SARS-CoV-2 infection of human pluripotent stem cell-derived vascular cells reveals smooth muscle cells as key mediators of vascular pathology during infection
Nearly 20% of hospitalized patients diagnosed with severe SARS-CoV-2 infection are at risk for thromboembolic events. We developed a model of SARS-CoV-2 infection using human-induced pluripotent stem cell-derived endothelial cells, pericytes, and smooth muscle cells to recapitulate the vascular pathology associated with SARS-CoV-2 exposure. Our results demonstrate that perivascular cells, particularly smooth muscle cells (SMCs), are a specifically susceptible vascular target for SARS-CoV-2 infection. Utilizing RNA sequencing, we characterized the transcriptomic changes accompanying SARS-CoV-2 infection of SMCs, and endothelial cells (ECs). We observed that infected human SMCs shift to a pro-inflammatory state and increase the expression of key mediators of the coagulation cascade. Further, we showed human ECs exposed to the secretome of infected SMCs produce hemostatic factors that can contribute to vascular dysfunction, despite not being susceptible to direct infection. The findings here recapitulate observations from patient sera in human COVID-19 patients and provide mechanistic insight into the unique vascular implications of SARS-CoV-2 infection at a cellular level. Overall design: Human endothelial cells (ECs), pericytes (PCs), and smooth muscle cells (SMCs) were differentiated from human pluripotent stem cells(hPSCs). hPSC-derived ECs and SMCs were treated with either live SARS-CoV-2, heat-inactivated (HI) SARS-CoV-2 or mock-infected (no virus). We compared the transcriptional changes induced by each of these conditions in both ECs and SMCs. We also compared the transcriptional changes induced by the treatment of ECs with media from SMCs that were infected with SARS-CoV-2 or HI SARS-CoV-2. For the media transfer experiments, ECs were exposed to media from SMCs that had been exposed to live or HI SARS-CoV-2, and then RNA was isolated from the ECs 48 hours after exposure.