Electrically-evoked oscillating calcium transients in mono- and co-cultures of iPSC glia and sensory neurons

Phenotypic Screening of Prospective Analgesics Among FDA-Approved Compounds using an iPSC-Based Model of Acute and Chronic Inflammatory Nociception

Classical target-based drug screening is low-throughput, largely subjective, and costly. Phenotypic screening based on in vitro models is increasingly being used to identify candidate compounds that modulate complex cell/tissue functions. Chronic inflammatory nociception, and subsequent chronic pain conditions, affect peripheral sensory neuron activity (e.g., firing of action potentials) through myriad pathways, and remain unaddressed in regard to effective, non-addictive management/treatment options. Here, a chronic inflammatory nociception model is demonstrated based on induced pluripotent stem cell (iPSC) sensory neurons and glia, co-cultured on microelectrode arrays (MEAs). iPSC sensory co-cultures exhibit coordinated spontaneous extracellular action potential (EAP) firing, reaching a stable baseline after ≈27 days in vitro (DIV). Spontaneous and evoked EAP metrics are significantly modulated by 24-h incubation with tumor necrosis factor-alpha (TNF-α), representing an inflammatory phenotype. Compared with positive controls (lidocaine), this model is identified as an "excellent" stand-alone assay based on a modified Z' assay quality metric. This model is then used to screen 15 cherry-picked, off-label, Food and Drug Administration (FDA)-approved compounds; 10 of 15 are identified as "hits". Both hits and "misses" are discussed in turn. In total, this data suggests that iPSC sensory co-cultures on MEAs may represent a moderate-to-high-throughput assay for drug discovery targeting inflammatory nociception.

Accelerated differentiation of human induced pluripotent stem cells into regionally specific dorsal and ventral spinal neural progenitor cells for application in spinal cord therapeutics

Spinal cord injury can attenuate both motor and sensory function with minimal potential for full recovery. Research utilizing human induced pluripotent stem cell (hiPSC) -derived spinal cell types for in vivo remodeling and neuromodulation after spinal cord injury has grown substantially in recent years. However, the majority of protocols for the differentiation of spinal neurons are lengthy, lack the appropriate dorsoventral or rostrocaudal specification, and are not typically replicated in more than one cell line. Furthermore, most researchers currently utilize hiPSC-derived motor neurons for cell transplantation after injury, with very little exploration of spinal sensory neuron transplantation. The lack of studies that utilize sensory populations may be due in part to the relative scarcity of dorsal horn differentiation protocols. Building upon our previously published work that demonstrated the rapid establishment of a primitive ectoderm population from hiPSCs, we describe here the production of a diverse population of both ventral spinal and dorsal horn progenitor cells. Our work creates a novel system allowing dorsal and ventral spinal neurons to be differentiated from the same intermediate ectoderm population, making it possible to construct the dorsal and ventral domains of the spinal cord while decreasing variability. This technology can be used in tandem with biomaterials and pharmacology to improve cell transplantation for spinal cord injury, increasing the potential for neuroregeneration.