The Advancements and Prospects of Nervonic Acid Production

Five-month real-ambient PM2.5 exposure impairs learning in Brown Norway rats: Insights from multi omics-based analysis

PM2.5, recognized as a potential pathogenic factor for nervous system diseases, remains an area with many unknowns, particularly regarding its effects on human health. After five-month real-ambient PM2.5 exposure, we observed no significant pathological damage to the lung, liver, spleen, or kidney tissues. However, PM2.5 exposure led to neuronal degeneration in the hippocampal CA1 region of Brown Norway (BN) rats. The level of IL-6, IL-13, IL-1β, IL-12, IL-4, GRO/KC, MIP-1α, CM-CSF significantly increased in lung lavage fluid (P < 0.05 for all). Notably, we detected a slight impairment in spatial learning ability, as evidenced by the Barnes maze training outcomes. There were no significant changes in the bacterial community in lung lavage fluid (P = 0.621), but the bacterial community in the gut significantly changed (P < 0.001), with more species identified (P < 0.05). The metabolomic analysis revealed 147 and 149 significantly changed metabolites in the pulmonary system and serum, respectively (P < 0.05). PM2.5 exposure caused a decrease in Nervonic acid (NA) in both the lung and serum, which likely contributed to spatial learning impairment (P < 0.01). The correlation between lung metabolites, gut bacterial species, and serum metabolites indicated that PM2.5 exposure likely impaired spatial learning through the lung-gut-brain axis pathway. Lung and serum metabolic disorders and intestinal microbial imbalance occurred in BN rats post-five-month real-ambient PM2.5 exposure. There were two potential ways that PM2.5 exposure caused the decline of spatial learning ability in wild-type BN rats: (1) PM2.5 exposure led to a significant decrease of neuroprotective Nervonic acid in lung and serum metabolites. (2) PM2.5 exposure likely led to reduced spatial learning ability through the lung-gut-brain axis.

Integrated metabolome and microbiome strategy reveals the therapeutic effect of nervonic acid on Alzheimer's disease rats

Alzheimer's disease (AD) is a complex neurodegenerative disease. Nervonic acid is a component of breast milk and is also found in fish oil and specific vegetable oils. Studies have shown that nervonic acid is essential for the development of the human nervous system. In this study, Morris water maze (MWM) test and pathological analysis showed that nervonic acid could improve cognitive deficits and brain nerve damage in AD rats. Then, through sequencing, we found that nervonic acid increased the abundance of beneficial bacteria such as Lactobacillus and Bacteroides, and decreased the abundance of Pseudomonadaceae_Pseudomonas. Not only that, nervonic acid also regulates the production of short-chain fatty acids (SCFA) and the levels of 29 fecal metabolites, and affects the metabolism of linoleic acid, α-linolenic acid, arachidonic acid, and sphingolipid. Finally, we verified the regulatory effect of nervonic acid on metabolic enzyme activity.

In silico characterization of Rhodotorula toruloides ELO-like elongases and production of very-long-chain fatty acids by expressing Rtelo2, RtKCR, RtHCD, and RtECR through IRES-mediated bicistrons

Rhodotorula toruloides, an oleaginous yeast known for its high lipid productivity, produces lipids with low very-long-chain fatty acid (VLCFA) content. Meanwhile, the roles of enzymes, particularly the condensing enzymes, involved in VLCFA biosynthesis in R. toruloides remained unclear. In this study, two elongases, RtELO1 and RtELO2, were identified from R. toruloides U13N3 and their tertiary structure and catalytic mechanism were investigated using molecular dynamic methods. Both enzymes exhibited typical ELO-like characteristics, with active sites located within cavities formed by seven transmembrane helixes. RtELO2 displayed higher binding affinity to acyl-CoAs compared to RtELO1, and at least seven amino acid residues, including two crucial histidines in the "HXXHH" box, were identified as important for the condensation reaction. To enhance VLCFA production, an internal ribosome entry site (IRES)-mediated bicistronic strategy was developed to integrate multiple genes into the R. toruloides genome. The efficiency of IRES-mediated translation initiation reached 85.4% of cap-dependent upstream translation, based on EGFP fluorescent intensity. Using this strategy, four genes encoding enzymes involved in the VLCFA biosynthesis cycle (Rtelo2, RtKCR, RtHCD, and RtECR) were introduced into the U13N3 genome in various combinations. The results indicated that the expression of a single elongase had a modest effect on VLCFA production, but the simultaneous expression of multiple genes resulted in cumulative effects. Notably, the transformant harboring four genes exhibited a remarkable 436.8% increase in C22 and C24 VLCFA yield compared to the original strain.

Euonymus maximowiczianus aril-derived long-term suspension-cultured cells: Light and methyl jasmonate impact in the anthocyanin and VLCFA accumulation

The genus Euonymus (L.) consists of shrubs and woody plants, distributed mainly in the Northern Hemisphere. Several hundred of secondary metabolites have been isolated from Euonymus spp. In addition, fatty oil was found in the fruits of some Euonymus spp., which accumulates not only in the seeds but also in the arils. This study presents the research of unique over ten-year-old suspension cell cultures of the endemic plant Euonymus maximoviczianus Prokh., obtained from the aril tissue of unripe capsules. The suspension cells retain the ability to form oil droplets containing neutral lipids. Both cells growing in the dark (Em-D culture) and cells growing in the light (Em-L culture) can synthesize very-long-chain fatty acids (VLCFAs) as well as cyanidin-3-O-hexoside, delphinidin-3-O-hexoside, and peonidin-3-O-hexoside. Here, we researched the VLCFA and anthocyanin accumulation dynamics during subcultivation, as well as the influence of methyl jasmonate (MeJA) and light on these processes. In the darkness, the formation of VLCFAs was more intense, while the biosynthesis of anthocyanins was significantly activated in the light. In Em-L cells, more than 76% of anthocyanins were represented by cyanidin-3-O-hexoside, and in Em-D cells delphinidin-3-O-hexoside was more actively synthesized (45%). MeJA substantially enhanced the accumulation of anthocyanins (especially in the light) and, surprisingly, the formation of VLCFAs in both Em-L and Em-D cell cultures. The possible competition between the biosynthetic pathways of VLCFAs and anthocyanins is discussed in connection with the commonality of the cytosolic pool of their precursor, malonyl-CoA.

Domestication and engineering of pennycress (Thlaspi arvense L.): challenges and opportunities for sustainable bio-based feedstocks

MAIN CONCLUSION

Pennycress, as an emerging oilseed crop with high oil content, faces challenges but offers potential for sustainable bioproducts; ongoing research aims to enhance its traits and quality. Pennycress (Thlaspi arvense L.) is an emerging oilseed crop with many advantages, such as high seed oil (27-39%) and monounsaturated fatty acid (55.6%) content, making it an attractive candidate to produce sustainable bioproducts. However, several challenges are associated with domesticating pennycress, including high silicle shatter, which reduces seed yield during harvest, non-uniformed germination rate and high contents of erucic acid and glucosinolates, which have adverse health effects on humans and animals. Pennycress, which can be easily and rapidly transformed using the floral dip method under vacuum, can achieve trait improvements. Ongoing research for pennycress domestication using mutation breeding, including ethylmethylsulfonate treatment and genome editing, aims to improve its quality. Pennycress can be used as an excellent platform for producing industrially important fatty acids such as hydroxy and epoxy fatty acids and docosahexaenoic acid. In conclusion, pennycress is a promising oilseed crop with multiple advantages and potential applications. Continuous improvements in quality and engineering for producing high-value bio-based feedstocks in pennycress will establish it as a sustainable and economically valuable crop.

Protective effect of water-soluble nervonic acid micro-powder coated with chitosan oligosaccharide and silk fibroin on hippocampal neuronal HT22 cells

Nervonic acid (NA) is an extremely long chain monounsaturated fatty acid that plays a crucial biological role in brain development and repair. However, its low solubility reduced bioavailability and limited its applications. In this study, spherical water-soluble nervonic acid composite micro-powder (NA-WM) was constructed by layer-by-layer self-assembly technology under electrostatic interaction and hydrogen bond, in which electronegative NA was used as the core material, and electropositive COS (Chitosan oligosaccharide) with neuroprotective properties and electronegative SF (Silk fibroin) with biocompatibility and anti-inflammatory synergism were used as the wall material. In the preparation process, the electronegative NA was first combined with electropositive COS by antisolvent method, and then the electropositive COS-NA complex was encapsulated with electronegative SF to form NA-WM. The optimal preparation conditions were screened and optimized via single-factor and BBD method. Under the optimum conditions, the average particle size of NA-WM was 420 ± 35 nm. The results of TGA (Thermogravimetric), SEM (Scanning electron microscopy), and FTIR (Fourier transform infrared spectroscopy) confirmed that NA-WM had good thermal stability and spherical-defined layer-to-layer structure. Additionally, at pH 1.5, the NA release rate of NA-WM was as high as 89.54 % within 2.5 h. Through measuring the levels of MDA (Malondialdehyde), CAT (Catalase), SOD (Superoxide dismutase), GSH-Px (Glutathione peroxidase), and LDH (Lactate dehydrogenase), as well as flow cytometry and SEM analysis, it was confirmed that NA-WM could protect Aβ1-42-induced HT22 by inhibiting oxidative stress and reducing mitochondrial membrane potential. This study provided data support for the development and application of NA.

3-ketoacyl-CoA synthase 7 from Xanthoceras sorbifolium seeds is a crucial regulatory enzyme for nervonic acid biosynthesis

Nervonic acid (C24:1) is a very-long-chain fatty acid that plays an imperative role in human brain development and other health benefits. In plants, 3-ketoacyl-CoA synthase (KCS) is the key rate-limiting enzyme for C24:1 biosynthesis. Xanthoceras sorbifolium is a valuable oil-producing economic woody species with abundant C24:1 in seed oils, but the key KCS gene responsible for C24:1 accumulation remains unknown. In this work, a correlation analysis between the transcript profiles of KCS and dynamic change of C24:1 content in developing seeds of X. sorbifolium were conducted to screen out three members of KCS, namely XsKCS4, XsKCS7 and XsKCS8, potentially involved in C24:1 biosynthesis. Of which, the XsKCS7 was highly expressed in developing seeds, while XsKCS4 and XsKCS8 displayed the highest expression in fruits and flowers, respectively. Overexpression of XsKCS4, XsKCS7 and XsKCS8 in yeast Saccharomyces cerevisiae and plant Arabidopsis thaliana indicated that only XsKCS7 possessed the ability to facilitate the biosynthesis of C24:1. These findings collectively suggested that XsKCS7 played a crucial role in specific regulation of C24:1 biosynthesis in X. sorbifolium seeds.

Study on the Extraction of Nervonic Acid from the Oil of Xanthoceras sorbifolium Bunge Seeds

Seven fatty acids were detected by GC-MS in Xanthoceras sorbifolium Bunge seed oil extracted at different temperatures, including Palmitic acid C16:0, Stearic acid C18:0, Oleic acid C18:1, Eicosenoic acid C20:1, Docosenoic acid C22:1, Tetracosenoic acid C24:1, and Linoleic acid C18:2. The highest content of nervonic acid (NA) was found in Xanthoceras sorbifolium Bunge seed oil extracted at 70 °C. Three methods were selected to analyze the extraction rate of nervonic acid in Xanthoceras sorbifolium Bunge seed oil, including urea complexation, low-temperature solvent crystallization, and a combined treatment using these two methods. The final content of nervonic acid obtained was 14.07%, 19.66%, and 40.17%, respectively. The combined treatment method increased the purity of nervonic acid in Xanthoceras sorbifolium Bunge seed oil by 12.62 times. Meanwhile, thermogravimetric behavior analysis of samples extracted using different methods was conducted by thermogravimetric analyzer, which suggested that the thermal stability of the samples extracted by the combined treatment was enhanced. These results can provide a new process parameter and scientific basis for the extraction of NA. At the same time, FTIR and NMR were also used to characterize the combined extraction sample, and the structure of the samples was proved.

Effects of cold acclimation on serum biochemical parameters and metabolite profiles in Schizothorax prenanti

BACKGROUND

Environmental temperature is critical in regulating biological functions in fish. S. prenanti is a kind of cold-water fish, but of which we have little knowledge about the metabolic adaptation and physiological responses to long-term cold acclimation.

RESULTS

In this study, we determined the physiological responses of S. prenanti serum after 30 days of exposure to 6℃. Compared with the control group, the levels of TC, TG, and LDL-C in the serum were significantly (P < 0.05) increased, and the level of glucose was significantly (P < 0.05) decreased under cold acclimation. Cold acclimation had no effect on the gene expression of pro-inflammatory factors and anti-inflammatory factors of S. prenanti. Metabolomics analysis by LC-MS showed that a total of 60 differential expressed metabolites were identified after cold acclimation, which involved in biosynthesis of amino acids, biosynthesis of unsaturated fatty acids, steroid degradation, purine metabolism, and citrate cycle pathways.

CONCLUSION

The results indicate that cold acclimation can alter serum metabolites and metabolic pathways to alter energy metabolism and provide insights for the physiological regulation of cold-water fish in response to cold acclimation.

Dietary Supplementation with Nervonic Acid Ameliorates Cerebral Ischemia-Reperfusion Injury by Modulating of Gut Microbiota Composition-Fecal Metabolites Interaction

SCOPE

Cerebral ischemia-reperfusion (IR) injury stands as a prominent global contributor to disability and mortality. Nervonic acid (NA), a bioactive elongated monounsaturated fatty acid, holds pivotal significance in human physiological well-being. This research aims to explore the prophylactic effects and fundamental mechanisms of NA in a rat model of cerebral IR injury.

METHODS AND RESULTS

Through the induction of middle cerebral artery occlusion, this study establishes a rat model of cerebral IR injury and comprehensively assesses the pharmacodynamic impacts of NA pretreatment. This evaluation involves behavioral analyses, histopathological examinations, and quantification of serum markers. Detailed mechanisms of nervonic acid's prophylactic effects are revealed through fecal metabolomics and 16S rRNA sequencing analyses. Our findings robustly support nervonic acid's capacity to ameliorate neurological impairments in rats afflicted with cerebral IR injury. Beyond its neurological benefits, NA demonstrates its potential by rectifying metabolic perturbations across diverse pathways, particularly those pertinent to unsaturated fatty acid metabolism. Additionally, NA emerges as a modulator of gut microbiota composition, notably by selectively enhancing vital genera like Lactobacillus.

CONCLUSION

These comprehensive findings highlight the potential of incorporating NA as a functional component in dietary interventions aimed at targeting cerebral IR injury.

Acer truncatum Bunge seed oil ameliorated oxaliplatin-induced demyelination by improving mitochondrial dysfunction via the Pink1/Parkin mitophagy pathway

Dietary nutritional support for special populations is an effective and feasible method to improve the quality of life of patients and reduce medical pressure. Acer truncatum Bunge seed oil (ATSO) is widely recognized for its ability to promote nerve myelin regeneration. To evaluate the ameliorative effects of ATSO on chemotherapy-induced demyelination, a zebrafish model of chemotherapy-induced demyelination was established. The results showed that 100 μg mL-1 of ATSO reversed tail morphology damage, axon degeneration, touch response delay, ROS level upregulation and the expression of myelin basic protein decrease in chemotherapy-induced zebrafish. In addition, the expression of myelin markers (including sox10, krox20, and pmp22) in oxaliplatin-induced cells was markedly reversed by ATSO and its active components (gondoic acid, erucic acid, and nervonic acid). ATSO and its active components could reverse demyelination by ameliorating mitochondrial dysfunction. Conversely, linoleic acid and linolenic acid promoted demyelination by exacerbating mitochondrial dysfunction. Moreover, the Pink1/Parkin pathway was recognized as the main reason for ATSO and its active components improving mitochondrial function by activating mitophagy and restoring autophagic flow. Taken together, this study demonstrated that ATSO and its active components could be further developed as novel functional food ingredients to antagonize demyelination.

Metabolic engineering of oleaginous yeast in the lipogenic phase enhances production of nervonic acid

Insufficient biosynthesis efficiency during the lipogenic phase can be a major obstacle to engineering oleaginous yeasts to overproduce very long-chain fatty acids (VLCFAs). Taking nervonic acid (NA, C24:1) as an example, we overcame the bottleneck to overproduce NA in an engineered Rhodosporidium toruloides by improving the biosynthesis of VLCFAs during the lipogenic phase. First, evaluating the catalytic preferences of three plant-derived ketoacyl-CoA synthases (KCSs) rationally guided reconstructing an efficient NA biosynthetic pathway in R. toruloides. More importantly, a genome-wide transcriptional analysis endowed clues to strengthen the fatty acid elongation (FAE) module and identify/use lipogenic phase-activated promoter, collectively addressing the stagnation of NA accumulation during the lipogenic phase. The best-designed strain exhibited a high NA content (as the major component in total fatty acid [TFA], 46.3%) and produced a titer of 44.2 g/L in a 5 L bioreactor. The strategy developed here provides an engineering framework to establish the microbial process of producing valuable VLCFAs in oleaginous yeasts.

Comparative Analysis of Key Odorants and Aroma Characteristics in Hot-Pressed Yellow Horn (Xanthoceras sorbifolia bunge) Seed Oil Via Gas Chromatography-Ion Mobility Spectrometry and Gas Chromatography-Olfactory-Mass Spectrometry

Volatile compounds (VOCs) present in the oil extracted from yellow horn seeds were first analyzed using GC-IMS and GC-O-MS at varying roasting temperatures. A total of 97 VOCs were detected using GC-IMS, while 77 were tentatively identified using GC-O-MS. Moreover, both methods allowed the identification of 24 VOCs, of which the type of aldehydes is the most abundant. Combining the results of GC-IMS, GC-O-MS, OAVs, and VIP, it was concluded that hexanal, 2,5-dimethylpyrazine, heptanal, 2-pentylfuran, 1-hexanol, and 1-octen-3-ol were the key aroma compounds. The PLS-DA and OPLS-DA models have demonstrated the ability to discriminate between different oil roasting temperatures with high accuracy. The roasting temperature of 160 °C was found to yield the highest content of main aroma substances, indicating its optimality for yellow horn seed oil production. These findings will prove beneficial for optimizing industrial production and enhancing oil aroma control.

Combining orthogonal plant and non-plant fatty acid biosynthesis pathways for efficient production of microbial oil enriched in nervonic acid in Yarrowia lipolytica

Nervonic acid has proven efficacy in brain development and the prevention of neurodegenerative diseases. Here, an alternative and sustainable strategy for nervonic acid-enriched plant oil production was established. Different β-ketoacyl-CoA synthases and heterologous Δ15 desaturase were co-expressed, combined with the deletion of the β-oxidation pathway to construct orthogonal plant and non-plant nervonic acid biosynthesis pathways in Yarrowia lipolytica. A "block-pull-restrain" strategy was further applied to improve the supply of stearic acid as the precursor of the non-plant pathway. Then, lysophosphatidic acid acyltransferase from Malania oleifera (MoLpaat) was identified, which showed specificity for nervonic acid. Endogenous LPAAT was exchanged by MoLPAAT resulted in 17.10 % nervonic acid accumulation. Finally, lipid metabolism was engineered and cofactor supply was increased to boost the lipid accumulation in a stable null-hyphal strain. The final strain produced 57.84 g/L oils with 23.44 % nervonic acid in fed-batch fermentation, which has the potential to substitute nervonic acid-enriched plant oil.

Nervonic acid and its sphingolipids: Biological functions and potential food applications

Nervonic acid, a 24-carbon fatty acid with only one double bond at the 9th carbon (C24:1n-9), is abundant in the human brain, liver, and kidney. It not only functions in free form but also serves as a critical component of sphingolipids which participate in many biological processes such as cell membrane formation, apoptosis, and neurotransmission. Recent studies show that nervonic acid supplementation is not only beneficial to human health but also can improve the many medical conditions such as neurological diseases, cancers, diabetes, obesity, and their complications. Nervonic acid and its sphingomyelins serve as a special material for myelination in infants and remyelination patients with multiple sclerosis. Besides, the administration of nervonic acid is reported to reduce motor disorder in mice with Parkinson's disease and limit weight gain. Perturbations of nervonic acid and its sphingolipids might lead to the pathogenesis of many diseases and understanding these mechanisms is critical for investigating potential therapeutic approaches for such diseases. However, available studies about this aspect are limited. In this review, relevant findings about functional mechanisms of nervonic acid have been comprehensively and systematically described, focusing on four interconnected functions: cellular structure, signaling, anti-inflammation, lipid mobilization, and their related diseases.