Nogo receptor-Fc delivered by haematopoietic cells enhances neurorepair in a multiple sclerosis model.

Nogo receptor 1 is the high affinity receptor for the potent myelin-associated inhibitory factors that make up part of the inflammatory extracellular milieu during experimental autoimmune encephalomyelitis. Signalling through the Nogo receptor 1 complex has been shown to be associated with axonal degeneration in an animal model of multiple sclerosis, and neuronal deletion of this receptor homologue, in a disease specific manner, is associated with preserving axons even in the context of neuroinflammation. The local delivery of Nogo receptor(1-310)-Fc, a therapeutic fusion protein, has been successfully applied as a treatment in animal models of spinal cord injury and glaucoma. As multiple sclerosis and experimental autoimmune encephalomyelitis exhibit large numbers of inflammatory cell infiltrates within the CNS lesions, we utilized transplantable haematopoietic stem cells as a cellular delivery method of the Nogo receptor(1-310)-Fc fusion protein. We identified CNS-infiltrating macrophages as the predominant immune-positive cell type that overexpressed myc-tagged Nogo receptor(1-310)-Fc fusion protein at the peak stage of experimental autoimmune encephalomyelitis. These differentiated phagocytes were predominant during the extensive demyelination and axonal damage, which are associated with the engulfment of the protein complex of Nogo receptor(1-310)-Fc binding to myelin ligands. Importantly, mice transplanted with haematopoietic stem cells transduced with the lentiviral vector carrying Nogo receptor(1-310)-Fc and recovered from the peak of neurological decline during experimental autoimmune encephalomyelitis, exhibiting axonal regeneration and eventual remyelination in the white matter tracts. There were no immunomodulatory effects of the transplanted, genetically modified haematopoietic stem cells on immune cell lineages of recipient female mice induced with experimental autoimmune encephalomyelitis. We propose that cellular delivery of Nogo receptor(1-310)-Fc fusion protein through genetically modified haematopoietic stem cells can modulate multifocal experimental autoimmune encephalomyelitis lesions and potentiate neurological recovery.

Antagonizing FcαR1 (CD89) as treatment in IgA-mediated chronic inflammation and autoimmunity.

Introduction: Immunoglobulin A (IgA) is mostly considered as a non-inflammatory regulator at mucosal areas. However, previous work of our group showed that IgA can also be involved in disease pathology, because it provides a potent stimulus to activate neutrophils after crosslinking of surface CD89 (FcaRI), resulting in chronic inflammation and tissue damage. IgA (auto)antibodies and neutrophils are key players in various diseases, including blistering skin diseases and rheumatoid arthritis. Therefore, we generated an array of anti-CD89 monoclonal antibodies (mAbs) for therapeutic targeting of CD89. The biological activity of newly developed anti-human CD89 mAbs and their potential therapeutic capacity were investigated. Methods: Human neutrophils were isolated from heparinized healthy donor blood. The ability of anti-CD89 mAbs to bind human neutrophils was investigated by flow cytometry. Furthermore, the capacity of these anti-CD89 mAbs to inhibit IgA-mediated phagocytosis, neutrophil extracellular trap (NET) release and migration was studied. To this end, neutrophils were pre-incubated with/without anti-CD89 mAbs after which they were stimulated with IgA-coated beads. The amount of phagocytosed beads, NET release and migrated neutrophils were subsequently analysed. In parallel, chemoattractant leukotriene B4 and lactoferrin (as a measure for degranulation) release were determined. Finally, the therapeutic potential of our prototypic anti-CD89 mAb clone 10E7 was in vivo tested in anti-mouse collagen XVII human IgA-treated transgenic CD89 mice, a preclinical model for autoimmune linear IgA bullous disease (LABD). Results: Our results show that all generated anti-CD89 mAbs bound surface CD89 on neutrophils. Although these anti-CD89 mAbs bind to different epitopes on EC1 of CD89, they all have the capacity to inhibit IgA-mediated phagocytosis, neutrophil extracellular trap (NET) release and neutrophil migration. Moreover, IgA mediated leukotriene B4 and lactoferrin release are decreased in supernatant from anti-CD89 mAbs-treated neutrophils. Finally, anti-CD89 mAb clone 10E7, that was selected based on its selective binding profile on tissue micro arrays, reduced anti-mouse collagen XVII hIgA-induced neutrophil influx in an in vivo linear IgA bullous disease (LABD) mice model. Conclusion: This study clearly indicates that our newly developed anti-CD89 mAbs inhibited IgA-induced neutrophil activation and reduced anti-autoantigen IgA-induced neutrophil influx in vivo, supporting further clinical development for the treatment of LABD.

Role of the nuclear receptor subfamily 4a in mast cells in the development of irritable bowel syndrome.

The activation of mast cells (MCs) and mediator release are closely related to the pathophysiology of irritable bowel syndrome (IBS). However, the exact underlying mechanisms are still not completely understood. The nuclear receptor subfamily 4a (Nr4a) is a family of orphan nuclear receptors implicated in regulating MC activation, degranulation, cytokine/chemokine synthesis and release. Acute and chronic stress trigger hypothalamic-pituitaryadrenal axis (HPA) activation to induce the release of corticotropin-releasing hormone (CRH), resulting in MC activation and induction of the Nr4a family. Our newest data showed that Nr4a members were specially over-expressed in colonic MCs of the chronic water-avoidance stress (WAS)-induced visceral hyperalgesia mice, suggesting that Nr4a members might be involved in the pathophysiology of visceral hypersensitivity. In this review, we highlight the present knowledge on roles of Nr4a members in the activation of MCs and the pathophysiology of IBS, and discuss signaling pathways that modulate the activation of Nr4a family members. We propose that a better understanding of Nr4a members and their modulators may facilitate the development of more selective and effective therapies to treat IBS patients.

Soluble Nogo receptor 1 fusion protein protects neural progenitor cells in rats with ischemic stroke.

Soluble Nogo66 receptor-Fc protein (sNgR-Fc) enhances axonal regeneration following central nervous system injury. However, the underlying mechanisms remain unclear. In this study, we investigated the effects of sNgR-Fc on the proliferation and differentiation of neural progenitor cells. The photothrombotic cortical injury model of ischemic stroke was produced in the parietal cortex of Sprague-Dawley rats. The rats with photothrombotic cortical injury were randomized to receive infusion of 400 µg/kg sNgR-Fc (sNgR-Fc group) or an equal volume of phosphate-buffered saline (photothrombotic cortical injury group) into the lateral ventricle for 3 days. The effects of sNgR-Fc on the proliferation and differentiation of endogenous neural progenitor cells were examined using BrdU staining. Neurological function was evaluated with the Morris water maze test. To further examine the effects of sNgR-Fc treatment on neural progenitor cells, photothrombotic cortical injury was produced in another group of rats that received transplantation of neural progenitor cells from the hippocampus of embryonic Sprague-Dawley rats. The animals were then given an infusion of phosphate-buffered saline (neural progenitor cells group) or sNgR-Fc (sNgR-Fc + neural progenitor cells group) into the lateral ventricle for 3 days. sNgR-Fc enhanced the proliferation of cultured neural progenitor cells in vitro as well as that of endogenous neural progenitor cells in vivo, compared with phosphate-buffered saline, and it also induced the differentiation of neural progenitor cells into neurons. Compared with the photothrombotic cortical injury group, escape latency in the Morris water maze and neurological severity score were greatly reduced, and distance traveled in the target quadrant was considerably increased in the sNgR-Fc group, indicating a substantial improvement in neurological function. Furthermore, compared with phosphate-buffered saline infusion, sNgR-Fc infusion strikingly improved the survival and differentiation of grafted neural progenitor cells. Our findings show that sNgR-Fc regulates neural progenitor cell proliferation, migration and differentiation. Therefore, sNgR-Fc is a potential novel therapy for stroke and neurodegenerative diseases, The protocols were approved by the Committee on the Use of Live Animals in Teaching and Research of the University of Hong Kong (approval No. 4560-17) in November, 2015.

The Emerging Picture of Mast Cell Activation: The Complex Regulatory Network of High-Affinity Receptor for Immunoglobulin E Signaling.

It is now well known that immunoglobulin E (IgE) and mast cells (MCs) are important participants in allergic diseases. MCs contain electron-dense secretory granules which are filled with inflammatory mediators. The interaction of an allergen (antigen) with an antigen-specific IgE-bound high-affinity receptor for IgE (FcεRI) is an essential step in MC activation as well as subsequent downstream signaling events. What we know is that IgE and FcεRI activate a complex regulatory network (i.e., signaling molecules and messengers) that governs both the type of MC activation and the symptoms of allergic disease. This review focuses on recent discoveries that shed new light on FcεRI signaling networks, holding promise for the development of new therapeutic solutions in the treatment of allergic diseases.

Fc gamma receptor IIIa polymorphism is not associated with susceptibility to systemic lupus erythematosus in Brazilian patients.

We evaluated the possible association between FCGR3A V/F (158) polymorphism and SLE susceptibility and clinical phenotype in 305 sequentially retrieved SLE patients and 300 healthy controls from the southeastern part of Brazil by allele-specific polymerase chain reaction. Our results showed no association between FCGR3A 158V/F alleles and susceptibility to SLE in this series of patients albeit the heterozygous genotype was strongly associated with the disease.

Fc gamma receptor IIIa polymorphism is not associated with susceptibility to systemic lupus erythematosus in Brazilian patients / Polimorfismo do receptor Fc gama IIIa não está associado à susceptibilidade ao lúpus eritematoso sistêmico em pacientes brasileiros

ABSTRACT We evaluated the possible association between FCGR3A V/F (158) polymorphism and SLE susceptibility and clinical phenotype in 305 sequentially retrieved SLE patients and 300 healthy controls from the southeastern part of Brazil by allele-specific polymerase chain reaction. Our results showed no association between FCGR3A 158V/F alleles and susceptibility to SLE in this series of patients albeit the heterozygous genotype was strongly associated with the disease.

RESUMO Avaliou-se a possível associação entre o polimorfismo FCGR3A V/F (158) e a suscetibilidade e o fenótipo clínico do lúpus eritematoso sistêmico (LES) em 305 pacientes com LES admitidos sequencialmente e 300 controles saudáveis da Região Sudeste do Brasil por reação em cadeia da polimerase alelo-específica. Os resultados do presente estudo mostraram não haver associação entre os alelos FCGR3A 158 V/F e a suscetibilidade ao LES nessa série de pacientes, ainda que o genótipo heterozigoto tenha sido fortemente associado à doença.

rhTNFR: Fc Suppresses the Development of Endometriosis in a Mouse Model by Downregulating Cell Proliferation and Invasiveness.

Tumor necrosis factor α (TNF-α), a proinflammatory cytokine, may play an important role in the pathogenesis of endometriosis; therefore, TNF-α inhibitors potentially have an effect on endometriosis. To investigate the effect of anti-TNF-α treatment on endometriosis, 2 TNF-α inhibitors: recombinant human TNF receptor: Fc fusion protein (rhTNFR: Fc) and TNF-α monoclonal antibody (TNF-α mAb) were used to treat human eutopic endometrial stromal cells (hESCs), and the effects on cell survival, cell cycle, and invasiveness were compared. It was found that rhTNFR: Fc suppressed the TNF-α-induced hESC survival and invasiveness but not TNF-α mAb. Recombinant human TNF receptor: Fc fusion protein decreased the S phase of hESC compared with the TNF-α-treated group. Then, we used a surgically induced mouse model of endometriosis to study the effect of rhTNFR: Fc treatment in vivo. The fluorescence intensity and the size of implanted endometriotic lesions in the mouse model were decreased by rhTNFR: Fc. In conclusion, rhTNFR: Fc suppresses hESC survival and invasiveness and decreases the fluorescence intensity and implant size in the mouse model of endometriosis.

Effects of tumor necrosis factor-α on ventricular arrhythmias in rats with acute myocardial infarction / 中华急诊医学杂志

Objective To explore the effects of tumor necrosis factor-α (TNF-α) on ventricular arrhythmias resulted from acute myocardial infarction (AMI) in rats. Method Two hundred and forty male Wistar rats were randomized (random number) into sham operation group, AMI group and recombinant human tumor necrosis factor receptor (rhTNFR) fusion protein (Fc) group. Acute anterior wall myocardial infarction was produced in rats of AMI group with ligating the left anterior descending coronary artery (LAD) , and the rats were just operated without ligation of LAD in sham group. The rats of Fc group were treated with rhTNFR-Fc (10 mg/kg), a TNF-α antagonist, 24 hours before LAD ligation. The original ECG was recorded 10 min before ligation and the ECGs of ventricular arrhythmias occurred spontaneously or induced by programmed electrical stimulation were recorded 10 min, 20 min, 30 min, 60 min, 3 h, 6 h and 12 hours after ligation. The protein levels and mRNA expressions of TNF-α in rats in different groups were detected with histochemistry and real-time fluorescent quantitative PCR. Results The expressions of TNF-α mRNA and levels of TNF-α protein markedly increased 10 min after infarction, reached the climax 20-30 min later, and then gradually returned to the original level in AMI group and Fc group. The time-windows of spontaneous and induced ventricular arrhythmias were consistent with the time-window of expressions of TNF-α mRNA and levels of TNF-α protein. Compared with AMI group, there were lower levels of TNF-α protein and lower incidence of ventricular arrhythmias in Fc group ( P < 0.05) , but there was no significant difference in TNF-α mRNA between two groups. There was no obvious change in TNF-α in rats of sham operation group. Conclusions The expressions of TNF-α mRNA and levels of TNF-α protein induced by AMI could contribute the initiation of ventricular arrhythmias.

Targeting therapy of SLE associated thrombocytopenia with labeled antibody in vitro / 吉林大学学报(医学版)

Objective To discuss the feasibility and effect of labeled antibody on targeting therapy of systemic lupus erythematosus(SLE) associated thrombocytopenia.Methods MTX-IVIG conjugate was prepared by indirect and direct cross linking,and the binding ability of it to Fc fragment was detected by indirect immunofluor-escence.The killing activity of the conjugate was detected by MTT method using murine macrophage with Fc receptor and strain U937 of human monocytic leukemia cell as targets.Results Conjugation showed stronger cytotoxicity upon target cells than free MTX,and it showed less cytotoxic effect on Fc receptor negative cells compared with the positive ones.IVIG-HSA-MTX restrained the phagocyte of macrophage.The killing effect of IVIG-HSA-MTX was significantly stronger than that of IVIG-MTX.Conclusion The conjugation can show a highly specific cytotoxicity upon mononuclear-macrophage in vitro.

Fcalpha Receptor Gene Polymorphism and mRNA Expression in Children with IgA Nephropathy or Henoch-Scholein Nephritis / 대한신장학회잡지

BACKGROUND: The correlations among polymorphisms of the Fc alpha receptor gene (Fc alpha R), its mRNA expressions, and clinical features of IgA nephropathy (IgAN) and Henoch-Scholein nephritis (HSN) in children were analyzed. METHODS: In children with IgAN (n=26) and HSN (n=30), genotypes for -114 T/C and +6 T/C polymorphisms in the promoter region of Fc alpha R gene were determined by PCR-RFLP. And Fc alpha R mRNA expressions from the peripheral mononuclear cells (n=41) were semi-quantitatively measured by competitive RT-PCR. The clinico-pathological findings were reviewed retrospectively. RESULTS: The distributions of -114 T/C and +56 T/C genotypes were not different between total patients and controls. However, the frequency of -114 CC genotype was significantly higher in the HSN patients than in control (13.3% vs 2.0%, OR=7.54, p<0.05). The genotypes for the two polymorphisms did not correlate with either clinical presentations or disease courses. The Fc alpha R mRNA expression showed no difference between patients and controls, and did not correlate with serum IgA level, either. CONCLUSION: The -114 T/C polymorphism of the Fc alpha R gene contributes as a risk factor for the development of HSN in children. However, the genotypic differences do not affect Fc alpha R mRNA transcription and not correlate with clinical features and disease courses.

Protective effect of soluble tumor necrosis factor receptor-Fc fusion protein on multiple organ dysfunction syndrome in rats / 第二军医大学学报

Objective: To investigate the relations among the levels of TNF,TNFR and the frequency of multiple organ dysfunction syndrome(MODS),and to study the possible effect of sTNFR Fc in the treatment of MODS. Methods: Totally 48 healthy male SD rats were randomly divided into the control group, the MODS model group and the sTNFR Fc group.MODS group were established by two hit. At the early stage of resuscitation, 0.4 mg/kg of sTNFRp75 Fc was administrated via vein as the sTNFR Fc group. Levels of TNFR1 and TNFR2 expression on the cell membrane of various organs in the 3 groups were analyzed by Western blot. Results: After administration of sTNFRp75 Fc, the functions of the main organs were obviously improved. The morbidity(43.7%) of MODS and the mortality(12.5%) of animals decreased significantly in the sTNFR Fc group compared with model group(100.0% and 50.0%). The serum TNF bioactivity was significantly blocked by TNFR Fc administration. Both TNFR1 and TNFR2 expression in the control group were low while higher in the MODS model group; however, they were decreased significantly in various organs after sTNFRp75 Fc treatment.Conclusion: Our results suggest that TNF ? and TNFR play key roles in the pathogenesis of MODS and sTNFR could reverse the effects of TNF ? and decrease the morbidity of MODS and the mortality of animals in MODS model.