Fatty Acid Metabolism Research Articles

The effects of PstR, a PadR family transcriptional regulatory factor, in Plesiomonas shigelloides are revealed by transcriptomics.

Plesiomonas shigelloides is a gram-negative opportunistic pathogen associated with gastrointestinal and extraintestinal diseases in humans. There have been reports of specific functional genes in the study of P. shigelloides, but there are also many unknown genes that may play a role in P. shigelloides pathogenesis as global regulatory proteins or virulence factors. In this study, we found a transcriptional regulator of the PadR family in P. shigelloides and named it PstR (GenBank accession number: EON87311.1), which is present in various pathogenic bacteria but whose function has rarely been reported. RNA sequencing (RNA-Seq) was used to analyze the effects of PstR on P. shigelloides, and the results indicated that PstR regulates approximately 9.83% of the transcriptome, which includes impacts on motility, virulence, and physiological metabolism. RNA-seq results showed that PstR positively regulated the expression of the flagella gene cluster, which was also confirmed by quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) and Luminescence screening assay. Meanwhile, the ΔpstR mutant strains lacked flagella and were non-motile, as confirmed by motility assays and transmission electron microscopy (TEM). Additionally, PstR also positively regulates T3SS expression, which aids in P. shigelloides' capacity to infect Caco-2 cells. Meanwhile, we also revealed that PstR negatively regulates fatty acid degradation and metabolism, as well as the regulatory relationship between PsrA, a regulator of fatty acid degradation and metabolism, and its downstream genes in P. shigelloides. Overall, we revealed the effects of PstR on motility, virulence, and physiological metabolism in P. shigelloides, which will serve as a foundation for future research into the intricate regulatory network of PstR in bacteria.

Investigating the diagnostic and prognostic significance of genes related to fatty acid metabolism in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most prevalent and lethal cancers worldwide, with death rates increasing by approximately 2-3% per year. The high mortality and poor prognosis of HCC are primarily due to inaccurate early diagnosis and lack of monitoring when liver transplantation is not feasible. Fatty acid (FA) metabolism is a critical metabolic pathway that provides energy and signaling factors in cancer, particularly in HCC, and promotes malignancy. Therefore, it is essential to explore specific FA metabolism-related diagnostic and prognostic signatures that can enable the effective early diagnosis and monitoring of HCC. In this study, we used genes associated with FA metabolism pathway and weighted gene co-expression network analysis (WGCNA) to establish a gene co-expression network and identify hub genes related to HCC (disease WGCNA) and FA clusters (cluster WGCNA). A diagnostic model was constructed using data downloaded from the Gene Expression Omnibus database (GSE25097), and a prognostic model was established using The Cancer Genome Atlas cohort, in which Univariate Cox regression analysis, multivariate Cox risk model, and LASSO Cox regression analysis were applied. The immune infiltration of HCC cells was evaluated using CIBERSORT. The function of the key SLC22A1 gene was experimentally verified in vitro and in vivo. Twelve overlapping genes (CPEB3, ASPDH, DEPDC7, ETFDH, UGT2B7, GYS2, F11, ANXA10, CYP2C8, GLYATL1, C6, and SLC22A1) from disease and cluster WGCNA were identified as key genes and used in the construction of the diagnostic and prognostic models. The RF model had the highest area under the ROC curve (AUC) of 0.994 was identified as the most effective for distinguishing patients with HCC with different features. The top five important genes (C6, UGT2B7, SLC22A1, F11, and CYP2C8) from the RF model were selected as diagnostic genes for further analysis (ROC curves: AUC value = 0.986, 95% confidence interval [95% CI] = 0.967-0.999). Moreover, a risk score formula consisting of four genes (GYS2, F11, ANXA10 and SLC22A1) was established and its independent prognostic ability was further demonstrated (univariate Cox regression analysis: hazard ratio [HR] = 3.664%, 95% CI = 2.033-6.605, P < 0.001; multivariate Cox regression analysis: HR = 2.801%, 95% CI = 1.553-5.049, P < 0.001). Additionally, in vitro and in vivo experiments demonstrated that SLC22A1 inhibits HCC tumor development, suggesting it may be a potential therapeutic target for HCC. These findings indicate a considerable value of specific FA metabolism-related genes in the diagnostic and prognostic evaluation of HCC, which provide novel insights into the disease's management, as well as has potential implications for personalized treatment strategies. However, further investigation of the effects of these model genes on HCC is required.

Integrated virtual screening and MD simulation study to discover potential inhibitors of mycobacterial electron transfer flavoprotein oxidoreductase.

Tuberculosis (TB) continues to be a major global health burden, with high incidence and mortality rates, compounded by the emergence and spread of drug-resistant strains. The limitations of current TB medications and the urgent need for new drugs targeting drug-resistant strains, particularly multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB, underscore the pressing demand for innovative anti-TB drugs that can shorten treatment duration. This has led to a focus on targeting energy metabolism of Mycobacterium tuberculosis (Mtb) as a promising approach for drug discovery. This study focused on repurposing drugs against the crucial mycobacterial protein, electron transfer flavoprotein oxidoreductase (EtfD), integral to utilizing fatty acids and cholesterol as a carbon source during infection. The research adopted an integrative approach, starting with virtual screening of approved drugs from the ZINC20 database against EtfD, followed by molecular docking, and concluding with molecular dynamics (MD) simulations. Diacerein, levonadifloxacin, and gatifloxacin were identified as promising candidates for repurposing against TB based on their strong binding affinity, stability, and interactions with EtfD. ADMET analysis and anti-TB sensitivity predictions assessed their pharmacokinetic and therapeutic potential. Diacerein and levonadifloxacin, previously unexplored in anti-tuberculous therapy, along with gatifloxacin, known for its efficacy in drug-resistant TB, have broad-spectrum antimicrobial properties and favorable pharmacokinetic profiles, suggesting potential as alternatives to current TB treatments, especially against resistant strains. This study underscores the efficacy of computational drug repurposing, highlighting bacterial energy metabolism and lipid catabolism as fruitful targets. Further research is necessary to validate the clinical suitability and efficacy of diacerein, levonadifloxacin, and gatifloxacin, potentially enhancing the arsenal against global TB.

Activating PPARβ/δ-Mediated Fatty Acid β-Oxidation Mitigates Mitochondrial Dysfunction Co-induced by Environmentally Relevant Levels of Molybdenum and Cadmium in Duck Kidneys.

Cadmium (Cd) and high molybdenum (Mo) pose deleterious effects on health. Prior studies have indicated that exposure to Mo and Cd leads to damage in duck kidneys, but limited studies have explored this damage from the perspective of fatty acid metabolism. In this study, 40 healthy 8-day-old ducks were randomly assigned to four groups and fed a basic diet containing Cd (4mg/kg Cd) or Mo (100mg/kg Mo) or both. Kidney tissues were harvested on the 16th week. Results demonstrated that Cd and/or Mo inhibited mitochondrial fatty acid β-oxidation and disrupted mitochondrial dynamics, along with significant suppression of peroxisome proliferator-activated receptor β/δ (PPARβ/δ) protein in duck kidneys. In vitro study, duck renal tubular epithelial cells were exposed for 12h to either Mo (480μM Mo), Cd (2.5μM Cd), and GW0742 (0.3μM, a potent agonist of PPARβ/δ) alone or in combination. The results demonstrated that Cd and/or Mo led to marked fatty acid oxidation deficiency and mitochondrial dysfunction and that PPARβ/δ protein was involved in the process. Altogether, this study found that activating PPARβ/δ-mediated fatty acid β-oxidation mitigates mitochondrial dysfunction co-induced by Mo and Cd in duck kidneys.

Light up heart-type fatty acid binding protein (FABP3) with a novel fluorine-18 labelled selective FABP3 ligand.

Heart-type fatty acid binding proteins (FABP3) constitute a family of lipid chaperone proteins. They are found in the cytosol and enhance cellular fatty acid solubilisation, transport, and metabolism. FABP3 is highly expressed in the myocardium and is released from myocytes during myocardial damage. As FABP3 content in the myocardium is closely related to the metabolic state of fatty acids, we hypothesised that targeting of FABP3 with a radiolabelled small organic compound would visualise myocardium. The selective FABP3 inhibitor, 4-(4-fluoro-2-(1-phenyl-5-(2-(trifluoromethyl)phenyl)-1H-pyrazol-3-yl)phenoxy)butanoic acid (LUF), was radiolabelled via a two-step reaction comprising copper-mediated 18F-fluorination of an arylboronic precursor followed by alkaline hydrolysis of the ethoxy protecting group. [18F]LUF was successfully synthesised by automated synthesiser with sufficient activity yields (14.0 ± 1.8 GBq) and high quality (molar activity, > 250 GBq/µmol and radiochemical purity, > 99.6%). Biological assessment of [18F]LUF as an in vivo myocardial imaging agent included evaluations of biodistribution, metabolite analysis, and positron emission tomography (PET) imaging of small animals. [18F]LUF clearly visualised the myocardium with high contrast against background tissues such as the lung and liver. [18F]LUF also showed a high absolute myocardial uptake equivalent to that of the promising myocardial perfusion tracer [18F]flurpiridaz and excellent metabolic stability in the body. These properties are ideal for stable and noise-less imaging of the heart. PET imaging of rat surgical permanent myocardial infarction (MI) and experimental autoimmune myocarditis (EAM) was also performed. [18F]LUF successfully visualised lesions of permanent MI and EAM. Our results showed for the first time that the 18F-labelled FABP3 selective small organic compound clearly visualised myocardium with good quality. To determine the clinical utility of [18F]LUF for cardiovascular disease in clinical practice, it will be necessary to evaluate a greater variety of cardiovascular disease models and elucidate the accumulation mechanism, particularly in relation to fatty acid metabolism in the myocardium.

Adipocyte associated glucocorticoid signaling regulates normal fibroblast function which is lost in inflammatory arthritis.

Fibroblasts play critical roles in tissue homeostasis, but in pathologic states they can drive fibrosis, inflammation, and tissue destruction. Little is known about what regulates the homeostatic functions of fibroblasts. Here, we perform RNA sequencing and identify a gene expression program in healthy synovial fibroblasts characterized by enhanced fatty acid metabolism and lipid transport. We identify cortisol as the key driver of the healthy fibroblast phenotype and that depletion of adipocytes, which express high levels of Hsd11b1, results in loss of the healthy fibroblast phenotype in mouse synovium. Additionally, fibroblast-specific glucocorticoid receptor Nr3c1 deletion in vivo leads to worsened arthritis. Cortisol signaling in fibroblasts mitigates matrix remodeling induced by TNF and TGF-β1 in vitro, while stimulation with these cytokines represses cortisol signaling and adipogenesis. Together, these findings demonstrate the importance of adipocytes and cortisol signaling in driving the healthy synovial fibroblast state that is lost in disease.

Abstract 4136030: Fatty acids disturb cardiomyocyte proliferation by increasing PDK4 and HMGCS2 via PPARδ activation

Background: Almost all cardiac diseases are difficult to cure entirely because cardiomyocytes rarely proliferate to recover cardiac damage. In fact, most mammals have a capacity to regenerate cardiomyocytes immediately after birth. Newborn infant drastically changes cardiac metabolism from glycolysis to oxidative phosphorylation using fatty acids. Previous research revealed that lipid metabolism had a negative influence on cardiomyocyte cell cycle but the mechanism has not been clarified completely. Objective: This study was performed to elucidate the way fatty acid metabolism affects cardiomyocyte proliferation. Methods and results: Isolated and cultured neonatal rat cardiomyocytes (NRCM) were treated with the mixture of palmitic acid, oleic acid, and L-carnitine (FA mix) for 24 hours. Realtime RT-PCR revealed that FA mix increased the mRNA expressions of pyruvate dehydrogenase kinase 4 (PDK4), a fatty acid metabolism regulator, and HMG-CoA synthase 2 (HMGCS2), a ketogenic factor, as well as β-oxidation-related enzymes in dose dependent manner. Simultaneously, the results of immunofluorescent staining showed that FA mix decreased cardiomyocytes expressing Ki67, a cell cycle marker. GW501516, a peroxisome proliferator-activated receptor δ (PPARδ) agonist, also increased fatty acid metabolism factors with the reduction of Ki67 positive cardiomyocytes, whereas fenofibrate, a PPARα agonist, or pioglitazone, a PPARγ agonist, caused little or no change in these phenotypes. Moreover, NRCM pretreated with GSK3787, a PPARδ antagonist, before FA mix stimulation suppressed the upregulations of fatty acid metabolism factors and the reduction of Ki67 expressing cardiomyocytes. Finally, the lentiviral vectors which expressed PDK4 or HMGCS2 were produced to investigate these proteins suppressed NRCM cell cycle directly. Either overexpressing PDK4 or HMGCS2 decreased Ki67 positive NRCM without the upregulation of each other or β-oxidation-related enzymes. Conclusion: Fatty acids disturbed NRCM proliferation by upregulating PDK4 and HMGCS2 through the activation of PPARδ independently from β-oxidation.

Abstract 4116177: Metabolic and Pharmacokinetic Profiling of Ketone Ester by Background SGLT2 Inhibitor Therapy in Heart Failure with Reduced Ejection: A Phase I Clinical Trial

Background: Growing evidence supports a therapeutic role for ketones in HFrEF. However, no pharmacokinetic (PK) studies are available to guide further investigation, and uncertainty exists regarding use with the ketogenic SGLT2i and dose-dependent effects. Methods: We conducted a phase I trial of two doses of ketone ester (KE, 250 mg/kg and 500 mg/kg) in 20 HFrEF participants, stratified by SGLT2i use. Non-compartmental analysis assessed PK parameters of ketones. Paired t-tests and generalized linear mixed models assessed changes in mass-spectrometry based targeted metabolites, blood gas, and vital sign assessments up to 4 hours after dosing. Results: The mean age was 66.0±14.8 years, 45% were women, 30% were non-White, and average EF was 33±13%. The median (25 th –75 th percentile) T max , C max , and T 1/2 for total ketones with 250 and 500 mg/kg doses were 1.01 (0.64-1.24) and 1.58 (1.06-1.99) hours, 2317 (2165-2491) and 3354 (3291-3538) µM, and 0.85 (0.66-1.24) and 2.04 (1.36-3.47) hours, respectively ( Figure 1A ). One hour after KE consumption, insulin levels robustly increased, while non-esterified fatty acids, branched-chain amino acids, and acylcarnitines decreased except for C2/C4-OH acylcarnitines, which increased (FDR-adjusted p-value&lt;0.05). Increases in ketones and C2/C4-OH acylcarnitines were dose-dependent, while background SGLT2i was associated with blunting of the decrease across acylcarnitines. One hour post KE, heart rate initially rose by 4 (95%CI 2-6) beats/min, while systolic blood pressure (-7, 95%CI -12, -2 mmHg), pH (-0.07, 95%CI -0.08, 0.05), and bicarbonate (-3, 95%CI -4, -2 mEq/L) decreased, with dose-dependent acid-based effects ( Figures 1B-C ). These values returned close to baseline by 4 hours. Adverse events were infrequent and mild. Conclusions: Acute KE ingestion is associated with rapid changes in several key metabolic pathways, with differential effects imparted by background SGLT2i (fatty acid metabolism) and dose (ketone metabolism). Hemodynamic effects were transient and irrespective of dose/SGLT2i, while acidotic effects were heightened with increasing dose. These data support the safety of combined KE and SGLT2i in HFrEF and provide grounding data for further trials.

Abstract 4134475: Effects of E-cigarette Vaping on Endothelial Function in Diet-Induced Obese Mice

Introduction: Although electronic cigarettes (e-cigs) have been known to increase the risk of vascular complications, little is known about whether e-cig represents an independent risk factor for the development and worsening of obesity and its associated vascular diseases. We hypothesize that a high-fat diet (HFD) enhances e-cig-induced vascular complications. Methods: Male and female eight-week-old C57Bl/6J mice were fed normal chow (NC) or HFD for 15 weeks before being exposed to e-cigs (PG/VG only [PGVG] or PG/VG + 24 mg/ml nicotine [Nic]) or fresh air (FA) for 12 weeks (n=6-8). At the end of the experiments, glucose level and thoracic aortic responses to phenylephrine (PE), acetylcholine (ACh), and sodium nitroprusside (SNP) were assessed via the glucose tolerance test (GTT) and wire myography, respectively. Total RNA from male aortas was extracted and RNA-seq was utilized to identify the transcriptomic changes in our diet-induced obesity mouse model subjected to e-cig vapors (n=4). Results: Compared to NC with FA, HFD alone caused glucose intolerance as shown by the GTT, which was improved only by exposure to nicotine-containing e-cigs (HFD+Nic). Similar improvement in glucose intolerance were found in the NC group with e-cigs (PGVG or Nic). In addition, both NC and HFD-fed male mice exhibited endothelial dysfunction characterized by a decrease in the ACh-dependent (endothelium) relaxation of PE-induced contractions. Importantly, nicotine-containing e-cig exposure (Nic) dramatically reduced the sensitivity of the aorta in the HFD group (HFD+Nic) to both ACh and SNP, while it only affected the sensitivity and maximum relaxation to ACh in the male NC group (NC+Nic). There were no significant differences in the vasoreactivity of female mice exposed to e-cig or HFD. Finally, RNA-seq results suggested that e-cig-treated male mice had altered expression of genes related to endothelial and smooth muscle function and metabolism, particularly fatty acid metabolism, which was also significant with the addition of HFD. Conclusion: Collectively, our results suggest that acute e-cig exposure results in significant vascular dysfunction in male mice, which is worsened in HFD mice. The identification of genes dysregulated in mice exposed to e-cigs provides novel insights into vascular biology and could have a significant impact on our understanding of vascular complications associated with e-cig usage and provide insights into its contributions to obesity and diabetes.

Abstract 4115669: Single-cell and Spatial Transcriptomics Identified Fatty Acid-binding Proteins Controlling Endothelial Glycolytic and Arterial Programming in Pulmonary Hypertension

We are seeking to elucidate the endothelial fatty acid metabolism role for obstructive vascular remodeling in the pathogenesis of PAH. In this study, we bred a severe mouse model of PH Egln1 Tie2Cre mice with Fabp45 -/- mice to generate Egln1 Tie2Cre / Fabp45 -/- mice. We applied single-cell RNA sequencing (scRNA-seq) to profile the pulmonary cells in Egln1 Tie2Cre mice and Egln1 Tie2Cre / Fabp45 -/- mice. Human hPAEC from idiopathic PAH patients and healthy donors were used to measure fatty acid-binding protein 4 and 5 (FABP4 and FABP5) expression via sc-RNA seq and spatial transcriptomics. siRNA-mediated knockdown of FABP4 and FABP5 and lentivirus-mediated FABP4 and 5 overexpression were performed to study cell proliferation, apoptosis, and glycolysis. Our scRNA-seq analysis demonstrated that both FABP4 and 5 were highly induced in the ECs of Egln1 Tie2Cre mice. PAECs from IPAH patients also showed higher expression of FABP4 and 5. Knockdown of FABP4-5 reduced EC proliferation, starvation-induced Caspase 3/7 activity, and glycolysis. Overexpression of FABP4-5 promoted EC glycolysis and proliferation. Genetic deletion of Fabp4 and 5 in Egln1 Tie2Cre mice exhibited a reduction of RVSP, RV hypertrophy, and reduction of EC glycolysis gene programming compared to Egln1 Tie2Cre mice. In conclusion, we found that FABP4 and 5 control EC glycolysis and contribute to the development of PAH.

EPCO-57. INTEGRATED ANALYSIS OF BULK AND SINGLE-CELL RNA SEQUENCING DATA OF PRIMARY AND METASTATIC PEDIATRIC MEDULLOBLASTOMA

Abstract Medulloblastoma (MB) is a highly aggressive and the most common brain tumor in childhood. MB presents a high intertumoral heterogeneity, with at least four molecular subgroups identified (SHH, WNT, Group 3, and Group 4). Metastatic MB, or Leptomeningeal Disease (LMD), is predominantly found in the MB Group 3 type. Although LMD represents a main clinical challenge, its molecular mechanisms remain poorly characterized. Recent research has shown that primary and MB metastasis diverge dramatically. Our work has focused on establishing therapy naïve Group 3 Patient-Derived Xenografts models of primary and metastatic Medulloblastoma to conduct transcriptomic profiling at the bulk and single-nuclei RNAseq levels to identify genetic drivers/pathways that sustain leptomeningeal disease compartment. Our results show various signaling pathways enriched across LMD models, such as MYC targets, unfolded protein response, and fatty acid metabolism. Using single-sample GSEA analysis (ssGSEA) and deconvolution approaches, we have also identified that our PDXes models retain neoplastic subpopulations previously identified in MB single-cell sequencing studies. Similarly, we have identified slight differences in cell subpopulation proportions between primary and leptomeningeal compartments. Our single-nuclei studies have confirmed these results and differentially expressed genes previously found in bulk RNAseq analyses. These results suggest the presence of cell populations enriched in the metastatic compartment with an aberrant transcription phenotype and adaptations in fatty acid metabolism to survive the leptomeningeal space. In conclusion, our work supports the notion that primary and LMD retain subpopulation clusters present in MB Group 3 tumors with different proportions in the metastatic compartment shown by bulkRNAseq deconvolution and single nuclei RNA analysis. We also show that primary and LMD are transcriptionally different, with various enriched pathways in the metastatic compartment and shared among LMD Group 3 PDX models. Through these approaches, we aim to elucidate the genetic dependencies of metastatic Medulloblastoma that will help for targeted therapies.

DNAR-12. STEAROYL-COA DESATURASE REGULATES DNA DAMAGE REPAIR IN GBM BY MODULATING PARP1 ACTIVITY

Abstract Glioblastoma (GBM) is the most prevalent malignant brain cancer in adults, notorious for its aggressiveness and resistance to therapy. GBM patients commonly receive radiation therapy combined with temozolomide (TMZ), which engages tumor cells to promote lethal DNA damage and subsequent cytotoxicity. Active DNA repair mechanisms, particularly in a subset population of GBM stem-like cells (GSCs), drive therapeutic resistance, thus largely contributing to the bleak prognosis of GBM. Poly (ADP-ribose) polymerases (PARPs) are essential in various cellular processes, including DNA repair. We have previously reported that fatty acid desaturation mediated by Stearoyl-CoA desaturase 1 (SCD1) plays a cytoprotective role in GSCs. Inhibiting SCD prevents tumor initiation and inhibits DNA damage repair, hence sensitizing to radiation and TMZ. Yet, the mechanistic role of SCD in DNA damage regulation remained unknown. Here, we found that the expression of both human isoforms of SCD, SCD1, and SCD5, directly correlates with PARP protein levels and subcellular localization. Downregulating SCD1/5 in GSCs resulted in significantly lower levels of PARP1, coupled with increased DNA damage, as well as reduced DNA damage repair and chromosome assembly. Conversely, cells overexpressing SCD1/5 exhibited higher PARP1 expression and lower levels of basal DNA damage compared to control GSCs. Notably, SCD1/5 overexpression also led to increased resistance to TMZ. We show that SCD1/5 regulates PARP activity by controlling PARP1 subcellular localization. In addition to decreased total levels of PARP following SCD1/5 downregulation, we also found increased PARP1 self-PARylation. Using confocal microscopy, we show that when SCD1/5 is repressed, PARylated PARP translocates from the nucleus to the cytosol, rendering it unable to bind DNA and recruit DNA-repairing machinery. In conclusion, our study provides a direct link between fatty acid metabolism and PARP1-mediated DNA damage repair.

NIMG-62. SEX-DISTINCT TRANSCRIPTOMIC SIGNATURES UNDERLY MRI-DEFINED EDEMA PATTERNS IN HUMAN GLIOMAS

Abstract Magnetic resonance imaging (MRI) is key to clinically managing brain tumor patients, however connecting the biology to imaging remains challenging. We previously developed a two-compartment model of MRI signal intensity to quantitatively estimate relative edema abundance from T2-weighted MRIs. Using this model, we previously identified the fatty acid metabolism (FAM) and oxidative phosphorylation (OxPhos) pathways as sex-distinct, with both pathways amplified for high edema in males and low edema in females. The purpose of this project was to further delineate sex-distinct biology associated with MRI-estimated brain tumor edema abundance. We analyzed 179 multiregional samples (Female: 75; Male: 104) from 55 high grade glioma patients (Female: 21; Male: 34) for bulk RNA-Seq. Patients’ pre-surgical multiparametric MRIs were preprocessed and segmented for abnormal regions and normal tissue. Utilizing the segmentations and preprocessed images we estimated the relative fractions of extracellular and intracellular space based on the edema mathematical model. Samples were characterized by their edema scores, which were analyzed using differential expression for high and low edema, gene set enrichment analysis (GSEA) using MSigDB hallmarks, and leading edge interpretation. Based on transcriptomic leading edge analyses of high and low edema samples from sex-separated cohorts, we identified common and sex-distinct enrichment of the FAM and OxPhos pathways underlying edema patterns. Of the OxPhos pathway leading edge genes, 45 were common, 36 were unique to females, and 66 were unique to males. Of the FAM pathway leading edge genes, 8 were common, 39 were unique to females, and 29 were unique to males. Notably, expression of both IDH1 and IDH2 were increased for males in regions of high edema in the OxPhos pathway. IDH3a was decreased for females in regions of low edema in the OxPhos pathway. These data suggest that there may be sex-distinct metabolism underlying MRI measurable edema formation.

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.

The Kinetics of Carbon-Carbon-Bond Formation in Metazoan Fatty Acid Synthase and its Impact on Product Fidelity.

Fatty acid synthase (FAS) multienzymes are responsible for de novo fatty acid biosynthesis and crucial in primary metabolism. Despite extensive research, the molecular details of the FAS catalytic mechanisms are still poorly understood. For example, the b-ketoacyl synthase (KS) catalyzes the fatty acid elongating carbon-carbon-bond formation, which is the key catalytic step in biosynthesis, but factors that determine the speed and accuracy of his reaction are still unclear. Here, we report enzyme kinetics of the KS-mediated carbon-carbon bond formation, enabled by a continuous fluorometric activity assay. We observe that the KS is likely rate-limiting to the fatty acid biosynthesis, its kinetics are adapted to the length of the bound fatty acyl chain, and that the KS is also responsible for the fidelity of biosynthesis by preventing intermediates from undergoing KS-mediated elongation. To provide mechanistic insight into KS selectivity, we performed computational molecular dynamics (MD) simulations. We identify positive cooperativity of the KS dimer, which we suggest to affect the conformational variability of the multienzyme. Advancing our knowledge about the KS molecular mechanism will pave the ground for engineering FAS for biotechnology applications and the design of new therapeutics targeting the fatty acid metabolism.

The Kinetics of Carbon‐Carbon‐Bond Formation in Metazoan Fatty Acid Synthase and its Impact on Product Fidelity

Fatty acid synthase (FAS) multienzymes are responsible for de novo fatty acid biosynthesis and crucial in primary metabolism. Despite extensive research, the molecular details of the FAS catalytic mechanisms are still poorly understood. For example, the b‐ketoacyl synthase (KS) catalyzes the fatty acid elongating carbon‐carbon‐bond formation, which is the key catalytic step in biosynthesis, but factors that determine the speed and accuracy of his reaction are still unclear. Here, we report enzyme kinetics of the KS‐mediated carbon‐carbon bond formation, enabled by a continuous fluorometric activity assay. We observe that the KS is likely rate‐limiting to the fatty acid biosynthesis, its kinetics are adapted to the length of the bound fatty acyl chain, and that the KS is also responsible for the fidelity of biosynthesis by preventing intermediates from undergoing KS‐mediated elongation. To provide mechanistic insight into KS selectivity, we performed computational molecular dynamics (MD) simulations. We identify positive cooperativity of the KS dimer, which we suggest to affect the conformational variability of the multienzyme. Advancing our knowledge about the KS molecular mechanism will pave the ground for engineering FAS for biotechnology applications and the design of new therapeutics targeting the fatty acid metabolism.

Omics studies in Behçet's disease.

In this review, we aimed to highlight recent findings from "-omics" studies in Behçet's disease. Recent genomic studies in Behçet's disease identified possible risk loci associated with Behçet's disease related uveitis, neurologic involvement and gastrointestinal involvement. Additionally, sex-specific genetic effects were determined in Behçet's disease. Transcriptomic analyses of immune cells in Behçet's disease revealed that key inflammatory pathways such as NF-κB and MAPK have roles in Behçet's disease pathogenesis. Proteomic studies have highlighted the role of immune cell derived extracellular vesicles and identified potential biomarkers for vascular involvement and examined HLA I-bound immunopeptidomes. Metabolomics studies are still limited, but recent research has pointed to alterations in fatty acid metabolism and lipid profiles in Behçet's disease patient. Omics studies have gained importance in the field of Behçet's disease through the generation of large data sets and efforts to extend their application are intensifying. These studies can provide opportunities for understanding Behçet's disease pathogenesis when they lead to testable hypotheses. Current challenges include the choice of appropriately homogeneous patient and control groups, effective data management and sharing, high cost and a rapidly increasing gap between the wealth of observational data generated and the relative paucity of controlled experimental efforts that could lead to mechanistic understanding.

Palmitoleic and oleic fatty acids as biomarkers for coronary heart disease: A predictive model.

saturated and unsaturated fatty acid showed a significant link with coronary artery health and disease. This study aimed to compare plasma levels of unsaturated fatty acids (UFAs) between individuals with coronary heart disease (CHD) and those without. It also investigated the association between specific UFA ratios and the presence or severity of acute coronary syndrome (ACS). Additionally, the study explored the potential of UFAs as biomarkers for assessing CHD risk or disease severity. Patients suspected of coronary heart disease (CHD) at Northern Jiangsu People's Hospital were categorized by coronary angiography into non-CHD (53 cases) and CHD (182 cases). The CHD group was divided into non-acute coronary syndrome (non-ACS) (40 cases) and ACS (142 cases) subgroups. The ACS group was further classified into unstable angina (61 cases), non-ST-elevation myocardial infarction (NSTEMI) (40 cases), and ST-elevation myocardial infarction (STEMI) (41 cases). Lipid profiles, myocardial injury markers, and fourteen unsaturated fatty acids were analyzed using liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). The CHD group had significantly higher triglycerides (TG), palmitoleic acid (PA), oleic acid (OA), docosahexaenoic acid (DHA), ω-6 fatty acids, and a higher ω-6/ω-3 ratio, but lower ω-3 fatty acids compared to non-CHD. In ACS, PA, LA, OA, and the ω-6/ω-3 ratio were elevated, while EPA and HDL were reduced. Logistic regression identified TG, ω-6/ω-3 ratio, PA, OA, and ω-6 fatty acids as risk factors, with ω-3 fatty acids being protective. PA was protective, while OA posed risk. A combined PA and OA model had a diagnostic efficacy (AUC 0.746). Altered fatty acid metabolism in CHD patients, particularly PA and OA, offers potential as biomarkers. The ω-6/ω-3 ratio is crucial for cardiovascular health.

Proteo-metabolomic insights for early dual physical and cognitive impairments: A search for biomarkers of healthy aging based on muscle-brain crosstalk.

We employed an untargeted proteo-metabolomic approach to profile circulating biomarkers in plasma samples from the I-Lan Longitudinal Aging Study, aiming to identify biomarkers and pathways associated with physio-cognitive decline syndrome (PCDS). In 115 propensity score-matched PCDS case-control pairs, pathway analyses implicated dysregulation of fatty acid metabolism and inflammation in PCDS pathogenesis. Sex-specific associations were observed, with disruptions in central carbon metabolism (elevated PKM, MDH1, and GAPDH; decreased MINPP1) and tyrosine metabolism (decreased MIF, DBH; increased thyroxine) characterizing in men. In contrast, perturbations in glutathione and phenylalanine metabolism, including increased ANPEP, GSTP1, and decreased pyroglutamic acid, were identified in women. Results suggest that dysregulated energy and redox homeostasis likely contribute to PCDS development. Notably, ANPEP, PKM, and MIF emerged as potential biomarkers, elucidating the muscle-brain crosstalk framework. Our findings provide insights into potential molecular mechanisms underlying PCDS and the muscle-brain crosstalk, marking progress toward elucidating biomarkers in the journey of healthy aging.

High-resolution chromosome-level genome of Scylla paramamosain provides molecular insights into adaptive evolution in crabs

BackgroundEvolutionary adaptation drives organismal adjustments to environmental pressures, exemplified in the diverse morphological and ecological adaptations seen in Decapoda crustaceans, particularly brachyuran crabs. Crabs thrive in diverse ecosystems, from coral reefs to hydrothermal vents and terrestrial habitats. Despite their ecological importance, the genetic mechanisms underpinning their developmental processes, reproductive strategies, and nutrient acquisition remain poorly understood.ResultsHere, we report a comprehensive genomic analysis of the green mud crab Scylla paramamosain using ultralong sequencing technologies, achieving a high-quality chromosome-level assembly. The refined 1.21 Gb genome, with an impressive contig N50 of 11.45 Mb, offers a valuable genomic resource. The genome exhibits 33,662 protein-coding genes, enriched in various pathways related to development and environmental adaptation. Gene family analysis shows expansion in development-related pathways and contraction in metabolic pathways, indicating niche adaptations. Notably, investigation into Hox gene regulation sheds light on their role in pleopod development, with the Abd-A gene identified as a linchpin. Post-transcriptional regulation involving novel-miR1317 negatively regulates Abd-A levels. Furthermore, the potential role of fru gene in ovarian development and the identification of novel-miR35 as a regulator of Spfru2 add complexity to gene regulatory networks. Comparative functional analysis across Decapoda species reveals neo-functionalization of the elovl6 gene in the synthesis of long-chain polyunsaturated fatty acids (LC-PUFA), suggesting its importance in environmental adaptation.ConclusionsOur findings shed light on various aspects of crab biology, including genome sequencing, assembly, and annotation, as well as gene family expansion, contraction, and regulatory mechanisms governing crucial developmental processes such as metamorphosis, reproductive strategies, and fatty acid metabolism.