microRNAs will help grow the retina from stem cells
The retina, which retains high photosensitivity, has been grown from stem cells
NanoNewsNet based on the materials of Friedrich Miescher Institute for Biomedical Research: Inducing visual functionBotond Roska and Witold Filipowicz from the Friedrich Miescher Institute for Biomedical Research have uncovered the mechanism controlling the preservation of photosensitive photoreceptor "antennas" of the retina and achieved the formation of photosensitive photoreceptors in the retina grown from embryonic stem cells.
This achievement opens up brilliant prospects in the study and treatment of blindness.
In about one third of cases, vision loss is caused by loss of photoreceptor function. Age–related macular degeneration is the most common disease of people in the older age group, whose number is growing. Another retinal disease – retinitis pigmentosa, or Stargardt's disease – affects people of an earlier age and is much less common.
Recently, much attention has been paid to methods of treating retinal diseases based on stem cells. However, progress in this field is hindered by the lack of understanding of the molecular processes controlling the preservation of photosensitive photoreceptor antennas, the so-called outer segments, and the inability to grow a photosensitive retina with functional photoreceptors from stem cells.
However, Botond Roscke, in collaboration with Witold Filipovich, was able to identify two microRNAs – both about 20 nucleotides long – necessary for the dynamic preservation of the outer segment of cones in mice. In the absence of these molecules, microRNA-182 and microRNA-183, the outer segments of the cones and cone vision are lost. Cones are one of two types of retinal photoreceptors. They are responsible for color vision and perception of subtle details of the "picture". Thus, these microRNAs control the preservation of retinal structures that are absolutely necessary to perform most of our visual tasks.
Restoration of the expression of microRNA-182 and microRNA-183 induced the formation of outer segments of photoreceptors in the retina grown from embryonic stem cells and restored the retina sensitivity to light.
A cross-section of the retina of the eye.
Cones are shown in purple,
their outer segments are green.
"Understanding the mechanisms that lead to the formation and preservation of outer segments and, consequently, functional photoreceptors is very important, because now we can grow a functional retina from stem cells under precisely defined conditions," comments Roska. "The next step will be to study the processes leading to the loss of external segments on the retina grown from patients' skin cells, and search for compounds that influence these processes."
This significant study (Busskamp et al., miRNAs 182 and 183 are necessary to maintain adult cone photoreceptor outer segments and visual function), published in the journal Neuron, was started by two very dedicated postdoctoral fellows Volker Busskamp and Jacek Krol more than 5 years ago.
Portal "Eternal youth" http://vechnayamolodost.ru08.07.2014