Expression of Heme Oxygenase-1 in Ischemic Colitis / 대한소화기학회지

BACKGROUND/AIMS: Ischemic colitis is a vascular condition of inadequate blood flow in the colon which leads to colonic inflammation and can cause significant morbidity and mortality. Oxidative stress is an early initiating event in ischemia and reperfusion injury. Heme oxygenase (HO) is considered to be an antioxidant enzyme that catabolizes heme to carbon monoxide, free iron and biliverdin. The aim of this study was to evaluate the expression patterns of HO-1, inducible form of HO, in ischemic colitis. METHODS: We analyzed the twelve cases of clinically and pathologically diagnosed ischemic colitis without surgical intervention compared with normal colon (n=10) and psedomembranous colitis (n=5). Immunohistochemical stainings for HO-1 were performed in paraffin-embedded tissues. RESULTS: The age of the patients ranged from 56 to 84 years (mean: 67 years) in ischemic colitis. Eight patients (66.7%) were female. The most common presenting symptom was bloody stool (66.7%) and rectosigmoid area (91.7%) of the large intestine was the most common ischemic site. Expression of HO-1 in ischemic colitis was high in contrast to normal colonic mucosa or psedomembranous colitis. CONCLUSIONS: Ischemic colitis usually involves the rectosigmoid area in elderly female patients with a history of bloody stool. High expression of HO-1 in ischemic colitis may be responsible for a protective mechanism to ischemia or heme injury.

Roles of FGF-4 on the Differentiation of Trophoblast Stem (TS) Cells / 대한해부학회지

Fibroblast growth factor-4 (FGF-4) has various functions, affecting many signaling pathways, and leading to cellular proliferation and differentiation and to the regulation of cell migration, invasion, and angiogenesis. However, there are few reports of the relationship between TS cells and FGF-4 even if FGF-4 is located in inner cell mass of embryo and Fibroblast growth factor receptor (FGFR) is located in TS cells. Therefore the physiologic effects of FGF-4 on TS cells were investigated for identifying the effects of FGF-4 on TS ell differentiation. FGF-4 was involved in early stage development of the trophoblast via upregulation of eomesodermin mRNA expression. In addition, FGF-4 suppressed the differentiation of TS cells through activation of extracellular-signal regulated kinase (Erk) and suppression of focal adhesion kinase (FAK) activation, which in TS cells is an important indicator of early trophoblast cell differentiation, migration and invasion. FGF-4 was involved in angiogenesis in the trophoblast through the activation of p38 and the induction of Dlx-3 mRNA expression in TS cells. In addition, TS cells cultured with FGF-4 for 4 days in a thrombinfibrinogen gel culture system, a specific culture system for endothelial cells, showed a healthy appearance, while TS cells cultured without FGF-4 were severely damaged. Taken together, these data suggest that FGF-4 is closely involved in differentiation of TS cells for development of placenta.

Rebamipide Protects Colonic Damage Induced by Trinitrobenzene Sulfonic Acid (TNBS) via Down-Regulation of TNF-alpha IL-1beta and ICAM-1 / 대한해부학회지

During inflammation of the colon, cells of the gut mucosa produce or express numerous inflammatory mediators, such as tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1 beta), and intercellular adhesion molecule 1 (ICAM-1). These mediators have been implicated as contributory factors to the inflammatory process, which results in colitis during inflammatory bowel disease (IBD). Rebamipide is an anti-gastric ulcer drug with anti-inflammatory properties in vivo and in vitro. The effects of Rebamipide on IBD have not been largely evaluated. Therefore, this study investigated the potential of Rebamipide to regulate the production of inflammatory mediators such as TNF-alpha, IL-1beta, and ICAM-1. Mice with trinitrobenzene sulfonic acid (TNBS)-induced colitis (IBD animal model), were treated intrarectally with 2 mM Rebamipide. Body weight, macro- and micro-histological scores, and activity were evaluated. As an index of tissue edema, the thickness of the colonic wall was measured between the serosal surface and the luminal surface of the mucosa. TNF-alpha, IL-1 beta, and ICAM-1 were detected by immunohistochemical staining. Rebamipide treatment of mice exhibiting TNBS-induced colitis dramatically improved the clinical and histopathological findings of inflammation. In addition, Rebamipide suppressed TNF-alpha, IL-1 beta, and ICAM-1 expression in TNBS-treated animals. Taken together, these findings suggest that Rebamipide is a potential therapeutic agent for treating patients with IBD.

Protective Effect of PKC and Nitric Oxide Affecting Taxol-Induced Cytotoxicity in C6-Gial Cells / 대한해부학회지

Paclitaxel (Taxol) is known as effective drug for inhibition of cell cycle encouraging in human cancer cells. This drug named an antimicrotubule agent which simulate the mitotic arrest towards an apoptosis. The influence of phorbol 12 myristate 13 acetate (PMA) activated protein kinase C (PKC) and nitric oxide (NO) on taxol-induced apoptosis, is poorly understood. To investigate the effects of PMA and NO on the signal transduction in taxol-induced apoptosis in C6-glial cells, the viability and caspase-3 activity of C6-glial cells were analyzed. Pretreatement with PKC activatior (PMA) protected taxol-induced cell death in C6-glial cells, by inhibited caspases-3 activity. On the other hand, the taxol-induced apoptosis was highly enhanced by sodium nitroprusside (SNP) and lipopolysaccharide (LPS), as NO activator. These results suggest that PMA strongly blocks the apoptotic effect of taxol, while nitric oxide has no protective effects in the process of toxol-induced apoptosis in C6-glial cells.

Protective Effect of PKC Affecting Gliotoxin-induced Cytotoxicity in Rat Smooth Muscle Cells / 대한해부학회지

Aspergillus funigatus and other pathogenic fungi synthesize a toxic epidithi-odiopiperzine (ETP) metabolite, namely gliotoxin. Gliotoxin commonly react with sulfhydryl groups, and then, forms hydrogen peroxide. These fungal toxins induce apoptotic cell death in various cells. Apoptosis induced by gliotoxin need calcium. Effect of calcium preconditioning was not reported in gliotoxin-induced apoptosis. To examine the effect of protein kinase C (PKC) and calcium which was regulate caspase-3, PKC and calcium preconditioning before gliotoxin treatment, apoptotic agents such as bcl-2 family, caspase-3 and DNA fragmentation in A7r5 cell line from rat smooth muscle cell were studied. These results showed that gliotoxin induces the expression of bad of bcl-2 family, caspase-3 activation and DNA fragmentation in A7r5 cells. Gliotoxin treatment followed by calcium and PKC preconditioning suppress the Bad of bcl-2 family, and inhibited caspase-3 activation, respectively. These results suggest that PKC and calcium preconditioning protect the gliotoxin-induced apoptosis, through the protection of pro-apoptotic bcl-2 family in A7r5 cells.

The Effect of Protein Kinase C Pretreatment on Gliotoxin Induced Apoptosis in H9c2 Cells / 체질인류학회지

Aspergillus funigatus and other pathogenic fungi synthesize a toxic epidithi- odiopiperzine (ETP) metabolite called gliotoxin. Gliotoxin is an epidithiodiopiperzine compound which can both react with sulfhydryl groups and form hydrogen peroxide. The fungal toxin gliotoxin induces apoptotic cell death in a variety of cells. Apoptosis induced by gliotoxin need calcium but effect of calcium preconditioning is unknown by gliotoxin. We studied the effect of protein kinase C and calcium preconditioning on gliotoxin-induced apoptosis in H9c2 cell. PKC and calcium preconditiong inhibited DNA fragmentation by gliotoxin. From this above results suggest that gliotoxin induce apoptosis via caspase-3 activation, because caspase-3 inhibitor (DEVD-CHO) didn't induce apoptosis in gliotoxin treated H9c2 clls. Calcium and PKC preconditioning inhibit caspase-3 activation by gliotoxin. These data means that PKC preconditioning is related with caspase-3 regulate in gliotoxin-induced apoptosis.

Protective Effect of PKC Affecting Taxol-induced Cytotoxicity in MCF-7 Cells / 대한해부학회지

Paclitaxel (taxol) is known as effective drug inhibition of cell cycle encouraging activity in human ovarian and metastatic breast cancers and malignant melanoma. It is an antimicrotubule agent that is believed to mediate its antineoplastic effects by inducing mitotic arrest followed by apoptosis. The relation between phorbol 12 myristate 13 acetate (PMA), protein kinase C (PKC) activator, and taxol-induced apoptosis is not well understood until now. This study was performed to investigate the effects of PMA on the signal transduction pathways of taxol-induced apoptosis in MCF-7 human breast carcinoma cells. Taxol-induced apoptosis is attenuated by curcumine, JNK inhibitor, and pyrrolidine dithiocarbamate (PDTC), inhibitor of NFkB. Pretreatment with PKC activator (PMA) or protein kinase A (PKA) activators (forskolin and dibutyryl cAMP) inhibited taxol-induced apoptosis in MCF-7 cells. In addition, thapsigargin, a specific inhibitor of endoplasmic reticulum(ER) Ca(2+)-ATPase and CaCl2, also blocked the activation of caspases by taxol. From these results suggest that taxol-induced apoptosis may be mediated via JNK or NFkB pathway and PKC activation.

Protective Effect of Nitric Oxide Against Lipopolysaccharide-induced Cytotoxicity in C6-glial Cell / 대한해부학회지

Nitric oxide (NO) is mainly involved in brain ischemic damage to elucidate the protective mechanism of NO pretreatment on ischemic-induced cytotoxicity. This study was investigated whether NO pretreatment inhibits the increase of iNOS expression by lipopolysaccharide (LPS) combined phorbol 12-myristate 13-acetate (PMA) via regulating NF-kB activation in C6 glial cells. C6 glial cells with LPS and PMA for 72 hours markedly induced NO, but sodium nitroprusside (SNP) (100 nM) pretreatment before exposure of LPS and PMA significantly supressed NO production, iNOS expression and NF-kB activation by LPS and PMA. In addition, LPS and PMA treatment for 72 hours induced severely cell death and LDH release from cell into media in C6 glial cells. However SNP pretreatment before treatment of LPS and PMA significantly protected LPS and PMA induced cytotoxicity. Treatment with LPS and PMA induced caspase 3 activation follewed by chromosomal condensation, and fragmentation of nuclei in C6 glial cells. SNP pretreatment before exposure to LPS and PMA supressed caspase 3 activation and inhibited chromosomal condensation and fragmentation of nuclei. From these above results, it is suggest that the protective effects of SNP pretreatment against LPS and PMA induced cytotoxicity may be mediated by inhibiting the expression of iNOS via regulating NF-kB activation.

The Role of Calcium Affecting Signal Pathway Related to Nitric Oxide-induced Cytotoxicity in H9c2 Cardiac Myoblast / 대한해부학회지

Nitric oxide (NO) elevates intracellular calcium. But the actions of calcium in NO-induced cell death are not well understood. This study was carried out to investigate the signal transduction pathways of calcium and NO-induced cytotoxicity in H9c2 cardiac myoblasts by using NO donor compounds such as sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine (SNAP). Pretreatment of intracellular calcium chelating agent (BAPTA/AM) or L-type calcium channel blockers (nicardipine, nifedipine, diltiazem and veraparmil) or T-type calcium channel blocker (flunarizine) blocked SNP-induced cytotoxicity respectively only in a three hours. However, thapsigargin (TG), which inhibits endoplasmic reticulum dependent Ca(2+)-ATPase and thereby increases cytosolic Ca(2+), augmented SNP-induced cytotoxicity. The protective effect of BAPTA/AM was inhibited by treatment of protein synthesis inhibitor, cyclohexamide. In addition, pyrrolidine dithiocarbamate (PDTC), NF-kB inhibitor, attenuates the protective effect of BAPTA/AM against SNP-induced cytotoxicity. It is indicated that the protective effect of BAPTA/AM against NO-induced cytotoxicity might be due to the expression of protein related to activation of NFkB. From these results, it is concluded that SNP-induced cytotoxicity is mediated by calcium in a 3 hours via down regulation of protein expression rleated to activation of NFkB.