Posted by Natalie DeWitt for Attila Csordás
The sea squirt can regenerate its whole body from the vasculature. Here Attila Csordás interviews Ayelet Voskoboynik, postdoctoral fellow from the Weissman lab, Stanford University, to tell us how.
Their findings were published in a recent paper, entitled Striving for normality: whole body regeneration through a series of abnormal generations
(FASEB Journal, 2007 May;21(7):1335-44.)
AC: What can a simple chordate, the sea squirt, teach us about regenerative biology?
AV: This chordate has been used by scientists for years as a model system for immunology, developmental biology, aging and more. The lesson in this case comes from observing and manipulating the different developmental programs of Botryllus schlosseri, a colonial marine urochordate, collected from the Monterey Marina (Monterey, CA, USA).
AC: What do your results show about the regeneration of Botryllus schlosseri?
AV: Our study describes a remarkable regeneration phenomenon in a vertebrate ancestor, Botryllus schlosseri. In this animal, the entire body is regenerated from blood vessels. The novelty of our study is the finding that the regeneration occurs over multiple generations of individuals. The animals are initially abnormal, but gradually regain normal patterns, eventually converging (within several generations) into a completely normal animal. This is a novel regenerative/developmental pathway for a whole organism which to our knowledge has not been described before.
AC: In the press release on your paper that was circulated all around the web it was said that: “Findings described in a new study by Stanford scientists may be the first step toward a major revolution in human regenerative medicine—a future where advanced organ damage can be repaired by the body itself.” Truth be told, I haven’t find results calling for human analogies in the article, just a weird and interesting phenomenon– whole body gradual and modular regeneration model from the vasculature in a protochordata. Would you be kind enough to tell me, how the extrapolation to human is possible here, or what may it mean?
AV: I absolutely agree with you, our results don’t call for human analogies. It only establishes the foundation for detailed studies of the cues and mechanisms that may promote reorganization of abnormal tissue and organ structures into a normal body plan in this protochordate. Finding these capabilities in a vertebrate ancestor gives us hope that future studies will disclose some pathways for restoration of lost or compromised organs in this species, and clues to look for such pathways in the vertebrates. We were not responsible for the content of the press release by FASEB, and we would not have made such a sweeping claim. Like all scientists, we hope that our work will eventually have clinical significance, but there is no direct evidence from this publication of imminent translations. We should add that we have learned much about self-nonself recognition in these protochordates that regulate the traffic of stem cells from one individual to another, and that the isolated histocompatibility gene has sequence related genes in mouse and man. Each of these findings cause us to look more closely at such issues in man and mouse.
AC: Which human tissue, organ or organ system will likely benefit from such studies of vascular budding as a regeneration model?
AV: Currently, there is no direct clinical implication for this work. Moreover we can’t tell at this stage if there are any implication for any human tissues. Many diseases and disorders result in abnormal structures. If the cells or genetic pathways involved in Botryllus vascular regenerations have homologues in human vascular associated tissues, we would look for their presence or absence during damage and healing. But that is a long way away and only a first step.
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