Lysophosphatidylcholine Research Articles

Mass spectrometry-based metabolomics reveals metabolism of molnupiravir may lead to metabolic disorders and hepatotoxicity.

Molnupiravir (MO) is a pyrimidine nucleoside anti-SARS-CoV-2 drug. MO treatment could cause mild liver injury. However, the underlying mechanism of MO-induced liver injury and the metabolic pathway of MO in vivo are unclear. In this study, metabolomics analysis and molecular biology methods were used to explore these issues. Through metabolomics analysis, it was found that the homeostasis of pyrimidine, purine, lysophosphatidylcholine (LPC), and amino acids in mice was destroyed after MO treatment. A total of 80 changed metabolites were detected. Among these changed metabolites, 4-ethylphenyl sulfate, dihydrouracil, and LPC 20:0 was related to the elevation of alkaline phosphatase (ALP), interleukin-6 (IL6), and nuclear factor kappa-B (NF-κB). The levels of 4-ethylphenyl sulfate, dihydrouracil, and LPC 20:0 in plasma were positively correlated with their levels in the liver, suggesting that these metabolites were associated with MO-induced liver injury. MO treatment could increase NHC and cytidine levels, activate cytidine deaminase (CDA), and increase LPC levels. CDA and LPC could increase the mRNA expression level of toll-like receptor (TLR). The current study indicated that the elevation of hepatic TLR may be an important reason for MO leading to the liver injury.

Healthy plasma lipidomic signatures depend on sex, age, body mass index, and contraceptives but not perceived stress.

Perceived stress is thought to contribute to the pathogenesis of metabolic, vascular, mental, and immune diseases, with different susceptibilities in women and men. The present study investigated if and how perceived stress and/or demographic variables including sex, age, body mass index, regular prescription drugs, occasional analgesics, or dietary supplements manifested in plasma lipidomic profiles, obtained by targeted and untargeted mass spectrometry analyses. The study included 217 healthy women and 108 healthy men, aged 18-68 years, who were recruited in a 2:1 female:male ratio to account for women with/without contraceptives. As expected, dehydroepiandrosterone sulfate (DHEAS) and ceramides were higher in men than women, and DHEAS decreased with age, while ceramides increased. Contrary to expectations, neither DHEAS nor ceramides were associated with perceived stress (PSQ30 questionnaire), which was however, associated with BMI in men, but not in women. None of the lipid species or classes showed a similar "age X sex X BMI" interaction, but the endocannabinoid palmitoylethanolamide (PEA) correlated with BMI and hypertension. Independent of perceived stress, lysophosphatidylcholines (LPCs) were lower in women than men, whereas LPC metabolites, lysophosphatidic acids (LPAs), were higher in women. The LPA:LPC ratio was particularly high in women using oral contraceptives suggesting a strong hormone-induced extracellular conversion of LPCs to LPAs, which is catalyzed by the phospholipase D, autotaxin. The results reveal complex sex differences in perceived stress and lipidomic profiles, the latter being exacerbated by contraceptive use, but perceived stress and lipids were not directly correlated.

Abdominal obesity in youth: the associations of plasma Lysophophatidylcholine concentrations with insulin resistance.

This study aimed to explore the associations of lysophosphatidylcholines (LPCs) with insulin resistance (IR) and abdominal obesity among children and adolescents. A cross-sectional study was conducted on 612 young individuals, aged 7 to 18 years in Tianjin City, China. LC-MS metabolomic analysis was used to measure LPCs levels. The Homeostasis Model Assessment was used to estimate IR. Waist circumference measurements were used to assess abdominal obesity. Logistic regression models were employed to explore the relationships between LPCs and IR and abdominal obesity. Mediation analyses were performed to analyze whether LPCs affected IR through abdominal obesity. Compared to their counterparts, five specific LPCs were significantly different in youth with IR. The levels of LPC 24:0 and 26:0 were significantly associated with IR after adjustment. Both decreased levels of LPC 24:0 and 26:0 associated with the increased risks of IR (OR: 0.64, 95%CI: 0.38-0.95; OR: 0.66, 95%CI: 0.40-1.00), and the ORs for abdominal obesity were 0.68 (95%CI: 0.38-1.00) and 0.51 (95%CI: 0.28-0.90), respectively. Mediation analysis indicated that abdominal obesity mediated the association between LPC 26:0 and IR, with a total effect (c) of -0.109 (P < 0.05), a direct effect (c') of -0.055 (P > 0.05), and an indirect effect through obesity (a × b) path with "a" of -0.125 (P < 0.05) and "b" of 0.426 (P < 0.05). Overall findings suggest that decreased levels of LPC 24:0 and 26:0 were associated with increased risks of IR and abdominal obesity. Importantly, addressing abdominal obesity may mediate the impact of IR driven by LPC 26:0.

Serum lipidome reveals lipid metabolic dysregulation in severe fever with thrombocytopenia syndrome

BackgroundSevere fever with thrombocytopenia syndrome (SFTS) is a rapidly progressing infectious disease with a high fatality rate caused by a novel bunyavirus (SFTSV). The role of lipids in viral infections is well-documented; however, the specific alterations in lipid metabolism during SFTSV infection remain elusive. This study aims to elucidate the lipid metabolic dysregulations in the early stages of SFTS patients.MethodsThis study prospectively collected peripheral blood sera from 11 critical SFTS patients, 37 mild SFTS patients, and 23 healthy controls during the early stages of infection for lipidomics analysis. A systematic bioinformatics analysis was conducted from three aspects integrating lipid differential expressions, lipid differential correlations, and lipid-clinical indices correlations to reveal the serum lipid metabolic dysregulation in SFTSV-infected individuals.ResultsOur findings reveal significant lipid metabolic dysregulation in SFTS patients. Specifically, compared to healthy controls, SFTS patients exhibited three distinct modes of lipid differential expression: increased levels of lipids including phosphatidylserine (PS), hexosylceramide (HexCer), and triglycerides (TG); decreased levels of lipids including lysophosphatidylcholine (LPC), acylcarnitine (AcCa), and cholesterol esters (ChE); and lipids showing “dual changes” including phosphatidylcholine (PC) and phosphatidylethanolamine (PE). Finally, based on lipid metabolic pathways and literature analysis, we systematically elucidated the potential mechanisms underlying lipid metabolic dysregulation in the early stage of SFTSV infection.ConclusionsOur study presents the first global serum lipidome profile and reveals the lipid metabolic dysregulation patterns in the early stage of SFTSV infection. These findings provide a new basis for the diagnosis, treatment, and further investigation of the disease.

Proteomic and metabolomic profiles of plasma-derived Extracellular Vesicles differentiate melanoma patients from healthy controls

BackgroundPlasma-derived Extracellular Vesicles (EVs) have been suggested as novel biomarkers in melanoma, due to their ability to reflect the cell of origin and ease of collection. This study aimed to identify novel EV biomarkers that can discriminate between disease stages. This was achieved by characterising the plasma-derived EVs of patients with melanoma, and comparing their proteomic and metabolomic profile to those from healthy controls. MethodsEVs were isolated from the plasma of 36 patients with melanoma and 13 healthy controls using Size Exclusion Chromatography. Proteomic and Metabolomic Analyses were performed, and machine learning algorithms were used to identify potential proteins and metabolites to differentiate the plasma-derived EVs from melanoma patients of different disease stages. ResultsThe concentration and size of the EV population isolated was similar between groups. Proteins (APOC4, PRG4, PLG, TNC, VWF and SERPIND1) and metabolites (lyso PC a C18:2, PC ae C44:3) previously associated with melanoma pathogenesis were identified as relevant in differentiating between disease stages. ConclusionThe results further support the continued investigation of circulating plasma-derived EVs as biomarkers in melanoma. Furthermore, the potential of combined proteo-metabolomic signatures for differentiation between disease stages may provide valuable insights into early detection, prognosis, and personalised treatment strategies.

Blood plasma lipid profile in glial tumors

Introduction. In glial tumors, lipid metabolism becomes abnormal. Analysis of lipid metabolism components can be an important characteristic of molecular and genetic profile of gliomas.Aim. To determine the correlation between plasma lipidome profile and immunohistochemical characteristics of glial tumors and to evaluate clinical significance of blood lipid spectrum analysis in preoperative assessment of molecular profile of gliomas.Materials and methods. Immunohistochemical measurement of O-6-methylguanine-DNA-methyl transferase (MGMT), Ki-67, p53, IDH1 tumor markers was performed using the corresponding antibody clones. Composition of plasma lipids was assessed using thin layer chromatography.Results. Even at the early stages of gliomagenesis, significant differences in cholesterol ethers, lysophosphatidylcholines, phosphatidylcholine (PC)/ lysophosphatidylcholine (LPC) ratio, neutral lipids (NL)/phospholipids (PL) in the blood were observed. Significant correlations between Ki-67, MGMT tumor markers and the above-mentioned lipidome parameters were found. The PC/LPC, NL/PL ratios in the blood of the patients from the groups with higher (above 10 %) and lower (below 10 %) Ki-67 mitotic indexes compared to healthy individuals were significantly lower. Therefore, the values of lipidome parameters allow to indirectly assess proliferative activity of gliomas which can be used for preoperative diagnosis of these tumors. No significant differences in the plasma PC/LPC and NL/PL ratios were found between the groups with MGMT promoter methylation and without it. No indirect predictor criteria for MGMT were found.Conclusion. It is impossible to determine decreased epigenetic activity of corresponding transcripts and preoperative prognosis for alkylating agent therapy based on the parameters of plasma lipid metabolism.

LC-MRM-MS-based lipidomics reveals differences in the digestion, absorption, and metabolism of phosphatidylcholines from Egg, Soy, and Krill in vivo

The acyl chain composition of dietary sources phosphatidylcholine (PC) is highly diverse. However, the effect of different PC intakes on the digestive products lysophosphatidylcholines (LPCs) and plasma metabolite species has not been elucidated. Here, LC-MRM-MS analysis was employed to identify and quantify 36 PC and 10 LPC molecular species in small intestinal contents, jejunum, plasma, and colonic contents within 12 h after administration of Egg-PC, Soy-PC, and Krill-PC. These results showed that the three PCs were rapidly hydrolyzed to LPCs within 0.5 h of reaching the small intestine, and the LPC species showed significant positive correlations with the corresponding fatty acid composition of the dietary PC. Notably, the abundance of plasma PUFA_PUFA PCs such as PC18:2_18:2 increased 5.8-fold after administration of Soy-PC for 2 h. Strikingly, administration of krill-PC for 2 h increased plasma LPC20:5 and PC16:0_20:5 by 23.6-fold and 26.6-fold, respectively, compared to 0 h, but the level of PC20:5_20:5 was low. In addition, correlation between the LPC species in small intestinal contents and plasma phospholipid species were analyzed, shedding light on the rules of re-esterification and absorption. These results could be useful for efficiently exploiting the nutritional functions of PCs with different acyl chains.

Perturbations in the blood metabolome up to a decade before prostate cancer diagnosis in 4387 matched case-control sets from the European Prospective Investigation into Cancer and Nutrition.

Measuring pre-diagnostic blood metabolites may help identify novel risk factors for prostate cancer. Using data from 4387 matched case-control pairs from the European Prospective Investigation into Cancer and Nutrition (EPIC) study, we investigated the associations of 148 individual metabolites and three previously defined metabolite patterns with prostate cancer risk. Metabolites were measured by liquid chromatography-mass spectrometry. Multivariable-adjusted conditional logistic regression was used to estimate the odds ratio per standard deviation increase in log metabolite concentration and metabolite patterns (OR1SD) for prostate cancer overall, and for advanced, high-grade, aggressive. We corrected for multiple testing using the Benjamini-Hochberg method. Overall, there were no associations between specific metabolites or metabolite patterns and overall, aggressive, or high-grade prostate cancer that passed the multiple testing threshold (padj <0.05). Six phosphatidylcholines (PCs) were inversely associated with advanced prostate cancer diagnosed at or within 10 years of blood collection. metabolite patterns 1 (64 PCs and three hydroxysphingomyelins) and 2 (two acylcarnitines, glutamate, ornithine, and taurine) were also inversely associated with advanced prostate cancer; when stratified by follow-up time, these associations were observed for diagnoses at or within 10 years of recruitment (OR1SD 0.80, 95% CI 0.66-0.96 and 0.76, 0.59-0.97, respectively) but were weaker after longer follow-up (0.95, 0.82-1.10 and 0.85, 0.67-1.06). Pattern 3 (8 lyso PCs) was associated with prostate cancer death (0.82, 0.68-0.98). Our results suggest that the plasma metabolite profile changes in response to the presence of prostate cancer up to a decade before detection of advanced-stage disease.

Exploring Lysophosphatidylcholine as a Biomarker in Ischemic Stroke: The Plasma-Brain Disjunction.

Lipids and their bioactive metabolites, notably lysophosphatidylcholine (LPC), are increasingly important in ischemic stroke research. Reduced plasma LPC levels have been linked to stroke occurrence and poor outcomes, positioning LPC as a potential prognostic or diagnostic marker. Nonetheless, the connection between plasma LPC levels and stroke severity remains unclear. This study aimed to elucidate this relationship by examining plasma LPC levels in conjunction with brain LPC levels to provide a deeper understanding of the underlying mechanisms. Adult male Sprague-Dawley rats underwent transient middle cerebral artery occlusion and were randomly assigned to different groups (sham-operated, vehicle, LPC supplementation, or LPC inhibition). We measured multiple LPC species in the plasma and brain, alongside assessing sensorimotor dysfunction, cerebral perfusion, lesion volume, and markers of BBB damage, inflammation, apoptosis, and oxidative stress. Among five LPC species, plasma LPC(16:0) and LPC(18:1) showed strong correlations with sensorimotor dysfunction, lesion severity, and mechanistic biomarkers in the rat stroke model. Despite notable discrepancies between plasma and brain LPC levels, both were strongly linked to functional outcomes and mechanistic biomarkers, suggesting that LPC's prognostic value is retained extracranially. This study advances the understanding of LPC as a blood marker in ischemic stroke and highlights directions for future research to further elucidate its association with stroke severity, particularly through investigations in more clinically representative models.

Sex-specific response of the human plasma lipidome to short-term cold exposure

Cold-induced lipolysis is widely studied as a potential therapeutic strategy to combat metabolic disease, but its effect on lipid homeostasis in humans remains largely unclear. Blood plasma comprises an enormous repertoire in lipids allowing insights into whole body lipid homeostasis. So far, reported results originate from studies carried out with small numbers of male participants. Here, the blood plasma's lipidome of 78 male and 93 female volunteers, who were exposed to cold below the shivering threshold for 2 h, was quantified by comprehensive lipidomics using high-resolution mass spectrometry. Short-term cold exposure increased the concentrations in 147 of 177 quantified circulating lipids and the response of the plasma's lipidome was sex-specific. In particular, the amounts of generated glycerophospholipid and sphingolipid species differed between the sexes. In women, the BMI could be related with the lipidome's response. A logistic regression model predicted with high sensitivity and specificity whether plasma samples were from male or female subjects based on the cold-induced response of phosphatidylcholine (PC), lysophosphatidylcholine (LPC), and sphingomyelin (SM) species.In summary, cold exposure promotes lipid synthesis by supplying fatty acids generated after lipolysis for all lipid classes. The plasma lipidome, i.e. PC, LPC and SM, shows a sex-specific response, indicating a different regulation of its metabolism in men and women. This supports the need for sex-specific research and avoidance of sex bias in clinical trials.

Lysophospholipid headgroup size, and acyl chain length and saturation differentially affect vacuole acidification, Ca 2+ transport, and fusion.

SNARE-mediated membrane fusion is regulated by the lipid composition of the engaged bilayers. Lipid composition impacts fusion through direct protein lipid interactions or through modulating the physical properties of membranes at the site of contact, including the induction of positive curvature by lysophospholipids (LPLs). The degree of positive curvature induced is due to the length and saturation of the single acyl chain in addition to the size of the head group. Here we examined how yeast vacuole fusion and ion transport were differentially affected by changes in lysolipid properties. We found that lysophosphatidylcholine (LPC) with acyl chains containing 14-18 carbons all inhibited fusion with IC 50 values ranging from ∼40-120 µM. The monounsaturation of LPC-18:1 had no effect when compared to its saturated counterpart LPC-18:0. On the other hand, head group size played a more significant role in blocking fusion as lysophosphatidic acid (LPA)-18:1 failed to fully inhibit fusion. We also show that both Ca 2+ uptake and SNARE-dependent Ca 2+ efflux was sensitive to changes in the acyl chain length and saturation of LPCs, while LPA only affected Ca 2+ efflux. Finally, we tested these LPLs on vacuole acidification by the V-ATPase. This showed that LPC-18:0 could fully inhibit acidification whereas other LPCs had moderate effects. Again, LPA had no effect. Together these data suggest that the effects of LPLs were due to a combination of head group size and acyl chain length leading to a range in degree of positive curvature.

Lyso-phosphatidylcholine as an interfacial stabilizer for parenteral monoclonal antibody formulations

Therapeutic proteins suffer from physical and chemical instability in aqueous solution. Polysorbates and poloxamers are often added for protection against interfacial stress to prevent protein aggregation and particle formation. Previous studies have revealed that the hydrolysis and oxidation of polysorbates in parenteral formulations can lead to the formation of free fatty acid particles, insufficient long-term stabilization, and protein oxidation. Poloxamers, on the other hand, are considered to be less effective against protein aggregation. Here we investigated two lyso-phosphatidylcholines (LPCs) as potential alternative surfactants for protein formulations, focusing on their physicochemical behavior and their ability to protect against the formation of monoclonal antibody particles during mechanical stress.The hemolytic activity of LPC was tested in varying ratios of plasma and buffer mixtures. LPC effectively stabilized mAb formulations when shaken at concentrations several orders of magnitude below the onset of hemolysis, indicating that the potential for erythrocyte damage by LPC is non-critical. LPC formulations subjected to mechanical stress through peristaltic pumping exhibited comparable protein particle formation to those containing polysorbate 80 or poloxamer 188. Profile analysis tensiometry and dilatational rheology indicated that the stabilizing effect likely arises from the formation of a viscoelastic film at approximately the CMC. Data gathered from concentration-gradient multi-angle light scattering and isothermal titration calorimetry support this finding. Surfactant desorption was evaluated through sub-phase exchange experiments. While LPCs readily desorbed from the interface, resorption occurred rapidly enough in the bulk solution to prevent protein adsorption. Overall, LPCs behave similarly to polysorbate with respect to interfacial stabilization and show promise as a potential substitute for polysorbate in parenteral protein formulations.

Abstract B036: Hypoxic cancer cells condition immunosuppressive macrophages via secreted non-protein mediators in pancreatic ductal adenocarcinoma

Abstract INTRODUCTION: Hypoxia is a defining feature of pancreatic ductal adenocarcinoma (PDAC) that contributes to the immunosuppressive microenvironment defined by increased tumor-associated macrophages (TAMs). However, there is an unmet need to define mechanisms by which hypoxia drives the immunosuppressive macrophage phenotype. We hypothesize that hypoxic cancer cells secrete non-protein metabolites to induce immunosuppressive phenotypes in macrophages. METHODS: We generated conditioned media (CM) by culturing the pancreatic adenocarcinoma cell line KPC under normoxia (21% O2) or hypoxia (0.5% O2) conditions for 48 hours. We treated bone marrow-derived macrophages (BMDMs) or the macrophage line RAW264.7 with CM. We assessed immunosuppressive gene expression using RNAseq and qRT-PCR. Proteins in CM were depleted using Sera-Mag Magnetic Carboxylate Modified Beads or denatured by boiling at 100°C for 15 minutes. We identified changes in metabolites between hypoxic and normoxic CM using HPLC. RESULTS: Compared to BMDMs treated with normoxic CM, we observed that BMDMs treated with hypoxic CM induced multiple immunosuppressive proteins (Arg1), cytokines (Ccl22, Cxcl3) and interleukins (Il1b, Il1a, Il6). Similarly, GSEA analysis demonstrated that hypoxic CM induced TNFa signaling via NfkB and IL6-JAK-STAT3 signaling. Consistent with RNA-seq analysis, qRT-PCR measured Arg1 expression 53 times higher in hypoxic CM-treated BMDMs compared to nomoxic CM (p=0.0286). Compared to normoxic CM, hypoxic CM stimulated macrophage migration, a marker for macrophage infiltration, as measured by transwell assays (p&amp;lt;0.0001). An increase in Arg1 expression in RAW264.7 cells was still observed when treated with protein depleted or boiled hypoxic CM, excluding proteins as soluble factor(s) mediating immunosuppression. To identify non-protein mediators of immune suppression, mass spectrometry quantified lipids and metabolites enriched in HCM. Metabolomic analysis identified 40 metabolites increased in hypoxic CM including the monounsaturated or polyunsaturated fatty acids linoelaidic acid, DGLA, and arachidonic acid. Similarly, lipidomic analysis revealed that multiple PC (phosphatidylcholine) and LPC (lysophosphatidylcholine) lipid species were enriched in HCM. CONCLUSION: We observe that hypoxic tumor cells induce immunosuppressive changes in macrophages likely via secreted non-protein metabolites. The hypoxic metabolome of PDAC tumor cells may be a key driver of the accumulation of immunosuppressive tumor associated macrophages. We are currently characterizing the role of individual lipids or metabolites in macrophage polarization. Citation Format: Matthew T Cribb, Sahar Fattani, Ayeisha Colon-Ortiz, Dadi Jiang, Michael Spiotto, Albert Koong. Hypoxic cancer cells condition immunosuppressive macrophages via secreted non-protein mediators in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr B036.

Abstract C038: Cancer-associated fibroblasts maintain critical pancreatic cancer cell lipid homeostasis in the tumor microenvironment

Abstract Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy whose abundant cancer-associated fibroblasts (CAFs) create a hallmark “desmoplasia” that severely limits oxygen and nutrient delivery. Hypoxia inhibits oxygen-dependent metabolic processes. For example, unsaturated lipid biosynthesis relies on oxygen to maintain desaturase enzymatic activities. Here, we investigated the mechanisms by which PDAC cells maintain lipid homeostasis under these conditions. Exogenous unsaturated lipids, rather than de novo synthesis, sustain PDAC cell viability by relieving endoplasmic reticulum (ER) stress under nutrient scarcity. Furthermore, CAFs are less hypoxic than adjacent malignant cells in vivo due to proximal blood vessel accessibility, nominating them as a potential source of these obligatory species. CAF-conditioned medium promoted PDAC cell survival upon nutrient and oxygen deprivation, an effect reversed by delipidation. We determined that lysophosphatidylcholines (LPCs) are particularly enriched in CAF-conditioned medium and preferentially taken up by PDAC cells, where they are converted to phosphatidylcholines (PCs) to sustain membrane integrity. Inhibiting LPC to PC conversion reversed the ability of exogenous unsaturated LPCs to sustain cancer cell survival and restrain ER stress in vitro and in vivo. Collectively, these results reveal a critical lipid cross-feeding mechanism enabling PDAC cell survival and identify an innovative approach to targeting this metabolic dependency. Efforts to target lipid crosstalk between CAFs and PDAC cells will be discussed. Citation Format: Xu Han, Michelle Burrows, Laura C Kim, Jimmy Xu, Will Vostrejs, Tran Ngoc Van Le, Yanqing Jiang, Edna Cukierman, Reiss Binder Kim, Ben Z Stanger, Clementina Mesaros, Brian Keith, Celeste Simon. Cancer-associated fibroblasts maintain critical pancreatic cancer cell lipid homeostasis in the tumor microenvironment [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr C038.

Investigation into temporal changes in the human bloodstain lipidome.

Bloodstains are crucial pieces of physical evidences found at violent crime scenes, providing valuable information for reconstructing forensic cases. However, there is limited data on how bloodstain lipidomes change over time after deposition. Hence, we deployed a high-throughput high-performance liquid chromatography-mass spectrometry (HPLC-MS) approach to construct lipidomic atlases of bloodstains, whole blood, plasma, and blood cells from 15 healthy adults. A time-course analysis was also performed on bloodstains deposited for up to 6months at room temperature (~ 25°C). The molecular levels of 60 out of 400 detected lipid species differed dramatically between bloodstain and whole blood samples, with major disturbances observed in membrane glycerophospholipids. More than half of these lipids were prevalent in the cellular and plasmic fractions; approximately 27% and 10% of the identified lipids were uniquely derived from blood cells and plasma, respectively. Furthermore, a subset of 65 temporally dynamic lipid species arose across the 6-month room-temperature deposition period, with decreased triacylglycerols (TAGs) and increased lysophosphatidylcholines (LPCs) as representatives, accounting for approximately 8% of the total investigated lipids. The instability of lipids increased linearly with time, with the most variability observed in the first 10days. This study sheds light on the impact of air-drying bloodstains on blood components at room temperature and provides a list of potential bloodstain lipid markers for determining the age of bloodstains.

Quercetin Mitigates Lysophosphatidylcholine (LPC)-Induced Neutrophil Extracellular Traps (NETs) Formation through Inhibiting the P2X7R/P38MAPK/NOX2 Pathway.

Neutrophil extracellular traps (NETs) are three-dimensional reticular structures that release chromatin and cellular contents extracellularly upon neutrophil activation. As a novel effector mechanism of neutrophils, NETs possess the capacity to amplify localized inflammation and have been demonstrated to contribute to the exacerbation of various inflammatory diseases, including cardiovascular diseases and tumors. It is suggested that lysophosphatidylcholine (LPC), as the primary active component of oxidized low-density lipoprotein, represents a significant risk factor for various inflammatory diseases, such as cardiovascular diseases and neurodegenerative diseases. However, the specific mechanism of NETs formation induced by LPC remains unclear. Quercetin has garnered considerable attention due to its anti-inflammatory properties, serving as a prevalent flavonoid in daily diet. However, little is currently known about the underlying mechanisms by which quercetin inhibits NETs formation and alleviates associated diseases. In our study, we utilized LPC-treated primary rat neutrophils to establish an in vitro model of NETs formation, which was subsequently subjected to treatment with a combination of quercetin or relevant inhibitors/activators. Compared to the control group, the markers of NETs and the expression of P2X7R/P38MAPK/NOX2 pathway-associated proteins were significantly increased in cells treated with LPC alone. Quercetin intervention decreased the LPC-induced upregulation of the P2X7R/P38MAPK/NOX2 pathway and effectively reduced the expression of NETs markers. The results obtained using a P2X7R antagonist/activator and P38MAPK inhibitor/activator support these findings. In summary, quercetin reversed the upregulation of the LPC-induced P2X7R/P38MAPK/NOX2 pathway, further mitigating NETs formation. Our study investigated the potential mechanism of LPC-induced NETs formation, elucidated the inhibitory effect of quercetin on NETs formation, and offered new insights into the anti-inflammatory properties of quercetin.

Fat burning capacity in a mixed macronutrient meal protocol does not reflect metabolic flexibility in women who are overweight or obese.

Metabolic flexibility, the ability to switch from glucose to fat as a fuel source, is considered a marker of metabolic health. Higher fat oxidation is often associated with greater flexibility and insulin sensitivity, while lower fat oxidation is linked to metabolic inflexibility and insulin resistance. However, our study challenges the universal validity of this relationship, uncovering a more nuanced understanding of the complex interplay between fuel source switching and fat oxidation, especially in the presence of insulin resistance. In an 8-week controlled feeding intervention, overweight to obese women with insulin resistance (as defined by McAuley's index) were randomized to consume either a diet based on the Dietary Guidelines for Americans 2010 (DGA) or a 'Typical' American Diet (TAD), n = 22 each. Participants were given a high-fat mixed macronutrient challenge test (MMCT) (60% fat, 28% carbohydrates, and 12% protein) at weeks 0, 2, and 8. Plasma lipids, metabolome, and lipidome were measured at 0, 0.5, 3, and 6h postprandial (PP); substrate oxidation measures were also recorded at 0,1 3, and 6h PP. Metabolic flexibility was evaluated as the change in fat oxidation from fasting to PP. Mixed model and multivariate analyses were used to evaluate the effect of diet on these outcomes, and to identify variables of interest to metabolic flexibility. Intervention diets (DGA and TAD) did not differentially affect substrate oxidation or metabolic flexibility, and equivalence tests indicated that groups could be combined for subsequent analyses. Participants were classified into three groups based on the % of consumed MMCT fat was oxidized in the 6h post meal period at weeks 0, 2 and 8. Low fat burners (LB, n = 6, burned <30% of fat in MMCT) and high fat burners (HB, n = 7, burned > 40% of fat in MMCT) at all weeks. Compared to LB, HB group had higher fat mass, total mass, lean mass, BMI, lower HDLc and lower RER (p < 0.05), but not different % body fat or % lean mass. During week 0, at 1h PP, LB had an increase in % fat oxidation change from 0h compared to HB (p<0.05), suggesting higher metabolic flexibility. This difference disappeared later in the PP phase, and we did not detect this beyond week 0. Partial least squares discriminant analysis (PLSDA (regular and repeated measures (sPLSDA)) models identified that LB group, in the late PP phase, was associated with higher rates of disappearance of acylcarnitines (AC) and lysophosphatidylcholines (LPC) from plasma (Q2: 0.20, R2X: 0.177, R2Y: 0.716). In women with insulin resistance, a high fat burning capacity does not imply high metabolic flexibility, and not all women with insulin resistance are metabolically inflexible. LPCs and ACs are promising biomarkers of metabolic flexibility.

Functional determinants of lysophospholipid- and voltage-dependent regulation of TRPC5 channel

Lysophosphatidylcholine (LPC) is a bioactive lipid present at high concentrations in inflamed and injured tissues where it contributes to the initiation and maintenance of pain. One of its important molecular effectors is the transient receptor potential canonical 5 (TRPC5), but the explicit mechanism of the activation is unknown. Using electrophysiology, mutagenesis and molecular dynamics simulations, we show that LPC-induced activation of TRPC5 is modulated by xanthine ligands and depolarizing voltage, and involves conserved residues within the lateral fenestration of the pore domain. Replacement of W577 with alanine (W577A) rendered the channel insensitive to strong depolarizing voltage, but LPC still activated this mutant at highly depolarizing potentials. Substitution of G606 located directly opposite position 577 with tryptophan rescued the sensitivity of W577A to depolarization. Molecular simulations showed that depolarization widens the lower gate of the channel and this conformational change is prevented by the W577A mutation or removal of resident lipids. We propose a gating scheme in which depolarizing voltage and lipid-pore helix interactions act together to promote TRPC5 channel opening.

Pathological characteristics of axons and alterations of proteomic and lipidomic profiles in midbrain dopaminergic neurodegeneration induced by WDR45-deficiency

BackgroundAlthough WD repeat domain 45 (WDR45) mutations have been linked to β\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\upbeta$$\\end{document}-propeller protein-associated neurodegeneration (BPAN), the precise molecular and cellular mechanisms behind this disease remain elusive. This study aims to shed light on the impacts of WDR45-deficiency on neurodegeneration, specifically axonal degeneration, within the midbrain dopaminergic (DAergic) system. We hope to better understand the disease process by examining pathological and molecular alterations, especially within the DAergic system.MethodsTo investigate the impacts of WDR45 dysfunction on mouse behaviors and DAergic neurons, we developed a mouse model in which WDR45 was conditionally knocked out in the midbrain DAergic neurons (WDR45cKO). Through a longitudinal study, we assessed alterations in the mouse behaviors using open field, rotarod, Y-maze, and 3-chamber social approach tests. We utilized a combination of immunofluorescence staining and transmission electron microscopy to examine the pathological changes in DAergic neuron soma and axons. Additionally, we performed proteomic and lipidomic analyses of the striatum from young and aged mice to identify the molecules and processes potentially involved in the striatal pathology during aging. Further more, primary midbrain neuronal culture was employed to explore the molecular mechanisms leading to axonal degeneration.ResultsOur study of WDR45cKO mice revealed a range of deficits, including impaired motor function, emotional instability, and memory loss, coinciding with the profound reduction of midbrain DAergic neurons. The neuronal loss, we observed massive axonal enlargements in the dorsal and ventral striatum. These enlargements were characterized by the accumulation of extensively fragmented tubular endoplasmic reticulum (ER), a hallmark of axonal degeneration. Proteomic analysis of the striatum showed that the differentially expressed proteins were enriched in metabolic processes. The carbohydrate metabolic and protein catabolic processes appeared earlier, and amino acid, lipid, and tricarboxylic acid metabolisms were increased during aging. Of note, we observed a tremendous increase in the expression of lysophosphatidylcholine acyltransferase 1 (Lpcat1) that regulates phospholipid metabolism, specifically in the conversion of lysophosphatidylcholine (LPC) to phosphatidylcholine (PC) in the presence of acyl-CoA. The lipidomic results consistently suggested that differential lipids were concentrated on PC and LPC. Axonal degeneration was effectively ameliorated by interfering Lpcat1 expression in primary cultured WDR45-deficient DAergic neurons, proving that Lpcat1 and its regulated lipid metabolism, especially PC and LPC metabolism, participate in controlling the axonal degeneration induced by WDR45 deficits.ConclusionsIn this study, we uncovered the molecular mechanisms underlying the contribution of WDR45 deficiency to axonal degeneration, which involves complex relationships between phospholipid metabolism, autophagy, and tubular ER. These findings greatly advance our understanding of the fundamental molecular mechanisms driving axonal degeneration and may provide a foundation for developing novel mechanistically based therapeutic interventions for BPAN and other neurodegenerative diseases.

Inhibitory Effect and Mechanism of Epigallocatechin Gallate on the Differentiation of 3T3-L1 Preadipocytes.

Green tea possesses a range of beneficial effects, including anti-obesity, antioxidant, and anti-inflammatory properties, owing to its biologically active components, primarily catechins such as epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC), and epigallocatechin gallate (EGCG). However, few studies have investigated the four catechin monomers simultaneously, and the molecular mechanisms of their anti-obesity effects have not been fully elucidated. In this study, we investigated the effects of four catechin monomers on the differentiation of 3T3-L1 preadipocytes of mice. Our findings demonstrated that four catechin monomers EC/ECG/EGC/EGCG (12, 25, 50 µM) dose-dependently inhibited the differentiation of 3T3-L1 preadipocytes and reduced triglyceride content. EGCG exhibited the most potent inhibitory effect with an optimal concentration of 50 µM. In addition, transcriptome sequencing and lipidomic analysis of EGCG-treated 3T3-L1 preadipocytes revealed that Ptgs2 and Pim1 were the most differentially expressed genes involved in regulating adipocyte differentiation. The results suggested that EGCG up-regulated the expression of the Pla2g2e gene and down-regulated the expression of the Pla2g4a and Pla2g2a genes via the glycerophospholipid metabolic pathway, which subsequently elevated lysophosphatidylcholine (LPC) levels, influencing the differentiation process of 3T3-L1 preadipocytes.