Project description:The neuroectoderm is patterned along a rostral-caudal axis in response to localized factors in the embryo, but exactly how these factors act as positional information for this patterning is not yet fully understood. Here, using the self-organizing properties of mouse embryonic stem cell (ESC), we report that ESC-derived neuroectoderm self-generates a Six3+ rostral and a Irx3+ caudal bipolarized patterning. In this instance, localized Fgf signaling performs dual roles, as it regulates Six3+ rostral polarization at an earlier stage and promotes Wnt signaling at a later stage. The Wnt signaling components are differentially expressed in the polarized tissues, leading to genome-wide Irx3+ caudal-polarization signals. Surprisingly, differentially expressed Wnt agonists and antagonists have essential roles in orchestrating the formation of a balanced rostral-caudal neuroectoderm pattern. Together, our findings provide key processes for dynamic self-patterning and evidence that a temporally and locally regulated interaction between Fgf and Wnt signaling controls self-patterning in ESC-derived neuroectoderm.
Project description:Ventral midbrain (VM) dopaminergic progenitor cells derived from human pluripotent stem cells have the potential to replace endogenously lost dopamine neurons and are currently in preclinical and clinical development for treatment of Parkinson’s Disease (PD). However, one main challenge in the quality control of the cells is that rostral and caudal VM progenitors are extremely similar transcriptionally though only the caudal VM cells give rise to dopaminergic neurons with functionality in PD. Therefore, it is critical to develop assays which can rapidly and reliably discriminate rostral from caudal VM cells during clinical manufacturing. Here, we applied shotgun proteomics to search for novel secreted biomarkers specific for caudal VM progenitors compared to rostral VM progenitors and validated key hits by ELISA. From this, we identified novel secreted markers (CPE, LGI1 and PDGFC) significantly enriched in caudal versus rostral VM progenitor cultures, whereas the markers CNTN2 and CORIN were significantly enriched in rostral VM cultures. With this data, we suggest and test in clinical grade samples a panel of coupled ELISA assays that can be applied as a quality control tool for assessing the correct patterning of cells during clinical manufacturing.
Project description:NPCs adhesion affinity along the AP axis is under the control of Wnt/RA molecular networks Caudal NPCs express a high amount of ECM genes compare to rostral-NPCs.
Project description:Vertebrate limbs develop by integrating signals that control patterning along three main orthogonal axes. Flank-produced retinoic acid (RA) is initially required for limb induction and establishment of the apical ectodermal ridge (AER), a distal signaling center that produces fibroblast growth factors (FGFs), which are essential for limb growth and distalization. Once the AER is established, RA:FGF antagonism determines the restricted expression of a set of genes that control limb proximodistal patterning. Essential for this antagonism is the activation by FGF of the RA-degrading enzyme CYP26B1 in the distal limb bud. In addition, sonic hedgehog produced from the zone of polarizing activity (ZPA) is essential for distal limb anteroposterior patterning and contributes to RA reduction by cooperating in CYP26B1 activation. Meis transcription factors are expressed in the proximal limb bud, are activated by RA and can regulate proximodistal limb development; however, the mechanisms underlying their activity remain unknown. Here we studied Meis function in the mouse limb bud through Meis2 conditional overexpression and elimination of Meis1 and Meis2. We found that Meis activity is first required for limb bud initiation and the proper establishment of the AER and ZPA signaling centers, and subsequently for the development of proximal limb structures. Functional genomic analyses reveal that Meis is an important conveyor of the RA:FGF antagonism through the regulation of components of the RA and FGF signaling pathways, including CYP26B1. In addition, Meis regulates a set of proximal limb genes controlling proximodistal patterning and differentiation. Our work reveals a regulatory module essential for limb patterning and potentially co-opted in other patterning processes involving RA:FGF antagonism.
Project description:The spinal cord is generated progressively as cells leave the caudal region of the elongating body axis such that the temporal steps of neural differentiation become spatially separated along the head to tail axis. At key stages, it is therefore possible to isolate near-adjacent cell populations from the same embryo in distinct differentiation states. Cells in the caudal lateral epiblast adjacent to the primitive streak (also known as the stem zone, SZ, in the chick) express both early neural and mesodermal genes. Other cells in the stem zone will gastrulate to form the paraxial mesoderm or remain in the epiblast cell sheet and become neural progenitors. These latter cells form a new region called the preneural tube (PNT), which is flanked by unsegmented presomitic mesoderm and represents an early neural progenitor state that can be induced by FGF signalling to revert back to a multi-potent SZ state. Rostral to this, the closed caudal neural tube (CNT) is flanked by somites and is an early site of co-expression of genes characteristic of neural progenitors, and of ventral patterning genes (Diez del Corral et al., 2003). The CNT contains the first few neurons and exposure to FGF cannot revert this tissue to a multi-potent SZ state (Diez del Corral et al., 2002). The transition from the PNT to the CNT thus involves commitment to a neural fate that this is regulated by a switch from FGF to retinoid signalling. More advanced neuroepithelium is then located in more rostral neural tube (RNT), in which neuronal differentiation is ongoing and dorsoventral pattern is refined. This experiment uses the Affymetrix GeneChip chicken genome microarray to compare the transcriptomes of microdissections of these spatially distinct cell populations from the elongating neural axis of HH stage 10 chick embryos. Dissections were carried out in L15 medium at 4°C and explants pooled in TRIzol reagent (Gibco) for RNA extraction. Notochord was removed by controlled trypsin digestion that aimed to keep the neural ventral midline. For the microarrays, at least five tissue samples for each region were pooled to make each of three biological replicates for each (n>15 for each region).
Project description:We analyzed scRNA-seq data in human pluripotent stem cells derived neural tube models. This in vitro system recapitulates some key aspects of neural patterning in the entire neural tube, including both brain and SC regions, along both rostral-caudal and dorsal-ventral axes
Project description:NSCs adhesion affinity along the AP axis is under the control of endogenous signalling molecular networks, the Wnt and RA signalling The caudal spinal cord domain expresses a high amount of ECM genes compare to rostral.
Project description:The 5HT system is organized into rostral and caudal populations with discrete anatomical locations and opposite axonal trajectories in the developing hindbrain. 5HT neuron cell bodies in the rostral subdivision migrate to the midbrain and pons and extend ascending projections throughout the forebrain. 5HT cell bodies in the caudal subdivision migrate to the ventral medulla and caudal half of the pons and provide descending projections to the brainstem and spinal cord. Experiment Overall Design: We used microarrays to determine genes expressed by both rostral and caudal 5HT neurons as well as genes that are differentially expressed between rostral and caudal 5HT neurons at E12.5 when axon pathfinding and cell migration are underway. E12.5 neural tubes were isolated from ePet-EYFP embryos and dissected into a rostral domain (mesecephalic flexure to pontine flexure) and a caudal domain (pontine flexure to spinal cord). After cell dissociation (details under growth protocol), cells were subjected to fluorescent activated cell sorting (FACS) to obtain 4 cell populations. R+ = rostral ePetEYFP positive 5HT neurons; R- = YFP negative non-serotonergic cells in the rostral neural tube; C+ = caudal ePetEYFP positive 5HT neurons; C- = YFP negative non-serotonergic cells in the caudal neural tube. 200,000 cells for each of the 4 cell types (R+, R-, C+, C-) were collected for RNA extraction and hybridization to Affymetrix Mouse 430 2.0 arrays.
Project description:Our data show that Wnt and FGF signalling, and the downstream transcription factors NKX2.1 and TFAP2C, promote human alveolar or airway fate respectively. Moreover, we have functionally validated cell-cell interactions in human lung alveolar patterning. We show that Wnt signalling from differentiating fibroblasts promotes alveolar type 2 cell identity, whereas myofibroblasts secrete the Wnt inhibitor, NOTUM, providing spatial patterning. Our organoid system recapitulates key aspects of human lung development allowing mechanistic experiments to determine the underpinning molecular regulation.
Project description:The 5HT system is organized into rostral and caudal populations with discrete anatomical locations and opposite axonal trajectories in the developing hindbrain. 5HT neuron cell bodies in the rostral subdivision migrate to the midbrain and pons and extend ascending projections throughout the forebrain. 5HT cell bodies in the caudal subdivision migrate to the ventral medulla and caudal half of the pons and provide descending projections to the brainstem and spinal cord.