Celastrol targets mitochondrial respiratory chain complex I to induce reactive oxygen species-dependent cytotoxicity in tumor cells

<p>Abstract</p> <p>Background</p> <p>Celastrol is an active ingredient of the traditional Chinese medicinal plant <it>Tripterygium Wilfordii</it>, which exhibits significant antitumor activity in different cancer models <it>in vitro </it>and <it>in vivo</it>; however, the lack of information on the target and mechanism of action of this compound have impeded its clinical application. In this study, we sought to determine the mode of action of celastrol by focusing on the processes that mediate its anticancer activity.</p> <p>Methods</p> <p>The downregulation of heat shock protein 90 (HSP90) client proteins, phosphorylation of c-Jun NH2-terminal kinase (JNK), and cleavage of PARP, caspase 9 and caspase 3 were detected by western blotting. The accumulation of reactive oxygen species (ROS) was analyzed by flow cytometry and fluorescence microscopy. Cell cycle progression, mitochondrial membrane potential (MMP) and apoptosis were determined by flow cytometry. Absorption spectroscopy was used to determine the activity of mitochondrial respiratory chain (MRC) complexes.</p> <p>Results</p> <p>Celastrol induced ROS accumulation, G2-M phase blockage, apoptosis and necrosis in H1299 and HepG2 cells in a dose-dependent manner. N-acetylcysteine (NAC), an antioxidative agent, inhibited celastrol-induced ROS accumulation and cytotoxicity. JNK phosphorylation induced by celastrol was suppressed by NAC and JNK inhibitor SP600125 (SP). Moreover, SP significantly inhibited celastrol-induced loss of MMP, cleavage of PARP, caspase 9 and caspase 3, mitochondrial translocation of Bad, cytoplasmic release of cytochrome c, and cell death. However, SP did not inhibit celastrol-induced ROS accumulation. Celastrol downregulated HSP90 client proteins but did not disrupt the interaction between HSP90 and cdc37. NAC completely inhibited celastrol-induced decrease of HSP90 client proteins, catalase and thioredoxin. The activity of MRC complex I was completely inhibited in H1299 cells treated with 6 μM celastrol in the absence and presence of NAC. Moreover, the inhibition of MRC complex I activity preceded ROS accumulation in H1299 cells after celastrol treatment.</p> <p>Conclusion</p> <p>We identified ROS as the key intermediate for celastrol-induced cytotoxicity. JNK was activated by celastrol-induced ROS accumulation and then initiated mitochondrial-mediated apoptosis. Celastrol induced the downregulation of HSP90 client proteins through ROS accumulation and facilitated ROS accumulation by inhibiting MRC complex I activity. These results identify a novel target for celastrol-induced anticancer activity and define its mode of action.</p

Proteomic Analyses Reveal Common Promiscuous Patterns of Cell Surface Proteins on Human Embryonic Stem Cells and Sperms

BACKGROUND: It has long been proposed that early embryos and reproductive organs exhibit similar gene expression profiles. However, whether this similarity is propagated to the protein level remains largely unknown. We have previously characterised the promiscuous expression pattern of cell surface proteins on mouse embryonic stem (mES) cells. As cell surface proteins also play critical functions in human embryonic stem (hES) cells and germ cells, it is important to reveal whether a promiscuous pattern of cell surface proteins also exists for these cells. METHODS AND PRINCIPAL FINDINGS: Surface proteins of hES cells and human mature sperms (hSperms) were purified by biotin labelling and subjected to proteomic analyses. More than 1000 transmembrane or secreted cell surface proteins were identified on the two cell types, respectively. Proteins from both cell types covered a large variety of functional categories including signal transduction, adhesion and transporting. Moreover, both cell types promiscuously expressed a wide variety of tissue specific surface proteins, and some surface proteins were heterogeneously expressed. CONCLUSIONS/SIGNIFICANCE: Our findings indicate that the promiscuous expression of functional and tissue specific cell surface proteins may be a common pattern in embryonic stem cells and germ cells. The conservation of gene expression patterns between early embryonic cells and reproductive cells is propagated to the protein level. These results have deep implications for the cell surface signature characterisation of pluripotent stem cells and germ cells and may lead the way to a new area of study, i.e., the functional significance of promiscuous gene expression in pluripotent and germ cells

Thermo-Economic Assessments on a Heat Storage Tank Filled with Graded Metal Foam

To save and better deploy waste heat, the use of a mobilized heat storage system (MHSS) with phase change enhancement means is developed. In this paper, three kinds of gradient structures (positive gradient, negative gradient, and non-gradient) are designed in the MHSS system. The uniform porosity is 94% in the non-gradient structure, and the gradient porosities are 86%, 93%, and 98% in the gradient structure, respectively. Numerical models are developed to explore the contribution of the graded metal foam structure to the heat storage and release process. An economic analysis and comparison of MHSS systems with different heat transfer models are carried out. The results show that the positive gradient case can promote the thermal cycle of the melting and solidification process, while the negative gradient case inhibits the thermal cycle. The positive gradient case can reduce the melting time by 9.7% and the solidification time by 4.4%, while the negative gradient can prolong the melting time by 31.4% and the solidification time by 35.9%. Although graded metal foam increases the initial investment by 76.09%, the 1 KW·h heat cost of graded metal foam is reduced by 10.63% compared to pure phase change material (PCM). It is cost-effective in the long run of thermal cycles

Treatment strategy for spontaneous coronary artery dissection based on anatomical characteristics

Abstract Objectives To compare the clinical and angiographic characteristics of high-risk and low-risk spontaneous coronary artery dissection (SCAD) patients to determine the optimal treatment strategy. Background SCAD is a rare and emerging cause of acute coronary syndrome and sudden cardiac death, especially in young female patients. However, the indication of percutaneous coronary intervention (PCI) in patients with SCAD remains elusive. Methods We evaluated the clinical and angiographic characteristics of all SCAD patients admitted to our center from 2012 to 2020. The outcomes of the high-risk and low-risk SCAD patients according to the location of the lesion segment with dissection or intramural hematoma were compared. Further analyses were performed to evaluate the vessel healing or residual dissection in the patients receiving the follow-up angiography. Results A total of 81 SCAD patients were enrolled in the present study, in which 38 patients were categorized as high-risk group, defined as involvement of the left main artery or proximal segment of any main coronary artery. PCI was the more common treatment approach in the high-risk group (68.4%), while conservative treatment was more common in the low-risk group (62.8%). The incidence of major adverse cardiac events, defined as cardiac death, myocardial infarction, unstable angina pectoris, severe arrhythmias, or heat failure, within 1 year follow-up was similar between the two groups. 57 patients (70.4%) received the follow-up angiography after 1 year. The high- and low-risk groups had a similar rate of vessel healing among the PCI treatment patients. However, more patients achieved spontaneous healing in the low-risk group than the high-risk group among the conservative treatment patients (86.4% vs. 33.3%, p < 0.05). Conclusions Conservative management remains the recommended treatment strategy for the low-risk SCAD patients. PCI could be considered in high-risk SCAD patients with favorable clinical outcomes and vessel healing. Characterization of lesion anatomy may be an important indicator for treatment decision

Carbon Dioxide Microbubble Bursting Ionization Mass Spectrometry

Aerosols generated by bubble bursting have been proved to promote the extraction of analytes and have ultrahigh electric fields at their water–air interfaces. This study presented a simple and efficient ionization method, carbon dioxide microbubble bursting ionization (CDMBI), without the presence of an exogenous electric field (namely, zero voltage), by simulating the interfacial chemistries of sea spray aerosols. In CDMBI, microbubbles are generated in situ by continuous input of carbon dioxide into an aqueous solution containing low-concentration analytes. The microbubbles extract low- and high-polarity analytes as they pass through the aqueous solution. Upon reaching the water–air interface, these microbubbles burst to produce charged aerosol microdroplets with an average diameter of 260 μm (8.1–10.4 nL in volume), which are immediately transferred to a mass spectrometer for the detection and identification of extracted analytes. The above analytical process occurs every 4.2 s with a stable total ion chromatogram (relative standard deviation: 9.4%) recorded. CDMBI mass spectrometry (CDMBI-MS) can detect surface-active organic compounds in aerosol microdroplets, such as perfluorooctanoic acid, free fatty acids epoxidized by bubble bursting, sterols, and lecithins in soybean and egg, with the limit of detection reaching the level of fg/mL. In addition, coupling CDMBI-MS with an exogenous voltage yields relatively weak gains in ionization efficiency and sensitivity of analysis. The results suggested that CDMBI can simultaneously accomplish both bubbling extraction and microbubble bursting ionization. The mechanism of CDMBI involves bubbling extraction, proton transfer, inlet ionization, and electrospray-like ionization. Overall, CDMBI-MS can work in both positive and negative ion modes without necessarily needing an exogenous high electric field for ionization and quickly detect trace surface-active analytes in aqueous solutions

Correction to: EBV-miR-BART8-3p induces epithelial-mesenchymal transition and promotes metastasis of nasopharyngeal carcinoma cells through activating NF-κB and Erk1/2 pathways

Following publication of the original article [1], the authors reported two errors in the article. In the caption of Figure 1c the sentence “The 20 most highly upregulated EBV BART miRNAs identified between NPC specimens and normal nasopharyngeal mucosal specimens" should be corrected as “The highly upregulated EBV BART miRNAs identified between NPC specimens and normal nasopharyngeal mucosal specimens”

HPV16/18 L1 VLP vaccine induces cross-neutralizing antibodies that may mediate cross-protection

View of the cliffs, looking south, showing the town of Thira along the cliff's edge; Santorini is a small, circular group of volcanic islands located in the Aegean Sea, about 200 km south-east from the mainland of Greece. It is also known by the name of the largest island in the archipelago, Thera (or Thira). It is the southernmost member of the Cyclades group of islands, with an area of approximately 73 sq km (28 sq mi), and in 2001 had an estimated population of 13,600. A giant central lagoon, more or less rectangular and measuring about 12 km by 7 km (8 mi by 4 mi), is surrounded by 300 m (984 ft) high sheer cliffs on three sides. The island slopes downward from the cliffs to the surrounding Mediterranean sea. On the fourth side, the lagoon is separated from the Mediterranean by another much smaller island called Therasia, also with cliffs. The lagoon is joined to the sea in two places, in the northwest and southwest. The water in the centre of the lagoon is nearly 400 m (1,300 ft) deep, so it is an ideal safe harbour for even the biggest ships. The island's ports are all in the lagoon and there are no ports on the outside of the island. The towns of Santorini cling to the top of the cliff looking down on the lagoon. It is the most active volcanic centre in the Aegean Arc, though what remains today is largely a water-filled caldera. The name Santorini was given to it by the Latin empire in the thirteenth century and is a reference to Saint Irene. Before then it was called Kallistē ("the most beautiful one"), Strongylē ("the circular one"), or Thera. The island was the site of one of the largest volcanic eruptions of the last several thousand years when it erupted cataclysmically about 3,500 years ago. The eruption left a large caldera surrounded by volcanic ash deposits hundreds of feet deep, and its effects may have indirectly led to the collapse of the Minoan civilization on the island of Crete, 110 km (70 mi) to the south. One popular theory holds that the Thera eruption is the source of the legend of Atlantis. Source: Wikipedia; http://en.wikipedia.org/wiki/Main_Page (accessed 7/16/2008

Oral and systemic HPV antibody kinetics post-vaccination among HIV-positive and HIV-negative men

Duration and functional aspects of the oral and systemic antibody responses following HPV vaccination in HIV-negative (HIV-) and HIV-positive (HIV+) men are not well characterized. Oral and systemic HPV-16 and HPV-18-specific antibody levels were evaluated over 18-months of follow-up, in HIV+ and HIV- men. Sera and oral gargles from 147 HIV- men, ages 27-45 and 75 HIV+ men, ages 22-61, who received 3-doses of quadrivalent HPV vaccine were tested for HPV-16 and HPV-18 antibodies at Day 1, Month 7 (1 month post-dose 3), and Month 18 (12 months post-dose 3) and HPV avidity (Day 1, and Month 7) using L1-VLP ELISA. All individuals seroconverted, regardless of HIV-status, following 3-doses of vaccine for HPV-16 and HPV-18. Serum HPV-16 and HPV-18 antibody geometric mean levels were &gt;2-fold lower in HIV+ compared to HIV- men at Month 7 (HPV-16: 808.5 versus 2119.8 EU/mL, and HPV-18: 285.8 versus 611.6 EU/mL, p &lt; 0.001) but not significantly different at Month 18 (HPV-16: 281.8 versus 359.7 EU/mL, p = 0.145, and HPV-18: 120.2 versus 93.4 EU/mL, p = 0.372). Post-vaccination, only oral HPV-16 antibody levels at Month 7 were significantly different between HIV+ and HIV- men (127.7 versus 177.1 EU/mg of IgG, p = 0.008). Among baseline HPV-seronegative men, circulating levels of HPV-16 and HPV-18 antibodies were up to &gt;3 fold lower in HIV+ men, at Months 7 and 18. In contrast, levels of HPV-16 and HPV-18 antibodies after vaccination were not inferior in baseline HPV-seropositive, HIV+ men. HPV-16 and HPV-18 avidity was lower among HIV+ compared to HIV- men at Month 7 (HPV-16: 1.95 M versus 2.12 M, p = 0.027; HPV-18: 1.50 M versus 1.72 M, p &lt; 0.001). Although differences in peak antibody levels were observed between HIV+ and HIV- men following 3 doses of vaccine, plateau antibody levels were overall comparable, and avidity was relatively high for both groups. These data indicate that the vaccine induced antibody affinity maturation in both HIV+ and HIV- men and will likely result in long-term protective immune responses