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Subramani PG, Fraszczak J, Helness A, Estall JL, Möröy T, Di Noia JM. Conserved role of hnRNPL in alternative splicing of epigenetic modifiers enables B cell activation. EMBO Rep 2024; 25:2662-2697. [PMID: 38744970 PMCID: PMC11169469 DOI: 10.1038/s44319-024-00152-3] [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: 10/05/2023] [Revised: 04/15/2024] [Accepted: 04/24/2024] [Indexed: 05/16/2024] Open
Abstract
The multifunctional RNA-binding protein hnRNPL is implicated in antibody class switching but its broader function in B cells is unknown. Here, we show that hnRNPL is essential for B cell activation, germinal center formation, and antibody responses. Upon activation, hnRNPL-deficient B cells show proliferation defects and increased apoptosis. Comparative analysis of RNA-seq data from activated B cells and another eight hnRNPL-depleted cell types reveals common effects on MYC and E2F transcriptional programs required for proliferation. Notably, while individual gene expression changes are cell type specific, several alternative splicing events affecting histone modifiers like KDM6A and SIRT1, are conserved across cell types. Moreover, hnRNPL-deficient B cells show global changes in H3K27me3 and H3K9ac. Epigenetic dysregulation after hnRNPL loss could underlie differential gene expression and upregulation of lncRNAs, and explain common and cell type-specific phenotypes, such as dysfunctional mitochondria and ROS overproduction in mouse B cells. Thus, hnRNPL is essential for the resting-to-activated B cell transition by regulating transcriptional programs and metabolism, at least in part through the alternative splicing of several histone modifiers.
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Affiliation(s)
- Poorani Ganesh Subramani
- Institut de Recherches Cliniques de Montréal, 110 avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada
- Department of Medicine, Division of Experimental Medicine, McGill University, 1001 Boulevard Decarie, Montreal, QC, H4A 3J1, Canada
| | - Jennifer Fraszczak
- Institut de Recherches Cliniques de Montréal, 110 avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada
| | - Anne Helness
- Institut de Recherches Cliniques de Montréal, 110 avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada
| | - Jennifer L Estall
- Institut de Recherches Cliniques de Montréal, 110 avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada
- Department of Medicine, Division of Experimental Medicine, McGill University, 1001 Boulevard Decarie, Montreal, QC, H4A 3J1, Canada
- Molecular Biology Programs, Université de Montréal, C.P. 6128, succ. Centre-ville, Montréal, QC, H3C 3J7, Canada
- Department of Medicine, Université de Montréal, C.P. 6128, succ. Centre-ville, Montréal, QC, H3C 3J7, Canada
| | - Tarik Möröy
- Institut de Recherches Cliniques de Montréal, 110 avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada
- Department of Medicine, Division of Experimental Medicine, McGill University, 1001 Boulevard Decarie, Montreal, QC, H4A 3J1, Canada
- Molecular Biology Programs, Université de Montréal, C.P. 6128, succ. Centre-ville, Montréal, QC, H3C 3J7, Canada
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, 2900 Boul Edouard-Montpetit, Montréal, QC, H3T 1J4, Canada
| | - Javier M Di Noia
- Institut de Recherches Cliniques de Montréal, 110 avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada.
- Department of Medicine, Division of Experimental Medicine, McGill University, 1001 Boulevard Decarie, Montreal, QC, H4A 3J1, Canada.
- Molecular Biology Programs, Université de Montréal, C.P. 6128, succ. Centre-ville, Montréal, QC, H3C 3J7, Canada.
- Department of Medicine, Université de Montréal, C.P. 6128, succ. Centre-ville, Montréal, QC, H3C 3J7, Canada.
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, 2900 Boul Edouard-Montpetit, Montréal, QC, H3T 1J4, Canada.
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Zhang Y, Zhang Y, Song J, Cheng X, Zhou C, Huang S, Zhao W, Zong Z, Yang L. Targeting the "tumor microenvironment": RNA-binding proteins in the spotlight in colorectal cancer therapy. Int Immunopharmacol 2024; 131:111876. [PMID: 38493688 DOI: 10.1016/j.intimp.2024.111876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/04/2024] [Accepted: 03/13/2024] [Indexed: 03/19/2024]
Abstract
Colorectal cancer (CRC) is the third most common cancer and has the second highest mortality rate among cancers. The development of CRC involves both genetic and epigenetic abnormalities, and recent research has focused on exploring the ex-transcriptome, particularly post-transcriptional modifications. RNA-binding proteins (RBPs) are emerging epigenetic regulators that play crucial roles in post-transcriptional events. Dysregulation of RBPs can result in aberrant expression of downstream target genes, thereby affecting the progression of colorectal tumors and the prognosis of patients. Recent studies have shown that RBPs can influence CRC pathogenesis and progression by regulating various components of the tumor microenvironment (TME). Although previous research on RBPs has primarily focused on their direct regulation of colorectal tumor development, their involvement in the remodeling of the TME has not been systematically reported. This review aims to highlight the significant role of RBPs in the intricate interactions within the CRC tumor microenvironment, including tumor immune microenvironment, inflammatory microenvironment, extracellular matrix, tumor vasculature, and CRC cancer stem cells. We also highlight several compounds under investigation for RBP-TME-based treatment of CRC, including small molecule inhibitors such as antisense oligonucleotides (ASOs), siRNAs, agonists, gene manipulation, and tumor vaccines. The insights gained from this review may lead to the development of RBP-based targeted novel therapeutic strategies aimed at modulating the TME, potentially inhibiting the progression and metastasis of CRC.
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Affiliation(s)
- Yiwei Zhang
- Department of Gastrointestinal Surgery, the Second Affiliated Hospital of Nanchang University, No. 1 MinDe Road, 330006 Nanchang, China; Department of Gastroenterology, The Second Affiliated Hospital of Nanchang University, No. 1 Mingde Rd., Nanchang 330006, Jiangxi, China; Queen Mary School, Nanchang University, 330006 Nanchang, China
| | - Yujun Zhang
- Department of Gastrointestinal Surgery, the Second Affiliated Hospital of Nanchang University, No. 1 MinDe Road, 330006 Nanchang, China; Department of Gastroenterology, The Second Affiliated Hospital of Nanchang University, No. 1 Mingde Rd., Nanchang 330006, Jiangxi, China
| | - Jingjing Song
- Department of Gastrointestinal Surgery, the Second Affiliated Hospital of Nanchang University, No. 1 MinDe Road, 330006 Nanchang, China; Department of Gastroenterology, The Second Affiliated Hospital of Nanchang University, No. 1 Mingde Rd., Nanchang 330006, Jiangxi, China; School of Ophthalmology and Optometry of Nanchang University, China
| | - Xifu Cheng
- School of Ophthalmology and Optometry of Nanchang University, China
| | - Chulin Zhou
- The Second Clinical Medical College, Nanchang University, Nanchang 330006, China
| | - Shuo Huang
- The Second Clinical Medical College, Nanchang University, Nanchang 330006, China
| | - Wentao Zhao
- The 3rd Clinical Department of China Medical University, 10159 Shenyang, China
| | - Zhen Zong
- Department of Gastrointestinal Surgery, the Second Affiliated Hospital of Nanchang University, No. 1 MinDe Road, 330006 Nanchang, China.
| | - Lingling Yang
- Department of Gastroenterology, The Second Affiliated Hospital of Nanchang University, No. 1 Mingde Rd., Nanchang 330006, Jiangxi, China.
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White TLA, Jin Y, Roberts SDA, Gable MJ, Morel PA. Phosphorylation of hnRNP A1-Serine 199 Is Not Required for T Cell Differentiation and Function. Immunohorizons 2024; 8:136-146. [PMID: 38334757 PMCID: PMC10916359 DOI: 10.4049/immunohorizons.2300074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 01/05/2024] [Indexed: 02/10/2024] Open
Abstract
hnRNP A1 is an important RNA-binding protein that influences many stages of RNA processing, including transcription, alternative splicing, mRNA nuclear export, and RNA stability. However, the role of hnRNP A1 in immune cells, specifically CD4+ T cells, remains unclear. We previously showed that Akt phosphorylation of hnRNP A1 was dependent on TCR signal strength and was associated with Treg differentiation. To explore the impact of hnRNP A1 phosphorylation by Akt on CD4+ T cell differentiation, our laboratory generated a mutant mouse model, hnRNP A1-S199A (A1-MUT) in which the major Akt phosphorylation site on hnRNP A1 was mutated to alanine using CRISPR Cas9 technology. Immune profiling of A1-MUT mice revealed changes in the numbers of Tregs in the mesenteric lymph node. We found no significant differences in naive CD4+ T cell differentiation into Th1, Th2, Th17, or T regulatory cells (Tregs) in vitro. In vivo, Treg differentiation assays using OTII-A1-Mut CD4+ T cells exposed to OVA food revealed migration and homing defects in the A1-MUT but no change in Treg induction. A1-MUT mice were immunized with NP- keyhole limpet hemocyanin, and normal germinal center development, normal numbers of NP-specific B cells, and no change in Tfh numbers were observed. In conclusion, Akt phosphorylation of hnRNP A1 S199 does not play a role in CD4+ T cell fate or function in the models tested. This hnRNP A1-S199A mouse model should be a valuable tool to study the role of Akt phosphorylation of hnRNP A1-S199 in different cell types or other mouse models of human disease.
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Affiliation(s)
- Tristan L. A. White
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Ye Jin
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Sean D. A. Roberts
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Matthew J. Gable
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Penelope A. Morel
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA
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