Phospholipase D: A new mediator during high phosphate‐induced vascular calcification associated with chronic kidney disease

Abstract

Vascular calcification (VC) is the pathological accumulation of calcium phosphate crystals in one of the layers of blood vessels, leading to loss of elasticity and causing severe calcification in vessels. Medial calcification is mostly seen in patients with chronic kidney disease (CKD) and diabetes. Identification of key enzymes and their actions during calcification will contribute to understand the onset of pathological calcification. Phospholipase D (PLD1, PLD2) is active at the earlier steps of mineralization in osteoblasts and chondrocytes. In this study, we aimed to determine their effects during high-phosphate treatment in mouse vascular smooth muscle cell line MOVAS, in the ex vivo model of the rat aorta, and in the in vivo model of adenine-induced CKD. We observed an early increase in PLD1 gene and protein expression along with the increase in the PLD activity in vascular muscle cell line, during calcification induced by ascorbic acid and β-glycerophosphate. Inhibition of PLD1 by the selective inhibitor VU0155069, or the pan-PLD inhibitor, halopemide, prevented calcification. The mechanism of PLD activation is likely to be protein kinase C (PKC)-independent since bisindolylmaleimide X hydrochloride, a pan-PKC inhibitor, did not affect the PLD activity. In agreement, we found an increase in Pld1 gene expression and PLD activity in aortic explant cultures treated with high phosphate, whereas PLD inhibition by halopemide decreased calcification. Finally, an increase in both Pld1 and Pld2 expression occurred simultaneously with the appearance of VC in a rat model of CKD. Thus, PLD, especially PLD1, promotes VC in the context of CKD and could be an important target for preventing onset or progression of VC.

Research Models for Studying Vascular Calcification

“…Currently, aortic rings from rats and mice are commonly used for studying vessel calcification under various conditions. The stimulation time varies from 3-14 days [6,24,25,28,59,[62][63][64][65]. Although the utilization of aortic rings comes closer to the physiologic setting, a multitude of influencing factors is still lost.…”

A Bioactive Disintegrable Polymer Nanoparticle for Synergistic Vascular Anticalcification

“…While the former is regarded as a potent inhibitor, the latter serves as an inducer for calcium deposition. 47,48 For the treatment, as discussed above, the cells were viable when treated with the PSI-OA NPs up to the tested concentration of 640 μg/mL (3 days of incubation). However, as indicated above, Cur at high concentration (32 μg/mL) was toxic to the cells after 3 days of incubation.…”

Poly(succinimide) nanoparticles as reservoirs for spontaneous and sustained synthesis of poly(aspartic acid) under physiological conditions: potential for vascular calcification therapy and oral drug delivery

“…VSMCs are the main mediator for vascular calcification because they trans-differentiate into osteogenic cells under pathological conditions, facilitating calcium deposition. [32][33][34] A variety of studies have shown that the chelation ability of PASP results in the prevention of calcium precipitation and deposition. 2 Considering these results, we expect that because PASP is spontaneously synthesized by the gradual hydrolysis of PSI NPs, calcification of VSMCs would be prevented.…”

“…7B). 32,33 ALP is a well-known enzyme that catalyzes the hydrolysis of pyrophosphates to inorganic phosphate. While the former is regarded as a potent inhibitor, the latter serves as an inducer for calcium deposition.…”