Pioglitazone ameliorates high fat diet-induced hypertension and induces catechol o-methyl transferase expression in rats.

Our study aimed to investigate the effect of pioglitazone (PIO) on the obesity-associated metabolic effects and whether this effect is associated with modulation of catechol O-methyl transferase (COMT) expression in the high fat diet (HFD) induced obese rats. Male Wistar rats fed HFD were used to evaluate the effect of PIO on obesity-associated hypertension and the expression of COMT. The HFD-induced obesity was confirmed by the change in body weights, the fasting serum insulin (FSI) which assessed by ELISA, homeostasis model assessment - insulin resistance (HOMA-IR), fasting blood glucose (FBG), oral glucose tolerance test (OGTT) and lipid profile which were determined by colorimetric methods. Plasma epinephrine (EP) and norepinephrine (NE) were determined by ELISA and the systolic blood pressure (SBP) was recorded using the tail-cuff method. COMT expression was assessed by quantitative real time-polymerase chain reaction (qRT-PCR), and western blotting. The HFD-induced obesity was associated with glucose intolerance, derangement of the lipid profile, increased SBP, reduced COMT expression with a concomitant increase in plasma catecholamines. Most importantly, treatment with PIO ameliorated the HFD-induced metabolic changes, improved the lipid profile, reduced SBP, increased COMT expression, and reduced plasma catecholamines. Treatment with PIO reversed HFD-induced glucose intolerance and the associated metabolic derangement. In addition, these effects of PIO were associated with up-regulating COMT expression with a subsequent reduction in plasma catecholamines levels.

Novel Insight into Differential Gene Expression and Clinical Significance of Dopamine Receptors, COMT, and IL6 in BPH and Prostate Cancer.

BACKGROUND: Benign prostatic hyperplasia (BPH) and prostate cancer (PCa) are the most prevalent diseases in male population, implicated with fundamental differences between benign and malignant growth of prostate cells. An imbalance through a network of nervous, endocrine, and immune systems initiate a signal of altered growth from the brain to the prostate gland, leading to adverse effects such as inflammation. OBJECTIVE: The aim of this study was to evaluate the gene expression of dopamine receptor family, COMT, and IL6 to identify novel correlations in BPH and PCa in both blood and tumor of the patients. METHODS: Peripheral blood mononuclear cells from BPH (n= 30) and PCa (n= 30) patients, and prostate tumor tissues (n= 14) along with pathologically normal adjacent tissues (n= 14) were isolated, mRNA was extracted, and cDNA was synthesized, respectively. Quantitative real- time PCR was applied for DRD1- DRD5, COMT, and IL6 genes in all samples. RESULTS: We found, for the first time, that the expression of COMT and IL6 genes were inversely correlated with the expression of DRD1 and DRD2 genes through the extent of differentiation of PCa from BPH condition. In addition, the PSA levels were correlated with the expression of DRD1 in BPH cases and DRD1, DRD4, DRD5, and IL6 in PCa cases. CONCLUSION: Results implicate a potential cross- talk between the signaling pathways derived by IL6 cytokine and dopamine receptors in PCa. Thus, it seems promising to reassemble the consequent signaling pathways by adequate agonists and antagonists to help increase therapeutic efficacy.

Fingolimod interrupts the cross talk between estrogen metabolism and sphingolipid metabolism within prostate cancer cells.

Sphingolipids are critical regulators of tumor microenvironments and play an important role in estrogen-dependent cancers. Estrogen and estrogen metabolites were found to be involved in prostate cancer. Fingolimod (FTY720) is a sphingokinase-1 (SphK1) inhibitor with anticancer properties against various tumor cell types. Herein, we investigated the interference of FTY720 with the cross talk between sphingolipid metabolism and estrogen metabolism within prostate cancer cells. FTY720 showed cytotoxic antiproliferative effects against androgen-dependent and -independent prostate cancer cells with IC50 ranging from 3.0 ±â€¯0.3 to 6.8 ±â€¯1.7 µM. Exposure of prostate cancer cells to FTY720 resulted in a dramatic decrease in the concentration of estradiol, estrone, 4-hydroxyestradiol and 16α-hydroxyestrone compared to control cells. However, FTY720 significantly increased the concentration of 2-methoxyestrone and 2-methoxyestradiol within prostate cancer cells. This was mirrored by significant downregulating of the expression of estrogen and catechol estrogen-synthesizing enzymes (CYP19, CYP1A1 and CYP1B1) within prostate cancer cells. On the other hand, FTY720 significantly upregulated the expression of catechol estrogen-detoxifying enzyme (COMT). Additionally, FTY720 abolished estrogen-stimulated expression of ERα and basal expression of ERß within prostate cancer cells. Furthermore, FTY720 suppressed the expression of the ER-downstream regulated genes, CXCR4 and cyclin D1. Reciprocally, it was found that estradiol and catechol estrogens significantly induced the expression of SphK1 while methoxylated catechol estrogen suppressed its expression within prostate cancer cells in a dose-dependent manner. Current research has highlighted the hazardous influence of the estrogenic component to prostate cancer. We found that fingolimod (FTY720) could modulate the estrogenic micromilieu and interrupt its cross talk with sphingolipid metabolism.

Differential COMT expression and behavioral effects of COMT inhibition in male and female Wistar and alcohol preferring rats.

Polymorphisms of the catechol-O-methyl transferase (COMT) gene have been associated with alcoholism, suggesting that alterations in the metabolism of catecholamines may be a critical component of the neuropathology of alcoholism. In the current experiments, the COMT inhibitor tolcapone was utilized in an operant behavioral model of reinforcer-seeking and drinking to determine if this compound was capable of remediating the excessive seeking and drinking phenotype of the alcohol-preferring P rat. Tolcapone was administered to male and female alcohol-reinforced P and Wistar rats. Additionally, tolcapone was administered to male sucrose-reinforced P and Wistar rats to determine if its effects also extended to a natural reinforcer. Animals were trained to make an operant response that resulted in 20 min uninterrupted access to the reinforcer solutions. Tolcapone had no effect in female rats on either seeking or consumption of ethanol. However, reductions of both reinforcer seeking and consumption were observed in male P rats, but only of seeking in Wistars. In separate experiments, using reinforcer naïve male and female animals, COMT expression was assessed via Western Blot analysis. Sex differences in COMT expression were also observed, where male P rats exhibited a marked reduction in protein expression relative to females in the PFC. Sex differences were not observed for Wistars or in the striatum and hippocampus. These data complement our previous findings in which tolcapone reduced cue-evoked responses in P rats and further suggest clinical utility of COMT inhibitors in the treatment of addiction disorders, specifically in male high drinkers.

Effects of central fibroblast growth factor 21 and irisin in anxiety-like behavior.

Adipose tissue and skeletal muscle are organs capable of secreting many bioactive molecules, such as adipomiokines that could be possibly involved in mood disorders. In the present work, we investigated the possible behavioral effects of a single intracerebroventricular (i.c.v.) injection of two adipomiokines, fibrobroblast growth factor (FGF)-21 (0.5-5.0 µg) and irisin (0.4-0.6 µg), in male rats tested in the open field and elevated plus maze tests. Prefrontal cortex levels of norepinephrine (NE), dopamine (DA) and serotonin (5-hydroxytryptamine, 5-HT) and the gene expression of catechol-O-methyltransferase (COMT), dopamine transport (DAT) and tyrosine hydroxylase (TH), were measured by high performance liquid chromatography (HPLC) analysis and real-time reverse transcription polymerase chain reaction (RT-PCR). Both FGF-21 and irisin administration induced anxiogenic behavior, increased DA levels in prefrontal cortex, decreased COMT, DAT and increased TH gene expression. In conclusion, in the present study we demonstrated behavioral effects induced by central FGF-21 and irisin injections that could involve increased DA signaling in the prefrontal cortex.

Disturbed testicular expression of the estrogen-metabolizing enzymes CYP1A1 and COMT in infertile men with primary spermatogenic failure: possible negative implications on Sertoli cells.

Estradiol (E2 ) is normally metabolized to hydroxyestradiols and methoxyestradiols by CYP1A1, CYP1B1 and COMT. However, an altered production of these metabolites by a disturbed expression of these enzymes is associated with reproductive and non-reproductive pathologies. In vitro studies suggest that increased hydroxyestradiols and methoxyestradiols intratesticular generation is related to male infertility, but no studies have explored whether infertile men have a disturbed testicular expression of the enzymes that generate these E2 metabolites. The aim of this study was to assess CYP1A1, CYP1B1 and COMT testicular expression at mRNA and protein level in men with spermatogenic impairment. Seventeen men with primary spermatogenic failure (13 with Sertoli cell-only syndrome and four with maturation arrest) and nine controls with normal spermatogenesis were subjected to testicular biopsy. mRNA was quantified using real-time RT-PCR and protein expression was evaluated using western blot and immunohistochemistry followed by integrated optic density analysis. Besides, the effects of hydroxyestradiols and methoxyestradiols on testosterone-induced transcriptional activity were evaluated in TM4 cells using a luciferase reporter assay system. Our results show that patients with Sertoli cell-only syndrome had significantly elevated COMT expression at the mRNA level, higher COMT immunoreactivity in their seminiferous tubules and increased protein expression of the soluble COMT isoform (S-COMT), whereas patients with maturation arrest had significantly elevated CYP1A1 mRNA levels and higher CYP1A1 immunoreactivity in interstitial space. Finally, 2-hydroxyestradiol decreased testosterone-induced transcriptional activity in Sertoli cells in vitro. In conclusion, male infertility is related to disturbed testicular expression of the enzymes responsible for producing hydroxyestradiols and/or methoxyestradiols. If these changes are related with increased intratesticular hydroxyestradiols and methoxyestradiols concentrations, they could elicit an impaired Sertoli cell function. Our results suggest CYP1A1 and COMT as new potential targets in treating male infertility.

Catechins Variously Affect Activities of Conjugation Enzymes in Proliferating and Differentiated Caco-2 Cells.

The knowledge of processes in intestinal cells is essential, as most xenobiotics come into contact with the small intestine first. Caco-2 cells are human colorectal adenocarcinoma that once differentiated, exhibit enterocyte-like characteristics. Our study compares activities and expressions of important conjugation enzymes and their modulation by green tea extract (GTE) and epigallocatechin gallate (EGCG) using both proliferating (P) and differentiated (D) caco-2 cells. The mRNA levels of the main conjugation enzymes were significantly elevated after the differentiation of Caco-2 cells. However, no increase in conjugation enzymes' activities in differentiated cells was detected in comparison to proliferating ones. GTE/EGCG treatment did not affect the mRNA levels of any of the conjugation enzymes tested in either type of cells. Concerning conjugation enzymes activities, GTE/EGCG treatment elevated glutathione S-transferase (GST) activity by approx. 30% and inhibited catechol-O-methyltransferase (COMT) activity by approx. 20% in differentiated cells. On the other hand, GTE as well as EGCG treatment did not significantly affect the activities of conjugation enzymes in proliferating cells. Administration of GTE/EGCG mediated only mild changes of GST and COMT activities in enterocyte-like cells, indicating a low risk of GTE/EGCG interactions with concomitantly administered drugs. However, a considerable chemo-protective effect of GTE via the pronounced induction of detoxifying enzymes cannot be expected as well.

Melatonin mediated antidepressant-like effect in the hippocampus of chronic stress-induced depression rats: Regulating vesicular monoamine transporter 2 and monoamine oxidase A levels.

The hippocampus is sensitive to stress which activates norepinephrine terminals deriving from the locus coeruleus. Melatonin exerts positive effects on the hippocampal neurogenic process and on depressive-like behaviour. Thus, in the present study, an examination was made of the effect of chronic melatonin treatment on norepinephrine content, synthesis, uptake, vesicular transport and degradation in the hippocampus of rats exposed to CUMS. This entailed quantifying the norephinephrine, mRNA and protein levels of DBH, NET, VMAT 2, MAO-A and COMT. The results show that CUMS evoked prolonged immobility. Melatonin treatment decreased immobility in comparison with the placebo group, reflecting an antidepressant-like effect. Compared with the placebo group, a dramatic decrease in norepinephrine content, decreased VMAT2 mRNA and protein and increased MAO-A protein levels in the hippocampus of the CUMS rats were observed. However, no significant differences in the levels of DBH, NET, COMT mRNA and protein and MAO-A mRNA levels between the placebo and the stressed groups were found. The results showed the restorative effects of melatonin on the stress-induced decline in the norepinephrine content of the hippocampus. It was observed that melatonin treatment in the CUMS rats prevented the stress-induced decrease in VMAT2 mRNA and protein levels, whereas it reduced the increase of the mRNA of COMT and protein levels of MAO-A. Chronic treatment with melatonin failed to alter the gene expression of DBH or NET in the hippocampus of the CUMS rats. Additionally, the results show that melatonin enhances VMAT2 expression and norepinephrine storage, whilst it reduces norepinephrine degrading enzymes.

Revealing ecological risks of priority endocrine disrupting chemicals in four marine protected areas in Hong Kong through an integrative approach.

Marine Protected Areas (MPAs) in Hong Kong are situated in close proximity to urbanized areas, and inevitably influenced by wastewater discharges and antifouling biocides leached from vessels. Hence, marine organisms inhabiting these MPAs are probably at risk. Here an integrative approach was employed to comprehensively assess ecological risks of eight priority endocrine disrupting chemicals (EDCs) in four MPAs of Hong Kong. We quantified their concentrations in environmental and biota samples collected in different seasons during 2013-2014, while mussels (Septifer virgatus) and semi-permeable membrane devices were deployed to determine the extent of accumulation of the EDCs. Extracts from the environmental samples were subjected to the yeast estrogen screen and a novel human cell-based catechol-O-methyltransferase ELISA to evaluate their estrogenic activities. The results indicated ecological risks of EDCs in the Cape d'Aguilar Marine Reserve. This integrated approach can effectively evaluate ecological risks of EDCs through linking their concentrations to biological effects.

[Expression of Catechol-O-Methyltransferase (Comt), Mineralocorticoid Receptor (Mlr), and Epithelial Sodium Channel (ENaC) Genes in Kidneys of Hypertensive ISIAH Rats at Rest and during Response to Stress].

Emotional stress plays a significant role in the processes of the development of arterial hypertension, especially in the presence of genetic predisposition. The origin and maintenance of hypertensive status during stress development can be activated by the sympathetic nervous system. An increase in sympathetic stimulation can, in turn, result in a change in the functions of kidneys, which provide fluid and electrolyte balance of the organism. A comparative study of the mRNA expression level of catechol-o-methyltransferase (Comt), mineralocorticoid receptor (Mlr), and ß-subunit of epithelial sodium channel (ß-ENaC) genes was conducted on the kidneys of hypertensive ISIAH rats and normotensive WAG rats at rest and after the effect of emotional stress. The discovered changes in the expression level of the selected genes confirm their involvement in increased sympathetic stimulation of the kidney, along with changes in the function of kidney regulation of fluid and electrolyte balance, which is an important factor of the development of sustained hypertension in the ISIAH rats strain.

An artificial neural network for membrane-bound catechol-O-methyltransferase biosynthesis with Pichia pastoris methanol-induced cultures.

BACKGROUND: Membrane proteins are important drug targets in many human diseases and gathering structural information regarding these proteins encourages the pharmaceutical industry to develop new molecules using structure-based drug design studies. Specifically, membrane-bound catechol-O-methyltransferase (MBCOMT) is an integral membrane protein that catalyzes the methylation of catechol substrates and has been linked to several diseases such as Parkinson's disease and Schizophrenia. Thereby, improvements in the clinical outcome of the therapy to these diseases may come from structure-based drug design where reaching MBCOMT samples in milligram quantities are crucial for acquiring structural information regarding this target protein. Therefore, the main aim of this work was to optimize the temperature, dimethylsulfoxide (DMSO) concentration and the methanol flow-rate for the biosynthesis of recombinant MBCOMT by Pichia pastoris bioreactor methanol-induced cultures using artificial neural networks (ANN). RESULTS: The optimization trials intended to evaluate MBCOMT expression by P. pastoris bioreactor cultures led to the development of a first standard strategy for MBCOMT bioreactor biosynthesis with a batch growth on glycerol until the dissolved oxygen spike, 3 h of glycerol feeding and 12 h of methanol induction. The ANN modeling of the aforementioned fermentation parameters predicted a maximum MBCOMT specific activity of 384.8 nmol/h/mg of protein at 30°C, 2.9 mL/L/H methanol constant flow-rate and with the addition of 6% (v/v) DMSO with almost 90% of healthy cells at the end of the induction phase. These results allowed an improvement of MBCOMT specific activity of 6.4-fold in comparison to that from the small-scale biosynthesis in baffled shake-flasks. CONCLUSIONS: The ANN model was able to describe the effects of temperature, DMSO concentration and methanol flow-rate on MBCOMT specific activity, as shown by the good fitness between predicted and observed values. This experimental procedure highlights the potential role of chemical chaperones such as DMSO in improving yields of recombinant membrane proteins with a different topology than G-coupled receptors. Finally, the proposed ANN shows that the manipulation of classic fermentation parameters coupled with the addition of specific molecules can open and reinforce new perspectives in the optimization of P. pastoris bioprocesses for membrane proteins biosynthesis.

Differences in 4-hydroxyestradiol levels in leukocytes are related to CYP1A1(∗)2C, CYP1B1(∗)3 and COMT Val158Met allelic variants.

Exposure to estrogen and its metabolites, including catechol estrogens (CEs) and catechol estrogen quinones (CE-Qs) is closely related to breast cancer. Polymorphisms of the genes involved in the catechol estrogens metabolism pathway (CEMP) have been shown to affect the production of CEs and CE-Qs. In this study, we measured the induction of CYP1A1, CYP1B1, COMT, and GSTP1 by 17ß-estradiol (17ß-E2) in leukocytes with CYP1A1(∗)2C, CYP1B1(∗)3, COMT Val158Met and GSTP1 Ile105Val polymorphisms by semi quantitative RT-PCR and compared the values to those of leukocytes with wild type alleles; we also compared the differences in formation of 4- hydroxyestradiol (4-OHE2) and DNA-adducts. The data show that in the leukocytes with mutant alleles treatment with 17ß-E2 up-regulates CYP1A1 and CYP1B1 and down-regulates COMT mRNA levels, resulting in major increments in 4-OHE2 levels compared to leukocytes with wild-type alleles. Therefore, we propose induction levels of gene expression and intracellular 4-OHE2 concentrations associated with allelic variants in response to exposure of 17ß-E2 as a noninvasive biomarker that can help determine the risk of developing non-hereditary breast cancer in women.

Evaluation of Mut(S) and Mut⁺ Pichia pastoris strains for membrane-bound catechol-O-methyltransferase biosynthesis.

Catechol-O-methyltransferase (COMT, EC 2.1.1.6) is an enzyme that catalyzes the methylation of catechol substrates, and while structural and functional studies of its membrane-bound isoform (MBCOMT) are still hampered by low recombinant production, Pichia pastoris has been described as an attractive host for the production of correctly folded and inserted membrane proteins. Hence, in this work, MBCOMT biosynthesis was developed using P. pastoris X33 and KM71H cells in shake flasks containing a semidefined medium with different methanol concentrations. Moreover, after P. pastoris glass beads lysis, biologically and immunologically active hMBCOMT was found mainly in the solubilized membrane fraction whose kinetic parameters were identical to its correspondent native enzyme. In addition, mixed feeds of methanol and glycerol or sorbitol were also employed, and its levels quantified using liquid chromatography coupled to refractive index detection. Overall, for the first time, two P. pastoris strains with opposite phenotypes were applied for MBCOMT biosynthesis under the control of the strongly methanol-inducible alcohol oxidase (AOX) promoter. Moreover, this eukaryotic system seems to be a promising approach to deliver MBCOMT in high quantities from fermentor cultures with a lower cost-benefit due to the cheaper cultivation media coupled with the higher titers tipically achieved in biorreactors, when compared with previously reported mammallian cell cultures.

Catechol-O-methyltransferase inhibits colorectal cancer cell proliferation and invasion.

BACKGROUND AND AIMS: Catechol-O-methyltransferase (COMT) has been reported as an important molecule in various types of cancers. The biological function of COMT in colorectal cancer (CRC) has not yet been fully investigated. METHODS: We constructed a transient transfection of a CRC cell lines to up- and downregulate COMT expression level and tested the proliferative, invasion ability in vitro. We also constructed a stable transduced CRC cell line and conducted tumor-forming capacity experiment in mouse xenograft model in vivo. RESULTS: In vitro experiment showed that COMT inhibited the cell proliferation by regulating p-Akt, PTEN and inhibited G1 to S phase transition by regulating p53, p27, and cyclinD1. COMT inhibited invasion by regulating E-cadherin. In vivo experiment showed decreased tumor growth in COMT overexpressing cell line. CONCLUSIONS: COMT has tumor-suppressive functions for CRC cell lines in vitro and in vivo experiments.

Hyperoxia-induced changes in estradiol metabolism in postnatal airway smooth muscle.

Supplemental oxygen, used to treat hypoxia in preterm and term neonates, increases the risk of neonatal lung diseases, such as bronchopulmonary dysplasia (BPD) and asthma. There is a known sex predilection for BPD, but the underlying mechanisms are not clear. We tested the hypothesis that altered, local estradiol following hyperoxia contributes to pathophysiological changes observed in immature lung. In human fetal airway smooth muscle (fASM) cells exposed to normoxia or hyperoxia, we measured the expression of proteins involved in estrogen metabolism and cell proliferation responses to estradiol. In fASM cells, CYP1a1 expression was increased by hyperoxia, whereas hyperoxia-induced enhancement of cell proliferation was blunted by estradiol. Pharmacological studies indicated that these effects were attributable to upregulation of CYP1a1 and subsequent increased metabolism of estradiol to a downstream intermediate 2-methoxyestradiol. Microarray analysis of mouse lung exposed to 14 days of hyperoxia showed the most significant alteration in CYP1a1 expression, with minimal changes in expression of five other genes related to estrogen receptors, synthesis, and metabolism. Our novel results on estradiol metabolism in fetal and early postnatal lung in the context of hyperoxia indicate CYP1a1 as a potential mechanism for the protective effect of estradiol in hyperoxia-exposed immature lung, which may help explain the sex difference in neonatal lung diseases.

Interdisciplinarity and nursing research: opportunities and challenges / Interdisciplinaridade e pesquisa em enfermagem: oportunidades e desafios / La interdisciplinariedad y la investigación en enfermería: oportunidades y desafíos

Interdisciplinary collaboration is widely recognized and considered essential for optimizing the development of knowledge and practice. However, interdisciplinarity is commonly accepted as an unquestioned good; rarely examined as both a source of benefit as well as difficulty for nursing and other disciplines. The aim of this article is to critically examine the opportunities and challenges that interdisciplinarity can provide for research in nursing and other disciplines. Based on a North American perspective, I describe the emergence of uni-disciplinary nursing research and the knowledge exchanges that occurred between nursing and other disciplines. I discuss the rise of interdisciplinary research, outline several examples of nursing participation in interdisciplinarity, and highlight the prominent benefits and difficulties associated with interdisciplinary research. I argue that authentic collaboration is required to conduct meaningful interdisciplinary research and describe how this can be promoted.

Colaboração interdisciplinar é amplamente reconhecida e considerada essencial para a otimização do desenvolvimento do conhecimento e prática. No entanto, a interdisciplinaridade é comumente aceita como um bem inquestionável, raramente examinado tanto como uma fonte de benefícios, bem como dificuldade para a enfermagem e outras disciplinas. O objetivo deste artigo é analisar criticamente as oportunidades e desafios que a interdisciplinaridade pode oferecer para a pesquisa em enfermagem e outras disciplinas. Com base em uma perspectiva norte-americana, descreve-se o surgimento de pesquisas em enfermagem unidisciplinar e as trocas de conhecimento que ocorreram entre a enfermagem e outras disciplinas. Discute-se a ascensão da pesquisa interdisciplinar, delineiam-se vários exemplos de participação da enfermagem na interdisciplinaridade, e destacam-se os benefícios proeminentes e dificuldades associadas com a pesquisa interdisciplinar. Defende-se que a colaboração autêntica é necessária para conduzir a pesquisa interdisciplinar significativa e descreve-se como isso pode ser promovido.

La colaboración interdisciplinaria es ampliamente reconocida y considerada esencial para optimizar el desarrollo del conocimiento y la práctica. Sin embargo, la interdisciplinariedad es comúnmente aceptada como un bien incuestionable; rara vez examinada tanto como una fuente de beneficio, así como de dificultad para la enfermería y otras disciplinas. El objetivo de este artículo es examinar críticamente las oportunidades y desafíos que la interdisciplinariedad puede proporcionar para la investigación en enfermería y otras disciplinas. Sobre la base de una perspectiva norteamericana, describe-se el surgimiento de la investigación en enfermería unidisciplinaria y los intercambios de conocimientos que se produjeron entre la enfermería y otras disciplinas. Se discute el aumento de la investigación interdisciplinaria, esbozan-se varios ejemplos de la participación de enfermería en la interdisciplinariedad, y destacan-se los beneficios y las dificultades asociadas con la investigación interdisciplinaria. Argumenta-sé que se requiere auténtica colaboración para llevar a cabo la investigación interdisciplinaria significativa y describe-se la forma en que esto puede ser promovido. .

Hepatic expression patterns in psychosocially high-stressed pigs suggest mechanisms following allostatic principles.

Psychosocial challenges are known to introduce cellular and humoral adaptations in various tissues and organs, including parts of the sympatho-adrenal-medullary system and hypothalamic-pituitary-adrenal axis as well as other peripheral tissue being responsive to cortisol and catecholamines. The liver is of particular interest given its vital roles in maintaining homeostasis and health as well as regulating nutrient utilization and overall metabolism. We aimed to evaluate whether and how response to psychosocial stress is reflected by physiological molecular pathways in liver tissue. A pig mixing experiment was conducted to induce psychosocial stress culminating in skin lesions which reflect the involvement in aggressive behavior and fighting. At 27 weeks of age, animals prone to psychosocially low- and high-stress were assigned to mixing groups. Skin lesions were counted before mixing and after slaughter on the carcass. Individual liver samples (n=12) were taken. The isolated RNA was hybridized on Affymetrix GeneChip porcine Genome Arrays. Relative changes of mRNA abundances were estimated via variance analyses. Molecular routes related to tRNA charging, urea cycle, acute phase response, galactose utilization, and steroid receptor signaling were found to be increased in psychosocially high-stressed animals, whereas catecholamine degradation and cholesterol biosynthesis were found to be decreased. In particular, psychosocially high-stressed animals show decreased expression of catechol-O-methyltransferase (COMT) which has been linked to molecular mechanisms regulating aggressiveness and stress response. The expression patterns of high-stressed animals revealed metabolic alterations of key genes related to energy-mobilizing processes at the expense of energy consuming processes. Thus, the coping following psychosocial challenges involves transcriptional alterations in liver tissue which may be summarized with reference to the concept of allostasis, a strategy which is critical for survival.

Catechol-O-methyltransferase Val158Met polymorphism and altered COMT gene expression in the prefrontal cortex of suicide brains.

Catechol-O-methyltransferase (COMT) plays a key role in the degradation of catecholamine neurotransmitters within the brain. A functional polymorphism COMT Val158Met has been associated with psychiatric disorders including suicidal behavior. In the present study we examined whether this polymorphism was related to COMT mRNA expression in frontal cortical regions, and whether the expression of COMT differed between depressed suicide victims and psychiatric healthy controls. The Val158Met polymorphism was determined by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis. The levels of COMT mRNA expression in the frontopolar cortex (FPC; 29 suicides vs. 27 controls) and orbital frontal cortex (OFC; 19 suicides vs. 15 controls) were significantly increased among depressed individuals that died by suicide relative to those of controls, being up-regulated by approximately 60% and 65% in the FPC and OFC, respectively. Furthermore, among individuals with the Met allele (Met/Met and Met/Val genotypes) who died by suicide COMT mRNA expression was elevated relative to that of the nondepressed Met allele carriers. However, significant differences were not detected between suicides (n=49) and controls (n=72) with respect to the Val158Met genotypic distribution and allelic frequencies. These results are consistent with the perspective that altered COMT mRNA expression in frontal cortical brain regions might contribute to suicide and/or depression, further supporting the role of dysregulation of catecholaminergic pathway genes in the pathophysiology of suicide behaviors.

Effect of a natural mineral-rich water on catechol-O-methyltransferase function.

Catechol-O-methyltransferase (COMT) is a magnesium-dependent, catecholamine-metabolizing enzyme, whose impaired activity has been positively associated with cardiovascular diseases, particularly hypertension. Consumption of some natural mineral-rich waters has been shown to exert protective effects on cardiovascular risk factors, eg. by decreasing arterial blood pressure and blood lipids. However, the molecular mechanisms underlying these effects are still poorly understood. So, the aim of this work was to investigate the effect of natural mineral-rich water ingestion upon liver and adrenal glands COMT expression and activity in Wistar Han rats. Over a seven-week period, animals had access to one of the following three drinking solutions: 1) tap water (control group; TW), 2) tap water with added Na(+) (to make the same concentration as in the MW group (TWNaCl group), or 3) natural mineral-rich water [Pedras Salgadas(®), which is very rich in bicarbonate, and with higher sodium, calcium and magnesium content than control tap water (MW group)]. COMT expression and activity were determined by RT-PCR and HPLC-ED, respectively. A higher hepatic COMT activity was found in the MW group compared with the TW and TWNaCl groups. On the other hand, adrenal gland COMT mRNA expression decreased in the MW group compared to TW group. In conclusion, the ability of natural mineral-rich waters to increase hepatic COMT activity may eventually explain the positive cardiovascular effects associated with the consumption of some natural mineral-rich waters.

Epistatic interaction between COMT and DTNBP1 modulates prefrontal function in mice and in humans.

Cognitive functions are highly heritable and the impact of complex genetic interactions, though undoubtedly important, has received little investigation. Here we show in an animal model and in a human neuroimaging experiment a consistent non-linear interaction between two genes--catechol-O-methyl transferase (COMT) and dysbindin (dys; dystrobrevin-binding protein 1 (DTNBP1))--implicated through different mechanisms in cortical dopamine signaling and prefrontal cognitive function. In mice, we found that a single genetic mutation reducing expression of either COMT or DTNBP1 alone produced working memory advantages, while, in dramatic contrast, genetic reduction of both in the same mouse produced working memory deficits. We found evidence of the same non-linear genetic interaction in prefrontal cortical function in humans. In healthy volunteers (N=176) studied with functional magnetic resonance imaging during a working memory paradigm, individuals homozygous for the COMT rs4680 Met allele that reduces COMT enzyme activity showed a relatively more efficient prefrontal engagement. In contrast, we found that the same genotype was less efficient on the background of a dys haplotype associated with decreased DTNBP1 expression. These results illustrate that epistasis can be functionally multi-directional and non-linear and that a putatively beneficial allele in one epistastic context is a relatively deleterious one in another. These data also have important implications for single-locus association analyses of complex traits.