SCD1 mRNA Research Articles

Screening of fish oil fatty acids for antihyperlipidemic activity based on network pharmacology and validation of synergistic efficacy in vitro

Fish oil, rich in docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), shows promise as an anti-hyperlipidemic agent. We explored the synergistic lipid-lowering effects between long-chain monounsaturated fatty acids, EPA, and DHA using network pharmacology and experimental validation in HepG2 cells. Various fish oils, particularly Engraulis japonicus and Pacific saury, effectively reduced oleic acid-induced lipid accumulation. Network pharmacology identified 64 potential targets for fish oil fatty acids' synergistic anti-hyperlipidemic action. Validation revealed their superior impact on upregulating CPT1A and RXRA mRNA, promoting lipid metabolism, and suppressing SCD and FABP1 mRNA, inhibiting lipid synthesis. This combination also reduced IL6 expression, maintaining lipid homeostasis. Activating AMPK and PPAR pathways, it achieved lipid-lowering effects. These findings highlight the potential of fish oil fatty acids for anti-hyperlipidemic interventions, offering a novel research perspective.

IGF2BP3 enhances lipid metabolism in cervical cancer by upregulating the expression of SCD

Cervical cancer (CC) is the most common gynecologic malignancy, which seriously threatens the health of women. Lipid metabolism is necessary for tumor proliferation and metastasis. However, the molecular mechanism of the relationship between CC and lipid metabolism remains poorly defined. We revealed the expression of IGF2BP3 in CC exceeded adjacent tissues, and was positively associated with tumor stage using human CC tissue microarrays. The Cell Counting Kit-8, colony formation assay, 5-ethynyl-2′-deoxyuridine assay, transwell assays, wound-healing assays, and flow cytometry assessed the role of IGF2BP3 in proliferation and metastasis of CC cells. Besides, exploring the molecular mechanism participating in IGF2BP3-driven lipid metabolism used RNA-seq, which determined SCD as the target of IGF2BP3. Further, lipid droplets, cellular triglyceride (TG) contents, and fatty acids were accessed to discover that IGF2BP3 can enhance lipid metabolism in CC. Moreover, RIP assay and methylated RNA immunoprecipitation experiments seeked the aimed-gene-binding specificity. Lastly, the IGF2BP3 knockdown restrained CC growth and lipid metabolism, after which SCD overexpression rescued the influence in vitro and in vivo using nude mouse tumor-bearing model. Mechanistically, IGF2BP3 regulated SCD mRNA m6A modifications via IGF2BP3-METTL14 complex, thereby enhanced CC proliferation, metastasis, and lipid metabolism. Our study highlights IGF2BP3 plays a crucial role in CC progression and represents a therapeutic latent strategy. It is a potential tactic that blocks the metabolic pathway relevant to IGF2BP3 with the purpose of treating CC.

RNA sequencing unravels novel L cell constituents and mechanisms of GLP-1 secretion in human gastric bypass-operated intestine

Aims/hypothesisRoux-en-Y gastric bypass surgery (RYGB) frequently results in remission of type 2 diabetes as well as exaggerated secretion of glucagon-like peptide-1 (GLP-1). Here, we assessed RYGB-induced transcriptomic alterations in the small intestine and investigated how they were related to the regulation of GLP-1 production and secretion in vitro and in vivo.MethodsHuman jejunal samples taken perisurgically and 1 year post RYGB (n=13) were analysed by RNA-seq. Guided by bioinformatics analysis we targeted four genes involved in cholesterol biosynthesis, which we confirmed to be expressed in human L cells, for potential involvement in GLP-1 regulation using siRNAs in GLUTag and STC-1 cells. Gene expression analyses, GLP-1 secretion measurements, intracellular calcium imaging and RNA-seq were performed in vitro. OGTTs were performed in C57BL/6j and iScd1−/− mice and immunohistochemistry and gene expression analyses were performed ex vivo.ResultsGene Ontology (GO) analysis identified cholesterol biosynthesis as being most affected by RYGB. Silencing or chemical inhibition of stearoyl-CoA desaturase 1 (SCD1), a key enzyme in the synthesis of monounsaturated fatty acids, was found to reduce Gcg expression and secretion of GLP-1 by GLUTag and STC-1 cells. Scd1 knockdown also reduced intracellular Ca2+ signalling and membrane depolarisation. Furthermore, Scd1 mRNA expression was found to be regulated by NEFAs but not glucose. RNA-seq of SCD1 inhibitor-treated GLUTag cells identified altered expression of genes implicated in ATP generation and glycolysis. Finally, gene expression and immunohistochemical analysis of the jejunum of the intestine-specific Scd1 knockout mouse model, iScd1−/−, revealed a twofold higher L cell density and a twofold increase in Gcg mRNA expression.Conclusions/interpretationRYGB caused robust alterations in the jejunal transcriptome, with genes involved in cholesterol biosynthesis being most affected. Our data highlight SCD as an RYGB-regulated L cell constituent that regulates the production and secretion of GLP-1.Graphical

ADAR1-mediated RNA editing of SCD1 drives drug resistance and self-renewal in gastric cancer

Targetable drivers governing 5-fluorouracil and cisplatin (5FU + CDDP) resistance remain elusive due to the paucity of physiologically and therapeutically relevant models. Here, we establish 5FU + CDDP resistant intestinal subtype GC patient-derived organoid lines. JAK/STAT signaling and its downstream, adenosine deaminases acting on RNA 1 (ADAR1), are shown to be concomitantly upregulated in the resistant lines. ADAR1 confers chemoresistance and self-renewal in an RNA editing-dependent manner. WES coupled with RNA-seq identify enrichment of hyper-edited lipid metabolism genes in the resistant lines. Mechanistically, ADAR1-mediated A-to-I editing on 3’UTR of stearoyl-CoA desaturase (SCD1) increases binding of KH domain-containing, RNA-binding, signal transduction-associated 1 (KHDRBS1), thereby augmenting SCD1 mRNA stability. Consequently, SCD1 facilitates lipid droplet formation to alleviate chemotherapy-induced ER stress and enhances self-renewal through increasing β-catenin expression. Pharmacological inhibition of SCD1 abrogates chemoresistance and tumor-initiating cell frequency. Clinically, high proteomic level of ADAR1 and SCD1, or high SCD1 editing/ADAR1 mRNA signature score predicts a worse prognosis. Together, we unveil a potential target to circumvent chemoresistance.

Oleanolic Acid Inhibits SCD1 Gene Expression to Ameliorate Fructose-Induced Hepatosteatosis through SREBP1c-Dependent and -Independent Mechanisms.

The mechanisms of oleanolic acid (OA) regulating hepatic sterol regulatory element-binding protein (SREBP) 1c/stearoyl-CoA desaturase (SCD) 1 pathway to ameliorate fructose-induced hepatosteatosis are investigated. Rats treated with 10% w/v fructose solution are co-administered by OA for 5 weeks, and then sacrifice after fasting for 14 h. OA reverses the fructose-induced increase in hepatic triglyceride (TG) content and downregulates Scd1 mRNA expression. However, two upstream transcription factors, ChREBP and SREBP1c, remain at normal levels with or without fructose and/or OA. In vivo and in vitro studies using SREBP1c-/- mice and HepG2 cell models show that OA also inhibits SCD1 gene overexpression and high hepatic TG levels induced by fructose. On the other hand, in SCD1-/- mice, when the fructose diet is supplemented with high levels of oleic acid (OLA) to compensate for the deficiency of SCD1, OA inhibits hepatic SREBP1c and lipogenic gene expression and reduces hepatic OLA (C18:1) production to improve fructose and/or OLA induced liver lipid deposition. Furthermore, OA promotes PPARα and AMPK to enhance fatty acid oxidation in fructose + OLA-fed SCD1-/- mice. OA may inhibit SCD1 gene expression to ameliorate fructose-induced hepatosteatosis through SREBP1c-dependent and -independent mechanisms.

Anemoside B4 regulates fatty acid metabolism reprogramming in mice with colitis-associated cancer

The study aimed to investigate the effect of anemoside B4(B4) on fatty acid metabolism in mice with colitis-associated cancer(CAC). The CAC model was established by azoxymethane(AOM)/dextran sodium sulfate(DSS) in mice. Mice were randomly divided into a normal group, a model group, and low-, medium-, and high-dose anemoside B4 groups. After the experiment, the length of the mouse colon and the size of the tumor were measured, and the pathological alterations in the mouse colon were observed using hematoxylin-eosin(HE) staining. The slices of the colon tumor were obtained for spatial metabolome analysis to analyze the distribution of fatty acid metabolism-related substances in the tumor. The mRNA levels of SREBP-1, FAS, ACCα, SCD-1, PPARα, ACOX, UCP-2, and CPT-1 were determined by real-time quantitative PCR(RT-qPCR). The results revealed that the model group showed decreased body weight(P<0.05) and colon length(P<0.001), increased number of tumors, and increased pathological score(P<0.01). Spatial metabolome analysis revealed that the content of fatty acids and their derivatives, carnitine, and phospholipid in the colon tumor was increased. RT-qPCR results indicated that fatty acid de novo synthesis and β-oxidation-related genes, such as SREBP-1, FASN, ACCα, SCD-1, ACOX, UCP-2, and CPT-1 mRNA expression levels increased considerably(P<0.05, P<0.001). After anemoside B4 administration, the colon length increased(P<0.01), and the number of tumors decreased in the high-dose anemoside B4 group(P<0.05). Additionally, spatial metabolome analysis showed that anemoside B4 could decrease the content of fatty acids and their derivatives, carnitine, and phospholipids in colon tumors. Meanwhile, anemoside B4 could also down-regulate the expression of FASN, ACCα, SCD-1, PPARα, ACOX, UCP-2, and CPT-1 in the colon(P<0.05, P<0.01, P<0.001). The findings of this study show that anemoside B4 may inhibit CAC via regulating fatty acid metabolism reprogramming.

Abstract 1755: ADAR1-mediated RNA editing of SCD1 links lipid metabolism to gastric cancer drug resistance and self-renewal

Abstract Targetable drivers governing to 5-fluorouracil and cisplatin (5FU+CDDP) resistance remain elusive due to the paucity of physiologically and therapeutically relevant models. Accordingly, we established 5FU+CDDP resistant intestinal subtype GC patient-derived organoid lines. JAK/STAT signaling and its downstream, adenosine deaminases acting on RNA 1 (ADAR1), are shown to be concomitantly upregulated in the resistant lines. ADAR1 was demonstrated to confer chemoresistance and self-renewal in an RNA editing-dependent manner. WES-seq coupled with RNA-seq identified enrichment of hyperedited lipid metabolism genes in the resistant lines. Mechanistically, ADAR1-mediated A-to-I editing on 3’UTR of stearoyl-CoA desaturase (SCD1) increased binding of KH domain-containing, RNA-binding, signal transduction-associated 1 (KHDRBS1), thereby augmenting SCD1 mRNA stability. Consequently, SCD1 facilitates lipid droplet formation to alleviate chemotherapy-induced ER stress and enhances self-renewal through increasing β-catenin expression. Pharmacological inhibition of SCD1 abrogated chemoresistance and tumor-initiating cell frequency. Clinically, high proteomic level of ADAR1 and SCD1, or high SCD1 editing/ADAR1 mRNA signature score predicts a worse prognosis. Together, we unveiled a novel actionable target to circumvent chemoresistance. Citation Format: Jia Jian Loh, Tin Lok Wong, Shixun Lu, Helen HN Yan, Hoi Cheong Siu, Ren Xi, Dessy Chan, Max JF Kam, Lei Zhou, Man Tong, John A. Copland, Leilei Chen, Jingping Yun, Suet Yi Leung, Stephanie Ma. ADAR1-mediated RNA editing of SCD1 links lipid metabolism to gastric cancer drug resistance and self-renewal [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 1755.

Temporal-Regulation of Serum Lipids and Stearoyl CoA Desaturase and Lipoprotein Lipase mRNA in BALB/cHnn Mice

Databases for genes expressed in humans or cell cultures are being developed as a part of the Human Genome Project. Because genomes respond to nutritional and other environmental variables, quantitative analyses of mRNA abundance under defined nutritional and physiological states are required to understand normal metabolism and to clarify differences between normal and disease phenotypes. Reported here are comparisons of food intake, growth, serum lipids and expression of mRNA for hepatic stearoyl CoA desaturase (Scd1) and heart lipoprotein lipase (Lpl) in female BALB/cHnn mice following food deprivation and refeeding at the end of 2 wk of feeding semipurified diets with 3, 10 or 20% corn oils. Body weights and utilization of dietary energy were similar for mice fed all three diets. There were no differences in serum lipid concentrations associated with the level of dietary fat during subsequent food deprivation and refeeding, but significant differences in serum triglycerides and total serum cholesterol were observed between food-deprived and fed mice. Heart lipoprotein lipase and hepatic Scd1 mRNA expression levels were affected significantly by concentration of corn oil and by time after eating. These and other studies examining gene regulation by dietary variables and nutrient availability are discussed in relation to development of diet-regulated gene databases for laboratory animals fed semipurified diets.

Lipid desaturation regulates the balance between self-renewal and differentiation in mouse blastocyst-derived stem cells

Stem cells are defined by their ability to self-renew and differentiate, both shown in multiple studies to be regulated by metabolic processes. To decipher metabolic signatures of self-renewal in blastocyst-derived stem cells, we compared early differentiating embryonic stem cells (ESCs) and their extra-embryonic counterparts, trophoblast (T)SCs to their self-renewing counterparts. A metabolomics analysis pointed to the desaturation of fatty acyl chains as a metabolic signature of differentiating blastocyst-derived SCs via the upregulation of delta-6 desaturase (D6D; FADS2) and delta-5 desaturase (D5D; FADS1), key enzymes in the biosynthesis of polyunsaturated fatty acids (PUFAs). The inhibition of D6D or D5D by specific inhibitors or SiRNA retained stemness in ESCs and TSCs, and attenuated endoplasmic reticulum (ER) stress-related apoptosis. D6D inhibition in ESCs upregulated stearoyl-CoA desaturase-1 (Scd1), essential to maintain ER homeostasis. In TSCs, however, D6D inhibition downregulated Scd1. TSCs show higher Scd1 mRNA expression and high levels of monounsaturated fatty acyl chain products in comparison to ESCs. The addition of oleic acid, the product of Scd1 (essential for ESCs), to culture medium, was detrimental to TSCs. Interestingly, TSCs express a high molecular mass variant of Scd1 protein, hardly expressed by ESCs. Taken together, our data suggest that lipid desaturation is a metabolic regulator of the balance between differentiation and self-renewal of ESCs and TSCs. They point to lipid polydesaturation as a driver of differentiation in both cell types. Monounsaturated fatty acids (MUFAs), essential for ESCs are detrimental to TSCs.

CSIG-40. STEAROYL-COA DESATURASE 1 (SCD1) IS REQUIRED FOR WNT SIGNALING TO INDUCE AN APOPTOSIS IN IDH MUTANT GLIOMA

Abstract BACKGROUND AND HYPOTHESES SCD1, a major enzyme of saturated fatty acids, has been implicated to be important for tumor metabolic reprograming. Our previous study show that a high level of SCD1 mRNA is associated with IDH1mut lower grade gliomas. IDH1mut glioma cells are more sensitive to SFA induced apoptosis. However, the underlying mechanism remains unclear. In this study, we investigate the functions of SCD1 in IDHmut glioma and the potential contribution of SCD1 for cancer therapy of glioma. STUDY DESIGN AND METHODS The genetically engineered IDH wild-type, IDHmut and patient derived glioma cell lines were used to evaluate SCD1 functions. The expression of proteins were checked by Western-blotting assay. SCD1 was silenced by CRISPR or siRNA. The transcriptome change after SCD1 knockdown was profiled by RNA-seq or single cell RNA-seq (scRNA-seq). RESULTS AND CONCLUSIONS SCD1 transient silencing slowed down the cell growth, suggesting that SCD1 may possess an oncogenic property. RNA-seq analysis revealed that SCD1 inhibition decreased the expression of wnt-signaling pathway genes in IDH-1mut cells. scRNA confirmed that CRISPR SCD1 significantly decreased wnt signaling in the patient cell line Ts603. Therefore, we activated wnt pathway using a small chemical compound, BML-2838. Consistent with recent studies, wnt pathway induction led to a dramatically suppression of glioma cells growth. However, SCD1 silencing reversed this inhibitory effect. Further investigation revealed that SCD1 inhibition reduced the nucleus translocation of phosphorylated beta-catenin. Overall, the results suggest that SCD1 is vital for the onset of wnt pathway in glioma cells. High level of SCD1 expression may render the IDHmut glioma cells more sensitive to wnt pathway induced apoptosis. RELEVANCE AND IMPORTANCE In clinical, the 5-years survival rate of glioma remains low. SCD1 have been considered as a target for glioma therapy, recently. Our data provides a new insight on the strategy to target SCD1 in clinical.

Downregulation of hepatic lipopolysaccharide binding protein improves lipogenesis-induced liver lipid accumulation

Circulating lipopolysaccharide-binding protein (LBP) is increased in individuals with liver steatosis. We aimed to evaluate the possible impact of liver LBP downregulation using lipid nanoparticle-containing chemically modified LBP small interfering RNA (siRNA) (LNP-Lbp UNA-siRNA) on the development of fatty liver. Weekly LNP-Lbp UNA-siRNA was administered to mice fed a standard chow diet, a high-fat and high-sucrose diet, and a methionine- and choline-deficient diet (MCD). In mice fed a high-fat and high-sucrose diet, which displayed induced liver lipogenesis, LBP downregulation led to reduced liver lipid accumulation, lipogenesis (mainly stearoyl-coenzyme A desaturase 1 [Scd1]) and lipid peroxidation-associated oxidative stress markers. LNP-Lbp UNA-siRNA also resulted in significantly decreased blood glucose levels during an insulin tolerance test. In mice fed a standard chow diet or an MCD, in which liver lipogenesis was not induced or was inhibited (especially Scd1 mRNA), liver LBP downregulation did not impact on liver steatosis. The link between hepatocyte LBP and lipogenesis was further confirmed in palmitate-treated Hepa1-6 cells, in primary human hepatocytes, and in subjects with morbid obesity. Altogether, these data indicate that siRNA against liver Lbp mRNA constitutes a potential target therapy for obesity-associated fatty liver through the modulation of hepatic Scd1.

Saturated Fatty Acid-Induced Impairment of Hepatic Lipid Metabolism Is Worsened by Prohibitin 1 Deficiency in Hepatocytes.

Obesity-associated nonalcoholic fatty liver disease (NAFLD) is characterized by excessive intrahepatic lipid accumulation. Despite the increasing prevalence of NAFLD and obesity, the pathogenesis of NAFLD has not yet been clearly elucidated. Prohibitin 1 (PHB1) is mainly expressed in the inner membrane of mitochondria and is known to play an important role in hepatocyte proliferation and lipid metabolism. In this study, we investigated how PHB1 affects lipid metabolism in murine hepatocytes. To reduce the expression of PHB1, Phb1 small interfering RNA was transfected into normal murine hepatocytes (AML12), and the cells were treated with the saturated fatty acid (SFA), palmitic acid (PA), for 24 h. When PHB1 was inhibited, the cell viability decreased by ∼20%, and it was found that it diminished further after PA treatment in both control and peroxisome proliferator-activated receptor gamma (Ppar-γ) knockdown cell groups. Examination of the mRNA expression levels of key enzymes involved in lipid metabolism revealed that PHB1 led to increased stearoyl-coenzyme A desaturase-1 (Scd1) mRNA levels, which leads to an increase in the synthesis of triglycerides (TGs). It also activates the endoplasmic reticulum (ER) stress response through upregulating C/EBP homologous protein (Chop) mRNA levels. PPAR-γ, which has been reported to be upregulated in NAFLD patients, also showed elevated expression. The expression of carnitine palmitoyltransferase 1A, which is involved in the conversion of excess intracellular SFA to fatty acid by catabolism, was downregulated in the PHB1-deficient group. Furthermore, TG synthesis was further promoted by a marked increase in SCD1 mRNA levels, which was further exacerbated by elevated Chop mRNA levels and Ppar-γ disruption. Taken together, PHB1 deficiency led to altered lipid metabolism, resulting in the increased intracellular lipid accumulation and ER stress. These cytotoxic effects were shown to be further exacerbated by excessive PA treatment.

Effect of Gegen Qinlian Decoction on methylation and expression of Scd1gene in adipose tissue of insulin resistant rats and correlations between methylation and physiological and biochemical parameters

This study aimed to explore the effect of Gegen Qinlian Decoction(GQD) on the methylation and mRNA expression level of stearoyl CoA desaturase(SCD) gene in the adipose tissue of rats with insulin resistance(IR) induced by high-fat diet as well as the correlations between methylation and physiological and biochemical indicators. The animals were divided into seven groups, namely, blank control(C) group, IR model group, low-(1.65 g·kg~(-1)), medium-(4.95 g·kg~(-1)), and high(14.85 g·kg~(-1))-dose GQD(GQDL, GQDM, and GQDH) groups, rosiglitazone(RGN, 5 mg·kg~(-1)) group, and simvastatin(SVT, 10 mg·kg~(-1)) group. The rat epididymal adipose tissue was collected for detecting all the cytosine methylation levels in two fragments of Scd1 gene by bisulfite sequencing PCR(BSP). Scd1-1 was located in CG shores and Scd1-2 in CG islands, including the transcriptional start site(TSS). The Scd1 mRNA level was determined by quantitative real-time PCR(q-PCR). Spearman correlation coefficient was used to analyze the correlations between amplified fragment C methylation and physiological and biochemical indicators. The results showed that GQDM remarkably reversed the elevated CG7 methylation in the TSS upstream region of Scd1-2 triggered by high-fat diet. GQDL significantly reversed the lowered total CG methylation in the downstream region of Scd1-2 induced by the high-fat diet. GQD did not significantly improve the decreased Scd1 mRNA expression caused by high-fat diet. Changes in methylation of the total CG, CG5 and CT11 of Scd1-1 in CG shores exhibited significant negative correlations with the serum triglyceride(TG) but positive correlation with the Scd1 mRNA level. The methylation of several C sites in the TSS upstream region of Scd1-2 was positively correlated with physiological and biochemical parameters. The methylation of several CG sites in the TSS downstream region of Scd1-2 was negatively associated with physiological and biochemical parameters. Besides, the methylation of several CH sites in the downstream fragment was positively correlated with physiological and biochemical parameters. All these have demonstrated that GQD may exert the therapeutic effect by regulating the methylation of CG7 in the TSS upstream region and total CG site in the TSS downstream region of Scd1 gene. The methylation of total CG, CG5 and CT11 sites in CG shores of Scd1 gene may be important targets for regulating Scd1 mRNA level and affecting serum TG.

Combination of palmitic and stearic acids increases the expression of lipogenic genes in mammary gland explants of lactating ewes

The objective was to evaluate the effects of palmitic (PA) and stearic (SA) acids and their combination on gene expression of acetyl-CoA carboxylase alpha (ACACAα) PII, fatty acid synthase (FASN), stearoyl-CoA desaturase 1 (SCD1), fatty acid binding proteins (FABP3 and FABP4), and fatty acid CD36 (CD36) translocator in in vitro cultured lactating mammary tissue. Mammary gland explants of two Lacaune ewes rearing twins at 30 ± 5 days in milk, and with body weight of 70 ± 5 kg and body condition score of 3.0 ± 0.5 were used. Explants were cultured for 24 h in 6-well plates at 37 °C with 5% CO2 and saturated humidity. The treatments were a) Control: 3.5 mL of culture medium + 0.1 % bovine serum albumin; b) PA: 3.5 mL of culture medium +200 μM of palmitic acid; c) SA: 3.5 mL of culture medium +200 μM of stearic acid, and; d) PASA: 3.5 mL of culture medium +100 μM palmitic acid +100 μM stearic acid. There was no effect of treatment on FASN (P = 0.11). Compared to Control, PASA treatment increased ACACAα PII and CD36 mRNA abundance by 89 % (P = 0.001) and 44 % (P = 0.02), respectively, whereas, FABP4 mRNA was reduced by 44 % (P = 0.001). Compared to Control, SA increased ACACAα PII mRNA by 41 % (P = 0.001), whereas FABP4 mRNA was decreased in 41 %. Compared to PASA, the PA treatment, respectively, reduced the mRNA abundance of ACACAα PII, CD36 and FABP3 in 48, 40 and 24 % (P = 0.001) excepting that of FABP4 and SCD, which were increased by 131 and 39 % (P = 0.001), respectively. Compared to Control, all treatments decreased SCD mRNA abundance (P = 0.01). Therefore, PASA in mammary explants of lactating ewes increased the expression of genes involved in milk fat synthesis, FA uptake and cellular transport. The increased mRNA abundance of FA translocator CD36 by the combined FAs supports an important role for this gene in mammary explants.

Chemotoxicity-induced exosomal lncFERO regulates ferroptosis and stemness in gastric cancer stem cells

Cancer stem cells (CSCs) are an important cause of tumor recurrence and drug resistance. As a new type of cell death that relies on iron ions and is strictly regulated by intracellular and extracellular signals, the role of ferroptosis in tumor stem cells deserves extensive attention. Mass spectrum was applied to screen for ferroptosis-related proteins in gastric cancer (GC). Sphere-formation assay was used to estimate the stemness of gastric cancer stem cells (GCSCs). Exosomal lnc-ENDOG-1:1 (lncFERO) was isolated by ultracentrifugation. Ferroptosis was induced by erastin and was assessed by detecting lipid ROS, mitochondrial membrane potential, and cell death. Furthermore, a series of functional in vitro and in vivo experiments were conducted to evaluate the effects of lncFERO on regulating ferroptosis and chemosensitivity in GCSCs. Here, we showed that stearoyl-CoA-desaturase (SCD1) played a key role in regulating lipid metabolism and ferroptosis in GCSCs. Importantly, exosomal lncFERO (exo-lncFERO) derived from GC cells was demonstrated to promote SCD1 expression by directly interacting with SCD1 mRNA and recruiting heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1), which resulted in the dysregulation of PUFA levels and the suppression of ferroptosis in GCSCs. Moreover, we found that hnRNPA1 was also involved in lncFERO packing into exosomes in GC cells, and both in vitro and in vivo data suggested that chemotoxicity induced lncFERO secretion from GC cells by upregulating hnRNPA1 expression, leading to enhanced stemness and acquired chemo-resistance. All these data suggest that GC cells derived exo-lncFERO controls GCSC tumorigenic properties through suppressing ferroptosis, and targeting exo-lncFERO/hnRNPA1/SCD1 axis combined with chemotherapy could be a promising CSC-based strategy for the treatment of GC.

YiQi YangYin Decoction Attenuates Nonalcoholic Fatty Liver Disease in Type 2 Diabetes Rats.

Background YiQi YangYin Decoction (YQ) is a modern Chinese formula composed by the guidance of traditional Chinese medicine theory, which consists of nine traditional Chinese medicines and is applied to treat type 2 diabetes mellitus (T2DM) with nonalcoholic fatty liver in clinic in China for more than a decade. This study aims to evaluate the antidiabetes and lipid-lowering effect of YQ and explore the possible mechanisms of this action. Methods T2DM rat models were established and given YQ at three different doses for three weeks. Tissues, including pancreas islet and liver, and blood serum were collected. The levels of fasting blood glucose (FBG), fasting insulin (Fins), lipid index, such as total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL), and low-density lipoprotein (LDL), and hepatic function index such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) in serum were measured. Pancreas islet damage and liver damage were observed by hematoxylin and eosin staining. The glycogen content and lipid accumulation in liver were determined by periodic acid-Schiff (PAS) staining and Oil Red O staining. The expression levels of insulin receptor substrate 2 (IRS-2), phosphatidylinositol 3 kinase-associated p85alpha (PI3K p85α), AKT, and Glucose Transporter 2 (Glut4) in pancreas islet and AMP-activated protein kinase alpha (AMPKα), sterol regulatory element-binding protein 1c (SREBP1c), acetyl-CoA carboxylase (ACC1), and peroxisome proliferator‐activated receptor-α (PPARα) in liver were determined by western blotting. The relative expressions of ACC1, fatty acid synthase (FAS), stearoyl-CoA desaturase 1 (SCD1), carnitine palmityl transferase-1 (CPT-1), and SREBP-1 mRNA were detected by qRT-PCR. Results After administering YiQi for three weeks, the levels of fast blood glucose, fasting insulin, TC, TG, LDL, ALT, AST, and ALP were significantly decreased, while HDL significantly increased compared with the model group. YQ could obviously attenuate pancreatic damage and improve islet α- and ß-cell survival compared with the model group. Furthermore, YQ could attenuate hepatic damage caused by lipid accumulation, decrease the content of lipid, and increase the hepatic glycogen content, compared with the model group. In addition, YQ remarkably elevated the proteins expression of p-PI3K, p-AKT, and GLUT4 in pancreas islet and elevated the proteins expression of p-PI3K, p-AKT, GLUT4, p-AMPK, SREBP1, and PPARα and inhibited the expression of p-ACC1 in liver. Besides, YQ reduced the relative expression of ACC1, FAS, SERBP-1c, and SCD mRNA along with the decreased production of CPT-1 mRNA. Conclusions YQ could attenuate type 2 diabetes mellitus by improving islet α- and ß-cells via IRS-2/AKT/GLUT4 pathway and nonalcoholic fatty liver by ameliorating lipid accumulation via AMPK/PPARα/SREBP1/ACC1 pathway.

Anti-Obesity and Hypocholesterolemic Actions of Protamine-Derived Peptide RPR (Arg-Pro-Arg) and Protamine in High-Fat Diet-Induced C57BL/6J Mice.

Dietary protamine can ameliorate hyperlipidemia; however, the protamine-derived active peptide and its hypolipidemic mechanism of action are unclear. Here, we report the discovery of a novel anti-obesity and hypocholesterolemic peptide, RPR (Arg-Pro-Arg), derived from protamine in mice fed a high-fat diet for 50 days. Serum cholesterol levels were significantly lower in the protamine and RPR groups than in the control group. White adipose tissue weight was significantly decreased in the protamine and RPR groups. The fecal excretion of cholesterol and bile acid was significantly higher in the protamine and RPR groups than in the control group. We also observed a significant decrease in the expression of hepatic SCD1, SREBP1, and adipocyte FAS mRNA, and significantly increased expression of hepatic PPARα and adipocyte PPARγ1 mRNA in the protamine group. These findings demonstrate that the anti-obesity effects of protamine are linked to the upregulation of adipocyte PPARγ1 and hepatic PPARα and the downregulation of hepatic SCD1 via SREBP1 and adipocyte FAS. RPR derived from protamine has a crucial role in the anti-obesity action of protamine by evaluating the effective dose of adipose tissue weight loss.

Modulation of Cholesterol Metabolism Improves Response to Enzalutamide Treatment in Prostate Cancer

Abstract Objectives Prostate cancer (PCa) growth is mediated by androgens via activation of androgen receptor (AR). Accordingly, androgen deprivation therapy (ADT) is the gold standard for the treatment of advanced PCa, but progression to castration-resistant PCa (CRPC) follows. Enzalutamide (ENZ) is an AR antagonist used for the management of CRPC. However, patients acquire resistance to the drug in a short period. As cholesterol metabolism is dysregulated in PCa and lipogenesis is upregulated by AR signaling, we hypothesized that inhibition of cholesteryl ester formation and suppression of lipogenesis by blockage of sterol-O-acyltransferase 1 (SOAT1) could enhance the response to ENZ. Methods The mRNA expression of SOAT1 in PCa patients was analyzed using Oncomine and TCGA database. Survival analysis of TCGA PCa patients data was executed using cBioPortal. 22RV1 cells inherently resistant to ENZ, were challenged to avasimibe (AVA), a pharmacological inhibitor of SOAT1, with or without ENZ. Results We found SOAT1 mRNA is significantly overexpressed in prostate carcinoma compared to the normal tissue in separate datasets (Taylor 3; Grasso; Liu). Analysis of the TCGA PCa dataset among patients who had undergone ADT showed longer disease-free status (P = 0.039) and a trend toward better overall survival status (P = 0.066) in low SOAT1 mRNA expressing patients. Moreover, SOAT1 mRNA expression positively correlated with AR mRNA expression with Pearson coefficient of 0.5 (P = 7.475e-6). We also found that combination of 20 μM ENZ and 2 μM AVA reduced 52% of cell counts after 5 days and 53% of colony formation after 2 weeks, whereas AVA resulted in 20% and 28% reduction, respectively, with no effect from ENZ. Synergism of these two drugs was observed based on MTT assay with Chou-Talalay's combination index method. 4 μM AVA treatment for 24h downregulated AR downstream nkx3.1 mRNA level with no difference in AR or ARV7 mRNA levels. AVA treatment also downregulated lipogenic SCD1 mRNA level, inhibition of which was previously reported to enhance response to ENZ. Conclusions SOAT1 is a potential biomarker predictive of the success of ENZ treatment in PCa according to TCGA data. Our in vitro study further supports that SOAT1-regulated cholesterol metabolism is an important factor for the ENZ response. Funding Sources Purdue Research Foundation, Ralph W. and Grace M. Showalter Research Trust.

Impact of High-Sucrose Diet on the mRNA Levels for Elongases and Desaturases and Estimated Protein Activity in Rat Adipose Tissue.

Fatty acids (FAs) present in the adipose tissue (AT) can be modified by elongases and desaturases. These enzymes are regulated by different factors including nutrients. The aim of the study was to evaluate the impact of high-sucrose diet (HSD; 68% sucrose) on the levels of mRNAs for elongases (Elovl2, Elovl5, Elovl6) and desaturases (Fads1, Fads2, Scd) and on the activity of the corresponding proteins in the rat AT. Male Wistar rats were randomized into two study groups: fed with an HSD and with a standard diet (ST). The mRNA levels were determined by a semi-quantitative reverse transcription-PCR. FA composition was analyzed by gas chromatography, and FA ratios were used to estimate the activity of the enzymes. In the HSD rats, the levels of Elovl5, Elovl6, Fads1, and Scd mRNAs were higher, while the level of Fads2 mRNA was lower than in the ST group. Higher levels of Elovl5 and Elovl6 mRNAs corresponded to higher relative activities of these enzymes, while downregulation of the Fads2 mRNA was associated with the lower activity of this desaturase. In contrast, an increase in the level of Scd mRNA was accompanied by a decrease in the enzyme activity. Less monounsaturated FAs were detected in the AT of HSD rats than in the ST group. The composition of individual FAs differed between the groups. This study supports the notion that the regulation of mRNA levels and activity of both elongases and desaturases play an important role in managing the AT lipid composition in response to changes in the dietary status.

RAGE Mediates Cholesterol Efflux Impairment in Macrophages Caused by Human Advanced Glycated Albumin.

We addressed the involvement of the receptor for advanced glycation end products (RAGE) in the impairment of the cellular cholesterol efflux elicited by glycated albumin. Albumin was isolated from type 1 (DM1) and type 2 (DM2) diabetes mellitus (HbA1c > 9%) and non-DM subjects (C). Moreover, albumin was glycated in vitro (AGE-albumin). Macrophages from Ager null and wild-type (WT) mice, or THP-1 transfected with siRNA-AGER, were treated with C, DM1, DM2, non-glycated or AGE-albumin. The cholesterol efflux was reduced in WT cells exposed to DM1 or DM2 albumin as compared to C, and the intracellular lipid content was increased. These events were not observed in Ager null cells, in which the cholesterol efflux and lipid staining were, respectively, higher and lower when compared to WT cells. In WT, Ager, Nox4 and Nfkb1, mRNA increased and Scd1 and Abcg1 diminished after treatment with DM1 and DM2 albumin. In Ager null cells treated with DM-albumin, Nox4, Scd1 and Nfkb1 were reduced and Jak2 and Abcg1 increased. In AGER-silenced THP-1, NOX4 and SCD1 mRNA were reduced and JAK2 and ABCG1 were increased even after treatment with AGE or DM-albumin. RAGE mediates the deleterious effects of AGE-albumin in macrophage cholesterol efflux.