Critical Role of TCF-1 in Repression of the IL-17 Gene

Overwhelming activation of IL-17, a gene involved in inflammation, leads to exaggerated Th17 responses associated with numerous autoimmune conditions, such as experimental autoimmune encephalomyelitis (EAE). Here we show that TCF-1 is a critical factor to repress IL-17 gene locus by chromatin modifications during T cell development. Deletion of TCF-1 resulted in increased IL-17 gene expression both in thymus and peripheral T cells, which led to enhanced Th17 differentiation. As a result, TCF-1-/- mice were susceptible to Th17-dependent EAE induction. Rag1-/- mice reconstituted with TCF-1-/- T cells were also susceptible to EAE, indicating TCF-1 is intrinsically required to repress IL-17. However, expression of wild-type TCF-1 or dominant negative TCF-1 did not interfere with Th17 differentiation in mature T cells. Furthermore, expression of TCF-1 in TCF-1-/- T cells could not restore Th17 differentiation to wild-type levels, indicating that TCF-1 cannot affect IL-17 production at the mature T cell stage. This is also supported by the normal up-regulation or activation in mature TCF-1-/- T cells of factors known to regulate Th17 differentiation, including RORγt and Stat3. We observed hyperacetylation together with trimethylation of Lys-4 at the IL-17 locus in TCF-1-/- thymocytes, two epigenetic modifications indicating an open active state of the gene. Such epigenetic modifications were preserved even when TCF-1-/- T cells migrated out of thymus. Therefore, TCF-1 mediates an active process to repress IL-17 gene expression via epigenetic modifications during T cell development. This TCF-1-mediated repression of IL-17 is critical for peripheral T cells to generate balanced immune responses

Th17 Cells and Activated Dendritic Cells Are Increased in Vitiligo Lesions

Vitiligo is a common skin disorder, characterized by progressive skin de-pigmentation due to the loss of cutaneous melanocytes. The exact cause of melanocyte loss remains unclear, but a large number of observations have pointed to the important role of cellular immunity in vitiligo pathogenesis.In this study, we characterized T cell and inflammation-related dermal dendritic cell (DC) subsets in pigmented non-lesional, leading edge and depigmented lesional vitiligo skin. By immunohistochemistry staining, we observed enhanced populations of CD11c+ myeloid dermal DCs and CD207+ Langerhans cells in leading edge vitiligo biopsies. DC-LAMP+ and CD1c+ sub-populations of dermal DCs expanded significantly in leading edge and lesional vitiligo skin. We also detected elevated tissue mRNA levels of IL-17A in leading edge skin biopsies of vitiligo patients, as well as IL-17A positive T cells by immunohistochemistry and immunofluorescence. Langerhans cells with activated inflammasomes were also noted in lesional vitiligo skin, along with increased IL-1ß mRNA, which suggest the potential of Langerhans cells to drive Th17 activation in vitiligo.These studies provided direct tissue evidence that implicates active Th17 cells in vitiligo skin lesions. We characterized new cellular immune elements, in the active margins of vitiligo lesions (e.g. populations of epidermal and dermal dendritic cells subsets), which could potentially drive the inflammatory responses

Potential immunological consequences of pharmacological suppression of gastric acid production in patients with multiple sclerosis

Corticosteroids are standard treatment for patients with multiple sclerosis experiencing acute relapse. Because dyspeptic pain is a common side effect of this intervention, patients can be given a histamine receptor-2 antagonist, proton pump inhibitor or antacid to prevent or ameliorate this disturbance. Additionally, patients with multiple sclerosis may be taking these medications independent of corticosteroid treatment. Interventions for gastric disturbances can influence the activation state of the immune system, a principal mediator of pathology in multiple sclerosis. Although histamine release promotes inflammation, activation of the histamine receptor-2 can suppress a proinflammatory immune response, and blocking histamine receptor-2 with an antagonist could shift the balance more towards immune stimulation. Studies utilizing an animal model of multiple sclerosis indicate that histamine receptor-2 antagonists potentially augment disease activity in patients with multiple sclerosis. In contrast, proton pump inhibitors appear to favor immune suppression, but have not been studied in models of multiple sclerosis. Antacids, histamine receptor-2 antagonists and proton pump inhibitors also could alter the intestinal microflora, which may indirectly lead to immune stimulation. Additionally, elevated gastric pH can promote the vitamin B12 deficiency that patients with multiple sclerosis are at risk of developing. Here, we review possible roles of gastric acid inhibitors on immunopathogenic mechanisms associated with multiple sclerosis

Foxp3(+) regulatory T cells, Th17 effector cells, and cytokine environment in inflammatory bowel disease

Background: Inflammatory bowel disease (IBD) is thought to result from an aberrant immune response. Inflammation in IBD may be caused by the loss of homeostasis between CD4+ CD25high Foxp3+ regulatory cells (T reg) and proinflammatory Th17 cells. The aim of this study was to investigate T reg and Th17 cells in the peripheral blood and intestinal mucosa of IBD patients and to assess the mucosal cytokine environment. Methods: T reg and Th17 cells were measured in peripheral blood of 63 IBD patients and 28 controls by flow cytometry. Forkhead box p3 (Foxp3), interleukin (IL)-17a, IL-1β, IL-6, IL-21, IL-23, and transforming growth factor (TGF)-β mRNA were analyzed using real-time reverse transcription polymerase chain reaction in intestinal biopsies of 24 IBD and 18 control subjects. Results: A decrease in T reg and increase in Th17 cells was observed in the peripheral blood of IBD patients. When measured in the same patient and expressed as a ratio, a significant decrease in T reg/Th17 ratio was observed in IBD. Elevated expression of Foxp3, IL-17a, IL-1β, and IL-6 was observed in the mucosa of IBD patients, while TGF-β was only elevated in ulcerative colitis. Conclusion: IBD is associated with a reduced ratio of T reg to Th17 cells in peripheral blood and is characterized by a proinflammatory cytokine microenvironment, which supports the continued generation of Th17 cells.Nicola Eastaff-Leung, Nicholas Mabarrack, Angela Barbour, Adrian Cummins and Simon Barr

Metalloproteinases and their tissue inhibitors in multiple sclerosis

Matrix metalloproteinases (MMPs) comprise a family of proteolytic enzymes. MMPs are capable of disrupting the blood-brain barrier (BBB), mediating the destruction of extracellular matrix and myelin components. MMPs are also involved in the processing of a variety of cell surface molecules, including the proinflammatory cytokine TNF-alpha. Each of these mechanisms are thought to be important in the pathogenesis of multiple sclerosis (MS). We investigated mRNA expression of MMP-3, MMP-9 and two tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) in parallel in blood mononuclear cells (MNC) from patients with MS and controls, using in situ hybridization. Numbers of MMP-9 mRNA-expressing cells in blood were higher in patients with MS compared to other neurological diseases (OND), other inflammatory neurological diseases (OIND) and healthy subjects (P<0.0001 for all comparisons). Patients with MS had also higher levels of MMP-3 and TIMP-1 mRNA expressing blood MNC compared to patients with OND and healthy subjects. A positive correlation was observed for MMP-9 and TIMP-1 mRNA expression in MS. These results demonstrate that MMPs and TIMPs are upregulated in MS and may contribute to the pathogenesis of the disease

Blood Pressure after Endovascular Thrombectomy: Modeling for Outcomes Based on Recanalization Status

Background and Purpose-The optimal level for blood pressure after endovascular thrombectomy in acute ischemic stroke is not well established. We sought to evaluate the association of post-endovascular thrombectomy systolic blood pressure (SBP) levels with clinical outcomes. Methods-We included endovascular thrombectomy-treated patients registered from 2014 to 2017 in the Safe Implementation of Treatments in Stroke International Thrombectomy Registry. The mean 24-hour SBP after endovascular thrombectomy treatment was analyzed both as a continuous variable and in intervals. The primary outcome was 3-month functional independence (modified Rankin Scale score of 0-2). The secondary outcomes were symptomatic intracerebral hemorrhage (SICH) and 3-month mortality. The SBP interval with the highest proportion of functional independence was chosen as reference. All analyses were performed for successful or unsuccessful recanalization (modified Treatment in Cerebral Ischemia score ≥2b or &lt;2b, respectively). The results were adjusted for known confounders in logistic regression models. Results-In the multivariable analyses, a higher SBP value as a continuous variable was associated unfavorably with all outcomes in patients with successful recanalization (n=2920) and with more SICH in patients with unsuccessful recanalization (n=711). SBP interval ≥160 mm Hg was associated with less functional independence (adjusted odds ratio, 0.28 [95% CIs, 0.15-0.53]) and more SICH (adjusted odds ratio, 6.82 [95% CIs, 1.53-38.09]) compared with reference 100 to 119 mm Hg in patients with successful recanalization. SBP ≥160 mm Hg was associated with more SICH (adjusted odds ratio, 6.62 [95% CIs, 1.07-51.05]) compared with reference 120 to 139 mm Hg in patients with unsuccessful recanalization. Conclusions-Higher SBP values were associated with less functional independence at 3 months in patients with successful recanalization and with more SICH regardless of recanalization status. © 2020 Lippincott Williams and Wilkins. All rights reserved

Outcome after intravenous thrombolysis in patients with acute lacunar stroke: An observational study based on SITS international registry and a meta-analysis

Background: Intravenous thrombolysis (IVT) for lacunar stroke (LS) is debated, as the underlying pathophysiological mechanism may not be thrombogenic. Aims: To investigate outcomes after IVT in LS in the SITS International Stroke Thrombolysis Register and perform a meta-analysis. Methods: LS was identified by both baseline NIHSS-subscores and discharge ICD-10 codes, and contrasted by IVT to non-IVT treated. IVT patients were predominantly from Europe, non-IVT patients predominantly from South America and Asia. Outcome measurements were functional independence (modified Rankin Scale [mRS] score ≤2), excellent outcome (mRS ≤ 1), and mortality at three months. Matched-control comparisons of symptomatic intracerebral hemorrhage (SICH) between IVT-treated LS and IVT-treated non-LS patients were performed. Additionally, we performed a meta-analysis. Results: Median age for IVT-treated LS patients (n = 4610) was 66 years vs. 64 years and NIHSS score was 6 vs. 3, compared to non-IVT-treated LS (n = 1221). Univariate outcomes did not differ; however, IVT-treated LS patients had higher adjusted odds ratios (aOR) for functional independence (aOR = 1.65, 95% CI = 1.28–2.13) but similar mortality at three months (aOR = 0.57, 0.29–1.13) than non-IVT-LS. Propensity-score matched analysis showed that IVT-treated LS patients had a 7.1% higher chance of functional independency than non-IVT LS patients (p &lt; 0.001). IVT-treated LS patients had lower odds for SICH (aOR = 0.33, 0.19–0.58 per SITS, aOR = 0.40, 0.27–0.57 per ECASS-2) than matched non-LS controls, which was mirrored in the meta-analysis. Conclusions: Our adjusted results show that IVT treatment in LS patients was associated with better functional outcome than non-IVT-treated LS and less SICH than IVT-treated non-LS patients