Water Extract of Pleurotus eryngii var. ferulae Prevents High-Fat Diet-Induced Obesity by Inhibiting Pancreatic Lipase.

Pleurotus eryngii var. ferulae (PEF) is traditionally used in the prevention and treatment of lifestyle-related diseases. In this study, we investigated the ability of PEF extract to prevent obesity and metabolic diseases and explored the underlying mechanism. Mice were fed a high-fat diet (HFD) containing PEF extract for 12 weeks, and their body weight, adipose tissue and liver weights, and lipid profiles and blood glucose levels, were monitored. Fecal triglyceride (TG) levels were also measured and olive oil-loading tests were performed. Furthermore, the effect of PEF extract on pancreatic lipase (PL) activity was examined in vitro. Treatment with PEF extract for 12 weeks resulted in a significant decrease in the HFD-induced increases in body weight, white adipose tissue weight, liver weights, and lipid profiles, and improved glucose tolerance and insulin sensitivity. To assess the mechanism underlying the effect of PEF extract on obesity and diabetes, we investigated its role in inhibiting lipid absorption. Consumption of an HFD containing PEF extract significantly increased the TG level in feces compared with the controls, suggesting inhibition of TG absorption in the digestive tract. Furthermore, PEF extract suppressed the increase in serum TG levels resulting from oral administration of a lipid emulsion to mice, confirming inhibition of TG absorption. Moreover, PEF extract inhibited PL activity in vitro. Our combined results indicate that the anti-obesity and antidiabetic effect of PEF extract in mice fed an HFD may be caused by inhibition of lipid absorption as a result of reduced PL activity.

Inhibition of C1-Ten PTPase activity reduces insulin resistance through IRS-1 and AMPK pathways.

Insulin resistance causes type 2 diabetes; therefore, increasing insulin sensitivity is a therapeutic approach against type 2 diabetes. Activating AMP-activated protein kinase (AMPK) is an effective approach for treating diabetes, and reduced insulin receptor substrate-1 (IRS-1) protein levels have been suggested as a molecular mechanism causing insulin resistance. Thus, dual targeting of AMPK and IRS-1 might provide an ideal way to treat diabetes. We found that 15,16-dihydrotanshinone I (DHTS), as a C1-Ten protein tyrosine phosphatase inhibitor, increased IRS-1 stability, improved glucose tolerance and reduced muscle atrophy. Identification of DHTS as a C1-Ten inhibitor revealed a new function of C1-Ten in AMPK inhibition, possibly through regulation of IRS-1. These findings suggest that C1-Ten inhibition by DHTS could provide a novel therapeutic strategy for insulin resistance-associated metabolic syndrome through dual targeting of IRS-1 and AMPK.

Potential pancreatic lipase inhibitory activity of phenolic constituents from the root bark of Morus alba L.

Detailed phytochemical investigation from the root bark of Morus alba resulted in the isolation of eleven new compounds, including seven 2-arylbenzofuran derivatives (morusalfurans A-G), three flavonoids (morusalnols A-C), and one geranylated stilbene (morusibene A), as well as 22 known compounds. The structures of the identified compounds were elucidated based on a comprehensive analysis of spectroscopic data and Mosher's method. Compounds 2, 3, 6-8, 11, 23, 24, and 29 showed potent inhibition of PL in comparison with the positive control treatment (orlistat, IC50=0.012µM), with IC50 values ranging from 0.09 to 0.92µM.

DISTINCTIVE LOCALIZATION OF GROUP 3 LATE EMBRYOGENESIS ABUNDANT SYNTHESIZING CELLS DURING BRINE SHRIMP DEVELOPMENT.

Despite numerous studies on late embryogenesis abundant (LEA) proteins, their functions, roles, and localizations during developmental stages in arthropods remain unknown. LEA proteins protect crucial proteins against osmotic stress during the development and growth of various organisms. Thus, in this study, fluorescence in situ hybridization was used to determine the crucial regions protected against osmotic stress as well as the distinctive localization of group 3 (G3) LEA(+) cells during brine shrimp development. Several cell types were found to synthesize G3 LEA RNA, including neurons, muscular cells, APH-1(+) cells, and renal cells. The G3 LEA(+) neuronal cell bodies outside of the mushroom body projected their axonal bundles to the central body, but those inside the mushroom body projected their axonal bundles toward the deutocerebrum without innervating the central body. The cell bodies inside the mushroom body received axons of the G3 LEA(+) sensory cells at the medial ventral cup of the nauplius eye. Several glands were found to synthesize G3 LEA RNA during the nauplius stages of brine shrimp, including the sinus, antennal I and II, salt, and three ectodermal glands. This study provides the first demonstration of the formation of G3 LEA(+) sinus glands at the emergence stages of brine shrimp. These results suggest that G3 LEA protein is synthesized in several cell types. In particular, specific glands play crucial roles during the emergence and nauplius stages of brine shrimp.

Exendin-4 increases bone mineral density in type 2 diabetic OLETF rats potentially through the down-regulation of SOST/sclerostin in osteocytes.

AIM: Glucagon-like peptide-1 (GLP-1) receptor participates in the control of bone resorption in GLP-1 knockout mice. Also, GLP-1 induces an insulin- and parathyroid hormone-independent osteogenic action through osteoclasts and osteoblasts in insulin-resistant and type 2 diabetic rats. Osteocytes are now considered central to bone homeostasis. A secreted product of osteocytes, sclerostin, inhibits bone formation. However, the effect of GLP-1 on osteocytes remains unclear. Therefore, we investigated the effect of GLP-1 on bone mineral density (BMD), and the cellular and molecular mechanisms associated with osteocytes. MAIN METHODS: We investigated the presence of GLP-1 receptors in osteocyte-like MLO-Y4 cells and osteocytes of rat femurs through RT-PCR, Western blot and confocal microscopy, and investigated the effect of exendin-4 on the expression of mRNA (by quantitative real-time RT-PCR) and protein (by Western blot) of SOST/sclerostin in osteocyte-like MLO-Y4 cells during culture under normal or high-glucose (30 mM) conditions, and measured circulating levels of sclerostin, osteocalcin, and tartrate-resistant alkaline phosphatase (TRAP) 5b and femoral BMD in type 2 diabetic OLETF rats treated with exendin-4. KEY FINDINGS: GLP-1 receptor was present on MLO-Y4 cells and osteocytes of rat femurs. Exendin-4 reduced the mRNA expression and protein production of SOST/sclerostin under normal or high-glucose conditions in MLO-Y4 cells. Exendin-4 reduced serum levels of sclerostin, increased serum levels of osteocalcin, and increased femoral BMD in type 2 diabetic OLETF rats. SIGNIFICANCE: These findings suggest that exendin-4 might increase BMD by decreasing the expression of SOST/sclerostin in osteocytes in type 2 diabetes.

17ß-estradiol induces an interaction between adenosine monophosphate-activated protein kinase and the insulin signaling pathway in 3T3-L1 adipocytes.

Estrogen (17ß-estradiol) has been implicated in maintaining insulin sensitivity. It is thought to act predominantly through genomic pathways and regulate the expression of various genes via binding to estrogen receptors (ERs)-α and -ß. 17ß-estradiol has been reported to simultaneously stimulate protein kinase B (Akt) and adenosine monophosphate-activated protein kinase (AMPK) in ex vivo skeletal muscle. Since data regarding the interaction between AMPK and the insulin receptor substrate-1 (IRS-1)/Akt pathway are controversial, the correlation between AMPK activation and insulin signaling remains unclear. In this study, we examined whether 17ß-estradiol simultaneously stimulates the activation of AMPK and IRS-1/Akt in 3T3-L1 adipocytes as well as the 17ß-estradiol-ER-induced interaction between the AMPK and IRS-1/Akt pathway in 3T3-L1 adipocytes not exposed to insulin. 17ß-estradiol (10⁻7 M) rapidly activated AMPK and IRS-1/Akt in 3T3-L1 adipocytes, while the ER-α/ß non-specific antagonist, ICI 182.780 (10 µM), and the AMPK antagonist compound C (20 µM) reversed the estrogen-induced activation of AMPK and tyrosine (Tyr)-IRS-1/Akt in these cells. Moreover, 17ß-estradiol increased the expression of the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α), adiponectin, uncoupling protein 2 (UCP2) and glucose transporter 4 (GLUT4) genes 24 h after treatment, whereas the ER-α/ß non-specific antagonist, ICI 182.780 (10 µM), and the AMPK antagonist compound C (20 µM) reversed the estrogen-induced increase in the expression of these genes. These results indicate that 17ß-estradiol activates AMPK through an ER and activates Akt through AMPK activation in 3T3-L1 adipocytes, despite the absence of insulin. Furthermore, 17ß-estradiol regulates the expression of genes related to glucose metabolism through ER-AMPK activation in these cells.

Melatonin improves inflammatory cytokine profiles in lung inflammation associated with sleep deprivation.

Sleep disturbance has become an endemic behavior in modern countries, and its prevalence has also increased. Even a subtle sleep deficiency is related to health problems. Particularly, patients with pulmonary disease often complain of insomnia. We recently showed that sleep deprivation (SD) exacerbates existing acute lung inflammation, and that melatonin treatment attenuates it via anti-apoptotic and anti-oxidant action. In order to reinforce our previous report, the present study was designed to evaluate pro-inflammatory mediators in acute lung inflammation in SD mice. In addition, we investigated the infiltration of inflammatory cells into the lungs. Twenty-five ICR mice were divided into 5 groups (n=5/group): control, SD, lipopolysaccharide (LPS), LPS + SD and LPS + SD + melatonin. The SD mice were deprived of sleep for 96 h in a multiplatform water bath. LPS (5 mg/kg) and melatonin (5 mg/kg) were administered on day 2. The mice were sacrificed on day 3, and serum and bronchoalveolar lavage (BAL) fluid were collected. The serum levels of inflammatory cytokines were increased in the LPS + SD group. Interleukin-6, tumor necrosis factor-α and interferon-γ levels were also increased in BAL fluid in the LPS + SD group. Melatonin reduced inflammatory mediators in the serum and BAL fluid. The accumulation of leukocytes in the LPS and LPS + SD mice was elevated, however, melatonin inhibited the recruitment of inflammatory cells (p<0.05). Lymphocytes in the BAL fluid of the LPS + SD group were increased, and macrophage levels were decreased; however, the increment was attenuated by melatonin administration (p<0.05). In conclusion, this study indicates that melatonin has a protective effect against lung inflammation associated with SD.

Exendin-4 protects oxidative stress-induced ß-cell apoptosis through reduced JNK and GSK3ß activity.

Oxidative stress induced by chronic hyperglycemia in type 2 diabetes plays a crucial role in progressive loss of ß-cell mass through ß-cell apoptosis. Glucagon like peptide-1 (GLP-1) has effects on preservation of ß-cell mass and its insulin secretory function. GLP-1 possibly increases islet cell mass through stimulated proliferation from ß-cell and differentiation to ß-cell from progenitor cells. Also, it probably has an antiapoptotic effect on ß-cell, but detailed mechanisms are not proven. Therefore, we examined the protective mechanism of GLP-1 in ß-cell after induction of oxidative stress. The cell apoptosis decreased to ~50% when cells were treated with 100 µM H(2)O(2) for up to 2 hr. After pretreatment of Ex-4, GLP-1 receptor agonist, flow cytometric analysis shows 41.7% reduction of ß-cell apoptosis. This data suggested that pretreatment of Ex-4 protect from oxidative stress-induced apoptosis. Also, Ex-4 treatment decreased GSK3ß activation, JNK phosphorylation and caspase-9, -3 activation and recovered the expression of insulin2 mRNA in ß-cell lines and secretion of insulin in human islet. These results suggest that Ex-4 may protect ß-cell apoptosis by blocking the JNK and GSK3ß mediated apoptotic pathway.

Parenteral 17beta-estradiol decreases fasting blood glucose levels in non-obese mice with short-term ovariectomy.

AIMS: long-term ovariectomy-induced metabolic changes such as insulin resistance and glucose intolerance might be caused directly by estrogen deficiency and may occur partly as secondary effects of obesity arising due to the orexigenic effects of estrogen deficiency. Long-term estrogen treatment prevented those by exerting anorexigenic and metabolic actions in ovariectomized mice. However, the effect of short-term estrogen treatment on glucose metabolism in mice with short-term ovariectomy, during which ovariectomy-induced obesity does not develop, is not yet clear. The aim of this study was to evaluate the effect of short-term parenteral 17beta-estradiol treatment on glucose metabolism and blood glucose levels in mice at 2 weeks after ovariectomy, a time period during which ovariectomy-induced obesity does not develop. MAIN METHODS: we examined the effect of three 17beta-estradiol injections on fasting blood glucose levels, insulin resistance, components of the insulin signaling pathway, AMPK activation, and the expression of genes related to glucose metabolism in liver, skeletal muscle, and white adipose tissues of non-obese C57BL/6N mice with short-term ovariectomy. KEY FINDINGS: three 17beta-estradiol injections decreased the fasting blood glucose levels, activated AMPK, and decreased the expression of gluconeogenic genes, phosphoenolpyruvate carboxykinase, glucose-6-phosphatase and peroxisome proliferator-activated receptor-γ coactivator-1α in the liver. But three 17beta-estradiol injections did not affect insulin sensitivity and the components of the insulin signaling pathway in the liver and skeletal muscle. SIGNIFICANCE: short-term parenteral 17beta-estradiol treatment decreases the fasting blood glucose levels not via insulin sensitivity of the skeletal muscle in non-obese mice with short-term ovariectomy.

Methanolic extracts of Uncaria rhynchophylla induce cytotoxicity and apoptosis in HT-29 human colon carcinoma cells.

In this paper, we report the anticancer activities of Uncaria rhynchophylla extracts, a Rubiaceae plant native to China. Traditionally, Uncaria rhynchophylla has been used in the prevention and treatment of neurotoxicity. However, the cytotoxic activity of Uncaria rhynchophylla against human colon carcinoma cells has not, until now, been elucidated. We found that the methanolic extract of Uncaria rhynchophylla (URE) have cytotoxic effects on HT-29 cells. The URE showed highly cytotoxic effects via the MTT reduction assay, LDH release assay, and colony formation assay. As expected, URE inhibited the growth of HT-29 cells in a dose-dependent manner. In particular, the methanolic URE of the 500 microg/ml showed 15.8% inhibition against growth of HT-29 cells. It induced characteristic apoptotic effects in HT-29 cells, including chromatin condensation and sharking occurring 24 h when the cells were treated at a concentration of the 500 microg/ml. The activation of caspase-3 and the specific proteolytic cleavage of poly (ADP-ribose) polymerase were detected over the course of apoptosis induction. These results indicate that URE contains bioactive materials with strong activity, and is a potential chemotherapeutic agent candidate against HT-29 human colon carcinoma cells.