RESUMEN
Glycine-12 mutations in the GTPase KRAS (KRASG12) are an initiating event for development of lung adenocarcinoma (LUAD). KRASG12 mutations promote cell-intrinsic rewiring of alveolar type-II progenitor (AT2) cells, but to what extent such changes interplay with lung homeostasis and cell fate pathways is unclear. Here, we generated single-cell RNA-seq (scRNA-seq) profiles from AT2-mesenchyme organoid co-cultures, mice, and stage-IA LUAD patients, identifying conserved regulators of AT2 transcriptional dynamics and defining the impact of KRASG12D mutation with temporal resolution. In AT2WT organoids, we found a transient injury/plasticity state preceding AT2 self-renewal and AT1 differentiation. Early-stage AT2KRAS cells exhibited perturbed gene expression dynamics, most notably retention of the injury/plasticity state. The injury state in AT2KRAS cells of patients, mice, and organoids was distinguishable from AT2WT states via altered receptor expression, including co-expression of ITGA3 and SRC. The combination of clinically relevant KRASG12D and SRC inhibitors impaired AT2KRAS organoid growth. Together, our data show that an injury/plasticity state essential for lung repair is co-opted during AT2 self-renewal and LUAD initiation, suggesting that early-stage LUAD may be susceptible to interventions that target specifically the oncogenic nature of this cell state.
Asunto(s)
Neoplasias Pulmonares , Organoides , Proteínas Proto-Oncogénicas p21(ras) , Animales , Humanos , Ratones , Adenocarcinoma del Pulmón/genética , Adenocarcinoma del Pulmón/patología , Adenocarcinoma del Pulmón/metabolismo , Diferenciación Celular , Regulación Neoplásica de la Expresión Génica , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/metabolismo , Mutación , Organoides/metabolismo , Organoides/patología , Proteínas Proto-Oncogénicas p21(ras)/genética , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Familia-src Quinasas/metabolismo , Familia-src Quinasas/genéticaRESUMEN
Altered lipid metabolism is a common hallmark of various cancers, including intrahepatic cholangiocarcinoma (ICC), a highly lethal carcinoma that lacks effective treatment options. To elucidate the lipid metabolism changes in ICC, we coupled the expression of the firefly luciferase gene (FFL) to AKT1 (AKT-FFL) via an IRES linker, and then hydrodynamically injected mice with AKT-FFL and Notch1 intracellular cytoplasmic domain (NICD) to establish a luciferase-positive ICC model. This model not only enabled us to monitor and quantify tumor growth by injecting the mice with luciferin, but also allowed us to assess the fatty acid uptake rate by injecting the mice with free fatty acid luciferin (FFA-Luc). The ICC model exhibited robust uptake of exogenous fatty acids compared with the HCC model induced by AKT-FFL/ neuroblastoma Ras (Ras). Lipidomics analysis showed a dramatically higher level of fatty acid in ICC, further supporting the increased fatty acids uptake. Mechanistic studies identified FATP5 as the predominant mediator of fatty acid uptake required for ICC growth using Fatp5 knockout mice and AAV-based shRNA silencing of Fatp5. Our study discovered a novel therapeutic target for the treatment of ICC and shed light on the contributions of lipid metabolism to ICC development. IMPLICATIONS: This study provides the first in vivo evidence that FATP5 is a potential therapeutic target for treating ICC.
Asunto(s)
Neoplasias de los Conductos Biliares , Colangiocarcinoma , Colangiocarcinoma/genética , Colangiocarcinoma/patología , Colangiocarcinoma/metabolismo , Animales , Ratones , Humanos , Neoplasias de los Conductos Biliares/genética , Neoplasias de los Conductos Biliares/patología , Neoplasias de los Conductos Biliares/metabolismo , Ratones Noqueados , Metabolismo de los Lípidos , Línea Celular Tumoral , Proliferación Celular , Proteínas Proto-Oncogénicas c-akt/metabolismoRESUMEN
Acute Respiratory Distress Syndrome (ARDS) and Ulcerative Colitis (UC) are each characterized by tissue damage and uncontrolled inflammation. Neutrophils and other inflammatory cells play a primary role in disease progression by acutely responding to direct and indirect insults to tissue injury and by promoting inflammation through secretion of inflammatory cytokines and proteases. Vascular Endothelial Growth Factor (VEGF) is a ubiquitous signaling molecule that plays a key role in maintaining and promoting cell and tissue health, and is dysregulated in both ARDS and UC. Recent evidence suggests a role for VEGF in mediating inflammation, however, the molecular mechanism by which this occurs is not well understood. We recently showed that PR1P, a 12-amino acid peptide that binds to and upregulates VEGF, stabilizes VEGF from degradation by inflammatory proteases such as elastase and plasmin thereby limiting the production of VEGF degradation products (fragmented VEGF (fVEGF)). Here we show that fVEGF is a neutrophil chemoattractant in vitro and that PR1P can be used to reduce neutrophil migration in vitro by preventing the production of fVEGF during VEGF proteolysis. In addition, inhaled PR1P reduced neutrophil migration into airways following injury in three separate murine acute lung injury models including from lipopolysaccharide (LPS), bleomycin and acid. Reduced presence of neutrophils in the airways was associated with decreased pro-inflammatory cytokines (including TNF-α, IL-1ß, IL-6) and Myeloperoxidase (MPO) in broncho-alveolar lavage fluid (BALF). Finally, PR1P prevented weight loss and tissue injury and reduced plasma levels of key inflammatory cytokines IL-1ß and IL-6 in a rat TNBS-induced colitis model. Taken together, our data demonstrate that VEGF and fVEGF may each play separate and pivotal roles in mediating inflammation in ARDS and UC, and that PR1P, by preventing proteolytic degradation of VEGF and the production of fVEGF may represent a novel therapeutic approach to preserve VEGF signaling and inhibit inflammation in acute and chronic inflammatory diseases.
Asunto(s)
Lesión Pulmonar Aguda , Colitis Ulcerosa , Síndrome de Dificultad Respiratoria , Animales , Ratones , Ratas , Lesión Pulmonar Aguda/metabolismo , Colitis Ulcerosa/tratamiento farmacológico , Citocinas/metabolismo , Modelos Animales de Enfermedad , Inflamación/inducido químicamente , Interleucina-6 , Péptido Hidrolasas , Péptidos/efectos adversos , Síndrome de Dificultad Respiratoria/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
With age, skeletal muscle stem cells (MuSCs) activate out of quiescence more slowly and with increased death, leading to defective muscle repair. To explore the molecular underpinnings of these defects, we combined multiomics, single-cell measurements, and functional testing of MuSCs from young and old mice. The multiomics approach allowed us to assess which changes are causal, which are compensatory, and which are simply correlative. We identified glutathione (GSH) metabolism as perturbed in old MuSCs, with both causal and compensatory components. Contrary to young MuSCs, old MuSCs exhibit a population dichotomy composed of GSHhigh cells (comparable with young MuSCs) and GSHlow cells with impaired functionality. Mechanistically, we show that antagonism between NRF2 and NF-κB maintains this bimodality. Experimental manipulation of GSH levels altered the functional dichotomy of aged MuSCs. These findings identify a novel mechanism of stem cell aging and highlight glutathione metabolism as an accessible target for reversing MuSC aging.
Asunto(s)
Multiómica , Músculo Esquelético , Ratones , Animales , Músculo Esquelético/metabolismo , Células Madre/metabolismo , Senescencia Celular , Envejecimiento/fisiologíaRESUMEN
Short-term fasting is beneficial for the regeneration of multiple tissue types. However, the effects of fasting on muscle regeneration are largely unknown. Here, we report that fasting slows muscle repair both immediately after the conclusion of fasting as well as after multiple days of refeeding. We show that ketosis, either endogenously produced during fasting or a ketogenic diet or exogenously administered, promotes a deep quiescent state in muscle stem cells (MuSCs). Although deep quiescent MuSCs are less poised to activate, slowing muscle regeneration, they have markedly improved survival when facing sources of cellular stress. Furthermore, we show that ketone bodies, specifically ß-hydroxybutyrate, directly promote MuSC deep quiescence via a nonmetabolic mechanism. We show that ß-hydroxybutyrate functions as an HDAC inhibitor within MuSCs, leading to acetylation and activation of an HDAC1 target protein p53. Finally, we demonstrate that p53 activation contributes to the deep quiescence and enhanced resilience observed during fasting.
Asunto(s)
Ayuno , Proteína p53 Supresora de Tumor , Ácido 3-Hidroxibutírico , Ayuno/fisiología , Músculos , MioblastosRESUMEN
Lung progenitor cells are crucial for regeneration following injury, yet it is unclear whether lung progenitor cells can be functionally engrafted after transplantation. We transplanted organoid cells derived from alveolar type II (AT2) cells enriched by SCA1-negative status (SNO) or multipotent SCA1-positive progenitor cells (SPO) into injured mouse lungs. Transplanted SNO cells are retained in the alveolar regions, whereas SPO cells incorporate into airway and alveolar regions. Single-cell transcriptomics demonstrate that transplanted SNO cells are comparable to native AT2 cells. Transplanted SPO cells exhibit transcriptional hallmarks of alveolar and airway cells, as well as transitional cell states identified in disease. Transplanted cells proliferate after re-injury of recipient mice and retain organoid-forming capacity. Thus, lung epithelial organoid cells exhibit progenitor cell functions after reintroduction to the lung. This study reveals methods to interrogate lung progenitor cell potential and model transitional cell states relevant to pathogenic features of lung disease in vivo.
Asunto(s)
Organoides , Ataxias Espinocerebelosas , Animales , Diferenciación Celular , Células Epiteliales , Pulmón , Ratones , Células MadreRESUMEN
Mutant KRAS is a common driver in epithelial cancers. Nevertheless, molecular changes occurring early after activation of oncogenic KRAS in epithelial cells remain poorly understood. We compared transcriptional changes at single-cell resolution after KRAS activation in four sample sets. In addition to patient samples and genetically engineered mouse models, we developed organoid systems from primary mouse and human induced pluripotent stem cell-derived lung epithelial cells to model early-stage lung adenocarcinoma. In all four settings, alveolar epithelial progenitor (AT2) cells expressing oncogenic KRAS had reduced expression of mature lineage identity genes. These findings demonstrate the utility of our in vitro organoid approaches for uncovering the early consequences of oncogenic KRAS expression. This resource provides an extensive collection of datasets and describes organoid tools to study the transcriptional and proteomic changes that distinguish normal epithelial progenitor cells from early-stage lung cancer, facilitating the search for targets for KRAS-driven tumors.
Asunto(s)
Células Madre Pluripotentes Inducidas , Organoides , Animales , Humanos , Pulmón , Ratones , Proteómica , Proteínas Proto-Oncogénicas p21(ras)/genéticaRESUMEN
Excessive alcohol consumption, including binge drinking, is a common cause of fatty liver disease. Binge drinking rapidly induces hepatic steatosis, an early step in the pathogenesis of chronic liver injury. Despite its prevalence, the process by which excessive alcohol consumption promotes hepatic lipid accumulation remains unclear. Alcohol exerts potent effects on the brain, including hypothalamic neurons crucial for metabolic regulation. However, whether or not the brain plays a role in alcohol-induced hepatic steatosis is unknown. In the brain, alcohol increases extracellular levels of adenosine, a potent neuromodulator, and previous work implicates adenosine signaling as being important for the development of alcoholic fatty liver disease. Acute alcohol exposure also increases both the activity of agouti-related protein (AgRP)-expressing neurons and AgRP immunoreactivity. Here, we show that adenosine receptor A2B signaling in the brain modulates the extent of alcohol-induced fatty liver in mice and that both the AgRP neuropeptide and the sympathetic nervous system are indispensable for hepatic steatosis induced by bingelike alcohol consumption. Together, these results indicate that the brain plays an integral role in alcohol-induced hepatic lipid accumulation and that central adenosine signaling, hypothalamic AgRP, and the sympathetic nervous system are crucial mediators of this process.
Asunto(s)
Consumo Excesivo de Bebidas Alcohólicas/metabolismo , Hígado Graso Alcohólico/metabolismo , Hipotálamo/metabolismo , Metabolismo de los Lípidos/fisiología , Hígado/metabolismo , Neuronas/metabolismo , Proteína Relacionada con Agouti/metabolismo , Animales , Masculino , RatonesRESUMEN
The eukaryotic endoplasmic reticulum (ER) membrane contains essential complexes that oversee protein biogenesis and lipid metabolism, impacting nearly all aspects of cell physiology. The ER membrane protein complex (EMC) is a newly described transmembrane domain (TMD) insertase linked with various phenotypes, but whose clients and cellular responsibilities remain incompletely understood. We report that EMC deficiency limits the cellular boundaries defining cholesterol tolerance, reflected by diminished viability with limiting or excessive extracellular cholesterol. Lipidomic and proteomic analyses revealed defective biogenesis and concomitant loss of the TMD-containing ER-resident enzymes sterol-O-acyltransferase 1 (SOAT1) and squalene synthase (SQS, also known as FDFT1), which serve strategic roles in the adaptation of cells to changes in cholesterol availability. Insertion of the weakly hydrophobic tail-anchor (TA) of SQS into the ER membrane by the EMC ensures sufficient flux through the sterol biosynthetic pathway while biogenesis of polytopic SOAT1 promoted by the EMC provides cells with the ability to store free cholesterol as inert cholesteryl esters. By facilitating insertion of TMDs that permit essential mammalian sterol-regulating enzymes to mature accurately, the EMC is an important biogenic determinant of cellular robustness to fluctuations in cholesterol availability.This article has an associated First Person interview with the first author of the paper.
Asunto(s)
Colesterol/biosíntesis , Retículo Endoplásmico/enzimología , Farnesil Difosfato Farnesil Transferasa/metabolismo , Membranas Intracelulares/enzimología , Complejos Multienzimáticos/metabolismo , Esterol O-Aciltransferasa/metabolismo , Línea Celular Tumoral , Colesterol/genética , Retículo Endoplásmico/genética , Farnesil Difosfato Farnesil Transferasa/genética , Humanos , Complejos Multienzimáticos/genética , Esterol O-Aciltransferasa/genéticaRESUMEN
In aggressive tumors, alkylglyceronephosphate synthase (AGPS) controls cellular ether phospholipid utilization and metabolism to promote cancer cell proliferation and motility. SAR studies on the first-in-class AGPS inhibitor 1, discovered by our group, led to the 2,6-difluoro analog 2i which showed higher binding affinity than 1in vitro. In 231MFP cancer cells, 2i reduced ether lipids levels and cell migration rate. When tested in PC-3 and MDA-MB-231 cancer cells, 2i specifically impaired epithelial to mesenchymal transition (EMT) by modulating E-cadherin, Snail and MMP2 expression levels. Moreover, the combination of siRNAs against AGPS and 2i provided no additive effect, confirming that the modulation of 2i on EMT specifically relies on AGPS inhibition. Finally, this compound also affected cancer cell proliferation especially in MDA-MB-231â¯cells expressing higher AGPS level, whereas it provided negligible effects on MeT5A, a non-tumorigenic cell line, thus showing cancer specificity.
Asunto(s)
Transferasas Alquil y Aril/antagonistas & inhibidores , Transición Epitelial-Mesenquimal/efectos de los fármacos , Metabolismo de los Lípidos/efectos de los fármacos , Neoplasias/patología , Cadherinas/metabolismo , Línea Celular , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Humanos , Metaloproteinasa 2 de la Matriz/metabolismo , Neoplasias/tratamiento farmacológico , Factores de Transcripción de la Familia Snail/metabolismo , Relación Estructura-ActividadRESUMEN
N-acyl amino acids (NAAs) are a structurally diverse class of bioactive signaling lipids whose endogenous functions have largely remained uncharacterized. To clarify the physiologic roles of NAAs, we generated mice deficient in the circulating enzyme peptidase M20 domain-containing 1 (PM20D1). Global PM20D1-KO mice have dramatically reduced NAA hydrolase/synthase activities in tissues and blood with concomitant bidirectional dysregulation of endogenous NAAs. Compared with control animals, PM20D1-KO mice exhibit a variety of metabolic and pain phenotypes, including insulin resistance, altered body temperature in cold, and antinociceptive behaviors. Guided by these phenotypes, we identify N-oleoyl-glutamine (C18:1-Gln) as a key PM20D1-regulated NAA. In addition to its mitochondrial uncoupling bioactivity, C18:1-Gln also antagonizes certain members of the transient receptor potential (TRP) calcium channels including TRPV1. Direct administration of C18:1-Gln to mice is sufficient to recapitulate a subset of phenotypes observed in PM20D1-KO animals. These data demonstrate that PM20D1 is a dominant enzymatic regulator of NAA levels in vivo and elucidate physiologic functions for NAA signaling in metabolism and nociception.
Asunto(s)
Amidohidrolasas/metabolismo , Glutamina/metabolismo , Nocicepción/fisiología , Ácidos Oléicos/metabolismo , Transducción de Señal/fisiología , Amidohidrolasas/genética , Animales , Temperatura Corporal/fisiología , Glutamina/genética , Glutamina/farmacología , Ratones , Ratones Noqueados , Nocicepción/efectos de los fármacos , Ácidos Oléicos/genética , Ácidos Oléicos/farmacología , Canales Catiónicos TRPV/genética , Canales Catiónicos TRPV/metabolismoRESUMEN
Proper regulation of energy metabolism requires neurons in the central nervous system to respond dynamically to signals that reflect the body's energy reserve, and one such signal is leptin. Agouti-related protein (AgRP) is a hypothalamic neuropeptide that is markedly upregulated in leptin deficiency, a condition that is associated with severe obesity, diabetes, and hepatic steatosis. Because deleting AgRP in mice does not alter energy balance, we sought to determine whether AgRP plays an indispensable role in regulating energy and hepatic lipid metabolism in the sensitized background of leptin deficiency. We generated male mice that are deficient for both leptin and AgRP [double-knockout (DKO)]. DKO mice and ob/ob littermates had similar body weights, food intake, energy expenditure, and plasma insulin levels, although DKO mice surprisingly developed heightened hyperglycemia with advancing age. Overall hepatic lipid content was reduced in young prediabetic DKO mice, but not in the older diabetic counterparts. Intriguingly, however, both young and older DKO mice had an altered zonal distribution of hepatic lipids with reduced periportal lipid deposition. Moreover, leptin stimulated, whereas AgRP inhibited, hepatic sympathetic activity. Ablating sympathetic nerves to the liver, which primarily innervate the portal regions, produced periportal lipid accumulation in wild-type mice. Collectively, our results highlight AgRP as a regulator of hepatic sympathetic activity and metabolic zonation.
Asunto(s)
Proteína Relacionada con Agouti/fisiología , Metabolismo de los Lípidos/genética , Hígado/metabolismo , Proteína Relacionada con Agouti/genética , Animales , Hígado Graso/genética , Hígado Graso/metabolismo , Hígado Graso/patología , Leptina/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Obesos , Obesidad Mórbida/genética , Obesidad Mórbida/metabolismo , Obesidad Mórbida/patología , Distribución Tisular/genéticaRESUMEN
N-Acyl amino acids directly bind mitochondria and function as endogenous uncouplers of UCP1-independent respiration. We found that administration of N-acyl amino acids to mice improves glucose homeostasis and increases energy expenditure, indicating that this pathway might be useful for treating obesity and associated disorders. We report the full account of the synthesis and mitochondrial uncoupling bioactivity of lipidated N-acyl amino acids and their unnatural analogues. Unsaturated fatty acid chains of medium length and neutral amino acid head groups are required for optimal uncoupling activity on mammalian cells. A class of unnatural N-acyl amino acid analogues, characterized by isoindoline-1-carboxylate head groups (37), were resistant to enzymatic degradation by PM20D1 and maintained uncoupling bioactivity in cells and in mice.
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Aminoácidos/síntesis química , Aminoácidos/farmacología , Indoles/síntesis química , Indoles/farmacología , Mitocondrias/efectos de los fármacos , Amidohidrolasas/metabolismo , Animales , Línea Celular , Metabolismo Energético/efectos de los fármacos , Ácidos Grasos Insaturados/síntesis química , Ácidos Grasos Insaturados/farmacología , Glucosa/metabolismo , Homeostasis/efectos de los fármacos , Ratones , Consumo de Oxígeno/efectos de los fármacos , Estimulación Química , Relación Estructura-ActividadRESUMEN
There is limited knowledge about the metabolic reprogramming induced by cancer therapies and how this contributes to therapeutic resistance. Here we show that although inhibition of PI3K-AKT-mTOR signaling markedly decreased glycolysis and restrained tumor growth, these signaling and metabolic restrictions triggered autophagy, which supplied the metabolites required for the maintenance of mitochondrial respiration and redox homeostasis. Specifically, we found that survival of cancer cells was critically dependent on phospholipase A2 (PLA2) to mobilize lysophospholipids and free fatty acids to sustain fatty acid oxidation and oxidative phosphorylation. Consistent with this, we observed significantly increased lipid droplets, with subsequent mobilization to mitochondria. These changes were abrogated in cells deficient for the essential autophagy gene ATG5 Accordingly, inhibition of PLA2 significantly decreased lipid droplets, decreased oxidative phosphorylation, and increased apoptosis. Together, these results describe how treatment-induced autophagy provides nutrients for cancer cell survival and identifies novel cotreatment strategies to override this survival advantage.
Asunto(s)
Antineoplásicos/farmacología , Neoplasias/metabolismo , Transducción de Señal/efectos de los fármacos , Animales , Apoptosis , Autofagia , Benzamidas/farmacología , Línea Celular Tumoral , Respiración de la Célula/efectos de los fármacos , Supervivencia Celular , Compuestos Heterocíclicos con 3 Anillos/farmacología , Humanos , Gotas Lipídicas/metabolismo , Ratones , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Neoplasias/enzimología , Neoplasias/patología , Fosfatidilinositol 3-Quinasas/metabolismo , Inhibidores de las Quinasa Fosfoinosítidos-3 , Inhibidores de Fosfolipasa A2/farmacología , Fosfolípidos/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-akt/metabolismo , Pirimidinas/farmacología , Células Tumorales CultivadasRESUMEN
Lipid droplets (LDs) provide an "on-demand" source of fatty acids (FAs) that can be mobilized in response to fluctuations in nutrient abundance. Surprisingly, the amount of LDs increases during prolonged periods of nutrient deprivation. Why cells store FAs in LDs during an energy crisis is unknown. Our data demonstrate that mTORC1-regulated autophagy is necessary and sufficient for starvation-induced LD biogenesis. The ER-resident diacylglycerol acyltransferase 1 (DGAT1) selectively channels autophagy-liberated FAs into new, clustered LDs that are in close proximity to mitochondria and are lipolytically degraded. However, LDs are not required for FA delivery to mitochondria but instead function to prevent acylcarnitine accumulation and lipotoxic dysregulation of mitochondria. Our data support a model in which LDs provide a lipid buffering system that sequesters FAs released during the autophagic degradation of membranous organelles, reducing lipotoxicity. These findings reveal an unrecognized aspect of the cellular adaptive response to starvation, mediated by LDs.
Asunto(s)
Autofagia , Diacilglicerol O-Acetiltransferasa/metabolismo , Gotas Lipídicas/metabolismo , Mitocondrias/metabolismo , Aminoácidos/deficiencia , Animales , Autofagia/efectos de los fármacos , Carnitina/análogos & derivados , Carnitina/farmacología , Humanos , Marcaje Isotópico , Gotas Lipídicas/efectos de los fármacos , Diana Mecanicista del Complejo 1 de la Rapamicina , Ratones , Mitocondrias/efectos de los fármacos , Modelos Biológicos , Complejos Multiproteicos/metabolismo , Ácido Palmítico/metabolismo , Serina-Treonina Quinasas TOR/metabolismo , TriglicéridosRESUMEN
The mechanistic target of rapamycin complex 1 (mTORC1) protein kinase is a master growth regulator that becomes activated at the lysosome in response to nutrient cues. Here, we identify cholesterol, an essential building block for cellular growth, as a nutrient input that drives mTORC1 recruitment and activation at the lysosomal surface. The lysosomal transmembrane protein, SLC38A9, is required for mTORC1 activation by cholesterol through conserved cholesterol-responsive motifs. Moreover, SLC38A9 enables mTORC1 activation by cholesterol independently from its arginine-sensing function. Conversely, the Niemann-Pick C1 (NPC1) protein, which regulates cholesterol export from the lysosome, binds to SLC38A9 and inhibits mTORC1 signaling through its sterol transport function. Thus, lysosomal cholesterol drives mTORC1 activation and growth signaling through the SLC38A9-NPC1 complex.
Asunto(s)
Sistemas de Transporte de Aminoácidos/metabolismo , Proteínas Portadoras/metabolismo , Colesterol/metabolismo , Lisosomas/metabolismo , Complejos Multiproteicos/metabolismo , Proteínas Nucleares/metabolismo , Serina-Treonina Quinasas TOR/metabolismo , Secuencias de Aminoácidos , Sistemas de Transporte de Aminoácidos/genética , Animales , Transporte Biológico , Células CHO , HDL-Colesterol/metabolismo , Cricetulus , Activación Enzimática , Fibroblastos , Células HEK293 , Humanos , Diana Mecanicista del Complejo 1 de la Rapamicina , Ratones , Complejos Multiproteicos/antagonistas & inhibidores , Mutación , Transducción de Señal , Serina-Treonina Quinasas TOR/antagonistas & inhibidoresRESUMEN
Serine hydrolases are a large family of multifunctional enzymes known to influence obesity. Here, we performed activity-based protein profiling to assess the functional level of serine hydrolases in liver biopsies from lean and obese humans in order to gain mechanistic insight into the pathophysiology of metabolic disease. We identified reduced hepatic activity of carboxylesterase 2 (CES2) and arylacetamide deacetylase (AADAC) in human obesity. In primary human hepatocytes, CES2 knockdown impaired glucose storage and lipid oxidation. In mice, obesity reduced CES2, whereas adenoviral delivery of human CES2 reversed hepatic steatosis, improved glucose tolerance, and decreased inflammation. Lipidomic analysis identified a network of CES2-regulated lipids altered in human and mouse obesity. CES2 possesses triglyceride and diacylglycerol lipase activities and displayed an inverse correlation with HOMA-IR and hepatic diacylglycerol concentrations in humans. Thus, decreased CES2 is a conserved feature of obesity and plays a causative role in the pathogenesis of obesity-related metabolic disturbances.
Asunto(s)
Carboxilesterasa/metabolismo , Diglicéridos/metabolismo , Intolerancia a la Glucosa/patología , Obesidad/patología , Animales , Carboxilesterasa/antagonistas & inhibidores , Carboxilesterasa/genética , Hidrolasas de Éster Carboxílico/antagonistas & inhibidores , Hidrolasas de Éster Carboxílico/genética , Hidrolasas de Éster Carboxílico/metabolismo , Células Cultivadas , Dieta Alta en Grasa , Estrés del Retículo Endoplásmico , Vectores Genéticos/genética , Vectores Genéticos/metabolismo , Glucosa/metabolismo , Intolerancia a la Glucosa/metabolismo , Hepatocitos/citología , Hepatocitos/metabolismo , Humanos , Insulina/metabolismo , Proteínas Sustrato del Receptor de Insulina/genética , Proteínas Sustrato del Receptor de Insulina/metabolismo , Resistencia a la Insulina , Peroxidación de Lípido , Masculino , Ratones , Ratones Endogámicos C57BL , Obesidad/metabolismo , Serina-Treonina Quinasas TOR/genética , Serina-Treonina Quinasas TOR/metabolismoRESUMEN
Breast cancers possess fundamentally altered metabolism that fuels their pathogenicity. While many metabolic drivers of breast cancers have been identified, the metabolic pathways that mediate breast cancer malignancy and poor prognosis are less well understood. Here, we used a reactivity-based chemoproteomic platform to profile metabolic enzymes that are enriched in breast cancer cell types linked to poor prognosis, including triple-negative breast cancer (TNBC) cells and breast cancer cells that have undergone an epithelial-mesenchymal transition-like state of heightened malignancy. We identified glutathione S-transferase Pi 1 (GSTP1) as a novel TNBC target that controls cancer pathogenicity by regulating glycolytic and lipid metabolism, energetics, and oncogenic signaling pathways through a protein interaction that activates glyceraldehyde-3-phosphate dehydrogenase activity. We show that genetic or pharmacological inactivation of GSTP1 impairs cell survival and tumorigenesis in TNBC cells. We put forth GSTP1 inhibitors as a novel therapeutic strategy for combatting TNBCs through impairing key cancer metabolism and signaling pathways.
Asunto(s)
Gutatión-S-Transferasa pi/metabolismo , Leucina/análogos & derivados , Triazinas/farmacología , Neoplasias de la Mama Triple Negativas/metabolismo , Neoplasias de la Mama Triple Negativas/patología , Animales , Antineoplásicos/química , Antineoplásicos/farmacología , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Gutatión-S-Transferasa pi/antagonistas & inhibidores , Gutatión-S-Transferasa pi/genética , Humanos , Leucina/química , Leucina/farmacología , Ratones , Estructura Molecular , Neoplasias Experimentales/tratamiento farmacológico , Neoplasias Experimentales/metabolismo , Neoplasias Experimentales/patología , Relación Estructura-Actividad , Triazinas/química , Neoplasias de la Mama Triple Negativas/tratamiento farmacológico , Células Tumorales CultivadasRESUMEN
Many studies have identified metabolic pathways that underlie cellular transformation, but the metabolic drivers of cancer progression remain less well understood. The Hippo transducer pathway has been shown to confer malignant traits on breast cancer cells. In this study, we used metabolic mapping platforms to identify biochemical drivers of cellular transformation and malignant progression driven through RAS and the Hippo pathway in breast cancer and identified platelet-activating factor acetylhydrolase 1B3 (PAFAH1B3) as a key metabolic driver of breast cancer pathogenicity that is upregulated in primary human breast tumors and correlated with poor prognosis. Metabolomic profiling suggests that PAFAH1B3 inactivation attenuates cancer pathogenicity through enhancing tumor-suppressing signaling lipids. Our studies provide a map of altered metabolism that underlies breast cancer progression and put forth PAFAH1B3 as a critical metabolic node in breast cancer.