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1.
Cell ; 158(1): 25-40, 2014 Jul 03.
Article in English | MEDLINE | ID: mdl-24995976

ABSTRACT

Obesity and diabetes affect more than half a billion individuals worldwide. Interestingly, the two conditions do not always coincide and the molecular determinants of "healthy" versus "unhealthy" obesity remain ill-defined. Chronic metabolic inflammation (metaflammation) is believed to be pivotal. Here, we tested a hypothesized anti-inflammatory role for heme oxygenase-1 (HO-1) in the development of metabolic disease. Surprisingly, in matched biopsies from "healthy" versus insulin-resistant obese subjects we find HO-1 to be among the strongest positive predictors of metabolic disease in humans. We find that hepatocyte and macrophage conditional HO-1 deletion in mice evokes resistance to diet-induced insulin resistance and inflammation, dramatically reducing secondary disease such as steatosis and liver toxicity. Intriguingly, cellular assays show that HO-1 defines prestimulation thresholds for inflammatory skewing and NF-κB amplification in macrophages and for insulin signaling in hepatocytes. These findings identify HO-1 inhibition as a potential therapeutic strategy for metabolic disease.


Subject(s)
Heme Oxygenase-1/metabolism , Insulin Resistance , Membrane Proteins/metabolism , Obesity/complications , Adipose Tissue/metabolism , Animals , Diet, High-Fat , Hepatocytes/metabolism , Humans , Inflammation/metabolism , Liver/metabolism , Macrophages/metabolism , Metabolic Diseases/metabolism , Metabolic Diseases/physiopathology , Mice , Mice, Knockout , Obesity/physiopathology , Reactive Oxygen Species/metabolism
2.
Cell ; 140(1): 148-60, 2010 Jan 08.
Article in English | MEDLINE | ID: mdl-20074523

ABSTRACT

Over 1 billion people are estimated to be overweight, placing them at risk for diabetes, cardiovascular disease, and cancer. We performed a systems-level genetic dissection of adiposity regulation using genome-wide RNAi screening in adult Drosophila. As a follow-up, the resulting approximately 500 candidate obesity genes were functionally classified using muscle-, oenocyte-, fat-body-, and neuronal-specific knockdown in vivo and revealed hedgehog signaling as the top-scoring fat-body-specific pathway. To extrapolate these findings into mammals, we generated fat-specific hedgehog-activation mutant mice. Intriguingly, these mice displayed near total loss of white, but not brown, fat compartments. Mechanistically, activation of hedgehog signaling irreversibly blocked differentiation of white adipocytes through direct, coordinate modulation of early adipogenic factors. These findings identify a role for hedgehog signaling in white/brown adipocyte determination and link in vivo RNAi-based scanning of the Drosophila genome to regulation of adipocyte cell fate in mammals.


Subject(s)
Drosophila Proteins/metabolism , Hedgehog Proteins/metabolism , Obesity/genetics , Adipocytes, Brown/metabolism , Adipocytes, White/metabolism , Adipogenesis , Animals , Cyclic AMP/metabolism , Glucocorticoids/metabolism , Humans , Mice , Mice, Knockout , Muscle Cells/metabolism , Repressor Proteins/genetics
3.
Proc Natl Acad Sci U S A ; 112(45): E6166-74, 2015 Nov 10.
Article in English | MEDLINE | ID: mdl-26512112

ABSTRACT

Pancreatic acinar cells possess very high protein synthetic rates as they need to produce and secrete large amounts of digestive enzymes. Acinar cell damage and dysfunction cause malnutrition and pancreatitis, and inflammation of the exocrine pancreas that promotes development of pancreatic ductal adenocarcinoma (PDAC), a deadly pancreatic neoplasm. The cellular and molecular mechanisms that maintain acinar cell function and whose dysregulation can lead to tissue damage and chronic pancreatitis are poorly understood. It was suggested that autophagy, the principal cellular degradative pathway, is impaired in pancreatitis, but it is unknown whether impaired autophagy is a cause or a consequence of pancreatitis. To address this question, we generated Atg7(Δpan) mice that lack the essential autophagy-related protein 7 (ATG7) in pancreatic epithelial cells. Atg7(Δpan) mice exhibit severe acinar cell degeneration, leading to pancreatic inflammation and extensive fibrosis. Whereas ATG7 loss leads to the expected decrease in autophagic flux, it also results in endoplasmic reticulum (ER) stress, accumulation of dysfunctional mitochondria, oxidative stress, activation of AMPK, and a marked decrease in protein synthetic capacity that is accompanied by loss of rough ER. Atg7(Δpan) mice also exhibit spontaneous activation of regenerative mechanisms that initiate acinar-to-ductal metaplasia (ADM), a process that replaces damaged acinar cells with duct-like structures.


Subject(s)
Acinar Cells/physiology , Autophagy/physiology , Endoplasmic Reticulum Stress/physiology , Homeostasis/physiology , Microtubule-Associated Proteins/deficiency , Pancreas/cytology , Protein Biosynthesis/physiology , Animals , Autophagy-Related Protein 7 , Fluorescent Antibody Technique , Immunoblotting , Immunohistochemistry , In Situ Nick-End Labeling , Mice , Microscopy, Electron, Transmission
4.
Gut ; 65(10): 1710-20, 2016 10.
Article in English | MEDLINE | ID: mdl-26156960

ABSTRACT

OBJECTIVE: Tumour-associated macrophages (TAMs) play key roles in tumour progression. Recent evidence suggests that TAMs critically modulate the efficacy of anticancer therapies, raising the prospect of their targeting in human cancer. DESIGN: In a large retrospective cohort study involving 110 patients with pancreatic ductal adenocarcinoma (PDAC), we assessed the density of CD68-TAM immune reactive area (%IRA) at the tumour-stroma interface and addressed their prognostic relevance in relation to postsurgical adjuvant chemotherapy (CTX). In vitro, we dissected the synergism of CTX and TAMs. RESULTS: In human PDAC, TAMs predominantly exhibited an immunoregulatory profile, characterised by expression of scavenger receptors (CD206, CD163) and production of interleukin 10 (IL-10). Surprisingly, while the density of TAMs associated to worse prognosis and distant metastasis, CTX restrained their protumour prognostic significance. High density of TAMs at the tumour-stroma interface positively dictated prognostic responsiveness to CTX independently of T-cell density. Accordingly, in vitro, gemcitabine-treated macrophages became tumoricidal, activating a cytotoxic gene expression programme, inhibiting their protumoural effect and switching to an antitumour phenotype. In patients with human PDAC, neoadjuvant CTX was associated to a decreased density of CD206(+) and IL-10(+) TAMs at the tumour-stroma interface. CONCLUSIONS: Overall, our data highlight TAMs as critical determinants of prognostic responsiveness to CTX and provide clinical and in vitro evidence that CTX overall directly re-educates TAMs to restrain tumour progression. These results suggest that the quantification of TAMs could be exploited to select patients more likely to respond to CTX and provide the basis for novel strategies aimed at re-educating macrophages in the context of CTX.


Subject(s)
Antigens, CD/immunology , Antigens, Differentiation, Myelomonocytic/immunology , Carcinoma, Pancreatic Ductal , Chemotherapy, Adjuvant/methods , Macrophages/immunology , Pancreatectomy/methods , Pancreatic Neoplasms , Adult , Antigens, CD/analysis , Antigens, Differentiation, Myelomonocytic/analysis , Carcinoma, Pancreatic Ductal/diagnosis , Carcinoma, Pancreatic Ductal/immunology , Carcinoma, Pancreatic Ductal/pathology , Carcinoma, Pancreatic Ductal/therapy , Female , Humans , Interleukin-10/analysis , Italy , Lectins, C-Type/analysis , Male , Mannose Receptor , Mannose-Binding Lectins/analysis , Neoplasm Metastasis , Neoplasm Staging , Pancreatic Neoplasms/diagnosis , Pancreatic Neoplasms/immunology , Pancreatic Neoplasms/pathology , Pancreatic Neoplasms/therapy , Patient Selection , Prognosis , Receptors, Cell Surface/analysis , Reproducibility of Results , Retrospective Studies , Statistics as Topic , Tumor Microenvironment/drug effects , Tumor Microenvironment/immunology
5.
Anal Chem ; 88(22): 10775-10784, 2016 11 15.
Article in English | MEDLINE | ID: mdl-27732780

ABSTRACT

The cars we drive, the homes we live in, the restaurants we visit, and the laboratories and offices we work in are all a part of the modern human habitat. Remarkably, little is known about the diversity of chemicals present in these environments and to what degree molecules from our bodies influence the built environment that surrounds us and vice versa. We therefore set out to visualize the chemical diversity of five built human habitats together with their occupants, to provide a snapshot of the various molecules to which humans are exposed on a daily basis. The molecular inventory was obtained through untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of samples from each human habitat and from the people that occupy those habitats. Mapping MS-derived data onto 3D models of the environments showed that frequently touched surfaces, such as handles (e.g., door, bicycle), resemble the molecular fingerprint of the human skin more closely than other surfaces that are less frequently in direct contact with humans (e.g., wall, bicycle frame). Approximately 50% of the MS/MS spectra detected were shared between people and the environment. Personal care products, plasticizers, cleaning supplies, food, food additives, and even medications that were found to be a part of the human habitat. The annotations indicate that significant transfer of chemicals takes place between us and our built environment. The workflows applied here will lay the foundation for future studies of molecular distributions in medical, forensic, architectural, space exploration, and environmental applications.


Subject(s)
Ecosystem , Mass Spectrometry , Organic Chemicals/analysis , Organic Chemicals/chemistry , Chromatography, Liquid , Humans , Ions/analysis , Tandem Mass Spectrometry
6.
Eur J Clin Invest ; 46(11): 911-919, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27600500

ABSTRACT

BACKGROUND: Infiltration of white adipose tissue (WAT) by inflammatory cells in obesity is considered to be a key event in the development of insulin resistance. Recently, mast cells (MCs) have been identified as new players in the pathogenesis of obesity. We aimed to investigate the relationship between MCs and various inflammatory markers in serum and WAT and to determine the role of MCs in the aetiology of insulin resistance. MATERIALS AND METHODS: Gene expression was measured in WAT from 20 morbidly obese patients and 20 nonobese control subjects. Homoeostasis Model of Assessment-Insulin Resistance (HOMA-IR) was used to estimate insulin sensitivity. In addition, wild-type and mast cell-deficient mice were fed a high-fat or low-fat diet to study mast cell influence on inflammatory cell polarization in WAT and overall metabolic changes. RESULTS: WAT levels of MC-specific TPSb2 transcript were increased in obesity and significantly positively correlated with TNF, CCL2, CCL5 and CD68 gene expression levels in our study subjects after adjustment for sex, age and BMI. Accordingly, MC deficiency abrogated increase in expression of pro-inflammatory M1 macrophage marker genes in mouse WAT upon high-fat diet feeding. However, MCs accumulated in obese human WAT independent of insulin resistance and systemic changes in inflammatory mediators. CONCLUSIONS: Our results suggest that MCs contribute to the local pro-inflammatory state within WAT in obesity but do not play a primary role in causing insulin resistance.


Subject(s)
Insulin Resistance/physiology , Mast Cells/physiology , Obesity, Morbid/pathology , Adipose Tissue, White/pathology , Adult , Animals , Biomarkers/metabolism , Case-Control Studies , Cells, Cultured , Cytokines/metabolism , Female , Humans , Male , Mice, Inbred C57BL , Phenotype , Thinness/pathology , Tryptases/metabolism
7.
Gastroenterology ; 144(6): 1199-209.e4, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23622129

ABSTRACT

Inflammation and autophagy are cellular defense mechanisms. When these processes are deregulated (deficient or overactivated) they produce pathologic effects, such as oxidative stress, metabolic impairments, and cell death. Unresolved inflammation and disrupted regulation of autophagy are common features of pancreatitis and pancreatic cancer. Furthermore, obesity, a risk factor for pancreatitis and pancreatic cancer, promotes inflammation and inhibits or deregulates autophagy, creating an environment that facilitates the induction and progression of pancreatic diseases. However, little is known about how inflammation, autophagy, and obesity interact to promote exocrine pancreatic disorders. We review the roles of inflammation and autophagy, and their deregulation by obesity, in pancreatic diseases. We discuss the connections among disordered pathways and important areas for future research.


Subject(s)
Autophagy , Inflammation/complications , Obesity/complications , Pancreas/pathology , Pancreatic Neoplasms/etiology , Pancreatitis/etiology , Animals , Humans , Inflammation/immunology , Inflammation/metabolism , Inflammation/pathology , Inflammation Mediators/metabolism , Obesity/immunology , Obesity/metabolism , Obesity/pathology , Pancreas/immunology , Pancreas/metabolism , Pancreatic Neoplasms/immunology , Pancreatic Neoplasms/metabolism , Pancreatic Neoplasms/pathology , Pancreatitis/immunology , Pancreatitis/metabolism , Pancreatitis/pathology , Risk Factors , Signal Transduction
8.
J Comput Chem ; 34(21): 1862-79, 2013 Aug 05.
Article in English | MEDLINE | ID: mdl-23703160

ABSTRACT

Antigen presenting cells present processed peptides via their major histocompatibility (MH) complex to the T cell receptors (TRs) of T cells. If a peptide is immunogenic, a signaling cascade can be triggered within the T cell. However, the binding of different peptides and/or different TRs to MH is also known to influence the spatial arrangement of the MH α-helices which could itself be an additional level of T cell regulation. In this study, we introduce a new methodology based on differential geometric parameters to describe MH deformations in a detailed and comparable way. For this purpose, we represent MH α-helices by curves. On the basis of these curves, we calculate in a first step the curvature and torsion to describe each α-helix independently. In a second step, we calculate the distribution parameter and the conical curvature of the ruled surface to describe the relative orientation of the two α-helices. On the basis of four different test sets, we show how these differential geometric parameters can be used to describe changes in the spatial arrangement of the MH α-helices for different biological challenges. In the first test set, we illustrate on the basis of all available crystal structures for (TR)/pMH complexes how the binding of TRs influences the MH helices. In the second test set, we show a cross evaluation of different MH alleles with the same peptide and the same MH allele with different peptides. In the third test set, we present the spatial effects of different TRs on the same peptide/MH complex. In the fourth test set, we illustrate how a severe conformational change in an α-helix can be described quantitatively. Taken together, we provide a novel structural methodology to numerically describe subtle and severe alterations in MH α-helices for a broad range of applications.


Subject(s)
Major Histocompatibility Complex , Receptors, Antigen, T-Cell/chemistry , Crystallography, X-Ray , Protein Structure, Secondary
9.
Cardiovasc Diabetol ; 12: 138, 2013 Oct 01.
Article in English | MEDLINE | ID: mdl-24083682

ABSTRACT

BACKGROUND: Dyslipidemia, a major risk factor for cardiovascular disease is a common finding in patients with type 2 diabetes and among women with gestational diabetes. Elevated levels of lipoprotein(a) [Lp(a)] are linked to increased risk of cardiovascular disease. However, its relationship with insulin resistance, type 2 diabetes and gestational diabetes is controversial and unproven. Here we aimed to clarify whether Lp(a) levels are associated with insulin sensitivity in pregnancy. METHODS: Sixty-four women with gestational diabetes and 165 with normal glucose tolerance were enrolled in the study. Fasting Lp(a) serum levels were measured in all women at 24-28 weeks of gestation. RESULTS: In pregnancy, there was no significant difference in serum Lp(a) concentrations between the two groups. Its level did not correlate with markers of insulin resistance (HOMA-IR), insulin sensitivity (HOMA-S%), pancreatic beta-cell function (HOMA-B%) and insulin sensitivity in dynamic conditions (OGIS). In addition, fasting glucose and insulin levels and those throughout an oral glucose tolerance test were independent of Lp(a) concentrations in our study group. CONCLUSIONS: Lp(a) levels in pregnant women do not differ with respect to the presence or absence of gestational diabetes. Although influenced by some components of the lipid profile, such as triglycerides and HDL-C, insulin resistance in pregnancy is not affected by Lp(a).


Subject(s)
Diabetes, Gestational/blood , Insulin Resistance , Lipoprotein(a)/blood , Adult , Biomarkers/blood , Blood Glucose/metabolism , Case-Control Studies , Diabetes, Gestational/diagnosis , Female , Gestational Age , Glucose Tolerance Test , Humans , Insulin/blood , Insulin-Secreting Cells/metabolism , Pregnancy
10.
Eur J Clin Invest ; 43(4): 341-9, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23379644

ABSTRACT

BACKGROUND: Pentraxin 3 (PTX3) is a cytokine-inducible molecule expressed in different tissues, the levels of which increase in a response to a variety of inflammatory conditions. Recently, it has been linked to the serum glucose levels and some comorbidities in type 2 diabetes. MATERIALS AND METHODS: Here, we aimed to investigate the role of PTX3 in gestational diabetes mellitus (GDM), which is considered a forerunner of type 2 diabetes. Fasting PTX3 serum levels were measured in 90 women [45 GDM, 45 normal glucose tolerance (NGT)] during pregnancy. In addition, PTX3 was measured during a 2 h, 75 g oral glucose tolerance test (OGTT) in 20 women (10 GDM, 10 NGT) at 24-28 weeks of gestation and in 16 of them after delivery (10GDM, 6 NGT). RESULTS: A continuous increase in PTX3 levels was observed during the OGTT and reached in the GDM group a significant difference after 120 min compared with baseline (P < 0·05). Additionally, a rise in the PTX3 concentration was significantly higher in the GDM- compared with the NGT group, 120 min after glucose challenge (P < 0·01). During pregnancy, serum glucose and C-peptide were positively correlated with the PTX3 levels in the whole study group, whereas a negative association was found with the insulin sensitivity parameters QUICKI and OGIS. CONCLUSIONS: Dependence of PTX3 on serum glucose levels was more pronounced in women with GDM than in the NGT group. This notion together with its inverse relation to the parameters of insulin sensitivity, suggests a potential involvement of PTX3 in GDM pathology.


Subject(s)
C-Reactive Protein/metabolism , Diabetes Mellitus, Type 2/blood , Diabetes, Gestational/blood , Insulin Resistance , Serum Amyloid P-Component/metabolism , Adult , Blood Glucose/metabolism , Diabetes, Gestational/diagnosis , Female , Glucose Tolerance Test , Humans , Insulin/blood , Pregnancy , Regression Analysis
11.
Clin Endocrinol (Oxf) ; 76(4): 499-505, 2012 Apr.
Article in English | MEDLINE | ID: mdl-21958193

ABSTRACT

OBJECTIVE: To evaluate the relationship of plasma fetuin-A levels with markers of bone turnover in male and female type 2 diabetic subjects. BACKGROUND: Fetuin-A, which is a serum protein produced by the liver and promotes bone mineralization, is an independent risk factor for type 2 diabetes, whilst type 2 diabetes is associated with an increased incidence of osteoporosis or fractures. It is not known how fetuin-A levels relate to parameters of bone metabolism in type 2 diabetes. DESIGN AND PATIENTS: Eighty patients with type 2 diabetes [40 men and 40 women matched for age, body mass index (BMI) and time since diagnosis of diabetes] were studied. Fetuin-A together with metabolic parameters and levels of serum carboxy-terminal telopeptide of type 1 collagen (C-telopeptide), osteocalcin, procollagen type 1 amino-terminal propeptide (P1NP), bone alkaline phosphatase (ALP) and sex hormones was determined in all participants. RESULTS: Fetuin-A levels did not differ significantly between male and female diabetic subjects. In a model adjusted for age, BMI, fatty liver index (FLI), time since diagnosis of diabetes, HbA(1c) , antidiabetic and lipid-lowering drug therapies, smoking, total serum protein, creatinine, gamma glutamyl-transferase, parathyroid hormone, C-reactive protein, glomerular filtration rate, and presence of micro-, cardio-, and peripheral vascular diabetic complications, fetuin-A showed a significant positive association with levels of bone ALP (r = 0·71, P = 0·006) in men. In women, fetuin-A was significantly negatively associated with C-telopeptide (r = -0·60, P = 0·03) levels. CONCLUSIONS: Results suggest an independent association of fetuin-A levels with markers of bone turnover in male and female patients with type 2 diabetes. More studies are needed to determine whether fetuin-A could serve as a new marker for fracture risk or osteoporosis in type 2 diabetes and to explore its potential sexually dimorphic effects.


Subject(s)
Diabetes Mellitus, Type 2/blood , alpha-2-HS-Glycoprotein/metabolism , Aged , Alkaline Phosphatase/metabolism , C-Reactive Protein/metabolism , Collagen Type I/blood , Female , Glomerular Filtration Rate/physiology , Humans , Male , Middle Aged , Osteocalcin/blood , Peptides/blood
13.
Cancer Cell ; 39(5): 678-693.e11, 2021 05 10.
Article in English | MEDLINE | ID: mdl-33740421

ABSTRACT

Many cancers, including pancreatic ductal adenocarcinoma (PDAC), depend on autophagy-mediated scavenging and recycling of intracellular macromolecules, suggesting that autophagy blockade should cause tumor starvation and regression. However, until now autophagy-inhibiting monotherapies have not demonstrated potent anti-cancer activity. We now show that autophagy blockade prompts established PDAC to upregulate and utilize an alternative nutrient procurement pathway: macropinocytosis (MP) that allows tumor cells to extract nutrients from extracellular sources and use them for energy generation. The autophagy to MP switch, which may be evolutionarily conserved and not cancer cell restricted, depends on activation of transcription factor NRF2 by the autophagy adaptor p62/SQSTM1. NRF2 activation by oncogenic mutations, hypoxia, and oxidative stress also results in MP upregulation. Inhibition of MP in autophagy-compromised PDAC elicits dramatic metabolic decline and regression of transplanted and autochthonous tumors, suggesting the therapeutic promise of combining autophagy and MP inhibitors in the clinic.


Subject(s)
Autophagy/physiology , Carcinoma, Pancreatic Ductal/metabolism , NF-E2-Related Factor 2/metabolism , Pancreatic Neoplasms/metabolism , Animals , Autophagy/genetics , Carcinoma, Pancreatic Ductal/immunology , Mice , NF-E2-Related Factor 2/pharmacology , Oxidative Stress/drug effects , Oxidative Stress/physiology , Pancreatic Neoplasms/immunology , Pinocytosis/immunology , Pinocytosis/physiology , Sequestosome-1 Protein/metabolism , Signal Transduction/immunology , Signal Transduction/physiology , Pancreatic Neoplasms
14.
Nat Metab ; 2(10): 1034-1045, 2020 10.
Article in English | MEDLINE | ID: mdl-32839596

ABSTRACT

Benign hepatosteatosis, affected by lipid uptake, de novo lipogenesis and fatty acid (FA) oxidation, progresses to non-alcoholic steatohepatitis (NASH) on stress and inflammation. A key macronutrient proposed to increase hepatosteatosis and NASH risk is fructose. Excessive intake of fructose causes intestinal-barrier deterioration and endotoxaemia. However, how fructose triggers these alterations and their roles in hepatosteatosis and NASH pathogenesis remain unknown. Here we show, using mice, that microbiota-derived Toll-like receptor (TLR) agonists promote hepatosteatosis without affecting fructose-1-phosphate (F1P) and cytosolic acetyl-CoA. Activation of mucosal-regenerative gp130 signalling, administration of the YAP-induced matricellular protein CCN1 or expression of the antimicrobial peptide Reg3b (beta) peptide counteract fructose-induced barrier deterioration, which depends on endoplasmic-reticulum stress and subsequent endotoxaemia. Endotoxin engages TLR4 to trigger TNF production by liver macrophages, thereby inducing lipogenic enzymes that convert F1P and acetyl-CoA to FA in both mouse and human hepatocytes.


Subject(s)
Fructose/pharmacology , Inflammation/metabolism , Lipogenesis/drug effects , Acetyl Coenzyme A/pharmacology , Animals , Endotoxemia/blood , Female , Fructosephosphates/pharmacology , Gastrointestinal Microbiome , Hepatocytes/drug effects , Hepatocytes/metabolism , Humans , Intestines/drug effects , Lipidomics , Macrophages/metabolism , Mice , Mice, Inbred C57BL , Non-alcoholic Fatty Liver Disease/metabolism , Regeneration/drug effects , Toll-Like Receptors/agonists
15.
Cancer Cell ; 35(5): 714-720, 2019 05 13.
Article in English | MEDLINE | ID: mdl-31085174

ABSTRACT

Inflammatory cells are important for tumor initiation and promotion, providing cancer cells with cytokines that enhance cell proliferation and survival. Although malignant epithelial cells were traditionally considered to be on the receiving end of these microenvironmental interactions, recent studies show that epithelial cells can undergo inflammatory reprogramming on their own. Such epigenetic switches are often triggered by chronic tissue injury and play important roles in tissue repair. By converting terminally differentiated cells that harbor even a single oncogenic mutation to a less differentiated state with a higher proliferative potential, cell-autonomous inflammation is an important contributor to tumor initiation.


Subject(s)
Inflammation/genetics , Neoplasms/genetics , Animals , Cell Differentiation/genetics , Cell Proliferation/genetics , Epigenesis, Genetic/genetics , Humans , Tumor Microenvironment/genetics
16.
Endocrinology ; 149(3): 1350-7, 2008 Mar.
Article in English | MEDLINE | ID: mdl-18048491

ABSTRACT

Obesity is associated with a chronic low-grade inflammation characterized by macrophage infiltration of adipose tissue (AT) that may underlie the development of insulin resistance and type 2 diabetes. Osteopontin (OPN) is a multifunctional protein involved in various inflammatory processes, cell migration, and tissue remodeling. Because these processes occur in the AT of obese patients, we studied in detail the regulation of OPN expression in human and murine obesity. The study included 20 morbidly obese patients and 20 age- and sex-matched control subjects, as well as two models (diet-induced and genetic) of murine obesity. In high-fat diet-induced and genetically obese mice, OPN expression was drastically up-regulated in AT (40 and 80-fold, respectively) but remained largely unaltered in liver (<2-fold). Moreover, OPN plasma concentrations remained unchanged in both murine models of obesity, suggesting a particular local but not systemic importance for OPN. OPN expression was strongly elevated also in the AT of obese patients compared with lean subjects in both omental and sc AT. In addition, we detected three OPN isoforms to be expressed in human AT and, strikingly, an obesity induced alteration of the OPN isoform expression pattern. Analysis of AT cellular fractions revealed that OPN is exceptionally highly expressed in AT macrophages in humans and mice. Moreover, OPN expression in AT macrophages was strongly up-regulated by obesity. In conclusion, our data point toward a specific local role of OPN in obese AT. Therefore, OPN could be a critical regulator in obesity induced AT inflammation and insulin resistance.


Subject(s)
Adipose Tissue/metabolism , Obesity/metabolism , Osteopontin/metabolism , Adipose Tissue/pathology , Adolescent , Adult , Animals , Case-Control Studies , Disease Models, Animal , Humans , Inflammation , Insulin Resistance , Liver/metabolism , Liver/pathology , Macrophages/metabolism , Macrophages/pathology , Male , Mice , Mice, Inbred C57BL , Middle Aged , Obesity/pathology , Protein Isoforms/metabolism , Subcutaneous Fat/metabolism , Subcutaneous Fat/pathology
17.
J Clin Endocrinol Metab ; 92(11): 4306-12, 2007 Nov.
Article in English | MEDLINE | ID: mdl-17726077

ABSTRACT

CONTEXT: Recent data suggest that circulating retinol-binding protein (RBP) might be involved in the pathogenesis of insulin resistance. Moreover, protein C inhibitor (PCI), which specifically binds retinoic acid, was found to be increased in myocardial infarction survivors who are also insulin resistant. OBJECTIVE: The objective of this study was to investigate the association of insulin resistance with RBP factors and PCI active antigen. DESIGN AND SETTING: This was a clinical study. PATIENTS: Nondiabetic humans with high (IS; n = 20, 14 females, six males, aged 47.2 +/- 1.9 yr, body mass index 26 +/- 1 kg/m(2)) and low (IR; n = 20, 14 females, six males, aged 45.5 +/- 1.7 yr, body mass index 28 +/- 1 kg/m(2)) insulin-stimulated glucose-disposal (M) participated in this study. MAIN OUTCOME MEASURES: M was measured by 2-h hyperinsulinemic (40 mU.min(-1).m(-2))-isoglycemic clamp tests. Measurements of RBP were performed using a nephelometric method and validated using quantitative Western blotting. RESULTS: M (80-120 min) was higher in IS (10.9 +/- 0.6 mg.min(-1).kg(-1)) than IR (4.0 +/- 0.2; P < 10(-12)). Fasting plasma RBP concentrations were comparable between IS and IR measured by both nephelometry (IS: 4.4 +/- 0.3; IR: 4.6 +/- 0.3 mg/dl, P = 0.6) and quantitative Western blot (IS 7.9 +/- 0.5, IR 8.3 +/- 0.6 mg/dl; P = 0.6). Fasting plasma PCI active antigen was similar in both groups. Plasma RBP and PCI were not significantly related to M. RBP was positively correlated with uric acid (r = 0.488, P = 0.003), triglycerides (r = 0.592, P < 0.001), prealbumin (r = 0.63, P < 0.0001), and vitamin A (r = 0.75, P < 10(-6)). CONCLUSIONS: Our data demonstrate that healthy, insulin-resistant humans do not show altered plasma retinol binding factors, such as RBP and PCI. Both do not significantly correlate with insulin sensitivity. Thus, our findings do not support the hypothesis of insulin sensitivity modulation by proteins involved in retinol transport.


Subject(s)
Insulin Resistance/physiology , Protein C Inhibitor/blood , Retinol-Binding Proteins, Plasma/metabolism , Aging/physiology , Blood Glucose/metabolism , Blotting, Western , Body Mass Index , Body Weight/physiology , C-Peptide/blood , Enzyme-Linked Immunosorbent Assay , Fatty Acids, Nonesterified/blood , Female , Gas Chromatography-Mass Spectrometry , Glucose Clamp Technique , Humans , Insulin/blood , Male , Middle Aged , Protein C Inhibitor/immunology , Sex Characteristics , Vitamin A/blood
18.
J Diabetes Res ; 2017: 4108768, 2017.
Article in English | MEDLINE | ID: mdl-28299341

ABSTRACT

Obesity is a major risk factor for several diseases including diabetes, heart disease, and some forms of cancer and due to its rapidly increasing prevalence it has become one of the biggest problems medicine is facing today. All the more surprising, a substantial percentage of obese patients are metabolically healthy when classified based on insulin resistance and systemic inflammation. Oxysterols are naturally occurring molecules that play important role in various metabolic and inflammatory processes and their levels are elevated in patients suffering from obesity and diabetes. 25-Hydroxycholesterol (25-OHC) is produced in cells from cholesterol by the enzyme cholesterol 25-hydroxylase (Ch25h) and is involved in lipid metabolism, inflammatory processes, and cell proliferation. Here, we investigated the role of hepatic Ch25h in the transition from metabolically healthy obesity to insulin resistance and diabetes. Using several different experimental approaches, we demonstrated the significance of Ch25h on the border of "healthy" and "diseased" states of obesity. Adenovirus-mediated Ch25h overexpression in mice improved glucose tolerance and insulin sensitivity and lowered HOMA-IR. Our data suggest that low hepatic Ch25h levels could be considered a risk marker for unhealthy obesity.


Subject(s)
Diabetes Mellitus, Type 2/genetics , Insulin Resistance/genetics , Liver/metabolism , Obesity/genetics , Steroid Hydroxylases/genetics , Animals , Blood Glucose/metabolism , Diabetes Mellitus, Type 2/metabolism , Disease Progression , Male , Mice , Mice, Transgenic , Obesity/metabolism , Steroid Hydroxylases/metabolism
19.
Cancer Cell ; 32(6): 824-839.e8, 2017 Dec 11.
Article in English | MEDLINE | ID: mdl-29153842

ABSTRACT

Despite expression of oncogenic KRAS, premalignant pancreatic intraepithelial neoplasia 1 (PanIN1) lesions rarely become fully malignant pancreatic ductal adenocarcinoma (PDAC). The molecular mechanisms through which established risk factors, such as chronic pancreatitis, acinar cell damage, and/or defective autophagy increase the likelihood of PDAC development are poorly understood. We show that accumulation of the autophagy substrate p62/SQSTM1 in stressed KrasG12D acinar cells is associated with PDAC development and maintenance of malignancy in human cells and mice. p62 accumulation promotes neoplastic progression by controlling the NRF2-mediated induction of MDM2, which acts through p53-dependent and -independent mechanisms to abrogate checkpoints that prevent conversion of differentiated acinar cells to proliferative ductal progenitors. MDM2 targeting may be useful for preventing PDAC development in high-risk individuals.


Subject(s)
Adenocarcinoma in Situ/pathology , Carcinoma, Pancreatic Ductal/pathology , NF-E2-Related Factor 2/metabolism , Pancreatic Neoplasms/pathology , Proto-Oncogene Proteins c-mdm2/metabolism , Acinar Cells/metabolism , Acinar Cells/pathology , Adenocarcinoma in Situ/metabolism , Animals , Carcinoma, Pancreatic Ductal/metabolism , Disease Progression , Heterografts , Humans , Mice , Mice, Inbred C57BL , Mice, Inbred NOD , Mice, SCID , Pancreatic Neoplasms/metabolism , Signal Transduction/physiology
20.
Cancer Prev Res (Phila) ; 9(12): 895-905, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27913448

ABSTRACT

Inflammation is associated with the development and malignant progression of most cancers. As most of the cell types involved in cancer-associated inflammation are genetically stable and thus are not subjected to rapid emergence of drug resistance, the targeting of inflammation represents an attractive strategy both for cancer prevention and for cancer therapy. Tumor-extrinsic inflammation is caused by many factors, including bacterial and viral infections, autoimmune diseases, obesity, tobacco smoking, asbestos exposure, and excessive alcohol consumption, all of which increase cancer risk and stimulate malignant progression. In contrast, cancer-intrinsic or cancer-elicited inflammation can be triggered by cancer-initiating mutations and can contribute to malignant progression through the recruitment and activation of inflammatory cells. Both extrinsic and intrinsic inflammation can result in immunosuppression, thereby providing a preferred background for tumor development. In clinical trials, lifestyle modifications including healthy diet, exercise, alcohol, and smoking cessation have proven effective in ameliorating inflammation and reducing the risk of cancer-related deaths. In addition, consumption of certain anti-inflammatory drugs, including aspirin, can significantly reduce cancer risk, suggesting that common nonsteroidal anti-inflammatory drugs (NSAID) and more specific COX2 inhibitors can be used in cancer prevention. In addition to being examined for their preventative potential, both NSAIDs and more potent anti-inflammatory antibody-based drugs need to be tested for their ability to augment the efficacy of more conventional therapeutic approaches on the basis of tumor resection, radiation, and cytotoxic chemicals. Cancer Prev Res; 9(12); 895-905. ©2016 AACR.


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/therapeutic use , Inflammation/drug therapy , Neoplasms/drug therapy , Neoplasms/prevention & control , Alcoholism/epidemiology , Cytokines/metabolism , Exercise , Humans , Hydroxymethylglutaryl-CoA Reductase Inhibitors/therapeutic use , Inflammation/complications , Microbiota , Neoplasms/etiology , Obesity/epidemiology , Risk Factors , Tobacco Smoking/epidemiology
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