Fatty Acid Modification Research Articles

Tracking lipid synthesis using 2H2O and 2H-NMR spectroscopy in black soldier fly (Hermetia illucens) larvae fed with macroalgae.

Black soldier fly (Hermetia illucens) larvae are used to upcycle biowaste into insect biomass for animal feed. Previous research on black soldier fly has explored the assimilation of dietary fatty acids (FAs), but endogenous FA synthesis and modification remain comparatively unexplored. This study presents a 1H/2H-NMR methodology for measuring lipid synthesis in black soldier fly larvae using diluted deuterated water (2H2O) as a stable isotopic tracer delivered through the feeding media. This approach was validated by measuring 2H incorporation into the larvae's body water and consequent labelling of FA esterified into triacylglycerols. A 5% 2H enrichment in the body water, adequate to label the FA, is achieved after 24 h in a substrate with 10% 2H2O. A standard feeding trial using an invasive macroalgae was designed to test this method, revealing de novo lipogenesis was lower in larvae fed with macroalgae, probably related to the poor nutritional value of the diet.

Amphiphilic layered double hydroxides enhance plant-mediated delivery of dsRNAs to phloem‑feeding planthoppers

RNA interference (RNAi) is an emerging tool in crop protection by exogenous applications of double-stranded RNAs (dsRNAs) to silence the expression of essential pest genes. Nevertheless, topical delivery of dsRNAs to sap-sucking insects is a major challenge due to the insufficient infiltration and translocation to plant vascular. Foliar sprayed layered double hydroxide (LDH) showed insufficient translocation in plant vascular and the supplement of surfactants caused phytotoxicity to plant. Thus, in the present study, LDH was transformed from hydrophilic to amphiphilic by fatty acids modification to obtain a surfactant-like LDH (LDHS) with good leaf adhesion, translocation and excellent biocompatibility. LDHS was synthesized via a mild hydrothermal method using MgCl2, FeCl3 and palm oil as the precursors, resulting in LDH coated with long-chained carboxylates as hydrophobic tails. LDHS showed good binding affinity with dsRNA and high affinity to rice leaves. Once loaded with dsRNA, LDHS were shown to enhance the uptake of dsRNA to rice brown planthoppers (Nilaparvata lugens) through a direct spray. Moreover, in planta, dsRNA-LDHS exhibited translocation from rice leaves to vascular bundles and finally into the planthoppers, delivered 2.5-fold higher dsRNA and caused higher mortalities of planthoppers than hydrophilic LDH with adjuvants. Herein we generate and validate a platform that can deliver dsRNA through either direct sprays or sprayed living plant to brown planthoppers with high efficiency, low toxicity and adjuvant-free. Consequently, it is a green potential selection using amphiphilic LDHS agents instead of the conventional gene carriers to prepare biopesticide nanoparticles.

Disorders of fatty acid homeostasis.

Humans derive fatty acids (FA) from exogenous dietary sources and/or endogenous synthesis from acetyl-CoA, although some FA are solely derived from exogenous sources ("essential FA"). Once inside cells, FA may undergo a wide variety of different modifications, which include their activation to their corresponding CoA ester, the introduction of double bonds, the 2- and ω-hydroxylation and chain elongation, thereby generating a cellular FA pool which can be used for the synthesis of more complex lipids. The biological properties of complex lipids are very much determined by their molecular composition in terms of the FA incorporated into these lipid species. This immediately explains the existence of a range of genetic diseases in man, often with severe clinical consequences caused by variants in one of the many genes coding for enzymes responsible for these FA modifications. It is the purpose of this review to describe the current state of knowledge about FA homeostasis and the genetic diseases involved. This includes the disorders of FA activation, desaturation, 2- and ω-hydroxylation, and chain elongation, but also the disorders of FA breakdown, including disorders of peroxisomal and mitochondrial α- and β-oxidation.

Long-term ambient ozone, omega-3 fatty acid, genetic susceptibility, and risk of mental disorders among middle-aged and older adults in UK biobank

BackgroundEvidence linking ozone to depression and anxiety disorders remains sparse and results are heterogeneous. It remains unknown whether omega-3 fatty acid, or genetic susceptibility of mental disorders modify the impacts of ozone. The aim is to assess the associations of ambient ozone with depression and anxiety, and further explore the potential modification effects of omega-3 fatty acid and genetic susceptibility. MethodsIn total of 257,534 participants were enrolled from 2006 to 2010 and followed up to 2016. Depression and anxiety were assessed using mental health questionnaires, primary care records and hospital admission records. The annual average concentrations of ozone were calculated and linked to individuals by home address. Dietary intake and plasma concentration were selected to reflect levels of omega-3 fatty acid. Polygenetic risk scores were selected to reflect genetic susceptibility. We examined the associations of ozone and incident mental disorders, and potential modification of omega-3 fatty acid and genetic susceptibility. ResultsIncidences of depression (N = 6957) and anxiety (N = 6944) was associated with increase of ozone. Higher levels of omega-3 fatty acid might attenuate the ozone related depression risk. However, the modification effects of genetic susceptibility were not found. ConclusionsLong-term exposure to ambient ozone increase the risk of mental disorders among the middle aged and older adults, and omega-3 fatty acid could reduce the adverse effects of ozone on mental health. Higher intake of omega-3 fatty acid is a potential strategy to prevent the risks caused by ozone on public mental health.

Long-Term Strategies for Poorly Water-Soluble Peptides: Combining Fatty Acid Modification with PAS Fusion.

Bulevirtide, an entry inhibitor for the hepatitis B virus (HBV) and hepatitis D virus (HDV), is currently available on the European market. However, its clinical application is constrained by its short half-life and poor water solubility, rendering it unsuitable for fatty acid modification, aimed at achieving long-term effects. To address this limitation, we integrated a polypeptide chain consisting of Pro, Ala, and Ser at the C-terminus, which increased its hydrophilicity. To obtain the fusion sequence of A1 and A2, encompassing amino acids 1-47 of Bulevirtide and PAS, we used Escherichia coli fermentation expression. Subsequently, the N-terminal myristoyl groups of A1 and A2 were modified to yield Myr-A1 and Myr-A2, respectively. Five fatty acid moieties with the same hydrophilic spacers and different fatty acids were conjugated to analogs, generating 10 bioconjugations. The bioconjugates were then evaluated for their anti-HBV activity. Among them, HB-10 was selected for pharmacokinetic analysis and demonstrated a significantly prolonged half-life, with 5.88- and 13.18-fold increases in beagle dogs and rats, respectively. Additionally, higher drug doses resulted in substantially elevated liver concentrations. In conclusion, via fatty acid incorporation and PASylation, we successfully developed a novel Bulevirtide bioconjugate, HB-10, that exhibits an extended action duration. This compound holds substantial promise as a prospective long-acting entry inhibitor, warranting further investigation.

Enhancing Stability and Albumin Binding Efficiency of α-Conotoxin GI through Fatty Acid Modification.

α-Conotoxin GI is a competitive blocker of muscle-type acetylcholine receptors and holds the potential for being developed as a molecular probe or a lead compound for drug discovery. In this study, four fatty acid-modified α-conotoxin GI analogues of different lengths were synthesized by using a fatty acid modification strategy. Then, we performed a series of in vitro stability assays, albumin binding assays, and pharmacological activity assays to evaluate these modified mutants. The experimental results showed that the presence of fatty acids significantly enhanced the in vitro stability and albumin binding ability of α-conotoxin GI and that this effect was proportional to the length of the fatty acids used. Pharmacological activity tests showed that the modified mutants maintained a good acetylcholine receptor antagonistic activity. The present study shows that fatty acid modification can be an effective strategy to significantly improve conotoxin stability and albumin binding efficiency while maintaining the original targeting ion channel activity.

Fatty acid modification of casein bioactive peptides nano-assemblies, synthesis, characterization and anticarcinogenic effect

In this study, the nano-assemblies of bovine casein hydrolyzed peptides (HP) modified by fatty acids with various alkyl chain lengths (C8, C10, C12 and C14) were synthesized. The physicochemical properties of HP-C8-HP-C14 nano-assemblies were characterized using spectra, laser particle size analyzer, contact angle meter, scanning electron microscope (SEM) and cryo-transmission electron microscope (Cryo-TEM). HP-C8 and HP-C10 self-assembled into a hollow cube cage with an average size of ~500 nm, and the assembly of HP-C12 showed a flower-shaped morphology with more dispersed behavior, and droplet size was observed as ~20 nm. The in vitro cytotoxicity against human breast cancer cells MCF-7 was tested using CCK-8 assay and flow cytometry analysis. HP-C12 showed the highest cytotoxicity for MCF-7 cells with an inhibition rate of 66.03 % ± 0.35 % with an IC50 value of 7.4 μM among HP-Cn. HP-C8, HP-C10 and HP-C12 significantly affected on the migration, invasion and apoptosis of MCF-7 cells. The apoptosis mechanism may depend on the upregulation of anti-apoptotic protein Bcl-2 as well as pro-apoptotic proteins Bax and caspase-8. The dead MCF-7 cells were analyzed with UHPLC-MS/MS using untargeted metabolomics, revealing key metabolic pathways.

Identification and optimization of peptide inhibitors to block VISTA/PSGL-1 interaction for cancer immunotherapy.

Developing new therapeutic agents for cancer immunotherapy is highly demanding due to the low response ratio of PD-1/PD-L1 blockade in cancer patients. Here, we discovered that the novel immune checkpoint VISTA is highly expressed on a variety of tumor-infiltrating immune cells, especially myeloid derived suppressor cells (MDSCs) and CD8+ T cells. Then, peptide C1 with binding affinity to VISTA was developed by phage displayed bio-panning technique, and its mutant peptide VS3 was obtained by molecular docking based mutation. Peptide VS3 could bind VISTA with high affinity and block its interaction with ligand PSGL-1 under acidic condition, and elicit anti-tumor activity invivo. The peptide DVS3-Pal was further designed by d-amino acid substitution and fatty acid modification, which exhibited strong proteolytic stability and significant anti-tumor activity through enhancing CD8+ T cell function and decreasing MDSCs infiltration. This is the first study to develop peptides to block VISTA/PSGL-1 interaction, which could act as promising candidates for cancer immunotherapy.

Influence of Fatty Acid Modification on the Anticancer Activity of the Antimicrobial Peptide Figainin 1.

Antimicrobial peptides derived from the skin secretions of amphibians have made important progress in tumor therapy due to their unique mechanism of destroying cell membranes. Figainin 1 (F1) is an 18-amino acid antimicrobial peptide from the skin secretions of Boana raniceps frogs. In a previous study, F1 was shown to inhibit cancer cell proliferation. F1 is composed entirely of natural amino acids; therefore, it is easily degraded by a variety of proteases, resulting in poor stability and a short half-life. In the present study, we used a fatty acid modification strategy to improve the stability of Figainin 1. Among the 8 peptides synthesized, A-10 showed the strongest antiproliferative activity against K562 cells and the other four tumor cell lines, and its stability against serum and proteinase K was improved compared with F1. We found that A-10 works through two mechanisms, cell membrane destruction and apoptosis, and can arrest the cell cycle in the G0/G1 phase. Moreover, A-10 exhibited self-assembly behavior. Overall, it is necessary to select a fatty acid with a suitable length for modification to improve the stability and antiproliferative activity of antimicrobial peptides. This study provides a good reference for the development of antimicrobial peptides as effective anticancer compounds.

Impaired Reverse Cholesterol Transport is Associated with Changes in Fatty Acid Profile in Children and Adolescents with Abdominal Obesity

BackgroundAbdominal obesity is an important cardiovascular disease risk factor. Plasma fatty acids display a complex network of both pro and antiatherogenic effects. High density lipoproteins (HDL) carry out the antiatherogenic pathway called reverse cholesterol transport (RCT), which involves cellular cholesterol efflux (CCE), and lecithin:cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP) activities. ObjectivesOur aim was to characterize RCT and its relation to fatty acids present in plasma in pediatric abdominal obesity. MethodsSeventeen children and adolescents with abdominal obesity and 17 healthy controls were studied. Anthropometric parameters were registered. Glucose, insulin, lipid levels, CCE employing THP-1 cells, LCAT and CETP activities, plus fatty acids in apo B-depleted plasma were measured. ResultsThe obese group showed a more atherogenic lipid profile, plus lower CCE (Mean±Standard Deviation) (6 ± 2 vs. 7 ± 2%; P < 0.05) and LCAT activity (11 ± 3 vs. 15 ±5 umol/dL.h; P < 0.05). With respect to fatty acids, the obese group showed higher myristic (1.1 ± 0.3 vs. 0.7 ± 0.3; P < 0.01) and palmitic acids (21.5 ± 2.8 vs. 19.6 ± 1.9; P < 0.05) in addition to lower linoleic acid (26.4 ± 3.3 vs. 29.9 ± 2.6; P < 0.01). Arachidonic acid correlated with CCE (r = 0.37; P < 0.05), myristic acid with LCAT (r = -0.37; P < 0.05), palmitioleic acid with CCE (r = -0.35; P < 0.05), linoleic acid with CCE (r = 0.37; P < 0.05), lauric acid with LCAT (r = 0.49; P < 0.05), myristic acid with LCAT (r = -0.37; P < 0.05) ecoisatrienoic acid with CCE (r = 0.40; P < 0.05) and lignoseric acid with LCAT (r = -0.5; P < 0.01). ConclusionsChildren and adolescents with abdominal obesity presented impaired RCT, which was associated with modifications in proinflammatory fatty acids, such as palmitoleic and myristic, thus contributing to increased cardiovascular disease risk.

Genetic Characterization of the Acidic and Neutral Glycosphingolipid Biosynthetic Pathways in Neurospora crassa.

Fungal glycosphingolipids (GSLs) are important membrane components which play a key role in vesicle trafficking. To assess the importance of GSLs in the fungal life cycle, we performed a mutant phenotypic study of the acidic and neutral GSL biosynthetic pathways in Neurospora crassa. GSL biosynthesis begins with two reactions leading up to the formation of dihydrosphingosine. The first of these reactions is catalyzed by serine palmitoyltransferase and generates 3-keto dihydrosphinganine. In N. crassa, this reaction is catalyzed by GSL-1 and GSL-2 and is required for viability. The second reaction is carried out by GSL-3, a 3-keto dihydrosphinoganine reductase to generate dihydrosphingosine, which is used for the synthesis of neutral and acidic GSLs. We found that deletion mutations in the acidic GSL pathway leading up to the formation of mannosylinositol-phosphoceramide are lethal, indicating that acidic GSLs are essential for viability in N. crassa. Once mannosylinositol-phosphoceramide is made, it is further modified by GSL-5, an inositol-phosphoceramide-B C26 hydroxylase, which adds a hydroxyl group to the amide-linked fatty acid. GSL-5 is not required for viability but gives a clear mutant phenotype affecting all stages of the life cycle. Our results show that the synthesis of mannosylinositol-phosphoceramide is required for viability and that the modification of the amide-linked fatty acid is important for acidic GSL functionality. We also examined the neutral GSL biosynthetic pathway and identified the presence of glucosylceramide. The deletion of neutral GSL biosynthetic genes affected hyphal morphology, vegetative growth rate, conidiation, and female development. Our results indicate that the synthesis of neutral GSLs is essential for normal growth and development of N. crassa.

Disturbance alters phytoplankton functional traits and consequently drives changes in zooplankton life-history traits and lipid composition

In the light of the current biodiversity crisis that affects in particular freshwater ecosystems, it is crucial to understand the effects of functional diversity loss on phytoplankton-zooplankton interactions in freshwater food webs. Here, we simulated the loss of phytoplankton trait diversity by applying different intensities of mechanical disturbance to a natural phytoplankton community in a laboratory experiment. Different disturbance regimes clearly affected the trait distribution and functional diversity of these phytoplankton communities. In the experiment’s second phase, these altered communities were provided as a food source to the zooplankton grazers Daphnia longispina and Eudiaptomus graciloides and their life-history traits and lipid compositions were investigated. Both zooplankton fitness and reproductive success were affected differently, depending on the grazers’ feeding modes. Phytoplankton fatty acid composition was generally reflected in the consumers’ tissue. Nevertheless, some selective PUFAs accumulation occurred and mismatches in some fatty acids suggested a possible enzymatic modification of dietary fatty acids adopted to face biochemical deficiencies of the diets. Overall, this study highlights how a loss of specific traits in resource communities could impact consumer communities, and shows how these altered community traits may affect food web dynamics.

Targeting the Inflammatory Hallmarks of Obesity-Associated Osteoarthritis: Towards Nutraceutical-Oriented Preventive and Complementary Therapeutic Strategies Based on n-3 Polyunsaturated Fatty Acids.

Obesity (Ob), which has dramatically increased in the last decade, is one of the main risk factors that contribute to the incidence and progression of osteoarthritis (OA). Targeting the characteristics of obesity-associated osteoarthritis (ObOA) may offer new chances for precision medicine strategies in this patient cohort. First, this review outlines how the medical perspective of ObOA has shifted from a focus on biomechanics to the significant contribution of inflammation, mainly mediated by changes in the adipose tissue metabolism through the release of adipokines and the modification of fatty acid (FA) compositions in joint tissues. Preclinical and clinical studies on n-3 polyunsaturated FAs (PUFAs) are critically reviewed to outline the strengths and weaknesses of n-3 PUFAs' role in alleviating inflammatory, catabolic and painful processes. Emphasis is placed on potential preventive and therapeutic nutritional strategies based on n-3 PUFAs, with a focus on ObOA patients who could specifically benefit from reformulating the dietary composition of FAs towards a protective phenotype. Finally, tissue engineering approaches that involve the delivery of n-3 PUFAs directly into the joint are explored to address the perspectives and current limitations, such as safety and stability issues, for implementing preventive and therapeutic strategies based on dietary compounds in ObOA patients.

Pharmacokinetics of Biopharmaceuticals: Their Critical Role in Molecular Design.

Biopharmaceuticals have developed rapidly in recent years due to the remarkable progress in gene recombination and cell culture technologies. Since the basic structure of biopharmaceuticals can be designed and modified, it is possible to control the duration of action and target specific tissues and cells by kinetic modification. Amino acid sequence modifications, albumin fusion proteins, polyethylene glycol (PEG) modifications, and fatty acid modifications have been utilized to modify the duration of action control and targeting. This review first describes the position of biopharmaceuticals, and then the kinetics (absorption, distribution, metabolism, elimination, and pharmacokinetics) of classical biopharmaceuticals and methods of drug quantification. The kinetic innovations of biopharmaceuticals are outlined, including insulin analog, antibody-related drugs (monoclonal antibodies, Fab analogs, Fc analogs, Fab-PEG conjugated proteins, antibody-drug conjugates, etc.), blood coagulation factors, interferons, and other related drugs. We hope that this review will be of use to many researchers interested in pharmaceuticals derived from biological components, and that it aids in their knowledge of the latest developments in this field.

Effects of Salinity on Lipid Composition in Juvenile Pinc Salmon Oncorhynchus gorbuscha (Salmonidae)

Lipid and fatty acid modifications induced by the effects of various salinity patterns on the juvenile pink salmon Oncorhynchus gorbuscha (the Olkhovka River and the White Sea) within the experiment have been revealed. Concentrations of steroids, saturated fatty acids, and signaling molecules such as phospholipids (phosphatidylserine and phosphatidylinositol) and arachidonic acid under the hyperosmotic stress-related effects (keeping the fish for 1 h in the seawater after the time of transfer from the freswater) tend to increase. Decreases in phosphatidylcholine and n-6 saturated, monounsaturated, and polyunsaturated fatty acids are recorded in the juvenile pink salmon fish kept for 24 h in the seawater after the time of transfer them from the freswater, while the levels of phosphatidylethanolamine and n-3 polyunsaturated fatty acids (especially eicosapentaenoic and docosahexaenoic acids), on the contrary, tend to rise significantly. Lipid composition modifications in the juvenile pink salmon fish kept under the hypoosmotic stress conditions (24 h in freshwater after 24 h in seawater) induce stabilization of functioning the cell membrane structure, since the levels of bioeffectors including phosphatidylserine, phosphatidylinositol, and arachidonic, eicosapentaenoic, and docosahexaenoic acids tend to decrease. A reduced amount of lipids (triacylglycerols) stored as an energy reserve is shown for all the experimental fish groups. The outcomes indicate the high levels of adaptive potential of the juvenile pink salmon fish kept under the effects of abrupt salinity change in the water environments and their readiness for downstream migration not long before leaving the nests.

Modification of serum fatty acids in preterm infants by parenteral lipids and enteral docosahexaenoic acid/arachidonic acid: A secondary analysis of the Mega Donna Mega trial

Preterm infants risk deficits of long-chain polyunsaturated fatty acids (LCPUFAs) that may contribute to morbidities and hamper neurodevelopment. We aimed to determine longitudinal serum fatty acid profiles in preterm infants and how the profiles are affected by enteral and parenteral lipid sources. Cohort study analyzing fatty acid data from the Mega Donna Mega study, a randomized control trial with infants born <28 weeks of gestation (n=204) receiving standard nutrition or daily enteral lipid supplementation with arachidonic acid (AA):docosahexaenoic acid (DHA) (100:50mg/kg/day). Infants received an intravenous lipid emulsion containing olive oil:soybean oil (4:1). Infants were followed from birth to postmenstrual age 40 weeks. Levels of 31 different fatty acids from serum phospholipids were determined by GC-MS and reported in relative (mol%) and absolute concentration (μmol l-1) units. Higher parenteral lipid administration resulted in lower serum proportion of AA and DHA relative to other fatty acids during the first 13 weeks of life (p<0.001 for the 25th vs the 75th percentile). The enteral AA:DHA supplement increased the target fatty acids with little impact on other fatty acids. The absolute concentration of total phospholipid fatty acids changed rapidly in the first weeks of life, peaking at day 3, median (Q1-Q3) 4452 (3645-5466) μmol l-1, and was positively correlated to the intake of parenteral lipids. Overall, infants displayed common fatty acid trajectories over the study period. However, remarkable differences in fatty acid patterns were observed depending on whether levels were expressed in relative or absolute units. For example, the relative levels of many LCPUFAs, including DHA and AA, declined rapidly after birth while their absolute concentrations increased in the first week of life. For DHA, absolute levels were significantly higher compared to cord blood from day 1 until postnatal week 16 (p<0.001). For AA, absolute postnatal levels were lower compared to cord blood from week 4 throughout the study period (p<0.05). Our data show that parenteral lipids aggravate the postnatal loss of LCPUFAs seen in preterm infants and that serum AA available for accretion is below that in utero. Further research is needed to establish optimal postnatal fatty acid supplementation and profiles in extremely preterm infants to promote development and long-term health. ClinicalTrials.gov, identifier: NCT03201588.

Fatty acid modification of antimicrobial peptide CGA-N9 and the combats against Candida albicans infection

High-efficiency and low-toxic antimicrobial peptides (AMPs) are supposed to be the future candidates to solve the increasingly prominent problems of Candida albicans infection and drug resistance. Generally, introduction of hydrophobic moieties on AMPs resulted in analogues with remarkably increased activity against pathogens. CGA-N9, an antifungal peptide found in our lab, is a Candida-selective antimicrobial peptide capable of preferentially killing Candida spp. relative to benign microorganisms with low toxicities. We speculate that fatty acid modification could improve the anti-Candida activity of CGA-N9. In the present investigation, a set of CGA-N9 analogues with fatty acid conjugations at N-terminus were obtained. The biological activities of CGA-N9 analogues were determined. The results showed that the n-octanoic acid conjugation of CGA-N9 (CGA-N9-C8) was the optimal CGA-N9 analogue with the highest anti-Candida activity and biosafety; exhibited the strongest biofilm inhibition activity and biofilm eradication ability; and the highest stability against protease hydrolysis in serum. Furthermore, CGA-N9-C8 is less prone to develop resistance for C. albicans in reference with fluconazole; CGA-N9-C8 also exhibited Candidacidal activity to the planktonic cells and the persister cells of C. albicans; reduced C. albicans susceptibility in a systemic candidiasis mouse model. In conclusion, fatty acid modification is an effective method to enhance the antimicrobial activity of CGA-N9, and CGA-N9-C8 is a promising candidate to defend C. albicans infection and resolve C. albicans drug resistance.

Protein interactomes for plant lipid biosynthesis and their biotechnological applications.

Plant lipids have essential biological roles in plant development and stress responses through their functions in cell membrane formation, energy storage and signalling. Vegetable oil, which is composed mainly of the storage lipid triacylglycerol, also has important applications in food, biofuel and oleochemical industries. Lipid biosynthesis occurs in multiple subcellular compartments and involves the coordinated action of various pathways. Although biochemical and molecular biology research over the last few decades has identified many proteins associated with lipid metabolism, our current understanding of the dynamic protein interactomes involved in lipid biosynthesis, modification and channelling is limited. This review examines advances in the identification and characterization of protein interactomes involved in plant lipid biosynthesis, with a focus on protein complexes consisting of different subunits for sequential reactions such as those in fatty acid biosynthesis and modification, as well as transient or dynamic interactomes formed from enzymes in cooperative pathways such as assemblies of membrane-bound enzymes for triacylglycerol biosynthesis. We also showcase a selection of representative protein interactome structures predicted using AlphaFold2, and discuss current and prospective strategies involving the use of interactome knowledge in plant lipid biotechnology. Finally, unresolved questions in this research area and possible approaches to address them are also discussed.

Equine osteoarthritis modifies fatty acid signatures in synovial fluid and its extracellular vesicles

BackgroundIndividual fatty acids (FAs) and their derivatives (lipid mediators) with pro-inflammatory or dual anti-inflammatory and pro-resolving properties have potential to influence the health of joint tissues. Osteoarthritis (OA) is an age-associated chronic joint disease that can be featured with altered FA composition in the synovial fluid (SF) of human patients. The counts and cargo of extracellular vesicles (EVs), membrane-bound particles released by synovial joint cells and transporting bioactive lipids, can also be modified by OA. The detailed FA signatures of SF and its EVs have remained unexplored in the horse — a well-recognized veterinary model for OA research.MethodsThe aim of the present study was to compare the FA profiles in equine SF and its ultracentrifuged EV fraction between control, contralateral, and OA metacarpophalangeal joints (n = 8/group). The FA profiles of total lipids were determined by gas chromatography and the data compared with univariate and multivariate analyses.ResultsThe data revealed distinct FA profiles in SF and its EV-enriched pellet that were modified by naturally occurring equine OA. Regarding SFs, linoleic acid (generalized linear model, p = 0.0006), myristic acid (p = 0.003), palmitoleic acid (p < 0.0005), and n-3/n-6 polyunsaturated FA ratio (p < 0.0005) were among the important variables that separated OA from control samples. In EV-enriched pellets, saturated FAs palmitic acid (p = 0.020), stearic acid (p = 0.002), and behenic acid (p = 0.003) indicated OA. The observed FA modifications are potentially detrimental and could contribute to inflammatory processes and cartilage degradation in OA.ConclusionsEquine OA joints can be distinguished from normal joints based on their FA signatures in SF and its EV-enriched pellet. Clarifying the roles of SF and EV FA compositions in the pathogenesis of OA and their potential as joint disease biomarkers and therapeutic targets warrants future studies.

Red blood cells from patients with sitosterolemia exhibit impaired membrane lipid composition and distribution and decreased deformability

Sitosterolemia is a metabolic disorder leading to excessive accumulation of phytosterols. Hemolytic stomatocytosis and macrothrombocytopenia are part of the clinical picture. However, the impact of phytosterols on red blood cell (RBC) deformability, membrane lipid composition and distribution and the efficiency of the reference treatment, Ezetimibe, are largely unknown. This study addresses these issues using RBCs from three patients with sitosterolemia and healthy RBCs exposed to β-sitosterol. Patients presented an increased proportion of stomatocytes, decreased RBC deformability and increased RBC hydration and osmotic fragility compared to healthy donors. At the membrane level, patient RBCs showed (i) very high content in β-sitosterols, (ii) increased proportions of saturated fatty acids and polyunsaturated fatty acid species with long and unsaturated carbon chains, and (iii) decreased content in phosphatidylethanolamine species. These lipid changes were accompanied by an almost complete abrogation of cholesterol-enriched domains, which could result from: (i) the reduced phosphatidylethanolamine content which positively correlated with domain abundance; and (ii) the fatty acid modifications and increased phytosterol content, both compatible with higher membrane stiffness. The role of β-sitosterol was supported by comparable changes in RBC morphology and cholesterol-enriched domains upon β-sitosterol integration at the healthy RBC membrane. Finally, Ezetimibe treatment combined with a sterol restricted diet lowered phytosterols and improved anemia and RBC deformability and hydration. However, this treatment had no or limited effect on RBC morphology and cholesterol-enriched domain abundance. This study reveals for the first time that phytosterols affect RBC membrane lipid composition and distribution but also RBC morphology, hydration, deformability and fragility.