Immune Response in Young Thoroughbred Racehorses under Training

Training has a great impact on the physiology of an athlete and, like all stressful stimuli, can trigger an innate immune response and inflammation, which is part of a wider coping strategy of the host to restore homeostasis. The Thoroughbred racehorse is a valid animal model to investigate these changes thanks to its homogeneous training and highly selected genetic background. The aim of this study was to investigate modifications of the innate immune response and inflammation in young untrained Thoroughbred racehorses during the first training season through haematological and molecular investigations. Twenty-nine Thoroughbred racehorses were followed during their incremental 3-month sprint exercise schedule. Blood collection was performed at time 0 (T0; before starting the intense training period), 30 days after T0 (T30), and 90 days after T0 (T90). Haematological parameters (red and white blood cells, haemoglobin, and platelets) were evaluated and haematocrit (HCT), mean corpuscular haemoglobin concentration (MCHC), and red cells width distribution + standard deviation (RDW-SD) were calculated. Moreover, via RT-qPCR, we investigated the expression of, Interleukin 1β (IL-1β), Interleukin 4 (IL-4) Interleukin 6 (IL-6), Interleukin 2 (IL-2), Interleukin 3 (IL-3), Interleukin 5 (IL-5) Interleukin 8 (IL-8), Trasformig Growth Factor β and α (TGF-β), Tumor necrosis factor α (TNF-α), and Interferon γ (IFN-γ)genes. Main corpuscular volume (MCV) showed a significant (p = 0.008) increase at T90. Main corpuscular haemoglobin (MCH) and haemoglobin concentration (MCHC) values were significantly augmented at both T30 (p < 0.001) and T90 (p < 0.001). Basophils were significant increased at T30 (p = 0.02) and eosinophils were significantly increased at T90 (p = 0.03). Significant differences in gene expression were found for all the genes under study, with the exception of IFN-γ and TNF-α. In particular, IL-2 (T30, p = 0.011; T90, p = 0.015), IL-4 (T30, p = 0.009; T90, p < 0.001), and IL-8 (T30, p < 0.001; T90, p < 0.001) genes were significantly upregulated at both T30 and T90 with respect to T0, TGF-β was intensely downregulated at T30 (p < 0.001), IL-5 gene expression was significantly decreased at T90 (p = 0.001), while IL-1β (p = 0.005) and IL-3 (p = 0.001) expression was strongly augmented at the same time. This study highlighted long-term adjustments of O2 transport capability that can be reasonably traced back to exercise adaptation. Moreover, the observed changes of granulocyte numbers and functions and inflammatory cytokine gene expression confirm a major role of the innate immune system in the response to the complex of stressful stimuli experienced during the training period.

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Transient membrane recruitment of IRAK-1 in response to LPS and IL-1β requires TNF R1

AJP Cell Physiology ◽

10.1152/ajpcell.00500.2007 ◽

2008 ◽

Vol 295 (2) ◽

pp. C313-C323 ◽

Cited By ~ 9

Author(s):

Angelia Lockett ◽

Mark G. Goebl ◽

Maureen A. Harrington

Keyword(s):

Gene Expression ◽

Immune Response ◽

Plasma Membrane ◽

Innate Immune Response ◽

Cellular Response ◽

Interleukin 1 ◽

Innate Immune ◽

Variable Response ◽

Membrane Recruitment ◽

Tnf Α

The transcription factor NF-κB is an essential regulator of the innate immune response that functions as the first line of defense against infections. Activation of the innate immune response by bacterial lipopolysaccharide (LPS) triggers production of tumor necrosis factor-α (TNF-α) followed by interleukin-1 (IL-1). The IL-1 receptor associated kinase-1 (IRAK-1) is an integral component of the LPS, TNF-α, and IL-1 signaling pathways that regulate NF-κB. Thus we hypothesized that IRAK-1 coordinates cellular NF-κB responses to LPS, TNF-α, and IL-1. In contrast to TNF-α where IRAK-1 subcellular localization does not change, treatment with LPS or IL-1 leads to a loss in cytoplasmic IRAK-1 with a coordinate increase in plasma membrane associated modified IRAK-1. In fibroblasts lacking the type 1 TNF-α receptor (TNF R1), IRAK-1 turnover is altered and modification of IRAK-1 in the plasma membrane is decreased in response to LPS and IL-1, respectively. When NF-κB controlled gene expression is measured, fibroblasts lacking TNF R1 are hyperresponsive to LPS, whereas a more variable response to IL-1 is seen. Further analysis of the LPS response revealed that plasma membrane-associated IRAK-1 is found in Toll 4, IL-1, and TNF R1-containing complexes. The data presented herein suggest a model whereby the TNF R1-IRAK-1 interaction integrates the cellular response to LPS, TNF-α, and IL-1, culminating in a cell poised to activate TNF-α-dependent NF-κB controlled gene expression. In the absence of TNF R1-dependent events, exposure to LPS or IL-1 leads to hyperactivation of the inflammatory response.

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Angiotensin II AT1 blockade reduces the lipopolysaccharide-induced innate immune response in rat spleen

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.90962.2008 ◽

2009 ◽

Vol 296 (5) ◽

pp. R1376-R1384 ◽

Cited By ~ 32

Author(s):

Enrique Sánchez-Lemus ◽

Julius Benicky ◽

Jaroslav Pavel ◽

Ignacio M. Larrayoz ◽

Jin Zhou ◽

...

Keyword(s):

Gene Expression ◽

Immune Response ◽

Inflammatory Response ◽

Protein Expression ◽

Innate Immune Response ◽

Innate Immune ◽

Bacterial Endotoxin ◽

Ang Ii ◽

Tnf Α ◽

Mrna And Protein Expression

ANG II AT1 receptor blockade reduces inflammation in hypertension. To determine whether ANG II AT1 receptor blockers (ARBs) influence the innate immune inflammatory response in normotensive rats, we studied rat plasma and spleen after a 3-day subcutaneous pretreatment with the ARB candesartan followed by a single dose of the bacterial endotoxin LPS (50 μg/kg ip). Peripheral administration of LPS to rodents produced a generalized inflammatory response with increased release of TNF-α, IL-1β, and IL-6 into the circulation. Candesartan pretreatment reduced the LPS-induced release of TNF-α, IL-1β, and IL-6 into the circulation. The red pulp of rat spleen expressed large numbers of AT1 receptors and the LPS receptors Toll-like receptor 4 and CD14. Candesartan administration significantly blocked AT1 receptors. The ARB reduced the LPS-induced upregulation of CD14 gene expression; expression of TNF-α and IL-6 mRNA and protein; expression of IL-1β and IκB-α mRNA; COX-2 mRNA and protein expression and PGE2 concentration; inducible nitric oxide synthase (iNOS) gene and protein expression and iNOS activity; and Nox2 gene expression and 8-isoprostane levels. In addition, candesartan reduced the CD14 protein expression in saline- and LPS-treated rats. Our results suggest that AT1 receptors are essential for the development of the full innate immune response to bacterial endotoxin. The ARB decreased the general peripheral inflammatory reaction to LPS and partially decreased the inflammatory response in the spleen. An unrestricted innate immune response to the bacterial endotoxin may have deleterious effects for the organism and may lead to development of chronic inflammatory disease. We postulate that ARBs may have therapeutic effects on inflammatory conditions.

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Cytokine-Induced Apoptosis of Human Natural Killer Cells Identifies a Novel Mechanism to Regulate the Innate Immune Response

Blood ◽

10.1182/blood.v89.3.910 ◽

1997 ◽

Vol 89 (3) ◽

pp. 910-918 ◽

Cited By ~ 101

Author(s):

Mary E. Ross ◽

Michael A. Caligiuri

Keyword(s):

Immune Response ◽

Nk Cells ◽

Natural Killer ◽

Innate Immune Response ◽

Cell Apoptosis ◽

Nk Cell ◽

Innate Immune ◽

Tnf Α ◽

Ifn Γ ◽

Induced Apoptosis

Abstract Interferon-γ (IFN-γ) is critical for an effective innate immune response against infection. A combination of interleukins (ILs) derived from activated T cells (IL-2) and monocytes (IL-12), or monocytes alone (IL-15 and IL-12), induces optimal production of IFN-γ from natural killer (NK) cells. The mechanism by which human NK cells downregulate their production of IFN-γ is unknown. Here we show that the same cytokines that induce human NK cell IFN-γ production subsequently induce apoptosis of the NK cells. Fas, bcl-2, or bax do not appear to be involved in this process. The mechanism of cytokine-induced apoptosis of human NK cells appears to involve NK cell production of tumor necrosis factor-α (TNF-α). Neutralization of TNF-α or inhibition of TNF-α binding to the p80 TNF-α receptor partially inhibited apoptosis. Transforming growth factor-β, which inhibits cytokine-induced NK cell production of IFN-γ and TNF-α, also decreased cytokine-induced NK cell apoptosis. Costimulation of a CD3−CD56+ NK leukemia cell line with IL-2 and IL-12 or IL-15 and IL-12 induced apoptosis in vitro, which increased when combined with a chemotherapeutic agent. In summary, costimulation of human NK cells via the IL-2 receptor and the IL-12 receptor induces significant IFN-γ production, followed by NK cell apoptosis and a decline in IFN-γ production. Hence, cytokines that activate this innate immune response may also serve to limit it via apoptosis. This novel observation may have implications for the regulation of the innate immune response during infection, the toxicity of combination cytokine therapy, and the treatment of NK cell leukemia.

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