Dual engagement of 14-3-3 proteins controls signal relay from ASK2 to the ASK1 signalosome

Faithful and efficient transmission of biological signals through mitogen-activated protein kinase (MAPK) pathways requires engagement of highly regulated cellular machinery in response to diverse environmental cues. Here, we report a novel mechanism controlling signal relay between two MAP3Ks, apoptosis signal-regulating kinase (ASK) 1 and ASK2. We show that ASK2 specifically interacts with 14-3-3 proteins through phosphorylated S964. Although a 14-3-3-binding defective mutant of ASK1 (S967A) has no effect on the ASK2/14-3-3 interaction, both overexpression of the analogous ASK2 (S964A) mutant and knockdown of ASK2 dramatically reduced the amount of ASK1 complexed with 14-3-3. These data suggest a dominant role of ASK2 in 14-3-3 control of ASK1 function. Indeed, ASK2 S964A-induced dissociation of 14-3-3 from ASK1 correlated with enhanced phosphorylation of ASK1 at T838 and increased c-Jun N-terminal kinase phosphorylation, the two biological readouts of ASK1 activation. Our results suggest a model in which upstream signals couple ASK2 S964 phosphorylation to the ASK1 signalosome through dual engagement of 14-3-3.

Triterpenoid saponins from Rubus ellipticus var. obcordatus

Ten new triterpenoid saponins (1-10), named rubusides A-J, and 21 known saponins (11-31) were isolated from the roots of Rubus ellipticus var. obcordatus. The structures of 1-10 were established on the basis of spectroscopic analyses, mainly NMR and MS, and chemical degradations. The compounds demonstrated inhibitory activities against alpha-glucosidase with IC50 values in the range 0.65-3.09 mM.

Liver transplantation for hepatitis B virus-related hepatocellular carcinoma: one center's experience in China

BACKGROUND

Hepatocellular carcinoma (HCC) is the fifth most common and the third most deadly cancer worldwide, with more than half a million identified cases and about a similar number of subjects succumb to it each year. This study sought to evaluate our results of liver transplantation for HCC to identify prognostic factors.

METHODS

Between December 2001 and December 2006, 224 patients (205 men, 19 women; age range, 15-75 years) with HCC underwent orthotopic liver transplantation (OLT) at our center. All grafts were from deceased donors. There were 68 cases within Milan criteria (30.3%), 32 cases beyond Milan criteria but within UCSF (University of California, San Francisco) criteria (14.3%), and 124 cases beyond UCSF criteria (55.4%).

RESULTS

The overall 1-, 3-, and 5-year patient cumulative survival rates were 82.5%, 60.1%, and 51.5%, respectively. The survival rates were comparable between patients within Milan and UCSF criteria, but were significantly greater than that of patients beyond UCSF criteria. Multivariate analysis revealed alpha fetoprotein (AFP) >or= 800 microg/L, vascular invasion, and poor tumor differentiation to be independent prognostic factors.

CONCLUSION

OLT is a safe and effective treatment for hepatitis B virus-related HCC. Compared with Milan criteria, UCSF criteria successfully expanded the indication without deteriorating the prognosis significantly, while preoperative AFP >or= 800 microg/L, vascular invasion, and poor tumor differentiation indicated poor survival.

Full-genome nucleotide sequence and analysis of a Chinese swine hepatitis E virus isolate of genotype 4 identified in the Guangxi Zhuang autonomous region: evidence of zoonotic risk from swine to human in South China

BACKGROUND

Hepatitis E virus (HEV) is one of the leading causes of the enteric-transmitted acute hepatitis. Many studies have found high identities between human and animal HEV isolates using partial sequence comparison analysis.

AIMS

To determine and phylogenetically analyse the complete genome of the swGX40 isolate from the Guangxi Zhuang autonomous region.

METHODS

The overlapping fragments of HEV isolate swGX40 were amplified with reverse transcription-nested polymerase chain reaction (PCR) and the 5' and 3' ends of viral genome were amplified with rapid amplification of cDNA ends. The PCR products were cloned and sequenced. The sequence and phylogenetic analysis of swGX40 were performed.

RESULTS

The full genome of the swGX40 strain consisted of 7233 nucleotides, excluding the poly (A) tail of 36 residues. There are three open reading frames (ORFs), encoding 1705, 674 and 114 amino acids (aa) respectively. The full-genomic sequencing showed that the swGX40 strain shared similarity with all known HEV genotype 1, 2 and 3 isolates by 73.4-76.5% and with an identity of 83.1-91.2% among genotype 4 HEV isolates. The partial ORF2 sequencing (249 nt) showed that swGX40 shared a high nucleotide identity of 94 and 97% with the Chinese human strain LZ-105 and the Vietnamese human strain HE-JVN-1 respectively.

CONCLUSIONS

The swine isolate swGX40 was closely related to the human isolate LZ-105, both of which were collected from Liuzhou, the same district in the Guangxi Zhuang autonomous region. This molecular biological evidence strongly supported the zoonosis hypothesis of hepatitis E.

Effects of magnesium salt concentrations on B-DNA overstretching transition

In this study, we use optical tweezers to investigate the ionic effects of magnesium salt solutions on the overstretching transition of single B-DNA molecules. The experimental data are compared with those in sodium salt solutions. The overstretching transition force increases when the NaCl or MgCl(2) salt concentration increases. Magnesium cations have much stronger effects on the overstretching transition force than sodium cations. For both NaCl and MgCl(2) salt solutions, the overstretching transition force is linear with the natural logarithm of salt concentration, which confirms the theory proposed in previous paper. The modified ZZO model is applied to study the electrostatic contribution of magnesium salt solutions to the overstretching transition of single B-DNA molecules. The consistency between the experimental data and analytical results shows that the modified ZZO model can simulate the transition behavior of single B-DNA molecules in different NaCl and MgCl(2) salt solutions.

Lanostane-type triterpenoids from the roots of Kadsura coccinea

Seven new lanostane-type triterpenoids, seco-coccinic acids A-F (1- 6) and coccinilactone A (7), were isolated from the roots of Kadsura coccinea. Their structures were established on the basis of spectroscopic data analysis. The absolute configuration at C-24 of compound 5 was confirmed by the modified Mosher's method. The cell growth inhibitory effects of these compounds were determined in human leukemia HL-60 cells, and it was found that compounds 1, 2, 3, and 5 exhibited antiproliferative effects with GI 50 values ranging from 6.8 to 42.1 microM.

Structure and absolute configuration of clerodane diterpene glycosides and a rearranged cadinane sesquiterpene glycoside from the stems of Tinospora sinensis

Three new clerodane diterpene glycosides, tinosposinensides A-C ( 1- 3), and a new rearranged cadinane sesquiterpene glycoside, tinosinenside ( 4), were isolated from the stems of Tinospora sinensis. The structure including the relative configuration was elucidated on the basis of spectroscopic analysis. The absolute configuration was determined by application of the modified Mosher's method and chemical transformation. The inhibitory activities of the isolated compounds against alpha-glucosidase are also described.

New 4alpha-methyl steroids from a Chinese soft coral Nephthea sp

Three new 4alpha-methyl steroids, 4alpha-methyl-ergost-7,24(28)-diene-3beta-ol-23-one (1), 4alpha-methyl-ergost-8(14),24(28)-diene-3beta-ol-23-one (2), 4alpha-methyl-ergost-24(28)-en-3beta,11beta-diol-23-one (3), and two new polyoxygenated steroids, ergost-5,25-diene-3beta,24S,28-triol (4), ergost-5,24(28)-diene-3beta,23S-diol (5), along with one known steroid 24-methylencholesterol (6) were isolated from the soft coral Nephthea sp. Their structures including the relative configurations were elucidated by extensive 1D and 2D NMR spectra analysis. The absolute configurations of (4) and (5) were determined by the Mosher's method.

A new isoflavone glucoside from Astragalus membranaceus var. mongholicus

A new isoflavone glucoside (1) was isolated from the roots of Astragalus membranaceus var. mongholicus. Its structure was elucidated by spectroscopic methods.

The non-steroidal anti-inflammatory drug piroxicam blocks ligand binding to the formyl peptide receptor but not the formyl peptide receptor like 1

The anti-inflammatory drug piroxicam has been reported to affect the production of reactive oxygen species in phagocytes. This anti-inflammatory effect is thought to be mediated through inhibition of cyclooxygenase (COX), an enzyme important for prostaglandin synthesis. We have compared the effects of piroxicam on superoxide production mediated by two closely related G-protein coupled receptors expressed on neutrophils, the formyl peptide receptor (FPR) and the formyl peptide receptor like 1 (FPRL1). Neutrophils were stimulated with agonists that bind specifically to FPR (the peptide ligand N-formyl-Met-Leu-Phe, fMLF) or FPRL1 (the peptide ligand Trp-Lys-Tyr-Met-Val-L-Met-NH(2), WKYMVM) or both of these receptors (the peptide ligand Trp-Lys-Tyr-Met-Val-D-Met-NH(2), WKYMVm). Piroxicam reduced the neutrophil superoxide production induced by the FPR agonist but had no significant effect on the FPRL1 induced response. Neutrophil intracellular calcium changes induced by the agonist WKYMVm (that triggers both FPR and FPRL1) were only inhibited by piroxicam when the drug was combined with the FPRL1 specific antagonist, Trp-Arg-Trp-Trp-Trp-Trp (WRW(4)), and this was true also for the inhibition of superoxide anion release. Receptor-binding analysis showed that the fluorescently labelled FPR specific ligand N-formyl-Nle-Leu-Phe-Nle-Tyr-Lys (fNLFNYK), was competed for in a dose-dependent manner, by the FPR ligand fMLF and as well as by piroxicam. We show that piroxicam inhibits the neutrophil responses triggered through FPR, but not through FPRL1 and this inhibition is due to a reduced binding of the activating ligand to its cell surface receptor.

Multivisceral resections of gastrointestinal stromal tumors

20523

Background: Gastrointestinal stromal tumors (GISTs) with positive kit staining, although rare, are the most common mesenchymal neoplasms affecting the gastrointestinal tract. We present our experience in the treatment of disease involving adjacent organs with multivisceral resections. Methods: The clinicopathologic records of twenty-two patients with multivisceral resection, among 170 patients suffered from GISTs treated in our hospital from 1994 to 2005, were retrospectively reviewed. Nine primary tumors originated from the stomach, 4 from the small intestine, 6 from the colorectum, 1 from abdominal cavity, and 2 from the retroperitoneal area. Meanwhile complete follow-up records were available in 15 patients with median 5-year follow-up. Results: The patients included 9 men and 13 women, from 36 to 77 year old. The largest tumor diameter ranged from 2 to 20 cm. The types of multivisceral operation comprised splenectomy (n=8), coloectomy (n=6), nephrectomy (n=5), partial hepatectomy (n=1), duodenectomy (n=1), oophorectomy (n=1), pancreatectomy (n=1), and adrenalectomy (n=1). None of lymph node metastatsis was found in 7 patients with lymph node dissection with gastric GISTs (n=5) or small intestinal GISTs (n=2). The involved organs confirmed by the pathologic diagnosis included kidney (n=2), spleen (n=2), pancreas (n=2), mesentery (n=1), and omentum (n=1). There was no perioperative mortality in this series. Among follow up patients, 9 were alive and 5 were died from the tumor recurrence or metastasis. Among them, one person with gastrectomy, pancreatectomy, adrenalectomy is still alive under 2 year follow-up by imatinib mesylate therapy postoperatively. Conclusions: Complete surgical resection with a negative gross margin by en bloc resection of the involved organs remains the standard treatment for non-metastatic GISTs. Imatinib mesylate represents a major breakthrough in the treatment of advanced GISTs and is the first effective systemic therapy for the disease.

No significant financial relationships to disclose.

The prognostic analysis of gastrointestinal stromal tumor

20534

Objective: To investigate the prognostic factor of gastrointestinal stromal tumor. Methods: The clinicopathological data of 103 patients with gastrointestinal stromal tumors were analyzed restrospectively. Life table, kaplan-meier survival rate and cox regression model were used to evaluate the prognostic factors. Results: The 1 year ,3 years and 5 years total survival rate of these 103 gastrointestinal stromal tumors was 86.3%, 51.7%, 42.8%. Tumor size, mitotic rate, primary organ of tumor and radical surgical excision or not were analyzed respectively, the difference is statistical significance (P<0.05). No significiant difference between the group of sex, age, immunohistochemistry expression and multi-organ resection or not. Conclusion: Flechers’ classification is rational, scientific, simple and feasible. Radical surgical excision is the best therapy to the primary gastrointestinal stomal tumor.

No significant financial relationships to disclose.

Akt phosphorylation of zyxin mediates its interaction with acinus-S and prevents acinus-triggered chromatin condensation

Zyxin, a focal adhesion molecule, contains LIM domains and shuttles between the cytoplasm and the nucleus. Nuclear zyxin promotes cardiomyocyte survival, which is mediated by nuclear-activated Akt. However, the molecular mechanism of how zyxin antagonizes apoptosis remains elusive. Here, we report that zyxin binds to acinus-S, a nuclear speckle protein inducing apoptotic chromatin condensation after cleavage by caspases, and prevents its apoptotic action, which is regulated by Akt. Akt binds and phosphorylates zyxin on serine 142, leading to its association with acinus. Interestingly, 14-3-3gamma, but not zeta isoform selectively, triggers zyxin nuclear translocation, which is Akt phosphorylation dependent. Zyxin is also a substrate of caspases, but Akt phosphorylation is unable to prevent its apoptotic cleavage. Expression of zyxin S142D, a phosphorylation mimetic mutant, diminishes acinus proteolytic cleavage and chromatin condensation; by contrast, wild-type zyxin or unphosphorylated S142A mutant fails. Thus, Akt regulates zyxin/acinus complex formation in the nucleus, contributing to suppression of apoptosis.

Knowledge-based algorithms for chemical structure and property analysis

We have successfully developed 'rule-based' algorithms that efficiently perform sub- and exact-structure searching, as well as accurately describe the chemistry of small molecules. These algorithms use a simple and concise set of rules for information extraction from molecule files. This design is intended to reduce the computational time required for the process, while improving the accuracy in the tasks. The performances of these algorithms have been successfully validated with a wide range of small molecules. Our future goal is to combine these algorithms with our newly designed knowledge-based object database, such that their tasks can be automated with a high efficiency.

Significantly increased lifespan and improved behavioral performances by rAAV gene delivery in adult mucopolysaccharidosis IIIB mice

Mucopolysaccharidosis (MPS) IIIB is an inherited lysosomal storage disease, caused by the deficiency of alpha-N-acetylglucosaminidase (NaGlu), resulting in severe global neurological involvement with high mortality. One major hurdle in therapeutic development for MPS IIIB is the presence of the blood-brain barrier, which impedes the global central nervous system (CNS) delivery of therapeutic materials. In this study, we used a minimal invasive strategy, combining an intravenous (i.v.) and an intracisternal (i.c.) injection, following an i.v. infusion of mannitol, to complement the CNS delivery of adeno-associated viral (AAV) vector for treating MPS IIIB in young adult mice. This treatment resulted in a significantly prolonged lifespan of MPS IIIB mice (11.1-19.5 months), compared with that without treatment (7.9-11.3), and correlated with significantly improved behavioral performances, the restoration of functional NaGlu, and variable correction of lysosomal storage pathology in the CNS, as well as in different somatic tissues. This study demonstrated the great potential of combining i.v. and i.c. administration for improving rAAV CNS gene delivery and developing rAAV gene therapy for treating MPS IIIB in patients.

Pancreatic Lipase-Inhibiting Triterpenoid Saponins from Fruits of Acanthopanax senticosus

Sixteen triterpenoid saponins were isolated from the fruits of Acanthopanax senticosus, including a new compound, acanthopanaxoside E (1), which was established as 3-O-beta-D-glucuronopyranosyl echinocystic acid 28-O-beta-D-glucopyranoside on the basis of various spectroscopic analyses and chemical degradation. By using a pancreatic lipase-inhibiting assay system, the crude saponin fraction showed inhibitory activity on pancreatic lipase, which is a key enzyme in lipid digestion. Among the isolated compounds, silphioside F (2), copteroside B (3), hederagenin 3-O-beta-D-glucuronopyranoside 6'-O-methyl ester (4) and gypsogenin 3-O-beta-D-glucuronopyranoside (5) showed inhibitory activity toward pancreatic lipase with IC(50) values of 0.22, 0.25, 0.26 and 0.29 mM, respectively, and the free carboxylic acid groups in position 28 within their chemical structures were required for enhancement of pancreatic lipase inhibition.