The differential role of Jak/STAT signaling in retinal degeneration.

Retinal degenerative diseases are a major cause of severe visual impairment or blindness in humans. To develop therapeutic strategies it is of particular importance to understand the molecular mechanisms taking place during the progression of the disease. Genes and proteins of the Janus kinase/Signal Transducer and Activator of Transcription (Jak/STAT) signaling pathway have been shown to play an important role in models of retinal degeneration (RD). Here we investigated the expression of additional genes involved in the Jak/STAT pathway in an induced (light exposure) and an inherited (rd1 mouse) model of RD. We show that STAT mRNAs as well as the Jak2/shp-1 pathway are differentially regulated in the two models. In contrast, we show that Jak3 mRNA is upregulated in both, the light damaged and the degenerative retina of the rd1 mouse. This common answer to probably different apoptotic stimuli suggests a prominent role for Jak3 in the damaged retina and could therefore be interesting for further investigations.