19-P016 Investigation of the immuno-response and signaling pathway in Xenopus embryonic wound healing

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MECHANISMS OF DEVELOPMENT

1 2 6 (2 0 0 9) S2 9 1–S 30 4

Our experiments demonstrated that blastema cells do not

its expression during the growth phase of juvenile fins, indicating

acquire pluripotency since none of the grafts generated progeny that

that the activation of the smp gene is associated with a transcrip-

contributed to all limb tissues. Although we saw some relaxation of

tional program that is different from that used for the developmen-

lineage boundaries towards developmentally related lineages, the

tal outgrowth of larval and juvenile fins. Morpholino knockdown of

final fate of GFP+ blastema cells strongly reflected their origin.

smp significantly reduced regenerative outgrowth by decreasing cell proliferation as measured by BrdU incorporation and histone-

doi:10.1016/j.mod.2009.06.803

3 phosphorylation. In addition, smp knockdown increased the expression of msxb, msxc, and shh, suggesting that loss of smp de-repressed genes associated with patterning of the regenerating

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tissues. In accordance, loss of smp resulted in the formation of

Investigation of the immuno-response and signaling pathway in

ectopic bone. Taken together, these data indicate a requirement

Xenopus embryonic wound healing

for smp in fin regeneration through control of cell proliferation,

Jingjing Li

for the regulation of specific genes and for proper patterning.

Healing Foundation Centre, The University of Manchester, Manchester,

doi:10.1016/j.mod.2009.06.805

United Kingdom Wound healing is a series of complex events to heal and regenerate epidermal and dermal tissues after injury. Adults often heal their wounds with scars, while embryos can accomplish this process perfectly, without scars. Previous studies have provided some comparisons between adult and embryonic wound healings; however, details in the inflammatory phase of

19-P018 Notch signalling in colonic epithelial cells: Potential roles in inflammatory bowel disease and tissue repair David Qualtrough, Phil Rees, Massimo Pignatelli University of Bristol, Bristol, United Kingdom

wound healing, which is believed to be a main reason for scarring, still remain unknown. Based on our microarray results in

Notch signalling is required for stem cell maintenance in the

Xenopus wound healing and regeneration, I have identified some

intestinal epithelium and directs cells toward the absorptive line-

interesting genes that are up-regulated or phosphorylated by

age upon differentiation. Its role in intestinal disease is unclear.

wounding. They may responsible for the cell activation, wound

Inflammatory bowel disease (IBD) defines a set of incurable and

closure and tissue remodeling at the wound site, or the inflam-

debilitating illnesses which afflict around 2.2 million people

matory cell recruitment to the wound. My later research will

across Europe. Acute inflammation in IBD can destroy the epithe-

focus on the specific functions of these candidate genes and their

lial barrier and remission requires both reduced inflammation

signaling pathways, and try to determine whether they attribute

and adequate repair of the mucosa.

to the scarless wound healing in embryos. doi:10.1016/j.mod.2009.06.804

Tissue repair is a two-stage process consisting of a period of ‘restitution’ where epithelium at the edge of a wound flattens and migrates across the denuded area to reconstitute the epithelial barrier. Following restitution, regeneration involves rapid cell proliferation and differentiation as well as reconstruction of the

19-P017 Simplet controls cell proliferation and gene transcription during

three-dimensional tissue structure. Using immunohistochemistry we have demonstrated an up-

zebrafish caudal fin regeneration

regulation of Notch-1 expression in IBD compared with normal

Caghan Kizil1, Georg Otto1, Robert Geisler1, Christiane Nu¨ssleinVolhard1, Christopher Antos1,2

tissue. Foci of Notch expression was observed in flattened cells

1

Max-Planck Institut fu¨r Entwicklungsbiologie, Tu¨bingen, Germany

2

Center for Regenerative Therapies Dresden/Technische Universita¨t

Dresden, Dresden, Germany

undergoing restitution and in areas of regeneration. These data suggest an altered role for Notch in achieving remission in IBD. Furthermore, we have investigated the effects of 5-amino salicylate (widely used to treat IBD), and the dietary factor sodium butyrate on Notch expression and activity in vitro. Butyrate leads to rapid and sustained down regulation of Notch, whereas low

Epimorphic regeneration of new tissue requires initiating and

doses of 5-ASA stimulate Notch expression and activity. These

controlling extensive cell proliferation after partial loss of an organ

drug treatments also produce converse effects on cell motility,

or appendage. It is unclear what the molecular determinants are

which is vital for wound closure.

that coordinate cell proliferation with patterning of the tissues during tissue regeneration. We found that fam53b/simplet (smp) regu-

Taken together these data imply a vital role for Notch signalling in IBD and intestinal wound repair.

lates both cell proliferation and the transcription of specific genes that are associated with tissue patterning. In situ hybridization

doi:10.1016/j.mod.2009.06.806

and quantitative RT-PCR experiments showed that amputation of zebrafish hearts and fins resulted in expression of the smp gene. In regenerating adult fins, we observed smp expression in the distal mesenchyme which later expanded to the basal layers of the distal

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epidermis and distal tip epithelium. While we observed significant

Retinoic acid signaling in vertebrate appendage regeneration

up-regulation of the gene in regenerating tissues, we did not detect

Nicola Blum, Gerrit Begemann