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dc.contributor.advisorJeanne B. Lawrence
dc.contributor.authorCzerminski, Jan T.
dc.date2022-08-11T08:08:38.000
dc.date.accessioned2022-08-23T16:02:04Z
dc.date.available2022-08-23T16:02:04Z
dc.date.issued2019-07-11
dc.date.submitted2019-07-31
dc.identifier.doi10.13028/j7xf-1q21
dc.identifier.urihttp://hdl.handle.net/20.500.14038/31257
dc.description.abstractDue to their underlying genetic complexity, chromosomal disorders such as Down syndrome (DS), which is caused by trisomy 21, have long been understudied and continue to lack effective treatments. With over 200 genes on the extra chromosome, even the specific cell pathologies and pathways impacted in DS are not known, and it has not been considered a viable target for the burgeoning field of gene therapy. Recently, our lab demonstrated that the natural mechanism of dosage compensation can be harnessed to silence the trisomic chromosome in pluripotent cells. Using an inducible XIST transgene allows us to study the effects of trisomy in a tightly controlled system by comparing the same cells with either two or three active copies of chromosome 21. In addition, it raises the prospect that insertion of a single gene into a trisomic chromosome could potentially be developed in the future for “chromosome therapy”. This thesis aims to utilize this inducible system for dosage compensation to study the neurodevelopmental effects of trisomy 21 in vitro, and to answer basic epigenetic questions critical to the viability of chromosome silencing as a therapeutic approach. Foremost, for XIST to have any prospect as a therapeutic, and to strengthen its experimental utility, it must be able to initiate chromosome silencing beyond its natural context of pluripotency. Here I demonstrate that, contrary to the current literature, XIST is capable of initiating chromosome silencing in differentiated cells and producing fully dosage compensated DS neurons. Additionally, I show that silencing of the trisomic chromosome in neural stem cells enhances their terminal differentiation to neurons, and transcriptome analysis provides evidence of a specific pathway involved. Separate experiments utilize novel three-dimensional organoid technology and transcriptome analysis to model DS neurodevelopment in relation to isogenic euploid cells. Overall, this work demonstrates that dosage compensation provides a powerful experimental tool to examine early DS neurodevelopment, and establishes that XIST function does not require pluripotency, thereby overcoming a perceived obstacle to the potential of XIST as a therapeutic strategy for trisomy.
dc.language.isoen_US
dc.rightsLicensed under a Creative Commons license
dc.rights.urihttp://creativecommons.org/licenses/by-nc/4.0/
dc.subjectDown syndrome
dc.subjectXIST
dc.subjectdosage compensation
dc.subjectneurodevelopment
dc.subjectorganoids
dc.subjectiPS
dc.subjectCell Biology
dc.subjectDevelopmental Neuroscience
dc.subjectMedical Genetics
dc.titleModeling Down Syndrome Neurodevelopment with Dosage Compensation
dc.typeDoctoral Dissertation
dc.identifier.legacyfulltexthttps://escholarship.umassmed.edu/cgi/viewcontent.cgi?article=2046&context=gsbs_diss&unstamped=1
dc.identifier.legacycoverpagehttps://escholarship.umassmed.edu/gsbs_diss/1037
dc.legacy.embargo2020-07-11T00:00:00-07:00
dc.identifier.contextkey15026716
refterms.dateFOA2022-08-25T04:31:58Z
html.description.abstract<p>Due to their underlying genetic complexity, chromosomal disorders such as Down syndrome (DS), which is caused by trisomy 21, have long been understudied and continue to lack effective treatments. With over 200 genes on the extra chromosome, even the specific cell pathologies and pathways impacted in DS are not known, and it has not been considered a viable target for the burgeoning field of gene therapy. Recently, our lab demonstrated that the natural mechanism of dosage compensation can be harnessed to silence the trisomic chromosome in pluripotent cells. Using an inducible <em>XIST</em> transgene allows us to study the effects of trisomy in a tightly controlled system by comparing the same cells with either two or three active copies of chromosome 21. In addition, it raises the prospect that insertion of a single gene into a trisomic chromosome could potentially be developed in the future for “chromosome therapy”.</p> <p>This thesis aims to utilize this inducible system for dosage compensation to study the neurodevelopmental effects of trisomy 21 <em>in vitro</em>, and to answer basic epigenetic questions critical to the viability of chromosome silencing as a therapeutic approach. Foremost, for <em>XIST</em> to have any prospect as a therapeutic, and to strengthen its experimental utility, it must be able to initiate chromosome silencing beyond its natural context of pluripotency. Here I demonstrate that, contrary to the current literature, <em>XIST</em> is capable of initiating chromosome silencing in differentiated cells and producing fully dosage compensated DS neurons. Additionally, I show that silencing of the trisomic chromosome in neural stem cells enhances their terminal differentiation to neurons, and transcriptome analysis provides evidence of a specific pathway involved. Separate experiments utilize novel three-dimensional organoid technology and transcriptome analysis to model DS neurodevelopment in relation to isogenic euploid cells. Overall, this work demonstrates that dosage compensation provides a powerful experimental tool to examine early DS neurodevelopment, and establishes that <em>XIST</em> function does not require pluripotency, thereby overcoming a perceived obstacle to the potential of <em>XIST</em> as a therapeutic strategy for trisomy.</p>
dc.identifier.submissionpathgsbs_diss/1037
dc.contributor.departmentNeurology
dc.description.thesisprogramMD/PhD
dc.identifier.orcid0000-0002-2576-4192


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