Mitigating phospholipid peroxidation of macrophages in stress-induced tumor microenvironment by natural ALOX15/PEBP1 complex inhibitors.

BACKGROUND: The intricate interactions between chronic psychological stress and susceptibility to breast cancer have been recognized, yet the underlying mechanisms remain unexplored. Danzhi Xiaoyao Powder (DZXY), a traditional Chinese medicine (TCM) formula, has found clinical utility in the treatment of breast cancer. Macrophages, as the predominant immune cell population within the tumor microenvironment (TME), play a pivotal role in orchestrating tumor immunosurveillance. Emerging evidence suggests that lipid oxidation accumulation in TME macrophages, plays a critical role in breast cancer development and progression. However, a comprehensive understanding of the pharmacological mechanisms and active components of DZXY related to its clinical application in the treatment of stress-aggravated breast cancer remains elusive. PURPOSE: This study sought to explore the plausible regulatory mechanisms and identify the key active components of DZXY contributing to its therapeutic efficacy in the context of breast cancer. METHODS: Initially, we conducted an investigation into the relationship between the phagocytic capacity of macrophages damaged by psychological stress and phospholipid peroxidation using flow cytometry and LC-MS/MS-based phospholipomics. Subsequently, we evaluated the therapeutic efficacy of DZXY based on the results of the tumor size, tumor weight, the phospholipid peroxidation pathway and phagocytosis of macrophage. Additionally, the target-mediated characterization strategy based on binding of arachidonate 15-lipoxygenase (ALOX15) to phosphatidylethanolamine-binding protein-1 (PEBP1), including molecular docking analysis, microscale thermophoresis (MST) assay, co-immunoprecipitation analysis and activity verification, has been further implemented to reveal the key bio-active components in DZXY. Finally, we evaluated the therapeutic efficacy of isochlorogenic acid C (ICAC) based on the results of tumor size, tumor weight, the phospholipid peroxidation pathway, and macrophage phagocytosis in vivo. RESULTS: The present study demonstrated that phospholipid peroxides, as determined by LC-MS/MS-based phospholipidomics, triggered in macrophages, which in turn compromised their capacity to eliminate tumor cells through phagocytosis. Furthermore, we elucidate the mechanism behind stress-induced PEBP1 to form a complex with ALOX15, thereby mediating membrane phospholipid peroxidation in macrophages. DZXY, demonstrates potent anti-breast cancer therapeutic effects by disrupting the ALOX15/PEBP1 interaction and inhibiting phospholipid peroxidation, ultimately enhancing macrophages' phagocytic capability towards tumor cells. Notably, ICAC emerged as a promising active component in DZXY, which can inhibit the ALOX15/PEBP1 interaction, thereby mitigating phospholipid peroxidation in macrophages. CONCLUSION: Collectively, our findings elucidate stress increases the susceptibility of breast cancer by driving lipid peroxidation of macrophages and suggest the ALOX15/PEBP1 complex as a promising intervention target for DZXY.

The effect of naringenin-phospholipid complex on thermal oxidative stability of soybean oil under heating condition.

Naringenin (NGE), a typical flavanone abundant in citrus fruits, exhibits remarkable antioxidant activities. However, its low solubility in oil restricts its widespread use in inhibiting lipid oxidation. In this study, we present a novel and effective approach to address this limitation by developing a naringenin-phospholipid complex (NGE-PC COM). Comprehensive analytical techniques including Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) were employed to confirm the formation of the NGE-PC COM and elucidate the interaction mechanism between NGE and phospholipids molecules. Notably, the oil-solubility of NGE was significantly enhanced by approximately 2700-fold when formulated as a phospholipid complex in soybean oil. The improved oil-solubility of NGE-PC COM enabled effective inhibition of oil thermal oxidation under high temperature conditions. Generally, this investigation proposed a novel and promising strategy for employing flavanones with strong antioxidant activities to enhance the thermal oxidative stability of edible oil during heating processes.

Microbial strategies for phosphorus acquisition in rice paddies under contrasting water regimes: Multiple source tracing by 32P and 33P.

Microbial acquisition and utilization of organic and mineral phosphorus (P) sources in paddy soils are strongly dependent on redox environment and remain the key to understand P turnover and allocation for cell compound synthesis. Using double 32/33P labeling, we traced the P from three sources in a P-limited paddy soil: ferric iron-bound phosphate (Fe-P), wheat straw P (Straw-P), and soil P (Soil-P) in microbial biomass P (MBP) and phospholipids (Phospholipid-P) of individual microbial groups depending on water regimes: (i) continuous flooding or (ii) alternate wetting and drying. 32/33P labeling combined with phospholipid fatty acid analysis allowed to trace P utilization by functional microbial groups. Microbial P nutrition was mainly covered by Soil-P, whereas microorganisms preferred to take up P from mineralized Straw-P than from Fe-P dissolution. The main Straw-P mobilizing agents were Actinobacteria under alternating wetting and drying and other Gram-positive bacteria under continuous flooding. Actinobacteria and arbuscular mycorrhiza increased P incorporation into cell membranes by 1.4-5.8 times under alternate wetting and drying compared to continuous flooding. The Fe-P contribution to MBP was 4-5 times larger in bulk than in rooted soil because (i) rice roots outcompeted microorganisms for P uptake from Fe-P and (ii) rhizodeposits stimulated microbial activity, e.g. phosphomonoesterase production and Straw-P mineralization. Higher phosphomonoesterase activities during slow soil drying compensated for the decreased reductive dissolution of Fe-P. Concluding, microbial P acquisition strategies depend on (i) Soil-P, especially organic P, availability, (ii) the activity of phosphomonoesterases produced by microorganisms and roots, and (iii) P sources - all of which depend on the redox conditions. Maximizing legacy P utilization in the soil as a function of the water regime is one potential way to reduce competition between roots and microbes for P in rice cultivation.

Upregulated selenoprotein I during lipopolysaccharide-induced B cell activation promotes lipidomic changes and is required for effective differentiation into IgM-secreting plasma B cells.

The mechanisms driving metabolic reprogramming during B cell activation are unclear, particularly roles for enzymatic pathways involved in lipid remodeling. We found that murine B cell activation with lipopolysaccharide (LPS) led to a 1.6-fold increase in total lipids that included higher levels of phosphatidylethanolamine (PE) and plasmenyl PE. Selenoprotein I (SELENOI) is an ethanolamine phospholipid transferase involved in the synthesis of both PE and plasmenyl PE, and SELENOI expression was also upregulated during activation. Selenoi knockout (KO) B cells exhibited decreased levels of plasmenyl PE, which plays an important antioxidant role. Lipid peroxidation was measured and found to increase ∼2-fold in KO vs. wild-type (WT) B cells. Cell death was not impacted by KO in LPS-treated B cells and proliferation was only slightly reduced, but differentiation into CD138 + Blimp-1+ plasma B cells was decreased ∼2-fold. This led to examination of B cell receptors important for differentiation that recognize the ligand B cell activating factor, and levels of TACI (transmembrane activator, calcium-modulator, and cytophilin ligand interactor) (CD267) were significantly decreased on KO B cells compared with WT control cells. Vaccination with ovalbumin/adjuvant led to decreased ovalbumin-specific immunoglobulin M (IgM) levels in sera of KO mice compared with WT mice. Real-time polymerase chain reaction analyses revealed a decreased switch from surface to secreted IgM in spleens of KO mice induced by vaccination or LP-BM5 retrovirus infection. Overall, these findings detail the lipidomic response of B cells to LPS activation and reveal the importance of upregulated SELENOI for promoting differentiation into IgM-secreting plasma B cells.

A cholesterol switch controls phospholipid scrambling by G protein-coupled receptors.

Class A G protein-coupled receptors (GPCRs), a superfamily of cell membrane signaling receptors, moonlight as constitutively active phospholipid scramblases. The plasma membrane of metazoan cells is replete with GPCRs yet has a strong resting trans-bilayer phospholipid asymmetry, with the signaling lipid phosphatidylserine confined to the cytoplasmic leaflet. To account for the persistence of this lipid asymmetry in the presence of GPCR scramblases, we hypothesized that GPCR-mediated lipid scrambling is regulated by cholesterol, a major constituent of the plasma membrane. We now present a technique whereby synthetic vesicles reconstituted with GPCRs can be supplemented with cholesterol to a level similar to that of the plasma membrane and show that the scramblase activity of two prototypical GPCRs, opsin and the ß1-adrenergic receptor, is impaired upon cholesterol loading. Our data suggest that cholesterol acts as a switch, inhibiting scrambling above a receptor-specific threshold concentration to disable GPCR scramblases at the plasma membrane.

Thyme Oil-Containing Fluconazole-Loaded Transferosomal Bigel for Transdermal Delivery.

The objective of the present research was to develop fluconazole-loaded transferosomal bigels for transdermal delivery by employing statistical optimization (23 factorial design-based). Thin-film hydration was employed to prepare fluconazole-loaded transferomal suspensions, which were then incorporated into bigel system. A 23 factorial design was employed where ratios of lipids to edge activators, lipids (soya lecithin to cholesterol), and edge activators (sodium deoxycholate to Tween 80) were factors. Ex vivo permeation flux (Jss) of transferosomal bigels across porcine skin was analyzed as response. The optimal setting for optimized formulation (FO) was A= 4.96, B= 3.82, and C= 2.16. The optimized transferosomes showed 52.38 ± 1.76% DEE, 76.37 nm vesicle size, 0.233 PDI, - 20.3 mV zeta potential, and desirable deformability. TEM of optimized transferosomes exhibited a multilamelar structure. FO bigel's FE-SEM revealed a globule-shaped vesicular structure. Further, the optimized transferosomal suspension was incorporated into thyme oil (0.1% w/w)-containing bigel (TO-FO). Ex vivo transdermal fluconazole permeation from different transferosomal bigels was sustained over 24 h. The highest permeation flux (4.101 µg/cm2/h) was estimated for TO-FO bigel. TO-FO bigel presented 1.67-fold more increments of antifungal activity against Candida albicans than FO bigel. The prepared thyme oil (0.1% w/w)-containing transfersomal bigel formulations can be used as topical delivery system to treat candida related fungal infections.

Thermodynamic and structural properties of lipid-photosensitizer conjugates mixed with phospholipids: Impact on the formation and stability of nano-assemblies.

The photosensitizer Phenalenone (PN) was grafted with one or two lipid (C18) chains to form pure nano-assemblies or mixed lipid vesicles suitable for photodynamic therapy. Mixtures of PN-C18 conjugates with stearoyl-oleoyl phosphatidylcholine (SOPC) form vesicles that disintegrate into bilayer sheets as the concentration of PN-C18 conjugates increases. We hypothesized that PN-C18 conjugates control the thermodynamic and structural properties of the mixtures and induce the disintegration of vesicles due to PN π-π-interactions. Monolayers were analyzed by surface pressure and grazing incidence X-ray diffraction (GIXD) measurements, and vesicles by differential scanning calorimetry and cryo-TEM. The results showed that PN-triazole-C18 (1A) and PN-NH-C18 (1B) segregate from the phospholipid domains. PN-(C18)2 (conjugate 2) develops favorable interactions with SOPC and distearoyl-phosphatidylcholine (DSPC). GIXD demonstrates the contribution of SOPC to the structuring of conjugate 2 and the role of the major component in controlling the structural properties of DSPC-conjugate 2 mixtures. Above 10 mol% conjugate 2 in SOPC vesicles, the coexistence of domains with different molecule packing leads to conjugate segregation, vesicle deformation, and the formation of small bilayer discs stabilized by the inter-bilayer π-π stacking of PN molecules.

Efficient modulation of cellular phosphorus components in response to phosphorus deficiency in the dinoflagellate Karenia mikimotoi.

IMPORTANCE: Dinoflagellates are the most common phytoplankton group and account for more than 75% of harmful algal blooms in coastal waters. In recent decades, dinoflagellates seem to prevail in phosphate-depleted waters. However, the underlying acclimation mechanisms and competitive strategies of dinoflagellates in response to phosphorus deficiency are poorly understood, especially in terms of intracellular phosphorus modulation and recycling. Here, we focused on the response of intracellular phosphorus metabolism to phosphorus deficiency in the model dinoflagellate Karenia mikimotoi. Our work reveals the strong capability of K. mikimotoi to efficiently regulate intracellular phosphorus resources, particularly through membrane phospholipid remodeling and miRNA regulation of energy metabolism. Our research improved the understanding of intracellular phosphorus metabolism in marine phytoplankton and underscored the advantageous strategies of dinoflagellates in the efficient modulation of internal phosphorus resources to maintain active physiological activity and growth under unsuitable phosphorus conditions, which help them outcompete other species in coastal phosphate-depleted environments.

Associations between Fatty Acid Intakes and Plasma Phospholipid Fatty Acid Concentrations in the European Prospective Investigation into Cancer and Nutrition.

BACKGROUND: The aim of this study is to determine the correlations between dietary fatty acid (FA) intakes and plasma phospholipid (PL) FA levels in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. METHODS: The dietary intake of 60 individual FAs was estimated using centre-specific validated dietary questionnaires. Plasma PL FA concentrations of these FAs were measured in non-fasting venous plasma samples in nested case-control studies within the EPIC cohort (n = 4923, using only non-cases). Spearman rank correlations were calculated to determine associations between FA intakes and plasma PL FA levels. RESULTS: Correlations between FA intakes and circulating levels were low to moderately high (-0.233 and 0.554). Moderate positive correlations were found for total long-chain n-3 poly-unsaturated FA (PUFA) (r = 0.354) with the highest (r = 0.406) for n-3 PUFA docosahexaenoic acid (DHA). Moderate positive correlations were also found for the non-endogenously synthesized trans-FA (r = 0.461 for total trans-FA C16-18; r = 0.479 for industrial trans-FA (elaidic acid)). CONCLUSIONS: Our findings indicate that dietary FA intakes might influence the plasma PL FA status to a certain extent for several specific FAs. The stronger positive correlations for health-enhancing long-chain PUFAs and the health-deteriorating trans-FA that are not endogenously produced are valuable for future cancer prevention public health interventions.

Berberine-phospholipid nanoaggregate-embedded thiolated chitosan hydrogel for aphthous stomatitis treatment.

Aim: This study aimed to develop nanoaggregates of berberine-phospholipid complex incorporated into thiolated chitosan (TCS) hydrogel for the treatment of aphthous stomatitis. Methods: The berberine-phospholipid complex was formulated through the solvent evaporation technique and assembled into nanoaggregates. TCS was synthesized through the attachment of thioglycolic acid to chitosan (CS). Nanoaggregates-TCS was prepared by the incorporation of nanoaggregates into TCS and underwent in vitro and in vivo tests. Results: Nanoaggregates-TCS exhibited prolonged release of berberine. The mucoadhesive strength of nanoaggregates-TCS increased 1.75-fold compared with CS hydrogel. In vivo studies revealed the superior therapeutic efficacy of nanoaggregates-TCS compared with that of other groups. Conclusion: Due to prolonged drug release, appropriate residence time and anti-inflammatory effects, nanoaggregates-TCS is an effective system for the treatment of aphthous stomatitis.

Biochar amendment reassembles microbial community in a long-term phosphorus fertilization paddy soil.

This study investigates the effect of biochar amendment on microbial community structure and soil nutrient status in paddy soil that has been fertilized for an extended period of time, shedding light on sustainable agricultural practices. A 90-day incubation period revealed that biochar amendment, as opposed to long-term fertilization, significantly influenced the physicochemical properties and microbial composition of the soil. The microcosm experiment conducted using six treatments analyzed soil samples from a long-term rice ecosystem. We employed microbial biomarkers (phospholipid fatty acids, PLFAs; isoprenoid and branched glycerol dialkyl glycerol tetraethers, iGDGTs and brGDGTs; DNA) to assess microbial biomass and community structure. Biochar addition led to a decrease in PLFA biomass (15-32%) and archaeal iGDGT abundance (14-43%), while enhancing bacterial brGDGT abundance by 15-77%. Intact biochar increased archaeal and bacterial diversity, though fungal diversity remained unchanged. However, acid-washed biochar did not result in a uniform microbial diversity response. The abundance of various microbial taxa was changed by biochar amendment, including Crenarchaeota, Proteobacteria, Nitrospira, Basidiomycota, Halobacterota, Chloroflexi, Planctomycetota, and Ascomycota. Soil NH4+-N was found as the primary environmental factor impacting the composition of archaea, bacteria, and fungus in this study. These findings imply that the addition of biochar has a quick influence on the structure and activity of microbial communities, with fungi possibly having a critical role in acid paddy soil. This study contributes valuable knowledge for developing sustainable agricultural practices that promote healthy soil ecosystems. KEY POINTS: • Biochar type and phosphorus fertilization demonstrated an interactive effect on the diversity of archaea, but no such effect was observed for bacteria and fungi. • Soil fungi contribute to approximately 20% of the total phospholipid fatty acid (PLFA) content. • Biochar, especially acid-washed rice straw biochar, increases glucose metabolism in bacteria and archaea and decreases saprophytic fungi.

A sustained-release phospholipid-based phase separation gel loaded with berberine for treating rheumatoid arthritis.

Berberine (BBR) has a long history of use in the treatment of Rheumatoid arthritis (RA) and is considered one of the most promising natural product for the treatment of RA. However, oral administration of berberine has low bioavailability and requires frequent administration, resulting in poor patient compliance. In this study, we developed a BBR-loaded phospholipid-based phase separation gel (BBR-PPSG) to achieve sustained drug release and long-term therapeutic effect. The stability of BBR-PPSG was verified and it was found that it can be stored for a long time. The pharmacokinetic study on rats and rabbits showed that BBR-PPSG not only achieved 1-month of sustained release, but also significantly increased the area under the curve (AUC) by nearly 9-fold and prolonged the half-life (t1/2) by 10-fold. By constructing rat and rabbit models of RA, we also proved that BBR-PPSG administration once a month effectively alleviated joint swelling, and significantly reduce TNF-α levels in AIA rats and OIA rabbits. Histopathological analysis of rabbit joint sections revealed that after intra-articular injection of BBR-PPSG, the synovial cell layer remained intact, while in the model group, the synovial cells were significantly reduced and exhibited necrosis. MicroCT data analysis showed that the values of Tb.N and Tb. Sp in the BBR-PPSG group were significantly better than those in the model group (p < 0.05). This study addressed the limitations of frequent administration of BBR by developing a phospholipid-based phase separation gel system for berberine delivery, achieving long-term sustained release. The BBR-PPSG demonstrated good biocompatibility, simple preparation and excellent stability, thus holding potential as a novel pharmaceutical formulation for RA treatment.

The Membrane Phospholipidomics Research of Oxidatively Damaged INS-1 Pancreatic Beta Cells Intervened by the Effective Constituents of Anemarrhenae Asphodeloides Rhizoma.

The rhizoma of Anemarrhenae asphodeloides has a long history of hypoglycemic use in Chinese traditional medicine. In this article, 400 µmol/L H2 O2 induced normal INS-1 pancreatic beta cells to establish experimental model of oxidative damage. Quercetin was used as a positive drug, and mangiferin and its ethanolic extract were selected as therapeutic agents in an oxidative damage model to evaluate the ameliorative effect of the active ingredients of Anemarrhenae asphodeloides rhizoma on oxidative damage in INS-1 pancreatic ß-cells. Building a qualitative analysis method of membrane phospholipids of INS-1 pancreatic beta cells and identified 82 phospholipids based on the UPLC/Q-TOF MS technology, which could provide a database for further statistics analysis. OPLS-DA was used to screen the phospholipid biomarkers from the raw data. Exploring the biological significances of these biomarkers, and discussing the toxic effect of the effective components of Anemarrhena asphodeloides rhizoma, on oxidatively damaged INS-1 pancreatic beta cell.

Effective magnetic hyperthermia induced by mitochondria-targeted nanoparticles modified with triphenylphosphonium-containing phospholipid polymers.

Magnetic hyperthermia (MHT) is a promising cancer treatment because tumor tissue can be specifically damaged by utilizing the heat generated by nano-heaters such as magnetite nanoparticles (MNPs) under an alternating magnetic field. MNPs are taken up by cancer cells, enabling intracellular MHT. Subcellular localization of MNPs can affect the efficiency of intracellular MHT. In this study, we attempted to improve the therapeutic efficacy of MHT by using mitochondria-targeting MNPs. Mitochondria-targeting MNPs were prepared by the modification of carboxyl phospholipid polymers containing triphenylphosphonium (TPP) moieties that accumulate in mitochondria. The mitochondrial localization of polymer-modified MNPs was supported by transmission electron microscopy observations of murine colon cancer CT26 cells treated with polymer-modified MNPs. In vitro and in vivo MHT using polymer-modified MNPs revealed that the therapeutic effects were enhanced by introducing TPP. Our results indicate the validity of mitochondria targeting in enhancing the therapeutic outcome of MHT. These findings will pave the way for developing a new strategy for the surface design of MNPs and therapeutic strategies for MHT.

Phospholipid:diacylglycerol acyltransferase1-overexpression stimulates lipid turnover, oil production and fitness in cold-grown plants.

BACKGROUND: Extensive population growth and climate change accelerate the search for alternative ways of plant-based biomass, biofuel and feed production. Here, we focus on hitherto unknow, new promising cold-stimulated function of phospholipid:diacylglycerol acyltransferase1 (PDAT1) - an enzyme catalyzing the last step of triacylglycerol (TAG) biosynthesis. RESULT: Overexpression of AtPDAT1 boosted seed yield by 160% in Arabidopsis plants exposed to long-term cold compared to standard conditions. Such seeds increased both their weight and acyl-lipids content. This work also elucidates PDAT1's role in leaves, which was previously unclear. Aerial parts of AtPDAT1-overexpressing plants were characterized by accelerated growth at early and vegetative stages of development and by biomass weighing three times more than control. Overexpression of PDAT1 increased the expression of SUGAR-DEPENDENT1 (SDP1) TAG lipase and enhanced lipid remodeling, driving lipid turnover and influencing biomass increment. This effect was especially pronounced in cold conditions, where the elevated synergistic expression of PDAT1 and SDP1 resulted in double biomass increase compared to standard conditions. Elevated phospholipid remodeling also enhanced autophagy flux in AtPDAT1-overexpresing lines subjected to cold, despite the overall diminished autophagy intensity in cold conditions. CONCLUSIONS: Our data suggest that PDAT1 promotes greater vitality in cold-exposed plants, stimulates their longevity and boosts oilseed oil production at low temperature.

Mfsd2a-mediated lysolipid transport is important for renal recovery after acute kidney injury.

Acute kidney injury (AKI) is a global public health concern with high mortality and morbidity. In ischemic-reperfusion injury (IRI), a main cause of AKI, the brush border membrane of S3 proximal tubules (PT) is lost to the tubular lumen. How injured tubules reconstitute lost membrane lipids during renal recovery is not known. Here, we identified Mfsd2a, a sodium-dependent lysophosphatidylcholine (LPC) transporter, to be expressed specifically in the basolateral membrane of S3 PT. Using an in vivo activity probe for Mfsd2a, transport activity was found to be specific to the S3 PT. Mice with haploinsufficiency of Mfsd2a exhibited delayed recovery of renal function after acute IRI, with depressed urine osmolality and elevated levels of histological markers of damage, fibrosis, and inflammation, findings corroborated by transcriptomic analysis. Lipidomics revealed a deficiency in docosahexaenoic acid (DHA) containing phospholipids in Mfsd2a haploinsufficiency. Treatment of Mfsd2a haploinsufficient mice with LPC-DHA improved renal function and reduced markers of injury, fibrosis, and inflammation. Additionally, LPC-DHA treatment restored S3 brush border membrane architecture and normalized DHA-containing phospholipid content. These findings indicate that Mfsd2a-mediated transport of LPC-DHA is limiting for renal recovery after AKI and suggest that LPC-DHA could be a promising dietary supplement for improving recovery following AKI.

PAQR proteins and the evolution of a superpower: Eating all kinds of fats: Animals rely on evolutionarily conserved membrane homeostasis proteins to compensate for dietary variation.

Recently published work showed that members of the PAQR protein family are activated by cell membrane rigidity and contribute to our ability to eat a wide variety of diets. Cell membranes are primarily composed of phospholipids containing dietarily obtained fatty acids, which poses a challenge to membrane properties because diets can vary greatly in their fatty acid composition and could impart opposite properties to the cellular membranes. In particular, saturated fatty acids (SFAs) can pack tightly and form rigid membranes (like butter at room temperature) while unsaturated fatty acids (UFAs) form more fluid membranes (like vegetable oils). Proteins of the PAQR protein family, characterized by the presence of seven transmembrane domains and a cytosolic N-terminus, contribute to membrane homeostasis in bacteria, yeasts, and animals. These proteins respond to membrane rigidity by stimulating fatty acid desaturation and incorporation of UFAs into phospholipids and explain the ability of animals to thrive on diets with widely varied fat composition. Also see the video abstract here: https://youtu.be/6ckcvaDdbQg.

Growth of Enterococcus faecalis ∆plsX strains is restored by increased saturated fatty acid synthesis.

The Enterococcus faecalis acyl-acyl carrier protein (ACP) phosphate acyltransferase PlsX plays an important role in phospholipid synthesis and exogenous fatty acid incorporation. Loss of plsX almost completely blocks growth by decreasing de novo phospholipid synthesis, which leads to abnormally long-chain acyl chains in the cell membrane phospholipids. The ∆plsX strain failed to grow without supplementation with an appropriate exogenous fatty acid. Introduction of a ∆fabT mutation into the ∆plsX strain to increase fatty acid synthesis allowed very weak growth. The ∆plsX strain accumulated suppressor mutants. One of these encoded a truncated ß-ketoacyl-ACP synthase II (FabO) which restored normal growth and restored de novo phospholipid acyl chain synthesis by increasing saturated acyl-ACP synthesis. Saturated acyl-ACPs are cleaved by a thioesterase to provide free fatty acids for conversion to acyl-phosphates by the FakAB system. The acyl-phosphates are incorporated into position sn1 of the phospholipids by PlsY. We report the tesE gene encodes a thioesterase that can provide free fatty acids. However, we were unable to delete the chromosomal tesE gene to confirm that it is the responsible enzyme. TesE readily cleaves unsaturated acyl-ACPs, whereas saturated acyl-ACPs are cleaved much more slowly. Overexpression of an E. faecalis enoyl-ACP reductase either FabK or FabI which results in high levels of saturated fatty acid synthesis also restored the growth of the ∆plsX strain. The ∆plsX strain grew faster in the presence of palmitic acid than in the presence of oleic acid with improvement in phospholipid acyl chain synthesis. Positional analysis of the acyl chain distribution in the phospholipids showed that saturated acyl chains dominate the sn1-position indicating a preference for saturated fatty acids at this position. High-level production of saturated acyl-ACPs is required to offset the marked preference of the TesE thioesterase for unsaturated acyl-ACPs and allow the initiation of phospholipid synthesis.

Immunometabolism Modulation by Extracts from Pistachio Stalks Formulated in Phospholipid Vesicles.

Several studies have demonstrated the effectiveness of plant extracts against various diseases, especially skin disorders; namely, they exhibit overall protective effects. The Pistachio (Pistacia vera L.) is known for having bioactive compounds that can effectively contribute to a person's healthy status. However, these benefits may be limited by the toxicity and low bioavailability often inherent in bioactive compounds. To overcome these problems, delivery systems, such as phospholipid vesicles, can be employed. In this study, an essential oil and a hydrolate were produced from P. vera stalks, which are usually discarded as waste. The extracts were characterized by liquid and gas chromatography coupled with mass spectrometry and formulated in phospholipid vesicles intended for skin application. Liposomes and transfersomes showed small size (<100 nm), negative charge (approximately -15 mV), and a longer storage stability for the latter. The entrapment efficiency was determined via the quantification of the major compounds identified in the extracts and was >80%. The immune-modulating activity of the extracts was assayed in macrophage cell cultures. Most interestingly, the formulation in transfersomes abolished the cytotoxicity of the essential oil while increasing its ability to inhibit inflammatory mediators via the immunometabolic citrate pathway.

A Nanotechnological Approach to Exploit and Enhance the Bioactivity of an Extract from Onopordum illyricum L. Leaves.

Plant-derived products have been used for preventive and curative purposes from the ancient era to the present day. Several studies have demonstrated the efficacy of either multicomponent-based extracts, enriched fractions, or isolated bioactives. However, they often display low solubility and bioavailability, chemical instability, poor absorption, and even toxicity, which restrict application in therapy. The use of drug delivery systems, especially nanocarriers, can overcome these physicochemical and pharmacokinetic limitations. In this study, an extract from Onopordum illyricum leaves was produced by maceration in 80% ethanol, characterized by liquid chromatography coupled to mass spectrometry, and formulated in phospholipid vesicles with the aim of exploiting and possibly enhancing its bioactivity for skin delivery. The results showed that phenolic compounds were abundantly present in the extract, especially hydroxycinnamic acid and flavonol derivatives. The extract-loaded vesicles showed small size (<100 nm), high entrapment efficiency (even >90% for most phenolic compounds), and good long-term stability. Moreover, the extract-loaded vesicles exhibited remarkable antioxidant activity, as demonstrated by colorimetric assays and by enhanced reduction of intracellular reactive oxygen species (ROS) levels in cultured skin cells. Hence, our findings support the key role of nanotechnological approaches to promote the potential of plant extracts and strengthen their application in therapy.