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Rationale: The aryl hydrocarbon receptor (AhR) functions in the regulation of intestinal inflammation, but knowledge of the underlying mechanisms in innate immune cells is limited. Here, we investigated the role of AhR in modulating the functions of macrophages in inflammatory bowel disease pathogenesis. Methods: The cellular composition of intestinal lamina propria CD45+ leukocytes in a dextran sulfate sodium (DSS)-induced mouse colitis model was determined by single-cell RNA sequencing. Macrophage pyroptosis was quantified by analysis of lactate dehydrogenase release, propidium iodide staining, enzyme-linked immunosorbent assay, western blot, and flow cytometry. Differentially expressed genes were confirmed by RNA-seq, RT-qPCR, luciferase assay, chromatin immunoprecipitation, and immunofluorescence staining. Results: AhR deficiency mediated dynamic remodeling of the cellular composition of intestinal lamina propria (LP) CD45+ immune cells in a colitis model, with a significant increase in monocyte-macrophage lineage. Mice with AhR deficiency in myeloid cells developed more severe dextran sulfate sodium induced colitis, with concomitant increased macrophage pyroptosis. Dietary supplementation with an AhR pre-ligand, indole-3-carbinol, conferred protection against colitis while protection failed in mice lacking AhR in myeloid cells. Mechanistically, AhR signaling inhibited macrophage pyroptosis by promoting ornithine decarboxylase 1 (Odc1) transcription, to enhance polyamine biosynthesis. The increased polyamine, particularly spermine, inhibited NLRP3 inflammasome assembly and subsequent pyroptosis by suppressing K+ efflux. AHR expression was positively correlated with ODC1 in intestinal mucosal biopsies from patients with ulcerative colitis. Conclusions: These findings suggest a functional role for the AhR/ODC1/polyamine axis in maintaining intestinal homeostasis, providing potential targets for treatment of inflammatory bowel disease.
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Colitis , Sulfato de Dextran , Macrófagos , Poliaminas , Piroptosis , Receptores de Hidrocarburo de Aril , Receptores de Hidrocarburo de Aril/metabolismo , Receptores de Hidrocarburo de Aril/genética , Animales , Ratones , Macrófagos/metabolismo , Macrófagos/inmunología , Colitis/metabolismo , Colitis/inducido químicamente , Colitis/patología , Humanos , Poliaminas/metabolismo , Modelos Animales de Enfermedad , Ratones Endogámicos C57BL , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patología , Ratones Noqueados , Inflamación/metabolismo , Masculino , Enfermedades Inflamatorias del Intestino/metabolismo , Enfermedades Inflamatorias del Intestino/patología , Factores de Transcripción con Motivo Hélice-Asa-Hélice BásicoRESUMEN
As demonstrated in previous research, hsa_circ_0052602 (circODC1) is dynamically expressed in HPV-positive cervical cancer (CC). CircODC1 expression was quantified using qRT-PCR, and its role in CC cell growth was assessed via loss-of-function assays. Interactions between miR-607 and circODC1 or ODC1 were confirmed using bioinformatics and mechanistic assays. The association of FOXA1 with the circODC1 promoter was validated through ChIP and luciferase reporter assays. CircODC1 was highly expressed in HPV-positive CC cell lines, and its depletion significantly impeded malignant processes such as proliferation, migration, and invasion. We found that ODC1 also played an oncogenic role in HPV-positive CC cells. CircODC1 was shown to positively regulate ODC1 as a ceRNA, competitively binding to miR-607 to counteract its suppression of ODC1. HPV-associated FOXA1 was identified as a potential transcription factor of circODC1. Restoration experiments showed that overexpression of circODC1 could counterbalance the inhibitory effect of FOXA1 knockdown. These findings offer new insights into therapeutic strategies for HPV-positive CC patients.
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Proliferación Celular , Factor Nuclear 3-alfa del Hepatocito , Ornitina Descarboxilasa , Neoplasias del Cuello Uterino , Femenino , Humanos , Línea Celular Tumoral , Regulación Neoplásica de la Expresión Génica , Factor Nuclear 3-alfa del Hepatocito/metabolismo , Factor Nuclear 3-alfa del Hepatocito/genética , MicroARNs/genética , MicroARNs/metabolismo , Infecciones por Papillomavirus/virología , Infecciones por Papillomavirus/genética , ARN Circular/genética , ARN Circular/metabolismo , Neoplasias del Cuello Uterino/virología , Neoplasias del Cuello Uterino/genética , Neoplasias del Cuello Uterino/patología , Neoplasias del Cuello Uterino/metabolismo , Ornitina Descarboxilasa/genética , Ornitina Descarboxilasa/metabolismoRESUMEN
Activating Nrf2 by small molecules is a promising strategy to treat postmenopausal osteoporosis. However, there is currently no Nrf2 activator approved for treating chronic diseases, and the downstream mechanism underlying the regulation of Nrf2 on osteoclast differentiation remains unclear. Here, we found that bitopertin, a clinical-stage glycine uptake inhibitor, suppresses osteoclast differentiation and ameliorates ovariectomy-induced bone loss by activating Nrf2. Mechanistically, bitopertin interacts with the Keap1 Kelch domain and decreases Keap1-Nrf2 binding, leading to reduced Nrf2 ubiquitination and degradation. Bitopertin is associated with less adverse events than clinically approved Nrf2 activators in both mice and human subjects. Furthermore, Nrf2 transcriptionally activates ferroportin-coding gene Slc40a1 to reduce intracellular iron levels in osteoclasts. Loss of Nrf2 or iron supplementation upregulates ornithine-metabolizing enzyme Odc1, which decreases ornithine levels and thereby promotes osteoclast differentiation. Collectively, our findings identify a novel clinical-stage Nrf2 activator and propose a novel Nrf2-iron-ornithine metabolic axis in osteoclasts.
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Diferenciación Celular , Hierro , Ratones Endogámicos C57BL , Factor 2 Relacionado con NF-E2 , Osteoclastos , Factor 2 Relacionado con NF-E2/metabolismo , Animales , Diferenciación Celular/efectos de los fármacos , Osteoclastos/metabolismo , Osteoclastos/efectos de los fármacos , Osteoclastos/citología , Ratones , Hierro/metabolismo , Humanos , Proteína 1 Asociada A ECH Tipo Kelch/metabolismo , Femenino , Proteínas de Transporte de CatiónRESUMEN
Non-small-cell lung cancer (NSCLC), a common malignant tumor, requires deeper pathogenesis investigation. Autophagy is an evolutionarily conserved lysosomal degradation process that is frequently blocked during cancer progression. It is an urgent need to determine the novel autophagy-associated regulators in NSCLC. Here, we found that pirin was upregulated in NSCLC, and its expression was positively correlated with poor prognosis. Overexpression of pirin inhibited autophagy and promoted NSCLC proliferation. We then performed data-independent acquisition-based quantitative proteomics to identify the differentially expressed proteins (DEPs) in pirin-overexpression (OE) or pirin-knockdown (KD) cells. Among the pirin-regulated DEPs, ornithine decarboxylase 1 (ODC1) was downregulated in pirin-KD cells while upregulated along with pirin overexpression. ODC1 depletion reversed the pirin-induced autophagy inhibition and pro-proliferation effect in A549 and H460 cells. Immunohistochemistry showed that ODC1 was highly expressed in NSCLC cancer tissues and positively related with pirin. Notably, NSCLC patients with pirinhigh/ODC1high had a higher risk in terms of overall survival. In summary, we identified pirin and ODC1 as a novel cluster of prognostic biomarkers for NSCLC and highlighted the potential oncogenic role of the pirin/ODC1/autophagy axis in this cancer type. Targeting this pathway represents a possible therapeutic approach to treat NSCLC.
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Autofagia , Carcinoma de Pulmón de Células no Pequeñas , Proliferación Celular , Progresión de la Enfermedad , Neoplasias Pulmonares , Ornitina Descarboxilasa , Femenino , Humanos , Masculino , Células A549 , Autofagia/genética , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/patología , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Línea Celular Tumoral , Proliferación Celular/genética , Regulación Neoplásica de la Expresión Génica , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/metabolismo , Ornitina Descarboxilasa/metabolismo , Ornitina Descarboxilasa/genética , Pronóstico , Regulación hacia ArribaRESUMEN
BACKGROUND: Hypoxia contributes to cancer progression through various molecular mechanisms and hepatocellular carcinoma (HCC) is one of the most hypoxic malignancies. Hypoxia-inducible gene domain protein-1a (HIGD1A) is typically induced via epigenetic regulation and promotes tumor cell survival during hypoxia. However, the role of HIGD1A in HCC remains unknown. METHODS: HIGD1A expression was determined in 24 pairs of human HCC samples and para-tumorous tissues. Loss-of-function experiments were conducted both in vivo and in vitro to explore the role of HIGD1A in HCC proliferation and metastasis. RESULTS: Increased HIGD1A expression was found in HCC tissues and cell lines, which was induced by hypoxia or low-glucose condition. Moreover, HIGD1A knockdown in HCC cells arrested the cell cycle at the G2/M phase and promoted hypoxia-induced cell apoptosis, resulting in great inhibition of cell proliferation, migration, and invasion, as well as tumor xenograft formation. Interestingly, these anti-tumor effects were not observed in normal hepatocyte cell line L02. Further, HIGD1A knockdown suppressed the expression of ornithine decarboxylase 1 (ODC1), a rate-limiting enzyme of polyamine metabolism under c-Myc regulation. HIGD1A was found to bind with the c-Myc promoter region, and its knockdown decreased the levels of polyamine metabolites. Consistently, the inhibitory effect on HCC phenotype by HIGD1A silencing could be reversed by overexpression of c-Myc or supplementation of polyamines. CONCLUSIONS: Our results demonstrated that HIGD1A activated c-Myc-ODC1 nexus to regulate polyamine synthesis and to promote HCC survival and malignant phenotype, implying that HIGD1A might represent a novel therapeutic target for HCC.
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Chronic kidney disease (CKD) is well recognized as a distinct contributor to cardiac hypertrophy, while the underlying mechanism remains incompletely understood. Here, the authors show that myocardial mitochondrial oxidative damage is early and prominent in CKD and distinctively stimulates the STING-NFκB pathway by releasing mitochondrial DNA to drive cardiac hypertrophy. Furthermore, the authors reveal that ornithine decarboxylase (ODC1)-putrescine metabolic flux is transactivated by NFκB and is required for the STING-NFκB pathway to drive cardiac hypertrophy. Finally, genetic or pharmacologic inhibition of the myocardial mitochondria-STING-NFκB-ODC1 axis significantly prevents CKD-associated cardiac hypertrophy. Therefore, targeting the myocardial mitochoandria-STING-NFκB-ODC1 axis is a promising therapeutic strategy for cardiac hypertrophy in patients with CKD.
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Alzheimer's disease (AD) is one of the foremost neurodegenerative diseases, characterized by beta-amyloid (Aß) plaques and significant progressive memory loss. In AD, astrocytes are proposed to take up and clear Aß plaques. However, how Aß induces pathogenesis and memory impairment in AD remains elusive. We report that normal astrocytes show non-cyclic urea metabolism, whereas Aß-treated astrocytes show switched-on urea cycle with upregulated enzymes and accumulated entering-metabolite aspartate, starting-substrate ammonia, end-product urea, and side-product putrescine. Gene silencing of astrocytic ornithine decarboxylase-1 (ODC1), facilitating ornithine-to-putrescine conversion, boosts urea cycle and eliminates aberrant putrescine and its toxic byproducts ammonia and H2O2 and its end product GABA to recover from reactive astrogliosis and memory impairment in AD. Our findings implicate that astrocytic urea cycle exerts opposing roles of beneficial Aß detoxification and detrimental memory impairment in AD. We propose ODC1 inhibition as a promising therapeutic strategy for AD to facilitate removal of toxic molecules and prevent memory loss.
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Enfermedad de Alzheimer , Enfermedad de Alzheimer/metabolismo , Amoníaco/metabolismo , Péptidos beta-Amiloides/farmacología , Astrocitos/metabolismo , Humanos , Peróxido de Hidrógeno/metabolismo , Trastornos de la Memoria/metabolismo , Trastornos de la Memoria/patología , Placa Amiloide/metabolismo , Putrescina , Urea/metabolismoRESUMEN
Neuroblastoma (NB) is a devastating malignancy threatening children's health, and amplification of MYCN is associated with treatment failure and a poor outcome. Here, we aimed to demonstrate the role of cell division cycle 27 (CDC27), an important core subunit of the anaphase-promoting complex, and its clinical significance in NB patients. In functional assays, we illustrated that CDC27 promoted the cell growth, metastasis and sphere-formation ability of NB cells both in vitro and in vivo. To further understand the potential mechanism, SK-N-SH cells were transfected with CDC27 siRNA, and RNA-sequencing was performed. The results revealed that downregulation of CDC27 led to markedly reduced expression of ODC1, which is a well-established direct target of MYCN. Subsequently, we further illustrated that suppression of ODC1 significantly attenuated the promotion effect of CDC27 on the proliferation, metastasis, and sphere-formation ability of NB cells, hinting that CDC27 exerted its biological behavior in NB at least partly in an ODC1-dependent manner. In addition, CDC27 rendered cells more vulnerable to ferroptosis, while knockdown of ODC1 markedly reversed the pro-ferroptotic effect of CDC27. Collectively, our data is the first to report that the CDC27/ODC1 axis promotes tumorigenesis and acts as a positive regulator of ferroptosis in NB, highlighting that CDC27 may represent a novel therapeutic strategy and prognostic biomarker in neuroblastoma.
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Both viruses and host cells compete for intracellular polyamines for efficient propagation. Currently, how the key polyamine-metabolizing enzymes, including ornithine decarboxylase 1 (ODC1) and its antizyme 1 (OAZ1), are activated to co-ordinate viral propagation and polyamine biosynthesis remains unknown. Here, we report that the matrix protein of rice stripe mosaic virus (RSMV), a cytorhabdovirus, directly hijacks OAZ1 to ensure the proper assembly of rigid bacilliform non-enveloped virions in leafhopper vector. Viral matrix protein effectively competes with ODC1 to bind to OAZ1, and thus, the ability of OAZ1 to target and mediate the degradation of ODC1 is significantly inhibited during viral propagation, which finally promotes polyamines production. Thus, OAZ1 and ODC1 are activated to synergistically promote viral persistent propagation and polyamine biosynthesis in viruliferous vectors. Our data suggest that it is a novel mechanism for rhabdovirus to exploit OAZ1 for facilitating viral assembly.
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Multiple myeloma (MM) is a hematological malignancy worldwide in urgent need for novel therapeutic strategies. Since Velcade (bortezomib) was approved for the treatment of relapsed/refractory MM in 2003, we have seen considerable improvement in extending MM patient survival. However, most patients are fraught with high recurrence rate and incurability. Acupuncture is known for alleviating patient symptoms and improving the quality of life, but it is not well investigated in MM, especially in combination with bortezomib. In this study, we employed LC-MS and UHPLC-MS together with bioinformatics methods to test serum samples from 5TMM3VT MM murine model mice with four different treatments [control (C) group, bortezomib (V) treatment group, acupuncture (A) group, and combined (VA) group]. MM mice in group VA had longer survival time than mice in group A or group V. Joint pathway analysis indicated the underlying arginine and proline metabolism pathway among the 32 significantly decreased metabolites in group VA. CCK-8 assay and in vivo experiments validated that ornithine, the metabolite of arginine, promoted MM cell proliferation. In addition, gene expression omnibus (GEO) database analysis suggested that MM patients with higher ornithine decarboxylase 1 (ODC1) expression were evidently associated with poor overall survival. In summary, this study demonstrates the synergistic effects of acupuncture and bortezomib on extending the survival of MM model mice and provides potential therapeutic targets in the treatment of MM.
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Bachmann-Bupp syndrome (BABS) is a rare syndrome caused by gain-of-function variants in the C-terminus of ornithine decarboxylase (ODC coded by the ODC1 gene). BABS is characterized by developmental delay, macrocephaly, macrosomia, and an unusual pattern of non-congenital alopecia. Recent diagnosis of four more BABS patients provides further characterization of the phenotype of this syndrome including late-onset seizures in the oldest reported patient at 23 years of age, representing the first report for this phenotype in BABS. Neuroimaging abnormalities continue to be an inconsistent feature of the syndrome. This may be related to the yet unknown impact of ODC/polyamine dysregulation on the developing brain in this syndrome. Variants continue to cluster, providing support to a universal biochemical mechanism related to elevated ODC protein, enzyme activity, and abnormalities in polyamine levels. Recommendations for medical management can now be suggested as well as the potential for targeted molecular or metabolic testing when encountering this unique phenotype. The natural history of this syndrome will evolve with difluoromethylornithine (DFMO) therapy and raise new questions for further study and understanding.
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Alopecia/genética , Discapacidades del Desarrollo/genética , Transportadores de Ácidos Dicarboxílicos/genética , Megalencefalia/genética , Proteínas de Transporte de Membrana Mitocondrial/genética , Adolescente , Adulto , Alopecia/diagnóstico , Alopecia/tratamiento farmacológico , Alopecia/patología , Encéfalo/anomalías , Encéfalo/diagnóstico por imagen , Encéfalo/metabolismo , Niño , Preescolar , Discapacidades del Desarrollo/diagnóstico , Discapacidades del Desarrollo/diagnóstico por imagen , Discapacidades del Desarrollo/tratamiento farmacológico , Eflornitina/uso terapéutico , Femenino , Predisposición Genética a la Enfermedad , Humanos , Lactante , Recién Nacido , Masculino , Megalencefalia/diagnóstico por imagen , Megalencefalia/tratamiento farmacológico , Megalencefalia/patología , Neuroimagen , Fenotipo , Poliaminas/metabolismo , Convulsiones/diagnóstico , Convulsiones/tratamiento farmacológico , Convulsiones/genética , Convulsiones/patología , Adulto JovenRESUMEN
Ornithine decarboxylase (ODC1), a critical regulatory enzyme in polyamine biosynthesis, is a direct transcriptional target of MYCN, amplification of which is a powerful marker of aggressive neuroblastoma. A single nucleotide polymorphism (SNP), G316A, within the first intron of ODC1, results in genotypes wildtype GG, and variants AG/AA. CRISPR-cas9 technology was used to investigate the effects of AG clones from wildtype MYCN-amplified SK-N-BE(2)-C cells and the effect of the SNP on MYCN binding, and promoter activity was investigated using EMSA and luciferase assays. AG clones exhibited decreased ODC1 expression, growth rates, and histone acetylation and increased sensitivity to ODC1 inhibition. MYCN was a stronger transcriptional regulator of the ODC1 promoter containing the G allele, and preferentially bound the G allele over the A. Two neuroblastoma cohorts were used to investigate the clinical impact of the SNP. In the study cohort, the minor AA genotype was associated with improved survival, while poor prognosis was associated with the GG genotype and AG/GG genotypes in MYCN-amplified and non-amplified patients, respectively. These effects were lost in the GWAS cohort. We have demonstrated that the ODC1 G316A polymorphism has functional significance in neuroblastoma and is subject to allele-specific regulation by the MYCN oncoprotein.
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AIMS: We had previously reported that addition of putrescine to the culture medium was reported to reduce methylmercury toxicity in C17.2 neural stem cells. Here, we have examined the inhibition of methylmercury-induced cytotoxicity by putrescine using ODC1-overexpressing C17.2 cells. MATERIALS AND METHODS: We established stable ODC1-overexpressing C17.2 cells and evaluated methylmercury-induced apoptosis by examining the TUNEL assay and cleaved caspase-3 levels. Mitochondria-mediated apoptosis was also evaluated by reduction of mitochondrial membrane potential and recruitment of Bax and Bak to the mitochondria. KEY FINDINGS: ODC is encoded by ODC1 gene, and putrescine levels in ODC1-overexpressing cells were significantly higher than in control cells. Overexpression of ODC1 and addition of putrescine to the culture medium suppressed DNA fragmentation and caspase-3 activation, which are observed when apoptosis is induced by methylmercury. Moreover, mitochondrial dysfunction and reactive oxygen species (ROS) generation, caused by methylmercury, were also inhibited by the overexpression of ODC1 and putrescine; pretreatment with ODC inhibitor, however, promoted both ROS generation and apoptosis by methylmercury. Finally, we found that Bax and Bak, the apoptosis-promoting factors, to be increased in mitochondria, following methylmercury treatment, and the same was inhibited by overexpression of ODC1. These results suggest that overexpression of ODC1 may prevent mitochondria-mediated apoptosis by methylmercury via increase of putrescine levels. SIGNIFICANCE: Our findings provide important clues to clarify mechanisms involved in the defense against methylmercury toxicity and suggest novel biological functions of putrescine.
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Compuestos de Metilmercurio/toxicidad , Mitocondrias/efectos de los fármacos , Células-Madre Neurales/efectos de los fármacos , Ornitina Descarboxilasa/genética , Putrescina/farmacología , Animales , Apoptosis/efectos de los fármacos , Línea Celular , Etiquetado Corte-Fin in Situ , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Ratones , Mitocondrias/patología , Células-Madre Neurales/patologíaRESUMEN
Current treatments of hepatitis B virus (HBV) are limited to Interferon-alpha or the nucleos(t)ide analogs antiviral therapies, and it is crucial to develop and define new antiviral drugs to cure HBV. In this study, we explored the anti-HBV effect of difluoromethylornithine (DFMO), an irreversibly inhibitor of decarboxylase 1(ODC1) on HBV replication. Firstly, we found that polyamines contributed to HBV DNA replication via increasing levels of the HBV core protein (HBc) and capsids. In contrast, depletion of polyamines either by silencing the expression of ODC1 or DFMO treatment, resulted in decreasing viral DNA replication and levels of HBc protein and capsids. Furthermore, we found that DFMO decreased the stability of the HBc protein without affecting mRNA transcription and protein translation. Taken together, our findings demonstrate that DFMO inhibits HBV replication by reducing HBc stability and this may provide a new approach for HBV therapeutics.
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Carboxiliasas , Virus de la Hepatitis B , Replicación Viral , Antivirales/farmacología , Carboxiliasas/antagonistas & inhibidores , Replicación del ADN , ADN Viral , Eflornitina/farmacología , Virus de la Hepatitis B/efectos de los fármacos , Virus de la Hepatitis B/fisiología , HumanosRESUMEN
Traumatic brain injury (TBI) causes permanent neurological and cognitive impairments. Effective pharmacological interventions remain elusive. Spermidine is a polyamine compound found in our body that may play a role in brain development and congenital function. In this study, we aimed to investigate the therapeutic potential of spermidine for TBI. We employed experimental closed head injury (CHI) model to evaluate the protective function of spermidine on brain injury. We assessed the neurobehavioral function recovery using Neurologic Severity Score (NSS) and Morris water maze test. At histological level, we evaluated the improvement on brain edema, brain-blood barrier integrity, and cell apoptosis. We also measured inflammatory cytokines and brain injury biomarkers to monitor the treatment outcomes. Last, we correlated the level of spermidine with CHI animal model and TBI patients with different levels of severity. Spermidine administration post-CHI was found effectively to accelerate NSS improvement and shorten latency in maze test. We observed consistent improvements in brain edema, BBB function, and cell death in spermidine-treated group. Inflammatory cytokines and TBI biomarkers, e.g., S100B, MBP and CFAP were reduced significantly in treatment group. Interestingly, inhibiting spermidine synthesis influenced the neurobehavioral recovery in CHI mice. ODC1, a rate-limiting enzyme for spermidine synthesis, was found lower in CHI mice. Serum level of spermidine was significantly lower in TBI patients with severe pathological scores. Spermidine pathway may carry an endogenous role in pathophysiological process of CHI. For the first time, we demonstrated that administrating spermidine may provide a new treatment for TBI.
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Lesiones Traumáticas del Encéfalo/tratamiento farmacológico , Fármacos Neuroprotectores/uso terapéutico , Espermidina/uso terapéutico , Adulto , Animales , Lesiones Traumáticas del Encéfalo/sangre , Modelos Animales de Enfermedad , Femenino , Humanos , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Ratones Endogámicos BALB C , Proteínas del Tejido Nervioso/sangre , Fármacos Neuroprotectores/química , Fármacos Neuroprotectores/farmacología , Espermidina/sangre , Espermidina/química , Espermidina/farmacologíaRESUMEN
Retinoblastoma (RB) is the most common intraocular malignancy in infants and children. S-phase kinase-associated protein 2 (SKP2) has been unmasked as an oncogene in a great many of carcinomas. The biologic function and the detailed molecular mechanism of SKP2 in RB need to be better understood. In this study, real-time quantitative polymerase chain reaction and Western blot showed the ectopic expression of SKP2 in RB tissues and cell lines. Loss of function assays showed the attenuated cell proliferation in RB as a result of SKP2 knockdown. In addition, bioinformatics analysis predicted the interaction between SKP2 and miR-422a. Luciferase reporter assay and Pearson's correlation analysis validated the negative correlation between miR-422a and SKP2. MiR-422a overexpression led to a decline of SKP2 expression and cell growth in RB. The binding capacity between miR-422a and circ_ODC1 was also predicted by bioinformatics analysis. Pearson's correlation analysis and luciferase reporter assay confirmed that circ_ODC1 is negatively correlated with miR-422a. Silencing circ_ODC1 resulted in a rise in miR-422a expression and RB cell growth. Moreover, reduced cell growth was restored by SKP2 overexpression. In a word, SKP2, induced by circ_ODC1 and miR-422a, promotes RB proliferation. Our new findings in this research might expedite the discovery of novel prognostic markers and therapeutic targets of RB.
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Transportadores de Ácidos Dicarboxílicos/metabolismo , MicroARNs/metabolismo , Proteínas de Transporte de Membrana Mitocondrial/metabolismo , ARN Circular/metabolismo , Neoplasias de la Retina/patología , Retinoblastoma/patología , Proteínas Quinasas Asociadas a Fase-S/metabolismo , Algoritmos , Animales , Línea Celular Tumoral , Núcleo Celular/metabolismo , Proliferación Celular , Biología Computacional , Citoplasma/metabolismo , Regulación Neoplásica de la Expresión Génica , Humanos , Masculino , Ratones , Ratones Desnudos , Trasplante de Neoplasias , Regiones Promotoras Genéticas , Unión Proteica , Neoplasias de la Retina/metabolismo , Retinoblastoma/metabolismo , Proteínas de Unión a Retinoblastoma/metabolismo , Transfección , Ubiquitina-Proteína Ligasas/metabolismo , Regulación hacia ArribaRESUMEN
Polyamines are low molecular weight, organic cations that play a critical role in many major cellular processes including cell cycle regulation and apoptosis, cellular division, tissue proliferation, and cellular differentiation; however, the functions of polyamines in regulating the storage of metabolic fuels such as triglycerides and glycogen is poorly understood. To address this question, we focused on the Drosophila homolog of ornithine decarboxylase (Odc1), the first rate-limiting enzyme in the synthesis of polyamines. Mutants in Odc1 are lethal, but heterozygotes were viable to adulthood. Odc1 heterozygotes appeared larger than their genetic background control flies and consistent with this observation, weighed more than the controls. However, the increased weight was not due to increased food consumption as heterozygotes ate less than the controls. Interestingly, Odc1 heterozygous flies had augmented triglyceride storage, and this lipid phenotype was due to increased triglyceride storage per cell and an increase in the number of fat cells produced. Odc1 heterozygous flies also displayed increased expression of the lipid synthesis genes fatty acid synthase (FASN) and acetyl-CoA carboxylase (ACC), suggesting increased lipid synthesis was the cause of the augmented triglyceride phenotype. These results provide a link between the expression of Odc1 and triglyceride storage suggesting that the polyamine pathway plays a role in regulating lipid metabolism.
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Proteínas de Drosophila/genética , Drosophila melanogaster/metabolismo , Ornitina Descarboxilasa/genética , Triglicéridos/metabolismo , Acetil-CoA Carboxilasa/genética , Acetil-CoA Carboxilasa/metabolismo , Animales , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Acido Graso Sintasa Tipo I/genética , Acido Graso Sintasa Tipo I/metabolismo , Ácidos Grasos/genética , Ácidos Grasos/metabolismo , Femenino , Regulación de la Expresión Génica , Heterocigoto , Mutación , Ornitina Descarboxilasa/metabolismo , Triglicéridos/genéticaRESUMEN
Polyamines serve a number of vital functions in humans, including regulation of cellular proliferation, intracellular signaling, and modulation of ion channels. Ornithine decarboxylase 1 (ODC1) is the rate-limiting enzyme in endogenous polyamine synthesis. In this report, we present four patients with a distinct neurometabolic disorder associated with de novo heterozygous, gain-of-function variants in the ODC1 gene. This disorder presents with global developmental delay, ectodermal abnormalities including alopecia, absolute or relative macrocephaly, and characteristic facial dysmorphisms. Neuroimaging variably demonstrates white matter abnormalities, prominent Virchow-Robin spaces, periventricular cysts, and abnormalities of the corpus callosum. Plasma clinical metabolomics analysis demonstrates elevation of N-acetylputrescine, the acetylated form of putrescine, with otherwise normal polyamine levels. Therapies aimed at reducing putrescine levels, including ODC1 inhibitors, dietary interventions, and antibiotics to reduce polyamine production by gastrointestinal flora could be considered as disease-modifying therapies. As the ODC1 gene has been implicated in neoplasia, cancer surveillance may be important in this disorder.
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Alopecia/genética , Trastorno Dismórfico Corporal/genética , Transportadores de Ácidos Dicarboxílicos/genética , Mutación con Ganancia de Función , Megalencefalia/genética , Proteínas de Transporte de Membrana Mitocondrial/genética , Trastornos del Neurodesarrollo/genética , Adolescente , Alelos , Alopecia/diagnóstico , Trastorno Dismórfico Corporal/diagnóstico , Encéfalo/anomalías , Encéfalo/diagnóstico por imagen , Niño , Electroencefalografía , Facies , Femenino , Genotipo , Humanos , Masculino , Megalencefalia/diagnóstico , Mutación , Trastornos del Neurodesarrollo/diagnóstico , Neuroimagen/métodos , Pruebas Neuropsicológicas , Fenotipo , Polimorfismo de Nucleótido SimpleRESUMEN
Macrophage activation plays a critical role in the innate immune response. Ornithine decarboxylase (ODC1) metabolizes l-ornithine to polyamines and is the rate-limiting enzyme involved in the metabolism of polyamines, which are reportedly involved in cell differentiation, proliferation, and migration. However, the function of ODC1 in immune cells and especially in macrophages, as well as its underlying molecular mechanism, remains unclear. This study revealed the potential ODC1 function and mechanism associated with the lipopolysaccharide (LPS)-, Bacillus Calmette-Guerin (BCG)-, or carbon tetrachloride (CCl4)-induced inflammatory response in macrophages. We found significant upregulation of ODC1 in macrophages following LPS simulation and ODC1-specific suppression of proinflammatory cytokine secretion from macrophages upon stimulation with LPS, BCG and CCl4, respectively, suggesting a role as a common control element of the inflammatory response. Western blotting for nuclear factor-κB and mitogen-activated protein kinases revealed significant inhibition of phosphorylation of multiple transcription factors following ODC1 overexpression in macrophages. Moreover, ODC1 inhibited reactive oxygen species-induced and caspase-dependent apoptosis highlighted by decreased caspase-3 and -9 expression following ODC1 upregulation. These findings indicated that ODC1 was involved in attenuating the inflammatory response upon stimulation of macrophages, making it a potential therapeutic target for inflammatory diseases.
Asunto(s)
Apoptosis , Inflamación/metabolismo , Macrófagos/metabolismo , Ornitina Descarboxilasa/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Animales , Células Cultivadas , Citocinas/genética , Citocinas/metabolismo , Expresión Génica/efectos de los fármacos , Inflamación/enzimología , Lipopolisacáridos/farmacología , Macrófagos/citología , Macrófagos/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , FN-kappa B/metabolismo , Ornitina Descarboxilasa/genética , Fosforilación , Células RAW 264.7 , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismoRESUMEN
Breast cancer is a heterogeneous and multifactorial disease with variable disease progression risk, and treatment response. Urtica dioica is a traditional herb used as an adjuvant therapeutic agent in cancer. In the present study, we have evaluated the effects of the aqueous extract of Urtica dioica on Adenosine deaminase (ADA) and Ornithine decarboxylase (ODC1) gene expression in MCF-7, MDA-MB-231, two breast cancer cell lines being estrogen receptor positive and estrogen receptor negative, respectively. Cell lines were cultured in suitable media. After 24 h, different concentrations of the extract were added and after 72 h, ADA and ODC1 gene expression as well as BCL2 and BAX apoptotic genes were assessed by Taqman real time PCR assay. Cells viability was assessed by MTT assay, and apoptosis was also evaluated at cellular level. The intra and extracellular levels of ODC1 and ADA enzymes were evaluated by ELISA. Results showed differential expression of ADA and ODC1 genes in cancer cell lines. In MCF-7 cell line, the expression level of ADA was upregulated in a dose-dependent manner but its expression did not change in MDA-MB cell line. ODC1 expression was increased in both examined cell lines. Also, increased level of the apoptotic BAX/BCL-2 ratio was detected in MCF-7 cells. These results demonstrated that Urtica dioica induces apoptosis in breast cancer cells by influencing ODC1 and ADA genes expression, and estrogen receptors. The different responses observed with these cell lines could be due to the interaction of Urtica dioica as a phytoestrogen with the estrogen receptor.