心血管疾病(CVDs),主要由动脉粥样硬化(AS)引起,是全球死亡的主要原因。尽管已有大量的研究试图揭示AS的分子机制,潜在的机制尚未完全阐明。根据从基因表达综合(GEO)数据库下载的数据集(GSE132651)分析早期动脉粥样硬化(EAS)中血管内皮细胞(VEC)基因的异常表达谱。我们主要对下调基因(DRGs)进行功能注释分析。我们进一步鉴定了α-N-乙酰氨基葡萄糖苷酶(NAGLU),其中一个DRG,在EAS的进展中发挥了关键作用。NAGLU是降解硫酸乙酰肝素(HS)的关键酶,其缺乏可引起溶酶体积累并导致VECs功能障碍。我们发现,在人脐静脉内皮细胞(HUVEC)中NAGLU的siRNA敲低加重了溶酶体和HS的异常积累。此外,在ApoE-/-小鼠构建的EAS模型中,NAGLU的表达降低。此外,我们还表明肝素结合EGF样生长因子(HB-EGF)蛋白上调,而NAGLU敲低HUVEC可以特异性结合血管内皮生长因子受体2(VEGFR2)并促进其磷酸化,最终激活细胞外信号调节激酶(ERKs)的磷酸化水平。然而,选择性VEGFR2和ERKs抑制剂的应用,SU5614和PD98059,分别可以逆转NAGLU敲低引起的溶酶体贮积异常。这些结果表明HUVEC中NAGLU的下调增加了溶酶体的异常积累,并且可能是诊断EAS的潜在生物标志物。
Cardiovascular diseases (CVDs), predominantly caused by atherosclerosis (AS), are the leading cause of mortality worldwide. Although a great number of previous studies have attempted to reveal the molecular mechanism of AS, the underlying mechanism has not been fully elucidated. The aberrant expression profiling of vascular endothelial cells (VECs) gene in early atherosclerosis (EAS) was analyzed according to the dataset (GSE132651) downloaded from the Gene Expression Omnibus (GEO) database. We primarily performed functional annotation analysis on the downregulated genes (DRGs). We further identified that α-N-acetylglucosaminidase (
NAGLU), one of the DRGs, played a critical role in the progression of EAS. NAGLU is a key enzyme for the degradation of heparan sulfate (HS), and its deficiency could cause lysosomal accumulation and lead to dysfunctions of VECs. We found that siRNA knockdown of
NAGLU in human umbilical vein endothelial cell (HUVEC) aggravated the abnormal accumulation of lysosomes and HS. In addition, the expression of
NAGLU was reduced in the EAS model constructed by ApoE -/- mice. Furthermore, we also showed that heparin-binding EGF-like growth factor (HB-EGF) protein was upregulated while
NAGLU knockdown in HUVEC could specifically bind to vascular endothelial growth factor receptor 2 (VEGFR2) and promote its phosphorylation, ultimately activating the phosphorylation levels of extracellular signal-regulated kinases (ERKs). However, the application of selective VEGFR2 and ERKs inhibitors, SU5614 and PD98059, respectively, could reverse the abnormal lysosomal storage caused by NAGLU knockdown. These results indicated that downregulation of
NAGLU in HUVEC increases the abnormal accumulation of lysosomes and may be a potential biomarker for the diagnosis of EAS.