miRNA as molecular target of polyphenols underlying their biological effects

Targeting miRNAs by polyphenols: Novel therapeutic strategy for cancer

In the recent years, polyphenols have gained significant attention in scientific community owing to their potential anticancer effects against a wide range of human malignancies. Epidemiological, clinical and preclinical studies have supported that daily intake of polyphenol-rich dietary fruits have a strong co-relationship in the prevention of different types of cancer. In addition to direct antioxidant mechanisms, they also regulate several therapeutically important oncogenic signaling and transcription factors. However, after the discovery of microRNA (miRNA), numerous studies have identified that polyphenols, including epigallocatechin-3-gallate, genistein, resveratrol and curcumin exert their anticancer effects by regulating different miRNAs which are implicated in all the stages of cancer. MiRNAs are short, non-coding endogenous RNA, which silence the gene functions by targeting messenger RNA (mRNA) through degradation or translation repression. However, cancer associated miRNAs has emerged only in recent years to support its applications in cancer therapy. Preclinical experiments have suggested that deregulation of single miRNA is sufficient for neoplastic transformation of cells. Indeed, the widespread deregulation of several miRNA profiles of tumor and healthy tissue samples revealed the involvement of many types of miRNA in the development of numerous cancers. Hence, targeting the miRNAs using polyphenols will be a novel and promising strategy in anticancer chemotherapy. Herein, we have critically reviewed the potential applications of polyphenols on various human miRNAs, especially which are involved in oncogenic and tumor suppressor pathways.

Nutrition, microRNAs, and Human Health

MicroRNAs (miRs) hybridize with complementary sequences in mRNA and silence genes by destabilizing mRNA or preventing translation of mRNA. Over 60% of human protein-coding genes are regulated by miRs, and 1881 high-confidence miRs are encoded in the human genome. Evidence suggests that miRs not only are synthesized endogenously, but also might be obtained from dietary sources, and that food compounds alter the expression of endogenous miR genes. The main food matrices for studies of biological activity of dietary miRs include plant foods and cow milk. Encapsulation of miRs in exosomes and exosome-like particles confers protection against RNA degradation and creates a pathway for intestinal and vascular endothelial transport by endocytosis, as well as delivery to peripheral tissues. Evidence suggests that the amount of miRs absorbed from nutritionally relevant quantities of foods is sufficient to elicit biological effects, and that endogenous synthesis of miRs is insufficient to compensate for dietary miR depletion and rescue wild-type phenotypes. In addition, nutrition alters the expression of endogenous miR genes, thereby compounding the effects of nutrition-miR interactions in gene regulation and disease diagnosis in liquid biopsies. For example, food components and dietary preferences may modulate serum miR profiles that may influence biological processes. The complex crosstalk between nutrition, miRs, and gene targets poses a challenge to gene network analysis and studies of human disease. Novel pipelines and databases have been developed recently, including a dietary miR database for archiving reported miRs in 15 dietary resources. miRs derived from diet and endogenous synthesis have been implicated in physiologic and pathologic conditions, including those linked with nutrition and metabolism. In fact, several miRs are actively regulated in response to overnutrition and tissue inflammation, and are involved in facilitating the development of chronic inflammation by modulating tissue-infiltrated immune cell function.

Role of fruits, nuts, and vegetables in maintaining cognitive health

Population aging is leading to an increase in the incidence of age-related cognitive dysfunction and, with it, the health care burden of caring for older adults. Epidemiological studies have shown that consumption of fruits, nuts, and vegetables is positively associated with cognitive ability; however, these foods, which contain a variety of neuroprotective phytochemicals, are widely under-consumed. Surprisingly few studies have investigated the effects of individual plant foods on cognitive health but recent clinical trials have shown that dietary supplementation with individual foods, or switching to a diet rich in several of these foods, can improve cognitive ability. While additional research is needed, increasing fruit, nut, and vegetable intake may be an effective strategy to prevent or delay the onset of cognitive dysfunction during aging.

Nutritionally relevant concentrations of resveratrol and hydroxytyrosol mitigate oxidative burst of human granulocytes and monocytes and the production of pro-inflammatory mediators in LPS-stimulated RAW 264.7 macrophages

The health benefits of bio-active phenolic compounds have been largely investigated in vitro at concentrations which exceed those reachable in vivo. We investigated and compared the anti-inflammatory effects of resveratrol, hydroxytyrosol and oleuropein at physiologically relevant concentrations by using in vitro models of inflammation. Human granulocytes and monocytes were stimulated with phorbol myristate acetate (PMA) and the ability of resveratrol, hydroxytyrosol and oleuropein to inhibit the oxidative burst and CD11b expression was measured. Nitric oxide (NO), prostaglandin E2 (PGE2) levels, COX-2, iNOS, TNFα, IL-1β and miR-146a expression and activation of the transcription factor Nrf2 were evaluated in macrophages RAW 264.7 stimulated with LPS (1μg/ml) for 18h, exposed to resveratrol, hydroxytyrosol and oleuropein (5 and 10μM). Synergistic effects were explored as well, together with the levels of PGE2, COX-2 and IL-1β expression in macrophages after 6h of LPS stimulation. PGE2 and COX-2 expression were also assessed on human monocytes. All the tested compounds inhibited granulocytes oxidative burst in a concentration dependent manner and CD11b expression was also significantly counteracted by resveratrol and hydroxytyrosol. The measurement of oxidative burst in human monocytes produced similar effects being resveratrol more active. Hydroxytyrosol and resveratrol inhibited the production of NO and PGE2 but did not reduce iNOS, TNFα or IL-1β gene expression in LPS-stimulated RAW 264.7 for 18h. Resveratrol slightly decreased COX-2 expression after 18h but not after 6h, but reduced PGE2 levels after 6h. Resveratrol and hydroxytyrosol 10μM induced NRf2 nuclear translocation and reduced miR-146a expression in LPS treated RAW 264.7. Overall, we reported an anti-inflammatory effect of resveratrol and hydroxytyrosol at low, nutritionally relevant concentrations, involving the inhibition of granulocytes and monocytes activation, the modulation of miR-146a expression and the activation of Nrf2. A regular dietary intake of resveratrol and hydroxytyrosol may be a useful complementary strategy to control inflammatory diseases.

Quercetin as an Emerging Anti-Melanoma Agent: A Four-Focus Area Therapeutic Development Strategy

Replacing current refractory treatments for melanoma with new prevention and therapeutic approaches is crucial in order to successfully treat this aggressive cancer form. Melanoma develops from neural crest cells, which express tyrosinase – a key enzyme in the pigmentation pathway. The tyrosinase enzyme is highly active in melanoma cells and metabolizes polyphenolic compounds; tyrosinase expression thus makes feasible a target for polyphenol-based therapies. For example, quercetin (3,3′,4′,5,7-pentahydroxyflavone) is a highly ubiquitous and well-classified dietary polyphenol found in various fruits, vegetables, and other plant products including onions, broccoli, kale, oranges, blueberries, apples, and tea. Quercetin has demonstrated antiproliferative and proapoptotic activity in various cancer cell types. Quercetin is readily metabolized by tyrosinase into various compounds that promote anticancer activity; additionally, given that tyrosinase expression increases during tumorigenesis, and its activity is associated with pigmentation changes in both early- and late-stage melanocytic lesions, it suggests that quercetin can be used to target melanoma. In this review, we explore the potential of quercetin as an anti-melanoma agent utilizing and extrapolating on evidence from previous in vitro studies in various human malignant cell lines and propose a “four-focus area strategy” to develop quercetin as a targeted anti-melanoma compound for use as either a preventative or therapeutic agent. The four areas of focus include utilizing quercetin to (i) modulate cellular bioreduction potential and associated signaling cascades, (ii) affect transcription of relevant genes, (iii) regulate epigenetic processes, and (iv) develop effective combination therapies and delivery modalities/protocols. In general, quercetin could be used to exploit tyrosinase activity to prevent, and/or treat, melanoma with minimal additional side effects.

Methylated urolithin A, the modified ellagitannin-derived metabolite, suppresses cell viability of DU145 human prostate cancer cells via targeting miR-21

Urolithins are bioactive ellagic acid-derived metabolites produced by human colonic microflora. Although previous studies have demonstrated the cytotoxicity of urolithins, the effect of urolithins on miRNAs is still unclear. In this study, the suppressing effects of methylated urolithin A (mUA) on cell viability in human prostate cancer DU145 cells was investigated. mUA induced caspase-dependent cell apoptosis, mitochondrial depolarization and down-regulation of Bcl-2/Bax ratio. The results showed that upon exposure to mUA, miR-21 expression was decreased and the expression of PTEN and Pdcd4 protein was elevated. mUA could further suppress Akt phosphorylation and increase protein expression of FOXO3a, and the effects of mUA on Akt phosphorylation and protein expression of FOXO3a were blocked by PTEN silence. Moreover, mUA suppressed the Wnt/β-catenin-mediated transcriptional activation of MMP-7 and c-Myc, and this function of mUA on MMP-7 and c-Myc was attenuated by over-expression of miR-21. In conclusion, our data suggest that mUA can suppress cell viability in DU145 cells through modulating miR-21 and its downstream series-wound targets, including PTEN, Akt and Wnt/β-catenin signaling.

An update on the role of nutrigenomic modulations in mediating the cardiovascular protective effect of fruit polyphenols

Polyphenols are plant food microconstituents that are widely distributed in the human diet, with fruits and fruit-derived products as one of the main dietary sources. Epidemiological studies have shown an inverse relationship between the intake of different classes of polyphenols and the risk of myocardial infarction or cardiovascular disease (CVD) mortality. These compounds have been associated with the promotion of cardiovascular health as evidenced by clinical studies reporting beneficial effects of polyphenol-rich fruit consumption on intermediate markers of cardiovascular diseases. Additionally, animal and in vitro studies have indicated positive roles of polyphenols in preventing dysfunctions associated with the development of cardiovascular diseases. However, the mechanisms of action underlying their beneficial effects appear complex and are not fully understood. This review aims to provide an update on the nutrigenomic effects of different groups of polyphenols from fruits and especially focuses on their cardiovascular protective effects in cell and animal studies.

Resveratrol and pterostilbene epigenetically restore PTEN expression by targeting oncomiRs of the miR-17 family in prostate cancer

In recent years, not only has the role of miRNAs in cancer become increasingly clear but also their utilization as potential biomarkers and therapeutic targets has gained ground. Although the importance of dietary stilbenes such as resveratrol and pterostilbene as anti-cancer agents is well recognized, our understanding of their miRNA-targeting capabilities is still limited. In our previous study, we reported that resveratrol downregulates PTEN-targeting members of the oncogenic miR-17 family, which are overexpressed in prostate cancer. This study investigates the resveratrol and pterostilbene induced miRNA-mediated regulation of PTEN in prostate cancer. Here, we show that both compounds decrease the levels of endogenous as well as exogenously expressed miR-17, miR-20a and miR-106b thereby upregulating their target PTEN. Using functional luciferase reporter assays, we demonstrate that ectopically expressed miR-17, miR-20a and miR-106b directly target PTEN 3′UTR to reduce its expression, an effect rescued upon treatment with resveratrol and pterostilbene. Moreover, while stable lentiviral expression of miR-17/106a significantly decreased PTEN mRNA and protein levels and conferred survival advantage to the cells, resveratrol and more so pterostilbene was able to dramatically suppress these effects. Further, pterostilbene through downregulation of miR-17-5p and miR-106a-5p expression both in tumors and systemic circulation, rescued PTEN mRNA and protein levels leading to reduced tumor growth in vivo. Our findings implicate dietary stilbenes as an attractive miRNA-mediated chemopreventive and therapeutic strategy, and circulating miRNAs as potential chemopreventive and predictive biomarkers for clinical development in prostate cancer.

Understanding of tolerance in TRAIL-induced apoptosis and cancelation of its machinery by α-mangostin, a xanthone derivative

Tumor necrosis-factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF-superfamily that selectively induces apoptosis through death receptors (DRs) 4 and/or 5 in cancer cells. These receptors are expressed on the cancer cell surface, without affecting normal cells. Unfortunately, many clinical studies have shown that cancer cells acquire TRAIL-resistance and finally avoid TRAIL-induced apoptosis. The detailed mechanisms of this resistance are not well understood. In the current study, we established a TRAIL-resistant human colon cancer DLD-1 cell line to clarify the mechanisms of TRAIL-resistance and developed agents to cancel its machinery. Also, we found that cancer stem-like cells from breast epithelial proliferating MCF10A cells were also sensitive to TRAIL-induced apoptosis. The enforced expression of DR5 in both TRAIL-resistant cells partially recovered the sensitivity to the TRAIL ligand, which was judged by the activation of caspase-8. As a result, we newly found that the mechanisms of TRAIL-resistance comprised co-existence of a decrease in the expression level of DR5 along with malfunction of its recruitment to the cell surface, as evidenced by Western blot and immunocytological analysis, respectively. Interestingly, α-mangostin, which is a xanthone derivative, canceled the resistance by increasing the expression level of DR5 through down-regulation of miR-133b and effectively induced the translocation of DR5 to the cancer cell surface membrane in TRAIL-resistant DLD-1 cells. These findings indicate that α-mangostin functioned as a sensitizer of TRAIL-induced apoptosis and may thus serve as a possible adjuvant compound for cytokine therapy to conquer TRAIL-resistance.

P38 MAPK/miR-1 are involved in the protective effect of EGCG in high glucose-induced Cx43 downregulation in neonatal rat cardiomyocytes

The remodeling of cardiac gap junctions contributes to various arrhythmias in a diabetic heart. We previously reported that Epigallocatechin-3-gallate (EGCG) attenuated connexin43 (Cx43) protein downregulation induced by high glucose (HG) in neonatal rat cardiomyocytes, but Cx43 mRNA expression was not affected. It indicated the possible mechanisms of post-transcriptional regulation, which still remains unclear. As microRNAs (miRNAs) regulate gene expression widely at post-transcriptional level, we measured miR-1/206 in cardiomyocytes treated with HG and EGCG by quantitative RT-PCR and investigated their relationship with signal transduction pathways. The results showed that HG induced miR-1/206 elevation by PKC MAPK pathway. Moreover, we tested the negative regulation effect of miR-1/206 on Cx43 protein by miRNAs transfection. EGCG, however, nearly abolished the HG-induced miR-1 augmentation via P38 MAPK pathway. Therefore, our study suggested that PKC-activated miR-1/206 expression might contribute to Cx43 downregulation in HG-treated cardiomyocytes, and EGCG conferred protective effect by inhibiting miR-1 elevation via P38 MAPK pathway.

Cynara scolymus affects malignant pleural mesothelioma by promoting apoptosis and restraining invasion

Malignant pleural mesothelioma is a poorly treated neoplasia arising from the pleural mesothelial lining. Here we document that the leaf extract of Cynara scolymus exerts broad antitumoral effects both in vitro and in vivo on mesothelioma cell lines. We found that Cynara scolymus treatment affects strongly cell growth, migration and tumor engraftment of mesothelioma cell lines. Strikingly, dietary feeding with Cynara scolymus leaf extract reduces the growth of mesothelioma xenografted tumors similarly to pemetrexed, a commonly employed drug in the treatment of mesothelioma. In aggregate our findings suggest that leaf extract of Cynara scolymus holds therapeutic potential for the treatment of mesothelioma.

Regulatory mechanisms of microRNA expression

MicroRNAs (miRs, miRNAs) are small molecules of 18-22 nucleotides that serve as important regulators of gene expression at the post-transcriptional level. One of the mechanisms through which miRNAs regulate gene expression involves the interaction of their "seed" sequences primarily with 3'-end and more rarely with 5'-end, of mRNA transcribed from target genes. Numerous studies over the past decade have been devoted to quantitative and qualitative assessment of miRNAs expression and have shown remarkable changes in miRNA expression profiles in various diseases. Thus, profiling of miRNA expression can be an important tool for diagnostics and treatment of disease. However, less attention has been paid towards understanding the underlying reasons for changes in miRNA expression, especially in cancer cells. The purpose of this review is to analyze and systematize current data that explains reasons for changes in the expression of miRNAs. The review will cover both transcriptional (changes in gene expression and promoter hypermethylation) and post-transcriptional (changes in miRNA processing) mechanisms of regulation of miRNA expression, as well as effects of endogenous (hormones, cytokines) and exogenous (xenobiotics) compounds on the miRNA expression. The review will summarize the complex multilevel regulation of miRNA expression, in relation to cell type, physiological state of the body and various external factors.

How Diet Intervention via Modulation of DNA Damage Response through MicroRNAs May Have an Effect on Cancer Prevention and Aging, an in Silico Study

The DNA damage response (DDR) is a molecular mechanism that cells have evolved to sense DNA damage (DD) to promote DNA repair, or to lead to apoptosis, or cellular senescence if the damage is too extensive. Recent evidence indicates that microRNAs (miRs) play a critical role in the regulation of DDR. Dietary bioactive compounds through miRs may affect activity of numerous genes. Among the most studied bioactive compounds modulating expression of miRs are epi-gallocatechin-3-gallate, curcumin, resveratrol and n3-polyunsaturated fatty acids. To compare the impact of these dietary compounds on DD/DDR network modulation, we performed a literature search and an in silico analysis by the DIANA-mirPathv3 software. The in silico analysis allowed us to identify pathways shared by different miRs involved in DD/DDR vis-à-vis the specific compounds. The results demonstrate that certain miRs (e.g., -146, -21) play a central role in the interplay among DD/DDR and the bioactive compounds. Furthermore, some specific pathways, such as "fatty acids biosynthesis/metabolism", "extracellular matrix-receptor interaction" and "signaling regulating the pluripotency of stem cells", appear to be targeted by most miRs affected by the studied compounds. Since DD/DDR and these pathways are strongly related to aging and carcinogenesis, the present in silico results of our study suggest that monitoring the induction of specific miRs may provide the means to assess the antiaging and chemopreventive properties of particular dietary compounds.

Green tea and quercetin sensitize PC-3 xenograft prostate tumors to docetaxel chemotherapy

Background

Chemotherapy with docetaxel (Doc) remains the standard treatment for metastatic and castration-resistance prostate cancer (CRPC). However, the clinical success of Doc is limited by its chemoresistance and side effects. This study investigated whether natural products green tea (GT) and quercetin (Q) enhance the therapeutic efficacy of Doc in CRPC in mouse models.

Methods

Male severe combined immunodeficiency (SCID) mice (n = 10 per group) were inoculated with androgen-independent prostate cancer PC-3 cells subcutaneously. When tumors were established the intervention started. Mice were administered with GT + Q, Doc 5 mg/kg (LD), GT + Q + LD Doc, Doc 10 mg/kg (HD) or control. The concentration of GT polyphenols in brewed tea administered as drinking water was 0.07 % and Q was supplemented in diet at 0.4 %. Doc was intravenously injected weekly for 4 weeks, GT and Q given throughout the study.

Results

GT + Q or LD Doc slightly inhibited tumor growth compared to control. However, the combination of GT and Q with LD Doc significantly enhanced the potency of Doc 2-fold and reduced tumor growth by 62 % compared to LD Doc in 7-weeks intervention. A decrease of Ki67 and increase of cleaved caspase 7 were observed in tumors by the mixture, along with lowered blood concentrations of growth factors like VEGF and EGF. The mixture significantly elevated the levels of tumor suppressor mir15a and mir330 in tumor tissues. An increased risk of liver toxicity was only observed with HD Doc treatment.

Conclusions

These results provide a promising regimen to enhance the therapeutic effect of Doc in a less toxic manner.

Targeting MicroRNA in Cancer Using Plant-Based Proanthocyanidins

Proanthocyanidins are oligomeric flavonoids found in plant sources, most notably in apples, cinnamon, grape skin and cocoa beans. They have been also found in substantial amounts in cranberry, black currant, green tea, black tea and peanut skins. These compounds have been recently investigated for their health benefits. Proanthocyanidins have been demonstrated to have positive effects on various metabolic disorders such as inflammation, obesity, diabetes and insulin resistance. Another upcoming area of research that has gained widespread interest is microRNA (miRNA)-based anticancer therapies. MicroRNAs are short non-coding RNA segments, which plays a crucial role in RNA silencing and post-transcriptional regulation of gene expression. Currently, miRNA based anticancer therapies are being investigated either alone or in combination with current treatment methods. In this review, we summarize the current knowledge and investigate the potential of naturally occurring proanthocyanidins in modulating miRNA expression. We will also assess the strategies and challenges of using this approach as potential cancer therapeutics.

Could gestational diabetes mellitus be managed through dietary bioactive compounds? Current knowledge and future perspectives

Gestational diabetes mellitus (GDM) is a serious problem growing worldwide that needs to be addressed with urgency in consideration of the resulting severe complications for both mother and fetus. Growing evidence indicates that a healthy diet rich in fruit, vegetables, nuts, extra-virgin olive oil and fish has beneficial effects in both the prevention and management of several human diseases and metabolic disorders. In this review, we discuss the latest data concerning the effects of dietary bioactive compounds such as polyphenols and PUFA on the molecular mechanisms regulating glucose homoeostasis. Several studies, mostly based on in vitro and animal models, indicate that dietary polyphenols, mainly flavonoids, positively modulate the insulin signalling pathway by attenuating hyperglycaemia and insulin resistance, reducing inflammatory adipokines, and modifying microRNA (miRNA) profiles. Very few data about the influence of dietary exposure on GDM outcomes are available, although this approach deserves careful consideration. Further investigation, which includes exploring the ‘omics’ world, is needed to better understand the complex interaction between dietary compounds and GDM.

Salvianolic Acid B Restored Impaired Barrier Function via Downregulation of MLCK by microRNA-1 in Rat Colitis Model

Salvianolic acid B (Sal B) is isolated from the traditional Chinese medical herb Salvia miltiorrhiza and is reported to have a wide range of therapeutic benefits. The aim of this study was to investigate the effects of Sal B on epithelial barrier dysfunction in rat colitis and to uncover related mechanisms. Rat colitis model was established by intracolonic administration of 2, 4, 6-trinitrobenzene sulfonic acid (TNBS). The intestinal barrier function was evaluated by measuring the serum recovery of fluorescein isothiocyanate-4 kD dextran in vivo and transepithelial electrical resistance in vitro respectively. The protein expression related to intestinal barrier function was studied using western blotting. The effects of Sal B on inflammatory responses, oxidative damage and colitis recurrence were also studied in this study. The intestinal barrier dysfunction in colitis was reversed by Sal B, accompanied with the decrease of tight junction proteins, and the effect could be blocked by microRNA-1(miR-1) inhibition. The inflammatory responses, oxidative damage and colitis recurrence were also decreased by Sal B. The colitis symptoms and recurrences were ameliorated by Sal B, and restoration of impaired barrier function via downregulation of MLCK by miR-1 maybe involved in this effect. This study provides some novel insights into both of the pathological mechanisms and treatment alternatives of inflammatory bowel disease.

Involvement of miR-539-5p in the inhibition of de novo lipogenesis induced by resveratrol in white adipose tissue

Proposed miRNA mechanisms of action of resveratrol in triacylglycerol metabolism changes in adipose tissue.

Effect of olive oil phenolic compounds on the expression of blood pressure-related genes in healthy individuals

PURPOSE

To investigate whether the ingestion of olive oil having different phenolic contents influences the expression of blood pressure-related genes, involved in the renin-angiotensin-aldosterone system, in healthy humans.

METHODS

A randomized, double-blind, crossover human trial with 18 healthy subjects, who ingested 25 mL/day of olive oils (1) high (366 mg/kg, HPC) and (2) low (2.7 mg/kg, LPC) in phenolic compounds for 3 weeks, preceded by 2-week washout periods. Determination of selected blood pressure-related gene expression in peripheral blood mononuclear cells (PBMNC) by qPCR, blood pressure and systemic biomarkers.

RESULTS

HPC decreased systolic blood pressure compared to pre-intervention values and to LPC, and maintained diastolic blood pressure values compared to LPC. HPC decreased ACE and NR1H2 gene expressions compared with pre-intervention values, and IL8RA gene expression compared with LPC.

CONCLUSIONS

The introduction to the diet of an extra-virgin olive oil rich in phenolic compounds modulates the expression of some of the genes related to the renin-angiotensin-aldosterone system. These changes could underlie the decrease in systolic blood pressure observed.

Phytoestrogens modulate hepcidin expression by Nrf2: Implications for dietary control of iron absorption

Hepcidin is a liver-derived antimicrobial peptide that regulates iron absorption and is also an integral part of the acute phase response. In a previous report, we found evidence that this peptide could also be induced by toxic heavy metals and xenobiotics, thus broadening its teleological role as a defensin. However it remained unclear how its sensing of disparate biotic and abiotic stressors might be integrated at the transcriptional level. We hypothesized that its function in cytoprotection may be regulated by NFE2-related factor 2 (Nrf2), the master transcriptional controller of cellular stress defenses. In this report, we show that hepcidin regulation is inextricably linked to the acute stress response through Nrf2 signaling. Nrf2 regulates hepcidin expression from a prototypical antioxidant response element in its promoter, and by synergizing with other basic leucine-zipper transcription factors. We also show that polyphenolic small molecules or phytoestrogens commonly found in fruits and vegetables including the red wine constituent resveratrol can induce hepcidin expression in vitro and post-prandially, with concomitant reductions in circulating iron levels and transferrin saturation by one such polyphenol quercetin. Furthermore, these molecules derepress hepcidin promoter activity when its transcription by Nrf2 is repressed by Keap1. Taken together, the data show that hepcidin is a prototypical antioxidant response or cytoprotective gene within the Nrf2 transcriptional circuitry. The ability of phytoestrogens to modulate hepcidin expression in vivo suggests a novel mechanism by which diet may impact iron homeostasis.

Green tea polyphenol EGCG suppresses osteosarcoma cell growth through upregulating miR-1

(-)-Epigallocatechin-3-gallate (EGCG), the most abundant and active polyphenol in green tea, has been demonstrated to have anticancer effects in a wide variety of human cancer. MicroRNAs (miRNAs) are a class of short noncoding RNAs and play important role in gene regulation and are critically involved in the pathogenesis and progression of human cancer. This study aims to investigate the effects of EGCG on osteosarcoma (OS) cells and elucidate the underlying mechanism. Cellular function assays revealed that EGCG inhibited cell proliferation, induced cell cycle arrest and promoted apoptosis of OS cells in vitro, and also inhibited the growth of transplanted tumors in vivo. By miRNA microarray and RT-qPCR analysis, miR-1 was found to be significantly upregulated in MG-63 and U-2OS treated by EGCG in dose- and time-dependent manners, and miR-1 downregulation by inhibitor mimics attenuated EGCG-induced inhibition on cell growth of OS cells. We also confirmed that miR-1 was also frequently decreased in clinical OS tumor tissues. Moreover, both EGCG and miR-1 mimic inhibited c-MET expression, and combination treatment with EGCG and c-MET inhibitor (crizotinib) had enhanced inhibitory effects on the growth of MG-63 and U-2OS cells. Taken together, these results suggest that EGCG has an anticancer effect on OS cells, at least partially, through regulating miR-1/c-MET interaction.

Shikonin inhibits adipogenic differentiation via regulation of mir-34a-FKBP1B

Shikonin is a naturally occurring naphthoquinone pigment and a major constituent present in Lithospermum erythrorhizon. Since microRNAs (miRNAs) are one of the key post-transcriptional regulators of adipogenesis, their manipulation represents a potential new strategy to inhibit adipogenesis. Our aim was to investigate shikonin-dependent inhibition of adipogenesis with an emphasis on miRNA-related processes. Mir-34a increased during induced adipogenesis, and this was suppressed in the presence of shikonin. mRNA expression of FKBP1B, a suggested target of mir-34a according to bioinformatics studies, decreased during adipogenesis, but was recovered by shikonin treatment, which reversely correlated with mir-34a expression. A mir-34a inhibitor suppressed MDI-induced adipogenesis by blocking PPARγ and C/EBPα expression, while suppression of mir-34a recovered MDI-induced down-regulation of FKBP1B expression. A mir-34a mimic decreased FKBP1B mRNA expression in 3T3-L1 preadipocytes. We also observed that mir-34a bound directly to the 3'-untranslated region of FKBP1B. Finally, FKBP1B overexpression attenuated MDI-induced adipogenesis, PPARγ, and C/EBPα expression. These results suggest that mir-34a regulates adipogenesis by targeting FKBP1B expression. Our findings reveal that shikonin prevents adipogenesis by blocking the mir-34a-FKBP1B pathway which represents a promising potential target for preventing obesity.

Can metabolically healthy obesity be explained by diet, genetics, and inflammation?

A substantial proportion of obese individuals do not present cardiometabolic complications such as diabetes, hypertension, or dyslipidemia. Some, but not all, prospective studies observe similar risk of cardiovascular events and all-cause mortality among individuals with this so-called "metabolically healthy obese" (MHO) phenotype, compared to the metabolically healthy normal weight or metabolically healthy non-obese phenotypes. Compared to the metabolically unhealthy obese (MUO) phenotype, MHO is often characterized by a more favorable inflammatory profile, less visceral fat, less infiltration of macrophages into adipose tissue, and smaller adipocyte cell size. Tipping the inflammation balance in adipose tissue might be particularly important for metabolic health in the obese. While the potential role of genetic predisposition or lifestyle factors such as diet in the MHO phenotype is yet to be clarified, it is well known that diet affects inflammation profile and contributes to the functionality of adipose tissue. This review will discuss genetic predisposition and the molecular mechanisms underlying the potential effect of food on the development of the metabolic phenotype characteristic of obesity.

Long non-coding RNAs expression profile in HepG2 cells reveals the potential role of long non-coding RNAs in the cholesterol metabolism

BACKGROUND

Green tea has been shown to improve cholesterol metabolism in animal studies, but the molecular mechanisms underlying this function have not been fully understood. Long non-coding RNAs (lncRNAs) have recently emerged as a major class of regulatory molecules involved in a broad range of biological processes and complex diseases. Our aim was to identify important lncRNAs that might play an important role in contributing to the benefits of epigallocatechin-3-gallate (EGCG) on cholesterol metabolism.

METHODS

Microarrays was used to reveal the lncRNA and mRNA profiles in green tea polyphenol(-)-epigallocatechin gallate in cultured human liver (HepG2) hepatocytes treated with EGCG and bioinformatic analyses of the predicted target genes were performed to identify lncRNA-mRNA targeting relationships. RNA interference was used to investigate the role of lncRNAs in cholesterol metabolism.

RESULTS

The expression levels of 15 genes related to cholesterol metabolism and 285 lncRNAs were changed by EGCG treatment. Bioinformatic analysis found five matched lncRNA-mRNA pairs for five differentially expressed lncRNAs and four differentially expressed mRNA. In particular, the lncRNA AT102202 and its potential targets mRNA-3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) were identified. Using a real-time polymerase chain reaction technique, we confirmed that EGCG down-regulated mRNA expression level of the HMGCR and up-regulated expression of AT102202. After AT102202 knockdown in HepG2, we observed that the level of HMGCR expression was significantly increased relative to the scrambled small interfering RNA control (P < 0.05).

CONCLUSIONS

Our results indicated that EGCG improved cholesterol metabolism and meanwhile changed the lncRNAs expression profile in HepG2 cells. LncRNAs may play an important role in the cholesterol metabolism.

MicroRNA-Sequence Profiling Reveals Novel Osmoregulatory MicroRNA Expression Patterns in Catadromous Eel Anguilla marmorata

MicroRNAs (miRNAs) are a class of endogenous small non-coding RNAs that regulate gene expression by post-transcriptional repression of mRNAs. Recently, several miRNAs have been confirmed to execute directly or indirectly osmoregulatory functions in fish via translational control. In order to clarify whether miRNAs play relevant roles in the osmoregulation of Anguilla marmorata, three sRNA libraries of A. marmorata during adjusting to three various salinities were sequenced by Illumina sRNA deep sequencing methods. Totally 11,339,168, 11,958,406 and 12,568,964 clear reads were obtained from 3 different libraries, respectively. Meanwhile, 34 conserved miRNAs and 613 novel miRNAs were identified using the sequence data. MiR-10b-5p, miR-181a, miR-26a-5p, miR-30d and miR-99a-5p were dominantly expressed in eels at three salinities. Totally 29 mature miRNAs were significantly up-regulated, while 72 mature miRNAs were significantly down-regulated in brackish water (10‰ salinity) compared with fresh water (0‰ salinity); 24 mature miRNAs were significantly up-regulated, while 54 mature miRNAs were significantly down-regulated in sea water (25‰ salinity) compared with fresh water. Similarly, 24 mature miRNAs were significantly up-regulated, while 45 mature miRNAs were significantly down-regulated in sea water compared with brackish water. The expression patterns of 12 dominantly expressed miRNAs were analyzed at different time points when the eels transferred from fresh water to brackish water or to sea water. These miRNAs showed differential expression patterns in eels at distinct salinities. Interestingly, miR-122, miR-140-3p and miR-10b-5p demonstrated osmoregulatory effects in certain salinities. In addition, the identification and characterization of differentially expressed miRNAs at different salinities can clarify the osmoregulatory roles of miRNAs, which will shed lights for future studies on osmoregulation in fish.

Pharmacokinetic Comparison of Soy Isoflavone Extracts in Human Plasma

The soy isoflavones daidzein and genistein produce several biological activities related to health benefits. A number of isoflavone extracts are commercially available, but there is little information concerning the specific isoflavone content of these products or differences in their bioavailability and pharmacokinetics. This study describes the development and validation of an analytical method to detect and quantify daidzein, genistein, and equol in human plasma using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The method was applied in a crossover, randomized, bioavailability study. Twelve healthy volunteers were administered the same total isoflavones dose from two isoflavone supplement preparations (Super-Absorbable Soy Isoflavones (Life Extension, USA) and Fitoladius (Merck, Spain)). The pharmacokinetic parameters (AUC0-24/dose and Cmax/dose) of the isoflavones from the two preparations differed significantly. Such differences in bioavailability and kinetics may have relevant effects on the health benefits derived from their intake.

Activation of the SIRT1/p66shc antiapoptosis pathway via carnosic acid-induced inhibition of miR-34a protects rats against nonalcoholic fatty liver disease

Recent studies have demonstrated that miR-34a expression is significantly upregulated and associated with apoptosis in nonalcoholic fatty liver disease (NAFLD). Carnosic acid (CA) is a novel antioxidant and a potential inhibitor of apoptosis in organ injury, including liver injury. This study aimed to investigate the signaling mechanisms underlying miR-34a expression and the antiapoptotic effect of CA in NAFLD. CA treatment significantly reduced the high-fat diet (HFD)-induced elevations in aminotransferase activity as well as in serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and malondialdehyde (MDA) levels but increased serum high-density lipoprotein cholesterol (HDL-C) and hepatic superoxide dismutase (SOD) levels. Moreover, CA treatment ameliorated the increase in cleaved caspase-3 caused by HFD exposure and completely reversed the HFD-induced decreases in manganese superoxide dismutase (MnSOD) and B-cell lymphoma-extra large expression. CA also counteracted the HFD- or palmitic acid (PA)-induced increases in caspase-3 and caspase-9 activity. Mechanistically, CA reversed the HFD- or PA-induced upregulation of miR-34a, which is the best-characterized regulator of SIRT1. Importantly, the decrease in miR-34a expression was closely associated with the activation of the SIRT1/p66shc pathway, which attenuates hepatocyte apoptosis in liver ischemia/reperfusion injury. A dual luciferase assay in L02 cells validated the modulation of SIRT1 by CA, which occurs at least partly via miR-34a. In addition, miR-34a overexpression was significantly counteracted by CA, which prevented the miR-34a-dependent repression of the SIRT1/p66shc pathway and apoptosis. Collectively, our results support a link between liver cell apoptosis and the miR-34a/SIRT1/p66shc pathway, which can be modulated by CA in NAFLD.

MicroRNAs expression in normal and malignant colon tissues as biomarkers of colorectal cancer and in response to pomegranate extracts consumption: Critical issues to discern between modulatory effects and potential artefacts

SCOPE

MicroRNAs (miRs) are proposed as colorectal cancer (CRC) biomarkers. Pomegranate ellagic acid and their microbiota metabolites urolithins exert anticancer effects in preclinical CRC models, and target normal and malignant colon tissues in CRC patients. Herein, we investigated whether the intake of pomegranate extract (PE) modified miRs expression in surgical colon tissues versus biopsies from CRC patients.

METHODS AND RESULTS

We conducted a randomized, double-blind, controlled trial. Thirty-five CRC patients consumed 900 mg PE daily before surgery. Control CRC patients (no PE intake, n = 10) were included. Our results revealed: (1) significant differences for specific miRs between malignant and normal tissues modifiable by the surgical protocols; (2) opposed trends between -5p and -3p isomolecules; (3) general induction of miRs attributable to the surgery; (4) moderate modulation of various miRs following the PE intake, and (5) no association between tissue urolithins and the observed miRs changes.

CONCLUSION

PE consumption appears to affect specific colon tissue miRs but surgery critically alters miRs levels hindering the discrimination of significant changes caused by dietary factors and the establishment of genuine differences between malignant and normal tissues as biomarkers. The components responsible for the PE effects and the clinical relevance of these observations deserve further research.

Exploring new ways of regulation by resveratrol involving miRNAs, with emphasis on inflammation

This review presents recent evidence implicating microRNAs (miRNAs) in the beneficial effects of resveratrol (trihydroxystilbene), a nonflavonoid plant polyphenol, with emphasis on its anti-inflammatory effects. Many diseases and pathologies have been linked, directly or indirectly, to inflammation. These include infections, injuries, atherosclerosis, diabetes mellitus, obesity, cancer, osteoarthritis, age-related macular degeneration, demyelination, and neurodegenerative diseases. Resveratrol can both decrease the secretion of proinflammatory cytokines (e.g., IL-6, IL-8, and TNF-α) and increase the production of anti-inflammatory cytokines; it also decreases the expression of adhesion proteins (e.g., ICAM-1) and leukocyte chemoattractants (e.g., MCP-1). Resveratrol's primary targets appear to be the transcription factors AP-1 and NF-κB, as well as the gene COX2. Although no mechanistic link between any particular miRNA and resveratrol has been identified, resveratrol effects depend at least in part upon the modification of the expression of a variety of miRNAs that can be anti-inflammatory (e.g., miR-663), proinflammatory (e.g., miR-155), tumor suppressing (e.g., miR-663), or oncogenic (e.g., miR-21).

New perspectives on bioactivity of olive oil: evidence from animal models, human interventions and the use of urinary proteomic biomarkers

Olive oil (OO) is the primary source of fat in the Mediterranean diet and has been associated with longevity and a lower incidence of chronic diseases, particularly CHD. Cardioprotective effects of OO consumption have been widely related with improved lipoprotein profile, endothelial function and inflammation, linked to health claims of oleic acid and phenolic content of OO. With CVD being a leading cause of death worldwide, a review of the potential mechanisms underpinning the impact of OO in the prevention of disease is warranted. The current body of evidence relies on mechanistic studies involving animal and cell-based models, epidemiological studies of OO intake and risk factor, small- and large-scale human interventions, and the emerging use of novel biomarker techniques associated with disease risk. Although model systems are important for mechanistic research nutrition, methodologies and experimental designs with strong translational value are still lacking. The present review critically appraises the available evidence to date, with particular focus on emerging novel biomarkers for disease risk assessment. New perspectives on OO research are outlined, especially those with scope to clarify key mechanisms by which OO consumption exerts health benefits. The use of urinary proteomic biomarkers, as highly specific disease biomarkers, is highlighted towards a higher translational approach involving OO in nutritional recommendations.

Urinary Excretion of Select Dietary Polyphenol Metabolites Is Associated with a Lower Risk of Type 2 Diabetes in Proximate but Not Remote Follow-Up in a Prospective Investigation in 2 Cohorts of US Women

BACKGROUND

Polyphenols are phytochemicals that possess antioxidant and anti-inflammatory properties and improve glucose metabolism in animal experiments, although data from prospective epidemiologic studies examining polyphenol intakes in relation to type 2 diabetes (T2D) risk are inconsistent.

OBJECTIVES

We examined urinary excretion of select flavonoid and phenolic acid metabolites, as biomarkers of intake, in relation to T2D risk.

METHODS

Eight polyphenol metabolites (naringenin, hesperetin, quercetin, isorhamnetin, catechin, epicatechin, caffeic acid, and ferulic acid) were quantified in spot urine samples by liquid chromatography/mass spectrometry among 1111 T2D case-control pairs selected from the Nurses' Health Study (NHS) and NHSII.

RESULTS

Higher urinary excretion of hesperetin was associated with a lower T2D risk after multivariate adjustment: the OR comparing top vs. bottom quartiles was 0.68 (95% CI: 0.49, 0.96), although a linear trend was lacking (P = 0.30). The other measured polyphenols were not significantly associated with T2D risk after multivariate adjustment. However, during the early follow-up period [≤ 4.6 y (median) since urine sample collection], markers of flavanone intakes (naringenin and hesperetin) and flavonol intakes (quercetin and isorhamnetin) were significantly associated with a lower T2D risk. The ORs (95% CIs) comparing extreme quartiles were 0.61 (0.39, 0.98; P-trend: 0.03) for total flavanones and 0.55 (0.33, 0.92; P-trend: 0.04) for total flavonols (P-interaction with follow-up length: ≤ 0.04). An inverse association was also observed for caffeic acid during early follow-up only: the OR was 0.52 (95% CI: 0.32, 0.84; P-trend: 0.03). None of these markers was associated with T2D risk during later follow-up. Metabolites of flavan-3-ols and ferulic acid were not associated with T2D risk in either period.

CONCLUSIONS

These results suggest that specific flavonoid subclasses, including flavanones and flavonols, as well as caffeic acid, are associated with a lower T2D risk in relatively short-term follow-up but not during longer follow-up. Substantial within-person variability of the metabolites in single spot urine samples may limit the ability to capture associations with long-term disease risk.

Dietary apigenin reduces LPS-induced expression of miR-155 restoring immune balance during inflammation

SCOPE

High incidence of inflammatory diseases afflicts the increasing aging-population infringing a great health burden. Dietary flavonoids, including the flavone apigenin, are emerging as important anti-inflammatory nutraceuticals due to their health benefits, lack of adverse effects and reduced costs. MicroRNAs (miRs) play a central role in inflammation by regulating gene expression, yet how dietary ingredients affect miRs is poorly understood. The aim of this study was to identify miRs involved in the anti-inflammatory activity of apigenin and apigenin-rich diets and determine their immune regulatory mechanisms in macrophages and in vivo.

METHODS AND RESULTS

A high-throughput quantitative reverse transcriptase PCR screen of 312 miRs in macrophages revealed that apigenin reduced LPS-induced miR-155 expression. Analyses of miR-155 precursor and primary transcript indicated that apigenin regulated miR-155 transcriptionally. Apigenin-reduced expression of miR-155 led to the increase of anti-inflammatory regulators forkhead box O3a and smooth-muscle-actin and MAD-related protein 2 in LPS-treated macrophages. In vivo, apigenin or a celery-based apigenin-rich diet reduced LPS-induced expression of miR-155 and decreased tumor necrosis factor α in lungs from LPS-treated mice.

CONCLUSION

These results demonstrate that apigenin and apigenin-rich diets exert effective anti-inflammatory activity in vivo by reducing LPS-induced expression of miR-155, thereby restoring immune balance.

Potential role of olive oil phenolic compounds in the prevention of neurodegenerative diseases

Adherence to the Mediterranean Diet (MD) has been associated with a reduced incidence of neurodegenerative diseases and better cognitive performance. Virgin olive oil, the main source of lipids in the MD, is rich in minor phenolic components, particularly hydroxytyrosol (HT). HT potent antioxidant and anti-inflammatory actions have attracted researchers' attention and may contribute to neuroprotective effects credited to MD. In this review HT bioavailability and pharmacokinetics are presented prior to discussing health beneficial effects. In vitro and in vivo neuroprotective effects together with its multiple mechanisms of action are reviewed. Other microconstituents of olive oil are also considered due to their potential neuroprotective effects (oleocanthal, triterpenic acids). Finally, we discuss the potential role of HT as a therapeutic tool in the prevention of neurodegenerative diseases.

Antioxidant and anti-inflammatory properties of an aqueous cyanophyta extract derived from Arthrospira platensis: contribution to bioactivities by the non-phycocyanin aqueous fraction

The goal for this work was to characterize basic biological properties of a novel Arthrospira platensis-based aqueous cyanophyta extract (ACE), enriched in the known anti-inflammatory cyclooxygenase-2 (COX-2) inhibitor phycocyanin (PC), but also containing a high level of non-PC bioactive compounds. Antioxidant properties were tested in parallel in the Folin–Ciocalteu assay (chemical antioxidant capacity) and in the cellular antioxidant protection (CAP-e) bioassay, where both the PC and the non-PC fractions contributed to the antioxidant capacity and CAP of ACE. In contrast to the COX-2 inhibition seen in the presence of PC, the inhibition of enzymatic activity of the inflammatory mediator Lipoxygenase was associated specifically with the non-PC fraction of ACE. Inhibition of formation of reactive oxygen species (ROS) was evaluated using polymorphonuclear cells from healthy human donors. The inhibition of ROS formation was seen for both the PC and non-PC fractions, with ACE showing the most robust effect. The effects of PC, non-PC, and ACE on clotting and clot lysing was tested using a modified Euglobulin fibrinolytic assay in vitro. In the presence of PC, non-PC, and ACE, the time for clot formation and lysis was not affected; however, the clots were significantly more robust. This effect was statistically significant (p<.05) at doses between 125–500 μg/mL, and returned to baseline at lower doses. Both PC and the non-PC fraction contributed to the antioxidant properties and anti-inflammatory effects, without a negative impact on blood clotting in vitro. This suggests a potential benefit for the consumable ACE extract in assisting the reduction of inflammatory conditions.

Membrane steroid receptor-mediated action of soy isoflavones: tip of the iceberg

Soy isoflavone's (genistein and daidzein in particular) biological significance has been thoroughly studied for decades, so we started from the premise that refreshed investigation approach in this field should consider identification of their new molecular targets. In addition to recently described epigenetic aspects of polyphenole action, the cell membrane constituents-mediated effects of soy isoflavones are worthy of special attention. Accordingly, the expanding concept of membrane steroid receptors and rapid signaling from the cell surface may include the prominent role of these steroid-like compounds. It was observed that daidzein strongly interacts with membrane estrogen receptors in adrenal medullary cells. At low doses, daidzein was found to stimulate catecholamine synthesis through extracellular signal-regulated kinase 1/2 or protein kinase A pathways, but at high doses, it inhibited catecholamine synthesis and secretion induced by acetylcholine. Keeping in mind that catecholamine excess can contribute to the cardiovascular pathologies and that catecholamine lack may lead to depression, daidzein application promises to have a wide range of therapeutic effects. On the other hand, it was shown in vitro that genistein inhibits LNCaP prostate cancer cells invasiveness by decreasing the membrane fluidity along with immobilization of the androgen receptor containing membrane lipid rafts, with down regulation of the androgen receptors and Akt signaling. These data are promising in development of the molecular pharmacotherapy pertinent to balanced soy isoflavone treatment of cardiovascular, psychiatric, and steroid-related malignant diseases.

Manipulating miRNA Expression: A Novel Approach for Colon Cancer Prevention and Chemotherapy

Small non-coding RNA has been implicated in the control of various cellular processes such as proliferation, apoptosis, and differentiation. About 50% of the miRNA genes are positioned in cancer-associated genomic regions. Several studies have shown that miRNA expression is deregulated in cancer and modulating their expression has reversed the cancer phenotype. Therefore, mechanisms to modulate microRNA (miRNA) activity have provided a novel opportunity for cancer prevention and therapy. In addition, a common cause for development of colorectal cancers is environmental and lifestyle factors. One such factor, diet has been shown to modulate miRNA expression in colorectal cancer patients. In this chapter, we will summarize the work demonstrating that miRNAs are novel promising drug targets for cancer chemoprevention and therapy. Improved delivery, increased stability and enhanced regulation of off-target effects will overcome the current challenges of this exciting approach in the field of cancer prevention and therapy.

Arctigenin in combination with quercetin synergistically enhances the antiproliferative effect in prostate cancer cells

SCOPE

We investigated whether a combination of two promising chemopreventive agents arctigenin (Arc) and quercetin (Q) increases the anticarcinogenic potency at lower concentrations than necessary when used individually in prostate cancer.

METHODS AND RESULTS

Androgen-dependent LAPC-4 and LNCaP prostate cancer cells were treated with low doses of Arc and Q alone or in combination for 48 h. The antiproliferative activity of Arc was 10- to 20-fold stronger than Q in both cell lines. Their combination synergistically enhanced the antiproliferative effect, with a stronger effect in androgen receptor (AR) wild-type LAPC-4 cells than in AR mutated LNCaP cells. Arc demonstrated a strong ability to inhibit AR protein expression in LAPC-4 cells. The combination treatment significantly inhibited both AR and PI3K/Akt pathways compared to control. A protein array analysis revealed that the mixture targets multiple pathways particularly in LAPC-4 cells including Stat3 pathway. The mixture significantly inhibited the expression of several oncogenic microRNAs including miR-21, miR-19b, and miR-148a compared to control. The mixture also enhanced the inhibition of cell migration in both cell lines compared to individual compounds tested.

CONCLUSION

The combination of Arc and Q that target similar pathways, at low physiological doses, provides a novel regimen with enhanced chemoprevention in prostate cancer.

Epigenetic nutraceutical diets in Alzheimer's disease

There is growing support that environmental influences and individual genetic susceptibility may increase the incidence and accelerate the onset of Alzheimer's disease (AD). Epigenetic mechanisms encompass a complex regulatory network of modifications with considerable impact on health and disease risk. Abnormal epigenetic regulation is a hallmark in many pathological conditions including AD. It is well recognized that numerous bioactive dietary components mediate epigenetic modifications associated with the pathophysiology of several diseases. Although the influences of dietary factors on epigenetic regulation have been extensively investigated, only few studies have explored the effects of specific food components in regulating epigenetic patterns during neurodegeneration and AD. Epigenetic nutritional research has substantial potential for AD and may represent a window of opportunity to complement other interventions. Here, we provide a brief overview of the main mechanisms involved in AD, some of which may be epigenetically modulated by bioactive food.

Beneficial effects of proanthocyanidins in the cardiac alterations induced by aldosterone in rat heart through mineralocorticoid receptor blockade

Aldosterone administration in rats results in several cardiac alterations. Previous studies have demonstrated that proanthocyanidins, phenolic bioactive compounds, have cardioprotective effects. We studied the potential beneficial effects of the proanthocyanidin-rich almond skin extract (PASE) on the cardiac alterations induced by aldosterone-salt treatment, their effects in mineralocorticoid receptor activity and we sought to confirm proanthocyanidins as the specific component of the extract involved in the beneficial cardiac effects. Male Wistar rats received aldosterone (1 mg/Kg/day) +1% NaCl for 3 weeks. Half of the animals in each group were simultaneously treated with either PASE (100 mg/Kg/day) or spironolactone (200 mg/Kg/day). The ability of PASE to act as an antagonist of the mineralocorticoid receptor was examined using a transactivation assay. High performance liquid chromatography was used to identify and to isolate proanthocyanidins. Hypertension and diastolic dysfunction induced by aldosterone were abolished by treatment with PASE. Expression of the aldosterone mediator SGK-1, together with fibrotic, inflammatory and oxidative mediators were increased by aldosterone-salt treatment; these were reduced by PASE. Aldosterone-salt induced transcriptional activity of the mineralocorticoid receptor was reduced by PASE. HPLC confirmed proanthocyanidins as the compound responsible for the beneficial effects of PASE. The effects of PASE were comparable to those seen with the mineralocorticoid antagonist, spironolactone. The observed responses in the aldosterone-salt treated rats together with the antagonism of transactivation at the mineralocorticoid receptor by PASE provides evidence that the beneficial effect of this proanthocyanidin-rich almond skin extract is via as a mineralocorticoid receptor antagonist with proanthocyanidins identified as the compounds responsible for the beneficial effects of PASE.

The antioxidant activity of soursop decreases the expression of a member of the NADPH oxidase family

Cellular oxidative stress produced by an increase in free radicals is one of the factors that promote the development of chronic degenerative diseases; therefore, consuming natural antioxidants helps minimize their negative effects. This study evaluated the cytotoxicity of the soursop extract (Annona muricata), its cytoprotective capacity against oxidative stress induced by hydrogen peroxide, the inhibitory potential of reactive oxygen species (ROS), the molecular mechanism of its antioxidant action, and its capacity to repair cellular damage in the fibroblast cell line. The soursop extract proved not to be cytotoxic in fibroblast cultures and showed cytoprotective capacity against hydrogen peroxide-induced stress; in cell culture it reduced the generation of ROS significantly by inhibiting a sub-unit of the NADPH oxidase enzyme (p47phox). The soursop extract can prevent damage caused by cellular oxidants.

Role of microRNAs in the age-related changes in skeletal muscle and diet or exercise interventions to promote healthy aging in humans

Progressive age-related changes in skeletal muscle mass and composition, underpin decreases in muscle function, which can inturn lead to impaired mobility and quality of life in older adults. MicroRNAs (miRNAs) are important post-transcriptional regulators of gene expression in skeletal muscle and are associated with aging. Accumulating evidence suggests that miRNAs play an important role in the age-related changes in skeletal muscle mass, composition and function. At the cellular level, miRNAs have been demonstrated to regulate muscle cell proliferation and differentiation. Furthermore, miRNAs are involved in the transitioning of muscle stem cells from a quiescent, to either an activated or senescence state. Evidence from animal and human studies has shown miRNAs are modulated in muscle atrophy and hypertrophy. In addition, miRNAs have been implicated in changes in muscle fiber composition, fat infiltration and insulin resistance. Both exercise and dietary interventions can combat age-related changes in muscle mass, composition and function, which may be mediated by miRNA modulation in skeletal muscle. Circulating miRNA species derived from myogenic cell populations represent potential biomarkers of aging muscle and the molecular responses to exercise or diet interventions, but larger validation studies are required. In future therapeutic approaches targeting miRNAs, either through exercise, diet or drugs may be able to slow down or prevent the age-related changes in skeletal muscle mass, composition, function, hence help maintain mobility and quality of life in old age.

Dietary flavanols modulate the transcription of genes associated with cardiovascular pathology without changes in their DNA methylation state

Background

In a recent intervention study, the daily supplementation with 200 mg monomeric and oligomeric flavanols (MOF) from grape seeds for 8 weeks revealed a vascular health benefit in male smokers. The objective of the present study was to determine the impact of MOF consumption on the gene expression profile of leukocytes and to assess changes in DNA methylation.

Methodology/Principal Findings

Gene expression profiles were determined using whole genome microarrays (Agilent) and DNA methylation was assessed using HumanMethylation450 BeadChips (Illumina). MOF significantly modulated the expression of 864 genes. The majority of the affected genes are involved in chemotaxis, cell adhesion, cell infiltration or cytoskeleton organisation, suggesting lower immune cell adhesion to endothelial cells. This was corroborated by in vitro experiments showing that MOF exposure of monocytes attenuates their adhesion to TNF-α-stimulated endothelial cells. Nuclear factor kappa B (NF-κB) reporter gene assays confirmed that MOF decrease the activity of NF-κB. Strong inter-individual variability in the leukocytes' DNA methylation was observed. As a consequence, on group level, changes due to MOF supplementation could not be found.

Conclusion

Our study revealed that an 8 week daily supplementation with 200 mg MOF modulates the expression of genes associated with cardiovascular disease pathways without major changes of their DNA methylation state. However, strong inter-individual variation in leukocyte DNA methylation may obscure the subtle epigenetic response to dietary flavanols. Despite the lack of significant changes in DNA methylation, the modulation of gene expression appears to contribute to the observed vascular health effect of MOF in humans.

Nutritional aspects of metabolic inflammation in relation to health--insights from transcriptomic biomarkers in PBMC of fatty acids and polyphenols

Recent research has highlighted potential important interaction between metabolism and inflammation, within the context of metabolic health and nutrition, with a view to preventing diet-related disease. In addition to this, there is a paucity of evidence in relation to accurate biomarkers that are capable of reflecting this important biological interplay or relationship between metabolism and inflammation, particularly in relation to diet and health. Therefore the objective of this review is to highlight the potential role of transcriptomic approaches as a tool to capture the mechanistic basis of metabolic inflammation. Within this context, this review has focused on the potential of peripheral blood mononuclear cells transcriptomic biomarkers, because they are an accessible tissue that may reflect metabolism and subacute chronic inflammation. Also these pathways are often dysregulated in the common diet-related diseases obesity, type 2 diabetes, and cardiovascular disease, thus may be used as markers of systemic health. The review focuses on fatty acids and polyphenols, two classes of nutrients/nonnutrient food components that modulate metabolism/inflammation, which we have used as an example of a proof-of-concept with a view to understanding the extent to which transcriptomic biomarkers are related to nutritional status and/or sensitive to dietary interventions. We show that both nutritional components modulate inflammatory markers at the transcriptomic level with the capability of profiling pro- and anti-inflammatory mechanisms in a bidirectional fashion; to this end transcriptomic biomarkers may have potential within the context of metabolic inflammation. This transcriptomic biomarker approach may be a sensitive indicator of nutritional status and metabolic health.