Hidenori Ohnishi

Bio: Hidenori Ohnishi is an academic researcher from Gifu University. The author has contributed to research in topics: Medicine & Immunodeficiency. The author has an hindex of 21, co-authored 114 publications receiving 1540 citations.

Structural basis for the multiple interactions of the MyD88 TIR domain in TLR4 signaling

Abstract: Myeloid differentiating factor 88 (MyD88) and MyD88 adaptor-like (Mal) are adaptor molecules critically involved in the Toll-like receptor (TLR) 4 signaling pathway. While Mal has been proposed to serve as a membrane-sorting adaptor, MyD88 mediates signal transduction from activated TLR4 to downstream components. The Toll/Interleukin-1 receptor (TIR) domain of MyD88 is responsible for sorting and signaling via direct or indirect TIR−TIR interactions between Mal and TLR4. However, the molecular mechanisms involved in multiple interactions of the TIR domain remain unclear. The present study describes the solution structure of the MyD88 TIR domain. Reporter gene assays revealed that 3 discrete surface sites in the TIR domain of MyD88 are important for TLR4 signaling. Two of these sites were shown to mediate direct binding to the TIR domain of Mal. Interestingly, Mal-TIR, but not MyD88-TIR, directly binds to the cytosolic TIR domain of TLR4. These observations suggested that the heteromeric assembly of TIR domains of the receptor and adaptors constitutes the initial step of TLR4 intracellular signal transduction.

The structure and binding mode of interleukin-18

Abstract: Interleukin-18 (IL-18), a cytokine formerly known as interferon-gamma- (IFN-gamma-) inducing factor, has pleiotropic immunoregulatory functions, including augmentation of IFN-gamma production, Fas-mediated cytotoxicity and developmental regulation of T-lymphocyte helper type I. We determined the solution structure of IL-18 as a first step toward understanding its receptor activation mechanism. It folds into a beta-trefoil structure that resembles that of IL-1. Extensive mutagenesis revealed the presence of three sites that are important for receptor activation: two serve as binding sites for IL-18 receptor alpha (IL-18Ralpha), located at positions similar to those of IL-1 for IL-1 receptor type I (IL-1RI), whereas the third site may be involved in IL-18 receptor beta (IL-18Rbeta) binding. The structure and mutagenesis data provide a basis for understanding the IL-18-induced heterodimerization of receptor subunits, which is necessary for receptor activation.

The structural basis for receptor recognition of human interleukin-18

Abstract: Interleukin (IL)-18 is a proinflammatory cytokine that belongs to the IL-1 family and plays an important role in inflammation. The uncontrolled release of this cytokine is associated with severe chronic inflammatory disease. IL-18 forms a signalling complex with the IL-18 receptor α (Rα) and β (Rβ) chains at the plasma membrane, which induces multiple inflammatory cytokines. Here, we present a crystal structure of human IL-18 bound to the two receptor extracellular domains. Generally, the receptors' recognition mode for IL-18 is similar to IL-1β; however, certain notable differences were observed. The architecture of the IL-18 receptor second domain (D2) is unique among the other IL-1R family members, which presumably distinguishes them from the IL-1 receptors that exhibit a more promiscuous ligand recognition mode. The structures and associated biochemical and cellular data should aid in developing novel drugs to neutralize IL-18 activity.

Propranolol as an alternative treatment option for pediatric lymphatic malformation.

Abstract: Lymphatic malformation (LM), which was previously termed lymphangioma, is a rare congenital malformation of the lymphatic system and its treatment is still challenging. Propranolol (beta blocker) has been recently developed as a first-line treatment of infantile hemangioma. Our study aimed to assess the effect of propranolol on pediatric LM and the relationship between its effectiveness and vascular endothelial growth factor (VEGF) family members (VEGF-A, C and D). Six Japanese patients with LM (age range: 10 months-19 years old; 2 macrocystic, 2 microcystic and 2 combined type) were enrolled. Oral propranolol was administered at 2 mg/kg/day. The efficacy of propranolol for LM was evaluated by the rate of volume change as calculated from MRI imaging and by symptomatic improvement. In all patients, there were no significant side effects. Patients 3 and 5 were classified as objective responders with tumor volume reduction of 30.6% and 22.9%, respectively, at 24 weeks. Patient 1 showed 8% tumor volume reduction and patient 6 showed symptomatic improvement, hence, both were classified as minimal responders. The other two patients were classified as non-responders. Plasma VEGF-A, C, and D levels were significantly higher in the LM group than in the controls (all P < 0.01 by Mann-Whitney test). VEGF-A and D levels at 24 weeks were significantly lower than those at pre-treatment (P = 0.031, 0.047 by Wilcoxon matched pairs test). Though further trials with this treatment must be carried out, we propose that propranolol may be an alternative therapy option for intractable LM.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice—Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Sixth Special Issue

Abstract: The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating, and categorizing indications for the evidence-based use of therapeutic apheresis in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the Committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Seventh Edition of the JCA Special Issue continues to maintain this methodology and rigor to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Seventh Edition, like its predecessor, has consistently applied the category and grading system definitions in the fact sheets. The general layout and concept of a fact sheet that was used since the fourth edition has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis in a specific disease entity. The Seventh Edition discusses 87 fact sheets (14 new fact sheets since the Sixth Edition) for therapeutic apheresis diseases and medical conditions, with 179 indications, which are separately graded and categorized within the listed fact sheets. Several diseases that are Category IV which have been described in detail in previous editions and do not have significant new evidence since the last publication are summarized in a separate table. The Seventh Edition of the JCA Special Issue serves as a key resource that guides the utilization of therapeutic apheresis in the treatment of human disease. J. Clin. Apheresis 31:149-162, 2016. © 2016 Wiley Periodicals, Inc.

Association of the adam33 gene with asthma and bronchial hyperresponsiveness

Abstract: Van Eerdewegh P, Little RD, Dupuis J, et al Nature 2002;418:426–430 To identify novel genetic polymorphisms associated with bronchial hyperresponsiveness (BHR) in asthma Four hundred sixty white affected sib-pair families from the United States and the United Kingdom with current asthma A genetic linkage analysis was performed for current asthma and BHR Case-control, transmission disequilibrium, and haplotype analyses were conducted to identify the gene(s) most commonly associated with asthma Novel genes of interest were …