The role of hepatocytes and oval cells in liver regeneration and repopulation

General toxicity and screening of reproductive and developmental toxicity following bioaccumulation of oral-dosed perfluorooctanoic acid: Loss of the Golgi apparatus

Despite its widespread use as a stabilizer across various industries over the past several decades, the health effects of chronic exposure to PFOA are still unclear. We administered PFOA by oral gavage (0, 12.5, 50, and 200 μg/day/mouse, eight groups) to male and female mice for six months. Body weight gain decreased with dose accompanied by increased liver weight, and PFOA altered liver damage-related-blood biochemical indicators and induced pathological lesions, including hepatocellular hypertrophy, cholangiofibrosis, and centrilobular hepatocellular vacuolation. Loss of the Golgi apparatus, formation of lamellar body-like structures, and lipid accumulation were observed in the liver of PFOA-treated mice. We also cohabited five pairs of male and female mice for the last ten days of administration, dosed PFOA to dam up to 28 days after birth, and investigated effects on reproduction and development. The survival rate of pups and the sex ratio of surviving mice decreased significantly at the highest dose. PFOA tissue concentration increased with the dose in the parent mice's liver and the pups' blood and brain. Taken together, we suggest that PFOA primarily affects the liver and reproduction system and that disturbance in lipid metabolism and Golgi's structural stability may be involved in PFOA-induced toxicity.

Current Perspectives and Progress in Preoperative Portal Vein Embolization with Stem Cell Augmentation (PVESA)

Portal vein embolization with stem cell augmentation (PVESA) is an emerging approach for enhancing the growth of the liver segment that will remain after surgery (i.e., future liver remnant, FLR) in patients with liver cancer. Conventional portal vein embolization (PVE) aims to induce preoperative FLR growth, but it has a risk of failure in patients with underlying liver dysfunction and comorbid illnesses. PVESA combines PVE with stem cell therapy to potentially improve FLR size and function more effectively and efficiently. Various types of stem cells can help improve liver growth by secreting paracrine signals for hepatocyte growth or by transforming into hepatocytes. Mesenchymal stem cells (MSCs), unrestricted somatic stem cells, and small hepatocyte-like progenitor cells have been used to augment liver growth in preclinical animal models, while clinical studies have demonstrated the benefit of CD133 + bone marrow-derived MSCs and hematopoietic stem cells. These investigations have shown that PVESA is generally safe and enhances liver growth after PVE. However, optimizing the selection, collection, and application of stem cells remains crucial to maximize benefits and minimize risks. Additionally, advanced stem cell technologies, such as priming, genetic modification, and extracellular vesicle-based therapy, that could further enhance efficacy outcomes should be evaluated. Despite its potential, PVESA requires more investigations, particularly mechanistic studies that involve orthotopic animal models of liver cancer with concomitant liver injury as well as larger human trials.

A novel experimental model of MetALD in male mice recapitulates key features of severe alcohol-associated hepatitis

BACKGROUND

The recent increase in the incidence of alcohol-associated hepatitis (AH) coincides with the obesity epidemic in the United States. However, current mouse models do not fully replicate the combined insults of obesity, metabolic dysfunction-associated steatohepatitis, and alcohol. The aim of this study was to develop a new mouse model that recapitulates the robust inflammatory and fibrotic phenotype characteristic of human MetALD.

METHODS

Eight- to 10-week-old male C57BL/6 mice were fed chow or high fat-cholesterol-sugar diet (metabolic dysfunction-associated steatohepatitis diet) and in each group, some received alcohol in drinking water (ad libitum) and weekly alcohol binges (EtOH) for 3 months. The liver was assessed for features of AH.

RESULTS

MetALD mice displayed increased liver damage indicated by highly elevated ALT and bilirubin levels compared to all other groups. Liver steatosis was significantly greater in the MetALD mice compared to all other experimental groups. The inflammatory phenotype of MetALD was also recapitulated, including increased IL-6 and IL-1β protein levels as well as increased CD68+ macrophages and Ly6G+ neutrophils in the liver. Sirius red staining and expression of collagen 1, alpha-smooth muscle actin indicated advanced fibrosis in the livers of MetALD mice. In addition, indicators of epithelial-to-mesenchymal transition markers were increased in MetALD mice compared to all other groups. Furthermore, we found increased ductular reaction, dysregulated hedgehog signaling, and decreased liver synthetic functions, consistent with severe AH.

CONCLUSIONS

Alcohol administration in mice combined with metabolic dysfunction-associated steatohepatitis diet recapitulates key characteristics of human AH including liver damage, steatosis, robust systemic inflammation, and liver immune cell infiltration. This model results in advanced liver fibrosis, ductular reaction, decreased synthetic function, and hepatocyte dedifferentiation, suggesting a robust model of MetALD in mice.

Hepatocytes differentiate into intestinal epithelial cells through a hybrid epithelial/mesenchymal cell state in culture

Hepatocytes play important roles in the liver, but in culture, they immediately lose function and dedifferentiate into progenitor-like cells. Although this unique feature is well-known, the dynamics and mechanisms of hepatocyte dedifferentiation and the differentiation potential of dedifferentiated hepatocytes (dediHeps) require further investigation. Here, we employ a culture system specifically established for hepatic progenitor cells to study hepatocyte dedifferentiation. We found that hepatocytes dedifferentiate with a hybrid epithelial/mesenchymal phenotype, which is required for the induction and maintenance of dediHeps, and exhibit Vimentin-dependent propagation, upon inhibition of the Hippo signaling pathway. The dediHeps re-differentiate into mature hepatocytes by forming aggregates, enabling reconstitution of hepatic tissues in vivo. Moreover, dediHeps have an unexpected differentiation potential into intestinal epithelial cells that can form organoids in three-dimensional culture and reconstitute colonic epithelia after transplantation. This remarkable plasticity will be useful in the study and treatment of intestinal metaplasia and related diseases in the liver.

Epcam regulates intrahepatic bile duct reconstruction in zebrafish, providing a potential model for primary cholangitis model

Epithelial cell adhesion molecules (EpCAMs) have been identified as surface markers of proliferating ductal cells, which are referred to as liver progenitor cells (LPCs), during liver regeneration and correspond to malignancies. These cells can differentiate into hepatocytes and biliary epithelial cells (BECs) in vitro. EpCAM-positive LPCs are involved in liver regeneration following severe liver injury; however, the in vivo function of EpCAMs in the regenerating liver remains unclear. In the present study, we used a zebrafish model of LPC-driven liver regeneration to elucidate the function of EpCAMs in the regenerating liver in vivo. Proliferating ductal cells were observed after severe hepatocyte loss in the zebrafish model. Analyses of the liver size as well as hepatocyte and BEC markers revealed successful conversion of LPCs to hepatocytes and BECs in epcam mutants. Notably, epcam mutants exhibited severe defects in intrahepatic duct maturation and bile acid secretion in regenerating hepatocytes, suggesting that epcam plays a critical role in intrahepatic duct reconstruction during LPC-driven liver regeneration. Our findings provide insights into human diseases involving non-parenchymal cells, such as primary biliary cholangitis, by highlighting the regulatory effect of epcam on intrahepatic duct reconstruction.

Signaling pathways of liver regeneration: Biological mechanisms and implications

The liver possesses a unique regenerative ability to restore its original mass, in this regard, partial hepatectomy (PHx) and partial liver transplantation (PLTx) can be executed smoothly and safely, which has important implications for the treatment of liver disease. Liver regeneration (LR) can be the very complicated procedure that involves multiple cytokines and transcription factors that interact with each other to activate different signaling pathways. Activation of these pathways can drive the LR process, which can be divided into three stages, namely, the initiation, progression, and termination stages. Therefore, it is important to investigate the pathways involved in LR to elucidate the mechanism of LR. This study reviews the latest research on the key signaling pathways in the different stages of LR.

The Ploidy State as a Determinant of Hepatocyte Proliferation

The liver's unique chromosomal variations, including polyploidy and aneuploidy, influence hepatocyte identity and function. Among the most well-studied mammalian polyploid cells, hepatocytes exhibit a dynamic interplay between diploid and polyploid states. The ploidy state is dynamic as hepatocytes move through the "ploidy conveyor," undergoing ploidy reversal and re-polyploidization during proliferation. Both diploid and polyploid hepatocytes actively contribute to proliferation, with diploids demonstrating an enhanced proliferative capacity. This enhanced potential positions diploid hepatocytes as primary drivers of liver proliferation in multiple contexts, including homeostasis, regeneration and repopulation, compensatory proliferation following injury, and oncogenic proliferation. This review discusses the influence of ploidy variations on cellular activity. It presents a model for ploidy-associated hepatocyte proliferation, offering a deeper understanding of liver health and disease with the potential to uncover novel treatment approaches.

Liver protecting effects and molecular mechanisms of icariin and its metabolites

As a detoxification and metabolism organ, the liver plays a vital role in human health. However, an excessive consumption of drugs and toxins, exposure to pathogenic viruses, and unhealthy living habits can lead to liver damage, which may even develop into liver cirrhosis and liver cancer. Epimedium brevicornum Maxim. is a traditional Chinese medicine and dietary supplement in which the flavonoid icariin is a main functional component. Although the protective mechanisms of icariin and its metabolites against liver injury are not yet comprehensively understood, an increasing number of studies have confirmed their liver-protective and anticancer effects. Indeed, icaritin, one of the metabolites of icariin, is currently utilized as an active component of an anti-cancer drug. This paper presents a review of the molecular mechanisms through which icariin and its metabolites actively protect against the occurrence and development of liver injury, and, thus, provides a comprehensive reference for further research and their application in liver protection.

The clinical relevance of OSM in inflammatory diseases: a comprehensive review

Oncostatin M (OSM) is a pleiotropic cytokine involved in a variety of inflammatory responses such as wound healing, liver regeneration, and bone remodeling. As a member of the interleukin-6 (IL-6) family of cytokines, OSM binds the shared receptor gp130, recruits either OSMRβ or LIFRβ, and activates a variety of signaling pathways including the JAK/STAT, MAPK, JNK, and PI3K/AKT pathways. Since its discovery in 1986, OSM has been identified as a significant contributor to a multitude of inflammatory diseases, including arthritis, inflammatory bowel disease, lung and skin disease, cardiovascular disease, and most recently, COVID-19. Additionally, OSM has also been extensively studied in the context of several cancer types including breast, cervical, ovarian, testicular, colon and gastrointestinal, brain,lung, skin, as well as other cancers. While OSM has been recognized as a significant contributor for each of these diseases, and studies have shown OSM inhibition is effective at treating or reducing symptoms, very few therapeutics have succeeded into clinical trials, and none have yet been approved by the FDA for treatment. In this review, we outline the role OSM plays in a variety of inflammatory diseases, including cancer, and outline the previous and current strategies for developing an inhibitor for OSM signaling.

Role of Bile-Derived Extracellular Vesicles in Hepatocellular Proliferation after Partial Hepatectomy in Rats

Although liver regeneration has been extensively studied, the effects of bile-derived extracellular vesicles (bile EVs) on hepatocytes has not been elucidated. We examined the influence of bile EVs, collected from a rat model of 70% partial hepatectomy (PH), on hepatocytes. We produced bile-duct-cannulated rats. Bile was collected over time through an extracorporeal bile duct cannulation tube. Bile EVs were extracted via size exclusion chromatography. The number of EVs released into the bile per liver weight 12 h after PH significantly increased. Bile EVs collected 12 and 24 h post-PH, and after sham surgery (PH12-EVs, PH24-EVs, sham-EVs) were added to the rat hepatocyte cell line, and 24 h later, RNA was extracted and transcriptome analysis performed. The analysis revealed that more upregulated/downregulated genes were observed in the group with PH24-EVs. Moreover, the gene ontology (GO) analysis focusing on the cell cycle revealed an upregulation of 28 types of genes in the PH-24 group, including genes that promote cell cycle progression, compared to the sham group. PH24-EVs induced hepatocyte proliferation in a dose-dependent manner in vitro, whereas sham-Evs showed no significant difference compared to the controls. This study revealed that post-PH bile Evs promote the proliferation of the hepatocytes, and genes promoting cell cycles are upregulated in hepatocytes.

Significance of CCNs in liver regeneration

The liver has an inherent regenerative capacity via hepatocyte proliferation after mild-to-modest damage. When hepatocytes exhaust their replicative ability during chronic or severe liver damage, liver progenitor cells (LPC), also termed oval cells (OC) in rodents, are activated in the form of ductular reaction (DR) as an alternative pathway. LPC is often intimately associated with hepatic stellate cells (HSC) activation to promote liver fibrosis. The Cyr61/CTGF/Nov (CCN) protein family consists of six extracellular signaling modulators (CCN1-CCN6) with affinity to a repertoire of receptors, growth factors, and extracellular matrix proteins. Through these interactions, CCN proteins organize microenvironments and modulate cell signalings in a diverse variety of physiopathological processes. In particular, their binding to subtypes of integrin (αvβ5, αvβ3, α6β1, αvβ6, etc.) influences the motility and mobility of macrophages, hepatocytes, HSC, and LPC/OC during liver injury. This paper summarizes the current understanding of the significance of CCN genes in liver regeneration in relation to hepatocyte-driven or LPC/OC-mediated pathways. Publicly available datasets were also searched to compare dynamic levels of CCNs in developing and regenerating livers. These insights not only add to our understanding of the regenerative capability of the liver but also provide potential targets for the pharmacological management of liver repair in the clinical setting. Ccns in liver regeneration Restoring damaged or lost tissues requires robust cell growth and dynamic matrix remodeling. Ccns are matricellular proteins highly capable of influencing cell state and matrix production. Current studies have identified Ccns as active players in liver regeneration. Cell types, modes of action, and mechanisms of Ccn induction may vary depending on liver injuries. Hepatocyte proliferation is a default pathway for liver regeneration following mild-to-modest damages, working in parallel with the transient activation of stromal cells, such as macrophages and hepatic stellate cells (HSC). Liver progenitor cells (LPC), also termed oval cells (OC) in rodents, are activated in the form of ductular reaction (DR) and are associated with sustained fibrosis when hepatocytes lose their proliferative ability in severe or chronic liver damage. Ccns may facilitate both hepatocyte regeneration and LPC/OC repair via various mediators (growth factors, matrix proteins, integrins, etc.) for cell-specific and context-dependent functions.

Effect of Antiviral Treatment on Hepatitis B Virus Integration and Hepatocyte Clonal Expansion

BACKGROUND

This study investigated the effect of nucleos(t)ide analogue (NUC) treatment on hepatitis B virus (HBV) DNA integration and hepatocyte clonal expansion, both of which are implicated in hepatocellular carcinoma (HCC) in chronic hepatitis B.

METHODS

Twenty-eight patients receiving NUCs (11 lamivudine, 7 telbivudine, 10 entecavir) were included. All had liver biopsies at baseline and year 1, and 7 had a third biopsy at year 10. HBV DNA integration and hepatocyte clone size were assessed by inverse polymerase chain reaction.

RESULTS

All patients had detectable HBV integration at baseline, with a median integration frequency of 1.01 × 109 per liver and hepatocyte clone size of 2.41 × 105. Neither integration frequency nor hepatocyte clone size correlated with age and HBV virologic parameters. After 1 year of treatment, HBV integration was still detectable in all patients, with a median of 5.74 × 108 integration per liver (0.22 log reduction; P = .008) and hepatocyte clone size of 1.22 × 105 (0.40 log reduction; P = .002). HBV integration remained detectable at year 10 of treatment, with a median integration frequency of 4.84 × 107 integration per liver (0.93 log reduction from baseline) and hepatocyte clone size of 2.55 × 104 (1.02 log reduction from baseline). From baseline through year 1 to year 10, there was a decreasing trend in both integration frequency and hepatocyte clone size (P = .066 and.018, respectively).

CONCLUSIONS

NUCs reduced both HBV DNA integration and hepatocyte clonal expansion, suggesting another alternative pathway besides direct viral suppression to reduce HCC risk. Our findings supported the notion for a long-term NUC treatment to prevent HCC.

Elucidating the Mechanisms of Dynamic and Robust Control of the Liver Homeostatic Renewal Process: Cell Network Modeling and Analysis

Recent experimental investigations of liver homeostatic renewal have identified high replication capacity hepatocyte populations as the primary maintainers of liver mass. However, the molecular and cellular processes controlling liver homeostatic renewal remain unknown. To address this problem, we developed and analyzed a mathematical model describing cellular network interactions underlying liver homeostatic renewal. Model simulation results demonstrate that without feedback control, basic homeostatic renewal is not robust to disruptions, leading to tissue loss under persistent/repetitive insults. Consequently, we extended our basic model to incorporate putative regulatory interactions and investigated how such interactions may confer robustness on the homeostatic renewal process. We utilized a Design of Experiments approach to identify the combination of feedback interactions that yields a cell network model of homeostatic renewal capable of maintaining liver mass robustly during persistent/repetitive injury. Simulations of this robust model indicate that repeated injury destabilizes liver homeostasis within several months, which differs from epidemiological observations of a much slower decay of liver function occurring over several years. To address this discrepancy, we extended the model to include feedback control by liver nonparenchymal cells. Simulations and analysis of the final multicellular feedback control network suggest that achieving robust liver homeostatic renewal requires intrinsic stability in a hepatocellular network combined with feedback control by nonparenchymal cells.

YAP regulates the liver size during the fasting-refeeding transition in mice

Liver is the central hub regulating energy metabolism during feeding-fasting transition. Evidence suggests that fasting and refeeding induce dynamic changes in liver size, but the underlying mechanisms remain unclear. Yes-associated protein (YAP) is a key regulator of organ size. This study aims to explore the role of YAP in fasting- and refeeding-induced changes in liver size. Here, fasting significantly reduced liver size, which was recovered to the normal level after refeeding. Moreover, hepatocyte size was decreased and hepatocyte proliferation was inhibited after fasting. Conversely, refeeding promoted hepatocyte enlargement and proliferation compared to fasted state. Mechanistically, fasting or refeeding regulated the expression of YAP and its downstream targets, as well as the proliferation-related protein cyclin D1 (CCND1). Furthermore, fasting significantly reduced the liver size in AAV-control mice, which was mitigated in AAV Yap (5SA) mice. Yap overexpression also prevented the effect of fasting on hepatocyte size and proliferation. Besides, the recovery of liver size after refeeding was delayed in AAV Yap shRNA mice. Yap knockdown attenuated refeeding-induced hepatocyte enlargement and proliferation. In summary, this study demonstrated that YAP plays an important role in dynamic changes of liver size during fasting-refeeding transition, which provides new evidence for YAP in regulating liver size under energy stress.

Polysaccharide-based hydrogels for drug delivery and wound management: a review

INTRODUCTION

Polysaccharide-based hydrogels (PBHs) offer several advantages over their synthetic counterparts. Their natural origin contributes to their nontoxicity, high biocompatibility, and in vivo biodegradability. Their properties can be tuned finely to obtain hydrogels with desired mechanical, structural, and chemical properties.

AREAS COVERED

Such versatile characteristics have potentiated the use of PBHs for the delivery of drugs, vaccines, protein and peptide therapeutics, genes, cells, probiotics, bacteriophages, and other therapeutic agents. Recent advances in hydrogel-based formulations such as nanogels, microgels, microneedles, hydrogel beads, nanocarrier-loaded hydrogels, and complexation hydrogels have enabled the precise delivery of a wide range of therapeutics. This review aims to give a holistic overview of hydrogels in the delivery of a variety of therapeutics through different routes.

EXPERT OPINION

PBHs have been used to enable the oral delivery of vaccines and other biologicals, thereby allowing self-administration of life-saving vaccines during public health emergencies. There is a lack of commercialized wound dressings for the treatment of chronic wounds. PBH-based wound dressings, especially those based on chitosan and loaded with actives and growth factors, have the potential to help in the long-term treatment of such wounds. Recent developments in the 3D printing of hydrogels can enable the quick and large-scale production of drug-loaded hydrogels.

Wnt/β-catenin targeting in liver carcinoma through nanotechnology-based drug repurposing: A review

Liver cancer is the fifth most widespread in the world, with a high fatality rate and poor prognosis.However,surgicalresction,thermal/radiofrequencyablation,chemo/radioembolization and pathway targeting to the cancer cells are all possible options for treating Liver Carcinoma. Unfortunately, once the tumour has developed and spread, diagnosis often occurs too late. The targeted therapy has demonstrated notable, albeit modest, efficacy in some patients with advanced HCC. This demonstrates the necessity of creating additional focused treatments and, in pursuit of this end, the need to find ever-more pathways as prospective targets. Despite the critical need, there are currently no Wnt signalling directed therapy on the research field, only a few methods have progressed beyond the early stage of clinical studies. In the present study, we report that repurposing of drug previously licensed for other diseases is one possible strategy inhibit malignant cell proliferation and renewal by removing individuals protein expression in the Wnt/β-catenin pathway. Particularly β-catenin complex is present in Liver cancer, where tumour necrosis factor is indispensable for the complex formation and β-catenin interactions are disrupted upon drug in nano-carrier through nanotechnology. This study findings not only highlight that repurposing drug could improve liver cancer treatment outcomes but also focused to character traits and functions of the Wnt signalling cascade's molecular targets and how they could be used to get anti-tumour results method to targeting Wnt/β-catenin in liver carcinoma.

Liver regeneration after partial hepatectomy is improved in the absence of aryl hydrocarbon receptor

The liver is among the few organs having the ability to self-regenerate in response to a severe damage compromising its functionality. The Aryl hydrocarbon receptor (Ahr) is a transcription factor relevant for the detoxification of xenobiotics but also largely important for liver development and homeostasis. Hence, liver cell differentiation is developmentally modulated by Ahr through the controlled expression of pluripotency and stemness-inducing genes. Here, 2/3 partial hepatectomy (PH) was used as a clinically relevant approach to induce liver regeneration in Ahr-expressing (Ahr^+/+) and Ahr-null (Ahr^−/−) mice. Ahr expression and activity were early induced after 2/3 PH to be gradually downmodulated latter during regeneration. Ahr^−/− mice triggered liver regeneration much faster than AhR^+/+ animals, although both reached full regeneration at the latest times. At initial stages after PHx, earlier regenerating Ahr^−/− livers had upregulation of cell proliferation markers and increased activation of signalling pathways related to stemness such as Hippo-YAP and Wnt/β-catenin, concomitantly with the induction of pro-inflammatory cytokines TNFa, IL6 and p65. These phenotypes, together with the improved metabolic adaptation of Ahr^−/− mice after PHx and their induced sustained cell proliferation, could likely result from the expansion of undifferentiated stem cells residing in the liver expressing OCT4, SOX2, KLF4 and NANOG. We propose that Ahr needs to be induced early during regeneration to fine-tune liver regrowth to physiological values. Since Ahr deficiency did not result in liver overgrowth, its transient pharmacological inhibition could serve to improve liver regeneration in hepatectomized and transplanted patients and in those exposed to damaging liver toxins and carcinogens.

Therapeutic efficacy of rscAAVrh74.miniCMV.LIPA gene therapy in a mouse model of lysosomal acid lipase deficiency

Lysosomal acid lipase deficiency (LAL-D) presents as one of two rare autosomal recessive diseases: Wolman disease (WD), a severe disorder presenting in infancy characterized by absent or very low LAL activity, and cholesteryl ester storage disease (CESD), a less severe, later onset disease form. Recent clinical studies have shown efficacy of enzyme replacement therapy for both forms of LAL-D; however, no gene therapy approach has yet been developed for clinical use. Here, we show that rscAAVrh74.miniCMV.LIPA gene therapy can significantly improve disease symptoms in the Lipa^−/− mouse model of LAL-D. Treatment dramatically lowered hepatosplenomegaly, liver and spleen triglyceride and cholesterol levels, and serum expression of markers of liver damage. Measures of liver inflammation and fibrosis were also reduced. Treatment of young adult mice was more effective than treatment of neonates, and enzyme activity was elevated in serum, consistent with possible bystander effects. These results demonstrate that adeno associated virus (AAV)-mediated LIPA gene-replacement therapy may be a viable option to treat patients with LAL-D, particularly patients with CESD.

3-deazaadenosine (3DA) alleviates senescence to promote cellular fitness and cell therapy efficiency in mice

Cellular senescence is a stable type of cell cycle arrest triggered by different stresses. As such, senescence drives age-related diseases and curbs cellular replicative potential. Here, we show that 3-deazaadenosine (3DA), an S-adenosyl homocysteinase (AHCY) inhibitor, alleviates replicative and oncogene-induced senescence. 3DA-treated senescent cells showed reduced global Histone H3 Lysine 36 trimethylation (H3K36me3), an epigenetic modification that marks the bodies of actively transcribed genes. By integrating transcriptome and epigenome data, we demonstrate that 3DA treatment affects key factors of the senescence transcriptional program. Remarkably, 3DA treatment alleviated senescence and increased the proliferative and regenerative potential of muscle stem cells from very old mice in vitro and in vivo. Moreover, ex vivo 3DA treatment was sufficient to enhance the engraftment of human umbilical cord blood (UCB) cells in immunocompromised mice. Together, our results identify 3DA as a promising drug enhancing the efficiency of cellular therapies by restraining senescence.

Intracellular alpha-fetoprotein mitigates hepatocyte apoptosis and necroptosis by inhibiting endoplasmic reticulum stress

BACKGROUND

Endoplasmic reticulum (ER) stress contributes to the pathogenesis of chronic liver diseases, but how hepatocytes respond to ER stress has not been clarified. Alpha-fetoprotein (AFP) is secreted by hepatoma cells and elevated levels of serum AFP are associated with development of liver malignancies.

AIM

To investigate whether and how AFP could regulate ER stress and hepatocyte injury.

METHODS

The distribution of AFP and the degrees of ER stress in liver tissues and liver injury were characterized by histology, immunohistochemistry, and Western blot in biopsied human liver specimens, two mouse models of liver injury and a cellular model. The levels of AFP in sera and the supernatants of cultured cells were quantified by chemiluminescence.

RESULTS

High levels of intracellular AFP were detected in liver tissues, particularly in the necrotic areas, from patients with chronic liver diseases and mice after carbon tetrachloride (CCl₄) administration or induction of ER stress, but not from the controls. The induced intracellular AFP was accompanied by elevated activating transcription factor-6 (ATF6) expression and protein kinase R-like ER kinase (PERK) phosphorylation in mouse livers. ER stress induced AFP expression in LO2 cells and decreased their viability. ATF6, but not PERK, silencing mitigated the ER-stress-induced AFP expression in LO2 cells. Conversely, AFP silencing deteriorated the ER stress-mediated LO2 cell injury and CCl₄ administration-induced liver damages by increasing levels of cleaved caspase-3, the C/enhancer binding protein homologous protein expression, mixed lineage kinase domain-like pseudokinase and PERK phosphorylation, but decreasing ATF6 expression.

CONCLUSION

ER stress upregulated intra-hepatocyte AFP expression by activating ATF6 during the process of liver injury and intracellular AFP attenuated hepatocyte apoptosis and necroptosis by alleviating ER stress.

Small-molecule inhibitor cocktail promotes the proliferation of pre-existing liver progenitor cells

A recent study showed that a cocktail of three small molecules, Y-27632, A83-01, and CHIR99021 (YAC), converts mature hepatocytes (MHs) into proliferative bipotent cells that can be induced into MHs and cholangiocytes in rats. However, when we reproduced these experiments, it was found that bipotent cells may be derived from resident liver progenitor cells (LPCs), whose proliferative activity was promoted by YAC. A simple and efficient sorting scheme was also developed in this study to harvest high-purity and high-yield LPCs. The inducible bipotency of purified LPCs was verified; in addition, they were found to spontaneously differentiate into hepatocytes and cholangiocytes due to changes in proliferative status even without induction. Moreover, during the differentiation process, some hepatocytes spontaneously reconverted to LPCs under certain conditions, such as the release of contact inhibition. These findings may improve our understanding of LPCs and provide a cell source for regenerative medicine.

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A small-molecule cocktail promotes rat liver progenitor proliferation in vitro

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Highly purified progenitors can be simply obtained by their physical properties

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Purified progenitors preferentially proliferate and then spontaneously differentiate

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Progenitor differentiation is closely related to varied proliferation signals

Liver regeneration: Cellular origin and molecular mechanisms

The liver is known as an organ with high proliferation potential. Clarifying the cellular origin and deepening the understanding of liver regeneration mechanisms will help provide new directions for the treatment of liver disease. With the development and application of lineage tracing technology, the specific distribution and dynamic changes of hepatocyte subpopulations in homeostasis and liver injury have been illustrated. Self-replication of hepatocytes is responsible for the maintenance of liver function and mass under homeostasis. The compensatory proliferation of remaining hepatocytes is the main mechanism of liver regeneration following acute and chronic liver injury. Transdifferentiation between hepatocytes and cholangiocytes has been recognized upon severe chronic liver injury. Wnt/β-catenin, Hippo/YAP and Notch signalling play essential roles in the maintenance of homeostatic liver and hepatocyte-to-cholangiocyte conversion under liver injury. In this review, we summarized the recent studies on cell origin of newly generated hepatocytes and the underlying mechanisms of liver regeneration in homeostasis and liver injury.

Murine Falcor/LL35 lncRNA Contributes to Glucose and Lipid Metabolism In Vitro and In Vivo

Glucose and lipid metabolism are crucial functional systems in eukaryotes. A large number of experimental studies both in animal models and humans have shown that long non-coding RNAs (lncRNAs) play an important role in glucose and lipid metabolism. Previously, human lncRNA DEANR1/linc00261 was described as a tumor suppressor that regulates a variety of biological processes such as cell proliferation, apoptosis, glucose metabolism and tumorigenesis. Here we report that murine lncRNA Falcor/LL35, a proposed functional analog of human DEANR1/linc00261, is predominantly expressed in murine normal hepatocytes and downregulated in HCC and after partial hepatectomy. The application of high-throughput approaches such as RNA-seq, LC-MS proteomics, lipidomics and metabolomics analysis allowed changes to be found in the transcriptome, proteome, lipidome and metabolome of hepatocytes after LL35 depletion. We revealed that LL35 is involved in the regulation of glycolysis and lipid biosynthesis in vitro and in vivo. Moreover, LL35 affects Notch and NF-κB signaling pathways in normal hepatocytes. All observed changes result in the decrease in the proliferation and migration of hepatocytes. We demonstrated similar phenotype changes between murine LL35 and human linc00261 depletion in vitro and in vivo that opens the opportunity to translate results for LL35 from a liver murine model to possible functions of human lncRNA linc00261.

In vitro proliferation and long-term preservation of functional primary rat hepatocytes in cell fibers

Primary hepatocytes are essential cellular resources for drug screening and medical transplantation. While culture systems have already succeeded in reconstituting the biomimetic microenvironment of primary hepatocytes, acquiring additional capabilities to handle them easily as well as to expand them remains unmet needs. This paper describes a culture system for primary rat hepatocytes, based on cell fiber technology, that brings scalability and handleability. Cell fibers are cell-laden core–shell hydrogel microfibers; in the core regions, cells are embedded in extracellular matrix proteins, cultured three-dimensionally, and exposed to soluble growth factors in the culture medium via the hydrogel shells. By encapsulating primary rat hepatocytes within cell fibers, we first demonstrated their proliferation while maintaining their viability and their hepatic specific functions for up to thirty days of subsequent culture. We then demonstrated the efficiency of proliferating primary rat hepatocytes in cell fibers not only as cell-based sensors to detect drugs that damage hepatic functions and hepatocellular processes but also as transplants to improve the plasma albumin concentrations of congenital analbuminemia. Our culture system could therefore be included in innovative strategies and promising developments in applying primary hepatocytes to both pharmaceutical and medical fields.

Integration of Adverse Outcome Pathways, Causal Networks and ‘Omics to Support Chemical Hazard Assessment

Several approaches have been used in an attempt to simplify and codify the events that lead to adverse effects of chemicals including systems biology, ‘omics, in vitro assays and frameworks such as the Adverse Outcome Pathway (AOP). However, these approaches are generally not integrated despite their complementary nature. Here we propose to integrate toxicogenomics data, systems biology information and AOPs using causal biological networks to define Key Events in AOPs. We demonstrate this by developing a causal subnetwork of 28 nodes that represents the Key Event of regenerative proliferation – a critical event in AOPs for liver cancer. We then assessed the effects of three chemicals known to cause liver injury and cell proliferation (carbon tetrachloride, aflatoxin B₁, thioacetamide) and two with no known cell proliferation effects (diazepam, simvastatin) on the subnetwork using rat liver gene expression data from the toxicogenomic database Open TG-GATEs. Cyclin D1 (Ccnd1), a gene both causally linked to and sufficient to infer regenerative proliferation activity, was overexpressed after exposures to carbon tetrachloride, aflatoxin B₁ and thioacetamide, but not in exposures to diazepam and simvastatin. These results were consistent with known effects on rat livers and liver pathology of exposed rats. Using these approaches, we demonstrate that transcriptomics, AOPs and systems biology can be applied to examine the presence and progression of AOPs in order to better understand the hazards of chemical exposure.

CK19 and OV6 Expressions in the Liver of 2-AAF/CCl4 Rat Model

BACKGROUND: Liver regeneration on a chronic liver injury with rat model research is urgent to study the pathology of human chronic diseases. 2-Acetylaminofluorene (2-AAF) and Carbon Tetrachloride (CCl4) can be applied to study about liver regeneration by liver stem cells, known as oval cells. The use of 2-AAF and CCl4 (2-AAF/CCl4) to induce chronic liver injury can lead severe hepatocyte damages and extensive fibrosis. AIM: to observed the OV6 and CK19 expression in the liver of 2AAF/CCl4 rat model. METHODS: In this research, a high dose of 2-AAF (10mg/kg) was applied and combined repeatedly with CCl4 (2ml/kg) for 12 weeks. An immunohistochemistry (IHC) procedure by using OV6 and CK19 antibodies was also applied to examine the regeneration of oval cells. Both antibodies expressions were then examined semi-quantitatively according to the expressions percentage of each sample based on the liver zone. We have observed the OV6 and CK19 expressions in every zone, including in portae hepatis area.   RESULTS: The results showed that OV6 and CK19 with the highest expression in the zone I. A significant difference between OV6 and CK19 expressions was revealed in healthy (control group) and 2-AAF/CCl4 groups (both indicating p=0.045). Moreover, a ductular reaction was also found in Zone I and II of the 2-AAF/CCl4. CONCLUSIONS: We conclude that 2-AAF/CCl4 induced chronic rat liver injury model, could be utilized to investigate the oval cells with OV6 and CK19 expression.

Folinic Acid Potentiates the Liver Regeneration Process after Selective Portal Vein Ligation in Rats

Simple Summary

Fewer than 30% of patients with liver metastases are eligible for major liver resection, because liver remaining after such a surgery would be insufficient to cover the patient’s needs; this is called a low percentage of future liver remnant (FLR). Folinic acid (FA) has been shown to play a crucial role in cellular synthesis, regeneration, and nucleotide and amino acid biosynthesis. The aim of this piece of research was to evaluate the effect of FA as a potential hypertrophic hepatic enhancer agent after selective portal vein ligation (PVL) to ensure adequate FLR. We have confirmed in our rodent model that FA accelerates liver regeneration after PVL and enhances recovery of liver function. These findings may allow more patients to be eligible for liver resection without jeopardizing postoperative liver function.

Abstract

Liver resection remains the gold standard for hepatic metastases. The future liver remnant (FLR) and its functional status are two key points to consider before performing major liver resections, since patients with less than 25% FLR or a Child–Pugh B or C grade are not eligible for this procedure. Folinic acid (FA) is an essential agent in cell replication processes. Herein, we analyze the effect of FA as an enhancer of liver regeneration after selective portal vein ligation (PVL). Sixty-four male WAG/RijHsd rats were randomly distributed into eight groups: a control group and seven subjected to 50% PVL, by ligation of left portal branch. The treated animals received FA (2.5 m/kg), while the rest were given saline. After 36 h, 3 days or 7 days, liver tissue and blood samples were obtained. FA slightly but significantly increased FLR percentage (FLR%) on the 7th day (91.88 ± 0.61%) compared to control or saline-treated groups (86.72 ± 2.5 vs. 87 ± 3.33%; p < 0.01). The hepatocyte nuclear area was also increased both at 36 h and 7days with FA (61.55 ± 16.09 µm², and 49.91 ± 15.38 µm²; p < 0.001). Finally, FA also improved liver function. In conclusion, FA has boosted liver regeneration assessed by FLR%, nuclear area size and restoration of liver function after PVL.

Isolation of Small Hepatocyte-Like Progenitor Cells from Retrorsine/Partial Hepatectomy Rat Livers by Laser Microdissection

Small hepatocyte-like progenitor cells (SHPCs) are known as liver stem/progenitor cells (LSPCs). SHPCs transiently appear and form clusters in rat livers treated with retrorsine (Ret) and a 70% partial hepatectomy (PH). The Ret/PH model has been used widely to analyze the effectiveness of cell transplantation and the mechanisms of LSPC proliferation. Laser microdissection (LMD) is a powerful tool that can excise and collect specific areas of cells from a tissue slice with a laser under a microscope. These cells exhibiting morphological alterations different from the surrounding cells may be analyzed by gene expression profiling. Specific markers of SHPCs have not yet been identified, in part, because it is difficult to isolate SHPCs from the liver using fluorescence or magnetic-activated cell sorting. To examine the underlying mechanism for SHPC growth, we established comprehensive gene expression profiles for SHPCs captured from liver sections using LMD. In this chapter, we introduce a method to isolate SHPCs from liver tissue sections using LMD for gene expression analysis.

Global sensitivity analysis of a single-cell HBV model for viral dynamics in the liver

The predictive accuracy of mathematical models representing anything ranging from the meteorological to the biological system profoundly depends on the quality of model parameters derived from experimental data. Hence, robust sensitivity analysis (SA) of these critical model parameters aids in sifting the influential from the negligible out of typically vast parameter regimes, thus illuminating key components of the system under study. We here move beyond traditional local sensitivity analysis to the adoption of global SA techniques. Partial rank correlation coefficient (PRCC) based on Latin hypercube sampling is compared with the variance-based Sobol method. We selected for this SA investigation an infection model for the hepatitis-B virus (HBV) that describes infection dynamics and clearance of HBV in the liver [Murray & Goyal, 2015]. The model tracks viral particles such as the tenacious and nearly ineradicable covalently closed circular DNA (cccDNA) embedded in infected nuclei and an HBV protein known as p36. Our application of these SA methods to the HBV model illuminates, especially over time, the quantitative relationships between cccDNA synthesis rate and p36 synthesis and export. Our results reinforce previous observations that the viral protein, p36, is by far the most influential factor for cccDNA replication. Moreover, both methods are capable of finding crucial parameters of the model. Though the Sobol method is independent of model structure (e.g., linearity and monotonicity) and well suited for SA, our results ensure that LHS-PRCC suffices for SA of a non-linear model if it is monotonic.

New insights into IL-6 family cytokines in metabolism, hepatology and gastroenterology

IL-6 family cytokines are defined by the common use of the signal-transducing receptor chain glycoprotein 130 (gp130). Increasing evidence indicates that these cytokines are essential in the regulation of metabolic homeostasis as well as in the pathophysiology of multiple gastrointestinal and liver disorders, thus making them attractive therapeutic targets. Over the past few years, therapies modulating gp130 signalling have grown exponentially in several clinical settings including obesity, cancer and inflammatory bowel disease. A newly engineered gp130 cytokine, IC7Fc, has shown promising preclinical results for the treatment of type 2 diabetes, obesity and liver steatosis. Moreover, drugs that modulate gp130 signalling have shown promise in refractory inflammatory bowel disease in clinical trials. A deeper understanding of the main roles of the IL-6 family of cytokines during homeostatic and pathological conditions, their signalling pathways, sources of production and target cells will be crucial to the development of improved treatments. Here, we review the current state of the role of these cytokines in hepatology and gastroenterology and discuss the progress achieved in translating therapeutics targeting gp130 signalling into clinical practice.

Generation of Hepatobiliary Cell Lineages from Human Induced Pluripotent Stem Cells: Applications in Disease Modeling and Drug Screening

The possibility to reproduce key tissue functions in vitro from induced pluripotent stem cells (iPSCs) is offering an incredible opportunity to gain better insight into biological mechanisms underlying development and disease, and a tool for the rapid screening of drug candidates. This review attempts to summarize recent strategies for specification of iPSCs towards hepatobiliary lineages -hepatocytes and cholangiocytes-and their use as platforms for disease modeling and drug testing. The application of different tissue-engineering methods to promote accurate and reliable readouts is discussed. Space is given to open questions, including to what extent these novel systems can be informative. Potential pathways for improvement are finally suggested.

Reptin/RUVBL2 is required for hepatocyte proliferation in vivo, liver regeneration and homeostasis

Previous studies have shown that Reptin is overexpressed in hepatocellular carcinoma and that it is necessary for in vitro proliferation and cell survival. However, its pathophysiological role in vivo remains unknown. We aimed to study the role of Reptin in hepatocyte proliferation after regeneration using a liver Reptin knock-out model (Reptin^LKO ). Interestingly, hepatocyte proliferation is strongly impaired in Reptin^LKO mice 36 h after partial hepatectomy, associated with a decrease of cyclin-A expression and mTORC1 and MAPK signalling, leading to an impaired liver regeneration. Moreover, in the Reptin^LKO model, we have observed a progressive loss of Reptin invalidation associated with an atypical liver regeneration. Hypertrophic and proliferative hepatocytes gradually replace Reptin^KO hypotrophic hepatocytes. To conclude, our results show that Reptin is required for hepatocyte proliferation in vivo and liver regeneration and that it plays a crucial role in hepatocyte survival and liver homeostasis.

Role of Biliary Organoids in Cholestasis Research and Regenerative Medicine

Translational studies in human cholestatic diseases have for years been hindered by various challenges, including the rarity of the disorders, the difficulty in obtaining biliary tissue from across the spectrum of the disease stage, and the difficulty culturing and maintaining primary cholangiocytes. Organoid technology is increasingly being viewed as a technological breakthrough in translational medicine as it allows the culture and biobanking of self-organizing cells from various sources that facilitate the study of pathophysiology and therapeutics, including from individual patients in a personalized approach. This review describes current research using biliary organoids for the study of human cholestatic diseases and the emerging applications of organoids to regenerative medicine directed at the biliary tree. Challenges and possible solutions to the current hurdles in this emerging field, particularly the need for standardization of terminology and clarity on source materials and techniques, are also discussed.

Aquaporins implicated in the cell proliferation and the signaling pathways of cell stemness

Aquaporins (AQPs) are water channel proteins facilitating passive transport of water and other small molecules across biomembranes. Regulation of osmotic homeostasis via AQPs is accompanied by dynamic participation of various cellular signaling pathways. Recently emerging evidence reveals that functional roles of AQPs are further extended from the osmotic regulation via water permeation into the cell proliferation and differentiation. In particular, anomalous expression of AQPs has been demonstrated in various types of cancer cells and cancer stem-like cells and it has been proposed as markers for proliferation and progression of cancer cells. Thus, a more comprehensive view on AQPs could bring a great interest in the cell stemness accompanied by the expression of AQPs. AQPs are broadly expressed across tissues and cells in a cell type- and lineage-specific manner during development via spatiotemporal transcriptional regulation. Moreover, AQPs are expressed in various adult stem cells and cells associated with a stem cell niche as well as cancer stem-like cells. However, the expression and regulatory mechanisms of AQP expression in stem cells have not been well understood. This review highlighted the AQPs expression in stem cell niches/stem cells and the involvement of AQPs in the cell proliferation and signaling pathways associated with cell stemness.

RNA Interference Therapy for Chronic Hepatitis B Predicts the Importance of Addressing Viral Integration When Developing Novel Cure Strategies

Chronic hepatitis B infection remains a globally important cause of morbidity and mortality and has recently undergone a renaissance in therapeutic interest with increased pre-clinical and clinical testing of new drug classes. One of the first new classes in the clinic was RNA interference agents, which have the potential to impact the entire viral life cycle by reducing all virus-produced mRNA. Early clinical testing with the first of these agents in the clinic, ARC-520, demonstrated that rapid and deep reductions in viral proteins, RNA and DNA could be produced with this approach, but also the surprising insight that HBsAg production from incomplete HBV DNA integrated into the host genome appears to play a heretofore unappreciated and important role in maintaining circulating HBsAg, thought to play a fundamental role in preventing host clearance of the virus. Thus, accounting for viral DNA integration in novel HBV treatment approaches may prove to be essential to achieving successful finite therapies of this difficult to treat chronic infection.

Contributions of biliary epithelial cells to hepatocyte homeostasis and regeneration in zebrafish

Whether transdifferentiation of the biliary epithelial cells (BECs) to hepatocytes occurs under physiological conditions and contributes to liver homeostasis remains under long-term debate. Similar questions have been raised under pathological circumstances if a fibrotic liver is suffered from severe injuries. To address these questions in zebrafish, we established a sensitive lineage tracing system specific for the detection of BEC-derived hepatocytes. The BEC-to-hepatocyte transdifferentiation occurred and became minor contributors to hepatocyte homeostasis in a portion of adult individuals. The BEC-derived hepatocytes distributed in clusters in the liver. When a fibrotic liver underwent extreme hepatocyte damages, BEC-to-hepatocyte transdifferentiation acted as the major origin of regenerating hepatocytes. In contrast, partial hepatectomy failed to induce the BEC-to-hepatocyte conversion. In conclusion, based on a sensitive lineage tracing system, our results suggest that BECs are able to transdifferentiate into hepatocytes and contribute to both physiological hepatocyte homeostasis and pathological regeneration.

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Developed sensitivity system to trace BECs derived hepatocytes in liver homeostasis

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BECs convert to hepatocytes in liver homeostasis but are individually heterogeneous

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BECs are the primary regeneration sources in the extreme injury of the fibrotic liver

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BECs fail to contribute to new hepatocytes after partial hepatectomy

Genome editing in the human liver: Progress and translational considerations

Liver-targeted genome editing offers the prospect of life-long therapeutic benefit following a single treatment and is set to rapidly supplant conventional gene addition approaches. Combining progress in liver-targeted gene delivery with genome editing technology, makes this not only feasible but realistically achievable in the near term. However, important challenges remain to be addressed. These include achieving therapeutic levels of editing, particularly in vivo, avoidance of off-target effects on the genome and the potential impact of pre-existing immunity to bacteria-derived nucleases, when used to improve editing rates. In this chapter, we outline the unique features of the liver that make it an attractive target for genome editing, the impact of liver biology on therapeutic efficacy, and disease specific challenges, including whether the approach targets a cell autonomous or non-cell autonomous disease. We also discuss strategies that have been used successfully to achieve genome editing outcomes in the liver and address translational considerations as genome editing technology moves into the clinic.

TMEM9-v-ATPase Activates Wnt/β-Catenin Signaling Via APC Lysosomal Degradation for Liver Regeneration and Tumorigenesis

BACKGROUND AND AIMS

How Wnt signaling is orchestrated in liver regeneration and tumorigenesis remains elusive. Recently, we identified transmembrane protein 9 (TMEM9) as a Wnt signaling amplifier.

APPROACH AND RESULTS

TMEM9 facilitates v-ATPase assembly for vesicular acidification and lysosomal protein degradation. TMEM9 is highly expressed in regenerating liver and hepatocellular carcinoma (HCC) cells. TMEM9 expression is enriched in the hepatocytes around the central vein and acutely induced by injury. In mice, Tmem9 knockout impairs hepatic regeneration with aberrantly increased adenomatosis polyposis coli (Apc) and reduced Wnt signaling. Mechanistically, TMEM9 down-regulates APC through lysosomal protein degradation through v-ATPase. In HCC, TMEM9 is overexpressed and necessary to maintain β-catenin hyperactivation. TMEM9-up-regulated APC binds to and inhibits nuclear translocation of β-catenin, independent of HCC-associated β-catenin mutations. Pharmacological blockade of TMEM9-v-ATPase or lysosomal degradation suppresses Wnt/β-catenin through APC stabilization and β-catenin cytosolic retention.

CONCLUSIONS

Our results reveal that TMEM9 hyperactivates Wnt signaling for liver regeneration and tumorigenesis through lysosomal degradation of APC.

Advances in Liver Cancer Stem Cell Isolation and their Characterization

Over the last decade research on cancer stem cells (CSC) significantly contributed to a better understanding of tumor biology. Given their similarity to normal stem cells, i.e. self-renewal and pluripotency the need arises to develop robust protocols for the isolation and characterization of CSCs. As with other malignancies, hepatic tumors are composed of a heterogeneous population of cells including liver cancer stem cells (LCSC). Yet, a precise understanding of why stem cells become cancerous is still lacking. There is unmet need to develop robust protocols for the successful isolation of LCSCs from human tissue resection material as to assist in the development of molecular targeted therapies. Here we review the research progress made in the isolation and characterization of LCSCs by considering a wide range of cell surface markers and sorting methods, as applied to side populations, microsphere cultures and the gradient centrifugation method. We emphasize the different fluorescence activated cell sorting methods and the possibility to enrich LCSCs by immunomagnetic beads. We review the specificity of functional assays by considering ABCG transporter and ALDH1 enzyme activities and evaluate the in vivo tumorigenicity of LCSCs in highly sensitive bioassays. Finally, we evaluate different LCSC markers in association with viral and non-viral liver disease and explore the potential of novel drug delivery systems targeting CD133, EpCAM, CD13 and CD90 for the development of molecular targeted therapies. Graphical Abstract.

Reappraisal of the diagnostic value of alpha-fetoprotein for surveillance of HBV-related hepatocellular carcinoma in the era of antiviral therapy

This study was designed to explore if antiviral treatment influences the performance of serum alpha-fetoprotein (AFP) for hepatocellular carcinoma (HCC) among the high-risk chronic HBV-infected patients. A total of 5936 patients who had evidence of chronic HBV infection were enrolled from four independent centres in this retrospective study, including 1721 chronic hepatitis B (CHB), 2286 liver cirrhosis (LC), 798 HCC within Milan criteria and 1131 HCC beyond Milan criteria patients. Stratified by whether they received treatment or not, the patients were further divided into antiviral and non-antiviral groups. Then, the performance of AFP for discriminating HCC was evaluated. Patients receiving antivirals had significantly lower median levels of AFP compared with the non-antiviral patients (P < .001), and there were significantly less patients with abnormal AFP levels in antiviral groups (P < .001). Antiviral therapy improved the AUROCs of AFP for discriminating HCC within Milan criteria. When setting the cut-off values at 20 ng/mL and 100 ng/mL as surveillance and confirmatory tests respectively for HCC among patients receiving antiviral treatment, AFP exhibited a significantly higher sensitivity than those of 200 ng/mL and 400 ng/mL, which are currently recommended by some guidelines, without compromising specificity. Further analysis in antiviral patients revealed that serum AFP had better performance for discriminating HCC within Milan criteria in ALT ≤ 1ULN patients than that in ALT > 1ULN patients. In conclusion, in the era of antiviral therapy, serum AFP's surveillance performance was substantially improved for HCC within Milan criteria among the high-risk population of CHB and LC patients.

Differential Roles for Diploid and Polyploid Hepatocytes in Acute and Chronic Liver Injury

Hepatocytes are the primary functional cells of the liver that perform essential roles in homeostasis, regeneration, and injury. Most mammalian somatic cells are diploid and contain pairs of each chromosome, but there are also polyploid cells containing additional sets of chromosomes. Hepatocytes are among the best described polyploid cells, with polyploids comprising more than 25 and 90% of the hepatocyte population in humans and mice, respectively. Cellular and molecular mechanisms that regulate hepatic polyploidy have been uncovered, and in recent years, diploid and polyploid hepatocytes have been shown to perform specialized functions. Diploid hepatocytes accelerate liver regeneration induced by resection and may accelerate compensatory regeneration after acute injury. Polyploid hepatocytes protect the liver from tumor initiation in hepatocellular carcinoma and promote adaptation to tyrosinemia-induced chronic injury. This review describes how ploidy variations influence cellular activity and presents a model for context-specific functions for diploid and polyploid hepatocytes.

The Impact of Acute or Chronic Alcohol Intake on the NF-κB Signaling Pathway in Alcohol-Related Liver Disease

Ethanol misuse is frequently associated with a multitude of profound medical conditions, contributing to health-, individual- and social-related damage. A particularly dangerous threat from this classification is coined as alcoholic liver disease (ALD), a liver condition caused by prolonged alcohol overconsumption, involving several pathological stages induced by alcohol metabolic byproducts and sustained cellular intoxication. Molecular, pathological mechanisms of ALD principally root in the innate immunity system and are especially associated with enhanced functionality of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway. NF-κB is an interesting and convoluted DNA transcription regulator, promoting both anti-inflammatory and pro-inflammatory gene expression. Thus, the abundancy of studies in recent years underlines the importance of NF-κB in inflammatory responses and the mechanistic stimulation of inner molecular motifs within the factor components. Hereby, in the following review, we would like to put emphasis on the correlation between the NF-κB inflammation signaling pathway and ALD progression. We will provide the reader with the current knowledge regarding the chronic and acute alcohol consumption patterns, the molecular mechanisms of ALD development, the involvement of the NF-κB pathway and its enzymatic regulators. Therefore, we review various experimental in vitro and in vivo studies regarding the research on ALD, including the recent active compound treatments and the genetic modification approach. Furthermore, our investigation covers a few human studies.

In vitro differentiation effect of CCL4-induced liver injured mice serum on bone marrow-derived mesenchymal stem cells toward hepatocytes like cells

Liver dysfunction is a major health problem worldwide. Stem cells therapy has opened up new avenues for researches to treat liver diseases due to their multi lineage differentiation. As mesenchymal stem cells (MSCs) can be differentiated into hepatic lineages in the presence of different exogenous factors, the current study aimed to investigate the impact of carbon tetrachloride (CCl₄) induced liver injured mice serum on MSCs differentiation toward hepatocytes in vitro. Male Balb/c mice were treated for liver injury with CCl₄ as determined through biochemical tests spectrophotometrically and different growth factors (EGF, HGF) quantification through Sandwich ELISA in both normal and CCl₄-induced liver injured mice serum. Mice bone marrow derived-MSCs at second passage were treated with normal and CCl₄-induced liver injured mice serum. After 7 days, serum treated MSCs were investigated for hepatocytes like characteristics through RT-PCR. Serum biochemical tests (Bilirubin, ALT and ALP) and sandwich ELISA results of EGF and HGF showed marked increase in CCl₄ treated mice serum as compared to normal mice serum_. Periodic acid Schiff's staining and urea assay kit confirmed high level of glycogen storage and urea production in cells treated with CCl₄-induced liver injured mice serum. RT-PCR results of CCl₄-induced liver injured mice serum treated cells also showed expression of hepatic markers (Albumin, Cyto-8, Cyto-18, and Cyto-19). This study confirmed that CCl₄-induced liver injured serum treatment can differentiate MSCs into hepatocyte-like cells in vitro.

Cyclin-like proteins tip regenerative balance in the liver to favour cancer formation

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths worldwide. A variety of factors can contribute to the onset of this disease, including viral infection, obesity, alcohol abuse and non-alcoholic fatty liver disease (NAFLD). These stressors predominantly introduce chronic inflammation leading to liver cirrhosis and finally the onset of HCC; however, approximately 20% of HCC cases arise in the absence of cirrhosis via a poorly defined mechanism. The atypical cyclin-like protein Spy1 is capable of overriding cell cycle checkpoints, promoting proliferation and has been implicated in HCC. We hypothesize that Spy1 promotes sustained proliferation making the liver more susceptible to accumulation of deleterious mutations, leading to the development of non-cirrhotic HCC. We report for the first time that elevation of Spy1 within the liver of a transgenic mouse model leads to enhanced spontaneous liver tumourigenesis. We show that the abundance of Spy1 enhanced fat deposition within the liver and decreased the inflammatory response. Interestingly, Spy1 transgenic mice have a significant reduction in fibrosis and sustained rates of hepatocyte proliferation, and endogenous levels of Spy1 are downregulated during the normal fibrotic response. Our results provide support that abnormal regulation of Spy1 protein drives liver tumorigenesis in the absence of elevated fibrosis and, hence, may represent a potential mechanism behind non-cirrhotic HCC. This work may implicate Spy1 as a prognostic indicator and/or potential target in the treatment of diseases of the liver, such as HCC. The cyclin-like protein Spy1 enhances lipid deposition and reduces fibrosis in the liver. Spy1 also promotes increased hepatocyte proliferation and onset of non-cirrhotic hepatocellular carcinoma (HCC). Thus, Spy1 may be used as a potential target in the treatment of HCC.

Pharmacokinetic and Pharmacodynamic Properties of Cemdisiran, an RNAi Therapeutic Targeting Complement Component 5, in Healthy Subjects and Patients with Paroxysmal Nocturnal Hemoglobinuria

BACKGROUND

Cemdisiran, an N-acetylgalactosamine (GalNAc) conjugated RNA interference (RNAi) therapeutic, is currently under development for the treatment of complement-mediated diseases by suppressing liver production of complement 5 (C5) protein. This study was designed to evaluate the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of cemdisiran in healthy subjects and in patients with paroxysmal nocturnal hemoglobinuria (PNH) in order to support dose selection for late-stage clinical trials.

METHODS

Healthy volunteers (HVs; n = 32, including 12 Japanese subjects) were randomized (3:1) to receive single doses of subcutaneous cemdisiran (50-900 mg) or placebo, or repeat doses of subcutaneous cemdisiran (100-600 mg) or placebo weekly, biweekly, weekly/biweekly, or weekly/monthly for 5, 8, or 13 weeks (n = 24). Cemdisiran 200 or 400 mg was administered weekly in an open-label manner, for varying durations, as monotherapy in three eculizumab-naïve PNH patients or in combination with eculizumab in three PNH patients who were receiving stable label doses of eculizumab (900 or 1200 mg biweekly) before the start of the study. After the last dose of cemdisiran, patients were followed for safety and ongoing pharmacologic effects with the eculizumab regimen (600 or 900 mg every month).

RESULTS

In HVs, cemdisiran was rapidly converted to a major active metabolite, AS(N-2)3'-cemdisiran, both declining below the lower limit of quantification (LLOQ) in plasma within 48 h, and showing minimal renal excretion. AS(N-2)3'-cemdisiran exhibited more than dose-proportional PK. The C5 protein reductions were dose-dependent, with > 90% reduction of C5 protein beginning on days 21-28 and maintained for 10-13 months following single and biweekly doses of 600 mg. The dose-response relationship, described by an inhibitory sigmoid maximum effect (E_max) model, estimated half-maximal effective dose (ED₅₀) of 14.0 mg and maximum C5 reduction of 99% at 600 mg. The PK and PD were similar between Japanese and non-Japanese subjects, and PNH patients and HVs. One of 48 subjects tested transiently positive for antidrug antibody with low titer, with no impact on PK or PD. In PNH patients, C5 suppression by cemdisiran enabled effective inhibition of residual C5 levels with lower dose and/or dosing frequency of eculizumab, which was maintained for 6-10 months after the last dose of cemdisiran.

CONCLUSIONS

Consistent with the PK/PD properties of liver targeting GalNac conjugates, cemdisiran and AS(N-2)3'-cemdisiran plasma concentrations declined rapidly while showing rapid and robust C5 suppression maintained up to 13 months following single and multiple doses, which indicates long residence times of cemdisiran within hepatocytes. The long PD duration of action in liver, low immunogenicity and acceptable safety profiles enables low, infrequent SC dosing and support further evaluation of cemdisiran in complement-mediated diseases as monotherapy or in combination with a C5 inhibitor antibody.

CLINICAL TRIAL REGISTRATION NO

NCT02352493.

Organ-on-a-chip platforms for accelerating the evaluation of nanomedicine

Nanomedicine involves the use of engineered nanoscale materials in an extensive range of diagnostic and therapeutic applications and can be applied to the treatment of many diseases. Despite the rapid progress and tremendous potential of nanomedicine in the past decades, the clinical translational process is still quite slow, owing to the difficulty in understanding, evaluating, and predicting nanomaterial behaviors within the complex environment of human beings. Microfluidics-based organ-on-a-chip (Organ Chip) techniques offer a promising way to resolve these challenges. Sophisticatedly designed Organ Chip enable in vitro simulation of the in vivo microenvironments, thus providing robust platforms for evaluating nanomedicine. Herein, we review recent developments and achievements in Organ Chip models for nanomedicine evaluations, categorized into seven broad sections based on the target organ systems: respiratory, digestive, lymphatic, excretory, nervous, and vascular, as well as coverage on applications relating to cancer. We conclude by providing our perspectives on the challenges and potential future directions for applications of Organ Chip in nanomedicine.

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Microfluidics-based organ-on-a-chip (Organ Chip) techniques offer a promising way to understand, evaluate, and predict nanomedicine behaviors within the complex environment.

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Organ Chip models for nanomedicine evaluations are categorized into seven broad sections based on the targeted body systems.

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Limitations, challenges, and perspectives of Organ Chip for accelerating the assessment of nanomedicine are discussed, respectively.