VDUP1 Deficiency Promotes the Severity of DSS-Induced Colitis in Mice by Inducing Macrophage Infiltration.

The loss of vitamin D3 upregulated protein 1 (VDUP1) has been implicated in the pathogenesis of various inflammation-related diseases. Notably, reduced expression of VDUP1 has been observed in clinical specimens of ulcerative colitis (UC). However, the role of VDUP1 deficiency in colitis remains unclear. In this study, we investigated the role of VDUP1 in dextran sulfate sodium (DSS)-induced experimental colitis in mice. VDUP1-deficient mice were more susceptible to DSS-induced colitis than their wild-type (WT) littermates after 2% DSS administration. VDUP1-deficient mice exhibited an increased disease activity index (DAI) and histological scores, as well as significant colonic goblet cell loss and an increase in apoptotic cells. These changes were accompanied by a significant decrease in MUC2 mRNA expression and a marked increase in proinflammatory cytokines and chemokines within damaged tissues. Furthermore, phosphorylated NF-κB p65 expression was significantly upregulated in damaged tissues in the context of VDUP1 deficiency. VDUP1 deficiency also led to significant infiltration of macrophages into the site of ulceration. An in vitro chemotaxis assay confirmed that VDUP1 deficiency enhanced bone marrow-derived macrophage (BMDM) chemotaxis induced by CCL2. Overall, this study highlights VDUP1 as a regulator of UC pathogenesis and a potential target for the future development of therapeutic strategies.

Nonclinical toxicology studies with sodium taurodeoxycholate: acute and subacute toxicity in dogs.

Sodium taurodeoxycholate (TDCA) has been investigated for various inflammatory disorders such as sepsis. We recently evaluated nonclinical safety profile of TDCA using rats infused intravenously. As a series of preclinical safety investigations, we further conducted toxicity studies with TDCA delivered to dogs via intravenous administration under Good Laboratory Practice regulation in this study. In dose range-finding study (dose escalation study), dogs given with TDCA at a dose of 150 mg/kg showed marked changes in clinical signs, hematology, and serum biochemistry. And biochemical markers of liver damage and local skin lesions were observed following intravenous infusion of 100 mg/kg TDCA, suggesting that 100 mg/kg was chosen as the highest dose of TDCA for 4-week repeated-dose toxicity study using dogs. Despite no treatment-related significant changes in body weight, food consumption, ophthalmoscopy, and urinalysis, skin lesions were observed at the injection site of animals administered with higher than 50 mg/kg of TDCA along with biochemical and histopathological changes associated with liver injury. However, most of off-target effects were found to be reversible since these were recovered after stopping TDCA infusion. These findings indicate that the no-observed-adverse-effect-level (NOAEL) for TDCA in dogs was considered to be 5 mg/kg/d. Taken together, our results provide important toxicological profiles regarding the safe dose of TDCA for drug development or clinical application.

Topoisomerase IIIß Deficiency Induces Neuro-Behavioral Changes and Brain Connectivity Alterations in Mice.

Topoisomerase IIIß (Top3ß), the only dual-activity topoisomerase in mammals that can change topology of both DNA and RNA, is known to be associated with neurodevelopment and mental dysfunction in humans. However, there is no report showing clear associations of Top3ß with neuropsychiatric phenotypes in mice. Here, we investigated the effect of Top3ß on neuro-behavior using newly generated Top3ß deficient (Top3ß-/-) mice. We found that Top3ß-/- mice showed decreased anxiety and depression-like behaviors. The lack of Top3ß was also associated with changes in circadian rhythm. In addition, a clear expression of Top3ß was demonstrated in the central nervous system of mice. Positron emission tomography/computed tomography (PET/CT) analysis revealed significantly altered connectivity between many brain regions in Top3ß-/- mice, including the connectivity between the olfactory bulb and the cerebellum, the connectivity between the amygdala and the olfactory bulb, and the connectivity between the globus pallidus and the optic nerve. These connectivity alterations in brain regions are known to be linked to neurodevelopmental as well as psychiatric and behavioral disorders in humans. Therefore, we conclude that Top3ß is essential for normal brain function and behavior in mice and that Top3ß could be an interesting target to study neuropsychiatric disorders in humans.

Importin-11 is Essential for Normal Embryonic Development in Mice.

Importin-11 (Ipo11) is a novel member of the human importin family of transport receptors (karyopherins), which are known to mediate the nucleocytoplasmic transport of protein and RNA cargos. Despite its role in the transport of protein, we found that knockout of Ipo11 nuclear import factor affects normal embryonic development and govern embryo-lethal phenotypes in mice. In this study, we for the first time produced a mouse line containing null mutation in Ipo11 gene utilized by gene trapping. The Ipo11-/- embryos showed an embryonic lethal phenotype. The Ipo11-/- embryos showed a reduced size at embryonic day 10.5 (E10.5) when compared with Ipo11+/+ or Ipo11+/- embryos and died by E11.5. Whereas Ipo11+/- mice were healthy and fertile, and there was no detectable changes in embryonic lethality and phenotype when reviewed. In the X-gal staining with the Ipo11-/- or Ipo11+/- embryos, strong X-gal staining positivity was detected systematically in the whole mount embryos at E10.5, although almost no X-gal positivity was detected at E9.5, indicating that the embryos die soon after the process of Ipo11 expression started. These results indicate that Ipo11 is essential for the normal embryonic development in mice.

Critical Roles of E2F3 in Growth and Musculo-skeletal Phenotype in Mice.

E2F3, a member of the E2F family, plays a critical role in cell cycle and proliferation by targeting downstream, retinoblastoma (RB) a tumor suppressor family protein. The purpose of this study, was to investigate the role and function of E2F3 in vivo. We examined phenotypic abnormalities, by deletion of the E2f3 gene in mice. Complete ablation of the E2F3 was fully penetrant, in the pure C57BL/6N background. The E2f3+/ - mouse embryo developed normally without fatal disorder. However, they exhibited reduced body weight, growth retardation, skeletal imperfection, and poor grip strength ability. Findings suggest that E2F3 has a pivotal role in muscle and bone development, and affect normal mouse growth.

Cisplatin-induced ototoxicity involves interaction of PRMT3 and cannabinoid system.

This study investigated whether protein arginine methyltransferase (PRMT) and the cannabinoid system are involved in cisplatin-induced ototoxicity. Cisplatin increased cytosine-cytosine-adenosine-adenosine-thymidine-enhancer-binding protein homologous protein expression. This effect is indicative of an increase in endoplasmic reticulum (ER) stress, and apoptosis signaling including cleavage of caspase-3, caspase-9, poly-adenosine diphosphate-ribose polymerase, and phospho-p53, as well as expression of PRMT3, PRMT4 and fatty acid amide hydrolase (FAAH)1 in House Ear Institute-Organ of Corti 1 (HEI-OC1) cells. In addition, overexpression of PRMT3 or PRMT4 increased the expression of FAAH1 expression, apoptosis, and ER stress signaling in HEI-OC1 cells, whereas PRMT3 or PRMT4 knockdown had the opposite effect. Furthermore, overexpression of FAAH1 increased apoptosis and ER stress, but expression of the PRMTs was unchanged. In addition, a cannabinoid 1 receptor agonist and FAAH inhibitor attenuated apoptosis and ER stress, while cisplatin increased the binding of PRMT3 with FAAH1. In the in vivo experiments, cisplatin was injected intraperitoneally at 6 mg/kg/day into C57BL/6 mice, and 7 days later, this study confirmed that PRMT3 and PRMT4 were upregulated in the organ of Corti of the mice. These results indicate that cisplatin-induced ototoxicity was correlated with PRMT3, PRMT4 and the cannabinoid system, and PRMT3 binding with FAAH1 was increased by cisplatin in HEI-OC1 cells. Therefore, this study suggests that PRMT3 mediates cisplatin-induced ototoxicity via interaction with FAAH1 in vitro and in vivo.

Determination of Penicillium griseofulvum-oriented pyripyropene A, a selective inhibitor of acyl-coenzyme A:cholesterol acyltransferase 2, in mouse plasma using liquid chromatography-tandem mass spectrometry and its application to pharmacokinetic studies.

In this study, we developed a method for the determination of Penicillium griseofulvum-oriented pyripyropene A (PPPA), a selective inhibitor of acyl-coenzyme A:cholesterol acyltransferase 2, in mouse and human plasma and validated it using liquid chromatography-tandem mass spectrometry. Pyripyropene A (PPPA) and an internal standard, carbamazepine, were separated using a Xterra MS C18 column with a mixture of acetonitrile and 0.1% formic acid as the mobile phase. The ion transitions monitored in positive-ion mode [M + H]+ of multiple-reaction monitoring (MRM) were m/z 148.0 from m/z 584.0 for PPPA and m/z 194.0 from m/z 237.0 for the internal standard. The detector response was specific and linear for PPPA at concentrations within the range from 1 to 5,000 ng/mL. The intra-/inter-day precision and accuracy of the method was acceptable by the criteria for assay validation. The matrix effects of PPPA ranged from 97.6 to 104.2% and from 93.3 to 105.3% in post-preparative mouse and human plasma samples, respectively. PPPA was also stable under various processing and/or handling conditions. Finally, PPPA concentrations in the mouse plasma samples could be measured after intravenous, intraperitoneal, or oral administration of PPPA, suggesting that the assay is useful for pharmacokinetic studies on mice and applicable to human studies.

In vitro and in vivo safety studies of cinnamon extract (Cinnamomum cassia) on general and genetic toxicology.

Cinnamomum cassia has been widely used as a natural product to treat diseases in Asia due to its diverse pharmacological functions including anti-inflammatory, anti-oxidant, anti-microbial, anti-diabetic, and anti-tumor effects. Despite its ethnomedicinal benefits, little information regarding its toxicity is currently available. The aim of this study was to evaluate its potential long-term toxicity and genotoxicity in compliance with test guidelines of the Organization for Economic Cooperation and Development. A 13-week repeat-dose oral toxicity study revealed that body weights of rats were normal after receiving cinnamon extract at up to 2000 mg/kg. High-dose intake of cinnamon extract (2000 mg/kg) showed potential nephrotoxicity and hepatotoxicity to both males and females as evidenced by obvious increases of kidney/liver weight along with a small but statistically elevation of total cholesterol level. Overall findings from genetic toxicity testing battery including Ames test, in vitro mammalian cell micronucleus assay, and in vivo bone marrow micronucleus assay indicated that cinnamon extract was not mutagenic or clastogenic. In conclusion, cinnamon extract may possess potential nephrotoxicity and hepatotoxicity at dose higher than its recommended daily safe dose. Further study is needed to clarify the mechanism involved in its induction of liver and kidney injury.

Assessment of acute, 14-day, and 13-week repeated oral dose toxicity of Tiglium seed extract in rats.

BACKGROUND: Seed of mature Croton tiglium Linne, also known as Tiglium seed (TS), has been widely used as a natural product due to its several health beneficial properties including anti-tumor and antifungal activities. Despite its ethnomedicinal beneficial properties, toxicological information regarding TS extract, especially its long-term toxicity, is currently limited. Therefore, the objective of the present study was to evaluate acute and subchronic toxicity of TS extract in rats after oral administration following test guidelines of the Organization for Economic Cooperation and Development (OECD). METHODS: Toxicological properties of TS extract were evaluated by toxicity assays to determine its single-dose acute toxicity (125, 250, 500, 1000, or 2000 mg/kg), 14-day repeated-dose toxicity (125, 250, 500, 1000, or 2000 mg/kg) and 13-week repeated-dose toxicity (31.25, 62.5, 125, 250, and 500 mg/kg) in Sprague-Dawley rats and F344 rats. Hematological, serum biochemical, and histopathological parameters were analyzed to determine its median lethal dose (LD50) and no-observed-adverse-effect-level (NOAEL). RESULTS: Oral single dose up to 2000 mg/kg of TS extract resulted in no mortalities or abnormal clinical signs. In 13-week toxicity study, TS extract exhibited no dose-related changes (mortality, body weight, food/water consumption, hematology, clinical biochemistry, organ weight, or histopathology) at dose up to 500 mg/kg, the highest dosage level suggested based on 14-day repeat-dose oral toxicity study. CONCLUSION: Acute oral LD50 of TS extract in rats was estimated to be greater than 2000 mg/kg. NOAEL of TS extract administered orally was determined to be 500 mg/kg/day in both male and female rats. Results from these acute and subchronic toxicity assessments of TS extract under Good Laboratory Practice regulations indicate that TS extract appears to be safe for human consumption.

Genetically obese (ob/ob) mice are resistant to the lethal effects of thioacetamide hepatotoxicity.

Obesity increases the risk of chronic liver diseases, including viral hepatitis, alcohol-induced liver disease, and non-alcoholic steatohepatitis. In this study, we investigated the effects of obesity in acute hepatic failure using a murine model of thioacetamide (TA)-induced liver injury. Genetically obese ob/ob mice, together with non-obese ob/+ littermates, were subjected to a single intraperitoneal injection of TA, and examined for signs of hepatic injury. ob/ob mice showed a significantly higher survival rate, lower levels of serum alanine aminotransferase and aspartate aminotransferase, and less hepatic necrosis and apoptosis, compared with ob/+ mice. In addition, ob/ob mice exhibited significantly lower levels of malondialdehyde and significantly higher levels of glutathione and antioxidant enzyme activities compared with their ob/+ counterparts. Bioactivation analyses revealed reduced plasma clearance of TA and covalent binding of [(14)C]TA to liver macromolecules in ob/ob mice. Together, these data demonstrate that genetically obese mice are resistant to TA-induced acute liver injury through diminished bioactivation of TA and antioxidant effects.

Comparative toxicity and biodistribution assessments in rats following subchronic oral exposure to copper nanoparticles and microparticles.

BACKGROUND: Copper nanoparticles (Cu NPs) have great potential in electronics and biomedical fields because of their efficient thermodynamic and anti-microbial properties. However, their potential toxic effects and kinetic data following repeated exposure are still unclear. METHODS: We evaluated the physicochemical properties of Cu NPs (25 nm) and copper microparticles (Cu MPs, 14-25 µm). Comparative in vivo toxicity of Cu NPs and Cu MPs was evaluated by conducting a 28-day repeated oral dose study at equivalent dose levels of 0, 100, 200, and 400 mg/kg/day (vehicle, 1 % hydroxypropyl methylcellulose). We determined Cu levels in the blood, tissues, urine, and feces by using inductively coupled plasma mass spectrometry. RESULTS: The solubility of Cu NPs and Cu MPs was 84.5 and 17.2 %, respectively, in an acidic milieu; however, they scarcely dissolved in vehicle or intestinal milieus. The specific surface area of Cu NPs and Cu MPs was determined to be 14.7 and 0.16 m2/g, respectively. Cu NPs exhibited a dose-dependent increase of Cu content in the blood and tested organs, with particularly high levels of Cu in the liver, kidney, and spleen. Only for liver and kidney increased Cu levels were found in Cu MPs-treated rats. Cu NPs caused a dose-related increase in Cu levels in urine, whereas Cu MPs did not affect the urine Cu levels. Extremely high levels of Cu were detected in the feces of Cu MPs-treated rats, whereas much lower levels were detected in the feces of Cu NPs-treated rats. A comparative in vivo toxicity study showed that Cu NPs caused damages to red blood cells, thymus, spleen, liver, and kidney at ≥200 mg/kg/days, but Cu MPs did not cause any adverse effects even at the highest dose. CONCLUSIONS: Overall, the in vivo repeated dose toxicity study of Cu NPs and Cu MPs demonstrated that large surface area and high solubility in physiological milieus could directly influence the toxicological responses and biodistribution of Cu particles when administered orally. Under these experimental conditions, the no-observed-adverse-effect levels of Cu NPs and Cu MPs were determined to be 100 and ≥400 mg/kg/day, respectively.

Protective effects of diallyl disulfide on carbon tetrachloride-induced hepatotoxicity through activation of Nrf2.

This study was conducted to investigate the potential effects of diallyl disulfide (DADS) on carbon tetrachloride (CCl4 )-induced acute hepatotoxicity and to determine the molecular mechanisms of protection offered by DADS in rats. DADS was administered orally at 50 and 100 mg/kg/day once daily for 5 consecutive days prior to CCl4 administration. The single oral dose of CCl4 (2 mL/kg) caused a significant elevation in serum aspartate and alanine aminotransferase activities, which decreased upon pretreatment with DADS. Histopathological examinations showed extensive liver injury, characterized by extensive hepatocellular degeneration/necrosis, fatty changes, inflammatory cell infiltration, and congestion, which were reversed following pretreatment with DADS. The effects of DADS on cytochrome P450 2E1 (CYP2E1), the major isozyme involved in CCl4 bioactivation, were also investigated. DADS pretreatment resulted in a significant decrease in CYP2E1 protein levels in dose-dependent manner. In addition, CCl4 caused a decrease in protein level of cytoplasmic nuclear factor E2-related factor 2 (Nrf2) and suppression of nuclear translocation of Nrf2 concurrent with downregulation of detoxifying phase II enzymes and a decrease in antioxidant enzyme activities. In contrast, DADS prevented the depletion of cytoplasmic Nrf2 and enhanced nuclear translocation of Nrf2, which, in turn, upregulated antioxidant and/or phase II enzymes. These results indicate that the protective effects of DADS against CCl4 -induced hepatotoxicity possibly involve mechanisms related to its ability to induce antioxidant or detoxifying enzymes by activating Nrf2 and block metabolic activation of CCl4 by suppressing CYP2E1.

Thioredoxin-interacting protein mediates hepatic lipogenesis and inflammation via PRMT1 and PGC-1α regulation in vitro and in vivo.

BACKGROUND & AIMS: Non-alcoholic fatty liver disease (NAFLD) is strongly associated with obesity and type 2 diabetes. Thioredoxin-interacting protein (TXNIP) regulates the cellular redox state and metabolism and has been linked to many diseases, including diabetes. Therefore, we examined the role of TXNIP in hepatic steatosis in vitro and in vivo. METHODS: Lipogenic and inflammatory proteins produced by hepatocytes treated with palmitic acid (PA) or transfected with TXNIP or Txnip siRNA were measured by Western blotting. Lipid accumulation was assessed using Oil Red O staining. Protein interactions were assessed by immunoprecipitation and proximity ligation assay. Hepatic protein levels were measured by Western blotting from wild type or Txnip(-/-) mice fed a high-fat diet (HFD) or chow diet. Livers from NAFLD patients were compared with normal liver by immunohistochemistry. RESULTS: PA increased TXNIP, and inflammatory and lipogenic proteins in both AML12 and H4IIE cells. It also increased the peroxisome proliferator-activated receptor gamma co-activator-1α (PGC-1α), which mediated the expression of lipogenic markers and lipid accumulation. In addition, PA increased protein arginine methyltransferase-1 (PRMT1) and PRMT1 siRNA abolished the increase in lipogenic markers with PGC-1α. Furthermore, TXNIP interacted with PRMT1 in PA-treated hepatocytes. In vivo, levels of lipogenic proteins, inflammatory molecules, PGC-1α, and PRMT1 were increased in the livers of HFD mice compared with those fed a chow diet, and were ameliorated in HFD Txnip(-/-) mice. Moreover, TXNIP, PRMT1, and PGC-1α were elevated in the livers of human NAFLD patients. CONCLUSIONS: TXNIP mediates hepatic lipogenesis via PRMT1 and PGC-1α regulation and inflammation in vitro and in vivo, implying that targeting TXNIP and PRMT1 is a potential therapeutic approach for treatment of NAFLD.

Progression of breast cancer cells was enhanced by endocrine-disrupting chemicals, triclosan and octylphenol, via an estrogen receptor-dependent signaling pathway in cellular and mouse xenograft models.

In the present study, we determined whether two endocrine-disrupting chemicals (EDCs), triclosan (TCS) and octylphenol (OP), are able to alter the expression of two cell cycle regulators, cyclin D1 and p21, in both in vitro and mouse breast cancer models. In addition, we determined whether the stimulatory effects of OP or TCS on breast cancer progression may be associated with an estrogen receptor (ER)-mediated signaling pathway. Altered expressions of cyclin D1 and p21 were observed in MCF-7 human breast cancer cells treated with TCS and OP, which is linked to the G1/S transition of cell cycle, leading to cell proliferation. In a xenograft mouse model, breast tumor masses were established following exposure to TCS and OP for 8 weeks. In these animals, the tumor cells with BrdU-positive nuclei were increased by treatment with 17ß-estradiol (E2), OP, and TCS compared to that of a control (corn oil), suggesting that TCS and OP increase DNA synthesis during the S phase in tumor cells. Increased level of cyclin D1 protein by TCS and OP was also observed in vivo, implying that the effects of these EDCs possessing estrogenic activity alter the expression of genes related to cancer progression. It was of interest that the effects of TCS and OP were reversed by ICI 182,780, an ER antagonist, indicating that EDC-induced activities are mediated by an ER-dependent signaling pathway. Taken together, these results suggest that TCS and OP may promote breast cancer progression, via an ER-mediated signaling cascade.

Ameliorative effects of pine bark extract on spermatotoxicity by α-chlorohydrin in rats.

We investigated the protective effects of pine bark extract (Pycnogenol®, PYC, Horphag Research Ltd., Route de Belis, France) against α-chlorohydrin (ACH)-induced spermatotoxicity in rats. Rats were orally administered ACH (30 mg/kg/day) with or without PYC (20 mg/kg/day) for 7 days. Administration of ACH significantly decreased sperm motility. α-Chlorohydrin also caused histopathological alterations and apoptotic changes in caput epididymides. An increased malondialdehyde concentration and decreased glutathione content, as well as catalase and glutathione peroxidase activities were also found. In contrast, PYC treatment significantly prevented ACH-induced spermatotoxicity, including decreased sperm motility, histopathological lesions, and apoptotic changes in the caput epididymis. Pycnogenol® also had an antioxidant benefit by decreasing malondialdehyde and increasing levels of the antioxidant glutathione and the activities of the antioxidant enzymes catalase and peroxidase in epididymal tissues. These results indicate that PYC treatment attenuated ACH-induced spermatotoxicity through antioxidant and antiapoptotic effects.

Overexpression and ß-1,6-N-acetylglucosaminylation-initiated aberrant glycosylation of TIMP-1: a "double whammy" strategy in colon cancer progression.

There has been ongoing debate over whether tissue inhibitor of metalloproteinase-1 (TIMP-1) is pro- or anti-oncogenic. We confirmed that TIMP-1 reinforced cell proliferation in an αvß3 integrin-dependent manner and conferred resistance against cytotoxicity triggered by TNF-α and IL-2 in WiDr colon cancer cells. The cell-proliferative effects of TIMP-1 contributed to clonogenicity and tumor growth during the onset and early phase of tumor formation in vivo and in vitro. However, mass-produced TIMP-1 impeded further tumor growth by tightly inhibiting the activities of collagenases, which are critical for tumor growth and malignant transformation. Tumor cells could overcome this impasse by overexpression of N-acetylglucosaminyltransferase V, which deteriorates TIMP-1 into an aberrant glycoform. The aberrant glycoform of TIMP-1 was responsible for the mitigated inhibition of collagenases. The outbalanced activities of collagenases can degrade the basement membrane and the interstitial matrix, which act as a physical barrier for tumor growth and progression more efficiently. The concomitant overexpression of TIMP-1 and N-acetylglucosaminyltransferase V enabled WiDr cells to show a higher tumor growth rate as well as more malignant behaviors in a three-dimensional culture system.

Loss of Mel-18 enhances breast cancer stem cell activity and tumorigenicity through activating Notch signaling mediated by the Wnt/TCF pathway.

Mel-18 has been proposed as a negative regulator of Bmi-1, a cancer stem cell (CSC) marker, but it is still unclear whether Mel-18 is involved in CSC regulation. Here, we examined the effect of Mel-18 on the stemness of human breast CSCs. In Mel-18 small hairpin RNA (shRNA)-transduced MCF-7 cells, side population (SP) cells and breast CSC surface marker (CD44(+)/CD24(-)/ESA(+))-expressing cells, which imply a CSC population, were enriched. Moreover, the self-renewal of CSCs was enhanced by Mel-18 knockdown, as measured by the ability for tumorsphere formation in vitro and tumor-initiating capacity in vivo. Similarly, Mel-18 overexpression inhibited the number and self-renewal activity of breast CSCs in SK-BR-3 cells. Furthermore, our data showed that Mel-18 blockade up-regulated the expression of the Wnt/TCF target Jagged-1, a Notch ligand, and consequently activated the Notch pathway. Pharmacologic inhibition of the Notch and Wnt pathways abrogated Mel-18 knockdown-mediated tumorsphere formation ability. Taken together, our findings suggest that Mel-18 is a novel negative regulator of breast CSCs that inhibits the stem cell population and in vitro and in vivo self-renewal through the inactivation of Wnt-mediated Notch signaling.

Peroxiredoxin 2 deficiency exacerbates atherosclerosis in apolipoprotein E-deficient mice.

RATIONALE: Peroxiredoxin 2 (Prdx2), a thiol-specific peroxidase, has been reported to regulate proinflammatory responses, vascular remodeling, and global oxidative stress. OBJECTIVE: Although Prdx2 has been proposed to retard atherosclerosis development, no direct evidence and mechanisms have been reported. METHODS AND RESULTS: We show that Prdx2 is highly expressed in endothelial and immune cells in atherosclerotic lesions and blocked the increase of endogenous H(2)O(2) by atherogenic stimulation. Deficiency of Prdx2 in apolipoprotein E-deficient (ApoE(-/-)) mice accelerated plaque formation with enhanced activation of p65, c-Jun, JNKs, and p38 mitogen-activated protein kinase; and these proatherogenic effects of Prdx2 deficiency were rescued by administration of the antioxidant ebselen. In bone marrow transplantation experiments, we found that Prdx2 has a major role in inhibiting atherogenic responses in both vascular and immune cells. Prdx2 deficiency resulted in increased expression of vascular adhesion molecule-1, intercellular adhesion molecule-1, and monocyte chemotactic protein-1, which led to increased immune cell adhesion and infiltration into the aortic intima. Compared with deficiency of glutathione peroxidase 1 or catalase, Prdx2 deficiency showed a severe predisposition to develop atherosclerosis. CONCLUSIONS: Prdx2 is a specific peroxidase that inhibits atherogenic responses in vascular and inflammatory cells, and specific activation of Prdx2 may be an effective means of antiatherogenic therapy.

Vitamin D3 upregulated protein 1 deficiency promotes N-methyl-N-nitrosourea and Helicobacter pylori-induced gastric carcinogenesis in mice.

OBJECTIVE: Vitamin D(3) upregulated protein 1 (VDUP1) is a potent tumour suppressor whose expression is dramatically reduced in various types of human cancers, including gastric cancer. However, the precise mechanisms underlying tumour development remain unclear. In the present study, the authors examined the effect of VDUP1 on Helicobacter pylori-induced gastric carcinogenesis in mice. DESIGN: Gastric cancer was generated in VDUP1 knockout (KO) and wild-type mice using a combination of N-methyl-N-nitrosourea treatment and H pylori infection. Fifty weeks after treatment, gastric tissues from both types of mice were examined by histopathology, immunohistochemistry and immunoblotting. In vitro tests on the human gastric cancer cell line, AGS, were also performed to identify the underlying mechanisms of cancer development. RESULTS: The overall incidence of gastric cancer was significantly higher in VDUP1 KO mice than in wild-type mice. Similarly, VDUP1 KO mice showed more severe chronic gastritis, glandular atrophy, foveolar hyperplasia, metaplasia and dysplasia. Although no differences in the apoptotic index were apparent, lack of VDUP1 increased the rate of gastric epithelial cell proliferation in non-cancerous stomachs, with corresponding increases in tumour necrosis factor alpha (TNFα) level, nuclear transcription factor kappa B (NF-κB) activation and cyclooxygenase-2 (COX-2) expression. An in vitro study showed that H pylori-associated cell proliferation and induction of TNFα, NF-κB and COX-2 were inhibited in cells transfected with VDUP1. In addition, overexpression of VDUP1 in AGS cells suppressed TNFα-induced NF-κB activation and COX-2 expression. CONCLUSION: Our data show that VDUP1 negatively regulates H pylori-associated gastric carcinogenesis, in part by disrupting cell growth and inhibiting the induction of TNFα, NF-κB and COX-2. These findings provide important insights into the role of VDUP1 in H pylori-associated tumourigenesis.

Vitamin D3 upregulated protein 1 suppresses TNF-α-induced NF-κB activation in hepatocarcinogenesis.

Vitamin D(3) upregulated protein 1 (VDUP1) is a candidate tumor suppressor, the expression of which is dramatically reduced in various tumor tissues. In this study, we found that VDUP1 expression is suppressed during human hepatic carcinogenesis, and mice lacking VDUP1 are much more susceptible to diethylnitrosamine-induced hepatocarcinogenesis compared with wild type mice. VDUP1-deficient tumors proliferated significantly more than wild type tumors and had corresponding changes in the expression of key cell cycle regulatory proteins. In addition, the hepatomitogen-induced response was associated with a considerable increase in the release of TNF-α and subsequent enhancement of NF-κB activation in VDUP1-deficient mice. When cells were treated with TNF-α, the VDUP1 level was markedly reduced, concomitant with elevated NF-κB activation. Furthermore, the overexpression of VDUP1 resulted in the robust suppression of TNF-α-activated NF-κB activity via association with HDAC1 and HDAC3. These results indicate that VDUP1 negatively regulates hepatocarcinogenesis by suppressing TNF-α-induced NF-κB activation.