Protein kinase E of Mycobacterium tuberculosis has a role in the nitric oxide stress response and apoptosis in a human macrophage model of infection

ABSTRACT The ability of the fungal pathogen Cryptococcus neoformans to evade the mammalian innate immune response and cause disease is partially due to its ability to respond to and survive nitrosative stress. In this study, we use proteomic and genomic approaches to elucidate the response of C. neoformans to nitric oxide stress. This nitrosative stress response involves both transcriptional, translational, and posttranslational regulation. Proteomic and genomic analyses reveal changes in expression of stress response genes. In addition, genes involved in cell wall organization, respiration, signal transduction, transport, transcriptional control, and metabolism show altered expression under nitrosative conditions. Posttranslational modifications of transaldolase (Tal1), aconitase (Aco1), and the thiol peroxidase, Tsa1, are regulated during nitrosative stress. One stress-related protein up-regulated in the presence of nitric oxide stress is glutathione reductase (Glr1). To further investigate its functional role during nitrosative stress, a deletion mutant was generated. We show that this glr1Δ mutant is sensitive to nitrosative stress and macrophage killing in addition to being avirulent in mice. These studies define the response to nitrosative stress in this important fungal pathogen.

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Regulation of Cytokine and Chemokine Expression by the Ribotoxic Stress Response Elicited by Shiga Toxin Type 1 in Human Macrophage-Like THP-1 Cells

Infection and Immunity ◽

10.1128/iai.06025-11 ◽

2012 ◽

Vol 80 (6) ◽

pp. 2109-2120 ◽

Cited By ~ 20

Author(s):

Dinorah Leyva-Illades ◽

Rama P. Cherla ◽

Moo-Seung Lee ◽

Vernon L. Tesh

Keyword(s):

Stress Response ◽

Protein Kinase ◽

Shiga Toxin ◽

Mapk Signaling ◽

Human Macrophage ◽

28S Rrna ◽

Chemokine Production ◽

Content Type ◽

Chemokine Expression ◽

Ribotoxic Stress Response

ABSTRACTShiga toxins (Stxs) are cytotoxins produced by the enteric pathogensShigella dysenteriaeserotype 1 and Shiga toxin-producingEscherichia coli(STEC). Stxs bind to a membrane glycolipid receptor, enter cells, and undergo retrograde transport to ultimately reach the cytosol, where the toxins exert their protein synthesis-inhibitory activity by depurination of a single adenine residue from the 28S rRNA component of eukaryotic ribosomes. The depurination reaction activates the ribotoxic stress response, leading to signaling via the mitogen-activated protein kinase (MAPK) pathways (Jun N-terminal protein kinase [JNK], p38, and extracellular signal-regulated kinase [ERK]) in human epithelial, endothelial, and myeloid cells. We previously showed that treatment of human macrophage-like THP-1 cells with Stxs resulted in increased cytokine and chemokine expression. In the present study, we show that individual inactivation of ERK, JNK, and p38 MAPKs using pharmacological inhibitors in the presence of Stx1 resulted in differential regulation of the cytokines tumor necrosis factor alpha and interleukin-1β (IL-1β) and chemokines IL-8, growth-regulated protein-β, macrophage inflammatory protein-1α (MIP-1α), and MIP-1β. THP-1 cells exposed to Stx1 upregulate the expression of select dual-specificity phosphatases (DUSPs), enzymes that dephosphorylate and inactivate MAPKs in mammalian cells. In this study, we confirmed DUSP1 protein production by THP-1 cells treated with Stx1. DUSP1 inhibition by triptolide showed that ERK and p38 phosphorylation is regulated by DUSP1, while JNK phosphorylation is not. Inhibition of p38 MAPK signaling blocked the ability of Stx1 to induce DUSP1 mRNA expression, suggesting that an autoregulatory signaling loop may be activated by Stxs. Thus, Stxs appear to be capable of eliciting signals which both activate and deactivate signaling for increased cytokine/chemokine production in human macrophage-like cells.

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Regulation of the SigH stress response regulon by an essential protein kinase in Mycobacterium tuberculosis

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0801143105 ◽

2008 ◽

Vol 105 (35) ◽

pp. 13105-13110 ◽

Cited By ~ 65

Author(s):

S. T. Park ◽

C.-M. Kang ◽

R. N. Husson

Keyword(s):

Mycobacterium Tuberculosis ◽

Stress Response ◽

Protein Kinase ◽

Essential Protein

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1,25-Dihydroxyvitamin D3 Induces Nitric Oxide Synthase and Suppresses Growth of Mycobacterium tuberculosis in a Human Macrophage-Like Cell Line

Infection and Immunity ◽

10.1128/iai.66.11.5314-5321.1998 ◽

1998 ◽

Vol 66 (11) ◽

pp. 5314-5321 ◽

Cited By ~ 189

Author(s):

Kirk A. Rockett ◽

Roger Brookes ◽

Irina Udalova ◽

Vincent Vidal ◽

Adrian V. S. Hill ◽

...

Keyword(s):

Nitric Oxide ◽

Mycobacterium Tuberculosis ◽

Nitric Oxide Synthase ◽

Cell Line ◽

Host Defense ◽

Kinetic Studies ◽

Human Macrophage ◽

No Production ◽

Mrna Levels ◽

Oxide Synthase

ABSTRACT Inducible synthesis of nitric oxide (NO) by macrophages is an important mechanism of the host defense against intracellular infection in mice, but the evidence for significant levels of inducible NO production by human macrophages is controversial. Here we report that the human promyelocytic cell line HL-60, when differentiated to a macrophage-like phenotype, acquires the ability to produce substantial amounts of NO on stimulation with LPS or 1,25-dihydroxyvitamin D3 (1,25-D3) in the absence of activating factors such as gamma interferon. Expression of the inducible nitric oxide synthase (NOS2) was confirmed by sequencing of the reverse transcription-PCR product from stimulated HL-60 cells. Kinetic studies after lipopolysaccharide stimulation show that NOS2 mRNA levels rise within 3 to 6 h, that conversion of [14C]arginine to [14C]citrulline is maximal at 5 to 6 days, and that levels of reactive nitrogen intermediates stabilize at around 20 μM at 7 to 8 days. We find that 1,25-D3 acts to suppress the growth of Mycobacterium tuberculosis in these cells and that this effect is inhibited byN G-monomethyl-l-arginine, suggesting that vitamin D-induced NO production may play a role in the host defense against human tuberculosis.

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