Browsing by Author "Klaunig, James E."
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Item A computational model of liver tissue damage and repair(Public Library of Science, 2020-12-21) Adhyapok, Priyom; Fu, Xiao; Sluka, James P.; Clendenon, Sherry G.; Sluka, Victoria D.; Wang, Zemin; Dunn, Kenneth; Klaunig, James E.; Glazier, James A.; Medicine, School of MedicineDrug induced liver injury (DILI) and cell death can result from oxidative stress in hepatocytes. An initial pattern of centrilobular damage in the APAP model of DILI is amplified by communication from stressed cells and immune system activation. While hepatocyte proliferation counters cell loss, high doses are still lethal to the tissue. To understand the progression of disease from the initial damage to tissue recovery or death, we computationally model the competing biological processes of hepatocyte proliferation, necrosis and injury propagation. We parametrize timescales of proliferation (α), conversion of healthy to stressed cells (β) and further sensitization of stressed cells towards necrotic pathways (γ) and model them on a Cellular Automaton (CA) based grid of lattice sites. 1D simulations show that a small α/β (fast proliferation), combined with a large γ/β (slow death) have the lowest probabilities of tissue survival. At large α/β, tissue fate can be described by a critical γ/β* ratio alone; this value is dependent on the initial amount of damage and proportional to the tissue size N. Additionally, the 1D model predicts a minimum healthy population size below which damage is irreversible. Finally, we compare 1D and 2D phase spaces and discuss outcomes of bistability where either survival or death is possible, and of coexistence where simulated tissue never completely recovers or dies but persists as a mixture of healthy, stressed and necrotic cells. In conclusion, our model sheds light on the evolution of tissue damage or recovery and predicts potential for divergent fates given different rates of proliferation, necrosis, and injury propagation.Item Antioxidant vitamin C prevents decline in endothelial function during sitting(International Scientific Information, 2015-04-07) Thosar, Saurabh S.; Bielko, Sylvanna L.; Wiggins, Chad S.; Klaunig, James E.; Mather, Kieren J.; Wallace, Janet P.; Department of Kinesiology, School of Physical Education and Tourism ManagementBACKGROUND: This study was designed to test the hypothesis that antioxidant Vitamin C prevents the impairment of endothelial function during prolonged sitting. MATERIAL AND METHODS: Eleven men (24.2 ± 4.4 yrs) participated in 2 randomized 3-h sitting trials. In the sitting without vitamin C (SIT) and the sitting with vitamin C (VIT) trial, participants were seated for 3 h without moving their legs. Additionally, in the VIT trial, participants ingested 2 vitamin C tablets (1 g and 500 mg) at 30 min and 1 h 30 min, respectively. Superficial femoral artery (SFA) flow-mediated dilation (FMD) was measured hourly for 3 h. RESULTS: By a 1-way ANOVA, there was a significant decline in FMD during 3 h of SIT (p<0.001). Simultaneously, there was a significant decline in antegrade (p=0.04) and mean (0.037) shear rates. For the SIT and VIT trials by a 2-way (trial x time) repeated measures ANOVA, there was a significant interaction (p=0.001). Pairwise testing revealed significant between-SFA FMD in the SIT and VIT trial at each hour after baseline, showing that VIT prevented the decline in FMD 1 h (p=0.009), 2 h (p=0.016), and 3 h (p=0.004). There was no difference in the shear rates between SIT and VIT trials (p>0.05). CONCLUSIONS: Three hours of sitting resulted in impaired SFA FMD. Antioxidant Vitamin C prevented the decline in SFA FMD, suggesting that oxidative stress may contribute to the impairment in endothelial function during sitting.Item Contribution of Environment and Genetics to Pancreatic Cancer Susceptibility(Public Library of Science, 2014-03-20) Hocevar, Barbara A.; Kamendulis, Lisa M.; Pu, Xinzhu; Perkins, Susan M.; Wang, Zheng-Yu; Johnston, Erica L.; DeWitt, John M.; Li, Lang; Loehrer, Patrick J.; Klaunig, James E.; Chiorean, E. Gabriela; Medicine, School of MedicineSeveral risk factors have been identified as potential contributors to pancreatic cancer development, including environmental and lifestyle factors, such as smoking, drinking and diet, and medical conditions such as diabetes and pancreatitis, all of which generate oxidative stress and DNA damage. Oxidative stress status can be modified by environmental factors and also by an individual's unique genetic makeup. Here we examined the contribution of environment and genetics to an individual's level of oxidative stress, DNA damage and susceptibility to pancreatic cancer in a pilot study using three groups of subjects: a newly diagnosed pancreatic cancer group, a healthy genetically-unrelated control group living with the case subject, and a healthy genetically-related control group which does not reside with the subject. Oxidative stress and DNA damage was evaluated by measuring total antioxidant capacity, direct and oxidative DNA damage by Comet assay, and malondialdehyde levels. Direct DNA damage was significantly elevated in pancreatic cancer patients (age and sex adjusted mean ± standard error: 1.00±0.05) versus both healthy unrelated and related controls (0.70±0.06, p<0.001 and 0.82±0.07, p = 0.046, respectively). Analysis of 22 selected SNPs in oxidative stress and DNA damage genes revealed that CYP2A6 L160H was associated with pancreatic cancer. In addition, DNA damage was found to be associated with TNFA −308G>A and ERCC4 R415Q polymorphisms. These results suggest that measurement of DNA damage, as well as select SNPs, may provide an important screening tool to identify individuals at risk for development of pancreatic cancer.Item Dysbiosis in gastrointestinal pathophysiology: Role of the gut microbiome in Gulf War Illness(Wiley, 2023) Slevin, Elise; Koyama, Sachiko; Harrison, Kelly; Wan, Ying; Klaunig, James E.; Wu, Chaodong; Shetty, Ashok K.; Meng, Fanyin; Medicine, School of MedicineGulf War Illness (GWI) has been reported in 25%-35% of veterans returned from the Gulf war. Symptoms of GWI are varied and include both neurological and gastrointestinal symptoms as well as chronic fatigue. Development of GWI has been associated with chemical exposure particularly with exposure to pyridostigmine bromide (PB) and permethrin. Recent studies have found that the pathology of GWI is connected to changes in the gut microbiota, that is the gut dysbiosis. In studies using animal models, the exposure to PB and permethrin resulted in similar changes in the gut microbiome as these found in GW veterans with GWI. Studies using animal models have also shown that phytochemicals like curcumin are beneficial in reducing the symptoms and that the extracellular vesicles (EV) released from gut bacteria and from the intestinal epithelium can both promote diseases and suppress diseases through the intercellular communication mechanisms. The intestinal epithelium cells produce EVs and these EVs of intestinal epithelium origin are found to suppress inflammatory bowel disease severity, suggesting the benefits of utilizing EV in treatments. On the contrary, EV from the plasma of septic mice enhanced the level of proinflammatory cytokines in vitro and neutrophils and macrophages in vivo, suggesting differences in the EV depending on the types of cells they were originated and/or influences of environmental changes. These studies suggest that targeting the EV that specifically have positive influences may become a new therapeutic strategy in the treatment of veterans with GWI.Item Effect of different obesogenic diets on pancreatic histology in Ossabaw miniature swine(Wolters Kluwer, 2011-04) Fullenkamp, Allison M.; Bell, Lauren N.; Robbins, Reiesha D.; Lee, Lydia; Saxena, Romil; Alloosh, Mouhamad; Klaunig, James E.; Mirmira, Raghavendra G.; Sturek, Michael; Chalasani, Naga; Department of Medicine, IU School of MedicineOBJECTIVE: Obesity is a factor in the outcome and severity of pancreatic conditions. We examined the effect of hypercaloric diets on the pancreata of Ossabaw swine, a large animal model of metabolic syndrome and obesity. METHODS: Swine were fed with 1 of 4 diets: high-fructose (n = 9), atherogenic (n = 10), modified atherogenic (n = 6), or eucaloric standard diet (n = 12) for 24 weeks. Serum chemistries were measured, and pancreata were examined for histological abnormalities including steatosis, inflammation or fibrosis, insulin content, and oxidative stress. RESULTS: The fructose, atherogenic, and modified atherogenic diet groups exhibited obesity, metabolic syndrome, islet enlargement, and significantly increased pancreatic steatosis (22.9% ± 7.5%, 19.7% ± 7.7%, and 38.7% ± 15.3% fat in total tissue area, respectively) compared with controls (9.3% ± 1.9%; P < 0.05). The modified atherogenic diet group showed significantly increased oxidative stress levels as evidenced by elevated serum malondialdehyde (3.0 ± 3.3 vs 1.5 ± 0.3 μmol/L in controls; P = 0.006) and pancreatic malondialdehyde (0.1 ± 0.12 vs 0.04 ± 0.01 nmol/mg protein in controls; P = 0.01). None of the swine exhibited pancreatitis or cellular injury. CONCLUSIONS: Ossabaw swine fed with a modified atherogenic diet developed significant pancreatic steatosis and increased oxidative stress, but no other histological abnormalities were observed.Item Effect of oral methyl-t-butyl ether (MTBE) on the male mouse reproductive tract and oxidative stress in liver(Elsevier, 2008) de Peyster, Ann; Rodriguez, Yvonne; Shuto, Rika; Goldberg, Beck; Gonzales, Frank; Pu, Xinzhu; Klaunig, James E.; Department of Pharmacology and Toxicology, IU School of MedicineMTBE is found in water supplies used for drinking and other purposes. These experiments follow up on earlier reports of reproductive tract alterations in male mice exposed orally to MTBE and explored oxidative stress as a mode of action. CD-1 mice were gavaged with 400–2000 mg/kg MTBE on days 1, 3, and 5, injected ip with hCG (2.5 IU/g) on day 6, and necropsied on day 7. No effect was seen in testis histology or testosterone levels. Using a similar dosing protocol, others had initially reported disruption of seminiferous tubules in MTBE–gavaged mice, although later conclusions published were consistent with our findings. Another group had also reported testicular and other reproductive system abnormalities in male BALB/c mice exposed for 28 days to 80–8000 ug/ml MTBE in drinking water. We gave these MTBE concentrations to adult mice for 28 days and juvenile mice for 51 days through PND 77. Evidence of oxidative stress was examined in liver homogenates from the juvenile study using MDA, TEAC and 8OH2hG as endpoints. MTBE exposures at the levels examined indicated no significant changes in the male mouse reproductive tract and no signs of hepatic oxidative stress. This appears to be the first oral MTBE exposure of juvenile animals, and also the first to examine potential for MTBE to cause oxidative stress in vivo using a typical route of human exposure.Item Effects of choline kinase activity on phospholipid metabolism and malignant phenotype of prostate cancer cells(2010-10) Bansal, Aditya; DeGrado, Timothy R.; Harris, Robert A. (Robert Allison), 1939-; Bosron, William F.; Klaunig, James E.High choline uptake and increased choline kinase activity have been reported in many cancers. This has motivated the use of choline as a biomarker for tumor imaging. Tumors in general are heterogeneous in nature with respect to oxygen tension. There are regions of hypoxia and normoxia that are expected to have different metabolism but regulation of choline metabolism under hypoxia is poorly understood. It is important to clarify the status of choline metabolism in hypoxic microenvironment as it will have an impact on potential of choline as a cancer biomarker. The primary goal was to determine the status of choline phosphorylation in hypoxic cancer cells and its effect on uptake of choline. This was examined by tracer studies in cancer cells exposed to hypoxia. It was observed that hypoxia universally inhibits choline uptake /phosphorylation in cancer cells. Decreased choline phosphorylation resulted in transient uptake of choline radiotracers in cultured cancer cells and 9L tumors suggesting potential problem in using choline as a biomarker for cancers in hypoxic microenvironment. To investigate the mechanism behind decrease in choline phosphorylation, steady state levels of choline metabolites were measured and choline kinase catalyzed choline phosphorylation step was found to be rate-limiting in PC-3 cells. This suggested that modulation in choline kinase levels can alter choline metabolism in hypoxic cancer cells. Expression and activity assays for choline kinase revealed that choline kinase expression is down-regulated in hypoxia. This regulation involved transcriptional level mediation by HIF1 at the conserved HRE7 site in choline kinase promoter. To further understand the importance of down-regulation of choline kinase in hypoxia, stable prostate cancer cell lines over-expressing choline kinase were generated. Effect of over-expression of choline kinase in hypoxia was evaluated in terms of malignant phenotypes like proliferation rate, anchorage independent growth and invasion potential. Both over-expression of choline kinase and hypoxia had a pronounced effect on malignant phenotypes of prostate cancer cells. Further study showed that increased choline kinase activity and hypoxic tumor microenvironment are important for progression of early-stage, androgen-dependent LNCaP prostate cancer cells but confer little survival advantage in undifferentiated, androgen-independent PC-3 prostate cancer cells.Item Endothelial dysfunction in pathological processes of chronic liver disease during aging(Wiley, 2022) Wan, Ying; Li, Xuedong; Slevin, Elise; Harrison, Kelly; Li, Tian; Zhang, Yudian; Klaunig, James E.; Wu, Chaodong; Shetty, Ashok K.; Dong, X. Charlie; Meng, Fanyin; Medicine, School of MedicineAging is associated with gradual changes in liver structure and physiological/pathological functions in hepatic cells including hepatocytes, cholangiocytes, Kupffer cells, hepatic stellate cells (HSCs), and liver sinusoidal endothelial cells (LSECs). LSECs are specialized hepatic endothelial cells that regulate liver homeostasis. These cells actively impact the hepatic microenvironment as they have fenestrations and a thin morphology to allow substance exchange between circulating blood and the liver tissue. As aging occurs, LSECs have a reduction in both the number and size of fenestrations, which is referred to as pseudocapillarization. This along with the aging of the liver leads to increased oxidative stress, decreased availability of nitric oxide, decreased hepatic blood flow, and increased inflammatory cytokines in LSECs. Vascular aging can also lead to hepatic hypoxia, HSC activation, and liver fibrosis. In this review, we described the basic structure of LSECs, and the effect of LSECs on hepatic inflammation and fibrosis during aging process. We briefly summarized the changes of hepatic microcirculation during liver inflammation, the effect of aging on the clearance function of LSECs, the interactions between LSECs and immunity, hepatocytes or other hepatic nonparenchymal cells, and the therapeutic intervention of liver diseases by targeting LSECs and vascular system. Since LSECs play an important role in the development of liver fibrosis and the changes of LSEC phenotype occur in the early stage of liver fibrosis, the study of LSECs in the fibrotic liver is valuable for the detection of early liver fibrosis and the early intervention of fibrotic response.Item Estrogenic Activity of the Polybrominated Diphenyl Ether Flame Retardant Mixture DE-71(2008-03-05T20:08:04Z) Mercado-Feliciano, Minerva; Bigsby, Robert M.; Klaunig, James E.; Jeng, Meei-Huey; Kamendulis, Lisa; Skaar, Todd; Sullivan, William J., Jr.Polybrominated diphenyl ethers (PBDEs) are widely used flame retardants suspected to act as endocrine disruptors. We tested the commercial PBDE mixture DE-71 and its in vivo metabolites for estrogenic activity. MCF-7 breast cancer cells culture, ERE-luciferase gene expression, 3H-β-estradiol displacement from recombinant ERα, and ovariectomized (OVX) mice served as bioassays. Although DE-71 did not bind ERα, it was able to increase MCF-7 cell proliferation and this was prevented by the antiestrogen fulvestrant. DE-71 co-treatment reduced the effect of estradiol in MCF-7 cells. In the OVX mouse (BALB/c) 3-day assay, DE-71 administered alone had no effect on uterine or vaginal tissues but when administered subcutaneously potentiated estradiol’s effect on uterine weight in a dose-dependent manner. DE-71 administered SQ to BALB/c mice for 34 days slightly increased uterine epithelial height (UEH), vaginal epithelial thickness (VET) and mammary ductal lumen area, and attenuated the estradiol-induced increase in UEH; these effects were not seen in C57BL/6 mice. DE-71 increased liver weight in BALB/c, C57BL/6 and estrogen receptor-alpha knockout (ERαKO) mice. Liver cytochrome P450 1A (CYP1A) and CYP2B activities increased 2.5-fold and 7-fold respectively when DE-71 was administered PO, but only CYP2B increased (5-fold) after SQ treatment. Six OH-PBDE metabolites were found in mice after 34-day DE-71 treatment and all were able to bind recombinant ERα. Para-hydroxylated metabolites displayed a 10- to 30-fold higher affinity for ERα compared to ortho-hydroxylated PBDEs. Para-OH-PBDEs induced ERE-luciferase and produced an additive effect when coadministered with β-estradiol. DE-71 was also additive with β-estradiol. At high concentrations (≥ 5x10-5 M), ortho-OH-PBDEs were antiestrogenic in the ERE-luciferase assay. In conclusion, DE-71 behaves as a weak estrogen in both MCF-7 breast cancer cells and ovariectomized adult mice. Mice strain, treatment route and duration determined if DE-71 was estrogenic. BALB/c mice are more susceptible to DE-71 effects in estrogen target tissues than C57BL/6 mice. DE-71 increased liver weight, 5%-51% depending on mouse strain and treatment regime, independently of ERα. The observations that the DE-71 mixture does not displace 3H-β-estradiol from ERα while the hydroxylated metabolites do, suggest that the cellular and tissue effects were due to a metabolic activation of individual congeners.Item Evaluation of Storage Conditions for Assessing DNA Damage Using the Comet Assay(2006-11-02T14:25:05Z) Villavicencio, Dante; Klaunig, James E.; Kamendulis, Lisa M.; Willis, Lynn R.The single cell gel electrophoresis assay (comet assay) is a useful tool for monitoring individuals who may be at risk of DNA damage and the ensuing process of carcinogenesis or other disease states. Leukocytes in blood samples provide a means of obtaining cells for use in the comet assay. However instances may arise when samples must be stored for later analysis. The present study investigated the effects of storage conditions on DNA damage in the form of strand breaks and oxidized bases in rat and human leukocytes using the comet assay. Whole blood and buffy coat samples were stored at room temperature or 4ºC for 1, 2, 24, and 48 hours or cryopreserved at -80ºC for 1 day and 1, 2, 3, and 4 weeks. The results show that the time of storage is limited if the whole blood or buffy coat samples are stored at room temperature or 4ºC. However, if cryopreserved using glycerol or DMSO as the cryoprotectant, the samples may be stored for at least 4 weeks without DNA strand breaks or oxidative damage deviating significantly from the fresh samples.