Biomedical subjects

Craig D Albright

Publications and source records attributed to Craig D Albright.

11 recordsLinked to original sources

PubMed2005

Maternal dietary choline availability alters the balance of netrin-1 and DCC neuronal migration proteins in fetal mouse brain hippocampus.

Alterations in maternal dietary choline availability during days 12-17 of pregnancy led to an increase in the level of immunoreactive netrin-1 and a decrease in the level of DCC protein in the developing fetal mouse brain hippocampus compared with controls. Changes in the expression of cell migration cues during development could account for some of the lifelong consequences of maternal dietary choline availability for cognitive and memory processes.

Animals↗

PubMed2005

Breast cancer cell-targeted oxidative stress: enhancement of cancer cell uptake of conjugated linoleic acid, activation of p53, and inhibition of proliferation.

We investigated the mechanism of inhibition of cell proliferation by mixed isomers of CLA (9-cis, 11-trans CLA; 10-trans, 12-cis CLA) on human, non-tumorigenic MCF10A cells that were derived from mammary ductal epithelial cells and MCF7 cells that were derived from a well differentiation mammary adenocarcinoma. When treated in the log phase of growth, the uptake of CLA by MCF7 exceeded the levels measured in MCF10A cells. Treatment with CLA in the presence of HPO doubled the incorporation of CLA in MCF7 cells, independent of the isomer, but reduced the incorporation of CLA by MCF10A cells. CLA caused tumor cell-targeted increased expression of 4-hydroxy-2-nonenal (4HNE), a product of lipid peroxidation, and decreased proliferation in MCF7 cells, as measured by the incorporation of bromodeoxyuridine (BrdU) and expression of phosphorylated histone H3, and the effects of CLA in combination with HPO on mitosis were greater than the effects of either agent alone. Decreased cell proliferation in CLA-treated MCF7 cells coincided with increased nuclear localization of phosphorylated, activated p53 protein, and decreased nuclear localization of the transcription factor FKHRSer256. Importantly, CLA-treated MCF7 cells were more sensitive than MCF10A cells to HPO-induced 4HNE, expression of p53, and decreased mitotic activity. These studies suggest that tumor cell-targeted increased sensitivity to oxidative stress and activation of p53 play important roles in the regulation of human breast cancer cell proliferation by CLA.

Breast Neoplasms↗

PubMed2005

Regulation of choline deficiency apoptosis by epidermal growth factor in CWSV-1 rat hepatocytes.

Previous studies show that acute choline deficiency (CD) triggers apoptosis in cultured rat hepatocytes (CWSV-1 cells). We demonstrate that prolonged EGF stimulation (10 ng/mL x 48 hrs) restores cell proliferation, as assessed by BrdU labeling, and protects cells from CD-induced apoptosis, as assessed by TUNEL labeling and cleavage of poly(ADP-ribose) polymerase. However, EGF rescue was not accompanied by restoration of depleted intracellular concentrations of choline, glycerphosphocholine, phosphocholine, or phosphatidylcholine. In contrast, we show that EGF stimulation blocks apoptosis by restoring mitochondrial membrane potential (Delta Psi(m)), as determined using the potential-sensitive dye chloromethyl-X-rosamine, and by preventing the release and nuclear localization of cytochrome c. We investigated whether EGF rescue involves EGF receptor phosphorylation and activation of the down-stream cell survival factor Akt. Compared to cells in control medium (CT, 70 micromol choline x 48 hrs), cells in CD medium (5 micromol choline) were less sensitive to EGF-induced (0-300 ng/mL x 5 min) receptor tyrosine phosphorylation. Compared to cells in CT medium, cells in CD medium treated with EGF (10 ng/mL x 5 min) exhibited higher levels of phosphatidylinositol 3-kinase (PI3K)-dependent phosphorylation of AktSer473. Inactivation of PI3K was sufficient to block EGF-stimulated activation of Akt, restoration of mitochondrial Delta Psi(m), and prevention of cytochrome c release. These studies indicate that stimulation with EGF activates a cell survival response against CD-apoptosis by restoring mitochondrial membrane potential and preventing cytochrome c release and nuclear translocation which are mediated by activation of Akt in hepatocytes.

Animals↗

PubMed2004

Cataract formation in a strain of rats selected for high oxidative stress.

The primary purpose of this study was to define the clinical and morphological features of cataractogenesis in the OXYS strain of rats that generate excess reactive oxygen species. Rats were sequentially examined from birth to the development of mature cataracts with slit lamp biomicroscopy. Morphology of selected stages of cataract development was studied using light and transmission electron microscopy (TEM), immunohistochemical localization of the lipid peroxidation product 4-hydroxynonenal (HNE) and fluorescent antibody labeling for DNA oxidation products. Lenses from age-matched normal rats were used as controls. OXYS rats developed cataracts as young as two weeks of age with progression to maturity by 1 year. Clinically, cataracts appeared initially either as nuclear or sub-capsular cortical changes and progressed to pronounced nuclear cataracts within months. TEM confirmed the light microscopic impression of region-specific alterations in both fiber cell cytoplasmic protein matrix and membrane structure. The outer adult nuclear region showed extensive cellular damage similar to osmotic cataracts, which is consistent with the postulated high uptake of glucose in the OXYS strain. The adult and outer fetal nuclear cells displayed several types of focal damage. The inner fetal and embryonic nuclear cells demonstrated textured cytoplasm, suggesting protein degradation or redistribution. Staining for HNE was increased in epithelium, cortex and nucleus compared to control lenses. Fluorescent antibody probes demonstrated increased levels of DNA oxidation products in OXYS rat lenses compared to age-matched controls. Fourier analysis of nuclear cytoplasm revealed significant components with corresponding sizes greater than 100 nm and, using a new theoretical approach, the texturing of the cytoplasm was shown to be sufficient to cause opacification of the nucleus. The OXYS rat appears to be an ideal model for oxidative stress cataractogenesis. The potential oxidative damage observed is extensive and characteristic of the developmental region. The source of oxidative damage may in part be a response to elevated levels of glucose. Because oxidative stress is thought to be a major factor in cataract formation in both diabetic and non-diabetic aging humans, this animal model may be a useful tool in assessing efficacy of antioxidant treatments that may slow or prevent cataract formation.

Aging↗

PubMed2004

Folic acid deficiency during late gestation decreases progenitor cell proliferation and increases apoptosis in fetal mouse brain.

In mice and rats, maternal dietary choline intake during late pregnancy modulates mitosis and apoptosis in progenitor cells of the fetal hippocampus and septum. Because choline and folate are interrelated metabolically, we investigated the effects of maternal dietary folate availability on progenitor cells in fetal mouse telencephalon. Timed-pregnant mice were fed a folate-supplemented (FS), control (FCT) or folate-deficient (FD) AIN-76 diet from d 11-17 of pregnancy. FD decreased the number of progenitor cells undergoing cell replication in the ventricular zones of the developing mouse brain septum (46.6% of FCT), caudate putamen (43.5%), and neocortex (54.4%) as assessed using phosphorylated histone H3 (a specific marker of mitotic phase) and confirmed by bromodeoxyuridine (BrdU) labeling of the S phase. In addition, 106.2% more apoptotic cells were found in FD than in FCT fetal septum. We observed 46.8% more calretinin-positive cells in the medial septal-diagonal band region of FD compared with pups from control dams. FS mice did not differ significantly from FCT mice in any of these measures. These results suggest that progenitor cells in fetal forebrain are sensitive to maternal dietary folate during late gestation.

Animals↗

PubMed2004

Dietary depletion of vitamin E and vitamin A inhibits mammary tumor growth and metastasis in transgenic mice.

We showed previously that dietary antioxidant depletion enhances tumor reactive oxygen species (ROS) and apoptosis, resulting in a reduction in brain tumor size in the TgT(121) transgenic mouse model, a nonmetastatic tumor model. Here, in a transgenic mouse model of mammary tumorigenesis with defined rates of tumor growth and lung-targeted metastasis, we determined the ability of dietary antioxidant depletion to inhibit tumor growth and metastasis. Compared with control mice fed a standard diet, antioxidant-depleted mice exhibited tumor-targeted generation of ROS manifested by increased levels of oxidatively modified DNA/RNA (8- hydroxy-2'-deoxyguanine, 8-hydroxyguanine) and lipid peroxidation (4-hydroxy-2-nonenal) in primary and metastatic tumor foci. In addition to increased tumor-targeted ROS, the number of apoptotic cells was increased approximately 500% (P < 0.01) and terminal dUTP nucleotide DNA end-labeling-positive cells 200% (P < 0.01) in mice fed the antioxidant-depleted diet, whereas the percentage of tumor cells undergoing mitosis was >50% lower than in controls (P < 0.01). The proportional distribution of small (<1.5 cm) and large (> or = 1.5 cm) primary mammary tumors differed. The mice fed the antioxidant-depleted diet had more small primary tumors (P <0.05) and fewer large primary tumors (P < 0.05). Importantly, they also had fewer lung metastatic tumor foci compared with mice fed the control diet (4.5 +/- 1.3 vs. 15.8 +/- 8.5 foci/lung, P < 0.01). These findings may be important in understanding the role of dietary antioxidant vitamins in tumor growth and metastasis.

Animals↗

PubMed2003

Mitochondrial and microsomal derived reactive oxygen species mediate apoptosis induced by transforming growth factor-beta1 in immortalized rat hepatocytes.

Transforming growth factor-beta1 (TGFbeta1) is a multifunctional cytokine that is over expressed during liver hepatocytes injury and regeneration. SV40-transformed CWSV-1 rat hepatocytes that are p53-defective undergo apoptosis in response to choline deficiency (CD) or TGFbeta1, which mediates CD-apoptosis. Reactive oxygen species (ROS) are essential mediators of apoptosis. We have shown that apoptosis induced by TGFbeta1 is accompanied by ROS generation and the ROS-trapping agent N-acetylcysteine (NAC) inhibits TGFbeta1-induced apoptosis. While persistent induction of ROS contributes to this form of apoptosis, the source of ROS generated downstream of TGFbeta1 is not clear. The mitochondria and the endoplasmic reticulum both harbor potent electron transfer chains that might be the source of ROS essential for completion of TGFbeta1-apoptosis. Here we show that CWSV-1 cells treated with cyclosporine A, which prevents opening of mitochondrial membrane pores required for ROS generation, inhibits TGFbeta1-induced apoptosis. A similar effect was obtained by treating these cells with rotenone, an inhibitor of complex 1 of the mitochondrial electron transfer chain. However, we demonstrate that TGFbeta1 induces cytochrome P450 1A1 and that metyrapone, a potent inhibitor of cytochrome P450 1A1, inhibits TGFbeta1-induced apoptosis. Therefore, our studies indicate that concurrent with promoting generation of ROS from mitochondria, TGFbeta1 also promotes generation of ROS from the cytochrome P450 electron transfer chain. Since inhibition of either of these two sources of ROS interferes with apoptosis, it is reasonable to conclude that the combined involvement of both pathways is essential for completion of TGFbeta1-induced apoptosis.

Animals↗

PubMed2003

Activation of a caspase-dependent oxidative damage response mediates TGFbeta1 apoptosis in rat hepatocytes.

Activation of transforming growth factor-beta type 1- (TGFbeta1) mediated signaling occurs in response to cell injury affecting stem-type cells and hepatocytes in liver. In this work we used WB stemlike liver epithelial cells and p53-defective CWSV-1 nontumorigenic rat hepatocytes to investigate the possible roles of caspases and oxidative stress in TGFbeta1 signaling. TGFbeta1 significantly increased the level of 4-hydroxy-2-nonenal (4-HNE), a stable product of lipid peroxidation. In addition, TGFbeta1-treated cells exhibited activation of caspases that accompanied by enhanced cleavage of the caspase substrate poly(ADP)-ribose polymerase (PARP) and induction of apoptosis. WB cells were twice as sensitive as sensitive as CWSV-1 cells to induction of TGFbeta1 apoptosis. TGFbeta1-apoptosis was significantly reduced when cells were treated with TGFbeta1 in the presence of inhibitors of caspase-1, -3, -8, and -9. Importantly, in addition to suppression of apoptosis, treatment of cells with the caspase-3 inhibitor Z-DEVD-FMK in the presence of TGFbeta1 suppressed the formation 4-HNE and restored mitotic activity. Together, these data suggest TGFbeta1 induces activation of a caspase signaling cascade that includes an oxidative damage response, PARP cleavage, and apoptosis that do not require intact p53 in rat hepatocytes.

Aldehydes↗

PubMed2003

Choline availability during embryonic development alters the localization of calretinin in developing and aging mouse hippocampus.

Choline availability in the diet during pregnancy alters fetal brain biochemistry with resulting behavioral changes that persist throughout the lifetime of the offspring. In the present study, the effects of dietary choline on the onset of GABAergic neuronal differentiation in developing fetal brain, as demarcated by the expression of calcium binding protein calretinin, are described. In these studies, timed-pregnant mice were fed choline supplemented, control or choline deficient AIN-76 diet from day 12-17 of pregnancy and the brains of their fetuses were studied on day 17 of gestation. In the primordial dentate gyrus, we found that pups from choline deficient-dams had more calretinin protein (330% increase), and pups from choline supplemented-dams had less calretinin protein (70% decrease), than did pups from control-dams. Importantly, decreased calretinin protein was still detectable in hippocampus in aged, 24-month-old mice, born of choline supplemented-dams and maintained since birth on a control diet. Thus, alterations in the level of calretinin protein in fetal brain hippocampus could underlie the known, life long effects of maternal dietary choline availability on brain development and behavior.

Aging↗

PubMed2003

Choline availability during embryonic development alters progenitor cell mitosis in developing mouse hippocampus.

Previously, we reported that dietary choline influences development of the hippocampus in fetal rat brain. It is important to know whether similar effects of choline occur in developing fetal mouse brain because interesting new experimental approaches are now available using several transgenic mouse models. Timed-pregnant mice were fed choline-supplemented (CS), control (CT) or choline-deficient (CD) AIN-76 diet from embryonic day 12 to 17 (E12-17). Fetuses from CD dams had diminished concentrations of phosphocholine and phosphatidylcholine in their brains compared with CT or CS fetuses (P < 0.05). When we analyzed fetal hippocampus on day E17 for cells with mitotic phase-specific expression of phosphorylated histone H3, we detected fewer labeled cells at the ventricular surface of the ventricular zone in the CD group (14.8 +/- 1.9) compared with the CT (30.7 +/- 1.9) or CS (36.6 +/- 2.6) group (P < 0.05). At the same time, we detected more apoptotic cells in E17 hippocampus using morphology in the CD group (11.8 +/- 1.4) than in CT (5.6 +/- 0.6) or CS (4.2 +/- 0.7) group (P < 0.05). This was confirmed using terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-digoxigenin anti-digoxigenin fluorescein conjugate antibody nick end-labeling (TUNEL) and activated caspase-3 immunoreactivity. We conclude that the dietary availability of choline to the mouse dam influences progenitor cell proliferation and apoptosis in the fetal brain.

Animals↗

PubMed2002

Differential effects of TPA and retinoic acid on cell-cell communication in human bronchial epithelial cells.

Understanding how normal and immortalized bronchial epithelial cells respond to modulators of gap junctional communication will increase our understanding of the process of tumor promotion. In the present study we compared to effects of retinoic acid (RA) and 12-O-tetradecanoylphorbol-13-acetate (TPA) on the rate of fluorescent dye transfer via gap junctions in primary human tracheo-bronchial epithelial cells (TBE) and SV40 large T-antigen immortalized, non-tumorigenic bronchial epithelial cells (BEAS-2B). RA in the physiological range (0.001-1 microM) inhibited cell proliferation (DNA synthesis, mitotic index) more in primary TBE cells than BEAS-2B cells. Also in RA-treated cells, decreased cell proliferation was coupled to decreased gap junctional communication (GJC) in TBE but not in BEAS-2B cells. TPA strongly suppressed GJC and proliferation in primary TBE cells, whereas BEAS-2B exhibited increased GJC and retained a significant fraction of cells undergoing DNA synthesis. Our studies show that an uncoupling of GJC and cell proliferation is associated with a differential response to the growth inhibitory effects of RA and phorbol esters in immortalized compared to primary human bronchial epithelial cells.

Antineoplastic Agents↗