Transcriptional and metabolic pre-B cell receptor-mediated checkpoints: Implications for autoimmune diseases

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Contents lists available at ScienceDirect

Molecular Immunology

j ourna l ho me pa ge: www.elsev ier .com/ locate /mol imm

ranscriptional and metabolic pre-B cell receptor-mediatedheckpoints: Implications for autoimmune diseases

oncef Zouali a,b,∗

Inserm, UMR 1132, F-75475 Paris, FranceUniversité Paris Diderot, Sorbone Paris Cité, F-75475 Paris, France

r t i c l e i n f o

rticle history:eceived 19 November 2013eceived in revised form 10 January 2014ccepted 13 January 2014vailable online xxx

eywords:olerancenergyeceptor editingAPTMS

a b s t r a c t

At the pre-B cell stage of lymphocyte development, immunoglobulin light-chains are not yet produced,and heavy-chains are covalently linked to surrogate light-chains composed of VpreB and �5 to formthe pre-B cell receptor (pre-BCR) in a non-covalent association with signal-transducing modules. Eventough the pre-BCR does not have the potential to bind conventional antigens, accumulating evidenceindicates that pre-BCR-mediated checkpoints are important both for negative and positive selection ofself-reactivity, and that defects in these regulatory nodes may be associated with autoimmune disease.Thus, the transcription factor BACH2, which represents a susceptibility locus for rheumatoid arthritis,has recently emerged as a crucial mediator of negative selection at a pre-BCR checkpoint. The lysosome-associated protein LAPTM5, which is highly expressed in an animal model of Sjögren’s syndrome, playsa role in down-modulation of the pre-BCR. Studies of copy number variation in rheumatoid arthritis

ach-2RF4RF8ositive selectionegative selectionalectin-1

suggest that a reduced dosage of the VPREB1 gene is involved in disease pathogenesis. Notably, animalmodels of autoimmune disease exhibit defects in pre-B to naïve B cell checkpoints. Administration of apre-BCR ligand, which also plays a role in anergy both in human and murine B lymphocytes, amelioratesdisease in experimental models of autoimmunity. Further investigation is required to gain a better insightinto the molecular mechanisms of pre-BCR-mediated checkpoints and to determine their relevance toautoimmune diseases.

. Introduction

In the adult bone marrow (BM), B lymphocytes develop fromluripotent hematopoietic stem cells through an ordered pro-ess that involves differential expression of cell-surface markers,equential rearrangement of immunoglobulin (Ig) heavy (H) andight chain (L) gene loci, and expression of stage-specific genesMelchers, 2005; Sakaguchi and Melchers, 1986). At the progenitorpro-)/precursor (pre-) BI cell stage, the cells have initiated expres-ion of the Ig surrogate L-chain (SLC) consisting of the VpreB and5 chains. At the pre-BII stage, they express the pre-B cell receptor

pre-BCR) composed of the newly rearranged and synthesized H-hain and the SLC on the cell surface. Importantly, not all rearranged-chains can pair with the SLC to form a pre-BCR. In mice, only half

Please cite this article in press as: Zouali, M., Transcriptional and metaautoimmune diseases. Mol. Immunol. (2014), http://dx.doi.org/10.101

f the in-frame rearranged H-chains pair productively with SLCsten Boekel et al., 1997), and only B cells that express an H-chainapable of pairing with the SLC undergo clonal expansion (Hess

∗ Corresponding author at: Inserm; University Paris 7, Inserm, UMR 1132, Centreiggo Petersen, Hôpital Lariboisière, 2, rue Ambroise Pare, 75475 Paris Cedex 10,rance. Tel.: +33 1 49 95 63 31/+33 1 49 95 63 28; fax: +33 1 49 95 84 52.

E-mail address: [email protected]

161-5890/$ – see front matter © 2014 Elsevier Ltd. All rights reserved.ttp://dx.doi.org/10.1016/j.molimm.2014.01.009

© 2014 Elsevier Ltd. All rights reserved.

et al., 2001). After expansion of pre-BII cells, expression of the SLCvanishes as pre-B cells develop into immature B cells that expressIgM on the surface as the BCR. Then, cells exit the BM and migrateto peripheral lymphoid organs where they mature and take partin humoral immune responses. Several observations indicate thatpre-BCR-mediated checkpoints are important both for negative andpositive selection of self-reactivity. This review will discuss thepotential implications of these checkpoints to our understandingof autoimmunity (Fig. 1).

2. Transcriptional regulation of pre-B cells andautoimmunity

In the mouse, transgenic expression of SLC componentsthroughout B cell development does not alter pre-B cell prolifer-ation and differentiation, results in deletion of immature B cells,and induces constitutive BCR signaling and activation of mature Bcells (van Loo et al., 2007). Notably, the presence of SLC induces asignificant amount of secondary rearrangements of endogenous Ig

bolic pre-B cell receptor-mediated checkpoints: Implications for6/j.molimm.2014.01.009

L-chain loci (van Loo et al., 2007); and silencing of SLC genes doesnot seem to be essential for the limitation of pre-B cell proliferation,but is required for the prevention of constitutive B cell activation(Melchers, 2005). The signals that regulate pre-B cell expansion

dx.doi.org/10.1016/j.molimm.2014.01.009


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ig. 1. Pre-B cell receptor-mediated checkpoints and autoimmunity. Shown is a schemo immune tolerance to self.

re not completely understood. Primary pre-B cells were showno be subject to a broad feedback inhibition of pre-BCR signalingomponents (Hauser et al., 2013). In addition, Interferon regulatoryactors (IRFs) also seem to play a role. IRF4 and 8 are structurallyelated, hematopoietic cell-specific transcription factors that coop-ratively regulate the differentiation of B cells. A series of studiesave established an additional role for IRF4 and 8 as essential regu-

ators of B cell development. They have been shown to be critical forre-B cell development, receptor editing, germinal center reaction,nd plasma cell differentiation (Lu et al., 2003). For example, B cellevelopment is almost completely blocked at the large pre-B celltage in IRF4 and 8 compound mutant mice (Irf4,8−/−). Moreover,RF4 and IRF8 were found to be sufficient individually to rescue theevelopment of Irf4,8−/− pre-B cells, confirming that they functionedundantly in pre-B cell development (Ma et al., 2006). Interest-ngly, Irf4,8−/− pre-B cells are hyperproliferative, suggesting thatRF4 and 8 negatively regulate pre-B cell proliferation. They areritical not only for L-chain rearrangements, but also for limitingre-B cell expansion.

Analysis of a heterozygous mutant mouse, in which the NF-appaB-dependent I-kappa-b-alpha gene was replaced with a Laczeporter complementary DNA, allowed detection of a subpopula-ion of pre-B cells that contain active nuclear NF-�B and expressncreased levels of various markers of receptor editing (Caderat al., 2009). Intestingly, Irf4 transcripts were up-regulated in there-B cells of the mutant mice. Since IRF4 is a target of NF-�Bnd is required for receptor editing, it is possible that NF-�Bould act through IRF4 to regulate receptor editing. The cor-elation between NF-�B and IRF4 activity, and receptor editingay indicate a functional role for these transcription factors in

elf-tolerance. As regards Irf8, mice deficient in this transcrip-ion factor, both germline and conditional knockout, producednti-dsDNA antibodies, and B cell anergy was breached in therf8-deficient mice (Pathak et al., 2013). However, the effectsn pre-B cells were not determined. Since several observationshowed that receptor editing and L-chain gene rearrangementsre defective in B cells of patients with autoimmune diseaseRadic and Zouali, 1996; Zouali, 2008), it will be of interest


o probe the contribution of IRF4 and 8 to receptor editing inutoimmunity.

It has been estimated that the murine BM produces approxi-ately 106 pre-B cells daily (Osmond, 1991), most of which will

ew of the structure of the pre-B receptor, and its major potential functions in regard

die unless they undergo productive VH-DJH gene rearrangementsfollowed by pre-BCR signaling and transition into the long-livedperipheral B cell pool (Melchers, 2005). Fidelity of the B cellrepertoire is maintained by negative selection of pre-B cells withnonfunctional Ig H-chains that precedes the survival of thoseexpressing functional rearrangements. Pre-B cells that have pro-ductively rearranged VH-DJH gene segments and emerged from thepre-BCR checkpoint are rescued by BCL6, a transcriptional repres-sor that acts as a crucial survival factor (Nahar et al., 2011). Inaddition, BACH2 has recently emerged as a crucial mediator ofnegative selection at the pre-BCR checkpoint (Swaminathan et al.,2013). In normal pre-B cells, BACH2-mediated activation of p53is opposed by BCL6, which is a potent transcriptional repressorof p53. While the role of BACH2 in B cell tolerance remains to beinvestigated, a combined meta-analysis of 17,581 cases and 20,160controls provided convincing evidence that BACH2 represents a sus-ceptibility locus for rheumatoid arthritis (McAllister et al., 2013).

3. A pre-B cell metabolic checkpoint

Normally, potentially autoreactive lymphocytes are removedby apoptosis during development and after completion of animmune response. In autoimmune diseases, however, there isabnormal lymphocyte activation and cell death, and defectiveactivation-induced cell death may be responsible for persistence ofautoreactive cells. Importantly, both cell proliferation and apopto-sis are energy-dependent processes. Recently, a phenotype-driven“reverse-genetic”, recessive ethylnitrosourea mutagenesis strat-egy was used in mice to discover genes involved in immune celldevelopment and function (Park et al., 2012). By genome scan-ning, a B cell immunodeficiency phenotype was mapped to anon-coding deletion in the Fnip1 gene, which encodes the 160-kDa protein folliculin interacting protein-1 (FNIP1). Fnip1 germline targeting led to a marked pro-B cell arrest, which cannot berescued by rapamycin treatment and is thus mTOR independent(Baba et al., 2012). Transcriptome analyses of Fnip1−/− pro-B cellsrevealed compromised expression of key genes expressed in B cells,


including VpreB1/VpreB2, �5, and Rag1/Rag2. The block is drivenby caspase activation and intrinsic cell death, and expression ofthe BCL2 anti-apoptotic transgene promotes normal numbers ofperipheral B cells in the knockout mice.


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Although the biological functions of FNIP1 and the related FNIP-amily member FNIP2 are unknown, both molecules interact witholliculin and AMP kinase, a highly conserved, master sensor andegulator of cellular metabolism. The studies suggest that FNIP1ormally acts as a molecular switch to permit pre-B cell differ-ntiation and survival in response to adequate metabolic balance,hile turning off cellular growth. FNIP1 and folliculin control BM B

ell survival and pro-B-cell differentiation. Since disruption of Fnip1esults in metabolic imbalance, and triggers apoptosis in responseo “metabolic stress”, such as pre-BCR stimulation, or nutrienteprivation, it has been proposed that this “metabolic check-oint” ensures that B cells have an adequate metabolic capacityo fuel clonal expansion and to produce Igs, while also attenuat-ng deregulated cell growth and transformation (Park et al., 2012).ecause there is evidence that dietary factors can contribute to theeoepidemiology of autoimmune diseases (Zouali, 2009), it will bemportant to determine whether this pre-B cell “metabolic check-oint”, which inhibits the maturation and survival of cells thatre “metabolically insufficient”, is functioning normally in autoim-une disease.

. Ligand-independent signaling and autoimmunity

Unlike the BCR expressed by mature B cells, the pre-BCR doesot represent a receptor for conventional antigen recognition.owever, its ability to signal despite its inability to bind con-entional antigens indicates that there is an antigen-independentre-BCR signaling (Cancro, 2009), which has been termed “tonicignaling”. The observations showing that pre-BCRs lacking con-entional ligand-binding ectodomains are able to generate signalsor B cell development led to the view that pre-BCR complexesan signal independently of engagement with extracellular ligands,nd that pre-BCR tonic signaling has an important role in directingppropriate fate decisions of developing B cells in the fetal livernd the adult BM. Consistently, lack of pre-BCR components orignaling modules leads to impaired B cell differentiation at there-B cell stage (Flemming et al., 2003). In mice, deficiency in �5esults in a substantial delay in B cell development (Kitamura et al.,992), suggesting that the pre-BCR can mediate a signal resulting

n negative selection. Such a checkpoint may also exist in humans.re-B cells from a patient with mutations in �5 expressed H-chainomplementarity-determining region 3 (CDR3) with an unusuallyigh proportion of basic amino acids, a block in B cell develop-ent that decreases peripheral B cell numbers by more than 99%,

nd agammaglobulinemia (Minegishi and Conley, 2001; Minegishit al., 1998). Consequently, the possible development of autoreac-ive B cells was not open to investigation.

SLC-deficient mice produce IgG autoantibodies and high lev-ls of antinuclear antibodies (Keenan et al., 2008). The presencef autoantibodies in sera from SLC-deficient mice indicates thatome B cells had “escaped” negative selection and, in turn, implies

potential role for the pre-BCR in censoring the developmentf autoreactive B cells. However, the molecular basis of pre-BCRignaling remains the focus of investigation. During early B cellevelopment, tight regulation of pre-BCR components ensures thatre-BCR expression is down-modulated as cells differentiate fromhe large pre-BI cell stage toward the small pre-BII cell stage, where-chains are produced (Wang et al., 2002). To prevent sustainedxpression, the pre-BCR autonomously terminates its expressionhrough BLNK-mediated induction of transcriptional silencing ofLC genes (Parker et al., 2005). Additionally, pre-BCR signaling


nduces the expression of lysosome-associated protein transmem-rane 5 (LAPTM5), which leads to the prompt downmodulation ofhe pre-BCR (Kawano et al., 2012). The fact that LAPTM5 deficiencyn pre-B cells leads to an augmented expression level of surface

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pre-BCR indicates that the pre-BCR is able to induce the promptdownmodulation of its own expression through the induction ofLAPTM5, which promotes lysosomal transport and degradation ofthe intracellular pre-BCR pool and, hence, limits the supply of pre-BCR to the cell surface (Kawano et al., 2012). Since deregulationof pre-BCR components can lead to impaired B cell developmentand autoantibody production (Keenan et al., 2008; Martin et al.,2007), it is possible that impaired expression of LAPTM5 is asso-ciated with autoimmune disease. Indeed, in a model of Sjögren’ssyndrome, Laptm5 was found to be highly expressed (Azuma et al.,2002).

5. Ligand-mediated negative selection of autoreactive Bcells

The pre-BCR does not express an Ig L-chain; but instead the pre-B SLC, composed of �5 and VpreB, associates with the Ig H-chain(Melchers, 2005 #27). Since the SLC is non-polymorphic, the pre-BCR lacks the necessary regions for binding conventional ligands.However, based on genetic models that result in either gain-of-function or loss-of-function of specific pre-BCR components anddownstream signaling proteins, regulation of pre-BCR signalingseems to be similar to that of the BCR. For example, Ig� and Ig� areboth necessary and sufficient for pre-BCR signal transduction; BCR-associated SRC-family protein tyrosine kinases are also involved inpre-BCR signaling; and co-receptors, i.e. CD19, that modulate BCRsignaling also have a role in regulating pre-BCR signaling (Rickert,2013).

While the pre-BCR cannot bind conventional ligands, severalpotential ligands whose interactions depend on the SLC have beendescribed, and there are observations to indicate that the non-Igparts of the SLC are accessible for binding to potential ligands,such as galectin-1 (GAL-1) or heparan sulfate (Bradl et al., 2003;Espeli et al., 2009) provided in the BM, possibly by stromal cells(Vettermann et al., 2008). The molecular basis of such interactionsis being deciphered.

Expression and crystallization of a soluble form of a pre-BCRconsisting of an antibody H-chain paired with the SLC revealed that“unique regions” (URs) of VpreB and �5 replace the CDR3 loop ofan antibody L-chain, and can “probe” the H-chain CDR3, potentiallyinfluencing the selection of the antibody repertoire (Bankovichet al., 2007). Whereas the �5 and VpreB components share nosequence similarity in their N- and C-terminus URs to known pro-teins, they exhibit an Ig domain-like structure, which allows the SLCto associate noncovalently into a L-chain-like structure. Followingbinding of the VpreB to the �5, this latter component undergoes aconformational change that allows the SLC to covalently interactwith the H-chain by disulphide bonding (Minegishi et al., 1999).It is the non-Ig parts of the SLC that are thought to be accessi-ble for binding to potential ligands, such as GAL-1 (Espeli et al.,2009). Recently, the first atomic view of a pre-BCR/ligand inter-action reported a minimal GAL-1-interacting region within the 45residues of the full-length �5-UR (Elantak et al., 2012).

GAL-1 is a member of a large family of mammalian lectins thatexhibit a high affinity for N-acetyl-lactosamine residues on extra-cellular glycoproteins. In general, galectins exert their biologicalactivity at the extracellular level (Rabinovich and Toscano, 2009).Once secreted, they can bind to glycoproteins on the cell surface andthe extracellular matrix, and, thereby, participate in cell-adhesionprocesses, migration, chemotaxis, cell proliferation, and apoptosis.In particular, GAL-1 is thought to play a key role in the regulation of


the immune system. It can be induced on BCR engagement, has beenassociated with BIM-1-mediated apoptosis, and may negativelyregulate B cell proliferation and BCR-mediated tyrosine phosphor-ylation. In vivo, treatment of mice with small doses of GAL-1 elicits


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otent inhibitory effects on leukocyte recruitment during inflam-ation (La et al., 2003). In an experimental model of rheumatoid

rthritis, the absence of endogenous GAL-1 led to enhanced sus-eptibility and disease severity (Iqbal et al., 2013). Conversely,xogenous GAL-1 administered parenterally or via genetically engi-eered fibroblasts ameliorates disease in experimental models ofutoimmunity (Baum et al., 2003; Liu et al., 2011; Rabinovich andoscano, 2009; Santucci et al., 2003).

Further observations indicate that GAL-1 plays a role in inducingnd/or maintaining anergic B cells. First, studies of human aner-ic B cells demonstrated that GAL-1 is significantly up-regulatedCharles et al., 2011). The second line of evidence comes fromtudies in transgenic mice expressing an Ig H-chain, that in con-unction with diverse endogenous Ig L-chains binds to laminin,

lupus nephritis-associated self-antigen. In that model, anergic cells express higher levels of mRNA and protein for GAL-1 andAL-3 relative to their naïve B cell counterparts (Clark et al., 2013).

nterestingly, global knockout of GAL-1 or GAL-3 yields subtle alter-tions in B cell fate in these transgenic mice. Specifically, GAL-3eficiency significantly increases the total number of spleen B cellsnd supports the secretion of anti-laminin autoantibodies, whereasAL-1 deficiency enhances B cell proliferation in response to a Toll-

ike receptor 4 ligand (Clark et al., 2013).Overall, these findings add to the growing body of evidence

ndicating a role for the various galectin family members, and foral-1 in particular, in the regulation of autoimmunity (Rabinovichnd Toscano, 2009). In addition to their effects on cellular immu-ity, GAL-1 and GAL-3 have been shown to modulate development,

ocalization and differentiation of B cells (Elantak et al., 2012;abinovich and Toscano, 2009; Tabrizi et al., 2009; Tsai et al., 2011).AL-1 provides a ligand for pre-B cells (Espeli et al., 2009) and plays

role in B cell anergy (Charles et al., 2011; Clark et al., 2013). It isntriguing to propose that defects in GAL-1 could lead to distortedifferentiation and/or selection of pre-B cells, impaired negativeelection of autoreactive B cells by clonal deletion and/or functionalnactivation, leading to overt loss of tolerance to self-antigens.

. Pre-B cell receptor-mediated positive selection

The biased representation of certain VH region segments in therimary B cell repertoire could reflect clonal selection at the pre-

cell stage of differentiation. This bias led to the suggestion thatre-B cells undergo positive selection directed by the presence ofurface H-chains with low-affinity to autoantigen, a mechanismhat could account for the anti-self property of the pre-immune Bell repertoire (Schwartz and Stollar, 1994). Along the same lines,t has been proposed that the pre-BCR and polyreactive receptorsre functionally equivalent, and that they share structural elementsnvolved in multispecific recognition of self-antigens (Kohler et al.,008). This functional similarity between autoreactive BCRs andhe pre-BCR could indicate that recognition of self-antigens plays aole in the positive selection of early B cells.

It has been estimated that approximately half of antibody H-hains are able to pair well with the SLC and to promote B cellevelopment (ten Boekel et al., 1997), suggesting that H-chainsould play a selective role in pro-B to pre-B cell transition. In sup-ort of this view, H-chains that pair with the SLC can give rise tore-BCRs that allow Ig�- and Ig�-domain-mediated signaling, lead-

ng to downregulation of Rag-1/2 recombinases and IL-7-dependentroliferation in large pre-B cells (Melchers, 2005). To furtherissect the mechanisms of H-chain selection, a recent study mea-


ured the fractions of in-frame rearrangements (IF fractions) of 20ifferent VH regions in genomic DNA of B cells from C5TBL/6J mice.

ndividual VH regions were found to be subject to distinctive selec-ions, and each VH had a characteristic fraction of IF rearrangements

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that was reproducible in different mice and determined at the pro-B to pre-B cell transition, implicating a role of the pre-BCR in VHselection (Meng et al., 2011). It remains unclear whether VH IF frac-tions correlate with B cell autoreactivity. Since positive selection ofautoreactive H-chains has been suggested for B-1 and fetal B cells,it is possible that autoreactive or multireactive VH regions withhigh pIs are positively selected at the pre-BCR checkpoint. Enrich-ment of such natural antibodies in the B-1 repertoire could providean innate branch of defense against commonly encountered infec-tious agents (Viau and Zouali, 2005). On the other hand, it maybe that positive charges of the H-chain alter the overall pre-BCRstructure or even interact with negative charges in the VpreB ter-minus, which, in the mouse, contains both positively and negativelycharged amino acids (Meng et al., 2011).

It has been suggested that an altered IF fraction could point toan early B cell tolerance checkpoint defect or to altered early B celldevelopment (Meng et al., 2011). Consistently, certain VH geneswere reportedly overrepresented in patients with autoimmune dis-ease (Zouali, 1995), and defects in B cell tolerance checkpoints havebeen observed in animal models and human subjects with lupusand type-1 diabetes as early as the L-chain rearrangement stage inpre-B cells (Lamoureux et al., 2007; Panigrahi et al., 2008). How-ever, it remains to be seen if the VH IF fraction for these and otherVH is different in individuals with autoimmunity.

7. A pre-B to naive B cell checkpoint defect in autoimmunedisease

Based on a modified anti-dsDNA transgenic mouse model, pre-vious studies allowed studying the site and developmental stageat which B cell regulation of self-tolerance occurs. They revealedthat in normal mice, B cells expressing an anti-DNA specificity aredeleted in the BM at a pre-B to immature B transitional stage, orjust after expression of the cell surface Ig (Chen et al., 1995). Thus,pre-B cells can be subjected to both positive (Meng et al., 2011) andnegative (Chen et al., 1995) selection for self-antigens.

In association with autoimmunity, reductions in populations ofpre-B cells have been described. For example, the NZB mouse modelof lupus develops large numbers of B cell precursors at an earlystage of embryonic development, suggesting that hyperactive B cellformation continues for the first few weeks of life (Kruger and Riley,1990). By 5–6 months of age, however, the frequency and absolutenumbers of pre-B cells are markedly reduced when compared withage-matched normal murine strains.

Additionally, B cell development in NZB mice is partiallyarrested at the pre-B cell stage. This arrest was secondary to pro-longed lifespan and greater resistance to spontaneous apoptosis(Lian et al., 2002). The increase in the frequency of pre-B cells in theBM of NZB mice was most pronounced at one month of age, and wassustained throughout the ages of the mice studied, suggesting thatthere is a block in maturation at the pre-B cell stage that leads totheir accumulation, together with an associated decrease in the fre-quencies of the subsequent stages of B cell maturation. This defectimplicates a maturational arrest of B cells in the pathogenesis ofautoimmunity in NZB mice. It suggests that some autoreactive Bcells may escape from apoptosis to continue their maturation pro-cess. Mechanisms that could account for the accumulation of the Blineage cells at the pre-B cell stage include prolonged persistenceand half-life of cells at this stage of maturation, decreased sensi-tivity to undergo apoptosis or deregulation of genes that controlB cell differentiation and maturation. It is also possible that there


is a deregulation of genes controlling B cell development at thepre-B cell stage. Importantly, RAG-2 transcripts were decreased inpre-B cells of NZB mice compared with normal mice (Lian et al.,2002), suggesting impairment of rearrangement in pre-B cells of


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ZB mice. In addition, impairment of the transcription factor PAX-, which is important for initiation of B cell development, wasbserved, supporting the view that deregulation of the cascadef gene transcription is involved in the abnormalities seen in NZBice. Studies of B cell tolerance in patients with autoimmune dis-

ases also suggest that autoimmune disease may originate fromntrinsic disorders in their developmental pathways, followed byutoreactive lymphocyte accumulation (Hikada and Zouali, 2010;ouali, 2008, 2014).

More recent studies of Sjögren’s syndrome also reveal aimilar trend. In a mouse model called B6.Aec1/2, in whichhe animals develop a Sjögren-like syndrome, with salivarynd lacrimal gland lymphocyte infiltration and xerostomia, Bell alterations were mild, but did include an early B cellheckpoint defect, with decreased numbers of BM pre-B cellsnd, correspondingly, lower frequencies of receptor editing andltered early B cell development (Meng et al., 2012). Togetherith the lupus studies summarized above, they suggest that

here is a pre-B to naive B cell checkpoint defect (Radic andouali, 1996).

As discussed above, several recent studies suggest that the pre-CR plays a role in negative selection of autoantibody-secreting Bells that express potentially pathogenic Ig H-chains. In human,

copy number loss of 22q11.2, a region harboring the VPREB1ene, has been suggested to be associated with immunologic disor-ers such as chronic autoimmune arthritis and juvenile rheumatoidrthritis-like polyarthritis (Pelkonen et al., 2002; Sullivan et al.,997). More recently, investigation of the association betweenheumatoid arthritis and the copy number variation of the VPREB1ene located at 22q11.2 disclosed that the proportion of individ-als with <2 copies of the VPREB1 gene was significantly higher

n RA patients, but that with >2 copies was significantly lowern the patients than in the control group. Remarkably, the loweropy number of VPREB1 was found to be significantly associatedith bone deformity and erosion, suggesting that <2 copies of

he VPREB1 gene may contribute to the severity and/or progres-ion of rheumatoid arthritis (Yim et al., 2011). It is possible thathe reduced dosage of the VPREB1 gene is involved in the patho-enesis of RA through altering a pre-BCR checkpoint of negativeelection.

Thus, as summarized above, even tough the pre-BCR doesot have the potential to bind conventional antigens, accu-ulating evidence indicates that pre-BCR-mediated checkpoints

re important both for negative and positive selection of self-eactivity, and that defects in these regulatory nodes mayomehow be associated with autoimmune disease. One possibil-ty is that failure to express genes important for the formationf the pre-BCR, as seen in Fnip1−/− mice, or to delete pre-Bells that were unable to generate productive rearrangements,s occurs in Bach2−/− mice, can lead to a block of B cellevelopment at the pre-B cell stage. An alternative view ishat the pre-BCR is formed normally, but altered selection ofutoreactive cells precludes purging the B cell repertoire fromutoreactivity. Further investigation is required to gain a bet-er insight into the molecular mechanisms of pre-BCR-mediatedheckpoints and to determine their relevance to autoimmune dis-ases.

isclosures

M.Z. declares no disclosures.


cknowledgments

M.Z. is supported by Inserm and University of Paris Diderot,orbone Paris Cité.

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References

Azuma, T., Takei, M., Yoshikawa, T., Nagasugi, Y., Kato, M., Otsuka, M., Shiraiwa, H.,Sugano, S., Mitamura, K., Sawada, S., Masuho, Y., Seki, N., 2002. Identification ofcandidate genes for Sjögren’s syndrome using MRL/lpr mouse model of Sjögren’ssyndrome and cDNA microarray analysis. Immunol. Lett. 81, 171–176.

Baba, M., Keller, J.R., Sun, H.W., Resch, W., Kuchen, S., Suh, H.C., Hasumi, H., Hasumi,Y., Kieffer-Kwon, K.R., Gonzalez, C.G., Hughes, R.M., Klein, M.E., Oh, H.F., Bible,P., Southon, E., Tessarollo, L., Schmidt, L.S., Linehan, W.M., Casellas, R., 2012.The folliculin-FNIP1 pathway deleted in human Birt–Hogg–Dube syndrome isrequired for murine B-cell development. Blood 120, 1254–1261.

Bankovich, A.J., Raunser, S., Juo, Z.S., Walz, T., Davis, M.M., Garcia, K.C., 2007. Struc-tural insight into pre-B cell receptor function. Science 316, 291–294.

Baum, L.G., Blackall, D.P., Arias-Magallano, S., Nanigian, D., Uh, S.Y., Browne, J.M.,Hoffmann, D., Emmanouilides, C.E., Territo, M.C., Baldwin, G.C., 2003. Ameliora-tion of graft versus host disease by galectin-1. Clin. Immunol. 109, 295–307.

Bradl, H., Wittmann, J., Milius, D., Vettermann, C., Jack, H.M., 2003. Interaction ofmurine precursor B cell receptor with stroma cells is controlled by the uniquetail of lambda 5 and stroma cell-associated heparan sulfate. J. Immunol. 171,2338–2348.

Cadera, E.J., Wan, F., Amin, R.H., Nolla, H., Lenardo, M.J., Schlissel, M.S., 2009. NF-kappaB activity marks cells engaged in receptor editing. J. Exp. Med. 206,1803–1816.

Cancro, M.P., 2009. Signalling crosstalk in B cells: managing worth and need. Nat.Rev. Immunol. 9, 657–661.

Charles, E.D., Brunetti, C., Marukian, S., Ritola, K.D., Talal, A.H., Marks, K., Jacobson,I.M., Rice, C.M., Dustin, L.B., 2011. Clonal B cells in patients with hepatitis C virus-associated mixed cryoglobulinemia contain an expanded anergic CD21low B-cell subset. Blood 117, 5425–5437.

Chen, C., Nagy, Z., Radic, M.Z., Hardy, R.R., Huszar, D., Camper, S.A., Weigert, M., 1995.The site and stage of anti-DNA B-cell deletion. Nature 373, 252–255.

Clark, A.G., Weston, M.L., Foster, M.H., 2013. Lack of galectin-1 or galectin-3 alters Bcell deletion and anergy in an autoantibody transgene model. Glycobiology 23,893–903.

Elantak, L., Espeli, M., Boned, A., Bornet, O., Bonzi, J., Gauthier, L., Feracci, M., Roche, P.,Guerlesquin, F., Schiff, C., 2012. Structural basis for galectin-1-dependent pre-Bcell receptor (pre-BCR) activation. J. Biol. Chem. 287, 44703–44713.

Espeli, M., Mancini, S.J., Breton, C., Poirier, F., Schiff, C., 2009. Impaired B-cell devel-opment at the pre-BII-cell stage in galectin-1-deficient mice due to inefficientpre-BII/stromal cell interactions. Blood 113, 5878–5886.

Flemming, A., Brummer, T., Reth, M., Jumaa, H., 2003. The adaptor protein SLP-65acts as a tumor suppressor that limits pre-B cell expansion. Nat. Immunol. 4,38–43.

Hauser, J., Verma-Gaur, J., Grundstrom, T., 2013. Broad feedback inhibition of pre-B-cell receptor signaling components. Mol. Immunol. 54, 247–253.

Hess, J., Werner, A., Wirth, T., Melchers, F., Jack, H.M., Winkler, T.H., 2001. Inductionof pre-B cell proliferation after de novo synthesis of the pre-B cell receptor. PNAS98, 1745–1750.

Hikada, M., Zouali, M., 2010. Multistoried roles for B lymphocytes in autoimmunity.Nat. Immunol. 11, 1065–1068.

Iqbal, A.J., Cooper, D., Vugler, A., Gittens, B.R., Moore, A., Perretti, M., 2013. Endoge-nous galectin-1 exerts tonic inhibition on experimental arthritis. J. Immunol.191, 171–177.

Kawano, Y., Ouchida, R., Wang, J.Y., Yoshikawa, S., Yamamoto, M., Kitamura, D.,Karasuyama, H., 2012. A novel mechanism for the autonomous terminationof pre-B cell receptor expression via induction of lysosome-associated proteintransmembrane 5. Mol. Cell. Biol. 32, 4462–4471.

Keenan, R.A., De Riva, A., Corleis, B., Hepburn, L., Licence, S., Winkler, T.H., Martens-son, I.L., 2008. Censoring of autoreactive B cell development by the pre-B cellreceptor. Science 321, 696–699.

Kitamura, D., Kudo, A., Schaal, S., Muller, W., Melchers, F., Rajewsky, K.,1992. A critical role of lambda 5 protein in B cell development. Cell 69,823–831.

Kohler, F., Hug, E., Eschbach, C., Meixlsperger, S., Hobeika, E., Kofer, J., Wardemann,H., Jumaa, H., 2008. Autoreactive B cell receptors mimic autonomous pre-Bcell receptor signaling and induce proliferation of early B cells. Immunity 29,912–921.

Kruger, M.G., Riley, R.L., 1990. The age-dependent loss of bone marrow B cell pre-cursors in autoimmune NZ mice results from decreased mitotic activity, but notfrom inherent stromal cell defects. J. Immunol. 144, 103–110.

La, M., Cao, T.V., Cerchiaro, G., Chilton, K., Hirabayashi, J., Kasai, K., Oliani, S.M.,Chernajovsky, Y., Perretti, M., 2003. A novel biological activity for galectin-1:inhibition of leukocyte-endothelial cell interactions in experimental inflamma-tion. Am. J. Pathol. 163, 1505–1515.

Lamoureux, J.L., Watson, L.C., Cherrier, M., Skog, P., Nemazee, D., Feeney, A.J.,2007. Reduced receptor editing in lupus-prone MRL/lpr mice. J. Exp. Med. 204,2853–2864.

Lian, Z.X., Kita, H., Okada, T., Hsu, T., Shultz, L.D., Dorshkind, K., Ansari, A.A., Ikehara,S., Naiki, M., Gershwin, M.E., 2002. Increased frequency of pre-pro B cells in thebone marrow of New Zealand Black (NZB) mice: implications for a developmen-tal block in B cell differentiation. Dev. Immunol. 9, 35–45.

Liu, S.D., Lee, S., La Cava, A., Motran, C.C., Hahn, B.H., Miceli, M.C., 2011. Galectin-1-


induced down-regulation of T lymphocyte activation protects (NZB × NZW) F1mice from lupus-like disease. Lupus 20, 473–484.

Lu, R., Medina, K.L., Lancki, D.W., Singh, H., 2003. IRF-4,8 orchestrate the pre-B-to-Btransition in lymphocyte development. Genes Dev. 17, 1703–1708.


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a, S., Turetsky, A., Trinh, L., Lu, R., 2006. IFN regulatory factor 4 and 8 promote Iglight chain kappa locus activation in pre-B cell development. J. Immunol. 177,7898–7904.

artin, D.A., Lu, L., Cascalho, M., Wu, G.E., 2007. Maintenance of surrogate lightchain expression induces developmental delay in early B cell compartment. J.Immunol. 179, 4996–5005.

cAllister, K., Yarwood, A., Bowes, J., Orozco, G., Viatte, S., Diogo, D., Hocking, L.J.,Steer, S., Wordsworth, P., Wilson, A.G., Morgan, A.W., Kremer, J., Pappas, D.,Gregersen, P., Klareskog, L., Plenge, R., Barton, A., Greenberg, J., Worthington,J., Eyre, S., 2013. Meta-analysis identifies BACH2 and RAD51B as rheumatoidarthritis susceptibility loci. Arthritis Rheum. 65, 3058–3062.

elchers, F., 2005. The pre-B-cell receptor: selector of fitting immunoglobulin heavychains for the B-cell repertoire. Nat. Rev. Immunol. 5, 578–584.

eng, W., Li, Y., Xue, E., Satoh, M., Peck, A.B., Cohen, P.L., Eisenberg, R.A., Luning Prak,E.T., 2012. B-cell tolerance defects in the B6.Aec1/2 mouse model of Sjögren’ssyndrome. J. Clin. Immunol. 32, 551–564.

eng, W., Yunk, L., Wang, L.S., Maganty, A., Xue, E., Cohen, P.L., Eisenberg, R.A.,Weigert, M.G., Mancini, S.J., Prak, E.T., 2011. Selection of individual VH genesoccurs at the pro-B to pre-B cell transition. J. Immunol. 187, 1835–1844.

inegishi, Y., Conley, M.E., 2001. Negative selection at the pre-BCR checkpointelicited by human mu heavy chains with unusual CDR3 regions. Immunity 14,631–641.

inegishi, Y., Coustan-Smith, E., Wang, Y.H., Cooper, M.D., Campana, D., Conley, M.E.,1998. Mutations in the human lambda5/14.1 gene result in B cell deficiency andagammaglobulinemia. J. Exp. Med. 187, 71–77.

inegishi, Y., Hendershot, L.M., Conley, M.E., 1999. Novel mechanisms control thefolding and assembly of lambda5/14.1 and VpreB to produce an intact surrogatelight chain. PNAS 96, 3041–3046.

ahar, R., Ramezani-Rad, P., Mossner, M., Duy, C., Cerchietti, L., Geng, H., Dovat, S.,Jumaa, H., Ye, B.H., Melnick, A., Muschen, M., 2011. Pre-B cell receptor-mediatedactivation of BCL6 induces pre-B cell quiescence through transcriptional repres-sion of MYC. Blood 118, 4174–4178.

smond, D.G., 1991. Proliferation kinetics and the lifespan of B cells in central andperipheral lymphoid organs. Curr. Opin. Immunol. 3, 179–185.

anigrahi, A.K., Goodman, N.G., Eisenberg, R.A., Rickels, M.R., Naji, A., Luning Prak,E.T., 2008. RS rearrangement frequency as a marker of receptor editing in lupusand type 1 diabetes. J. Exp. Med. 205, 2985–2994.

ark, H., Staehling, K., Tsang, M., Appleby, M.W., Brunkow, M.E., Margineantu,D., Hockenbery, D.M., Habib, T., Liggitt, H.D., Carlson, G., Iritani, B.M., 2012.Disruption of Fnip1 reveals a metabolic checkpoint controlling B lymphocytedevelopment. Immunity 36, 769–781.

arker, M.J., Licence, S., Erlandsson, L., Galler, G.R., Chakalova, L., Osborne, C.S., Mor-gan, G., Fraser, P., Jumaa, H., Winkler, T.H., Skok, J., Martensson, I.L., 2005. Thepre-B-cell receptor induces silencing of VpreB and lambda5 transcription. EMBOJ. 24, 3895–3905.

athak, S., Ma, S., Shukla, V., Lu, R., 2013. A role for IRF8 in B cell anergy. J. Immunol.191, 6222–6230.

elkonen, P., Lahdenne, P., Lantto, R., Honkanen, V., 2002. Chronic arthritisassociated with chromosome deletion 22q11.2 syndrome. J. Rheumatol. 29,2648–2650.


abinovich, G.A., Toscano, M.A., 2009. Turning ‘sweet’ on immunity: galectin–glycaninteractions in immune tolerance and inflammation. Nat. Rev. Immunol. 9,338–352.

adic, M.Z., Zouali, M., 1996. Receptor editing, immune diversification, and self-tolerance. Immunity 5, 505–511.

PRESSlogy xxx (2014) xxx–xxx

Rickert, R.C., 2013. New insights into pre-BCR and BCR signalling with relevance toB cell malignancies. Nat. Rev. Immunol. 13, 578–591.

Sakaguchi, N., Melchers, F., 1986. Lambda 5, a new light-chain-related locus selec-tively expressed in pre-B lymphocytes. Nature 324, 579–582.

Santucci, L., Fiorucci, S., Rubinstein, N., Mencarelli, A., Palazzetti, B., Federici, B.,Rabinovich, G.A., Morelli, A., 2003. Galectin-1 suppresses experimental colitisin mice. Gastroenterology 124, 1381–1394.

Schwartz, R.S., Stollar, B.D., 1994. Heavy-chain directed B-cell maturation: contin-uous clonal selection beginning at the pre-B cell stage. Immunol. Today 15,27–32.

Sullivan, K.E., McDonald-McGinn, D.M., Driscoll, D.A., Zmijewski, C.M., Ellabban, A.S.,Reed, L., Emanuel, B.S., Zackai, E.H., Athreya, B.H., Keenan, G., 1997. Juvenilerheumatoid arthritis-like polyarthritis in chromosome 22q11.2 deletion syn-drome (DiGeorge anomalad/velocardiofacial syndrome/conotruncal anomalyface syndrome). Arthritis Rheum. 40, 430–436.

Swaminathan, S., Huang, C., Geng, H., Chen, Z., Harvey, R., Kang, H., Ng, C., Titz,B., Hurtz, C., Sadiyah, M.F., Nowak, D., Thoennissen, G.B., Rand, V., Grae-ber, T.G., Koeffler, H.P., Carroll, W.L., Willman, C.L., Hall, A.G., Igarashi, K.,Melnick, A., Muschen, M., 2013. BACH2 mediates negative selection and p53-dependent tumor suppression at the pre-B cell receptor checkpoint. Nat. Med.19, 1014–1022.

Tabrizi, S.J., Niiro, H., Masui, M., Yoshimoto, G., Iino, T., Kikushige, Y., Wakasaki,T., Baba, E., Shimoda, S., Miyamoto, T., Hara, T., Akashi, K., 2009. T cellleukemia/lymphoma 1 and galectin-1 regulate survival/cell death pathways inhuman naive and IgM+ memory B cells through altering balances in Bcl-2 familyproteins. J. Immunol. 182, 1490–1499.

ten Boekel, E., Melchers, F., Rolink, A.G., 1997. Changes in the V(H) gene repertoireof developing precursor B lymphocytes in mouse bone marrow mediated by thepre-B cell receptor. Immunity 7, 357–368.

Tsai, C.M., Guan, C.H., Hsieh, H.W., Hsu, T.L., Tu, Z., Wu, K.J., Lin, C.H., Lin, K.I., 2011.Galectin-1 and galectin-8 have redundant roles in promoting plasma cell for-mation. J. Immunol. 187, 1643–1652.

van Loo, P.F., Dingjan, G.M., Maas, A., Hendriks, R.W., 2007. Surrogate-light-chainsilencing is not critical for the limitation of pre-B cell expansion but is for thetermination of constitutive signaling. Immunity 27, 468–480.

Vettermann, C., Herrmann, K., Albert, C., Roth, E., Bosl, M.R., Jack, H.M., 2008. Aunique role for the lambda5 nonimmunoglobulin tail in early B lymphocytedevelopment. J. Immunol. 181, 3232–3242.

Viau, M., Zouali, M., 2005. B-lymphocytes, innate immunity, and autoimmunity. Clin.Immunol. 114, 17–26.

Wang, Y.H., Stephan, R.P., Scheffold, A., Kunkel, D., Karasuyama, H., Radbruch, A.,Cooper, M.D., 2002. Differential surrogate light chain expression governs B-celldifferentiation. Blood 99, 2459–2467.

Yim, S.H., Chung, Y.J., Jin, E.H., Shim, S.C., Kim, J.Y., Kim, Y.S., Hu, H.J., Shin, S.H.,Pae, H.O., Zouali, M., Chung, H.T., 2011. The potential role of VPREB1 gene copynumber variation in susceptibility to rheumatoid arthritis. Mol. Immunol. 48,1338–1343.

Zouali, M., 1995. Human pathogenic autoantibodies and their escape from deletion.Ann. N.Y. Acad. Sci. 764, 436–439.

Zouali, M., 2008. Receptor editing and receptor revision in rheumatic autoimmune


diseases. Trends Immunol. 29, 103–109.Zouali, M., 2014. Tweaking the B lymphocyte compartment in autoimmune diseases.

Nat. Immunol., in press.Zouali, M. (Ed.), 2009. The Epigenetics of Autoimmune Diseases. Wiley-Blackwell

(an imprint of John Wiley & Sons Ltd) (April 3 2009).
































































































































































































































































































































































































































































































































































































































































































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