Figure 1

The characteristics of the IEC#17. The IEC#17 monolayers were cultured in a differentiation medium from day 2. (A, B) IEC#17 cells were collected at the indicated time points. Relative mRNA expression of the indicated genes in IEC#17 during the course of differentiation (days 2, 4, and 6) were determined by qRT-PCR and normalized against the expression of GAPDH. Each result was normalized by the expression level at two-day after differentiation. Each value is representative of at least three independent experiments and is shown as the mean ± SD from three wells of cells of each culture group. The significant differences were determined using one-way ANOVA. (A) The transcription of the major intestinal markers was measured using qRT-PCR. We included LYZ, SI, CHGA, VIL1, LGR5 and MUC2 which is the marker of Paneth cell, enterocyte, enteroendocrine cell, IEC, stem cell and goblet cell, respectively. (B) The transcription of the major host factors important for SARS-CoV-2 infection was measured using qRT-PCR. We included ACE2, FURIN, CTSL, TMPRSS2 and TMPRSS4. (C) Schematic diagrams of the immunostaining analysis. The black arrow indicates the direction from which the photograph was taken. (D) The protein expressions of ZO-1, ACE2, and TMPRSS2 in IEC#17 monolayers were visualized by immunofluorescence. IEC#17 monolayers were fixed and stained at the indicated time points. The scale bar indicates 50 µm. (E) The protein expressions of ACE2 in IEC#17 monolayers with polarity were visualized by immunofluorescence. The photo was taken from vertical angle at six-day after differentiation. The white broken bar indicates Transwell membranes. *0.01 < P < 0.05; **0.005 < P < 0.01; ***P < 0.005.