Increased T Cell Plasticity With Dysregulation of Follicular Helper T, Peripheral Helper T, and Treg Cell Responses in Children With Juvenile Idiopathic Arthritis and Down Syndrome-Associated Arthritis.

OBJECTIVE: Juvenile idiopathic arthritis (JIA) is the most common inflammatory arthritis in children; however, an aggressive, erosive arthritis of little-known immunologic mechanism occurs 20 times more frequently in children with Down syndrome. This study was undertaken to characterize T cell and B cell polyreactivity, follicular helper T (Tfh) cell, peripheral helper T (Tph) cell, and Treg cell responses, and synovial inflammation in Down syndrome-associated arthritis (DA). METHODS: Multiparametric flow cytometric analysis and Simplified Presentation of Incredibly Complex Evaluations (SPICE) software were used to examine peripheral blood B cell populations and T cell cytokine responses in patients with DA, JIA, Down syndrome (trisomy 21 [T21]), and in healthy controls. Tfh and Tph cell frequency and origin, in addition to Treg cell frequency, were also evaluated. Synovial inflammation was assessed by immunohistology. RESULTS: Expansion of IgM-only memory B cells was demonstrated in DA compared to JIA (mean ± SEM 22.48 ± 3.278 versus 9.011 ± 1.317; P = 0.005), paralleled by decreased frequency of transitional B cells. T cell responses in DA were characterized by marked functional plasticity, as was evident from the increased frequency of polyfunctional CD8+ Th cells (P < 0.05), CD161+ Th cells (P < 0.05), and CD8- Th cells (P < 0.001), and positivity for tumor necrosis factor, interferon-γ, interleukin-17A, or granulocyte-macrophage colony-stimulating factor, compared to all other groups. Significant expansion of CXCR3+CCR6+ (Th1/Th17) Tfh cells (P = 0.003) and CXCR3+CCR6+ Tph cells (P = 0.01), paralleled by a decrease in CXCR3-CCR6- (Th2) Tfh cells was observed in DA compared to T21. Treg cells were significantly reduced in DA compared to T21 (mean ± SEM 7.111 ± 0.9518 versus 11.96 ± 1.055 versus; P = 0.0028), with a specific reduction in the naive:memory Treg cell ratio. Marked synovial tissue inflammation and increased T cell and B cell infiltrations were demonstrated in DA compared to JIA. CONCLUSION: DA is more common and more aggressive than JIA. It is characterized by increased polyreactive Th, Tfh, and Tph cell responses, reduced Treg cell frequency, and evidence of increased synovial inflammation, all of which are potentially distinct from JIA and T21.

Changes in mitochondrial stability during the progression of the Barrett's esophagus disease sequence.

BACKGROUND: Barrett's esophagus follows the classic step-wise progression of metaplasia-dysplasia-adenocarcinoma. While Barrett's esophagus is a leading known risk factor for esophageal adenocarcinoma, the pathogenesis of this disease sequence is poorly understood. Mitochondria are highly susceptible to mutations due to high levels of reactive oxygen species (ROS) coupled with low levels of DNA repair. The timing and levels of mitochondria instability and dysfunction across the Barrett's disease progression is under studied. METHODS: Using an in-vitro model representing the Barrett's esophagus disease sequence of normal squamous epithelium (HET1A), metaplasia (QH), dysplasia (Go), and esophageal adenocarcinoma (OE33), random mitochondrial mutations, deletions and surrogate markers of mitochondrial function were assessed. In-vivo and ex-vivo tissues were also assessed for instability profiles. RESULTS: Barrett's metaplastic cells demonstrated increased levels of ROS (p < 0.005) and increased levels of random mitochondrial mutations (p < 0.05) compared with all other stages of the Barrett's disease sequence in-vitro. Using patient in-vivo samples, Barrett's metaplasia tissue demonstrated significantly increased levels of random mitochondrial deletions (p = 0.043) compared with esophageal adenocarcinoma tissue, along with increased expression of cytoglobin (CYGB) (p < 0.05), a gene linked to oxidative stress, compared with all other points across the disease sequence. Using ex-vivo Barrett's metaplastic and matched normal patient tissue explants, higher levels of cytochrome c (p = 0.003), SMAC/Diablo (p = 0.008) and four inflammatory cytokines (all p values <0.05) were secreted from Barrett's metaplastic tissue compared with matched normal squamous epithelium. CONCLUSIONS: We have demonstrated that increased mitochondrial instability and markers of cellular and mitochondrial stress are early events in the Barrett's disease sequence.

Dysregulated bioenergetics: a key regulator of joint inflammation.

OBJECTIVES: This study examines the relationship between synovial hypoxia and cellular bioenergetics with synovial inflammation. METHODS: Primary rheumatoid arthritis synovial fibroblasts (RASF) were cultured with hypoxia, dimethyloxalylglycine (DMOG) or metabolic intermediates. Mitochondrial respiration, mitochondrial DNA mutations, cell invasion, cytokines, glucose and lactate were quantified using specific functional assays. RASF metabolism was assessed by the XF24-Flux Analyzer. Mitochondrial structural morphology was assessed by transmission electron microscopy (TEM). In vivo synovial tissue oxygen (tpO2 mmHg) was measured in patients with inflammatory arthritis (n=42) at arthroscopy, and markers of glycolysis/oxidative phosphorylation (glyceraldehyde 3-phosphate dehydrogenase (GAPDH), PKM2, GLUT1, ATP) were quantified by immunohistology. A subgroup of patients underwent contiguous MRI and positron emission tomography (PET)/CT imaging. RASF and human dermal microvascular endothelial cells (HMVEC) migration/angiogenesis, transcriptional activation (HIF1α, pSTAT3, Notch1-IC) and cytokines were examined in the presence of glycolytic inhibitor 3-(3-Pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3PO). RESULTS: DMOG significantly increased mtDNA mutations, mitochondrial membrane potential, mitochondrial mass, reactive oxygen species and glycolytic RASF activity with concomitant attenuation of mitochondrial respiration and ATP activity (all p<0.01). This was coupled with altered mitochondrial morphology. Hypoxia-induced lactate levels (p<0.01), which in turn induced basic fibroblast growth factor (bFGF) secretion and RASF invasiveness (all p<0.05). In vivo glycolytic markers were inversely associated with synovial tpO2 levels <20 mm Hg, in contrast ATP was significantly reduced (all p<0.05). Decrease in GAPDH and GLUT1 was paralleled by an increase in in vivo tpO2 in tumour necrosis factor alpha inhibitor (TNFi) responders. Novel PET/MRI hybrid imaging demonstrated close association between metabolic activity and inflammation. 3PO significantly inhibited RASF invasion/migration, angiogenic tube formation, secretion of proinflammatory mediators (all p<0.05), and activation of HIF1α, pSTAT3 and Notch-1IC under normoxic and hypoxic conditions. CONCLUSIONS: Hypoxia alters cellular bioenergetics by inducing mitochondrial dysfunction and promoting a switch to glycolysis, supporting abnormal angiogenesis, cellular invasion and pannus formation.

Synovial tissue hypoxia and inflammation in vivo.

INTRODUCTION: Hypoxia is a microenvironmental feature in the inflamed joint, which promotes survival advantage for cells. The aim of this study was to examine the relationship of partial oxygen pressure in the synovial tissue (tPO(2)) in patients with inflammatory arthritis with macroscopic/microscopic inflammation and local levels of proinflammatory mediators. METHODS: Patients with inflammatory arthritis underwent full clinical assessment and video arthroscopy to quantify macroscopic synovitis and measure synovial tPO(2) under direct visualisation. Cell specific markers (CD3 (T cells), CD68 (macrophages), Ki67 (cell proliferation) and terminal deoxynucleotidyl transferase dUTP nick end labelling (cell apoptosis)) were quantified by immunohistology. In vitro migration was assessed in primary and normal synoviocytes (synovial fibroblast cells (SFCs)) using a wound repair scratch assay. Levels of tumour necrosis factor alpha (TNFalpha), interleukin 1beta (IL1beta), interferon gamma (IFNgamma), IL6, macrophage inflammatory protein 3alpha (MIP3alpha) and IL8 were quantified, in matched serum and synovial fluid, by multiplex cytokine assay and ELISA. RESULTS: The tPO(2) was 22.5 (range 3.2-54.1) mm Hg and correlated inversely with macroscopic synovitis (r=-0.421, p=0.02), sublining CD3 cells (-0.611, p<0.01) and sublining CD68 cells (r=-0.615, p<0.001). No relationship with cell proliferation or apoptosis was found. Primary and normal SFCs exposed to 1% and 3% oxygen (reflecting the median tPO(2) in vivo) induced cell migration. This was coupled with significantly higher levels of synovial fluid tumour necrosis factor alpha (TNFalpha), IL1beta, IFNgamma and MIP3alpha in patients with tPO(2) <20 mm Hg (all p values <0.05). CONCLUSIONS: This is the first study to show a direct in vivo correlation between synovial tPO(2), inflammation and cell migration, thus it is proposed that hypoxia is a possible primary driver of inflammatory processes in the arthritic joint.

Research on heterocyclic compounds. XV. Substitution influence on the pharmacological activity in a series of imidazo[1,2-a]pyridines.

We have taken into consideration a group of 28 imidazo [1,2-a]pyridine derivatives, some of which were already known, whereas the others have been synthesized and characterized to complete the series. Antiinflammatory, analgesic, antipyretic and ulcerogenic activities of such compounds were evaluated in comparison with indomethacin. The pharmacological data demonstrated the effects exerted on activity by the presence on the heterocyclic system of methyl substituents and/or an acidic moiety.