Faulty Molecular Master Switch May Contribute to AMD

A study published in eLife suggests a signaling pathway governed by transforming growth factor beta (TGF-beta) could play a role in the progression of age-related macular degeneration (AMD), reports ScienceDaily . The interruption of TGF-beta signals to immune microglia induces the cells into an activated, inflammatory state, and damages the retina in ways similar to cellular effects seen in AMD. The researchers engineered genetically modified mice in which the microglial cells' ability to detect TGF-beta could be repressed. The cells immediately reconfigured, moved to incorrect locations, and started proliferating while also decreasing their expression of sensory proteins. Another group of retinal support cells, Müller glia, became distressed, causing retinal neurons to fail and die. Furthermore, abnormal microglia worsened the growth of new blood vessels in an AMD model. The implication is that microglia and TGF-beta signaling may help fuel disease progression in humans.