Thiruvananthapuram: What if the brain could cure itself of neuro-degenerative diseases like Parkinson’s? Scientists at Rajiv Gandhi Centre for Biotechnology (RGCB) led by Jackson James and a team comprising Dhanesh S.B. and Riya Ann Paul have come upon a discovery, which might help activate the quiescent stem cells inside an adult brain. This might help develop a non-invasive cure for neuro-degenerative diseases; but that’s for later. Neural stem cells reside in a few places in the brain like the ventricular zone and hippocampus. Left to themselves, these don’t divide, unlike how it was in the early stages of life.
Scientists want to see if these could divide, produce the required neurons which are degenerating through the maintenance of the neural stem cell pool. “We wanted to understand the mechanism that maintains neural stem cells and what it is that helps it to go to the next phase of a progenitor,” says Jackson James. The neural stem cell undergoes asymmetric division, producing a differentiated cell and a daughter stem cell identical to the mother. Normally, a signalling pathway, known as notch-dependent Hes-1 pathway, ensures that the daughter stem cell is prevented from turning into a differentiated cell.
The notch, a protein from the progenitor, kickstarts a series of processes which finally activates Hes-1. One of the important functions of Hes-1 protein is to repress genes which are needed to make a neuron and thereby maintain the progenitor. “Quite accidentally, we discovered that there are other factors which can induce Hes-1 activation in a Notch independent manner. In the early stages of life, chemicals, known as growth factors induced it. We have shown that neural stem cells are maintained by Notch independent Hes-1 in the developing neo-cortex and these then transit into Notch dependent Hes-1 expressing neural progenitors and latter differentiate into neurons. However, it was not known whether such a system exists in neural stem cells in an adult brain,” says Jackson James. The paper was published in Cerebral Cortex Advance Access.
