Pediatric Stem Cell Research Institute, Edmond and Lily Sara Children's Hospital, Sheba Medical Center, Ramat-Gan, Israel.
Pediatric Research Center for Genetics, Development and Environment, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
J Am Soc Nephrol. 2021 Sep;32(9):2242-2254. doi: 10.1681/ASN.2020111546. Epub 2021 Jun 10.
Although coronavirus disease 2019 (COVID-19) causes significan t morbidity, mainly from pulmonary involvement, extrapulmonary symptoms are also major componen ts of the disease. Kidney disease, usually presenting as AKI, is particularly severe among patients with COVID-19. It is unknown, however, whether such injury results from direct kidney infection with COVID-19's causative virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), or from indirect mechanisms.
Using cell models, we sought to analyze SARS-CoV-2 interactions with kidney tubular cells and assess direct tubular injury. These models comprised primary human kidney epithelial cells (derived from nephrectomies) and grown as either proliferating monolayers or quiescent three-dimensional kidney spheroids.
We demonstrated that viral entry molecules and high baseline levels of type 1 IFN-related molecules were present in monolayers and kidney spheroids. Although both models support viral infection and replication, they did not exhibit a cytopathic effect and cell death, outcomes that were strongly present in SARS-CoV-2-infected controls (African green monkey kidney clone E6 [Vero E6] cultures). A comparison of monolayer and spheroid cultures demonstrated higher infectivity and replication of SARS-CoV-2 in actively proliferating monolayers, although the spheroid cultures exhibited high er levels of ACE2. Monolayers exhibited elevation of some tubular injury molecules-including molecules related to fibrosis (COL1A1 and STAT6) and dedifferentiation (SNAI2)-and a loss of cell identity, evident by reduction in megalin (LRP2). The three-dimensional spheroids were less prone to such injury.
SARS-CoV-2 can infect kidney cells without a cytopathic effect. AKI-induced cellular proliferation may potentially intensify infectivity and tubular damage by SARS-CoV-2, suggesting that early intervention in AKI is warranted to help minimize kidney infection.
虽然 2019 年冠状病毒病（COVID-19）会导致显著的发病率，主要是肺部受累，但肺外症状也是疾病的主要组成部分。COVID-19 患者的肾脏疾病通常表现为急性肾损伤（AKI），尤其严重。然而，尚不清楚这种损伤是由 COVID-19 的致病病毒，即严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）直接感染肾脏引起，还是由间接机制引起。
我们使用细胞模型分析 SARS-CoV-2 与肾小管细胞的相互作用，并评估直接肾小管损伤。这些模型包括源自肾切除术的原代人肾脏上皮细胞，并培养为增殖单层或静止的三维肾球体。
我们证明了病毒进入分子和高水平的 1 型干扰素相关分子存在于单层和肾球体中。尽管这两种模型都支持病毒感染和复制，但它们没有表现出细胞病变效应和细胞死亡，而这些结果在 SARS-CoV-2 感染对照（非洲绿猴肾克隆 E6[Vero E6]培养物）中非常明显。单层和球体培养物的比较表明，在活跃增殖的单层中 SARS-CoV-2 的感染性和复制性更高，尽管球体培养物表现出更高水平的 ACE2。单层表现出一些肾小管损伤分子的升高，包括与纤维化（COL1A1 和 STAT6）和去分化（SNAI2）相关的分子，以及细胞身份的丧失，表现为 megalin（LRP2）减少。三维球体则较少发生这种损伤。
SARS-CoV-2 可以感染肾脏细胞而不产生细胞病变效应。AKI 诱导的细胞增殖可能会增强 SARS-CoV-2 的感染性和肾小管损伤，这表明需要早期干预 AKI，以帮助最大限度地减少肾脏感染。
