Rapid generation of human sensory neurons from iPSC for modeling of peripheral neuropathies

Genetic and acquired forms of small fiber neuropathies lead to debilitating health conditions, resulting in pain or loss of sensation. These neuropathies are caused by dysfunction or degeneration of unmyelinated peripheral sensory axons: c fibers. Rodent models have been used to investigate molecular mechanisms leading to neuropathies and search for potential therapeutic targets. Although these studies have advanced our understanding of small fiber neuropathies, rodent studies don't fully recapitulate human diseases. Sensory neurons derived from human induced pluripotent stem cells (iPSC) hold promise towards advancing the field of small fiber neuropathies.

Here, we report a quick and efficient protocol to generate human sensory neurons from iPSC within ten days.

The generated neurons expressed generic sensory markers (Brn3A, Islet 1, and neurofilament M) as well as the sensory neuron-associated sodium channel subtypes NaV1.7 and NaV1.8. Additionally, ∼80% of generated sensory neurons were positive for transient receptor potential vanilloid 1 (TRPV-1), a marker for unmyelinated sensory axons.

Previous investigators have generated sensory neurons from iPSCs, with a protocol length range of up to 42 days. Most methodologies either employ a small molecule differentiation or an "accelerated" method, whereas our new model is generated by utilizing mRNA.

This novel protocol enables rapid generation of human sensory neurons from human iPSCs, achieving 60-70% efficiency. A shorter protocol can improve modeling of small-fiber neuropathies - for example, diabetic peripheral neuropathy and toxic conditions like chemotherapy-induced peripheral neuropathy.