Lipid Signaling Research Articles

Associations of the hs-CRP/HDL-C ratio with cardiovascular disease among US adults: evidence from NHANES 2015-2018

Background and AimsInflammation, lipid signaling, and their interplay are involved in the pathogenesis and development of cardiovascular diseases (CVDs), while the relationships of composite indices combining inflammation and lipids with CVD remained inexplicit in the American population. Methods and ResultsOur study enrolled 8,581 adults from the National Health and Nutrition Examination Survey 2015-2018. Logistic regression model was applied to assess the associations of high-sensitivity C-reactive protein (hs-CRP)-to-high-density lipoprotein cholesterol (HDL-C) ratio with CVD prevalence. Potential mediating effects of hypertension, diabetes, hypercholesterolemia, and obesity on significant associations were explored. Receiver operating characteristic (ROC) curves were generated to compare diagnostic values of the hs-CRP/HDL-C ratio, HDL-C, and hs-CRP. Compared with those in the first quartile of the hs-CRP/HDL-C ratio, participants in the fourth quartile presented higher risks of CVD subtypes and total CVD. Each one-unit increment of the hs-CRP/HDL-C ratio was associated with a 25% increase in CVD risk (95% confidence interval: 1.11, 1.41) with significant uptrends across the hs-CRP/HDL-C ratio quartiles. Four metabolic disorders significantly mediated associations of the hs-CRP/HDL-C ratio with CVDs. Younger participants were more sensitive to higher hs-CRP/HDL-C ratio with significant interactions in CVD. ROC curves further illustrated the relatively good diagnostic efficacy of the hs-CRP/HDL-C ratio for CVD. ConclusionThe hs-CRP/HDL-C ratio was a significant risk factor for CVDs among US adults, in which greater prevalence of hypertension, diabetes, hypercholesterolemia, and obesity played important mediating roles. Early attention to people with elevated hs-CRP/HDL-C ratio would be helpful for CVD risk reduction.

Effects of the organochlorine pesticide metabolite p,p’-DDE on the gastrointestinal lipidome in fish: A novel toxicity pathway for a legacy pollutant

Though phased out from use in the United States, environmental contamination by organochlorine pesticides (OCPs) remains a widespread issue, especially around intensive agricultural regions. OCPs, such as dichlorodiphenyltrichloroethane (DDT) and its primary metabolite, dichlorodiphenyldichloroethylene (DDE), have been detected in soils, sediments, surface waters, and biota decades after their discontinued use. As OCPs are persistent and can bioaccumulate in fats, these compounds can transfer and magnify across food webs. Freshwater predatory fish and birds can accumulate high OCP concentrations, leading to a myriad of deleterious impacts on organismal health. Studies have found evidence of reproductive disruption in predatory fish, such as the largemouth bass (LMB; Micropterus salmoides), associated with DDT and DDE exposure. DDE can act through estrogenic pathways and induce the expression of estrogenic signals in male animals; however, the molecular mechanism of disruption is unclear. Recently, metabolomics research has revealed corollary relationships between lipid signals and organic pollutant toxicity. Here, a two-month feeding experiment on LMB was conducted to assess the interactions of DDE (as p,p'-DDE) in food with gut and liver lipid signaling. Targeted lipidomic analysis revealed global alterations in the abundance of tissue lipids, especially cholesteryl esters and phospholipids, in LMB exposed to low levels of p,p'-DDE. Results from these studies indicate that p,p'-DDE may act through disruption of normal lipid homeostasis to cause toxicity in freshwater fish.

Transcriptome signature for multiple biotic and abiotic stress in barley (Hordeum vulgare L.) identifies using machine learning approach

Barley (Hordeum vulgare L.) is exposed to various biotic and abiotic stresses, making it crucial to fully understand the gene signatures that respond to stress. This study utilizes machine learning to analyze transcriptomic data from 515 RNA-seq profiles across 18 independent studies, covering eleven abiotic and three biotic stress types. Through meticulous data preprocessing, including quality assessment and batch effect correction, we have identified 4,311 genes for further analysis. Feature selection was performed using five weighting algorithms, resulting in the prioritization of 400 core genes. Machine learning models, specifically Random Forest and C4.5, were optimized and evaluated using a 10-fold cross-validation approach. The C4.5 algorithm demonstrated superior accuracy in predicting stress-responsive signatures. Key genes, such as bHLH119 and E3 ubiquitin protein ligase DRIP2, were identified as potential biomarkers. Functional enrichment analysis, conducted through protein-protein interaction networks and Gene Ontology/KEGG pathway analysis, has revealed significant involvement in lipid biosynthesis, signal transduction, and defense response processes. These findings highlight the crucial roles of the identified biomarkers genes in barley's resilience to stress and provide potential targets for genetic improvement. Future research should focus on validating these biomarkers in different barley cultivars and under field conditions to enhance crop resilience against stressors.

Characteristics of Gracilariopsis lemaneiformis hydrocolloids and their effects on intestine PPAR signaling and liver lipid metabolism in Oreochromis niloticus: A multiomics analysis

Characteristics of Gracilariopsis lemaneiformis hydrocolloids and their effects on intestine PPAR signaling and liver lipid metabolism in Oreochromis niloticus: A multiomics analysis

Targeting Oxidative Stress and Inflammation in the Eye: Insights from a New Model of Experimental Autoimmune Uveitis

Autoimmune uveitis is a relapsing blind-causing ocular condition with complex pathogenesis that is not completely understood. There is a high demand for accurate animal models of experimental autoimmune uveitis (EAU) suitable for elucidating the molecular mechanisms of the disease and testing new therapeutic approaches. Here, we demonstrated that photoreceptor Ca2+/Zn2+-sensor protein recoverin is a uveoretinal antigen in albino rabbits provoking typical autoimmune chorioretinitis 2–4 weeks after immunization. The pathologic process in recoverin-induced EAU shared features with human disease and included lymphocytic infiltration of the retina, Dalen–Fuchs nodules and foci of subtotal or total retinal atrophy, manifested as a decrease in amplitude of the a-wave of the electroretinogram. In some cases, changes in the retinal vascular pattern and subretinal hemorrhages were also observed. These signs were accompanied by a gradual accumulation of serum antibodies against recoverin. Biochemical examination of the aqueous humor (AH) revealed typical characteristics of inflammation and oxidative stress, including increased levels of TNF-α and IL-6 and decreased levels of IL-10, as well as decreased total antioxidant activity, superoxide dismutase and glutathione peroxidase activities, and increased zinc concentration. Consistently, metabolomic and targeted lipidomic analysis of AH showed high lactate and low ascorbic acid levels in early EAU; increased levels of key pro-inflammatory signaling lipids such as PGE2, TXB2, 11-HETE and Lyso-PAF; and reduced levels of the anti-inflammatory fatty acid DHA in advanced stages of the disease. Uveitic AH became enriched with recoverin, confirming disruption of the blood–ocular barrier and photoreceptor damage. Notably, the application of mitochondria-targeted antioxidant therapy impeded EAU progression by maintaining local antioxidant activity and suppressing TNF-α, IL-6 and PGE2 signaling. Overall, our results demonstrate that recoverin-induced EAU in rabbits represents an accurate model of human autoimmune posterior uveitis and suggest new directions for its therapy that can be trialed using the developed model.

The membrane domains of mammalian adenylyl cyclases are lipid receptors.

The biosynthesis of cyclic 3',5'-adenosine monophosphate (cAMP) by mammalian membrane-bound adenylyl cyclases (mACs) is predominantly regulated by G-protein-coupled receptors (GPCRs). Up to now the two hexahelical transmembrane domains of mACs were considered to fix the enzyme to membranes. Here, we show that the transmembrane domains serve in addition as signal receptors and transmitters of lipid signals that control Gsα-stimulated mAC activities. We identify aliphatic fatty acids and anandamide as receptor ligands of mAC isoforms 1-7 and 9. The ligands enhance (mAC isoforms 2, 3, 7, and 9) or attenuate (isoforms 1, 4, 5, and 6) Gsα-stimulated mAC activities in vitro and in vivo. Substitution of the stimulatory membrane receptor of mAC3 by the inhibitory receptor of mAC5 results in a ligand inhibited mAC5-mAC3 chimera. Thus, we discovered a new class of membrane receptors in which two signaling modalities are at a crossing, direct tonic lipid and indirect phasic GPCR-Gsα signaling regulating the biosynthesis of cAMP.

The Synergy between Topography and Lipid Domains in the Plasma Membrane of Mast Cells Controls the Localization of Signaling Proteins and Facilitates their Coordinated Activation.

Similar to T cells and B cells, mast cell surfaces are dominated by microvilli, and like these other immune cells we showed with microvillar cartography (MC) that key signaling proteins for RBL mast cells localize to these topographical features. Although stabilization of ordered lipid nanodomains around antigen-crosslinked IgE-FcεRI is known to facilitate necessary coupling with Lyn tyrosine kinase to initiate transmembrane signaling in these mast cells, the relationship of ordered-lipid nanodomains to membrane topography had not been determined. With nanoscale resolution provided by MC, SEM and co-localization probability (CP) analysis, we found that FcεRI and Lyn kinase are positioned exclusively on the microvilli of resting mast cells in separate nano-assemblies, and upon antigen-activation they merge into overlapping populations together with the LAT scaffold protein, accompanied by elongation and merger of microvilli into ridge-like ruffles. With selective lipid probes, we further found that ordered-lipid nanodomains preferentially occupy microvillar membranes, contrasting with localization of disordered lipids to flatter regions. With this proximity of signaling proteins and ordered lipid nanodomains in microvilli, the mast cells are poised to respond sensitively and efficiently to antigen but only in the presence of this stimulus. Use of a short chain ceramide to disrupt ordered-lipid regions of the plasma membrane and evaluation with MC, CP, and flow cytometry provided strong evidence that the microvillar selective localization of signaling proteins and lipid environments is facilitated by the interplay between ordered-lipid nanodomains and actin attachment proteins, ERM (ezrin, radixin, moesin) and cofilin.

The Impact of a Ketogenic Diet on Late-Stage Pancreatic Carcinogenesis in Mice: Efficacy and Safety Studies.

High-fat diets (HFDs) have been associated with an increased risk of pancreatic cancer. In contrast, ketogenic diets (KDs) have been shown to display anti-tumor characteristics. The objective of this work was to evaluate the efficacy of a KD on late-stage pancreatic carcinogenesis in a genetically modified mouse model of pancreatic cancer [LSL-KrasG12D/+; Ptf1-Cre (KC) mice], as well as its liver safety, and to compare it to that of an HFD. Six-month-old female and male KC mice were randomly allocated to either a control diet (CD) (%kcal: 20% fat, 15% protein, 65% carbohydrates), an HFD (%kcal: 40% fat, 15% protein, 45% carbohydrate) or a KD (%kcal: 84% fat, 15% protein, 1% carbohydrate) and fed these diets for 6 months. HFD-fed, but not KD-fed, mice showed a 15% increase in body weight, plus elevated serum insulin (2.4-fold increase) and leptin (2.9-fold increase) levels, compared to CD-fed mice. At the pancreas level, no differences in pancreatic cancer incidence rates were observed among the diet groups. Regarding the liver safety profile, the HFD-fed mice had higher serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP), when compared to the CD and KD groups. In addition, upon histologic examination, an HFD, but not a KD, showed a ~2-fold increase in both macro- and microsteatosis, as well as 35% and 32% higher levels of TLR4 and NF-κB activation, respectively, compared to CD-fed mice. In summary, although a KD intervention alone did not prevent pancreatic carcinogenesis, our data suggests that a KD modulates insulin signaling and hepatic lipid metabolism, highlighting its beneficial effects on healthspan and liver function when compared to an HFD.

Scavenger Receptor CD36 in Tumor-Associated Macrophages Promotes Cancer Progression by Dampening Type I Interferon Signaling.

Tumor-associated macrophages (TAMs) are a heterogenous population of myeloid cells that dictate the inflammatory tone of the tumor microenvironment (TME). In this study, we unveiled a mechanism by which scavenger receptor CD36 suppresses TAM inflammatory states. CD36 was upregulated in TAMs and associated with immunosuppressive features, and myeloid-specific deletion of CD36 significantly reduced tumor growth. Moreover, CD36-deficient TAMs acquired inflammatory signatures including elevated type-I interferon (IFN-I) production, mirroring the inverse correlation between CD36 and IFN-I response observed in cancer patients. IFN-I, especially IFNβ, produced by CD36-deficient TAMs directly induced tumor cell quiescence and delayed tumor growth. Mechanistically, CD36 acted as a natural suppressor of IFN-I signaling in macrophages through p38 activation downstream of oxidized lipid signaling. These findings establish CD36 as a critical regulator of TAM function and the tumor inflammatory microenvironment, providing additional rationale for pharmacological inhibition of CD36 to rejuvenate anti-tumor immunity.

Aramchol attenuates fibrosis in mouse models of biliary fibrosis and blocks the TGFβ-induced fibroinflammatory mediators in cholangiocytes.

Fibroinflammatory cholangiopathies, such as primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC), are characterized by inflammation and biliary fibrosis, driving disease-related complications. In biliary fibrosis, cholangiocytes activated by transforming growth factor-β (TGFβ) release signals that recruit immune cells to drive inflammation and activate hepatic myofibroblasts to deposit the extracellular matrix (ECM). TGFβ regulates stearoyl-CoA desaturase (SCD), an enzyme that catalyzes the synthesis of monounsaturated fatty acids, in stimulating fibroinflammatory lipid signaling. However, the role of SCD or its inhibitor, Aramchol, has not been investigated in biliary fibrosis or TGFβ-mediated cholangiocyte activation. 10-16-week-old multi-drug resistance 2 knockout (Mdr2 -/- ) and 3,5-diethoxycarboncyl-1,4-dihydrocollidine (DDC) diet-fed mice were orally gavaged daily with Aramchol at 12.5 mg/kg/day for 4 and 3 weeks, respectively. Liver and serum were harvested for the assessment of fibrosis and inflammation. Transformed human cholangiocyte cells (H69) and mouse large biliary epithelial cells (MLEs) were used to test the effects of the SCD inhibitor, Aramchol, at varying doses on TGFβ-mediated expression of fibroinflammatory signals and were confirmed in PSC-derived cholangiocytes (PSC-Cs) using ELISA, qPCR, and Western blot analyses. Aramchol treatment of Mdr2 -/- mice with established biliary fibrosis (treatment) and DDC diet-induced (prevention) models of cholestatic injury and fibrosis demonstrated significant reductions in both measures of ECM synthesis (mRNA expression of ECM components in the liver), collagen content of the liver (picrosirius red staining and hydroxyproline content) and myofibroblast activation (αSMA staining). Il6 and Tnfa were also reduced with Aramchol in the liver. RNA-seq analysis of H69 cells showed that Aramchol co-treatment led to significant inhibition of TGFβ-induced hepatic fibrosis pathways while upregulating peroxisome proliferator-activated receptor (PPAR) signaling. SCD expression was significantly increased in TGFβ-treated H69 cells (2-fold, p<0.05). Aramchol in a dose-dependent manner significantly attenuated the increased expression of the fibrotic marker, plasminogen activator inhibitor-1 (PAI-1/SERPINE1), and hepatic stellate cell-activating genes ( VEGFA and PDGFB ) in TGFβ-activated H69 and MLEs. Aramchol also markedly reduced the expression of the inflammatory cytokine, interleukin 6 (IL6). SCD siRNA knockdown produced similar results in H69 cells. Furthermore, in PSC-Cs, the expressions of SCD, VEGFA and IL6 were significantly reduced with Aramchol. The expression of the anti-fibroinflammatory factors PPARα and -γ were modestly increased in cholangiocyte cell lines with increased expression of PPAR-responsive genes and increased nuclear binding of DNA PPAR response elements with Aramchol co-treatment compared to TGFβ only. Aramchol, an SCD inhibitor, both attenuates and prevents biliary fibrosis in mouse models of cholestatic injury and fibrosis. This effect is partially due to Aramchol inhibiting TGFβ-induced fibroinflammatory mediators in cholangiocytes by upregulating PPARα and -γ expression and activity. These findings, along with Aramchol's excellent safety profile in clinical trials, provide the rationale for assessing Aramchol in further clinical studies in patients with biliary fibrosis, particularly PSC, where a treatment is desperately needed.

Abstract 4128491: Dietary N-3 Very-Long-Chain Polyunsaturated Fatty Acids Improve Retinal Function And Reduce Aortic Atherosclerosis In ApoE-Deficient Mice

Introduction: N-3 very-long-chain polyunsaturated fatty acids (VLCPUFA; C≥24), which are found primarily in retina and a few other select tissues, are known to play critical roles in specific biological systems. Although n-3 PUFA, such as eicosapentanoic acid (EPA, C20:5 n-3) and docosahexaenoic acid (DHA, C22:6 n-3), may confer cardiovascular benefits, they did not improve age-related macular degeneration (AMD), a leading cause of blindness worldwide, in clinical trials. The activity of ELOVL fatty acid elongase 2 (ELOVL2), an enzyme that converts EPA into tetracosapentaenoic acid (TPA, C24:5 n-3), is known to decrease in the retina with age due to promoter methylation. Hypothesis: We hypothesized that dietary VLCPUFA may delay or prevent AMD, by bypassing the ELOVL2-mediated lipid elongation step. We also hypothesize that VLCPUFA may benefit cardiometabolic health like shorter-chain n-3 PUFA through similar mechanisms. Aims: We aimed to investigate the effect of dietary VLCPUFA on retinal function and cardiometabolic risk factors in mice. Methods: We have produced a new fish oil that contains ~40% (w/w) of C24-C28-rich VLCPUFA. We fed 9-month-old ApoE -/- mice with normal or VLCPUFA fortified diet (1% or 3% (w/w)) for 8 weeks, and age-matched C57BL/6J mice were used as control. We conducted electroretinography (ERG) and cognitive ability tests at the end of feeding period. In in vitro studies, we performed PPAR reporter assay and investigated the anti-inflammatory effects of TPA in lipopolysaccharide-stimulated RAW264.7 cells. Results: Supplementation of VLCPUFA showed a significant and dose-dependent improvement in ERG response. Like EPA and DHA, we also observed favorable cardiometabolic changes and decreased atherosclerotic plaque area due to dietary VLCPUFA. Intriguingly, VLCPUFA supplemented aging mice exhibit better cognitive performance compared with control. Transcriptome analysis revealed that VLCPUFA-enriched fish oil favorably regulated genes involved in nuclear receptor signaling pathways, lipid metabolism and inflammation. Furthermore, purified TPA potently activates PPARs, and suppressed inflammation in macrophage cells. Conclusions: Overall, our studies revealed for the first time several potential health benefits for our new VLCPUFA-enriched fish oil in several age-related diseases and support its future development as a new dietary supplement.

TMET-34. PYROPTOSIS IS AN ACQUIRED VULNERABILITY OF BRAIN METASTASES

Abstract Metastasis, the spread of cancer cells from one part of the body to another, is a leading cause of death among cancer patients. Three particularly dangerous forms of metastases are the spread of lung, skin, and breast cancers to the brain. On average survival time of all brain metastasis (BM) patients is around 4 months, which is accompanied by a failing and undefined standard of care. We have strived to bridge the gap between novel safe therapeutics and brain metastasis patients by discovering and targeting metabolic vulnerabilities in brain metastases. Here, we conducted comparative metabolomic screening in patient-derived BM lines versus normal brain cells to identify dihydroorotate dehydrogenase (DHODH) as a cancer-selective targetable vulnerability. DHODH is an essential enzyme that is located within the inner membrane of the mitochondria which has a primary role in producing pyrimidine metabolites through the de novo uridine synthesis pathway and also contributes to the proper functioning of the electron transport chain. Through this, DHODH has been implicated in the essential functioning of energy metabolism, DNA and RNA synthesis, and most recently in the modulation of the immune system. In our studies we have elucidated the significant effect DHODH inhibitors and the induction of DHODH CRISPR knock-out has against the cell viability, sphere formation, and proliferation of patient derived BM samples in vitro and in vivo. Furthermore, through metabolomics we have discovered that following DHODH perturbation, there is a significant increase in a signaling lipid (D-ethryo-Dihydrosphingosine) that specifically inhibits Protein Kinase C (PKC) and initiates Gasdermin E (GSDME) mediated pyroptosis. By uncovering this mechanism we have discovered GSDME mediated pyroptosis is an aquired vulnerability of brain metastases. Overall, this study highlights the translational potential of DHODH inhibitors in BM and elucidates novel mechanistic underpinnings of nucleotide deprivation within the context of cell death.

CSIG-33. CERAMIDE-1-PHOSPHATE/CERK ARE REGULATORS OF ETMR GROWTH AND POTENTIAL THERAPEUTIC TARGETS

Abstract Embryonal tumor with multilayered rosettes (ETMR) is a highly aggressive CNS neoplasm which occurs almost exclusively in infants and is associated with an extremely poor prognosis. To identify functional signaling lipids that contribute to the aggressive nature of ETMR and that can be targeted therapeutically, we carried out mass spectrometry imaging on human ETMR patient samples, the patient-derived cell line BT183, and normal neural stem cells. We identified an accumulation of ceramide-1-photphate (C1P) within the rapidly proliferating embryonal tumor cells in patient samples and the cell model. We also detected high accumulation of C1P within the aberrant vascular proliferations in patient samples. Ceramide-1-phosphate is a pleiotropic bioactive signaling lipid that controls cell fate. C1P and its synthesizing enzyme, ceramide kinase (CERK), are known mitogens that have been shown to regulate cell proliferation in several non-CNS cancers. C1P is known to mediate the upregulation of PI3K/Akt/mTOR, MAPK/MEK/ERK1/2, Rho kinase, JNK, to promote cell survival and migration. After spatially mapping C1P accumulation in patient samples and our in vitro 3D models, we next carried out IHC to correlate lipid accumulation with its synthesizing enzyme, CERK. CERK was found to be abundantly accumulated in both endothelial and tumor cells within the tumor microenvironment of patient samples. Western blot analysis of CERK demonstrated a significant increase in the ETMR 3D tumorspheres compared to the NSC neurospheres. Treatment of the ETMR 3D tumorspheres with the CERK inhibitor, NVP-231, potently reduced cell growth and viability. Western blot analysis of ETMR tumorspheres at 8 and 24 hours post-treatment demonstrated a time-dependent decrease in N-MYC and a subsequent increase in p53. Studies are ongoing to validate these findings in vivo and to elucidate the signaling pathways that C1P/CERK regulate in both the vascular and tumor cells in ETMR.

NIMG-69. INTERROGATION OF GLIOBLASTOMA FATTY-ACID SYNTHESIS AND METABOLISM WITH DEUTERIUM METABOLIC IMAGING

Abstract Glioblastoma, an invariably lethal brain tumor, undergoes marked metabolic alterations during tumorigenesis and is extraordinarily difficult to treat. Detecting recurrence after treatment and understanding metabolic alterations within the tumor microenvironment are extremely challenging. An exciting and emerging imaging methodology, deuterium metabolic imaging (DMI), detects metabolic adaptations via non-radioactively labeled deuterated substrates. This study developed approaches to image lipid synthesis with deuterium oxide (D2O) and metabolism with D31-palmitate (D31-Pal) in glioblastoma. A fatty-acid phantom was generated for characterization of lipid DMI signal at 12 T. DMI was performed in mice orthotopically implanted with GL261 glioblastoma utilizing either orally administered D31-Pal or D2O and was correlated with pharmacokinetic metabolic measurements from mouse serum. Mice were either orally gavaged with an emulsion of D31-Pal prior to imaging or provided 16% D2O for ad libitum consumption following tumor implantation. Although D2O administration resulted in robust enrichment of lipid signal in GBM, D31-Pal uptake and metabolism were not significantly detected within intracranial tumors. Interestingly, D31-Pal uptake and metabolism were detected in normal tissues, indicating preferential utilization of fatty acids in non-neoplastic tissues. These findings suggest de novo lipogenesis within GBM, rather than uptake of administered long chain fatty acids, is the preferential pathway for cellular lipids. DMI can assist in interrogating GBM fatty-acid synthesis and metabolism, as well as furthering our understanding of lipid distribution within the body by providing a non-invasive scaffold for dynamic interrogation of fatty-acid distribution in an oncologic model. Developing a non-invasive method for characterization of tumor fatty-acid synthesis and metabolism may improve our understanding of tumor metabolism and could dynamically guide selection of patient-tailored metabolic therapies in the future.

Metabolic abnormalities and reprogramming in cats with naturally occurring hypertrophic cardiomyopathy.

The heart is a metabolic organ rich in mitochondria. The failing heart reprograms to utilize different energy substrates, which increase its oxygen consumption. These adaptive changes contribute to increased oxidative stress. Hypertrophic cardiomyopathy (HCM) is a common heart condition, affecting approximately 15% of the general cat population. Feline HCM shares phenotypical and genotypical similarities with human HCM, but the disease mechanisms for both species are incompletely understood. Our goal was to characterize global changes in metabolome between healthy control cats and cats with different stages of HCM. Serum samples from 83 cats, the majority (70/83) of which were domestic shorthair and included 23 healthy control cats, 31 and 12 preclinical cats with American College of Veterinary Internal Medicine (ACVIM) stages B1 and B2, respectively, and 17 cats with history of clinical heart failure or arterial thromboembolism (ACVIM stage C), were collected for untargeted metabolomic analysis. Multiple linear regression adjusted for age, sex and body weight was applied to compare between control and across HCM groups. Our study identified 1253 metabolites, of which 983 metabolites had known identities. Statistical analysis identified 167 metabolites that were significantly different among groups (adjusted P<0.1). About half of the differentially identified metabolites were lipids, including glycerophospholipids, sphingolipids and cholesterol. Serum concentrations of free fatty acids, 3-hydroxy fatty acids and acylcarnitines were increased in HCM groups compared with control group. The levels of creatine phosphate and multiple Krebs cycle intermediates, including succinate, aconitate and α-ketoglutarate, also accumulated in the circulation of HCM cats. In addition, serum levels of nicotinamide and tryptophan, precursors for de novo NAD+ biosynthesis, were reduced in HCM groups versus control group. Glutathione metabolism was altered. Serum levels of cystine, the oxidized form of cysteine and cysteine-glutathione disulfide, were elevated in the HCM groups, indicative of heightened oxidative stress. Further, the level of ophthalmate, an endogenous glutathione analog and competitive inhibitor, was increased by more than twofold in HCM groups versus control group. Finally, several uremic toxins, including guanidino compounds and protein bound putrescine, accumulated in the circulation of HCM cats. Our study provided evidence of deranged energy metabolism, altered glutathione homeostasis and impaired renal uremic toxin excretion. Altered lipid metabolism suggested perturbed structure and function of cardiac sarcolemma membrane and lipid signalling.

Direct lipid interactions control SARS-CoV-2 M protein conformational dynamics and virus assembly.

M is the most abundant structural membrane protein in coronaviruses and is essential for the formation of infectious virus particles. SARS-CoV-2 M adopts two conformations, M short and M long , and regulated transition between states is hypothesized to coordinate viral assembly and budding. However, the factors that regulate M conformation and roles for each state are unknown. Here, we discover a direct M-sphingolipid interaction that controls M conformational dynamics and virus assembly. We show M binds Golgi-enriched anionic lipids including ceramide-1-phosphate (C1P). Molecular dynamics simulations show C1P interaction promotes a long to short transition and energetically stabilizes M short . Cryo-EM structures show C1P specifically binds M short at a conserved site bridging transmembrane and cytoplasmic regions. Disrupting M short -C1P interaction alters M subcellular localization, reduces interaction with Spike and E, and impairs subsequent virus-like particle cell entry. Together, these results show endogenous signaling lipids regulate M structure and support a model in which M short is stabilized in the early endomembrane system to organize other structural proteins prior to viral budding.

Field monitoring of copepodamides using a new application for solid phase adsorption toxin tracking

AbstractChemical signaling is ubiquitous in the marine environment. Plankton rely on chemical signals to find mates, hunt prey, and respond to threats, and these small‐scale interactions can propagate into community‐wide cascades and large‐scale ecological changes. The chemical signaling exchange in the open ocean is poorly understood, and fundamental information about concentrations and spatiotemporal variability is lacking. Passive sampling has been used to monitor a wide range of dissolved chemicals, including anthropogenic pollutants and harmful algal toxins, but it is not generally applied to the study of marine chemical ecology. Here we test the compatibility of two resins commonly used for passive sampling via solid phase adsorption toxin tracking (SPATT), Diaion® HP20 and Sepabeads® SP207, with copepodamides, a group of polar lipid signaling compounds produced by copepods. We developed extraction and analysis methods that align with current SPATT practices for algal toxins and show the first measurements of copepodamides from Monterey Bay in California. In lab trials, mean copepodamide recovery from HP20 resin was approximately 240% greater than SP207. In addition, copepodamides were found to have a mean half‐life of 34 h in seawater. Adsorption to HP20 stabilized dissolved copepodamides, increasing the mean recovery after 168 h from 0.62% in seawater to 65.2% from SPATT. Results suggest that SPATT is a sensitive and effective tool for obtaining integrated copepodamide concentrations, spotlighting a novel method to include information from copepod mesozooplankton in time series and field studies.

Hyssopus cuspidatus extract inhibited OVA-sensitized allergic asthma through PI3K/JNK/P38 signaling pathway and lipid homeostasis regulation

ObjectiveTo investigate the effect and mechanism of Hyssopus cuspidatus Boriss. extract (HCE) in ovalbumin (OVA)-induced allergic asthma. MethodsComponents identification of HCE was conducted using ultra performance liquid chromatography-quadrupole-time of flight-mass spectrometry. Mice were sensitized with OVA to establish asthmatic model, and dexamethasone was used as positive control. Respiratory reactivity, white cells counting in bronchoalveolar lavage fluid and peripheral blood, cytokine level measurement in serum and lung tissue, and histologic examination were performed to evaluate the therapeutic effect of HCE on asthma. Network pharmacology approach was used for mechanism prediction. Western blotting and untargeted lipidomics method were applied for mechanism validation. ResultsFifty-two compounds were identified in HCE, predominantly terpenoids and flavonoids. HCE markedly reduced airway resistance, the eosinophil infiltration in lung tissues, and the levels of immunoglobulin E, interleukin-4, interleukin-5, and interleukin-13. Network pharmacology analysis suggested phosphatidylinositol 3-kinases (PI3K), c-Jun N-terminal kinase (JNK), and p38 Mitogen-activated protein kinase (P38) may be key proteins of HCE in the treatment of allergic asthma. Western blot results indicated that the levels of phosphorylated PI3K, JNK, and P38 were downregulated in HCE-treated group. Moreover, HCE significantly upregulated the levels of ceramide and sphingomyelin and downregulated the level of phosphatidylcholine ConclusionHCE inhibited allergic asthma via PI3K/JNK/P38 signaling pathway and lipid homeostasis regulation.

Multi-Omic characterization of the effects of Ocrelizumab in patients with relapsing-remitting multiple sclerosis

The study examined changes in the plasma proteome, metabolome, and lipidome of N = 14 patients with relapsing-remitting multiple sclerosis (RRMS) initiating treatment with ocrelizumab, assayed at baseline, 6 months, and 12 months. Analyses of >4000 circulating biomarkers identified depletion of B-cell associated proteins as the early effect observed following ocrelizumab (OCR) initiation, accompanied by the reduction in plasma abundance of cytokines and cytotoxic proteins, markers of neuronaxonal damage, and biologically active lipids including ceramides and lysophospholipids, at 6 months. B-cell depletion was accompanied by decreases in B-cell receptor and cytokine signaling but a pronounced increase in circulating plasma B-cell activating factor (BAFF). This was followed by an upregulation of a number of signaling and metabolic pathways at 12 months. Patients with higher baseline brain MRI lesion load demonstrated both higher levels of cytotoxic and structural proteins in plasma at baseline and more pronounced biomarker change trajectories over time. Digital cytometry identified a putative increase in myeloid cells and a pro-inflammatory subset of T-cells. Therapeutic effects of ocrelizumab extend beyond CD20-mediated B-cell lysis and implicate metabolic reprogramming, juxtaposing the early normalization of immune activation, cytokine signaling and metabolite and lipid turnover in periphery with changes in the dynamics of immune cell activation or composition. We identify BAFF increase following CD20 depletion as a tentative compensatory mechanism that contributes to the reconstitution of targeted B-cells, necessitating further research.

Mechanisms coupling lipid droplets to MASLD pathophysiology.

Hepatic steatosis, the buildup of neutral lipids in lipid droplets (LDs), is commonly referred to as metabolic dysfunction-associated steatotic liver disease (MASLD) when alcohol or viral infections are not involved. MASLD encompasses simple steatosis and the more severe metabolic dysfunction-associated steatohepatitis (MASH), characterized by inflammation, hepatocyte injury, and fibrosis. Previously viewed as inert markers of disease, LDs are now understood to play active roles in disease etiology and have significant non-pathological and pathological functions in cell signaling and function. These dynamic properties of LDs are tightly regulated by hundreds of proteins that coat the LD surface, controlling lipid metabolism, trafficking, and signaling. The following review highlights various facets of LD biology with the primary goal of discussing key mechanisms through which LDs can promote the development of advanced liver diseases including MASH.