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1.
Int J Mol Sci ; 24(15)2023 07 26.
Article in English | MEDLINE | ID: mdl-37569315

ABSTRACT

Acute intermittent porphyria (AIP) is a metabolic disorder caused by mutations in the porphobilinogen deaminase (PBGD) gene, encoding the third enzyme of the heme synthesis pathway. Although AIP is characterized by low clinical penetrance (~1% of PBGD mutation carriers), patients with clinically stable disease report chronic symptoms and frequently show insulin resistance. This study aimed to evaluate the beneficial impact of nutritional interventions on correct carbohydrate dysfunctions in a mouse model of AIP that reproduces insulin resistance and altered glucose metabolism. The addition of spores of Bacillus coagulans in drinking water for 12 weeks modified the gut microbiome composition in AIP mice, ameliorated glucose tolerance and hyperinsulinemia, and stimulated fat disposal in adipose tissue. Lipid breakdown may be mediated by muscles burning energy and heat dissipation by brown adipose tissue, resulting in a loss of fatty tissue and improved lean/fat tissue ratio. Probiotic supplementation also improved muscle glucose uptake, as measured using Positron Emission Tomography (PET) analysis. In conclusion, these data provide a proof of concept that probiotics, as a dietary intervention in AIP, induce relevant changes in intestinal bacteria composition and improve glucose uptake and muscular energy utilization. Probiotics may offer a safe, efficient, and cost-effective option to manage people with insulin resistance associated with AIP.


Subject(s)
Bacillus coagulans , Hyperinsulinism , Insulin Resistance , Porphyria, Acute Intermittent , Mice , Animals , Porphyria, Acute Intermittent/genetics , Porphyria, Acute Intermittent/therapy , Porphyria, Acute Intermittent/diagnosis , Hydroxymethylbilane Synthase/genetics , Hyperinsulinism/therapy , Glucose
2.
Pharmaceutics ; 15(4)2023 Apr 10.
Article in English | MEDLINE | ID: mdl-37111688

ABSTRACT

Type 2 diabetes (T2D) is a complex metabolic disease, which involves maintained hyperglycemia, mainly due to the development of an insulin resistance process. Metformin administration is the most prescribed treatment for diabetic patients. In a previously published study, we demonstrated that Pediococcus acidilactici pA1c® (pA1c) protects from insulin resistance and body weight gain in HFD-induced diabetic mice. The present work aimed to evaluate the possible beneficial impact of a 16-week administration of pA1c, metformin, or the combination of pA1c and metformin in a T2D HFD-induced mice model. We found that the simultaneous administration of both products attenuated hyperglycemia, increased high-intensity insulin-positive areas in the pancreas and HOMA-ß, decreased HOMA-IR and also provided more beneficial effects than metformin treatment (regarding HOMA-IR, serum C-peptide level, liver steatosis or hepatic Fasn expression), and pA1c treatment (regarding body weight or hepatic G6pase expression). The three treatments had a significant impact on fecal microbiota and led to differential composition of commensal bacterial populations. In conclusion, our findings suggest that P. acidilactici pA1c® administration improved metformin beneficial effects as a T2D treatment, and it would be a valuable therapeutic strategy to treat T2D.

3.
Nutrients ; 14(24)2022 Dec 07.
Article in English | MEDLINE | ID: mdl-36558371

ABSTRACT

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease, reaching epidemic proportions worldwide. Targeting the gut-adipose tissue-liver axis by modulating the gut microbiota can be a promising therapeutic approach in NAFLD. Lactiplantibacillus plantarum, a potent lactic-acid-producing bacterium, has been shown to attenuate NAFLD. However, to our knowledge, the possible effect of the Lactiplantibacillus plantarum strain DSM20174 (L.p. DSM20174) on the gut-adipose tissue axis, diminishing inflammatory mediators as fuel for NAFLD progression, is still unknown. Using a NAFLD mouse model fed a high-fat, high-fructose (HFHF) diet for 10 weeks, we show that L.p DSM20174 supplementation of HFHF mice prevented weight gain, improved glucose and lipid homeostasis, and reduced white adipose inflammation and NAFLD progression. Furthermore, 16S rRNA gene sequencing of the faecal microbiota suggested that treatment of HFHF-fed mice with L.p DSM20174 changed the diversity and altered specific bacterial taxa at the levels of family, genus, and species in the gut microbiota. In conclusion, the beneficial effects of L.p DSM20174 in preventing fatty liver progression may be related to modulations in the composition and potential function of gut microbiota associated with lower metabolic risk factors and a reduced M1-like/M2-like ratio of macrophages and proinflammatory cytokine expression in white adipose tissue and liver.


Subject(s)
Gastrointestinal Microbiome , Non-alcoholic Fatty Liver Disease , Animals , Mice , Non-alcoholic Fatty Liver Disease/etiology , RNA, Ribosomal, 16S/genetics , RNA, Ribosomal, 16S/metabolism , Liver/metabolism , Obesity/metabolism , Inflammation/metabolism , Risk Factors , Diet, High-Fat/adverse effects , Mice, Inbred C57BL
4.
IEEE Trans Pattern Anal Mach Intell ; 44(2): 969-984, 2022 02.
Article in English | MEDLINE | ID: mdl-32870785

ABSTRACT

In this paper, we propose a geometric neural network with edge-aware refinement (GeoNet++) to jointly predict both depth and surface normal maps from a single image. Building on top of two-stream CNNs, GeoNet++ captures the geometric relationships between depth and surface normals with the proposed depth-to-normal and normal-to-depth modules. In particular, the "depth-to-normal" module exploits the least square solution of estimating surface normals from depth to improve their quality, while the "normal-to-depth" module refines the depth map based on the constraints on surface normals through kernel regression. Boundary information is exploited via an edge-aware refinement module. GeoNet++ effectively predicts depth and surface normals with high 3D consistency and sharp boundaries resulting in better reconstructed 3D scenes. Note that GeoNet++ is generic and can be used in other depth/normal prediction frameworks to improve 3D reconstruction quality and pixel-wise accuracy of depth and surface normals. Furthermore, we propose a new 3D geometric metric (3DGM) for evaluating depth prediction in 3D. In contrast to current metrics that focus on evaluating pixel-wise error/accuracy, 3DGM measures whether the predicted depth can reconstruct high quality 3D surface normals. This is a more natural metric for many 3D application domains. Our experiments on NYUD-V2 [1] and KITTI [2] datasets verify that GeoNet++ produces fine boundary details and the predicted depth can be used to reconstruct high quality 3D surfaces.


Subject(s)
Algorithms , Neural Networks, Computer , Least-Squares Analysis
5.
Foods ; 10(7)2021 Jul 08.
Article in English | MEDLINE | ID: mdl-34359462

ABSTRACT

In the last decade, the gastrointestinal microbiota has been recognised as being essential for health. Indeed, several publications have documented the suitability of probiotics, prebiotics, and symbiotics in the management of different diseases such as diabetes mellitus (DM). Advances in laboratory techniques have allowed the identification and characterisation of new biologically active molecules, referred to as "postbiotics". Postbiotics are defined as functional bioactive compounds obtained from food-grade microorganisms that confer health benefits when administered in adequate amounts. They include cell structures, secreted molecules or metabolic by-products, and inanimate microorganisms. This heterogeneous group of molecules presents a broad range of mechanisms and may exhibit some advantages over traditional "biotics" such as probiotics and prebiotics. Owing to the growing incidence of DM worldwide and the implications of the microbiota in the disease progression, postbiotics appear to be good candidates as novel therapeutic targets. In the present review, we summarise the current knowledge about postbiotic compounds and their potential application in diabetes management. Additionally, we envision future perspectives on this topic. In summary, the results indicate that postbiotics hold promise as a potential novel therapeutic strategy for DM.

6.
Hepatology ; 74(5): 2791-2807, 2021 11.
Article in English | MEDLINE | ID: mdl-34170569

ABSTRACT

BACKGROUND AND AIMS: Hepatocellular dedifferentiation is emerging as an important determinant in liver disease progression. Preservation of mature hepatocyte identity relies on a set of key genes, predominantly the transcription factor hepatocyte nuclear factor 4α (HNF4α) but also splicing factors like SLU7. How these factors interact and become dysregulated and the impact of their impairment in driving liver disease are not fully understood. APPROACH AND RESULTS: Expression of SLU7 and that of the adult and oncofetal isoforms of HNF4α, driven by its promoter 1 (P1) and P2, respectively, was studied in diseased human and mouse livers. Hepatic function and damage response were analyzed in wild-type and Slu7-haploinsufficient/heterozygous (Slu7+/- ) mice undergoing chronic (CCl4 ) and acute (acetaminophen) injury. SLU7 expression was restored in CCl4 -injured mice using SLU7-expressing adeno-associated viruses (AAV-SLU7). The hepatocellular SLU7 interactome was characterized by mass spectrometry. Reduced SLU7 expression in human and mouse diseased livers correlated with a switch in HNF4α P1 to P2 usage. This response was reproduced in Slu7+/- mice, which displayed increased sensitivity to chronic and acute liver injury, enhanced oxidative stress, and marked impairment of hepatic functions. AAV-SLU7 infection prevented liver injury and hepatocellular dedifferentiation. Mechanistically we demonstrate a unique role for SLU7 in the preservation of HNF4α1 protein stability through its capacity to protect the liver against oxidative stress. SLU7 is herein identified as a key component of the stress granule proteome, an essential part of the cell's antioxidant machinery. CONCLUSIONS: Our results place SLU7 at the highest level of hepatocellular identity control, identifying SLU7 as a link between stress-protective mechanisms and liver differentiation. These findings emphasize the importance of the preservation of hepatic functions in the protection from liver injury.


Subject(s)
Chemical and Drug Induced Liver Injury/genetics , Hepatocyte Nuclear Factor 4/metabolism , RNA Splicing Factors/metabolism , Acetaminophen/administration & dosage , Acetaminophen/toxicity , Animals , Carbon Tetrachloride/administration & dosage , Carbon Tetrachloride/toxicity , Cell Differentiation/genetics , Cell Line , Chemical and Drug Induced Liver Injury/pathology , Disease Models, Animal , Hepatocyte Nuclear Factor 4/genetics , Hepatocytes/pathology , Humans , Liver/cytology , Liver/drug effects , Liver/pathology , Male , Mice , Oxidative Stress/genetics , Promoter Regions, Genetic , Proteolysis , Transcriptional Activation
7.
Methods ; 187: 3-12, 2021 03.
Article in English | MEDLINE | ID: mdl-32640317

ABSTRACT

Methylation of CpG dinucleotides plays a crucial role in the regulation of gene expression and therefore in the development of different pathologies. Aberrant methylation has been associated to the majority of the diseases, including cancer, neurodegenerative, cardiovascular and autoimmune disorders. Analysis of DNA methylation patterns is crucial to understand the underlying molecular mechanism of these diseases. Moreover, DNA methylation patterns could be used as biomarker for clinical management, such as diagnosis, prognosis and treatment response. Nowadays, a variety of high throughput methods for DNA methylation have been developed to analyze the methylation status of a high number of CpGs at once or even the whole genome. However, identification of specific methylation patterns at specific loci is essential for validation and also as a tool for diagnosis. In this review, we describe the most commonly used approaches to evaluate specific DNA methylation. There are three main groups of techniques that allow the identification of specific regions that are differentially methylated: bisulfite conversion-based methods, restriction enzyme-based approaches, and affinity enrichment-based assays. In the first group, specific restriction enzymes recognize and cleave unmethylated DNA, leaving methylated sequences intact. Bisulfite conversion methods are the most popular approach to distinguish methylated and unmethylated DNA. Unmethylated cytosines are deaminated to uracil by sodium bisulfite treatment, while the methyl cytosines remain unconverted. In the last group, proteins with methylation binding domains or antibodies against methyl cytosines are used to recognize methylated DNA. In this review, we provide the theoretical basis and the framework of each technique as well as the analysis of their strength and the weaknesses.


Subject(s)
DNA Methylation , Epigenesis, Genetic , Epigenomics/methods , Aging/genetics , CpG Islands/genetics , Neoplasms/genetics , Obesity/genetics , Polymerase Chain Reaction/methods , Sequence Analysis, DNA/methods
8.
Nutrients ; 12(9)2020 Aug 19.
Article in English | MEDLINE | ID: mdl-32825073

ABSTRACT

Obesity is a worldwide epidemic characterized by excessive fat accumulation, associated with multiple comorbidities and complications. Emerging evidence points to gut microbiome as a driving force in the pathogenesis of obesity. Vinegar intake, a traditional remedy source of exogenous acetate, has been shown to improve glycemic control and to have anti-obesity effects. New functional foods may be developed by supplementing traditional food with probiotics. B. coagulans is a suitable choice because of its resistance to high temperatures. To analyze the possible synergic effect of Vinegar and B. coagulans against the metabolic alterations induced by a high fat diet (HFD), we fed twelve-week-old C57BL/6 mice with HFD for 5 weeks after 2 weeks of acclimation on a normal diet. Then, food intake, body weight, blood biochemical parameters, histology and liver inflammatory markers were analyzed. Although vinegar drink, either alone or supplemented with B. coagulans, reduced food intake, attenuated body weight gain and enhanced glucose tolerance, only the supplemented drink improved the lipid serum profile and prevented hepatic HFD-induced overexpression of CD36, IL-1ß, IL-6, LXR and SREBP, thus reducing lipid deposition in the liver. The beneficial properties of the B. coagulans-supplemented vinegar appear to be mediated by a reduction in insulin and leptin circulating levels.


Subject(s)
Acetic Acid/administration & dosage , Acetic Acid/pharmacology , Bacillus coagulans , Diet, High-Fat/adverse effects , Dietary Supplements , Fatty Liver/diet therapy , Fatty Liver/etiology , Functional Food , Insulin Resistance , Liver/metabolism , Malus , Obesity/diet therapy , Obesity/etiology , Probiotics/administration & dosage , Probiotics/pharmacology , Weight Gain/drug effects , Animals , Anti-Obesity Agents , Eating/drug effects , Fatty Liver/prevention & control , Gastrointestinal Microbiome , Lipid Metabolism/drug effects , Male , Mice, Inbred C57BL , Obesity/metabolism , Obesity/microbiology
9.
Nucleic Acids Res ; 47(7): 3450-3466, 2019 04 23.
Article in English | MEDLINE | ID: mdl-30657957

ABSTRACT

Genome instability is related to disease development and carcinogenesis. DNA lesions are caused by genotoxic compounds but also by the dysregulation of fundamental processes like transcription, DNA replication and mitosis. Recent evidence indicates that impaired expression of RNA-binding proteins results in mitotic aberrations and the formation of transcription-associated RNA-DNA hybrids (R-loops), events strongly associated with DNA injury. We identify the splicing regulator SLU7 as a key mediator of genome stability. SLU7 knockdown results in R-loops formation, DNA damage, cell-cycle arrest and severe mitotic derangements with loss of sister chromatid cohesion (SCC). We define a molecular pathway through which SLU7 keeps in check the generation of truncated forms of the splicing factor SRSF3 (SRp20) (SRSF3-TR). Behaving as dominant negative, or by gain-of-function, SRSF3-TR impair the correct splicing and expression of the splicing regulator SRSF1 (ASF/SF2) and the crucial SCC protein sororin. This unique function of SLU7 was found in cancer cells of different tissue origin and also in the normal mouse liver, demonstrating a conserved and fundamental role of SLU7 in the preservation of genome integrity. Therefore, the dowregulation of SLU7 and the alterations of this pathway that we observe in the cirrhotic liver could be involved in the process of hepatocarcinogenesis.


Subject(s)
Adaptor Proteins, Signal Transducing/genetics , Carcinogenesis/genetics , Cell Cycle Proteins/genetics , Liver Neoplasms/genetics , RNA Splicing Factors/genetics , Serine-Arginine Splicing Factors/genetics , Alternative Splicing/genetics , Gene Expression Regulation, Neoplastic/genetics , Gene Knockdown Techniques , Genome, Human/genetics , Genomic Instability/genetics , Hep G2 Cells , Humans , RNA Splicing/genetics , Sister Chromatid Exchange/genetics
10.
Hepatology ; 69(2): 587-603, 2019 02.
Article in English | MEDLINE | ID: mdl-30014490

ABSTRACT

Epigenetic modifications such as DNA and histone methylation functionally cooperate in fostering tumor growth, including that of hepatocellular carcinoma (HCC). Pharmacological targeting of these mechanisms may open new therapeutic avenues. We aimed to determine the therapeutic efficacy and potential mechanism of action of our dual G9a histone-methyltransferase and DNA-methyltransferase 1 (DNMT1) inhibitor in human HCC cells and their crosstalk with fibrogenic cells. The expression of G9a and DNMT1, along with that of their molecular adaptor ubiquitin-like with PHD and RING finger domains-1 (UHRF1), was measured in human HCCs (n = 268), peritumoral tissues (n = 154), and HCC cell lines (n = 32). We evaluated the effect of individual and combined inhibition of G9a and DNMT1 on HCC cell growth by pharmacological and genetic approaches. The activity of our lead compound, CM-272, was examined in HCC cells under normoxia and hypoxia, human hepatic stellate cells and LX2 cells, and xenograft tumors formed by HCC or combined HCC+LX2 cells. We found a significant and correlative overexpression of G9a, DNMT1, and UHRF1 in HCCs in association with poor prognosis. Independent G9a and DNMT1 pharmacological targeting synergistically inhibited HCC cell growth. CM-272 potently reduced HCC and LX2 cells proliferation and quelled tumor growth, particularly in HCC+LX2 xenografts. Mechanistically, CM-272 inhibited the metabolic adaptation of HCC cells to hypoxia and induced a differentiated phenotype in HCC and fibrogenic cells. The expression of the metabolic tumor suppressor gene fructose-1,6-bisphosphatase (FBP1), epigenetically repressed in HCC, was restored by CM-272. Conclusion: Combined targeting of G9a/DNMT1 with compounds such as CM-272 is a promising strategy for HCC treatment. Our findings also underscore the potential of differentiation therapy in HCC.


Subject(s)
Antineoplastic Agents/therapeutic use , Carcinoma, Hepatocellular/drug therapy , DNA (Cytosine-5-)-Methyltransferase 1/antagonists & inhibitors , Histone-Lysine N-Methyltransferase/antagonists & inhibitors , Liver Neoplasms, Experimental/drug therapy , Animals , Antineoplastic Agents/pharmacology , CCAAT-Enhancer-Binding Proteins/metabolism , Carcinoma, Hepatocellular/enzymology , DNA (Cytosine-5-)-Methyltransferase 1/metabolism , Dogs , Hep G2 Cells , Histone-Lysine N-Methyltransferase/metabolism , Humans , Liver Neoplasms, Experimental/enzymology , Madin Darby Canine Kidney Cells , Male , Mice, Nude , Ubiquitin-Protein Ligases/metabolism , Xenograft Model Antitumor Assays
11.
Hepatology ; 69(4): 1632-1647, 2019 04.
Article in English | MEDLINE | ID: mdl-30411380

ABSTRACT

Intrahepatic accumulation of bile acids (BAs) causes hepatocellular injury. Upon liver damage, a potent protective response is mounted to restore the organ's function. Epidermal growth factor receptor (EGFR) signaling is essential for regeneration after most types of liver damage, including cholestatic injury. However, EGFR can be activated by a family of growth factors induced during liver injury and regeneration. We evaluated the role of the EGFR ligand, amphiregulin (AREG), during cholestatic liver injury and regulation of AREG expression by BAs. First, we demonstrated increased AREG levels in livers from patients with primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC). In two murine models of cholestatic liver injury, bile duct ligation (BDL) and alpha-naphthyl-isothiocyanate (ANIT) gavage, hepatic AREG expression was markedly up-regulated. Importantly, Areg-/- mice showed aggravated liver injury after BDL and ANIT administration compared to Areg+/+ mice. Recombinant AREG protected from ANIT and BDL-induced liver injury and reduced BA-triggered apoptosis in liver cells. Oral BA administration induced ileal and hepatic Areg expression, and, interestingly, cholestyramine feeding reduced postprandial Areg up-regulation in both tissues. Most interestingly, Areg-/- mice displayed high hepatic cholesterol 7 α-hydroxylase (CYP7A1) expression, reduced serum cholesterol, and high BA levels. Postprandial repression of Cyp7a1 was impaired in Areg-/- mice, and recombinant AREG down-regulated Cyp7a1 mRNA in hepatocytes. On the other hand, BAs promoted AREG gene expression and protein shedding in hepatocytes. This effect was mediated through the farnesoid X receptor (FXR), as demonstrated in Fxr-/- mice, and involved EGFR transactivation. Finally, we show that hepatic EGFR expression is indirectly induced by BA-FXR through activation of suppressor of cytokine signaling-3 (SOC3). Conclusion: AREG-EGFR signaling protects from cholestatic injury and participates in the physiological regulation of BA synthesis.


Subject(s)
Amphiregulin/metabolism , Bile Acids and Salts/biosynthesis , Cholestasis, Intrahepatic/metabolism , Cholesterol 7-alpha-Hydroxylase/metabolism , Animals , ErbB Receptors/metabolism , Humans , Mice, Inbred C57BL
12.
Biochim Biophys Acta Mol Basis Dis ; 1864(4 Pt B): 1326-1334, 2018 04.
Article in English | MEDLINE | ID: mdl-28709961

ABSTRACT

The liver has an extraordinary regenerative capacity rapidly triggered upon injury or resection. This response is intrinsically adjusted in its initiation and termination, a property termed the "hepatostat". Several molecules have been involved in liver regeneration, and among them bile acids may play a central role. Intrahepatic levels of bile acids rapidly increase after resection. Through the activation of farnesoid X receptor (FXR), bile acids regulate their hepatic metabolism and also promote hepatocellular proliferation. FXR is also expressed in enterocytes, where bile acids stimulate the expression of fibroblast growth factor 15/19 (FGF15/19), which is released to the portal blood. Through the activation of FGFR4 on hepatocytes FGF15/19 regulates bile acids synthesis and finely tunes liver regeneration as part of the "hepatostat". Here we review the experimental evidences supporting the relevance of the FXR-FGF15/19-FGFR4 axis in liver regeneration and discuss potential therapeutic applications of FGF15/19 in the prevention of liver failure. This article is part of a Special Issue entitled: Cholangiocytes in Health and Disease edited by Jesus Banales, Marco Marzioni, Nicholas LaRusso and Peter Jansen.


Subject(s)
Bile Acids and Salts/metabolism , Epithelial Cells/metabolism , Fibroblast Growth Factors/metabolism , Liver Failure/prevention & control , Liver Regeneration/drug effects , Animals , Cholagogues and Choleretics/pharmacology , Cholagogues and Choleretics/therapeutic use , Enterocytes/metabolism , Fibroblast Growth Factors/genetics , Fibroblast Growth Factors/pharmacology , Fibroblast Growth Factors/physiology , Fibroblast Growth Factors/therapeutic use , Hepatocytes/metabolism , Humans , Liver/cytology , Liver/metabolism , Liver/pathology , Liver Failure/pathology , Receptor, Fibroblast Growth Factor, Type 4/agonists , Receptor, Fibroblast Growth Factor, Type 4/metabolism , Receptors, Cytoplasmic and Nuclear/agonists , Receptors, Cytoplasmic and Nuclear/metabolism , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Recombinant Proteins/pharmacology , Recombinant Proteins/therapeutic use , Signal Transduction/drug effects , Signal Transduction/physiology
13.
IEEE Trans Pattern Anal Mach Intell ; 40(5): 1259-1272, 2018 05.
Article in English | MEDLINE | ID: mdl-28541196

ABSTRACT

The goal of this paper is to perform 3D object detection in the context of autonomous driving. Our method aims at generating a set of high-quality 3D object proposals by exploiting stereo imagery. We formulate the problem as minimizing an energy function that encodes object size priors, placement of objects on the ground plane as well as several depth informed features that reason about free space, point cloud densities and distance to the ground. We then exploit a CNN on top of these proposals to perform object detection. In particular, we employ a convolutional neural net (CNN) that exploits context and depth information to jointly regress to 3D bounding box coordinates and object pose. Our experiments show significant performance gains over existing RGB and RGB-D object proposal methods on the challenging KITTI benchmark. When combined with the CNN, our approach outperforms all existing results in object detection and orientation estimation tasks for all three KITTI object classes. Furthermore, we experiment also with the setting where LIDAR information is available, and show that using both LIDAR and stereo leads to the best result.

14.
Cell Death Dis ; 8(10): e3083, 2017 10 05.
Article in English | MEDLINE | ID: mdl-28981086

ABSTRACT

The liver displays a remarkable regenerative capacity triggered upon tissue injury or resection. However, liver regeneration can be overwhelmed by excessive parenchymal destruction or diminished by pre-existing conditions hampering repair. Fibroblast growth factor 19 (FGF19, rodent FGF15) is an enterokine that regulates liver bile acid and lipid metabolism, and stimulates hepatocellular protein synthesis and proliferation. FGF19/15 is also important for liver regeneration after partial hepatectomy (PH). Therefore recombinant FGF19 would be an ideal molecule to stimulate liver regeneration, but its applicability may be curtailed by its short half-life. We developed a chimaeric molecule termed Fibapo in which FGF19 is covalently coupled to apolipoprotein A-I. Fibapo retains FGF19 biological activities but has significantly increased half-life and hepatotropism. Here we evaluated the pro-regenerative activity of Fibapo in two clinically relevant models where liver regeneration may be impaired: acetaminophen (APAP) poisoning, and PH in aged mice. The only approved therapy for APAP intoxication is N-acetylcysteine (NAC) and no drugs are available to stimulate liver regeneration. We demonstrate that Fibapo reduced liver injury and boosted regeneration in APAP-intoxicated mice. Fibapo improved survival of APAP-poisoned mice when given at later time points, when NAC is ineffective. Mechanistically, Fibapo accelerated recovery of hepatic glutathione levels, potentiated cell growth-related pathways and increased functional liver mass. When Fibapo was administered to old mice prior to PH, liver regeneration was markedly increased. The exacerbated injury developing in these mice upon PH was attenuated, and the hepatic biosynthetic capacity was enhanced. Fibapo reversed metabolic and molecular alterations that impede regeneration in aged livers. It reduced liver steatosis and downregulated p21 and hepatocyte nuclear factor 4 α (Hnf4α) levels, whereas it stimulated Foxm1b gene expression. Together our findings indicate that FGF19 variants retaining the metabolic and growth-promoting effects of this enterokine may be valuable for the stimulation of liver regeneration.


Subject(s)
Apolipoprotein A-I/genetics , Chemical and Drug Induced Liver Injury/genetics , Fibroblast Growth Factors/genetics , Liver Regeneration/genetics , Acetaminophen/adverse effects , Animals , Apolipoprotein A-I/chemistry , Chemical and Drug Induced Liver Injury/pathology , Fibroblast Growth Factors/chemistry , Gene Expression Regulation , Genetic Engineering , Humans , Lipid Metabolism/genetics , Mice
15.
Dig Dis ; 35(3): 158-165, 2017.
Article in English | MEDLINE | ID: mdl-28249259

ABSTRACT

BACKGROUND: Advanced hepatocellular carcinoma (HCC) is a neoplastic disease with a very bad prognosis and increasing worldwide incidence. HCCs are resistant to conventional chemotherapy and the multikinase inhibitor sorafenib is the only agent that has shown some clinical efficacy. It is therefore important to identify key molecular mechanisms driving hepatocarcinogenesis for the development of more efficacious therapies. However, HCCs are heterogeneous tumors and different molecular subclasses have been characterized. This heterogeneity may underlie the poor performance of most of the targeted therapies so far tested in HCC patients. The fibroblast growth factor 15/19 (FGF15/19), FGF receptor 4 (FGFR4) and beta-Klotho (KLB) correceptor signaling system, a key regulator of bile acids (BA) synthesis and intermediary metabolism, is emerging as an important player in hepatocarcinogenesis. Key Messages: Aberrant signaling through the FGF15/19-FGFR4 pathway participates in the neoplastic behavior of HCC cells, promotes HCC development in mice and its overexpression has been characterized in a subset of HCC tumors from patients with poorer prognosis. Pharmacological interference with FGF15/19-FGFR4 signaling inhibits experimental hepatocarcinogenesis, and specific FGFR4 inhibitors are currently being tested in selected HCC patients with tumoral FGF19-FGFR4/KLB expression. CONCLUSIONS: Interference with FGF19-FGFR4 signaling represents a novel strategy in HCC therapy. Selection of candidate patients based on tumoral FGF19-FGFR4/KLB levels as biomarkers may result in increased efficacy of FGFR4-targeted drugs. Nevertheless, attention should be paid to the potential on target toxic effects of FGFR4 inhibitors due to the key role of this signaling system in BA metabolism.


Subject(s)
Carcinogenesis/metabolism , Fibroblast Growth Factors/metabolism , Liver Neoplasms/metabolism , Animals , Humans , Liver Neoplasms/pathology , Models, Biological , Molecular Targeted Therapy , Signal Transduction/drug effects
16.
Gut ; 66(10): 1818-1828, 2017 10.
Article in English | MEDLINE | ID: mdl-28119353

ABSTRACT

OBJECTIVE: Fibroblast growth factor 15/19 (FGF15/19), an enterokine that regulates synthesis of hepatic bile acids (BA), has been proposed to influence fat metabolism. Without FGF15/19, mouse liver regeneration after partial hepatectomy (PH) is severely impaired. We studied the role of FGF15/19 in response to a high fat diet (HFD) and its regulation by saturated fatty acids. We developed a fusion molecule encompassing FGF19 and apolipoprotein A-I, termed Fibapo, and evaluated its pharmacological properties in fatty liver regeneration. DESIGN: Fgf15-/- mice were fed a HFD. Liver fat and the expression of fat metabolism and endoplasmic reticulum (ER) stress-related genes were measured. Influence of palmitic acid (PA) on FGF15/19 expression was determined in mice and in human liver cell lines. In vivo half-life and biological activity of Fibapo and FGF19 were compared. Hepatoprotective and proregenerative activities of Fibapo were evaluated in obese db/db mice undergoing PH. RESULTS: Hepatosteatosis and ER stress were exacerbated in HFD-fed Fgf15-/- mice. Hepatic expression of Pparγ2 was elevated in Fgf15-/- mice, being reversed by FGF19 treatment. PA induced FGF15/19 expression in mouse ileum and human liver cells, and FGF19 protected from PA-mediated ER stress and cytotoxicity. Fibapo reduced liver BA and lipid accumulation, inhibited ER stress and showed enhanced half-life. Fibapo provided increased db/db mice survival and improved regeneration upon PH. CONCLUSIONS: FGF15/19 is essential for hepatic metabolic adaptation to dietary fat being a physiological regulator of Pparγ2 expression. Perioperative administration of Fibapo improves fatty liver regeneration.


Subject(s)
Endoplasmic Reticulum Stress/drug effects , Fatty Liver/genetics , Fatty Liver/prevention & control , Fibroblast Growth Factors/genetics , Fibroblast Growth Factors/pharmacology , Liver Regeneration/drug effects , Recombinant Fusion Proteins/pharmacology , Animals , Apolipoprotein A-I/genetics , Apolipoprotein A-I/metabolism , Apoptosis/drug effects , Bile Acids and Salts/metabolism , Cell Line , Diet, High-Fat , Endoplasmic Reticulum Stress/genetics , Fatty Liver/metabolism , Fibroblast Growth Factors/metabolism , Half-Life , Hepatectomy , Humans , Ileum/metabolism , Lipid Metabolism/genetics , Liver/metabolism , Liver Regeneration/genetics , Male , Mice , Mice, Obese , PPAR gamma/genetics , PPAR gamma/metabolism , Palmitic Acid/pharmacology , Protein Biosynthesis/drug effects , Recombinant Fusion Proteins/metabolism , Recombinant Fusion Proteins/pharmacokinetics , Up-Regulation
17.
Gut ; 66(6): 1123-1137, 2017 06.
Article in English | MEDLINE | ID: mdl-26818617

ABSTRACT

OBJECTIVE: Liver fibrosis is associated with significant collagen-I deposition largely produced by activated hepatic stellate cells (HSCs); yet, the link between hepatocyte damage and the HSC profibrogenic response remains unclear. Here we show significant induction of osteopontin (OPN) and high-mobility group box-1 (HMGB1) in liver fibrosis. Since OPN was identified as upstream of HMGB1, we hypothesised that OPN could participate in the pathogenesis of liver fibrosis by increasing HMGB1 to upregulate collagen-I expression. DESIGN AND RESULTS: Patients with long-term hepatitis C virus (HCV) progressing in disease stage displayed enhanced hepatic OPN and HMGB1 immunostaining, which correlated with fibrosis stage, whereas it remained similar in non-progressors. Hepatocyte cytoplasmic OPN and HMGB1 expression was significant while loss of nuclear HMGB1 occurred in patients with HCV-induced fibrosis compared with healthy explants. Well-established liver fibrosis along with marked induction of HMGB1 occurred in CCl4-injected OpnHep transgenic yet it was less in wild type and almost absent in Opn-/- mice. Hmgb1 ablation in hepatocytes (Hmgb1ΔHep) protected mice from CCl4-induced liver fibrosis. Coculture with hepatocytes that secrete OPN plus HMGB1 and challenge with recombinant OPN (rOPN) or HMGB1 (rHMGB1) enhanced collagen-I expression in HSCs, which was blunted by neutralising antibodies (Abs) and by Opn or Hmgb1 ablation. rOPN induced acetylation of HMGB1 in HSCs due to increased NADPH oxidase activity and the associated decrease in histone deacetylases 1/2 leading to upregulation of collagen-I. Last, rHMGB1 signalled via receptor for advanced glycation end-products and activated the PI3K-pAkt1/2/3 pathway to upregulate collagen-I. CONCLUSIONS: During liver fibrosis, the increase in OPN induces HMGB1, which acts as a downstream alarmin driving collagen-I synthesis in HSCs.


Subject(s)
Collagen Type I/metabolism , HMGB1 Protein/genetics , HMGB1 Protein/metabolism , Liver Cirrhosis/metabolism , Osteopontin/genetics , Osteopontin/metabolism , Acetylation/drug effects , Animals , Antibodies, Neutralizing , Carbon Tetrachloride , Case-Control Studies , Cell Nucleus/chemistry , Cells, Cultured , Cytoplasm/chemistry , Disease Progression , Gene Expression , HMGB1 Protein/analysis , Hepatic Stellate Cells/metabolism , Hepatitis C, Chronic/complications , Hepatocytes/chemistry , Histone Deacetylase 1/metabolism , Histone Deacetylase 2/metabolism , Humans , Liver Cirrhosis/etiology , Liver Cirrhosis/pathology , Mice , Mice, Knockout , Mice, Transgenic , NADPH Oxidases/metabolism , Osteopontin/analysis , Phosphatidylinositol 3-Kinase/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Receptor for Advanced Glycation End Products/metabolism , Recombinant Proteins/pharmacology , Signal Transduction
18.
IEEE Trans Pattern Anal Mach Intell ; 38(4): 652-65, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26959671

ABSTRACT

Accurate and efficient self-localization is a critical problem for autonomous systems. This paper describes an affordable solution to vehicle self-localization which uses odometry computed from two video cameras and road maps as the sole inputs. The core of the method is a probabilistic model for which an efficient approximate inference algorithm is derived. The inference algorithm is able to utilize distributed computation in order to meet the real-time requirements of autonomous systems in some instances. Because of the probabilistic nature of the model the method is capable of coping with various sources of uncertainty including noise in the visual odometry and inherent ambiguities in the map (e.g., in a Manhattan world). By exploiting freely available, community developed maps and visual odometry measurements, the proposed method is able to localize a vehicle to 4 m on average after 52 seconds of driving on maps which contain more than 2,150 km of drivable roads.

19.
IEEE Trans Pattern Anal Mach Intell ; 38(1): 74-87, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26656579

ABSTRACT

Recent trends in image understanding have pushed for scene understanding models that jointly reason about various tasks such as object detection, scene recognition, shape analysis, contextual reasoning, and local appearance based classifiers. In this work, we are interested in understanding the roles of these different tasks in improved scene understanding, in particular semantic segmentation, object detection and scene recognition. Towards this goal, we "plug-in" human subjects for each of the various components in a conditional random field model. Comparisons among various hybrid human-machine CRFs give us indications of how much "head room" there is to improve scene understanding by focusing research efforts on various individual tasks.


Subject(s)
Artificial Intelligence/statistics & numerical data , Brain-Computer Interfaces/statistics & numerical data , Algorithms , Computer Simulation , Databases, Factual , Humans , Pattern Recognition, Automated/statistics & numerical data , Pattern Recognition, Visual
20.
Hepatology ; 62(1): 166-78, 2015 Jul.
Article in English | MEDLINE | ID: mdl-25808184

ABSTRACT

UNLABELLED: Matrix metalloproteinases (MMPs) participate in tissue repair after acute injury, but also participate in cancer by promoting a protumorigenic microenvironment. Previously, we reported on a key role for MMP10 in mouse liver regeneration. Herein, we investigated MMP10 expression and function in human hepatocellular carcinoma (HCC) and diethylnitrosamine (DEN)-induced mouse hepatocarcinogenesis. MMP10 was induced in human and murine HCC tissues and cells. MMP10-deficient mice showed less HCC incidence, smaller histological lesions, reduced tumor vascularization, and less lung metastases. Importantly, expression of the protumorigenic, C-X-C chemokine receptor-4 (CXCR4), was reduced in DEN-induced MMP10-deficient mice livers. Human HCC cells stably expressing MMP10 had increased CXCR4 expression and migratory capacity. Pharmacological inhibition of CXCR4 significantly reduced MMP10-stimulated HCC cell migration. Furthermore, MMP10 expression in HCC cells was induced by hypoxia and the CXCR4 ligand, stromal-derived factor-1 (SDF1), through the extracellular signal-regulated kinase 1/2 pathway, involving an activator protein 1 site in MMP10 gene promoter. CONCLUSION: MMP10 contributes to HCC development, participating in tumor angiogenesis, growth, and dissemination. We identified a new reciprocal crosstalk between MMP10 and the CXCR4/SDF1 axis contributing to HCC progression and metastasis. To our knowledge, this is the first report addressing the role of a MMP in hepatocarcinogenesis in the corresponding genetic mouse model.


Subject(s)
Chemokine CXCL12/metabolism , Liver Neoplasms, Experimental/etiology , Matrix Metalloproteinase 10/metabolism , Receptors, CXCR4/metabolism , Animals , Cell Line, Tumor , Gene Expression Regulation, Neoplastic , Humans , Hypoxia/metabolism , Liver Neoplasms, Experimental/enzymology , Male , Mice, Inbred C57BL , Receptor Cross-Talk
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