RESUMO
The five vestibular organs of the inner ear derive from patches of prosensory cells that express the transcription factor SOX2 and the Notch ligand JAG1. Previous work suggests that JAG1-mediated Notch signaling is both necessary and sufficient for prosensory formation and that the separation of developing prosensory patches is regulated by LMX1a, which antagonizes Notch signaling. We used an inner ear-specific deletion of the Rbpjκ gene in which Notch signaling is progressively lost from the inner ear to show that Notch signaling, is continuously required for the maintenance of prosensory fate. Loss of Notch signaling in prosensory patches causes them to shrink and ultimately disappear. We show this loss of prosensory fate is not due to cell death, but rather to the conversion of prosensory tissue into non-sensory tissue that expresses LMX1a. Notch signaling is therefore likely to stabilize, rather than induce prosensory fate.
Assuntos
Orelha Interna/embriologia , Proteína Jagged-1/metabolismo , Receptores Notch/metabolismo , Animais , Proteínas de Ligação ao Cálcio/metabolismo , Diferenciação Celular , Orelha Interna/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/genética , Células Ciliadas Auditivas Internas/citologia , Proteína Jagged-1/genética , Proteínas com Homeodomínio LIM/metabolismo , Masculino , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos ICR , Organogênese/fisiologia , Receptores Notch/fisiologia , Fatores de Transcrição SOXB1/genética , Fatores de Transcrição SOXB1/metabolismo , Transdução de Sinais , Fatores de Transcrição/metabolismoRESUMO
Rotavirus causes severe diarrheal disease in children by broadly dysregulating intestinal homeostasis. However, the underlying mechanism(s) of rotavirus-induced dysregulation remains unclear. We found that rotavirus-infected cells produce paracrine signals that manifested as intercellular calcium waves (ICWs), observed in cell lines and human intestinal enteroids. Rotavirus ICWs were caused by the release of extracellular adenosine 5'-diphosphate (ADP) that activated P2Y1 purinergic receptors on neighboring cells. ICWs were blocked by P2Y1 antagonists or CRISPR-Cas9 knockout of the P2Y1 receptor. Blocking the ADP signal reduced rotavirus replication, inhibited rotavirus-induced serotonin release and fluid secretion, and reduced diarrhea severity in neonatal mice. Thus, rotavirus exploited paracrine purinergic signaling to generate ICWs that amplified the dysregulation of host cells and altered gastrointestinal physiology to cause diarrhea.