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1.
Mol Pharmacol ; 101(5): 322-333, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35273080

RESUMEN

Ceramide is a bioactive sphingolipid that mediates ionizing radiation- and chemotherapy-induced apoptosis. Neocarzinostatin (NCS) is a genotoxic anti-cancer drug that induces apoptosis in response to DNA double-strand breaks (DSBs) through ataxia telangiectasia mutated (ATM) activation. However, the involvement of ceramide in NCS-evoked nuclear events such as DSB-activated ATM has not been clarified. Here, we found that nuclear ceramide increased by NCS-mediated apoptosis through the enhanced assembly of ATM and the meiotic recombination 11/double-strand break repair/Nijmengen breakage syndrome 1 (MRN) complex proteins in human lymphoblastoid L-39 cells. NCS induced an increase of ceramide production through activation of neutral sphingomyelinase (nSMase) and suppression of sphingomyelin synthase (SMS) upstream of DSB-mediated ATM activation. In ATM-deficient lymphoblastoid AT-59 cells compared with L-39 cells, NCS treatment showed a decrease of apoptosis even though ceramide increase and DSBs were observed. Expression of wild-type ATM, but not the kinase-dead mutant ATM, in AT-59 cells increased NCS-induced apoptosis despite similar ceramide accumulation. Interestingly, NCS increased ceramide content in the nucleus through nSMase activation and SMS suppression and promoted colocalization of ceramide with phosphorylated ATM and foci of MRN complex. Inhibition of ceramide generation by the overexpression of SMS suppressed NCS-induced apoptosis through the inhibition of ATM activation and assembly of the MRN complex. In addition, inhibition of ceramide increased by the nSMase inhibitor GW4869 prevented NCS-mediated activation of the ATM. Therefore, our findings suggest the involvement of the nuclear ceramide with ATM activation in NCS-mediated apoptosis. SIGNIFICANCE STATEMENT: This study demonstrates that regulation of ceramide with neutral sphingomyelinase and sphingomyelin synthase in the nucleus in double-strand break-mimetic agent neocarzinostatin (NCS)-induced apoptosis. This study also showed that ceramide increase in the nucleus plays a role in NCS-induced apoptosis through activation of the ataxia telangiectasia mutated/meiotic recombination 11/double-strand break repair/Nijmengen breakage syndrome 1 complex in human lymphoblastoid cells.


Asunto(s)
Ataxia Telangiectasia , Cinostatina , Apoptosis/genética , Ataxia Telangiectasia/genética , Proteínas de la Ataxia Telangiectasia Mutada/genética , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Proteínas de Ciclo Celular/metabolismo , Ceramidas/farmacología , Reparación del ADN , Proteínas de Unión al ADN/metabolismo , Humanos , Proteínas Serina-Treonina Quinasas , Esfingomielina Fosfodiesterasa/genética , Esfingomielina Fosfodiesterasa/metabolismo , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/metabolismo , Cinostatina/farmacología
2.
Mol Med ; 28(1): 143, 2022 11 29.
Artículo en Inglés | MEDLINE | ID: mdl-36447136

RESUMEN

BACKGROUND: Mesenchymal stem cells (MSCs) are multipotent stromal cells and could exert hepatoprotective effects against acute liver injury, steatohepatitis, and fibrogenesis. Here, we evaluated the effects of human adipose derived stem cells (hADSCs) to attenuate experimentally induced hepatic fibrosis and early cirrhosis in rats. METHODS: Hepatic fibrosis was induced by intraperitoneal injections of CCl4 (0.1 ml/100 g body weight) twice a week for 8 weeks. hADSCs were isolated and cultured on polyethylene discs coated with hydroxyapatite and 2 cm diameter disc was surgically implanted on the right lateral lobe of the liver. Discs implanted without hADSCs served as control. The animals were injected again with CCl4 once a week for another 8 weeks. All the animals were sacrificed at the end of 16th week. RESULTS: Serial administrations of CCl4 resulted in well developed fibrosis and early cirrhosis at 8th week which maintained until the 16th week. Animals treated with hADSC discs depicted over 50% decrease of collagen with significant increase in serum albumin and total protein levels. Immunohistochemical staining for TGF-ß1, α-smooth muscle actin, and collagen type I and type III demonstrated marked decrease compared to the animals without hADSC treatment. CONCLUSIONS: Treatment with hADSCs improved liver functions, markedly reduced hepatic fibrosis and early cirrhosis. Various pleiotropic and paracrine factors secreted from the hADSCs seem to serve as reparative functions in the attenuation of liver cirrhosis. The data demonstrated that treatment with hADSCs can be successfully used as a potent therapeutic method to prevent progression of hepatic fibrosis and related adverse events.


Asunto(s)
Adipocitos , Tejido Adiposo , Humanos , Ratas , Animales , Células Madre , Cirrosis Hepática/inducido químicamente , Cirrosis Hepática/terapia
3.
FASEB J ; 34(3): 3838-3854, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-31970839

RESUMEN

The tumor microenvironment (TME) formation involving host cells and cancer cells through cell adhesion molecules (CAMs) is essential for the multiple steps of cancer metastasis and growth. Sphingomyelin synthase 2 (SMS2) is involved in inflammatory diseases such as obesity and diabetes mellitus by regulation of the SM/ceramide balance. However, the involvement of SMS2 in TME formation and metastasis is largely unknown. Here, we report that SMS2-deficient (SMS2-KO) mice show suppressed the EL4 cell infiltration to liver and prolonged survival time. ICAM-1 was identified as a candidate for the inhibition of TME formation in immortalized mouse embryonic fibroblasts (tMEFs) from mRNA array analysis for CAMs. Reduced SM/ceramide balance in SMS2-KO tMEFs suppressed the attachment of EL4 cells through transcriptional reduction of ICAM-1 by the inhibition of NF-κB activation. TNF-α-induced NF-κB activation and subsequent induction of ICAM-1 were suppressed in SMS2-KO tMEFs but restored by SMS2 re-introduction. In the EL4 cell infiltration mouse model, EL4 injection increased ICAM-1 expression in WT liver but not in SMS2-KO mouse liver. Therefore, inhibition of SMS2 may be a therapeutic target to suppress the infiltration of malignant lymphoma.


Asunto(s)
Molécula 1 de Adhesión Intercelular/metabolismo , Transferasas (Grupos de Otros Fosfatos Sustitutos)/metabolismo , Animales , Western Blotting , Línea Celular Tumoral , Cromatografía Liquida , Modelos Animales de Enfermedad , Citometría de Flujo , Glucosiltransferasas/metabolismo , Inmunohistoquímica , Molécula 1 de Adhesión Intercelular/genética , Hígado/efectos de los fármacos , Hígado/metabolismo , Ratones , Ratones Noqueados , Ratones Mutantes , ARN Mensajero/genética , ARN Mensajero/metabolismo , Espectrometría de Masas en Tándem , Transferasas (Grupos de Otros Fosfatos Sustitutos)/genética , Factor de Necrosis Tumoral alfa/farmacología
4.
Mol Med ; 25(1): 56, 2019 12 17.
Artículo en Inglés | MEDLINE | ID: mdl-31847800

RESUMEN

BACKGROUND: There are two isoforms of sphingomyelin synthase (SMS): SMS1 and SMS2. SMS1 is located in the Golgi apparatus only while SMS2 is located in both the plasma membrane and the Golgi apparatus. SMS1 and SMS2 act similarly to generate sphingomyelin (SM). We have undertaken the experiments reported here on SMS and osteoblast differentiation in order to better understand the role SMS plays in skeletal development. METHODS: We analyzed the phenotype of a conditional knockout mouse, which was generated by mating a Sp7 promoter-driven Cre-expressing mouse with an SMS1-floxed SMS2-deficient mouse (Sp7-Cre;SMS1f/f;SMS2-/- mouse). RESULTS: When we compared Sp7-Cre;SMS1f/f;SMS2-/- mice with C57BL/6, SMS2-deficient mice (SMS1f/f;SMS2-/-) and SP7-Cre positive control mice (Sp7-Cre, Sp7-Cre;SMS1+/+;SMS2+/- and Sp7-Cre;SMS1+/+;SMS2-/-), we found that although cartilage formation is normal, Sp7-Cre;SMS1f/f;SMS2-/- mice showed reduced trabecular and cortical bone mass, had lower bone mineral density, and had a slower mineral apposition rate than control mice. Next, we have used a tamoxifen-inducible knockout system in vitro to show that SMS1 plays an important role in osteoblast differentiation. We cultured osteoblasts derived from ERT2-Cre;SMS1f/f SMS2-/- mice. We observed impaired differentiation of these cells in response to Smad1/5/8 and p38 that were induced by bone morphogenic protein 2 (BMP2). However, Erk1/2 phosphorylation was unaffected by inactivation of SMS1. CONCLUSIONS: These findings provide the first genetic evidence that SMS1 plays a role in bone development by regulating osteoblast development in cooperation with BMP2 signaling. Thus, SMS1 acts as an endogenous signaling component necessary for bone formation.


Asunto(s)
Diferenciación Celular/genética , Osteoblastos/fisiología , Osteogénesis/genética , Transferasas (Grupos de Otros Fosfatos Sustitutos) , Animales , Huesos/citología , Huesos/metabolismo , Masculino , Ratones , Ratones Noqueados , Transferasas (Grupos de Otros Fosfatos Sustitutos)/deficiencia , Transferasas (Grupos de Otros Fosfatos Sustitutos)/genética , Transferasas (Grupos de Otros Fosfatos Sustitutos)/metabolismo
5.
FASEB J ; 31(9): 3816-3830, 2017 09.
Artículo en Inglés | MEDLINE | ID: mdl-28522594

RESUMEN

Sphingomyelin synthase 2 (SMS2) is the synthetic enzyme of sphingomyelin (SM), which regulates membrane fluidity and microdomain structure. SMS2 plays a role in LPS-induced lung injury and inflammation; however, its role in inflammation-mediated tumorigenesis is unclear. We investigated the effect of SMS2 deficiency on dextran sodium sulfate (DSS)-induced murine colitis and found inhibition of DSS-induced inflammation in SMS2-deficient (SMS2-/-) mice. DSS treatment induced a significant increase in ceramide levels, with a decrease of SM levels in SMS2-/- colon tissue, and demonstrated attenuation of the elevation of both inflammation-related gene expression and proinflammatory cytokines and chemokines, leukocyte infiltration, and MAPK and signal transducer and activator of transcription 3 activation. After undergoing transplantation of wild-type bone marrow, SMS2-/- mice also exhibited inhibition of DSS-induced inflammation in the colon, which suggested that SMS2 deficiency in bone marrow-derived immune cells was not involved in the inhibition of colitis. Finally, in an azoxymethane/DSS-induced cancer model, SMS2 deficiency significantly decreased tumor incidence in the colon. Our results demonstrate that SMS2 deficiency inhibits DSS-induced colitis and subsequent colitis-associated colon cancer via inhibition of colon epithelial cell-mediated inflammation; therefore, inhibition of SMS2 may be a potential therapeutic target for human colitis and colorectal cancer.-Ohnishi, T., Hashizume, C., Taniguchi, M., Furumoto, H., Han, J., Gao, R., Kinami, S., Kosaka, T., Okazaki, T. Sphingomyelin synthase 2 deficiency inhibits the induction of murine colitis-associated colon cancer.


Asunto(s)
Colitis/complicaciones , Neoplasias del Colon/etiología , Regulación Enzimológica de la Expresión Génica/fisiología , Regulación Neoplásica de la Expresión Génica/fisiología , Transferasas (Grupos de Otros Fosfatos Sustitutos)/metabolismo , Animales , Proliferación Celular , Ceramidas/genética , Ceramidas/metabolismo , Colitis/enzimología , Neoplasias del Colon/enzimología , Inflamación/metabolismo , Lipopolisacáridos , Ratones , Ratones Noqueados , Transducción de Señal , Transferasas (Grupos de Otros Fosfatos Sustitutos)/deficiencia , Transferasas (Grupos de Otros Fosfatos Sustitutos)/genética
6.
Medicines (Basel) ; 9(4)2022 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-35447873

RESUMEN

We report a novel missense mutation, p.Ile424Ser, in the PKD2 gene of an autosomal dominant polycystic kidney disease (ADPKD) patient with multiple liver cysts. A 57-year-old woman presented to our university hospital with abdominal fullness, decreasing appetite, and dyspnea for three months. A percutaneous drainage of hepatic cysts was performed with no significant symptomatic relief. A computed tomography (CT) scan revealed a hepatic cyst in the lateral portion of the liver with appreciable compression of the stomach. Prior to this admission, the patient had undergone three drainage procedures with serial CT-based follow-up of the cysts over the past 37 years. With a presumptive diagnosis of extrarenal manifestation of ADPKD, we performed both a hepatic cystectomy and a hepatectomy. Because the patient reported a family history of hepatic cysts, we conducted a postoperative genetic analysis. A novel missense mutation, p.Ile424Ser, was detected in the PKD2 gene. Mutations in either the PKD1 or PKD2 genes account for most cases of ADPKD. To the extent of our knowledge, this point mutation has not been reported in the general population. Our in-silico analysis suggests a hereditary likely pathogenic mutation.

7.
J Biol Chem ; 285(14): 10841-9, 2010 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-20133940

RESUMEN

Gain or loss of whole chromosomes is often observed in cancer cells and is thought to be due to aberrant chromosome segregation during mitosis. Proper chromosome segregation depends on a faithful interaction between spindle microtubules and kinetochores. Several components of the nuclear pore complex/nucleoporins play critical roles in orchestrating the rapid remodeling events that occur during mitosis. Our recent studies revealed that the nucleoporin, Rae1, plays critical roles in maintaining spindle bipolarity. Here, we show association of another nucleoporin, termed Tpr (translocated promoter region), with the molecular motors dynein and dynactin, which both orchestrate with the spindle checkpoints Mad1 and Mad2 during cell division. Overexpression of Tpr enhanced multinucleated cell formation. RNA interference-mediated knockdown of Tpr caused a severe lagging chromosome phenotype and disrupted spindle checkpoint proteins expression and localization. Next, we performed a series of rescue and dominant negative experiments to confirm that Tpr orchestrates proper chromosome segregation through interaction with dynein light chain. Our data indicate that Tpr functions as a spatial and temporal regulator of spindle checkpoints, ensuring the efficient recruitment of checkpoint proteins to the molecular motor dynein to promote proper anaphase formation.


Asunto(s)
Anafase/fisiología , Segregación Cromosómica , Dineínas/metabolismo , Metafase/fisiología , Proteínas de Complejo Poro Nuclear/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Animales , Western Blotting , Proteínas de Unión al Calcio/genética , Proteínas de Unión al Calcio/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Dineínas Citoplasmáticas/genética , Dineínas Citoplasmáticas/metabolismo , Dineínas/antagonistas & inhibidores , Dineínas/genética , Células HeLa , Humanos , Técnicas para Inmunoenzimas , Cinetocoros , Proteínas Mad2 , Ratones , Células 3T3 NIH , Proteínas de Complejo Poro Nuclear/antagonistas & inhibidores , Proteínas de Complejo Poro Nuclear/genética , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas Proto-Oncogénicas/antagonistas & inhibidores , Proteínas Proto-Oncogénicas/genética , Interferencia de ARN , ARN Mensajero/genética , ARN Mensajero/metabolismo , ARN Interferente Pequeño/farmacología , Proteínas Recombinantes/genética , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/metabolismo , Proteínas Represoras/genética , Proteínas Represoras/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Huso Acromático
9.
Blood Adv ; 5(20): 4265-4277, 2021 10 26.
Artículo en Inglés | MEDLINE | ID: mdl-34478523

RESUMEN

Sphingomyelin synthase 1 (SMS1) contributes to the generation of membrane sphingomyelin (SM) and affects SM-mediated physiological functions. Here, we describe the hematologic phenotypes, such as reduced circulating platelets and dysfunctional hemostasis, in SMS1-deficient (SMS1-KO) mice. SMS1-KO mice display pathologic manifestations related to idiopathic thrombocytopenia (ITP), including relatively high amounts of peripheral blood reticulated platelets, enhanced megakaryopoiesis in the bone marrow and spleen, and splenomegaly. Deficiency of SMS1, but not SMS2, prevented SM production and enhanced phosphatidylserine (PS) externalization on the plasma membranes of platelets and megakaryocytes. Consequently, SMS1-KO platelets were excessively cleared by macrophages in the spleen. Multimer formation in the plasma membrane of TMEM16F, a known calcium (Ca2+)-activated nonselective ion channel and Ca2+-dependent PS scramblase, was enhanced; the result was PS externalization to outer leaflets through increased Ca2+ influx in immortalized mouse embryonic fibroblasts established from SMS1-KO mice (SMS1-KO tMEFs), as seen with SMS1-KO platelets. Thus, SMS1 deficiency changed the TMEM16F distribution on the membrane microdomain, regulating Ca2+ influx-dependent PS exposure. SMS1-KO tMEFs in which TMEM16F was knocked out by using the CRISPR/Cas9 system lacked both the Ca2+ influx and excess PS exposure seen in SMS1-KO tMEFs. Therefore, SM depletion on platelet membrane microdomains due to SMS1 deficiency enhanced PS externalization via a Ca2+ influx through TMEM16F activation, leading to elevated platelet clearance and causing hemostasis dysfunction through thrombocytopenia. Our current findings show that the SM-rich microdomain generated by SMS1 is a potent regulator of thrombocytopenia through TMEM16F, suggesting that its dysfunction may be a novel additional mechanism of ITP.


Asunto(s)
Fosfatidilserinas , Trombocitopenia , Animales , Anoctaminas , Fibroblastos , Ratones , Trombocitopenia/genética , Transferasas (Grupos de Otros Fosfatos Sustitutos)/genética
10.
Mol Cancer ; 9: 119, 2010 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-20497554

RESUMEN

Nuclear pore complexes are massive multiprotein channels responsible for traffic between the nucleus and cytoplasm, and are composed of approximately 30 proteins, termed nucleoporins (Nup). Our recent studies indicated that the nucleoporins Rae1 and Tpr play critical roles in maintaining the spindle bipolarity during cell division. In the present study, we found that another nucleoporin, Nup88, was localized on the spindles together with Nup214 during mitosis. Nup88 expression is linked to the progression of carcinogenesis, Nup88 has been proposed as a tumor marker. Overexpression of Nup88 enhanced multinucleated cell formation. RNAi-mediated knockdown of Nup88 disrupted Nup214 expression and localization and caused multipolar spindle phenotypes. Our data indicate that proper expression of Nup88 is critical for preventing aneuploidy formation and tumorigenesis.


Asunto(s)
Biomarcadores de Tumor/análisis , Mitosis/fisiología , Neoplasias/genética , Proteínas de Complejo Poro Nuclear/metabolismo , Huso Acromático/metabolismo , Aneuploidia , Transformación Celular Neoplásica/genética , Electroforesis en Gel de Poliacrilamida , Técnica del Anticuerpo Fluorescente , Inestabilidad Genómica , Células HeLa , Humanos , Inmunoprecipitación , Proteínas de Complejo Poro Nuclear/genética , ARN Interferente Pequeño , Huso Acromático/genética , Transfección
11.
Microbes Infect ; 9(4): 490-7, 2007 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-17347016

RESUMEN

Vpr, an accessory gene product of human immunodeficiency virus type 1 (HIV-1), affects both viral and cellular proliferation by mediating long terminal repeat activation, cell cycle arrest at the G2 phase, and apoptosis. We previously found that Vpr plays a novel role as a regulator of pre-mRNA splicing both in vivo and in vitro. However, the cellular target of Vpr, as well as the mechanism of cellular pre-mRNA splicing inhibition by Vpr, is unknown. Here, we show clearly that Vpr inhibits the splicing of cellular pre-mRNA, such as beta-globin pre-mRNA and immunoglobulin (Ig) M pre-mRNA and that the third alpha-helical domain and arginine-rich region are important its ability to inhibit splicing. Additionally, using mutants with specific substitutions in two domains of Vpr, we demonstrated that the interaction between Vpr and SAP145, an essential splicing factor, was indispensable for splicing inhibition. Finally, co-immunoprecipitation and in vitro competitive binding assays indicated that Vpr associates with SAP145 and interferes with SAP145-SAP49 complex formation. Thus, these results suggest that cellular expression of Vpr may block spliceosome assembly by interfering with the function of the SAP145-SAP49 complex in host cells.


Asunto(s)
Productos del Gen vpr/metabolismo , Precursores del ARN/genética , Proteínas de Unión al ARN/metabolismo , Empalmosomas/metabolismo , Secuencia de Aminoácidos , beta-Globulinas/genética , Unión Competitiva , Productos del Gen vpr/genética , Células HeLa , Humanos , Inmunoglobulina M/genética , Inmunoprecipitación , Datos de Secuencia Molecular , Unión Proteica , Empalme del ARN , Factores de Empalme de ARN , ARN Mensajero/genética , ARN Mensajero/metabolismo , Proteínas de Unión al ARN/genética , Empalmosomas/genética
12.
Behav Brain Res ; 319: 25-30, 2017 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-27840247

RESUMEN

Sphingomyelin synthases (SMSs) are enzymes converting ceramide to sphingomyelin. The behavioral phenotype attributed to their disruption has not been well described. We examined learning ability and hippocampal synaptic plasticity in mice deficient in SMS2 (SMS2 KO). In context-dependent fear learning and novel object recognition test, no difference in learning ability was detected in SMS2 KO and wild-type (WT) mice. By contrast, achievement of the Morris water maze (MWM) test was deteriorated in SMS2 KO mice. In the hippocampal CA1, while the basic synaptic transmission was normal, both short- and long-term synaptic plasticity was moderately suppressed. We interpret that the MWM test taking place in wet environment may represent learning paradigm under more stressful condition than those performed in dry conditions, and that the learning ability of SMS2 KO mice failed to manifest itself fully in stressful situations. In agreement, forced swimming induced depression-like behavior more easily in SMS2 KO mice. Mass spectrometry suggested a slightly altered species distribution of ceramide in the hippocampus of SMS2 KO mice. These findings support the proposal that altered synthesis of ceramide, which is the substrate of SMS2 and therefore expected to be modified in SMS2 KO mice, is associated with depression-like tendency in animal models and depressive disorder in humans.


Asunto(s)
Cognición/fisiología , Depresión/genética , Discapacidades para el Aprendizaje/genética , Transferasas (Grupos de Otros Fosfatos Sustitutos)/deficiencia , Análisis de Varianza , Animales , Fenómenos Biofísicos/genética , Ceramidas/metabolismo , Depresión/fisiopatología , Modelos Animales de Enfermedad , Estimulación Eléctrica , Conducta Exploratoria/fisiología , Hipocampo/fisiología , Técnicas In Vitro , Potenciación a Largo Plazo/genética , Potenciación a Largo Plazo/fisiología , Aprendizaje por Laberinto , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Plasticidad Neuronal/genética , Reconocimiento en Psicología/fisiología , Natación/psicología , Transferasas (Grupos de Otros Fosfatos Sustitutos)/genética
14.
Microbes Infect ; 7(9-10): 1150-60, 2005 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-15908254

RESUMEN

Vpr, one of the accessory gene products of human immunodeficiency virus type 1 (HIV-1), affects aspects of both viral and cellular proliferation, being involved in long terminal repeat (LTR) activation, arrest of the cell cycle at the G2 phase, and apoptosis. We have discovered a novel role for Vpr as a regulator of the splicing of pre-mRNA both in vivo and in vitro. We found, by RT-PCR and RNase protection analysis, that Vpr caused the accumulation of incompletely spliced forms of alpha-globin 2 and beta-globin pre-mRNAs in cells that had been transiently transfected with a Vpr expression vector. We postulated that this novel effect of Vpr might occur via a pathway that is distinct from arrest of the cell cycle at G2. By analyzing splicing reactions in vitro, we showed that Vpr inhibited the splicing of beta-globin pre-mRNA in vitro. The splicing of intron 1 of alpha-globin 2 pre-mRNA was modestly inhibited by Vpr but the splicing of intron 2 was unaffected. Interestingly, an experimental infection system which utilizes high-titered HIV-1/vesticular stomatitis virus G protein showed that Vpr expressed from an HIV-1 provirus was sufficient to accumulate endogenous alpha-globin 2 pre-mRNA. Thus, it is likely that Vpr contributes to selective inhibition of the splicing of cellular pre-mRNA.


Asunto(s)
Productos del Gen vpr/fisiología , VIH-1/fisiología , Precursores del ARN/metabolismo , Empalme del ARN , Western Blotting , Línea Celular , Globinas/análisis , Globinas/genética , Humanos , Intrones/genética , Ensayos de Protección de Nucleasas , ARN Mensajero/análisis , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Productos del Gen vpr del Virus de la Inmunodeficiencia Humana
15.
Cell Cycle ; 14(9): 1447-58, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25789545

RESUMEN

Spindle poles are defined by centrosomes; therefore, an abnormal number or defective structural organization of centrosomes can lead to loss of spindle bipolarity and genetic integrity. Previously, we showed that Tpr (translocated promoter region), a component of the nuclear pore complex (NPC), interacts with Mad1 and dynein to promote proper chromosome segregation during mitosis. Tpr also associates with p53 to induce autophagy. Here, we report that Tpr depletion induces mitotic catastrophe and enhances the rate of tetraploidy and polyploidy. Mechanistically, Tpr interacts, via its central domain, with Aurora A but not Aurora B kinase. In Tpr-depleted cells, the expression levels, centrosomal localization and phosphorylation of Aurora A were all reduced. Surprisingly, an Aurora A inhibitor, Alisertib (MLN8237), also disrupted centrosomal localization of Tpr and induced mitotic catastrophe and cell death in a time- and dose-dependent manner. Strikingly, over-expression of Aurora A disrupted Tpr centrosomal localization only in cells with supernumerary centrosomes but not in bipolar cells. Our results highlight the mutual regulation between Tpr and Aurora A and further confirm the importance of nucleoporin function in spindle pole organization, bipolar spindle assembly, and mitosis; functions that are beyond the conventional nucleocytoplasmic transport and NPC structural roles of nucleoporins. Furthermore, the central coiled-coil domain of Tpr binds to and sequesters extra Aurora A to safeguard bipolarity. This Tpr domain merits further investigation for its ability to inhibit Aurora kinase and as a potential therapeutic agent in cancer treatment.


Asunto(s)
Aurora Quinasa A/metabolismo , Centrosoma/enzimología , Mitosis , Proteínas de Complejo Poro Nuclear/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Antineoplásicos/farmacología , Aurora Quinasa A/antagonistas & inhibidores , Aurora Quinasa A/genética , Puntos de Control del Ciclo Celular , Centrosoma/efectos de los fármacos , Segregación Cromosómica , Células HeLa , Humanos , Mitosis/efectos de los fármacos , Proteínas de Complejo Poro Nuclear/genética , Unión Proteica , Dominios y Motivos de Interacción de Proteínas , Mapeo de Interacción de Proteínas , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas/genética , Interferencia de ARN , Transducción de Señal , Tetraploidía , Transfección
16.
Cell Cycle ; 12(24): 3804-16, 2013 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-24107630

RESUMEN

Centrosomes are comprised of 2 orthogonally arranged centrioles surrounded by the pericentriolar material (PCM), which serves as the main microtubule organizing center of the animal cell. More importantly, centrosomes also control spindle polarity and orientation during mitosis. Recently, we and other investigators discovered that several nucleoporins play critical roles during cell division. Here, we show that nucleoporin Nup62 plays a novel role in centrosome integrity. Knockdown of Nup62 induced mitotic arrest in G 2/M phases and mitotic cell death. Depletion of Nup62 using RNA interference results in defective centrosome segregation and centriole maturation during the G 2 phase. Moreover, Nup62 depletion in human cells leads to the appearance of multinucleated cells and induces the formation of multipolar centrosomes, centriole synthesis defects, dramatic spindle orientation defects, and centrosome component rearrangements that impair cell bi-polarity. Our results also point to a potential role of Nup62 in targeting gamma-tubulin and SAS-6 to the centrioles.


Asunto(s)
Centrosoma/fisiología , Proteínas de Complejo Poro Nuclear/metabolismo , Animales , Línea Celular , Centriolos/fisiología , Puntos de Control de la Fase G2 del Ciclo Celular , Homeostasis , Humanos , Puntos de Control de la Fase M del Ciclo Celular , Ratones , Mitosis , Huso Acromático/fisiología , Tubulina (Proteína)/metabolismo
17.
J Nutr Sci Vitaminol (Tokyo) ; 58(6): 423-30, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-23419401

RESUMEN

Resistant maltodextrin (RMD) is a soluble dietary fiber ingredient whose physiological functions are well recognized in Foods for Specified Health Use (FOSHU) for maintaining healthy intestinal regularity, blood glucose levels, and serum lipids. However, its efficacy on combined health risks--metabolic syndrome--was not studied yet. In this study the efficacy of RMD on humans with metabolic syndrome was investigated. A randomized double-blind placebo-controlled parallel-group trial was conducted. Thirty subjects with metabolic syndrome were randomly allocated into 2 groups and took either tea containing 9 g of RMD (treatment group) or placebo tea at three mealtimes daily for 12 wk. Blood was collected and body fat was scanned periodically. In the RMD treatment group, waist circumference, visceral fat area, fasting blood glucose, HOMA-R and serum triacylglycerol (TG) were significantly decreased compared to baseline, and significant time-by-treatment interaction was observed for waist circumference, visceral fat area, HOMA-R and serum TG (p=0.044, p=0.012, p=0.032, and p=0.049, respectively). The change ratio of visceral fat area showed negative statistical correlation with the baseline value (p=0.033), suggesting that efficacy of RMD was emphasized in the subjects having a larger visceral fat area. After the 12-wk RMD treatment, the total number of metabolic syndrome risk factors decreased to 20 from 32 with 2 subjects having no risks, while that of the placebo group decreased to 25 from 32. These findings suggest that continuous ingestion of RMD may improve the risk factors of metabolic syndrome by reducing visceral fat and improving glucose and lipid metabolism.


Asunto(s)
Síndrome Metabólico/tratamiento farmacológico , Polisacáridos/administración & dosificación , Anciano , Pueblo Asiatico , Glucemia/análisis , Glucemia/efectos de los fármacos , Composición Corporal/efectos de los fármacos , Colesterol/sangre , Método Doble Ciego , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Insulina/sangre , Grasa Intraabdominal/efectos de los fármacos , Grasa Intraabdominal/metabolismo , Leptina/sangre , Masculino , Persona de Mediana Edad , Obesidad/tratamiento farmacológico , Factores de Riesgo , Triglicéridos/sangre
18.
Cell Cycle ; 10(3): 425-33, 2011 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-21270521

RESUMEN

Many human cancers have irregular chromosome content, a condition known as aneuploidy. Several nuclear pore proteins (nucleoporins/Nups) that mediate transport of RNA or macromolecules into and out of the nucleus have been implicated in mitosis. These nucleoporins are involved in molecular networks that function in a variety of mitotic processes, including chromosome condensation, sister chromatid cohesion, kinetochore assembly and spindle formation. An alteration in the concentration of Nups inside cells often causes aneuploidy. In this review, we discuss this sprouting area and the possible functions of Nups during mitosis.


Asunto(s)
Ciclo Celular , Proteínas de Complejo Poro Nuclear/fisiología , Transporte Activo de Núcleo Celular , Humanos , Mitosis , Modelos Biológicos , Poro Nuclear/química , Poro Nuclear/metabolismo , Poro Nuclear/fisiología , Proteínas de Complejo Poro Nuclear/química
19.
Cell Cycle ; 10(9): 1456-67, 2011 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-21467841

RESUMEN

Chromosomal translocations involving chimeric fusions of the nucleoporin NUP98 protein have often been described in acute myelogenous leukemia (AML). All the fusion proteins have an identical NUP98 N terminus, which contains the GLEBS motif for interaction with the mRNA export factor RAE1 and FG repeats that associate with the transcription factors HDAC1 and p300. It is virtually unknown whether these interaction partners affect leukemogenesis. We previously showed that RAE1 depletion caused aneuploidy, which enhanced tumorigenesis. We speculated that RAE1 may also be directly involved in NUP98 fusion-mediated leukemogenesis. We show here that RNA interference (RNAi)-mediated knockdown of NUP98 caused severe chromosome segregation defects and disrupted RAE1 but not HDAC1 expression and localization. Next, we performed rescue experiments to confirm that the RAE1-NUP98 complex orchestrates proper chromosome segregation. Interestingly, we found diverse behaviors of NUP98 and the leukemogenic fusion protein NUP98-HOXA9 throughout the cell cycle. Strikingly, in NUP98-HOXA9-transfected cells, RAE1 protein were reduced and mis-localized. Our cellular interpretations were further confirmed by NUP98-HOXA9 transgenic mice and the NUP98-HOXA9 AML patient. These data suggest that RAE1 orchestrates NUP98-mediated leukemogenesis and raise the possibility that targeting this negative feedback loop may provide a new strategy for the therapy of aggressive leukemias.


Asunto(s)
Regulación Leucémica de la Expresión Génica , Proteínas de Homeodominio/fisiología , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patología , Proteínas Asociadas a Matriz Nuclear/fisiología , Proteínas de Complejo Poro Nuclear/fisiología , Proteínas de Transporte Nucleocitoplasmático/fisiología , Adulto , Animales , Segregación Cromosómica/genética , Femenino , Regulación Leucémica de la Expresión Génica/fisiología , Células HEK293 , Células HeLa , Proteínas de Homeodominio/genética , Humanos , Células K562 , Leucemia Mieloide Aguda/etiología , Ratones , Ratones Transgénicos , Persona de Mediana Edad , Proteínas Asociadas a Matriz Nuclear/genética , Proteínas de Complejo Poro Nuclear/genética , Proteínas de Transporte Nucleocitoplasmático/genética , Estructura Terciaria de Proteína/genética , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo
20.
J Agric Food Chem ; 57(17): 7659-65, 2009 Sep 09.
Artículo en Inglés | MEDLINE | ID: mdl-19663481

RESUMEN

Total nondigestible carbohydrate (NDC) in foods was determined by combining, not modifications, AOAC Official Methods 991.43, 2001.03, and 2002.02. Total NDC included insoluble dietary fiber (IDF) + high-molecular-weight soluble dietary fiber (HMWSDF), nondigestible oligosaccharides (NDO) not precipitated in ethanol solution, and resistant starch (RS). Eight sources of NDC (cellulose, wheat bran, gum arabic, resistant maltodextrin, polydextrose, fructooligosaccharide, galactooligosaccharides, and RS) were incorporated in different combinations into standard formula bread samples. All of the NDC sources and bread samples were analyzed for their (1) IDF + HMWSDF content with corrections for residual RS amount using AOAC Official Method 991.43, (2) NDO by liquid chromatography (LC) in AOAC Official Method 2001.03, and (3) RS by AOAC Official Method 2002.02. The correlation coefficient (R(2)) comparing calculated amounts versus measured amounts of total NDC in 11 bread samples was 0.92. Analysis of commercial food samples was also well matched with the DF + NDO value on their nutritional label. Consequently, we confirmed a single measurement of LC can determine all NDO in foods, and total NDC in foods can be determined by unifying existing AOAC Official Methods.


Asunto(s)
Carbohidratos/análisis , Cromatografía Liquida , Fibras de la Dieta/análisis , Análisis de los Alimentos/métodos , Pan/análisis , Precipitación Química , Filtración , Glucano 1,4-alfa-Glucosidasa/metabolismo , Oligosacáridos/análisis , Péptido Hidrolasas/metabolismo , alfa-Amilasas/metabolismo
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