Project description:Olfactory ensheathing cells are one of the few central nervous system regenerative cells discovered so far. It is characterized by its lifelong nerve regeneration function, and it can also release a variety of neurotrophic factors and neural adhesion molecules. It is considered to be the glial cell with the strongest myelination ability. Olfactory ensheathing cells and Schwann cells have phenotypes in common, they can promote axon regeneration(R. Doucette, 1995). Olfactory ensheathing cells have the characteristics of Schwann cells and astrocytes, but the overall performance tends to be the former, which has two unique characteristics. First, it exists not only in the peripheral nerves (Schwann cells), but also in the central nervous system (astroglia); second, the olfactory mucosa has the ability to regenerate life-long, including human olfactory ensheathing cells(J. C. Bartolomei and C. A. Greer, 2000). Regeneration is a process in which olfactory ensheathing cells participate in efficient regulation, although the specific mechanism is not yet clear. Olfactory ensheathing cells are different from astrocytes and Schwann cells, but at the same time have the characteristics of these two cells(S. C. Barnett, 2004), like Schwann cells help axon growth, but more than Schwann cells It can make axons grow long distances, that is, it has stronger migration(A. Ramon-Cueto et al., 1998); there are also astrocytes that have a nutritional effect on the survival of neurons and the growth of axons, but olfactory ensheathing cells can also wrap neurons forms myelin sheath to support the growth of nerve processes(R. Devon and R. Doucette, 1992; J. Gu et al., 2019). There are two characteristics that make olfactory ensheathing cells the best choice for the treatment of neurological diseases(S. C. Chiu et al., 2009; J. Kim et al., 2018; M. Abdel-Rahman et al., 2018). Olfactory ensheathing cells are gradually used to treat spinal cord injuries and have shown amazing effects(J. C. Bartolomei and C. A. Greer, 2000; K. J. Liu et al., 2010; R. Yao et al., 2018). Olfactory ensheathing cells that have been used in research are usually derived from the olfactory bulb(E. H. Franssen et al., 2007), but it is easier to obtain olfactory ensheathing cells from the olfactory mucosa in clinical practice(M. Ryszard et al., 2006), so the difference between the olfactory ensheathing cells from the olfactory bulb and the olfactory mucosa There are more and more studies(B. M. U. et al., 2007), and previous studies have shown that they not only have many similar functions, but also have many differences(M. W. Richter et al., 2005; L. Wang et al., 2014; K. E. Smith et al., 2020). Because olfactory ensheathing cells derived from the olfactory bulb are not easy to obtain, olfactory ensheathing cells derived from the olfactory mucosa have become the focus of attention. Although we know that olfactory ensheathing cells from two sources have nerve repair functions, it is not clear why the two different sources of olfactory ensheathing cells have different therapeutic effects. Nicolas G. once studied that the genetic difference between the two cells and found that there are many genes related to wound repair and nerve regeneration(G. Nicolas et al., 2010). We have reason to guess that olfactory ensheathing cells from these two sources will also have a large difference in protein level. Our research group wants to use the current mature transcriptome and proteomic sequencing technologies to explore the difference between olfactory ensheathing cells from the olfactory bulb and olfactory mucosa, and explain why the two sources of olfactory ensheathing cells shows different therapeutic effects, hope to provide a new theoretical basis for future clinical treatment.

Project description:Distant enhancer elements are a major source of specificity in mammalian gene expression. Although enhancers that regulate broad developmental decisions and inducible gene expression have been studied extensively, little is known about regulatory elements that govern monogenic and monoallelic expression. Here, using high throughput epigenetic and genetic techniques we identified a plethora of distant enhancers that regulate monoallelic olfactory receptor (OR) gene expression. Potential OR enhancers have unique, cell type specific epigenetic marks that distinguish them from other neuronal enhancers and correlate with enhancer activity in vivo. Using sequence capture to enrich for these sequences we identified Dnase-protected footprints that reveal novel regulatory sequences and transcription factors required for OR gene activation. Our experiments provide insight to the regulation of OR expression, and describe novel principles and methodologies towards the understanding of transcriptional mechanisms that generate cellular diversity. In vivo examination of H3K79me3 enrichment and DNAse protected footprints on olfactory receptor enhancer sequences. We performed ChIP-seq on native chromatin isolated from the mouse olfactory epithelium using antibodies against H3K79me3. To sequence accessible regions of the genome we treated nuclei with limiting amounts of DNAse I to digest accessible chromatin and perform Dnase Hypersensitivity (DHS)-seq. In the olfactory epithelium, the H enhancer – the first described enhancer for olfactory receptors has a well-defined DNAse I hypersensitivity peak and is flanked by high levels of H3K79me3. We find other intergenic sequences nearby olfactory receptor genes that share the same chromatin signature, and test their function in vivo. TO uncover transcription factor footprints on olfactory receptor enhancers we performed sequence capture of the DHS-seq library to enrich for these sequences. We find multiple DNAse-protected sequences and perform motif analysis on transcription factor footprints to reveal factors involved in olfactory receptor gene regulation.

Dataset Information

Olfactory

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure