Original title: Lifelong Invertebrate Chordate Central Nervous System Regeneration is Driven by a Migrating Pool of Conserved Neural Stem Cells program
Chiara Anselmi, Tom Levy, Jiamu “Chester” Yu, Katherine Ishizuka +10 · September 2026
Most adult animals cannot easily replace lost brain cells. Researchers wanted to know how some creatures continually rebuild their nervous systems throughout their lives. To investigate this, they studied Botryllus schlosseri, a marine chordate that breaks down and completely regrows its entire central nervous system from scratch every week. The team sorted individual cells and sequenced their genetic activity to see how this renewal happens. They discovered that the creature relies on a dedicated pool of stem cells—special cells capable of turning into nervous tissue. These stem cells follow an evolutionary conserved biological pathway to form new, functioning neurons. When researchers transplanted these brain-derived cells through the blood vessels, the cells migrated straight to developing body areas and gathered near injured tissue. Finally, the researchers found that brain aging occurs when this stem cell pool gets exhausted, causing the rebuilding cycle to run out of sync and collapse.
Imagine a bakery that bakes a fresh loaf of bread every morning, then throws away the old one at night. The baker has a small jar of starter dough that never runs out—each day he takes a bit, adds flour and water, and makes a new loaf. Over years, the starter slowly weakens and the bread becomes less fluffy. In this paper, the sea squirt's brain is the loaf, the weekly renewal is the baking cycle, and the starter dough is the pool of SOX2+/NOTCH1+/NEUROG1 stem cells that eventually get exhausted with age.
This matters because human brains cannot replace lost neurons after injury or disease. By studying an animal that rebuilds its entire central nervous system weekly, researchers found a pool of stem cells that keeps working for life. Understanding why those cells eventually wear out could one day point toward ways to slow brain aging or repair damage in people.
The abstract does not specify whether the identified stem cell pool exists in other chordates or whether the aging mechanism generalizes beyond Botryllus. It also does not report direct functional tests of the progenitor continuum or quantify how many cycles the stem cells can sustain before exhaustion. The transplantation results are limited to syngeneic grafts, so immune-mediated effects are not addressed.
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Lifelong Invertebrate Chordate Central Nervous System Regeneration is Driven by a Migrating Pool of Conserved Neural Stem Cells program — Chiara Anselmi, Tom Levy, Jiamu “Chester” Yu et al. — bioRxiv — doi:10.64898/2026.09.11.750342
Abstract licence: CC BY
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.