Development of a Scalable, High-Throughput-Compatible Assay to Detect Tau Aggregates Using iPSC-Derived Cortical Neurons Maintained in a Three-Dimensional Culture Format

Tau aggregation is the pathological hallmark that best correlates with the progression of Alzheimer's disease (AD). The presence of neurofibrillary tangles (NFTs), formed of hyperphosphorylated tau, leads to neuronal dysfunction and loss, and is directly associated with the cognitive decline observed in AD patients. The limited success in targeting β-amyloid pathologies has reinforced the hypothesis of blocking tau phosphorylation, aggregation, and/or spreading as alternative therapeutic entry points to treat AD. Identification of novel therapies requires disease-relevant and scalable assays capable of reproducing key features of the pathology in an in vitro setting. Here we use induced pluripotent stem cells (iPSCs) as a virtually unlimited source of human cortical neurons to develop a robust and scalable tau aggregation model compatible with high-throughput screening (HTS). We downscaled cell culture conditions to 384-well plate format and used Matrigel to introduce an extra physical protection against cell detachment that reduces shearing stress and better recapitulates pathological conditions. We complemented the assay with AlphaLISA technology for the detection of tau aggregates in a high-throughput-compatible format. The assay is reproducible across users and works with different commercially available iPSC lines, representing a highly translational tool for the identification of novel treatments against tauopathies, including AD.

[Diagnostic work-up in Whipple's disease with cerebral involvement]

The diagnostic work-up in the case of a suspected cerebral involvement of Whipple's disease involves neuroimaging and analysis of cerebrospinal fluid (CSF) including polymerase chain reaction (PCR) assays for Tropheryma whipplei. As neurological findings may be complex and unspecific, extracerebral symptoms often lead to the suspicion of Whipple's disease. We report the cases of two patients in whom the suspected diagnosis of Whipple's disease could not be proved either by endoscopy or by the analysis of CSF. Only by means of a cerebral biopsy was the diagnosis assumed and specific therapy was initiated.

The High Throughput Screening Infrastructure: The Right Tools for the Task

HTS is a key component of pharmaceutical lead identification process. Over recent years, the pharmaceutical industry has experienced significant increases in the throughput capabilities of its HTS functions. In those companies where HTS has been effectively deployed, it is now possible to screen the entire corporate compound collection against a pharmacological target within a timescale of several weeks to a few months. This capability has been realized, not as a result of the purchase of any one particular piece of hardware, but rather through the development of a truly effective HTS infrastructure that matches the needs of the parent organization. Central to this is the need to understand how to effectively combine the use of the different types of hardware available to the HTS specialist. The use of both modular workstations and single-arm robotic systems have underpinned most HTS groups operations. Recent advances in the field of multiple-arm robotic systems and dedicated automation systems offer even further potential for increasing productivity. This article describes our experience with the use of a dedicated automation system for HTS applications.