Sphingolipid Metabolism Research Articles

Investigating the mechanisms of resveratrol in the treatment of gouty arthritis through the integration of network pharmacology and metabolics.

This study integrates network pharmacology and metabolomics techniques to explore the potential regulatory mechanisms of Res on gouty arthritis (GA). Network pharmacology was used to predict the mechanism of Res in regulating GA, and methods such as HE staining, ELISA, immunohistochemistry, Real-time PCR, Western blot, and molecular docking were used to verify the role of NF-κB, MAPK, and JAK/STAT inflammatory signaling pathways in the MSU-induced GA rat model. In addition, non-targeted metabolomics techniques were combined to further investigate the mechanism of Res in treating GA. The results of network pharmacology showed that Res may exert its therapeutic effects through the NF-κB signaling pathway. Animal experiments demonstrated that in the MSU-induced GA rat model, pathological damage, serum biochemical indicators, and levels of inflammatory factors were significantly increased, and the NF-κB signaling pathway was activated. The intervention of Res significantly reduced pathological damage, serum biochemical indicators, levels of inflammatory factors, and the activation of NF-κB, MAPK, and JAK/STAT signaling pathways in the model rats. Metabolomics results showed that Res could improve the metabolic trajectory deviations in serum and joint fluid of GA model rats. Through related metabolic pathway analysis, the most affected metabolic pathways were found to be Sphingolipid metabolism, Glycerophospholipid metabolism, Phenylalanine, tyrosine and tryptophan biosynthesis, Pantothenate and CoA, Citrate cycle (TCA cycle), and Arachidonic acid metabolism. Resveratrol can regulate the biosynthetic pathways of arachidonic acid, phenylalanine, tyrosine, and tryptophan, pantothenic acid and CoA biosynthesis pathways, TCA cycle, and other metabolic pathways, thereby regulating the NF-κB, MAPK, and JAK/STAT3 signaling pathways, and inhibiting the acute inflammatory response during GA attacks, showing characteristics of multi-pathway and multi-target action.

A systematic evaluation of quenching, extraction and analysis procedures for metabolomics study of the mechanism of QYSLD intervention in A549 cells.

The preparation of cellular metabolomics samples and how to achieve comprehensive coverage of different polar metabolites in cell samples in the analysis pose a challenge for cellular metabolomics. In this study, we optimized a metabolomics protocol based on ultra-high-performance liquid chromatography high-resolution mass spectrometry (UPLC/HRMS) for theextraction and detection of metabolites in A549 cells and exploration of the intervention effect of Qi-Yu-San-Long decoction (QYSLD) on A549 cells. The results indicate that the lowest level of ATP leakage was observed when A549 cells were quenched under liquid nitrogen. MeOH/chloroform/H2O (1:2:1) extraction yielded more chromatographic peaks and excellent reproducibility, and the relative extraction efficiency of most target metabolites was also high. And we optimized thechromatographic separation conditions in both HILIC and RPLC modes, enabling comprehensive detection and analysis of metabolites with varying polarities. Then, we applied the optimized method to UPLC-Q-TOF/MS-based metabolomics of A549 cells to study the mechanism of QYSLD intervention in non-small cell lung cancer (NSCLC). The CCK-8, EdU staining, and cell cycle assay showed that QYSLD inhibited the proliferation of A549 cells by interfering with the cell cycle and blocking them in theG1 phase. A total of 36 differential metabolites associated with the antitumor effects of QYSLD on NSCLC were identified, mainly involving nicotinate and nicotinamide metabolism, sphingolipid metabolism, and glycerophospholipid metabolism. And western blotting confirmed that thechange in 1-methylnicotinamide levels after QYSLD intervention was associated with theinhibition of nicotinamide N-methyltransferase expression in A549 cells.

Targeting an altered sphingolipid profile with consecutive lipotoxicity as therapeutic approach to calcific aortic valve disease

Abstract Background Aortic stenosis due to calcific aortic valve disease (CAVD) is the most common valvular heart disease. In symptomatic patients, without repair the prognosis is poor. Treatment to date is based on surgery or catheter-based interventions. Pharmacological therapy options to prevent the progression of valve calcification are not available. In vascular smooth muscle cells, cellular accumulation of sphingolipids is associated with a proinflammatory response in the sense of lipotoxicity. Chronic inflammatory processes are indeed also essential for aortic valve calcification. Purpose With the subsequent goal of developing innovative treatment approaches for CAVD, we therefore aim to elucidate the unclear role of sphingolipids in the development of CAVD. Methods Human aortic valve and plasma samples of CAVD patients and controls (n=26) were analysed by liquid chromatography–mass spectrometry for lipidomics and proteomics. Human aortic valve interstitial cells (hVICs) were stimulated with ceramides. Calcification was detected by alizarin red staining. mRNA expression of bone-related proteins was determined by qPCR. NF-kB pathway was assessed by proteome profiler. Myriocin and GW4869 were applied to inhibit ceramide biosynthesis. PDTC and MCC950 were used to inhibit NF-kB Pathway and NLRP3 activation. ApoE-/- mice received a gain-of-function PCSK9 adeno-associated virus vector and fed high cholesterol diet for 14 weeks. Myriocin was applied orally over the treatment period to inhibit ceramide de novo synthesis in vivo. Murine echocardiography was used to measure transvalvular velocity and left ventricular function. Calcification degree of murine aortic valve was determined by histological staining. Results A significantly altered sphingolipid profile was observed in aortic valve tissue of CAVD patients (Fig. 1). Ceramide species e.g. Cer (17:1;2O/16:0) were increased. Verifying the biological relevance of these findings in vitro, C2-Cer (d18:1/2:0) enhanced hVIC calcification (Fig. 2). Accordingly, ALP activity and mRNA expression of osteogenic genes RUNX2, ALPL and MSX2 were increased. Furthermore, C2-Cer (d18:1/2:0) enhanced NF-kB p65 phosphorylation and NLRP3 activation, while treatment with both PDTC and MCC950 protected against C2-Cer (d18:1/2:0) induced calcification. Supporting the role of sphingolipid biosynthesis in hVIC calcification, Myriocin and GW4869 both reduced ox-LDL-induced VIC calcification which was reversed by C2-Cer(d18:1/2:0). Finally, Myriocin reduced the degree of calcification and transvalvular jet velocity of aortic valve in the PCSK9-AAV ApoE-/- mice model. Conclusion CAVD is accompanied by an accumulation of ceramides causing lipotoxicity in human aortic valve tissue. Pharmacological modulation of sphingolipid metabolism is an effective approach to prevent the development and progression of aortic valve calcification in vivo and should be considered as a future therapeutic strategy in CAVD patients.Volcano Plot of CAVD tissue lipidomicsC2 Ceramide enhances hVIC calcification

Evidence of honey-processed Astragalus polysaccharides improving intestinal immune function in spleen Qi deficiency mice integrated with microbiomics and metabolomics analysis.

Radix Astragali, commonly known as Astragalus, is a traditional medicinal and edible plant valued for its Qi-tonifying properties. The dosage form of Radix Astragali processed with honey, known as honey-processed Astragalus (HPA), shows improved Qi-tonifying efficacy as compared to the raw product. Polysaccharides are the main bioactive ingredients in its aqueous extract. This study used a multiomics approach integrating microbiomics and metabolomics to elucidate the Qi-tonifying mechanisms of honey-processed Astragalus polysaccharides (HAPS). HAPS-treated mice showed improved symptom scores, spleen and thymus indices, serum cytokines (tumor necrosis factor α, interleukin 1β) and intestinal mucosa secretory immunoglobulin A (SIgA) compared to the mice with spleen Qi deficiency. The analysis of gut microbiota indicated that HAPS regulated the relative abundance of Bacteroidetes, Bacteroides, Proteobacteria and Helicobacter, thereby improving intestinal flora dysbiosis in mice with spleen Qi deficiency. Eleven biomarkers in fecal metabolomics analysis were screened and identified, primarily associated with linoleic acid metabolism, sphingolipid metabolism, glycerophospholipid metabolism and biosynthesis of unsaturated fatty acids. Furthermore, comprehensive analyses demonstrated that HAPS regulates palmitic acid and sphingolipid metabolism by modulating the abundance of Bacteroidetes, which in turn increased the levels of intestinal mucosal SIgA and restored intestinal mucosal immune function in mice with spleen Qi deficiency. Our findings revealed that HAPS is an essential active ingredient of HPA, and its Qi-tonifying mechanism is closely related to the improvement of intestinal immune function. These findings lay the foundation for the application of HAPS as an immunomodulatory agent in health and dietary foods. © 2024 Society of Chemical Industry.

Optical control of sphingolipid biosynthesis using photoswitchable sphingosines.

Sphingolipid metabolism comprises a complex interconnected web of enzymes, metabolites and modes of regulation that influence a wide range of cellular and physiological processes. Deciphering the biological relevance of this network is challenging as numerous intermediates of sphingolipid metabolism are short-lived molecules with often opposing biological activities. Here, we introduce clickable, azobenzene-containing sphingosines, termed caSph s, as light-sensitive substrates for sphingolipid biosynthesis. Photo-isomerization of the azobenzene moiety enables reversible switching between a straight trans - and curved cis -form of the lipid's hydrocarbon tail. Combining in vitro enzyme assays with metabolic labeling studies, we demonstrate that trans -to- cis isomerization of caSph s profoundly stimulates their metabolic conversion by ceramide synthases and downstream sphingomyelin synthases. These light-induced changes in sphingolipid production rates are acute, reversible, and can be implemented with great efficiency in living cells. Our findings establish caSph s as versatile tools with unprecedented opportunities to manipulate sphingolipid biosynthesis and function with the spatiotemporal precision of light.

Effects of ethanol extract from senna leaf (EESL) on inflammation and oxidative stress in mice: A non-targeted metabolomic study.

Senna leaf is a commonly used medication for treating constipation, and long-term use can cause damage to the intestinal mucosa and lead to drug dependence. But the exact mechanism remains unclear. Using non-targeted metabolomics technology to study the mechanism of senna leaf ethanol extract (EESL) inducing inflammation and oxidative stress in mice and causing side effects. EESL was administered to mice by gavage to detect inflammation and oxidative stressrelated factors in mice, and the EESL components and differential metabolites in mouse plasma were analyzed using non-targeted metabolome techniques. 23 anthraquinone compounds were identified in the EESL, including sennoside and their derivatives. Administration of EESL to mice resulted in a significant increase in pro-inflammatory factors, IL-1β, and IL-6 in the plasma, while the levels of IgA significantly decreased. The levels of oxidative stress significantly increased, and the intestinal mucosal integrity was impaired. 21 endogenous in plasma metabolites were identified as differential metabolites related with taurine and taurine metabolism, glycerophospholipid metabolism, arachidonic acid metabolism, tryptophan metabolism, and sphingolipid metabolism. These metabolic pathways are related to oxidative stress and inflammation. Senna leaf can inhibit the expression of tight junction proteins in the intestinal mucosa and disrupt intestinal mucosal barrier integrity, exacerbating oxidative stress and inflammation induced by bacterial LPS entering the bloodstream. In addition, the impact of Senna leaf on tryptophan metabolism may be linked to the occurrence of drug dependence.

Structure Revision of Halisphingosine A via Total Synthesis and Bioactivity Studies.

Sphingoid bases are important bioactive lipids found in a variety of organisms, serving as the backbone of sphingolipids, which regulate essential physiological processes. Here we describe the total synthesis and structure revision of halisphingosine A, a sphingoid base initially isolated from marine sponges. To address inconsistencies in the NMR interpretation of this natural product, we developed a synthetic route involving a late-stage enantioselective Henry reaction that allows access to multiple stereoisomers of the proposed halisphingosine core structure. Our library of 32 fully characterized synthetic stereoisomers enabled us to rectify the structure of halisphingosine A as (2R,3R,8R,Z)-2-aminooctadec-9-ene-1,3,8-triol, and to pursue further structure-activity relation (SAR) studies regarding their antimicrobial and cytotoxic potential. In summary, our study offers a yet unreported compound library along with validated analytical datasets of marine sphingoid base derivatives, which significantly affects future ecometabolomic marine research and will facilitate the identification of inhibitors of sphingolipid metabolism or antagonists of sphingolipid base-sensing receptors.

Sphingosine phosphate lyase insufficiency syndrome as a primary immunodeficiency state

Sphingosine phosphate lyase insufficiency syndrome (SPLIS) is a genetic disease associated with renal, endocrine, neurological, skin and immune defects. SPLIS is caused by inactivating mutations in SGPL1, which encodes sphingosine phosphate lyase (SPL). SPL catalyzes the irreversible degradation of the bioactive sphingolipid sphingosine-1-phosphate (S1P), a key regulator of lymphocyte egress. The SPL reaction represents the only exit point of sphingolipid metabolism, and SPL insufficiency causes widespread sphingolipid derangements that could additionally contribute to immunodeficiency. Herein, we review SPLIS, the sphingolipid metabolic pathway, and various roles sphingolipids play in immunity. We then explore SPLIS-related immunodeficiency by analyzing data available in the published literature supplemented by medical record reviews in ten SPLIS children. We found 93% of evaluable SPLIS patients had documented evidence of immunodeficiency. Many of the remainder of cases were unevaluable due to lack of available immunological data. Most commonly, SPLIS patients exhibited lymphopenia and T cell-specific lymphopenia, consistent with the established role of the S1P/S1P1/SPL axis in lymphocyte egress. However, low B and NK cell counts, hypogammaglobulinemia, and opportunistic infections with bacterial, viral and fungal pathogens were observed. Diminished responses to childhood vaccinations were less frequently observed. Screening blood tests quantifying recent thymic emigrants identified some lymphopenic SPLIS patients in the newborn period. Lymphopenia has been reported to improve after cofactor supplementation in some SPLIS patients, indicating upregulation of SPL activity. A variety of treatments including immunoglobulin replacement, prophylactic antimicrobials and special preparation of blood products prior to transfusion have been employed in SPLIS. The diverse immune consequences in SPLIS patients suggest that aberrant S1P signaling may not fully explain the extent of immunodeficiency. Further study will be required to fully elucidate the complex mechanisms underlying SPLIS immunodeficiency and determine the most effective prophylaxis against infection.

Serum metabolic profile evidence for relationship between schizophrenia and depression: An untargeted metabolomics.

Given the genetic and clinical overlap observed between schizophrenia and depression, the present study was to identify the similarities and differences in serum metabolic profiles between patients with schizophrenia and depression. Global metabolomics research methods based on UHPLC-QTOF-MS/MS were performed. A total of 113 and 118 differential metabolites were screened and identified in depression and schizophrenia groups, respectively, as compared to health control; among those, 94 differential metabolites were shared by both. Pathway analysis indicated arginine and proline metabolism, alanine, aspartate, and glutamate metabolism were two significant metabolic pathways both in depression and schizophrenia groups as compared with health control groups, respectively. Similarly, 77 differential metabolites were identified between depression and schizophrenia groups, in which, serum N-acetylglutamine and isovalerylglycine levels showed significant differences between patients with depression and schizophrenia with p values less than 0.001 and without significant outliers. Sphingolipid metabolism was identified as a significant metabolic pathway distinguishing between depression and schizophrenia groups based on pathway analysis. Conclusively, common alterations in arginine and proline metabolism, alanine, aspartate, and glutamate metabolism were observed in patients with schizophrenia and depression; whereas differences in serum N-acetylglutamine and isovalerylglycine levels as well as sphingolipid metabolism were discovered between the two categories of patients.

Unveiling the Metabolomic Profile of Oily Sensitive Skin: A Non-Invasive Approach

Skin barrier impairment is becoming increasingly common due to changes in lifestyle and modern living environments. Oily sensitive skin (OSS) is a condition that is characterized by an impaired skin barrier. Thus, examining the differences between OSS and healthy skin will enable a more objective evaluation of the characteristics of OSS and facilitate investigations of potential treatments. Initially, a self-assessment questionnaire was used to identify patients with OSS. Biophysical measurements and LAST scores were used to determine whether skin barrier function was impaired. Epidermal biophysical properties, including skin hydration, transepidermal water loss (TEWL), sebum content, erythema index (EI), and a* value, were measured with noninvasive instruments. We subsequently devised a noninvasive D-square sampling technique to identify changes in the skin metabolome in conjunction with an untargeted metabolomics analysis with an Orbitrap Q ExactiveTM series mass spectrometer. In the stratum corneum of 47 subjects, 516 skin metabolites were identified. In subjects with OSS, there was an increase in the abundance of 15 metabolites and a decrease in the abundance of 48 metabolites. The participants with OSS were found to have the greatest disruptions in sphingolipid and amino acid metabolism. The results revealed that an impaired skin barrier is present in patients with OSS and offers a molecular target for screening for skin barrier damage.

Metabolomic changes in preterminal serum samples of rhesus macaques exposed to two different lethal doses of total-body gamma-radiation

Exposure to ionizing radiation induces cellular and molecular damage leading to a cascade of events resulting in tissue and organ injury. Our study strives to characterize and validate metabolomic changes in preterminal stage (immediately prior to death) samples collected from rhesus macaques lethally irradiated with one of two different doses of radiation. Peripheral blood samples were collected pre-exposure, post-exposure, and at the preterminal stage of nonhuman primates (NHPs that did not survive exposure with 7.2 Gy or 7.6 Gy total-body radiation (LD60-80/60)). We analyzed global metabolomic alterations using ultra-performance liquid chromatography (UPLC) quadrupole time-of-flight mass spectrometry (QTOF-MS) in serum samples collected at various timepoints in relation to radiation exposure. The goal of this study was to validate the metabolic shifts present in samples collected just prior to death, which were reported earlier in a preliminary study with a limited number of samples and a single dose of radiation. Here, we demonstrate that radiation exposure induced significant time-dependent metabolic alterations compared with pre-exposure samples. We observed significant metabolite dysregulation in animals exposed to 7.6 Gy compared to 7.2 Gy. Greater metabolic disruption was observed in the preterminal groups than all of the other post-irradiation timepoints in both cohorts. Metabolomic shifts in these preterminal groups also revealed consistent disturbances in sphingolipid metabolism, steroid hormone biosynthesis, and glycerophospholipid metabolism pathways. Overall, the sphingolipid metabolism pathway appears to be representative of the preterminal phenotype, confirming the results of our preliminary study. These results offer important and novel insights for identification and validation of biomarkers for lethality, and such observations would be valuable for triage during a radiological/nuclear mass casualty scenario.

Exposure to PFOA, PFOS, and PFHxS induces Alzheimer's disease-like neuropathology in cerebral organoids

Per- and polyfluoroalkyl substances (PFASs), a class of ubiquitous synthetic organic chemicals, are widely utilized across various industrial applications. However, the long-term neurological health effects of PFAS mixture exposure in humans remain poorly understood. To address this gap, we have designed a comprehensive study to predict and validate cell-type-specific neurotoxicity of PFASs using single-cell RNA sequencing (scRNA-seq) and cerebral organoids. Cerebral organoids were exposed to a PFAS mixture at concentrations of 1 × (10 ng/ml PFOS and PFOA, and 1 ng/ml PFHxS), 30 × , and 900 × over 35 days, with a follow-up analysis at day 70. Pathological alterations and lipidomic profiles were analyzed to identify disrupted molecular pathways and mechanisms. The scRNA-seq data revealed a significant impact of PFASs on neurons, suggesting a potential role in Alzheimer's Disease (AD) pathology, as well as intellectual and cognitive impairments. PFAS-treated cerebral organoids exhibited Aβ accumulation and tau phosphorylation. Lipidomic analyses further revealed lipid disturbances in response to PFAS mixture exposure, linking PFAS-induced AD-like neuropathology to sphingolipid metabolism disruption. Collectively, our findings provide novel insights into the PFAS-induced neurotoxicity, highlighting the significance of sphingolipid metabolism in the development of AD-like neuropathology. The use of cerebral organoids and scRNA-seq offers a powerful methodology for evaluating the health risks associated with environmental contaminants, particularly those with neurotoxic potential.

Oral Disease and Atherosclerosis May Be Associated with Overlapping Metabolic Pathways.

Dental caries and periodontitis are among the most prevalent chronic diseases worldwide and have been associated with atherosclerotic cardiovascular diseases (ASCVD). This study aimed to determine (1) the independent associations between subclinical ASCVD markers (carotid intima media thickness [CIMT] and coronary artery calcification [CAC]) and quantitative indices of oral disease including the decayed, missing, and filled teeth (DMFT) index, gingivitis parameters, periodontal status, and number of teeth lost and (2) the extent to which metabolites altered in individuals with oral disease overlapped with those altered in individuals with ASCVD. We used data from 552 participants recruited through the Dental Strategies Concentrating on Risk Evaluation project. Oral examinations were conducted, and CIMT and CAC were measured. Multiple linear regression models were constructed with CIMT and CAC as dependent variables in the epidemiologic analysis. In the metabolomic analysis, logistic or linear regression was used to test 1,228 metabolites for association with each phenotype adjusted for age, sex, race, blood pressure, smoking, diabetes, cholesterol, high-sensitivity C-reactive protein, and interleukin-6. None of the oral disease markers were significant predictors of ASCVD markers in the fully adjusted models. However, critical lipid and lipid-signaling pathway metabolites were significantly associated with gingivitis, periodontitis, and DMFT: the lysophospholipid pathway (odds ratio [OR] = 2.29, false discovery rate [FDR]-adjusted P = 0.038) and arachidonate with gingivitis (OR = 2.35, FDR-adjusted P = 0.015), the sphingolipid metabolism pathway with periodontitis (OR = 2.09, FDR-adjusted P = 0.029), and borderline associations between plasmalogen and lysophospholipid pathways and DMFT (P = 0.055). Further, the same metabolite from the sphingolipid metabolism pathway, sphingomyelin (d17:1/14:0, d16:1/15:0), was inversely associated with both CIMT (β = -0.14, FDR-adjusted P = 0.014) and gingivitis (OR = 0.04, FDR-adjusted P = 0.033). The discovery of a common sphingomyelin metabolite in both disease processes is a novel finding suggesting that gingivitis and periodontitis may be associated with some overlapping metabolic pathways associated with ASCVD and indicating potential shared mechanisms among these diseases. The same metabolites may be altered in atherosclerosis and oral disease. Specifically, a common sphingomyelin metabolite was inversely associated with gingivitis and carotid intima media thickness, a subclinical marker of atherosclerotic cardiovascular disease. These findings can provide valuable insights for future mechanistic studies to establish potential causal relationships, with the hope of influencing disease prevention and targeted early treatment.

Integrated lipidomic and transcriptomics to explore the effects of ethyl acetate extract of Herpetospermum pedunculosum on nonalcoholic fatty liver disease in mice

Ethnopharmacological relevanceHerpetospermum pedunculosum (Ser.) C.B. Clarke (HP), a traditional Tibetan medicine used to treat hepatobiliary diseases, was confirmed that lignans-enriched ethyl acetate extract of HP (EAHP) could alleviate the hepatic injury by modern pharmacological evidence. However, the effects and potential mechanisms of EAHP against nonalcoholic fatty liver disease (NAFLD) are still unknown. Aim of the studyTo reveal the effects of EAHP on NAFLD and explore the potential mechanisms from the perspective of lipidomics and transcriptomics. Materials and methodsUPLC‒Q–TOF‒MS analysis was carried out to investigate the chemical components of EAHP. A Choline-deficient, L-amino acid defined, high fat diet (CDAHFD) was used to establish a NAFLD mouse model. The anti-NAFLD effects of various dosages of EAHP were evaluated by biochemical indexes and histological analysis. Hepatic lipidomic and transcriptomic analysis and multiple bioinformatics methods were used to screen biomarkers and signaling pathways. The levels of the corresponding genes were verified by qPCR. Results36 kinds of compounds were identified by UPLC‒Q–TOF‒MS analysis. Oral treatment with EAHP significantly decrease the liver index and the levels of ALT and AST in the serum. The measurements lipid content and Oil Red O staining results suggested that EAHP ameliorated lipid metabolism disorders by reducing the content of TG and LDL-C, increasing HDL-C in the liver. H&E staining and ELISA revealed that EAHP restored hepatic inflammatory infiltration and decrease the levels of IL-1β, IL-6, TNF-α, and increase IL-10 in the serum. Lipidomic analysis showed that EAHP could regulate CDAHFD-induced lipid metabolic disorder. The different lipid metabolites included TG, phosphatidyl choline (PC), diacylglycerol (DG), phosphatidylethanolamine (PE), phosphatidylinositol (PI), ceramide (Cer). Transcriptomic analysis revealed that Bmp8b, Nbl1, Rgma, Sphk1, Thbs1, and Ugt8a were important regulators, which were associated with TGF-β signaling pathway and sphingolipid metabolism. The expressions of above genes detected by were qPCR consistent with transcriptomic data. ConclusionsThe ameliorative effects of EAHP on NAFLD are potentially attributable to the regulation of sphingolipid metabolism and TGF-β signaling pathway, etc., which results in abnormal hepatic lipid metabolism and inflammatory response.

Sphingolipid Analysis in Clinical Research.

Sphingolipids are the most diverse class of lipids due to the numerous variations in their structural components. This diversity is also reflected in their extremely different functions. Sphingolipids are not only constituents of cell membranes but have emerged as key signaling molecules involved in a variety of cellular functions, such as cell growth and differentiation, proliferation and apoptotic cell death. Lipidomic analyses in clinical research have identified pathways and products of sphingolipid metabolism that are altered in several human pathologies. In this article, we describe how to properly design a lipidomic experiment in clinical research, how to handle plasma and serum samples for this purpose, and how to measure sphingolipids using liquid chromatography-mass spectrometry.

Blockade of TREM2 ameliorates pulmonary inflammation and fibrosis by modulating sphingolipid metabolism

Pulmonary fibrosis is a chronic interstitial lung disease involving systemic inflammation and abnormal collagen deposition. Dysregulations in lipid metabolism, such as macrophage-dependent lipid catabolism, have been recognized as critical factors for the development of pulmonary fibrosis. However, little is known about the signaling pathways involved and the key regulators. Here we found that triggering receptor expressed on myeloid cells 2 (TREM2) plays a pivotal role in regulating the lipid handling capacities of pulmonary macrophages and triggering fibrosis. By integrating analysis of single-cell and bulk RNA sequencing data from patients and mice with pulmonary fibrosis, we revealed that pulmonary macrophages consist of heterogeneous populations with distinct pro-fibrotic properties, and found that both sphingolipid metabolism and the expression of chemotaxis-related genes are elevated in fibrotic lungs. TREM2, a sensor recognizing multiple lipid species, is specifically upregulated in a subset of monocyte-derived macrophages. Blockade of TREM2 by conventional/conditional knock-out or soluble TREM2 administration can attenuate bleomycin-induced pulmonary fibrosis. By utilizing scRNA Seq and lipidomics, we found that Trem2 deficiency downregulates the synthesis of various sphingomyelins, and inhibits the expression of chemokines such as Ccl2. Together, our findings not only reveal the alterations in lipidomic profiles and the atlas of pulmonary macrophages during pulmonary fibrosis, but also suggest that targeting TREM2, the crucial regulator affecting both pulmonary sphingolipid metabolism and the chemokines secretion, can benefit pulmonary fibrosis patients in the future.

Sphingosine Kinase 2 Controls the Aggressive Phenotype of Oral Squamous Cell Carcinoma by Regulating miR-205 and miR-296 through p53

Alterations in microRNAs, p53, and sphingolipid metabolism have been associated with head and neck squamous cell carcinoma (HNSCC). However, sphingosine kinase 2, a critical enzyme in sphingolipid metabolism, is poorly understood in HNSCC. Our aim was to investigate how SK2 and p53 interact to regulate miR-205 and miR-296. Analysis of small-RNA-seq data from non-tumor oral keratinocytes with SK2 overexpression (NOK-SK2) compared to NOK-control (NOK- Ø) revealed differential expression of more than 100 miRNAs being half regulated by p53. The expression of miR-205 was downregulated, and miR-296 was upregulated in NOK-SK2 cells; however, cells with SK2 knockdown and p53 overexpression showed an opposite profile. Proteins involved in miRNA biogenesis were increased in NOK-SK2 cells while their levels were decreased in NOK-SK2 cells with p53 overexpression. miR-205 mimic and miR-296 inhibitor decreased the aggressiveness and cancer stem-like cells in oral keratinocytes and oral carcinoma cells with SK2 deregulation. Overexpression of miR-205 in HN12-SK2 cells decreased tumor formation capacity and NOK-SK2 cells abrogated the tumor growth in mice. Our results indicate crosstalk between SK2 and p53 in regulating miR-205 and miR-296, which could be potential targets for HNSCC therapy.

Mechanism of Panax notoginseng saponins in improving cognitive impairment induced by chronic sleep deprivation based on the integrative analysis of serum metabolomics and network pharmacology

Panax notoginseng saponin (PNS) has a variety of biological activities, such as improvement of myocardial ischemia, improvement of learning and memory, hypolipidemia, and immunomodulation. However, its protective mechanism on the central nervous system (CNS) is not clear. The present study initially evaluated the possible mechanism of PNS to improve cognitive dysfunction due to chronic sleep deprivation (CSD). In the present study, we used a modified multi-platform aquatic environment sleep deprivation method to induce a cognitively impaired rat model, and explored the mechanism of action of PNS by integrating serum metabolomics and network pharmacology, which was further verified by molecular docking and experiments. The results showed that PNS significantly shortened the escape latency, increased the target quadrant time and the number of traversing platforms, and attenuated the inflammatory damage in the hippocampal Cornu Ammonis 1 (CA1) region in CSD rats. The non-targeted metabolomics results indicated that 35 biomarkers significantly altered following PNS therapy intervention, with metabolic pathways enriched for the effects of One carbon pool by folate, Riboflavin metabolism, Glycerophospholipid metabolism, Sphingolipid metabolism, Glycerolipid metabolism, Arachidonic acid metabolism, and Tryptophan metabolism. In addition, network pharmacology identified 234 potential targets for PNS intervention in CSD with cognitive impairment. Metabolite-response-enzyme-gene network was constructed by MetaScape and matched with the network pharmacology results to identify a total of five shared targets (LPL, GPAM, HSD11B1, HSD11B2, and SULT2A1) and two metabolic pathways (Sphingolipid metabolism and Steroid hormone biosynthesis). The results of molecular docking revealed that the five active ingredients had good binding ability with the five core targets. qPCR analysis confirmed the ability of PNS to modulate the above five targets. The combination of metabolomics and network analysis provides a scientific basis for promoting the clinical application of PNS in cognitive impairment.

Effects of Stress on Biological Characteristics and Metabolism of Periodontal Ligament Stem Cells of Deciduous Teeth

Introduction and AimsPeriodontal ligament stem cells (PDLSCs) from deciduous teeth (DePDLSCs) can perceive and respond to mechanical signals upon exposure to various environments. The effects of mechanical stress on the biological characteristics and metabolism of DePDLSCs were investigated using in vitro stress loading. MethodsDePDLSCs were subjected to mechanical stresses of different strengths. Cell proliferation, expression of osteogenic/osteoclastic factors, apoptosis, and oxidative stress levels were evaluated using CCK-8 assays, alkaline phosphatase staining, real-time PCR, flow cytometry, and malondialdehyde and superoxide dismutase assays. Liquid chromatography-mass spectrometry was used to perform nontargeted metabolomic detection and analysis. ResultsUnder stresses of 75 and 150 kPa, the expression of osteogenesis-related factors OPG, ALP, and RUNX2 decreased, and the ratio of RANKL/OPG significantly increased. A pressure of 150 kPa induced oxidative stress and caused a significant increase in cell apoptosis. Among the differential metabolites screened from the 150 kPa group, spermine, spermidine, ceramide, phosphatidylethanolamine, lysophosphatidylethanolamine, linoleic acid, and docosatrienoic acid were the most significantly upregulated. The metabolites screened from the 75 kPa group were mainly related to glycerophospholipid and sphingolipid metabolism, oxidative phosphorylation, and mineral absorption, which were common pathways affected in both experimental groups. ConclusionA certain degree of mechanical stress can inhibit the proliferative activity and osteogenic differentiation of DePDLSCs, enhance their osteoclast-inducing ability, and cause elevated levels of cell apoptosis and oxidative stress. The metabolic expression profile of DePDLSCs changed significantly under stress. Understanding changes in cellular activity and metabolic reactions may provide an experimental basis for elucidating the role of mechanical stress in root resorption and periodontal tissue remodelling of deciduous teeth. Clinical RelevanceMechanical stress may affect periodontal tissue remodeling and root resorption of DePDLSc.

Metabolomics and lipidomics in pectus excavatum: preliminary screening of biomarkers for early diagnosis.

Pectus excavatum (PE) is the most common chest wall deformity, characterized by an insidious onset, gradual progression, and challenges in early diagnosis. It is often accompanied by emaciation and distinctive metabolic traits, which may provide valuable insights into its internal physiological and biochemical mechanisms. Our study attempted to screen out biomarkers by identifying the metabolic characteristics of PE, and the results provide a scientific basis for the early diagnosis of PE. Untargeted metabolomic and lipidomic analyses using liquid chromatography-mass spectrometry was conducted on serum samples obtained from 20 patients diagnosed with PE and 30 healthy case-controls. Principal component analysis and partial least squares discriminant analysis were employed to assess the quality of the metabolic profiling and delineate the metabolic differences between the PE and healthy cohorts. Receiver operating characteristic analysis was conducted to evaluate the predictive accuracy of the selected biomarkers. Pathway analysis of the dysregulated metabolites was utilized to elucidate the underlying pathological pathways. Fourteen metabolites and seven lipids were found to be differentially expressed between patients with PE and healthy controls. Indole-3-acetaldehyde showed potential as a biomarker for PE, with an area under the curve value of 0.94, making it effective in distinguishing patients with PE. Pathway analysis revealed enrichment of several pathological pathways, such as valine, leucine, and isoleucine biosynthesis; sphingolipid metabolism; glycine, serine, and threonine metabolism; and glycerophospholipid metabolism. In our study, we employed a multiomics approach to comprehensively examine dysregulated serological molecules in PE patients, and the analyses revealed potential biomarkers for early diagnosis and provided information for pathological studies.