| First Author | Wang J | Year | 2017 |
| Journal | Invest Ophthalmol Vis Sci | Volume | 58 |
| Issue | 11 | Pages | 4545-4558 |
| PubMed ID | 28877319 | Mgi Jnum | J:257116 |
| Mgi Id | MGI:6112487 | Doi | 10.1167/iovs.17-21947 |
| Citation | Wang J, et al. (2017) Absence of Sigma 1 Receptor Accelerates Photoreceptor Cell Death in a Murine Model of Retinitis Pigmentosa. Invest Ophthalmol Vis Sci 58(11):4545-4558 |
| abstractText | Purpose: Sigma 1 Receptor (Sig1R) is a novel therapeutic target in neurodegenerative diseases, including retinal disease. Sig1R-/- mice have late-onset retinal degeneration with ganglion cell loss that worsens under stress. Whether Sig1R plays a role in maintaining other retinal neurons is unknown, but was investigated here using rd10 mice, a model of severe photoreceptor degeneration. Methods: Wild-type, rd10, and rd10/Sig1R-/- mice were subjected to ERG and spectral-domain optical coherence tomography (SD-OCT) to assess visual function/structure in situ. Retinas imaged microscopically were subjected to morphometric analysis, immunodetection of cones, and analysis of gliosis. Oxidative and endoplasmic reticulum (ER) stress was evaluated at mRNA/protein levels. Results: Photopic ERG responses were reduced significantly in rd10/Sig1R-/- versus rd10 mice at P28 (31 +/- 6 vs. 56 +/- 7 muV), indicating accelerated cone loss when Sig1R was absent. At P28, SD-OCT revealed reduced retinal thickness in rd10/Sig1R-/- mice (60% of WT) versus rd10 (80% of WT). Morphometric analysis disclosed profound photoreceptor nuclei loss in rd10/Sig1R-/- versus rd10 mice. rd10/Sig1R-/- mice had 35% and 60% fewer photoreceptors, respectively, at P28 and P35, than rd10. Peanut agglutinin cone labeling decreased significantly; gliosis increased significantly in rd10/Sig1R-/- versus rd10 mice. At P21, NRF2 levels increased in rd10/Sig1R-/- mice versus rd10 and downstream antioxidants increased indicating oxidative stress. At P28, ER stress genes/proteins, especially XBP1, a potent transcriptional activator of the unfolded protein response and CHOP, a proapoptotic transcription factor, increased significantly in rd10/Sig1R-/- mice versus rd10. Conclusions: Photoreceptor cell degeneration accelerates and cone function diminishes much earlier in rd10/Sig1R-/- than rd10 mice emphasizing the importance of Sig1R as a modulator of retinal cell survival. |
