Interleukin-17A is not expressed by CD207(+) cells in Langerhans cell histiocytosis lesions.
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ABSTRACT:
SUBMITTER: Allen CE
PROVIDER: S-EPMC2820828 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Langerhans cell histiocytosis (LCH) is a complex and poorly understood disorder that has characteristics of both inflammatory and neoplastic disease. By using eight-colour flow cytometry, we have identified a previously unreported population of CD1a(+)/CD3(+) T-cells in LCH lesions. The expression of CD1a is regarded as a hallmark of this disease; however, it has always been presumed that it was only expressed by pathogenic Langerhans cells (LCs). We have now detected CD1a expression by a range of T-cell subsets within all of the LCH lesions that were examined, establishing that CD1a expression in these lesions is no longer restricted to pathogenic LCs. The presence of CD1a(+) T-cells in all of the LCH lesions that we have studied to date warrants further investigation into their biological function to determine whether these cells are important in the pathogenesis of LCH.
| S-EPMC4208746 | biostudies-literature
Project description:Langerhans cell histiocytosis (LCH) is a rare disease characterized by heterogeneous lesions containing CD207(+) Langerhans cells (LCs) and lymphocytes that can arise in almost any tissue and cause significant morbidity and mortality. After decades of research, the cause of LCH remains speculative. A prevailing model suggests that LCH arises from malignant transformation and metastasis of epidermal LCs. In this study, CD207(+) cells and CD3(+) T cells were isolated from LCH lesions to determine cell-specific gene expression. Compared with control epidermal CD207(+) cells, the LCH CD207(+) cells yielded 2113 differentially expressed genes (false discovery rate < 0.01). Surprisingly, the expression of many genes previously associated with LCH, including cell-cycle regulators, proinflammatory cytokines, and chemokines, were not significantly different from control LCs in our study. However, several novel genes whose products activate and recruit T cells to sites of inflammation, including SPP1 (osteopontin), were highly overexpressed in LCH CD207(+) cells. Furthermore, several genes associated with immature myeloid dendritic cells were overexpressed in LCH CD207(+) cells. Compared with the peripheral CD3(+) cells from LCH patients, the LCH lesion CD3(+) cells yielded only 162 differentially regulated genes (false discovery rate < 0.01), and the expression profile of the LCH lesion CD3(+) cells was consistent with an activated regulatory T cell phenotype with increased expression of FOXP3, CTLA4, and SPP1. Results from this study support a model of LCH pathogenesis in which lesions do not arise from epidermal LCs but from accumulation of bone marrow-derived immature myeloid dendritic cells that recruit activated lymphocytes.
| S-EPMC3142675 | biostudies-literature
Project description: Not available
| S-EPMC6334777 | biostudies-literature
Project description:Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasm characterised by the accumulation into granulomas of apoptosis-resistant pathological dendritic cells (LCH-DCs). LCH outcome ranges from self-resolving to fatal. Having previously shown that, (i) monocyte-derived DCs (Mo-DCs) from LCH patients differentiate into abnormal and pro-inflammatory IL-17A-producing DCs, and (ii) recombinant IL-17A induces survival and chemoresistance of healthy Mo-DCs, we investigated the link between IL-17A and resistance to apoptosis of LCH-DCs. In LCH granulomas, we uncovered the strong expression of BCL2A1 (alias BFL1), an anti-apoptotic BCL2 family member. In vitro, intracellular IL-17A expression was correlated with BCL2A1 expression and survival of Mo-DCs from LCH patients. Based on the chemotherapeutic drugs routinely used as first or second line LCH therapy, we treated these cells with vinblastine, or cytarabine and cladribine. Our preclinical results indicate that high doses of these drugs decreased the expression of Mcl-1, the main anti-apoptotic BCL2 family member for myeloid cells, and killed Mo-DCs from LCH patients ex vivo, without affecting BCL2A1 expression. Conversely, neutralizing anti-IL-17A antibodies decreased BCL2A1 expression, the downregulation of which lowered the survival rate of Mo-DCs from LCH patients. Interestingly, the in vitro combination of low-dose vinblastine with neutralizing anti-IL-17A antibodies killed Mo-DCs from LCH patients. In conclusion, we show that BCL2A1 expression induced by IL-17A links the inflammatory environment to the unusual pro-survival gene activation in LCH-DCs. Finally, these preclinical data support that targeting both Mcl-1 and BCL2A1 with low-dose vinblastine and anti-IL-17A biotherapy may represent a synergistic combination for managing recurrent or severe forms of LCH.
| S-EPMC8814633 | biostudies-literature
Project description:Expression data from LCH lesion subpopulations and healthy donors' peripheral blood specimens Langerhans cell histiocytosis (LCH) is a myeloproliferative disorder that is characterized by the inflammatory lesions with pathogenic CD1a+CD207+ dendritic cells (DCs). BRAFV600E and other somatic activating MAPK gene mutations have been identified in differentiating bone marrow and blood myeloid cells, but the origin of the LCH lesion CD1a+CD207+DCs and mechanisms of lesion formation remain incompletely defined. In order to identify candidate LCH CD1a+CD207+DCs’ precursor populations, gene expression profiles of LCH lesion CD1a+CD207+DCs were first compared to established gene signatures from human myeloid cell subpopulations. Interestingly, the CD1c+ myeloid DC (mDC) gene signature was most enriched in the LCH CD1a+CD207+DC’ transcriptome. Additionally, the BRAFV600E allele was not only localized to CD1a+CD207-DCs and CD1a+CD207+DCs, but it was also identified in CD1c+mDCs in LCH lesions. Transcriptomes of CD1a+CD207-DCs were nearly indistinguishable from CD1a+CD207+DCs (both CD207low and CD207high subpopulations). Transcription profiles of LCH lesion CD1a+CD207+DCs and peripheral blood CD1c+mDCs from healthy donors were compared to identify potential LCH DC-specific biomarkers. HLADQB2 expression was significantly increased in LCH lesion CD1a+CD207+DCs compared to circulating CD1c+mDCs from healthy donors, and HLA-DQB2 antigen was identified on LCH lesion CD1a+CD207- and CD1a+CD207+DCs as well as on CD1c+(CD1a+CD207-) mDCs, but not in any other lesion myeloid subpopulations. Interestingly, HLADQB2 expression was specific to peripheral blood of patients with BRAFV600E+ peripheral blood mononuclear cells (PBMC), and HLA-DQB2+CD1c+blood cells were highly enriched for the BRAFV600E in these patients. These data support a model where blood CD1c+mDCs with activated ERK migrate to lesion sites where they differentiate into pathogenic CD1a+CD207+ DCs.
2020-01-21 | GSE122476 | GEO
Project description:Expression data from LCH lesion subpopulations and healthy donors' peripheral blood specimens Langerhans cell histiocytosis (LCH) is a myeloproliferative disorder that is characterized by the inflammatory lesions with pathogenic CD1a+CD207+ dendritic cells (DCs). BRAFV600E and other somatic activating MAPK gene mutations have been identified in differentiating bone marrow and blood myeloid cells, but the origin of the LCH lesion CD1a+CD207+DCs and mechanisms of lesion formation remain incompletely defined. In order to identify candidate LCH CD1a+CD207+DCs’ precursor populations, gene expression profiles of LCH lesion CD1a+CD207+DCs were first compared to established gene signatures from human myeloid cell subpopulations. Interestingly, the CD1c+ myeloid DC (mDC) gene signature was most enriched in the LCH CD1a+CD207+DC’ transcriptome. Additionally, the BRAFV600E allele was not only localized to CD1a+CD207-DCs and CD1a+CD207+DCs, but it was also identified in CD1c+mDCs in LCH lesions. Transcriptomes of CD1a+CD207-DCs were nearly indistinguishable from CD1a+CD207+DCs (both CD207low and CD207high subpopulations). Transcription profiles of LCH lesion CD1a+CD207+DCs and peripheral blood CD1c+mDCs from healthy donors were compared to identify potential LCH DC-specific biomarkers. HLADQB2 expression was significantly increased in LCH lesion CD1a+CD207+DCs compared to circulating CD1c+mDCs from healthy donors, and HLA-DQB2 antigen was identified on LCH lesion CD1a+CD207- and CD1a+CD207+DCs as well as on CD1c+(CD1a+CD207-) mDCs, but not in any other lesion myeloid subpopulations. Interestingly, HLADQB2 expression was specific to peripheral blood of patients with BRAFV600E+ peripheral blood mononuclear cells (PBMC), and HLA-DQB2+CD1c+blood cells were highly enriched for the BRAFV600E in these patients. These data support a model where blood CD1c+mDCs with activated ERK migrate to lesion sites where they differentiate into pathogenic CD1a+CD207+ DCs.
2020-01-21 | GSE122674 | GEO
Project description:Children with Langerhnans cell histiocytosis (LCH) develop granulomatous lesions with characteristic clonal CD207+ dendritic cells that can arise as single lesions or life-threatening disseminated disease. Despite the wide range of clinical presentations, LCH lesions are histologically indistinguishable based on severity of disease, and uncertain classification as an immune versus neoplastic disorder has historically challenged the development of optimal clinical strategies for patients with LCH. Recently, activating somatic mutations in MAPK pathway genes, most notably BRAFV600E, have been discovered in almost all cases of LCH. Further, the stage of myeloid differentiation in which the mutation arises defines the extent of disease and risk of developing LCH-associated neurodegeneration. MAPK activation in LCH precursor cells drives myeloid differentiation, inhibits migration, and inhibits apoptosis, resulting in accumulation of resilient pathologic dendritic cells that recruit and activate T cells. Recurrent somatic mutations in MAPK pathway genes have also been identified in related histiocytic disorders: juvenile xanthogranuloma, Erdheim-Chester disease, and Rosai-Dorfman disease. New insights into pathogenesis support reclassification of these conditions as a myeloid neoplastic disorders. Continued research will uncover opportunities to identify novel targets and inform personalized therapeutic strategies based on cell of origin, somatic mutation, inherited risk factors, and residual disease.
| S-EPMC9150752 | biostudies-literature
Project description:BackgroundCentral nervous system Langerhans cell histiocytosis (CNS-LCH) brain involvement may include mass lesions and/or a neurodegenerative disease (LCH-ND) of unknown etiology. The goal of this study was to define the mechanisms of pathogenesis that drive CNS-LCH.MethodsCerebrospinal fluid (CSF) biomarkers including CSF proteins and extracellular BRAFV600E DNA were analyzed in CSF from patients with CNS-LCH lesions compared with patients with brain tumors and other neurodegenerative conditions. Additionally, the presence of BRAFV600E was tested in peripheral mononuclear blood cells (PBMCs) as well as brain biopsies from LCH-ND patients, and the response to BRAF-V600E inhibitor was evaluated in 4 patients with progressive disease.ResultsOsteopontin was the only consistently elevated CSF protein in patients with CNS-LCH compared with patients with other brain pathologies. BRAFV600E DNA was detected in CSF of only 2/20 (10%) cases, both with LCH-ND and active lesions outside the CNS. However, BRAFV600E+ PBMCs were detected with significantly higher frequency at all stages of therapy in LCH patients who developed LCH-ND. Brain biopsies of patients with LCH-ND demonstrated diffuse perivascular infiltration by BRAFV600E+ cells with monocyte phenotype (CD14+ CD33+ CD163+ P2RY12- ) and associated osteopontin expression. Three of 4 patients with LCH-ND treated with BRAF-V600E inhibitor experienced significant clinical and radiologic improvement.ConclusionIn LCH-ND patients, BRAFV600E+ cells in PBMCs and infiltrating myeloid/monocytic cells in the brain is consistent with LCH-ND as an active demyelinating process arising from a mutated hematopoietic precursor from which LCH lesion CD207+ cells are also derived. Therapy directed against myeloid precursors with activated MAPK signaling may be effective for LCH-ND. Cancer 2018;124:2607-20. © 2018 American Cancer Society.
| S-EPMC6289302 | biostudies-literature
Project description:Pulmonary Langerhans cell (LC) histiocytosis (PLCH) has unknown cause and is a rare neoplastic disorder characterized by the infiltration of lungs and various organs by bone marrow-derived Langerhans cells with an accompanying strong inflammatory response. These cells carry somatic mutations of BRAF gene and/or NRAS, KRAS, and MAP2K1 genes, which cause activation of the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) signaling pathway. PLCH occurs predominantly in young smokers, without gender predominance. Lungs might be involved as an isolated organ or as part of a multiorgan disease. High-resolution computed chest tomography plays an outstanding role in PLCH diagnosis. The typical radiological picture of PLCH is the presence of small intralobular nodules, "tree in bud" opacities, cavitated nodules, and thin- and thick-walled cysts, frequently confluent. Histological examination of the lesion and demonstration of characteristic eosinophilic granulomas with the presence of LCs that display antigen CD1a or CD207 in immunohistochemistry are required for definite diagnosis. Smoking cessation is the most important recommendation for PLCH patients, but treatment of progressive PLCH and multisystem disease is based on chemotherapy. Recently, new targeted therapies have been implemented.
| S-EPMC7982411 | biostudies-literature
Project description:Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasia characterized by granulomatous lesions containing pathological CD207+ dendritic cells (DCs) with constitutively activated mitogen-activated protein kinase (MAPK) pathway signaling. Approximately 60% of LCH patients harbor somatic BRAFV600E mutations localizing to CD207+ DCs within lesions. However, the mechanisms driving BRAFV600E+ LCH cell accumulation in lesions remain unknown. Here we show that sustained extracellular signal-related kinase activity induced by BRAFV600E inhibits C-C motif chemokine receptor 7 (CCR7)-mediated DC migration, trapping DCs in tissue lesions. Additionally, BRAFV600E increases expression of BCL2-like protein 1 (BCL2L1) in DCs, resulting in resistance to apoptosis. Pharmacological MAPK inhibition restores migration and apoptosis potential in a mouse LCH model, as well as in primary human LCH cells. We also demonstrate that MEK inhibitor-loaded nanoparticles have the capacity to concentrate drug delivery to phagocytic cells, significantly reducing off-target toxicity. Collectively, our results indicate that MAPK tightly suppresses DC migration and augments DC survival, rendering DCs in LCH lesions trapped and resistant to cell death.
| S-EPMC5748846 | biostudies-literature