Fig 2: AAV-mediated restoration of hepatic MBL expression abrogates the deterioration of liver fibrosis as a result of MBL deficiency. The MBL-/- and WT mice (n = 5 per group) received a pAAV-control or pAAV-MBL vector injection 3 weeks before liver fibrosis establishment. (A) Representative photomicrographs of MBL histologic staining in the liver tissues of WT and MBL-/- mice injected with pAAV-control or pAAV-MBL vectors. (B) The protein levels of MBL in liver tissues were assessed by Western blot analysis. (C) Representative photomicrographs of Sirius Red, Masson’s trichrome, and a-SMA histologic staining in the liver tissues. (D) The mRNA levels of fibrosis-related genes in livers were assessed by quantitative reverse-transcription PCR analysis. Scale bars: 100 µm. Data are presented as means ± SEM. **P < .01, 1-way analysis of variance followed by Tukey post hoc tests for multiple group comparisons. Timp1, tissue inhibitors of metalloproteinase 1.

Fig 3: MBL deficiency leads to decreased frequency of senescent HSCs. The MBL-/- and WT mice (n = 8 per group) were injected with CCl4 for 6 weeks. Representative photomicrographs of (A) SA–ß-gal staining and (B) Ki67 staining in fibrotic livers of WT and MBL-/- mice. Scale bars: 100 µm. (C) Representative immunofluorescence staining of a-SMA (green) and p21 (red) in liver tissues of WT and MBL-/- mice. Scale bars: 50 µm. (D) The mRNA levels of senescence-related genes in primary HSCs of CCl4-treated WT and MBL-/- mice. Data are presented as means ± SEM. *P < .05, **P < .01, Student t test. CCL, chemokine (C-C motif) ligand; CXCL, chemokine (C-X-C motif) ligand; DAPI, 4',6-diamidino-2-phenylindole; HPF, high-power field; IL, interleukin; MMP, matrix metalloproteinase.

Fig 4: MBL deficiency aggravates liver fibrosis. MBL-/- and WT mice (n = 8 per group) were injected with CCl4 for 6 weeks. (A) The serum concentration of ALT, AST, and LDH. (B) Representative photomicrographs of H&E staining in livers of WT and MBL-/- mice with the establishment of liver fibrosis. Representative photomicrographs of (C) Sirius Red and (D) Masson’s trichrome staining in fibrotic livers of WT and MBL-/- mice. The (E) immunohistochemical staining, (F) protein expression, and (G) mRNA levels of a-SMA in liver tissues. (H) The quantitative reverse-transcription PCR analysis of mRNA levels of fibrosis-related genes in primary HSCs from WT and MBL-/- mice. Scale bars: 100 µm. Data are presented as means ± SEM. *P < .05, **P < .01, Student t test. Timp1, tissue inhibitors of metalloproteinase 1.

Fig 5: Restoration of hepatic MBL expression eliminates MBL absence–mediated reduction of senescent HSC frequency. The MBL-/- and WT mice (n = 5 per group) received a pAAV-control or pAAV-MBL vector injection 3 weeks before liver fibrosis establishment. (A) Representative immunofluorescence staining of a-SMA (green) and p21 (red), p16 (red), p-H2.X (red), or Ki67 (red) in liver tissues. (B) The p53 and p21 protein levels in liver tissues were assessed by Western blot analysis. (C) The mRNA levels of senescence-related genes in liver tissues were assessed by quantitative reverse-transcription PCR analysis. Scale bars: 100 µm. Data are presented as means ± SEM. **P < .01, 1-way analysis of variance followed by Tukey post hoc tests for multiple group comparisons. CCL, chemokine (C-C motif) ligand; CXCL, chemokine (C-X-C motif) ligand; DAPI, 4',6-diamidino-2-phenylindole; HPF, high-power field; IL, interleukin; MMP, matrix metalloproteinase.