Enzymes Of Fatty Acid Synthesis Research Articles

Arachidonic acid regulates pluripotency by modulating cellular energetics via fatty acid synthesis and mitochondrial fission

Arachidonic acid (AA) is an important omega-6 fatty acid that can be metabolised into an impressive spectrum of biologically active mediators participating in various cellular functions. Studies have shown that fatty acid synthesis is enhanced in embryonic stem cells (ESCs), and it is crucial for the cellular reprogramming of somatic cells into induced pluripotent stem cells (iPSCs). Fatty acid synthesis increases the cellular lipid contents and, in turn, promotes mitochondrial fission and cellular reprogramming. AA was found to induce acetyl-CoA carboxylase 1 (ACC1) expression, a major enzyme in fatty acid synthesis. In this study, we have investigated the regulation of pluripotency, fatty acid synthesis and mitochondrial activities of the human induced pluripotent stem cells (hiPSCs) and the human embryonal carcinoma (hEC) NTERA-2 cells upon treatment with varying concentrations of AA. Our results indicate that a lower concentration of AA can increase pluripotency, as evidenced by an increased expression of pluripotency markers, increased fatty acid synthesis as evidenced by lipid estimation and modulated mitochondrial fission, as evidenced by mitotracker staining for fissioned mitochondria. Moreover, higher concentrations of AA-induced the opposite effect, leading to pluripotent stem cell differentiation. Molecular docking simulations predicted the possible interactions between AA and its metabolites with fatty acid synthesis regulators ACC1 and CREB1 (Cyclic adenosine monophosphate Response Element Binding Protein 1) as a mechanism for AA regulating pluripotency.

Stearoyl-CoA desaturase 1 is targeted by EBV-encoded miR-BART20-5p and regulates cell autophagy, proliferation, and migration in EBV-associated gastric cancer.

Epstein-Barr virus (EBV) is the first human oncogenic virus known to express microRNAs (miRNAs), which are closely associated with the development of various tumors, including nasopharyngeal and gastric cancers. Stearoyl-CoA Desaturase 1 (SCD1) is a key enzyme in fatty acid synthesis, highly expressed in numerous tumors, promoting tumor growth and metastasis, making it a potential therapeutic target. In this study, we found that SCD1 expression in EBV-associated gastric cancer (EBVaGC) was significantly lower than in EBV-negative gastric cancer (EBVnGC) at both cellular and tissue levels. In addition, EBV-miR-BART20-5p targets the 3'-UTR of SCD1, downregulating its expression. Moreover, overexpression of SCD1 in EBVaGC cells promoted cell migration and proliferation while inhibiting autophagy. These results suggest that EBV-encoded miRNA-BART20-5p may contribute to EBVaGC progression by targeting SCD1.

De novo lipid synthesis and polarized prenylation drive cell invasion through basement membrane.

To breach the basement membrane, cells in development and cancer use large, transient, specialized lipid-rich membrane protrusions. Using live imaging, endogenous protein tagging, and cell-specific RNAi during Caenorhabditis elegans anchor cell (AC) invasion, we demonstrate that the lipogenic SREBP transcription factor SBP-1 drives the expression of the fatty acid synthesis enzymes POD-2 and FASN-1 prior to invasion. We show that phospholipid-producing LPIN-1 and sphingomyelin synthase SMS-1, which use fatty acids as substrates, produce lysosome stores that build the AC's invasive protrusion, and that SMS-1 also promotes protrusion localization of the lipid raft partitioning ZMP-1 matrix metalloproteinase. Finally, we discover that HMG-CoA reductase HMGR-1, which generates isoprenoids for prenylation, localizes to the ER and enriches in peroxisomes at the AC invasive front, and that the final transmembrane prenylation enzyme, ICMT-1, localizes to endoplasmic reticulum exit sites that dynamically polarize to deliver prenylated GTPases for protrusion formation. Together, these results reveal a collaboration between lipogenesis and a polarized lipid prenylation system that drives invasive protrusion formation.

Integrated multiple-omics reveals the regulatory mechanism underlying the effects of homologous Bacillus tequilensis (GCB-3) on growth performance of grass carp (Ctenopharyngodon idellus)

The purpose of this study was to investigate the regulatory mechanism of Bacillus tequilensis (GCB-3) in improving the growth performance of grass carp by microbiome and targeted metabolomics analysis. Fish were fed with different amounts of GCB-3 including B0 (0 CFU/g), B6 (1×106 CFU/g), B7 (1×107 CFU/g), B8 (1×108 CFU/g), and B9 (1×109 CFU/g) for 8 weeks. The results indicate that with the increase of dietary GCB-3 concentration, grass carp showed a significant linear trend in growth performance, and appetite factors showed a significant linear and quadratic trend, the growth performance and appetite-promoting factors in the B8 group reach their maximum value in the B8 group. Microbiome analysis found that Proteobacteria and Actinobacteria were the most abundant phylum in the gut microbiota of grass carp. The functional potential predicted that GCB-3 affected the synthesis and degradation of carbohydrates, amino acids, fatty acids and lipids. It found that GCB-3 also affected the tricarboxylic acid (TCA) cycle VII (acetate-producers) pathway. The results of targeted metabolomics showed a significant linear and quadratic increase in intestinal acetate with GCB-3 concentration and a maximum in the B8 group. The results of the correlation analysis showed a significant positive correlation between Actinobacteria abundance and acetic acid content, and also between TCA cycle VII (acetate-producers) pathway abundance and Actinobacteria abundance and acetic acid content. In B8 group, grass carp showed a faster regulation speed of blood glucose levels after glucose injection, and the GLP-1 content remained stable. The activities of glycolytic enzymes, lipolytic enzymes, protein metabolism enzymes, and their related mRNA expression levels in grass carp showed a linear or quadratic increasing trend. However, the expression levels of gluconeogenic enzymes and fatty acid synthesis enzyme related mRNA showed an opposite trend. In summary, the addition of 1×108 CFU/g GCB-3 in grass carp feed can improve the abundance of dominant bacterial phyla in the intestine, especially Actinobacteria, increase the concentration of intestinal acetate, provide substrate for the TCA cycle VII (acetate-producers) pathway, thereby regulating the nutrient metabolism of grass carp and ultimately promoting growth.

Hepatocyte-Specific Fads1 Overexpression Attenuates Western Diet-Induced Metabolic Phenotypes in a Rat Model.

Fatty acid desaturase 1 (FADS1) is a rate-limiting enzyme in long-chain polyunsaturated fatty acid (LCPUFA) synthesis. Reduced activity of FADS1 was observed in metabolic dysfunction-associated steatotic liver disease (MASLD). The aim of this study was to determine whether adeno-associated virus serotype 8 (AAV8) mediated hepatocyte-specific overexpression of Fads1 (AAV8-Fads1) attenuates western diet-induced metabolic phenotypes in a rat model. Male weanling Sprague-Dawley rats were fed with a chow diet, or low-fat high-fructose (LFHFr) or high-fat high-fructose diet (HFHFr) ad libitum for 8 weeks. Metabolic phenotypes were evaluated at the endpoint. AAV8-Fads1 injection restored hepatic FADS1 protein levels in both LFHFr and HFHFr-fed rats. While AAV8-Fads1 injection led to improved glucose tolerance and insulin signaling in LFHFr-fed rats, it significantly reduced plasma triglyceride (by ~50%) and hepatic cholesterol levels (by ~25%) in HFHFr-fed rats. Hepatic lipidomics analysis showed that FADS1 activity was rescued by AAV8-FADS1 in HFHFr-fed rats, as shown by the restored arachidonic acid (AA)/dihomo-γ-linolenic acid (DGLA) ratio, and that was associated with reduced monounsaturated fatty acid (MUFA). Our data suggest that the beneficial role of AAV8-Fads1 is likely mediated by the inhibition of fatty acid re-esterification. FADS1 is a promising therapeutic target for MASLD in a diet-dependent manner.

Central inhibition of stearoyl-CoA desaturase has minimal effects on the peripheral metabolic symptoms of the 3xTg Alzheimer’s disease mouse model

Evidence from genetic and epidemiological studies point to lipid metabolism defects in both the brain and periphery being at the core of Alzheimer’s disease (AD) pathogenesis. Previously, we reported that central inhibition of the rate-limiting enzyme in monounsaturated fatty acid synthesis, stearoyl-CoA desaturase (SCD), improves brain structure and function in the 3xTg mouse model of AD (3xTg-AD). Here, we tested whether these beneficial central effects involve recovery of peripheral metabolic defects, such as fat accumulation and glucose and insulin handling. As early as 3 months of age, 3xTg-AD mice exhibited peripheral phenotypes including increased body weight and visceral and subcutaneous white adipose tissue as well as diabetic-like peripheral gluco-regulatory abnormalities. We found that intracerebral infusion of an SCD inhibitor that normalizes brain fatty acid desaturation, synapse loss and learning and memory deficits in middle-aged memory-impaired 3xTg-AD mice did not affect these peripheral phenotypes. This suggests that the beneficial effects of central SCD inhibition on cognitive function are not mediated by recovery of peripheral metabolic abnormalities. Given the widespread side-effects of systemically administered SCD inhibitors, these data suggest that selective inhibition of SCD in the brain may represent a clinically safer and more effective strategy for AD.

Design, synthesis, and biological evaluation of carbazole derivatives as potent antibacterial agents targeting membrane function via FabH Inhibition

This study synthesized a series of carbazole compounds and tested their antimicrobial activity. Several of the synthesized compounds demonstrated potent inhibitory effects against Gram-negative bacteria. Molecular docking simulations with the fatty acid synthesis enzyme FabH revealed their potential antimicrobial action by interfering with fatty acid synthesis. Additionally, ADMET analysis confirmed favorable pharmacokinetic properties, providing a foundation for drug development and preclinical research. Furthermore, the optimized compound 2-(9HCarbazol-9-yl)-N-(4-(trifluoromethoxy)phenyl)acetamide was evaluated for its inhibitory and disruptive effects on biofilms using live/dead cell staining. The results demonstrated significant inhibition and disruption of biofilms, enhancing their antimicrobial efficacy. These findings offer valuable clues for the development of new antimicrobial drugs and hold promise for addressing the challenge of antimicrobial resistance with novel therapeutic strategies.

Breast Cancer: Mitochondria-Centered Metabolic Alterations in Tumor and Associated Adipose Tissue.

The close cooperation between breast cancer and cancer-associated adipose tissue (CAAT) shapes the malignant phenotype, but the role of mitochondrial metabolic reprogramming and obesity in breast cancer remains undecided, especially in premenopausal women. Here, we examined mitochondrial metabolic dynamics in paired biopsies of malignant versus benign breast tumor tissue and CAAT in normal-weight and overweight/obese premenopausal women. Lower protein level of pyruvate dehydrogenase and citrate synthase in malignant tumor tissue indicated decreased carbon flux from glucose into the Krebs cycle, whereas the trend was just the opposite in malignant CAAT. Simultaneously, stimulated lipolysis in CAAT of obese women was followed by upregulated β-oxidation, as well as fatty acid synthesis enzymes in both tumor tissue and CAAT of women with malignant tumors, corroborating their physical association. Further, protein level of electron transport chain complexes was generally increased in tumor tissue and CAAT from women with malignant tumors, respective to obesity. Preserved mitochondrial structure in malignant tumor tissue was also observed. However, mitochondrial DNA copy number and protein levels of PGC-1α were dependent on both malignancy and obesity in tumor tissue and CAAT. In conclusion, metabolic cooperation between breast cancer and CAAT in premenopausal women involves obesity-related, synchronized changes in mitochondrial metabolism.

RBM45 reprograms lipid metabolism promoting hepatocellular carcinoma via Rictor and ACSL1/ACSL4.

Reprogramming of lipid metabolism during hepatocarcinogenesis is not well elucidated. Here, we aimed to explore pivotal RNA-binding motif proteins (RBMs) in lipid metabolism and their therapeutic potential in hepatocellular carcinoma (HCC). Through bioinformatic analysis, we identified RBM45 as a critical gene of interest among differentially expressed RBMs in HCC, with significant prognostic relevance. RBM45 influenced the malignant biological phenotype and lipid metabolism of HCC cells. Mechanically, RBM45 promotes de novo lipogenesis in HCC by directly targeting two key enzymes involved in long-chain fatty acid synthesis, ACSL1 and ACSL4. RBM45 also targets Rictor, which has been demonstrated to modulate lipid metabolism profoundly. RBM45 also aided lipid degradation through activating a key fatty acid β oxidation enzyme, CPT1A. Thus, RBM45 boosted lipid synthesis and decomposition, indicating an enhanced utility of lipid fuels in HCC. Clinically, body mass index was positively correlated with RBM45 in human HCCs. The combination of a PI3K/AKT/mTOR pathway inhibitor in vitro or Sorafenib in orthotopic liver cancer mouse models with shRBM45 has a more significant therapeutic effect on liver cancer than the drug alone. In summary, our findings highlight the versatile roles of RBM45 in lipid metabolism reprogramming and its therapeutic potential in HCC. Lipids induced RBM45 expression. In turn, RBM45 promoted the utility of lipid in HCCs through accelerating both de novo lipogenesis and fatty acid β oxidation, which required the participation of Rictor, a core component of mTORC2 that has been demonstrated to modulate lipid metabolism potently, as well as ACSL1/ACSL4, two key enzymes of long-chain fatty acid synthesis. When the first-line chemotherapy drug sorafenib is combined with a PI3K/AKT/mTOR pathway inhibitor (MK2206 is an AKT inhibitor, rapamycin is a mTOR inhibitor, and inhibiting RBM45 can significantly inhibit Rictor), cell cycle, proliferation, lipid metabolism reprogramming, and hepatocarcinogenesis can be significantly inhibited, while apoptosis can be significantly enhanced.

The Identification of Functional Genes Affecting Fat-Related Meat Traits in Meat-Type Pigeons Using Double-Digest Restriction-Associated DNA Sequencing and Molecular Docking Analysis.

The Chinese indigenous Shiqi (SQ) pigeon and the imported White King (WK) pigeon are two meat-type pigeon breeds of economical and nutritional importance in China. They displayed significant differences in such meat quality traits as intramuscular fat (IMF) content and fatty acid (FA) compositions in the breast muscles. In this study, we aimed to screen candidate genes that could affect fat-related meat quality traits in meat-type pigeons. We investigated the polymorphic variations at the genomic level using double-digest restriction-associated DNA (ddRAD) sequencing in 12 squabs of SQ and WK pigeons that exhibited significant inter-breed differences in IMF content as well as FA and amino acid compositions in the breast muscles, and screened candidate genes influencing fat-related traits in squabs through gene ontology analysis and pathway analysis. By focusing on 6019 SNPs, which were located in genes with correct annotations and had the potential to induce changes in the encoded proteins, we identified 19 genes (ACAA1, ACAA2, ACACB, ACADS, ACAT1, ACOX3, ACSBG1, ACSBG2, ACSL1, ACSL4, ELOVL6, FADS1, FADS2, HACD4, HADH, HADHA, HADHB, MECR, OXSM) as candidate genes that could affect fat-related traits in squabs. They were significantly enriched in the pathways of FA metabolism, degradation, and biosynthesis (p < 0.05). Results from molecular docking analysis further revealed that three non-synonymous amino acid alterations, ACAA1(S357N), ACAA2(T234I), and ACACB(H1418N), could alter the non-bonding interactions between the enzymatic proteins and their substrates. Since ACAA1, ACAA2, and ACACB encode rate-limiting enzymes in FA synthesis and degradation, alterations in the enzyme-substrate binding affinity may subsequently affect the catalytic efficiency of enzymes. We suggested that SNPs in these three genes were worthy of further investigation into their roles in explaining the disparities in fat-related traits in squabs.

CDK13 promotes lipid deposition and prostate cancer progression by stimulating NSUN5-mediated m5C modification of ACC1 mRNA.

Cyclin-dependent kinases (CDKs) regulate cell cycle progression and the transcription of a number of genes, including lipid metabolism-related genes, and aberrant lipid metabolism is involved in prostate carcinogenesis. Previous studies have shown that CDK13 expression is upregulated and fatty acid synthesis is increased in prostate cancer (PCa). However, the molecular mechanisms linking CDK13 upregulation and aberrant lipid metabolism in PCa cells remain largely unknown. Here, we showed that upregulation of CDK13 in PCa cells increases the fatty acyl chains and lipid classes, leading to lipid deposition in the cells, which is positively correlated with the expression of acetyl-CoA carboxylase (ACC1), the first rate-limiting enzyme in fatty acid synthesis. Gain- and loss-of-function studies showed that ACC1 mediates CDK13-induced lipid accumulation and PCa progression by enhancing lipid synthesis. Mechanistically, CDK13 interacts with RNA-methyltransferase NSUN5 to promote its phosphorylation at Ser327. In turn, phosphorylated NSUN5 catalyzes the m5C modification of ACC1 mRNA, and then the m5C-modified ACC1 mRNA binds to ALYREF to enhance its stability and nuclear export, thereby contributing to an increase in ACC1 expression and lipid deposition in PCa cells. Overall, our results disclose a novel function of CDK13 in regulating the ACC1 expression and identify a previously unrecognized CDK13/NSUN5/ACC1 pathway that mediates fatty acid synthesis and lipid accumulation in PCa cells, and targeting this newly identified pathway may be a novel therapeutic option for the treatment of PCa.

Targeting ACC1 in T cells ameliorates psoriatic skin inflammation

Psoriasis is a chronic inflammatory skin disease driven by the IL-23/IL-17 axis. It results from excessive activation of effector T cells, including T helper (Th) and cytotoxic T (Tc) cells, and is associated with dysfunctional regulatory T cells (Tregs). Acetyl-CoA carboxylase 1 (ACC1), a rate-limiting enzyme of fatty acid synthesis (FAS), directs cell fate decisions between Th17 and Tregs and thus could be a promising therapeutic target for psoriasis treatment. Here, we demonstrate that targeting ACC1 in T cells by genetic ablation ameliorates skin inflammation in an experimental model of psoriasis by limiting Th17, Tc17, Th1, and Tc1 cells in skin lesions and increasing the frequency of effector Tregs in skin-draining lymph nodes (LNs).Key messagesACC1 deficiency in T cells ameliorates psoriatic skin inflammation in mice.ACC1 deficiency in T cells reduces IL-17A-producing Th17/Tc17/dysfunctional Treg populations in psoriatic lesions.ACC1 deficiency in T cells restrains IFN-γ-producing Th1/Tc1 populations in psoriatic skin lesions and skin-draining LNs.ACC1 deficiency promotes activated CD44+CD25+ Tregs and effector CD62L-CD44+ Tregs under homeostasis and psoriatic conditions.

Adenosine Triphosphate Citrate Lyase and Fatty Acid Synthesis Inhibition

Adenosine triphosphate citrate lyase (ACLY) is a key regulatory enzyme of glucose metabolism, cholesterol and fatty acid synthesis, and the inflammatory cascade. Bempedoic acid, an ACLY inhibitor, significantly reduces atherogenic lipid markers, including low-density lipoprotein cholesterol (LDL-C), non-high-density lipoprotein cholesterol, and apolipoprotein B. Additional effects of ACLY inhibition include antitumor growth; reduction of triglycerides and proinflammatory molecules such as high-sensitivity C-reactive protein; less insulin resistance; reduction of hepatic lipogenesis; and weight loss. While numerous ACLY inhibitors have been identified, most of the clinical data have focused on bempedoic acid. The Cholesterol Lowering via Bempedoic Acid, an ACL-Inhibiting Regimen (CLEAR) program was a series of phase 3 clinical trials that evaluated its effects on lipid parameters and safety, leading to US Food and Drug Administration approval in 2020. CLEAR Outcomes was a phase 3, double-blind, randomized, placebo-controlled trial in individuals with a history of statin intolerance, serum LDL-C level of 100 mg/dL or higher, and a history of, or at high risk for, cardiovascular disease. Bempedoic acid modestly reduced the primary 4-way cardiovascular composite end point as well as the individual components of myocardial infarction and coronary revascularization but did not reduce stroke, cardiovascular death, or all-cause mortality. Rates of gout and cholelithiasis were higher with bempedoic acid, and small increases in serum creatinine, uric acid, and hepatic-enzyme levels were also observed. ACLY inhibition with bempedoic acid has been established as a safe and effective therapy in high-risk patients who require further LDL-C lowering, particularly for those with a history of statin intolerance. The recently published CLEAR Outcomes trial revealed modest reductions in cardiovascular events with bempedoic acid, proportional to its LDL-C lowering, in high-risk individuals with statin intolerance and LDL-C levels of 100 mg/dL or higher. The additional effects of ACLY inhibition have prompted a more thorough search for novel ACLY inhibitors for conditions such as cancer, hypertriglyceridemia, chronic inflammation, type 2 diabetes, fatty liver disease, obesity, and metabolic syndrome. Similarly, therapies that reduce fatty acid synthesis are being explored for their use in cardiometabolic conditions.

Plasmodium berghei oocysts possess fatty acid synthesis and scavenging routes

Malaria parasites carry out fatty acid synthesis (FAS) in their apicoplast organelle via a bacterially related (type II) enzymatic pathway. In the vertebrate host, exoerythrocytic Plasmodium stages rely on FAS, whereas intraerythrocytic stages depend on scavenging FA from their environment. In the mosquito, P. falciparum oocysts express and rely on FAS enzymes for sporozoite formation, but P. yoelii oocysts do not express, nor depend on, FAS enzymes and thus rely on FA scavenging to support sporogony. In P. berghei, FAS enzymes are similarly expendable for sporogony, indicating it conforms to the P. yoelii scenario. We show here that P. berghei, unexpectedly, expresses FAS enzymes throughout oocyst development. These findings indicate that P. berghei can employ FAS alongside FA scavenging to maximise sporogony and transmission, and is more similar to P. falciparum than previously assumed with respect to FA acquisition by the oocyst. The ability of oocysts to switch between FAS and scavenging could be an important factor in the non-competitive relationship of resource exploitation between Plasmodium parasites and their mosquito vectors, which shapes parasite virulence both in the insect and vertebrate.

P-543 Higher maternal age alters the insulin/IGF system and intracellular lipid metabolism of the endometrium and in the preimplantation embryo – insights from the rabbit model.

Abstract Study question Our aim was to analyse the embryo-maternal-interaction, focusing on the insulin/IGF-system and lipid metabolism on day 6 of pregnancy in reproductive young and old rabbits. Summary answer Advanced maternal age has a decisive effect on maternal and embryonic insulin/IGF-signalling and lipid metabolism, leading to higher embryo loss already during preimplantation period. What is known already The reproductive potential in women declines with age. Molecular and biochemical mechanisms involved in age-related infertility and their impact on embryo-maternal-interaction during early pregnancy are still not completely understood. However, establishment of a successful pregnancy depends on the physiological condition of the mother and a continuous dialogue with the developing embryo. The insulin/IGF-system plays a pivotal role in this embryo-maternal crosstalk, connecting maternal insulin/IGF with embryonic metabolism, cell proliferation and differentiation. Study design, size, duration We used the rabbit as reproductive model to investigate maternal age-related alterations in embryo-maternal-interaction during preimplantation period. Compared to humans, the rabbit shares high similarities in early embryo development, gastrulation and lipid metabolism (DOI: 10.1530/REP-12-0091 and DOI: 10.1093/ajcn/62.2.458S). A total of 50 young (16-20 weeks) and 31 old (&amp;lt;108 weeks) sexually mature, female rabbits were used for analysis at day 6 post coitum. Participants/materials, setting, methods We measured mRNA and protein levels of target genes of the insulin/IGF system and lipid metabolism by quantitative PCR, Western Blot and ELISA. Therefore, maternal blood, endometrium and blastocysts were analysed from reproductive young (16 to 20 weeks) and old (over 108 weeks) rabbits on day 6 of pregnancy. Blastocysts and ovulation points were counted and only blastocysts at the pre-gastrulating stage 1, separated in embryoblast (EB) and trophoblast (TB), were used for further analyses. Main results and the role of chance At day 6 of pregnancy, reproductive old rabbits had a lower amount of embryos. Maternal serum insulin and IGF levels were reduced in reproductive old rabbits, accompanied by a paracrine upregulation of IGF1 and its receptors in the endometrium. Preimplantation blastocysts adapted to hormonal changes by reducing IGF1 and IGF2 levels in both embryonic compartments, EB and TB, while the expression of embryonic IGF receptors was unchanged. Furthermore, an increase of fatty acids metabolism was observed in the ageing endometrium, indicated by the higher level of carnitine palmitoyltransferase I B (CPT1B) and elevated expression of fatty acid binding and transport proteins. These results are in line with lower level of fatty acid synthesis (FASN) in the endometrium from old, gravid rabbits, the key enzyme of fatty acid synthesis. Embryonic fatty acid uptake and b-oxidation were increased in EB and TB, too. The observed changes in embryonic and maternal lipid metabolism are caused by the alterations of the transcription factors cAMP-responsive element binding protein (CREB) and peroxisome proliferator-activated receptor (PPAR) α and γ in endometrium and embryos from reproductive old rabbits. Limitations, reasons for caution Rabbit embryogenesis reflects human development only during blastocysts formation. Therefore, statements are limited to the embryogenesis stages investigated. Wider implications of the findings The results of the current study are in accordance with the common literature, showing that advanced maternal age affects developmental competence of embryos. Our study points out that advanced maternal age alters lipid metabolism and insulin/IGF-signalling, which are two crucial components in embryo-maternal-interaction. Trial registration number not applicable

Effects of Melatonin Supplementation on Lipid Metabolism and Body Fat Accumulation in Ovariectomized Rats.

Postmenopausal obesity is a rising problem. Melatonin (Mel) is a hormone secreted by the pineal gland that regulates the circadian rhythms and improves obesity. In this experiment, ovariectomized (OVX) rats were used as a menopause model to explore the effects of Mel supplementation on lipid metabolism, body fat accumulation, and obesity. Nine-week-old female rats underwent an OVX surgery and were assigned to the following groups: control group (C), low-dose group (L, 10 mg/kg body weight (BW) Mel), medium-dose group (M, 20 mg/kg BW Mel), and high-dose group (H, 50 mg/kg BW Mel), administered by gavage for 8 weeks. The results showed that the OVX rats supplemented with low, medium, and high doses of Mel for 8 weeks exhibited reduced BW gain, perirenal fat mass, and gonads fat mass, and an increased serum irisin level. Low and high doses of Mel induced brite/beige adipocytes in the white adipose tissues. In addition, the messenger RNA levels of the fatty acid synthesis enzymes were significantly reduced after the high-dose Mel supplementation. Thus, Mel can reduce the hepatic fatty acid synthesis and promote the browning of white adipose tissues through irisin; thereby, improving obesity and body fat accumulation in OVX rats.

Research Progress of Serum VEGF and FAS in Prognosis of Gastric Cancer

Vascular endothelial growth factor (VEGF) is an important factor to promote endothelial cell division and angiogenesis. In physiological conditions, the expression level of VEGF in human tissues is very low. Ischemia, hypoxia and many tumors can promote the synthesis and secretion of VEGF, and its expression level is related to the degree of vascularization of tumors, the proliferation, growth and metastasis of tumor cells. Fatty acid synthase (FAS) is a key enzyme for endogenous fatty acid synthesis, which is expressed at a low level in normal tissue cells, while FASN in a variety of tumor cells is continuously highly expressed to meet the energy needs of cell proliferation and the excessive demand for rapid proliferation of tumor cells to form cell membrane lipids. A large amount of research shows that VEGF and FAS play an important role in the development and development of many tumors, and the abnormally high expression in tumor tissue cells is positively correlated with serum VEGF and FAS levels, which is closely related to the prognosis of tumors. Gastric cancer (GC) is one of the most common clinical malignant tumors of the digestive tract, and its incidence and mortality have shown an increasing trend in recent years, and the prognosis is poor, seriously endangering human health. The biological properties of GC are related to the level of VEGF and FAS expression in tissues and serum. This article reviews the research progress of VEGF and FAS, their expression in GC and their prognosis.

Abstract 595: Targeting metabolic vulnerability in brain-metastatic HER2+ breast cancer

Abstract Introduction: Human epidermal growth factor receptor 2 positive (HER2+) breast cancer tumors have increased risk of brain metastases at an advanced stage. The brain’s microenvironment is relatively low in lipids; therefore, breast cancer cells that colonize the brain have an increased expression of fatty acid synthesis enzymes. This presents a potential vulnerability that could be targeted. There is an established feed-forward relationship between HER2 and fatty acid synthase (FASN) where HER2 signaling activates FASN signaling. FASN inhibition has been shown to decrease cell invasion in a preclinical breast cancer model. We hypothesize that targeting HER2+ breast cancer cells with a HER2 tyrosine kinase inhibitor (TKI) or HER2 antibody-drug conjugate (ADC) in combination with a FASN inhibitor will lead to synergistic cell death. We also hypothesize that FASN inhibitors alone impede outgrowth and invasion of HER2+ breast cancer cells. Methods: We performed combinatorial drug-screening using the Chou-Talalay method in vitro using HER2+ breast cancer cell spheroids and tested the impact of FASN inhibitors alone on the outgrowth of these spheroids embedded in Matrigel. The HER2+ cell lines we used include JIMT-1, JIMT-1-BR3, SUM190, and SUM-190-BR3. JIMT-1-BR3 and SUM190-BR3 are brain-seeking subclones of the primary cell lines generated by serial passaging through mice with collection of cells in the brain. In combinatorial drug-screening, we calculated combination index (CI) values for the combination of each of two FASN inhibitors (TVB-2640 and BI-99179) with each of three clinically approved HER2 TKIs (Tucatinib, Lapatinib, and Neratinib) and each of two ADCs (Trastuzumab deruxtecan and Trastuzumab emtansine). The experiments were performed in both media supplied with fetal bovine serum (FBS) and with lipid-stripped FBS, to mimic the brain microenvironment. Results: Drug screening revealed that FASN inhibitors are toxic only at high doses in cell viability assays. However, we calculated combination index (CI) values using the Chou-Talalay method indicative of synergy for the combinations of the FASN inhibitors with the HER2-targeting drugs. Moreover, we discovered that the FASN inhibitors TVB-2640 and BI-99179 alone significantly impede the outgrowth of the spheroids embedded in Matrigel. Conclusions: Based on these promising preliminary data, we will evaluate these results in vivo. Breast cancer patients harboring brain metastases are difficult to treat, and they suffer from severe symptoms impacting daily life and have poor survival rates. Our ultimate goal is to launch a clinical trial to test one or more of these drug combinations to provide an additional therapeutic option that may improve patients’ lives and decrease mortality. Citation Format: Habib Serhan, Liwei Bao, Xu Cheng, Sofia Merajver, Aki Morikawa, Nathan Merrill. Targeting metabolic vulnerability in brain-metastatic HER2+ breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 595.

Ginger polysaccharide promotes myeloid-derived suppressor cell apoptosis by regulating lipid metabolism.

Recently, targeting myeloid-derived suppressor cells (MDSCs) which mainly play an immunosuppressive role in tumor microenvironment has become a hot spot in tumor immunotherapy. This study focuses on biological effect of ginger polysaccharide extracted from natural plants on promoting apoptosis of MDSCs by regulating lipid metabolism. An MTT assay was used to detect the inhibitory effect of ginger polysaccharide on the growth of an MDSC-like cell line (MSC-2). The apoptosis-promoting effect of ginger polysaccharide on MSC-2 cells was detected by flow cytometry. Expression levels of apoptosis proteins (caspase 9 and Bcl-2) and lipid metabolism enzymes (fatty acid synthase (FASN) and diacylglycerol acyltransferase 2) in MSC-2 cells treated with different concentrations of ginger polysaccharide were detected by western blot assay. Nile red staining was used to quantitatively detect the effect of ginger polysaccharide on lipid droplet synthesis. Ginger polysaccharide inhibited proliferation of MSC-2 cells and promoted their apoptosis by upregulating pro-apoptotic caspase 9 protein, downregulating anti-apoptotic Bcl-2 protein, inhibiting expression of FASN and diacylglycerol acyltransferase 2 (key enzymes in fatty acid synthesis and lipid droplet formation, respectively). Ginger polysaccharide promoted apoptosis of MDSCs by regulating key lipid metabolism enzymes, inhibiting fatty acid synthesis and lipid droplet accumulation, and reducing the energy supply of cells.

P019 Host-Enterobacteriaceae interactions and mitochondrial dysfunction in Crohn’s colitis

Abstract Background Crohn’s disease (CD) is characterized by chronic gastrointestinal inflammation and unfavourable changes in the composition of intestinal microbiota (‘dysbiosis’). Members of Enterobacteriaceae such as K. pneumoniae and E. coli are often over-represented in colonic mucosa of CD patients. These bacteria contribute to vicious circle of dysbiosis and inflammation by expressing multiple virulence factors. Further, mitochondrial dysfunction in Paneth cells has recently been reported in ileal CD. In agreement, high-fat diet and repeated use of antibiotics increases susceptibility to colitis by damaging mitochondria. However, it remains unknown whether impaired mitochondrial bioenergetics could enhance mucosal colonization by Enterobacteriaceae and thus, contribute to the pathophysiology of colonic CD. Furthermore, the molecular mechanism leading to mitochondrial damage in colonic CD are incompletely understood. Methods Right colonic biopsies were collected from 74 adult CD patients and 28 healthy participants at St. Paul’s Hospital (Vancouver, BC, Canada). Microbes in colonic biopsies were characterized by 16S rDNA sequencing using Illumina MiSeq platform, followed by analysis of differentially abundant families via ANCOM-BC methodology. Further, high-throughput data-independent acquisition (DIA) proteomics was performed in colonic biopsies (Bruker Daltonics TimsTof Pro2 LC-MS/MS), and later analyzed via DIA-neural network software. Spearman's rank correlation approach was used for host proteomics- Enterobacteriaceae correlational analysis. Microbiome and proteomic data were corrected for false discovery rate (FDR; &amp;lt; 0.5 for statistical significance). For validation studies, human colonic TC7 epithelial cells and patient-derived organoid cultures were infected with CD-patient derived E. coli ± C75, a chemical inhibitor of fatty acid synthase (FASN; de novo fatty acid synthesis enzyme). Results We found an increased abundance of Enterobacteriaceae members in colonic mucosa of CD patients compared to healthy controls (Fig A). Next, our proteomics data revealed a significant downregulation in a group of proteins which were functionally related to mitochondrial health and activity, in CD patients compared to controls (Fig B). Further, Spearman’s analysis showed a positive correlation between Enterobacteriaceae and host FASN enzyme (Fig C), a protein directly related to mitochondrial metabolism. Interestingly, we found that blocking FASN with chemical inhibitor (C75) significantly enhanced colonization by E. coli in TC7 cells (Fig D). Conclusion Mechanistically, our study reports that aberrant activity of host FASN enzyme may cause mitochondrial dysfunction and thus, facilitates intestinal colonization by Enterobacteriaceae in CD patients.