Increasing palmitic acid and reducing stearic acid content of supplemental fatty acid blends improves production performance of mid-lactation dairy cows

We determined the effects of altering the ratio of palmitic (C16:0) and stearic (C18:0) acids in supplemental fatty acid (FA) blends on production responses of mid-lactation dairy cows. Twenty-four multiparous Holstein cows (mean ± standard deviation; 47.1 ± 5.8 kg of milk yield, 109 ± 23 DIM) were randomly assigned to treatment sequences in a replicated 4 × 4 Latin square design with 21-d periods. Treatments were a control diet not supplemented with FA (CON), and 3 diets incorporating 1.5% of dry matter (DM) FA supplement blends containing 30% C16:0 + 50% C18:0, 50% C16:0 + 30% C18:0, and 80% C16:0 + 10% C18:0. Additionally, the FA blends were balanced to contain 10% of oleic acid (cis-9 C18:1). The FA blends replaced soyhulls in the CON diet. Diets were formulated to contain (% of DM) 31.0% neutral detergent fiber, 27.0% starch, and 16.9% crude protein. The statistical model included the random effect of cow within square and the fixed effects of period, treatment, and their interaction. Preplanned contrasts included CON versus overall effect of FA supplementation and the linear and quadratic effects of increasing C16:0 in FA blends. Overall FA treatment had no effect on dry matter intake (DMI), but increasing C16:0 linearly increased DMI. Compared with CON, overall FA treatment increased yields of milk, 3.5% of fat-corrected milk, energy-corrected milk, and milk fat but did not affect milk protein yield. Increasing C16:0 linearly increased milk fat yield and tended to linearly increase the yields of 3.5% of fat-corrected milk and energy-corrected milk. Fatty acid supplementation decreased the yield of de novo milk FA but increased yields of mixed and preformed milk FA compared with CON. Increasing C16:0 in FA treatments did not affect the yield of de novo milk FA, linearly increased the yield of mixed, and decreased the yield of preformed milk FA. In summary, feeding FA supplements containing C16:0 and C18:0 increased milk production responses with no effect on DMI compared with a control diet. Mid-lactation cows producing ∼40 to 50 kg/d milk yield responded best to increasing supplemental C16:0 in FA supplements, demonstrating that FA supplements higher in C16:0 and limited in C18:0 improves production responses.

Stearic acid promotes lipid synthesis through CD36/Fyn/FAK/mTORC1 axis in bovine mammary epithelial cells

Stearic acid (C18:0, SA) is a saturated long-chain fatty acid (LCFA) that has a prominent function in lactating dairy cows. It is obtained primarily from the diet and is stored in the form of triacylglycerol (TAG) molecules. The transmembrane glycoprotein cluster of differentiation 36 (CD36) is also known as fatty acid translocase, but whether SA promotes lipid synthesis through CD36 and FAK/mTORC1 signaling is unknown. In this study, we examined the function and mechanism of CD36-mediated SA-induced lipid synthesis in bovine mammary epithelial cells (BMECs). SA-enriched supplements enhanced lipid synthesis and the FAK/mTORC1 pathway in BMECs. SA-induced lipid synthesis, FAK/mTORC1 signaling, and the expression of lipogenic genes were impaired by anti-CD36 and the CD36-specific inhibitor SSO, whereas overexpression of CD36 effected the opposite results. Inhibition of FAK/mTORC1 by TAE226/Rapamycin attenuated SA-induced TAG synthesis, inactivated FAK/mTORC1 signaling, and downregulated the lipogenic genes PPARG, CD36, ACSL1, SCD, GPAT4, LIPIN1, and DGAT1 at the mRNA and protein levels in BMECs. By coimmunoprecipitation and yeast two-hybrid screen, CD36 interacted directly with Fyn but not Lyn, and Fyn bound directly to FAK; FAK also interacted directly with TSC2. CD36 linked FAK through Fyn, and FAK coupled mTORC1 through TSC2 to form the CD36/Fyn/FAK/mTORC1 signaling axis. Thus, stearic acid promotes lipogenesis through CD36 and Fyn/FAK/mTORC1 signaling in BMECs. Our findings provide novel insights into the underlying molecular mechanisms by which LCFA supplements promote lipid synthesis in BMECs.

Effects of inoculation with four mycorrhizal species on seed phenolic and fatty acids of sesame plants grown under different irrigation regimes

This study evaluated the interaction effects of irrigation level (well-watered and water stress conditions) and inoculation by different mycorrhizal species (non-inoculated, Funneliformis mosseae, Rhizophagus irregularis, Claroideoglomus claroideum, and Glomus fasciculatum) on mycorrhizal colonization, antioxidant activity, seed yield and oil quality of two sesame cultivars (Yekta and Naz). Water deficit decreased mycorrhizal colonization, seed yield and oil concentration but increased antioxidant activity and seed total phenol and flavonoid concentrations. However, mycorrhizal inoculation increased antioxidant activity, seed yield, oil concentration and total phenolic and flavonoids. The lowest reduction by water stress and the highest increase by inoculation in seed yield were observed in Naz plants inoculated by Cl. claroideum. Principal component analysis showed the highest differentiation effect of water stress compared to mycorrhizal inoculation on both cultivars, indicating the relative sensitivity of the two cultivars to water deficit. However, the application of different species of mycorrhizal fungi versus the non-inoculation conditions was somewhat discriminative. In terms of fatty acids, in most cases, water stress increased oleic, palmitic and stearic acids and decreased linoleic and linolenic acids but inoculation increased oleic and linoleic acids and decreased linolenic, palmitic and stearic acids. Regarding phenolic and flavonoids components, the contents of chlorogenic and caffeic acids were increased by water stress but no consistent trend was noted in response to water stress for the other compounds. Mycorrhizal inoculation generally decreased chlorogenic acid but increased gallic, caffeic, p-coumaric, and ferulic acids. In conclusion, the results of the present study may help to increase the level of valuable compounds in sesame for further pharmaceutical purposes under water stress conditions and mycorrhizal symbiosis.

Altering palmitic acid and stearic acid ratios in the diet of early-lactation Holsteins under heat stress: Feed intake, digestibility, feeding behavior, milk yield and composition, and plasma metabolites

The objective of this study was to evaluate the effects of varying the ratio of dietary palmitic (C16:0; PA) and stearic (C18:0; SA) acids on nutrient digestibility, production, and blood metabolites of early-lactation Holsteins under mild-to-moderate heat stress. Eight multiparous Holsteins (body weight = 589 ± 45 kg; days in milk = 51 ± 8 d; milk production = 38.5 ± 2.4 kg/d; mean ± standard deviation) were used in a duplicated 4 × 4 Latin square design (21-d periods inclusive of 7-d data collection). The PA (88.9%)- and SA (88.5%)-enriched fat supplements, either individually or in combination, were added to diets at 2% of dry matter (DM) to formulate the following treatments: (1) 100PA:0SA (100% PA + 0% SA), (2) 66PA:34SA (66% PA + 34% SA), (3) 34PA:66SA (34% PA + 66% SA), and (4) 0PA:100SA (0% PA + 100% SA). Diets offered, in the form of total mixed rations, were formulated to be isonitrogenous (crude protein = 17.2% of DM) and isocaloric (net energy for lactation = 1.69 Mcal/kg DM), with a forage-to-concentrate ratio of 40:60. Ambient temperature-humidity index averaged 72.9 throughout the experiment, suggesting that cows were under mild-to-moderate heat stress. No differences in DM intake across treatments were detected (mean 23.5 ± 0.64 kg/d). Increasing the dietary proportion of SA resulted in a linear decrease in total-tract digestibility of total fatty acids, but organic matter, DM, neutral detergent fiber, and crude protein digestibilities were not different across treatments. Decreasing dietary PA-to-SA had no effect on the time spent eating (340 min/d), rumination (460 min/d), and chewing (808 min/d). As dietary PA-to-SA decreased, milk fat concentration and yield decreased linearly, resulting in a linear decrease of 3.5% fat-corrected milk production and milk fat-to-protein ratio. Feed efficiency expressed as kg 3.5% fat-corrected milk/kg DM intake decreased linearly with decreasing the proportion of PA-to-SA in the diet. Treatments had no effect on milk protein and lactose content. A linear increase in de novo and preformed fatty acids was identified as the ratio of PA to SA decreased, while PA and SA concentrations of milk fat decreased and increased linearly, respectively. A linear reduction in blood nonesterified fatty acids and glucose was detected as the ratio of PA to SA decreased. Insulin concentration increased linearly from 10.3 in 100PA:0SA to 13.1 µIU/mL in 0PA:100SA, whereas blood β-hydroxybutyric acid was not different across treatments. In conclusion, the heat-stressed Holsteins in early-lactation phase fed diets richer in PA versus SA produced greater fat-corrected milk and were more efficient in converting feed to fat-corrected milk.

Overexpression of miR-297b-5p in Mouse Insulin-Secreting Cells Promotes Metformin-Mediated Protection Against Stearic Acid-Induced Senescence by Targeting Igf1r

BACKGROUND

A long-term consumption of saturated fat significantly increases the concentration of saturated fatty acids in serum, which accelerates the appearance of senescence markers in β-cells and leads to their dysfunction. An understanding of the mechanisms underlying β-cell senescence induced by stearic acid and the exploration of effective agents preventing it remains largely unclear. Here, we aimed to investigate the protective effect of metformin against stearic acid-treated β-cell senescence and to assess the involvement of miR-297b-5p in this process.

METHODS

To identify senescence, we measured senescence-associated β-galactosidase activity and the expression of senescence-related genes. Gain and loss of function approaches were applied to explore the role of miR-297b-5p in stearic acid-induced β-cell senescence. Bioinformatics analysis and a luciferase activity assay were used to predict the downstream targets of miR-297b-5p.

RESULTS

Stearic acid markedly induced senescence and suppressed miR-297b-5p expression in mouse β-TC6 cells, which were significantly alleviated by metformin. After transfection of miR-297b-5p mimics, stearic acid-evoked β-cell senescence was remarkably prevented. Insulin-like growth factor-1 receptor was identified as a direct target of miR-297b-5p. Inhibition of the insulin-like growth factor-1 receptor prevented stearic acid-induced β-cell senescence and dysfunction. Moreover, metformin alleviates the impairment of the miR-297b-5p inhibitor in β-TC6 cells. Additionally, long-term consumption of a high-stearic-acid diet significantly increased senescence and reduced miR-297b-5p expression in mouse islets.

CONCLUSIONS

These findings imply that metformin alleviates β-cell senescence by stearic acid through upregulating miR-297b-5p to suppress insulin-like growth factor-1 receptor expression, thereby providing a potential target to not only prevent high fat-diet-induced β-cell dysfunction but also for metformin therapy in type 2 diabetes.

Inhibition of miR-146a-5p and miR-8114 in Insulin-Secreting Cells Contributes to the Protection of Melatonin against Stearic Acid-Induced Cellular Senescence by Targeting Mafa

BACKGRUOUND

Chronic exposure to elevated levels of saturated fatty acids results in pancreatic β-cell senescence. However, targets and effective agents for preventing stearic acid-induced β-cell senescence are still lacking. Although melatonin administration can protect β-cells against lipotoxicity through anti-senescence processes, the precise underlying mechanisms still need to be explored. Therefore, we investigated the anti-senescence effect of melatonin on stearic acid-treated mouse β-cells and elucidated the possible role of microRNAs in this process.

METHODS

β-Cell senescence was identified by measuring the expression of senescence-related genes and senescence-associated β-galactosidase staining. Gain- and loss-of-function approaches were used to investigate the involvement of microRNAs in stearic acid-evoked β-cell senescence and dysfunction. Bioinformatics analyses and luciferase reporter activity assays were applied to predict the direct targets of microRNAs.

RESULTS

Long-term exposure to a high concentration of stearic acid-induced senescence and upregulated miR-146a-5p and miR- 8114 expression in both mouse islets and β-TC6 cell lines. Melatonin effectively suppressed this process and reduced the levels of these two miRNAs. A remarkable reversibility of stearic acid-induced β-cell senescence and dysfunction was observed after silencing miR-146a-5p and miR-8114. Moreover, V-maf musculoaponeurotic fibrosarcoma oncogene homolog A (Mafa) was verified as a direct target of miR-146a-5p and miR-8114. Melatonin also significantly ameliorated senescence and dysfunction in miR-146a-5pand miR-8114-transfected β-cells.

CONCLUSION

These data demonstrate that melatonin protects against stearic acid-induced β-cell senescence by inhibiting miR-146a- 5p and miR-8114 and upregulating Mafa expression. This not only provides novel targets for preventing stearic acid-induced β-cell dysfunction, but also points to melatonin as a promising drug to combat type 2 diabetes progression.

Palmitic and Stearic Acids Inhibit Chaperone-Mediated Autophagy (CMA) in POMC-like Neurons In Vitro

The intake of food with high levels of saturated fatty acids (SatFAs) is associated with the development of obesity and insulin resistance. SatFAs, such as palmitic (PA) and stearic (SA) acids, have been shown to accumulate in the hypothalamus, causing several pathological consequences. Autophagy is a lysosomal-degrading pathway that can be divided into macroautophagy, microautophagy, and chaperone-mediated autophagy (CMA). Previous studies showed that PA impairs macroautophagy function and insulin response in hypothalamic proopiomelanocortin (POMC) neurons. Here, we show in vitro that the exposure of POMC neurons to PA or SA also inhibits CMA, possibly by decreasing the total and lysosomal LAMP2A protein levels. Proteomics of lysosomes from PA- and SA-treated cells showed that the inhibition of CMA could impact vesicle formation and trafficking, mitochondrial components, and insulin response, among others. Finally, we show that CMA activity is important for regulating the insulin response in POMC hypothalamic neurons. These in vitro results demonstrate that CMA is inhibited by PA and SA in POMC-like neurons, giving an overview of the CMA-dependent cellular pathways that could be affected by such inhibition and opening a door for in vivo studies of CMA in the context of the hypothalamus and obesity.

Exploring the effect of estrogen on Candida albicans hyphal cell wall glycans and ergosterol synthesis

Increased levels of 17-β estradiol (E2) due to pregnancy in young women or to hormonal replacement therapy in postmenopausal women have long been associated with an increased risk of yeast infections. Nevertheless, the effect underlying the role of E2 in Candida albicans infections is not well understood. To address this issue, functional, transcriptomic, and metabolomic analyses were performed on C. albicans cells subjected to temperature and serum induction in the presence or absence of E2. Increased filament formation was observed in E2 treated cells. Surprisingly, cells treated with a combination of E2 and serum showed decreased filament formation. Furthermore, the transcriptomic analysis revealed that serum and E2 treatment is associated with downregulated expression of genes involved in filamentation, including HWP1, ECE1, IHD1, MEP1, SOD5, and ALS3, in comparison with cells treated with serum or estrogen alone. Moreover, glucose transporter genes HGT20 and GCV2 were downregulated in cells receiving both serum and E2. Functional pathway enrichment analysis of the differentially expressed genes (DEGs) suggested major involvement of E2 signaling in several metabolic pathways and the biosynthesis of secondary metabolites. The metabolomic analysis determined differential secretion of 36 metabolites based on the different treatments' conditions, including structural carbohydrates and fatty acids important for hyphal cell wall formation such as arabinonic acid, organicsugar acids, oleic acid, octadecanoic acid, 2-keto-D-gluconic acid, palmitic acid, and steriacstearic acid with an intriguing negative correlation between D-turanose and ergosterol under E2 treatment. In conclusion, these findings suggest that E2 signaling impacts the expression of several genes and the secretion of several metabolites that help regulate C. albicans morphogenesis and virulence.

Nanostructured Lipid Carriers Can Enhance Oral Absorption of Khellin, a Natural Pleiotropic Molecule

A novel formulation based on nanostructured lipid carriers (NLCs) was developed to increase solubility and intestinal absorption of khellin. K-NLCs were prepared with stearic acid, hempseed oil, Brij S20, and Labrafil M 1944 CS, using the emulsification-ultrasonication method. Developed nanoparticles were chemically and physically characterized by liquid chromatography, light scattering techniques, and electron microscopy. The size, about 200 nm, was optimal for oral delivery, and the polydispersity index (around 0.26), indicated high sample homogeneity. Additionally, K-NLCs showed a spherical morphology without aggregation by microscopic analysis. The encapsulation efficiency of khellin was about 55%. In vitro release studies were carried out in media with different pH to mimic physiological conditions. K-NLCs were found to be physically stable in the simulated gastric and intestinal fluids, and they preserved about 70% of khellin after 6 h incubation. K-NLCs were also successfully lyophilized testing different lyoprotectants, and obtained freeze-dried K-NLCs demonstrated good shelf life over a month. Lastly, permeability studies on Caco-2 cells were performed to predict khellin passive diffusion across the intestinal epithelium, demonstrating that nanoparticles increased khellin permeability by more than two orders of magnitude. Accordingly, developed NLCs loaded with khellin represent a versatile formulation with good biopharmaceutical properties for oral administration, possibly enhancing khellin's bioavailability and therapeutic effects.

Inhibition of lncRNA TCONS_00077866 Ameliorates the High Stearic Acid Diet-Induced Mouse Pancreatic β-Cell Inflammatory Response by Increasing miR-297b-5p to Downregulate SAA3 Expression

Long-term consumption of a high-fat diet increases the circulating concentration of stearic acid (SA), which has a potent toxic effect on β-cells, but the underlying molecular mechanisms of this action have not been fully elucidated. Here, we evaluated the role of long noncoding (lnc)RNA TCONS_00077866 (lnc866) in SA-induced β-cell inflammation. lnc866 was selected for study because lncRNA high-throughput sequencing analysis demonstrated it to have the largest fold-difference in expression of five lncRNAs that were affected by SA treatment. Knockdown of lnc866 by virus-mediated shRNA expression in mice or by Smart Silencer in mouse pancreatic β-TC6 cells significantly inhibited the SA-induced reduction in insulin secretion and β-cell inflammation. According to lncRNA-miRNAs-mRNA coexpression network analysis and luciferase reporter assays, lnc866 directly bound to miR-297b-5p, thereby preventing it from reducing the expression of its target serum amyloid A3 (SAA3). Furthermore, overexpression of miR-297b-5p or inhibition of SAA3 also had marked protective effects against the deleterious effects of SA in β-TC6 cells and mouse islets. In conclusion, lnc866 silencing ameliorates SA-induced β-cell inflammation by targeting the miR-297b-5p/SAA3 axis. lnc866 inhibition may represent a new strategy to protect β-cells against the effects of SA during the development of type 2 diabetes.

9-PAHSA Prevents Mitochondrial Dysfunction and Increases the Viability of Steatotic Hepatocytes

Nonalcoholic fatty liver disease (NAFLD) is quickly becoming the most common liver disease worldwide. Within the NAFLD spectrum, patients with nonalcoholic steatohepatitis (NASH) are at the highest risk of developing cirrhosis and disease progression to hepatocellular carcinoma. To date, therapeutic options for NASH patients have been ineffective, and therefore, new options are urgently needed. Hence, a model system to develop new therapeutic interventions is needed. Here, we introduce two new in vitro models of steatosis induction in HepG2 cells and primary murine hepatocytes. We used a recently discovered novel class of bioactive anti-inflammatory lipids called branched fatty acid esters of hydroxyl fatty acids. Among these bioactive lipids, palmitic-acid-9-hydroxy-stearic-acid (9-PAHSA) is the most promising as a representative nondrug therapy based on dietary supplements or nutritional modifications. In this study, we show a therapeutic effect of 9-PAHSA on lipotoxicity in steatotic primary hepatocytes and HepG2 cells. This could be shown be increased viability and decreased steatosis. Furthermore, we could demonstrate a preventive effect in HepG2 cells. The outcome of 9-PAHSA administration is both preventative and therapeutically effective for hepatocytes with limited damage. In conclusion, bioactive lipids like 9-PAHSA offer new hope for prevention or treatment in patients with fatty liver and steatosis.

Stearic acid methyl ester affords neuroprotection and improves functional outcomes after cardiac arrest

Cardiac arrest causes neuronal damage and functional impairments that can result in learning/memory dysfunction after ischemia. We previously identified a saturated fatty acid (stearic acid methyl ester, SAME) that was released from the superior cervical ganglion (sympathetic ganglion). The function of stearic acid methyl ester is currently unknown. Here, we show that SAME can inhibit the detrimental effects of global cerebral ischemia (i.e. cardiac arrest). Treatment with SAME in the presence of asphyxial cardiac arrest (ACA) revived learning and working memory deficits. Similarly, SAME-treated hippocampal slices after oxygen-glucose deprivation inhibited neuronal cell death. Moreover, SAME afforded neuroprotection against ACA in the CA1 region of the hippocampus, reduced ionized calcium-binding adapter molecule 1 expression and inflammatory cytokines/chemokines, with restoration in mitochondria respiration. Altogether, we describe a unique and uncharted role of saturated fatty acids in the brain that may have important implications against cerebral ischemia.

miRNA-mRNA profile and regulatory network in stearic acid-treated β-cell dysfunction

Chronic exposure of pancreatic β-cells to saturated fatty acid (palmitic or stearic acid) is a leading cause of impaired insulin secretion. However, the molecular mechanisms underlying stearic-acid-induced β-cell dysfunction remain poorly understood. Emerging evidence indicates that miRNAs are involved in various biological functions. The aim of this study was to explore the differential expression of miRNAs and mRNAs, specifically in stearic-acid-treated- relative to palmitic-acid-treated β-cells, and to establish their co-expression networks. β-TC-6 cells were treated with stearic acid, palmitic acid or normal medium for 24 h. Differentially expressed miRNAs and mRNAs were identified by high-throughput sequencing and bioinformatic analysis. Co-expression network, gene ontology (GO) and pathway analyses were then conducted. Changes in the expression of selected miRNAs and mRNAs were verified in β-TC-6 cells and mouse islets. Sequencing analysis detected 656 known and 1729 novel miRNAs. miRNA-mRNA network and Venn-diagram analysis yielded two differentially expressed miRNAs and 63 mRNAs exclusively in the stearic-acid group. miR-374c-5p was up-regulated by a 1.801 log2(fold-change) and miR-297b-5p was down-regulated by a -4.669 log2(fold-change). We found that miR-297b-5p and miR-374c-5p were involved in stearic-acid-induced lipotoxicity to β-TC-6 cells. Moreover, the effects of miR-297b-5p and miR-374c-5p on the alterations of candidate mRNAs expressions were verified. This study indicates that expression changes of specific miRNAs and mRNAs may contribute to stearic-acid-induced β-cell dysfunction, which provides a preliminary basis for further functional and molecular mechanism studies of stearic-acid-induced β-cell dysfunction in the development of type 2 diabetes.

Serotonin-Stearic Acid Bioconjugate-Coated Completely Biodegradable Mn3O4 Nanocuboids for Hepatocellular Carcinoma Targeting

In this study, a serotonin-stearic acid (ST-SA)-based bioconjugate was synthesized for the surface modification of manganese oxide-based nanocuboids (MNCs) for delivering of anticancer drug (i.e., doxorubicin hydrochloride (DOX)) to human liver cancer cells. MNCs were synthesized by chemical precipitation method, and their surface was modified with ST-SA bioconjugate for targeting of MNCs to cancer cells. The ST-SA@MNCs along with DOX showed good colloidal stability, high drug encapsulation (98.3%), and drug loading efficiencies (22.9%) as well as pH-responsive biodegradation. Coating with ST-SA conjugate provided a shield to MNCs which sustained their degradation in an acidic environment. The release of DOX was higher (81.4%) in acidic media than under the physiological conditions (20.5%) up to 192 h. The in vitro anti-proliferation assay showed that ST-SA@MNCs exhibit higher cell growth inhibition compared to that of pure DOX after 48 h of treatment. The cellular uptake and apoptosis studies revealed the enhanced uptake of ST-SA@MNCs in contrast to the MNCs due to overexpressed ST receptor on hepatocellular carcinoma cells and triggered the generation of reactive oxygen species in the cells. Therefore, these results indicated that the DOX-loaded, ST-SA stabilized MNCs improved the therapeutic index of DOX and would be a promising therapeutic candidate for tumor therapy.

Overexpression of miR-297b-5p protects against stearic acid-induced pancreatic β-cell apoptosis by targeting LATS2

Chronic exposure to high concentrations of stearic acid (C18:0) can result in β-cell dysfunction, leading to development of type 2 diabetes. However, the molecular mechanisms underlying the destructive effects of stearic acid on β-cells remain largely unknown. In this study, we aimed to investigate the role of miR-297b-5p on stearic acid-induced β-cell apoptosis. Differential expression of microRNAs (miRNAs) was assessed in a β-TC6 cell line exposed to stearic acid, palmitic acid, or a normal culture medium by high-throughput sequencing. The apoptosis rate was measured by flow cytometry after miR-297b-5p mimic/inhibitor transfection, and large-tumor suppressor kinase 2 (LATS2) was identified as a target of miR-297b-5p using a luciferase activity assay. In vivo, C57BL/6 mice were fed with normal and high-stearic-acid diet, respectively. Mouse islets were used for similar identification of miR-297b-5p and Lats2 in β-TC6 cell. We selected two differentially expressed miRNAs in stearic acid compared with those in the palmitic acid and control groups. miR-297b-5p expression was significantly lower in β-TC6 cells and mouse islets in stearic acid than in control group. Upregulation of miR-297b-5p alleviated the stearic acid-induced cell apoptosis and reduction in insulin secretion by inhibiting Lats2 expression in vitro. Meanwhile, silencing Lats2 significantly reversed the stearic acid-stimulated β-cell dysfunction in both β-TC6 cells and islets. Our findings indicate a suppressive role for miR-297b-5p in stearic acid-induced β-cell apoptosis, which may reveal a potential target for the treatment of β-cell dysfunction in the pathogenesis of type 2 diabetes.

Encapsulation of Variabilin in Stearic Acid Solid Lipid Nanoparticles Enhances Its Anticancer Activity in Vitro

The use of natural products as chemotherapeutic agents is well established; however, many of these are associated with undesirable side effects, including high toxicity and instability. Furthermore, the development of drug resistant cancers makes the search for new anticancer lead compounds a priority. In this study, the extraction of an Ircinia sp. sponge resulted in the isolation of an inseparable mixture of (7E,12E,20Z)-variabilin (1) and (7E,12Z,20Z)-variabilin (2) and structural assignment was established using standard 1D and 2D NMR experiments. The cytotoxic activity of the compound against three solid tumour cell lines displayed moderate anti-cancer activity through apoptosis, together with a general lack of selectivity among the cancer cell lines studied. Structural assignment and cytotoxic evaluation of variabilin was complicated and further aggravated by its inherent instability. Variabilin was therefore incorporated into solid lipid nanoparticles (SLNs) and the stability and cytotoxic activity evaluated. Encapsulation of variabilin into SLNs led to a marked improvement in stability of the natural product coupled with enhanced cytotoxic activity, particularly against the prostate (PC-3) cancer cell line, with IC50 values of 87.74 μM vs. 8.94 μM for the variabilin alone and Var-SLN, respectively. Both variabilin and Var-SLN revealed comparable activity to Ceramide against the MCF-7 breast cancer cell line, revealing IC50 values of 34.8, 38.1 and 33.6 μM for variabilin, Var-SLN and Ceramide, respectively. These samples revealed no activity (>100 μM for all) against HT-29 (colon) cell lines and MCF-12 (normal breast) cell lines. Var-SLNs induced 47, 48 and 59% of apoptosis in HT-29, MCF-7 and PC-3 cells, respectively, while variabilin alone revealed 38, 29 and 29% apoptotic cells for HT-29, MCF-7 and PC-3 cell lines, respectively. The encapsulation of natural products into SLNs may provide a promising approach to overcome some of the issues hindering the development of new anticancer drugs from natural products.

Different Effects of Nicotine and N-Stearoyl-ethanolamine on Episodic Memory and Brain Mitochondria of α7 Nicotinic Acetylcholine Receptor Knockout Mice

Nicotinic acetylcholine receptors of α7 subtype (α7 nAChRs) are involved in regulating neuroinflammation and cognitive functions. Correspondingly, α7-/- mice demonstrate pro-inflammatory phenotype and impaired episodic memory. In addition, nAChRs expressed in mitochondria regulate the release of pro-apoptotic factors like cytochrome c. Here we studied whether the cognitive deficiency of α7-/- mice can be cured by oral consumption of either nicotine or N-stearoylethanolamine (NSE), a lipid possessing anti-inflammatory, cannabimimetic and membrane-stabilizing activity. Mice were examined in Novel Object Recognition behavioral test, their blood, brains and brain mitochondria were tested for the levels of interleukin-6, various nAChR subtypes and cytochrome c released by ELISA. The data presented demonstrate that both substances stimulated the raise of interleukin-6 in the blood and improved episodic memory of α7-/- mice. However, NSE improved, while nicotine worsened the brain mitochondria sustainability to apoptogenic stimuli, as shown by either decreased or increased amounts of cytochrome c released. Both nicotine and NSE up-regulated α4β2 nAChRs in the brain; NSE up-regulated, while nicotine down-regulated α9-containing nAChRs in the brain mitochondria. It is concluded that the level of alternative nAChR subtypes in the brain is critically important for memory and mitochondria sustainability in the absence of α7 nAChRs.

PAHSAs attenuate immune responses and promote β cell survival in autoimmune diabetic mice

Palmitic acid esters of hydroxy stearic acids (PAHSAs) are endogenous antidiabetic and antiinflammatory lipids. Here, we show that PAHSAs protect against type 1 diabetes (T1D) and promote β cell survival and function. Daily oral PAHSA administration to nonobese diabetic (NOD) mice delayed the onset of T1D and markedly reduced the incidence of T1D, whether PAHSAs were started before or after insulitis was established. PAHSAs reduced T and B cell infiltration and CD4+ and CD8+ T cell activation, while increasing Treg activation in pancreata of NOD mice. PAHSAs promoted β cell proliferation in both NOD mice and MIN6 cells and increased the number of β cells in NOD mice. PAHSAs attenuated cytokine-induced apoptotic and necrotic β cell death and increased β cell viability. The mechanism appears to involve a reduction of ER stress and MAPK signaling, since PAHSAs lowered ER stress in NOD mice, suppressed thapsigargin-induced PARP cleavage in human islets, and attenuated ERK1/2 and JNK1/2 activation in MIN6 cells. This appeared to be mediated in part by glucagon-like peptide 1 receptor (GLP-1R) and not the G protein-coupled receptor GPR40. PAHSAs also prevented impairment of glucose-stimulated insulin secretion and improved glucose tolerance in NOD mice. Thus, PAHSAs delayed the onset of T1D and reduced its incidence by attenuating immune responses and exerting direct protective effects on β cell survival and function.

Bio-derived hydroxystearic acid ameliorates skin age spots and conspicuous pores

INTRODUCTION

We report on the preparation and efficacy of 10-hydroxystearic acid (HSA) that improves facial age spots and conspicuous pores.

METHODS

The hydration of oleic acid into HSA was catalyzed by the oleate hydratase from Escherichia coli. Following treatment with HSA, collagen type I and type III was assessed in primary human dermal fibroblasts together with collagen type III, p53 protein levels and sunburn cells (SBC) after UVB irradiation (1 J cm^-2 ) by immunohistochemistry on human ex vivo skin. UVB-induced expression of matrix metalloprotease-1 (MMP-1) was determined from full thickness skin by RT-qPCR. Modification of the fibroblast secretome by HSA was studied by mass-spectrometry-based proteomics. In a full-face, double blind, vehicle-controlled trial HSA was assessed for its effects on conspicuous facial pore size and degree of pigmentation of age spots in Caucasian women over an 8-week period.

RESULTS

HSA was obtained in enantiomeric pure, high yield (≥80%). Collagen type I and type III levels were dose-dependently increased (96% and 244%; P < 0.01) in vitro and collagen type III in ex vivo skin by +57% (P < 0.01) by HSA. HSA also inhibited UVB-induced MMP-1 gene expression (83%; P < 0.01) and mitigated SBC induction (-34% vs. vehicle control) and reduced significantly UV-induced p53 up-regulation (-46% vs. vehicle control; P < 0.01) in irradiated skin. HSA modified the fibroblast secretome with significant increases in proteins associated with the WNT pathway that could reduce melanogenesis and proteins that could modify dermal fibroblast activity and keratinocyte differentiation to account for the alleviation of conspicuous pores. Docking studies in silico and EC50 determination in reporter gene assays (EC50 5.5 × 10^-6  M) identified HSA as a peroxisomal proliferator activated receptor-α (PPARα) agonist. Clinically, HSA showed a statistically significant decrease of surface and volume of skin pores (P < 0.05) after 8 weeks of application and age spots became significantly less pigmented than the surrounding skin (contrast, P < 0.05) after 4 weeks.

CONCLUSION

HSA acts as a PPARα agonist to reduce the signs of age spots and conspicuous pores by significantly modulating the expression of p53, SBC, MMP-1 and collagen together with major changes in secreted proteins that modify keratinocyte, melanocyte and fibroblast cell behavior.

Effects of cationic adjuvant formulation particle type, fluidity and immunomodulators on delivery and immunogenicity of saRNA

Self-amplifying RNA (saRNA) is well suited as a vaccine platform against chlamydia, as it is relatively affordable and scalable, has been shown to induce immunity against multivalent antigens, and can result in protein expression for up to 60 days. Cationic adjuvant formulations (CAFs) have been previously investigated as an adjuvant for protein subunit vaccines; here we optimize the CAFs for delivery of saRNA in vivo and observe the immunogenicity profile in the context of both cellular and humoral immunity against the major outer membrane protein (MOMP) of Chlamydia trachomatis. We tested both liposomal and emulsion based CAFs with solid and fluid phase lipids, with or without the TLR agonists R848 and 3M-052, for in vitro transfection efficiency and cytotoxicity. We then optimized the RNA/delivery system ratio for in vivo delivery using saRNA coding for firefly luciferase (fLuc) as a reporter protein in vivo. We observed that while the fluid phase liposome formulations showed the highest in vitro transfection efficiency, the fluid and solid phase liposomes had equivalent luciferase expression in vivo. Incorporation of R848 or 3M-052 into the formulation was not observed to affect the delivery efficiency of saRNA either in vitro or in vivo. MOMP-encoding saRNA complexed with CAFs resulted in both MOMP-specific cellular and humoral immunity, and while there was a slight enhancement of IFN-γ⁺ T-cell responses when R848 was incorporated into the formulation, the self-adjuvanting effects of RNA appeared to dominate the immune response. These studies establish that CAFs are efficient delivery vehicles for saRNA both for in vitro transfections and in vivo immunogenicity and generate cellular and humoral responses that are proportionate to protein expression.

Acute and Repeated Treatment with 5-PAHSA or 9-PAHSA Isomers Does Not Improve Glucose Control in Mice

Fatty acid esters of hydroxylated fatty acids (FAHFAs) were discovered as a novel class of endogenous mammalian lipids whose profound effects on metabolism have been shown. In the current study, in vitro and in vivo the metabolic effects of two of these FAHFAs, namely palmitic acid-5- (or -9) -hydroxy-stearic acid (5- or 9-PAHSA, respectively) were profiled. In DIO mice fed with differentially composed low- or high-fat diets, acute and subchronic treatment with 5-PAHSA and 9-PAHSA alone, or in combination, did not significantly improve the deranged metabolic status. Neither racemic 5- or 9-PAHSA, nor the enantiomers were able to: (1) increase basal or insulin-stimulated glucose uptake in vitro, (2) stimulate GLP-1 release from GLUTag cells, or (3) induce GSIS in rat, mouse, or human islets or in a human pancreatic β cell line. Therefore, our data do not support the further development of PAHSAs or their derivatives for the control of insulin resistance and hyperglycemia.

[Effects of caprylic acid, capric acid or stearic acid on exogenous cholesterol absorption in intestine of ApoE~(-/-) mice]

OBJECTIVE

To investigate caprylic acid( C8 ∶ 0), capric acid( C10 ∶ 0)or stearic acid( C18∶ 0) on the absorption of exogenous cholesterol in mice.

METHODS

ApoE-/-mice were randomly divided into 3 groups: 2% caprylic acid( C8 ∶ 0), capric acid( C10∶ 0) or stearic acid( C18∶ 0) were fed with high cholesterol diet for 16 weeks. Serum lipids and lipoproteins were measured at the beginning of the experiment, the 8 th week and the 16 th week. At 16 th weeks of intervention, 1 h and 4 h after ~3H-cholesterol intragastric administration, the contents of ~3H-cholesterol in the jejunum, ileum and colon contents of mice were intragastric measured. Also the levels of ~3H-cholesterol in blood of0. 5 h, 1 h, 2 h and 4 h after administration were measured.

RESULTS

Serum TC and LDL-c in the C8∶ 0 group were significantly lower than those in the C18: 0 group at the 8 th week of intervention( P < 0. 01). Serum TC and LDL-c levels of the both C8∶ 0 group and C10∶ 0 group were significantly lower than those in the C18 ∶ 0 group at the 16 th week( P < 0. 01). The contents of ~3H-cholesterol in the jejunum of mice in C8 ∶ 0 group were significantly lower than those in C18 ∶ 0 group after 1 h of ~3H-cholesterol intragastric administration( P < 0. 05). The contents of ~3H-cholesterol in the colon contents of mice in C8∶ 0 group were significantly higher than those in C18∶ 0 group after 1 h( P < 0. 05) and4 h( P < 0. 01) of ~3H-cholesterol intragastric administration. The ~3H-cholesterol content in blood in C8∶ 0 group were significantly lower than those in C18∶ 0 group after 0. 5 h and 2 h of intragastric administration( P < 0. 01). And the area under the curve( AUC) of ~3H-cholesterol in blood after 4 h of intragastric administration in C8∶ 0 group were significantly lower than those in C18 ∶ 0 group( P < 0. 05).

CONCLUSION

Caprylic acid could reduce the absorption of exogenous cholesterol in the intestinal tract and improve blood cholesterol metabolism of mice.

Defense priming by non-jasmonate producing fatty acids in maize (Zea mays)

Previously, we described a priming effect of α-linolenic acid (LnA) on anti-herbivore defense response in maize seedlings. ¹ We showed that exogenous application of LnA stimulated higher jasmonic acid (JA) accumulation and herbivore-induced plant volatile (HIPV) emission after treatment with insect elicitor (IE). To further investigate the specificity of LnA's priming effect, we incubated maize seedlings in palmitoleic acid (PeicA), γ-linolenic acid (γ LnA) and stearic acid (StA) solutions, and analyzed HIPV emission in response to IE. Seedlings incubated in PeicA and γ LnA had 3 and 1.8 times higher HIPV release when compared to controls. In contrast, treatment with StA did not up-regulate HIPV release. We propose that the elevated level and/or the presence of unsaturated fatty acids sensitize the defense signaling system, which in turn augments the defense response of maize when under insect herbivore attack.

Elevated circulating stearic acid leads to a major lipotoxic effect on mouse pancreatic beta cells in hyperlipidaemia via a miR-34a-5p-mediated PERK/p53-dependent pathway

AIMS/HYPOTHESIS

Serum stearic acid (C18:0) is elevated in individuals with hyperlipidaemia and type 2 diabetes. However, the lipotoxicity induced by increased stearic acid in beta cells has not been well described. This study aimed to examine the adverse effects of stearic acid on beta cells and the potential mechanisms through which these are mediated.

METHODS

Three groups of C57BL/6 mice were fed a normal diet or a high-stearic-acid/high-palmitic-acid diet for 24 weeks, respectively. The microRNA (miR) profiles of islets were determined by microarray screening. Islet injury was detected with co-staining using the TUNEL assay and insulin labelling. A lentiviral vector expressing anti-miRNA-34a-5p oligonucleotide (AMO-34a-5p) was injected into mice via an intraductal pancreatic route.

RESULTS

In both mouse islets and cultured rat insulinoma INS-1 cells, stearic acid exhibited a stronger lipotoxic role than other fatty acids, owing to repression of B cell CLL/lymphoma 2 (BCL-2) and BCL-2-like 2 (BCL-W) by stearic acid stimulation of miR-34a-5p. The stearic-acid-induced lipotoxicity and reduction in insulin secretion were alleviated by AMO-34a-5p. Further investigations in INS-1 cells revealed that p53 was involved in stearic-acid-induced elevation of miR-34a-5p, owing in part to activation of protein kinase-like endoplasmic reticulum kinase (PERK). Conversely, silencing PERK alleviated stearic-acid-induced p53, miR-34a-5p and lipotoxicity.

CONCLUSIONS/INTERPRETATION

These findings provide new insight for understanding the molecular mechanisms underlying not only the deleterious impact of stearic-acid-induced lipotoxicity but also apoptosis in beta cells and progression to type 2 diabetes.

Prolongation of the degradation period and improvement of the angiogenesis of zein porous scaffolds in vivo

Zein porous scaffolds modified with fatty acids have shown great improvement in mechanical properties and good cell compatibility in vitro, indicating the potential application as a bone tissue engineering substitute. The present study was conducted to systematically investigate whether the addition of fatty acids affects the short-term (up to 12 weeks) and long-term (up to 1 year) behaviors of scaffolds in vivo, mainly focusing on changes in the degradation period and inflammatory responses. Throughout the implantation period, no abnormal signs occurred and zein porous scaffolds modified with oleic acid showed good tolerance in rabbits, characterized by the growth of relatively more blood vessels in the scaffolds and only a slight degree of fibrosis histology. Moreover, the degradation period was prolonged from 8 months to 1 year as compared to the control. These results affirmed further that zein could be used as a new kind of natural biomaterial suitable for bone tissue engineering.

Influence of two different alcohols in the esterification of fatty acids over layered zinc stearate/palmitate

In this work, esterification of fatty acids (oleic, linoleic and stearic acid) with a commercial zinc carboxylate (a layered compound formed by simultaneous intercalation of stearate and palmitate anions) was performed. Kinetic modeling using a quasi-homogeneous approach successfully fitted experimental data at different molar ratio of fatty acids/alcohols (1-butanol and 1-hexanol) and temperature. An apparent first-order reaction related to all reactants was found and activation energy of 66 kJ/mol was reported. The catalyst showed to be unique, as it can be easily recovered like a heterogeneous catalysts behaving like ionic liquids. In addition, this catalyst demonstrated a peculiar behavior, because higher reactivity was observed with the increase in the alcohols chain length compared to the authors' previous work using ethanol.

Lipid droplets as a novel cargo of tunnelling nanotubes in endothelial cells

Intercellular communication is a fundamental process in the development and functioning of multicellular organisms. Recently, an essentially new type of intercellular communication, based on thin membrane channels between cells, has been reported. These structures, termed intercellular or tunnelling nanotubes (TNTs), permit the direct exchange of various components or signals (e.g., ions, proteins, or organelles) between non-adjacent cells at distances over 100 μm. Our studies revealed the presence of tunnelling nanotubes in microvascular endothelial cells (HMEC-1). The TNTs were studied with live cell imaging, environmental scanning electron microscopy (ESEM), and coherent anti-Stokes Raman scattering spectroscopy (CARS). Tunneling nanotubes showed marked persistence: the TNTs could connect cells over long distances (up to 150 μm) for several hours. Several cellular organelles were present in TNTs, such as lysosomes and mitochondria. Moreover, we could identify lipid droplets as a novel type of cargo in the TNTs. Under angiogenic conditions (VEGF treatment) the number of lipid droplets increased significantly. Arachidonic acid application not only increased the number of lipid droplets but also tripled the extent of TNT formation. Taken together, our results provide the first demonstration of lipid droplets as a cargo of TNTs and thereby open a new field in intercellular communication research.

The effect of N-stearoylethanolamine on plasma lipid composition in rats with experimental insulin resistance

A model of insulin resistance (IR), induced by prolonged high fat diet with high content of saturated fats was used to investigate the effect of N-stearoylethanolamine (NSE) on the composition of free fatty acids (FFA), plasma lipoprotein spectrum and content of proinflammatory cytokine TNFα in rats. The results of this work showed a rise in the content of monounsaturated fatty acids (18:1 n-9) and a reduction in the level of polyunsaturated fatty acids (20:4 n-6) in plasma of rats with experimental IR. These findings are accompanied by the increased TNFα production and significant changes in plasma lipoprotein profile of rats with the fat overload. Particularly, a decreased high-density lipoprotein (HDL) cholesterol level and increased low-density (LDL) and very low-density lipoprotein (VLDL) cholesterol level were detected. The NSE administration to obese rats with IR restored the content of mono- and polyunsaturated FFA, increased HDL cholesterol content and reduced LDL cholesterol level. In addition, the IR rats treated with NSE showed normalization in the serum TNFα level. Our results showed the restoration of plasma lipid profile under NSE administration in rats with obesity-induced IR. Considering the fact that plasma lipid composition displays the lipid metabolism in general, the NSE actions may play a significant role in the prevention of IR-associated complications.

The effect of N-stearoylethanolamine on cholesterol content, fatty acid composition and protein carbonylation level in rats with alimentary obesity-induced insulin resistance

The effect of N-stearoylethanolamine (NSE) on liver free fatty acid composition, cholesterol content and carbonylated protein level in rats with obesity-induced insulin resistance (IR) was studied in the work. The experimental insulin resistance was induced by prolonged high fat diet (58% of energy derived from fat) for 6 months combined with one injection of low-dose (15 mg/kg) of streptozotocin. The lipid assay showed a rise in liver free cholesterol content anda significant reduction in cholesterol esters level. Analyzing liver fatty acid composition, a decrease in polyunsaturated of fatty acid (PUFA) level and an increase in monounsaturated fatty acid (MUFA) content was found. Fatty acid imbalance with high content of MUFA was associated with elevated level ofprotein carbonylation. The NSE administration (50 mg/kg of body weight) for 2 weeks decreased free cholesterol content, increased cholesterol esters level and reduced free oleic fatty acid content in the liver of rats with IR. The effect of NSE on lipid imbalance led to a decrease in protein carbonylation level that may result in improvement of transmembrane protein function under obesity-induced insulin resistance state.

Dietary stearic acid leads to a reduction of visceral adipose tissue in athymic nude mice

Stearic acid (C18:0) is a long chain dietary saturated fatty acid that has been shown to reduce metastatic tumor burden. Based on preliminary observations and the growing evidence that visceral fat is related to metastasis and decreased survival, we hypothesized that dietary stearic acid may reduce visceral fat. Athymic nude mice, which are used in models of human breast cancer metastasis, were fed a stearic acid, linoleic acid (safflower oil), or oleic acid (corn oil) enriched diet or a low fat diet ad libitum. Total body weight did not differ significantly between dietary groups over the course of the experiment. However visceral fat was reduced by ∼70% in the stearic acid fed group compared to other diets. In contrast total body fat was only slightly reduced in the stearic acid diet fed mice when measured by dual-energy x-ray absorptiometry and quantitative magnetic resonance. Lean body mass was increased in the stearic acid fed group compared to all other groups by dual-energy x-ray absorptiometry. Dietary stearic acid significantly reduced serum glucose compared to all other diets and increased monocyte chemotactic protein-1 (MCP-1) compared to the low fat control. The low fat control diet had increased serum leptin compared to all other diets. To investigate possible mechanisms whereby stearic acid reduced visceral fat we used 3T3L1 fibroblasts/preadipocytes. Stearic acid had no direct effects on the process of differentiation or on the viability of mature adipocytes. However, unlike oleic acid and linoleic acid, stearic acid caused increased apoptosis (programmed cell death) and cytotoxicity in preadipocytes. The apoptosis was, at least in part, due to increased caspase-3 activity and was associated with decreased cellular inhibitor of apoptosis protein-2 (cIAP2) and increased Bax gene expression. In conclusion, dietary stearic acid leads to dramatically reduced visceral fat likely by causing the apoptosis of preadipocytes.

Stearic acid serves as a potent inhibitor of protein tyrosine phosphatase 1B

BACKGROUND/AIMS

Free fatty acids (FFAs) are implicated in diverse signal transduction pathways. The present study investigated the effects of the saturated FFA stearic acid on protein tyrosine phosphatase 1B (PTP1B) activity, Akt activity, and glucose uptake into cells relevant to insulin signal.

METHODS

PTP1B activity was assayed under the cell-free conditions. Phosphorylation of insulin receptor and Akt and glucose uptake into cells were monitored in differentiated 3T3-L1-GLUT4myc adipocytes.

RESULTS

In the cell-free PTP1B assay, stearic acid suppressed PTP1B activity in a concentration (1-30 μM)-dependent manner. For 3T3-L1- GLUT4myc adipocytes insulin phosphorylated insulin receptor at Tyr1185 and Akt at Thr308 and Ser473 in a concentration (100 fM-100 nM)-dependent manner and stimulated glucose uptake into cells in a concentration (0.1-100 nM)-dependent manner. Stearic acid (30 μM) significantly increased insulin-induced phosphorylation of insulin receptor at Tyr1185, but insulin-induced phosphorylation of Akt was not significantly enhanced. Stearic acid (30 μM) by itself promoted glucose uptake into adipocytes.

CONCLUSION

The results of the present study indicate that stearic acid serves as a potent PTP1B inhibitor, possibly causing an enhancement in the insulin receptor signaling to stimulate glucose uptake into adipocytes.

[The effect of N-stearoylethanolamine on liver phospholipid composition of rats with insulin resistance caused by alimentary obesity]

We used alimentary obesity-induced insulin resistance (IR) model in rats to investigate the influence of N-stearoylethanolamine on the content of phospholipids and their fatty acid composition. Our results show that prolonged high-fat diet triggers considerable aberrations in the composition of main phospholipids in the liver and can be one of the causes of IR in rats. In particular, the increase of phosphatidylcholine, phosphatidylethanolamine and significant decrease of other phospholipids: lysophosphatidylcholine, lysophosphatidylethanolamine, sphingomyelin, phosphatidylinositol, phosphatidylserine and diphosphaglicerol were observed. The levels of monounsaturated (erucic, nervonic, oleic) and polyunsaturated (eicosatrienoic, docosatrienoic, arachidonic) fatty acids were increased; meanwhile the content of diunsaturated acids was decreased. The NSE administration (50 mg/kg of body weight) caused restoration of the phospholipids content in the liver of rats with diet-induced IR that highly correlated with the decrease in plasma insulin level and the improvement of insulin sensitivity. Moreover, the effect of NSE was accompanied by the normalization of fatty acids composition of phospholipids that could be related to modulating influence of NSE on the activity of the main fatty acid desaturases. It is known that the imbalance in phospholipid composition of the rat liver causes substantial metabolic alterations that are associated with the development of IR. Accordingly, the compensations of the imbalance by NSE can help to restore insulin sensitivity, inhibit the development of obesity, IR and type 2 diabetes.

[N-stearoylethanolamine effect on the level of 11-hydroxycorticosteroids, cytokines IL-1, IL-6 and TNFalpha in rats with nonspecific inflammation caused by thermal burn of skin]

The mechanisms of anti-inflammatory action of saturated N-acylethanolamine--N-stearoylethanolamine (NSE) were investigated on the rat model of nonspecific inflammation (thermal burns of the skin). The results showed that the NSE application in a form of aqueous suspension (10 mg/ml) on the damaged skin area during 12 days significantly accelerated the healing process of burned wounds. NSE also prevented the increase of 11-hydroxycorticosteroids content in the blood of rats with burns. There was also found a significant decrease of cytokines (IL-1beta, IL-6 and TNFalpha) levels under the NSE action. This way may be one of the mechanisms of NSE anti-inflammatory action.

[Effects of N-stearoylethanolamine on the emotionality and learning ability of rats]

After administration of endocannabinoid-like compound N-stearoylethanolamine (NSE) at a dose of 0,1 and 5 mg/kg the anxiety level of rats in the elevated plus maze and learning ability of rats in the radial maze were investigated. It was revealed that NSE can change both innate and acquired behavior of rats. It was found that the administration of NSE decreased of anxious behavior in general, although number and duration of grooming were not affected. Administration of NSE at a dose of 5 mg/kg decreases of anxious behavior in rats but also decreases locomotor activity. Higher anxiolytic effect of the substance in the elevated plus maze and growth of learning ability in the radial maze were shown during 7 days' introduction of NSE at a dose of 0,1 mg/kg that administration of this substance at a dose of 5 mg/kg. Administration of NSE at a dose of 0.1 mg/kg significantly reduced the total number of errors in the radial maze compared to the control at the first day of conditioning with food reinforcement. The latent period of 3rd reinforcement's taking in animals in this group was lower on the 1st, 5th (P<0.05) and 6th (P <0.01) days. Nevertheless, it was found no significant differences in the behavior in rats treated with NSE in both doses throughout the study period. Therefore, NSE changes the behavior of rats and contributes to the improvement of cognitive function without negative effects specific to cannabinoid drugs.

Comparative actions of omega-3 fatty acids on in-vitro lipid droplet formation

Storage of fat into lipid droplets (LDs) is the key step in adipogenesis. Previously the omega-3 polyunsaturated fatty acid (n-3PUFA) eicosapentaenoic acid (EPA; C20:5n-3) has been shown to suppress LD formation, yet the actions of other n-3PUFA is unknown. Here, we examined the impact of the three major long chain n-3PUFA; EPA, docosapentaenoic acid (DPA; C22:5n-3) and docosahexaenoic acid (DHA; C22:6n-3) on LD formation in 3T3-L1 adipocytes. Cells were supplemented with 100µM fatty acid during differentiation. All n-3PUFA significantly reduced LD formation and the metabolic disorder marker, SCD1, in comparison to stearic acid (STA; C18:0). This action was more potent for DHA than either EPA or DPA. Furthermore, DHA significantly increased lipolysis and ATGL gene and protein expression but reduced the gene expression of three proteins related to LD formation (Perilipin A, Caveolin-1 and Cidea), compared with other n-3PUFA. Thus, DHA, above EPA and DPA, markedly suppressed fat storage in LDs in in-vitro adipocytes.

Conjugated linoleate reduces prostate cancer viability whereas the effects of oleate and stearate are cell line-dependent

BACKGROUND

In this study, responses to fatty acid treatments in commonly used prostate cancer cell culture models and variability of gene expression between them were determined.

MATERIALS AND METHODS

PC3, DU145, LNCaP, VCaP and PNT2 cells were treated with 100 μM of either oleate, stearate or conjugated linoleate. Cell proliferation and viability were assessed using trypan blue and 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay respectively. Gene expression was measured using real-time polymerase chain reaction (PCR).

RESULTS

Conjugated linoleic acid reduced cell proliferation and viability in all prostate cancer cell lines, whilst the effects of oleic and stearic acid on proliferation were found to be cell line-dependent. A reduction in gene expression of fatty acid desaturases was observed in prostate cancer cell lines compared to normal prostate cells.

CONCLUSION

Differential responses of the cell lines investigated here to fatty acid treatment suggest that multiple prostate cancer cell line models should be used when designing experiments aimed at examining lipid metabolism in prostate cancer.

[The effect of N-stearoylethanolamine on the activity of antioxidant enzymes, content of lipid peroxidation products and nitric oxide in the blood plasma and liver of rats with induced insulin-resistance]

The influence of N-stearoylethanolamine (NSE) on the content of lipid peroxidation products, activity of antioxidant enzymes and the nitric oxide level in the liver and blood plasma of rats with insulin-resistance (IR) state was investigated. IR state was induced in rats by prolonged high-fat diet (58% of energy derived from fat) for 6 months combined with one injection of streptozotocin (15 mg/kg of body weight). The existence of IR state was estimated by results of glucoso-tolerance test and blood plasma insulin content. The level of lipid peroxides products was shown to be higher in the liver of insulin resistant animals as a result of reduced superoxide dismutase and catalase activity, however, glutathione peroxidase activity was increased. The increase of nitric-oxide content in the liver and blood plasma of high-fat diet rats compared with healthy control animals was also observed. The administration of the NSE suspension per os in a dose of 50 mg/kg during 2 weeks to the rats with induced insulin-resistance state contributed to the increase of superoxide dismutase, catalase and glutathione peroxidase activity. In consequence of antioxidant enzymes activation the intensity of POL process was decreased. The NSE administration caused normalization of nitric oxide level, restoring pro-/antioxidant balance in the liver and blood plasma of rats with IR state. In conclusion, the NSE administration to the rats with insulin-resistance state restored pro-/antioxidant balance and enhanced the content of nitric oxide, therefore, improving insulin sensitivity.

[Antitoxic and antioxidant effects of N-stearoylethanolamin in the content of nanocomposite complex with doxorubicin in organs of mice with Lewis carcinoma]

The aim of the study was to evaluate the possibility to reduce the doxorubicin toxic effects by its immobilization with N-stearoylethanolamine (NSE) on nanocarier polyethylene glycol. The studied parameters of the doxorubicin toxicity were: the level of creatinine in the mice blood plasma and activity of alanine aminotransferase and aspartate aminotransferase in the blood plasma of mice. The activity of catalase superoxide dismutase, glutathione peroxidase and intensity of lipid peroxidation was determined in the tissues of the heart, kidneys and liver. Doxorubicin in the content of nanocarrier alone caused an increase of serum creatinine and aspartateaminotrasferase activity in plasma of experimental animals with carcinoma. Nanocomposite which contained doxorubicin and NSE, did not cause an increase of these parameters. It has been shown that the administration of a carrier containing doxorubicin to mice with Lewis lung carcinoma caused the decrease of catalase activity in mice with carcinoma. The combination of NSE and doxorubicin on the carrier led to the normalization of this parameter to the level of intact animals. NSE immobilized on a carrier together with doxorubicin caused a decrease in the activity of superoxide dismutase in the kidney tissue of mice with tumor. The tumor growth caused the increase of the of superoxide dismutase in mice. The administration of a carrier which contained doxorubicin and NSE normalized superoxide dismutase in heart tissue contrary of kidney. The obtained results show the antitoxic and antioxidant effects of N-stearoylethanolamine immobilized in the nanocarrier complex together with doxorubicin.

Synthesis and characterization of some novel fatty acid analogues: a preliminary investigation on their activity against human lung carcinoma cell line

BACKGROUND

Preparation of some novel heterocyclic compounds with long alkyl and alkenyl chain of cytotoxic activity.

METHODS

Gamma linolenic acid, a poly unsaturated fatty acid and stearic acid, a saturated fatty acid were isolated from the microalga Spirulina platensis. Some novel gamma linolenic acid and stearic acid analogues having 1,3,4-oxadiazole and 1,2,4-triazole were synthesized and characterized by IR, 1H NMR, 13C NMR and mass spectral analysis. Cytotoxicity of these compounds was evaluated by the growth inhibition of A-549 cells in-vitro.

RESULTS

Compound 1 and 3 showed comparable cytotoxicity against the human lung carcinoma A-549 cell lines.

Mechanism and stereoselectivity of HDAC I inhibition by (R)-9-hydroxystearic acid in colon cancer

9-Hydroxystearic acid (9-HSA) belongs to the endogenous lipid peroxidation by-products that decrease in tumors, causing as a consequence the loss of one of the control mechanisms on cell division. It acts as a histone deacetylase (HDAC, E.C 3.5.1.98) inhibitor, and the interaction of the two enantiomers of 9-HSA with the catalytic site of the enzyme, investigated by using a molecular modelling approach, has been reported to be different. In this work we tested out this prediction by synthesizing the two enantiomers (R)-9-HSA (R-9) and (S)-9-HSA (S-9) starting from the natural source methyl dimorphecolate obtained from Dimorphotheca sinuata seeds and investigating their biological activity in HT29 cells. Both enantiomers inhibit the enzymatic activity of HDAC1, HDAC2 and HDAC3, R-9 being more active; R-9 and S-9 inhibitory effect induces an increase in histone H4 acetylation. We also demonstrate that the antiproliferative effect brought about by R-9 is more pronounced as well as we observe increase of p21 transcription and protein content, while the expression of cyclin D1 is decreased. Starting from these observations it can be hypothesized that the interaction of R-9 with HDAC1 induce conformational changes in the enzyme causing loss of its interaction with other proteins, like cyclin D1 itself.

[Effect of N-stearoylethanolamine on the DNA fragmentation intensity in tumour and extratumoral tissues of the human adrenal cortex]

The effect of different concentrations of N-stearoylethanolamine (NSE 18:0) on fragmentation of DNA in the tumoural and extratumour tissues of the adrenal glands in vitro was studied. In this work the following types of tissue were investigated: extratumoural tissue from patients with hormonally active tumours, benign tumour tissue (hormonally active and hormonally inactive), tissue of malignant tumours and hyperplasic tissue of the adrenal glands (Itsenko-Cushing disease). It has been established that the NSE increases the intensity of DNA fragmentation only in the tissue of hormonally inactive tumours. Benign hormonally active tumours, malignant tumours and hyperplastic tissue of the adrenal glands were resistant to the NSE. The possible mechanisms of resistance to the drug are discussed.

Trans fatty acids: induction of a pro-inflammatory phenotype in endothelial cells

Epidemiological data have shown an association of the intake of industrial produced trans fatty acids (TFA) and sudden cardiac death. The present study examines the impact of elaidic acid (t18:1n-9) and linoelaidic acid (t18:2n-6) on the human aortic endothelial cell functional response. Trans fatty acids predominately incorporated into the phospholipid component while only a minute fraction of the total fatty acids (FA) incorporated into triacylglycerol. Trans fatty acids incorporated into the plasma membranes at the expense of the saturated-FA, stearic, palmitic, and to a lesser extent, myristic acid. Both t18:1n-9 and t18:2n-6 induced a pro-inflammatory response by elevating surface expression of intercellular adhesion molecule-1 (ICAM-1). Neither oleic nor linoleic evoked a pro-inflammatory phenotype under the maximal 50 µM treatments. Both TFA and stearic acid increased phosphorylation of the ICAM-1 transcriptional regulator, nuclear factor-κβ (NF-κβ), while oleic and linoleic acids did not appear to alter the phosphorylation status. Elaidic acid minimally affected endothelial cell growth, whereas linoelaidic acid completely inhibited growth at 100 µM and imparted limited cytotoxicity up to 300 µM. Stearic acid induced cytotoxicity at concentrations above 75 µM, while oleic and linoleic acids evoked gradual dose-dependent growth inhibition with cytotoxicity occurring only at linoleic acid concentrations greater than 200 µM. In conclusion, t18:1n-9 and t18:2n-6 fatty acids effectively incorporated into the phospholipid component of endothelial cells and subsequently induce a pro-inflammatory phenotype.

Lack of efficacy of curcumin on neurodegeneration in the mouse model of Niemann-Pick C1

In order to determine the efficacy of curcumin in ameliorating symptoms of neurodegeneration in the mouse model of Niemann-Pick C1, a variety of formulations and dosages of curcumin, one comparable to one previously reported as efficacious, were provided orally to Npc1(-/-)mice. Plasma levels of curcumin, survival, tests of motor performance, and memory (in some cases) were performed. We found variable, but mild, increases in survival (1.5% to 18%). The greatest increased survival occurred with the highest dose (which was unformulated) while the control for the lipidated formulation (containing phosphatidylcholine and stearic acid) had an equivalent impact and other formulations, while not significantly increased, are also not statistically different in effect from the highest dose. We conclude that curcumin is not a highly efficacious treatment for neurodegeneration in Npc1(-/-) mice. Phosphatidylcholine and stearic acid should be studied further.

[Antioxidative effect of the N-stearoylethanolamine in the heart tissue and blood plasma of rats under doxorubicin treatment]

The influence of N-stearoylethanolamine on the alterated antioxidant enzyme activity in the heart tissue and blood plasma of rats under the doxorubicin treatment was investigated. It was shown that doxorubicin administration caused the decrease of antioxidant enzymes activity (superoxide dismutase and glutathione peroxidase) in the heart tissue. Administration of the NSE promoted the partial normalization of these enzymes activity. It was shown that doxorubicin treatment caused the increase of the urea and creatinine level in the blood plasma of experimental animals. The NSE administration normalized the level of the urea and did not affect creatinine level.

Elevated non-esterified fatty acid concentrations during bovine oocyte maturation compromise early embryo physiology

Elevated concentrations of serum non-esterified fatty acids (NEFA), associated with maternal disorders such as obesity and type II diabetes, alter the ovarian follicular micro-environment and have been associated with subfertility arising from reduced oocyte developmental competence. We have asked whether elevated NEFA concentrations during oocyte maturation affect the development and physiology of zygotes formed from such oocytes, using the cow as a model. The zygotes were grown to blastocysts, which were evaluated for their quality in terms of cell number, apoptosis, expression of key genes, amino acid turnover and oxidative metabolism. Oocyte maturation under elevated NEFA concentrations resulted in blastocysts with significantly lower cell number, increased apoptotic cell ratio and altered mRNA abundance of DNMT3A, IGF2R and SLC2A1. In addition, the blastocysts displayed reduced oxygen, pyruvate and glucose consumption, up-regulated lactate consumption and higher amino acid metabolism. These data indicate that exposure of maturing oocytes to elevated NEFA concentrations has a negative impact on fertility not only through a reduction in oocyte developmental capacity but through compromised early embryo quality, viability and metabolism.

[Effect of N-stearoylethanolamine on free amino acid levels in rat plasma and liver with burn]

The effect of the endocannabinoid congener N-stearoylethanolamine (NSE) on the content of plasma and liver free amino acids in burned rats was studied. The animals after the thermal burn of the skin received per os during 7 days the water suspension of NSE in the doze 10 mg/kg of body weight. In the other group of rats the suspension was applied on the wound (the concentration of NSE was 10 mg/ml). In experimental animals the total amount of free amino acids in plasma decreased after burn while the total amount of free amino acids in liver significantly increased. In burn animals the ratio of plasma and liver Phe/Tyr and Gly/Val was found to be augmented while the Fischer ratio (Ile+Leu+Val/Phe+Tyr) diminished compared with intact rats. It was shown for the first time that NSE caused normalization of the concentration of some free amino acids and of Phe/Tyr, Gly/Val ratios, and the Fischer ratio in blood plasma and liver of rats with the burn injury. Altogether, these data demonstrate that NSE possesses adaptogenic properties, and is involved in the organism response to a burn. These findings suggest possibility of NSE usage for burn treatment.

Molecular mechanisms by which saturated fatty acids modulate TNF-α expression in mouse macrophage lineage

Many macrophage functions are modulated by fatty acids (FAs), including cytokine release, such as tumor necrosis factor-α (TNF-α). TNF-α is of great interest due to its role in the inflammation process observed in several diseases such as rheumatoid arthritis, atherosclerosis, and obesity. However, the mechanisms by which FA effects occur have not been completely elucidated yet. In this study, we used a mouse monocyte lineage (J774 cells) to evaluate the effect of 50 and 100 μM of saturated (palmitic and stearic acids), monounsaturated (oleic acid) and polyunsaturated (linoleic acid) FAs on TNF-α production. Alterations in gene expression, poly(A) tail length and activation of transcription factors were evaluated. Oleic and linoleic acids, usually known as neutral or pro-inflammatory FA, inhibited LPS-induced TNF-α secretion by the cells. Saturated FAs were potent inducers of TNF-α expression and secretion under basal and inflammatory conditions (in the presence of LPS). Although the effect of the saturated FA was similar, the mechanism involved in each case seem to be distinct, as palmitic acid increased EGR-1 and CREB binding activity and stearic acid increased mRNA poly(A) tail. These results may contribute to the understanding of the molecular mechanisms by which saturated FAs modulate the inflammatory response and may lead to design of associations of dietary and pharmacological strategies to counteract the pathological effects of TNF-α.

Clytostoma callistegioides (Bignoniaceae) wax extract with activity on aphid settling

A bioassay-guided fractionation of leaf extracts from Clytostoma callistegioides (Cham.) Bureau ex Griseb. (Bignoniaceae) led to isolation of a natural mixture of four fatty acids with anti-insect activity against aphids. The compounds were identified by GC-MS as palmitic, stearic, linoleic and linolenic acids and quantified as their methyl esters. The anti-aphid activity of the natural mixture was traced to linolenic and linoleic acids, as shown by the settling inhibition activity of synthetic samples. Interestingly, the saturated acids (palmitic and stearic) tested alone stimulated settling on one of the tested aphids (Myzus persicae), but not on the other tested species (Rhopalosiphum padi). Although ubiquitous, none of these free acids have been previously reported in this Bignoniaceae species. The leaf surface chemistry, which is likely involved in modulating aphid settling behavior, was further investigated for the occurrence of lipophilic substances by histochemical staining. Short, stalked glandular trichomes, previously undescribed for this species, stained with osmium tetroxide and Sudan III, suggesting that the secretion of the defensive acids is related to these surface trichomes.

[Effects of 9,10-dihydroxysteatic acid on glucose metabolism in KKAy mice]

OBJECTIVE

To study the effect of 9,10-dihydroxystearic acid (DHSA) on glucose tolerance and insulin sensitivity in KKAy diabetic mice.

METHODS

48 male KKAy mice were randomly divided into four groups and were fed with high fat diet containing 4% DHSA, 2% DHSA, 4% Olive oil and 4% Corn oil, respectively. Glucose tolerance and insulin sensitivity were measured after 5 and 6 weeks respectively. Effects of DHSA on activating PPAR-alpha and PPAR-gamma in CV-1 cells were also carried out.

RESULTS

In glucose tolerance test, the blood glucose at 0.5 h and 1 h and the area under glucose curve in the group fed with 4% DHSA diet were significantly lower than those of other groups. In insulin sensitivity test, the blood glucose level at 0.5 h and 1 h after injection of insulin was lower in the 4% DHSA diet group, indicating the insulin sensitivity of this group was obviously higher than other groups (P < 0.05). The body weight of the mice fed with 4% DHSA diet was much lower than those mice fed with 4% Corn diet (P < 0.05). 5 - 20 micromol/L DHSA did not activate PPAR-gamma in CV-1 cells but 50 - 100 micromol/L DHSA activated PPARgamma in a dose-dependent way although the activating effect of DHSA on PPARgamma was significantly lower than that of rosiglitazone. DHSA did not activate PPAR-alpha in CV-1 cells.

CONCLUSION

DHSA may improve glucose tolerance and insulin sensitivity in KKAy mice and the effect might be related to the activation of PPAR-gamma by DHSA.

Polyunsaturated docosahexaenoic acid suppresses oxidative stress induced endothelial cell calcium influx by altering lipid composition in membrane caveolar rafts

OBJECTIVE

To determine whether DHA suppresses oxidative stress induced endothelial cell calcium influx by altering lipid composition and TRPC1 distribution in membrane rafts.

METHODS

Endothelial cells (EC) were pretreated with DHA or stearic acid, then incubated for another 3h with media containing H(2)O(2). Membrane lipid rafts were isolated using the discontinuous sucrose density gradient ultracentrifugation method. Intracellular calcium was detected with laser scanning confocal microscope. TRPC1 protein in membrane fractions was detected by immunoblotting. Membrane fatty acids compositions were analyzed by gas chromatography; raft cholesterol level was assayed by an Amplex Red Cholesterol Assay kit, and DAG concentration was quantified by a DAG kinase assay.

RESULTS

DHA significantly reduced oxidative stress induced calcium influx; pretreated with DHA the n-3 PUFAs were significantly increased in raft fractions, as well as saturated myristic acid, palmitic acid content of membrane rafts in EC; while the stearic acid, monounsaturated oleic acid and cis-oleic acid were decreased. Incubation with DHA also significantly reduced the amount of SM and cholesterol levels in the raft. Interestingly, we fractioned plasma membrane subcellular compartments and discovered that certain amounts of TRPC1 existed in detergent-resistant plasma membrane fractions of EC. After DHA treatment, TRPC1 was partly displaced from lipid raft to detergent-soluble membrane fractions.

CONCLUSIONS

DHA significantly reduces oxidative stress induced endothelial calcium influx, this effect might be associated with, at least in part, altered raft lipid environment, and suppresses TRPC1-mediated calcium signaling pathway by partially displacing TRPC1 from membrane caveolar lipid rafts.