Process Of Liver Regeneration Research Articles

Pregnane X receptor activation promotes hematopoiesis during liver regeneration by inducing proliferation of hematopoietic stem and progenitor cells in mice

Liver regeneration is a complex process that involves the recruitment of bone marrow (BM)-derived hematopoietic stem and progenitor cells (HSPCs). Pregnane X receptor (PXR), also known as NR1I2, is an important regulator for liver enlargement and regeneration. However, the role of PXR activation in hematopoiesis during liver regeneration remains unclear. This study investigates the effects of PXR activation on HSPCs and hematopoiesis during liver regeneration, as well as the underlying mechanisms involved. Using a 70% partial hepatectomy (PHx) on C57BL/6 wild-type (WT) and Pxr-null mice, we observed a significant correlation between the changes in HSPCs numbers in BM and the process of liver regeneration. PXR activation significantly increased the population of Lineage- Sca-1+ c-Kit+ (LSK) cells in the BM, which are key HSPCs involved in hematopoiesis. Additionally, PXR activation increased serum levels of thrombopoietin (TPO) and erythropoietin (EPO), factors known to support HSPCs proliferation and hematopoiesis in the process of liver regeneration. PXR activation does not affect the hematopoietic function of normal mice. Furthermore, mice subjected to irradiation or busulfan-induced hematopoietic dysfunction exhibited impaired liver regeneration, which was alleviated by PXR activation. Importantly, in Pxr-null mice, the promotive effects of PXR activation on liver regeneration and increase of HSPCs were markedly diminished. Moreover, liver-specific Pxr silencing using AAV-Pxr shRNA attenuated the PXR activation-mediated liver regeneration and increase in BM LSK cells, confirming the critical role of hepatic PXR in hematopoiesis during liver regeneration. Collectively, these findings reveal that PXR activation promotes HSPCs proliferation and hematopoiesis during liver regeneration, providing new insights into the molecular mechanisms underlying the role of PXR in liver regeneration and hematopoiesis.

Using different zebrafish models to explore liver regeneration

The liver possesses an impressive capability to regenerate following various injuries. Given its profound implications for the treatment of liver diseases, which afflict millions globally, liver regeneration stands as a pivotal area of digestive organ research. Zebrafish (Danio rerio) has emerged as an ideal model organism in regenerative medicine, attributed to their remarkable ability to regenerate tissues and organs, including the liver. Many fantastic studies have been performed to explore the process of liver regeneration using zebrafish, especially the extreme hepatocyte injury model. Biliary-mediated liver regeneration was first discovered in the zebrafish model and then validated in mammalian models and human patients. Considering the notable expansion of biliary epithelial cells in many end-stage liver diseases, the promotion of biliary-mediated liver regeneration might be another way to treat these refractory liver diseases. To date, a comprehensive review discussing the current advancements in zebrafish liver regeneration models is lacking. Therefore, this review aims to investigate the utility of different zebrafish models in exploring liver regeneration, highlighting the genetic and cellular insights gained and discussing the potential translational impact on human health.

Expression of TWEAK/Fn14 axis in the context of metabolic dysfunction associated-fatty liver disease: an approach in liver regeneration

Background: One of the pathways involved in liver regeneration processes is TWEAK/Fn14 (tumor necrosis factor-related weak inducer of apoptosis/fibroblast growth factor-inducible 14), which has been proposed to act directly and selectively on hepatic progenitor cells; however, its role in the regeneration of steatotic liver metabolic dysfunction associated fatty liver disease has not been fully elucidated. Objective: To evaluate the behavior of Fn14 and its ligand TWEAK, as well as cellular stress signals as biochemical cues for possible liver regeneration in MAFLD. Materials and methods: A prospective study was carried out where the behavior of Fn14 and its ligand TWEAK, as well as cellular stress signals were observed as biochemical indications of a possible liver regeneration in a condition of tissue damage caused by excessive lipid accumulation. The expression of TWEAK, Fn14 and heat shock proteins in hepatic steatosis of non-alcoholic origin was assessed using immunohistochemistry and western blotting. Results: The histological classification of the tissues under study corresponded to microvesicular steatosis. We report a high level of expression of heat shock proteins in the cytoplasm. The expression of TWEAK and Fn14 in liver tissue affected by lipid accumulation was localized in the cytoplasm of hepatocytes, showing a higher intensity of reactivity for Fn14 compared to its ligand TWEAK. Conclusion: The expression of TWEAK/Fn14 axis was positive suggesting reactivity of the signaling pathway in metabolic dysfunction associated fatty liver disease.

Hepatocyte-derived tissue extracellular vesicles safeguard liver regeneration and support regenerative therapy

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.

Epigenetic regulation in liver regeneration

The liver is considered unique in its enormous capacity for regeneration and self-repair. In contrast to other regenerative organs (i.e., skin, skeletal muscle, and intestine), whether the adult liver contains a defined department of stem cells is still controversial. In order to compensate for the massive loss of hepatocytes following liver injury, the liver processes a precisely controlled transcriptional reprogram that can trigger cell proliferation and cell-fate switch. Epigenetic events are thought to regulate the organization of chromatin architecture and gene transcription during the liver regenerative process. In this review, we will summarize how changes to the chromatin by epigenetic modifiers are translated into cell fate transitions to restore liver homeostasis during liver regeneration.

Characterization of a model of liver regeneration: Role of hedgehog signaling in experimental hepatic amoebiasis

The development of amoebic liver abscess (ALA) leads to liver necrosis, accompanied by an exacerbated inflammatory response and the formation of multiple granulomas. Adequate management of the infection through the administration of treatment and the timely response of the organ to the damage allows the injury to heal with optimal regeneration without leaving scar tissue, which does not occur in other types of damage such as viral hepatitis that may conducts to fibrosis or cirrhosis. The Hedgehog signaling pathway (Hh) is crucial in the embryonic stage, while in adults it is usually reactivated in response to acute or chronic injuries, regeneration, and wound healing. In this work, we characterized Hh in experimental hepatic amoebiasis model, with the administration of treatment with metronidazole, as well as a pathway inhibitor (cyclopamine), through histological and immunohistochemical analyses including an ultrastructure analysis through transmission electron microscopy. The results showed an increase in the percentage of lesions obtained, a decrease in the presence of newly formed hepatocytes, a generalized inflammatory response, irregular distribution of type I collagen accompanied by the presence of fibroblast-type cells and a decrease in effector cells of this pathway. These results constitute the first evidence of the association of the activation of Hh with the liver regeneration process in experimental amebiasis.

Partial Hepatectomy Promotes the Development of KRASG12V-Induced Hepatocellular Carcinoma in Zebrafish.

The purpose of this study was to investigate the effects of PH on the development of oncogenic krasG12V-induced HCC in zebrafish. The inducible HCC model in Tg(fabp10a:rtTA2s-M2; TRE2:EGFP-krasG12V) zebrafish was used. PH or sham surgery was performed before the induction of oncogenic krasG12V expression in the livers of transgenic zebrafish. Histological analysis was carried out to determine the progression of HCC and other HCC-associated features including hepatocyte proliferation, extracellular matrix production, and local oxidative stress. The similarity between the process of PH-induced liver regeneration and that of krasG12V-induced HCC development was further compared by RNA-Seq analysis. The results show that PH promotes the development of krasG12V-induced HCC in zebrafish possibly through enhancing neutrophil-mediated oxidative stress and promoting the upregulation of s100a1, and the downregulation of ribosome biogenesis.

Neutrophil and macrophage crosstalk might be a potential target for liver regeneration.

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.

EGFR-mediated crosstalk between vascular endothelial cells and hepatocytes promotes Piezo1-dependent liver regeneration

Hepatocyte proliferation is essential for recovering liver function after injury. In liver surgery, the mechanical stimulation induced by hemodynamic changes triggers vascular endothelial cells (VECs) to secrete large amounts of cytokines that enhance hepatocyte proliferation and play a pivotal role in liver regeneration. Piezo1, a critical mechanosensory ion channel, can detect and convert mechanical forces into chemical signals, importing external stimuli into cells and triggering downstream biological effects. However, the precise role of Piezo1 in VECs, especially in terms of mediating liver regeneration, remains unclear. Here, we report on a potential mechanism by which early changes in hepatic portal hemodynamics activate Piezo1 in VECs to promote hepatocyte proliferation during the process of liver regeneration induced by portal vein ligation in rats. In this liver regeneration model, hepatocyte proliferation is mainly distributed in zone 1 and zone 2 of liver lobules at 24–48 h after surgery, while only a small number of Ki67-positive hepatocytes were observed in zone 3. Activation of Piezo1 promotes increased secretion of epiregulin and amphiregulin from VECs via the PKC/ERK1/2 axis, further activating epidermal growth factor receptor (EGFR) and ERK1/2 signals in hepatocytes and promoting proliferation. In addition, cytokines secreted by Piezo1-activated VECs can induce hepatocytes to undergo epithelial–mesenchymal transition. In the liver lobules, the expression of EGFR in hepatocytes of zone 1 and zone 2 is significantly higher than that in zone 3. The EGFR inhibitor gefitinib inhibits liver regeneration by suppressing the proliferation of hepatocytes in the middle zone. Thus, activation of Piezo1 in VECs promotes hepatocyte proliferation, suggesting mechanical stimulation regulates hepatocyte proliferation in zone 1 and zone 2 during portal vein ligation-induced liver regeneration. These data provide a theoretical basis for the regulation of liver regeneration through chemical signals mediated by mechanical stimulation.

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.

Liver Regeneration: The Myth of Prometheus in Modern Medicine A Case Report

Liver regeneration is a complex process of tissue repair and regrowth that takes place in response to liver damage. The liver has the unique ability to regenerate itself after injury, allowing it to recover from a variety of insults including viral infections, drug-induced injury, or surgical resection. The process of liver regeneration involves a coordinated series of cellular and molecular events that ultimately lead to the restoration of liver function. The myth of Prometheus involves liver regeneration. In Greek mythology, Prometheus was a Titan who created humans and gave them fire, which he had stolen from the gods. As punishment for his actions, Zeus ordered Prometheus to be chained to a rock and have his liver eaten by an eagle every day, only for the liver to regenerate overnight and the cycle to repeat endlessly. This myth can be interpreted as a metaphor for the liver's remarkable ability to regenerate itself after injury. The liver has the ability to regenerate lost tissue and can even grow back to its full size and function after being partially removed, such as in a liver transplant or in cases of surgical resection for liver cancer. The story of Prometheus and the regenerating liver has also been used in literature and art to symbolize themes such as endurance, resilience, and the power of the human spirit to overcome adversity. In this case report, Researcher report a patient that was initially presented with liver impairment, Osel Liver Regeneration Protocol was initiated and the subsequent resolution of the patient’s ailment

Effect of platelet automesoconcentrate on the immunological status of experimental animals after liver resection

Objective. To study the indices of cellular and humoral immunity in the blood of rats after liver resection and under conditions of administration of platelet automeso–concentrate.
 Materials and methods. The study was performed on albino Wistar rats weighing 140 – 245 g. Resection of 2/3 of the liver was performed using the method of aseptic removal of its left and central lobes. During the resection, platelet autologous concentrate at a dose of 1 ml/kg was injected into the liver residue. To characterise the cellular and humoral components of immunity, the levels of leukocytes, lymphocytes, the number of total T– and B–lymphocytes, the level of circulating immune complexes, and the content of immunoglobulins of classes G and M were determined.
 Results. In the initial stages after liver resection, a marked leukocytosis was observed, accompanied by an increase in the relative number of basophils, eosinophils, rods and monocytes and a decrease in the level of segmented neutrophils and lymphocytes. The level of lymphocytes decreased at the expense of the T–cell population. Against the background of an increase in the number of B–lymphocytes, there was an increase in the levels of immunoglobulins M, G and circulating immune complexes. The injection of platelet autologous concentrate into the liver residue during resection of this organ stimulated the cellular and humoral immunity, as the studied parameters were higher than those of animals that did not receive platelet autologous concentrate. On the 7th day after partial hepatectomy, the studied parameters approached the control values.
 Conclusions. Components of cellular and humoral immunity can directly or indirectly affect the processes of liver regeneration after liver resection. B–cells after liver resection as antigen–presenting cells can trigger and modulate the immune response, which is enhanced by the introduction of platelet autologous concentrate into the body.

Vitamin A accelerates the process of liver regeneration in the initial stages of Сu - induced fibrosis

Aim: To test the hypothesis about the possible role of vitamin A in normalizing the functional activity of the liver with Cu-induced fibrosis by increasing the regeneration process.
 Materials and methods: Experiments were conducted on 20 sexually mature male Wistar rats, which were divided into 4 groups: a control group that was not exposed to copper sulfate and vitamin A, a group that was at the initial stage of liver fibrosis, which was provided by three consecutive administrations of copper sulfate at a dose of 1 mg/100 g of weight (one series of injections), a group that was at the stage of intensive development of fibrosis (F2), which was carried out by two consecutive series of copper sulfate injections with an interval of 3 days between injections, and a group that received vitamin A three times daily in a dose of 300 IU/100 g of weight between two series of intoxication. Body weight dynamics, relative liver weight, histological changes in liver tissues and the number of binuclear hepatocytes were determined.
 Results: It has been found that animals with Cu-induced liver fibrosis did not gain or lose body weight, and the introduction of vitamin A ensured the restoration of body weight growth, and they slightly lagged behind the control group. In animals with liver fibrosis that received vitamin A, the relative weight of the liver was slightly increased and there were 2 times more binuclear hepatocytes. The structural organization of the liver tissue changed to a minor extent, and to the greatest extent there was an increase in the thickness of the Glisson’s capsule, in which immunocompetent cells were incorporated.
 Conclusions: Vitamin A contributed to the normalization of liver function against the background of the development of fibrosis. The mechanism of normalization can be ensured due to an increase in the number of binuclear hepatocytes, a slight increase in the relative weight of the liver, and was accompanied by an increase in the thickness of the Glisson’s capsule, in which immunocompetent cells were incorporated

Therapeutic strategies to improve liver regeneration after hepatectomy.

Chronic liver disease is one of the most common diseases worldwide, and its prevalence is particularly high among adults aged 40-60 years; it takes a toll on productivity and causes significant economic burden. However, there are still no effective treatments that can fundamentally treat chronic liver disease. Although liver transplantation is considered the only effective treatment for chronic liver disease, it has limitations in that the pool of available donors is vastly insufficient for the number of potential recipients. Even if a patient undergoes liver transplantation, side effects such as immune rejection or bile duct complications could occur. In addition, impaired liver regeneration due to various causes, such as aging and metabolic disorders, may cause liver failure after liver resection, even leading to death. Therefore, further research on the liver regeneration process and therapeutic strategies to improve liver regeneration are needed. In this review, we describe the process of liver regeneration after hepatectomy, focusing on various cytokines and signaling pathways. In addition, we review treatment strategies that have been studied to date to improve liver regeneration, such as promotion of hepatocyte proliferation and metabolism and transplantation of mesenchymal stem cells. This review helps to understand the physiological processes involved in liver regeneration and provides basic knowledge for developing treatments for successful liver regeneration.

Transcriptomic analysis of hepatocytes reveals the association between ubiquitin-specific peptidase 1 and yes-associated protein 1 during liver regeneration

ObjectivesThe liver has an excellent ability to regenerate, and disrupted liver regeneration after various injuries leads to an unfavorable prognosis for patients. In this study, we sought to identify novel therapeutic hallmarks that are associated with yes-associated protein 1 (YAP1)-mediated hepatocyte proliferation during the process of liver regeneration. MethodsPartial hepatectomy was conducted to induce liver regeneration in rats. Primary hepatocytes were isolated and cultured. Hepatocyte proliferation was assessed using immunohistochemistry staining, and expression of YAP1 was detected. RNA sequencing and bioinformatics analysis were used to search for potential regulators of YAP1. The association between ubiquitin-specific peptidase 1 (USP1) and YAP1 was validated using in vivo and in vitro experiments. ResultsYAP1 was significantly elevated in regenerative hepatocytes, especially in the nucleus. Knockdown of YAP1 using small interfering RNA or pharmacological inhibition using verteporfin significantly attenuated the proliferation of hepatocytes. The bioinformatics analysis results revealed that USP1 was associated with YAP1-mediated hepatocyte proliferation during liver regeneration. ML-323, a specific inhibitor of USP1-USP1 associated factor 1 (UAF1), significantly decreased the expression of YAP1, Cyclin D1, and proliferating cell nuclear antigen, while these decreased expressions could be rescued by YAP1 overexpression. Furthermore, ML-323 treatment significantly inhibited liver regeneration following partial hepatectomy. ConclusionsIn conclusion, we identified USP1 as a novel biomarker that is associated with YAP1-mediated hepatocyte proliferation in liver regeneration. Pharmacological inhibition of USP1 by ML-323 substantially impairs hepatocyte proliferation during liver regeneration.

Lack of endothelial autophagy does not impair liver regeneration after partial hepatectomy in mice.

Liver sinusoidal endothelial cells (LSEC) are key elements in regulating the liver response to injury and regeneration. While endothelial autophagy is essential to protect endothelial cells from injury-induced oxidative stress and fibrosis, its role in liver regeneration has not been elucidated. This study was intended to investigate the role of endothelial autophagy in liver regeneration in the context of partial hepatectomy (PHx). Analysis of autophagy levels in rat LSEC after PHx indicated a tendency to decrease activity the first 2 days after surgery. PHx performed in mice with impaired endothelial autophagy (Atg7flox/flox ;VE-Cadherin-Cre+ ) and their littermate controls showed no differences neither in liver-to-body weight ratio, histological analysis, hepatocyte proliferation nor vascular integrity during the first 7 days after PH and liver regeneration was completely achieved. Our results indicate that endothelial autophagy does not play an essential role in the coordination of the liver regeneration process after PHx.

Liver regeneration after partial hepatectomy: the upper optimality estimate

This publication investigates one of the fundamental problems of mathematical biology, specifically the development of mathematical models for the dynamics of complex biosystems that have a satisfactory explanatory and predictable power. A necessary condition for the development of such models is to find a solution for the problem of identifying the objective principles and rules of regulation of the "cellular system", which determines among all the possibilities exactly the "real path" of its dynamics observed in the experiment. One of the promising approaches to solving this problem is based on the hypothesis that the regulation of processes for support/restoration of the dynamic homeostasis of tissues and organs of the body occurs according to certain principles, and criteria of optimality, which have developed due to the natural selection of the body during its previous evolution. It is quite difficult to solve this problem at the current time due to the many uncertainties in the paths of the previous evolution of the organism, the dynamics of changes in external conditions, as well as the high computational complexity of solving such a problem. Instead of this, we have proposed a simplified formulation of the problem of searching for regulation control strategies, which gives us an upper estimate of optimality for the processes of maintaining/restoring dynamic homeostasis of the liver. The upper estimate of the optimality of regulation and testing of hypotheses for the model of liver regeneration was considered in the case of partial hepatectomy and was solved by Python software methods. The result shows that in the case of partial hepatectomy, the liver regeneration strategies obtained in numerous experiments for the problem of the upper optimality estimate qualitatively coincide with the processes of liver regeneration that can be observed during biological experiments. In plenty of experiments following hypotheses were also tested: how significant is the contribution of the process of controlled apoptosis, and how other processes (polyploidy, division, and formation of binuclear hepatocytes) affect the strategy of liver regeneration.

Integrative Multi-Omics Analysis of Identified Ferroptosis-Marker RPL8 as a Candidate Oncogene Correlates with Poor Prognosis and Immune Infiltration in Liver Cancer.

Liver Hepatocellular Carcinoma (LIHC) is characterized by high malignancy, poor prognosis, and high recurrence rate worldwide. The role of ferroptosis in tumorigenesis and progression has been confirmed in previous studies. However, the multi-omics analysis in liver cancer of ferroptosis-markers RPL8 remains to be elucidated. In this analysis, the RPL8 mRNA expression was analyzed via the GEPIA, TIMER and UALCAN databases. In addition, we verified the mRNA expression of RPL8 by qRT-PCR experiment. The Kaplan-Meier plotter, UALCAN, TCGAportal and HPA databases were applied to evaluate RPL8 on prognosis and clinicopathological parameters. Moreover, we used TIMER and Kaplan-Meier plotter to analyze the correlation of RPL8 to immune cell infiltration and immune cell type markers to prognosis. In addition, networks and function enrichment between RPL8 coexpression genes were analyzed by GeneMANIA, cBioportal and Metascape databases. What's more, we used FerrDb and GEPIA databases to analyze the correlation of 23 Ferroptosis-related genes with RPL8. The mRNA expression of RPL8 was over-expressed in multiple cancers. In addition, transcription and translation levels of RPL8 in LIHC were significantly higher than normal tissues. Furthermore, higher expression of RPL8 was closely related to shorter OS in LIHC patients. The analysis of Kaplan-Meier plotter proved that RPL8 expression was related to stage, Sorafenib treatment, alcohol consumption and hepatitis virus. Moreover, the results showed that the methylation expression level of RPL8 was significantly associated with age, gender, grade, stage and TP53 mutation of LIHC. RPL8 and its co-expression genes were primarily involved in liver regeneration and immune system process. Immune infiltration analysis showed the RPL8 expression had positively correlated with immune cells and immune subtypes in LIHC. Furthermore, qRT-PCR experiment validated the expression difference of RPL8 in liver cancer. Our findings elucidated that ferroptosis-markers RPL8 may play an important role in prognosis, and significantly correlate with ferroptosis-related genes, it also revealed the potential of RPL8 as a novel therapeutic target for LIHC treatment and prognosis assessment.

Effect of Hepatic Pathology on Liver Regeneration: The Main Metabolic Mechanisms Causing Impaired Hepatic Regeneration.

Liver regeneration has been studied for many decades, and the mechanisms underlying regeneration of normal liver following resection are well described. However, no less relevant is the study of mechanisms that disrupt the process of liver regeneration. First of all, a violation of liver regeneration can occur in the presence of concomitant hepatic pathology, which is a key factor reducing the liver's regenerative potential. Understanding these mechanisms could enable the rational targeting of specific therapies to either reduce the factors inhibiting regeneration or to directly stimulate liver regeneration. This review describes the known mechanisms of normal liver regeneration and factors that reduce its regenerative potential, primarily at the level of hepatocyte metabolism, in the presence of concomitant hepatic pathology. We also briefly discuss promising strategies for stimulating liver regeneration and those concerning methods for assessing the regenerative potential of the liver, especially intraoperatively.

Monoacylglycerol lipase reprograms hepatocytes and macrophages to promote liver regeneration

Liver regeneration is a repair process in which metabolic reprogramming of parenchymal and inflammatory cells plays a major role. Monoacylglycerol lipase (MAGL) is an ubiquitous enzyme at the crossroad between lipid metabolism and inflammation. It converts monoacylglycerols into free fatty acids and metabolises 2-arachidonoylglycerol into arachidonic acid, being thus the major source of pro-inflammatory prostaglandins in the liver. In this study, we investigated the role of MAGL in liver regeneration. Hepatocyte proliferation was studied invitro in hepatoma cell lines and exvivo in precision-cut human liver slices. Liver regeneration was investigated in mice treated with a pharmacological MAGL inhibitor, MJN110, as well as in animals globally invalidated for MAGL (MAGL-/-) and specifically invalidated in hepatocytes (MAGLHep-/-) or myeloid cells (MAGLMye-/-). Two models of liver regeneration were used: acute toxic carbon tetrachloride injection and two-thirds partial hepatectomy. MAGLMye-/- liver macrophages profiling was analysed by RNA sequencing. A rescue experiment was performed by invivo administration of interferon receptor antibody in MAGLMye-/- mice. Precision-cut human liver slices from patients with chronic liver disease and human hepatocyte cell lines exposed to MJN110 showed reduced hepatocyte proliferation. Mice with global invalidation or mice treated with MJN110 showed blunted liver regeneration. Moreover, mice with specific deletion of MAGL in either hepatocytes or myeloid cells displayed delayed liver regeneration. Mechanistically, MAGLHep-/- mice showed reduced liver eicosanoid production, in particular prostaglandin E2 that negatively impacts on hepatocyte proliferation. MAGL inhibition in macrophages resulted in the induction of the type I interferon pathway. Importantly, neutralising the type I interferon pathway restored liver regeneration of MAGLMye-/- mice. Our data demonstrate that MAGL promotes liver regeneration by hepatocyte and macrophage reprogramming. By using human liver samples and mouse models of global or specific cell type invalidation, we show that the monoacylglycerol pathway plays an essential role in liver regeneration. We unveil the mechanisms by which MAGL expressed in both hepatocytes and macrophages impacts the liver regeneration process, via eicosanoid production by hepatocytes and the modulation of the macrophage interferon pathway profile that restrains hepatocyte proliferation.