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Toll-like receptor 3 L412F polymorphism promotes a persistent clinical phenotype in pulmonary sarcoidosis.

ABSTRACT: Background/Introduction:Sarcoidosis is a multi-systemic disorder of unknown etiology, characterized by the presence of non-caseating granulomas in target organs. In 90% of cases, there is thoracic involvement. Fifty to seventy percent of pulmonary sarcoidosis patients will experience acute, self-limiting disease. For the subgroup of patients who develop persistent disease, no targeted therapy is currently available. Aim:To investigate the potential of the single nucleotide polymorphism (SNP), Toll-like receptor 3 Leu412Phe (TLR3 L412F; rs3775291), as a causative factor in the development of and in disease persistence in pulmonary sarcoidosis. To investigate the functionality of TLR3 L412F in vitro in primary human lung fibroblasts from pulmonary sarcoidosis patients. Design:SNP-genotyping and cellular assays, respectively, were used to investigate the role of TLR3 L412F in the development of persistent pulmonary sarcoidosis. Methods:Cohorts of Irish sarcoidosis patients (n?=?228), healthy Irish controls (n?=?263) and a secondary cohort of American sarcoidosis patients (n?=?123) were genotyped for TLR3 L412F. Additionally, the effect of TLR3 L412F in primary lung fibroblasts from pulmonary sarcoidosis patients was quantitated following TLR3 activation in the context of cytokine and type I interferon production, TLR3 expression and apoptotic- and fibroproliferative-responses. Results:We report a significant association between TLR3 L412F and persistent clinical disease in two cohorts of Irish and American Caucasians with pulmonary sarcoidosis. Furthermore, activation of TLR3 in primary lung fibroblasts from 412?F-homozygous pulmonary sarcoidosis patients resulted in reduced IFN-? and TLR3 expression, reduced apoptosis- and dysregulated fibroproliferative-responses compared with TLR3 wild-type patients. Discussion/Conclusion:This study identifies defective TLR3 function as a previously unidentified factor in persistent clinical disease in pulmonary sarcoidosis and reveals TLR3 L412F as a candidate biomarker.

SUBMITTER: Cooke G

PROVIDER: S-EPMC6256937 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature

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Toll-like receptor 3 L412F polymorphism promotes a persistent clinical phenotype in pulmonary sarcoidosis.

Cooke G G Kamal I I Strengert M M Hams E E Mawhinney L L Tynan A A O'Reilly C C O'Dwyer D N DN Kunkel S L SL Knaus U G UG Shields D C DC Moller D R DR Bowie A G AG Fallon P G PG Hogaboam C M CM Armstrong M E ME Donnelly S C SC

QJM : monthly journal of the Association of Physicians 20180401 4

<h4>Background/introduction</h4>Sarcoidosis is a multi-systemic disorder of unknown etiology, characterized by the presence of non-caseating granulomas in target organs. In 90% of cases, there is thoracic involvement. Fifty to seventy percent of pulmonary sarcoidosis patients will experience acute, self-limiting disease. For the subgroup of patients who develop persistent disease, no targeted therapy is currently available.<h4>Aim</h4>To investigate the potential of the single nucleotide polymor ...[more]

PMID: 29237089

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Project description:BackgroundMacrophages are pivotal cells in sarcoidosis. Monocytes-derived (MD) macrophages have recently been demonstrated to play a major role especially in pulmonary sarcoidosis. From inflammatory tissues to granulomas, they may be exposed to low oxygen tension environments. As hypoxia impact on sarcoidosis immune cells has never been addressed, we designed the present study to investigate MD-macrophages from sarcoidosis patients in this context. We hypothesized that hypoxia may induce functional changes on MD-macrophages which could have a potential impact on the course of sarcoidosis.MethodsWe studied MD-macrophages, from high active sarcoidosis (AS) (n=26), low active or inactive sarcoidosis (IS) (n=24) and healthy controls (n=34) exposed 24 hours to normoxia (21% O2) or hypoxia (1.5% O2). Different macrophage functions were explored: hypoxia-inducible factor-1α (HIF-1α) and nuclear factor-kappa B (NF-κB) activation, cytokines secretion, phagocytosis, CD80/CD86/HLA-DR expression, profibrotic response.ResultsWe observed that hypoxia, with a significantly more pronounced effect in AS compared with controls and IS, increased the HIF-1α trans-activity, promoted a proinflammatory response (TNFα, IL1ß) without activating NF-κB pathway and a profibrotic response (TGFß1, PDGF-BB) with PAI-1 secretion associated with human lung fibroblast migration inhibition. These results were confirmed by immunodetection of HIF-1α and PAI-1 in granulomas observed in pulmonary biopsies from patients with sarcoidosis. Hypoxia also decreased the expression of CD80/CD86 and HLA-DR on MD-macrophages in the three groups while it did not impair phagocytosis and the expression of CD36 expression on cells in AS and IS at variance with controls.ConclusionsHypoxia had a significant impact on MD-macrophages from sarcoidosis patients, with the strongest effect seen in patients with high active disease. Therefore, hypoxia could play a significant role in sarcoidosis pathogenesis by increasing the macrophage proinflammatory response, maintaining phagocytosis and reducing antigen presentation, leading to a deficient T cell response. In addition, hypoxia could favor fibrosis by promoting profibrotic cytokines response and by sequestering fibroblasts in the vicinity of granulomas.

Project description:RationaleThe critical innate immune mechanisms that regulate granulomatous inflammation in sarcoidosis are unknown. Because the granuloma-inducing component of sarcoidosis tissues has physicochemical properties similar to those of amyloid fibrils, we hypothesized that host proteins capable of forming poorly soluble aggregates or amyloid regulate inflammation in sarcoidosis.ObjectivesTo determine the role of the amyloid precursor protein, serum amyloid A, as an innate regulator of granulomatous inflammation in sarcoidosis.MethodsSerum amyloid A expression was determined by immunohistochemistry in sarcoidosis and control tissues and by ELISA. The effect of serum amyloid A on nuclear factor (NF)-kappaB induction, cytokine expression, and Toll-like receptor-2 stimulation was determined with transformed human cell lines and bronchoalveolar lavage cells from patients with sarcoidosis. The effects of serum amyloid A on regulating helper T cell type 1 (Th1) granulomatous inflammation were determined in experimental models of sarcoidosis, using Mycobacterium tuberculosis catalase-peroxidase.Measurements and main resultsWe found that the intensity of expression and distribution of serum amyloid A within sarcoidosis granulomas was unlike that in many other granulomatous diseases. Serum amyloid A localized to macrophages and giant cells within sarcoidosis granulomas but correlated with CD3(+) lymphocytes, linking expression to local Th1 responses. Serum amyloid A activated NF-kappaB in Toll-like receptor-2-expressing human cell lines; regulated experimental Th1-mediated granulomatous inflammation through IFN-gamma, tumor necrosis factor, IL-10, and Toll-like receptor-2; and stimulated production of tumor necrosis factor, IL-10, and IL-18 in lung cells from patients with sarcoidosis, effects inhibited by blocking Toll-like receptor-2.ConclusionsSerum amyloid A is a constituent and innate regulator of granulomatous inflammation in sarcoidosis through Toll-like receptor-2, providing a mechanism for chronic disease and new therapeutic targets.

Project description:PurposeReduced physical activity in many chronic diseases is consistently associated with increased morbidity. Little is known about physical activity in sarcoidosis. The aim of this study was to objectively assess physical activity in patients with pulmonary sarcoidosis and investigate its relationship with lung function, exercise capacity, symptom burden, and health status.MethodsPhysical activity was assessed over one week in 15 patients with pulmonary sarcoidosis and 14 age-matched healthy controls with a tri-axial accelerometer (ActivPal™) and the International Physical Activity Questionnaire (IPAQ). All participants underwent pulmonary function tests, 6-min walk test (6MWT) and completed the Fatigue Assessment Scale (FAS), Medical Research Council (MRC) Dyspnoea Scale and the King's Sarcoidosis Questionnaire (KSQ).ResultsPatients with sarcoidosis had significantly lower daily step counts than healthy controls; mean (SD) 5624 (1875) versus 10,429 (2942) steps (p?<?0.01) and a trend towards fewer sit-to-stand transitions each day (p?=?0.095). Only two patients (13%) self-reported undertaking vigorous physical activity (IPAQ) compared to half of healthy individuals (p?<?0.01). Daily step count was significantly associated with 6MWT distance in sarcoidosis (r?=?0.634, p?=?0.01), but not with forced vital capacity (r?=?0.290), fatigue (r?=?0.041), dyspnoea (r?=?-0.466) or KSQ health status (r?=?0.099-0.484). Time spent upright was associated with fatigue (r?=?-0.630, p?=?0.012) and health status (KSQ Lung scores r?=?0.524, p?=?0.045), and there was a significant correlation between the number of sit-to-stand transitions and MRC dyspnoea score (r?=?-0.527, p?=?0.044).ConclusionPhysical activity is significantly reduced in sarcoidosis and is associated with reduced functional exercise capacity (6MWD). Fatigue, exertional symptoms and health status were more closely associated with time spent upright and the number of bouts of physical activity, as compared to step counts. Further studies are warranted to identify the factors that determine different physical activity profiles in sarcoidosis.

Dataset Information

Toll-like receptor 3 L412F polymorphism promotes a persistent clinical phenotype in pulmonary sarcoidosis.

Publications

Toll-like receptor 3 L412F polymorphism promotes a persistent clinical phenotype in pulmonary sarcoidosis.

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