RESUMEN
Mounting evidence in the literature suggests that RNA-RNA binding protein aggregations can disturb neuronal homeostasis and lead to symptoms associated with normal aging as well as dementia. The specific ablation of cyclin A2 in adult neurons results in neuronal polyribosome aggregations and learning and memory deficits. Detailed histologic and ultrastructural assays of aged mice revealed that post-mitotic hippocampal pyramidal neurons maintain cyclin A2 expression and that proliferative cells in the dentate subgranular zone express cyclin A2. Cyclin A2 loss early during neural development inhibited hippocampal development through canonical/cell-cycle mechanisms, including prolonged cell cycle timing in embryonic hippocampal progenitor cells. However, in mature neurons, cyclin A2 colocalized with dendritic rRNA. Cyclin A2 ablation in adult hippocampus resulted in decreased synaptic density in the hippocampus as well as in accumulation of rRNA granules in dendrite shafts. We conclude that cyclin A2 functions in a noncanonical/non-cell cycle regulatory role to maintain adult pyramidal neuron ribostasis.
Asunto(s)
Envejecimiento , Ciclina A2/deficiencia , Gránulos Citoplasmáticos , Hipocampo , Células Piramidales , ARN Ribosómico/metabolismo , Envejecimiento/genética , Envejecimiento/metabolismo , Envejecimiento/patología , Animales , Animales Modificados Genéticamente , Ciclo Celular , Ciclina A2/metabolismo , Gránulos Citoplasmáticos/genética , Gránulos Citoplasmáticos/metabolismo , Gránulos Citoplasmáticos/patología , Hipocampo/metabolismo , Hipocampo/patología , Ratones , Células Piramidales/metabolismo , Células Piramidales/patología , ARN Ribosómico/genética , Sinapsis/genética , Sinapsis/metabolismo , Sinapsis/patologíaRESUMEN
Alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV) is a rare and lethal developmental disorder of the lung defined by a constellation of characteristic histopathological features. Nonpulmonary anomalies involving organs of gastrointestinal, cardiovascular, and genitourinary systems have been identified in approximately 80% of patients with ACD/MPV. We have collected DNA and pathological samples from more than 90 infants with ACD/MPV and their family members. Since the publication of our initial report of four point mutations and 10 deletions, we have identified an additional 38 novel nonsynonymous mutations of FOXF1 (nine nonsense, seven frameshift, one inframe deletion, 20 missense, and one no stop). This report represents an up to date list of all known FOXF1 mutations to the best of our knowledge. Majority of the cases are sporadic. We report four familial cases of which three show maternal inheritance, consistent with paternal imprinting of the gene. Twenty five mutations (60%) are located within the putative DNA-binding domain, indicating its plausible role in FOXF1 function. Five mutations map to the second exon. We identified two additional genic and eight genomic deletions upstream to FOXF1. These results corroborate and extend our previous observations and further establish involvement of FOXF1 in ACD/MPV and lung organogenesis.
Asunto(s)
Factores de Transcripción Forkhead/genética , Factores de Transcripción Forkhead/metabolismo , Mutación , Síndrome de Circulación Fetal Persistente/genética , Síndrome de Circulación Fetal Persistente/metabolismo , Dominios y Motivos de Interacción de Proteínas/genética , Secuencia de Aminoácidos , Mapeo Cromosómico , Bases de Datos Genéticas , Femenino , Factores de Transcripción Forkhead/química , Dosificación de Gen , Orden Génico , Humanos , Lactante , Recién Nacido , Masculino , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Síndrome de Circulación Fetal Persistente/mortalidad , Síndrome de Circulación Fetal Persistente/patología , Alineación de SecuenciaRESUMEN
The emergence of systems neuroscience tools requires parallel generation of objective analytical workflows for experimental neuropathology. We developed an objective analytical workflow that we used to determine how specific autonomic neural lineages change during postnatal development. While a wealth of knowledge exists regarding postnatal alterations in respiratory neural function, how these neural circuits change and develop in the weeks following birth remains less clear. In this study, we developed our workflow by combining genetic mouse modeling and quantitative immunofluorescent confocal microscopy and used this to examine the postnatal development of neural circuits derived from the transcription factors NKX2.2 and OLIG3 into three medullary respiratory nuclei. Our automated FIJI-based image analysis workflow rapidly and objectively quantified synaptic puncta in user-defined anatomic regions. Using our objective workflow, we found that the density and estimated total number of Nkx2.2-derived afferents into the pre-Bötzinger Complex significantly decreased with postnatal age during the first three weeks of postnatal life. These data indicate that Nkx2.2-derived structures differentially influence pre-Bötzinger Complex respiratory oscillations at different stages of postnatal development.