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In the past few decades, advances in the outcomes of patients suffering from pancreatic ductal adenocarcinoma (PDAC) have lagged behind these gained in the treatment of many other malignancies. Although the pivotal role of the SUMO pathway in PDAC has been illustrated, the underlying molecule drivers have yet to be fully elucidated. In the present study, we identified SENP3 as a potential suppressor of PDAC progression through an in vivo metastatic model. Further studies revealed that SENP3 inhibited PDAC invasion in a SUMO system dependent fashion. Mechanistically, SENP3 interacted with DKC1 and, as such, catalyzed the deSUMOylation of DKC1, which accepted SUMO3 modifiers at three lysine residues. SENP3-mediated deSUMOylation caused DKC1 instability and disruption of the interaction between snoRNP proteins, which contributed to the impaired migration ability of PDAC. Indeed, overexpression of DKC1 abated the anti-metastasis effect of SENP3, and DKC1 was elevated in PDAC specimens and associated with a poor prognosis in PDAC patients. Collectively, our findings shed light on the essential role of SENP3/DKC1 axis in the progression of PDAC.

Supplementary Figure S1. Expression and activation of YAP and other Hippo Pathway factors in CD4+ T cell subsets; Supplementary Figure S2. Characterization of the baseline immune profile of T cell-specific YAP-deficient mice; Supplementary Figure S3. Haematoxylin and eosin staining of lung, kidney, liver, small intestine and stomach sections from 21-day-old wild-type and YAPcKO mice; Supplementary Figure S4. The effect on iTreg generation under optimal TGFβ concentration; Supplementary Figure S5. Treg-specific YAP deficiency slows the growth of implanted MC38-colon tumors and boosts anti-tumor immunity; Supplementary Figure S6. Treg-specific YAP deficiency slows the growth of implanted EL4 thymomas and boosts anti-tumor immunity; Supplementary Figure S7. The effect of YAP inhibition monotherapy and combinational immunotherapy treatments on the immune constituents of the tumor microenvironment; Supplementary Figure S8. Correlation of gene expression in stimulated wild-type and YAP cKO derived Tregs; Supplementary Figure S9. Both Activin A and its receptor (ACVR1c) are upregulated during the course of iTreg differentiation; Supplementary Figure S10. Effect of AcVR1c deficiency on iTreg differentiation; Supplementary Figure S11. Supplemental Activin fails to rescue iTreg generation when SMAD2/3 levels are lacking; Supplementary Figure S12. Effects of GM-Vac and Anti-Activin treatment on B16 tumor progression in Wild Type and AcVR1c KO mice; Supplementary Figure S13. A model for YAP-mediated TGFβ/SMAD signaling enhancement

Regulatory T cells (Treg) are critical for maintaining self-tolerance and immune homeostasis, but their suppressive function can impede effective antitumor immune responses. FOXP3 is a transcription factor expressed in Tregs that is required for their function. However, the pathways and microenvironmental cues governing FOXP3 expression and Treg function are not completely understood. Herein, we report that YAP, a coactivator of the Hippo pathway, is highly expressed in Tregs and bolsters FOXP3 expression and Treg function in vitro and in vivo. This potentiation stemmed from YAP-dependent upregulation of activin signaling, which amplifies TGFβ/SMAD activation in Tregs. YAP deficiency resulted in dysfunctional Tregs unable to suppress antitumor immunity or promote tumor growth in mice. Chemical YAP antagonism and knockout or blockade of the YAP-regulated activin receptor similarly improved antitumor immunity. Thus, we identify YAP as an unexpected amplifier of a Treg-reinforcing pathway with significant potential as an anticancer immunotherapeutic target.Significance: Tregs suppress antitumor immunity, and pathways supporting their function can be novel immunotherapy targets. Here, the selective expression of YAP by Tregs, its importance for their function, and its unexpected enhancement of pro-Treg Activin/SMAD signaling are reported, as are validations of potential cancer-fighting antagonists of YAP and its regulatory targets. Cancer Discov; 8(8); 1026–43. ©2018 AACR.This article is highlighted in the In This Issue feature, p. 899

Pancreatic ductal adenocarcinoma (PDAC) is a highly fatal malignancy with extremely poor prognosis. Gemcitabine resistance is a major challenge in the treatment of PDAC. Here, we showed that LINC00460 was associated with the response to gemcitabine both in PDAC patients and PDAC-PDX. After knocking down LINC00460 in PDAC tumor cells, results of RNA sequencing followed by gene ontology analysis indicated that LINC00460 influenced the activity of growth factors and modified the extracellular matrix. FISH showed that LINC00460 is mostly located in the cytoplasm. Results of RNA pull-down, LC-MS/MS, RIP, and immunoblotting confirmed that LINC00460 could directly bind to PDAP1. Furthermore, we demonstrated that LINC00460 mediated the cellular communication of PDAC tumor cells and CAFs by PDAP1/PDGFA/PDGFR signaling pathway and regulated the gemcitabine-resistance function of CAFs, which could be reversed by treatment with a PDGFR inhibitor (crenolanib). PDAC-PDX tumors with lower expression of LINC00460 showed a better response to gemcitabine plus crenolanib treatment. Our finding supported the application of LINC00460 in precision medicine that uses gemcitabine plus crenolanib to treat PDAC with low expression of LINC00460.

Neutrophil infiltration plays an important role in the initial phase of hepatic ischemia and reperfusion injury (HIRI). Despite many different key molecules that have been reported to meditate neutrophil trafficking in HIRI, the mechanism of this process has not been fully elucidated. In this study, we found that Carabin deficiency in myeloid cells (LysMCre : Carabinfl/fl) aggravated IRI-induced hepatic injury and apoptosis through increasing the infiltration of CD11b

BACKGROUND: Cancer-associated fibroblasts (CAFs) are a major component of hepatocellular carcinoma (HCC) stroma that are critically involved in HCC cancer chemoresistance, but the mechanism has not been elucidated. Previous studies have reported CD73 exerted an immunosuppressive function in cancer. Here, we explored the mechanism by which CAFs regulates CD73(+) HCC cells and clarified whether CAFs promote chemoresistance of CD73(+) cells. METHODS: We used the co-culture method to study the relationship between CAFs and HCC cells. Immunohistochemistry was applied to evaluate the correlation between α-smooth-muscle actin (α-SMA) and CD73. CD73 mRNA and protein were determined by real-time polymerase chain reaction (RT-PCR) and western blotting, and hepatocyte growth factor (HGF) was assayed by enzyme-linked immunosorbent assay (ELISA). Western blotting was used to explore the regulated pathway of CD73(+) HCC. We then knocked down CD73 in cells, and then assessed the effect of CD73 on the apoptosis by flow cytometry. Finally, a sphere formation assay was applied to investigate the stemness of cancer cells, and xenograft tumors in nude mice were built to investigate the tumorigenicity. RESULTS: We found that the proportion of CAFs was positively correlated with CD73 expression in HCC cells. Mechanistically, c-Met and the MEK-ERK1/2 pathway were activated by HGF from CAFs which upregulated CD73 expression in HCC cells. Also, we found that CD73 promote sorafenib and cisplatin resistance in HCC, and CD73(+) HCC cells indicated the higher capability of tumorigenicity compared to CD73(−) HCC cells in vivo. Furthermore, HGF further enhanced the chemoresistant characteristics of CD73(+) tumor cells. CONCLUSIONS: Our findings collectively suggest that CD73 is a vital HCC-chemoresistance force controlled by cross-talking between CAFs and HCC cells, thereby establishing CD73 as a potential new therapeutic target for HCC.

Rejection after organ transplantation is a cause of graft failure. Effectively reducing rejection and inducing tolerance is a challenge in the field of transplantation immunology. The liver, as an immunologically privileged organ, has high rates of spontaneous and operational tolerance after transplantation, allowing it to maintain its normal function for long periods. Although modern immunosuppression regimens have serious toxicity and side effects, it is very risky to discontinue immunosuppression regimens blindly. A more effective treatment to induce immune tolerance is the most sought-after goal in transplant medicine. Tregs have been shown to play a pivotal role in the regulation of immune balance, and infusion of Tregs can also effectively prevent rejection and cure autoimmune diseases without significant side effects. Given the immune characteristics of the liver, the correct use of Tregs can more effectively induce the occurrence of operational tolerance for liver transplants than for other organ transplants. This review mainly summarizes the latest research advances regarding the characteristics of the hepatic immune microenvironment, operational tolerance, Treg generation in vitro, and the application of Tregs in liver transplantation. It is hoped that this review will provide a deeper understanding of Tregs as the most effective treatment to induce and maintain operational tolerance after liver transplantation.

Regulatory T cells (Treg) are critical for maintaining self-tolerance and immune homeostasis, but their suppressive function can impede effective antitumor immune responses. FOXP3 is a transcription factor expressed in Tregs that is required for their function. However, the pathways and microenvironmental cues governing FOXP3 expression and Treg function are not completely understood. Herein, we report that YAP, a coactivator of the Hippo pathway, is highly expressed in Tregs and bolsters FOXP3 expression and Treg function in vitro and in vivo. This potentiation stemmed from YAP-dependent upregulation of activin signaling, which amplifies TGFβ/SMAD activation in Tregs. YAP deficiency resulted in dysfunctional Tregs unable to suppress antitumor immunity or promote tumor growth in mice. Chemical YAP antagonism and knockout or blockade of the YAP-regulated activin receptor similarly improved antitumor immunity. Thus, we identify YAP as an unexpected amplifier of a Treg-reinforcing pathway with significant potential as an anticancer immunotherapeutic target. Significance: Tregs suppress antitumor immunity, and pathways supporting their function can be novel immunotherapy targets. Here, the selective expression of YAP by Tregs, its importance for their function, and its unexpected enhancement of pro-Treg Activin/SMAD signaling are reported, as are validations of potential cancer-fighting antagonists of YAP and its regulatory targets. Cancer Discov; 8(8); 1026–43. ©2018 AACR. This article is highlighted in the In This Issue feature, p. 899

Regulatory T cells (Tregs) are crucial mediators of immune control. The characteristic gene expression and suppressive functions of Tregs depend considerably on the stable expression and activity of the transcription factor FOXP3. Transcriptional regulation of the Foxp3 gene has been studied in depth, but both the expression and function of this factor are also modulated at the protein level. However, the molecular players involved in posttranslational FOXP3 regulation are just beginning to be elucidated. Here, we found that TRAF6‐deficient Tregs were dysfunctional in vivo ; mice with Treg‐restricted deletion of TRAF6 were resistant to implanted tumors and displayed enhanced anti‐tumor immunity. We further determined that FOXP3 undergoes K63‐linked ubiquitination at lysine 262 mediated by the E3 ligase TRAF6. In the absence of TRAF6 activity or upon mutation of the ubiquitination site, FOXP3 displayed aberrant, perinuclear accumulation and disrupted regulatory function. Thus, K63‐linked ubiquitination by TRAF6 ensures proper localization of FOXP3 and facilitates the transcription factor9s gene‐regulating activity in Tregs. These results implicate TRAF6 as a key posttranslational, Treg‐stabilizing regulator that may be targeted in novel tolerance‐breaking therapies.

Human gingival tissue-derived mesenchymal stem cells (GMSCs) present an accessible source of mesenchymal stem cells (MSCs) for treating autoimmune diseases. Here we show that human GMSCs can prevent and treat acute graft-versus-host disease (GVHD) in two different mouse models. Our results indicate that besides exhibiting suppressive function in vitro and in vivo, GMSCs may also regulate the conversion of Tregs to Th1 and/or Th17-like cells, as well as stabilize Foxp3 expression. Furthermore, GMSC-mediated prevention of acute GVHD was dependent on CD39 signaling that play an important role in the function and stability of Tregs. Finally, we also observed stronger protective ability of GMSCs with greater expansion ability compared with BMSCs or ASCs. These results indicate that human GMSCs have the potential to be used to treat GVHD.

Regulatory T cells (Tregs) play a critical role in sustaining immune tolerance and maintaining immune balance to alloantigen after transplatation. However, the functions of peripheral Tregs in different organs have not been fully characterized. Here, we showed that spleen-derived Tregs exhibited higher expression of Foxp3, greater suppressive capacity, and lower levels of IL-17A secretion than lymph node-derived Tregs in vitro in the presence or absence of inflammatory cytokines, such as IL-6. We found a higher percentage of CD25(bright) Tregs among spleen-derived Tregs than among lymph node-derived Tregs. Additionally, in vivo experiments demonstrated that adoptive transfer of spleen-derived Tregs, but not lymph node-derived Tregs, alleviated ischemia-reperfusion injury. These results reveal novel functions of Tregs derived from peripheral organs. In particular, spleen-derived Tregs, primarily consisting of CD25(bright) cells, may provide a more significant contribution to the suppression of immune-mediated autoimmune and inflammatory disease.

Autoimmune diseases are characterized by an imbalance between regulatory T cells and effector T-cell subsets, such as Th1 and Th17 cells. Studies have confirmed that natural CD4+Foxp3+ Tregs were unstable and dysfunctional in the presence of pro-inflammatory cytokines. In the current study, human CD39hi Tregs and CD39low Tregs were sorted from Tregs in vitro after 7 days of expansion. The functions of both Treg subsets were investigated under inflammatory conditions in vitro and in vivo. In the presence of IL-1β and IL-6, cultured CD4+CD39hi Tregs maintained stable forkhead box protein 3 expression, whereas CD4+CD39low Tregs lost Foxp3 expression and trans-differentiated into Th1 or Th17 cells. Decreased IL-1βR and IL-6R expression on the CD39hi Tregs was the primary mechanism responsible for Treg stability. In addition, reduced activation of downstream molecules, such as STAT1 and STAT3, through the modulation of CpG demethylation played an important role. Finally, human CD4+CD39hi Tregs but not CD4+CD39low Tregs protected against xenograft versus host disease in model mice. These results strongly implied the physiological importance of CD39 expression and suggested that manipulation of CD39hi Tregs might represent a novel strategy for the treatment of autoimmune diseases.

Regulatory T (Treg) cells are important in maintaining self-tolerance and immune homeostasis. The Treg cell transcription factor Foxp3 works in concert with other co-regulatory molecules, including Eos, to determine the transcriptional signature and characteristic suppressive phenotype of Treg cells. Here, we report that the inflammatory cytokine interleukin-6 (IL-6) actively repressed Eos expression through microRNA-17 (miR-17). miR-17 expression increased in Treg cells in the presence of IL-6, and its expression negatively correlated with that of Eos. Treg cell suppressive activity was diminished upon overexpression of miR-17 in vitro and in vivo, which was mitigated upon co-expression of an Eos mutant lacking miR-17 target sites. Also, RNAi of miR-17 resulted in enhanced suppressive activity. Ectopic expression of miR-17 imparted effector-T-cell-like characteristics to Treg cells via the de-repression of genes encoding effector cytokines. Thus, miR-17 provides a potent layer of Treg cell control through targeting Eos and additional Foxp3 co-regulators.

Tumors escape immune attacks via various mechanisms, among which activation of regulatory pathways in effector immune cells and recruitment of immunosuppressive cells are usually employed. Traf6 is a member of the family of tumor necrosis factor receptor-associated factors and involved in many signaling pathways. While it plays important roles in both tumor biology and immune system, the potential therapeutic role of Traf6 in tumor immunotherapy hasn't ever been assessed. Here, we confirmed the anti-tumor effect of Traf6 inhibitor in Hepa1-6 tumor model. Flow cytometry-based analysis revealed that T cell-mediated antitumor immunity was provoked and the infiltration of Treg cells was restrained when treated with Traf6 inhibitor. Via an in vivo migration assay, we found that Traf6 inhibitor decreased the population of intratumor Tregs by impeding the migration of Tregs towards tumor. Finally, we demonstrated that combination of Traf6 inhibitor and PD-1 blockade could receive a better antitumor efficiency. These results implicated that Traf6 inhibitor could serve as a supplement for immune checkpoint therapy.

Regulatory T cells (Treg) are crucial mediators of immune control. The characteristic gene expression and suppressive function of Treg depend considerably on the stable expression and activity of the transcription factor Foxp3. While transcriptional regulation of the Foxp3 gene has been studied in depth, both the expression and function of Foxp3 are also modulated at the protein level. However, the molecular players involved in posttranslational Foxp3 regulation are just beginning to be elucidated. Here we found TRAF6-deficient Tregs were dysfunctional in vivo; mice with Treg-restricted deletion of TRAF6 were resistant to B16 melanomas and displayed enhanced anti-tumor immunity. We further determined that Foxp3 undergoes lysine-63 chain (K63) ubiquitination at lysine 262 mediated by the E3 ligase TRAF6. When deprived of TRAF6 activity or rendered insensitive to K63 ubiquitination, Foxp3 displayed aberrant, perinuclear accumulation, disrupted function. Thus, Foxp3 ubiquitination by TRAF6 ensures proper localization of Foxp3 and facilitates Foxp3’s gene-regulating activity in Tregs. These results implicate TRAF6 as a key posttranslational, Treg-stabilizing force that may be targeted in novel tolerance-breaking therapies.

Activating transcription factor 3 (ATF3) is a stress-induced transcription factor that plays important roles in regulating immune and metabolic homeostasis. Activation of the mechanistic target of rapamycin (mTOR) and hypoxia-inducible factor (HIF) transcription factors are crucial for the regulation of immune cell function. Here, we investigated the mechanism by which the ATF3/mTOR/HIF-1 axis regulates immune responses in a liver ischemia/reperfusion injury (IRI) model. Deletion of ATF3 exacerbated liver damage, as evidenced by increased levels of serum ALT, intrahepatic macrophage/neutrophil trafficking, hepatocellular apoptosis, and the upregulation of pro-inflammatory mediators. ATF3 deficiency promoted mTOR and p70S6K phosphorylation, activated high mobility group box 1 (HMGB1) and TLR4, inhibited prolyl-hydroxylase 1 (PHD1), and increased HIF-1α activity, leading to Foxp3 downregulation and RORγt and IL-17A upregulation in IRI livers. Blocking mTOR or p70S6K in ATF3 knockout (KO) mice or bone marrow-derived macrophages (BMMs) downregulated HMGB1, TLR4, and HIF-1α and upregulated PHD1, increasing Foxp3 and decreasing IL-17A levels in vitro. Silencing of HIF-1α in ATF3 KO mice ameliorated IRI-induced liver damage in parallel with the downregulation of IL-17A in ATF3-deficient mice. These findings demonstrated that ATF3 deficiency activated mTOR/p70S6K/HIF-1α signaling, which was crucial for the modulation of TLR4-driven inflammatory responses and T cell development. The present study provides potential therapeutic targets for the treatment of liver IRI followed by liver transplantation.

Cytotoxic chemotherapy is frequently used in patients with triple-negative breast cancer (TNBC). Although patients initially respond to the treatment, the cancer often comes back and kills the patient. Recent studies have demonstrated that cancer cells express genes that protect them from killing by immune cells, but the stimulus that prompts this response is unknown. We show that when TNBC cells are treated with chemotherapy, the surviving cells turn on genes that enable them to escape killing by the immune system. We identify hypoxia-inducible factors (HIFs), which are known to promote metastasis of TNBC, as responsible for this countertherapeutic effect. We show that coadministration of an HIF inhibitor with chemotherapy blocks the ability of surviving TNBC cells to evade the immune system.

Triple-negative breast cancer (TNBC) is treated with cytotoxic chemotherapy and is often characterized by early relapse and metastasis. To form a secondary (recurrent and/or metastatic) tumor, a breast cancer cell must evade the innate and adaptive immune systems. CD47 enables cancer cells to evade killing by macrophages, whereas CD73 and PDL1 mediate independent mechanisms of evasion of cytotoxic T lymphocytes. Here, we report that treatment of human or murine TNBC cells with carboplatin, doxorubicin, gemcitabine, or paclitaxel induces the coordinate transcriptional induction of CD47, CD73, and PDL1 mRNA and protein expression, leading to a marked increase in the percentage of CD47+CD73+PDL1+ breast cancer cells. Genetic or pharmacological inhibition of hypoxia-inducible factors (HIFs) blocked chemotherapy-induced enrichment of CD47+CD73+PDL1+ TNBC cells, which were also enriched in the absence of chemotherapy by incubation under hypoxic conditions, leading to T cell anergy or death. Treatment of mice with cytotoxic chemotherapy markedly increased the intratumoral ratio of regulatory/effector T cells, an effect that was abrogated by HIF inhibition. Our results delineate an HIF-dependent transcriptional mechanism contributing to TNBC progression and suggest that combining chemotherapy with an HIF inhibitor may prevent countertherapeutic induction of proteins that mediate evasion of innate and adaptive antitumor immunity.

Graft-versus-host disease (GVHD) is an intractable complication in transplant patients. Regulatory T cells (Tregs) have the ability to prevent GVHD and consist of two subsets: natural Tregs (nTregs) and induced Tregs (iTregs). In comparison to nTregs, iTregs originate in the periphery under certain conditions and show improved proliferative and suppressive abilities in an inflammatory milieu. All-trans retinoic acid (atRA) favors Treg expansion and FoxP3 expression in human Tregs. However, whether atRA can affect the function of iTregs from transplant patients remains inconclusive. Therefore, we sorted naïve T cells from liver transplant patients and cultured them in vitro. Further analyses were performed to assess the suppressive function of iTregs in vitro and in vivo. atRA favored expansion and forkhead box P3 expression in iTregs from transplant patients. In comparison to iTregs from healthy donors, iTregs from transplant patients showed decent suppressive abilities in vitro and in vivo. Our findings suggest that atRA can potentially improve the development and function of iTregs from transplant patients. Furthermore, our results provide novel insights into Treg therapy in GVHD clinical trials.

All-trans retinoic acid (atRA), the active derivative of vitamin A, has been shown to regulate Treg and T effector cell differentiation. However, the potential use of atRA as a treatment for acute graft-verse-host disease (aGVHD) has not been realized. Here we studied the ability of atRA to prevent and treat acute-GVHD in the B6-to-F1(D2B6F1) murine model. Our results showed that atRA consistently displayed a potent ability to control aGVHD development and reduce mortality by suppressing the expansion of donor T cells and inhibiting cytokine expression from donor CD8 cells. Interestingly, CD4(+)Foxp3(+) regulatory T cells were markedly increased in the spleens of atRA-treated mice. In vitro treatment with atRA inhibited T cell proliferation in a dose-dependent manner. Injection of an anti-IL-2 antibody impaired the protection by atRA in aGVHD. Therefore, these results strongly implicate atRA as a novel therapeutic strategy for controlling aGVHD progression and treating other inflammatory diseases.

Background/Aims: Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and has the third highest mortality rate among all cancers. MicroRNAs are a class of endogenous, single-stranded short noncoding RNAs. The purpose of this study was to study the role of microRNA-873 in HCC. Methods: The expression of miRNA-873 and tumor suppressor in lung cancer 1 (TSLC1) in HCC tissues and cell lines was detected by real-time quantitative RT-PCR (RT-qPCR) or western blot. A CCK-8 assay was used to examine cell proliferation; flow cytometry was used to assess the cell cycle; the Transwell migration assay was used to test for metastasis. Luciferase assays were performed to assess whether TSLC1 was a novel target of miRNA-873. Results: We showed that miRNA-873 was upregulated in HCC tissues and cell lines compared with the normal control. Knockdown of miRNA-873 inhibited the growth and metastasis of HepG2 and accelerated G1 phase arrest, while overexpression of miRNA-873 had the opposite effect. The dual-luciferase reporter assays revealed that TSLC1 was a novel target of miRNA-873. Further study showed that TSLC1 was decreased in HCC tissues and cell lines. There was a negative correlation between the expression levels of TSLC1 and miRNA-873. The effect of miRNA-873 overexpression was neutralized by TSLC1. We also found that miRNA-873 activated the PI3K/AKT/mTOR signaling pathway and promoted HCC. Conclusions: Our data demonstrated that miRNA-873 promoted HCC progression by targeting TSLC1 and provided a new target for the therapy of HCC.

Background: Regulatory B cells (Bregs) play an essential role in inflammation and transplant tolerance. Several studies have reported a decreased number of Bregs in renal transplant patients with graft rejection. However, little is known about their role in the liver alloresponse. Methods: To investigate whether the circulating Bregs have been associated with acute allograft rejection (AR) in liver transplantation patients, 19 patients receiving liver allografts from donation after cardiac death (DCD) donors were retrospectively studied. Results: The postoperative proportions of circulating CD19 + CD24 hi CD38 hi transitional Bregs (tBregs) and CD19 + CD24 hi CD27 + memory Bregs (mBregs) in patients diagnosed with AR (AR group) and other patients with stable allograft liver function (SF group) were evaluated using flow cytometry (FCM) analysis. Results showed that while no significant changes were found regarding both the tBreg and mBreg, proportions across all time points in the SF group, the AR group showed significantly decreased proportions of mBregs. All of the five AR patients responded fine to the treatments, and the proportions of mBregs increased significantly after anti-rejection therapies. In addition, AR was suspected in four recipients, but gradually they were diagnosed with hemolytic or obstructive jaundice and showed no decrease in the proportion of mBregs. Conclusions: For the first time, our results suggested the potential role of a decreased proportion of circulating mBregs in predicting AR in patients with post liver transplantation.

CD4(+)CD25(+)FoxP3(+) thymic-derived regulatory T cells (tTregs) are indispensable for maintaining immune system equilibrium. Adoptive transfer of tTregs is an effective means of suppressing graft-versus-host disease (GVHD) in murine models and in early human clinical trials. Tumor necrosis factor receptor-associated factor 6 (TRAF6), an ubiquitin-conjugating enzyme that mediates nuclear factor κB (NF-κB) activation, plays an essential role in modulating regulatory T cell survival and function. MicroRNAs (miRNAs) are noncoding RNAs, which mediate RNA silencing and posttranscriptional gene repression. By performing comprehensive TaqMan Low Density Array miRNA assays, we identified 10 miRNAs differentially regulated in human tTreg compared with control T cells. One candidate, miR-146b, is preferentially and highly expressed in human naive tTregs compared with naive CD4 T cells. miRNA prediction software revealed that TRAF6 was the one of the top 10 scored mRNAs involved tTreg function with the highest probability as a potential miR-146b target. Antagomir-mediated knockdown of miRNA-146b, but not another miRNA-146 family member (miRNA-146a), enhanced TRAF6 expression. TRAF6, in turn, increases NF-κB activation, which is essential for tTreg function as well as Foxp3 protein and antiapoptotic gene expression, and downregulates proapoptotic gene expression. miR-146b knockdown increased the nuclear localization and expression of genes regulated by NF-κB, which was associated with enhanced tTreg survival, proliferation, and suppressive function measured in vitro and in vivo. TRAF6 inhibition had the opposite effects. We conclude that an miR-146b-TRAF6-NF-κB-FoxP3 signaling pathway restrains regulatory T cell survival, proliferation, and suppressor function. In vitro exposure of human tTregs to miR-146b antagomirs can be exploited to improve the clinical efficacy of human adoptive tTreg transfer in a GVHD setting.

Background and aims Recently, a couple of the long noncoding RNAs (lncRNAs) have been proved to participate in hepatocellular carcinoma development and progression. However, their associations with liver cirrhosis have not been reported. In this study, we aimed to identify the affection of HULC on regulatory T cells (Tregs) differentiation in HBV-related liver cirrhosis. Methods Seven lncRNAs were chosen as candidate lncRNAs based on the association with liver disease. The candidate lncRNAs were validated by RT-qPCR. Additional flow cytometry of Tregs was performed in 34 HBV-related liver cirrhosis patients and 34 healthy volunteers. To investigate the function of HULC, HULC expression was modified by gene overexpression via lentivirus vector. RIP assay was performed further to validate the association between HULC and p18. Results Circulation Tregs and HULC were significantly up-regulated in plasma samples of HBV-related cirrhosis patients. In addition, overexpression of HULC by lentivirus vector elevated Treg frequency in vitro. Furthermore, RIP assay showed that HULC down-regulated the level of p18 directly. Conclusions We confirmed the effects of HULC on Tregs differentiation in HBV-related liver cirrhosis. In addition, it was proved that HULC regulates the function of Tregs through down-regulated the level of p18 directly.