In an attempt to better understand complicated brain diseases like Alzheimer’s and Parkinson’s, was the inspiration behind this new found method. Experts at Northwestern University and the University of Pittsburgh have come up with an ingenious and successful way to map the proteins inside various types of neurons (or the nerve cells which are the fundamental units/cells of the brain and the nervous system) in the brain of a living animal. Proteins are the building blocks for all cellular functions, so by targeting them, helps in better grasp on the complex brain diseases which would eventually lead to the development of new and refined treatments.

What was done under the new study?

In the new study, researchers engineered a virus to send an enzyme to a precise location in the brain of a living mouse. The enzyme, derived from soybeans, genetically tagged (protein segments that can be fused to a protein of interest to make it fluorescent, making them easy to detect) its neighboring proteins in a predetermined location.

The researchers after validating the technique by imaging the brain with fluorescence and electron microscopy found that their technique took a snapshot of the entire set of proteins inside the living neurons, which can then be analyzed postmortem with mass spectroscopy.

By tagging the proteins and their neighbors, experts are now able to see and study the protein workup within a localised, controlled area and how they interaction with one another.

Scientist used their virus to carry a separate green fluorescent protein, along with the virus carrying the soybean enzyme.

Kozorovitskiy from Northwestern University who is also a senior author of the study stated that the virus essentially acts as a message that we deliver and in this case, the message carried this special soybean enzyme. 

Similarly, in a separate message, the scientists sent the green fluorescent proteins so they could observe which neurons were tagged. Neurons that became green, they inferred that the soybean enzyme was expressed in those units.

Till date protein tagging had taken a backseat as researcher have never been able to amplify and sequence them in the same way as genes and RNA could be. For proteins researchers break them down into peptides (number of amino acid linked in chains) and then place them back together.

Kozorovitskiy states that even though proteins have been out of the loop, everyone recognizes the significance of proteins as they are the ultimate effectors in the cells. Understanding where the proteins are, how they work, and how they work relative to each other is extremely important.

What is the significance behind this research?

With the validation of the new method, scientist now, will be able to apply them to mouse models to learn and comprehend about various neurological diseases.

"We are hoping to extend this approach to start identifying the biochemical modifications on neuronal proteins that occur during specific patterns of brain activity or with changes induced by neuroactive drugs to facilitate clinical advances," Dumrongprechachan said.

"We look forward to taking this to models related to brain diseases and connect those studies to postmortem proteomics (large scale study of proteins produced in an organism) work in the human brain," Kozorovitskiy said. "It's ready to be applied to those models, and we can't wait to get started."

The study published on 11 August 2021 in the journal Nature Communications, has taken an enormous leap towards understanding the brain's millions of distinct proteins, thereby improving our diagnosis and treatment for various neurological illnesses.