Epigenetic regulations on the maintenance of neural stem cells (NSCs) are complicated and far from been fully understood. Our previous findings have shown that after blocking Notch signaling in NSCs in vivo, the stemness of NSCs decreases, accompanied by the downregulated expression of miR-582-5p. In the current study, we further investigated the function and mechanism of miR-582-5p in the maintenance of NSCs in vitro and in vivo. After transfecting a mimic of miR-582-5p, the formation of neurospheres and proliferation of NSCs and intermediate progenitor cells (NS/PCs) were enhanced, and the expression of stemness markers such as Sox2, Nestin, and Pax6 also increased. The results were reversed after transfection of an inhibitor of miR-582-5p. We further generated miR-582 knock-out (KO) mice to investigate its function in vivo, and we found that the number of NSCs in the subventricular zone (SVZ) region decreased and the number of neuroblasts increased in miR-582 deficient mice, indicating reduced stemness and enhanced neurogenesis of NSCs. Moreover, RNA-sequencing and molecular biological analysis revealed that miR-582-5p regulates the stemness and proliferation of NSCs by inhibiting secretory protein FAM19A1. In summary, our research uncovered a new epigenetic mechanism that regulates the maintenance of NSCs, therefore providing novel targets to amplify NSCs in vitro and to promote neurogenesis in vivo during brain pathology and aging.
Copyright © 2022 Zhang, Li, Cao, Ji, Gao, Gao, Han, Yu and Zheng.

The examination of tissue histology by light microscopy is a fundamental tool for investigating the structure and function of organs under normal and disease states. Many current techniques for tissue sectioning, imaging and analysis are time-consuming, and they present major limitations for 3D tissue reconstruction. The introduction of methods to achieve the optical clearing and subsequent light-sheet laser scanning of entire transparent organs without sectioning represents a major advance in the field. We recently developed a highly reproducible and versatile clearing procedure called 3D imaging of solvent-cleared organs, or 3DISCO, which is applicable to diverse tissues including brain, spinal cord, immune organs and tumors. Here we describe a detailed protocol for performing 3DISCO and present its application to various microscopy techniques, including example results from various mouse tissues. The tissue clearing takes as little as 3 h, and imaging can be completed in ∼45 min. 3DISCO is a powerful technique that offers 3D histological views of tissues in a fraction of the time and labor required to complete standard histology studies.

The central event in thymic selection of T cells bearing alpha beta TCRs is their interaction with self-peptides bound to self-MHC molecules. With the use of transgenic mouse lines expressing a single peptide/MHC class II complex, we show that CD4+ T cells with the preferential usage of particular TCR V(alpha)s and V(beta)s were selected to mature on this complex in lines with the lower expression, whereas such CD4+ T cells were eliminated in the thymus in a line with the relatively high expression. When a low expressing line was crossed with a high expressing line, the frequency of CD4+ T cells selected by this complex markedly decreased. Thus, these results suggest that a single peptide/MHC class II complex, being affected by its cell surface density in the thymus, can serve as both positively and negatively selecting ligand in vivo.