Establishment of BALB/C mouse models of influenza A H1N1 aerosol inhalation.

Influenza A (H1N1) is a rapidly spreading acute respiratory illness that remains a worldwide burden on public health. To simulate natural infection routes, BALB/C mice were challenged with the H1N1 virus by aerosol and intranasal instillation routes. We compared the weight change and survival of the mice for 14 consecutive days after infection. The infected mice were euthanized at days 3, 5, 7, and 9 to perform necropsies, lung pathological analyses, viral titers measurement, and lung cytokines examination. The aerosol-treated mice showed clinical symptoms on day 4, obvious lung lesions on day 5, rapid weight loss on day 7, peak virus replication in the lungs on days 7 to 9, and bronchial epithelial hyperplasia on day 9. However, after intranasal instillation, the mice exhibited clinical signs on day 2, rapid weight loss and obvious lung lesions on day 3, and peak virus replication in the lungs on days 3 to 5; no bronchial epithelial hyperplasia was detected. High levels of proinflammatory cytokines and chemokines were detected in the lungs of infected mice by both two routes. Disease and lung lesion progressions were slower in the mice that inhaled H1N1-containing aerosols than in those treated by intranasal instillation, and lung lesions were homogeneous in the aerosol group and heterogeneous in the intranasal group. In this study, BALB/C mouse models of H1N1 virus aerosol inhalation were successfully established and compared with mouse models of intranasal inoculation, aerosol mouse models had an infection route and lung pathology characteristics that more closely resembled those observed in humans.

Emergence of an ancient and pathogenic mammarenavirus.

Emerging zoonoses of wildlife origin caused by previously unknown agents are one of the most important challenges for human health. The Qinghai-Tibet Plateau represents a unique ecological niche with diverse wildlife that harbours several human pathogens and numerous previously uncharacterized pathogens. In this study, we identified and characterized a novel arenavirus (namely, plateau pika virus, PPV) from plateau pikas (Ochotona curzoniae) on the Qinghai-Tibet Plateau by virome analysis. Isolated PPV strains could replicate in several mammalian cells. We further investigated PPV pathogenesis using animal models. PPV administered via an intraventricular route caused trembling and sudden death in IFNαßR-/- mice, and pathological inflammatory lesions in brain tissue were observed. According to a retrospective serological survey in the geographical region where PPV was isolated, PPV-specific IgG antibodies were detected in 8 (2.4%) of 335 outpatients with available sera. Phylogenetic analyses revealed that this virus was clearly separated from previously reported New and Old World mammarenaviruses. Under the co-speciation framework, the estimated divergence time of PPV was 77-88 million years ago (MYA), earlier than that of OW and NW mammarenaviruses (26-34 MYA).

Mechanism and therapeutic prospect of resveratrol combined with TRAIL in the treatment of renal cell carcinoma.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been reported to kill a wide variety of tumor cells with minimal effects on normal cell. However, renal cell carcinoma (RCC) cells 786-0 and OS-RC-2 were resistant to TRAIL. The present study examines the potential of combining polyphenolic compound resveratrol (RES) with TRAIL. We found that RES can sensitize RCC cells to TRAIL-induced death. Electron microscopy analyses showed that RES plus TRAIL can induce both autophagy and apoptosis in RCC cells. It was proved that the apoptosis is caspase-dependent and the activation of caspase-8, caspase-9, and caspase-3 was involved in this process. Besides, we also found that XIAP expression was significantly inhibited after RES plus TRAIL treatment in RCC cells. Furthermore, a fiber-modified replication-deficient adenovirus Ad5/35-TRAIL was generated to test the synergistic effect of RES and TRAIL in vivo. Our data demonstrated that RES plus Ad5/35-TRAIL significantly inhibited RCC xenograft growth in nude mice. These results suggest the possibility of a new combination therapeutic leading to the improvement of RCC treatment.

The characteristics of hDPP4 transgenic mice subjected to aerosol MERS coronavirus infection via an animal nose-only exposure device.

BACKGROUND: Middle East respiratory syndrome coronavirus (MERS-CoV), which is not fully understood in regard to certain transmission routes and pathogenesis and lacks specific therapeutics and vaccines, poses a global threat to public health. METHODS: To simulate the clinical aerosol transmission route, hDPP4 transgenic mice were infected with MERS-CoV by an animal nose-only exposure device and compared with instillation-inoculated mice. The challenged mice were observed for 14 consecutive days and necropsied on days 3, 5, 7, and 9 to analyze viral load, histopathology, viral antigen distribution, and cytokines in tissues. RESULTS: MERS-CoV aerosol-infected mice with an incubation period of 5-7 days showed weight loss on days 7-11, obvious lung lesions on day 7, high viral loads in the lungs on days 3-9 and in the brain on days 7-9, and 60% survival. MERS-CoV instillation-inoculated mice exhibited clinical signs on day 1, obvious lung lesions on days 3-5, continuous weight loss, 0% survival by day 5, and high viral loads in the lungs and brain on days 3-5. Viral antigen and high levels of proinflammatory cytokines and chemokines were detected in the aerosol and instillation groups. Disease, lung lesion, and viral replication progressions were slower in the MERS-CoV aerosol-infected mice than in the MERS-CoV instillation-inoculated mice. CONCLUSION: hDPP4 transgenic mice were successfully infected with MERS-CoV aerosols via an animal nose-only exposure device, and aerosol- and instillation-infected mice simulated the clinical symptoms of moderate diffuse interstitial pneumonia. However, the transgenic mice exposed to aerosol MERS-CoV developed disease and lung pathology progressions that more closely resembled those observed in humans.

Triple combinations of neuraminidase inhibitors, statins and fibrates benefit the survival of patients with lethal avian influenza pandemic.

The high mortality of highly pathogenic avian influenza A (H5N1) viruses infection in humans gives rise to considerable concern that it might someday cause another lethal pandemic. At present there is no other effective alternative besides the early and enough administration of neuraminidase inhibitors, which may be crucial for the patient management. However, its efficacy is sometimes limited because of the late administration in some patients especially the seriously ill ones and the continual occurrence of oseltamivir resistant A (H5N1) strains. The specific candidate vaccine are still under development and the practical value of passive immunization is hard to be widely applied because of the scarcity of convalescent human plasma, especially in the early stage of a serious and rapidly progressing pandemic. Statins and fibrates, both of which are used in clinical practice, have anti-inflammatory and immunomodulatory effects and other multiple biologic activities. So we hypothesized that the two immunomodulatory agents may exhibit synergistic effects when they were combined to neuraminidase inhibitors to treat the A (H5N1) viruses infections via inhibiting the production of either the early inflammatory mediators (e.g., many cytokine/chemokine) or the late mediator (e.g., High Mobility Group Box Protein 1), even showing the anti-viral activities with the prevention of the development of antiviral resistance. Therefore, the novel triple combinations may be an optimal management to confront the next lethal influenza pandemic on its very beginning.