Gene expression profile associated with PTB-mediated transdifferentiation of human fibroblast cells into neurons
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ABSTRACT: Fibroblasts can be directly converted into neurons in vitro by depletion of nPTB, the reprogramming process induces neuronal gene expression while inhibits fibroblast gene expression. Human fibroblasts lacking CSB can not be converted into neurons, unless CSB gene was introduced. This study characterizes the CSB-dependent gene expression alterations during reprogramming. Using Nimblegen microarray we identified differentially expressed genes in induced neurons from wild type CSB reconstituted fibroblasts, and we proved that the difference in gene expression after reprogramming was not observed in CS1AN cells.
Project description:Direct conversion of somatic cells into neurons holds great promise for regenerative medicine. However, neuronal conversion is relatively inefficient in human cells compared to mouse cells. It has been unclear what might be the key barriers to reprogramming in human cells. We recently elucidated an RNA program mediated by the polypyrimidine tract binding protein PTB to convert mouse embryonic fibroblasts (MEFs) into functional neurons. In human adult fibroblasts (HAFs), however, we unexpectedly found that invoking the documented PTB–REST–miR-124 loop generates only immature neurons. We now report that the functionality requires sequential inactivation of PTB and the PTB paralog nPTB in HAFs. Inactivation of nPTB triggers another self-enforcing loop essential for neuronal maturation, which comprises nPTB, the transcription factor BRN2, and miR-9. These findings suggest that two separate gatekeepers control neuronal conversion and maturation and consecutively overcoming these gatekeepers enables deterministic reprogramming of HAFs into functional neurons.
Project description:Direct conversion of somatic cells into neurons holds great promise for regenerative medicine. However, neuronal conversion is relatively inefficient in human cells compared to mouse cells. It has been unclear what might be the key barriers to reprogramming in human cells. We recently elucidated an RNA program mediated by the polypyrimidine tract binding protein PTB to convert mouse embryonic fibroblasts (MEFs) into functional neurons. In human adult fibroblasts (HAFs), however, we unexpectedly found that invoking the documented PTB–REST–miR-124 loop generates only immature neurons. We now report that the functionality requires sequential inactivation of PTB and the PTB paralog nPTB in HAFs. Inactivation of nPTB triggers another self-enforcing loop essential for neuronal maturation, which comprises nPTB, the transcription factor BRN2, and miR-9. These findings suggest that two separate gatekeepers control neuronal conversion and maturation and consecutively overcoming these gatekeepers enables deterministic reprogramming of HAFs into functional neurons.
Project description:Human fibroblasts can be directly converted into cholinergic neurons by Neurogenin 2 (Neurog2 or NGN2) under the treatments of small molecules. Genome-wide analysis of gene expression was performed to examine the similarity of converted neurons to samples from human brain or spinal cord.
Project description:Human fibroblasts can be directly converted into cholinergic neurons by Neurogenin 2 (Neurog2 or NGN2) under the treatments of small molecules. Genome-wide analysis of gene expression was performed to examine the similarity of converted neurons to samples from human brain or spinal cord. Total RNA obtained from isolated human fetal lung fibroblasts or converted neurons at 21 days. Commercially available total RNAs from adult human brains and spinal cords were used as controls.
Project description:As the causative gene for cockayne syndrome, CSB has a well-characerized function in transcription-coupled nucleotide excision repair. However, the complex neurological abnormalities that affect CS patients can not be simply explained by the DNA repair defects. CSB is also involved in RNAP II transcription regulation. This study characterizes the gene expression signatures affected by CSB protein. Using Nimblegen microarray we identified differentially expressed genes in human fibroblasts derived from CS patients as compared to CSB reconstituted cell lines (wild type).
Project description:Recently, direct reprogramming between divergent lineages has been achieved by introducing cell-fate-determining transcription factors. This progress may provide alternative cell resources for drug discovery and regenerative medicine. However, the genetic manipulation may limit the future application of these approaches. In this study, we identified a novel small-molecule cocktail that directly converted fibroblasts into neuronal cell fate with a high yield up after 16-days of induction. After a further maturation stage, these chemically-induced neurons (CiNs) possessed neuron-specific expression patterns, generated action potentials and formed functional synapses. Gene expression profiling revealed the activation of neuronal specific genes in the early stage of small molecule treatment. Overall, our findings prove the principle of chemically-induced direct reprogramming of somatic cell fates across germ layers without genetic manipulation, and show that cell fate can be manipulated through disrupting initial cell program and activating target cell master genes with pure chemicals. Total of 15 samples were analyzed, including mouse fibroblasts, mouse cortical primary neurons and chemically-induced neurons by different duration of chemical induction (Day0, Day4, Day8, Day19) and different small-molecule cocktail (FICB, FICB-1)
Project description:Direct conversion from fibroblast to neuron has recently been successfully induced bypassing the pluripotent state. However, the conversion takes a few months with low percentages of success. Here we found that depletion of p53, which can converted fibroblasts into three major neural lineages: neurons, astrocytes and oligodendrocytes. Furthermore, our method provided a high efficiency of conversion in aging fibroblasts, where published methods failed. This finding may help developing a prototype for neuron replacement therapy, including foraging people vulnerable to neurological disorders. p53 has been shown to inhibit reprogramming of fibroblasts to iPS cells, by depletion of p53 in human fibroblasts, we study the function of p53 in induced neuron process. By induction of p53 knockdown fibroblasts with special neuron medium, we can get mature neurons directly. In the induction process, many neurogenic transcription factors were up-regulated, and we prove that p21 is not involved in this process.
Project description:A new ubiquitination site of CSB was identified and proved to play roles in oxidative stress repair. This study characterizes the gene expression signatures affected by CSB-K991R as compared to wild type and UBD mutant. Using Nimblegen microarray we identified differentially expressed genes in human fibroblasts derived from CS patients as compared to CSB reconstituted cell lines (wild type), also we found the similar gene expression patterns between K991R and UBD mutant derivatives.