Neural epidermal growth factor-like 1 protein variant increases survival and modulates the inflammatory and immune responses in human ACE-2 transgenic mice infected with SARS-CoV-2

Coronavirus disease 2019 (COVID-19) is a viral illness caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and is a worsening global pandemic. COVID-19 has caused at least 1.7 million deaths worldwide and over 300,000 in the United States. Recently, two promising vaccines are being administered in several countries. However, there remains an urgent need for a therapeutic treatment for COVID-19 patients with severe respiratory damage that can lead to intensive care, prolonged hospitalization, or mortality. Moreover, an increasing population of patients manifest lingering disabling symptoms (called Long Haulers). Here, we tested the efficacy of a recombinant neural epidermal growth factor like 1 protein variant (NELL1-NV1) in a COVID-19 mouse model, transgenic mice expressing the human angiotensin I-converting enzyme 2 (ACE2) receptor (tg-mice hACE2) infected with SARS-CoV-2. The administration of NELL1-NV1 to SARS-CoV-2-infected tg-mice hACE2 significantly improved clinical health score and increased survival. Analyses of bronchoalveolar (BAL) fluid demonstrated decreased levels of several cytokines and chemokines (IFN-{gamma}, IL-10, IL-12 p70, CXCL-10/IP-10, MIG and Rantes), in NV1-treated treated mice compared to controls. Cytokines including IL-1, IL-9, IL-6, LIX/CXCL5, KC/CXCL1, MIP-2/CXCL2, MIP-1/CCL3, and G-CSF, critical to immune responses such as neutrophil recruitment, viral clearance and vascularization, were increased compared to controls. Our data suggest the potential of NELL1-NV1-based therapy to mitigate the cytokine storm, modulate the abnormal immune response and repair respiratory tissue damage in COVID-19 patients.