1,721,040 research outputs found
Glycogen content regulates peroxisome proliferator activated receptor-∂ (PPAR-∂) activity in rat skeletal muscle.
Full text linkPerforming exercise in a glycogen depleted state increases skeletal muscle lipid utilization and the transcription of genes regulating mitochondrial β-oxidation. Potential candidates for glycogen-mediated metabolic adaptation are the peroxisome proliferator activated receptor (PPAR) coactivator-1α (PGC-1α) and the transcription factor/nuclear receptor PPAR-∂. It was therefore the aim of the present study to examine whether acute exercise with or without glycogen manipulation affects PGC-1α and PPAR-∂ function in rodent skeletal muscle. Twenty female Wistar rats were randomly assigned to 5 experimental groups (n = 4): control [CON]; normal glycogen control [NG-C]; normal glycogen exercise [NG-E]; low glycogen control [LG-C]; and low glycogen exercise [LG-E]). Gastrocnemius (GTN) muscles were collected immediately following exercise and analyzed for glycogen content, PPAR-∂ activity via chromatin immunoprecipitation (ChIP) assays, AMPK α1/α2 kinase activity, and the localization of AMPK and PGC-1α. Exercise reduced muscle glycogen by 47 and 75% relative to CON in the NG-E and LG-E groups, respectively. Exercise that started with low glycogen (LG-E) finished with higher AMPK-α2 activity (147%, p<0.05), nuclear AMPK-α2 and PGC-1α, but no difference in AMPK-α1 activity compared to CON. In addition, PPAR-∂ binding to the CPT1 promoter was significantly increased only in the LG-E group. Finally, cell reporter studies in contracting C2C12 myotubes indicated that PPAR-∂ activity following contraction is sensitive to glucose availability, providing mechanistic insight into the association between PPAR-∂ and glycogen content/substrate availability. The present study is the first to examine PPAR-∂ activity in skeletal muscle in response to an acute bout of endurance exercise. Our data would suggest that a factor associated with muscle contraction and/or glycogen depletion activates PPAR-∂ and initiates AMPK translocation in skeletal muscle in response to exercise
Neuropathological Responses to Chronic NMDA in Rats Are Worsened by Dietary n-3 PUFA Deprivation but Are Not Ameliorated by Fish Oil Supplementation
Full text linkBackground
Dietary long-chain n-3 polyunsaturated fatty acid (PUFA) supplementation may be beneficial for chronic brain illnesses, but the issue is not agreed on. We examined effects of dietary n-3 PUFA deprivation or supplementation, compared with an n-3 PUFA adequate diet (containing alpha-linolenic acid [18:3 n-3] but not docosahexaenoic acid [DHA, 22:6n-3]), on brain markers of lipid metabolism and excitotoxicity, in rats treated chronically with NMDA or saline. Methods
Male rats after weaning were maintained on one of three diets for 15 weeks. After 12 weeks, each diet group was injected i.p. daily with saline (1 ml/kg) or a subconvulsive dose of NMDA (25 mg/kg) for 3 additional weeks. Then, brain fatty acid concentrations and various markers of excitotoxicity and fatty acid metabolism were measured. Results
Compared to the diet-adequate group, brain DHA concentration was reduced, while n-6 docosapentaenoic acid (DPA, 22:5n-6) concentration was increased in the n-3 deficient group; arachidonic acid (AA, 20:4n-6) concentration was unchanged. These concentrations were unaffected by fish oil supplementation. Chronic NMDA increased brain cPLA2 activity in each of the three groups, but n-3 PUFA deprivation or fish oil did not change cPLA2 activity or protein compared with the adequate group. sPLA2 expression was unchanged in the three conditions, whereas iPLA2 expression was reduced by deprivation but not changed by supplementation. BDNF protein was reduced by NMDA in N-3 PUFA deficient rats, but protein levels of IL-1β, NGF, and GFAP did not differ between groups. Conclusions
N-3 PUFA deprivation significantly worsened several pathological NMDA-induced changes produced in diet adequate rats, whereas n-3 PUFA supplementation did not affect NMDA induced changes. Supplementation may not be critical for this measured neuropathology once the diet has an adequate n-3 PUFA content
Agents and networks to model the dynamic interactions of intracellular transport
Full text linkCell biology is increasingly evolving to become a more formal and quantitative science. The field of intracellular transport is no exception. However, it is extremely challenging to formulate mathematical and computational models for processes that involve dynamic structures that continuously change their shape, position and composition, leading to information transfer and functional outcomes. The two major strategies employed to represent intracellular trafficking are based on ?ordinary differential equations? and ?agent-? based modeling. Both approaches have advantages and drawbacks. Combinations of both modeling strategies have promising characteristics to generate meaningful simulations for intracellular transport and allow the formulation of new hypotheses and provide new insights. In the near future, cell biologists will encounter and hopefully overcome the challenge of translating descriptive cartoon representations of biological systems into mathematical network models.Fil: Mayorga, Luis Segundo. 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: Verma, Meghna. Biocomplexity Institute; Estados UnidosFil: Hontecillas, Raquel. Biocomplexity Institute; Estados UnidosFil: Hoops, Stefan. Biocomplexity Institute; Estados UnidosFil: Bassaganya-Riera, Josep. Biocomplexity Institute; Estados Unido
Abscisic Acid: A Novel Nutraceutical for Glycemic Control
Full text linkAbscisic acid is naturally present in fruits and vegetables, and it plays an important role in managing glucose homeostasis in humans. According to the latest U.S. dietary survey, about 92% of the population might have a deficient intake of ABA due to their deficient intake of fruits and vegetables. This review summarizes the in vitro, preclinical, mechanistic, and human translational findings obtained over the past 15 years in the study of the role of ABA in glycemic control. In 2007, dietary ABA was first reported to ameliorate glucose tolerance and obesity-related inflammation in mice. The most recent findings regarding the topic of ABA and its proposed receptor lanthionine synthetase C-like 2 in glycemic control and their interplay with insulin and glucagon-like peptide-1 suggest a major role for ABA in the physiological response to a glucose load in humans. Moreover, emerging evidence suggests that the ABA response might be dysfunctional in diabetic subjects. Follow on intervention studies in healthy individuals show that low-dose dietary ABA administration exerts a beneficial effect on the glycemia and insulinemia profiles after oral glucose load. These recent findings showing benefits in humans, together with extensive efficacy data in mouse models of diabetes and inflammatory disease, suggest the need for reference ABA values and its possible exploitation of the glycemia-lowering effects of ABA for preventative purposes. Larger clinical studies on healthy, prediabetic, and diabetic subjects are needed to determine whether addressing the widespread dietary ABA deficiency improves glucose control in humans
Dietary conjugated linoleic acid expands CD8+ lymphocyte subsets in vivo and enhances their function
No full textIn the first experiment, 64 pigs were used in a factorial (2 x 4) arrangement within a split-plot design with eight blocks of four littermate pigs as the experimental unit for the environment and pig within litter as the experimental unit for dietary treatment to evaluate the effects of conjugated linoleic acid (CLA) on growth and immune cell phenotype when pigs were located in two distinct health status environments. Diets were formulated to contain CLA at 0, .67, 1.33 or 2% and to exceed NRC (1988) nutrient needs of pigs and were self-fed for 7 wk in three phases. We hypothesized that CLA modifies peripheral lymphocyte phenotype, regardless of the environment. We found that as dietary CLA increases there is a linear increase in percentage of CD8 + peripheral lymphocytes (21.7, 22.3, 28.0, and 32.7%; P < .001). The peripheral CD8+ lymphocyte subpopulation includes four distinct cell subsets: TCRgammadeltaCD8alphaalpha T cells, CD3 --CD8alphaalpha lymphocytes (NK cells) and TCRalphabetaCD8alphabeta T cells, and TCRalphabetaCD4+CD8alphaalpha, and putatively TCRalphabetaCD4 --CD8alphaalpha T cells. To more fully phenotypically characterize the lymphocyte subsets that are most influenced by dietary CLA supplementation and to elucidate the functional implications of their expansion, we conducted the second experiment. A total number of 32 pigs were utilized in a design that from day 0 until the first date of vaccination (d 21) was a randomized complete block with pig within block being the experimental unit for dietary treatment. After d 21, the vaccination treatment was added across blocks and the design became a split-plot; pig within block being the experimental unit for dietary treatment and a block of two littermate pigs being the experimental unit for vaccination treatment. Diets were formulated to contain CLA at 0 or 1.33% and were self-fed for 72 d in four phases. CLA synergized with a Brachyspira hyodysenteriae bacterin vaccine to expand the TCRgammadeltaCD8alphaalpha and NK cell subsets. Dietary CLA alone caused a sustained expansion of TCRalphabetaCD8alphabeta T cells (P < .02) that was related functionally to the increase in granzyme activity in lymphocytes from pigs fed CLA (P < .005) and ontogenically to increased CD8alphabeta+ thymocyte, percentages (P < .05) in pigs fed CLA.</p
Method of preventing and treating inflammatory diseases and disorders with abscisic acid
No full textThe present invention relates to the use of a therapeutically effective amount of abscisic acid (ABA) or its analogs to treat or prevent inflammation induced by exposure to lipopolysaccharide (LPS) or respiratory inflammation. The invention also relates to methods and composition for enhancing vaccine efficacy using ABA
Transdisciplinary Strategies to Study the Mechanisms of CD4+ T cell Differentiation and Heterogeneity
No full textCD4+ T cells mediate and orchestrate a tremendous panoply of lymphoid cell subsets in the human immune system. CD4+ T cells are able to differentiate into either effector pro-inflammatory or regulatory anti-inflammatory subsets depending on the cytokine milieu in their environment. This complex process is mediated through a variety of cytokines and soluble factors. Yet, the mechanisms of action underlying the process of differentiation and plasticity of this interesting immune subset are incompletely understood. To gain a better understanding of the CD4+ T cell differentiation and function, here we present an array of different strategies to model and validate CD4+ T cell differentiation and heterogeneity. The approaches presented here vary from ordinary-differential equation-based to agent-based simulations, from data-driven to theory-based approaches, and from intracellular mathematical to tissue-level or cellular modeling. The knowledge generated throughout this dissertation exemplifies how a combination of computational modeling with experimental immunology can efficiently advance the scene on CD4+ T cell differentiation. In this thesis I present i) an overview on CD4+ T cell differentiation and an introduction to which computational strategies have been adopted in the field to tackle with this problem, ii) ODE-based modeling and predictions on Th17 plasticity modulated by PPARγ, iii) ODE- and ABM-based cellular level modeling of immune responses towards Helicobacter pylori and the role of CD4+ T cell subsets on it, iv) Intracellular strategies to validate a potential therapeutic target within a CD4+ T cell to treat H. pylori infection, and finally v) data-driven strategies to model Th17 differentiation based on sequencing or microarray data to generate novel predictions on specific components. I present both mathematical and computational work as well as experimental work, in vitro and in vivo with animal models, to demonstrate how computational immunology and immunoinformatics can help, not only in understanding this complex process, but also in the development of immune therapeutics for infectious, allergic and immune-mediated diseases.Ph. D
Modeling Host Immune Responses in Infectious Diseases
No full textInfectious diseases caused by bacteria, fungi, viruses and parasites have affected humans historically. Infectious diseases remain a major cause of premature death and a public health concern globally with increased mortality and significant economic burden. Unvaccinated individuals, people with suppressed and compromised immune systems are at higher risk of suffering from infectious diseases. In spite of significant advancements in infectious diseases research, the control or treatment process faces challenges. The mucosal immune system plays a crucial role in safeguarding the body from harmful pathogens, while being constantly exposed to the environment. To develop treatment options for infectious diseases, it is vital to understand the immune responses that occur during infection. The two infectious diseases presented here are: i) Helicobacter pylori infection and ii) human immunodeficiency (HIV) and human papillomavirus (HPV) co-infection. H pylori, is a bacterium that colonizes the stomach and causes gastric cancer in 1-2% but is beneficial for protection against allergies and gastroesophageal diseases. An estimated 85% of H pylori colonized individuals show no detrimental effects. HIV is a virus that causes AIDS, one of the deadliest and most persistent epidemics. HIV-infected patients are at an increased risk of co-infection with HPV, and report an increased incidence of oral cancer. The goal of this thesis is to elucidate the host immune responses in infectious diseases via the use of computational and mathematical models. First, the thesis reviews the need for computational and mathematical models to study the immune responses in the course of infectious diseases. Second, it presents a novel sensitivity analysis method that identifies important parameters in a hybrid (agent-based/equation-based) model of H. pylori infection. Third, it introduces a novel model representing the HIV/HPV coinfection and compares the simulation results with a clinical study. Fourth, it discusses the need of advanced modeling technologies to achieve a personalized systems wide approach and the challenges that can be encountered in the process. Taken together, the work in this dissertation presents modeling approaches that could lead to the identification of host immune factors in infectious diseases in a predictive and more resource-efficient manner.Doctor of PhilosophyInfectious diseases caused by bacteria, fungi, viruses and parasites have affected humans historically. Infectious diseases remain a major cause of premature death and a public health concern globally with increased mortality and significant economic burden. These infections can occur either via air, travel to at-risk places, direct person-to-person contact with an infected individual or through water or fecal route. Unvaccinated individuals, individuals with suppressed and compromised immune system such as that in HIV carriers are at higher risk of getting infectious diseases. In spite of significant advancements in infectious diseases research, the control and treatment of these diseases faces numerous challenges. The mucosal immune system plays a crucial role in safeguarding the body from harmful pathogens, while being exposed to the environment, mainly food antigens. To develop treatment options for infectious diseases, it is vital to understand the immune responses that occur during infection. In this work, we focus on gut immune system that acts like an ecosystem comprising of trillions of interacting cells and molecules, including membars of the microbiome. The goal of this dissertation is to develop computational models that can simulate host immune responses in two infectious diseases- i) Helicobacter pylori infection and ii) human immunodeficiency virus (HIV)-human papilloma virus (HPV) co-infection. Firstly, it reviews the various mathematical techniques and systems biology based methods. Second, it introduces a "hybrid" model that combines different mathematical and statistical approaches to study H. pylori infection. Third, it highlights the development of a novel HIV/HPV coinfection model and compares the results from a clinical trial study. Fourth, it discusses the challenges that can be encountered in adapting machine learning based computational technologies. Taken together, the work in this dissertation presents modeling approaches that could lead to the identification of host immune factors in infectious diseases in a predictive and more resourceful way
Transdisciplinary Strategies for the Characterization of Mucosal Immune Responses to Enteric Pathogens
No full textThe gastrointestinal mucosal immune system has the daunting task of maintaining immune homeostasis by eliminating potentially harmful microorganisms and limiting tissue injury while inducing tolerogenic responses to luminal antigens including innocuous food, commensal bacteria and self-antigens. This carefully orchestrated system depends on elaborate down-regulating mechanisms that mediate and maintain a state of tolerance under normal conditions. Changes in such delicate balance are linked to the development of gastrointestinal pathology as well as systemic disease states. Despite the rapid increase in our appreciation of the gastrointestinal immune system, there is still a major disconnect between the description of how mucosal immune responses are organized and controlled and an insufficient mechanistic understanding of how such responses shape and influence disease outcome and pathogenesis. By using model enteric microorganisms Helicobacter pylori and Clostridium difficile, this dissertation presents a systematic effort to generate novel mechanistic hypothesis based on computational predictions and experimentally elucidate the mechanisms of action underlying mucosal immune responses and pathology in the gut. In this thesis I present i) an overview on mucosal immunology and the need to develop novel therapeutics that limit the pathogenic effects of invading bacteria while maintaining their protective functions, ii) the role of miRNAs in the modulation of immune responses to enteric pathogens, iii) the mechanisms by which Helicobacter pylori is able to limit effector inflammatory responses required for bacterial clearance thus favoring tolerance over immunity, iv) intracellular mechanisms of immune evasion that contribute to bacterial persistence and chronic infection. The knowledge generated throughout this dissertation exemplifies how a combination of computational modeling, immunoinformatics and experimental immunology holds enormous potential for discovering unforeseen targets and developing novel vaccines and cures for infectious, allergic and immune-mediated diseases.Ph. D
Lanthionine synthetase component C-like proteins as molecular targets for preventing and treating diseases and disorders
No full textThe present invention relates to the field of medical treatments for diseases and disorders. More specifically, the present invention relates to the use of the lanthionine synthetase component C-like (LANCL) proteins as therapeutic targets for novel classes of anti-inflammatory, immune regulatory and antidiabetic drugs. This includes but it is not limited to abscisic acid (ABA), ABA analogs, benzimidazophenyls, repurposed drugs or drug combinations, including thiazolidinediones (TZDs); naturally occurring compounds such as conjugated diene fatty acids, conjugated triene fatty acids, isoprenoids, and natural and synthetic agonists of peroxisome proliferator-activated receptors that activate this receptor through an alternative mechanism of action involving LANCL2 or other membrane proteins to treat or prevent the common inflammatory pathogenesis underlying type 2 diabetes, atherosclerosis, cancer, some inflammatory infectious diseases such as influenza and autoimmune diseases including but not limited to inflammatory bowel disease (Crohn's disease and Ulcerative colitis), rheumatoid arthritis, multiple sclerosis and type 1 diabetes and other chronic inflammatory conditions
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