JNK1 induces hedgehog signaling from stellate cells to accelerate liver regeneration in mice

Beta-catenin/sirtuin 1/farnesoid X receptor pathway promotion of portal vein ligation and parenchymal transection-induced rapid liver regeneration

BACKGROUND

By accelerating the regeneration of the future liver remnant, portal vein ligation and parenchymal transection allows for more extensive hepatectomy. Given that the mechanism remains poorly understood, the aim of this study was to investigate the mechanism of portal vein ligation and parenchymal transection-induced liver regeneration.

METHODS

A portal vein ligation and parenchymal transection-induced liver regeneration mouse model was established, followed by RNA microarray analysis to identify candidate molecules. Genomic deletion and chemical manipulation of target molecules were used to explore their functions in portal vein ligation and parenchymal transection-induced liver regeneration. Validation was conducted using a diseased liver model and human samples.

RESULTS

Portal vein ligation and parenchymal transection-induced liver regeneration was significantly accelerated compared with that in sham-operated mice (P < .05). An RNA microarray revealed that Sirtuin 1 is a crucial molecule in the proliferation of the future liver remnant. Regardless of whether Sirtuin 1 is inhibited chemically or through genetic deletion, portal vein ligation and parenchymal transection-induced liver regeneration is distinctly attenuated. Further investigation revealed that Sirtuin 1 promoted portal vein ligation and parenchymal transection-induced liver regeneration via the farnesoid X receptor. In addition, beta-catenin also was found to participate in the process of future liver remnant proliferation. Chemical inhibition of beta-catenin markedly impaired but activation of WNT/beta-catenin mildly enhanced portal vein ligation and parenchymal transection-induced liver regeneration (P < .05). Deletion of Sirtuin 1 blocked the facilitating effect of beta-catenin on portal vein ligation and parenchymal transection-induced liver regeneration. These findings were validated in diseased liver models and patient samples, confirming the correlation between the beta-catenin/Sirtuin 1/farnesoid X receptor pathway and portal vein ligation and parenchymal transection-induced liver regeneration.

CONCLUSION

Activation of the beta-catenin/Sirtuin 1/farnesoid X receptor pathway offers critical mechanistic insights into accelerating portal vein ligation and parenchymal transection-induced liver regeneration. Modulation of beta-catenin/Sirtuin 1/farnesoid X receptor may therefore improve clinical outcomes in patients receiving staged hepatectomy.

Unraveling enhanced liver regeneration in ALPPS: Integrating multi-omics profiling and in vivo CRISPR in mouse models

BACKGROUND

Postoperative liver failure due to insufficient liver cell quantity and function remains a major cause of mortality following surgery. Hence, additional investigation and elucidation are required concerning suitable surgeries for promoting in vivo regeneration.

METHODS

We established the portal vein ligation (PVL) and associated liver partition and portal vein ligation for staged hepatectomy (ALPPS) mouse models to compare their in vivo regeneration capacity. Then, RNA-seq and microRNA-seq were conducted on the livers from both mouse models. Weighted gene co-expression network analysis algorithm was leveraged to identify crucial gene modules. ScRNA-seq analysis was used to understand the distinctions between Signature30high hepatocytes and Signature30low hepatocytes. Moreover, in vivo, validation was performed in fumarylacetoacetate hydrolase knockout mice with gene editing using the CRISPR-cas9 system. A dual luciferase report system was carried out to further identify the regulatory mechanisms.

RESULTS

RNA-seq analysis revealed that ALPPS could better promote cell proliferation compared to the sham and portal vein ligation models. Moreover, a Plk1-related 30-gene signature was identified to predict the cell state. ScRNA-seq analysis confirmed that signature30high hepatocytes had stronger proliferative ability than signature30low hepatocytes. Using microRNA-seq analysis, we identified 53 microRNAs that were time-dependently reduced after ALPPS. Finally, miR-30a-3p might be able to regulate the expression of Plk1, contributing to the liver regeneration of ALPPS.

CONCLUSIONS

ALPPS could successfully promote liver regeneration by activating hepatocytes into a proliferative state. Moreover, a Plk1-related 30-gene signature was identified to predict the cell state of hepatocytes. miR-30a-3p might be able to regulate the expression of Plk1, contributing to the liver regeneration of ALPPS.

Molecular mechanisms in liver repair and regeneration: from physiology to therapeutics

Liver repair and regeneration are crucial physiological responses to hepatic injury and are orchestrated through intricate cellular and molecular networks. This review systematically delineates advancements in the field, emphasizing the essential roles played by diverse liver cell types. Their coordinated actions, supported by complex crosstalk within the liver microenvironment, are pivotal to enhancing regenerative outcomes. Recent molecular investigations have elucidated key signaling pathways involved in liver injury and regeneration. Viewed through the lens of metabolic reprogramming, these pathways highlight how shifts in glucose, lipid, and amino acid metabolism support the cellular functions essential for liver repair and regeneration. An analysis of regenerative variability across pathological states reveals how disease conditions influence these dynamics, guiding the development of novel therapeutic strategies and advanced techniques to enhance liver repair and regeneration. Bridging laboratory findings with practical applications, recent clinical trials highlight the potential of optimizing liver regeneration strategies. These trials offer valuable insights into the effectiveness of novel therapies and underscore significant progress in translational research. In conclusion, this review intricately links molecular insights to therapeutic frontiers, systematically charting the trajectory from fundamental physiological mechanisms to innovative clinical applications in liver repair and regeneration.

Circulating proliferative factors versus portal inflow redistribution: mechanistic insights of ALPPS-derived rapid liver regeneration

Background

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) can induce accelerated regeneration of future liver remnant (FLR) and effectively reduce the occurrence of liver failure due to insufficient FLR after hepatectomy, thereby increasing the probability of radical resection for previously inoperable patients with liver cancer. However, the exact mechanism by which ALPPS accelerates liver regeneration remains elusive.

Methods

A review of the literature was performed utilizing MEDLINE/PubMed and Web of Science databases in March of 2024. The key words "liver regeneration/hypertrophy", "portal vein ligation/embolization", "two-stage hepatectomy", "liver partition/split" and "future liver remnant" in combination with "mechanisms", "hemodynamics", "cytokines", "growth factors" or "collaterals" were searched in the title and/or abstract. The references of relevant articles were reviewed to identify additional eligible publications.

Results

Previously, a widely accepted view is that the primary role of liver splitting in ALPPS stage 1 is to accelerate liver regeneration by promoting proliferative factor release, but increasing evidence in recent years reveal that not the circulating factors, but the portal hemodynamic alternations caused by liver parenchyma transection play a pivotal role in ALPPS-associated rapid liver hypertrophy.

Conclusion

Parenchyma transection-induced portal hemodynamic alternations are the main triggers or driving forces of accelerated liver regeneration following ALPPS. The release of circulating proliferative factors seems to be a secondary response to liver splitting and plays an auxiliary role in this process.

The role of JNK signaling pathway in organ fibrosis

BACKGROUND

Fibrosis is a tissue damage repair response caused by multiple pathogenic factors which could occur in almost every apparatus and leading to the tissue structure damage, physiological abnormality, and even organ failure until death. Up to now, there is still no specific drugs or strategies can effectively block or changeover tissue fibrosis. JNKs, a subset of mitogen-activated protein kinases (MAPK), have been reported that participates in various biological processes, such as genetic expression, DNA damage, and cell activation/proliferation/death pathways. Increasing studies indicated that abnormal regulation of JNK signal pathway has strongly associated with tissue fibrosis.

AIM OF REVIEW

This review designed to sum up the molecular mechanism progresses in the role of JNK signal pathway in organ fibrosis, hoping to provide a novel therapy strategy to tackle tissue fibrosis.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Recent evidence shows that JNK signaling pathway could modulates inflammation, immunoreaction, oxidative stress and Multiple cell biological functions in organ fibrosis. Therefore, targeting the JNK pathway may be a useful strategy in cure fibrosis.

Liver Extracellular Vesicles and Particles Enriched β-Sitosterol Effectively Promote Liver Regeneration in Mice

Background

The liver's regenerative capacity allows it to repair itself after injury. Extracellular vesicles and particles (EVPs) in the liver's interstitial space are crucial for signal transduction, metabolism, and immune regulation. Understanding the role and mechanism of liver-derived EVPs in regeneration is significant, particularly after partial hepatectomy, where the mechanisms remain unclear.

Methods

A 70% hepatectomy model was established in mice, and EVPs were isolated and characterized using electron microscopy, nanocharacterization, and Western blot analysis. Combined metabolomic and transcriptomic analyses revealed β-sitosterol enrichment in EVPs and activation of the Hedgehog signaling pathway during regeneration. The role of β-sitosterol in EVPs on the Hedgehog pathway and its targets were identified using qRT-PCR, Western blot analysis. The regulation of carnitine synthesis by this pathway was determined using a dual luciferase assay. The effect of a β-sitosterol diet on liver regeneration was verified in mice.

Results

After 70% hepatectomy, the liver successfully regenerated without liver failure or death. At 24 hours post-surgery, tissue staining showed transient regeneration-associated steatosis (TRAS), with increased Ki67 positivity at 48 hours. EVPs displayed a spherical lipid bilayer structure with particle sizes of 70-130 nm. CD9, CD63, and CD81 in liver-derived EVPs were confirmed. Transcriptomic and metabolomic analyses showed EVPs supplementation significantly promoted carnitine synthesis and fatty acid oxidation. Tissue staining confirmed accelerated TRAS resolution and enhanced liver regeneration with EVP supplementation. Mass spectrometry identified β-sitosterol in EVPs, which binds to Smo protein, activating the Hedgehog pathway. This led to the nuclear transport of Gli3, stimulating Setd5 transcription and inducing carnitine synthesis, thereby accelerating fatty acid oxidation. Mice with increased β-sitosterol intake showed faster TRAS resolution and liver regeneration compared to controls.

Conclusion

Liver-derived EVPs promote regeneration after partial hepatectomy. β-sitosterol from EVPs accelerates fatty acid oxidation and promotes liver regeneration by activating Hedgehog signaling pathway.

Impact of the extent and location of liver split on future liver remnant hypertrophy after portal vein ligation in a rat model

BACKGROUND

To investigate the role and mechanism of liver parenchyma transection in accelerating the regeneration of future liver remnants in rats with portal vein ligation (PVL).

METHODS

Rats were randomly divided into the PVL group (90% PVL at the caudate lobe, right lobe , left lateral lobe and left median lobe), associating liver partition and portal vein ligation for staged hepatectomy (portal vein ligation with complete liver parenchyma transection [ALPPS]) group (90% PVL with 80 to 90% liver parenchyma transection), PVL + partial liver partition (PLP) group (90% PVL with 30 to 50% liver parenchyma transection), PVL + partition in the ligated lobe (PLL) group (90% PVL with 40 to 60% liver parenchyma transection in the portal vein ligated lobe), PVL + partition in the remnant lobe (PRL) group (90% PVL with 40 to 60% liver parenchyma transection in the remnant lobe), PVL + radiofrequency ablation (RFA) group (90% PVL with splenic ablation) and sham operation (sham) group. The animals were killed at 4 time points of postoperative days 1, 3, 5, and 7. Six rats were killed at each time point, with 24 rats in each group. The weights of the future liver remnant and whole liver were measured. Serum alanine aminotransferase, aspartate aminotransferase, and total bilirubin were analyzed by using an automatic biochemical analyzer. Serum tumor necrosis factor-α, interleukin-6, and hepatocyte growth factor were measured by enzyme-linked immunosorbent assay. The expression of cell proliferating nuclear antigen (Ki67) and phosphorylated histone H3 was detected by immunohistochemistry, and the positive rate was calculated.

RESULTS

The ALPPS group displayed the highest FLR weight to body weight ratio compared with that of the other groups (P < .05), and the partial liver split (PVL + PLP) group also displayed higher remnant weight to body weight ratio than the ectopic liver split (PVL + PLL and PVL + PRL) groups (P < .05). During the first 7 days after surgery the cytokine levels of the ALPPS, PVL + PLP, PVL + PLL and PVL + PRL groups were comparable (P > .05). The PVL + PLP, PVL + PLL, PVL + PRL and PVL + RFA groups showed similar necrotic areas in the portal vein ligated lobe (P > .05). A hemodynamic study revealed that a liver split along the demarcation line could further increase the portal pressure of the FLR and both the split site and completeness were associated with portal hemodynamic alternations and liver hypertrophy. Extrahepatic organ injury (eg, spleen ablation) also has a significant impact on portal hemodynamics and liver regeneration.

CONCLUSION

Complete liver splitting along the demarcation line induced higher portal vein pressure and more rapid FLR hypertrophy than partial or ectopic liver splitting after PVL. The portal hemodynamic alterations after liver split rather than inflammatory cytokine release may be the major cause of ALPPS-induced rapid liver hypertrophy.

Unveiling the power of microenvironment in liver regeneration: an in-depth overview

The liver serves as a vital regulatory hub for various physiological processes, including sugar, protein, and fat metabolism, coagulation regulation, immune system maintenance, hormone inactivation, urea metabolism, and water-electrolyte acid-base balance control. These functions rely on coordinated communication among different liver cell types, particularly within the liver's fundamental hepatic lobular structure. In the early stages of liver development, diverse liver cells differentiate from stem cells in a carefully orchestrated manner. Despite its susceptibility to damage, the liver possesses a remarkable regenerative capacity, with the hepatic lobule serving as a secure environment for cell division and proliferation during liver regeneration. This regenerative process depends on a complex microenvironment, involving liver resident cells, circulating cells, secreted cytokines, extracellular matrix, and biological forces. While hepatocytes proliferate under varying injury conditions, their sources may vary. It is well-established that hepatocytes with regenerative potential are distributed throughout the hepatic lobules. However, a comprehensive spatiotemporal model of liver regeneration remains elusive, despite recent advancements in genomics, lineage tracing, and microscopic imaging. This review summarizes the spatial distribution of cell gene expression within the regenerative microenvironment and its impact on liver regeneration patterns. It offers valuable insights into understanding the complex process of liver regeneration.

In silico and in vivo demonstration of the regulatory mechanism of Qi-Ge decoction in treating NAFLD

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD), a chronic and progressive liver disease, often causes steatosis and steatohepatitis. Qi-Ge decoction (QGD) shows a good effect against NAFLD in the clinic. But the molecular mechanism for QGD in improving NAFLD is unknown.

PURPOSE

This study explored the molecular mechanism of QGD in NAFLD model rats using comprehensive network pharmacology, molecular docking and in vivo verification strategies.

METHODS

Active components and targets of QGD were obtained from public database. The overlapped genes between QGD and NAFLD targets were analyzed by enrichment analysis. Active components and targets were used to predict molecular docking analysis. Finally, seven key targets were screened out and the gene expression were verified in the NAFLD rat's liver tissues after QGD treatment.

RESULTS

Fifty-eight common QGD therapeutic targets were associated with NAFLD. Molecular docking demonstrated that seven targets had strong binding ability for the corresponding active ingredients. GO analysis identified 18 biological process entries, which were mainly related to regulation of lipid storage, lipid localization and peptide transport. KEGG analysis identified multiple signaling pathways, which were mainly associated with tumor necrosis factor signaling and NAFLD. In vivo data confirmed that the effect of QGD in the treatment of NAFLD was mainly exerted through improving liver steatosis and inflammatory cell infiltration. Additionally, QGD upregulated the expression of MAPK8 and ESR1 and downregulated the transcriptional expression of IL6, VEGFA, CASP3, EGFR and MYC. These targets may affect lipid metabolism by regulating lipid storage and inflammation.

CONCLUSION

The integration of results obtained in silico and in vivo indicated that QGD regulates multiple targets, biological processes and signaling pathways in NAFLD, which may represent a complex molecular mechanism by which QGD improves NAFLD.Key messagesQGD intervention is related to multiple biological processes such as inflammation, oxidation and cell apoptosis in NAFLD.Lipid and atherosclerosis, TNF signaling pathway, IL-17 signaling pathway, non-alcoholic fatty liver disease and AGE-RAGE signaling pathway in diabetic complications are the main pathways for QGD intervention NAFLD.The active components of QGD can form good binding with relevant target proteins through intermolecular forces, exhibiting excellent docking activity.

Lipid droplet deposition in the regenerating liver: A promoter, inhibitor, or bystander?

Liver regeneration (LR) is a complex process involving intricate networks of cellular connections, cytokines, and growth factors. During the early stages of LR, hepatocytes accumulate lipids, primarily triacylglycerol, and cholesterol esters, in the lipid droplets. Although it is widely accepted that this phenomenon contributes to LR, the impact of lipid droplet deposition on LR remains a matter of debate. Some studies have suggested that lipid droplet deposition has no effect or may even be detrimental to LR. This review article focuses on transient regeneration-associated steatosis and its relationship with the liver regenerative response.

Impact of endothelial nitric oxide synthase activation on accelerated liver regeneration in a rat ALPPS model

BACKGROUND

Although the associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) induces more rapid liver regeneration than portal vein embolization, the mechanism remains unclear.

AIM

To assess the influence of inflammatory cytokines and endothelial nitric oxide synthase (eNOS) activation on liver regeneration in ALPPS.

METHODS

The future liver remnant/body weight (FLR/BW) ratio, hepatocyte proliferation, inflammatory cytokine expression, and activation of the Akt-eNOS pathway were evaluated in rat ALPPS and portal vein ligation (PVL) models. Hepatocyte proliferation was assessed based on Ki-67 expression, which was confirmed using immunohistochemistry. The serum concentrations of inflammatory cytokines were measured using enzyme linked immune-solvent assays. The Akt-eNOS pathway was assessed using western blotting. To explore the role of inflammatory cytokines and NO, Kupffer cell inhibitor gadolinium chloride (GdCl₃), NOS inhibitor N-nitro-arginine methyl ester (L-NAME), and NO enhancer molsidomine were administered intraperitoneally.

RESULTS

The ALPPS group showed significant FLR regeneration (FLR/BW: 1.60% ± 0.08%, P < 0.05) compared with that observed in the PVL group (1.33% ± 0.11%) 48 h after surgery. In the ALPPS group, serum interleukin-6 expression was suppressed using GdCl₃ to the same extent as that in the PVL group. However, the FLR/BW ratio and Ki-67 labeling index were significantly higher in the ALPPS group administered GdCl₃ (1.72% ± 0.19%, P < 0.05; 22.25% ± 1.30%, P < 0.05) than in the PVL group (1.33% ± 0.11% and 12.78% ± 1.55%, respectively). Phospho-Akt Ser⁴⁷³ and phospho-eNOS Ser¹¹⁷⁷ levels were enhanced in the ALPPS group compared with those in the PVL group. There was no difference between the ALPPS group treated with L-NAME and the PVL group in the FLR/BW ratio and Ki-67 labeling index. In the PVL group treated with molsidomine, the FLR/BW ratio and Ki-67 labeling index increased to the same level as in the ALPPS group.

CONCLUSION

Early induction of inflammatory cytokines may not be pivotal for accelerated FLR regeneration after ALPPS, whereas Akt-eNOS pathway activation may contribute to accelerated regeneration of the FLR.

The role of gut microbiota in liver regeneration

The liver has unique regeneration potential, which ensures the continuous dependence of the human body on hepatic functions. As the composition and function of gut microbiota has been gradually elucidated, the vital role of gut microbiota in liver regeneration through gut-liver axis has recently been accepted. In the process of liver regeneration, gut microbiota composition is changed. Moreover, gut microbiota can contribute to the regulation of the liver immune microenvironment, thereby modulating the release of inflammatory factors including IL-6, TNF-α, HGF, IFN-γ and TGF-β, which involve in different phases of liver regeneration. And previous research have demonstrated that through enterohepatic circulation, bile acids (BAs), lipopolysaccharide, short-chain fatty acids and other metabolites of gut microbiota associate with liver and may promote liver regeneration through various pathways. In this perspective, by summarizing gut microbiota-derived signaling pathways that promote liver regeneration, we unveil the role of gut microbiota in liver regeneration and provide feasible strategies to promote liver regeneration by altering gut microbiota composition.

miR-182-5p promotes hepatocyte-stellate cell crosstalk to facilitate liver regeneration

A unique feature of the liver is its high regenerative capacity, which is essential to maintain liver homeostasis. However, key regulators of liver regeneration (LR) remain ill-defined. Here, we identify hepatic miR-182-5p as a key regulator of LR. Suppressing miR-182-5p, whose expression is significantly induced in the liver of mice post two-thirds partial hepatectomy (PH), abrogates PH-induced LR in mice. In contrast, liver-specific overexpression of miR-182-5p promotes LR in mice with PH. Overexpression of miR-182-5p failed to promote proliferation in hepatocytes, but stimulates proliferation when hepatocytes are cocultured with stellate cells. Mechanistically, miR-182-5p stimulates Cyp7a1-mediated cholic acid production in hepatocytes, which promotes hedgehog (Hh) ligand production in stellate cells, leading to the activation of Hh signaling in hepatocytes and consequent cell proliferation. Collectively, our study identified miR-182-5p as a critical regulator of LR and uncovers a Cyp7a1/cholic acid-dependent mechanism by which hepatocytes crosstalk to stellate cells to facilitate LR.

Hepatic miR-182-5p is identified as a key regulator of liver regeneration by stimulating Cyp7a1-mediated cholic acid production in hepatocytes and activating hedgehog (Hh) signaling, consequently increasing cell proliferation.

Evolution of associating liver partition and portal vein ligation for staged hepatectomy from 2012 to 2021: A bibliometric analysis. Review

BACKGROUND

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) has become increasingly popular during the past few decades, and its indications have extended from patients with normal liver to post-chemotherapy patients and even patients with cirrhosis. However, few studies have assessed the publications in relation to ALPPS.

METHODS

Web of Science was searched to identify studies related to ALPPS published from 2012 to 2021. The analysis was performed using the bibliometric package (Version 3.1.0) in R software.

RESULTS

In total, 486 publications were found. These articles were published in 159 journals and authored by 2157 researchers from 694 organizations. The most prolific journal was Annals of Surgery (24 articles and 1170 citations). The most frequently cited article was published in Annals of Surgery (average citations, 72.7; total citations, 727). China was the most productive country for ALPPS publications but had comparatively less interaction with other countries. Both thematic evolution and co-occurrence network analysis showed low numbers of topics such as failure, resection, and safety among the publications but large numbers of highly cited papers on outcomes, prediction, mechanisms, multicenter analysis, and novel procedures such as liver venous deprivation. A total of 196 studies focused the clinical application of ALPPS, and most studies were IDEAL Stages I and II. The specific mechanism of ALPPS liver regeneration remains unclear.

CONCLUSIONS

This is the first bibliometric analysis offering an overview of the development of ALPPS research publications. Our findings identified prominent studies, countries, institutions, journals, and authors to indicate the future direction of ALPPS research. The role of ALPPS in liver regeneration and the long-term results of ALPPS need further study. Future research directions include comparison of ALPPS with portal vein embolization, liver venous deprivation, and other two-stage hepatectomies as well as patients' quality of life after ALPPS.

SiNiSan alleviates liver injury by promoting hepatic stem cell differentiation via Wnt/β-catenin signaling pathway

BACKGROUND

SiNiSan, a Traditional Chinese Medicine containing Radix Bupleuri, Radix Paeoniae Alba, Fructus Aurantii Immaturus, and Radix Glycyrrhizae, has been shown to be clinically effective in treating liver damage, its underlying molecular mechanisms however remains unclear.

PURPOSE

The aim of the current study was to understand the molecular mechanisms of SiNiSan in the treatment of liver damage utilizing mice and cell culture models.

METHODS

Here, mice were gavaged with 0.2% CCl4 to obtain acute liver injury model and with alcohol to obtain chronic liver injury model. H&E staining was performed to detect liver histomorphology. HPLC-MS was performed to analyze the composition of SiNiSan decoction and SiNiSan-medicated serum (SMS). In addition, western blots were done to analyze the representative protein expression in Wnt/β-catenin signaling. Immunofluorescence staining was done to analyze the protein levels in WB-F344 cells. Finally, in an attempt to measure the influence of SiNiSan on liver regeneration in rats, we constructed a rats partial hepatectomy models.

RESULTS

We demonstrated that SiNiSan treatment mitigated liver damage in mice, as evidenced by the decrease in serum AST and ALT levels, as well as improved liver tissue morphology. HPLC-MS results showed that SMS contained a variety of components from the SiNiSan decoction. Next, our results showed that SMS reduced the expression of α-fetoprotein (AFP) and enhanced the expression of albumin (ALB) and cytokeratin 19 (CK19) in WB-F344 cells. Further, SMS treatment induced the accumulation of β-catenin. After 14 days of SMS treatment, β-catenin protein underwent nuclear translocation and bound to the LEF1 receptor in the nucleus, which regulated c-Myc and Cyclin D1 factors to activate Wnt/β-catenin signaling and promoted differentiation of WB-F344 cells. In addition, we demonstrated that SiNiSan increased liver regeneration in rat hepatectomy.

CONCLUSION

Collectively, the current study revealed that SiNiSan alleviated the acute liver injury induced by CCl4 as well as the chronic liver damage triggered by alcohol and sucrose in vitro. Concurrently, SMS treatment induced hepatic stem cell differentiation by activating Wnt/β-catenin signaling in vivo. Further study showed that SiNiSan promoted the regeneration of rats liver. The current study provides a theoretical basis for the clinical treatment of liver-related diseases with SiNiSan.

Decellularized extracellular matrix mediates tissue construction and regeneration

Contributing to organ formation and tissue regeneration, extracellular matrix (ECM) constituents provide tissue with three-dimensional (3D) structural integrity and cellular-function regulation. Containing the crucial traits of the cellular microenvironment, ECM substitutes mediate cell-matrix interactions to prompt stem-cell proliferation and differentiation for 3D organoid construction in vitro or tissue regeneration in vivo. However, these ECMs are often applied generically and have yet to be extensively developed for specific cell types in 3D cultures. Cultured cells also produce rich ECM, particularly stromal cells. Cellular ECM improves 3D culture development in vitro and tissue remodeling during wound healing after implantation into the host as well. Gaining better insight into ECM derived from either tissue or cells that regulate 3D tissue reconstruction or organ regeneration helps us to select, produce, and implant the most suitable ECM and thus promote 3D organoid culture and tissue remodeling for in vivo regeneration. Overall, the decellularization methodologies and tissue/cell-derived ECM as scaffolds or cellular-growth supplements used in cell propagation and differentiation for 3D tissue culture in vitro are discussed. Moreover, current preclinical applications by which ECM components modulate the wound-healing process are reviewed.

Action Mechanism Underlying Improvement Effect of Fuzi Lizhong Decoction on Nonalcoholic Fatty Liver Disease: A Study Based on Network Pharmacology and Molecular Docking

OBJECTIVE

This study aimed to decipher the bioactive compounds and potential mechanism of traditional Chinese medicine (TCM) formula Fuzi Lizhong Decoction (FLD) for nonalcoholic fatty liver disease (NAFLD) treatment via an integrative network pharmacology approach.

METHODS

The candidate compounds of FLD and its relative targets were obtained from the TCMSP and PharmMapper web server, and the intersection genes for NAFLD were discerned using OMIM, GeneCards, and DisGeNET. Then, the PPI and component-target-pathway networks were constructed. Moreover, GO enrichment and KEGG pathway analysis were performed to investigate the potential signaling pathways associated with FLD's effect on NAFLD. Eventually, molecular docking simulation was carried out to validate the binding affinity between potential core components and key targets.

RESULTS

A total of 143 candidate active compounds and 129 relative drug targets were obtained, in which 61 targets were overlapped with NAFLD. The PPI network analysis identified ALB, MAPK1, CASP3, MARK8, and AR as key targets, mainly focusing on cellular response to organic cyclic compound, steroid metabolic process, and response to steroid hormone in the biological processes. The KEGG pathway analysis demonstrated that 16 signaling pathways were closely correlated with FLD's effect on NALFD with cancer pathways, Th17 cell differentiation, and IL-17 signaling pathways as the most significant ones. In addition, the molecular docking analysis revealed that the core active compounds of FLD, such as 3'-methoxyglabridin, chrysanthemaxanthin, and Gancaonin H, had a high binding activity with such key targets as ALB, MAPK1, and CASP3.

CONCLUSIONS

This study suggested that FLD exerted its effect on NAFLD via modulating multitargets with multicompounds through multipathways. It also demonstrated that the network pharmacology-based approach might provide insights for understanding the interrelationship between complex diseases and interventions of the TCM formula.

Associating liver partition and portal vein ligation for staged hepatectomy in the treatment of colorectal cancer liver metastases

Colorectal cancer (CRC) is a common malignancy of the digestive system. Colorectal liver cancer metastasis (CRLM) occurs in approximately 50% of the patients and is the main cause of CRC mortality. Surgical resection is currently the most effective treatment for CRLM. However, given that the remnant liver volume after resection should be adequate, only a few patients are suitable for radical resection. Since Dr. Hans Schlitt first performed the associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) for CRLM in 2012, ALPPS has received considerable attention and has continually evolved in recent years. This review explains the technical origin of the ALPPS procedure for CRLM and evaluates its efficacy, pointing to its favorable postoperative outcomes. We also discuss the patient screening strategies and optimization of ALPPS to ensure long-term survival of patients with CRLM in whom surgery cannot be performed. Finally, further directions in both basic and clinical research regarding ALPPS have been proposed. Although ALPPS surgery is a difficult and high-risk technique, it is still worth exploration by experienced surgeons.

Functional Genomic Screening During Somatic Cell Reprogramming Identifies DKK3 as a Roadblock of Organ Regeneration

Somatic cell reprogramming and tissue repair share relevant factors and molecular programs. Here, Dickkopf-3 (DKK3) is identified as novel factor for organ regeneration using combined transcription-factor-induced reprogramming and RNA-interference techniques. Loss of Dkk3 enhances the generation of induced pluripotent stem cells but does not affect de novo derivation of embryonic stem cells, three-germ-layer differentiation or colony formation capacity of liver and pancreatic organoids. However, DKK3 expression levels in wildtype animals and serum levels in human patients are elevated upon injury. Accordingly, Dkk3-null mice display less liver damage upon acute and chronic failure mediated by increased proliferation in hepatocytes and LGR5+ liver progenitor cell population, respectively. Similarly, recovery from experimental pancreatitis is accelerated. Regeneration onset occurs in the acinar compartment accompanied by virtually abolished canonical-Wnt-signaling in Dkk3-null animals. This results in reduced expression of the Hedgehog repressor Gli3 and increased Hedgehog-signaling activity upon Dkk3 loss. Collectively, these data reveal Dkk3 as a key regulator of organ regeneration via a direct, previously unacknowledged link between DKK3, canonical-Wnt-, and Hedgehog-signaling.

Liver regeneration and liver metastasis

Surgical resection for primary and secondary hepatic neoplasms provides the best chance of cure. Advanced surgical techniques such as portal vein embolisation, two-staged hepatectomy and associated liver partition and portal vein ligation for staged-hepatectomy (ALPPS) have facilitated hepatic resection in patients with previously unresectable, bi-lobar disease. These techniques are frequently employed to ensure favourable clinical outcomes and avoid potentially fatal post-operative complications such as small for size syndrome and post-hepatectomy liver failure. However, they rely on the innate ability of the liver to regenerate. As our knowledge of liver organogenesis, liver regeneration and hepatocarcinogenesis has expanded in recent decades it has come to light that liver regeneration may also drive tumour recurrence. Clinical studies in patients undergoing portal vein embolisation indicate that tumours may progress following the procedure in concordance with liver regeneration and hypertrophy, however overall survival in these patients has not been shown to be worse. In this article, we delve into the mechanisms underlying liver regeneration to better understand the complex ways in which this may affect tumour behaviour and ultimately inform clinical decisions.

SIX1/EYA1 are novel liver damage biomarkers in chronic hepatitis B and other liver diseases

Background

This study aimed to investigate the clinicopathological significance of sine oculis homeobox homolog 1 (SIX1) and eyes absent 1 (EYA1) in patients with chronic hepatitis B (CHB) and other liver diseases.

Methods

SIX1 and EYA1 levels were detected in human serum and liver tissues by enzyme linked immunosorbent assay (ELISA) and immunofluorescent staining method, respectively.

Results

The serum SIX1 and EYA1 levels in 313 CHB patients were 7.24±0.11 and 25.21±0.51 ng/mL, respectively, and these values were significantly higher than those in 33 healthy controls (2.84±0.15 and 13.11±1.01 ng/mL, respectively; P<0.05). Serum SIX1 and EYA1 levels were also markedly increased in patients with numerous other liver diseases, including liver fibrosis, hepatocellular carcinoma, fatty liver disease, alcoholic liver disease, fulminant hepatic failure, autoimmune liver disease, and hepatitis C, compared to the healthy controls (P<0.05). Dynamic observation of these proteins over time in 35 selected CHB patients revealed that SIX1 and EYA1 serum levels increased over an interval. Immunofluorescent staining revealed that both SIX1 and EYA1 were only expressed in hepatic stellate cells (HSCs), and their increased expression was evident in CHB liver tissue.

Conclusions

SIX1 and EYA1 are novel biomarkers of liver damage in patients of CHB and other liver diseases, with potential clinical utility.

IL-1R1 deficiency impairs liver regeneration after 2/3 partial hepatectomy in aged mice

Inflammation has a dual effect: it can protect the body and destroy tissue and cell as well. The purpose of this experiment was to determine the role of IL-1R1 in liver regeneration (LR) after partial hepatectomy (PH) in aged mice. The wild-type (WT, n = 36) and the IL-1R1 knockout (KO, n = 36) 24-month-old C57BL/6J mice underwent two-thirds PH; 33 WT mice underwent sham operation. Liver coefficient was calculated by liver/body weight. The mRNA and protein expressions of genes were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting methods, respectively. Compared with WT mice, liver coefficient was lower in the IL-1R1 KO aged mice at 168 and 192 h (p = 0.039 and p = 0.027). The mRNA transcription of inflammation-related genes and cell cycle-associated genes decreased or delayed. The protein expressions of proliferation-related marker PCNA and proliferation-associated signaling pathway components JNK1, NF-κB and STAT3 reduced or retarded. There was stronger activation of proapoptotic proteins caspase-3, caspase-8 and BAX in the IL-1R1 KO mice at different time points (p < 0.05 or p < 0.01). IL-1R1 KO reduced inflammation and caused impaired liver regeneration after 2/3 partial hepatectomy in aged mice. Maintaining proper inflammation may contribute to regeneration after liver partly surgical resection in the elderly.

Blockade of TRPM7 Alleviates Chondrocyte Apoptosis and Articular Cartilage Damage in the Adjuvant Arthritis Rat Model Through Regulation of the Indian Hedgehog Signaling Pathway

Articular cartilage damage with subsequent impairment of joint function is a common feature of articular diseases, in particular, rheumatoid arthritis and osteoarthritis. While articular cartilage injury mediated by chondrocyte apoptosis is a known major pathological feature of arthritis, the specific mechanisms remain unclear at present. Transient receptor potential melastatin-like seven channel (TRPM7) is reported to play an important regulatory role in apoptosis. This study focused on the effects of TRPM7 on arthritic chondrocyte injury and its underlying mechanisms of action. Sodium nitroprusside (SNP)-induced rat primary chondrocyte apoptosis and rat adjuvant arthritis (AA) were used as in vitro and in vivo models, respectively. Blockage of TRPM7 with 2-APB or specific siRNA resulted in increased chondrocyte viability and reduced toxicity of SNP. Moreover, treatment with 2-APB enhanced the Bcl-2/Bax ratio and reduced cleaved PARP and IL-6, MMP-13 and ADAMTS-5 expression in SNP-treated chondrocytes. Activation of Indian Hedgehog with purmorphamine reversed the protective effects of 2-APB on SNP-induced chondrocyte apoptosis. Blockage of TRPM7 with 2-APB relieved the clinical signs of AA in the rat model and reduced the arthritis score and paw swelling. Similar to findings in SNP-treated chondrocytes, 2-APB treatment increased the Bcl-2/Bax ratio and suppressed cleaved PARP, IL-6, MMP-13, ADAMTS-5, TRPM7, and Indian hedgehog expression in articular cartilage of AA rats. Our collective findings suggest that blockade of TRPM7 could effectively reduce chondrocyte apoptosis and articular cartilage damage in rats with adjuvant arthritis through regulation of the Indian Hedgehog signaling pathway.

Mitochondrial dysfunction attenuates rapid regeneration in livers with toxin-induced fibrosis

BACKGROUND

The mechanism of associating liver partition and portal vein ligation for staged hepatectomy (ALPPS)-induced rapid liver regeneration remains poorly documented, especially in patients with fibrosis. Therefore, this study aims to investigate the underlying mechanism of ALPPS-induced accelerated regeneration in toxin-induced fibrosis models.

METHODS

The ALPPS-induced regeneration model was established in livers with thioacetamide (TAA)-induced fibrosis to determine the regenerative pathways involved in rapid regeneration. Confirmatory experiments were performed in transforming growth factor beta 1 (TGFβ1)-treated AML12 cells and mice with carbon tetrachloride (CCl4)-induced fibrosis. Finally, mitochondrial dysfunction was validated in fibrotic/non-fibrotic patients.

RESULTS

In TAA-induced fibrotic mice, ALPPS-induced regeneration was significantly inferior to that of the control group (P=0.027 at day 2 and P<0.001 at day 7). Furthermore, mitochondria-associated genes were significantly downregulated in TAA-challenged mice. Accordingly, the reduced production of ATP and elevated levels of malondialdehyde indicated disturbances in intracellular energy metabolism during the ALPPS-induced regenerative process after TAA treatment. Further investigations were performed in TGF-β1-treated AML12 cells and CCl4-treated mice, which indicated that mitochondrial dysfunction attenuated the capacity for rapid regeneration after ALPPS.

CONCLUSIONS

In summary, this study revealed that mitochondrial dysfunction led to inferior regeneration in livers with toxin-induced fibrosis and identified new therapeutic targets to improve the feasibility and safety of the ALPPS procedure. Further studies in human patients are required in the future.

Inhibition of TGFβ1 accelerates regeneration of fibrotic rat liver elicited by a novel two-staged hepatectomy

Aims: Emerging evidence is demonstrating that rapid regeneration of remnant liver elicited by associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) may be attenuated in fibrotic livers. However, the molecular mechanisms responsible for this process are largely unknown. It is widely acknowledged that the TGFβ1 signaling axis plays a major role in liver fibrosis. Therefore, the aims of this study were to elucidate the underlying mechanism of liver regeneration during ALPPS with or without fibrosis, specifically focusing on TGFβ1 signaling. Approach: ALPPS was performed in rat models with N-diethylnitrosamine-induced liver fibrosis and no fibrosis. Functional liver remnant regeneration and expression of TGFβ1 were analyzed during the ALPPS procedures. Adeno-associated virus-shTGFβ1 and the small molecule inhibitor LY2157299 (galunisertib) were used separately or in combination to inhibit TGFβ1 signaling in fibrotic rats. Results: Liver regeneration following ALPPS was lower in fibrotic rats than non-fibrotic rats. TGFβ1 was a key mediator of postoperative regeneration in fibrotic liver. Interestingly, AAV-shTGFβ1 accelerated the regeneration of fibrotic functional liver remnant and improved fibrosis, while LY2157299 only enhanced liver regeneration. Moreover, combination treatment elicited a stronger effect. Conclusions: Inhibition of TGFβ1 accelerated regeneration of fibrotic liver, ameliorated liver fibrosis, and improved liver function following ALPPS. Therefore, TGFβ1 is a promising therapeutic target in ALPPS to improve fibrotic liver reserve function and prognosis.

Targeting extracellular vesicles-mediated hepatic inflammation as a therapeutic strategy in liver diseases

Extracellular Vesicles (EVs) are nano- to micro-sized membranous vesicles that can be produced by normal and diseased cells. As carriers of biologically active molecules including proteins, lipids and nucleic acids, EVs mediate cell-to-cell communication and execute diverse functions by delivering their cargoes to specific cell types. Hepatic inflammation caused by virus infection, autoimmunity and malignancy is a common driver of progressive liver fibrosis and permanent liver damage. Emerging evidence has shown that EVs-mediated inflammation as critical player in the progression of liver diseases since they shuttle within the liver as well as between other tissues with inflammatory signals. Therefore, targeting inflammatory EVs could represent a potential therapeutic strategy in liver diseases. Moreover, EVs are emerging as a promising tool for intracellular delivery of therapeutic nucleic acid. In this review, we will discuss not only recent advances on the role of EVs in mediating hepatic inflammation and present strategies for targeted therapy on the context of liver diseases but also the challenging questions that need to be answered in the field.

Network pharmacology reveals the multiple mechanisms of Xiaochaihu decoction in the treatment of non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver (NAFLD) is a chronic disease worldwide, which poses a huge threat to human health. Xiaochaihu decoction is a well-known traditional Chinese medicine prescription. It has been proven effective in treating NAFLD but its mechanism is still unclear.

OBJECTIVE

Multiple mechanisms of Xiaochaihu decoction are explored by identifying and connecting potential targets and active ingredients in the treatment of NAFLD.

METHODS

Active ingredients and related targets of seven herbs were collected from TCMSP database. The related targets of NAFLD were obtained from Genes cards database, TDD and OMIM database. The intersected targets of disease targets and drug targets were input into STRING database to construct protein-protein interaction network. DAVID database was used for GO enrichment analysis and KEGG enrichment analysis.

RESULTS

After screening and removal of duplicates, a total of 145 active ingredients and 105 potential targets were obtained. PPI network manifested that AKT1, IL6, JUN MAPK8 and STAT3 were the key target proteins. The results of GO enrichment analysis mainly involved cytokine receptor binding, cytokine activity, and heme binding. The results of KEGG analysis suggested that the mechanism mainly involved in AGE-RAGE signaling pathway in diabetic complications, Hepatitis C, fluid shear stress and atherosclerosis. The signaling pathways were further integrated as network manner, including AGE-RAGE signaling pathway in diabetic complications, Fluid shear stress and atherosclerosis, Insulin resistance, HIF-1 signaling pathway, Th17 cell differentiation and IL-17 signaling pathway. The network contained immunity regulation, metabolism regulation and oxidative stress regulation.

CONCLUSION

Xiaochaihu decoction plays a key role in the treatment of NAFLD with multiple targets and pathways. Immunity regulation, metabolism regulation and oxidative stress regulation consist of the crucial regulation cores in mechanism.

GRAPHICAL ABSTRACT

Design and workflow of this study.

SHMT2 Promotes Liver Regeneration Through Glycine-activated Akt/mTOR Pathway

BACKGROUND

The development of liver transplantation (LT) is increasingly being limited by the unavailability of liver grafts. Unique regenerative capacity of liver in response to injuries makes living-donor liver transplantation (LDLT) a feasible strategy to meet clinical demands. Serine hydroxymethyl-transferase 2 (SHMT2) serves as the key enzyme in the biosynthesis of glycine. Glycine affects the activity of mammalian target of rapamycin (mTOR), which is important for cellular growth and proliferation. In this study, the effects of SHMT2 on mouse liver regeneration were investigated using a classical partial hepatectomy (PH) model.

METHODS

In vivo, PH was performed on mice with or without knockdown of SHMT2. In vitro, SHMT2 was overexpressed in primary hepatocytes, which were cultured in customized Dulbecco's modified eagle media and LY294002 (an Akt inhibitor). Relevant indexes of liver regeneration, cell proliferation, and Akt/mTOR signal pathways were analyzed.

RESULTS

After PH, the expression levels of SHMT2 fluctuated with time and knockdown of SHMT2 in vivo lowered the regenerative ability of liver, with reduced glycine levels compared to the scramble group. In addition, overexpression of SHMT2 in hepatocytes boosted glycine production while enhancing Akt/mTOR pathway activity. These results were validated by the application of LY294002 in vitro.

CONCLUSIONS

SHMT2 can contribute to liver regeneration after PH, and this is likely related to the activation of Akt/mTOR signaling pathway by its metabolic product, glycine, in hepatocytes. These results might have therapeutic implications for the prognosis of patients undergoing hepatic resection or transplantation.

Yiqi Huoxue Recipe Improves Liver Regeneration in Rats after Partial Hepatectomy via JNK Pathway

The liver is the only visceral organ that exhibits a remarkable capability of regenerating in response to partial hepatectomy (PH) or chemical injury. Improving liver regeneration (LR) ability is the basis for the favourable treatment outcome of patients after PH, which can serve as a potential indicator for postoperative survival. The present study aimed to investigate the protective effects of Yiqi Huoxue recipe (YQHX) on LR after PH in rats and further elucidate its underlying mechanism. A two-thirds PH rat model was used in this study. Wistar rats were randomly divided into four groups: sham-operated, PH, YQHX + PH, and Fuzheng Huayu decoction (FZHY) + PH groups. All rats were sacrificed under anesthesia at 24 and 72 h after surgery. The rates of LR were calculated, and the expression levels of cyclin D1 and c-jun were determined by immunohistochemical staining. The protein levels of p-JNK1/2, JNK1/2, p-c-jun, c-jun, Bax, and Bcl-2 were detected by Western blotting, while the mRNA levels of JNK1, JNK2, c-jun, Bax, and Bcl-2 were examined by real-time polymerase chain reaction (RT-PCR). At the corresponding time points, YQHX and FZHY administration dramatically induced the protein levels of p-JNK1/2 compared to the PH group (p < 0.05), while FZHY + PH group showed prominently increase in p-JNK1/2 protein levels compared to the YQHX + PH group (p < 0.05). A similar trend was observed for the expression levels of p-c-jun. Compared to the PH group, YQHX and FZHY markedly reduced the mRNA and protein expression levels of Bax at 24 h after PH, while those in the FZHY + PH group decreased more obviously (p < 0.05). Besides, in comparison with the PH group, YQHX and FZHY administration predominantly upregulated the mRNA and protein expression levels of Bcl-2 at 24 and 72 h after PH (p < 0.05). In conclusion, YQHX improves LR in rats after PH by inhibiting hepatocyte apoptosis via the JNK signaling pathway.

Model systems for regeneration: Drosophila

Drosophila melanogaster has historically been a workhorse model organism for studying developmental biology. In addition, Drosophila is an excellent model for studying how damaged tissues and organs can regenerate. Recently, new precision approaches that enable both highly targeted injury and genetic manipulation have accelerated progress in this field. Here, we highlight these techniques and review examples of recently discovered mechanisms that regulate regeneration in Drosophila larval and adult tissues. We also discuss how, by applying these powerful approaches, studies of Drosophila can continue to guide the future of regeneration research.

The vaccine adjuvant MPLA activates glycolytic metabolism in mouse mDC by a JNK-dependent activation of mTOR-signaling

INTRODUCTION

The detoxified TLR4-ligand MPLA is a successfully used adjuvant in clinically approved vaccines. However, its capacity to activate glycolytic metabolism in mDC and the influence of MPLA-induced metabolic changes on cytokine secretion are unknown.

AIM

To analyze the capacity of MPLA to activate mDC metabolism and the mechanisms contributing to MPLA-induced metabolism activation and cytokine secretion.

METHODS

C57BL/6 bone-marrow-derived myeloid dendritic cells (mDCs) were stimulated with LPS or MPLA and analyzed for intracellular signaling, cytokine secretion, and metabolic state. mDC were pre-treated with rapamycin (mTOR-inhibitor), U0126, SP600125, SB202190 (MAPK kinase inhibitors), as well as dexamethasone (MAPK- and NFκB-inhibitor) and analyzed for MPLA-induced cytokine secretion and cell metabolic state.

RESULTS

Stimulation of mDCs with either LPS or MPLA resulted in a pronounced, mTOR-dependent activation of glucose metabolism characterized by induction of the Warburg Effect, increased glucose consumption from the culture medium, as well as release of LDH. Compared to LPS, MPLA induced significantly lower cytokine secretion. The activation of mDC metabolism was comparable between LPS- and MPLA-stimulated mDCs. The MPLA-induced cytokine secretion could be partially inhibited using mTOR-, MAP kinase-, and NFκB-inhibitors, whereas the activation of glucose metabolism was shown to depend on both mTOR- and JNK-signaling.

SUMMARY

The MPLA-induced activation of glycolytic metabolism in mouse mDC was shown to depend on a JNK-mediated activation of mTOR-signaling, while both MAPK- and NFB-signaling contributed to pro-inflammatory cytokine secretion. Understanding the mechanisms by which MPLA activates dendritic cells will both improve our understanding of its adjuvant properties and contribute to the future development and safe application of this promising adjuvant.