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Type 2 diabetes is characterized by chronic hyperglycemia. Insulin, a hormone secreted from pancreatic β‐cells, decreases blood glucose levels, and glucagon, a hormone secreted from pancreatic α‐cells, increases blood glucose levels by counterregulation of insulin through stimulation of hepatic glucose production. In diabetic patients, dysregulation of glucagon secretion contributes to hyperglycemia. Thus, inhibition of the glucagon receptor is one strategy for the treatment of hyperglycemia in type 2 diabetes. In this paper, we report a series of biphenylsulfonamide derivatives that were designed, synthesized, and then evaluated by cAMP and hepatic glucose production assays as glucagon receptor antagonists. Of these, compound 7aB‐3 decreased glucagon‐induced cAMP production and glucagon‐induced glucose production in the in vitro assays. Glucagon challenge tests and glucose tolerance tests showed that compound 7aB‐3 significantly inhibited glucagon‐induced glucose increases and improved glucose tolerance. These results suggest that compound 7aB‐3 has therapeutic potential for the treatment of type 2 diabetes. [ABSTRACT FROM AUTHOR]

Background: Skeletal muscle atrophy is defined as a reduction of muscle mass caused by excessive protein degradation. However, the development of therapeutic interventions is still in an early stage. Although glucagon‐like peptide‐1 receptor (GLP‐1R) agonists, such as exendin‐4 (Ex‐4) and dulaglutide, are widely used for the treatment of diabetes, their effects on muscle pathology are unknown. In this study, we investigated the therapeutic potential of GLP‐1R agonist for muscle wasting and the mechanisms involved. Methods: Mouse C2C12 myotubes were used to evaluate the in vitro effects of Ex‐4 in the presence or absence of dexamethasone (Dex) on the regulation of the expression of muscle atrophic factors and the underlying mechanisms using various pharmacological inhibitors. In addition, we investigated the in vivo therapeutic effect of Ex‐4 in a Dex‐induced mouse muscle atrophy model (20 mg/kg/day i.p.) followed by injection of Ex‐4 (100 ng/day i.p.) for 12 days and chronic kidney disease (CKD)‐induced muscle atrophy model. Furthermore, we evaluated the effect of a long‐acting GLP‐1R agonist by treatment of dulaglutide (1 mg/kg/week s.c.) for 3 weeks, in DBA/2J‐mdx mice, a Duchenne muscular dystrophy model. Results: Ex‐4 suppressed the expression of myostatin (MSTN) and muscle atrophic factors such as F‐box only protein 32 (atrogin‐1) and muscle RING‐finger protein‐1 (MuRF‐1) in Dex‐treated C2C12 myotubes. The suppression effect was via protein kinase A and protein kinase B signalling pathways through GLP‐1R. In addition, Ex‐4 treatment inhibited glucocorticoid receptor (GR) translocation by up‐regulating the proteins of GR inhibitory complexes. In a Dex‐induced muscle atrophy model, Ex‐4 ameliorated muscle atrophy by suppressing muscle atrophic factors and enhancing myogenic factors (MyoG and MyoD), leading to increased muscle mass and function. In the CKD muscle atrophy model, Ex‐4 also increased muscle mass, myofiber size, and muscle function. In addition, treatment with a long‐acting GLP‐1R agonist, dulaglutide, recovered muscle mass and function in DBA/2J‐mdx mice. Conclusions: GLP‐1R agonists ameliorate muscle wasting by suppressing MSTN and muscle atrophic factors and enhancing myogenic factors through GLP‐1R‐mediated signalling pathways. These novel findings suggest that activating GLP‐1R signalling may be useful for the treatment of atrophy‐related muscular diseases. [ABSTRACT FROM AUTHOR]

Highlights from the article: Compounds B 4 b and B 6 b were also effective in scavenging activity, with IC SB 50 sb values of 74.2 M and 96.6 M, respectively. Homoisoflavonoids B 1 b , B 2 b , B 5 b , and B 7 b showed the IC SB 50 sb value more than 100 M. For peroxynitrite from decomposition of SIN-1, B 3 b exhibited the strongest scavenging activity with IC SB 50 sb value of 44.0 M. The scavenging activities of other homoisoflavonoids were decreased in the following orders: B 4 b (47.2 M) > B 6 b (54.2 M) > B 1 b (79.4 M) > B 7 b (87.5 M) > B 2 b , B 5 b (>100 M). The scavenging activities were represented in the following order: B 3 b > B 4 b > B 1 b > B 6 b > B 7 b . Compounds B 6 b and B 7 b exerted the good inhibitory effect of growth against AGS cells, with IC SB 50 sb values of 41.4 and 85.7 M, respectively.

Abstract: Mesenchymal stem cells (MSCs) have been investigated to treat liver diseases, but the efficiency of MSCs to treat chronic liver diseases is conflicting. FGF21 can reduce inflammation and fibrosis. We established FGF21‐secreting adipose derived stem cells (FGF21_ADSCs) to enhance the effects of ADSCs and transplanted them into thioacetamide (TAA)‐induced liver fibrosis mice via the tail vein. Transplantation of FGF21_ADSCs significantly improved liver fibrosis by decreasing serum hyaluronic acid and reducing the expression of fibrosis‐related factors such as α‐smooth muscle actin (α‐SMA), collagen and tissue inhibitor of metalloproteinase‐1 (TIMP‐1) compared with the Empty_ADSCs by inhibition of p‐JNK, NF‐κB and p‐Smad2/3 signalling. α‐lactoalbumin (LA) and lactotransferrin (LTF), secretory factors produced from FGF21_ADSCs inhibited TGF‐β1‐induced expression of α‐SMA and collagen in LX‐2 cells. These results suggest that transplantation of FGF21_ADSCs inhibited liver fibrosis more effectively than Empty_ADSCs, possibly via secretion of α‐LA and LTF. [ABSTRACT FROM AUTHOR]

Type 1 diabetes results from autoimmune-mediated pancreatic beta-cell destruction and transforming growth factor-beta (TGF-β) is known to play a preventive role in type 1 diabetes in non-obese diabetic (NOD) mice. In this study, we investigated the role of Smad4, a key molecule for Smad-dependent TGF-β signaling, in T cells of NOD mice in the pathogenesis of autoimmune diabetes. We generated T-cell-specific Smad4 knockout (Smad4 tKO) NOD mice and assessed the pathological and immunological changes. Smad4 tKO showed earlier onset and increased incidence of diabetes than wild type (WT) NOD mice. Pathological features such as insulitis, anti-glutamic acid decarboxylase auto-antibody levels and serum IFN-γ levels were significantly increased in Smad4 tKO compared with WT NOD mice. Proportion and number of activated/memory CD4+ T cell were significantly increased in pancreatic lymph nodes of Smad4 tKO compared with WT NOD mice. However, the proportion and function of regulatory T cells was not different. Effector CD4+ T cells from Smad4 tKO were more resistant to suppression by regulatory T cells than effector cells from WT NOD mice. The proliferative potential of effector T cells from Smad4 tKO was significantly elevated compared with WT NOD mice, and activation of sterol regulatory element binding protein-1c (SREBP-1c) in T cells of Smad4 tKO NOD mice was correlated with this proliferative activity. We conclude that Smad4 deletion in T cells of NOD mice accelerated the development of autoimmune diabetes and increased the incidence of the disease by dysregulation of T cell activation at least in part via SREBP-1c activation. [ABSTRACT FROM AUTHOR]

Background Type 2 diabetes is characterized by progressive beta-cell failure and apoptosis is probably the main form of beta-cell death in this disease. It was reported that circulating levels of interleukin-6 are elevated in type 2 diabetic patients, but whether this is involved in the pathogenesis of type 2 diabetes is still debated. In this study, we examined whether interleukin-6 can induce beta-cell damage in vitro and elucidated its mechanisms. Methods To examine the effect of interleukin-6 on beta cells, glucose-stimulated insulin secretion (GSIS) by enzyme immunoassay (EIA) method and cell apoptosis by propidium iodide and annexin-V staining were measured in a rat beta-cell line (INS-1 or INS-832/13) after treatment with interleukin-6. The expression of apoptosis-related molecules was measured using western blotting and nitric oxide (NO) production was measured using Griess assay. AG490 and N-monomethyl- L-arginine were used to inhibit Janus kinase-mediated signal transducers and activators of transcription signalling and NO production, respectively. Results Exposure (48 h) of INS-1 cells to 20 ng/mL interleukin-6 significantly decreased GSIS as well as cell viability. We found that sub-G1/G0 population was increased as compared with untreated cells and expression of cleaved caspase-3, cleaved poly(ADP-ribose) polymerase, phosphorylated p38 mitogen-activated protein kinase and phosphorylated nuclear factor-κB was increased in interleukin-6-treated INS-1 cells. Interleukin-6 increased the amount of early apoptotic cells; this increase was blocked by AG490 or N-monomethyl- L-arginine treatment. Moreover, NO production, which is known to induce apoptosis, was increased by interleukin-6 treatment but abrogated in AG490-treated cells. Conclusion Our results show that exposure to interleukin-6 for 48 h can induce beta-cell death, in part via signal transducers and activators of transcription-3-mediated NO production. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

More than 10 viruses have been reported to be associated with the development of type 1 diabetes-like symptoms in animals, with the best evidence coming from studies on the D variant of encephalomyocarditis (EMC-D) virus in mice and Kilham rat virus (KRV) in rats. A high titer of EMC-D viral infection results in the development of diabetes within 3 days, primarily due to the rapid destruction of β cells by viral replication within the cells. A low titer of EMC-D viral infection results in the recruitment of macrophages to the islets. Soluble mediators produced by activated macrophages play a critical role in the destruction of residual β cells. A single amino acid at position 776 of the EMC viral genome controls the diabetogenicity of the virus. In contrast, KRV causes autoimmune type 1 diabetes in diabetes-resistant BioBreeding (DR-BB) rats without direct infection of β cells. Macrophages play an important role in the development of diabetes in KRV-infected DR-BB rats. As well, KRV infection preferentially activates effector T cells, such as Th1-like CD45RC+CD4+ T cells and CD8+ T cells, and downregulates regulatory T cells, such as Th2-like CD45RC−CD4+ T cells. This results in the breakdown of the immune balance, contributing to the development of diabetes in KRV-infected DR-BB rats. [ABSTRACT FROM AUTHOR]

Aging is a major risk factor for many chronic diseases due to increased vulnerability to external stress and susceptibility to disease. Aging is associated with metabolic liver disease such as nonalcoholic fatty liver. In this study, we investigated changes in lipid metabolism during aging in mice and the mechanisms involved. Lipid accumulation was increased in liver tissues of aged mice, particularly cholesterol. Increased uptake of both cholesterol and glucose was observed in hepatocytes of aged mice as compared with younger mice. The mRNA expression of GLUT2, GK, SREBP2, HMGCR, and HMGCS, genes for cholesterol synthesis, was gradually increased in liver tissues during aging. Reactive oxygen species (ROS) increase with aging and are closely related to various aging‐related diseases. When we treated HepG2 cells and primary hepatocytes with the ROS inducer, H2O2, lipid accumulation increased significantly compared to the case for untreated HepG2 cells. H2O2 treatment significantly increased glucose uptake and acetyl‐CoA production, which results in glycolysis and lipid synthesis. Treatment with H2O2 significantly increased the expression of mRNA for genes related to cholesterol synthesis and uptake. These results suggest that ROS play an important role in altering cholesterol metabolism and consequently contribute to the accumulation of cholesterol in the liver during the aging process. [ABSTRACT FROM AUTHOR]

Objective: Results of recent studies suggest that human chorionic gonadotropin (HCG), a placental glycoprotein hormone required for the maintenance of pregnancy, may have immunomodulatory properties. Primary Sjögren's syndrome (SS), a chronic autoimmune disorder of unknown etiology, affects multiple exocrine glands including the salivary and lacrimal glands. The purpose of the present study was to determine whether HCG could prevent the development of salivary gland exocrinopathy in NOD mice, an experimental model of Sjögren's-like syndrome., Methods: Female NOD mice were treated with HCG from 6 weeks of age to 12 weeks of age. At 14 weeks, tissue samples were evaluated for inflammatory lesions and cytokine messenger RNA by real-time polymerase chain reaction. At 18 weeks, the salivary flow rate was measured., Results: Treatment with HCG resulted in a significant decrease in lymphocyte infiltration and parenchymal cell damage in the submandibular salivary glands. Messenger RNA levels of interferon-gamma, tumor necrosis factor alpha, interleukin-1beta, and interleukin-10, as well as inducible nitric oxide synthase and matrix metalloproteinase 9, were significantly decreased. Function studies revealed a marked increase in the salivary flow rate in HCG-treated mice compared with that in phosphate buffered saline-treated mice., Conclusion: In NOD mice, HCG acts as an immune modulator and prevents the development of salivary gland exocrinopathy. These findings suggest that HCG, a naturally occurring reproductive hormone, may be useful in the treatment of Sjögren's syndrome and other human autoimmune diseases.