Ae-Ri Ji

Vitamin C deficiency attenuates liver fibrosis by way of up-regulated peroxisome proliferator-activated receptor-gamma expression in senescence marker protein 30 knockout mice.

Senescence marker protein 30 (SMP30), an important aging marker molecule that is highly expressed in the liver, has been known to protect hepatocytes from apoptosis by the synthesis of vitamin C. To explore the function of SMP30 in liver fibrosis, the effect of SMP30 deficiency on liver fibrosis was investigated in SMP30 knockout (KO) mice. Moreover, the in vivo results were further confirmed by way of hepatic stellate cell (HSC) isolation. We demonstrated that carbon tetrachloride (CCl4)‐induced liver fibrosis and the nuclear translocation of p‐Smad2/3, the immediate downstream of transforming growth factor beta (TGF‐β), were significantly inhibited in the liver of SMP30 KO mice compared with wildtype (WT) mice. We also confirmed that both WT and SMP30 KO HSCs did not express SMP30. Finally, we further confirmed that up‐regulation of peroxisome proliferator‐activated receptor‐gamma (PPAR‐γ) caused by a lack of vitamin C was the pivotal factor in the mechanisms for attenuated liver fibrosis of SMP30 KO mice, and feeding with vitamin C restored CCl4‐induced liver fibrosis in SMP30 KO mice. Conclusion: Vitamin C deficiency by SMP30 depletion attenuated liver fibrosis by way of up‐regulated PPAR‐γ expression in SMP30 KO mice. Our results provide, for the first time, the possible mechanisms underlying inhibition of HSC activation associated with vitamin C and PPAR‐γ up‐regulation in liver fibrosis of SMP30 KO mice. (HEPATOLOGY 2010.)

Helicobacter pylori accelerates hepatic fibrosis by sensitizing transforming growth factor-β1-induced inflammatory signaling

Our earlier report has shown that Helicobacter pylori promoted hepatic fibrosis in a murine model. Herein, in order to elucidate the mechanism by which H. pylori accelerate liver fibrosis, the authors investigated the changes in expression levels of mitogen-activated protein kinases (MAPKs), p53-related proteins, antioxidants, and proinflammatory cytokines in liver samples. H. pylori infection enhanced CCl4-induced MAP kinase activation and p53 signaling pathway as well as Bax- and proliferating-cell nuclear antigen expressions, whereas H. pylori alone induced neither of these expressions nor hepatic fibrosis. Moreover, mRNA expressions of inflammatory cytokines, glutathione peroxidase expression, and the proliferative index were strongly augmented in livers of the H. pylori with CCl4 treatment group compared with those of the CCl4-alone treatment group, whereas there was no difference in apoptotic index between the two groups. Interestingly, H. pylori treatment increased the number of α-fetoprotein-expressing hepatocytes independently of CCl4 intoxication. In vitro analyses, using an immortalized rat hepatic stellate cell (HSC) line, revealed that H. pylori lysates increased the proliferation of HSCs, which was boosted by the addition of transforming growth factor-beta1 (TGF-β1). Furthermore, the treatment of H. pylori lysates promoted the translocation of nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB) into the nucleus based on an increase in the degradation of NF-κB inhibitor alpha, in the presence of TGF-β1, as did H2O2 treatment. In conclusion, H. pylori infection along with an elevated TGF-β1 may accelerate hepatic fibrosis through increased TGF-β1-induced pro-inflammatory signaling pathways in HSCs. Moreover, H. pylori infection might increase the risk of TGF-β1-mediated tumorigenesis by disturbing the balance between apoptosis and proliferation of hepatocytes.

In Vitro Inhibition of Helicobacter pylori Growth and of Adherence of cagA-Positive Strains to Gastric Epithelial Cells by Lactobacillus paraplantarum KNUC25 Isolated from Kimchi

Lactobacillus paraplantarum KNUC25 strain was isolated from overfermented kimchi, a Korean traditional food. The strain had a broad antimicrobial activity spectrum, from gram-positive to gram-negative bacteria. The aim of this study was to evaluate the activity of L. paraplantarum KNUC25 against Helicobacter pylori strains. Judged by a disc agar diffusion method, the anti-H. pylori activity existed in the cell-free supernatants (CFSs) of KNUC25. The mean diameters of growth inhibition by 10, 30, and 60 microL of a 15-fold concentrated CFS per disc were 11.2, 17.7, and 23.7 mm, respectively. The neutralized CFS lost its anti-H. pylori activity, suggesting that acidic pH in CFS may be responsible for the anti-H. pylori activity. Adherence was determined by urease activity of H. pylori adhered to gastric epithelial cell line AGS cells after co-incubation of AGS cells with CFS and H. pylori strain ATCC43504 (s1m1vacA/cagA(+)), ATCC51932 (s2m2vacA/cagA(-)), or SS1 (s2m2vacA/cagA(+)) in vitro followed by three washes by means of centrifugation with saline. Adherence of ATCC43504 or SS1 to AGS cells was reduced by about 70% after a 30-minute incubation with 30 microL of a 15-fold concentrated KNUC25 CFS, whereas that of ATCC51932 to AGS cells was not. The results show KNUC25 CFS is effective in inhibiting the growth of H. pylori, which is related to pH and the adherence of cagA-positive H. pylori to gastric cells.

Vitamin C deficiency increases the binucleation of hepatocytes in SMP30 knock‐out mice

Background and Aims:  The binucleation of hepatocytes, which was known as an important feature of liver growth and physiology, has been reported to be increased during the chronic oxidative injury stage and has been regarded as an age‐related change of hepatic structures. Therefore, we investigated the binuclearity pattern in the livers of senescence marker proteins‐30 (SMP30) knock‐out (KO) mice compared with wild‐type (WT) mice and vitamin C‐treated KO (KO + VC) mice.

Molecular basis for age-related changes in ileum: Involvement of Bax/caspase-dependent mitochondrial apoptotic signaling

Previous studies indicate that in the elderly, a morphological change in the small intestine is accompanied by apoptosis. However, currently little information is available on the molecular events leading up to the apoptotic process in aged ileum. Our current study assessed mitochondrial apoptotic signaling along with key factors known to be involved in mitochondrial permeabilization in rat ileum. Experimentations were carried out utilizing Sprague-Dawley rats at 6 and 24 months of age. The histological analysis showed a significant loss in thickness of the intestinal mucosa during aging, which was accompanied by higher reactive species. Molecular analysis revealed the mitochondrial translocation of Bax showed a significant increase with aging. However, the expression of cyclophilin D, adenine nucleotide translocator, and the voltage-dependent anion channel that regulates the mitochondria permeability transition pore decreased or remained unchanged. Furthermore, the expression of caspase 3 was enhanced in aged ileum with increased DNA fragmentation, while nuclear translocation of apoptosis-inducing factor and endonuclease G were decreased with aging. In conclusion, our findings indicate that the mitochondrial translocation of Bax by increased oxidative stress may result in cell death through caspase-dependent apoptosis in aged ileum, thereby leading to a decrease in intestinal mucosal thickness during aging.

Antimicrobial effects of coprisin on wounds infected with Staphylococcus aureus in rats.

Antimicrobial peptides (AMPs) are naturally produced antibiotics that play important roles in host defense mechanisms. These proteins are found in variety of animal and plant species. The antibiotic effects of AMPs are gaining attention for use in human medicine. In this study, the antimicrobial effects of coprisin, a novel AMP isolated from the dung beetle (Copris tripartitus), were evaluated. The peptide was used to treat rats with wounds infected with Staphylococcus aureus. Coprisin accelerated wound closure both grossly and microscopically compared with the untreated group. Additionally, treatment with this peptide decreased phosphorylated‐Smad2/3 (p‐Smad2/3) levels, a downstream factor of the transforming growth factor‐β signaling pathway which is believed to inhibit reepithelization, in the nucleus and cytoplasm of regenerating cells. Moreover, increased cell populations and angiogenesis were observed in lesions treated with coprisin, suggesting that this peptide promotes wound healing via its antimicrobial activity against S. aureus. Our results demonstrated that coprisin is a potential therapeutic agent that can possibly replace traditional antibiotics and overcome microbial resistance.

Subcutaneous leiomyosarcoma in an adrenomedullin heterozygous mouse

The present study reports a case of a 5-month-old female adrenomedullin (AM) heterozygous (+/-) mouse that presented a mass of leiomyosarcoma found in the right shoulder girdle region. The neoplastic mass extended to the sternal region and showed hemorrhages, congestion and necrotic foci. The excised tumor with a diameter of 2.5cm was firm, ill-demarcated and had focally infiltrated the surrounding muscles. The cut surface was homogeneously whitish with multi-focal reddish lesions. Microscopically, the tumor composed of variable fascicles of spindle-shaped cells with pleomorphic and cigar-shaped nuclei. The nuclei were round and elongated. Metastasis of tumor cell to skeletal muscle was frequently observed. Immunohistochemically, desmin, vimentin and alpha-smooth muscle actin (alpha-SMA) were demonstrated in neoplastic cells but tumor cells were negative for cytokeratin (CK) and S-100. Based on gross finding, microscopical examination and immunohistochemistry, the present case was diagnosed as a subcutaneous leiomyosarcoma.

Two different types of malignant fibrous histiocytomas from pet dogs

We describe 2 cases of malignant fibrous histiocytomas (MFHs) that spontaneously developed in young pet dogs. To classify these tumors, we applied a panel of antibodies (vimentin, desmin, α-SMA, and ED1) and Azan staining for collagen. The MFHs were most consistent with osteoclast-like giant and inflammatory cell types. The first case had positive staining for ED1 and vimentin, and given the osteoclast-like giant cells, calcification sites accompanying peripheral giant cell infiltrates. The latter case, the inflammatory cell type, exhibited a storiform-pleomorphic variant of neoplastic cells, including an ossifying matrix. MFHs are among the most highly aggressive tumors occurring in soft tissue sarcomas in elderly dogs; however, MFHs have been poorly studied from a diagnostic point of view. Herein, we describe the histologic and immunohistologic features of MFHs in detail, thus classifying the subtypes of these tumors.

Adrenomedullin Deficiency Increases the Susceptibility of Liver Fibrosis Induced by CCl 4

Adrenomedullin (AM) is a peptide expressed in all body tissues, and its related receptors are increased in liver fibrosis. In this study, we evaluated the effect of AM deficiency on liver fibrogenesis induced by CCl 4 using AM heterozygous (HT) mice. The animals received a single injection of CCl 4 or olive oil for the acute experiment, and received CCl 4 or olive oil three times a week for 6 weeks for the chronic experiment. Fibrosis was accessed using histopathological analysis and the western blot. The AM HT mice showed mild pericentrilobular degeneration when compared to the AM wild type (WT) mice. In the acute experiment, there was no significant difference between the AM WT and AM HT mice. However, in the chronic experiment, the CCl 4 -treated AM HT mice showed more severe liver fibrosis than that of the CCl 4 -treated AM WT mice. The AST and ALT levels of the AM HT CCl 4 group were higher than those of the AM WT CCl 4 group. Additionally, the collagen deposition, α-SMA protein and TGF-β protein were increased in the AM HT CCl 4 group when compared to the AM WT CCl 4 group. The AM HT mice also exhibited severe lipid peroxidation through the GSH decrement. Taken together, our data suggest that AM deficiency increases the susceptibility to liver fibrosis induced by CCl 4 , indicating a novel therapeutic target for patients with liver fibrosis.