Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA.
Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA; Roduebush Veterans Affairs Medical Center, Indianapolis, Indiana, USA.
Kidney Int. 2018 Feb;93(2):343-354. doi: 10.1016/j.kint.2017.07.019. Epub 2017 Oct 9.
In patients with chronic kidney and end-stage renal diseases, the major risk factor for progression of arterial calcification is the presence of existing (baseline) calcification. Here, we tested whether calcification of arteries is extended from calcified vascular smooth muscle cells (VSMCs) to adjacent normal cells by matrix vesicle-induced alteration of cell signaling. Matrix vesicles isolated from VSMC of rats with chronic kidney disease were co-cultured with VSMCs from normal littermates. Endocytosis of vesicles by recipient cells was confirmed by confocal microscopy. The addition of cellular matrix vesicles with characteristics of exosomes and low fetuin-A content enhanced the calcification of recipient VSMC. Further, only cellular-derived matrix vesicles induced an increase in intracellular calcium ion concentration, NOX1 (NADPH oxidase) and the anti-oxidant superoxide dismutase-2 in recipient normal VSMC. The increase in intracellular calcium ion concentration was due to release from endoplasmic reticulum and partially attributed to the activation of both NOX1 and mitogen-activated protein kinase (MEK1 and Erk1/2) signaling, since inhibiting both pathways blocked the increase in intracellular calcium ion in recipient VSMC. In contrast, matrix vesicles isolated from the media had no effect on the intracellular calcium ion concentration or MEK1 signaling, and did not induce calcification. However, media matrix vesicles did increase Erk1/2, although not to the level of cellular matrix vesicles, and NOX1 expression. Blockade of NOX activity further inhibited the cellular matrix vesicle-induced accelerated calcification of recipient VSMC, suggesting a potential therapeutic role of such inhibition. Thus, addition of cellular-derived matrix vesicles from calcifying VSMC can accelerate calcification by inducing cell signaling changes and phenotypic alteration of recipient VSMC.
在患有慢性肾脏和终末期肾病的患者中，动脉钙化进展的主要危险因素是存在现有（基线）钙化。在这里，我们通过基质小泡诱导的细胞信号改变来测试动脉钙化是否从钙化的血管平滑肌细胞（VSMC）扩展到相邻的正常细胞。从慢性肾脏病大鼠的 VSMC 中分离的基质小泡与正常同窝仔的 VSMC 共培养。通过共聚焦显微镜证实了受者细胞对小泡的内吞作用。具有外泌体特征和低胎球蛋白-A 含量的细胞基质小泡的添加增强了受者 VSMC 的钙化。此外，只有细胞来源的基质小泡诱导受者正常 VSMC 中细胞内钙离子浓度、NOX1（NADPH 氧化酶）和抗氧化剂超氧化物歧化酶-2 的增加。细胞内钙离子浓度的增加是由于内质网的释放，部分归因于 NOX1 和丝裂原活化蛋白激酶（MEK1 和 Erk1/2）信号的激活，因为抑制这两条途径可阻断受者 VSMC 中细胞内钙离子的增加。相比之下，来自培养基的基质小泡对细胞内钙离子浓度或 MEK1 信号没有影响，也不会诱导钙化。然而，培养基基质小泡确实增加了 Erk1/2，尽管不如细胞基质小泡，但增加了 NOX1 的表达。NOX 活性的阻断进一步抑制了细胞基质小泡诱导的受者 VSMC 的加速钙化，表明这种抑制具有潜在的治疗作用。因此，添加来自钙化 VSMC 的细胞衍生基质小泡可以通过诱导细胞信号变化和受者 VSMC 的表型改变来加速钙化。
