Department of Medicine, Queen's University, Kingston, ON, Canada; Queen's Cardiopulmonary Unit (QCPU), Queen's University, Kingston, ON, Canada.
Department of Medicine, Queen's University, Kingston, ON, Canada.
Redox Biol. 2022 Dec;58:102508. doi: 10.1016/j.redox.2022.102508. Epub 2022 Oct 13.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19 pneumonia. We hypothesize that SARS-CoV-2 causes alveolar injury and hypoxemia by damaging mitochondria in airway epithelial cells (AEC) and pulmonary artery smooth muscle cells (PASMC), triggering apoptosis and bioenergetic impairment, and impairing hypoxic pulmonary vasoconstriction (HPV), respectively.
We examined the effects of: A) human betacoronaviruses, SARS-CoV-2 and HCoV-OC43, and individual SARS-CoV-2 proteins on apoptosis, mitochondrial fission, and bioenergetics in AEC; and B) SARS-CoV-2 proteins and mouse hepatitis virus (MHV-1) infection on HPV.
We used transcriptomic data to identify temporal changes in mitochondrial-relevant gene ontology (GO) pathways post-SARS-CoV-2 infection. We also transduced AECs with SARS-CoV-2 proteins (M, Nsp7 or Nsp9) and determined effects on mitochondrial permeability transition pore (mPTP) activity, relative membrane potential, apoptosis, mitochondrial fission, and oxygen consumption rates (OCR). In human PASMC, we assessed the effects of SARS-CoV-2 proteins on hypoxic increases in cytosolic calcium, an HPV proxy. In MHV-1 pneumonia, we assessed HPV via cardiac catheterization and apoptosis using the TUNEL assay.
SARS-CoV-2 regulated mitochondrial apoptosis, mitochondrial membrane permeabilization and electron transport chain (ETC) GO pathways within 2 hours of infection. SARS-CoV-2 downregulated ETC Complex I and ATP synthase genes, and upregulated apoptosis-inducing genes. SARS-CoV-2 and HCoV-OC43 upregulated and activated dynamin-related protein 1 (Drp1) and increased mitochondrial fission. SARS-CoV-2 and transduced SARS-CoV-2 proteins increased apoptosis inducing factor (AIF) expression and activated caspase 7, resulting in apoptosis. Coronaviruses also reduced OCR, decreased ETC Complex I activity and lowered ATP levels in AEC. M protein transduction also increased mPTP opening. In human PASMC, M and Nsp9 proteins inhibited HPV. In MHV-1 pneumonia, infected AEC displayed apoptosis and HPV was suppressed. BAY K8644, a calcium channel agonist, increased HPV and improved SpO.
Coronaviruses, including SARS-CoV-2, cause AEC apoptosis, mitochondrial fission, and bioenergetic impairment. SARS-CoV-2 also suppresses HPV by targeting mitochondria. This mitochondriopathy is replicated by transduction with SARS-CoV-2 proteins, indicating a mechanistic role for viral-host mitochondrial protein interactions. Mitochondriopathy is a conserved feature of coronaviral pneumonia that may exacerbate hypoxemia and constitutes a therapeutic target.
严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）引起 COVID-19 肺炎。我们假设，SARS-CoV-2 通过损伤气道上皮细胞（AEC）和肺动脉平滑肌细胞（PASMC）中的线粒体导致肺泡损伤和低氧血症，分别触发细胞凋亡和生物能量障碍，并损害低氧性肺血管收缩（HPV）。
我们研究了以下因素的影响：A）人β冠状病毒、SARS-CoV-2 和 HCoV-OC43，以及 SARS-CoV-2 的单个蛋白对 AEC 中的细胞凋亡、线粒体裂变和生物能量的影响；B）SARS-CoV-2 蛋白和鼠肝炎病毒（MHV-1）感染对 HPV 的影响。
我们使用转录组数据来确定 SARS-CoV-2 感染后与线粒体相关的基因本体（GO）途径的时间变化。我们还通过转导 SARS-CoV-2 蛋白（M、Nsp7 或 Nsp9）来确定其对线粒体通透性转换孔（mPTP）活性、相对膜电位、细胞凋亡、线粒体裂变和耗氧率（OCR）的影响。在人 PASMC 中，我们评估了 SARS-CoV-2 蛋白对缺氧时胞质钙增加的影响，这是 HPV 的一个替代指标。在 MHV-1 肺炎中，我们通过心导管术和 TUNEL 检测评估了 HPV 和细胞凋亡。
SARS-CoV-2 在感染后 2 小时内调节了与线粒体凋亡、线粒体膜通透性和电子传递链（ETC）GO 途径相关的基因。SARS-CoV-2 下调了 ETC 复合物 I 和 ATP 合酶基因，并上调了诱导细胞凋亡的基因。SARS-CoV-2 和 HCoV-OC43 上调并激活了与分裂相关的蛋白 1（Drp1）并增加了线粒体裂变。SARS-CoV-2 和转导的 SARS-CoV-2 蛋白增加了凋亡诱导因子（AIF）的表达并激活了半胱天冬酶 7，导致细胞凋亡。冠状病毒还降低了 AEC 中的耗氧率、ETC 复合物 I 活性和 ATP 水平。M 蛋白转导也增加了 mPTP 的开放。在人 PASMC 中，M 和 Nsp9 蛋白抑制了 HPV。在 MHV-1 肺炎中，感染的 AEC 显示出细胞凋亡，HPV 受到抑制。钙通道激动剂 BAY K8644 增加了 HPV 并提高了 SpO。
冠状病毒，包括 SARS-CoV-2，导致 AEC 细胞凋亡、线粒体裂变和生物能量障碍。SARS-CoV-2 还通过靶向线粒体来抑制 HPV。这种线粒体病可以通过转导 SARS-CoV-2 蛋白来复制，表明病毒-宿主线粒体蛋白相互作用具有机制作用。线粒体病是冠状病毒肺炎的一个保守特征，可能会加重低氧血症，并构成一个治疗靶点。
