Glycine N-methyltransferase deficiency in female mice impairs insulin signaling and promotes gluconeogenesis by modulating the PI3K/Akt pathway in the liver

Background

Glycine N-methyltransferase (GNMT) is abundantly expressed in the normal liver but is down-regulated in liver cancer tissues. GNMT knockout (Gnmt−/−) mice can spontaneously develop chronic hepatitis, fatty liver, and liver cancer. We previously demonstrated that hepatic GNMT is decreased in high-fat-diet-induced type 2 diabetes mellitus, but its contribution to metabolic syndrome is unclear. Here we show that GNMT modulates key aspects of metabolic syndrome in mice.

Methods

Eleven-week-old Gnmt−/− and wild-type (WT) mice with a C57BL/6 genetic background were used in this study. The metabolic defects of GNMT deficiency were measured by glucose and insulin tolerance tests, lipid homeostasis, gluconeogenesis, and insulin signaling.

Results

Gnmt−/− mice, especially females, exhibited glucose intolerance and insulin resistance. However, their body fat and lean mass, food and water intakes, and energy expenditure did not differ from those of WT mice. In addition, glucose-stimulated insulin secretion and insulin-stimulated glucagon secretion were normal in the serum and pancreatic islets of Gnmt−/− mice. Importantly, we found that GNMT deficiency increased lipogenesis and triglycerides in the liver. The elevated triglycerides disrupted the ability of insulin to induce Akt and S6 ribosomal protein phosphorylation, and then triggered insulin resistance and gluconeogenesis in female Gnmt−/− mice.

Conclusions

Our data indicate that hepatic GNMT regulates lipid and glucose homeostasis, and provide insight into the development of insulin resistance through modulating the PI3K/Akt pathway.

Electronic supplementary material

The online version of this article (doi:10.1186/s12929-016-0278-8) contains supplementary material, which is available to authorized users.

[Clinical analysis of efficacy and quality of life of segmental bowel resection for bowel endometriosis]

OBJECTIVE

To evaluate the efficacy and quality of life of segmental bowel resection for bowel endometriosis.

METHODS

Totally 62 symptomatic patients with bowel endometriosis undergoing segmental bowel resection were recruited. A visual analogue scale(VAS)and the 36-item short form health survey(SF-36)questionnaire were administered before and at least 1 year after surgery, respectively. Pregnancy rates were also recorded.

RESULTS

Sixty-two patients in total underwent follow-up ranging from 12 to 74 months. All patients complained of obvious pain symptoms, including dysmenorrhea, dyspareunia, pain on defecation and chronic pelvic pain. The relief of dysmenorrhea(2.9 ± 2.2 versus 7.5 ± 2.9), dyspareunia(0.7 ± 0.5 versus 4.3 ± 2.2)and pain on defecation(1.6 ± 0.7 versus 7.3 ± 1.9)after surgery was statistically significant(all P<0.01). The scores for all 8 domains of the SF-36 questionnaire were significant improved after segmental bowel resection(all P<0.01). The complication rate was 45%(28/62), including 18 cases of urinary retention, 4 rectovaginal fistulas, 2 cases of vaginal dehiscence, and 1 case each of thrombogenesis, pelvic abscess and general peritonitis. All of the patients with complications recovered well throughout follow-up. The postoperative pregnancy rate of the previous infertile patients was 6/10. Among the 6 gestational cases, 2 had labour, 2 underwent caesarean sections, one had a spontaneous natural abortion, and one underwent uterine curettage.

CONCLUSION

Segmental bowel resection could significantly relieve pain and improve quality of life for patients with bowel endometriosis.

Bortezomib inhibits Burkitt's lymphoma cell proliferation by downregulating sumoylated hnRNP K and c-Myc expression

Bortezomib (Velcal) was the first proteasome inhibitor to be approved by the US Food and Drug Administration to treat patients with relapsed/refractory multiple myelomas. Previous studies have demonstrated that bortezomib inhibits tumor cell proliferation and induces apoptosis by blocking the nuclear factor (NF)-κB pathway. However, the exact mechanism by which bortezomib induces cancer cell apoptosis is still not well understood. In this study, we found that bortezomib significantly inhibited cell proliferation in both human Burkitt's lymphoma CA46 and Daudi cells. Through proteomic analysis, we found that bortezomib treatment changed the expression of various proteins in distinct functional categories including unfolding protein response (UPS), RNA processing, protein targeting and biosynthesis, apoptosis, and signal transduction. Among the proteins with altered expression, hnRNP K, hnRNP H, Hsp90α, Grp78, and Hsp7C were common to both Daudi and CA46 cells. Interestingly, bortezomib treatment downregulated the expression of high-molecular-weight (HMw) hnRNP K and c-Myc but upregulated the expression of low-molecular-weight (LMw) hnRNP K. Moreover, cell proliferation was significantly correlated with high expression of HMw hnRNP K and c-Myc. HMw and LMw hnRNP K were identified as sumoylated and desumoylated hnRNP K, respectively. Using transient transfection, we found that sumoylated hnRNP K increased c-Myc expression at the translational level and contributed to cell proliferation, and that Lys422 of hnRNP K is the candidate sumoylated residue. Our results suggest that besides inhibiting the ubiquitin-proteasome pathway, bortezomib may inhibit cell proliferation by downregulating sumoylated hnRNP K and c-Myc expression in Burkitt's lymphoma cells.

An unusual ovarian neoplasm diagnosed in a patient with rupture of unicornuate uterus during pregnancy: a case report

Unicornuate uterus is a rare disease characterized with reduced fertility, and ovarian tumor diagnosed during pregnancy is uncommon as well. These two diseases have been reported separately. However, patient suffering from both diseases has never been reported before. The authors herein report a case of a 32-year-old Chinese woman presenting with a unicornuate uterus with no horn, who suffered from acute abdominal pain and intra-abdominal hemorrhage at 26 weeks gestation. Incidentally, a borderline ovarian tumor (BOT) and rupture of uterus were found during an urgent exploratory laparotomy. During the follow-up, ovarian tumor recurred in the first year after the operation. The authors suggest that BOT with micropapillary patterns should be paid much more attention to, other than only assessing the histological type. Furthermore, they also suggest that a slightly increased in serum CA-125 value should not be ignored.

15,16-Dihydrotanshinone I from the Functional Food Salvia miltiorrhiza Exhibits Anticancer Activity in Human HL-60 Leukemia Cells: in Vitro and in Vivo Studies

15,16-Dihydrotanshinone I (DHTS) is extracted from Salvia miltiorrhiza Bunge which is a functional food in Asia. In this study, we investigated the apoptotic effect of DHTS on the human acute myeloid leukemia (AML) type III HL-60 cell line. We found that treatment with 1.5 μg/mL DHTS increased proapoptotic Bax and Bad protein expressions and activated caspases-3, -8, and -9, thus leading to poly ADP ribose polymerase (PARP) cleavage and resulting in cell apoptosis. DHTS induced sustained c-Jun N-terminal kinase (JNK) phosphorylation and Fas ligand (FasL) expression. The anti-Fas blocking antibody reversed the DHTS-induced cell death, and the JNK-specific inhibitor, SP600125, inhibited DHTS-induced caspase-3, -8, -9, and PARP cleavage. In a xenograft nude mice model, 25 mg/kg DHTS showed a great effect in attenuating HL-60 tumor growth. Taken together, these results suggest that DHTS can induce HL-60 cell apoptosis in vitro and inhibit HL-60 cell growth in vivo; the underlying mechanisms might be mediated through activation of the JNK and FasL signal pathways.

Niemann-Pick type C2 protein regulates liver cancer progression via modulating ERK1/2 pathway: Clinicopathological correlations and therapeutical implications

Primary hepatocellular carcinoma (HCC) is the fifth most common malignancy worldwide and the third leading cause of cancer-related death. It is important to identify new targets for early diagnosis and treatment of HCC. Niemann-Pick type C2 (NPC2) plays an important role in the regulation of intracellular cholesterol homeostasis via direct binding with free cholesterol. However, little is known about the significance of NPC2 in HCC tumorigenesis. In this study, we showed that NPC2 is abundantly expressed in normal liver, but is downregulated in human HCC tissues. The patients with NPC2 downregulation expressed much higher α-fetoprotein, multiple tumor type, vascular invasion, later pathological stage and shorter survival rate. Knockdown NPC2 in liver cancer cell lines promote cell proliferation, migration and xenograft tumorigenesis. In contrast, NPC2 overexpression inhibits HuH7 promoted tumor growth. Furthermore, administration of hepatotropic adeno-associated virus 8 (AAV8) delivered NPC2 decreased the inflammatory infiltration, the expression of two early HCC markers-glypican 3 and survivin and suppressed the spontaneous HCC development in mice. To identify the NPC2-dependent mechanism, we emphasized on the status of MAPK/ERK signaling. MEK1/2 inhibitor treatment demonstrated that the expression of NPC2 affected the activation of ERK1/2 but not MEK1/2. In addition, cholesterol trafficking inhibitor treatment did not alter the cell proliferation and the activation of MEK/ERK. In conclusion, our study demonstrates that NPC2 may play an important role in negatively regulate cell proliferation and ERK1/2 activation that were independent of cholesterol accumulation. AAV-NPC2 may thus represent a new treatment strategy for liver cancer.

Involvement of cysteine-rich protein 61 in the epidermal growth factor-induced migration of human anaplastic thyroid cancer cells

Anaplastic thyroid cancer (ATC) is among the most aggressive types of malignant cancer. Epidermal growth factor (EGF) plays a crucial role in the pathogenesis of ATC, and patients with thyroid carcinoma typically exhibit increased cysteine-rich protein 61 (Cyr61). In this study, we found that EGF treatment induced cell migration, stress fiber formation, Cyr61 mRNA and protein expressions, and Cyr61 protein secretion in ATC cells. The recombinant Cyr61 protein significantly induced cell migration; however, inhibition of Cyr61 activity by a Cyr61-specific antibody abrogated EGF-induced cell migration. EGF treatment also affected epithelial-to-mesenchymal transition (EMT)-related marker protein expression, as evidenced by an increase in vimentin and a decrease in E-cadherin expression. Inhibition of Cyr61 expression by Cyr61 siRNA decreased cell migration and reversed the EMT-related marker protein expression. EGF treatment increased the phosphorylation of the extracellular signal-regulated kinase (ERK) and cAMP response element-binding protein (CREB), and finally activated Cyr61 promoter plasmid activity. Our results suggest that Cyr61 is induced by EGF through the ERK/CREB signal pathway and that it plays a crucial role in the migration and invasion of ATC cells; moreover, Cyr61 might be a therapeutic target for metastatic ATC.

N-hydroxycinnamide derivatives of osthole ameliorate hyperglycemia through activation of AMPK and p38 MAPK

Our previous studies found that osthole markedly reduced blood glucose levels in both db/db and ob/ob mice. To improve the antidiabetic activity of osthole, a series of N-hydroxycinnamide derivatives of osthole were synthesized, and their hypoglycemia activities were examined in vitro and in vivo. Both N-hydroxycinnamide derivatives of osthole, OHC-4p and OHC-2m, had the greatest potential for activating AMPK and increasing glucose uptake by L6 skeletal muscle cells. In addition, OHC-4p and OHC-2m time- and dose-dependently increased phosphorylation levels of AMPK and p38 MAPK. The AMPK inhibitor, compound C, and the p38 MAPK inhibitor, SB203580, significantly reversed activation of AMPK and p38 MAPK, respectively, in OHC-4p- and OHC-2m-treated cells. Compound C and SB203580 also inhibited glucose uptake induced by OHC-4p and OHC-2m. Next, we found that OHC-4p and OHC-2m significantly increased glucose transporter 4 (GLUT4) translocation to plasma membranes and counteracted hyperglycemia in mice with streptozotocin-induced diabetes. These results suggest that activation of AMPK and p38 MAPK by OHC-4p and OHC-2m is associated with increased glucose uptake and GLUT4 translocation and subsequently led to amelioration of hyperglycemia. Therefore, OHC-4p and OHC-2m might have potential as antidiabetic agents for treating type 2 diabetes. Our previous studies found that osthole markedly reduced blood glucose levels in both db/db and ob/ob mice. To improve the antidiabetic activity of osthole, a series of N-hydroxycinnamide derivatives of osthole were synthesized, and their hypoglycemia activities were examined in vitro and in vivo. Both N-hydroxycinnamide derivatives of osthole, OHC-4p and OHC-2m, had the greatest potential for activating AMPK and increasing glucose uptake by L6 skeletal muscle cells. In addition, OHC-4p and OHC-2m time- and dose-dependently increased phosphorylation levels of AMPK and p38 MAPK. The AMPK inhibitor, compound C, and the p38 MAPK inhibitor, SB203580, significantly reversed activation of AMPK and p38 MAPK, respectively, in OHC-4p- and OHC-2m-treated cells. Compound C and SB203580 also inhibited glucose uptake induced by OHC-4p and OHC-2m. Next, we found that OHC-4p and OHC-2m significantly increased glucose transporter 4 (GLUT4) translocation to plasma membranes and counteracted hyperglycemia in mice with streptozotocin-induced diabetes. These results suggest that activation of AMPK and p38 MAPK by OHC-4p and OHC-2m is associated with increased glucose uptake and GLUT4 translocation and subsequently led to amelioration of hyperglycemia. Therefore, OHC-4p and OHC-2m might have potential as antidiabetic agents for treating type 2 diabetes.

Combined treatment with troglitazone and lovastatin inhibited epidermal growth factor-induced migration through the downregulation of cysteine-rich protein 61 in human anaplastic thyroid cancer cells

Our previous studies have demonstrated that epidermal growth factor (EGF) can induce cell migration through the induction of cysteine-rich protein 61 (Cyr61) in human anaplastic thyroid cancer (ATC) cells. The aim of the present study was to determine the inhibitory effects of combined treatment with the peroxisome proliferator-activated receptor-γ (PPARγ) ligand troglitazone and the cholesterol-lowering drug lovastatin at clinically achievable concentrations on ATC cell migration. Combined treatment with 5 μM troglitazone and 1 μM lovastatin exhibited no cytotoxicity but significantly inhibited EGF-induced migration, as determined using wound healing and Boyden chamber assays. Cotreatment with troglitazone and lovastatin altered the epithelial-to-mesenchymal-transition (EMT) -related marker gene expression of the cells; specifically, E-cadherin expression increased and vimentin expression decreased. In addition, cotreatment reduced the number of filopodia, which are believed to be involved in migration, and significantly inhibited EGF-induced Cyr61 mRNA and protein expression as well as Cyr61 secretion. Moreover, the phosphorylation levels of 2 crucial signal molecules for EGF-induced Cyr61 expression, the cAMP response element-binding protein (CREB) and extracellular signal-regulated kinase (ERK), were decreased in cells cotreated with troglitazone and lovastatin. Performing a transient transfection assay revealed that the combined treatment significantly suppressed Cyr61 promoter activity. These results suggest that combined treatment with low doses of troglitazone and lovastatin effectively inhibits ATC cell migration and may serve as a novel therapeutic strategy for metastatic ATC.

Correction: Surface-enhanced Raman scattering on a silver film-modified Au nanoparticle-decorated SiO2 mask array

Correction for ‘Surface-enhanced Raman scattering on a silver film-modified Au nanoparticle-decorated SiO₂ mask array’ by Chi-Ching Chang et al., RSC Adv., 2015, 5, 66096–66103.

Surface-enhanced Raman scattering on a silver film-modified Au nanoparticle-decorated SiO2 mask array

SERS of R6G absorbed on this developed array exhibits a higher intensity by ca. 30-fold, as compared with that of R6G absorbed on the Au NP-based array without the modification of Ag films.

Enterovirus-71 virus-like particles induce the activation and maturation of human monocyte-derived dendritic cells through TLR4 signaling

Enterovirus 71 (EV71) causes seasonal epidemics of hand-foot-and-mouth disease and has a high mortality rate among young children. We recently demonstrated potent induction of the humoral and cell-mediated immune response in monkeys immunized with EV71 virus-like particles (VLPs), with a morphology resembling that of infectious EV71 virions but not containing a viral genome, which could potentially be safe as a vaccine for EV71. To elucidate the mechanisms through which EV71 VLPs induce cell-mediated immunity, we studied the immunomodulatory effects of EV71 VLPs on human monocyte-derived dendritic cells (DCs), which bind to and incorporate EV71 VLPs. DC treatment with EV71 VLPs enhanced the expression of CD80, CD86, CD83, CD40, CD54, and HLA-DR on the cell surface; increased the production of interleukin (IL)-12 p40, IL-12 p70, and IL-10 by DCs; and suppressed the capacity of DCs for endocytosis. Treatment with EV71 VLPs also enhanced the ability of DCs to stimulate naïve T cells and induced secretion of interferon (IFN)-γ by T cells and Th1 cell responses. Neutralization with antibodies against Toll-like receptor (TLR) 4 suppressed the capacity of EV71 VLPs to induce the production of IL-12 p40, IL-12 p70, and IL-10 by DCs and inhibited EV71 VLPs binding to DCs. Our study findings clarified the important role for TLR4 signaling in DCs in response to EV71 VLPs and showed that EV71 VLPs induced inhibitor of kappaB alpha (IκBα) degradation and nuclear factor of kappaB (NF-κB) activation.

MCPIP1 suppresses hepatitis C virus replication and negatively regulates virus-induced proinflammatory cytokine responses

Human MCP-1-induced protein 1 (MCPIP1, also known as ZC3H12A and Regnase-1) plays important roles in negatively regulating the cellular inflammatory response. Recently, we found that as an RNase, MCPIP1 has broad-spectrum antiviral effects by targeting viral RNA. In this study, we demonstrated that MCPIP1 expression was induced by hepatitis C virus (HCV) infection in Huh7.5 hepatoma cells. MCPIP1 expression was higher in liver tissue from patients with chronic HCV infection compared with those without chronic HCV infection. Knockdown of MCPIP1 increased HCV replication and HCV-mediated expression of proinflammatory cytokines, such as TNF-α, IL-6, and MCP-1. However, overexpression of MCPIP1 significantly inhibited HCV replication and HCV-mediated expression of proinflammatory cytokines. Various mutants of functional domains of MCPIP1 showed disruption of the RNA binding and oligomerization abilities, as well as RNase activity, but not deubiquitinase activity, which impaired the inhibitory activity against HCV replication. On immunocytochemistry, MCPIP1 colocalized with HCV RNA. Use of a replication-defective HCV John Cunningham 1/AAG mutant and in vitro RNA cleavage assay demonstrated that MCPIP1 could directly degrade HCV RNA. MCPIP1 may suppress HCV replication and HCV-mediated proinflammatory responses with infection, which might contribute to the regulation of host defense against the infection and virus-induced inflammation.

Antihypertensive Activities of a Solid-State Culture ofTaiwanofungus camphoratus(Chang-Chih) in Spontaneously Hypertensive Rats

Wild and solid-state cultures (SSC) of Taiwanofungus camphoratus (aka Antrodia camphorata and Chang-chih [CC]) were sequentially extracted with cold water, methanol, and hot water to get cold-water-soluble (CWS), methanol-soluble (MS), and hot-water-soluble (HWS) extracts, respectively. Only the MS extract exhibited angiotensin-converting enzyme (ACE) inhibitory activities. The antihypertensive effects of the MS extract (10 mg/kg BW) were measured in spontaneously hypertensive rats (SHR) and Wistar Kyoto (WKY) rats. MS extract of the SSC type was able to effectively lower the systolic blood pressure (SBP) and diastolic blood pressure (DBP) of SHR, but not of WKY rats, the results being significantly different from those for distilled water only (the blank). However, wild CC and its MS extract were not as effective as the SSC type in reducing SHR blood pressure and had no effect on WKY rats. SSC-type CC might be developed into a health food with the ability to regulate blood pressure.

15,16-Dihydrotanshinone I-induced apoptosis in human colorectal cancer cells: involvement of ATF3

15,16-Dihydrotanshinone I (DHTS) is a component of the traditional Chinese medicinal plant Salvia miltiorrhiza Bunge. In this study, DHTS at as low as 2.5 μg/ml concentration significantly inhibited proliferation of human benign (SW480) and malignant (SW620) colorectal cancer cells, as shown by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-diphenytetrazoliumromide (MTT) and flow cytometric analysis. Activating transcription factor (ATF)-3, a basic leucine zipper-type transcription factor, was found to be predominantly up-regulated in DHTS-treated SW480 and SW620 cells. The up-regulation of ATF3 was blocked by a c-JUN N-terminal kinase (JNK) or p38 inhibitor. Overexpression of ATF3 resulted in a significant augmentation of DHTS-induced apoptosis of SW480 cells, but resistance to DHTS-induced apoptosis of SW620 cells. These results suggest that DHTS has a strong therapeutic or preventive potential against cancer. In addition, ATF3 has a dual role in DHTS-induced apoptosis, depending on the degree of malignancy of colorectal cancer.

Cytotoxicity of (-)-vitisin B in human leukemia cells

Vitis thunbergii var. taiwaniana (VTT) is an indigenous Taiwanese wild grape and is used as a folk medicine in Taiwan. VTT is rich in polyphenols, especially quercetin and resveratrol derivatives, which were demonstrated to exhibit inhibitory activities against carcinogenesis and prevent some neurodegenerative diseases. (-)-Vitisin B is one of the resveratrol tetramers extracted from VTT. In this study, we investigated the mechanisms of (-)-vitisin B on the induction of apoptosis in human HL-60 promyelocytic leukemia cells. First, (-)-vitisin B significantly inhibited cell proliferation through inducing cell apoptosis. This effect appeared to occur in a time- and dose-dependent manner. Cell-cycle distribution was also examined, and we found that (-)-vitisin B significantly induced a sub-G1 population in a dose-dependent manner. In addition, (-)-vitisin B exhibited stronger inhibitory effects on cell proliferation than resveratrol. Second, (-)-vitisin B dose dependently induced apoptosis-related protein expressions, such as the cleavage form of caspase-3, caspase-8, caspase-9, poly(ADP ribose) polymerase, and the proapoptotic Bax protein. Third, (-)-vitisin B treatment also resulted in increases in c-Jun N-terminal kinase (JNK) phosphorylation and Fas ligand (FasL) expression. Moreover, the (-)-vitisin B-induced FasL expression and caspase-3 activation could be reversed by a JNK inhibitor. These results suggest that (-)-vitisin B-induced apoptosis of leukemia cells might be mediated through activation of JNK and Fas death-signal transduction.

An in vitro hyperbaric oxygen system for evaluation of free radical damage and protection by catechins on hemorheological parameters

Free radicals play a critical role in causing hemorheologic abnormality which is highly correlated with cardiovascular disease and stroke. In this study, we established an in vitro model to evaluate the influence of free radical attacks on hemorheological parameters. A well-sealed chamber with hyperbaric oxygen was used to simulate an environment of free radical attacks. Hemorheological parameters, including whole blood viscosity, erythrocyte membrane lipid peroxidation, and erythrocyte deformability, were investigated. We then used the in vitro model to evaluate the anti-free radical effects of some well-known catechin antioxidants, such as epigallocatechin gallate (EGCG), (-)-epicatechin 3-gallate (ECG), and (-)-epigallocatechin (EGC) on abnormal hemorheological parameters induced by hyperbaric oxygen. The results show that an increase in oxygen partial pressure (1.0, 1.5, 2.0 and 2.5 atm) and exposure time (4, 8, 12 and 16 h) resulted in elevated free radical formation and viscosity of whole blood, enhanced lipid peroxidation in erythrocyte membranes, but decreased erythrocyte deformability. In addition, EGCG, ECG, and EGC (0.1, 0.5 and 1.0 μM) effectively ameliorated hemorheologic abnormality and enhanced erythrocyte deformability. Therefore, this study has provided an in vitro hyperbaric oxygen model to rapidly screen or assess the efficacy of functional foods and drugs in the prevention or improvement of hemorheologic abnormality.

Association between multiple sclerosis and erectile dysfunction: a nationwide case-control study

BACKGROUND

Multiple sclerosis (MS) commonly affects young adults who may be sexually active, with sexual dysfunction being a significant, but often underestimated, symptom of MS. However, no large-scaled study has investigated the association between erectile dysfunction (ED) and MS in an Asian population to date.

OBJECTIVE

The objective of this study is to estimate the association between ED and a prior diagnosis of MS using a population-based dataset with a case-control design in Taiwan.

METHODS

The data were sourced from National Health Insurance Research Database. We identified 38,139 patients with ED as cases and randomly selected 262,848 subjects as controls. We then used conditional logistic regression to compute the odds ratio for having previously received a diagnosis of MS between cases and controls.

RESULTS

The prevalence of prior MS was 0.037% and 0.015% for cases and controls, respectively (P < 0.001). Conditional logistic regression analysis revealed that cases were 2.23 times (95% confidence interval = 1.15-4.32) more likely to have been previously diagnosed with MS than controls after adjusting for monthly income, geographic location, hypertension, diabetes, coronary heart disease, hyperlipidemia, obesity, and alcohol abuse/alcohol dependence syndromes.

CONCLUSIONS

This study revealed an association between ED and prior MS even after adjusting for potential confounders.

Incorporation of exudates of human platelet-rich fibrin gel in biodegradable fibrin scaffolds for tissue engineering of cartilage

The goal of this study was to assess the incorporation of exudates of human platelet-rich fibrin (hPRF) that is abundant in platelet cytokines and growth factors into biodegradable fibrin (FB) scaffolds as a regeneration matrix for promoting chondrocyte proliferation and re-differentiation. hPRF was obtained from human blood by centrifugation without an anticoagulant, and the exudate of hPRF was collected and mixed with bovine fibrinogen, and then thrombin was added to form the FB scaffold. Proliferation and differentiation of human primary chondrocytes and a human chondrosarcoma cell line, the SW-1353, embedded in the three-dimensional (3D) scaffolds and on the two-dimensional (2D) surface of the FB scaffolds so produced were evaluated in comparison with an agarose (AG) scaffold serving as the control. Results demonstrated that the amounts of these cytokines and growth factors in hPRF exudates were higher than those in the blood-derived products except for TGF-β1. Chondrocytes and SW1353 cells on the 2D and 3D FB scaffolds with the addition of the exudates of PRF exhibited more-available proliferation and differentiation than cells on 2D and 3D FB and AG scaffolds. It was concluded that FB scaffolds can provide an appropriate environment for chondrocyte proliferation and re-differentiation, and it could be improved by adding exudates of hPRF. These 3D scaffolds have great promise for cartilage tissue engineering.

Osthole enhances glucose uptake through activation of AMP-activated protein kinase in skeletal muscle cells

AMP-activated protein kinase (AMPK) is an energy sensor that regulates cellular metabolism. Activation of AMPK in skeletal muscles, the liver, and adipose tissues results in a favorable metabolic milieu for preventing and treating type 2 diabetes, i.e., decreased levels of circulating glucose, plasma lipids, and ectopic fat accumulation and enhanced insulin sensitivity. Osthole was extracted from a Chinese herbal medicine, and we found that it had glucose lowering activity in our previous study. However, the detailed glucose lowering mechanisms of osthole are still unclear. In this study, we used skeletal muscle cells to examine the underlying molecular mechanisms of osthole's glucose lowering activity. A Western blot analysis revealed that osthole significantly induced phosphorylation of AMPK and acetyl-CoA carboxylase (ACC). Next, we found that osthole significantly increased the level of translocation of glucose transporter 4 (GLUT4) to plasma membranes and glucose uptake in a dose-dependent manner. Osthole-induced glucose uptake was reversed by treatment with Compound C, an AMPK inhibitor, suggesting that osthole-induced glucose uptake was mediated in an AMPK-dependent manner. The increase in the AMP:ATP ratio was involved in osthole's activation of AMPK. Finally, we found that osthole counteracted hyperglycemia in mice with streptozotocin-induced diabetes. These results suggest that the increase in the AMP:ATP ratio by osthole triggered activation of the AMPK signaling pathway and led to increases in plasma membrane GLUT4 content and glucose uptake level. Therefore, osthole might have potential as an antidiabetic agent for treating diabetes.

Lovastatin inhibits proliferation of anaplastic thyroid cancer cells through up-regulation of p27 by interfering with the Rho/ROCK-mediated pathway

Previously, we demonstrated that lovastatin, a HMG-CoA reductase inhibitor, induced apoptosis, differentiation, and inhibition of invasiveness of human anaplastic thyroid carcinoma cells (ATCs). Here, we further examined the effect of lovastatin on the growth of ARO cells. Lovastatin (0-20μM) concentration-dependently decreased cell number in cultured ATC and arrested the cell at the G0/G1 phase of the cell cycle. Western blot analysis revealed that lovastatin caused an increase of the protein level of p27 and cyclin-dependent kinase (CDK)4 and a decrease of the protein level of cyclin A2, cyclin D3, and phosphorylated Rb (pRb), but did not significantly change the protein levels of p21, cyclins D1 and E, and CDK2, in ARO cells. The formation of the CDK2-p27 complex was increased and the CDK2 activity was decreased in the lovastatin-treated ARO cells. Pretreatment of ARO cells with a p27, but not p21, antisense oligonucleotide prevented the lovastatin-induced G0/G1 arrest in ARO cells. The lovastatin-induced growth inhibition and translocation of RhoA and Rac1 in ARO cells were completely prevented by mevalonate and partially by geranylgeranyl pyrophosphate. Treatment of ARO cells with Y27632, an inhibitor of Rho-associated kinase, abolished the GGPP-mediated prevention of lovastatin-induced anti-proliferation and up-regulation and prolonged degradation of p27. Taken together, these data suggest that lovastatin treatment caused a reduction of Rho geranylgeranylation, which in turn increased the expression and stability of p27, and then inhibited ARO cell proliferation. These data suggest that lovastatin merits further investigation as multipotent therapy for treatment ATC.

Characterizations of chondrocyte attachment and proliferation on electrospun biodegradable scaffolds of PLLA and PBSA for use in cartilage tissue engineering

The influence of physical characteristics of electrospun three-dimensional (3D) fibrous scaffolds based on polybutylene succinate-co-adipate (PBSA) and poly l-lactic acid (PLLA) on the culture of primary human chondrocytes (PHCs) in terms of cell attachment, proliferation, and re-differentiation was investigated. Physical characteristics assessed for two polymers electrospun at two different delivery rates (PBSA-3, PBSA-16, PLLA-3, and PLLA-16) including average fiber diameter, average pore diameter, porosity, and contact angle. Results demonstrated that 3D fibrous scaffolds are better for PHCs' attachment than two-dimensional (2D) casting films made of the same polymeric materials. It was also found that 3D fibrous scaffolds are appropriate architecture for the proliferation of PHCs than 2D casting films and dependent upon the polymer used. Histological analysis revealed that a significant amount of PHC was found to be growing only within layers of PLLA fibrous scaffolds. The mitochondrial ribonucleic acid (mRNA) expression of both aggrecan and type II collagen by PHCs cultured in tissue culture polystyrene for 28 days decreased significantly. The mRNA expression of both aggrecan and type II collagen by PHCs cultured in PBSA scaffolds increased from 14 to 28 days, whereas only mRNA expression of aggrecan cultured in both PLLA scaffolds increased from 14 to 28 days.

β-Sitosterol inhibits cell cycle progression of rat aortic smooth muscle cells through increases of p21cip1 protein

Abnormal proliferation of vascular smooth muscle cells (VSMCs) plays a central role in the pathogenesis of atherosclerosis. β-Sitosterol, an important phytosterol found in plant food, is known to exert antiatherosclerosis activity. However, the molecular mechanisms underlying β-sitosterol-induced antiproliferation of VSMCs were still not clear. This study demonstrated that β-sitosterol (1-20 μM) concentration-dependently inhibited proliferation of rat aortic smooth muscle cells (RASMCs) without cytotoxic effect. Flow cytometric analysis revealed that β-sitosterol arrested cell cycle progression through down-regulation of cyclin E and cyclin-dependent kinase (CDK)2 and up-regulation of p21cip1. In the β-sitosterol-treated RASMCs, the formation of the CDK2-p21cip1 complex was increased and the assayable CDK2 activity was decreased. Knockdown of the expression of p21cip1 gene prevented β-sitosterol-induced cell cycle arrest in RASMCs. In conclusion, β-sitosterol inhibited VSMC proliferation by increasing the levels of p21cip1 protein, which in turn inhibited the CDK2 activity, and finally interrupted the progress of the cell cycle.