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Background: Globally, prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is increasing, and there is an urgent need to develop innovative therapies that promote liver regeneration following hepatectomy for this disease. Surgical excision is a key therapeutic approach with curative potential for liver tumors. However, hepatic steatosis can lead to delayed liver regeneration and higher post-operative complication risk. Mesenchymal stem cells-conditioned medium (MSC-CM) is considered a rich source of paracrine factors that can repair tissues and restore function of damaged organs. Meanwhile, hydrogels have been widely recognized to load MSC secretome and achieve sustained release. This study aimed to evaluate the therapeutic effect of hydrogel-encapsulated MSC-CM on liver regeneration following partial hepatectomy (PHx) in a rodent model of diet-induced hepatic steatosis. Methods: Male Lewis rats were fed with a methionine and choline–deficient diet. After 3 weeks of feeding, PHx was performed and rats were randomly allocated into two groups that received hydrogel-encapsulated MSC-CM or vehicle via the intra-mesenteric space of the superior mesenteric vein (SMV). Results: The regeneration of the remnant liver at 30 and 168 h after PHx was significantly accelerated, and the expressions of proliferating cell nuclear antigen were significantly enhanced in the MSC-CM group. MSC-CM treatment significantly increased hepatic ATP and β-hydroxybutyrate content at 168 h after PHx, indicating that MSC-CM fosters regeneration not only in volume but also in functionality. The number of each TUNEL- and cleaved caspase-3 positive nuclei in hepatocytes at 9 h after PHx were significantly decreased in the MSC-CM group, suggesting that MSC-CM suppressed apoptosis. MSC-CM increased serum immunoregulatory cytokine interleukin-10 and interleukin-13 at 30 h after PHx. Additionally, mitotic figures and cyclin D1 expression decreased and hepatocyte size increased in the MSC-CM group, implying that this mode of regeneration was mainly through cell hypertrophy rather than cell division. Conclusions: MSC-CM represents a novel therapeutic approach for patients with MASLD requiring PHx. [ABSTRACT FROM AUTHOR]

The occurrence of poisoning incidents caused by cyanobacterial blooms has aroused wide public concern. Microcystin-leucine arginine (MC-LR) is a well-established toxin produced by cyanobacterial blooms, which is widely distributed in eutrophic waters. MC-LR is not only hazardous to the water environment but also exerts multiple toxic effects including liver toxicity in both humans and animals. However, the underlying mechanisms of MC-LR-induced liver toxicity are unclear. Herein, we used advanced single-cell RNA sequencing technology to characterize MC-LR-induced liver injury in mice. We established the first single-cell atlas of mouse livers in response to MC-LR. Our results showed that the differentially expressed genes and pathways in diverse cell types of liver tissues of mice treated with MC-LR are highly heterogeneous. Deep analysis showed that MC-LR induced an increase in a subpopulation of hepatocytes that highly express Gstm3 , which potentially contributed to hepatocyte apoptosis in response to MC-LR. Moreover, MC-LR increased the proportion and multiple subtypes of Kupffer cells with M1 phenotypes and highly expressed proinflammatory genes. Furthermore, the MC-LR increased several subtypes of CD8+ T cells with highly expressed multiple cytokines and chemokines. Overall, apart from directly inducing hepatocytes apoptosis, MC-LR activated proinflammatory Kupffer cell and CD8+ T cells, and their interaction may constitute a hostile microenvironment that contributes to liver injury. Our findings not only present novel insight into underlying molecular mechanisms but also provide a valuable resource and foundation for additional discovery of MC-LR-induced liver toxicity. [Display omitted] [ABSTRACT FROM AUTHOR]

The genome duplication program is affected by multiple factors in vivo , including developmental cues, genotoxic stress, and aging. Here, we monitored DNA replication initiation dynamics in regenerating livers of young and old mice after partial hepatectomy to investigate the impact of aging. In young mice, the origin firing sites were well defined; the majority were located 10–50 kb upstream or downstream of expressed genes, and their position on the genome was conserved in human cells. Old mice displayed the same replication initiation sites, but origin firing was inefficient and accompanied by a replication stress response. Inhibitors of the ATR checkpoint kinase fully restored origin firing efficiency in the old mice but at the expense of an inflammatory response and without significantly enhancing the fraction of hepatocytes entering the cell cycle. These findings unveil aging-dependent replication stress and a crucial role of ATR in mitigating the stress-associated inflammation, a hallmark of aging. [Display omitted] • Partial hepatectomy enables in vivo mapping of DNA replication origins in mouse livers • Most origins are located 10–50 kb upstream or downstream of expressed genes • An aging-dependent reduction in origin firing is mediated by the ATR checkpoint • ATR inhibitors restore origin firing in old mice but lead to liver inflammation In vivo DNA replication dynamics in regenerating mouse livers unveil aging-dependent decline in replication efficiency and a crucial role of the ATR checkpoint kinase in mitigating inflammation associated with the decline. [ABSTRACT FROM AUTHOR]

The editorial in "Frontiers in Endocrinology" discusses the role of Hepatocyte nuclear factor 4 alpha (HNF4a) as a master regulator of liver-specific transcription, with implications for various human diseases. The article covers the evolutionary origins of HNF4a, mutations linked to diabetes, and the structure of the protein. Research on HNF4a's role in liver regeneration, metabolism, and intestines is highlighted, along with potential future research directions. The article emphasizes the importance of HNF4a in various tissues and its potential therapeutic implications. [Extracted from the article]

High-throughput transcriptomics (HTTr) is increasingly being used to identify molecular targets of chemicals that can be linked to adverse outcomes. Cell proliferation (CP) is an important key event in chemical carcinogenesis. Here, we describe the construction and characterization of a gene expression biomarker that is predictive of the CP status in human and rodent tissues. The biomarker was constructed from 30 genes known to be increased in expression in prostate cancers relative to surrounding tissues and in cycling human MCF-7 cells after estrogen receptor (ER) agonist exposure. Using a large compendium of gene expression profiles to test utility, the biomarker could identify increases in CP in (i) 308 out of 367 tumor vs. normal surrounding tissue comparisons from 6 human organs, (ii) MCF-7 cells after activation of ER, (iii) after partial hepatectomy in mice and rats, and (iv) the livers of mice and rats after exposure to nongenotoxic hepatocarcinogens. The biomarker identified suppression of CP (i) under conditions of p53 activation by DNA damaging agents in human cells, (ii) in human A549 lung cells exposed to therapeutic anticancer kinase inhibitors (dasatinib, nilotnib), and (iii) in the mouse liver when comparing high levels of CP at birth to the low background levels in the adult. The responses using the biomarker were similar to those observed using conventional markers of CP including PCNA, Ki67, and BrdU labeling. The CP biomarker will be a useful tool for interpretation of HTTr data streams to identify CP status after exposure to chemicals in human cells or in rodent tissues. [ABSTRACT FROM AUTHOR]

Despite being the standard treatment for end-stage liver disease, liver transplantation has limitations like donor scarcity, high surgical costs, and immune rejection risks. Mesenchymal stem cells (MSCs) and their derivatives offer potential for liver regeneration and transplantation. MSCs, known for their multipotency, low immunogenicity, and ease of obtainability, can differentiate into hepatocyte-like cells and secrete bioactive factors that promote liver repair and reduce immune rejection. However, the clinical application of MSCs is limited by risks such as aberrant differentiation and low engraftment rates. As a safer alternative, MSC-derived secretomes and extracellular vesicles (EVs) offer promising therapeutic benefits, including enhanced graft survival, immunomodulation, and reduced ischemia–reperfusion injury. Current research highlights the efficacy of MSC-derived therapies in improving liver transplant outcomes, but further studies are necessary to standardize clinical applications. This review highlights the potential of MSCs and EVs to address key challenges in liver transplantation, paving the way for innovative therapeutic strategies. [ABSTRACT FROM AUTHOR]

Post-hepatectomy liver failure (PHLF) remains a significant risk for patients undergoing partial hepatectomy (PHx). Reliable prognostic markers and treatments to enhance liver regeneration are lacking. Plasma nanoparticles, including lipoproteins, exosomes, and extracellular vesicles (EVs), can reflect systemic and tissue-wide proteostasis and stress, potentially aiding liver regeneration. However, their role in PHLF is still unknown. Methods: Our study included nine patients with hepatocellular carcinoma (HCC) undergoing PHx: three patients with PHLF, three patients undergoing the associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) procedure, and three matched controls without complications after PHx. Patient plasma was collected before PHx as well as 1 and 5 days after. EVs were isolated by ultracentrifugation, and extracted proteins were subjected to quantitative mass spectrometry using a super-SILAC mix prepared from primary and cancer cell lines. Results: We identified 2625 and quantified 2570 proteins in the EVs of PHx patients. Among these, 53 proteins were significantly upregulated and 32 were downregulated in patients with PHLF compared to those without PHLF. Furthermore, 110 proteins were upregulated and 78 were downregulated in PHLF patients compared to those undergoing ALPPS. The EV proteomic signature in PHLF indicates significant disruptions in protein translation, proteostasis, and intracellular vesicle biogenesis, as well as alterations in proteins involved in extracellular matrix (ECM) remodelling and the metabolic and cell cycle pathways, already present before PHx. Conclusions: Longitudinal proteomic analysis of the EVs circulating in the plasma of human patients undergoing PHx uncovers proteomic signatures associated with PHLF, which reflect dying hepatocytes and endothelial cells and were already present before PHx. [ABSTRACT FROM AUTHOR]

Gut metabolites via the portal vein affect several liver functions, including regeneration. Here, we investigated gut microbiota-derived metabolites in portal and peripheral serum during liver regeneration. We developed rat models of 70% partial hepatectomy (PHx) with and without prior gut microbiota modulation by 3-wk antibiotic (Abx) treatment. Sham without Abx were used as controls and compared with sham with Abx. Liver regeneration at day 2 following PHx was assessed by expression of proliferating cell nuclear antigen (PCNA) protein in liver tissues and cyclin genes in primary hepatocytes. High-performance liquid chromatography-mass spectrometry-based portal and peripheral venous serum metabolomics were performed to identify differentially altered metabolites (DAMs). Compared with controls, rat livers at day 2 post-PHx showed significant upregulation in the average number of PCNA-positive cells, which positively correlated with the expression of cell cycle genes in hepatocytes. In Abx-treated PHx, we observed reduced PCNA-positivity and downregulation in gene expression of various cyclins in hepatocytes compared with PHx. We identified 224 DAMs between controls versus PHx and 189 DAMs between Abx-treated PHx versus PHx in portal serum. Many common DAMs showed opposite expression trends in PHx versus controls and then Abx + PHx versus PHx in portal serum, such as sphingosine-1-phosphate and deoxycholic acid. In vitro studies with deoxycholic acid demonstrated that it enhanced the viability and proliferation of primary hepatocytes and hepatocyte organoids. The study underscores the critical role of deoxycholic acid in portal blood in enhancing hepatocyte proliferation and, subsequently, liver regeneration. NEW & NOTEWORTHY: Based on metabolome analysis of portal and peripheral serum in 70% partial hepatectomy (PHx) models, we described previously unreported metabolic alterations related to liver regeneration. The study also identified substantial changes among portal and peripheral serum metabolites in both control and PHx rats. We identified the potential role of portal vein metabolites including sphingosine-1-phosphate and deoxycholic acid in promoting hepatocyte proliferation and, hence, liver regeneration following PHx. [ABSTRACT FROM AUTHOR]

Apoptosis, inflammation, and wound healing are critical pathophysiological events associated with various liver diseases. Currently, there is a lack of in vivo approaches to study hepatocyte apoptosis-induced liver injury and repair. To address this critical knowledge gap, we developed a unique genetically modified mouse model, namely, 3-Transgene (Tg) with inducible Hepatocyte-Specific Apoptosis Phenotype (3xTg-iHAP) in this study. The 3xTg-iHAP mice possess three transgenes including Alb-Cre, Rosa26-rtTA, and tetO-Fasl on a B6 background. These mice are phenotypically normal, viable, and fertile. After subcutaneous administration of a single dose of doxycycline (5 mg/kg, Dox) to 3xTg-iHAP mice, we observed a complete histological spectrum of sterile liver wound-healing responses: asymptomatic hepatocyte apoptosis at 8 h, necrotic liver injury and sterile inflammation at 48 h, followed by hepatocyte mitosis and regeneration within 7 days. During the injury phase, the mice exhibited an increase in the biomarkers of alanine aminotransferase (ALT), chemokine (C-X-C motif) ligand 1 (CXCL1), and IL-6 in peripheral blood, as well as α-smooth muscle actin (α-SMA) protein in liver tissues. Conversely, the mice displayed a decrease in these markers in the recovery phase. Remarkably, this model shows that the sterile liver injury following elevated hepatocyte apoptosis is associated with an increase in myeloid cells in the liver. Within 7 days post-Dox administration, the liver of Dox-treated 3xTg-iHAP mice displays a normal histological structure, indicating the completion of wound healing. Together, we established a novel mouse model of injury and regeneration induced by hepatocyte apoptosis. This tool provides a robust in vivo platform for studying the pathophysiology of sterile liver inflammation, regeneration, and new therapeutic interventions for liver diseases. NEW & NOTEWORTHY: Bu et al. present a triple-transgenic mouse model, namely, 3xTg-iHAP mice that are engineered to explore hepatocyte apoptosis-triggered sterile liver injury and regeneration. This model demonstrates a full spectrum of liver wound-healing responses from asymptomatic apoptosis to injury, myeloid cell-dominant sterile inflammation, and repair after induction of hepatocyte-specific apoptosis. The robust nature of this model makes it an invaluable in vivo tool for studying sterile liver inflammation, regeneration, and new therapeutic strategies. [ABSTRACT FROM AUTHOR]

Transglutaminase 2 (Tgm2) plays an essential role in hepatic repair following prolonged toxic injury. During cholestatic liver injury, the intrahepatic cholangiocytes undergo dynamic tissue expansion and remodelling, referred to as ductular reaction (DR), which is crucial for liver regeneration. However, the molecular mechanisms governing the dynamics of active cells in DR are still largely unclear. Here, we generated Tgm2‐knockout mice (Tgm2−/−) and Tgm2‐CreERT2‐Rosa26‐mTmG flox/flox (Tgm2CreERT2‐R26T/Gf/f) mice and performed a three‐dimensional (3D) collagen gel culture of mouse hepatocytes to demonstrate how Tgm2 signalling is involved in DR to remodel intrahepatic cholangiocytes. Our results showed that the deletion of Tgm2 adversely affected the functionality and maturity of the proliferative cholangiocytes in DR, thus leading to more severe cholestasis during DDC‐induced liver injury. Additionally, Tgm2 hepatocytes played a crucial role in the regulation of DR through metaplasia. We unveiled that Tgm2 regulated H3K4me3Q5ser via serotonin to promote BMP signalling activation to participate in DR. Besides, we revealed that the activation or inhibition of BMP signalling could promote or suppress the development and maturation of cholangiocytes in DDC‐induced DR. Furthermore, our 3D collagen gel culture assay indicated that Tgm2 was vital for the development of cholangiocytes in vitro. Our results uncovered a considerable role of BMP signalling in controlling metaplasia of Tgm2 hepatocytes in DR and revealed the phenotypic plasticity of mature hepatocytes. [ABSTRACT FROM AUTHOR]

Background & Aims: Ammonia is metabolized into urea in the liver. In acute liver failure (ALF), ammonia has been associated with survival. However, urea variation has been poorly studied. Methods: Observational cohort including ALF patients from Curry Cabral Hospital (Lisbon, Portugal) and Clinic Hospital (Barcelona, Spain) between 10/2010 and 01/2023. The United States ALF Study Group cohort was used for external validation. Primary exposures were serum ammonia and urea on ICU admission. Primary endpoint was 30‐day transplant‐free survival (TFS). Secondary endpoint was explanted liver weight. Results: Among 191 ALF patients, median (IQR) age was 46 (32; 57) years and 85 (44.5%) were males. Overall, 86 (45.0%) patients were transplanted and 75 (39.3%) died. Among all ALF patients, following adjustment for age, sex, body weight, and aetiology, higher ammonia or lower urea was independently associated with higher INR on ICU admission (p <.009). Among all ALF patients, following adjustment for sex, aetiology, and lactate, higher ammonia was independently associated with lower TFS (adjusted odds ratio (95% confidence interval [CI]) = 0.991 (0.985; 0.997); p =.004). This model predicted TFS with good discrimination (area under receiver operating curve [95% CI] = 0.78 [0.75; 0.82]) and reasonable calibration (R2 of 0.43 and Brier score of 0.20) after external validation. Among transplanted patients, following adjustment for age, sex, actual body weight, and aetiology, higher ammonia (p =.024) or lower (p <.001) urea was independently associated with lower explanted liver weight. Conclusions: Among ALF patients, serum ammonia and urea were associated with ALF severity. A score incorporating serum ammonia predicted TFS reasonably well. [ABSTRACT FROM AUTHOR]

Background and Aim: Even with advancement of medical technologies, liver transplantation still faces several major challenges. Hence, other treatment modalities are urgently needed for patients with end‐stage liver disease. Stem cells from human exfoliated deciduous teeth (SHED) was discovered to have highly proliferative and pluripotent properties; including differentiation into hepatocyte‐like cells. This study aims to investigate the capability of intrasplenic transplanted SHED and SHED‐Hep cells in inducing proliferation of stem cells and native hepatocytes in order to accelerate liver regeneration in liver fibrosis mice models. Methods: Three carbon tetrachloride (CCl4)‐injured male mice groups were used in this study. Two of those groups were transplanted with either SHED or SHED‐Hep, while the other did not undergo transplantation. One age‐ and sex‐ matched healthy mice group was used as control. All specimens were immunohistochemically stained with anti‐Ki‐67 antibodies and anti‐proliferating cell nuclear antigen (PCNA) antibodies before counter stained with hematoxylin–eosin. Results: Anti‐Ki‐67 antibodies staining: at both 8 and 12 weeks, proliferating activity was predominantly seen on both SHED‐ and SHED‐Hep‐transplanted CCl4‐injured mice groups, while control and non‐transplanted CCl4‐injured mice group showed little to no sign of proliferation activity. Anti‐PCNA staining: at both 8 and 12 weeks, significant proliferating activity was detected by PCNA staining, mainly on stem cells population area on SHED‐ and SHED‐Hep‐treated group. Conclusions: In conclusion, this study has provided the evidence that transplantation of SHED or SHED‐Hep on liver‐injured mice induced proliferation of both transplanted stem cells and native liver cells in order to accelerate liver regeneration. [ABSTRACT FROM AUTHOR]

Liver fibrosis is characterized by abnormal accumulation of extracellular matrix proteins, disrupting normal liver function. Despite its significant health impact, effective treatments remain limited. Here, we present the development of engineered lipid nanoparticles (LNPs) for targeted RNA therapeutic delivery in the liver. We investigated the therapeutic potential of modulating the G2 and S-phase expressed 1 (GTSE1) protein for treating liver fibrosis. Through screening, we identified P13 8Y LNP as a potent candidate with superior delivery efficiency and lower toxicity. Using these engineered LNPs, we successfully delivered siGTSE1 to hepatocytes, significantly reducing collagen accumulation and restoring liver function in a fibrosis animal model. Additionally, GTSE1 downregulation altered miRNA expression and upregulated hepatocyte nuclear factor 4 alpha (HNF4α). These findings suggest that therapeutic gene silencing of GTSE1 is a promising strategy for treating liver fibrosis by regenerating liver phenotypes and functions. A significant decrease in GTSE1 levels, achieved by targeted delivery of siGTSE1 using engineered LNPs, leads to reduced collagen deposition and restoration of liver function through alterations in liver fibrosis-related miRNA expression and the upregulation of hepatocyte nuclear factor 4 alpha (HNF4⍺). [Display omitted] [ABSTRACT FROM AUTHOR]

Experimental models using 2/3 partial hepatectomy or chemical injury have helped identify the pathways associated with liver regeneration (LR). Several microRNAs (miRNAs) have been identified as modulators of LR, but the molecular mechanisms underlying their activity are still unclear. Given the development of new therapies targeting miRNAs, this is an important question to address. This review discusses recent studies exploring the molecular mechanisms of miRNA-dependent regulation of LR. In particular, the finding that circ-RBM23 promotes LR by sequestering cytoplasmic miRNA139-5p has furthered the understanding of the molecular mechanisms underlying circRNA activity. Interestingly, although miRNAs are generally considered negative regulators of their target mRNAs, miRNAs182-5p promotes LR by upregulating Cyp7a. Furthermore, mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) were shown to enhance LR after 2/3 partial hepatectomy by releasing miRNAs that inhibit gene expression to promote an anti-inflammatory response or miRNA-regulatory factors. Since the administration of MSCs-EVs has no hepatotoxic side effects, this may represent a therapeutic strategy to promote LR. miRNAs also mediate LR after chemical injury. This is the case for miR194 and miR21, whose downregulation activates pro-regeneration pathways to ameliorate acetaminophen-induced liver injury. In addition, the downregulation of miR21 has been shown to improve autophagy and haemostasis after acetaminophen overdose. Although further studies are needed to improve their efficacy as therapeutics, the evidence gathered in this review has led to a better understanding of the molecular mechanisms associated with the control of LR by miRNAs. [ABSTRACT FROM AUTHOR]

Aimed to explore the mechanisms and targets of Diwu Yanggan Capsule (DWYG), a traditional Chinese medicine in liver regeneration, we used the TCMSP to obtain the active ingredients and targets of DWYG and the GEO database to obtain the DEGs related to liver regeneration. We also searched for liver regeneration-related genes in disease databases and integrated them with the herbal and GEO data to screen for potential targets of DWYG in liver regeneration. Enrichment analysis using R language and molecular docking of the key targets and active ingredients were constructed. We found 73 potential targets of DWYG in liver regeneration and revealed that DWYG may act through pathways such as MAPK, TNF, and IL-17. We also found that quercetin was a major component of DWYG with low binding energy to three key targets. Our results suggest that DWYG can facilitate liver regeneration and quercetin may be its core ingredient. [ABSTRACT FROM AUTHOR]

Although liver transplantation (LT) is an effective strategy for end-stage liver diseases, the shortage of donor organs and the immune rejection hinder its widespread implementation in clinical practice. Mesenchymal stem cells (MSCs) transplantation offers a promising approach for patients undergoing liver transplantation due to their immune regulatory capabilities, hepatic protection properties, and multidirectional differentiation potential. In this review, we summarize the potential applications of MSCs transplantation in various LT scenarios. MSCs transplantation has demonstrated effectiveness in alleviating hepatic ischemia-reperfusion injury, enhancing the viability of liver grafts, preventing acute graft-versus-host disease, and promoting liver regeneration in split LT therapy. We also discuss the clinical progress, and explore the immunomodulatory functions of MSCs in response to both adaptive and innate immune responses. Furthermore, we emphasize the interactions between MSCs and different immune cells, including T cells, B cells, plasma cells, natural killer cells, dendritic cells, Kupffer cells, and neutrophils, to provide new insights into the immunomodulatory properties of MSCs in adoptive cell therapy. [ABSTRACT FROM AUTHOR]

Acute liver failure (ALF) involves extensive necrosis of liver cells and severe impairment of liver function. Hepatocyte transplantation holds promise for treating ALF by swiftly supporting liver functions and promoting liver regeneration. However, the scarcity of suitable cell sources requires strategies to obtain enough functional hepatocyte‐like cells (HLCs) and optimize their in vivo transplantation efficiency. A DNA hexahedral nanostructure (DHN) is developed loaded with microRNA‐122 to efficiently induce hepatic differentiation of human adipose‐derived mesenchymal stem cells into HLCs. These HLCs can serve as alternative hepatocyte sources, as confirmed by expression of liver‐specific genes and proteins, and the restoration of liver functions. To enhance in vivo survival efficiency of HLCs, a versatile scaffold is also created by 3D printing the calcium‐cross‐linked mixture bioink composed of sodium alginate, gelatin, and silk fibroin with excellent ROS scavenging capabilities. The scaffold is infused with chitosan‐DHN hydrogel containing HLCs for tissue engineering orthotopic transplantation in CCl4‐induced ALF mice. The transplanted composite scaffold‐HLCs successfully repair tissue necrosis in the liver injury area of mice and regulate expressions of genes and proteins associated with inflammation, oxidative stress, and hepatocyte function. Collectively, this study offers a novel approach and strategy for identifying alternative hepatocyte sources and treating ALF. [ABSTRACT FROM AUTHOR]

Nucleostemin (NS) plays a role in liver regeneration, and aging reduces its expression in the baseline and regenerating livers following 70% partial hepatectomy (PHx). Here we interrogate the mechanism controlling NS expression during liver regeneration and aging. The NS promoter was analyzed by TRANSFAC. Functional studies were performed using cell-based luciferase assay, endogenous NS expression in Hep3B cells, mouse livers with a gain-of-function mutation of C/EBPα (S193D), and mouse livers with C/EBPα knockdown. We found a CAAT box with four C/EBPα binding sites (-1216 to -735) and a GC box with consensus binding sites for c-Myc, E2F1, and p300-associated protein complex (-633 to -1). Age-related changes in NS expression correlated positively with the expression of c-Myc, E2F1, and p300, and negatively with that of C/EBPα and C/EBPβ. PHx upregulated NS expression at 1d, coinciding with an increase in E2F1 and a decrease in C/EBPα. C/EBPα bound to the consensus sequences found in the NS promoter in vitro and in vivo, inhibited its transactivational activity in a binding site-dependent manner, and decreased the expression of endogenous NS in Hep3B cells. In vivo activation of C/EBPα by the S193D mutation resulted in a 4th-day post-PHx reduction of NS, a feature shared by 16-m/o livers. Finally, C/EBPα knockdown increased its expression in aged (24-m/o) livers under both baseline and regeneration conditions. This study reports the C/EBPα suppression of NS expression in aged livers, providing a new perspective on the mechanistic orchestration of tissue homeostasis in aging. [ABSTRACT FROM AUTHOR]

Introduction: Si-Ni-San (SNS), a traditional Chinese medicine, is effective in treating liver fibrosis with an unclear mechanism. Although disturbance of intestinal flora and the subsequent secretion of short-chain fatty acids (SCFAs) is suggested to be involved in the progression of liver fibrosis, whether SNS produces the anti-fibrosis effect through the regulation of intestinal flora and SCFAs remains unclear. Methods: In the current study, carbon tetrachloride (CCl4)-treated mice were dosed with SNS to examine the anti-fibrotic effects and the involved mechanism. Biochemical parameters, histological staining, and analyses of fibrotic gene expression were used to evaluate the anti-fibrotic effect of SNS, while intestinal flora and SCFA content were determined by 16S rRNA and LC-MS to evaluate the mechanism. Results: In vivo results showed that SNS improved liver function, reduced hepatocyte apoptosis and FFAR2/3 expression, and restored intestinal dysbiosis and reduced PA, BA, and IsA levels. In vitro experiments showed that PA, BA, and IsA exacerbated TNF-α-induced HepG2 apoptosis. Notably, the protective effects of SNS were compromised in pseudo-sterile mice. Discussion: In conclusion, our experimental results suggest that the disturbance in intestinal flora results in elevated SCFA levels, which further exacerbates hepatocyte apoptosis in liver fibrosis, while SNS suppresses CCl4-induced liver fibrosis at least partially by reinstating intestinal flora homeostasis and reducing SCFA levels. [ABSTRACT FROM AUTHOR]

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Understanding the liver stem cells (LSCs) holds great promise for new insights into liver diseases and liver regeneration. However, the heterogenicity and plasticity of liver cells have made it controversial. Here, by employing single‐cell RNA‐sequencing technology, transcriptome features of Krt19+ bile duct lineage cells isolated from Krt19CreERT; Rosa26R‐GFP reporter mouse livers are examined. Distinct biliary epithelial cells which include adult LSCs, as well as their downstream hepatocytes and cholangiocytes are identified. Importantly, a novel cell surface LSCs marker, CD63, as well as CD56, which distinguished active and quiescent LSCs are discovered. Cell expansion and bi‐potential differentiation in culture demonstrate the stemness ability of CD63+ cells in vitro. Transplantation and lineage tracing of CD63+ cells confirm their contribution to liver cell mass in vivo upon injury. Moreover, CD63+CD56+ cells are proved to be activated LSCs with vigorous proliferation ability. Further studies confirm that CD63+CD56− quiescent LSCs express VEGFR2 and FGFR1, and they can be activated to proliferation and differentiation through combination of growth factors: VEGF‐A and bFGF. These findings define an authentic adult liver stem cells compartment, make a further understanding of fate regulation on LSCs, and highlight its contribution to liver during pathophysiologic processes. [ABSTRACT FROM AUTHOR]

Background: Primary human hepatocytes (PHHs) are highly valuable for drug-metabolism evaluation, liver disease modeling and hepatocyte transplantation. However, their availability is significantly restricted due to limited donor sources, alongside their constrained proliferation capabilities and reduced functionality when cultured in vitro. To address this challenge, we aimed to develop a novel method to efficiently expand PHHs in vitro without a loss of function. Methods: By mimicking the in vivo liver regeneration route, we developed a two-step strategy involving the de-differentiation/expansion and subsequent maturation of PHHs to generate abundant functional hepatocytes in vitro. Initially, we applied SiPer, a prediction algorithm, to identify candidate small molecules capable of activating liver regenerative transcription factors, thereby formulating a novel hepatic expansion medium to de-differentiate PHHs into proliferative human hepatic progenitor-like cells (ProHPLCs). These ProHPLCs were then re-differentiated into functionally mature hepatocytes using a new hepatocyte maturation condition. Additionally, we investigated the underlying mechanism of PHHs expansion under our new conditions. Results: The novel hepatic expansion medium containing hydrocortisone facilitated the de-differentiation of PHHs into ProHPLCs, which exhibited key hepatic progenitor characteristics and demonstrated a marked increase in proliferation capacity compared to cells cultivated in previously established expansion conditions. Remarkably, these subsequent matured hepatocytes rivaled PHHs in terms of transcriptome profiles, drug metabolizing activities and in vivo engraftment capabilities. Importantly, our findings suggest that the enhanced expansion of PHHs by hydrocortisone may be mediated through the PPARα signaling pathway and regenerative transcription factors. Conclusions: This study presents a two-step strategy that initially induces PHHs into a proliferative state (ProHPLCs) to ensure sufficient cell quantity, followed by the maturation of ProHPLCs into fully functional hepatocytes to guarantee optimal cell quality. This approach offers a promising means of producing large numbers of seeding cells for hepatocyte-based applications. [ABSTRACT FROM AUTHOR]

This document is a data report on gene expression after hepatic portal vein ligation (PVL) in rats. It discusses the increasing incidence of primary liver cancer and the surgical interventions available. The report focuses on the technique of portal vein ligation in rats and its comparison to portal vein embolization. It also discusses the role of non-coding RNAs, particularly microRNAs, in liver biology and the potential for therapeutic targeting in liver diseases and surgical interventions. The document provides sequencing statistics for small RNA samples obtained from a study on hepatic perfusion and function in healthy and venous-ligated livers. The dataset is valuable for understanding the relationship between hepatic perfusion and gene expression, particularly for non-coding RNAs. The animal study was conducted ethically and the research was funded by the DFG within the Research Unit Programme FOR 5151 QuaLiPerF. The authors declare no conflicts of interest, except for one author who was employed by Oncgnostics GmbH. The claims expressed in the article are solely those of the authors and do not necessarily represent their affiliated organizations or the publisher. [Extracted from the article]

Introduction: Acute liver failure (ALF) is one of the emergency illnesses Bone marrow mesenchymal stem cell derived (BMMSC) exosomes are broadly used in recovering medicine. Aim of the Work: Demonstration of the role of BM-MSC exosomes in hepatic regeneration after acute liver damage induced by carbon tetrachloride model in adult male albino rats. Materials and Methods: 55 adult male albino rats were separated into three groups: Group I (control), group II [given a single intraperitoneal injection (0.05 ml/kg) of carbon tetrachloride (CCl4) and group III [given a single tail vein injection of 50 μg of BM-MSC exosomes in 100 μl phosphate buffered saline 24 hours post-CCl4]. The rats were sacrificed after 7 and 14 days. Histological examination of liver tissue was performed with biochemical analysis of AST and ALT. Results: Group II revealed altered hepatic architecture with focal cellular access. Congestion and widening of portal and central veins. Sinusoids appeared disorganized and obliterated. Most hepatocytes had deeply acidophilic cytoplasm with condensed nuclei, while others were seen with pyknotic nuclei and vacuolation in cytoplasm. Collagen fibers were significantly increased. Examination by electron microscope showed hepatocytes with irregular heterochromatic nuclei and rarified cytoplasm with plenty of lipid droplets. Mitochondria decreased in numbers and sizes. Hepatic stellate cells were devoid of lipid droplets. Blood sinusoids showed multiple Kupffer cells. ALT & AST levels were significantly elevated. The exosomes treated rats showed improvement of the previously mentioned histological and biochemical changes. Conclusion: Failure of liver regeneration and repair through 2 weeks after CCl4 induced toxicity. A single dose of bone marrow mesenchymal stem cells derived exosomes improved the hepatic regeneration after acute injury induced by CCl4. [ABSTRACT FROM AUTHOR]

Improving liver regeneration (LR) remains a medical issue, and there is currently a lack of safe and effective drugs for LR. Rhizoma Dioscoreae (SanYak, SY) is a traditional Chinese medicine. However, the underlying action mechanism of SY treatment for LR is yet to be fully elucidated. To explore the mechanism by which SY affects LR, we have conducted a series of methods for network pharmacological analysis, molecular docking, and in vivo experimental validation in mice. Overall, 9 compounds and 30 predicted target genes of SY were found to be associated with the therapeutic effects of LR. Compared with the model group, hematoxylin and eosin staining revealed that the mice with preoperative drug intervention possessed fewer postoperative hepatocyte bubbles and relatively regular morphology. Furthermore, the serum alanine transaminase and aspartate aminotransferase levels were reduced, immunohistochemistry revealed elevated proliferating cell nuclear antigen positivity rate, and Western blotting demonstrated that the phospho-protein kinase B (AKT)/AKT ratio was downregulated and that vascular endothelial growth factor A (VEGFA) expression levels were upregulated. This study explored dioscin, the main active ingredient of SY, and its potential therapeutic effects on LR. It repairs damaged liver following surgery and promotes liver cell proliferation. The action mechanism comprises reducing AKT phosphorylation levels and upregulating VEGFA expression levels. Thus, this study provides a new direction for further research on the mechanism of SY promoting LR. [ABSTRACT FROM AUTHOR]

Background: Exercise can promote sustainable protection against cold and warm liver ischemia–reperfusion injury (IRI) and tumor metastases. We have shown that this protection is by the induction of hepatic mitochondrial biogenesis pathway. In this study, we hypothesize that ZLN005, a PGC-1α activator, can be utilized as an alternative therapeutic strategy. Methods: Eight-week-old mice were pretreated with ZLN005 and subjected to liver warm IRI. To establish a liver metastatic model, MC38 cancer cells (1 × 106) were injected into the spleen, followed by splenectomy and liver IRI. Results: ZLN005-pretreated mice showed a significant decrease in IRI-induced tissue injury as measured by serum ALT/AST/LDH levels and tissue necrosis. ZLN005 pretreatment decreased ROS generation and cell apoptosis at the site of injury, with a significant decrease in serum pro-inflammatory cytokines, innate immune cells infiltration, and intrahepatic neutrophil extracellular trap (NET) formation. Moreover, mitochondrial mass was significantly upregulated in hepatocytes and maintained after IRI. This was confirmed in murine and human hepatocytes treated with ZLN005 in vitro under normoxic and hypoxic conditions. Additionally, ZLN005 preconditioning significantly attenuated tumor burden and increased the percentage of intratumoral cytotoxic T cells. Conclusions: Our study highlights the effective protection of ZLN005 pretreatment as a therapeutic alternative in terms of acute liver injury and tumor metastases. [ABSTRACT FROM AUTHOR]

Platelets play a crucial role in tissue regeneration, and their involvement in liver regeneration is well‐established. However, the specific contribution of platelet‐derived Transforming Growth Factor Beta 1 (TGFβ1) to liver regeneration remains unexplored. This study investigated the role of platelet‐derived TGFβ1 in initiating liver regeneration following 2/3 liver resection. Using platelet‐specific TGFβ1 knockout (Plt.TGFβ1 KO) mice and wild‐type littermates (Plt.TGFβ1 WT) as controls, the study assessed circulating levels and hepatic gene expression of TGFβ1, Platelet Factor 4 (PF4), and Thrombopoietin (TPO) at early time points post‐hepatectomy (post‐PHx). Hepatocyte proliferation was quantified through Ki67 staining and PCNA expression in total liver lysates at various intervals, and phosphohistone‐H3 (PHH3) staining was employed to mark mitotic cells. Circulating levels of hepatic mitogens, Hepatocyte Growth Factor (HGF), and Interleukin‐6 (IL6) were also assessed. Results revealed that platelet‐TGFβ1 deficiency significantly reduced total plasma TGFβ1 levels at 5 h post‐PHx in Plt.TGFβ1 KO mice compared to controls. While circulating PF4 levels, liver platelet recruitment and activation appeared normal at early time points, Plt.TGFβ1 KO mice showed more stable circulating platelet numbers with higher numbers at 48 h post‐PHx. Notably, hepatocyte proliferation was significantly reduced in Plt.TGFβ1 KO mice. The results show that a lack of TGFβ1 in platelets leads to an unbalanced expression of IL6 in the liver and to strongly increased HGF levels 48 h after liver resection, and yet liver regeneration remains reduced. The study identifies platelet‐TGFβ1 as a regulator of hepatocyte proliferation and platelet homeostasis in the early stages of liver regeneration. [ABSTRACT FROM AUTHOR]

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

Understanding the endogenous mechanism of adaptive response to drug‐induced liver injury (arDILI) may discover innovative strategies to manage DILI. To gain mechanistic insight into arDILI, we investigated exosomal miRNAs in the adaptive response to toosendanin‐induced liver injury (TILI) of mice. Exosomal miR‐106b‐5p was identified as a specific regulator of arDILI by comprehensive miRNA profiling. Outstandingly, miR‐106b‐5p agomir treatment alleviated TILI and other DILI by inhibiting apoptosis and promoting hepatocyte proliferation. Conversely, antagomir treatments had opposite effects, indicating that miR‐106b‐5p protects mice from liver injury. Injured hepatocytes released miR‐106b‐5p‐enriched exosomes taken up by surrounding hepatocytes. Vim (encodes vimentin) was identified as an important target of miR‐106b‐5p by dual luciferase reporter and siRNA assays. Furthermore, single‐cell RNA‐sequencing analysis of toosendanin‐injured mouse liver revealed a cluster of Vim+ hepatocytes; nonetheless declined following miR‐106b‐5p cotreatment. More importantly, Vim knockout protected mice from acetaminophen poisoning and TILI. In the clinic, serum miR‐106b‐5p expression levels correlated with the severity of DILI. Indeed, liver biopsies of clinical cases exposed to different DILI causing drugs revealed marked vimentin expression among harmed hepatocytes, confirming clinical relevance. Together, we report mechanisms of arDILI whereby miR‐106b‐5p safeguards restorative tissue repair by targeting vimentin. [ABSTRACT FROM AUTHOR]

Background/Aim: The liver effectively restores both size and function following partial hepatectomy (PHx). Angiogenesis is crucial for the repair and regeneration of liver tissue post-PHx. Calcitonin gene-related peptide (CGRP) released from sensory nerves and its receptor—receptor activity-modifying protein 1 (RAMP1) are involved in angiogenesis. This study aimed to assess the role of RAMP1 signaling in angiogenesis during liver regeneration following PHx. Materials and Methods: RAMP1 deficient (RAMP1–/–) and wild-type (WT) mice were subjected to PHx. Results: RAMP1–/– mice demonstrated delayed liver regeneration, indicated by lower liver-to-body weight ratios compared to WT mice. This was associated with lower levels of Ki67+ hepatocytes and hepatic trophic growth factors. Additionally, RAMP1–/– mice exhibited lower levels of endothelial cell markers, including CD31, compared to WT mice. This reduction was associated with reduced levels of vascular endothelial growth factor (VEGF)-C, VEGF-D, and VEGF receptor 3 (VEGFR3). In WT mice with PHx, the administration of a VEGFR3 inhibitor reduced the liver-to-body weight ratio, Ki67+ hepatocytes, and VEGFC/ VEGFR3 expression levels in the liver compared to those in the vehicle-treated group. Conclusion: The deletion of RAMP1 signaling suppresses liver regeneration and angiogenesis through VEGFR3. Specific activation of RAMP1 signaling may represent a potential therapeutic strategy for liver regeneration following PHx. [ABSTRACT FROM AUTHOR]

Liver regeneration (LR) is a complex process encompassing three distinct phases: priming, proliferation phase and restoration, all influenced by various regulatory factors. After liver damage or partial resection, the liver tissue demonstrates remarkable restorative capacity, driven by cellular proliferation and repair mechanisms. The essential roles of non-coding RNAs (ncRNAs), predominantly microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNA (circRNA), in regulating LR have been vastly studied. Additionally, the impact of ncRNAs on LR and their abnormal expression profiles during this process have been extensively documented. Mechanistic investigations have revealed that ncRNAs interact with genes involved in proliferation to regulate hepatocyte proliferation, apoptosis and differentiation, along with liver progenitor cell proliferation and migration. Given the significant role of ncRNAs in LR, an in-depth exploration of their involvement in the liver's self-repair capacity can reveal promising therapeutic strategies for LR and liver-related diseases. Moreover, understanding the unique regenerative potential of the adult liver and the mechanisms and regulatory factors of ncRNAs in LR are crucial for improving current treatment strategies and exploring new therapeutic approaches for various liver-related diseases. This review provides a brief overview of the LR process and the ncRNA expression profiles during this process. Furthermore, we also elaborate on the specific molecular mechanisms through which multiple key ncRNAs regulate the LR process. Finally, based on the expression characteristics of ncRNAs and their interactions with proliferation-associated genes, we explore their potential clinical application, such as developing predictive indicators reflecting liver regenerative activity and manipulating LR processes for therapeutic purposes.

Abstract Tissue-derived extracellular vesicles (EVs) are emerging as pivotal players to maintain organ homeostasis, which show promise as a next-generation candidate for medical use with extensive source. However, the detailed function and therapeutic potential of tissue EVs remain insufficiently studied. Here, through bulk and single-cell RNA sequencing analyses combined with ultrastructural tissue examinations, we first reveal that in situ liver tissue EVs (LT-EVs) contribute to the intricate liver regenerative process after partial hepatectomy (PHx), and that hepatocytes are the primary source of tissue EVs in the regenerating liver. Nanoscale and proteomic profiling further identify that the hepatocyte-specific tissue EVs (Hep-EVs) are strengthened to release with carrying proliferative messages after PHx. Moreover, targeted inhibition of Hep-EV release via AAV-shRab27a in vivo confirms that Hep-EVs are required to orchestrate liver regeneration. Mechanistically, Hep-EVs from the regenerating liver reciprocally stimulate hepatocyte proliferation by promoting cell cycle progression through Cyclin-dependent kinase 1 (Cdk1) activity. Notably, supplementing with Hep-EVs from the regenerating liver demonstrates translational potential and ameliorates insufficient liver regeneration. This study provides a functional and mechanistic framework showing that the release of regenerative Hep-EVs governs rapid liver regeneration, thereby enriching our understanding of physiological and endogenous tissue EVs in organ regeneration and therapy.

Abstract The influence of liver fibrosis on the rate of liver regeneration and complications following ALPPS has yet to be fully understood. This study aimed to scrutinize the effects of liver fibrosis on the postoperative complications, and prognosis subsequent to ALPPS. Clinical data were collected from patients with primary liver cancer who underwent ALPPS at Peking Union Medical College Hospital between May 2014 and October 2022. The degree of liver fibrosis was assessed using haematoxylin–eosin staining and Sirius red staining. This study encompassed thirty patients who underwent ALPPS for primary liver cancer, and there were 23 patients with hepatocellular carcinoma, 5 with cholangiocarcinoma, and 2 with combined hepatocellular-cholangiocarcinoma. The impact of severe liver fibrosis on the rate of liver regeneration was not statistically significant (P = 0.892). All patients with severe complications belonged to the severe liver fibrosis group. Severe liver fibrosis exhibited a significant association with 90 days mortality (P = 0.014) and overall survival (P = 0.012). Severe liver fibrosis emerges as a crucial risk factor for liver failure and perioperative mortality following the second step of ALPPS. Preoperative liver function impairment is an important predictive factor for postoperative liver failure.

Abstract Liver fibrosis is a hallmark of chronic liver disease which could lead to liver cirrhosis or liver cancer. However, there is currently lack of a direct treatment for liver fibrosis. Boiling histotripsy (BH) is an emerging non-invasive high-intensity focused ultrasound technique that can be employed to mechanically destruct solid tumour at the focus via acoustic cavitation without significant adverse effect on surrounding tissue. Here, we investigated whether BH can mechanically fractionate liver fibrotic tissue thereby exhibiting an anti-fibrotic effect in an animal model of liver fibrosis. BH-treated penumbra and its identical lobe showed reduced liver fibrosis, accompanied by increased hepatocyte specific marker expression, compared to the BH-untreated lobe. Furthermore, BH treatment improved serological liver function markers without notable adverse effects. The ability of BH to reduce fibrosis and promote liver regeneration in liver fibrotic tissue suggests that BH could potentially be an effective and reliable therapeutic approach against liver fibrosis.

Fenofibrate, a peroxisome proliferator-activated receptor α (PPARα) agonist, is widely prescribed for hyperlipidemia management. Recent studies also showed that it has therapeutic potential in various liver diseases. However, its effects on hepatomegaly and liver regeneration and the involved mechanisms remain unclear. Here, the study showed that fenofibrate significantly promoted liver enlargement and regeneration post-partial hepatectomy in mice, which was dependent on hepatocyte-expressed PPARα. Yes-associated protein (YAP) is pivotal in manipulating liver growth and regeneration. We further identified that fenofibrate activated YAP signaling by suppressing its K48-linked ubiquitination, promoting its K63-linked ubiquitination, and enhancing the interaction and transcriptional activity of the YAP–TEAD complex. Pharmacological inhibition of YAP–TEAD interaction using verteporfin or suppression of YAP using AAV Yap shRNA in mice significantly attenuated fenofibrate-induced hepatomegaly. Other factors, such as MYC, KRT23, RAS, and RHOA, might also participate in fenofibrate-promoted hepatomegaly and liver regeneration. These studies demonstrate that fenofibrate-promoted liver enlargement and regeneration are PPARα-dependent and partially through activating the YAP signaling, with clinical implications of fenofibrate as a novel therapeutic agent for promoting liver regeneration.

Extracellular vesicles (EVs) have gainedsignificant attention due totheir crucialroles invarious biological systems. This review aims to explore the functions of EVs in both in physiological and pathological states of the liver, with a specific focus on the potential mechanisms and concrete evidence of EVs in liver regeneration processes. The review begins by emphasizing the importance of EVs in maintaining liver health and their involvement in different pathological conditions, starting from the liver's own EVs. Reviewing the role of EVs in liver diseases to reveal the impact of EVs in pathological processes (e.g., hepatitis, liver fibrosis, and cirrhosis) and elucidate their signaling functions at the molecular level. Subsequently, the work concentrates on the functions of EVs in liver regeneration, revealing their key role in repair and regeneration following liver injury by carrying growth factors, nucleic acids, and other bioactive molecules. This part not only theoretically clarifies the mechanisms of EVs in liver regeneration but also experimentally demonstrates their role in promoting liver cell proliferation, inhibiting apoptosis, regulating immune responses, and fostering angiogenesis, laying the groundwork for future clinical applications. Moreover, this work provides a comprehensive analysis of the challenges faced by existing EV-based therapies in liver regeneration and offers prospects for future research directions. It highlights that despite the tremendous potential of EVs in treating liver diseases, there are still technical challenges (e.g., EV isolation and purification, dosage control, and targeted delivery). To overcome these challenges, the review suggests improvements to current technologies and the development of new methods to realize the clinical application of EVs in treating liver diseases.

The regenerative capability of the liver is remarkable, but further research is required to understand the role that neutrophils play in this process. In the present study, we reanalyzed single‐cell RNA sequencing data from a mouse partial hepatectomy (PH) model to track the transcriptional changes in hepatocytes and non‐parenchymal cells. Notably, we unraveled the regenerative capacity of hepatocytes at diverse temporal points after PH, unveiling the contributions of three distinct zones in the liver regeneration process. In addition, we observed that the depletion of neutrophils reduced the survival and liver volume after PH, confirming the important role of neutrophils in liver regeneration. CellChat analysis revealed an intricate crosstalk between neutrophils and macrophages promoting liver regeneration and, using weighted gene correlation network analysis, we identified the most significant genetic module associated with liver regeneration. Our study found that hepatocytes in the periportal zone of the liver are more active than in other zones, suggesting that the crosstalk between neutrophils and macrophages might be a potential target for liver regeneration treatment.

Tissue-derived extracellular vesicles (EVs) are emerging as pivotal players to maintain organ homeostasis, which show promise as a next-generation candidate for medical use with extensive source. However, the detailed function and therapeutic potential of tissue EVs remain insufficiently studied. Here, through bulk and single-cell RNA sequencing analyses combined with ultrastructural tissue examinations, we first reveal that in situ liver tissue EVs (LT-EVs) contribute to the intricate liver regenerative process after partial hepatectomy (PHx), and that hepatocytes are the primary source of tissue EVs in the regenerating liver. Nanoscale and proteomic profiling further identify that the hepatocyte-specific tissue EVs (Hep-EVs) are strengthened to release with carrying proliferative messages after PHx. Moreover, targeted inhibition of Hep-EV release via AAV-shRab27a in vivo confirms that Hep-EVs are required to orchestrate liver regeneration. Mechanistically, Hep-EVs from the regenerating liver reciprocally stimulate hepatocyte proliferation by promoting cell cycle progression through Cyclin-dependent kinase 1 (Cdk1) activity. Notably, supplementing with Hep-EVs from the regenerating liver demonstrates translational potential and ameliorates insufficient liver regeneration. This study provides a functional and mechanistic framework showing that the release of regenerative Hep-EVs governs rapid liver regeneration, thereby enriching our understanding of physiological and endogenous tissue EVs in organ regeneration and therapy. [ABSTRACT FROM AUTHOR]

Lack of liver regenerative capacity is the primary cause of hepatic failure and even mortality in patients undergoing hepatectomy, with no effective intervention strategies currently available. Therefore, identifying efficacious interventions to enhance liver regeneration is pivotal for optimizing clinical outcomes. Recent studies have demonstrated that vagotomy exerts an inhibitory effect on liver regeneration following partial hepatectomy, thereby substantiating the pivotal role played by the vagus nerve in the process of liver regeneration. In recent years, electroacupuncture (EA) has emerged as a non‐invasive technique for stimulating the vagus nerve. However, EA on hepatic regeneration remains uncertain. In this study, a 70% partial hepatectomy (PH) mouse model is utilized to investigate the effects of EA on acute liver regeneration and elucidate its underlying molecular mechanisms. It is observed that EA at ST36 acutely activated cholinergic neurons in the dorsal motor nucleus of the vagus nerve (DMV), resulting in increased release of acetylcholine from hepatic vagal nerve endings and subsequent activation of IL‐6 signaling in liver macrophages. Ultimately, these events promoted hepatocyte proliferation and facilitated liver regeneration. These findings provide insights into the fundamental brain‐liver axis mechanism through which EA promotes liver regeneration, offering a novel therapeutic approach for post‐hepatectomy liver regeneration disorders. [ABSTRACT FROM AUTHOR]

Hepatic ischemia‐reperfusion injury (HIRI) is a prevalent issue during liver resection and transplantation, with currently no cure or FDA‐approved therapy. A promising drug, Cyclosporin A (CsA), ameliorates HIRI by maintaining mitochondrial homeostasis but has systemic side effects due to its low bioavailability and high dosage requirements. This study introduces a biomimetic CsA delivery system that directly targets hepatic lesions using mesenchymal stem cell (MSC) membrane‐camouflaged liposomes. These hybrid nanovesicles (NVs), leveraging MSC‐derived proteins, demonstrate efficient inflammatory chemotaxis, transendothelial migration, and drug‐loading capacity. In a HIRI mouse model, the biomimetic NVs accumulated at liver injury sites entered hepatocytes, and significantly reduced liver damage and restore function using only one‐tenth of the CsA dose typically required. Proteomic analysis verifies the protection mechanism, which includes reactive oxygen species inhibition, preservation of mitochondrial integrity, and reduced cellular apoptosis, suggesting potential for this biomimetic strategy in HIRI intervention. [ABSTRACT FROM AUTHOR]

Background and aim: Bone marrow stem cells (BM-SCs) and their progeny play a central role in tissue repair and regeneration. In patients with chronic liver failure, bone marrow (BM) reserve is severally compromised and they showed marked defects in the resolution of injury and infection, leading to liver failure and the onset of decompensation. Whether BM failure is the cause or consequence of liver failure during cirrhosis is not known. In this study, we aimed to determine the underlying relationship between BM failure and regeneration failure in cirrhosis. Methodology: C57Bl/6(J) mice were used to develop chronic liver injury through intra-peritoneal administration of carbon tetrachloride (CCl4) for 15 weeks (0.1- 0.5 ml/kg). Animals were sacrificed to study the transition of cirrhosis and BM defects. To restore the BM-SC reserve; healthy BM cells were infused via intra- BM infusion and assessed for changes in liver injury, regeneration, and BMSC reserve. Results: Using a CCl4-induced animal - model of cirrhosis, we showed the loss of BM-SCs reserve occurred before regeneration failure and the onset of nonacute decompensation. Intra-BM infusion of healthy BM cells induced the repopulation of native hematopoietic stem cells (HSCs) in cirrhotic BM. Restoring BM-HSCs reserve augments liver macrophage-mediated clearance of infection and inflammation dampens neutrophil-mediated inflammation, accelerates fibrosis regression, enhances hepatocyte proliferation, and delays the onset of non-acute decompensation. Conclusion: These findings suggest that loss of BM-HSCs reserve underlies the compromised innate immune function of the liver, drives regeneration failure, and the onset of non-acute decompensation. We further provide the proof-ofconcept that rejuvenating BM-HSC reserve can serve as a potential therapeutic approach for preventing regeneration failure and transition to decompensated cirrhosis. [ABSTRACT FROM AUTHOR]

Liver fibrosis is a chronic pathological condition lacking specific clinical treatments. Stem cells, with notable potential in regenerative medicine, offer promise in treating liver fibrosis. However, stem cell therapy is hindered by potential immunological rejection, carcinogenesis risk, efficacy variation, and high cost. Stem cell secretome‐based cell‐free therapy offers potential solutions to address these challenges, but it is limited by low delivery efficiency and rapid clearance. Herein, an innovative approach for in situ implantation of smart microneedle (MN) arrays enabling precisely controlled delivery of multiple therapeutic agents directly into fibrotic liver tissues is developed. By integrating cell‐free and platinum‐based nanocatalytic combination therapy, the MN arrays can deactivate hepatic stellate cells. Moreover, they promote excessive extracellular matrix degradation by more than 75%, approaching normal levels. Additionally, the smart MN arrays can provide hepatocyte protection while reducing inflammation levels by ≈70–90%. They can also exhibit remarkable capability in scavenging almost 100% of reactive oxygen species and alleviating hypoxia. Ultimately, this treatment strategy can effectively restrain fibrosis progression. The comprehensive in vitro and in vivo experiments, supplemented by proteome and transcriptome analyses, substantiate the effectiveness of the approach in treating liver fibrosis, holding immense promise for clinical applications. [ABSTRACT FROM AUTHOR]

Liver fibrosis progressing to cirrhosis is a major risk factor for liver cancer, impacting surgical treatment and survival. Our study focuses on the role of extracellular nicotinamide adenine dinucleotide (eNAD+) in liver fibrosis, analyzing liver disease patients undergoing surgery. Additionally, we explore NAD+'s therapeutic potential in a mouse model of extended liver resection and in vitro using 3D hepatocyte spheroids. eNAD+ correlated with aspartate transaminase (AST) and bilirubin after liver resection (AST: r = 0.2828, p = 0.0087; Bilirubin: r = 0.2584, p = 0.0176). Concordantly, post-hepatectomy liver failure (PHLF) was associated with higher eNAD+ peaks (n = 10; p = 0.0063). Post-operative eNAD+ levels decreased significantly (p < 0.05), but in advanced stages of liver fibrosis or cirrhosis, this decline not only diminished but actually showed a trend towards an increase. The expression of NAD+ biosynthesis rate-limiting enzymes, nicotinamide phosphoribosyltransferase (NAMPT) and nicotinamide mononucleotide adenylyltransferase 3 (NMNAT3), were upregulated significantly in the liver tissue of patients with higher liver fibrosis stages (p < 0.0001). Finally, the administration of NAD+ in a 3D hepatocyte spheroid model rescued hepatocytes from TNFalpha-induced cell death and improved viability (p < 0.0001). In a mouse model of extended liver resection, NAD+ treatment significantly improved survival (p = 0.0158) and liver regeneration (p = 0.0186). Our findings reveal that eNAD+ was upregulated in PHLF, and rate-limiting enzymes of NAD+ biosynthesis demonstrated higher expressions under liver fibrosis. Further, eNAD+ administration improved survival after extended liver resection in mice and enhanced hepatocyte viability in vitro. These insights may offer a potential target for future therapies. An analysis on liver disease patients suggests that extracellular Nicotinamide adenine dinucleotide (eNAD + ) correlates with liver fibrosis and post-hepatectomy liver failure, with NAD+ administration improving survival and liver regeneration in mice and hepatocyte viability in vitro. [ABSTRACT FROM AUTHOR]

Background: Hepatocyte nuclear factor 4 alpha (HNF4α) is the master regulator of hepatic differentiation. Recent studies have also revealed the role of HNF4α in hepatocyte proliferation via negatively regulating the expression of protomitogenic genes, including cMyc. Here, we aimed to study the interaction between HNF4α-cMyc during liver regeneration after partial hepatectomy (PHX). Methods: Wild-type (WT), hepatocyte-specific knockout of HNF4α (HNF4α-KO), cMyc (cMyc-KO), and HNF4α-cMyc double knockout (DKO) mice were subjected to PHX to induce liver regeneration. Blood and liver tissue samples were collected at 0h, 24h, 48h, 7D, and 14D after PHX for further analysis. Results: WT, HNF4α-KO, cMyc-KO and DKO mice regained liver weight by 14 days after PHX. The deletion of cMyc did not affect liver regeneration, which was similar to the WT mice. WT and cMyc-KO mice started regaining liver weight as early as 24 hours after PHX, with a peak proliferation response at 48 hours after PHX. HNF4α-KO and DKO showed a delayed response with liver weight increase by day 7 after PHX. The overall hepatocyte proliferation response by DKO mice following PHX was lower than that of other genotypes. Interestingly, the surviving HNF4α-KO and DKO mice showed re-expression of HNF4α at mRNA and protein levels on day 14 after PHX. This was accompanied by a significant increase in the expression of Krt19 and Epcam, hepatic progenitor cell markers, in the DKO mice on day 14 after PHX. Conclusion: These data indicate that, in the absence of HNF4α, cMyc contributes to hepatocyte-driven proliferation to compensate for the lost tissue mass. Furthermore, in the absence of both HNF4α and cMyc, HPC-driven proliferation occurs to support liver regeneration. [ABSTRACT FROM AUTHOR]

In order to explore the regulatory effects of metformin on the proliferation, migration and TGF-β1/Smads signaling pathway of human liver cancer cells, human liver cancer MHCC97H cells were cultured in vitro. They were divided into control group (no intervention), 1.25, 2.50, 5.00 mmol/L metformin group and inhibitor group (5.00 mmol/L metformin +10 μmol/L LY2109761). In this study, the cell viability of 5.00 mmol/L metformin group was close to 50%, hence 5.00 mmol/L metformin was selected as the optimal concentration. Cell counting kit-8 (CCK-8), 5-acetylidene-2' deoxyuracil riboside (EdU), Transwell chamber, real-time fluorescence quantitative PCR (RT-qPCR) and Western blot were used to analyze the proliferation activity, proliferation rate, migration ability and expression levels of related factors of human hepatocellular carcinoma MHCC97H cells. Compared with the control group, the proliferation activity and proliferation rate of 2.50 and 5.00 mmol/L metformin groups and inhibitor groups decreased (P<0.05). The cell migration number, TGF-β1 and p-Smad3 protein expression levels, N-cadherin, vimentin and fibronectin (FN) mRNA and protein expression levels of 1.25, 2.50 and 5.00 mmol/L metformin groups and inhibitor group decreased compared with the control group. The expression level of p-Smad7 protein, E-cadherin mRNA and protein significantly increased, and the changes were more significant with the increase of concentration (P<0.05). Compared with 5.00 mmol/L metformin group, the addition of inhibitors in the inhibitor group made the changes of all indexes more significant (P<0.05). The inhibition of metformin on the proliferation, migration and epithelial-mesenchymal transformation (EMT) of MHCC97H cells of human liver cancer depends on the inhibition of TGF-β1/Smads pathway, which provides a reference for the study of liver cancer. [ABSTRACT FROM AUTHOR]

The liver has the great ability to regenerate after partial resection or injury, and the mechanisms underlying liver regeneration have been extensively investigated. Interestingly, acute liver injuries triggered by various etiologies are associated with the formation of necrotic lesions, and such necrotic lesions are also rapidly resolved. However, how necrotic liver lesions are repaired has not been carefully investigated until recently. In this review, we briefly summarize the spatiotemporal process of necrotic liver lesion resolution in several liver injury models including immune-mediated liver injury and drug-induced liver injury. The roles of liver nonparenchymal cells and infiltrating immune cells in controlling necrotic liver lesion resolution are discussed, which may help identify potential therapies for acute liver injury and failure. [ABSTRACT FROM AUTHOR]

The liver is a remarkable organ that can regenerate in response to injury. Depending on the extent of injury, the liver can undergo compensatory hyperplasia or fibrosis. Despite decades of research, the molecular mechanisms underlying these processes are poorly understood. Here, we developed a new model to study liver regeneration based on cryoinjury. To visualise liver regeneration at cellular resolution, we adapted the CUBIC tissue-clearing approach. Hepatic cryoinjury induced a localised necrotic and apoptotic lesion characterised by inflammation and infiltration of innate immune cells. After this initial phase, we observed fibrosis, which resolved as regeneration re-established homeostasis in 30 days. Importantly, this approach enables the comparison of healthy and injured parenchyma within an individual animal, providing unique advantages to previous models. In summary, the hepatic cryoinjury model provides a fast and reproducible method for studying the cellular and molecular pathways underpinning fibrosis and liver regeneration. [ABSTRACT FROM AUTHOR]

Liver fibrosis typically develops as a result of chronic liver injury, which involves inflammatory and regenerative processes. The triggering receptor expressed on myeloid cells 2 (TREM2), predominantly expressing in hepatic non-parenchymal cells, plays a crucial role in regulating the function of macrophages. However, its mechanism in liver fibrosis remains poorly defined. Experimental liver fibrosis models in wild type and TREM2−/− mice, and in vitro studies with AML-12 cells and Raw264.7 cells were conducted. The expression of TREM2 and related molecular mechanism were evaluated by using samples from patients with liver fibrosis. We demonstrated that TREM2 was upregulated in murine model with liver fibrosis. Mice lacking TREM2 exhibited reduced phagocytosis activity in macrophages following carbon tetrachloride (CCl 4) intoxication. As a result, there was an increased accumulation of necrotic apoptotic hepatocytes. Additionally, TREM2 knockout aggravated the release of mitochondrial damage-associated molecular patterns (mito-DAMPs) from dead hepatocytes during CCl 4 exposure, and further promoted the occurrence of macrophage-mediated M1 polarization. Then, TREM2−/− mice showed more serious fibrosis pathological changes. In vitro, the necrotic apoptosis inhibitor GSK872 effectively alleviated the release of mito-DAMPs in AML-12 cells after CCl 4 intoxication, which confirmed that mito-DAMPs originated from dead liver cells. Moreover, direct stimulation of Raw264.7 cells by mito-DAMPs from liver tissue can induce intracellular inflammatory response. More importantly, TREM2 was elevated and inflammatory factors were markedly accumulated surrounding dead cells in the livers of human patients with liver fibrosis. Our study highlights that TREM2 serves as a negative regulator of liver fibrosis, suggesting its potential as a novel therapeutic target. [Display omitted] • TREM2 expression is upregulated in the livers of human patients and murine models with liver fibrosis. • TREM2 mediates the efferocytosis of macrophages in CCl 4 -induced liver fibrosis. • TREM2 protects against the increased release of mito-DAMPs from hepatocytes after CCl 4 intoxication. • Mito-DAMPs from hepatocytes exacerbate macrophage-mediated inflammatory response to experimental liver fibrosis. [ABSTRACT FROM AUTHOR]

Progression of metabolic dysfunction-associated steatites liver disease (MASLD) to steatohepatitis (MASH) is driven by stress-inducing lipids that promote liver inflammation and fibrosis, and MASH can lead to cirrhosis and hepatocellular carcinoma. Previously, we showed coordinated defenses regulated by transcription factors, nuclear factor erythroid 2-related factor-1 (Nrf1) and -2 (Nrf2), protect against hepatic lipid stress. Here, we investigated protective effects of hepatocyte Nrf1 and Nrf2 against MASH-linked liver fibrosis and tumorigenesis. Male and female mice with flox alleles for genes encoding Nrf1 (Nfe2l1), Nrf2 (Nfe2l2), or both were fed a MASH-inducing diet enriched with high fat, fructose, and cholesterol (HFFC) or a control diet for 24–52 weeks. During this period, hepatocyte Nrf1, Nrf2, or combined deficiency for ~7 days, ~7 weeks, and ~35 weeks was induced by administering mice hepatocyte-targeting adeno-associated virus (AAV) expressing Cre recombinase. The effects on MASH, markers of liver fibrosis and proliferation, and liver tumorigenesis were compared to control mice receiving AAV-expressing green fluorescent protein. Also, to assess the impact of Nrf1 and Nrf2 induction on liver fibrosis, HFFC diet-fed C57bl/6J mice received weekly injections of carbon tetrachloride, and from week 16 to 24, mice were treated with the Nrf2-activating drug bardoxolone, hepatocyte overexpression of human NRF1 (hNRF1), or both, and these groups were compared to control. Compared to the control diet, 24-week feeding with the HFFC diet increased bodyweight as well as liver weight, steatosis, and inflammation. It also increased hepatocyte proliferation and a marker of liver damage, p62. Hepatocyte Nrf1 and combined deficiency increased liver steatosis in control diet-fed but not HFFC diet-fed mice, and increased liver inflammation under both diet conditions. Hepatocyte Nrf1 deficiency also increased hepatocyte proliferation, whereas combined deficiency did not, and this also occurred for p62 level in control diet-fed conditions. In 52-week HFFC diet-fed mice, 35 weeks of hepatocyte Nrf1 deficiency, but not combined deficiency, resulted in more liver tumors in male mice, but not in female mice. In contrast, hepatocyte Nrf2 deficiency had no effect on any of these parameters. However, in the 15-week CCL4-exposed and 24-week HFFC diet-fed mice, Nrf2 induction with bardoxolone reduced liver steatosis, inflammation, fibrosis, and proliferation. Induction of hepatic Nrf1 activity with hNRF1 enhanced the effect of bardoxolone on steatosis and may have stimulated liver progenitor cells. Physiologic Nrf1 delays MASLD progression, Nrf2 induction alleviates MASH, and combined enhancement synergistically protects against steatosis and may facilitate liver repair. [ABSTRACT FROM AUTHOR]