Suppression of Type I Interferon Signaling in Myeloid Cells by Autoantibodies in Severe COVID-19 Patients

PURPOSE

Auto-antibodies (auto-abs) to type I interferons (IFNs) have been identified in patients with life-threatening coronavirus disease 2019 (COVID-19), suggesting that the presence of auto-abs may be a risk factor for disease severity. We therefore investigated the mechanism underlying COVID-19 exacerbation induced by auto-abs to type I IFNs.

METHODS

We evaluated plasma from 123 patients with COVID-19 to measure auto-abs to type I IFNs. We performed single-cell RNA sequencing (scRNA-seq) of peripheral blood mononuclear cells from the patients with auto-abs and conducted epitope mapping of the auto-abs.

RESULTS

Three of 19 severe and 4 of 42 critical COVID-19 patients had neutralizing auto-abs to type I IFNs. Patients with auto-abs to type I IFNs showed no characteristic clinical features. scRNA-seq from 38 patients with COVID-19 revealed that IFN signaling in conventional dendritic cells and canonical monocytes was attenuated, and SARS-CoV-2-specific BCR repertoires were decreased in patients with auto-abs. Furthermore, auto-abs to IFN-α2 from COVID-19 patients with auto-abs recognized characteristic epitopes of IFN-α2, which binds to the receptor.

CONCLUSION

Auto-abs to type I IFN found in COVID-19 patients inhibited IFN signaling in dendritic cells and monocytes by blocking the binding of type I IFN to its receptor. The failure to properly induce production of an antibody to SARS-CoV-2 may be a causative factor of COVID-19 severity.

Anti-Vα24Jα18 TCR Antibody Tunes iNKT Cell Responses to Target and Kill CD1d-negative Tumors in an FcγRII (CD32)-dependent Manner

Invariant natural killer T (iNKT) cells play an essential role in antitumor immunity by exerting cytotoxicity and producing massive amounts of cytokines. iNKT cells express invariant T-cell receptors (TCR) to recognize their cognate glycolipid antigens such as α-galactosylceramide (α-GalCer) presented on CD1d. We recently reported that iNKT cells recognize CD1d-negative leukemia cell line K562 in a TCR-dependent manner. However, it remains controversial how iNKT cells use TCRs to recognize and exhibit cytotoxic activity toward CD1d-negative tumors cells without CD1d restriction. Here, we report that iNKT cells exerted cytotoxicity toward K562 cells via a carried over anti-Vα24 TCR mAb from positive selection by magnetic bead sorting. We found that addition of the anti-Vα24Jα18 TCR mAb (6B11 mAb) rendered iNKT cells cytotoxic to K562 cells in an FcγRII (CD32)-dependent manner. Moreover, iNKT cells treated with 6B11 mAb became cytotoxic to other CD32+ cell lines (U937 and Daudi). In addition, iNKT cells treated with 6B11 mAb suppressed K562 cell growth in a murine xenograft model in vivo. These data suggest that anti-iNKT TCR mAb treatment of iNKT cells can be applied as a therapeutic strategy to treat CD32+ cancers such as leukemia, lymphoma, and lung cancer.

SIGNIFICANCE

Our findings unveiled that iNKT cells recognize and kill CD1d-negative target tumors via the anti-iNKT TCR mAb bound to CD32 at the tumor site, thereby bridging iNKT cells and CD1d-negative tumors. These findings shed light on the therapeutic potential of anti-iNKT TCR mAbs in NKT cell-based immunotherapy to treat CD1d-negative CD32+ cancers.

Long-term treatment outcomes in gastric cancer with oligometastasis

Aim

While surgery is essential for curative treatment of gastric cancer with oligometastasis, its target, timing, and possibility of combination with other treatments are unclear. We herein investigated the clinical course and long-term outcomes of gastric cancer with oligometastasis in the real world setting to determine the optimal therapeutic strategy.

Methods

The present study retrospectively analyzed 992 patients who received any treatment for metastatic or recurrent gastric adenocarcinoma at Tokyo Metropolitan Komagome Hospital between 2007 and 2019. Oligometastasis was defined as any one of the following: liver metastases (HEP) <3; lung metastases (PUL) <3; unilateral adrenal gland metastasis (ADR); para-aortic lymph node metastasis (PALN); or one, distant, lymph node metastasis, excluding the regional lymph nodes (LYM). Overall survival was compared by the characteristics and treatments for the oligometastasis, and univariate and multivariate analyses were used to identify the prognostic factors of overall survival.

Results

Ninety-seven patients (9.8%) with the following metastasis sites were enrolled: HEP (n = 27), PUL (n = 2), ADR (n = 3), PALN (n = 55), and LYM (n = 10). The median survival time of the cohort was 22.8 months, and the five-year overall survival rate was 28.4%. On multivariate analysis, chemotherapy for the initial treatment (hazard ratio [HR]: 0.438; p = 0.048), distal gastrectomy and/or metastasectomy (HR: 0.290; p = 0.001), and R0 resection (HR: 0.373; p = 0.005) were identified as independent, positive factors of overall survival.

Conclusion

The long-term outcomes of gastric cancer in patients with oligometastasis may improve if treatment is begun with chemotherapy rather than surgery.

Robotically assisted total gastrectomy for lymphadenopathy after long-term follow-up for multiple type 1 gastric neuroendocrine tumor (NET): a case report

BACKGROUND

Type 1 gastric neuroendrine tumor (NET) is usually associated with chronic atrophic gastritis and forms multiple lesions. While most cases of type 1 gastric NET are generally slowly growing, some develop regional lymph node metastases even after long-term dormancy.

CASE PRESENTATION

A 73-year-old male patient with a 32-year history of multiple gastric NET was being followed-up at the study center after endoscopic submucosal dissection (ESD) of a large gastric NET. A blood examination revealed high serum gastrin (> 3000 pg/ml). An endoscopic examination found atrophic mucosa and multiple, elevated lesions in the upper to lower stomach body. Computed tomography (CT) revealed regional lymphadenopathy in the greater omentum along the gastroepiploic artery. Robotically assisted total gastrectomy was performed with D2 lymphadenectomy and Roux-en-Y reconstruction. Pathological analysis revealed a large number of gastric NET (grade 1) with a maximum size of 4.5 mm invading the submucosal layer. A single lymph node metastasis was also detected pathologically at station #4d. The postoperative course was uneventful, and serum gastrin normalized postoperatively. At postoperative year 3, the patient has been doing well without any recurrences.

CONCLUSIONS

The present case of multiple gastric NET with a single regional lymph node metastasis at year 32 of follow-up was successfully treated with a robotically assisted total gastrectomy.

Acquired diaphragmatic hernia following a peritoneal biopsy for gastric cancer dissemination in the diaphragm: a case report

BACKGROUND

Acute diaphragmatic hernia is a life-threatening condition caused by prolapse of an abdominal organ into the thoracic cavity through a defect in the diaphragm. We present herein a case of acquired diaphragmatic hernia following a peritoneal biopsy for gastric cancer dissemination in the diaphragm.

CASE PRESENTATION

A 72-year-old, female patient presented with a complaint of acute abdomen 10 months after receiving a diagnosis of stage IV gastric cancer with peritoneal dissemination based on peritoneal biopsy findings during staging laparoscopy. Computed tomography demonstrated herniation of the small intestine into the thoracic cavity. Emergency surgery was performed, and a full-thickness diaphragmatic defect was found intraoperatively at the same location as the previous, peritoneal biopsy. The incarcerated small intestine was atraumatically repositioned into the abdominal cavity, and the defect was closed laparoscopically using an absorbable barbed suture.

CONCLUSIONS

Although complications of staging laparoscopy are extremely rare, excising disseminated nodules from the diaphragm carries the risk of diaphragmatic hernia. For this reason, avoiding excision is desirable unless a diaphragmatic biopsy is needed.

CD69 imposes tumor-specific CD8+ T-cell fate in tumor-draining lymph nodes

Tumor-specific CD8+ T cells play a pivotal role in anti-tumor immunity and are a key target of immunotherapeutic approaches. Intratumoral CD8+ T cells are heterogeneous; Tcf1+ stem-like CD8+ T cells give rise to their cytotoxic progeny - Tim-3+ terminally differentiated CD8+ T cells. However, where and how this differentiation process occurs has not been elucidated. We herein show that terminally differentiated CD8+ T cells can be generated within tumor-draining lymph nodes (TDLNs) and that CD69 expression on tumor-specific CD8+ T cells controls its differentiation process through regulating the expression of the transcription factor TOX. In TDLNs, CD69 deficiency diminished TOX expression in tumor-specific CD8+ T cells, and consequently promoted generation of functional terminally differentiated CD8+ T cells. Anti-CD69 administration promoted the generation of terminally differentiated CD8+ T cells, and the combined use of anti-CD69 and anti-PD-1 showed an efficient anti-tumor effect. Thus, CD69 is an attractive target for cancer immunotherapy that synergizes with immune checkpoint blockade.

Pathogenic helper T cells as the novel therapeutic targets for immune-mediated intractable diseases

Allergic diseases arise from a complex interplay between immune system and environmental factors. A link between the pathogenesis of allergic diseases and type 2 immune responses has become evident, with conventional and pathogenic type 2 helper T (Th2) cells involved in both. Recently, there has been a significant development in therapeutic agents for allergic diseases: IL-5 and IL-5 receptor antagonists, Janus kinase (JAK) inhibitors, and sublingual immunotherapy (SLIT). Mepolizumab, an IL-5, and Benralizumab, an IL-5 receptor antagonist, modulate eosinophilic inflammation mediated by IL-5-producing Th2 cells. Delgocitinib shows that JAK-associated signaling is essential for the inflammatory reaction in atopic dermatitis, one of the common allergic diseases. SLIT has a significant effect on allergic rhinitis by reducing pathogenic Th2 cell numbers. More recently, novel molecules that are involved in pathogenic Th2 cell-mediated allergic diseases have been identified. These include calcitonin gene-related peptide (CGRP), reactive oxygen species (ROS) scavenging machinery regulated by the Txnip-Nrf2-Blvrb axis, and myosin light chain 9 (Myl9), which interacts with CD69. This review provides an updated view of the recent research on treatment of allergic diseases and their cause: conventional and pathogenic Th2 cells.

Robotic distal gastrectomy with D2 lymphadenectomy for advanced gastric cancer with celiac-arterial anomaly (Adachi type VI, group 26): Case report

In gastric cancer surgery, some celiac-arterial anomalies are associated with a risk of anatomical misidentification and insufficient lymphadenectomy. We herein report a case of successful robotic distal gastrectomy with D2 lymphadenectomy based on preoperative, anatomical recognition using three-dimensional computed tomography (3D-CT) in a patient with advanced gastric cancer and a rare anomaly of the celiac artery. A 64-year-old, male patient was referred to our division with a diagnosis of advanced gastric cancer. The 3D-CT angiography demonstrated an Adachi type VI, group 26 celiac-arterial anomaly, in which the common hepatic artery branched from the left gastric artery but was widely dislocated from the supra-pancreatic region. Moreover, the left gastric artery branched three gastric branches, although the right gastric artery was absent. Robotic surgery enabled the safe and precise gastrectomy and lymphadenectomy.

Inducible disruption of Tet genes results in myeloid malignancy, readthrough transcription, and a heterochromatin-to-euchromatin switch

The three mammalian TET dioxygenases oxidize the methyl group of 5-methylcytosine in DNA, and the oxidized methylcytosines are essential intermediates in all known pathways of DNA demethylation. To define the in vivo consequences of complete TET deficiency, we inducibly deleted all three Tet genes in the mouse genome. Tet1/2/3-inducible TKO (iTKO) mice succumbed to acute myeloid leukemia (AML) by 4 to 5 wk. Single-cell RNA sequencing of Tet iTKO bone marrow cells revealed the appearance of new myeloid cell populations characterized by a striking increase in expression of all members of the stefin/cystatin gene cluster on mouse chromosome 16. In patients with AML, high stefin/cystatin gene expression correlates with poor clinical outcomes. Increased expression of the clustered stefin/cystatin genes was associated with a heterochromatin-to-euchromatin compartment switch with readthrough transcription downstream of the clustered stefin/cystatin genes as well as other highly expressed genes, but only minor changes in DNA methylation. Our data highlight roles for TET enzymes that are distinct from their established function in DNA demethylation and instead involve increased transcriptional readthrough and changes in three-dimensional genome organization.

Conventional and pathogenic Th2 cells in inflammation, tissue repair, and fibrosis

Type 2 helper T (Th2) cells, a subset of CD4⁺ T cells, play an important role in the host defense against pathogens and allergens by producing Th2 cytokines, such as interleukin-4 (IL-4), IL-5, and IL-13, to trigger inflammatory responses. Emerging evidence reveals that Th2 cells also contribute to the repair of injured tissues after inflammatory reactions. However, when the tissue repair process becomes chronic, excessive, or uncontrolled, pathological fibrosis is induced, leading to organ failure and death. Thus, proper control of Th2 cells is needed for complete tissue repair without the induction of fibrosis. Recently, the existence of pathogenic Th2 (Tpath2) cells has been revealed. Tpath2 cells produce large amounts of Th2 cytokines and induce type 2 inflammation when activated by antigen exposure or tissue injury. In recent studies, Tpath2 cells are suggested to play a central role in the induction of type 2 inflammation whereas the role of Tpath2 cells in tissue repair and fibrosis has been less reported in comparison to conventional Th2 cells. In this review, we discuss the roles of conventional Th2 cells and pathogenic Th2 cells in the sequence of tissue inflammation, repair, and fibrosis.

The Albumin-Bilirubin Score Is a Prognostic Factor for Gastric Cancer Patients Who Receive Curative Treatment

BACKGROUND/AIM

The albumin-bilirubin (ALBI) score is a promising tool for the evaluation of the perioperative hepatic function. The present study aimed to evaluate the clinical impact of the preoperative ALBI status in patients with gastric cancer (GC) who received curative treatment.

PATIENTS AND METHODS

The present study included 244 patients who underwent curative treatment for GC between 2005 and 2018. The risk factors for overall survival (OS) and recurrence-free survival (RFS) were identified.

RESULTS

Based on the 3- and 5-year OS rates, we set the cut-off value for the ALBI score at -2.7849. The 3- and 5-year OS rates were 87.3% and 80.9%, respectively, in the ALBI-low group, and 66.9% and 60.6% in the ALBI-high group; these differences were statistically significant (p<0.001). The ALBI score was included in the final multivariate analysis model [Hazard ratio (HR)=2.120, 95% confidence interval (CI)=1.177-3.818, p=0.012]. Similar results were observed for RFS. In addition, the ALBI score correlated with the introduction of postoperative adjuvant chemotherapy.

CONCLUSION

The preoperative ALBI score correlated with both the OS and RFS of GC patients as well as the clinical course of adjuvant chemotherapy. Taken together, the ALBI score is a promising prognostic factor for GC.

Abstract 6320: Connecting TET2 deficiency with inflammation in CMML and anti-tumor responses

Chronic Myelomonocytic Leukemia (CMML) is a clonal hematologic disorder of older individuals characterized by monocytosis and increased risk of progression to acute myeloid leukemia (AML). Although CMML is characterized by relatively low genetic complexity consistent with clonal expansion, loss-of-function mutations in ten-eleven translocation 2 (TET2) protein are frequent and reported in almost 60% of CMML cases. Consistent with this finding, deletion of the Tet2 gene in mice leads to CMML-like disease. TET2 restrains inflammatory signals through various means, for instance by directly suppressing the expression of the IL6 gene in mouse myeloid cells by recruiting histone deacetylases. Conversely, the levels of pre-inflammatory cytokines including IL6 correlate with pre-leukemic proliferation of Tet2-deficient mouse monocytes and other myeloid cells, suggesting that Tet2 deficiency increases IL-6 expression and increased IL-6 expression in turn drives the proliferation of Tet2-deficient myeloid-lineage cells in a positive feedback loop. This scenario may operate in CMML patients, who show increased levels of inflammatory cytokines and increased expression of interferon-induced genes compared to age-matched healthy individuals. To gain insight into the connection between inflammation caused by TET deficiency and monocyte hyperproliferation, we set up cultures of bone marrow derived macrophages (BMDMs) from inducible TET deficient mice. Using this model, we found that TET-deficient BMDMs show increased proliferation compared to wild type controls; moreover, LPS stimulation leads to significantly increased expression of IL6 and IL1b in TET-deficient BMDMs. Our previous RNA sequencing of expanded TET-deficient myeloid cells in vivo showed that TET deficiency correlated with increased expression of transposable elements (TEs) and induced a DNA damage response, leading us to hypothesize that TET deficiency and increased TE expression may activate DNA and RNA sensing pathways and induce sterile inflammation. I am currently using several molecular approaches to delineate the potential connection of TET deficiency with endogenous inflammation in CMML. There is growing evidence that TET deficiency or non-specific inhibition of TET enzymes in CD8 T cells can potentiate anti-tumor responses. I am now asking whether the TET deficiency-inflammation axis I observe in BMDMs might also enhance anti-tumor responses by increasing proinflammatory responses and hence T cell recruitment and anti-tumor activity.

Citation Format: Anup Kumar Singh, Atsushi Onodera, Hugo Sepulveda, Carlos Angel, Anjana Rao. Connecting TET2 deficiency with inflammation in CMML and anti-tumor responses [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6320.

Selective Growth Suppressive Effect of Pravastatin on Senescent Human Lung Fibroblasts

Various chemical reagents containing inhibitors of mitochondrial activity, antioxidants, nuclear factor-kappa B (NF-kB) inhibitor, mammalian target of rapamycin (mTOR) inhibitor and other clinical therapeutics were screened in order to identify those that selectively decrease the viability of senescent human lung fibroblasts. Cell viability was measured using the CCK-8 assay. The results showed that pravastatin, a drug for hyperlipidemia, decreased the viability of senescent cells but not non-senescent cells. The effect of pravastatin on senescent cells is thought to be due to the inhibition of cell proliferation, rather than cell death. The effect of pravastatin was further investigated using the glucose metabolism assay, which showed that glucose consumption was inhibited both in non-senescent and senescent cells and intracellular nicotinamide adenine dinucleotide (NAD) was decreased in senescent cells. Changes to the mRNA expression levels of senescence-associated genes in response to pravastatin treatment were quantified by real-time-qPCR. There were no significant changes in the relative mRNA expression levels of IL-1β, p16, p21, and p53 in pravastatin-treated non-senescent cells, whereas the expression of IL-1β and p16 were increased by pravastatin only in senescent cells. The results of this study suggest that pravastatin does not induce senolysis, but rather selectively inhibits the proliferation of senescent cells and that cellular senescence is enhanced by decreasing intracellular NAD and promoting IL-1β production.

A Case of Robotic Posterior Rectopexy for Full-thickness Rectal Prolapse

We describe our experience with robotic posterior rectopexy for a patient with full-thickness rectal prolapse. To our knowledge, this is the first report of such a case in the literature. A 94-year-old woman presented with a history of gradually worsening rectal prolapse. On examination, we found that the rectum was completely prolapsed, and we observed a prolapsed intestinal tract. Surgery was indicated and robotic rectopexy was performed without intraoperative complications. The postoperative course was uneventful, and she was discharged 10 days after the operation. One year later, there were no signs of recurrence. Robotic surgery has become common in recent years. We used robotic surgery for rectopexy, including the suturing procedure. Suturing in robotic surgery is easier than that in laparoscopic surgery, and we demonstrated that robotic rectopexy could be safely and easily performed. The trial was registered in the UMIN clinical trial registry (number 000040378).

Epigenetic regulation of inflammation by CxxC domain-containing proteins

Epigenetic regulation of gene transcription in the immune system is important for proper control of protective and pathogenic inflammation. Aberrant epigenetic modifications are often associated with dysregulation of the immune cells, including lymphocytes and macrophages, leading to pathogenic inflammation and autoimmune diseases. Two classical epigenetic markers-histone modifications and DNA cytosine methylation, the latter is the 5 position of the cytosine base in the context of CpG dinucleotides-play multiple roles in the immune system. CxxC domain-containing proteins, which basically bind to the non-methylated CpG (i.e., epigenetic "readers"), often function as "writers" of the epigenetic markers via their catalytic domain within the proteins or by interacting with other epigenetic modifiers. We herein report the most recent advances in our understanding of the functions of CxxC domain-containing proteins in the immune system and inflammation, mainly focusing on T cells and macrophages.

Low Preoperative Albumin-to-Globulin Ratio Is a Marker of Poor Prognosis in Patients With Esophageal Cancer

AIM

Recent studies have reported that the albumin-to-globulin ratio (AGR) may be a useful inflammatory-nutritional biomarker to predict postoperative complications and poor prognosis in various types of patients with cancer. However, its prognostic value in patients with esophageal cancer is still unclear. We aimed to examine the utility of the AGR for predicting the short- and long-term outcomes in patients with esophageal cancer who underwent curative resection.

PATIENTS AND METHODS

This was a retrospective cohort analysis reviewing the medical records of consecutive patients who underwent esophagectomy for clinical stage I to III esophageal cancer at Yokohama City University. A total of 105 patients were identified between 2005 and 2018. The overall survival (OS), recurrence-free survival (RFS), and postoperative complication rates were compared between patients with high AGR (>1.48) and those with low AGR (≤1.48) group.

RESULTS

A total of 57 and 48 patients were classified into the high and low AGR groups, respectively. There was no significant difference between the two groups in the rate of overall postoperative complications of more than Clavien-Dindo grade 3 (50.9% vs. 54.2%, p=0.85). The long-term findings showed that 5-year OS and RFS rates were significantly better for the group with a high AGR (67.2% vs. 33.8%, p<0.001 and 51.6% vs. 28.5%, p=0.003, respectively).

CONCLUSION

This study suggests that a low preoperative AGR is a risk factor for poor RFS and OS in patients who are planning to undergo curative surgery for esophageal cancer. AGR may be a useful biomarker for establishing treatment strategies to improve patients' survival.

CD4 + T cells in inflammatory diseases : pathogenic T-helper cells and the CD69-Myl9 system

CD4 + T cells direct immune responses against infectious microorganisms but are also involved in the pathogenesis of inflammatory diseases. In the last two to three decades, various researchers have identified and characterized several functional CD4 + T cell subsets, including T-helper 1 (Th1), Th2, Th9 and Th17 cells and regulatory T (Treg) cells. In this mini-review, we introduce the concept of pathogenic Th cells that induce inflammatory diseases with a model of disease induction by a population of pathogenic Th cells; "pathogenic Th population disease-induction model". We will focus on Th2 cells that induce allergic airway inflammation-pathogenic Th2 cells (Tpath2 cells)-and discuss the nature of Tpath2 cells that shape the pathology of chronic inflammatory diseases. Various Tpath2 cell subsets have been identified and their unique features are summarized in mouse and human systems. Second, we will discuss how Th cells migrate and are maintained in chronic inflammatory lesions. We propose a model known as the "CD69-Myl9 system". CD69 is a cell surface molecule expressed on activated T cells and interaction with its ligand myosin light chain 9 (Myl9) is required for the induction of inflammatory diseases. Myl9 molecules in the small vessels of inflamed lungs may play a crucial role in the migration of activated T cells into inflammatory lesions. Emerging evidence may provide new insight into the pathogenesis of chronic inflammatory diseases and contribute to the development of new therapeutic strategies for intractable inflammatory disorders.

Roles of TET and TDG in DNA demethylation in proliferating and non-proliferating immune cells

BACKGROUND

TET enzymes mediate DNA demethylation by oxidizing 5-methylcytosine (5mC) in DNA to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC). Since these oxidized methylcytosines (oxi-mCs) are not recognized by the maintenance methyltransferase DNMT1, DNA demethylation can occur through "passive," replication-dependent dilution when cells divide. A distinct, replication-independent ("active") mechanism of DNA demethylation involves excision of 5fC and 5caC by the DNA repair enzyme thymine DNA glycosylase (TDG), followed by base excision repair.

RESULTS

Here by analyzing inducible gene-disrupted mice, we show that DNA demethylation during primary T cell differentiation occurs mainly through passive replication-dependent dilution of all three oxi-mCs, with only a negligible contribution from TDG. In addition, by pyridine borane sequencing (PB-seq), a simple recently developed method that directly maps 5fC/5caC at single-base resolution, we detect the accumulation of 5fC/5caC in TDG-deleted T cells. We also quantify the occurrence of concordant demethylation within and near enhancer regions in the Il4 locus. In an independent system that does not involve cell division, macrophages treated with liposaccharide accumulate 5hmC at enhancers and show altered gene expression without DNA demethylation; loss of TET enzymes disrupts gene expression, but loss of TDG has no effect. We also observe that mice with long-term (1 year) deletion of Tdg are healthy and show normal survival and hematopoiesis.

CONCLUSIONS

We have quantified the relative contributions of TET and TDG to cell differentiation and DNA demethylation at representative loci in proliferating T cells. We find that TET enzymes regulate T cell differentiation and DNA demethylation primarily through passive dilution of oxi-mCs. In contrast, while we observe a low level of active, replication-independent DNA demethylation mediated by TDG, this process does not appear to be essential for immune cell activation or differentiation.

[A Long‒Term Survival Case of Advanced Rectal Cancer with Liver and Lung, Para‒Aortic Lymph Nodes Metastasis That Responded to Multidisciplinary Therapy]

The patient was a 59‒year‒old woman. In 2005, she underwent low anterior resection plus D2 dissection for rectal cancer (pT4aN2aM0, pStage Ⅲb). In 2007, she underwent hepatic S8 subsegment resection for liver metastasis. After that, FOLFIRI therapy was performed as chemotherapy for recurrence of the right upper lung lobe and para‒aortic lymph node(PALN). CR was once obtained in both(of)PALN and lung, but PALN re‒expansion and left ovary enlargement were observed in 2009, and resection of PALN plus left ovariectomy was performed. Histological examination showed PALNs were metastases from rectal cancer and the ovary was benign. Eleven years after the first operation, she stayed alive without recurrence.

The Cxxc1 subunit of the Trithorax complex directs epigenetic licensing of CD4+ T cell differentiation

Different dynamics of gene expression are observed during cell differentiation. In T cells, genes that are turned on early or turned off and stay off have been thoroughly studied. However, genes that are initially turned off but then turned on again after stimulation has ceased have not been defined; they are obviously important, especially in the context of acute versus chronic inflammation. Using the Th1/Th2 differentiation paradigm, we found that the Cxxc1 subunit of the Trithorax complex directs transcription of genes initially down-regulated by TCR stimulation but up-regulated again in a later phase. The late up-regulation of these genes was impaired either by prolonged TCR stimulation or Cxxc1 deficiency, which led to decreased expression of Trib3 and Klf2 in Th1 and Th2 cells, respectively. Loss of Cxxc1 resulted in enhanced pathogenicity in allergic airway inflammation in vivo. Thus, Cxxc1 plays essential roles in the establishment of a proper CD4⁺ T cell immune system via epigenetic control of a specific set of genes.

[A Case of Port-Site Herniation from an Eight mm Port after Robot-Assisted Distal Gastrectomy]

A 63-year-old-woman was diagnosed with gastric cancer cStage ⅠA after ESD, and then, underwent robot-assisted distal gastrectomy. She vomited on the postoperative day 2 and then was inserted nasogastric tube. The amount of drainage from the tube was increased on the postoperative day 5, therefore, abdominal computed tomography scan was performed, which showed herniation of small bowel at the 8 mm port site in the left upper abdomen. The emergent surgery was performed because of difficulty in manual reduction. Intraoperative findings showed that small intestine was incarcerated at the left 8 mm port-site. The intestine was released by incising the fascia of hernia orifice, then, the fascia was repaired. There was no recurrence of gastric cancer and port-site hernia for 34 months after surgery. In general, the fascia of over 10 mm port site is sutured and closed to avoid port-site hernia, however, it is unclear whether the fascia of 8 mm port-site should be closed after robotic surgery. Since we experienced this case, we have also performed fascia suture on the 8 mm port-site in all cases. And then, we could prevent occurrence of port-site hernia in the 8 mm port-site.

[A Case of Malignant Melanoma Metastasized to the Small Intestine]

A case of 69-year-old man underwent resection for the plantar surface of left foot malignant melanoma and received a sentinel biopsy of left inguinal lymph node. Two years and 10 months later, a mass of 30 mm in diameter in the ileum was detected by contrast-enhanced computed tomography, which showed abnormal uptake using FDG positron emission tomography. The partial intestinal resection was performed, and then, the mass was diagnosed as metastasis of malignant melanoma by pathological examination. Malignant melanoma is highly malignant disease that frequently shows distant metastasis. Although the malignant melanoma with distant metastasis shows poor prognosis, previous studies reported the prognosis could be improved when the patient could receive curative resection for single intraabdominal metastasis. Therefore, surgical resection should be considered for the single metastasis of malignant melanoma. We report a case of malignant melanoma with ileum metastasis resected curatively with literature review.

Essential Role for CD30-Transglutaminase 2 Axis in Memory Th1 and Th17 Cell Generation

Memory helper T (Th) cells are crucial for secondary immune responses against infectious microorganisms but also drive the pathogenesis of chronic inflammatory diseases. Therefore, it is of fundamental importance to understand how memory T cells are generated. However, the molecular mechanisms governing memory Th cell generation remain incompletely understood. Here, we identified CD30 as a molecule heterogeneously expressed on effector Th1 and Th17 cells, and CD30^hi effector Th1 and Th17 cells preferentially generated memory Th1 and Th17 cells. We found that CD30 mediated signal induced Transglutaminase-2 (TG2) expression, and that the TG2 expression in effector Th cells is essential for memory Th cell generation. In fact, Cd30-deficiency resulted in the impaired generation of memory Th1 and Th17 cells, which can be rescued by overexpression of TG2. Furthermore, transglutaminase-2 (Tgm2)-deficient CD4 T cells failed to become memory Th cells. As a result, T cells from Tgm2-deficient mice displayed impaired antigen-specific antibody production and attenuated Th17-mediated allergic responses. Our data indicate that CD30-induced TG2 expression in effector Th cells is essential for the generation of memory Th1 and Th17 cells, and that CD30 can be a marker for precursors of memory Th1 and Th17 cells.

Short-term Outcomes Following Robotic-assisted Laparoscopic Surgery for Technically Demanding Rectal Cancer

AIM

To clarify the benefits of robotic-assisted laparoscopic surgery (RALS) regarding short-term outcomes in patients with technically demanding rectal cancer (TDRC).

PATIENTS AND METHODS

Between April 2015 and September 2019, 88 TDRC cases were identified from our database, and divided into the RALS (n=32) and conventional laparoscopic surgery (CLS) (n=56) groups. TDRC was defined as mid-rectal tumors presenting at least one of the following risk factors: Male sex, high body mass index, T4 stage, bulky tumor, or low rectal tumor.

RESULTS

Patient baseline characteristics were similar in both groups. One and 15 patients developed anastomotic leakage in the RALS and CLS groups (3% vs. 27%, p<0.01), respectively. The postoperative complication rate was lower in the RALS group (19% vs. 43%, p=0.03). Multivariate analysis showed the surgical approach to be an independent predictor for anastomotic leakage.

CONCLUSION

RALS has potential advantages to prevent anastomotic leakage complications in patients with TDRC.

TOX and TOX2 transcription factors cooperate with NR4A transcription factors to impose CD8+ T cell exhaustion

T cells expressing chimeric antigen receptors (CAR T cells) have shown impressive therapeutic efficacy against leukemias and lymphomas. However, they have not been as effective against solid tumors because they become hyporesponsive ("exhausted" or "dysfunctional") within the tumor microenvironment, with decreased cytokine production and increased expression of several inhibitory surface receptors. Here we define a transcriptional network that mediates CD8+ T cell exhaustion. We show that the high-mobility group (HMG)-box transcription factors TOX and TOX2, as well as members of the NR4A family of nuclear receptors, are targets of the calcium/calcineurin-regulated transcription factor NFAT, even in the absence of its partner AP-1 (FOS-JUN). Using a previously established CAR T cell model, we show that TOX and TOX2 are highly induced in CD8+ CAR+ PD-1high TIM3high ("exhausted") tumor-infiltrating lymphocytes (CAR TILs), and CAR TILs deficient in both TOX and TOX2 (Tox DKO) are more effective than wild-type (WT), TOX-deficient, or TOX2-deficient CAR TILs in suppressing tumor growth and prolonging survival of tumor-bearing mice. Like NR4A-deficient CAR TILs, Tox DKO CAR TILs show increased cytokine expression, decreased expression of inhibitory receptors, and increased accessibility of regions enriched for motifs that bind activation-associated nuclear factor κB (NFκB) and basic region-leucine zipper (bZIP) transcription factors. These data indicate that Tox and Nr4a transcription factors are critical for the transcriptional program of CD8+ T cell exhaustion downstream of NFAT. We provide evidence for positive regulation of NR4A by TOX and of TOX by NR4A, and suggest that disruption of TOX and NR4A expression or activity could be promising strategies for cancer immunotherapy.

CXCR5+ST2+memory Th2 cell reduced maturation and fecundity of Nippostrongylus brasiliensis through increase of expression of Major Basic Protein in eosinophils

Once mice experience the infection of helminth, the mice acquired resistance to the helminth. We have studied about memory responses against Nippostrongylus brasiliensis (Nb) in mice. Nb penetrates into skin, passes through the lungs and finally reaches to the gut. It has been reported that IL-33 contributes to the immune responses against re-infection of helminth. However, the IL-33-dependent immunity to Nb has not been fully defined. In this study, we identified subsets of memory Th2 (mTh2) cells; CXCR5+ST2+CD44hiTh2 cells and ST2−CD44hiTh2 cells producing IL-4 and IL-13, and increasing accumulation of eosinophils in the lungs in helminth infection. CXCR5+ST2+mTh2 cells rather than ST2− mTh2 cells strongly expressed IL-5 and increased the expression of Major Basic Protein (MBP) in eosinophils in the lungs, which is important for reduction of maturation and fecundity of Nb in the intestine. Notably, we also found ST2+Treg cells but not ST2− Treg cells can suppress the ST2+mTh2 cell-mediated reduction of fecundity of Nb. Taken together, these findings indicate that we identified a mechanism against helminth elicited by a subpopulation of IL-5-producing Th2 cells through the accumulation of eosinophils strongly expressing MBP in the lungs. This would be helpful to establish the drugs and/or vaccination against helminth,

ACC1 determines memory potential of individual CD4+ T cells by regulating de novo fatty acid biosynthesis

Immunological memory is central to adaptive immunity and protection from disease. Changing metabolic demands as antigen-specific T cells transition from effector to memory cells have been well documented, but the cell-specific pathways and molecules that govern this transition are poorly defined. Here we show that genetic deletion of ACC1, a rate-limiting enzyme in fatty acid biosynthesis, enhances the formation of CD4⁺ T memory cells. ACC1-deficient effector helper T (Th) cells have similar metabolic signatures to wild-type memory Th cells, and expression of the gene encoding ACC1, Acaca, was inversely correlated with a memory gene signature in individual cells. Inhibition of ACC1 function enhances memory T cell formation during parasite infection in mice. Using single-cell analyses we identify a memory precursor-enriched population (CCR7^hiCD137^lo) present during early differentiation of effector CD4⁺ T cells. Our data indicate that fatty acid metabolism directs cell fate determination during the generation of memory CD4⁺ T cells.

Epigenetic and Transcriptional Regulation in the Induction, Maintenance, Heterogeneity, and Recall-Response of Effector and Memory Th2 Cells

Antigen-primed T cells respond to restimulation much faster than naïve T cells and form the cellular basis of immunological memory. The formation of memory Th2 cells starts when naïve CD4 T cells are transformed into effector Th2 cells and is completed after antigen clearance and a long-term resting phase accompanied by epigenetic changes in the Th2 signature genes. Memory Th2 cells maintain their functions and acquired heterogeneity through epigenetic machinery, on which the recall-response of memory Th2 cells is also dependent. We provide an overview of the epigenetics in the whole Th2 cell cycle, mainly focusing on two different histone lysine methyltransferase complexes: the Polycomb and Trithorax groups. We finally discuss the pathophysiology and potential therapeutic strategies for the treatment of Th2-mediated inflammatory diseases in mice and humans.

Role of leukotriene B4 12-hydroxydehydrogenase in α-galactosylceramide-pulsed dendritic cell therapy for non-small cell lung cancer

Invariant natural killer T (iNKT) cells exhibit potent antitumor effects upon activation by recognizing a specific glycolipid antigen. We previously performed phase I-II clinical studies to utilize iNKT cells using α-galactosylceramide-pulsed dendritic cells and identified leukotriene B4 12-hydroxydehydrogenase (LTB4DH) as a biomarker highly expressed in T cells derived from non-small cell lung cancer (NSCLC) patients who showed prolonged survival in respond to the iNKT cell immunotherapy. Because LTB4DH expression correlated with prolonged survival of NSCLC patients, we considered LTB4DH to play a role in iNKT cell immunotherapy. We herein demonstrate that the overexpression of LTB4DH in CD4⁺ or CD8⁺ T cells increases interferon-γ production and tumoricidal activity in the presence of prostaglandin E₂. Moreover, the expression of granzyme a, granzyme b, and perforin mRNA was increased in LTB4DH-overexpressing cells.

Amphiregulin-Producing Pathogenic Memory T Helper 2 Cells Instruct Eosinophils to Secrete Osteopontin and Facilitate Airway Fibrosis

Memory T cells provide long-lasting protective immunity, and distinct subpopulations of memory T cells drive chronic inflammatory diseases such as asthma. Asthma is a chronic allergic inflammatory disease with airway remodeling including fibrotic changes. The immunological mechanisms that induce airway fibrotic changes remain unknown. We found that interleukin-33 (IL-33) enhanced amphiregulin production by the IL-33 receptor, ST2^hi memory T helper 2 (Th2) cells. Amphiregulin-epidermal growth factor receptor (EGFR)-mediated signaling directly reprogramed eosinophils to an inflammatory state with enhanced production of osteopontin, a key profibrotic immunomodulatory protein. IL-5-producing memory Th2 cells and amphiregulin-producing memory Th2 cells appeared to cooperate to establish lung fibrosis. The analysis of polyps from patients with eosinophilic chronic rhinosinusitis revealed fibrosis with accumulation of amphiregulin-producing CRTH2^hiCD161^hiCD45RO⁺CD4⁺ Th2 cells and osteopontin-producing eosinophils. Thus, the IL-33-amphiregulin-osteopontin axis directs fibrotic responses in eosinophilic airway inflammation and is a potential target for the treatment of fibrosis induced by chronic allergic disorders.

Epigenetic regulation of T-helper cell differentiation, memory, and plasticity in allergic asthma

An estimated 300 million people currently suffer from asthma, which causes approximately 250 000 deaths a year. Allergen-specific T-helper (Th) cells produce cytokines that induce many of the hallmark features of asthma including airways hyperreactivity, eosinophilic and neutrophilic inflammation, mucus hypersecretion, and airway remodeling. Cytokine-producing Th subsets including Th1 (IFN-γ), Th2 (IL-4, IL-5, IL-13), Th9 (IL-9), Th17 (IL-17), Th22 (IL-22), and T regulatory (IL-10) cells have all been suggested to play a role in the development of asthma. Th differentiation involves genetic regulation of gene expression through the concerted action of cytokines, transcription factors, and epigenetic regulators. We describe how Th differentiation and plasticity is regulated by epigenetic histone and DNA modifications, with a focus on the regulation of histone methylation by members of the polycomb and trithorax complexes. In addition, we outline environmental influences that could influence epigenetic regulation of Th cells and discuss the potential to regulate Th plasticity and function through drugs targeting the epigenetic machinery. It is also becoming apparent that epigenetic regulation of allergen-specific memory Th cells may be important in the development and persistence of chronic allergies. Finally, we describe how epigenetic modifiers regulate cytokine memory in Th cells and describe recently identified hybrid, plastic, and pathogenic memory Th subsets the context of allergic asthma.

The Transcription Factor T-bet Limits Amplification of Type I IFN Transcriptome and Circuitry in T Helper 1 Cells

Host defense requires the specification of CD4⁺ helper T (Th) cells into distinct fates, including Th1 cells that preferentially produce interferon-γ (IFN-γ). IFN-γ, a member of a large family of anti-pathogenic and anti-tumor IFNs, induces T-bet, a lineage-defining transcription factor for Th1 cells, which in turn supports IFN-γ production in a feed-forward manner. Herein, we show that a cell-intrinsic role of T-bet influences how T cells perceive their secreted product in the environment. In the absence of T-bet, IFN-γ aberrantly induced a type I IFN transcriptomic program. T-bet preferentially repressed genes and pathways ordinarily activated by type I IFNs to ensure that its transcriptional response did not evoke an aberrant amplification of type I IFN signaling circuitry, otherwise triggered by its own product. Thus, in addition to promoting Th1 effector commitment, T-bet acts as a repressor in differentiated Th1 cells to prevent abberant autocrine type I IFN and downstream signaling.

Th2 Cells in Health and Disease

Helper T (Th) cell subsets direct immune responses by producing signature cytokines. Th2 cells produce IL-4, IL-5, and IL-13, which are important in humoral immunity and protection from helminth infection and are central to the pathogenesis of many allergic inflammatory diseases. Molecular analysis of Th2 cell differentiation and maintenance of function has led to recent discoveries that have refined our understanding of Th2 cell biology. Epigenetic regulation of Gata3 expression by chromatin remodeling complexes such as Polycomb and Trithorax is crucial for maintaining Th2 cell identity. In the context of allergic diseases, memory-type pathogenic Th2 cells have been identified in both mice and humans. To better understand these disease-driving cell populations, we have developed a model called the pathogenic Th population disease induction model. The concept of defined subsets of pathogenic Th cells may spur new, effective strategies for treating intractable chronic inflammatory disorders.

Myosin light chains 9 and 12 are functional ligands for CD69 that regulate airway inflammation

Recent decades have witnessed a rapid worldwide increase in chronic inflammatory disorders such as asthma. CD4⁺ T helper 2 cells play critical roles in the pathogenesis of allergic airway inflammation, and CD69 expression on activated CD4 T cells is required to induce allergic inflammation in tissues. However, how CD69 mechanistically controls allergic inflammation remains poorly defined. In lymphoid tissues, CD69 regulates cellular retention through inhibition of S1P1 expression and requires no specific ligands to function. In contrast, we show herein that myosin light chain (Myl) 9 and Myl12 are new functional ligands for CD69. Blockade of CD69-Myl9/12 interaction ameliorates allergic airway inflammation in ovalbumin-induced and house dust mite-induced mouse models of asthma. Within the inflamed mouse airways, we found that the expression of Myl9/12 was increased and that platelet-derived Myl9/12 localized to the luminal surface of blood vessels and formed intravascular net-like structures. Analysis of nasal polyps of eosinophilic chronic rhinosinusitis patients revealed that Myl9/12 expression was increased in inflammatory lesions and was distributed within net-like structures in the intravascular space. In addition, we detected Myl9/12 in perivascular spaces where many CD69⁺ cells were positioned within Myl9/12 structures. Thus, CD69-Myl9/12 interaction is a key event in the recruitment of activated CD69⁺ T cells to inflamed tissues and could be a therapeutic target for intractable airway inflammatory diseases.

[Devised a New Preoperative Simulation Using (99m)Tc-GSA SPECT Quantitative Method for Liver Resection]

PURPOSE

We developed a new imaging method to assess liver function by analyzing the amount of liver asialo single photon emission computed tomography (SPECT) using technetium-99m diethylenetriamine pentaacetic acid galactosyl human serum albumin ((99m)Tc-GSA) injection. A preoperative simulation using various regions of interest (ROIs) was performed, and the usefulness of the method for predicting the residual liver function was examined.

METHODS

Ninety-three patients were enrolled who underwent both asialo scintigraphy and dynamic computed tomography (CT) scanning. The two-dimensional dynamic data were analyzed using the Patlak plot method to calculate Kup and perfusion index (PI). The PIi (the quantity of GSA in a reference slice) was calculated using the PI. The qualitative SPECT data were analyzed using the quantitative images and the PIi, and we calculated the amount of asialo uptake per unit, which we named asialo uptake index (AUI). Volume registration was done between the collected breath holding SPECT data and CT images.

RESULTS

We were able to obtain AUI images and calculate the liver sparing ability by analyzing the two-dimensional data. The AUI and each of the liver counts (HH15, LHL15, LU15, and PI) were correlated, and we could perform the preoperative simulation using any ROI.

CONCLUSION

Preoperative simulation for the outcome of hepatectomy could be done using our new method employing quantitative SPECT.

Asymmetric Action of STAT Transcription Factors Drives Transcriptional Outputs and Cytokine Specificity

Interleukin-6 (IL-6) and IL-27 signal through a shared receptor subunit and employ the same downstream STAT transcription proteins, but yet are ascribed unique and overlapping functions. To evaluate the specificity and redundancy for these cytokines, we quantified their global transcriptomic changes and determined the relative contributions of STAT1 and STAT3 using genetic models and chromatin immunoprecipitation-sequencing (ChIP-seq) approaches. We found an extensive overlap of the transcriptomes induced by IL-6 and IL-27 and few examples in which the cytokines acted in opposition. Using STAT-deficient cells and T cells from patients with gain-of-function STAT1 mutations, we demonstrated that STAT3 is responsible for the overall transcriptional output driven by both cytokines, whereas STAT1 is the principal driver of specificity. STAT1 cannot compensate in the absence of STAT3 and, in fact, much of STAT1 binding to chromatin is STAT3 dependent. Thus, STAT1 shapes the specific cytokine signature superimposed upon STAT3's action.

Sox5 and c-Maf cooperatively induce Th17 cell differentiation via RORγt induction as downstream targets of Stat3

A novel isoform of Sox5, Sox5t, and c-Maf activate RORγt to induce Th17 cells. Sox5^−/− mice exhibit impaired Th17 differentiation and are thus resistant to EAE and delayed-type hypersensitivity.

Stat3 signaling is essential for the induction of RORγt and subsequent Th17 cell differentiation. However, the downstream targets of Stat3 for RORγt expression remain largely unknown. We show here that a novel isoform of Sox5, named Sox5t, is induced in Th17 cells in a Stat3-dependent manner. In vivo, T cell–specific Sox5-deficient mice exhibit impaired Th17 cell differentiation and are resistant to experimental autoimmune encephalomyelitis and delayed-type hypersensitivity. Retrovirus-mediated induction of Sox5 together with c-Maf induces Th17 cell differentiation even in Stat3-deficient CD4⁺ T cells but not in RORγt-deficient CD4⁺ T cells, indicating that Sox5 and c-Maf induce Th17 cell differentiation as downstream effectors of Stat3 and as upstream inducers of RORγt. Moreover, Sox5 physically associates with c-Maf via the HMG domain of Sox5 and DNA-binding domain of c-Maf, and Sox5 together with c-Maf directly activates the promoter of RORγt in CD4⁺ T cells. Collectively, our results suggest that Sox5 and c-Maf cooperatively induce Th17 cell differentiation via the induction of RORγt as downstream targets of Stat3.

The polycomb protein Ezh2 regulates differentiation and plasticity of CD4(+) T helper type 1 and type 2 cells

After antigen encounter by CD4(+) T cells, polarizing cytokines induce the expression of master regulators that control differentiation. Inactivation of the histone methyltransferase Ezh2 was found to specifically enhance T helper 1 (Th1) and Th2 cell differentiation and plasticity. Ezh2 directly bound and facilitated correct expression of Tbx21 and Gata3 in differentiating Th1 and Th2 cells, accompanied by substantial trimethylation at lysine 27 of histone 3 (H3K27me3). In addition, Ezh2 deficiency resulted in spontaneous generation of discrete IFN-γ and Th2 cytokine-producing populations in nonpolarizing cultures, and under these conditions IFN-γ expression was largely dependent on enhanced expression of the transcription factor Eomesodermin. In vivo, loss of Ezh2 caused increased pathology in a model of allergic asthma and resulted in progressive accumulation of memory phenotype Th2 cells. This study establishes a functional link between Ezh2 and transcriptional regulation of lineage-specifying genes in terminally differentiated CD4(+) T cells.

Genome-Wide Gene Expression Profiling Revealed a Critical Role for GATA3 in the Maintenance of the Th2 Cell Identity

Functionally polarized CD4+ T helper (Th) cells such as Th1, Th2 and Th17 cells are central to the regulation of acquired immunity. However, the molecular mechanisms governing the maintenance of the polarized functions of Th cells remain unclear. GATA3, a master regulator of Th2 cell differentiation, initiates the expressions of Th2 cytokine genes and other Th2-specific genes. GATA3 also plays important roles in maintaining Th2 cell function and in continuous chromatin remodeling of Th2 cytokine gene loci. However, it is unclear whether continuous expression of GATA3 is required to maintain the expression of various other Th2-specific genes. In this report, genome-wide DNA gene expression profiling revealed that GATA3 expression is critical for the expression of a certain set of Th2-specific genes. We demonstrated that GATA3 dependency is reduced for some Th2-specific genes in fully developed Th2 cells compared to that observed in effector Th2 cells, whereas it is unchanged for other genes. Moreover, effects of a loss of GATA3 expression in Th2 cells on the expression of cytokine and cytokine receptor genes were examined in detail. A critical role of GATA3 in the regulation of Th2-specific gene expression is confirmed in in vivo generated antigen-specific memory Th2 cells. Therefore, GATA3 is required for the continuous expression of the majority of Th2-specific genes involved in maintaining the Th2 cell identity.

The histone methyltransferase Ezh2 regulates differentiation and plasticity of CD4 T helper cells. (P1334)

Upon encountering antigen, naïve CD4 T cells rapidly differentiate into discrete subsets of effector T helper (Th) cells that direct immune responses to different types of infection. Polarizing cytokines induce the expression of lineage-specifying genes (Tbx21 for Th1 cells and Gata3 for Th2 cells) that control differentiation. We found that the histone H3K27 methyltransferase Ezh2 controls differentiation of Th1 and Th2 cells, and that inactivation of Ezh2 enhances plasticity of both of these subsets. Tbx21 and Gata3 experienced large changes in Ezh2 occupancy during Th differentiation, and inactivation of Ezh2 depleted H3K27-trimethylation (H3K27-Me3) at these loci. Additionally, loss of Ezh2 caused increased pathology in a mouse model of allergic asthma and progressive accumulation of memory phenotype Th2 cells in vivo. This study establishes a functional link between Ezh2 and transcriptional regulation of lineage-specifying genes in terminally differentiated peripheral T cells via H3K27-Me3. These data may therefore contribute to the development of therapies that target this pathway to enhance or repress immune responses in human diseases.

Memory type 2 helper T cells induce long-lasting antitumor immunity by activating natural killer cells

Functionally polarized helper T cells (Th cells) play crucial roles in the induction of tumor immunity. There is considerable knowledge about the contributions of IFN-producing Th1 cells that supports the role of cytotoxic cluster of differentiation (CD8) T cells and natural killer (NK) cells, but much less is known about how IL-4-producing Th2 cells contribute to tumor immunity. In this study, we investigated the cellular and molecular mechanisms employed by memory Th2 cells in sustaining tumor immunity by using a mouse model system wherein ovalbumin (OVA) is used as a specific tumor antigen. In this model, we found that OVA-specific memory Th2 cells exerted potent and long-lasting antitumor effects against NK-sensitive OVA-expressing tumor cells, wherein antitumor effects were mediated by NK cells. Specifically, NK cell cytotoxic activity and expression of perforin and granzyme B were dramatically enhanced by the activation of memory Th2 cells. Interleukin 4 (IL-4) produced by memory Th2 cells in vivo was critical for the antitumor effects of the NK cells, which IL-4 directly stimulated to induce their perforin- and granzyme-B-dependent cytotoxic activity. Our findings show that memory Th2 cells can induce potent antitumor immunity through IL-4-induced activation of NK cells, suggesting potential applications in cellular therapy for cancer patients.

Genome-wide analysis reveals unique regulation of transcription of Th2-specific genes by GATA3

Differentiation of naive CD4 T cells into Th2 cells is accompanied by chromatin remodeling and increased expression of a set of Th2-specific genes, including those encoding Th2 cytokines. IL-4-mediated STAT6 activation induces high levels of transcription of GATA3, a master regulator of Th2 cell differentiation, and enforced expression of GATA3 induces Th2 cytokine expression. However, it remains unclear whether the expression of other Th2-specific genes is induced directly by GATA3. A genome-wide unbiased chromatin immunoprecipitation assay coupled with massive parallel sequencing analysis revealed that GATA3 bound to 1279 genes selectively in Th2 cells, and 101 genes in both Th1 and Th2 cells. Simultaneously, we identified 26 highly Th2-specific STAT6-dependent inducible genes by DNA microarray analysis-based three-step selection processes, and among them 17 genes showed GATA3 binding. We assessed dependency on GATA3 for the transcription of these 26 Th2-specific genes, and 10 genes showed increased transcription in a GATA3-dependent manner, whereas 16 genes showed no significant responses. The transcription of the 16 GATA3-nonresponding genes was clearly increased by the introduction of an active form of STAT6, STAT6VT. Therefore, although GATA3 has been recognized as a master regulator of Th2 cell differentiation, many Th2-specific genes are not regulated by GATA3 itself, but in collaboration with STAT6.

STAT6-mediated displacement of polycomb by trithorax complex establishes long-term maintenance of GATA3 expression in T helper type 2 cells

Polycomb group (PcG) and trithorax group (TrxG) complexes exert opposing effects on the maintenance of the transcriptional status of the developmentally regulated Hox genes. In this study, we show that activation of STAT6 induces displacement of the PcG complex by the TrxG complex at the upstream region of the gene encoding GATA3, a transcription factor essential for T helper type 2 (Th2) cell differentiation. Once Th2 cells differentiate, TrxG complex associated with the TrxG component Menin binds to the whole GATA3 gene locus, and this binding is required for the long-term maintenance of expression of GATA3 and Th2 cytokine. Thus, STAT6-mediated displacement of PcG by the TrxG complex establishes subsequent STAT6-independent maintenance of GATA3 expression in Th2 cells via the recruitment of the Menin-TrxG complex.