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.

CD103hi Treg cells constrain lung fibrosis induced by CD103lo tissue-resident pathogenic CD4 T cells.

Tissue-resident memory T cells (TRM cells) are crucial mediators of adaptive immunity in nonlymphoid tissues. However, the functional heterogeneity and pathogenic roles of CD4+ TRM cells that reside within chronic inflammatory lesions remain unknown. We found that CD69hiCD103lo CD4+ TRM cells produced effector cytokines and promoted the inflammation and fibrotic responses induced by chronic exposure to Aspergillus fumigatus. Simultaneously, immunosuppressive CD69hiCD103hiFoxp3+ CD4+ regulatory T cells were induced and constrained the ability of pathogenic CD103lo TRM cells to cause fibrosis. Thus, lung tissue-resident CD4+ T cells play crucial roles in the pathology of chronic lung inflammation, and CD103 expression defines pathogenic effector and immunosuppressive tissue-resident cell subpopulations in the inflamed lung.

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, ST2hi 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 CRTH2hiCD161hiCD45RO+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.

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.

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.

Thioredoxin-interacting protein is essential for memory T cell formation via the regulation of the redox metabolism.

CD4+ memory T cells are central to long-lasting protective immunity and are involved in shaping the pathophysiology of chronic inflammation. While metabolic reprogramming is critical for the generation of memory T cells, the mechanisms controlling the redox metabolism in memory T cell formation remain unclear. We found that reactive oxygen species (ROS) metabolism changed dramatically in T helper-2 (Th2) cells during the contraction phase in the process of memory T cell formation. Thioredoxin-interacting protein (Txnip), a regulator of oxidoreductase, regulated apoptosis by scavenging ROS via the nuclear factor erythroid 2-related factor 2 (Nrf2)-biliverdin reductase B (Blvrb) pathway. Txnip regulated the pathology of chronic airway inflammation in the lung by controlling the generation of allergen-specific pathogenic memory Th2 cells in vivo. Thus, the Txnip-Nrf2-Blvrb axis directs ROS metabolic reprogramming in Th2 cells and is a potential therapeutic target for intractable chronic inflammatory diseases.

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.

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.

The transcription factor Sox4 is a downstream target of signaling by the cytokine TGF-ß and suppresses T(H)2 differentiation.

Sox4 is a transcription factor that regulates various developmental processes. Here we show that Sox4 was induced by TGF-ß and negatively regulated the transcription factor GATA-3, the master regulator of function of T helper type 2 (T(H)2) cells, by two distinct mechanisms. First, Sox4 bound directly to GATA-3, preventing its binding to GATA-3 consensus DNA sequences. Second, Sox4 bound to the promoter region of the gene encoding interleukin 5 (IL-5), a T(H)2 cytokine, and prevented binding of GATA-3 to this promoter. T(H)2 cell-driven airway inflammation was modulated by alterations in Sox4 expression. Thus, Sox4 acted as a downstream target of TGF-ß to inhibit GATA-3 function, T(H)2 differentiation and T(H)2 cell-mediated inflammation.

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.

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

CD4+ T cells not only direct immune responses against infectious micro-organisms 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: the '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.

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.

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.

CXCR6+ST2+ memory T helper 2 cells induced the expression of major basic protein in eosinophils to reduce the fecundity of helminth.

Memory T helper (mTh) cells play important roles in the reinfection of pathogens and drive the pathogenesis of diseases. While recent studies have characterized the pathogenic mTh2 cell subpopulations driving allergic inflammation, those that induce immune responses against helminth infection remain unknown. We found that IL-5-producing CXCR6+ST2+CD44+ mTh2 cells play a crucial role in the IL-33-dependent inhibition of the fecundity of helminth, whereas other ST2- mTh2 cells do not. Although both cell types induced the infiltration of granulocytes, especially eosinophils, into the lungs in response to helminth infection, the ST2+ mTh2 cell-induced eosinophils expressed higher levels of major basic protein (MBP), which is important for reducing the fecundity of Nippostrongylus brasiliensis (Nb), than ST2- mTh2 cell-induced ones. Notably, we also found that ST2+ Treg cells but not ST2- Treg cells suppressed CXCR6+ST2+ mTh2 cell-mediated immune responses. Taken together, these findings show that we identified a mechanism against helminth elicited by a subpopulation of IL-5-producing mTh2 cells through the accumulation of eosinophils strongly expressing MBP in the lungs.

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.

[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.

Ezh2 controls development of natural killer T cells, which cause spontaneous asthma-like pathology.

BACKGROUND: Natural killer T (NKT) cells express a T-cell receptor that recognizes endogenous and environmental glycolipid antigens. Several subsets of NKT cells have been identified, including IFN-γ-producing NKT1 cells, IL-4-producing NKT2 cells, and IL-17-producing NKT17 cells. However, little is known about the factors that regulate their differentiation and respective functions within the immune system. OBJECTIVE: We sought to determine whether the polycomb repressive complex 2 protein enhancer of zeste homolog 2 (Ezh2) restrains pathogenicity of NKT cells in the context of asthma-like lung disease. METHODS: Numbers of invariant natural killer T (iNKT) 1, iNKT2, and iNKT17 cells and tissue distribution, cytokine production, lymphoid tissue localization, and transcriptional profiles of iNKT cells from wild-type and Ezh2 knockout (KO) iNKT mice were determined. The contribution of NKT cells to development of spontaneous and house dust mite-induced airways pathology, including airways hyperreactivity (AHR) to methacholine, was also assessed in wild-type, Ezh2 KO, and Ezh2 KO mice lacking NKT cells. RESULTS: Ezh2 restrains development of pathogenic NKT cells, which induce spontaneous asthma-like disease in mice. Deletion of Ezh2 increased production of IL-4 and IL-13 and induced spontaneous AHR, lung inflammation, mucus production, and IgE. Increased IL-4 and IL-13 levels, AHR, lung inflammation, and IgE levels were all dependent on iNKT cells. In house dust mite-exposed animals Ezh2 KO resulted in enhanced AHR that was also dependent on iNKT cells. CONCLUSION: Ezh2 is a central regulator of iNKT pathogenicity and suppresses the ability of iNKT cells to induce asthma-like pathology.

[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.