Cell atlas of CCl 4-induced progressive liver fibrosis reveals stage-specific responses

Aberrant differentiation and proliferation of hepatocytes in chronic liver injury and liver tumors

Chronic liver injury induces liver cirrhosis and facilitates hepatocarcinogenesis. However, the effects of this condition on hepatocyte proliferation and differentiation are unclear. We showed that rodent hepatocytes display a ductular phenotype when they are cultured within a collagenous matrix. This process involves transdifferentiation without the emergence of hepatoblastic features and is at least partially reversible. During the ductular reaction in chronic liver diseases with progressive fibrosis, some hepatocytes, especially those adjacent to ectopic ductules, demonstrate ductular transdifferentiation, but the majority of increased ductules originate from the existing bile ductular system that undergoes extensive remodeling. In chronic injury, hepatocyte proliferation is weak but sustained, and most regenerative nodules in liver cirrhosis are composed of clonally proliferating hepatocytes, suggesting that a small fraction of hepatocytes maintain their proliferative capacity in chronic injury. In mouse hepatocarcinogenesis models, hepatocytes activate the expression of various fetal/neonatal genes, indicating that these cells undergo dedifferentiation. Hepatocyte-specific somatic integration of various oncogenes in mice demonstrated that hepatocytes may be the cells of origin for a broad spectrum of liver tumors through transdifferentiation and dedifferentiation. In conclusion, the phenotypic plasticity and heterogeneity of mature hepatocytes are important for understanding the pathogenesis of chronic liver diseases and liver tumors.

Effects of Marine Natural Products on Liver Diseases

The prevention and treatment of liver disease, a class of disease that seriously threatens human health, has always been a hot topic of medical research. In recent years, with the in-depth exploration of marine resources, marine natural products have shown great potential and value in the field of liver disease treatment. Compounds extracted and isolated from marine natural products have a variety of biological activities such as significant antiviral properties, showing potential in the management of alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD), protection of the liver from fibrosis, protection from liver injury and inhibition of the growth of hepatocellular carcinoma (HCC). This paper summarizes the progress of research on marine natural products for the treatment of liver diseases in the past decade, including the structural types of active substances from different natural products and the mechanisms underlying the modulation of different liver diseases and reviews their future prospects.

Gossypetin targets the liver-brain axis to alleviate pre-existing liver fibrosis and hippocampal neuroinflammation in mice

Liver fibrosis occurs in response to chronic damage and inflammation to the liver. Leaving untreated, it can lead to decreased liver function and can eventually progress to cirrhosis, a more advanced and irreversible state of liver damage. Clinical investigations showed that chronic liver disease associated with neurological symptoms including anxiety, depression, and cognitive decline. However, few therapeutic options are available for treating liver and related brain pathologies simultaneously. In this study, we aim to find therapeutic candidates that target the liver-brain axis. Gossypetin, a flavonoid from sedum, shows promising capability in treating liver and brain pathologies in CCl4-induced mouse model. Short term of gossypetin administration is sufficient to ameliorate impaired liver function and pre-existing liver fibrosis, suppress MKK3/6-p38 MAPK and p53 activation, and abolish the activation of hepatic stellate cells and Kupffer cells. Although we observe no neuronal loss in the brain of mice with liver fibrosis, we do observe astrogliosis and microglial activation in certain brain regions, especially the hippocampus. Brief gossypetin administration also shows potential in alleviating neuroinflammation in these regions. These results suggest that gossypetin can target the liver-brain axis and be a promising candidate for treating chronic liver fibrosis patients with neurological symptoms.

Overexpression of wild-type HRAS drives non-alcoholic steatohepatitis to hepatocellular carcinoma in mice

Hepatocellular carcinoma (HCC), a prevalent solid carcinoma of significant concern, is an aggressive and often fatal disease with increasing global incidence rates and poor therapeutic outcomes. The etiology and pathological progression of non-alcoholic steatohepatitis (NASH)-related HCC is multifactorial and multistage. However, no single animal model can accurately mimic the full NASH-related HCC pathological progression, posing considerable challenges to transition and mechanistic studies. Herein, a novel conditional inducible wild-type human HRAS overexpressed mouse model (HRAS-HCC) was established, demonstrating 100% morbidity and mortality within approximately one month under normal dietary and lifestyle conditions. Advanced symptoms of HCC such as ascites, thrombus, internal hemorrhage, jaundice, and lung metastasis were successfully replicated in mice. In-depth pathological features of NASH- related HCC were demonstrated by pathological staining, biochemical analyses, and typical marker gene detections. Combined murine anti-PD-1 and sorafenib treatment effectively prolonged mouse survival, further confirming the accuracy and reliability of the model. Based on protein-protein interaction (PPI) network and RNA sequencing analyses, we speculated that overexpression of HRAS may initiate the THBS1-COL4A3 axis to induce NASH with severe fibrosis, with subsequent progression to HCC. Collectively, our study successfully duplicated natural sequential progression in a single murine model over a very short period, providing an accurate and reliable preclinical tool for therapeutic evaluations targeting the NASH to HCC continuum.

A spatiotemporal atlas of mouse liver homeostasis and regeneration

The mechanism by which mammalian liver cell responses are coordinated during tissue homeostasis and perturbation is poorly understood, representing a major obstacle in our understanding of many diseases. This knowledge gap is caused by the difficulty involved with studying multiple cell types in different states and locations, particularly when these are transient. We have combined Stereo-seq (spatiotemporal enhanced resolution omics-sequencing) with single-cell transcriptomic profiling of 473,290 cells to generate a high-definition spatiotemporal atlas of mouse liver homeostasis and regeneration at the whole-lobe scale. Our integrative study dissects in detail the molecular gradients controlling liver cell function, systematically defining how gene networks are dynamically modulated through intercellular communication to promote regeneration. Among other important regulators, we identified the transcriptional cofactor TBL1XR1 as a rheostat linking inflammation to Wnt/β-catenin signaling for facilitating hepatocyte proliferation. Our data and analytical pipelines lay the foundation for future high-definition tissue-scale atlases of organ physiology and malfunction.

Ginsenoside Rk1 induces autophagy-dependent apoptosis in hepatocellular carcinoma by AMPK/mTOR signaling pathway

Hepatocellular carcinoma (HCC) is the third most lethal cancer in the world. Recent studies have shown that suppression of autophagy plays an important role in the development of HCC. Ginsenoside Rk1 is a protopanaxadiol saponin isolated from ginseng and has a significant anti-tumor effect, but its role and mechanism in HCC are still unclear. In this study, a mouse liver cancer model induced by diethylnitrosamine and carbon tetrachloride (DEN + CCl4) was employed to investigate the inhibitory effect of Rk1 on HCC. The results demonstrate that ginsenoside Rk1 effectively inhibits liver injury, liver fibrosis, and cirrhosis during HCC progression. Transcriptome data analysis of mouse liver tissue reveals that ginsenoside Rk1 significantly regulates the AMPK/mTOR signaling pathway, autophagy pathway, and apoptosis pathway. Subsequent studies show that ginsenoside Rk1 induces AMPK protein activation, upregulates the expression of autophagy marker LC3-II protein to promote autophagy, and then downregulates the expression of Bcl2 protein to trigger a caspase cascade reaction, activating AMPK/mTOR-induced toxic autophagy to promote cells death. Importantly, co-treatment of ginsenoside Rk1 with autophagy inhibitors can inhibit apoptosis of HCC cells, once again demonstrating the ability of ginsenoside Rk1 to promote autophagy-dependent apoptosis. In conclusion, our study demonstrates that ginsenoside Rk1 inhibits the development of primary HCC by activating toxic autophagy to promote apoptosis through the AMPK/mTOR pathway. These findings confirm that ginsenoside Rk1 is a promising new strategy for the treatment of HCC.

Fucoxanthin Enhances the Antifibrotic Potential of Placenta-derived Mesenchymal Stem Cells in a CCl4-induced Mouse Model of Liver

BACKGROUND

The effectiveness of fucoxanthin (Fx) in liver diseases has been reported due to its anti-inflammatory and antifibrotic effects. Mesenchymal stem cells (MSCs)-based therapy has also been proposed as a promising strategy for liver fibrosis treatment. Recent studies have shown that the co-administration of MSCs and drugs demonstrates a pronounced effect on liver fibrosis.

AIM

This study aimed to determine the therapeutic potential of placenta-derived MSCs (PD-MSCs) in combination with Fx to treat liver fibrosis and evaluate their impact on the main links of liver fibrosis pathogenesis.

METHODS

After PD-MSCs isolation and identification, outbred ICR/CD1 mice were divided into five groups: Control group, CCl4 group (CCl4), Fx group (CCl4+Fx), PD-MSCs group (CCl4+MSCs) and cotreatment group (CCl4+MSCs+Fx). Biochemical histopathological investigations were performed. Semiquantitative analysis of the alpha-smooth muscle actin (α-SMA+), matrix metalloproteinases (MMP-9+, MMP-13+), tissue inhibitor of matrix metalloproteinases-1 (TIMP-1+) areas, and the number of positive cells in them were studied by immunohistochemical staining. Transforming growth factor-beta (TGF-β), hepatic growth factor (HGF), procollagen-1 (COL1α1) in liver homogenate and proinflammatory cytokines in blood serum were determined using an enzyme immunoassay.

RESULTS

Compared to the single treatment with PD-MSCs or Fx, their combined administration significantly reduced liver enzyme activity, the severity of liver fibrosis, the proinflammatory cytokine levels, TGF-β level, α-SMA+, TIMP-1+ areas and the number of positive cells in them, and increased HGF level, MMP-13+, and MMP-9+ areas.

CONCLUSION

Fx enhanced the therapeutic potential of PD-MSCs in CCl4-induced liver fibrosis, but more investigations are necessary to understand the mutual impact of PD-MSCs and Fx.

Fatty acid metabolization and insulin regulation prevent liver injury from lipid accumulation in Himalayan marmots

Fat storage and weight gain are dominant traits for hibernating mammals. However, excessive fat accumulation may cause liver damage. Here, we explore the lipid accumulation and metabolic processes of the Himalayan marmot (Marmota himalayana), a hibernating rodent species. We find that the unsaturated fatty acid (UFA) content in food was consistent with a large increase in the body mass of Himalayan marmots. Metagenomic analysis shows that Firmicutes Bacterium CAG:110 plays a synergistic role by synthesizing UFAs, which is demonstrated by fecal transplantation experiments, indicating that the gut microbiome promotes fat storage in Himalayan marmots for hibernation. Microscopic examination results indicate that the risk of fatty liver appears at maximum weight; however, liver function is not affected. Upregulations of UFA catabolism and insulin-like growth factor binding protein genes provide an entry point for avoiding liver injury.