Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 31
Filter
Add more filters











Publication year range
1.
Front Cell Dev Biol ; 12: 1433857, 2024.
Article in English | MEDLINE | ID: mdl-39086662

ABSTRACT

Metabolic dysfunction-associated steatotic liver disease (MASLD), previously known as non-alcoholic fatty liver disease (NAFLD), is the most common liver disorder worldwide, with an estimated global prevalence of more than 31%. Metabolic dysfunction-associated steatohepatitis (MASH), formerly known as non-alcoholic steatohepatitis (NASH), is a progressive form of MASLD characterized by hepatic steatosis, inflammation, and fibrosis. This review aims to provide a comprehensive analysis of the extrahepatic manifestations of MASH, focusing on chronic diseases related to the cardiovascular, muscular, and renal systems. A systematic review of published studies and literature was conducted to summarize the findings related to the systemic impacts of MASLD and MASH. The review focused on the association of MASLD and MASH with metabolic comorbidities, cardiovascular mortality, sarcopenia, and chronic kidney disease. Mechanistic insights into the concept of lipotoxic inflammatory "spill over" from the MASH-affected liver were also explored. MASLD and MASH are highly associated (50%-80%) with other metabolic comorbidities such as impaired insulin response, type 2 diabetes, dyslipidemia, hypertriglyceridemia, and hypertension. Furthermore, more than 90% of obese patients with type 2 diabetes have MASH. Data suggest that in middle-aged individuals (especially those aged 45-54), MASLD is an independent risk factor for cardiovascular mortality, sarcopenia, and chronic kidney disease. The concept of lipotoxic inflammatory "spill over" from the MASH-affected liver plays a crucial role in mediating the systemic pathological effects observed. Understanding the multifaceted impact of MASH on the heart, muscle, and kidney is crucial for early detection and risk stratification. This knowledge is also timely for implementing comprehensive disease management strategies addressing multi-organ involvement in MASH pathogenesis.

2.
Nature ; 632(8023): 157-165, 2024 Aug.
Article in English | MEDLINE | ID: mdl-39020175

ABSTRACT

For healthspan and lifespan, ERK, AMPK and mTORC1 represent critical pathways and inflammation is a centrally important hallmark1-7. Here we examined whether IL-11, a pro-inflammatory cytokine of the IL-6 family, has a negative effect on age-associated disease and lifespan. As mice age, IL-11 is upregulated across cell types and tissues to regulate an ERK-AMPK-mTORC1 axis to modulate cellular, tissue- and organismal-level ageing pathologies. Deletion of Il11 or Il11ra1 protects against metabolic decline, multi-morbidity and frailty in old age. Administration of anti-IL-11 to 75-week-old mice for 25 weeks improves metabolism and muscle function, and reduces ageing biomarkers and frailty across sexes. In lifespan studies, genetic deletion of Il11 extended the lives of mice of both sexes, by 24.9% on average. Treatment with anti-IL-11 from 75 weeks of age until death extends the median lifespan of male mice by 22.5% and of female mice by 25%. Together, these results demonstrate a role for the pro-inflammatory factor IL-11 in mammalian healthspan and lifespan. We suggest that anti-IL-11 therapy, which is currently in early-stage clinical trials for fibrotic lung disease, may provide a translational opportunity to determine the effects of IL-11 inhibition on ageing pathologies in older people.


Subject(s)
Aging , Interleukin-11 , Longevity , Signal Transduction , Animals , Female , Male , Mice , Aging/drug effects , Aging/genetics , Aging/metabolism , Aging/pathology , AMP-Activated Protein Kinases/metabolism , Frailty/genetics , Frailty/metabolism , Frailty/prevention & control , Inflammation/metabolism , Inflammation/drug therapy , Interleukin-11/antagonists & inhibitors , Interleukin-11/deficiency , Interleukin-11/genetics , Interleukin-11/metabolism , Interleukin-11 Receptor alpha Subunit/metabolism , Interleukin-11 Receptor alpha Subunit/deficiency , Longevity/drug effects , Longevity/genetics , Mechanistic Target of Rapamycin Complex 1/metabolism , Mechanistic Target of Rapamycin Complex 1/antagonists & inhibitors , Mice, Inbred C57BL , Signal Transduction/drug effects , Humans , Extracellular Signal-Regulated MAP Kinases/metabolism , Muscle, Skeletal/drug effects , Muscle, Skeletal/physiology
3.
Mol Metab ; 87: 101997, 2024 Sep.
Article in English | MEDLINE | ID: mdl-39032642

ABSTRACT

OBJECTIVE: Currently, little is known about the mechanism(s) regulating global and specific protein translation during metabolic dysfunction-associated steatohepatitis (MASH; previously known as non-alcoholic steatohepatitis, NASH). METHODS: Unbiased label-free quantitative proteome, puromycin-labelling and polysome profiling were used to understand protein translation activity in vitro and in vivo. RESULTS: We observed a global decrease in protein translation during lipotoxicity in human primary hepatocytes, mouse hepatic AML12 cells, and livers from a dietary mouse model of MASH. Interestingly, proteomic analysis showed that Rplp1, which regulates ribosome and translation pathways, was one of the most downregulated proteins. Moreover, decreased Esrra expression and binding to the Rplp1 promoter, diminished Rplp1 gene expression during lipotoxicity. This, in turn, reduced global protein translation and Esrra/Rplp1-dependent translation of lysosome (Lamp2, Ctsd) and autophagy (sqstm1, Map1lc3b) proteins. Of note, Esrra did not increase its binding to these gene promoters or their gene transcription, confirming its regulation of their translation during lipotoxicity. Notably, hepatic Esrra-Rplp1-dependent translation of lysosomal and autophagy proteins also was impaired in MASH patients and liver-specific Esrra knockout mice. Remarkably, alternate day fasting induced Esrra-Rplp1-dependent expression of lysosomal proteins, restored autophagy, and reduced lipotoxicity, inflammation, and fibrosis in hepatic cell culture and in vivo models of MASH. CONCLUSIONS: Esrra regulation of Rplp1-mediated translation of lysosome/autolysosome proteins was downregulated during MASH. Alternate day fasting activated this novel pathway and improved MASH, suggesting that Esrra and Rplp1 may serve as therapeutic targets for MASH. Our findings also provided the first example of a nuclear hormone receptor, Esrra, to not only regulate transcription but also protein translation, via induction of Rplp1.


Subject(s)
Fasting , Lysosomes , Non-alcoholic Fatty Liver Disease , Animals , Humans , Male , Mice , Autophagy , Fasting/metabolism , Hepatocytes/metabolism , Liver/metabolism , Lysosomes/metabolism , Mice, Inbred C57BL , Mice, Knockout , Non-alcoholic Fatty Liver Disease/metabolism , Non-alcoholic Fatty Liver Disease/genetics , Protein Biosynthesis , Ribosomal Proteins/metabolism , Ribosomal Proteins/genetics
4.
bioRxiv ; 2024 Jan 10.
Article in English | MEDLINE | ID: mdl-38260502

ABSTRACT

Protein translation is an energy-intensive ribosome-driven process that is reduced during nutrient scarcity to conserve cellular resources. During prolonged starvation, cells selectively translate specific proteins to enhance their survival (adaptive translation); however, this process is poorly understood. Accordingly, we analyzed protein translation and mRNA transcription by multiple methods in vitro and in vivo to investigate adaptive hepatic translation during starvation. While acute starvation suppressed protein translation in general, proteomic analysis showed that prolonged starvation selectively induced translation of lysosome and autolysosome proteins. Significantly, the expression of the orphan nuclear receptor, estrogen-related receptor alpha (Esrra) increased during prolonged starvation and served as a master regulator of this adaptive translation by transcriptionally stimulating 60S acidic ribosomal protein P1 (Rplp1) gene expression. Overexpression or siRNA knockdown of Esrra expression in vitro or in vivo led to parallel changes in Rplp1 gene expression, lysosome/autophagy protein translation, and autophagy. Remarkably, we have found that Esrra had dual functions by not only regulating transcription but also controling adaptive translation via the Esrra/Rplp1/lysosome/autophagy pathway during prolonged starvation.

5.
FEBS J ; 290(6): 1473-1476, 2023 03.
Article in English | MEDLINE | ID: mdl-36853086

ABSTRACT

Orphan nuclear receptor estrogen-related receptor alpha (ERRα) is an important regulator of energy metabolism, whereas its hyperactivation in breast cancer has been shown to regulate cell migration, proliferation, and tumour development. These findings suggest a fine balance in the status of ERRα in regulating metabolic homeostasis or promoting cancer progression. In this issue, Brindisi et al. have shown that ERRα is endogenously activated by cholesterol and caused breast cancer aggressiveness. This study also supports the anti-tumour mechanisms of cholesterol-lowering drugs such as statins.


Subject(s)
Breast Neoplasms , Humans , Female , Breast Neoplasms/drug therapy , Breast Neoplasms/genetics , Breast Neoplasms/metabolism , Cell Proliferation , Receptors, Estrogen/genetics , Receptors, Estrogen/metabolism , Cholesterol , Cell Line, Tumor , ERRalpha Estrogen-Related Receptor
6.
Biochim Biophys Acta Mol Basis Dis ; 1869(4): 166662, 2023 04.
Article in English | MEDLINE | ID: mdl-36754244

ABSTRACT

Nonalcoholic steatohepatitis (NASH) is considered a pivotal stage in nonalcoholic fatty liver disease (NAFLD) progression and increases the risk of end-stage liver diseases such as fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). The etiology of NASH is multifactorial and identifying reliable molecular players has proven difficult. Presently, there are no approved drugs for NASH treatment, which has become a leading cause of liver transplants worldwide. Here, using public human transcriptomic NAFLD dataset, we uncover Cystic fibrosis transmembrane conductance receptor (CFTR) as a differentially expressed gene in the livers of human NASH patients. Similarly, murine Cftr expression was also found to be upregulated in two mouse models of diet-induced NASH. Furthermore, the pharmacological inhibition of CFTR significantly reduced NASH progression in mice and its overexpression aggravated lipotoxicity in human hepatic cells. These results, thus, underscore the involvement of murine Cftr in the pathogenesis of NASH and raise the intriguing possibility of its pharmacological inhibition in human NASH.


Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , Non-alcoholic Fatty Liver Disease , Animals , Humans , Mice , Carcinoma, Hepatocellular/genetics , Cystic Fibrosis Transmembrane Conductance Regulator/genetics , Fibrosis , Liver Neoplasms/pathology , Non-alcoholic Fatty Liver Disease/drug therapy , Non-alcoholic Fatty Liver Disease/genetics , Non-alcoholic Fatty Liver Disease/metabolism
9.
Nat Commun ; 13(1): 5202, 2022 09 03.
Article in English | MEDLINE | ID: mdl-36057633

ABSTRACT

Spermidine is a natural polyamine that has health benefits and extends life span in several species. Deoxyhypusine synthase (DHPS) and deoxyhypusine hydroxylase (DOHH) are key enzymes that utilize spermidine to catalyze the post-translational hypusination of the translation factor EIF5A (EIF5AH). Here, we have found that hepatic DOHH mRNA expression is decreased in patients and mice with non-alcoholic steatohepatitis (NASH), and hepatic cells treated with fatty acids. The mouse and cell culture models of NASH have concomitant decreases in Eif5aH and mitochondrial protein synthesis which leads to lower mitochondrial activity and fatty acid ß-oxidation. Spermidine treatment restores EIF5AH, partially restores protein synthesis and mitochondrial function in NASH, and prevents NASH progression in vivo. Thus, the disrupted DHPS-DOHH-EIF5AH pathway during NASH represents a therapeutic target to increase hepatic protein synthesis and mitochondrial fatty acid oxidation (FAO) and prevent NASH progression.


Subject(s)
Non-alcoholic Fatty Liver Disease , Spermidine , Animals , Fatty Acids , Lysine/metabolism , Mice , Mitochondria/metabolism , Non-alcoholic Fatty Liver Disease/drug therapy , Non-alcoholic Fatty Liver Disease/genetics , Non-alcoholic Fatty Liver Disease/prevention & control , Peptide Initiation Factors/genetics , Peptide Initiation Factors/metabolism , Spermidine/pharmacology
10.
J Hepatol ; 77(5): 1246-1255, 2022 11.
Article in English | MEDLINE | ID: mdl-35820507

ABSTRACT

BACKGROUND & AIMS: Several recent clinical studies have shown that serum homocysteine (Hcy) levels are positively correlated, while vitamin B12 (B12) and folate levels are negative correlated, with non-alcoholic steatohepatitis (NASH) severity. However, it is not known whether hyperhomocysteinemia (HHcy) plays a pathogenic role in NASH. METHODS: We examined the effects of HHcy on NASH progression, metabolism, and autophagy in dietary and genetic mouse models, patients, and primates. We employed vitamin B12 (B12) and folate (Fol) to reverse NASH features in mice and cell culture. RESULTS: Serum Hcy correlated with hepatic inflammation and fibrosis in NASH. Elevated hepatic Hcy induced and exacerbated NASH. Gene expression of hepatic Hcy-metabolizing enzymes was downregulated in NASH. Surprisingly, we found increased homocysteinylation (Hcy-lation) and ubiquitination of multiple hepatic proteins in NASH including the key autophagosome/lysosome fusion protein, Syntaxin 17 (Stx17). This protein was Hcy-lated and ubiquitinated, and its degradation led to a block in autophagy. Genetic manipulation of Stx17 revealed its critical role in regulating autophagy, inflammation and fibrosis during HHcy. Remarkably, dietary B12/Fol, which promotes enzymatic conversion of Hcy to methionine, decreased HHcy and hepatic Hcy-lated protein levels, restored Stx17 expression and autophagy, stimulated ß -oxidation of fatty acids, and improved hepatic histology in mice with pre-established NASH. CONCLUSIONS: HHcy plays a key role in the pathogenesis of NASH via Stx17 homocysteinylation. B12/folate also may represent a novel first-line therapy for NASH. LAY SUMMARY: The incidence of non-alcoholic steatohepatitis, for which there are no approved pharmacological therapies, is increasing, posing a significant healthcare challenge. Herein, based on studies in mice, primates and humans, we found that dietary supplementation with vitamin B12 and folate could have therapeutic potential for the prevention or treatment of non-alcoholic steatohepatitis.


Subject(s)
Hyperhomocysteinemia , Non-alcoholic Fatty Liver Disease , Animals , Fatty Acids , Fibrosis , Folic Acid , Homocysteine , Humans , Inflammation , Methionine , Mice , Non-alcoholic Fatty Liver Disease/etiology , Non-alcoholic Fatty Liver Disease/prevention & control , Qa-SNARE Proteins , Vitamin B 12 , Vitamins
11.
Thyroid ; 32(6): 725-738, 2022 06.
Article in English | MEDLINE | ID: mdl-35317606

ABSTRACT

Background: Nonalcoholic steatohepatitis (NASH) is characterized by hepatic steatosis, lobular inflammation, and fibrosis. Thyroid hormone (TH) reduces steatosis; however, the therapeutic effect of TH on NASH-associated inflammation and fibrosis is not known. This study examined the therapeutic effect of TH on hepatic inflammation and fibrosis during NASH and investigated THs molecular actions on autophagy and mitochondrial biogenesis. Methods: HepG2-TRß cells were treated with bovine serum albumin-conjugated palmitic acid (PA) to mimic lipotoxic conditions in vitro. Mice with NASH were established by feeding C57BL/6J mice Western diet with 15% fructose in drinking water for 16 weeks. These mice were administered triiodothyronine (T3)/thyroxine (T4) supplemented in drinking water for the next eight weeks. Results: In cultured HepG2-TRß cells, TH treatment increased mitochondrial respiration and fatty acid oxidation under basal and PA-treated conditions, as well as decreased lipopolysaccharides and PA-stimulated inflammatory and fibrotic responses. In a dietary mouse model of NASH, TH administration decreased hepatic triglyceride content (3.19 ± 0.68 vs. 8.04 ± 0.42 mM/g liver) and hydroxyproline (1.44 ± 0.07 vs. 2.58 ± 0.30 mg/g liver) when compared with mice with untreated NASH. Metabolomics profiling of lipid metabolites showed that mice with NASH had increased triacylglycerol, diacylglycerol, monoacylglycerol, and hepatic cholesterol esters species, and these lipid species were decreased by TH treatment. Mice with NASH also showed decreased autophagic degradation as evidenced by decreased transcription Factor EB and lysosomal protease expression, and accumulation of LC3B-II and p62. TH treatment restored the level of lysosomal proteins and resolved the accumulation of LC3B-II and p62. Impaired mitochondrial biogenesis was also restored by TH. The simultaneous restoration of autophagy and mitochondrial biogenesis by TH increased ß-oxidation of fatty acids. Additionally, the elevated oxidative stress and inflammasome activation in NASH liver were also decreased by TH. Conclusions: In a mouse model of NASH, TH restored autophagy and mitochondrial biogenesis to increase ß-oxidation of fatty acids and to reduce lipotoxicity, oxidative stress, hepatic inflammation, and fibrosis. Activating thyroid hormone receptor in the liver may represent an effective strategy for NASH treatment.


Subject(s)
Drinking Water , Non-alcoholic Fatty Liver Disease , Animals , Disease Models, Animal , Drinking Water/metabolism , Fatty Acids/metabolism , Fibrosis , Humans , Inflammation/metabolism , Liver/metabolism , Mice , Mice, Inbred C57BL , Non-alcoholic Fatty Liver Disease/drug therapy , Non-alcoholic Fatty Liver Disease/metabolism , Thyroid Hormones/metabolism , Triglycerides/metabolism
12.
Autophagy ; 18(9): 2150-2160, 2022 09.
Article in English | MEDLINE | ID: mdl-35012409

ABSTRACT

Caffeine is among the most highly consumed substances worldwide, and it has been associated with decreased cardiovascular risk. Although caffeine has been shown to inhibit the proliferation of vascular smooth muscle cells (VSMCs), the mechanism underlying this effect is unknown. Here, we demonstrated that caffeine decreased VSMC proliferation and induced macroautophagy/autophagy in an in vivo vascular injury model of restenosis. Furthermore, we studied the effects of caffeine in primary human and mouse aortic VSMCs and immortalized mouse aortic VSMCs. Caffeine decreased cell proliferation, and induced autophagy flux via inhibition of MTOR signaling in these cells. Genetic deletion of the key autophagy gene Atg5, and the Sqstm1/p62 gene encoding a receptor protein, showed that the anti-proliferative effect by caffeine was dependent upon autophagy. Interestingly, caffeine also decreased WNT-signaling and the expression of two WNT target genes, Axin2 and Ccnd1 (cyclin D1). This effect was mediated by autophagic degradation of a key member of the WNT signaling cascade, DVL2, by caffeine to decrease WNT signaling and cell proliferation. SQSTM1/p62, MAP1LC3B-II and DVL2 were also shown to interact with each other, and the overexpression of DVL2 counteracted the inhibition of cell proliferation by caffeine. Taken together, our in vivo and in vitro findings demonstrated that caffeine reduced VSMC proliferation by inhibiting WNT signaling via stimulation of autophagy, thus reducing the vascular restenosis. Our findings suggest that caffeine and other autophagy-inducing drugs may represent novel cardiovascular therapeutic tools to protect against restenosis after angioplasty and/or stent placement.


Subject(s)
Autophagy , Muscle, Smooth, Vascular , Animals , Autophagy/physiology , Caffeine/metabolism , Caffeine/pharmacology , Cell Proliferation , Cells, Cultured , Humans , Mice , Muscle, Smooth, Vascular/metabolism , Myocytes, Smooth Muscle/metabolism , Sequestosome-1 Protein/metabolism , Wnt Signaling Pathway
13.
Biochim Biophys Acta Mol Basis Dis ; 1868(4): 166319, 2022 04 01.
Article in English | MEDLINE | ID: mdl-34954342

ABSTRACT

Non-alcoholic steatohepatitis (NASH) is a clinically important spectrum of non-alcoholic fatty liver disease (NAFLD) in humans. NASH is a stage of NAFLD progression wherein liver steatosis accompanies inflammation and pro-fibrotic events. Presently, there are no approved drugs for NASH, which has become a leading cause of liver transplant worldwide. To discover novel drug targets for NASH, we analyzed a human transcriptomic NASH dataset and found Aldo-keto reductase family 1 member B10 (AKR1B10) as a significantly upregulated gene in livers of human NASH patients. Similarly murine Akr1b10 and Aldo-keto reductase family 1 member B8 (Akr1b8) gene, which is a murine ortholog of human AKR1B10, were also found to be upregulated in a mouse model of diet-induced NASH. Furthermore, pharmacological inhibitors of AKR1B10 significantly reduced the pathological features of NASH such as steatosis, inflammation and fibrosis in mouse. In addition, genetic silencing of both mouse Akr1b10 and Akr1b8 significantly reduced the expression of proinflammatory cytokines from hepatocytes. These results, thus, underscore the involvement of murine AKR1B10 and AKR1B8 in the pathogenesis of murine NASH and raise an intriguing possibility of a similar role of AKR1B10 in human NASH.


Subject(s)
Alcohol Oxidoreductases/metabolism , Aldo-Keto Reductases/metabolism , Non-alcoholic Fatty Liver Disease/pathology , Alcohol Oxidoreductases/antagonists & inhibitors , Alcohol Oxidoreductases/genetics , Aldo-Keto Reductases/antagonists & inhibitors , Aldo-Keto Reductases/genetics , Animals , Anti-Inflammatory Agents, Non-Steroidal/therapeutic use , Cell Line , Cytokines/metabolism , Disease Models, Animal , Hepatocytes/cytology , Hepatocytes/metabolism , Humans , Liver/metabolism , Liver/pathology , Liver Cirrhosis/etiology , Liver Cirrhosis/prevention & control , Male , Mice , Mice, Inbred C57BL , Non-alcoholic Fatty Liver Disease/complications , Non-alcoholic Fatty Liver Disease/metabolism , RNA Interference , RNA, Small Interfering/metabolism , Sulindac/therapeutic use
14.
Mol Metab ; 53: 101266, 2021 11.
Article in English | MEDLINE | ID: mdl-34098145

ABSTRACT

OBJECTIVE: Nonalcoholic fatty liver disease (NAFLD) comprises a spectrum ranging from hepatosteatosis to progressive nonalcoholic steatohepatitis that can lead to cirrhosis. Humans with low levels of prohormone thyroxine (T4) have a higher incidence of NAFLD, and thyroid hormone treatment is very promising in all patients with NAFLD. Deiodinase type 1 (Dio1) is a hepatic enzyme that converts T4 to the bioactive T3 and therefore regulates thyroid hormone availability within hepatocytes. We investigated the role of this intrahepatic regulation during the progression of NAFLD. METHODS: We investigated hepatic thyroid hormone metabolism in two NAFLD models: wild-type mice fed a Western diet with fructose and Leprdb mice fed a methionine- and choline-deficient diet. AAV8-mediated liver-specific Dio1 knockdown was employed to investigate the role of Dio1 during the progression of NAFLD. Intrahepatic thyroid hormone levels, deiodinase activity, and metabolic parameters were measured. RESULTS: Dio1 expression and activity were increased in the early stages of NAFLD and were associated with an increased T3/T4 ratio. Prevention of this increase by AAV8-mediated liver-specific Dio1 knockdown increased hepatic triglycerides and cholesterol and decreased the pACC/ACC ratio and acylcarnitine levels, suggesting there was lower ß-oxidation. Dio1 siRNA KD in hepatic cells treated with fatty acids showed increased lipid accumulation and decreased oxidative phosphorylation. CONCLUSION: Hepatic Dio1 gene expression was modulated by dietary conditions, was increased during hepatosteatosis and early NASH, and regulated hepatic triglyceride content. These early adaptations likely represent compensatory mechanisms that reduce hepatosteatosis and prevent NASH progression.


Subject(s)
Hepatocytes/enzymology , Iodide Peroxidase/metabolism , Non-alcoholic Fatty Liver Disease/metabolism , Animals , Cells, Cultured , Iodide Peroxidase/deficiency , Iodide Peroxidase/genetics , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Mice, Transgenic , Non-alcoholic Fatty Liver Disease/pathology
15.
Nat Commun ; 12(1): 66, 2021 01 04.
Article in English | MEDLINE | ID: mdl-33397952

ABSTRACT

IL11 is important for fibrosis in non-alcoholic steatohepatitis (NASH) but its role beyond the stroma in liver disease is unclear. Here, we investigate the role of IL11 in hepatocyte lipotoxicity. Hepatocytes highly express IL11RA and secrete IL11 in response to lipid loading. Autocrine IL11 activity causes hepatocyte death through NOX4-derived ROS, activation of ERK, JNK and caspase-3, impaired mitochondrial function and reduced fatty acid oxidation. Paracrine IL11 activity stimulates hepatic stellate cells and causes fibrosis. In mouse models of NASH, hepatocyte-specific deletion of Il11ra1 protects against liver steatosis, fibrosis and inflammation while reducing serum glucose, cholesterol and triglyceride levels and limiting obesity. In mice deleted for Il11ra1, restoration of IL11 cis-signaling in hepatocytes reconstitutes steatosis and inflammation but not fibrosis. We found no evidence for the existence of IL6 or IL11 trans-signaling in hepatocytes or NASH. These data show that IL11 modulates hepatocyte metabolism and suggests a mechanism for NAFLD to NASH transition.


Subject(s)
Hepatocytes/metabolism , Interleukin-11/metabolism , Lipids/toxicity , Non-alcoholic Fatty Liver Disease/metabolism , Non-alcoholic Fatty Liver Disease/pathology , Signal Transduction , Adult , Animals , Autocrine Communication/drug effects , Cells, Cultured , Disease Models, Animal , Feeding Behavior , Hepatic Stellate Cells/drug effects , Hepatic Stellate Cells/metabolism , Hepatic Stellate Cells/pathology , Hepatocytes/drug effects , Hepatocytes/pathology , Humans , Interleukin-11 Receptor alpha Subunit/metabolism , Interleukin-6/metabolism , Mice, Knockout , Models, Biological , Paracrine Communication/drug effects , Phenotype , Signal Transduction/drug effects
16.
Hepatoma Res ; 7: 11, 2021.
Article in English | MEDLINE | ID: mdl-33490737

ABSTRACT

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent liver disorder worldwide. It comprises a spectrum of conditions that range from steatosis to non-alcoholic steatohepatitis, with progression to cirrhosis and hepatocellular carcinoma. Currently, there is no FDA-approved pharmacological treatment for NAFLD. The pathogenesis of NAFLD involves genetic and environmental/host factors, including those that cause changes in intestinal microbiota and their metabolites. In this review, we discuss recent findings on the relationship(s) of microbiota signature with severity of NAFLD and the role(s) microbial metabolites in NAFLD progression. We discuss how metabolites may affect NAFLD progression and their potential to serve as biomarkers for NAFLD diagnosis or therapeutic targets for disease management.

17.
STAR Protoc ; 1(2): 100064, 2020 09 18.
Article in English | MEDLINE | ID: mdl-33111102

ABSTRACT

Previously developed senescent primary fibroblast models have limited relevance to study age-related changes in metabolically active tissues such as the liver. Here, we describe a protocol to generate senescent cells from the mouse hepatic cell line, AML12. These senescent cells exhibit molecular and metabolic signatures that are similar to those observed in livers from aged mice. These senescent AML12 cells should be a useful in vitro model to study the metabolic effects of aging in the liver. For complete details on the use and execution of this protocol, please refer to Singh et al. (2020).


Subject(s)
Cell Culture Techniques/methods , Cell Separation/methods , Cellular Senescence/physiology , Hepatocytes/cytology , Liver/cytology , Animals , Cell Line , Mice
18.
Aging (Albany NY) ; 12(14): 13958-13978, 2020 07 26.
Article in English | MEDLINE | ID: mdl-32712601

ABSTRACT

Although aging in the liver contributes to the development of chronic liver diseases such as NAFLD and insulin resistance, little is known about the molecular and metabolic details of aging in hepatic cells. To examine these issues, we used sequential oxidative stress with hydrogen peroxide to induce premature senescence in AML12 hepatic cells. The senescent cells exhibited molecular and metabolic signatures, increased SA-ßGal and γH2A.X staining, and elevated senescence and pro-inflammatory gene expression that resembled livers from aged mice. Metabolic phenotyping showed fuel switching towards glycolysis and mitochondrial glutamine oxidation as well as impaired energy production. The senescent AML12 cells also had increased mTOR signaling and decreased autophagy which likely contributed to the fuel switching from ß-oxidation that occurred in normal AML12 cells. Additionally, senescence-associated secretory phenotype (SASP) proteins from conditioned media of senescent cells sensitized normal AML12 cells to palmitate-induced toxicity, a known pathological effect of hepatic aging. In summary, we have generated senescent AML12 cells which displayed the molecular hallmarks of aging and also exhibited the aberrant metabolic phenotype, mitochondrial function, and cell signaling that occur in the aged liver.


Subject(s)
Autophagy/physiology , Liver/growth & development , Liver/metabolism , Aging/metabolism , Animals , Cell Line , Cellular Senescence/physiology , Energy Metabolism/genetics , Energy Metabolism/physiology , Gene Expression Regulation , Glutamine/metabolism , Glycolysis , Hepatitis/metabolism , Hepatitis/pathology , Hepatocytes/metabolism , Lipid Metabolism/genetics , Lipid Metabolism/physiology , Liver/cytology , Male , Mice , Mice, Inbred C57BL , Oxidative Stress , Phenotype , TOR Serine-Threonine Kinases/biosynthesis , TOR Serine-Threonine Kinases/genetics
19.
Int J Mol Sci ; 21(5)2020 Feb 28.
Article in English | MEDLINE | ID: mdl-32121253

ABSTRACT

The estrogen-related receptor alpha (ESRRA) is an orphan nuclear receptor (NR) that significantly influences cellular metabolism. ESRRA is predominantly expressed in metabolically-active tissues and regulates the transcription of metabolic genes, including those involved in mitochondrial turnover and autophagy. Although ESRRA activity is well-characterized in several types of cancer, recent reports suggest that it also has an important role in metabolic diseases. This minireview focuses on the regulation of cellular metabolism and function by ESRRA and its potential as a target for the treatment of metabolic disorders.


Subject(s)
Metabolic Diseases/drug therapy , Molecular Targeted Therapy , Receptors, Estrogen/antagonists & inhibitors , Animals , Energy Metabolism , Humans , Oxidation-Reduction , Receptors, Estrogen/metabolism , ERRalpha Estrogen-Related Receptor
20.
Gastroenterology ; 157(3): 777-792.e14, 2019 09.
Article in English | MEDLINE | ID: mdl-31078624

ABSTRACT

BACKGROUND & AIMS: We studied the role of interleukin 11 (IL11) signaling in the pathogenesis of nonalcoholic steatohepatitis (NASH) using hepatic stellate cells (HSCs), hepatocytes, and mouse models of NASH. METHODS: We stimulated mouse and human fibroblasts, HSCs, or hepatocytes with IL11 and other cytokines and analyzed them by imaging, immunoblot, and functional assays and enzyme-linked immunosorbent assays. Mice were given injections of IL11. Mice with disruption of the interleukin 11 receptor subunit alpha1 gene (Il11ra1-/-) mice and Il11ra1+/+ mice were fed a high-fat methionine- and choline-deficient diet (HFMCD) or a Western diet with liquid fructose (WDF) to induce steatohepatitis; control mice were fed normal chow. db/db mice were fed with methionine- and choline-deficient diet for 12 weeks and C57BL/6 NTac were fed with HFMCD for 10 weeks or WDF for 16 weeks. Some mice were given intraperitoneal injections of anti-IL11 (X203), anti-IL11RA (X209), or a control antibody at different timepoints on the diets. Livers and blood were collected; blood samples were analyzed by biochemistry and liver tissues were analyzed by histology, RNA sequencing, immunoblots, immunohistochemistry, hydroxyproline, and mass cytometry time of flight assays. RESULTS: HSCs incubated with cytokines produced IL11, resulting in activation (phosphorylation) of ERK and expression of markers of fibrosis. Livers of mice given injections of IL11 became damaged, with increased markers of fibrosis, hepatocyte cell death and inflammation. Following the HFMCD or WDF, livers from Il11ra1-/- mice had reduced steatosis, fibrosis, expression of markers of inflammation and steatohepatitis, compared to and Il11ra1+/+ mice on the same diets. Depending on the time of administration of anti-IL11 or anti-IL11RA antibodies to wild-type mice on the HFMCD or WDF, or to db/db mice on the methionine and choline-deficient diet, the antibodies prevented, stopped, or reversed development of fibrosis and steatosis. Blood samples from Il11ra1+/+ mice fed the WDF and given injections of anti-IL11 or anti-IL11RA, as well as from Il11ra1-/- mice fed WDF, had lower serum levels of lipids and glucose than mice not injected with antibody or with disruption of Il11ra1. CONCLUSIONS: Neutralizing antibodies that block IL11 signaling reduce fibrosis, steatosis, hepatocyte death, inflammation and hyperglycemia in mice with diet-induced steatohepatitis. These antibodies also improve the cardiometabolic profile of mice and might be developed for the treatment of NASH.


Subject(s)
Antibodies, Neutralizing/pharmacology , Hepatitis/prevention & control , Interleukin-11 Receptor alpha Subunit/metabolism , Interleukin-11/antagonists & inhibitors , Liver Cirrhosis, Experimental/prevention & control , Liver/drug effects , Non-alcoholic Fatty Liver Disease/prevention & control , Animals , Cell Death/drug effects , Fibroblasts/drug effects , Fibroblasts/metabolism , Fibroblasts/pathology , Hepatic Stellate Cells/drug effects , Hepatic Stellate Cells/metabolism , Hepatic Stellate Cells/pathology , Hepatitis/genetics , Hepatitis/metabolism , Hepatitis/pathology , Hepatocytes/drug effects , Hepatocytes/metabolism , Hepatocytes/pathology , Humans , Inflammation Mediators/metabolism , Interleukin-11/metabolism , Interleukin-11 Receptor alpha Subunit/deficiency , Interleukin-11 Receptor alpha Subunit/genetics , Liver/metabolism , Liver/pathology , Liver Cirrhosis, Experimental/genetics , Liver Cirrhosis, Experimental/metabolism , Liver Cirrhosis, Experimental/pathology , Male , Mice, Inbred C57BL , Mice, Knockout , Non-alcoholic Fatty Liver Disease/genetics , Non-alcoholic Fatty Liver Disease/metabolism , Non-alcoholic Fatty Liver Disease/pathology , Signal Transduction/drug effects , THP-1 Cells
SELECTION OF CITATIONS
SEARCH DETAIL