Abstract
Rationale: Macrophages are the frontline immune cells in response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Angiotensin-converting enzyme 2 (ACE2) serves as the binding receptor to SARS-CoV-2 Spike glycoprotein for fusion and internalization into the human host cells. However, the mechanisms underlying SARS-CoV-2-elicited macrophage inflammatory responses remain elusive. Neutralizing SARS-CoV-2 by human ACE2 (hACE2) decoys has been proposed as a therapeutic approach to ameliorate SARS-CoV-2-stimulated inflammation. This study aims to investigate whether an engineered decoy receptor can abrogate SARS-CoV-2-induced macrophage inflammation. Methods: hACE2 was biotinylated to the surface of nano-liposomes (d = 100 nm) to generate Liposome-human ACE2 complex (Lipo-hACE2). Lentivirus expressing Spike protein (D614G) was also created as a pseudo-SARS-CoV-2 (Lenti-Spike). Liposome-hACE2 was used as a decoy receptor or competitive inhibitor to inhibit SARS-CoV-2 or Lenti-Spike-induced macrophage inflammation in vitro and in vivo . Results: Both SARS-CoV-2 and Lenti-Spike stimulated strong inflammatory responses by inducing the expression of key cytokine and chemokines, including IL-1β, IL-6, TNFα, CCL-2, and CXCL-10, in murine and human macrophages in vitro , whereas Lipo-hACE2 decoy abolished these effects in macrophages. Furthermore, intravenous injection of Lenti-Spike led to increased macrophage and tissue inflammation in wild type mice, which was also abolished by Lipo-hACE2 treatment. Mechanistically, Spike protein stimulated macrophage inflammation by activating canonical NF-κB signaling. RNA sequencing analysis revealed that Lenti-Spike induced over 2,000 differentially expressed genes (DEGs) in murine macrophages, but deficiency of IκB kinase β (IKKβ), a key regulator for NF-κB activation, abrogated Lenti-Spike-elicited macrophage inflammatory responses. Conclusions: We demonstrated that the engineered Lipo-hACE2 acts as a molecular decoy to neutralize SARS-CoV-2 or Spike protein-induced inflammation in both murine and human macrophages, and activation of the canonical IKKβ/NF-κB signaling is essential for SARS-CoV-2-elicited macrophage inflammatory responses.
Keywords: IKKβ/NF-κB signaling; Liposome-Human ACE2; SARS-CoV-2; Spike Protein; myeloid-specific IKKβ knockout.
【저자키워드】 SARS-CoV-2, Spike protein, IKKβ/NF-κB signaling, Liposome-Human ACE2, myeloid-specific IKKβ knockout., 【초록키워드】 Treatment, Inflammation, Macrophage, ACE2, coronavirus, macrophages, Inflammatory responses, spike, IL-6, spike glycoprotein, Infection, cytokine, chemokines, in vitro, severe acute respiratory syndrome Coronavirus, angiotensin-converting enzyme 2, Spike protein, hACE2, human ACE2, Protein, mice, SARS-CoV-2 spike glycoprotein, lentivirus, RNA sequencing, D614G, immune cells, glycoprotein, receptor, molecular, human macrophage, in vivo, inhibitor, fusion, expression, wild type, mechanism, differentially expressed gene, binding, NF-κB, Angiotensin-converting enzyme, IL-1β, Signaling, Inflammatory response, Liposome, Therapeutic approach, Analysis, angiotensin, Immune cell, deficiency, acute respiratory syndrome, Activation, Intravenous injection, acute respiratory syndrome coronavirus, acute respiratory syndrome coronavirus 2, enzyme, complex, rationale, NF-κB activation, TNFα, internalization, DEGs, CCL-2, human macrophages, human host cells, CXCL-10, NF-κB signaling, murine, Effect, competitive inhibitor, neutralize, tissue inflammation, IKKβ, stimulated, was used, generate, demonstrated, abrogate, expressing, abrogated, activating, canonical, biotinylated, inhibit SARS-CoV-2, IκB, 【제목키워드】 Inflammation, ACE2, spike, human macrophage, neutralize,