Diabetes-Related Ankyrin Repeat Protein (DARP/Ankrd23) Modifies Glucose Homeostasis by Modulating AMPK Activity in Skeletal Muscle.

Skeletal muscle is the major site for glucose disposal, the impairment of which closely associates with the glucose intolerance in diabetic patients. Diabetes-related ankyrin repeat protein (DARP/Ankrd23) is a member of muscle ankyrin repeat proteins, whose expression is enhanced in the skeletal muscle under diabetic conditions; however, its role in energy metabolism remains poorly understood. Here we report a novel role of DARP in the regulation of glucose homeostasis through modulating AMP-activated protein kinase (AMPK) activity. DARP is highly preferentially expressed in skeletal muscle, and its expression was substantially upregulated during myotube differentiation of C2C12 myoblasts. Interestingly, DARP-/- mice demonstrated better glucose tolerance despite similar body weight, while their insulin sensitivity did not differ from that in wildtype mice. We found that phosphorylation of AMPK, which mediates insulin-independent glucose uptake, in skeletal muscle was significantly enhanced in DARP-/- mice compared to that in wildtype mice. Gene silencing of DARP in C2C12 myotubes enhanced AMPK phosphorylation, whereas overexpression of DARP in C2C12 myoblasts reduced it. Moreover, DARP-silencing increased glucose uptake and oxidation in myotubes, which was abrogated by the treatment with AICAR, an AMPK activator. Of note, improved glucose tolerance in DARP-/- mice was abolished when mice were treated with AICAR. Mechanistically, gene silencing of DARP enhanced protein expression of LKB1 that is a major upstream kinase for AMPK in myotubes in vitro and the skeletal muscle in vivo. Together with the altered expression under diabetic conditions, our data strongly suggest that DARP plays an important role in the regulation of glucose homeostasis under physiological and pathological conditions, and thus DARP is a new therapeutic target for the treatment of diabetes mellitus

Neutrophil and lymphocyte responses to oral Streptococcus in Adamantiades-Behcet's disease

Immune reactions against microorganisms play an important pathogenic role in Adamantiades-Behçet’s disease (ABD). We had previously obtained Streptococcus sanguinis (strain BD113-20) isolated from the oral cavity of patients with ABD. To investigate the pathogenesis of this isolate, we examined neutrophil 5 reactions and level of cytokine production by lymphocytes after stimulation with the strain. The reactions of neutrophils were examined by chemiluminescence assay using whole blood. The amounts of interferon gamma (IFN-g) and interleukin (IL)-4, IL-8, IL-10, and IL-12 produced by peripheral blood mononuclear cells (PBMCs) were measured by ELISA. 10 Strain BD113-20 activated neutrophils from patients with ABD and healthy volunteers, and, in addition it increased IFN-g production by lymphocytes. Lymphocyte from the patients with ABD showed a dominant T helper 1 (Th-1) immune response. Results indicated that both bacterial stimulation and host hypersensitivity might be involved in the symptoms and pathogenesis of ABD

Oligomerization of Hepatitis C Virus Core Protein is Crucial for Interaction with the Cytoplasmic Domain of E1 Envelope Protein

Hepatitis C virus (HCV) contains two membrane-associated envelope glycoproteins, E1 and E2, which assemble as a heterodimer in the endoplasmic reticulum (ER). In this study, predictive algorithms and genetic analyses of deletion mutants and glycosylation site variants of the E1 glycoprotein were used to suggest that the glycoprotein can adopt two topologies in the ER membrane: the conventional type I membrane topology and a polytopic topology in which the protein spans the ER membrane twice with an intervening cytoplasmic loop (amino acid residues 288 to 360). We also demonstrate that the E1 glycoprotein is able to associate with the HCV core protein, but only upon oligomerization of the core protein in the presence of tRNA to form capsid-like structures. Yeast two-hybrid and immunoprecipitation analyses reveal that oligomerization of the core protein is promoted by amino acid residues 72 to 91 in the core. Furthermore, the association between the E1 glycoprotein and the assembled core can be recapitulated using a fusion protein containing the putative cytoplasmic loop of the E1 glycoprotein. This fusion protein is also able to compete with the intact E1 glycoprotein for binding to the core. Mutagenesis of the cytoplasmic loop of E1 was used to define a region of four amino acids (residues 312 to 315) that is important for interaction with the assembled HCV core. Taken together, our studies suggest that interaction between the self-oligomerized HCV core and the E1 glycoprotein is mediated through the cytoplasmic loop present in a polytopic form of the E1 glycoprotein

根治切除後の結腸癌StageⅡ、StageⅢ、及び大腸癌肝転移における原発部位が与える影響

Purpose: Primary tumor location of colon cancer has been reported to affect the prognosis after curative resection. However, some reports suggested the impact was varied by tumor stage. This study analyzed the prognostic impact of the sidedness of colon cancer in stages II, III, and liver metastasis after curative resection using propensity-matched analysis. Methods: Right-sided colon cancer was defined as a tumor located from cecum to splenic flexure, while any more distal colon cancer was defined as left-sided colon cancer. Patients who underwent curative resection at Nara Medical University hospital between 2000 and 2016 were analyzed. Results: There were 110 patients with stage II, 100 patients with stage III, and 106 patients with liver metastasis. After propensity matching, 28 pairs with stage II and 32 pairs with stage III were identified. In the patients with stage II, overall survival (OS) and recurrence-free survival (RFS) were not significantly different for right- and left-sided colon cancers. In the patients with stage III, OS and RFS were significantly worse in right-sided colon cancer. In those with liver metastasis, OS of right-sided colon cancer was significantly worse than left-sided disease, while RFS was similar. Regarding metachronous liver metastasis, the difference was observed only in the patients whose primary colon cancer was stage III. In each stage, significantly higher rate of peritoneal recurrence was found in those with right-sided colon cancer. Conclusion: Sidedness of colon cancer had a significant and varied prognostic impact in patients with stage II, III, and liver metastasis after curative resection.博士（医学）・乙第1495号・令和3年3月15日Copyright © 2021 The Korean Society of Coloproctology.This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited

Platelets Strongly Induce Hepatocyte Proliferation with IGF-1 and HGF In Vitro

Background. It is well known that platelets have athrombotic effect. However, platelets play an importantrole not only in hemostasis but also in woundhealing and tissue regeneration. Platelets have beenreported to accumulate in the liver and promote liverregeneration after an extended hepatectomy, but themechanism is unclear. The present study was designedto clarify the mechanism by which plateletshave a direct proliferative effect on hepatocytes invitro.Materials and methods. Hepatocytes obtained frommale BALB/c mice by collagenase digestion and immortalizedhepatocytes (TLR2) were used. To elucidatethe mechanism of the proliferative effect of platelets,DNA synthesis of hepatocytes was measuredunder various conditions and the related cellular signalswere analyzed. Chromatographic analysis wasalso performed to clarify which elements of plateletshave mitogenic activity.Results. DNA synthesis significantly increased in thehepatocytes cultured with platelets (P < 0.001). However,when the platelets and hepatocytes were separated,the platelets did not have a proliferative effect.Whole disrupted platelets, the supernatant fraction,and fresh isolated platelets had a similar proliferativeeffect, while the membrane fraction did not. After theaddition of platelets, both Akt and extracellularsignal-regulated kinases ERK1/2 were activated, butextracellular signal-regulated kinase STAT3 was not activated. Some mitogenic fractions were obtainedfrom the platelet extracts by gel exclusion chromatography;the fractions were rich in hepatocyte growthfactor and IGF-1.Conclusions. Direct contact between platelets andhepatocytes was necessary for the proliferative effect.The direct contact initiated signal transduction involvedin growth factor activation. Hepatocyte growthfactor, vascular endothelial growth factor, and insulin-like growth factor-1, rather than platelet-derivedgrowth factor, mainly contributed to hepatocyteproliferation