Deficiency of immunoregulatory indoleamine 2,3-dioxygenase 1 in juvenile diabetes

A defect in indoleamine 2,3-dioxygenase 1 (IDO1), which is responsible for immunoregulatory tryptophan catabolism, impairs development of immune tolerance to autoantigens in NOD mice, a model for human autoimmune type 1 diabetes (T1D). Whether IDO1 function is also defective in T1D is still unknown. We investigated IDO1 function in sera and peripheral blood mononuclear cells (PBMCs) from children with T1D and matched controls. These children were further included in a discovery study to identify SNPs in IDO1 that might modify the risk of T1D. T1D in children was characterized by a remarkable defect in IDO1 function. A common haplotype, associated with dysfunctional IDO1, increased the risk of developing T1D in the discovery and also confirmation studies. In T1D patients sharing such a common IDO1 haplotype, incubation of PBMCs in vitro with tocilizumab (TCZ) - an IL-6 receptor blocker - would, however, rescue IDO1 activity. In an experimental setting with diabetic NOD mice, TCZ was found to restore normoglycemia via IDO1-dependent mechanisms. Thus, functional SNPs of IDO1 are associated with defective tryptophan catabolism in human T1D, and maneuvers aimed at restoring IDO1 function would be therapeutically effective in at least a subgroup of T1D pediatric patients.The authors wish to thank patients and subjects who participated in this study, as well as nurses and staff of the Pediatric Clinic of S. Maria della Misericordia Hospital (Perugia), Juvenile Diabetes Center-Anna Meyer Children's Hospital (Florence), Unit of Endocrinology and Diabetes-'Bambino Gesu' Children's Hospital (Rome), Hopital Necker-Enfants Malades (Paris), and Diabetes and Metabolism Service-University Hospital Centre of Coimbra (Coimbra). The authors wish also to thank Roberto Gerli for the gift of TCZ, Giovanni Ricci for histologies, and Francisco Carrilho and Eduarda Coutinho for providing and processing, respectively, DNA samples from the Portuguese cohorts. This work was supported by the European Research Council (338954-DIDO to UG) and, in part, by Associazione per l'Aiuto ai Giovani con Diabete Italia e dell'Umbria (to UG) and the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER) (NORTE-01-0145-FEDER-000013 to AC) and the Fundacao para a Ciencia e Tecnologia (contracts IF/00735/2014 to AC, and SFRH/BPD/96176/2013 to CC).info:eu-repo/semantics/publishedVersio

The Dichotomous Pattern of IL-12R and IL-23R Expression Elucidates the Role of IL-12 and IL-23 in Inflammation

IL-12 and IL-23 cytokines respectively drive Th1 and Th17 type responses. Yet, little is known regarding the biology of these receptors. As the IL-12 and IL-23 receptors share a common subunit, it has been assumed that these receptors are co-expressed. Surprisingly, we find that the expression of each of these receptors is restricted to specific cell types, in both mouse and human. Indeed, although IL-12Rβ2 is expressed by NK cells and a subset of γδ T cells, the expression of IL-23R is restricted to specific T cell subsets, a small number of B cells and innate lymphoid cells. By exploiting an IL-12- and IL-23-dependent mouse model of innate inflammation, we demonstrate an intricate interplay between IL-12Rβ2 NK cells and IL-23R innate lymphoid cells with respectively dominant roles in the regulation of systemic versus local inflammatory responses. Together, these findings support an unforeseen lineage-specific dichotomy in the in vivo role of both the IL-12 and IL-23 pathways in pathological inflammatory states, which may allow more accurate dissection of the roles of these receptors in chronic inflammatory diseases in humans

High doses of CpG oligodeoxynucleotides stimulate a tolerogenic TLR9–TRIF pathway

CpG-rich oligodeoxynucleotides activate the immune system, leading to innate and acquired immune responses. The immune-stimulatory effects of CpG-rich oligodeoxynucleotides are being exploited as a therapeutic approach. Here we show that at high doses, CpG-rich oligodeoxynucleotides promote an opposite, tolerogenic response in mouse plasmacytoid dendritic cells in vivo and in a human in vitro model. Unveiling a previously undescribed role for TRIF and TRAF6 proteins in Toll-like receptor 9 (TLR9) signalling, we demonstrate that physical association of TLR9, TRIF and TRAF6 leads to activation of noncanonical NF-κB signalling and the induction of IRF3- and TGF-β-dependent immune-suppressive tryptophan catabolism. In vivo, the TLR9-TRIF circuit--but not MyD88 signalling--was required for CpG protection against allergic inflammation. Our findings may be relevant to an increased understanding of the complexity of Toll-like receptor signalling and optimal exploitation of CpG-rich oligodeoxynucleotides as immune modulators

Analysis of the activation profile of dendritic cells derived from the bone marrow of interleukin-12/interleukin-23-deficient mice

We have previously shown that macrophages from interleukin (IL)-12p40 gene knockout (IL-12/IL-23(−/−)) mice have a bias towards the M2 activation profile, spontaneously secreting large quantities of transforming growth factor-β1 (TGF-β1) and producing low levels of nitric oxide (NO) in response to lipopolysaccharide (LPS) and interferon-γ (IFN-γ). To verify whether the activation profile of dendritic cells (DCs) is also influenced by the absence of IL-12/IL-23, bone marrow-derived DCs from IL-12/IL-23(−/−) and C57BL/6 mice were evaluated. At first we noticed that ≈ 50% of the C57BL/6 DCs were dead after LPS-induced maturation, whereas the mortality of IL-12/IL-23(−/−) DCs was < 10%, a protective effect that diminished when recombinant IL-12 (rIL-12) was added during maturation. Similarly to macrophages, mature IL-12/IL-23(−/−) DCs (mDCs) produced higher levels of TGF-β1 and lower levels of NO than C57BL/6 mDCs. NO release was IFN-γ-dependent, as evidenced by the poor response of IFN-γ(−/−) and IL-12/IL-23(−/−)IFN-γ(−/−) mDCs. Nevertheless, IFN-γ deficiency was not the sole reason for the weak NO response observed in the absence of IL-12/IL-23. The high level of TGF-β1 secretion by IL-12/IL-23(−/−) mDCs could explain why exogenous IFN-γ partially restored the NO production of IFN-γ(−/−) mDCs, while IL-12/IL-23(−/−) IFN-γ(−/−) mDCs remained unresponsive. We also showed that CD4(+) T-cell proliferation was inhibited by C57BL/6 mDCs, but not by IL-12/IL-23(−/−) mDCs. IFN-γ and NO appear to mediate this antiproliferative effect because this effect was not observed in the presence of mDCs from IFN-γ(−/−) or IL-12/IL-23(−/−) IFN-γ(−/−) mice and it was attenuated by aminoguanidine. We conclude that the presence of IL-12/IL-23 during LPS-induced maturation influences the activation profile of DCs by a mechanism that is, only in part, IFN-γ dependent

Assessment of TILs, IDO-1, and PD-L1 in resected non-small cell lung cancer: an immunohistochemical study with clinicopathological and prognostic implications

Several cancers, especially non-small cell lung cancer (NSCLC), are able to escape the immunosurveillance of tumor-infiltrating lymphocytes (TILs); among the molecules involved, the indoleamine 2,3-dioxygenase 1 (IDO-1) and the programmed cell death ligand-1 (PD-L1) play a crucial role. These aspects are of great interest in the current immunotherapeutic era, therefore the current study analyses the TILs, IDO-1, and PD-L1 interactions and their correlations with clinicopathological parameters and prognosis in NSCLC. One hundred ninety-three NSCLC surgical specimens, formalin-fixed, and paraffin-embedded were assessed for TILs density, TILs localization, IDO-1 (clone 4.16H1), and PD-L1 (clone E1L3N) immunohistochemical expressions. This data was correlated with clinicopathological parameters, disease free, and overall survivals. IDO-1 and PD-L1 high expressions were related to the solid pattern of adenocarcinomas (respectively p = 0.036 and p = 0.026); high PD-L1 expression was correlated with squamous histotype (p = 0.048). IDO-1 overexpression correlated with former smokers (p = 0.041), higher adenocarcinoma stages (p = 0.039), and with both higher TILs density and PD-L1 expression (respectively p = 0.025 and p = 0.0003). A better prognosis was associated with TILs intratumoral or mixed localizations (p = 0.029). TILs localization affects NSCLC prognosis; the higher expression of IDO-1 and PD-L1 in poorly differentiated and more aggressive lung adenocarcinomas, as well as the correlation between high PD-L1 expression and squamous cell histotype, confirm the more efficient immunoescaping of these NSCLC subgroups