Perivascular fibroblasts, vascular fibrosis, and their contributions to cerebral amyloid angiopathy

项目总结 脑淀粉样血管病是一种当淀粉样β蛋白(Aβ)在大脑上形成沉淀物时发生的疾病 血管。CAA经常与阿尔茨海默病(AD)并存，是 颅内出血和痴呆症。目前还没有批准的治疗CAA的方法，其分子病因学 该病的病因尚不清楚，这阻碍了有效的治疗干预措施的发展。 在此，我们建议研究脑血管周围成纤维细胞和血管纤维化信号通路。 CAA病理学的贡献者。20多年前，开创性的工作表明星形胶质细胞特异性 组织纤维化的主要调节因子转化生长因子β1(转化生长因子β1)的上调可以特异性地 在脑血管系统中诱导Aβ病理，这使人联想到CAA。然而，机械性的行动 转化生长因子β-1是如何驱动这一反应的一直没有阐明。在研究死后人脑组织中 从CAA患者中，我们发现脑血管周围成纤维细胞获得周围的肌成纤维细胞标志。 有β沉积和纤维化征象的血管--这种表型仅见于CAA，而不是AD或AD 年龄匹配的对照组。此外，这种表型在5xFAD小鼠脑室内注射后复制 人类血管来源的人类Aβ种子，产生CAA样病理。因此，我们假设 血管周围成纤维细胞激活和血管周围信号转导通路导致β CAA表型的沉积、血管纤维化和获得。在目标1中，我们将探索这一假设 在两个使用三维组织成像技术的互补小鼠模型中，单细胞RNA 测序和血流量测量。在目标2中，我们将利用一种新的人类生物工程模型 脑小动脉了解转化生长因子β-1如何通过多细胞途径塑造纤维化微环境 相声。在目标3中，同样是在小鼠模型中，我们将针对脑血管周围成纤维细胞和纤维化信号。 使用基因沉默技术和小分子治疗的途径，并确定CAA病理是否 减少了。总的来说，这些研究将揭示和描述血管周围成纤维细胞和血管 纤维化在CAA病理中起重要作用。此外，这些研究将确定潜在的临床前药物。 发展策略侧重于靶向成纤维细胞激活和信号通路，这些信号通路有助于促进 CAA纤维化微环境的研究。

Project summary Cerebral amyloid angiopathy (CAA) is a disease that occurs when amyloid beta (Aβ) forms deposits on brain blood vessels. CAA frequently co-occurs with Alzheimer’s disease (AD) and is a significant risk factor for intracranial hemorrhage and dementia. There are no approved treatments for CAA, and the molecular etiology of the disease remains unclear, which has prevented the development of effective therapeutic interventions. Here, we propose to study cerebral perivascular fibroblasts and vascular fibrosis signaling pathways as potential contributors to CAA pathology. More than 20 years ago, pioneering work showed that astrocyte-specific upregulation of transforming growth factor beta 1 (TGFβ1), a master regulator of tissue fibrosis, could specifically induce Aβ pathology in the cerebrovasculature that was reminiscent of CAA. However, the mechanistic actions of TGFβ1 that could drive such a response were never elucidated. In studying postmortem human brain tissue from CAA patients, we have found that cerebral perivascular fibroblasts acquire myofibroblast markers around vessels with Aβ deposition and fibrotic signatures—this phenotype is observed specifically in CAA but not AD or age-matched controls. Further, this phenotype is replicated in 5xFAD mice after intracerebroventricular injections of human vascular-derived human Aβ seeds, which yields CAA-like pathology. Hence, we hypothesize that activation of perivascular fibroblasts and fibrotic signaling pathways in the perivascular niche leads to Aβ deposition, vascular fibrosis, and acquisition of the CAA phenotype. In Aim 1, we will explore this hypothesis within two complementary mouse models using three-dimensional tissue imaging techniques, single-cell RNA sequencing, and blood flow measurements. In Aim 2, we will leverage a novel bioengineered model of human cerebral arterioles to understand how TGFβ1 shapes the fibrotic microenvironment through multicellular crosstalk. In Aim 3, again in mouse models, we will target cerebral perivascular fibroblasts and fibrotic signaling pathways using gene silencing techniques and small molecule treatments and determine if CAA pathology is lessened. Collectively, these studies will unveil and characterize how perivascular fibroblasts and vascular fibrosis contribute to CAA pathology. Moreover, these investigations will identify potential preclinical drug development strategies focused on targeting fibroblast activation and signaling pathways that contribute to a pro- fibrotic microenvironment in CAA.