A calcium- and light-gated switch to induce gene expression in activated neurons

Abstract

Despite recent advances in optogenetics, it remains challenging to manipulate gene expression in specific populations of neurons. We present a dual-protein switch system, Cal-Light, that translates neuronal-activity-mediated calcium signaling into gene expression in a light-dependent manner. In cultured neurons and brain slices, we show that Cal-Light drives expression of the reporter EGFP with high spatiotemporal resolution only in the presence of both blue light and calcium. Delivery of the Cal-Light components to the motor cortex of mice by viral vectors labels a subset of excitatory and inhibitory neurons related to learned lever-pressing behavior. By using Cal-Light to drive expression of the inhibitory receptor halorhodopsin (eNpHR), which responds to yellow light, we temporarily inhibit the lever-pressing behavior, confirming that the labeled neurons mediate the behavior. Thus, Cal-Light enables dissection of neural circuits underlying complex mammalian behaviors with high spatiotemporal precision.

Near‐Infrared Light Activated Thermosensitive Ion Channel to Remotely Control Transgene System for Thrombolysis Therapy

“…As shown in Figure i, obvious up‐regulation of uPA expression was exclusively observed in transfected cells under both PMSF −DyLight ‐DBCO treatment and NIR. To validate the amount and activity of secreted uPA, the content and dynamics of the uPA activity were evaluated by chromogenic substrate assay . As shown in Figure j,k, the amount of expressed uPA was time‐dependently up‐regulated with relatively high activity in the supernatant of PMSF −DyLight ‐DBCO treated and NIR irradiated cells, which also indicated a significant increase in functional uPA expression.…”

“…In such applications, it is crucial to precisely control the timing and dose of therapeutic agent production by receiving external signals. Among external stimulus signals such as small chemicals, radio waves, magnetic field, etc., light is considered to be a signal source because of its precise spatiotemporal control ability, easy tunableness, and convenient operation . Currently, light‐switchable gene expression systems have been used to control cellular functions and mainly rely on ultraviolet or visible light sources due to the limitation of photoactive proteins with a low tissue penetration depth .…”

“…Among external stimulus signals such as small chemicals, radio waves, magnetic field, etc., light is considered to be a signal source because of its precise spatiotemporal control ability, easy tunableness, and convenient operation . Currently, light‐switchable gene expression systems have been used to control cellular functions and mainly rely on ultraviolet or visible light sources due to the limitation of photoactive proteins with a low tissue penetration depth . In contrast, near‐infrared (NIR) light holds deeper tissue penetration and causes less photodamage to target cells under the same parameter conditions including light dosage and exposure time .…”

rsCaMPARI: an erasable marker of neuronal activity

“…An alternative approach is to mark the active neuron ensemble during a behavior of interest for post-hoc analysis. These methods often couple calcium activity with light activation in order to drive a fluorescence change or to activate transcription factors 13,14 .…”

Highly efficient and super-bright neurocircuit tracing using vector mixing-based virus cocktail

“…Multiple rAAVs are extensively involved in basic and clinical researches where coexpression of multiple genes is needed 1 . In neural circuit studies, multiple rAAVsmediated systems have been broadly used for brain-wide mapping of long-range projections [2][3][4][5] , tracing of direct input networks [6][7][8][9][10][11] and manipulating and monitoring of neuronal activities during/for specific behaviour [12][13] .…”