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News, Research

Australian scientist identifies molecule that can stop dry AMD

04/09/2019By Myles Hume
A Canberra researcher is working on ways to harness gene-regulating molecules that have shown promise in halting the progression of conditions such as atrophic age-related macular degeneration (AMD).

Dr Joshua Chu-Tan, from the Australian National University’s John Curtin School of Medical Research, is currently developing a preventative gene therapy using microRNA, which he describes as “the gods of gene regulation”.

"We know inflammatory pathways plays a major role in AMD and tiny molecules called microRNA can fight them in a multi-pronged way," he said.

"When we inject anti-inflammatory mircoRNA into the eye we see a decrease in the expression of genes responsible for inflammation and cell death, as well as a slowing in the damage progression of the retina.”

Specifically, Chu-Tan discovered that microRNA-124 shows promise as a preventative treatment for AMD. Using a technique called in situ hybridization, his team evaluated the presence of microRNA-124 in AMD donor samples, and compared the results with healthy retinas.

Joshua Chu-Tan
Joshua Chu-Tan
"By injecting a cocktail of these molecules we think we can slow the progression of this disease and hopefully halt vision loss”
Joshua Chu-Tan, ANU

It was found the age-comparable healthy individuals had an abundance of microRNA-124 across the entire retina, whereas the AMD patients had none in the central part of the retina.

"However in an AMD patient's periphery of the retina, where there is no damage, there is microRNA-124,” he said.

In a study, the researchers supplemented microRNA-124 into the eyes of animal models, which had retinal damage, via intravitreal injections.

“We found that these animals had better retinal function and less cell death in the retina and less inflammation. We published this study last year,” Chu-Tan said.

“The power in these microRNA is that they bind to RNA and effectively stop them from being read, and stop the protein from being produced. The benefit in these microRNA also lie in their ability to control multiple targets, so a single microRNA sequence has the ability to bind up to around 200 different targets.

"We think we have found a major player in slowing the disease with microRNA-124. By injecting a cocktail of these molecules we think we can slow the progression of this disease and hopefully halt vision loss.”

Chu-Tan said the researchers would now focus on analysing the particular targets the microRNA-124 molecule acts to control, as well as how its functions in the retina.

“We want to really try and go after this molecule more so we can obtain plenty of preliminary data if we were to take it even further,” he said.


More reading:

Australian researchers trial blood test for AMD
Eye researchers vie for illustrious Eureka Prize

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