Transcriptional Programming of Human Mechanosensory Neuron Subtypes from Pluripotent Stem Cells

Abstract

Highlights d NGN2-BRN3A expression in human stem cells induces homogeneous sensory neurons (iSNs) d Three kinds of iSNs can be produced, including subtypes coexpressing TRPM8 and PIEZO2 d TRPM8 and PIEZO2 unexpectedly mark a subset of sensory neurons in humans, but not mice d iSNs from PIEZO2-deficient patients are insensitive to mechanical stimuli

Transcription Factor-Based Fate Specification and Forward Programming for Neural Regeneration

“…Already Serre et al (2012) noted that the four different bHLH TFs NGN1, NGN2, NGN3, and ASCL1 had slightly varying effects on neuronal subtype specification from human primary cortical NPCs, although cultures generally consisted of a mixed population of GABAergic, cholinergic, serotoninergic, adrenergic, and MNs (Serre et al, 2012). This observation is in line with other reports demonstrating divergent effects for different bHLH TFs on neuronal subtype derivation: Overexpression of ASCL1 induces a GABAergic bias in neuronal cultures differentiating from neurospheres isolated from both human fetal cortex and mesencephalon (Kim et al, 2009), whereas NGN2 overexpression in human iPSC-derived NPCs (Ho et al, 2016) and PSCs (Zhang et al, 2013;Nehme et al, 2018;Meijer et al, 2019;Rhee et al, 2019;Nickolls et al, 2020) leads to the derivation of mostly glutamatergic neurons.…”

Human Induced Pluripotent Stem Cell Derived Sensory Neurons are Sensitive to the Neurotoxic Effects of Paclitaxel

“…In contrast, neuroectodermal spheres from human ESCs and iPSCs were differentiated into neural crest cells and induced into sensory neurons that expressed almost exclusively NTRK2 and yielded functional low threshold mechanoreceptors 30 . A BRN3A and NGN2 transcription factor-driven differentiation of iPSCs was recently described and yields a homogeneous population of sensory neurons that express mostly NTRK1 and co-express TRPM8 and PIEZO2; these sensory neurons function as low threshold mechanoreceptors that also respond to cold stimuli 31 . Interestingly, application of the BRN3A/NGN2 transcription factor differentiation to a neural crest population derived from neuroectodermal spheres yielded two distinct sensory neuron populations; one expresses TRPM8 and PIEZO2 sensory neurons and a separate population derived by only transient BRN3A/NGN2 expression followed by culturing with neurotrophic factors expresses high levels of PIEZO2 but not TRPM8 31 .…”

“…A BRN3A and NGN2 transcription factor-driven differentiation of iPSCs was recently described and yields a homogeneous population of sensory neurons that express mostly NTRK1 and co-express TRPM8 and PIEZO2; these sensory neurons function as low threshold mechanoreceptors that also respond to cold stimuli 31 . Interestingly, application of the BRN3A/NGN2 transcription factor differentiation to a neural crest population derived from neuroectodermal spheres yielded two distinct sensory neuron populations; one expresses TRPM8 and PIEZO2 sensory neurons and a separate population derived by only transient BRN3A/NGN2 expression followed by culturing with neurotrophic factors expresses high levels of PIEZO2 but not TRPM8 31 . While there are clear differences in sensory neuron populations related to the method of differentiation and induction 24,26,[30][31][32] , significant variability in iPSC-derived models of human disease has also been attributed to the iPSC genetic background, somatic mutations and variations in their culturing and maintenance 33 .…”

“…Interestingly, application of the BRN3A/NGN2 transcription factor differentiation to a neural crest population derived from neuroectodermal spheres yielded two distinct sensory neuron populations; one expresses TRPM8 and PIEZO2 sensory neurons and a separate population derived by only transient BRN3A/NGN2 expression followed by culturing with neurotrophic factors expresses high levels of PIEZO2 but not TRPM8 31 . While there are clear differences in sensory neuron populations related to the method of differentiation and induction 24,26,[30][31][32] , significant variability in iPSC-derived models of human disease has also been attributed to the iPSC genetic background, somatic mutations and variations in their culturing and maintenance 33 . The largest source of variation among sensory neurons derived from a large number of iPSC lines in a single institution with a standardized protocol was batch-to-batch variation across differentiations 24 .…”

“…Despite these potential batch-to-batch differences, the results from the current study were collected over several years and the neurotoxicity phenotypes of interest were reproducible over this period. Future studies will address the effect of paclitaxel and other chemotherapeutic agents in more homogeneous sensory neuron populations, such as the cold and mechanosensitive neurons described recently 31 .…”