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Background The aim of this study was to assess whether two-years treatment with Pirfenidone influences necroinflammation, fibrosis and steatosis, serum levels of TGF-β1, IL-6, TNF-α and CB1 and CB2 gene expression, in patients with chronic hepatitis C (CHC). Methods Twenty-eight patients out of 34 with CHC virus infection were enrolled in the study and received Pirfenidone (1200 mg/day) for 24 months. Six patients dropped out after 12 months of PFD. Liver biopsies and serum samples were obtained at the beginning and end of treatment. Modified HAI was calculated. CB1 and CB2 gene expression was correlated with fibrosis progression alongside with necroinflammation and steatosis. TGF-β1, IL-6, TNF-α and liver transaminases were measured in serum at two-months intervals. HCV genotype and viral load were also assessed. Quality of life was evaluated by SF36 questionnaires and the prognosis of disease was assessed with Child-Pugh score. The Wilcoxon test matched-pair signed ranks were used to analyze the outcomes. Results Intention to treat analyses were performed for biochemistry and clinical parameters. At the end of treatment, necroinflammation grading was reduced in an average of 3.2 points in 82% of patients (p < 0.05) and Ishak’s fibrosis stage decreased 2-points average in 67% of patients (p < 0.05). Steatosis decreased in 61% of patients. IL-6 and TGF-β1 serum levels decreased significantly in 93% and 67% of patients (p < 0.05), respectively, while TNF-α diminished in 47% of patients. ALT and AST tended to normalize in 81% of patients; CB2 mRNA levels increased in 86% and CB1 expression diminished in 29% of patients. Both, quality of life and Child-Pugh score improvements were reported in all patients. Conclusions Pirfenidone for two years benefits CHC patients and improves inflammation, fibrosis and steatosis in higher number of patients as previously shown for 12-months treatment with PFD. Additionally, PFD improved TGFβ1 and IL-6 levels and diminished liver expression of anti-fibrogenic receptor CB2. Trial registration ClinicalTrials.gov identifier: NCT02161952 . Protocol Registration Date: 06/11/2014.

CD4 + T cells that express the forkhead box P3 (FOXP3) transcription factor function as regulatory T (T reg ) cells and hinder effective immune responses against cancer cells 1 , 2 , 3 . Abundant T reg cell infiltration into tumors is associated with poor clinical outcomes in various types of cancers 3 , 4 , 5 , 6 , 7 . However, the role of T reg cells is controversial in colorectal cancers (CRCs), in which FOXP3 + T cell infiltration indicated better prognosis in some studies 6 , 7 , 8 , 9 . Here we show that CRCs, which are commonly infiltrated by suppression-competent FOXP3 hi T reg cells, can be classified into two types by the degree of additional infiltration of FOXP3 lo nonsuppressive T cells 10 . The latter, which are distinguished from FOXP3 + T reg cells by non-expression of the naive T cell marker CD45RA and instability of FOXP3, secreted inflammatory cytokines. Indeed, CRCs with abundant infiltration of FOXP3 lo T cells showed significantly better prognosis than those with predominantly FOXP3 hi T reg cell infiltration. Development of such inflammatory FOXP3 lo non-T reg cells may depend on secretion of interleukin (IL)-12 and transforming growth factor (TGF)-β by tissues and their presence was correlated with tumor invasion by intestinal bacteria, especially Fusobacterium nucleatum. Thus, functionally distinct subpopulations of tumor-infiltrating FOXP3 + T cells contribute in opposing ways to determining CRC prognosis. Depletion of FOXP3 hi T reg cells from tumor tissues, which would augment antitumor immunity, could thus be used as an effective treatment strategy for CRCs and other cancers, whereas strategies that locally increase the population of FOXP3 lo non-T reg cells could be used to suppress or prevent tumor formation.

Although the pathogenesis of endometriosis is not fully understood, it is often considered to be an inflammatory disease. An increasing number of studies suggest that differential expression of anti-inflammatory cytokines (e.g., interleukin-4 and -10, and transforming growth factor-β1) occurs in women with endometriosis, including in serum, peritoneal fluid and ectopic lesions. These anti-inflammatory cytokines also have indispensable roles in the progression of endometriosis, including by promoting survival, growth, invasion, differentiation, angiogenesis, and immune escape of the endometriotic lesions. In this review, we provide an overview of the expression, origin, function and regulation of anti-inflammatory cytokines in endometriosis, with brief discussion and perspectives on their future clinical implications in the diagnosis and therapy of the disease.

Regulatory T cells (T regs ) can suppress immune responses through a variety of mechanisms. One such mechanism involves the activation of a surface-bound latent form of the cytokine transforming growth factor–β1 (TGF-β1). Within the cell, newly synthesized pro-TGF-β1 homodimers form disulfide bonds with the transmembrane protein GARP, which acts to chaperone and orient the cytokine for activation at the cell surface. Liénart et al. reveal how GARP interacts with TGF-β1, using a crystal structure in which the complex was stabilized using a Fab fragment from a monoclonal antibody (MHG-8) that binds to the complex. In so doing, they also demonstrate how MHG-8 prevents membrane-associated TGF-β1 release. These structural and mechanistic insights may inform treatments of diseases with altered TGF-β1 functionality and dysfunctional T reg activity, including cancer immunotherapy. Science , this issue p. 952 A crystal structure elucidates the mechanism of antibody-mediated blockade of TGF-β1 activation and immunosuppression by regulatory T cells. Transforming growth factor–β1 (TGF-β1) is one of very few cytokines produced in a latent form, requiring activation to exert any of its vastly diverse effects on development, immunity, and cancer. Regulatory T cells (T regs ) suppress immune cells within close proximity by activating latent TGF-β1 presented by GARP (glycoprotein A repetitions predominant) to integrin αVβ8 on their surface. We solved the crystal structure of GARP:latent TGF-β1 bound to an antibody that stabilizes the complex and blocks release of active TGF-β1. This finding reveals how GARP exploits an unusual medley of interactions, including fold complementation by the amino terminus of TGF-β1, to chaperone and orient the cytokine for binding and activation by αVβ8. Thus, this work further elucidates the mechanism of antibody-mediated blockade of TGF-β1 activation and immunosuppression by T regs .

The cytokine TGF-β maintains the residency of cells of the immune system in barrier tissues. Kaplan and colleagues demonstrate that specific integrins expressed by epithelial cells activate latent TGF-β and that this is critical to maintain residency of cells of the immune system in the skin and gut. Cells of the immune system that reside in barrier epithelia provide a first line of defense against pathogens. Langerhans cells (LCs) and CD8 + tissue-resident memory T cells (T RM cells) require active transforming growth factor-β1 (TGF-β) for epidermal residence. Here we found that integrins α v β 6 and α v β 8 were expressed in non-overlapping patterns by keratinocytes (KCs) and maintained the epidermal residence of LCs and T RM cells by activating latent TGF-β. Similarly, the residence of dendritic cells and T RM cells in the small intestine epithelium also required α v β 6 . Treatment of the skin with ultraviolet irradiation decreased integrin expression on KCs and reduced the availability of active TGF-β, which resulted in LC migration. Our data demonstrated that regulated activation of TGF-β by stromal cells was able to directly control epithelial residence of cells of the immune system through a novel mechanism of intercellular communication.

The role of conventional type 1 DCs (cDC1s) in tolerance induction to solid organ allografts is unknown and important for strategies that seek to prolong allograft viability. Using a murine model deficient in cDC1s, we report cDC1s are required for donor antigen and costimulation blockade (DST + CoB) tolerance induction and survival of cardiac allografts. cDC1 deficiency led to decreases in CD4+CD25+FoxP3+ T cells within allograft and spleen tissue of transplant recipients, and this was found to be antigen specific. Donor antigen stimulation induced TGF-β1 expression in both in vivo cDC1s and in vitro Flt3L-derived cDC1s. Genetic deletion of TGF-β1 in cDC1s prevented induction of antigen-specific CD4+CD25+FoxP3+ T cells and was associated with cardiac allograft rejection. In parallel, single-cell RNA sequencing and metabolic analysis revealed upregulation of cDC1 mitochondrial metabolic signatures after in vivo exposure to DST + CoB. Genetic inactivation of cDC1 mitochondrial metabolism reduced expression of cDC1 TGF-β1, decreased antigen-specific Treg populations, and impaired allograft tolerance. Taken together, our findings implicate cDC1s in strategies to preserve solid organ allografts and also implicate mitochondrial metabolism of cDC1s as a molecular mechanism to enhance the generation of antigen-specific CD4+CD25+FoxP3+ T cells through TGF-β1.

Complement provides costimulatory signals to T cells. Medof and colleagues demonstrate that an absence of complement signaling in naive T cells generates an autoinductive loop to drive induced regulatory T cells. Signaling through the G protein–coupled receptors for the complement fragments C3a and C5a (C3aR and C5aR, respectively) by dendritic cells and CD4 + cells provides costimulatory and survival signals to effector T cells. Here we found that when signals from C3aR and C5aR were not transduced into CD4 + cells, signaling via the kinases PI(3)Kγ, Akt and mTOR ceased, activation of the kinase PKA increased, autoinductive signaling by transforming growth factor-β1 (TGF-β1) initiated and CD4 + T cells became Foxp3 + induced regulatory T cells (iT reg cells). Endogenous TGF-β1 suppressed signaling through C3aR and C5aR by preventing the production of C3a and C5a and upregulating C5L2, an alternative receptor for C5a. The absence of signaling via C3aR and C5aR resulted in lower expression of costimulatory molecules and interleukin 6 (IL-6) and more production of IL-10. The resulting iT reg cells exerted robust suppression, had enhanced stability and suppressed ongoing autoimmune disease. Antagonism of C3aR and C5aR can also induce functional human iT reg cells.

FOXP3+CD4+ regulatory T cells (Tregs) are critical for immune homeostasis and respond to local tissue cues, which control their stability and function. We explored here whether developmental endothelial locus-1 (DEL-1), which, like Tregs, increases during resolution of inflammation, promotes Treg responses. DEL-1 enhanced Treg numbers and function at barrier sites (oral and lung mucosa). The underlying mechanism was dissected using mice lacking DEL-1 or expressing a point mutant thereof, or mice with T cell-specific deletion of the transcription factor RUNX1, identified by RNA sequencing analysis of the DEL-1-induced Treg transcriptome. Specifically, through interaction with αvβ3 integrin, DEL-1 promoted induction of RUNX1-dependent FOXP3 expression and conferred stability of FOXP3 expression upon Treg restimulation in the absence of exogenous TGF-β1. Consistently, DEL-1 enhanced the demethylation of the Treg-specific demethylated region (TSDR) in the mouse Foxp3 gene and the suppressive function of sorted induced Tregs. Similarly, DEL-1 increased RUNX1 and FOXP3 expression in human conventional T cells, promoting their conversion into induced Tregs with increased TSDR demethylation, enhanced stability, and suppressive activity. We thus uncovered a DEL-1/αvβ3/RUNX1 axis that promotes Treg responses at barrier sites and offers therapeutic options for modulating inflammatory/autoimmune disorders.

Idiopathic pulmonary fibrosis (IPF) is a chronic and fatal disease of unknown etiology; however, apoptosis of lung alveolar epithelial cells plays a role in disease progression. This intractable disease is associated with increased abundance of Staphylococcus and Streptococcus in the lungs, yet their roles in disease pathogenesis remain elusive. Here, we report that Staphylococcus nepalensis releases corisin, a peptide conserved in diverse staphylococci, to induce apoptosis of lung epithelial cells. The disease in mice exhibits acute exacerbation after intrapulmonary instillation of corisin or after lung infection with corisin-harboring S. nepalensis compared to untreated mice or mice infected with bacteria lacking corisin. Correspondingly, the lung corisin levels are significantly increased in human IPF patients with acute exacerbation compared to patients without disease exacerbation. Our results suggest that bacteria shedding corisin are involved in acute exacerbation of IPF, yielding insights to the molecular basis for the elevation of staphylococci in pulmonary fibrosis. Idiopathic pulmonary fibrosis is associated with increased abundance of Staphylococcus and Streptococcus in the lungs. Here, the authors identify a Staphylococcus nepalensis -derived peptide, named corisin, to induce apoptosis of lung epithelial cells and exacerbation of pulmonary fibrosis in mice.

Older adults have decreased vaccine efficacy, but the adjuvanted recombinant VZV-gE zoster vaccine (RZV) is highly efficacious. We investigated memory-like innate immune responses after RZV and after the zoster vaccine live (ZVL), which is much less efficacious. RZV increased NK, monocyte, and DC activation in response to in vitro VZV-gE stimulation for up to 5 years post-vaccination, while ZVL increased only DC responses to VZV for up to 90 days. In purified monocyte and NK cell cocultures, RZV recipients showed increased responses to VZV-gE, HCMV and HSV antigenic stimulation post-vaccination. ATAC-seq analysis of purified monocytes revealed decreased accessibility in areas of the TGFβ1 gene. scRNA-seq and immunoproteomics confirmed decreased TGFβ1 transcription and translation, respectively. Exogenous supplementation and inhibition of TGFβ1 modulated in vitro monocyte responses to VZV-gE. In conclusion, RZV generated homologous (VZV-gE) and heterologous (HCMV, HSV) trained immunity in monocytes through genomic repression of the regulatory cytokine TGFβ-1. Cytokine modulation may represent a novel mechanism of generating trained immunity in myeloid cells.