Ball John M, Chen Shan, Li Wei
Retinal Neurophysiology Section, National Eye Institute, NIH, Bethesda, MD 20892, USA.
Sci Adv. 2022 Mar 4;8(9):eabn2070. doi: 10.1126/sciadv.abn2070. Epub 2022 Mar 2.
Mammalian photoreceptors aggregate numerous mitochondria, organelles chiefly for energy production, in the ellipsoid region immediately adjacent to the light-sensitive outer segment to support the high metabolic demands of phototransduction. However, these complex, lipid-rich organelles are also poised to affect light passage into the outer segment. Here, we show, via live imaging and simulations, that despite this risk of light scattering or absorption, these tightly packed mitochondria "focus" light for entry into the outer segment and that mitochondrial remodeling affects such light concentration. This "microlens"-like feature of cone mitochondria delivers light with an angular dependence akin to the Stiles-Crawford effect (SCE), providing a simple explanation for this essential visual phenomenon that improves resolution. This new insight into the optical role of mitochondria is relevant for the interpretation of clinical ophthalmological imaging, lending support for the use of SCE as an early diagnostic tool in retinal disease.
哺乳动物的光感受器在紧邻光敏感外段的椭球体区域聚集了大量线粒体，线粒体主要负责能量产生，以支持光转导过程中对能量的高需求。然而，这些复杂的、富含脂质的细胞器也可能影响光线进入外段。在这里，我们通过实时成像和模拟表明，尽管存在光散射或吸收的风险，但这些紧密排列的线粒体能够“聚焦”光线，使其进入外段，而且线粒体重塑会影响这种光的聚集。锥体细胞线粒体的这种“微透镜”样特征以类似于斯泰尔斯-克劳福德效应（SCE）的角度依赖性来传递光线，为这一提高分辨率的基本视觉现象提供了一个简单的解释。对线粒体光学作用的这一新见解与临床眼科成像的解释相关，支持将SCE用作视网膜疾病的早期诊断工具。
