By Holly Giles
The ability of the body to regrow after injury is a well accepted fact; we are not all walking around with cuts on our knees from when we were three as the body is able to heal them and regrow the relevant tissue. However, with neurons this isn’t the case. Until now it was thought that the neurons in your body are there for life and if they become damaged they are unable to regrow. This opinion may have been changed forever through the new research by Dr Shuxin Li and his team at the Lewis Katz School of Medicine Temple University.
They have found this ability of neurons to regrow through the molecule Lin28 and that when Lin28 levels are increased in the site of axon injury, the neurons are able to regrow to their previous size. “Our findings show that Lin28 is a major regulator of axon regeneration and a promising therapeutic target for central nervous system injuries,” explained Dr Li.
“We became interested in Lin28 as a target for neuron regeneration because it acts as a gatekeeper of stem cell activity, it controls the switch that maintains stem cells or allows them to differentiate and potentially contribute to activities such as axon regeneration” he added.
This research was conducted on mice using animals with Lin28 expressed at heightened levels in their tissues through modification and secondly through injection after injury. The animals then sustained injuries either to the spinal cord or to the optic nerve tracts that connect the retina to the eye. Both groups with increased Lin28 expression showed axon regeneration but the result was the most striking in the models with injection in Lin28 after the injury; here the axon grew to 3mm longer than they were previously, leading to significant improvement in coordination and sensation.
Reflecting on these findings Li said “We observed a lot of axon regrowth, which could be very significant clinically, since there currently are no regenerative treatments for spinal cord injury or optic nerve injury.” The team is now looking for a way to be able to control this switch and, through it, to direct cell growth of new neurons after injuries. This would be revolutionary for patients including stroke sufferers, of which there are over 100,000 in the UK each year.