Thermogenetic neurostimulation with single-cell resolution

Abstract

Thermogenetics is a promising innovative neurostimulation technique, which enables robust activation of neurons using thermosensitive transient receptor potential (TRP) cation channels. Broader application of this approach in neuroscience is, however, hindered by a limited variety of suitable ion channels, and by low spatial and temporal resolution of neuronal activation when TRP channels are activated by ambient temperature variations or chemical agonists. Here, we demonstrate rapid, robust and reproducible repeated activation of snake TRPA1 channels heterologously expressed in non-neuronal cells, mouse neurons and zebrafish neurons in vivo by infrared (IR) laser radiation. A fibre-optic probe that integrates a nitrogen−vacancy (NV) diamond quantum sensor with optical and microwave waveguide delivery enables thermometry with single-cell resolution, allowing neurons to be activated by exceptionally mild heating, thus preventing the damaging effects of excessive heat. The neuronal responses to the activation by IR laser radiation are fully characterized using Ca2+ imaging and electrophysiology, providing, for the first time, a complete framework for a thermogenetic manipulation of individual neurons using IR light.

Stimulation of water and calcium dynamics in astrocytes with pulsed infrared light

“…Direct thermal activation of TRPA1 is unlikely, as its debated thermal activation is prominently for cold stimuli rather than warm 7,36 . A recent work suggested a direct activation of TRPA1 by transient heat induced by ultrafast infrared laser pulse,51 but the temperature‐time dynamics explored were quite different from those explored in this study. Interestingly, a recent study reported the implication of TRPA1 in osmotic‐induced Ca 2+ influx 52 .…”

Dissecting the Role of Subtypes of Gastrointestinal Vagal Afferents

“…Similar to its predecessors, thermogenetics permits controlled activation or inhibition of neuronal activity using thermal stimulus (Bernstein et al, 2012). Molecules with inhibitory effects, e.g., Drosophila melanogaster dynamin GTPase (Kitamoto, 2001) and excitatory effects from the thermoTRP family (Dhaka et al, 2006), e.g., Drosophila melanogaster TRPA1 (Viswanath et al, 2003;Hamada et al, 2008), rat TRPM8 (Peier et al, 2002;Peabody et al, 2009) and snake TRPA1 (Ermakova et al, 2017), have been discovered. Studies have demonstrated a successful thermal-induced neural activity modulation in drosophila, zebra fish and mouse cultured neurons, but no evidence in in vivo models have been reported (Bath et al, 2014;Ermakova et al, 2017).…”

Temperature Rise under Two-Photon Optogenetic Brain Stimulation

“…Our model is extendable to other brain regions or biological preparations differing in scattering properties, thus offering a unique and flexible tool for the design of complex optogenetics experiments with minimal sample heating. It will surely prove useful also to simulate the temperature distribution under different excitation configurations (including single-and threephoton excitation) and imaging geometries (e.g., light sheet microscopy, stimulated emission depletion microscopy, or Bessel beam illumination) or to optimize light distribution and illumination conditions for thermogenetic experiments (Bernstein et al, 2012;Ermakova et al, 2017;Hamada et al, 2008).…”