Fixing spinal cord injuries
Spinal cord injuries are emblematic of the sort of medical challenge that defies easy or imminent solution. Paralysis is so, well, permanent. But researchers are chipping away at the problem and they are finding glimmers of an answer in surprising places.
In a paper published in The Journal of Biological Chemistry, principal investigator Wendy M. Campana, PhD, professor in the Department of Anesthesiology at UC San Diego School of Medicine and colleagues say a protein known for its role in maintaining cholesterol homeostasis appears to promote axon growth and regeneration after spinal cord injury.
The low-density lipoprotein receptor-related protein 1 (LRP1) is involved in endocytosis, a process used by cells to absorb molecules too large to pass through their membranes. Specifically, it regulates chylomicrons, one of five major groups of lipoproteins that enable cholesterol to move within the water-based solution of the bloodstream.
But it also acts as a signaling receptor, promoting gene expression that leads to changes in cell physiology. After an injury, Campana said that animal models showed molecules are released that bind to LRP1 and activate its receptor. In neurons, this activation triggers the signaling of neurotrophic growth factors which ultimately lead to new, reparative axonal growth.
The findings are particularly notable because they identify an entirely novel mechanism for promoting axonal sprouting and regeneration in the central nervous system after injury.
“The idea is that drugs can be made that activate LRP1 and this, in turn, could be potentially useful for treating spinal cord injury, and possibly peripheral nerve injury,” said Campana.
“There is also a possibility that such drugs could be a way of treating traumatic brain injury and stroke. We are investigating this now. With luck, drugs could be developed – I’m working on this with Jerry Yang - it’s possible that drugs could be developed and moved along to clinical programs over the next few years.”