Infiltrating Foxp3(+) regulatory T cells from spontaneously tolerant kidney allografts demonstrate donor-specific tolerance

Foxp3(+) regulatory T cells (Tregs) have an essential role in immune and allograft tolerance. However, in both kidney and liver transplantation in humans, FOXP3(+) Tregs have been associated with clinical rejection. Therefore, the role and function of graft infiltrating Tregs have been of great interest. In the studies outlined, we demonstrated that Foxp3(+) Tregs were expanded in tolerant kidney allografts and in draining lymph nodes in the DBA/2 (H-2(d) ) to C57BL/6 (H-2(b) ) mouse spontaneous kidney allograft tolerance model. Kidney allograft tolerance was abrogated after deletion of Foxp3(+) Tregs in DEpletion of REGulatory T cells (DEREG) mice. Kidney allograft infiltrating Foxp3(+) Tregs (K-Tregs) expressed elevated levels of TGF-β, IL-10, interferon gamma (IFN-γ), the transcriptional repressor B lymphocyte-induced maturation protein-1 (Blimp-1) and chemokine receptor 3 (Cxcr3). These K-Tregs had the capacity to transfer dominant tolerance and demonstrate donor alloantigen-specific tolerance to skin allografts. This study demonstrated the crucial role, potency and specificity of graft infiltrating Foxp3(+) Tregs in the maintenance of spontaneously induced kidney allograft tolerance.

Exogenous nitric oxide negatively regulates the S-nitrosylation p38 mitogen-activated protein kinase activation during cerebral ischaemia and reperfusion

AIMS

A number of studies have suggested that nitric oxide (NO) plays an important role in the reactive phosphorylation of p38MAPKα (p38). However, whether S-nitrosylation of p38 is activated by NO and the details remain unclear. The aim of the present work was to assess the activation of p38, the S-nitrosylation site and the p38 signalling pathway in rat hippocampus and in HEK293 cell induced by exogenous NO.

METHODS

Primary hippocampal cultures, HEK293 cells and rat model of cerebral ischaemia/reperfusion (brain ischaemia was induced by four-vessel occlusion procedure) were used in this study. Biotin-switch method and immunoblotting were performed to study the S-nitrosylation and phosphorylation of p38, and neuronal loss was observed by histology.

RESULTS

Endogenous NO increased p38 phosphorylation and S-nitrosylation, and the activation of p38 was dependent on the S-nitrosylation of Cys-211, which was critical for the NO-mediated activation of p38. The exogenous NO donor sodium nitroprusside, S-nitrosoglutathione, 7-nitroindazole, the inhibitor of the neuronal nitric oxide synthase, inhibited the activation of p38 signal pathway induced by cerebral ischaemia/reperfusion and attenuated the damage in rat hippocampal neurones. Moreover, the N-methyl-D-aspartate receptor (NMDAR) is probably involved in the p38 activation process of S-nitrosylation and phosphorylation.

CONCLUSION

Endogenous NO induces the S-nitrosylation and phosphorylation of p38 and mediates p38 signalling pathway by NMDAR, and as exogenous NO inhibits this process and is neuroprotective in rat cerebral ischaemia/reperfusion, it may make a contribution to stroke therapy.

GluR6-FasL-Trx2 mediates denitrosylation and activation of procaspase-3 in cerebral ischemia/reperfusion in rats

Global cerebral ischemia/reperfusion (I/R) facilitates the activation of procaspase-3 and promotes apoptosis in hippocampus. But the mechanisms have remained uncharacterized. Protein S-nitrosylation and denitrosylation is an important reversible posttranslational modification, which is a common mechanism in signal transduction and affects numerous physiological and pathophysiological events. However, it is not known whether S-nitrosylation/denitrosylation modification of procaspase-3 serves as a component of apoptosis and cell death induced by cerebral I/R. Here we show that procaspase-3 is significantly denitrosylated and activated after I/R in rat hippocampus. NS102, a glutamate receptor 6 (GluR6) antagonist, can inhibit the denitrosylation of procaspase-3 and diminish the increased Fas ligand (FasL) and thioredoxin (Trx)-2 expression induced by cerebral I/R. Moreover, downregulation of FasL expression by antisense oligodeoxynucleotides inhibits the denitrosylation and activation of procaspase-3. Auranofin, a TrxR inhibitor or TrxR2 antisense oligodeoxynucleotide, has similar effects. In primary hippocampal cultures, Lentiviral-mediated knockdown of FasL and TrxR2 before the oxygen and glucose deprivation/reoxygenation further verifies that FasL and TrxR2 are involved in the denitrosylation of procaspase-3. In situ TUNEL staining and cresyl violet staining validate that inhibiting denitrosylation of procaspase-3 may exert neuroprotective effect on apoptosis and cell death induced by cerebral I/R in hippocampal CA1 pyramidal neurons. This is the first evidence that cerebral I/R mediates procaspase-3 denitrosylation and activation through GluR6-FasL-Trx2 pathway, which leads to neuronal apoptosis and cell death.

RKIP inhibits the malignant phenotypes of gastric cancer cells

Raf kinase inhibitor protein (RKIP) is first identified as an interacting partner of Raf-1. RKIP expression is low or absent in several established cell lines derived from metastatic breast cancer, prostate cancer and melanoma cells. However, the functional role of RKIP in gastric cancer remains unclear. In this study, we employed human gastric cancer cell line SGC7901 as a model to reconstitute RKIP expression in gastric cancer cells. The growth curve and soft agar assay showed that RKIP inhibited the growth and clonogenicity of SGC7901 cells. Flow cytometry analysis showed that RKIP inhibited the cell cycle progression and induced the apoptosis of SGC7901 cells. Wound healing and transwell invasion assay showed that RKIP inhibited the migration and invasion of SGC7901 cells. Furthermore, we observed that RKIP inhibited the growth of SMGC7901 cells in xenografts in nude mice. Taken together, our in vitro and in vivo data demonstrate that RKIP modulates the proliferation, apoptosis, migration, invasion and tumorigenicity of SGC7901 cells. These results reveal the tumor suppressor role of RKIP in gastric cancer and suggest that RKIP may be new therapeutic target for gastric cancer.

Endogenous nitric oxide induces activation of apoptosis signal-regulating kinase 1 via S-nitrosylation in rat hippocampus during cerebral ischemia-reperfusion

Apoptosis signal-regulating kinase 1 (ASK1) is a general mediator of cell death in response to a variety of stimuli, including reactive oxygen species, tumor necrosis factor α, lipopolysaccharide, endoplasmic reticulum stress, calcium influx and ischemia. Here we reported ASK1 was activated by nitric oxide (NO) through S-nitrosylation during cerebral ischemia-reperfusion. The reagents that abrogate neuronal nitric oxide synthase (nNOS) activity such as nNOS inhibitor 7NI and N-methyl-D-aspartate receptor antagonist MK801 prevented ASK1 activation via decreasing ASK1 S-nitrosylation. In HEK293 cells, over-expressed ASK1 could be S-nitrosylated by both exogenous and endogenous NO and Cys869 was identified as the site of ASK1 S-nitrosylation. S-nitrosylation increased the level of ASK1 phosphorylation at Thr845, which represents ASK1 activation. Our results further confirmed that S-nitrosylation led to the increment of ASK1 dimerization. S-nitrosylation of ASK1 also activated the downstream JNK signaling and JNK-mediated nucleic pathway. The exogenous NO (SNP and GSNO) reversed the effect of endogenous NO by suppressing S-nitrosylation of ASK1 and exerted neuroprotection during ischemia-reperfusion. These results suggest that inhibiting ASK1 S-nitrosylation may be a novel approach for stroke therapy.

Assessing genetic diversity of cotton cultivars using genomic and newly developed expressed sequence tag-derived microsatellite markers

Estimations of genetic diversity and of relationships between varieties are crucial for cotton breeding. The genetic diversity of 59 core cotton cultivars, most of which were collected from China's main cotton-growing areas, was analyzed based on genomic and newly developed expressed sequence tag-derived microsatellite markers, using total DNA extracted from fresh leaf tissue. Three hundred and two fragments were detected, of which 255 were polymorphic. The number of amplification products generated by each primer varied from 2 to 14, with a mean of 5.08 bands/primer. The polymorphism information content was 0.50 to 0.90, with a mean of 0.80. The genetic similarity coefficients were calculated and dendrograms were constructed by the unweighted pair group with arithmetic mean method; the resulting distance matrix gave a dendrogram with four main clusters. Some cultivars with similar pedigrees could be clustered. For example, Zhong206 and Shanmian4, both derived from Deltapine15, were clustered. The genetic similarity coefficient of the 59 core cultivars ranged from 0.53 to 0.99, with a mean of 0.72, indicating that there was a relatively high level of genetic variation.

Vitamin D: a novel therapeutic approach for keloid, an in vitro analysis

BACKGROUND

Vitamin D and its metabolites play an important role in calcium homeostasis, bone remodelling, hormone secretion, cell proliferation and differentiation. Recent studies also suggest a beneficial role of vitamin D in slowing the progression of tissue fibrosis. However, their effects on dermal fibrosis and keloids are unknown. Objectives  To investigate the effect of 1,25-dihydroxyvitamin D3 (1,25D) in the pathogenesis of tissue fibrosis by keloid fibroblasts (KFs).

METHODS

KFs were cultured and exposed to different concentrations of 1,25D in the presence or absence of transforming growth factor (TGF)-β1. KF phenotypes and protein production were analysed by real-time reverse transcriptase-polymerase chain reaction, Western blot, immunofluorescence and multiplex enzyme-linked immunosorbent assay techniques. Collagen synthesis was evaluated by measuring (3) H-proline incorporation. The effect of 1,25D on cell proliferation and viability was evaluated by Formazan assay, proliferating cell nuclear antigen expression and the colorimetric conversion of 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide.

RESULTS

We confirmed the presence of vitamin D receptors (VDRs) in cultured keloid fibroblasts. Fibroblasts transfected with a vitamin D response element reporter construct and exposed to the active vitamin D metabolite 1,25D showed increased promoter activity indicating VDR functionality in these cells. Incubation of KFs with 1,25D suppressed TGF-β1-induced collagen type I, fibronectin and α-smooth muscle actin expression. 1,25D also modulated plasminogen activator inhibitor-1 and matrix metalloproteinase-9 expression induced by TGF-β1. Interestingly, 1,25D induced hepatocyte growth factor mRNA expression and protein secretion in keloid fibroblasts.

CONCLUSIONS

This study highlights key mechanistic pathways through which vitamin D decreases fibrosis, and provides a rationale for studies to test vitamin D supplementation as a preventive and/or early treatment strategy for keloid and related fibrotic disorders.

Role of caveolin-1 in the pathogenesis of tissue fibrosis by keloid-derived fibroblasts in vitro

BACKGROUND

Recent studies have suggested that caveolin-1 (cav-1) plays an important role in the regulation of transforming growth factor (TGF)-β1 signalling and participates in the pathogenesis of tissue fibrosis. However, its effects on dermal fibrosis keloids are unknown.

OBJECTIVES

To investigate the effect of cav-1 in the pathogenesis of tissue fibrosis by keloid fibroblasts.

METHODS

Keloid fibroblasts were cultured and exposed to different concentrations of cav-1 cell-permeable peptides (cav-1p) in the presence of TGF-β1. Keloid fibroblast phenotypes and protein production were analysed by real-time reverse transcriptase-polymerase chain reaction, Western blot, and multiplex enzyme-linked immunosorbent assay techniques. The effect of cav-1p on cell viability was evaluated by MTT assay.

RESULTS

Cav-1 was markedly decreased in the keloid-derived fibroblasts. Moreover, cav-1p significantly reduced TGF-β receptor type I levels and Smad2/3 phosphorylation in response to added TGF-β1. Additionally, TGF-β1 decreased cav-1 expression in human skin fibroblasts. Cav-1 was able to suppress TGF-β1-induced extracellular matrix production in cultured keloid fibroblasts through regulation of the mitogen-activated protein kinase pathway.

CONCLUSIONS

Cav-1 appears to participate in the pathogenesis of tissue fibrosis in keloid. Restoration of cav-1 function by treatment with a cell-permeable peptide corresponding to the cav-1 scaffolding domain may be a novel therapeutic approach in keloid.

Inhibitory effects of retinoic acid on invasiveness of human thyroid carcinoma cell lines in vitro

BACKGROUND

The prognosis of patients with metastasized thyroid carcinoma is not optimistic, necessitating the search for new treatment options.

AIM

Beneficial effects of retinoic acid (RA) have been suggested in thyroid cancer differentiation and the present study was performed to investigate the anti-metastatic potential of RA in respect of important determinants of metastatic behavior in thyroid carcinoma, focusing on the role of invasion-associated proteins.

MATERIALS AND METHODS

Differentiated thyroid carcinoma cell lines FTC- 133 and XTC.UC1, and anaplastic thyroid cancer cell lines C643 and HTH74 were studied. All cell lines were cultured with alltrans- RA (ATRA) or the solvent ethanol. Invasion and adhesion potency in vitro was studied by transwell experiment and short-term adhesion assay. The involvement of invasion-associated proteins, urokinase type plasminogen activator (uPA), uPA receptor (uPAR), matrix metalloproteinase-2 (MMP-2) and E-cadherin, were investigated by semi-quantitative RT-PCR and Western blot.

RESULTS

In vitro invasion assay revealed that ATRA treatment could reduce the invasive potency in all the thyroid cancer cell lines, with the most significant effect in anaplastic cancer cells. Short-term adhesion assay suggested that ATRA increases cancer cell adhesion to extracellular matrix (ECM) in C643, HTH74 and XTC.UC1, probably through a transcriptional and translational regulation of some attachment molecules. RT-PCR andWestern blot both revealed diminished expression of uPAR in all four carcinoma cell lines. In C643 and HTH74 cell lines, the expression of uPA was reduced and the expression of E-cadherin was increased, whereas the MMP-2 expression was not significantly down-regulated in ATRA-treated group. In ATRA-treated FTC-133 and XTC.UC1 cell lines, MMP-2 expression was decreased, but no significant changes in uPA and E-cadherin expression were observed.

CONCLUSIONS

The present study demonstrates the influence of ATRA on both important determinants of metastatic behavior ("de-adhesion" and proteolysis) in thyroid carcinoma cell lines, especially in anaplastic cancer cells. These findings may add to the explanations for beneficial effects of RA in the treatment of metastatic thyroid carcinomas.

Neuroprotection of preconditioning against ischemic brain injury in rat hippocampus through inhibition of the assembly of GluR6-PSD95-mixed lineage kinase 3 signaling module via nuclear and non-nuclear pathways

Our previous studies showed that the assembly of the GluR6-PSD95-mixed lineage kinase 3 (MLK3) signaling module played an important role in rat ischemic brain injury. In this study, we aimed to elucidate whether ischemic preconditioning could downregulate the assembly of the GluR6-PSD95-MLK3 signaling module and suppress the activation of MLK3, MKK4/7, and c-Jun N-terminal kinase (JNK). As a result, ischemic preconditioning could not only inhibit the assembly of the GluR6-PSD95-MLK3 signaling module, diminish the phosphorylation of the transcription factor c-Jun, downregulate Fas ligand expression, attenuate the phosphorylation of 14-3-3 and Bcl-2 and the translocation of Bax to mitochondria, but also increase the release of cytochrome c and the activation of caspase-3. In contrast, both GluR6 antisense ODNs (oligodeoxynucleotides) and 6,7,8,9-tetrahydro-5-nitro-1 H-benz[g]indole-2,3-dione-3-oxime (NS102), an antagonist of GluR6 receptor, prevented the above effects of preconditioning, which shows that suppressing the expression of GluR6 or inhibiting GluR6 activity contributes negatively to preconditioning-induced ischemia tolerance. Taken together, our results indicate that preconditioning can inhibit the over-assembly of the GluR6-PSD95-MLK3 signaling module and the JNK3 activation. GluR6 subunit-containing kainite receptors play an important role in the preconditioning-induced neuronal survival and provide new insight into stroke therapy.

Troglitazone suppresses transforming growth factor-beta1-induced collagen type I expression in keloid fibroblasts

BACKGROUND

Peroxisome proliferator-activated receptor (PPAR)-gamma agonists are increasingly used in patients with diabetes and some studies have suggested a beneficial effect on organ fibrosis. However their effects on dermal fibrosis in keloids are unknown.

OBJECTIVE

To investigate the effect of the PPAR-gamma agonist troglitazone on transforming growth factor (TGF)-beta1-induced collagen type I expression in keloid fibroblasts.

METHODS

Keloid fibroblasts were cultured and exposed to different concentrations of troglitazone in the presence of TGF-beta1. The mRNA expression of PPAR-gamma was determined by semiquantitative reverse transcriptase-polymerase chain reaction. The protein of PPAR-gamma, Smad2, Smad3, phoshpo-Smad2/3 and collagen type I was determined by Western blotting and collagen synthesis was evaluated by measuring (3)H-proline incorporation. The effect of troglitazone on cell viability was evaluated by the colorimetric conversion of 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide.

RESULTS

PPAR-gamma was expressed at a moderate level in keloid fibroblasts. Troglitazone depressed TGF-beta1-stimulated collagen type I expression and collagen synthesis in keloid fibroblasts in a concentration-dependent manner. Moreover, troglitazone inhibited expression and phosphorylation of TGF-beta1-induced Smad2/3. Cell viability was unaffected. These inhibitory effects of troglitazone were reversed by the PPAR-gamma-specific antagonist GW9662.

CONCLUSIONS

Our data suggest that PPAR-gamma is present in keloid fibroblasts and PPAR-gamma activation inhibits TGF-beta1-induced collagen type I expression at least in part by decreasing collagen synthesis. PPAR-gamma may be a promising therapeutic target for keloids.

Anomalous photogalvanic effect of circularly polarized light incident on the two-dimensional electron gas in Al{x}Ga{1-x}N/GaN heterostructures at room temperature

Under normal incidence of circularly polarized light at room temperature, a charge current with swirly distribution has been observed in the two-dimensional electron gas in Al{0.25}Ga{0.75}N/GaN heterostructures. We believe that this anomalous charge current is produced by a radial spin current via the reciprocal spin Hall effect. It suggests a new way to research the reciprocal spin Hall effect and spin current on the macroscopic scale and at room temperature.

Coupling between neuronal nitric oxide synthase and glutamate receptor 6-mediated c-Jun N-terminal kinase signaling pathway via S-nitrosylation contributes to ischemia neuronal death

S-nitrosylation, as a post-translational protein modification, recently has been paid more and more attention in stroke research. S-nitrosylation regulates protein function by the mechanisms of covalent attachment that control the addition or the removal of nitric oxide (NO) from a cysteine thiol. The derivation of NO is established by the demonstration that, in cerebral neurons, NO mainly generates from neuronal nitric oxide synthase (nNOS) during the early stages of reperfusion. In the past researches, we demonstrate that global ischemia-reperfusion facilitates the activation of glutamate receptor 6 (GluR6) -mediated c-Jun N-terminal kinase (JNK) signaling pathway. The objective of this study is primarily to determine, during the early stages of reperfusion in rat four-vessel occlusion (4-VO) ischemic model, whether nNOS-derived NO affects the GluR6-mediated JNK signaling route via S-nitrosylation which is performed mainly by the biotin switch assay. Here, we show that administration of 7-nitroindazole, an inhibitor of nNOS, or ketamine, an antagonist of N-methyl-d-aspartate receptor (NMDAR), diminishes the increased S-nitrosylation of GluR6 induced by cerebral ischemia-reperfusion. In contrast, 2-amion-5,6-dihydro-6-methyl-4H-1,3-thiazine, an inhibitor of inducible NO synthase does not affect S-nitrosylation of GluR6. Moreover, treatment with sodium nitroprusside (SNP), an exogenous NO donor, increases the S-nitrosylation and phosphorylation of nNOS, leading to the attenuation of the increased S-nitrosylation of GluR6 and the assembling of GluR6* postsynaptic density protein 95 (PSD95)* mixed lineage kinase 3 (MLK3) signaling module induced by cerebral ischemia-reperfusion. The results also show that GluR6 downstream MLK3* mitogen activated protein kinase kinase 4/7* JNK signaling module and nuclear or non-nuclear apoptosis pathways are involved in the above signaling route. However, dithiothreitol (DTT) antagonizes the neuroprotection of SNP. Treatment with DTT alone, as a negative control, prevents S-nitrosylation of proteins, which indicates the existence of endogenously produced S-nitrosylation. These data suggest that GluR6 is S-nitrosylated by endogenous NO in cerebral ischemia-reperfusion, which is possibly correlated with NMDAR* PSD95* nNOS signaling module, and further activates GluR6* PSD95* MLK3 signaling module and JNK signaling pathway. In contrast, exogenous NO donor antagonizes the above action of endogenous NO generated from nNOS. Thus, our results provide the coupling of nNOS with GluR6 by S-nitrosylation during the early stages of ischemia-reperfusion, which can be a new approach for stroke therapy.

Reoperation of biliary tract by laparoscopy: a consecutive series of 26 cases

BACKGROUND

In the past, previous operation of biliary tract represented a contraindication to perform reoperation by laparoscopy. As experience with laparoscopic techniques and instrumentation has expanded, reoperation of biliary tract with laparoscope has become an accepted procedure in the management of cholelithiasis. We present our interesting experience with regard to reoperation of biliary tract by laparoscopy.

MATERIAL AND METHODS

Laparoscopic operation of biliary tract was performed on 3,674 consecutive patients from April, 1992 till June, 2005. Among these patients, 26 had a previous open operation of biliary tract and their clinical data were retrospectively analyzed as follows: seven cases had complicated intrahepatic bile duct stones (restricted at hepatic duct of the first and second order). Diameter of common bile duct in patients with common duct stones was above 1.2 cm, the number of stones for each patient was more than 3 and all the biggest stones exceeded 1 cm. In the 26 patients, preoperatively, stenosis of bile duct and malignant tumour were excluded by both radiological examination and detection of serological tumour markers.

RESULTS

The mean operative time was 125 min (75-190 min). Reoperations of biliary tract by laparoscope were successfully accomplished in 25 patients. One patient was converted to open operation and the common duct stones were removed by right angle forceps through short incision. None of the patients developed any severe complication, all of them recovered and were successfully discharged. Three cases with retained calculuses were successfully cured by removing these through the sinus tract of T tube.

CONCLUSIONS

Laparoscopic procedure is minimally invasive, safe and feasible for laparoscopic experts in case of reoperation of biliary tract. It is also a first method for patients for whom endoscopic sphincterotomy is contraindicated.

Laparoscopic primary choledochorrhaphy over endonasobiliary drainage tubes

BACKGROUND

The T-tube is widely used in laparoscopic choledochotomy to decompress the biliary tree. However, there are high morbidity rates related to the T-tube. This study reviewed the results of laparoscopic primary choledochorrhaphy over endonasobiliary drainage (ENBD) tubes to find an effective alternative to the T-tube for the performance of laparoscopic choledochotomy.

METHODS

From March 2003 to September 2005, 23 patients (9 men and 14 women) with choledocholithiasis underwent laparoscopic choledochotomy over ENBD tubes. The mean age of these patients was 47 years (range, 32-73 years). At admission, six patients had cholangitis. All the patients had ENBD tubes placed preoperatively after the failure of endoscopic sphincterotomy.

RESULTS

There was no conversion to open surgery. The mean operative time was 90 min (range, 70-150 min). There were no biliary complications such as bile leaks, biliary peritonitis, or pancreatitis. No residual stones were found by postoperative cholangiograms. The ENBD tubes were removed between postoperative days 7 and 9. The hospital stay ranged from 8 to 14 days, with 16 patients (70%) discharged on postoperative day 8. The complications were limited to one umbilical infection and one case of pneumonia. The median follow-up period was 24 months (range, 8-36 months), and none of the patients were readmitted with biliary symptoms.

CONCLUSION

Laparoscopic choledochotomy over ENBD tubes proved to be technically feasible and safe. The ENBD tube decompresses the biliary tree and allows for cholangiography after surgery. Its removal does not need to wait for tract maturation, which allows an earlier removal of the tube and a shorter postoperative hospital stay. Laparoscopic choledochotomy over ENBD tubes is an effective alternative to the T-tube in laparoscopic choledochotomy.

Ischemic preconditioning negatively regulates plenty of SH3s-mixed lineage kinase 3-Rac1 complex and c-Jun N-terminal kinase 3 signaling via activation of Akt

Activation of Akt/protein kinase B has been recently reported to play an important role in ischemic tolerance. We here demonstrate that the decreased protein expression and phosphorylation of phosphatase and tensin homolog deleted from chromosome 10 (PTEN) underlie the increased Akt-Ser-473 phosphorylation in the hippocampal CA1 subfield in ischemic preconditioning (IPC). Co-immunoprecipitation analysis reveals that Akt physically interacts with Rac1, a small Rho family GTPase required for mixed lineage kinase 3 (MLK3) autophosphorylation, and both this interaction and Rac1-Ser-71 phosphorylation induced by Akt are promoted in preconditioned rats. In addition, we show that Akt activation results in the disassembly of the plenty of SH3s (POSH)-MLK3-Rac1 signaling complex and down-regulation of the activation of MLK3/c-Jun N-terminal kinase (JNK) pathway. Akt activation results in decreased serine phosphorylation of 14-3-3, a cytoplasmic anchor of Bax, and prevents ischemia-induced mitochondrial translocation of Bax, release of cytochrome c, and activation of caspase-3. The expression of Fas ligand is also decreased in the CA1 region. Akt activation protects against apoptotic neuronal death as shown in TUNEL staining following IPC. Intracerebral infusion of LY294002 before IPC reverses the increase in Akt phosphorylation and the decrease in JNK signaling activation, as well as the neuroprotective action of IPC. Our results suggest that activation of pro-apoptotic MLK3/JNK3 cascade can be suppressed through activating anti-apoptotic phosphoinositide 3-kinase/Akt pathway induced by a sublethal ischemic insult, which provides a functional link between Akt and the JNK family of stress-activated kinases in ischemic tolerance.

Construction and characterization of the first bacterial artificial chromosome library for the cotton species Gossypium barbadense L

As the second most widely cultivated cotton, Gossypium barbadense is well known for its superior fiber properties and its high levels of resistance to Fusarium and Verticillium wilts. To enhance our ability to exploit these properties in breeding programs, we constructed the first bacterial artificial chromosome (BAC) library for this species. The library contains 167 424 clones (49 920 BamHI and 117 504 HindIII clones), with an estimated average insert size of 130 kb. About 94.0% of the clones had inserts over 100 kb, and the empty clones accounted for less than 4.0%. Contamination of the library with chloroplast clones was very low (0.2%). Screening the library with locus-specific probes showed that BAC clones represent 6.5-fold genome equivalents. This high-quality library provides an additional asset with which to exploit genetic variation for cotton improvement.

Neuroprotection against ischemic brain injury by a small peptide inhibitor of c-Jun N-terminal kinase (JNK) via nuclear and non-nuclear pathways

Our previous studies and the others have strongly suggested that c-Jun N-terminal kinase (JNK) signaling pathway plays a critical role in ischemic brain injury. Here we reported that Tat-JNK binding domain (JBD) of JNK-interacting protein-1 (JIP-1), a smaller 11-mer peptide corresponding to residues 153-163 of murine JIP-1 conjugated to Tat peptide, perturbed the assembly of JIP-1-JNK3 complexes, thus inhibiting the activation of JNK3 induced by ischemia/reperfusion in the vulnerable hippocampal CA1 subregion. As a result, Tat-JBD diminished the increased phosphorylation of c-Jun (a nuclear substrate of JNK) and the increased expression of Fas ligand induced by ischemia/reperfusion in the vulnerable hippocampal CA1 subregion. At the same time, through inhibiting phosphorylation of Bcl-2 (a cytosolic target of JNK) and the release of Bax from Bcl-2/Bax dimers, Tat-JBD attenuated Bax translocation to mitochondria and the release of cytochrome c induced by ischemia/reperfusion. Furthermore, the activation of caspase3 and hydrolyzation of poly-ADP-ribose-polymerase induced by brain ischemia/reperfusion were also significantly suppressed by preinfusion of the peptide Tat-JBD. Importantly, Tat-JBD showed neuroprotective effects on ischemic brain damage in vivo, and administration of the peptide after ischemia also achieved the same effects as preinfusion of the peptide did. Thus, our findings imply that Tat-JBD induced neuroprotection against ischemia/reperfusion in rat hippocampal CA1 region via inhibiting nuclear and non-nuclear pathways of JNK signaling. Taken together, these results indicate that Tat-JBD peptide provides a promising therapeutic approach for ischemic brain injury.

Enhanced expression of peroxisome proliferator-activated receptor gamma in epithelial ovarian carcinoma

The peroxisome proliferator-activated receptors (PPARs) belong to a subclass of nuclear hormone receptor that executes important cellular transcriptional functions. Previous studies have demonstrated the expression of PPARγ in several tumours including colon, breast, bladder, prostate, lung and stomach. This study demonstrates the relative expression of PPARγ in normal ovaries and different pathological grades of ovarian tumours of serous, mucinous, endometrioid, clear cell and mixed subtypes. A total of 56 ovarian specimens including 10 normal, eight benign, 10 borderline, seven grade 1, nine grade 2 and 12 grade 3 were analysed using immunohistochemistry. Immunoreactive PPARγ was not expressed in normal ovaries. Out of eight benign and 10 borderline tumours, only one tumour in each group showed weak cytoplasmic PPARγ expression. In contrast, 26 out of 28 carcinomas studied were positive for PPARγ expression with staining confined to cytoplasmic and nuclear regions. An altered staining pattern of PPARγ was observed in high-grade ovarian tumours with PPARγ being mostly localized in the nuclei with little cytoplasmic immunoreactivity. On the other hand, predominant cytoplasmic staining was observed in lower-grade tumours. Significantly increased PPARγ immunoreactivity was observed in malignant ovarian tumours (grade 1, 2 and 3) compared to benign and borderline tumours (χ²=48.80, P<0.001). Western blot analyses showed significant elevation in the expression of immunoreactive PPARγ in grade 3 ovarian tumours compared with that of normal ovaries and benign ovarian tumours (P<0.01). These findings suggest an involvement of PPARγ in the onset and development of ovarian carcinoma and provide an insight into the regulation of this molecule in the progression of the disease.

The neuroprotective effects of K252a through inhibiting MLK3/MKK7/JNK3 signaling pathway on ischemic brain injury in rat hippocampal CA1 region

It has been well documented that the activation of c-Jun N-terminal protein kinase (JNK) pathway and caspase-3 signal are involved in the delayed neuronal cell death in cerebral ischemia. In this study, we first detected the activation pattern of JNK signaling including mixed lineage kinase (MLK)3, mitogen-activated protein kinase kinase (MKK)7 and JNK3 in hippocampal CA1 and CA3/DG regions at various time points after 15 min of ischemia. These results indicated that cerebral ischemia induced the continuous activation of MLK3/MKK7/JNK3 cascade, which all had two active waves only in the CA1 region. We also detected the phosphorylation of JNK substrates c-Jun and Bcl-2, and the activation of a key protease of caspase-3 in CA1 region, which only had one active peak, respectively. Because K252a has recently been shown to be a potent inhibitor of MLK3 activity both in vivo and in vitro, we further examined the possible effects and mechanism of this interesting drug in cerebral ischemia. In our present paper, we found that administration of K252a 20 min prior to ischemia inhibited MLK3/MKK7/JNK3 signaling, Bcl-2 phosphorylation, the activation of c-Jun and caspase-3, but had no significant effects on these protein expressions. Additionally, pretreatment of K252a significantly increased the number of the surviving CA1 pyramidal cells at 5 days of reperfusion. Our results suggest that K252a play a neuroprotective role in ischemic injury via inhibition of the JNK pathway, involving the death effector of caspase-3. Thus, JNK signaling may eventually emerge as a prime target for novel therapeutic approaches to treatment of ischemic stroke, and K252a may serve as a potential and important neuroprotectant in therapeutic aspect in ischemic stroke.

Use of flyash as environmental and agronomic amendments

Coal combustion power plant flyash materials have been reported as useful soil amendments with agronomic and environmental benefits. This paper reports the efficacy of fluidized bed combustion (FBC) and flue gas desulfurization (FGD) byproducts, when amended with dairy, swine, and broiler litter manures, in reducing phosphorus (P) solubility and potential impact on water quality. At a rate of 400 g/kg, FBC reduced water soluble P by 60% for dairy and swine and 50% for broiler litter, as compared to un-treated control samples. Byproduct FGD had little effect when amended into dairy manure, but reduced water soluble P by nearly 80% when amended into swine and broiler manure at a rate of 250 g/kg. The amount of Ca added in the amendments together with pH of the mixture is the major contributing factor in soluble P reduction. Sequential extraction results showed that the flyash treatments shifted water soluble P into mainly bicarbonate extractable P. The latter is still considered available for crop uptake but less vulnerable for environmental losses. Coal combustion byproducts, when amended into manure and used properly, can provide a useful and viable option for improving nutrient management on animal farms.

Efficacy of alum and coal combustion by-products in stabilizing manure phosphorus

Animal manures contain large amounts of soluble phosphorus (P), which is prone to runoff losses when manure is surface-applied. Here we report the efficacy of alum and three coal combustion by-products in reducing P solubility when added to dairy, swine, or broiler litter manures in a laboratory incubation study. Compared with unamended controls, alum effectively reduced readily soluble P, determined in water extracts of moist manure samples with 1 h of shaking, for all three manures. The reduction ranged from 80 to 99% at treatment rates of 100 to 250 g alum kg(-1) manure dry matter. The fluidized bed combustion fly ash (FBC) reduced readily soluble P by 50 to 60% at a rate of 400 g kg(-1) for all three manures. Flue gas desulfurization by-product (FGD) reduced readily soluble P by nearly 80% when added to swine manure and broiler litter at 150 and 250 g kg(-1). Another by-product, anthracite refuse fly ash (ANT), was ineffective for all three manures. In all cases, reduction in readily soluble P is primarily associated with inorganic phosphorus (P(i)) with little change in organic phosphorus (P(o)). Sequential extraction results indicate that the by-product treatments shifted manure P from H2O-P into a less vulnerable fraction, NaHCO3 - P, while the alum treatment shifted the P into even more stable forms, mostly NaOH-P. Such shifts in P fractions would have little influence on P availability for crops over the long-term but would retard and reduce potential losses of P following manure applications.

Norepinephrine transporter (NET) is expressed in cardiac sympathetic ganglia of adult rat

The sympathetic nervous system plays a cardinal role in regulating cardiac function through releasing the neurotransmitter norepinephrine (NE). In comparison with central nervous system, the molecular mechanism of NE uptake in myocardium is not clear. In present study, we proved that in rat the CNS type of NE transporter (NET) was also expressed in middle cervical-stellate ganglion complex (MC-SG complex) which is considered to control the activity of heart, but not expressed in myocardium. The results also showed that NET expression level in right ganglion was significantly higher than in the left, rendering the greater capacity of NE uptake in right ventricle, a fact which may contribute to the maintenance of right ventricular function under pathologic state.

Stimulation of dopamine receptors inhibited Ca2+-calmodulin-dependent protein kinase II activity in rat striatal slices

AIM

To investigate the mechanism underlying dopaminergic neurotoxicity in the striatum during anoxia.

METHODS

Using rat striatal slices as an in vitro model, the activity of Ca2+-calmodulin-dependent protein kinase II (CCDPKII) was examined by the method of substrate phosphorylation 32P-incorporation.

RESULTS

Anoxia for 30 min greatly reduced CCDPKII activity by about 75 %. Reserpinization by repeated reserpine administration (1 mg . kg-1 . d-1 for 7 d, sc) preserved CCDPK II activity against the anoxia-induced decrease (about 40 % of control). The activity of CCDPKII was reduced significantly by exposure of rat striatal slices to micromolar concentrations of dopamine in the presence of extracellular Ca2+. Omission of Ca2+ in the incubation medium (with addition of 1 mmol/L egtazic acid) diminished the dopamine-induced decrease of the kinase activity. Application of apomorphine, a non-selective dopamine receptor agonist, produced a similar concentration-related decrease of CCDPKII activity. Exposure to SKF38393 (selective D1-like receptor agonist) or quinpirole (selective D2-like receptor agonist) also inhibited the kinase activity. The dopamine-induced decrease of CCDPKII activity was attenuated by preincubation with Sch-23390 (selective D1-like receptor antagonist) or domperidone (selective D2-like receptor antagonist).

CONCLUSION

Dopamine is involved in the anoxia-induced inhibition of CCDPKII activity by activation of both D1-like and D2-like receptors and influx of Ca2+, which may contribute to dopamine-mediated striatal neuronal damage.