Pattern of Functional TTX-Resistant Sodium Channels Reveals a Developmental Stage of Human iPSC- and ESC-Derived Nociceptors

Abstract

SummaryHuman pluripotent stem cells (hPSCs) offer the opportunity to generate neuronal cells, including nociceptors. Using a chemical-based approach, we generated nociceptive sensory neurons from HUES6 embryonic stem cells and retrovirally reprogrammed induced hPSCs derived from fibroblasts. The nociceptive neurons expressed respective markers and showed tetrodotoxin-sensitive (TTXs) and -resistant (TTXr) voltage-gated sodium currents in patch-clamp experiments. In contrast to their counterparts from rodent dorsal root ganglia, TTXr currents of hPSC-derived nociceptors unexpectedly displayed a significantly more hyperpolarized voltage dependence of activation and fast inactivation. This apparent discrepancy is most likely due to a substantial expression of the developmentally important sodium channel NAV1.5. In view of the obstacles to recapitulate neuropathic pain in animal models, our data advance hPSC-derived nociceptors as a better model to study developmental and pathogenetic processes in human nociceptive neurons and to develop more specific small molecules to attenuate pain.

Composite Pain Biomarker Signatures for Objective Assessment and Effective Treatment

“…It is now possible to differentiate iPSCs into many defined types of neurons, e.g., nociceptors, cortical neurons, and MNs although a limitation is that typically they remain immature. For pain, the capacity to generate human nociceptors from stem cells is certainly most promising (Chambers et al, 2012;Eberhardt et al, 2015;Wainger et al, 2015), especially for studying channelopathies like those arising from Nav1.7 mutations (Yang et al, 2018) where the hyperexcitability phenotype is easy to capture either electrophysiologically or with calcium reporter readouts. More complex three-dimensional multicell organoids for modeling cortex (Madhavan et al, 2018;Sloan et al, 2018) and skin (Lee et al, 2018a) are being developed and offer exciting new ways to study complex non-cell-autonomous phenotypes.…”

Generation of iPSC-Derived Human Peripheral Sensory Neurons Releasing Substance P Elicited by TRPV1 Agonists

“…Nevertheless, although most neurons exhibited those markers, few showed important functional readouts, such as TRPV1 activation, as only about 1-2% of the cells responded to capsaicin. Other studies were able to demonstrate the expression of canonical peripheral markers, such as BRN3A, peripherin and b-Tubulin III, in sensory neurons derived from hiPSCs, but evidence of specific functional activity was still missing (Menendez et al, 2013, Young et al, 2014, Blanchard et al, 2015, Eberhardt et al, 2015. Young et al (2014) reported measuring TRPV1 activity induced by capsaicin, but only after 6 weeks in medium containing growth factors.…”

“…Literature analysis reveals the efforts made by several groups to develop more efficient and costeffective protocols for obtaining functional peripheral neurons from human induced pluripotency stem cells (Menendez et al, 2013, Young et al, 2014Blanchard et al, 2015, Eberhardt et al, 2015. However, none of these studies have shown results with human cells or investigated the role of the interaction between human epidermal keratinocytes and the transcriptional profile of mature neurons in the presence of factors released by these cells.…”

Cell‐based therapies and natural compounds for pain

“…A follow‐up study using electrophysiology techniques later showed that these cells expressed functional ion channels that have been implicated in the pathophysiology of pain and sensory disorders (including HCN1, KCNQ2/3 and GABA A R) . This protocol, amongst others, has subsequently been used to screen for neurotoxic agents and therapeutic drugs to block hyperexcitability of these known targets associated with pain .…”