Human breast milk-derived phospholipid DOPE ameliorates intestinal injury associated with NEC by inhibiting ferroptosis.

Neonatal necrotizing enterocolitis (NEC) is a severe inflammatory bowel disease that commonly affects premature infants. Breastfeeding has been proven to be one of the most effective methods for preventing NEC. However, the specific role of lipids, the second major nutrient category in human breast milk (HBM), in intestinal development remains unclear. Our preliminary lipidomic analysis of the HBM lipidome revealed that dioleoyl phosphatidylethanolamine (DOPE) is not only abundant but also shows high solubility in lipids, endowing it with significant biological utility. Experimental results confirmed that DOPE significantly reduces the mortality of neonatal rats, ameliorates impairment of intestinal barrier function, and alleviates the expression of intestinal inflammatory factors IL-1ß and IL-6. Furthermore, DOPE promotes the migration and proliferation of intestinal epithelial cells, thereby enhancing the integrity of the intestinal barrier function in vitro. The progression of NEC is linked with the onset of ferroptosis. Our cellular-level analysis of lipid peroxide and iron ion concentrations revealed that DOPE significantly reduces the indicators of ferroptosis, while also modulating the expression of pivotal ferroptosis-associated factors, including SLC7A11, GPX4, and ACSL4. Hence, this research on DOPE is expected to provide novel insights into the bioactive lipids present in HBM.

Cardioprotection by Preconditioning with Intralipid Is Sustained in a Model of Endothelial Dysfunction for Isolated-Perfused Hearts.

Endothelial dysfunction (ED) is closely associated with most cardiovascular diseases. Experimental models are needed to analyze the potential impact of ED on cardioprotection in constant pressure Langendorff systems (CPLS). One cardioprotective strategy against ischemia/reperfusion injury (I/RI) is conditioning with the lipid emulsion Intralipid (IL). Whether ED modulates the cardioprotective effect of IL remains unknown. The aim of the study was to transfer a protocol using a constant flow Langendorff system for the induction of ED into a CPLS, without the loss of smooth muscle cell functionality, and to analyze the cardioprotective effect of IL against I/RI under ED. In isolated hearts of male Wistar rats, ED was induced by 10 min perfusion of a Krebs-Henseleit buffer containing 60 mM KCl (K+), and the vasodilatory response to the vasodilators histamine (endothelial-dependent) and sodium-nitroprusside (SNP, endothelial-independent) was measured. A CPLS was employed to determine cardioprotection of pre- or postconditioning with 1% IL against I/RI. The constant flow perfusion of K+ reduced endothelial response to histamine but not to SNP, indicating reduced vasodilatory functionality of endothelial cells but not smooth muscle cells. Preconditioning with IL reduced infarct size and improved cardiac function while postconditioning with IL had no effect. The induction of ED neither influenced infarct size nor affected the cardioprotective effect by preconditioning with IL. This protocol allows for studies of cardioprotective strategies under ED in CLPS. The protection by preconditioning with IL seems to be mediated independently of a functional endothelium.

The anticancer potential of tetrahydrocurcumin-phytosomes against oral carcinoma progression.

BACKGROUND: Herbal medicine combined with nanotechnology offers an alternative to the increasing burden of surgery and/or chemotherapy, the main therapeutics of oral carcinoma. Phytosomes are nano-vesicular systems formed by the interaction between phospholipids and phyto-active components via hydrogen bonding, exhibiting superior efficacy over pure phytocomponents in drug delivery. METHODS: Tetrahydrocurcumin (THC)-phytosomes were prepared by thin film hydration method. After characterization, in vitro cytotoxicity, antiproliferative capacity, antioxidant potential and full apoptotic workup were paneled on oral squamous cell carcinoma (SCC4) in comparison with native THC-solution and cisplatin (3.58 µg/mL intravenous injection), as positive controls. In addition, we tested the three medications on normal oral keratinocytes and gingival fibroblasts to attest to their tissue-selectivity. RESULTS: Successful preparation of THC-phytosomes using 1:1 molar ratio of THC to phospholipid exhibited significantly increased aqueous solubility, good colloidal properties, and complete drug release after one hour. On SCC4 cells, THC-phytosomes, at their dose-/time-dependency at ~ 60.06 µg/mL escalated cell percentages in the S-phase with 32.5 ± 6.22% increase, as well as a startling 29.69 ± 2.3% increase in apoptotic population. Depletion of the cell colonies survival to 0.29 ± 0.1% together with restraining the migratory rate by -6.4 ± 6.8% validated THC-phytosomes' antiproliferative capacity. Comparatively, the corresponding results of THC-solution and cisplatin revealed 12.9 ± 0.9% and 25.8 ± 1.1% for apoptosis and 0.9 ± 0.1% and 0.7 ± 0.08% for colony survival fraction, respectively. Furthermore, the nanoformulation exhibited the strongest immuno-positivity to caspase-3, which positively correlated with intense mitochondrial fluorescence by Mitotracker Red, suggesting its implication in the mitochondrial pathway of apoptosis, a finding further explained by the enormously high Bax and caspase-8 expression by RT-qPCR. Finally, the THC groups showed the lowest oxidative stress index, marking their highest free radical-scavenging potential among the test groups. CONCLUSIONS: THC-phytosomes are depicted to be an efficient nanoformulation that enhanced the anticancer efficacy over the free drug counterpart and the conventional chemotherapeutic. Additionally, being selective to cancer cells and less cytotoxic to normal cells makes THC-phytosomes a potential candidate for tissue-targeted therapy.

Effect of lipid emulsion on vasoconstriction induced by epinephrine or norepinephrine in isolated rat aorta.

BACKGROUND: Epinephrine (EPI) or norepinephrine (NOR) is widely used to treat cardiovascular collapse during lipid emulsion (LE) resuscitation for drug toxicity. However, the effect of LE on the vasoconstriction caused by EPI or NOR remains unknown. The purpose of this study was to examine the effect of an LE (Intralipid) on the vasoconstriction caused by EPI and NOR in isolated rat aorta. METHODS: The effect of LE on the vasoconstriction caused by EPI or NOR in isolated rat aorta was examined. Additionally, the effect of LE on the calcium increase caused by EPI or NOR was investigated. The distribution constant (KD: lipid to aqueous phase) of EPI or NOR between a LE (1%) and an aqueous phase was determined. RESULTS: LE (1 and 2%) did not significantly alter vasoconstriction caused by EPI or NOR in isolated endothelium-intact aorta. Moreover, the LE did not significantly alter the increased calcium level caused by EPI or NOR. The log KD of EPI in the LE (1%) was -0.71, -0.99, and -1.00 at 20, 50, and 100 mM ionic strength, respectively. The log KD of NOR in the LE (1%) was -1.22, -1.25, and -0.96 at 20, 50, and 100 mM ionic strength, respectively. CONCLUSIONS: Taken together, the Intralipid emulsion did not alter vasoconstriction induced by EPI or NOR that seems to be due to the hydrophilicity of EPI or NOR, leading to sustained hemodynamic support produced by EPI or NOR used during LE resuscitation.

The Synthetic Surfactant CHF5633 Restores Lung Function and Lung Architecture in Severe Acute Respiratory Distress Syndrome in Adult Rabbits.

PURPOSE: Acute respiratory distress syndrome (ARDS) is a major cause of hypoxemic respiratory failure in adults. In ARDS extensive inflammation and leakage of fluid into the alveoli lead to dysregulation of pulmonary surfactant metabolism and function. Altered surfactant synthesis, secretion, and breakdown contribute to the clinical features of decreased lung compliance and alveolar collapse. Lung function in ARDS could potentially be restored with surfactant replacement therapy, and synthetic surfactants with modified peptide analogues may better withstand inactivation in ARDS alveoli than natural surfactants. METHODS: This study aimed to investigate the activity in vitro and the bolus effect (200 mg phospholipids/kg) of synthetic surfactant CHF5633 with analogues of SP-B and SP-C, or natural surfactant Poractant alfa (Curosurf®, both preparations Chiesi Farmaceutici S.p.A.) in a severe ARDS model (the ratio of partial pressure arterial oxygen and fraction of inspired oxygen, P/F ratio ≤ 13.3 kPa) induced by hydrochloric acid instillation followed by injurious ventilation in adult New Zealand rabbits. The animals were ventilated for 4 h after surfactant treatment and the respiratory parameters, histological appearance of lung parenchyma and levels of inflammation, oxidative stress, surfactant dysfunction, and endothelial damage were evaluated. RESULTS: Both surfactant preparations yielded comparable improvements in lung function parameters, reductions in lung injury score, pro-inflammatory cytokines levels, and lung edema formation compared to untreated controls. CONCLUSIONS: This study indicates that surfactant replacement therapy with CHF5633 improves lung function and lung architecture, and attenuates inflammation in severe ARDS in adult rabbits similarly to Poractant alfa. Clinical trials have so far not yielded conclusive results, but exogenous surfactant may be a valid supportive treatment for patients with ARDS given its anti-inflammatory and lung-protective effects.

Oxysterols in Cell Viability, Phospholipidosis and Extracellular Vesicles Production in a Lung Cancer Model.

The study carried out systematic research on the influence of selected oxysterols on cells viability, phospholipidosis and the level of secreted extracellular vesicles. Three oxidized cholesterol derivatives, namely 7α-hydroxycholesterol (7α-OH), 7- ketocholesterol (7-K) and 24(S)-hydroxycholesterol (24(S)-OH) were tested in three different concentrations: 50 µM, 100 µM and 200 µM for 24 h incubation with A549 lung cancer cell line. All the studied oxysterols were found to alter cells viability. The lowest survival rate of the cells was observed after 24 h of 7-K treatment, slightly better for 7α-OH while cells incubated with 24(S)-OH had the best survival rate among the oxysterols used. 7-K increased phospholipids accumulation in cells, however, most noticeable effect was noticed for 24(S)-OH. Changes in the level of extracellular vesicles secreted in cells culture after the treatment with oxysterols were also observed. It was found that all oxysterols used increased the level of secreted vesicles, both exosomes and ectosomes. The strongest effect was noticed for 24(S)-OH. Taken together, these results suggest that 7-K is the most potent inducer of cancer cell death, while 7α-OH is slightly less potent in this respect. The lower cytotoxic effect of 24(S)-OH correlates with greater phospholipids accumulation, extracellular vesicles production and better cells survival.

Parenteral nutrition emulsion inhibits CYP3A4 in an iPSC derived liver organoids testing platform.

OBJECTIVES: Parenteral nutrition (PN) is used for patients of varying ages with intestinal failure to supplement calories. Premature newborns with low birth weight are at a high risk for developing PN associated liver disease (PNALD) including steatosis, cholestasis, and gallbladder sludge/stones. To optimize nutrition regimens, models are required to predict PNALD. METHODS: We have exploited induced pluripotent stem cell derived liver organoids to provide a testing platform for PNALD. Liver organoids mimic the developing liver and contain the different hepatic cell types. The organoids have an early postnatal maturity making them a suitable model for premature newborns. To mimic PN treatment we used medium supplemented with either clinoleic (80% olive oil/20% soybean oil) or intralipid (100% soybean oil) for 7 days. RESULTS: Homogenous HNF4a staining was found in all organoids and PN treatments caused accumulation of lipids in hepatocytes. Organoids exhibited a dose dependent decrease in CYP3A4 activity and expression of hepatocyte functional genes. The lipid emulsions did not affect overall organoid viability and glucose levels had no contributory effect to the observed results. CONCLUSIONS: Liver organoids could be utilized as a potential screening platform for the development of new, less hepatotoxic PN solutions. Both lipid treatments caused hepatic lipid accumulation, a significant decrease in CYP3A4 activity and a decrease in the RNA levels of both CYP3A4 and CYP1A2 in a dose dependent manner. The presence of high glucose had no additive effect, while Clinoleic at high dose, caused significant upregulation of interleukin 6 and TLR4 expression.

Z-Ligustilide Combined with Cisplatin Reduces PLPP1-Mediated Phospholipid Synthesis to Impair Cisplatin Resistance in Lung Cancer.

Lung cancer is a malignant tumor with one of the highest morbidity and mortality rates in the world. Approximately 80-85% of lung cancer is diagnosed as non-small lung cancer (NSCLC), and its 5-year survival rate is only 21%. Cisplatin is a commonly used chemotherapy drug for the treatment of NSCLC. Its efficacy is often limited by the development of drug resistance after long-term treatment. Therefore, determining how to overcome cisplatin resistance, enhancing the sensitivity of cancer cells to cisplatin, and developing new therapeutic strategies are urgent clinical problems. Z-ligustilide is the main active ingredient of the Chinese medicine Angelica sinensis, and has anti-tumor activity. In the present study, we investigated the effect of the combination of Z-ligustilide and cisplatin (Z-ligustilide+cisplatin) on the resistance of cisplatin-resistant lung cancer cells and its mechanism of action. We found that Z-ligustilide+cisplatin decreased the cell viability, induced cell cycle arrest, and promoted the cell apoptosis of cisplatin-resistant lung cancer cells. Metabolomics combined with transcriptomics revealed that Z-ligustilide+cisplatin inhibited phospholipid synthesis by upregulating the expression of phospholipid phosphatase 1 (PLPP1). A further study showed that PLPP1 expression was positively correlated with good prognosis, whereas the knockdown of PLPP1 abolished the effects of Z-ligustilide+cisplatin on cell cycle and apoptosis. Specifically, Z-ligustilide+cisplatin inhibited the activation of protein kinase B (AKT) by reducing the levels of phosphatidylinositol 3,4,5-trisphosphate (PIP3). Z-ligustilide+cisplatin induced cell cycle arrest and promoted the cell apoptosis of cisplatin-resistant lung cancer cells by inhibiting PLPP1-mediated phospholipid synthesis. Our findings demonstrate that the combination of Z-Ligustilide and cisplatin is a promising approach to the chemotherapy of malignant tumors that are resistant to cisplatin.

Dietary Phospholipids Alleviate Diet-Induced Obesity in Mice: Which Fatty Acids and Which Polar Head.

The weight loss effects of dietary phospholipids have been extensively studied. However, little attention has been paid to the influence of phospholipids (PLs) with different fatty acids and polar headgroups on the development of obesity. High-fat-diet-fed mice were administrated with different kinds of PLs (2%, w/w) with specific fatty acids and headgroups, including EPA-enriched phosphatidylcholine/phosphatidylethanolamine/phosphatidylserine (EPA-PC/PE/PS), DHA-PC/PE/PS, Egg-PC/PE/PS, and Soy-PC/PE/PS for eight weeks. Body weight, white adipose tissue weight, and the levels of serum lipid and inflammatory markers were measured. The expression of genes related to lipid metabolism in the liver were determined. The results showed that PLs decreased body weight, fat storage, and circulating lipid levels, and EPA-PLs had the best efficiency. Serum TNF-α, MCP-1 levels were significantly reduced via treatment with DHA-PLs and PS groups. Mechanistic investigation revealed that PLs, especially EPA-PLs and PSs, reduced fat accumulation through enhancing the expression of genes involved in fatty acid ß-oxidation (Cpt1a, Cpt2, Cd36, and Acaa1a) and downregulating lipogenesis gene (Srebp1c, Scd1, Fas, and Acc) expression. These data suggest that EPA-PS exhibits the best effects among other PLs in terms of ameliorating obesity, which might be attributed to the fatty acid composition of phospholipids, as well as their headgroup.

Insight into the Mechanism of Interactions between the LL-37 Peptide and Model Membranes of Legionella gormanii Bacteria.

Legionella gormanii is a fastidious, Gram-negative bacterium known to be the etiological agent of atypical community-acquired pneumonia. The human cathelicidin LL-37 exhibits a dose-dependent bactericidal effect on L. gormanii. The LL-37 peptide at the concentration of 10 µM causes the bacteria to become viable but not cultured. The antibacterial activity of the peptide is attributed to its effective binding to the bacterial membrane, as demonstrated by the fluorescence lifetime imaging microscopy. In this study, to mimic the L. gormanii membranes and their response to the antimicrobial peptide, Langmuir monolayers were used with the addition of the LL-37 peptide to the subphase of the Langmuir trough to represent the extracellular fluid. The properties of the model membranes (Langmuir monolayers) formed by phospholipids (PL) isolated from the L. gormanii bacteria cultured on the non-supplemented (PL-choline) and choline-supplemented (PL+choline) medium were determined, along with the effect of the LL-37 peptide on the intermolecular interactions, packing, and ordering under the monolayer compression. Penetration tests at the constant surface pressure were carried out to investigate the mechanism of the LL-37 peptide action on the model membranes. The peptide binds to the anionic bacterial membranes preferentially, due to its positive charge. Upon binding, the LL-37 peptide can penetrate into the hydrophobic tails of phospholipids, destabilizing membrane integrity. The above process can entail membrane disruption and ultimately cell death. The ability to evoke such a great membrane destabilization is dependent on the share of electrostatic, hydrogen bonding and Lifshitz-van der Waals LL-37-PL interactions. Thus, the LL-37 peptide action depends on the changes in the lipid membrane composition caused by the utilization of exogenous choline by the L. gormanii.

Truncated oxidized phospholipids exacerbate endothelial dysfunction and lung injury caused by bacterial pathogens.

Oxidized phospholipids (OxPLs) are present at basal levels in circulation of healthy individuals, but a substantial increase and changes in composition of OxPLs may rapidly occur during microbial infections, sepsis, and trauma. Specifically, truncated oxidized phospholipids (Tr-OxPLs) exhibit detrimental effects on pulmonary endothelium, yet their role on modulation of lung injury caused by bacterial pathogens remains to be elucidated. This study investigated the effects of Tr-OxPL species: KOdiA-PC, POV-PC, PON-PC, PAz-PC, PGPC, and Lyso-PC on endothelial permeability and inflammatory responses to gram-positive bacterial particles. Results showed that all six tested Tr-OxPLs augmented endothelial barrier disruption caused by heat-killed Staphylococcus aureus (HKSA) as determined by VE-cadherin immunostaining and monitoring transendothelial electrical resistance. In parallel, even moderate elevation of Tr-OxPLs augmented HKSA-induced activation of NF-κB, secretion of IL-6 and IL-8, and protein expression of ICAM-1 and VCAM-1. In the mouse model of acute lung injury caused by intranasal injection of HKSA, intravenous Tr-OxPLs administration augmented HKSA-induced increase in BAL protein content and cell counts, tissue expression of TNFα, KC, IL1ß, and CCL2, and promoted vascular leak monitored by lung infiltration of Evans Blue. These results suggest that elevated Tr-OxPLs act as critical risk factor worsening bacterial pathogen-induced endothelial dysfunction and lung injury.

QbD-Optimized, Phospholipid-Based Elastic Nanovesicles for the Effective Delivery of 6-Gingerol: A Promising Topical Option for Pain-Related Disorders.

In this study, elastic nanovesicles, constructed of phospholipids optimized by Quality by Design (QbD), release 6-gingerol (6-G), a natural chemical that may alleviate osteoporosis and musculoskeletal-related pain. A 6-gingerol-loaded transfersome (6-GTF) formulation was developed using a thin film and sonication approach. 6-GTFs were optimized using BBD. Vesicle size, PDI, zeta potential, TEM, in vitro drug release, and antioxidant activity were evaluated for the 6-GTF formulation. The optimized 6-GTF formulation had a 160.42 nm vesicle size, a 0.259 PDI, and a -32.12 mV zeta potential. TEM showed sphericity. The 6-GTF formulation's in vitro drug release was 69.21%, compared to 47.71% for the pure drug suspension. The Higuchi model best described 6-G release from transfersomes, while the Korsmeyer-Peppas model supported non-Fickian diffusion. 6-GTF had more antioxidant activity than the pure 6-G suspension. The optimized transfersome formulation was converted into a gel to improve skin retention and efficacy. The optimized gel had a spreadability of 13.46 ± 4.42 g·cm/s and an extrudability of 15.19 ± 2.01 g/cm2. The suspension gel had a 1.5 µg/cm2/h ex vivo skin penetration flux, while the 6-GTF gel had 2.71 µg/cm2/h. Rhodamine B-loaded TF gel reached deeper skin layers (25 µm) compared to the control solution in the CLSM study. The gel formulation's pH, drug concentration, and texture were assessed. This study developed QbD-optimized 6-gingerol-loaded transfersomes. 6-GTF gel improved skin absorption, drug release, and antioxidant activity. These results show that the 6-GTF gel formulation has the ability to treat pain-related illnesses effectively. Hence, this study offers a possible topical treatment for conditions connected to pain.

Lipid Emulsion Inhibits Amlodipine-Induced Nitric Oxide-Mediated Vasodilation in Isolated Rat Aorta.

This study aimed to examine the effect of lipid emulsion on the vasodilation induced by a toxic dose of amlodipine in isolated rat aorta and elucidate its mechanism, with a particular focus on nitric oxide. The effects of endothelial denudation, NW-nitro-L-arginvine methyl ester (L-NAME), methylene blue, lipid emulsion, and linolenic acid on the amlodipine-induced vasodilation and amlodipine-induced cyclic guanosine monophosphate (cGMP) production were examined. Furthermore, the effects of lipid emulsion, amlodipine, and PP2, either alone or combined, on endothelial nitric oxide synthase (eNOS), caveolin-1, and Src-kinase phosphorylation were examined. Amlodipine-induced vasodilation was higher in endothelium-intact aorta than in endothelium-denuded aorta. L-NAME, methylene blue, lipid emulsion, and linolenic acid inhibited amlodipine-induced vasodilation and amlodipine-induced cGMP production in the endothelium-intact aorta. Lipid emulsion reversed the increased stimulatory eNOS (Ser1177) phosphorylation and decreased inhibitory eNOS (Thr495) phosphorylation induced via amlodipine. PP2 inhibited stimulatory eNOS, caveolin-1, and Src-kinase phosphorylation induced via amlodipine. Lipid emulsion inhibited amlodipine-induced endothelial intracellular calcium increase. These results suggest that lipid emulsion attenuated the vasodilation induced via amlodipine through inhibiting nitric oxide release in isolated rat aorta, which seems to be mediated via reversal of stimulatory eNOS (Ser1177) phosphorylation and inhibitory eNOS (Thr495) dephosphorylation, which are also induced via amlodipine.

Itraconazole Modulates Phospholipid Levels in Tumor-associated Macrophages.

BACKGROUND/AIM: Itraconazole, an antifungal drug, repolarizes pro-tumorigenic M2 tumor-associated macrophages to anti-tumorigenic M1-like phenotypes, thereby inhibiting the proliferation of cancer cells; however, the underlying mechanism remains unclear. Therefore, we investigated the effect of itraconazole on membrane-associated lipids in tumor-associated macrophages (TAM). MATERIALS AND METHODS: M1 and M2 macrophages were derived from the human monocyte leukemia cell line (THP-1) and cultured with or without 10 µM itraconazole. Cells were homogenized and subjected to liquid chromatography/mass spectrometry (LC/MS) analysis to estimate the glycerophospholipid levels in the cells. RESULTS: Lipidomic analysis results, displayed on a volcano plot, revealed that itraconazole-induced altered phospholipid composition, with more pronounced changes in M2 macrophages than in M1. Notably, itraconazole significantly increased intracellular phosphatidylinositol and lysophosphatidylcholine levels in M2 macrophages. CONCLUSION: Itraconazole modulates the lipid metabolism of TAMs, which could have implications for the development of novel cancer therapies.

Membrane lipid changes in mouse blastocysts induced by ovarian stimulation, IVF and oocyte vitrification.

RESEARCH QUESTION: Is the membrane lipid profile of mice blastocysts affected by ovarian stimulation, IVF and oocyte vitrification? Could supplementation of vitrification media with L-carnitine and fatty acids prevent membrane phospholipid changes in blastocysts from vitrified oocytes? DESIGN: Experimental study comparing the lipid profile of murine blastocysts produced from natural mating, superovulated cycles or after IVF submitted or not to vitrification. For in-vitro experiments, 562 oocytes from superovulated females were randomly divided into four groups: fresh oocytes fertilized in vitro and vitrified groups: Irvine Scientific (IRV); Tvitri-4 (T4) or T4 supplemented with L-carnitine and fatty acids (T4-LC/FA). Fresh or vitrified-warmed oocytes were inseminated and cultured for 96 h or 120 h. The lipid profile of nine of the best quality blastocysts from each experimental group was assessed by multiple reaction monitoring profiling method. Significantly different lipids or transitions between groups were found using univariate statistics (P < 0.05; fold change = 1.5) and multivariate statistical methods. RESULTS: A total of 125 lipids in blastocysts were profiled. Statistical analysis revealed several classes of phospholipids affected in the blastocysts by ovarian stimulation, IVF, oocyte vitrification, or all. L-carnitine and fatty acid supplements prevented, to a certain extent, changes in phospholipid and sphingolipid contents in the blastocysts. CONCLUSION: Ovarian stimulation alone, or in association with IVF, promoted changes in phospholipid profile and abundance of blastocysts. A short exposure time to the lipid-based solutions during oocyte vitrification was sufficient to induce changes in the lipid profile that were sustained until the blastocyst stage.

Maturation of the malarial phosphatidylserine decarboxylase is mediated by high affinity binding to anionic phospholipids.

Decarboxylation of phosphatidylserine (PS) to form phosphatidylethanolamine by PS decarboxylases (PSDs) is an essential process in most eukaryotes. Processing of a malarial PSD proenzyme into its active alpha and beta subunits is by an autoendoproteolytic mechanism regulated by anionic phospholipids, with PS serving as an activator and phosphatidylglycerol (PG), phosphatidylinositol, and phosphatidic acid acting as inhibitors. The biophysical mechanism underlying this regulation remains unknown. We used solid phase lipid binding, liposome-binding assays, and surface plasmon resonance to examine the binding specificity of a processing-deficient Plasmodium PSD (PkPSDS308A) mutant enzyme and demonstrated that the PSD proenzyme binds strongly to PS and PG but not to phosphatidylethanolamine and phosphatidylcholine. The equilibrium dissociation constants (Kd) of PkPSD with PS and PG were 80.4 nM and 66.4 nM, respectively. The interaction of PSD with PS is inhibited by calcium, suggesting that the binding mechanism involves ionic interactions. In vitro processing of WT PkPSD proenzyme was also inhibited by calcium, consistent with the conclusion that PS binding to PkPSD through ionic interactions is required for the proenzyme processing. Peptide mapping identified polybasic amino acid motifs in the proenzyme responsible for binding to PS. Altogether, the data demonstrate that malarial PSD maturation is regulated through a strong physical association between PkPSD proenzyme and anionic lipids. Inhibition of the specific interaction between the proenzyme and the lipids can provide a novel mechanism to disrupt PSD enzyme activity, which has been suggested as a target for antimicrobials, and anticancer therapies.

Dimethyl-α-cyclodextrin induces capacitation by removing phospholipids from the plasma membrane of mouse sperm†.

Capacitation is an important event in the completion of fertilization by mammalian sperm. Cholesterol efflux is a trigger of capacitation. In general, cholesterol acceptors of albumin and ß-cyclodextrins are used to induce capacitation during in vitro fertilization. Previously, we reported that methyl-ß-cyclodextrin (MBCD), which is composed of seven glucoses, had a higher ability to induce capacitation than bovine serum albumin (BSA) in frozen-thawed mouse sperm. Comparison of albumin and cyclodextrins is helpful for understanding the mechanism of capacitation. In this study, we examined the effects of albumin, MBCD, and a different type of cyclodextrin, dimethyl-α-cyclodextrin (DMACD), which is composed of six glucoses, on several events of sperm capacitation. We showed that DMACD induced sperm capacitation and promoted fertilization ability. The time required to increase the fertilization rate differed among BSA, MBCD, and DMACD. BSA and MBCD enhanced cholesterol and phospholipid efflux, whereas DMACD enhanced only phospholipid efflux. BSA, MBCD, and DMACD increased sperm membrane fluidity, rearrangement of the lipid raft, and the acrosome reaction. These findings suggest that phospholipid efflux is a novel trigger of capacitation. Increasing the choice of sperm capacitation inducers may be useful for improving in vitro fertilization (IVF) techniques not only in mice, but also in various species in which it has been difficult to produce embryos by IVF.

The Curcumin Derivative GT863 Protects Cell Membranes in Cytotoxicity by Aß Oligomers.

In Alzheimer's disease (AD), accumulation of amyloid ß-protein (Aß) is one of the major mechanisms causing neuronal cell damage. Disruption of cell membranes by Aß has been hypothesized to be the important event associated with neurotoxicity in AD. Curcumin has been shown to reduce Aß-induced toxicity; however, due to its low bioavailability, clinical trials showed no remarkable effect on cognitive function. As a result, GT863, a derivative of curcumin with higher bioavailability, was synthesized. The purpose of this study is to clarify the mechanism of the protective action of GT863 against the neurotoxicity of highly toxic Aß oligomers (Aßo), which include high-molecular-weight (HMW) Aßo, mainly composed of protofibrils in human neuroblastoma SH-SY5Y cells, focusing on the cell membrane. The effect of GT863 (1 µM) on Aßo-induced membrane damage was assessed by phospholipid peroxidation of the membrane, membrane fluidity, membrane phase state, membrane potential, membrane resistance, and changes in intracellular Ca2+ ([Ca2+]i). GT863 inhibited the Aßo-induced increase in plasma-membrane phospholipid peroxidation, decreased membrane fluidity and resistance, and decreased excessive [Ca2+]i influx, showing cytoprotective effects. The effects of GT863 on cell membranes may contribute in part to its neuroprotective effects against Aßo-induced toxicity. GT863 may be developed as a prophylactic agent for AD by targeting inhibition of membrane disruption caused by Aßo exposure.

The Effect of Dietary Phospholipids on the Ultrastructure and Function of Intestinal Epithelial Cells.

Dietary composition substantially determines human health and affects complex diseases, including obesity, inflammation and cancer. Thus, food supplements have been widely used to accommodate dietary composition to the needs of individuals. Among the promising supplements are dietary phospholipids (PLs) that are commonly found as natural food ingredients and as emulsifier additives. The aim of the present study was to evaluate the effect of major PLs found as food supplements on the morphology of intestinal epithelial cells upon short-term and long-term high-dose feeding in mice. In the present report, the effect of short-term and long-term high dietary PL content was studied in terms of intestinal health and leaky gut syndrome in male mice. We used transmission electron microscopy to evaluate endothelial morphology at the ultrastructural level. We found mitochondrial damage and lipid droplet accumulation in the intracristal space, which rendered mitochondria more sensitive to respiratory uncoupling as shown by a mitochondrial respiration assessment in the intestinal crypts. However, this mitochondrial damage was insufficient to induce intestinal permeability. We propose that high-dose PL treatment impairs mitochondrial morphology and acts through extensive membrane utilization via the mitochondria. The data suggest that PL supplementation should be used with precaution in individuals with mitochondrial disorders.

Pharmacological heat-shock protein inducers and chemical chaperones inhibit upregulation of interleukin-8 by oxidized phospholipids.

Oxidised phospholipids such as oxidised palmitoyl-arachidonoyl-phosphatidylcholine (OxPAPC) are increasingly recognised as danger-associated molecular patterns (DAMPs) inducing cyto- and chemokines. The pathological impact of oxidised phosphatidylcholine in vivo has been demonstrated in several animal models, as well as in human association studies. In this work, we have tested a number of small molecules with known or potential anti-inflammatory properties for their ability to inhibit secretion of interleukin-8 by OxPAPC-treated endothelial cells. Six compounds capable of inhibiting the induction of IL-8 were selected. Analysis of gene expression has shown that all these substances reduced the OxPAPC-induced elevation of IL-8 mRNA but potentiated induction of heat-shock proteins (HSPs). We further found that drug-like HSP inducers also prevented the induction of IL-8 by OxPAPC. Similar inhibitory action was demonstrated by two chemical chaperones, which stabilise proteins through physicochemical mechanisms thus mimicking effects of HSPs. Our data suggest that proteostatic stress plays an important mechanistic role in the pro-inflammatory effects of OxPAPC and that stabilisation of proteome by overexpression of HSPs or by chemical chaperones can reduce the pro-inflammatory effects of OxPLs.