Reese Laurine, Niepmann Sven Thomas, Düsing Philip, Hänschke Lea, Beiert Thomas, Zimmer Sebastian, Nickenig Georg, Bauer Reinhard, Jansen Felix, Zietzer Andreas
Department of Internal Medicine II, University Hospital Bonn, University of Bonn, Bonn, Germany.
Life & Medical Sciences Institute (LIMES), Genetics & Molecular Physiology, University of Bonn, Bonn, Germany.
Acta Physiol (Oxf). 2024 May;240(5):e14140. doi: 10.1111/apha.14140. Epub 2024 Mar 28.
Inflammation and calcification are hallmarks in the development of aortic valve stenosis (AVS). Ceramides mediate inflammation and calcification in the vascular tissue. The highly abundant d18:1,16:0 ceramide (C16) has been linked to increased cardiovascular mortality and obesity. In this study, we investigate the role of ceramide synthase 5 (CerS5), a critical enzyme for C16 ceramide synthesis, in the development of AVS, particularly in conjunction with a high-fat/high-cholesterol diet (Western diet, WD).
We used wild-type (WT) and CerS5 mice on WD or normal chow in a wire injury model. We measured the peak velocity to determine AVS development and performed histological analysis of the aortic valve area, immune cell infiltration (CD68 staining), and calcification (von Kossa). In vitro experiments involved measuring the calcification of human aortic valvular interstitial cells (VICs) and evaluating cytokine release from THP-1 cells, a human leukemia monocytic-like cell line, following CerS5 knockdown.
CerS5 mice showed a reduced peak velocity compared to WT only in the experiment with WD. Likewise, we observed reduced immune cell infiltration and calcification in the aortic valve of CerS5 mice, but only on WD. In vitro, calcification was reduced after knockdown of CerS5 in VICs, while THP-1 cells exhibited a decreased inflammatory response following CerS5 knockdown.
We conclude that CerS5 is an important mediator for the development of AVS in mice on WD and regulates critical pathophysiological hallmarks of AVS formation. CerS5 is therefore an interesting target for pharmacological therapy and merits further investigation.
炎症和钙化是主动脉瓣狭窄（AVS）发展过程中的标志。神经酰胺介导血管组织中的炎症和钙化。高度丰富的d18:1,16:0神经酰胺（C16）与心血管死亡率增加和肥胖有关。在本研究中，我们调查了神经酰胺合酶5（CerS5），一种C16神经酰胺合成的关键酶，在AVS发展中的作用，特别是与高脂/高胆固醇饮食（西方饮食，WD）相结合时的作用。
我们在钢丝损伤模型中使用了喂食WD或正常食物的野生型（WT）和CerS5基因敲除小鼠。我们测量峰值速度以确定AVS的发展，并对主动脉瓣区域进行组织学分析、免疫细胞浸润（CD68染色）和钙化（冯·科萨染色）。体外实验包括测量人主动脉瓣间质细胞（VICs）的钙化，并在敲低CerS5后评估人类白血病单核细胞样细胞系THP-1细胞的细胞因子释放。
仅在WD实验中，CerS5基因敲除小鼠的峰值速度低于WT小鼠。同样，我们观察到CerS5基因敲除小鼠主动脉瓣中的免疫细胞浸润和钙化减少，但仅在WD条件下。在体外，VICs中敲低CerS5后钙化减少，而THP-1细胞在敲低CerS5后炎症反应降低。
我们得出结论，CerS5是WD喂养小鼠AVS发展的重要介质，并调节AVS形成的关键病理生理标志。因此，CerS5是药物治疗的一个有吸引力的靶点，值得进一步研究。
