Aab Cardiovascular Research Institute and Department of Medicine, University of Rochester School of Medicine and Dentistry, NY (S.W., J.R., Y.R., T.N., R.J.W., A.M., J.P.).
Department of Cardiology, Pan-Vascular Research Institute, Shanghai Tenth People's Hospital, Tongji University School of Medicine, China (G.Z., D.J., X.L., H.L., Y.L., Y.X.).
Hypertension. 2022 Jan;79(1):79-92. doi: 10.1161/HYPERTENSIONAHA.120.16065. Epub 2021 Nov 5.
Clinical trials of Dll4 (Delta-like 4) neutralizing antibodies (Dll4nAbs) in cancer patients are ongoing. Surprisingly, pulmonary hypertension (PH) occurs in 14% to 18% of patients treated with Dll4nAbs, but the mechanisms have not been studied. Here, PH progression was measured in mice treated with Dll4nAbs. We detected Notch signaling in lung tissues and analyzed pulmonary vascular permeability and inflammation. Notch target gene array was performed on adult human pulmonary microvascular endothelial cells (ECs) after inhibiting Notch cleavage. Similar mechanisms were studied in PH mouse models and pulmonary arterial hypertension patients. The rescue effects of constitutively activated Notch1 in vivo were also measured. We observed that Dll4nAbs induced PH in mice as indicated by significantly increased right ventricular systolic pressure, as well as pulmonary vascular and right ventricular remodeling. Mechanistically, Dll4nAbs inhibited Notch1 cleavage and subsequently impaired lung endothelial barrier function and increased immune cell infiltration in vessel walls. In vitro, Notch targeted genes' expression related to cell growth and inflammation was decreased in human pulmonary microvascular ECs after the Notch1 inactivation. In lungs of PH mouse models and pulmonary arterial hypertension patients, Notch1 cleavage was inhibited. Consistently, EC cell-cell junction was leaky, and immune cell infiltration increased in PH mouse models. Overexpression activated Notch1-attenuated progression of PH in mice. In conclusion, Dll4nAbs led to PH development in mice by impaired EC barrier function and increased immune cell infiltration through inhibition of Notch1 cleavage in lung ECs. Reduced Notch1 cleavage in lung ECs could be an underlying mechanism of PH pathogenesis.
在癌症患者中进行的 Dll4（Delta-like 4）中和抗体（Dll4nAbs）的临床试验正在进行中。令人惊讶的是，接受 Dll4nAbs 治疗的患者中有 14%至 18%发生肺动脉高压（PH），但其机制尚未研究。在此，我们在接受 Dll4nAbs 治疗的小鼠中测量了 PH 的进展。我们检测了肺组织中的 Notch 信号，并分析了肺血管通透性和炎症。在抑制 Notch 切割后，对成人肺微血管内皮细胞（EC）进行了 Notch 靶基因阵列分析。在 PH 小鼠模型和肺动脉高压患者中研究了类似的机制。还测量了体内组成性激活 Notch1 的挽救作用。我们观察到，Dll4nAbs 诱导小鼠发生 PH，表现为右心室收缩压显著升高，以及肺血管和右心室重构。从机制上讲，Dll4nAbs 抑制 Notch1 切割，随后损害肺内皮屏障功能并增加血管壁中免疫细胞的浸润。在体外， Notch1 失活后，人肺微血管 EC 中与细胞生长和炎症相关的 Notch 靶向基因的表达减少。在 PH 小鼠模型和肺动脉高压患者的肺部， Notch1 切割受到抑制。一致地，EC 细胞-细胞连接处渗漏，PH 小鼠模型中免疫细胞浸润增加。过表达激活的 Notch1 可减轻小鼠 PH 的进展。总之，Dll4nAbs 通过抑制肺 EC 中的 Notch1 切割，导致肺 EC 屏障功能受损和免疫细胞浸润增加，从而导致小鼠发生 PH。肺 EC 中 Notch1 切割减少可能是 PH 发病机制的潜在机制。
