Reprogrammed Skin Cells Can Treat Blindness

Calendar February 14, 2023 | Posted by admin

Retinal cells grown from stem cells can reach out and connect with neighbors, according to a new study, completing a “handshake” that may show the cells are ready for trials in humans with degenerative eye disorders. Over a decade ago, researchers from the University of Wisconsin–Madison (UW-Madison) developed a way to grow organized clusters of cells, called organoids, that resemble the retina, the light-sensitive tissue at the back of the eye. They coaxed human skin cells reprogrammed to act as stem cells to develop into layers of several types of retinal cells that sense light and ultimately transmit what we see to the brain.

“We wanted to use the cells from those organoids as replacement parts for the same types of cells that have been lost in the course of retinal diseases,” says David Gamm, the UW–Madison ophthalmology professor and director of the McPherson Eye Research Institute whose lab developed the organoids. “But after being grown in a laboratory dish for months as compact clusters, the question remained — will the cells behave appropriately after we tease them apart? Because that is key to introducing them into a patient’s eye.”

During 2022, Gamm and UW–Madison collaborators published studies showing that dish-grown retinal cells called photoreceptors respond like those in a healthy retina to different wavelengths and intensities of light, and that once they are separated from adjacent cells in their organoid, they can reach out toward new neighbors with characteristic biological cords called axons.

“The last piece of the puzzle was to see if these cords had the ability to plug into, or shake hands with, other retinal cell types in order to communicate,” says Gamm, whose new results on successful connections between the cells will be published this week in the Proceedings of the National Academy of Sciences. Cells in the retina and brain communicate across synapses, tiny gaps at the tips of their cords. To confirm that their lab-grown retinal cells have the capacity to replace diseased cells and carry sensory information like healthy ones, the researchers needed to show that they could make synapses.

Source: https://news.wisc.edu/ 
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Long-term memory forming mechanism discovered

Calendar August 19, 2019 | Posted by admin

Your brain has its own box of memories. If you were to hold it in your hand, brush off the dust and open it up, you’d be able to pull out Polaroid snaps of your most treasured memories. Your graduation ceremony perhaps, your wedding day, your daughter’s first words – all things you wouldn’t want to forget. But how does your brain keep these memories in their crystal-clear clarity? The strength of a memory lies in its formation and upkeep. When we create a memory, thin connections, called axons, form between nerve cells in our brain. The point at which two axons connect is called a synapse, and it is the strength of the synapse that determines if the memory is kept or allowed to fade away.

Now, a study in mice carried out by Nobel Prize-winning researchers at Columbia University has shown that a protein called CPEB3 plays an important role in the formation of memories. The team discovered how this protein is stored and used in the brain and hope it could lead to new methods of slowing memory loss in humans.

“The science of how synapses form and are strengthened over time is important for deciphering any disorder in which synapses – and the memories associated with them – degrade and die, such as Alzheimer’s disease,” said Dr Luana Fioriti. CPEB3 is created by the brain’s memory centre, the Hyppocampus. Once produced, it is stored in chamber-like structures called P bodies that protect it from other parts of the cell. It then travels to the synapse between nerve cells where required and is gradually released to help create a specific memory.

The findings suggest that the more CPEB3 released at a synapse, the stronger the connection and thus, the more concrete the resulting memory is. When the protein was removed, the mice could create new memories but were unable to keep them.

Source: https://www.sciencefocus.com/

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