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Cell-death-inducing DNA fragmentation factor-alpha (DFFA)-like effector b (CIDEB) was first identified as an apoptosis-inducing protein. Further research revealed a pivotal role in lipid metabolism, regulating very-low-density lipoprotein (VLDL), lipid droplets (LD), sterol response element-binding protein (SREBP), and chylomicrons. Recent studies have uncovered that rare germline variants in CIDEB protect against liver diseases, including MAFLD, cirrhosis, and viral hepatitis. Furthermore, CIDEB influences steps of the hepatitis C virus (HCV) replication cycle. This review summarizes the current knowledge about CIDEB’s roles in apoptosis, lipid metabolism, and viral hepatitis, and highlights its critical role in liver diseases.

Nicotinamide adenine dinucleotide (NAD + ), a coenzyme for more than 500 enzymes, plays a central role in energy production, metabolism, cellular signaling, and DNA repair. Until recently, NAD + was primarily considered to be an intracellular molecule (iNAD + ), however, its extracellular species (eNAD + ) has recently been discovered and has since been associated with a multitude of pathological conditions. Therefore, accurate quantification of eNAD + in bodily fluids such as plasma is paramount to answer important research questions. In order to create a clinically meaningful and reliable quantitation method, we analyzed the relationship of cell lysis, routine clinical laboratory parameters, blood collection techniques, and pre-analytical processing steps with measured plasma eNAD + concentrations. Initially, NAD + levels were assessed both intracellularly and extracellularly. Intriguingly, the concentration of eNAD + in plasma was found to be approximately 500 times lower than iNAD + in peripheral blood mononuclear cells (0.253 ± 0.02 μM vs. 131.8 ± 27.4 μM, p  = 0.007, respectively). This stark contrast suggests that cellular damage or cell lysis could potentially affect the levels of eNAD + in plasma. However, systemic lactate dehydrogenase in patient plasma, a marker of cell damage, did not significantly correlate with eNAD + ( n  = 33; r  = −0.397; p  = 0.102). Furthermore, eNAD + was negatively correlated with increasing c-reactive protein (CRP, n  = 33; r  = −0.451; p  = 0.020), while eNAD + was positively correlated with increasing hemoglobin ( n  = 33; r  = 0.482; p  = 0.005). Next, variations in blood drawing, sample handling and pre-analytical processes were examined. Sample storage durations at 4°C (0–120 min), temperature (0° to 25°C), cannula sizes for blood collection and tourniquet times (0 – 120 s) had no statistically significant effect on eNAD + ( p  > 0.05). On the other hand, prolonged centrifugation (> 5 min) and a faster braking mode of the centrifuge rotor (< 4 min) resulted in a significant decrease in eNAD + levels ( p  < 0.05). Taken together, CRP and hemoglobin appeared to be mildly correlated with eNAD + levels whereas cell damage was not correlated significantly to eNAD + levels. The blood drawing trial did not show any influence on eNAD + , in contrast, the preanalytical steps need to be standardized for accurate eNAD + measurement. This work paves the way towards robust eNAD + measurements, for use in future clinical and translational research, and provides an optimized hands-on protocol for reliable eNAD + quantification in plasma.

Background Since autologous veins are unavailable when needed in more than 20% of cases in vascular surgery, the production of personalized biological vascular grafts for implantation has become crucial. Surface modification of decellularized xenogeneic grafts with vascular cells to achieve physiological luminal coverage and eventually thromboresistance is an important prerequisite for implantation. However, ex vivo thrombogenicity testing remains a neglected area in the field of tissue engineering of vascular grafts due to a multifold of reasons. Methods After seeding decellularized bovine carotid arteries with human endothelial progenitor cells and umbilical cord-derived mesenchymal stem cells, luminal endothelial cell coverage (LECC) was correlated with glucose and lactate levels on the cell supernatant. Then a closed loop whole blood perfusion system was designed. Recellularized grafts with a LECC > 50% and decellularized vascular grafts were perfused with human whole blood for 2 h. Hemolysis and complete blood count evaluation was performed on an hourly basis, followed by histological and immunohistochemical analysis. Results While whole blood perfusion of decellularized grafts significantly reduced platelet counts, platelet depletion from blood resulting from binding to re-endothelialized grafts was insignificant ( p  = 0.7284). Moreover, macroscopic evaluation revealed thrombus formation only in the lumen of unseeded grafts and histological characterization revealed lack of CD41 positive platelets in recellularized grafts, thus confirming their thromboresistance. Conclusion In the present study we were able to demonstrate the effect of surface modification of vascular grafts in their thromboresistance in an ex vivo whole blood perfusion system. To our knowledge, this is the first study to expose engineered vascular grafts to human whole blood, recirculating at high flow rates, immediately after seeding.

The only definitive therapy for end‐stage liver disease is whole‐organ transplantation. The success of this intervention is severely limited by the complexity of the surgery, the cost of patient care, the need for long‐term immunosuppression, and the shortage of donor organs. In rodents and humans, end‐stage degeneration of hepatocyte function is associated with disruption of the liver‐specific transcriptional network and a nearly complete loss of promoter P1‐driven hepatocyte nuclear factor 4‐alpha (P1‐HNF4α) activity. Re‐expression of HNF4α2, the predominant P1‐HNF4α, reinstates the transcriptional network, normalizes the genes important for hepatocyte function, and reverses liver failure in rodents. In this study, we tested the effectiveness of supplementary expression of human HNF4α2 messenger RNA (mRNA) in primary human hepatocytes isolated from explanted livers of patients who underwent transplant for end‐stage irreversibly decompensated liver failure (Child‐Pugh B, C) resulting from alcohol‐mediated cirrhosis and nonalcoholic steatohepatitis. Re‐expression of HNF4α2 in decompensated cirrhotic human hepatocytes corrects the disrupted transcriptional network and normalizes the expression of genes important for hepatocyte function, improving liver‐specific protein expression. End‐stage liver disease in humans is associated with both loss of P1‐HNF4α expression and failure of its localization to the nucleus. We found that while HNF4α2 re‐expression increased the amount of P1‐HNF4α protein in hepatocytes, it did not alter the ability of hepatocytes to localize P1‐HNF4α to their nuclei. Conclusion: Re‐expression of HNF4α2 mRNA in livers of patients with end‐stage disease may be an effective therapy for terminal liver failure that would circumvent the need for organ transplantation. The efficacy of this strategy may be enhanced by discovering the cause for loss of nuclear P1‐HNF4α localization in end‐stage cirrhosis, a process not found in rodent studies. Re‐expression of HNF4α2 in decompensated cirrhotic human hepatocytes corrects the disrupted transcriptional network and normalizes the expression of genes important for hepatocyte function, improving liver‐specific protein expression. mRNA‐mediated re‐expression of HNF4α2 in the livers of patients with the end‐stage disease may be an effective therapy for terminal liver failure that would circumvent the need for organ transplantation.

The initial creation of human‐induced pluripotent stem cells (iPSCs) set the foundation for the future of regenerative medicine. Human iPSCs can be differentiated into a variety of cell types in order to study normal and pathological molecular mechanisms. Currently, there are well‐defined protocols for the differentiation, characterization, and establishment of functionality in human iPSC‐derived hepatocytes (iHep) and iPSC‐derived cholangiocytes (iCho). Electrophysiological study on chloride ion efflux channel activity in iHep and iCho cells has not been previously reported. We generated iHep and iCho cells and characterized them based on hepatocyte‐specific and cholangiocyte‐specific markers. The relevant transmembrane channels were selected: cystic fibrosis transmembrane conductance regulator, leucine rich repeat‐containing 8 subunit A, and transmembrane member 16 subunit A. To measure the activity in these channels, we used whole‐cell patch‐clamp techniques with a standard intracellular and extracellular solution. Our iHep and iCho cells demonstrated definitive activity in the selected transmembrane channels, and this approach may become an important tool for investigating human liver biology of cholestatic diseases. Transmembrane Channel Activity in Human Hepatocytes and Cholangiocytes Derived from Induced Pluripotent Stem Cells.

Hepatocyte nuclear factor 4 alpha (HNF4α) is a transcription factor that plays a critical role in hepatocyte function, and HNF4α‐based reprogramming corrects terminal liver failure in rats with chronic liver disease. In the livers of patients with advanced cirrhosis, HNF4α RNA expression levels decrease as hepatic function deteriorates, and protein expression is found in the cytoplasm. These findings could explain impaired hepatic function in patients with degenerative liver disease. In this study, we analyzed HNF4α localization and the pathways involved in post‐translational modification of HNF4α in human hepatocytes from patients with decompensated liver function. RNA‐sequencing analysis revealed that AKT‐related pathways, specifically phospho‐AKT, is down‐regulated in cirrhotic hepatocytes from patients with terminal failure, in whom nuclear levels of HNF4α were significantly reduced, and cytoplasmic expression of HNF4α was increased. cMET was also significantly reduced in failing hepatocytes. Moreover, metabolic profiling showed a glycolytic phenotype in failing human hepatocytes. The contribution of cMET and phospho‐AKT to nuclear localization of HNF4α was confirmed using Spearman's rank correlation test and pathway analysis, and further correlated with hepatic dysfunction by principal component analysis. HNF4α acetylation, a posttranslational modification important for nuclear retention, was also significantly reduced in failing human hepatocytes when compared with normal controls. Conclusion: These results suggest that the alterations in the cMET‐AKT pathway directly correlate with HNF4α localization and level of hepatocyte dysfunction. This study suggests that manipulation of HNF4α and pathways involved in HNF4α posttranslational modification may restore hepatocyte function in patients with terminal liver failure. Although drug induced liver injury (DILI) is a rare clinical event, it carries significant morbidity and mortality, leaving it as the leading cause of acute liver failure in the United States. It is one of the most challenging diagnoses encountered by gastroenterologists. DILI is also the most common single adverse event that has led to withdrawal of drugs from the marketplace, drug attrition and failure of implicated drugs to obtain FDA approval. The development of various drug injury networks have played a vital role in expanding our knowledge regarding drug, herbal and dietary supplement related liver injury. In this review, we discuss what defines liver injury, epidemiology of DILI, it's biochemical and pathologic patterns, and management.

As diet and lifestyle have changed, fatty liver disease (FLD) has become more and more prevalent. Many genetic risk factors, such as variants of PNPLA3, TM6SF2, GCKR, and MBOAT7, have previously been uncovered via genome wide association studies (GWAS) to be associated with FLD. In 2018, a genetic variant (rs72613567, T > TA) of hydroxysteroid 17-β dehydrogenase family 13 (HSD17B13) was first associated with a lower risk of developing alcoholic liver disease and non-alcoholic fatty liver disease (NAFLD) in minor allele carriers. Other HSD17B13 variants were also later linked with either lower inflammation scores among NAFLD patients or protection against NAFLD (rs6834314, A > G and rs9992651, G > A) respectively. HSD17B13 is a lipid droplet-associated protein, but its function is still ambiguous. Compared to the other genetic variants that increase risk for FLD, HSD17B13 variants serve a protective role, making this gene a potential therapeutic target. However, the mechanism by which these variants reduce the risk of developing FLD is still unclear. Because studies in cell lines and mouse models have produced conflicting results, human liver tissue modeling using induced pluripotent stem cells may be the best way to move forward and solve this mystery.

Genetic variants in lipid metabolism influence the risk of developing metabolic dysfunction-associated steatotic liver disease (MASLD), cirrhosis, and end-stage liver disease (ESLD). The mechanisms by which these variants drive disease are poorly understood. Because of the PNPLA3-I148M variant's strong correlation with all stages of the MASLD spectrum and the lack of tractable therapeutic targets, we sought to understand its impact on cellular function and liver metabolism. Primary human hepatocytes (HAHs) and induced pluripotent stem cell-derived (iPSC-derived) hepatocytes (iHeps) from healthy individuals possessing the PNPLA3-I148M mutation were characterized for changes in lipid metabolism, cellular stress, and survival. Using lipidomics, metabolomics, stable isotope tracing, and flux propensity analysis, we created a comprehensive metabolic profile of the changes associated with the PNPLA3-I148M variant. Functional analysis showed that the presence of the PNPLA3-I148M variant increased endoplasmic reticulum stress, mitochondrial dysfunction, and peroxisomal β-oxidation, ultimately leading to cell death via ferroptosis. Nutritional interventions, ferroptosis-specific inhibitors, and genetic approaches modulating GPX4 activity in PNPLA3-I148M HAHs and iHeps decreased programmed cell death. Our findings indicate that therapies targeting ferroptosis in patients carrying the PNPLA3-I148M variant could affect the development of MASLD and ESLD and highlight the utility of iPSC-based models for the study of genetic contributions to hepatic disorders.

Drug discovery for multifactorial diseases like metabolic dysfunction-associated steatotic liver disease (MASLD) remains challenging due to inadequate models and untargeted drug screenings. We combined stem-cell-based modeling with computational drug predictions identifying flavin pathways as therapeutic targets in MASLD. For disease stage-specific discovery, we established a MASLD testing model, compounding metabolic triggers to intensify mitochondrial crisis. In vitro injuries included adipo- and myokines, immune cell co-culture, and genomic risk factors. Benchmarking experiments revealed similarities with advanced human MASLD. To query therapeutic compounds, protein-protein-interaction networks, weighted gene co-expression, and knowledge graph-based analyses independently predicted flavin adenine dinucleotide (FAD) as an anti-MASLD factor. Dysregulated flavoproteomes in vitro and in vivo–in pediatric and adult MASLD patients– supported our flavin network-focused strategy. We established therapeutic FAD concentrations to mitigate metabolic injury and fibro-inflammation in human multicellular liver organoids and other assays. We enhanced therapeutic FAD effects through genetic mitochondrial biogenic augmentation and identified orally available flavo-active compounds—including Aspirin—restoring mitochondrial respiration. Our study demonstrates how integrating stem cell-derived disease modeling with computed drug predictions can expedite therapeutic discovery.