Host T cells are the main producers of IL-17 within the central nervous system during initiation of experimental autoimmune encephalomyelitis induced by adoptive transfer of Th1 cell lines

Experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis, has long been thought to be mediated by Th1 CD4(+) T cells. Using adoptive transfer techniques, transfer of CNS specific Th1 T cells was sufficient to induce EAE in naive mice. However, recent studies found a vital role for IL-17 in induction of EAE. These studies suggested that a fraction of IL-17-producing T cells that contaminate Th1 polarized cell lines are largely responsible for initiation of EAE. In this study, we tracked the appearance and cytokine production capacity of adoptively transferred cells within the CNS of mice throughout EAE disease. IL-17-producing, adoptively transferred cells were not enriched over the low percentages present in vitro. Thus, there was no selective recruitment and/or preferential proliferation of adoptively transferred IL-17-producing cells during the induction of EAE. Instead a large number of CNS infiltrating host T cells in mice with EAE were capable of producing IL-17 following ex vivo stimulation. The IL-17-producing T cells contained both alphabeta and gammadelta TCR(+) T cells with a CD4(+)CD8(-) or CD4(-)CD8(-) phenotype. These cells concentrated within the CNS within 3 days of adoptive transfer, and appeared to play a role in EAE induction as adoptive transfer of Th1 lines derived from wild-type mice into IL-17-deficient mice induced reduced EAE clinical outcomes. This study demonstrates that an encephalitogenic Th1 cell line induces recruitment of host IL-17-producing T cells to the CNS during the initiation of EAE and that these cells contribute to the incidence and severity of disease.     

Local and chemical distribution of phlorotannins in brown algae

The local and chemical distribution of phlorotannins among the Japanese Laminariaceae, Eisenia bicyclis, Ecklonia cava and Ecklonia kurome, was investigated. As a result of light microscopy observations with vanillin-HCl staining, phlorotannins were found to be accumulated within the vegetative cells of the outer cortical layer of the thalli, regardless of the species, stage of growth or organ. Crude phlorotannins comprised about 3.0% of the algal powder for each of the algae. High-performance liquid chromatography (HPLC) showed that the phlorotannins of E. bicyclis were composed of phloroglucinol (0.9%), phloroglucinol tetramer (4.4%), eckol (7.5%), phlorofucofuroeckol A (21.9%), dieckol (23.4%), and 8,8'-bieckol (24.6%), plus some other unknown phenolic compounds (17.3%). The composition of the phlorotannins differed little among the Laminariaceae, except for a significantly larger amount of the tetramer, MW 478, in E. bicyclis.     

MRI-Based Analysis of Intracerebral Hemorrhage in Mice Reveals Relationship between Hematoma Expansion and the Severity of Symptoms

Intracerebral hemorrhage (ICH) is featured by poor prognosis such as high mortality rate and severe neurological dysfunction. In humans, several valuables including hematoma volume and ventricular expansion of hemorrhage are known to correlate with the extent of mortality and neurological dysfunction. However, relationship between hematoma conditions and the severity of symptoms in animal ICH models has not been clarified. Here we addressed this issue by using 7-tesla magnetic resonance imaging (MRI) on collagenase-induced ICH model in mice. We found that the mortality rate and the performance in behavioral tests did not correlate well with the volume of hematoma. In contrast, when hemorrhage invaded the internal capsule, mice exhibited high mortality and showed poor sensorimotor performance. High mortality rate and poor performance in behavioral tests were also observed when hemorrhage invaded the lateral ventricle, although worsened symptoms associated with ventricular hemorrhage were apparent only during early phase of the disease. These results clearly indicate that invasion of the internal capsule or the lateral ventricle by hematoma is a critical determinant of poor prognosis in experimental ICH model in mice as well as in human ICH patients. MRI assessment may be a powerful tool to refine investigations of pathogenic mechanisms and evaluations of drug effects in animal models of ICH.     

A Sialylated Voltage-Dependent Ca2+ Channel Binds Hemagglutinin and Mediates Influenza A Virus Entry into Mammalian Cells

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Transgenic expression of osteoactivin in the liver attenuates hepatic fibrosis in rats

The role of osteoactivin (OA) in liver fibrogenesis remains unclear. After feeding wild-type (WT) and OA transgenic (OA-Tg) rats a choline-deficient, L-amino acid-defined (CDAA) diet for 12 weeks, we evaluated liver fibrosis. Hepatic fibrosis and expression of alpha-smooth muscle actin protein in OA-Tg rats were reduced in comparison to WT rats. Our examination of the expression of 31,100 genes by microarray analysis identified 177 and 256 genes that were upregulated and downregulated, respectively, by at least twofold in OA-Tg rat livers in comparison to WT rat livers. Of these genes, we confirmed a significant downregulation in the expression levels of tissue inhibitor of metalloproteinase-1 and -2, type I collagen, and platelet-derived growth factor receptor-alpha and -beta in the livers of OA-Tg rats. These results indicate that transgenic OA expression attenuates the development of hepatic fibrosis in association with the suppression of specific genes involved in its pathogenesis.     

Characterization of a novel oncogenic K-ras mutation in colon cancer

Activating mutations of RAS are frequently observed in subsets of human cancers, indicating that RAS activation is involved in tumorigenesis. Here, we identified and characterized a novel G to T transversion mutation of the K-ras gene at the third position of codon 19 (TTG) which substituted phenylalanine for leucine in 3 primary colon carcinomas. Biological and biochemical activity was examined using transformed NIH3T3 cells expressing mutant or wild-type K-ras. Transformants harboring the K-ras mutation at codon 19 showed proliferative capacity under serum-starved conditions, less contact inhibition, anchorage-independent growth, tumorigenicity in nude mice and elevation of active Ras-GTP levels. These results indicated that this novel mutation possesses high oncogenic activity.