Structural insights into decreased affinity of SARS-CoV-2 to ACE2 by steroids

Abstract The novel coronavirus disease (COVID-19) presently poses significant concerns around the world. Latest reports show that the degree of disease and mortality of COVID-19 infected patients may vary from gender to gender with a very high risk of death for seniors. Clearly, different levels of sex steroid hormones are found in both men and women. It was hypothesized that sex steroid hormones estradiol (E2), progesterone (P4), and testosterone (T) may change the interaction of coronavirus spike protein with angiotensin converting enzyme-2 (ACE2, which is the major SARS-CoV-2 cell entry receptor.) in the presence or absence of dexamethasone (DEX, the potential anti-inflammatory agents). Data showed that E2 was more strongly to interact with the main protease of the coronavirus, while T had the lowest affinity for coronavirus spike protein than E2 and P4. The binding energy of the spike protein to ACE2 was increased in the presence of five molecules of each steroid; the greatest increase was observed by DEX and E2. The binding free energy of the spike protein to ACE2 was the highest in the presence of both E2 and DEX molecules. Together, the interaction between spike protein and ACE2 can be disrupted by female sex steroid hormone E2 and to a greater extent by E2 and anti-inflammatory DEX, in part explaining the lower incidence of COVID-19 infection in women than men. The potential use of E2 and DEX to reduce coronavirus attachment to ACE2 in the early phase of the coronavirus invasion needs to be clinically investigated.