Volume 131, Issue 5, Pages 1573-1583 (November 2006) Activation of Mouse Natural Killer T Cells Accelerates Liver Regeneration After Partial Hepatectomy  Hiroyuki Nakashima, Takuo Inui, Yoshiko Habu, Manabu Kinoshita, Shigeaki Nagao, Atsushi Kawaguchi, Soichiro Miura, Nariyoshi Shinomiya, Hideo Yagita, Shuhji Seki  Gastroenterology  Volume 131, Issue 5, Pages 1573-1583 (November 2006) DOI: 10.1053/j.gastro.2006.08.028 Copyright © 2006 AGA Institute Terms and Conditions

Figure 1 Serum ALT levels and liver histopathology in PHx and sham-operated mice after α-GalCer injection. Young (7-week-old) and aged (50-week-old) mice were subjected to PHx or sham operation, and α-GalCer or vehicle was injected (IV) 48 hours after surgery. Sera were obtained from the retro-orbital sinus of (A) young and (B) aged mice at the indicated hours after α-GalCer or vehicle injection. Data are means ± SE from 5 mice in each group. *P < .05. ––■––, Sham α-GalCer; –□–, PHx α-GalCer; - -□- -, PHx vehicle. (C) The liver of a sham-operated aged mouse injected with α-GalCer shown at low (100×) magnification. (D) The liver of a PHx aged mouse injected with α-GalCer shown at low (100×) magnification. Twenty-four hours after α-GalCer injection, livers were obtained from sham-operated and PHx mice and fixed in 10% formalin. Shown are representative microscopic findings from among 4 mice in each group having similar findings (H&E staining). Gastroenterology 2006 131, 1573-1583DOI: (10.1053/j.gastro.2006.08.028) Copyright © 2006 AGA Institute Terms and Conditions

Figure 2 Reverse-transcription PCR analysis of the TNFR1 and FasL mRNA expression in liver NKT cells. TNFR1 and FasL expression of liver NKT cells from either young (7 weeks) or aged (50 weeks) mice subjected to sham operation or PHx. (A) At 1 hour after injection of either α-GalCer or vehicle, liver MNCs were obtained from mice in each group. NKT cells were purified using a cell sorter after staining with NK1.1 Ab and TCR Ab, and total RNA was extracted. (B) PCR bands of TNFR1 and FasL were quantitated based on the ratio of the signal intensity of the PCR products to those of the internal controls (glyceraldehyde-3-phosphate dehydrogenase), as described in the Materials and Methods section. Data are means ± SE from 4 independent experiments. *P < .05. Gastroenterology 2006 131, 1573-1583DOI: (10.1053/j.gastro.2006.08.028) Copyright © 2006 AGA Institute Terms and Conditions

Figure 3 Surface FasL expression of liver NKT cells. At 1 hour after the α-GalCer or vehicle treatment, liver MNCs of young and aged PHx or sham mice (75 weeks of age) were isolated and subjected to flow cytometric analysis. FasL expression on gated CD1/α-GalCer+ NK1.1+ NKT cells was shown. Anti-TNF Ab was injected 12 hours before α-GalCer injection. The data are representative of 4 independent experiments with similar results. The percentages of FasL expression of old PHX mice with or without TNF Ab are means ± SE from 4 mice. *P < .05, PHx group vs PHx +TNF Ab group. Gastroenterology 2006 131, 1573-1583DOI: (10.1053/j.gastro.2006.08.028) Copyright © 2006 AGA Institute Terms and Conditions

Figure 4 Augmentation of hepatocyte mitosis after α-GalCer injection in PHx mice. (A) The livers were obtained from young (7 weeks) and old mice (50 weeks) at 8 hours after α-GalCer or vehicle injection (44 hours after PHx) and stained with H&E to examine the hepatocyte mitotic figures per 2000 hepatocytes. Data are means ± SE from 5 mice in each group. (B) Time schedule of the examination of hepatocyte mitosis. (C) Mitotic figures and (D) PCNA-positive cells in hepatocytes from aged mice were counted at 2 days (44 h), 4, 6, and 8 days after PHx. Data are means ± SE from 5 to 10 mice in each group. *P < .05, **P < .01. Gastroenterology 2006 131, 1573-1583DOI: (10.1053/j.gastro.2006.08.028) Copyright © 2006 AGA Institute Terms and Conditions

Figure 5 Inhibition of α-GalCer–induced hepatocyte proliferation and liver regeneration in PHx mice either by NK1.1 Ab, anti-TNF Ab, or anti-FasL Ab treatment. Aged (50 weeks) mice were injected twice with NK1.1 Ab (200 μg) or PBS, at 3 days before PHx (IV) and just after PHx (intraperitoneally). PHx mice were injected with anti-TNF Ab or anti-FasL Ab (.5 mg) (PBS as a control) 1 hour before α-GalCer injection. α-GalCer or vehicle was injected into PHx mice 36 hours after PHx. (A) Mitotic figures and (B) PCNA-positive cells were counted at 44 hours after PHx, or 8 hours after α-GalCer injection (n = 5–10 in each mouse group). (C) Weights of remnant livers were measured at indicated days until 8 days after PHx (n = 5–10 in each group). Data are pooled from 3 to 5 independent experiments with 1 to 2 mice per group. *P < .05. (C) ○, Vehicle; ●, α-GalCer; ■, αNK1.1 + α-GalCer; ▲, αTNF + α-GalCer; ▵, αFasL + α-GalCer. Gastroenterology 2006 131, 1573-1583DOI: (10.1053/j.gastro.2006.08.028) Copyright © 2006 AGA Institute Terms and Conditions

Figure 6 Mitotic figures of hepatocytes in the livers of aged mice in each group. Mitotic figures are indicated by white arrowheads. Gastroenterology 2006 131, 1573-1583DOI: (10.1053/j.gastro.2006.08.028) Copyright © 2006 AGA Institute Terms and Conditions

Figure 7 PCNA-positive hepatocytes in the livers of aged mice in each group. Gastroenterology 2006 131, 1573-1583DOI: (10.1053/j.gastro.2006.08.028) Copyright © 2006 AGA Institute Terms and Conditions

Figure 8 (A) The effect of α-GalCer injection on hepatocyte mitosis after PHx in lpr mice. The livers were obtained from MRL+/+ or lpr mice (7 weeks of age) at 8 hours after α-GalCer or vehicle injection (44 hours after PHx) and were stained with H&E to examine the hepatocyte mitotic figures per 2000 hepatocytes. Data are means ± SE from 5 lpr mice and 3 +/+ mice. (B) The effect of anti-TNF Ab and/or anti-FasL Ab pretreatment on hepatocyte mitosis in PHx B6 mice. B6 mice (n = 3) (50 weeks of age) were treated with anti-TNF Ab, anti-FasL Ab, or both Abs (PBS as a control) 1 hour before PHx, and hepatocyte mitosis was examined at 44 hours after PHx without α-GalCer injection. (C) The effect of the depletion of NK cells or of both NK and NKT cells on hepatocyte mitosis in PHx B6 mice. Mice (n = 3) were injected with anti-asialoGM1 Ab (50 μg), anti-NK1.1 Ab (200 μg), or PBS at 3 days before PHx (IV) and just after PHx (intraperitoneally). (D) NKT cell–deficient CD1d-/- mice show decreased hepatocyte mitosis after PHx. CD1d-/- mice (n = 5) and BALB/c mice (n = 5) (7 weeks of age) were examined. (E) bg mice (7 weeks of age) show increased hepatocyte mitosis after PHx, and depletion of NKT and NK cells decreased hepatocyte mitosis. bg mice were injected twice with NK1.1 Ab (200 μg) or PBS, at 3 days before PHx (IV) and just after PHx (intraperitoneally), B6 mice (7 weeks of age) also were injected with PBS. Four mice of each group were examined. *P < .05, **P < .01. Gastroenterology 2006 131, 1573-1583DOI: (10.1053/j.gastro.2006.08.028) Copyright © 2006 AGA Institute Terms and Conditions