Razazian Mehdi, Bahiraii Sheyda, Jannat Isratul, Tiffner Adéla, Beilhack Georg, Levkau Bodo, Voelkl Jakob, Alesutan Ioana
Institute for Physiology and Pathophysiology, Johannes Kepler University Linz, Krankenhausstrasse 5, 4020, Linz, Austria.
Institute of Biophysics, Johannes Kepler University Linz, Linz, Austria.
Pflugers Arch. 2025 Jun;477(6):815-826. doi: 10.1007/s00424-025-03068-6. Epub 2025 Feb 3.
Medial vascular calcification is common in chronic kidney disease patients and linked to hyperphosphatemia. Upon phosphate exposure, intricate signaling events orchestrate pro-calcific effects in the vasculature mediated by vascular smooth muscle cells (VSMCs). Sphingosine kinase 1 (SPHK1) produces sphingosine-1-phosphate (S1P) and is associated with complex effects in the vascular system. The present study investigated a possible involvement of SPHK1 in VSMC calcification. Experiments were performed in primary human aortic VSMCs under pro-calcific conditions, with pharmacological inhibition or knockdown of SPHK1 or SPNS2 (a lysolipid transporter involved in cellular S1P export), as well as in Sphk1-deficient and wild-type mice treated with cholecalciferol. In VSMCs, SPHK1 expression was up-regulated by pro-calcific conditions. Calcification medium up-regulated osteogenic marker mRNA expression and activity as well as calcification of VSMCs, effects significantly augmented by co-treatment with the SPHK1 inhibitor SK1-IN-1. SK1-IN-1 alone was sufficient to up-regulate osteogenic signaling in VSMCs during control conditions. Similarly, the SPHK1 inhibitor PF-543 and SPHK1 knockdown up-regulated osteogenic signaling in VSMCs and aggravated VSMC calcification. In contrast, co-treatment with the SPNS2 inhibitor SLF1081851 suppressed osteogenic signaling and calcification of VSMCs, effects abolished by silencing of SPHK1. In addition, Sphk1 deficiency aggravated vascular calcification and aortic osteogenic marker expression in mice after cholecalciferol overload. In conclusion, SPHK1 inhibition, knockdown, or deficiency aggravates vascular pro-calcific signaling and calcification. The reduced calcification after inhibition of S1P export suggests a possible involvement of intracellular S1P, but further studies are required to elucidate the complex roles of SPHKs and S1P signaling in calcifying VSMCs.
血管内侧钙化在慢性肾病患者中很常见，且与高磷血症有关。在接触磷酸盐后，复杂的信号事件会在血管平滑肌细胞（VSMC）介导下在脉管系统中协调促钙化作用。鞘氨醇激酶1（SPHK1）产生1-磷酸鞘氨醇（S1P），并与血管系统中的复杂效应相关。本研究调查了SPHK1在VSMC钙化中可能的作用。在促钙化条件下，对原代人主动脉VSMC进行实验，使用药物抑制或敲低SPHK1或SPNS2（一种参与细胞内S1P输出的溶血磷脂转运蛋白），以及在用胆钙化醇处理的Sphk1基因缺陷型和野生型小鼠中进行实验。在VSMC中，促钙化条件会使SPHK1表达上调。钙化培养基会使成骨标志物mRNA表达和活性以及VSMC钙化上调，与SPHK1抑制剂SK1-IN-1共同处理会显著增强这些效应。单独使用SK1-IN-1就足以在对照条件下上调VSMC中的成骨信号。同样，SPHK1抑制剂PF-543和SPHK1敲低会上调VSMC中的成骨信号并加重VSMC钙化。相反，与SPNS2抑制剂SLF1081851共同处理会抑制VSMC的成骨信号和钙化，而SPHK1沉默会消除这些效应。此外，Sphk1基因缺陷会加重胆钙化醇过载后小鼠的血管钙化和主动脉成骨标志物表达。总之，抑制、敲低或缺乏SPHK1会加重血管促钙化信号和钙化。抑制S1P输出后钙化减少表明细胞内S1P可能参与其中，但需要进一步研究来阐明SPHKs和S1P信号在钙化VSMC中的复杂作用。
