The production of lipopolysaccharide (LPS)-free recombinant proteins from culture supernatants is of great interest to biomedical research and industry. Due to the LPS-free cell wall structure and the well-defined secretion factor B (SecB)-dependent secretion pathway, Gram-positive bacteria are a superior alternative to Escherichia coli expression systems. However, the lack of inducible expression systems for high yields has been a bottleneck.
View Article and Find Full Text PDFDiabetic foot ulcers (DFUs) are the most common complications of diabetes resulting from hyperglycemia leading to ischemic hypoxic tissue and nerve damage. is the most frequently isolated bacteria from DFUs and causes severe necrotic infections leading to amputations with a poor 5-year survival rate. However, very little is known about the mechanisms by which dominantly colonizes and causes severe disease in DFUs.
View Article and Find Full Text PDFStaphylococcal superantigens induce massive activation of T cells and inflammation, leading to toxic shock syndrome. Paradoxically, increasing evidence indicates that superantigens can also induce immunosuppression by promoting regulatory T cell (Treg) development. In this study, we demonstrate that stimulation strength plays a critical role in superantigen-mediated induction of immunosuppressive human CD4+CD25+FOXP3+ T cells.
View Article and Find Full Text PDFStreptococcus agalactiae, otherwise known as Group B Streptococcus (GBS), is an opportunistic pathogen that vaginally colonizes approximately one third of healthy women. During pregnancy, this can lead to infection, resulting in premature rupture of membranes, chorioamnionitis, and stillbirths. Furthermore, GBS causes serious infection in newborns, including sepsis, pneumonia, and meningitis.
View Article and Find Full Text PDFDiabetic foot ulcer (DFU) is the most common and costly sequela of diabetes mellitus, often leading to lower-extremity amputation with poor 5-year survival rates. Staphylococcus aureus is the most prevalent pathogen isolated from DFU, suggesting adaptation of S. aureus to the unique metabolic conditions of diabetes.
View Article and Find Full Text PDF(pneumococcus) is a normal colonizer of the human nasopharynx capable of causing serious invasive disease. Since colonization of the nasopharynx is a prerequisite for progression to invasive diseases, the development of future protein-based vaccines requires an understanding of the intimate interaction of bacterial adhesins with host receptors. In this study, we identified that pneumococcal surface adhesin A (PsaA), a highly conserved pneumococcal protein known to play an important role in colonization of pneumococcus, can interact with Annexin A2 (ANXA2) on Detroit 562 nasopharyngeal epithelial cells.
View Article and Find Full Text PDFIn addition to their role in regulating transport across the nuclear envelope, increasing evidence suggests nuclear pore complexes (NPCs) function in regulating gene expression. For example, the induction of certain genes (e.g.
View Article and Find Full Text PDFStreptococcus agalactiae (Group B Streptococcus, GBS) normally colonizes healthy adults but can cause invasive disease, such as meningitis, in the newborn. To gain access to the central nervous system, GBS must interact with and penetrate brain or meningeal blood vessels; however, the exact mechanisms are still being elucidated. Here, we investigate the contribution of BspC, an antigen I/II family adhesin, to the pathogenesis of GBS meningitis.
View Article and Find Full Text PDFSuperantigens (SAgs) represent a diverse family of bacterial toxins that induce Vβ-specific T cell proliferation associated with an array of important diseases in humans and animals, including mastitis of dairy cows. However, an understanding of the diversity and distribution of SAg genes among bovine strains and their role in the pathogenesis of mastitis is lacking. Population genomic analysis of 195 bovine isolates representing 57 unique sequence types revealed that strains encode 2 to 13 distinct SAgs and that the majority of isolates contain 5 or more SAg genes.
View Article and Find Full Text PDFSuperantigens (SAgs) produced by at high concentrations induce proliferation of T cells bearing specific TCR Vβ sequences and massive cytokinemia that cause toxic shock syndrome. However, the biological relevance of SAgs produced at very low concentrations during asymptomatic colonization or chronic infections is not understood. In this study, we demonstrate that suboptimal stimulation of human PBMCs with a low concentration (1 ng/ml) of staphylococcal enterotoxin C1, at which half-maximal T cell proliferation was observed, induced CD8CD25 T cells expressing markers related to regulatory T cells (Tregs), such as IFN-γ, IL-10, TGF-β, FOXP3, CD28, CTLA4, TNFR2, CD45RO, and HLA-DR.
View Article and Find Full Text PDFMany effects of the non-psychoactive cannabinoid, cannabidiol (CBD), have been described in immune responses induced by strong immunological stimuli. It has also been shown that CBD enhances IL-2 production in response to low-level T cell stimulation. Since IL-2, in combination with TGF-β1, are critical for Treg induction, we hypothesized that CBD would induce CD4CD25FOXP3 Tregs in response to low-level stimulation.
View Article and Find Full Text PDFUnlabelled: Enteroviruses proteolyze nuclear pore complex (NPC) proteins (Nups) during infection, leading to disruption of host nuclear transport pathways and alterations in nuclear permeability. To better understand how enteroviruses exert these effects on nuclear transport, the mechanisms and consequences of Nup98 proteolysis were examined. The results indicate that Nup98 is rapidly targeted for degradation following enterovirus infection and that this is mediated by the enterovirus 2A protease (2A(pro)).
View Article and Find Full Text PDFJ Biol Chem
September 2010
Previous work has shown that several nucleoporins, including Nup62 are degraded in cells infected with human rhinovirus (HRV) and poliovirus (PV) and that this contributes to the disruption of certain nuclear transport pathways. In this study, the mechanisms underlying proteolysis of Nup62 have been investigated. Analysis of Nup62 in lysates from HRV-infected cells revealed that Nup62 was cleaved at multiple sites during viral infection.
View Article and Find Full Text PDFStress granules are sites of mRNA storage formed in response to a variety of stresses, including viral infections. Here, the mechanisms and consequences of stress granule formation during poliovirus infection were examined. The results indicate that stress granules containing T-cell-restricted intracellular antigen 1 (TIA-1) and mRNA are stably constituted in infected cells despite lacking intact RasGAP SH3-domain binding protein 1 (G3BP) and eukaryotic initiation factor 4G.
View Article and Find Full Text PDFPoliovirus disrupts nucleocytoplasmic trafficking and results in the cleavage of two nuclear pore complex (NPC) proteins, Nup153 and Nup62. The NPC is a 125-MDa complex composed of multiple copies of 30 different proteins. Here we have extended the analysis of the NPC in infected cells by examining the status of Nup98, an interferon-induced NPC protein with a major role in mRNA export.
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