NLR Family Pyrin Domain‐Containing 3 Inflammasome Activation in Hepatic Stellate Cells Induces Liver Fibrosis in Mice

Abstract

The NLRP3 inflammasome plays an important role in liver fibrosis development. However, the mechanisms involved in NLRP3-induced fibrosis are unclear. Our aim was to test the hypothesis that the NLRP3 inflammasome in hepatic stellate cells (HSC) can directly regulate their activation and contribute to liver fibrosis. Primary HSC isolated from WT, Nlrp3 , or Nlrp3 knock-in crossed to inducible (estrogen receptor Cre - CreT) mice were incubated with LPS and ATP, or 4OH-tamoxifen, respectively. HSC-specific Nlrp3 -knock-in mice were generated by crossing transgenic mice expressing lecithin retinol acyltransferase (Lrat)-driven Cre and maintained on standard rodent chow for 6 months. Mice were then sacrificed; liver tissue and serum were harvested. Nlrp3 inflammasome activation along with HSC phenotype and fibrosis were assessed by RT-PCR, Western blot, FACS, ELISA, immunofluorescence and immunohistochemistry. Stimulated WT HSC displayed increased levels of NLRP3 inflammasome-induced ROS production and Cathepsin B activity, accompanied by an upregulation of mRNA and protein levels of fibrotic makers, an effect abrogated in Nlrp3 HSC. Nlrp3 CreT HSC also showed elevated mRNA and protein expression of fibrotic markers 24h after inflammasome activation induced with 4OH-tamoxifen. Protein and mRNA expression levels of fibrotic markers were also found to be increased in isolated HSC and whole liver tissue from Nlrp3 Lrat Cre mice compared to WT. Liver sections from 24 week-old Nlrp Lrat Cre mice showed fibrotic changes with increased αSMA and desmin positive cells and collagen deposition, independent of inflammatory infiltrates; these changes were also observed after LPS challenge in 8 week-old Nlrp Lrat Cre mice. Conclusion Our results highlight a direct role for the NLRP3 inflammasome in the activation of HSC directly triggering liver fibrosis. This article is protected by copyright. All rights reserved.

Age-Related Changes in the Gut Microbiota Promote Atrial Fibrillation

“…Besides, the expression levels of brosis-related proteins in CF were also increased. Moreover, recent study showed that the activation of NLRP3-in ammasome in the hepatic stellate cells (HSCs) due to LPS could promote liver brosis also con rmed our ndings [42]. The NLRP3-in ammsome is mainly distributed in macrophage and CF, but less in CM [43], and it can interact with different types of cells [44].…”

Transcriptional Suppression of the NLRP3 Inflammasome and Cytokine Release in Primary Macrophages by Low-Dose Anthracyclines

“…This study established a new field of application for the licensed anti-tumor drug epirubicin as an anti-inflammatory agent, reducing IL-1β and TNF-α release from macrophages when used at low-doses. Given the increasingly recognized role of NLRP3 for the development of liver injury and fibrosis [6,8,10,11], therapeutic interventions focusing on the epigenetic programming of immune cells and the organ-specific inhibition of inflammasomes represent novel anti-inflammatory strategies, which need to be further investigated in the context of fibrogenesis. Furthermore, the anti-inflammatory properties of epirubicin may be an adverse effect in cancer therapy.…”

Involvement of Nucleotide-Binding Oligomerization Domain-Like Receptor Family Pyrin Domain Containing 3 Inflammasome in the Pathogenesis of Liver Diseases

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