SARS‐CoV‐2 spike protein alleviates atherosclerosis by suppressing macrophage lipid uptake through regulating R‐loop formation on MSR1 mRNA

Abstract

Dear Editor, Atherosclerosis, as the leading cause of coronary artery disease is one of themajor contributors of death globally.1,2 SARS-CoV-2 causing the novel COVID-19 respiratory infectious disease is affecting socioeconomic and healthcare systems globally.3 Whether SARS-CoV-2 infection influences on atherosclerosis development or any virus component can affect or even ameliorate this progress is not clear. We reanalyzed scRNA-seq data of COVID-19 patient blood samples and found SARS-CoV-2 infectionmay affect CD36 andMSR1 expressions whichmediate lipid uptake of macrophages contributing to atherosclerosis progression (Supporting information Figure S1). SARS-CoV-2 mhain structural proteins, including S (spike), N (nucleocapsid), M (membrane), and E (envelope), were synthesized and transfected (Figure 1A). Combining Q-PCR and western blot results, we found viral S protein reducesMSR1 expression in macrophages (Figure 1B and C). Lipid uptake analysis shows recombinant S pretreatment or S pseudotype virus infection suppresses macrophage lipid uptake (Figure 1D-F). And, S incubation or pseudotype virus infection also decreased MSR1 expression in macrophages (Figure 1G). But, MSR1 knockout canceled this inhibitory effect of S or S pseudotype virus on macrophage lipid uptake (Figure 1H and J). Using dual luciferase reporter system, we found S had no significant effect on MSR1 transcription (Figure 1K). RIP assay shown S does not bind to MSR1 mRNA (Figure 1L). Through performing co-IP and subsequent mass-spectra analysis, proteins related to metabolism of RNA and mRNA splicing were identified to interact with S (Figure 1M and N). DDX5, involved in multiple steps of RNAmetabolism interacts with S protein in macrophages (Figure 1O). In addition, S did not affect DDX5 mRNA or protein expression (Figure 1P and Q). DDX5 overexpression evidently cancels the inhibitory effect of S on MSR1 protein expression (Figure 1R).