Purpose

Fibrocalcific aortic valve disease (CAVD) is caused by the deposition of calcific nodules in the aortic valve leaflets, resulting in progressive loss of function that ultimately requires surgical intervention. This process is actively mediated by the resident valvular interstitial cells (VICs), which, in response to oxidized lipids, transition from a quiescent to an osteoblast-like state. The purpose of this study was to examine if the ryanodine receptor, an intracellular calcium channel, could be therapeutically targeted to prevent this phenotypic conversion.

Methods

The expression of the ryanodine receptor in porcine aortic VICs was characterized by qRT-PCR and immunofluorescence. Next, the VICs were exposed to lysophosphatidylcholine, an oxidized lipid commonly found in low-density lipoprotein, while the activity of the ryanodine receptor was modulated with ryanodine. The cultures were analyzed for markers of cellular mineralization, alkaline phosphatase activity, proliferation, and apoptosis.

Results

Porcine aortic VICs predominantly express isoform 3 of the ryanodine receptors, and this protein mediates the cellular response to LPC. Exposure to LPC caused elevated intracellular calcium concentration in VICs, raised levels of alkaline phosphatase activity, and increased calcific nodule formation, but these changes were reversed when the activity of the ryanodine receptor was blocked.

Conclusions

Our findings suggest blocking the activity of the ryanodine receptor can attenuate the valvular mineralization caused by LPC. We conclude that oxidized lipids, such as LPC, play an important role in the development and progression of CAVD and that the ryanodine receptor is a promising target for pharmacological intervention.

中文翻译：

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Ryanodine 受体有助于瓣膜间质细胞中溶血磷脂酰胆碱诱导的矿化。

目的

纤维钙化主动脉瓣疾病 (CAVD) 是由主动脉瓣叶中钙化结节沉积引起的，导致功能进行性丧失，最终需要手术干预。这一过程是由常驻瓣膜间质细胞（VIC）主动介导的，这些细胞响应氧化脂质，从静止状态转变为成骨细胞样状态。本研究的目的是检查兰尼碱受体（一种细胞内钙通道）是否可以作为治疗靶点来阻止这种表型转换。

方法

通过 qRT-PCR 和免疫荧光技术对猪主动脉 VIC 中兰尼碱受体的表达进行了表征。接下来，将 VIC 暴露于溶血磷脂酰胆碱（低密度脂蛋白中常见的一种氧化脂质），同时用兰尼碱调节兰尼碱受体的活性。分析培养物的细胞矿化、碱性磷酸酶活性、增殖和凋亡的标志物。

结果

猪主动脉 VIC 主要表达兰尼碱受体亚型 3，该蛋白介导细胞对 LPC 的反应。暴露于 LPC 会导致 VIC 细胞内钙浓度升高、碱性磷酸酶活性水平升高以及钙化结节形成增加，但当兰尼碱受体的活性被阻断时，这些变化会逆转。

结论

我们的研究结果表明，阻断兰尼碱受体的活性可以减弱 LPC 引起的瓣膜矿化。我们得出的结论是，氧化脂质（例如 LPC）在 CAVD 的发生和进展中发挥着重要作用，而兰尼碱受体是药物干预的一个有前景的靶点。