Targeting BACE1 to restore functional angiogenesis in type 2 diabetes
Targeting BACE1 to restore functional angiogenesis in type 2 diabetes
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靶向 BACE1 恢复 2 型糖尿病的功能性血管生成
DOI：
10.1093/cvr/cvac066.177
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发表时间：
2022
影响因子：
10.8
通讯作者：
Clavane E
中科院分区：
文献类型：
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作者：
Clavane E
资金来源类型：基金会。主要资金来源：背景β-位点淀粉样前体蛋白（APP）裂解酶1（BACE1）是一种跨膜淀粉样蛋白酶，在阿尔茨海默病（AD）的病理生理学中，其对淀粉样斑块形成的贡献是众所周知的[1]。进一步的研究表明BACE1在血管稳态中的作用[2，3]，并显示其蛋白水解切割各种血管生成信号传导因子，包括VEGF受体1（VEGFR1）[2]、NOTCH配体[4]和胰岛素受体[5]。与AD相似，BACE1活性在2型糖尿病模型中升高[5]，表明其对糖尿病相关并发症的异常血管生长特征的贡献的潜在作用。目的2型糖尿病显著增加个体发生微血管并发症和随后的下肢截肢的风险[6]。因此，确定新的作用BACE1在血管生成失调将有助于未来的生物医学干预措施在这一领域的进展。MethodsRetinal染色和纤维蛋白凝胶血管生成测定被用来确定BACE1在血管生长中的作用，在体内和体外，分别。用IsolectinB4-Alexa488染色BACE1-/-和野生型（WT）小鼠中发育中的视网膜血管的内皮，并使用共聚焦显微镜成像。使用纤维蛋白凝胶血管生成测定法进一步分析了用或不用高度特异性BACE1抑制剂处理或转染以过表达BACE1的人脐静脉内皮细胞（HUVEC）的血栓形成。结果与野生型小鼠相比，BACE 1-/-小鼠视网膜分支点、血管面积和丝状伪足数量均增加。此外，BACE1-/-PEC可降低NOTCH1信号（26.73% ± 14.15，P = 0.05）和可溶性Jagged-1蛋白（28.48% ± 14.61，P =<0.05）。与未处理的细胞相比，用BACE1抑制剂处理的HUVECs具有增加的发芽（18.70% ± 5.92，P =<0.05）以及增加的eNOS（83% ± 22，P =<0.05）和Akt（85.5% ± 9.24，P = NS）磷酸化。BACE1过表达的HUVECs出芽率降低（35.22% ± 7.34，P =<0.01），而NOTCH1信号通路增加（23.4% ± 2.42，P = 0.01）。这为BACE1抑制剂提供了一个潜在的治疗目的，以前曾被用于治疗AD，使2型糖尿病患者的BACE1水平正常化，并预防相关的微血管并发症。
Funding AcknowledgementsType of funding sources: Foundation. Main funding source(s): British Heart FoundationBritish Microcirculation and Vascular Biology SocietyBackgroundβ-site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1) is a transmembrane aspartyl protease notorious for its contribution to amyloid plaque formation in the pathophysiology of Alzheimer’s disease (AD) [1]. Further research has suggested a role for BACE1 in vascular homeostasis [2,3] and has shown that it proteolytically cleaves various angiogenic signalling factors including VEGF receptor 1 (VEGFR1) [2], NOTCH ligands [4] and the insulin receptor [5]. Similar to AD, BACE1 activity is elevated in models of type 2 diabetes [5], suggesting a potential role for its contribution to aberrant vessel growth characteristic of diabetes-related complications.PurposeType 2 diabetes dramatically increases an individual's risk of developing microvascular complications and consequent lower limb amputations [6]. Therefore, identifying novel roles for BACE1 in angiogenic dysregulation will aid progression of future biomedical interventions in this field.MethodsRetinal staining and the fibrin gel angiogenesis assay were used to identify a role for BACE1 in vessel growth in vivo and in vitro, respectively. Endothelium of the developing retinal vasculature in BACE1-/- and wild type (WT) mice was stained with IsolectinB4-Alexa488 and imaged using confocal microscopy. Sprout formation was further analysed using the fibrin gel angiogenesis assay with human umbilical vein endothelial cells (HUVECs) treated with or without a highly specific BACE1 inhibitor or transfected to over-express BACE1. Primary isolated pulmonary endothelial cells (PECs) were isolated from BACE1-/- and wild type control mice prior to Western blots, and real-time PCR.ResultsBACE1-/- retinas had increased branch points, vasculature area and quantity of filopodia compared to WT mice. Moreover, BACE1-/- PECs had reduced NOTCH1 signalling (26.73% ± 14.15, P=0.05) and soluble Jagged-1 protein (28.48% ± 14.61, P=<0.05). HUVECs treated with a BACE1 inhibitor had increased sprouting (18.70%± 5.92, P=<0.05) as well as increased phosphorylation of eNOS (83% ± 22, P=<0.05) and Akt (85.5% ± 9.24, P=NS) compared to untreated cells. Moreover, HUVECs transfected to over-express BACE1 had decreased sprouting (35.22% ± 7.34, P=<0.01) and increased NOTCH1 signalling (23.4% ± 2.42, P=0.01).ConclusionOur findings indicate a role of BACE1 in negatively regulating angiogenesis, possibly via NOTCH1 or Akt/eNOS/NO signalling. This provides a potential therapeutic purpose for BACE1 inhibitors, previously trialled to treat AD, in normalising BACE1 levels in individuals with type 2 diabetes and preventing associated microvascular complications.