Carotenoids as regulators for inter-species difference in cytochrome P450 1A expression and activity in ungulates and rats

A comprehensive review on carotenoids in foods and feeds: status quo, applications, patents, and research needs

Carotenoids are isoprenoids widely distributed in foods that have been always part of the diet of humans. Unlike the other so-called food bioactives, some carotenoids can be converted into retinoids exhibiting vitamin A activity, which is essential for humans. Furthermore, they are much more versatile as they are relevant in foods not only as sources of vitamin A, but also as natural pigments, antioxidants, and health-promoting compounds. Lately, they are also attracting interest in the context of nutricosmetics, as they have been shown to provide cosmetic benefits when ingested in appropriate amounts. In this work, resulting from the collaborative work of participants of the COST Action European network to advance carotenoid research and applications in agro-food and health (EUROCAROTEN, www.eurocaroten.eu, https://www.cost.eu/actions/CA15136/#tabs|Name:overview) research on carotenoids in foods and feeds is thoroughly reviewed covering aspects such as analysis, carotenoid food sources, carotenoid databases, effect of processing and storage conditions, new trends in carotenoid extraction, daily intakes, use as human, and feed additives are addressed. Furthermore, classical and recent patents regarding the obtaining and formulation of carotenoids for several purposes are pinpointed and briefly discussed. Lastly, emerging research lines as well as research needs are highlighted.

Induction of proliferative and mutagenic activity by benzo(a)pyrene in PC-3 cells via JAK2/STAT3 pathway

Environmental carcinogen benzo(a)pyrene (BaP) is a representative compound of polycyclic aromatic hydrocarbons (PAHs). BaP is strongly associated with prostate carcinogenesis. However, the molecular mechanism of BaP in development of prostate carcinoma remains largely unknown. The aim of this study was to investigate the effect and mechanism of BaP on the development in prostate cancer. PC-3 cells were exposed to different concentrations of BaP for 24, 48, 72 h, respectively. We analyzed the effect of BaP on PC-3 cell viability, cell cycle, DNA strand breaks, mutagenic activity, and migration. The expression of associated regulatory genes and the effect of JAK2/STAT3 signaling were also measured to explore the relationships among BaP metabolism, the JAK2/STAT3 pathway and proliferative activity in PC-3 cells. We observed significant effects on proliferation, DNA strand breaks and mutagenic activity after BaP exposure in PC-3 cells, and inhibitors of CYP1 and the AhR transcription factor α -naphthoflavone (ANF) and CH223191 treatment clearly reduced both cell survival and mutagenesis associated with BaP exposure. Reduction in G0-G1 phase population and elevation in S phase were observed after BaP exposure. Migratory cells for PC-3 were significantly increased. The results were further confirmed by the expression of mRNA levels in the significant increments of Snail, Slug, MMP-9, CYP1A1, CYP1B1, CycilnD1, CDK4 and significant reduction of E-cadherin. Significant enhancements were found in the expression of JAK2, STAT3 after BaP treatment. Additionally, activator IL-6 significantly enhanced the effect of BaP on cell survival, mutagenic activity, Cyclin D1, CDK4, Snail, and JAK2/STAT3 expression in PC-3 cells. Significant reductions in cell survival, mutagenic activity, Cyclin D1, CDK4, Snail, and JAK2/STAT3 expression were found after inhibitor AG490, ANF and CHJ223191 treatment. These findings reveal that BaP enhances the proliferative and mutagenic activity via JAK2-STAT3 pathway in PC-3 cells, and provide the additional evidence to understand the crucial role of BaP in prostate cancer carcinogenesis.

Effects of Pyrene on Human Liver HepG2 Cells: Cytotoxicity, Oxidative Stress, and Transcriptomic Changes in Xenobiotic Metabolizing Enzymes and Inflammatory Markers with Protection Trial Using Lycopene

Pyrene is one of the major polycyclic aromatic hydrocarbons formed during heat treatment of meat and in car exhausts; however, few studies have investigated pyrene-induced adverse effects on human cell lines. This study aimed at the investigation of pyrene-induced cytotoxicity and oxidative damage in human liver HepG2 cells at environmentally relevant concentrations. Pyrene-induced changes in mRNA expression of xenobiotic metabolizing enzymes (XMEs), xenobiotic transporters, antioxidant enzymes, and inflammatory markers were investigated using real-time PCR. As a protection trial, the ameliorative effects of lycopene, a carotenoid abundantly found in tomato, were investigated. The possible mechanisms behind such effects were examined via studying the co exposure effects of pyrene and lycopene on regulatory elements including the aryl hydrocarbon receptor (Air) and elytroid 2-related factor 2 (RF). The achieved results indicated that pyrene caused significant cytotoxicity at 50 n, with a clear production of reactive oxygen species (ROS) in a dose-dependent manner. Pyrene upregulated mRNA expression of phase I enzymes including CYP1A1, 1A2, and CYP1B1 and inflammatory markers including TNFα and Cox2. However, pyrene significantly downregulated phase II enzymes, xenobiotic transporters, and antioxidant enzymes. Interestingly, lycopene significantly reduced pyrene-induced cytotoxicity and ROS production. Moreover, lycopene upregulated detoxification and antioxidant enzymes, probably via its regulatory effects on Air- and RF-dependent pathways.

Determination of polycyclic aromatic hydrocarbon content in heat-treated meat retailed in Egypt: Health risk assessment, benzo[a]pyrene induced mutagenicity and oxidative stress in human colon (CaCo-2) cells and protection using rosmarinic and ascorbic acids

This study was undertaken to estimate the concentrations of the formed polycyclic aromatic hydrocarbons (PAHs) in heat-treated (boiled, pan-fried and grilled) meats collected from Egypt. Dietary intakes and cancer risks of PAHs among Egyptian adults were calculated. Benzo[a]pyrene (B[a]P)-induced mutagenicity and oxidative stress in human colon (CaCo-2) cell line and mechanisms behind such effects were also investigated. Finally, protection trials using rosmarinic (RMA) and ascorbic acids (ASA) were carried out. The results indicated formation of PAHs at high levels in the heat-treated meats. Calculated incremental life time cancer risk among Egyptian adults were 7.05179E-07, 7.00604 E-06 and 1.86069 E-05 due to ingestion of boiled, pan-fried and grilled meats, respectively. B[a]P-exposed CaCo-2 cells had high abilities for mutagenicity (490.05 ± 21.37 His + revertants) and production of reactive oxygen species. RMA and ASA protected CaCo-2 cells via reduction of B[a]P-induced mutagenicity and oxidative stress and upregulation of phase II detoxification enzymes and xenobiotic transporters.

Investigation of mRNA expression changes associated with field exposure to DDTs in chickens from KwaZulu-Natal, South Africa

The objective of this study was to identify potential mRNA expression changes in chicken livers associated with environmental exposure to dichloro-diphenyl-trichloroethane (DDT) and its metabolites (DDTs). In particular, we focused on genes relating to the immune system and metabolism. We analyzed liver samples from free-ranging chickens in KwaZulu-Natal, South Africa, for contamination by DDTs. This area predominantly uses DDT in its malaria control program, and homes are sprayed annually with the pesticide. Genes relating to the immune system and metabolism were selected as potential genetic biomarkers that could be linked to higher contamination with DDTs. RT-qPCR analysis on 39 samples showed strong correlations between DDTs contamination and mRNA expression for the following genes: AvBD1, AvBD2, AvBD6 and AvBD7 (down-regulated), and CYP17, ELOVL2 and SQLE (up-regulated). This study shows for the first time interesting and significant correlations between genetic material collected from environmentally-exposed chickens and mRNA expression of several genes involved in immunity and metabolism. These findings show the usefulness of analysis on field samples from a region with high levels of environmental contamination in detecting potential biomarkers of exposure. In particular, we observed clear effects from DDT contamination on mRNA expression of genes involved in immune suppression, endocrine-disrupting effects, and lipid dysregulation. These results are of interest in guiding future studies to further elucidate the pathways involved in and clinical importance of toxicity associated with DDT exposure from contaminated environments, to ascertain the health risk to livestock and any subsequent risks to food security for people.

β-carotene and retinol reduce benzo[a]pyrene-induced mutagenicity and oxidative stress via transcriptional modulation of xenobiotic metabolizing enzymes in human HepG2 cell line

Benzo[a]pyrene (B[a]P) is one of the polycyclic aromatic hydrocarbons which is formed due to smoking of foods, incomplete combustion of woods, vehicle exhausts, and cigarettes smokes. B[a]P gets entry into human and animal bodies mainly through their diets. Metabolic activation of B[a]P is required to induce mutagenesis and carcinogenesis in animal and human studies. Carotenoids and retinoids are phytochemicals that if ingested have multiple physiological interferences in the human and animal bodies. In this study, we firstly investigated the protective effects of β-carotene, β-apo-8-carotenal, retinol, and retinoic acid against B[a]P-induced mutagenicity and oxidative stress in human HepG2 cells. Secondly, we tested the hypothesis of modulating xenobiotic metabolizing enzymes (XMEs) by carotenoids and retinoids as a possible mechanism of protection by these micronutrients against B[a]P adverse effects. The obtained results declared that β-carotene and retinol significantly reduced B[a]P-induced mutagenicity and oxidative stress. Tested carotenoids and retinoids reduced B[a]P-induced phase I XMEs and induced B[a]P reduced phase II and III XMEs. Thus, the protective effects of these micronutrients are probably due to their ability of induction of phase II and III enzymes and interference with the induction of phase I enzymes by the promutagen, B[a]P. It is highly recommended to consume foods rich in these micronutrients in the areas of high PAH pollution.

The African hedgehog (Atelerix albiventris): Low phase I and phase II metabolism activities

The African hedgehog, Atelerix albiventris, is a spiny mammal that has become popular as an exotic pet in many countries. To elucidate the ability of hedgehogs to metabolize xenobiotics, the animals were exposed to polycyclic aromatic hydrocarbon, pyrene. The in vivo exposure study indicated that pyrene was biotransformed to glucuronide and sulfate conjugates, such as pyrene-1-glucuronide, pyrene-1-sulfate, and pyrenediol-sulfate, and excreted in the urine. Pyrene-1-glucuronide was the main metabolite, and limited sulfate conjugate excretion was observed. The main products excreted in feces were 1-hydroxypyrene and pyrene. Based on the results of the in vivo exposure study, in vitro enzymatic kinetic experiments were performed using various substrates and compared to rats and pigs. The enzyme efficiencies of cytochrome P450 (CYP)-mediated ethoxyresorufin O-deethylase activity and warfarin 4'-, 6-, and 8-hydroxylation activity in hedgehogs were lower than those of rats. Furthermore, UDP-glucuronosyltransferase activity in hedgehogs also had a lower K_m value than that in pigs. Interestingly, the enzyme efficiencies of sulfation activity toward 1-hydroxypyrene and β-estradiol in hedgehogs were significantly lower than those in pigs. These observations suggested that phenol and estrogen sulfotransferases may have limited roles in xenobiotic metabolism in hedgehogs.

Strain differences in cytochrome P450 mRNA and protein expression, and enzymatic activity among Sprague Dawley, Wistar, Brown Norway and Dark Agouti rats

Rat cytochrome P450 (CYP) exhibits inter-strain differences, but their analysis has been scattered across studies under different conditions. To identify these strain differences in CYP more comprehensively, mRNA expression, protein expression and metabolic activity among Wistar (WI), Sprague Dawley (SD), Dark Agouti (DA) and Brown Norway (BN) rats were compared. The mRNA level and enzymatic activity of CYP1A1 were highest in SD rats. The rank order of Cyp3a2 mRNA expression mirrored its protein expression, i.e., DA>BN>SD>WI, and was similar to the CYP3A2-dependent warfarin metabolic activity, i.e., DA>SD>BN>WI. These results suggest that the strain differences in CYP3A2 enzymatic activity are caused by differences in mRNA expression. Cyp2b1 mRNA levels, which were higher in DA rats, did not correlate with its protein expression or enzymatic activity. This suggests that the strain differences in enzymatic activity are not related to Cyp2b1 mRNA expression. In conclusion, WI rats tended to have the lowest CYP1A1, 2B1 and 3A2 mRNA expression, protein expression and enzymatic activity among the strains. In addition, SD rats had the highest CYP1A1 mRNA expression and activity, while DA rats had higher CYP2B1 and CYP3A2 mRNA and protein expression. These inter-strain differences in CYP could influence pharmacokinetic considerations in preclinical toxicological studies.

β-carotene and retinol contents in the meat of herbivorous ungulates with a special reference to their public health importance

The aim of this study was to estimate total carotenoids, β-carotene and retinol concentrations in the livers and muscles of some ungulates (cattle, buffalo, sheep, goats and horses) in comparison with the Wistar rats as a control. Cattle and horses had the highest contents of total carotenoids and β-carotene. Unexpectedly, sheep was the highest accumulator of retinol with a mean concentration of 203 ± 23.34 µg/g, while the least accumulator was buffalo, having a mean value of 58.28 ± 13.77 µg/g. Livers had higher contents of the examined phytochemicals than muscles. Consumption of these tissues may provide human with some needs from these important phytochemicals, though ingestion of livers, especially that of the sheep, is not advisable for the pregnant women.

The effect of copper on the mRNA expression profile of xenobiotic-metabolizing enzymes in cultured rat H4-II-E cells

Copper (Cu(2+)) is an essential element that plays important roles in physiological functions of the body. However, high Cu(2+) levels can have toxic implications. This study aims to investigate the constitutive response to Cu(2+) exposure of xenobiotic-metabolizing enzymes in cultured rat liver (H4-II-E) cell lines. Rat cells were exposed to copper sulfate (0-500 μM) for 24 h. The effects of Cu(2+) on the messenger RNA (mRNA) expressions of phase I and II enzymes and regulatory elements were examined using real-time PCR. Metallothionein mRNA expression was induced in a dose-dependent manner after treatment with Cu(2+). mRNA expressions of phase I enzymes such as cytochrome P450 1A1 and 1A2 (CYP1A1 and CYP1A2) were slightly induced after exposure to low concentrations of Cu(2+); however, CYP1A1 and CYP1A2 mRNA expressions were significantly downregulated at higher Cu(2+) concentrations. These effects corresponded with expression of aryl hydrocarbon receptor mRNA. The mRNA expressions of phase II enzymes were reduced upon exposure to Cu(2+). In conclusion, phase I and II enzyme expressions were significantly modulated upon Cu(2+) exposure. These results indicated that Cu(2+) exposure had toxicological implications for cultured H4-II-E cells.

Expression alterations of cytochromes P4501A1, 2E1, and 3A, and their receptors AhR and PXR caused by 1-octyl-3-methylimidazolium chloride in mouse mammary carcinoma cells

Cytochrome P450s (CYPs) play a key role in the metabolism of a wide range of environmental xenobiotics and endogenous compounds. The expression and activity levels of CYPs can be elevated by a process of induction involving the activation of nuclear receptors. The effects of the ionic liquid 1-octyl-3-methylimidazolium chloride ([C(8)mim][Cl]) on the expression of cytochrome P450 members, including CYP1A1, CYP2E1, and CYP3A, as well as on aryl hydrocarbon receptor (AhR) and pregnane X receptor (PXR) in mouse mammary carcinoma cells (EMT6) were investigated by using quantitative real-time PCR in the present study. The results reveal that [C(8)mim][Cl]-exposure up-regulates the expressions of CYP1A1, CYP2E1, and CYP3A at mRNA level, suggesting that imidazolium-based ionic liquids can activate CYPs. Our results also suggest that [C(8)mim][Cl]-mediated CYP3A induction be PXR-dependent. This result may be beneficial to evaluating the environmental toxicity of imidazolium-based ionic liquids and investigating the metabolism of imidazolium-derivative drugs.