B Cell Development and the Splenic Microenvironment in Dlk-1 Deficient Mice

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1251-1251
Author(s):  
Heba A Degheidy ◽  
Allison L Branchaw ◽  
Lucy C Bauer ◽  
Steven R Bauer
Keyword(s):  
B Cells ◽  
B Cell ◽  
Stromal Cells ◽  
Stromal Cell ◽  
Cell Development ◽  
B Cell Development ◽  
Stroma Cell ◽  
Cell Fractions ◽  
And Function ◽  
Deficient Mice

Abstract Abstract 1251 Background: DLK-1 is a transmembrane and secreted protein that plays a crucial role in normal B cell development and differentiation. In a previous study we showed that DLK-1 knockout mice (Dlk1−/− mice (KO)) have distinct differences in B cell fractions in the spleen and bone marrow compared to wild-type Dlk1+/+ (WT) mice. KO mice showed a decrease in follicular (FO) B cells and an increase in the size of the marginal zone (MZ) and number of MZ B cells in the spleen of 8 week old mice. Furthermore, there was an exaggerated primary T-dependent antigen-specific humoral immune response. The mechanisms underlying the changes in splenic B cell fractions between KO and WT mice are not yet clear. It has been suggested that stromal microenvironmental cells form distinct cellular niches that influence different stages of B cell development. Alterations in these stromal niches due to absence of DLK-1 may be an underlying cause of the observed splenic B cell fraction alterations. It was previously shown that Galectin-1 (GAL1) plays an important role in the bone marrow microenvironment and affects proliferation and differentiation of normal mouse pre-BII cells (Blood April 21, 2011). This study is designed to investigate the splenic stromal cells in DLK-1 deficient mice as a step toward understanding these B cell alterations, and to test whether the stromal cell derived-GAL1 influences splenic B-cell development. Methods: For detection of B cell fractions, a multicolor flow cytometry panel consisting of anti-IgD/IgM/CD23/CD93/CD45R/CD21/CD35 was used. B cell fractions were identified as follows: MZ (CD23neg-low, CD21high), FO (CD23high, CD21intermediate), Tr1 (CD23neg, CD21neg, AA4.1pos, B220pos), Tr2 (CD23pos, AA4.1pos, B220pos). For detection of stromal cell fractions, an anti-CD11c/Ter119/CD19/Gr-1/Tie-2/CD45/CD31/CD117/CD34 panel was used. Stromal cells were identified as follows: CD45neg, lineage− (Ter119, CD19, GR1, CD11c, and CD34), CD117neg, CD34neg, Tie2neg. Two stromal cell fractions were detected: CD31 +and CD31−. Galectin-1 expression was evaluated on CD31+ and CD31−stroma cell fractions. An eight color flow cytometric panel consisting of antibody directed to MHC II, CD11c, Gr-1, CD8a, B220, and CD11b was used to evaluate myeloid, lymphoid and plasmacytoid dendritic cell fractions. Results: Our data showed an increase in MZ B-cells (p<0.005) and a decrease in FO B cells (p<0.005) in the KO mice. When looking at the splenic stromal cells, we found an increase in the CD31+ fraction and a decrease in the CD31- fraction in KO mice compared to WT mice (p<0.005). We observed that the CD31 + stromal cell expressed high galectin-1 (GAL1) levels compared to CD31− stroma cells. Also there was an increased percentage of myeloid dendritic cells in KO compared to WT (p< 0.05). Conclusion: We have shown that absence of DLK-1 leads to alterations in splenic stromal populations and that these may play an important role in altered B cell populations and function observed in DLK-1-deficient mice. We are investigating whether the CD31+ GAL1 +stroma cell is a key stroma cell that plays a critical role in splenic B cell development and is responsible for the B-lineage differences seen in DLK-1-deficient mice. Our observation that there is an increase in the myeloid dendritic cell fraction may explain the exaggerated primary immune response seen in the KO mice. These data show that DLK-1-deficiency leads to several changes in the splenic cellular microenvironment and suggest that these changes contribute to alterations in B-cell development and function. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Single and Combined Deletions of the NTAL/LAB and LAT Adaptors Minimally Affect B-Cell Development and Function

2005 ◽  
Vol 25 (11) ◽  
pp. 4455-4465 ◽  
Author(s):  
Ying Wang ◽  
Ondrej Horvath ◽  
Andrea Hamm-Baarke ◽  
Mireille Richelme ◽  
Claude Grégoire ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cell Development ◽  
B Cell Development ◽  
And Function ◽  
Deficient Mice

ABSTRACT NTAL (non-T-cell activation linker, also called LAB) and LAT (linker for activation of T cells) are evolutionarily related transmembrane adaptor proteins that are phosphorylated upon immunoreceptor engagement. Using quantitative reverse transcription-PCR, both NTAL and LAT were found to be expressed in B cells. However, LAT expression was limited to early B cells, whereas NTAL expression typified mature B cells. To delineate their roles in B-cell development and function, Ntal-deficient mice were generated and crossed with Lat-deficient mice. B cells developed in Lat −/− Ntal −/− double-deficient mice and in mice lacking either of the two adaptors with the same efficiency as in wild-type mice. Upon B-cell antigen receptor cross-linking, Ntal −/− B cells exhibited slightly increased Ca2+ mobilization and proliferation. In addition, Ntal-deficient mice had increased levels of natural antibodies and slightly increased humoral response to a T-dependent antigen. Normal titers of serum-specific immunoglobulins were produced in response to a T-cell-independent antigen. Although NTAL is also expressed in plasma cells, its absence did not affect the hypergammaglobulinemia E and G1 that developed in mice with a mutation in tyrosine 136 of LAT. Therefore, NTAL does not play a role in B cells symmetric to the role played by LAT in T cells.

Loss of IP3 Receptor–Mediated Ca2+ Release in Mouse B Cells Results in Abnormal B Cell Development and Function

2017 ◽  
Vol 199 (2) ◽  
pp. 570-580 ◽  
Author(s):  
Huayuan Tang ◽  
Hong Wang ◽  
Qingsong Lin ◽  
Feifei Fan ◽  
Fei Zhang ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Development ◽  
B Cell Development ◽  
Ip3 Receptor ◽  
And Function

scholarly journals Essential Immunoregulatory Role for BCAP in B Cell Development and Function

2002 ◽  
Vol 195 (5) ◽  
pp. 535-545 ◽  
Author(s):  
Tetsuo Yamazaki ◽  
Kiyoshi Takeda ◽  
Kumiko Gotoh ◽  
Hiroshi Takeshima ◽  
Shizuo Akira ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Receptor ◽  
Cell Development ◽  
B Cell Development ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Phosphoinositide 3 Kinase ◽  
And Function ◽  
B Cell Deficiency

BCAP was recently cloned as a binding molecule to phosphoinositide 3-kinase (PI3K). To investigate the role of BCAP, mutant mice deficient in BCAP were generated. While BCAP-deficient mice are viable, they have decreased numbers of mature B cells and B1 B cell deficiency. The mice produce lower titers of serum immunoglobulin (Ig)M and IgG3, and mount attenuated responses to T cell–independent type II antigen. Upon B cell receptor cross-linking, BCAP-deficient B cells exhibit reduced Ca2+ mobilization and poor proliferative responses. These findings demonstrate that BCAP plays a pivotal immunoregulatory role in B cell development and humoral immune responses.

scholarly journals bcl-x exhibits regulated expression during B cell development and activation and modulates lymphocyte survival in transgenic mice.

1996 ◽  
Vol 183 (2) ◽  
pp. 381-391 ◽  
Author(s):  
D A Grillot ◽  
R Merino ◽  
J C Pena ◽  
W C Fanslow ◽  
F D Finkelman ◽  
...  
Keyword(s):  
B Cells ◽  
Transgenic Mice ◽  
B Cell ◽  
Cell Lineage ◽  
Cell Development ◽  
B Cell Development ◽  
Immunoglobulin M ◽  
Protective Mechanism ◽  
And Function ◽  
Peripheral B Cells

We have assessed during B cell development, the regulation and function of bcl-x, a member of the bcl-2 family of apoptosis regulatory genes. Here we show that Bcl-xL, a product of bcl-x, is expressed in pre-B cells but downregulated at the immature and mature stages of B cell development. Bcl-xL but not Bcl-2 is rapidly induced in peripheral B cells upon surface immunoglobulin M (IgM) cross-linking, CD40 signaling, or LPS stimulation. Transgenic mice that overexpressed Bcl-xL within the B cell lineage exhibited marked accumulation of peripheral B cells in lymphoid organs and enhanced survival of developing and mature B cells. B cell survival was further increased by simultaneous expression of bcl-xL and bcl-2 transgenes. These studies demonstrate that Bcl-2 and Bcl-xL are regulated differentially during B cell development and activation of mature B cells. Induction of Bcl-xL after signaling through surface IgM and CD40 appears to provide mature B cells with an additional protective mechanism against apoptotic signals associated with antigen-induced activation and proliferation.

scholarly journals Differential Regulation of B Cell Development, Activation, and Death by the Src Homology 2 Domain–Containing 5′ Inositol Phosphatase (Ship)

2000 ◽  
Vol 191 (9) ◽  
pp. 1545-1554 ◽  
Author(s):  
Anne Brauweiler ◽  
Idan Tamir ◽  
Joseph Dal Porto ◽  
Robert J. Benschop ◽  
Cheryl D. Helgason ◽  
...  
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
B Cell ◽  
Cell Development ◽  
B Cell Development ◽  
Inositol Phosphatase ◽  
Src Homology 2 ◽  
Src Homology ◽  
Src Homology 2 Domain ◽  
Deficient Mice

Although the Src homology 2 domain–containing 5′ inositol phosphatase (SHIP) is a well-known mediator of inhibitory signals after B cell antigen receptor (BCR) coaggregation with the low affinity Fc receptor, it is not known whether SHIP functions to inhibit signals after stimulation through the BCR alone. Here, we show using gene-ablated mice that SHIP is a crucial regulator of BCR-mediated signaling, B cell activation, and B cell development. We demonstrate a critical role for SHIP in termination of phosphatidylinositol 3,4,5-triphosphate (PI[3,4,5]P3) signals that follow BCR aggregation. Consistent with enhanced PI(3,4,5)P3 signaling, we find that splenic B cells from SHIP-deficient mice display enhanced sensitivity to BCR-mediated induction of the activation markers CD86 and CD69. We further demonstrate that SHIP regulates the rate of B cell development in the bone marrow and spleen, as B cell precursors from SHIP-deficient mice progress more rapidly through the immature and transitional developmental stages. Finally, we observe that SHIP-deficient B cells have increased resistance to BCR-mediated cell death. These results demonstrate a central role for SHIP in regulation of BCR signaling and B cell biology, from signal driven development in the bone marrow and spleen, to activation and death in the periphery.

scholarly journals Iκb Kinase α Is Essential for Mature B Cell Development and Function

2001 ◽  
Vol 193 (4) ◽  
pp. 417-426 ◽  
Author(s):  
Tsuneyasu Kaisho ◽  
Kiyoshi Takeda ◽  
Tohru Tsujimura ◽  
Taro Kawai ◽  
Fumiko Nomura ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Fetal Liver ◽  
Cell Development ◽  
B Cell Development ◽  
Cytokine Signaling ◽  
Iκb Kinase ◽  
And Function

IκB kinase (IKK) α and β phosphorylate IκB proteins and activate the transcription factor, nuclear factor (NF)-κB. Although both are highly homologous kinases, gene targeting experiments revealed their differential roles in vivo. IKKα is involved in skin and limb morphogenesis, whereas IKKβ is essential for cytokine signaling. To elucidate in vivo roles of IKKα in hematopoietic cells, we have generated bone marrow chimeras by transferring control and IKKα-deficient fetal liver cells. The mature B cell population was decreased in IKKα−/− chimeras. IKKα−/− chimeras also exhibited a decrease of serum immunoglobulin basal level and impaired antigen-specific immune responses. Histologically, they also manifested marked disruption of germinal center formation and splenic microarchitectures that depend on mature B cells. IKKα−/− B cells not only showed impairment of survival and mitogenic responses in vitro, accompanied by decreased, although inducible, NF-κB activity, but also increased turnover rate in vivo. In addition, transgene expression of bcl-2 could only partially rescue impaired B cell development in IKKα−/− chimeras. Taken together, these results demonstrate that IKKα is critically involved in the prevention of cell death and functional development of mature B cells.

scholarly journals Complete Block of Early B Cell Differentiation in Mice Lacking the Endosomal Adaptor Protein p14

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1026-1026
Author(s):  
Marcin Lyszkiewicz ◽  
Daniel Kotlarz ◽  
Natalia Zietara ◽  
Gudrun Brandes ◽  
Jana Diestelhorst ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Target Genes ◽  
Conflicts Of Interest ◽  
Adaptor Protein ◽  
Cell Development ◽  
B Cell Development ◽  
B Cell Differentiation ◽  
Knock Out ◽  
And Function

Abstract Human primary immunodeficiency caused by a point mutation in the 3' untranslated region of the endosomal adaptor protein p14 (also known as Lamtor2) resulted in severely impaired function of neutrophils, B cells, T cells and melanocytes. However, complexity of the phenotype and scarcity of human material preclude in-depth studies. Therefore, to gain insight into the role of p14 in B cell development and function, we generated loxP conditional knock-out mice. Using mb-1-Cre mice we demonstrated that loss of p14 at the preB1 stage lead to a complete block of B cell development, resulting in the absence of IgM-positive B cells. Further, to test the significance of p14 deficiency in peripheral organs, we took advantage of CD19-Cre mice, which have limited efficiency in deleting target genes in the bone marrow, but reach up to 95% efficiency in spleen. Thus, we could demonstrate that later in B cell development, p14 was essential for the generation and activation of mature B lymphocytes. While B1 cell development was maintained, splenic follicular B cells were massively reduced in the absence of p14. Furthermore, activation of B cell receptor (BCR) resulted in impaired intracellular signalling and proliferation of p14 deficient B cells. In particular, lack of p14 lead to delayed internalization of BCR and endosomal processing associated with impaired mobilization of Ca++ from intracellular stores as well as aberrant phosphorylation of BCR-associated kinases. In conclusion, our data revealed that p14 is a critical regulator of B cell development and function, which acts by modulating BCR signalling. Disclosures No relevant conflicts of interest to declare.

G-CSF-Induced Alterations in the Bone Marrow Microenvironment Suppress B Lymphopoiesis

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1246-1246
Author(s):  
Ryan B. Day ◽  
Adam Greenbaum ◽  
Daniel C. Link
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
B Cell ◽  
Stromal Cells ◽  
Cell Development ◽  
B Cell Development ◽  
Bone Marrow Microenvironment ◽  
B Lymphopoiesis ◽  
Treatment Results ◽  
Cell Suppression

Abstract Abstract 1246 Infectious stress is associated with a shift in the bone marrow from lymphopoiesis to granulopoiesis. Expression of granulocyte colony-stimulating factor (G-CSF), the principal cytokine regulating granulopoiesis, is often induced during infection. We previously reported that G-CSF treatment is associated with marked suppression of B lymphopoiesis in murine bone marrow. After 5 days of G-CSF treatment (250 μg/kg), total B cells in the bone marrow were reduced 8.1 ± 0.9-fold. Pre-pro-B cells were reduced 1.6 ± 0.3-fold, pro-B cells 12.4 ± 1.9-fold, pre-B cells 5.6 ± 0.8-fold, immature B cells 7.5 ± 1.2-fold, and mature naïve B cells 83 ± 7.6-fold. B-committed lymphoid progenitors (BLP) were modestly but significantly decreased (1.4 ± 0.2-fold), while common lymphoid progenitors (CLP) were not affected by G-CSF treatment. Increased apoptosis of mature naïve B cells in the bone marrow was observed. Studies of G-CSF receptor deficient (Csf3r−/−) bone marrow chimeras show that G-CSF acts in a non-cell intrinsic fashion to suppress B lymphopoiesis. Consistent with this observation, we show that G-CSF treatment results in decreased expression in the bone marrow microenvironment of multiple B-supportive factors including CXCL12, interleukin-6, interleukin-7, and B cell activating factor (BAFF). Prior studies have established that CXCL12-abundant reticular (CAR) cells in the bone marrow play a key role in B cell development. CAR cells are perivascular stromal cells that express very high levels of CXCL12 and are in direct contact with pre-pro-B cells. G-CSF treatment did not affect CAR cell number. However, RNA expression profiling of sorted CAR cells showed that expression of several genes associated with B cell development are significantly decreased by G-CSF, including CXCL12 (4.2 ± 1.5-fold). In addition to CAR cells, other stromal cells in the bone marrow express CXCL12, including osteoblasts and endothelial cells. To assess the role of CXCL12 production by each of these cell types to B lymphopoiesis, we generated Cxcl12flox mice and crossed them with mice expressing the following tissue-specific Cre-recombinase transgenes: Osteocalcin-Cre (Oc-Cre) targeting mature mineralizing osteoblasts; Osterix-Cre (Osx-Cre) targeting CAR cells and all osteolineage cells; or Prx1-Cre targeting mesenchymal progenitors and their progeny. Deletion of Cxcl12 using Oc-Cre or Osx-Cre had a similar effect on B cell development, with an isolated loss of mature naïve B cells in the bone marrow (2.7 ± 0.5 and 4.1 ± 1.7-fold, respectively). In contrast, deletion of Cxcl12 using Prx1-Cre resulted in severe suppression of B lymphopoiesis that included a loss of CLP (3.3 ± 2.0-fold), BLP (5.6 ± 4.3-fold), and pre-pro-B cells (12.4 ± 5.1-fold). Interestingly, treatment of Prx1-Cre Cxcl12flox/- mice with G-CSF resulted in additional B cell loss, indicating that deletion of Cxcl12 in mesenchymal stromal cells is not sufficient to fully recapitulate G-CSF-induced B cell suppression. In summary, G-CSF treatment results in marked changes in the bone marrow microenvironment that lead to a suppression of B lymphopoiesis. While G-CSF-induced inhibition of CXCL12 expression from stromal cells contributes to B cell suppression, additional alterations in the microenvironment also contribute to this phenotype. Disclosures: No relevant conflicts of interest to declare.

Perturbation of B-cell development in mice overexpressing the Bcl-2 homolog A1

Blood ◽  
2002 ◽  
Vol 99 (9) ◽  
pp. 3350-3359 ◽  
Author(s):  
Peter I. Chuang ◽  
Samantha Morefield ◽  
Chien-Ying Liu ◽  
Stephen Chen ◽  
John M. Harlan ◽  
...  
Keyword(s):  
Immune System ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
System Development ◽  
Cell Development ◽  
B Cell Development ◽  
Lymphoid Cells ◽  
Immune System Development ◽  
And Function

Abstract Decisions about cell survival or death are central components of adaptive immunity and occur at several levels in immune system development and function. The Bcl-2 family of homologous proteins plays an important role in these decisions in lymphoid cells. Bcl-2, Bcl-xL, and A1 are differentially expressed during B- and T-cell development, and they have shared and distinct roles in regulating cell death. We sought to gain insight into the role of A1 in immune system development and function. A murine A1-a transgene was expressed under the control of the Eμ enhancer, and mice with A1 overexpression in B- and T-cell lineages were derived. Thymocytes and early B cells in Eμ-A1 mice showed extended survival. B-lineage development was altered, with expansion of the pro–B cell subset at the expense of pre–B cells, suggesting an impairment of the pro– to pre–B-cell transition. This early B-cell phenotype resembled Eμ–Bcl-xL mice but did not preferentially rescue cells with completed V(D)J rearrangements of the immunoglobulin heavy chain. In contrast to Eμ–Bcl-2 transgenes, A1 expression in pro–B cells did not rescue pre–B-cell development in SCID mice. These studies indicate that A1 protects lymphocytes from apoptosis in vitro but that it has lineage- and stage-specific effects on lymphoid development. Comparison with the effects of Bcl-2 and Bcl-xL expressed under similar control elements supports the model that antiapoptotic Bcl-2 homologs interact differentially with intracellular pathways affecting development and apoptosis in lymphoid cells.

Critical role of class IA PI3K for c-Rel expression in B lymphocytes

Blood ◽  
2009 ◽  
Vol 113 (5) ◽  
pp. 1037-1044 ◽  
Author(s):  
Satoshi Matsuda ◽  
Yohei Mikami ◽  
Masashi Ohtani ◽  
Mari Fujiwara ◽  
Yasuko Hirata ◽  
...  
Keyword(s):  
B Cell ◽  
Critical Role ◽  
Cell Development ◽  
B Cell Development ◽  
Transcription Factor Family ◽  
Cell Functions ◽  
Pi3k Activity ◽  
And Function ◽  
Deficient Mice

AbstractThe fact that the Xid mutation of Btk impairs the ability of pleckstrin homo-logy domain of Btk to bind phosphatidylinositol-(3,4,5)-trisphosphate, a product of class IA phosphoinositide-3 kinases (PI3Ks), has been considered strong evidence for the hypothesis that Btk functions downstream of PI3Ks. We demonstrate here that the Xid mutation renders the Btk protein unstable. Furthermore, class IA PI3K- and Btk-deficient mice show different phenotypes in B-cell development, collectively indicating that PI3Ks and Btk differentially function in BCR signal transduction. Nevertheless, both PI3K and Btk are required for the activation of NF-κB, a critical transcription factor family for B-cell development and function. We demonstrate that PI3Ks maintain the expression of NF-κB proteins, whereas Btk is known to be essential for IκB degradation and the translocation of NF-κB to the nucleus. The loss of PI3K activity results in marked reduction of c-Rel and to a lesser extent RelA expression. The lentivirus-mediated introduction of c-Rel corrects both developmental and proliferative defects in response to BCR stimulation in class IA PI3K-deficient B cells. These results show that the PI3K-mediated control of c-Rel expression is essential for B-cell functions.

Sign in / Sign up

Export Citation Format

Share Document