K(ATP) channel action in vascular tone regulation: from genetics to diseases / 生理学报

ATP-sensitive potassium (K(ATP)) channels are widely distributed in vasculatures, and play an important role in the vascular tone regulation. The K(ATP) channels consist of 4 pore-forming inward rectifier K(+) channel (Kir) subunits and 4 regulatory sulfonylurea receptors (SUR). The major vascular isoform of K(ATP) channels is composed of Kir6.1/SUR2B, although low levels of other subunits are also present in vascular beds. The observation from transgenic mice and humans carrying Kir6.1/SUR2B channel mutations strongly supports that normal activity of the Kir6.1/SUR2B channel is critical for cardiovascular function. The Kir6.1/SUR2B channel is regulated by intracellular ATP and ADP. The channel is a common target of several vasodilators and vasoconstrictors. Endogenous vasopressors such as arginine vasopressin and α-adrenoceptor agonists stimulate protein kinase C (PKC) and inhibit the K(ATP) channels, while vasodilators such as β-adrenoceptor agonists and vasoactive intestinal polypeptide increase K(ATP) channel activity by activating the adenylate cyclase-cAMP-protein kinase A (PKA) pathway. PKC phosphorylates a cluster of 4 serine residues at C-terminus of Kir6.1, whereas PKA acts on Ser1387 in the nucleotide binding domain 2 of SUR2B. The Kir6.1/SUR2B channel is also inhibited by oxidants including reactive oxygen species allowing vascular regulation in oxidative stress. The molecular basis underlying such a channel inhibition is likely to be mediated by S-glutathionylation at a few cysteine residues, especially Cys176, in Kir6.1. Furthermore, the channel activity is augmented in endotoxemia or septic shock, as a result of the upregulation of Kir6.1/SUR2B expression. Activation of the nuclear factor-κB dependent transcriptional mechanism contributes to the Kir6.1/SUR2B channel upregulation by lipopolysaccharides and perhaps other toll-like receptor ligands as well. In this review, we summarize the vascular K(ATP) channel regulation under physiological and pathophysiological conditions, and discuss the importance of K(ATP) channel as a potentially useful target in the treatment and prevention of cardiovascular diseases.

Sequence and promoter efficacy analysis of avian leukosis virus subgroup J strains of different pathotypes / 病毒学报

To characterize the long terminal repeat (LTR) of the ALV-J strain which can induce hemangioma, fragments of provirus LTR of the three different ALV-J strains SCAU-HN06, NX0101 and JS-nt were amplified with a pair of specific primers, then cloned and subjected to sequence analysis. In comparison with the prototype ALV-J strains HPRS-103 and ADOL-7501, the LTRs of domestic strains (SCAU-HN06, NX0101, JS-nt and SD07lk1) had an 88.0%-97.2% nucleotide sequence identity; the U5 and R regions in the LTR had a high nucleotide similarity, while the U3 region in the LTR showed significant variance. The LTR fragments from the different ALV-J strains were inserted into the upstream of bacterial CAT gene of the plasmid pCAT-Basic, respectively. The resultant recombinant plasmids were transfected into DF-1 cells. The transfected cells were harvested 48 h post-transfection, and cell lysates were prepared for CAT expression detection. The CAT assay was performed using CAT-ELISA. The results showed that the promoter activity of the LTRSCAU-HNO6 was a little higher than those of LTRJS-nt and LTRNX0101, but there was no significant difference in the promoter activity among the compared LTRs.

Role of prosurvival molecules in the action of lidamycin toward human tumor cells / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>Lidamycin, an enediyne antibiotic, leads to apoptosis and mitotic cell death of human tumor cells at high and low concentrations. The reason why tumor cells have distinct responses to lidamycin remains elusive. This study was to elucidate if cellular prosurvival molecules are involved in these responses.</p><p><b>METHODS</b>Cleavage of chromatin and DNA was observed by chromatin condensation and agarose gel electrophoresis. Accumulation of rhodamine 123 in lidamycin-treated cells was assayed by flow cytometry. Cell multinucleation was detected by staining with Hoechst 33342. Western blot and senescence-associated beta-galactosidase (SA-beta-gal) staining were used to analyze protein expression and senescence-like phenotype, respectively.</p><p><b>RESULTS</b>SIRT1 deacetylase remained unchanged in 0.5 nmol/L lidamycin whereas cleavage occurred when apoptosis was induced by lidamycin. Increased FOXO3a, SOD-1 and SOD-2 expression and transient phosphorylation of ERK were detected after exposure of human hepatoma BEL-7402 cells to 0.5 nmol/L lidamycin. High expressions of SIRT1 and Akt were found in colon carcinoma HCT116 p53 knock-out cells exposed to lidamycin. Degradation of PARP and p53 by lidamycin as a substitute for SIRT1 and Akt was confirmed with caspase inhibitor Q-VD-OPh and proteasome inhibitor MG132. Resistance to lidamycin-induced DNA cleavage was observed in breast cancer doxorubicin-resistant MCF-7 cells. This was not induced by P-glycoprotein as no accumulation of rhodamine 123 was detected in the resistant cells following exposure to lidamycin. In contrast to sensitive MCF-7 cells, a lower multinucleation rate for the resistant cells was measured following exposure to equal concentrations of lidamycin.</p><p><b>CONCLUSIONS</b>Cellular prosurvival molecules, such as SIRT1, Akt, SOD-1, SOD-2 and other unknown factors can influence the action of lidamycin on human tumor cells.</p>

Secretory expression of recombinant porcine zona pellucida glycoprotein-3alpha (rpZP3alpha) in Pichia pastoris / 生物工程学报

To obtain the recombinant pZP3alpha protein for the study of the contraceptive vaccines, the DNA sequence (446-1423) encoding purified pZP3alpha was inserted into a vector--pPICZalphaA. The recombinant plasmid pPICZalphaA-pZP3alpha was linearized and then transformed into Pichia pastoris GS115 by electroporation. Engineering strains were attained by screening with zeocin and induced to produce rpZP3alpha in high-density fermentation. Then rpZP3alpha was purified by Cu2+ metal affinity column chromatography from the separated and concentrated fermentative supernatants. The purified rpZP3alpha was identified by SDS-PAGE and Western blot, and the quantity, purity and rate of recovery of the rpZP3alpha were analyzed by Quantity One software. One male rabbit was immunized with the Cu-NTA-purified rpZP3alpha. The antibody responses against rpZP3alpha and porcine ZP were detected by ELISA and the indirect immunofluorescence. Engineering strains expressing rpZP3alpha in secretion were constructed. A 46kD component named rpZP3alpha which can react with anti-pZP3 antibody was purified from fermentative supernatants of engineering strains and the average yield of purified rpZP3alpha obtained from fermentative supernatants was 8mg/L. The purity and the rate of recovery were up to 92% and 63% respectively. The anti-rpZP3alpha antiserum was prepared by immunization of a male rabbit with purified rpZP3alpha. This anti-rpZP3alpha antiserum could react with rpZP3alpha and purified pZP3 in ELISA and bind to porcine zona pellucida which produced bright green fluorescence in the indirect immunofluorescence. The rpZP3alpha (46kD) protein could be successfully expressed in the Pichia pastoris expression system. And this protein retained the immunogenic activity of natural pZP3.

Glossopharyngeal neuralgia:MR findings / 中华放射学杂志

Objective To investigate the possibility of MRI on visualizing the relationship between glossopharyngeal nerve and surrounding vessels,and to evaluate the significance of MRI in the diagnosis and treatment of glossopharyngeal neuralgia.Methods MRI findings were analyzed retrospectively in 12 patients with glossopharyngeal neuralgia,and were compared with surgical findings and effect of pain relief.Results The artery compression or contact of the glossopharyngeal entry zone,as revealed during operation in l0 patients with glossopharyngeal neuralgia,was visualized on MRI in 9 and not seen in 1.The venous compression of the glossopharyngeal entry zone was not identified on MRI in 1.The conglutinative arachnoids of the glossopharyngeal entry zone was not visualized on MRI in 1.MRI demonstrated the affected glossopharyngeal nerve root entry zone was compressed or contacted by the posterior inferior cerebellar artery (PICA)in 8 patients and by the vertebral artery in 1 patient.One patient's offending vessel was confirmed to be the anterior inferior cerebellar artery(AICA)by the operation,and the surgical findings were corresponded with MRI in others.Vascular compression or contact of the affected glossopharyngeal nerve was not visualized on MRI in 3 patients,and operation confirmed that the glossopharyngeal nerve root entry zone was compressed by unknown artery in 1,by small vein in 1,and by eonglutinative araehnoids in 1, respectively.Eight patients presented with symptoms of the ipsilateral trigeminal neuralgia concurrently.The compression of the affected trigeminal nerve root by superior cerebellar artery(SCA)was visualized on MRI in 6 patients,and operation did not reveal the source of artery compression in 1 and corresponded with MRI findings in other 5 cases.Vascular compression of affected trigeminal nerve was not visualized on MRI in 2 patients,and intraoperative inspection revealed that trigeminal nerve root was compressed by draining vein of brainstem in 1 and not compressed by any vessels in 1.All patient's neuralgia resolved after microvascular decompression of glossopharyngeal nerve and trigeminal nerve.Conclusion It is possible to visualize the glossopharyngeal and surrounding arteries on MRI,and it is of great significance in the diagnosis and treatment of this kind of glossopharyngeal neuralgia.