Intervention of Tyrosine Hydroxylase Expression Alters Joint Inflammation and Th17/Treg Imbalance in Collagen-Induced Arthritis

Neuroendocrine dysregulation has been associated with rheumatoid arthritis (RA). Tyrosine hydroxylase (TH), a rate-limiting enzyme for synthesis of neuroendocrine hormones such as epinephrine, is also expressed in T lymphocytes and regulates balance between helper T (Th) 17 cells and regulatory T (Treg) cells. Herein, we aimed to show that TH expression in joints alleviates joint inflammation and Th17/Treg imbalance in collagen-induced arthritis (CIA), an animal model of RA, and these effects may be implemented by the mechanism of epinephrine action on α1-adrenoreceptor (α1-AR) in T cells. METHODS: CIA was prepared by intradermal injection of collagen type II in tail base of DBA1/J mice. On the 33rd day post-immunization, lentiviral vectors encoding TH or TH shRNA were injected into ankle joints of CIA mice. Limb inflammation of the mice was assessed beginning from day 21 until day 69 post-immunization by measurement of limb swelling, erythema and rigidity. Th17 and Treg differentiation and function in ankle joints were assessed on day 69 post-immunization by test of the expression of Th17 transcriptional factor ROR-γt and the levels of proinflammatory cytokines interleukin (IL)-17 and IL-22 as well as the expression of Treg transcriptional factor Foxp3 and the levels of antiinflammatory cytokines transforming growth factor (TGF)-β1 and IL-10. T cells were obtained from the spleen of mice that had been immunized with collagen type II 41 day earlier and treated with epinephrine or α1-AR agonist phenylephrine in vitro. Flow cytometry was used to analyze the percentages of CD25-IL-17+ cells and CD25+Foxp3+ cells in CD4+ T cells. RESULTS: TH gene overexpression in ankle joints of CIA mice reduced limb inflammation and Th17-related transcription factor expression and inflammatory cytokine production but increased Treg-related antiinflammatory cytokine production in the joints. In contrast, TH gene silence in ankle joints of CIA mice enhanced limb inflammation and Th17 cell activity but decreased Treg cell function in the joints. Epinephrine upregulated α1-AR expression in T cells derived from CIA mice. Both epinephrine and phenylephrine reduced CIA-induced Th17 transcription factor expression and inflammatory cytokine production but enhanced Treg antiinflammatory cytokine production in vitro. CONCLUSION: Upregulating TH expression in joints alleviates joint inflammation and Th17/Treg imbalance in CIA at least partially by enhancing epinephrine action on α1-AR in T cells.

IL-10–producing B cells are enriched in murine pericardial adipose tissues and ameliorate the outcome of acute myocardial infarction

Acute myocardial infarction (MI) provokes an inflammatory response in the heart that removes damaged tissues to facilitate tissue repair/regeneration. However, overactive and prolonged inflammation compromises healing, which may be counteracted by antiinflammatory mechanisms. A key regulatory factor in an inflammatory response is the antiinflammatory cytokine IL-10, which can be produced by a number of immune cells, including subsets of B lymphocytes. Here, we investigated IL-10–producing B cells in pericardial adipose tissues (PATs) and their role in the healing process following acute MI in mice. We found that IL-10–producing B cells were enriched in PATs compared to other adipose depots throughout the body, with the majority of them bearing a surface phenotype consistent with CD5+ B-1a cells (CD5+ B cells). These cells were detected early in life, maintained a steady presence during adulthood, and resided in fat-associated lymphoid clusters. The cytokine IL-33 and the chemokine CXCL13 were preferentially expressed in PATs and contributed to the enrichment of IL-10–producing CD5+ B cells. Following acute MI, the pool of CD5+ B cells was expanded in PATs. These cells accumulated in the infarcted heart during the resolution of MI-induced inflammation. B cell-specific deletion of IL-10 worsened cardiac function, exacerbated myocardial injury, and delayed resolution of inflammation following acute MI. These results revealed enrichment of IL-10–producing B cells in PATs and a significant contribution of these cells to the antiinflammatory processes that terminate MI-induced inflammation. Together, these findings have identified IL-10–producing B cells as therapeutic targets to improve the outcome of MI.

IMMUNOREGULATORY PROFILE OF MICROSYMBIONTS OF THE INTESTINAL HUMAN BIOTOPE

Aim. To study in comparison immunoregulatory properties of dominant and associative microsymbionts metabolites in human large intestine’s eubiosis and dysbiosis. Materials and methods. 260 strains of bifidobacteria used as dominant microbiota, 132 cultures of conditionally pathogenic bacteria and fungi used as associative microsymbionts from 122 intestinal microsymbiocenoses. The cytokines production was studied in cultures of mononuclear cells co-cultivated with microsymbionts’ supernatants. The results were processed statistically (Statistica 10.0). Results. In eubiosis, dominant and associative microsymbionts showed immuno regulatory properties heterogeneity. In the case of phlogogenic cytokines, the associates equally exhibited stimulation / suppression / no effect on cytokines, except for enterococci and bacteroids, stimulating IL-8 secretion, and lactobacilli, inducing IFNy. Dominants were characterized by a unidirectional effect: IL-10 secretion stimulation and TNFa, IFNy and IL-17suppression, while retaining the induction of IL-10 in dysbiosis. In contrast, supernatants of the associates combined the opposing cytokines production: the early proinflammatory cytokine TNFa, the immunoregulatory cytokine IFNy and the antiinflammatory cytokine IL-10. Conclusion. Intestinal homeostasis in eubiosis is supported by differentiated effects of microsymbionts’ metabolites on the production of antiinflammatory, immunoregulatory cytokines with the formation of an optimal balance, limiting inflammatory and autoimmune reactions. The dominance of the immunoregulatory properties remains intact in the conditions of dysbiosis, and the variety of effects on pro-/antiin-flammatory cytokines is limited in the associates.

Deficiency of a sulfotransferase for sialic acid-modified glycans mitigates Alzheimer’s pathology

We previously showed that microglial keratan sulfate (KS) was induced in amyotrophic lateral sclerosis. However, the functional roles of the glycan and its synthetic enzyme in neurodegenerative diseases, such as Alzheimer’s disease (AD), a progressive disorder, are unclear. In our study, KS modified with sialic acids having a molecular mass of 125–220 kDa and the carbohydrate sulfotransferase GlcNAc6ST1 were up-regulated in the brains of two transgenic mouse models (J20 and Tg2576) and the brains of patients with AD. GlcNAc6ST1-deficient J20 (J20/GlcNAc6ST1−/−) mice demonstrated a complete absence of the microglial sialylated KS. J20/GlcNAc6ST1−/− primary microglia showed an increased level of amyloid-β phagocytosis and were hyperresponsive to interleukin 4, a potent antiinflammatory cytokine. Moreover, J20/GlcNAc6ST1−/− mice manifested reduced cerebral amyloid-β deposition. GlcNAc6ST1-synthesizing sialylated KS thus modulates AD pathology. Inhibition of KS synthesis by targeting GlcNAc6ST1 may therefore be beneficial for controlling AD pathogenesis.

INFLUENCE OF EPOETIN ALFA ON LEVEL OF PROINFLAMMATORYAND ANTIINFLAMMATORY CYTOKINE OF PATIENTS IN MAINTENCE HEMODIALYSIS

Summary. The aim of the present research was to study the influence of еpoetin alfa to the level of pro- and anti-inflammatory cytokines in patients with anemia treated by hemodialysis (HD). Materials and methods: We examined 73patients with anemia treated by hemodialysis (mean age 45,85 ±1,21 years). Patients were divided into 2groups: I group - comparison (n = 32), II group - treatment by epoetin alfa (n = 41). The levels of hemoglobin, C-reactiveprotein, ferritin, albumin, pro-and anti-inflammatory cytokines were determined before and after treatment in patients of both groups. The duration of treatment was 5 months. Results: Epoetin alfa increases Hb levels in patients treated by HD. After epoetin alfa applying reduction of proinflammatory cytokines ( TNF -a, IL -ip, IL -17, IL -18) and increased levels of IL -10 were observed. Conclusions: The clinical efficacy of the epoetin alfa treatment at the moment of completion of treatment was 75.6% (level of Hb > 110 g/L ). Epoetin alfa, improving the level of Hb, reduces the activity of chronic inflammation.