Triacylglyceride Accumulation Research Articles

Virgin flaxseed oil supplemented or not with tocopherols and phytosterols prevents liver steatosis induced by high‐fat diets in male Wistar rats

AbstractThis study aimed to investigate the effect of a virgin flaxseed oil (FO) rich in n − 3 polyunsaturated fatty acid, supplemented or not with a bioactive supplement (BS) containing tocopherols and phytosterols on the prevention of nonalcoholic fatty liver disease in a high‐fat (HF) animal model. Male Wistar rats were fed 60 days with a recommended (SO7, soybean oil 7%) or an HF diet (fat, 30%) containing soybean (SO30), corn (CO30), or FO (FO30) or the same oils supplemented with 1% of BS (SO30BS, CO30BS, or FO30BS, respectively). Hepatic and dietary FA composition, triacylglycerides (TAGs) content in serum and liver, nutritional parameters, in vivo TAG‐secretion rate, liver histology, mRNA levels of β‐oxidation‐related genes, and carnitine palmitoyl transferase‐1a (CPT‐1a) enzyme activity were determined. At HF levels, FO30 and FO30BS groups showed the highest total n − 3 PUFA levels in diets and were associated with lower weight gain, liver TAG content, and microsteatosis degree. The CPT‐1a activity was enhanced in FO30 and FO30BS, showing differences only by the type of dietary oil. The BS supplementation induced an increase in the β‐oxidation‐related gene expression. Virgin FO prevented liver steatosis and hepatomegaly induced by HF diets. The BS supplementation reduced body fat accumulation and enhanced expression of β‐oxidation related genes, without affecting hepatic TAG content.Practical Applications: Scientific knowledge of functional lipids with high oxidative stability and biological activity has great practical application in reducing non‐communicable chronic diseases. This study provides evidence on the potential synergic and complementary effects of virgin FO, TP, and PS to be used for the prevention of the metabolic hepatic disorders involved during the evolution of the different steps of NAFLD. Specifically, based on different biological mechanisms, this stable combination of bioactive lipids could prevent not only the development of exacerbated hepatic TAG accumulation but also the hepatocellular injury seen at different stages from hepatic steatosis to steatohepatitis.

Polyphenolics extracts from Ascophyllum nodosum protect against ultraviolet B-induced oxidative damage in mouse retinal Müller cells

Long-term exposure to sunlight, especially ultraviolet (UV), induces eye injury in people. We investigated the protective potential of Polyphenolic extract from Ascophyllum nodosum (PEAn) against UV-B-induced oxidative damage in retinal Müller cells (RMCs). In the UV-B-induced damage model of RMCs, PEAn demonstrated a potent photoprotective effect that reduced oxidative damage and apoptosis. PEAn significantly regulated the concentrations of ROS, Caspase-3, and Calcium ions (Ca2+) in RMCs generated by UV-B. The mitochondrial membrane potential (ΔΨm) and activities of various antioxidant enzymes (SOD, CAT, and GSH-Px) were significantly increased, whereas the MDA was reduced. Lipidomic research in RMCs also revealed that UV-B irradiation significantly altered the lipid compounds in the cells, while PEAn therapy gradually restored normal cells. Both the accumulation of triacylglycerides and the toxicity of the lipids in RMCs were simultaneously reduced by PEAn. The findings indicated that PEAn could be a potential natural photochemical protectant against UV-B-induced oxidative damage.

Prdm16 mutation determines sex-specific cardiac metabolism and identifies two novel cardiac metabolic regulators.

Mutation of the PRDM16 gene causes human dilated and non-compaction cardiomyopathy. The PRDM16 protein is a transcriptional regulator that affects cardiac development via Tbx5 and Hand1, thus regulating myocardial structure. The biallelic inactivation of Prdm16 induces severe cardiac dysfunction with post-natal lethality and hypertrophy in mice. The early pathological events that occur upon Prdm16 inactivation have not been explored. This study performed in-depth pathophysiological and molecular analyses of male and female Prdm16csp1/wt mice that carry systemic, monoallelic Prdm16 gene inactivation. We systematically assessed early molecular changes through transcriptomics, proteomics, and metabolomics. Kinetic modelling of cardiac metabolism was performed in silico with CARDIOKIN. Prdm16csp1/wt mice are viable up to 8 months, develop hypoplastic hearts, and diminished systolic performance that is more pronounced in female mice. Prdm16csp1/wt cardiac tissue of both sexes showed reductions in metabolites associated with amino acid as well as glycerol metabolism, glycolysis, and the tricarboxylic acid cycle. Prdm16csp1/wt cardiac tissue revealed diminished glutathione (GSH) and increased inosine monophosphate (IMP) levels indicating oxidative stress and a dysregulated energetics, respectively. An accumulation of triacylglycerides exclusively in male Prdm16csp1/wt hearts suggests a sex-specific metabolic adaptation. Metabolic modelling using CARDIOKIN identified a reduction in fatty acid utilization in males as well as lower glucose utilization in female Prdm16csp1/wt cardiac tissue. On the level of transcripts and protein expression, Prdm16csp1/wt hearts demonstrate an up-regulation of pyridine nucleotide-disulphide oxidoreductase domain 2 (Pyroxd2) and the transcriptional regulator pre-B-cell leukaemia transcription factor interacting protein 1 (Pbxip1). The strongest concordant transcriptional up-regulation was detected for Prdm16 itself, probably through an autoregulatory mechanism. Monoallelic, global Prdm16 mutation diminishes cardiac performance in Prdm16csp1/wt mice. Metabolic alterations and transcriptional dysregulation in Prdm16csp1/wt affect cardiac tissue. Female Prdm16csp1/wt mice develop a more pronounced phenotype, indicating sexual dimorphism at this early pathological window. This study suggests that metabolic dysregulation is an early event in the PRDM16 associated cardiac pathology.

Novel Insight of Nitrogen Deprivation Affected Lipid Accumulation by Genome-Wide Lactylation in Nannochloropsis oceanica.

Lysine lactylation (kla) as a post-translational modification (PTM) is linked to chromatin remodeling and gene transcription. Nitrogen stress can induce triacylglyceride (TAG) accumulation in most microalgae. To reveal lipid synthesis from another layer, the 4D label-free proteome method was used to track lactylation modifications and protein expression profiles after 3 days of nitrogen deprivation in Nannochloropsis oceanica to analyze the function and prevalence of lactylation. Under nitrogen deprivation (ND) and nitrogen repletion (NR) cultivation conditions, we mapped the proteome and lactylome of proliferating microalgal cells. The results showed that there were 5203 proteins identified and 1245 proteins differentially expressed; among them, 664 were upregulated and 581 were downregulated. The N. oceanica strain also has a total of 868 lactylation sites, which were found on 379 proteins. The lactylated proteins were linked to biological activities as diverse as lipid metabolism, carbon fixation, photosynthesis, glycolysis, and the tricarboxylic acid (TCA) cycle and were found in various subcellular compartments. Under ND, 414 specific lactylation sites were found in 252 proteins. More interestingly, under ND vs NR, lactylation showed a significantly upregulated trend. This study provides a foundation for the future epigenetic enhancement of microalgal cells by providing the first dataset of lactylome in Nannochloropsis.

Characterization of nongxiang- and soy sauce-type distilled grains and their application in enhancing polyunsaturated fatty acid and triacylglyceride production from Chlorella sp. 038F

A sustainable method of handling large quantities of distilled grains in the Chinese baijiu industry is bioconverting these distilled grains into value-added products. We here compared the properties of two distilled grains, soy sauce-type (DGSB) and nongxiang-type (DGNB). Results revealed that DGSB had higher contents of crude protein, crude fat, soluble sugars, free amino acids, and antioxidants than DGNB. Mixotrophic cultivation of Chlorella sp. 038F was performed using aqueous crude extracts of distilled grains. Biomass, total lipid, and fatty acid production with DGSB crude extracts was approximately 2.43, 1.40, and 1.69 times higher than that with photoautotrophic culture, respectively, whereas DGNB crude extracts only improved the biomass by 1.64 times. Detailed profile analysis revealed that DGSB crude extracts remarkably increased the proportions of polyunsaturated fatty acids, especially linoleic and α-linolenic acids, and triacylglycerides in total lipids. Interestingly, DGNB crude extracts did not enhance total lipid accumulation but increased triacylglyceride accumulation. Comparative transcriptomics revealed that genes encoding photosynthetic pigments and proteins were downregulated, suggesting the decreased anabolism of the photosynthetic light reaction. Genes involved in fatty acid biosynthesis, the Calvin cycle, and glycolysis were upregulated, indicating sufficient accumulation of the building blocks acyl-CoA and glycerol-3-phosphate for triacylglyceride biosynthesis. All transcriptional trends of triacylglyceride biosynthesis-related genes were consistent with the triacylglyceride accumulation patterns. This study provides insights into the potential use of microalgae for the bioconversion of distilled grains into high-value products and highlights the role of distilled grains in improving polyunsaturated fatty acid and triacylglyceride production.

Plant Pyranocoumarins: Description, Biosynthesis, Application.

This overview article contains information about pyranocoumarins over the last 55 years. The article is based on the authors' phytochemical and physiological studies in vivo and in vitro as well as search and analysis of data in literature available on Google Scholar, Web of Science, PubMed, and ScienceDirect before January 2022. Pyranocoumarins are synthesized in plants of the Apiaceae, Rutaceae families, and one species in each of the Cornaceae, Calophyllaceae, and Fabaceae families can synthesize this class of compounds. The physiological role of these compounds in plants is not clear. It has been proven that these substances have a wide range of biological activities: anti-cancer, anti-spasmatic, and anticoagulant, and they also inhibit erythrocyte lysis and accumulation of triacylglycerides. The overview generalizes the modern understanding of the classification, structure, and biological activity of natural pyranocoumarins, and summarizes dispersed data into a unified scheme of biosynthesis. The review analyzes data on the localization and productivity of these substances in individual organs and the whole plant. It discusses a link between the unique structure of these substances and their biological activity, as well as new opportunities for pyranocoumarins in pharmacology. The article evaluates the potential of different plant species as producers of pyranocoumarins and considers the possibilities of cell cultures to obtain the end product.

In vivo functional characterization of EGFR variants identifies novel drivers of glioblastoma.

Glioblastoma is the most common and aggressive primary brain tumor. Large-scale sequencing initiatives have cataloged its mutational landscape in hopes of elucidating mechanisms driving this deadly disease. However, a major bottleneck in harnessing this data for new therapies is deciphering "driver" and "passenger" events amongst the vast volume of information. We utilized an autochthonous, in vivo screening approach to identify driver, EGFR variants. RNA-Seq identified unique molecular signatures of mouse gliomas across these variants, which only differ by a single amino acid change. In particular, we identified alterations to lipid metabolism, which we further validated through an unbiased lipidomics screen. Our screen identified A289I as the most potent EGFR variant, which has previously not been characterized. One of the mechanisms through which A289I promotes gliomagenesis is to alter cellular triacylglycerides through MTTP. Knockout of Mttp in mouse gliomas, reduces gliomagenesis in multiple models. EGFR variants that differ by a single amino acid residue differentially promote gliomagenesis. Among the identified mechanism that drives glioma growth include lipid metabolism through MTTP. Understanding triacylglyceride accumulation may present a prospective therapeutic pathway for this deadly disease.

Low Birth Weight Intensifies Changes in Markers of Hepatocarcinogenesis Induced by Fructose Consumption in Rats.

Intrauterine growth restriction (IUGR) due to fetal exposure to glucocorticoid excess results in metabolic inflexibility and hepatic steatosis upon nutritional stress during adulthood. We previously demonstrated that rats born to dexamethasone (DEX)-treated mothers developed hepatic steatosis when exposed to 10% fructose solution during adult life. Persistent triacylglyceride (TAG) accumulation in the liver, in turn, is a feature of non-alcoholic fatty liver disease (NAFLD), which serves as a risk factor for non-alcoholic steatohepatitis (NASH) and hepatocellular carcinoma (HCC). In the present study, we demonstrate that the combination of IUGR and fructose treatment during adulthood also results in increased hepatic myeloperoxidase (MPO) activity, AKT phosphorylation and serum aspartate transaminase. Growth-restricted rats also presented reduced hepatic TRIB3 and GADD45a after fructose treatment. Other markers of cell proliferation, such as Cyclin D, PCNA, Hgf and Hspa4/Hsp70 expression and the number of Ki-67 positive cells, were all increased in the liver of growth- restricted rats treated with fructose. On the other hand, the combination of IUGR and fructose treatment during adult life reduced the levels of IGF-1. In conclusion, our data indicate that after exposure to fructose, adult rats subjected to dexamethasone-induced IUGR display exacerbated molecular changes in markers of NASH and HCC.

RNA-seq analysis reveals genes related to photosynthetic carbon partitioning and lipid production in Phaeodactylum tricornutum under alkaline conditions.

Alkaline pH can induce triacylglyceride accumulation in microalgae, however its molecular mechanism remains elusive. Here, we investigated the effect of 2-[N-cyclohexylamino]-ethane-sulfonic acid (CHES) -induced intracellular alkalization on the lipid production in Phaeodactylum tricornutum. Intracellular pH was increased upon CHES treatment, displaying a high BCECF fluorescence ratio. CHES treatment significantly induced lipid accumulation but had no change in cell density and biomass. The expression of genes involved in photoreaction, carbon fixation, glycolysis, pentose phosphate pathway, amino acid catabolism, GS/GOGAT cycle, TCA cycle, triacylglyceride assembly, de novo fatty acid synthesis were up-regulated, while that in amino acid biosynthesis were down-regulated under CHES conditions. Correspondingly, the activity of phosphoribulokinase, carbonic anhydrase, pyruvate dehydrogenase and acetaldehyde dehydrogenase were enhanced by CHES treatment. Chloroplast-specific biological processes were activated by CHES treatment in P. tricornutum, which redirects the flux of carbon into lipid biosynthesis, meanwhile stimulates de novo fatty acid biosynthesis, leading to lipid accumulation under CHES conditions. These indicate an enhancement of intermediate metabolism, resulting in lipid accumulation by CHES.

Structure of fungal communities in sequencing batch reactors operated at different salinities for the selection of triacylglyceride-producers from a fish-canning lipid-rich waste stream

Oleaginous fungi natively accumulate large amounts of triacylglycerides (TAG), widely used as precursors for sustainable biodiesel production. However, little attention has been paid to the diversity and roles of fungal mixed microbial cultures (MMCs) in sequencing batch reactors (SBR). In this study, a lipid-rich stream produced in the fish-canning industry was used as a substrate in two laboratory-scale SBRs operated under the feast/famine (F/F) regime to enrich microorganisms with high TAG-storage ability, under two different concentrations of NaCl (SBR-N: 0.5 g/L; SBR-S: 10 g/L). The size of the fungal community in the enriched activated sludge (EAS) was analyzed using 18S rRNA-based qPCR, and the fungal community structure was determined by Illumina sequencing. The different selective pressures (feeding strategy and control of pH) implemented in the enrichment SBRs throughout operation increased the abundance of total fungi. In general, there was an enrichment of genera previously identified as TAG-accumulating fungi (Apiotrichum, Candida, Cutaneotrichosporon, Geotrichum, Haglerozyma, Metarhizium, Mortierella, Saccharomycopsis, and Yarrowia) in both SBRs. However, the observed increase of their relative abundances throughout operation was not significantly linked to a higher TAG accumulation.

The Liver and Heart: How the Two Most Beloved “Babies” in the Human Body Communicate

The Liver and Heart: How the Two Most Beloved “Babies” in the Human Body Communicate

Complementary Lipidomic, Proteomic, and Mass Spectrometry Imaging Approach to the Characterization of the Acute Effects of Radiation in the Non-human Primate Mesenteric Lymph Node after Partial-body Irradiation with Minimal Bone Marrow Sparing.

Radiation sequelae is complex and characterized by multiple pathologies, which occur over time and nonuniformly throughout different organs. The study of the mesenteric lymph node (MLN) due to its importance in the gastrointestinal system is of particular interest. Other studies have shown an immediate post-irradiation reduction in cellularity due to the known effects of irradiation on lymphoid cell populations, but the molecular and functional mechanisms that lead to these cellular alterations remain limited. In this work, we show the use of lipidomic, proteomic, and mass spectrometry imaging in the characterization of the effects of acute radiation exposure on the MLN at different time points after ionizing radiation (IR) from 4 d to 21 d after 12 Gy partial body irradiation with 2.5% bone marrow sparing. The combined analyses showed a dysregulation of the lipid and protein composition in the MLN after IR. Protein expression was affected in numerous pathways, including pathways regulating lipids such as LXR/RXR activation and acute phase response. Lipid distribution and abundance was also affected by IR in the MLN, including an accumulation of triacylglycerides, a decrease in polyunsaturated glycerophospholipids, and changes in polyunsaturated fatty acids. Those changes were observed as early as 4 d after IR and were more pronounced for lipids with a higher concentration in the nodules and the medulla of the MLN. These results provide molecular insight into the MLN that can inform on injury mechanism in a non-human primate model of the acute radiation syndrome of the gastrointestinal tract. Those findings may contribute to the identification of therapeutic targets and the development of new medical countermeasures.

Cadaverine regulates biotin synthesis to modulate primary root growth in Arabidopsis.

SUMMARYCadaverine, a polyamine, has been linked to modification of root growth architecture and response to environmental stresses in plants. However, the molecular mechanisms that govern the regulation of root growth by cadaverine are largely unexplored. Here we conducted a forward genetic screen and isolated a mutation, cadaverine hypersensitive 3 (cdh3), which resulted in increased root‐growth sensitivity to cadaverine, but not other polyamines. This mutation affects the BIO3‐BIO1 biotin biosynthesis gene. Exogenous supply of biotin and a pathway intermediate downstream of BIO1, 7,8‐diaminopelargonic acid, suppressed this cadaverine sensitivity phenotype. An in vitro enzyme assay showed cadaverine inhibits the BIO3‐BIO1 activity. Furthermore, cadaverine‐treated seedlings displayed reduced biotinylation of Biotin Carboxyl Carrier Protein 1 of the acetyl‐coenzyme A carboxylase complex involved in de novo fatty acid biosynthesis, resulting in decreased accumulation of triacylglycerides. Taken together, these results revealed an unexpected role of cadaverine in the regulation of biotin biosynthesis, which leads to modulation of primary root growth of plants.

A transcriptional journey from sucrose to endosperm oil bodies in triple transgene oily wheat grain

Transgenic wheat expressing Wrinkled1 (Wri1), diacylglycerol acyltransferase 1 (DGAT1), and Oleosin genes with endosperm active promoters, in the companion paper were found to accumulate 5–10 times the quantity of triacylglyceride (TAG) in the endosperm compared to the control. In this study we track the pleiotropic effects on transcription at four grain development time points, of genes whose products are involved in the various pathways from sugar import to oil body formation, as well as other major metabolic pathways in the developing grain. The transcriptional impacts were substantial with early increases in genes for sucrose transport, hexose phosphate formation, cytoplasmic glycolysis, and ADP-glucose transport to the plastid. Corresponding to the late expression of the Wrinkled1 transgene, there was a late up-regulation of the entire suite of genes in the plastidial fatty acid synthesis pathway. Transport of fatty acid precursors to the ER was likely facilitated by early up-regulation of FAX1 (Fatty acid export) and LACS8 (long-chain acyl-CoA synthetase) genes. With the exception of the transgenic DGAT1, there were relatively few and moderate changes to transcription of other genes involved in TAG assembly in the ER, although the direct use of the acyl-PC pool appears to be down-regulated. A large up-regulation was observed at the three earliest time points of many genes associated with the formation of lipid droplets, including endogenous oleosins, caleosins, stereoleosins, seipins, and a variety of other lipid body associated proteins. Also unanticipated was the early down-regulation of a number of genes whose products are involved in lipid body turnover and peroxisomal β-oxidation of released fatty acids. Despite the substantial increase in TAG accumulation, the transgenic grains were not reduced in starch or protein and the transcriptional analysis demonstrated an early up-regulation of the entire suite of starch synthesis genes and protein storage genes.

Effects of Sex-Specific Gene on the Adipogenic Differentiation in 3T3-L1 Preadipocytes

ObjectivesGlobal statistics indicated that women are more likely to be obese than men, while sex and gender differences have been largely ignored in scientific reports which have caused serious biases in research conclusions. Previously, we have identified female-specific genes including NPR3 (natriuretic peptide receptor 3) in adipose tissue of obese mice by bioinformatics analysis. Here, we further investigated sex-specific effects of the NPR3 gene on the adipogenic differentiation in 3T3-L1 preadipocytes to understand the underlying mechanisms for sex differences. Methods3T3-L1 preadipocytes were treated with/without 1 μM fulvestrant (FUL, estrogen receptor antagonist) and/or 100 nM AP811 (NPR3 antagonist) during the early stage of differentiation. After cell differentiation, triacylglyceride (TG) accumulation was measured by Oil red O staining and mRNA level of markers related with lipid metabolism was determined by qRT-PCR. ResultsKaryotyping revealed two X chromosomes were present in 3T3-L1 cells. After differentiation with FUL and AP811, the NPR3 expression significantly decreased compared with 3T3-L1 cells treated with AP811 alone, indicating that NPR3 might be obesity-induced female-specific gene. Treatment with FUL and AP811 increased TG accumulation, which was accounted for the increased expression of adipogenic markers (PPARγ, CEBPα) and reduced expression of markers involved in mitochondrial biogenesis (NRF1, DRP1). ConclusionsOur data show that the NPR3 gene influences the adipogenic differentiation in a sex-specific manner, suggesting sex- and gender-based strategies for the prevention and treatment of obesity need to be established. Funding SourcesThis work was supported by the Support Program for Women in Science, Engineering and Technology through the Center for Women In Science, Engineering and Technology (WISET) funded by the Ministry of Science and ICT (MSIT) and the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT).

LIFR-α-dependent adipocyte signaling in obesity limits adipose expansion contributing to fatty liver disease

SummaryThe role of chronic adipose inflammation in diet-induced obesity (DIO) and its sequelae including fatty liver disease remains unclear. Leukemia inhibitory factor (LIF) induces JAK-dependent adipocyte lipolysis and altered adipo/cytokine expression, suppressing in vivo adipose expansion in normal and obese mouse models. To characterize LIF receptor (LIFR-α)-dependent cytokine signaling in DIO, we created an adipocyte-specific LIFR knockout mouse model (Adipoq-Cre;LIFRfl/fl). Differentiated adipocytes derived from this model blocked LIF-induced triacylglycerol lipolysis. Adipoq-Cre;LIFRfl/fl mice on a high-fat diet (HFD) displayed reduced adipose STAT3 activation, 50% expansion in adipose, 20% body weight increase, and a 75% reduction in total hepatic triacylglycerides compared with controls. To demonstrate that LIFR-α signals adipocytes through STAT3, we also created an Adipoq-Cre;STAT3fl/fl model that showed similar findings when fed a HFD as Adipoq-Cre;LIFRfl/fl mice. These findings establish the importance of obesity-associated LIFR-α/JAK/STAT3 inflammatory signaling in adipocytes, blocking further adipose expansion in DIO contributing to ectopic liver triacylglyceride accumulation.

ЭНДОКРИННАЯ ФУНКЦИЯ ЖИРОВОЙ ТКАНИ (ОБЗОР ЛИТЕРАТУРЫ)

Adipose tissue serves not only as a place for the accumulation and storage of triacylglycerides as energy substrates, but also produces many hormone-like substances, mediators, cytokines, chemokines that act at the local and systemic level and aff ect metabolism, regulate tissue sensitivity to insulin, reproductive and the immune system. The review presents the current results of scientifi c research on the problem of the physiological role of biologically active substances produced by adipose tissue and their participation in the development of metabolic disorders.

1H-NMR based lipid profiling of Gossypium hirsutum seed oil at different developmental stages

1H-NMR spectroscopy is emerging as powerful robust analytical technique in analyzing bio constituents present in plants. It offers non-invasive method for identification and quantification of several Phyto-constitutes in a single step without much pre-processing of the samples. In the present study, 1H-NMR spectroscopy-based lipid profiling was performed on Gossypium hirsutum seeds, which were collected at different developmental stages. 1H-NMR study reveals the presence of sterols, butyl ester of fatty acids, free fatty acids (FFA), triacyl glycerides (TAG), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA) and saturated fatty acids (SFA) at different percentage at different developmental stages. The 1H-NMR result demonstrates the presence of high concentration of FFA in early developmental stage and increased concentration of TAG at maturation stage. The 1H-NMR results suggest that stage III of seed development can be identified as turning point, as at this stage sterols and butyl ester of fatty acids becomes insignificant followed by high accumulation of TAG.

PLHC-1 topminnow liver cells: An alternative model to investigate the toxicity of plastic additives in the aquatic environment

Plasticizers are widespread environmental contaminants that have been described as obesogens in terrestrial vertebrates. However, its effects on fish lipids homeostasis are almost unknown. This work explores the use of PLHC-1 cells as an alternative model to assess the disruption of hepatic lipids by plastic additives and to gather information on the mode of action of these chemicals in fish. PLHC-1 lipid extracts were analyzed by flow injection coupled to high resolution mass spectrometry (FIA-ESI(+/-)-Orbitrap-Exactive) after 24 h exposure of the cells to the selected plasticizers: dibutyl phthalate (DBP), di-(2-ethylhexyl) phthalate (DEHP), bisphenol A (BPA), bisphenol F (BPF), and chlorinated bisphenol A diglycidyl ether (BADGE·2HCl). The analysis of the culture medium and the intracellular concentration of the chemicals revealed the highest bioconcentration of BADGE·2HCl, DBP and DEHP, which was in agreement with the strongest alteration of the cells lipidome. BADGE·2HCl induced a significant depletion of triacylglycerides (TGs), while DEHP and DBP stimulated the accumulation of TGs. Exposure to BPF induced the generation of reactive oxygen species in PLHC-1 cells and a significant depletion of phosphatidylcholine (PC)- and phosphatidylethanolamine (PE)-plasmalogens, and TGs (cell depots of polyunsaturated fatty acids). Overall, this study evidences different modes of action of plastic additives in topminnow liver cells, describes differential lipidomic signatures, and highlights the higher lipotoxicity of BADGE·2HCl and BPF compared to BPA.

Kinetic modelling of the biochemical 9-octadecenedioic acid production and lipid accumulation using differently functionalised C18:1 substrates

The potential use of different hydrophobic substrates (oleic acid, oleyl alcohol, methyl oleate and rapeseed oil) for the production of high concentrations of 9-octadecenedioic acid by the genetically engineered C. tropicalis ATCC-20962 yeast was researched. For comparison purposes, data for growth, intracellular triacylglyceride (TAG) accumulation and dicarboxylic acid (DCA) production were obtained for mathematical description using both known and newly adapted models. Fermentations were carried out in an aerated, stirred 2L-fermenter in which temperature (30°C) and pH (8.2) were controlled automatically. Using oleic acid resulted in the highest DCA production, i.e. 31.3 g.L−1 in 144 h, as well as the highest intracellular TAG concentration (60.5 m%). Mass balance calculations proved that 35 % of the consumed oleic acid was used for TAG accumulation. The oleyl alcohol and rapeseed oil substrates showed high initial DCA production rates as well, however, after 80 h, DCA production stopped to reach a maximum. In contrast, with methyl oleate substrate, a very slow production was observed without approaching a maximum within the experimental time.