Department of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Clinical Geriatrics, Karolinska Institutet, BioClinicum J9:20 Visionsgatan 4, Solna, 171 64, Sweden.
Translational and Clinical Research Institute, Campus for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, NE4 5PL, UK.
Acta Neuropathol Commun. 2023 May 8;11(1):76. doi: 10.1186/s40478-023-01558-1.
Cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is caused by NOTCH3 mutations. Typical CADASIL is characterised by subcortical ischemic strokes due to severe arteriopathy and fibrotic thickening of small arteries. Arteriolar vascular smooth muscle cells (VSMCs) are the key target in CADASIL, but the potential mechanisms involved in their degeneration are still unclear. Focusing on cerebral microvessels in the frontal and anterior temporal lobes and the basal ganglia, we used advanced proteomic and immunohistochemical methods to explore the extent of inflammatory and immune responses in CADASIL subjects compared to similar age normal and other disease controls. There was variable loss of VSMC in medial layers of arteries in white matter as well as the cortex, that could not be distinguished whether NOTCH3 mutations were in the epidermal growth factor (EGFr) domains 1-6 or EGFr7-34. Proteomics of isolated cerebral microvessels showed alterations in several proteins, many associated with endoplasmic reticulum (ER) stress including heat shock proteins. Cerebral vessels with sparsely populated VSMCs also attracted robust accrual of perivascular microglia/macrophages in order CD45 > CD163 > CD68cells, with > 60% of vessel walls exhibiting intercellular adhesion molecule-1 (ICAM-1) immunoreactivity. Functional VSMC cultures bearing the NOTCH3 Arg133Cys mutation showed increased gene expression of the pro-inflammatory cytokine interleukin 6 and ICAM-1 by 16- and 50-fold, respectively. We further found evidence for activation of the alternative pathway of complement. Immunolocalisation of complement Factor B, C3d and C5-9 terminal complex but not C1q was apparent in ~ 70% of cerebral vessels. Increased complement expression was corroborated in > 70% of cultured VSMCs bearing the Arg133Cys mutation independent of N3ECD immunoreactivity. Our observations suggest that ER stress and other cellular features associated with arteriolar VSMC damage instigate robust localized inflammatory and immune responses in CADASIL. Our study has important implications for immunomodulation approaches to counter the characteristic arteriopathy of CADASIL.
伴有皮质下梗死和白质脑病的脑常染色体显性动脉病（CADASIL）是由 NOTCH3 突变引起的。典型的 CADASIL 特征是由于严重的小动脉动脉病和纤维化增厚导致皮质下缺血性中风。小动脉血管平滑肌细胞（VSMC）是 CADASIL 的关键靶标，但涉及它们退化的潜在机制仍不清楚。我们专注于额前和颞前叶以及基底节的脑微血管，使用先进的蛋白质组学和免疫组织化学方法，比较 CADASIL 患者与年龄相似的正常人和其他疾病对照之间的炎症和免疫反应程度。在白质和皮质中，动脉中层的 VSMC 有不同程度的丢失，无法区分 NOTCH3 突变是否位于表皮生长因子（EGFr）域 1-6 或 EGFr7-34。分离的脑微血管的蛋白质组学显示，许多与内质网（ER）应激相关的蛋白质发生改变，包括热休克蛋白。稀疏分布 VSMC 的脑血管也吸引了大量的血管周微胶质细胞/巨噬细胞，以 CD45 > CD163 > CD68 细胞的顺序聚集，超过 60%的血管壁表现出细胞间粘附分子-1（ICAM-1）免疫反应性。携带 NOTCH3 Arg133Cys 突变的功能性 VSMC 培养物显示，促炎细胞因子白细胞介素 6 和 ICAM-1 的基因表达分别增加了 16 倍和 50 倍。我们还发现了补体替代途径激活的证据。补体因子 B、C3d 和 C5-9 末端复合物的免疫定位，但不是 C1q，在大约 70%的脑血管中是明显的。在携带 Arg133Cys 突变的超过 70%的培养 VSMC 中，补体表达增加，与 N3ECD 免疫反应性无关。我们的观察结果表明，ER 应激和与小动脉 VSMC 损伤相关的其他细胞特征引发了 CADASIL 中强烈的局部炎症和免疫反应。我们的研究对免疫调节方法具有重要意义，可以对抗 CADASIL 的特征性小动脉病。
