Neuropilin 1: A Novel Entry Factor for SARS-CoV-2 Infection and a Potential Therapeutic Target

The novel coronavirus disease 2019 (COVID-19) pandemic is severely challenging the healthcare systems and economies of the world, which urgently demand vaccine and therapy development to combat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Hence, advancing our understanding of the comprehensive entry mechanisms of SARS-CoV-2, especially the host factors that facilitate viral infection, is crucial for the discovery of effective vaccines and antiviral drugs. SARS-CoV-2 has previously been documented to reach cells by binding with ACE2 and CD147 receptors in host cells that interact with the spike (S) protein of SARS-CoV-2. A novel entry factor, called neuropilin 1(NRP1), has recently been discovered as a co-receptor facilitating the entry of SARS-CoV-2. NRP1 is a single-pass transmembrane glycoprotein widely distributed throughout the tissues of the body and acts as a multifunctional co-receptor to bind with different ligand proteins and play diverse physiological roles as well as pathological and therapeutic roles in different clinical conditions/diseases, including COVID-19. The current review, therefore, briefly provides the overview of SARS-CoV-2 entry mechanisms, the structure of NRP1, and their roles in health and various diseases, as well as extensively discusses the current understanding of the potential implication of NRP1 in SARS-CoV-2 entry and COVID-19 treatment.