<i>Mycobacterium tuberculosis</i>Interferes with the Response to Infection by Inducing the Host EphA2 Receptor

Khounlotham, Manirath; Subbian, Selvakumar; Smith, Roger; Cirillo, Suat L. G.; Cirillo, Jeffrey D.

doi:10.1086/599096

Cited by 20 publications

(16 citation statements)

References 41 publications

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“…Mtb strain CDC1551 was transformed with the vector pFJS8 that carries the L5 promoter expressing GFP (51). Flow cytometry was conducted essentially as described previously (52 β-Lactamase Activity Assays and Fractionation. Cultures of mycobacteria grown to early exponential phase (OD 600 = 0.4) and centrifuged for 10 min at 3,000 × g to separate the bacteria from the supernatant.…”

Section: Methodsmentioning

confidence: 99%

Imaging tuberculosis with endogenous β-lactamase reporter enzyme fluorescence in live mice

Kong

Yao

Ren

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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174

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The slow growth rate and genetic intractability of tubercle bacilli has hindered progress toward understanding tuberculosis, one of the most frequent causes of death worldwide. We overcame this roadblock through development of near-infrared (NIR) fluorogenic substrates for β-lactamase, an enzyme expressed by tubercle bacilli, but not by their eukaryotic hosts, to allow real-time imaging of pulmonary infections and rapid quantification of bacteria in living animals by a strategy called reporter enzyme fluorescence (REF). This strategy has a detection limit of 6 ± 2 × 10 2 colony-forming units (CFU) of bacteria with the NIR substrate CNIR5 in only 24 h of incubation in vitro, and as few as 10 4 CFU in the lungs of live mice. REF can also be used to differentiate infected from uninfected macrophages by using confocal microscopy and fluorescence activated cell sorting. Mycobacterium tuberculosis and the bacillus CalmetteGuérin can be tracked directly in the lungs of living mice without sacrificing the animals. Therapeutic efficacy can also be evaluated through loss of REF signal within 24 h posttreatment by using in vitro whole-bacteria assays directly in living mice. We expect that rapid quantification of bacteria within tissues of a living host and in the laboratory is potentially transformative for tuberculosis virulence studies, evaluation of therapeutics, and efficacy of vaccine candidates. This is a unique use of an endogenous bacterial enzyme probe to detect and image tubercle bacilli that demonstrates REF is likely to be useful for the study of many bacterial infections.infection | pulmonary | Mycobacterium | fluorogenic | beta-lactamase

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Section: Methodsmentioning

confidence: 99%

Imaging tuberculosis with endogenous β-lactamase reporter enzyme fluorescence in live mice

Kong

Yao

Ren

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

174

170

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“…This can be observed as decreased proportions of double-positive (CD4 ϩ CD8 ϩ ) cells in the thymus and reduced T lymphocytes in secondary lymphoid organs [25]. A recent study shows an accumulation of T cells and dendritic cells in lungs of EphA2 Ϫ/Ϫ mice infected with Mycobacterium tuberculosis, indicating a role played by EphA2 in modulating migration of these cells [26].…”

Section: Introductionmentioning

confidence: 99%

Activation of EphA receptors on CD4+CD45RO+ memory cells stimulates migration

Holen

Nustad

Aasheim

2010

Journal of Leukocyte Biology

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We have demonstrated previously that binding of ephrin-A1 to EphA receptors on human CD4(+) and CD8(+) T cells stimulates migration. Two EphA receptors have been reported in T cells: EphA1 at the protein level and EphA4 at the mRNA level. In this study, we wanted to investigate the expression profile of these receptors in T cell subpopulations and to test if expression differences would affect the potential of cells to migrate upon ephrin-A1 binding. We have generated an anti-EphA4 mAb for expression analysis. Our data show that functional EphA4 is expressed on the cell surface of CD4(+) and CD8(+) T cells. In addition, EphA4 receptor expression is induced after overnight incubation in serum-free medium, in particular, on CD4(+)CD45RO(+) T cells. Migration of CD4(+) T cells in response to ephrin-A1 is observed for memory cells (CD45RO(+)) and much weaker for naïve cells (CD45RA(+)). A signaling complex associated with the EphA4 receptor has also been isolated and includes EphA1, the Src family kinases Fyn and Lck, Slp76, and Vav1. To conclude, T cells express EphA1 and EphA4 receptors. Expression differences of EphA4 are observed in subpopulations of CD4(+) T cells. This is related to the cell migration potential after ephrin-A1 binding.

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“…Systemic LPS administration results in increased EphA2 expression in the liver, lungs, and brains of rats 11 , and M. tuberculosis infection stimulates both ephrinA1 and EphA2 expression in the mouse lung 12 . The ephrinA1 gene was originally identified as a TNFα-inducible immediate-early response gene in human umbilical vein endothelial cells (HUVEC), and TNFα-induced vascular tube formation requires EphA2-ephrinA1 interactions 13 .…”

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confidence: 99%

EphA2 Activation Promotes the Endothelial Cell Inflammatory Response

Funk

Yurdagul

Albert

et al. 2012

ATVB

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Objective Endothelial cell activation results in altered cell-cell interactions with adjacent endothelial cells and with infiltrating leukocytes. Eph receptors and their ephrin ligands regulate cell-cell interactions during tissue remodeling, and multiple proinflammatory mediators induce endothelial EphA receptor and ephrinA ligand expression. Therefore, we sought to elucidate the role of EphA receptors and ephrinA ligands in endothelial cell activation and atherosclerosis. Methods and Results qRT-PCR screening for EphA/ephrinA expression in atherosclerosis-prone macrovascular endothelium identified EphA2, EphA4, and ephrinA1 as the dominant isoforms. Endothelial activation with oxidized LDL (oxLDL) and proinflammatory cytokines induced EphA2 and ephrinA1 expression and sustained EphA2 activation, whereas EphA4 expression was unaffected. Atherosclerotic plaques from mice and humans show enhanced EphA2 and ephrinA1 expression colocalizing in the endothelial cell layer. EphA2 activation with recombinant Fc-ephrinA1 induces proinflammatory gene expression (ex. VCAM-1, E-Selectin) and stimulates monocyte adhesion, while inhibiting EphA2 (siRNA, pharmacological inhibitors) abrogated both ephrinA1-induced and oxLDL-induced VCAM-1 expression. Conclusions The current data suggest that enhanced EphA2 signaling during endothelial cell activation perpetuates proinflammatory gene expression. Coupled with EphA2 expression in mouse and human atherosclerotic plaques, these data implicate EphA2 as a novel proinflammatory mediator and potential regulator of atherosclerotic plaque development.

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Mycobacterium tuberculosisInterferes with the Response to Infection by Inducing the Host EphA2 Receptor

Cited by 20 publications

References 41 publications

Imaging tuberculosis with endogenous β-lactamase reporter enzyme fluorescence in live mice

Imaging tuberculosis with endogenous β-lactamase reporter enzyme fluorescence in live mice

Activation of EphA receptors on CD4+CD45RO+ memory cells stimulates migration

EphA2 Activation Promotes the Endothelial Cell Inflammatory Response

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