Retinitis pigmentosa (RP) is often described as a steady, unstoppable loss of the eye’s photoreceptors, the rod and cone cells that allow us to see. But new research from our lab, published on 1.12.2025 in Investigative Ophthalmology & Visual Science, shows that the story is more complex than pure decline.

Using an RP mouse model (P23H/Gnat2−/−), the study suggests that even as rod photoreceptors begin to die, they seem to activate a set of synaptic “survival programs” that attempt to stabilize communication with the rest of the retinal circuit. These changes are not visible through in vivo imaging techniques; instead, our team combined single-cell RNA sequencing, bulk retinal proteomics, and high-resolution immunohistochemistry to capture what happens inside surviving cells.

The findings point to an important pattern: genes and proteins involved in synaptic transmission – particularly components of the SNARE complex and vesicle-release machinery such as SNAP25, SYT1, and STXBP1 – are upregulated in degenerating rods. Even in regions where many rods have already died, the remaining cells continue to express these presynaptic markers, suggesting an active attempt to maintain signaling with downstream neurons.

Why does this matter? Because it reinforces a growing view that retinal degeneration is not just passive cell loss. The retina responds with compensatory, and sometimes maladaptive, remodeling. Understanding these molecular adaptations is crucial for designing therapies that work with the retina’s internal survival mechanisms rather than against them.

In particular, the study provides molecular evidence for a concept that has emerged in recent years: homeostatic plasticity – the brain’s and retina’s natural ability to stabilize function when cells are stressed or lost – may be an untapped therapeutically. If scientists can learn to support or fine-tune these adaptive programs, new treatment strategies could emerge that preserve vision longer, even before gene- or cell-based interventions become widely available.

In short, this research uncovers a subtle but significant truth: the degenerating retina is not giving up, it’s fighting back. By decoding how photoreceptors attempt to preserve their synaptic function, we move one step closer to therapies that can help them succeed.

Read more at: Presynaptic Changes in Mouse Rod Photoreceptors During Early Retinitis Pigmentosa | IOVS | ARVO Journals

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