Neuroprotective Effects of SIRT1 Gene Therapy Protects Stem Cell-Derived Retinal Ganglion Cells from Oxidative Stress
Researchers are exploring whether SIRT1 gene therapy can protect human retinal cells from damage linked to optic neuropathies.
Key findings
- SIRT1 gene therapy improved survival of human induced pluripotent stem cell (iPSC)-derived Retinal Ganglion Cells (RGCs) under oxidative stress
- AAV2-SIRT1 was reliably expressed in RGCs using the SNCG promoter
- Protective effects of SIRT1 were observed at multiple time points (Day 42 and Day 90)
- SIRT1 may be a promising neuroprotection target for optic neuropathies
Neurodegeneration of retinal ganglion cells (RGCs) is a leading cause of irreversible vision loss in optic neuropathies. While previous research in animal models has highlighted the neuroprotective potential of SIRT1 gene therapy, the question remained whether these benefits could be recapitulated in a human cell-based system. A recent study addressed this by investigating the effects of SIRT1 expression in human induced pluripotent stem cell (iPSC)-derived RGCs exposed to oxidative stress.
Researchers began by differentiating RGCs from human induced pluripotent stem cells (iPSCs), using a series of small molecules and peptide modulators. By day 42 of differentiation, more than 80% of the cultured cells expressed Brn3a, a recognized RGC marker, and displayed characteristic morphology of mature RGCs. These features were confirmed through immunostaining for RGC-specific markers Brn3a and RBPMS, along with qPCR analysis, and were maintained up to day 90 in culture.
To investigate neuroprotection, the team used adeno-associated virus serotype 2 (AAV2) to deliver either SIRT1 or GFP (as a control) into the iPSC-derived RGCs. Importantly, gene expression was driven by the SNCG promoter, which is selective for RGCs. An optimized multiplicity of infection (MOI) was used to balance efficient transduction with minimal cell toxicity.
The RGCs were then subjected to oxidative stress, either through exposure to tert-butyl hydroperoxide (TBHP) or by withdrawing growth factors from the culture medium. Cell survival was assessed using the MTT assay. The results showed that SIRT1 expression significantly improved RGC survival compared to control cells, with an approximate 20% increase in viability observed at both day 42 and day 90 timepoints.
These findings support earlier in vivo observations in mouse models, providing additional evidence that SIRT1 could be a promising therapeutic avenue for neuroprotection in optic neuropathies. The study demonstrates that SIRT1 gene therapy can protect human iPSC-derived RGCs from oxidative stress in a controlled in vitro setting. However, while these results are encouraging, further research and ultimately clinical studies will be needed to determine whether these findings translate to effective treatments for vision loss in patients.
Suad Abd Alhadi, David Camacho, Brahim Chaqour, Jacob B. Rossman, Jennifer C. Pham, Kenneth S. Shindler, Ahmara G. Ross, Neuroprotective effects of SIRT1 in human RGCs derived from iPSCs following oxidative stress induction at early and late stages of differentiation, Experimental Eye Research, Volume 259, 2025, 110526, ISSN 0014-4835 https://doi.org/10.1016/j.exer.2025.110526.
