Fig. 1: ESR1 signaling in HSCs designates resistance to liver fibrosis.

a mRNA levels of the indicated receptors for sex hormones in human HSCs (male or female patients; information in Supplementary Table S1) and mouse HSCs (male or female mice; n = 2 for each sex) were profiled by RNA-seq. b, c Paraffin sections of the liver tissue samples of male or female patients (information in Supplementary Table S1) were examined by the immunofluorescence co-staining of α-SMA with ESR1 (b) or ESR2 (c). White arrowheads exemplify the ESR1-positive nuclei of α-SMA-positive HSCs. d, e Lrat^Cre;RCL-ChR2(H134R)/EYFP^+/– male or female mice were fed with the NCD or MCD diet to induce liver fibrosis. Cryosections of the liver tissues were examined by the immunofluorescence co-staining of EYFP with ESR1 (d) or ESR2 (e). White arrowheads exemplify the ESR1-positive nuclei of EYFP-positive HSCs. f–l Lrat^Cre;Esr1^fl/fl or control Esr1^fl/fl female littermates were fed with the NCD or MCD diet to induce liver fibrosis. Paraffin sections of the liver tissues were assessed by histochemistry or immunohistochemistry (f–i). Representative images of Sirius Red staining (f) and quantification of the percentage (%) of Sirius Red-positive area (g). Representative images of anti-α-SMA immunohistochemistry (h, black arrows exemplify anti-α-SMA signals) and quantification of the percentage (%) of α-SMA-positive area (i). Data are presented as mean ± SEM; *P < 0.05 (Student’s t-test). Cryosections of the liver tissues were examined by the immunofluorescence co-staining of TIMP1 and α-SMA (j, k). Representative images were shown (j). White arrowheads exemplify anti-TIMP1 signals. The mean fluorescence intensity of anti-TIMP1 signals was quantified (k). Data are presented as mean ± SEM; *P < 0.05 (Student’s t-test). mRNA levels of fibrosis-related genes in the liver tissues were examined by qPCR (l). Data are presented as mean ± SEM; *P < 0.05, n.s. not significant (two-way ANOVA test). n = 5 for control Esr1^fl/fl or Lrat^Cre;Esr1^fl/fl mice under the NCD condition; n = 11 for control Esr1^fl/fl mice and n = 13 for Lrat^Cre;Esr1^fl/fl mice under the MCD condition. m Lrat^Cre;RCL-ChR2(H134R)/EYFP^+/– female mice were subjected to liver fibrosis. HSCs were then FACS-sorted from the liver tissues and processed for anti-ESR1 ChIP-seq. Genomic browser tracks of ESR1-binding sites at the loci of fibrosis-related genes were shown. n HSCs were FACS-sorted from the liver tissues of C57BL/6 wild-type female mice for in vitro culture. The cells were treated with the control vehicle (DMSO) or 17β-estradiol (β-E2), and mRNA levels of fibrosis-related genes were profiled by RNA-seq. n = 2 for each condition, *q < 0.05. o Diagram of ESR1 signaling in HSCs to mitigate liver fibrosis.