花粉曝露室のスギ花粉曝露によりスギ花粉症患者に誘発された鼻粘膜ヒスタミンH1受容体mRNA発現亢進に対する抗ヒスタミン薬の影響

In the present study, we examined the effects of antihistamine on the up-regulation of H1R mRNA in the nasal mucosa of patients with pollinosis induced by controlled exposure to pollen using an environmental exposure unit. Out of 20 patients, we designated 14 responders, whose levels of H1R mRNA in the nasal mucosa were increased after the first pollen exposure and excluded 6 non-responders. Accordingly, the first exposure to pollen without treatment significantly induced both nasal symptoms and the upregulation of H1R mRNA in the nasal mucosa of the responders. Subsequently, prophylactic administration of antihistamine prior to the second pollen exposure significantly inhibited both of the above effects in the responders. Moreover, the nasal expression of H1R mRNA before the second pollen exposure in the responders pretreated with antihistamine was significantly decreased, as compared with that before the first pollen exposure without treatment. These findings suggest that antihistamines suppressed histamine-induced transcriptional activation of H1R gene in the nasal mucosa, in addition to their blocking effect against histamine on H1R, resulting in a decrease of nasal symptoms. These findings further suggest that by their inverse agonistic activity, antihistamines suppress the basal transcription of nasal H1R in the absence of histamine in responders

Trk-fused gene (TFG) regulates pancreatic beta cell mass and insulin secretory activity

The Trk-fused gene (TFG) is reportedly involved in the process of COPII-mediated vesicle transport and missense mutations in TFG cause several neurodegenerative diseases including hereditary motor and sensory neuropathy with proximal dominant involvement (HMSN-P). The high coincidence ratio between HMSN-P and diabetes mellitus suggests TFG to have an important role(s) in glucose homeostasis. To examine this possibility, β-cell specific TFG knockout mice (βTFG KO) were generated. Interestingly, βTFG KO displayed marked glucose intolerance with reduced insulin secretion. Immunohistochemical analysis revealed smaller β-cell masses in βTFG KO than in controls, likely attributable to diminished β-cell proliferation. Consistently, β-cell expansion in response to a high-fat, high-sucrose (HFHS) diet was significantly impaired in βTFG KO. Furthermore, glucose-induced insulin secretion was also markedly impaired in islets isolated from βTFG KO. Electron microscopic observation revealed endoplasmic reticulum (ER) dilatation, suggestive of ER stress, and smaller insulin crystal diameters in β-cells of βTFG KO. Microarray gene expression analysis indicated downregulation of NF-E2 related factor 2 (Nrf2) and its downstream genes in TFG depleted islets. Collectively, TFG in pancreatic β-cells plays a vital role in maintaining both the mass and function of β-cells, and its dysfunction increases the tendency to develop glucose intolerance.This study was partly supported by a Grant-in-Aid for Research Activity Start-up (JSPS KAKENHI Grant Number JP15H06427) (to T.Y.) from the Ministry of Education, Science, Sports and Culture, Japan, and grants from Mitsubishi Tanabe Pharma (to T.Y.), Novartis Pharma (to T.Y.), Takeda Science Foundation (to Y.N.), Asahi Life Foundation (to Y.N.) and The Uehara Memorial Foundation (to Y.N.)

Five isoforms of the phosphatidylinositol 3-kinase regulatory subunit exhibit different associations with receptor tyrosine kinases and their tyrosine phosphorylations

AbstractThere are five isoforms of the regulatory subunit for the heterodimeric type of phosphatidylinositol 3-kinase. These five regulatory subunit isoforms were overexpressed using an adenovirus transfection system, and their own tyrosine phosphorylations and associations with various tyrosine kinase receptors were investigated. When overexpressed in CHO-PDGFR cells, the associations of these regulatory subunit isoforms with the platelet-derived growth factor receptor were similar. However, when overexpressed in CHO-IR cells, p55γ exhibited a significantly lower ability to bind with IRS-1 upon insulin stimulation, as compared with other regulatory subunit isoforms. Furthermore, p55α and p55γ were found to be tyrosine-phosphorylated. Finally, interestingly, when overexpressed in CHO-EGFR cells or A431 cells and stimulated with epidermal growth factor (EGF), phosphorylated EGF receptor was detected in p85α, p85β and p50α immunoprecipitates, but not in p55α and p55γ immunoprecipitates. In addition, EGF-induced tyrosine phosphorylation was observed in p85α, p85β, p55α and p55γ, but not in p50α, immunoprecipitates. Thus, each regulatory subunit exhibits specific responses regarding both the association with tyrosine-phosphorylated substrates and its own tyrosine phosphorylation. These results suggest that each isoform possesses specific roles in signal transduction, based on its individual tyrosine kinase receptor

Palmitoylation of the canine histamine H2 receptor occurs at Cys305 and is important for cell surface targeting

AbstractTo determine the presence and functional role of the histamine H2 receptor (H2R) palmitoylation, a receptor with a Cys305 to Ala (A305 receptor) mutation was generated. Wild-type (WT) and A305 receptors were tagged at their N-termini with a hemagglutinin (HA) epitope. WT, but not A305, receptors incorporated [3H]palmitate by metabolic labeling, indicating that the H2R is palmitoylated at Cys305. Immunocytochemistry of WT and A305 receptors expressed in COS7 cells revealed WT receptors to be distributed at the plasma membrane, while the majority of A305 receptors were localized intracellularly with only a small portion being at the plasma membrane. However, the affinity of the A305 receptor for tiotidine was comparable to that of the WT receptor. In addition, when the amounts of cell surface receptors as determined by anti-HA antibody binding were equivalent, A305 receptors mediated production of more cAMP than WT receptors. Preincubation of COS7 cells expressing each receptor with 10−5 M histamine for 30 min reduced subsequent cAMP production in response to histamine via the receptors to similar extents, indicating that palmitoylation is not necessary for desensitization. In addition, cell surface A305 receptors were capable of being internalized from the cell surface at a rate and extent similar to those of WT receptors. Finally, CHO cell lines stably expressing either WT or A305 receptors were incubated with 10−5 M histamine for 1, 6, 12 and 24 h. Total amounts of WT and A305 receptors, as determined by tiotidine binding, were reduced by incubation, indicating downregulation. Downregulation of the A305 receptor was more extensive than that of the WT receptor. Thus, palmitoylation of the H2R might be important for targeting to the cell surface and stability

A Model for the 3He(\vec d, p)4He Reaction at Intermediate Energies

Polarization correlation coefficients have been measured atRIKEN for the \vec 3He(\vec d,p)4He reaction at intermediate energies. We propose a model for the (\vec d, p) reaction mechanism using the pd elastic scattering amplitude which is rigorously determined by a Faddeev calculation and using modern NN forces. Our theoretical predictions for deuteron polarization observables A_y, A_{yy}, A_{xx} and A_{xz} at E_d=140, 200 and 270 MeV agree qualitatively in shape with the experimental data for the reaction 3He(\vec d,p)4He.Comment: 6 pages, 11 figures, 1 table, reference: http://www.phys.ntu.edu.tw/english/fb16/contribution/topic4/Uesaka_Tomohiro1. ps in Contribution for the XVIth IUPAP International Conference on Few-Body Problems in Physics, (Taipei, Taiwan 6-11, March 2000

Involvement of resistin-like molecule β in the development of methionine-choline deficient diet-induced non-alcoholic steatohepatitis in mice

Resistin-like molecule β (RELMβ) reportedly has multiple functions including local immune responses in the gut. In this study, we investigated the possible contribution of RELMβ to non-alcoholic steatohepatitis (NASH) development. First, RELMβ knock-out (KO) mice were shown to be resistant to methionine-choline deficient (MCD) diet-induced NASH development. Since it was newly revealed that Kupffer cells in the liver express RELMβ and that RELMβ expression levels in the colon and the numbers of RELMβ-positive Kupffer cells were both increased in this model, we carried out further experiments using radiation chimeras between wild-type and RELMβ-KO mice to distinguish between the contributions of RELMβ in these two organs. These experiments revealed the requirement of RELMβ in both organs for full manifestation of NASH, while deletion of each one alone attenuated the development of NASH with reduced serum lipopolysaccharide (LPS) levels. The higher proportion of lactic acid bacteria in the gut microbiota of RELMβ-KO than in that of wild-type mice may be one of the mechanisms underlying the lower serum LPS level the former. These data suggest the contribution of increases in RELMβ in the gut and Kupffer cells to NASH development, raising the possibility of RELMβ being a novel therapeutic target for NASH

Effect of surface roughness of biomaterials on Staphylococcus epidermidis adhesion

Background: Implant-related infections are caused by adhesion of bacteria to the surface of biomaterials. In this in vitro research, we evaluated the ability of Staphylococcus epidermidis (ATCC35984) to adhere to the surface of solid biomaterials at different levels of roughness below 30 nm Ra and investigated the minimum level of roughness required to promote bacterial adhesion on five kinds of biomaterials: oxidized zirconium-niobium alloy (Oxinium), cobalt-chromium-molybdenum alloy (Co-Cr-Mo), titanium alloy (Ti-6Al-4 V), commercially pure titanium (Cp-Ti) and stainless steel (SUS316L), samples of which were categorized into a fine group and a coarse group according to surface roughness. The test specimens were physically analyzed and the viable bacterial density of the adhered bacteria was quantitatively determined (n = 20).Results: The amount of bacteria that adhered to the biomaterials in the coarse group was higher than those in the fine group. Oxinium, Ti-6Al-4 V and SUS316L in particular demonstrated statistically significant differences between the two groups (P < 0.05). Of the materials, the Co-Cr-Mo specimens exhibited significantly lower amounts of adhered bacteria than the Ti-6Al-4 V, Cp-Ti and SUS316L specimens in the fine group. Similarly, the Co-Cr-Mo specimens in the coarse group exhibited significantly lower values than the other four materials.Conclusions: These results suggest that minimum level of roughness affecting initial bacterial adherence activity differs according to the type of biomaterial used, and that even a surface roughness of below 30 nm Ra in Oxinium, Ti-6Al-4 V and SUS316L can promote bacterial adhesion. Relative hydrophobic Co-Cr-Mo surfaces were less susceptible to bacterial adherence

Early Staphylococcal Biofilm Formation on Solid Orthopaedic Implant Materials: In Vitro Study

Biofilms forming on the surface of biomaterials can cause intractable implant-related infections. Bacterial adherence and early biofilm formation are influenced by the type of biomaterial used and the physical characteristics of implant surface. In this in vitro research, we evaluated the ability of Staphylococcus epidermidis, the main pathogen in implant-related infections, to form biofilms on the surface of the solid orthopaedic biomaterials, oxidized zirconium-niobium alloy, cobalt-chromium-molybdenum alloy (Co-Cr-Mo), titanium alloy (Ti-6Al-4V), commercially pure titanium (cp-Ti) and stainless steel. A bacterial suspension of Staphylococcus epidermidis strain RP62A (ATCC35984) was added to the surface of specimens and incubated. The stained biofilms were imaged with a digital optical microscope and the biofilm coverage rate (BCR) was calculated. The total amount of biofilm was determined with the crystal violet assay and the number of viable cells in the biofilm was counted using the plate count method. The BCR of all the biomaterials rose in proportion to culture duration. After culturing for 2-4 hours, the BCR was similar for all materials. However, after culturing for 6 hours, the BCR for Co-Cr-Mo alloy was significantly lower than for Ti-6Al-4V, cp-Ti and stainless steel (P0.05). These results suggest that surface properties, such as hydrophobicity or the low surface free energy of Co-Cr-Mo, may have some influence in inhibiting or delaying the two-dimensional expansion of biofilm on surfaces with a similar degree of smoothness