Tocopherols are the major source of dietary vitamin E. In this study, the growth inhibitory effects of different forms of tocopherols, tocopheryl phosphates (TP) and tocopherol quinones (TQ) on human colon cancer HCT116 and HT29 cells were investigated. δ-T was more active than γ-T in inhibiting colon cancer cell growth, decreasing cancer cell colony formation and inducing apoptosis; however α-T was rather ineffective. Similarly, the rate of cellular uptake also followed the ranking order δ-T > γ-T ≫ α-T. TP and TQ generally had higher inhibitory activities than their parent compounds. Interestingly, the γ-forms of TP and TQ were more active than the δ-forms in inhibiting cancer cell growth; whereas the α-forms were the least effective. The potencies of γ-TQ and δ-TQ (showing IC50 of ~0.8 and ~2 μM on HCT116 cells after a 72-h incubation, respectively) were >100 and >20 fold higher, respectively, than those of their parent tocopherols. Induction of cancer cell apoptosis by δ-T, γ-TP and γ-TQ was characterized by the cleavage of caspase 3 and PARP1 and DNA fragmentation. These studies demonstrated the higher growth inhibitory activity of δ-T than γ-T, the even higher activities of the γ-forms of TP and TQ, and the ineffectiveness of the α-forms of tocopherol and their metabolites against colon cancer cells.
tocopherol; tocopheryl phosphate; tocopherol quinone; uptake; apoptosis
Purpose: Indol-2,3-dione (ISA), a natural substance with clear structure, has been shown to process anti-inflammatory, antioxidant and anti-atherosclerosis activity in vivo. The purpose of this study was to investigate the effect and mechanism of ISA on AS by primary rat cardiac microvascular endothelial cells (rCMEC). Methods: rCMEC cells were primary cultured, appraised by cell morphology and immune cell chemical dyeing, and passaged to the 3rd generation. The effect of ISA on the activity of rCMEC induced by oxidized low-density lipoprotein (ox-LDL) was detected by MTT method. Then we studied the effect of ISA on the adhesion of monocyte with rCMEC induced by ox-LDL. The secretion of interleutin-6 (IL-6) and tumor necrosis factor-α (TNF-α) by rCMEC were measured by enzyme-linked immunosorbent assay (ELISA) method. Finally the mRNA level of IL-6 and TNF-α of rCMEC were analyzed by real time RT-PCR. Results MTT result indicated that ISA (10-8-10-6 g/L) could inhibit rCMEC injury induced by ox-LDL in a dose-dependent manner (P < 0.05). The adhesion of monocyte with rCMEC induced by ox-LDL was inhibited by ISA in a dose-dependent manner (P < 0.05). The levels of IL-6 and TNF-α of ISA groups were significantly decreased in a dose-dependent manner compared with model group (P < 0.05). The mRNA expressions of IL-6 and TNF-α of ISA groups were also downregulated significantly compared with model group (P < 0.05). Conclusions ISA can prevent atherosclerotic lesion. Its mechanism may be that it can defend against the oxidation damage to rCMEC, inhibit the adhesion of monocyte to rCMEC, and reduce inflammatory secretions of IL-6 and TNF-α.
Indol-2; 3-dione; atherosclerosis; ox-LDL; IL-6; TNF-α
Tocopherols (vitamin E) and tea polyphenols have been reported to have cancer preventive activities. Large-scale human trials with high doses of alpha-tocopherol, however, have produced disappointing results. This review presents data showing that γ- and δ-tocopherols inhibit colon, lung, mammary and prostate carcinogenesis in animal models, whereas α-tocopherol is ineffective in animal and human studies. Possible mechanisms of action are discussed. A broad cancer preventive activity of green tea polyphenols has been demonstrated in animal models, and many mechanisms have been proposed. The cancer preventive activity of green tea in humans, however, has not been conclusively demonstrated and remains to be further investigated.
tocopherols; vitamin E; green tea; polyphenols; cancer prevention
To determine whether knockdown of Müller cell–derived VEGFA-splice variant, VEGF164, which is upregulated in the rat retinopathy of prematurity (ROP) model, safely inhibits intravitreal neovascularization (IVNV).
Short hairpin RNAs for VEGF164 (VEGF164.shRNAs) or luciferase.shRNA control were cloned into lentivectors with CD44 promoters that specifically target Müller cells. Knockdown efficiency, off-target effects, and specificity were tested in HEK reporter cell lines that expressed green fluorescent protein (GFP)-tagged VEGF164 or VEGF120 with flow cytometry or in rat Müller cells (rMC-1) by real-time PCR. In the rat oxygen-induced retinopathy (OIR) ROP model, pups received 1 μL subretinal lentivector-driven luciferase.shRNA, VEGFA.shRNA, or VEGF164.shRNA at postnatal day 8 (P8). Analyses at P18 and P25 included: IVNV and avascular retina (AVA); retinal and serum VEGF (ELISA); density of phosphorylated VEGFR2 (p-VEGFR2) in lectin-labeled retinal endothelial cells (ECs; immunohistochemistry); TUNEL staining and thickness of inner nuclear (INL) and outer nuclear layers (ONL) in retinal cryosections; and pup weight gain.
In HEK reporter and in rMC-1 cells and in comparison to lucifferase.shRNA, VEGFA.shRNA reduced both VEGF120 and VEGF164, but VEGF164.shRNA only reduced VEGF164 and not VEGF120. Compared with luciferase.shRNA, VEGFA.shRNA and VEGF164.shRNA reduced retinal VEGF and IVNV without affecting AVA at P18 and P25. At P25, VEGF164.shRNA more effectively maintained IVNV inhibition than VEGFA.shRNA. VEGFA.shRNA and VEGF164.shRNA reduced pVEGFR2 in retinal ECs at P18, but VEGFA.shRNA increased it at P25. VEGFA.shRNA increased TUNEL+ cells at P18 and decreased ONL thickness at P18 and P25. VEGFA.shRNA and VEGF164.shRNA did not affect pup weight gain and serum VEGF.
Short hairpin RNA to Müller cell VEGF164 maintained long-term inhibition of IVNV and limited cell death compared with shRNA to VEGFA.
Using a relevant model of current ROP, the rat 50/10 oxygen-induced retinopathy model, we determined that targeting Müller cell VEGF164 by lentivector-delivered shRNA achieved better inhibition of intravitreal neovascularization without causing retinal cell death compared to shRNA to VEGFA.
vascular endothelial growth factor; lentivector; short hairpin RNA; intravitreal neovascularization; Müller cells
Targeted inhibition of Müller cell (MC)–produced VEGF or broad inhibition of VEGF with an intravitreal anti-VEGF antibody reduces intravitreal neovascularization in a rat model of retinopathy of prematurity (ROP). In this study, we compared the effects of these two approaches on retinal vascular development and capillary density in the inner and deep plexi in the rat ROP model.
In the rat model of ROP, pups received 1 μL of (1) subretinal lentivector-driven short hairpin RNA (shRNA) to knockdown MC-VEGFA (VEGFA.shRNA) or control luciferase shRNA, or (2) intravitreal anti-VEGF antibody (anti-VEGF) or control isotype goat immunoglobulin G (IgG). Analyses of lectin-stained flat mounts at postnatal day 18 (p18) included: vascular/total retinal areas (retinal vascular coverage) and pixels of fluorescence/total retinal area (capillary density) of the inner and deep plexi determined with the Syncroscan microscope, and angles between cleavage planes of mitotic vascular figures labeled with anti-phosphohistone H3 and vessel length.
Retinal vascular coverage and density increased in both plexi between p8 and p18 in room air (RA) pups. Compared with RA, p18 ROP pups had reduced vascular coverage and density of both plexi. Compared with respective controls, VEGFA.shRNA treatment significantly increased vascular density in the deep plexus, whereas anti-VEGF reduced vascular density in the inner and deep plexi. Vascular endothelial growth factor-A.shRNA caused more cleavage angles predicting vessel elongation and fewer mitotic figures, whereas anti-VEGF treatment led to patterns of pathologic angiogenesis.
Targeted treatment with lentivector-driven VEGFA.shRNA permitted physiologic vascularization of the vascular plexi and restored normal orientation of dividing vascular cells, suggesting that regulation of VEGF signaling by targeted treatment may be beneficial.
Targeted inhibition of Müller cell (MC)-produced VEGF or broad inhibition of VEGF with anti-VEGF antibody reduces intravitreal neovascularization (IVNV) in the rat retinopathy of prematurity (ROP) model. We compared the effects of these two approaches on retinal vascular area and capillary density of the inner and deep plexi.
VEGF; vascular extent; vascular density; intrvitreal neovscularization; rat model of retinopathy of prematurity
Recent advances in time-lapse monitoring in IVF treatment have provided new morphokinetic markers for embryonic competence. However, there is still very limited information about the relationship between morphokinetic parameters, chromosomal compositions and implantation potential. Accordingly, this study aimed at investigating the effects of selecting competent blastocysts for transfer by combining time-lapse monitoring and array CGH testing on pregnancy and implantation outcomes for patients undergoing preimplantation genetic screening (PGS).
A total of 1163 metaphase II (MII) oocytes were retrieved from 138 PGS patients at a mean age of 36.6 ± 2.4 years. These sibling MII oocytes were then randomized into two groups after ICSI: 1) Group A, oocytes (n = 582) were cultured in the time-lapse system and 2) Group B, oocytes (n = 581) were cultured in the conventional incubator. For both groups, whole genomic amplification and array CGH testing were performed after trophectoderm biopsy on day 5. One to two euploid blastocysts within the most predictive morphokinetic parameters (Group A) or with the best morphological grade available (Group B) were selected for transfer to individual patients on day 6. Ongoing pregnancy and implantation rates were compared between the two groups.
There were significant differences in clinical pregnancy rates between Group A and Group B (71.1% vs. 45.9%, respectively, p = 0.037). The observed implantation rate per embryo transfer significantly increased in Group A compared to Group B (66.2% vs. 42.4%, respectively, p = 0.011). Moreover, a significant increase in ongoing pregnancy rates was also observed in Group A compared to Group B (68.9% vs. 40.5%. respectively, p = 0.019). However, there was no significant difference in miscarriage rate between the time-lapse system and the conventional incubator (3.1% vs. 11.8%, respectively, p = 0.273).
This is the first prospective investigation using sibling oocytes to evaluate the efficiency of selecting competent blastocysts for transfer by combining time-lapse monitoring and array CGH testing for PGS patients. Our data clearly demonstrate that the combination of these two advanced technologies to select competent blastocysts for transfer results in improved implantation and ongoing pregnancy rates for PGS patients.
Time-lapse monitoring; Array CGH; PGS; Ploidy; Implantation; Miscarriage
L-arginine supplementation is proposed to improve health status or as adjunct therapy for diseases including cardiovascular diseases. However, controversial results and even detrimental effects of L-arginine supplementation are reported. We investigate potential mechanisms of L-arginine-induced detrimental effects on vascular endothelial cells. Human endothelial cells were exposed to a physiological (0.1 mmol/L) or pharmacological (0.5 mmol/L) concentration of L-arginine for 30 minutes (acute) or 7 days (chronic). The effects of L-arginine supplementation on endothelial senescence phenotype, i.e., levels of senescence-associated beta-galactosidase, expression of vascular cell adhesion molecule-1 and intercellular adhesion molecule-1, eNOS-uncoupling, arginase-II expression/activity, and mTORC1-S6K1 activity were analyzed. While acute L-arginine treatment enhances endothelial NO production accompanied with superoxide production and activation of S6K1 but no up-regulation of arginase-II, chronic L-arginine supplementation causes endothelial senescence, up-regulation of the adhesion molecule expression, and eNOS-uncoupling (decreased NO and enhanced superoxide production), which are associated with S6K1 activation and up-regulation of arginase-II. Silencing either S6K1 or arginase-II inhibits up-regulation/activation of each other, prevents endothelial dysfunction, adhesion molecule expression, and senescence under the chronic L-arginine supplementation condition. These results demonstrate that S6K1 and arginase-II form a positive circuit mediating the detrimental effects of chronic L-arginine supplementation on endothelial cells.
Arginase-II; endothelium; L-arginine; Senescence; mTOR; adhesion molecules
NADPH oxidase–generated reactive oxygen species (ROS) are implicated in angiogenesis. Isoforms of NADPH oxidase NOX1, NOX2, and NOX4 are reported to be expressed in endothelial cells (ECs). Of these, NOX1 and NOX2 have been reported to contribute to intravitreal neovascularization (IVNV) in oxygen-induced retinopathy (OIR) models. In this study, we tested the hypothesis that the isoform NOX4 in ECs contributed to vascular endothelial growth factor (VEGF)–induced angiogenesis and IVNV.
Isoforms of NADPH oxidase mRNA were measured in several types of cultured vascular ECs: human retinal microvascular ECs (hRMVECs), choroidal ECs (CECs), and human umbilical vascular ECs (HUVECs) using real-time PCR. Newborn rat pups and dams were placed into an OIR model that cycled oxygen concentration between 50% and 10% every 24 h for 14 days, and then were placed in room air (RA) for an additional 4 days (rat OIR model). NOX4 expression in retinal lysates from the RA–raised pups at postnatal day 0 (P0), P14, and P18 was determined with western blots. STAT3 activation was determined as the ratio of phosphorylated STAT3 to total STAT3 with western blot analysis of retinal lysates from pups raised in RA or from the rat OIR model at P18. Semiquantitative assessment of the density of NOX4 colabeling with lectin-stained retinal ECs was determined by immunolabeling of retinal cryosections from P18 pups in OIR or in RA. In hRMVECs transfected with NOX4 siRNA and treated with VEGF or control, 1) ROS generation was measured using the 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate, acetyl ester fluorescence assay and 2) phosphorylated VEGF receptor 2 and STAT3, and total VEGFR2 and STAT3 were measured in western blot analyses. VEGF-stimulated hRMVEC proliferation was measured following transfection with NOX4 siRNA or STAT3 siRNA, or respective controls.
NOX4 was the most prevalent isoform of NADPH oxidase in vascular ECs. NOX4 expression in retinal lysates was significantly decreased during development in RA. Compared to RA, the expression of retinal NOX4 increased at P18. At p18 OIR, semiquantitative assessment of the density of lectin and NOX4 colabeling in retinal vascular ECs was greater in retinal cryosections and activated STAT3 was greater in retinal lysates when compared to the RA-raised pups. In cultured hRMVECs, knockdown of NOX4 by siRNA transfection inhibited VEGF-induced ROS generation. VEGF induced a physical interaction of phosphorylated-VEGFR2 and NOX4. Knockdown of NOX4: 1) reduced VEGFR2 activation but did not abolish it and 2) abolished STAT3 activation in response to VEGF. Knockdown of either NOX4 or STAT3 inhibited VEGF-induced EC proliferation.
Our data suggest that in a model representative of human retinopathy of prematurity, NOX4 was increased at a time point when IVNV developed. VEGF-activated NOX4 led to an interaction between VEGF-activated VEGFR2 and NOX4 that mediated EC proliferation via activation of STAT3. Altogether, our results suggest that NOX4 may regulate VEGFR2-mediated IVNV through activated STAT3.
Macrophages play a paramount role in immunity and inflammation-associated diseases, including infections, cardiovascular diseases, obesity-associated metabolic imbalances, and cancer. Compelling evidence from studies of recent years demonstrates that macrophages are heterogeneous and undergo heterogeneous phenotypic changes in response to microenvironmental stimuli. The M1 killer type response and the M2 repair type response are best known, and are two extreme examples. Among other markers, inducible nitric oxide synthase and type-I arginase (Arg-I), the enzymes that are involved in l-arginine/nitric oxide (NO) metabolism, are associated with the M1 and M2 phenotype, respectively, and therefore widely used as the markers for characterization of the two macrophage phenotypes. There is also a type-II arginase (Arg-II), which is expressed in macrophages and prevalently viewed as having the same function as Arg-I in the cells. In contrast to Arg-I, little information on the role of Arg-II in macrophage inflammatory responses is available. Emerging evidence, however, suggests that differential roles of Arg-I and Arg-II in regulating macrophage functions. In this article, we will review recent developments on the functional roles of the two arginase isoforms in regulation of macrophage inflammatory responses by focusing on their impact on the pathogenesis of cardiovascular diseases and metabolic disorders.
arginase; arginine; macrophages; nitric oxide synthase; cardiovascular diseases
In assisted reproductive treatments, embryos remaining after fresh embryo transfer are usually selected for cryopreservation based on traditional morphology assessment. Our previous report has demonstrated that array comparative genomic hybridization (aCGH) screening for IVF patients with good prognosis significantly improves clinical and ongoing pregnancy rates in fresh embryo transfer cycles. The current study further investigates the efficiency of applying aCGH in the selection of euploid embryos for cryopreservation as related to pregnancy and implantation outcomes in subsequent frozen embryo transfer (FET) cycles.
First-time IVF patients with good prognosis undergoing fresh single embryo transfer and having at least one remaining blastocyst for cryopreservation were prospectively randomized into two groups: 1) Group A patients had embryos assessed by morphology first and then by aCGH screening of trophectoderm cells and 2) Group B patients had embryos evaluated by morphology alone. All patients had at least one blastocyst available for cryopreservation after fresh embryo transfer. There were 15 patients in Group A and 23 patients in Group B who failed to conceive after fresh embryo transfer and completed the FET cycles. Blastocyst survival and implantation rates were compared between the two groups.
There were no significant differences in blastocyst survival rates between Group A and Group B (90.9% vs. 91.3%, respectively; p >0.05). However, a significantly higher implantation rate was observed in the morphology assessment plus aCGH screening group compared to the morphology assessment alone group (65.0% vs. 33.3%, respectively; p = 0.038). There was no miscarriage observed in Group A while a 16.7% miscarriage rate was recorded in Group B (0% vs. 16.7%, respectively; p >0.05).
While aCGH screening has been recently applied to select euploid blastocysts for fresh transfer in young, low-risk IVF patients, this is the first prospective study on the impact of aCGH specifically on blastocyst survival and implantation outcomes in the subsequent FET cycles of IVF patients with good prognosis. The present study demonstrates that aCGH screening of blastocysts prior to cryopreservation significantly improves implantation rates and may reduce the risk of miscarriage in subsequent FET cycles. Further randomized clinical studies with a larger sample size are needed to validate these preliminary findings.
aCGH; Trophectoderm biopsy; Cryopreservation; Implantation
Vascular smooth muscle cell (VSMC) senescence and apoptosis are involved in atherosclerotic plaque vulnerability. Arginase‐II (Arg‐II) has been shown to promote vascular dysfunction and plaque vulnerability phenotypes in mice through uncoupling of endothelial nitric oxide synthase and activation of macrophage inflammation. The function of Arg‐II in VSMCs with respect to plaque vulnerability is unknown. This study investigated the functions of Arg‐II in VSMCs linking to plaque vulnerability.
Methods and Results
In vitro studies were performed on VSMCs isolated from human umbilical veins, whereas in vivo studies were performed on atherosclerosis‐prone apolipoprotein E‐deficient (ApoE−/−) mice. In nonsenescent VSMCs, overexpressing wild‐type Arg‐II or an l‐arginine ureahydrolase inactive Arg‐II mutant (H160F) caused similar effects on mitochondrial dysfunction, cell apoptosis, and senescence, which were abrogated by silencing p66Shc or p53. The activation of p66Shc but not p53 by Arg‐II was dependent on extracellular signal‐regulated kinases (ERKs) and sequential activation of 40S ribosomal protein S6 kinase 1 (S6K1)—c‐Jun N‐terminal kinases (JNKs). In senescent VSMCs, Arg‐II and S6K1, ERK‐p66Shc, and p53 signaling levels were increased. Silencing Arg‐II reduced all these signalings and cell senescence/apoptosis. Conversely, silencing p66Shc reduced ERK and S6K1 signaling and Arg‐II levels and cell senescence/apoptosis. Furthermore, genetic ablation of Arg‐II in ApoE−/− mice reduced the aforementioned signaling and apoptotic VSMCs in the plaque of aortic roots.
Arg‐II, independently of its l‐arginine ureahydrolase activity, promotes mitochondrial dysfunction leading to VSMC senescence/apoptosis through complex positive crosstalk among S6K1‐JNK, ERK, p66Shc, and p53, contributing to atherosclerotic vulnerability phenotypes in mice.
apoptosis; arginase; p53; p66Shc; vascular smooth muscle cells
Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and is increasing in frequency in the U.S. The major reason for the low postoperative survival rate of HCC is widespread intrahepatic metastasis or invasion, and activation of TGFβ signaling is associated with the invasive phenotype. This study aims at determining the novel function of miR-127 in modulating HCC migration. Overexpression of miR-127 inhibits HCC cell migration, invasion and tumor growth in nude mice. MiR-127 directly represses matrix metalloproteinase 13 (MMP13) 3′UTR activity and protein expression, and diminishes MMP13/TGFβ-induced HCC migration. In turn, TGFβ decreases miR-127 expression by enhancing c-Jun-mediated inhibition of miR-127 promoter activity. In contrast, p53 transactivates miR-127 promoter and induces miR-127 expression, which is antagonized by c-Jun. The inhibition of miR-127 by c-Jun is through TGFβ-mediated ERK and JNK pathways. The lower miR-127 expression shows a negative correlation with the higher MMP13 expression in a subset of human HCC specimens. This is the first report elucidating a feedback regulation between miR-127 and the TGFβ/c-Jun cascade in HCC migration via MMP13 that involves a crosstalk between the oncogene c-Jun and tumor suppressor p53.
Background and Purpose
Cerebral blood oxygenation level is critical for following the evolution of stroke patients. The purpose of this study was to investigate the feasibility of measuring changes in blood oxygen levels for patients with acute stroke using SWI and to compare these changes with the patient's recovery over time.
Materials and Methods
A total 30 MRI scans was performed on 10 acute ischemic stroke patients. Every patient was followed at three time points: less than 24 hours; 2–3 weeks after stroke and 2 months after stroke. Both MRI scan and NIH stroke scale (NIHSS) were acquired for each patient at all three time points. Oxygen saturation changes were derived from phase values differences (Δφ) measured over 10 veins from each hemisphere for all 10 patients over 3 time points. The correlation of oxygen saturation and NIHSS was further evaluated.
The stroke affected side of the brain showed moderate (r = −0.62) to strong (r = −0.70) correlation between the oxygenation change and NIHSS change. The oxygen saturation change from the normal side of the brain had essentially no association with recovery (r = −0.02 and−0.31). The results suggest that increases in oxygen saturation correspond to improved outcome and reductions in oxygen saturation correspond to worse outcome.
High resolution SWI provided a novel method to measure changes in oxygenation change of the human brain in vivo. By using the phase values from the veins, both spatial and temporal information can be found that relates to patient outcome post stroke.
Mdm2 is a crucial negative regulator of the tumor suppressor function of p53. However, little is known about Mdm2 protein stability regulation by other tumor suppressors. Nuclear receptor small heterodimer partner (SHP, NROB2) functions as a tumor suppressor in liver cancer. We show here a surprising finding of a feedback regulatory loop between SHP and Mdm2. SHP stabilizes Mdm2 protein by abrogating Mdm2 self-ubiquitination, and Mdm2 in turn attenuates SHP protein levels under p53-deficient conditions. Such cross-regulation critically depends on the physical interaction of SHP with Mdm2 through the SHP K170 residue. The Mdm2-SHP interplay represents a novel component of Mdm2 signaling that is likely to dictate Mdm2 activity and function.
nuclear receptor; small heterodimer partner; protein stability; Mdm2
The cancer preventive activity of vitamin E has been extensively discussed, but the activities of specific forms of tocopherols have not received sufficient attention. Herein, we compared the activities of δ-tocopherol (δ-T), γ-T and α-T in a colon carcinogenesis model. Male F344 rats, 7 weeks old, were given 2 weekly subcutaneous injections of azoxymethane (AOM) each at a dose of 15 mg/kg body weight. Starting 1 week before the AOM injection, the animals were maintained on a modified AIN76A diet, or the same diet containing 0.2% of δ-T, γ-T, α-T or a γ-T-rich mixture of tocopherols (γ-TmT), until the termination of the experiment at 8 weeks after the second AOM injection. δ-T treatment showed the strongest inhibitory effect, decreasing the numbers of aberrant crypt foci by 62%. γ-T and γ-TmT were also effective, but α-T was not. Immunohistochemical analysis showed that δ-T and γ-T treatments reduced the levels of 4-hydroxynonenal and nitrotyrosine and the expression of cyclin D1 in the colon, preserved the expression of PPAR-γ, and decreased the serum levels of prostaglandin E2 and 8-isoprostane. Supplementation with 0.2% δ-T, γ-T or α-T increased the respective levels of tocopherols and their side-chain degradation metabolites in the serum and colon tissues. Rather high concentrations of δ-T and γ-T and their metabolites were found in colon tissues. Our study provides the first evidence for the much higher cancer preventive activity of δ-T and γ-T than α-T in a chemically-induced colon carcinogenesis model. It further suggests that δ-T is more effective than γ-T.
Tocopherols; tocopherol metabolites; colon carcinogenesis; ACF
GMRP1, also known as BTBD10, has been reported to inhibit apoptosis of neuronal and islet beta cells via Akt pathway. The present study attempted to investigate whether GMRP1 and its mediated Akt pathway were involved in brain injury of rats after intracerebral hemorrhage (ICH). Rat models of ICH had been established successfully. Western blotting was used to investigate the levels of GMRP1 protein in caudate nuclei tissues of hemorrhagic and contralateral sides at 6 h, day 1, day 3, day 5, day 7 after ICH. Phosphorylation of Akt was determined in caudate nuclei mentioned above. TUNEL assay was used to measure the cell apoptosis. GMRP1 protein levels, as well as phosphorylations of Akt, significantly decreased in caudate nuclei of hemorrhagic side, compared with those of contralateral side at day 1, day 3 after ICH. Enhanced cell apoptosis was observed in hemorrhagic side by TUNEL assay. We presented here evidence that decreased GMRP1-mediated Akt pathway contributed to cell apoptosis in hemorrhagic side, suggesting that GMRP1 played an important role in brain damage after ICH.
GMRP1; intracerebral hemorrhage; apoptosis; Akt
We examined the effect of Mdm2 on regulation of the ApoCIII promoter and its cross-talk with p53 and nuclear receptor SHP. Overexpression of Mdm2 markedly enhanced ApoCIII promoter activity by HNF4α. A direct association of Mdm2 protein with the HNF4α protein was observed by co-immunoprecipitation. Ectopic expression of p53 decreased HNF4α activation of the ApoCIII promoter and antagonized the effect of Mdm2. Co-expression of SHP further strengthened p53 inhibition and abolished Mdm2 activation of the ApoCIII promoter. Mdm2 inhibited p53-mediated enrichment of HNF4α to the ApoCIII promoter while simultaneously reducing p53 binding and increasing recruitment of SHP to the ApoCIII promoter. The results from this study implicate a potentially important function of Mdm2 in regulation of lipoprotein metabolism.
nuclear receptor; promoter activity; tumor suppressor; oncogene; lipoprotein
Oxidative stress and inflammation in the vascular wall are essential mechanisms of atherosclerosis and vascular dysfunctions associated with risk factors such as metabolic diseases, aging, hypertension, etc. Evidence has been provided that activation of the vascular endothelial cells in the presence of the risk factors promotes oxidative stress and vascular inflammatory responses, leading to acceleration of atherosclerotic vascular disease. Increasing number of studies from recent years demonstrates that uncoupling of endothelial nitric oxide synthase (eNOS), whereby the enzyme eNOS produces detrimental amount of superoxide anion O2− instead the vasoprotective nitric oxide (NO⋅), plays a critical role in vascular dysfunction under various pathophysiological conditions and in aging. The mechanisms of eNOS-uncoupling seem multiple and complex. Recent research provides emerging evidence supporting an essential role of increased activity of arginases including arginase-I and arginase-II in causing eNOS-uncoupling, which results in vascular oxidative stress and inflammatory responses, and ultimately leading to vascular diseases. This review article will summarize the most recent findings on the functional roles of arginases in vascular diseases and/or dysfunctions and the underlying mechanisms in relation to oxidative stress and inflammations. Moreover, regulatory mechanisms of arginases in the vasculature are reviewed and the future perspectives of targeting arginases as therapeutic options in vascular diseases are discussed.
arginase; eNOS; superoxide; adhesion molecules; signal transduction pathway
We investigated regulation of miR-200c expression by nuclear receptors. Ectopic expression of miR-200c inhibited MHCC97H cell migration, which was abrogated by the synergistic effects of PPARα and LRH-1 siRNAs. The expression of miR-200c was decreased by PPARα/LRH-1 siRNAs and increased by SHP siRNAs, and overexpression of the receptors reversed the effects of their respective siRNAs. SHP siRNAs also drastically enhanced the ability of the LRH-1 agonist RJW100 to induce miR-200c and downregulate ZEB1 and ZEB2 proteins. Co-expression of PPARα and LRH-1 moderately transactivated the miR-200c promoter, which was repressed by SHP co-expression. RJW100 caused strong activation of the miR-200c promoter. This is the first report to demonstrate that miR-200c expression is controlled by nuclear receptors.
nuclear receptor; microRNA; transcription; cell migration
Previous studies have shown that high glucose increases reactive oxygen species (ROS) in endothelial cells that contributes to vascular dysfunction and atherosclerosis. Accumulation of ROS is due to dysregulated redox balance between ROS-producing systems and antioxidant systems. Previous research from our laboratory has shown that high glucose decreases the principal cellular reductant, NADPH by impairing the activity of glucose 6-phosphate dehydrogenase (G6PD). We and others also have shown that the high glucose-induced decrease in G6PD activity is mediated, at least in part, by cAMP-dependent protein kinase A (PKA). As both the major antioxidant enzymes and NADPH oxidase, a major source of ROS, use NADPH as substrate, we explored whether G6PD activity was a critical mediator of redox balance. We found that overexpression of G6PD by pAD-G6PD infection restored redox balance. Moreover inhibition of PKA decreased ROS accumulation and increased redox enzymes, while not altering the protein expression level of redox enzymes. Interestingly, high glucose stimulated an increase in NADPH oxidase (NOX) and colocalization of G6PD with NOX, which was inhibited by the PKA inhibitor. Lastly, inhibition of PKA ameliorated high glucose mediated increase in cell death and inhibition of cell growth. These studies illustrate that increasing G6PD activity restores redox balance in endothelial cells exposed to high glucose, which is a potentially important therapeutic target to protect ECs from the deleterious effects of high glucose.
Period2 (Per2) is an important component of the circadian clock. Mutation of this gene is associated with vascular endothelial dysfunction and altered glucose metabolism. The aim of this study is to further characterize whole body glucose homeostasis and endothelial nitric oxide (NO) production in response to insulin in the mPer2Brdm1 mice. We show that mPer2Brdm1 mice exhibit compromised insulin receptor activation and Akt signaling in various tissues including liver, fat, heart, and aortas with a tissue-specific heterogeneous diurnal pattern, and decreased insulin-stimulated NO release in the aortas in both active and inactive phases of the animals. As compared to wild type (WT) mice, the mPer2Brdm1 mice reveal hyperinsulinemia, hypoglycemia with lower fasting hepatic glycogen content and glycogen synthase level, no difference in glucose tolerance and insulin tolerance. The mPer2Brdm1 mice do not show increased predisposition to obesity either on normal chow or high fat diet compared to WT controls. Thus, mice with Per2 gene mutation show altered glucose homeostasis and compromised insulin-stimulated NO release, independently of obesity.
blood vessel; circadian gene; glucose; glycogen; insulin; nitric oxide; obesity; signaling
Macrophage‐mediated chronic inflammation is mechanistically linked to insulin resistance and atherosclerosis. Although arginase I is considered antiinflammatory, the role of arginase II (Arg‐II) in macrophage function remains elusive. This study characterizes the role of Arg‐II in macrophage inflammatory responses and its impact on obesity‐linked type II diabetes mellitus and atherosclerosis.
Methods and Results
In human monocytes, silencing Arg‐II decreases the monocytes’ adhesion to endothelial cells and their production of proinflammatory mediators stimulated by oxidized low‐density lipoprotein or lipopolysaccharides, as evaluated by real‐time quantitative reverse transcription‐polymerase chain reaction and enzyme‐linked immunosorbent assay. Macrophages differentiated from bone marrow cells of Arg‐II–deficient (Arg‐II−/−) mice express lower levels of lipopolysaccharide‐induced proinflammatory mediators than do macrophages of wild‐type mice. Importantly, reintroducing Arg‐II cDNA into Arg‐II−/− macrophages restores the inflammatory responses, with concomitant enhancement of mitochondrial reactive oxygen species. Scavenging of reactive oxygen species by N‐acetylcysteine prevents the Arg‐II–mediated inflammatory responses. Moreover, high‐fat diet–induced infiltration of macrophages in various organs and expression of proinflammatory cytokines in adipose tissue are blunted in Arg‐II−/− mice. Accordingly, Arg‐II−/− mice reveal lower fasting blood glucose and improved glucose tolerance and insulin sensitivity. Furthermore, apolipoprotein E (ApoE)–deficient mice with Arg‐II deficiency (ApoE−/−Arg‐II−/−) display reduced lesion size with characteristics of stable plaques, such as decreased macrophage inflammation and necrotic core. In vivo adoptive transfer experiments reveal that fewer donor ApoE−/−Arg‐II−/− than ApoE−/−Arg‐II+/+ monocytes infiltrate into the plaque of ApoE−/−Arg‐II+/+ mice. Conversely, recipient ApoE−/−Arg‐II−/− mice accumulate fewer donor monocytes than do recipient ApoE−/−Arg‐II+/+ animals.
Arg‐II promotes macrophage proinflammatory responses through mitochondrial reactive oxygen species, contributing to insulin resistance and atherogenesis. Targeting Arg‐II represents a potential therapeutic strategy in type II diabetes mellitus and atherosclerosis. (J Am Heart Assoc. 2012;1:e000992 doi: 10.1161/JAHA.112.000992.)
atherosclerosis; diabetes mellitus, type 2; inflammation; macrophages
We report here a novel interplay between tumor suppressor p53 and nuclear receptor SHP that controls p53 and SHP stability. Overexpression of p53 causes rapid SHP protein degradation, which does not require the presence of Mdm2 and is mediated by the proteosome pathway. Overexpressing SHP alone does not affect p53 stability. However, SHP destabilizes p53 by augmentation of Mdm2 ubiquitin ligase activity toward p53. The single amino acid substitution in the SHP protein SHPK170R increases SHP binding to p53 relative to SHP wild-type, whereas SHPG171A variant shows a diminished p53 binding. As a result of the cross-regulation, the tumor suppressor function of p53 and SHP in inhibition of colon cancer growth is compromised. Our findings reveal a unique scenario for a cross-inhibition between two tumor suppressors to keep their expression and function in check.
During IVF, non-transferred embryos are usually selected for cryopreservation on the basis of morphological criteria. This investigation evaluated an application for array comparative genomic hybridization (aCGH) in assessment of surplus embryos prior to cryopreservation.
First-time IVF patients undergoing elective single embryo transfer and having at least one extra non-transferred embryo suitable for cryopreservation were offered enrollment in the study. Patients were randomized into two groups: Patients in group A (n=55) had embryos assessed first by morphology and then by aCGH, performed on cells obtained from trophectoderm biopsy on post-fertilization day 5. Only euploid embryos were designated for cryopreservation. Patients in group B (n=48) had embryos assessed by morphology alone, with only good morphology embryos considered suitable for cryopreservation.
Among biopsied embryos in group A (n=425), euploidy was confirmed in 226 (53.1%). After fresh single embryo transfer, 64 (28.3%) surplus euploid embryos were cryopreserved for 51 patients (92.7%). In group B, 389 good morphology blastocysts were identified and a single top quality blastocyst was selected for fresh transfer. All group B patients (48/48) had at least one blastocyst remaining for cryopreservation. A total of 157 (40.4%) blastocysts were frozen in this group, a significantly larger proportion than was cryopreserved in group A (p=0.017, by chi-squared analysis).
While aCGH and subsequent frozen embryo transfer are currently used to screen embryos, this is the first investigation to quantify the impact of aCGH specifically on embryo cryopreservation. Incorporation of aCGH screening significantly reduced the total number of cryopreserved blastocysts compared to when suitability for freezing was determined by morphology only. IVF patients should be counseled that the benefits of aCGH screening will likely come at the cost of sharply limiting the number of surplus embryos available for cryopreservation.
Fertilization in vitro; Comparative genomic hybridization; Preimplantation genetic diagnosis; Cryopreservation
Single embryo transfer (SET) remains underutilized as a strategy to reduce multiple gestation risk in IVF, and its overall lower pregnancy rate underscores the need for improved techniques to select one embryo for fresh transfer. This study explored use of comprehensive chromosomal screening by array CGH (aCGH) to provide this advantage and improve pregnancy rate from SET.
First-time IVF patients with a good prognosis (age <35, no prior miscarriage) and normal karyotype seeking elective SET were prospectively randomized into two groups: In Group A, embryos were selected on the basis of morphology and comprehensive chromosomal screening via aCGH (from d5 trophectoderm biopsy) while Group B embryos were assessed by morphology only. All patients had a single fresh blastocyst transferred on d6. Laboratory parameters and clinical pregnancy rates were compared between the two groups.
For patients in Group A (n = 55), 425 blastocysts were biopsied and analyzed via aCGH (7.7 blastocysts/patient). Aneuploidy was detected in 191/425 (44.9%) of blastocysts in this group. For patients in Group B (n = 48), 389 blastocysts were microscopically examined (8.1 blastocysts/patient). Clinical pregnancy rate was significantly higher in the morphology + aCGH group compared to the morphology-only group (70.9 and 45.8%, respectively; p = 0.017); ongoing pregnancy rate for Groups A and B were 69.1 vs. 41.7%, respectively (p = 0.009). There were no twin pregnancies.
Although aCGH followed by frozen embryo transfer has been used to screen at risk embryos (e.g., known parental chromosomal translocation or history of recurrent pregnancy loss), this is the first description of aCGH fully integrated with a clinical IVF program to select single blastocysts for fresh SET in good prognosis patients. The observed aneuploidy rate (44.9%) among biopsied blastocysts highlights the inherent imprecision of SET when conventional morphology is used alone. Embryos randomized to the aCGH group implanted with greater efficiency, resulted in clinical pregnancy more often, and yielded a lower miscarriage rate than those selected without aCGH. Additional studies are needed to verify our pilot data and confirm a role for on-site, rapid aCGH for IVF patients contemplating fresh SET.