Fatty Acid Oxidation Pathway Research Articles

Glycolysis and Fatty Acid Oxidation Inhibition Improves Survival in Glioblastoma.

Glioblastoma (GBM) is the most aggressive adult glioma with a median survival of 14 months. While standard treatments (safe maximal resection, radiation, and temozolomide chemotherapy) have increased the median survival in favorable O(6)-methylguanine-DNA methyltransferase (MGMT)-methylated GBM (~21 months), a large proportion of patients experience a highly debilitating and rapidly fatal disease. This study examined GBM cellular energetic pathways and blockade using repurposed drugs: the glycolytic inhibitor, namely dicholoroacetate (DCA), and the partial fatty acid oxidation (FAO) inhibitor, namely ranolazine (Rano). Gene expression data show that GBM subtypes have similar glucose and FAO pathways, and GBM tumors have significant upregulation of enzymes in both pathways, compared to normal brain tissue (p < 0.01). DCA and the DCA/Rano combination showed reduced colony-forming activity of GBM and increased oxidative stress, DNA damage, autophagy, and apoptosis in vitro. In the orthotopic Gl261 and CT2A syngeneic murine models of GBM, DCA, Rano, and DCA/Rano increased median survival and induced focal tumor necrosis and hemorrhage. In conclusion, dual targeting of glycolytic and FAO metabolic pathways provides a viable treatment that warrants further investigation concurrently or as an adjuvant to standard chemoradiation for GBM.

Altered lung metabolism and mitochondrial DAMPs in lung injury due to acute kidney injury.

Acute respiratory distress syndrome (ARDS) is a common cause of mortality in patients with acute kidney injury (AKI). Inflammatory crosstalk from the kidney to the lung has been shown to contribute to lung injury after AKI, but anti-inflammatory therapies have not been proven beneficial in human studies. Recently, AKI was shown to alter mitochondria and related metabolic pathways in the heart, but the impact of AKI on lung metabolism has not been investigated to our knowledge. In this study, we evaluated the metabolomic profile of the lung following renal ischemia and reperfusion to identify novel pathways that may be modifiable. We randomized C57BL/6 mice to 20 minutes of bilateral renal arterial clamping or sham operation under ketamine/xylazine anesthesia. At 4 hours after reperfusion, we found a significant increase in markers of lung injury, as well as significant metabolomic changes across lung, kidney, plasma and bronchoalveolar lavage fluid (BALF) compared to shams. Comparative analyses revealed that the fatty acid oxidation pathway was the most significantly altered metabolic pathway, a finding which is consistent with mitochondrial dysfunction systemically and in the lung. These metabolomic changes correlated with the extracellular accumulation of the mitochondrial damage associated molecular patterns (mtDAMPs), mitochondrial DNA (mtDNA) and transcription factor A, mitochondria (TFAM). Finally, we found that intraperitoneal injection of renal mtDAMPs caused metabolomic changes consistent with mitochondrial dysfunction in the lung in vivo. Mitochondrial function and mtDAMPs warrant further investigation as potential therapeutic targets in preventing lung injury because of AKI.

Effects of starvation stress on jade perch scortum barcoo based on proteomics analysis

Proteins related to antioxidant defence systems and energy maintenance play a vital role in resisting starvation in fish. However, studies on the underlying molecular mechanism of starvation stress in the jade perch Scortum barcoo are very limited. Thus, the proteomic changes in S. barcoo during fasting were investigated by stable isotope labelling and high-performance liquid chromatography-tandem mass spectrometry (iTRAQ-LC- MS/MS) in the present study. Therefore, a total of 3324 proteins were identified, including 134 that were significantly altered (p < 0.05, fold change >1.20 or <0.83) in the experimental groups compared with the control group. Among all the differentially expressed proteins, only protein-disulphide reductase (TXNDC12) was upregulated. One-third of the differentially expressed proteins were enriched in the amino acid metabolism pathway, tricarboxylic acid (TCA) cycle pathway, fatty acid metabolism pathway and oxidative phosphorylation pathway. Proteins differentially expressed in the experimental group, including AASS, OGDH, ACAD8, FAH, BHMT, AOC3, AOC2 and HIBADH, are components of pathways that control the metabolism of amino acids. The results suggested the involvement of antioxidant defence in the response to an oxidative imbalance, and GSH, SOD and AKP were regulated under conditions of starvation stress. In conclusion, the data indicated that starvation-induced changes in protein levels that might affect metabolism and the antioxidant system.

CDK4/6 Inhibition Reprograms Mitochondrial Metabolism in BRAFV600 Melanoma via a p53 Dependent Pathway

Simple SummaryCyclin-dependent kinases 4 and 6 (CDK4/6) are key enzymes controlling the cell cycle. CDK4/6 inhibitors are being tested in multiple clinical trials for a range of cancers including melanoma, and a deeper understanding of how they interact with other therapies is vital for their clinical development. Beyond the cell cycle, CDK4/6 regulates cell metabolism, which is a critical factor determining response to standard-of-care mitogen-activated protein kinase (MAPK) pathway therapies in melanoma. Here, we show that CDK4/6 inhibitors increase glutamine and fatty acid-oxidation-dependent mitochondrial metabolism in melanoma cells, but they do not alter the metabolic response to MAPK inhibitors. These observations shed light on how CDK4/6 inhibitors impinge on the regulation of metabolism and how they interact with other therapies in the setting of melanoma.Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors are being tested in numerous clinical trials and are currently employed successfully in the clinic for the treatment of breast cancers. Understanding their mechanism of action and interaction with other therapies is vital in their clinical development. CDK4/6 regulate the cell cycle via phosphorylation and inhibition of the tumour suppressor RB, and in addition can phosphorylate many cellular proteins and modulate numerous cellular functions including cell metabolism. Metabolic reprogramming is observed in melanoma following standard-of-care BRAF/MEK inhibition and is involved in both therapeutic response and resistance. In preclinical models, CDK4/6 inhibitors overcome BRAF/MEK inhibitor resistance, leading to sustained tumour regression; however, the metabolic response to this combination has not been explored. Here, we investigate how CDK4/6 inhibition reprograms metabolism and if this alters metabolic reprogramming observed upon BRAF/MEK inhibition. Although CDK4/6 inhibition has no substantial effect on the metabolic phenotype following BRAF/MEK targeted therapy in melanoma, CDK4/6 inhibition alone significantly enhances mitochondrial metabolism. The increase in mitochondrial metabolism in melanoma cells following CDK4/6 inhibition is fuelled in part by both glutamine metabolism and fatty acid oxidation pathways and is partially dependent on p53. Collectively, our findings identify new p53-dependent metabolic vulnerabilities that may be targeted to improve response to CDK4/6 inhibitors.

Punicalagin Prevents Hepatic Steatosis through Improving Lipid Homeostasis and Inflammation in Liver and Adipose Tissue and Modulating Gut Microbiota in Western Diet-Fed Mice.

Punicalagin (PU)-rich pomegranate peel extract has been shown before to exert protective effects against high fat-induced hepatic damage. The aim of this study is to explore whether and how PU antagonizes hepatic steatosis in Western diet-fed (WD) mice. Mice are fed either chow diet, WD (containing 42% fat, 15% protein, and 43% carbohydrates), or WD supplemented with PU (50mg kg-1 body weight/day) for 13 weeks. Weight gain, hepatic fat content, and inflammation in the liver and adipose tissues are measured. Compared to the WD group, PU-treated mice have lower fat content, decreased levels of alanine transaminase, and inflammation in liver. PU also changed the transcriptional expression of important genes in fatty acid oxidation pathway and alleviated glucose intolerance. Furthermore, PU improved adiponectin signaling and lipid metabolism in visceral adipose tissue. Moreover, PU improved gut microbiota dysbiosis induced by WD and enhanced gut barrier function. The findings suggest that PU improves hepatic steatosis induced by WD, in part through regulating lipid homeostasis and inflammation in liver and adipose tissue and restoring microbiota shift and impaired gut barrier function. Thus, PU can be potentially developed as a potential prevention strategy in combating nonalcoholic fatty liver disease.

Genome-wide identification and classification of Lipoxygenase gene family and their roles in sorghum-aphid interaction.

This report shows detailed characterization of LOX gene family in sorghum and provides new insight of sorghum LOX genes in genetic structure and their roles in plant response to infestation by sugarcane aphids. Lipoxygenases (LOXs) are monomeric, nonheme iron-containing dioxygenases that initiate the fatty acid oxidation pathway creating oxylipins and plant hormone jasmonate both have a key role in plant development and defense. To date, a comprehensive and systematic analysis of sorghum LOXs is still deficient. Thus, we performed a genome-wide analysis of the sorghum LOXs genome and identified nine LOXs genes. Detailed examination of protein sequences and phylogenetic analysis categorized the sorghum LOXs into two subclasses, 9-LOXs (SbLOX1, SbLOX3, SbLOX4, SbLOXm, and SbLOXo), 13-LOXs (SbLOX9, SbLOX5, and SbLOX2), and the unclassified SbLOX8. This classification was further supported by sequence similarity/identity matrix and subcellular localization analysis. The lipoxygenase domains, motifs, and vital amino acids were highly conserved in all sorghum LOX genes. In silico analysis of the promoter region of SbLOXs identified different hormones responsive cis-elements. Furthermore, to explore the roles of sorghum LOXs during sugarcane aphid feeding and exogenous MeJA application, expression analysis was conducted for all the eight LOXs in resistant (Tx2783) and susceptible (Tx7000) sorghum lines, respectively. As detailed in this report, the data generated from both genome-wide identification and expression analysis of lipoxygenase genes suggest the putative functions of two 13-LOXs (SbLOX9 and SbLOX5) and three 9-LOXs (SbLOX1, SbLOX3, and SbLOXo) in biosynthesis of jasmonic acid, green leaf volatiles and death acids, and all of them are involved in defense-related functions in plants. Furthermore, this report represents the first genome-wide analysis of the LOX gene family in sorghum, which will facilitate future studies to characterize the roles of each individual LOXs gene in aphid resistance and defense responses to other stresses.

Ct-OATP1B3 Promotes Epithelial Ovarian Cancer Metastasis Via Regulation of Mitochondrial Fatty Acid Oxidation and Oxidative Phosphorylation

Cancer-type organic anion transporting polypeptide 1B3 (Ct-OATP1B3) is a newly discovered mRNA variant of OATP1B3, which predominantly expresses in various types of cancer specimens. However, very little is known about its biological function in cancer so far. Here, we reveal that Ct-OATP1B3 is overexpressed in epithelial ovarian cancer (EOC) tissues and plays a pivotal role in EOC metastasis. Mechanically, Ct-OATP1B3 directly interacts with insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) and activates mitochondrial fatty acid oxidation (FAO) and oxidative phosphorylation (OXPHOS) pathways to facilitate adenosine triphosphate (ATP) production and cellular lamellipodia formation in EOC cells. Our study provides an insight into the function and underlying mechanism of Ct-OATP1B3 in EOC metastasis, and highlights Ct-OATP1B3 as a novel prognostic marker as well as therapeutic target in EOC.

Activation of epigenetic regulator KDM6B by Salmonella Typhimurium enables chronic infections

ABSTRACT Non-typhoidal Salmonella (NTS) infections result in self limiting gastroenteritis except in rare cases wherein manifestations of chronic infections can occur. Strategies employed by Salmonella to thrive in hostile environments of host during chronic infections are complex and multifaceted. In chronic state, a coordinated action of bacterial effectors allows reprogramming of macrophages to M2 subtype and thereby creating a permissible replicative niche. The mechanistic details of these processes are not fully known. In the current study we identified, histone H3-lysine 27 trimethylation (H3K27me3)-specific demethylase, KDM6B to be upregulated in both cell culture and in murine model of Salmonella infection. KDM6B recruitment upon infection exhibited an associated loss of overall H3K27me3 in host cells and was Salmonella SPI1 effectors coordinated. ChIP-qRT-PCR array analysis revealed several new gene promoter targets of KDM6B demethylase activity including PPARδ, a crucial regulator of fatty acid oxidation pathway and Salmonella-persistent infections. Furthermore, pharmacological inhibition of KDM6B demethylase activity with GSKJ4 in chronic Salmonella infection mice model led to a significant reduction in pathogen load and M2 macrophage polarization in peripheral lymphoid organs. The following work thus reveals Salmonella effector-mediated epigenetic reprogramming of macrophages responsible for its long-term survival and chronic carriage.

Systemic Deficiency of GHR in Pigs leads to Hepatic Steatosis via Negative Regulation of AHR Signaling.

Laron syndrome (LS) is an autosomal recessive genetic disease mainly caused by mutations in the human growth hormone receptor (GHR) gene. Previous studies have focused on Ghr mutant mice, but compared with LS patients, Ghr knockout (KO) mice exhibit differential lipid metabolism. To elucidate the relationship between GHR mutation and lipid metabolism, the role of GHR in lipid metabolism was examined in GHR KO pigs and hepatocytes transfected with siGHR. We observed high levels of free fatty acids and hepatic steatosis in GHR KO pigs, which recapitulates the abnormal lipid metabolism in LS patients. RNAseq analysis revealed that genes related to the fatty acid oxidation pathway were significantly altered in GHR KO pigs. AHR, a transcription factor related to lipid metabolism, was significantly downregulated in GHR KO pigs and siGHR-treated human hepatocytes. We found that AHR directly regulated fatty acid oxidation by directly binding to the promoters of ACOX1 and CPT1A and activating their expression. These data indicate that loss of GHR disturbs the ERK-AHR-ACOX1/CPT1A pathway and consequently leads to hepatic steatosis. Our results established AHR as a modulator of hepatic steatosis, thereby providing a therapeutic target for lipid metabolism disorder.

Altered expression level of ACSM5 in breast cancer: An integrative analysis of tissue biomarkers with diagnostic potential

BackgroundAbnormal gene expression levels of enzymes involved in fatty acid synthesis and oxidation pathways in breast cancer have been shown to associate with progression of breast cancer. However, little is known about the significance of alternations in fatty acid activation, as a key step in their metabolism. We aimed to recognize suitable biomarkers indicating the altered activation of fatty acids and examine their differential expression in breast cancer and adjacent normal breast tissue samples. Material and methodsTranscript levels of ACS enzymes were analyzed in TCGA data (RNAseq), breast cancer and normal breast samples by differential gene expression (DGE). Gene set enrichment analysis (GSEA) was performed to highlight the most enriched genes involved in the activation of fatty acids. Bioinformatic analysis was performed for the selection of LncRNAs. Gene expression analyses were performed using quantitative Real-time PCR (qRT-PCR) in breast cancer tissue samples and adjacent normal breast tissue samples. Correlation and survival analyses were performed using R program. ROC curves were created for TCGA and qPCR data to evaluate the prognostic potential of the biomarkers. ResultsGSEA analysis revealed that ACSM5 is highly enriched in normal breast tissue samples compared to breast cancer tissue samples. LINC00265 with highest co-efficient score with ACSM5 was selected for further analyses. The expression level of ACSM5 and LINC00265 positively correlated with each other and were significantly low in breast cancer tissues compared to normal breast tissues. Correlation analysis suggested a positive correlation between ACSM5 and LINC00265 genes. Survival analysis predicted prognostic potential for ACSM5. ROC curve analyses revealed that ACSM5 and LINC00265 can distinguish breast tumor samples from adjacent breast tissues. ConclusionOur study suggests ACSM5 gene as a potential biomarker with prognostic value in detection of altered activation of medium-chain fatty acids in breast cancer. In addition, the positive correlation between ACSM5 and LINC00265 suggests the presence of possible regulatory mechanism between them.

Adeno-associated virus-mediated delivery of anti-miR-199a tough decoys attenuates cardiac hypertrophy by targeting PGC-1alpha

MicroRNAs (miRNAs) are important regulators in the process of cardiac hypertrophy and heart failure. Previous studies have shown that miR-199a is upregulated in pressure-overload cardiac hypertrophy and that inhibition of miR-199a attenuates cardiac hypertrophy in vitro. However, the therapeutic role of anti-miR-199a treatment in the cardiac hypertrophy in vivo model is less known. Here, we show an efficient and useful method to treat mouse cardiac hypertrophy and restore cardiac function through injection of adeno-associated virus (AAV)-mediated anti-miR-199a tough decoys (TuDs). RNA-seq transcriptome analysis indicated that genes related to cytoplasmic translation and mitochondrial respiratory chain complex assembly were upregulated in anti-miR-199a-treated recovered hearts. We further validated that PGC-1α is the direct target of miR-199a involved in the therapeutic effect and the regulation of the PGC-1α/ERRα axis and that the downstream pathway of mitochondrial fatty acid oxidation and oxidative phosphorylation constitute the underlying mechanism of the restored mitochondrial structure and function in our anti-miR-199a-treated mice. Our study highlights the important regulatory role of miR-199a in cardiac hypertrophy and the value of the AAV-mediated miRNA delivery system.

Venetoclax Synergizes with the RNA-Directed Nucleoside Analog 8-Chloro-Adenosine in Acute Myeloid Leukemia in Vitro and In Vivo

Venetoclax Synergizes with the RNA-Directed Nucleoside Analog 8-Chloro-Adenosine in Acute Myeloid Leukemia in Vitro and In Vivo

Metabolome-wide association study of organophosphate pesticide exposure

Background: Organophosphates (OP) are widely used insecticides that acutely inhibit acetylcholinesterase enzyme activity. There is great interest in improving the understanding of molecular mechanisms related to chronic OP exposure induced toxicity. We aim to elucidate metabolomic changes associated with OP exposure using high-resolution metabolomics (HRM).Methods: In a population-based case control study of Parkinson's disease (PD), we retrieved serum samples of 178 controls and assessed ambient OP exposure via residential and workplace proximity to commercial applications for each subject. We used liquid chromatography-high resolution mass spectrometry to obtain untargeted metabolic profiles and partial least squares regression to select metabolic features associated with OP exposure. Pathway analyses were employed to identify biologic pathways related to OP exposure. Confounders including age, race/ethnicity, sex were controlled a prior.Results: In total we extracted 8,615 and 4,124 metabolic features from serum samples in hydrophilic interaction (HILIC) chromatography (positive ion mode) and C18 (negative ion mode) columns, respectively. Controlling for confounding factors, 151 and 50 discriminatory metabolic features (HILIC and C18, respectively) were selected (Variable Importance in Projection (VIP) &gt;= 2). Pathway enrichment analysis for discriminatory features associated with OP indicated that in serum fatty acid oxidation and inflammation related pathways were altered, including arachidonic acid, leukotriene, and prostaglandin pathways.Conclusion: This study finds chronic low-level OP exposure is associated with differential metabolomic profiles in serum. Our study results suggest that long-term sub-acute OP exposure influences metabolites enriched for oxidative stress and inflammation pathways.

IL-10 production by ILC2s requires Blimp-1 and cMaf, modulates cellular metabolism, and ameliorates airway hyperreactivity

Group 2 innate lymphoid cells (ILC2s) are the dominant innate lymphoid cell population in the lungs at steady state, and their release of type 2 cytokines is a central driver in responding eosinophil infiltration and increased airway hyperreactivity. Our laboratory has identified a unique subset of ILC2s in the lungs that actively produce IL-10 (ILC210s). Our aim was to characterize the effector functions of ILC210s in the development and pathology of allergic asthma. IL-4-stimulated ILC210s were isolated to evaluate cytokine secretion, transcription factor signaling, metabolic dependence, and effector functions invitro. ILC210s were also adoptively transferred into Rag2-/-γc-/- mice, which were then challenged with IL-33 and assessed for airway hyperreactivity and lung inflammation. We have determined that the transcription factors cMaf and Blimp-1 regulate IL-10 expression in ILC210s. Strikingly, our results demonstrate that ILC210s can utilize both autocrine and paracrine signaling to suppress proinflammatory ILC2 effector functions invitro. Further, this subset dampens airway hyperreactivity and significantly reduces lung inflammation invivo. Interestingly, ILC210s demonstrated a metabolic dependency on the glycolytic pathway for IL-10 production, shifting from the fatty acid oxidation pathway conventionally utilized for proinflammatory effector functions. These findings provide an important and previously unrecognized role of ILC210s in diseases associated with ILC2s such as allergic lung inflammation and asthma. They also provide new insights into the metabolism dependency of proinflammatory and anti-inflammatory ILC2 phenotypes.

Japanese patients with mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase deficiency: In vitro functional analysis of five novel HMGCS2 mutations.

Mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (HMGCS2) deficiency is a metabolic disorder caused by mutations in the HMGCS2 gene. The present study describes the identification of four cases of HMGCS2 deficiency in Japan. Hepatomegaly and severe metabolic acidosis were observed in all cases. Fatty liver was identified in three cases, which suggested the unavailability of fatty acids. All patients presented with a high C2/C0 ratio, suggesting that the fatty acid oxidation pathway was normal during metabolic crisis. Genetic analyses revealed five rare, novel variants (p.G219E, p.M235T, p.V253A, p.S392L and p.R500C) in HMGCS2. To confirm their pathogenicity, a eukaryotic expression system and a bacterial expression system was adopted that was successfully used to obtain affinity-purified HMGCS2 protein with measurable activity. Purified M235T, S392L and R500C proteins did not retain any residual activity, whilst the V253A variant showed some residual enzymatic activity. Judging from the transient expression experiment in 293T cells, the G219E variant appeared to be unstable. In conclusion, the present study identified five novel variants of HMGCS2 that were indicated to be pathogenic in four patients affected by HMGCS2 deficiency.

An Oil Rich in γ-Linolenic Acid Differently Affects Hepatic Fatty Acid Oxidation in Mice and Rats.

The effects of different dietary fats on hepatic fatty acid oxidation were compared in male ICR mice and Sprague-Dawley rats. Animals were fed diets containing 100 g/kg of either palm oil (saturated fat), safflower oil (rich in linoleic acid), an oil of evening primrose origin (γ-linolenic acid, GLA oil), perilla oil (α-linolenic acid) or fish oil (eicosapentaenoic and doxosahexaenoic acids) for 21 d. GLA, perilla and fish oils, compared with palm and safflower oils, increased the activity of fatty acid oxidation enzymes in both mice and rats, with some exceptions. In mice, GLA and fish oils greatly increased the peroxisomal palmitoyl-CoA oxidation rate, and the activity of acyl-CoA oxidase and enoyl-CoA hydratase to the same degree. The effects were much smaller with perilla oil. In rats, enhancing effects were more notable with fish oil than with GLA and perilla oils, excluding the activity of enoyl-CoA hydratase, and were comparable between GLA and perilla oils. In mice, strong enhancing effects of GLA oil, which were greater than with perilla oil and comparable to those of fish oil, were confirmed on mRNA levels of peroxisomal but not mitochondrial fatty acid oxidation enzymes. In rats, the effects of GLA and perilla oils on mRNA levels of peroxisomal and mitochondrial enzymes were indistinguishable, and lower than those observed with fish oil. Therefore, considerable diversity in the response to dietary polyunsaturated fats, especially the oil rich in γ-linolenic acid and fish oil, of hepatic fatty acid oxidation pathway exists between mice and rats.

Abstract 3723: SIRT1 is a novel therapeutic target in T-ALL

Abstract T-cell acute lymphoblastic leukemia (T-ALL) is a NOTCH1-driven aggressive disease that requires treatment with intensified chemotherapy. Still, 20-50% of patients relapse and ultimately die, highlighting the need to identify novel therapeutic targets. We previously demonstrated the importance of NOTCH1-driven metabolic pathways in the response to anti-NOTCH1 therapies (gamma-secretase inhibitors, GSIs), and identified both glutaminolysis and autophagy as therapeutic targets that are highly synergistic with NOTCH1 inhibition in T-ALL in vivo. Moreover, epigenetic plasticity has also been proposed to mediate resistance to GSIs. Thus, we postulated that central regulators that control both the metabolic and epigenetic status of cells could act as master regulators of NOTCH1-induced transformation and might lead us to the identification of novel therapeutic targets in this disease. In this context, our results have identified the SIRT1 histone deacetylase, a central epigenetic and metabolic regulator, as a key player in T-ALL. Analyses of gene expression profiling data from T-ALL patients revealed a significant upregulation of SIRT1 in T-ALL patients. Consistently, SIRT1 protein levels are significantly upregulated in T-ALL cells as compared to normal human thymus. Next, and to formally test the effects of Sirt1 on T-cell transformation, we generated NOTCH1-driven primary T-ALLs from different Sirt1 genetic backgrounds. In this context, our results demonstrate that Sirt1 genetic overexpression leads to accelerated kinetics of NOTCH1-induced T-ALL and promotes resistance to GSI treatment in T-ALL in vivo in a deacetylase-dependent manner. Conversely, germinal loss of Sirt1 leads to delayed T-ALL development and reduced disease penetrance. Moreover, pharmacological inhibition of SIRT1 with Tenovin-6 shows anti-leukemic and synergistic effects with NOTCH1 inhibition in T-ALL cell lines in vitro. Finally, genetic deletion of Sirt1 in already established primary isogenic Sirt1 conditional knockout leukemias leads to significant and highly synergistic anti-leukemic effects with GSI treatment in vivo, resulting in complete cure of 10% of mice. Mechanistically, acute deletion of Sirt1 leads to broad transcriptional changes characterized by a block in mTOR signaling, suggesting leukemia cells suffer a metabolic crisis upon Sirt1 loss. Consistently, acute deletion of Sirt1 results in prominent global metabolic changes in glycolysis, TCA cycle and fatty acid oxidation pathways. Specifically, Sirt1 loss results in a significant glycolytic block with concomitant activation of AMPK, resulting in markedly cytotoxic effects. Overall, our results reveal SIRT1 as a critical major player in T-ALL; unveil an oncogenic role for Sirt1 in T-ALL generation and progression; demonstrate that Sirt1 mediates resistance to anti-NOTCH1 therapies; and uncover Sirt1 as a novel therapeutic target for the treatment of T-ALL. Citation Format: Olga Lancho, Victoria da Silva-Diz, Shirley Luo, Amarthya Singh, Hossein Khiabanian, Daniel Herranz. SIRT1 is a novel therapeutic target in T-ALL [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3723.

Targeting NFATc4 attenuates non-alcoholic steatohepatitis in mice

The nuclear factor of activated T-cells (NFAT) family was first recognised to play an important role in the differentiation of T cells, but has since been shown to regulate multiple pathophysiological processes. However, whether it is involved in the pathogenesis of non-alcoholic steatohepatitis (NASH) remains unknown. Hepatic NFATc expression and localisation were analysed in C57BL/6 mice on a methionine-choline-deficient diet, as well as in samples from non-alcoholic fatty liver disease patients. Gain- or loss-of-function approaches were used to investigate the role of NFATc4 in NASH. NFATc4 translocates from the cytoplasm to the nucleus in hepatocytes of both humans and rodents with NASH. NFATc4 knockdown resulted in decreased hepatic steatosis, inflammation, and fibrosis during NASH progression. Mechanistically, we found that activated NFATc4 directly bound to peroxisome proliferator-activated receptor α (PPARα) in the nucleus and negatively regulated its transcriptional activity, thereby impairing the hepatic fatty acid oxidation pathway and increasing lipid deposition in the liver. Moreover, NFATc4 activation increased the production and secretion of osteopontin (OPN) from hepatocytes, which subsequently enhanced the macrophage-mediated inflammatory response and hepatic stellate cell-mediated fibrosis progression via paracrine signalling. Hepatic NFATc4 activation accelerates the progression of NASH by suppressing PPARα signalling and increasing OPN expression. Genetic or pharmacological inhibition of NFATc4 may have potential for future therapy of NASH. NFATc4 is activated in the non-alcoholic steatohepatitis of mice and patients. Inhibition of NFATc4 activation alleviates lipid deposition, inflammatory response, and fibrosis progression in the liver.

Cerebellar mitochondrial dysfunction and concomitant multi-system fatty acid oxidation defects are sufficient to discriminate PTSD-like and resilient male mice

The impact of trauma on mental health is complex with poorly understood underlying mechanisms. Mitochondrial dysfunction is increasingly implicated in psychopathologies and mood disorders, including post-traumatic stress disorder (PTSD). We hypothesized that defects in mitochondrial energy metabolism in the cerebellum, an emerging region of interest in the pathobiology of mood disorders, would be associated with PTSD-like symptomatology, and that PTSD-like symptomatology would correlate with the activities of the mitochondrial electron transport chain (mtETC) and fatty acid oxidation (FAO) pathways. We assayed mitochondrial energy metabolism and fatty acid profiling using targeted metabolomics in mice exposed to a recently developed paradigm for PTSD-induction. 48 wild type male FVB.129P2 mice were exposed to a trauma, and PTSD-like and resilient animals were identified using behavioral profiling. Mice displaying PTSD-like symptomatology displayed reduced mtETC complex activities in the cerebellum, and cerebellar mtETC complex activity negatively correlated with PTSD-like symptomatology. PTSD-like animals also displayed fatty acid profiles consistent with FAO dysfunction in both cerebellum and plasma. Machine learning analysis of all biochemical measures in this cohort of animals also identified plasma acetylcarnitine, along with reduced activity of cerebellar complex I and IV as well as succinate:cytochrome c oxidoreductase as state predictive discriminators of PTSD-symptomatology. Our data also suggest that trauma-induced impaired mtETC function in the cerebellum and concomitant impaired multi-system fatty acid oxidation are candidate drivers of PTSD-like behavior in mice. These bioenergetic and metabolic changes may offer an informative window into the underlying biology and highlight novel potential targets for diagnostics and therapeutic interventions in PTSD.

TGF‑β1‑induced epithelial‑mesenchymal transition increases fatty acid oxidation and OXPHOS activity via the p‑AMPK pathway in breast cancer cells

Breast cancer is the most common malignancy in women, and metastasis is the leading cause of death in breast cancer patients. Previous studies have shown that epithelial‑mesenchymal transition (EMT) is involved in the metastasis of breast cancer, but the metabolic reprogramming and regulation mechanisms involved in the EMT process are still unclear. In the present study, we successfully constructed an EMT cell model induced by transforming growth factor β1 (TGF‑β1) treatment of MCF‑7 cells at different times. The results showed that cell adhesion decreased, cell invasion increased and ATP levels increased in EMT MCF‑7 cells treated with TGF‑β1. Furthermore, the expression of fatty acid synthase (FASN) was decreased, and the expression of key fatty acid β‑oxidation enzymes (CPT1 and CD36) was elevated in treated cells compared to control cells. These results showed that the fatty acid oxidation pathway was enhanced. In addition, the expression of NADH:ubiquinone oxidoreductase subunit B8 (NDUFB8), mitochondrial transcription factor A (TFAM) and cytochrome c oxidase subunit I (COXI) increased, and the mitochondrial DNA copy number and ROS levels were also significantly increased during TGF‑β1‑induced EMT. These results indicated that mitochondrial oxidative phosphorylation (OXPHOS) activity was enhanced during EMT. In addition, we observed that the expression of p‑AMPK was increased and ACC (Acetyl‑CoA Carboxylase) was decreased during TGF‑β1‑induced EMT in MCF‑7 cells. Immunohistochemical analysis of clinical samples revealed high expression of FASN in epithelial cells that had high expression of E‑cadherin, while high expression of CPT‑1 was observed in mesenchymal cells that had high expression of vimentin. Results of the current study showed a metabolic transition in TGF‑β1‑induced EMT in MCF‑7 cells. This transition may regulate fatty acid oxidation and OXPHOS activity in EMT MCF‑7 cells through the p‑AMPK pathway. These data suggest that a metabolic transition that suppresses lipogenesis and favors energy production is an essential component of TGF‑β1‑induced EMT and metastasis in breast cancer. This study thus provides a new strategy for identifying new therapeutic targets for breast cancer.