Toshiharu Sakurai

Dose-Dependent Differential Regulation of Cytokine Secretion from Macrophages by Fractalkine

Although expression of the fractalkine (CX3CL1, FKN) is enhanced in inflamed tissues, it is detected at steady state in various organs such as the intestine, and its receptor CX3CR1 is highly expressed in resident-type dendritic cells and macrophages. We hypothesized that FKN might regulate the inflammatory responses of these cells. Therefore, murine macrophages were pretreated with FKN and then stimulated with LPS. We found that macrophages pretreated with 0.03 nM FKN but not with 3 nM FKN secreted 50% less TNF-α than did cells treated with LPS alone. Cells treated with 0.03 nM FKN and LPS also showed reduced phosphorylation of ERK1/2 and reduced NF-κB p50 subunit. Interestingly, the p65 subunit of NF-κB was translocated to the nuclei but redistributed to the cytoplasm in the early phase by forming a complex with peroxisome proliferator-activated receptor (PPAR) γ. Exogenous 15-deoxy-Δ(12,14)-prostaglandin J2, a natural ligand for PPAR-γ, also induced redistribution of p65 with decreased TNF-α secretion after LPS challenge. Pretreatment with 0.03 nM but not 3 nM FKN increased the cellular levels of 15-deoxy-Δ(12,14)-prostaglandin J2 as well as mRNA of PPAR-γ. Requirement of PPAR-γ for the effect of 0.03 nM FKN was confirmed by small interfering RNA of PPAR-γ. In contrast, pretreatment with 3 nM FKN induced higher levels of IL-23 compared with cells pretreated with 0.03 nM FKN and produced TNF-α in a CX3CR1-dependent manner. These dose-dependent differential effects of FKN establish its novel role in immune homeostasis and inflammation.

Liver abscess caused by Clostridium difficile.

We report the first case of an infected cyst and liver abscess caused by Clostridium difficile. It recurred 11 months later, despite therapy with vancomycin and percutaneous drainage. Administration of metronidazole following percutaneous drainage achieved a favorable outcome.We report the first case of an infected cyst and liver abscess caused by Clostridium difficile. It recurred 11 months later, despite therapy with vancomycin and percutaneous drainage. Administration of metronidazole following percutaneous drainage achieved a favorable outcome.

Apg-2 has a chaperone-like activity similar to Hsp110 and is overexpressed in hepatocellular carcinomas

Hepatocellular carcinoma (HCC) is the fifth most common cancer in the world. We constructed subtracted cDNA libraries enriched with genes overexpressed in HCCs. Among the 17 genes identified were molecular chaperones, Hsp110, Hsp90B, and Hsp70‐1. Expression of the Hsp110 family members was further analyzed, and increased transcript levels of Hsp110 and Apg‐2, but not Apg‐1, were found in 12 and 14, respectively, of 18 HCCs. Immunohistochemical analysis demonstrated the overexpression of the proteins in tumor cells. Apg‐2 had chaperone ability similar to Hsp110 in a thermal denaturation assay using luciferase, and showed anti‐apoptotic activity. These results suggest that the Hsp110 family members play important roles in hepatocarcinogenesis through their chaperoning activities.

Restoration of RUNX3 enhances transforming growth factor-β-dependent p21 expression in a biliary tract cancer cell line

RUNX3 is a candidate tumor suppressor gene localized in 1p36, a region commonly inactivated by deletion and methylation in various human tumors. To elucidate the role of RUNX3 in transforming growth factor (TGF)‐β signaling in biliary tract cancer, we transfected Mz‐ChA‐2 cells, which do not express RUNX3 but have intact TGF‐β type II receptor and SMAD4 genes, with the RUNX3 expression plasmid pcDNA3.1/RUNX3 or with the vector pcDNA3.1 as a control. Four Mz‐ChA‐2/RUNX3 clones and one control clone were obtained. Although TGF‐β1 only slightly inhibited growth of the control cells, growth inhibition and TGF‐β‐dependent G1 arrest were significantly enhanced in the RUNX3‐transfected clones. None of the clones, however, exhibited apoptosis. The slightly increased TGF‐β1‐induced p21 expression in the control clone was strongly enhanced in the RUNX3‐transfected clones, and was accompanied by augmented decreases in the expression of cyclins D1 and E. When RUNX3 small interfering RNA was added, TGF‐β‐dependent induction of p21 was reduced in the RUNX3‐transfected clones. Xenografts of the clones in nude mice demonstrated that tumorigenicity was significantly decreased in the RUNX3‐transfected clones in inverse proportion to the expression levels of RUNX3. Based on these results, RUNX3 is involved in TGF‐β‐induced expression of p21 and the resulting induction of TGF‐β‐dependent G1 arrest. (Cancer Sci 2007; 98: 838–843)

Lens culinaris agglutinin-A-reactive alpha-fetoprotein as a marker for liver atrophy in fulminant hepatic failure.

Liver atrophy is frequently found at autopsy of patients with fulminant hepatic failure (FHF). Imaging studies in patients with FHF demonstrate that estimation of total liver volume correlates with prognosis. In this study, in order to determine serum markers for evaluating liver atrophy, we measured the weight of whole livers resected from 31 transplant recipients with FHF, and assessed the relation between the liver weights and several prognostic markers. The level of liver atrophy was evaluated by calculating the ratio of the removed whole liver weight to the body weight of each recipient, and 16 major variables including several serological markers were analyzed among those recipients. We found that the serum Lens culinaris agglutinin-A-reactive alpha-fetoprotein (AFP-L3) levels were significantly higher in patients with FHF than in those with other liver diseases. In FHF patients, the serum AFP-L3 level at the onset of encephalopathy was significantly higher in cases with mild atrophy than in those with severe atrophy (P<0.05). Notably, the residual liver volume was significantly correlated with the serum AFP-L3 level (Pearsons correlation coefficient=0.63), but not with AFP. In conclusion, AFP-L3 is a possible serum marker for evaluating liver atrophy and/or liver regeneration in patients with FHF.