Accumulation Of Saturated Fatty Acids Research Articles

IL-33 Reduces Saturated Fatty Acid Accumulation in Mouse Atherosclerotic Foci.

The cellular and molecular mechanisms of atherosclerosis are still unclear. Type 2 innate lymphocytes (ILC2) exhibit anti-inflammatory properties and protect against atherosclerosis. This study aimed to elucidate the pathogenesis of atherosclerosis development using atherosclerosis model mice (ApoE KO mice) and mice deficient in IL-33 receptor ST2 (ApoEST2 DKO mice). Sixteen-week-old male ApoE KO and ApoEST2 DKO mice were subjected to an 8-week regimen of a high-fat, high-sucrose diet. Atherosclerotic foci were assessed histologically at the aortic valve ring. Chronic inflammation was assessed using flow cytometry and real-time polymerase chain reaction. In addition, saturated fatty acids (palmitic acid) and IL-33 were administered to human aortic endothelial cells (HAECs) to assess fatty acid metabolism. ApoEST2 DKO mice with attenuated ILC2 had significantly worse atherosclerosis than ApoE KO mice. The levels of saturated fatty acids, including palmitic acid, were significantly elevated in the arteries and serum of ApoEST2 DKO mice. Furthermore, on treating HAECs with saturated fatty acids with or without IL-33, the Oil Red O staining area significantly decreased in the IL-33-treated group compared to that in the non-treated group. IL-33 potentially prevented the accumulation of saturated fatty acids within atherosclerotic foci.

38-OR: Insulin Prevents Palmitate-Induced Stress Kinase Activation, Autophagy, and Apoptosis in Human Cardiac Progenitor Cells

Abnormal accumulation of saturated fatty acids in the heart results in insulin resistance, stress kinase activation, and increased cardiovascular risk in humans. The viability of human cardiac progenitor cells (CPC) is essential for myocardium homeostasis. This study investigates the ability of palmitate, a saturated fatty acid, to induce apoptosis, autophagy, and stress kinase activation in human CPC isolated from right auricle biopsies of nondiabetic, non-obese subjects, and the potential protective effects of insulin on palmitate-induced abnormalities. Human CPC expressed both IR-A and IR-B, and IR-A was more expressed than IR-B, as assessed by quantitative RT-PCR and immunoblotting. Exposure of human CPC to 100 nM insulin for 15 minutes resulted in increased Akt (S473) and p44/p42 MAPK (T202/Y204) phosphorylation (p<0.05), as evidenced by immunoblotting. Treatment of human CPC with palmitate 0.25 mM for 16 h induced apoptosis (p<0.05), as assessed by caspase-3 cleavage and ELISA assay, and increased S63-phosphorylation of c-Jun (p<0.05), a downstream transcription factor of JNK 1/2, as assessed by immunoblotting. Exposure of human CPC to 0.25 mM palmitate for 16 h resulted also in increased autophagy, evidenced by light chain 3-II immunoblotting (p<0.05). Pretreatment with 20 µM SP600125, a JNK inhibitor, for 1 h inhibited palmitate-induced apoptosis (p<0.05), but not autophagy. Similarly, pretreatment with 10 mM 3-methyladenine, an autophagy inhibitor, for 1 h decreased palmitate-induced apoptosis (p<0.05). Interestingly, palmitate effects on apoptosis, autophagy, and on stress kinase activation, were prevented when human CPC were pretreated with 100 nM insulin for 1 h (p<0.05). In conclusion, insulin prevents palmitate-induced apoptosis by inhibition of JNK signaling and autophagy in human CPC. Hence, preserving insulin signaling in human CPC might protect from lipotoxicity-induced metabolic alterations in the heart. Disclosure I. Calderoni: None. R. Doria: None. C. Caccioppoli: None. V. Genchi: None. G. Palma: None. G. Santarpino: None. A.D. Milano: None. A. Leonardini: None. A. Natalicchio: Other Relationship; AstraZeneca, Novo Nordisk, Sanofi, Boehringer-Ingelheim, Lilly. S. Perrini: None. A. Cignarelli: Speaker's Bureau; Eli Lilly and Company, Novo Nordisk, Sanofi. F. Giorgino: Research Support; Lilly, Roche Diabetes Care. Consultant; Novo Nordisk, Lilly. Speaker's Bureau; Abbott, Boehringer-Ingelheim, Lilly. Advisory Panel; Boehringer-Ingelheim, Amarin Corporation, Medtronic, Roche Diabetes Care, Sanofi. Speaker's Bureau; Sanofi. Advisory Panel; Bayer Inc., Novo Nordisk. Research Support; AlfaSigma. Speaker's Bureau; Medscape. L. Laviola: Speaker's Bureau; Abbott. Advisory Panel; A. Menarini Diagnostics, Boehringer Ingelheim Inc., Eli Lilly and Company, Novo Nordisk, Roche Diabetes Care. Speaker's Bureau; Terumo Corporation. Other Relationship; Medtronic. Advisory Panel; Sanofi.

Disrupted Lipid Homeostasis and Loss of IRF4 Impairs B-Cell and Plasma Cell Development in a Murine Model of Accelerated Aging

The aging immune system is characterized by increased bone marrow (BM) adiposity, myeloid skewing, impaired lymphocyte maturation, and loss of hematopoietic stem and progenitor cell (HSPC) regenerative capacity. Human systemic aging studies have found alterations in lipid and fatty acid metabolism, such as increased saturated fatty acid accumulation and decays in n-3 polyunsaturated fatty acid (PUFA) species leading to cellular membrane rigidity. However, the extent to which impaired fatty acid metabolism contributes to immune system aging and HSPC development is largely unexplored. In this study, we performed multi-omics studies to characterize BM aging phenotypes in a recently described mouse model that exhibits signs of accelerating aging in brain and eye tissues. This robust aging model expresses a mutant inactive form of the very long chain (VLC) PUFA elongation enzyme, Elongation of very long chain fatty acids protein 2 (ELOVL2), which is responsible for the elongation of 22-carbon PUFAs to 24-carbon PUFAs. These VLC-PUFAs are synthesized in vivo and are not readily available through dietary means. Previous studies using this mouse model demonstrated that Elovl2 DNA methylation-dependent and mutation-associated loss of function is a key driver of age-related defects in eye and brain tissues, however the hematopoietic system has not been characterized to date in this model. To investigate the extent to which impaired VLC-PUFA production in the setting of ELOVL2 enzymatic deficiency might also accelerate blood stem cell aging phenotypes, multi-omics studies were performed in murine BM samples from young (3 months old) and aged (18 months old) wild-type mice, compared with age-matched Elovl2 mutant mice. Total BM samples were subjected to lipidomics analyses, whole transcriptome RNA-sequencing (RNA-seq), and ATAC-seq analyses. Lipidomic profiling showed an almost complete depletion of direct and secondary products of ELOVL2 in BM isolated from mutant animals, suggesting significant changes in the biophysical properties of membranes in the cells. Gene set enrichment analyses (Reactome) of RNA-seq data revealed that pathways involving B cell receptor (BCR) signalling and immunoregulatory interactions between lymphoid and non-lymphoid cells were among the most differentially regulated in Elovl2 mutant mouse BM compared to age-matched controls. Key lymphoid lineage maturation markers (Cd19, Cd22, and Slamf7, among others) were downregulated in the BM of aged wild-type mice, and to a greater extent in Elovl2 mutant animals. This was accompanied by a significant downregulation of the lymphoid and plasma cell transcription factor, interferon-regulatory factor-4 (Irf4), in aged and Elovl2 mutant groups compared with young mice. In addition, phenotypic analyses of B cell lineage marker protein expression were performed by flow cytometry to confirm depletion of lymphoid cell populations and Irf4 expression in this model. Finally, ATAC-seq data revealed changes in DNA accessibility related to Elovl2 mutation, suggesting significant epigenetic changes in nuclear programs. These findings suggest that Elovl2 loss of function in a murine model of accelerated aging promotes diverse lipidomic, transcriptomic and chromatin alterations targeting lymphoid populations in murine BM, which may be mechanistically driven by a downregulation of Irf4. Together, these results provide insights into a functional link between disrupted lipid homeostasis and aging-related defects in lymphocyte maturation typified by loss of B-cell and plasma cell populations. Together, modulation of lipid catabolism pathways may provide a novel avenue for reversing a variety of age-related immune deficits including enhanced susceptibility to infection.

Dynamic Change of Carbon and Nitrogen Sources in Colonized Apples by Penicillium expansum.

Penicillium expansum is a necrotrophic pathogen, which actively kills host cells and obtains nutrients from dead cells to achieve infection. However, few reports have elucidated the differential levels of carbon and nitrogen sources over increasing distances of the leading edge in fungal colonized fruit tissues during colonization. Our results showed that the highest consumption of sucrose and fructose, as well as the accumulation of glucose, were found in the decayed region of P. expansum-colonized 'Delicious' apple fruit compared with the healthy region at the leading edge and the healthy region 6 mm away from the leading edge. As nitrogen sources, the contents of methionine, glutamate, leucine, valine, isoleucine and serine were the lowest in the decayed region compared with the healthy regions during colonization. In addition, the titratable acidity, oxalic acid, citric acid, succinic acid and malic acid showed the highest accumulation in the decayed region compared with the healthy regions. P. expansum colonization induced the accumulation of saturated fatty acids in the decayed region, while the level of unsaturated fatty acids was the lowest. These changes were not observed in the healthy regions. These results indicated that P. expansum kills cells in advance of its colonization in order to obtain the nutrients of the apple tissue from the distal leading tissue of the colonized apple. It is understood that more carbon and nitrogen sources are required for fungal colonization, and a stronger defense response against colonization occurred in the fruit, causing the transit of nutrients from the distal tissue to the infected sites.

Identification and Functional Characterization of Acyl-ACP Thioesterases B (GhFatBs) Responsible for Palmitic Acid Accumulation in Cotton Seeds.

In spite of increasing use in the food industry, high relative levels of palmitic acid (C16:0) in cottonseed oil imposes harmful effects on human health when overconsumed in the diet. The limited understanding of the mechanism in controlling fatty acid composition has become a significant obstacle for breeding novel cotton varieties with high-quality oil. Fatty acyl-acyl carrier protein (ACP) thioesterase B (FatBs) are a group of enzymes which prefer to hydrolyze the thioester bond from saturated acyl-ACPs, thus playing key roles in controlling the accumulation of saturated fatty acids. However, FatB members and their roles in cotton are largely unknown. In this study, a genome-wide characterization of FatB members was performed in allotetraploid upland cotton, aiming to explore the GhFatBs responsible for high accumulations of C16:0 in cotton seeds. A total of 14 GhFatB genes with uneven distribution on chromosomes were identified from an upland cotton genome and grouped into seven subfamilies through phylogenetic analysis. The six key amino acid residues (Ala, Trys, Ile, Met, Arg and Try) responsible for substrate preference were identified in the N-terminal acyl binding pocket of GhFatBs. RNA-seq and qRT-PCR analysis revealed that the expression profiles of GhFatB genes varied in multiple cotton tissues, with eight GhFatBs (GhA/D-FatB3, GhA/D-FatB4, GhA/D-FatB5, and GhA/D-FatB7) having high expression levels in developing seeds. In particular, expression patterns of GhA-FatB3 and GhD-FatB4 were positively correlated with the dynamic accumulation of C16:0 during cotton seed development. Furthermore, heterologous overexpression assay of either GhA-FatB3 or GhD-FatB4 demonstrated that these two GhFatBs had a high substrate preference to 16:0-ACP, thus contributing greatly to the enrichment of palmitic acid in the tested tissues. Taken together, these findings increase our understanding on fatty acid accumulation and regulation mechanisms in plant seeds. GhFatBs, especially GhA-FatB3 and GhD-FatB4, could be molecular targets for genetic modification to reduce palmitic acid content or to optimize fatty acid profiles in cotton and other oil crops required for the sustainable production of healthy edible oil.

Brazilian green propolis improves gut microbiota dysbiosis and protects against sarcopenic obesity.

Brazilian green propolis is an important honeybee product that is considered beneficial for health. Here, we examined the therapeutic potential of dietary supplementation with propolis against sarcopenic obesity using Db/Db mice. Db/m mice fed a normal diet alone and Db/Db mice fed normal diet alone, or supplemented with different amounts of propolis (0.08, 0.4 and 2%), were examined for effects on sarcopenic obesity. Propolis improved the glucose tolerance (P<0.001), increased the grip strength (P<0.001) and the weight of soleus (P=0.006) and plantaris muscles (P=0.008). Moreover, propolis improved the non-alcoholic fatty liver disease activity score (P<0.001) and decreased the expression of genes related to inflammation, liver fibrosis and fatty acid metabolism. Propolis decreased the accumulation of saturated fatty acids in the liver and increased their excretion in faeces. With regard to the innate immunity, propolis decreased the ratio of M1 macrophages (P=0.008) and Type 1 and 3 innate lymphoid cells to CD45-positive cells (P<0.001) and increased the ratio of M2 macrophages (P=0.002) and ILC2s (P=0.007) in the liver. Additionally, propolis decreased the expression of genes related to muscle atrophy and inflammation and the concentration of saturated fatty acids in the soleus muscle. 16S rRNA phylogenetic sequencing revealed that propolis increased the Bacteroidetes/Firmicutes ratio, and the abundance of Butyricicoccus and Acetivibrio genera. Gut microbiota related to the pentose phosphatase pathway and glycerolipid metabolism was more prevalent after the administration of propolis. This is the first study to demonstrate that propolis can improve sarcopenic obesity by improving dysbiosis due to overeating and provides new insights into diet-microbiota interactions during sarcopenic obesity.

GBM tumors are heterogeneous in their fatty acid metabolism and modulating fatty acid metabolism sensitizes cancer cells derived from recurring GBM tumors to temozolomide.

Glioblastoma is a highly lethal grade of astrocytoma with very low median survival. Despite extensive efforts, there is still a lack of alternatives that might improve these prospects. We uncovered that the chemotherapeutic agent temozolomide impinges on fatty acid synthesis and desaturation in newly diagnosed glioblastoma. This response is, however, blunted in recurring glioblastoma from the same patient. Further, we describe that disrupting cellular fatty acid homeostasis in favor of accumulation of saturated fatty acids such as palmitate synergizes with temozolomide treatment. Pharmacological inhibition of SCD and/or FADS2 allows palmitate accumulation and thus greatly augments temozolomide efficacy. This effect was independent of common GBM prognostic factors and was effective against cancer cells from recurring glioblastoma. In summary, we provide evidence that intracellular accumulation of saturated fatty acids in conjunction with temozolomide based chemotherapy induces death in glioblastoma cells derived from patients.

Empagliflozin-Enhanced Antioxidant Defense Attenuates Lipotoxicity and Protects Hepatocytes by Promoting FoxO3a- and Nrf2-Mediated Nuclear Translocation via the CAMKK2/AMPK Pathway.

Lipotoxicity is an important factor in the development and progression of nonalcoholic steatohepatitis. Excessive accumulation of saturated fatty acids can increase the substrates of the mitochondrial electron transport chain in hepatocytes and cause the generation of reactive oxygen species, resulting in oxidative stress, mitochondrial dysfunction, loss of mitochondrial membrane potential, impaired triphosphate (ATP) production, and fracture and fragmentation of mitochondria, which ultimately leads to hepatocellular inflammatory injuries, apoptosis, and necrosis. In this study, we systematically investigated the effects and molecular mechanisms of empagliflozin on lipotoxicity in palmitic acid-treated LO2 cell lines. We found that empagliflozin protected hepatocytes and inhibited palmitic acid-induced lipotoxicity by reducing oxidative stress, improving mitochondrial functions, and attenuating apoptosis and inflammation responses. The mechanistic study indicated that empagliflozin significantly activated adenosine 5’-monophosphate (AMP)-activated protein kinase alpha (AMPKα) through Calcium/Calmodulin dependent protein kinase kinase beta (CAMKK2) instead of liver kinase B1 (LKB1) or TGF-beta activated kinase (TAK1). The activation of empagliflozin on AMPKα not only promoted FoxO3a phosphorylation and thus forkhead box O 3a (FoxO3a) nuclear translocation, but also promoted Nrf2 nuclear translocation. Furthermore, empagliflozin significantly upregulated the expressions of antioxidant enzymes superoxide dismutase (SOD) and HO-1. In addition, empagliflozin did not attenuate lipid accumulation at all. These results indicated that empagliflozin mitigated lipotoxicity in saturated fatty acid-induced hepatocytes, likely by promoting antioxidant defense instead of attenuating lipid accumulation through enhanced FoxO3a and Nrf2 nuclear translocation dependent on the CAMKK2/AMPKα pathway. The CAMKK2/AMPKα pathway might serve as a promising target in treatment of lipotoxicity in nonalcoholic steatohepatitis.

Interactive effects between salinity and nutrient deficiency on biomass production and bio-active compounds accumulation in the halophyte Crithmum maritimum

Plant bioactive metabolites play a pivotal role in protection against environmental stresses and offer great potential for nutraceutical exploitation. In this sense, halophytes present an exceptional opportunity for sustainable saline agriculture since they can massively accumulate bioactive metabolites under stressful conditions. We investigated the responses of the halophyte Crithmum maritimum to increasing salinity, nutrient deficient and their interaction. We hypothesized that the concentration of bioactive compounds would increase together with salinity and nutrient deficient, and that the interaction between these two stresses would produce synergic effects on bioactive compounds accumulation. We studied the tolerance and foliar accumulation of nutrients and bioactive compounds (amino acids, phenols, terpenes and fatty acids) for C. maritimum in response to salinity and nutrient deprivation in greenhouse controlled conditions. The high salinity tolerance of C. maritimum was not diminished by the interaction of salinity with nutrient limitation. Mineral nutrition deficit and saturated fatty acid accumulation were induced at 200–500 mM NaCl, and accumulation of polyphenol 5-caffeoylquinic acid and some amino acids were identified as nutrient deficiency markers. C. maritimum responded mainly to increasing salinity by reducing foliar accumulation of five terpenes and total lipids, and to nutrient limitation by increasing the concentration of vaccenic acid and 5-caffeoylquinic acid. The interaction between salinity and nutrient availability provoked antagonistic and synergistic effects on the accumulation of terpenes and fatty acids. C. maritimum showed high physiological phenotypic plasticity in the response to salt stress, nutrient deficiency and their combination.

Chronic exposure to low-dose cadmium facilitated nonalcoholic steatohepatitis in mice by suppressing fatty acid desaturation

Exposure to cadmium (Cd), a toxic metal, is epidemiologically linked to nonalcoholic steatohepatitis (NASH) in humans. However, the role of Cd in NASH remains to be fully elucidated. This study employed a novel murine NASH model to investigate the effects of chronic low-dose Cd on hepatic pathology and its underlying mechanisms. NASH is characterized by lipid accumulation, extensive cell death, and persistent inflammation in the liver. We found that treatment with Cd in drinking water (10 mg/L) for 6 or 12 weeks significantly boosted hepatic fat deposition, increased hepatocyte destruction, and amplified inflammatory responses in mice, confirming that low-dose Cd can facilitate NASH development in vivo. Mechanistically, chronic Cd exposure reshaped the hepatic transcriptional landscape, with PPAR-mediated fatty acid metabolic pathways being the most significantly altered. In particular, Cd repressed fatty acid desaturation, leading to the accumulation of saturated fatty acids whose lipotoxicity exacerbated cell death and, consequently, inflammatory activation. In summary, we validated the causal effects of chronic low-dose Cd on NASH in vivo and identified the fatty acid desaturation program as a novel target for Cd to instigate hepatopathological alterations.

LncRNA Tug1 maintains blood-testis barrier integrity by modulating Ccl2 expression in high-fat diet mice.

Sertoli cells are essential for spermatogenesis in the testicular seminiferous tubules by forming blood-testis barrier (BTB) and creating a unique microenvironment for spermatogenesis. Many lncRNAs have been reported to participate in spermatogenesis. However, the role of long noncoding RNAs (lncRNAs) in Sertoli cells has rarely been examined. Herein, we found that a high-fat diet (HFD) decreased sperm quality, impaired BTB integrity and resulted in accumulation of saturated fatty acids (SFAs), especially palmitic acid (PA), in mouse testes. PA decreased the expression of tight junction (TJ)-related proteins, increased permeability and decreased transepithelial electrical resistance (TER) in primary Sertoli cells and TM4 cells. Moreover, lncRNA Tug1 was found to be involved in PA-induced BTB disruption by RNA-seq. Tug1 depletion distinctly impaired the TJs of Sertoli cells and overexpression of Tug1 alleviated the disruption of BTB integrity induced by PA. Moreover, Ccl2 was found to be a downstream target of Tug1, and decreased TJ-related protein levels and TER and increased FITC-dextran permeability in vitro. Furthermore, the addition of Ccl2 damaged BTB integrity after overexpression of Tug1 in the presence of PA. Mechanistically, we found that Tug1 could directly bind to EZH2 and regulate H3K27me3 occupancy in the Ccl2 promoter region by RNA immunoprecipitation and chromatin immunoprecipitation assays. Our study revealed an important role of Tug1 in the BTB integrity of Sertoli cells and provided a new view of the role of lncRNAs in male infertility.

Cholesterol and saturated fatty acids synergistically promote the malignant progression of prostate cancer.

The excessive accumulation of saturated fatty acids and cholesterol have been linked to prostate cancer (Pca). Here, we found that lipoproteins, apolipoproteins, triglycerides and free fatty acids are significantly higher in the peripheral blood of prostate cancer patients than in non-cancer patients. Furthermore, the expression of ACC1, FASN and HMGCR is significantly higher in prostate cancer tissues than that in non-cancer tissues, and positively correlated with the gleason score. Using genetically engineered mouse models, we found that in a mouse model of high grade prostatic intraneoplasia (HGPIN), a combination of fatty acid synthase (FASN) overexpression and cholesterol efflux pump (Abca1) knockout resulted in the progression of prostatic intraneoplasia (PIN) to invasive PCa with 100% penetrance, as well as an increase in prostate cancer stem cell (PCSC)population, accompanied by activation of PGE2 and TGF-β signaling pathway. Our study suggests that the steady rise in prostate cancer incidence and mortality among Chinese population during the last several decades may be attribute to a combinational effect of fatty acid and cholesterol, and reduction in dietary fat and cholesterol intake could slow down the progression from occult lesions to prostate cancer.

Lipid metabolism dysfunction and toxicity of BDE-47 exposure in white adipose tissue revealed by the integration of lipidomics and metabolomics

2,2′,4,4′-Tetrabromodiphenyl ether (BDE-47) is one of the main and toxic congeners of polybrominated diphenyl ether (PBDE) family and considered to be associated with the development of obesity. However, little is known about its direct metabolic alterations on white adipose tissue (WAT). In this study, we evaluated the impacts of BDE-47 exposure on WAT dysfunctions in mice fed with low-fat diet (LFD) or high-fat diet (HFD) by the integration analysis of mass spectrometry-based metabolomics and lipidomics. The results showed that BDE-47 exposure together with HFD intervention induced adipocyte hypertrophy and accelerated the weight gain of WAT, whereas no obvious effects were observed in mice fed with LFD. The combination of BDE-47 and HFD induced intolerable levels of metabolites in purine and glutathione metabolism pathways, sufficient to increase oxidative stress in WAT. Importantly, continuous exposure of BDE-47 in HFD -fed mice caused lipid metabolism dysfunction by promoting fatty acid uptake and de novo synthesis and suppressing β-oxidation, ultimately leading to the accumulation of saturated fatty acids, triglycerides in WAT. At the same time, BDE-47 increased inflammatory infiltration into WAT, consequently promoting the productions of cytokines, TNFα and IL-6, in HFD fed mice. It is found that dysfunction of lipid metabolism and increasing inflammation led to lipotoxicity in WAT and severe obesity in HFD mice. Taken together, our findings deepen the understanding of the obesogenic effect of BDE-47 and help identify new potential strategies for clarifying the molecular and metabolic mechanisms.

Choline-deficient High-fat Diet-induced Steatohepatitis in BALB/c Mice

Background: Non-alcoholic steatohepatitis (NASH) is an expanding cause of chronic liver disease worldwide, including Indonesia, with higher risk progression to cirrhosis and hepatocellular carcinoma. Preclinical experiments using several mice models have been conducted to clarify its complex pathogenesis. This study was designed to investigate whether BALB/c mice on a choline-deficient high-fat diet can be used as a model for NASH. Materials and Methods: BALB/c male mice were fed choline-deficient L-amino acid-defined high-fat diet (CDAHFD) or a standard diet for six weeks. The body and liver weights, liver histology, and plasma biochemistry were analyzed. The relative expression levels of tumor necrosis factor (TNF)α, transforming growth factor (TGF)β1, collagen-1α1 (COL1α1), glutathione peroxidase 1 (GPx1), and uncoupling protein 2 (UCP2) genes in the livers were analyzed using a two-step real time-polymerase chain reaction. Liver fatty acids composition was analyzed using gas chromatography with flame ionization detector (GC-FID). Results: CDAHFD induced steatohepatitis in BALB/c mice with increased plasma levels of alanine aminotransferase. The liver of CDAHFD-fed BALB/c mice showed upregulated relative expression levels of TNFα, TGFβ1, COL1α1, GPx1, and UCP2 genes. The liver fatty acid analysis showed a significant accumulation of saturated fatty acids (SFAs) and an increased ratio of n-6/n-3 polyunsaturated fatty acids (PUFAs) in the livers of CDAHFD-fed BALB/c mice. Conclusion: This study suggests that CDAHFD can induce steatohepatitis in BALB/c mice and therefore may be used as NASH mice model.Keywords: steatohepatitis, fatty liver, choline-deficient high fat diet, BALB/c

Fatty acid desaturase activity in mature red blood cells and implications for blood storage quality.

Increases in the red blood cell (RBC) degree of fatty acid desaturation are reported in response to exercise, aging, or diseases associated with systemic oxidant stress. However, no studies have focused on the presence and activity of fatty acid desaturases (FADS) in the mature RBC. Steady state metabolomics and isotope-labeled tracing experiments, immunofluorescence approaches, and pharmacological interventions were used to determine the degree of fatty acid unsaturation, FADS activity as a function of storage, oxidant stress, and G6PD deficiency in human and mouse RBCs. In 250 blood units from the REDS III RBC Omics recalled donor population, we report a storage-dependent accumulation of free mono-, poly-(PUFAs), and highly unsaturated fatty acids (HUFAs), which occur at a faster rate than saturated fatty acid accumulation. Through a combination of immunofluorescence, pharmacological inhibition, tracing experiments with stable isotope-labeled fatty acids, and oxidant challenge with hydrogen peroxide, we demonstrate the presence and redox-sensitive activity of FADS2, FADS1, and FADS5 in the mature RBC. Increases in PUFAs and HUFAs in human and mouse RBCs correlate negatively with storage hemolysis and positively with posttransfusion recovery. Inhibition of these enzymes decreases accumulation of free PUFAs and HUFAs in stored RBCs, concomitant to increases in pyruvate/lactate ratios. Alterations of this ratio in G6PD deficient patients or units supplemented with pyruvate-rich rejuvenation solutions corresponded to decreased PUFA and HUFA accumulation. Fatty acid desaturases are present and active in mature RBCs. Their activity is sensitive to oxidant stress, storage duration, and alterations of the pyruvate/lactate ratio.

DDRE-05. STEAROYL COA DESATURASE IS ESSENTIAL FOR REGULATION OF ENDOPLASMIC RETICULUM HOMEOSTASIS AND TUMOR GROWTH IN GLIOBLASTOMA CANCER STEM CELLS

INTRODUCTIONEmerging evidence suggest that, in addition to glucose, fatty acids can also drive glioma growth. Increased lipid synthesis is one of the metabolic hallmarks of cancer, and indeed, unsaturated fatty acids (UFA) are particularly abundant in glioblastoma. However, the exact role of fatty acids in GBM tumors remains unclear. Blocking fatty acids synthesis can present a new therapy for GBM.METHODSThrough targeted inhibitors screening on glioma stem cells (GSCs), we found that they are highly susceptible to Stearoyl CoA Desaturase 1 (SCD1) inhibitors. SCD1 is a key enzyme responsible for the conversion of saturated fatty acids (SFA) to UFA. 1) Through cell-based assays and immunoblot analyses, we tried to understand the role of UFA, SFA and SCD1 in GSCs differentiation and proliferation. We investigated the mechanism between fatty acids and tumor growth through ER stress modulation linked with SCD1 expression. 2) As we found that GSCs are highly susceptible to SCD1 inhibition, we tested CAY, SCD1 inhibitor, in GSCs orthotopic mouse models and assess its effect on tumor growth and overall survival.RESULTSWe found that GSCs with extensive self-renewal capacity have an increased dependence on SCD1 activity. Through immunoblot analyses, we demonstrated that SCD1 inhibition exacerbates ER stress through accumulation of SFA and SCD1-mediated UFA synthesis mitigates ER stress. Survival analyses between SCD1 inhibitor-treated group and control group showed significant survival benefit in SCD1-inhibitor-treated group, in both mesenchymal (p=0.008, 35 days vs 18) and proneural (p=0.0002) type glioma cells (n=8/groups).CONCLUSIONSWe demonstrate that SCD1, the fatty acid desaturase, is essential for the maintenance of glioblastoma cancer stem cells. SCD1 is activated by ER stress and exerts a cytoprotective function by regulating ER homeostasis, thus favoring survival and tumor growth. Pharmacological targeting of SCD1 exhibits potent therapeutic efficacy in brain tumor mouse models.

LXRα activation and Raf inhibition trigger lethal lipotoxicity in liver cancer.

The success of molecular therapies targeting specific metabolic pathways in cancer is often limited by the plasticity and adaptability of metabolic networks. Here we show that pharmacologically induced lipotoxicity represents a promising therapeutic strategy for the treatment of hepatocellular carcinoma (HCC). LXRα-induced liponeogenesis and Raf-1 inhibition are synthetic lethal in HCC owing to a toxic accumulation of saturated fatty acids. Raf-1 was found to bind and activate SCD1, and conformation-changing DFG-out Raf inhibitors could disrupt this interaction, thereby blocking fatty acid desaturation and inducing lethal lipotoxicity. Studies in genetically engineered and nonalcoholic steatohepatitis-induced HCC mouse models and xenograft models of human HCC revealed that therapies comprising LXR agonists and Raf inhibitors were well tolerated and capable of overcoming therapy resistance in HCC. Conceptually, our study suggests pharmacologically induced lipotoxicity as a new mode for metabolic targeting of liver cancer.

Protective role of fat hen (Chenopodium album L.) extract and gamma irradiation treatments against fusarium root rot disease in sunflower plants.

One of the most drastic diseases causing economic losses in sunflower crops is fusarium root rot caused by Fusarium solani. Plant extracts and ionizing radiation provide alternative environmentally safe control agents that have a significant role in controlling and overcoming this fungal plant pathogen. In the present study, the effect of different concentrations of aqueous Chenopodium album extract (2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5 and 6.0%) and gamma radiation at a dose of 6Gy were examined for their efficacy in inducing resistance of sunflower plants against fusarium root rot caused by F. solani MG-3 by evaluation of some physiological and biochemical parameters of infected and healthy plants under greenhouse conditions. The pre-treatment of sunflower seeds with 6% C. album extract and 6Gy gamma radiation reduced fusarium incidence from 47.49% to 28.25%. Also, nucleic acid content, ascorbic acid, α-tocopherol, anthocyanin, total flavonoids, proline, glycine betaine and lipid components significantly increased in irradiated infected plants treated with C. album extract, while H2 O2 content and lipid peroxidation markedly decreased as compared with healthy control plants. Moreover, treatment with gamma radiation reduced the amount of unsaturated fatty acids through accumulation of saturated fatty acids compared with non-irradiated plants; treatment with C. album extract also enhanced the content of unsaturated fatty acids, with a noticeable decrease in saturated fatty acid content. Hence, C. album extract and gamma radiation can be used to enhance biological control of fusarium root rot of sunflower plants.

A brief period of darkness induces changes in fatty acid biosynthesis towards accumulation of saturated fatty acids in Chlorella vulgaris UMT-M1 at stationary growth phase.

The effects of a brief (3days) and prolonged (6days) period of incubation in darkness and light on the biomass content, lipid content and fatty acid profile in Chlorella vulgaris UMT-M1 were determined. Three days of incubation in darkness increased saturated fatty acid (SFA) content from 34.0 to 41.4% but decreased monounsaturated fatty acid (MUFA) content from 36.7 to 29.8%. Palmitic acid (C16:0) contentwas increased from 23.2 to 28.9%, whereas oleic acid (C18:1) contentwas reduced from 35.4 to 28.8%. Total oil content was slightly decreased from 20.4 to 18.7% after 3days of darkness, without a significant reduction in biomass compared to 3days of incubation in light. Biomass and oil content was highest in cultures incubated for 6days in light, however the stimulatory and inhibitory effects of darkness (or light) on SFA and MUFA content was no longer present at 6days of incubation. Findings from this study suggests that fatty acid composition in C. vulgaris could be modulated to favor either C16:0 or C18:1 by a brief period of either darkness or light incubation, prior to harvesting.

Copper-induced changes in growth, photosynthesis, antioxidative system activities and lipid metabolism of cilantro (Coriandrum sativum L.)

The present study aims to investigate the effect of copper (as CuSO4, 5H2O) supply (0, 25 and 50 μM) on performance of cilantro (Coriandrum sativum L.) plants grown under hydroponic conditions. All applied Cu concentrations drastically reduced the biomass production, length of the shoots and the roots and disturbed the ions (Cu, Ca, Fe, Zn and Mg) homeostasis. Either Cu-starvation (0 μM) or Cu-toxicity (25 and 50 μM) significantly reduced the net photosynthetic rate, stomatal conductance and transpiration rate resulting in reduced water use efficiency. Under Cu-toxicity, the variations in gas exchange parameters were associated with a remarkable decline in the photosynthetic pigments including Chlorophyll a, Chlorophyllb, Chlorophyll (a + b) and carotenoids. Additionally, an enhanced lipid peroxidation (evaluated as Malondialdehyde (MDA) contents) with a concomitant increase in proline, total soluble sugars and melanoidins contents were observed under these conditions. The increased MDA levels resulted in decrease in total lipid content and alteration of the fatty acid profiles in both shoots and roots with a general tendency toward the accumulation of saturated fatty acids that mirrors a decline in the desaturases activity. Although the increased activity of enzymatic antioxidants including catalase (CAT), gaiacol peroxidase (GPX) and ascorbate peroxidase (APX), the oxidative-induced injuries caused by 25 and 50 μM Cu were found to be irreversible and the optimal growth parameters were not achieved.