Dataset Information

Basal immunoglobulin signaling actively maintains developmental stage in immature B cells.

ABSTRACT: In developing B lymphocytes, a successful V(D)J heavy chain (HC) immunoglobulin (Ig) rearrangement establishes HC allelic exclusion and signals pro-B cells to advance in development to the pre-B stage. A subsequent functional light chain (LC) rearrangement then results in the surface expression of IgM at the immature B cell stage. Here we show that interruption of basal IgM signaling in immature B cells, either by the inducible deletion of surface Ig via Cre-mediated excision or by incubating cells with the tyrosine kinase inhibitor herbimycin A or the phosphatidylinositol 3-kinase inhibitor wortmannin, led to a striking "back-differentiation" of cells to an earlier stage in B cell development, characterized by the expression of pro-B cell genes. Cells undergoing this reversal in development also showed evidence of new LC gene rearrangements, suggesting an important role for basal Ig signaling in the maintenance of LC allelic exclusion. These studies identify a previously unappreciated level of plasticity in the B cell developmental program, and have important implications for our understanding of central tolerance mechanisms.

SUBMITTER: Tze LE

PROVIDER: S-EPMC1059451 | biostudies-literature | 2005 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Basal immunoglobulin signaling actively maintains developmental stage in immature B cells.

Tze Lina E LE Schram Brian R BR Lam Kong-Peng KP Hogquist Kristin A KA Hippen Keli L KL Liu Jiabin J Shinton Susan A SA Otipoby Kevin L KL Rodine Peter R PR Vegoe Amanda L AL Kraus Manfred M Hardy Richard R RR Schlissel Mark S MS Rajewsky Klaus K Behrens Timothy W TW

PLoS biology 20050308 3

In developing B lymphocytes, a successful V(D)J heavy chain (HC) immunoglobulin (Ig) rearrangement establishes HC allelic exclusion and signals pro-B cells to advance in development to the pre-B stage. A subsequent functional light chain (LC) rearrangement then results in the surface expression of IgM at the immature B cell stage. Here we show that interruption of basal IgM signaling in immature B cells, either by the inducible deletion of surface Ig via Cre-mediated excision or by incubating ce ...[more]

PMID: 15752064

Similar Datasets

Project description:This series represent several subgroups of experiments designed to investigate the role of basal immunoglobulin signaling in immature B cell development. The first subgroup of arrays (Ctrl Mhi, Cre Mhi, Cre Mlo) was done to identify the changes in gene expression in immature B cells as a consequence of inducible deletion of surface IgM expression via Cre-LoxP mediated excision of Ig heavy chain. The second subgroup of arrays (GFPneg, GFPpos, FxE Ctrl, FxE HA) was done to identify the changes in gene expression in immature B cells as a consequence of blockade of tyrosine kinase signaling with herbimycin A treatment. The third subgroup of arrays (FxD, FxE, B6 Mneg, HEL Mhi) was done to establish gene expression profiles of immature B, pre B and pro B cells as reference platforms for the other two subgroups. (Tze etal. Public Library of Science Biology, 2005) The appended supplementary tables are described as follows: TABLE 1: Transformed array signal intensities used for statistical analysis. Listed are all probe sets excluding masked probe sets and Affymetrix hybridization control probe sets. Results are based on the following definitions: - Values with detection p values <0.1 were considered present. - Signal intensities with detection = "A" or with values < 20 were set to "20". TABLE 2: Genes differentially expressed between Ctrl Mhi and Cre Mlo cell populations and associated signal values. Results are based on the following definitions: - 2-fold or greater difference in means - difference in mean expression values > 200 - P < 0.01 (by Student's T test) TABLE 3: Probesets used for clustering in Figures 2 and 3 of publication TABLE 4: Probesets used for clustering in Figure 7 of publication TABLE 5: Correlation coefficients between all cell populations. Correlation coefficients were calculated as an additional method to demonstrate the relationship of the various cell populations to each other. Shown are the correlation coefficients generated using the mean expression values for each of the 101 transcripts from Figure 7 of publication. Keywords = bone marrow B cells

Project description:Background: Cardiac kinases play a critical role in the development of heart failure, and represent potential tractable therapeutic targets. However, only a very small fraction of the cardiac kinome has been investigated. To identify novel cardiac kinases involved in heart failure, we employed an integrated transcriptomics and bioinformatics analysis and identified Homeodomain-Interacting Protein Kinase 2 (HIPK2) as a novel candidate kinase. The role of HIPK2 in cardiac biology is unknown. Methods: We used the Expression2Kinase algorithm for the screening of kinase targets. To determine the role of HIPK2 in the heart, we generated cardiomyocyte-specific HIPK2 knockout (CM-KO) and heterozygous (CM-Het) mice. Heart function was examined by echocardiography and related cellular and molecular mechanisms were examined. Adeno-associated virus serotype 9 (AAV9) carrying cardiac-specific constitutively active MEK1 (TnT-MEK1-CA) were administrated to rescue cardiac dysfunction in CM-KOs. Results: To our knowledge, this is the first study to define the role of HIPK2 in cardiac biology. Using multiple HIPK2 loss-of-function mouse models, we demonstrated that reduction of HIPK2 in cardiomyocytes leads to cardiac dysfunction—suggesting a causal role in heart failure. Importantly, cardiac dysfunction in HIPK2 KOs developed with advancing age, but not during development. In addition, CM-KO and CM-Het exhibited a gene dose-response relationship of cardiomyocyte HIPK2 on heart function. HIPK2 expression in the heart was significantly reduced in human end-stage ischemic cardiomyopathy compared to non-failing myocardium, suggesting a clinical relevance of HIPK2 in cardiac biology. In vitro studies with neonatal rat ventricular cardiomyocytes corroborated the in vivo findings. Specifically, adenovirus-mediated overexpression of HIPK2 suppressed the expression of heart failure markers, NPPA and NPPB, at basal condition and abolished phenylephrine-induced pathological gene expression. An array of mechanistic studies revealed impaired ERK1/2 signaling in HIPK2 deficient hearts. In vivo rescue experiment with AAV9 TnT-MEK1-CA nearly abolished the detrimental phenotype of KOs suggesting that impaired ERK signaling mediated apoptosis as the key factor driving the detrimental phenotype in CM-KO hearts. Conclusions: Taken together, these findings suggest that cardiomyocyte HIPK2 is required to maintain normal cardiac function via ERK signaling

Dataset Information

Basal immunoglobulin signaling actively maintains developmental stage in immature B cells.

Publications

Basal immunoglobulin signaling actively maintains developmental stage in immature B cells.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets