Regeneration of axons
Restoration of damaged nerves is possible
Sergey Syrov, XX2 century
The most severe consequences of various kinds of injuries are loss of sensitivity and motor functions of body parts. They happen when nerves are damaged – bundles of axons, elongated processes of nerve cells. Medicine is powerless in such cases – grown axons have a weak ability to recover.
But things can change. A new work by specialists from the Lewis Katz School of Medicine at Temple University (LKSOM) shows that restoring the normal functioning of the nervous system after injuries is possible, and the key to this is a molecule regulating cell growth, known as Lin28.
An article published in the journal Molecular Therapy (Nathan et al., Upregulating Lin28a Promotes Axon Regeneration in Adult Mice with Optic Nerve and Spinal Cord Injury) reports axon repair in adult mice with spinal cord or optic nerve injury. This was made possible by the increased expression of the Lin28 gene.
"Our results show that Lin28 is the main regulator of axon regeneration and a promising therapeutic target for injuries of the central nervous system," says one of the project leaders, Professor of anatomy and cell biology Shuxin Li.
The regenerative potential of Lin28 in animal spinal cord injury has been demonstrated for the first time.
To study the impact Lin28 for axon regeneration, Professor Li and colleagues have developed a line of mice with overexpression Lin28 in some fabrics. The adult animals were divided into groups, one group had a spinal cord damaged, the other had an optic nerve.
A group of adult mice with normal expression also participated in the experiments Lin28. They received the same damage, after which Lin28 was injected into them using a viral vector, thus the direct effect of the molecule on tissue repair was studied.
The excess of Lin28 stimulated the regeneration of axons in all cases, but this was especially noticeable in the case of injection of Lin28 after injury. In mice with spinal cord injury, the injection led to the growth of axons by more than three millimeters beyond the axon damage zone, in animals with optic nerve damage, axons grew along the entire length of the optic nerve tract. The motor activity and vision of the mice were restored.
The immediate goal is to identify safe and effective means of delivering Lin28 to damaged tissues in sick people. To do this, we need to develop a vector (delivery vehicle) for Lin28, capable of reaching damaged nerves. It is also necessary to study the Lin28 signaling pathway more fully, to find out which other molecules are involved in the growth of nerve cells, and how they can be used in medicine.
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