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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

Enhanced recall TD antibody responses in Mysm1−/− mice.(a,b) Flow cytometry analysis of splenocytes of WT and Mysm1−/− mice 14 days after intraperitoneal immunization with NP-KLH (100 μg) in alum. PI−CD4−CD8−Gr-1− cells were analyzed for NP+CD138+, NP+B220+, and NP+IgG1+ cells (a). Numbers indicate the percent in each. Absolute cell numbers of NP+B220+ B cells, NP+CD138+ plasma cells, and NP+IgG+ antibody-producing cells per million B220+ cells for each group (n = 5–8 per group) 14 days after primary intraperitoneal immunization with NP-KLH (100 μg) precipitated in alum from one of three independent experiments (b). **P < 0.01, WT vs. Mysm1−/−. (c) Flow cytometry analysis of splenocytes 14 days after intraperitoneal immunization with NP-KLH in alum. Isotype-switched B cells (IgM−IgD−Gr−1−CD138−B220+) were analyzed for NP+IgG1+ status with NP+IgG1+ cells being subdivided into GC (CD38−) and memory (CD38+) B cells. Numbers in plots and histograms represent percentage of cells within the gate. (d) Frozen spleen sections from WT and Mysm1−/− mice 14 days after immunization with NP-KLH, stained with antibodies to B220 to identify follicles (red) and GL7 for germinal centers (green). Original magnification is x10 (top) and x20 (bottom). (e) Frequencies of total (NP26) and high-affinity (NP4) NP-specific-secreting ASCs in spleen and bone marrow examined by ELISOPT assays. Data are the mean ± SEM of triplicate wells, with four to six mice in each group. **P < 0.01, WT vs. Mysm1−/−. (f) Mice were immunized with NP-KLH (100 μg in alum) and boosted with NP-KLH (50 μg in PBS) 42 days later. Serum was collected before boost immunization and 5 days after boost and analyzed by ELISA with NP26-BSA-coated plates for detecting NP-specific IgG1, IgG2a, IgG2b, and IgG3 antibodies. (g,h) Frequencies of total (NP26) and high-affinity (NP4) NP-specific-IgG1 secreting cells (ASCs) in spleen 42 days after primary immunization (g) and day 5 after boost (h). Data are the mean ± SEM of triplicate wells, with four to six mice in each group, and representative of two experiments. **p < 0.01, Mysm1−/−vs. WT.
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f2: Enhanced recall TD antibody responses in Mysm1−/− mice.(a,b) Flow cytometry analysis of splenocytes of WT and Mysm1−/− mice 14 days after intraperitoneal immunization with NP-KLH (100 μg) in alum. PI−CD4−CD8−Gr-1− cells were analyzed for NP+CD138+, NP+B220+, and NP+IgG1+ cells (a). Numbers indicate the percent in each. Absolute cell numbers of NP+B220+ B cells, NP+CD138+ plasma cells, and NP+IgG+ antibody-producing cells per million B220+ cells for each group (n = 5–8 per group) 14 days after primary intraperitoneal immunization with NP-KLH (100 μg) precipitated in alum from one of three independent experiments (b). **P < 0.01, WT vs. Mysm1−/−. (c) Flow cytometry analysis of splenocytes 14 days after intraperitoneal immunization with NP-KLH in alum. Isotype-switched B cells (IgM−IgD−Gr−1−CD138−B220+) were analyzed for NP+IgG1+ status with NP+IgG1+ cells being subdivided into GC (CD38−) and memory (CD38+) B cells. Numbers in plots and histograms represent percentage of cells within the gate. (d) Frozen spleen sections from WT and Mysm1−/− mice 14 days after immunization with NP-KLH, stained with antibodies to B220 to identify follicles (red) and GL7 for germinal centers (green). Original magnification is x10 (top) and x20 (bottom). (e) Frequencies of total (NP26) and high-affinity (NP4) NP-specific-secreting ASCs in spleen and bone marrow examined by ELISOPT assays. Data are the mean ± SEM of triplicate wells, with four to six mice in each group. **P < 0.01, WT vs. Mysm1−/−. (f) Mice were immunized with NP-KLH (100 μg in alum) and boosted with NP-KLH (50 μg in PBS) 42 days later. Serum was collected before boost immunization and 5 days after boost and analyzed by ELISA with NP26-BSA-coated plates for detecting NP-specific IgG1, IgG2a, IgG2b, and IgG3 antibodies. (g,h) Frequencies of total (NP26) and high-affinity (NP4) NP-specific-IgG1 secreting cells (ASCs) in spleen 42 days after primary immunization (g) and day 5 after boost (h). Data are the mean ± SEM of triplicate wells, with four to six mice in each group, and representative of two experiments. **p < 0.01, Mysm1−/−vs. WT.

Mentions: To further investigate antibody responses in Mysm1−/− mice, we used multiple color cytometry of antigen binding and cell surface phenotype to quantify NP+ B cells and plasma cells in Mysm1−/− mice immunized with NP-KLH. Figure 2a,b shows an increase in the frequencies of NP+B220+ B cells and NP+CD138+ plasma cells 14 days after primary intraperitoneal immunization with NP-KLH (100 μg) precipitated in alum. Isotype-switched B cells (IgM−IgD−Gr−1−CD138−B220+) were analyzed for NP+IgG1+ status with NP+IgG1+ cells being subdivided into GC (CD38−) and memory (CD38+) B cells. Figure 2c shows an increase in the CD38+NP+IgG1+ memory B cell population in the immunized Mysm1−/− mice. Frozen spleen sections from WT and Mysm1−/− mice 14 days after immunization with NP-KLH were stained with antibodies to B220 to identify follicles (red) and GL7 for germinal centers (green). Figure 2d shows a defective structural formation in germinal centers of immunized Mysm1−/− mice, although GL7+ cells were observed in immunized Mysm1−/− mice. We further used ELISPOT assays to examine the frequencies of total and high-affinity anti-NP IgG secreting cells in the spleen and bone marrow of immunized WT and Mysm1−/− mice. Figure 2e shows an increase in frequencies of both total and high-affinity anti-NP IgG-secreting cells in immunized Mysm1−/− mice. Higher frequencies of long-term NP-specific IgG-secreting cells were detected and robust recall responses against NL-KLH were elicited in Mysm1−/− mice by a second immunization with NP-KLH (Fig. 2f–h). Thus, we unexpectedly found that primary and recall TD antibody responses are maintained or enhanced in Mysm1−/− mice despite the severe defect in FO B cell development.


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)

Enhanced recall TD antibody responses in Mysm1−/− mice.(a,b) Flow cytometry analysis of splenocytes of WT and Mysm1−/− mice 14 days after intraperitoneal immunization with NP-KLH (100 μg) in alum. PI−CD4−CD8−Gr-1− cells were analyzed for NP+CD138+, NP+B220+, and NP+IgG1+ cells (a). Numbers indicate the percent in each. Absolute cell numbers of NP+B220+ B cells, NP+CD138+ plasma cells, and NP+IgG+ antibody-producing cells per million B220+ cells for each group (n = 5–8 per group) 14 days after primary intraperitoneal immunization with NP-KLH (100 μg) precipitated in alum from one of three independent experiments (b). **P < 0.01, WT vs. Mysm1−/−. (c) Flow cytometry analysis of splenocytes 14 days after intraperitoneal immunization with NP-KLH in alum. Isotype-switched B cells (IgM−IgD−Gr−1−CD138−B220+) were analyzed for NP+IgG1+ status with NP+IgG1+ cells being subdivided into GC (CD38−) and memory (CD38+) B cells. Numbers in plots and histograms represent percentage of cells within the gate. (d) Frozen spleen sections from WT and Mysm1−/− mice 14 days after immunization with NP-KLH, stained with antibodies to B220 to identify follicles (red) and GL7 for germinal centers (green). Original magnification is x10 (top) and x20 (bottom). (e) Frequencies of total (NP26) and high-affinity (NP4) NP-specific-secreting ASCs in spleen and bone marrow examined by ELISOPT assays. Data are the mean ± SEM of triplicate wells, with four to six mice in each group. **P < 0.01, WT vs. Mysm1−/−. (f) Mice were immunized with NP-KLH (100 μg in alum) and boosted with NP-KLH (50 μg in PBS) 42 days later. Serum was collected before boost immunization and 5 days after boost and analyzed by ELISA with NP26-BSA-coated plates for detecting NP-specific IgG1, IgG2a, IgG2b, and IgG3 antibodies. (g,h) Frequencies of total (NP26) and high-affinity (NP4) NP-specific-IgG1 secreting cells (ASCs) in spleen 42 days after primary immunization (g) and day 5 after boost (h). Data are the mean ± SEM of triplicate wells, with four to six mice in each group, and representative of two experiments. **p < 0.01, Mysm1−/−vs. WT.
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f2: Enhanced recall TD antibody responses in Mysm1−/− mice.(a,b) Flow cytometry analysis of splenocytes of WT and Mysm1−/− mice 14 days after intraperitoneal immunization with NP-KLH (100 μg) in alum. PI−CD4−CD8−Gr-1− cells were analyzed for NP+CD138+, NP+B220+, and NP+IgG1+ cells (a). Numbers indicate the percent in each. Absolute cell numbers of NP+B220+ B cells, NP+CD138+ plasma cells, and NP+IgG+ antibody-producing cells per million B220+ cells for each group (n = 5–8 per group) 14 days after primary intraperitoneal immunization with NP-KLH (100 μg) precipitated in alum from one of three independent experiments (b). **P < 0.01, WT vs. Mysm1−/−. (c) Flow cytometry analysis of splenocytes 14 days after intraperitoneal immunization with NP-KLH in alum. Isotype-switched B cells (IgM−IgD−Gr−1−CD138−B220+) were analyzed for NP+IgG1+ status with NP+IgG1+ cells being subdivided into GC (CD38−) and memory (CD38+) B cells. Numbers in plots and histograms represent percentage of cells within the gate. (d) Frozen spleen sections from WT and Mysm1−/− mice 14 days after immunization with NP-KLH, stained with antibodies to B220 to identify follicles (red) and GL7 for germinal centers (green). Original magnification is x10 (top) and x20 (bottom). (e) Frequencies of total (NP26) and high-affinity (NP4) NP-specific-secreting ASCs in spleen and bone marrow examined by ELISOPT assays. Data are the mean ± SEM of triplicate wells, with four to six mice in each group. **P < 0.01, WT vs. Mysm1−/−. (f) Mice were immunized with NP-KLH (100 μg in alum) and boosted with NP-KLH (50 μg in PBS) 42 days later. Serum was collected before boost immunization and 5 days after boost and analyzed by ELISA with NP26-BSA-coated plates for detecting NP-specific IgG1, IgG2a, IgG2b, and IgG3 antibodies. (g,h) Frequencies of total (NP26) and high-affinity (NP4) NP-specific-IgG1 secreting cells (ASCs) in spleen 42 days after primary immunization (g) and day 5 after boost (h). Data are the mean ± SEM of triplicate wells, with four to six mice in each group, and representative of two experiments. **p < 0.01, Mysm1−/−vs. WT.
Mentions: To further investigate antibody responses in Mysm1−/− mice, we used multiple color cytometry of antigen binding and cell surface phenotype to quantify NP+ B cells and plasma cells in Mysm1−/− mice immunized with NP-KLH. Figure 2a,b shows an increase in the frequencies of NP+B220+ B cells and NP+CD138+ plasma cells 14 days after primary intraperitoneal immunization with NP-KLH (100 μg) precipitated in alum. Isotype-switched B cells (IgM−IgD−Gr−1−CD138−B220+) were analyzed for NP+IgG1+ status with NP+IgG1+ cells being subdivided into GC (CD38−) and memory (CD38+) B cells. Figure 2c shows an increase in the CD38+NP+IgG1+ memory B cell population in the immunized Mysm1−/− mice. Frozen spleen sections from WT and Mysm1−/− mice 14 days after immunization with NP-KLH were stained with antibodies to B220 to identify follicles (red) and GL7 for germinal centers (green). Figure 2d shows a defective structural formation in germinal centers of immunized Mysm1−/− mice, although GL7+ cells were observed in immunized Mysm1−/− mice. We further used ELISPOT assays to examine the frequencies of total and high-affinity anti-NP IgG secreting cells in the spleen and bone marrow of immunized WT and Mysm1−/− mice. Figure 2e shows an increase in frequencies of both total and high-affinity anti-NP IgG-secreting cells in immunized Mysm1−/− mice. Higher frequencies of long-term NP-specific IgG-secreting cells were detected and robust recall responses against NL-KLH were elicited in Mysm1−/− mice by a second immunization with NP-KLH (Fig. 2f–h). Thus, we unexpectedly found that primary and recall TD antibody responses are maintained or enhanced in Mysm1−/− mice despite the severe defect in FO B cell development.

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