The Lamprey Regenerates Its Spinal Cord Not Just Once – but Twice

Marine Biological Laboratory (MBL) scientists determine central nervous system regeneration with ZEISS microscopes

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Spontaneous recovery from spinal cord injury is almost unheard of in humans and other mammals, but many vertebrates fare better. The eel-like lamprey, for instance, can fully regenerate its spinal cord even after it’s been severed – within three months the lamprey is swimming, burrowing, and flipping around again, as if nothing had happened.

In a new study, Marine Biological Laboratory (MBL) scientists report that lampreys recover and regenerate just as impressively after a second complete spinal cord injury at the same location. The study opens up a new path for identifying pro-regenerative molecules and potential therapeutic targets for human spinal cord injury.

Research insights

“We’ve determined that central nervous system (CNS) regeneration in lampreys is resilient and robust after multiple injuries. The regeneration is nearly identical to the first time, both anatomically and functionally,” said senior author Jennifer Morgan, Director of the MBL’s Eugene Bell Center for Regenerative Biology and Tissue Engineering.

Morgan’s lab has been focusing on the descending neurons, which originate in the brain and send motor signals down to the spinal cord. Some of these descending neurons regenerate after CNS injury in lamprey, while others die.

“Using ZEISS Axio Imager M2 and ZEISS Axio Zoom.V16 stereo microscopes, as well as a ZEISS LSM confocal microscope, we were able to visualize the regenerating neurons in great detail. This allowed us to describe and quantify the regenerating neurons, thus enabling the major results of the study,” said Morgan.

Lamprey spinal cord
Longitudinal section of a lamprey spinal cord at 11 weeks post-injury, showing many regenerated axons (green) and a repaired central canal (blue tubelike structure). The original lesion site is in the center of the image. Credit: S. Allen and J. Morgan

“We are beginning to isolate individual descending neurons and look at their transcriptional profiles (gene activity) to see if we can determine what makes some of them better at regenerating than others,” Morgan said. “The ‘good’ regenerators, for example, may express molecules that are known to promote growth during development. That’s one hypothesis.”

Sea Lamprey and Regeneration – Jennifer Morgan from Marine Biological Laboratory on Vimeo.

 

Better strategies for treatments

Observing how the descending neurons respond to a second CNS injury can help the team tease out the factors required for repeated, resilient regeneration, which could have implications for designing better strategies for treatments aimed at promoting CNS re-growth after injury or disease.

Read the present study, published in PLOS ONE, here

Regeneration has been a core area of research at the Marine Biological Laboratory since its founding, particularly in the pioneering work of Nobel laureate Thomas Hunt Morgan, an embryologist and geneticist whose 1901 text “Regeneration” is a classic in the field.

Over a century later Morgan’s lab in particular has led many breakthroughs, including a 2018 study that found genes that aid spinal cord healing in lamprey are also present in mammals.

In 2010, the Eugene Bell Center for Regenerative Biology and Tissue Engineering was established at MBL in honor of Eugene Bell (1919-2007), a pioneer of tissue engineering and a valued member of the MBL scientific community. Scientists in the Bell Center, in collaboration with colleagues at the University of Chicago and the Argonne National Laboratory, are providing new insights into the basic mechanisms of tissue growth, repair and regeneration in all metazoans that will permit novel approaches to the understanding, treatment and prevention of human disease.

Tags: Confocal Microscopy, Light Microscopy

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