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- Creators: Mason, Hugh S.
Description
Induced pluripotent stem cells (iPSCs) are an intriguing approach for neurological disease modeling, because neural lineage-specific cell types that retain the donors' complex genetics can be established in vitro. The statistical power of these iPSC-based models, however, is dependent on accurate diagnoses of the somatic cell donors; unfortunately, many neurodegenerative diseases are commonly misdiagnosed in live human subjects. Postmortem histopathological examination of a donor's brain, combined with premortem clinical criteria, is often the most robust approach to correctly classify an individual as a disease-specific case or unaffected control. We describe the establishment of primary dermal fibroblasts cells lines from 28 autopsy donors. These fibroblasts were used to examine the proliferative effects of establishment protocol, tissue amount, biopsy site, and donor age. As proof-of-principle, iPSCs were generated from fibroblasts from a 75-year-old male, whole body donor, defined as an unaffected neurological control by both clinical and histopathological criteria. To our knowledge, this is the first study describing autopsy donor-derived somatic cells being used for iPSC generation and subsequent neural differentiation. This unique approach also enables us to compare iPSC-derived cell cultures to endogenous tissues from the same donor. We utilized RNA sequencing (RNA-Seq) to evaluate the transcriptional progression of in vitro-differentiated neural cells (over a timecourse of 0, 35, 70, 105 and 140 days), and compared this with donor-identical temporal lobe tissue. We observed in vitro progression towards the reference brain tissue, supported by (i) a significant increasing monotonic correlation between the days of our timecourse and the number of actively transcribed protein-coding genes and long intergenic non-coding RNAs (lincRNAs) (P < 0.05), consistent with the transcriptional complexity of the brain, (ii) an increase in CpG methylation after neural differentiation that resembled the epigenomic signature of the endogenous tissue, and (iii) a significant decreasing monotonic correlation between the days of our timecourse and the percent of in vitro to brain-tissue differences (P < 0.05) for tissue-specific protein-coding genes and all putative lincRNAs. These studies support the utility of autopsy donors' somatic cells for iPSC-based neurological disease models, and provide evidence that in vitro neural differentiation can result in physiologically progression.
ContributorsHjelm, Brooke E (Author) / Craig, David W. (Thesis advisor) / Wilson-Rawls, Norma J. (Thesis advisor) / Huentelman, Matthew J. (Committee member) / Mason, Hugh S. (Committee member) / Kusumi, Kenro (Committee member) / Arizona State University (Publisher)
Created2013
Description
In the United States, Escherichia coli O157:H7 (E. coli O157:H7) is the most frequent cause of hemolytic uremic syndrome (HUS) and it is also the primary cause of acute renal failure in children. The most common route of the infection is ingestion of contaminated meat or dairy product originating from cattle or vegetables contaminated with bovine manure. Since cattle are the main reservoir for human infection with E. coli O157:H7, the reduction of intestinal colonization by these bacteria in cattle is the best approach to prevent human infections. Intimin is an outer membrane protein of E. coli O157:H7 that plays an important role in adhesion of the bacteria to the host cell. Hence, I proposed to express intimin protein in tomato plants to use it as a vaccine candidate to reduce or prevent intestinal colonization of cattle with E. coli O157:H7. I expressed His-tagged intimin protein in tomato plants and tested the purified plant-derived intimin as a vaccine candidate in animal trials. I demonstrated that mice immunized intranasally with purified tomato-derived intimin produced intimin-specific serum IgG1and IgG2a, as well as mucosal IgA. I further demonstrated that mice immunized with intimin significantly reduced time of the E. coli O157:H7 shedding in their feces after the challenge with these bacteria, as compared to unimmunized mice. Shiga toxin is the major virulence factor that contributes to HUS. Since Shiga toxin B subunit has an important role in the attachment of the toxin to its receptor, I fused intimin to Shiga toxin B subunit to create multivalent subunit vaccine and tested the effects upon immunization of mice with the B subunit when combined with intimin. His-tagged intimin, Shiga toxin B subunit, and Shiga toxin-intimin fusion proteins were expressed in E. coli and purified. I demonstrated that this multivalent fusion protein vaccine candidate elicited intimin- and Shiga toxin B-specific IgG1, IgG2a, and IgA antibodies in mice. I also showed a reduction in the duration of the bacterial shedding after the challenge compared to the control sham-immunized groups.
ContributorsTopal, Emel (Author) / Mason, Hugh S. (Thesis advisor) / Bingham, Scott E. (Committee member) / Mor, Tsafrir (Committee member) / Roberson, Robert W. (Committee member) / Arizona State University (Publisher)
Created2010