Fig. 6

SARS-CoV-2 infection increases serum progesterone levels in COVID-19 patients. a–c Analysis of sex-related hormones in healthy individuals and SARS-CoV-2-infected patients. The measurements of testosterone (T), estradiol (E2) and progesterone (P4) are shown in (a). The age-classified data of P4 are shown in (b). The measurements of LH and FSH levels are shown in (c). *P < 0.05; **P < 0.01; ***P < 0.001; ns, not significant. d Correlation analysis between progesterone levels and severity of symptoms of COVID-19. e Effects of progesterone on replication of SARS-CoV-2 in Calu-3 cells. Calu-3 cells were treated with P4 (1 μM) for 1 h and then infected with SARS-CoV-2 (MOI = 0.01) for 48 h. Total RNAs in both cell lysate and the supernatant was collected to detect the envelope (e) and nucleocapsid (N) RNA of SARS-CoV-2 via TaqMan-qRT-PCR. f Effects of progesterone on replication of SARS-CoV-2 in mice. The K18-hACE2 transgenic mice (n = 3 in each group, 8-week-old male) were injected intraperitoneally (i.p.) with DMSO or P4 (30 μg/kg) for half an hour, and then intranasally infected with 250 PFU of SARS-CoV-2 in a total volume of 50 μl DMEM. Mice were then continued to be administered with DMSO or P4 daily until five days post-challenge. Viral genomic copy numbers in the lungs of infected mice were quantified by qPCR. g A work model for modulation of innate antiviral response by humoral progesterone