RESUMO
BACKGROUND: Fatty liver disease is a metabolic disorder that recently has been classified into two categories: metabolic dysfunction-associated fatty liver disease (MAFLD) and non-MAFLD. TGF-ß signaling pathway is likely a significant factor in the pathogenesis of this condition, exerting its effects through its downstream signaling proteins, Smad2/3. Accordingly, this study aimed to investigate the TGF-ß signaling pathway in the white blood cells (WBCs) of patients with MAFLD compared to those with non-MAFLD and control groups. METHODS AND RESULTS: In this study, 41 patients with fatty liver were evaluated, comprising 22 patients with MAFLD and 19 patients with non-MAFLD, and compared to 22 healthy controls. Gene expression of TGF-ß1, TGF-ß3, and CTGF were quantified using qRT-PCR, and the protein expressions of Smad2/3 and P-Smad2/3 were analyzed using western blotting. Gene expression analysis revealed a significant decrease in the gene expressions of the TGF-ß1 and TGF-ß3 and an increase in CTGF gene expression in patients with MAFLD and non-MAFLD compared to the control group. Notably, the Smad2/3 protein expression was significantly higher in the non-MAFLD group compared to the control group (P < 0.05). On the other hand, the P-smad2/3 protein expression was significantly elevated in the MAFLD group compared to the control group (P < 0.001). CONCLUSIONS: TGF-ß signaling pathway in WBCs of patients with fatty liver are affected by a complex signaling pathway. However, metabolic factors most probably affect TGF-ß1 gene expression and its downstream signaling proteins more than TGF-ß3.
Assuntos
Fator de Crescimento do Tecido Conjuntivo , Transdução de Sinais , Proteína Smad2 , Proteína Smad3 , Fator de Crescimento Transformador beta1 , Humanos , Masculino , Estudos de Casos e Controles , Feminino , Pessoa de Meia-Idade , Adulto , Proteína Smad2/metabolismo , Proteína Smad2/genética , Proteína Smad3/metabolismo , Proteína Smad3/genética , Fator de Crescimento do Tecido Conjuntivo/genética , Fator de Crescimento do Tecido Conjuntivo/metabolismo , Fator de Crescimento Transformador beta1/metabolismo , Fator de Crescimento Transformador beta1/genética , Fígado Gorduroso/metabolismo , Fígado Gorduroso/genética , Fator de Crescimento Transformador beta/metabolismo , Fator de Crescimento Transformador beta/genética , Proteínas Smad/metabolismo , Proteínas Smad/genética , Hepatopatia Gordurosa não Alcoólica/metabolismo , Hepatopatia Gordurosa não Alcoólica/genética , Fator de Crescimento Transformador beta3/metabolismo , Fator de Crescimento Transformador beta3/genética , Regulação da Expressão GênicaRESUMO
BACKGROUND: Abnormal lipid deposition is an important driver of the progression of metabolic dysfunction-associated steatotic liver disease (MASLD). MicroRNA-411-5p (miR-411-5p) and eukaryotic translation initiation factor 4γ2 (EIF4G2) are related to abnormal lipid deposition, but the specific mechanism is unknown. METHODS: A high-fat, high-cholesterol diet (HFHCD) and a choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD) and a high-fructose diet (HFrD) were used to establish MASLD rat and mouse models, respectively. MiR-411-5p agomir and mimic were used to upregulate the miR-411-5p in vivo and in vitro, respectively. Adeno-associated virus type 8 (AAV8) carrying EIF4G2 short hairpin RNA (shRNA) and small interfering RNA (siRNA) were used to downregulate the EIF4G2 expression in vivo and in vitro, respectively. Liver histopathological analysis, Biochemical analysis and other experiments were used to explore the functions of miR-411-5p and EIF4G2. RESULTS: MiR-411-5p was decreased in both MASLD rats and mice, and was negatively correlated with liver triglycerides and serum alanine transaminase (ALT) and aspartate transaminase (AST) levels. Upregulation of miR-411-5p alleviated liver lipid deposition and hepatocellular steatosis. Moreover, miR-411-5p targeted and downregulated EIF4G2. Downregulation of EIF4G2 not only reduced liver triglycerides and serum ALT and AST levels in MASLD model, but also alleviated lipid deposition. Notably, upregulation of miR-411-5p and downregulation of EIF4G2 led to the reduction of forkhead box class O3 (FOXO3) and inhibited the expression of sterol regulatory-element binding protein 1 (SREBP1), acetyl-CoA carboxylase 1 (ACC1) and fatty acid synthase (FASN), thereby reducing fatty acid synthesis. CONCLUSIONS: Upregulation of miR-411-5p inhibits EIF4G2 to reduce the FOXO3 expression, thereby reducing fatty acid synthesis and alleviating abnormal lipid deposition in MASLD.
Assuntos
Proteína Forkhead Box O3 , Metabolismo dos Lipídeos , MicroRNAs , Animais , MicroRNAs/genética , MicroRNAs/metabolismo , Camundongos , Masculino , Ratos , Metabolismo dos Lipídeos/genética , Proteína Forkhead Box O3/metabolismo , Proteína Forkhead Box O3/genética , Fator de Iniciação Eucariótico 4G/metabolismo , Fator de Iniciação Eucariótico 4G/genética , Camundongos Endogâmicos C57BL , Humanos , Fígado Gorduroso/metabolismo , Fígado Gorduroso/patologia , Fígado Gorduroso/genética , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Ratos Sprague-Dawley , Fígado/metabolismo , Fígado/patologiaRESUMO
Research on G protein-coupled receptor 75 (GPR75) in metabolic dysfunction-related steatosis liver disease (MASLD) reveals its potential role in regulating body weight and energy balance. Loss-of-function mutations in the GPR75 gene are significantly associated with lower body mass index and reduced body weight. Studies demonstrate that GPR75 knockout mice exhibit lower fasting blood glucose levels, improved glucose homeostasis, and significant prevention of high-fat diet-induced MASLD. The absence of GPR75 reduces fat accumulation by beneficially altering energy balance rather than restricting adipose tissue expansion. Moreover, female GPR75 knockout mice show greater protection against lipid accumulation on a high-fat diet compared to males, potentially attributed to higher physical activity and energy expenditure. However, current research primarily relies on mouse models, and its applicability to humans requires further validation. Future studies should explore the role of GPR75 across diverse populations, its clinical potential, and delve into its specific mechanisms and interactions with other metabolic pathways. Ultimately, targeted therapies based on GPR75 could offer novel strategies for the prevention and treatment of MASLD and other metabolic disorders.
Assuntos
Metabolismo Energético , Receptores Acoplados a Proteínas G , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Animais , Humanos , Metabolismo Energético/genética , Camundongos , Camundongos Knockout , Dieta Hiperlipídica/efeitos adversos , Fígado Gorduroso/genética , Fígado Gorduroso/metabolismo , Fígado Gorduroso/patologia , Feminino , Modelos Animais de Doenças , Masculino , Metabolismo dos Lipídeos/genéticaRESUMO
BACKGROUND: Recent studies have suggested an association between H. pylori and metabolic-disfunction associated fatty liver disease (MASLD). However, epidemiologic studies have yielded inconsistent results. We aim to evaluate the association of H. pylori and G-allele PNPLA3 in MASLD diagnosis, and markers of severity. METHODS: A multi-center cross-sectional study was conducted. A total 224 functional dyspepsia (FD) patients cohort who underwent gastroscopy was selected. Biochemical, clinical parameters, ultrasound, FIB-4 score, LSM by VCTE, gastric biopsies, H. pylori status, and rs738409 PNPLA3 were evaluated. A second retrospective cohort of 86 patients with biopsy-proven MASLD who underwent gastroscopy with gastric biopsies was analyzed. RESULTS: In the FD cohort MASLD was observed in 52%, and H. pylori-positive in 51%. H. pylori infection was associated with MASLD prevalence, but in multivariate analyses adjusted for G-allele PNPLA3, it became not significant. Then in MASLD-only dyspeptic cohort, H. pylori infection was significantly linked to elevated serum AST levels and increased liver stiffness measurements, suggesting a potential role in liver injury and fibrosis. Histopathological analysis in biopsy-proven MASLD patients further supported these findings, showing a significant association between H. pylori infection and increased NAS score, fibrosis stage, and prevalence of MASH. Notably, the combination of H. pylori infection and G-allele PNPLA3 appeared to exacerbate MASLD severity beyond individual effects. CONCLUSIONS: Our results suggest that H. pylori infection may play a role in the progression of liver injury and fibrosis in patients with MASLD, especially in those with specific genetic predispositions.
Assuntos
Infecções por Helicobacter , Helicobacter pylori , Lipase , Proteínas de Membrana , Humanos , Masculino , Feminino , Lipase/genética , Proteínas de Membrana/genética , Pessoa de Meia-Idade , Infecções por Helicobacter/complicações , Infecções por Helicobacter/genética , Adulto , Estudos Transversais , Estudos Retrospectivos , Fígado Gorduroso/genética , Fígado Gorduroso/complicações , Alelos , Polimorfismo de Nucleotídeo Único , Dispepsia/microbiologia , Dispepsia/genética , Dispepsia/complicações , Fígado/patologia , Fígado/metabolismo , Aciltransferases , Fosfolipases A2 Independentes de CálcioRESUMO
Objective: Metabolic dysfunction-associated steatohepatitis (MASH) is characterized by inflammation, fibrosis, and accumulation of fatty acids in the liver. MASH disease progression has been associated with reduced thyroid hormone (TH) signaling in the liver, including reduced expression of deiodinase type I (DIO1) and TH receptor beta (THRB). However, the underlying mechanisms mediating these effects remain elusive. Here, we hypothesized that epigenetic mechanisms may be involved in modulating hepatic TH action. Methods: Liver samples from patients with and without MASH were analyzed by qRT-PCR and correlated with clinical parameters. Luciferase reporter assays and overexpression of miRNA in HepG2 cells were used to validate the functional binding of miRNA to predicted targets. DNA methylation was analyzed by bisulfite pyrosequencing. Results: miR-34a-5p was upregulated in MASH patients and correlated positively with the clinical parameters of MASH. Using in silico and in vitro analysis, we demonstrate that miR-34a-5p is capable of targeting several modulators of local hepatic TH action, as evidenced by the functional binding of miR-34a-5p to the seed sequence in the THRB and DIO1 genes. Consequently, overexpression of miR-34a-5p in HepG2 cells reduced the expression of THRA, THRB, DIO1, and SLC10A1, thus potentially mediating an acquired hepatic resistance to TH in MASH. As an additional regulatory mechanism, DNA methylation of THRB intron 1 was increased in MASH and negatively correlated with THRB expression. Conclusion: miR-34a-5p constitutes a possible epigenetic master regulator of hepatic TH action, which together with THRB-specific DNA methylation could explain a possible developing TH resistance in the liver during MASH progression on the molecular level.
Assuntos
Metilação de DNA , Epigênese Genética , Iodeto Peroxidase , MicroRNAs , Receptores beta dos Hormônios Tireóideos , Hormônios Tireóideos , Humanos , Células Hep G2 , MicroRNAs/genética , MicroRNAs/metabolismo , Masculino , Feminino , Hormônios Tireóideos/metabolismo , Hormônios Tireóideos/genética , Receptores beta dos Hormônios Tireóideos/genética , Receptores beta dos Hormônios Tireóideos/metabolismo , Pessoa de Meia-Idade , Iodeto Peroxidase/genética , Iodeto Peroxidase/metabolismo , Fígado/metabolismo , Fígado/patologia , Fígado Gorduroso/genética , Fígado Gorduroso/metabolismo , Fígado Gorduroso/patologia , AdultoRESUMO
Succinate is an important metabolite and a critical chemical with diverse applications in the food, pharmaceutical, and agriculture industries. Recent studies have demonstrated several protective or detrimental functions of succinate in diseases; however, the effect of succinate on lipid metabolism is still unclear. Here, we identified a role of succinate in nonobese nonalcoholic fatty liver disease (NAFLD). Specifically, the level of succinate is increased in the livers and serum of mice with hepatic steatosis. The administration of succinate promotes triglyceride (TG) deposition and hepatic steatosis by suppressing fatty acid oxidation (FAO) in nonobese NAFLD mouse models. RNA-Seq revealed that succinate suppressed fibroblast growth factor 21 (FGF21) expression. Then, the restoration of FGF21 was sufficient to alleviate hepatic steatosis and FAO inhibition induced by succinate treatment in vitro and in vivo. Furthermore, the inhibition of FGF21 expression and FAO mediated by succinate was dependent on the AMPK/PPARα axis. This study provides evidence linking succinate exposure to abnormal hepatic lipid metabolism and the progression of nonobese NAFLD.
Assuntos
Proteínas Quinases Ativadas por AMP , Ácidos Graxos , Fatores de Crescimento de Fibroblastos , Fígado , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica , Oxirredução , PPAR alfa , Ácido Succínico , Fatores de Crescimento de Fibroblastos/genética , Fatores de Crescimento de Fibroblastos/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismo , Hepatopatia Gordurosa não Alcoólica/genética , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Animais , PPAR alfa/metabolismo , PPAR alfa/genética , Camundongos , Masculino , Ácidos Graxos/metabolismo , Proteínas Quinases Ativadas por AMP/metabolismo , Proteínas Quinases Ativadas por AMP/genética , Humanos , Ácido Succínico/metabolismo , Fígado/metabolismo , Fígado/efeitos dos fármacos , Metabolismo dos Lipídeos/efeitos dos fármacos , Fígado Gorduroso/metabolismo , Fígado Gorduroso/genéticaRESUMO
Metabolic dysfunction-associated steatotic liver disease (MASLD) is a prevalent chronic liver condition worldwide, demanding further investigation into its pathogenesis. Circular RNAs (circRNAs) are emerging as pivotal regulators in MASLD processes, yet their pathological implications in MASLD remain poorly understood. This study focused on elucidating the role of circular RNA ribonucleotide reductase subunit M2 (circRRM2) in MASLD progression. In this study, we used both in vitro and in vivo MASLD models using long-chain-free fatty acid (FFA)-treated hepatocytes and high-fat diet (HFD)-induced MASLD in mice, respectively. We determined the expression patterns of circRRM2, microRNA-142-5p (miR-142-5p), and neuregulin 1 (NRG1) in livers of MASLD-afflicted mice and MASLD hepatocytes by RT-qPCR. Dual-luciferase reporter assays verified the binding relationships among circRRM2, miR-142-5p, and NRG1. We conducted further analyses of their roles in MASLD hepatocytes and modulated circRRM2, miR-142-5p, and NRG1 expression in vitro by transfection. Our findings were validated in vivo. The results demonstrated reduced levels of circRRM2 and NRG1, along with elevated miR-142-5p expression in MASLD livers and hepatocytes. Overexpression of circRRM2 downregulated lipogenesis-related genes and decreased triglycerides accumulation in livers of MASLD mice. MiR-142-5p, which interacts with circRRM2, effectively counteracted the effects of circRRM2 in MASLD hepatocytes. Furthermore, NRG1 was identified as a miR-142-5p target, and its overexpression mitigated the regulatory impact of miR-142-5p on MASLD hepatocytes. In conclusion, circRRM2, via its role as a miR-142-5p sponge, upregulating NRG1, possibly influenced triglycerides accumulation in both in vitro and in vivo MASLD models.NEW & NOTEWORTHY CircRRM2 expression was downregulated in free fatty acid (FFA)-challenged hepatocytes and high-fat diet (HFD) fed mice. Overexpressed circular RNA ribonucleotide reductase subunit M2 (circRRM2) attenuated metabolic dysfunction-associated steatotic liver disease (MASLD) development by suppressing FFA-induced triglycerides accumulation. CircRRM2 targeted microRNA-142-5p (miR-142-5p), which served as an upstream inhibitor of neuregulin 1 (NRG1) and collaboratively regulated MASLD progression.
Assuntos
Dieta Hiperlipídica , Hepatócitos , MicroRNAs , Neuregulina-1 , RNA Circular , Animais , MicroRNAs/metabolismo , MicroRNAs/genética , Camundongos , Hepatócitos/metabolismo , RNA Circular/genética , RNA Circular/metabolismo , Masculino , Neuregulina-1/genética , Neuregulina-1/metabolismo , Camundongos Endogâmicos C57BL , Fígado Gorduroso/metabolismo , Fígado Gorduroso/genética , Humanos , Fígado/metabolismo , Fígado/patologia , Hepatopatia Gordurosa não Alcoólica/metabolismo , Hepatopatia Gordurosa não Alcoólica/genética , Ribonucleosídeo Difosfato RedutaseRESUMO
Many factors are associated with the development and progression of metabolic dysfunction-associated steatotic liver disease (MASLD); however, genetics and gut microbiota are representative factors. Recent studies have highlighted the link between host genes and the gut microbiota. Although there have been many studies on the separate effects of single nucleotide polymorphisms (SNPs) and gut bacteria on MASLD, few epidemiological studies have examined how SNPs and gut bacteria interact in the development and progression of MASLD. This study aimed to investigate the association between PNPLA3 rs738409, a representative MASLD-related SNP, and gut bacteria in MASLD using a cross-sectional study of the general population. The 526 participants (318 normal and 208 MASLD groups) were grouped into the PNPLA3 rs738409 SNP, CC, CG, and GG genotypes, and the differences in the gut microbiota were investigated in each group. The PNPLA3 rs738409 CC and CG genotypes were associated with decreased Blautia and Ruminococcaceae in the MASLD group. They were negatively correlated with controlled attenuation parameter levels, body mass index, serum blood glucose, and triglycerides. In contrast, there was no association between the normal and MASLD groups and the gut bacteria in the PNPLA3 rs738409, the GG genotype group. This finding implies that dietary interventions and probiotics may be more effective in preventing and treating MASLD in individuals with the PNPLA3 rs738409 CC and CG genotypes. In contrast, their efficacy may be limited in those with the GG genotype.
Assuntos
Microbioma Gastrointestinal , Lipase , Proteínas de Membrana , Polimorfismo de Nucleotídeo Único , Humanos , Microbioma Gastrointestinal/genética , Proteínas de Membrana/genética , Masculino , Feminino , Pessoa de Meia-Idade , Lipase/genética , Estudos Transversais , Adulto , Idoso , Fígado Gorduroso/genética , Fígado Gorduroso/microbiologia , Fígado Gorduroso/patologia , Genótipo , Aciltransferases , Fosfolipases A2 Independentes de CálcioRESUMO
RNA splicing is an essential post-transcriptional mechanism that facilitates the excision of introns and the connection of exons to produce mature mRNA, which is essential for gene expression and proteomic diversity. In the liver, precise splicing regulation is critical for maintaining metabolic balance, detoxification, and protein synthesis. This review explores the mechanisms of RNA splicing and the role of splicing factors, particularly in the context of Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD). This review also highlights how RNA splicing dysregulation can lead to aberrant splicing and impact the progression of liver diseases such as MASLD, with a particular focus on Metabolic Dysfunction-Associated Steatohepatitis (MASH), which represents the advanced stage of MASLD. Recent advances in the clinical application of antisense oligonucleotides (ASOs) to correct splicing errors offer promising therapeutic strategies for restoring normal liver function. Additionally, the dysregulation of splicing observed in liver diseases may serve as a potential diagnostic marker, offering new opportunities for early identification of individuals more susceptible to disease progression. This review provides insights into the molecular mechanisms that govern splicing regulation in the liver, with a particular emphasis on MASLD, and discusses potential therapeutic approaches targeting RNA splicing to treat MASLD and related metabolic disorders.
Assuntos
Fígado , Splicing de RNA , Humanos , Splicing de RNA/genética , Fígado/metabolismo , Fígado/patologia , Fígado Gorduroso/genética , Fígado Gorduroso/metabolismo , Fígado Gorduroso/patologia , Animais , Oligonucleotídeos Antissenso/genética , Oligonucleotídeos Antissenso/uso terapêuticoRESUMO
The endocannabinoid system (ECS) plays a crucial role in reproductive health, but its function in postpartum dairy cows remains poorly understood. This study investigated the expression patterns of ECS-related genes in the endometrium of postpartum dairy cows and their associations with endometrial health and the presence of fatty liver. Endometrial biopsies were collected from 22 Holstein Friesian cows at 4 and 7 weeks postpartum. Gene expression was analyzed using RT-qPCR, focusing on key ECS components including CNR2, MGLL, FAAH1, NAAA, NAPEPLD, PADI4 and PTGDS. The results reveal dynamic changes in ECS gene expression associated with endometritis and fatty liver. MGLL expression was significantly upregulated in cows with endometritis at 7 weeks postpartum, while NAAA expression was consistently downregulated in cows with fatty liver. CNR2 showed a time-dependent pattern in endometritis, and PTGDS expression was elevated in clinical endometritis at 4 weeks postpartum. The presence of fatty liver was associated with altered expression patterns of several ECS genes, suggesting a link between metabolic stress and endometrial ECS function. These findings indicate a potential role for the ECS in postpartum uterine health and recovery, offering new insights into the molecular mechanisms underlying reproductive disorders in dairy cows and paving the way for novel therapeutic approaches.
Assuntos
Doenças dos Bovinos , Endocanabinoides , Endométrio , Fígado Gorduroso , Período Pós-Parto , Animais , Feminino , Bovinos , Endométrio/metabolismo , Endométrio/patologia , Endocanabinoides/metabolismo , Endocanabinoides/genética , Fígado Gorduroso/genética , Fígado Gorduroso/veterinária , Fígado Gorduroso/metabolismo , Período Pós-Parto/genética , Período Pós-Parto/metabolismo , Doenças dos Bovinos/genética , Doenças dos Bovinos/metabolismo , Endometrite/veterinária , Endometrite/genética , Endometrite/metabolismo , Regulação da Expressão GênicaRESUMO
The onset and progression mechanisms of metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH) are being studied. We developed and analyzed a new mouse model of obesity by combining maternal Id-like molecule (Maid) and melanocortin-4 receptor (Mc4r) gene deletions. Four mice, each at 12 and 28 weeks of age, were analyzed for each genotype: Maid gene knockout, Mc4r gene knockout, combined Mc4r and Maid gene knockout, and Mc4r gene knockout with a high-fat diet. Mice with a combined deficiency of Mc4r and Maid gene showed significantly more severe obesity compared to all other genotypes, but no liver fibrosis or a decline in metabolic status were observed. In visceral white adipose tissue, Maid and Mc4r gene knockout mice had fewer CD11c-positive cells and lower mRNA expression of both inflammatory and anti-inflammatory cytokines. Furthermore, Maid and Mc4r gene knockout mice showed lower expression of adipocytokines in visceral white adipose tissue and uncoupling protein-1 in scapular brown adipose tissue. The expression of adipocytokines and uncoupling protein-1 is regulated by sympathetic nerve signaling that contribute severe obesity in Maid and Mc4r gene knockout mice. These mechanisms contribute hyperobesity in Maid and Mc4r gene knockout mice.
Assuntos
Inflamação , Obesidade , Receptor Tipo 4 de Melanocortina , Animais , Masculino , Camundongos , Adipocinas/metabolismo , Adipocinas/genética , Tecido Adiposo/metabolismo , Tecido Adiposo/patologia , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Marrom/patologia , Tecido Adiposo Branco/metabolismo , Tecido Adiposo Branco/patologia , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Fígado Gorduroso/genética , Fígado Gorduroso/patologia , Fígado Gorduroso/metabolismo , Inflamação/genética , Inflamação/metabolismo , Inflamação/patologia , Camundongos Knockout , Obesidade/genética , Obesidade/metabolismo , Receptor Tipo 4 de Melanocortina/genética , Receptor Tipo 4 de Melanocortina/deficiência , Receptor Tipo 4 de Melanocortina/metabolismo , Proteína Desacopladora 1/genética , Proteína Desacopladora 1/metabolismoRESUMO
Recently, we have demonstrated that mice, cultured embryos in α-minimum essential medium (αMEM) and subsequent fed a high-fat, high-sugar diet, developed steatohepatitis. In this study, we investigated using these samples whether the expression of lipid droplet formation genes in the liver is higher in MEM mice, whether these expressions are regulated by histone acetylation, writers/readers of histone acetylation, and the transcriptional factors of endoplasmic reticulum stress. Mice were produced by two-cell embryos in αMEM or standard potassium simplex-optimized medium (control) in vitro for 48 h, and implanted into an oviduct for spontaneous delivery. MEM and control-mice were fed a high-fat, high-sugar diet for 18 wk, and then liver samples were collected and analyzed by histology, qRT-PCR, and chromatin immunoprecipitation assay. Gene expression of Cidea, Cidec, and Plin4 were higher in MEM mice and histone H3K9 acetylation, BRD4, and CBP were higher in MEM mice than in control mice around those genes. However, the binding of endoplasmic reticulum stress-related transcription factors (ATF4, CHOP and C/EBPα) around those genes in the liver, was not clearly differed between MEM mice and control mice. The increased expression of Cidea, Cidec and Plin4 in the liver, accompanied by the development of steatohepatitis in mice induced is positively associated with increased histone H3K9 acetylation and CBP and BRD4 binding around these genes.
Assuntos
Estresse do Retículo Endoplasmático , Fígado Gorduroso , Histonas , Gotículas Lipídicas , Fígado , Animais , Histonas/metabolismo , Acetilação , Gotículas Lipídicas/metabolismo , Camundongos , Feminino , Fígado/metabolismo , Fígado Gorduroso/metabolismo , Fígado Gorduroso/genética , Fígado Gorduroso/etiologia , Fator 4 Ativador da Transcrição/metabolismo , Fator 4 Ativador da Transcrição/genética , Dieta Hiperlipídica/efeitos adversos , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Fator de Transcrição CHOP/metabolismo , Fator de Transcrição CHOP/genética , Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Proteínas Estimuladoras de Ligação a CCAAT/genética , Proteínas Reguladoras de Apoptose/metabolismo , Proteínas Reguladoras de Apoptose/genéticaRESUMO
Metabolic dysfunction-associated diseases often refer to various diseases caused by metabolic problems such as glucose and lipid metabolism disorders. With the improvement of living standards, the increasing prevalence of metabolic diseases has become a severe public health problem, including metabolic dysfunction-associated steatotic liver disease (MASLD), alcohol-related liver disease (ALD), diabetes and obesity. These diseases are both independent and interdependent, with complex and diverse molecular mechanisms. Therefore, it is urgent to explore the molecular mechanisms and find effective therapeutic targets of these diseases. MicroRNAs (miRNAs) have emerged as key regulators of metabolic homoeostasis due to their multitargets and network regulatory properties within the past few decades. In this review, we discussed the latest progress in the roles of miRNA-mediated regulatory networks in the development and progression of MASLD, ALD, diabetes and obesity.
Assuntos
Doenças Metabólicas , MicroRNAs , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Animais , Doenças Metabólicas/metabolismo , Doenças Metabólicas/terapia , Doenças Metabólicas/genética , Obesidade/metabolismo , Obesidade/genética , Diabetes Mellitus/metabolismo , Diabetes Mellitus/genética , Diabetes Mellitus/terapia , Fígado Gorduroso/metabolismo , Fígado Gorduroso/genética , Fígado Gorduroso/terapia , Fígado Gorduroso/etiologiaRESUMO
The function of hydroxysteroid dehydrogenase 12 (HSD17B12) in lipid metabolism is poorly understood. To study this further, we created mice with hepatocyte-specific knockout of HSD17B12 (LiB12cKO). From 2 months on, these mice showed significant fat accumulation in their liver. As they aged, they also had a reduced whole-body fat percentage. Interestingly, the liver fat accumulation did not result in the typical formation of large lipid droplets (LD); instead, small droplets were more prevalent. Thus, LiB12KO liver did not show increased macrovesicular steatosis with the increasing fat content, while microvesicular steatosis was the predominant feature in the liver. This indicates a failure in the LD expansion. This was associated with liver damage, presumably due to lipotoxicity. Notably, the lipidomics data did not support an essential role of HSD17B12 in fatty acid (FA) elongation. However, we did observe a decrease in the quantity of specific lipid species that contain FAs with carbon chain lengths of 18 and 20 atoms, including oleic acid. Of these, phosphatidylcholine and phosphatidylethanolamine have been shown to play a key role in LD formation, and a limited amount of these lipids could be part of the mechanism leading to the dysfunction in LD expansion. The increase in the Cidec expression further supported the deficiency in LD expansion in the LiB12cKO liver. This protein is crucial for the fusion and growth of LDs, along with the downregulation of several members of the major urinary protein family of proteins, which have recently been shown to be altered during endoplasmic reticulum stress.
Assuntos
Fígado Gorduroso , Hepatócitos , Gotículas Lipídicas , Camundongos Knockout , Animais , Camundongos , Gotículas Lipídicas/metabolismo , Hepatócitos/metabolismo , Fígado Gorduroso/metabolismo , Fígado Gorduroso/patologia , Fígado Gorduroso/genética , 17-Hidroxiesteroide Desidrogenases/metabolismo , 17-Hidroxiesteroide Desidrogenases/genética , Metabolismo dos Lipídeos , Peso Corporal , Fígado/metabolismo , Fígado/patologia , Masculino , Camundongos Endogâmicos C57BL , Ácidos Graxos/metabolismoRESUMO
Endoplasmic reticulum (ER) stress is a major cause of hepatic steatosis through increasing de novo lipogenesis. Forkhead box O6 (FoxO6) is a transcription factor mediating insulin signaling to glucose and lipid metabolism. Therefore, dysregulated FoxO6 is involved in hepatic lipogenesis. This study elucidated the role of FoxO6 in ER stress-induced hepatic steatosis in vivo and in vitro. Hepatic ER stress responses and ß-oxidation were monitored in mice overexpressed with constitutively active FoxO6 allele and FoxO6-null mice. For the in vitro study, liver cells overexpressing constitutively active FoxO6 and FoxO6-siRNA were treated with high glucose, and lipid metabolism alterations were measured. ER stress-induced FoxO6 activation suppressed hepatic ß-oxidation in vivo. The expression and transcriptional activity of peroxisome proliferator-activated receptor α (PPARα) were significantly decreased in the constitutively active FoxO6 allele. Otherwise, inhibiting ß-oxidation genes were reduced in the FoxO6-siRNA and FoxO6-KO mice. Our data showed that the FoxO6-induced hepatic lipid accumulation was negatively regulated by insulin signaling. High glucose treatment as a hyperglycemia condition caused the expression of ER stress-inducible genes, which was deteriorated by FoxO6 activation in liver cells. However, high glucose-mediated ER stress suppressed ß-oxidation gene expression through interactions between PPARα and FoxO6 corresponding to findings in the in vivo study-lipid catabolism is also regulated by FoxO6. Furthermore, insulin resistance suppressed b-oxidation through the interaction between FoxO6 and PPARα promotes hepatic steatosis, which, due to hyperglycemia-induced ER stress, impairs insulin signaling. KEY MESSAGES: Our original aims were to delineate the interrelation between the regulation of PPARα and the transcription factor FoxO6 pathway in relation to lipid metabolism at molecular levels. Evidence on high glucose promoted FoxO6 activation induced lipid accumulation in liver cells. The effect of PPARα activation of the insulin signaling. FoxO6 plays a pivotal role in hepatic lipid accumulation through inactivation of PPARα in FoxO6-overexpression mice.
Assuntos
Estresse do Retículo Endoplasmático , Fatores de Transcrição Forkhead , PPAR alfa , Animais , PPAR alfa/metabolismo , PPAR alfa/genética , Fatores de Transcrição Forkhead/metabolismo , Fatores de Transcrição Forkhead/genética , Camundongos , Metabolismo dos Lipídeos , Fígado Gorduroso/metabolismo , Fígado Gorduroso/genética , Fígado Gorduroso/patologia , Camundongos Knockout , Masculino , Fígado/metabolismo , Transdução de Sinais , Camundongos Endogâmicos C57BL , Glucose/metabolismo , Insulina/metabolismo , HumanosRESUMO
The burden of senescent hepatocytes correlates with the severity of metabolic dysfunction-associated steatotic liver disease (MASLD), but the mechanisms driving senescence and how it exacerbates MASLD are poorly understood. Hepatocytes experience lipotoxicity and become senescent when Smoothened (Smo) is deleted to disrupt Hedgehog signaling. We aimed to determine whether the secretomes of Smo-deficient hepatocytes perpetuate senescence to drive MASLD progression. RNA-Seq analysis of liver samples from human and murine cohorts with MASLD confirmed that hepatocyte populations in MASLD livers were depleted of Smo+ cells and enriched with senescent cells. When fed a choline-deficient, amino acid-restricted high-fat diet (CDA-HFD) to induce MASLD, Smo- mice had lower antioxidant markers and developed worse DNA damage, senescence, steatohepatitis, and fibrosis than did Smo+ mice. Sera and hepatocyte-conditioned medium from Smo- mice were depleted of thymidine phosphorylase (TP), a protein that maintains mitochondrial fitness. Treating Smo- hepatocytes with TP reduced senescence and lipotoxicity, whereas inhibiting TP in Smo+ hepatocytes had the opposite effect and exacerbated hepatocyte senescence, steatohepatitis, and fibrosis in CDA-HFD-fed mice. We conclude that inhibition of Hedgehog signaling in hepatocytes promoted MASLD by suppressing hepatocyte production of proteins that prevent lipotoxicity and senescence.
Assuntos
Senescência Celular , Proteínas Hedgehog , Hepatócitos , Receptor Smoothened , Animais , Hepatócitos/metabolismo , Hepatócitos/patologia , Camundongos , Proteínas Hedgehog/metabolismo , Proteínas Hedgehog/genética , Receptor Smoothened/metabolismo , Receptor Smoothened/genética , Humanos , Masculino , Fígado Gorduroso/metabolismo , Fígado Gorduroso/patologia , Fígado Gorduroso/genética , Transdução de Sinais , Camundongos Knockout , Progressão da DoençaRESUMO
Progression of metabolic dysfunction-associated steatites liver disease (MASLD) to steatohepatitis (MASH) is driven by stress-inducing lipids that promote liver inflammation and fibrosis, and MASH can lead to cirrhosis and hepatocellular carcinoma. Previously, we showed coordinated defenses regulated by transcription factors, nuclear factor erythroid 2-related factor-1 (Nrf1) and -2 (Nrf2), protect against hepatic lipid stress. Here, we investigated protective effects of hepatocyte Nrf1 and Nrf2 against MASH-linked liver fibrosis and tumorigenesis. Male and female mice with flox alleles for genes encoding Nrf1 (Nfe2l1), Nrf2 (Nfe2l2), or both were fed a MASH-inducing diet enriched with high fat, fructose, and cholesterol (HFFC) or a control diet for 24-52 weeks. During this period, hepatocyte Nrf1, Nrf2, or combined deficiency for ~7 days, ~7 weeks, and ~35 weeks was induced by administering mice hepatocyte-targeting adeno-associated virus (AAV) expressing Cre recombinase. The effects on MASH, markers of liver fibrosis and proliferation, and liver tumorigenesis were compared to control mice receiving AAV-expressing green fluorescent protein. Also, to assess the impact of Nrf1 and Nrf2 induction on liver fibrosis, HFFC diet-fed C57bl/6J mice received weekly injections of carbon tetrachloride, and from week 16 to 24, mice were treated with the Nrf2-activating drug bardoxolone, hepatocyte overexpression of human NRF1 (hNRF1), or both, and these groups were compared to control. Compared to the control diet, 24-week feeding with the HFFC diet increased bodyweight as well as liver weight, steatosis, and inflammation. It also increased hepatocyte proliferation and a marker of liver damage, p62. Hepatocyte Nrf1 and combined deficiency increased liver steatosis in control diet-fed but not HFFC diet-fed mice, and increased liver inflammation under both diet conditions. Hepatocyte Nrf1 deficiency also increased hepatocyte proliferation, whereas combined deficiency did not, and this also occurred for p62 level in control diet-fed conditions. In 52-week HFFC diet-fed mice, 35 weeks of hepatocyte Nrf1 deficiency, but not combined deficiency, resulted in more liver tumors in male mice, but not in female mice. In contrast, hepatocyte Nrf2 deficiency had no effect on any of these parameters. However, in the 15-week CCL4-exposed and 24-week HFFC diet-fed mice, Nrf2 induction with bardoxolone reduced liver steatosis, inflammation, fibrosis, and proliferation. Induction of hepatic Nrf1 activity with hNRF1 enhanced the effect of bardoxolone on steatosis and may have stimulated liver progenitor cells. Physiologic Nrf1 delays MASLD progression, Nrf2 induction alleviates MASH, and combined enhancement synergistically protects against steatosis and may facilitate liver repair.
Assuntos
Hepatócitos , Fator 2 Relacionado a NF-E2 , Animais , Fator 2 Relacionado a NF-E2/metabolismo , Fator 2 Relacionado a NF-E2/genética , Camundongos , Hepatócitos/metabolismo , Masculino , Feminino , Progressão da Doença , Camundongos Endogâmicos C57BL , Fígado Gorduroso/metabolismo , Fígado Gorduroso/patologia , Fígado Gorduroso/genética , Cirrose Hepática/metabolismo , Cirrose Hepática/patologia , Cirrose Hepática/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Fator 1 Relacionado a NF-E2/metabolismo , Fator 1 Relacionado a NF-E2/genética , Fator 1 Nuclear Respiratório/metabolismo , Fator 1 Nuclear Respiratório/genética , Dieta Hiperlipídica/efeitos adversos , Fígado/metabolismo , Fígado/patologia , HumanosRESUMO
Eukaryotic elongation factor 1A1 (EEF1A1), originally identified for its role in protein synthesis, has additional functions in diverse cellular processes. Of note, we previously discovered a role for EEF1A1 in hepatocyte lipotoxicity. We also demonstrated that a 2-wk intervention with the EEF1A1 inhibitor didemnin B (DB) (50 µg/kg) decreased liver steatosis in a mouse model of obesity and metabolic dysfunction-associated steatotic liver disease (MASLD) [129S6/SvEvTac mice fed Western diet (42% fat) for 26 wk]. Here, we further characterized the hepatic changes occurring in these mice by assessing lipid droplet (LD) size, bulk differential expression, and cell type-associated alterations in gene expression. Consistent with the previously demonstrated decrease in hepatic steatosis, we observed decreased median LD size in response to DB. Bulk RNA sequencing (RNA-Seq) followed by gene set enrichment analysis revealed alterations in pathways related to energy metabolism and proteostasis in DB-treated mouse livers. Deconvolution of bulk data identified decreased cell type association scores for cholangiocytes, mononuclear phagocytes, and mesenchymal cells in response to DB. Overrepresentation analyses of bulk data using cell type marker gene sets further identified hepatocytes and cholangiocytes as the primary contributors to bulk differential expression in response to DB. Thus, we show that chemical inhibition of EEF1A1 decreases hepatic LD size and decreases gene expression signatures associated with several liver cell types implicated in MASLD progression. Furthermore, changes in hepatic gene expression were primarily attributable to hepatocytes and cholangiocytes. This work demonstrates that EEF1A1 inhibition may be a viable strategy to target aspects of liver biology implicated in MASLD progression.NEW & NOTEWORTHY Chemical inhibition of EEF1A1 decreases hepatic lipid droplet size and decreases gene expression signatures associated with liver cell types that contribute to MASLD progression. Furthermore, changes in hepatic gene expression are primarily attributable to hepatocytes and cholangiocytes. This work highlights the therapeutic potential of targeting EEF1A1 in the setting of MASLD, and the utility of RNA-Seq deconvolution to reveal valuable information about tissue cell type composition and cell type-associated gene expression from bulk RNA-Seq data.
Assuntos
Gotículas Lipídicas , Fígado , Fator 1 de Elongação de Peptídeos , Transcriptoma , Animais , Fator 1 de Elongação de Peptídeos/metabolismo , Fator 1 de Elongação de Peptídeos/genética , Gotículas Lipídicas/metabolismo , Gotículas Lipídicas/efeitos dos fármacos , Camundongos , Fígado/metabolismo , Fígado/efeitos dos fármacos , Masculino , Fígado Gorduroso/metabolismo , Fígado Gorduroso/genética , Fígado Gorduroso/patologia , Hepatócitos/metabolismo , Hepatócitos/efeitos dos fármacos , Modelos Animais de Doenças , Hepatopatia Gordurosa não Alcoólica/metabolismo , Hepatopatia Gordurosa não Alcoólica/genéticaRESUMO
BACKGROUND: Existing studies have presented limited and disparate findings on the nexus between immune cells, plasma metabolites, and metabolic dysfunction-associated steatotic liver disease (MASLD). The aim of this study was to investigate the causal relationship between immune cells and MASLD. Additionally, we aimed to identify and quantify the potential mediating role of metabolites. METHODS: A Mendelian randomization (MR) analysis was conducted using two samples of pooled data from genome-wide association studies on MASLD that included 2568 patients and 409,613 control individuals. Additionally, a mediated MR study was employed to quantify the metabolite-mediated immune cell effects on MASLD. RESULTS: In this study, eight immunophenotypes were linked to the risk of MASLD, and thirty-five metabolites/metabolite ratios were linked to the occurrence of MASLD. Furthermore, a total of six combinations of immunophenotypic and metabolic factors demonstrated effects on the occurrence of MASLD, although the mediating effects of metabolites were not significant. CONCLUSION: Our study demonstrated that certain immunophenotypes and metabolite/metabolite ratios have independent causal relationships with MASLD. Furthermore, we identified specific metabolites/metabolite ratios that are associated with an increased risk of MASLD. However, their mediating role in the causal association between immunophenotypes and MASLD was not significant. It is important to consider immune and metabolic disorders among patients with MASLD in clinical practice.
Assuntos
Estudo de Associação Genômica Ampla , Análise da Randomização Mendeliana , Humanos , Polimorfismo de Nucleotídeo Único , Fígado Gorduroso/genética , Fígado Gorduroso/metabolismo , Fígado Gorduroso/patologia , Fígado Gorduroso/imunologia , Imunofenotipagem , MasculinoRESUMO
Genetic susceptibility to metabolic associated fatty liver disease (MAFLD) is complex and poorly characterized. Accurate characterization of the genetic background of hepatic fat content would provide insights into disease etiology and causality of risk factors. We performed genome-wide association study (GWAS) on two noninvasive definitions of hepatic fat content: magnetic resonance imaging proton density fat fraction (MRI-PDFF) in 16,050 participants and fatty liver index (FLI) in 388,701 participants from the United Kingdom (UK) Biobank (UKBB). Heritability, genetic overlap, and similarity between hepatic fat content phenotypes were analyzed, and replicated in 10,398 participants from the University Medical Center Groningen (UMCG) Genetics Lifelines Initiative (UGLI). Meta-analysis of GWASs of MRI-PDFF in UKBB revealed five statistically significant loci, including two novel genomic loci harboring CREB3L1 (rs72910057-T, P = 5.40E-09) and GCM1 (rs1491489378-T, P = 3.16E-09), respectively, as well as three previously reported loci: PNPLA3, TM6SF2, and APOE. GWAS of FLI in UKBB identified 196 genome-wide significant loci, of which 49 were replicated in UGLI, with top signals in ZPR1 (P = 3.35E-13) and FTO (P = 2.11E-09). Statistically significant genetic correlation (rg) between MRI-PDFF (UKBB) and FLI (UGLI) GWAS results was found (rg = 0.5276, P = 1.45E-03). Novel MRI-PDFF genetic signals (CREB3L1 and GCM1) were replicated in the FLI GWAS. We identified two novel genes for MRI-PDFF and 49 replicable loci for FLI. Despite a difference in hepatic fat content assessment between MRI-PDFF and FLI, a substantial similar genetic architecture was found. FLI is identified as an easy and reliable approach to study hepatic fat content at the population level.