The average cost to bring a new drug from its initial discovery to a patient's bedside is estimated to surpass $2 billion and requires over a decade of research and development. There is a need for new drug screening technologies that can parse drug candidates with increased likelihood of clinical utility early in development in order to increase the cost-effectiveness of this pipeline. For example, during the COVID-19 pandemic, resources were rapidly mobilized to identify effective therapeutic treatments but many lead antiviral compounds failed to demonstrate efficacy when progressed to human trials. To address the lack of predictive preclinical drug screening tools, PREDICT96-ALI, a high-throughput ( n = 96) microphysiological system (MPS) that recapitulates primary human tracheobronchial tissue,is adapted for the evaluation of differential antiviral efficacy of native SARS-CoV-2 variants of concern. Here, PREDICT96-ALI resolves both the differential viral kinetics between variants and the efficacy of antiviral compounds over a range of drug doses. PREDICT96-ALI is able to distinguish clinically efficacious antiviral therapies like remdesivir and nirmatrelvir from promising lead compounds that do not show clinical efficacy. Importantly, results from this proof-of-concept study track with known clinical outcomes, demonstrate the feasibility of this technology as a prognostic drug discovery tool.
COVID-19 emerged as a worldwide pandemic in early 2020, and while the rapid development of safe and efficacious vaccines stands as an extraordinary achievement, the identification of effective therapeutics has been less successful. This process has been limited in part by a lack of human-relevant preclinical models compatible with therapeutic screening on the native virus, which requires a high-containment environment. Here, we report SARS-CoV-2 infection and robust viral replication in PREDICT96-ALI, a high-throughput, human primary cell-based organ-on-chip platform. We evaluate unique infection kinetic profiles across lung tissue from three human donors by immunofluorescence, RT-qPCR, and plaque assays over a 6-day infection period. Enabled by the 96 devices/plate throughput of PREDICT96-ALI, we also investigate the efficacy of Remdesivir and MPro61 in a proof-of-concept antiviral study. Both compounds exhibit an antiviral effect against SARS-CoV-2 in the platform. This demonstration of SARS-CoV-2 infection and antiviral dosing in a high-throughput organ-on-chip platform presents a critical capability for disease modeling and therapeutic screening applications in a human physiology-relevant in vitro system.
In the United States, 1 in 10 infants are born preterm. The majority of neonatal deaths and nearly a third of infant deaths are linked to preterm birth. Preterm birth is initiated when the quiescent state of the uterus ends prematurely, leading to contractions and parturition beginning as early as 32 weeks, though the origins are not well understood. To enable research and discovery of therapeutics with potential to better address preterm birth, the capability to study isolated cell processes of pregnant uterine tissue in vitro is needed. Our development of an in vitro model of the myometrium utilizing human uterine smooth muscle cells (uSMCs) responsible for contractions provides a methodology to examine cellular mechanisms of late-stage pregnancy potentially involved in preterm birth. We discuss culture of uSMCs on a flexible polydimethylsiloxane (PDMS) substrate functionalized with cationic poly-l-lysine (PLL), followed by extracellular matrix (ECM) protein coating. Previous work exploring uSMC behavior on PDMS substrates have utilized collagen-I coatings, however, we demonstrated the first exploration of human uSMC response to strain on fibronectin-coated flexible membranes, importantly reflecting the significant increase of fibronectin content found in the myometrial ECM during late-stage pregnancy. Using the model we developed, we conducted proof-of-concept studies to investigate the impact of substrate strain on uSMC cell morphology and gene expression. It was found that PLL and varied ECM protein coatings (collagen I, collagen III, and fibronectin) altered cell nuclei morphology and density on PDMS substrates. Additionally, varied strain rates applied to uSMC substrates significantly impacted uSMC gene expression of IL-6, a cytokine associated with instances of preterm labor. These results suggest that both surface and mechanical properties of in vitro systems impact primary human uSMC phenotype and offer uSMC culture methodologies that can be utilized to further the understanding of cellular pathways involved in the uterus under mechanical load.
The intestinal epithelium comprises diverse cell types and executes many specialized functions as the primary interface between luminal contents and internal organs. A key function provided by the epithelium is maintenance of a barrier that protects the individual from pathogens, irritating luminal contents, and the microbiota. Disruption of this barrier can lead to inflammatory disease within the intestinal mucosa, and, in more severe cases, to sepsis. Animal models to study intestinal permeability are costly and not entirely predictive of human biology. Here we present a model of human colon barrier function that integrates primary human colon stem cells into Draper’s PREDICT96 microfluidic organ-on-chip platform to yield a high-throughput system appropriate to predict damage and healing of the human colon epithelial barrier. We have demonstrated pharmacologically induced barrier damage measured by both a high throughput molecular permeability assay and transepithelial resistance. Using these assays, we developed an Inflammatory Bowel Disease-relevant model through cytokine induced damage that can support studies of disease mechanisms and putative therapeutics.
Despite the relatively common observation of therapeutic efficacy in discovery screens with immortalized cell lines, the vast majority of drug candidates do not reach clinical development. Candidates that do move forward often fail to demonstrate efficacy when progressed from animal models to humans. This dilemma highlights the need for new drug screening technologies that can parse drug candidates early in development with regard to predicted relevance for clinical use. PREDICT96-ALI is a high-throughput organ-on-chip platform incorporating human primary airway epithelial cells in a dynamic tissue microenvironment. Here we demonstrate the utility of PREDICT96-ALI as an antiviral screening tool for SARS-CoV-2, combining the high-throughput functionality of a 96-well plate format in a high containment laboratory with the relevant biology of primary human tissue. PREDICT96-ALI resolved differential efficacy in five antiviral compounds over a range of drug doses. Complementary viral genome quantification and immunofluorescence microscopy readouts achieved high repeatability between devices and replicate plates. Importantly, results from testing the three antiviral drugs currently available to patients (nirmatrelvir, molnupiravir, and remdesivir) tracked with clinical outcomes, demonstrating the value of this technology as a prognostic drug discovery tool.
Influenza and other respiratory viruses present a significant threat to public health, national security, and the world economy, and can lead to the emergence of global pandemics such as from COVID-19. A barrier to the development of effective therapeutics is the absence of a robust and predictive preclinical model, with most studies relying on a combination of in vitro screening with immortalized cell lines and low-throughput animal models. Here, we integrate human primary airway epithelial cells into a custom-engineered 96-device platform (PREDICT96-ALI) in which tissues are cultured in an array of microchannel-based culture chambers at an air–liquid interface, in a configuration compatible with high resolution in-situ imaging and real-time sensing. We apply this platform to influenza A virus and coronavirus infections, evaluating viral infection kinetics and antiviral agent dosing across multiple strains and donor populations of human primary cells. Human coronaviruses HCoV-NL63 and SARS-CoV-2 enter host cells via ACE2 and utilize the protease TMPRSS2 for spike protein priming, and we confirm their expression, demonstrate infection across a range of multiplicities of infection, and evaluate the efficacy of camostat mesylate, a known inhibitor of HCoV-NL63 infection. This new capability can be used to address a major gap in the rapid assessment of therapeutic efficacy of small molecules and antiviral agents against influenza and other respiratory viruses including coronaviruses.
Urinary tract infections (UTIs) are among the most common infectious diseases worldwide but are significantly understudied. Uropathogenic E. coli (UPEC) accounts for a significant proportion of UTI, but a large number of other species can infect the urinary tract, each of which will have unique host-pathogen interactions with the bladder environment. Given the substantial economic burden of UTI and its increasing antibiotic resistance, there is an urgent need to better understand UTI pathophysiology – especially its tendency to relapse and recur. Most models developed to date use murine infection; few human-relevant models exist. Of these, the majority of in vitro UTI models have utilized cells in static culture, but UTI needs to be studied in the context of the unique aspects of the bladder’s biophysical environment (e.g., tissue architecture, urine, fluid flow, and stretch). In this review, we summarize the complexities of recurrent UTI, critically assess current infection models and discuss potential improvements. More advanced human cell-based in vitro models have the potential to enable a better understanding of the etiology of UTI disease and to provide a complementary platform alongside animals for drug screening and the search for better treatments.
COVID-19 emerged as a worldwide pandemic early in 2020, and at this writing has caused over 170 million cases and 3.7 million deaths worldwide, and almost 600,000 deaths in the United States. The rapid development of several safe and highly efficacious vaccines stands as one of the most extraordinary achievements in modern medicine, but the identification and administration of efficacious therapeutics to treat patients suffering from COVID-19 has been far less successful. A major factor limiting progress in the development of effective treatments has been a lack of suitable preclinical models for the disease, currently reliant upon various animal models and in vitro culture of immortalized cell lines. Here we report the first successful demonstration of SARS-CoV-2 infection and viral replication in a human primary cell-based organ-on-chip, leveraging a recently developed tissue culture platform known as PREDICT96. This successful demonstration of SARS-CoV-2 infection in human primary airway epithelial cells derived from a living donor represents a powerful new pathway for disease modeling and an avenue for screening therapeutic candidates in a high throughput platform.
Drug development suffers from a lack of predictive and human-relevant in vitro models. Organ-on-chip (OOC) technology provides advanced culture capabilities to generate physiologically appropriate, human-based tissue in vitro, therefore providing a route to a predictive in vitro model. However, OOC technologies are often created at the expense of throughput, industry-standard form factors, and compatibility with state-of-the-art data collection tools. Here we present an OOC platform with advanced culture capabilities supporting a variety of human tissue models including liver, vascular, gastrointestinal, and kidney. The platform has 96 devices per industry standard plate and compatibility with contemporary high-throughput data collection tools. Specifically, we demonstrate programmable flow control over two physiologically relevant flow regimes: perfusion flow that enhances hepatic tissue function and high-shear stress flow that aligns endothelial monolayers. In addition, we integrate electrical sensors, demonstrating quantification of barrier function of primary gut colon tissue in real-time. We utilize optical access to the tissues to directly quantify renal active transport and oxygen consumption via integrated oxygen sensors. Finally, we leverage the compatibility and throughput of the platform to screen all 96 devices using high content screening (HCS) and evaluate gene expression using RNA sequencing (RNA-seq). By combining these capabilities in one platform, physiologically-relevant tissues can be generated and measured, accelerating optimization of an in vitro model, and ultimately increasing predictive accuracy of in vitro drug screening.