Engineered red Opto-mGluR6 Opsins, a red-shifted optogenetic excitation tool, an in vitro study

Area of Science:

• Ophthalmology
• Neuroscience
• Biotechnology

Background:

• Degenerative eye diseases lead to blindness via photoreceptor degeneration.
• Optogenetic gene therapy uses genetics and light to control neuron function.
• Current Opto-mGluR6 therapy risks retinal photochemical damage due to high light intensity requirements.

Purpose of the Study:

• To design and evaluate red-shifted Opto-mGluR6 photopigments for safer optogenetic gene therapy.
• To overcome the limitations of blue light sensitivity and photochemical damage associated with existing therapies.
• To develop novel variants with excitation spectra shifted towards longer, safer wavelengths.

Main Methods:

• Bioinformatics and computational studies to design red-shifted variants (ROM17, ROM18, ROM19).
• Synthesis, cloning into pAAV-CMV-IRES-EGFP vector, and functional assessment in HEK-GIRK cells.
• Spectrophotometry and patch clamp experiments to confirm light sensitivity and G-protein signaling.

Main Results:

• Successfully designed and synthesized ROM17, ROM18, and ROM19, red-shifted variants of Opto-mGluR6.
• Confirmed expression and functional light-gated G-protein signaling in engineered cells.
• Demonstrated maximum excitation shifts of approximately 40nm (ROM17), 70nm (ROM18), and 126nm (ROM19) compared to the original Opto-mGluR6.

Conclusions:

• ROM17, ROM18, and ROM19 are novel, red-shifted photopigments suitable for optogenetic gene therapy.
• These variants significantly reduce the risk of photochemical damage by enabling activation with longer wavelengths.
• The developed photopigments offer a safer and potentially more effective approach for treating blindness caused by photoreceptor degeneration.