[Role of hyperglycemia-induced 5-hydroxytryptamine degradation of hepatic stellate cells in hepatic inflammation and fibrosis induced by type 2 diabetes mellitus].

OBJECTIVE: To explore the role of 5-hydroxytryptamine (5-HT) in type 2 diabetes mellitus (T2DM)-related hepatic inflammation and fibrosis. METHODS: Male C57BL/6J mice were used to establish T2DM model by high-fat diet feeding combined with intraperitoneal injection of streptozotocin. Then, the mice with hyperglycemia were still fed with high-fat diet for nine weeks, and treated with or without 5-HT2A receptor (5-HT2AR) antagonist sarpogrelate hydrochloride (SH) and 5-HT synthesis inhibitor carbidopa (CDP) (alone or in combination). To observe the role of 5-HT in the myofibroblastization of hepa-tic stellate cells (HSCs), human HSCs LX-2 were exposed to high glucose, and were treated with or without SH, CDP or monoamine oxidase A (MAO-A) inhibitor clorgiline (CGL). Hematoxylin & eosin and Masson staining were used to detect the pathological lesions of liver tissue section, immunohistochemistry and Western blot were used to analyze protein expression, biochemical indicators were measured by ELISA or enzyme kits, and levels of intracellular reactive oxygen species (ROS) were detected by fluorescent probe. RESULTS: There were up-regulated expressions of 5-HT2AR, 5-HT synthases and MAO-A, and elevated levels of 5-HT in the liver of the T2DM mice. In addition to reduction of the hepatic 5-HT levels and MAO-A expression, treatment with SH and CDP could effectively ameliorate liver lesions in the T2DM mice, both of which could ameliorate hepatic injury and steatosis, significantly inhibit the increase of hepatic ROS (H2O2) levels to alleviate oxidative stress, and markedly suppress the production of transforming growth factor ß1 (TGF-ß1) and the development of inflammation and fibrosis in liver. More importantly, there was a synergistic effect between SH and CDP. Studies on LX-2 cells showed that high glucose could induce up-regulation of 5-HT2AR, 5-HT synthases and MAO-A expression, increase intracellular 5-HT level, increase the production of ROS, and lead to myofibroblastization of LX-2, resulting in the increase of TGF-ß1 synthesis and production of inflammatory and fibrosis factors. The effects of high glucose could be significantly inhibited by 5-HT2AR antagonist SH or be markedly abolished by mitochondrial 5-HT degradation inhibitor CGL. In addition, SH significantly suppressed the up-regulation of 5-HT synthases and MAO-A induced by high glucose in LX-2. CONCLUSION: Hyperglycemia-induced myofibroblastization and TGF-ß1 production of HSCs, which leads to hepatic inflammation and fibrosis in T2DM mice, is probably due to the up-regulation of 5-HT2AR expression and increase of 5-HT synthesis and degradation, resulting in the increase of ROS production in mitochondria. Among them, 5-HT2AR is involved in the regulation of 5-HT synthases and MAO-A expression.

Correlation between AS1 gene expression and seed protein contents in different soybean (Glycine max [L.] Merr.) cultivars.

In higher plants, asparagine synthetase (AS) plays an important role in regulating the nitrogen sink-source relationship. We studied the expression of AS genes in five Chinese soybean cultivars exhibiting contrasting seed protein contents. We found that only the AS2 but not the AS1 gene was induced by dark treatment. On the other hand, the expression of AS1 in leaves (especially in trifoliate leaves of young seedlings) showed a positive correlation with seed protein contents in the soybean cultivars tested. Therefore, in spite of the fact that the principle transporting compounds in soybean plants for nitrogen acquired via symbiotic fixation are ureides, AS may still play an important role in the process of nitrogen assimilation.

Silencing an ACC oxidase gene affects the susceptible host response of Nicotiana benthamiana to infection by Colletotrichum orbiculare.

An 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase, NbACO1, was cloned from cDNA of Nicotiana benthamiana leaves infected with the hemibiotrophic fungal pathogen, Colletotrichum orbiculare. Expression of NbACO1 increased approximately 3-fold by 24 h after inoculation and then continued to increase reaching a maximum that was 6-folds greater than that in healthy plants by 96 h after inoculation. A portion of NbACO1 was cloned into a PVX vector for virus-induced gene silencing, and the silencing resulted in a reduction in its expression to 7-9% of that found in the controls for fungal-infected leaf tissue. Silencing of NbACO1 also resulted in significant reductions in transcript levels of genes encoding an ethylene responsive transcription factor and two glutathione S-transferases, but not for a basic pathogenesis-related protein gene, indicating that at least some genes associated with ethylene signaling were affected by the silencing treatment. Inoculated NbACO1-silenced plants developed more lesions more quickly as a result of an accelerated switch from the symptomless, biotrophic phase to the symptomatic necrotrophic phase of infection compared to inoculated control plants. This indicates that manipulation of ACC oxidase can affect the length of the biotrophic phase of infection in this interaction.

Rapid and quantitative detection of hepatitis A virus from green onion and strawberry rinses by use of real-time reverse transcription-PCR.

In this study, an immunomagnetic capture method and a real-time reverse transcription-PCR assay were used to quantify hepatitis A virus (HAV) in green onion and strawberry rinses. This combined protocol detected as low as 0.5 PFU HAV in produce rinses and concentrated HAV levels up to 20-fold.

Characterization and taxonomic placement of Rhizoctonia-like endophytes from orchid roots.

Twenty-one Rhizoctonia-like fungal strains were isolated from the roots of four terrestrial orchid species from various locations in Hong Kong. The cultural morphology, nuclear number of the hyphal cell, pore ultrastructure, and RAPD and CAPS analyses of rDNA fragments revealed that most of these isolates were associated with the genera Ceratorhiza and Epulorhiza. RAPD analysis showed the presence of genetic diversity between the isolates from different hosts and locations. The compatibility between a selection of these Ceratorhiza and Epulorhiza isolates and 14 orchid species was determined using a symbiotic germination method. The germination and development of three orchid species, Arundina chinensis, Spathoglottis pubescens, and Spiranthes hongkongensis, were strongly stimulated by the Epulorhiza isolates. Habenaria dentata was found to form symbionts successfully with a Ceratorhiza isolate.

ZAP-70 and SLP-76 regulate protein kinase C-theta and NF-kappa B activation in response to engagement of CD3 and CD28.

The transcription factor NF-kappaB is a critical regulator of T cell function that becomes strongly activated in response to coengagement of TCR and CD28. Although events immediately proximal to NF-kappaB activation are well understood, uncertainty remains over which upstream signaling pathways engaged by TCR and CD28 lead to NF-kappaB activation. By using Jurkat T cell lines that are deficient or replete for either the protein tyrosine kinase ZAP-70 or the cytosolic adapter molecule SLP-76, the role of these proteins in modulating NF-kappaB activation was examined. NF-kappaB was not activated in response to coengagement of TCR and CD28 in either the ZAP-70- or SLP-76-negative cells, whereas stimuli that bypass these receptors (PMA plus A23187, or TNF-alpha) activated NF-kappaB normally. Protein kinase C (PKC) theta activation, which is required for NF-kappaB activation, also was defective in these cells. Reexpression of ZAP-70 restored PKCtheta and NF-kappaB activation in response to TCR and CD28 coengagement. p95(vav) (Vav)-1 tyrosine phosphorylation was largely unperturbed in the ZAP-70-negative cells; however, receptor-stimulated SLP-76/Vav-1 coassociation was greatly reduced. Wild-type SLP-76 fully restored PKCtheta and NF-kappaB activation in the SLP-76-negative cells, whereas 3YF-SLP-76, which lacks the sites of tyrosine phosphorylation required for Vav-1 binding, only partially rescued signaling. These data illustrate the importance of the ZAP-70/SLP-76 signaling pathway in CD3/CD28-stimulated activation of PKC theta and NF-kappaB, and suggest that Vav-1 association with SLP-76 may be important in this pathway.