Massachusetts General Hospital, Center for Regenerative Medicine, Boston, MA, USA; Harvard Medical School, Boston, MA, USA.
Massachusetts General Hospital, Department of Surgery, Boston, MA, USA; Massachusetts General Hospital, Division of Cardiovascular Surgery, Boston, MA, USA.
Biomaterials. 2022 Jun;285:121509. doi: 10.1016/j.biomaterials.2022.121509. Epub 2022 Apr 11.
The catastrophic global effects of the SARS-CoV-2 pandemic highlight the need to develop novel therapeutics strategies to prevent and treat viral infections of the respiratory tract. To enable this work, we need scalable, affordable, and physiologically relevant models of the human lung, the primary organ involved in the pathogenesis of COVID-19. To date, most COVID-19 in vitro models rely on platforms such as cell lines and organoids. While 2D and 3D models have provided important insights, human distal lung models that can model epithelial viral uptake have yet to be established. We hypothesized that by leveraging techniques of whole organ engineering and directed differentiation of induced pluripotent stem cells (iPSC) we could model human distal lung epithelium, examine viral infection at the tissue level in real time, and establish a platform for COVID-19 related research ex vivo. In the present study, we used type 2 alveolar epithelial cells (AT2) derived from human iPSCs to repopulate whole rat lung acellular scaffolds and maintained them in extended biomimetic organ culture for 30 days to induce the maturation of distal lung epithelium. We observed emergence of a mixed type 1 and type 2 alveolar epithelial phenotype during tissue formation. When exposing our system to a pseudotyped lentivirus containing the spike of wildtype SARS-CoV-2 and the more virulent D614G, we observed progression of the infection in real time. We then found that the protease inhibitor Camostat Mesyalte significantly reduced viral transfection in distal lung epithelium. In summary, our data show that a mature human distal lung epithelium can serve as a novel moderate throughput research platform to examine viral infection and to evaluate novel therapeutics ex vivo.
SARS-CoV-2 大流行对全球造成的灾难性影响突显了开发新型治疗策略以预防和治疗呼吸道病毒感染的必要性。为了实现这一目标，我们需要可扩展、负担得起且与生理相关的人类肺部模型，这是 COVID-19 发病机制的主要器官。迄今为止，大多数 COVID-19 体外模型依赖于细胞系和类器官等平台。虽然 2D 和 3D 模型提供了重要的见解，但能够模拟上皮细胞病毒摄取的人类远端肺模型尚未建立。我们假设，通过利用整个器官工程和诱导多能干细胞 (iPSC) 定向分化的技术，我们可以模拟人类远端肺上皮细胞，实时检查组织水平的病毒感染，并建立一个用于 COVID-19 相关研究的离体平台。在本研究中，我们使用源自人类 iPSC 的 2 型肺泡上皮细胞 (AT2) 来重新填充整个大鼠肺去细胞支架，并在扩展的仿生器官培养中维持 30 天，以诱导远端肺上皮细胞的成熟。我们观察到在组织形成过程中出现了 1 型和 2 型肺泡上皮细胞的混合表型。当我们将我们的系统暴露于含有野生型 SARS-CoV-2 刺突和更具毒性的 D614G 的假型慢病毒时，我们实时观察到感染的进展。然后我们发现蛋白酶抑制剂 Camostat Mesyalte 显著减少了远端肺上皮细胞中的病毒转染。总之，我们的数据表明，成熟的人类远端肺上皮细胞可以作为一种新的中等通量研究平台，用于体外研究病毒感染和评估新型治疗方法。
