Thoracic aortic aneurysm (TAA) is a life-threatening vascular disease frequently associated with underlying genetic causes. An inadequate understanding of human TAA pathogenesis highlights the need for better disease models. Here, we established a functional human TAA model in an animal host by combining human induced pluripotent stem cells (hiPSCs), bioengineered vascular grafts (BVGs), and gene editing. We generated BVGs from isogenic control hiPSC-derived vascular smooth muscle cells (SMCs) and mutant SMCs gene-edited to carry a Loeys-Dietz syndrome (LDS)–associated pathogenic variant ( TGFBR1 A230T ). We also generated hiPSC-derived BVGs using cells from a patient with LDS ( Patient A230T/+ ) and using genetically corrected cells ( Patient +/+ ). Control and experimental BVGs were then implanted into the common carotid arteries of nude rats. The TGFBR1 A230T variant led to impaired mechanical properties of BVGs, resulting in lower burst pressure and suture retention strength. BVGs carrying the variant dilated over time in vivo, resembling human TAA formation. Spatial transcriptomics profiling revealed defective expression of extracellular matrix (ECM) formation genes in Patient A230T/+ BVGs compared with Patient +/+ BVGs. Histological analysis and protein assays validated quantitative and qualitative ECM defects in Patient A230T/+ BVGs and patient tissue, including decreased collagen hydroxylation. SMC organization was also impaired in Patient A230T/+ BVGs as confirmed by vascular contraction testing. Silencing of collagen-modifying enzymes with small interfering RNAs reduced collagen proline hydroxylation in SMC-derived tissue constructs. These studies demonstrated the utility of BVGs to model human TAA formation in an animal host and highlighted the role of reduced collagen modifying enzyme activity in human TAA formation.

中文翻译：

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具有致病性 TGFBR1 变异的生物工程血管移植物模型体内动脉瘤形成并揭示潜在的胶原蛋白缺陷


胸主动脉瘤（TAA）是一种危及生命的血管疾病，通常与潜在的遗传原因有关。对人类 TAA 发病机制的了解不足凸显了对更好疾病模型的需求。在这里，我们通过结合人类诱导多能干细胞（hiPSC）、生物工程血管移植物（BVG）和基因编辑，在动物宿主中建立了功能性人类TAA模型。我们从同基因对照 hiPSC 衍生的血管平滑肌细胞 (SMC) 和经过基因编辑以携带 Loeys-Dietz 综合征 (LDS) 相关致病变异的突变 SMC 中生成了 BVG。转化生长因子BR1 A230T ）。我们还使用 LDS 患者的细胞生成了 hiPSC 衍生的 BVG（病人A230T/+ ）并使用经过基因校正的细胞（病人+/+ ）。然后将对照和实验 BVG 植入裸鼠的颈总动脉。这转化生长因子BR1 A230T变体导致 BVG 的机械性能受损，导致爆破压力和缝合线保持强度降低。携带该变体的 BVG 在体内随着时间的推移而扩张，类似于人类 TAA 的形成。空间转录组学分析揭示了细胞外基质（ECM）形成基因的表达缺陷病人A230T/+ BVG 与病人+/+ BVG。组织学分析和蛋白质测定验证了 ECM 缺陷的定量和定性病人A230T/+ BVG 和患者组织，包括胶原羟基化减少。 SMC组织也受到损害病人A230T/+通过血管收缩测试证实的 BVG。用小干扰 RNA 沉默胶原修饰酶可减少 SMC 衍生组织结构中的胶原脯氨酸羟基化。这些研究证明了 BVG 在动物宿主体内模拟人类 TAA 形成的效用，并强调了胶原蛋白修饰酶活性降低在人类 TAA 形成中的作用。