The Correlation of CD206, CD209, and Disease Severity in Behçet's Disease with Arthritis

Characterization of Hofbauer cell polarization and VEGF localization in human term placenta from active and inactive pregnant individuals

Physical activity (PA) during pregnancy is associated with parental and fetal health benefits; however, the mechanisms through which these benefits arise are yet to be fully understood. In healthy pregnancies Hofbauer cells (HBCs) comprise a heterogenous population containing CD206+ and CD206- phenotypes. In healthy pregnancies, CD206+ represent the majority, while dysregulations have been associated with pathological conditions. HBCs have also been identified as potential drivers of angiogenesis. As PA induces changes in macrophage polarization in non-pregnant populations, this novel study examined the relationship between PA and HBC polarization and to identify which HBC phenotypes express VEGF. Participants were classified as active or inactive, and immunofluorescence cell-labelling was used to quantify total HBCs, CD206+ HBCs, and the proportion of total HBCs expressing CD206. Immunofluorescent colocalization assessed which phenotypes expressed VEGF. Protein and mRNA expression of CD68 and CD206 were measured in term placenta tissue using Western blot and RT-qPCR, respectively. Both CD206+ and CD206- HBCs expressed VEGF. The proportion of CD206+ HBCs was elevated in active individuals; however, CD206 protein expression was observed to be lower in active participants. Combined with a lack of significant differences in CD206 mRNA levels, these findings suggest potential PA-mediated responses in HBC polarization and CD206 translational regulation.

Neutrophil, NETs and Behçet's disease: A review

Behçet's disease (BD) is a chronic systemic vasculitis characterized by recurrent oral and genital ulcers, skin lesions, articular, neurological, vascular and sight-threatening ocular inflammation. BD is thought to share both autoimmune and autoinflammatory disease features. BD is triggered by environmental factors such as infectious agents in genetically predisposed subjects. Neutrophils seem to play an instrumental role in BD and recent works regarding the role of neutrophils extracellular traps (NETs) provides new insight in the pathophysiology of BD and the mechanisms involved in immune thrombosis. This review provides a recent overview on the role of neutrophils and NETs in the pathogenesis of BD.

The role of bacteria and viruses in Behçet syndrome: Should we move towards new paradigms?

The etiological complexity of Behçet syndrome (BS), an immune-mediated rare form of vasculitis characterized by multi-organ involvement, is still elusive due to an incomplete understanding of the synergy between genetic susceptibility, environmental triggers, and an abnormal immune response. Long-standing theories regarding the origins of BS include the involvement of infectious organisms supporting an aberrant immunological response through different mechanisms, including molecular mimicry. Additionally, it has been demonstrated that the BS phenotypes are linked to oral and gut microbiome dysbiosis, which is a dynamic reservoir of millions of microbes containing proteins and metabolites that can mimic the autoantigens. Infections, including viral pathogens, could potentially trigger the inflammation and symptoms of BS. In this review, we aim to describe the available evidence on the cross-talk between BS and infections in order to discuss potential clinical implications and possible therapeutic targets.

Differences in Expression of Human Leukocyte Antigen Class II Subtypes and T Cell Subsets in Behçet's Disease with Arthritis

It has been reported Human Leukocyte Antigen (HLA) gene polymorphism is a risk factor for the development of Behçet’s disease (BD). In this study, the association of HLA class II subtypes HLA-DP, DQ, DR, and T cell subsets in BD patients with arthritis was evaluated. Frequencies of HLA-DP, DQ, DR positive cells, and T cell subsets in peripheral blood leukocytes (PBL) were measured by flow cytometric analysis in BD, and compared to rheumatoid arthritis as disease controls and healthy controls. Frequencies of HLA-DQ were significantly decreased in whole PBL and granulocytes of BD active patients as compared to healthy controls. In monocytes populations, proportions of HLA-DR positive cells were significantly increased in BD active patients as compared to healthy controls. Proportions of CD4+CCR7+ and CD8+CCR7+ cells were significantly higher in BD active patients than in BD inactive in whole PBL. Frequencies of CD4+CD62L- and CD8+CD62L- cells in lymphocytes were significantly decreased in active BD than those in inactive BD. There were also correlations between disease activity markers and T cell subsets. Our results revealed HLA-DP, DQ, and DR expressing cell frequencies and several T cell subsets were significantly correlated with BD arthritis symptoms.

Behçet's disease: An immunogenetic perspective

Behçet's disease (BD) is a chronic and rare multisystemic disorder defined by autoimmunity and inflammatory characteristics, manifested by ocular lesions, recurrent genital and oral ulcers, skin symptoms and arthritis as well as neurological, intestinal, and vascular involvement. Despite the unknown cause of BD, there is some strong documentation for immunological, genetic, environmental, and infectious factors playing a role in the pathogenesis of BD. While the nature of the genetic variants remains unidentified, many genetic risk factors are considered to contribute to BD susceptibility. Along with human leukocyte antigen gene encoding B*51 (HLA-B*51) and areas including the major histocompatibility complex class I, genome-wide association studies have recognized numerous other BD susceptibility genes including those encoding interleukin (IL)-10, IL-12 receptor β 2 (IL-12RB2), IL-23 receptor (IL-23R), C-C chemokine receptor 1 gene, signal transducer and activator of transcription 4 (STAT4), endoplasmic reticulum aminopeptidase (ERAP1), and genes encoding killer cell lectin-like receptor family members (KLRC4-KLRK1). It is believed that BD could be considered as a disorder lying in between autoimmune and autoinflammatory syndromes. The positive responses to classical immunosuppressive agents like azathioprine and cyclosporine and involvement of autoantigens in the initiation of the disorder are the main BD features that reflect the autoimmune nature of the disorder. In this review, we address recent findings on the role of common cytokines, antibodies and immunogenetic factors in BD.

HSV-Induced Systemic Inflammation as an Animal Model for Behçet's Disease and Therapeutic Applications

Behçet’s disease (BD) affects multiple organs. It is mainly characterized by recurrent oral, skin, and genital aphthous ulcers, and eye involvement. Successful management of BD is increasing, although its etiology remains unclear. A number of etiologies have been proposed, including environmental, genetic, viral, and immunological factors. To understand its complex etiology and improve its management, animal models of BD have been used to enable more effective therapeutic applications with increased clinical significance. An herpes simplex virus (HSV) type 1-induced BD mouse model has shown disease characteristics similar to those seen in BD patients. An HSV-induced BD animal model has been used to test various therapeutic modalities. The applied modalities are several materials that are derived from natural products, conventional therapeutics, and possible biologics. In this review, we provided how they regulate inflammation in an HSV-induced BD model.

Hypertension and increased endothelial mechanical stretch promote monocyte differentiation and activation: roles of STAT3, interleukin 6 and hydrogen peroxide

Aims

Monocytes play an important role in hypertension. Circulating monocytes in humans exist as classical, intermediate, and non-classical forms. Monocyte differentiation can be influenced by the endothelium, which in turn is activated in hypertension by mechanical stretch. We sought to examine the role of increased endothelial stretch and hypertension on monocyte phenotype and function.

Methods and results

Human monocytes were cultured with confluent human aortic endothelial cells undergoing either 5% or 10% cyclical stretch. We also characterized circulating monocytes in normotensive and hypertensive humans. In addition, we quantified accumulation of activated monocytes and monocyte-derived cells in aortas and kidneys of mice with Angiotensin II-induced hypertension. Increased endothelial stretch enhanced monocyte conversion to CD14++CD16+ intermediate monocytes and monocytes bearing the CD209 marker and markedly stimulated monocyte mRNA expression of interleukin (IL)-6, IL-1β, IL-23, chemokine (C-C motif) ligand 4, and tumour necrosis factor α. STAT3 in monocytes was activated by increased endothelial stretch. Inhibition of STAT3, neutralization of IL-6 and scavenging of hydrogen peroxide prevented formation of intermediate monocytes in response to increased endothelial stretch. We also found evidence that nitric oxide (NO) inhibits formation of intermediate monocytes and STAT3 activation. In vivo studies demonstrated that humans with hypertension have increased intermediate and non-classical monocytes and that intermediate monocytes demonstrate evidence of STAT3 activation. Mice with experimental hypertension exhibit increased aortic and renal infiltration of monocytes, dendritic cells, and macrophages with activated STAT3.

Conclusions

These findings provide insight into how monocytes are activated by the vascular endothelium during hypertension. This is likely in part due to a loss of NO signalling and increased release of IL-6 and hydrogen peroxide by the dysfunctional endothelium and a parallel increase in STAT activation in adjacent monocytes. Interventions to enhance bioavailable NO, reduce IL-6 or hydrogen peroxide production or to inhibit STAT3 may have anti-inflammatory roles in hypertension and related conditions.