Delta‐like 4‐mediated Notch signaling is required for early T‐cell development in a three‐dimensional thymic structure

Delta‐like 4 (Dll4)‐mediated Notch signaling is critical for specifying T‐cell fate, but how Dll4‐mediated Notch signaling actually contributes to T‐cell development in the thymus remains unclear. To explore this mechanism in the thymic three‐dimensional structure, we performed fetal thymus organ culture using Dll4‐deficient mice. DN1a/b+DN2mt cells, which had not yet committed to either the αβ T or γδ T/NK cell lineage, did not differentiate into the αβ T‐cell lineage in Dll4‐deficient thymus despite the lack of cell fate conversion into other lineages. However, DN3 cells efficiently differentiated into a later developmental stage of αβ T cells, the double‐positive (DP) stage, although the proliferation was significantly impaired during the differentiation process. These findings suggest that the requirement for Notch signaling differs between the earliest and pre‐TCR‐bearing precursors and that continued Notch signaling is required for proper differentiation with active proliferation of αβ T lineage cells. Furthermore, we showed that Notch signaling increased the c‐Myc expression in DN3 cells in the thymus and that its overexpression rescued the proliferation and differentiation of DN3 cells in the Dll4‐null thymus. Therefore, c‐Myc plays a central role in the transition from stage DN3 to DP as a downstream target of Notch signaling.     

Notch1 modulates mesenchymal stem cells mediated regulatory T‐cell induction

Notch1 signaling is involved in regulatory T (Treg)‐cell differentiation. We previously demonstrated that, when cocultured with CD3⁺ cells, mesenchymal stem cells (MSCs) induced a T‐cell population with a regulatory phenotype. Here, we investigated the molecular mechanism underlying MSC induction of human Treg cells. We show that the Notch1 pathway is activated in CD4⁺ T cells cocultured with MSCs. Inhibition of Notch1 signaling through GSI‐I or the Notch1 neutralizing antibody reduced expression of HES1 (the Notch1 downstream target) and the percentage of MSC‐induced CD4⁺CD25^highFOXP3⁺ cells in vitro. Moreover, we demonstrate that FOXP3 is a downstream target of Notch signaling in human cells. No crosstalk between Notch1 and TGF‐β signaling pathways was observed in our experimental system. Together, these findings indicate that activation of the Notch1 pathway is a novel mechanism in the human Treg‐cell induction mediated by MSCs.     

人胚嗅球嗅鞘细胞原代培养的实验研究

目的拟建立人胚胎嗅球嗅鞘细胞的培养方法并探讨这些细胞在活性、纯度方面是否具备临床应用水平。方法用含有促进细胞生长的谷氨酰胺、转铁蛋白、生物素、硒酸纳的无血清纯化液纯化嗅鞘细胞,胰蛋白酶消化收集细胞,制成单细胞悬液。采用台盼蓝染色法进行活性测定,P75NGFR和S-100双标免疫荧光染色鉴定,以Hoechst复染鉴定OECs的纯度。结果可见比较典型的嗅鞘细胞:双极或梭形、多突起形和扁圆形,主要以梭形和多突起形细胞为主。细胞活性大于95%,纯度大于90%。结论实验建立的人胚胎嗅球嗅鞘细胞原代培养的方法可行,细胞活性大于95%,纯度和均一性已达到临床应用水平。     

Laser‐mediated cell ablation during post‐implantation mouse development

BACKGROUND: Laser‐mediated cell ablation is a powerful tool that has been used to understand cell fate in a variety of externally developing organisms but has not been used during mammalian post‐implantation development. RESULTS: We describe a method pairing laser ablation with murine embryo culture and establish parameters that can be used to precisely ablate cells in the selected field with minimal disruption to adjacent cells or the underlying cell matrix. Ablation of a large domain of endoderm, followed by ～1 day of culture results in a phenotypically normal embryo and gut tube, indicating that laser ablation is compatible with normal development. We next focused on one of the three precursor populations that have been shown to produce the liver bud. Ablations of a single progenitor domain result in a unilateral delay in the liver bud while the contralateral side is unaffected. CONCLUSIONS: We demonstrate that laser ablation is a specific and useful technique for studying cell fate in the mouse embryo. This method represents a powerful advance in developmental studies in the mouse and can be used to provide information on the specification of organs, differentiation, cell migration, and vital tissue interactions during development. Developmental Dynamics, 242:1202–1209, 2013. © 2013 Wiley Periodicals, Inc.     

A role for gangliosides and β1‐integrin in the motility of olfactory ensheathing glia

Olfactory ensheathing glia (OEG) are found in the olfactory mucosa, nerve and bulb, and provide in vivo ensheathment for the unmyelinated olfactory axons within the central and peripheral nervous system domains. OEG cells are able to migrate long distances within the neuropil of the central nervous system. Because gangliosides such as 9‐O‐acetyl GD3 have crucial regulatory roles in neuronal migration during development, we analyzed whether OEG in organotypical cultures are revealed by anti‐9‐O‐acetyl GD3 and/or gangliosides are recognized by the A2B5 antibody (G‐A2B5), and whether these gangliosides are involved in OEG migration. Our results showed that all OEG migrating out of a section of olfactory bulb onto a laminin substrate bound to the 9‐O‐acetyl GD3 and A2B5 antibodies, and that 2′,3′‐cyclic nucleotide phosphodiesterase (CNPase) colocalized with 9‐O‐acetyl GD3 and with G‐A2B5. Additionally, we showed that the immune blockade of 9‐O‐acetyl GD3 or G‐A2B5 reduced the migration of OEG on laminin, and that 9‐O‐acetyl GD3 and G‐A2B5 colocalized with the β1‐integrin subunit. We also confirmed the phenotype of in‐vitro‐grown OEG cells derived from adult rats, showing that they express CNPase, and also α‐smooth muscle actin, which is not expressed by Schwann cells. Our data showed that the gangliosides 9‐O‐acetyl GD3 and G‐A2B5 participate in the migratory activity of OEG cells, and that the β1‐integrin subunit colocalizes with these gangliosides. These results suggest a new role for β1‐integrin and gangliosides in the polarized migration of OEG cells, and provide new information on the molecules controlling OEG motility and behavior.     

Requirements for Jag1-Rbpj mediated Notch signaling during early mouse lens development

Background: During vertebrate lens development, the lens placode in the embryonic ectoderm invaginates into a lens vesicle, which then separates from the surface epithelium, followed by two waves of fiber cell differentiation. In the mouse, multiple labs have shown that Jag1‐Notch signaling is critically required during the second wave of lens fiber cell formation. However, Notch signaling appears to play no obvious role during lens induction or morphogenesis, although multiple pathway genes are expressed at these earlier stages. Results: Here, we explored functions for Notch signaling specifically during early lens development, by using the early‐acting AP2α‐Cre driver to delete Jag1 or Rbpj. We found that Jag1 and Rbpj are not required during lens induction, but are necessary for proper lens vesicle separation from the surface ectoderm. Conclusions: We conclude that precise levels of Notch signaling are essential during lens vesicle morphogenesis. In addition, AP2α‐Cre‐mediated deletion of Rbpj resulted in embryos with cardiac outflow tract and liver deformities, and perinatal lethality. Developmental Dynamics 241:493–504, 2012. © 2012 Wiley Periodicals, Inc.     

Notch1 is an important mediator for enhancing of B‐cell activation and antibody secretion by Notch ligand

The roles of Notch1 and Notch2 in T‐cell function have been well studied, but the functional roles of Notch in B cells have not been extensively investigated, except for Notch2 involvement in peripheral marginal zone B‐cell differentiation. This study examined the roles of Notch1 in murine primary B cells. During B‐cell activation by B‐cell receptor ligation, Notch1 was up‐regulated while Notch2 was not. In addition, Notch1 up‐regulation itself did not contribute to the further activation of B cells, but the Notch ligand was important for Notch1‐mediated further B‐cell activation. Moreover, Notch1 deficiency significantly decreased B‐cell activation and antibody secretion under the presence of Notch ligand. These data suggest that Notch1 is an important mediator for enhancing B‐cell activation and antibody secretion by Notch ligand.     

Activation of the Wnt/β‐catenin signaling reporter in developing mouse olfactory nerve layer marks a specialized subgroup of olfactory ensheathing cells

Wnt reporter TOPgal mice carry a β‐galactosidase (βgal) gene under the control of the Wnt/β‐catenin signaling responsive elements. We found that the intensely immunolabeled βgal⁺ cells were co‐immunolabeled with Nestin and formed a tangentially oriented single‐cell layer in the “connecting or docking zone” where the olfactory sensory axons attached to the brain surface during mid‐gestation. During early postnatal development, βgal⁺ cells were located in the inner olfactory nerve layer (ONLi) and co‐labeled with olfactory ensheathing cell (OEC) markers S100β and NPY but not with lineage‐specific markers for neurons, oligodendrocytes, astrocytes, and microglia, demonstrating that the TOPgal marked a subpopulation of OECs. By confocal microscopy, we found that TOPgal activated processes extended along the developing glomerulus and formed multiple tunnel‐like structures that ensheathe and bridge olfactory sensory axonal bundles from ONLi to the glomerulus, which may play a key role in glomerulus formation and convergent sorting of the peripheral olfactory axons. Developmental Dynamics 237:3157–3168, 2008. © 2008 Wiley‐Liss, Inc.     

Murine Notch1 is required for lymphatic vascular morphogenesis during development

BACKGROUND: The transmembrane receptor Notch1 is a critical regulator of arterial differentiation and blood vessel sprouting. Recent evidence shows that functional blockade of Notch1 and its ligand, Dll4, leads to postnatal lymphatic defects in mice. However, the precise role of the Notch signaling pathway in lymphatic vessel development has yet to be defined. Here we show the developmental role of Notch1 in lymphatic vascular morphogenesis by analyzing lymphatic endothelial cell (LEC)‐specific conditional Notch1 knockout mice crossed with an inducible Prox1CreER^T2 driver. RESULTS: LEC‐specific Notch1 mutant embryos exhibited enlarged lymphatic vessels. The phenotype of lymphatic overgrowth accords with increased LEC sprouting from the lymph sacs and increased filopodia formation. Furthermore, cell death was significantly reduced in Notch1‐mutant LECs, whereas proliferation was increased. RNA‐seq analysis revealed that expression of cytokine/chemokine signaling molecules was upregulated in Notch1‐mutant LECs isolated from E15.5 dorsal skin, whereas VEGFR3, VEGFR2, VEGFC, and Gja4 (Connexin 37) were downregulated. CONCLUSIONS: The lymphatic phenotype of LEC‐specific conditional Notch1 mouse mutants indicates that Notch activity in LECs controls lymphatic sprouting and growth during development. These results provide evidence that similar to postnatal and pathological lymphatic vessel formation, the Notch signaling pathway plays a role in inhibiting developmental lymphangiogenesis. Developmental Dynamics 243:957–964, 2014. © 2014 Wiley Periodicals, Inc.     

Mechanisms of ligand‐mediated inhibition in Notch signaling activity in Drosophila

The transmembrane proteins Delta and Serrate act as ligands for the signaling receptor Notch. In addition to this activating role, Delta and Serrate can also inhibit Notch signaling activity. This inhibitory effect is concentration‐dependent and appears to be evolutionarily conserved. In characterizing the underlying cellular mechanisms of the ligand inhibitory effect, we can confirm that ligand‐mediated inhibition of Notch signaling can occur as a cell autonomous process (cis‐inhibition) and that ligand‐mediated inhibition prevents a step in Notch signaling activation early enough to suppress Notch ectodomain shedding. Developmental Dynamics 239:798–805, 2010. © 2010 Wiley‐Liss, Inc.     

Epithelial oestrogen receptor α is dispensable for the development of oestrogen‐induced cervical neoplastic diseases

Human papillomavirus (HPV) is required but not sufficient for cervical carcinoma (CxCa) development. Oestradiol (E₂) promotes CxCa development in K14E7 transgenic mice expressing the HPV16 E7 oncoprotein under the control of the keratin (K14) promoter. E₂ mainly functions through oestrogen receptor α (ERα). However, the role of ERα in human CxCa has been underappreciated largely because it is not expressed in carcinoma cells. We have shown that deletion of Esr1 (the ERα‐coding gene) in the cervical stroma of K14E7 mice promotes regression of cervical intraepithelial neoplasia (CIN), the precursor lesion of CxCa. Here, we deleted Esr1 in the cervical epithelium but not in the stroma. We found that E₂ induced cervical epithelial cell proliferation in epithelial ERα‐deficient mice. We also found that E₂ promoted the development of CIN and CxCa in epithelial ERα‐deficient K14E7 mice and that all neoplastic epithelial cells were negative for ERα. In addition, proliferation indices were similar between ERα^– and ERα⁺ CxCa. These results indicate that epithelial ERα is not necessary for E₂‐induced CIN and CxCa. Taking these findings together, we conclude that stromal ERα rather than epithelial ERα mediates oncogenic E₂ signalling in CxCa. Our results support stromal ERα signalling as a therapeutic target for the disease. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Infusion of ex‐vivo expanded human TCR‐αβ+ double‐negative regulatory T cells delays onset of xenogeneic graft‐versus‐host disease

Despite the demonstration of potent immunosuppressive function of T cell receptor (TCR)‐αβ⁺ double‐negative regulatory T cells (DN T_regs), scarce numbers and lack of effective expansion method limit their clinical applications. Here we describe an approach that allows for ～3500‐fold ex‐vivo expansion of human DN T_regs within 3 weeks with > 97% purity. Ex‐vivo‐expanded DN T_regs suppress proliferation of polyclonally stimulated autologous T and B cells in vitro through direct cell‐to‐cell contact. In vivo, we demonstrate for the first time that infusion of human DN T_regs delayed an onset of xenogeneic graft‐versus‐host disease (GVHD) significantly in a humanized mouse model. Furthermore, preincubation of ex‐vivo‐expanded DN T_regs with a mechanistic target of rapamycin (mTOR) inhibitor rapamycin enhanced their immune regulatory function further. Taken together, this study demonstrates that human DN T_regs can be expanded ex vivo to therapeutic numbers. The expanded DN T_regs can suppress proliferation of T and B cells and attenuate GVHD, highlighting the potential clinical use of DN T_regs to mitigate GVHD.     

Analysis of gene expression in wild‐type and Notch1 mutant retinal cells by single cell profiling

Results: To examine the molecular underpinnings of this observation, microarray analysis of single retinal cells from wild‐type or Notch1 conditional knockout retinas was performed. In situ hybridization was carried out to validate some of the findings. 相似文献   

嗅鞘细胞移植治疗慢性脊髓损伤的临床研究进展

背景：虽然迄今为止大量的体外和动物实验都证实了嗅鞘细胞对脊髓损伤的修复作用,但是利用嗅鞘细胞移植治疗脊髓损伤的临床试验尚处于起步阶段。 目的：观察嗅鞘细胞移植治疗慢性脊髓损伤的临床安全性、有效性及实用性。 方法：由第一作者检索至2012年5月为止 PubMed数据及CNKI中国期刊全文数据库有关嗅鞘细胞移植治疗慢性脊髓损伤的临床试验研究及安全性、疗效方面相关的报道,以“olfactory ensheathing cells, spinal cord injury, clinical research”为英文检索词,“嗅鞘细胞移植,脊髓损伤”为中文检索词。 结果与结论：计算机初检得到133篇文献,阅读标题和摘要进行初筛,排除重复性研究,共34篇文献符合纳入标准。结果显示,利用嗅鞘细胞移植治疗脊髓损伤,在体外试验和动物模型中获得了良好的效果。在临床试验方面,到目前为止,嗅鞘细胞病灶直接移植治疗慢性脊髓损伤按嗅鞘细胞来源分主要集中在以下几个方面：①胚胎嗅鞘细胞移植。②嗅黏膜移植。③嗅黏膜源性嗅鞘细胞移植。3种嗅鞘细胞移植方法的总体安全性(96.4%)和有效性(23.4%)较高,但是其移植方法均存在明显的不足。提示嗅鞘细胞移植治疗慢性脊髓损伤的安全性和有效性还需要进一步验证,转化为临床应用还有很长的路要走。     

Liver sinusoidal endothelial cells induce immunosuppressive IL‐10‐producing Th1 cells via the Notch pathway

Under homeostasis, liver sinusoidal endothelial cells (LSECs) shift intrahepatic T‐cell responses towards tolerance. However, the role of LSECs in the regulation of T‐cell‐induced liver inflammation is less clear. Here, we studied the capacity of LSECs to modulate pro‐inflammatory Th1‐cell differentiation in mice. Using in vitro co‐culture systems and subsequent cytokine analysis, we showed that LSECs induced high amounts of the anti‐inflammatory cytokine IL‐10 in developing Th1 cells. These LSEC‐stimulated Th1 cells had no pro‐inflammatory capacity in vivo but instead actively suppressed an inflammatory Th1‐cell‐induced delayed‐type hypersensitivity reaction. Blockage of IL‐10 signaling in vivo inhibited immunosuppressive activity of LSEC‐stimulated Th1 cells. We identified the Notch pathway as a mechanism how LSECs trigger IL‐10 expression in Th1 cells. LSECs expressed high levels of the Delta‐like and Jagged family of Notch ligands and induced expression of the Notch target genes hes‐1 and deltex‐1 in Th1 cells. Blockade of Notch signaling selectively inhibited IL‐10 induction in Th1 cells by LSECs. Our findings suggest that LSEC‐induced IL‐10 expression in Th1 cells via the Notch pathway may contribute to the control of hepatic inflammatory immune responses by induction of a self‐regulatory mechanism in pro‐inflammatory Th1 cells.