Removal of Soluble ACE2 in VeroE6 Cells by 17β-Estradiol Reduces SARS-CoV-2 Infectivity

Abstract

Women are less susceptible than men to coronavirus disease 2019 , which might be due to the female steroid hormone 17β-estradiol. We hypothesized that 17β-estradiol removes the soluble portion of angiotensin-converting enzyme 2 (sACE2) to which SARS-CoV-2 binds in host cells and that sACE2 then binds to the virus, thereby reducing the infectivity. In the present study, VeroE6/TMPRSS2 cells were infected with pseudo SARS-CoV-2 viruses and used as our model system. This infectivity was reduced by the application of 17β-estradiol. After applying 17β-estradiol to the VeroE6/TMPRSS2 cells, we used a sandwich enzyme-linked immunosorbent assay to measure the sACE2 concentration in the culture medium. Our findings revealed that 17β-estradiol removes sACE2 from VeroE6/TMPRSS2 cells. Furthermore, the pseudo SARS-CoV-2 viruses were incubated in culture medium with ACE2 collected from 17β-estradiol-treated VeroE6/TMPRSS2 cells, and the viruses were measured with an ultrasensitive ELISA using anti-spike protein antibodies. The amount of spike proteins decreased according to the concentration of 17β-estradiol applied. These results clearly demonstrated that the soluble portion of ACE2, which was removed from 17β-estradiol-treated VeroE6/TMPRSS2 cells, bound to the spike proteins of SARS-CoV-2, thereby reducing COVID-19 infectivity.

Quantification of HPV16 E7 Oncoproteins in Urine Specimens from Women with Cervical Intraepithelial Neoplasia

“…The resultant precipitates were resolved with 2 mL of ThinPrep solution (Hologic, Marlborough, MA, USA) and stored at –80 °C. Our ultrasensitive ELISA with thio-NAD cycling was based on a sandwich ELISA and developed by Watabe and Ito [ 15 ]; the details are described elsewhere [ 25 , 26 ]. Briefly, 2 μg/mL of primary antibody (NM2) against HPV16 E7 oncoprotein, provided by an author (M.M.…”

“…Specimens were processed for measurements using the ultrasensitive ELISA with thio-NAD cycling as follows: 45 mL of urine was collected from each patient and centrifuged at 3000 rpm for 5 min. The resultant precipitates were resolved with 2 mL of ThinPrep solution (Hologic, Marlborough, MA, USA) and stored at -80 • C. Our ultrasensitive ELISA with thio-NAD cycling was based on a sandwich ELISA and developed by Watabe and Ito [15]; the details are described elsewhere [25,26]. Briefly, 2 µg/mL of primary antibody (NM2) against HPV16 E7 oncoprotein, provided by an author (M.M.…”