A switch in numb isoforms is a critical step in cortical development

Loss of numb function suggests that numb maintains progenitors in an undifferentiated state. Herein, we demonstrate that numb1 and numb3 are expressed in undifferentiated cortical progenitors, whereas numb2 and numb4 become prominent throughout differentiation. To further assess the role of different numb isoforms in cortical neural development, we first created a Numb-null state with antisense morpholino, followed by the re-expression of specific numb isoforms. The re-expression of numb1 or numb3 resulted in a significant reduction of neural differentiation, correlating with an expansion of the cortical progenitor pool. In contrast, the expression of numb2 or numb4 resulted in a reduction of proliferating progenitors and a corresponding increase in mammalian achete-scute homologue (MASH1) expression, concurrent with the appearance of the microtubule[corrected]-associated [corrected] protein-2-positive neurons. Of interest, the effect of numb isoforms on neural differentiation could not be directly related to Notch, because classic canonical Notch signaling assays failed to uncover any differences in the four isoforms to inhibit the Notch downstream events. This finding suggests that numb may have other signaling properties during neuronal differentiation in addition to augmenting notch signal strengthNRC publication: Ye

Insulin acts as both a selective survival factor for cortical neural stem cells with myogenic potential and an instructive myogenic differentiation signal.

NRC publication: Ye

Pegylated interferon-α protects type 1 pneumocytes against SARS coronavirus infection in macaques

The primary cause of severe acute respiratory syndrome (SARS) is a newly discovered coronavirus. Replication of this SARS coronavirus (SCV) occurs mainly in the lower respiratory tract, and causes diffuse alveolar damage. Lack of understanding of the pathogenesis of SARS has prevented the rational development of a therapy against this disease. Here we show extensive SCV antigen expression in type 1 pneumocytes of experimentally infected cynomolgus macaques (Macaca fascicularis) at 4 d postinfection (d.p.i.), indicating that this cell type is the primary target for SCV infection early in the disease, and explaining the subsequent pulmonary damage. We also show that prophylactic treatment of SCV-infected macaques with the antiviral agent pegylated interferon-α (IFN-α) significantly reduces viral replication and excretion, viral antigen expression by type 1 pneumocytes and pulmonary damage, compared with untreated macaques. Postexposure treatment with pegylated IFN-α yielded intermediate results. We therefore suggest that pegylated IFN-α protects type 1 pneumocytes from SCV infection, and should be considered a candidate drug for SARS therapy.link_to_subscribed_fulltex