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Lagou MK, Karagiannis GS. Obesity-induced thymic involution and cancer risk. Semin Cancer Biol 2023; 93:3-19. [PMID: 37088128 DOI: 10.1016/j.semcancer.2023.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 04/25/2023]
Abstract
Declining thymic functions associated either with old age (i.e., age-related thymic involution), or with acute involution as a result of stress, infectious disease, or cytoreductive therapies (e.g., chemotherapy/radiotherapy), have been associated with cancer development. A key mechanism underlying such increased cancer risk is the thymus-dependent debilitation of adaptive immunity, which is responsible for orchestrating immunoediting mechanisms and tumor immune surveillance. In the past few years, a blooming set of evidence has intriguingly linked obesity with cancer development and progression. The majority of such studies has focused on obesity-driven chronic inflammation, steroid/sex hormone and adipokine production, and hyperinsulinemia, as principal factors affecting the tumor microenvironment and driving the development of primary malignancy. However, experimental observations about the negative impact of obesity on T cell development and maturation have existed for more than half a century. Here, we critically discuss the molecular and cellular mechanisms of obesity-driven thymic involution as a previously underrepresented intermediary pathology leading to cancer development and progression. This knowledge could be especially relevant in the context of childhood obesity, because impaired thymic function in young individuals leads to immune system abnormalities, and predisposes to various pediatric cancers. A thorough understanding behind the molecular and cellular circuitries governing obesity-induced thymic involution could therefore help towards the rationalized development of targeted thymic regeneration strategies for obese individuals at high risk of cancer development.
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Affiliation(s)
- Maria K Lagou
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA; Tumor Microenvironment of Metastasis Program, Albert Einstein Cancer Center, Bronx, NY, USA
| | - George S Karagiannis
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA; Tumor Microenvironment of Metastasis Program, Albert Einstein Cancer Center, Bronx, NY, USA; Cancer Dormancy and Tumor Microenvironment Institute, Albert Einstein College of Medicine, Bronx, NY, USA; Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, USA; Integrated Imaging Program for Cancer Research, Albert Einstein College of Medicine, Bronx, NY, USA.
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2
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Orlova E, Loginova O, Shirshev S. Leptin regulates thymic plasmacytoid dendritic cell ability to influence the thymocyte distribution in vitro. Int Immunopharmacol 2023; 117:109912. [PMID: 36857934 DOI: 10.1016/j.intimp.2023.109912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 02/07/2023] [Accepted: 02/14/2023] [Indexed: 03/03/2023]
Abstract
Leptin, the adipocyte-derived hormone, involved in regulating food intake and body weight, plays an important role in immunity and reproduction. Leptin signals via the specific membrane receptors expressed in most types of immune cells including dendritic cells (DCs) and thymocytes. Leptin enhances thymopoiesis and modulates T-cell-mediated immunity. Thymic plasmacytoid DCs (pDCs) are predominated in the thymus. They play an important role in thymocyte differentiation. We have analyzed whether leptin mediates its effects on human thymocytes by influencing on pDCs. We used leptin at concentration corresponding to its level during II-III trimesters of physiological pregnancy. We cultivated leptin-primed pDCs with autologous thymocytes and estimated the main thymocyte subsets expressing αβ chains of the T-cell receptor (αβTCR), natural regulatory T-cells (tTreg), natural T-helpers producing interleukin-17 (nTh17) and invariant natural killer T-cells (iNKT) in vitro. We have shown that leptin augmented CD86, CD276 expressions and depressed IL-10 productions by pDCs. Leptin-primed pDCs decreased the percentage of CD4+CD8+αβTCR+ thymocytes, increased CD4hiCD8-/loαβTCR+ cells. pDCs cultivated with leptin decreased the number of iNKT precursors, and did not change the number of tTreg and nTh17 precursors. Thus, leptin's important role in regulation of thymic pDC abilities to influence on the thymocyte distribution was indicated in vitro.
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Affiliation(s)
- Ekaterina Orlova
- Laboratory of Immunoregulation, Perm Federal Research Center, Ural Branch of the Russian Academy of Sciences, 13A Lenina str., 614015 Perm, Russia.
| | - Olga Loginova
- Laboratory of Immunoregulation, Perm Federal Research Center, Ural Branch of the Russian Academy of Sciences, 13A Lenina str., 614015 Perm, Russia.
| | - Sergei Shirshev
- Laboratory of Immunoregulation, Perm Federal Research Center, Ural Branch of the Russian Academy of Sciences, 13A Lenina str., 614015 Perm, Russia.
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3
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Savino W, Durães J, Maldonado-Galdeano C, Perdigon G, Mendes-da-Cruz DA, Cuervo P. Thymus, undernutrition, and infection: Approaching cellular and molecular interactions. Front Nutr 2022; 9:948488. [PMID: 36225882 PMCID: PMC9549110 DOI: 10.3389/fnut.2022.948488] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 09/05/2022] [Indexed: 11/29/2022] Open
Abstract
Undernutrition remains a major issue in global health. Low protein-energy consumption, results in stunting, wasting and/or underweight, three deleterious forms of malnutrition that affect roughly 200 million children under the age of five years. Undernutrition compromises the immune system with the generation of various degrees of immunodeficiency, which in turn, renders undernourished individuals more sensitive to acute infections. The severity of various infectious diseases including visceral leishmaniasis (VL), influenza, and tuberculosis is associated with undernutrition. Immunosuppression resulting from protein-energy undernutrition severely impacts primary and secondary lymphoid organs involved in the response to related pathogens. The thymus-a primary lymphoid organ responsible for the generation of T lymphocytes-is particularly compromised by both undernutrition and infectious diseases. In this respect, we will discuss herein various intrathymic cellular and molecular interactions seen in undernutrition alone or in combination with acute infections. Many examples illustrated in studies on humans and experimental animals clearly revealed that protein-related undernutrition causes thymic atrophy, with cortical thymocyte depletion. Moreover, the non-lymphoid microenvironmental compartment of the organ undergoes important changes in thymic epithelial cells, including their secretory products such as hormones and extracellular matrix proteins. Of note, deficiencies in vitamins and trace elements also induce thymic atrophy. Interestingly, among the molecular interactions involved in the control of undernutrition-induced thymic atrophy is a hormonal imbalance with a rise in glucocorticoids and a decrease in leptin serum levels. Undernutrition also yields a negative impact of acute infections upon the thymus, frequently with the intrathymic detection of pathogens or their antigens. For instance, undernourished mice infected with Leishmania infantum (that causes VL) undergo drastic thymic atrophy, with significant reduction in thymocyte numbers, and decreased levels of intrathymic chemokines and cytokines, indicating that both lymphoid and microenvironmental compartments of the organ are affected. Lastly, recent data revealed that some probiotic bacteria or probiotic fermented milks improve the thymus status in a model of malnutrition, thus raising a new field for investigation, namely the thymus-gut connection, indicating that probiotics can be envisioned as a further adjuvant therapy in the control of thymic changes in undernutrition accompanied or not by infection.
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Affiliation(s)
- Wilson Savino
- Laboratory on Thymus Research, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
- Brazilian National Institute of Science and Technology on Neuroimmunomodulation, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
- Rio de Janeiro Research Network on Neuroinflammation, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Jonathan Durães
- Rio de Janeiro Research Network on Neuroinflammation, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
- Laboratory on Leishmaniasis Research, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Carolina Maldonado-Galdeano
- Laboratory of Immunology, Reference Center for Lactobacilli Centro de Referencia para Lactobacilos-Consejo Nacional de Investigaciones Científicas y Técnicas (CERELA-CONICET), San Miguel de Tucumán, Argentina
- Laboratory of Immunology, Faculty of Biochemistry, Chemistry and Pharmacy, National University of Tucumán, San Miguel de Tucumán, Argentina
| | - Gabriela Perdigon
- Laboratory of Immunology, Reference Center for Lactobacilli Centro de Referencia para Lactobacilos-Consejo Nacional de Investigaciones Científicas y Técnicas (CERELA-CONICET), San Miguel de Tucumán, Argentina
- Laboratory of Immunology, Faculty of Biochemistry, Chemistry and Pharmacy, National University of Tucumán, San Miguel de Tucumán, Argentina
| | - Daniella Arêas Mendes-da-Cruz
- Laboratory on Thymus Research, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
- Brazilian National Institute of Science and Technology on Neuroimmunomodulation, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
- Rio de Janeiro Research Network on Neuroinflammation, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
- School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston, United Kingdom
| | - Patricia Cuervo
- Rio de Janeiro Research Network on Neuroinflammation, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
- Laboratory on Leishmaniasis Research, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
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Balcells F, Martínez Monteros MJ, Gómez AL, Cazorla SI, Perdigón G, Maldonado-Galdeano C. Probiotic Consumption Boosts Thymus in Obesity and Senescence Mouse Models. Nutrients 2022; 14:nu14030616. [PMID: 35276973 PMCID: PMC8838891 DOI: 10.3390/nu14030616] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 01/21/2022] [Accepted: 01/23/2022] [Indexed: 02/01/2023] Open
Abstract
The ability of the immune system to respond to different pathogens throughout life requires the constant production and selection of T cells in the thymus. This immune organ is very sensitive to age, infectious processes and nutrition disorders (obesity and malnutrition). Several studies have shown that the incorporation of some probiotic bacteria or probiotic fermented milk in the diet has beneficial effects, not only at the intestinal level but also on distant mucosal tissues, improving the architecture of the thymus in a malnutrition model. The aim of the present study was to determine whether supplementation with the probiotic strain Lactobacillus casei CRL 431 and/or its cell wall could improve body weight, intestinal microbiota and thymus structure and function in both obese and aging mice. We evaluated probiotic administration to BALB/c mice in 2 experimental mouse models: obesity and senescence, including mice of different ages (21, 28, 45, 90 and 180 days). Changes in thymus size and histology were recorded. T-lymphocyte population and cytokine production were also determined. The consumption of probiotics improved the cortical/medullary ratio, the production and regulation of cytokines and the recovery of mature T-lymphocyte populations of the thymus in obese and old mice. Probiotic incorporation into the diet could not only modulate the immune system but also lead to thymus function recovery, thus improving quality of life.
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Affiliation(s)
- Florencia Balcells
- Laboratorio de Inmunología, Centro de Referencia para Lactobacilos (CERELA-CONICET), San Miguel de Tucumán 4000, Argentina; (F.B.); (M.J.M.M.); (S.I.C.); (G.P.)
| | - María José Martínez Monteros
- Laboratorio de Inmunología, Centro de Referencia para Lactobacilos (CERELA-CONICET), San Miguel de Tucumán 4000, Argentina; (F.B.); (M.J.M.M.); (S.I.C.); (G.P.)
| | - Alba Lorena Gómez
- PatLab Laboratorio de Anatomía Patológica Citopatología e Inmunohistoquímica, San Miguel de Tucumán 4000, Argentina;
| | - Silvia Inés Cazorla
- Laboratorio de Inmunología, Centro de Referencia para Lactobacilos (CERELA-CONICET), San Miguel de Tucumán 4000, Argentina; (F.B.); (M.J.M.M.); (S.I.C.); (G.P.)
- Cátedra de Inmunología, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, San Miguel de Tucumán 4000, Argentina
| | - Gabriela Perdigón
- Laboratorio de Inmunología, Centro de Referencia para Lactobacilos (CERELA-CONICET), San Miguel de Tucumán 4000, Argentina; (F.B.); (M.J.M.M.); (S.I.C.); (G.P.)
| | - Carolina Maldonado-Galdeano
- Laboratorio de Inmunología, Centro de Referencia para Lactobacilos (CERELA-CONICET), San Miguel de Tucumán 4000, Argentina; (F.B.); (M.J.M.M.); (S.I.C.); (G.P.)
- Cátedra de Inmunología, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, San Miguel de Tucumán 4000, Argentina
- Correspondence:
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SantaCruz-Calvo S, Bharath L, Pugh G, SantaCruz-Calvo L, Lenin RR, Lutshumba J, Liu R, Bachstetter AD, Zhu B, Nikolajczyk BS. Adaptive immune cells shape obesity-associated type 2 diabetes mellitus and less prominent comorbidities. Nat Rev Endocrinol 2022; 18:23-42. [PMID: 34703027 PMCID: PMC11005058 DOI: 10.1038/s41574-021-00575-1] [Citation(s) in RCA: 59] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/17/2021] [Indexed: 02/07/2023]
Abstract
Obesity and type 2 diabetes mellitus (T2DM) are increasing in prevalence owing to decreases in physical activity levels and a shift to diets that include addictive and/or high-calorie foods. These changes are associated with the adoption of modern lifestyles and the presence of an obesogenic environment, which have resulted in alterations to metabolism, adaptive immunity and endocrine regulation. The size and quality of adipose tissue depots in obesity, including the adipose tissue immune compartment, are critical determinants of overall health. In obesity, chronic low-grade inflammation can occur in adipose tissue that can progress to systemic inflammation; this inflammation contributes to the development of insulin resistance, T2DM and other comorbidities. An improved understanding of adaptive immune cell dysregulation that occurs during obesity and its associated metabolic comorbidities, with an appreciation of sex differences, will be critical for repurposing or developing immunomodulatory therapies to treat obesity and/or T2DM-associated inflammation. This Review critically discusses how activation and metabolic reprogramming of lymphocytes, that is, T cells and B cells, triggers the onset, development and progression of obesity and T2DM. We also consider the role of immunity in under-appreciated comorbidities of obesity and/or T2DM, such as oral cavity inflammation, neuroinflammation in Alzheimer disease and gut microbiome dysbiosis. Finally, we discuss previous clinical trials of anti-inflammatory medications in T2DM and consider the path forward.
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Affiliation(s)
- Sara SantaCruz-Calvo
- Department of Pharmacology and Nutritional Sciences and the Barnstable Brown Diabetes and Obesity Center, University of Kentucky, Lexington, KY, USA.
| | - Leena Bharath
- Department of Nutrition and Public Health, Merrimack College, North Andover, MA, USA
| | - Gabriella Pugh
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, KY, USA
| | - Lucia SantaCruz-Calvo
- Department of Chemistry and Food Technology, Technical University of Madrid, Madrid, Spain
| | - Raji Rajesh Lenin
- Department of Pharmacology and Nutritional Sciences and the Barnstable Brown Diabetes and Obesity Center, University of Kentucky, Lexington, KY, USA
| | - Jenny Lutshumba
- Department of Neuroscience, University of Kentucky, Lexington, KY, USA
| | - Rui Liu
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY, USA
| | | | - Beibei Zhu
- Department of Pharmacology and Nutritional Sciences and the Barnstable Brown Diabetes and Obesity Center, University of Kentucky, Lexington, KY, USA
| | - Barbara S Nikolajczyk
- Department of Pharmacology and Nutritional Sciences and the Barnstable Brown Diabetes and Obesity Center, University of Kentucky, Lexington, KY, USA.
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6
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Guglielmi V, Colangeli L, D’Adamo M, Sbraccia P. Susceptibility and Severity of Viral Infections in Obesity: Lessons from Influenza to COVID-19. Does Leptin Play a Role? Int J Mol Sci 2021; 22:ijms22063183. [PMID: 33804765 PMCID: PMC8003928 DOI: 10.3390/ijms22063183] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/05/2021] [Accepted: 03/18/2021] [Indexed: 12/13/2022] Open
Abstract
The recent pandemic Sars-CoV2 infection and studies on previous influenza epidemic have drawn attention to the association between the obesity and infectious diseases susceptibility and worse outcome. Metabolic complications, nutritional aspects, physical inactivity, and a chronic unbalance in the hormonal and adipocytokine microenvironment are major determinants in the severity of viral infections in obesity. By these pleiotropic mechanisms obesity impairs immune surveillance and the higher leptin concentrations produced by adipose tissue and that characterize obesity substantially contribute to such immune response dysregulation. Indeed, leptin not only controls energy balance and body weight, but also plays a regulatory role in the interplay between energy metabolism and immune system. Since leptin receptor is expressed throughout the immune system, leptin may exert effects on cells of both innate and adaptive immune system. Chronic inflammatory states due to metabolic (i.e., obesity) as well as infectious diseases increase leptin concentrations and consequently lead to leptin resistance further fueling inflammation. Multiple factors, including inflammation and ER stress, contribute to leptin resistance. Thus, if leptin is recognized as one of the adipokines responsible for the low grade inflammation found in obesity, on the other hand, impairments of leptin signaling due to leptin resistance appear to blunt the immunologic effects of leptin and possibly contribute to impaired vaccine-induced immune responses. However, many aspects concerning leptin interactions with inflammation and immune system as well as the therapeutical approaches to overcome leptin resistance and reduced vaccine effectiveness in obesity remain a challenge for future research.
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7
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Immune-neuroendocrine and metabolic disorders in human and experimental T. cruzi infection: New clues for understanding Chagas disease pathology. Biochim Biophys Acta Mol Basis Dis 2019; 1866:165642. [PMID: 31866417 DOI: 10.1016/j.bbadis.2019.165642] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 12/13/2019] [Indexed: 12/12/2022]
Abstract
Studies in mice undergoing acute Trypanosoma cruzi infection and patients with Chagas disease, led to identify several immune-neuroendocrine disturbances and metabolic disorders. Here, we review relevant findings concerning such abnormalities and discuss their possible influence on disease physiopathology.
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8
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Park C, Cheung KP, Limon N, Costanzo A, Barba C, Miranda N, Gargas S, Johnson AMF, Olefsky JM, Jameson JM. Obesity Modulates Intestinal Intraepithelial T Cell Persistence, CD103 and CCR9 Expression, and Outcome in Dextran Sulfate Sodium–Induced Colitis. THE JOURNAL OF IMMUNOLOGY 2019; 203:3427-3435. [DOI: 10.4049/jimmunol.1900082] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 10/17/2019] [Indexed: 12/18/2022]
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9
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Fang P, Li X, Shan H, Saredy JJ, Cueto R, Xia J, Jiang X, Yang XF, Wang H. Ly6C + Inflammatory Monocyte Differentiation Partially Mediates Hyperhomocysteinemia-Induced Vascular Dysfunction in Type 2 Diabetic db/db Mice. Arterioscler Thromb Vasc Biol 2019; 39:2097-2119. [PMID: 31366217 PMCID: PMC6761027 DOI: 10.1161/atvbaha.119.313138] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Hyperhomocysteinemia (HHcy) is a potent risk factor for diabetic cardiovascular diseases. We have previously reported that hyperhomocysteinemia potentiates type 1 diabetes mellitus-induced inflammatory monocyte differentiation, vascular dysfunction, and atherosclerosis. However, the effects of hyperhomocysteinemia on vascular inflammation in type 2 diabetes mellitus (T2DM) and the underlying mechanism are unknown. Approach and Results: Here, we demonstrate that hyperhomocysteinemia was induced by a high methionine diet in control mice (homocysteine 129 µmol/L), which was further worsened in T2DM db/db mice (homocysteine 180 µmol/L) with aggravated insulin intolerance. Hyperhomocysteinemia potentiated T2DM-induced mononuclear cell, monocyte, inflammatory monocyte (CD11b+Ly6C+), and M1 macrophage differentiation in periphery and aorta, which were rescued by folic acid-based homocysteine-lowering therapy. Moreover, hyperhomocysteinemia exacerbated T2DM-impaired endothelial-dependent aortic relaxation to acetylcholine. Finally, transfusion of bone marrow cells depleted for Ly6C by Ly6c shRNA transduction improved insulin intolerance and endothelial-dependent aortic relaxation in hyperhomocysteinemia+T2DM mice. CONCLUSIONS Hyperhomocysteinemia potentiated systemic and vessel wall inflammation and vascular dysfunction partially via inflammatory monocyte subset induction in T2DM. Inflammatory monocyte may be a novel therapeutic target for insulin resistance, inflammation, and cardiovascular complications in hyperhomocysteinemia+T2DM.
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Affiliation(s)
- Pu Fang
- Center for Metabolic Disease Research, Lewis Kats School of Medicine, Temple University, Philadelphia, PA
| | - Xinyuan Li
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia PA
| | - Huimin Shan
- Center for Metabolic Disease Research, Lewis Kats School of Medicine, Temple University, Philadelphia, PA
| | - Jason J Saredy
- Center for Metabolic Disease Research, Lewis Kats School of Medicine, Temple University, Philadelphia, PA
| | - Ramon Cueto
- Center for Metabolic Disease Research, Lewis Kats School of Medicine, Temple University, Philadelphia, PA
| | - Jixiang Xia
- Center for Metabolic Disease Research, Lewis Kats School of Medicine, Temple University, Philadelphia, PA
| | - Xiaohua Jiang
- Center for Metabolic Disease Research, Lewis Kats School of Medicine, Temple University, Philadelphia, PA
| | - Xiao-Feng Yang
- Center for Metabolic Disease Research, Lewis Kats School of Medicine, Temple University, Philadelphia, PA
- Department of Pharmacology, Lewis Kats School of Medicine, Temple University, Philadelphia, PA
| | - Hong Wang
- Center for Metabolic Disease Research, Lewis Kats School of Medicine, Temple University, Philadelphia, PA
- Department of Pharmacology, Lewis Kats School of Medicine, Temple University, Philadelphia, PA
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10
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Bharath LP, Ip BC, Nikolajczyk BS. Adaptive Immunity and Metabolic Health: Harmony Becomes Dissonant in Obesity and Aging. Compr Physiol 2017; 7:1307-1337. [PMID: 28915326 DOI: 10.1002/cphy.c160042] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Adipose tissue (AT) is the primary energy reservoir organ, and thereby plays a critical role in energy homeostasis and regulation of metabolism. AT expands in response to chronic overnutrition or aging and becomes a major source of inflammation that has marked influence on systemic metabolism. The chronic, sterile inflammation that occurs in the AT during the development of obesity or in aging contributes to onset of devastating diseases such as insulin resistance, diabetes, and cardiovascular pathologies. Numerous studies have shown that inflammation in the visceral AT of humans and animals is a critical trigger for the development of metabolic syndrome. This work underscores the well-supported conclusion that the inflammatory immune response and metabolic pathways in the AT are tightly interwoven by multiple layers of relatively conserved mechanisms. During the development of diet-induced obesity or age-associated adiposity, cells of the innate and the adaptive immune systems infiltrate and proliferate in the AT. Macrophages, which dominate AT-associated immune cells in mouse models of obesity, but are less dominant in obese people, have been studied extensively. However, cells of the adaptive immune system, including T cells and B cells, contribute significantly to AT inflammation, perhaps more in humans than in mice. Lymphocytes regulate recruitment of innate immune cells into AT, and produce cytokines that influence the helpful-to-harmful inflammatory balance that, in turn, regulates organismal metabolism. This review describes inflammation, or more precisely, metabolic inflammation (metaflammation) with an eye toward the AT and the roles lymphocytes play in regulation of systemic metabolism during obesity and aging. © 2017 American Physiological Society. Compr Physiol 7:1307-1337, 2017.
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Affiliation(s)
- Leena P Bharath
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Blanche C Ip
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, USA.,Department of Molecular Pharmacology, Physiology and Biotechnology, Center of Biomedical Engineering, Brown University, Providence, Rhode Island, USA
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11
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He L, Law PTY, Wong CK, Chan JCN, Chan PKS. Exendin-4 Exhibits Enhanced Anti-tumor Effects in Diabetic Mice. Sci Rep 2017; 7:1791. [PMID: 28496193 PMCID: PMC5431757 DOI: 10.1038/s41598-017-01952-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 04/05/2017] [Indexed: 12/15/2022] Open
Abstract
Type 2 diabetes (T2D) is associated with increased risk of cancers. In this connection, we previously demonstrated the promoting effect of diabetes on HPV-associated carcinogenesis using a xenograft model in db/db diabetic mice. The underlying mechanism of this observation might be partly contributed by dysregulated immune response in diabetes. In this study, we hypothesized that the impaired anti-tumor immune response in diabetic status could be modulated by exendin-4, a glucagon-like protein receptor agonist which exhibits anti-diabetic effects. We inoculated 10-week old db/db mice with 2 × 107 CUP-1 cells (Human Papilloma Virus (HPV)-16 E7 transfected continuous cell line) subcutaneously underneath the scruff, and treated mice with high (30 nmol/kg) or low (10 nmol/kg) dose of exendin-4 for 13 days. Compared with control groups, exendin-4 suppressed subcutaneous tumor growth in a dose-dependent manner, accompanied by increased interferon (IFN)-γ secreting CD8+ cytotoxic T lymphocyte (CTL)/Foxp3+ regulatory T cell (Treg) ratio as well as Th1 proinflammatory cytokines IFN-γ and IL-2. Collectively, these findings suggested an anti-tumor effect of exendin-4 in diabetic conditions, which might be resulted from direct immunomodulation.
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Affiliation(s)
- Lan He
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR.,Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR.,Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR
| | - Priscilla T Y Law
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR
| | - Chun Kwok Wong
- Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR.,Institute of Chinese Medicine and State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR
| | - Juliana C N Chan
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR.,Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR.,Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR
| | - Paul K S Chan
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR.
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12
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Ansari AR, Liu H. Acute Thymic Involution and Mechanisms for Recovery. Arch Immunol Ther Exp (Warsz) 2017; 65:401-420. [PMID: 28331940 DOI: 10.1007/s00005-017-0462-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 03/12/2017] [Indexed: 12/14/2022]
Abstract
Acute thymic involution (ATI) is usually regarded as a virulence trait. It is caused by several infectious agents (bacteria, viruses, parasites, fungi) and other factors, including stress, pregnancy, malnutrition and chemotherapy. However, the complex mechanisms that operate during ATI differ substantially from each other depending on the causative agent. For instance, a transient reduction in the size and weight of the thymus and depletion of populations of T cell subsets are hallmarks of ATI in many cases, whereas severe disruption of the anatomical structure of the organ is also associated with some factors, including fungal, parasitic and viral infections. However, growing evidence shows that ATI may be therapeutically halted or reversed. In this review, we highlight the current progress in this field with respect to numerous pathological factors and discuss the possible mechanisms. Moreover, these new observations also show that ATI can be mechanistically reversed.
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Affiliation(s)
- Abdur Rahman Ansari
- Department of Basic Veterinary Medicine, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, 430070, Wuhan, Hubei, China.,Section of Anatomy and Histology, Department of Basic Sciences, College of Veterinary and Animal Sciences (CVAS), Jhang, Pakistan.,University of Veterinary and Animal Sciences (UVAS), Lahore, Pakistan
| | - Huazhen Liu
- Department of Basic Veterinary Medicine, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, 430070, Wuhan, Hubei, China.
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13
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Mathews JA, Krishnamoorthy N, Kasahara DI, Cho Y, Wurmbrand AP, Ribeiro L, Smith D, Umetsu D, Levy BD, Shore SA. IL-33 Drives Augmented Responses to Ozone in Obese Mice. ENVIRONMENTAL HEALTH PERSPECTIVES 2017; 125:246-253. [PMID: 27472835 PMCID: PMC5289908 DOI: 10.1289/ehp272] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Revised: 02/23/2016] [Accepted: 06/07/2016] [Indexed: 05/02/2023]
Abstract
BACKGROUND Ozone increases IL-33 in the lungs, and obesity augments the pulmonary effects of acute ozone exposure. OBJECTIVES We assessed the role of IL-33 in the augmented effects of ozone observed in obese mice. METHODS Lean wildtype and obese db/db mice were pretreated with antibodies blocking the IL-33 receptor, ST2, and then exposed to ozone (2 ppm for 3 hr). Airway responsiveness was assessed, bronchoalveolar lavage (BAL) was performed, and lung cells harvested for flow cytometry 24 hr later. Effects of ozone were also assessed in obese and lean mice deficient in γδ T cells and their wildtype controls. RESULTS AND DISCUSSION Ozone caused greater increases in BAL IL-33, neutrophils, and airway responsiveness in obese than lean mice. Anti-ST2 reduced ozone-induced airway hyperresponsiveness and inflammation in obese mice but had no effect in lean mice. Obesity also augmented ozone-induced increases in BAL CXCL1 and IL-6, and in BAL type 2 cytokines, whereas anti-ST2 treatment reduced these cytokines. In obese mice, ozone increased lung IL-13+ innate lymphoid cells type 2 (ILC2) and IL-13+ γδ T cells. Ozone increased ST2+ γδ T cells, indicating that these cells can be targets of IL-33, and γδ T cell deficiency reduced obesity-related increases in the response to ozone, including increases in type 2 cytokines. CONCLUSIONS Our data indicate that IL-33 contributes to augmented responses to ozone in obese mice. Obesity and ozone also interacted to promote type 2 cytokine production in γδ T cells and ILC2 in the lungs, which may contribute to the observed effects of IL-33. Citation: Mathews JA, Krishnamoorthy N, Kasahara DI, Cho Y, Wurmbrand AP, Ribeiro L, Smith D, Umetsu D, Levy BD, Shore SA. 2017. IL-33 drives augmented responses to ozone in obese mice. Environ Health Perspect 125:246-253; http://dx.doi.org/10.1289/EHP272.
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Affiliation(s)
- Joel A. Mathews
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
- Address correspondence to J.A. Mathews, Molecular and Integrative Physiological Sciences Program, Department of Environmental Health, Harvard School of Public Health, 665 Huntington Ave., Boston, MA 02115-6021 USA. Telephone: (617) 432-0989. E-mail:
| | - Nandini Krishnamoorthy
- Pulmonary and Critical Care Medicine, Harvard Institutes of Medicine Building, Boston, Massachusetts, USA
| | - David Itiro Kasahara
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Youngji Cho
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Allison Patricia Wurmbrand
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Luiza Ribeiro
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Dirk Smith
- Department of Inflammation Research, Amgen, Seattle, Washington, USA
| | - Dale Umetsu
- Genentech, South San Francisco, California, USA
| | - Bruce D. Levy
- Pulmonary and Critical Care Medicine, Harvard Institutes of Medicine Building, Boston, Massachusetts, USA
| | - Stephanie Ann Shore
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
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14
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Cohen S, Danzaki K, MacIver NJ. Nutritional effects on T-cell immunometabolism. Eur J Immunol 2017; 47:225-235. [PMID: 28054344 DOI: 10.1002/eji.201646423] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Revised: 11/23/2016] [Accepted: 01/02/2017] [Indexed: 12/14/2022]
Abstract
T cells are highly influenced by nutrient uptake from their environment, and changes in overall nutritional status, such as malnutrition or obesity, can result in altered T-cell metabolism and behavior. In states of severe malnutrition or starvation, T-cell survival, proliferation, and inflammatory cytokine production are all decreased, as is T-cell glucose uptake and metabolism. The altered T-cell function and metabolism seen in malnutrition is associated with altered adipokine levels, most particularly decreased leptin. Circulating leptin levels are low in malnutrition, and leptin has been shown to be a key link between nutrition and immunity. The current view is that leptin signaling is required to upregulate activated T-cell glucose metabolism and thereby fuel T-cell activation. In the setting of obesity, T cells have been found to have a key role in promoting the recruitment of inflammatory macrophages to adipose depots along with the production of inflammatory cytokines that promote the development of insulin resistance leading to diabetes. Deletion of T cells, key T-cell transcription factors, or pro-inflammatory T-cell cytokines prevents insulin resistance in obesity and underscores the importance of T cells in obesity-associated inflammation and metabolic disease. Altogether, T cells have a critical role in nutritional immunometabolism.
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Affiliation(s)
- Sivan Cohen
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA
| | - Keiko Danzaki
- Department of Pediatrics, Duke University School of Medicine, Durham, NC, USA
| | - Nancie J MacIver
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA
- Department of Pediatrics, Duke University School of Medicine, Durham, NC, USA
- Department of Immunology, Duke University School of Medicine, Durham, NC, USA
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15
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Extracellular HSP60 triggers tissue regeneration and wound healing by regulating inflammation and cell proliferation. NPJ Regen Med 2016; 1. [PMID: 28936359 PMCID: PMC5605149 DOI: 10.1038/npjregenmed.2016.13] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
After injury, zebrafish can restore many tissues that do not regenerate well in mammals, making it a useful vertebrate model for studying regenerative biology. We performed a systematic screen to identify genes essential for hair cell regeneration in zebrafish, and found that the heat shock protein Hspd1 (Hsp60) has a critical role in the regeneration of hair cells and amputated caudal fins. We showed HSP60-injected extracellularly promoted cell proliferation and regeneration in both hair cells and caudal fins. We showed that hspd1 mutant was deficient in leukocyte infiltration at the site of injury. Topical application of HSP60 in a diabetic mouse skin wound model dramatically accelerated wound healing compared with controls. Stimulation of human peripheral blood mononuclear cells with HSP60 triggered a specific induction of M2 phase CD163-positive monocytes. Our results demonstrate that the normally intracellular chaperonin HSP60 has an extracellular signalling function in injury inflammation and tissue regeneration, likely through promoting the M2 phase for macrophages.
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16
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Ekin A, Gezer C, Taner CE, Solmaz U, Gezer NS, Ozeren M. Prognostic Value of Fetal Thymus Size in Intrauterine Growth Restriction. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2016; 35:511-517. [PMID: 26860482 DOI: 10.7863/ultra.15.05039] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 06/22/2015] [Indexed: 06/05/2023]
Abstract
OBJECTIVES Our aim was to evaluate the size of the fetal thymus by sonography in pregnancies with intrauterine growth restriction (IUGR) and to search for a possible relationship between a small fetal thymus and adverse perinatal outcomes. METHODS The transverse diameter of the fetal thymus was prospectively measured in 150 healthy and 143 IUGR fetuses between 24 and 40 weeks' gestation. The fetuses with IUGR were further divided according to normal or abnormal Doppler assessment of the umbilical and middle cerebral arteries and ductus venosus. Measurements were compared with reference ranges from controls. To determine which perinatal outcomes were independently associated with a small fetal thymus, a multivariate logistic regression analysis was performed. RESULTS Thymus size was significantly lower in IUGR fetuses compared to controls (P < .05). Among IUGR fetuses, thymus size was significantly smaller in IUGR fetuses with abnormal Doppler flow compared to normal flow (P < .05). A small thymus in IUGR fetuses was independently associated with early delivery (odds ratio [OR], 1.24; 95% confidence interval [CI], 1.05-1.49; P= .023), respiratory distress syndrome (OR, 1.36; 95% CI, 1.09-1.78; P= .005), early neonatal sepsis (OR, 1.65; 95% CI, 1.11-2.42; P= .001), and a longer stay in the neonatal intensive care unit (OR, 1.33; 95% CI, 1.08-1.71; P = .017). CONCLUSIONS Intrauterine growth restriction is associated with fetal thymic involution, and a small fetal thymus is an early indicator of adverse perinatal outcomes in pregnancies complicated by IUGR.
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Affiliation(s)
- Atalay Ekin
- Department of Perinatology, Tepecik Training and Research Hospital, Izmir, Turkey (A.E., C.G., C.E.T., U.S., M.O.); and Department of Radiology, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey (N.S.G.).
| | - Cenk Gezer
- Department of Perinatology, Tepecik Training and Research Hospital, Izmir, Turkey (A.E., C.G., C.E.T., U.S., M.O.); and Department of Radiology, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey (N.S.G.)
| | - Cuneyt Eftal Taner
- Department of Perinatology, Tepecik Training and Research Hospital, Izmir, Turkey (A.E., C.G., C.E.T., U.S., M.O.); and Department of Radiology, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey (N.S.G.)
| | - Ulas Solmaz
- Department of Perinatology, Tepecik Training and Research Hospital, Izmir, Turkey (A.E., C.G., C.E.T., U.S., M.O.); and Department of Radiology, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey (N.S.G.)
| | - Naciye Sinem Gezer
- Department of Perinatology, Tepecik Training and Research Hospital, Izmir, Turkey (A.E., C.G., C.E.T., U.S., M.O.); and Department of Radiology, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey (N.S.G.)
| | - Mehmet Ozeren
- Department of Perinatology, Tepecik Training and Research Hospital, Izmir, Turkey (A.E., C.G., C.E.T., U.S., M.O.); and Department of Radiology, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey (N.S.G.)
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17
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Rehman Khan A, Awan FR. Leptin Resistance: A Possible Interface Between Obesity and Pulmonary-Related Disorders. Int J Endocrinol Metab 2016; 14:e32586. [PMID: 27279832 PMCID: PMC4896114 DOI: 10.5812/ijem.32586] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 12/01/2015] [Accepted: 01/03/2016] [Indexed: 01/09/2023] Open
Abstract
CONTEXT Under normal physiological conditions, leptin regulates body weight by creating a balance between food intake and energy expenditure. However, in obesity, serum leptin levels increase and become defective to retain energy balance. EVIDENCE ACQUISITION Elevated serum leptin levels are regarded as an established marker of obesity. It is also reported that obese asthmatic patients have maximum serum leptin levels compared to other groups such as non-obese asthmatics, and normal obese and non obese subjects without asthma. In addition to having an appetite suppressing effect, leptin also regulates certain acute-phase protein expressions including α-1 antitrypsin (A1AT) in the liver. RESULTS A1AT is a protease inhibitor that counterbalances the activity of the neutrophil elastase (NE) enzyme. A1AT reductions in obese-leptin resistant subjects lead to increased NE activity. The overactivity of NE degrades lung tissue proteins, which may lead to pulmonary disorders including asthma. CONCLUSIONS On the basis of prior studies, it could be hypothesized that, in obese asthmatic patients, the highest degree of leptin failure/resistance might lead to the creation of an imbalance between NE and its inhibitor A1AT. To ascertain this, large scale prospective studies are warranted to assess the comparative serum leptin and A1AT levels and NE activity in asthmatic non-obese and obese patients, simultaneously. Such studies might help to devise novel interventional therapies for the treatment of pulmonary-related problems including asthma, chronic obstructive pulmonary disorder (COPD), and other lung defects in susceptible obese subjects in the future.
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Affiliation(s)
- Abdul Rehman Khan
- Diabetes and Cardio-Metabolic Disorders Laboratory, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
- Obesity and Diabetes Research Laboratory, Department of Chemistry, University of Azad Jammu and Kashmir, Muzaffarabad, Pakistan
- Corresponding author: Abdul Rehman Khan, Obesity and Diabetes Research Laboratory, Department of Chemistry, University of Azad Jammu and Kashmir, Muzaffarabad, Pakistan. Tel: +92-3335742975, E-mail:
| | - Fazli Rabbi Awan
- Diabetes and Cardio-Metabolic Disorders Laboratory, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
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18
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Effect of Diet and Exercise on the Peripheral Immune System in Young Balb/c Mice. BIOMED RESEARCH INTERNATIONAL 2015; 2015:458470. [PMID: 26634209 PMCID: PMC4655039 DOI: 10.1155/2015/458470] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 10/13/2015] [Accepted: 10/20/2015] [Indexed: 01/29/2023]
Abstract
Although diet and exercise clearly have an influence on immune function, studies are scarce on the effect caused by exercise and the consumption of a carbohydrate-rich or fat-rich diet on the peripheral immune system. The aim of the present study was to evaluate the effect of exercise and the two aforementioned unbalanced diets on young Balb/c mice, especially in relation to BMI, the level of glucose, and the percentage of lymphocyte subpopulations in peripheral blood. The changes found were then related to the synthesis of leptin and adiponectin as well as the production of oxidative stress. The increase in BMI found with the carbohydrate-rich and fat-rich diets showed correlation with the levels of leptin and adiponectin. An increase in leptin and a decrease in adiponectin directly correlated with an increase in total lymphocytes and CD4+ cells and with a decrease in B cells. The increase in leptin also correlated with an increase in CD8+ cells. Glycemia and oxidative stress increased with the two unbalanced diets, negatively affecting the proliferation of total lymphocytes and the percentage of B cells, apparently by causing alterations in proteins through carbonylation. These alterations caused by an unbalanced diet were not modified by moderate exercise.
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19
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Sreenivasan J, Schlenner S, Franckaert D, Dooley J, Liston A. The thymoprotective function of leptin is indirectly mediated via suppression of obesity. Immunology 2015; 146:122-9. [PMID: 26059465 DOI: 10.1111/imm.12488] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 05/19/2015] [Accepted: 06/01/2015] [Indexed: 12/17/2022] Open
Abstract
Leptin is an adipokine that regulates metabolism and plays an important role as a neuroendocrine hormone. Leptin mediates these functions via the leptin receptor, and deficiency in either leptin or its receptor leads to obesity in humans and mice. Leptin has far reaching effects on the immune system, as observed in obese mice, which display decreased thymic function and increased inflammatory responses. With expression of the leptin receptor on T cells and supporting thymic epithelium, aberrant signalling through the leptin receptor has been thought to be the direct cause of thymic involution in obese mice. Here, we demonstrate that the absence of leptin receptor on either thymic epithelial cells or T cells does not lead to the loss of thymic function, demonstrating that the thymoprotective effect of leptin is mediated by obesity suppression rather than direct signalling to the cellular components of the thymus.
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Affiliation(s)
- Jayasree Sreenivasan
- VIB, Leuven, Belgium.,Department of Microbiology and Immunology, University of Leuven, Leuven, Belgium
| | - Susan Schlenner
- VIB, Leuven, Belgium.,Department of Microbiology and Immunology, University of Leuven, Leuven, Belgium
| | - Dean Franckaert
- VIB, Leuven, Belgium.,Department of Microbiology and Immunology, University of Leuven, Leuven, Belgium
| | - James Dooley
- VIB, Leuven, Belgium.,Department of Microbiology and Immunology, University of Leuven, Leuven, Belgium
| | - Adrian Liston
- VIB, Leuven, Belgium.,Department of Microbiology and Immunology, University of Leuven, Leuven, Belgium
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20
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Zabeau L, Jensen CJ, Seeuws S, Venken K, Verhee A, Catteeuw D, van Loo G, Chen H, Walder K, Hollis J, Foote S, Morris MJ, Van der Heyden J, Peelman F, Oldfield BJ, Rubio JP, Elewaut D, Tavernier J. Leptin's metabolic and immune functions can be uncoupled at the ligand/receptor interaction level. Cell Mol Life Sci 2014; 72:629-644. [PMID: 25098352 PMCID: PMC4293488 DOI: 10.1007/s00018-014-1697-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 07/17/2014] [Accepted: 07/28/2014] [Indexed: 01/21/2023]
Abstract
The adipocyte-derived cytokine leptin acts as a metabolic switch, connecting the body's metabolism to high-energy consuming processes such as reproduction and immune responses. We here provide genetic and biochemical evidence that the metabolic and immune functions of leptin can be uncoupled at the receptor level. First, homozygous mutant fatt/fatt mice carry a spontaneous splice mutation causing deletion of the leptin receptor (LR) immunoglobulin-like domain (IGD) in all LR isoforms. These mice are hyperphagic and morbidly obese, but display only minimal changes in size and cellularity of the thymus, and cellular immune responses are unaffected. These animals also displayed liver damage in response to concavalin A comparable to wild-type and heterozygous littermates. Second, treatment of healthy mice with a neutralizing nanobody targeting IGD induced weight gain and hyperinsulinaemia, but completely failed to block development of experimentally induced autoimmune diseases. These data indicate that leptin receptor deficiency or antagonism profoundly affects metabolism, with little concomitant effects on immune functions.
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Affiliation(s)
- Lennart Zabeau
- Department of Medical Protein Research, Faculty of Medicine and Health Sciences, Flanders Institute for Biotechnology, Ghent University, A. Baertsoenkaai 3, 9000, Ghent, Belgium
| | - Cathy J Jensen
- Neurogenetics Laboratory, Howard Florey Institute, Melbourne, Australia.,Department of Physiology, Monash University, Melbourne, Australia
| | - Sylvie Seeuws
- Laboratory for Molecular Immunology and Inflammation, Department of Rheumatology, Ghent University Hospital, Ghent University, De Pintelaan 185, 9000, Ghent, Belgium
| | - Koen Venken
- Laboratory for Molecular Immunology and Inflammation, Department of Rheumatology, Ghent University Hospital, Ghent University, De Pintelaan 185, 9000, Ghent, Belgium
| | - Annick Verhee
- Department of Medical Protein Research, Faculty of Medicine and Health Sciences, Flanders Institute for Biotechnology, Ghent University, A. Baertsoenkaai 3, 9000, Ghent, Belgium
| | - Dominiek Catteeuw
- Department of Medical Protein Research, Faculty of Medicine and Health Sciences, Flanders Institute for Biotechnology, Ghent University, A. Baertsoenkaai 3, 9000, Ghent, Belgium
| | - Geert van Loo
- Inflammation Research Center, Unit of Molecular Signal Transduction in Inflammation, Faculty of Sciences, Flanders Institute for Biotechnology, Ghent University, Ghent, Belgium
| | - Hui Chen
- Department of Pharmacology, University of Melbourne, Melbourne, Australia
| | - Ken Walder
- Metabolic Research Unit, School of Medicine, Deakin University, Geelong, Australia
| | - Jacob Hollis
- Department of Physiology, Monash University, Melbourne, Australia
| | - Simon Foote
- Menzies Research Institute, Hobart, Australia
| | - Margaret J Morris
- Department of Pharmacology, University of Melbourne, Melbourne, Australia
| | - José Van der Heyden
- Department of Medical Protein Research, Faculty of Medicine and Health Sciences, Flanders Institute for Biotechnology, Ghent University, A. Baertsoenkaai 3, 9000, Ghent, Belgium
| | - Frank Peelman
- Department of Medical Protein Research, Faculty of Medicine and Health Sciences, Flanders Institute for Biotechnology, Ghent University, A. Baertsoenkaai 3, 9000, Ghent, Belgium
| | - Brian J Oldfield
- Department of Physiology, Monash University, Melbourne, Australia
| | - Justin P Rubio
- Neurogenetics Laboratory, Howard Florey Institute, Melbourne, Australia
| | - Dirk Elewaut
- Laboratory for Molecular Immunology and Inflammation, Department of Rheumatology, Ghent University Hospital, Ghent University, De Pintelaan 185, 9000, Ghent, Belgium
| | - Jan Tavernier
- Department of Medical Protein Research, Faculty of Medicine and Health Sciences, Flanders Institute for Biotechnology, Ghent University, A. Baertsoenkaai 3, 9000, Ghent, Belgium.
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21
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Yoshida K, Nakashima E, Kubo Y, Yamaoka M, Kajimura J, Kyoizumi S, Hayashi T, Ohishi W, Kusunoki Y. Inverse associations between obesity indicators and thymic T-cell production levels in aging atomic-bomb survivors. PLoS One 2014; 9:e91985. [PMID: 24651652 PMCID: PMC3961282 DOI: 10.1371/journal.pone.0091985] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Accepted: 02/16/2014] [Indexed: 12/15/2022] Open
Abstract
Reduction of the naive T-cell population represents a deteriorating state in the immune system that occurs with advancing age. In animal model studies, obesity compromises the T-cell immune system as a result of enhanced adipogenesis in primary lymphoid organs and systemic inflammation. In this study, to test the hypothesis that obesity may contribute to the aging of human T-cell immunity, a thousand atomic-bomb survivors were examined for obesity status and ability to produce naive T cells, i.e., T-cell receptor excision circle (TREC) numbers in CD4 and CD8 T cells. The number of TRECs showed a strong positive correlation with naive T cell numbers, and lower TREC numbers were associated with higher age. We found that the TREC number was inversely associated with levels of obesity indicators (BMI, hemoglobin A1c) and serum CRP levels. Development of type-2 diabetes and fatty liver was also associated with lower TREC numbers. This population study suggests that obesity with enhanced inflammation is involved in aging of the human T-cell immune system. Given the fact that obesity increases the risk of numerous age-related diseases, attenuated immune competence is a possible mechanistic link between obesity and disease development among the elderly.
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Affiliation(s)
- Kengo Yoshida
- Department of Radiobiology/Molecular Epidemiology, Radiation Effects Research Foundation, Hiroshima, Japan
- * E-mail:
| | - Eiji Nakashima
- Department of Statistics, Radiation Effects Research Foundation, Hiroshima, Japan
| | - Yoshiko Kubo
- Department of Radiobiology/Molecular Epidemiology, Radiation Effects Research Foundation, Hiroshima, Japan
| | - Mika Yamaoka
- Department of Radiobiology/Molecular Epidemiology, Radiation Effects Research Foundation, Hiroshima, Japan
| | - Junko Kajimura
- Department of Radiobiology/Molecular Epidemiology, Radiation Effects Research Foundation, Hiroshima, Japan
| | - Seishi Kyoizumi
- Department of Radiobiology/Molecular Epidemiology, Radiation Effects Research Foundation, Hiroshima, Japan
| | - Tomonori Hayashi
- Department of Radiobiology/Molecular Epidemiology, Radiation Effects Research Foundation, Hiroshima, Japan
| | - Waka Ohishi
- Department of Clinical Studies, Radiation Effects Research Foundation, Hiroshima, Japan
| | - Yoichiro Kusunoki
- Department of Radiobiology/Molecular Epidemiology, Radiation Effects Research Foundation, Hiroshima, Japan
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22
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Moraes-Vieira PMM, Larocca RA, Bassi EJ, Peron JPS, Andrade-Oliveira V, Wasinski F, Araujo R, Thornley T, Quintana FJ, Basso AS, Strom TB, Câmara NOS. Leptin deficiency impairs maturation of dendritic cells and enhances induction of regulatory T and Th17 cells. Eur J Immunol 2014; 44:794-806. [PMID: 24271843 DOI: 10.1002/eji.201343592] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 11/08/2013] [Accepted: 11/20/2013] [Indexed: 01/09/2023]
Abstract
Leptin is an adipose-secreted hormone that plays an important role in both metabolism and immunity. Leptin has been shown to induce Th1-cell polarization and inhibit Th2-cell responses. Additionally, leptin induces Th17-cell responses, inhibits regulatory T (Treg) cells and modulates autoimmune diseases. Here, we investigated whether leptin mediates its activity on T cells by influencing dendritic cells (DCs) to promote Th17 and Treg-cell immune responses in mice. We observed that leptin deficiency (i) reduced the expression of DC maturation markers, (ii) decreased DC production of IL-12, TNF-α, and IL-6, (iii) increased DC production of TGF-β, and (iv) limited the capacity of DCs to induce syngeneic CD4(+) T-cell proliferation. As a consequence of this unique phenotype, DCs generated under leptin-free conditions induced Treg or TH 17 cells more efficiently than DCs generated in the presence of leptin. These data indicate important roles for leptin in DC homeostasis and the initiation and maintenance of inflammatory and regulatory immune responses by DCs.
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Affiliation(s)
- Pedro M M Moraes-Vieira
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil; Department of Medicine, Harvard Medical School, Beth Israel Medical Deaconess Center, Transplant Institute, Boston, MA, USA
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23
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Zhu M, Nikolajczyk BS. Immune cells link obesity-associated type 2 diabetes and periodontitis. J Dent Res 2014; 93:346-52. [PMID: 24393706 DOI: 10.1177/0022034513518943] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The clinical association between obesity-associated type 2 diabetes (T2D) and periodontitis, coupled with the increasing prevalence of these diseases, justifies studies to identify mechanisms responsible for the vicious feed-forward loop between systemic and oral disease. Changes in the immune system are critical for both obesity-associated T2D and periodontitis and therefore may link these diseases. Recent studies at the intersection of immunology and metabolism have greatly advanced our understanding of the role the immune system plays in the transition between obesity and obesity-associated T2D and have shown that immune cells exhibit similar functional changes in obesity/T2D and periodontitis. Furthermore, myeloid and lymphoid cells likely synergize to promote obesity/T2D-associated periodontitis despite complexities introduced by disease interaction. Thus the groundwork is being laid for researchers to exploit existing models to understand immune cell dysfunction and break the devastating relationship between obesity-associated T2D and oral disease.
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Affiliation(s)
- M Zhu
- Department of Microbiology, Boston University School of Medicine, Boston, MA, USA
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24
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Singh UP, Singh NP, Guan H, Busbee B, Price RL, Taub DD, Mishra MK, Fayad R, Nagarkatti M, Nagarkatti PS. The emerging role of leptin antagonist as potential therapeutic option for inflammatory bowel disease. Int Rev Immunol 2014; 33:23-33. [PMID: 23841494 PMCID: PMC4159716 DOI: 10.3109/08830185.2013.809071] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Inflammatory bowel disease (IBD) is a chronic relapsing immune-mediated inflammatory disorder that affects millions of people around the world. Leptin is a satiety hormone produced primarily by adipose tissue and acts both centrally and peripherally. Leptin has been shown to play a major role in regulating metabolism, which increases during IBD progression. Leptin mediates several physiological functions including elevated blood pressure, tumorogenesis, cardiovascular pathologies and enhanced immune response in many autoimmune diseases. Recent development of a leptin mutant antagonist that blocks leptin activity raises great hope and opens up new possibilities for therapy in many autoimmune diseases including IBD. To this end, preliminary data from an ongoing study in our laboratory on pegylated leptin antagonist mutant L39A/D40A/F41A (PEG-MLA) treatment shows an inhibition of chronic colitis in IL-10-/- mice. PEG-MLA effectively attenuates the overall clinical scores, reverses colitis-associated pathogenesis including a decrease in body weight, and decreases systemic leptin level. PEG-MLA induces both central and peripheral leptin deficiency by mediating the cellular immune response. In summary, after blocking leptin activity, the correlative outcome between leptin-mediated cellular immune response, systemic leptin levels, and amount of adipose tissue together may provide new strategies for therapeutic intervention in autoimmune diseases, especially for intestinal inflammation.
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Affiliation(s)
- Udai P. Singh
- Department of Pathology, Microbiology and Immunology, School of Medicine, University of South Carolina, Columbia, SC, USA
| | - Narendra P. Singh
- Department of Pathology, Microbiology and Immunology, School of Medicine, University of South Carolina, Columbia, SC, USA
| | - Hongbing Guan
- Department of Pathology, Microbiology and Immunology, School of Medicine, University of South Carolina, Columbia, SC, USA
| | - Brandon Busbee
- Department of Pathology, Microbiology and Immunology, School of Medicine, University of South Carolina, Columbia, SC, USA
| | - Robert L. Price
- Department of Cell and Developmental Biology, University of South Carolina, Columbia, SC, USA
| | - Dennis D. Taub
- Laboratory of Molecular Biology and Immunology, NIA-IRP, NIH, Baltimore, MD, USA
| | - Manoj K. Mishra
- Department of Math and Sciences, Alabama State University, Montgomery, AL, USA
| | - Raja Fayad
- Department of Exercise Science, Arnold School of Public Health, University of South Carolina, Columbia, SC, USA
| | - Mitzi Nagarkatti
- Department of Pathology, Microbiology and Immunology, School of Medicine, University of South Carolina, Columbia, SC, USA
| | - Prakash S. Nagarkatti
- Department of Pathology, Microbiology and Immunology, School of Medicine, University of South Carolina, Columbia, SC, USA
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Singh UP, Singh NP, Guan H, Busbee B, Price RL, Taub DD, Mishra MK, Fayad R, Nagarkatti M, Nagarkatti PS. Leptin antagonist ameliorates chronic colitis in IL-10⁻/⁻ mice. Immunobiology 2013; 218:1439-51. [PMID: 23726523 PMCID: PMC3778116 DOI: 10.1016/j.imbio.2013.04.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 04/27/2013] [Accepted: 04/27/2013] [Indexed: 02/07/2023]
Abstract
BACKGROUND Although the etiology of two major forms of inflammatory bowel disease (IBD), Crohn's disease (CD) and ulcerative colitis (UC) are unknown and evidence suggests that chronic intestinal inflammation is caused by an excessive immune response to mucosal antigens. Previous studies support the role for TGF-β1 through 3 in the initiation and maintenance of tolerance via the induction of regulatory T cells (Tregs) to control intestinal inflammation. Leptin, a satiety hormone produced primarily by adipose tissue, has been shown to increase during colitis progression and is believed to contribute to disease genesis and/or progression. AIM We investigated the ability of a pegylated leptin antagonist (PG-MLA) to ameliorate the development of chronic experimental colitis. RESULTS Compared to vehicle control animals, PG-MLA treatment of mice resulted in an (1) attenuated clinical score; (2) reversed colitis-associated pathogenesis including a decrease in body weight; (3) reduced systemic and mucosal inflammatory cytokine expression; (4) increased insulin levels and (5) enhanced systemic and mucosal Tregs and CD39⁺ Tregs in mice with chronic colitis. The percentage of systemic and mucosal TGF-β1, -β2 and -β3 expressing CD4⁺ T cells were augmented after PG-MLA treatment. The activation of STAT1 and STAT3 and the expression of Smad7 were also reduced after PG-MLA treatment in the colitic mice. These findings clearly suggest that PG-MLA treatment reduces intestinal Smad7 expression, restores TGF-β1-3 signaling and reduces STAT1/STAT3 activation that may increase the number of Tregs to ameliorate chronic colitis. CONCLUSION This study clearly links inflammation with the metabolic hormone leptin suggesting that nutritional status influences immune tolerance through the induction of functional Tregs. Inhibiting leptin activity through PG-MLA might provide a new and novel therapeutic strategy for the treatment of IBD.
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Affiliation(s)
- Udai P Singh
- Pathology, Microbiology and Immunology, School of Medicine, University of South Carolina, Columbia, SC 29208, USA.
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Saucillo DC, Gerriets VA, Sheng J, Rathmell JC, Maciver NJ. Leptin metabolically licenses T cells for activation to link nutrition and immunity. THE JOURNAL OF IMMUNOLOGY 2013; 192:136-44. [PMID: 24273001 DOI: 10.4049/jimmunol.1301158] [Citation(s) in RCA: 195] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Immune responses are highly energy-dependent processes. Activated T cells increase glucose uptake and aerobic glycolysis to survive and function. Malnutrition and starvation limit nutrients and are associated with immune deficiency and increased susceptibility to infection. Although it is clear that immunity is suppressed in times of nutrient stress, mechanisms that link systemic nutrition to T cell function are poorly understood. We show in this study that fasting leads to persistent defects in T cell activation and metabolism, as T cells from fasted animals had low glucose uptake and decreased ability to produce inflammatory cytokines, even when stimulated in nutrient-rich media. To explore the mechanism of this long-lasting T cell metabolic defect, we examined leptin, an adipokine reduced in fasting that regulates systemic metabolism and promotes effector T cell function. We show that leptin is essential for activated T cells to upregulate glucose uptake and metabolism. This effect was cell intrinsic and specific to activated effector T cells, as naive T cells and regulatory T cells did not require leptin for metabolic regulation. Importantly, either leptin addition to cultured T cells from fasted animals or leptin injections to fasting animals was sufficient to rescue both T cell metabolic and functional defects. Leptin-mediated metabolic regulation was critical, as transgenic expression of the glucose transporter Glut1 rescued cytokine production of T cells from fasted mice. Together, these data demonstrate that induction of T cell metabolism upon activation is dependent on systemic nutritional status, and leptin links adipocytes to metabolically license activated T cells in states of nutritional sufficiency.
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Affiliation(s)
- Donte C Saucillo
- Division of Pediatric Endocrinology and Diabetes, Duke University Medical Center, Durham, NC 27710
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MAŁGORZEWICZ SYLWIA, DARDZIŃSKA JOLANTAANNA, GNACIŃSKA MARIA, JANKUN JERZY, BRYL EWA, SWORCZAK KRZYSZTOF. Complex interaction between the immune system and adipose tissue (Review). Int J Mol Med 2013; 33:3-7. [DOI: 10.3892/ijmm.2013.1537] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 10/14/2013] [Indexed: 11/06/2022] Open
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Manarin R, Villar SR, Fernández Bussy R, González FB, Deschutter EV, Bonantini AP, Roggero E, Pérez AR, Bottasso O. Reciprocal influences between leptin and glucocorticoids during acute Trypanosoma cruzi infection. Med Microbiol Immunol 2013; 202:339-52. [DOI: 10.1007/s00430-013-0294-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 04/09/2013] [Indexed: 02/06/2023]
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Increase in the secretion of pro-inflammatory cytokines by peritoneal leucocytes in a genetic mouse model of obesity and metabolic syndrome. Proc Nutr Soc 2013. [DOI: 10.1017/s0029665113000839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Deng J, Liu Y, Yang M, Wang S, Zhang M, Wang X, Ko KH, Hua Z, Sun L, Cao X, Lu L. Leptin exacerbates collagen-induced arthritis via enhancement of Th17 cell response. ACTA ACUST UNITED AC 2012; 64:3564-73. [DOI: 10.1002/art.34637] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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31
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Chatzigeorgiou A, Karalis KP, Bornstein SR, Chavakis T. Lymphocytes in obesity-related adipose tissue inflammation. Diabetologia 2012; 55:2583-2592. [PMID: 22733483 DOI: 10.1007/s00125-012-2607-0] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 05/17/2012] [Indexed: 12/17/2022]
Abstract
Inflammation in the white adipose tissue (WAT) is considered a major player in the development of insulin resistance. The role of macrophages accumulating in the WAT during obesity, promoting WAT inflammation and insulin resistance is well established. In contrast, less is known about the role of lymphocytes. Recent studies have implicated different lymphocyte subsets in WAT inflammation. For instance, cytotoxic CD8(+) T cells infiltrating the WAT may contribute to the recruitment, differentiation and activation of macrophages. On the other hand, a differential role for CD4(+) Th1 and CD4(+) Th2 cells has been suggested. Levels of WAT regulatory T cells decrease during the course of obesity and may represent a crucial factor for the maintenance of insulin sensitivity. Moreover, activation of natural killer T cells, an innate-like T cell population, which recognises lipid antigens, promotes insulin resistance and WAT inflammation. Finally, B cells may infiltrate WAT very early in response to high-fat feeding and worsen glucose metabolism through modulation of T cells and the production of pathogenic antibodies. These interesting new findings however bear controversies and introduce novel, yet unanswered, questions. Here, we review and discuss the impact of the different lymphocyte subsets in obesity-related WAT inflammation and attempt to identify the open questions to be answered by future studies.
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Affiliation(s)
- A Chatzigeorgiou
- Department of Internal Medicine III, Division of Vascular Inflammation, Diabetes and Kidney, University Clinic Carl-Gustav-Carus, University of Dresden, Fetscherstrasse 74, 01307, Dresden, Germany.
- Institute of Physiology, University of Dresden, Dresden, Germany.
| | - K P Karalis
- Department of Internal Medicine III, University Clinic Carl-Gustav-Carus, University of Dresden, Dresden, Germany
- Developmental Biology Section, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
- Division of Endocrinology, Children's Hospital, Boston, MA, USA
| | - S R Bornstein
- Department of Internal Medicine III, University Clinic Carl-Gustav-Carus, University of Dresden, Dresden, Germany
| | - T Chavakis
- Department of Internal Medicine III, Division of Vascular Inflammation, Diabetes and Kidney, University Clinic Carl-Gustav-Carus, University of Dresden, Fetscherstrasse 74, 01307, Dresden, Germany.
- Institute of Physiology, University of Dresden, Dresden, Germany.
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Abstract
Obesity and related type 2 diabetes are increasing at epidemic proportions globally. It is now recognized that inflammatory responses mediated within the adipose tissue in obesity are central to the development of disease. Once initiated, chronic inflammation associated with obesity leads to the modulation of immune cell function. This review will focus specifically on the impact of obesity on γδ T cells, a T-cell subset that is found in high concentrations in epithelial tissues such as the skin, intestine, and lung. Epithelial γδ T cell function is of particular concern in obesity as they are the guardians of the epithelial barrier and mediate repair. A breakdown in their function, and subsequently the deterioration of the epithelium can result in dire consequences for the host. Obese patients are more prone to non-healing injuries, infection, and disease. The resulting inflammation from these pathologies further perpetuates the disease condition already present in obese hosts. Here we will provide insight into the immunomodulation of γδ T cells that occurs in the epithelial barrier during obesity and discuss current therapeutic options.
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Function of junctional adhesion molecules (JAMs) in leukocyte migration and homeostasis. Arch Immunol Ther Exp (Warsz) 2012; 61:15-23. [PMID: 22940878 DOI: 10.1007/s00005-012-0199-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Accepted: 07/23/2012] [Indexed: 01/09/2023]
Abstract
Homeostasis is a word widely used in the scientific community to refer to the property of a system to maintain its uniformity and functionality. In living organisms, the word refers to the concept enunciated 150 years ago by C. Bernard by which external variations must be compensated for in order to maintain internal conditions compatible with life. This is especially true in the case of highly dynamic system such as the hematopoietic system that requires the coordinated control of cell proliferation and death within specialized microenvironments that are anatomically distinct. As a consequence, hematopoietic cell adhesion and migration must be tightly controlled in order for hematopoietic cells to reach and to be maintained in appropriate microenvironments. The junctional adhesion molecules (JAMs) are adhesion molecules that belong to the immunoglobulin superfamily (IgSf) and that have been initially identified as important players controlling vascular permeability and leukocyte transendothelial migration. This involves the regulated localization of the JAMs at lateral endothelial cell/cell borders and their interaction with leukocyte integrins. More recently, some of the JAM family members have also been found to be expressed by stromal cells and to regulate chemokine secretion within lymphoid organs, acting not only on leukocyte transendothelial migration, but also on hematopoietic cell retention within specialized microenvironments. This review summarizes recent progress in understanding the role of the JAMs in leukocyte adhesion and migration to tentatively draw an integrated view of the homeostatic function of the JAMs within the hematopoietic system.
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Basu S, Dewangan S, Shukla RC, Anupurva S, Kumar A. Thymic involution as a predictor of early-onset neonatal sepsis. Paediatr Int Child Health 2012; 32:147-51. [PMID: 22824662 DOI: 10.1179/2046905512y.0000000018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
BACKGROUND Diagnosis of early-onset neonatal sepsis (EONS) is often difficult because of vague clinical signs and non-specific laboratory parameters. OBJECTIVE To assess the statistical validity of thymic size estimation as a diagnostic marker of EONS compared with cord blood interleukin-6 (IL-6) concentrations. SUBJECTS AND METHODS Thirty-two neonates delivered in hospital and admitted to the neonatal unit with EONS comprised the study group. EONS was diagnosed on the basis of development of clinical signs and symptoms of sepsis within 72 hours of birth in the presence of antenatal risk factors for chorio-amnionitis and a positive blood culture. Thirty-two gestational age- and gender-matched healthy neonates served as controls. Cord blood IL-6 concentrations were estimated by ELISA. Thymic size was assessed by sonological measurement of thymic dimensions (longitudinal and transverse diameters, thymic volume and thymic index) within 24 hours of birth in the study infants and the controls. Data were analyzed by SPSS 16.0. RESULTS Thymic size was significantly smaller whereas cord blood IL-6 concentrations were significantly higher (P<0.001) in the sepsis group than in the controls. Sensitivity and specificity of thymic dimensions were comparable to IL-6 concentrations for diagnosing EONS. Significant correlation was noted between reduction in thymic size and a rise in IL-6 concentrations. CONCLUSION Thymic involution can be used as a reliable diagnostic marker for EONS.
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Affiliation(s)
- Sriparna Basu
- Department of Pediatrics, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India.
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Fujita Y, Yanagida H, Mimori T, Jin ZX, Sakai T, Kawanami T, Sawaki T, Masaki Y, Fukushima T, Okazaki T, Umehara H. Prevention of fasting-mediated bone marrow atrophy by leptin administration. Cell Immunol 2011; 273:52-8. [PMID: 22196379 DOI: 10.1016/j.cellimm.2011.11.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Revised: 10/19/2011] [Accepted: 11/21/2011] [Indexed: 11/30/2022]
Abstract
Leptin is an adipokine that regulates body weight. In the current study, we demonstrate that continuous injection of leptin prevents the lymphocyte reduction observed in fasted mice, especially the immature B cell populations in the bone marrow. Although leptin administration reduced apoptotic cells in the bone marrow of fasted mice, it did not prevent glucocorticoid-mediated apoptosis in vitro. Bone marrow atrophy has also been shown in the leptin receptor-deficient db/db mice. In order to investigate the mechanisms underlying these processes, we transplanted bone marrow cells from db/db or control (+m/+m) mice into C.B-17/lcr-scid/scid mice. We found that the spleen and bone marrow B cell populations were completely reconstituted when db/db and +m/+m cells were transplanted into scid mice. Our findings suggest that direct interactions between leptin and bone marrow cells are not essential for the development of B cells in a metabologically normal environment.
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Affiliation(s)
- Yoshimasa Fujita
- Department of Hematology and Immunology, Kanazawa Medical University, Ishikawa, Japan.
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36
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Scotece M, Conde J, Gómez R, López V, Lago F, Gómez-Reino JJ, Gualillo O. Beyond fat mass: exploring the role of adipokines in rheumatic diseases. ScientificWorldJournal 2011; 11:1932-47. [PMID: 22194660 PMCID: PMC3236382 DOI: 10.1100/2011/290142] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Accepted: 09/23/2011] [Indexed: 12/16/2022] Open
Abstract
The cloning of leptin in 1994 by Zhang et al. introduced a novel concept about white adipose tissue (WAT) as a very dynamic organ that releases a plethora of immune and inflammatory mediators, such as adipokines and cytokines, which are involved in multiple diseases. Actually, adipokines exert potent modulatory actions on target tissues involved in rheumatic diseases including cartilage, synovial, bone and immune cells. The goal of this paper is to elucidate the recent findings concerning the involvement of adipokines in rheumatic diseases, such as rheumatoid arthritis (RA), osteoarthritis (OA), and systemic lupus erythematosus (SLE).
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Affiliation(s)
- Morena Scotece
- Laboratory of Neuroendocrine Interactions in Rheumatology and Inflammatory Diseases, SERGAS, Institute of Medical Research IDIS, Santiago University Clinical Hospital, 15706 Santiago de Compostela, Spain
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Role of central leptin signaling in the starvation-induced alteration of B-cell development. J Neurosci 2011; 31:8373-80. [PMID: 21653842 DOI: 10.1523/jneurosci.6562-10.2011] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Nutritional deprivation or malnutrition suppresses immune function in humans and animals, thereby conferring higher susceptibility to infectious diseases. Indeed, nutritional deprivation induces atrophy of lymphoid tissues such as thymus and spleen and decreases the number of circulating lymphocytes. Leptin, a major adipocytokine, is exclusively produced in the adipose tissue in response to the nutritional status and acts on the hypothalamus, thereby regulating energy homeostasis. Although leptin plays a critical role in the starvation-induced T-cell-mediated immunosuppression, little is known about its role in B-cell homeostasis under starvation conditions. Here we show the alteration of B-cell development in the bone marrow of fasted mice, characterized by decrease in pro-B, pre-B, and immature B cells and increase in mature B cells. Interestingly, intracerebroventricular leptin injection was sufficient to prevent the alteration of B-cell development of fasted mice. The alteration of B lineage cells in the bone marrow of fasted mice was markedly prevented by oral administration of glucocorticoid receptor antagonist RU486 (11β-[p-(dimethylamino)phenyl]-17β-hydroxy-17-(1-propynyl)estra-4,9-dien-3-one). It was also effectively prevented by intracerebroventricular injection of neuropeptide Y Y(1) receptor antagonist BIBP3226 [(2R)-5-(diaminomethylideneamino)-2-[(2,2-diphenylacetyl)amino]-N-[(4-hydroxyphenyl)methyl]pentanamide], along with suppression of the otherwise increased serum corticosterone concentrations. This study provides the first in vivo evidence for the role of central leptin signaling in the starvation-induced alteration of B-cell development. The data of this study suggest that the CNS, which is inherent to integrate information from throughout the organism, is able to control immune function.
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Lemos MP, Rhee KY, McKinney JD. Expression of the leptin receptor outside of bone marrow-derived cells regulates tuberculosis control and lung macrophage MHC expression. THE JOURNAL OF IMMUNOLOGY 2011; 187:3776-84. [PMID: 21859958 DOI: 10.4049/jimmunol.1003226] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Leptin is a pleiotropic hormone proposed to link nutritional status to the development of strong Th1 immunity. Because Mycobacterium tuberculosis control is affected by starvation and diabetes, we studied the role of the leptin receptor in regulating distinct immune cells during chronic infection. Infected db/db mice, bearing a natural mutation in the leptin receptor, have a markedly increased bacterial load in their lungs when compared with that of their wild-type counterparts. In response to M. tuberculosis infection, db/db mice exhibited disorganized granulomas, neutrophilia, and reduced B cell migration to the lungs, correlating with dysfunctional lung chemokine responses that include XCL1, CCL2, CXCL1, CXCL2, and CXCL13. In a db/db lung, myeloid cells were delayed in their production of inducible NO synthase and had reduced expression of MHC I and II. Although the Th1 cell response developed normally in the absence of leptin signaling, production of pulmonary IFN-γ was delayed and ineffective. Surprisingly, a proper immune response took place in bone marrow (BM) chimeras lacking leptin receptor exclusively in BM-derived cells, indicating that leptin acts indirectly on immune cells to modulate the antituberculosis response and bacterial control. Together, these findings suggest that the pulmonary response to M. tuberculosis is affected by the host's nutritional status via the regulation of non-BM-derived cells, not through direct action of leptin on Th1 immunity.
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Affiliation(s)
- Maria P Lemos
- The Rockefeller University, New York, NY 10021, USA.
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Sloan C, Tuinei J, Nemetz K, Frandsen J, Soto J, Wride N, Sempokuya T, Alegria L, Bugger H, Abel ED. Central leptin signaling is required to normalize myocardial fatty acid oxidation rates in caloric-restricted ob/ob mice. Diabetes 2011; 60:1424-34. [PMID: 21441440 PMCID: PMC3292315 DOI: 10.2337/db10-1106] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE ob/ob and db/db mice manifest myocardial hypertrophy, insulin resistance, altered substrate utilization, mitochondrial dysfunction, and lipid accumulation. This study was designed to determine the contribution of central and peripheral leptin signaling to myocardial metabolism and function in ob/ob and db/db mice in the absence of diabetes and morbid obesity. RESEARCH DESIGN AND METHODS Male ob/ob mice (aged 4 weeks) were caloric restricted by pairfeeding to a leptin-treated ob/ob group. In addition to determining glucose tolerance and circulating lipid concentrations, myocardial substrate metabolism and mitochondrial function were determined in saponin-permeabilized cardiac fibers. Second, experiments were performed to determine whether leptin treatment by intraperitoneal injection or intracerebroventricular infusion could normalize myocardial palmitate oxidation in caloric-restricted ob/ob mouse hearts. RESULTS Despite normalizing body weight and glucose tolerance, fat mass and circulating lipid levels remained increased in caloric-restricted ob/ob animals. Palmitate oxidation remained elevated in caloric-restricted ob/ob hearts and was normalized by intraperitoneal or intracerebroventricular leptin. Intraperitoneal and intracerebroventricular treatment also normalized circulating free fatty acid levels, myocardial fatty acid oxidation gene expression, and myocardial insulin sensitivity. CONCLUSIONS These data suggest that impaired hypothalamic leptin signaling is sufficient to increase myocardial fatty acid oxidation by increasing delivery of free fatty acid substrates and peroxisome proliferator-activated receptor-α ligands to the heart.
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Conde J, Scotece M, Gómez R, Gómez-Reino JJ, Lago F, Gualillo O. At the crossroad between immunity and metabolism: focus on leptin. Expert Rev Clin Immunol 2011; 6:801-8. [PMID: 20828288 DOI: 10.1586/eci.10.48] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
White adipose tissue is currently considered to be an active endocrine organ that secretes a plethora of factors named adipokines, most of them proinflammatory in nature, which probably contribute to low-level systemic inflammation; a state that is often present in metabolic syndrome-associated chronic pathologies such as obesity and atherosclerosis. Leptin is historically and indisputably one of the most important adipokines secreted by fat cells, with a variety of physiological roles related to the control of metabolism, energy homeostasis and inflammatory response. One of these functions is the connection between nutritional status and immune competence. Indeed, leptin has been shown to modulate both the innate and adaptive immune responses in both normal and pathological conditions. It has been shown that conditions characterized by low leptin levels are associated with increased susceptibility to infection. Conversely, immune-mediated disorders, such as autoimmune diseases, are associated with increased secretion of leptin and the production of proinflammatory pathogenic cytokines. Thus, leptin can easily be considered a frank mediator of the inflammatory/immune response.
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Affiliation(s)
- Javier Conde
- Research laboratory 9 (NEIRID LAB: Neuroendocrine Interactions in Rheumatology and Inflammation Disease), Building C, Level -2, Institute of Medical Research (IDIS), Santiago University Clinical Hospital, Calle Choupana s/n, Santiago de Compostela, 15706, Spain.
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Gove ME, Sherry CL, Pini M, Fantuzzi G. Generation of leptin receptor bone marrow chimeras: recovery from irradiation, immune cellularity, cytokine expression, and metabolic parameters. Obesity (Silver Spring) 2010; 18:2274-81. [PMID: 20395950 PMCID: PMC3640286 DOI: 10.1038/oby.2010.84] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Leptin regulates appetite and metabolism but also immunity and inflammation. Although functional leptin receptors (LepR) are expressed on hematopoietic cells, the role of these receptors in regulating immune function in vivo remains controversial. To clarify this issue, we performed bone marrow (BM) transplantation between obese db/db mice, lacking LepR, and wild-type (WT) mice. Results indicate that expression of LepR on BM-derived cells directly, though partially, regulates spleen and thymus cellularity, although the environment of db mice contributes to maintaining reduced cellularity of these organs. Selective expression of LepR on BM-derived cells also modulates leptin and adiponectin levels, with induction of a more favorable adipokine environment in the WT→db/db group. However, LepR signaling in BM-derived cells is not involved in regulation of body weight (BW) and composition, glycemia, hepatosteatosis or adipose tissue inflammation, although it modulates expression of interleukin (IL)-1β in the brain. Finally, data indicate that db mice have an increased susceptibility to irradiation compared to WT mice in terms of BW loss and recovery of leukocyte counts in peripheral blood. Therefore, interpretation of results obtained using BM chimeras between WT and db mice should take into account the difference in radiation sensitivity between the two types of animals.
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Affiliation(s)
- Melissa E. Gove
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Christina L. Sherry
- Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, Illinois, USA.
| | - Maria Pini
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Giamila Fantuzzi
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA
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Fiorina P, Pietramaggiori G, Scherer SS, Jurewicz M, Mathews JC, Vergani A, Thomas G, Orsenigo E, Staudacher C, La Rosa S, Capella C, Carothers A, Zerwes HG, Luzi L, Abdi R, Orgill DP. The Mobilization and Effect of Endogenous Bone Marrow Progenitor Cells in Diabetic Wound Healing. Cell Transplant 2010; 19:1369-81. [DOI: 10.3727/096368910x514288] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Diabetic patients suffer from impaired wound healing, characterized by only modest angiogenesis and cell proliferation. Stem cells may stimulate healing, but little is known about the kinetics of mobilization and function of bone marrow progenitor cells (BM-PCs) during diabetic wound repair. The objective of this study was to investigate the kinetics of BM-PC mobilization and their role during early diabetic wound repair in diabetic db/db mice. After wounding, circulating hematopoietic stem cells (Lin-c-Kit+Sca-1+) stably increased in the periphery and lymphoid tissue of db/db mice compared to unwounded controls. Peripheral endothelial progenitor cells (CD34+VEGFR+) were 2.5- and 3.5-fold increased on days 6 and 10 after wounding, respectively. Targeting the CXCR4—CXCL12 axis induced an increased release and engraftment of endogenous BM-PCs that was paralleled by an increased expression of CXCL12/SDF-1α in the wounds. Increased levels of peripheral and engrafted BM-PCs corresponded to stimulated angiogenesis and cell proliferation, while the addition of an agonist (GM-CSF) or an antagonist (ACK2) did not further modulate wound healing. Macroscopic histological correlations showed that increased levels of stem cells corresponded to higher levels of wound reepithelialization. After wounding, a natural release of endogenous BM-PCs was shown in diabetic mice, but only low levels of these cells homed in the healing tissue. Higher levels of CXCL12/SDF-1α and circulating stem cells were required to enhance their engraftment and biological effects. Despite controversial data about the functional impairment of diabetic BM-PCs, in this model our data showed a residual capacity of these cells to trigger angiogenesis and cell proliferation.
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Affiliation(s)
- Paolo Fiorina
- Transplantation Research Center, Division of Nephrology, Children's Hospital and Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Department of Medicine & Surgery, San Raffaele Scientific Institute, Milan, Italy
| | - Giorgio Pietramaggiori
- Plastic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Department of Surgery, University of Geneva, Geneva, Switzerland
| | - Saja S. Scherer
- Plastic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Department of Surgery, University of Geneva, Geneva, Switzerland
| | - Mollie Jurewicz
- Transplantation Research Center, Division of Nephrology, Children's Hospital and Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jasmine C. Mathews
- Plastic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Andrea Vergani
- Transplantation Research Center, Division of Nephrology, Children's Hospital and Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Department of Medicine & Surgery, San Raffaele Scientific Institute, Milan, Italy
| | - Gebhard Thomas
- Autoimmunity, Transplantation and Inflammation and Global Discovery Chemistry, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Elena Orsenigo
- Department of Medicine & Surgery, San Raffaele Scientific Institute, Milan, Italy
| | - Carlo Staudacher
- Department of Medicine & Surgery, San Raffaele Scientific Institute, Milan, Italy
| | - Stefano La Rosa
- Department of Pathology, Ospedale di Circolo and Department of Human Morphology, University of Insubria, Varese, Italy
| | - Carlo Capella
- Department of Pathology, Ospedale di Circolo and Department of Human Morphology, University of Insubria, Varese, Italy
| | - Adelaide Carothers
- Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Hans-Gunter Zerwes
- Autoimmunity, Transplantation and Inflammation and Global Discovery Chemistry, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Livio Luzi
- Facolta di Scienze Motorie, Università di Milano, Milan, Italy
| | - Reza Abdi
- Transplantation Research Center, Division of Nephrology, Children's Hospital and Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Dennis P. Orgill
- Plastic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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Induction of regulatory T cells decreases adipose inflammation and alleviates insulin resistance in ob/ob mice. Proc Natl Acad Sci U S A 2010; 107:9765-70. [PMID: 20445103 DOI: 10.1073/pnas.0908771107] [Citation(s) in RCA: 261] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Leptin-deficient ob/ob mice are overweight, develop insulin resistance, and serve as a model for type 2 diabetes (T2D). Studies suggest that inflammatory pathways are linked to the development of insulin resistance and T2D both in animals and humans. We asked whether the induction of regulatory T cells (Tregs) could alleviate the pathological and metabolic abnormalities in ob/ob mice. We induced TGF-beta-dependent CD4(+) latency-associated peptide (LAP)-positive Tregs by oral administration of anti-CD3 antibody plus beta-glucosylceramide. We found a decrease in pancreatic islet cell hyperplasia, fat accumulation in the liver, and inflammation in adipose tissue, accompanied by lower blood glucose and liver enzymes. In addition, treated animals had decreased CD11b(+)F4/80(+) macrophages and TNF-alpha in adipose tissue. Adoptive transfer of orally induced CD4(+)LAP(+) Tregs ameliorated metabolic and cytokine abnormalities. Our results demonstrate the importance of inflammation in T2D and identify a unique immunological approach for treatment of T2D by the induction of Tregs.
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Preferential effects of leptin on CD4 T cells in central and peripheral immune system are critically linked to the expression of leptin receptor. Biochem Biophys Res Commun 2010; 394:562-8. [PMID: 20227394 DOI: 10.1016/j.bbrc.2010.03.019] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Accepted: 03/03/2010] [Indexed: 11/22/2022]
Abstract
Leptin can enhance thymopoiesis and modulate the T-cell immune response. However, it remains controversial whether these effects correlate with the expression of leptin receptor, ObR. We herein addressed this issue by using in vivo animal models and in vitro culture systems. Leptin treatment in both ob/ob mice and normal young mice induced increases of CD4 SP thymocytes in thymus and CD4 T cells in the periphery. Interestingly, expression of the long form ObR was significantly restricted to DN, DP and CD4 SP, but not CD8 SP thymocytes. Moreover, in the reaggregated DP thymocyte cultures with leptin plus TSCs, leptin profoundly induced differentiation of CD4 SP but not CD8 SP thymocytes, suggesting that the effects of leptin on thymocyte differentiation might be closely related to the expression of leptin receptor in developing thymocytes. Surprisingly, ObR expression was markedly higher in peripheral CD4 T cells than that in CD8 T cells. Furthermore, leptin treatment with or without IL-2 and PHA had preferential effects on cell proliferation of CD4 T cells compared to that of CD8 T cells. Collectively, these data provide evidence that the effects of leptin on differentiation and proliferation of CD4 T cells might be closely related to the expression of leptin receptor.
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45
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Gruver AL, Ventevogel MS, Sempowski GD. Leptin receptor is expressed in thymus medulla and leptin protects against thymic remodeling during endotoxemia-induced thymus involution. J Endocrinol 2009; 203:75-85. [PMID: 19587263 PMCID: PMC3747557 DOI: 10.1677/joe-09-0179] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Leptin deficiency in mice results in chronic thymic atrophy, suppressed cell-mediated immunity, and decreased numbers of total lymphocytes, suggesting a key role for the metabolic hormone leptin in regulating thymopoiesis and overall immune homeostasis. Unfortunately, the thymus is highly susceptible to stress-induced acute involution. Prolonged thymus atrophy in stress situations can contribute to peripheral T cell deficiency or inhibit immune reconstitution. Little is known, however, about specific roles for leptin signaling in the thymus or the underlying mechanisms driving thymic involution or thymic recovery after acute stress. We report here that leptin receptor expression is restricted in thymus to medullary epithelial cells. Using a model of endotoxemia-induced acute thymic involution and recovery, we have demonstrated a role for supraphysiologic leptin in protection of thymic epithelial cells (TECs). We also present data in support of our hypothesis that leptin treatment decreases in vivo endotoxemia-induced apoptosis of double positive thymocytes and promotes proliferation of double negative thymocytes through a leptin receptor isoform b-specific mechanism. Furthermore, our studies have revealed that leptin treatment increases thymic expression of interleukin-7, an important soluble thymocyte growth factor produced by medullary TECs. Taken together, these studies support an intrathymic role for the metabolic hormone leptin in maintaining healthy thymic epithelium and promoting thymopoiesis, which is revealed when thymus homeostasis is perturbed by endotoxemia.
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Affiliation(s)
- Amanda L Gruver
- Department of Medicine, Duke University Medical Center, 102 Research Drive, Global Health Research Building (Room 1033), Durham, North Carolina 27710, USA
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Abstract
As the expanding obese population grows older, their successful immunologic aging will be critical to enhancing the health span. Obesity increases risk of infections and cancer, suggesting adverse effects on immune surveillance. Here, we report that obesity compromises the mechanisms regulating T-cell generation by inducing premature thymic involution. Diet-induced obesity reduced thymocyte counts and significantly increased apoptosis of developing T-cell populations. Obesity accelerated the age-related reduction of T-cell receptor (TCR) excision circle bearing peripheral lymphocytes, an index of recently generated T cells from thymus. Consistent with reduced thymopoiesis, dietary obesity led to reduction in peripheral naive T cells with increased frequency of effector-memory cells. Defects in thymopoiesis in obese mice were related with decrease in the lymphoid-primed multipotent progenitor (Lin-Sca1+Kit+ Flt3+) as well as common lymphoid progenitor (Lin-Sca1+CD117(lo)CD127+) pools. The TCR spectratyping analysis showed that obesity compromised V-beta TCR repertoire diversity. Furthermore, the obesity induced by melanocortin 4 receptor deficiency also constricted the T-cell repertoire diversity, recapitulating the thymic defects observed with diet-induced obesity. In middle-aged humans, progressive adiposity with or without type 2 diabetes also compromised thymic output. Collectively, these findings establish that obesity constricts T-cell diversity by accelerating age-related thymic involution.
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47
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Ceccarini G, Flavell RR, Butelman ER, Synan M, Willnow TE, Bar-Dagan M, Goldsmith SJ, Kreek MJ, Kothari P, Vallabhajosula S, Muir TW, Friedman JM. PET imaging of leptin biodistribution and metabolism in rodents and primates. Cell Metab 2009; 10:148-59. [PMID: 19656493 PMCID: PMC2867490 DOI: 10.1016/j.cmet.2009.07.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Revised: 05/26/2009] [Accepted: 07/03/2009] [Indexed: 12/21/2022]
Abstract
We have determined the systemic biodistribution of the hormone leptin by PET imaging. PET imaging using (18)F- and (68)Ga-labeled leptin revealed that, in mouse, the hormone was rapidly taken up by megalin (gp330/LRP2), a multiligand endocytic receptor localized in renal tubules. In addition, in rhesus monkeys, 15% of labeled leptin localized to red bone marrow, which was consistent with hormone uptake in rodent tissues. These data confirm a megalin-dependent mechanism for renal uptake in vivo. The significant binding to immune cells and blood cell precursors in bone marrow is also consistent with prior evidence showing that leptin modulates immune function. These experiments set the stage for similar studies in humans to assess the extent to which alterations of leptin's biodistribution might contribute to obesity; they also provide a general chemical strategy for (18)F labeling of proteins for PET imaging of other polypeptide hormones.
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Affiliation(s)
- Giovanni Ceccarini
- Laboratory of Molecular Genetics, Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
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48
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The influence of leptin on the activity of lung lymphocytes under simulated microgravity. Eur J Appl Physiol 2009; 107:335-44. [PMID: 19626337 DOI: 10.1007/s00421-009-1129-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/02/2009] [Indexed: 10/20/2022]
Abstract
Exposure to microgravity has been implicated in the compromised immune function in space travellers, resulting in opportunistic infections, poor wound healing, and cancer. Since recent studies have suggested that leptin was capable of modulating immune responses, the purpose of this study was to examine effects of microgravity on the activation and proliferation of rat lung lymphocytes and then to examine the effects of leptin-mediated signal transduction mechanisms of lymphocyte activation in these same conditions. In control conditions (T-flasks cultured cells) leptin was not able by itself to increase lymphocytes proliferation, or induce significant increase of either IL-2 production or expression of lymphocytes activation markers, such as CD25 and CD71, while it markedly enhanced the positive effects induced on these parameters by concanavalin A (ConA). Using clinostatic rotating wall vessel (RWV) bioreactors to simulate a microgravity environment, we found that ConA responsiveness was inhibited. Moreover, under these conditions, leptin was not able to reverse these impaired functions. Accordingly with the above cited inhibitory effects exerted by the simulated microgravity environment, evidence was also obtained of defects in lymphocyte intracellular signal transduction induced by the incubation in RWV bioreactors, namely concerning decreased ConA-mediated PKC activity, and reduced expression of NF-kappaB, c-fos, and ERK1/2. Again, leptin appeared to be unable in restoring a physiologic increase of these parameters, different from what could be observed after complementation of the ConA-mediated signalling with phorbol myristate acetate, which instead demonstrated to overcome the inhibition of lymphocytes activating functions, in the presence of simulated microgravity conditions.
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Abstract
As the cellular component of articular cartilage, chondrocytes are responsible for maintaining in a low-turnover state the unique composition and organization of the matrix that was determined during embryonic and postnatal development. In joint diseases, cartilage homeostasis is disrupted by mechanisms that are driven by combinations of biological mediators that vary according to the disease process, including contributions from other joint tissues. In osteoarthritis (OA), biomechanical stimuli predominate with up-regulation of both catabolic and anabolic cytokines and recapitulation of developmental phenotypes, whereas in rheumatoid arthritis (RA), inflammation and catabolism drive cartilage loss. In vitro studies in chondrocytes have elucidated signaling pathways and transcription factors that orchestrate specific functions that promote cartilage damage in both OA and RA. Thus, understanding how the adult articular chondrocyte functions within its unique environment will aid in the development of rational strategies to protect cartilage from damage resulting from joint disease. This review will cover current knowledge about the specific cellular and biochemical mechanisms that regulate cartilage homeostasis and pathology.
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Affiliation(s)
- Mary B Goldring
- Research Division, Hospital for Special Surgery, Affiliated with Weill College of Medicine of Cornell University, New York, NY 10021, USA.
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50
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Three questions about leptin and immunity. Brain Behav Immun 2009; 23:405-10. [PMID: 18996468 PMCID: PMC2699448 DOI: 10.1016/j.bbi.2008.10.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Revised: 10/14/2008] [Accepted: 10/16/2008] [Indexed: 12/11/2022] Open
Abstract
Leptin is a protein produced by adipocytes (and other cell types) that acts in the brain to regulate appetite and energy expenditure according to the amount of energy stored in adipose tissue. Leptin also exerts a variety of other functions, including important roles as a regulator of immune and inflammatory reactions. The present article is not meant to be a comprehensive review on leptin and immunity, but rather highlights a few controversial issues about leptin's place in the complex network of mediators regulating immune and inflammatory responses. Three issues are discussed: (1) Where am I going, or What is the cellular target of leptin for modulation of immune responses?; (2) Where am I coming from, or Is the cellular source important in determining leptin's effects on immune responses? and (3) What am I doing, or What are leptin's effects on immune and inflammatory responses?
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