Novel Therapeutical Tools and Methods for Treating Blindness

Abstract

The present inventions relates to the use of an isolated nucleic acid molecule comprising a nucleotide sequence coding for a hyperpolarizing light-gated ion channel or pump gene from an archeon or for a light-active fragment of said gene, or the nucleotide sequence complementary to said nucleotide sequence, for treating or ameliorating blindness. The light-gated ion channel or pump gene can be a halorhodopsin gene.

Description

FIELD OF THE INVENTION[0001]The present invention relates to methods of treating blindness. The present invention also relates to constructs for use in treating blindness, as well as their use in the manufacture of a medicament for treating blindness.BACKGROUND OF THE INVENTION[0002]Blindness is a major health problem that disables millions of people worldwide. The most common cause of blindness is the disfunction of the retina. The three most common forms of retinal blindness are retinitis pigmentosa (RP), macular deneneration (MD) and glaucoma (G). In RP and MD the primary problem is the degeneration of photoreceptors and the consequent loss of photosensitivity. There is thus a need to be able to obviate the problems associated with such degeneration of photoreceptors.[0003]One approach has been to develop a retinal prosthesis, a “seeing eye” chip with as many as 1,000 tiny electrodes to be implanted in the eye. This would have the potential to help people who have lost their sigh...

AI Technical Summary

Benefits of technology

[0010]To address this need, the present inventors investigated the capacity of a phylogenetically ancient hyperpolarizing light sensor, such as the halorhodopsin from the archeon (archeabacteria) Natronomas pharaonis (NpHR), specifically expressed in rod and cone photoreceptors for its capacity to restore vision in an experimental model for blindness. Surprisingly, the inventors realized that this receptor on itself could, when introduced into rod and cone photoreceptors, stimulate both the ON- and the OFF-system, and restore some vision on itself, i.e. without the need of any of the numerous other light transduction cascade components usually found in rod and cone photoreceptors

Problems solved by technology

Blindness is a major health problem that disables millions of people worldwide.

The most common cause of blindness is the disfunction of the retina.

In RP and MD the primary problem is the degeneration of photoreceptors and the consequent loss of photosensitivity.

This would have the potential to help people who have lost their sight to regain enough vision to function independently, but the numbers of electrodes is simply insufficient to provide a high degree or level of sight to be obtained.

Moreover, there are problems associated with inserting foreign bodies into the eye.

Although, the research has shown that photosystem I reaction centres can be incorporated into a liposome and are shown to be functional, in that it produces the experimental equivalent of a voltage when light is shone on it, hitherto this has not been shown to work in a retinal cell.

It will be appreciated however, that such a system is extremely complex and problems are likely to arise if the channel is delivered to the wrong type of retinal cells.

However, the expression of the rhodopsin gene is likely to have occurred in a variety of types of cell in the eye which is potentially undesirable and / or problematic.

It also appears that the threshold light intensity required for producing responses is much higher than for normal rod and cone photoreceptors, but there is no teaching of how this may be addressed in, for example, low light environments.

This method has however the disadvantage of being sub-optimal with OFF-cells.

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