Curcumol attenuates liver sinusoidal endothelial cell angiogenesis via regulating Glis-PROX1-HIF-1α in liver fibrosis

Curcumol: a review of its pharmacology, pharmacokinetics, drug delivery systems, structure-activity relationships, and potential applications

Curcumol (Cur), a guaiane-type sesquiterpenoid hemiketal, is an important and representative bioactive component extracted from the essential oil of the rhizomes of Curcumae rhizoma which is also known as "Ezhu" in traditional Chinese medicine. Recently, Cur has received considerable attention from the research community due to its favorable pharmacological activities, including anti-cancer, hepatoprotective, anti-inflammatory, anti-viral, anti-convulsant, and other activities, and has also exerted therapeutic effect on various cancers, liver diseases, inflammatory diseases, and infectious diseases. Pharmacokinetic studies have shown that Cur is rapidly distributed in almost all organs of rats after intragastric administration with high concentrations in the small intestine and colon. Several studies focusing on structure-activity relationship (SAR) of Cur have shown that some Cur derivatives, chemically modified at C-8 or C-14, exhibited more potent anti-cancer activity and lower toxicity than Cur itself. This review aims to comprehensively summarize the latest advances in the pharmacological and pharmacokinetic properties of Cur in the last decade with a focus on its anti-cancer and hepatoprotective potentials, as well as the research progress in drug delivery system and potential applications of Cur to date, to provide researchers with the latest information, to highlighted the limitations of relevant research at the current stage and the aspects that should be addressed in future research. Our results indicate that Cur and its derivatives could serve as potential novel agents for the treatment of a variety of diseases, particularly cancer and liver diseases.

Research Progress on Sesquiterpenoids of Curcumae Rhizoma and Their Pharmacological Effects

Curcumae Rhizoma, a traditional Chinese medicine with a wide range of pharmacological activities, is obtained from the dried rhizomes of Curcuma phaeocaulis VaL., Curcuma kwangsiensis S. G. Lee et C. F. Liang, and Curcuma wenyujin Y. H. Chen et C. Ling. Sesquiterpenoids and curcuminoids are found to be the main constituents of Curcumae Rhizoma. Sesquiterpenoids are composed of three isoprene units and are susceptible to complex transformations, such as cyclization, rearrangement, and oxidation. They are the most structurally diverse class of plant-based natural products with a wide range of biological activities and are widely found in nature. In recent years, scholars have conducted abundant studies on the structures and pharmacological properties of components of Curcumae Rhizoma. This article elucidates the chemical structures, medicinal properties, and biological properties of the sesquiterpenoids (a total of 274 compounds) isolated from Curcumae Rhizoma. We summarized extraction and isolation methods for sesquiterpenoids, established a chemical component library of sesquiterpenoids in Curcumae Rhizoma, and analyzed structural variances among sesquiterpenoids sourced from Curcumae Rhizoma of diverse botanical origins. Furthermore, our investigation reveals a diverse array of sesquiterpenoid types, encompassing guaiane-type, germacrane-type, eudesmane-type, elemane-type, cadinane-type, carane-type, bisabolane-type, humulane-type, and other types, emphasizing the relationship between structural diversity and activity. We hope to provide a valuable reference for further research and exploitation and pave the way for the development of new drugs derived from medicinal plants.

Curcumol Attenuates Portal Hypertension and Collateral Shunting Via Inhibition of Extrahepatic Angiogenesis in Cirrhotic Rats

Liver cirrhosis can cause disturbances in blood circulation in the liver, resulting in impaired portal blood flow and ultimately increasing portal venous pressure. Portal hypertension induces portal-systemic collateral formation and fatal complications. Extrahepatic angiogenesis plays a crucial role in the development of portal hypertension. Curcumol is a sesquiterpenoid derived from the rhizome of Curcumae Rhizoma and has been confirmed to alleviate liver fibrosis by inhibiting angiogenesis. Therefore, our study was designed to explore the effects of curcumol on extrahepatic angiogenesis and portal hypertension. To induce cirrhosis, Sprague Dawley rats underwent bile duct ligation (BDL) surgery. Rats received oral administration with curcumol (30 mg/kg/d) or vehicle (distilled water) starting on day 15 following surgery, when BDL-induced liver fibrosis had developed. The effect of curcumol was assessed on day 28, which is the typical time of BDL-induced cirrhosis. The results showed that curcumol markedly reduced portal pressure in cirrhotic rats. Curcumol inhibited abnormal splanchnic inflow, mitigated liver injury, improved liver fibrosis, and attenuated portal-systemic collateral shunting in cirrhotic rats. These protective effects were partially attributed to the inhibition on mesenteric angiogenesis by curcumol. Mechanically, curcumol partially reversed the BDL-induced activation of the JAK2/STAT3 signaling pathway in cirrhotic rats. Collectively, curcumol attenuates portal hypertension in liver cirrhosis by suppressing extrahepatic angiogenesis through inhibiting the JAK2/STAT3 signaling pathway.

Liver sinusoidal endothelial cells as potential drivers of liver fibrosis (Review)

Liver fibrosis due to viral or metabolic chronic liver diseases is a major challenge of global health. It is a critical pre‑stage condition of severe hepatopathy, characterized by excessive accumulation of extracellular matrix components and ongoing chronic inflammation. To date, early prevention of liver fibrosis remains challenging. As the most abundant non‑parenchymal hepatic cell population, liver sinusoidal endothelial cells (LSECs) are stabilizers that maintain the intrahepatic environment. Notably, LSECs dysfunction appears to be implicated in the progression of liver fibrosis via numerous mechanisms. Following sustained liver injury, they lose their fenestrae (cytoplasmic pores) and change their crosstalk with other cellular interactions in the hepatic blood environment. LSEC‑targeted therapy has shown promising effects on fibrosis resolution, opening up new opportunities for anti‑fibrotic therapy. In light of this, the present study summarized changes in LSECs during liver fibrosis and their interactions with hepatic milieu, as well as possible therapeutic approaches that specially target LSECs.

The Mechanism of Hepatic Encephalopathy Induced by Thioacetamide Based on Metabolomics and Proteomics: A Preliminary Study

Hepatic encephalopathy (HE) is a central nervous system dysfunction syndrome caused by acute and chronic liver failure or various portal systemic shunt disorders. HE arises from metabolic disorder and excludes other known types of encephalopathy. HE is a major cause of death in people with liver disease. Early diagnosis and timely treatment are key to improving HE prognosis. Herein, we established a model of HE and performed metabolomics to identify 50 significantly differential metabolites between the HE group and control group. The main metabolic pathways associated with these differential metabolites were the purine metabolism, pyrimidine metabolism, aminoacyl tRNA biosynthesis, and glucose metabolism. Through proteomics analysis, we identified 226 significantly differential proteins (52 up-regulated and 174 down-regulated). The main (Kyoto Encyclopedia of Genes and Genomes) enrichment pathways were the Staphylococcus aureus infection, vitamin digestion and absorption, and complement and coagulation cascades. Through the conjoint analysis of proteomics and metabolomics, the differentially present proteins and metabolites were found to be involved in vitamin digestion and absorption, and ferroptosis pathways. In HE, malondialdehyde was significantly elevated, but glutathione was significantly diminished, and the redox balance was destroyed, thus leading to changes in proteins' levels associated with the ferroptosis pathway. In conclusion, this study preliminarily explored the molecular and metabolic mechanisms underlying HE.

A novel mechanistic approach for the anti-fibrotic potential of rupatadine in rat liver via amendment of PAF/NF-ĸB p65/TGF-β1 and hedgehog/HIF-1α/VEGF trajectories

Hepatic fibrosis is one of the major worldwide health concerns which requires tremendous research due to the limited outcomes of the current therapies. The present study was designed to assess, for the first time, the potential therapeutic effect of rupatadine (RUP) in diethylnitrosamine (DEN)-induced liver fibrosis and to explore its possible mechanistic actions. For the induction of hepatic fibrosis, rats were treated with DEN (100 mg/kg, i.p.) once weekly for 6 consecutive weeks, and on the 6th week, RUP (4 mg/kg/day, p.o.) was administered for 4 weeks. Treatment with RUP ameliorated changes in body weights, liver indices, liver function enzymes, and histopathological alterations induced by DEN. Besides, RUP amended oxidative stress, which led to the inhibition of PAF/NF-κB p65-induced inflammation, and, subsequently, prevention of TGF-β1 elevation and HSCs activation as indicated by reduced α-SMA expression and collagen deposition. Moreover, RUP exerted significant anti-fibrotic and anti-angiogenic effects by suppressing Hh and HIF-1α/VEGF signaling pathways. Our results highlight, for the first time, a promising anti-fibrotic potential of RUP in rat liver. The molecular mechanisms underlying this effect involve the attenuation of PAF/NF-κB p65/TGF-β1 and Hh pathways and, subsequently, the pathological angiogenesis (HIF-1α/VEGF).

Safety Evaluation of Curcumol by a Repeated Dose 28-Day Oral Exposure Toxicity Study in Rats

Curcumol, a natural product isolated from the traditional Chinese medicine Rhizoma curcumae, possesses various potential therapeutic values in many diseases. However, evidence of its toxicological profile is currently lacking. In this study, a repeated toxicity study of curcumol was conducted for the first time. SD rats were exposed to doses of 250, 500, 1000 mg/kg in a selected dose formulation for 28 days through oral administration. The potential toxic effects of curcumol on the blood system were observed and further validated in vivo and in vitro. Moreover, other hematology and biochemistry parameters as well as the weight of organs were altered, but no related histopathological signs were observed, indicating these changes were not regarded as toxicologically relevant. Our current findings provide a complete understanding of the safety profile of curcumol, which may contribute to its further study of investigational new drug application.

Curcumae rhizoma and its major constituents against hepatobiliary disease: Pharmacotherapeutic properties and potential clinical applications

BACKGROUND

Hepatobiliary disease currently serves as an urgent health issue in public due to health-modulating factors such as extension of life expectancy, increasingly sedentary lifestyles and over-nutrition. A definite treatment remains lacking owing to different stages of the disease itself and its intricate pathogenesis. Traditional Chinese medicine (TCM) has been gradually popularized in clinic with the satisfactory efficacy and good safety. Curcumae Rhizoma (called E Zhu, EZ in Chinese) is a representative herb, which has been used to treat hepatobiliary disease for thousands of years.

PURPOSE

To systematically summarize the recent research advances on the pharmacological activities of EZ and its constituents, explain the underlying mechanisms of preventing and treating hepatobiliary diseases, and assess the shortcomings of existing work. Besides, ethnopharmacology, phytochemicals, and toxicology of EZ have been researched.

METHODS

The information about EZ was collected from various sources including classic books about Chinese herbal medicine, and scientific databases including Web of Science, PubMed, ScienceDirect, Springer, ACS, SCOPUS, CNKI, CSTJ, and WANFANG using keywords given below and terms like pharmacological and phytochemical details of this plant.

RESULTS

The chemical constituents isolated and identified from EZ, such as terpenoids including β-elemene, furanodiene, germacrone, etc. and curcuminoids including curcumin, demethoxycurcumin, bisdemethoxycurcumin, etc. prove to have hepatoprotective effect, anti-liver fibrotic effect, anti-fatty liver effect, anti-liver neoplastic effect, and cholagogic effect through TGF-β1/Smad, JNK1/2-ROS, NF-κB and other anti-inflammatory and antioxidant signaling pathways. Also, EZ is often combined with other Chinese herbs in the treatment of hepatobiliary diseases with good clinical efficacy and no obvious adverse reactions.

CONCLUSION

It provides a preclinical basis for the efficacy of EZ as an effective therapeutic agent for the prevention and treatment of hepatobiliary diseases. Even so, the further studies still needed to alleviate hepatotoxicity and expand clinical application.

Pathogenesis of Liver Fibrosis and Its TCM Therapeutic Perspectives

Liver fibrosis is a pathological process of abnormal tissue proliferation in the liver caused by various pathogenic factors, which will further develop into cirrhosis or even hepatocellular carcinoma if liver injury is not intervened in time. As a diffuse progressive liver disease, its clinical manifestations are mostly excessive deposition of collagen-rich extracellular matrix resulting in scar formation due to liver injury. Hepatic fibrosis can be caused by hepatitis B and C, fatty liver, alcohol, and rare diseases such as hemochromatosis. As the metabolic center of the body, the liver regulates various vital activities. During the development of fibrosis, it is influenced by many other factors in addition to the central event of hepatic stellate cell activation. Currently, with the increasing understanding of TCM, the advantages of TCM with multiple components, pathways, and targets have been demonstrated. In this review, we will describe the factors influencing liver fibrosis, focusing on the effects of cells, intestinal flora, iron death, signaling pathways, autophagy and angiogenesis on liver fibrosis, and the therapeutic effects of herbal medicine on liver fibrosis.

Immune and Metabolic Alterations in Liver Fibrosis: A Disruption of Oxygen Homeostasis?

According to the WHO, “cirrhosis of the liver” was the 11th leading cause of death globally in 2019. Many kinds of liver diseases can develop into liver cirrhosis, and liver fibrosis is the main pathological presentation of different aetiologies, including toxic damage, viral infection, and metabolic and genetic diseases. It is characterized by excessive synthesis and decreased decomposition of extracellular matrix (ECM). Hepatocyte cell death, hepatic stellate cell (HSC) activation, and inflammation are crucial incidences of liver fibrosis. The process of fibrosis is also closely related to metabolic and immune disorders, which are usually induced by the destruction of oxygen homeostasis, including mitochondrial dysfunction, oxidative stress, and hypoxia pathway activation. Mitochondria are important organelles in energy generation and metabolism. Hypoxia-inducible factors (HIFs) are key factors activated when hypoxia occurs. Both are considered essential factors of liver fibrosis. In this review, the authors highlight the impact of oxygen imbalance on metabolism and immunity in liver fibrosis as well as potential novel targets for antifibrotic therapies.

Screening of blood-activating active components from Curcuma wenyujin Y.H. Chen et C. Ling rhizome based on spectrum-effect relationship analysis and network pharmacology

Curcuma wenyujin Y.H. Chen et C. Ling rhizome (also called EZhu in China) has long been used as plant medicine for its traditional effect on promoting blood circulation and remove blood stasis. However, the active components of EZhu are still unclear at present. This research is managed to investigate the pharmacodynamics material basis on removing blood stasis of EZhu by exploring the spectrum-effect relationship between UPLC-Q/TOF-MS fingerprints and pharmacologic actions. Hemorheology and related functional parameters were detected to evaluate the pharmacologic actions of EZhu. Relative content Changes of components in rat plasma were detected by UPLC-Q/TOF-MS. A compound-target-pathway network was built to predict the pharmacological activity of components in plasma. Then, bivariate correlation analysis (BCA) was used to explore the correlation degree between components in plasma and pharmacologic actions of EZhu. In UPLC-Q/TOF-MS fingerprints of rat plasma, 10 prototype components were identified. BCA results show that 8 components were concerned with the pharmacological activity for treating blood stasis syndrome (BSS) in varying degrees (R > 0.5, P < 0.05). Among them, zedoarofuran and curzerenone have shown correlation with more pharmacological indicators. The network predicted that 80 targets were closely related to 10 components, in which 48 targets were connected with 159 metabolic pathways including arachidonic acid metabolism, sphingolipid signaling pathway, and linoleic acid metabolism. Overall, this study provided a scientific basis for TCM quality control to ensure its safety and efficacy.

Curcumol inhibits ferritinophagy to restrain hepatocyte senescence through YAP/NCOA4 in non-alcoholic fatty liver disease

Objectives

In recent years, cellular senescence has attracted a lot of interest in researchers due to its involvement in non‐alcoholic fatty liver disease (NAFLD). However, the mechanism of cellular senescence is not clear. The purpose of this study was to investigate the effect of curcumol on hepatocyte senescence in NAFLD and the molecular mechanisms implicated.

Materials and methods

LVG Golden Syrian hamsters, C57BL/6J mice and human hepatocyte cell line LO2 were used. Cellular senescence was assessed by analyses of senescence marker SA‐β‐gal, p16 and p21, H3K9me3, γ‐H2AX and telomerase activity.

Results

The results showed that curcumol could inhibit hepatocyte senescence in both in vivo and in vitro NAFLD models, and the mechanism might be related to its regulation of ferritinophagy and subsequent alleviation of iron overload. Moreover, overexpression of nuclear receptor coactivator 4 (NCOA4) weakened the effect of curcumol on ferritinophagy‐mediated iron overload and cellular senescence. Furthermore, we demonstrated that curcumol reduced the expression of NCOA4 by Yes‐associated protein (YAP). In addition, depression of YAP could impair the effect of curcumol on iron overload and cellular senescence.

Conclusion

Our results clarified the mechanism of curcumol inhibition of hepatocyte senescence through YAP/NCOA4 regulation of ferritinophagy in NAFLD. These findings provided a promising option of curcumol to regulate cellular senescence by target YAP/NCOA4 for the treatment of NAFLD.

EZH2-mediated inhibition of KLF14 expression promotes HSCs activation and liver fibrosis by downregulating PPARγ

OBJECTIVES

Induction of deactivation and apoptosis of hepatic stellate cells (HSCs) are principal therapeutic strategies for liver fibrosis. Krüppel-like factor 14 (KLF14) regulates various biological processes, however, roles, mechanisms and implications of KLF14 in liver fibrosis are unknown.

MATERIALS AND METHODS

KLF14 expression was detected in human, rat and mouse fibrotic models, and its effects on HSCs were assessed. Chromatin immunoprecipitation assays were utilized to investigate the binding of KLF14 to peroxisome proliferator-activated receptor γ (PPARγ) promoter, and the binding of enhancer of zeste homolog 2 (EZH2) to KLF14 promoter. In vivo, KLF14-overexpressing adenovirus was injected via tail vein to thioacetamide (TAA)-treated rats to investigate the role of KLF14 in liver fibrosis progression. EZH2 inhibitor EPZ-6438 was utilized to treat TAA-induced rat liver fibrosis.

RESULTS

KLF14 expression was remarkably decreased in human, rat and mouse fibrotic liver tissues. Overexpression of KLF14 increased LD accumulation, inhibited HSCs activation, proliferation, migration and induced G2/M arrest and apoptosis. Mechanistically, KLF14 transactivated PPARγ promoter activity. Inhibition of PPARγ blocked the suppressive role of KLF14 overexpression in HSCs. Downregulation of KLF14 in activated HSCs was mediated by EZH2-regulated histone H3 lysine 27 trimethylation. Adenovirus-mediated KLF14 overexpression ameliorated TAA-induced rat liver fibrosis in PPARγ-dependent manner. Furthermore, EPZ-6438 dramatically alleviated TAA-induced rat liver fibrosis. Importantly, KLF14 expression was decreased in human with liver fibrosis, which was significantly correlated with EZH2 upregulation and PPARγ downregulation.

CONCLUSIONS

KLF14 exerts a critical anti-fibrotic role in liver fibrosis, and targeting the EZH2/KLF14/PPARγ axis might be a novel therapeutic strategy for liver fibrosis.

The role of liver sinusoidal endothelial cells in cancer liver metastasis

Liver sinusoidal endothelial cells (LSECs) are the gatekeeper cells in the liver, contributing critical roles in liver physiological and pathological changes. Factors such as dietary macronutrients, toxins, and aging impact LSEC fenestration. Defenestration of LSECs changes their phenotype and function. Under liver injury, capillarized LSECs promote hepatic stellate cells (HSCs) activation and fibrogenesis, while decapillarized LSECs protect the activation of HSCs and liver injury. The expression of chemokines, such as CXCL9 and CXCL16, changes and impacts the infiltration of immune cells in the liver during disease progression, including hepatocellular carcinoma (HCC). As the largest solid organ, liver is one of the most favorable organs into where tumor cells metastasize. The increased interaction and adhesion of circulating tumor cells (CTCs) with LSECs in the local microenvironment and LSEC-induced tolerance of immunity promote cancer liver metastasis. Several strategies can be applied to target LSEC to modulate their function to prevent cancer liver metastasis, including gut microbiota modulation, microRNA therapy, and medical treatment. Delivery of different treatment agents with nanoparticles may promote precise target treatment. Overall, targeting LSECs is a potential strategy for treatment of early liver diseases and prevention of cancer liver metastasis.

The roles and mechanisms of hypoxia in liver fibrosis

Liver fibrosis occurs in response to any etiology of chronic liver injury. Lack of appropriate clinical intervention will lead to liver cirrhosis or hepatocellular carcinoma (HCC), seriously affecting the quality of life of patients, but the current clinical treatments of liver fibrosis have not been developed yet. Recent studies have shown that hypoxia is a key factor promoting the progression of liver fibrosis. Hypoxia can cause liver fibrosis. Liver fibrosis can, in turn, profoundly further deepen the degree of hypoxia. Therefore, exploring the role of hypoxia in liver fibrosis will help to further understand the process of liver fibrosis, and provide the theoretical basis for its diagnosis and treatment, which is of great significance to avoid further deterioration of liver diseases and protect the life and health of patients. This review highlights the recent advances in cellular and molecular mechanisms of hypoxia in developments of liver fibrosis.

Ginsenoside Rg3 inhibits pulmonary fibrosis by preventing HIF-1α nuclear localisation

Background

Excessive fibroblast proliferation during pulmonary fibrosis leads to structural abnormalities in lung tissue and causes hypoxia and cell injury. However, the mechanisms and effective treatment are still limited.

Methods

In vivo, we used bleomycin to induce pulmonary fibrosis in mice. IHC and Masson staining were used to evaluate the inhibitory effect of ginsenoside Rg3 in pulmonary fibrosis. In vitro, scanning electron microscopy, transwell and wound healing were used to evaluate the cell phenotype of LL 29 cells. In addition, biacore was used to detect the binding between ginsenoside Rg3 and HIF-1α.

Results

Here, we found that bleomycin induces the activation of the HIF-1α/TGFβ1 signalling pathway and further enhances the migration and proliferation of fibroblasts through the epithelial mesenchymal transition (EMT). In addition, molecular docking and biacore results indicated that ginsenoside Rg3 can bind HIF-1α. Therefore, Ginsenoside Rg3 can slow down the progression of pulmonary fibrosis by inhibiting the nuclear localisation of HIF-1α.

Conclusions

This finding suggests that early targeted treatment of hypoxia may have potential value in the treatment of pulmonary fibrosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01426-5.

Autophagy-induced p62 accumulation is required for curcumol to regulate KLF5-mediated angiogenesis in liver sinusoidal endothelial cells

Liver pathological angiogenesis is considered to be one of the key events in the development of liver fibrosis. Autophagy is a defense and stress regulation mechanism. However, whether autophagy regulates pathological angiogenesis in liver fibrosis is still questionable. Here, we aimed to study how curcumol regulated liver sinusoidal endothelial cells (LSECs) angiogenesis through autophagy. We found that curcumol (10, 20 and 40 μM) could inhibit the expression of angiogenesis markers in the LSECs. Importantly, we showed that curcumol might influence LSEC pathological angiogenesis by regulating autophagy level. Furthermore, we indicated that the transcription factor Krüppel-like factor 5 (KLF5) was considered as a key target for curcumol to regulate LSEC angiogenesis. Interestingly, we also suggested that autophagy was as a potential mechanism for curcumol to restrain KLF5 expression. Increased autophagy level could impair the suppression effect of curcumol on KLF5. Fascinatingly, our results indicated that curcumol inhibited autophagy and led to p62 accumulation, which might be a regulation mechanism of KLF5 degradation. Finally, in mice liver fibrosis model, we unanimously showed that curcumol (30 mg/kg) inhibited pathological angiogenesis by reducing LSEC autophagy level and suppressing KLF5 expression. Collectively, these results provided a deeper insight into the molecular mechanism of curcumol to inhibit LSEC pathological angiogenesis during liver fibrosis.

Indoleamine 2,3-dioxygenase 1 limits hepatic inflammatory cells recruitment and promotes bile duct ligation-induced liver fibrosis

Liver fibrosis is a course of chronic liver dysfunction, can develop into cirrhosis and hepatocellular carcinoma. Inflammatory insult owing to pathogenic factors plays a crucial role in the pathogenesis of liver fibrosis. Indoleamine 2,3-dioxygenase 1 (IDO1) can affect the infiltration of immune cells in many pathology processes of diseases, but its role in liver fibrosis has not been elucidated completely. Here, the markedly elevated protein IDO1 in livers was identified, and dendritic cells (DCs) immune-phenotypes were significantly altered after BDL challenge. A distinct hepatic population of CD11c+DCs was decreased and presented an immature immune-phenotype, reflected by lower expression levels of co-stimulatory molecules (CD40, MHCII). Frequencies of CD11c+CD80+, CD11c+CD86+, CD11c+MHCII+, and CD11c+CD40+ cells in splenic leukocytes were reduced significantly. Notably, IDO1 overexpression inhibited hepatic, splenic CD11c+DCs maturation, mature DCs-mediated T-cell proliferation and worsened liver fibrosis, whereas above pathological phenomena were reversed in IDO1-/- mice. Our data demonstrate that IDO1 affects the process of immune cells recruitment via inhibiting DCs maturation and subsequent T cells proliferation, resulting in the promotion of hepatic fibrosis. Thus, amelioration of immune responses in hepatic and splenic microenvironment by targeting IDO1 might be essential for the therapeutic effects on liver fibrosis.

Curcumol attenuates liver sinusoidal endothelial cell angiogenesis via regulating Glis-PROX1-HIF-1α in liver fibrosis

OBJECTIVE

Hepatic sinusoidal angiogenesis owing to dysfunctional liver sinusoidal endothelial cells (LSECs) accompanied by an abnormal angioarchitecture is a symbol related to liver fibrogenesis, which indicates a potential target for therapeutic interventions. However, there are few researches connecting angiogenesis with liver fibrosis, and the deeper mechanism remains to be explored.

MATERIALS AND METHODS

Cell angiogenesis and angiogenic protein were examined in primary LSECs of rats, and multifarious cellular and molecular assays revealed the efficiency of curcumol intervention in fibrotic mice.

RESULTS

We found that curcumol inhibited angiogenic properties through regulating their upstream mediator hypoxia-inducible factor-1α (HIF-1α). The transcription activation of HIF-1α was regulated by hedgehog signalling on the one hand, and the protein stabilization of HIF-1α was under the control of Prospero-related homeobox 1 (PROX1) on the other. A deubiquitinase called USP19 could be recruited by PROX1 and involved in ubiquitin-dependent degradation of HIF-1α. Furthermore, our researches revealed that hedgehog signalling participated in the activation of PROX1 transcription probably in vitro. Besides, curcumol was found to ameliorate liver fibrosis and sinusoid angiogenesis via hedgehog pathway in carbon tetrachloride (CCl₄ ) induced liver fibrotic mice. The protein expression of key regulatory factors, PROX1 and HIF-1α, was consistent with the Smo, the marker protein of Hh signalling pathway.

CONCLUSIONS

In this article, we evidenced that curcumol controlling LSEC-mediated angiogenesis could be a promising therapeutic approach for liver fibrosis.