Universidade Federal do Ceará, Faculdade de Medicina, Departamento de Fisiologia e Farmacologia, Núcleo de Pesquisa e Desenvolvimento de Medicamentos, Laboratório de Neurofarmacologia, Fortaleza, CE, Brasil.
Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Departamento de Fisiologia e Biofísica, Laboratório de Imunologia e Mecânica Pulmonar, Belo Horizonte, MG, Brasil.
Mem Inst Oswaldo Cruz. 2023 Mar 31;118:e220144. doi: 10.1590/0074-02760220144. eCollection 2023.
The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants can infect common mice inducing significant pathological lung lesions and inflammatory responses. This substantially mimics coronavirus disease 19 (COVID-19) infection and pathogenesis in humans.
To characterise the effects of recombinant SARS-CoV-2 S1 receptor-binding domain (RBD) peptide in murine macrophage and microglial cells' immune activation compared with classical PAMPs in vitro.
Murine RAW 264.7 macrophages and BV2 microglial cells were exposed to increasing concentrations of the RBD peptide (0.01, 0.05, and 0.1 µg/mL), Lipopolysaccharide (LPS) and Poly(I:C) and evaluated after two and 24 h for significant markers of macrophage activation. We determined the effects of RBD peptide on cell viability, cleaved caspase 3 expressions, and nuclear morphometry analysis.
In RAW cells, RBD peptide was cytotoxic, but not for BV2 cells. RAW cells presented increased arginase activity and IL-10 production; however, BV2 cells expressed iNOS and IL-6 after RBD peptide exposure. In addition, RAW cells increased cleaved-caspase-3, apoptosis, and mitotic catastrophe after RBD peptide stimulation but not BV2 cells.
RBD peptide exposure has different effects depending on the cell line, exposure time, and concentration. This study brings new evidence about the immunogenic profile of RBD in macrophage and microglial cells, advancing the understanding of SARS-Cov2 immuno- and neuropathology.
新型严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）变体可感染普通小鼠，引起明显的肺部病变和炎症反应。这在很大程度上模拟了人类的 2019 年冠状病毒病（COVID-19）感染和发病机制。
比较 SARS-CoV-2 S1 受体结合域（RBD）肽与经典 PAMP 在体外对小鼠巨噬细胞和小神经胶质细胞免疫激活的影响。
用不同浓度的 RBD 肽（0.01、0.05 和 0.1μg/ml）、脂多糖（LPS）和 Poly（I：C）处理 RAW264.7 巨噬细胞和 BV2 小神经胶质细胞，并在 2 和 24 小时后评估巨噬细胞活化的显著标志物。我们测定了 RBD 肽对细胞活力、caspase-3 表达和核形态计量分析的影响。
在 RAW 细胞中，RBD 肽具有细胞毒性，但对 BV2 细胞没有毒性。RAW 细胞表现出精氨酸酶活性和 IL-10 产生增加；然而，BV2 细胞在暴露于 RBD 肽后表达 iNOS 和 IL-6。此外，RAW 细胞在 RBD 肽刺激后增加了 cleaved-caspase-3、细胞凋亡和有丝分裂灾难，但 BV2 细胞没有。
RBD 肽的暴露取决于细胞系、暴露时间和浓度，具有不同的影响。本研究为 RBD 在巨噬细胞和小神经胶质细胞中的免疫原性特征提供了新的证据，加深了对 SARS-CoV2 免疫和神经病理学的认识。
