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Epigenetic Regulation of Antibody Responses by the Histone H2A Deubiquitinase MYSM1.

Jiang XX, Chou Y, Jones L, Wang T, Sanchez S, Huang XF, Zhang L, Wang C, Chen SY - Sci Rep (2015)

Bottom Line: In this study, we found that mice deficient in the histone H2A deubiquitinase MYSM1, despite their severe defect in B cell development, exhibit an enhanced antibody response against both T cell-dependent and independent antigens.Mechanistic studies demonstrated that MYSM1 is a transcriptional activator of Pax5, the repressors of plasma cell differentiation, by facilitating key transcriptional factor recruitment and coordinating histone modifications at the Pax5 loci.Importantly, this study further provides a new target and strategy to modulate antibody production and responses with profound therapeutic implications.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Microbiology and Immunology, Norris Comprehensive Cancer Center Keck School of Medicine, University of Southern California, Los Angeles, California, 90033, USA.

ABSTRACT
B cell-mediated antibody response plays critical roles in protective immunity, as well as in the pathogenesis of allergic and autoimmune diseases. Epigenetic histone and DNA modifications regulate gene transcription and immunity; however, so far, little is known about the role of epigenetic regulation in antibody responses. In this study, we found that mice deficient in the histone H2A deubiquitinase MYSM1, despite their severe defect in B cell development, exhibit an enhanced antibody response against both T cell-dependent and independent antigens. We revealed that MYSM1 intrinsically represses plasma cell differentiation and antibody production. Mechanistic studies demonstrated that MYSM1 is a transcriptional activator of Pax5, the repressors of plasma cell differentiation, by facilitating key transcriptional factor recruitment and coordinating histone modifications at the Pax5 loci. Hence, this study uncovers a critical role for MYSM1 in epigenetically repressing plasma cell differentiation and antibody production, in addition to its opposing, active role in B cell development. Importantly, this study further provides a new target and strategy to modulate antibody production and responses with profound therapeutic implications.

No MeSH data available.


Related in: MedlinePlus

Reduced expression of Pax5 and Bach2 and increased expression of Blimp1 and Xbp1 in Mysm1−/− B cells.(a) qRT-PCR analysis of mRNA levels of representative genes in sorted WT and Mysm1−/− cells. Naive splenic B220+ cells (nB) from WT and Mysm1−/− mice were stimulated with LPS (20 μg/ml) in vitro and, 5 days later, LPS-activated B cells (aB, B220+CD138−) and plasma cells (PC, CD138+ B220+/−) were sorted by FACS. Relative mRNA levels were normalized by Hprt mRNA expression and calculated relative to the mRNA expression seen in the WT cells, set as 1. Data are representative of three independent experiments. **P < 0.01, *P < 0.05, WT vs. Mysm1−/−. (b) Forced expression of Pax5 reversed the enhanced plasma cell differentiation from Mysm1−/− B cells in vitro. Splenic B220+ cells from Mysm1−/− mice were transduced with a recombinant retroviral vector that expresses mouse Pax5, or control vector (RV-CONT). The transduced cells were stimulated with LPS (20 μg/ml), and, 2 and 4 days later, flow cytometric analysis was performed with indicated antibodies. (c) Enhanced expression of endogenous Pax5 by forced expression of MYSM1. Mysm1−/− B cells were transduced with LV-MYSM1 or control vector, and 24 hr later mRNA were isolated for qRT-PCR. Relative mRNA levels were normalized by Hprt mRNA expression and calculated relative to the mRNA expression seen in the cells transduced with control vector (LV-CONT), set as 1. Data are representative of two independent experiments. **P < 0.01, LV-CONT vs. LV-MYSM1. (d) Quantitative RT-PCR of representative genes in transduced Mysm1−/− B cells. Splenic Mysm1−/− B220+ cells were transduced with indicated recombinant retroviral vectors RV-Pax5 and stimulated with LPS (20 μg/ml). After 4 d stimulation, cells were collected for qRT-PCR. Relative mRNA levels were normalized by Hprt mRNA expression and calculated relative to the mRNA expression seen in the cells transduced with control vector (RV-CONT), set as 1. Data are representative of two independent experiments. **P < 0.01, RV-CONT vs. RV-Pax5. (e) MYSM1 mRNA levels in indicated sorted WT naïve B cells (nB), LPS-activated B cells (aB), and plasma cells (PC) from one of three independent experiments. **P < 0.01, nB vs. PC *P < 0.05, nB vs. aB.
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f5: Reduced expression of Pax5 and Bach2 and increased expression of Blimp1 and Xbp1 in Mysm1−/− B cells.(a) qRT-PCR analysis of mRNA levels of representative genes in sorted WT and Mysm1−/− cells. Naive splenic B220+ cells (nB) from WT and Mysm1−/− mice were stimulated with LPS (20 μg/ml) in vitro and, 5 days later, LPS-activated B cells (aB, B220+CD138−) and plasma cells (PC, CD138+ B220+/−) were sorted by FACS. Relative mRNA levels were normalized by Hprt mRNA expression and calculated relative to the mRNA expression seen in the WT cells, set as 1. Data are representative of three independent experiments. **P < 0.01, *P < 0.05, WT vs. Mysm1−/−. (b) Forced expression of Pax5 reversed the enhanced plasma cell differentiation from Mysm1−/− B cells in vitro. Splenic B220+ cells from Mysm1−/− mice were transduced with a recombinant retroviral vector that expresses mouse Pax5, or control vector (RV-CONT). The transduced cells were stimulated with LPS (20 μg/ml), and, 2 and 4 days later, flow cytometric analysis was performed with indicated antibodies. (c) Enhanced expression of endogenous Pax5 by forced expression of MYSM1. Mysm1−/− B cells were transduced with LV-MYSM1 or control vector, and 24 hr later mRNA were isolated for qRT-PCR. Relative mRNA levels were normalized by Hprt mRNA expression and calculated relative to the mRNA expression seen in the cells transduced with control vector (LV-CONT), set as 1. Data are representative of two independent experiments. **P < 0.01, LV-CONT vs. LV-MYSM1. (d) Quantitative RT-PCR of representative genes in transduced Mysm1−/− B cells. Splenic Mysm1−/− B220+ cells were transduced with indicated recombinant retroviral vectors RV-Pax5 and stimulated with LPS (20 μg/ml). After 4 d stimulation, cells were collected for qRT-PCR. Relative mRNA levels were normalized by Hprt mRNA expression and calculated relative to the mRNA expression seen in the cells transduced with control vector (RV-CONT), set as 1. Data are representative of two independent experiments. **P < 0.01, RV-CONT vs. RV-Pax5. (e) MYSM1 mRNA levels in indicated sorted WT naïve B cells (nB), LPS-activated B cells (aB), and plasma cells (PC) from one of three independent experiments. **P < 0.01, nB vs. PC *P < 0.05, nB vs. aB.

Mentions: To investigate the mechanism by which MYSM1 represses plasma cell generation and Ig production, we first examined the expression of a set of transcriptional factors that are critical for plasma cell generation and Ig production272829 by qRT-PCR assays. Naïve B cells, activated B cells and plasma cells were FACS sorted. Figure 5a shows that mRNA levels of Pax5 and Bach2 were significantly reduced, while Blimp1 and Xbp1 mRNA levels were significantly elevated in naïve and activated Mysm1−/− B cells. In agreement, Blimp1 and Xbp1 mRNA levels were drastically elevated and Pax5 and Bach2 mRNA levels were significantly reduced in CD138+ Mysm1−/− plasma cells derived from naïve B cells after LPS stimulation. We noticed that there was little difference in the expression of Bcl6, a transcriptional repressor of Blimp1 and Xbp1, in Mysm1−/− B cells and plasma cells compared to that in WT cells (data not shown). To confirm this observation, we sorted NP+B220+CD138− B cells and NP+CD138+B220− plasma cells from Mysm1−/− and WT mice immunized with NP-KLH for qRT-PCR assays and also observed a significant reduction in Pax5 and Bach2 expression and an increase in Blimp1 and Xbp1 mRNA in the Mysm1−/− B cells and plasma cells (data not shown).


Epigenetic Regulation of Antibody Responses by the Histone H2A Deubiquitinase MYSM1.

Jiang XX, Chou Y, Jones L, Wang T, Sanchez S, Huang XF, Zhang L, Wang C, Chen SY - Sci Rep (2015)

Reduced expression of Pax5 and Bach2 and increased expression of Blimp1 and Xbp1 in Mysm1−/− B cells.(a) qRT-PCR analysis of mRNA levels of representative genes in sorted WT and Mysm1−/− cells. Naive splenic B220+ cells (nB) from WT and Mysm1−/− mice were stimulated with LPS (20 μg/ml) in vitro and, 5 days later, LPS-activated B cells (aB, B220+CD138−) and plasma cells (PC, CD138+ B220+/−) were sorted by FACS. Relative mRNA levels were normalized by Hprt mRNA expression and calculated relative to the mRNA expression seen in the WT cells, set as 1. Data are representative of three independent experiments. **P < 0.01, *P < 0.05, WT vs. Mysm1−/−. (b) Forced expression of Pax5 reversed the enhanced plasma cell differentiation from Mysm1−/− B cells in vitro. Splenic B220+ cells from Mysm1−/− mice were transduced with a recombinant retroviral vector that expresses mouse Pax5, or control vector (RV-CONT). The transduced cells were stimulated with LPS (20 μg/ml), and, 2 and 4 days later, flow cytometric analysis was performed with indicated antibodies. (c) Enhanced expression of endogenous Pax5 by forced expression of MYSM1. Mysm1−/− B cells were transduced with LV-MYSM1 or control vector, and 24 hr later mRNA were isolated for qRT-PCR. Relative mRNA levels were normalized by Hprt mRNA expression and calculated relative to the mRNA expression seen in the cells transduced with control vector (LV-CONT), set as 1. Data are representative of two independent experiments. **P < 0.01, LV-CONT vs. LV-MYSM1. (d) Quantitative RT-PCR of representative genes in transduced Mysm1−/− B cells. Splenic Mysm1−/− B220+ cells were transduced with indicated recombinant retroviral vectors RV-Pax5 and stimulated with LPS (20 μg/ml). After 4 d stimulation, cells were collected for qRT-PCR. Relative mRNA levels were normalized by Hprt mRNA expression and calculated relative to the mRNA expression seen in the cells transduced with control vector (RV-CONT), set as 1. Data are representative of two independent experiments. **P < 0.01, RV-CONT vs. RV-Pax5. (e) MYSM1 mRNA levels in indicated sorted WT naïve B cells (nB), LPS-activated B cells (aB), and plasma cells (PC) from one of three independent experiments. **P < 0.01, nB vs. PC *P < 0.05, nB vs. aB.
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f5: Reduced expression of Pax5 and Bach2 and increased expression of Blimp1 and Xbp1 in Mysm1−/− B cells.(a) qRT-PCR analysis of mRNA levels of representative genes in sorted WT and Mysm1−/− cells. Naive splenic B220+ cells (nB) from WT and Mysm1−/− mice were stimulated with LPS (20 μg/ml) in vitro and, 5 days later, LPS-activated B cells (aB, B220+CD138−) and plasma cells (PC, CD138+ B220+/−) were sorted by FACS. Relative mRNA levels were normalized by Hprt mRNA expression and calculated relative to the mRNA expression seen in the WT cells, set as 1. Data are representative of three independent experiments. **P < 0.01, *P < 0.05, WT vs. Mysm1−/−. (b) Forced expression of Pax5 reversed the enhanced plasma cell differentiation from Mysm1−/− B cells in vitro. Splenic B220+ cells from Mysm1−/− mice were transduced with a recombinant retroviral vector that expresses mouse Pax5, or control vector (RV-CONT). The transduced cells were stimulated with LPS (20 μg/ml), and, 2 and 4 days later, flow cytometric analysis was performed with indicated antibodies. (c) Enhanced expression of endogenous Pax5 by forced expression of MYSM1. Mysm1−/− B cells were transduced with LV-MYSM1 or control vector, and 24 hr later mRNA were isolated for qRT-PCR. Relative mRNA levels were normalized by Hprt mRNA expression and calculated relative to the mRNA expression seen in the cells transduced with control vector (LV-CONT), set as 1. Data are representative of two independent experiments. **P < 0.01, LV-CONT vs. LV-MYSM1. (d) Quantitative RT-PCR of representative genes in transduced Mysm1−/− B cells. Splenic Mysm1−/− B220+ cells were transduced with indicated recombinant retroviral vectors RV-Pax5 and stimulated with LPS (20 μg/ml). After 4 d stimulation, cells were collected for qRT-PCR. Relative mRNA levels were normalized by Hprt mRNA expression and calculated relative to the mRNA expression seen in the cells transduced with control vector (RV-CONT), set as 1. Data are representative of two independent experiments. **P < 0.01, RV-CONT vs. RV-Pax5. (e) MYSM1 mRNA levels in indicated sorted WT naïve B cells (nB), LPS-activated B cells (aB), and plasma cells (PC) from one of three independent experiments. **P < 0.01, nB vs. PC *P < 0.05, nB vs. aB.
Mentions: To investigate the mechanism by which MYSM1 represses plasma cell generation and Ig production, we first examined the expression of a set of transcriptional factors that are critical for plasma cell generation and Ig production272829 by qRT-PCR assays. Naïve B cells, activated B cells and plasma cells were FACS sorted. Figure 5a shows that mRNA levels of Pax5 and Bach2 were significantly reduced, while Blimp1 and Xbp1 mRNA levels were significantly elevated in naïve and activated Mysm1−/− B cells. In agreement, Blimp1 and Xbp1 mRNA levels were drastically elevated and Pax5 and Bach2 mRNA levels were significantly reduced in CD138+ Mysm1−/− plasma cells derived from naïve B cells after LPS stimulation. We noticed that there was little difference in the expression of Bcl6, a transcriptional repressor of Blimp1 and Xbp1, in Mysm1−/− B cells and plasma cells compared to that in WT cells (data not shown). To confirm this observation, we sorted NP+B220+CD138− B cells and NP+CD138+B220− plasma cells from Mysm1−/− and WT mice immunized with NP-KLH for qRT-PCR assays and also observed a significant reduction in Pax5 and Bach2 expression and an increase in Blimp1 and Xbp1 mRNA in the Mysm1−/− B cells and plasma cells (data not shown).

Bottom Line: In this study, we found that mice deficient in the histone H2A deubiquitinase MYSM1, despite their severe defect in B cell development, exhibit an enhanced antibody response against both T cell-dependent and independent antigens.Mechanistic studies demonstrated that MYSM1 is a transcriptional activator of Pax5, the repressors of plasma cell differentiation, by facilitating key transcriptional factor recruitment and coordinating histone modifications at the Pax5 loci.Importantly, this study further provides a new target and strategy to modulate antibody production and responses with profound therapeutic implications.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Microbiology and Immunology, Norris Comprehensive Cancer Center Keck School of Medicine, University of Southern California, Los Angeles, California, 90033, USA.

ABSTRACT
B cell-mediated antibody response plays critical roles in protective immunity, as well as in the pathogenesis of allergic and autoimmune diseases. Epigenetic histone and DNA modifications regulate gene transcription and immunity; however, so far, little is known about the role of epigenetic regulation in antibody responses. In this study, we found that mice deficient in the histone H2A deubiquitinase MYSM1, despite their severe defect in B cell development, exhibit an enhanced antibody response against both T cell-dependent and independent antigens. We revealed that MYSM1 intrinsically represses plasma cell differentiation and antibody production. Mechanistic studies demonstrated that MYSM1 is a transcriptional activator of Pax5, the repressors of plasma cell differentiation, by facilitating key transcriptional factor recruitment and coordinating histone modifications at the Pax5 loci. Hence, this study uncovers a critical role for MYSM1 in epigenetically repressing plasma cell differentiation and antibody production, in addition to its opposing, active role in B cell development. Importantly, this study further provides a new target and strategy to modulate antibody production and responses with profound therapeutic implications.

No MeSH data available.


Related in: MedlinePlus