BackgroundGlycosuria produced by sodium–glucose co-transporter-2 (SGLT-2) inhibitors is associated with weight loss. SGLT-2 inhibitors reportedly might reduce the occurrence of cardiovascular events. Epicardial adipose tissue (EAT) is a pathogenic fat depot that may be associated with coronary atherosclerosis. The present study evaluated the relationship between an SGLT-2 inhibitor (dapagliflozin) and EAT volume.MethodsIn 40 diabetes mellitus patients with coronary artery disease (10 women and 30 men; mean age of all 40 patients was 67.2 ± 5.4 years), EAT volume was compared prospectively between the dapagliflozin treatment group (DG; n = 20) and conventional treatment group (CTG; n = 20) during a 6-month period. EAT was defined as any pixel that had computed tomography attenuation of − 150 to − 30 Hounsfield units within the pericardial sac. Metabolic parameters, including HbA1c, tumor necrotic factor-α (TNF-α), and plasminogen activator inhibitor-1 (PAI-1) levels, were measured at both baseline and 6-months thereafter.ResultsThere were no significant differences at baseline of EAT volume and HbA1c, PAI-1, and TNF-α levels between the two treatment groups. After a 6-month follow-up, the change in HbA1c levels in the DG decreased significantly from 7.2 to 6.8%, while body weight decreased significantly in the DG compared with the CTG (− 2.9 ± 3.4 vs. 0.2 ± 2.4 kg, p = 0.01). At the 6-month follow-up, serum PAI-1 levels tended to decline in the DG. In addition, the change in the TNF-α level in the DG was significantly greater than that in the CTG (− 0.5 ± 0.7 vs. 0.03 ± 0.3 pg/ml, p = 0.03). Furthermore, EAT volume significantly decreased in the DG at the 6-month follow-up compared with the CTG (− 16.4 ± 8.3 vs. 4.7 ± 8.8 cm3, p = 0.01). Not only the changes in the EAT volume and body weight, but also those in the EAT volume and TNF-α level, showed significantly positive correlation.ConclusionTreatment with dapagliflozin might improve systemic metabolic parameters and decrease the EAT volume in diabetes mellitus patients, possibly contributing to risk reduction in cardiovascular events.
Various cytokines utilize Janus kinase (JAK) and the STAT (signal transducers and activators of transcription) family of transcription factors to carry out their biological functions. Among STATs, two highly related proteins, STAT5a and STAT5b, are activated by various cytokines, including prolactin, growth hormone, erythropoietin, interleukin 2 (IL-2), and IL-3. We have cloned a STAT5-dependent immediate-early cytokine-responsive gene, CIS1 (encoding cytokine-inducible SH2-containing protein 1). In this study, we created CIS1 transgenic mice under the control of a beta-actin promoter. The transgenic mice developed normally; however, their body weight was lower than that of the wild-type mice, suggesting a defect in growth hormone signaling. Female transgenic mice failed to lactate after parturition because of a failure in terminal differentiation of the mammary glands, suggesting a defect in prolactin signaling. The IL-2-dependent upregulation of the IL-2 receptor alpha chain and proliferation were partially suppressed in the T cells of transgenic mice. These phenotypes remarkably resembled those found in STAT5a and/or STAT5b knockout mice. Indeed, STAT5 tyrosine phosphorylation was suppressed in mammary glands and the liver. Furthermore, the IL-2-induced activation of STAT5 was markedly inhibited in T cells in transgenic mice, while leukemia inhibitory factor-induced STAT3 phosphorylation was not affected. We also found that the numbers of gamma delta T cells, as well as those of natural killer (NK) cells and NKT cells, were dramatically decreased and that Th1/Th2 differentiation was altered in transgenic mice. These data suggest that CIS1 functions as a specific negative regulator of STAT5 in vivo and plays an important regulatory role in the liver, mammary glands, and T cells.
The complement system membrane cofactor protein (MCP) CD46 serves as a C3b/C4b inactivating factor for the protection of host cells from autologous complement attack and as a receptor for measles virus (MV). MCP consists of four short consensus repeats (SCR) which are the predominant extracellular structural motif. In the present study, we determined which of the four SCR of MCP contribute to its function using Chinese hamster ovary cell clones expressing each SCR deletion mutants. The results were as follows: 1) SCR1 and SCR2 are mainly involved in MV binding and infection; 2) SCR2, SCR3, and SCR4 contribute to protect Chinese hamster ovary cells from human alternative complement pathway-mediated cytolysis; and 3) SCR2 and SCR3 are essential for protection of host cells from the classical complement pathway. These results on cell protective activity of the mutants against the human classical and the alternative complement pathways were compatible with factor I-mediated inactivation profiles of C4b and C3b, respectively, in the fluid-phase assay using solubilized mutants and factor I; the results were mostly consistent with those reported by Adams et al. (Adams, E. M., Brown, M. C., Nunge, M., Krych, M., and Atkinson, J. P. (1991) J. Immunol. 147, 3005-3011). SCR2 and SCR3 were required for C3b and C4b inactivation, and SCR4-deleted MCP showed weak cofactor activity for C4b cleavage but virtually no cofactor activity for C3b cleavage. The functional domains of MCP for the three natural ligands C3b, C4b, and MV, therefore, map to different, although partly overlapping, SCR domains.
RIG-I-mediated type I interferon (IFN) production and nuclease-mediated viral RNA degradation are essential for antiviral innate immune responses. DDX60 is an IFN-inducible cytoplasmic helicase. Here, we report that DDX60 is a sentinel for both RIG-I activation and viral RNA degradation. We show that DDX60 is an upstream factor of RIG-I that activates RIG-I signaling in a ligand-specific manner. DDX60 knockout attenuates RIG-I signaling and significantly reduces virus-induced type I IFN production in vivo. In addition, we show that DDX60 is involved in RIG-I-independent viral RNA degradation. DDX60 and RIG-I adaptor MAVS double-knockout mice reveal a role for DDX60-dependent RNA degradation in antiviral responses. Several viruses induced DDX60 phosphorylation via epidermal growth factor receptor (EGFR), leading to attenuation of the DDX60 antiviral activities. Our results define DDX60 as a sentinel for cytoplasmic antiviral response, which is counteracted by virus-mediated EGF receptor activation.
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