Toll-Like Receptor-7 Signaling Promotes Nonalcoholic Steatohepatitis by Inhibiting Regulatory T Cells in Mice.

Toll-like receptor 7 (TLR7) signaling regulates the production of type 1 interferons (IFNs) and proinflammatory cytokines, such as tumor necrosis factor (TNF)-α, implicated in the control of regulatory T (Treg) cell activity. However, the mechanistic interplay between TLR7 signaling and Treg cells in nonalcoholic steatohepatitis (NASH) has not been elucidated. Our aim was to clarify the role of TLR7 signaling in the pathogenesis of NASH. Steatohepatitis was induced in wild-type (WT), TLR7-deficient, IFN-α/ß receptor 1-deficient, and Treg cell-depleted mice. TLR7-deficient and IFN-α/ß receptor 1-deficient mice were more protective to steatohepatitis than WT mice. Of interest, both TNF-α and type 1 IFN promoted apoptosis of Treg cells involved in the prevention of NASH. Indeed, Treg cell-depleted mice had aggravated steatohepatitis compared with WT mice. Finally, treatment with immunoregulatory sequence 661, an antagonist of TLR7, efficiently ameliorated NASH in vivo. These results demonstrate that TLR7 signaling can induce TNF-α production in Kupffer cells and type I IFN production in dendritic cells. These cytokines subsequently induce hepatocyte death and inhibit Treg cells activities, leading to the progression of NASH. Thus, manipulating the TLR7-Treg cell axis might be used as a novel therapeutic strategy to treat NASH.

Chemoprevention of a flavonoid fraction from Rhus verniciflua Stokes on aflatoxin B1-induced hepatic damage in mice.

Since aflatoxin B(1) (AFB(1))-mediated hepatic damage is related to the production of AFB(1)-8,9-epoxide and reactive oxygen species, bioactive compounds having antioxidant potentials are suggested to be capable of reducing AFB(1)-induced toxicity. We previously purified a mixture of flavonoids that we named RCMF (Rhus verniciflua Stokes chloroform-methanol fraction), from a traditional Korean food additive and herbal medicine. RCMF exhibited various biological effects, including antioxidant and antitumor activities. In this study, we examined whether RCMF protects against AFB(1)-induced liver injury using in vitro and in vivo systems. Pretreatment of HepG2 cells with RCMF significantly reduced AFB(1)-stimulated production of ROS and malondialdehyde (MDA) to the control levels. RCMF also prevented the reduction in HepG2 cell viability caused by AFB(1). Oral administration of RCMF to mice significantly suppressed an AFB(1)-induced increase in serum levels of alanine aminotransferase, alkaline phosphatase and lactate dehydrogenase. It also prevented MDA formation and blocked decreases in glutathione levels and superoxide dismutase activities in the livers of AFB(1)-treated mice. In addition, RCMF supplementation prevented an AFB(1) -induced decrease in serum titers of IgA and IgG1. Collectively, these results suggest that RCMF attenuates AFB(1)-mediated damage to the liver, and that this effect is at least partially related to the restoration of antioxidant defense systems and an increase in AFB(1)-GSH conjugate formation.

Pain modality and spinal glia expression by streptozotocin induced diabetic peripheral neuropathy in rats.

Pain symptoms are a common complication of diabetic peripheral neuropathy or an inflammatory condition. In the most experiments, only one or two evident pain modalities are observed at diabetic peripheral neuropathy according to experimental conditions. Following diabetic peripheral neuropathy or inflammation, spinal glial activation may be considered as an important mediator in the development of pain. For this reason, the present study was aimed to address the induction of pain modalities and spinal glial expression after streptozotocin injection as compared with that of zymosan inflammation in the rat. Evaluation of pain behavior by either thermal or mechanical stimuli was performed at 3 weeks or 5 hours after either intravenous streptozotocin or zymosan. Degrees of pain were divided into 4 groups: severe, moderate, mild, and non-pain induction. On the mechanical allodynia test, zymosan evoked predominantly a severe type of pain, whereas streptozotocin induced a weak degree of pain (severe+moderate: 57.1%). Although zymosan did not evoke cold allodynia, streptozotocin evoked stronger pain behavior, compared with zymosan (severe+moderate: 50.0%). On the other hand, the high incidence of thermal hyperalgesia (severe+moderate: 90.0%) and mechanical hyperalgesia (severe+moderate: 85.7%) by streptozotocin was observed, as similar to that of zymosan. In the spinal cord, the increase of microglia and astrocyte was evident by streptozotocin, only microglia was activated by zymosan. Therefore, it is recommended that the selection of mechanical and thermal hyperalgesia is suitable for the evaluation of streptozotocin induced diabetic peripheral neuropathy. Moreover, spinal glial activation may be considered an important factor.

Generation of CD2(+)CD8(+) NK Cells from c-kit(+) Bone Marrow Cells in Porcine.

Natural killer (NK) cells provide one of the initial barriers of cellular host defense against pathogens, in particular intracellular pathogens. Because bone marrow-derived hematopoietic stem cells (HSCs), lymphoid protenitors, can give rise to NK cells, NK ontogeny has been considered to be exclusively lymphoid. Here, we show that porcine c-kit(+) bone marrow cells (c-kit(+) BM cells) develop into NK cells in vitro in the presence of various cytokines [interleukin (IL)-2, IL-7, IL-15, IL-21, stem cell factor (SCF), and fms-like tyrosine kinase-3 ligand (FLT3L)]. Adding hydrocortisone (HDC) and stromal cells greatly increases the frequency of c-kit(+) BM cells that give rise to CD2(+)CD8(+) NK cells. Also, intracellular levels of perforin, granzyme B, and NKG2D were determined by RT-PCR and western blotting analysis. It was found that of perforin, granzyme B, and NKG2D levels significantly were increased in cytokine-stimulated c-kit(+) BM cells than those of controls. And, we compared the ability of the cytotoxicity of CD2(+)CD8(+) NK cells differentiated by cytokines from c-kit(+) BM cells against K562 target cells for 28 days. Cytokines-induced NK cells as effector cells were incubated with K562 cells as target in a ratio of 100:1 for 4 h once a week. In results, CD2(+)CD8(+) NK cells induced by cytokines and stromal cells showed a significantly increased cytotoxicity 21 days later. Whereas, our results indicated that c-kit(+) BM cells not pretreated with cytokines have lower levels of cytotoxicity. Taken together, this study suggests that cytokines-induced NK cells from porcine c-kit(+) BM cells may be used as adoptive transfer therapy if the known obstacles to xenografting (e.g. immune and non-immune problems) were overcome in the future.

The Antinociceptive Effect of Sigma-1 Receptor Antagonist, BD1047, in a Capsaicin Induced Headache Model in Rats.

Intracranial headaches, including migraines, are mediated by nociceptive activation of the trigeminal nucleus caudalis (TNC), but the precise mechanisms are poorly understood. We previously demonstrated that selective blockage of spinal sigma-1 receptors (Sig-1R) produces a prominent antinociceptive effect in several types of pain models. This study evaluates whether the Sig-1R antagonist (BD1047) has an antinociceptive effect on capsaicin (a potent C-fiber activator) induced headache models in rats. Intracisternal infusion of capsaicin evoked pain behavior (face grooming), which was significantly attenuated by BD1047 pretreatment. BD1047 consistently reduced capsaicin-induced Fos-like immunoreactivity (Fos-LI), a neuronal activator, in the TNC in a dose-dependent manner. Moreover, capsaicin-induced phosphorylation of N-methyl-D-aspartate receptor subunit 1 was reversed by BD1047 pretreatment in the TNC. These results indicate that the Sig-1R antagonist has an inhibitory effect on nociceptive activation of the TNC in the capsaicin-induced headache animal model.

A survey of ectoparasite infestations in stray dogs of Gwang-ju City, Republic of Korea.

This study was designed to investigate the incidence of ectoparasite infestation among stray dogs in Gwang-ju City, Republic of Korea. A total of 103 stray dogs collected in the Animal Shelter of Gwang-ju City from November 2003 to August 2005 were investigated in this study. Ectoparasites of one or more genera were detected in 45.6% (47 / 103) of the dogs examined for dermatologic lesions and/or skin scrapings (from 3-5 affected areas). Otodectes cynotis was found to be the most frequent parasite (22.3%, 23 / 103), followed by Sarcoptes scabiei var canis (19.4%, 20 / 103), Ctenocephalides canis (6.8%, 7 / 103), Demodex canis (4.9%, 5 / 103), and Trichodectes canis (1.0%, 1 / 103). Monospecific infestation was found in 83.0% (39 / 47) of the affected dogs, whereas concurrent infestations with 2 or more ectoparasites per animal were found in 17.0% (8 / 47) of the affected dogs. Trichodectes canis is reported for the first time in the Republic of Korea. Dogs less than 1 yr old were more heavily infected than other age groups (66.7%), and small-sized dogs of less than 3 kg body weight were more heavily infected than larger dogs (41.7%).