Restoring sight with algae genes?

Optogenetics has multiple applications in basic research, with promising clinical perspectives. Focus on its use in a patient suffering from retinitis pigmentosa.

Optogenetics is a technique combining 𝐥𝐢𝐠𝐡𝐭 𝐬𝐭𝐢𝐦𝐮𝐥𝐚𝐭𝐢𝐨𝐧 𝐚𝐧𝐝 𝐠𝐞𝐧𝐞𝐭𝐢𝐜𝐬. Through genetic modification, specific cells are able to 𝐩𝐫𝐨𝐝𝐮𝐜𝐞 𝐩𝐫𝐨𝐭𝐞𝐢𝐧𝐬, 𝐜𝐚𝐥𝐥𝐞𝐝 𝐨𝐩𝐬𝐢𝐧𝐬, which transmit an electrical signal when stimulated by light. There are several families of opsins, including the 𝐜𝐡𝐚𝐧𝐧𝐞𝐥𝐫𝐡𝐨𝐝𝐨𝐩𝐬𝐢𝐧 family, which is originally found in 𝐮𝐧𝐢𝐜𝐞𝐥𝐥𝐮𝐥𝐚𝐫 𝐚𝐥𝐠𝐚𝐞.

Optogenetics is a particularly interesting area of research in the treatment of blindness. The retina's photoreceptors transform visual information into electrical messages transmitted to the brain via the optic nerve. 𝐑𝐞𝐭𝐢𝐧𝐢𝐭𝐢𝐬 𝐩𝐢𝐠𝐦𝐞𝐧𝐭𝐨𝐬𝐚 is caused by photoreceptor degeneration. This therapy was 𝐭𝐞𝐬𝐭𝐞𝐝 𝐢𝐧 𝟐𝟎𝟐𝟏 on a 58-year-old patient with advanced retinitis pigmentosa, enabling him to 𝐩𝐚𝐫𝐭𝐢𝐚𝐥𝐥𝐲 𝐫𝐞𝐠𝐚𝐢𝐧 𝐡𝐢𝐬 𝐬𝐢𝐠𝐡𝐭. Several months after intraocular injection of the channelrhodopsin-encoding gene, the patient was 𝐚𝐛𝐥𝐞 𝐭𝐨 𝐥𝐨𝐜𝐚𝐭𝐞, 𝐜𝐨𝐮𝐧𝐭, 𝐚𝐧𝐝 𝐭𝐨𝐮𝐜𝐡 𝐨𝐛𝐣𝐞𝐜𝐭𝐬 with the help of special goggles, which was impossible before the injection.

In terms of perspectives, the researchers then planned to 𝐦𝐚𝐧𝐢𝐩𝐮𝐥𝐚𝐭𝐞 𝐭𝐡𝐞 𝐞𝐱𝐩𝐫𝐞𝐬𝐬𝐢𝐨𝐧 𝐨𝐟 𝐜𝐡𝐚𝐧𝐧𝐞𝐥𝐫𝐡𝐨𝐝𝐨𝐩𝐬𝐢𝐧, so that more cells would be able to respond, and with weaker light signals. However, even if the results obtained on this patient are promising and constitute a 𝐩𝐫𝐨𝐨𝐟 𝐨𝐟 𝐜𝐨𝐧𝐜𝐞𝐩𝐭, there is still a long way to go before therapeutic use.