1
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Jin T, Wang Z, Fan F, Wei W, Zhou C, Zhang Z, Gao Y, Li W, Zhu L, Hao J. HDAC1 Promotes Mitochondrial Pathway Apoptosis and Inhibits the Endoplasmic Reticulum Stress Response in High Glucose-Treated Schwann Cells via Decreased U4 Spliceosomal RNA. Neurochem Res 2024:10.1007/s11064-024-04200-1. [PMID: 38916813 DOI: 10.1007/s11064-024-04200-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 06/18/2024] [Accepted: 06/19/2024] [Indexed: 06/26/2024]
Abstract
Dysfunction of Schwann cells, including cell apoptosis, autophagy inhibition, dedifferentiation, and pyroptosis, is a pivotal pathogenic factor in induced diabetic peripheral neuropathy (DPN). Histone deacetylases (HDACs) are an important family of proteins that epigenetically regulate gene transcription by affecting chromatin dynamics. Here, we explored the effect of HDAC1 on high glucose-cultured Schwann cells. HDAC1 expression was increased in diabetic mice and high glucose-cultured RSC96 cells, accompanied by cell apoptosis. High glucose also increased the mitochondrial pathway apoptosis-related Bax/Bcl-2 and cleaved caspase-9/caspase-9 ratios and decreased endoplasmic reticulum response-related GRP78, CHOP, and ATF4 expression in RSC96 cells (P < 0.05). Furthermore, overexpression of HDAC1 increased the ratios of Bax/Bcl-2, cleaved caspase-9/caspase-9, and cleaved caspase-3 and reduced the levels of GRP78, CHOP, and ATF4 in RSC96 cells (P < 0.05). In contrast, knockdown of HDAC1 inhibited high glucose-promoted mitochondrial pathway apoptosis and suppressed the endoplasmic reticulum response. Moreover, RNA sequencing revealed that U4 spliceosomal RNA was significantly reduced in HDAC1-overexpressing RSC96 cells. Silencing of U4 spliceosomal RNA led to an increase in Bax/Bcl-2 and cleaved caspase-9 and a decrease in CHOP and ATF4. Conversely, overexpression of U4 spliceosomal RNA blocked HDAC1-promoted mitochondrial pathway apoptosis and inhibited the endoplasmic reticulum response. In addition, alternative splicing analysis of HDAC1-overexpressing RSC96 cells showed that significantly differential intron retention (IR) of Rpl21, Cdc34, and Mtmr11 might be dominant downstream targets that mediate U4 deficiency-induced Schwann cell dysfunction. Taken together, these findings indicate that HDAC1 promotes mitochondrial pathway-mediated apoptosis and inhibits the endoplasmic reticulum stress response in high glucose-cultured Schwann cells by decreasing the U4 spliceosomal RNA/IR of Rpl21, Cdc34, and Mtmr11.
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Affiliation(s)
- Tingting Jin
- Department of Pathology, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, Hebei, 050017, China
- Center of Metabolic Diseases and Cancer Research, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Ziming Wang
- Experimental Center of Clinical College, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Fan Fan
- Department of Investigation, Hebei Vocational College of Public Security Police, Shijiazhuang, Hebei, China
| | - Wandi Wei
- Department of Pathology, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, Hebei, 050017, China
- Center of Metabolic Diseases and Cancer Research, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Chenming Zhou
- Department of Electron Microscopy, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Ziyu Zhang
- Department of Pathology, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, Hebei, 050017, China
- Center of Metabolic Diseases and Cancer Research, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Yue Gao
- Department of Pathology, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, Hebei, 050017, China
- Center of Metabolic Diseases and Cancer Research, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Wenhui Li
- Department of Pathology, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, Hebei, 050017, China
- Center of Metabolic Diseases and Cancer Research, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Lin Zhu
- Department of Electromyogram, the Third Hospital of Hebei Medical University, 139 Ziqiang Road, Shijiazhuang, Hebei, 050051, China.
| | - Jun Hao
- Department of Pathology, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, Hebei, 050017, China.
- Center of Metabolic Diseases and Cancer Research, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang, Hebei, China.
- Hebei Key Laboratory of Forensic Medicine, Shijiazhuang, Hebei, China.
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2
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Lee FFY, Harris C, Alper S. RNA Binding Proteins that Mediate LPS-induced Alternative Splicing of the MyD88 Innate Immune Regulator. J Mol Biol 2024; 436:168497. [PMID: 38369277 PMCID: PMC11001520 DOI: 10.1016/j.jmb.2024.168497] [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: 12/10/2023] [Revised: 02/08/2024] [Accepted: 02/14/2024] [Indexed: 02/20/2024]
Abstract
Inflammation driven by Toll-like receptor (TLR) signaling pathways is required to combat infection. However, inflammation can damage host tissues; thus it is essential that TLR signaling ultimately is terminated to prevent chronic inflammatory disorders. One mechanism that terminates persistent TLR signaling is alternative splicing of the MyD88 signaling adaptor, which functions in multiple TLR signaling pathways. While the canonical long isoform of MyD88 (MyD88-L) mediates TLR signaling and promotes inflammation, an alternatively-spliced shorter isoform of MyD88 (MyD88-S) produces a dominant negative inhibitor of TLR signaling. MyD88-S production is induced by inflammatory agonists including lipopolysaccharide (LPS), and thus MyD88-S induction is thought to act as a negative feedback loop that prevents chronic inflammation. Despite the potential role that MyD88-S production plays in inflammatory disorders, the mechanisms controlling MyD88 alternative splicing remain unclear. Here, we identify two RNA binding proteins, SRSF1 and HNRNPU, that regulate LPS-induced alternative splicing of MyD88.
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Affiliation(s)
- Frank Fang Yao Lee
- Department of Immunology and Genomic Medicine, National Jewish Health, Denver, CO 80206, USA; Center for Genes, Environment and Health, National Jewish Health, Denver, CO 80206, USA; Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz, CO 80045, USA
| | - Chelsea Harris
- Department of Immunology and Genomic Medicine, National Jewish Health, Denver, CO 80206, USA; Center for Genes, Environment and Health, National Jewish Health, Denver, CO 80206, USA; Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz, CO 80045, USA
| | - Scott Alper
- Department of Immunology and Genomic Medicine, National Jewish Health, Denver, CO 80206, USA; Center for Genes, Environment and Health, National Jewish Health, Denver, CO 80206, USA; Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz, CO 80045, USA.
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3
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The cellular biology of plasma cells: Unmet challenges and opportunities. Immunol Lett 2023; 254:6-12. [PMID: 36646289 DOI: 10.1016/j.imlet.2023.01.005] [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: 11/06/2022] [Revised: 12/27/2022] [Accepted: 01/09/2023] [Indexed: 01/15/2023]
Abstract
Plasma cells and the antibodies they secrete are paramount for protection against infection but can also be implicated in diseases including autoantibody-mediated disease and multiple myeloma. Plasma cell terminal differentiation relies on a transcriptional switch and on important morphological changes. The cellular and molecular mechanisms underlying these processes are partly understood and how plasma cells manage to survive for long periods of time while secreting large quantities of antibodies remains unclear. In this review we aim to put in perspective what is known about plasma cell cellular biology to highlight the challenges faced by this field of research but also to illustrate how new opportunities may arise from the study of the fundamental mechanisms sustaining plasma cell survival and function.
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4
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Lee FFY, Alper S. Alternative pre-mRNA splicing as a mechanism for terminating Toll-like Receptor signaling. Front Immunol 2022; 13:1023567. [PMID: 36531997 PMCID: PMC9755862 DOI: 10.3389/fimmu.2022.1023567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 11/11/2022] [Indexed: 12/03/2022] Open
Abstract
While inflammation induced by Toll-like receptor (TLR) signaling is required to combat infection, persistent inflammation can damage host tissues and contribute to a myriad of acute and chronic inflammatory disorders. Thus, it is essential not only that TLR signaling be activated in the presence of pathogens but that TLR signaling is ultimately terminated. One mechanism that limits persistent TLR signaling is alternative pre-mRNA splicing. In addition to encoding the canonical mRNAs that produce proteins that promote inflammation, many genes in the TLR signaling pathway also encode alternative mRNAs that produce proteins that are dominant negative inhibitors of signaling. Many of these negative regulators are induced by immune challenge, so production of these alternative isoforms represents a negative feedback loop that limits persistent inflammation. While these alternative splicing events have been investigated on a gene by gene basis, there has been limited systemic analysis of this mechanism that terminates TLR signaling. Here we review what is known about the production of negatively acting alternative isoforms in the TLR signaling pathway including how these inhibitors function, how they are produced, and what role they may play in inflammatory disease.
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Affiliation(s)
- Frank Fang Yao Lee
- Department of Immunology and Genomic Medicine and Center for Genes, Environment, and Health, National Jewish Health, Denver, CO, United States,Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz, CO, United States
| | - Scott Alper
- Department of Immunology and Genomic Medicine and Center for Genes, Environment, and Health, National Jewish Health, Denver, CO, United States,Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz, CO, United States,*Correspondence: Scott Alper,
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5
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Fuller EP, O'Neill RJ, Weiner MP. Derivation of splice junction-specific antibodies using a unique hapten targeting strategy and directed evolution. N Biotechnol 2022; 71:1-10. [PMID: 35750288 DOI: 10.1016/j.nbt.2022.06.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 06/05/2022] [Accepted: 06/19/2022] [Indexed: 10/31/2022]
Abstract
Alternative splicing of RNA occurs frequently in eukaryotic cells and can result in multiple protein isoforms that are nearly identical in amino acid sequence, but have unique biological roles. Moreover, the relative abundance of these unique isoforms can be correlative with diseased states and potentially used as biomarkers or therapeutic targets. However, due to high sequence similarities among isoforms, current proteomic methods are incapable of differentiating native protein isoforms derived from most alternative splicing events. Herein, a strategy employing a nonsynonymous, non-native amino acid (nnAA) pseudo-hapten (i.e. an amino acid or amino acid derivative that is different from the native amino acid at a particular position) as a targeting epitope in splice junction-spanning peptides was successful in directed antibody derivation. After isolating nnAA-specific antibodies, directed evolution reduced the antibody's binding dependence on the nnAA pseudo-hapten and improved binding to the native splice junction epitope. The resulting antibodies demonstrated codependent binding affinity to each exon of the splice junction and thus are splice junction- and isoform-specific. Furthermore, epitope scanning demonstrated that positioning of the nnAA pseudo-hapten within a peptide antigen can be exploited to predetermine the isolated antibody's specificity at, or near, amino acid resolution. Thus, this nnAA targeting strategy has the potential to robustly derive splice junction- and site-specific antibodies that can be used in a wide variety of research endeavors to unambiguously differentiate native protein isoforms.
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Affiliation(s)
- Emily P Fuller
- Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269, USA; Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA; Abcam, 688 East Main Street, Branford, CT 06405, USA
| | - Rachel J O'Neill
- Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269, USA; Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA.
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6
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Gao H, He C, Hua R, Guo Y, Wang B, Liang C, Gao L, Shang H, Xu JD. Endoplasmic Reticulum Stress of Gut Enterocyte and Intestinal Diseases. Front Mol Biosci 2022; 9:817392. [PMID: 35402506 PMCID: PMC8988245 DOI: 10.3389/fmolb.2022.817392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 01/19/2022] [Indexed: 12/21/2022] Open
Abstract
The endoplasmic reticulum, a vast reticular membranous network from the nuclear envelope to the plasma membrane responsible for the synthesis, maturation, and trafficking of a wide range of proteins, is considerably sensitive to changes in its luminal homeostasis. The loss of ER luminal homeostasis leads to abnormalities referred to as endoplasmic reticulum (ER) stress. Thus, the cell activates an adaptive response known as the unfolded protein response (UPR), a mechanism to stabilize ER homeostasis under severe environmental conditions. ER stress has recently been postulated as a disease research breakthrough due to its significant role in multiple vital cellular functions. This has caused numerous reports that ER stress-induced cell dysfunction has been implicated as an essential contributor to the occurrence and development of many diseases, resulting in them targeting the relief of ER stress. This review aims to outline the multiple molecular mechanisms of ER stress that can elucidate ER as an expansive, membrane-enclosed organelle playing a crucial role in numerous cellular functions with evident changes of several cells encountering ER stress. Alongside, we mainly focused on the therapeutic potential of ER stress inhibition in gastrointestinal diseases such as inflammatory bowel disease (IBD) and colorectal cancer. To conclude, we reviewed advanced research and highlighted future treatment strategies of ER stress-associated conditions.
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Affiliation(s)
- Han Gao
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Chengwei He
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Rongxuan Hua
- Department of Clinical Medicine, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Yuexin Guo
- Department of Oral Medicine, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Boya Wang
- Undergraduate Student of 2018 Eight Program of Clinical Medicine, Peking University Health Science Center, Beijing, China
| | - Chen Liang
- Department of Clinical Medicine, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Lei Gao
- Department of Biomedical Informatics, School of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Hongwei Shang
- Experimental Center for Morphological Research Platform, Capital Medical University, Beijing, China
| | - Jing-Dong Xu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
- *Correspondence: Jing-Dong Xu,
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7
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Characterizing the Interaction between the HTLV-1 Transactivator Tax-1 with Transcription Elongation Factor ELL2 and Its Impact on Viral Transactivation. Int J Mol Sci 2021; 22:ijms222413597. [PMID: 34948391 PMCID: PMC8705299 DOI: 10.3390/ijms222413597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 12/12/2021] [Accepted: 12/15/2021] [Indexed: 11/16/2022] Open
Abstract
The human T-cell leukemia virus type 1 (HTLV-1)-encoded transactivator and oncoprotein Tax-1 is essential for HTLV-1 replication. We recently found that Tax-1 interacts with transcription elongation factor for RNA polymerase II 2, ELL2, which enhances Tax-1-mediated transactivation of the HTLV-1 promotor. Here, we characterize the Tax-1:ELL2 interaction and its impact on viral transactivation by confocal imaging, co-immunoprecipitation, and luciferase assays. We found that Tax-1 and ELL2 not only co-precipitate, but also co-localize in dot-like structures in the nucleus. Tax-1:ELL2 complex formation occurred independently of Tax-1 point mutations, which are crucial for post translational modifications (PTMs) of Tax-1, suggesting that these PTMs are irrelevant for Tax-1:ELL2 interaction. In contrast, Tax-1 deletion mutants lacking either N-terminal (aa 1-37) or C-terminal regions (aa 150-353) of Tax-1 were impaired in interacting with ELL2. Contrary to Tax-1, the related, non-oncogenic Tax-2B from HTLV-2B did not interact with ELL2. Finally, we found that ELL2-R1 (aa 1-353), which carries an RNA polymerase II binding domain, and ELL2-R3 (aa 515-640) are sufficient to interact with Tax-1; however, only ELL2-truncations expressing R1 could enhance Tax-1-mediated transactivation of the HTLV-1 promoter. Together, this study identifies domains in Tax-1 and ELL2 being required for Tax-1:ELL2 complex formation and for viral transactivation.
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8
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Rogers GL, Cannon PM. Genome edited B cells: a new frontier in immune cell therapies. Mol Ther 2021; 29:3192-3204. [PMID: 34563675 PMCID: PMC8571172 DOI: 10.1016/j.ymthe.2021.09.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 09/13/2021] [Accepted: 09/20/2021] [Indexed: 10/20/2022] Open
Abstract
Cell therapies based on reprogrammed adaptive immune cells have great potential as "living drugs." As first demonstrated clinically for engineered chimeric antigen receptor (CAR) T cells, the ability of such cells to undergo clonal expansion in response to an antigen promotes both self-renewal and self-regulation in vivo. B cells also have the potential to be developed as immune cell therapies, but engineering their specificity and functionality is more challenging than for T cells. In part, this is due to the complexity of the immunoglobulin (Ig) locus, as well as the requirement for regulated expression of both cell surface B cell receptor and secreted antibody isoforms, in order to fully recapitulate the features of natural antibody production. Recent advances in genome editing are now allowing reprogramming of B cells by site-specific engineering of the Ig locus with preformed antibodies. In this review, we discuss the potential of engineered B cells as a cell therapy, the challenges involved in editing the Ig locus and the advances that are making this possible, and envision future directions for this emerging field of immune cell engineering.
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Affiliation(s)
- Geoffrey L Rogers
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Paula M Cannon
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
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9
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Blake D, Lynch KW. The three as: Alternative splicing, alternative polyadenylation and their impact on apoptosis in immune function. Immunol Rev 2021; 304:30-50. [PMID: 34368964 DOI: 10.1111/imr.13018] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/19/2021] [Accepted: 07/28/2021] [Indexed: 12/13/2022]
Abstract
The latest advances in next-generation sequencing studies and transcriptomic profiling over the past decade have highlighted a surprising frequency of genes regulated by RNA processing mechanisms in the immune system. In particular, two control steps in mRNA maturation, namely alternative splicing and alternative polyadenylation, are now recognized to occur in the vast majority of human genes. Both have the potential to alter the identity of the encoded protein, as well as control protein abundance or even protein localization or association with other factors. In this review, we will provide a summary of the general mechanisms by which alternative splicing (AS) and alternative polyadenylation (APA) occur, their regulation within cells of the immune system, and their impact on immunobiology. In particular, we will focus on how control of apoptosis by AS and APA is used to tune cell fate during an immune response.
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Affiliation(s)
- Davia Blake
- Immunology Graduate Group and the Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kristen W Lynch
- Immunology Graduate Group and the Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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10
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Lee FFY, Davidson K, Harris C, McClendon J, Janssen WJ, Alper S. NF-κB mediates lipopolysaccharide-induced alternative pre-mRNA splicing of MyD88 in mouse macrophages. J Biol Chem 2020; 295:6236-6248. [PMID: 32179652 DOI: 10.1074/jbc.ra119.011495] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 03/10/2020] [Indexed: 12/14/2022] Open
Abstract
Although a robust inflammatory response is needed to combat infection, this response must ultimately be terminated to prevent chronic inflammation. One mechanism that terminates inflammatory signaling is the production of alternative mRNA splice forms in the Toll-like receptor (TLR) signaling pathway. Whereas most genes in the TLR pathway encode positive mediators of inflammatory signaling, several, including that encoding the MyD88 signaling adaptor, also produce alternative spliced mRNA isoforms that encode dominant-negative inhibitors of the response. Production of these negatively acting alternatively spliced isoforms is induced by stimulation with the TLR4 agonist lipopolysaccharide (LPS); thus, this alternative pre-mRNA splicing represents a negative feedback loop that terminates TLR signaling and prevents chronic inflammation. In the current study, we investigated the mechanisms regulating the LPS-induced alternative pre-mRNA splicing of the MyD88 transcript in murine macrophages. We found that 1) the induction of the alternatively spliced MyD88 form is due to alternative pre-mRNA splicing and not caused by another RNA regulatory mechanism, 2) MyD88 splicing is regulated by both the MyD88- and TRIF-dependent arms of the TLR signaling pathway, 3) MyD88 splicing is regulated by the NF-κB transcription factor, and 4) NF-κB likely regulates MyD88 alternative pre-mRNA splicing per se rather than regulating splicing indirectly by altering MyD88 transcription. We conclude that alternative splicing of MyD88 may provide a sensitive mechanism that ensures robust termination of inflammation for tissue repair and restoration of normal tissue homeostasis once an infection is controlled.
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Affiliation(s)
- Frank Fang-Yao Lee
- Department of Biomedical Research, National Jewish Health, Denver, Colorado 80206; Center for Genes, Environment and Health, National Jewish Health, Denver, Colorado 80206; Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado 80045
| | - Kevin Davidson
- Pulmonary and Critical Care, WakeMed Hospital, Raleigh, North Carolina 27610
| | - Chelsea Harris
- Department of Biomedical Research, National Jewish Health, Denver, Colorado 80206; Center for Genes, Environment and Health, National Jewish Health, Denver, Colorado 80206; Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado 80045
| | - Jazalle McClendon
- Department of Medicine, National Jewish Health, Denver, Colorado 80206
| | - William J Janssen
- Department of Medicine, National Jewish Health, Denver, Colorado 80206; Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado 80045
| | - Scott Alper
- Department of Biomedical Research, National Jewish Health, Denver, Colorado 80206; Center for Genes, Environment and Health, National Jewish Health, Denver, Colorado 80206; Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado 80045.
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11
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Ghobrial A, Flick N, Daly R, Hoffman M, Milcarek C. ELL2 Influences Transcription Elongation, Splicing, Ig Secretion and Growth. JOURNAL OF MUCOSAL IMMUNOLOGY RESEARCH 2019; 3:112. [PMID: 31930204 PMCID: PMC6953911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
ELL2 was previously discovered as a member of the Super Elongation Complex. It is involved in driving the maturation of B cells to plasma cells through shifting patterns of RNA processing, favoring generation of the secretory form of heavy chain immunoglobulin (IgH) associated with plasma cells. ELL2 influences the expression and splicing patterns of more than 4,000 genes in antibody secreting cells. The ELL2 gene has been implicated in cancers such as multiple myeloma and salivary gland carcinoma. A member of the ELL family (ELL1) was recently proven to act as an E3 ubiquitin ligase to known proto-oncogene, c-Myc, through a highly conserved cysteine residue in the C-terminal CEYLH region. Comparison of sequence homology shows this region is conserved between the three members of the ELL family, leading us to hypothesize that the other two ELLs (2 and 3) could serve the same role. In this review, we summarize what is known about ELL2 with respect to its role in driving B cell to plasma cell differentiation as well as its potential role in tumor suppression.
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Affiliation(s)
| | | | | | | | - Christine Milcarek
- Corresponding author: Dr. Christine Milcarek, Department of Immunology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA, Tel: 02-3937-6828;
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12
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Carew NT, Nelson AM, Liang Z, Smith SM, Milcarek C. Linking Endoplasmic Reticular Stress and Alternative Splicing. Int J Mol Sci 2018; 19:ijms19123919. [PMID: 30544499 PMCID: PMC6321306 DOI: 10.3390/ijms19123919] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 12/04/2018] [Accepted: 12/05/2018] [Indexed: 12/16/2022] Open
Abstract
RNA splicing patterns in antibody-secreting cells are shaped by endoplasmic reticulum stress, ELL2 (eleven-nineteen lysine-rich leukemia gene 2) induction, and changes in the levels of snRNAs. Endoplasmic reticulum stress induces the unfolded protein response comprising a highly conserved set of genes crucial for cell survival; among these is Ire1, whose auto-phosphorylation drives it to acquire a regulated mRNA decay activity. The mRNA-modifying function of phosphorylated Ire1 non-canonically splices Xbp1 mRNA and yet degrades other cellular mRNAs with related motifs. Naïve splenic B cells will activate Ire1 phosphorylation early on after lipopolysaccharide (LPS) stimulation, within 18 h; large-scale changes in mRNA content and splicing patterns result. Inhibition of the mRNA-degradation function of Ire1 is correlated with further differences in the splicing patterns and a reduction in the mRNA factors for snRNA transcription. Some of the >4000 splicing changes seen at 18 h after LPS stimulation persist into the late stages of antibody secretion, up to 72 h. Meanwhile some early splicing changes are supplanted by new splicing changes introduced by the up-regulation of ELL2, a transcription elongation factor. ELL2 is necessary for immunoglobulin secretion and does this by changing mRNA processing patterns of immunoglobulin heavy chain and >5000 other genes.
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Affiliation(s)
- Nolan T Carew
- School of Medicine, Department of Immunology, University of Pittsburgh, E1059 Biomedical Science Tower, Pittsburgh, PA 15261, USA.
| | - Ashley M Nelson
- School of Medicine, Department of Immunology, University of Pittsburgh, E1059 Biomedical Science Tower, Pittsburgh, PA 15261, USA.
| | - Zhitao Liang
- School of Medicine, Department of Immunology, University of Pittsburgh, E1059 Biomedical Science Tower, Pittsburgh, PA 15261, USA.
| | - Sage M Smith
- School of Medicine, Department of Immunology, University of Pittsburgh, E1059 Biomedical Science Tower, Pittsburgh, PA 15261, USA.
| | - Christine Milcarek
- School of Medicine, Department of Immunology, University of Pittsburgh, E1059 Biomedical Science Tower, Pittsburgh, PA 15261, USA.
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