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1.
Stem Cells ; 40(8): 736-750, 2022 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-35535819

RESUMO

Acute myeloid leukemia (AML) is an aggressive malignancy of the bone marrow with 5-year overall survival of less than 10% in patients over the age of 65. Limited progress has been made in the patient outcome because of the inability to selectively eradicate the leukemic stem cells (LSC) driving the refractory and relapsed disease. Herein, we investigated the role of the reprogramming factor KLF4 in AML because of its critical role in the self-renewal and stemness of embryonic and cancer stem cells. Using a conditional Cre-lox Klf4 deletion system and the MLL-AF9 retroviral mouse model, we demonstrated that loss-of-KLF4 does not significantly affect the induction of leukemia but markedly decreased the frequency of LSCs evaluated in limiting-dose transplantation studies. Loss of KLF4 in leukemic granulocyte-macrophage progenitors (L-GMP), a population enriched for AML LSCs, showed lessened clonogenicity and percentage in the G2/M phase of the cell cycle. RNAseq analysis of purified L-GMPs revealed decreased expression of stemness genes and MLL-target genes and upregulation of the RNA sensing helicase DDX58. However, silencing of DDX58 in KLF4 knockout leukemia indicated that DDX58 is not mediating this phenotype. CRISPR/Cas9 deletion of KLF4 in MOLM13 cell line and AML patient-derived xenograft cells showed impaired expansion in vitro and in vivo associated with a defective G2/M checkpoint. Collectively, our data suggest a mechanism in which KLF4 promotes leukemia progression by establishing a gene expression profile in AML LSCs supporting cell division and stemness.


Assuntos
Fator 4 Semelhante a Kruppel , Leucemia Mieloide Aguda , Animais , Medula Óssea/patologia , Modelos Animais de Doenças , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Camundongos , Proteína de Leucina Linfoide-Mieloide/metabolismo , Células-Tronco Neoplásicas/metabolismo , Proteínas de Fusão Oncogênica/metabolismo
2.
J Allergy Clin Immunol ; 132(5): 1205-1214.e9, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24021572

RESUMO

BACKGROUND: Sphingosine-1-phosphate receptor 2 (S1P(2)) is expressed in vascular endothelial cells (ECs). However, the role of S1P(2) in vascular barrier integrity and anaphylaxis is not well understood. Endothelial nitric oxide synthase (eNOS) generates nitric oxide to mediate vascular leakage, compromising survival in patients with anaphylaxis. We recently observed that endothelial S1P(2) inhibits Akt, an activating kinase of eNOS. OBJECTIVE: We tested the hypothesis that endothelial S1P(2) might suppress eNOS, exerting a protective effect against endothelial barrier disruption and anaphylaxis. METHODS: Mice deficient in S1P(2) and eNOS underwent antigen challenge or platelet-activating factor (PAF) injection. Analyses were performed to examine vascular permeability and the underlying mechanisms. RESULTS: S1pr2 deletion augmented vascular leakage and lethality after either antigen challenge or PAF injection. PAF injection induced activation of Akt and eNOS in the aortas and lungs of S1pr2-null mice, which were augmented compared with values seen in wild-type mice. Consistently, PAF-induced increase in cyclic guanosine monophosphate levels in the aorta was enhanced in S1pr-null mice. Genetic Nos3 deletion or pharmacologic eNOS blockade protected S1pr2-null mice from aggravation of barrier disruption after antigen challenge and PAF injection. ECs isolated from S1pr2-null mice exhibited greater stimulation of Akt and eNOS, with enhanced nitric oxide production in response to sphingosine-1-phosphate or PAF, compared with that seen in wild-type ECs. Moreover, S1pr2-deficient ECs showed more severe disassembly of adherens junctions with augmented S-nitrosylation of ß-catenin in response to PAF, which was restored by pharmacologic eNOS blockade. CONCLUSION: S1P(2) diminishes harmful robust eNOS stimulation and thereby attenuates vascular barrier disruption, suggesting potential usefulness of S1P(2) agonists as novel therapeutic agents for anaphylaxis.


Assuntos
Anafilaxia/metabolismo , Óxido Nítrico Sintase Tipo III/antagonistas & inibidores , Receptores de Lisoesfingolipídeo/metabolismo , Junções Aderentes/metabolismo , Anafilaxia/genética , Anafilaxia/mortalidade , Animais , Aorta/imunologia , Aorta/metabolismo , Permeabilidade Capilar/genética , Permeabilidade Capilar/imunologia , Modelos Animais de Doenças , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Ativação Enzimática , Deleção de Genes , Pulmão/imunologia , Pulmão/metabolismo , Camundongos , Camundongos Knockout , NG-Nitroarginina Metil Éster/farmacologia , Óxido Nítrico Sintase Tipo III/genética , Óxido Nítrico Sintase Tipo III/metabolismo , Fator de Ativação de Plaquetas/farmacologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores de Lisoesfingolipídeo/genética , Transdução de Sinais , beta Catenina/metabolismo
3.
JCI Insight ; 9(5)2024 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-38456501

RESUMO

Efficient clearance and degradation of apoptotic cardiomyocytes by macrophages (collectively termed efferocytosis) is critical for inflammation resolution and restoration of cardiac function after myocardial ischemia/reperfusion (I/R). Here, we define secreted and transmembrane protein 1a (Sectm1a), a cardiac macrophage-enriched gene, as a modulator of macrophage efferocytosis in I/R-injured hearts. Upon myocardial I/R, Sectm1a-KO mice exhibited impaired macrophage efferocytosis, leading to massive accumulation of apoptotic cardiomyocytes, cardiac inflammation, fibrosis, and consequently, exaggerated cardiac dysfunction. By contrast, therapeutic administration of recombinant SECTM1A protein significantly enhanced macrophage efferocytosis and improved cardiac function. Mechanistically, SECTM1A could elicit autocrine effects on the activation of glucocorticoid-induced TNF receptor (GITR) at the surface of macrophages, leading to the upregulation of liver X receptor α (LXRα) and its downstream efferocytosis-related genes and lysosomal enzyme genes. Our study suggests that Sectm1a-mediated activation of the Gitr/LXRα axis could be a promising approach to enhance macrophage efferocytosis for the treatment of myocardial I/R injury.


Assuntos
Traumatismo por Reperfusão Miocárdica , Fagocitose , Camundongos , Animais , Eferocitose , Apoptose , Macrófagos/metabolismo , Inflamação/metabolismo , Proteínas de Membrana/metabolismo , Traumatismo por Reperfusão Miocárdica/metabolismo , Reperfusão
4.
Lab Invest ; 93(10): 1115-27, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23938603

RESUMO

Vascular tumors are endothelial cell neoplasms whose cellular and molecular mechanisms, leading to tumor formation, are poorly understood, and current therapies have limited efficacy with significant side effects. We have investigated mechanistic (mammalian) target of rapamycin (mTOR) signaling in benign and malignant vascular tumors, and the effects of mTOR kinase inhibitor as a potential therapy for these lesions. Human vascular tumors (infantile hemangioma and angiosarcoma) were analyzed by immunohistochemical stains and western blot for the phosphorylation of p70 S6-kinase (S6K) and S6 ribosomal protein (S6), which are activated downstream of mTOR complex-1 (mTORC1). To assess the function of S6K, tumor cells with genetic knockdown of S6K were analyzed for cell proliferation and migration. The effects of topical rapamycin, an mTOR inhibitor, on mTORC1 and mTOR complex-2 (mTORC2) activities, as well as on tumor growth and migration, were determined. Vascular tumors showed increased activation of S6K and S6. Genetic knockdown of S6K resulted in reduced tumor cell proliferation and migration. Rapamycin fully inhibited mTORC1 and partially inhibited mTORC2 activities, including the phosphorylation of Akt (serine 473) and PKCα, in vascular tumor cells. Rapamycin significantly reduced vascular tumor growth in vitro and in vivo. As a potential localized therapy for cutaneous vascular tumors, topically applied rapamycin effectively reduced tumor growth with limited systemic drug absorption. These findings reveal the importance of mTOR signaling pathways in benign and malignant vascular tumors. The mTOR pathway is an important therapeutic target in vascular tumors, and topical mTOR inhibitors may provide an alternative and well-tolerated therapy for the treatment of cutaneous vascular lesions.


Assuntos
Antibióticos Antineoplásicos/uso terapêutico , Hemangioma Capilar/tratamento farmacológico , Hemangiossarcoma/tratamento farmacológico , Síndromes Neoplásicas Hereditárias/tratamento farmacológico , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Quinases S6 Ribossômicas 70-kDa/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Sirolimo/uso terapêutico , Administração Tópica , Adolescente , Adulto , Idoso , Animais , Antibióticos Antineoplásicos/administração & dosagem , Antibióticos Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Criança , Feminino , Hemangioma Capilar/epidemiologia , Hemangioma Capilar/metabolismo , Hemangioma Capilar/patologia , Hemangiossarcoma/epidemiologia , Hemangiossarcoma/metabolismo , Hemangiossarcoma/patologia , Humanos , Lactente , Masculino , Alvo Mecanístico do Complexo 1 de Rapamicina , Alvo Mecanístico do Complexo 2 de Rapamicina , Camundongos , Camundongos Nus , Complexos Multiproteicos/antagonistas & inibidores , Complexos Multiproteicos/metabolismo , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Síndromes Neoplásicas Hereditárias/epidemiologia , Síndromes Neoplásicas Hereditárias/metabolismo , Síndromes Neoplásicas Hereditárias/patologia , Inibidores de Proteínas Quinases/administração & dosagem , Inibidores de Proteínas Quinases/farmacologia , Proteínas Quinases S6 Ribossômicas 70-kDa/genética , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , Sirolimo/administração & dosagem , Sirolimo/farmacologia , Serina-Treonina Quinases TOR/antagonistas & inibidores , Serina-Treonina Quinases TOR/metabolismo , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
5.
iScience ; 26(1): 105769, 2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36594018

RESUMO

Multiple genome-wide association studies (GWAS) have identified specific genetic variants in the coiled-coil domain containing 92 (CCDC92) locus that is associated with obesity and type 2 diabetes in humans. However, the biological function of CCDC92 in obesity and insulin resistance remains to be explored. Utilizing wild-type (WT) and Ccdc92 whole-body knockout (KO) mice, we found that Ccdc92 KO reduced obesity and increased insulin sensitivity under high-fat diet (HFD) conditions. Ccdc92 KO inhibited macrophage infiltration and fibrosis in white adipose tissue (WAT), suggesting Ccdc92 ablation protects against adipose tissue dysfunction. Ccdc92 deletion also increased energy expenditure and further attenuated hepatic steatosis in mice on an HFD. Ccdc92 KO significantly inhibited the inflammatory response and suppressed the NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome in WAT. Altogether, we demonstrated the critical role of CCDC92 in metabolism, constituting a potential target for treating obesity and insulin resistance.

6.
Cardiovasc Res ; 119(10): 1981-1996, 2023 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-37392461

RESUMO

AIMS: Systemic inflammation occurs commonly during many human disease settings and increases vascular permeability, leading to organ failure, and lethal outcomes. Lipocalin 10 (Lcn10), a poorly characterized member of the lipocalin family, is remarkably altered in the cardiovascular system of human patients with inflammatory conditions. Nonetheless, whether Lcn10 regulates inflammation-induced endothelial permeability remains unknown. METHODS AND RESULTS: Systemic inflammation models were induced using mice by injection of endotoxin lipopolysaccharide (LPS) or caecal ligation and puncture (CLP) surgery. We observed that the expression of Lcn10 was dynamically altered only in endothelial cells (ECs), but not in either fibroblasts or cardiomyocytes isolated from mouse hearts following the LPS challenge or CLP surgery. Using in vitro gain- and loss-of-function approaches and an in vivo global knockout mouse model, we discovered that Lcn10 negatively regulated endothelial permeability upon inflammatory stimuli. Loss of Lcn10 augmented vascular leakage, leading to severe organ damage and higher mortality following LPS challenge, compared to wild-type controls. By contrast, overexpression of Lcn10 in ECs displayed opposite effects. A mechanistic analysis revealed that both endogenous and exogenous elevation of Lcn10 in ECs could activate slingshot homologue 1 (Ssh1)-Cofilin signalling cascade, a key axis known to control actin filament dynamics. Accordingly, a reduced formation of stress fibre and increased generation of cortical actin band were exhibited in Lcn10-ECs, when compared to controls upon endotoxin insults. Furthermore, we identified that Lcn10 interacted with LDL receptor-related protein 2 (LRP2) in ECs, which acted as an upstream factor of the Ssh1-Confilin signalling. Finally, injection of recombinant Lcn10 protein into endotoxic mice showed therapeutic effects against inflammation-induced vascular leakage. CONCLUSION: This study identifies Lcn10 as a novel regulator of EC function and illustrates a new link in the Lcn10-LRP2-Ssh1 axis to controlling endothelial barrier integrity. Our findings may provide novel strategies for the treatment of inflammation-related diseases.


Assuntos
Células Endoteliais , Lipopolissacarídeos , Humanos , Animais , Camundongos , Células Endoteliais/metabolismo , Lipopolissacarídeos/farmacologia , Lipopolissacarídeos/metabolismo , Transdução de Sinais , Inflamação/prevenção & controle , Inflamação/metabolismo , Camundongos Knockout , Receptores de LDL/metabolismo
7.
Cell Mol Gastroenterol Hepatol ; 13(3): 717-737, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34781022

RESUMO

BACKGROUND & AIMS: We previously showed that histamine suppressed inflammation-associated colonic tumorigenesis through histamine type 2 receptor (H2R) signaling in mice. This study aimed to precisely elucidate the downstream effects of H2R activation in innate immune cells. METHODS: Analyses using online databases of single-cell RNA sequencing of intestinal epithelial cells in mice and RNA sequencing of mouse immune cells were performed to determine the relative abundances of 4 histamine receptors among different cell types. Mouse neutrophils, which expressed greater amounts of H2R, were collected from the peritoneum of wild-type and H2R-deficient mice, of which low-density and high-density neutrophils were extracted by centrifugation and were subjected to RNA sequencing. The effects of H2R activation on neutrophil differentiation and its functions in colitis and inflammation-associated colon tumors were investigated in a mouse model of dextran sulfate sodium-induced colitis. RESULTS: Data analysis of RNA sequencing and quantitative reverse-transcription polymerase chain reaction showed that Hrh2 is highly expressed in neutrophils, but barely detectable in intestinal epithelial cells. In mice, the absence of H2R activation promoted infiltration of neutrophils into both sites of inflammation and colonic tumors. H2R-deficient high-density neutrophils yielded proinflammatory features via nuclear factor-κB and mitogen-activated protein kinase signaling pathways, and suppressed T-cell proliferation. On the other hand, low-density neutrophils, which totally lack H2R activation, showed an immature phenotype compared with wild-type low-density neutrophils, with enhanced MYC pathway signaling and reduced expression of the maturation marker Toll-like receptor 4. CONCLUSIONS: Blocking H2R signaling enhanced proinflammatory responses of mature neutrophils and suppressed neutrophil maturation, leading to accelerated progression of inflammation-associated colonic tumorigenesis.


Assuntos
Mucosa Intestinal , Neutrófilos , Animais , Carcinogênese/patologia , Homeostase , Inflamação/patologia , Mucosa Intestinal/metabolismo , Camundongos , Neutrófilos/metabolismo
8.
Biomedicines ; 9(2)2021 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-33546224

RESUMO

Angiogenesis, a process of new blood vessel formation from the pre-existing vascular bed, is a critical event in various physiological and pathological settings. Over the last few years, the role of endothelial cell (EC) metabolism in angiogenesis has received considerable attention. Accumulating studies suggest that ECs rely on aerobic glycolysis, rather than the oxidative phosphorylation pathway, to produce ATP during angiogenesis. To date, numerous critical regulators of glucose metabolism, fatty acid oxidation, and glutamine metabolism have been identified to modulate the EC angiogenic switch and pathological angiogenesis. The unique glycolytic feature of ECs is critical for cell proliferation, migration, and responses to environmental changes. In this review, we provide an overview of recent EC glucose metabolism studies, particularly glycolysis, in quiescent and angiogenic ECs. We also summarize and discuss potential therapeutic strategies that take advantage of EC metabolism. The elucidation of metabolic regulation and the precise underlying mechanisms could facilitate drug development targeting EC metabolism to treat angiogenesis-related diseases.

9.
J Am Heart Assoc ; 10(24): e023601, 2021 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-34796717

RESUMO

Aortic aneurysm, including thoracic aortic aneurysm and abdominal aortic aneurysm, is the second most prevalent aortic disease following atherosclerosis, representing the ninth-leading cause of death globally. Open surgery and endovascular procedures are the major treatments for aortic aneurysm. Typically, thoracic aortic aneurysm has a more robust genetic background than abdominal aortic aneurysm. Abdominal aortic aneurysm shares many features with thoracic aortic aneurysm, including loss of vascular smooth muscle cells (VSMCs), extracellular matrix degradation and inflammation. Although there are limitations to perfectly recapitulating all features of human aortic aneurysm, experimental models provide valuable tools to understand the molecular mechanisms and test novel therapies before human clinical trials. Among the cell types involved in aortic aneurysm development, VSMC dysfunction correlates with loss of aortic wall structural integrity. Here, we discuss the role of VSMCs in aortic aneurysm development. The loss of VSMCs, VSMC phenotypic switching, secretion of inflammatory cytokines, increased matrix metalloproteinase activity, elevated reactive oxygen species, defective autophagy, and increased senescence contribute to aortic aneurysm development. Further studies on aortic aneurysm pathogenesis and elucidation of the underlying signaling pathways are necessary to identify more novel targets for treating this prevalent and clinical impactful disease.


Assuntos
Aneurisma Aórtico , Músculo Liso Vascular , Miócitos de Músculo Liso , Aneurisma Aórtico/genética , Aneurisma Aórtico/patologia , Aneurisma da Aorta Abdominal/genética , Aneurisma da Aorta Abdominal/patologia , Aneurisma da Aorta Torácica/genética , Aneurisma da Aorta Torácica/patologia , Humanos , Músculo Liso Vascular/patologia , Miócitos de Músculo Liso/patologia
10.
Oncotarget ; 12(18): 1787-1801, 2021 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-34504651

RESUMO

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive pediatric leukemia with a worse prognosis than most frequent B-cell ALL due to a high incidence of treatment failures and relapse. Our previous work showed that loss of the pioneer factor KLF4 in a NOTCH1-induced T-ALL mouse model accelerated the development of leukemia through expansion of leukemia-initiating cells and activation of the MAP2K7 pathway. Similarly, epigenetic silencing of the KLF4 gene in children with T-ALL was associated with MAP2K7 activation. Here, we showed the small molecule 5Z-7-oxozeaenol (5Z7O) induces dose-dependent cytotoxicity in a panel of T-ALL cell lines mainly through inhibition of the MAP2K7-JNK pathway, which further validates MAP2K7 as a therapeutic target. Mechanistically, 5Z7O-mediated apoptosis was caused by the downregulation of regulators of the G2/M checkpoint and the inhibition of survival pathways. The anti-leukemic capacity of 5Z7O was evaluated using leukemic cells from two mouse models of T-ALL and patient-derived xenograft cells generated using lymphoblasts from pediatric T-ALL patients. Finally, a combination of 5Z7O with dexamethasone, a drug used in frontline therapy, showed synergistic induction of cytotoxicity. In sum, we report here that MAP2K7 inhibition thwarts survival mechanisms in T-ALL cells and warrants future pre-clinical studies for high-risk and relapsed patients.

11.
Cancer Res ; 75(1): 40-50, 2015 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-25388284

RESUMO

Vascular tumors are endothelial cell neoplasms whose mechanisms of tumorigenesis are poorly understood. Moreover, current therapies, particularly those for malignant lesions, have little beneficial effect on clinical outcomes. In this study, we show that endothelial activation of the Akt1 kinase is sufficient to drive de novo tumor formation. Mechanistic investigations uncovered opposing functions for different Akt isoforms in this regulation, where Akt1 promotes and Akt3 inhibits vascular tumor growth. Akt3 exerted negative effects on tumor endothelial cell growth and migration by inhibiting activation of the translation regulatory kinase S6-Kinase (S6K) through modulation of Rictor expression. S6K in turn acted through a negative feedback loop to restrain Akt3 expression. Conversely, S6K signaling was increased in vascular tumor cells where Akt3 was silenced, and the growth of these tumor cells was inhibited by a novel S6K inhibitor. Overall, our findings offer a preclinical proof of concept for the therapeutic utility of treating vascular tumors, such as angiosarcomas, with S6K inhibitors.


Assuntos
Proteínas Proto-Oncogênicas c-akt/metabolismo , Neoplasias Vasculares/enzimologia , Neoplasias Vasculares/patologia , Animais , Linhagem Celular Tumoral , Proliferação de Células/fisiologia , Feminino , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Nus , Fosforilação
12.
Nat Med ; 18(10): 1560-9, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22983395

RESUMO

The class II α-isoform of phosphatidylinositol 3-kinase (PI3K-C2α) is localized in endosomes, the trans-Golgi network and clathrin-coated vesicles; however, its functional role is not well understood. Global or endothelial-cell-specific deficiency of PI3K-C2α resulted in embryonic lethality caused by defects in sprouting angiogenesis and vascular maturation. PI3K-C2α knockdown in endothelial cells resulted in a decrease in the number of PI3-phosphate-enriched endosomes, impaired endosomal trafficking, defective delivery of VE-cadherin to endothelial cell junctions and defective junction assembly. PI3K-C2α knockdown also impaired endothelial cell signaling, including vascular endothelial growth factor receptor internalization and endosomal RhoA activation. Together, the effects of PI3K-C2α knockdown led to defective endothelial cell migration, proliferation, tube formation and barrier integrity. Endothelial PI3K-C2α deficiency in vivo suppressed postischemic and tumor angiogenesis and diminished vascular barrier function with a greatly augmented susceptibility to anaphylaxis and a higher incidence of dissecting aortic aneurysm formation in response to angiotensin II infusion. Thus, PI3K-C2α has a crucial role in vascular formation and barrier integrity and represents a new therapeutic target for vascular disease.


Assuntos
Barreira Alveolocapilar/metabolismo , Neovascularização Fisiológica , Fosfatidilinositol 3-Quinases/metabolismo , Angiotensina II/metabolismo , Animais , Antígenos CD/genética , Antígenos CD/metabolismo , Caderinas/genética , Caderinas/metabolismo , Adesão Celular , Movimento Celular/genética , Proliferação de Células , Células Cultivadas , Vesículas Revestidas por Clatrina/metabolismo , Células Endoteliais da Veia Umbilical Humana , Humanos , Camundongos , Camundongos Knockout , Fosfatidilinositol 3-Quinases/deficiência , Fosfatidilinositol 3-Quinases/genética , Interferência de RNA , RNA Interferente Pequeno , Receptores de Fatores de Crescimento do Endotélio Vascular/metabolismo , Transdução de Sinais/genética , Proteína rhoA de Ligação ao GTP/genética , Proteína rhoA de Ligação ao GTP/metabolismo , Rede trans-Golgi/metabolismo
13.
Am J Cancer Res ; 1(4): 460-81, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21984966

RESUMO

Sphingosine-1-phosphate (S1P) is a plasma lipid mediator with multiple roles in mammalian development, physiology and pathophysiology. It is constitutively produced mostly by erythrocytes by the action of sphingosine kinase 1 (SphK1), resulting in high (∼0.5 micromolar) steady-state plasma S1P content and steep S1P concentration gradient imposed between plasma/lymph/tissue interstitial fluid. S1P is also locally produced by activated platelets and tumor cells, in the latter case SphK1 is a downstream target of activated Ras mutant and hypoxia, and is frequently upregulated especially in advanced stages of tumors. Most if not all of the S1P actions in vertebrates are mediated through evolutionarily conserved G protein-coupled S1P receptor family. Ubiquitously expressed mammalian subtypes S1PR1, S1PR2 and S1PR3 mediate pleiotropic actions of S1P in diverse cell types, through coupling to distinctive repertoire of heterotrimeric G proteins. S1PR1 and S1PR3 mediate directed cell migration toward S1P through coupling to G(i) and activating Rac, a Rho family small G protein essential for cell migration. Indeed, S1PR1 expressed in lymphocytes directs their egress from lymph nodes into lymph and recirculation, serving as the target for downregulation by the immunosuppressant FTY720 (fingolimod). S1PR1 in endothelial cells plays an essential role in vascular maturation in embryonic stage, and mediates angiogenic and vascular protective roles of S1P which include eNOS activation and maintenance of barrier integrity. It is likely that S1PR1 and SphK1 expressed in host endothelial cells and tumor cells act in concert in a paracrine loop to contribute to tumor angiogenesis, tumor invasion and progression. In sharp contrast, S1PR2 mediates S1P inhibition of Rac at the site downstream of G(12/13)-mediated Rho activation, thus identified as the first G protein-coupled receptor that negatively regulates Rac and cell migration. S1PR2 could also mediate inhibition of Akt and cell proliferation/survival signaling via Rho-ROCK-PTEN pathway. S1PR2 expressed in tumor cells mediates inhibition of cell migration and invasion in vitro and metastasis in vivo. Moreover, S1PR2 expressed in host endothelial cells and tumor-infiltrating myeloid cells in concert mediates potent inhibition of tumor angiogenesis and tumor growth in vivo, with inhibition of VEGF expression and MMP9 activity. These recent findings provide further basis for S1P receptor subtype-specific, novel therapeutic tactics for individualized treatment of patients with cancer.

14.
World J Biol Chem ; 1(10): 298-306, 2010 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-21537463

RESUMO

Sphingosine-1-phosphate (S1P) is a blood-borne lipid mediator with pleiotropic biological activities. S1P acts via the specific cell surface G-protein-coupled receptors, S1P(1-5). S1P(1) and S1P(2) were originally identified from vascular endothelial cells (ECs) and smooth muscle cells, respectively. Emerging evidence shows that S1P plays crucial roles in the regulation of vascular functions, including vascular formation, barrier protection and vascular tone via S1P(1), S1P(2) and S1P(3). In particular, S1P regulates vascular formation through multiple mechanisms; S1P exerts both positive and negative effects on angiogenesis and vascular maturation. The positive and negative effects of S1P are mediated by S1P(1) and S1P(2), respectively. These effects of S1P(1) and S1P(2) are probably mediated by the S1P receptors expressed in multiple cell types including ECs and bone-marrow-derived cells. The receptor-subtype-specific, distinct effects of S1P favor the development of novel therapeutic tactics for antitumor angiogenesis in cancer and therapeutic angiogenesis in ischemic diseases.

15.
Cancer Res ; 70(2): 772-81, 2010 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-20068174

RESUMO

Sphingosine-1-phosphate (S1P) has been implicated in tumor angiogenesis by acting through the G(i)-coupled chemotactic receptor S1P(1). Here, we report that the distinct receptor S1P(2) is responsible for mediating the G(12/13)/Rho-dependent inhibitory effects of S1P on Akt, Rac, and cell migration, thereby negatively regulating tumor angiogenesis and tumor growth. By using S1P(2)(LacZ/+) mice, we found that S1P(2) was expressed in both tumor and normal blood vessels in many organs, in both endothelial cells (EC) and vascular smooth muscle cells, as well as in tumor-associated, CD11b-positive bone marrow-derived cells (BMDC). Lewis lung carcinoma or B16 melanoma cells implanted in S1P(2)-deficient (S1P(2)(-/-)) mice displayed accelerated tumor growth and angiogenesis with enhanced association of vascular smooth muscle cells and pericytes. S1P(2)(-/-) ECs exhibited enhanced Rac activity, Akt phosphorylation, cell migration, proliferation, and tube formation in vitro. Coinjection of S1P(2)(-/-) ECs and tumor cells into wild-type mice also produced a relative enhancement of tumor growth and angiogenesis in vivo. S1P(2)(-/-) mice were also more efficient at recruiting CD11b-positive BMDCs into tumors compared with wild-type siblings. Bone marrow chimera experiments revealed that S1P(2) acted in BMDCs to promote tumor growth and angiogenesis. Our results indicate that, in contrast to endothelial S1P(1), which stimulates tumor angiogenesis, S1P(2) on ECs and BMDCs mediates a potent inhibition of tumor angiogenesis, suggesting a novel therapeutic tactic for anticancer treatment.


Assuntos
Carcinoma Pulmonar de Lewis/irrigação sanguínea , Melanoma Experimental/irrigação sanguínea , Receptores de Lisoesfingolipídeo/biossíntese , Animais , Células da Medula Óssea/metabolismo , Células da Medula Óssea/patologia , Transplante de Medula Óssea , Carcinoma Pulmonar de Lewis/metabolismo , Carcinoma Pulmonar de Lewis/patologia , Processos de Crescimento Celular/fisiologia , Feminino , Melanoma Experimental/metabolismo , Melanoma Experimental/patologia , Camundongos , Camundongos Transgênicos , Neovascularização Patológica/genética , Neovascularização Patológica/metabolismo , Neovascularização Patológica/patologia , Receptores de Lisoesfingolipídeo/deficiência , Receptores de Lisoesfingolipídeo/genética
16.
Eur J Pharmacol ; 634(1-3): 121-31, 2010 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-20206620

RESUMO

Therapeutic angiogenesis is a promising strategy for treating ischemia. The lysophospholipid mediator sphingosine-1-phosphate (S1P) acts on vascular endothelial cells to stimulate migration and tube formation, and plays the critical role in developmental angiogenesis. We developed poly(lactic-co-glycolic-acid) (PLGA)-based S1P-containing microparticles (PLGA-S1P), which are biodegradable and continuously release S1P, and studied the effects of PLGA-S1P on neovascularization in murine ischemic hindlimbs. Intramuscular injections of PLGA-S1P stimulated blood flow in C57BL/6 mice dose-dependently, with repeated administrations at a 3-day interval, rather than a single bolus or 6-day interval, over 28 days conferring the optimal stimulating effect. In Balb/c mice that exhibit limb necrosis and dysfunction due to retarded blood flow recovery, injections of PLGA-S1P stimulated blood flow with alleviation of limb necrosis and dysfunction. PLGA-S1P alone did not induce edema in ischemic limbs, and rather blocked vascular endothelial growth factor-induced edema. PLGA-S1P not only increased the microvessel densities in ischemic muscle, but promoted coverage of vessels with smooth muscle cells and pericytes, thus stabilizing vessels. PLGA-S1P stimulated Akt and ERK with increased phosphorylation of endothelial nitric oxide synthase in ischemic muscle. The effects of the nitric oxide synthase inhibitor, Nomega-nitro-L-arginine methylester, showed that PLGA-S1P-induced blood flow stimulation was partially dependent on nitric oxide. Injections of PLGA-S1P also increased the expression of angiogenic factors and the recruitment of CD45-, CD11b- and Gr-1-positive myeloid cells, which are implicated in post-ischemic angiogenesis, into ischemic muscle. These results indicate that PLGA-based, sustained local delivery of S1P is a potentially useful therapeutic modality for stimulating post-ischemic angiogenesis.


Assuntos
MAP Quinases Reguladas por Sinal Extracelular/fisiologia , Isquemia/tratamento farmacológico , Isquemia/fisiopatologia , Ácido Láctico/administração & dosagem , Lisofosfolipídeos/administração & dosagem , Neovascularização Fisiológica/efeitos dos fármacos , Óxido Nítrico Sintase Tipo III/fisiologia , Ácido Poliglicólico/administração & dosagem , Proteínas Proto-Oncogênicas c-akt/fisiologia , Esfingosina/análogos & derivados , Animais , Preparações de Ação Retardada/administração & dosagem , Modelos Animais de Doenças , Membro Posterior/irrigação sanguínea , Membro Posterior/efeitos dos fármacos , Isquemia/enzimologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Microesferas , Neovascularização Patológica/tratamento farmacológico , Neovascularização Patológica/enzimologia , Neovascularização Patológica/fisiopatologia , Neovascularização Fisiológica/fisiologia , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Distribuição Aleatória , Fluxo Sanguíneo Regional/efeitos dos fármacos , Fluxo Sanguíneo Regional/fisiologia , Esfingosina/administração & dosagem
17.
J Clin Invest ; 120(11): 3979-95, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20978351

RESUMO

Sphingosine-1-phosphate (S1P) is a biologically active sphingolipid that has pleiotropic effects in a variety of cell types including ECs, SMCs, and macrophages, all of which are central to the development of atherosclerosis. It may therefore exert stimulatory and inhibitory effects on atherosclerosis. Here, we investigated the role of the S1P receptor S1PR2 in atherosclerosis by analyzing S1pr2-/- mice with an Apoe-/- background. S1PR2 was expressed in macrophages, ECs, and SMCs in atherosclerotic aortas. In S1pr2-/-Apoe-/- mice fed a high-cholesterol diet for 4 months, the area of the atherosclerotic plaque was markedly decreased, with reduced macrophage density, increased SMC density, increased eNOS phosphorylation, and downregulation of proinflammatory cytokines compared with S1pr2+/+Apoe-/- mice. Bone marrow chimera experiments indicated a major role for macrophage S1PR2 in atherogenesis. S1pr2-/-Apoe-/- macrophages showed diminished Rho/Rho kinase/NF-κB (ROCK/NF-κB) activity. Consequently, they also displayed reduced cytokine expression, reduced oxidized LDL uptake, and stimulated cholesterol efflux associated with decreased scavenger receptor expression and increased cholesterol efflux transporter expression. S1pr2-/-Apoe-/- ECs also showed reduced ROCK and NF-κB activities, with decreased MCP-1 expression and elevated eNOS phosphorylation. Pharmacologic S1PR2 blockade in S1pr2+/+Apoe-/- mice diminished the atherosclerotic plaque area in aortas and modified LDL accumulation in macrophages. We conclude therefore that S1PR2 plays a critical role in atherogenesis and may serve as a novel therapeutic target for atherosclerosis.


Assuntos
Apolipoproteínas E/deficiência , Aterosclerose/imunologia , Aterosclerose/patologia , Macrófagos/imunologia , Receptores de Lisoesfingolipídeo/metabolismo , Animais , Apolipoproteínas E/genética , Aterosclerose/genética , Becaplermina , Células Cultivadas , Feminino , Lisofosfolipídeos/metabolismo , Macrófagos/citologia , Macrófagos/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Miócitos de Músculo Liso/citologia , Miócitos de Músculo Liso/fisiologia , NF-kappa B/genética , NF-kappa B/metabolismo , Placa Aterosclerótica/patologia , Fator de Crescimento Derivado de Plaquetas/metabolismo , Proteínas Proto-Oncogênicas c-sis , Receptores de Lisoesfingolipídeo/antagonistas & inibidores , Receptores de Lisoesfingolipídeo/genética , Esfingosina/análogos & derivados , Esfingosina/metabolismo , Receptores de Esfingosina-1-Fosfato , Quinases Associadas a rho/genética , Quinases Associadas a rho/metabolismo
18.
Cardiovasc Res ; 85(3): 484-93, 2010 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-19755413

RESUMO

AIMS: Sphingosine kinase 1 (SPHK1), its product sphingosine-1-phosphate (S1P), and S1P receptor subtypes have been suggested to play protective roles for cardiomyocytes in animal models of ischaemic preconditioning and cardiac ischaemia/reperfusion injury. To get more insight into roles for SPHK1 in vivo, we have generated SPHK1-transgenic (TG) mice and analysed the cardiac phenotype. METHODS AND RESULTS: SPHK1-TG mice overexpressed SPHK1 in diverse tissues, with a nearly 20-fold increase in enzymatic activity. The TG mice grew normally with normal blood chemistry, cell counts, heart rate, and blood pressure. Unexpectedly, TG mice with high but not low expression levels of SPHK1 developed progressive myocardial degeneration and fibrosis, with upregulation of embryonic genes, elevated RhoA and Rac1 activity, stimulation of Smad3 phosphorylation, and increased levels of oxidative stress markers. Treatment of juvenile TG mice with pitavastatin, an established inhibitor of the Rho family G proteins, or deletion of S1P3, a major myocardial S1P receptor subtype that couples to Rho GTPases and transactivates Smad signalling, both inhibited cardiac fibrosis with concomitant inhibition of SPHK1-dependent Smad-3 phosphorylation. In addition, the anti-oxidant N-2-mercaptopropyonylglycine, which reduces reactive oxygen species (ROS), also inhibited cardiac fibrosis. In in vivo ischaemia/reperfusion injury, the size of myocardial infarct was 30% decreased in SPHK1-TG mice compared with wild-type mice. CONCLUSION: These results suggest that chronic activation of SPHK1-S1P signalling results in both pathological cardiac remodelling through ROS mediated by S1P3 and favourable cardioprotective effects.


Assuntos
Miocárdio/patologia , Fosfotransferases (Aceptor do Grupo Álcool)/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Receptores de Lisoesfingolipídeo/fisiologia , Animais , Fibrose , Imunofluorescência , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Miocárdio/metabolismo , Neuropeptídeos/biossíntese , Quinolinas/farmacologia , Receptores de Lisoesfingolipídeo/análise , Receptores de Esfingosina-1-Fosfato , Proteínas rac de Ligação ao GTP/biossíntese , Proteínas rac1 de Ligação ao GTP , Proteínas rho de Ligação ao GTP/biossíntese , Proteína rhoA de Ligação ao GTP
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