Human amniotic membrane-derived mesenchymal stem cells (hAM-MSCs) are capable of differentiating into several lineages and possess immunomodulatory properties. In this study, we investigated the soluble factor-mediated immunomodulatory effects of hAM-MSCs. Mitogen-induced peripheral blood mononuclear cell (PBMC) proliferation was suppressed by hAM-MSCs in a dose-dependent manner as well as hAM-MSC culture supernatant. Moreover, interferon-gamma and interleukin (IL)-17 production significantly decreased from PBMC, whereas IL-10 from PBMCs and transforming growth factor beta (TGF-β) production from hAM-MSCs significantly increased in co-cultures of hAM-MSCs and PBMCs. Production of several MSC factors, including hepatocyte growth factor (HGF), TGF-β, prostaglandin E2 (PGE2), and indoleamine 2, 3 dioxygenase (IDO), increased significantly in hAM-MSCs co-cultured with PBMCs. These results indicate that the immunomodulatory effects of hAM-MSCs may be associated with soluble factors (TGF-β, HGF, PGE2, and IDO), suggesting that hAM-MSCs may have potential clinical use in regenerative medicine.

To identify candidate genes that could be used as diagnostic and therapeutic targets for hepatocellular carcinoma (HCC), we searched for the genes that are overexpressed in HCC by combining representational difference analysis and microarray. Genes such as glypican-3 (GPC3), insulin-like growth factor 2, long-chain fatty-acid-coenzyme A ligase 4, farnesyl diphosphate synthase were frequently identified in our screening. Northern blot analysis with these four genes confirmed their overexpression in HCC. Among them we found that GPC3 transcript is upregulated in six out of seven cases of HCC. Immunoblot and immunohistochemical staining using polyclonal anti-GPC3 antibodies further confirmed that GPC3 protein is indeed increased in HCC tumor samples. We also found that GPC3 is secreted into culture media from cell lines derived from HCC. We conclude that GPC3 is a good molecular marker for HCC. (Cancer Sci 2003; 94: 259-262) lypican-3 (GPC3) is a member of the glypican family of heparan-sulfate proteoglycans, which are linked to the cell surface through a glycosylphosphatidylinositol anchor.1) GPC3 loss-of-function mutation in human causes type 1 Simpson-Golabi-Behmel syndrome (SGBS1), an X-linked condition characterized by pre-and postnatal overgrowth.2) GPC3 knockout mice indeed exhibited several phenotypic features of SGBS1. [3][4][5] These findings together with cell line-specific promotion of apoptosis by OCI-5/GPC3 6) suggest that GPC3 plays a negative role in cell proliferation and an apoptosis-inducing role in specific tissues.Consistent with the above idea, GPC3 expression is frequently silenced by promoter methylation in ovarian cancer cell lines, 7) rat mesothelioma cell lines and human primary tumors, 8) and breast cancer cell lines. 9) In addition, ectopic expression of GPC3 inhibited growth in some of the above cell lines, suggesting a tumor-suppressive role of GPC3. In contrast, GPC3 is known to be overexpressed in hepatocellular carcinoma, 10,11) neuroblastoma and Wilms' tumor cells.12) The role of GPC3 in these tumors is not known. It is also not known whether GPC3 protein is indeed increased in these tumors.Hepatocellular carcinoma (HCC) is one of the most common tumors worldwide and is one of the leading causes of death among cancer patients in Korea. Identification of genes that are overexpressed in HCC not only helps our understanding of tumorigenesis, but also helps to develop diagnostic and therapeutic targets. In this study, we combined representational difference analysis (RDA) 13) and microarray 14) to identify genes that are frequently overexpressed in HCC tumor samples. Since GPC3 was the most frequently obtained gene in our screening, we further evaluated it as a tumor marker for HCC. Materials and MethodsTumor samples and cell lines. HCC tumor tissues and corresponding normal liver tissues were obtained from patients (Table 1) undergoing surgery in Kyungpook National University Hospital (Daegu, Korea) with the approval of the human research review committee and the patients' consent. C...

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Cocolonization of human mucosal surfaces causes frequent encounters between various staphylococcal species, creating opportunities for the horizontal acquisition of mobile genetic elements. The majority of Staphylococcus aureus toxins and virulence factors are encoded on S. aureus pathogenicity islands (SaPIs). Horizontal movement of SaPIs between S. aureus strains plays a role in the evolution of virulent clinical isolates. Although there have been reports of the production of toxic shock syndrome toxin 1 (TSST-1), enterotoxin, and other superantigens by coagulase-negative staphylococci, no associated pathogenicity islands have been found in the genome of Staphylococcus epidermidis, a generally less virulent relative of S. aureus. We show here the first evidence of a composite S. epidermidis pathogenicity island (SePI), the product of multiple insertions in the genome of a clinical isolate. The taxonomic placement of S. epidermidis strain FRI909 was confirmed by a number of biochemical tests and multilocus sequence typing. The genome sequence of this strain was analyzed for other unique gene clusters and their locations. This pathogenicity island encodes and expresses staphylococcal enterotoxin C3 (SEC3) and staphylococcal enterotoxin-like toxin L (SElL), as confirmed by quantitative reverse transcription-PCR (qRT-PCR) and immunoblotting. We present here an initial characterization of this novel pathogenicity island, and we establish that it is stable, expresses enterotoxins, and is not obviously transmissible by phage transduction. We also describe the genome sequence, excision, replication, and packaging of a novel bacteriophage in S. epidermidis FRI909, as well as attempts to mobilize the SePI element by this phage.

nesterified arachidonic acid (also called free AA) entering cells exogenously or released endogenously is rapidly converted to AA-CoA esters by the catalytic action of fatty acidCoA ligase (FACL), particularly by the AA-preferring FACL4.1, 2) Several lines of evidence indicated that the level of free AA in cells regulates apoptosis.3-7) More recently, it has been demonstrated that free AA induces apoptosis by activating the caspase-3 pathway, and that the induction of apoptosis by inhibitors of AA metabolism is a consequence of its accumulation.8) Moreover, overexpression of FACL4 prevented AA-induced apoptosis by reducing the level of intracellular free AA. 8)These findings, together with overexpression of FACL4 in colon adenocarcinoma, strongly suggest that the FACL4 pathway may be important in colon carcinogenesis.9) In addition, cyclooxygenase-2 (Cox-2), another AA-utilizing enzyme, is also known to be overexpressed in colon cancer.10, 11) Therefore, AA metabolism plays an important role in colon carcinogenesis. Currently, overexpression of FACL4 and Cox-2 in colon adenocarcinoma is believed to deplete free AA, thereby removing a proapoptotic signal and promoting carcinogenesis. 8,9) Hepatocellular carcinoma (HCC) is one of the most common tumors worldwide and is one of the leading causes of death among cancer patients in Korea. Identification of genes that are overexpressed in HCC is of importance to understand liver tumorigenesis and to develop diagnostic and therapeutic targets. As is seen in colon cancer, Cox-2 is known to be overexpressed in human HCC, [12][13][14] implying that AA metabolism might also be important in liver carcinogenesis. However, it is not known whether FACL4 is also overexpressed in HCC. It is known that human placenta, brain, testis, ovary, spleen, and adrenal cortex express high levels of FACL4, whereas the gastrointestinal system, including liver, expresses a very low level.2) In a recent paper, 15) we reported that FACL4 is frequently upregulated in HCC compared to chronic hepatitis, as revealed by highthroughput screening combining RDA and microarray. We think that assessing the status of FACL4 in HCC is of importance to check whether the FACL4 pathway is also involved in liver carcinogenesis. Therefore, in this study, we investigated FACL4 upregulation in tumor cells of HCC and in cell lines derived from hepatoma. Materials and MethodsTumor samples and cell lines.

Staphylococcus aureus is a major pathogen of humans and animals. The capacity of S. aureus to adapt to different host species and tissue types is strongly influenced by the acquisition of mobile genetic elements encoding determinants involved in niche adaptation. The genomic islands νSaα and νSaβ are found in almost all S. aureus strains and are characterized by extensive variation in virulence gene content. However the basis for the diversity and the mechanism underlying mobilization of the genomic islands between strains are unexplained. Here, we demonstrated that the genomic island, νSaβ, encoding an array of virulence factors including staphylococcal superantigens, proteases, and leukotoxins, in addition to bacteriocins, was transferrable in vitro to human and animal strains of multiple S. aureus clones via a resident prophage. The transfer of the νSaβ appears to have been accomplished by multiple conversions of transducing phage particles carrying overlapping segments of the νSaβ. Our findings solve a long-standing mystery regarding the diversification and spread of the genomic island νSaβ, highlighting the central role of bacteriophages in the pathogenic evolution of S. aureus.

Bovine mastitis can be diagnosed by abnormalities in milk components and somatic cell count (SCC), as well as by clinical signs. We examined raw milk in Korea by analyzing SCC, milk urea nitrogen (MUN), and the percentages of milk components (milk fat, protein, and lactose). The associations between SCC or MUN and other milk components were investigated, as well as the relationships between the bacterial species isolated from milk. Somatic cell counts, MUN, and the percentages of milk fat, protein, and lactose were analyzed in 30,019 raw milk samples collected from 2003 to 2006. The regression coefficients of natural logarithmic-transformed SCC (SCCt) on milk fat (-0.0149), lactose (-0.8910), and MUN (-0.0096), and those of MUN on milk fat (-0.3125), protein (-0.8012), and SCCt (-0.0671) were negative, whereas the regression coefficient of SCCt on protein was positive (0.3023). When the data were categorized by the presence or absence of bacterial infection in raw milk, SCCt was negatively associated with milk fat (-0.0172), protein (-0.2693), and lactose (-0.4108). The SCCt values were significantly affected by bacterial species. In particular, 104 milk samples infected with Staphylococcus aureus had the highest SCCt (1.67) compared with milk containing other mastitis-causing bacteria: coagulase-negative staphylococci (n = 755, 1.50), coagulase-positive staphylococci (except Staphylococcus aureus; n = 77, 1.59), Streptococcus spp. (Streptococcus dysgalactiae, n = 37; Streptococcus uberis, n = 12, 0.83), Enterococcus spp. (n = 46, 1.04), Escherichia coli (n = 705, 1.56), Pseudomonas spp. (n = 456, 1.59), and yeast (n = 189, 1.52). These results show that high SCC and MUN negatively affect milk components and that a statistical approach associating SCC, MUN, and milk components by bacterial infection can explain the patterns among them. Bacterial species present in raw milk are an important influence on SCC in Korea.

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