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1.
Mol Cell ; 73(5): 1001-1014.e8, 2019 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-30527540

RESUMO

In Parkinson's disease (PD), α-synuclein (αS) pathologically impacts the brain, a highly lipid-rich organ. We investigated how alterations in αS or lipid/fatty acid homeostasis affect each other. Lipidomic profiling of human αS-expressing yeast revealed increases in oleic acid (OA, 18:1), diglycerides, and triglycerides. These findings were recapitulated in rodent and human neuronal models of αS dyshomeostasis (overexpression; patient-derived triplication or E46K mutation; E46K mice). Preventing lipid droplet formation or augmenting OA increased αS yeast toxicity; suppressing the OA-generating enzyme stearoyl-CoA-desaturase (SCD) was protective. Genetic or pharmacological SCD inhibition ameliorated toxicity in αS-overexpressing rat neurons. In a C. elegans model, SCD knockout prevented αS-induced dopaminergic degeneration. Conversely, we observed detrimental effects of OA on αS homeostasis: in human neural cells, excess OA caused αS inclusion formation, which was reversed by SCD inhibition. Thus, monounsaturated fatty acid metabolism is pivotal for αS-induced neurotoxicity, and inhibiting SCD represents a novel PD therapeutic approach.


Assuntos
Antiparkinsonianos/farmacologia , Descoberta de Drogas/métodos , Inibidores Enzimáticos/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Metabolômica/métodos , Neurônios/efeitos dos fármacos , Doença de Parkinson/tratamento farmacológico , Estearoil-CoA Dessaturase/antagonistas & inibidores , alfa-Sinucleína/toxicidade , Animais , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/enzimologia , Caenorhabditis elegans/genética , Linhagem Celular , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/enzimologia , Córtex Cerebral/patologia , Diglicerídeos/metabolismo , Modelos Animais de Doenças , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/enzimologia , Neurônios Dopaminérgicos/patologia , Humanos , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Células-Tronco Pluripotentes Induzidas/enzimologia , Células-Tronco Pluripotentes Induzidas/patologia , Gotículas Lipídicas/efeitos dos fármacos , Gotículas Lipídicas/enzimologia , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Terapia de Alvo Molecular , Degeneração Neural , Células-Tronco Neurais/efeitos dos fármacos , Células-Tronco Neurais/enzimologia , Células-Tronco Neurais/patologia , Neurônios/enzimologia , Neurônios/patologia , Ácido Oleico/metabolismo , Doença de Parkinson/enzimologia , Doença de Parkinson/genética , Doença de Parkinson/patologia , Ratos Sprague-Dawley , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/genética , Estearoil-CoA Dessaturase/metabolismo , Triglicerídeos/metabolismo , alfa-Sinucleína/genética
2.
Am J Physiol Gastrointest Liver Physiol ; 323(4): G375-G386, 2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-36098401

RESUMO

Heavy alcohol consumption is the dominant risk factor for chronic pancreatitis (CP); however, treatment and prevention strategies for alcoholic chronic pancreatitis (ACP) remains limited. The present study demonstrates that ACP induction in C57BL/6 mice causes significant acinar cell injury, pancreatic stellate cell (PSC) activation, exocrine function insufficiency, and an increased fibroinflammatory response when compared with alcohol or CP alone. Although the withdrawal of alcohol during ACP recovery led to reversion of pancreatic damage, continued alcohol consumption with established ACP perpetuated pancreatic injury. In addition, phosphokinase array and Western blot analysis of ACP-induced mice pancreata revealed activation of the phosphatidylinositol 3 kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) and cyclic AMP response element binding protein (CREB) signaling pathways possibly orchestrating the fibroinflammatory program of ACP pathogenesis. Mice treated with urolithin A (Uro A, a gut-derived microbial metabolite) in the setting of ACP with continued alcohol intake (during the recovery period) showed suppression of AKT and P70S6K activation, and acinar damage was significantly reduced with a parallel reduction in pancreas-infiltrating macrophages and proinflammatory cytokine accumulation. These results collectively provide mechanistic insight into the impact of Uro A on attenuation of ACP severity through suppression of PI3K/AKT/mTOR signaling pathways and can be a useful therapeutic approach in patients with ACP with continuous alcohol intake.NEW & NOTEWORTHY Our novel findings presented here demonstrate the utility of Uro A as an effective therapeutic agent in attenuating alcoholic chronic pancreatitis (ACP) severity with alcohol continuation after established disease, through suppression of the PI3K/AKT/mTOR signaling pathway.


Assuntos
Pancreatite Alcoólica , Proteínas Proto-Oncogênicas c-akt , Camundongos , Animais , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , Proteínas Quinases S6 Ribossômicas 70-kDa/farmacologia , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Camundongos Endogâmicos C57BL , Serina-Treonina Quinases TOR/metabolismo , Transdução de Sinais , Pancreatite Alcoólica/patologia , Sirolimo/farmacologia , Citocinas/farmacologia , Consumo de Bebidas Alcoólicas , Mamíferos/metabolismo
3.
PLoS Biol ; 17(12): e3000242, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31805041

RESUMO

The ability to coordinate behavioral responses with metabolic status is fundamental to the maintenance of energy homeostasis. In numerous species including Caenorhabditis elegans and mammals, neural serotonin signaling regulates a range of food-related behaviors. However, the mechanisms that integrate metabolic information with serotonergic circuits are poorly characterized. Here, we identify metabolic, molecular, and cellular components of a circuit that links peripheral metabolic state to serotonin-regulated behaviors in C. elegans. We find that blocking the entry of fatty acyl coenzyme As (CoAs) into peroxisomal ß-oxidation in the intestine blunts the effects of neural serotonin signaling on feeding and egg-laying behaviors. Comparative genomics and metabolomics revealed that interfering with intestinal peroxisomal ß-oxidation results in a modest global transcriptional change but significant changes to the metabolome, including a large number of changes in ascaroside and phospholipid species, some of which affect feeding behavior. We also identify body cavity neurons and an ether-a-go-go (EAG)-related potassium channel that functions in these neurons as key cellular components of the circuitry linking peripheral metabolic signals to regulation of neural serotonin signaling. These data raise the possibility that the effects of serotonin on satiety may have their origins in feedback, homeostatic metabolic responses from the periphery.


Assuntos
Acil Coenzima A/metabolismo , Comportamento Alimentar/fisiologia , Serotonina/metabolismo , Animais , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Ácidos Graxos/metabolismo , Retroalimentação , Homeostase , Intestinos/fisiologia , Neurônios/metabolismo , Oxirredução , Peroxissomos/metabolismo , Transdução de Sinais
4.
PLoS Genet ; 14(3): e1007305, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29579048

RESUMO

The mechanisms by which the sensory environment influences metabolic homeostasis remains poorly understood. In this report, we show that oxygen, a potent environmental signal, is an important regulator of whole body lipid metabolism. C. elegans oxygen-sensing neurons reciprocally regulate peripheral lipid metabolism under normoxia in the following way: under high oxygen and food absence, URX sensory neurons are activated, and stimulate fat loss in the intestine, the major metabolic organ for C. elegans. Under lower oxygen conditions or when food is present, the BAG sensory neurons respond by repressing the resting properties of the URX neurons. A genetic screen to identify modulators of this effect led to the identification of a BAG-neuron-specific neuropeptide called FLP-17, whose cognate receptor EGL-6 functions in URX neurons. Thus, BAG sensory neurons counterbalance the metabolic effect of tonically active URX neurons via neuropeptide communication. The combined regulatory actions of these neurons serve to precisely tune the rate and extent of fat loss to the availability of food and oxygen, and provides an interesting example of the myriad mechanisms underlying homeostatic control.


Assuntos
Caenorhabditis elegans/metabolismo , Metabolismo dos Lipídeos , Neuropeptídeos/metabolismo , Oxigênio/metabolismo , Células Receptoras Sensoriais/metabolismo , Animais , Comunicação Celular , Guanilato Ciclase/metabolismo , Mucosa Intestinal/metabolismo , Transdução de Sinais
5.
J Neurogenet ; 34(3-4): 482-488, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32619378

RESUMO

This review article highlights our efforts to decode the role of the nervous system in regulating intestinal lipid metabolism in Caenorhabditis elegans. Capitalizing on the prescient and pioneering work of Sydney Brenner and John Sulston in establishing C. elegans as an immensely valuable model system, we have uncovered critical roles for oxygen sensing, population density sensing and food sensing in orchestrating the balance between storing lipids and utilizing them for energy in the intestine, the major organ for lipid metabolism in this model system. Our long-term goal is to reveal the integrative mechanisms and regulatory logic that underlies the complex relationship between genes, environment and internal state in the regulation of energy and whole-body physiology.


Assuntos
Caenorhabditis elegans/fisiologia , Metabolismo dos Lipídeos/fisiologia , Sistemas Neurossecretores/fisiologia , Animais , Peso Corporal , Proteínas de Caenorhabditis elegans/fisiologia , Metabolismo Energético , Comportamento Alimentar/fisiologia , Intestinos/inervação , Oxigênio , Densidade Demográfica , Serotonina/fisiologia , Inanição/metabolismo , Taquicininas/fisiologia
6.
PLoS Genet ; 13(5): e1006806, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28545126

RESUMO

It is now established that the central nervous system plays an important role in regulating whole body metabolism and energy balance. However, the extent to which sensory systems relay environmental information to modulate metabolic events in peripheral tissues has remained poorly understood. In addition, it has been challenging to map the molecular mechanisms underlying discrete sensory modalities with respect to their role in lipid metabolism. In previous work our lab has identified instructive roles for serotonin signaling as a surrogate for food availability, as well as oxygen sensing, in the control of whole body metabolism. In this study, we now identify a role for a pair of pheromone-sensing neurons in regulating fat metabolism in C. elegans, which has emerged as a tractable and highly informative model to study the neurobiology of metabolism. A genetic screen revealed that GPA-3, a member of the Gα family of G proteins, regulates body fat content in the intestine, the major metabolic organ for C. elegans. Genetic and reconstitution studies revealed that the potent body fat phenotype of gpa-3 null mutants is controlled from a pair of neurons called ADL(L/R). We show that cAMP functions as the second messenger in the ADL neurons, and regulates body fat stores via the neurotransmitter acetylcholine, from downstream neurons. We find that the pheromone ascr#3, which is detected by the ADL neurons, regulates body fat stores in a GPA-3-dependent manner. We define here a third sensory modality, pheromone sensing, as a major regulator of body fat metabolism. The pheromone ascr#3 is an indicator of population density, thus we hypothesize that pheromone sensing provides a salient 'denominator' to evaluate the amount of food available within a population and to accordingly adjust metabolic rate and body fat levels.


Assuntos
Caenorhabditis elegans/metabolismo , Metabolismo dos Lipídeos , Feromônios/metabolismo , Células Receptoras Sensoriais/metabolismo , Acetilcolina/metabolismo , Animais , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , AMP Cíclico/metabolismo , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/genética , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/metabolismo , Mucosa Intestinal/metabolismo , Sistemas do Segundo Mensageiro
7.
Annu Rev Physiol ; 77: 161-78, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25340962

RESUMO

Over the past decade, studies conducted in Caenorhabditis elegans have helped to uncover the ancient and complex origins of body fat regulation. This review highlights the powerful combination of genetics, pharmacology, and biochemistry used to study energy balance and the regulation of cellular fat metabolism in C. elegans. The complete wiring diagram of the C. elegans nervous system has been exploited to understand how the sensory nervous system regulates body fat and how food perception is coupled with the production of energy via fat metabolism. As a model organism, C. elegans also offers a unique opportunity to discover neuroendocrine factors that mediate direct communication between the nervous system and the metabolic tissues. The coming years are expected to reveal a wealth of information on the neuroendocrine control of body fat in C. elegans.


Assuntos
Tecido Adiposo/fisiologia , Caenorhabditis elegans/fisiologia , Metabolismo Energético/fisiologia , Animais , Metabolismo dos Lipídeos/fisiologia , Fenômenos Fisiológicos do Sistema Nervoso , Sistemas Neurossecretores/fisiologia
8.
Analyst ; 140(12): 3929-34, 2015 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-25939798

RESUMO

High throughput intracellular delivery strategies, electroporation, passive and TATHA2 facilitated diffusion of colloidal silver nanoparticles (AgNPs) are investigated for cellular toxicity and uptake using state-of-art analytical techniques. The TATHA2 facilitated approach efficiently delivered high payload with no toxicity, pre-requisites for intracellular applications of plasmonic metal nanoparticles (PMNPs) in sensing and therapeutics.


Assuntos
Técnicas Biossensoriais , Imunoensaio , Espaço Intracelular/metabolismo , Nanopartículas , Peptídeos/química , Prata/química , Prata/metabolismo , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/metabolismo , Transporte Biológico , Eletroporação
9.
PLoS Biol ; 9(12): e1001219, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22180729

RESUMO

Bardet-Biedl syndrome, BBS, is a rare autosomal recessive disorder with clinical presentations including polydactyly, retinopathy, hyperphagia, obesity, short stature, cognitive impairment, and developmental delays. Disruptions of BBS proteins in a variety of organisms impair cilia formation and function and the multi-organ defects of BBS have been attributed to deficiencies in various cilia-associated signaling pathways. In C. elegans, bbs genes are expressed exclusively in the sixty ciliated sensory neurons of these animals and bbs mutants exhibit sensory defects as well as body size, feeding, and metabolic abnormalities. Here we show that in contrast to many other cilia-defective mutants, C. elegans bbs mutants exhibit increased release of dense-core vesicles and organism-wide phenotypes associated with enhanced activities of insulin, neuropeptide, and biogenic amine signaling pathways. We show that the altered body size, feeding, and metabolic abnormalities of bbs mutants can be corrected to wild-type levels by abrogating the enhanced secretion of dense-core vesicles without concomitant correction of ciliary defects. These findings expand the role of BBS proteins to the regulation of dense-core-vesicle exocytosis and suggest that some features of Bardet-Biedl Syndrome may be caused by excessive neuroendocrine secretion.


Assuntos
Síndrome de Bardet-Biedl/fisiopatologia , Tamanho Corporal/genética , Cílios/fisiologia , Comportamento Alimentar/fisiologia , Animais , Síndrome de Bardet-Biedl/genética , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/metabolismo , Linhagem Celular , Insulina/metabolismo , Secreção de Insulina , Glicoproteínas de Membrana/metabolismo , Camundongos , Neuropeptídeos/metabolismo , Proteínas Tirosina Fosfatases/metabolismo , Serotonina/fisiologia
10.
Nat Commun ; 15(1): 6869, 2024 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-39127676

RESUMO

In C. elegans mechanisms by which peripheral organs relay internal state information to the nervous system remain unknown, although strong evidence suggests that such signals do exist. Here we report the discovery of a peptide of the ancestral insulin superfamily called INS-7 that functions as an enteroendocrine peptide and is secreted from specialized cells of the intestine. INS-7 secretion is stimulated by food withdrawal, increases during fasting and acts as a bona fide gut-to-brain peptide that attenuates the release of a neuropeptide that drives fat loss in the periphery. Thus, INS-7 functions as a homeostatic signal from the intestine that gates the neuronal drive to stimulate fat loss during food shortage. Mechanistically, INS-7 functions as an antagonist at the canonical DAF-2 receptor and functions via FOXO and AMPK signaling in ASI neurons. Phylogenetic analysis suggests that INS-7 bears greater resemblance to members of the broad insulin/relaxin superfamily than to conventional mammalian insulin and IGF peptides. The discovery of an endogenous insulin antagonist secreted by specialized intestinal cells with enteroendocrine functions suggests unexpected and important properties of the intestine and its role in directing neuronal functions.


Assuntos
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Homeostase , Insulina , Neurônios , Animais , Neurônios/metabolismo , Neurônios/efeitos dos fármacos , Insulina/metabolismo , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Receptor de Insulina/metabolismo , Receptor de Insulina/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Encéfalo/metabolismo , Encéfalo/efeitos dos fármacos , Neuropeptídeos/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Fatores de Transcrição Forkhead/genética , Intestinos , Filogenia , Jejum , Mucosa Intestinal/metabolismo
11.
bioRxiv ; 2024 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-38903082

RESUMO

BACKGROUND AND AIMS: In vivo induction of alcoholic chronic pancreatitis (ACP) causes significant acinar damage, increased fibroinflammatory response, and heightened activation of cyclic response element binding protein 1 (CREB) when compared with alcohol (A) or chronic pancreatitis (CP) mediated pancreatic damage. However, the study elucidating the cooperative interaction between CREB and the oncogenic Kras G12D/+ (Kras*) in promoting pancreatic cancer progression with ACP remains unexplored. METHODS: Experimental ACP induction was established in multiple mouse models, followed by euthanization of the animals at various time intervals during the recovery periods. Tumor latency was determined in these mice cohorts. Here, we established CREB deletion (Creb fl/fl ) in Ptf1a CreERTM/+ ;LSL-Kras G12D+/-(KC) genetic mouse models (KCC-/-). Western blot, phosphokinase array, and qPCR were used to analyze the pancreata of Ptf1a CreERTM+/-, KC and KCC -/- mice. The pancreata of ACP-induced KC mice were subjected to single-cell RNA sequencing (scRNAseq). Further studies involved conducting lineage tracing and acinar cell explant cultures. RESULTS: ACP induction in KC mice had detrimental effects on the pancreatic damage repair mechanism. The persistent existence of acinar cell-derived ductal lesions demonstrated a prolonged state of hyperactivated CREB. Persistent CREB activation leads to acinar cell reprogramming and increased pro-fibrotic inflammation in KC mice. Acinar-specific Creb ablation reduced advanced PanINs lesions, hindered tumor progression, and restored acinar cell function in ACP-induced mouse models. CONCLUSIONS: Our findings demonstrate that CREB cooperates with Kras* to perpetuate an irreversible ADM and PanIN formation. Moreover, CREB sustains oncogenic activity to promote the progression of premalignant lesions toward cancer in the presence of ACP.

12.
bioRxiv ; 2023 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-37961386

RESUMO

In C. elegans mechanisms by which peripheral organs relay internal state information to the nervous system remain unknown, although strong evidence suggests that such signals do exist. Here we report the discovery of a peptide of the ancestral insulin superfamily called INS-7 that functions as an enteroendocrine peptide and is secreted from specialized cells of the intestine. INS-7 secretion increases during fasting, and acts as a bona fide gut-to-brain homeostatic signal that attenuates neuronally induced fat loss during food shortage. INS-7 functions as an antagonist at the canonical DAF-2 receptor in the nervous system, and phylogenetic analysis suggests that INS-7 bears greater resemblance to members of the broad insulin/relaxin superfamily than to conventional mammalian insulin and IGF peptides. The discovery of an endogenous insulin antagonist secreted by specialized intestinal cell with enteroendocrine functions suggests that much remains to be learned about the intestine and its role in directing neuronal functions.

13.
Cancer Res Commun ; 3(7): 1224-1236, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37448553

RESUMO

Pancreatic ductal adenocarcinoma (PDAC) is a significant contributor to cancer-related morbidity and mortality, and it is known for its resistance to conventional treatment regimens, including chemotherapy and immune checkpoint blockade (ICB)-based therapies. We have previously shown that Urolithin A (Uro A), a gut microbial metabolite derived from pomegranates, can target and inhibit KRAS-dependent PI3K/AKT/mTOR signaling pathways to overcome therapeutic resistance and improve survival in PDAC. However, the effect of Uro A on the tumor immune microenvironment and its ability to enhance ICB efficacy has not been explored. This study demonstrates that Uro A treatment reduces stromal fibrosis and reinvigorates the adaptive T-cell immune response to overcome resistance to PD-1 blockade in a genetically engineered mouse model (GEMM) of PDAC. Flow cytometric-based analysis of Uro A-treated mouse tumors revealed a significant attenuation of immunosuppressive tumor-associated M2-like macrophages with a concurrent increase in the infiltration of CD4+ and CD8+ T cells with memory-like phenotype along with reduced expression of the exhaustion-associated protein, PD-1. Importantly, the combination of Uro A treatment with anti-PD-1 immunotherapy promoted enhancement of the antitumor response with increased infiltration of CD4+ Th1 cells, ultimately resulting in a remarkable improvement in overall survival in GEMM of PDAC. Overall, our findings provide preclinical evidence for the potential of Uro A as a novel therapeutic agent to increase sensitivity to immunotherapy in PDAC and warrant further mechanistic exploration in preclinical and clinical studies. Significance: Immunotherapeutic agents are ineffective against pancreatic cancer, mainly due to the immunosuppressive tumor microenvironment and stromal desmoplasia. Our current study demonstrates the therapeutic utility of a novel gut microbial metabolite, Uro A, to remodel the stromal-immune microenvironment and improve overall survival with anti-PD-1 therapy in pancreatic cancer.


Assuntos
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Camundongos , Animais , Inibidores de Checkpoint Imunológico/farmacologia , Linfócitos T CD8-Positivos/metabolismo , Fosfatidilinositol 3-Quinases/farmacologia , Neoplasias Pancreáticas/tratamento farmacológico , Carcinoma Ductal Pancreático/tratamento farmacológico , Microambiente Tumoral
14.
Nat Methods ; 5(8): 673-8, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18668035

RESUMO

We are creating families of designer G protein-coupled receptors (GPCRs) to allow for precise spatiotemporal control of GPCR signaling in vivo. These engineered GPCRs, called receptors activated solely by synthetic ligands (RASSLs), are unresponsive to endogenous ligands but can be activated by nanomolar concentrations of pharmacologically inert, drug-like small molecules. Currently, RASSLs exist for the three major GPCR signaling pathways (G(s), G(i) and G(q)). We review these advances here to facilitate the use of these powerful and diverse tools.


Assuntos
Engenharia de Proteínas/métodos , Receptores Acoplados a Proteínas G/análise , Receptores Acoplados a Proteínas G/metabolismo , Transdução de Sinais , Animais , Evolução Molecular , Humanos , Ligantes , Ligação Proteica , Receptores Acoplados a Proteínas G/química , Receptores Acoplados a Proteínas G/genética
15.
Nat Cell Biol ; 4(7): 513-8, 2002 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12080345

RESUMO

In gradients of external chemo-attractant, mammalian neutrophilic leukocytes (neutrophils) and Dictyostelium discoideum amoebae adopt a polarized morphology and selectively accumulate lipid products of phosphatidylinositol-3-OH kinases (PI(3)Ks), including PtdIns(3,4,5)P(3), at their up-gradient edges; the internal PtdIns(3,4,5)P(3) gradient substantially exceeds that of the external attractant. An accompanying report presents evidence for a positive feedback loop that amplifies the gradient of internal signal: PtdIns(3,4,5)P(3) at the leading edge stimulates its own accumulation by inducing activation of one or more Rho GTPases (Rac, Cdc42, and/or Rho), which in turn increase PtdIns(3,4,5)P(3) accumulation. Here we show that interruption of this feedback by treatment with PI(3)K inhibitors reduces the size and stability of pseudopods and causes cells to migrate in jerky trajectories that deviate more from the up-gradient direction than do those of controls. Moreover, amplification of the internal PtdIns(3,4,5)P(3) gradient is markedly impaired by latrunculin or jasplakinolide, toxins that inhibit polymerization or depolymerization of actin, respectively. Thus reciprocal interplay between PtdIns(3,4,5)P(3) and polymerized actin initiates and maintains the asymmetry of intracellular signals responsible for cell polarity and directed motility.


Assuntos
Movimento Celular , Polaridade Celular , Depsipeptídeos , Neutrófilos/citologia , Fosfatidilinositol 3-Quinases/metabolismo , Fosfatos de Fosfatidilinositol/metabolismo , Animais , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Quimiotaxia/efeitos dos fármacos , Dictyostelium , Inibidores Enzimáticos/farmacologia , Retroalimentação Fisiológica , Células HL-60 , Humanos , Toxinas Marinhas/farmacologia , Peptídeos Cíclicos/farmacologia , Pseudópodes/efeitos dos fármacos , Tiazóis/farmacologia , Tiazolidinas
16.
Nanomedicine ; 7(3): 324-32, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21094277

RESUMO

The purpose of this study was to compare the cellular uptake and cytotoxicity of targeted and nontargeted doxorubicin (DOX)-loaded poly(d,l-lactide co-glycolide) (PLGA) nanoparticle (NP) drug delivery systems in drug-resistant ovarian (SKOV-3) and uterine (MES-SA/Dx5) cancer cell lines. The cellular uptakes of DOX from nonconjugated DOX-loaded NPs (DNPs) and from HER-2 antibody-conjugated DOX-loaded NPs (ADNPs) in MES-SA/Dx5 cancer cells were higher compared to free DOX. Results also showed higher uptake of DOX from ADNPs in SKOV-3 cells compared with both free DOX and DNPs treatment. Cytotoxicity results at 10 µM extracellular DOX concentration were consistent with the cellular uptake results. Our study concludes that cellular uptake and cytotoxicity of DOX can be improved in MES-SA/Dx5 cells by loading DOX into PLGA NPs. DNPs targeted to membrane receptors may enhance cellular uptake and cytotoxicity in SKOV-3 cells. FROM THE CLINICAL EDITOR: The authors of this study compare the cellular uptake and cytotoxicity of targeted and nontargeted doxorubicin loaded PLGA nanoparticle delivery systems in drug-resistant ovarian and uterine cancer cell lines, concluding that cellular uptake and cytotoxicity of doxorubicin can be improved by the proposed methods.


Assuntos
Portadores de Fármacos/toxicidade , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Endocitose/efeitos dos fármacos , Anticorpos/imunologia , Transporte Biológico/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Química Farmacêutica , Doxorrubicina/farmacologia , Humanos , Espaço Intracelular/efeitos dos fármacos , Espaço Intracelular/metabolismo , Cinética , Luz , Microscopia Confocal , Nanopartículas/química , Tamanho da Partícula , Espalhamento de Radiação , Eletricidade Estática , Frações Subcelulares/metabolismo
17.
Elife ; 102021 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-33635271

RESUMO

Making choices about food affects the metabolism and lifespan of fruit flies.


Assuntos
Envelhecimento , Drosophila melanogaster , Animais , Drosophila , Drosophila melanogaster/genética , Longevidade
18.
Mol Cancer Ther ; 20(7): 1246-1256, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34001634

RESUMO

Activating KRAS mutations, a defining feature of pancreatic ductal adenocarcinoma (PDAC), promote tumor growth in part through the activation of cyclin-dependent kinases (CDK) that induce cell-cycle progression. p16INK4a (p16), encoded by the gene CDKN2A, is a potent inhibitor of CDK4/6 and serves as a critical checkpoint of cell proliferation. Mutations in and subsequent loss of the p16 gene occur in PDAC at a rate higher than that reported in any other tumor type and results in Rb inactivation and unrestricted cellular growth. Therefore, strategies targeting downstream RAS pathway effectors combined with CDK4/6 inhibition (CDK4/6i) may have the potential to improve outcomes in this disease. Herein, we show that expression of p16 is markedly reduced in PDAC tumors compared with normal pancreatic or pre-neoplastic tissues. Combined MEK inhibition (MEKi) and CDK4/6i results in sustained downregulation of both ERK and Rb phosphorylation and a significant reduction in cell proliferation compared with monotherapy in human PDAC cells. MEKi with CDK4/6i reduces tumor cell proliferation by promoting senescence-mediated growth arrest, independent of apoptosis in vitro We show that combined MEKi and CDK4/6i treatment attenuates tumor growth in xenograft models of PDAC and improves overall survival over 200% compared with treatment with vehicle or individual agents alone in Ptf1acre/+ ;LSL-KRASG12D/+ ;Tgfbr2flox/flox (PKT) mice. Histologic analysis of PKT tumor lysates reveal a significant decrease in markers of cell proliferation and an increase in senescence-associated markers without any significant change in apoptosis. These results demonstrate that combined targeting of both MEK and CDK4/6 represents a novel therapeutic strategy to synergistically reduce tumor growth through induction of cellular senescence in PDAC.


Assuntos
Senescência Celular/efeitos dos fármacos , Quinase 4 Dependente de Ciclina/metabolismo , Quinase 6 Dependente de Ciclina/metabolismo , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Transdução de Sinais/efeitos dos fármacos , Animais , Carcinoma Ductal Pancreático/tratamento farmacológico , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Quinase 4 Dependente de Ciclina/antagonistas & inibidores , Quinase 6 Dependente de Ciclina/antagonistas & inibidores , Modelos Animais de Doenças , Sinergismo Farmacológico , Regulação Neoplásica da Expressão Gênica , Genes p16 , Humanos , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Inibidores de Proteínas Quinases/uso terapêutico , Ensaios Antitumorais Modelo de Xenoenxerto
19.
Mol Cancer Ther ; 20(11): 2280-2290, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34518296

RESUMO

A hallmark of pancreatic ductal adenocarcinoma (PDAC) is the presence of a dense, desmoplastic stroma and the consequent altered interactions between cancer cells and their surrounding tumor microenvironment (TME) that promote disease progression, metastasis, and chemoresistance. We have previously shown that IL6 secreted from pancreatic stellate cells (PSC) stimulates the activation of STAT3 signaling in tumor cells, an established mechanism of therapeutic resistance in PDAC. We have now identified the tumor cell-derived cytokine IL1α as an upstream mediator of IL6 release from PSCs that is involved in STAT3 activation within the TME. Herein, we show that IL1α is overexpressed in both murine and human PDAC tumors and engages with its cognate receptor IL1R1, which is strongly expressed on stromal cells. Further, we show that IL1R1 inhibition using anakinra (recombinant IL1 receptor antagonist) significantly reduces stromal-derived IL6, thereby suppressing IL6-dependent STAT3 activation in human PDAC cell lines. Anakinra treatment results in significant reduction in IL6 and activated STAT3 levels in pancreatic tumors from Ptf1aCre/+;LSL-KrasG12D/+; Tgfbr2flox/flox (PKT) mice. Additionally, the combination of anakinra with cytotoxic chemotherapy significantly extends overall survival compared with vehicle treatment or anakinra monotherapy in this aggressive genetic mouse model of PDAC. These data highlight the importance of IL1 in mediating tumor-stromal IL6/STAT3 cross-talk in the TME and provide a preclinical rationale for targeting IL1 signaling as a therapeutic strategy in PDAC.


Assuntos
Interleucina-6/metabolismo , Neoplasias Pancreáticas/genética , Receptores de Interleucina-1/antagonistas & inibidores , Animais , Humanos , Camundongos , Neoplasias Pancreáticas/patologia , Transdução de Sinais
20.
Pharm Res ; 27(10): 2242-53, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20694526

RESUMO

PURPOSE: To test the effectiveness of a dual-agent-loaded PLGA nanoparticulate drug delivery system containing doxorubicin (DOX) and indocyanine green (ICG) in a DOX-sensitive cell line and two resistant cell lines that have different resistance mechanisms. METHODS: The DOX-sensitive MES-SA uterine sarcoma cell line was used as a negative control. The two resistant cell lines were uterine sarcoma MES-SA/Dx5, which overexpresses the multidrug resistance exporter P-glycoprotein, and ovarian carcinoma SKOV-3, which is less sensitive to doxorubicin due to a p53 gene mutation. The cellular uptake, subcellular localization and cytotoxicity of the two agents when delivered via nanoparticles (NPs) were compared to their free-form administration. RESULTS: The cellular uptake and cytotoxicity of DOX delivered by NPs were comparable to the free form in MES-SA and SKOV-3, but much higher in MES-SA/Dx5, indicating the capability of the NPs to overcome P-glycoprotein resistance mechanisms. NP-encapsulated ICG showed slightly different subcellular localization, but similar fluorescence intensity when compared to free ICG, and retained the ability to generate heat for hyperthermia delivery. CONCLUSION: The dual-agent-loaded system allowed for the simultaneous delivery of hyperthermia and chemotherapy, and this combinational treatment greatly improved cytotoxicity in MES-SA/Dx5 cells and to a lesser extent in SKOV-3 cells.


Assuntos
Antineoplásicos/administração & dosagem , Doxorrubicina/administração & dosagem , Portadores de Fármacos/química , Ácido Láctico/química , Nanopartículas/química , Compostos Orgânicos/administração & dosagem , Ácido Poliglicólico/química , Antineoplásicos/farmacocinética , Transporte Biológico , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Doxorrubicina/farmacocinética , Doxorrubicina/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Feminino , Humanos , Hipertermia Induzida/métodos , Microscopia Eletrônica de Varredura , Fenômenos Ópticos , Compostos Orgânicos/farmacocinética , Compostos Orgânicos/farmacologia , Tamanho da Partícula , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Solubilidade , Propriedades de Superfície
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