The involvement of mitochondrial apoptotic pathway in eugenol-induced cell death in human glioblastoma cells

Eugenol, a natural phenolic constituent of clove oil, has a wide range of applications in medicine as a local antiseptic and anesthetic. However, the effect of eugenol on human glioblastoma is unclear. This study examined whether eugenol elevated intracellular free Ca²⁺ levels ([Ca²⁺]_i) and induced apoptosis in DBTRG-05MG human glioblastoma cells. Eugenol evoked [Ca²⁺]_i rises which were reduced by removing extracellular Ca²⁺. Eugenol-induced [Ca²⁺]_i rises were not altered by store-operated Ca²⁺ channel blockers but were inhibited by the PKC inhibitor GF109203X and the transient receptor potential channel melastatin 8 (TRPM8) antagonist capsazepine. In Ca²⁺-free medium, pretreatment with the endoplasmic reticulum Ca²⁺ pump inhibitor thapsigargin (TG) or 2,5-di-tert-butylhydroquinone (BHQ) abolished eugenol-induced [Ca²⁺]_i rises. The phospholipase C (PLC) inhibitor U73122 significantly inhibited eugenol-induced [Ca²⁺]_i rises. Eugenol killed cells which were not reversed by prechelating cytosolic Ca²⁺ with 1,2-bis(2-aminophenoxy) ethane-N,N,N′,N′-tetraacetic acid-acetoxymethyl ester (BAPTA-AM). Eugenol induced apoptosis through increasing reactive oxygen species (ROS) production, decreasing mitochondrial membrane potential, releasing cytochrome c and activating caspase-9/caspase-3. Together, in DBTRG-05MG cells, eugenol evoked [Ca²⁺]_i rises by inducing PLC-dependent release of Ca²⁺ from the endoplasmic reticulum and caused Ca²⁺ influx possibly through TRPM8 or PKC-sensitive channels. Furthermore, eugenol induced the mitochondrial apoptotic pathway.     

旋毛虫Hsp70与Ts87融合蛋白的构建表达及鉴定

本文构建并表达了旋毛虫热休克蛋白70（Ts－Hsp70）与排泄分泌抗原Ts87的融合蛋白,并对融合蛋白进行纯化和免疫学鉴定。本研究采用限制性内切酶EcoRⅠ酶切位点将目的基因Ts－Hsp70与Ts87相连接,插入pET28－a （＋）质粒,转入大肠埃希菌BL21（DE3）中诱导表达、纯化,获得的融合蛋白rTs－Hsp70－Ts87用Western blot的方法鉴定。经PCR、酶切鉴定、测序分析,结果显示,目的基因片段大小为2721 bp,构建的重组质粒与预期相符。经IPTG诱导表达,通过镍离子柱层析纯化复性后得到可溶的融合蛋白rTs－Hsp70－Ts87,其相对分子质量约为100 kDa; Western blot结果显示,该蛋白可被抗His标签单抗、 rTs－Hsp70免疫血清、 rTs87免疫血清识别。以上结果表明,本研究成功构建并表达了融合蛋白rTs－Hsp70－Ts87,为进一步研究rTs－Hsp70－Ts87的免疫保护性,开发新的有效抗旋毛虫病的疫苗奠定基础。     

Protection against Klebsiella pneumoniae Using Lithium Chloride in an Intragastric Infection Model

Intragastric Klebsiella pneumoniae infections of mice can cause liver abscesses, necrosis of liver tissues, and bacteremia. Lithium chloride, a widely prescribed drug for bipolar mood disorder, has been reported to possess anti-inflammatory properties. Using an intragastric infection model, the effects of LiCl on K. pneumoniae infections were examined. Providing mice with drinking water containing LiCl immediately after infection protected them from K. pneumoniae-induced death and liver injuries, such as necrosis of liver tissues, as well as increasing blood levels of aspartate aminotransferase and alanine aminotransferase, in a dose-dependent manner. LiCl administered as late as 24 h postinfection still provided protection. Monitoring of the LiCl concentrations in the sera of K. pneumoniae-infected mice showed that approximately 0.33 mM LiCl was the most effective dose for protecting mice against infections, which is lower than the clinically toxic dose of LiCl. Surveys of bacterial counts and cytokine expression levels in LiCl-treated mice revealed that both were effectively inhibited in blood and liver tissues. Using in vitro assays, we found that LiCl (5 μM to 1 mM) did not directly interfere with the growth of K. pneumoniae but made K. pneumoniae cells lose the mucoid phenotype and become more susceptible to macrophage killing. Furthermore, low doses of LiCl also partially enhanced the bactericidal activity of macrophages. Taken together, these data suggest that LiCl is an alternative therapeutic agent for K. pneumoniae-induced liver infections.