Biology subjects

Ball, K.

Publications and source records attributed to Ball, K..

4 recordsLinked to original sources

bioRxiv2025

Quantitative systems pharmacology modeling of pyrrolobenzodiazepine antibody-drug conjugates targeting BCMA

Antibody-drug conjugates (ADCs) are novel therapeutics combining two molecules linked together: an antibody that provides targeting to specific cells, and a cytotoxic drug (warhead) that can deconjugate from the antibody and kill those cells. The warhead by itself would be too nonspecific and toxic; the antibody by itself would be insufficiently effective at killing the cells. As more and more ADCs enter the drug development pipeline, understanding the mechanistic reasons behind efficacy and toxicity is critical to evaluating both successful and failed trials. Here, we have developed a mechanistic computational model of ADCs, and specifically parameterize it using data for MEDI2228, an anti-BCMA antibody conjugated to pyrrolobenzodiazepine (PBD) warheads. We build the model to track not only the concentrations of ADC and its released warhead drug inside and outside the cell, but also to track the recent history of the warhead, so that we can distinguish between pathways for on-target and bystander (nontargeted) cell killing. We show that this effect is predicted to be small under in vitro conditions due to dilution in large volumes of media, but likely to form a significant part of both targeted and nontargeted cell killing in vivo, where the extracellular volume has less of a dilution effect. We also explore the impact of key design parameters of ADCs, including drug to antibody ratio (DAR), warhead potency, and lipophilicity; this analysis demonstrates the balance needed between killing of targeted and nontargeted cells. Using this quantitative systems pharmacology model, we can generate insights for optimization of ADC design and determine which factors are most critical to efficacy and toxicity, leading to more informed and rational development of cancer therapies.

systems biology↗

bioRxiv2020

Lactate promotes cardiomyocyte dedifferentiation through metabolic reprogramming

Cardiomyocytes undergo different metabolic changes during development and differentiation crucial for their maturation and adult function, such as contraction, growth and survival. Alterations of cardiac metabolism have been associated with multiple disease states and pathological hypertrophy. The shift in substrate preference can impair the stress response, but it may also have a role in cell growth and survival. Here, we evaluated the response of cardiomyocytes to the presence of exogenous lactate, an important metabolite for the fetal heart and cardiogenesis. Lactate-exposed mouse primary cardiomyocytes and human iPSC-derived cardiomyocytes quickly acquired a characteristic dedifferentiated phenotype, with enhanced proliferative capacity as determined by an increased expression of cell cycle (Ki67) and cytokinesis (Aurora-B) effectors. This effect was specific to cardiomyocytes and did not affect other heart cell populations (e.g. cardiac fibroblasts). Nevertheless, cardiac fibroblasts exposed to lactate promoted a pro-regenerative environment through the modulation of the release of cytokines (such as Fas, IL-13 or SDF1a). We characterized lactate-induced cardiomyocyte dedifferentiation through RNA-sequencing and gene expression analysis and identified increased expression of BMP10 (a TGF{beta} family protein involved in embryonic cardiomyocyte proliferation and stemness) and proteins associated to cell fate regulation (LIN28, TCIM) together with downregulation of cardiac maturation genes (GRIK1, DGKK). Bottom-up analysis suggested the phenotype promoted by lactate could be related to the activation of hypoxia signaling pathways. This finding indicated that, indeed, lactate may be a key player of hypoxic regenerative responses in the heart, as it usually accumulates as a result of glycolysis. In addition, ex vivo neonatal heart culture showed prolonged beating function and cardiac tissue integrity when culture media was supplemented with lactate. Thus, we conclude that lactate enhances cardiac proliferation by reprogramming cardiomyocytes towards a dedifferentiated stem cell-like state, supporting the notion that modulation of the metabolic microenvironment might be a powerful novel approach for promoting cardiac regeneration and tissue engineering applications.

bioengineering↗

bioRxiv2020

GENERATION OF HEART ORGANOIDS MODELING EARLY HUMAN CARDIAC DEVELOPMENT UNDER DEFINED CONDITIONS

Cardiovascular-related disorders are a significant worldwide health problem. Cardiovascular disease (CVD) is the leading cause of death in developed countries, making up a third of the mortality rate in the US1. Congenital heart defects (CHD) affect ∼1% of all live births2, making it the most common birth defect in humans. Current technologies provide some insight into how these disorders originate but are limited in their ability to provide a complete overview of disease pathogenesis and progression due to their lack of physiological complexity. There is a pressing need to develop more faithful organ-like platforms recapitulating complex in vivo phenotypes to study human development and disease in vitro. Here, we report the most faithful in vitro organoid model of human cardiovascular development to date using human pluripotent stem cells (hPSCs). Our protocol is highly efficient, scalable, shows high reproducibility and is compatible with high-throughput approaches. Furthermore, our hPSC-based heart organoids (hHOs) showed very high similarity to human fetal hearts, both morphologically and in cell-type complexity. hHOs were differentiated using a two-step manipulation of Wnt signaling using chemical inhibitors and growth factors in completely defined media and culture conditions. Organoids were successfully derived from multiple independent hPSCs lines with very similar efficiency. hHOs started beating at ∼6 days, were mostly spherical and grew up to ∼1 mm in diameter by day 15 of differentiation. hHOs developed sophisticated, interconnected internal chambers and confocal analysis for cardiac markers revealed the presence of all major cardiac lineages, including cardiomyocytes (TNNT2+), epicardial cells (WT1+, TJP+), cardiac fibroblasts (THY1+, VIM+), endothelial cells (PECAM1+), and endocardial cells (NFATC1+). Morphologically, hHOs developed well-defined epicardial and adjacent myocardial regions and presented a distinct vascular plexus as well as endocardial-lined microchambers. RNA-seq time-course analysis of hHOs, monolayer differentiated iPSCs and fetal human hearts revealed that hHOs recapitulate human fetal heart tissue development better than previously described differentiation protocols3,4. hHOs allow higher-order interaction of distinct heart tissues for the first time and display biologically relevant physical and topographical 3D cues that closely resemble the human fetal heart. Our model constitutes a powerful novel tool for discovery and translational studies in human cardiac development and disease.Competing Interest StatementThe authors have declared no competing interest.View Full Text

bioengineering↗

bioRxiv2017

Unexpected Early Proteomic Changes in Alzheimer’s Disease Model Mice Synaptosomes

We have employed label-free quantitative proteomics of wild-type and Alzheimers disease (AD) model mice synaptosomes to investigate proteomic changes occurring during AD progression as a prelude to analysis in humans. More than 4000 proteins were analyzed using multiple analysis tools and statistical criteria. Pathway enrichment identified numerous pathways consistent with the current AD knowledge base, including dysregulation of Glutamate Receptor Signaling, Synaptic Long Term Potentiation and Depression, Rho and Rac Signaling, Calcium Signaling, and Oxidative Phosphorylation and Mitochondrial Dysfunction. Additionally, the data demonstrate that a large number of changes occur in the proteome very early relative to the onset of both traditional disease markers such as amyloid accumulation, tau phosphorylation and cognitive dysfunction. These early changes include a number of dysregulated proteins that have novel associations with AD progression. These results reinforce the importance of mechanistic investigations in early disease progression long before the classical markers of Alzheimers disease are observed.

neuroscience↗