Blocking matrix metalloproteinase-mediated syndecan-4 shedding restores the endothelial glycocalyx and glomerular fi ltration barrier function in early diabetic kidney disease
Blocking matrix metalloproteinase-mediated syndecan-4 shedding restores the endothelial glycocalyx and glomerular fi ltration barrier function in early diabetic kidney disease
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DOI：
10.1016/j.kint.2019.09.035
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发表时间：
2020-05-01
影响因子：
19.6
通讯作者：
Satchell, Simon C.
中科院分区：
文献类型：
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作者：
Ramnath, Raina D.;Butler, Matthew J.;Satchell, Simon C.
内皮糖萼是肾小球滤过屏障的关键组成部分。我们已经证明基质金属蛋白酶（MMP）介导的多配体蛋白聚糖4脱落是体外肾小球内皮糖萼损伤的一种机制，导致白蛋白通透性增加。在这里，我们试图通过研究链脲佐菌素诱导的DBA 2/J小鼠1型糖尿病来确定这种机制在早期糖尿病肾病中是否重要。糖尿病小鼠出现蛋白尿，肾小球白蛋白通透性增加，内皮糖萼损伤。在离体肾小球和流式细胞术分选的肾小球内皮细胞中，发现多配体蛋白聚糖4 mRNA表达上调。与此相反，肾小球内皮细胞腔表面syndecan 4和Marasmium oreades凝集素标记测量减少糖尿病小鼠。肾小球中syndecan 4蛋白表达明显降低，而血浆和尿液中syndecan 4蛋白表达明显升高，提示syndecan 4的脱落，肾小球中MMP-2、9和14 mRNA表达上调，提示肾小球糖萼损伤和蛋白尿的可能机制。因此，我们详细描述了MMP-2和MMP-9的活性，发现肾皮质、血浆和尿液中MMP-2和MMP-9的活性显著增加。在糖尿病诱导后6周开始用MMP-2/9抑制剂I治疗21天，恢复了内皮糖萼的深度和覆盖度，并减弱了糖尿病诱导的白蛋白尿，降低了肾小球白蛋白渗透性。MMP抑制剂治疗显着衰减肾小球内皮细胞和血浆多配体蛋白聚糖4脱落和抑制血浆MMP活性。因此，我们的研究证实了基质金属蛋白酶在早期糖尿病的内皮糖萼损伤和蛋白尿中的重要性，并证明了这一途径是适合于治疗干预。因此，通过MMP抑制来靶向糖萼保护的治疗可能对糖尿病肾病有益。
The endothelial glycocalyx is a key component of the glomerular filtration barrier. We have shown that matrix metalloproteinase (MMP)-mediated syndecan 4 shedding is a mechanism of glomerular endothelial glycocalyx damagein vitro, resulting in increased albumin permeability. Here we sought to determine whether this mechanism is important in early diabetic kidney disease, by studying streptozotocin-induced type 1 diabetes in DBA2/J mice. Diabetic mice were albuminuric, had increased glomerular albumin permeability and endothelial glycocalyx damage. Syndecan 4 mRNA expression was found to be upregulated in isolated glomeruli and in flow cytometry-sorted glomerular endothelial cells. In contrast, glomerular endothelial luminal surface syndecan 4 and Marasmium oreades agglutinin lectin labelling measurements were reduced in the diabetic mice. Similarly, syndecan 4 protein expression was significantly decreased in isolated glomeruli but increased in plasma and urine, suggesting syndecan 4 shedding.Mmp-2, 9and14mRNA expression were upregulated in isolated glomeruli, suggesting a possible mechanism of glycocalyx damage and albuminuria. We therefore characterised in detail the activity of MMP-2 and 9 and found significant increases in kidney cortex, plasma and urine. Treatment with MMP-2/9 inhibitor I for 21 days, started six weeks after diabetes induction, restored endothelial glycocalyx depth and coverage and attenuated diabetes-induced albuminuria and reduced glomerular albumin permeability. MMP inhibitor treatment significantly attenuated glomerular endothelial and plasma syndecan 4 shedding and inhibited plasma MMP activity. Thus, our studies confirm the importance of MMPs in endothelial glycocalyx damage and albuminuria in early diabetes and demonstrate that this pathway is amenable to therapeutic intervention. Hence, treatments targeted at glycocalyx protection by MMP inhibition may be of benefit in diabetic kidney disease.