RESUMEN
RNA methylation of N6-methyladenosine (m6A) is emerging as a fundamental regulator of every aspect of RNA biology. RNA methylation directly impacts protein production to achieve quick modulation of dynamic biological processes. However, whether RNA methylation regulates mitochondrial function is not known, especially in neuronal cells which require a high energy supply and quick reactive responses. Here we show that m6A RNA methylation regulates mitochondrial function through promoting nuclear-encoded mitochondrial complex subunit RNA translation. Conditional genetic knockout of m6A RNA methyltransferase Mettl14 (Methyltransferase like 14) by Nestin-Cre together with metabolomic analysis reveals that Mettl14 knockout-induced m6A depletion significantly downregulates metabolites related to energy metabolism. Furthermore, transcriptome-wide RNA methylation profiling of wild type and Mettl14 knockout mouse brains by m6A-Seq shows enrichment of methylation on mitochondria-related RNA. Importantly, loss of m6A leads to a significant reduction in mitochondrial respiratory capacity and membrane potential. These functional defects are paralleled by the reduced expression of mitochondrial electron transport chain complexes, as well as decreased mitochondrial super-complex assembly and activity. Mechanistically, m6A depletion decreases the translational efficiency of methylated RNA encoding mitochondrial complex subunits through reducing their association with polysomes, while not affecting RNA stability. Together, these findings reveal a novel role for RNA methylation in regulating mitochondrial function. Given that mitochondrial dysfunction and RNA methylation have been increasingly implicate in neurodegenerative disorders, our findings not only provide insights into fundamental mechanisms regulating mitochondrial function, but also open up new avenues for understanding the pathogenesis of neurological diseases.
Asunto(s)
Adenosina , Metiltransferasas , Ratones Noqueados , Mitocondrias , Animales , Mitocondrias/metabolismo , Mitocondrias/genética , Ratones , Metilación , Metiltransferasas/genética , Metiltransferasas/metabolismo , Adenosina/análogos & derivados , Adenosina/metabolismo , Adenosina/genética , ARN/genética , ARN/metabolismo , Humanos , Biosíntesis de Proteínas , Metabolismo Energético/genética , Neuronas/metabolismo , Metilación de ARNRESUMEN
Oxidative stress response is a fundamental biological process mediated by conserved mechanisms. The identities and functions of some key regulators remain unknown. Here, we report a novel role of C. elegans casein kinase 1 gamma CSNK-1 (also known as CK1γ or CSNK1G) in regulating oxidative stress response and ROS levels. csnk-1 interacted with the bli-3/tsp-15/doxa-1 NADPH dual oxidase genes via genetic nonallelic noncomplementation to affect C. elegans survival in oxidative stress. The genetic interaction was supported by specific biochemical interactions between DOXA-1 and CSNK-1 and potentially between their human orthologs DUOXA2 and CSNK1G2. Consistently, CSNK-1 was required for normal ROS levels in C. elegans. CSNK1G2 and DUOXA2 each can promote ROS levels in human cells, effects that were suppressed by a small molecule casein kinase 1 inhibitor. We also detected genetic interactions between csnk-1 and skn-1 Nrf2 in oxidative stress response. Together, we propose that CSNK-1 CSNK1G defines a novel conserved regulatory mechanism for ROS homeostasis.
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Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Animales , Humanos , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Oxidasas Duales/farmacología , NADP , Especies Reactivas de Oxígeno , Quinasa de la Caseína I/genética , Estrés Oxidativo/genética , NADPH Oxidasas , Tetraspaninas/genéticaRESUMEN
Spinal muscular atrophy (SMA), the top genetic cause of infant mortality, is characterized by motor neuron degeneration. Mechanisms underlying SMA pathogenesis remain largely unknown. Here, we report that the activity of cyclin-dependent kinase 5 (Cdk5) and the conversion of its activating subunit p35 to the more potent activator p25 are significantly up-regulated in mouse models and human induced pluripotent stem cell (iPSC) models of SMA. The increase of Cdk5 activity occurs before the onset of SMA phenotypes, suggesting that it may be an initiator of the disease. Importantly, aberrant Cdk5 activation causes mitochondrial defects and motor neuron degeneration, as the genetic knockout of p35 in an SMA mouse model rescues mitochondrial transport and fragmentation defects, and alleviates SMA phenotypes including motor neuron hyperexcitability, loss of excitatory synapses, neuromuscular junction denervation, and motor neuron degeneration. Inhibition of the Cdk5 signaling pathway reduces the degeneration of motor neurons derived from SMA mice and human SMA iPSCs. Altogether, our studies reveal a critical role for the aberrant activation of Cdk5 in SMA pathogenesis and suggest a potential target for therapeutic intervention.
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Células Madre Pluripotentes Inducidas , Atrofia Muscular Espinal , Animales , Humanos , Ratones , Quinasa 5 Dependiente de la Ciclina/genética , Quinasa 5 Dependiente de la Ciclina/metabolismo , Modelos Animales de Enfermedad , Células Madre Pluripotentes Inducidas/metabolismo , Neuronas Motoras/metabolismo , Atrofia Muscular Espinal/metabolismo , Degeneración Nerviosa/patología , Proteína 1 para la Supervivencia de la Neurona Motora/genética , Proteína 1 para la Supervivencia de la Neurona Motora/metabolismoRESUMEN
Epigenetics play an essential role in the occurrence and improvement of many diseases. Evidence shows that epigenetic modifications are crucial to the regulation of gene expression. DNA methylation is closely linked to embryonic development in mammalian. In recent years, epigenetic drugs have shown unexpected therapeutic effects on neurological diseases, leading to the study of the epigenetic mechanism in neurodegenerative diseases. Unlike genetics, epigenetics modify the genome without changing the DNA sequence. Research shows that epigenetics is involved in all aspects of neurodegenerative diseases. The study of epigenetic will provide valuable insights into the molecular mechanism of neurodegenerative diseases, which may lead to new treatments and diagnoses. This article reviews the role of epigenetic modifications neurodegenerative diseases with dyskinesia, and discusses the therapeutic potential of epigenetic drugs in neurodegenerative diseases.
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Discinesias , Enfermedades Neurodegenerativas , Animales , Metilación de ADN/genética , Discinesias/genética , Epigénesis Genética , Humanos , Mamíferos , Enfermedades Neurodegenerativas/genéticaRESUMEN
Di-(2-ethylhexyl) phthalate (DEHP) is a representative endocrine-disrupting chemical (EDC) that has reproductive, developmental, neurological and immune toxicity in humans and rodents, of which damage to the reproductive system is the most serious. However, exposure to DEHP at different stages of life may produce different symptoms. Studies on this substance are also controversial. This review describes the reproductive effects of DEHP in males and females at different life stages, including infancy, childhood and adulthood.
RESUMEN
Exposure to manganese (Mn) can cause male reproductive damage and lead to abnormal secretion of sex hormones. Gonadotropin-releasing hormone (GnRH) plays an important role in the neuromodulation of vertebrate reproduction. Astrocytes can indirectly regulate the secretion of GnRH by binding paracrine prostaglandin E2 (PGE2) specifically to the EP1 and EP2 receptors on GnRH neurons. Prior studies assessed the abnormal secretion of GnRH caused by Mn exposure, but the specific mechanism has not been reported in detail. This study investigated the effects of Mn exposure on the reproductive system of male mice to clarify the role of PGE2 in the abnormal secretion of GnRH in the hypothalamus caused by exposure to Mn. Our data demonstrate that antagonizing the EP1 and EP2 receptors of PGE2 can restore abnormal levels of GnRH caused by Mn exposure. Mn exposure causes reduced sperm count and sperm shape deformities. These findings suggest that EP1 and EP2, the receptors of PGE2, may be the key to abnormal GnRH secretion caused by Mn exposure. Antagonizing the PGE2 receptors may reduce reproductive damage caused by Mn exposure.
Asunto(s)
Hormona Liberadora de Gonadotropina/metabolismo , Hipotálamo/efectos de los fármacos , Manganeso/toxicidad , Subtipo EP1 de Receptores de Prostaglandina E/metabolismo , Subtipo EP2 de Receptores de Prostaglandina E/metabolismo , Reproducción/efectos de los fármacos , Animales , Hipotálamo/metabolismo , Masculino , Manganeso/metabolismo , Ratones , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Subtipo EP1 de Receptores de Prostaglandina E/antagonistas & inhibidores , Subtipo EP2 de Receptores de Prostaglandina E/antagonistas & inhibidoresRESUMEN
Gamma-aminobutyric acid (GABA) plays a critical role in regulation of gonadotropin-releasing hormone (GnRH) through GABAA receptor (GABAAR). Nitric oxide (NO) production has correlation with GABA and regulates GnRH secretion. This study was performed to examine the mechanisms by which manganese (Mn) accelerate puberty onset involves GABAAR/NO pathway in the preoptic area-anterior hypothalamus (POA-AH) in immature female rats. First, female rats received daily dose of MnCl2 0 (saline), 2.5, 5 and 10â¯mg/kg b.w by oral gavage during postnatal day (PND) 21-32. Animals administered with 10â¯mg/kg MnCl2 exhibited earlier puberty onset age and advanced ovary and uterus development than these in saline-treatment group. Furthermore, we found that decrease of GABAAR result in elevated production of nitric oxide synthase1 (NOS1), NO and GnRH in the POA-AH. Second, we recorded the neuronal spikes alternation after perfusion with GABAAR inhibitor bicuculline (BIC), GABAAR agonist isoguvacine (isog), and MnCl2 from the POA-AH in acute brain slices of PND21 rats. Spontaneous firing revealed a powerful GABAAR-mediated action on immature POA-AH and confirm that MnCl2 has a significant effect on GABAAR. Third, we revealed that decrease in NOS1 and NO production by treatment with isog-alone or isog+MnCl2 contribute to the decrease of GnRH in the POA-AH and a delayed puberty onset age compared to treatment with MnCl2-alone. Together, these results suggested that excessive exposure to MnCl2 stimulates NO production through decreased GABAAR in the POA-AH to advance puberty onset in immature female rats.
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Envejecimiento/efectos de los fármacos , Cloruros/toxicidad , Disruptores Endocrinos/toxicidad , Óxido Nítrico/metabolismo , Área Preóptica/efectos de los fármacos , Receptores de GABA-A/metabolismo , Maduración Sexual/efectos de los fármacos , Envejecimiento/metabolismo , Animales , Femenino , Hormona Liberadora de Gonadotropina/metabolismo , Compuestos de Manganeso , Neuronas/efectos de los fármacos , Ovario/efectos de los fármacos , Ovario/crecimiento & desarrollo , Área Preóptica/crecimiento & desarrollo , Área Preóptica/metabolismo , Ratas , Ratas Sprague-Dawley , Transducción de Señal/efectos de los fármacos , Útero/diagnóstico por imagen , Útero/efectos de los fármacos , DesteteRESUMEN
Methylmercury (MeHg) is a potent neurotoxin,which leads to a wide range of intracellular effects. The molecular mechanismsassociated to MeHg-induced neurotoxicity have not been fully understood.Oxidative stress, as well as synaptic glutamate (Glu) dyshomeostasis have beenidentified as two critical mechanisms during MeHg-mediated cytotoxicity. Here,we developed a rat model of MeHg poisoning to evaluate its neurotoxic effectsby focusing on cellular oxidative stress and synaptic Glu disruption. Inaddition, we investigated the neuroprotective role of alpha-lipoic acid (α-LA), a natural antioxidant, todeeply explore the underlying interaction between them. Fifty-six rats wererandomly divided into four groups: saline control, MeHg treatment (4 or 12µmol/kg MeHg), and α-LApre-treatment (35 µmol/kg α-LA+12µmol/kg MeHg). Rats exposed to 12 µmol/kg MeHg induced neuronal oxidativestress, with ROS accumulation and cellular antioxidant system impairment. Nrf2 andxCT pathways were activated with MeHg treatment. The enzymatic or non-enzymaticof cellular GSH synthesis were also disrupted by MeHg. On the other hand, the abnormalactivities of GS and PAG disturbed the "Glu-Gln cycle", leading to NMDARsover-activation, Ca2+ overload, and the calpain activation, which acceleratedNMDARs degradation. Meanwhile, the high expressions of phospho-p44/42 MAPK,phospho-p38 MAPK, phospho-CREB, and the high levels of caspase 3 and Bax/Bcl-2 finallyindicated the neuronal apoptosis after MeHg exposure. Pre-treatment with α-LA significantly preventedMeHg-induced neurotoxicity. In conclusion, the oxidative stress and synapticGlu dyshomeostasis contributed to MeHg-induced neuronal apoptosis. Alpha-LAattenuated these toxic effects through mechanisms of anti-oxidation andindirect Glu dyshomeostasis prevention.
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Apoptosis/efectos de los fármacos , Corteza Cerebral/efectos de los fármacos , Ácido Glutámico/metabolismo , Compuestos de Metilmercurio/toxicidad , Neuronas/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Receptores de N-Metil-D-Aspartato/metabolismo , Animales , Antioxidantes/metabolismo , Corteza Cerebral/metabolismo , Corteza Cerebral/patología , Masculino , Neuronas/metabolismo , Neuronas/patología , Síndromes de Neurotoxicidad/metabolismo , Síndromes de Neurotoxicidad/patología , Oxidación-Reducción , Ratas , Ratas Wistar , Especies Reactivas de Oxígeno/metabolismo , Ácido Tióctico/farmacologíaRESUMEN
There are limited studies focused on the precise mechanism of gonadotropin-releasing hormone (GnRH) secretion dysfunction after overexposure to manganese (Mn). The objective of the present study was to explore the mechanism of Mn disruption of GnRH synthesis via nuclear factor erythroid-2-related factor-2 (Nrf2)/metabotropic glutamate receptor-5 (mGluR5)/cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE2) signaling pathway in vitro and in vivo. Primary astrocytes were cultured and treated with different doses of Mn, tert-butylhydroquinonet (tBHQ; Nrf2 agonists), 3-[(2-methyl-4-thaizolyl) ethynyl] pyridine (MTEP; mGluR5 inhibitor), and celecoxib (COX-2 inhibitor) to measure the levels of COX-2, mGluR5, Nrf2, and Nrf2 target genes. Mice were randomly divided into 11 groups, of which included the control group, 12.5-, 25-, and 50-mg/kg MnCl2 group, dimethyl sulfoxide (DMSO) group, tBHQ control group, tBHQ pretreatment group, MTEP control group, MTEP pretreatment group, celecoxib control group, and celecoxib pretreatment group. The injection was administered every day for 2 weeks. Then, levels of GnRH, PGE2, COX-2, mGluR5, Nrf2, Nrf2 target genes, and morphological changes in the hypothalamus of mice were measured. Mn reduced protein levels of Nrf2 and mRNA expression of Nrf2 target genes and increased mGluR5, COX-2, PGE2, and GnRH levels. Meanwhile, injury-related histomorphology changes in the hypothalamus of mice were significantly present. In conclusion, excessive exposure to Mn disrupts GnRH secretion through Nrf2/mGluR5/COX-2/PGE2 signaling pathway.
Asunto(s)
Ciclooxigenasa 2/metabolismo , Dinoprostona/metabolismo , Hormona Liberadora de Gonadotropina/metabolismo , Manganeso/farmacología , Factor 2 Relacionado con NF-E2/metabolismo , Receptor del Glutamato Metabotropico 5/metabolismo , Transducción de Señal/efectos de los fármacos , Análisis de Varianza , Animales , Ciclooxigenasa 2/genética , Dinoprostona/genética , Hormona Liberadora de Gonadotropina/genética , Hipotálamo/efectos de los fármacos , Ratones , Factor 2 Relacionado con NF-E2/genética , ARN Mensajero/metabolismo , Distribución Aleatoria , Receptor del Glutamato Metabotropico 5/genética , Transducción de Señal/genéticaRESUMEN
BACKGROUND: Ankylosing spondylitis (AS) is a debilitating autoimmune disease affecting tens of millions of people in the world. The genetics of AS is unclear. Analysis of rare AS pedigrees might facilitate our understanding of AS pathogenesis. METHODS: We used genome-wide linkage analysis and whole-exome sequencing in combination with variant co-segregation verification and haplotype analysis to study an AS pedigree and a sporadic AS patient. RESULTS: We identified a missense variant in the ankyrin repeat and death domain containing 1B gene ANKDD1B from a Han Chinese pedigree with dominantly inherited AS. This variant (p.L87V) co-segregates with all male patients of the pedigree. In females, the penetrance of the symptoms is incomplete with one identified patient out of 5 carriers, consistent with the reduced frequency of AS in females of the general population. We further identified a distinct missense variant affecting a conserved amino acid (p.R102L) of ANKDD1B in a male from 30 sporadic early onset AS patients. Both variants are absent in 500 normal controls. We determined the haplotypes of four major known AS risk loci, including HLA-B*27, 2p15, ERAP1 and IL23R, and found that only HLA-B*27 is strongly associated with patients in our cohort. CONCLUSIONS: Together these results suggest that ANKDD1B variants might be associated with AS and genetic analyses of more AS patients are warranted to verify this association.
Asunto(s)
Predisposición Genética a la Enfermedad/genética , Péptidos y Proteínas de Señalización Intracelular/genética , Mutación Missense/genética , Espondilitis Anquilosante/genética , Adolescente , Adulto , Aminoácidos/genética , Aminopeptidasas/genética , Pueblo Asiatico/genética , Estudios de Casos y Controles , Preescolar , Estudios de Cohortes , Femenino , Ligamiento Genético/genética , Haplotipos/genética , Humanos , Masculino , Antígenos de Histocompatibilidad Menor/genética , Linaje , Receptores de Interleucina/genética , Adulto JovenRESUMEN
Overexposure to manganese (Mn) has been known to induce alpha-synuclein (α-Syn) oligomerization, which is degraded mainly depending on endoplasmic reticulum stress (ER stress) and autophagy pathways. However, little data reported the cross-talk between ER stress and autophagy on Mn-induced α-Syn oligomerization. To explore the relationship between ER stress and autophagy, we used 4-phenylbutyric acid (4-PBA, the ER stress inhibitor), rapamycin (Rap, autophagy activator) and 3-methyladenine (3-MA, autophagy inhibitor) in mice model of manganism. After 4 weeks of treatment with Mn, both ER stress and autophagy were activated. Exposed to Mn also resulted in α-Syn oligomerization and neuronal cell damage in the brain tissue of mice, which could be relieved by 4-PBA pretreatment. Moreover, when the ER stress was inhibited, the activation of autophagy was also inhibited. Rap pretreatment significantly activated autophagy and decreased α-Syn oligomers. However, 3-MA pretreatment inhibited autophagy resulting in increase of α-Syn oligomers, and compensatorily activated PERK signaling pathway. Our results also demonstrated that the inhibition of autophagy by 3-MA aggravated neuronal cell damage. The findings clearly demonstrated that the cross-talking between autophagy and ER stress might play an important role in the α-Syn oligomerization and neurotoxicity by Mn.
Asunto(s)
Autofagia/efectos de los fármacos , Estrés del Retículo Endoplásmico/efectos de los fármacos , Contaminantes Ambientales/toxicidad , Manganeso/toxicidad , alfa-Sinucleína/metabolismo , Adenina/análogos & derivados , Adenina/farmacología , Animales , Apoptosis/efectos de los fármacos , Encéfalo/citología , Encéfalo/efectos de los fármacos , Butilaminas/farmacología , Cloruros/toxicidad , Compuestos de Manganeso , Ratones Endogámicos C57BL , Neuronas/citología , Neuronas/efectos de los fármacos , Fenilbutiratos/farmacología , Polimerizacion , Transducción de Señal , Sirolimus/farmacologíaRESUMEN
Overexposure to manganese (Mn) has been known to disrupt neurotransmitter release in the brain. However, the underlying mechanisms of Mn exposure on neurotransmitter vesicle release are still unclear. The current study investigated whether the protein expression and their interaction of SNARE complex associated proteins were the media between Mn exposure and neurotransmitter vesicle fusion disorders. After the neurons were respectively exposed to Mn (0-200 µM) for 0, 6, 12, 18, 24 h, there were different degrees of cell injury in neurons. According to the results, Mn exposures in subsequent experiments were restricted to concentrations of 100 µM for 0, 6, 12, 18, 24 h. Mn was found to down-regulate the expression of SNAP-25 and up-regulate the expression of VAMP-2 in cultured neurons. Moreover, the interaction of Munc 18 and Syntaxin increased significantly in response to Mn treatment for 18-24h, and the interaction of VAMP-2 and Synaptophysin increased first and then decreased. FM1-43-labeled synaptic vesicles also provided evidence that the treatment with Mn resulted in neurotransmitter vesicle fusion increasing first and then decreasing, which was consistent with the 80 kDa protein levels of SNARE complexes. The findings clearly demonstrated that Mn induced the disorders of neurotransmitter vesicle release via disturbing the protein expression and their interaction of SNARE complex associated proteins. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 705-716, 2017.
Asunto(s)
Manganeso/toxicidad , Fusión de Membrana/efectos de los fármacos , Proteínas SNARE/metabolismo , Vesículas Sinápticas/metabolismo , Animales , Supervivencia Celular , Células Cultivadas , Exocitosis , Proteínas del Tejido Nervioso/metabolismo , Neuronas/metabolismo , Cultivo Primario de Células , Proteínas Qa-SNARE/metabolismo , Ratas Wistar , Transmisión SinápticaRESUMEN
Methylmercury (MeHg), an extremely dangerous environmental pollutant, accumulating preferentially in central nervous system, causes a series of cytotoxic effects. The present study explored the mechanisms which contribute to MeHg-induced neurotoxicity focusing on the oxidative stress in rat cerebral cortex. In addition, the protective effects of alpha-lipoic acid (LA), a potent antioxidant on MeHg-mediated neuronal injury, was also investigated in current study. A MeHg poisoning model was established as 64 rats randomly divided into 4 groups of which saline control group, MeHg-treated groups (4 and 12 µmol kg-1 ), and LA pretreatment (35 µmol kg-1 ) group, respectively. After administration of 12 µmol kg-1 MeHg for 4 weeks, it was found that obvious pathological changes and apoptosis in neuronal cells. Meanwhile, total Hg levels elevated significantly, superoxide dismutase (SOD) and gluthathione peroxidase (GSH-Px) activities were inhibited, and ROS formation elevated, which might be critical to aggravate oxidative stress in cerebral cortex. In addition, NF-E2-related factor 2 (Nrf2) pathways were activated, as heme oxygenase-1 (HO-1) and γ-glutamylcysteine synthetase heavy subunit (γ-GCSh) expressions were up-regulated obviously by MeHg exposure. Moreover, activities of Na+ -K+ -ATPase and Ca2+ -ATPase were inhibited, leading to intracellular calcium (Ca2+ ) overload. LA pre-treatment partially reduced MeHg neurotoxic effects via anti-oxidation pathways. In conclusion, these findings clearly indicated that MeHg aggravated oxidative stress and Ca2+ overload in cerebral cortex. LA possesses the ability to prevent MeHg neurotoxicity through its anti-oxidative properties. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 931-943, 2017.
Asunto(s)
Antioxidantes/metabolismo , Apoptosis/efectos de los fármacos , Corteza Cerebral/efectos de los fármacos , Compuestos de Metilmercurio/toxicidad , Ácido Tióctico/farmacología , Animales , Calcio/metabolismo , ATPasas Transportadoras de Calcio/metabolismo , Células Cultivadas , Corteza Cerebral/citología , Corteza Cerebral/metabolismo , Femenino , Glutatión Peroxidasa/metabolismo , Hemo-Oxigenasa 1/genética , Hemo-Oxigenasa 1/metabolismo , Masculino , Factor 2 Relacionado con NF-E2/genética , Factor 2 Relacionado con NF-E2/metabolismo , Ratas , Ratas Wistar , Especies Reactivas de Oxígeno/metabolismo , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Superóxido Dismutasa/metabolismoRESUMEN
Overexposure to manganese (Mn) has been known to induce nitrosative stress. The dysregulation of autophagy has implicated in nitric oxide (NO) bioactivity alterations. However, the mechanism of Mn-induced autophagic dysregulation is unclear. The protein of Bcl-2 was considered as a key role that could participate to the autophagy signaling regulation. To further explore whether S-nitrosylation of Bcl-2 involved in Mn-induced autophagy dysregulation, we treated human neuroblastoma (SH-SY5Y) cells with Mn and pretreated cells with 1400 W, a selective iNOS inhibitor. After cells were treated with 400 µM Mn for 24 h, there were significant increases in production of NO, inducible NO synthase (iNOS) activity, the mRNA and protein expressions of iNOS. Interestingly, autophagy was activated after cells were treated with Mn for 0-12 h; while the degradation process of autophagy-lysosome pathway was blocked after cells were treated with Mn for 24 h. Moreover, S-nitrosylated JNK and Bcl-2 also increased and phospho-JNK and phospho-Bcl-2 reduced in Mn-treated cells. Then, the affinity between Bcl-2 and Beclin-1 increased significantly in Mn-treated cells. We used the 1400 W to neutralize Mn-induced nitrosative stress. The results showed that S-nitrosylated JNK and Bcl-2 reduced while their phosphorylation were recovered to some extent. The findings revealed that NO-mediated S-nitrosylation of Bcl-2 directly affected the interaction between Beclin-1 and Bcl-2 leading to autophagy inhibition.
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Autofagia/efectos de los fármacos , Cloruros/toxicidad , Óxido Nítrico/metabolismo , Beclina-1/metabolismo , Recuento de Células , Línea Celular Tumoral , Humanos , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Lisosomas/metabolismo , Manganeso , Compuestos de Manganeso , Óxido Nítrico Sintasa de Tipo II/metabolismo , Fosforilación , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
Methylmercury (MeHg) is a highly neurotoxic environmental pollutant that has a high appetency to the central nervous system. The underlying mechanisms of MeHg-induced neurotoxicity have not been elucidated clearly until now. Therefore, to explore the mechanisms contribute to MeHg-induced neurotoxicity, rats were exposed to different dosage of methylmercury chloride (CH3 ClHg) (0, 4, and 12 µmol kg(-1)) for 4 weeks to evaluate the neurotoxic effects of MeHg. In addition, considering the antioxidative properties of tea polyphenols (TP), 1 mmol kg(-1) TP was pretreated to observe the possible protective effects on MeHg-induced neurotoxicity. Then Hg, glutamate (Glu) and glutamine (Gln) levels, glutamine synthetase (GS), phosphate-activated glutaminase (PAG), Na(+)-K(+)-ATPase, and Ca(2+)-ATPase activities, intracellular Ca(2+) level were examined, glutathione (GSH), malondialdehyde (MDA), protein sulfhydryl, carbonyl, 8-hydroxy-2-deoxyguanosine (8-OHdG), and reactive oxygen species (ROS) levels, N-methyl-D-aspartate receptors (NMDARs) mRNA and protein expressions, apoptosis level and morphological changes in the cerebral cortex were also investigated. Study results showed that compared with those in control, exposure to CH3 ClHg resulted in excitotoxicity in a concentration-dependent manner, which was shown by the Glu-Gln cycle disruption and intracellular Ca(2+) homeostasis disturbance. On the other hand, CH3 ClHg exposure resulted in oxidative damages of brain, which were supported by the significant changes on GSH, MDA, sulfhydryl, carbonyl, 8-OHdG, and ROS levels. Moreover, apoptosis rate increased obviously and many morphological changes were found after CH3 ClHg exposure. Furthermore, this research indicated that TP pretreatment significantly mitigated the toxic effects of MeHg. In conclusion, findings from this study indicated that exposure to MeHg could induce excitotoxicity and oxidative damage in cerebral cortex while TP might antagonize the MeHg-induced neurotoxicity.
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Corteza Cerebral/efectos de los fármacos , Compuestos de Metilmercurio/toxicidad , Estrés Oxidativo/efectos de los fármacos , Polifenoles/farmacología , Té/química , 8-Hidroxi-2'-Desoxicoguanosina , Adenosina Trifosfatasas/metabolismo , Animales , Apoptosis/efectos de los fármacos , Calcio/metabolismo , Corteza Cerebral/patología , Desoxiguanosina/análogos & derivados , Desoxiguanosina/metabolismo , Femenino , Glutatión/metabolismo , Masculino , Malondialdehído/metabolismo , Oxidación-Reducción , Ratas , Ratas Wistar , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Centromeres are known to cluster around nucleoli in Drosophila and mammalian cells, but the significance of the nucleoli-centromere interaction remains underexplored. To determine whether the interaction is dynamic under different physiological and pathological conditions, we examined nucleolar structure and centromeres at various differentiation stages using cell culture models and the results showed dynamic changes in nucleolar characteristics and nucleoli-centromere interactions through differentiation and in cancer cells. Embryonic stem cells usually have a single large nucleolus, which is clustered with a high percentage of centromeres. As cells differentiate into intermediate states, the nucleolar number increases and the centromere association decreases. In terminally differentiated cells, including myotubes, neurons, and keratinocytes, the number of nucleoli and their association with centromeres are at the lowest. Cancer cells demonstrate the pattern of nucleoli number and nucleoli-centromere association that is akin to proliferative cell types, suggesting that nucleolar reorganization and changes in nucleoli-centromere interactions may play a role in facilitating malignant transformation. This idea is supported in a case of pediatric rhabdomyosarcoma, in which induced differentiation reduces the nucleolar number and centromere association. These findings suggest active roles of nucleolar structure in centromere function and genome organization critical for cellular function in both normal development and cancer.
Asunto(s)
Nucléolo Celular , Neoplasias , Animales , Nucléolo Celular/metabolismo , Centrómero , Núcleo Celular/metabolismo , Mamíferos , Neoplasias/metabolismoRESUMEN
OBJECTIVE: To investigate the effect of extracts with water and alcohol from Radix Trichosanthis on the cell survival and the expression of hepatitis B surface antigen (HBsAg) and hepatitis B e-antigen (HBeAg) in HepG2.2.15 cell supernatant. METHODS: The cell survival rate of HepG2.2.15 cells was detected by MTT assay. The HBsAg and HBeAg in HepG 2.2.15 cell supernatant were evaluated by enzyme linked immunosorbent assay. RESULTS: The water and alcohol soluble extracts from Radix Trichosanthis significantly inhibited the levels of HBsAg and HBeAg in HepG2.2.15 cells in a time-and-concentration-dependent manner. However, the therapeutic index of extracts with water from Radix Trichosanthis was better than that in the alcohol group. CONCLUSION: The activity of water-soluble extract from Radix Trichosanthis is stronger on anti-hepatitis B virus than that of the alcohol-soluble extract.
Asunto(s)
Antivirales/farmacología , Medicamentos Herbarios Chinos/farmacología , Antígenos de Superficie de la Hepatitis B/biosíntesis , Antígenos e de la Hepatitis B/biosíntesis , Medicamentos Herbarios Chinos/clasificación , Células Hep G2 , Virus de la Hepatitis B/efectos de los fármacos , HumanosRESUMEN
Manganese (Mn) can accumulate in the striatum through the blood-brain barrier and cause neurotoxicity. It is mainly due to the decrease of dopamine (DA) levels in the striatum, which leads to extrapyramidal dysfunction. Netrin-1, as an axon guidance factor, can regulate the normal transmission of DA. However, few people have explored the role of netrin-1 in Mn-induced neurotoxicity. The purpose of the present study is to verify whether overexposure of Mn inhibits the axon attractant netrin-1, thereby damaging dopaminergic neuronal and motor function of mice. Here, we found that excessive Mn exposure reduces the expression of striatum netrin-1, tyrosine hydroxylase, DA receptor D3, and dopamine transporter 1, and the levels of serum netrin-1, and promotes dopaminergic neuronal and striatum injury, leading to DA transmission and motor dysfunction. Notably, recombinant mouse netrin-1 protein significantly antagonized Mn-induced neurotoxicity. These findings suggest that netrin-1 participates in Mn-induced motor dysfunction. Our findings may provide an experimental basis for fully elucidating the effects of Mn-induced neurotoxicity.
Asunto(s)
Dopamina , Intoxicación por Manganeso , Animales , Axones/metabolismo , Dopamina/metabolismo , Neuronas Dopaminérgicas/metabolismo , Humanos , Manganeso/toxicidad , Intoxicación por Manganeso/metabolismo , Ratones , Netrina-1/farmacologíaRESUMEN
The GABAA receptor (GABAAR) plays important roles in the regulation of Mn-induced GnRH secretion in immature female rats. However, the underlying molecular mechanisms remain unknown. Here, we assessed whether FTO and its substrate m6A are correlated with GABAAR expression in GnRH neurons after treatment with Mn in vitro and in vivo. Our study indicated that Mn treatment increased the expression of GnRH mRNA and decreased the levels of GABAAR protein but had no effect on GABAAR mRNA. Moreover, Mn upregulated the levels of FTO and inhibited global cellular m6A levels and GABAAα2 mRNA m6A levels. Knockdown of FTO increased the expression of GABAAR protein and GABAAα2 mRNA m6A levels. Data from rat models further demonstrate that inhibition of FTO suppressed GABAAR protein expression in the hypothalamus, causing delayed puberty onset. Collectively, our findings suggest that FTO-dependent m6A demethylation plays a critical role in regulating GABAAR mRNA processing in GnRH neurons.
Asunto(s)
Hormona Liberadora de Gonadotropina , Pubertad Precoz , Dioxigenasa FTO Dependiente de Alfa-Cetoglutarato/genética , Dioxigenasa FTO Dependiente de Alfa-Cetoglutarato/metabolismo , Animales , Femenino , Hormona Liberadora de Gonadotropina/metabolismo , Hipotálamo/metabolismo , Neuronas/metabolismo , Pubertad Precoz/inducido químicamente , Pubertad Precoz/genética , Pubertad Precoz/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Maduración SexualRESUMEN
One of the major environmental factors that induce PD is Manganese (Mn). Cellular and molecular mechanism of parkinsonism caused by Mn has not been explored clearly. The results of in vivo and in vitro experiments showed that Mn exposure caused abnormal projection of dopaminergic neurons and decreased mRNA expression and protein levels of FTO. This is due to Mn-induced the upregulation of Foxo3a. Using the cell model of overexpression of FTO, we found that FTO could antagonize Mn-induced the down-regulation of axon guidance molecule ephrin-B2 through RNA-seq, MeRIP-qPCR, and RT-qPCR experiments. Through RIP-seq and actinomycin D experiments, it was found that FTO can up-regulate the mRNA m6A level of ephrin-B2, which can be recognized by YTHDF2 and degraded. Finally, it is proved that Mn induces dopaminergic neurons projection injury and motor dysfunction through Foxo3a/FTO/m6A/ephrin-B2/YTHDF2 signal pathway.