Guidelines for Microplate Selection in High Content Imaging

Recent Advances in High-Content Imaging and Analysis in iPSC-Based Modelling of Neurodegenerative Diseases

In the field of neurodegenerative pathologies, the platforms for disease modelling based on patient-derived induced pluripotent stem cells (iPSCs) represent a valuable molecular diagnostic/prognostic tool. Indeed, they paved the way for the in vitro recapitulation of the pathological mechanisms underlying neurodegeneration and for characterizing the molecular heterogeneity of disease manifestations, also enabling drug screening approaches for new therapeutic candidates. A major challenge is related to the choice and optimization of the morpho-functional study designs in human iPSC-derived neurons to deeply detail the cell phenotypes as markers of neurodegeneration. In recent years, the specific combination of high-throughput screening with subcellular resolution microscopy for cell-based high-content imaging (HCI) screening allowed in-depth analyses of cell morphology and neurite trafficking in iPSC-derived neuronal cells by using specific cutting-edge microscopes and automated computational assays. The present work aims to describe the main recent protocols and advances achieved with the HCI analysis in iPSC-based modelling of neurodegenerative diseases, highlighting technical and bioinformatics tips and tricks for further uses and research. To this end, microscopy requirements and the latest computational pipelines to analyze imaging data will be explored, while also providing an overview of the available open-source high-throughput automated platforms.

Bioluminescence Methodology for Ion Channel Studies

As key players in cell function, ion channels are important targets for drug discovery and therapeutic development against a wide range of health conditions. Thus, developing assays to reconstitute ion channel macromolecular complexes in physiological conditions and screen for chemical modifiers of protein-protein interactions within these complexes is timely in drug discovery campaigns. For most ion channels, expressing their pore-forming subunit in heterologous mammalian cells has now become a routine procedure. However, reconstituting protein-channel complexes in physiological environments is still challenging, limiting our ability to identify tools and probes based on allosteric mechanisms, which could lead to more targeted and precise modulation of the channel function. Here, we describe the assay development steps to stably reconstitute the interaction between voltage-gated Na⁺ (Nav) channel Nav1.6 and its accessory protein, fibroblast growth factor 14 (FGF14) using the split-luciferase complementation assay (LCA), followed by assay miniaturization and optimization in 384-well plates for in-cell high-throughput screening (HTS) against protein-channel interactions. This optimized LCA can subsequently be used for rapid estimation of hit potency and efficacy via dose-dependency studies, enabling ranking of hits prior to more labor-intensive validation studies. Lastly, we introduce the methodology for rapid functional hit validation studies using semi-automated planar patch-clamp electrophysiology. Our robust, in-cell HTS platform can be adapted to any suitable ion channel complex to explore regulatory pathways of cellular signaling using kinase inhibitors, as well as to screen small molecules for probe development and drug repurposing toward new targets/areas of medicine. Overall, the flexibility of this assay allows users to broadly explore therapeutic options for channelopathy-associated diseases at a fast pace, enabling rapid hypothesis generation in early phase drug discovery campaigns and narrowing down targets prior to more labor-intensive in vivo studies.

A Framework for Optimizing High-Content Imaging of 3D Models for Drug Discovery

Three-dimensional (3D) spheroid models are rapidly gaining favor for drug discovery applications due to their improved morphological characteristics, cellular complexity, long lifespan in culture, and higher physiological relevance relative to two-dimensional (2D) cell culture models. High-content imaging (HCI) of 3D spheroid models has the potential to provide valuable information to help researchers untangle disease pathophysiology and assess novel therapies more effectively. The transition from 2D monolayer models to dense 3D spheroids in HCI applications is not trivial, however, and requires 3D-optimized protocols, instrumentation, and resources. Here, we discuss considerations for moving from 2D to 3D models and present a framework for HCI and analysis of 3D spheroid models in a drug discovery setting. We combined scaffold-free, multicellular spheroid models with scalable, automation-compatible plate technology enabling image-based applications ranging from high-throughput screening to more complex, lower-throughput microphysiological systems of organ networks. We used this framework in three case studies: investigation of lipid droplet accumulation in a human liver nonalcoholic steatohepatitis (NASH) model, real-time immune cell interactions in a multicellular 3D lung cancer model, and a high-throughput screening application using a 3D co-culture model of gastric carcinoma to assess dose-dependent drug efficacy and specificity. The results of these proof-of-concept studies demonstrate the potential for high-resolution image-based analysis of 3D spheroid models for drug discovery applications, and confirm that cell-level and temporal-spatial analyses that fully exploit multicellular features of spheroid models are not only possible but soon will be routine practice in drug discovery workflows.