Changran Zhang

Hydrogen sulfide protects PC12 cells against reactive oxygen species and extracellular signal-regulated kinase 1/2-mediated downregulation of glutamate transporter-1 expression induced by chemical hypoxia

Hypoxia and/or ischemia are implicated in neurodegenerative disorders. In these diseases, hypoxia/ischemia may induce oxidative stress, including production of reactive oxygen species (ROS), which result in a decrease in glutamate transporter expression. Hydrogen sulfide (H2S), as the third gasotransmitter, has neuroprotective effects and potent antioxidant properties. In the present study, we investigated the role of glutamate transporter-1 (GLT-1) in the protection of H2S against chemical hypoxia-induced injury in PC12 cells. We found that cobalt chloride (CoCl2), a chemical hypoxia agent, reduced the expression of GLT-1 in a time-dependent manner. Pretreatment with NaHS (a donor of H2S) reversed the CoCl2-induced downregulation of GLT-1 expression. Pretreatment with DHK (a selective inhibitor of GLT-1) for 30 min prior to NaHS preconditioning significantly inhibited the cytoprotection of H2S against CoCl2-induced injuries, leading to an increase in cytotoxicity and apoptosis as well as to a loss of mitochondrial membrane potential (MMP). In addition, we found that similar to the effect of NaHS, pretreatment with NAC (a ROS scavenger) or U0126 (a MEK1/2 inhibitor) blocked the downregulation of GLT-1 expression induced by CoCl2. Collectively, we demonstrated for the first time that ROS and extracellular signal-regulated kinase 1/2 (ERK1/2)-mediated reduction of GLT-1 expression may be involved in chemical hypoxia-induced neural injury and that H2S attenuates this injury partly by upregulating GLT-1 expression in PC12 cells.

Increased expression of heat shock protein 90 under chemical hypoxic conditions protects cardiomyocytes against injury induced by serum and glucose deprivation

Heat shock proteins (HSPs) are critical for adaptation to hypoxia and/or ischemia. Previously, we demonstrated that cobalt chloride (CoCl2), a well-known hypoxia mimetic agent, is an inducer of HSP90. In the present study, we tested the hypothesis that CoCl₂-induced upregulation of HSP90 is able to provide cardioprotection in serum and glucose-deprived H9c2 cardiomyocytes (H9c2 cells). Cell viability was detected using a CCK-8 assay, while HSP90 expression was detected via western blotting. The findings of this study showed that serum and glucose deprivation (SGD) induced significant cytotoxicity, overproduction of reactive oxygen species (ROS) and a loss of mitochondrial membrane potential (MMP) in H9c2 cells. In addition, SGD downregulated the expression of HSP90 in a time-dependent manner. The selective inhibitor of HSP90 17-allylamino-17-demethoxygeldanamycin (17-AAG) aggravated SGD-induced cytotoxicity. CoCl₂ at 100 µM time-dependently enhanced the expression of HSP90. Treatment with CoCl₂ from 50 to 200 µM significantly attenuated cytotoxicity and the downregulation of HSP90 expression induced by SGD for 24 h, respectively. Notably, pretreatment of H9c2 cells with 17-AAG at 2 µM for 60 min before exposure to both CoCl2 (100 µM) and SGD significantly blocked the CoCl2-induced cardioprotective effect, demonstrated by decreased cell viability and MMP loss, as well as increased ROS generation. Taken together, these results suggest that HSP90 may be one of the endogenous defensive mechanisms for resisting ischemia-like injury in H9c2 cells, and that HSP90 plays an important role in chemical hypoxia-induced cardioprotection against SGD-induced injury by its antioxidation and preservation of mitochondrial function.

Interleukin-12 and interleukin-2 alone or in combination against the infection in invasive pulmonary aspergillosis mouse model

Aspergillus fumigatus is an intracellular opportunistic fungus causing invasive pulmonary mycosis, characterised by hyphal invasion and destruction of pulmonary tissue. Th1 cytokines could enhance fungicidal activity. The effects from the combination of interleukin‐12 (IL‐12) and IL‐2 are rarely known in invasive pulmonary aspergillosis infection. To assess the cleaning of A. fumigatus infection in the pulmonary tissues by IL‐12 and IL‐2, interferon‐γ (IFN‐γ) was detected in the sera using ELISA, quantification of IFN‐γ mRNA using real‐time RT‐PCR and lung Colony‐forming unit was assayed by cultivation. Morphology was analysed by histopathological examination. Our results showed that IL‐12 and/or IL‐2 could enhance the IFN‐γ expression in the pulmonary tissue, reduce the colony load in the pulmonary tissue and increase the survival rate of mouse. The combination of IL‐12 and IL‐2 could assist in increasing the IFN‐γ expression in the pulmonary tissue, but neither reduce colony load in the pulmonary tissue nor increase the survival rate of mouse significantly. It was demonstrated that IL‐12 and IL‐2 were strong immunomodulatory cytokines as a prerequisite for protecting the host from infectious agents.

Case-Control Study on Impact of the Telomerase Reverse Transcriptase Gene Polymorphism and Additional Single Nucleotide Polymorphism (SNP)- SNP Interaction on Non-Small Cell Lung Cancers Risk in Chinese Han Population.

To investigate the impact of telomerase reverse transcriptase (TERT) gene polymorphism and additional SNP–SNP interaction on non‐small cell lung cancer (NSCLC) risk in Chinese population.

The serum glucan level and pathological changes of antifungal treatment for lower respiratory tract infection of Candida albicans

Due to the fact that Candida albicans colonizes in the upper respiratory tracts of healthy people, whether or not its isolation from airway secretions is sufficient to warrant treatment remains controversial. The animal models of immunosuppressive rats with pulmonary candidiasis were established by the intratracheal inoculating suspensions of C. albicans, and the animals were divided into the following three groups: (1) antifungal treatment group, (2) saline control group, and (3) blank control group. We noted the following in our studies: (1) The fungal load of the saline control group gradually increased such that it was higher than those of the antifungal treated group and was significant from the fourth day of treatment (P < 0.01). (2) The serum (1,3)-β-D-glucan (BG) in the saline control group also gradually increased so that it was significantly higher than found with the treated group by the sixth day of treatment (P < 0.05), and in fact, the rank of pulmonary colony count and BG in the two groups at different time points showed an almost perfect linear correlation. (3) The median survival period of the rats in the antifungal treated group and saline control group was 15 and 8 days respectively, no rats died in the blank control group. (4) The lung lesions from the saline control group gradually became more aggravated than those in the antifungal treated group; no significant pathological changes were found in the blank control group. Antifungal treatment (micafungin) is capable of efficaciously decreasing the lung fungal burden, and continuous monitoring of BG is useful for the evaluation of therapeutic effect of antifungals. Infection of C. albicans with associated pathological damage implies the need for antifungal therapy.

The Establishment of Realtime Fluorescent Quantitative Polymerase chain reaction(PCR) for Detection of Highly Pathogenic Avian Influenza Virus Subtype H5N1

Highly pathogenic strains of avian influenza virus (AIV), which are influenza A viruses, cause severe disease in domestic poultry and humans. The objective of this study was to establish a fluorescent quantitative RT-PCR assay for detection of highly pathogenic avian influenza virus (AIV) subtype H5N1. The H5 and N1 subtypespecific probe sets were developed based on avian influenza virus sequences detected in China. Two pairs of primers and two fluorescent probes were strictly designed and optimized in a reaction system. According to the amount of plasmid RNA extracted from H5N1 strains, the standard curve DWQBGWDWQBGW of fluorescent quantitative PCR was drawn and all of the specimens were then tested by means of Real-time PCR. The test of highly pathogenic AIV subtype H5N1 was identified to be specific and its sensitivity level was 102~103 copies/reaction. The standard curve was accomplished at 109～105 DNA copies/reaction. It took only three hours from viral RNA extraction through to completion of the test. The assay was easy to carry out and highly reproducible. In conclusion, fluorescent quantitative PCR, described here, provides a rapid, specific and sensitive method to detect not only the H5 but N1 genes as well.