Angiocrine signaling in sinusoidal homeostasis and liver diseases.

The hepatic sinusoids are composed of liver sinusoidal endothelial cells (LSECs), which are surrounded by hepatic stellate cells (HSCs) and contain liver-resident macrophages called Kupffer cells, and other patrolling immune cells. All these cells communicate with each other and with hepatocytes to maintain sinusoidal homeostasis and a spectrum of hepatic functions under healthy conditions. Sinusoidal homeostasis is disrupted by metabolites, toxins, viruses, and other pathological factors, leading to liver injury, chronic liver diseases, and cirrhosis. Alterations in hepatic sinusoids are linked to fibrosis progression and portal hypertension. LSECs are crucial regulators of cellular crosstalk within their microenvironment via angiocrine signaling. This review discusses the mechanisms by which angiocrine signaling orchestrates sinusoidal homeostasis, as well as the development of liver diseases. Here, we summarise the crosstalk between LSECs, HSCs, hepatocytes, cholangiocytes, and immune cells in health and disease and comment on potential novel therapeutic methods for treating liver diseases.

Prognostic evaluation and immune infiltration analysis of five bioinformatic selected genes in hepatocellular carcinoma.

Despite the development in hepatocellular carcinoma (HCC) treatment in recent years, the therapeutic outcome of HCC remains unfavourable. This study examines the prognosis of HCC from a genetic level using clinical databases and single-cell data to identify genes with a high prognostic value. Three up-regulated genes (UBE2S, PTTG1, and CDC20) and two down-regulated genes (SOCS2 and DNASE1L3) in HCC tissues were identified. Various analyses confirmed its correlation with tumour stage (p < 0.01) and patient survival time (log-rank p < 0.001). Immune analysis, single-cell analysis, and gene set enrichment analysis (GSEA) were employed to provide insight on how they affect cancer progression, and we observed a close relation between these genes and tumour immune infiltration. Eventually, we constructed a risk score system that risk score = (0.0465) × UBE2S + (0.1851) × CDC20 + (-0.0461) × DNASE1L3 + (-0.2279) × SOCS2 (5-year area under curve = 0.706). The risk score system may serve as an effective novel prognostic system for HCC patients. This study might provide novel ideas for prognostic or therapeutic biomarkers for HCC.

C-C motif chemokine receptor 2 inhibition reduces liver fibrosis by restoring the immune cell landscape.

The accumulation of extracellular matrix (ECM) proteins in the liver leads to liver fibrosis and end-stage liver cirrhosis. C-C motif chemokine receptor 2 (CCR2) is an attractive target for treating liver fibrosis. However, limited investigations have been conducted to explore the mechanism by which CCR2 inhibition reduces ECM accumulation and liver fibrosis, which is the focus of this study. Liver injury and liver fibrosis were induced by carbon tetrachloride (CCl4) in wild-type mice and Ccr2 knockout (Ccr2-/-) mice. CCR2 was upregulated in murine and human fibrotic livers. Pharmacological CCR2 inhibition with cenicriviroc (CVC) reduced ECM accumulation and liver fibrosis in prevention and treatment administration. In single-cell RNA sequencing (scRNA-seq), CVC was demonstrated to alleviate liver fibrosis by restoring the macrophage and neutrophil landscape. CVC administration and CCR2 deletion can also inhibit the hepatic accumulation of inflammatory FSCN1+ macrophages and HERC6+ neutrophils. Pathway analysis indicated that the STAT1, NFκB, and ERK signaling pathways might be involved in the antifibrotic effects of CVC. Consistently, Ccr2 knockout decreased phosphorylated STAT1, NFκB, and ERK in the liver. In vitro, CVC could transcriptionally suppress crucial profibrotic genes (Xaf1, Slfn4, Slfn8, Ifi213, and Il1ß) in macrophages by inactivating the STAT1/NFκB/ERK signaling pathways. In conclusion, this study depicts a novel mechanism by which CVC alleviates ECM accumulation in liver fibrosis by restoring the immune cell landscape. CVC can inhibit profibrotic gene transcription via inactivating the CCR2-STAT1/NFκB/ERK signaling pathways.

STING mediates hepatocyte pyroptosis in liver fibrosis by Epigenetically activating the NLRP3 inflammasome.

The activation of stimulator of interferon genes (STING) and NOD-like receptor protein 3 (NLRP3) inflammasome-mediated pyroptosis signaling pathways represent two distinct central mechanisms in liver disease. However, the interconnections between these two pathways and the epigenetic regulation of the STING-NLRP3 axis in hepatocyte pyroptosis during liver fibrosis remain unknown. STING and NLRP3 inflammasome signaling pathways are activated in fibrotic livers but are suppressed by Sting knockout. Sting knockout ameliorated hepatic pyroptosis, inflammation, and fibrosis. In vitro, STING induces pyroptosis in primary murine hepatocytes by activating the NLRP3 inflammasome. H3K4-specific histone methyltransferase WD repeat-containing protein 5 (WDR5) and DOT1-like histone H3K79 methyltransferase (DOT1L) are identified to regulate NLRP3 expression in STING-overexpressing AML12 hepatocytes. WDR5/DOT1L-mediated histone methylation enhances interferon regulatory transcription factor 3 (IRF3) binding to the Nlrp3 promoter and promotes STING-induced Nlrp3 transcription in hepatocytes. Moreover, hepatocyte-specific Nlrp3 deletion and downstream Gasdermin D (Gsdmd) knockout attenuate hepatic pyroptosis, inflammation, and fibrosis. RNA-sequencing and metabolomics analysis in murine livers and primary hepatocytes show that oxidative stress and metabolic reprogramming might participate in NLRP3-mediated hepatocyte pyroptosis and liver fibrosis. The STING-NLRP3-GSDMD axis inhibition suppresses hepatic ROS generation. In conclusion, this study describes a novel epigenetic mechanism by which the STING-WDR5/DOT1L/IRF3-NLRP3 signaling pathway enhances hepatocyte pyroptosis and hepatic inflammation in liver fibrosis.

Efficient Generation of an Fah/Rag2 Dual-Gene Knockout Porcine Cell Line Using CRISPR/Cas9 and Adenovirus.

The shortage of human hepatocytes continues to be a significant limitation for the widespread application of hepatocyte transplantation and bioartificial liver (BAL) support therapy. Recombinant activation gene 2 (Rag2) and fumarylacetoacetate hydrolase (Fah)-deficient mice could be highly repopulated with human hepatocytes. However, Fah/Rag2-deficient mice can only produce up to 1 × 108 human hepatocytes per mouse. We hypothesized that 2-10 × 1010 human hepatocytes can be produced per Fah/Rag2-deficient pig, which is an adequate supply for hepatocyte transplantation and BAL therapy. In a novel approach, we used stably transfected Cas9 cells and single-guide RNA adenoviruses containing fluorescent reporters to enrich porcine cells with Fah/Rag2 dual gene mutations. This resulted in the construction of Fah/Rag2 double knockout porcine iliac artery endothelial cells, which were subsequently used for generating Fah/Rag2-deficient pigs.