Stem cells

Developmental origin of a bipotential myocardial and smooth muscle cell precursor in the mammalian heart. Wu, S. M. et al. Cell 22 Nov 2006 (doi: 10.1016/j.cell.2006.10.028)

Multipotent embryonic Isl1+ progenitor cells lead to cardiac, smooth muscle, and endothelial cell diversification. Moretti, A. et al. Cell 22 Nov 2006 (doi: 10.1016/j.cell.2006.10.029)

Cardiac disorders represent one field in which there is currently great interest in the potential of therapeutic strategies based on stem cells, but the identification of the optimal cell types for such strategies is a major challenge. The endothelial, cardiac and smooth muscle cells needed for cardiogenesis have been thought to arise from distinct embryonic precursors. However, these two papers in Cell report multipotent cardiovascular progenitor cells that are capable of developing into two and three of these cell types, respectively, which might be valuable in therapeutic cardiovascular tissue regeneration in disorders such as heart failure.

Nanotechnology

Rare earth nanoparticles prevent retinal degeneration induced by intracellular peroxides. Chen, J. et al. Nature Nanotechnol. 1, 142–150 (2006)

Reactive oxygen intermediates (ROIs) are thought to be important in the pathogenesis of retinal degeneration. Chen et al. tested their hypothesis that engineered cerium oxide nanoparticles that scavenge ROIs might be able to do so within retinal neurons; their data show that these particles prevent increases in intracellular ROI concentrations in vitro and loss of vision due to light-induced degeneration of photoreceptor cells in albino rats. Such particles might therefore represent a new type of therapeutic strategy for various retinal diseases, and also other disorders in which ROIs are involved.

Parkinson's Disease

Activation of tyrosine kinase receptor signaling pathway by rasagiline facilitates neurorescue and restoration of nigrostriatal dopamine neurons in MPTP-induced parkinsonism. Sagi, Y. et al. Neurobiol. Dis. 25, 35–44 (2007)

Developing agents that have the potential to modify or reverse the pathogenesis of Parkinson's disease, rather than just target the symptoms, is a major challenge. Sagi and colleagues investigated the effects of rasagiline — an approved monoamine oxidase (MAO)-B inhibitor that is known to have neuroprotective activities unrelated to its ability to inhibit MAO-B — in the standard MPTP mouse model of Parkinson's disease. They show that rasagiline has neurorescue/neurotrophic activity, and provide several lines of evidence that a mechanism involving induction of neurotrophic factors and activation of the Ras–PI3K–Akt survival pathway is important in this activity.