RESUMEN
Intravenous high-dose methotrexate (HD-MTX) is a critical chemotherapeutic agent in hematological malignancies, however, data are lacking on how to predict and prevent toxicities such as kidney injury. We retrospectively analyzed 539 episodes of HD-MTX (≥1 g/m2) delivered to 144 patients for treatment of prophylaxis of CNS hematological malignancy across three Australian institutions and correlated risk factors with toxicity. Clinically relevant (CTCAE v4.03 grade 2-4) nephrotoxicity occurred on 36 (7%) occasions and was mostly grade 2. Multivariate analysis revealed that doses ≥6 g/m2 (HR 5.02, 95%CI 1.46-17.2, p = 0.01) and interacting/nephrotoxic drugs (HR: 7.15, 91%CI: 2.18-23.512, p = 0.001) were the only factors associated with nephrotoxicity. 48-hour methotrexate level, hypoalbuminemia and increasing age were associated with prolonged clearance but not nephrotoxicity. Mucositis, liver dysfunction and cytopenias were transient and mild in most cases. We have demonstrated that the most common risk factors for nephrotoxicity are modifiable which may assist clinical decision-making when administering this important drug.
Asunto(s)
Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos , Neoplasias Hematológicas , Insuficiencia Renal , Australia/epidemiología , Neoplasias Hematológicas/tratamiento farmacológico , Humanos , Riñón , Metotrexato/uso terapéutico , Estudios RetrospectivosRESUMEN
In response to infection and injury, the neutrophil population rapidly expands and then quickly re-establishes the basal state when inflammation resolves. The exact pathways governing neutrophil/macrophage lineage outputs from a common granulocyte-macrophage progenitor are still not completely understood. From a forward genetic screen in zebrafish, we identify the transcriptional repressor, ZBTB11, as critical for basal and emergency granulopoiesis. ZBTB11 sits in a pathway directly downstream of master myeloid regulators including PU.1, and TP53 is one direct ZBTB11 transcriptional target. TP53 repression is dependent on ZBTB11 cys116, which is a functionally critical, metal ion-coordinating residue within a novel viral integrase-like zinc finger domain. To our knowledge, this is the first description of a function for this domain in a cellular protein. We demonstrate that the PU.1-ZBTB11-TP53 pathway is conserved from fish to mammals. Finally, Zbtb11 mutant rescue experiments point to a ZBTB11-regulated TP53 requirement in development of other organs.
Asunto(s)
Leucopoyesis/genética , Neutrófilos , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Represoras/genética , Transactivadores/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Proteínas de Pez Cebra/genética , Animales , Animales Modificados Genéticamente , Bases de Datos de Proteínas , Transducción de Señal , Pez Cebra , Dedos de ZincRESUMEN
We demonstrate that in zebrafish, the microRNA miR-451 plays a crucial role in promoting erythroid maturation, in part via its target transcript gata2. Zebrafish miR-144 and miR-451 are processed from a single precursor transcript selectively expressed in erythrocytes. In contrast to other hematopoietic mutants, the zebrafish mutant meunier (mnr) showed intact erythroid specification but diminished miR-144/451 expression. Although erythropoiesis initiated normally in mnr, erythrocyte maturation was morphologically retarded. Morpholino knockdown of miR-451 increased erythrocyte immaturity in wild-type embryos, and miR-451 RNA duplexes partially rescued erythroid maturation in mnr, demonstrating a requirement and role for miR-451 in erythrocyte maturation. mnr provided a selectively miR-144/451-deficient background, facilitating studies to discern miRNA function and validate candidate targets. Among computer-predicted miR-451 targets potentially mediating these biologic effects, the pro-stem cell transcription factor gata2 was an attractive candidate. In vivo reporter assays validated the predicted miR-451/gata2-3'UTR interaction, gata2 down-regulation was delayed in miR-451-knockdown and mnr embryos, and gata2 knockdown partially restored erythroid maturation in mnr, collectively confirming gata2 down-regulation as pivotal for miR-451-driven erythroid maturation. These studies define a new genetic pathway promoting erythroid maturation (mnr/miR-451/gata2) and provide a rare example of partial rescue of a mutant phenotype solely by miRNA overexpression.
Asunto(s)
Eritrocitos/citología , Células Eritroides/citología , Eritropoyesis/genética , Factor de Transcripción GATA2/genética , MicroARNs/genética , Proteínas de Pez Cebra/genética , Factores de Edad , Animales , Diferenciación Celular/fisiología , Regulación del Desarrollo de la Expresión Génica , Mutagénesis , Fenotipo , ARN Mensajero/metabolismo , Pez CebraRESUMEN
After a decade of the "modern era" of zebrafish hematology research, what have been their major contributions to hematology and what challenges does the model face? This review argues that, in hematology, zebrafish have demonstrated their suitability, are proving their utility, have supplied timely and novel discoveries, and are poised for further significant contributions. It presents an overview of the anatomy, physiology, and genetics of zebrafish hematopoiesis underpinning their use in hematology research. Whereas reverse genetic techniques enable functional studies of particular genes of interest, forward genetics remains zebrafish's particular strength. Mutants with diverse and interesting hematopoietic defects are emerging from multiple genetic screens. Some mutants model hereditary blood diseases, occasionally leading to disease genes first; others provide insights into developmental hematology. Models of malignant hematologic disorders provide tools for drug-target and pharmaceutics discovery. Numerous transgenic zebrafish with fluorescently marked blood cells enable live-cell imaging of inflammatory responses and host-pathogen interactions previously inaccessible to direct observation in vivo, revealing unexpected aspects of leukocyte behavior. Zebrafish disease models almost uniquely provide a basis for efficient whole animal chemical library screens for new therapeutics. Despite some limitations and challenges, their successes and discovery potential mean that zebrafish are here to stay in hematology research.