Organelle crosstalk is vital for cellular functions. The propinquity of mitochondria, ER, and plasma membrane promote regulation of multiple functions, which include intracellular Ca²⁺ flux, and cellular biogenesis. Although the purposes of apposing mitochondria and ER have been described, an understanding of altered organelle connectomics related to disease states is emerging. Since inner ear outer hair cell (OHC) degeneration is a common trait of age-related hearing loss, the objective of this study was to investigate whether the structural and functional coupling of mitochondria with subsurface cisternae (SSC) was affected by aging. We applied functional and structural probes to equal numbers of male and female mice with a hearing phenotype akin to human aging. We discovered the polarization of cristae and crista junctions in mitochondria tethered to the SSC in OHCs. Aging was associated with SSC stress and decoupling of mitochondria with the SSC, mitochondrial fission/fusion imbalance, a remarkable reduction in mitochondrial and cytoplasmic Ca²⁺ levels, reduced K⁺-induced Ca²⁺ uptake, and marked plasticity of cristae membranes. A model of structure-based ATP production predicts profound energy stress in older OHCs. This report provides data suggesting that altered membrane organelle connectomics may result in progressive hearing loss.

细胞器串扰对于细胞功能至关重要。线粒体、ER 和质膜的邻近性促进多种功能的调节，包括细胞内 Ca ²⁺通量和细胞生物发生。尽管已经描述了将线粒体和 ER 并列的目的，但对与疾病状态相关的改变的细胞器连接组学的理解正在出现。由于内耳外毛细胞（OHC）变性是与年龄相关的听力损失的常见特征，因此本研究的目的是调查线粒体与地下池（SSC）的结构和功能耦合是否受到衰老的影响。我们将功能和结构探针应用于相同数量的雄性和雌性小鼠，这些小鼠的听力表型类似于人类衰老。我们发现 OHC 中与 SSC 相连的线粒体中嵴和嵴连接处的极化。衰老与SSC应激和线粒体与SSC的解偶联、线粒体裂变/融合失衡、线粒体和细胞质Ca ²⁺水平显着降低、K ⁺诱导的Ca ²⁺吸收减少以及嵴膜的显着可塑性相关。基于结构的 ATP 生成模型预测老年 OHC 中存在严重的能量压力。该报告提供的数据表明膜细胞器连接组学的改变可能导致进行性听力损失。