Deficiency of NALP3 Signaling Impairs Liver Regeneration After Partial Hepatectomy

Inflammatory response is required to proceed the optimal liver regeneration after liver injury. Recent reports demonstrated that inflammasomes are involved in the innate immune response. Several NOD-Like receptors (NLRs) participated in the formation of the inflammasomes. NACHT, LRR, and PYD domain-containing protein 3 (NALP3) belongs to the NLR families and recognizes adenosine triphosphate (ATP), crystals, and reactive oxygen species. The present study examined the effect of inflammasomes on the process of liver regeneration using NALP3 knockout (KO) mice. The activation of inflammasomes in the liver was induced after 70% partial hepatectomy (PHx). The liver-to-body weight ratio was significantly decreased in NALP3-KO mice compared to that in WT mice after PHx. The number of Ki67-positive cells and the expression of Cyclin D1 and E1 after PHx were reduced in NALP3-KO mice compared to WT mice. The expression of pro-inflammatory cytokines (IL-1 beta, TNF-alpha, and IL-6) were decreased in the remnant liver of NALP3-KO mice compared to WT mice. Flow cytometric analysis revealed that the expression of chemokines was decreased and the accumulation of CD11b-positive cells was suppressed in NALP3-KO mice after PHx. The treatment with ATP, which is a ligand to NALP3, increased the liver-to-body weight ratio in WT mice. These results indicate that NALP3 signaling is required for the induction of inflammatory response and the development of liver regeneration after PHx.