bims-faldev 2024-06-23 papers

Cell Biochem Funct. 2024 Jun;42(4): e4077

Extracellular vesicles originating from steatotic hepatocytes promote hepatic stellate cell senescence via AKT/mTOR signaling.

Zongmei Wu, Mengmeng Xia, Junyu Wang, Magnolia Martinez Aguilar, Manon Buist-Homan, Han Moshage.

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is increasing rapidly due to the obesity epidemic. In the inflammatory stages of MASLD (MASH), activation of hepatic stellate cells (HSCs) leads to initiation and progression of liver fibrosis. Extracellular vesicles (EVs) are released from all cell types and play an important role in intercellular communication. However, the role of EVs released from hepatocytes in the context of MASLD is largely unknown. Therefore, the present study aimed to investigate the role of EVs derived from both normal and steatotic (free fatty acid-treated) hepatocytes on the phenotype of HSCs via the senescence pathway. Primary rat hepatocytes were treated with free fatty acids (FFAs: oleic acid and palmitic acid). EVs were collected by ultracentrifugation. EVs markers and HSCs activation and senescence markers were assessed by Western blot analysis, qPCR and cytochemistry. Reactive oxygen species (ROS) production was assessed by fluorescence assay. RNA profiles of EVs were evaluated by sequencing. We found that EVs from hepatocytes treated with FFAs (FFA-EVs) inhibit collagen type 1 and α-smooth muscle actin expression, increase the production of ROS and the expression of senescence markers (IL-6, IL-1β, p21 and senescence-associated β-galactosidase activity) in early activating HSCs via the AKT-mTOR pathway. Sequencing showed differentially enriched RNA species between the EVs groups. In conclusion, EVs from FFA-treated hepatocytes inhibit HSC activation by inducing senescence via the AKT-mTOR signaling pathway. Determining the components in EVs from steatotic hepatocytes that induce HSC senescence may lead to the identification of novel targets for intervention in the treatment of MASLD in the future.

Keywords: AKT/mTOR signaling; MASLD; extracellular vesicles; hepatic stellate cells; miRNAs; senescence

DOI: https://doi.org/10.1002/cbf.4077

United European Gastroenterol J. 2024 Jun 18.

Fibroblast growth factor 21 is a hepatokine involved in MASLD progression.

AIM: We aimed to assess the role of FGF21 in metabolic dysfunction-associated steatotic liver disease (MASLD) at a multi-scale level.
METHODS: We used human MASLD pathology samples for FGF21 gene expression analyses (qPCR and RNAseq), serum to measure circulating FGF21 levels and DNA for genotyping the FGF21 rs838133 variant in both estimation and validation cohorts. A hepatocyte-derived cell line was exposed to free fatty acids at different timepoints. Finally, C57BL/6J mice were fed a high-fat and choline-deficient diet (CDA-HFD) for 16 weeks to assess hepatic FGF21 protein expression and FGF21 levels by ELISA.
RESULTS: A significant upregulation in FGF21 mRNA expression was observed in the liver analysed by both qPCR (fold change 5.32 ± 5.25 vs. 0.59 ± 0.66; p = 0.017) and RNA-Seq (3.5 fold; FDR: 0.006; p < 0.0001) in MASLD patients vs. controls. Circulating levels of FGF21 were increased in patients with steatohepatitis vs. bland steatosis (386.6 ± 328.9 vs. 297.9 ± 231.5 pg/mL; p = 0.009). Besides, sex, age, A-allele from FGF21, GG genotype from PNPLA3, ALT, type 2 diabetes mellitus and BMI were independently associated with MASH and significant fibrosis in both estimation and validation cohorts. In vitro exposure of Huh7.5 cells to high concentrations of free fatty acids (FFAs) resulted in overexpression of FGF21 (p < 0.001). Finally, Circulating FGF21 levels and hepatic FGF21 expression were found to be significantly increased (p < 0.001) in animals under CDA-HFD.
CONCLUSIONS: Hepatic and circulating FGF21 expression was increased in MASH patients, in Huh7.5 cells under FFAs and in CDA-HFD animals. The A-allele from the rs838133 variant was also associated with an increased risk of steatohepatitis and significant and advanced fibrosis in MASLD patients.

Keywords: FGF21; MASH; MASLD; NAFLD; NASH; fibroblast growth factor 21; gene expression; hepatokine; metabolic syndrome; steatohepatitis

DOI: https://doi.org/10.1002/ueg2.12534

Trends Mol Med. 2024 Jun 17. pii: S1471-4914(24)00135-7. [Epub ahead of print]

Sexual dimorphism of metabolic dysfunction-associated steatotic liver disease.

Alessandro Cherubini, Sara Della Torre, Serena Pelusi, Luca Valenti.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver condition. MASLD is a sexually dimorphic condition, with its development and progression influenced by sex chromosomes and hormones. Estrogens typically protect against, whereas androgens promote, MASLD. Therapeutic approaches for a sex-specific personalized medicine include estrogen replacement, androgen blockers, and novel drugs targeting hormonal pathways. However, the interactions between hormonal factors and inherited genetic variation impacts MASLD risk, necessitating more tailored therapies. Understanding sex disparities and the role of estrogens could improve MASLD interventions and management, whereas clinical trials addressing sex differences are crucial for advancing personalized treatment. This review explores the underappreciated impact of sexual dimorphism in MASLD and discusses the potential therapeutic application of sex-related hormones.

Keywords: MASLD; NAFLD; estrogen receptor; fatty liver disease; hormones

DOI: https://doi.org/10.1016/j.molmed.2024.05.013

Int J Mol Sci. 2024 Jun 04. pii: 6193. [Epub ahead of print]25(11):

Longitudinal Analysis of Mitochondrial Function in a Choline-Deficient L-Amino Acid-Defined High-Fat Diet-Induced Metabolic Dysfunction-Associated Steatohepatitis Mouse Model.

Akiko Yamada, Akira Watanabe, Atsushi Nara, Naozumi Ishimaru, Kosuke Maeda, Yusuke Ido, Kazumasa Kotake, Masatake Asano, Yasuo Shinohara, Takenori Yamamoto.

Metabolic dysfunction-associated fatty liver disease (MAFLD) is one of the most common chronic liver diseases worldwide. Some patients with MAFLD develop metabolic dysfunction-associated steatohepatitis (MASH), which can lead to severe liver fibrosis. However, the molecular mechanisms underlying this progression remain unknown, and no effective treatment for MASH has been developed so far. In this study, we performed a longitudinal detailed analysis of mitochondria in the livers of choline-deficient, methionine-defined, high-fat-diet (CDAHFD)-fed mice, which exhibited a MASH-like pathology. We found that FoF1-ATPase activity began to decrease in the mitochondria of CDAHFD-fed mice prior to alterations in the activity of mitochondrial respiratory chain complex, almost at the time of onset of liver fibrosis. In addition, the decrease in FoF1-ATPase activity coincided with the accelerated opening of the mitochondrial permeability transition pore (PTP), for which FoF1-ATPase might be a major component or regulator. As fibrosis progressed, mitochondrial permeability transition (PT) induced in CDAHFD-fed mice became less sensitive to cyclosporine A, a specific PT inhibitor. These results suggest that episodes of fibrosis might be related to the disruption of mitochondrial function via PTP opening, which is triggered by functional changes in FoF1-ATPase. These novel findings could help elucidate the pathogenesis of MASH and lead to the development of new therapeutic strategies.

Keywords: FoF1–ATPase; liver fibrosis; metabolic dysfunction-associated steatohepatitis; mitochondria; permeability transition

DOI: https://doi.org/10.3390/ijms25116193

Int J Mol Sci. 2024 May 29. pii: 5965. [Epub ahead of print]25(11):

Predicting Non-Alcoholic Steatohepatitis: A Lipidomics-Driven Machine Learning Approach.

Thomai Mouskeftara, Georgios Kalopitas, Theodoros Liapikos, Konstantinos Arvanitakis, Georgios Germanidis, Helen Gika.

Nonalcoholic fatty liver disease (NAFLD), nowadays the most prevalent chronic liver disease in Western countries, is characterized by a variable phenotype ranging from steatosis to nonalcoholic steatohepatitis (NASH). Intracellular lipid accumulation is considered the hallmark of NAFLD and is associated with lipotoxicity and inflammation, as well as increased oxidative stress levels. In this study, a lipidomic approach was used to investigate the plasma lipidome of 12 NASH patients, 10 Nonalcoholic Fatty Liver (NAFL) patients, and 15 healthy controls, revealing significant alterations in lipid classes, such as glycerolipids and glycerophospholipids, as well as fatty acid compositions in the context of steatosis and steatohepatitis. A machine learning XGBoost algorithm identified a panel of 15 plasma biomarkers, including HOMA-IR, BMI, platelets count, LDL-c, ferritin, AST, FA 12:0, FA 18:3 ω3, FA 20:4 ω6/FA 20:5 ω3, CAR 4:0, LPC 20:4, LPC O-16:1, LPE 18:0, DG 18:1_18:2, and CE 20:4 for predicting steatohepatitis. This research offers insights into the connection between imbalanced lipid metabolism and the formation and progression of NAFL D, while also supporting previous research findings. Future studies on lipid metabolism could lead to new therapeutic approaches and enhanced risk assessment methods, as the shift from isolated steatosis to NASH is currently poorly understood.

Keywords: machine learning; non-alcoholic fatty liver disease; plasma; untargeted lipidomics

DOI: https://doi.org/10.3390/ijms25115965

Molecules. 2024 Jun 03. pii: 2630. [Epub ahead of print]29(11):

Kaempferol Alleviates Hepatic Injury in Nonalcoholic Steatohepatitis (NASH) by Suppressing Neutrophil-Mediated NLRP3-ASC/TMS1-Caspase 3 Signaling.

He Yang, Dandan Li, Guolan Gao.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is a significant hepatic condition that has gained worldwide attention. Kaempferol (Kae), renowned for its diverse biological activities, including anti-inflammatory, antioxidant, anti-aging, and cardio-protective properties, has emerged as a potential therapeutic candidate for non-alcoholic steatohepatitis (NASH). Despite its promising therapeutic potential, the precise underlying mechanism of Kae's beneficial effects in NASH remains unclear. Therefore, this study aims to clarify the mechanism by conducting comprehensive in vivo and in vitro experiments.
RESULTS: In this study, a murine model of non-alcoholic steatohepatitis (NASH) was established by feeding C57BL/6 female mice a high-fat diet for 12 weeks. Kaempferol (Kae) was investigated for its ability to modulate systemic inflammatory responses and lipid metabolism in this model (20 mg/kg per day). Notably, Kae significantly reduced the expression of NLRP3-ASC/TMS1-Caspase 3, a crucial mediator of liver tissue inflammation. Additionally, in a HepG2 cell model induced with palmitic acid/oleic acid (PA/OA) to mimic NASH conditions, Kae demonstrated the capacity to decrease lipid droplet accumulation and downregulate the expression of NLRP3-ASC/TMS1-Caspase 3 (20 µM and the final concentration to 20 nM). These findings suggest that Kae may hold therapeutic potential in the treatment of NASH by targeting inflammatory and metabolic pathways.
CONCLUSIONS: These findings suggest that kaempferol holds potential as a promising therapeutic intervention for ameliorating non-alcoholic fatty liver disease (NAFLD).

Keywords: ASC/TMS1; Caspase 3; NASH; NLRP3; apoptosis

DOI: https://doi.org/10.3390/molecules29112630

JHEP Rep. 2024 Jun;6(6): 101073

Glycogen synthase kinase 3 activity enhances liver inflammation in MASH.

Background & Aims: Metabolic dysfunction-associated steatohepatitis (MASH) is characterized by excessive circulating toxic lipids, hepatic steatosis, and liver inflammation. Monocyte adhesion to liver sinusoidal endothelial cells (LSECs) and transendothelial migration (TEM) are crucial in the inflammatory process. Under lipotoxic stress, LSECs develop a proinflammatory phenotype known as endotheliopathy. However, mediators of endotheliopathy remain unclear.
Methods: Primary mouse LSECs isolated from C57BL/6J mice fed chow or MASH-inducing diets rich in fat, fructose, and cholesterol (FFC) were subjected to multi-omics profiling. Mice with established MASH resulting from a choline-deficient high-fat diet (CDHFD) or FFC diet were also treated with two structurally distinct GSK3 inhibitors (LY2090314 and elraglusib [9-ING-41]).
Results: Integrated pathway analysis of the mouse LSEC proteome and transcriptome indicated that leukocyte TEM and focal adhesion were the major pathways altered in MASH. Kinome profiling of the LSEC phosphoproteome identified glycogen synthase kinase (GSK)-3β as the major kinase hub in MASH. GSK3β-activating phosphorylation was increased in primary human LSECs treated with the toxic lipid palmitate and in human MASH. Palmitate upregulated the expression of C-X-C motif chemokine ligand 2, intracellular adhesion molecule 1, and phosphorylated focal adhesion kinase, via a GSK3-dependent mechanism. Congruently, the adhesive and transendothelial migratory capacities of primary human neutrophils and THP-1 monocytes through the LSEC monolayer under lipotoxic stress were reduced by GSK3 inhibition. Treatment with the GSK3 inhibitors LY2090314 and elraglusib ameliorated liver inflammation, injury, and fibrosis in FFC- and CDHFD-fed mice, respectively. Immunophenotyping using cytometry by mass cytometry by time of flight of intrahepatic leukocytes from CDHFD-fed mice treated with elraglusib showed reduced infiltration of proinflammatory monocyte-derived macrophages and monocyte-derived dendritic cells.
Conclusion: GSK3 inhibition attenuates lipotoxicity-induced LSEC endotheliopathy and could serve as a potential therapeutic strategy for treating human MASH.
Impact and Implications: LSECs under lipotoxic stress in MASH develop a proinflammatory phenotype known as endotheliopathy, with obscure mediators and functional outcomes. The current study identified GSK3 as the major driver of LSEC endotheliopathy, examined its pathogenic role in myeloid cell-associated liver inflammation, and defined the therapeutic efficacy of pharmacological GSK3 inhibitors in murine MASH. This study provides preclinical data for the future investigation of GSK3 pharmacological inhibitors in human MASH. The results of this study are important to hepatologists, vascular biologists, and investigators studying the mechanisms of inflammatory liver disease and MASH, as well as those interested in drug development.

Keywords: Adhesion; Chemokines; Glycogen synthase kinase 3 (GSK3); Inflammation; Liver fibrosis; Liver sinusoidal endothelial cells (LSEC); Metabolic dysfunction associated steatohepatitis (MASH); Migration; Myeloid cells; Non-alcoholic steatohepatitis (NASH)

DOI: https://doi.org/10.1016/j.jhepr.2024.101073