Department of Surgery, University of Wisconsin, Madison, WI 53705, USA.
Department of Surgery, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA.
Genes (Basel). 2022 Dec 16;13(12):2386. doi: 10.3390/genes13122386.
The structurally and genetically distinct sigma-1 receptor (S1R) and sigma-2 receptor (S2R) comprise a unique class of drug binding sites. Their alleles are associated with human diseases involving neuronal systems, such as age-related macular degeneration (AMD) characterized by photoreceptor and retinal pigment epithelium (RPE) atrophy. Previous studies have suggested neuroprotective benefits for the brain and retina from pharmacological modulation of S1R and/or S2R. However, the effect of such modulation on AMD pathology remains underexplored. Here, we evaluated S1R- or S2R-selective modulation in an AMD-related model of -/--/- mice with a disrupted visual cycle that predisposes RPE and photoreceptors to illumination-induced damage. For S1R modulation, we used (+)-pentazocine, which is a high-affinity S1R-selective drug. For S2R modulation, we chose CM398, a high-affinity and highly S2R-selective ligand with drug-like properties. -/--/- mice received a single i.p. injection of (+)-pentazocine or CM398 or vehicle 30 min before illumination. Pretreatment with (+)-pentazocine improved electroretinogram a- and b-waves compared to that with vehicle. Consistently, in another AMD-related mouse model induced by tail-vein injected NaIO, S1R genetic ablation aggravated photoreceptor loss. In -/--/- mice, pretreatment with CM398 appeared to partially avert illumination-induced photoreceptor loss and autofluorescent granule formation that signals RPE damage, as revealed by optical coherence tomography. Thus, this study using AMD-related models provides evidence of photoreceptor protection afforded by selective modulation of S1R or S2R.
结构和遗传上不同的 sigma-1 受体(S1R)和 sigma-2 受体(S2R)构成了一类独特的药物结合位点。它们的等位基因与涉及神经元系统的人类疾病有关,例如年龄相关性黄斑变性(AMD),其特征是感光器和视网膜色素上皮(RPE)萎缩。先前的研究表明,通过药理学调节 S1R 和/或 S2R 可以为大脑和视网膜提供神经保护益处。然而,这种调节对 AMD 病理学的影响仍未得到充分探索。在这里,我们在视觉周期中断的 -/--/- 小鼠的 AMD 相关模型中评估了 S1R 或 S2R 的选择性调节,该模型使 RPE 和感光器容易受到光照诱导的损伤。对于 S1R 调节,我们使用了(+)-戊噻嗪,这是一种高亲和力的 S1R 选择性药物。对于 S2R 调节,我们选择了 CM398,这是一种具有药物特性的高亲和力和高度 S2R 选择性配体。-/--/- 小鼠在光照前 30 分钟接受单次腹腔注射(+)-戊噻嗪或 CM398 或载体。与载体相比,(+)-戊噻嗪预处理可改善视网膜电图的 a 波和 b 波。一致地,在另一种由尾静脉注射 NaIO 诱导的 AMD 相关小鼠模型中,S1R 基因缺失加剧了感光器的丧失。在 -/--/- 小鼠中,CM398 的预处理似乎部分避免了光照诱导的感光器丧失和自荧光颗粒形成,这表明 RPE 损伤,如光学相干断层扫描所示。因此,这项使用 AMD 相关模型的研究提供了证据表明,通过选择性调节 S1R 或 S2R 可以保护感光器。