Molecular Mechanisms of Retina Regeneration in Chickens

Oxford, OH -

Degeneration of the retina is a significant problem associated with several diseases that cause blindness, such as macular degeneration. In a recent paper (Haynes et al. BMP signaling mediates stem/progenitor cell-induced retina regeneration. Proc Natl Acad Sci U S A. 2007 Dec 14) the investigation of molecular signals associated wtih regeneration of the retina was performed.

The model system used was embyronic chicks since these have the capability of regeneration after retinectomy.

The investigators demonstrated that signalling of bone morphogenic protein is both necessary and sufficient for retinal regeneration. Interestingly the actions of the bone morphogenic protein pathway are divided into two phases.

The first phase occurs three days after the retinectomy and is associated with activation of SMAD and fibroblast growth factor signaling by the Mitogen Activated Protein (MAP) kinase.

The second phase occurs at the seventh day after the retinectomy in which apoptosis occurs after p38 activation and inhibition of the FGF signaling occurs by the MAPK and AKT pathways. Interestingly if one inhibits p38 then futher regeneration can be promoted.

This inhibition of p38 for regeneration is reminiscent of patent in which p38 inhibition if covered as a method of accelerating formation of new bone.