To clarify the roles of innate immune cells in liver regeneration, here we investigated the alteration in regenerative responses after partial hepatectomy (PH) under selective depletion of natural killer (NK) and/or NKT cells. Male, wild-type (WT; C57Bl/6) and CD1d-knockout (KO) mice were injected with anti-NK1.1 or anti-asialo GM1 antibody, and then underwent the 70% PH. Regenerative responses after PH were evaluated, and hepatic expression levels of cytokines and growth factors were measured by real-time RT-PCR and ELISA. Phosphorylation of STAT3 was detected by Western blotting. Depletion of both NK and NKT cells with an anti-NK1.1 antibody in WT mice caused drastic decreases in bromodeoxyuridine (BrdU) uptake, expression of PCNA and cyclin D1 48 hour after PH. In mice given NK1.1 antibody, increases in hepatic TNFα, IL-6/phospho-STAT3 and hepatocyte growth factor (HGF) levels following PH were also blunted significantly, whereas IFNγ mRNA levels were not different. CD1d-KO mice per se showed normal liver regeneration; however, pretreatment with an anti-asialo GM1 antibody to CD1d-KO mice, resulting in depletion of both NK and NKT cells, also blunted regenerative responses. Collectively, these observations clearly indicated that depletion of both NK and NKT cells by two different ways results in impaired liver regeneration. NK and NKT cells most likely up-regulate TNFα, IL-6/STAT3, and HGF in a coordinate fashion, thus promoting normal regenerative responses in the liver.
- innate immunity
- hepatocyte growth factor (HGF)
- Copyright © 2012, American Journal of Physiology- Gastrointestinal and Liver Physiology