Fatty acids involved in signal cross-talk between cell membrane and nucleus

Traumatic Acid Reduces Oxidative Stress and Enhances Collagen Biosynthesis in Cultured Human Skin Fibroblasts

Traumatic acid (TA) is a plant hormone (cytokinin) that in terms of chemical structure belongs to the group of fatty acids derivatives. It was isolated from Phaseolus vulgaris. TA activity and its influence on human cells and organism has not previously been the subject of research. The aim of this study was to examine the effects of TA on collagen content and basic oxidative stress parameters, such as antioxidative enzyme activity, reduced glutathione, thiol group content, and lipid peroxidation in physiological conditions. The results show a stimulatory effect of TA on tested parameters. TA caused a decrease in membrane phospholipid peroxidation and exhibited protective properties against ROS production. It also increases protein and collagen biosynthesis and its secretion into the culture medium. The present findings reveal that TA exhibits multiple and complex activity in fibroblast cells in vitro. TA, with its activity similar to unsaturated fatty acids, shows antioxidant and stimulatory effects on collagen biosynthesis. It is a potentially powerful agent with applications in the treatment of many skin diseases connected with oxidative stress and collagen biosynthesis disorders.

The expression of fatty acid metabolism-associated proteins is correlated with the prognosis of meningiomas

The expression of fatty acid metabolism-associated proteins is correlated with the prognosis of meningiomas. Meningioma is a common tumor of the nervous system; however, reliable prognostic markers for meningioma are currently insufficient. High fatty acid synthase (FAS) expression occurs in many tumors, and is associated with tumor progression and grade. Few studies have previously investigated fatty acid metabolism in meningioma; thus, in this study, we investigated the expression of FAS and brain fatty acid-binding protein (BFABP) proteins in all grades of meningioma and determined the association to meningioma grade, invasiveness, recurrence, and progression. We determined expression levels of FAS and BFABP in all grade meningiomas by immunohistochemical analysis in 314 patients diagnosed with meningioma. The expression levels of FAS and BFABP increased significantly in correlation with meningioma grade (p < 0.01). Compared with benign meningioma, the expression levels of FAS and BFABP were significantly higher in brain invasive meningioma (p < 0.01). Compared with nonrecurrent meningioma (benign meningioma), the expression of FAS was also increased in recurrent meningioma (p < 0.01). The expression of fatty acid metabolism-associated proteins potentially correlates with meningioma grade, invasiveness, aggressiveness, and recurrent status and provides evidence for a novel therapeutic target for meningioma.

Molecular cloning and functional analysis of the fatty acid-binding protein (Sp-FABP) gene in the mud crab (Scylla paramamosain)

Intracellular fatty acid-binding proteins (FABPs) are multifunctional cytosolic lipid-binding proteins found in vertebrates and invertebrates. In this work, we used RACE to obtain a full-length cDNA of Sp-FABP from the mud crab Scylla paramamosain. The open reading frame of the full length cDNA (886 bp) encoded a 136 amino acid polypeptide that showed high homology with related genes from other species. Real-time quantitative PCR identified variable levels of Sp-FABP transcripts in epidermis, eyestalk, gill, heart, hemocytes, hepatopancreas, muscle, ovary, stomach and thoracic ganglia. In ovaries, Sp-FABP expression increased gradually from stage I to stage IV of development and decreased in stage V. Sp-FABP transcripts in the hepatopancreas and hemocytes were up-regulated after a bacterial challenge with Vibrio alginnolyficus. These results suggest that Sp-FABP may be involved in the growth, reproduction and immunity of the mud crab.

Bipolar disorder

Bipolar disorder's unique combination of three characteristics - clear genetic diathesis, distinctive clinical features, early availability of an effective treatment (lithium) - explains its special place in the history of psychiatry and its contribution to the current explosive growth of neuroscience. This article looks at the state of the art in bipolar disorder from the vantage point of: (i) genetics (possible linkages on chromosomes 18 and 21q, polygenic hypothesis, research into genetic markers); (ii) diagnosis (new focus on the subjective aspects of bipolar disorder to offset the current trend of underdiagnosis due to overreliance on standardized interviews and rating scales); (iii) outcome (increase in treatment-resistant forms signaling a change in the natural history of bipolar disorder); (iv) pathophysiology (research into circadian biological rhythms and the kindling hypothesis to explain recurrence); (v) treatment (emergence of the anticonvulsants, suggested role of chronic antidepressant treatment in the development of treatment resistance); (vi) neurobiology (evaluation of regulatory function in relation to affective disturbances, role of postsynaptic second-messenger mechanisms, advances in functional neuroimaging); and (vii) psychosocial research (shedding overly dualistic theories of the past to understand the mind and brain as an entity, thus emphasizing the importance of balancing the psychopharmacological and psychotherapeutic approaches). Future progress in the understanding and treatment of bipolar disorder will rely on successful integration of the biological and psychosocial lines of investigation.

Adipocyte differentiation-specific gene transcriptional response to C18 unsaturated fatty acids plus insulin

Adipocyte differentiation (AD) and AD-specific gene expression was studied in 3T3-L1 cells in response to oleic acid (OA) or linoleic acid (LA) alone and in combination with insulin. This system facilitated the study of key regulators of adipogenesis PPARγ and C/EBPα and other AD-specific genes, in the absence of dexamethasone (DEX) and isobutyl-1-methyl xanthine (IBMX) (components of the traditional AD medium, DMI). Lipid accumulation and expression levels of AD-specific genes were enhanced by both OA and LA in the presence of insulin but not by OA or LA alone. Gene expression levels of PPARγ, C/EBPα, FABP4, and SREBP1c induced by OA plus insulin, were comparable to DMI medium, by study day 10. The response to long-chain fatty acids (LCFA) plus insulin in the presence or absence of LY294002 demonstrated that the insulin-induced PI 3-kinase pathway regulates AD and AD-specific gene expression levels. Insulin treatment in the presence or absence of genistein suggested that genistein invoked inhibition of AD and AD-specific gene expression. In contrast when LCFA were also included with insulin, the presence of genistein invoked a pronounced and opposite effect on AD to that in the absence of LCFA. This effect may be modulated via C/EBPα as C/EBPα but not PPARγ expression patterns closely reflected the changes in AD. DMI invoked a rapid expression of all genes studied, and LCFA plus insulin invoke more gradual increases in gene expression, to similar levels to those invoked by DMI. The model system is valuable for study of transactivators and response elements of PPARγ and C/EBPα genes.

New insights into "GPR40-CREB interaction in adult neurogenesis" specific for primates

Polyunsaturated fatty acids (PUFA), such as docosahexaenoic (DHA) and arachidonic acids (ARA) are known to be closely related to the brain development and also have beneficial effects on adult neurogenesis, learning, and mental disorders. Although PUFA were demonstrated as ligands for G protein-coupled receptor 40 (GPR40), their signaling mechanism in the brain, especially in the neurogenic niche, remains unknown. Using a monkey model of ischemia-enhanced hippocampal neurogenesis, we studied the spatial correlation between GPR40 and the phosphorylated cAMP response element-binding protein (pCREB), a transcription factor involved in adult neurogenesis, learning and memory. Furthermore, the brain-derived neurotrophic factor (BDNF) and its receptor tropomyosin receptor kinase B (TrkB), both being downstream gene transcripts of pCREB, were studied. Similar to the dynamic change of GPR40 as the authors reported previously, pCREB was up-regulated significantly after transient global brain ischemia on Western blots, and this was associated with an enhanced hippocampal neurogenesis. Immunofluorescence microscopic analysis showed that GPR40 and pCREB expression patterns were completely identical, and they were coexpressed in both mature and newborn neurons as well as in the astrocytes residing in the subgranular zone (SGZ). GPR40/pCREB double-positive cells significantly increased in the SGZ on day 15 after ischemia. The mature form of BDNF (mBDNF) and TrkB receptor showed no remarkable changes on Western blots, although proBDNF (precursor of mBDNF) was maximal on day 9. Immunofluorescence microscopy showed that the newborn neurons expressed BDNF, but not TrkB. These results altogether suggest that PUFA, GPR40, pCREB, and BDNF may be engaged in the same signaling pathway to promote neurogenesis in the adult primate hippocampus.

Modulation of cyclin D1 and early growth response factor-1 gene expression in interleukin-1beta-treated rat smooth muscle cells by n-6 and n-3 polyunsaturated fatty acids

The proliferation of smooth muscle cells (SMC) is a key event in the development of atherosclerosis. In addition to growth factors or cytokines, we have shown previously that n-3 polyunsaturated fatty acids (PUFAs) act in opposition to n-6 PUFAs by modulating various steps of the inflammatory process. We have investigated the molecular mechanisms by which the incorporation of the n-6 PUFA, arachidonic acid, increases the proliferation of rat SMC treated with interleukin-1beta, while the n-3 PUFAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), elicit no mitogenic response. Incorporation of EPA or DHA into SMC, which are then activated by interleukin-1beta to mimic inflammation, decreases promoter activity of the cyclin D1 gene and phosphorylation of the retinoblastoma protein. Together, our data demonstrate that n-3 effects are dependent on the Ras/Raf-1/extracellular signal regulated kinase (ERK)/mitogen-activated protein kinase pathway, and that down-regulation of the cyclin D1 promoter activity is mediated by the specific binding of the early growth response factor-1. Finally, we have shown that the incorporation of EPA and DHA also increased the concentration of caveolin-1 and caveolin-3 in caveolae, which correlated with n-3 PUFA inhibition of SMC proliferation through the mitogen-activated protein kinase pathway. We provide evidence indicating that, in contrast to n-6 PUFAs, n-3 PUFAs exert antiproliferative effects on SMC through the mitogen-activated protein kinase/ERK pathway.

A Galphas protein-coupled membrane receptor, distinct from the classical oestrogen receptor, transduces rapid effects of oestradiol on [Ca2+]i in female rat distal colon

We examined the hypothesis whether rapid non-genomic effects of oestradiol (E2) on [Ca(2+)](i) are mediated via a membrane-located oestrogen receptor (ER) and further elucidated the signalling pathways involved in rapid non-genomic effects of E2 on [Ca(2+)](i) in distal colonic crypts. Basal [Ca(2+)](i) was significantly increased, within minutes, in response to physiological concentrations of E2. Oestradiol linked to bovine serum albumin (E2-BSA), which renders the E2 membrane impermeable, rapidly increased [Ca(2+)](i) suggesting mediation by a membrane surface receptor. A classical ER is not involved however, as no inhibition of either the E2 or E2-BSA [Ca(2+)](i) response was seen in the presence of the classical ER antagonist ICI 182,780. Treatment with the Galphas inhibitor cholera toxin abolished both E2 and E2-BSA induced Ca(2+) increases. In contrast, treatment with pertussis toxin, an inhibitor of Galphai and Galphao, had no inhibitory effect. Following subsequent additions of E2 and E2-BSA, no further increases in [Ca(2+)](i) were observed, indicating receptor desensitisation. The E2-induced increase in [Ca(2+)](i) was completely abolished by the PKCdelta-specific inhibitor rottlerin, whereas Go6976, an inhibitor of Ca(2+)-sensitive PKC isoforms, was without inhibitory effect. The phospholipase A2 antagonist, quinacrine, and the COX1 inhibitor, indomethacin, abolished the E2-induced increase in [Ca(2+)](i). MAP kinase activation is not involved in rapid stimulatory effects of E2 on [Ca(2+)](i) as the specific inhibitor PD98059 did not inhibit the E2 response. These results demonstrate that rapid E2-induced stimulation of [Ca(2+)](i), in femal rat distal colonic crypts, occurs via a CTx-sensitive Galphas-coupled membrane receptor distinct from the classical ER. PKCdelta and fatty acids are involved in the E2 signalling pathway. In contrast, PKCalpha and MAP kinase are not required.

Cardiac (n-3) non-esterified fatty acids are selectively increased in fish oil-fed pigs following myocardial ischemia

The effect of fish oil supplementation on the nonesterified fatty acid (NEFA) concentration and composition in the normoxic and hypoxic myocardium of pigs was examined. Two groups of female pigs (n = 7) were fed a diet supplemented with either 5 g beef tallow/kg (as control) or 5 g fish oil/kg (MaxEPA) rich in (n-3) fatty acids. After 6 wk of supplementation, the pigs were anesthetized, hearts exposed by thoracotomy followed by occlusion of the left anterior descending artery. Normoxic and hypoxic regions of the heart were examined for NEFA concentration and composition by using a combination of thin layer and gas chromatography. Nonesterified (n-6) and (n-3) fatty acid concentration and composition differed significantly between the two groups in both the normoxic and hypoxic areas of the heart. Eicosapentaenoic and docosahexaenoic acid concentration in the NEFA fraction of the normoxic myocardium were higher in the fish oil group than in the beef tallow group (P < 0.001). In the fish oil-fed pigs, the (n-3) NEFA concentration was significantly higher in the hypoxic compared to the normoxic region of the heart. The fish oil-fed group had lower levels of arachidonic acid in the NEFA fraction compared to the beef tallow-fed group, whereas the hypoxic myocardium had higher levels of arachidonic acid, regardless of the dietary fat supplementation. Despite large differences in the proportions of saturated fatty acids in the experimental diets, there was little or no difference in the saturated fatty acid content of cardiac phospholipid and NEFA fractions. Following myocardial ischemia, (n-3) fatty acids in the NEFA fractions were selectively increased in the fish oil-fed pigs, implicating the possible role of nonesterified (n-3) polyunsaturated fatty acids in the prevention of arrhythmias.

Specific modifications of phosphatidylinositol and nonesterified fatty acid fractions in cultured porcine cardiomyocytes supplemented with n-3 polyunsaturated fatty acids

Mechanisms for the antiarrhythmic effect of n-3 polyunsaturated fatty acids (PUFA) are currently being investigated using isolated cardiac myocytes. It is still not known whether the incorporation of n-3 PUFA into membrane phospholipids is a prerequisite for its protective action or if n-3 PUFA exert antiarrhythmic effects in their nonesterified form as demonstrated by recent studies. Adult porcine cardiomyocytes were grown in media supplemented with arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). After 24 h, analysis of total lipids showed that the myocytes were enriched with the respective fatty acids compared to control cells. Large proportions of all three fatty acids supplemented (69% AA, 72% DHA, and 66% EPA) remained unesterified. Fatty acid analyses of total phospholipids (PL) revealed that the incorporation of EPA and DHA, though small, was significantly different (P<0.05) from that of the control cells. The PL fraction was further separated into phosphatidylinositol (PI), phosphatidylethanolamine, phosphatidylcholine, and phosphatidylserine to study the pattern of incorporation of the fatty acids in these fractions. It became apparent that EPA and DHA were selectively incorporated into the PI fraction. This study demonstrates that in adult porcine cardiomyocytes, the n-3 PUFA supplementation selectively modulates two important lipid fractions, nonesterified fatty acid and PI, which were implicated in the mechanisms of prevention of cardiac arrhythmias.