RESUMEN
Spermatozoa harbour a complex and environment-sensitive pool of small non-coding RNAs (sncRNAs)1, which influences offspring development and adult phenotypes1-7. Whether spermatozoa in the epididymis are directly susceptible to environmental cues is not fully understood8. Here we used two distinct paradigms of preconception acute high-fat diet to dissect epididymal versus testicular contributions to the sperm sncRNA pool and offspring health. We show that epididymal spermatozoa, but not developing germ cells, are sensitive to the environment and identify mitochondrial tRNAs (mt-tRNAs) and their fragments (mt-tsRNAs) as sperm-borne factors. In humans, mt-tsRNAs in spermatozoa correlate with body mass index, and paternal overweight at conception doubles offspring obesity risk and compromises metabolic health. Sperm sncRNA sequencing of mice mutant for genes involved in mitochondrial function, and metabolic phenotyping of their wild-type offspring, suggest that the upregulation of mt-tsRNAs is downstream of mitochondrial dysfunction. Single-embryo transcriptomics of genetically hybrid two-cell embryos demonstrated sperm-to-oocyte transfer of mt-tRNAs at fertilization and suggested their involvement in the control of early-embryo transcription. Our study supports the importance of paternal health at conception for offspring metabolism, shows that mt-tRNAs are diet-induced and sperm-borne and demonstrates, in a physiological setting, father-to-offspring transfer of sperm mitochondrial RNAs at fertilization.
Asunto(s)
Dieta Alta en Grasa , Epigénesis Genética , Mitocondrias , ARN Mitocondrial , Espermatozoides , Animales , Femenino , Humanos , Masculino , Ratones , Índice de Masa Corporal , Dieta Alta en Grasa/efectos adversos , Embrión de Mamíferos/citología , Embrión de Mamíferos/embriología , Embrión de Mamíferos/metabolismo , Epidídimo/citología , Epigénesis Genética/genética , Fertilización/genética , Perfilación de la Expresión Génica , Regulación del Desarrollo de la Expresión Génica , Ratones Endogámicos C57BL , Mitocondrias/genética , Mitocondrias/metabolismo , Mitocondrias/patología , Obesidad/genética , Obesidad/metabolismo , Obesidad/etiología , Oocitos/metabolismo , Sobrepeso/genética , Sobrepeso/metabolismo , Herencia Paterna/genética , ARN Mitocondrial/genética , ARN Mitocondrial/metabolismo , ARN Pequeño no Traducido/genética , ARN Pequeño no Traducido/metabolismo , ARN de Transferencia/genética , ARN de Transferencia/metabolismo , Espermatozoides/metabolismo , Testículo/citología , Transcripción GenéticaRESUMEN
Vulnerability of the fetus upon maternal obesity can potentially occur during all developmental phases. We aimed at elaborating longer-term health outcomes of fetal overnutrition during the earliest stages of development. We utilized Naval Medical Research Institute (NMRI) mice to induce pre-conceptional and gestational obesity and followed offspring outcomes in the absence of any postnatal obesogenic influences. Male adult offspring developed overweight, insulin resistance, hyperleptinemia, hyperuricemia and hepatic steatosis; all these features were not observed in females. Instead, they showed impaired fasting glucose and a reduced fat mass and adipocyte size. Influences of the interaction of maternal diet∗sex concerned offspring genes involved in fatty liver disease, lipid droplet size regulation and fat mass expansion. These data suggest that a peri-conceptional obesogenic exposure is sufficient to shape offspring gene expression patterns and health outcomes in a sex- and organ-specific manner, indicating varying developmental vulnerabilities between sexes towards metabolic disease in response to maternal overnutrition.
Asunto(s)
Dieta Alta en Grasa/efectos adversos , Susceptibilidad a Enfermedades/fisiopatología , Obesidad/fisiopatología , Adipocitos/metabolismo , Adipocitos/patología , Animales , Peso Corporal/fisiología , Tamaño de la Célula , Susceptibilidad a Enfermedades/etiología , Hígado Graso/etiología , Hígado Graso/fisiopatología , Femenino , Regulación del Desarrollo de la Expresión Génica , Prueba de Tolerancia a la Glucosa , Hiperuricemia/etiología , Hiperuricemia/fisiopatología , Resistencia a la Insulina/fisiología , Leptina/sangre , Masculino , Ratones Endogámicos , Obesidad/etiología , Obesidad/genética , Sobrepeso/etiología , Sobrepeso/fisiopatología , Embarazo , Efectos Tardíos de la Exposición Prenatal/etiología , Efectos Tardíos de la Exposición Prenatal/genética , Efectos Tardíos de la Exposición Prenatal/fisiopatología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores Sexuales , Grasa Subcutánea/metabolismo , Factores de TiempoRESUMEN
Betacellulin (BTC), a ligand of the epidermal growth factor receptor, has been shown to promote growth and differentiation of pancreatic beta-cells and to improve glucose metabolism in experimental diabetic rodent models. We employed transgenic mice (BTC-tg) to investigate the effects of long-term BTC overabundance on islet structure and glucose metabolism. Expression of BTC is increased in transgenic islets, which show normal structure and distribution of the different endocrine cell types, without pathological alterations. BTC-tg mice exhibit lower fasted glucose levels and improved glucose tolerance associated with increased glucose-induced insulin secretion. Surprisingly, quantitative stereological analyses revealed that, in spite of increased cell proliferation, the islet and beta-cell volumes were unchanged in BTC-tg mice, suggesting enhanced cell turnover. Insulin secretion in vitro was significantly higher in transgenic islets in medium containing high glucose (11.2 or 16.7mM) as compared to control islets. Our results demonstrate that long-term BTC overabundance does not alter pancreatic islet structure and beta-cell mass, but enhances glucose-induced insulin secretion in vivo as well as in vitro.
Asunto(s)
Glucosa/metabolismo , Insulina/metabolismo , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Islotes Pancreáticos/metabolismo , Animales , Apoptosis , Betacelulina , Proliferación Celular , Separación Celular , Glucosa/farmacología , Homeostasis , Secreción de Insulina , Islotes Pancreáticos/citología , Ratones , Ratones Transgénicos , TransgenesRESUMEN
The CALM/AF10 fusion gene is found in various hematological malignancies including acute myeloid leukemia (AML), T-cell acute lymphoblastic leukemia and malignant lymphoma. We have previously identified the leukemia stem cell (LSC) in a CALM/AF10-driven murine bone marrow transplant AML model as B220+ lymphoid cells with B-cell characteristics. To identify the target cell for leukemic transformation or 'cell of origin of leukemia' (COL) in non-disturbed steady-state hematopoiesis, we inserted the CALM/AF10 fusion gene preceded by a loxP-flanked transcriptional stop cassette into the Rosa26 locus. Vav-Cre-induced panhematopoietic expression of the CALM/AF10 fusion gene led to acute leukemia with a median latency of 12 months. Mice expressing CALM/AF10 in the B-lymphoid compartment using Mb1-Cre or CD19-Cre inducer lines did not develop leukemia. Leukemias had a predominantly myeloid phenotype but showed coexpression of the B-cell marker B220, and had clonal B-cell receptor rearrangements. Using whole-exome sequencing, we identified an average of two to three additional mutations per leukemia, including activating mutations in known oncogenes such as FLT3 and PTPN11. Our results show that the COL for CALM/AF10 leukemia is a stem or early progenitor cell and not a cell of B-cell lineage with a phenotype similar to that of the LSC in CALM/AF10+ leukemia.
Asunto(s)
Transformación Celular Neoplásica/patología , Leucemia Experimental/patología , Células Madre Neoplásicas/patología , Proteínas de Fusión Oncogénica/genética , Animales , Linfocitos B/metabolismo , Exoma/genética , Ingeniería Genética , Ratones , Mutación , Análisis de Secuencia de ADNRESUMEN
Only a small percentage of individuals develop posttraumatic stress disorder (PTSD) in the aftermath of a trauma. It is still largely unknown to what extent gene-environment interactions contribute to the inter-individual differences in PTSD susceptibility and resilience and what cellular processes may underlie long-term maintenance of the disorder. Here we employed a mouse model of PTSD to unravel the contribution of genetic background and maternal influences on long-lasting changes in kinase and transcription factor activities in PTSD-susceptible C57BL/6NCrl (B6N) and resilient C57BL/6JOlaHsd (B6JOla) mice. Mice received an inescapable foot shock and were tested for activity changes in the AKT/GSK-3beta/beta-catenin-pathway in specific brain structures 42 days later. To control for prenatal and postnatal environmental (i.e. maternal) factors part of the experiments were performed with animals originating from within-strain and between-strain embryo transfers. In PTSD-susceptible B6N mice, long-term maintenance of contextual and sensitized fear was accompanied by (i) increased levels of phosphorylated AKT within the dorsal hippocampus and (ii) higher levels of phosphorylated AKT and GSK-3beta and increased beta-catenin levels within the basolateral amygdala. In animals originating from embryo transfers, levels of phosphorylated GSK-3beta and of beta-catenin were decreased in the dorsal hippocampus, but increased in the basolateral amygdala of shocked B6N mice compared to shocked B6JOla mice. This was independent of the genotype of the recipient mothers. At the behavioural level, these differences coincided with sustained sensitized and more pronounced contextual fear of B6N compared to B6JOla mice. Taken together our study identifies lasting changes in the AKT/GSK-3beta/beta-catenin cascade within the hippocampus and amygdala as molecular correlates of genetically determined differences in the severity of PTSD-like symptoms.