Inflammation, DNA-centered radicals, and oxidative genotoxicity: The role of HOCl produced by myeloperoxidase in carcinogenesis

Myeloid cells (macrophages and neutrophils) infiltrate and synthesize myeloperoxidase (MPO) in sites of inflammation, producing gentotoxicity. In RAW 264.7 macrophages, bacterial lipopolysaccharide (LPS) induces superoxide radical anion, nuclear deformation (nuclear protuberances), MPO synthesis, biomolecule oxidation and cell death. “Freezing” LPS-triggered macrophage activation with the nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) prevented cell activation and death. Oxidation of proteins and genomic DNA was also blocked, with formation of protein- and DNA-DMPO nitrone adducts, as analyzed by immuno-spin trapping with a polyclonal anti-DMPO serum. Interestingly, confocal microscopy analysis of these cells showed that MPO, genomic DNA, and DNA-DMPO nitrone adducts co-localized in the nuclear protuberances. These observations, and the fact that DNA is negatively charged and MPO is a cationic protein, suggest a role for uptaken or newly synthesized MPO in oxidative genotoxicity induced by myeloid cells in sites of inflammation. 
In order to understand MPO-induced formation of DNA-centered radicals, we studied DNA-DMPO nitrone adducts in calf thymus DNA treated with micromolar concentrations of hypochlorous acid (HOCl) added as a bolus or generated in situ by the MPO/H2O2/Cl- system in the presence of DMPO. We also investigated DNA-DMPO nitrone adducts inside living cells containing MPO. The cell models we used were: i) human leukemia (HL)-60 cells, which overexpress MPO, ii) RAW 264.7 macrophages activated with LPS (1 ng/ml for 24 h), to induce MPO, and iii) A549 human airway epithelial cells pre-loaded with human MPO. When these cells were activated with the phorbol ester PMA, the number of 6-thioguanine-resistant cells with the hypoxanthine-guanine phosphoribosyl transferase (HRPT) mutation increased. This mutation was prevented by each of the following: the NADPH oxidase inhibitor apocynin; the MPO inhibitors salicylhydroxamic acid and 4-aminobenzoic acid hydrazide; the cell-permeable HOCl scavenger resveratrol; and DMPO, which traps DNA-centered radicals and prevents further oxidation. 
Genomic DNA-centered radicals and further mutagenesis induced by activated myeloid cells in sites of inflammation can be prevented by blocking MPO activity, preventing formation of and/or scavenging HOCl, or trapping DNA-centered radicals. Our findings provide new therapeutic avenues for preventing carcinogenesis induced by infiltration and activation of myeloid cells in sites of inflammation, for example, in the lung exposed to particulate matter. SUPPORTED BY NIEHS 5R00ES015415-03
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The Nitrone Spin Trap 5,5-Dimethyl-1-pyrroline N-oxide Affects Stress Response and Fate of Lipopolysaccharide-Primed RAW 264.7 Macrophage Cells

The nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) is commonly used to study free radicals. Due to its free radical trapping properties, DMPO is thought to reduce free radial-mediated oxidative damage and other related cellular responses. The purpose of this study was to assess the effect of DMPO on lipopolysaccharide (LPS)-induced inflammation, endoplasmic reticulum (ER) stress, and apoptosis in RAW 264.7 cells. The results showed that DMPO at 50 mM inhibited inducible nitric oxide synthase expression when added shortly after LPS treatment (≤3 h). Interestingly, DMPO increased anti-inflammatory heme oxygenase-1 (HO-1) expression and reversed LPS-induced decrease in HO-1 expression. LPS could increase cellular ER stress as indicated by C/EBP homologous protein (CHOP) induction; DMPO reduced LPS effect on CHOP expression. Unexpectedly, DMPO had a synergistic effect with LPS on increased caspase-3 activity. Overall, DMPO harbors multiple modulating effects but may induce apoptosis in LPS-stressed cells when given at 50 mM, an effective dose for its anti-inflammatory activity in vitro. Our data provide clues for further understanding of the nitrone spin trap with therapeutic potential.Fil: Zhai, Zili. University of Chicago. Department of Medicine. Section of Gastroenterology; Estados UnidosFil: Ramirez, Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas; ArgentinaFil: Gomez-Mejiba, Sandra Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas; Argentin

Molecular mechanisms and therapeutics to reduce adipose tissue inflammation in obesity

La inflamación del tejido adiposo (TA) en obesidad es un proceso central que liga a la obesidad con la inflamación sistémica y el síndrome metabólico. En este proceso los mecanismos de adipogénesis/adiposidad como también la activación inflamatoria de los macrófagos, representan un punto crítico para la búsqueda de nuevas terapéuticas basadas en mecanismos para reducir la inflamación del TA en la obesidad. Basados en nuestros datos clínicos y bioquímicos, discutimos el rol de dos factores de transcripción claves en el proceso de adipogénesis en adipocitos (Nrf-2) y de activación inflamatoria de macrófagos (NF-κB). Se discuten estrategias para la búsqueda de nuevas estructuras químicas que induzcan la activación de la vía del Nrf-2 en adipocitos y reduzcan la activación del NF-κB en los macrófagos usando modelos celulares y moleculares. La elevada incidencia de obesidad y síndrome metabólico a nivel global garantizan la búsqueda de nuevas estructuras químicas de origen natural o sintético para efectivizar la adipogénesis y reducir la inflamación del TA.Adipose tissue (AT) inflammation in obesity is a key process linking obesity, systemic inflammation and metabolic syndrome. The understanding of the molecular mechanisms of adipogenesis/adiposity as well as inflammatory activation of macrophages is critical in the search of novel therapeutics to reduce AT inflammation in obesity. Herein, based on our clinical as well as biochemical data we discuss the role of two transcription factors involved in adipogenesis (Nrf-2) and inflammatory activation of macrophages (NF-κB). We focus our discussion on strategies aimed at screening libraries of natural and synthetic compounds in the search for novel structures able to induce Nrf-2 activation in adipocytes and to reduce NF-κB activation in macrophages by using molecular and cellular models. The growing incidence of metabolic syndrome in obesity justifies the search for novel chemical structures to enhance adipogenesis and to reduce AT inflammation.Fil: Ramirez, Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; ArgentinaFil: Gomez-Mejiba, Sandra Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Ciencias de la Salud; Argentin

The Nitrone Spin Trap 5,5-Dimethyl-1-pyrroline N-oxide prevents M1-like Phenotypic Switch of Lipopolysaccharide-Primed Macrophages

M1-like inflammatory phenotype of macrophages plays a critical role in tissue damage in chronic inflammatory diseases. M1-like macrophages produce reactive oxygen species, inflammatory cytokines (IL-1b, IFNb), express inflammatory protein such as nitric oxide synthase (iNOS) and surface markers such as CD80; CD86; CD14; CD44. Because M1-like activation contributes to inflammation, decoding its mechanism may lead to find novel therapies. The nitrone spin trap DMPO reacts with free radicals to form adducts, thus reducing its chain reactions. Our studies have shown that DMPO has also anti-inflammatory effects that may not be related to its free radical trapping properties. Herein, we hypothesize that DMPO can reduce LPS-induced M1-like activation of macrophages by changing its transcriptome and proteome. To test this hypothesis we incubated RAW 264.7 cells with 1 ng/ml LPS in the presence or absence of 50 mM DMPO for 6h or 24h. Cells were used for the mRNA detection of M1-phenotypic molecular markers. Transcriptomic analyses are consistent with DMPO preventing the inflammatory M1-like of macrophages by reducing surface markers, inflammatory molecules and type-1 interferon signaling. To corroborate these data we used western-blots for IRF7 protein expression and ELISA technique for IFN-b1 determination. DMPO-reduced IFN-b1 production and IRF7 expression, whereas increased hemoxygenase-1 expression and restores PPARδ expression. Taken together our results indicate that DMPO prevents LPS-triggered M1-like phenotypic switch of macrophages. Our studies provide critical data for further studies on the possible use of DMPO as a structural platform for the design of novel mechanism-based anti-inflammatory drugs.Fil: Muñoz, Marcos David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Della Vedova, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Gomez-Mejiba, Sandra Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Ramirez, Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentin

Hypothyroidism modifies lipid composition of polymorphonuclear leukocytes

Thyroid hormones are important regulators of lipid metabolism. Polymorphonuclear leukocytes (PMN) are essential components of innate immune response. Our goal was to determine whether hypothyroidism affects lipid metabolism in PMN cells. Wistar rats were made hypothyroid by administrating 0.1 g/L 6-propyl-2-thiouracil (PTU) in drinking water during 30 days. Triacylglycerides (TG), cholesterol and phospholipids were determined in PMN and serum by conventional methods. The mRNA expression of LDL receptor (LDL-R), 3hydroxy-3-methylglutaryl-CoA reductase (HMGCoAR), sterol regulatory element binding protein 2 (SREBP-2), and diacylglycerol acyltransferase 2 (DGAT-2) were quantified by Real-Time PCR. Cellular neutral lipids were identified by Nile red staining. We found hypothyroidism decreases serum TG whereas it increases them in PMN. This result agrees with those observed in Nile red preparations, however DAGT-2 expression was not modified. Cholesterol synthesizing enzyme HMGCoAR mRNA and protein was reduced in PMN of hypothyroid rats. As expected, cholesterol content decreased in the cells although it increased in serum. Hypothyroidism also reduced relative contents of palmitic, stearic, and arachidonic acids, whereas increased the myristic, linoleic acids, and the unsaturation index in PMN. Thus, hypothyroidism modifies PMN lipid composition. These findings would emphasize the importance of new research to elucidate lipid-induced alterations in specific function(s) of PMN.Fil: Coria, Mariela Janet. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas; ArgentinaFil: Carmona Viglianco, Yamila Virginia. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Marra, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Investigaciones Bioquímicas de La Plata; Argentina; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Médicas; ArgentinaFil: Gomez-Mejiba, Sandra Esther. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Oklahoma Medical Research Foundation; Estados UnidosFil: Ramirez, Dario. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Oklahoma Medical Research Foundation; Estados UnidosFil: Anzulovich Miranda, Ana Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas; ArgentinaFil: Gimenez, Maria Sofia. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentin

The nitrone spin trap 5,5‑dimethyl‑1‑pyrroline N‑oxide binds to toll-like receptor-2-TIR-BB-loop domain and dampens downstream inflammatory signaling

The nitrone spin trap 5,5‑dimethyl‑1‑pyrroline N‑oxide (DMPO) dampens endotoxin-induced and TLR4-driven priming of macrophages, but the mechanism remains unknown. The available information suggests a direct binding of DMPO to the TIR domain, which is shared between TLRs. However, TLR2-TIR domain is the only TLR that have been crystallized. Our in silico data show that DMPO binds to four specific residues in the BB-loop within the TLR2-TIR domain. Our functional analysis using hTLR2.6-expressing HEKs cells showed that DMPO can block zymosan-triggered-TLR2-mediated NF-κB activation. However, DMPO did not affect the overall TLR2-MyD88 protein-protein interaction. DMPO binds to the BB-loop in the TIR-domain and dampens downstream signaling without affecting the overall TIR-MyD88 interaction. These data encourage the use of DMPO-derivatives as potential mechanism-based inhibitors of TLR-triggered inflammation.Fil: Muñoz, Marcos David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Gutierrez, Lucas Joel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Química Básica y Aplicada del Nordeste Argentino. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Instituto de Química Básica y Aplicada del Nordeste Argentino; ArgentinaFil: Delignat, Sandrine. Université Pierre et Marie Curie; Francia. Centre de Recherche des Cordeliers; FranciaFil: Russick, Jules. Université Pierre et Marie Curie; Francia. Centre de Recherche des Cordeliers; FranciaFil: Gomez-Mejiba, Sandra Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Lacroix Desmazes, Sebastien. Centre de Recherche des Cordeliers; Francia. Université Pierre et Marie Curie; FranciaFil: Enriz, Ricardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Ramirez, Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentin

Therapeutic targets to reduce the contribution of pulmonary neutrophilic inflammation towards obesity-associated co-morbidities: a mini-review

Epidemiology and experimental models have shown a close link between adipose tissue inflammation, systemic inflammation and pulmonary neutrophilic inflammation, which predispose obese patients to pulmonary diseases, obesity-associated co-morbidities and cancer. Increased content and activation of neutrophils in the lung microvasculature, resulting from peripheral activation of neutrophils, and increased adhesion of neutrophils to the lung microvasculature are important factors explaining the increased susceptibility of obese patients towards respiratory diseases and loss of insulin sensitivity. Mechanism-based therapies to break this link are urgently needed to reduce pulmonary damage in obesity, due to the growing prevalence of obesity world-wide. Current research suggests that these approaches should be focused on, one or more of the following: reduction of macrophage activation at the adipose tissue, healthy growing of adipose tissue by induction of Nrf-2, inhibition of NF-?B activation, reduction of circulating neutrophil activation, blocking adhesins/selectins, inhibition of neutrophil activation by targeting NADPH oxidase-2 activation, inhibition of myeloperoxidase activity and scavenging of hypochlorous acid. These strategies are expected to reduce adipose tissue inflammation, peripheral inflammation, pulmonary neutrophilic inflammation and obesity-associated co-morbidities.Fil: Claveles Casas, Florencia Nahir. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Barrera, Florencia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: López, Cristofer Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Chacon, Inalen del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Di Sciullo, Maria Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Ramirez, Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Gomez-Mejiba, Sandra Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentin

Hypothyroidism modifies lipid composition of polymorphonuclear leukocytes

Thyroid hormones are important regulators of lipid metabolism. Polymorphonuclear leukocytes (PMN) are essential components of innate immune response. Our goal was to determine whether hypothyroidism affects lipid metabolism in PMN cells. Wistar rats were made hypothyroid by administrating 0.1 g/L 6-propyl-2-thiouracil (PTU) in drinking water during 30 days. Triacylglycerides (TG), cholesterol and phospholipids were determined in PMN and serum by conventional methods. The mRNA expression of LDL receptor (LDL-R), 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCoAR), sterol regulatory element binding protein 2 (SREBP-2), and diacylglycerol acyltransferase 2 (DGAT-2) were quantified by Real-Time PCR. Cellular neutral lipids were identified by Nile red staining. We found hypothyroidism decreases serum TG whereas it increases them in PMN. This result agrees with those observed in Nile red preparations, however DAGT-2 expression was not modified. Cholesterol synthesizing enzyme HMGCoAR mRNA and protein was reduced in PMN of hypothyroid rats. As expected, cholesterol content decreased in the cells although it increased in serum. Hypothyroidism also reduced relative contents of palmitic, stearic, and arachidonic acids, whereas increased the myristic, linoleic acids, and the unsaturation index in PMN. Thus, hypothyroidism modifies PMN lipid composition. These findings would emphasize the importance of new research to elucidate lipid-induced alterations in specific function(s) of PMN.Facultad de Ciencias Médica

A chronic high-fat diet causes sperm head alterations in C57BL/6J mice

A chronic-positive energetic balance has been directly correlated with infertility in men, but the involved mechanisms remain unknown. Herein we investigated weather in a mouse model a chronic feeding with a diet supplemented with chicken fat affects sperm head morphology. To accomplish this, we fed mice for 16 weeks with either control food (low-fat diet, LFD) or control food supplemented with 22% chicken fat (high-fat diet, HFD). At the end of the feeding regimen, we measured: redox and inflammatory changes, cholesterol accumulation in testis and analyzed testicular morphological structure and ultra-structure and liver morphology. We found that the mice fed HFD resembled some features of the human metabolic syndrome, including systemic oxidative stress and inflammation, this group showed an increment in the following parameters; central adiposity (adiposity index: 1.07 0.10 vs 2.26 0.17), dyslipidemia (total cholesterol: 153.3 2.6 vs 175.1 8.08 mg/dL), insulin resistance (indirect Insulin resistance index, TG/HDL-c: 2.94 0.33 vs 3.68 0.15) and fatty liver. Increased cholesterol content measured by filipin was found in the testicles from HFD (fluorescence intensity increase to 50%), as well as an alteration of spermiogenesis. Most remarkably, a disorganized manchette-perinuclear ring complex and an altered morphology of the sperm head were observed in the spermatozoa of HFD-fed mice. These results add new information to our understanding about the mechanisms by which systemic oxidative stress and inflammation may influence sperm-head morphology and indirectly male fertility.Fil: Funes, Abi Karenina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Saez Lancellotti, Tania Emilce Estefania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Santillán, Lucas Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Della Vedova, Maria Cecilia. Universidad Nacional de San Luis; ArgentinaFil: Monclus, Maria de Los Angeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Cabrillana, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Gomez-Mejiba, Sandra Esther. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; ArgentinaFil: Ramirez, D. C.. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; ArgentinaFil: Fornes, Miguel Walter. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentin

Comment on: Kim et al. Deficiency for costimulatory receptor 4-1BB protects against obesity-induced inflammation and metabolic disorders. Diabetes 2011;60:3159-3168

In the December 2011 issue of Diabetes, Kim et al. [1] reported that 4-1BB (CD137/TNFRSF9) deficiency protected against high fat diet (HFD)-induced obesity, glucose intolerance and fatty liver disease. They found that 4-1BB deficiency reduced number and activation of macrophages/CD8+ T cells/Th1 cells into adipose tissue, reduced circulating pro-inflammatory cytokines, and improved insulin sensitivity/liver pathology with respect to wild-type animals fed the same diet. This is an important advance in the field because antagonism of the 4-1BB/4-1BB ligand interaction (e.g., modulating its expression, blocking receptor/ligand interaction and interfering signaling) could help reduce macrophage infiltration and adipose tissue inflammation in obesity. However, in a paper published by the same laboratories in 2010 in Endocrinology [2] they found that 4-1BB stimulation with an agonistic antibody reduced weight gain and adiposity, increased energy expenditure and improved insulin tolerance and fatty liver disease in HFD-fed mice and genetically obese mice. The authors suggest that these effects would have been caused by 4-1BB induced expansion/activation of CD8+ T-cells and consequent increased energy expenditure. We are puzzled to understand this apparent discrepancy between these two elegant studies [1, 2] and why the first study was not discussed in the Diabetes paper, which would help us understand the rationale of these apparently opposite results between these studies.   Inflammation and dysfunction of adipose tissue have emerged as important targets to reduce systemic inflammation and insulin resistance (IR) associated to obesity [3]. As supported by an extensive body of evidence, most of the inflammatory cytokines produced by inflamed adipose tissue derives from fat-infiltrating and classically-activated M1 macrophages [3]. This infiltration and activation of macrophages into the stressed adipose tissue in obesity play critical roles in metabolic alterations associated to obesity [3]. Nishimura’s work [4] has highlighted the importance of CD8+ T-cells in monocyte infiltration, and differentiation and survival as macrophages into the obese adipose tissue [4]. Moreover, 4-1BB expression increases upon activation in T-cells and in inflamed vessel walls, where it promotes monocyte migration and macrophage differentiation, survival and activation [5]. This agrees with Kim’s data regarding increased expression of 4-1BB in adipose tissue of obese wild type mice [1]. Therefore and opposite to what reported in [2], we would have expected that administration of an antibody that agonizes 4-1BB signaling in obese wild-type mice would increase activation of CD8+ cells and promote more macrophage infiltration and activation into the fat tissue. To facilitate the advancement in the field it is necessary to have a clearer picture of how agonists or antagonists of 4-1BB and/or 4-1BB ligand change macrophage recruitment and activation in the metabolically-stressed adipose tissue in obesity. Understanding of these processes will ensure mechanism-based interventions to reduce macrophage infiltration and consequent adipose tissue inflammation—a leading cause of metabolic complications of obesity.Fil: Gomez-Mejiba, Sandra Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Ramirez, Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentin