Periodontopathic bacterial endotoxin-induced tumor necrosis factor alpha production was inhibited by exercise in mice

Exhaustive exercise increases the TNF-α production in response to flagellin via the upregulation of toll-like receptor 5 in the large intestine in mice

Although intense exercise may induce temporary immune depression, it is unclear whether exercise stimulates tumor necrosis factor-alpha (TNF-α) production in response to flagella protein flagellin (FG), which binds to toll-like receptor 5 (TLR5) and induces the production of pro-inflammatory cytokines. Male C3H/HeN mice were administered FG (1mg/kg, i.v.) after exhaustive exercise (EX), and the plasma TNF-α concentrations were examined. The production of TNF-α and the TLR5 expression in both RAW264 and Caco2 cells were measured under FG conditions in vitro. Although the plasma TNF-α concentrations were observed to significantly increase in both the EX and non-EX (N-EX) mice (p<0.01, respectively) following FG injection, the TNF-α levels in the EX mice were significantly higher than those observed in the N-EX mice (p<0.01). Epinephrine (Ep) treatment accelerated the FG-induced TNF-α production and TLR5 expression on the Caco2, but not RAW264 cells. Interestingly, a high Ep-induced TLR5 expression was observed on the Caco2 cell surface, which was inhibited by an inhibitor of phosphoinositide3-kinase (PI3K), Ly294002, as well as a β-adrenergic blocker, propranolol. In addition, the EX-induced TNF-α production observed in response to FG was also attenuated by pretreatment with propranolol. Our findings suggest that exhaustive exercise upregulates the production of TNF-α in response to FG via a high expression of TLR5 on the intestinal cell surface following the stimulation of β-adrenergic receptors with exercise.

Exhaustive exercise reduces TNF-α and IFN-α production in response to R-848 via toll-like receptor 7 in mice

Stressful exercise results in temporary immune depression. However, the impact of exercise on the immune responses via toll-like receptor (TLR) 7, which recognizes the common viral genomic feature, single-stranded RNA, remains unclear. To clarify the effect of stressful exercise on immune function in response to viral infection, we measured the changes in the plasma concentration of tumor necrosis factor (TNF)-α and interferon (IFN)-α, which are induced downstream from the TLR–ligand interaction, in exhaustive-exercised mice immediately after treatment with the imidazoquinoline R-848, which can bind to and activate TLR7. Both exhaustive-exercised (EX) and non-exercised (N-EX) male C3H/HeN mice were injected with R-848 (5 mg kg⁻¹), and blood samples were collected. In addition, RAW264 cells, which are mouse macrophage cells, were cultured 30 min after epinephrine (10 μM) or norepinephrine (10 μM) treatments, and were then stimulated with R-848 (10 μg ml⁻¹). In addition, the effect of propranolol (10 mg kg⁻¹) as blockade of β-adrenergic receptors on R-848-induced TNF-α and IFN-α production in the exercised mice was examined. Both the TNF-α and IFN-α concentrations in the plasma of EX were significantly lower than those in the plasma of N-EX after R-848 injection (P < 0.05 and P < 0.01, respectively), although the R-848 treatment increased the plasma TNF-α and IFN-α concentrations in both groups (P < 0.01, respectively). The R-848-induced TNF-α production in RAW264 cells was significantly inhibited by epinephrine and norepinephrine pre-treatment, although IFN-α was not detected. The propranolol treatment completely inhibited exercise-induced TNF-α and IFN-α suppression in response to R-848 in the mice. These data suggest that EX induces a reduction in TNF-α and IFN-α production in response to R-848, and that these phenomena might be regulated by an exercise-induced elevation of the systemic catecholamines.

Effect of eel galectin AJL-1 on periodontopathic bacterial biofilm formation and their lipopolysaccharide-mediated inflammatory cytokine induction

Porphyromonas gingivalis, Prevotella intermedia and Aggregatibacter actinomycetemcomitans, infectious pathogenic bacteria found in oral biofilm, cause periodontal disease. The inhibitory effect of AJL-1, a galectin present in the skin mucus of the Japanese eel Anguilla japonica, on biofilm formation by each of these strains was investigated by staining adherent bacteria on culture plates with crystal violet. An ATP bioluminescence assay was used to determine whether inhibition of biofilm formation was due to the bactericidal activity of AJL-1. The effect of AJL-1 on cytokine induction in human umbilical vascular endothelial cells (HUVECs) by lipopolysaccharide (LPS) isolated from A. actinomycetemcomitans was also investigated by enzyme-linked immunosorbent assay (ELISA). AJL-1 significantly inhibited biofilm formation by A. actinomycetemcomitans strains Y4, ATCC 29523 and ATCC 29524 but not by any strain of P. gingivalis or P. intermedia, and showed no bactericidal activity against A. actinomycetemcomitans strains. AJL-1 markedly suppressed interleukin (IL)-6 and IL-8 induction in HUVECs by LPS from A. actinomycetemcomitans strains Y4 and ATCC 29523. These observations indicate that AJL-1 is an effective inhibitor of biofilm formation by A. actinomycetemcomitans as well as of inflammatory cytokine induction in HUVECs by LPS. These finding indicate that AJL-1 may be of therapeutic value in A. actinomycetemcomitans-associated periodontal diseases.

Type I NKT cells protect (and type II NKT cells suppress) the host's innate antitumor immune response to a B-cell lymphoma

Natural killer T (NKT) cells are a T-cell subpopulation known to possess immunoregulatory functions and recognize CD1d molecules. The majority of NKT cells express an invariant T-cell receptor (TCR) alpha chain rearrangement (Valpha14 Jalpha18 in mice; Valpha24 Jalpha18 in humans) and are called type I NKT cells; all other NKT cells are type II. In the current study, we have analyzed the roles for these NKT-cell subsets in the host's innate antitumor response against a murine B-cell lymphoma model in vivo. In tumor-bearing mice, we found that type I NKT cells conferred protection in a CD1d-dependent manner, whereas type II NKT cells exhibited inhibitory activity. Pro- and anti-inflammatory cytokines secreted by splenocytes from tumor-bearing mice correlated with tumor progression. Myeloid cells (CD11b(+)Gr1(+)) were present in large numbers at the tumor site and in the spleen of tumor-bearing type I NKT-deficient mice, suggesting that antitumor immunosurveillance was inhibited by CD11b(+)Gr1(+) cells. Overall, these data suggest that there are distinct roles for NKT-cell subsets in response to a B-cell lymphoma in vivo, pointing to potential novel targets to be exploited in immunotherapeutic approaches against blood cancers.