Membrane lipid remodeling modulates γ-secretase processivity.

Imbalances in the amounts of amyloid-ß peptides (Aß) generated by the membrane proteases ß- and γ-secretase are considered as a trigger of Alzheimer's disease (AD). Cell-free studies of γ-secretase have shown that increasing membrane thickness modulates Aß generation but it has remained unclear if these effects are translatable to cells. Here we show that the very long-chain fatty acid erucic acid (EA) triggers acyl chain remodeling in AD cell models, resulting in substantial lipidome alterations which included increased esterification of EA in membrane lipids. Membrane remodeling enhanced γ-secretase processivity, resulting in the increased production of the potentially beneficial Aß37 and/or Aß38 species in multiple cell lines. Unexpectedly, we found that the membrane remodeling stimulated total Aß secretion by cells expressing WT γ-secretase but lowered it for cells expressing an aggressive familial AD mutant γ-secretase. We conclude that EA-mediated modulation of membrane composition is accompanied by complex lipid homeostatic changes that can impact amyloidogenic processing in different ways and elicit distinct γ-secretase responses, providing critical implications for lipid-based AD treatment strategies.

The functional divergence of homologous GPAT9 genes contributes to the erucic acid content of Brassica napus seeds.

BACKGROUND: The early allopolyploid Brassica napus was a hybrid of two Brassica species, that had undergone a whole genome duplication event followed by genome restructuring, including deletions and small scale duplications. A large number of homologous genes appeared functional divergence during species domestication. Due to the high conservation of de novo glycerolipid biosynthesis, multiple homologues of glycerol-3-phosphate acyltransferases (GPATs) have been found in B. napus. Moreover, the functional variances among these homologous GPAT-encoding genes are unclear. RESULTS: In this study, four B. napus homologous genes encoding glycerol-3-phosphate acyltransferase 9 (BnaGPAT9) were characterized. Although a bioinformatics analysis indicated high protein sequence similarity, the homologues demonstrated tissue-specific expression patterns and functional divergence. Yeast genetic complementation assays revealed that BnaGPAT9-A1/C1 homologues but not BnaGPAT9-A10/C9 homologues encoded functional GPAT enzymes. Furthermore, a single nucleotide polymorphism of BnaGPAT9-C1 that occurred during the domestication process was associated with enzyme activity and contributed to the fatty acid composition. The seed-specific expression of BnGPAT9-C11124A increased the erucic acid content in the transformant seeds. CONCLUSIONS: This study revealed that BnaGPAT9 gene homologues evolved into functionally divergent forms with important roles in erucic acid biosynthesis.

Erucic acid increases the potency of cisplatin-induced colorectal cancer cell death and oxidative stress by upregulating the TRPM2 channel.

Erucic acid (ErA) is a source of omega-9 monounsaturated fatty acids. ErA exhibited antitumor effects by causing apoptosis and oxidative stress in tumor cells, with the exception of the HT-29 human colorectal cancer cell line. The apoptotic and Ca2+ signaling pathways in tumor cells are triggered when mitochondrial Ca2+ and Zn2+ accumulation produce reactive free oxygen species (ROS), which in turn activate TRPM2. ErA-induced ROS and TRPM2 stimulation may augment the anticancer action of cisplatin (CSP). We aimed to study the effects of ErA and CSP incubations on ROS, apoptosis, and cell death in the HT-29 cells by activating TRPM2. The cells were divided into five groups: control, ErA (200 µM for 48 h), CSP (25 µM for 24 h), and ErA + CSP + TRPM2 antagonists (200 µM carvacrol and 25 µM N-(p-amylcinnamoyl)anthranilic acid for 24 h). The TRPM2 antagonists reduced ErA plus CSP-induced increases in H2O2-induced intracellular free Ca2+ concentration ([Ca2+]c) and adenosine diphosphate-ribose-caused TRPM2 currents. ErA and CSP were found to cause apoptosis and cell death by raising the intracellular free Zn2+ concentration (Zn2+]c), caspase-3, -8, and -9, mitochondrial membrane dysfunction, and ROS, while lowering reduced glutathione, cell viability, and cell number. The oxidative, apoptotic, and tumor cell death effects of CSP in the cells were enhanced by the increase of ErA-mediated [Ca2+]c and Zn2+]c entering mitochondria through the activation of TRPM2. In conclusion, we observed that the combination of ErA and CSP was synergistic via TRPM2 activation for the treatment of HT-29 tumor cells.

Morpho-Physiochemical Indices and Transcriptome Analysis Reveal the Role of Glucosinolate and Erucic Acid in Response to Drought Stress during Seed Germination of Rapeseed.

The global expansion of rapeseed seed quality has been focused on maintaining glucosinolate (GSL) and erucic acid (EA) contents. However, the influence of seed GSL and EA contents on the germination process under drought stress remains poorly understood. Herein, 114 rapeseed accessions were divided into four groups based on GSL and EA contents to investigate their performance during seed imbibition under drought stress. Our results revealed significant variations in seed germination-related traits, particularly with higher GSL and EA, which exhibited higher germination % (G%) and lower mean germination time (MGT) under drought stress conditions. Moreover, osmoregulation, enzymatic system and hormonal regulation were improved in high GSL and high EA (HGHE) versus low GSL and low EA (LGLE) seeds, indicating the essential protective role of GSL and EA during the germination process in response to drought stress. The transcriptional regulation mechanism for coordinating GSL-EA-related pathways in response to drought stress during seed imbibition was found to involve the differential expression of sugar metabolism-, antioxidant-, and hormone-related genes with higher enrichment in HGHE compared to LGLE seeds. GO enrichment analysis showed higher variations in transcription regulator activity and DNA-binding transcription factors, as well as ATP and microtubule motor activity in GSL-EA-related pathways. Furthermore, KEGG analysis identified cellular processes, environmental information processing, and metabolism categories, with varied gene participation between GSL, EA and GSL-EA-related pathways. For further clarification, QY7 (LGLE) seeds were primed with different concentrations of GSL and EA under drought stress conditions. The results showed that 200 µmol/L of GSL and 400 µmol/L of EA significantly improved G%, MGT, and seedling fresh weight, besides regulating stress and fatty acid responsive genes during the seed germination process under drought stress conditions. Conclusively, exogenous application of GSL and EA is considered a promising method for enhancing the drought tolerance of LGLE seeds. Furthermore, the current investigation could provide a theoretical basis of GSL and EA roles and their underlying mechanisms in stress tolerance during the germination process.

Enhancing Erucic Acid and Wax Ester Production in Brassica carinata through Metabolic Engineering for Industrial Applications.

Metabolic engineering enables oilseed crops to be more competitive by having more attractive properties for oleochemical industrial applications. The aim of this study was to increase the erucic acid level and to produce wax ester (WE) in seed oil by genetic transformation to enhance the industrial applications of B. carinata. Six transgenic lines for high erucic acid and fifteen transgenic lines for wax esters were obtained. The integration of the target genes for high erucic acid (BnFAE1 and LdPLAAT) and for WEs (ScWS and ScFAR) in the genome of B. carinata cv. 'Derash' was confirmed by PCR analysis. The qRT-PCR results showed overexpression of BnFAE1 and LdPLAAT and downregulation of RNAi-BcFAD2 in the seeds of the transgenic lines. The fatty acid profile and WE content and profile in the seed oil of the transgenic lines and wild type grown in biotron were analyzed using gas chromatography and nanoelectrospray coupled with tandem mass spectrometry. A significant increase in erucic acid was observed in some transgenic lines ranging from 19% to 29% in relation to the wild type, with a level of erucic acid reaching up to 52.7%. Likewise, the transgenic lines harboring ScFAR and ScWS genes produced up to 25% WE content, and the most abundant WE species were 22:1/20:1 and 22:1/22:1. This study demonstrated that metabolic engineering is an effective biotechnological approach for developing B. carinata into an industrial crop.

Cultivated Winter-Type Lunaria annua L. Seed: Deciphering the Glucosinolate Profile Integrating HPLC, LC-MS and GC-MS Analyses, and Determination of Fatty Acid Composition.

Lunaria annua L. (Brassicaceae) is an ornamental plant newly identified in Europe as a promising industrial oilseed crop for its valuable very-long-chain monounsaturated fatty acids (MUFAs), especially erucic acid (EA) and nervonic acid (NA). L. annua seeds were obtained from annual winter-type plants selected and cultivated in Northern France. Using a systematic multiple-method approach, we set out to determine the profile and content of glucosinolates (GSLs), which are the relevant chemical tag of Brassicaceae. Intact GSLs were analyzed through a well-established LC-MS method. Identification and quantification were performed by HPLC-PDA of desulfo-GSLs (dGLs) according to the official EU ISO method. Moreover, GSL structures were confirmed by GC-MS analysis of the related isothiocyanates (ITCs). Seven GSLs were identified, directly or indirectly, as follows: 1-methylethyl GSL, (1S)-1-methylpropyl GSL, (Rs)-5-(methylsulfinyl)pentyl GSL, (Rs)-6-(methylsulfinyl)hexyl GSL, (2S)-2-hydroxy-4-pentenyl GSL, 2-phenylethyl GSL, and 1-methoxyindol-3-ylmethyl GSL. In other respects, the FA composition of the seed oil was determined. Results revealed cultivated L. annua seed to be a source of NA-rich oil, and presscake as a valuable coproduct. This presscake is indeed rich in GSLs (4.3% w/w), precursors of promising bioactive molecules for agricultural and nutraceutical applications.

Impact of dietary vitamin (E) and Eruca sativa seeds powder on broiler productivity, health, carcass characteristics, and meat quality.

This investigation examined the impact of nutritional vitamin E (VE) and Eruca sativa seeds powder (ESSP) on broilers' performance, physiological, and meat quality. A total of 350 two-day-old Arbor Acres broiler chicks were used in this study. Chicks were allocated into five dietary treatments as follows: control (fed a basic diet), VE treatment (fed a basic diet supplemented with 150 mg/kg diet), the third, fourth, and fifth treatments were fed a basic diet supplied by different levels of ESSP (0.1, 0.2 and 0.4 g/kg diet). Outcomes showed that chicks of VE treatment or ESSP (0.2 g/kg) significantly improved vital body weight (BW), body weight gain (BWG) and feed conversion ratio (FCR). Additionally, relevant dressing and hind parts of the carcass for birds of VE treatment or ESSP at different levels were significantly increased. The results showed a significant improvement in meat quality traits. Moreover, ESSP (0.1 and 0.2 g/kg) groups represented a significant decrease in the total bacterial count and E. coli compared with other groups. In conclusion, ESSP positively affected broiler performance, hematological, and immunological indices, carcass characteristics, intestinal bacterial count, meat quality, and cooking properties of the resulting meat, especially at the level of (0.2 g/kg).

Changes in fatty acids in Brassica juncea L. oil grown under two simulated conditions of fluoride contamination.

Rapeseed, the second-most-important vegetable oil source, is cultivated in various areas of India where both groundwater and soil are contaminated with fluoride (F-). Furthermore, the frequent use of F- contaminated groundwater for irrigation leads to accumulation of F- in surface and sub-surface soil. The study aims to compare the morphological and biochemical changes in Brassica juncea L., the variations in its fatty acids (FAs) composition and oil yield, under two regimes of F- contaminated soils: (i) pre-contaminated soil (Tr) and (ii) irrigation with F- contaminated water (Ir). The level of F- (µg g-1) in the plant tissues (root, leaf, and grain) was significantly higher in Ir_10 (18.3, 14.7, and 2.8, respectively) than in Tr_10 (4.3, 2.6, and 0.77, respectively), while the oil yield was significantly lower with Ir_10 (19.5%) than with Tr_10 (44.9%). The phytoremediation potential of F- by Brassica juncea L. is greater in Tr regime than in the Ir regime. The erucic acid content (%), which is detrimental to cardiac health, increased to 67.37% (Ir_10) and 58.3% (Tr_10) from 57.73% (control). Thus, the present study shows that irrigation with F- contaminated water results in greater toxicity and accumulation in plants and is not safe for human health.

Irrigation with F^­ contaminated water results in a greater accumulation of F^­ in mustard than cultivated on pre-contaminated soil. The level of erucic acid in mustard oil enhances against F^­ exposure.

Erucic Acid-Both Sides of the Story: A Concise Review on Its Beneficial and Toxic Properties.

Erucic acid (EA) is monounsaturated fatty acid (22:1 n-9), synthesized in the seeds of many plants from the Brassicaceae family, with Brassica napus, B. rapa, or B. carinata considered as its richest source. As the compound has been blamed for the poisoning effect in Toxic Oil Syndrome, and some data indicated its cardiotoxicity to rats, EA has been for decades classified as toxic substance, the use of which should be avoided. However, the cardiac adverse effects of EA have not been confirmed in humans, and the experiments in animal models had many limitations. Thus, the aim of this review was to present the results of the so far published studies on both toxic, and pharmacological properties of EA, trying to answer the question on its future medicinal use. Despite the ambiguous and relatively small data on toxic and beneficial effects of EA it seems that the compound is worth investigating. Further research should be particularly directed at the verification EA toxicity, more in-depth studies on its neuroprotective and cytotoxic properties, but also its use in combination with other drugs, as well as its role as a drug carrier.

Broccoli, Kale, and Radish Sprouts: Key Phytochemical Constituents and DPPH Free Radical Scavenging Activity.

Our research group previously found that broccoli sprouts possess neuroprotective effects during pregnancy. The active compound has been identified as sulforaphane (SFA), obtained from glucosinolate and glucoraphanin, which are also present in other crucifers, including kale. Sulforaphene (SFE), obtained from glucoraphenin in radish, also has numerous biological benefits, some of which supersede those of sulforaphane. It is likely that other components, such as phenolics, contribute to the biological activity of cruciferous vegetables. Notwithstanding their beneficial phytochemicals, crucifers are known to contain erucic acid, an antinutritional fatty acid. The aim of this research was to phytochemically examine broccoli, kale, and radish sprouts to determine good sources of SFA and SFE to inform future studies of the neuroprotective activity of cruciferous sprouts on the fetal brain, as well as product development. Three broccoli: Johnny's Sprouting Broccoli (JSB), Gypsy F1 (GYP), and Mumm's Sprouting Broccoli (MUM), one kale: Johnny's Toscano Kale (JTK), and three radish cultivars: Black Spanish Round (BSR), Miyashige (MIY), and Nero Tunda (NT), were analyzed. We first quantified the glucosinolate, isothiocyanate, phenolics, and DPPH free radical scavenging activity (AOC) of one-day-old dark- and light-grown sprouts by HPLC. Radish cultivars generally had the highest glucosinolate and isothiocyanate contents, and kale had higher glucoraphanin and significantly higher sulforaphane content than the broccoli cultivars. Lighting conditions did not significantly affect the phytochemistry of the one-day-old sprouts. Based on phytochemistry and economic factors, JSB, JTK, and BSR were chosen for further sprouting for three, five, and seven days and subsequently analyzed. The three-day-old JTK and radish cultivars were identified to be the best sources of SFA and SFE, respectively, both yielding the highest levels of the respective compound while retaining high levels of phenolics and AOC and markedly lower erucic acid levels compared to one-day-old sprouts.

Enhancing very long chain fatty acids production in Yarrowia lipolytica.

BACKGROUND: Very long chain fatty acids (VLCFA) and their derivatives are industrially attractive compounds. The most important are behenic acid (C22:0) and erucic acid (C22:1Δ13), which are used as lubricants, and moisturizers. C22:0 and C22:1Δ13 have also potential for biofuel production. These fatty acids are conventionally obtained from plant oils. Yarrowia lipolytica is an oleaginous yeast with a long history of gene manipulations resulting in the production of industrially interesting compounds, such as organic acids, proteins, and various lipophilic molecules. It has been shown previously that it has potential for the production of VLCFA enriched single cell oils. RESULTS: The metabolism of Y. lipolytica was redesigned to achieve increased production of VLCFA. The effect of native diacylglycerol acyltransferases of this yeast YlLro1p, YlDga1p, and YlDga2p on the accumulation of VLCFA was examined. It was found that YlDga1p is the only enzyme with a beneficial effect. Further improvement of accumulation was achieved by overexpression of 3-ketoacyl-CoA synthase (TaFAE1) under 8UAS-pTEF promoter and blockage fatty acid degradation pathway by deletion of YlMFE1. The best-producing strain YL53 (Δmfe, pTEF-YlDGA1, 8UAS-pTEF-TaFAE1) produced 120 µg of very long chain fatty acids per g of produced biomass, which accounted for 34% of total fatty acids in biomass. CONCLUSIONS: Recombinant strains of Y. lipolytica have proved to be good producers of VLCFA. Redesign of lipid metabolism pathways had a positive effect on the accumulation of C22:1Δ13 and C22:0, which are technologically attractive compounds.

A review on neuropharmacological role of erucic acid: an omega-9 fatty acid from edible oils.

Neurodegenerative diseases (ND) are characterised by loss of neurons in the brain and spinal cord. For the normal functioning of the brain, divers group of fatty acids in the form of glycerophospholipids, glycerol ether lipids, cerebrosides, sulfatides, and gangliosides are essential. They are present abundantly in the nervous system and are actively involved in both the development and maintenance of the nervous system. A dietary deficiency of essential fatty acid during development results in hypomyelination state which affects various neuronal functions. Several studies suggested that age remains the primary risk factor for almost all neurodegenerative disorders. The potential contribution of these fatty acids in the progression of neurodegenerative disorders is indispensable. Erucic acid an omega 9 fatty acid, which is obtained from edible oils has proven to cause myocardial lipidosis, heart lesions and hepatic steatosis in animals therefore, its content in edible oils is restricted to certain levels by regulatory agencies. However, erucic acid in the form of a mixture with oleic acid is often used as a dietary treatment for the management of adrenoleukodystrophy without any cardiotoxicity. Our literature search revealed that, erucic acid reported to enhance cognitive function, interact with peroxisome proliferator activated receptors (PPARs), inhibit elastase and thrombin. In this review first we have attempted to describe the relationship between fatty acids and neurodegeneration followed by a description on the pharmacology of erucic acid. The overall purpose of this review is to analyse toxic and beneficial neuropharmacological effects of erucic acid.

Could dietary erucic acid lower risk of brain tumors? An epidemiological look to Chinese population with implications for prevention and treatment.

Erucic acid, an omega-9 monounsaturated fatty acid present in Brassicaceae plants (rapeseed and mustard oils) is highly consumed by the Chinese population and according to several global survey studies, its highest levels are encountered in the Chinese women's milk. Erucic acid is an activating ligand of the transcription factor PPARδ and an inhibitor of the transcriptional activity of PPARγ, which drive tumorigenesis of glioblastomas and medulloblastomas. In this theoretical review, we propose that erucic acid in diet may associate with the risk of brain tumors. High grade brain tumors including medulloblastomas in children and glioblastomas in adults have devastating consequences for human health and the latter tumors are practically incurable. CONCORD-3 epidemiological study recently published in 2021 revealed a low ratio of medulloblastomas in the pediatric age group and also a low ratio of glioblastomas in adults in the Chinese population. It is certain that such profound differences can not be attributed to a single genetic factor or a single nurture pattern. It is very likely that multiple hereditary, nutritional and environmental factors are responsible for these lower ratios; yet here we propose that erucic acid may be one of the contributing factors. If future epidemiological studies and animal models show antitumor activity of erucic acid regarding brain neoplasias, it can be utilized as a preventive strategy for populations possessing very high risks to develop brain tumors such as those harbouring hereditary syndromes increasing the vulnerability to develop such malignancies.

Design and evaluation of erucic acid-phytosphingosine structured cationic nanoemulsions as a plasmid DNA delivery system against breast cancer cells.

This study is focused on the preparation and characterization of erucic acid (EA) and phytosphingosine (PS) containing cationic nanoemulsions (NEs) for plasmid DNA (pDNA) delivery. Repurposing of cationic agents guided us to PS, previously used for enhanced interaction with negatively charged surfaces. It was reported that EA might act anti-tumoral on C6 glioma, melanoma, neuroblastoma, and glioblastoma. However, there is only one study about mixed oleic acid-EA liposomes. This gap attracted our interest in the possible synergistic effects of PS and EA on MDA-MB-231 and MCF-7 breast cancer cells. Three cationic NEs (NE 1, NE 2, and NE 3) were prepared and characterized in terms of droplet size (DS), polydispersity index (PDI), and zeta potential (ZP) before and after complexation with pDNA, long-term stability, SDS release, cytotoxicity, and transfection studies. The cationic NEs had DSs of <200 nm, PDIs <0.3, and ZPs > +30 mV. Long-term stability studies revealed that NE 2 and NE 3 were stable. NE 1-pDNA had appropriate particle properties. NE 2 reduced the viability of MDA-MB-231 cells to 11% and of MCF-7 cells to 13% and resulted in the highest number of transfected cells. To sum up, NE 2 containing PS and EA is appropriate for delivering pDNA.

Peroxisomal oxidation of erucic acid suppresses mitochondrial fatty acid oxidation by stimulating malonyl-CoA formation in the rat liver.

Feeding of rapeseed (canola) oil with a high erucic acid concentration is known to cause hepatic steatosis in animals. Mitochondrial fatty acid oxidation plays a central role in liver lipid homeostasis, so it is possible that hepatic metabolism of erucic acid might decrease mitochondrial fatty acid oxidation. However, the precise mechanistic relationship between erucic acid levels and mitochondrial fatty acid oxidation is unclear. Using male Sprague-Dawley rats, along with biochemical and molecular biology approaches, we report here that peroxisomal ß-oxidation of erucic acid stimulates malonyl-CoA formation in the liver and thereby suppresses mitochondrial fatty acid oxidation. Excessive hepatic uptake and peroxisomal ß-oxidation of erucic acid resulted in appreciable peroxisomal release of free acetate, which was then used in the synthesis of cytosolic acetyl-CoA. Peroxisomal metabolism of erucic acid also remarkably increased the cytosolic NADH/NAD+ ratio, suppressed sirtuin 1 (SIRT1) activity, and thereby activated acetyl-CoA carboxylase, which stimulated malonyl-CoA biosynthesis from acetyl-CoA. Chronic feeding of a diet including high-erucic-acid rapeseed oil diminished mitochondrial fatty acid oxidation and caused hepatic steatosis and insulin resistance in the rats. Of note, administration of a specific peroxisomal ß-oxidation inhibitor attenuated these effects. Our findings establish a cross-talk between peroxisomal and mitochondrial fatty acid oxidation. They suggest that peroxisomal oxidation of long-chain fatty acids suppresses mitochondrial fatty acid oxidation by stimulating malonyl-CoA formation, which might play a role in fatty acid-induced hepatic steatosis and related metabolic disorders.

Development of novel clubroot resistant rapeseed lines (Brassica napus L.) effective against Japanese field isolates by marker assisted selection.

Clubroot is an important disease infectible to cruciferous plants and a major threat to rapeseed production in Japan. However, no clubroot resistant rapeseed cultivars have been released. We surveyed pathotype variation of six isolates collected from rapeseed fields and found they were classified as pathotype groups 2 and 4 using Japanese F1 Chinese cabbage cultivars. We produced the resynthesized clubroot resistant Brassica napus harboring two resistant loci, Crr1 and Crr2, by interspecific crossing and developed resistant rapeseed lines for southern and northern regions by marker-assisted selection and backcrossing. We improved the DNA marker for erucic acid content to remove linkage drag between Crr1 and high erucic acid content and successfully selected lines with clubroot resistance and zero erucic acid for northern regions. A novel line, 'Tohoku No. 106', suitable for southern regions showed stable resistance against all six isolates and high performance in infested fields. We conclude that Crr1 and Crr2 are important genes for CR rapeseed breeding and marker-assisted selection is effective in improving clubroot resistance.

Erucic Acid-Rich Yellow Mustard Oil Improves Insulin Resistance in KK-Ay Mice.

Obesity is a major risk factor for some metabolic disorders including type 2 diabetes. Enhancement of peroxisome proliferator-activated receptor (PPAR) γ, a master regulator of adipocyte differentiation, is known to increase insulin-sensitive small adipocytes. In contrast, decreased PPARγ activity is also reported to improve insulin resistance. We have previously identified erucic acid as a novel natural component suppressing PPARγ transcriptional activity. In this study, we investigated the effect of erucic acid-rich yellow mustard oil (YMO) on obese/diabetic KK-Ay mice. An in vitro luciferase reporter assay and mesenchymal stem cell (MSC) differentiation assay revealed that 25 µg/mL YMO significantly inhibited PPARγ transcriptional activity and differentiation of MSCs into adipocytes but promoted their differentiation into osteoblasts. In KK-Ay mice, dietary intake of 7.0% (w/w) YMO significantly decreased the surrogate indexes for insulin resistance and the infiltration of macrophages into adipose tissue. Furthermore, 7.0% YMO increased bone mineral density. These results suggest that YMO can ameliorate obesity-induced metabolic disorders.

Functional analysis of ß-ketoacyl-CoA synthase from biofuel feedstock Thlaspi arvense reveals differences in the triacylglycerol biosynthetic pathway among Brassicaceae.

KEY MESSAGE: Differences in FAE1 enzyme affinity for the acyl-CoA substrates, as well as the balance between the different pathways involved in their incorporation to triacylglycerol might be determinant of the different composition of the seed oil in Brassicaceae. Brassicaceae present a great heterogeneity of seed oil and fatty acid composition, accumulating Very Long Chain Fatty Acids with industrial applications. However, the molecular determinants of these differences remain elusive. We have studied the ß-ketoacyl-CoA synthase from the high erucic feedstock Thlaspi arvense (Pennycress). Functional characterization of the Pennycress FAE1 enzyme was performed in two Arabidopsis backgrounds; Col-0, with less than 2.5% of erucic acid in its seed oil and the fae1-1 mutant, deficient in FAE1 activity, that did not accumulate erucic acid. Seed-specific expression of the Pennycress FAE1 gene in Col-0 resulted in a 3 to fourfold increase of erucic acid content in the seed oil. This increase was concomitant with a decrease of eicosenoic acid levels without changes in oleic ones. Interestingly, only small changes in eicosenoic and erucic acid levels occurred when the Pennycress FAE1 gene was expressed in the fae1-1 mutant, with high levels of oleic acid available for elongation, suggesting that the Pennycress FAE1 enzyme showed higher affinity for eicosenoic acid substrates, than for oleic ones in Arabidopsis. Erucic acid was incorporated to triacylglycerol in the transgenic lines without significant changes in their levels in the diacylglycerol fraction, suggesting that erucic acid was preferentially incorporated to triacylglycerol via DGAT1. Expression analysis of FAE1, AtDGAT1, AtLPCAT1 and AtPDAT1 genes in the transgenic lines further supported this conclusion. Differences in FAE1 affinity for the oleic and eicosenoic substrates among Brassicaceae, as well as their incorporation to triacylglycerol might explain the differences in composition of their seed oil.

The impact of reducing fatty acid desaturation on the composition and thermal stability of rapeseed oil.

Oilseed rape (Brassica napus) is the third largest source of vegetable oil globally. In addition to food uses, there are industrial applications that exploit the ability of the species to accumulate the very-long-chain fatty acid (VLCFA) erucic acid in its seed oil, controlled by orthologues of FATTY ACID ELONGASE 1 (Bna.FAE1.A8 and Bna.FAE1.C3). The proportion of polyunsaturated fatty acids (PUFAs) in rapeseed oil is predicted to affect its thermal stability and is controlled by orthologues of FATTY ACID DESATURASE 2, particularly Bna.FAD2.C5. Our aim was to develop rapeseed lines combining high erucic and low PUFA characters and to assess the impact on thermal stability of the oil they produce. The new type of rapeseed oil (high erucic low polyunsaturate; HELP) contained a substantially greater proportion of erucic acid (54%) compared with high erucic rapeseed oil (46%). Although the total VLCFA content was greater in oil from HELP lines (64%) than from high erucic rapeseed (57%), analysis of triacylglycerol composition showed negligible incorporation of VLCFAs into the sn-2 position. Rancimat analysis showed that the thermal stability of rapeseed oil was improved greatly as a consequence of reduction of PUFA content, from 3.8 and 4.2 h in conventional low erucic and high erucic rapeseed oils, respectively, to 11.3 and 16.4 h in high oleic low PUFA (HOLP) and HELP oils, respectively. Our results demonstrate that engineering of the lipid biosynthetic pathway of rapeseed, using traditional approaches, enables the production of renewable industrial oils with novel composition and properties.

Erucic acid, a nutritional PPARδ-ligand may influence Huntington's disease pathogenesis.

Increasing recent evidence suggests a key role of oligodendroglial injury and demyelination in the pathophysiology of Huntington's Disease (HD) and the transcription factor PPARδ is critical for oligodendroglial regeneration and myelination. PPARδ directly involves in the pathogenesis of HD and treatment with a brain-permeable PPARδ-agonist (KD3010) alleviates its severity in mice. Erucic acid (EA) is also a PPARδ-ligand ω9 fatty acid which is highly consumed in Asian countries through ingesting cruciferous vegetables such as rapeseed (Brassica napus) and indian mustard (Brassica juncea). EA is also an ingredient of Lorenzo's oil employed in the medical treatment of adrenoleukodystrophy and can be converted to nervonic acid, a component of myelin. HD pathogenesis also involves oxidative and inflammatory injury and EA exerts antioxidative and antiinflammatory efficacies including inhibition of thrombin and elastase. Consumption of rapeseed, indian mustard, and Canola oils (containing EA) improves cognitive parameters in animal models, as well as treatment with pure EA. Moreover, erucamide, an endogenous EA-amide derivative regulating angiogenesis and water balance, exerts antidepressive and anxiolytic effects in mice. Hitherto, no study has investigated the therapeutic potential of EA in HD and we believe that it strongly merits to be studied in animal models of HD as a potential therapeutic.