RESUMEN
Chronic renal failure (CRF) is an incurable disease with unique challenges. Anemia is a frequent complication affecting dialysis patients. Erythropoietin (EPO) is used to treat anemia, but a poor response may result. We investigated genetic polymorphisms of store-operated calcium channel (SOC) signaling, an important erythropoietin-activated pathway that may induce EPO resistance in patients with renal failure. A total of 108 end stage renal disease (ESRD) patients were selected for this study. Patients were divided into two groups according to their erythropoietin resistance index (ERI): 39 patients with an ERI>10 and 69 patients with an ERI<10. We selected four tagging single nucleotide polymorphisms (tSNPs) in STIM1 and five in ORAI1 in our study. A polymerase chain reaction was performed, and genotyping against EPO resistance was correlated. Patients with the AG genotype of rs1561876 in STIM1, the TC genotype of rs6486795 in ORAI1, and the TG or GG genotypes of rs12320939 in ORAI1 were associated with an increased risk of erythropoietin resistance. Overall, we reported a moderately significant relationship between genetic polymorphisms of STIM1 and EPO resistance. We also reported a highly significant relationship between genetic polymorphisms of ORAI1 and EPO resistance. The (A-A-G) haplotype of STIM1 and the (G-T-G-T-A, G-C-G-C-G, or G-T-T-C-G) haplotypes of ORAI1 were significantly associated with EPO resistance.
Asunto(s)
Eritropoyetina , Fallo Renal Crónico , Proteínas de Neoplasias , Proteína ORAI1 , Polimorfismo de Nucleótido Simple , Molécula de Interacción Estromal 1 , Humanos , Molécula de Interacción Estromal 1/genética , Egipto , Fallo Renal Crónico/genética , Masculino , Eritropoyetina/genética , Femenino , Proteína ORAI1/genética , Persona de Mediana Edad , Proteínas de Neoplasias/genética , Adulto , Resistencia a Medicamentos/genéticaRESUMEN
Erythropoietin (EPO) plays a key role in energy metabolism, with EPO receptor (EpoR) expression in white adipose tissue (WAT) mediating its metabolic activity. Here, we show that male mice lacking EpoR in adipose tissue exhibit increased fat mass and susceptibility to diet-induced obesity. Our findings indicate that EpoR is present in WAT, brown adipose tissue, and skeletal muscle. Elevated EPO in male mice improves glucose tolerance and insulin sensitivity while reducing expression of lipogenic-associated genes in WAT, which is linked to an increase in transcription factor RUNX1 that directly inhibits lipogenic genes expression. EPO treatment in wild-type male mice decreases fat mass and lipogenic gene expression and increase in RUNX1 protein in adipose tissue which is not observed in adipose tissue EpoR ablation mice. EPO treatment decreases WAT ubiquitin ligase FBXW7 expression and increases RUNX1 stability, providing evidence that EPO regulates energy metabolism in male mice through the EPO-EpoR-RUNX1 axis.
Asunto(s)
Tejido Adiposo Blanco , Subunidad alfa 2 del Factor de Unión al Sitio Principal , Metabolismo Energético , Eritropoyetina , Receptores de Eritropoyetina , Animales , Eritropoyetina/metabolismo , Eritropoyetina/genética , Subunidad alfa 2 del Factor de Unión al Sitio Principal/metabolismo , Subunidad alfa 2 del Factor de Unión al Sitio Principal/genética , Masculino , Metabolismo Energético/efectos de los fármacos , Ratones , Receptores de Eritropoyetina/metabolismo , Receptores de Eritropoyetina/genética , Tejido Adiposo Blanco/metabolismo , Ratones Noqueados , Ratones Endogámicos C57BL , Obesidad/metabolismo , Obesidad/genética , Músculo Esquelético/metabolismo , Resistencia a la Insulina , Lipogénesis/genética , Lipogénesis/efectos de los fármacos , Tejido Adiposo Pardo/metabolismo , Transducción de Señal/efectos de los fármacosRESUMEN
Enucleated erythrocytes are characteristic of adult mammals. In contrast, fish, amphibians, reptiles, birds, and fetal mammals possess nucleated erythrocytes in their circulation. Erythroid maturation is regulated by erythropoietin (EPO) and its receptor (EPOR), which are conserved among vertebrates. In mammals, EPOR on the erythroid progenitor membrane disappears after terminal differentiation. However, in western clawed frog, Xenopus tropicalis, mature erythrocytes maintain EPOR expression, suggesting that they have non-canonical functions of the EPO-EPOR axis rather than proliferation and differentiation. In this study, we investigated the non-canonical functions of EPOR in Xenopus mature erythrocytes. EPO stimulation of peripheral erythrocytes did not induce proliferation but induced phosphorylation of intracellular proteins, including signal transducer and activator of transcription 5 (STAT5). RNA-Seq analysis of EPO-stimulated peripheral erythrocytes identified 45 differentially expressed genes (DEGs), including cytokine inducible SH2 containing protein gene (cish) and suppressor of cytokine signaling 3 gene (socs3), negative regulators of the EPOR-Janus kinase (JAK)-STAT pathway. These phosphorylation studies and pathway analysis demonstrated the activation of the JAK-STAT pathway through EPO-EPOR signaling in erythrocytes. Through comparison with EPO-responsive genes in mouse erythroid progenitors obtained from a public database, we identified 31 novel EPO-responsive genes indicating non-canonical functions. Among these, we focused on ornithine decarboxylase 1 gene (odc1), which is the rate-limiting enzyme in polyamine synthesis and affects hematopoietic progenitor differentiation and the endothelial cell response to hypoxic stress. An EPO-supplemented culture of erythrocytes showed increased odc1 expression followed by a decrease in polyamine-rich erythrocytes, suggesting EPO-responsive polyamine excretion. These findings will advance our knowledge of the unknown regulatory systems under the EPO-EPOR axis and functional differences between vertebrates' nucleated and enucleated erythrocytes.
Asunto(s)
Eritrocitos , Eritropoyetina , Receptores de Eritropoyetina , Xenopus , Animales , Eritropoyetina/metabolismo , Eritropoyetina/genética , Receptores de Eritropoyetina/metabolismo , Receptores de Eritropoyetina/genética , Eritrocitos/metabolismo , Transducción de Señal , Regulación de la Expresión Génica , Eritroblastos/metabolismoRESUMEN
INTRODUCTION: In end stage renal disease )ESRD(, reduced EPO production resulted in decreased oxygen diffusion that cause Hypoxia-inducible factors (HIFs) stabilization. The mechanism of beneficial effects of H2S in chronic kidney disease (CKD) is the aim of the present study to examine the effects of the H2S donor sodium hydrosulfide (NaHS) on renal function parameters, oxidative stress indices and expression levels of HIF-2α gene and erythropoietin protein in 5/6 nephrectomy-induced chronic renal failure in rats. METHODS AND MATERIALS: Male rats were assigned into 3 groups (n = 8): Sham, CKD and NaHS groups. In the CKD group, 5/6 nephrectomy was performed. In the sham group, rats were anesthetized but 5/6 nephrectomy was not induced. In the NaHS group, 30 µmol/L of NaHS in drinking water for 8 weeks was adminstrated 4 weeks after 5/6 nephrectomy induction. At the end of the 12 week, blood and renal tissues were taken to evaluate renal function parameters, oxidative stress indices and expression levels of HIF-2α gene and erythropoietin protein. RESULTS: The induction of 5/6 nephrectomy significantly caused renal dysfunction, oxidative stress, increased HIF-2α gene expression and decreased erythropoietin levels in renal tissue samples. NaHS administration resulted in a marked improvement in renal function and oxidative stress indicators, a marked reduction in HIF-2α gene expression as well as an increase in erythropoietin protein levels in comparison with the CKD group. CONCLUSION: In this study, regional hypoxia and oxidative stress in CKD, may cause the stabilization of the HIFs complexes, although erythropoietin synthesis was not increased due to destructive effects of CKD on the kidney tissues. Administration of NaHS caused up-regulating HIF-erythropoietin signaling pathway.
Asunto(s)
Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Eritropoyetina , Sulfuro de Hidrógeno , Nefrectomía , Estrés Oxidativo , Insuficiencia Renal Crónica , Animales , Eritropoyetina/genética , Eritropoyetina/metabolismo , Eritropoyetina/farmacología , Masculino , Ratas , Sulfuro de Hidrógeno/metabolismo , Insuficiencia Renal Crónica/metabolismo , Insuficiencia Renal Crónica/tratamiento farmacológico , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Estrés Oxidativo/efectos de los fármacos , Riñón/metabolismo , Riñón/efectos de los fármacos , Regulación hacia Arriba/efectos de los fármacos , Sulfuros/farmacología , Modelos Animales de EnfermedadRESUMEN
With significant advancements in understanding gene functions and therapy, the potential misuse of gene technologies, particularly in the context of sports through gene doping (GD), has come to the forefront. This raises concerns regarding the need for point-of-care testing of various GD candidates to counter illicit practices in sports. However, current GD detection techniques, such as PCR, lack the portability required for on-site multiplexed detection. In this study, we introduce an integrated microfluidics-based chip for multiplexed gene doping detection, termed MGD-Chip. Through the strategic design of hydrophilic and hydrophobic channels, MGD-Chip enables the RPA and CRISPR-Cas12a assays to be sequentially performed on the device, ensuring minimal interference and cross-contamination. Six potential GD candidates were selected and successfully tested simultaneously on the platform within 1 h. Demonstrating exceptional specificity, the platform achieved a detection sensitivity of 0.1 nM for unamplified target plasmids and 1 aM for amplified ones. Validation using mouse models established by injecting IGFI and EPO transgenes confirmed the platform's efficacy in detecting gene doping in real samples. This technology, capable of detecting multiple targets using portable elements, holds promise for real-time GD detection at sports events, offering a rapid, highly sensitive, and user-friendly solution to uphold the integrity of sports competitions.
Asunto(s)
Técnicas Biosensibles , Sistemas CRISPR-Cas , Doping en los Deportes , Interacciones Hidrofóbicas e Hidrofílicas , Dispositivos Laboratorio en un Chip , Sistemas CRISPR-Cas/genética , Doping en los Deportes/prevención & control , Animales , Técnicas Biosensibles/instrumentación , Técnicas Biosensibles/métodos , Ratones , Humanos , Eritropoyetina/genética , Eritropoyetina/análisis , Diseño de Equipo , Proteínas Asociadas a CRISPR/genética , Proteínas Bacterianas , EndodesoxirribonucleasasRESUMEN
The regulation of iron (Fe) levels is essential to maintain an adequate supply for erythropoiesis, among other processes, and to avoid possible toxicity. The liver-produced peptide hepcidin is regarded as the main regulator of Fe absorption in enterocytes and release from hepatocytes and macrophages, as it impairs Fe export through ferroportin. The glycoprotein erythropoietin (Epo) drives erythroid progenitor survival and differentiation in the bone marrow, and has been linked to the mobilization of Fe reserves necessary for hemoglobin production. Herein we show that Epo inhibits hepcidin expression directly in the HepG2 hepatic cell line, thus leading to a decrease in intracellular Fe levels. Such inhibition was dependent on the Epo receptor-associated kinase JAK2, as well as on the PI3K/AKT/mTOR pathway, which regulates nutrient homeostasis. Epo was also found to decrease binding of the C/EBP-α transcription factor to the hepcidin promoter, which could be attributed to an increased expression of its inhibitor CHOP. Epo did not only hinder the stimulating effect of C/EBP-α on hepcidin transcription, but also favored hepcidin inhibition by HIF-1α, by increasing is nuclear translocation as well as its protein levels. Moreover, in assays with the inhibitor genistein, this transcription factor was found necessary for Epo-induced hepcidin suppression. Our findings support the involvement of the PI3K/AKT/mTOR pathway in the regulation of Fe levels by Epo, and highlight the contrasting roles of the C/EBP-α and HIF-1α transcription factors as downstream effectors of the cytokine in this process.
Asunto(s)
Proteína alfa Potenciadora de Unión a CCAAT , Eritropoyetina , Hepcidinas , Subunidad alfa del Factor 1 Inducible por Hipoxia , Hierro , Serina-Treonina Quinasas TOR , Humanos , Disponibilidad Biológica , Proteína alfa Potenciadora de Unión a CCAAT/metabolismo , Proteína alfa Potenciadora de Unión a CCAAT/genética , Regulación hacia Abajo/efectos de los fármacos , Eritropoyetina/metabolismo , Eritropoyetina/genética , Células Hep G2 , Hepcidinas/metabolismo , Hepcidinas/genética , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Hierro/metabolismo , Transducción de Señal/efectos de los fármacos , Serina-Treonina Quinasas TOR/metabolismoRESUMEN
Inherited non-hemolytic anemia is a group of rare bone marrow disorders characterized by erythroid defects. Although concerted efforts have been made to explore the underlying pathogenetic mechanisms of these diseases, the understanding of the causative mutations are still incomplete. Here we identify in a diseased pedigree that a gain-of-function mutation in toll-like receptor 8 (TLR8) is implicated in inherited non-hemolytic anemia. TLR8 is expressed in erythroid lineage and erythropoiesis is impaired by TLR8 activation whereas enhanced by TLR8 inhibition from erythroid progenitor stage. Mechanistically, TLR8 activation blocks annexin A2 (ANXA2)-mediated plasma membrane localization of STAT5 and disrupts EPO signaling in HuDEP2 cells. TLR8 inhibition improves erythropoiesis in RPS19+/- HuDEP2 cells and CD34+ cells from healthy donors and inherited non-hemolytic anemic patients. Collectively, we identify a gene implicated in inherited anemia and a previously undescribed role for TLR8 in erythropoiesis, which could potentially be explored for therapeutic benefit in inherited anemia.
Asunto(s)
Anemia , Eritropoyesis , Receptor Toll-Like 8 , Humanos , Eritropoyesis/genética , Receptor Toll-Like 8/metabolismo , Receptor Toll-Like 8/genética , Femenino , Anemia/genética , Masculino , Linaje , Eritropoyetina/metabolismo , Eritropoyetina/genética , Adulto , Transducción de Señal , Mutación , Células Eritroides/metabolismo , Animales , Células Precursoras Eritroides/metabolismoRESUMEN
Arsenic is widely present in the environment in trivalent and pentavalent forms; long-term arsenic exposure due to environmental pollution has become a problem. Previous reports have shown that 24-h exposure to arsenate (as pentavalent arsenic) potentiates erythropoietin (EPO) production via reactive oxygen species (ROS) in EPO-producing HepG2 cells. However, the effects of long-term arsenate exposure on EPO production remain unclear. In HepG2 cells subcultured for 3 weeks in the presence of arsenate, EPO mRNA levels were lower than those in untreated cells. Levels of ARSENITE METHYLTRANSFERASE mRNA, as well as those of Nuclear factor erythroid 2-related factor 2, glutathione, and superoxide dismutase proteins, were increased compared to untreated cells, but levels of malondialdehyde were not significantly altered. Thus, long-term exposure to arsenate enhances ROS scavenging, suggesting that the ROS-induced accumulation of EPO mRNA is attenuated by arsenate exposure. The induction of EPO accumulation by hypoxia also was attenuated by long-term arsenate exposure, suggesting an impairment in responsivity of EPO production. Furthermore, mRNA levels of SIRTUIN-1, which affects EPO transcription, were potentiated by long-term arsenate exposure. These results suggest that long-term arsenate exposure has multiple, distinct effects on EPO production in vitro.
Asunto(s)
Eritropoyetina , Especies Reactivas de Oxígeno , Humanos , Eritropoyetina/genética , Eritropoyetina/metabolismo , Células Hep G2 , Especies Reactivas de Oxígeno/metabolismo , Arseniatos/toxicidad , Sirtuina 1/metabolismo , Sirtuina 1/genética , ARN Mensajero/metabolismo , Factor 2 Relacionado con NF-E2/metabolismo , Factor 2 Relacionado con NF-E2/genética , Metiltransferasas/metabolismo , Metiltransferasas/genética , Glutatión/metabolismo , Superóxido Dismutasa/metabolismo , Arsénico/toxicidadRESUMEN
With the rapid development of gene therapy technology in recent years, its abuse as a method of sports doping in athletics has become a concern. However, there is still room for improvement in gene-doping testing methods, and a robust animal model needs to be developed. Therefore, the purposes of this study were to establish a model of gene doping using recombinant adeno-associated virus vector-9, including the human erythropoietin gene (rAAV9-hEPO), and to establish a relevant testing method. First, it was attempted to establish the model using rAAV9-hEPO on mice. The results showed a significant increase in erythrocyte volume accompanied by an increase in spleen weight, confirming the validity of the model. Next, we attempted to detect proof of gene doping by targeting DNA and RNA. Direct proof of gene doping was detected using a TaqMan-qPCR assay with certain primers/probes. In addition, some indirect proof was identified in RNAs through the combination of a TB Green qPCR assay with RNA sequencing. Taken together, these results could provide the foundation for an effective test for gene doping in human athletes in the future.
Asunto(s)
Dependovirus , Doping en los Deportes , Eritropoyetina , Vectores Genéticos , Eritropoyetina/genética , Animales , Ratones , Doping en los Deportes/métodos , Dependovirus/genética , Humanos , Vectores Genéticos/genética , Masculino , Terapia Genética/métodos , Modelos AnimalesRESUMEN
Human erythropoietin (hEPO) is one of the most in-demand biopharmaceuticals, however, its production is challenging. When produced in a plant expression system, hEPO results in extensive plant tissue damage and low expression. It is demonstrated that the modulation of the plant protein synthesis machinery enhances hEPO production. Co-expression of basic leucine zipper transcription factors with hEPO prevents plant tissue damage, boosts expression, and increases hEPO solubility. bZIP28 co-expression up-regulates genes associated with the unfolded protein response, indicating that the plant tissue damage caused by hEPO expression is due to the native protein folding machinery being overwhelmed and that this can be overcome by co-expressing bZIP28.
Asunto(s)
Factores de Transcripción con Cremalleras de Leucina de Carácter Básico , Eritropoyetina , Nicotiana , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Eritropoyetina/genética , Eritropoyetina/metabolismo , Humanos , Nicotiana/genética , Nicotiana/metabolismo , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Regulación de la Expresión Génica de las Plantas , Respuesta de Proteína Desplegada/genéticaRESUMEN
ABSTRACT: The regulation of red blood cell (RBC) homeostasis by erythropoietin (EPO) is critical for O2 transport and maintaining the adequate number of RBCs in vertebrates. Therefore, dysregulation in EPO synthesis results in disease conditions such as polycythemia in the case of excessive EPO production and anemia, which occurs when EPO is inadequately produced. EPO plays a crucial role in treating anemic patients; however, its overproduction can increase blood viscosity, potentially leading to fatal heart failure. Consequently, the identification of druggable transcription factors and their associated ligands capable of regulating EPO offers a promising therapeutic approach to address EPO-related disorders. This study unveils a novel regulatory mechanism involving 2 pivotal nuclear receptors (NRs), Rev-ERBA (Rev-erbα, is a truncation of reverse c-erbAa) and RAR-related orphan receptor A (RORα), in the control of EPO gene expression. Rev-erbα acts as a cell-intrinsic negative regulator, playing a vital role in maintaining erythropoiesis at the correct level. It accomplishes this by directly binding to newly identified response elements within the human and mouse EPO gene promoter, thereby repressing EPO production. These findings are further supported by the discovery that a Rev-erbα agonist (SR9011) effectively suppresses hypoxia-induced EPO expression in mice. In contrast, RORα functions as a positive regulator of EPO gene expression, also binding to the same response elements in the promoter to induce EPO production. Finally, the results of this study revealed that the 2 NRs, Rev-erbα and RORα, influence EPO synthesis in a negative and positive manner, respectively, suggesting that the modulating activity of these 2 NRs could provide a method to target disorders linked with EPO dysregulation.
Asunto(s)
Eritropoyetina , Regulación de la Expresión Génica , Miembro 1 del Grupo D de la Subfamilia 1 de Receptores Nucleares , Miembro 1 del Grupo D de la Subfamilia 1 de Receptores Nucleares/metabolismo , Miembro 1 del Grupo D de la Subfamilia 1 de Receptores Nucleares/genética , Eritropoyetina/metabolismo , Eritropoyetina/genética , Humanos , Animales , Ratones , Miembro 1 del Grupo F de la Subfamilia 1 de Receptores Nucleares/metabolismo , Miembro 1 del Grupo F de la Subfamilia 1 de Receptores Nucleares/genética , Eritropoyesis/genética , Regiones Promotoras GenéticasRESUMEN
Manganese is an essential yet potentially toxic metal. Initially reported in 2012, mutations in SLC30A10 are the first known inherited cause of manganese excess. SLC30A10 is an apical membrane protein that exports manganese from hepatocytes into bile and from enterocytes into the lumen of the gastrointestinal tract. SLC30A10 deficiency results in impaired gastrointestinal manganese excretion, leading to manganese excess, neurologic deficits, liver cirrhosis, polycythemia, and erythropoietin excess. Neurologic and liver disease are attributed to manganese toxicity. Polycythemia is attributed to erythropoietin excess. The goal of this study was to determine the basis of erythropoietin excess in SLC30A10 deficiency. Here, we demonstrate that transcription factors hypoxia-inducible factor 1a (Hif1a) and 2a (Hif2a), key mediators of the cellular response to hypoxia, are both upregulated in livers of Slc30a10-deficient mice. Hepatic Hif2a deficiency corrected erythropoietin expression and polycythemia and attenuated aberrant hepatic gene expression in Slc30a10-deficient mice, while hepatic Hif1a deficiency had no discernible impact. Hepatic Hif2a deficiency also attenuated manganese excess, though the underlying cause of this is not clear at this time. Overall, our results indicate that hepatic HIF2 is a key determinant of pathophysiology in SLC30A10 deficiency and expand our understanding of the contribution of HIFs to human disease.
Asunto(s)
Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Subunidad alfa del Factor 1 Inducible por Hipoxia , Hígado , Manganeso , Policitemia , Animales , Policitemia/metabolismo , Policitemia/genética , Ratones , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Hígado/metabolismo , Manganeso/metabolismo , Manganeso/toxicidad , Manganeso/deficiencia , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Humanos , Proteínas de Transporte de Catión/genética , Proteínas de Transporte de Catión/metabolismo , Eritropoyetina/metabolismo , Eritropoyetina/genética , Ratones Noqueados , Masculino , Hepatocitos/metabolismoRESUMEN
Customizable and number-tunable enzyme delivery nanocarriers will be useful in tumor therapy. Herein, a phage vehicle, T4-Lox-DNA-Fe (TLDF), which adeptly modulates enzyme numbers using phage display technology to remodel the tumor microenvironment (TME) is presented. Regarding the demand for lactic acid in tumors, each phage is engineered to display 720 lactate oxidase (Lox), contributing to the depletion of lactic acid to restructure the tumor's energy metabolism. The phage vehicle incorporated dextran iron (Fe) with Fenton reaction capabilities. H2O2 is generated through the Lox catalytic reaction, amplifying the H2O2 supply for dextran iron-based chemodynamic therapy (CDT). Drawing inspiration from the erythropoietin (EPO) biosynthetic process, an EPO enhancer is constructed to impart the EPO-Keap1 plasmid (DNA) with tumor hypoxia-activated functionality, disrupting the redox homeostasis of the TME. Lox consumes local oxygen, and positive feedback between the Lox and the plasmid promotes the expression of kelch ECH Associated Protein 1 (Keap1). Consequently, the downregulation of the antioxidant transcription factor Nrf2, in synergy with CDT, amplifies the oxidative killing effect, leading to tumor suppression of up to 78%. This study seamlessly integrates adaptable T4 phage vehicles with bio-intelligent plasmids, presenting a promising approach for tumor therapy.
Asunto(s)
Plásmidos , Microambiente Tumoral , Animales , Plásmidos/genética , Ratones , Humanos , Microambiente Tumoral/efectos de los fármacos , Neoplasias/terapia , Neoplasias/genética , Neoplasias/tratamiento farmacológico , Modelos Animales de Enfermedad , Eritropoyetina/genética , Oxigenasas de Función Mixta/genética , Oxigenasas de Función Mixta/metabolismo , Nanopartículas/química , Bacteriófagos/genética , Proteína 1 Asociada A ECH Tipo Kelch/genética , Proteína 1 Asociada A ECH Tipo Kelch/metabolismo , Línea Celular TumoralRESUMEN
OBJECTIVE: The aim of this study was to assess the efficacy and safety of a third-generation lentivirus-based vector encoding the feline erythropoietin (EPO) (feEPO) gene in vitro and in rodent models in vivo. This vector incorporates a genetic mechanism to facilitate the termination of the therapeutic effect in the event of supraphysiologic polycythemia, the herpes simplex virus thymidine kinase (HSV-TK) "suicide gene." ANIMALS: CFRK cells and replication-defective lentiviral vectors encoding feEPO were used for in vitro experiments. Eight Fischer rats were enrolled in the pilot in vivo study, 24 EPO-deficient mice were used in the initial mouse study, and 15 EPO-deficient mice were enrolled in the final mouse study. METHODS: Efficacy of a third-generation lentivirus encoding feEPO was determined in vitro using western blot assays. Subsequently, in a series of rodent experiments, animals were administered the viral vector in progressively increasing inoculation doses with serial measurements of blood packed cell volume (PCV) over time. RESULTS: We documented production of feEPO protein in transduced CRFK cells with subsequent cessation of production when treated with the HSV-TK substrate ganciclovir. In vivo, we demonstrated variably persistent elevated PCV values in treated rats and mice with eventual return to baseline values over time. CLINICAL RELEVANCE: These results provide justification for a lentiviral gene therapy approach to the treatment of nonregenerative anemia associated with chronic renal disease in cats.
Asunto(s)
Anemia , Eritropoyetina , Terapia Genética , Vectores Genéticos , Lentivirus , Ratas Endogámicas F344 , Animales , Eritropoyetina/genética , Terapia Genética/veterinaria , Lentivirus/genética , Ratones , Anemia/veterinaria , Anemia/terapia , Gatos , Ratas , Insuficiencia Renal Crónica/terapia , Insuficiencia Renal Crónica/veterinaria , Masculino , Femenino , Línea CelularRESUMEN
Gene doping involves the misuse of genetic materials to alter an athlete's performance, which is banned at all times in both human and equine sports. Quantitative polymerase chain reaction (qPCR) assays have been used to control the misuse of transgenes in equine sports. Our laboratory recently developed and implemented duplex as well as multiplex qPCR assays for transgenes detection. To further advance gene doping control, we have developed for the first time a sensitive and definitive PCR-liquid chromatography high-resolution tandem mass spectrometry (PCR-LC-HRMS/MS) method for transgene detection with an estimated limit of detection of below 100 copies/mL for the human erythropoietin (hEPO) transgene in equine plasma. The method involved magnetic-glass-particle-based extraction of DNA from equine plasma prior to PCR amplification with 2'-deoxyuridine 5'-triphosphate (dUTP) followed by treatments with uracil DNA glycosylase and hot piperidine for selective cleavage to give small oligonucleotide fragments. The resulting DNA fragments were then analyzed by LC-HRMS/MS. The applicability of this method has been demonstrated by the successful detection of hEPO transgene in a blood sample collected from a gelding (castrated male horse) that had been administered the transgene. This novel approach not only serves as a complementary method for transgene detection but also paves the way for developing a generic PCR-LC-HRMS/MS method for the detection of multiple transgenes.
Asunto(s)
Doping en los Deportes , Eritropoyetina , Caballos , Animales , Humanos , Masculino , Espectrometría de Masas en Tándem/métodos , Doping en los Deportes/prevención & control , Cromatografía Liquida/métodos , Eritropoyetina/genética , Transgenes , ADN , Reacción en Cadena de la PolimerasaRESUMEN
The term 'gene doping' is used to describe the use of any unauthorized gene therapy techniques. We developed a test for five likely candidate genes for equine gene doping: EPO, FST, GH1, IGF1, and ILRN1. The test is based on real-time polymerase chain reaction (PCR) and includes separate screening and confirmation assays that detect different unique targets in each transgene. For doping material, we used nonviral (plasmid) and viral (recombinant adeno-associated virus) vectors carrying complementary DNA for the targeted genes; the vectors were accurately quantified by digital PCR. To reduce non-specific amplification from genomic DNA observed in some assays, a restriction digest step was introduced in the PCR protocol prior to cycling to cut the amplifiable targets within the endogenous genes. We made the screening stage of the test simpler and faster by multiplexing PCR assays for four transgenes (EPO, FST, IGF1, and ILRN1), while the GH1 assay is performed in simplex. Both stages of the test reliably detect at least 20 copies of each transgene in a background of genomic DNA equivalent to what is extracted from two milliliters of equine blood. The test protocol was documented and tested with equine blood samples provided by an official doping control authority. The developed tests will form the basis for screening official horseracing samples in Australia.
Asunto(s)
Eritropoyetina , Animales , Caballos/genética , Eritropoyetina/genética , Australia , Plásmidos , ADN/genética , Reacción en Cadena en Tiempo Real de la PolimerasaRESUMEN
Janus kinase 2 (JAK2) mediates type I/II cytokine receptor signaling, but JAK2 is also activated by somatic mutations that cause hematological malignancies by mechanisms that are still incompletely understood. Quantitative superresolution microscopy (qSMLM) showed that erythropoietin receptor (EpoR) exists as monomers and dimerizes upon Epo stimulation or through the predominant JAK2 pseudokinase domain mutations (V617F, K539L, and R683S). Crystallographic analysis complemented by kinase activity analysis and atomic-level simulations revealed distinct pseudokinase dimer interfaces and activation mechanisms for the mutants: JAK V617F activity is driven by dimerization, K539L involves both increased receptor dimerization and kinase activity, and R683S prevents autoinhibition and increases catalytic activity and drives JAK2 equilibrium toward activation state through a wild-type dimer interface. Artificial intelligence-guided modeling and simulations revealed that the pseudokinase mutations cause differences in the pathogenic full-length JAK2 dimers, particularly in the FERM-SH2 domains. A detailed molecular understanding of mutation-driven JAK2 hyperactivation may enable novel therapeutic approaches to selectively target pathogenic JAK2 signaling.
Asunto(s)
Eritropoyetina , Janus Quinasa 2 , Inteligencia Artificial , Eritropoyetina/genética , Janus Quinasa 2/genética , Janus Quinasa 2/metabolismo , Mutación , Receptores de Eritropoyetina/genética , Transducción de Señal/genética , HumanosRESUMEN
Cellular and tissue adaptations to oxygen deprivation (hypoxia) are necessary for both normal physiology and disease. Responses to hypoxia are initiated by the cellular oxygen sensors prolyl-4-hydroxylase domain (PHD) proteins 1-3 and factor inhibiting HIF (FIH). These enzymes regulate the transcription factor hypoxia-inducible factor (HIF) in a hypoxia-sensitive manner. FIH also regulates proteins outside the HIF pathway, including the deubiquitinase OTUB1. Numerous preclinical analyses have demonstrated that treatment with HIF hydroxylase inhibitors is beneficial and protective in many hypoxia-associated diseases. However, clinically available HIF hydroxylase inhibitors increase erythropoietin (EPO) gene expression and red blood cell production, which can be detrimental in hypoxia-associated conditions, such as ischemia/reperfusion injury of the heart or chronic inflammation. Our understanding of the relevance of FIH in (patho)physiology is only in its infancy, but FIH activity does not govern erythropoietin expression. Therefore, it is of prime interest to assess the relevance of FIH activity in (patho)physiology in detail, as it may contribute to developing novel therapeutic options for treating hypoxia-associated diseases that do not affect Epo regulation. Here, we describe specific protocols for two different methods to assess FIH enzymatic activity within cells, using a HIF-dependent firefly luciferase-reporter gene and an oxomer-dependent assay. Oxomers are oxygen-dependent stable protein oligomers formed by FIH, for example, with the deubiquitinase OTUB1. Oxomer formation directly depends on FIH activity, providing a suitable cellular readout for an easy-to-use analysis of FIH enzymatic activity in cellulo. These techniques permit an analysis of FIH activity toward HIF and outside the HIF pathway, allowing the investigation of FIH activity under different (patho)physiological conditions and assessment of novel (putative) inhibitors.
Asunto(s)
Eritropoyetina , Humanos , Genes Reporteros , Eritropoyetina/genética , Oxigenasas de Función Mixta , Hipoxia , Oxígeno , Enzimas DesubicuitinizantesRESUMEN
The regulation of red blood cell (RBC) homeostasis is widely assumed to rely on the control of cell production by erythropoietin (EPO) and the destruction of cells at a fixed, species-specific age. In this work, we show that such a regulatory mechanism would be a poor homeostatic solution to satisfy the changing needs of the body. Effective homeostatic control would require RBC lifespan to be variable and tightly regulated. We suggest that EPO may control RBC lifespan by determining CD47 expression in newly formed RBCs and SIRP-α expression in sinusoidal macrophages. EPO could also regulate the initiation and intensity of anti-RBC autoimmune responses that curtail RBC lifespan in some circumstances. These mechanisms would continuously modulate the rate of RBC destruction depending on oxygen availability. The control of RBC lifespan by EPO and autoimmunity emerges as a key mechanism in the homeostasis of RBCs.
Asunto(s)
Eritropoyetina , Eritropoyetina/genética , Eritrocitos , Cognición , Homeostasis , LongevidadRESUMEN
Studies have highlighted the significant involvement of kidney pericytes in renal fibrosis. Kidney pericytes, classified as interstitial mesenchymal cells, are extensively branched, collagen-producing cells that closely interact with endothelial cells. This article aims to provide an overview of the recent advancements in understanding the physiological functions of pericytes and their roles in kidney diseases. In a healthy kidney, pericytes have essential physiological function in angiogenesis, erythropoietin (EPO) production, and the regulation of renal blood flow. Nevertheless, pericyte-myofibroblast transition has been identified as the primary cause of disease progression in acute kidney injury (AKI)-to-chronic kidney disease (CKD) continuum. Our recent research has demonstrated that hypoxia-inducible factor-2α (HIF-2α) regulates erythropoietin production in pericytes. However, this production is repressed by EPO gene hypermethylation and HIF-2α downregulation which were induced by transforming growth factor-ß1-activated DNA methyltransferase and activin receptor-like kinase-5 signaling pathway during renal fibrosis, respectively. Additionally, AKI induces epigenetic modifications in pericytes, rendering them more prone to extracellular matrix production, cell migration and proliferation, thereby contributing to subsequent capillary rarefaction and renal fibrosis. Further investigation into the specific functions and roles of different subpopulations of pericytes may contribute for the development of targeted therapies aimed at attenuating kidney disease and mitigating their adverse effects.