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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

MYSM1 intrinsically represses plasma cell differentiation.(a) Representative flow cytometric analysis of CD138+ plasma cells in the bone marrow (BM), spleen (SP), draining lymph node (dLN), and mesenteric lymph node (mLN) of naive WT and Mysm1−/− mice. Numbers are the percentage of events within the indicated gates. (b) Graphs show the percent of CD138+ plasma cells, total number of CD138+ cells, total number of B220+ cells, and CD138+ cells per million B cells in bone marrow (top) or spleen (bottom) of naïve WT and Mysm1−/− mice (n = 5–8 per group). **P < 0.01, WT vs. Mysm1−/−. (c) Flow cytometric analysis of indicated surface markers in the bone marrow, spleen, and lymph node of WT and Mysm1−/− mice 14 days after NP-KLH immunization. (d) Splenic B cells from WT and Mysm1−/− mice immunized with NL-KLH were cultured in 96-well plate. Spot numbers (top) and representative spots (bottom) in the indicated cultures from triplicate wells ± SEM are shown from one of two independent experiments. **P < 0.01, WT vs. Mysm1−/−. (e) Enhanced spontaneous differentiation of plasma cells from naïve splenic Mysm1−/− B cells in vitro. Splenic B220+ B cells from WT and Mysm1−/− mice were cultured with IL-4 (10 ng/ml) for 4 days. Representative flow cytometric analysis is shown (n = 5–8 per group). **P < 0.01, WT vs. Mysm1−/−. (f) Enhanced plasma cell differentiation of Mysm1−/− B cells after LPS stimulation in vitro. Splenic B220+ cells from WT and Mysm1−/− mice were cultured with LPS (20 μg/ml) and were collected at indicated days for flow cytometric analysis. (g,h) MYSM1 rescue assays. Splenic B220+ cells from Mysm1−/− mice were transduced with a recombinant lentiviral vector LV-MYSM1 or control vector LV-CONT. The transduced cells were subjected to flow cytometric analysis with indicated antibodies after LPS (20 μg/ml) stimulation in vitro (g). Quantitative RT-PCR analysis of MYSM1, Blimp1, and Xbp1 mRNA levels in Mysm1−/− splenic B220+ cells transduced with LV-CONT or LV-MYSM1 (h). Data were normalized to Hprt and are presented as relative to that of control LV-CONT sample, set as 1, from one of two independent experiments. **p < 0.01, LV-CONT vs. LV-MYSM1.
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f3: MYSM1 intrinsically represses plasma cell differentiation.(a) Representative flow cytometric analysis of CD138+ plasma cells in the bone marrow (BM), spleen (SP), draining lymph node (dLN), and mesenteric lymph node (mLN) of naive WT and Mysm1−/− mice. Numbers are the percentage of events within the indicated gates. (b) Graphs show the percent of CD138+ plasma cells, total number of CD138+ cells, total number of B220+ cells, and CD138+ cells per million B cells in bone marrow (top) or spleen (bottom) of naïve WT and Mysm1−/− mice (n = 5–8 per group). **P < 0.01, WT vs. Mysm1−/−. (c) Flow cytometric analysis of indicated surface markers in the bone marrow, spleen, and lymph node of WT and Mysm1−/− mice 14 days after NP-KLH immunization. (d) Splenic B cells from WT and Mysm1−/− mice immunized with NL-KLH were cultured in 96-well plate. Spot numbers (top) and representative spots (bottom) in the indicated cultures from triplicate wells ± SEM are shown from one of two independent experiments. **P < 0.01, WT vs. Mysm1−/−. (e) Enhanced spontaneous differentiation of plasma cells from naïve splenic Mysm1−/− B cells in vitro. Splenic B220+ B cells from WT and Mysm1−/− mice were cultured with IL-4 (10 ng/ml) for 4 days. Representative flow cytometric analysis is shown (n = 5–8 per group). **P < 0.01, WT vs. Mysm1−/−. (f) Enhanced plasma cell differentiation of Mysm1−/− B cells after LPS stimulation in vitro. Splenic B220+ cells from WT and Mysm1−/− mice were cultured with LPS (20 μg/ml) and were collected at indicated days for flow cytometric analysis. (g,h) MYSM1 rescue assays. Splenic B220+ cells from Mysm1−/− mice were transduced with a recombinant lentiviral vector LV-MYSM1 or control vector LV-CONT. The transduced cells were subjected to flow cytometric analysis with indicated antibodies after LPS (20 μg/ml) stimulation in vitro (g). Quantitative RT-PCR analysis of MYSM1, Blimp1, and Xbp1 mRNA levels in Mysm1−/− splenic B220+ cells transduced with LV-CONT or LV-MYSM1 (h). Data were normalized to Hprt and are presented as relative to that of control LV-CONT sample, set as 1, from one of two independent experiments. **p < 0.01, LV-CONT vs. LV-MYSM1.

Mentions: When examining frequencies of plasma cells, we observed higher frequencies of CD138+B220− plasma cells in the spleens of naïve Mysm1−/− mice, although the total plasma cell and B cell numbers were drastically lower (Fig. 3a,b). Consistently, we also observed higher frequencies of CD138+B220− plasma cells in the BM and lymph nodes (LN) of naïve Mysm1−/− mice. These data suggest an enhanced spontaneous differentiation of B cells into plasma cells in Mysm1−/− mice. To investigate the possible role of MYSM1 in plasma cell differentiation, we used flow cytometry to quantify plasma cells and antigen-specific NP+ B cells and plasma cells in Mysm1−/− mice after NP-KLH immunization. Drastic increases in both CD138+ plasma cells and antigen-specific NP+CD138+ plasma cells were observed in various tissues of immunized Mysm1−/− mice (Fig. 3c). Moreover, ELISPOT assays showed higher frequencies of NP-specific, class switched IgG-producing cells (Fig. 3d). Thus, these data indicate that MYSM1 plays a repressive role in plasma cell differentiation.


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)

MYSM1 intrinsically represses plasma cell differentiation.(a) Representative flow cytometric analysis of CD138+ plasma cells in the bone marrow (BM), spleen (SP), draining lymph node (dLN), and mesenteric lymph node (mLN) of naive WT and Mysm1−/− mice. Numbers are the percentage of events within the indicated gates. (b) Graphs show the percent of CD138+ plasma cells, total number of CD138+ cells, total number of B220+ cells, and CD138+ cells per million B cells in bone marrow (top) or spleen (bottom) of naïve WT and Mysm1−/− mice (n = 5–8 per group). **P < 0.01, WT vs. Mysm1−/−. (c) Flow cytometric analysis of indicated surface markers in the bone marrow, spleen, and lymph node of WT and Mysm1−/− mice 14 days after NP-KLH immunization. (d) Splenic B cells from WT and Mysm1−/− mice immunized with NL-KLH were cultured in 96-well plate. Spot numbers (top) and representative spots (bottom) in the indicated cultures from triplicate wells ± SEM are shown from one of two independent experiments. **P < 0.01, WT vs. Mysm1−/−. (e) Enhanced spontaneous differentiation of plasma cells from naïve splenic Mysm1−/− B cells in vitro. Splenic B220+ B cells from WT and Mysm1−/− mice were cultured with IL-4 (10 ng/ml) for 4 days. Representative flow cytometric analysis is shown (n = 5–8 per group). **P < 0.01, WT vs. Mysm1−/−. (f) Enhanced plasma cell differentiation of Mysm1−/− B cells after LPS stimulation in vitro. Splenic B220+ cells from WT and Mysm1−/− mice were cultured with LPS (20 μg/ml) and were collected at indicated days for flow cytometric analysis. (g,h) MYSM1 rescue assays. Splenic B220+ cells from Mysm1−/− mice were transduced with a recombinant lentiviral vector LV-MYSM1 or control vector LV-CONT. The transduced cells were subjected to flow cytometric analysis with indicated antibodies after LPS (20 μg/ml) stimulation in vitro (g). Quantitative RT-PCR analysis of MYSM1, Blimp1, and Xbp1 mRNA levels in Mysm1−/− splenic B220+ cells transduced with LV-CONT or LV-MYSM1 (h). Data were normalized to Hprt and are presented as relative to that of control LV-CONT sample, set as 1, from one of two independent experiments. **p < 0.01, LV-CONT vs. LV-MYSM1.
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f3: MYSM1 intrinsically represses plasma cell differentiation.(a) Representative flow cytometric analysis of CD138+ plasma cells in the bone marrow (BM), spleen (SP), draining lymph node (dLN), and mesenteric lymph node (mLN) of naive WT and Mysm1−/− mice. Numbers are the percentage of events within the indicated gates. (b) Graphs show the percent of CD138+ plasma cells, total number of CD138+ cells, total number of B220+ cells, and CD138+ cells per million B cells in bone marrow (top) or spleen (bottom) of naïve WT and Mysm1−/− mice (n = 5–8 per group). **P < 0.01, WT vs. Mysm1−/−. (c) Flow cytometric analysis of indicated surface markers in the bone marrow, spleen, and lymph node of WT and Mysm1−/− mice 14 days after NP-KLH immunization. (d) Splenic B cells from WT and Mysm1−/− mice immunized with NL-KLH were cultured in 96-well plate. Spot numbers (top) and representative spots (bottom) in the indicated cultures from triplicate wells ± SEM are shown from one of two independent experiments. **P < 0.01, WT vs. Mysm1−/−. (e) Enhanced spontaneous differentiation of plasma cells from naïve splenic Mysm1−/− B cells in vitro. Splenic B220+ B cells from WT and Mysm1−/− mice were cultured with IL-4 (10 ng/ml) for 4 days. Representative flow cytometric analysis is shown (n = 5–8 per group). **P < 0.01, WT vs. Mysm1−/−. (f) Enhanced plasma cell differentiation of Mysm1−/− B cells after LPS stimulation in vitro. Splenic B220+ cells from WT and Mysm1−/− mice were cultured with LPS (20 μg/ml) and were collected at indicated days for flow cytometric analysis. (g,h) MYSM1 rescue assays. Splenic B220+ cells from Mysm1−/− mice were transduced with a recombinant lentiviral vector LV-MYSM1 or control vector LV-CONT. The transduced cells were subjected to flow cytometric analysis with indicated antibodies after LPS (20 μg/ml) stimulation in vitro (g). Quantitative RT-PCR analysis of MYSM1, Blimp1, and Xbp1 mRNA levels in Mysm1−/− splenic B220+ cells transduced with LV-CONT or LV-MYSM1 (h). Data were normalized to Hprt and are presented as relative to that of control LV-CONT sample, set as 1, from one of two independent experiments. **p < 0.01, LV-CONT vs. LV-MYSM1.
Mentions: When examining frequencies of plasma cells, we observed higher frequencies of CD138+B220− plasma cells in the spleens of naïve Mysm1−/− mice, although the total plasma cell and B cell numbers were drastically lower (Fig. 3a,b). Consistently, we also observed higher frequencies of CD138+B220− plasma cells in the BM and lymph nodes (LN) of naïve Mysm1−/− mice. These data suggest an enhanced spontaneous differentiation of B cells into plasma cells in Mysm1−/− mice. To investigate the possible role of MYSM1 in plasma cell differentiation, we used flow cytometry to quantify plasma cells and antigen-specific NP+ B cells and plasma cells in Mysm1−/− mice after NP-KLH immunization. Drastic increases in both CD138+ plasma cells and antigen-specific NP+CD138+ plasma cells were observed in various tissues of immunized Mysm1−/− mice (Fig. 3c). Moreover, ELISPOT assays showed higher frequencies of NP-specific, class switched IgG-producing cells (Fig. 3d). Thus, these data indicate that MYSM1 plays a repressive role in plasma cell differentiation.

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