Trim33 mediates the proinflammatory function of Th17 cells

KLHL25-ACLY module functions as a switch in the fate determination of the differentiation of iTreg/Th17

The differentiation of Th17 and iTreg is tightly associated with fatty acid metabolism. TGFβ1-induced iTreg differentiation from Th0 relies on fatty acid oxidation (FAO), whereas IL-6 with TGFβ1 shifts metabolism to Th17-preferred fatty acid synthesis (FAS). However, how IL-6 reprograms fatty acid metabolism remains unclear. Here, we unveiled that TGFβ1-activated JNK is recruited to the Klhl25 promoter by NF-YA. JNK then phosphorylates histone H3 at Ser10 to activate Klhl25 transcription, leading to the ubiquitination-dependent degradation of ATP-citrate lyase (ACLY) and the switch from FAS to FAO, which supports iTreg generation. Whereas, upon IL-6 signaling, NF-YA is phosphorylated by ERK, losing its DNA binding ability, which shuts off TGFβ1-JNK-mediated Klhl25 transcription and ACLY ubiquitination, thereby increasing FAS and supporting Th17 differentiation. This study demonstrated that KLHL25-ACLY module functions as a switch in response to TGFβ1 and IL-6 signals, playing a decisive role in the fate determination of iTreg/Th17 differentiation.

Interaction between Th17 and central nervous system in multiple sclerosis

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TRIM28 is an essential regulator of three-dimensional chromatin state underpinning CD8+ T cell activation

T cell activation is accompanied by extensive changes in epigenome. However, the high-ordered chromatin organization underpinning CD8+ T cell activation is not fully known. Here, we show extensive changes in the three-dimensional genome during CD8+ T cell activation, associated with changes in gene transcription. We show that CD8+ T-cell-specific deletion of Trim28 in mice disrupts autocrine IL-2 production and leads to impaired CD8+ T cell activation in vitro and in vivo. Mechanistically, TRIM28 binds to regulatory regions of genes associated with the formation of chromosomal loops during activation. At the loop anchor regions, TRIM28-occupancy overlaps with that of CTCF, a factor known for defining the boundaries of topologically associating domains and for forming of the loop anchors. In the absence of Trim28, RNA Pol II and cohesin binding to these regions diminishes, and the chromosomal structure required for the active state is disrupted. These results thus identify a critical role for TRIM28-dependent chromatin topology in gene transcription in activated CD8+ T cells.

An intestinal TH17 cell-derived subset can initiate cancer

Approximately 25% of cancers are preceded by chronic inflammation that occurs at the site of tumor development. However, whether this multifactorial oncogenic process, which commonly occurs in the intestines, can be initiated by a specific immune cell population is unclear. Here, we show that an intestinal T cell subset, derived from interleukin-17 (IL-17)-producing helper T (TH17) cells, induces the spontaneous transformation of the intestinal epithelium. This subset produces inflammatory cytokines, and its tumorigenic potential is not dependent on IL-17 production but on the transcription factors KLF6 and T-BET and interferon-γ. The development of this cell type is inhibited by transforming growth factor-β1 (TGFβ1) produced by intestinal epithelial cells. TGFβ signaling acts on the pretumorigenic TH17 cell subset, preventing its progression to the tumorigenic stage by inhibiting KLF6-dependent T-BET expression. This study therefore identifies an intestinal T cell subset initiating cancer.

Advances in non-type 2 severe asthma: from molecular insights to novel treatment strategies

Asthma is a prevalent pulmonary disease that affects more than 300 million people worldwide and imposes a substantial economic burden. While medication can effectively control symptoms in some patients, severe asthma attacks, driven by airway inflammation induced by environmental and infectious exposures, continue to be a major cause of asthma-related mortality. Heterogeneous phenotypes of asthma include type 2 (T2) and non-T2 asthma. Non-T2 asthma is often observed in patients with severe and/or steroid-resistant asthma. This review covers the molecular mechanisms, clinical phenotypes, causes and promising treatments of non-T2 severe asthma. Specifically, we discuss the signalling pathways for non-T2 asthma including the activation of inflammasomes, interferon responses and interleukin-17 pathways, and their contributions to the subtypes, progression and severity of non-T2 asthma. Understanding the molecular mechanisms and genetic determinants underlying non-T2 asthma could form the basis for precision medicine in severe asthma treatment.

TRIM33 plays a critical role in regulating dendritic cell differentiation and homeostasis by modulating Irf8 and Bcl2l11 transcription

The development of distinct dendritic cell (DC) subsets, namely, plasmacytoid DCs (pDCs) and conventional DC subsets (cDC1s and cDC2s), is controlled by specific transcription factors. IRF8 is essential for the fate specification of cDC1s. However, how the expression of Irf8 is regulated is not fully understood. In this study, we identified TRIM33 as a critical regulator of DC differentiation and maintenance. TRIM33 deletion in Trim33fl/fl Cre-ERT2 mice significantly impaired DC differentiation from hematopoietic progenitors at different developmental stages. TRIM33 deficiency downregulated the expression of multiple genes associated with DC differentiation in these progenitors. TRIM33 promoted the transcription of Irf8 to facilitate the differentiation of cDC1s by maintaining adequate CDK9 and Ser2 phosphorylated RNA polymerase II (S2 Pol II) levels at Irf8 gene sites. Moreover, TRIM33 prevented the apoptosis of DCs and progenitors by directly suppressing the PU.1-mediated transcription of Bcl2l11, thereby maintaining DC homeostasis. Taken together, our findings identified TRIM33 as a novel and crucial regulator of DC differentiation and maintenance through the modulation of Irf8 and Bcl2l11 expression. The finding that TRIM33 functions as a critical regulator of both DC differentiation and survival provides potential benefits for devising DC-based immune interventions and therapies.

STAT3 and SOX-5 induce BRG1-mediated chromatin remodeling of RORCE2 in Th17 cells

Retinoid-related orphan receptor gamma t (RORγt) is the lineage-specific transcription factor for T helper 17 (Th17) cells. Our previous study demonstrated that STAT3 likely participates in the activation of RORCE2 (a novel enhancer of the RORγt gene) in Th17 cells. However, the detailed mechanism is still unclear. Here, we demonstrate that both STAT3 and SOX-5 mediate the enhancer activity of RORCE2 in vitro. Deletion of the STAT3 binding site (STAT3-BS) in RORCE2 impaired RORγt expression and Th17 differentiation, resulting in reduced severity of experimental autoimmune encephalomyelitis (EAE). Mechanistically, STAT3 and SOX-5 bind the RORCE2 region and recruit the chromatin remodeling factor BRG1 to remodel the nucleosomes positioned at this region. Collectively, our data suggest that STAT3 and SOX-5 mediate the differentiation of Th17 cells through the induction of BRG1-mediated chromatin remodeling of RORCE2 in Th17 cells.

Elimination of Chlamydia muridarum from the female reproductive tract is IL-12p40 dependent, but independent of Th1 and Th2 cells

Chlamydia vaccine approaches aspire to induce Th1 cells for optimal protection, despite the fact that there is no direct evidence demonstrating Th1-mediated Chlamydia clearance from the female reproductive tract (FRT). We recently reported that T-bet-deficient mice can resolve primary Chlamydia infection normally, undermining the potentially protective role of Th1 cells in Chlamydia immunity. Here, we show that T-bet-deficient mice develop robust Th17 responses and that mice deficient in Th17 cells exhibit delayed bacterial clearance, demonstrating that Chlamydia-specific Th17 cells represent an underappreciated protective population. Additionally, Th2-deficient mice competently clear cervicovaginal infection. Furthermore, we show that sensing of IFN-γ by non-hematopoietic cells is essential for Chlamydia immunity, yet bacterial clearance in the FRT does not require IFN-γ secretion by CD4 T cells. Despite the fact that Th1 cells are not necessary for Chlamydia clearance, protective immunity to Chlamydia is still dependent on MHC class-II-restricted CD4 T cells and IL-12p40. Together, these data point to IL-12p40-dependent CD4 effector maturation as essential for Chlamydia immunity, and Th17 cells to a lesser extent, yet neither Th1 nor Th2 cell development is critical. Future Chlamydia vaccination efforts will be more effective if they focus on induction of this protective CD4 T cell population.

The Immune Modulatory Role of TIF1 Proteins

The function of immune cells is delicately regulated under a variety of molecular networks. Transcriptional intermediary factor 1 (TIF1) family proteins, consisting of TRIM24, TRIM28 and TRIM33, share a highly conserved RING domain that is essential for the regulation of protein ubiquitination functioning as E3 ubiquitin ligases. TIF1 family proteins are diversely expressed in different types of immune cells, and participate in the regulation of various of cellular functions including chromosome modification, DNA repair, tumor progression, and immunity. In this review, we summarized current studies on TIF1 family proteins' functions in the modulation of immune cell development, anti-infection immunity, cancer immunology, inflammation, and autoimmune diseases.

Clinical features of dermatomyositis patients with anti-TIF1 antibodies: A case based comprehensive review

BACKGROUND AND OBJECTIVES

Dermatomyositis is chronic autoimmune disease primarily affecting skin and muscles. Antibodies are key players of pathogenesis and are in strong correlation with distinct clinical phenotypes. We present a case and a comprehensive review of the literature on dermatomyositis patients with Anti TIF1 antibodies.

METHODS

PubMed and Web of Science databases were reviewed. 166 articles were identified; 95 of them were evaluated; 79 of them included to the study. 45 of the included articles were case reports 9 were case series and 25 were research articles. In total 1065 patients were identified but number of patients with available information for different clinical features varied.

RESULTS

69.6% of the patients with Anti TIF1-γ were female. Prevalence of malignancy was 42.6% among patients with Anti TIF1-γ. Muscle weakness (83%), Gottron sign (82.2%), heliotrope rash (73.7%), nailfold capillary changes (67.7%), dysphagia (38.4%), and joint involvement (31.1%) were the most common clinical features seen in patients with Anti TIF1-γ. Interstitial lung disease (ILD) was reported among 8.7% of patients with Anti TIF1-γ. Advanced age, male gender, dysphagia, and V-neck rash were significant risk factors for malignancy, whereas juvenile age, ILD, TIF1-β antibodies and joint involvement were associated with a decreased risk for malignancy. Advanced age, malignancy, dysphagia, and muscle involvement were associated with an increased risk for mortality.

CONCLUSIONS

Patients with advanced age, male gender, dysphagia, and V-neck rash require strict cancer screening. Patients with advanced age, malignancy, dysphagia, and muscle involvement have poor prognosis and should receive aggressive treatment.

Silicon-Based Biomaterials Modulate the Adaptive Immune Response of T Lymphocytes to Promote Osteogenesis/Angiogenesis via Epigenetic Regulation

Silicon (Si)-based biomaterials are widely applied for bone regeneration. However, the underlying mechanisms of the materials function remain largely unknown. T lymphocyte-mediated adaptive immune response plays a vital role in the process of bone regeneration. In the current study, mesoporous silica (MS) is used as a model material of Si-based biomaterials. It shows that the supernatant of CD4+ T lymphocytes pretreated with MS extract significantly promotes the vascularized bone regeneration. The potential mechanism is closely related to the fact that MS extract can reduce the expression of regulatory factor X-1 (RFX-1) in CD4+ T lymphocytes. This may result in the overexpression of interleukin-17A (IL-17A) by boosting histone H3 acetylation and lowering DNA methylation and H3K9 trimethylation. Importantly, the in vivo experiments further reveal that MS particles significantly enhance bone regeneration with improved angiogenesis in the critical-sized calvarial defect mouse model accompanied by upregulation of IL-17A in peripheral blood and the proportion of Th17 cells. This study suggests that modulation of the adaptive immune response of T lymphocytes by silicate-based biomaterials plays an important role for bone regeneration.

TGF-β1 signaling and Smad7 control T-cell responses in health and immune-mediated disorders

Transforming growth factor (TGF)-β1, a member of the TGF-β superfamily, is produced by many immune and nonimmune cells and has pleiotropic effects on both innate and adaptive immunity, especially in the control of T-cell differentiation and function. Consistently, loss of TGF-β1 function is associated with exacerbated T-cell-dependent inflammatory responses that culminate in pathological processes in allergic and immune-mediated diseases. In this review, we highlight the roles of TGF-β1 in immunity, focusing mainly on its ability to promote differentiation of regulatory T cells, T helper (Th)-17, and Th9 cells, thus contributing to amplifying or restricting T-cell responses in health and human diseases (e.g., inflammatory bowel diseases, type 1 diabetes, asthma, and MS). In addition, we discuss the involvement of Smad7, an inhibitor of TGF-β1 signaling, in immune-mediated disorders (e.g., psoriasis, rheumatoid arthritis, MS, and inflammatory bowel diseases), as well as the discordant results of clinical trials with mongersen, an oral pharmaceutical compound containing a Smad7 antisense oligonucleotide, in patients with Crohn's disease. Further work is needed to ascertain the reasons for such a discrepancy as well as to identify better candidates for treatment with Smad7 inhibitors.

Mechanism of BLIMP1/TRIM66/COX2 in human decidua participates in parturition†

The mechanism underlying the initiation of parturition remains unclear. Cyclooxygenase 2 and prostaglandins in decidual membrane tissue play an important role in the "parturition cascade." With the advancement of gestation, the expression of the transcriptional suppressor B lymphocyte-induced maturation protein 1 in the decidual membrane gradually decreases. Through chromatin immunoprecipitation sequencing, we found that B lymphocyte-induced maturation protein 1 has a binding site in the distal intergenic of PTGS2(COX2). Tripartite motif-containing protein 66 is a chromatin-binding protein that usually performs transcriptional regulatory functions by "reading" histone modification sites in chromatin. In this study, tripartite motif-containing protein 66 exhibits the same trend of expression as B lymphocyte-induced maturation protein 1 in the decidua during gestation. Moreover, the co-immunoprecipitation assay revealed that tripartite motif-containing protein 66 combined with B lymphocyte-induced maturation protein 1. This finding indicated that tripartite motif-containing protein 66 formed a transcription complex with B lymphocyte-induced maturation protein 1, which coregulated the expression of COX2. In animal experiments, we injected si-Blimp1 adenoviruses (si-Blimp1), Blimp1 overexpression plasmid (Blimp1-OE), and Trim66 overexpression plasmid (Trim66-OE) through the tail vein of mice. The results showed that B lymphocyte-induced maturation protein 1 and tripartite motif-containing protein 66 affected the initiation of parturition in mice. Therefore, the present evidence suggests that B lymphocyte-induced maturation protein 1 and tripartite motif-containing protein 66 partially participate in the initiation of labor, which may provide a new perspective for exploring the mechanism of term labor.

Intricacies of TGF-β signaling in Treg and Th17 cell biology

Balanced immunity is pivotal for health and homeostasis. CD4+ helper T (Th) cells are central to the balance between immune tolerance and immune rejection. Th cells adopt distinct functions to maintain tolerance and clear pathogens. Dysregulation of Th cell function often leads to maladies, including autoimmunity, inflammatory disease, cancer, and infection. Regulatory T (Treg) and Th17 cells are critical Th cell types involved in immune tolerance, homeostasis, pathogenicity, and pathogen clearance. It is therefore critical to understand how Treg and Th17 cells are regulated in health and disease. Cytokines are instrumental in directing Treg and Th17 cell function. The evolutionarily conserved TGF-β (transforming growth factor-β) cytokine superfamily is of particular interest because it is central to the biology of both Treg cells that are predominantly immunosuppressive and Th17 cells that can be proinflammatory, pathogenic, and immune regulatory. How TGF-β superfamily members and their intricate signaling pathways regulate Treg and Th17 cell function is a question that has been intensely investigated for two decades. Here, we introduce the fundamental biology of TGF-β superfamily signaling, Treg cells, and Th17 cells and discuss in detail how the TGF-β superfamily contributes to Treg and Th17 cell biology through complex yet ordered and cooperative signaling networks.

Akkermansia muciniphila, which is enriched in the gut microbiota by metformin, improves cognitive function in aged mice by reducing the proinflammatory cytokine interleukin-6

BACKGROUND

Metformin, a type 2 diabetes treatment, improves the cognitive function of aged mice; however, whether the protective effects of metformin on cognitive function in aged mice are associated with the gut microbiome is poorly understood. Although some studies suggest that the gut microbe composition influences cognitive function and that manipulating the gut microbiota might protect against age-related cognitive dysfunction, there is no direct evidence to validate that the gut microbiota mediates the effect of metformin on cognitive improvement.

RESULTS

In this study, we show that the gut microbiota is altered by metformin, which is necessary for protection against ageing-associated cognitive function declines in aged mice. Mice treated with antibiotics did not exhibit metformin-mediated cognitive function protection. Moreover, treatment with Akkermansia muciniphila, which is enriched by metformin, improved cognitive function in aged mice. Mechanistically, A. muciniphila decreased pro-inflammatory-associated pathways, particularly that of the pro-inflammatory cytokine interleukin (IL)-6, in both the peripheral blood and hippocampal profiles, which was correlated with cognitive function improvement. An IL-6 antibody protected cognitive function, and an IL-6 recombinant protein abolished the protective effect of A. muciniphila on cognitive function in aged mice.

CONCLUSION

This study reveals that A. muciniphila, which is mediated in the gut microbiota by metformin, modulates inflammation-related pathways in the host and improves cognitive function in aged mice by reducing the pro-inflammatory cytokine IL-6. Video Abstract.

NR3C1 overexpression regulates the expression and alternative splicing of inflammation-associated genes involved in PTSD

NR3C1-encoding glucocorticoid receptors have dual roles as RNA-binding protein and transcription factor. Recent studies revealed that NR3C1 might play an important role in the pathogenesis of PTSD (Post-traumatic stress disorder). However, its molecular mechanism remained unclear. In the present study, a neuronal cell model was constructed by transfecting a NR3C1-overexpressing plasmid pIRES-hrGFP-1a-NR3C1 or empty vector into HT22 cells. The changes in global transcription levels and alternative splicing events in HT22 cells after NR3C1 overexpression were analyzed by RNA sequencing. Compared with the empty vector control, the expression of inflammatory factors were differentially regulated by NR3C1, including genes involved in chemokine signal pathway, PI3K-Akt signal pathway, cytokine receptor interaction, neural ligand-receptor interaction and so on. In addition, NR3C1 regulated the alternative splicing of many genes involved in immune response, axon formation, stress response and inflammation. This study was the first to perform a transcriptome analysis of differential gene expression and alternative splicing in a NR3C1-overexpressing HT22 cell model. Our results suggested that NR3C1 could manipulate the expression of inflammatory transcription factors and their alternative splicing patterns, subsequently affecting the expression of downstream targets, may be leading to the onset of PTSD. This study will provide new insights in the NR3C1-mediated gene regulation in relation to PTSD.

To Ub or not to Ub: a regulatory question in TGF-β signaling

The transforming growth factor β (TGF-β) superfamily controls a wide spectrum of biological processes in metazoans, including cell proliferation, apoptosis, differentiation, cell-fate determination, and embryonic development. Deregulation of TGF-β-Smad signaling contributes to developmental anomalies and a variety of disorders and diseases such as tumorigenesis, fibrotic disorders, and immune diseases. In cancer, TGF-β has dual effects through its antiproliferative and prometastatic actions. At the cellular level, TGF-β functions mainly through the canonical Smad-dependent pathway in a cell type-specific and context-dependent manner. Accumulating evidence has demonstrated that ubiquitination plays a vital role in regulating TGF-β-Smad signaling. We summarize current progress on ubiquitination (Ub) and the ubiquitin ligases that regulate TGF-β-Smad signaling.

E3 ubiquitin ligase Trim33 ubiquitylates Annexin A2 to promote NF-κB induced skin inflammation in psoriasis

BACKGROUND

Tripartite motif-containing protein 33, a member of the TRIM E3 ligase family, is shown to be involved in tumorigenesis, cell proliferation and inflammation. Alteration of several TRIM family proteins in psoriatic epidermis has been shown to participate in psoriasis pathogenesis. However, little is known about Trim33 expression and its role in psoriasis.

OBJECTIVES

To examine the expression and biological roles of Trim33 in psoriatic process, with a focus on identifying its novel substrates in psoriatic keratinocytes.

METHODS

Gene expression of Trim33 in biopsies from psoriasis patients compared with healthy volunteers was analysed by quantitative real-time polymerase chain reaction (qPCR) and immunofluorescence (IF). Identification of Trim33 substrates were performed using immunoprecipitation combined with mass spectrometry. Protein expression and localization were assessed by immunoblotting and immunofluorescence. Expression of cytokines was analysed with qPCR.

RESULTS

qPCR and IF analysis revealed increased expression of Trim33 in psoriatic epidermis. Overexpression of Trim33 promoted the expression of psoriasis-related proinflammatory cytokines IL-6, IL-1β and NLRP3 inflammasome. Intriguingly, Trim33 induced lysine 63 (K63)-linked ubiquitination of Annexin A2 (Anxa2), which promoted its interaction with p50/p65 subunits of NF-κB, favoured the retention of p50/p65 in the nucleus and promoted the expression of inflammation-related NF-κB downstream genes.

CONCLUSIONS

Our study highlights the upregulation of Trim33 in psoriatic epidermis and its pivotal role in promoting the inflammation of keratinocytes by Anxa2/NF-κB pathway. Our findings imply that Trim33 might be further explored as potential target for psoriasis treatment.

IL-10 in glioma

The prognosis for patients with glioblastoma (GBM), the most common and malignant type of primary brain tumour, is very poor, despite current standard treatments such as surgery, radiotherapy and chemotherapy. Moreover, the immunosuppressive tumour microenvironment hinders the development of effective immunotherapies for GBM. Cytokines such as interleukin-10 (IL-10) play a major role in modulating the activity of infiltrating immune cells and tumour cells in GBM, predominantly conferring an immunosuppressive action; however, in some circumstances, IL-10 can have an immunostimulatory effect. Elucidating the function of IL-10 in GBM is necessary to better strategise and improve the efficacy of immunotherapy. This review discusses the immunostimulatory and immunosuppressive roles of IL-10 in the GBM tumour microenvironment while considering IL-10-targeted treatment strategies. The molecular mechanisms that underlie the expression of IL-10 in various cell types are also outlined, and how this resulting information might provide an avenue for the improvement of immunotherapy in GBM is explored.

Plasma Based Protein Signatures Associated with Small Cell Lung Cancer

Small-cell-lung cancer (SCLC) is associated with overexpression of oncogenes including Myc family genes and YAP1 and inactivation of tumor suppressor genes. We performed in-depth proteomic profiling of plasmas collected from 15 individuals with newly diagnosed early stage SCLC and from 15 individuals before the diagnosis of SCLC and compared findings with plasma proteomic profiles of 30 matched controls to determine the occurrence of signatures that reflect disease pathogenesis. A total of 272 proteins were elevated (area under the receiver operating characteristic curve (AUC) ≥ 0.60) among newly diagnosed cases compared to matched controls of which 31 proteins were also elevated (AUC ≥ 0.60) in case plasmas collected within one year prior to diagnosis. Ingenuity Pathway analyses of SCLC-associated proteins revealed enrichment of signatures of oncogenic MYC and YAP1. Intersection of proteins elevated in case plasmas with proteomic profiles of conditioned medium from 17 SCLC cell lines yielded 52 overlapping proteins characterized by YAP1-associated signatures of cytoskeletal re-arrangement and epithelial-to-mesenchymal transition. Among samples collected more than one year prior to diagnosis there was a predominance of inflammatory markers. Our integrated analyses identified novel circulating protein features in early stage SCLC associated with oncogenic drivers.

Increased Interleukin-10 Expression by the Inhibition of Ca2+-Activated K+ Channel KCa3.1 in CD4+CD25+ Regulatory T Cells in the Recovery Phase in an Inflammatory Bowel Disease Mouse Model

Inflammatory bowel diseases (IBD) are chronic inflammatory diseases of the gastrointestinal tract arising from abnormal responses of the innate and adaptative immune systems. Interleukin (IL)-10-producing CD4+CD25+ regulatory T (Treg) cells play a protective role in the recovery phase of IBD. In the present study, the effects of the administration of the selective Ca2+-activated K+ channel KCa3.1 inhibitor TRAM-34 on disease activities were examined in chemically induced IBD model mice. IBD disease severity, as assessed by diarrhea, visible fecal blood, inflammation, and crypt damage in the colon, was significantly lower in mice administered 1 mg/kg TRAM-34 than in vehicle-administered mice. Quantitative real-time polymerase chain reaction examinations showed that IL-10 expression levels in the recovery phase were markedly increased by the inhibition of KCa3.1 in mesenteric lymph node (mLN) Treg cells of IBD model mice compared with vehicle-administered mice. Among several positive and negative transcriptional regulators (TRs) for IL-10, three positive TRs-E4BP4, KLF4, and Blimp1-were upregulated by the inhibition of KCa3.1 in the mLN Treg cells of IBD model mice. In mouse peripheral CD4+CD25+ Treg cells induced by lectin stimulation, IL-10 expression and secretion were enhanced by the treatment with TRAM-34, together with the upregulation of E4BP4, KLF4, and Blimp1. Collectively, the present results demonstrated that the pharmacological inhibition of KCa3.1 decreased IBD symptoms in the IBD model by increasing IL-10 production in peripheral Treg cells and that IL-10high Treg cells produced by the treatment with KCa3.1 inhibitor may contribute to efficient Treg therapy for chronic inflammatory disorders, including IBD. SIGNIFICANCE STATEMENT: Pharmacological inhibition of Ca2+-activated K+ channel KCa3.1 increased IL-10 expression in peripheral Treg cells, together with the upregulation of the transcriptional regulators of IL-10: Krüppel-like factor 4, E4 promoter-binding protein 4, and/or B lymphocyte-induced maturation protein 1. The manipulation of IL-10high-producing Treg cells by the pharmacological inhibition of KCa3.1 may be beneficial in the treatment of chronic inflammatory diseases such as inflammatory bowel disease.

Insights into the mechanisms of Th17 differentiation and the Yin-Yang of Th17 cells in human diseases

Th17 cells are a lineage of CD4⁺ T helper cells with Th17-specific transcription factors RORγt and RoRα. Since its discovery in 2005, research on Th17 has been in rapid progress, and increasing cytokines or transcription factors have been uncovered in the activation and differentiation of Th17 cells. Furthermore, growing evidence proves there are two different subsets of Th17 cells, namely non-pathogenic Th17 (non-pTh17) and pathogenic Th17 (pTh17), both of which play important roles in adaptive immunity, especially in host defenses, autoimmune diseases, and cancer. In this review, we summarize and discuss the mechanisms of Th17 cells differentiation, and their roles in immunity and diseases.

Cell type-specific modulation of healthspan by Forkhead family transcription factors in the nervous system

Reduced activity of insulin/insulin-like growth factor signaling (IIS) increases healthy lifespan among diverse animal species. Downstream of IIS, multiple evolutionarily conserved transcription factors (TFs) are required; however, distinct TFs are likely responsible for these effects in different tissues. Here we have asked which TFs can extend healthy lifespan within distinct cell types of the adult nervous system in Drosophila Starting from published single-cell transcriptomic data, we report that forkhead (FKH) is endogenously expressed in neurons, whereas forkhead-box-O (FOXO) is expressed in glial cells. Accordingly, we find that neuronal FKH and glial FOXO exert independent prolongevity effects. We have further explored the role of neuronal FKH in a model of Alzheimer's disease-associated neuronal dysfunction, where we find that increased neuronal FKH preserves behavioral function and reduces ubiquitinated protein aggregation. Finally, using transcriptomic profiling, we identify Atg17, a member of the Atg1 autophagy initiation family, as one FKH-dependent target whose neuronal overexpression is sufficient to extend healthy lifespan. Taken together, our results underscore the importance of cell type-specific mapping of TF activity to preserve healthy function with age.

The Role of Ubiquitin E3 Ligase in Atherosclerosis

Atherosclerosis is a chronic inflammatory vascular disease. Atherosclerotic cardiovascular disease is the main cause of death in both developed and developing countries. Many pathophysiological factors, including abnormal cholesterol metabolism, vascular inflammatory response, endothelial dysfunction and vascular smooth muscle cell proliferation and apoptosis, contribute to the development of atherosclerosis and the molecular mechanisms underlying the development of atherosclerosis are not fully understood. Ubiquitination is a multistep post-translational protein modification that participates in many important cellular processes. Emerging evidence suggests that ubiquitination plays important roles in the pathogenesis of atherosclerosis in many ways, including regulation of vascular inflammation, endothelial cell and vascular smooth muscle cell function, lipid metabolism and atherosclerotic plaque stability. This review summarizes important contributions of various E3 ligases to the development of atherosclerosis. Targeting ubiquitin E3 ligases may provide a novel strategy for the prevention of the progression of atherosclerosis.

Cytokine Regulation and Function in T Cells

T lymphocytes, the major effector cells in cellular immunity, produce cytokines in immune responses to mediate inflammation and regulate other types of immune cells. Work in the last three decades has revealed significant heterogeneity in CD4⁺ T cells, in terms of their cytokine expression, leading to the discoveries of T helper 1 (Th1), Th2, Th17, and T follicular helper (Tfh) cell subsets. These cells possess unique developmental and regulatory pathways and play distinct roles in immunity and immune-mediated pathologies. Other types of T cells, including regulatory T cells and γδ T cells, as well as innate lymphocytes, display similar features of subpopulations, which may play differential roles in immunity. Mechanisms exist to prevent cytokine production by T cells to maintain immune tolerance to self-antigens, some of which may also underscore immune exhaustion in the context of tumors. Understanding cytokine regulation and function has offered innovative treatment of many human diseases.

Replicated umbilical cord blood DNA methylation loci associated with gestational age at birth

DNA methylation is highly sensitive to in utero perturbations and has an established role in both embryonic development and regulation of gene expression. The foetal genetic component has been previously shown to contribute significantly to the timing of birth, yet little is known about the identity and behaviour of individual genes. The aim of this study was to test the extent genome-wide DNA methylation levels in umbilical cord blood were associated with gestational age at birth (GA). Findings were validated in an independent sample and evidence for the regulation of gene expression was evaluated for cis gene relationships in specimens with multi-omic data. Genome-wide DNA methylation, measured by the Illumina Infinium Human Methylation 450 K BeadChip, was associated with GA for 2,372 CpG probes (5% FDR) in both the Pregnancy, Race, Environment, Genes (PREG) and Newborn Epigenetic Study (NEST) cohorts. Significant probes mapped to 1,640 characterized genes and an association with nearby gene expression measures obtained by the Affymetrix HG-133A microarray was found for 11 genes. Differentially methylated positions were enriched for actively transcribed and enhancer chromatin states, were predominately located outside of CpG islands, and mapped to genes enriched for inflammation and innate immunity ontologies. In both PREG and NEST, the first principal component derived from these probes explained approximately one-half (58.1% and 47.8%, respectively) of the variation in GA. Gene pathways identified are consistent with the hypothesis of pathogen detection and response by the immune system to elicit premature labour as a consequence of unscheduled inflammation.

Unraveling the blood transcriptome after real-life exposure of Wistar-rats to PM2.5, PM1 and water-soluble metals in the ambient air

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Development of a “real-life” exposure system to ambient PM1 and PM2.5 particles for Wistar rats.

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Blood transcriptome analysis identified differentially expressed genes as candidate biomarkers in PM1 and PM2.5 groups.

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Pathway analysis revealed differentially regulated gene expression in inflammation signaling.

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Identification of candidate metals for possible correlation with the identified candidate genes leading to the development of AOPs.

Exposure to particulate matter (PM) is one of the most important environmental issues in Europe with major health impact. Various sizes of PM are suspended in the atmosphere and contributes to ambient air pollution. The current study aimed to explore the differential gene expression in blood, and the effect on the respective biological signaling pathways in Wistar rats, after exposure to PM2.5 and PM1 ambient air particles for an eight-week period. A control group was included with animals breathing non-filtered atmospheric air. In parallel, filtered PM2.5 and PM1 was collected in separate samplers. The results after whole genome microarray analysis showed 23 differentially expressed genes (DEGs) between control and PM2.5 group. In addition, pairwise comparison between control and PM1 group displayed 5635 DEGs linked to 69 biological pathways involved in inflammatory response, cell cycle and carcinogenicity. The smaller the size of the inhaled particles, the more gene alterations are triggered compared to non-filtered air group. More specifically, in inflammation signaling procedures differentially regulated gene expression was shown for interleukin-4 (IL-4), IL-7, IL-1, IL-5, IL-9, IL-6 and IL-2. We have identified that RASGFR1, TRIM65, TRIM33, PLEKHB1, CAR4, S100A8, S100A9, ALPL, NP4 and the PROK2 genes are potential targets for the development of adverse outcome pathways (AOPs) due to “real-life” exposure of Wistar rats. Particle measurements during the exposure period showed elevated concentrations of Fe, Mn and Zn in both PM1 and PM2.5 filter fractions, and of Cu in PM2.5. In addition, water-soluble concentration of metals showed significant differences between PM1 and PM2.5 fractions for V, Zn, As, Pb and Mn. In summary, in this study specific gene biomarkers of exposure to ambient air have been identified and heavy metals that are possibly linked to their altered regulation have been found. The results of this research will pave the way for the development of novel AOPs concerning the health effects of the environmental pollution.

CD4+ T Cell Defects in a Mulibrey Patient With Specific TRIM37 Mutations

Mulibrey (muscle-liver-brain-eye) syndrome (MUL) is an autosomal recessive disorder caused by mutations in the TRIpartite motif (TRIM)37 gene, encoding for TRIM37 a member of the TRIM E3 ubiquitin ligase protein family. MUL patients are characterized by growth retardation, dysmorphic features, and a wide range of abnormalities affecting different organs. However, T-cell abnormalities have not been observed in MUL subjects, to date. Here we described the immunological features of a MUL child carrying recently identified TRIM37 mutations, a 17q22 deletion of maternal origin combined with a TRIM37 variant of paternal origin. Here we found quantitative and functional defects in CD4⁺ T cells from this MUL case. Low levels of TRIM37 protein were specifically detected in CD4⁺ T cells of MUL patient and associated with their altered proliferation and cytokine production. Of note, both CD4⁺ and CD8⁺ T lymphocytes of MUL child displayed an effector memory phenotype compared with healthy children. This clinical case research highlighted the possible role of TRIM37 in the control of immune cell number and function, especially in CD4⁺ T cells. Finally, this study may contribute to the novel mechanistic studies aim of identifying, in depth, the role of the TRIM37 protein in the immune system.

The induction and function of the anti-inflammatory fate of TH17 cells

T_H17 cells exemplify environmental immune adaptation: they can acquire both a pathogenic and an anti-inflammatory fate. However, it is not known whether the anti-inflammatory fate is merely a vestigial trait, or whether it serves to preserve the integrity of the host tissues. Here we show that the capacity of T_H17 cells to acquire an anti-inflammatory fate is necessary to sustain immunological tolerance, yet it impairs immune protection against S. aureus. Additionally, we find that TGF-β signalling via Smad3/Smad4 is sufficient for the expression of the anti-inflammatory cytokine, IL-10, in T_H17 cells. Our data thus indicate a key function of T_H17 cell plasticity in maintaining immune homeostasis, and dissect the molecular mechanisms explaining the functional flexibility of T_H17 cells with regard to environmental changes.

CD4⁺ T helper cells producing IL-17A (T_H17 cells) can take on pathogenic or anti-inflammatory functions in context-specific manners. Here the authors show that the anti-inflammatory fate of T_H17 cells contributes, via TGF-β signaling and induction of IL-10, to host immune tolerance, but also simultaneously dampens protective immunity against S. aureus.

Tet2 and Tet3 in B cells are required to repress CD86 and prevent autoimmunity

A contribution of epigenetic modifications to B cell tolerance has been proposed but not directly tested. Here we report that deficiency of ten-eleven translocation (Tet) DNA demethylase family members Tet2 and Tet3 in B cells led to hyperactivation of B and T cells, autoantibody production and lupus-like disease in mice. Mechanistically, in the absence of Tet2 and Tet3, downregulation of CD86, which normally occurs following chronic exposure of self-reactive B cells to self-antigen, did not take place. The importance of dysregulated CD86 expression in Tet2- and Tet3-deficient B cells was further demonstrated by the restriction, albeit not complete, on aberrant T and B cell activation following anti-CD86 blockade. Tet2- and Tet3-deficient B cells had decreased accumulation of histone deacetylase 1 (HDAC1) and HDAC2 at the Cd86 locus. Thus, our findings suggest that Tet2- and Tet3-mediated chromatin modification participates in repression of CD86 on chronically stimulated self-reactive B cells, which contributes, at least in part, to preventing autoimmunity.

TRIM33 prevents pulmonary fibrosis by impairing TGF-β1 signalling

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a devastating disease characterised by myofibroblast proliferation and abnormal extracellular matrix accumulation in the lungs. Transforming growth factor (TGF)-β1 initiates key profibrotic signalling involving the SMAD pathway and the small heat shock protein B5 (HSPB5). Tripartite motif-containing 33 (TRIM33) has been reported to negatively regulate TGF-β/SMAD signalling, but its role in fibrogenesis remains unknown. The objective of this study was to elucidate the role of TRIM33 in IPF.

METHODS

TRIM33 expression was assessed in the lungs of IPF patients and rodent fibrosis models. Bone marrow-derived macrophages (BMDM), primary lung fibroblasts and 3D lung tissue slices were isolated from Trim33-floxed mice and cultured with TGF-β1 or bleomycin (BLM). Trim33 expression was then suppressed by adenovirus Cre recombinase (AdCre). Pulmonary fibrosis was evaluated in haematopoietic-specific Trim33 knockout mice and in Trim33-floxed mice that received AdCre and BLM intratracheally.

RESULTS

TRIM33 was overexpressed in alveolar macrophages and fibroblasts in IPF patients and rodent fibrotic lungs. Trim33 inhibition in BMDM increased TGF-β1 secretion upon BLM treatment. Haematopoietic-specific Trim33 knockout sensitised mice to BLM-induced fibrosis. In primary lung fibroblasts and 3D lung tissue slices, Trim33 deficiency increased expression of genes downstream of TGF-β1. In mice, AdCre-Trim33 inhibition worsened BLM-induced fibrosis. In vitro, HSPB5 was able to bind directly to TRIM33, thereby diminishing its protein level and TRIM33/SMAD4 interaction.

CONCLUSION

Our results demonstrate a key role of TRIM33 as a negative regulator of lung fibrosis. Since TRIM33 directly associates with HSPB5, which impairs its activity, inhibitors of TRIM33/HSPB5 interaction may be of interest in the treatment of IPF.

Emerging RNA-binding roles in the TRIM family of ubiquitin ligases

TRIM proteins constitute a large, diverse and ancient protein family which play a key role in processes including cellular differentiation, autophagy, apoptosis, DNA repair, and tumour suppression. Mostly known and studied through the lens of their ubiquitination activity as E3 ligases, it has recently emerged that many of these proteins are involved in direct RNA binding through their NHL or PRY/SPRY domains. We summarise the current knowledge concerning the mechanism of RNA binding by TRIM proteins and its biological role. We discuss how RNA-binding relates to their previously described functions such as E3 ubiquitin ligase activity, and we will consider the potential role of enrichment in membrane-less organelles.

The Fate of Th17 Cells is Shaped by Epigenetic Modifications and Remodeled by the Tumor Microenvironment

Th17 cells represent a subset of CD4+ T cells characterized by the master transcription factor RORγt and the production of IL-17. Epigenetic modifications such as post-translational histone modifications and DNA methylation play a key role in Th17 cell differentiation and high plasticity. Th17 cells are highly recruited in many types of cancer and can be associated with good or bad prognosis. Here, we will review the remodeling of the epigenome induced by the tumor microenvironment, which may explain Th17 cell predominance. We will also discuss the promising treatment perspectives of molecules targeting epigenetic enzymes to remodel a Th17-enriched tumor microenvironment.

Molecular switches for regulating the differentiation of inflammatory and IL-10-producing anti-inflammatory T-helper cells

CD4 T-helper (Th) cells secret a variety of inflammatory cytokines and play critical roles in host defense against invading foreign pathogens. On the other hand, uncontrolled inflammatory responses mediated by Th cells may result in tissue damage and inflammatory disorders including autoimmune and allergic diseases. Thus, the induction of anti-inflammatory cytokine expression becomes an important "brake" to repress and/or terminate aberrant and/or unnecessary immune responses. Interleukin-10 (IL-10) is one of the most important anti-inflammatory cytokines to limit inflammatory Th cells and immunopathology and to maintain tissue homeostasis. Many studies have indicated that Th cells can be a major source of IL-10 under specific conditions both in mouse and human and that extracellular signals and cell intrinsic molecular switches are required to turn on and off Il10 expression in different Th cells. In this review, we will highlight the recent findings that have enhanced our understanding on the mechanisms of IL-10 induction in distinct Th-cell subsets, including Th1, Th2, and Th17 cells, as well as the importance of these IL-10-producing anti-inflammatory Th cells in immunity and inflammation.

Molecular mechanisms of T helper 17 cell differentiation: Emerging roles for transcription cofactors

T helper 17 (Th17) cells, characterized by secretion of IL-17 and IL-17F, are a specialized CD4⁺ effector T cell lineage that not only facilitates host defense against pathogen infection and maintenance of mucosal barrier, but also potently induces tissue inflammation and autoimmune diseases. Since its discovery in 2005, the developmental program of Th17 cells has been characterized, which involves a number of key cytokines, transcription factors and multiple layers of epigenetic modifications. However, how these mechanisms integrate into the complex regulatory network in Th17 cells has not been well defined. Emerging evidences have revealed essential roles of cofactors in controlling chromosome accessibilities and activities of Th17-specific transcription factors. Moreover, cofactors also act as critical signaling integrators to coordinate multiple signaling pathways and transcriptional programs. Deficiency or dysregulation of these cofactors results in defects in Th17 responses and induction of associated autoimmune diseases. Our lab has recently reported several important cofactors in Th17 cells. Here we summarize our findings regarding this new scenario of developmental regulation of Th17 cells. These findings may benefit the development of innovative strategies to treat autoimmune diseases.

H3K18ac Primes Mesendodermal Differentiation upon Nodal Signaling

Cellular responses to transforming growth factor β (TGF-β) depend on cell context. Here, we explored how TGF-β/nodal signaling crosstalks with the epigenome to promote mesendodermal differentiation. We find that expression of a group of mesendodermal genes depends on both TRIM33 and nodal signaling in embryoid bodies (EBs) but not in embryonic stem cells (ESCs). Only in EBs, TRIM33 binds these genes in the presence of expanded H3K18ac marks. Furthermore, the H3K18ac landscape at mesendodermal genes promotes TRIM33 recruitment. We reveal that HDAC1 binds to active gene promoters and interferes with TRIM33 recruitment to mesendodermal gene promoters. However, the TRIM33-interacting protein p300 deposits H3K18ac and further enhances TRIM33 recruitment. ATAC-seq data demonstrate that TRIM33 primes mesendodermal genes for activation by maintaining chromatin accessibility at their regulatory regions. Altogether, our study suggests that HDAC1 and p300 are key factors linking the epigenome through TRIM33 to the cell context-dependent nodal response during mesendodermal differentiation.

The Roles of TIF1γ in Cancer

Transcriptional intermediary factor 1 γ (TIF1γ), also known as TRIM33, RFG7, PTC7, or Ectodermin, is an E3 ubiquitin-ligase family member with a ring-box-coiled-coil region. It can regulate TGF-β/Smad signaling in two different ways in different cellular contexts. On one hand, TIF1γ can monoubiquitinate Smad4 to inhibit the formation of Smad2/3/4 nuclear complexes. On the other hand, TIF1γ can function as a cofactor of phosphorylated (p)-Smad2/3, competing with Smad4 to inhibit the formation of the Smad2/3/4 complex. In addition, TIF1γ has been reported to play a role in transcription elongation, cellular differentiation, embryonic development, and mitosis. As transforming growth factor-β (TGF-β) superfamily signaling plays an important role in the occurrence and development of cancer, and TIF1γ was reported to be involved in the regulation of TGF-β superfamily signaling, studies on TIF1γ during the last decade have focused on its role in the development of cancer. However, TIF1γ can function either as a tumor suppressor or promoter in different cellular contexts, yet there are few reviews focusing on the roles of TIF1γ in cancer. Hence, in this paper we systematically review and discuss the roles of TIF1γ in cancer. Firstly, we review the biological features, the regulatory mechanisms and the related signaling pathways of TIF1γ. Next, we illustrate the roles of TIF1γ in different tumors. We then provide a tentative hypothesis that explains the dual roles of TIF1 γ in cancer. Finally, we provide our viewpoint regarding the future developments of cancer research focusing on TIF1γ, especially in relation to the effects of TIF1γ on tumoral immunity.

TGF-β signaling in cell fate control and cancer

Members of the transforming growth factor-β (TGF-β) family regulate cell fate decisions during early embryonic development and tissue homeostasis in the adult. Deregulation of TGF-β family signaling contributes to developmental anomalies, fibrotic disorders, tumorigenesis and immune diseases. TGF-β exerts a wide spectrum of cellular functions by activating canonical (SMAD-dependent) or non-canonical (SMAD-independent) pathways in a cell type-specific and context-dependent manner. Here, we focus on recent advances in the understanding of the mechanisms and functions of SMAD and non-SMAD pathways in physiology and pathology.

Up-regulation of TIF1γ by valproic acid inhibits the epithelial mesenchymal transition in prostate carcinoma through TGF-β/Smad signaling pathway

Valproic acid (VPA), one of the histone deacetylase inhibitors, can suppress prostate cancer (PCa) cells epithelial mesenchymal transition (EMT). Transcriptional intermediary factor 1γ (TIF1γ) which is a vital protein molecule that possesses ubiquitination enzyme activity, can mediate TGF-β induced EMT. We aimed to investigate the detailed mechanism between VPA and EMT occurrence in PCa cells to clarify the potential mechanism of TIF1γ involved. In our vitro experiments, we first investigated the effect of VPA on the expression TIF1γ. After TIF1γ was knockdown or overexpressed by related lentivirus, EMT of PCa cells were assessed. When TIF1γ knockdown or overexpress stable cell line were established, cells were treated with additional VPA, EMT index were detected and functional experiments were also conducted to confirm whether VPA inhibited EMT of PCa cells via TIF1γ. The mono-ubiquitination of Smad4 was analyzed simultaneously. In vivo, mice were facilitated with PC3 cells or TIF1γ related knockdown or overexpress virus transfected PC3 cells with or without VPA administration. Results showed that in vitro VPA can increase the expression of TIF1γ and also induce the increase expression of E-cadherin, and the decrease of N-cadherin and vimentin. Knocking down of TIF1γ can effectively block the effect of VPA on EMT and metastasis while overexpression of TIF1γ can strengthen its role. In vivo VPA also showed its anti-growth effect including tumor growth and EMT mediated by TIF1γ coincide with in vitro experiments. In conclusion, VPA inhibits the EMT in PCa cells via up-regulating the expression of TIF1γ and the mono-ubiquitination Smad4. VPA could serve as a promising agent in PCa treatment, with new strategies based on its diverse effects on posttranscriptional regulation.

Trim33 is required for appropriate development of pre-cardiogenic mesoderm

Congenital cardiac malformations are among the most common birth defects in humans. Here we show that Trim33, a member of the Tif1 subfamily of tripartite domain containing transcriptional cofactors, is required for appropriate differentiation of the pre-cardiogenic mesoderm during a narrow time window in late gastrulation. While mesoderm-specific Trim33 mutants did not display noticeable phenotypes, epiblast-specific Trim33 mutant embryos developed ventricular septal defects, showed sparse trabeculation and abnormally thin compact myocardium, and died as a result of cardiac failure during late gestation. Differentiating embryoid bodies deficient in Trim33 showed an enrichment of gene sets associated with cardiac differentiation and contractility, while the total number of cardiac precursor cells was reduced. Concordantly, cardiac progenitor cell proliferation was reduced in Trim33-deficient embryos. ChIP-Seq performed using antibodies against Trim33 in differentiating embryoid bodies revealed more than 4000 peaks, which were significantly enriched close to genes implicated in stem cell maintenance and mesoderm development. Nearly half of the Trim33 peaks overlapped with binding sites of the Ctcf insulator protein. Our results suggest that Trim33 is required for appropriate differentiation of precardiogenic mesoderm during late gastrulation and that it will likely mediate some of its functions via multi-protein complexes, many of which include the chromatin architectural and insulator protein Ctcf.

Cellular TRIM33 restrains HIV-1 infection by targeting viral integrase for proteasomal degradation

Productive HIV-1 replication requires viral integrase (IN), which catalyzes integration of the viral genome into the host cell DNA. IN, however, is short lived and is rapidly degraded by the host ubiquitin-proteasome system. To identify the cellular factors responsible for HIV-1 IN degradation, we performed a targeted RNAi screen using a library of siRNAs against all components of the ubiquitin-conjugation machinery using high-content microscopy. Here we report that the E3 RING ligase TRIM33 is a major determinant of HIV-1 IN stability. CD4-positive cells with TRIM33 knock down show increased HIV-1 replication and proviral DNA formation, while those overexpressing the factor display opposite effects. Knock down of TRIM33 reverts the phenotype of an HIV-1 molecular clone carrying substitution of IN serine 57 to alanine, a mutation known to impair viral DNA integration. Thus, TRIM33 acts as a cellular factor restricting HIV-1 infection by preventing provirus formation.

HIV-1 integration into host DNA is mediated by the viral integrase (IN). Here, using siRNA screen and high-content microscopy, the authors identify the host E3 RING ligase TRIM33 to affect IN stability and show that TRIM33 prevents viral integration by triggering IN proteasome-mediated degradation.

Bromodomain protein inhibition: a novel therapeutic strategy in rheumatic diseases

The reading of acetylation marks on histones by bromodomain (BRD) proteins is a key event in transcriptional activation. Small molecule inhibitors targeting bromodomain and extra-terminal (BET) proteins compete for binding to acetylated histones. They have strong anti-inflammatory properties and exhibit encouraging effects in different cell types in vitro and in animal models resembling rheumatic diseases in vivo. Furthermore, recent studies that focus on BRD proteins beyond BET family members are discussed.

TRIMming TGF-β signals in Th17 cells

The precise downstream mediators of TGF-β signaling in Th17 and T reg cells remain unclear. In this issue of JEM, Tanaka et al. report that Trim33 transduces TGF-β signals in Th17 cells to generate an optimal proinflammatory cytokine profile.