Retinal degenerative diseases, such as retinitis pigmentosa (RP) and dry age-related macular degeneration, have led to loss of vision in millions of individuals. Currently, no surgical or medical treatment is available, although optogenetic therapies are in clinical development. We demonstrate vision restoration using multicharacteristics opsin (MCO1) in animal models with degenerated retina. MCO1 is reliably delivered to specific retinal cells via intravitreal injection of adeno-associated virus (vMCO1), leading to significant improvement in visually guided behavior conducted using a radial arm water maze. The time to reach the platform and the number of error arms decreased significantly after delivery of MCO1. Notably, the improvement in visually guided behavior was observed even at light intensity levels orders of magnitude lower than that required for channelrhodopsin-2 opsin. Viability of vMCO1-treated retina is not compromised by chronic light exposure. Safe virus-mediated MCO1 delivery has potential for effective gene therapy of diverse retinal degenerations in patients.
Photodegenerative retinal diseases such as retinitis pigmentosa (RP) and dry age related macular degeneration (dry-
AMD) lead to loss of vision in millions of individuals. Currently, no surgical or medical treatment is available
though optogenetic therapies are in clinical development. Here, we demonstrate vision restoration using Multi-
Characteristics Opsin (MCO1) in animal models with photo-degenerated retina. MCO1 is reliably delivered to
specific retinal cells via intravitreal injection of Adeno-Associated Virus, leading to significant improvement in
visually guided behavior conducted using a radial-arm water maze. The time to reach platform significantly reduced
after delivery of MCO1. Notably, the improvement in visually guided behavior was observed even at light intensity
levels orders of magnitude lower than that required for Channelrhodopsin-2 opsin. Chronic light exposure study
showed that chronic light exposure did not compromise viability of vMCO1-treated retina. Safe virus-mediated
MCO1-delivery has potential for effective gene therapy of diverse retinal degenerations in patients.
Optical manipulation has enabled study of bio-chemical and bio-mechanical properties of the cells. Laser nanosurgery by ultrafast laser beam with appropriate laser parameters provides spatially-targeted manipulation of neurons in a minimal invasiveness manner with high efficiency. We utilized femto-second laser nano-surgery for both axotomy and sub-axotomy of rat cortical neurons. Degeneration and regeneration after axotomy was studied with and without external growth-factor(s) and biochemical(s). Further, axonal injury was studied as a function of pulse energy, exposure and site of injury. The ability to study the response of neurons to localized injury opens up opportunities for screening potential molecules for repair and regeneration after nerve injury. Sub-axotomy enabled transient opening of axonal membrane for optical delivery of impermeable molecules to the axoplasm. Fast resealing of the axonal membrane after sub-axotomy without significant long-term damage to axon (monitored by its growth) was observed. We will present these experimental results along with theoretical simulation of injury due to laser nano-surgery and delivery via the transient pore. Targeted delivery of proteins such as antibodies, genes encoding reporter proteins, ion-channels and voltage indicators will allow visualization, activation and detection of the neuronal structure and function.
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