Effects of Extract from Solid-State Fermented Cordyceps sinensis on Type 2 Diabetes Mellitus.

Diabetes mellitus is the most common chronic disease in the world, and a wide range of drugs, including Chinese herbs, have been evaluated for the treatment of associated metabolic disorders. This study investigated the potential hypoglycemic and renoprotective effects of an extract from the solid-state fermented mycelium of Cordyceps sinensis (CS). We employed the KK/HIJ diabetic mouse model, in which the mice were provided with a high-fat diet for 8 weeks to induce hyperglycemia, followed by the administration of CS or rosiglitazone for 4 consecutive weeks. Several parameters were evaluated, including changes in body weight, plasma lipid profiles, oral glucose tolerance tests, insulin tolerance tests, and plasma insulin concentrations. Our results show that the CS extract significantly elevated HDL/LDL ratios at 4 weeks and decreased body weight gain at 8 weeks. Interestingly, CS treatment did not lead to obvious improvements in hyperglycemia or resistance to insulin, while in vitro MTT assays indicated that CS protects pancreatic beta cells against the toxic effects of STZ. CS also enhanced renal NKA activity and reduced the accumulation of mesangial matrix and collagen deposition. In conclusion, CS extract can potentially preserve ß-cell function and offer renoprotection, which may afford a promising therapy for DM.

The adjuvant effects of Antrodia Camphorata extracts combined with anti-tumor agents on multidrug resistant human hepatoma cells.

AIM OF THE STUDY: The objectives of this study were to investigate the adjuvant anti-tumor effects of Antrodia camphorate in human hepatoma cells (C3A and PLC/PRF/5) which are resistance to most anti-tumor agents, elucidate the possible regulation pathways, and measure the tumor growth and survival rate in xenograft-nude mice after combined with anti-tumor agents. MATERIALS AND METHODS: The AC extracts were measured by using a phenol/sulfuric acid method as previously described. The in vitro cell proliferation assay of ACs and anti-tumor agents was tested on C3A and PLC/PRF/5 cell lines. The percentage of human hepatoma cells undergoing apoptosis and distributing in different phases of cell cycle were determined by Flow cytometric analysis. Western blot analysis for MDR-1 and apoptosis- related proteins. The measurements of tumor growth and survival analysis of hepatoma implanted nude mice treated with Antrodia camphorata extracts and anti-tumor agents alone or in combinations. RESULTS: We have found that Antrodia camphorata extracts, when combined with anti-tumor agents, showed adjuvant antiproliferative effects on hepatoma cells (in vitro) and on xenografted cells in tumor-implanted nude mice (in vivo), which then extended their median survival days. Furthermore, solid-state extracts of Antrodia camphorata (AC-SS) showed its adjuvant effects through the inhibition of MDR gene expressions and the pathway of COX-2- dependent inhibition of p-AKT, which ultimately resulted in the induction of apoptosis in hepatoma cells. CONCLUSIONS: In this study, we have found that Antrodia camphorata extract, when combined with anti-tumor agents, showed adjuvant antiproliferative effects on hepatoma cells (in vitro) and on xenografted cells in tumor-implanted nude mice (in vivo).

Differential anti-diabetic effects and mechanism of action of charantin-rich extract of Taiwanese Momordica charantia between type 1 and type 2 diabetic mice.

Momordica charantia Linn. (Cucurbitaceae), also called bitter melon, has traditionally been used as a natural anti-diabetic agent for anti-hyperglycemic activity in several animal models and clinical trials. We investigated the differences in the anti-diabetic properties and mechanism of action of Taiwanese M. charantia (MC) between type 1 diabetic (T1D) and type 2 diabetic (T2D) mice. To clarify the beneficial effects of MC, we measured non-fasting glucose, oral glucose tolerance, and plasma insulin levels in KK/HIJ mice with high-fat diet-induced diabetes (200 mg/kg/day of charantin-rich extract of MC [CEMC]) and in ICR mice with STZ-induced diabetes. After 8 weeks, all the mice were exsanguinated, and the expression of the insulin-signaling-associated proteins in their tissue was evaluated, in coordination with the protective effects of CEMC against pancreatic ß-cell toxicity (in vitro). Eight weeks of data indicated that CEMC caused a significant decline in non-fasting blood glucose, plasma glucose intolerance, and insulin resistance in the KK/HIJ mice, but not in the ICR mice. Furthermore, CEMC decreased plasma insulin and promoted the sensitivity of insulin by increasing the expression of GLUT4 in the skeletal muscle and of IRS-1 in the liver of KK/HIJ mice; however, CEMC extract had no effect on the insulin sensitivity of ICR mice. In vitro study showed that CEMC prevented pancreatic ß cells from high-glucose-induced cytotoxicity after 24 h of incubation, but the protective effect was not detectable after 72 h. Collectively, the hypoglycemic effects of CEMC suggest that it has potential for increasing insulin sensitivity in patients with T2D rather than for protecting patients with T1D against ß-cell dysfunction.

Transcriptional activation of endoplasmic reticulum chaperone GRP78 by HCMV IE1-72 protein.

Glucose-regulated protein 78 (GRP78), a key regulator of endoplasmic reticulum (ER) stress, facilitates cancer cell growth and viral replication. The mechanism leading to grp78 gene activation during viral infection is largely unknown. In this study, we show that the immediate-early 1 (IE1-72) protein of the human cytomegalovirus (HCMV) is essential for HCMV-mediated GRP78 activation. IE1-72 upregulated grp78 gene expression depending on the ATP-binding site, the zinc-finger domain and the putative leucine-zipper motif of IE1-72, as well as the ER stress response elements (ERSEs) on the grp78 promoter. The purified IE1-72 protein bound to the CCAAT box within ERSE in vitro, whereas deletion mutants of IE1-72 deficient in grp78 promoter stimulation failed to do so. Moreover, IE1-72 binding to the grp78 promoter in infected cells accompanied the recruitment of TATA box-binding protein-associated factor 1 (TAF1), a histone acetyltransferase, and the increased level of acetylated histone H4, an indicator of active-state chromatin. These results provide evidence that HCMV IE1-72 activates grp78 gene expression through direct promoter binding and modulation of the local chromatin structure, indicating an active viral mechanism of cellular chaperone induction for viral growth.

Host-viral effects of chromatin assembly factor 1 interaction with HCMV IE2.

Chromatin assembly factor 1 (CAF1) consisting of p150, p60 and p48 is known to assemble histones onto newly synthesized DNA and thus maintain the chromatin structure. Here, we show that CAF1 expression was induced in human cytomegalovirus (HCMV)-infected cells, concomitantly with global chromatin decondensation. This apparent conflict was thought to result, in part, from CAF1 mislocalization to compartments of HCMV DNA synthesis through binding of its largest subunit p150 to viral immediate-early protein 2 (IE2). p150 interaction with p60 and IE2 facilitated HCMV DNA synthesis. The IE2Q548R mutation, previously reported to result in impaired HCMV growth with unknown mechanism, disrupted IE2/p150 and IE2/histones association in our study. Moreover, IE2 interaction with histones partly depends on p150, and the HCMV-induced chromatin decondensation was reduced in cells ectopically expressing the p150 mutant defective in IE2 binding. These results not only indicate that CAF1 was hijacked by IE2 to facilitate the replication of the HCMV genome, suggesting chromatin assembly plays an important role in herpesviral DNA synthesis, but also provide a model of the virus-induced chromatin instability through CAF1.

hNaa10p contributes to tumorigenesis by facilitating DNMT1-mediated tumor suppressor gene silencing.

Hypermethylation-mediated tumor suppressor gene silencing plays a crucial role in tumorigenesis. Understanding its underlying mechanism is essential for cancer treatment. Previous studies on human N-alpha-acetyltransferase 10, NatA catalytic subunit (hNaa10p; also known as human arrest-defective 1 [hARD1]), have generated conflicting results with regard to its role in tumorigenesis. Here we provide multiple lines of evidence indicating that it is oncogenic. We have shown that hNaa10p overexpression correlated with poor survival of human lung cancer patients. In vitro, enforced expression of hNaa10p was sufficient to cause cellular transformation, and siRNA-mediated depletion of hNaa10p impaired cancer cell proliferation in colony assays and xenograft studies. The oncogenic potential of hNaa10p depended on its interaction with DNA methyltransferase 1 (DNMT1). Mechanistically, hNaa10p positively regulated DNMT1 enzymatic activity by facilitating its binding to DNA in vitro and its recruitment to promoters of tumor suppressor genes, such as E-cadherin, in vivo. Consistent with this, interaction between hNaa10p and DNMT1 was required for E-cadherin silencing through promoter CpG methylation, and E-cadherin repression contributed to the oncogenic effects of hNaa10p. Together, our data not only establish hNaa10p as an oncoprotein, but also reveal that it contributes to oncogenesis through modulation of DNMT1 function.

Attenuation by methyl mercury and mercuric sulfide of pentobarbital induced hypnotic tolerance in mice through inhibition of ATPase activities and nitric oxide production in cerebral cortex.

This study is aimed at exploring the possible mechanism of hypnosis-enhancing effect of HgS or cinnabar (a traditional Chinese medicine containing more than 95% HgS) in mice treated with pentobarbital. We also examined whether the effect of HgS is different from that of the well-known methyl mercury (MeHg). After a short period (7 days) of oral administration to mice, a nontoxic dose (0.1 g/kg) of HgS not only significantly enhanced pentobarbital-induced hypnosis but also attenuated tolerance induction; while a higher dose (1 g/kg) of HgS or cinnabar exerted an almost irreversible enhancing effect on pentobarbital-hypnosis similar to that of MeHg (2 mg/kg) tested, which was still effective even after 10 or 35 days cessation of administration. To study comparatively the effects of different mercury forms from oral administration of MeHg and HgS on membrane ATPase activities of experimental mice, analysis of the Hg content in the cerebral cortex revealed that correlated with the decrease of Na(+)/K(+)-ATPase and Ca(2+)-ATPase activities. Furthermore, NO levels of blood but not that of cerebral cortex were also decreased by mercuric compounds. Although pentobarbital alone enhanced cytochrome p450-2C9 in time dependent manner, all of mercurial compounds tested had no such effect. All of these findings indicated that the mercurial compounds including cinnabar, HgS and MeHg exert a long-lasting enhancing hypnotic activity without affecting pentobarbital metabolism, which provides evidence-based sedative effect of cinnabar used in Chinese traditional medicine for more than 2,000 years. The nontoxic HgS dosing (0.1 g/kg/day) for consecutive 7 days is perhaps useful for delaying or preventing pentobarbital-tolerance.