Suppression of Wnt Signaling and Osteogenic Changes in Vascular Smooth Muscle Cells by Eicosapentaenoic Acid

Abstract

Vascular medial calcification is often observed in patients with arteriosclerosis. It is also associated with systolic hypertension, wide pulse pressure, and fluctuation of blood pressure, which results in cardiovascular events. Eicosapentaenoic acid (EPA) has been shown to suppress vascular calcification in previous animal experiments. We investigated the inhibitory effects of EPA on Wnt signaling, which is one of the important signaling pathways involved in vascular calcification. Intake of food containing 5% EPA resulted in upregulation of the mRNA expression of Klotho, an intrinsic inhibitor of Wnt signaling, in the kidneys of wild-type mice. Expression levels of β-catenin, an intracellular signal transducer in the Wnt signaling pathway, were increased in the aortas of Klotho mutant (kl/kl) mice compared to the levels in the aortas of wild-type mice. Wnt3a or BIO, a GSK-3 inhibitor that activates β-catenin signaling, upregulated mRNA levels of AXIN2 and LEF1, Wnt signaling marker genes, and RUNX2 and BMP4, early osteogenic genes, in human aorta smooth muscle cells. EPA suppressed the upregulation of AXIN2 and BMP4. The effect of EPA was cancelled by T0070907, a PPARγ inhibitor. The results suggested that EPA could suppress vascular calcification via the inhibition of Wnt signaling in osteogenic vascular smooth muscle cells via PPARγ activation.

Signaling pathways involved in vascular smooth muscle cell calcification during hyperphosphatemia

“…Soluble klotho has been suggested to contribute to vascular calcification [ 125 ] and may be able to inhibit the phosphate uptake via PIT1 in VSMCs [ 125 ]. The suggested protective effects of klotho on vascular calcification involve the inhibition of the WNT/β-catenin signaling pathway [ 127 , 128 ]. In addition, both anti- [ 129 ] and pro-calcific [ 130 ] effects of FGF23 were described.…”

“…Similarly, the SGK1/NF-kB osteoinductive pathway may be activated by IL-18 [ 133 ], resulting in aggravation of phosphate-induced VSMCs mineralization [ 133 , 141 ]. Furthermore, together with the NF-kB pathway, WNT/β-catenin signaling may modulate pro-inflammatory signaling cascades in VSMCs in response to hyperphosphatemia [ 127 , 142 , 143 ].…”

A GTPase-activating protein–binding protein (G3BP1)/antiviral protein relay conveys arteriosclerotic Wnt signals in aortic smooth muscle cells

“…4F). In addition to reducing OPN mRNA, G3BP1 "knockdown" reduced the accumulation of Msx2 and LEF1 genes, components of Wnt signaling important to both craniofacial (32,33) and ectopic arterial (6,34) mineralization. Western blot analysis confirmed selective reductions in G3BP1 protein accumulation with G3BP1 siRNA (Fig.…”

Effects of Eicosapentaenoic Acid on Arterial Calcification

“…In human aortic smooth muscle cells, activation of Wnt signaling induces the expression of osteogenic genes [78,108]. EPA suppresses not only the expression of these osteogenic genes but also the expression of Wnt signaling marker genes via upregulation of peroxisome proliferator-activating receptor gamma (PPARγ) [78]. PPARγ activates secreted frizzled-related protein 2 (SFRP2) and counteracts vascular calcification induced by Wnt5a in mice [109].…”

“…PPARγ activates secreted frizzled-related protein 2 (SFRP2) and counteracts vascular calcification induced by Wnt5a in mice [109]. Additionally, EPA upregulates Klotho in the kidney [78].…”