Abstract
Coronavirus disease 19 (COVID-19) is a respiratory illness caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). COVID-19 pathogenesis causes vascular-mediated neurological disorders via elusive mechanisms. SARS-CoV-2 infects host cells via the binding of viral Spike (S) protein to transmembrane receptor, angiotensin-converting enzyme 2 (ACE2). Although brain pericytes were recently shown to abundantly express ACE2 at the neurovascular interface, their response to SARS-CoV-2 S protein is still to be elucidated. Using cell-based assays, we found that ACE2 expression in human brain vascular pericytes was increased upon S protein exposure. Pericytes exposed to S protein underwent profound phenotypic changes associated with an elongated and contracted morphology accompanied with an enhanced expression of contractile and myofibrogenic proteins, such as α-smooth muscle actin (α-SMA), fibronectin, collagen I, and neurogenic locus notch homolog protein-3 (NOTCH3). On the functional level, S protein exposure promoted the acquisition of calcium (Ca 2+) signature of contractile ensheathing pericytes characterized by highly regular oscillatory Ca 2+ fluctuations. Furthermore, S protein induced lipid peroxidation, oxidative and nitrosative stress in pericytes as well as triggered an immune reaction translated by activation of nuclear factor-kappa-B (NF-κB) signaling pathway, which was potentiated by hypoxia, a condition associated with vascular comorbidities that exacerbate COVID-19 pathogenesis. S protein exposure combined to hypoxia enhanced the production of pro-inflammatory cytokines involved in immune cell activation and trafficking, namely macrophage migration inhibitory factor (MIF). Using transgenic mice expressing the human ACE2 that recognizes S protein, we observed that the intranasal infection with SARS-CoV-2 rapidly induced hypoxic/ischemic-like pericyte reactivity in the brain of transgenic mice, accompanied with an increased vascular expression of ACE2. Moreover, we found that SARS-CoV-2 S protein accumulated in the intranasal cavity reached the brain of mice in which the nasal mucosa is deregulated. Collectively, these findings suggest that SARS-CoV-2 S protein impairs the vascular and immune regulatory functions of brain pericytes, which may account for vascular-mediated brain damage. Our study provides a better understanding for the mechanisms underlying cerebrovascular disorders in COVID-19, paving the way to develop new therapeutic interventions.
Keywords: COVID-19; Cerebrovascular disorders; Inflammation; Myofibrogenic transition; Neurovascular interface; Pericytes; SARS-CoV-2 S protein.
【저자키워드】 COVID-19, Inflammation, pericytes, cerebrovascular disorders, Myofibrogenic transition, Neurovascular interface, SARS-CoV-2 S protein., 【초록키워드】 coronavirus disease, SARS-CoV-2, Macrophage, ACE2, Cytokines, Stress, hypoxia, S protein, spike, Respiratory illness, Comorbidity, Proteins, severe acute respiratory syndrome Coronavirus, angiotensin-converting enzyme 2, immune, lipid peroxidation, Brain, Fibronectin, human ACE2, Regulatory, Severe acute respiratory syndrome, Protein, Migration, COVID-19 pathogenesis, mice, pericyte, pro-inflammatory cytokines, morphology, mechanisms, pericytes, collagen, signaling pathway, receptor, coronavirus disease 19, Neurological disorders, ACE2 expression, expression, change, nasal mucosa, calcium, mechanism, intranasal, function, binding, SARS-CoV-2 S protein, NF-κB, Angiotensin-converting enzyme, Coronavirus-2, Human brain, Neurological disorder, angiotensin, Immune cell, brain damage, cerebrovascular, host cells, host cell, Neurovascular, acute respiratory syndrome, Activation, Vascular, locus, acute respiratory syndrome coronavirus, enzyme, acute respiratory syndrome coronavirus-2, transgenic mice, therapeutic interventions, transmembrane, pro-inflammatory cytokine, viral spike, disorder, phenotypic, Express, fluctuations, acquisition, homolog, Actin, immune reaction, nuclear, inhibitory, infect, NOTCH3, oxidative, shown, develop, caused, involved, assays, characterized, functional, provide, recognize, cause, triggered, reached, reactivity, expressing, translated, impair, promoted, accumulated, exacerbate, accompanied, deregulated, contractile, infection with SARS-CoV-2, MIF, was increased, 【제목키워드】 SARS-CoV-2, spike, Protein, immune function, pericyte, Vascular,