Transcriptional responses in spleens from mice exposed to Yersinia pestis CO92

Immunohistochemical localization of nerve injury-induced protein-1 in mouse tissues

Nerve injury-induced protein (Ninjurin)-1 is a cell adhesion molecule that is upregulated in neurons and Schwann cells after transection injury in rats. In this study, we investigated the localization of Ninjurin-1 in various tissues, including the cerebrum, sciatic nerve, spleen, lung, stomach, ileum, colon, liver, pancreas, kidney, testis, and skin in C57BL/6 mice, using Western blotting and immunohistochemistry. Western blot analysis showed that Ninjurin-1 was differentially expressed among organs. Ninjurin-1 was abundant in skin and ileum, weakly expressed in cerebrum, and moderately expressed in the other organs studied. Immunohistochemical analysis largely confirmed the results of the western blot analysis with often localization of Ninjurin-1 in the regions with abundant connective tissues. In addition, Ninjurin-1 was differentially expressed in various cell types in the tissues under the investigation. These findings suggest that Ninjurin-1 may play organ-specific roles in development and homeostasis of many organs.

Yersinia pestis in the Age of Big Data

As omics-driven technologies developed rapidly, genomics, transcriptomics, proteomics, metabolomics and other omics-based data have been accumulated in unprecedented speed. Omics-driven big data in biology have changed our way of research. "Big science" has promoted our understanding of biology in a holistic overview that is impossibly achieved by traditional hypothesis-driven research. In this chapter, we gave an overview of omics-driven research on Y. pestis, provided a way of thinking on Yersinia pestis research in the age of big data, and made some suggestions to integrate omics-based data for systems understanding of Y. pestis.

Transcriptomic response to Yersinia pestis: RIG-I like receptor signaling response is detrimental to the host against plague

Bacterial pathogens have evolved various mechanisms to modulate host immune responses for successful infection. In this study, RNA-sequencing technology was used to analyze the responses of human monocytes THP1 to Yersinia pestis infection. Over 6000 genes were differentially expressed over the 12 h infection. Kinetic responses of pathogen recognition receptor signaling pathways, apoptosis, antigen processing, and presentation pathway and coagulation system were analyzed in detail. Among them, RIG-I-like receptor (RLR) signaling pathway, which was established for antiviral defense, was significantly affected. Mice lacking MAVS, the adaptor of the RLR signaling pathway, were less sensitive to infection and exhibited lower IFN-β production, higher Th1-type cytokines IFN-γ and IL-12 production, and lower Th2-type cytokines IL-4 and IL-13 production in the serum compared with wild-type mice. Moreover, infection of pathogenic bacteria other than Y. pestis also altered the expression of the RLR pathway, suggesting that the response of RLR pathway to bacterial infection is a universal mechanism.

Omics strategies for revealing Yersinia pestis virulence

Omics has remarkably changed the way we investigate and understand life. Omics differs from traditional hypothesis-driven research because it is a discovery-driven approach. Mass datasets produced from omics-based studies require experts from different fields to reveal the salient features behind these data. In this review, we summarize omics-driven studies to reveal the virulence features of Yersinia pestis through genomics, trascriptomics, proteomics, interactomics, etc. These studies serve as foundations for further hypothesis-driven research and help us gain insight into Y. pestis pathogenesis.

IQGAP1 in microbial pathogenesis: Targeting the actin cytoskeleton

Microbial pathogens cause widespread morbidity and mortality. Central to the pathogens' virulence is manipulation of the host cell's cytoskeleton, which facilitates microbial invasion, multiplication, and avoidance of the innate immune response. IQGAP1 is a ubiquitously expressed scaffold protein that integrates diverse signaling cascades. Research has shown that IQGAP1 binds to and modulates the activity of multiple proteins that participate in bacterial invasion. Here, we review data that support a role for IQGAP1 in infectious disease via its ability to regulate the actin cytoskeleton. In addition, we explore other mechanisms by which IQGAP1 may be exploited by microbial pathogens.

Time-dose-response models for microbial risk assessment

While microbial risk assessment (MRA) has been used for over 25 years, traditional dose-response analysis has only predicted the overall risk of adverse consequences from exposure to a given dose. An important issue for consequence assessment from bioterrorist and other microbiological exposure is the distribution of cases over time due to the initial exposure. In this study, the classical exponential and beta-Poisson dose-response models were modified to include exponential-power dependency of time post inoculation (TPI) or its simplified form, exponential-reciprocal dependency of TPI, to quantify the time of onset of an effect presumably associated with the kinetics of in vivo bacterial growth. Using the maximum likelihood estimation approach, the resulting time-dose-response models were found capable of providing statistically acceptable fits to all tested pooled animal survival dose-response data. These new models can consequently describe the development of animal infectious response over time and represent observed responses fairly accurately. This is the first study showing that a time-dose-response model can be developed for describing infections initiated by various pathogens. It provides an advanced approach for future MRA frameworks.

Vapour-phase hydrogen peroxide inactivates Yersinia pestis dried on polymers, steel, and glass surfaces

AIMS

This study evaluated the inactivation of virulent Yersinia pestis dried on polymers, steel, and glass surfaces using vapour-phase hydrogen peroxide.

METHODS AND RESULTS

A suspension of Y. pestis CO92 (1.70 x 10(8) CFU) was dried on 10 different types of test surfaces and exposed to vapour-phase hydrogen peroxide fumigation for a contact time of 2 h. A significant reduction in the log10 CFU of Y. pestis on all 10 materials was observed between the controls evaluated after a 1 h drying time and unexposed controls evaluated after the decontamination run. Qualitative growth assessment showed that vapour-phase hydrogen peroxide exposure inactivated Y. pestis on all replicates of the 10 test materials as well as biological indicators up to 7 days postexposure.

CONCLUSIONS

Virulent Y. pestis CO92 is inactivated on polymers, steel, and glass surfaces when exposed to vapour-phase hydrogen peroxide without observable physical damage to the test materials.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides information for using vapour-phase hydrogen peroxide as a practical process for the decontamination of virulent Y. pestis in circumstances where time-dependent attenuation/inactivation orliquid/heat decontamination may not be the most suitable approach.