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Background: The role of B cells in antitumor immunity remains controversial, with studies suggesting the protumor and antitumor activity. This controversy may be due to the heterogeneity in B cell populations, as the balance among the subtypes may impact tumor progression. The immunosuppressive regulatory B cells (Breg) release interleukin 10 (IL-10) but only represent a minor population. Additionally, tumor-specific antibodies (Abs) also exhibit antitumor and protumor functions dependent on the Ab isotype. Transcription factor c-Maf has been suggested to contribute to the regulation of IL-10 in Breg, but the role of B cell c-Maf signaling in antitumor immunity and regulating Ab responses remains unknown., Methods: Conditional B cell c-Maf knockout (KO) and control mice were used to establish a KPC pancreatic cancer model and B16.F10 melanoma model. Tumor progression was evaluated. B cell and T cell phenotypes were determined by flow cytometry, mass cytometry, and cytokine/chemokine profiling. Differentially expressed genes in B cells were examined by using RNA sequencing (RNA-seq). Peripheral blood samples were collected from healthy donors and patients with melanoma for B cell phenotyping., Results: Compared with B cells from the spleen and lymph nodes (LN), B cells in the pancreas exhibited significantly less follicular phenotype and higher IL-10 production in naïve mice. c-Maf deficiency resulted in a significant reduction of CD9 + IL-10-producing Breg in the pancreas. Pancreatic ductal adenocarcinoma (PDAC) progression resulted in the accumulation of circulating B cells with the follicular phenotype and less IL-10 production in the pancreas. Notably, B cell c-Maf deficiency delayed PDAC tumor progression and resulted in proinflammatory B cells. Further, tumor volume reduction and increased effective T cells in the tumor-draining LN were observed in B cell c-Maf KO mice in the B16.F10 melanoma model. RNA-seq analysis of isolated B cells revealed that B cell c-Maf signaling modulates immunoglobulin-associated genes and tumor-specific Ab production. We furthermore demonstrated c-Maf-positive B cell subsets and an increase of IL-10-producing B cells after incubation with IL-4 and CD40L in the peripheral blood of patients with melanoma., Conclusion: Our study highlights that B cell c-Maf signaling drives tumor progression through the modulation of Breg, inflammatory responses, and tumor-specific Ab responses., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

The SAGA complex is an evolutionarily conserved histone acetyltransferase complex and transcription coactivator essential for development and disease. Dysregulation of SAGA is implicated in various human diseases, including cancer. In this issue of Genes & Development, Chen et al. (doi:10.1101/gad.351789.124) uncover a critical role for SAGA in multiple myeloma wherein SAGA's ADA2B component is required for the expression of mTORC1 pathway genes and targets of the MYC, E2F, and MAF (musculoaponeurotic fibrosarcoma) transcription factors. SAGA cooperates with MYC and MAF to sustain oncogenic gene expression programs vital for multiple myeloma survival and thus may serve as a therapeutic target for future cancer therapies., (© 2024 Wang et al.; Published by Cold Spring Harbor Laboratory Press.)

Precise regulation of B cell differentiation is essential for an effective adaptive immune response. Here, we show that B cell development in mice with B cell-specific Maf deletion is unaffected, but marginal zone B cells, germinal centre B cells, and plasmablasts are significantly more frequent in the spleen of naive Maf-deficient mice compared to wild type controls. In the context of a T cell-dependent immunization, Maf deletion causes increased proliferation of germinal centre B cells and extrafollicular plasmablasts. This is accompanied by higher production of antigen-specific IgG1 antibodies with minimal modification of early memory B cells, but a reduction in plasma cell numbers. Single-cell RNA sequencing shows upregulation of genes associated with DNA replication and cell cycle progression, confirming the role of Maf in cell proliferation. Subsequent pathway analysis reveals that Maf influences cellular metabolism, transporter activity, and mitochondrial proteins, which have been implicated in controlling the germinal centre reaction. In summary, our findings demonstrate that Maf acts intrinsically in B cells as a negative regulator of late B cell differentiation, plasmablast proliferation and germinal centre B cell formation., (© 2024. The Author(s).)

Objectives: Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disease, of which the pathogens is remains obscure. Viral infection, particularly Epstein Barr viru (EBV) infection, has been considered a common pathogenic factor. This study suggests that c-Maf may be an important target in T cell differentiation during SLE progression, providing a potentially new perspective on the role of viral infection in the pathogenesis of autoimmune diseases., Methods: Cytokines of EBV-infected SLE patients were measured by ELISA and assessed in conjunction with their clinical data. IFN-α, c-Maf, and the differentiation of Th17/Treg cells in SLE patients and MRL/LPR mice were analyzed using FCM, WB, RT-PCR, etc. Following the infection of cells and mice with EBV or viral mimic poly (dA:dT), the changes of the aforementioned indicators were investigated. The relationship among IFN-α, STAT3, c-Maf and Th17 cells was determined by si-RNA technique., Results: Many SLE patients are found to be complicated by viral infections; Further, studies have demonstrated that viral infection, especially EBV, is involved in SLE development. This study showed that viral infections might promote IFN-α secretion, inhibit c-Maf expression by activating STAT3, increase Th17 cell differentiation, and lead to the immune imbalance of Th17/Treg cells, thus playing a role in the onset and progression of SLE., Conclusion: This study demonstrates that EBV infections may contribute to SLE development by activating STAT3 through IFN-α, inhibiting c-Maf, and causing Th17/Treg immune imbalance. Our work provided a new insight into the pathogenesis and treatment of SLE., Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The MAF gene encodes a transcription factor in which pathogenic variants have been associated with both isolated and syndromic congenital cataracts. We aim to review the MAF variants in the C-terminal DNA-binding domain associated with non-syndromic congenital cataracts and describe a patient with a novel, disease-causing de novo missense variant. Published reports of C-terminal MAF variants and their associated congenital cataracts and ophthalmic findings were reviewed. The patient we present and his biological parents had genetic testing via a targeted gene panel followed by trio-based whole exome sequencing. A 4-year-old patient with a history of bilateral nuclear and cortical cataracts was found to have a novel, likely pathogenic de novo variant in MAF , NM_005360.5:c.922A>G (p.Lys308Glu). No syndromic findings or anterior segment abnormalities were identified. We report the novel missense variant, c.922A>G (p.Lys308Glu), in the C-terminal DNA-binding domain of MAF classified as likely pathogenic and associated with non-syndromic bilateral congenital cataracts.

Intestinal immune responses to microbes are controlled by the cytokine IL-10 to avoid immune pathology. Here, we use single-cell RNA sequencing of colon lamina propria leukocytes (LPLs) along with RNA-seq and ATAC-seq of purified CD4 + T cells to show that the transcription factors Blimp-1 (encoded by Prdm1) and c-Maf co-dominantly regulate Il10 while negatively regulating proinflammatory cytokines in effector T cells. Double-deficient Prdm1 fl/fl Maf fl/fl Cd4 Cre mice infected with Helicobacter hepaticus developed severe colitis with an increase in T H 1/NK/ILC1 effector genes in LPLs, while Prdm1 fl/fl Cd4 Cre and Maf fl/fl Cd4 Cre mice exhibited moderate pathology and a less-marked type 1 effector response. LPLs from infected Maf fl/fl Cd4 Cre mice had increased type 17 responses with increased Il17a and Il22 expression and an increase in granulocytes and myeloid cell numbers, resulting in increased T cell-myeloid-neutrophil interactions. Genes over-expressed in human inflammatory bowel disease showed differential expression in LPLs from infected mice in the absence of Prdm1 or Maf, revealing potential mechanisms of human disease., (© 2024. The Author(s).)

MAF amplification increases the risk of breast cancer (BCa) metastasis through mechanisms that are still poorly understood yet have important clinical implications. Oestrogen-receptor-positive (ER + ) BCa requires oestrogen for both growth and metastasis, albeit by ill-known mechanisms. Here we integrate proteomics, transcriptomics, epigenomics, chromatin accessibility and functional assays from human and syngeneic mouse BCa models to show that MAF directly interacts with oestrogen receptor alpha (ERα), thereby promoting a unique chromatin landscape that favours metastatic spread. We identify metastasis-promoting genes that are de novo licensed following oestrogen exposure in a MAF-dependent manner. The histone demethylase KDM1A is key to the epigenomic remodelling that facilitates the expression of the pro-metastatic MAF/oestrogen-driven gene expression program, and loss of KDM1A activity prevents this metastasis. We have thus determined that the molecular basis underlying MAF/oestrogen-mediated metastasis requires genetic, epigenetic and hormone signals from the systemic environment, which influence the ability of BCa cells to metastasize., (© 2023. The Author(s).)

The primary function of the small intestine (SI) is to absorb nutrients to maintain whole-body energy homeostasis. Enterocytes are the major epithelial cell type facilitating nutrient sensing and uptake. However, the molecular regulators governing enterocytes have remained undefined. Here, we identify c-Maf as an enterocyte-specific transcription factor within the SI epithelium. c-Maf expression was determined by opposing Noggin/BMP signals and overlapped with the zonated enrichment of nutrient transporters in the mid-villus region. Functionally, enterocytes required c-Maf to appropriately differentiate along the villus axis. Specifically, gene programs controlling carbohydrate and protein absorption were c-Maf-dependent. Consequently, epithelial cell-specific c-Maf deletion resulted in impaired enterocyte maturation and nutrient uptake, including defects in the adaptation to different nutrient availability. Concomitantly, intraepithelial lymphocytes were less abundant, while commensal epithelial cell-attaching SFB overgrew in a c-Maf-deficient environment, highlighting the close interdependence between the intestinal epithelium, immune system, and microbiota. Collectively, our data identified c-Maf as a key regulator of SI enterocyte differentiation and function, essential for nutrient, immune, and microbial homeostasis., (© 2022 Cosovanu et al.)

Pathogenic variants in the v-maf avian musculoaponeurotic fibrosarcoma oncogene homologue (MAF) encoding a transcription factor (from a unique subclass of basic leucine zipper transcription factors) are associated with isolated congenital cataracts (CCs) and Aymé-Gripp syndrome (AYGRPS). We collected detailed disease histories from, and performed comprehensive ophthalmic and systemic examinations in 269 patients with CCs; we then performed whole-exome sequencing. Pathogenicity assessments were evaluated using multiple predictive tools. The clinical validities of the reported gene-disease relationships for MAF genes (MAF-CCs and MAF-AYGRPS) were assessed using the ClinGen gene curation framework. We identified two novel (c.173C>A, p.Thr58Asn and c.947T>C, p. Leu316Pro) variants and one known (c.173C>T, p.Thr58Ile) MAF missense variant in three patients. We described novel phenotypes including cleft palate, macular hypoplasia, and retinal neovascularization in the peripheral avascular area and analyzed the genotype-phenotype correlations. We demonstrated associations of variants in the MAF C-terminal DNA-binding domain with CCs and associations of variants in the N-terminal transactivation domain of MAF with AYGRPS. We thus expand the genotypic and phenotypic spectrum of the MAF gene. The ClinGen gene curation framework results suggested that variants in different domains of MAF are associated with different diseases., (© 2022 Wiley Periodicals LLC.)

Despite recent advances in therapeutic treatments, multiple myeloma (MM) remains an incurable malignancy. Epigenetic factors contribute to the initiation, progression, relapse, and clonal heterogeneity in MM, but our knowledge on epigenetic mechanisms underlying MM development is far from complete. The SAGA complex serves as a coactivator in transcription and catalyzes acetylation and deubiquitylation. Analyses of data sets in the Cancer Dependency Map Project revealed that many SAGA components are selective dependencies in MM. To define SAGA-specific functions, we focused on ADA2B, the only subunit in the lysine acetyltransferase (KAT) module that specifically functions in SAGA. Integration of RNA sequencing (RNA-seq), assay for transposase-accessible chromatin with sequencing (ATAC-seq), and cleavage under targets and release using nuclease assay (CUT&RUN) results identified pathways directly regulated by ADA2B including MTORC1 signaling and oncogenic programs driven by MYC, E2F, and MM-specific MAF. We discovered that ADA2B is recruited to MAF and MYC gene targets, and that MAF shares a majority of its targets with MYC in MM cells. Furthermore, we found that the SANT domain of ADA2B is required for interaction with both GCN5 and PCAF acetyltransferases, incorporation into SAGA, and ADA2B protein stability. Our findings uncover previously unknown SAGA KAT module-dependent mechanisms controlling MM cell growth, revealing a vulnerability that might be exploited for future development of MM therapy., (© 2024 Chen et al.; Published by Cold Spring Harbor Laboratory Press.)

Cellular metabolism has been proposed to govern distinct γδ T cell effector functions, but the underlying molecular mechanisms remain unclear. We show that interleukin-17 (IL-17)-producing γδ T (γδT17) and interferon-γ (IFN-γ)-producing γδ T (γδT1) cells have differential metabolic requirements and that the rate-limiting enzyme isocitrate dehydrogenase 2 (IDH2) acts as a metabolic checkpoint for their effector functions. Intriguingly, the transcription factor c-Maf regulates γδT17 effector function through direct regulation of IDH2 promoter activity. Moreover, mTORC2 affects the expression of c-Maf and IDH2 and subsequent IL-17 production in γδ T cells. Deletion of c-Maf in γδ T cells reduces metastatic lung cancer development, suggesting c-Maf as a potential target for cancer immune therapy. We show that c-Maf also controls IL-17 production in human γδ T cells from peripheral blood and in oral cancers. These results demonstrate a critical role of the transcription factor c-Maf in regulating γδT17 effector function through IDH2-mediated metabolic reprogramming.

In this issue of Cell Stem Cell, Gómez-Salinero et al. (2022) identify c-Maf as a driver for murine liver sinusoidal endothelial cell (LSEC) fate and function during liver development, homeostasis, and repair. Similarly, c-Maf defines human LSECs, and its overexpression specializes generic HUVECs into functional induced-LSECs, potentiating regenerative therapeutics., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background and Objectives: Multiple sclerosis (MS) is an inflammatory demyelinating disease of the CNS. CD8 + T cells are prominently found at inflammatory sites. Recent advances in understanding checkpoint molecules, including programmed cell death 1 (PD-1), expressed on CD8 + T cells, highlight the immune regulatory roles of this T-cell subset; however, the role of CD8 + T cells in MS is unclear. Thus, we aimed to reveal the characteristics of PD-1-expressed (PD-1 + ) CD8 + T cells in MS., Methods: We performed a cohort, case-control study for phenotyping analysis of PD-1 + CD8 + T cells in disease remission and flare states using CSF and peripheral blood samples of 45 patients with MS or clinically isolated syndrome and 12 healthy subjects. We further analyzed the transcriptome of sorted PD-1 + CD8 + T cells obtained from interferon (IFN)-β-treated patients and validated their regulatory machinery using in vitro cell culture assays with lentiviral gene transfer., Results: In the disease remission state, PD-1 + CD8 + T cells were decreased in the peripheral blood of patients with MS and resolved in patients treated with IFN-β treatment who showed immune regulatory cytokine interleukin (IL)-10 expression. In the disease flare state, we found that PD-1 + CD8 + T cells were enriched in the CSF, which predicted a good response to subsequent IV steroid therapy. Transcriptome analysis of sorted PD-1 + CD8 + T cells revealed the transcription factor c-Maf as a potential major regulator of the gene module, including multiple coinhibitory molecules. Furthermore, c-Maf expressed in CD8 + T cells induced PD-1 expression and production of IL-10 as well as suppressed alloactivated CD4 + T-cell survival., Discussion: This study uncovered a favorable role of PD-1 + CD8 + T cells against MS and demonstrated that c-Maf-driven IL-10 is an immune regulatory machinery., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

Topoisomerase (TOP) inhibitors were commonly used as chemotherapeutic agents in the treatment of cancers. In our present study, we found that etoposide (ETO), a topoisomerase 2 (TOP2) inhibitor, upregulated the production of Interleukin 10 (IL-10) in lipopolysaccharide (LPS)-stimulated macrophages. Besides, other TOP2 inhibitors including doxorubicin hydrochloride (DOX) and teniposide (TEN) were also able to augment IL-10 production. Meanwhile, the expression levels of pro-inflammatory factors, for example IL-6 and TNF-α, were also decreased accordingly by the treatment of the TOP2 inhibitors. Of note, ETO facilitated IL-10 secretion, which might be regulated by transcription factor Maf via PI3K/AKT pathway, as pharmaceutic blockage of kinase PI3K or AKT attenuated ETO-induced Maf and IL-10 expression. Further, in LPS-induced mice sepsis model, the enhanced generation of IL-10 was observed in ETO-treated mice, whereas pro-inflammatory cytokines were decreased, which significantly reduced the mortality of mice from LPS-induced lethal cytokine storm. Taken together, these results indicated that ETO may exhibit an anti-inflammatory role by upregulating the alteration of transcription factor Maf and promoting subsequential IL-10 secretion via PI3K/Akt pathway in LPS-induced macrophages. Therefore, ETO may serve as a potential anti-inflammatory agent and employed to severe pro-inflammatory diseases including COVID-19., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Testis differentiation is initiated when Sry in pre-Sertoli cells directs the gonad toward a male-specific fate. Sertoli cells are essential for testis development, but cell types within the interstitial compartment, such as immune and endothelial cells, are also critical for organ formation. Our previous work implicated macrophages in fetal testis morphogenesis, but little is known about genes underlying immune cell development during organogenesis. Here, we examine the role of the immune-associated genes Mafb and Maf in mouse fetal gonad development, and we demonstrate that deletion of these genes leads to aberrant hematopoiesis manifested by supernumerary gonadal monocytes. Mafb; Maf double knockout embryos underwent initial gonadal sex determination normally, but exhibited testicular hypervascularization, testis cord formation defects, Leydig cell deficit, and a reduced number of germ cells. In general, Mafb and Maf alone were dispensable for gonad development; however, when both genes were deleted, we observed significant defects in testicular morphogenesis, indicating that Mafb and Maf work redundantly during testis differentiation. These results demonstrate previously unappreciated roles for Mafb and Maf in immune and vascular development and highlight the importance of interstitial cells in gonadal differentiation., (© The Author(s) 2021. Published by Oxford University Press on behalf of Society for the Study of Reproduction. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Immune response control is critical as excessive cytokine production can be detrimental and damage the host. Interleukin-10 (Il-10), an anti-inflammatory cytokine produced primarily by macrophages, is a key regulator that counteracts and controls excessive inflammatory response. Il-10 expression is regulated through the transcription factor c-Maf. Another regulator of Il-10 production is p35, an activator of the cyclin-dependent kinase 5 (Cdk5), which decreases Il-10 production in macrophages, thus increasing inflammation. However, Cdk5 regulation of c-Maf and the involvement of Il-10 production in macrophages has not yet been investigated. We used in vitro primary bone marrow-derived macrophages (BMDMs) lacking Cdk5 , stimulated them with lipopolysaccharid (LPS) and observed increased levels of c-Maf and Il-10. In an in vivo mouse model of LPS-induced endotoxemia, mice lacking Cdk5 in macrophages showed increased levels of c-Maf and elevated levels of Il-10 in lungs as well as in plasma, resulting in ameliorated survival. Taken together, we identified Cdk5 as a potential novel regulator of Il-10 production through c-Maf in macrophages under inflammatory conditions. Our results suggest that inhibition of Cdk5 enhances the c-Maf-Il-10 axis and thus potentiates improvement of anti-inflammatory therapy.

Age is a major risk factor for cataract (ARC). However, the influence of aging on the lens transcriptome is under studied. Lens epithelial (LEC) and fiber cells (LFC) were isolated from young (3 month old) and aged (24 month old) C57BL/6J mice, and the transcriptome elucidated via RNAseq. EdgeR estimated differential gene expression in pairwise contrasts, and Advaita's Ipathway guide and custom R scripts were used to evaluate the potential biological significance of differentially expressed genes (DEGs). This analysis revealed age-dependent decreases in lens differentiation marker expression in both LECs and LFCs, with gamma crystallin transcripts downregulating nearly 50 fold in aged LFCs. The expression of the transcription factors Hsf4 and Maf, which are known to activate lens fiber cell preferred genes, are downregulated, while FoxE3, which represses gamma crystallin expression, is upregulated in aged fibers. Aged LECs upregulate genes controlling the immune response, complement pathways, and cellular stress responses, including glutathione peroxidase 3 (Gpx3). Aged LFCs exhibit broad changes in the expression of genes regulating cell communication, and upregulate genes involved in antigen processing/presentation and cholesterol metabolism, while changes in the expression of mitochondrial respiratory chain genes are consistent with mitochondrial stress, including upregulation of NDufa4l2, which encodes an alternate electron transport chain protein. However, age did not profoundly affect the response of LECs to injury as both young and aged LECs upregulate inflammatory gene signatures at 24 h post injury to similar extents. These RNAseq profiles provide a rich data set that can be mined to understand the genetic regulation of lens aging and how this impinges on the pathophysiology of age related cataract., (Copyright © 2021. Published by Elsevier Ltd.)

MAF is a transcription factor that may act either as a tumor suppressor or as an oncogene, depending on cell type. We have shown previously that the overexpressed miR-1290 influences MAF protein levels in LSCC (laryngeal squamous cell carcinoma) cell lines. In this study, we shed further light on the interaction between miR-1290 and MAF , as well as on cellular MAF protein localization in LSCC. We confirmed the direct interaction between miR-1290 and MAF 3'UTR by a dual-luciferase reporter assay. In addition, we used immunohistochemistry staining to analyze MAF protein distribution and observed loss of MAF nuclear expression in 58% LSCC samples, of which 10% showed complete absence of MAF, compared to nuclear and cytoplasmatic expression in 100% normal mucosa. Using TCGA data, bisulfite pyrosequencing and CNV analysis, we excluded the possibility that loss-of-function mutations, promoter region DNA methylation or CNV are responsible for MAF loss in LSCC. Finally, we identified genes involved in the regulation of apoptosis harboring the MAF binding motif in their promoter region by applied FIMO and DAVID GO analysis. Our results highlight the role of miR-1290 in suppressing MAF expression in LSCC. Furthermore, MAF loss or mislocalization in FFPE LSCC tumor samples might suggest that MAF acts as a LSCC tumor suppressor by regulating apoptosis.

Background: The oncogenic transcript factor c-Maf is stabilized by the deubiquitinase Otub1 and promotes myeloma cell proliferation and confers to chemoresistance. Inhibition of the Otub1/c-Maf axis is a promising therapeutic target, but there are no inhibitors reported on this specific axis., Methods: A luciferase assay was applied to screen potential inhibitors of Otub1/c-Maf. Annexin V staining/flow cytometry was applied to evaluate cell apoptosis. Immunoprecipitation was applied to examine protein ubiquitination and interaction. Xenograft models in nude mice were used to evaluate anti-myeloma activity of AVT., Results: Acevaltrate (AVT), isolated from Valeriana glechomifolia, was identified based on a bioactive screen against the Otub1/c-Maf/luciferase system. AVT disrupts the interaction of Otub1/c-Maf thus inhibiting Otub1 activity and leading to c-Maf polyubiquitination and subsequent degradation in proteasomes. Consistently, AVT inhibits c-Maf transcriptional activity and downregulates the expression of its target genes key for myeloma growth and survival. Moreover, AVT displays potent anti-myeloma activity by triggering myeloma cell apoptosis in vitro and impairing myeloma xenograft growth in vivo but presents no marked toxicity., Conclusions: The natural product AVT inhibits the Otub1/c-Maf axis and displays potent anti-myeloma activity. Given its great safety and efficacy, AVT could be further developed for MM treatment. Video Abstract.

Despite extensive mapping of long noncoding RNAs in immune cells, their function in vivo remains poorly understood. In this study, we identify over 100 long noncoding RNAs that are differentially expressed within 24 h of Th1 cell activation. Among those, we show that suppression of Malat1 is a hallmark of CD4 + T cell activation, but its complete deletion results in more potent immune responses to infection. This is because Malat1 -/- Th1 and Th2 cells express lower levels of the immunosuppressive cytokine IL-10. In vivo, the reduced CD4 + T cell IL-10 expression in Malat1 -/- mice underpins enhanced immunity and pathogen clearance in experimental visceral leishmaniasis ( Leishmania donovani ) but more severe disease in a model of malaria ( Plasmodium chabaudi chabaudi AS). Mechanistically, Malat1 regulates IL-10 through enhancing expression of Maf, a key transcriptional regulator of IL-10 Maf expression correlates with Malat1 in single Ag-specific Th cells from P. chabaudi chabaudi AS-infected mice and is downregulated in Malat1 -/- Th1 and Th2 cells. The Malat1 RNA is responsible for these effects, as antisense oligonucleotide-mediated inhibition of Malat1 also suppresses Maf and IL-10 levels. Our results reveal that through promoting expression of the Maf/IL-10 axis in effector Th cells, Malat1 is a nonredundant regulator of mammalian immunity., (Copyright © 2020 The Authors.)

Macrophages have been linked to tumor initiation, progression, metastasis, and treatment resistance. However, the transcriptional regulation of macrophages driving the protumor function remains elusive. Here, we demonstrate that the transcription factor c-Maf is a critical controller for immunosuppressive macrophage polarization and function in cancer. c-Maf controls many M2-related genes and has direct binding sites within a conserved noncoding sequence of the Csf-1r gene and promotes M2-like macrophage-mediated T cell suppression and tumor progression. c-Maf also serves as a metabolic checkpoint regulating the TCA cycle and UDP-GlcNAc biosynthesis, thus promoting M2-like macrophage polarization and activation. Additionally, c-Maf is highly expressed in tumor-associated macrophages (TAMs) and regulates TAM immunosuppressive function. Deletion of c-Maf specifically in myeloid cells results in reduced tumor burden with enhanced antitumor T cell immunity. Inhibition of c-Maf partly overcomes resistance to anti-PD-1 therapy in a subcutaneous LLC tumor model. Similarly, c-Maf is expressed in human M2 and tumor-infiltrating macrophages/monocytes as well as circulating monocytes of human non-small cell lung carcinoma (NSCLC) patients and critically regulates their immunosuppressive activity. The natural compound β-glucan downregulates c-Maf expression on macrophages, leading to enhanced antitumor immunity in mice. These findings establish a paradigm for immunosuppressive macrophage polarization and transcriptional regulation by c-Maf and suggest that c-Maf is a potential target for effective tumor immunotherapy.

Beyond its well-admitted role in development and organogenesis, it is now clear that the transcription factor c-Maf has owned its place in the realm of immune-related transcription factors. Formerly introduced solely as a Th2 transcription factor, the role attributed to c-Maf has gradually broadened over the years and has extended to most, if not all, known immune cell types. The influence of c-Maf is particularly prominent among T cell subsets, where c-Maf regulates the differentiation as well as the function of multiple subsets of CD4 and CD8 T cells, lending it a crucial position in adaptive immunity and anti-tumoral responsiveness. Recent research has also revealed the role of c-Maf in controlling Th17 responses in the intestine, positioning it as an essential factor in intestinal homeostasis. This review aims to present and discuss the recent advances highlighting the particular role played by c-Maf in T lymphocyte differentiation, function, and homeostasis., (Copyright © 2020 Imbratta, Hussein, Andris and Verdeil.)

Foxp3 + regulatory T cells (T reg cells) are crucial for the maintenance of immune homeostasis both in lymphoid tissues and in non-lymphoid tissues. Here we demonstrate that the ability of intestinal T reg cells to constrain microbiota-dependent interleukin (IL)-17-producing helper T cell (T H 17 cell) and immunoglobulin A responses critically required expression of the transcription factor c-Maf. The terminal differentiation and function of several intestinal T reg cell populations, including RORγt + T reg cells and follicular regulatory T cells, were c-Maf dependent. c-Maf controlled T reg cell-derived IL-10 production and prevented excessive signaling via the kinases PI(3)K (phosphatidylinositol-3-OH kinase) and Akt and the metabolic checkpoint kinase complex mTORC1 (mammalian target of rapamycin) and expression of inflammatory cytokines in intestinal T reg cells. c-Maf deficiency in T reg cells led to profound dysbiosis of the intestinal microbiota, which when transferred to germ-free mice was sufficient to induce exacerbated intestinal T H 17 responses, even in a c-Maf-competent environment. Thus, c-Maf acts to preserve the identity and function of intestinal T reg cells, which is essential for the establishment of host-microbe symbiosis.

T follicular helper (T FH ) cells are essential for effective antibody responses, but deciphering the intrinsic wiring of mouse T FH cells has long been hampered by the lack of a reliable protocol for their generation in vitro. We report that transforming growth factor-β (TGF-β) induces robust expression of T FH hallmark molecules CXCR5 and Bcl6 in activated mouse CD4 + T cells in vitro. TGF-β-induced mouse CXCR5 + T FH cells are phenotypically, transcriptionally, and functionally similar to in vivo-generated T FH cells and provide critical help to B cells. The study further reveals that TGF-β-induced CXCR5 expression is independent of Bcl6 but requires the transcription factor c-Maf. Classical TGF-β-containing T helper 17 (T H 17)-inducing conditions also yield separate CXCR5 + and IL-17A-producing cells, highlighting shared and distinct cell fate trajectories of T FH and T H 17 cells. We demonstrate that excess IL-2 in high-density T cell cultures interferes with the TGF-β-induced T FH cell program, that T FH and T H 17 cells share a common developmental stage, and that c-Maf acts as a switch factor for T FH versus T H 17 cell fates in TGF-β-rich environments in vitro and in vivo.

Multiple myeloma (MM) is a prevalent plasma cell malignancy in the blood system that remains incurable. Given the abnormally high expression of c-Maf in most MM patients, targeting c-Maf presents an attractive therapeutic approach for treating MM malignancies. In this study, we employed a combined strategy involving molecular docking-based virtual screening, molecular dynamics (MD) simulation, and molecular mechanics/generalized Born surface area (MM/GBSA) free energy calculation on existing FDA-approved drugs. Six compounds were selected for further experimental assay: vemurafenib, sorafenib, sildenafil, fluvastatin, erlotinib, and glimepiride. Among these compounds, sorafenib and glimepiride exhibited significant inhibition of myeloma cell proliferation in the RPMI-8226 cell line. Moreover, both compounds simultaneously downregulated c-Maf protein expression to induce G1 phase arrest and apoptosis in myeloma cells. Collectively, sorafenib and glimepiride may be considered promising candidates for developing more potent c-Maf inhibitors in the future., (© 2023 John Wiley & Sons Ltd.)

Multiple myeloma displays the clonal B cell expansion and the overproduction of monoclonal immunoglobulins. Genetic translocations at 14q32, particularly with partners like 16q23, lead to the dysregulation of oncogene expression, including the significant enhancement of c-Maf. This aberrant expression of c-Maf has prompted research into strategies for targeting this transcription factor as a potential therapeutic avenue for multiple myeloma treatment. In this study, we introduce a screening pipeline to test small compounds for their ability to inhibit c-Maf. Using a luciferase indicator driven by the Ccl8 gene promoter, we identified two small compounds that inhibit transcriptional activity of c-Maf. These molecules impede the proliferation of c-Maf-expressing myeloma cells, and repress the expression of c-Maf target genes such as ITGB7 and CCR1. Importantly, these molecules target c-Maf-expressing multiple myeloma cells, but not c-Maf-negative myeloma cells, showing potential for tailoring therapeutic intervention. In conclusion, our screening pipeline is effective to explore leads for a novel c-Maf inhibitor for multiple myeloma therapy., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Kenichi Asano has patent #2021–192959 pending to Tokyo University of Pharmacy and Life Sciences., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

c-Maf is a critical oncogenic transcription factor that contributes to myelomagenesis. Our previous studies demonstrated that the deubiquitinase USP5 stabilizes c-Maf and promotes myeloma cell proliferation and survival; therefore, the USP5/c-Maf axis could be a potential target for myeloma therapy. As a concept of principle, the present study established a USP5/c-Maf-based luciferase system that was used to screen an FDA-approved drug library. It was found that mebendazole, a typical anthelmintic drug, preferentially induced apoptosis in c-Maf-expressing myeloma cells. Moreover, oral administration of mebendazole delayed the growth of human myeloma xenografts in nude mice but did not show overt toxicity. Further studies showed that the selective antimyeloma activity of mebendazole was associated with the inhibition of the USP5/c-Maf axis. Mebendazole downregulated USP5 expression and disrupted the interaction between USP5 and c-Maf, thus leading to increased levels of c-Maf ubiquitination and subsequent c-Maf degradation. Mebendazole inhibited c-Maf transcriptional activity, as confirmed by both luciferase assays and expression measurements of c-Maf downstream genes. In summary, this study identified mebendazole as a USP5/c-Maf inhibitor that could be developed as a novel antimyeloma agent.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by pathologic T cell-B cell interactions and autoantibody production. Defining the T cell populations that drive B cell responses in SLE may enable design of therapies that specifically target pathologic cell subsets. Here, we evaluated the phenotypes of CD4+ T cells in the circulation of 52 SLE patients drawn from multiple cohorts and identified a highly expanded PD-1hiCXCR5-CD4+ T cell population. Cytometric, transcriptomic, and functional assays demonstrated that PD-1hiCXCR5-CD4+ T cells from SLE patients are T peripheral helper (Tph) cells, a CXCR5- T cell population that stimulates B cell responses via IL-21. The frequency of Tph cells, but not T follicular helper (Tfh) cells, correlated with both clinical disease activity and the frequency of CD11c+ B cells in SLE patients. PD-1hiCD4+ T cells were found within lupus nephritis kidneys and correlated with B cell numbers in the kidney. Both IL-21 neutralization and CRISPR-mediated deletion of MAF abrogated the ability of Tph cells to induce memory B cell differentiation into plasmablasts in vitro. These findings identify Tph cells as a highly expanded T cell population in SLE and suggest a key role for Tph cells in stimulating pathologic B cell responses.

Background/aim: Serum-derived macrophage activating factor, serum-MAF, is known to increase the phagocytic activity of macrophages by enhancing the engulfment efficiency. To elucidate the mechanisms underlying phagocytic activation, morphological changes were observed and analyzed., Materials and Methods: Morphological changes in macrophages were observed and quantitatively analyzed using scanning electron microscope (SEM) and confocal microscope., Results: SEM and confocal microscopy images revealed frill-like structures and active actin accumulations, respectively, in serum-MAF treated macrophages. Actin accumulation was induced within 5 min following serum-MAF treatment., Conclusion: Serum-MAF induced a rapid rearrangement of cytoskeletal actin and enhanced phagocytic activity. Findings of the current study may contribute to the development of techniques that facilitate activation of the human immune system, which in turn may be beneficial for cancer immunotherapy., (Copyright© 2019, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Multiple Myeloma (MM) is a malignant hematological disease characterized by monoclonal proliferation of plasma cells in the bone marrow. In recent years, the widespread use of new drugs based on bortezomib (Btz) has significantly improved the remission rate of MM patients. However, drug resistance and disease relapse occur within a few years and MM is still considered to be an incurable disease. The amplification of the long arm of chromosome 1 is one of the most common genetic abnormalities in MM patients. Here, we found that long non-coding RNA ANGPTL1-3 which located in 1q region was overexpressed in MM. Lnc-ANGPTL1-3 expression was correlated with MM International Staging System (ISS) and overall survival. Notably, knockdown of lnc-ANGPTL1-3 increased Btz sensitivity of MM cells. Following exploration revealed that lnc-ANGPTL1-3 competitively interacted with miR-30a-3p to c-Maf, a transcription factor which was reported to be associated with Btz resistance. Taken together, our findings demonstrate that lnc-ANGPTL1-3/miR-30a-3p/c-Maf axis plays a critical role in MM Btz resistance., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The maintenance of homeostasis in the gut is a major challenge for the immune system. Here we demonstrate that the transcription factor MAF plays a central role in T cells for the prevention of gastro-intestinal inflammation. Conditional knock out mice lacking Maf in all T cells developed spontaneous late-onset colitis, correlating with a decrease of FOXP3 + RORγt + T cells proportion, dampened IL-10 production in the colon and an increase of inflammatory T H 17 cells. Strikingly, FOXP3 + specific conditional knock out mice for MAF did not develop colitis and demonstrated normal levels of IL-10 in their colon, despite the incapacity of regulatory T cells lacking MAF to suppress colon inflammation in Rag1 -/- mice transferred with naïve CD4 + T cells. We showed that one of the cellular sources of IL-10 in the colon of these mice are T H 17 cells. Thus, MAF is critically involved in the maintenance of the gut homeostasis by regulating the balance between T reg and T H 17 cells either at the level of their differentiation or through the modulation of their functions.

The transcription factor v-maf avain musculoaponeurotic fibrosarcoma oncogene homolog (MAF) plays an important role in lens development. It contains a unique extended homology region (EHR) in the DNA binding domain. MAF mutations are associated with phenotypically distinct forms of congenital cataract and show different effects on the transactivation of target genes. Mutations in the MAF EHR region were rarely reported and their corresponding phenotype and impact on target genes' transactivation were not evaluated. A three- generation Chinese family with congenital cataract was recruited. The patients in the family present non-syndromic congenital nuclear and lamellar opacities. A novel MAF mutation (c.812 T > A, p.Val271Glu) was identified by targeted next-generation sequencing. The mutation is in highly conserved EHR region of MAF and co-segregates with the cataract in the family. It is predicted to be pathogenic by multiple algorithms and is absent in a control population. Dual luciferase activity assay shows the mutation significantly impair the transcriptional activity of four crystallin genes (CRYAA, CRYBA4, CRYBA1, and CRYGA) and two non-crystallin genes (HMOX1 and KDELR2). Herein, we report a novel missense mutation in the MAF EHR region of the DNA binding domain in a family with congenital cataract. The mutation is associated with non-syndromic bilateral nuclear cataract and impacts the transactivation of cataract associated genes involved in lens structure and stress response., (Copyright © 2019 Elsevier B.V. All rights reserved.)

γδ T cells that produce the cytokine IL-17 (Tγδ17 cells) are innate-like mediators of immunity that undergo effector programming in the thymus. While regulators of Tγδ17 specialization restricted to various Vγ subsets are known, a commitment factor essential to all Tγδ17 cells has remained undefined. In this study, we identified the transcription factor c-Maf as a universal regulator of Tγδ17 cell differentiation and maintenance. Maf deficiency caused an absolute lineage block at the immature CD24 + CD45RB lo γδ thymocyte stage, which revealed a critical checkpoint in the acquisition of effector functions. Here, c-Maf enforced Tγδ17 cell identity by promoting chromatin accessibility and expression of key type 17 program genes, notably Rorc and Blk, while antagonizing the transcription factor TCF1, which promotes interferon-γ-producing γδ T cells (Tγδ1 cells). Furthermore, γδ T cell antigen receptor (γδTCR) signal strength tuned c-Maf expression, which indicates that c-Maf is a core node that connects γδTCR signals to Tγδ17 cell transcriptional programming.

SUMOylation is involved in the development of several inflammatory diseases, but the physiological significance of SUMO-modulated c-Maf in autoimmune diabetes is not completely understood. Here, we report that an age-dependent attenuation of c-Maf SUMOylation in CD4+ T cells is positively correlated with the IL-21-mediated diabetogenesis in NOD mice. Using 2 strains of T cell-specific transgenic NOD mice overexpressing wild-type c-Maf (Tg-WTc) or SUMOylation site-mutated c-Maf (Tg-KRc), we demonstrated that Tg-KRc mice developed diabetes more rapidly than Tg-WTc mice in a CD4+ T cell-autonomous manner. Moreover, SUMO-defective c-Maf preferentially transactivated Il21 to promote the development of CD4+ T cells with an extrafollicular helper T cell phenotype and expand the numbers of granzyme B-producing effector/memory CD8+ T cells. Furthermore, SUMO-defective c-Maf selectively inhibited recruitment of Daxx/HDAC2 to the Il21 promoter and enhanced histone acetylation mediated by CREB-binding protein (CBP) and p300. Using pharmacological interference with CBP/p300, we illustrated that CBP30 treatment ameliorated c-Maf-mediated/IL-21-based diabetogenesis. Taken together, our results show that the SUMOylation status of c-Maf has a stronger regulatory effect on IL-21 than the level of c-Maf expression, through an epigenetic mechanism. These findings provide new insights into how SUMOylation modulates the pathogenesis of autoimmune diabetes in a T cell-restricted manner and on the basis of a single transcription factor.

Skin-resident CD8 + T cells include distinct interferon-γ-producing [tissue-resident memory T type 1 (T RM 1)] and interleukin-17 (IL-17)-producing (T RM 17) subsets that differentially contribute to immune responses. However, whether these populations use common mechanisms to establish tissue residence is unknown. In this work, we show that T RM 1 and T RM 17 cells navigate divergent trajectories to acquire tissue residency in the skin. T RM 1 cells depend on a T-bet-Hobit-IL-15 axis, whereas T RM 17 cells develop independently of these factors. Instead, c-Maf commands a tissue-resident program in T RM 17 cells parallel to that induced by Hobit in T RM 1 cells, with an ICOS-c-Maf-IL-7 axis pivotal to T RM 17 cell commitment. Accordingly, by targeting this pathway, skin T RM 17 cells can be ablated without compromising their T RM 1 counterparts. Thus, skin-resident T cells rely on distinct molecular circuitries, which can be exploited to strategically modulate local immunity.

T cell receptor (TCR) Vγ4-expressing γδ T cells comprise interferon γ (IFNγ)- and interleukin-17 (IL-17)-producing effector subsets, with a preference for IL-17 effector fate decisions during early ontogeny. The existence of adult-thymus-derived IL-17 + T cells (γδ17) remains controversial. Here, we use a mouse model in which T cells are generated exclusively in the adult thymus and employ single-cell chromatin state analysis to study their development. We identify adult-thymus-derived Vγ4 T cells that have all the molecular programs to become IL-17 producers. However, they have reduced IL-17 production capabilities and rarely reach the periphery. Moreover, this study provides high-resolution profiles of Vγ4 T cells in the adult thymus and lymph nodes and identifies Zeb1 as a potential γδ17 cell regulator. Together, this study provides valuable insights into the developmental traits of Vγ4 T cells during adulthood and supports the idea of age-specific signals required for thymic export and/or peripheral maturation of γδ17 cells., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Different types of effector and memory T lymphocytes are induced and maintained in protective or pathological immune responses. Here we characterized two human CD4 + T H 17 helper cell subsets that, in the recently activated state, could be distinguished on the basis of their expression of the anti-inflammatory cytokine IL-10. IL-10 + T H 17 cells upregulated a variety of genes encoding immunoregulatory molecules, as well as genes whose expression is characteristic of tissue-resident T cells. In contrast, IL-10 - T H 17 cells maintained a pro-inflammatory gene-expression profile and upregulated the expression of homing receptors that guide recirculation from tissues to blood. Expression of the transcription factor c-MAF was selectively upregulated in IL-10 + T H 17 cells, and it was bound to a large set of enhancer-like regions and modulated the immunoregulatory and tissue-residency program. Our results identify c-MAF as a relevant factor that drives two highly divergent post-activation fates of human T H 17 cells and provide a framework with which to investigate the role of these cells in physiology and immunopathology.

Macrophages manifest distinct phenotype according to the organs in which they reside. In addition, they flexibly switch their character in adaptation to the changing environment. However, the molecular basis that explains the conversion of the macrophage phenotype has so far been unexplored. We find that CD169 + macrophages change their phenotype by regulating the level of a transcription factor Maf both in vitro and in vivo in C57BL/6J mice. When CD169 + macrophages were exposed to bacterial components, they expressed an array of acute inflammatory response genes in Maf-dependent manner and simultaneously start to downregulate Maf. This Maf suppression is dependent on accelerated degradation through proteasome pathway and microRNA-mediated silencing. The downregulation of Maf unlocks the NF-E2-related factor 2-dominant, cytoprotective/antioxidative program in the same macrophages. The present study provides new insights into the previously unanswered question of how macrophages initiate proinflammatory responses while retaining their capacity to repair injured tissues during inflammation., (Copyright © 2018 by The American Association of Immunologists, Inc.)

Cholesterol is a major constituent of myelin membranes, which insulate axons and allow saltatory conduction. Therefore, Schwann cells, the myelinating glia of the peripheral nervous system, need to produce large amounts of cholesterol. Here, we define a crucial role of the transcription factor Maf in myelination and cholesterol biosynthesis and show that Maf acts downstream from Neuregulin1 (Nrg1). Maf expression is induced when Schwann cells begin myelination. Genetic ablation of Maf resulted in hypomyelination that resembled mice with defective Nrg1 signaling. Importantly, loss of Maf or Nrg1 signaling resulted in a down-regulation of the cholesterol synthesis program, and Maf directly binds to enhancers of cholesterol synthesis genes. Furthermore, we identified the molecular mechanisms by which Nrg1 signaling regulates Maf levels. Transcription of Maf depends on calmodulin-dependent kinases downstream from Nrg1, whereas Nrg1-MAPK signaling stabilizes Maf protein. Our results delineate a novel signaling cascade regulating cholesterol synthesis in myelinating Schwann cells., (© 2018 Kim et al.; Published by Cold Spring Harbor Laboratory Press.)

cMaf is a leucine-zipper transcription factor that is involved in cell differentiation, oncogenic transformation, and human diseases; however, the functions of cMaf in inflammatory responses in macrophages are still not fully understood. Western blot analysis showed that cMaf expression was induced by lipopolysaccharide (LPS) stimulation in mouse macrophages. An enzyme-linked immunosorbent assay was performed to detect the level of expression of inflammatory cytokines after knockdown of cMaf expression in macrophages using a small interfering RNA (siRNA). Signaling pathway inhibitor analyses indicated that extracellular signal-related kinase and phosphoinositide 3-kinase contribute to mammalian target of rapamycin phosphorylation (mTOR), which controls cMaf expression at the translational level by regulating the expression of eIF4E-binding protein 1 and S6 ribosomal kinase 1 in response to Toll-like receptor 4 signaling. Histopathological findings of the lung and a survival analysis showed that mice transplanted with cMaf-knockdown macrophages were more susceptible to LPS challenge. Taken together, our study revealed that the control of cMaf expression at the translational level by mTOR regulated the expression of inflammatory genes in response to LPS challenge. Moreover, cMaf protected mice from septic shock indicating that cMaf may improve host fitness, thereby enabling the survival of certain infectious diseases.

Both microbial and host genetic factors contribute to the pathogenesis of autoimmune diseases. There is accumulating evidence that microbial species that potentiate chronic inflammation, as in inflammatory bowel disease, often also colonize healthy individuals. These microorganisms, including the Helicobacter species, can induce pathogenic T cells and are collectively referred to as pathobionts. However, how such T cells are constrained in healthy individuals is not yet understood. Here we report that host tolerance to a potentially pathogenic bacterium, Helicobacter hepaticus, is mediated by the induction of RORγt + FOXP3 + regulatory T (iT reg ) cells that selectively restrain pro-inflammatory T helper 17 (T H 17) cells and whose function is dependent on the transcription factor c-MAF. Whereas colonization of wild-type mice by H. hepaticus promoted differentiation of RORγt-expressing microorganism-specific iT reg cells in the large intestine, in disease-susceptible IL-10-deficient mice, there was instead expansion of colitogenic T H 17 cells. Inactivation of c-MAF in the T reg cell compartment impaired differentiation and function, including IL-10 production, of bacteria-specific iT reg cells, and resulted in the accumulation of H. hepaticus-specific inflammatory T H 17 cells and spontaneous colitis. By contrast, RORγt inactivation in T reg cells had only a minor effect on the bacteria-specific T reg and T H 17 cell balance, and did not result in inflammation. Our results suggest that pathobiont-dependent inflammatory bowel disease is driven by microbiota-reactive T cells that have escaped this c-MAF-dependent mechanism of iT reg -T H 17 homeostasis.

A bilaterally blind woman, with a three generation family history of autosomal dominant congenital cataracts, variably associated with iris colobomata and microcornea, sought preconception genetic consultation. Whole-exome sequencing was performed in three affected family members, one unaffected first degree relative, and one spouse. The sequence variant c.168C>G; p.(Tyr56∗) in CRYGD, previously reported as pathogenic, and a novel mutation c.809C>A; p.(Ser270Tyr) in MAF, were identified in two affected family members; the grandmother, and half-brother of the proband. The proband inherited only the MAF mutation, whereas her clinically unaffected sister had the CRYGD change. In silico analysis supported a pathogenic role of p.(Ser270Tyr) in MAF, which was absent from publicly available whole-exome datasets, and 1161 Czech individuals. The frequency of CRYGD p.(Tyr56∗) in the ExAC dataset was higher than the estimated incidence of congenital cataract in the general population. Our study highlights that patients with genetically heterogeneous conditions may exhibit rare variants in more than one disease-associated gene, warranting caution with data interpretation, and supporting parallel screening of all genes known to harbour pathogenic mutations for a given phenotype. The pathogenicity of sequence variants previously reported as cataract-causing may require re-assessment in light of recently released datasets of human genomic variation.

Background: Adjuvant use of bisphosphonates can reduce the incidence of bone metastases in early breast cancer. Recurrence and survival seem to be improved only in postmenopausal patients, but the underlying mechanisms remain unclear. We investigated whether MAF amplification (a biomarker for bone metastasis) in primary tumours could predict the treatment outcomes of adjuvant zoledronic acid., Methods: The study population included patients enrolled in the international, open-label, randomised, controlled, phase 3 AZURE trial at eligible UK sites who had stage II or III breast cancer and who gave consent for use of their primary tumour samples. Patients were randomly assigned (1:1) to receive standard adjuvant systemic therapy alone (control group) or with zoledronic acid every 3-4 weeks for six doses, then every 3-6 months until the end of 5 years. Minimisation took into account the number of involved axillary lymph nodes, clinical tumour stage, oestrogen-receptor status, type and timing of systemic therapy, menopausal status, statin use, and treating centre. The primary endpoint was disease-free survival; the secondary endpoint, invasive-disease-free survival, was the primary disease endpoint for the analysis in this report. MAF amplification was assessed by fluorescence in-situ hybridisation of two cores of breast tumour tissue in a microarray, done in a central laboratory by technicians unaware of treatment assignment. We used multivariate analyses to assess disease outcomes by intention to treat. We also assessed interactions between MAF-positive status and menopausal status on efficacy of zoledronic acid. The AZURE trial is registered with the International Standard Randomised Controlled Trial Registry, number ISRCTN79831382., Findings: 1739 AZURE patients contributed primary tumour samples, of whom 865 (50%) had two assessable cores (445 in the control groups and 420 in the zoledronic acid group). 184 (21%) tumours were MAF positive (85 in the control groups and 99 in the zoledronic acid group) and the remaining tumours were MAF negative. At a median follow-up of 84·6 months (IQR 72·0-95·8), MAF status was not prognostic for invasive-disease-free survival in the control group (MAF-positive vs MAF-negative: hazard ratio [HR] 0·92, 95% CI 0·59-1·41), but was in the zoledronic acid group (0·52, 0·36-0·75). In patients with MAF-negative tumours, zoledronic acid was associated with higher invasive-disease-free survival than was control treatment (HR 0·74, 95% CI 0·56-0·98), but not in patients who had MAF-positive tumours. Additionally, among 121 patients not postmenopausal at randomisation with MAF-positive tumours, zoledronic acid was associated with lower invasive-disease-free survival (HR 2·47, 95% CI 1·23-4·97) and overall survival (2·27, 95% CI 1·04-4·93) than control treatment., Interpretation: MAF status can predict likelihood of benefit from adjuvant zoledronic acid and merits further investigation as a potential companion diagnostic., Funding: Novartis Global and Inbiomotion., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Mechanisms by which interferon (IFN)-γ activates genes to promote macrophage activation are well studied, but little is known about mechanisms and functions of IFN-γ-mediated gene repression. We used an integrated transcriptomic and epigenomic approach to analyze chromatin accessibility, histone modifications, transcription-factor binding, and gene expression in IFN-γ-primed human macrophages. IFN-γ suppressed basal expression of genes corresponding to an "M2"-like homeostatic and reparative phenotype. IFN-γ repressed genes by suppressing the function of enhancers enriched for binding by transcription factor MAF. Mechanistically, IFN-γ disassembled a subset of enhancers by inducing coordinate suppression of binding by MAF, lineage-determining transcription factors, and chromatin accessibility. Genes associated with MAF-binding enhancers were suppressed in macrophages isolated from rheumatoid-arthritis patients, revealing a disease-associated signature of IFN-γ-mediated repression. These results identify enhancer inactivation and disassembly as a mechanism of IFN-γ-mediated gene repression and reveal that MAF regulates the macrophage enhancer landscape and is suppressed by IFN-γ to augment macrophage activation., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: UBE2O is proposed as a ubiquitin-conjugating enzyme, but its function was largely unknown., Methods: Mass spectrometry was applied to identify c-Maf ubiquitination-associated proteins. Immunoprecipitation was applied for c-Maf and UBE2O interaction. Immunoblotting was used for Maf protein stability. Luciferase assay was used for c-Maf transcriptional activity. Lentiviral infections were applied for UBE2O function in multiple myeloma (MM) cells. Flow cytometry and nude mice xenografts were applied for MM cell apoptosis and tumor growth assay, respectively., Results: UBE2O was found to interact with c-Maf, a critical transcription factor in MM, by the affinity purification/tandem mass spectrometry assay and co-immunoprecipitation assays. Subsequent studies showed that UBE2O mediated c-Maf polyubiquitination and degradation. Moreover, UBE2O downregulated the transcriptional activity of c-Maf and the expression of cyclin D2, a typical gene modulated by c-Maf. DNA microarray revealed that UBE2O was expressed in normal bone marrow cells but downregulated in MGUS, smoldering MM and MM cells, which was confirmed by RT-PCR in primary MM cells, suggesting its potential role in myeloma pathophysiology. When UBE2O was restored, c-Maf protein in MM cells was significantly decreased and MM cells underwent apoptosis. Furthermore, the human MM xenograft in nude mice showed that re-expression of UBE2O delayed the growth of myeloma xenografts in nude mice in association with c-Maf downregulation and activation of the apoptotic pathway., Conclusions: UBE2O mediates c-Maf polyubiquitination and degradation, induces MM cell apoptosis, and suppresses myeloma tumor growth, which provides a novel insight in understanding myelomagenesis and UBE2O biology.

Numerous regulatory factors in epidermal differentiation and their role in regulating different cell states have been identified in recent years. However, the genetic interactions between these regulators over the dynamic course of differentiation have not been studied. In this Extra-View article, we review recent work by Lopez-Pajares et al. that explores a new regulatory network in epidermal differentiation. They analyze the changing transcriptome throughout epidermal regeneration to identify 3 separate gene sets enriched in the progenitor, early and late differentiation states. Using expression module mapping, MAF along with MAFB, are identified as transcription factors essential for epidermal differentiation. Through double knock-down of MAF:MAFB using siRNA and CRISPR/Cas9-mediated knockout, epidermal differentiation was shown to be impaired both in-vitro and in-vivo, confirming MAF:MAFB's role to activate genes that drive differentiation. Lopez-Pajares and collaborators integrated 42 published regulator gene sets and the MAF:MAFB gene set into the dynamic differentiation gene expression landscape and found that lncRNAs TINCR and ANCR act as upstream regulators of MAF:MAFB. Furthermore, ChIP-seq analysis of MAF:MAFB identified key transcription factor genes linked to epidermal differentiation as downstream effectors. Combined, these findings illustrate a dynamically regulated network with MAF:MAFB as a crucial link for progenitor gene repression and differentiation gene activation.

Myofibers are broadly characterized as fatigue-resistant slow-twitch (type I) fibers and rapidly fatiguing fast-twitch (type IIa/IIx/IIb) fibers. However, the molecular regulation of myofiber type is not entirely understood; particularly, information on regulators of fast-twitch muscle is scarce. Here, we demonstrate that the large Maf transcription factor family dictates fast type IIb myofiber specification in mice. Remarkably, the ablation of three large Mafs leads to the drastic loss of type IIb myofibers, resulting in enhanced endurance capacity and the reduction of muscle force. Conversely, the overexpression of each large Maf in the type I soleus muscle induces type IIb myofibers. Mechanistically, a large Maf directly binds to the Maf recognition element on the promoter of myosin heavy chain 4, which encodes the type IIb myosin heavy chain, driving its expression. This work identifies the large Maf transcription factor family as a major regulator for fast type IIb muscle determination., Competing Interests: Declaration of interests T.K., D.S., and S. Takahashi are inventors on a patent application related to this work (patent application no. 2022-083553)., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Corticospinal tract (CST) neurons innervate the deep spinal dorsal horn to sustain chronic neuropathic pain. The majority of neurons targeted by the CST are interneurons expressing the transcription factor c-Maf. Here, we used intersectional genetics to decipher the function of these neurons in dorsal horn sensory circuits. We find that excitatory c-Maf (c-Maf EX ) neurons receive sensory input mainly from myelinated fibers and target deep dorsal horn parabrachial projection neurons and superficial dorsal horn neurons, thereby connecting non-nociceptive input to nociceptive output structures. Silencing c-Maf EX neurons has little effect in healthy mice but alleviates mechanical hypersensitivity in neuropathic mice. c-Maf EX neurons also receive input from inhibitory c-Maf and parvalbumin neurons, and compromising inhibition by these neurons caused mechanical hypersensitivity and spontaneous aversive behaviors reminiscent of c-Maf EX neuron activation. Our study identifies c-Maf EX neurons as normally silent second-order nociceptors that become engaged in pathological pain signaling upon loss of inhibitory control., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)