The human cerebral cortex is largest in humans compared to other mammals. A line of neurons that creases around in circles to fit within the skull, the human cortex maintains advanced bodily functions – its the very organ that enables us to see, hear and understand our surroundings. Recent research has shown that specific IncRNA (long non-coding RNA) controls the development of these neurons.
It was found that these so called IncRNA produce mRNA that regulates the synthesis of key proteins known as Notch proteins. Notch proteins consist of a group of transmembrane molecules that exhibit continuous extracellular domains that are involved in embryogenesis.
It was found that these IncRNA bound mRNA similar to a sponge. In order to reproduce the results, the research team used human stem cells to produce neurons into what’s commonly known as a “mini brain” – a small lobed brain tissue no bigger than the size of a pea. Subsequently, it was noted that brain stem cells known as glia were found to be responsible for the synthesis of IncRNA related compounds.
Whilst these results were promising in showing the role of glia in the production of IncRNA, the scientists nevertheless wanted to replicate findings in an actual human brain. They thus turned to their colleagues at UC San Fransico. Together they conducted further experimentation which confirmed that IncRNA was indeed present in the early stages of neuron formation, but not in fully grown neurons.
Further mouse model experimentation was conducted whereby IncRNA was introduced into the brain of gestating mice. Fluorescent labelling was then used to examine the early patterns of neuron formation under MRI. It was observed that IncRNA developed from glial cells – quite surprising considering that these sorts of molecules are usually only found in humans and their closely related primates. Furthermore, actual functional development was observed utilizing IncRNA.
The research is interesting since it identifies the key genes associated with neuron development in humans. In addition it offers clues as to how neurogenesis (neuron creation) occurs within humans- particularly in developmental pathways involving Notch signalling.
Study Source –
Neha Rani, Tomasz J. Nowakowski, Hongjun Zhou, Sirie E. Godshalk, Véronique Lisi, Arnold R. Kriegstein, Kenneth S. Kosik. “A Primate lncRNA Mediates Notch Signaling during Neuronal Development by Sequestering miRNA”. Neuron, 2016;