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1.
Cancer Res ; 2024 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-38657108

RESUMEN

Solid tumors are highly reliant on lipids for energy, growth, and survival. In prostate cancer, the activity of the androgen receptor (AR) is associated with reprogramming of lipid metabolic processes. Here, we identified acyl-CoA synthetase medium chain family members 1 and 3 (ACSM1 and ACSM3) as AR-regulated mediators of prostate cancer metabolism and growth. ACSM1 and ACSM3 were upregulated in prostate tumors compared to non-malignant tissues and other cancer types. Both enzymes enhanced proliferation and protected prostate cancer cells from death in vitro, while silencing ACSM3 led to reduced tumor growth in an orthotopic xenograft model. ACSM1 and ACSM3 were major regulators of the prostate cancer lipidome and enhanced energy production via fatty acid oxidation. Metabolic dysregulation caused by loss of ACSM1/3 led to mitochondrial oxidative stress, lipid peroxidation and cell death by ferroptosis. Conversely, elevated ACSM1/3 activity enabled prostate cancer cells to survive toxic levels of medium chain fatty acids and promoted resistance to ferroptosis-inducing drugs and AR antagonists. Collectively, this study reveals a tumor-promoting function for medium chain acyl-CoA synthetases and positions ACSM1 and ACSM3 as key players in prostate cancer progression and therapy resistance.

2.
Adv Sci (Weinh) ; : e2307963, 2024 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-38602451

RESUMEN

In recent decades, the role of tumor biomechanics on cancer cell behavior at the primary site has been increasingly appreciated. However, the effect of primary tumor biomechanics on the latter stages of the metastatic cascade, such as metastatic seeding of secondary sites and outgrowth remains underappreciated. This work sought to address this in the context of triple negative breast cancer (TNBC), a cancer type known to aggressively disseminate at all stages of disease progression. Using mechanically tuneable model systems, mimicking the range of stiffness's typically found within breast tumors, it is found that, contrary to expectations, cancer cells exposed to softer microenvironments are more able to colonize secondary tissues. It is shown that heightened cell survival is driven by enhanced metabolism of fatty acids within TNBC cells exposed to softer microenvironments. It is demonstrated that uncoupling cellular mechanosensing through integrin ß1 blocking antibody effectively causes stiff primed TNBC cells to behave like their soft counterparts, both in vitro and in vivo. This work is the first to show that softer tumor microenvironments may be contributing to changes in disease outcome by imprinting on TNBC cells a greater metabolic flexibility and conferring discrete cell survival advantages.

3.
Br J Cancer ; 130(5): 741-754, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38216720

RESUMEN

BACKGROUND: Peroxisomes are central metabolic organelles that have key roles in fatty acid homoeostasis. As prostate cancer (PCa) is particularly reliant on fatty acid metabolism, we explored the contribution of peroxisomal ß-oxidation (perFAO) to PCa viability and therapy response. METHODS: Bioinformatic analysis was performed on clinical transcriptomic datasets to identify the perFAO enzyme, 2,4-dienoyl CoA reductase 2 (DECR2) as a target gene of interest. Impact of DECR2 and perFAO inhibition via thioridazine was examined in vitro, in vivo, and in clinical prostate tumours cultured ex vivo. Transcriptomic and lipidomic profiling was used to determine the functional consequences of DECR2 inhibition in PCa. RESULTS: DECR2 is upregulated in clinical PCa, most notably in metastatic castrate-resistant PCa (CRPC). Depletion of DECR2 significantly suppressed proliferation, migration, and 3D growth of a range of CRPC and therapy-resistant PCa cell lines, and inhibited LNCaP tumour growth and proliferation in vivo. DECR2 influences cell cycle progression and lipid metabolism to support tumour cell proliferation. Further, co-targeting of perFAO and standard-of-care androgen receptor inhibition enhanced suppression of PCa cell proliferation. CONCLUSION: Our findings support a focus on perFAO, specifically DECR2, as a promising therapeutic target for CRPC and as a novel strategy to overcome lethal treatment resistance.


Asunto(s)
Neoplasias de la Próstata Resistentes a la Castración , Masculino , Humanos , Neoplasias de la Próstata Resistentes a la Castración/tratamiento farmacológico , Neoplasias de la Próstata Resistentes a la Castración/genética , Neoplasias de la Próstata Resistentes a la Castración/metabolismo , Metabolismo de los Lípidos/genética , Línea Celular Tumoral , Receptores Androgénicos/genética , Receptores Androgénicos/metabolismo , Andrógenos/metabolismo , Proliferación Celular , Ácidos Grasos
4.
Biochem Biophys Res Commun ; 691: 149273, 2024 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-38029544

RESUMEN

Recently, the fatty acid elongation enzyme ELOVL5 was identified as a critical pro-metastatic factor in prostate cancer, required for cell growth and mitochondrial homeostasis. The fatty acid elongation reaction catalyzed by ELOVL5 utilizes malonyl-CoA as the carbon donor. Here, we demonstrate that ELOVL5 knockdown causes malonyl-CoA accumulation. Malonyl-CoA is a cellular substrate that can inhibit fatty acid ß-oxidation in the mitochondria through allosteric inhibition of carnitine palmitoyltransferase 1A (CPT1A), the enzyme that controls the rate-limiting step of the long chain fatty acid ß-oxidation cycle. We hypothesized that changes in malonyl-CoA abundance following ELOVL5 knockdown could influence mitochondrial ß-oxidation rates in prostate cancer cells, and regulate cell viability. Accordingly, we find that ELOVL5 knockdown is associated with decreased mitochondrial ß-oxidation in prostate cancer cells. Combining ELOVL5 knockdown with FASN inhibition to increase malonyl-CoA abundance endogenously enhances the effect of ELOVL5 knockdown on prostate cancer cell viability, while preventing malonyl-CoA production rescues the cells from the effect of ELOVL5 knockdown. Our findings indicate an additional role for fatty acid elongation, in the control of malonyl-CoA homeostasis, alongside its established role in the production of long-chain fatty acid species, to explain the importance of fatty acid elongation for cell viability.


Asunto(s)
Malonil Coenzima A , Neoplasias de la Próstata , Masculino , Humanos , Malonil Coenzima A/metabolismo , Malonil Coenzima A/farmacología , Supervivencia Celular , Ácidos Grasos/metabolismo , Mitocondrias/metabolismo , Oxidación-Reducción , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/metabolismo , Carnitina O-Palmitoiltransferasa/metabolismo
5.
FEBS Lett ; 597(17): 2196-2220, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37463842

RESUMEN

The nicotinamide adenine dinucleotide (NAD+ ) precursor nicotinamide mononucleotide (NMN) is a proposed therapy for age-related disease, whereby it is assumed that NMN is incorporated into NAD+ through the canonical recycling pathway. During oral delivery, NMN is exposed to the gut microbiome, which could modify the NAD+ metabolome through enzyme activities not present in the mammalian host. We show that orally delivered NMN can undergo deamidation and incorporation in mammalian tissue via the de novo pathway, which is reduced in animals treated with antibiotics to ablate the gut microbiome. Antibiotics increased the availability of NAD+ metabolites, suggesting the microbiome could be in competition with the host for dietary NAD+ precursors. These findings highlight new interactions between NMN and the gut microbiome.


Asunto(s)
Microbiota , Mononucleótido de Nicotinamida , Animales , Mononucleótido de Nicotinamida/metabolismo , NAD/metabolismo , Antibacterianos , Mamíferos/metabolismo
6.
Physiol Rep ; 11(1): e15549, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36597221

RESUMEN

Efficacy of therapies that target the downstream nitric oxide (NO) pathway in pulmonary arterial hypertension (PAH) depends on the bioavailability of NO. Reduced NO level in PAH is secondary to "uncoupling" of endothelial nitric oxide synthase (eNOS). Stimulation of ß3 adrenergic receptors (ß3 ARs) may lead to the recoupling of NOS and therefore be beneficial in PAH. We aimed to examine the efficacy of ß3 AR agonism as a novel pathway in experimental PAH. In hypoxia (5 weeks) and Sugen hypoxia (hypoxia for 5 weeks + SU5416 injection) models of PAH, we examined the effects of the selective ß3 AR agonist CL316243. We measured echocardiographic indices and invasive right ventricular (RV)-pulmonary arterial (PA) hemodynamics and compared CL316243 with riociguat and sildenafil. We assessed treatment effects on RV-PA remodeling, oxidative stress, and eNOS glutathionylation, an oxidative modification that uncouples eNOS. Compared with normoxic mice, RV systolic pressure was increased in the control hypoxic mice (p < 0.0001) and Sugen hypoxic mice (p < 0.0001). CL316243 reduced RV systolic pressure, to a similar degree to riociguat and sildenafil, in both hypoxia (p < 0.0001) and Sugen hypoxia models (p < 0.03). CL316243 reversed pulmonary vascular remodeling, decreased RV afterload, improved RV-PA coupling efficiency and reduced RV stiffness, hypertrophy, and fibrosis. Although all treatments decreased oxidative stress, CL316243 significantly reduced eNOS glutathionylation. ß3 AR stimulation improved RV hemodynamics and led to beneficial RV-PA remodeling in experimental models of PAH. ß3 AR agonists may be effective therapies in PAH.


Asunto(s)
Hipertensión Pulmonar , Hipertensión Arterial Pulmonar , Ratones , Animales , Hipertensión Arterial Pulmonar/tratamiento farmacológico , Hipertensión Arterial Pulmonar/metabolismo , Hipertensión Pulmonar/metabolismo , Citrato de Sildenafil/farmacología , Citrato de Sildenafil/uso terapéutico , Arteria Pulmonar/metabolismo , Hemodinámica , Agonistas Adrenérgicos beta/farmacología , Hipoxia
7.
Elife ; 112022 11 17.
Artículo en Inglés | MEDLINE | ID: mdl-36394259

RESUMEN

Obesity is generally associated with insulin resistance in liver and muscle and increased risk of developing type 2 diabetes, however there is a population of obese people that remain insulin sensitive. Similarly, recent work suggests that mice fed high carbohydrate diets can become obese without apparent glucose intolerance. To investigate this phenomenon further, we fed mice either a high fat (Hi-F) or high starch (Hi-ST) diet and measured adiposity, glucose tolerance, insulin sensitivity, and tissue lipids compared to control mice fed a standard laboratory chow. Both Hi-ST and Hi-F mice accumulated a similar amount of fat and tissue triglyceride compared to chow-fed mice. However, while Hi-F diet mice developed glucose intolerance as well as liver and muscle insulin resistance (assessed via euglycaemic/hyperinsulinaemic clamp), obese Hi-ST mice maintained glucose tolerance and insulin action similar to lean, chow-fed controls. This preservation of insulin action despite obesity in Hi-ST mice was associated with differences in de novo lipogenesis and levels of C22:0 ceramide in liver and C18:0 ceramide in muscle. This indicates that dietary manipulation can influence insulin action independently of the level of adiposity and that the presence of specific ceramide species correlates with these differences.


Asunto(s)
Diabetes Mellitus Tipo 2 , Intolerancia a la Glucosa , Resistencia a la Insulina , Ratones , Animales , Almidón , Obesidad , Dieta Alta en Grasa/efectos adversos , Insulina , Ratones Obesos , Ceramidas , Glucosa
8.
Oncogene ; 41(34): 4066-4078, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35851845

RESUMEN

Glutamine is a conditionally essential nutrient for many cancer cells, but it remains unclear how consuming glutamine in excess of growth requirements confers greater fitness to glutamine-addicted cancers. By contrasting two breast cancer subtypes with distinct glutamine dependencies, we show that glutamine-indispensable triple-negative breast cancer (TNBC) cells rely on a non-canonical glutamine-to-glutamate overflow, with glutamine carbon routed once through the TCA cycle. Importantly, this single-pass glutaminolysis increases TCA cycle fluxes and replenishes TCA cycle intermediates in TNBC cells, a process that achieves net oxidation of glucose but not glutamine. The coupling of glucose and glutamine catabolism appears hard-wired via a distinct TNBC gene expression profile biased to strip and then sequester glutamine nitrogen, but hampers the ability of TNBC cells to oxidise glucose when glutamine is limiting. Our results provide a new understanding of how metabolically rigid TNBC cells are sensitive to glutamine deprivation and a way to select vulnerable TNBC subtypes that may be responsive to metabolic-targeted therapies.


Asunto(s)
Glutamina , Neoplasias de la Mama Triple Negativas , Línea Celular Tumoral , Ciclo del Ácido Cítrico , Glucosa/metabolismo , Ácido Glutámico/metabolismo , Glutamina/metabolismo , Humanos , Neoplasias de la Mama Triple Negativas/genética , Neoplasias de la Mama Triple Negativas/metabolismo
9.
PLoS Comput Biol ; 18(6): e1010203, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35759507

RESUMEN

The topology of metabolic networks is recognisably modular with modules weakly connected apart from sharing a pool of currency metabolites. Here, we defined modules as sets of reversible reactions isolated from the rest of metabolism by irreversible reactions except for the exchange of currency metabolites. Our approach identifies topologically independent modules under specific conditions associated with different metabolic functions. As case studies, the E.coli iJO1366 and Human Recon 2.2 genome-scale metabolic models were split in 103 and 321 modules respectively, displaying significant correlation patterns in expression data. Finally, we addressed a fundamental question about the metabolic flexibility conferred by reversible reactions: "Of all Directed Topologies (DTs) defined by fixing directions to all reversible reactions, how many are capable of carrying flux through all reactions?". Enumeration of the DTs for iJO1366 model was performed using an efficient depth-first search algorithm, rejecting infeasible DTs based on mass-imbalanced and loopy flux patterns. We found the direction of 79% of reversible reactions must be defined before all directions in the network can be fixed, granting a high degree of flexibility.


Asunto(s)
Redes y Vías Metabólicas , Modelos Biológicos , Algoritmos , Escherichia coli/genética , Escherichia coli/metabolismo , Genoma , Humanos , Redes y Vías Metabólicas/genética
10.
Elife ; 102021 08 12.
Artículo en Inglés | MEDLINE | ID: mdl-34382934

RESUMEN

Alterations to the androgen receptor (AR) signalling axis and cellular metabolism are hallmarks of prostate cancer. This study provides insight into both hallmarks by uncovering a novel link between AR and the pentose phosphate pathway (PPP). Specifically, we identify 6-phosphogluoconate dehydrogenase (6PGD) as an androgen-regulated gene that is upregulated in prostate cancer. AR increased the expression of 6PGD indirectly via activation of sterol regulatory element binding protein 1 (SREBP1). Accordingly, loss of 6PGD, AR or SREBP1 resulted in suppression of PPP activity as revealed by 1,2-13C2 glucose metabolic flux analysis. Knockdown of 6PGD also impaired growth and elicited death of prostate cancer cells, at least in part due to increased oxidative stress. We investigated the therapeutic potential of targeting 6PGD using two specific inhibitors, physcion and S3, and observed substantial anti-cancer activity in multiple models of prostate cancer, including aggressive, therapy-resistant models of castration-resistant disease as well as prospectively collected patient-derived tumour explants. Targeting of 6PGD was associated with two important tumour-suppressive mechanisms: first, increased activity of the AMP-activated protein kinase (AMPK), which repressed anabolic growth-promoting pathways regulated by acetyl-CoA carboxylase 1 (ACC1) and mammalian target of rapamycin complex 1 (mTORC1); and second, enhanced AR ubiquitylation, associated with a reduction in AR protein levels and activity. Supporting the biological relevance of positive feedback between AR and 6PGD, pharmacological co-targeting of both factors was more effective in suppressing the growth of prostate cancer cells than single-agent therapies. Collectively, this work provides new insight into the dysregulated metabolism of prostate cancer and provides impetus for further investigation of co-targeting AR and the PPP as a novel therapeutic strategy.


Asunto(s)
Gliceraldehído-3-Fosfato Deshidrogenasas/metabolismo , Neoplasias de la Próstata/metabolismo , Receptores Androgénicos/metabolismo , Proteínas Quinasas Activadas por AMP/metabolismo , Acetil-CoA Carboxilasa/metabolismo , Línea Celular , Emodina/análogos & derivados , Retroalimentación , Regulación Neoplásica de la Expresión Génica , Técnicas de Silenciamiento del Gen , Humanos , Masculino , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Vía de Pentosa Fosfato , Neoplasias de la Próstata/genética , Transducción de Señal , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/metabolismo
11.
Am J Physiol Endocrinol Metab ; 321(1): E176-E189, 2021 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-34121447

RESUMEN

Almost 40% of adults worldwide are classified as overweight or obese. Exercise is a beneficial intervention in obesity, partly due to increases in mitochondrial activity and subsequent increases in nicotinamide adenine dinucleotide (NAD+), an important metabolic cofactor. Recent studies have shown that increasing NAD+ levels through pharmacological supplementation with precursors such as nicotinamide mononucleotide (NMN) improved metabolic health in high-fat-diet (HFD)-fed mice. However, the effects of combined exercise and NMN supplementation are unknown. Thus, here we examined the combined effects of NMN and treadmill exercise in female mice with established obesity after 10 wk of diet. Five-week-old female C57BL/6J mice were exposed to a control diet (n = 16) or HFD. Mice fed a HFD were either untreated (HFD; n = 16), received NMN in drinking water (400 mg/kg; HNMN; n = 16), were exposed to treadmill exercise 6 days/wk (HEx; n = 16), or were exposed to exercise combined with NMN (HNEx; n = 16). Although some metabolic benefits of NMN have been described, at this dose, NMN administration impaired several aspects of exercise-induced benefits in obese mice, including glucose tolerance, glucose-stimulated insulin secretion from islets, and hepatic triglyceride accumulation. HNEx mice also exhibited increased antioxidant and reduced prooxidant gene expression in both islets and muscle, suggesting that altered redox status is associated with the loss of exercise-induced health benefits with NMN cotreatment. Our data show that NMN treatment impedes the beneficial metabolic effects of exercise in a mouse model of diet-induced obesity in association with disturbances in redox metabolism.NEW & NOTEWORTHY NMN dampened exercise-induced benefits on glucose handling in diet-induced obesity. NMN administration alongside treadmill exercise enhanced the ratio of antioxidants to prooxidants. We suggest that NMN administration may not be beneficial when NAD+ levels are replete.


Asunto(s)
Glucosa/metabolismo , Mononucleótido de Nicotinamida/administración & dosificación , Obesidad/metabolismo , Condicionamiento Físico Animal/fisiología , Animales , Dieta Alta en Grasa , Suplementos Dietéticos , Femenino , Glucosa/farmacología , Intolerancia a la Glucosa/terapia , Secreción de Insulina/efectos de los fármacos , Hígado/efectos de los fármacos , Hígado/metabolismo , Ratones , Ratones Endogámicos C57BL , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , NAD/metabolismo , Mononucleótido de Nicotinamida/efectos adversos , Obesidad/etiología , Obesidad/terapia , Triglicéridos/metabolismo
12.
J Physiol ; 599(5): 1513-1531, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33492681

RESUMEN

KEY POINTS: Acute nicotinamide riboside (NR) supplementation does not alter substrate metabolism at rest, during or in recovery from endurance exercise. NR does not alter NAD+ -sensitive signalling pathways in human skeletal muscle. NR supplementation and acute exercise influence the NAD+ metabolome. ABSTRACT: Oral supplementation of the NAD+ precursor nicotinamide riboside (NR) has been reported to alter metabolism alongside increasing sirtuin (SIRT) signalling and mitochondrial biogenesis in rodent skeletal muscle. However, whether NR supplementation can elicit a similar response in human skeletal muscle is unclear. This study assessed the effect of 7-day NR supplementation on whole-body metabolism and exercise-induced mitochondrial biogenic signalling in skeletal muscle. Eight male participants (age: 23 ± 4 years, V̇O2peak 46.5 ± 4.4 ml kg-1  min-1 ) received 1 week of NR or cellulose placebo (PLA) supplementation (1000 mg day-1 ). Muscle biopsies were collected from the medial vastus lateralis prior to supplementation and pre-, immediately post- and 3 h post-exercise (1 h of 60% Wmax cycling) performed following the supplementation period. There was no effect of NR supplementation on substrate utilisation at rest or during exercise or on skeletal muscle mitochondrial respiration. Global acetylation, auto-PARylation of poly ADP-ribose polymerase 1 (PARP1), acetylation of Tumour protein 53 (p53)Lys382 and Manganese superoxide dismutase (MnSOD)Lys122 were also unaffected by NR supplementation or exercise. NR supplementation did not increase skeletal muscle NAD+ concentration, but it did increase the concentration of deaminated NAD+ precursors nicotinic acid riboside (NAR) and nicotinic acid mononucleotide (NAM) and methylated nicotinamide breakdown products (Me2PY and Me4PY), demonstrating the skeletal muscle bioavailability of NR supplementation. In summary, 1 week of NR supplementation does not alter whole-body metabolism or skeletal muscle signal transduction pathways implicated in the mitochondrial adaptation to endurance exercise.


Asunto(s)
Músculo Esquelético , Niacinamida , Suplementos Dietéticos , Ejercicio Físico , Masculino , NAD , Niacinamida/análogos & derivados , Compuestos de Piridinio
14.
iScience ; 23(9): 101479, 2020 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-32891058

RESUMEN

Insulin regulates glucose metabolism through thousands of regulatory mechanisms; however, which regulatory mechanisms are keys to control glucose metabolism remains unknown. Here, we performed kinetic trans-omic analysis by integrating isotope-tracing glucose flux and phosphoproteomic data from insulin-stimulated adipocytes and built a kinetic mathematical model to identify key allosteric regulatory and phosphorylation events for enzymes. We identified nine reactions regulated by allosteric effectors and one by enzyme phosphorylation and determined the regulatory mechanisms for three of these reactions. Insulin stimulated glycolysis by promoting Glut4 activity by enhancing phosphorylation of AS160 at S595, stimulated fatty acid synthesis by promoting Acly activity through allosteric activation by glucose 6-phosphate or fructose 6-phosphate, and stimulated glutamate synthesis by alleviating allosteric inhibition of Gls by glutamate. Most of glycolytic reactions were regulated by amounts of substrates and products. Thus, phosphorylation or allosteric modulator-based regulation of only a few key enzymes was sufficient to change insulin-induced metabolism.

15.
J Biol Chem ; 295(38): 13250-13266, 2020 09 18.
Artículo en Inglés | MEDLINE | ID: mdl-32723868

RESUMEN

Adipose tissue is essential for metabolic homeostasis, balancing lipid storage and mobilization based on nutritional status. This is coordinated by insulin, which triggers kinase signaling cascades to modulate numerous metabolic proteins, leading to increased glucose uptake and anabolic processes like lipogenesis. Given recent evidence that glucose is dispensable for adipocyte respiration, we sought to test whether glucose is necessary for insulin-stimulated anabolism. Examining lipogenesis in cultured adipocytes, glucose was essential for insulin to stimulate the synthesis of fatty acids and glyceride-glycerol. Importantly, glucose was dispensable for lipogenesis in the absence of insulin, suggesting that distinct carbon sources are used with or without insulin. Metabolic tracing studies revealed that glucose was required for insulin to stimulate pathways providing carbon substrate, NADPH, and glycerol 3-phosphate for lipid synthesis and storage. Glucose also displaced leucine as a lipogenic substrate and was necessary to suppress fatty acid oxidation. Together, glucose provided substrates and metabolic control for insulin to promote lipogenesis in adipocytes. This contrasted with the suppression of lipolysis by insulin signaling, which occurred independently of glucose. Given previous observations that signal transduction acts primarily before glucose uptake in adipocytes, these data are consistent with a model whereby insulin initially utilizes protein phosphorylation to stimulate lipid anabolism, which is sustained by subsequent glucose metabolism. Consequently, lipid abundance was sensitive to glucose availability, both during adipogenesis and in Drosophila flies in vivo Together, these data highlight the importance of glucose metabolism to support insulin action, providing a complementary regulatory mechanism to signal transduction to stimulate adipose anabolism.


Asunto(s)
Adipocitos/metabolismo , Proteínas de Drosophila/metabolismo , Glucosa/metabolismo , Insulina/metabolismo , Lipogénesis , Transducción de Señal , Células 3T3-L1 , Animales , Drosophila melanogaster , Glicerofosfatos/metabolismo , Ratones , NADP/metabolismo
16.
iScience ; 23(2): 100855, 2020 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-32058966

RESUMEN

Cellular metabolism is dynamic, but quantifying non-steady metabolic fluxes by stable isotope tracers presents unique computational challenges. Here, we developed an efficient 13C-tracer dynamic metabolic flux analysis (13C-DMFA) framework for modeling central carbon fluxes that vary over time. We used B-splines to generalize the flux parameterization system and to improve the stability of the optimization algorithm. As proof of concept, we investigated how 3T3-L1 cultured adipocytes acutely metabolize glucose in response to insulin. Insulin rapidly stimulates glucose uptake, but intracellular pathways responded with differing speeds and magnitudes. Fluxes in lower glycolysis increased faster than those in upper glycolysis. Glycolysis fluxes rose disproportionally larger and faster than the tricarboxylic acid cycle, with lactate a primary glucose end product. The uncovered array of flux dynamics suggests that glucose catabolism is additionally regulated beyond uptake to help shunt glucose into appropriate pathways. This work demonstrates the value of using dynamic intracellular fluxes to understand metabolic function and pathway regulation.

17.
J Biol Chem ; 295(1): 83-98, 2020 01 03.
Artículo en Inglés | MEDLINE | ID: mdl-31690627

RESUMEN

Adipose tissue is essential for whole-body glucose homeostasis, with a primary role in lipid storage. It has been previously observed that lactate production is also an important metabolic feature of adipocytes, but its relationship to adipose and whole-body glucose disposal remains unclear. Therefore, using a combination of metabolic labeling techniques, here we closely examined lactate production of cultured and primary mammalian adipocytes. Insulin treatment increased glucose uptake and conversion to lactate, with the latter responding more to insulin than did other metabolic fates of glucose. However, lactate production did not just serve as a mechanism to dispose of excess glucose, because we also observed that lactate production in adipocytes did not solely depend on glucose availability and even occurred independently of glucose metabolism. This suggests that lactate production is prioritized in adipocytes. Furthermore, knocking down lactate dehydrogenase specifically in the fat body of Drosophila flies lowered circulating lactate and improved whole-body glucose disposal. These results emphasize that lactate production is an additional metabolic role of adipose tissue beyond lipid storage and release.


Asunto(s)
Adipocitos/metabolismo , Homeostasis , Ácido Láctico/biosíntesis , Células 3T3 , Animales , Células Cultivadas , Drosophila , Cuerpo Adiposo/metabolismo , Glucosa/metabolismo , Insulina/metabolismo , Ácido Láctico/metabolismo , Masculino , Ratones , Ratas , Ratas Sprague-Dawley
18.
Redox Biol ; 28: 101374, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31743887

RESUMEN

A hallmark of cancer cells is their ability to reprogram nutrient metabolism. Thus, disruption to this phenotype is a potential avenue for anti-cancer therapy. Herein we used a phenotypic chemical library screening approach to identify molecules that disrupted nutrient metabolism (by increasing cellular oxygen consumption rate) and were toxic to cancer cells. From this screen we discovered a 1,4-Naphthoquinone (referred to as BH10) that is toxic to a broad range of cancer cell types. BH10 has improved cancer-selective toxicity compared to doxorubicin, 17-AAG, vitamin K3, and other known anti-cancer quinones. BH10 increases glucose oxidation via both mitochondrial and pentose phosphate pathways, decreases glycolysis, lowers GSH:GSSG and NAPDH/NAPD+ ratios exclusively in cancer cells, and induces necrosis. BH10 targets mitochondrial redox defence as evidenced by increased mitochondrial peroxiredoxin 3 oxidation and decreased mitochondrial aconitase activity, without changes in markers of cytosolic or nuclear damage. Over-expression of mitochondria-targeted catalase protects cells from BH10-mediated toxicity, while the thioredoxin reductase inhibitor auranofin synergistically enhances BH10-induced peroxiredoxin 3 oxidation and cytotoxicity. Overall, BH10 represents a 1,4-Naphthoquinone with an improved cancer-selective cytotoxicity profile via its mitochondrial specificity.


Asunto(s)
Mitocondrias/metabolismo , Naftoquinonas/farmacología , Estrés Oxidativo/efectos de los fármacos , Consumo de Oxígeno/efectos de los fármacos , Benzoquinonas/farmacología , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Doxorrubicina/farmacología , Glucólisis/efectos de los fármacos , Humanos , Lactamas Macrocíclicas/farmacología , Mitocondrias/efectos de los fármacos , Fenotipo , Bibliotecas de Moléculas Pequeñas/farmacología , Vitamina K 3/farmacología
19.
Mol Genet Metab ; 128(4): 476-482, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31679996

RESUMEN

A small minority (< 3%) of protein-coding genetic variants are predicted to lead to loss of protein function. However, these predicted loss-of-function (pLOF) variants can provide insight into mode of transcriptional effect. To examine how these changes are propagated to phenotype, we determined associations with downstream metabolites. We performed association analyses of 37 pLOF variants - previously reported to be significantly associated with disease in >400,000 subjects in UK Biobank - with metabolites. We conducted these analyses in three community-based cohorts: the Framingham Heart Study (FHS) Offspring Cohort, FHS Generation 3, and the KORA F4 cohort. We identified 19 new low-frequency or rare (minor allele frequency (MAF) <5%) pLOF variant-metabolite associations, and 12 new common (MAF > 5%) pLOF variant-metabolite associations. Rare pLOF variants in the genes BTN3A2, ENPEP, and GEM that have been associated with blood pressure in UK Biobank, were associated with vasoactive metabolites indoxyl sulfate, asymmetric dimethylarginine (ADMA), and with niacinamide, respectively. A common pLOF variant in gene CCHCR1, associated with asthma in UK Biobank, was associated with histamine and niacinamide in FHS Generation 3, both reported to play a role in this disease. Common variants in olfactory receptor gene OX4C11 that associated with blood pressure in UK Biobank were associated with the nicotine metabolite cotinine, suggesting an interaction between altered olfaction, smoking behaviour, and blood pressure. These findings provide biological validity for pLOF variant-disease associations, and point to the effector roles of common metabolites. Such an approach may provide novel disease markers and therapeutic targets.


Asunto(s)
Metabolismo Energético , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Mutación con Pérdida de Función , Fenotipo , Alelos , Biomarcadores , Presión Sanguínea , Frecuencia de los Genes , Estudios de Asociación Genética/métodos , Histamina/metabolismo , Humanos
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