New Horizons in Cellular Optogenetics

Biological research using optogenetics as a tool has advanced our knowledge significantly over the last couple of years. This novel experimental tool has provided an ever-increasing armory to understand behavioral processes, neural networks, cellular signaling, genome editing, and many more cellular events. Beyond naturally occurring photoreceptors, engineered receptors have spawned a variety of genetically encodable actuators that allow to modulate/control several biological processes by light. The neuroscience field has arguably benefited the most from the modern optogenetic toolkit that encompasses both genetically encodable optical actuators and sensors to control and monitor in real-time neural signaling, regulation, developmental processes, behavioral response(s), neuropathies, etc. Optogenetics thus enabled researchers to manipulate and understand brain function with high spatiotemporal precision, and with clear implications for future therapeutics. For instance, the combination of optogenetics with cerebral organoids represents a very precise and controlled systems to explore neuroanatomy, neural circuits, aberrant neurodevelopment processes, as well as neurodegenerative diseases. Currently, efficient and precise targeting of the optogenetic tools into sub-cellular compartment of the neural system is not well established. It is also required to establish and utilize novel optogenetic methods to control the flux of selective ion, clustering of ion channel proteins and protein homeostasis in neural cellular physiological processes. A Research Topic addressing these and other important cellular neurophysiology events using native and engineered optogenetic tools is envisaged.

The discovery, characterization, and adaptation of new modular photoreceptors for optogenetic control of proteasome machinery, cytoskeleton system, autophagy, cell cycle, ciliary signaling, lipid signaling, DNA and RNA metabolism and other biological processes will greatly advance cellular optogenetics. A wide repertoire of photoreceptors combined with gene-delivery and illumination technologies has sparked the development of novel optogenetic tools and their utilization in basics sciences and translational applications, including optogenetic therapy.We anticipate that this Research Topic gathering cutting-edge articles on optogenetics will garner the interest of neuroscientists and would inspire researchers to exploit unexplored avenues of the cellular optogenetic tools. Hence, we propose an issue for Front Neuroscience dedicated to research, concept note, technological advancement and review articles that will jointly convey current advances and the state-of-the-art of the optogenetic field. A list of relevant subject areas is provided below:

• the engineering and application of novel photoreceptors with custom-tailored light-dependent biological function
• neural and cellular optogenetics (light-gated ion channels and receptors to control downstream processes away from the membrane)
• strategies for cellular and subcellular targeting
• optogenetic sensors and actuators
• optogenetic pharmacology (also known as chemooptogenetics)