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1.
Cell ; 175(5): 1289-1306.e20, 2018 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-30454647

RESUMEN

Obesity is a major driver of cancer, especially hepatocellular carcinoma (HCC). The prevailing view is that non-alcoholic steatohepatitis (NASH) and fibrosis or cirrhosis are required for HCC in obesity. Here, we report that NASH and fibrosis and HCC in obesity can be dissociated. We show that the oxidative hepatic environment in obesity inactivates the STAT-1 and STAT-3 phosphatase T cell protein tyrosine phosphatase (TCPTP) and increases STAT-1 and STAT-3 signaling. TCPTP deletion in hepatocytes promoted T cell recruitment and ensuing NASH and fibrosis as well as HCC in obese C57BL/6 mice that normally do not develop NASH and fibrosis or HCC. Attenuating the enhanced STAT-1 signaling prevented T cell recruitment and NASH and fibrosis but did not prevent HCC. By contrast, correcting STAT-3 signaling prevented HCC without affecting NASH and fibrosis. TCPTP-deletion in hepatocytes also markedly accelerated HCC in mice treated with a chemical carcinogen that promotes HCC without NASH and fibrosis. Our studies reveal how obesity-associated hepatic oxidative stress can independently contribute to the pathogenesis of NASH, fibrosis, and HCC.


Asunto(s)
Carcinoma Hepatocelular/patología , Neoplasias Hepáticas/patología , Enfermedad del Hígado Graso no Alcohólico/patología , Obesidad/patología , Factor de Transcripción STAT1/metabolismo , Factor de Transcripción STAT3/metabolismo , Animales , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Carcinoma Hepatocelular/metabolismo , Dieta Alta en Grasa , Modelos Animales de Enfermedad , Hepatocitos/metabolismo , Humanos , Hígado/metabolismo , Hígado/patología , Cirrosis Hepática/metabolismo , Cirrosis Hepática/patología , Neoplasias Hepáticas/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Obesidad/metabolismo , Estrés Oxidativo , Proteína Tirosina Fosfatasa no Receptora Tipo 2/deficiencia , Proteína Tirosina Fosfatasa no Receptora Tipo 2/genética , Proteína Tirosina Fosfatasa no Receptora Tipo 2/metabolismo , Transducción de Señal
2.
Mol Cell ; 82(8): 1528-1542.e10, 2022 04 21.
Artículo en Inglés | MEDLINE | ID: mdl-35245436

RESUMEN

Nonalcoholic fatty liver disease (NAFLD) is a global health concern with no approved drugs. High-protein dietary intervention is currently the most effective treatment. However, its underlying mechanism is unknown. Here, using Drosophila oenocytes, the specialized hepatocyte-like cells, we find that dietary essential amino acids ameliorate hepatic steatosis by inducing polyubiquitination of Plin2, a lipid droplet-stabilizing protein. Leucine and isoleucine, two branched-chain essential amino acids, strongly bind to and activate the E3 ubiquitin ligase Ubr1, targeting Plin2 for degradation. We further show that the amino acid-induced Ubr1 activity is necessary to prevent steatosis in mouse livers and cultured human hepatocytes, providing molecular insight into the anti-NAFLD effects of dietary protein/amino acids. Importantly, split-intein-mediated trans-splicing expression of constitutively active UBR2, an Ubr1 family member, significantly ameliorates obesity-induced and high fat diet-induced hepatic steatosis in mice. Together, our results highlight activation of Ubr1 family proteins as a promising strategy in NAFLD treatment.


Asunto(s)
Enfermedad del Hígado Graso no Alcohólico , Aminoácidos Esenciales/metabolismo , Aminoácidos Esenciales/farmacología , Aminoácidos Esenciales/uso terapéutico , Animales , Dieta Alta en Grasa/efectos adversos , Hepatocitos/metabolismo , Hígado/metabolismo , Ratones , Ratones Endogámicos C57BL , Enfermedad del Hígado Graso no Alcohólico/genética , Enfermedad del Hígado Graso no Alcohólico/prevención & control , Ubiquitinación
3.
Annu Rev Physiol ; 85: 363-381, 2023 02 10.
Artículo en Inglés | MEDLINE | ID: mdl-36260807

RESUMEN

Insulin action is impaired in type 2 diabetes. The functions of the hormone are an integrated product of insulin secretion from pancreatic ß-cells and insulin clearance by receptor-mediated endocytosis and degradation, mostly in liver (hepatocytes) and, to a lower extent, in extrahepatic peripheral tissues. Substantial evidence indicates that genetic or acquired abnormalities of insulin secretion or action predispose to type 2 diabetes. In recent years, along with the discovery of the molecular foundation of receptor-mediated insulin clearance, such as through the membrane glycoprotein CEACAM1, a consensus has begun to emerge that reduction of insulin clearance contributes to the disease process. In this review, we consider the evidence suggesting a pathogenic role for reduced insulin clearance in insulin resistance, obesity, hepatic steatosis, and type 2 diabetes.


Asunto(s)
Diabetes Mellitus Tipo 2 , Resistencia a la Insulina , Enfermedad del Hígado Graso no Alcohólico , Humanos , Insulina/metabolismo , Hígado/metabolismo , Obesidad , Enfermedad del Hígado Graso no Alcohólico/metabolismo
4.
Proc Natl Acad Sci U S A ; 120(4): e2217543120, 2023 Jan 24.
Artículo en Inglés | MEDLINE | ID: mdl-36669104

RESUMEN

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, in which prognosis is determined by liver fibrosis. A common variant in hydroxysteroid 17-beta dehydrogenase 13 (HSD17B13, rs72613567-A) is associated with a reduced risk of fibrosis in NAFLD, but the underlying mechanism(s) remains unclear. We investigated the effects of this variant in the human liver and in Hsd17b13 knockdown in mice by using a state-of-the-art metabolomics approach. We demonstrate that protection against liver fibrosis conferred by the HSD17B13 rs72613567-A variant in humans and by the Hsd17b13 knockdown in mice is associated with decreased pyrimidine catabolism at the level of dihydropyrimidine dehydrogenase. Furthermore, we show that hepatic pyrimidines are depleted in two distinct mouse models of NAFLD and that inhibition of pyrimidine catabolism by gimeracil phenocopies the HSD17B13-induced protection against liver fibrosis. Our data suggest pyrimidine catabolism as a therapeutic target against the development of liver fibrosis in NAFLD.


Asunto(s)
Enfermedad del Hígado Graso no Alcohólico , Animales , Humanos , Ratones , Hígado/metabolismo , Cirrosis Hepática/patología , Enfermedad del Hígado Graso no Alcohólico/patología , Pirimidinas/farmacología , Pirimidinas/metabolismo
5.
Annu Rev Pharmacol Toxicol ; 62: 155-175, 2022 01 06.
Artículo en Inglés | MEDLINE | ID: mdl-34516292

RESUMEN

While the uses of retinoids for cancer treatment continue to evolve, this review focuses on other therapeutic areas in which retinoids [retinol (vitamin A), all-trans retinoic acid (RA), and synthetic retinoic acid receptor (RAR)α-, ß-, and γ-selective agonists] are being used and on promising new research that suggests additional uses for retinoids for the treatment of disorders of the kidneys, skeletal muscles, heart, pancreas, liver, nervous system, skin, and other organs. The most mature area, in terms of US Food and Drug Administration-approved, RAR-selective agonists, is for treatment of various skin diseases. Synthetic retinoid agonists have major advantages over endogenous RAR agonists such as RA. Because they act through a specific RAR, side effects may be minimized, and synthetic retinoids often have better pharmaceutical properties than does RA. Based on our increasing knowledge of the multiple roles of retinoids in development, epigenetic regulation, and tissue repair, other exciting therapeutic areas are emerging.


Asunto(s)
Neoplasias , Retinoides , Epigénesis Genética , Humanos , Neoplasias/tratamiento farmacológico , Receptores de Ácido Retinoico/genética , Receptores de Ácido Retinoico/metabolismo , Receptores X Retinoide , Retinoides/farmacología , Retinoides/uso terapéutico , Estados Unidos
6.
FASEB J ; 38(18): e70061, 2024 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-39305120

RESUMEN

Indole is a microbial metabolite produced by the gut microbiota through the degradation of dietary tryptophan, known for its well-established anti-inflammatory and antioxidant properties. In this study, we collected fecal samples from mice fed a high-fat diet (HFD) and those on a standard diet (SD), then conducted 16S rRNA sequencing to analyze their gut microbiota. The analysis revealed distinct differences in the dominant bacterial species between the two groups, with a significant decrease in indole-producing probiotics in the HFD mice compared to the SD group. Then we administered oral indole treatment to male C57BL/6J mice with HFD-induced NAFLD and observed a significant improvement in hepatic steatosis and inflammation. Notably, indole alleviated the HFD-induced decline in serum Angiotensin-(1-7) [Ang-(1-7)] levels and Angiotensin-Converting Enzyme 2 (ACE2) expression. To further investigate the role of indole and ACE2 in NAFLD, we conducted experiments using ACE2 knockout (ACE2KO) mice that were also induced with HFD-induced NAFLD and treated with indole. Interestingly, the protective effects of indole were compromised in the absence of ACE2. In HepG2 cells, indole similarly stimulated ACE2 expression and, in an ACE2-dependent manner, reduced ROS generation, maintained mitochondrial membrane potential stability, and increased SIRT3 expression. In summary, our results highlight the formation of a biologically active gut-liver axis between the gut microbiota and the liver through the tryptophan metabolite indole, which mitigates NAFLD in an ACE2-dependent manner. Elevating dietary tryptophan and increasing indole levels may represent an effective approach for preventing and treating NAFLD.


Asunto(s)
Enzima Convertidora de Angiotensina 2 , Dieta Alta en Grasa , Microbioma Gastrointestinal , Indoles , Ratones Endogámicos C57BL , Enfermedad del Hígado Graso no Alcohólico , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Enfermedad del Hígado Graso no Alcohólico/tratamiento farmacológico , Animales , Enzima Convertidora de Angiotensina 2/metabolismo , Enzima Convertidora de Angiotensina 2/genética , Ratones , Masculino , Indoles/farmacología , Microbioma Gastrointestinal/efectos de los fármacos , Humanos , Dieta Alta en Grasa/efectos adversos , Ratones Noqueados , Hígado/metabolismo , Hígado/efectos de los fármacos , Fragmentos de Péptidos/metabolismo , Angiotensina I
7.
FASEB J ; 38(17): e70034, 2024 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-39248019

RESUMEN

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.


Asunto(s)
Hígado Graso , Hepatocitos , Gotas Lipídicas , Ratones Noqueados , Animales , Ratones , Gotas Lipídicas/metabolismo , Hepatocitos/metabolismo , Hígado Graso/metabolismo , Hígado Graso/patología , Hígado Graso/genética , 17-Hidroxiesteroide Deshidrogenasas/metabolismo , 17-Hidroxiesteroide Deshidrogenasas/genética , Metabolismo de los Lípidos , Peso Corporal , Hígado/metabolismo , Hígado/patología , Masculino , Ratones Endogámicos C57BL , Ácidos Grasos/metabolismo
8.
Proc Natl Acad Sci U S A ; 119(10): e2200083119, 2022 03 08.
Artículo en Inglés | MEDLINE | ID: mdl-35238641

RESUMEN

SignificanceWhile increasing evidence associates the disruption of circadian rhythms with pathologic conditions, including obesity, type 2 diabetes, and nonalcoholic fatty liver diseases (NAFLD), the involved mechanisms are still poorly described. Here, we show that, in both humans and mice, the pathogenesis of NAFLD is associated with the disruption of the circadian clock combined with perturbations of the growth hormone and sex hormone pathways. However, while this condition protects mice from the development of fibrosis and insulin resistance, it correlates with increased fibrosis in humans. This suggests that the perturbation of the circadian clock and its associated disruption of the growth hormone and sex hormone pathways are critical for the pathogenesis of metabolic and liver diseases.


Asunto(s)
Factores de Transcripción ARNTL/fisiología , Relojes Circadianos , Resistencia a la Insulina , Enfermedad del Hígado Graso no Alcohólico/etiología , Factores de Transcripción ARNTL/genética , Animales , Dieta Alta en Grasa , Eliminación de Gen , Regulación de la Expresión Génica , Humanos , Leptina/genética , Metabolismo de los Lípidos/genética , Masculino , Ratones , Ratones Noqueados , Enfermedad del Hígado Graso no Alcohólico/genética , Obesidad/genética
9.
Semin Cancer Biol ; 93: 20-35, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37149203

RESUMEN

Hepatocellular carcinoma (HCC) is estimated to be the third leading cause of cancer-related mortality and is characterized by low survival rates. Nonalcoholic fatty liver disease (NAFLD) is emerging as a leading cause of HCC, whose rates are increasing, owing to the increasing prevalence of NAFLD. The pathogenesis of NAFLD-associated HCC is multifactorial: insulin resistance, obesity, diabetes and the low-grade hepatic inflammation, which characterizes NAFLD, seem to play key roles in the development and progression of HCC. The diagnosis of NAFLD-associated HCC is based on imaging in the presence of liver cirrhosis, preferably computerized tomography or magnetic resonance imaging, but liver biopsy for histological confirmation is usually required in the absence of liver cirrhosis. Some preventive measures have been recommended for NAFLD-associated HCC, including weight loss, cessation of even moderate alcohol drinking and smoking, as well as the use of metformin, statins and aspirin. However, these preventive measures are mainly based on observational studies, thus they need validation in trials of different design before introducing in clinical practice. The treatment of NAFLD should be tailored on an individual basis and should be ideally determined by a multidisciplinary team. In the last two decades, new medications, including tyrosine kinase inhibitors and immune checkpoints inhibitors, have improved the survival of patients with advanced HCC, but trials specifically designed for patients with NAFLD-associated HCC are scarce. The aim of this review was to overview evidence on the epidemiology and pathophysiology of NAFLD-associated HCC, then to comment on imaging tools for its appropriate screening and diagnosis, and finally to critically summarize the currently available options for its prevention and treatment.


Asunto(s)
Carcinoma Hepatocelular , Neoplasias Hepáticas , Enfermedad del Hígado Graso no Alcohólico , Humanos , Carcinoma Hepatocelular/diagnóstico , Carcinoma Hepatocelular/epidemiología , Carcinoma Hepatocelular/etiología , Enfermedad del Hígado Graso no Alcohólico/complicaciones , Enfermedad del Hígado Graso no Alcohólico/diagnóstico por imagen , Enfermedad del Hígado Graso no Alcohólico/epidemiología , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/epidemiología , Neoplasias Hepáticas/etiología , Progresión de la Enfermedad , Cirrosis Hepática/complicaciones , Cirrosis Hepática/patología
10.
Med Res Rev ; 44(2): 568-586, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37899676

RESUMEN

Nonalcoholic fatty liver disease, also called metabolic dysfunction-associated steatotic liver disease, is the most common liver disease worldwide and has no approved pharmacotherapy. Due to its beneficial effects on metabolic regulation, inflammation suppression, cell death prevention, and fibrogenesis inhibition, farnesoid X receptor (FXR) is widely accepted as a promising therapeutic target for nonalcoholic steatosis (NASH) or called metabolic dysfunction-associated steatohepatitis (MASH). Many FXR agonists have been developed for NASH/MASH therapy. Obeticholic acid (OCA) is the pioneering frontrunner FXR agonist and the first demonstrating success in clinical trials. Unfortunately, OCA did not receive regulatory approval as a NASH pharmacotherapy because its moderate benefits did not outweigh its safety risks, which may cast a shadow over FXR-based drug development for NASH/MASH. This review summarizes the milestones in the development of OCA for NASH/MASH and discuss its limitations, including moderate hepatoprotection and the undesirable side effects of dyslipidemia, pruritus, cholelithiasis, and liver toxicity risk, in depth. More importantly, we provide perspectives on FXR-based therapy for NASH/MASH, hoping to support a successful bench-to-clinic transition.


Asunto(s)
Enfermedad del Hígado Graso no Alcohólico , Humanos , Enfermedad del Hígado Graso no Alcohólico/tratamiento farmacológico , Ácido Quenodesoxicólico/farmacología , Ácido Quenodesoxicólico/uso terapéutico
11.
J Lipid Res ; 65(7): 100580, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38901559

RESUMEN

This study aimed to determine whether obese men with nonalcoholic fatty liver disease (NAFLD) display differences between those with simple steatosis versus steatohepatitis (NASH) in splanchnic and hepatic FFA and VLDL-triglycerides (VLDL-TG) balances. The study involved 17 obese men with biopsy-proven NAFLD (9 with NASH and 8 with simple steatosis). We used hepatic vein catheterization in combination with [3H]palmitate and [14C]VLDL-TG tracers to measure splanchnic palmitate and VLDL-TG uptake and release rates during basal and hyperinsulinemic conditions. Indocyanine green was used to measure splanchnic plasma flow. Splanchnic palmitate uptake was similar in the two groups and significantly reduced during hyperinsulinemia (NASH: 62 (48-77) versus 38 (18-58) µmol/min; simple steatosis: 62 (46-78) versus 45 (25-65) µmol/min, mean (95% CI), basal versus clamp periods, respectively, P = 0.02 time-effect). Splanchnic palmitate release was also comparable between groups and nonsignificantly diminished during hyperinsulinemia. The percent palmitate delivered to the liver originating from visceral adipose tissue lipolysis was similar and unchanged by hyperinsulinemia. Splanchnic uptake and release of VLDL-TG were similar between groups. Hyperinsulinemia suppressed VLDL-TG release (P <0.05 time-effect) in both groups. Insulin-mediated glucose disposal was similar in the two groups (P = 0.54). Obese men with NASH and simple steatosis have similar splanchnic uptake and release of FFA and VLDL-TG and a similar proportion of FFA from visceral adipose tissue lipolysis delivered to the liver. These results demonstrate that the splanchnic balances of FFA and VLDL-TG do not differ between obese men with NASH and those with simple steatosis.


Asunto(s)
Insulina , Lipoproteínas VLDL , Enfermedad del Hígado Graso no Alcohólico , Triglicéridos , Humanos , Masculino , Lipoproteínas VLDL/metabolismo , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Enfermedad del Hígado Graso no Alcohólico/patología , Persona de Mediana Edad , Triglicéridos/metabolismo , Triglicéridos/sangre , Insulina/metabolismo , Ácidos Grasos no Esterificados/metabolismo , Ácidos Grasos no Esterificados/sangre , Adulto , Hígado Graso/metabolismo , Hígado Graso/patología , Hígado/metabolismo , Obesidad/metabolismo , Obesidad/complicaciones
12.
J Lipid Res ; 65(6): 100558, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38729350

RESUMEN

Metabolic dysfunction-associated steatotic liver disease is the most common form of liver disease and poses significant health risks to patients who progress to metabolic dysfunction-associated steatohepatitis. Fatty acid overload alters endoplasmic reticulum (ER) calcium stores and induces mitochondrial oxidative stress in hepatocytes, leading to hepatocellular inflammation and apoptosis. Obese mice have impaired liver sarco/ER Ca2+-ATPase (SERCA) function, which normally maintains intracellular calcium homeostasis by transporting Ca2+ ions from the cytoplasm to the ER. We hypothesized that restoration of SERCA activity would improve diet-induced steatohepatitis in mice by limiting ER stress and mitochondrial dysfunction. WT and melanocortin-4 receptor KO (Mc4r-/-) mice were placed on either chow or Western diet (WD) for 8 weeks. Half of the WD-fed mice were administered CDN1163 to activate SERCA, which reduced liver fibrosis and inflammation. SERCA activation also restored glucose tolerance and insulin sensitivity, improved histological markers of metabolic dysfunction-associated steatohepatitis, increased expression of antioxidant enzymes, and decreased expression of oxidative stress and ER stress genes. CDN1163 decreased hepatic citric acid cycle flux and liver pyruvate cycling, enhanced expression of mitochondrial respiratory genes, and shifted hepatocellular [NADH]/[NAD+] and [NADPH]/[NADP+] ratios to a less oxidized state, which was associated with elevated PUFA content of liver lipids. In sum, the data demonstrate that pharmacological SERCA activation limits metabolic dysfunction-associated steatotic liver disease progression and prevents metabolic dysfunction induced by WD feeding in mice.


Asunto(s)
Hígado , ATPasas Transportadoras de Calcio del Retículo Sarcoplásmico , Animales , ATPasas Transportadoras de Calcio del Retículo Sarcoplásmico/metabolismo , Ratones , Hígado/metabolismo , Hígado/patología , Masculino , Hígado Graso/metabolismo , Hígado Graso/patología , Estrés del Retículo Endoplásmico , Ratones Endogámicos C57BL , Estrés Oxidativo/efectos de los fármacos , Dieta Occidental/efectos adversos , Ratones Noqueados
13.
J Proteome Res ; 23(6): 2253-2264, 2024 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-38698681

RESUMEN

Nonalcoholic fatty liver disease (NAFLD) has emerged as the predominant chronic liver condition globally, and underdiagnosis is common, particularly in mild cases, attributed to the asymptomatic nature and traditional ultrasonography's limited sensitivity to detect early-stage steatosis. Consequently, patients may experience progressive liver pathology. The objective of this research is to ascertain the efficacy of serum glycan glycopatterns as a potential diagnostic biomarker, with a particular focus on the disease's early stages. We collected a total of 170 serum samples from volunteers with mild-NAFLD (Mild), severe-NAFLD (Severe), and non-NAFLD (None). Examination via lectin microarrays has uncovered pronounced disparities in serum glycopatterns identified by 19 distinct lectins. Following this, we employed four distinct machine learning algorithms to categorize the None, Mild, and Severe groups, drawing on the alterations observed in serum glycopatterns. The gradient boosting decision tree (GBDT) algorithm outperformed other models in diagnostic accuracy within the validation set, achieving an accuracy rate of 95% in differentiating the None group from the Mild group. Our research indicates that employing lectin microarrays to identify alterations in serum glycopatterns, when integrated with advanced machine learning algorithms, could constitute a promising approach for the diagnosis of NAFLD, with a special emphasis on its early detection.


Asunto(s)
Biomarcadores , Lectinas , Aprendizaje Automático , Enfermedad del Hígado Graso no Alcohólico , Humanos , Enfermedad del Hígado Graso no Alcohólico/sangre , Enfermedad del Hígado Graso no Alcohólico/diagnóstico , Biomarcadores/sangre , Lectinas/sangre , Femenino , Masculino , Adulto , Persona de Mediana Edad , Algoritmos , Polisacáridos/sangre , Polisacáridos/química , Glicoproteínas/sangre
14.
J Biol Chem ; 299(9): 105162, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37586586

RESUMEN

Sphingomyelin synthase (SMS)-related protein (SMSr) is a phosphatidylethanolamine phospholipase C (PE-PLC) that is conserved and ubiquitous in mammals. However, its biological function is still not clear. We previously observed that SMS1 deficiency-mediated glucosylceramide accumulation caused nonalcoholic fatty liver diseases (NAFLD), including nonalcoholic steatohepatitis (NASH) and liver fibrosis. Here, first, we evaluated high-fat diet/fructose-induced NAFLD in Smsr KO and WT mice. Second, we evaluated whether SMSr deficiency can reverse SMS1 deficiency-mediated NAFLD, using Sms1/Sms2 double and Sms1/Sms2/Smsr triple KO mice. We found that SMSr/PE-PLC deficiency attenuated high-fat diet/fructose-induced fatty liver and NASH, and attenuated glucosylceramide accumulation-induced NASH, fibrosis, and tumor formation. Further, we found that SMSr/PE-PLC deficiency reduced the expression of many inflammatory cytokines and fibrosis-related factors, and PE supplementation in vitro or in vivo mimicked the condition of SMSr/PE-PLC deficiency. Furthermore, we demonstrated that SMSr/PE-PLC deficiency or PE supplementation effectively prevented membrane-bound ß-catenin transfer to the nucleus, thereby preventing tumor-related gene expression. Finally, we observed that patients with NASH had higher SMSr protein levels in the liver, lower plasma PE levels, and lower plasma PE/phosphatidylcholine ratios, and that human plasma PE levels are negatively associated with tumor necrosis factor-α and transforming growth factor ß1 levels. In conclusion, SMSr/PE-PLC deficiency causes PE accumulation, which can attenuate fatty liver, NASH, and fibrosis. These results suggest that SMSr/PE-PLC inhibition therapy may mitigate NAFLD.


Asunto(s)
Neoplasias , Enfermedad del Hígado Graso no Alcohólico , Transferasas (Grupos de Otros Fosfatos Sustitutos) , Animales , Humanos , Ratones , Fructosa/efectos adversos , Glucosilceramidas/metabolismo , Hígado/metabolismo , Cirrosis Hepática/patología , Neoplasias/genética , Neoplasias/metabolismo , Enfermedad del Hígado Graso no Alcohólico/genética , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Fosfatidiletanolaminas/sangre , Transferasas (Grupos de Otros Fosfatos Sustitutos)/genética , Transferasas (Grupos de Otros Fosfatos Sustitutos)/metabolismo , Ratones Noqueados , Masculino , Femenino , Dieta Alta en Grasa/efectos adversos
15.
J Biol Chem ; 299(3): 102937, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36690274

RESUMEN

Defective autophagy and lipotoxicity are the hallmarks of nonalcoholic fatty liver disease. However, the precise molecular mechanism for the defective autophagy in lipotoxic conditions is not fully known. In the current study, we elucidated that activation of the mammalian target of rapamycin complex 1 (mTORC1)-G9a-H3K9me2 axis in fatty acid-induced lipotoxicity blocks autophagy by repressing key autophagy genes. The fatty acid-treated cells show mTORC1 activation, increased histone methyltransferase G9a levels, and suppressed autophagy as indicated by increased accumulation of the key autophagic cargo SQSTM1/p62 and decreased levels of autophagy-related proteins LC3II, Beclin1, and Atg7. Our chromatin immunoprecipitation analysis showed that decrease in autophagy was associated with increased levels of the G9a-mediated repressive H3K9me2 mark and decreased RNA polymerase II occupancy at the promoter regions of Beclin1 and Atg7 in fatty acid-treated cells. Inhibition of mTORC1 in fatty acid-treated cells decreased G9a-mediated H3K9me2 occupancy and increased polymerase II occupancy at Beclin1 and Atg7 promoters. Furthermore, mTORC1 inhibition increased the expression of Beclin1 and Atg7 in fatty acid-treated cells and decreased the accumulation of SQSTM1/p62. Interestingly, the pharmacological inhibition of G9a alone in fatty acid-treated cells decreased the H3K9me2 mark at Atg7 and Beclin1 promoters and restored the expression of Atg7 and Beclin1. Taken together, our findings have identified the mTORC1-G9a-H3K9me2 axis as a negative regulator of the autophagy pathway in hepatocellular lipotoxicity and suggest that the G9a-mediated epigenetic repression is mechanistically a key step during the repression of autophagy in lipotoxic conditions.


Asunto(s)
Autofagia , Ácidos Grasos , Histona Metiltransferasas , Histonas , Diana Mecanicista del Complejo 1 de la Rapamicina , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Histonas/metabolismo , Ácidos Grasos/toxicidad , Autofagia/fisiología , Epigénesis Genética , Histona Metiltransferasas/metabolismo , Hepatocitos/fisiología , Células Hep G2 , Regulación de la Expresión Génica/efectos de los fármacos , Palmitatos/toxicidad , Beclina-1/genética , Beclina-1/metabolismo , Regiones Promotoras Genéticas , Autofagosomas/genética , Autofagosomas/metabolismo , Humanos
16.
J Biol Chem ; 299(2): 102835, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36581203

RESUMEN

Tetraspanins are transmembrane signaling and proinflammatory proteins. Prior work demonstrates that the tetraspanin, CD53/TSPAN25/MOX44, mediates B-cell development and lymphocyte migration to lymph nodes and is implicated in various inflammatory diseases. However, CD53 is also expressed in highly metabolic tissues, including adipose and liver; yet its function outside the lymphoid compartment is not defined. Here, we show that CD53 demarcates the nutritional and inflammatory status of hepatocytes. High-fat exposure and inflammatory stimuli induced CD53 in vivo in liver and isolated primary hepatocytes. In contrast, restricting hepatocyte glucose flux through hepatocyte glucose transporter 8 deletion or through trehalose treatment blocked CD53 induction in fat- and fructose-exposed contexts. Furthermore, germline CD53 deletion in vivo blocked Western diet-induced dyslipidemia and hepatic inflammatory transcriptomic activation. Surprisingly, metabolic protection in CD53 KO mice was more pronounced in the presence of an inciting inflammatory event. CD53 deletion attenuated tumor necrosis factor alpha-induced and fatty acid + lipopolysaccharide-induced cytokine gene expression and hepatocyte triglyceride accumulation in isolated murine hepatocytes. In vivo, CD53 deletion in nonalcoholic steatohepatitis diet-fed mice blocked peripheral adipose accumulation and adipose inflammation, insulin tolerance, and liver lipid accumulation. We then defined a stabilized and trehalase-resistant trehalose polymer that blocks hepatocyte CD53 expression in basal and over-fed contexts. The data suggest that CD53 integrates inflammatory and metabolic signals in response to hepatocyte nutritional status and that CD53 blockade may provide a means by which to attenuate pathophysiology in diseases that integrate overnutrition and inflammation, such as nonalcoholic steatohepatitis and type 2 diabetes.


Asunto(s)
Hepatocitos , Enfermedad del Hígado Graso no Alcohólico , Tetraspanina 25 , Animales , Ratones , Dieta Alta en Grasa , Hepatocitos/metabolismo , Inflamación/genética , Inflamación/metabolismo , Hígado/metabolismo , Ratones Endogámicos C57BL , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Obesidad/metabolismo , Tetraspanina 25/metabolismo , Tetraspaninas/genética , Tetraspaninas/metabolismo , Trehalosa/metabolismo
17.
Curr Issues Mol Biol ; 46(6): 5965-5983, 2024 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-38921027

RESUMEN

Hepatocellular carcinoma (HCC) represents a significant burden on global healthcare systems due to its considerable incidence and mortality rates. Recent trends indicate an increase in the worldwide incidence of metabolic dysfunction-associated steatotic liver disease (MASLD) and a shift in the etiology of HCC, with MASLD replacing the hepatitis B virus as the primary contributor to new cases of HCC. MASLD-related HCC exhibits distinct characteristics compared to viral HCC, including unique immune cell profiles resulting in an overall more immunosuppressive or exhausted tumor microenvironment. Furthermore, MASLD-related HCC is frequently identified in older age groups and among individuals with cardiometabolic comorbidities. Additionally, a greater percentage of MASLD-related HCC cases occur in noncirrhotic patients compared to those with viral etiologies, hindering early detection. However, the current clinical practice guidelines lack specific recommendations for the screening of HCC in MASLD patients. The evolving landscape of HCC management offers a spectrum of therapeutic options, ranging from surgical interventions and locoregional therapies to systemic treatments, for patients across various stages of the disease. Despite ongoing debates, the current evidence does not support differences in optimal treatment modalities based on etiology. In this study, we aimed to provide a comprehensive overview of the current literature on the trends, characteristics, clinical implications, and treatment modalities for MASLD-related HCC.

18.
Cancer ; 2024 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-39238423

RESUMEN

BACKGROUND: Steatotic liver disease (SLD) is an emerging liver disease that has been associated with an increased risk for hepatocellular carcinoma (HCC). The impact of concurrent SLD on the prognosis of HCC remains unknown. This study investigates how concurrent SLD affects the outcomes of patients with HCC undergoing curative radiofrequency ablation (RFA) therapy. METHODS: A retrospective analysis of patients with early-stage HCC receiving curative RFA at a tertiary medical center was conducted. Laboratory data and HCC characteristics were recorded and analyzed by a Cox proportional hazards regression model to predict recurrence and all-cause mortality after RFA. RESULTS: A total of 598 patients with HCC were included between 2005 and 2015, with 139 and 459 classified in SLD and non-SLD groups, respectively. The SLD group exhibited a significantly better liver reserve and a lower cumulative incidence of HCC recurrence and liver-related and all-cause mortality after a median follow-up of 51 months. After adjusting for metabolic dysfunction, liver reserve, and HCC characteristics, the presence of SLD reduced all-cause mortality (adjusted hazard ratio [aHR], 0.67; 95% confidence interval [CI], 0.45-0.996; p = .048), which was supported by inverse probability weighting analysis (aHR, 0.65; 95% CI, 0.42-1.00; p = .049). Poor liver functional reserve (high albumin-bilirubin grades) increased all-cause mortality dose dependently. Barcelona Clinic Liver Cancer staging and a higher Fibrosis-4 index were predictors for HCC recurrence, whereas SLD was not. CONCLUSIONS: Among patients with HCC undergoing curative RFA, those with concurrent SLD had a lower risk of all-cause mortality compared to those with poor liver functional reserve. PLAIN LANGUAGE SUMMARY: The present research demonstrated that patients with both liver cancer and steatotic liver disease who received curative radiofrequency ablation for liver cancer survived longer compared to those without steatotic liver disease. Maintaining good liver function is an important prognostic factor for survival.

19.
Annu Rev Med ; 73: 529-544, 2022 01 27.
Artículo en Inglés | MEDLINE | ID: mdl-34809436

RESUMEN

Nonalcoholic fatty liver disease (NAFLD) is a major public health crisis affecting approximately 25% of the world's population. The spectrum of NAFLD ranges from bland steatosis to steatohepatitis with fibrosis; eventual development of cirrhosis in a subgroup of patients now represents the leading indication for liver transplant in women and in individuals older than 65. The development of noninvasive liver disease assessment tools has led to substantial progress in the diagnosis of NAFLD. Patients with NAFLD are at increased risk of cardiometabolic disease, which should therefore be an important part of the therapeutic approach. This review focuses on diagnosis and risk stratification of NAFLD across the full spectrum of disease, including important considerations in the approach to patients with cirrhosis.


Asunto(s)
Trasplante de Hígado , Enfermedad del Hígado Graso no Alcohólico , Femenino , Fibrosis , Humanos , Cirrosis Hepática/diagnóstico , Enfermedad del Hígado Graso no Alcohólico/diagnóstico , Enfermedad del Hígado Graso no Alcohólico/epidemiología , Enfermedad del Hígado Graso no Alcohólico/terapia
20.
Clin Gastroenterol Hepatol ; 22(1): 81-90.e4, 2024 01.
Artículo en Inglés | MEDLINE | ID: mdl-37406954

RESUMEN

BACKGROUND & AIMS: Nonalcoholic fatty liver disease (NAFLD)-related fibrosis is heritable, but it is unclear how family history may be used to identify first-degree relatives with advanced fibrosis. We aimed to develop and validate a simple risk score to identify first-degree relatives of probands who have undergone assessment of liver fibrosis who are at higher risk of NAFLD with advanced fibrosis. METHODS: This prospective, cross-sectional, familial study consisted of a derivation cohort from San Diego, California, and a validation cohort from Helsinki, Finland. This study included consecutive adult probands (n = 242) with NAFLD and advanced fibrosis, NAFLD without advanced fibrosis, and non-NAFLD, with at least 1 of their first-degree relatives. All included probands and first-degree relatives underwent evaluation of liver fibrosis, the majority by magnetic resonance elastography. RESULTS: A total of 396 first-degree relatives (64% male) were included. The median age and body mass index were 47 years (interquartile range, 32-62 y) and 27.6 kg/m2 (interquartile range, 24.1-32.5 kg/m2), respectively. Age (1 point), type 2 diabetes (1 point), obesity (2 points), and proband with NAFLD and advanced fibrosis (2 points) were predictors of advanced fibrosis among first-degree relatives in the derivation cohort (n = 220) and formed the NAFLD Familial Risk Score. The area under the receiver operator characteristic curve of the NAFLD Familial Risk Score for detecting advanced fibrosis was 0.94 in the validation cohort (n = 176). The NAFLD Familial Risk Score outperformed the Fibrosis-4 index in the validation cohort (area under the receiver operator characteristic curve, 0.94 vs 0.70; P = .02). CONCLUSIONS: The NAFLD Familial Risk Score is a simple and accurate clinical tool to identify advanced fibrosis in first-degree relatives. These data may have implications for surveillance in NAFLD.


Asunto(s)
Diabetes Mellitus Tipo 2 , Enfermedad del Hígado Graso no Alcohólico , Adulto , Humanos , Masculino , Femenino , Enfermedad del Hígado Graso no Alcohólico/diagnóstico , Enfermedad del Hígado Graso no Alcohólico/patología , Estudios Transversales , Estudios Prospectivos , Factores de Riesgo , Cirrosis Hepática/diagnóstico , Cirrosis Hepática/patología , Predisposición Genética a la Enfermedad , Hígado/patología , Biopsia
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