Changes In Metabolic Gene Expression Research Articles

The C. elegans Myc-family of transcription factors coordinate a dynamic adaptive response to dietary restriction.

Dietary restriction (DR), the process of decreasing overall food consumption over an extended period of time, has been shown to increase longevity across evolutionarily diverse species and delay the onset of age-associated diseases in humans. In Caenorhabditis elegans, the Myc-family transcription factors (TFs) MXL-2 (Mlx) and MML-1 (MondoA/ChREBP), which function as obligate heterodimers, and PHA-4 (orthologous to FOXA) are both necessary for the full physiological benefits of DR. However, the adaptive transcriptional response to DR and the role of MML-1::MXL-2 and PHA-4 remains elusive. We identified the transcriptional signature of C. elegans DR, using the eat-2 genetic model, and demonstrate broad changes in metabolic gene expression in eat-2 DR animals, which requires both mxl-2 and pha-4. While the requirement for these factors in DR gene expression overlaps, we found many of the DR genes exhibit an opposing change in relative gene expression in eat-2;mxl-2 animals compared to wild-type, which was not observed in eat-2 animals with pha-4 loss. Surprisingly, we discovered more than 2000 genes synthetically dysregulated in eat-2;mxl-2, out of which the promoters of down-regulated genes were substantially enriched for PQM-1 and ELT-1/3 GATA TF binding motifs. We further show functional deficiencies of the mxl-2 loss in DR outside of lifespan, as eat-2;mxl-2 animals exhibit substantially smaller brood sizes and lay a proportion of dead eggs, indicating that MML-1::MXL-2 has a role in maintaining the balance between resource allocation to the soma and to reproduction under conditions of chronic food scarcity. While eat-2 animals do not show a significantly different metabolic rate compared to wild-type, we also find that loss of mxl-2 in DR does not affect the rate of oxygen consumption in young animals. The gene expression signature of eat-2 mutant animals is consistent with optimization of energy utilization and resource allocation, rather than induction of canonical gene expression changes associated with acute metabolic stress, such as induction of autophagy after TORC1 inhibition. Consistently, eat-2 animals are not substantially resistant to stress, providing further support to the idea that chronic DR may benefit healthspan and lifespan through efficient use of limited resources rather than broad upregulation of stress responses, and also indicates that MML-1::MXL-2 and PHA-4 may have distinct roles in promotion of benefits in response to different pro-longevity stimuli.

Abstract 1270: ECHS1 mediates metabolic disruption in hormone receptor-positive breast tumor microenvironment

Abstract Unchecked hyperadiposity causes systemic metabolic perturbations and subclinical chronic inflammation, promoting hormone receptor positive (HR+) breast cancer. Murine models of high-fat diet-induced obesity have shown alterations in proteins involved in fatty acid binding and mitochondrial beta-oxidation, including enoyl-CoA hydratase short chain 1 (ECHS1), which promote increased uptake of fatty acids by primary tumor cells. This creates a metabolic tug of war between tumor and immune cells in the tumor microenvironment, thereby depriving cytotoxic immune cells of the metabolic reprogramming for anti-tumor functionality. Nonetheless, metabolic gene expression changes in breast tumor microenvironment of obese individuals remain elusive. We hypothesize that increased expression of ECHS1 leads to immune dysregulation in breast tumor microenvironment and increases risk of cancer progression. Proteomic and genomic expression and survival characteristics of ECHS1 in invasive breast cancer was explored in The Cancer Genome Atlas (TCGA) and the Clinical Proteomic Tumor Analysis Consortium. We the modeled the effects of ECHS1 expression on immune infiltration in the tumor microenvironment using a regression framework. We also performed single cell RNA sequencing analysis for differential expression of ECHS1 in various human breast cells. Additionally, expression level of ECHS1 was validated in silico in adipose tissue to elucidate increased immune dysregulation and risk of progression of breast carcinoma in obese individuals. We found a significantly increased expression of ECHS1 at both RNA and protein levels in HR+ breast cancer (p<0.001 for both), compared to Herceptin 2 receptor-positive or triple negative breast cancer. High expression of ECHS1 in female breast cancer is also associated with significantly decreased survival based on the TCGA data. Further, we found a significantly negative correlation of CD8+ T cells, neutrophils, and macrophages, and a significantly positive correlation of regulatory T cells with ECHS1 expression in the breast tumor microenvironment. We discovered increased expression of ECHS1 in luminal epithelial cells compared to myoepithelial cells based on single cell RNA sequencing. Lastly, high expression of ECHS1 protein expression based on immunohistochemistry was confirmed in human adipocytes. Collectively, our observations support the hypothesis that preferential uptake of free fatty acid through increased expression of ECHS1 in HR+ breast cancer impairs cytotoxic and anti-tumor effects of CD8+ T cells in the tumor microenvironment. Immune dysregulation is further amplified in obese individuals given increased levels of adipose cells and higher ECHS1 expression. Altogether, ECHS1 is a putative biomarker and potential therapeutic target as its downregulation may improve survival in obese patients with HR+ breast cancer. Citation Format: Tina Bharani, Divyansh Agarwal, Estefania Roldan-Vasquez, Jessalyn Ubellacker, Ted A. James. ECHS1 mediates metabolic disruption in hormone receptor-positive breast tumor microenvironment [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 1270.

Voluntary Wheel Running Exercise Does Not Attenuate Circadian and Cardiac Dysfunction Caused by Conditional Deletion of Bmal1.

Circadian misalignment occurs with age, jet lag, and shift work, leading to maladaptive health outcomes including cardiovascular diseases. Despite the strong link between circadian disruption and heart disease, the cardiac circadian clock is poorly understood, prohibiting identification of therapies to restore the broken clock. Exercise is the most cardioprotective intervention identified to date and has been suggested to reset the circadian clock in other peripheral tissues. Here, we tested the hypothesis that conditional deletion of core circadian gene Bmal1 would disrupt cardiac circadian rhythm and function and that this disruption would be ameliorated by exercise. To test this hypothesis, we generated a transgenic mouse with spatial and temporal deletion of Bmal1 only in adult cardiac myocytes (Bmal1 cardiac knockout [cKO]). Bmal1 cKO mice demonstrated cardiac hypertrophy and fibrosis concomitant with impaired systolic function. This pathological cardiac remodeling was not rescued by wheel running. While the molecular mechanisms responsible for the profound cardiac remodeling are unclear, it does not appear to involve activation of the mammalian target of rapamycin (mTOR) signaling or changes in metabolic gene expression. Interestingly, cardiac deletion of Bmal1 disrupted systemic rhythms as evidenced by changes in the onset and phasing of activity in relationship to the light/dark cycle and by decreased periodogram power as measured by core temperature, suggesting cardiac clocks can regulate systemic circadian output. Together, we suggest a critical role for cardiac Bmal1 in regulating both cardiac and systemic circadian rhythm and function. Ongoing experiments will determine how disruption of the circadian clock causes cardiac remodeling in an effort to identify therapeutics to attenuate the maladaptive outcomes of a broken cardiac circadian clock.

Adaptations of key metabolic pathways in primary and metastatic epithelial ovarian cancer (253)

Objectives: Patients with ovarian cancer (OC) often present with advanced-stage disease at diagnosis; however, the molecular mechanisms which drive the aggressive nature of OC metastases have not been well characterized. Metastasizing cancer cells undergo metabolic reprogramming to utilize available lipids in the metastatic niche of the omentum. This study aimed to understand the compensatory metabolic mechanisms that enable this OC metastasis. Our work focused on understanding the contributions of the pentose phosphate pathway (PPP)—a key mechanism responsible for redox homeostasis—in enabling this evolution. Methods: Using gene expression data of matched human primary and omental tumor samples (n=30), we performed targeted analysis of metabolic gene expression changes, which revealed upregulation of the PPP in omental metastases. We then performed in vitro and in vivo experiments using pre-clinical ovarian cancer models (SKOV3, IGROV, HEYA8). Given the canonical role of the PPP in maintaining redox homeostasis, we assessed oxidative stress in organoid cultures from omental metastases harvested at mouse necropsy and in cultures grown in omental conditioned media. Inhibition of the rate-limiting enzyme of the PPP, glucose-6-phosphate dehydrogenase (G6PD), was performed via shRNA knockdowns and treated with a pharmacological inhibitor. HeyA8 tumor-bearing mice were treated with the G6PD inhibitor, and the metastatic burden was evaluated using IVIS during treatment and in peritoneal organs following the sacrifice. Statistical significance was established using unpaired two-tailed Student’s t-tests. Results: Differential analysis of metabolic gene expression and pathway analysis revealed upregulation of the PPP in omental metastases compared to primary ovarian tumors (p<0.05, EnrichR Score = 800). Primary tumors and omental metastases were harvested from SKOV3, HeyA8, and IGROV1 tumor-bearing mice at necropsy and used to establish organoids. DCFH-DA, a fluorogenic probe for ROS, measured higher levels of oxidative stress in metastatic organoids than primary tumors (normalized F525= 11.3623, p<0.0005). SKOV3 organoids expressing HyPer, a ratiometric biosensor of intracellular H2O2, exhibited higher oxidative stress when grown in omental conditioned media versus basal organoid media (normalized F420/F500=1.27, p<0.05). Pharmacological and shRNA inhibition of G6PD sensitized cells to oxidative stress, reducing cell viability in vitro (p<0.05). Treatment with a G6PD inhibitor in vivo significantly decreased tumor growth and metastases compared to vehicle treatment (p<0.005). Objectives: Patients with ovarian cancer (OC) often present with advanced-stage disease at diagnosis; however, the molecular mechanisms which drive the aggressive nature of OC metastases have not been well characterized. Metastasizing cancer cells undergo metabolic reprogramming to utilize available lipids in the metastatic niche of the omentum. This study aimed to understand the compensatory metabolic mechanisms that enable this OC metastasis. Our work focused on understanding the contributions of the pentose phosphate pathway (PPP)—a key mechanism responsible for redox homeostasis—in enabling this evolution. Methods: Using gene expression data of matched human primary and omental tumor samples (n=30), we performed targeted analysis of metabolic gene expression changes, which revealed upregulation of the PPP in omental metastases. We then performed in vitro and in vivo experiments using pre-clinical ovarian cancer models (SKOV3, IGROV, HEYA8). Given the canonical role of the PPP in maintaining redox homeostasis, we assessed oxidative stress in organoid cultures from omental metastases harvested at mouse necropsy and in cultures grown in omental conditioned media. Inhibition of the rate-limiting enzyme of the PPP, glucose-6-phosphate dehydrogenase (G6PD), was performed via shRNA knockdowns and treated with a pharmacological inhibitor. HeyA8 tumor-bearing mice were treated with the G6PD inhibitor, and the metastatic burden was evaluated using IVIS during treatment and in peritoneal organs following the sacrifice. Statistical significance was established using unpaired two-tailed Student’s t-tests. Results: Differential analysis of metabolic gene expression and pathway analysis revealed upregulation of the PPP in omental metastases compared to primary ovarian tumors (p<0.05, EnrichR Score = 800). Primary tumors and omental metastases were harvested from SKOV3, HeyA8, and IGROV1 tumor-bearing mice at necropsy and used to establish organoids. DCFH-DA, a fluorogenic probe for ROS, measured higher levels of oxidative stress in metastatic organoids than primary tumors (normalized F525= 11.3623, p<0.0005). SKOV3 organoids expressing HyPer, a ratiometric biosensor of intracellular H2O2, exhibited higher oxidative stress when grown in omental conditioned media versus basal organoid media (normalized F420/F500=1.27, p<0.05). Pharmacological and shRNA inhibition of G6PD sensitized cells to oxidative stress, reducing cell viability in vitro (p<0.05). Treatment with a G6PD inhibitor in vivo significantly decreased tumor growth and metastases compared to vehicle treatment (p<0.005).

CD5 Deficiency Alters Helper T Cell Metabolic Function and Shifts the Systemic Metabolome.

Metabolic function plays a key role in immune cell activation, destruction of foreign pathogens, and memory cell generation. As T cells are activated, their metabolic profile is significantly changed due to signaling cascades mediated by the T cell receptor (TCR) and co-receptors found on their surface. CD5 is a T cell co-receptor that regulates thymocyte selection and peripheral T cell activation. The removal of CD5 enhances T cell activation and proliferation, but how this is accomplished is not well understood. We examined how CD5 specifically affects CD4+ T cell metabolic function and systemic metabolome by analyzing serum and T cell metabolites from CD5WT and CD5KO mice. We found that CD5 removal depletes certain serum metabolites, and CD5KO T cells have higher levels of several metabolites. Transcriptomic analysis identified several upregulated metabolic genes in CD5KO T cells. Bioinformatic analysis identified glycolysis and the TCA cycle as metabolic pathways promoted by CD5 removal. Functional metabolic analysis demonstrated that CD5KO T cells have higher oxygen consumption rates (OCR) and higher extracellular acidification rates (ECAR). Together, these findings suggest that the loss of CD5 is linked to CD4+ T cell metabolism changes in metabolic gene expression and metabolite concentration.

Isonitrogenous low-carbohydrate diet elicits specific changes in metabolic gene expression in the skeletal muscle of exercise-trained mice.

With the renewed interest in low-carbohydrate diets (LCDs) in the sports field, a few animal studies have investigated their potential. However, most rodent studies have used an LCD containing low protein, which does not recapitulate a human LCD, and the muscle-specific adaptation in response to an LCD remains unclear. Therefore, we investigated the effects of two types of LCDs, both containing the same proportion of protein as a regular diet (isonitrogenous LCD; INLCD), on body composition, exercise performance, and metabolic fuel selection at the genetic level in the skeletal muscles of exercise-trained mice. Three groups of mice (n = 8 in each group), one fed a regular AIN-93G diet served as the control, and the others fed either of the two INLCDs containing 20% protein and 10% carbohydrate (INLCD-10%) or 20% protein and 1% carbohydrate (INLCD-1%) had a regular exercise load (5 times/week) for 12 weeks. Body weight and muscle mass did not decrease in either of the INLCD-fed groups, and the muscle glycogen levels and endurance capacity did not differ among the three groups. Only in the mice fed INLCD-1% did the plasma ketone concentration significantly increase, and gene expression related to glucose utilization significantly declined in the muscles. Both INLCD-1% and INLCD-10% consumption increased gene expression related to lipid utilization. These results suggest that, although INLCD treatment did not affect endurance capacity, it helped maintain muscle mass and glycogen content regardless of the glucose intake restrictions in trained mice. Moreover, an INLCD containing a low carbohydrate content might present an advantage by increasing lipid oxidation without ketosis and suppressing muscle glucose utilization.

TAMI-26. INVESTIGATING TUMOR MICROENVIRONMENT METABOLIC DEPENDENCIES IN GLIOBLASTOMA

Abstract Metabolic reprogramming is a hallmark of cancer. Malignant cells must acquire metabolic adaptations in response to a multitude of intrinsic and extrinsic factors to fuel neoplastic progression. Mutations or changes in metabolic gene expression can impose nutrient dependencies in tumors, and even in the absence of metabolic defects, cancer cells can become auxotrophic for particular nutrients or metabolic byproducts generated by other cells in the tumor microenvironment (TME). Altered metabolism in GBM is becoming an increasingly promising area of research to identify novel therapeutic targets and biomarkers, as metabolic rewiring can occur across numerous genotypes. The unique features of the brain TME pose a difficult challenge when studying GBM and other primary brain cancers – currently, the availability of nutrients in the brain, as well as how they influence or are influenced by tumor metabolism, are not well understood. Our group has identified a subgroup of gliomas, hereafter termed TME-dependent, which can only form tumors in the brain TME. While genetically heterogeneous, these tumors share transcriptional identities linked to oligodendrocyte precursor cell (OPC) and neuronal lineages. Systematic molecular profiling of over 75 patient tumors and their matched cell culture and brain orthotopic xenograft derived models revealed that TME-dependent tumors display lipid metabolic signatures linked to signaling and interactions with surrounding neurons and glial cells. Collectively, these data emphasize the metabolic heterogeneity within GBM, and reveal a subset of gliomas that lack metabolic plasticity in fatty acid biosynthetic programs, indicating a potential brain-microenvironment specific metabolic dependency linked to transcriptional identity that can be targeted for therapy.

ETMM-02. PRECLINICAL MODELS REVEAL BRAIN-MICROENVIRONMENT SPECIFIC METABOLIC DEPENDENCIES IN GLIOBLASTOMA

Metabolic reprogramming is a hallmark of cancer, and malignant cells must acquire metabolic adaptations in response to a multitude of intrinsic and extrinsic factors to fuel neoplastic progression. Mutations or changes in metabolic gene expression can impose nutrient dependencies in tumors, and even in the absence of metabolic defects, cancer cells can become auxotrophic for particular nutrients or metabolic byproducts generated by other cells in the tumor microenvironment (TME). Conventional cell lines do not recapitulate the metabolic heterogeneity of glioblastoma (GBM), while primary cultured cells do not account for the influences of the microenvironment and the blood brain barrier on tumor biology. Additionally, these systems are under strong selective pressure divergent from that in vivo, leading to reduced heterogeneity between cultured tumor cells. Here, we describe a biobank of direct-from-patient derived orthotopic xenografts (GliomaPDOX) and gliomaspheres that reveal a subset of gliomas that, while able to form in vivo, cannot survive in vitro. RNA sequencing of tumors that can form both in vivo and in vitro (termed “TME-Indifferent”) compared to that of tumors that can only form in vivo (termed “TME-Dependent”) revealed transcriptional changes associated with altered nutrient availability, emphasizing the unique metabolic programs impacted by the tumor microenvironment. Furthermore, TME-dependent tumors lack metabolic signatures associated with nutrient biosynthesis, thus indicating a potential dependency of these tumors on scavenging specific nutrients from the extracellular milieu. Collectively, these data emphasize the metabolic heterogeneity within GBM and reveal a subset of gliomas that lack metabolic plasticity, indicating a potential brain-microenvironment specific metabolic dependency that can be targeted for therapy.

Nuclear translocation ability of Lipin differentially affects gene expression and survival in fed and fasting Drosophila

Lipins are eukaryotic proteins with functions in lipid synthesis and the homeostatic control of energy balance. They execute these functions by acting as phosphatidate phosphatase enzymes in the cytoplasm and by changing gene expression after translocation into the cell nucleus, in particular under fasting conditions. Here, we asked whether nuclear translocation and the enzymatic activity of Drosophila Lipin serve essential functions and how gene expression changes, under both fed and fasting conditions, when nuclear translocation is impaired. To address these questions, we created a Lipin null mutant, a mutant expressing Lipin lacking a nuclear localization signal (LipinΔNLS ), and a mutant expressing enzymatically dead Lipin. Our data support the conclusion that the enzymatic but not nuclear gene regulatory activity of Lipin is essential for survival. Notably, adult LipinΔNLS flies were not only viable but also exhibited improved life expectancy. In contrast, they were highly susceptible to starvation. Both the improved life expectancy in the fed state and the decreased survival in the fasting state correlated with changes in metabolic gene expression. Moreover, increased life expectancy of fed flies was associated with a decreased metabolic rate. Interestingly, in addition to metabolic genes, genes involved in feeding behavior and the immune response were misregulated in LipinΔNLS flies. Altogether, our data suggest that the nuclear activity of Lipin influences the genomic response to nutrient availability with effects on life expectancy and starvation resistance. Thus, nutritional or therapeutic approaches that aim at lowering nuclear translocation of lipins in humans may be worth exploring.

TAMI-06. PRECLINICAL MODELS REVEAL BRAIN-MICROENVIRONMENT SPECIFIC METABOLIC DEPENDENCIES IN GLIOBLASTOMA

Abstract Metabolic reprogramming is a hallmark of cancer, and malignant cells must acquire metabolic adaptations to fuel neoplastic progression. Mutations or changes in metabolic gene expression can impose nutrient dependencies in tumors, and even in the absence of metabolic defects, cancer cells can become auxotrophic for particular nutrients or metabolic byproducts generated by other cells in the tumor microenvironment (TME). Conventional cell lines do not recapitulate the metabolic heterogeneity of glioblastoma (GBM), while primary cultured cells do not account for the influences of the microenvironment and the blood brain barrier on tumor biology. Additionally, these systems are under strong selective pressure divergent from that in vivo, leading to reduced heterogeneity between cultured tumor cells. Here, we describe a biobank of direct-from-patient derived orthotopic xenografts (GliomaPDOX) and gliomaspheres that reveal a subset of gliomas that, while able to form in vivo, cannot survive in vitro. RNA sequencing of tumors that can form both in vivo and in vitro (termed “TME-Indifferent”) compared to that of tumors that can only form in vivo (termed “TME-Dependent”) revealed transcriptional changes associated with altered nutrient availability, emphasizing the unique metabolic programs impacted by the tumor microenvironment. Furthermore, TME-dependent tumors lack metabolic signatures associated with nutrient biosynthesis, thus indicating a potential dependency of these tumors on scavenging specific nutrients from the extracellular milieu. Collectively, these data emphasize the metabolic heterogeneity within GBM, and reveal a subset of gliomas that lack metabolic plasticity, indicating a potential brain-microenvironment specific metabolic dependency that can be targeted for therapy.

Alzheimer's Disease: Protective Effects of Mycobacterium vaccae, a Soil-Derived Mycobacterium with Anti-Inflammatory and Anti-Tubercular Properties, on the Proteomic Profiles of Plasma and Cerebrospinal Fluid in Rats.

Alzheimer's disease (AD) is an inflammatory neurodegenerative disease that may be associated with prior bacterial infections. Microbial "old friends" can suppress exaggerated inflammation in response to disease-causing infections or increase clearance of pathogens such as Mycobacterium tuberculosis, which causes tuberculosis (TB). One such "old friend" is Mycobacterium vaccae NCTC 11659, a soil-derived bacterium that has been proposed either as a vaccine for prevention of TB, or as immunotherapy for the treatment of TB when used alongside first line anti-TB drug treatment. The goal of this study was to use a hypothesis generating approach to explore the effects of M. vaccae on physiological changes in the plasma and cerebrospinal fluid (CSF). Liquid chromatography-tandem mass spectrometry-based proteomics were performed in plasma and CSF of adult male rats after immunization with a heat-killed preparation of M. vaccae NCTC 11659 or borate-buffered saline vehicle. Gene enrichment analysis and analysis of protein-protein interactions were performed to integrate physiological network changes in plasma and CSF. We used RT-qPCR to assess immune and metabolic gene expression changes in the hippocampus. In both plasma and CSF, immunization with M. vaccae increased proteins associated with immune activation and downregulated proteins corresponding to lipid (including phospholipid and cholesterol) metabolism. Immunization with M. vaccae also increased hippocampal expression of interleukin-4 (IL-4) mRNA, implicating anti-inflammatory effects in the central nervous system. M. vaccae alters host immune activity and lipid metabolism. These data are consistent with the hypothesis that microbe-host interactions may protect against possible infection-induced, inflammation-related cognitive impairments.

Vitamin D regulation of HAS2, hyaluronan synthesis and metabolism in triple negative breast cancer cells

The vitamin D receptor (VDR) and its ligand 1,25(OH)2D3 (1,25D) exert anti-tumor effects, but considerable heterogeneity has been reported in different model systems. In general, cell lines derived from aggressive tumor subtypes such as Triple Negative Breast Cancer (TNBC) express low levels of VDR and are less sensitive to 1,25D than those derived from more differentiated tumor types. We have previously reported that 1,25D inhibits hyaluronic acid synthase 2 (HAS2) expression and hyaluronic acid (HA) synthesis in murine TNBC cells. Here we confirmed the inhibitory effect of 1,25D on HA synthesis in human Hs578T cells representative of the mesenchymal/stem-like (MSL) subtype of TNBC. Because HA synthesis requires the production of hexoses for incorporation into HA, we predicted that the high HA production characteristic of Hs578T cells would require sustained metabolic changes through the hexosamine biosynthetic pathway (HBP). We thus examined metabolic gene expression in Hs578T cell variants sorted for High (HAHigh) and Low (HALow) HA production, and the ability of 1,25D to reverse these adaptive changes. HAHigh populations exhibited elevated HA production, smaller size, increased proliferation and higher motility than HALow populations. Despite their more aggressive phenotype, HAHigh populations retained expression of VDR protein at levels comparable to that of parental Hs578T cells and HALow subclones. Treatment with 1,25D decreased production of HA in both HAHigh and HALow populations. We also found that multiple metabolic enzymes were aberrantly expressed in HAHigh cells, especially those involved in glutamine and glucose metabolism. Notably, Glutaminase (GLS), a known oncogene for breast cancer, was strongly upregulated in HAHigh vs. HALow cells and its expression was significantly reduced by 1,25D (100 nM, 24 h). Consistent with this finding, Seahorse extracellular flux analysis indicated that respiration in HAHigh cells was significantly more dependent on exogenous glutamine than HALow cells, however, acute 1,25D exposure did not alter metabolic flux. In contrast to GLS, the glutamate transporter SLC1A7 was significantly reduced in HAHigh cells compared to HALow cells and its expression was enhanced by 1,25D. These findings support the concept that 1,25D can reverse the metabolic gene expression changes associated with HA production in cancer cells with aggressive phenotypes.

White Matter Abnormalities Linked to Interferon, Stress Response, and Energy Metabolism Gene Expression Changes in Older HIV-Positive Patients on Antiretroviral Therapy.

Neurocognitive impairment (NCI) remains a significant cause of morbidity in human immunodeficiency virus (HIV)-positive individuals despite highly active antiretroviral therapy (HAART). White matter abnormalities have emerged as a key component of age-related neurodegeneration, and accumulating evidence suggests they play a role in HIV-associated neurocognitive disorders. Viral persistence in the brain induces chronic inflammation associated with lymphocytic infiltration, microglial proliferation, myelin loss, and cerebrovascular lesions. In this study, gene expression profiling was performed on frontal white matter from 34 older HIV+ individuals on HAART (18 with NCI) and 24 HIV-negative controls. We used the NanoString nCounter platform to evaluate 933 probes targeting inflammation, interferon and stress responses, energy metabolism, and central nervous system-related genes. Viral loads were measured using single-copy assays. Compared to HIV- controls, HIV+ individuals exhibited increased expression of genes related to interferon, MHC-1, and stress responses, myeloid cells, and T cells and decreased expression of genes associated with oligodendrocytes and energy metabolism in white matter. These findings correlated with increased white matter inflammation and myelin pallor, suggesting interferon (IRFs, IFITM1, ISG15, MX1, OAS3) and stress response (ATF4, XBP1, CHOP, CASP1, WARS) gene expression changes are associated with decreased energy metabolism (SREBF1, SREBF2, PARK2, TXNIP) and oligodendrocyte myelin production (MAG, MOG), leading to white matter dysfunction. Machine learning identified a 15-gene signature predictive of HIV status that was validated in an independent cohort. No specific gene expression patterns were associated with NCI. These findings suggest therapies that decrease chronic inflammation while protecting mitochondrial function may help to preserve white matter integrity in older HIV+ individuals.

Early Root Transcriptomic Changes in Wheat Seedlings Colonized by Trichoderma harzianum Under Different Inorganic Nitrogen Supplies.

Wheat is one of the most important crops worldwide. The use of plant growth promoting microorganisms, such as those of the genus Trichoderma, constitutes an alternative to chemical fertilizers, since they are cheaper and are not detrimental to the environment. However, the interaction between Trichoderma and wheat plants has been scarcely studied, at least at a molecular level. In the present work, a microarray approach was used to study the early transcriptomic changes induced in wheat roots by Trichoderma harzianum, applied alone or in combination with different concentrations of calcium nitrate [Ca(NO3)2], which was last used as nitrogen (N) source. Our results show that T. harzianum causes larger transcriptomic changes than Ca(NO3)2 in wheat roots, and such changes are different when plants are challenged with Trichoderma alone or treated with a combination of T. harzianum and Ca(NO3)2. Overall, T. harzianum activates the expression of defense-related genes at early stages of the interaction with the roots, while this fungus reduces the expression of genes related to plant growth and development. Moreover, the current study in wheat roots, subjected to the different T. harzianum and Ca(NO3)2 combinations, reveals that the number of transcriptomic changes was higher when compared against those caused by the different Ca(NO3)2 concentrations than when it was compared against those caused by T. harzianum. N metabolism gene expression changes were in agreement with the levels of nitrate reductase activity measured in plants from Trichoderma plus Ca(NO3)2 conditions. Results were also concordant with plant phenotypes, which showed reduced growth at early interaction stages when inoculated with T. harzianum or with its combination with Ca(NO3)2 at the lowest dosage. These results were in a good agreement with the recognized role of Trichoderma as an inducer of plant defense.

Adolescent Binge Alcohol Exposure Affects Cardiovascular Function

More than five million underage Americans binge drink, which elevates blood alcohol concentration (BAC) to 0.08 g/dL within 2 hours, at least once per month. However, the consequences of binge drinking on the adolescent heart are unknown. To study this, outbred rats were gavaged 3 g/kg EtOH for 3 days, H2O for 2 days, and EtOH for additional 3 days between postnatal day 36-44 (corresponding to adolescence). The BAC was 0.08 ± 0.01 g/dL. Control rats were gavaged H2O for the 8-day protocol. Both groups had normal food intake and ∼30% weight gain during the protocol. Echocardiography showed Control rats experienced a ∼30% increase in LV end-diastolic diameter (LVEDD) due to normal growth during this period of adolescence along with a parallel increase in end-systolic diameter so that ejection fraction remained constant while stroke volume increased. Conversely, Binge rats experienced only half that increase in LVEDD, and a decreased systolic diameter resulting in increased ejection fraction. One explanation is that impaired cardiac growth from binge alcohol exposure is compensated for by increased systolic function to maintain cardiac output. Increased systolic function in the Binge rats suggested increased beta-adrenergic activation, which was supported by an increase in troponin I PKA phosphorylation. Furthermore, doppler revealed a trend towards reduced E/A ratio in the Binge group, and single cell force measurements found significantly increased passive stiffness, indicating an impact on diastolic function as well. Lastly, we performed RNA-seq and identified a pattern of altered genes that suggested a switch in substrate utilization from fatty acid to glucose metabolism in the Binge rats. In summary, we have determined that adolescent binge alcohol exposure results in slowed normal growth, increased systolic function, depressed diastolic function, and changes in metabolic gene expression, revealing a possibly significant cardiac health risk.

An Ultradian Feeding Schedule in Rats Affects Metabolic Gene Expression in Liver, Brown Adipose Tissue and Skeletal Muscle with Only Mild Effects on Circadian Clocks.

Restricted feeding is well known to affect expression profiles of both clock and metabolic genes. However, it is unknown whether these changes in metabolic gene expression result from changes in the molecular clock or in feeding behavior. Here we eliminated the daily rhythm in feeding behavior by providing 6 meals evenly distributed over the light/dark-cycle. Animals on this 6-meals-a-day feeding schedule retained the normal day/night difference in physiological parameters including body temperature and locomotor activity. The daily rhythm in respiratory exchange ratio (RER), however, was significantly phase-shifted through increased utilization of carbohydrates during the light phase and increased lipid oxidation during the dark phase. This 6-meals-a-day feeding schedule did not have a major impact on the clock gene expression rhythms in the master clock, but did have mild effects on peripheral clocks. In contrast, genes involved in glucose and lipid metabolism showed differential expression. In conclusion, eliminating the daily rhythm in feeding behavior in rats does not affect the master clock and only mildly affects peripheral clocks, but disturbs metabolic rhythms in liver, skeletal muscle and brown adipose tissue in a tissue-dependent manner. Thereby, a clear daily rhythm in feeding behavior strongly regulates timing of peripheral metabolism, separately from circadian clocks.

Abstract 4317: EGLN1/c-Myc induced lymphoid-specific helicase inhibits ferroptosis through lipid metabolic gene expression changes

Abstract Ferroptosis has emerged as a new form of non-apoptotic cell death in multiple human diseases. However, the epigenetic mechanisms of ferroptosis remain poorly defined. We demonstrate that Lymphoid-specific helicase (LSH), a DNA methylation modifier, interacts with WDR76 to inhibit ferroptosis by activating lipid metabolism-associated genes, including GLUT1, and ferroptosis related genes SCD1 and FADS2. These effects are dependent on iron and lipid reactive oxygen species. We further show that EGLN1 and c-Myc directly activate LSH expression by inhibiting HIF-1α. Finally, we demonstrate that LSH functions as an oncogene in lung cancer in vitro and in vivo. Therefore, our study elucidates the molecular basis for a c-Myc/EGLN1-mediated induction of LSH expression to inhibit ferroptosis, which can be exploited for the development of therapeutic agents to target ferroptosis in cancer. Note: This abstract was not presented at the meeting. Citation Format: Yongguang Tao, Shuang Liu, Yiqun Jiang. EGLN1/c-Myc induced lymphoid-specific helicase inhibits ferroptosis through lipid metabolic gene expression changes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4317. doi:10.1158/1538-7445.AM2017-4317

EGLN1/c-Myc Induced Lymphoid-Specific Helicase Inhibits Ferroptosis through Lipid Metabolic Gene Expression Changes.

Ferroptosis is a newly discovered form of non-apoptotic cell death in multiple human diseases. However, the epigenetic mechanisms underlying ferroptosis remain poorly defined. First, we demonstrated that lymphoid-specific helicase (LSH), which is a DNA methylation modifier, interacted with WDR76 to inhibit ferroptosis by activating lipid metabolism-associated genes, including GLUT1, and ferroptosis related genes SCD1 and FADS2, in turn, involved in the Warburg effect. WDR76 targeted these genes expression in dependent manner of LSH and chromatin modification in DNA methylation and histone modification. These effects were dependent on iron and lipid reactive oxygen species. We further demonstrated that EGLN1 and c-Myc directly activated the expression of LSH by inhibiting HIF-1α. Finally, we demonstrated that LSH functioned as an oncogene in lung cancer in vitro and in vivo. Therefore, our study elucidates the molecular basis of the c-Myc/EGLN1-mediated induction of LSH expression that inhibits ferroptosis, which can be exploited for the development of therapeutic strategies targeting ferroptosis for the treatment of cancer.

Bile acid receptor agonists INT747 and INT777 decrease oestrogen deficiency-related postmenopausal obesity and hepatic steatosis in mice

Menopause is often followed by obesity and, related to this, non-alcoholic fatty liver disease (NAFLD). Two bile acid (BA) receptors, farnesoid X receptor (FXR) and G-protein-coupled receptor TGR5, have emerged as putative therapeutic targets for obesity and NAFLD.Aim of this study: to evaluate the efficacy of selective agonists INT747/obeticholic acid (FXR) and INT777 (TGR5) as novel treatments for the metabolic effects of oestrogen deficiency.Ovariectomized (OVX) or sham-operated (SHAM) mice were fed a high-fat diet (HFD) for 5weeks. During the last 4weeks two groups of OVX and SHAM mice received either INT747- or INT777-supplemented HFD.OVX mice had significantly higher bodyweight gain than SHAM mice, which was attenuated by INT747- or INT777-treatment. No significant changes in food intake or physical activity were found. OVX mice had significantly lower energy expenditure than SHAM mice; INT747- and INT777-treated OVX mice had intermediate energy expenditure. Liver triglyceride and cholesterol content was significantly increased in OVX compared to SHAM mice, which was normalized by INT747- or INT777-treatment. Significant changes in metabolic gene expression were found in liver (Cpt1, Acox1), muscle (Ucp3, Pdk4, Cpt1, Acox1, Fasn, Fgf21), brown adipocytes (Dio2) and white adipocytes (c/EBPα, Pparγ, Adipoq). For the first time, expression of FXR and induction of its target gene Pltp1 was shown in skeletal muscle.BA receptor agonists are suitable therapeutics to correct postmenopausal metabolic changes in an OVX mouse model. Potential mechanisms include increased energy expenditure and changes in expression patterns of key metabolic genes in liver, muscle and adipose tissues.

Gene expression signatures of breast cancer stem and progenitor cells do not exhibit features of Warburg metabolism.

IntroductionCancers are believed to adapt to continual changes in glucose and oxygen availability by relying almost exclusively on glycolytic metabolism for energy (i.e. the Warburg effect). The process by which breast cancers sustain growth in avascular tissue is thought to be mediated via aberrant hypoxia response with ensuing shifts in glycolytic metabolism. Given their role in initiating and perpetuating tumors, we sought to determine whether breast cancer stem and progenitor cells play an instrumental role in this adaptive metabolic response.MethodsBreast cancer stem/progenitor cells were isolated from invasive ductal carcinomas, and benign stem cells (SC) were isolated from reduction mammoplasty tissues. Relative expression of 33 genes involved in hypoxia and glucose metabolism was evaluated in flow cytometrically isolated stem and progenitor cell populations. Significance between cohorts and cell populations was determined using Student’s 2-tailed t test.ResultsWhile benign stem/progenitor cells exhibited few significant inter-group differences in expression of genes involved in hypoxia regulation or glucose metabolism, breast cancer stem/progenitor cells demonstrated significant inter-group variability. Breast cancer stem/progenitor cells adapted to microenvironments through changes in stem cell numbers and transcription of glycolytic genes. One of four breast cancer stem/progenitor cells subpopulations exhibited an aerobic glycolysis gene expression signature. This subpopulation comprises the majority of the tumor and therefore best reflects invasive ductal carcinoma tumor biology. Although PI3K/AKT mutations are associated with increased proliferation of breast cancer cells, mutations in breast cancer stem/progenitor cells subpopulations did not correlate with changes in metabolic gene expression.ConclusionsThe adaptive capacity of breast cancer stem/progenitor cells may enable tumors to survive variable conditions encountered during progressive stages of cancer growth.