Modulation of hepatic stellate cells and reversibility of hepatic fibrosis

Estrogen alleviates liver fibrosis and restores metabolic homeostasis in ovariectomy-induced liver injury and carbon tetrachloride (CCl4) exposure

AIM

Given estrogen's recognized regulatory influence on diverse metabolic and immune functions, this study sought to explore its potential impact on fibrosis and elucidate the underlying metabolic regulations.

METHODS

Female mice underwent ovary removal surgery, followed by carbon tetrachloride (CCl4) administration to induce liver injury. Biochemical index analysis and histopathological examination were then conducted. The expression levels of alpha-smooth muscle actin (α-SMA), transforming growth factor-β (TGF-β), and collagen type 1 alpha 1 chain (COL1A1) were assessed using western blotting to further elucidate the extent of liver injury. Finally, metabolite extraction and metabolomic analysis were performed to evaluate metabolic changes.

RESULTS

Ovary removal exacerbated CCl4-induced liver damage, while estrogen supplementation provided protection against hepatic changes resulting from OVX. Furthermore, estrogen mitigated liver injury induced by CCl4 treatment in vivo. Estrogen supplementation significantly restored liver damage induced by OVX and CCl4. Comparative analysis revealed significant alterations in pathways including aminoacyl-tRNA biosynthesis, glycine, serine, and threonine metabolism, lysine degradation, and taurine and hypotaurine metabolism in estrogen treatment.

CONCLUSION

Estrogen supplementation alleviates liver injury induced by OVX and CCl4, highlighting its protective effects against fibrosis and associated metabolic alterations.

H3K18 lactylation accelerates liver fibrosis progression through facilitating SOX9 transcription

Liver fibrosis is a significant health concern globally due to its association with severe liver conditions like cirrhosis and liver cancer. Histone lactylation has been implicated in the progression of hepatic fibrosis, but its specific role in liver fibrosis, particularly regarding H3K18 lactylation, remained unclear. To investigate this, we established in vivo and in vitro models of liver fibrosis using carbon tetrachloride (CCl4) injection in rats and stimulation of hepatic stellate cells (HSCs) with TGF-β1, respectively. We found that histone lactylation, particularly H3K18 lactylation, was upregulated in both CCl4-induced rats and TGF-β1-activated HSCs, indicating its potential involvement in liver fibrosis. Further experiments revealed that lactate dehydrogenase A (LDHA) knockdown inhibited H3K18 lactylation and had a beneficial effect on liver fibrosis by suppressing HSC proliferation, migration, and extracellular matrix (ECM) deposition. This suggests that H3K18 lactylation promotes liver fibrosis progression. Chromatin immunoprecipitation (ChIP) and luciferase reporter assays demonstrated that H3K18 lactylation facilitated the transcription of SOX9, a transcription factor associated with fibrosis. Importantly, overexpression of SOX9 counteracted the effects of LDHA silencing on activated HSCs, indicating that SOX9 is downstream of H3K18 lactylation in promoting liver fibrosis. In summary, this study uncovers a novel mechanism by which H3K18 lactylation contributes to liver fibrosis by activating SOX9 transcription. This finding opens avenues for exploring new therapeutic strategies for hepatic fibrosis targeting histone lactylation pathways.

ZNF469 is a profibrotic regulator of extracellular matrix in hepatic stellate cells

Activation of quiescent hepatic stellate cells (HSCs) into proliferative myofibroblasts drives extracellular cellular matrix (ECM) accumulation and liver fibrosis; nevertheless, the transcriptional network that promotes such a process is not completely understood. ZNF469 is a putative C2H2 zinc finger protein that may bind to specific genome sequences. It is found to be upregulated upon HSC activation; however, the molecular function of ZNF469 is completely unknown. Here, we show that knockdown of ZNF469 in primary human HSCs impaired proliferation, migration, and collagen production. Conversely, overexpression of ZNF469 in HSCs yielded the opposite results. Transforming growth factor-β 1 promoted expression of ZNF469 in a Smad3-dependent manner, where the binding of Smad3 was confirmed at the ZNF469 promoter. RNA sequencing data of ZNF469-knockdown HSCs revealed the ECM-receptor interaction, which provides structural and signaling support to cells, was the most affected pathway, and significant downregulation of various collagen and proteoglycan genes was observed. To investigate the function of ZNF469, we cloned a full-length open reading frame of ZNF469 with an epitope tag and identified a nuclear localization of the protein. Luciferase reporter and chromatin immunoprecipitation assays revealed the presence of ZNF469 at the promoter of ECM genes, supporting its function as a transcription factor. Analysis of human fibrotic and cirrhotic tissues showed increased expression of ZNF469 and a positive correlation between expression levels of ZNF469 and ECM genes. Moreover, this observation was similar in other fibrotic organs, including the heart, lung, and skin, suggesting that myofibroblasts from various origins generally require ZNF469 to promote ECM production. Together, this study is the first to reveal the role of ZNF469 as a profibrotic factor in HSCs and suggests ZNF469 as a novel target for antifibrotic therapy.

Macrophage-2-Binding Protein Glycosylation Isomer (M2BPGi) and AGAP Score as Markers of Noninvasive Test for Liver Fibrosis versus FibroScan in Chronic Hepatitis B Patients: A Retrospective Observational Study

Background

Liver biopsy as the gold standard for assessing the degree and diagnosis of fibrosis still has significant drawbacks, which make the emergence of a much less invasive diagnostic marker possible. M2BPGi levels and the AGAP score, the two newest serological markers, are known to have good sensitivity for detecting liver fibrosis. This study is aimed at determining the validity of examining M2BPGi levels and AGAP scores on the Fibroscan examination as markers of noninvasive test for liver fibrosis in chronic hepatitis B patients.

Methods

This is an observational, descriptive study with a retrospective design. This study used secondary data taken from medical records and blood specimen research materials of outpatients at the Hepatology Gastroenterology Polyclinic at a tertiary general hospital in West Java, Indonesia, with a diagnosis of chronic hepatitis B.

Results

There were 109 research subjects included. There were 73 (66.9%) subjects with no- or low-grade fibrosis and 36 (33.1%) with advanced fibrosis. The sensitivity and specificity of the M2BPGi were 88.9% and 61.6% (PPV 55.3%; NPV 91.8%; AUC 0.753), while the AGAP score was 47.2% and 100% (PPV 100%; NPV 79.3%; AUC 0.736). The combined M2BPGi level and the AGAP score showed a sensitivity of 80.9% and a specificity of 100% (PPV 100%; NPV 91.8%; AUC 0.905).

Conclusion

The AGAP score and M2BPGi levels together are a better way to measure the degree of liver fibrosis in people with chronic hepatitis B than either M2BPGi or the AGAP score alone.

Exploring the impact of lipid droplets on the evolution and progress of hepatocarcinoma

Over the past 10 years, the biological role of lipid droplets (LDs) has gained significant attention in the context of both physiological and pathological conditions. Considerable progress has been made in elucidating key aspects of these organelles, yet much remains to be accomplished to fully comprehend the myriad functions they serve in the progression of hepatic tumors. Our current perception is that LDs are complex and active structures managed by a distinct set of cellular processes. This understanding represents a significant paradigm shift from earlier perspectives. In this review, we aim to recapitulate the function of LDs within the liver, highlighting their pivotal role in the pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD) (Hsu and Loomba, 2024) and their contribution to the progression towards more advanced pathological stages up to hepatocellular carcinoma (HC) (Farese and Walther, 2009). We are aware of the molecular complexity and changes occurring in the neoplastic evolution of the liver. Our attempt, however, is to summarize the most important and recent roles of LDs across both healthy and all pathological liver states, up to hepatocarcinoma. For more detailed insights, we direct readers to some of the many excellent reviews already available in the literature (Gluchowski et al., 2017; Hu et al., 2020; Seebacher et al., 2020; Paul et al., 2022).

Farnesoid X receptor modulator 12β-(m-methyl-benzoyl)-11,12-dihydro oleanolic acid represses liver fibrosis by inhibiting ERK/p38 signaling pathways

Liver fibrosis is a common pathological process in the progression of several chronic liver diseases to cirrhosis and hepatocellular carcinoma. Therefore, the development of medications that can repress the progress of liver fibrosis is essential. We discovered that initially, 12β-(m-methyl-benzoyl)-11,12-dihydro oleanolic acid (12d-OA), a farnesoid X receptor (FXR) modulator, possessed potential anti-fibrotic properties. Through an in-depth study, we revealed that 12d-OA not only inhibited the expression of fibrogenic markers in the LX-2 cells and HSC-T6 cells but also exhibited significant protective effects against liver injury and liver fibrosis in bile duct ligation (BDL) rats. Further exploration of its molecular mechanism indicated that 12d-OA exerted antifibrotic activity by inhibiting the extracellular signal-regulated kinase (ERK)/stress-activated protein kinase (p38) signaling pathways. Consequently, the great effects of 12d-OA in vitro and in vivo suggest that it may be a good candidate for liver fibrosis.

Notoginsenoside R1 targets PPAR-γ to inhibit hepatic stellate cell activation and ameliorates liver fibrosis

BACKGROUND

Hepatic fibrosis, a common pathological process that occurs in end-stage liver diseases, is a serious public health problem and lacks effective therapy. Notoginsenoside R1 (NR1) is a small molecule derived from the traditional Chinese medicine Sanqi, exhibiting great potential in treating diverse metabolie disorders. Here we aimed to enquired the role of NR1 in liver fibrosis and its underlying mechanism in hepatoprotective effects.

METHODS

We investigated the anti-fibrosis effect of NR1 using CCl4-induced mouse mode of liver fibrosis as well as TGF-β1-activated JS-1, LX-2 cells and primary hepatic stellate cell. Cell samples treated by NR1 were collected for transcriptomic profiling analysis. PPAR-γ mediated TGF-β1/Smads signaling was examined using PPAR-γ selective inhibitors and agonists intervention, immunofluorescence staining and western blot analysis. Additionally, we designed and studied the binding of NR1 to PPAR-γ using molecular docking.

RESULTS

NR1 obviously attenuated liver histological damage, reduced serum ALT, AST levels, and decreased liver fibrogenesis markers in mouse mode. Mechanistically, NR1 elevated PPAR-γ and decreased TGF-β1, p-Smad2/3 expression. The TGF-β1/Smads signaling pathway and fibrotic phenotype were altered in JS-1 cells after using PPAR-γ selective inhibitors and agonists respectively, confirming PPAR-γ played a pivotal protection role inNR1 treating liver fibrosis. Further molecular docking indicated NR1 had a strong binding tendency to PPAR-γ with minimum free energy.

CONCLUSIONS

NR1 attenuates hepatic stellate cell activation and hepatic fibrosis by elevating PPAR-γ to inhibit TGF-β1/Smads signalling. NR1 may be a potential candidate compound for reliving liver fibrosis.

Exosomal miR-192-5p secreted by bone marrow mesenchymal stem cells inhibits hepatic stellate cell activation and targets PPP2R3A

Bone marrow mesenchymal stem cell (BSMC)-derived extracellular vehicles (EVs) have a pivotal therapeutic potential in hepatic fibrosis (HF). Activation of hepatic stellate cells (HSCs) is the key mechanism in HF progression. Downregulation of miR-192-5p was previously observed in activated HSCs. Nonetheless, the functions of BSMC-derived exosomal miR-192-5p in activated HSCs remain unclear. In this study, transforming growth factor (TGF)-β1 was used to activate HSC-T6 cells to mimic HF in vitro. Characterization of BMSCs and BMSC-derived EVs was performed. Cell-counting kit-8 assay, flow cytometry, and western blotting revealed that TGF-β1 increased cell viability, promoted cell cycle progression, and induced upregulation of fibrosis markers in HSC-T6 cells. Overexpression of miR-192-5p or BMSC-derived exosomal miR-192-5p suppressed TGF-β1-triggered HSC-T6 cell activation. RT-qPCR revealed that protein phosphatase 2 regulatory subunit B'' alpha (PPP2R3A) was downregulated in miR-192-5p-overexpressed HSC-T6 cells. Luciferase reporter assay was used for verifying the relation between miR-192-5p and PPP2R3A, which showed that miR-192-5p targeted PPP2R3A in activated HSC-T6 cells. Collectively, BMSC-derived exosomal miR-192-5p targets PPP2R3A and inhibits activation of HSC-T6 cells.

Role of TRP Channels in Liver-Related Diseases

The liver plays a crucial role in preserving the homeostasis of an entire organism by metabolizing both endogenous and exogenous substances, a process that relies on the harmonious interactions of hepatocytes, hepatic stellate cells (HSCs), Kupffer cells (KCs), and vascular endothelial cells (ECs). The disruption of the liver's normal structure and function by diverse pathogenic factors imposes a significant healthcare burden. At present, most of the treatments for liver disease are palliative in nature, rather than curative or restorative. Transient receptor potential (TRP) channels, which are extensively expressed in the liver, play a crucial role in regulating intracellular cation concentration and serve as the origin or intermediary stage of certain signaling pathways that contribute to liver diseases. This review provides an overview of recent developments in liver disease research, as well as an examination of the expression and function of TRP channels in various liver cell types. Furthermore, we elucidate the molecular mechanism by which TRP channels mediate liver injury, liver fibrosis, and hepatocellular carcinoma (HCC). Ultimately, the present discourse delves into the current state of research and extant issues pertaining to the targeting of TRP channels in the treatment of liver diseases and other ailments. Despite the numerous obstacles encountered, TRP channels persist as an extremely important target for forthcoming clinical interventions aimed at treating liver diseases.

Evolution and Discovery of Matrine Derivatives as a New Class of Anti-Hepatic Fibrosis Agents Targeting Ewing Sarcoma Breakpoint Region 1 (EWSR1)

A series of new tricyclic matrinane derivatives were continuously synthesized and evaluated for their inhibitory effects on genes and proteins related to hepatic fibrosis at the cellular level, including collagen type I α1 chain (COL1A1), α smooth muscle actin (α-SMA), connective tissue growth factor (CTGF), and matrix metalloprotein 2 (MMP-2). Among them, compound 6k exerted an appealing potency and significantly reduced liver injury and fibrosis in both bile duct ligation (BDL) rats and Mdr2 knockout mice. An activity-based protein profiling (ABPP) assay indicated that 6k might directly bind to Ewing sarcoma breakpoint region 1 (EWSR1) to inhibit its function and affect the expression of downstream liver fibrosis-related genes and thus regulate liver fibrosis. These results provided a potential novel target for the treatment of liver fibrosis and powerful information for the development of tricyclic matrinanes into promising anti-hepatic fibrosis agents.

Quantitative image-based collagen structural features predict the reversibility of hepatitis C virus-induced liver fibrosis post antiviral therapies

The novel targeted therapeutics for hepatitis C virus (HCV) in last decade solved most of the clinical needs for this disease. However, despite antiviral therapies resulting in sustained virologic response (SVR), a challenge remains where the stage of liver fibrosis in some patients remains unchanged or even worsens, with a higher risk of cirrhosis, known as the irreversible group. In this study, we provided novel tissue level collagen structural insight into early prediction of irreversible cases via image based computational analysis with a paired data cohort (of pre- and post-SVR) following direct-acting-antiviral (DAA)-based treatment. Two Photon Excitation and Second Harmonic Generation microscopy was used to image paired biopsies from 57 HCV patients and a fully automated digital collagen profiling platform was developed. In total, 41 digital image-based features were profiled where four key features were discovered to be strongly associated with fibrosis reversibility. The data was validated for prognostic value by prototyping predictive models based on two selected features: Collagen Area Ratio and Collagen Fiber Straightness. We concluded that collagen aggregation pattern and collagen thickness are strong indicators of liver fibrosis reversibility. These findings provide the potential implications of collagen structural features from DAA-based treatment and paves the way for a more comprehensive early prediction of reversibility using pre-SVR biopsy samples to enhance timely medical interventions and therapeutic strategies. Our findings on DAA-based treatment further contribute to the understanding of underline governing mechanism and knowledge base of structural morphology in which the future non-invasive prediction solution can be built upon.

Restoration of Sinusoid Fenestrae Followed by Targeted Nanoassembly Delivery of an Anti-Fibrotic Agent Improves Treatment Efficacy in Liver Fibrosis

During the onset of liver fibrosis, capillarized liver sinusoidal endothelial cells (LSECs) limit substance exchange between the blood and the Disse space, further accelerating hepatic stellate cell (HSCs) activation and fibrosis progression. Limited accessibility of therapeutics to the Disse space is often overlooked and remains a major bottleneck for HSCs-targeted therapy in liver fibrosis. Here, an integrated systemic strategy for liver fibrosis treatment is reported, utilizing pretreatment with the soluble guanylate cyclase stimulator, riociguat, followed by insulin growth factor 2 receptor-mediated targeted delivery of the anti-fibrosis agent, JQ1, via peptide-nanoparticles (IGNP-JQ1). The riociguat reversed the liver sinusoid capillarization to maintain a relatively normal LSECs porosity, thus facilitating the transport of IGNP-JQ1 through the liver sinusoid endothelium wall and enhancing the accumulation of IGNP-JQ1 in the Disse space. IGNP-JQ1 is then selectively taken up by activated HSCs, inhibiting their proliferation and decreasing collagen deposition in the liver. The combined strategy results in significant fibrosis resolution in carbon tetrachloride-induced fibrotic mice as well as methionine-choline-deficient-diet-induced nonalcoholic steatohepatitis (NASH) mice. The work highlights the key role of LSECs in therapeutics transport through the liver sinusoid. The strategy of restoring LSECs fenestrae by riociguat represents a promising approach for liver fibrosis treatment.

A comprehensive review of emodin in fibrosis treatment

Emodin is the main pharmacodynamic components of rhubarb, with significant pharmacological effects and clinical efficacy.Emodin has a variety of therapy effects, such as anti-cancer, anti-fibrosis effects, and is widely used to treat encephalitis, diabetic cataract and organ fibrosis. Several studies have shown that emodin has a good treatment effect on organ fibrosis, but the mechanism is complex. Moreover, the evidence of some studies is conflicting and confusing. This paper reviewed the mechanism, pharmacokinetics and toxicology of emodin in fibrosis treatment, and briefly discussed relevant cutting-edge new formulations to improve the efficacy, the result can provide some reference for future study.

SIRT7 affects autophagy and activation of hepatic stellate cells by regulating the acetylation level of high mobility group protein 1

OBJECTIVE

Preventing the progression of hepatic fibrosis is an important strategy to improve the prognosis of liver disease. The purpose of this study was to investigate the role of sirtuin7 (SIRT7) and high mobility group box 1 (HMGB1) acetylation in the occurrence and development of hepatic fibrosis.

MATERIALS AND METHODS

Hepatic fibrosis mice model was induced by CCl₄. TGF-β1 was used to activated quiescent hepatic stellate cell (qHSC) into activated HSC (aHSC). Hematoxylin-eosin evaluated hepatic fibrosis in vivo, and the distribution of α-smooth muscle actin (α-SMA) or HMGB1 was detected by immunohistochemistry or immunofluorescence. The expressions of SIRT7, autophagy related proteins, and HSC activation-related proteins were detected by Western blot. Immunoprecipitation detected the acetylation level of HMGB1. Lysine mutants of HMGB1 were constructed in vitro to explore the acetylation sites of HMGB1.

RESULTS

Hepatocyte autophagy and activation levels were enhanced in CCl₄ group or aHSC group, and the acetylation level of HMGB1 was increased. Nuclear transfer of HMGB1 occurred in aHSC, and HMGB1was mainly distributed in cytoplasm. The expression of SIRT7 in CCl₄ group or aHSC group was most significantly decreased, and knockdown of SIRT7 leads to increased levels of HSCs autophagy and activation. Overexpression of SIRT7 or interference of HMGB1 alone in aHSC can reduce the level of autophagy and activation of aHSC. However, continued overexpression of SIRT7 in shHMGB1-aHSC could not reduce the autophagy and activation levels of aHSC. Among the 11 Flag-HMGB1 mutants, the acetylation level of K86R-Flag-HMGB1 was the lowest. The acetylation level of K86R-Flag-HMGB1 did not change due to SIRT7 downregulation.

CONCLUSION

This study proved that SIRT7 can directly target the K86R site of HMGB1 and participate in regulating the expression and distribution of HMGB1, thus affecting the autophagy and activation level of HSCs.

Anti-liver fibrosis effects of the total flavonoids of litchi semen on CCl4-induced liver fibrosis in rats associated with the upregulation of retinol metabolism

CONTEXT

The litchi semen are traditional medications for treating liver fibrosis (LF) in China. The mechanism remains unclear.

OBJECTIVE

This study investigates the anti-liver fibrotic mechanism of the total flavonoids of litchi semen (TFL).

MATERIALS AND METHODS

Sprague-Dawley rats with carbon tetrachloride-induced LF were treated with TFL (50 and 100 mg/kg) for 4 weeks. The anti-liver fibrotic effects of TFL were evaluated and the underlying mechanisms were investigated via histopathological analysis, proteomic analysis and molecular biology technology.

RESULTS

Significant anti-LF effects were observed in the high-TFL-dose group (TFL-H, p < 0.05). Five hundred and eighty-five and 95 differentially expressed proteins (DEPs) were identified in the LF rat model (M group) and TFL-H group, respectively. The DEPs were significantly enriched in the retinol metabolism pathway (p < 0.0001). The content of 9-cis-retinoic acid (0.93 ± 0.13 vs. 0.66 ± 0.10, p < 0.05, vs. the M group) increased significantly in the TFL-H group. The upregulation of RXRα (0.50 ± 0.05 vs. 0.27 ± 0.13 protein, p < 0.05), ALDH2 (1.24 ± 0.09 vs. 1.04 ± 0.08 protein, p < 0.05), MMP3 (0.89 ± 0.02 vs. 0.61 ± 0.12 protein, p < 0.05), Aldh1a7 (0.20 ± 0.03 vs. 0.03 ± 0.00 mRNA, p < 0.05) and Aox3 (0.72 ± 0.14 vs. 0.05 ± 0.01 mRNA, p < 0.05) after TFL treatment was verified.

CONCLUSIONS

TFL exhibited good anti-liver fibrotic effects, which may be related to the upregulation of the retinol metabolism pathway. TFL may be promising anti-LF agents with potential clinical application prospects.

Curcumol alleviates liver fibrosis through inducing autophagy and ferroptosis in hepatic stellate cells

To explore the effect of curcumol on autophagy and ferroptosis of hepatic stellate cells, and to clarify the molecular mechanism of its anti-hepatic fibrosis. In the present study, we report that curcumol promotes the death of activated HSCs and reduces the deposition of extracellular matrix. Interestingly, curcumol treatment can trigger ferroptosis to eliminate activated HSCs characterized by iron overload, lipid ROS accumulation, glutathione depletion, and lipid peroxidation. Curcumol promotes HSC autophagy, which may be the key mechanism for its induction of ferroptosis. It is worth noting that the upregulation of nuclear receptor coactivator 4 (NCOA4) may play a key molecular mechanism. NCOA4 mediates the release of iron ions and induces the occurrence of ferroptosis. Overall, curcumol promotes autophagy in hepatic stellate cells, mediates the degradation of NCOA4 and FTH1 complexes, releases iron ions, leads to iron overload, and induces ferroptosis, which may be an important mechanism for its anti-hepatic fibrosis effect.

A, Venkidasamy B, Cespedes-Acuna CL, Nile SH, Yan G, Zheng H. Pien-Tze-Huang alleviates CCl4-induced liver fibrosis through the inhibition of HSC autophagy and the TGF-β1/Smad2 pathway

Ethnopharmacological relevance: Pien-Tze-Huang (PZH)—a traditional Chinese medicine (TCM) compound—has been employed to treat various liver inflammation and tumors for over 10 decades. Interestingly, most of the pharmacological effects had been validated and explored toward liver ailment along with pro-inflammatory conditions and cancer at the cellular and molecular level to date.

Aim of the study: The present study aimed to investigate the therapeutic effect of PZH on autophagy and TGF-β1 signaling pathways in rats with liver fibrosis and hepatic stellate cell line (HSC).

Materials and methods: Male SD rats with carbon tetrachloride (CCl4)-induced liver fibrosis were used as the animal model. Next, PZH treatment was given for 8 weeks. Afterward, the therapeutic effects of PZH were analyzed through a hepatic tissue structure by hematoxylin-eosin (H&E), Van Gieson (VG) staining, and transmission electron microscopy (TEM), activity of ALT and AST by enzyme-associated immunosorbent assay as well. Subsequently, mRNA and protein expression were examined by quantitative polymerase chain reaction (qPCR), Western blotting, and immunohistochemistry (IHC). Then, the cell vitality of PZH-treated HSC and the expression of key molecules prevailing to autophagy were studied in vitro. Meanwhile, SM16 (a novel small molecular inhibitor which inhibits TGFβ-induced Smad2 phosphorylation) was employed to confirm PZH’s effects on the proliferation and autophagy of HSC.

Results: PZH pharmacologically exerted anti-hepatic fibrosis effects as demonstrated by protecting hepatocytes and improving hepatic function. The results revealed the reduced production of extracellular collagen by adjusting the balance of matrix metalloproteinase (MMP) 2, MMP9, and tissue inhibitor of matrix metalloproteinase 1 (TIMP1) in PZH-treated CCl4-induced liver fibrosis. Interestingly, PZH inhibited the activation of HSC by down-regulating TGF-β1 and phosphorylating Smad2. Furthermore, PZH down-regulated yeast Atg6 (Beclin-1) and microtubule-associated protein light chain 3 (LC3) toward suppressing HSC autophagy, and PZH exhibited similar effects to that of SM16.

Conclusion: To conclude, PZH alleviated CCl4-induced liver fibrosis to reduce the production of extracellular collagen and inhibiting the activation of HSC. In addition, their pharmacological mechanisms related to autophagy and TGF-β1/Smad2 signaling pathways were revealed for the first time.

Bone marrow mesenchymal stem cells inhibit hepatic fibrosis via the AABR07028795.2/rno-miR-667-5p axis

Background

The mechanism of bone marrow mesenchymal stem cells (BMSCs) in treating hepatic fibrosis remains unclear.

Methods

TGF-β1-induced hepatic stellate cell (HSC)-T6 and CCl4-induced hepatic fibrosis rats were treated with BMSCs. HSC-T6 cell activity was determined using the cell counting kit-8 assay, and the histology change was evaluated using hematoxylin and eosin and Masson staining. The expression of fibrosis markers was determined using real-time quantitative PCR, Western blotting, and immunocytochemistry. RNA sequencing (RNA-seq) was used to screen the lncRNAs involved in the effect of BMSCs in fibrosis, and the function of fibrosis-associated lncRNA in fibrosis histology change and fibrosis marker expression was investigated. The potential miRNA target of lncRNA was predicted using R software. The interaction between lncRNA and miRNA was verified using luciferase report system and RNA immunoprecipitation (RIP) in 293T and HSC-T6 cells.

Results

BMSC attenuated TGF-β1-induced HSC-T6 activation and suppressed the expression of fibrosis-associated gene (MMP2, Collagen I, and αSMA) expression at the transcription and translation levels. BMSC treatment also improves hepatic fibrosis in rats with CCl4-induced fibrosis by decreasing the expression of fibrosis-associated genes and suppressing collagen deposition in the liver. RNA-seq revealed that AABR07028795.2 (lnc-BIHAA1) was downregulated in the TGF-β1-induced HSC-T6 after treatment with BMSCs as compared with those in TGF-β1-induced HSC-T6, and subsequently, functional analysis showed that lnc-BIHAA1 plays a beneficial role in suppressing hepatic fibrosis. Luciferase activity assay and RIP revealed that lnc-BIHAA1 interacted with the miRNA, rno-miR-667-5p, functioning as a fibrosis phenotype suppressor in TGF-β1-induced HSC-T6. Moreover, overexpression of rno-miR-667-5p significantly reverses the effect of lnc-BIHAA1 on HSC-T6.

Conclusions

BMSC treatment suppresses hepatic fibrosis by downregulating the lnc-BIHAA1/rno-miR-667-5p signaling pathway in HSCs. Our results provide a scientific basis for establishing BMSCs as a biological treatment method for liver fibrosis.

Decursin ameliorates carbon tetrachloride-induced liver fibrosis by facilitating ferroptosis of hepatic stellate cells

Decursin possesses the potential to alleviate transforming growth factor (TGF)-β-induced hepatic stellate cells (HSCs) activation. However, the mechanisms by which decursin alleviates hepatic fibrosis remain not fully understood. Our aim is to explore the function of decursin on regulating HSCs activation and hepatic fibrosis. The anti-fibrotic effect of decursin was evaluated by Masson and Sirius red staining, and immunohistochemical (IHC) and quantitative real-time PCR (qRT-PCR) analysis for alpha-smooth muscle actin (α-SMA) and collagen types I (Col1a1) expression. Ferroptosis was assessed by measuring iron concentration, glutathione peroxidase 4 (Gpx4) and Prostaglandin endoperoxide synthase 2 (Ptgs2) expression, glutathione (GSH) level, lipid peroxidation, and reactive oxygen species (ROS) level. We found that decursin treatment decreased CCl4-induced liver fibrosis. The primary HSCs isolated from decursin-treated group showed an increased Fe2+, lipid ROS level, and decreased Gpx4 and GSH levels compared with HSCs from model group. Moreover, decursin promoted ferroptosis in activated HSCs in vitro, as evidenced by declined Gpx4 and GSH levels, increased Fe2+, ROS, and Ptgs2 levels compared with control. More important, ferroptosis inhibitor destroyed the anti-fibrosis effect of decursin on HSCs. In summary, these data suggest that decursin has potential to treat hepatic fibrosis.

MicroRNA-15a inhibits hepatic stellate cell activation and proliferation via targeting SRY-box transcription factor 9

Accumulating research have indicated that microRNAs are associated with the progression of hepatic fibrosis (HF). Nevertheless, the biological role and function of microRNA (miR)-15a in HF are still unknown. Our data revealed that miR-15a expression was decreased in TGF-β1-treated LX-2 cells and CCl₄-induced mouse model. Additionally, miR-15a could directly target the 3’‑untranslated region of SRY-box transcription factor 9 (SOX9) to inhibit its expression. miR-15a overexpression attenuated the viability and invasion, but enhanced apoptosis in LX-2 cells. However, miR-15a knockdown had the opposite effects. Interestingly, SOX9 overexpression reversed the changes in cell viability, invasion and apoptosis mediated by miR-15a overexpression. Moreover, the miR-15a overexpression-mediated collagen I and alpha smooth muscle actin (a-SMA) downregulation were reversed by SOX9 overexpression. Overall, miR-15a could inhibit LX-2 cell viability and HF pathogenesis by targeting SOX9 in vitro and in vivo.

Multifunctional regulatory protein connective tissue growth factor (CTGF): A potential therapeutic target for diverse diseases

Connective tissue growth factor (CTGF), a multifunctional protein of the CCN family, regulates cell proliferation, differentiation, adhesion, and a variety of other biological processes. It is involved in the disease-related pathways such as the Hippo pathway, p53 and nuclear factor kappa-B (NF-κB) pathways and thus contributes to the developments of inflammation, fibrosis, cancer and other diseases as a downstream effector. Therefore, CTGF might be a potential therapeutic target for treating various diseases. In recent years, the research on the potential of CTGF in the treatment of diseases has also been paid more attention. Several drugs targeting CTGF (monoclonal antibodies FG3149 and FG3019) are being assessed by clinical or preclinical trials and have shown promising outcomes. In this review, the cellular events regulated by CTGF, and the relationships between CTGF and pathogenesis of diseases are systematically summarized. In addition, we highlight the current researches, focusing on the preclinical and clinical trials concerned with CTGF as the therapeutic target.

Fibrosis Is a Basement Membrane-Related Disease in the Cornea: Injury and Defective Regeneration of Basement Membranes May Underlie Fibrosis in Other Organs

Every organ develops fibrosis that compromises functions in response to infections, injuries, or diseases. The cornea is a relatively simple, avascular organ that offers an exceptional model to better understand the pathophysiology of the fibrosis response. Injury and defective regeneration of the epithelial basement membrane (EBM) or the endothelial Descemet's basement membrane (DBM) triggers the development of myofibroblasts from resident corneal fibroblasts and bone marrow-derived blood borne fibrocytes due to the increased entry of TGF beta-1/-2 into the stroma from the epithelium and tears or residual corneal endothelium and aqueous humor. The myofibroblasts, and disordered extracellular matrix these cells produce, persist until the source of injury is removed, the EBM and/or DBM are regenerated, or replaced surgically, resulting in decreased stromal TGF beta requisite for myofibroblast survival. A similar BM injury-related pathophysiology can underly the development of fibrosis in other organs such as skin and lung. The normal liver does not contain traditional BMs but develops sinusoidal endothelial BMs in many fibrotic diseases and models. However, normal hepatic stellate cells produce collagen type IV and perlecan that can modulate TGF beta localization and cognate receptor binding in the space of Dissé. BM-related fibrosis is deserving of more investigation in all organs.

Ubiquitin specific peptidase 1 promotes hepatic fibrosis through positive regulation of CXCL1 by deubiquitinating SNAIL

BACKGROUND

Hepatic fibrosis is attributed to an imbalance of extracellular matrix production and lysis. Human hepatic stellate cells (HSCs) have been uncovered to converge through complex interactions with hepatocytes and immune cells, causing scarring in liver damage.

AIMS

We aimed to investigate the expression status of ubiquitin specific peptidase 1 (USP1) and its potential mechanisms on HSCs and hepatic fibrosis.

METHODS

Hepatic fibrosis animal and cell models were generated using mice with carbon tetrachloride (CCl4) treatment and HSCs LX-2 with TGF-β1 treatment. Relationships among USP1, SNAIL, and CXCL1 were identified via dual-luciferase reporter gene assay, co-immunoprecipitation, and chromatin immunoprecipitation. With gain- and loss-of-experiments, CCK-8 and flow cytometry assays were employed for cell proliferation and apoptosis.

RESULTS

USP1 upregulated SNAIL expression through deubiquitination to increase CXCL1 expression. USP1 downregulation decreased expressions of fibrosis-related genes, suppressed proliferation, and promoted apoptosis in TGF-β1-induced LX-2 cells, which were reversed by SNAIL overexpression. The pro-fibrosis role caused by SNAIL upregulation was abolished by CXCL1 reduction. Promotive function of USP1/SNAIL/CXCL1 axis in hepatic fibrosis was further confirmed in vivo.

CONCLUSION

These data supported siRNA-mediated silencing of USP1 improved hepatic fibrosis through inhibition of SNAIL and CXCL1, which yields a new therapeutic target for hepatic fibrosis treatment.

Interleukin 10 inhibits oxidative stress-induced autophagosome formation in hepatic stellate cells by activating the mTOR-STAT3 pathway

Autophagy is involved in the activation of hepatic stellate cells (HSCs) and liver fibrosis. Previous studies have shown that interleukin 10 (IL-10) has a marked therapeutic effect against liver fibrosis. However, few studies have evaluated the effect of IL-10 on autophagy in HSCs and fibrotic livers. The aim of this study was to assess the effect of IL-10 on the autophagy of HSCs in vitro and in vivo and then to explore the underlying pathway. In vitro, The results revealed that IL-10 had inhibitory effects on hydrogen peroxide (H₂O₂)-induced autophagy, as evidenced by the decreased LC3II/I ratio and Beclin1 expression, increased p62 expression, reduced numbers of autophagosomes, and blocked autophagy initiation in HSCs. Mechanistically, IL-10 significantly promoted the phosphorylation of the signal transducer and activator of transcription 3(STAT3) and mammalian target of rapamycin (mTOR), leading to the activation of STAT3 and mTOR, which in turn inhibited autophagy. In vivo, the increased expression of IL-10 in fibrotic livers inhibited significantly liver fibrosis and decreased the autophagic activity in fibrotic livers and HSCs. Overall, our results indicate that IL-10 suppressed H₂O₂-induced autophagy in HSCs by activating the STAT3-mTOR signaling pathway. Present study provides a new theoretical basis for the anti-fibrotic effects of IL-10.

Curdione and Schisandrin C Synergistically Reverse Hepatic Fibrosis via Modulating the TGF-β Pathway and Inhibiting Oxidative Stress

Hepatic fibrosis is the final pathway of several chronic liver diseases, which is characterized by the accumulation of extracellular matrix due to chronic hepatocyte damage. Activation of hepatic stellate cells and oxidative stress (OS) play an important role in mediating liver damage and initiating hepatic fibrosis. Hence, hepatic fibrosis can be reversed by inhibiting multiple channels such as oxidative stress, liver cell damage, or activation of hepatic stellate cells. Liuwei Wuling Tablets is a traditional Chinese medicine formula with the effect of anti- hepatic fibrosis, but the composition and mechanism of reversing hepatic fibrosis are still unclear. Our study demonstrated that one of the main active components of the Chinese medicine Schisandra chinensis, schisandrin C (Sin C), significantly inhibited oxidative stress and prevented hepatocyte injury. Meanwhile one of the main active components of the Chinese medicine Curdione inhibited hepatic stellate cell activation by targeting the TGF-β1/Smads signaling pathway. The further in vivo experiments showed that Sin C, Curdione and the combination of both have the effect of reversing liver fibrosis in mice, and the combined effect of inhibiting hepatic fibrosis is superior to treatment with Sin C or Curdione alone. Our study provides a potential candidate for multi-molecular or multi-pathway combination therapies for the treatment of hepatic fibrosis and demonstrates that combined pharmacotherapy holds great promise in the prevention and treatment of hepatic fibrosis.

LncRNA MEG3 reverses CCl4-induced liver fibrosis by targeting NLRC5

Liver fibrosis is a persistent pathological repair of chronic liver injury, which is characterized by excessive deposition of collagen-dominated extracellular matrix (ECM). It is well known that hepatic fibrosis can be reversed in the absence of etiology. Studies have shown that long non-coding RNA (Lnc RNA) maternally expressed gene3 (MEG3) has strong effects on the activation of hepatic stellata cells (HSCs). However, the function of MEG3 in the reversal of liver fibrosis has not been studied. In this experiment, we studied the content expression, function, and part of the potential mechanism of MEG3 in reversing liver fibrosis. In in vivo and in vitro models, we found that MEG3 was down-regulated during the formation of liver fibrosis, while it was up-regulated during the reversal of liver fibrosis. Then, it was found that the silencing of MEG3 could gradually restore the activity of the inactivated LX-2 cells, Overexpression of MEG3 can inhibit the activation of LX-2 cells, accelerate the reversal of liver fibrosis. Through catRAPID analysis, it was found that NLR family CARD domain containing 5 (NLRC5) may be a target of MEG3. We found that, after MEG3 silencing, NLRC5 expression was upregulated in LX-2 cells in the reverse phase, while, after MEG3 overexpression, NLRC5 expression was decreased. Further, we verified that MEG3 can target NLRC5 through RNA pull down experiment. Therefore, MEG3 may inhibit the activation of hepatic stellate cells by targeting NLRC5, thus accelerating the reversal of hepatic fibrosis.

Hepatic Stellate Cell: A Double-Edged Sword in the Liver

Hepatic stellate cells (HSCs) are located in the space of Disse, between liver sinusoidal endothelia cells (LSECs) and hepatocytes. They have surprised and excited hepatologists for their biological characteristics. Under physiological quiescent conditions, HSCs are the major vitamin A-storing cells of the liver, playing crucial roles in the liver development, regeneration, and tissue homeostasis. Upon injury-induced activation, HSCs convert to a pro-fibrotic state, producing the excessive extracellular matrix (ECM) and promoting angiogenesis in the liver fibrogenesis. Activated HSCs significantly contribute to liver fibrosis progression and inactivated HSCs are key to liver fibrosis regression. In this review, we summarize the comprehensive understanding of HSCs features, including their roles in normal liver and liver fibrosis in hopes of advancing the development of emerging diagnosis and treatment for hepatic fibrosis.

Cellular and Molecular Mechanisms Underlying Liver Fibrosis Regression

Chronic liver injury of different etiologies may result in hepatic fibrosis, a scar formation process consisting in altered deposition of extracellular matrix. Progression of fibrosis can lead to impaired liver architecture and function, resulting in cirrhosis and organ failure. Although fibrosis was previous thought to be an irreversible process, recent evidence convincingly demonstrated resolution of fibrosis in different organs when the cause of injury is removed. In the liver, due to its high regenerative ability, the extent of fibrosis regression and reversion to normal architecture is higher than in other tissues, even in advanced disease. The mechanisms of liver fibrosis resolution can be recapitulated in the following main points: removal of injurious factors causing chronic hepatic damage, elimination, or inactivation of myofibroblasts (through various cell fates, including apoptosis, senescence, and reprogramming), inactivation of inflammatory response and induction of anti-inflammatory/restorative pathways, and degradation of extracellular matrix. In this review, we will discuss the major cellular and molecular mechanisms underlying the regression of fibrosis/cirrhosis and the potential therapeutic approaches aimed at reversing the fibrogenic process.

Epoxyeicosatrienoic Acids and Fibrosis: Recent Insights for the Novel Therapeutic Strategies

Organ fibrosis often ends in eventual organ failure and leads to high mortality. Although researchers have identified many effector cells and molecular pathways, there are few effective therapies for fibrosis to date and the underlying mechanism needs to be examined and defined further. Epoxyeicosatrienoic acids (EETs) are endogenous lipid metabolites of arachidonic acid (ARA) synthesized by cytochrome P450 (CYP) epoxygenases. EETs are rapidly metabolized primarily via the soluble epoxide hydrolase (sEH) pathway. The sEH pathway produces dihydroxyeicosatrienoic acids (DHETs), which have lower activity. Stabilized or increased EETs levels exert several protective effects, including pro-angiogenesis, anti-inflammation, anti-apoptosis, and anti-senescence. Currently, intensive investigations are being carried out on their anti-fibrotic effects in the kidney, heart, lung, and liver. The present review provides an update on how the stabilized or increased production of EETs is a reasonable theoretical basis for fibrosis treatment.

CircRNAs: Decrypting the novel targets of fibrosis and aging

Fibrosis is a typical aging-related pathological process involving almost all organs. It is usually initiated by organic injury and leads to the gradual decline of organ function or even loss. Circular RNAs (circRNAs) are being hailed as a newly rediscovered class of covalently closed transcripts without a 5' cap or 3' tail which draw increasing attention. In particular, circRNAs have been identified to be involved in the multifaceted processes of fibrosis in various organs, including the heart, liver, lung, and kidney. As more and more circRNAs are functionally characterized, they have become novel therapies for fibrosis. In this review, we systematically summarized current studies regarding the roles of circRNAs in fibrosis and shed light on the basis of circRNAs as a potential treatment for fibrosis.

Antifibrotic Effects of Kangxian Ruangan Capsule on Rats with Nonalcoholic Fatty Liver Fibrosis and Hepatic Stellate Cells through Regulation of TGF-β and TLR4 Signaling Pathways

Kangxian ruangan (KXRG) is a traditional Chinese medicine (TCM) formula consisting of 12 herbs. TCM syndrome differentiation proposes that KXRG exerts pharmacological effects against nonalcoholic fatty liver disease (NAFLD) fibrosis. This work investigates the effect of KXRG on NAFLD fibrosis in vivo and in vitro. In vivo, the NAFLD fibrosis model was constructed in Wistar rats using methionine- and choline-deficient (MCD) diet, followed by KXRG (0.92 g/kg/d) treatment for 8 weeks. In vitro, primary hepatic stellate cells (HSCs) were activated using platelet-derived growth factor (PDGF) and treated with KXRG. Molecular mechanisms underlying fibrosis were investigated. After 8 weeks, compared with the control groups, the histological lesions, degree of fibrosis, and inflammatory reaction increased with the MCD diet as demonstrated by histological changes and increased fibrosis-related (α-SMA, TGF-β, COL1A1, and desmin, P < 0.01) and inflammation-related factors (TNF-α, MCP-1, and F4/80, P < 0.01), whereas they decreased with KXRG treatment (P < 0.01). KXRG not only inhibited the proliferation of activated HSCs and promoted their apoptosis but also resulted in G0-G1 arrest. Furthermore, KXRG suppressed HSC activation (P < 0.01), collagen synthesis (P < 0.01), and α-SMA expression (P < 0.01) with PDGF stimulation. In both the MCD diet-induced animal model and PDGF-induced cell model, KXRG inhibited TGF-β and TLR4 signaling (P < 0.01), similar to corresponding small-molecule inhibitors. These results demonstrated that KXRG might exert suppressive effects against NAFLD fibrosis via regulating TGF-β and TLR4 signaling. KXRG may act as a natural and potent therapeutic agent against NAFLD.

Hepatic Stellate Cell: A Potential Target for Hepatocellular Carcinoma

Liver cancer is a leading cause of cancer-related death worldwide, in which hepatocellular carcinoma (HCC) accounts for the majority. Despite the progression in treatment, the prognosis remains extremely poor for HCC patients. The mechanisms of hepatocarcinogenesis are complex, of which fibrosis is acknowledged as the pre-cancerous stage of HCC. Approximately, 80-90% of HCC develops in the fibrotic or cirrhotic livers. Hepatic stellate cells (HSCs), the main effector cells of liver fibrosis, could secret various biological contents to maintain the liver inflammation. By decades, HSCs are increasingly correlated with HCC in the tumor microenvironment. In this review, we summarized the underlying mechanisms that HSCs participated in the genesis and progression of HCC. HSCs secrete various bioactive contents and regulate tumor-related pathways, subsequently contribute to metastasis, angiogenesis, immunosuppression, chemoresistance and cancer stemness. The study indicates that HSC plays vital roles in HCC progression, suggesting it as a promising therapeutic target for HCC treatment.

The bright side of fibroblasts: molecular signature and regenerative cues in major organs

Fibrosis is a pathologic process characterized by the replacement of parenchymal tissue by large amounts of extracellular matrix, which may lead to organ dysfunction and even death. Fibroblasts are classically associated to fibrosis and tissue repair, and seldom to regeneration. However, accumulating evidence supports a pro-regenerative role of fibroblasts in different organs. While some organs rely on fibroblasts for maintaining stem cell niches, others depend on fibroblast activity, particularly on secreted molecules that promote cell adhesion, migration, and proliferation, to guide the regenerative process. Herein we provide an up-to-date overview of fibroblast-derived regenerative signaling across different organs and discuss how this capacity may become compromised with aging. We further introduce a new paradigm for regenerative therapies based on reverting adult fibroblasts to a fetal/neonatal-like phenotype.

Molecular factors associated with regression of liver fibrosis of alcoholic etiology

Liver fibrosis develops as a result of chronic liver damage of various etiologies, is characterized by excessive synthesis of connective tissue by activated stellate liver cells. The toxic effect of alcohol is one of the most significant and common etiological factors worldwide. Stellate cell activation results from the interaction of multiple molecular fibrogenic pathways triggered by intracellular and extracellular, hepatic and extrahepatic stimuli. Data analysis showed that knowledge about these abnormal pathways and biomolecular processes may further contribute to the improvement of approaches to assessment of disease prognosis and treatment of alcoholic liver disease.

Integrating Network Pharmacology and Experimental Validation to Investigate the Effects and Mechanism of Astragalus Flavonoids Against Hepatic Fibrosis

Hepatic fibrosis (HF) represents the excessive wound healing where an excess amount of connective tissues is formed within the liver, finally resulting in cirrhosis or even hepatocellular carcinoma (HCC). Therefore, it is significant to discover the efficient agents and components to treat HF, thus restraining the further progression of hepatopathy. Astragalus membranaceus (Fisch.) Bunge [also called Astragali Radix (AR)] is a famous herb in traditional Chinese medicine (TCM), which possesses a variety of biological activities and exerts good therapeutic effects in the treatment of HF. Flavonoids account for the major active ingredients related to the AR pharmacological effects. Total AR flavonoids have been proved to exert inhibitory effects on hepatic fibrosis. This study aimed to further undertake network pharmacology analysis coupled with experimental validation and molecular docking to investigate the effects and mechanism of multiple flavonoid components from AR against liver fibrosis. The results of the network pharmacology analysis showed that the flavonoids from AR exerted their pharmacological effects against liver fibrosis by modulating multiple targets and pathways. The experimental validation data showed that the flavonoids from AR were able to suppress transforming growth factor beta 1 (TGF-β1)-mediated activation of hepatic stellate cells (HSCs) and reduce extracellular matrix deposition in HSC-T6 cells via regulating the nuclear factor kappa B (NF-κB) signal transduction pathway. The results of the molecular docking study further showed that the flavonoids had a strong binding affinity for IκB kinase (IKKβ) after docking into the crystal structure. The above results indicated that, flavonoids possibly exerted the anti-inflammatory effect on treating HF by mediating inflammatory signaling pathways. The potential mechanism of these flavonoids against liver fibrosis may be related to suppression of the NF-κB pathway through effective inhibition of IKKβ. This study not only provides a scientific basis for clarifying the effects and mechanism of AR flavonoids against liver fibrosis but also suggests a novel promising therapeutic strategy for the treatment of liver fibrosis.

CaMK II/Ca2+ dependent endoplasmic reticulum stress mediates apoptosis of hepatic stellate cells stimulated by transforming growth factor beta 1

Previous studies by our group have demonstrated that the calcium imbalance in rat hepatic stellate cells (HSCs) can induce endoplasmic reticulum stress (ERS) and promote cell apoptosis. KN-62, an inhibitor of Calmodulin kinase II (CaMK II), can decrease the expression of CaMK II that plays a major role in regulating the steady state of intracellular Ca2+. Uridine triphosphate (UTP) plays a biological role in increasing indirectly the level of intracellular Ca2+. In the experiment, we demonstrate that KN-62 and UTP can inhibit the proliferation and promote the apoptosis in HSCs, increase the level of intracellular Ca2+ and the expression of ERS protein GRP78, and increase the apoptosis protein Caspase-12 and Bax expression, while decrease the expression of Bcl-2 protein. Our findings indicate that the CaMK II/Ca2+ signaling pathway regulates the ERS apoptosis pathway and induces HSC apoptosis.

Hepatic stellate cells specific liposomes with the Toll-like receptor 4 shRNA attenuates liver fibrosis

The hepatic stellate cells (HSCs) play a significant role in the onset of liver fibrosis, which can be treated by the inhibition and reversal of HSC activation. The RNA interference-mediated TLR4 gene silencing might be a potential therapeutic approach for liver fibrosis. The crucial challenge in this method is the absence of an efficient delivery system for the RNAi introduction in the target cells. HSCs have an enhanced capacity of vitamin A intake as they contain retinoic acid receptors (RARs). In the current study, we developed cationic liposomes modified with vitamin A to improve the specificity of delivery vehicles for HSCs. The outcome of this study revealed that the VitA-coupled cationic liposomes delivered the TLR4 shRNA to aHSCs more efficiently, as compared to the uncoupled cationic liposomes, both in the in vitro and in vivo conditions. Besides, as evident from the outcome of this study, the TLR4 gene silencing inhibited the HSCs activation and attenuated the liver fibrosis via the NF-κB transcriptional inactivation, pro-inflammatory cytokines secretion and reactive oxygen species (ROS) synthesis. Thus, the VitA-coupled liposomes encapsulated with the TLR4-shRNA might prove as an efficient therapeutic agent for liver fibrosis.

Peroxisome proliferator-activated receptors in the pathogenesis and therapies of liver fibrosis

Liver fibrosis is a dynamic wound-healing process associated with the deposition of extracellular matrix produced by myofibroblasts. HSCs activation, inflammation, oxidative stress, steatosis and aging play critical roles in the progression of liver fibrosis, which is correlated with the regulation of the peroxisome proliferator-activated receptor (PPAR) pathway. As nuclear receptors, PPARs reduce inflammatory response, regulate lipid metabolism, and inhibit fibrogenesis in the liver associated with aging. Thus, PPAR ligands have been investigated as possible therapeutic agents. Mounting evidence indicated that some PPAR agonists could reverse steatohepatitis and liver fibrosis. Consequently, targeting PPARs might be a promising and novel therapeutic option against liver fibrosis. This review summarizes recent studies on the role of PPARs on the pathogenesis and treatment of liver fibrosis.

Extracellular vesicles: Natural liver-accumulating drug delivery vehicles for the treatment of liver diseases

Extracellular vesicles (EVs) are excellent potential vectors for the delivery of therapeutic drugs. However, issues with biological safety and disease targeting substantially limit their clinical application. EVs from red blood cells (RBC-EVs) are potential drug delivery vehicles because of their unique biological safety. Here, we demonstrated that EVs, including RBC-EVs, show natural liver accumulation. Mechanistically, the liver environment induces macrophages to phagocytize RBC-EVs in a C1q-dependent manner. RBC-EVs loaded with antisense oligonucleotides of microRNA-155 showed macrophage-dependent protective effects against acute liver failure (ALF) in a mouse model. These RBC-EVs were also effective in treatment of ALF. Furthermore, compared to routine doses of doxorubicin and sorafenib (SRF), RBC-EVs loaded with doxorubicin or SRF showed enhanced therapeutic effects on a murine model of orthotopic liver cancer through a mechanism dependent on macrophages. Importantly, drug-loaded RBC-EVs showed no systemic toxicity at therapeutically effective doses, whereas routine doses of doxorubicin and SRF showed obvious toxicity. Thus, drug-loaded RBC-EVs hold high potential for clinical applications in the treatment of liver disease therapy.

Microfluidic organ-on-a-chip models of human liver tissue

The liver is the largest internal organ of the body with complex microarchitecture and function that plays critical roles in drug metabolism. Hepatotoxicity and drug-induced liver injury (DILI) caused by various drugs is the main reason for late-stage drug failures. Moreover, liver diseases are among the leading causes of death in the world, with the number of new cases arising each year. Although animal models have been used to understand human drug metabolism and toxicity before clinical trials, tridimensional microphysiological systems, such as liver-on-a-chip (Liver Chip) platforms, could better recapitulate features of human liver physiology and pathophysiology and thus, are often more predictive of human outcome. Liver Chip devices have shown promising results in mimicking in vivo condition by recapitulating the sinusoidal structure of the liver, maintaining high cell viability and cellular phenotypes, and emulating native liver functions. Here, we first review the cellular constituents and physiology of the liver and then critically discuss the state-of-the-art chip-based liver models and their applications in drug screening, disease modeling, and regenerative medicine. We finally address the pending issues of existing platforms and touch upon future directions for developing new, advanced on-chip models.

Abscisic acid ameliorates oxidative stress, inflammation, and apoptosis in thioacetamide-induced hepatic fibrosis by regulating the NF-кB signaling pathway in mice

The purpose of this study was to determine whether abscisic acid (ABA) can protect against liver fibrosis induced by thioacetamide (TAA) in vivo by inhibiting apoptosis and inflammatory responses. To this end, three times per week, mice were injected intraperitoneally with TAA (200 mg/kg) for 8 weeks to induce liver fibrosis. After the fourth week of treatment, histological changes, the serum biochemical index, inflammation, and hepatocyte apoptosis factors (e.g., caspase-3, B-cell lymphoma 2 [Bcl-2], Bcl-2-associated X [Bax]) were detected to clarify its underlying mechanism. The results clearly indicated that ABA improves TAA-induced hepatic injury and collagen accumulation in mice. Otherwise, ABA significantly reduced liver fibrosis by regulating caspase-3 and Bcl-2, α-smooth muscle actin, and collagen I. ABA inhibited the nuclear factor kappa B pathway, significantly alleviating oxidative stress and inflammatory cytokines. Therefore, ABA may be a potential therapeutic agent for preventing liver damage.

Glutamate-Cysteine Ligase Catalytic Subunit Attenuated Hepatitis C Virus-Related Liver Fibrosis and Suppressed Endoplasmic Reticulum Stress

The study aimed to clarify the role and molecular mechanism of glutamate-cysteine ligase catalytic subunit (GCLC) in modulating Hepatitis C virus (HCV)-related liver fibrosis. Twenty patients with HCV-related liver fibrosis and 15 healthy controls were enrolled. Differentially expressed plasma mRNAs were detected by digital gene expression profile analysis and validated by qRT-PCR. Hepatic histopathology was observed by H&E and Masson stained liver sections. The mRNA and protein expression of GCLC, endoplasmic reticulum (ER) stress markers, and inflammatory and fibrogenic factors were detected in liver tissues from patients with HCV-related hepatic fibrosis and HCV core protein-expressing LX-2. The GCLC-overexpressing LX-2 were established by transfecting puc19-GCLC plasmid. Then, glutathione and reactive oxygen species (ROS) levels were measured respectively by spectrophotometric diagnostic kit and dihydrodichlorofluorescein diacetate kit. GCLC were dramatically down-regulated in HCV-related fibrotic livers and activated HSCs, which companied with up-regulation of ER stress-related genes, including inositol-requiring 1 (IRE1) and glucose-regulated protein 78 (GRP78). Also, the proinflammatory and profibrogenic gene, including nuclear factor kappa B (NF-κB), tumor necrosis factor α (TNFα), and transforming growth factor 1(TGFβ1), was highly upregulated. Overexpression of GCLC in hepatic stellate cells could suppress α-SMA and collagen I expression, produce hepatic GSH and reduce ROS, and down-regulate IRE1, GRP78, NF-κB, TNF-α, and TGFβ1 expression. GCLC was a negative regulatory factor in the development of HCV-related liver fibrosis and might be a potential therapeutic target for liver fibrosis.

Human amniotic stem cells improve hepatic microvascular dysfunction and portal hypertension in cirrhotic rats

BACKGROUND AND AIMS

Portal hypertension is the main consequence of cirrhosis, responsible for the complications defining clinical decompensation. The only cure for decompensated cirrhosis is liver transplantation, but it is a limited resource and opens the possibility of regenerative therapy. We investigated the potential of primary human amniotic membrane-derived mesenchymal stromal (hAMSCs) and epithelial (hAECs) stem cells for the treatment of portal hypertension and decompensated cirrhosis.

METHODS

In vitro: Primary liver sinusoidal endothelial cells (LSECs) and hepatic stellate cells (HSCs) from cirrhotic rats (chronic CCl₄ inhalation) were co-cultured with hAMSCs, hAECs or vehicle for 24 hours, and their RNA profile was analysed. In vivo: CCl₄-cirrhotic rats received 4x10⁶ hAMSCs, 4x10⁶ hAECs, or vehicle (NaCl 0.9%) (intraperitoneal). At 2-weeks we analysed: a) portal pressure (PP) and hepatic microvascular function; b) LSECs and HSCs phenotype; c) hepatic fibrosis and inflammation.

RESULTS

In vitro experiments revealed sinusoidal cell phenotype amelioration when co-cultured with stem cells. Cirrhotic rats receiving stem cells, particularly hAMSCs, had significantly lower PP than vehicle-treated animals, together with improved liver microcirculatory function. This hemodynamic amelioration was associated with improvement in LSECs capillarization and HSCs de-activation, though hepatic collagen was not reduced. Rats that received amnion derived stem cells had markedly reduced hepatic inflammation and oxidative stress. Finally, liver function tests significantly improved in rats receiving hAMSCs.

CONCLUSIONS

This preclinical study shows that infusion of human amniotic stem cells effectively decreases PP by ameliorating liver microcirculation, suggesting that it may represent a new treatment option for advanced cirrhosis with portal hypertension.

BAY 41-2272 Attenuates CTGF Expression via sGC/cGMP-Independent Pathway in TGFβ1-Activated Hepatic Stellate Cells

Activation of hepatic stellate cells (HSCs) is a critical pathogenic feature of liver fibrosis and cirrhosis. BAY 41-2272 is a canonical non-nitric oxide (NO)-based soluble guanylyl cyclase (sGC) stimulator that triggers cyclic guanosine monophosphate (cGMP) signaling for attenuation of fibrotic disorders; however, the impact of BAY 41-2272 on HSC activation remains ill-defined. Transforming growth factor (TGF)β and its downstream connective tissue growth factor (CTGF or cellular communication network factor 2, CCN2) are critical fibrogenic cytokines for accelerating HSC activation. Here, we identified that BAY 41-2272 significantly inhibited the TGFβ1-induced mRNA and protein expression of CTGF in mouse primary HSCs. Indeed, BAY 41-2272 increased the sGC activity and cGMP levels that were potentiated by two NO donors and inhibited by a specific sGC inhibitor, ODQ. Surprisingly, the inhibitory effects of BAY 41-2272 on CTGF expression were independent of the sGC/cGMP pathway in TGFβ1-activated primary HSCs. BAY 41-2272 selectively restricted the TGFβ1-induced phosphorylation of Akt but not canonical Smad2/3 in primary HSCs. Together, we illustrate a unique framework of BAY 41-2272 for inhibiting TGFβ1-induced CTGF upregulation and HSC activation via a noncanonical Akt-dependent but sGC/cGMP-independent pathway.

Proteomic profiling of hepatic stellate cells in alcohol liver fibrosis reveals proteins involved in collagen production

BACKGROUND

Hepatic stellate cell (HSC) activation has central functions in alcohol-induced liver fibrosis. Proteins of HSCs in alcoholic liver fibrosis (ALF) are still not completely understood. Here, we performed a proteomic study to discover proteins related to ALF using HSCs isolated from a rat model.

METHODS

Sprague-Dawley rats were fed with ethanol for 2 or 6 weeks. Liver histology was assessed using Sirius red and Oil red O staining. HSCs were enriched by using Percoll density gradient centrifugation, and analyzed using flow cytometry. Proteins extracted from HSCs were separated using two-dimensional electrophoresis (2DE). Differentially expressed proteins were identified using liquid chromatography-mass spectrometry (LC-MS). The characteristics of the differentially expressed proteins were analyzed using the UniProtKB database and STRING software. The mRNA levels of two differentially expressed proteins were analyzed using real-time RT-PCR, of which NADH dehydrogenase (ubiquinone) flavoprotein 2, mitochondrial (Ndufv2) was further investigated using Western blot (WB) and immunohistochemical analysis in the ALF model and human liver tissues. The relationship between Ndufv2 and alcohol stimulation was evaluated using WB. Next, Ndufv2 was knocked-down by shRNA in the HSC-T6 cell line. Three genes (encoding collagen, metalloproteinase inhibitor 1 [TIMP-1], and α-smooth muscle actin [a-SMA]) related to HSC activation were detected.

RESULTS

An ALF model was successfully established, with a liver fibrosis score of 1-2 (S1-2), and some big fat vacuoles development. Twenty-one non-abundant proteins with more than a 2-fold difference were identified using mass spectrometry, including 7 upregulated and 14 downregulated proteins. These differential proteins are a response to antigen presentation, mitochondrial metabolism, ethanol, and collagen degradation. Among them, two upregulated proteins (Ndufv2 and ATP synthase subunit alpha, mitochondrial [ATP5a1]) were involved in mitochondrial metabolism in ALF, and showed concurrent changes in mRNA and protein levels. Ndufv2 was upregulated in HSCs, as shown by WB, in non-parenchymal cells (NPCs) in the rat model and human liver tissues, and detected using immunohistochemistry. Ndufv2 was also upregulated after alcohol stimulation. Following Ndufv2 knockdown, collagen, TIMP-1, and α-SMA were downregulated compared with that in the controls.

CONCLUSIONS

A proteomic study was performed to discover proteins related to ALF in HSCs isolated from a rat model. Twenty-one differentially expressed proteins were identified, including proteins involved in mitochondrial metabolism and antigen presentation. Ndufv2, an upregulated protein in ALF, might be involved in ALF through regulating the production of fibrosis factors.

miR-29a-3p suppresses hepatic fibrosis pathogenesis by modulating hepatic stellate cell proliferation via targeting PIK3R3 gene expression

OBJECTIVE

Hepatic stellate cells (HSC) activation and proliferation mediated the pathogenic development of hepatic fibrosis (HF). However, the underlying mechanisms remain poorly understood. In this study, we aimed to investigate the miR-29a-3p and its effects on PIK3R3 expression in HF pathogenesis.

METHODS

LX-2 cells treated with TGF-β1 was used as the in vitro HF model. The expression of microRNAs and proteins in LX-2 cells were detected by quantitative RT-PCR and western blotting. Then, miR-29a-3p expression in LX-2 cells were altered via transfection with specific mimics or inhibitors, followed by cell proliferation measured through CCK-8, Edu staining and colony formation. The dual luciferase reporter assay was done to assess binding of miR-29a-3p with PIK3R3 gene sequences. Moreover, PIK3R3 gene overexpression in LX-2 cell was realized through transfection with recombinant pcDNA3.0-PIK3R3 plasmids.

RESULTS

Successful establishment of cellular HF model was validated through the increased Col-I and a-SMA expression in TGF-β1-treated LX-2 cells shown by qRT-PCR and Western blot. In such model, miR-29a-3p expression in LX-2 cells showed the greatest decrease among four candidate microRNAs in response to TGF-β1 treatment. Also, miR-29a-3p directly binds with the 3' UTR region of the PIK3R3 gene to suppress its expression in LX-2 cells. Furthermore, PIK3R3 gene overexpression effectively abrogated the changes of LX-2 cell proliferation, AKT phosphorylation and Col-I and a-SMA expression caused by miR-29a-3p mimics.

CONCLUSION

MiR-29a-3p regulates hepatic stellate cell proliferation and hepatic fibrosis pathogenesis by targeting PIK3R3 expression and modulating the PI-3K/AKT signaling.

Levistilide A reverses rat hepatic fibrosis by suppressing angiotensin II‑induced hepatic stellate cells activation

The renin angiotensin system (RAS) serves an important role in the development of hepatic fibrosis. Therefore, the present study investigated the effect of levistilide A (Lev A) on hepatic fibrosis via regulation of RAS. The effects of Lev A on the proliferation and activation of hepatic stellate cells (HSCs) were measured using a 5-ethynyl-2′-deoxyuridine assay, western blot analysis and immunofluorescence. The in vivo anti-hepatic fibrosis effect of Lev A was examined using a CCL₄-induced rat fibrosis model. Lev A significantly prohibited angiotensin (Ang) II-induced proliferation of HSCs, and overexpression of smooth muscle α-actin (α-SMA) and F-actin in HSCs. Lev A partly reversed Ang II-induced angiotensin type 1 receptor (AT1R) upregulation and ERK and c-Jun phosphorylation. In CCL₄-induced hepatic fibrosis rats, Lev A treatment significantly decreased the expression of collagen, α-SMA and hydroxyproline in rat liver, and improved liver functions. Lev A treatment also significantly inhibited the CCL₄-induced increase in plasma Ang II, and upregulation of AT1R and phosphorylated ERK in rat liver. In conclusion, Lev A is a potential agent for the treatment of hepatic fibrosis by suppressing Ang II/AT1R/ERK/c-Jun activation in HSCs.

Hepatoprotection and hepatotoxicity of Chinese herb Rhubarb (Dahuang): How to properly control the "General (Jiang Jun)" in Chinese medical herb

Chinese herb Rhubarb (Dahuang), one of the most widely used traditional Chinese medicine in clinical application for over a thousand years and known as the "General (Jiang Jun)" in Chinese medical herb, currently used clinically for long-term treatment of gastrointestinal diseases and chronic liver diseases. Through previous researches, it has been identified that Rhubarb possessed a good hepatoprotective effect, which primarily protected liver from oxidation, fibrosis and cirrhosis, liver failure, hepatocellular carcinoma and various types of hepatitis. Meanwhile, it has been recently reported that long-term administration of Rhubarb preparation may undertake the risk of liver damage, which has aroused worldwide doubts about the safety of Rhubarb. Therefore, how to correctly understand the "two-way" effect of Rhubarb on liver protection and liver toxicity provides a basis for scientific evaluation of Rhubarb's efficacy on liver and side effects, as well as guiding clinical rational drug use. In this review, the mechanisms of Rhubarb how to play a role in hepatoprotection and why it causes hepatotoxic potential will be elaborated in detail and critically. In addition, some positive clinical guidances are also advised on how to reduce its hepatotoxicity in medical treatment.