Publications by authors named "Harrison E Grace"

3 Publications

  • Page 1 of 1

mRNA Reprogramming of T8993G Leigh's Syndrome Fibroblast Cells to Create Induced Pluripotent Stem Cell Models for Mitochondrial Disorders.

Stem Cells Dev 2019 07 20;28(13):846-859. Epub 2019 May 20.

7 Department of Biological Sciences, Fulbright College of Arts and Sciences, University of Arkansas, Fayetteville, Arkansas.

Early molecular and developmental events impacting many incurable mitochondrial disorders are not fully understood and require generation of relevant patient- and disease-specific stem cell models. In this study, we focus on the ability of a nonviral and integration-free reprogramming method for deriving clinical-grade induced pluripotent stem cells (iPSCs) specific to Leigh's syndrome (LS), a fatal neurodegenerative mitochondrial disorder of infants. The cause of fatality could be due to the presence of high abundance of mutant mitochondrial DNA (mtDNA) or decline in respiration levels, thus affecting early molecular and developmental events in energy-intensive tissues. LS patient fibroblasts (designated LS1 in this study), carrying a high percentage of mutant T8993G mtDNA, were reprogrammed using a combined mRNA-miRNA nonviral approach to generate human iPSCs (hiPSCs). The LS1-hiPSCs were evaluated for their self-renewal, embryoid body (EB) formation, and differentiation potential, using immunocytochemistry and gene expression profiling methods. Sanger sequencing and next-generation sequencing approaches were used to detect the mutation and quantify the percentage of mutant mtDNA in the LS1-hiPSCs and differentiated derivatives. Reprogrammed LS-hiPSCs expressed pluripotent stem cell markers including transcription factors OCT4, NANOG, and SOX2 and cell surface markers SSEA4, TRA-1-60, and TRA-1-81 at the RNA and protein level. LS1-hiPSCs also demonstrated the capacity for self-renewal and multilineage differentiation into all three embryonic germ layers. EB analysis demonstrated impaired differentiation potential in cells carrying high percentage of mutant mtDNA. Next-generation sequencing analysis confirmed the presence of high abundance of T8993G mutant mtDNA in the patient fibroblasts and their reprogrammed and differentiated derivatives. These results represent for the first time the derivation and characterization of a stable nonviral hiPSC line reprogrammed from a LS patient fibroblast carrying a high abundance of mutant mtDNA. These outcomes are important steps toward understanding disease origins and developing personalized therapies for patients suffering from mitochondrial diseases.
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July 2019

Human iNPC therapy leads to improvement in functional neurologic outcomes in a pig ischemic stroke model.

Brain Behav 2018 05 18;8(5):e00972. Epub 2018 Apr 18.

Regenerative Bioscience Center University of Georgia Athens GA USA.

Introduction: Stroke is the leading cause of disability in the United States but current therapies are limited with no regenerative potential. Previous translational failures have highlighted the need for large animal models of ischemic stroke and for improved assessments of functional outcomes. The aims of this study were first, to create a post-stroke functional outcome assessment scale in a porcine model of middle cerebral artery occlusion (MCAO) and second, to use this scale to determine the effect of human-induced-pluripotent-cell-derived neural progenitor cells (iNPCs) on functional outcome in this large animal stroke model.

Materials And Methods: Eight 6-month-old Landrace mix pigs underwent permanent MCAO. Five days following MCAO, pigs received intraparenchymal injections of either iNPCs or PBS. A post-stroke assessment scale was developed to measure functional outcome. Evaluations were performed at least 1-3 days prior to MCAO and repeated 1 day, 3 days, and 5 days post-stroke as well as 1 day, 3 days, 1 week, 2 weeks, 4 weeks, 6 weeks, 9 weeks, and 12 weeks post-injection. Comparisons of scores between animals receiving iNPCs or PBS only were compared using a two-way ANOVA and a Tukey's post-hoc test.

Results: The developed scale was able to consistently determine differences between healthy and stroked pigs at all time points. iNPC-treated pigs showed a significantly faster recovery in their overall scores relative to PBS-only treated pigs with the parameters of appetite and body posture exhibiting the most improvement in the iNPC-treated group.

Conclusions: We developed a robust and repeatable functional assessment tool that can reliably detect stroke and recovery, while also showing for the first time that iNPC therapy leads to functional recovery in a translational pig ischemic stroke model. These promising results suggest that iNPCs may 1 day serve as a first in class cell therapeutic for ischemic stroke.
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May 2018

Induced Pluripotent Stem Cell-Derived Neural Stem Cell Therapy Enhances Recovery in an Ischemic Stroke Pig Model.

Sci Rep 2017 08 30;7(1):10075. Epub 2017 Aug 30.

Regenerative Bioscience Center, University of Georgia, Athens, GA, 30602, USA.

Induced pluripotent stem cell-derived neural stem cells (iNSCs) have significant potential as an autologous, multifunctional cell therapy for stroke, which is the primary cause of long term disability in the United States and the second leading cause of death worldwide. Here we show that iNSC transplantation improves recovery through neuroprotective, regenerative, and cell replacement mechanisms in a novel ischemic pig stroke model. Longitudinal multiparametric magnetic resonance imaging (MRI) following iNSC therapy demonstrated reduced changes in white matter integrity, cerebral blood perfusion, and brain metabolism in the infarcted tissue. The observed tissue level recovery strongly correlated with decreased immune response, enhanced neuronal protection, and increased neurogenesis. iNSCs differentiated into neurons and oligodendrocytes with indication of long term integration. The robust recovery response to iNSC therapy in a translational pig stroke model with increased predictive potential strongly supports that iNSCs may be the critically needed therapeutic for human stroke patients.
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August 2017