Tumor aggressiveness is independent of radiation quality in murine hepatocellular carcinoma and mammary tumor models.

PURPOSE: Estimating cancer risk associated with interplanetary space travel is complicated. Human exposure data to high atomic number, high-energy (HZE) radiation is lacking, so data from low linear energy transfer (low-LET) γ-ray radiation is used in risk models, with the assumption that HZE and γ-ray radiation have comparable biological effects. This assumption has been challenged by reports indicating that HZE radiation might produce more aggressive tumors. The goal of this research is to test whether high-LET HZE radiation induced tumors are more aggressive. MATERIALS AND METHODS: Murine models of mammary and liver cancer were used to compare the impact of exposure to 0.2Gy of 300MeV/n silicon ions, 3 Gy of γ-rays or no radiation. Numerous measures of tumor aggressiveness were assessed. RESULTS: For the mammary cancer models, there was no significant change in the tumor latency or metastasis in silicon-irradiated mice compared to controls. For the liver cancer models, we observed an increase in tumor incidence but not tumor aggressiveness in irradiated mice. CONCLUSION: Tumors in the HZE-irradiated mice were not more aggressive than those arising from exposure to low-LET γ-rays or spontaneously. Thus, enhanced aggressiveness does not appear to be a uniform characteristic of all tumors in HZE-irradiated animals.

B cells infected with Type 2 Epstein-Barr virus (EBV) have increased NFATc1/NFATc2 activity and enhanced lytic gene expression in comparison to Type 1 EBV infection.

Humans are infected with two distinct strains (Type 1 (T1) and Type 2 (T2)) of Epstein-Barr virus (EBV) that differ substantially in their EBNA2 and EBNA 3A/B/C latency genes and the ability to transform B cells in vitro. While most T1 EBV strains contain the "prototype" form of the BZLF1 immediate-early promoter ("Zp-P"), all T2 strains contain the "Zp-V3" variant, which contains an NFAT binding motif and is activated much more strongly by B-cell receptor signalling. Whether B cells infected with T2 EBV are more lytic than cells infected with T1 EBV is unknown. Here we show that B cells infected with T2 EBV strains (AG876 and BL5) have much more lytic protein expression compared to B cells infected with T1 EBV strains (M81, Akata, and Mutu) in both a cord blood-humanized (CBH) mouse model and EBV-transformed lymphoblastoid cell lines (LCLs). Although T2 LCLs grow more slowly than T1 LCLs, both EBV types induce B-cell lymphomas in CBH mice. T1 EBV strains (M81 and Akata) containing Zp-V3 are less lytic than T2 EBV strains, suggesting that Zp-V3 is not sufficient to confer a lytic phenotype. Instead, we find that T2 LCLs express much higher levels of activated NFATc1 and NFATc2, and that cyclosporine (an NFAT inhibitor) and knockdown of NFATc2 attenuate constitutive lytic infection in T2 LCLs. Both NFATc1 and NFATc2 induce lytic EBV gene expression when combined with activated CAMKIV (which is activated by calcium signaling and activates MEF2D) in Burkitt Akata cells. Together, these results suggest that B cells infected with T2 EBV are more lytic due to increased activity of the cellular NFATc1/c2 transcription factors in addition to the universal presence of the Zp-V3 form of BZLF1 promoter.

Maternal iron nutriture modulates placental development in a rat model of fetal alcohol spectrum disorder.

Prenatal alcohol exposure (PAE) causes developmental abnormalities known as fetal alcohol spectrum disorder (FASD). Maternal iron status modulates the severity of these defects in the offspring. Because the placenta is central in supporting fetal development, we investigated whether maternal iron status similarly modulates alcohol's effects in the placenta. We hypothesized that PAE causes placental insufficiency by decreasing placental weight and efficiency, and we hypothesized that these are worsened by maternal iron deficiency (ID) and alleviated by dietary iron fortification (IF). We also determined whether altered placental iron flux and inflammatory balance contribute to placental insufficiency. Pregnant Long-Evans rats consumed an iron-deficient (ID; 2-6 ppm), iron-sufficient (IS; 100 ppm), or iron-fortified (IF; 500 ppm) diet. Alcohol (5 g/kg body weight) or isocaloric maltodextrin (MD) was gavaged daily from gestational day (GD) 13.5-19.5. Placental outcomes were evaluated on GD20.5. PAE reduced fetal weight (p < 0.0001), placental weight (p = 0.0324), and placental efficiency (p = 0.0043). PAE downregulated placental transferrin receptor (p = 0.0032); it also altered placental Il1b and Tnf expression and the Il6:Il10 ratio (p = 0.0337, 0.0300, and 0.0034, respectively) to generate a response favoring inflammation. ID-PAE further reduced fetal growth and placental efficiency and induced a heightened pro-inflammatory placental profile. IF did not rescue the alcohol-reduced fetal weight, but it normalized placental efficiency and decreased placental inflammation. These placental cytokines correlated with fetal and placental growth, and explained 45% of the variability in fetal weight and 20% of the variability in placental efficiency. In summary, alcohol induces placental insufficiency and is associated with a pro-inflammatory cytokine profile exacerbated by maternal ID and mitigated by maternal IF. Because the placenta is closely linked to intrauterine growth, the placental insufficiency reported here may correlate with the lower birth weights in a subgroup of individuals who experienced PAE.

Alcohol's Dysregulation of Maternal-Fetal IL-6 and p-STAT3 Is a Function of Maternal Iron Status.

BACKGROUND: Prenatal alcohol exposure (PAE) causes long-term growth and neurodevelopmental deficits that are worsened by maternal iron deficiency (ID). In our preclinical rat model, PAE causes fetal anemia, brain ID, and elevated hepatic iron via increased maternal and fetal hepcidin synthesis. These changes are normalized by a prenatal iron-fortified (IF) diet. Here, we hypothesize that iron status and PAE dysregulate the major upstream pathways that govern hepcidin production-EPO/BMP6/SMAD and IL-6/JAK2/STAT3. METHODS: Pregnant, Long Evans rat dams consumed ID (2 to 6 ppm iron), iron-sufficient (IS, 100 ppm iron), or IF (500 ppm iron) diets and received alcohol (5 g/kg) or isocaloric maltodextrin daily from gestational days (GD) 13.5 to 19.5. Protein and gene expression were quantified in the 6 experimental groups at GD 20.5. RESULTS: PAE did not affect Epo or Bmp6 expression, but reduced p-SMAD1/5/8/SMAD1/5/8 protein ratios in both IS and ID maternal and fetal liver (all p's < 0.01). In contrast, PAE stimulated maternal hepatic expression of Il-6 (p = 0.03) and elevated p-STAT3/STAT3 protein ratios in both IS and ID maternal and fetal liver (all p's < 0.02). PAE modestly elevated maternal Il-1ß, Tnf-α, and Ifn-γ. Fetal cytokine responses to PAE were muted compared with dams, and PAE did not affect hepatic Il-6 (p = 0.78) in IS and ID fetuses. Dietary iron fortification sharply attenuated Il-6 expression in response to PAE, with IF driving a 150-fold decrease (p < 0.001) in maternal liver and a 10-fold decrease (p < 0.01) in fetal liver. The IF diet also normalized p-STAT3/STAT3 ratios in both maternal and fetal liver. CONCLUSIONS: These findings suggest that alcohol-driven stimulation of the IL-6/JAK2/STAT3 pathway mediates the elevated hepcidin observed in the PAE dam and fetus. Normalization of these signals by IF suggests that dysregulated hepcidin is driven by alcohol's disruption of the IL-6/JAK2/STAT3 pathway. Prenatal dietary IF represents a potential therapeutic approach for PAE that warrants further investigation.

Dietary Iron Fortification Normalizes Fetal Hematology, Hepcidin, and Iron Distribution in a Rat Model of Prenatal Alcohol Exposure.

BACKGROUND: Prenatal alcohol exposure (PAE) causes neurodevelopmental disability. Clinical and animal studies show gestational iron deficiency (ID) exacerbates PAE's behavioral and growth deficits. In rat, PAE manifests an inability to establish iron homeostasis, increasing hepcidin (maternal and fetal), and fetal liver iron while decreasing brain iron and promoting anemia. Here, we hypothesize dietary iron fortification during pregnancy may mitigate alcohol's disruption of fetal iron homeostasis. METHODS: Pregnant Long-Evans rats, fed iron-sufficient (100 ppm iron) or iron-fortified (IF; 500 ppm iron) diets, received either 5 g/kg alcohol (PAE) or isocaloric maltodextrin daily on gestational days (GD) 13.5 through 19.5. Maternal and fetal outcomes were evaluated on GD20.5. RESULTS: PAE reduced mean fetal weight (p < 0.001) regardless of maternal iron status, suggesting iron fortification did not improve fetal growth. Both PAE (p < 0.01) and IF (p = 0.035) increased fetal liver iron. In fetal brain, PAE (p = 0.015) affected total (p < 0.001) and nonheme iron (p < 0.001) such that iron fortification normalized (p = 0.99) the alcohol-mediated reductions in brain iron and nonheme iron. Iron fortification also improved fetal hematologic indices in PAE including hemoglobin, hematocrit, and mean cell volume (ps<0.001). Iron fortification also normalized hepcidin expression in alcohol-exposed maternal and fetal liver. Neither diet nor PAE affected transferrin (Tf) and ferritin (FTN) content in fetal liver, nor Tf or transferrin receptor in fetal brain. However, IF-PAE fetal brains trended to less FTN content (p = 0.074), suggesting greater availability of nonstorage iron. In PAE, hepcidin levels were linearly related to increased liver iron stores and decreased red blood cell count and brain iron. CONCLUSIONS: Maternal oral iron fortification mitigated PAE's disruption of fetal iron homeostasis and improved brain iron content, hematologic indices, and hepcidin production in this rat PAE model. Clinical studies show maternal ID substantially enhances fetal vulnerability to PAE, and our work supports increased maternal dietary iron intake may improve fetal iron status in alcohol-exposed pregnancies.

Latent Membrane Protein 1 (LMP1) and LMP2A Collaborate To Promote Epstein-Barr Virus-Induced B Cell Lymphomas in a Cord Blood-Humanized Mouse Model but Are Not Essential.

Epstein-Barr virus (EBV) infection is associated with B cell lymphomas in humans. The ability of EBV to convert human B cells into long-lived lymphoblastoid cell lines (LCLs) in vitro requires the collaborative effects of EBNA2 (which hijacks Notch signaling), latent membrane protein 1 (LMP1) (which mimics CD40 signaling), and EBV-encoded nuclear antigen 3A (EBNA3A) and EBNA3C (which inhibit oncogene-induced senescence and apoptosis). However, we recently showed that an LMP1-deleted EBV mutant induces B cell lymphomas in a newly developed cord blood-humanized mouse model that allows EBV-infected B cells to interact with CD4 T cells (the major source of CD40 ligand). Here we examined whether the EBV LMP2A protein, which mimics constitutively active B cell receptor signaling, is required for EBV-induced lymphomas in this model. We find that the deletion of LMP2A delays the onset of EBV-induced lymphomas but does not affect the tumor phenotype or the number of tumors. The simultaneous deletion of both LMP1 and LMP2A results in fewer tumors and a further delay in tumor onset. Nevertheless, the LMP1/LMP2A double mutant induces lymphomas in approximately half of the infected animals. These results indicate that neither LMP1 nor LMP2A is absolutely essential for the ability of EBV to induce B cell lymphomas in the cord blood-humanized mouse model, although the simultaneous loss of both LMP1 and LMP2A decreases the proportion of animals developing tumors and increases the time to tumor onset. Thus, the expression of either LMP1 or LMP2A may be sufficient to promote early-onset EBV-induced tumors in this model.IMPORTANCE EBV causes human lymphomas, but few models are available for dissecting how EBV causes lymphomas in vivo in the context of a host immune response. We recently used a newly developed cord blood-humanized mouse model to show that EBV can cooperate with human CD4 T cells to cause B cell lymphomas even when a major viral transforming protein, LMP1, is deleted. Here we examined whether the EBV protein LMP2A, which mimics B cell receptor signaling, is required for EBV-induced lymphomas in this model. We find that the deletion of LMP2A alone has little effect on the ability of EBV to cause lymphomas but delays tumor onset. The deletion of both LMP1 and LMP2A results in a smaller number of lymphomas in infected animals, with an even more delayed time to tumor onset. These results suggest that LMP1 and LMP2A collaborate to promote early-onset lymphomas in this model, but neither protein is absolutely essential.

Low Dietary c9t11-Conjugated Linoleic Acid Intake from Dairy Fat or Supplements Reduces Inflammation in Collagen-Induced Arthritis.

Dietary cis-9,trans-11 (c9t11) conjugated linoleic acid (CLA) fed at 0.5 % w/w was previously shown to attenuate inflammation in the murine collagen-induced (CA) arthritis model, and growing evidence implicates c9t11-CLA as a major anti-inflammatory component of dairy fat. To understand c9t11-CLA's contribution to dairy fat's anti-inflammatory action, the minimum amount of dietary c9t11-CLA needed to reduce inflammation must be determined. This study had two objectives: (1) determine the minimum dietary anti-inflammatory c9t11-CLA intake level in the CA model, and (2) compare this to anti-inflammatory effects of dairy fat (non-enriched, naturally c9t11-CLA-enriched, or c9t11-CLA-supplemented). Mice received the following dietary fat treatments (w/w) post arthritis onset: corn oil (6 % CO), 0.125, 0.25, 0.375, and 0.5 % c9t11-CLA, control butter (6 % CB), c9t11-enriched butter (6 % EB), or c9t11-CLA-supplemented butter (6 % SB, containing 0.2 % c9t11-CLA). Paw arthritic severity and pad swelling were scored and measured, respectively, over an 84-day study period. All c9t11-CLA and butter diets decreased the arthritic score (25-51 %, P < 0.01) and paw swelling (8-11 %, P < 0.01). Throughout the study, plasma tumor necrosis factor (TNFα) was elevated in CO-fed arthritic mice compared to non-arthritic (NA) mice but was reduced in 0.5 % c9t11-CLA- and EB-fed mice. Interleukin-1ß and IL-6 were increased in arthritic CO-fed mice compared to NA mice but were reduced in 0.5 % c9t11-CLA- and EB-fed mice through day 42. In conclusion, 0.125 % c9t11-CLA reduced clinical arthritis as effectively as higher doses, and decreased arthritis in CB-fed mice suggested that the minimal anti-inflammatory levels of c9t11-CLA might be below 0.125 %.

Prenatal Alcohol Exposure Alters Fetal Iron Distribution and Elevates Hepatic Hepcidin in a Rat Model of Fetal Alcohol Spectrum Disorders.

BACKGROUND: Prenatal alcohol exposure (PAE) causes neurodevelopmental disabilities, and gestational iron deficiency (ID) selectively worsens learning and neuroanatomical and growth impairments in PAE. It is unknown why ID worsens outcomes in alcohol-exposed offspring. OBJECTIVE: We hypothesized that PAE alters maternal-fetal iron distribution or its regulation. METHODS: Nulliparous, 10-wk-old, Long-Evans rats were mated and then fed iron-sufficient (100 mg Fe/kg) or iron-deficient (≤4 mg Fe/kg) diets. On gestational days 13.5-19.5, dams received either 5.0 g ethanol/kg body weight (PAE) or isocaloric maltodextrin by oral gavage. On gestational day 20.5, maternal and fetal clinical blood counts, tissue mineral and iron transport protein concentrations, and hepatic hepcidin mRNA expression were determined. RESULTS: In fetal brain and liver (P < 0.001) and in maternal liver (P < 0.005), ID decreased iron (total and nonheme) and ferritin content by nearly 200%. PAE reduced fetal bodyweight (P < 0.001) and interacted with ID (P < 0.001) to reduce it by an additional 20%. Independent of maternal iron status, PAE increased fetal liver iron (30-60%, P < 0.001) and decreased brain iron content (total and nonheme, 15-20%, P ≤ 0.050). ID-PAE brains had lower ferritin, transferrin, and transferrin receptor content (P ≤ 0.002) than ID-maltodextrin brains. PAE reduced fetal hematocrit, hemoglobin, and red blood cell numbers (P < 0.003) independently of iron status. Unexpectedly, and also independent of iron status, PAE increased maternal and fetal hepatic hepcidin mRNA expression >300% (P < 0.001). CONCLUSIONS: PAE altered fetal iron distribution independent of maternal iron status in rats. The elevated iron content of fetal liver suggests that PAE may have limited iron availability for fetal erythropoiesis and brain development. Altered fetal iron distribution may partly explain why maternal ID substantially worsens growth and behavioral outcomes in PAE.

Maternal iron deficiency worsens the associative learning deficits and hippocampal and cerebellar losses in a rat model of fetal alcohol spectrum disorders.

BACKGROUND: Gestational alcohol exposure causes lifelong physical and neurocognitive deficits collectively referred to as fetal alcohol spectrum disorders (FASDs). Micronutrient deficiencies are common in pregnancies of alcohol-abusing women. Here we show the most common micronutrient deficiency of pregnancy-iron deficiency without anemia-significantly worsens neurocognitive outcomes following perinatal alcohol exposure. METHODS: Pregnant rats were fed iron-deficient (ID) or iron-sufficient diets from gestational day 13 to postnatal day (P) 7. Pups received alcohol (0, 3.5, 5.0 g/kg) from P 4 to P 9, targeting the brain growth spurt. At P 32, learning was assessed using delay or trace eyeblink classical conditioning (ECC). Cerebellar interpositus nucleus (IPN) and hippocampal CA1 cellularity was quantified using unbiased stereology. RESULTS: Global analysis of variance revealed that ID and alcohol separately and significantly reduced ECC learning with respect to amplitude (ps ≤ 0.001) and conditioned response [CR] percentage (ps ≤ 0.001). Iron and alcohol interacted to reduce CR percentage in the trace ECC task (p = 0.013). Both ID and alcohol significantly reduced IPN (ps < 0.001) and CA1 cellularity (ps < 0.005). CR amplitude correlated with IPN cellularity (delay: r = 0.871, trace: r = 0.703, ps < 0.001) and CA1 cellularity (delay: r = 0.792, trace: r = 0.846, ps < 0.001) across both tasks. The learning impairments persisted even though the offsprings' iron status had normalized. CONCLUSIONS: Supporting our previous work, gestational ID exacerbates the associative learning deficits in this rat model of FASD. This is strongly associated with cellular reductions within the ECC neurocircuitry. Significant learning impairments in FASD could be the consequence, in part, of pregnancies in which the mother was also iron inadequate.

Dietary trans-10,cis-12 CLA reduces murine collagen-induced arthritis in a dose-dependent manner.

Dietary trans-10,cis-12 (t10c12) conjugated linoleic acid (CLA) has been shown to reduce inflammation in a murine collagen-induced arthritis (CA) model. To understand the anti-inflammatory potential of t10c12-CLA in the diet, the minimum dose of pure dietary t10c12-CLA capable of reducing CA was investigated. Because plasma inflammatory cytokines often do not reflect the progression of late-stage arthritis, inflamed tissue cytokine concentrations were also investigated in relation to increasing dietary t10c12-CLA amounts. Mice were randomly assigned to the following dietary treatments upon the establishment of arthritis: corn oil (CO) or 0.125%, 0.25%, 0.375%, or 0.5% t10c12-CLA (wt:wt) for 84 d. Sham mice (no arthritis) were fed CO and served as controls. Arthritic paw score, based on subjective assessment of arthritic severity, and paw thickness decreased linearly overall [16-65% (P < 0.001) and 0.5-12% (P < 0.001), respectively] as dietary t10c12-CLA increased (P < 0.001, R(2) < 0.81). Increasing dietary t10c12-CLA was associated with a decrease in plasma interleukin (IL)-1ß at days 21 and 42 compared with CO-fed arthritic mice, such that mice fed ≥0.25% t10c12-CLA had IL-1ß concentrations that were similar to sham mice. Plasma cytokines returned to sham mice concentrations by day 63 regardless of treatment; however, an arthritis-induced elevation in paw IL-1ß decreased linearly as dietary t10c12-CLA concentrations increased at day 84 (P = 0.007, R(2) = 0.92). Similarly, increasing dietary t10c12-CLA linearly decreased paw tumor necrosis factor (TNF)-α (P = 0.05, R(2) = 0.70). In conclusion, ≥0.125% t10c12-CLA dose-dependently reduced inflammation in a murine CA model.

Individual isomers of conjugated linoleic acid reduce inflammation associated with established collagen-induced arthritis in DBA/1 mice.

Previously, dietary conjugated linoleic acid [(CLA), an equal mixture of cis-9, trans-11 (c9t11) and trans-10, cis-12 (t10c12) CLA isomers], was found to reduce inflammation in the murine collagen antibody-induced arthritis model, but less so in the murine collagen-induced arthritis (CIA) model, an arthritic model dependent upon acquired immunity. Because CLA is known to alter the acquired immune response, it was hypothesized that feeding CLA after the establishment of arthritis would reduce paw swelling in the CIA model. In this study, upon the establishment of arthritic symptoms, mice were randomized to the following dietary treatments: corn oil (CO) control (n = 6), 0.5% c9t11-CLA (n = 8), 0.5% t10c12-CLA (n = 6), or 1% combined CLA (1:1 c9t11:t10c12-CLA, n = 6). Paws were scored for severity of arthritis and measured for changes in thickness during an 84-d study period. Dietary c9t11- and combined-CLA similarly decreased the arthritic score (29%, P = 0.036, P = 0.049, respectively, when normalized to initial score) and paw thickness (0.11 mm, P = 0.027, P = 0.035, respectively) compared with CO. Dietary t10c12-CLA reduced the arthritic score (41%, P = 0.007 when normalized) and paw thickness (0.12 mm, P = 0.013) relative to CO. Reduced interleukin-1beta on d 7 and 21 for all CLA treatments (n = 3) relative to CO suggested that antiinflammatory effects of CLA isomers might work by common mechanisms of known pathways involved in chronic inflammation. In conclusion, dietary CLA reduced inflammation associated with CIA, and both c9t11-CLA and t10c12-CLA exhibited antiinflammatory effects.

Taser blunt probe dart-to-heart distance causing ventricular fibrillation in pigs.

The maximum distance between the heart and a model Taser stimulation dart, called the dart-to-heart distance, at which the Taser can directly cause ventricular fibrillation (VF), was measured in pigs. A 9-mm-long blunt probe was advanced snugly through the surrounding tissues toward the heart. Five animals [pig mass=61.2+/-6.23 standard deviation (SD) kg] for ten dart-to-heart distances where the Taser caused VF were tested. The dart-to-heart distances where the Taser caused VF of the first stimulation site ranged from 4 to 8 mm with average 6.2 mm+/-1.79 (SD) and of the second stimulation site ranged from 2 to 8 mm with average 5.4 mm+/-2.41 (SD). The results help inform the evolving discussion of risks associated with Tasers.

A mechanistic approach to understanding conjugated linoleic acid's role in inflammation using murine models of rheumatoid arthritis.

A naturally occurring fatty acid, conjugated linoleic acid (CLA), reduces immune-induced TNF and inducible cyclooxygenase (COX-2) expression; key mediators of inflammation in rheumatoid arthritis (RA). On the basis of previous work, it was hypothesized that dietary CLA would act as an anti-inflammatory agent in select animal models of RA. In the collagen antibody-induced arthritis (CAIA) model, mice fed CLA (mixed isomers of c9, t11, and t10, c12-CLA) for 3 wk before anticollagen antibody injection had reduced lipopolysaccharide-induced plasma TNF levels and had arthritic scores that were 60% of mice fed corn oil (CO). In the collagen-induced arthritis (CIA) model, mice fed mixed isomers of CLA for 21 days before immunization had lower IgG(1) titers, earlier signs of joint inflammation, but similar arthritis scores compared with CO fed mice during the remaining 70-day post-injection period. Beginning on day 80 to 133, CLA-fed mice had arthritic scores 70% that of the CO-fed mice. In a second CIA experiment, CLA was fed only after the booster injection. Plasma IgG(1) levels were not reduced and arthritis onset was delayed 4 days in CLA-fed mice compared with the CO-fed mice. Peak arthritis score was similar between CLA and CO-fed mice from day 35 to 56. Because CLA reduced inflammation in the CAIA model, delayed onset of arthritis in the CIA model (CIA experiment 2) and reduced arthritis score after day 80 in the CIA model (CIA experiment 1), we concluded that dietary CLA exhibited anti-inflammatory activity that was dependent on antibody.