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The discovery of an emerging viral disease, severe fever with thrombocytopenia syndrome (SFTS), caused by SFTS virus (SFTSV), has prompted the need to understand pathogenesis of SFTSV. We are unique in establishing an infectious model of SFTS in C57/BL6 mice, resulting in hallmark symptoms of thrombocytopenia and leukocytopenia. Viral RNA and histopathological changes were identified in the spleen, liver, and kidney. However, viral replication was only found in the spleen, which suggested the spleen to be the principle target organ of SFTSV. Moreover, the number of macrophages and platelets were largely increased in the spleen, and SFTSV colocalized with platelets in cytoplasm of macrophages in the red pulp of the spleen. In vitro cellular assays further revealed that SFTSV adhered to mouse platelets and facilitated the phagocytosis of platelets by mouse primary macrophages, which in combination with in vivo findings, suggests that SFTSV-induced thrombocytopenia is caused by clearance of circulating virus-bound platelets by splenic macrophages. Thus, this study has elucidated the pathogenic mechanisms of thrombocytopenia in a mouse model resembling human SFTS disease.animal model | phlebovirus | pathology | reduction of platelets | macrophage infection S evere fever with thrombocytopenia syndrome (SFTS) is a recently identified emerging viral infectious disease in China that is caused by a novel phlebovirus in the family Bunyaviridae, SFTS virus (SFTSV) (1). Clinical features of SFTS patients include abrupt high fever, thrombocytopenia, leukocytopenia, and gastrointestinal symptoms. Laboratory tests commonly show elevated serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), lactate dehydrogenase, creatine kinase, creatine kinase MB fraction, as well as elongated activated partial-thromboplastin time (1). These abnormally changed laboratory parameters are indicative of the pathological lesions that occur in multiple organs and altered homeostasis of the coagulation systems of SFTS patients. Pathological studies of SFTS are absent because patient tissues are rarely donated after death in rural areas of China. Therefore, the causes of illness and death, as well as pathological changes within organs, remain unclear. To systematically investigate the pathogenic mechanisms of SFTS and understand key symptoms, such as thrombocytopenia, infectious animal models for SFTSV are urgently needed. ResultsEstablishment of a SFTSV Pathogenic Mouse Model. In our initial study, to identify an infectious animal model that could mimic most clinical features during SFTSV infection, the susceptibilities of three commonly used laboratory rodent strains for phlebovirus (2-4), C57/BL6 mice, BalB/C mice, and Syrian hamsters, were examined. The SFTSV strain HB29 was inoculated at 10 5 TCID 50 (50% tissue culture infective dose) per mouse or 5 × 10 5 TCID 50 per hamster through four different routes of infection, including intravenous, intramuscular, intraperitoneal, and intracerebral...

Bacterial infection of the lung is associated with mucin overproduction. In partial explanation of this phenomenon, we recently reported that supernatant from the Gram-negative organism Pseudomonas (P.) aeruginosa contained an activity that upregulated transcription of the MUC 2 mucin gene [J.-D. Li, A. Dohrman, M. Gallup, S. Miyata, J. Gum, Y. Kim, J. Nadel, A. Prince, C. Basbaum, Transcriptional activation of mucin by P. aeruginosa lipopolysaccharide in the pathogenesis of cystic fibrosis lung disease, Proc. Natl. Acad. Sci. U.S.A., 94 (1997) 967-972]. The purpose of the present study was to determine whether mucin genes other than MUC 2 are so regulated and whether Gram-positive organisms also contain mucin stimulatory activity. Results from in situ hybridization and RNase protection assays showed that P. aeruginosa upregulates MUC 5AC as well as MUC 2 in both bronchial explants and cultured airway epithelial cells. The upregulation of both genes by P. aeruginosa can be mimicked by lipopolysaccharide (LPS) and can be blocked by the tyrosine kinase inhibitor genistein. In addition, both genes are upregulated by a variety of Gram-positive as well as Gram-negative organisms showing the same rank order of potency. These data indicate the existence of a general mechanism by which epithelial cells respond to the presence of bacteria by increasing mucin synthesis.

Background: COVID-19 (coronavirus disease 2019) has caused a major epidemic worldwide; however, much is yet to be known about the epidemiology and evolution of the virus partly due to the scarcity of full-length SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) genomes reported. One reason is that the challenges underneath sequencing SARS-CoV-2 directly from clinical samples have not been completely tackled, i.e., sequencing samples with low viral load often results in insufficient viral reads for analyses. Methods: We applied a novel multiplex PCR amplicon (amplicon)-based and hybrid capture (capture)-based sequencing, as well as ultra-high-throughput metatranscriptomic (meta) sequencing in retrieving complete genomes, inter-individual and intra-individual variations of SARS-CoV-2 from serials dilutions of a cultured isolate, and eight clinical samples covering a range of sample types and viral loads. We also examined and compared the sensitivity, accuracy, and other characteristics of these approaches in a comprehensive manner.

EMMPRIN (extracellular matrix metalloproteinase inducer) stimulates fibroblast metalloproteinases (MMP) 1, 2 and 3 (Kataoka et al. (1993) Cancer Res. 53, 3154^3158). Here we focus on MMP-1, showing that in lung tumors, MMP-1's cognate mRNA is strongly expressed in stromal fibroblasts adjacent to EMMPRIN-expressing tumor cells. In vitro, EMMPRIN upregulates MMP-1 mRNA expression in a concentration-dependent manner, with a peak accumulation at 24 h. The response is genistein-sensitive, suggesting it is dependent on tyrosine kinase activity. Analysis of tyrosine phosphorylation-dependent MAP kinases ERK 1/2, SAPK/JNK, and p38 showed that the activity of p38 but not that of the other 2 kinases was elevated in response to EMMPRIN. That p38 activity was required for EMMPRIN stimulation of MMP-1 was evident from results showing that the p38 inhibitor SB203580 blocked this response. This is the first available information regarding the mechanism by which tumor-associated molecules upregulate MMP synthesis in stromal fibroblasts.z 1998 Federation of European Biochemical Societies.

BackgroundLegionella pneumophila is the causative agent of human Legionnaire's disease. During infection, the bacterium invades macrophages and lung epithelial cells, and replicates intracellularly. However, little is known about its interaction with T cells. We investigated the ability of L. pneumophila to infect and stimulate the production of interleukin-8 (IL-8) in T cells. The objective of this study was to assess whether L. pneumophila interferes with the immune system by interacting and infecting T cells.ResultsWild-type L. pneumophila and flagellin-deficient Legionella, but not L. pneumophila lacking a functional type IV secretion system Dot/Icm, replicated in T cells. On the other hand, wild-type L. pneumophila and Dot/Icm-deficient Legionella, but not flagellin-deficient Legionella or heat-killed Legionella induced IL-8 expression. L. pneumophila activated an IL-8 promoter through the NF-κB and AP-1 binding regions. Wild-type L. pneumophila but not flagellin-deficient Legionella activated NF-κB, p38 mitogen-activated protein kinase (MAPK), Jun N-terminal kinase (JNK), and transforming growth factor β-associated kinase 1 (TAK1). Transfection of dominant negative mutants of IκBα, IκB kinase, NF-κB-inducing kinase, TAK1, MyD88, and p38 MAPK inhibited L. pneumophila-induced IL-8 activation. Inhibitors of NF-κB, p38 MAPK, and JNK blocked L. pneumophila-induced IL-8 expression. In addition, c-Jun, JunD, cyclic AMP response element binding protein, and activating transcription factor 1, which are substrates of p38 MAPK and JNK, bound to the AP-1 site of the IL-8 promoter.ConclusionsTaken together, L. pneumophila induced a flagellin-dependent activation of TAK1, p38 MAPK, and JNK, as well as NF-κB and AP-1, which resulted in IL-8 production in human T cells, presumably contributing to the immune response in Legionnaire's disease.

This study examines investor herding behavior in Pacific-Basin equity markets. Results indicate that the level of herding is time-varying, and is present in both rising and falling markets. It is positively related to stock market performance, but negatively related to market volatility. Herding estimates across markets are positively correlated, signifying comovement of herding behavior in the region. The findings suggest that tests for herding should consider its dynamic behavior.

With the advances in micro-electronics, wireless sensor devices have been made much smaller and more integrated, and large-scale wireless sensor networks (WSNs) based the cooperation among the significant amount of nodes have become a hot topic. “Large-scale” means mainly large area or high density of a network. Accordingly the routing protocols must scale well to the network scope extension and node density increases. A sensor node is normally energy-limited and cannot be recharged, and thus its energy consumption has a quite significant effect on the scalability of the protocol. To the best of our knowledge, currently the mainstream methods to solve the energy problem in large-scale WSNs are the hierarchical routing protocols. In a hierarchical routing protocol, all the nodes are divided into several groups with different assignment levels. The nodes within the high level are responsible for data aggregation and management work, and the low level nodes for sensing their surroundings and collecting information. The hierarchical routing protocols are proved to be more energy-efficient than flat ones in which all the nodes play the same role, especially in terms of the data aggregation and the flooding of the control packets. With focus on the hierarchical structure, in this paper we provide an insight into routing protocols designed specifically for large-scale WSNs. According to the different objectives, the protocols are generally classified based on different criteria such as control overhead reduction, energy consumption mitigation and energy balance. In order to gain a comprehensive understanding of each protocol, we highlight their innovative ideas, describe the underlying principles in detail and analyze their advantages and disadvantages. Moreover a comparison of each routing protocol is conducted to demonstrate the differences between the protocols in terms of message complexity, memory requirements, localization, data aggregation, clustering manner and other metrics. Finally some open issues in routing protocol design in large-scale wireless sensor networks and conclusions are proposed.