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:PGCs undergo two distinct stages of demethylation before reaching a hypomethylated ground state at E13.5. Stage 1 occurs between E7.25- E9.5 in which PGCs experience a global loss of cytosine methylation. However, discreet loci escape this global loss of methylation and between E10.5-E13.5, stage 2 of demethylation takes place. In this stage these loci are targeted by Tet1 and Tet2 leading to the loss of the remaining methylation and resulting in the epigenetic ground state. Our data shows that Dnmt1 is responsible for maintaining the methylation of loci that escape stage 1 demethylation, and that it functions in a UHRF1 independent manner. Our data further demonstrates that when these loci lose methylation prior to stage 2 it results in early activation of the meiotic program, which leads to precocious differentiation of the germ line resulting in a decreased pool of PGCs in the embryo and subsequent infertility in adult mice.
Project description:We created mice, which are deficient for Myc specifically in cardiac myocytes by crossing crossed Myc-floxed mice (Mycfl/fl) and MLC-2VCre/+ mice. Serial analysis of earlier stages of gestation revealed that Myc-deficient mice died prematurely at E13.5-14.5. Morphological analyses of E13.5 Myc-null embryos showed normal ventricular size and structure; however, decreased cardiac myocyte proliferation and increased apoptosis was observed. BrdU incorporation rates were also decreased significantly in Myc-null myocardium. Myc-null mice displayed a 3.67-fold increase in apoptotic cardiomyocytes by TUNEL assay. We examined global gene expression using oligonucleotide microarrays. Numerous genes involved in mitochondrial death pathways were dysregulated including Bnip3L and Birc2. Keywords: wildtype vs Myc-null
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.