NCATS experts are applying the techniques of 3-D bioprinting to develop tissue models that mimic the organization and physiology of cells in the tissues of living organisms, in a microplate format for drug screening. Read more about the 3-D bioprinting program in action below.
Building Lung Tissue Models to Speed Virus Drug Testing
Assays used to find drugs with antiviral activity often are not measuring how a drug behaves in the human body, including its ability to halt the virus from infecting cells and how variant mutations affect this ability and disease severity. To solve this challenge, NCATS scientists are developing a cadre of new 3-D tissue models to examine how respiratory viruses like the SARS-CoV-2 virus and influenza viruses can infect the lungs and other tissues and cause disease.
NCATS Announces NIH HEAL Initiative-Related Funding Opportunities
NCATS announced several new funding opportunities through The NIH Helping to End Addiction Long-termSM Initiative, or NIH HEAL InitiativeSM. Through RFA-TR-19-005, NCATS is supporting collaborations with the external research community to develop and use 3-D biofabricated tissue models as new drug screening platforms to advance preclinical discovery and development of non-addictive treatments for pain, opioid use disorder and overdose. NCATS intends to fund approximately two to three awards for a total of $1.5 million in fiscal year 2019.
3-D Tissue Bioprinting: An Emerging Path to Better Drug Development
NCATS scientists are developing 3-D tissue models that more closely mimic the complexity of tissues in the human body in a reproducible, automated and scalable manner using bioprinting techniques. These innovative, human-like tissue models are used for compound testing and could accelerate drug development for treatments of both rare and common diseases.
NCATS Develops New Technique to Look Inside Cells Growing in 3-D
NCATS intramural researchers outline a simple, fast and automated process to make 3-D tissues transparent. The new method, published in the July issue of Scientific Reports, enables many types of observations within 3-D growth environments, such as locating molecules inside a cell or finding damaged DNA, and it can do so quickly in thousands of cells in a tissue-like structure.
A Three-Dimensional Neural Spheroid Model for Capillary-Like Network Formation
In vitro 3-D neural spheroid models have an in vivo-like cell density, and they have the potential to reduce animal usage and increase experimental throughput. The aim of this study was to establish a spheroid model to study the formation of capillary-like networks in a 3-D environment that incorporates both neuronal and glial cell types and does not require exogenous vasculogenic growth factors. This study created self-assembled, scaffold-free cellular spheroids using primary-derived postnatal rodent cortex as a cell source. The interactions between relevant neural cell types, basement membrane proteins, and endothelial cells were characterized via immunohistochemistry. Transmission electron microscopy was used to determine whether endothelial network structures had lumens.
Exploring Drug Dosing Regimens In Vitro Using Real-Time 3-D Spheroid Tumor Growth Assays
The cells used in this study constitutively expressed green fluorescent protein, which enabled the real-time monitoring of spheroid formation and the effect of chemotherapeutic agents on spheroid size at different time points of sphere growth and drug treatment. This real-time 3-D spheroid assay platform represents a first step toward the replication in vitro of drug dosing regimens being investigated in vivo. The authors of this study hope that further development of this assay platform will allow the investigation of drug dosing regimens, efficacy, and resistance before preclinical and clinical studies.
A High-Throughput Screening Model of the Tumor Microenvironment for Ovarian Cancer Cell Growth
The tumor microenvironment plays an important role in the processes of tumor growth, metastasis and drug resistance. This study used a multilayered 3-D primary cell culture model that reproduced the human ovarian cancer metastatic microenvironment to study the effect of the microenvironment on the pharmacological responses of different classes of drugs on cancer cell proliferation.
Large-Scale Pharmacological Profiling of 3-D Tumor Models of Cancer Cells
This study sought to further understand the differences in pharmacological responses between cancer tumor cells grown in different conditions by profiling 1,912 chemotherapeutic agents. The study compared pharmacological responses obtained from cells cultured in traditional 2-D monolayer conditions with those responses obtained from cells forming spheres versus cells already in 3-D spheres. The target annotation of the compound library screened enabled the identification of those key cellular pathways and processes that when modulated by drugs induced cell death in all growth conditions or selectively in the different cell growth models.
Looking Into the Future: Using Induced Pluripotent Stem Cells to Build Two- and Three-Dimensional Ocular Tissue for Cell Therapy and Disease Modeling
Retinal degenerative diseases are the leading cause of irreversible vision loss in developed countries. In many cases, the diseases originate in the homeostatic unit in the back of the eye that contains the retina, the retinal pigment epithelium (RPE) and the choriocapillaris. This article summarizes the recent progress in the field of induced pluripotent stem cell-derived RPE disease modeling and cell therapies and also discusses the possibilities of developing a model of the entire homeostatic unit to aid in studying disease processes in the future.
Superoxide Mediates Tight Junction Complex Dissociation in Cyclically Stretched Lung Slices
This study found that stretching Type I rat alveolar epithelial cell monolayers at magnitudes that correspond to high tidal-volume mechanical ventilation results in the production of reactive oxygen species, including nitric oxide and superoxide. Scavenging superoxide with Tiron eliminated the stretch-induced increase in cell monolayer permeability, and similar results were reported for rats ventilated at large tidal volumes, suggesting that oxidative stress plays an important role in barrier impairment in ventilator-induced lung injury associated with large stretch and tidal volumes.
Three-Dimensional Neural Spheroid Culture: An In Vitro Model for Cortical Studies
There is a high demand for in vitro models of the central nervous system to study neurological disorders, injuries, toxicity and drug efficacy. 3-D in vitro models can bridge the gap between traditional 2-D culture and animal models because they present an in vivo-like microenvironment in a tailorable experimental platform. Within the expanding variety of sophisticated 3-D cultures, scaffold-free, self-assembled spheroid culture avoids the introduction of foreign materials and preserves the native cell populations and extracellular matrix types. In this study, 3-D spheroids were generated with primary postnatal rat cortical cells using an accessible, size-controlled, reproducible and cost-effective method.
Application and Assessment of Optical Clearing Methods for Imaging of Tissue-Engineered Neural Stem Cell Spheres
In this study, the application of three recently published clearing techniques — Clear(T2), Scale and SeeDB — to tissue-engineered neural spheres was assessed. The study found that scaffold-free self-assembled adult hippocampal neural stem cell spheres with a diameter of 100 μm could be optically cleared and imaged using either Clear(T2) or Scale, while SeeDB only marginally improved imaging depth.
Quantitative High-Throughput Screening Using a Primary Human Three-Dimensional Organotypic Culture Predicts In Vivo Efficacy
The tumor microenvironment contributes to cancer metastasis and drug resistance. However, most high-throughput screening (HTS) assays for drug discovery use cancer cells grown in monolayers. This study shows that a multilayered culture containing primary human fibroblasts, mesothelial cells and extracellular matrix can be adapted into a reliable 384- and 1,536-multi-well HTS assay that reproduces the human ovarian cancer metastatic microenvironment.
Mechanical Modulation of Nascent Stem Cell Lineage Commitment in Tissue Engineering Scaffolds
Taking inspiration from tissue morphogenesis in utero, this study tests the concept of using tissue engineering scaffolds as delivery devices to modulate emergent structure-function relationships at early stages of tissue genesis. This study reports on the use of combined computational fluid dynamics modeling, advanced manufacturing methods and experimental fluid mechanics (micro-piv and strain mapping) for the prospective design of tissue engineering scaffold geometries that deliver spatially resolved mechanical cues to stem cells seeded within.
Engineered Single- and Multi-Cell Chemotaxis Pathways in E. Coli
The chemotaxis system of Escherichia coli has been engineered to respond to molecules that are not attractants for wild-type cells. The system depends on an artificially introduced enzymatic activity that converts the target molecule into a ligand for an E. coli chemoreceptor, thereby enabling the cells to respond to the new attractant. Two systems were designed, and both showed robust chemotactic responses in semisolid and liquid media. The first incorporates an asparaginase enzyme and the native E. coli aspartate receptor to produce a response to asparagine; the second uses penicillin acylase and an engineered chemoreceptor for phenylacetic acid to produce a response to phenylacetyl glycine.