As a consequence of SARS-CoV-2 infection various neurocognitive and neuropsychiatric symptoms can appear, which may persist for several months post infection. However, cell type-specific routes of brain infection and underlying mechanisms resulting in neuroglial dysfunction are not well understood. Here, we investigated the susceptibility of cells constituting the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB) of the choroid plexus (ChP) to SARS-CoV-2 infection using human induced pluripotent stem cell (hiPSC)-derived cellular models and a ChP papilloma-derived epithelial cell line as well as ChP tissue from COVID-19 patients, respectively. We noted a differential infectibility of hiPSC-derived brain microvascular endothelial cells (BMECs) depending on the differentiation method. Extended endothelial culture method (EECM)-BMECs characterized by a complete set of endothelial markers, good barrier properties and a mature immune phenotype were refractory to SARS-CoV-2 infection and did not exhibit an activated phenotype after prolonged SARS-CoV-2 inoculation. In contrast, defined medium method (DMM)-BMECs, characterized by a mixed endothelial and epithelial phenotype and excellent barrier properties were productively infected by SARS-CoV-2 in an ACE2-dependent manner. hiPSC-derived brain pericyte-like cells (BPLCs) lacking ACE2 expression were not susceptible to SARS-CoV-2 infection. Furthermore, the human choroid plexus papilloma-derived epithelial cell line HIBCPP, modeling the BCSFB was productively infected by SARS-CoV-2 preferentially from the basolateral side, facing the blood compartment. Assessment of ChP tissue from COVID-19 patients by RNA in situ hybridization revealed SARS-CoV-2 transcripts in ChP epithelial and ChP stromal cells. Our study shows that the BCSFB of the ChP rather than the BBB is susceptible to direct SARS-CoV-2 infection. Thus, neuropsychiatric symptoms because of COVID-19 may rather be associated with dysfunction of the BCSFB than the BBB. Future studies should consider a role of the ChP in underlying neuropsychiatric symptoms following SARS-CoV-2 infection.

中文翻译：

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SARS-CoV-2 感染血脑脊液屏障的上皮细胞，而不是血脑屏障的内皮细胞或周细胞

SARS-CoV-2 感染可能会出现各种神经认知和神经精神症状，这些症状可能会在感染后持续数月。然而，大脑感染的细胞类型特异性途径和导致神经胶质功能障碍的潜在机制尚不清楚。在这里，我们使用人诱导多能干细胞（hiPSC）研究了构成脉络丛（ChP）血脑屏障（BBB）和血脑脊液屏障（BCSFB）的细胞对SARS-CoV-2感染的敏感性分别是衍生的细胞模型和 ChP 乳头状瘤衍生的上皮细胞系以及来自 COVID-19 患者的 ChP 组织。我们注意到 hiPSC 来源的脑微血管内皮细胞 (BMEC) 的感染性存在差异，具体取决于分化方法。扩展内皮培养法（EECM）-BMEC具有完整的内皮标记、良好的屏障特性和成熟的免疫表型，对SARS-CoV-2感染具有抵抗力，并且在长期接种SARS-CoV-2后没有表现出激活的表型。相比之下，以混合内皮和上皮表型以及优异的屏障特性为特征的限定培养基法 (DMM)-BMEC，可以以 ACE2 依赖性方式有效地被 SARS-CoV-2 感染。缺乏 ACE2 表达的 hiPSC 来源的脑周细胞样细胞 (BPLC) 不易受到 SARS-CoV-2 感染。此外，模拟 BCSFB 的人脉络丛乳头状瘤来源的上皮细胞系 HIBCPP 优先从面向血液室的基底外侧有效地被 SARS-CoV-2 感染。通过 RNA 原位杂交对 COVID-19 患者的 ChP 组织进行评估，发现 ChP 上皮细胞和 ChP 基质细胞中存在 SARS-CoV-2 转录本。我们的研究表明，ChP 的 BCSFB 而不是 BBB 更容易直接感染 SARS-CoV-2。因此，COVID-19 引起的神经精神症状可能与 BCSFB 功能障碍有关，而不是与 BBB 功能障碍有关。未来的研究应考虑 ChP 在 SARS-CoV-2 感染后潜在神经精神症状中的作用。