Biology subjects

Broughton, K.

Publications and source records attributed to Broughton, K..

3 recordsLinked to original sources

bioRxiv2019

Human CardioChimeras: Creation of a Novel \"Next Generation\" Cardiac Cell

BackgroundCardioChimeras (CCs) produced by fusion of murine c-kit+ cardiac interstitial cells (cCIC) with mesenchymal stem cells (MSCs) promote superior structural and functional recovery in a mouse model of myocardial infarction (MI) compared to either precursor cell alone or in combination. Creation of human CardioChimeras (hCC) represents the next step in translational development of this novel cell type, but new challenges arise when working with cCICs isolated and expanded from human heart tissue samples. The objective of the study was to establish a reliable cell fusion protocol for consistent optimized creation of hCCs and characterize fundamental hCC properties.\n\nMethods and ResultsCell fusion was induced by incubating human cCICs and MSCs at a 2:1 ratio with inactivated Sendai virus. Hybrid cells were sorted into 96-well microplates for clonal expansion to derive unique cloned hCCs, which were then characterized for various cellular and molecular properties. hCCs exhibited enhanced survival relative to the parent cells and promoted cardiomyocyte survival in response to serum deprivation in vitro.\n\nConclusionsThe generation of hCC is demonstrated and validated in this study, representing the next step toward implementation of a novel cell product for therapeutic development. Feasibility of creating human hybrid cells prompts consideration of multiple possibilities to create novel chimeric cells derived from cells with desirable traits to promote healing in pathologically damaged myocardium.\n\nClinical PerspectiveO_LI\"Next generation\" cell therapeutics will build upon initial findings that demonstrate enhanced reparative action of combining distinct cell types for treatment of cardiomyopathic injury.\nC_LIO_LIDifferential biological properties of various cell types are challenging for optimization of delivery, engraftment, persistence, and synergistic action when used in combination.\nC_LIO_LICreation of a novel hybrid cell called a CardioChimera overcomes limitations inherent to use of multiple cell types.\nC_LIO_LICardioChimeras exhibit unique properties relative to either parental cell anticipated to be advantageous in cellular therapeutic applications.\nC_LIO_LICardioChimeras have now been created and characterized using cells derived from human heart tissue, advancing initial proof of concept previously demonstrated with mice.\nC_LIO_LICardioChimeras represent an engineered solution that can be implemented as a path forward for improving the outcome of myocardial cell therapy.\nC_LI

cell biology↗

bioRxiv2019

Tetraploidy in rodent cardiac stem cells confers enhanced biological properties

Ploidy for cardiomyocytes is well described but remains obscure in cardiac interstitial cells (CICs). Ploidy of c-kit+CICs were assessed using a combination of confocal, karyotypic, and flow cytometric assessments coupled with molecular and bioinformatic analyses. Fundamental differences were found between cultured rodent (rat, mouse) c-kit+CICs possessing mononuclear tetraploid (4n) content versus large mammal (human, swine) with mononuclear diploid (2n) content. In-situ analysis, confirmed with fresh isolates, revealed diploid content in c-kit+CICs from human and a mixture of diploid and tetraploid nuclei in mouse. Molecular assessment of the p53 signaling pathway provides a plausible explanation for escape from replicative senescence in rodent but not human ckit+CICs. Single cell transcriptional profiling reveals distinctions between diploid versus tetraploid populations in mouse ckit+CICs, alluding to functional divergences. Collectively, these data reveal fundamental species-specific biological differences in c-kit+CICs that could account for challenges in extrapolation of myocardial preclinical studies from rodent to large animal models.

cell biology↗

bioRxiv2019

Safety profiling of genetically engineered Pim-1 kinase overexpression for oncogenicity risk in human c-kit+ cardiac interstitial cells

Advanced approaches to stem cell-based therapies is necessary for myocardial regenerative therapy because treatments have yielded modest results in the clinic. Our group previously demonstrated genetic modification of cardiac stem cells with Pim-1 kinase overexpression rejuvenated aged cells and potentiated myocardial repair. Despite these encouraging findings, concerns were raised regarding oncogenic risk associated with Pim-1 kinase overexpression. Testing of these c-kit+ cardiac interstitial cells (cCICs), derived from heart failure patient samples, overexpressing Pim-1 (cCICs-Pim-1) for indices of oncogenic risk was assessed by soft agar colony formation, micronucleation, gamma-Histone 2AX foci, and transcriptome profiling. Collectively, findings demonstrate comparable phenotypic and biological properties of cCICsPim-1 compared to baseline control cCICs with no evidence for oncogenic phenotype. Using a highly-selective and continuous sensor for quantitative assessment of PIM1 kinase activity, a 7-fold increase in cCICs-Pim-1 versus cCICs resulted. Kinase activity was elevated in IKKs, AKT/SGK, CDK1-3, p38, and ERK1/2 in addition to Pim-1, correlating Pim-1 overexpression to contribute to Pim-1-mediated effects. Enhancement of cellular survival, proliferation, and other beneficial properties to augment stem cell-mediated repair without oncogenic risk is a feasible, logical, and safe approach to improve efficacy and overcome current limitations inherent to cellular adoptive transfer therapeutic interventions.

cell biology↗