Toll-like receptor 4 (TLR4) is known to contribute to the modulation of insulin resistance and systemic inflammation seen in obesity and the metabolic syndrome. The present study was performed to investigate the fertility competence of TLR4 knock out male mice (TLR4 mice) on a high-fat diet (HFD), compared to a normal-chow diet (NCD). The controls included wildtype (WT) mice fed on a HFD or NCD. Six-week-old male mice were fed with either a NCD or HFD for 20 weeks. Body and organ weights, serum levels of glucose, triglycerides and hepatoxicity, sperm quality and spermatogenesis were observed after the sacrifice. Also, randomly selected male mice were mated with virgin female mice after feeding of 19 weeks. The weight of the body and organs increased in WT and TLR4 mice on a HFD compared to those of mice on a NCD. The weights of the reproductive organs did not vary among the treatment groups. The motility and concentration of the epididymal spermatozoa decreased in both WT and TLR4 mice fed a HFD. The pregnancy rate and litter size declined in the HFD-fed WT mice compared to the HFD-fed TLR4 mice. In conclusion, the HFD alters energy and steroid metabolism in mice, which may lead to male reproductive disorders. However, fertility competence was somewhat restored in HFD-fed TLR4 male mice, suggesting that the TLR4 is involved in testis dysfunction due to metabolic imbalance.

Aloe-emodin (AE) is the major bioactive component in aloe and known to exhibit anti-inflammatory activities. However, it has not been elucidated whether its anti-inflammatory potency can contribute to the elimination of obesity. The aim of the current study is to investigate the effect of AE on toll-like receptor 4 (TLR4) pathways in the presence of lipopolysaccharide (LPS) in 3T3-L1 adipocytes. 3T3-L1 adipocytes were treated with AE (0-20 μM) for one hour, followed by LPS treatment for 30 min and then, adipokine mRNA expression levels were measured. Next, TLR4-related molecules were measured in LPS-stimulated 3T3-L1 adipocytes. AE significantly decreased the mRNA expression of the tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and monocyte chemoattractant protein-1 (MCP-1) in a dose-dependent manner. Moreover, AE suppressed TLR4 mRNA expression. Further study showed that AE could suppress the nuclear factor-κB (NF-κB) and phosphorylation of extracellular receptor-activated kinase (pERK). The results of this study suggest that AE directly inhibits TLR4/NF-κB/ERK signaling pathways and decreases the inflammatory response in adipocytes.

The purpose of this study is to investigate the effects of arabinoxylan rice bran and endurance exercise training on TLR4 mediated protein expression in LPS-treated rats. The results showed that TLR4 as an important protein in the inflammatory response against lipopolysaccharide was shown to be significantly lower in both arabinoxylan supplement with exercise group and exercise group, thus the arabinoxylan rice bran had a higher inhibitory activity than arabinoxylan supplement group. However, NF-κB and MyD88 protein expression was not changed in arabinoxylan supplement with exercise training group, whereas NF-κB significantly decreased in 4 weeks of exercise training group. These results suggest that the supplement of arabinoxylan rice bran with exercise is likely to contribute to inflammation response and the arabinoxylan rice bran can be used as a possible safe alternative to the immunotherapeutic intervention.

Brucella spp. are facultative intracellular pathogens that have the ability to survive and multiply in professional and nonprofessional phagocytes and cause abortion in domestic animals and undulant fever in humans. Brucella species can survive in a variety of cells, including macrophages and their virulence and chronic infections are thought to be due to their ability to avoid the killing mechanisms within macrophages. Inhibition of phagosome-lysosome fusion has been proposed as a mechanism for intracellular survival of Brucella in professional and nonprofessional phagocytes. Toll-like receptors (TLRs) are part of a skillful system for detection of invasion by microbial pathogens. Recognition of microbial components by TLRs triggers signaling pathways that promote expression of genes and regulate innate immune responses. Recent studies for the interaction between TLRs-Brucella have indicated the importance of control of Brucella infection. Here, we review selected aspects of TLRs-Brucella interaction, which may be helpful to understanding the mechanism of Brucella pathogenesis.

Odontoblasts and/or dental pulp cells are responsible for tooth repair as well as dentin formation. Adhesion and migration are critical processes for tissue regeneration. This study was performed to clarify whether Pam3 modulates adhesion and migration of a murine odontoblast-like cell line, MDPC-23 cell and TLR2 signaling is engaged in this process. TLR2 expression in MDPC-23 cells was examined by RT-PCR. Adhesion assay was performed using type Ⅰ collagen-coated plates. Migration ability was determined by a commercial assay kit. Phosphorylation of IκB-α, JNK, p38, and ERK was examined by Western blot analysis. TLR2 was functionally expressed in MDPC-23 cells. Pam3CSK treatment enhanced adhesion and migration of MDPC-23 cells in a dose-dependent manner. Blockade of TLR2 using its antibody restored Pam3CSK-induced adhesion and migration of MDPC-23 cells. These findings indicate that Pam3CSK, an immune activator from gram negative bacteria, can promote adhesion and migration ability of MDPC-23 cells via TLR2.

Recently, as a natural substance has been emphasized interest in research to enhance the immune function. Green lettuce (Lactuca sativa L.) is a popular vegetable used fresh and it contains various phytochemicals and antioxidant compounds, and has been reported to have various physiological activities such as antibacterial, antioxidant, antitumor and anti-mutagenic. However, only a few studies have investigated on the mechanism of action of immune-enhancing activity of lettuce. Therefore, in this study, the immunomodulatory activities and potential mechanism of action of Green lettuce extracts (GLE) were evaluated in the murine macrophage cell line RAW264.7. GLE significantly increased NO levels by RAW264.7 cells, as well as expressions of immunomodulators such as iNOS, COX-2, IL-1β, IL-6, IL-12, TNF-α and MCP-1. Although GLE activated ERK1/2, p38, JNK and NF-κB, GLE-mediated expressions of immunomodulators was dependent on p38, JNK and NF-κB. In addition, TLR4 inhibition blocked GLE-mediated expressions of immunomodulators and activation of p38, JNK and NF-κB. Taken together, these results demonstrated that TLR4-MAPK/NF-κB signalling pathways participated in GLE-induced macrophage activation and GLE could be developed as a potential immunomodulating functional food.