homburg, 66421, Germany
| | - Andreas Keller
- Klinische Bioinformatik, Universität des Saarlandes, Saarbrücken, 66123, Germany
| | - Xianshu Bai
- Molekulare Physiologie, Universität des Saarlandes, Homburg, 66421, Germany
| | - Anja Scheller
- Molekulare Physiologie, Universität des Saarlandes, Homburg, 66421, Germany
| | - Frank Kirchhoff
- Molekulare Physiologie, Universität des Saarlandes, Homburg, 66421, Germany
| | - Stephan E Philipp
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Petra Weissgerber
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Veit Flockerzi
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Andreas Beck
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany.,Zentrum für Human- und Molekularbiologie, Homburg, 66421, Germany
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17
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Nelson JK, Koenis DS, Scheij S, Cook ECL, Moeton M, Santos A, Lobaccaro JMA, Baron S, Zelcer N. EEPD1 Is a Novel LXR Target Gene in Macrophages Which Regulates ABCA1 Abundance and Cholesterol Efflux. Arterioscler Thromb Vasc Biol 2017; 37:423-432. [PMID: 28082258 PMCID: PMC5321112 DOI: 10.1161/atvbaha.116.308434] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 01/02/2017] [Indexed: 11/16/2022]
Abstract
Supplemental Digital Content is available in the text. Objective— The sterol-responsive nuclear receptors, liver X receptors α (LXRα, NR1H3) and β (LXRβ, NR1H2), are key determinants of cellular cholesterol homeostasis. LXRs are activated under conditions of high cellular sterol load and induce expression of the cholesterol efflux transporters ABCA1 and ABCG1 to promote efflux of excess cellular cholesterol. However, the full set of genes that contribute to LXR-stimulated cholesterol efflux is unknown, and their identification is the objective of this study. Approach and Results— We systematically compared the global transcriptional response of macrophages to distinct classes of LXR ligands. This allowed us to identify both common and ligand-specific transcriptional responses in macrophages. Among these, we identified endonuclease–exonuclease–phosphatase family domain containing 1 (EEPD1/KIAA1706) as a direct transcriptional target of LXRs in human and murine macrophages. EEPD1 specifically localizes to the plasma membrane owing to the presence of a myristoylation site in its N terminus. Accordingly, the first 10 amino acids of EEPD1 are sufficient to confer plasma membrane localization in the context of a chimeric protein with GFP. Functionally, we report that silencing expression of EEPD1 blunts maximal LXR-stimulated Apo AI-dependent efflux and demonstrate that this is the result of reduced abundance of ABCA1 protein in human and murine macrophages. Conclusions— In this study, we identify EEPD1 as a novel LXR-regulated gene in macrophages and propose that it promotes cellular cholesterol efflux by controlling cellular levels and activity of ABCA1.
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Affiliation(s)
- Jessica Kristine Nelson
- From the Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, The Netherlands (J.K.N., D.S.K., S.S., E.C.L.C., M.M., A.S., N.Z.); and Université Clermont Auvergne, CNRS, Inserm, GReD, Clermont-Ferrand, France (J.-M.A.L., S.B.)
| | - Duco Steven Koenis
- From the Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, The Netherlands (J.K.N., D.S.K., S.S., E.C.L.C., M.M., A.S., N.Z.); and Université Clermont Auvergne, CNRS, Inserm, GReD, Clermont-Ferrand, France (J.-M.A.L., S.B.)
| | - Saskia Scheij
- From the Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, The Netherlands (J.K.N., D.S.K., S.S., E.C.L.C., M.M., A.S., N.Z.); and Université Clermont Auvergne, CNRS, Inserm, GReD, Clermont-Ferrand, France (J.-M.A.L., S.B.)
| | - Emma Clare Laura Cook
- From the Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, The Netherlands (J.K.N., D.S.K., S.S., E.C.L.C., M.M., A.S., N.Z.); and Université Clermont Auvergne, CNRS, Inserm, GReD, Clermont-Ferrand, France (J.-M.A.L., S.B.)
| | - Martina Moeton
- From the Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, The Netherlands (J.K.N., D.S.K., S.S., E.C.L.C., M.M., A.S., N.Z.); and Université Clermont Auvergne, CNRS, Inserm, GReD, Clermont-Ferrand, France (J.-M.A.L., S.B.)
| | - Ana Santos
- From the Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, The Netherlands (J.K.N., D.S.K., S.S., E.C.L.C., M.M., A.S., N.Z.); and Université Clermont Auvergne, CNRS, Inserm, GReD, Clermont-Ferrand, France (J.-M.A.L., S.B.)
| | - Jean-Marc Adolphe Lobaccaro
- From the Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, The Netherlands (J.K.N., D.S.K., S.S., E.C.L.C., M.M., A.S., N.Z.); and Université Clermont Auvergne, CNRS, Inserm, GReD, Clermont-Ferrand, France (J.-M.A.L., S.B.)
| | - Silvere Baron
- From the Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, The Netherlands (J.K.N., D.S.K., S.S., E.C.L.C., M.M., A.S., N.Z.); and Université Clermont Auvergne, CNRS, Inserm, GReD, Clermont-Ferrand, France (J.-M.A.L., S.B.)
| | - Noam Zelcer
- From the Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, The Netherlands (J.K.N., D.S.K., S.S., E.C.L.C., M.M., A.S., N.Z.); and Université Clermont Auvergne, CNRS, Inserm, GReD, Clermont-Ferrand, France (J.-M.A.L., S.B.).
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