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The research team investigated the four extracellular matrix proteins Brevican, Neurocan, Tenascin-C and Tenascin-R, which occur in the cell environment of nerve cells of the retina. “Their precise role in the retina has not yet been sufficiently investigated,” explains Jacqueline Reinhard-Recht. The researchers therefore studied the visual function of so-called knockout mice, which were genetically modified in such a way that their bodies could not produce the four mentioned proteins.
Through electroretinogram analyses, the research team was able to show that rod photoreceptors and bipolar cells in the knockout mice exhibit functional deficits in visual processing. “Interestingly, we were also able to find significant limitations in visual movement processing in the knockout mice compared to control animals,” says Jacqueline Reinhard-Recht. Mice lacking only the proteins tenascin-C or tenascin-R also display losses in visual motion processing, but much weaker. “This shows that the cumulative loss of four matrix proteins reinforces optomotor limitations,” says the researcher.
Matrix remodeling and imbalance in synaptic signaling
Studies on the retina of knockout mice also revealed changes in various matrix molecules and synapses. “In particular, there was an imbalance of inhibitory and excitatory synapses,” says Jacqueline Reinhard-Recht. “Overall, the research data indicate that the four matrix proteins Brevican, Neurocan, Tenascin-C and Tenascin-R are important modulators of synaptic signaling in the retina.”
“The research data contribute to a much better understanding of the complex molecular mechanisms of visual processing. In the future, these findings could offer new approaches for the development of therapeutic interventions for visual function disorders.”