Beneficial effects of omega-3 fatty acid supplementation in schizophrenia: possible mechanisms.

BACKGROUND: Schizophrenia is a serious long-term psychotic disorder marked by positive and negative symptoms, severe behavioral problems and cognitive function deficits. The cause of this disorder is not completely clear, but is suggested to be multifactorial, involving both inherited and environmental factors. Since human brain regulates all behaviour, studies have focused on identifying changes in neurobiology and biochemistry of brain in schizophrenia. Brain is the most lipid rich organ (approximately 50% of brain dry weight). Total brain lipids is constituted of more than 60% of phospholipids, in which docosahexaenoic acid (DHA, 22:6n-3) is the most abundant (more than 40%) polyunsaturated fatty acid (PUFA) in brain membrane phospholipids. Results from numerous studies have shown significant decreases of PUFAs, in particular, DHA in peripheral blood (plasma and erythrocyte membranes) as well as brain of schizophrenia patients at different developmental phases of the disorder. PUFA deficiency has been associated to psychotic symptoms and cognitive deficits in schizophrenia. These findings have led to a number of clinical trials examining whether dietary omega-3 fatty acid supplementation could improve the course of illness in patients with schizophrenia. Results are inconsistent. Some report beneficial whereas others show not effective. The discrepancy can be attributed to the heterogeneity of patient population. METHODS: In this review, results from recent experimental and clinical studies, which focus on illustrating the role of PUFAs in the development of schizophrenia were examined. The rationale why omega-3 supplementation was beneficial on symptoms (presented by subscales of the positive and negative symptom scale (PANSS), and cognitive functions in certain patients but not others was reviewed. The potential mechanisms underlying the beneficial effects were discussed. RESULTS: Omega-3 fatty acid supplementation reduced the conversion rate to psychosis and improved both positive and negative symptoms and global functions in adolescents at ultra-high risk for psychosis. Omega-3 fatty acid supplementation could also improve negative symptoms and global functions in the first-episode patients with schizophrenia, but improve mainly total or general PANSS subscales in chronic patients. Patients with low PUFA (particularly DHA) baseline in blood were more responsive to the omega-3 fatty acid intervention. CONCLUSION: Omega-3 supplementation is more effective in reducing psychotic symptom severity in young adults or adolescents in the prodromal phase of schizophrenia who have low omega-3 baseline. Omega-3 supplementation was more effective in patients with low PUFA baseline. It suggests that patients with predefined lipid levels might benefit from lipid treatments, but more controlled clinical trials are warranted.

Effects of ultrasonic and microwave pretreatments on lipid extraction of microalgae.

The extraction of lipids from microalgal cells using ultrasonic and microwave pretreatments is mechanistically evaluated based on the distribution of cell fragments, the lipid content analysis, the scanning electron microscopic (SEM) observation of ruptured microalgal cells, and the analysis of fatty acids. The results indicate that microwave pretreatment extracts lipids more rapidly and efficiently as compared to ultrasonic pretreatment. The rupture of cells in the microwave process is due to the tremendous pressure caused by the rapid heating of the moisture inside the microalgal cells, whereas in the ultrasonic process the microalgal cells are ruptured by shock waves from cavitation bubbles outside the cells. The fatty acid composition of the respective lipids extracted via the two types of pretreatment did not vary significantly from one another. These results demonstrate that the microwave process is rapid and more effective than the ultrasonic process for lipid extraction from microalgae.

Exploring the pivotal variables of tongue diagnosis between patients with acute ischemic stroke and health participants.

Background and aim: Stroke is a major cause of disability worldwide, and ischemic stroke is the most common type of stroke. The prevention and treatment of ischemic stroke remain a challenge worldwide. Traditional Chinese medicine (TCM) is often sought to provide an alternative therapy for the prevention and rehabilitation intervention of ischemic stroke in Taiwan. Therefore, this study explored the pivotal variables of tongue diagnosis among acute ischemic stroke and healthy participants in middle and older age. Experimental procedure: This was a cross-sectional and case-controlled study. Data were collected from 99 patients with acute ischemic stroke and 286 healthy participants who received tongue diagnoses at Changhua Christian Hospital (CCH) from September 1, 2014, to December 31, 2016. Tongue features were extracted using the automatic tongue diagnosis system. Nine tongue features, including tongue shape, tongue color, fur thickness, fur color, saliva, tongue fissures, ecchymoses, teeth marks, and red spots were analyzed. Results and conclusion: Objective image analysis techniques were used to identify significant differences in the many tongue features between patients with acute ischemic stroke and individuals without stroke. According to the logistic regression analysis, pale tongue color (OR:5.501, p = 0.001), bluish tongue color (OR:4.249, p = 0.014), ecchymoses (OR:1.058, p < 0.001), and tongue deviation angle (OR:1.218, p < 0.001) were associated with significantly increased odds ratios for acute ischemic stroke. The research revealed that tongue feature abnormalities were significantly related to the occurrence of ischemic stroke.

Eicosadienoic acid differentially modulates production of pro-inflammatory modulators in murine macrophages.

Eicosadienoic acid (Δ11,14-20:2; EDA) is a rare, naturally occurring n-6 polyunsaturated fatty acid (PUFA) found mainly in animal tissues. EDA is elongated from linoleic acid (LA), and can also be metabolized to dihomo-γ-linolenic acid (DGLA), arachidonic acid (AA), and sciadonic acid (Δ5,11,14-20:3; SCA). Although, the metabolism of EDA has been extensively studied, there are few reports regarding how EDA might affect inflammatory processes. The objective of this study was to determine the effect of EDA on the n-6 PUFA composition and inflammatory response of murine RAW264.7 macrophages to lipopolysaccharide (LPS). EDA was taken up rapidly by macrophages and metabolized to SCA, and the percentages of both fatty acids increased in cellular phospholipids in a dose-dependent manner. The incorporation of EDA into macrophage lipids increased the proportions of LA, DGLA, and AA as well, and reduced the proportion of total monounsaturated fatty acids. When LPS were applied to the macrophages, EDA decreased the production of nitric oxide (NO), and increased that of prostaglandin E(2) (PGE(2)) and tumor necrotic factor-α. The modulation of NO and PGE(2) was due, in part, to the modified expression of inducible nitric oxide synthase and type II cyclooxygenase. The differential effects of EDA on pro-inflammatory mediators might attribute to the negative feedback mechanism associated with prolonged inflammation. Furthermore, EDA was a weaker pro-inflammatory agent than LA, and not as anti-inflammatory as SCA. This study shows that EDA can modulate the metabolism of PUFA and alter the responsiveness of macrophages to inflammatory stimulation.

The Relationship between Ischemic Stroke Patients with and without Retroflex Tongue: A Retrospective Study.

Background. Patients suffering from stroke exhibit different levels of capability in retroflex tongues, in our clinical observation. This study aims to derive the association of tongue retroflexibility with the degree of severity for stroke patients. Methods. All ischemic stroke patients were collected from August 2010 to July 2013 in the Stroke Center, Changhua Christian Hospital, Taiwan. All participants underwent medical history collection and clinical examination, including tongue images captured by ATDS. Statistical analysis was performed to compare the differences of ischemic stroke patients with and without retroflex tongue. Result. Among the total of 308 cases collected, 123 patients cannot retroflex their tongues, that is, the non-RT group. The length of stay in the non-RT group, 32.0 ± 21.5, was longer than those of the RT counterparts, 25.9 ± 14.4 (p value: 0.007). The NIHSS on admission, 14.1 ± 7.8 versus 8.9 ± 5.2, was higher and the Barthel Index upon admission, 18.6 ± 20.7 and 35.0 ± 24.2, was lower for the non-RT patients than that of the RT counterparts. Also, the non-RT patients account for 60.2% and 75.6% for Barthel Index ≤ 17 and NIHSS ≥ 9, respectively. Conclusion. The stroke patients in non-RT group showed significantly poor prognosis and were more serious in the degree of severity and level of autonomy than RT group, indicating that the ability to maneuver tongue retroflex can serve as a simple, reliable, and noninvasive means for the prognosis of ischemic stroke patients.

Differential effects of n-3 polyunsaturated fatty acids on metabolic control and vascular reactivity in the type 2 diabetic ob/ob mouse.

Diets rich in monounsaturated fatty acids (MUFA) are recommended for individuals with type 2 diabetes mellitus (T2DM). The American Heart Association recommends increasing intakes of n-3 polyunsaturated fatty acids (PUFA) to reduce the risk of vascular disease in high-risk individuals; however, the long-term effects of these bioactive fatty acids on glucose metabolism in insulin resistance are controversial. The present studies were conducted to evaluate the effects of diets rich in both MUFA and alpha linolenic acid (C18:3n-3, ALA), eicosapentaenoic acid (C20:5n-3, EPA), or docosahexaenoic acid (C22:6n-3, DHA), on glycemic control and other parameters related to vascular health in a mouse model of T2DM and insulin resistance. Male ob/ob mice (n = 15 per treatment) were fed 1 of 4 lipid-modified formula diets (LFDs) for 4 weeks: (1) MUFA control, (2) ALA blend, (3) EPA blend, and (4) DHA blend. A portion of a MUFA-rich lipid blend in the control LFD was replaced with 11% to 14% energy as n-3 PUFA. After 4 weeks, plasma glucose response to a standard meal (1.5 g carbohydrate/kg body weight) and insulin challenge (2 U/kg body weight, IP) was assessed, and samples were collected for analysis of glucose, insulin, and lipids. Vascular reactivity of isolated aortic rings was assessed in an identical follow-up study. The results showed that insulin-resistant mice fed an LFD with EPA and/or DHA blends had significantly (P < .05) lower triglycerides and free fatty acids, but insulin sensitivity and fasting plasma glucose were not improved. However, mice fed with the ALA blend had significantly improved insulin sensitivity when compared to those fed with other LFD (P < .05). Animals fed an LFD with n-3 PUFA from marine or plant sources showed significantly improved vascular responses as compared with the MUFA-rich LFD (E(max), P < .05) and ob/ob reference mice consuming chow (E(max) and pEC(50), P < .05). In summary, long-term consumption of LFD with n-3 PUFAs improved blood lipids and vascular function in an animal model of insulin resistance and T2DM; however, only MUFA-rich LFD with ALA also improved both insulin sensitivity and glycemic responses. Further studies of MUFA-rich LFD with ALA with individuals who have T2DM are warranted.

Identification of two novel microalgal enzymes involved in the conversion of the omega3-fatty acid, eicosapentaenoic acid, into docosahexaenoic acid.

Marine microalgae such as Pavlova and Isochrysis produce abundant amounts of the omega3-PUFAs (polyunsaturated fatty acids), EPA (eicosapentaenoic acid, 20:5n-3) and DHA (docosahexaenoic acid, 22:6n-3). The pathway leading to the conversion of EPA into DHA in these lower eukaryotes is not well established although it is predicted to involve an elongation step, catalysed by an elongating enzyme complex, leading to the conversion of EPA into omega3-DPA (omega-3-docosapentaenoic acid, 22:5n-3); followed by a desaturation step, catalysed by a Delta4-desaturase, which results in the conversion of DPA into DHA. To date, the enzymes involved in the elongation of EPA have not been identified from any lower eukaryote. In the present study, we describe the identification of microalgal genes involved in the two-step conversion of EPA into DHA. By expressed sequence tag analysis, a gene (pavELO) encoding a novel elongase was identified from Pavlova, which catalysed the conversion of EPA into omega3-DPA in yeast. Unlike any previously identified elongase from higher or lower eukaryotes, this enzyme displayed unique substrate specificity for both n-6 and n-3 C20-PUFA substrates, with no activity towards any C18- or C22-PUFA substrates. In addition, a novel Delta4-desaturase gene (IgD4) was isolated from Isochrysis, which was capable of converting omega3-DPA into DHA, as well as adrenic acid (22:4n-6) into omega6-DPA. Yeast co-expression studies, with pavELO and IgD4, revealed that these genes were capable of functioning together to carry out the two-step conversion of EPA into DHA.

A novel omega3-fatty acid desaturase involved in the biosynthesis of eicosapentaenoic acid.

Long-chain n-3 PUFAs (polyunsaturated fatty acids) such as EPA (eicosapentaenoic acid; 20:5 n-3) have important therapeutic and nutritional benefits in humans. In plants, cyanobacteria and nematodes, omega3-desaturases catalyse the formation of these n-3 fatty acids from n-6 fatty acid precursors. Here we describe the isolation and characterization of a gene ( sdd17 ) derived from an EPA-rich fungus, Saprolegnia diclina, that encodes a novel omega3-desaturase. This gene was isolated by PCR amplification of an S. diclina cDNA library using oligonucleotide primers corresponding to conserved regions of known omega3-desaturases. Expression of this gene in Saccharomyces cerevisiae, in the presence of various fatty acid substrates, revealed that the recombinant protein could exclusively desaturate 20-carbon n-6 fatty acid substrates with a distinct preference for ARA (arachidonic acid; 20:4 n-6), converting it into EPA. This activity differs from that of the known omega3-desaturases from any organism. Plant and cyanobacterial omega3-desaturases exclusively desaturate 18-carbon n-6 PUFAs, and a Caenorhabditis elegans omega3-desaturase preferentially desaturated 18-carbon PUFAs over 20-carbon substrates, and could not convert ARA into EPA when expressed in yeast. The sdd17 -encoded desaturase was also functional in transgenic somatic soya bean embryos, resulting in the production of EPA from exogenously supplied ARA, thus demonstrating its potential for use in the production of EPA in transgenic oilseed crops.

Enzymes for transgenic biosynthesis of long-chain polyunsaturated fatty acids.

Polyunsaturated fatty acids (PUFAs) are important for the normal development and function of all organisms, and are essential in maintaining human health. Impaired PUFA metabolism is thought to be associated with pathogenesis of many chronic diseases. Dietary supplementation of PUFAs, such as gamma-linolenic acid, arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid, which bypass the defective or dysfunctional steps of the biosynthetic pathway has been found to significantly alleviate the symptoms of the disease. These findings have drawn a great deal of interest from general public and food manufacturers. As the demand of these beneficial PUFAs has drastically increased in recent years, there are also increasing efforts in finding the alternate sources of PUFAs that are more economical and sustainable. One option is to modify the oil-seed crops to produce PUFAs through genetic engineering technique. This review examines the isolation, identification and expression of genes encoding the enzymes required for the biosynthesis of the above mentioned PUFAs in plants.

Effect of long-term dietary supplementation of high-gamma-linolenic canola oil versus borage oil on growth, hematology, serum biochemistry, and N-6 fatty acid metabolism in rats.

Dietary supplementation of a high-gamma-linolenic acid canola oil (HGCO) containing approximately 36% (w/w) of gamma-linolenic acid (GLA, 18:3n-6) from the seeds of a genetically transformed canola strain, was assessed for its long-term biological effects. Growing Sprague-Dawley rats (n = 30) were fed a purified AIN93G diet containing 5, 10, or 15% (w/w) of HGCO as the fat source. For comparison, a separate group of rats (n = 10) was given the diet containing 15% (w/w) of borage oil (BO), which contained 22% (w/w) of GLA. After 12 weeks of feeding, the growth, relative organ weights, hematology, and serum biochemistry were found to be similar among rats fed the 5, 10, and 15% HGCO diets. The GLA levels in plasma and liver phospholipids (PL) were also similar. However, the levels of GLA in peripheral tissues (muscle PL and adipose triacylglycerols) were significantly higher in rats fed the 10 and 15% HGCO diets than those fed the 5% HGCO diet. When the above biologic parameters were compared between the 15% HGCO and 15% BO dietary groups, there were no significant differences except for lower final body weights and higher tissue levels of GLA, dihomo-gamma-linolenic acid (20:3n-6) and arachidonic acid (20:4n-6) in the 15% HGCO dietary group as compared with the 15% BO dietary group. This is due to a higher GLA content and possibly a more favorable stereospecific distribution of GLA in HGCO. Overall, long-term (12-week) feeding with diets containing up to 15% HGCO resulted in no adverse effects on growth, organ weight, hematology and serum biochemistry as compared to the diet containing 15% BO, suggesting that HGCO may be a safe alternative source of GLA.

Polyphosphoinositides suppress the adhesion of Haemophilus influenzae to pharyngeal cells.

BACKGROUND: One of the primary causes of otitis media (OM), an inflammation of the middle ear, is the bacterium Haemophilus influenzae (HI). OM often occurs to young children, and is mostly treated with antibiotics. Due to concerns over bacterial resistance toward antibiotics, reliable prophylactic treatments such as administrating anti-adhesion agents are now viewed as viable alternatives. RESULTS: The present study tested the feasibilty of using phosphoinositides as anti-adhesion agents against HI cells. Cells of non-typeable HI were radiolabeled with 111- indium-oxine, pre-incubated with various individual phosphoinositides for 15 minutes at 37 degrees C, and incubated with a monolayer of human pharynx carcinoma (DT 562) cells for 20 minutes at 37 degrees C. The result showed that at 0.1 mg/mL dipalmitoylphosphatidylinositol-3,4-diphosphate (PI-3,4-PP) had the highest anti-adhesion activity, followed by phosphatidylinositol-3-phosphate (PI-3-P) and phosphatidylinositol-4-phosphate (PI-4-P). The anti-adhesion activity of PI-3,4-PP was dose-dependent ranging from 0.006 to 0.1 mg/mL. In addition, results from an in vivo study demonstrated that pre-incubation of HI cells with PI-3,4-PP at 1 mg/mL suppressed the growth of HI in nasopharynx of neonatal rats. CONCLUSIONS: These findings suggest that PI-3-P and PI-4-P and more so PI-3,4-PP may serve as prophylactic agents against HI adhesion and colonization.

Phase angle correlates with n-3 fatty acids and cholesterol in red cells of Nigerian children with sickle cell disease.

OBJECTIVE: To determine the cholesterol content and fatty acid composition of red cell membrane phospholipids (PL) of children with sickle cell disease (SCD) and to correlate these levels with whole body phase angle that is related to the integrity and function of cell membranes. STUDY DESIGN: Blood samples were obtained from 69 children with SCD and 72 healthy age- and gender-matched controls in Nigeria for the determination of the cholesterol content and proportions of fatty acids in red cell PL. Bioelectrical impedance analysis was used to obtain resistance (R) and reactance (Xc) from which phase angle was calculated as arctan Xc/R. Cholesterol (normalized to lipid phosphorus) and the proportions of individual fatty acids were correlated with phase angle. RESULTS: The proportions of palmitic (p < 0.001), stearic acid (p = 0.003) and cholesterol (p < 0.001) were significantly higher in the red cells of children with SCD, whereas the proportions of arachidonic acid and docosahexaenoic acid were reduced (p = 0.03 and < 0.001, respectively) compared to controls. The phase angle was inversely correlated with the proportions of palmitic acid (p = 0.03) and oleic acid (p < 0.001) and cholesterol (p = 0.003). Three n-3 polyunsaturated fatty acids-eicosapentaenoic acid, docosapentaenoic acid and docosahexaenoic acid- were positively correlated with phase angle (p < 0.001). CONCLUSIONS: The fatty acid composition and cholesterol content of tissue membranes in SCD correlate with the phase shift measured by bioelectrical impedance analysis. Phase angle measurements may provide a non-invasive method for monitoring interventions aimed at altering the lipid composition of membranes.

Effects of high-gamma-linolenic acid canola oil compared with borage oil on reproduction, growth, and brain and behavioral development in mice.

Previous research in rats and mice has suggested that gamma-linolenic acid (GLA) derived from borage oil (BO: 23% GLA) may be an appropriate source for increasing levels of long-chain n-6 FA in the developing brain. Recently, transgenic technology has made available a highly enriched GLA seed oil from the canola plant (HGCO: 36% GLA). The first objective of this study was to compare the effects of diets containing equal levels of GLA (23%) from either BO or HGCO on reproduction, pup development, and pup brain FA composition in mice. The second objective was to compare the effects of the HGCO diluted to 23% GLA (GLA-23) with those of undiluted HGCO containing 36% GLA (GLA-36). The diets were fed to the dams prior to conception and throughout pregnancy and lactation, as well as to the pups after weaning. The behavioral development of the pups was measured 12 d after birth, and anxiety in the adult male offspring was assessed using the plus maze. The findings show that despite equivalent levels of GLA, GLA-23 differed from BO in that it reduced pup body weight and was associated with a slight increase in neonatal pup attrition. However, there were no significant effects on pup behavioral development or on performance in the plus maze. An increase in dietary GLA resulted in an increase in brain 20:4n-6 and 22:4n-6, with a corresponding decrease in 22:6n-3. Again, despite their similar levels of GLA, these effects tended to be larger in GLA-23 than in BO. In comparison with GLA-23, GLA-36 had larger effects on growth and brain FA composition but no differences with respect to effects on reproduction and behavioral development. These findings suggest that the HGCO can be used as an alternative source of GLA.

Identification and expression of mammalian long-chain PUFA elongation enzymes.

In mammalian cells, Sprecher has proposed that the synthesis of long-chain PUFA from the 20-carbon substrates involves two consecutive elongation steps, a delta6-desaturation step followed by retroconversion (Sprecher, H., Biochim. Biophys. Acta 1486, 219-231, 2000). We searched the database using the translated sequence of human elongase ELOVL5, whose encoded enzyme elongates monounsaturated and polyunsaturated FA, as a query to identify the enzyme(s) involved in elongation of very long chain PUFA. The database search led to the isolation of two cDNA clones from human and mouse. These clones displayed deduced amino acid sequences that had 56.4 and 58% identity, respectively, to that of ELOVL5. The open reading frame of the human clone (ELOVL2) encodes a 296-amino acid peptide, whereas the mouse clone (Elovl2) encodes a 292-amino acid peptide. Expression of these open reading frames in baker's yeast, Saccharomyces cerevisiae, demonstrated that the encoded proteins were involved in the elongation of both 20- and 22-carbon long-chain PUFA, as determined by the conversion of 20:4n-6 to 22:4n-6, 22:4n-6 to 24:4n-6, 20:5n-3 to 22:5n-3, and 22:5n-3 to 24:5n-3. The elongation activity of the mouse Elovl2 was further demonstrated in the transformed mouse L cells incubated with long-chain (C20- and C22-carbon) n-6 and n-3 PUFA substrates by the significant increase in the levels of 24:4n-6 and 24:5n-3, respectively. This report demonstrates the isolation and identification of two mammalian genes that encode very long chain PUFA specific elongation enzymes in the Sprecher pathway for DHA synthesis.

Abnormalities in the fatty-acid composition of the serum phospholipids of stroke patients.

The incidence of cardiovascular diseases, stroke, and myocardial infarction is increasing in sub-Saharan Africa. Since dietary polyunsaturated fatty acids (PUFA) are protective of the cardiovascular system in humans, we were interested in the question of the PUFA status of adults in northern Nigeria who had experienced a recent stroke. We collected blood from 21 consecutive admissions for stroke (15 male patients, mean age 39.3 years and six females, mean age 40.7 years) to the Federal Medical Centre in Gombe, Nigeria and analyzed the fatty-acid composition of the serum phospholipids. Blood was collected from 30 healthy controls for comparison. The contribution palmitic acid made to the fatty-acid total was greatly decreased in the phospholipids of the stroke patients (29.2% versus 37.2 %, p < 0.001). However, the phospholipids of the stroke patients had significantly higher percentages of 20-, 22-, and 24-carbon saturated fatty acids, as well as higher proportions of the omega-6 fatty-acid, arachidonic acid (11.4 versus 8.14%, p < 0.001), and the omega-3 fatty-acid, docosahexaenoic acid (3.21 versus 1.80%, p < 0.001). Using the percentages and melting points of the individual fatty acids, we estimated that the acyl chains of the serum phospholipids of the stroke patients had a lower mean melting point than the controls (27.8 versus 34.6 degrees C, p < 0.001). Assuming that serum phospholipids are surrogates for tissue phospholipids, we conclude that the tissue membranes of the stroke patients may be considerably more fluid than those of the controls.

Effect of lavender essential oil on LPS-stimulated inflammation.

Lavender essential oil (LEO) is one the most favorite and widely used essential oils in aromatherapy. Many studies have demonstrated its functions in calming, assisting sleep, reducing pain and muscular spasms and its antiseptic function. To date, however, the mechanism of LEO on inflammation response is not well understood. In this study, we examined the effect of LEO on 5 µg/ml lipopolysaccharide (LPS) induced inflammation reaction in human monocyte THP-1 cells. We found treatment of 0.1% LEO significantly increased cell viability and inhibited the IL-1ß and superoxide anion generation in LPS-stimulated THP-1 cells. Treatment with LEO down-regulated both LPS-induced protein levels of phospho-NF-κB and membrane Toll-like receptor 4. To determine whether the chaperone protein was involved in the reaction, we determined the levels of Heat Shock Protein 70 (HSP70). Our results showed that LEO increased HSP70 expression in LPS-stimulated THP-1 cells, suggesting that the LEO inhibited LPS-induced inflammatory effect might be associated with the expression of HSP70.

Co-expression of heterologous desaturase genes in Yarrowia lipolytica.

The hybrid promoter (hp4d) expression cassette, one of the efficient tools of Yarrowia lipolytica expression system, has been applied to produce or secrete a variety of recombinant proteins. This cassette directs a strong gene expression, because the hp4d promoter exhibits high level quasi-constitutive activity. The objective of this study is to test whether two expression cassettes inserted into a vector could function efficiently and simultaneously. Taking advantage of the well-known biosynthesis pathway of gamma-linolenic acid (GLA), we examined the performance of Y. lipolytica, transformed with two expression cassettes containing previously cloned Delta12-desaturase and Delta6-desaturase genes, by monitoring fatty acid composition of cellular lipids. Our results confirmed that each individual desaturase gene was expressed efficiently by the expression cassette. When two cassettes with respective desaturase genes, carried on the same vector, were integrated into yeast genome, a significant level of GLA was synthesized from endogenous linoleic acid (LA) and oleic acid (OA). Besides, both expression cassettes functioned effectively without influence from each other. These findings indicated that co-expression of two desaturase genes by this dual cassette vector was effective and simultaneous. Results from the present study provide an alternative approach for both the production of several proteins at the same time, and the development of single cell oil containing high-valued polyunsaturated fatty acids (PUFAs).

Uptake and incorporation of pinolenic acid reduces n-6 polyunsaturated fatty acid and downstream prostaglandin formation in murine macrophage.

Many reports have shown the beneficial effects of consumption of pine seeds and pine seed oil. However, few studies have examined the biological effect of pinolenic acid (PNA; 5,9,12-18:3), the main fatty acid in pine seed oil. In this study, using murine macrophage RAW264.7 cells as a model, we examined the effect of PNA on polyunsaturated fatty acid (PUFA) metabolism, prostaglandin (PG) biosynthesis and cyclooxygenase-2 (COX-2) expression. Results showed that PNA was readily taken up, incorporated and elongated to form eicosatrienoic acid (ETrA, 7,11,14-20:3) in macrophage cells. A small portion of this elongated metabolite was further elongated to form 9,13,16-22:3. The degree of incorporation of PNA and its metabolites into cellular phospholipids varied with the length of incubation time and the concentration of PNA in the medium. Incubation of PNA also modified the fatty acid profile of phospholipids: the levels of 18- and 20-carbon PUFA were significantly decreased, whereas those of 22-carbon fatty acids increased. This finding suggests that PNA enhances the elongation of 20-carbon fatty acids to 22-carbon fatty acids. The syntheses of PGE(1) from dihomo-gamma-linolenic acid (DGLA, 8,11,14-20:4) and PGE(2) from arachidonic acid (ARA, 5,8,11,14-20:4) were also suppressed by the presence of PNA and its metabolite. As the expression of COX-2 was not suppressed, the inhibitory effect of PNA on PG activity was attributed in part to substrate competition between the PNA metabolite (i.e., 7,11,14-20:3) and DGLA (or ARA).

Inhibition of proliferation of a hepatoma cell line by fucoxanthin in relation to cell cycle arrest and enhanced gap junctional intercellular communication.

Fucoxanthin is one of the most abundant carotenoids found in Undaria pinnatifida and has been shown to inhibit tumor proliferation in vitro. However, the mechanisms underlying the anti-cancer effects of fucoxanthin are unclear. In this study, we hypothesized that fucoxanthin may cause cell cycle arrest and enhance gap junctional intercellular communication (GJIC) in SK-Hep-1 human hepatoma cells. Data revealed that fucoxanthin (1-20microM) strongly and concentration-dependently inhibited the proliferation of SK-Hep-1 cells at 24h of incubation, whereas fucoxanthin facilitated the growth of a murine embryonic hepatic (BNL CL.2) cells at 24h of incubation and only slightly slowed the cell proliferation at 48h. In SK-Hep-1 cells, fucoxanthin caused cell cycle arrest at G0/G1 phase and induced cell apoptosis, as evidenced by increased subG1 cells and induction of DNA strand breaks. Using scrape loading-dye-transfer assay, fucoxanthin was found to significantly enhance GJIC of SK-Hep-1 cells without affecting that of BNL CL.2 cells. In addition, fucoxanthin significantly increased protein and mRNA expressions of connexin 43 (Cx43) and connexin 32 (Cx32) in SK-Hep-1 cells. Moreover, fucoxanthin markedly increased the concentration of intracellular calcium levels in SK-Hep-1 cells. Thus, fucoxanthin is specifically antiproliferative against SK-Hep-1 cells, and the effect is associated with upregulation of Cx32 and Cx43, which enhances GJIC of SK-Hep-1 cells. The enhanced GJIC may be responsible for the increase of the intracellular calcium level, which then causes cell cycle arrest and apoptosis.