SCD1 Expression Research Articles

Identification of differentially expressed genes and polymorphisms related to intramuscular oleic-to-stearic fatty acid ratio in pigs.

The intramuscular oleic-to-stearic fatty acid ratio (C18:1n-9/C18:0) is an important indicator of the biosynthesis and desaturation of fatty acids in muscle. By using an RNA-Seq approach in muscle samples from 32 BC1_DU (25% Iberian and 75% Duroc) pigs with divergent values (high: H and low: L) of C18:1n-9/C18:0 fatty acids ratio, a total of 81 differentially expressed genes (DEGs) were identified. Functional analyses of DEGs indicate that mainly peroxisome proliferator-activated receptor signaling pathway (associated genes: PPARG, SCD, PLIN1, and FABP3) was overrepresented. Notably, SCD is directly involved in the conversion of C18:0 to C18:1n-9, and PPARG is a transcription factor regulating lipid metabolism genes, including SCD. However, other DEGs (e.g., ACADVL, FADS3, EPHB2, HGFAC, NGFR, NR0B2, MDH1, MMAA, PPP1R1B, SFRP5, RAB30, and TRARG1) are plausible candidate genes to explain the phenotypic differences of the C18:1n-9/C18:0 ratio. Interestingly, seven genetic variants within the SCD (including the well-known AY487830:g.2228T>C SNP and other novel genotyped polymorphisms) are associated with two haplotypes. Although the haplotypes are segregating at different frequencies in the H and L groups, they do not fully explain the desaturation ratios or the SCD expression levels. A more complex model, including polyunsaturated fatty acids such as C18:2n-6, C20:4n-6, and C18:3n-3, is suggested to explain the regulation of the C18:1n-9/C18:0 desaturation ratio in porcine muscle.

The Interaction of Microalgae Dietary Inclusion and Forage-to-Concentrate Ratio on the Lipid Metabolism-Related Gene Expression in Subcutaneous Adipose Tissue of Dairy Goats.

Long-chain polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (DHA) have been shown to be effective in enhancing the quality of ruminant products, including meat and milk. However, under these dietary conditions, the de novo lipogenesis could be influenced, too. On the other hand, even if the forage-to-concentrate ratio (F:C) is also a key factor affecting lipid metabolism in small ruminants, there is scarce information about its interaction with dietary PUFA. This study investigates the potential of the F:C ratio as a lever to manipulate lipid metabolism in dairy goats under high dietary PUFA supplementation. For this purpose, twenty-two crossbred dairy goats [Alpine × Local (Greek) breeds] (BW = 50.6 ± 6.1 kg) at early lactation (70 ± 10 days in milk) during the age of 3-4 years old, were separated into two homogeneous subgroups (n = 11). In the first phase, each goat was fed 20 g Schizochytrium spp./day followed by either a high-forage (20 HF) or a high-grain (20 HG) diet, while in the second phase, each goat was fed 40 g Schizochytrium spp./day followed once again either a high-forage (40 HF) or a high-grain (40 HG) diet. The F:C ratio of a high-forage and high-grain diet was 60:40 and 40:60, respectively. Tail fat tissue samples were collected by biopsy on the 42nd day of each experimental phase (last day). Significant decreases (p < 0.05) in the gene expression of ACACA, CBR2, COX4I1, ELOVL5, ELOVL7, LEP, and SCD were presented in goats fed 40 g compared to those fed 20 g Schizochytrium spp., while the gene expression of ACACA, AGPAT2, AGPAT3, ELOVL5, ELOVL6, EPHX2, FASN, and SCD was decreased in high grain compared to high-forage diets. This study also indicated that with the aim to enrich goat products with PUFA by increasing their levels in the diet, lipid metabolism is negatively affected. However, a diet with higher forage inclusion can partially attenuate this condition.

STEM-08. LIPID SATURATION HOMEOSTASIS PRESENTS A TARGETABLE VULNERABILITY IN MYC-AMPLIFIED GROUP 3 MEDULLOBLASTOMA

Abstract Medulloblastoma (MB) is the most common malignant pediatric brain cancer, originating from the cerebellum. Despite advancements in standard of care (SoC), MB remains fatal for 30% of patients. Tumor relapse, spinal metastasis and treatment resistance are the most prevalent in MYC-driven Group 3 MB (G3-MB). Patients surviving SoC are faced with life-long neurocognitive and neurodevelopmental deficits. These issues highlight the urgent need for improved treatment modalities. Reprogramming of cellular lipid metabolism is an emerging hallmark of cancer and may yield novel cancer-specific therapeutic options. Here we explore the lipidome of both G3-MB and its proposed cell of origin, human neural stem cells (hNSCs) by comparing untargeted lipidomics using Liquid-Chromatography-Mass Spectrometry (LC-MS). Comparative analyses revealed a differential abundance of distinct lipid species in G3-MB, with an overall reduced saturation level of fatty acids (FAs). These findings implicate the de novo lipid synthesis (DNL) pathway. We identified the enzymes involved in DNL to be essential for MB survival in our genome-wide CRISPR KO screen. Additionally, mRNA expression of the DNL enzymes increases at relapse in our SoC-adapted murine patient-derived xenograft (PDX) model. Pharmacological and genetic targeting of the DNL enzyme Stearoyl-CoA Desaturase 1 (SCD1) selectively targets G3-MB. Furthermore, small molecule treatment of SCD1 demonstrates efficacy against G3-MB PDX models in vivo. We identified SCD expression as a prognostic marker in Group 3 and 4 MB patients and identified possible pathways for MB treatment. Overall, these findings indicate that SCD1 is a potent target for the treatment of G3-MB.

Integrated network pharmacology, metabolomics and molecular docking analysis to reveal the mechanisms of quercetin in the treatment of hyperlipidemia

Hyperlipidemia (HLP) is a significant contributor to cardiovascular diseases. Quercetin (QUE), a naturally occurring flavonoid with diverse bioactivities, has garnered attention due to its potential therapeutic effects. However, the precise mechanisms underlying the effects of QUE on HLP remain unclear. In this study, an ultra-high-performance liquid chromatography-quadrupole/electrostatic field Orbitrap high-resolution mass spectrometry (UPLC-Q-Exactive-MS) metabolomics strategy was employed to obtain metabolite profiles, and potential biomarkers were identified following data analysis. Network pharmacology and Drug Affinity Responsive Target Stability (DARTS) assays were utilized to explore the potential targets of QUE for HLP treatment. The results of metabolomics and network pharmacology were then integrated to identify the key targets and metabolic pathways involved in the therapeutic action of the QUE against HLP. Molecular docking and experimental validation were performed to confirm these key targets. A comprehensive database search identified 138 QUE-HLP-related targets. A protein-protein interaction (PPI) network was constructed using STRING, and the shared targets were filtered with Cytoscape. Among these, AKT1, TNF, VEGFA, mTOR, SREBP1, and SCD emerged as potential therapeutic targets. These findings were validated using in vitro cell experiments. Additionally, the mechanism of action of QUE against HLP was evaluated by integrating network pharmacology with metabolomics, identifying two metabolomic pathways crucial to HLP treatment. DARTS experiments confirmed the stable binding of QUE to FASN, p-mTOR, SREBP1, and p-AKT. In HepG2 cells treated with palmitic acid (PA), QUE significantly reduced the mRNA expression of ACLY, ACACA, FASN, and SCD (p < 0.05). Western blot analysis revealed that PA significantly increased protein expression of p-mTOR, SREBP1, FASN, and p-AKT (p < 0.05). In summary, our study provides novel insights into the protective mechanisms of QUE against HLP and offers valuable information regarding its potential benefits in clinical treatment.

Performance, Meat Quality and Gene Expression of Grazing Lambs Supplemented with Macadamia Oil and Vitamin E

Macadamia oil has high concentrations of oleic and palmitoleic fatty acids, which can increase tissue sensitivity to insulin, improving glucose absorption efficiency, and reducing lipogenesis through gene modulation. The objective of this study was to evaluate the effects of macadamia oil associated with vitamin E supplementation on performance, blood parameters, meat quality and sensory characteristics, meat fatty acid profile, and expression of genes associated with lipid metabolism in grazing lambs. The experimental treatments were control diet (Control), Control + 0.1% of body weight of macadamia oil (MO), MO + 745 IU of vitamin E/dry matter (MOVE). Macadamia oil improved feed efficiency, reflecting a lower dry matter intake, as the average daily weight gain did not differ from Control. Meat quality parameters were not affected by macadamia oil or vitamin E supplementation. Supplementation with macadamia oil improved meat appearance, flavor, and overall liking. Supplementation with macadamia oil provided a higher proportion of C18:3 n3 and a lower proportion of CLA. The expression of SREBP-1c, PPAR-α, SCD1, and ELOVL6 genes were not modified with the supplementation of macadamia oil and vitamin E. In conclusion, supplementation with macadamia oil improves feed efficiency and meat quality; and the inclusion of 745 IU of vitamin E/kg of dry matter for grazing lambs reduces 36% of lipid oxidation of the meat.

GPR37 promotes colorectal cancer against ferroptosis by reprogramming lipid metabolism via p38-SCD1 axis.

Colorectal cancer (CRC) is a prevalent malignant tumor worldwide, leading to significant morbidity and disease burden. Diagnostic indicators and treatment objectives for CRC are urgently needed. This study demonstrates that GPR37, a GPCR receptor, is highly expressed in CRC. Depletion of GPR37 significantly reduced CRC tumor cell growth both in vitro and in vivo. Further tests showed that GPR37 protects cancer cells from ferroptosis by upregulating SCD1 expression, thereby modulating lipid metabolism, suppressing the level of reactive oxygen species, and mitigating ferroptosis. Mechanistic studies have shown that GPR37 modulates lipid metabolism in tumor cells by promoting SCD1 transcription via the MAPK-p38 signaling pathway. Our results reveal the pro-carcinogenic effect of GPR37 in primary CRC and suggest that targeting GPR37 could be a potential therapeutic target for CRC.

PSVII-19 Effects of silage particle size on beef quality and muscle lipogenesis of finishing Nellore heifers

Abstract The objective of this study was to evaluate the effect of corn silage particle size on beef quality and expression of gluconeogenic and lipogenic genes in feedlot-finished Nellore heifers. Nellore heifers (n = 94), with an initial body weight (BW) of 249.71 ± 34.62, were allotted into 32 pens (three animals per pen) in a completely randomized design, with 2 treatments and 16 repetitions. The treatments were corn silage with a particle size of 13 mm (short) or 24 mm (long). The feeding period lasted 101 d, with the first 15 d for diet adaptation. After slaughter, samples of the longissimus thoracis muscle (LT) from the left side of the half carcass and liver were taken for beef quality and gene expression analyses. The chemical composition of the beef was analyzed using near infrared according to the AOAC method 2007-04, using the FoodScanTM equipment (AOAC method: 2007-04; FOSS, Hillerod, Denmark). RT-qPCR analyses of each gene investigated were carried out using cDNA from 16 biological replicates per treatment (1 heifer chosen randomly in each pen), with each biological replicate subjected to 2 technical replicates. Relative gene expression analyses were calculated using the delta delta ct method and the reference genes used were ACTB and GAPDH. The normality of all experimental data was checked using the Shapiro-Wilk test in SAS software. When the data did not present a normal distribution, transformation was performed using PROC RANK. The model included particle size as a fixed effect and pen as a random effect. There was no treatment effect on collagen, moisture, and mineral content (P &amp;gt; 0.10), but muscles from heifers fed short particle sizes tended to have greater protein content (23.3 versus 22.9; P = 0.098), while muscles from heifers fed with long particles had greater intramuscular fat content (2.62 versus 3.28; P = 0.05). For liver gene expression, heifers fed short particle sizes tended to have greater expression of the PC gene (1.00 versus 0.82; P = 0.06), while PEPCK2 had higher expression in heifers fed long particles (1.00 versus 1.18; P = 0.04). In addition, the long particle size of corn silage affected the expression of PPARA (P = 0.001), and there was no effect of diets (P &amp;gt; 0.05) on PPARG and SREBF1 expressions (Table 1). Expression of LPL, FABP4, SCD1, CPT2 (P &amp;lt; 0.001), and ACACA (P = 0.017) genes increased in the muscle of heifers fed long particle size. Therefore, it is concluded that the use of corn silage with long particle size in feedlot diets has the potential to increase the expression of genes involved in lipogenesis and then increase intramuscular fat in Nellore heifers.

Proteogenomic Identification and Analysis of KIF5B as a Prognostic Signature for Hepatocellular Carcinoma.

Metabolic disorders are significant risk factors for liver cancer, particularly Hepatocellular Carcinoma (HCC). However, the molecular genetic basis of metabolic reprogramming in the liver remains largely uncertain. This study aimed to investigate some novel prognostic biomarkers in HCC by using proteogenomic and transcriptomic analysis and explore the potential role of specific prognostic genes in HCC. Here, we have presented a proteogenomic analysis of 10 pairs of HCC. Protein co-expression and pathway analysis were performed to investigate the biological characteristics of HCC. Protein and mRNA expression profiles of multi-cohorts were integrated to detect novel prognostic protein markers of HCC. The carcinogenic roles of candidate prognostic markers were further evaluated by MTS assay, colony formation, monolayer wound healing assay, and xenograft models. A total of 2086 proteins with significantly different expressions were detected in HCC. Pathways related to oncogenic signaling and insulin-related metabolism have been found to be dysregulated and differentially regulated in HCC. We have identified the novel prognostic biomarkers, KIF5B, involved in liver metabolic reprogramming. The biomarkers were identified using multivariable COX regression analysis from two independent proteomic datasets (Fudan Cohort and our recruited cohort) and the TCGA mRNA database. Both the protein and mRNA up-regulation of KIF5B have been found to be associated with a poor clinical outcome in HCC. Insulin activated the protein expression of KIF5B in HCC. Knocking out KIF5B expression by sgRNA decreased the protein expression of FASN and SCD1 and the intracellular triglyceride concentration. Silencing KIF5B suppressed HCC cell proliferation and colony formation in vitro, as well as HCC growth in xenograft models. Our findings have suggested KIF5B protein to function as a novel prognostic biomarker in HCC. KIF5B expression has been found to activate the AKT/mTOR pathway and reprogram triglyceride metabolism, leading to HCC development. Targeting KIF5B may be an effective strategy in the clinical treatment of HCC.

Down-regulation of miR-29 improves lipid metabolism in fatty liver of dairy cows

In this study, we conducted a thorough investigation into the mechanisms by which miR-29 influences lipid metabolism. Thirty-two cows were selected and categorized into distinct groups based on their liver triglyceride (TG) content: healthy, mild fatty liver, and moderate fatty liver groups. Dairy cows with moderate fatty liver showed higher levels of hepatic lipid accumulation, MDA content and serum AST, ALT and ALP contents and lower hepatic catalase CAT and SOD activities. Subsequently, hepatocytes isolated from healthy calves were exposed to sodium oleate (SO) in the presence or absence of pre-incubation with miR-29 inhibitor or inhibitor NC. Pre-transfection with miR-29 inhibitor resulted in reduced hepatocyte lipid accumulation and MDA levels, as well as decreased levels of AST, ALT, and ALP in the supernatant. In the miR-29 inhibitor + SO group, there was an increase in the expression of SREBP-1, FAS, SCD1, and Sirt1. Meanwhile, the expression of PPARα, CPT1, CPT2, PGC-1α, NRF-1, UCP2, and miR-29 were observed to be decreased. In comparison to the miR-29 inhibitor + SO group, some of the measured indicators showed partial reversal in the miR-29 inhibitor + siSirt1 + SO group. Collectively, these findings provide evidence that miR-29 may play a crucial role in the pathogenesis of fatty liver in dairy cows.

The role of ESM1 in the lipids metabolic reprogramming and angiogenesis of lung adenocarcinoma cells

BackgroundLung adenocarcinoma (LUAD) is one of the respiratory diseases with high mortality and incidence. As an important angiogenic factor, (Endothelial cell-specific molecule 1) ESM1 plays an important role in the occurrence and development of LUAD. However, the role and molecular mechanism of ESM1 on LUAD metabolic reprogramming and angiogenesis remain unclear. MethodsWe used multiple databases to analyze the prognostic significance and potential function of ESM1 in patients with LUAD. The expression of ESM1 in LUAD cells was down-regulated/overexpressed by RNA interference, and the effects of ESM1 on the proliferation, migration, lipid metabolism and angiogenesis of LUAD cells in vitro and in vivo were analyzed using MTT, EdU, wound healing, oil red O, tubule formation, xenograft tumor model and chicken embryo allantoic model. ResultsESM1 is closely associated with poor prognosis in LUAD patients. ESM1 promotes LUAD proliferation, migration, fatty acid synthesis and angiogenesis. It also accelerates the proliferation, migration, lipid synthesis and tubule formation of endothelial cells in the tumor microenvironment in the form of secreted protein. Mechanically, ESM1 can promote the activation of AKT signaling pathway and up-regulate the expression of SCD1 and FASN. ConclusionOur results suggest that ESM1 promotes the proliferation, migration, lipid reprogramming, and angiogenesis of LUAD cells by activating the AKT signaling pathway, suggesting that ESM1 may be a potential therapeutic target and prognostic marker in LUAD patients.

Spliceosomal GTPase Eftud2 deficiency-triggered ferroptosis leads to Purkinje cell degeneration

Spliceosomal GTPase elongation factor Tu GTP binding domain containing 2 (EFTUD2) is a causative gene for mandibulofacial dysostosis with microcephaly (MFDM) syndrome comprising cerebellar hypoplasia and motor dysfunction. How EFTUD2 deficiency contributes to these symptoms remains elusive. Here, we demonstrate that specific ablation of Eftud2 in cerebellar Purkinje cells (PCs) in mice results in severe ferroptosis, PC degeneration, dyskinesia, and cerebellar atrophy, which recapitulates phenotypes observed in patients with MFDM. Mechanistically, Eftud2 promotes Scd1 and Gch1 expression, upregulates monounsaturated fatty acid phospholipids, and enhances antioxidant activity, thereby suppressing PC ferroptosis. Importantly, we identified transcription factor Atf4 as a downstream target to regulate anti-ferroptosis effects in PCs in a p53-independent manner. Inhibiting ferroptosis efficiently rescued cerebellar deficits in Eftud2 cKO mice. Our data reveal an important role of Eftud2 in maintaining PC survival, showing that pharmacologically or genetically inhibiting ferroptosis may be a promising therapeutic strategy for EFTUD2 deficiency-induced disorders.

Exosomes derived from periodontitis induce hepatic steatosis through the SCD-1/AMPK signaling pathway

AimTo investigate the impact of exosomes released by Porphyromonas gingivalis-Lipopolysaccharide activated THP-1 macrophages and human periodontal ligament fibroblasts on hepatocyte fat metabolism. ResultsThe liver of rats with experimental periodontitis showed obvious steatosis and inflammation compared with control rats. The culture supernatant of macrophages and human periodontal ligament fibroblasts (hPDLFs), when stimulated with Pg-LPS, induced lipogenesis in HepG2 cells. Furthermore, the lipid-promoting effect was effectively inhibited by the addition of the exosome inhibitor GW4869. Subsequently, we isolated exosomes from cells associated with periodontitis. Exosomes released by Pg-LPS-stimulated macrophages and hPDLFs are taken up by hepatocytes, causing mRNA expression related to fat synthesis, promoting triglyceride synthesis, and aggravating NAFLD progression. Finally, two sets of exosomes were injected into mice through the tail vein. In vivo experiments have also demonstrated that periodontitis-associated exosomes promote the development of hepatic injury and steatosis, upregulate SCD-1 expression and inhibit the AMPK signaling pathway. ConclusionsIn conclusion, we found that exosomes associated with periodontitis promote hepatocyte adipogenesis by increasing the expression of SCD-1 and suppressing the AMPK pathway, which indicates that close monitoring of the progression of stomatopathy associated extra-oral disorders is important and establishes a theoretical foundation for the prevention and management of fatty liver disease linked to periodontitis.

Impact of Feeding Systems on Performance, Blood Parameters, Carcass Traits, Meat Quality, and Gene Expressions of Lambs

The aim of this study was to investigate the effects of feeding systems on the growth performance of Santa Inês x Dorper lambs, meat quality, fatty acid profile, and gene expression. Thirty lambs at an initial body weight of 22.6 ± 2.59 kg were randomly assigned to one of three feed systems: a grazing system with 1.2% body weight concentrate supplementation (GS); a feedlot system with 28% forage and 72% concentrate (FFC); or feedlot with 85% whole corn grain and 15% pellets (FHG). The lambs were slaughtered after 60 days of experiment. Average daily gain, glucose, and insulin concentration were higher for lambs on FHC than lambs on a GS feeding system. The fatty acid profile in the meat of the lambs fed GS showed a higher proportion of c9t11-C18:2, C20:5, C22:5, and C22:6 compared with FFC and FHC (p &lt; 0.05). Meat tenderness was lower for lambs under FFC treatment compared with GS and FHG. FHG treatment provides better performance and higher deposition of lipid content in meat compared with GS and FHG. The expression of the genes SCD-1, SREBP1-c, and EVOL6 was greater in lambs undergoing GS and FHC treatments compared with FFC. Results of this research showed a reduced performance of grazing lambs compared with the feedlot system; however, it enhanced the fatty acid profile with increased levels of polyunsaturated acids and reduced n6/n3 ratio.

Lactate drives the ESM1–SCD1 axis to inhibit the antitumor CD8+ T-cell response by activating the Wnt/β-catenin pathway in ovarian cancer cells and inducing cisplatin resistance

Ovarian cancer (OC) is a gynecological malignancy that results in a global threat to women’s lives. Lactic acid, a key metabolite produced from the glycolytic metabolism of glucose molecules, is correlated with tumor immune infiltration and platinum resistance. In our previous study, we found that endothelial cell-specific molecule 1 (ESM1) plays a key role in OC progression. This study revealed that lactate could upregulate ESM1, which enhances SCD1 to attenuate the antitumor CD8+ T-cell response. ESM1 and SCD1 expression levels were significantly greater in OC patients with high lactic acid levels than in those with low lactic acid levels. Further mechanistic studies suggested that the Wnt/β-catenin pathway was inactivated after ESM1 knockdown and rescued by SCD1 overexpression. IC50 analysis indicated that the ESM1–SCD1 axis induces the resistance of OC cells to platinum agents, including cisplatin, carboplatin, and oxaliplatin, by upregulating P-gp. In conclusion, our study indicated that the induction of SCD1 by lactic acid-induced ESM1 can impede the CD8+ T-cell response against tumors and promote resistance to cisplatin by activating the Wnt/β–catenin pathway in ovarian cancer. Consequently, targeting ESM1 may have considerable therapeutic potential for modulating the tumor immune microenvironment and enhancing drug sensitivity in OC patients.

Anethum graveolens L. restores expression of free fatty acid synthesis-related genes in high fat induced-HepG2 cells

IntroductionThe ethanolic extract of Anethum graveolens (dill) and its major constituents, chlorogenic acid (CGA) and ellagic acid (EA), were investigated for hepatoprotective effects in a HepG2 cell fatty liver model. MethodsHepG2 cells were induced with a combination of oleic (1mM OA) and palmitic (1mM PA) acids and treated with either 10 µM fenofibrate, 1-10 µg/mL CGA or EA, 60-360 µg/mL A. graveolens extract, or left untreated (n=4-5 per group). After 48 hours, cell medium and cells were collected for alanine transaminase (ALT), aspartate transaminase (AST), reactive oxygen species (ROS), and fatty acid accumulation assays. The mRNA and protein expression levels of free fatty acid (FFA) synthetic pathway-related genes were determined using reverse transcription/real-time polymerase chain reaction and Western blotting analysis, respectively. ResultsHepG2 cells treated with OA and PA showed increased ALT, AST, and ROS levels, fatty acid accumulation, and modified mRNA and protein expression of PPAR, SREBP1, ACC, ACOX, FAS, SCD1, and HMGCR fatty acid synthesis-related genes. The CGA, EA, and A. graveolens extract showed hepatoprotective activities in OA and PA-induced HepG2 cells by preventing fatty acid accumulation and restoring mRNA and protein expression levels of the fatty acid synthesis-related genes to control levels, with comparable efficacy to the standard anti-lipidemic drug, fenofibrate. Furthermore, CGA, EA, and A. graveolens extract did not increase ALT and ROS levels in HepG2 cells, in contrast to fenofibrate. ConclusionA. graveolens extract, CGA, and EA are good candidates for development as preventive health supplements for fatty liver disease therapy.

Identification of proteins related to SIS3 by iTRAQ and PRM-based comparative proteomic analysis in cisplatin-induced acute kidney injury.

Cisplatin is a commonly used nephrotoxic drug and can cause acute kidney injury (AKI). In the present study, isobaric tags for relative and absolute quantification (iTRAQ) and parallel reaction monitoring (PRM)-based comparative proteomics were used to analyze differentially expressed proteins (DEPs) to determine the key molecular mechanism in mice with cisplatin-induced AKI in the presence or absence of SIS3, a specific p-smad3 inhibitor, intervention. The cisplatin-induced AKI mouse model was established and treated with SIS3. We used iTRAQ to search for DEPs, PRM to verify key DEPs and combined Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) for bioinformatics analysis. We then assessed lipid deposition, malondialdehyde (MDA) and reactive oxygen species (ROS) and detected the expression of SREBF1, SCD1, CPT1A, PPARα and NDRG1 in vitro. Proteomic analysis showed that the identified DEPs were mainly enriched in energy metabolism pathways, especially in lipid metabolism. When SIS3 was applied to inhibit the phosphorylation of Smad3, the expression of NDRG1 and fatty acid oxidation key proteins CPT1A and PPARα increased, the expression of lipid synthesis related proteins SREBF1 and SCD1 decreased and the production of lipid droplets, MDA and ROS decreased. SIS3 alleviates oxidative stress, reduces lipid accumulation and promotes fatty acid oxidation through NDRG1 in cisplatin-induced AKI. Our study provides a new candidate protein for elucidating the molecular mechanisms of fatty acid metabolism disorders in cisplatin-induced acute kidney injury.

Overcoming chemoresistance in triple-negative breast cancer (TNBC): Targeting PD-L1 stability and ferroptosis through integrated lipid metabolism and immune modulation.

e15149 Background: Triple-negative breast cancer (TNBC) is notorious for its aggressive nature and high recurrence rates, exacerbated by the lack of specific molecular targets, leading to poor prognosis and emergent chemoresistance. Our study explores ferroptosis mechanisms in TNBC, focusing on the interaction between lipid metabolism and immune system modulation to identify targets that enhance chemosensitivity, potentially improving chemotherapy efficacy. Methods: We employed RNA transcriptomics, proteomics, metabolomics, and lipidomics to compare gene transcription, protein expression, and metabolic profiles between TNBC cell lines MDA-MB-231/ADR (doxorubicin-resistant) and MDA-MB-231/S (sensitive). The impact of the ferroptosis inducer Erastin on MDA-MB-231/ADR was assessed through lipidomics. We also performed gene expression profiling on 152 TNBC patients unresponsive to Anthracycline-based chemotherapy, correlating with data from TCGA and METABRIC. Functional loss and gain experiments were undertaken to explicate the role of the SCD1-TRIM28-PD-L1 axis in mediating ADR resistance. Immunohistochemistry and RT-qPCR analyses were performed on tumor tissues and serum EVs from TNBC patients to identify chemosensitivity-enhancing targets. Results: Our investigation revealed marked transcriptional and proteomic variances between MDA-MB-231/ADR and MDA-MB-231/S cell lines, with SCD1 showing significant upregulation at both mRNA and protein levels. Metabolomic analyses revealed distinct lipid metabolic profiles between these two cell lines. Further studies found that Erastin treatment increased PD-L1 expression, along with changes in SCD1, p53, and TNFAIP3 expression levels. These molecules are closely associated with poor prognosis and resistance to therapy. Our findings also elucidated that TRIM28 modulates PD-L1 stability via SUMOylation and facilitates p53 ubiquitination and degradation through a TRIM28-MDM2 dependent pathway, thereby impacting immune surveillance and therapeutic response. Additionally, in TNBC patients treated with anthracycline-based chemotherapy, higher SCD1 and TNFAIP3 but lower TRIM28 expressions were observed in the PD/SD group compared to PR/CR. Similar expression patterns were observed in serum EVs. Conclusions: Our study highlights the potential of targeting the SCD1-TRIM28-PD-L1 axis in TNBC to overcome chemoresistance. We propose combining SCD1 inhibition with ferroptosis inducers to enhance PD-L1 blockade efficacy, offering a promising approach for TNBC patients with limited response to Anthracycline-based chemotherapy. This investigation represents a pivotal step towards advancing targeted therapeutics in TNBC, potentially transforming the clinical management of this aggressive and refractory breast cancer subtype.

Myostatin deletion alters hormone metabolism shifts in obese skeletal muscle of C57/Bl6 mice

Objective: Myostatin deletion improves cardiometabolic disease outcomes observed in obesity without any changes in activity in mice. Hormone balance is dysregulated in obesity, resulting in low testosterone and high estradiol levels, which have been shown to correlate with higher risk for developing associated cardiometabolic disease outcomes. However, the basis of these alterations and how they impact factors that improve obese cardiometabolic outcomes are unknown. Methods: Control and obese mice ( db/db) with or without myostatin deletion to induce hypermuscularity were used. Plasme from mice were analyzed for hormone levels via radioimmunoassay (RIA). Aromatase inhibition was performed via dosing 10mg/kg/day via water. Quantitative PCR was used cytochrome P450 enzymes involved in estrogen metabolism in the liver, skeletal muscle, and visceral white adipose tissue. C2C12 overexpression of CYP1B1 and treatment with hydroxyestrogens in vitro was performed and respective enzyme mRNA expression assessed. Results: Deletion of myostatin increased muscle mass by &gt;30% and resulted in and improved glucose tolerance in the context of obesity without any changes in activity. Obesity decreased plasma testosterone 30% and increased estrogen 20% with no change in gonadal weight, which was improved in the absence of myostatin. CYP1B1, an enzyme that converts estradiol to toxic hydroxy estrogens, showed 2.5-fold expression in obese skeletal muscle, which is reduced in the absence of myostatin, with no change in other cytochrome P450s involved in estrogen metabolism. Inhibition of aromatase reduces estrogen and improves testosterone plasma concentration, indicating the excess estrogen in obesity is derived primarily from testosterone conversion. Aromatase expression was increased in obesity but unaffected by changes in muscle mass, this indicates an alteration to downstream estrogen metabolism. In C2C12 cells, overexpression of myostatin recapitulated changes in CYP1B1 expression seen in vivo, suggesting a direct link between the myokine and sex hormone metabolism. In addition, treatment of C2C12 cells with CYP1B1 derived hydroxyestrogens caused a tandem increase in SCD1 expression, indicating a causal link between CYP1B1 activity in obesity to increased triglyceride synthesis. Conclusion: In summary, obesity causes a shift in sex hormone levels towards estrogen production, which is improved by myostatin deletion. A potential mechanism responsible could be altered estrogen metabolism, leading to decreased estrogen levels without restoration of androgen levels. These data suggest CYP1B1 drives the conversion of estrogen to hydroxestrogens, known to harbor carcinogenic and pro-lipidemic influences, in skeletal muscle which may also contribute to cardiometabolic disease. Whether targeting CYP1B1 improves cardiometabolic function in obesity remains to be determined. D.W. Stepp and D.J. Fulton are supported by NIH 1R01HL147159. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

DMT1 contributes to MF- 438 - mediated inhibition of glioma cells.

Elevated SCD1 expression has been associated with enhanced cancer cell survival, proliferation, and resistance to therapy in many cancer types including gliomas. Hereby, we investigate the impact of MF-438 on SCD1-mediated lipid metabolism and its consequences on glioma growth and survival. Our data reveals an IDH mut -specific inhibitory effect of MF438 on gliomas. Also, we delineate a dual mechanism of action: while SCD1-mediated lipid metabolism is hindered by MF-438 treatment, MF-438 also exerts an SCD1-independent inhibition on DMT1 expression. Supporting data from the DMT1 blocker underscores its significance in MF-438's anti-glioma efficacy.

PPP2CA Inhibition Promotes Ferroptosis Sensitivity Through AMPK/SCD1 Pathway in Colorectal Cancer.

Colorectal cancer (CRC) is a very common malignancy of the digestive system. Despite a variety of treatments including surgery, chemotherapeutic and targeted drugs, the prognosis for patients with CRC is still unsatisfactory and the mortality remains high. Protein phosphorylation plays an essential role in tumorigenesis and progression and is also crucial for protein to act with proper functions. Ferroptosis is found widely involved in various diseases especially tumors as a newly identified programmed cell death. In our study, we aimed at PPP2CA as a prospective target which may play a crucial role in CRC progression. In one hand, knockdown of PPP2CA significantly enhanced the malignant phenotype in HCT116. In the other hand, knockdown of PPP2CA significantly enhanced Erastin-induced ferroptosis as well. Specifically, knockdown of PPP2CA in HCT116 significantly increased the relative level of malondialdehyde (MDA), reactive oxygen species (ROS) and Fe2+, and decreased GSH/GSSG ratio after the treatment of certain concentration of Erastin. Besides, we found that the inhibition of PPP2CA further led to the suppression of SCD1 expression in CRC cells in a AMPK-dependent way. Ultimately, we conclude that PPP2CA may regulate Erastin-induced ferroptosis through AMPK/SCD1 signaling pathway.