Univ Lyon, CarMeN Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, 69500 Bron, France.
Hospices Civils de Lyon, Hôpital Louis Pradel, Services d'Explorations Fonctionnelles Cardiovasculaires et CIC de Lyon, 69394 Lyon, France.
Cells. 2023 Sep 20;12(18):2322. doi: 10.3390/cells12182322.
The Ca release in microdomains formed by intercompartmental contacts, such as mitochondria-associated endoplasmic reticulum membranes (MAMs), encodes a signal that contributes to Ca homeostasis and cell fate control. However, the composition and function of MAMs remain to be fully defined. Here, we focused on the transient receptor potential vanilloid 1 (TRPV1), a Ca-permeable ion channel and a polymodal nociceptor. We found TRPV1 channels in the reticular membrane, including some at MAMs, in a rat cardiomyoblast cell line (SV40-transformed H9c2) by Western blotting, immunostaining, cell fractionation, and proximity ligation assay. We used chemical and genetic probes to perform Ca imaging in four cellular compartments: the endoplasmic reticulum (ER), cytoplasm, mitochondrial matrix, and mitochondrial surface. Our results showed that the ER Ca released through TRPV1 channels is detected at the mitochondrial outer membrane and transferred to the mitochondria. Finally, we observed that prolonged TRPV1 modulation for 30 min alters the intracellular Ca equilibrium and influences the MAM structure or the hypoxia/reoxygenation-induced cell death. Thus, our study provides the first evidence that TRPV1 channels contribute to MAM Ca exchanges.
在由细胞间接触形成的微区（如线粒体相关内质网膜（MAMs））中释放 Ca，编码了一种有助于 Ca 稳态和细胞命运控制的信号。然而，MAMs 的组成和功能仍有待充分定义。在这里，我们专注于瞬时受体电位香草醛 1（TRPV1），一种 Ca 通透性离子通道和多模式伤害感受器。我们通过 Western blot、免疫染色、细胞分级分离和邻近连接分析，在大鼠心肌细胞系（SV40 转化的 H9c2）的网状膜中发现了 TRPV1 通道，包括一些位于 MAMs 中的 TRPV1 通道。我们使用化学和遗传探针在四个细胞区室（内质网（ER）、细胞质、线粒体基质和线粒体表面）进行 Ca 成像。我们的结果表明，通过 TRPV1 通道释放的 ER Ca 可在线粒体外膜检测到，并转移到线粒体。最后，我们观察到 TRPV1 长达 30 分钟的持续调节会改变细胞内 Ca 平衡，并影响 MAM 结构或缺氧/复氧诱导的细胞死亡。因此，我们的研究首次提供了证据，表明 TRPV1 通道有助于 MAM Ca 交换。
