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High Glucose and Carbonyl Stress Impair HIF-1-Regulated Responses and the Control of Mycobacterium tuberculosis in Macrophages. mBio 2022; 13:e0108622. [PMID: 36121152 PMCID: PMC9600926 DOI: 10.1128/mbio.01086-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Diabetes mellitus (DM) increases the risk of developing tuberculosis (TB), but the mechanisms behind diabetes-TB comorbidity are still undefined. Here, we studied the role of hypoxia-inducible factor-1 (HIF-1), a main regulator of metabolic and inflammatory responses, in the outcome of Mycobacterium tuberculosis infection of bone marrow-derived macrophages (BMM). We observed that M. tuberculosis infection of BMM increased the expression of HIF-1α and HIF-1-regulated genes. Treatment with the hypoxia mimetic deferoxamine (DFO) further increased levels of HIF-1-regulated immune and metabolic molecules and diminished the intracellular bacterial load in BMM and in the lungs of infected mice. The expression of HIF-1-regulated immunometabolic genes was reduced, and the intracellular M. tuberculosis levels were increased in BMM incubated with high-glucose levels or with methylglyoxal (MGO), a reactive carbonyl compound elevated in DM. In line with the in vitro findings, high M. tuberculosis levels and low HIF-1-regulated transcript levels were found in the lungs from hyperglycemic Leprdb/db compared with wild-type mice. The increased intracellular M. tuberculosis growth and the reduced expression of HIF-1-regulated metabolic and inflammatory genes in BMM incubated with MGO or high glucose were reverted by additional treatment with DFO. Hif1a-deficient BMM showed ablated responses of immunometabolic transcripts after mycobacterial infection at normal or high-glucose levels. We propose that HIF-1 may be targeted for the control of M. tuberculosis during DM. IMPORTANCE People living with diabetes who are also infected with M. tuberculosis are more likely to develop tuberculosis disease (TB). Why diabetic patients have an increased risk for developing TB is not well understood. Macrophages, the cell niche for M. tuberculosis, can express microbicidal mechanisms or be permissive to mycobacterial persistence and growth. Here, we showed that high glucose and carbonyl stress, which mediate diabetes pathogenesis, impair the control of intracellular M. tuberculosis in macrophages. Infection with M. tuberculosis stimulated the expression of genes regulated by the transcription factor HIF-1, a major controller of the responses to hypoxia, resulting in macrophage activation. High glucose and carbonyl compounds inhibited HIF-1 responses by macrophages. Mycobacterial control in the presence of glucose or carbonyl stress was restored by DFO, a compound that stabilizes HIF-1. We propose that HIF-1 can be targeted to reduce the risk of developing TB in people with diabetes.
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Ding Y, Haks MC, van den Eeden SJF, Ottenhoff THM, Harms AC, Hankemeier T, Eeza MNH, Matysik J, Alia A, Spaink HP. Leptin mutation and mycobacterial infection lead non-synergistically to a similar metabolic syndrome. Metabolomics 2022; 18:67. [PMID: 35933481 PMCID: PMC9356939 DOI: 10.1007/s11306-022-01921-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 07/07/2022] [Indexed: 11/25/2022]
Abstract
INTRODUCTION The leptin signaling pathway plays an important role as a key regulator of glucose homeostasis, metabolism control and systemic inflammatory responses. However, the metabolic effects of leptin on infectious diseases, for example tuberculosis (TB), are still little known. OBJECTIVES In this study, we aim to investigate the role of leptin on metabolism in the absence and presence of mycobacterial infection in zebrafish larvae and mice. METHODS Metabolites in entire zebrafish larvae and the blood of mice were studied using high-resolution magic-angle-spinning nuclear magnetic resonance (HR-MAS NMR) spectroscopy and mass spectrometry, respectively. For transcriptome studies of zebrafish larvae, deep RNA sequencing was used. RESULTS The results show that leptin mutation leads to a similar metabolic syndrome as caused by mycobacterial infection in the two species, characterized by the decrease of 11 amine metabolites. In both species, this metabolic syndrome was not aggravated further when the leptin mutant was infected by mycobacteria. Therefore, we conclude that leptin and mycobacterial infection are both impacting metabolism non-synergistically. In addition, we studied the transcriptomes of lepbibl54 mutant zebrafish larvae and wild type (WT) siblings after mycobacterial infection. These studies showed that mycobacteria induced a very distinct transcriptome signature in the lepbibl54 mutant zebrafish compared to WT sibling control larvae. Furthermore, lepbibl55 Tg (pck1:luc1) zebrafish line was constructed and confirmed this difference in transcriptional responses. CONCLUSIONS Leptin mutation and TB lead non-synergistically to a similar metabolic syndrome. Moreover, different transcriptomic responses in the lepbibl54 mutant and TB can lead to the similar metabolic end states.
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Affiliation(s)
- Yi Ding
- Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands
| | - Mariëlle C Haks
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Susan J F van den Eeden
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Tom H M Ottenhoff
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Amy C Harms
- Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Thomas Hankemeier
- Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Muhamed N H Eeza
- Institute of Analytical Chemistry, University of Leipzig, Leipzig, Germany
- Institute for Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany
| | - Jörg Matysik
- Institute of Analytical Chemistry, University of Leipzig, Leipzig, Germany
| | - A Alia
- Institute for Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Herman P Spaink
- Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands.
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Webber T, Ronacher K, Conradie-Smit M, Kleynhans L. Interplay Between the Immune and Endocrine Systems in the Lung: Implications for TB Susceptibility. Front Immunol 2022; 13:829355. [PMID: 35273609 PMCID: PMC8901994 DOI: 10.3389/fimmu.2022.829355] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 02/02/2022] [Indexed: 12/25/2022] Open
Abstract
The role of the endocrine system on the immune response, especially in the lung, remains poorly understood. Hormones play a crucial role in the development, homeostasis, metabolism, and response to the environment of cells and tissues. Major infectious and metabolic diseases, such as tuberculosis and diabetes, continue to converge, necessitating the development of a clearer understanding of the immune and endocrine interactions that occur in the lung. Research in bacterial respiratory infections is at a critical point, where the limitations in identifying and developing antibiotics is becoming more profound. Hormone receptors on alveolar and immune cells may provide a plethora of targets for host-directed therapy. This review discusses the interactions between the immune and endocrine systems in the lung. We describe hormone receptors currently identified in the lungs, focusing on the effect hormones have on the pulmonary immune response. Altered endocrine responses in the lung affect the balance between pro- and anti-inflammatory immune responses and play a role in the response to infection in the lung. While some hormones, such as leptin, resistin and lipocalin-2 promote pro-inflammatory responses and immune cell infiltration, others including adiponectin and ghrelin reduce inflammation and promote anti-inflammatory cell responses. Furthermore, type 2 diabetes as a major endocrine disease presents with altered immune responses leading to susceptibility to lung infections, such as tuberculosis. A better understanding of these interactions will expand our knowledge of the mechanisms at play in susceptibility to infectious diseases and may reveal opportunities for the development of host-directed therapies.
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Affiliation(s)
- Tariq Webber
- DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Katharina Ronacher
- Translational Research Institute, Mater Research Institute - The University of Queensland, Brisbane, QLD, Australia
| | - Marli Conradie-Smit
- Division of Endocrinology, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Léanie Kleynhans
- DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
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4
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[Diabetes and infection - a missing link really?]. MMW Fortschr Med 2019; 160:64-68. [PMID: 29335938 DOI: 10.1007/s15006-018-0096-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Abstract
In the present study, we identify and describe an important cross-talk between leptin signaling and macrophage functions in the context of Salmonella Typhimurium infection. Genetic ablation of leptin receptor or pharmacological antagonization of leptin augmented lysosomal functions in macrophages, reduced S. Typhimurium burden, and diminished inflammation both in vitro and in vivo. Leptin signaling activates mTORC2/Akt pathway through the down-regulation of Phlpp1 phosphatase, thus impairs lysosome-mediated pathogen clearance. The dynamic interplay between metabolism and immune responses in health and disease, by which different immune cells impact on metabolic processes, are being increasingly appreciated. However, the potential of master regulators of metabolism to control innate immunity are less understood. Here, we studied the cross-talk between leptin signaling and macrophage function in the context of bacterial infections. We found that upon infection with Gram-negative pathogens, such as Salmonella Typhimurium, leptin receptor (Lepr) expression increased in both mouse and human macrophages. Unexpectedly, both genetic Lepr ablation in macrophages and global pharmacologic leptin antagonization augmented lysosomal functions, reduced S. Typhimurium burden, and diminished inflammation in vitro and in vivo. Mechanistically, we show that leptin induction activates the mTORC2/Akt pathway and subsequently down-regulates Phlpp1 phosphatase, allowing for phosphorylated Akt to impair lysosomal-mediated pathogen clearance. These data highlight a link between leptin signaling, the mTORC2/Phlpp1/Akt axis, and lysosomal activity in macrophages and have important therapeutic implications for modulating innate immunity to combat Gram-negative bacterial infections.
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Holt MR, Miles JJ, Inder WJ, Thomson RM. Exploring immunomodulation by endocrine changes in Lady Windermere syndrome. Clin Exp Immunol 2019; 196:28-38. [PMID: 30697704 DOI: 10.1111/cei.13265] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/2019] [Indexed: 12/18/2022] Open
Abstract
Lung disease due to nontuberculous mycobacteria (NTM) occurs with disproportionate frequency in postmenopausal women with a unique phenotype and without clinically apparent predisposing factors. Dubbed 'Lady Windermere syndrome', the phenotype includes low body mass index (BMI), tall stature and higher than normal prevalence of scoliosis, pectus excavatum and mitral valve prolapse. Although the pathomechanism for susceptibility to NTM lung disease in these patients remains uncertain, it is likely to be multi-factorial. A role for the immunomodulatory consequences of oestrogen deficiency and altered adipokine production has been postulated. Altered levels of adipokines and dehydroepiandrosterone have been demonstrated in patients with NTM lung disease. Case reports of NTM lung disease in patients with hypopituitarism support the possibility that altered endocrine function influences disease susceptibility. This paper catalogues the evidence for immunomodulatory consequences of predicted endocrine changes in Lady Windermere syndrome, with emphasis on the immune response to NTM. Collectively, the data warrant further exploration of an endocrine link to disease susceptibility in Lady Windermere syndrome.
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Affiliation(s)
- M R Holt
- Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia.,Gallipoli Medical Research Institute, Greenslopes Private Hospital, Brisbane, Queensland, Australia
| | - J J Miles
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - W J Inder
- Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia.,Department of Diabetes and Endocrinology, Princess Alexandra Hospital, Brisbane, Queensland, Australia
| | - R M Thomson
- Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia.,Gallipoli Medical Research Institute, Greenslopes Private Hospital, Brisbane, Queensland, Australia
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Novita BD, Soediono EI, Nugraha J. Metformin associated inflammation levels regulation in type 2 diabetes mellitus-tuberculosis coinfection patients – A case report. ACTA ACUST UNITED AC 2018; 65:345-349. [DOI: 10.1016/j.ijtb.2018.08.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 08/31/2018] [Indexed: 01/27/2023]
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Mancuso P, Curtis JL, Freeman CM, Peters-Golden M, Weinberg JB, Myers MG. Ablation of the leptin receptor in myeloid cells impairs pulmonary clearance of Streptococcus pneumoniae and alveolar macrophage bactericidal function. Am J Physiol Lung Cell Mol Physiol 2018; 315:L78-L86. [PMID: 29565180 DOI: 10.1152/ajplung.00447.2017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Leptin is a pleiotropic hormone produced by white adipose tissue that regulates appetite and many physiological functions, including the immune response to infection. Genetic leptin deficiency in humans and mice impairs host defenses against respiratory tract infections. Since leptin deficiency is associated with obesity and other metabolic abnormalities, we generated mice that lack the leptin receptor (LepRb) in cells of the myeloid linage (LysM-LepRb-KO) to evaluate its impact in lean metabolically normal mice in a murine model of pneumococcal pneumonia. We observed higher lung and spleen bacterial burdens in LysM-LepRb-KO mice following an intratracheal challenge with Streptococcus pneumoniae. Although numbers of leukocytes recovered from bronchoalveolar lavage fluid did not differ between groups, we did observe higher levels of pulmonary IL-13 and TNFα in LysM-LepRb-KO mice 48 h post infection. Phagocytosis and killing of ingested S. pneumoniae were also impaired in alveolar macrophages (AMs) from LysM-LepRb-KO mice in vitro and were associated with reduced LTB4 and enhanced PGE2 synthesis in vitro. Pretreatment of AMs with LTB4 and the cyclooxygenase inhibitor, indomethacin, restored phagocytosis but not bacterial killing in vitro. These results confirm our previous observations in leptin-deficient ( ob/ob) and fasted mice and demonstrate that decreased leptin action, as opposed to metabolic irregularities associated with obesity or starvation, is responsible for the defective host defense against pneumococcal pneumonia. They also provide novel targets for therapeutic intervention in humans with bacterial pneumonia.
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Affiliation(s)
- Peter Mancuso
- Department of Environmental Health Sciences, University of Michigan , Ann Arbor, Michigan.,Department of Nutritional Sciences, School of Public Health, University of Michigan , Ann Arbor, Michigan.,Graduate Program in Immunology, University of Michigan , Ann Arbor, Michigan
| | - Jeffrey L Curtis
- Graduate Program in Immunology, University of Michigan , Ann Arbor, Michigan.,Division of Pulmonary and Critical Care Medicine, University of Michigan , Ann Arbor, Michigan.,Veterans Affairs, Ann Arbor Healthcare System, Ann Arbor, Michigan
| | - Christine M Freeman
- Graduate Program in Immunology, University of Michigan , Ann Arbor, Michigan.,Division of Pulmonary and Critical Care Medicine, University of Michigan , Ann Arbor, Michigan.,Veterans Affairs, Ann Arbor Healthcare System, Ann Arbor, Michigan
| | - Marc Peters-Golden
- Graduate Program in Immunology, University of Michigan , Ann Arbor, Michigan.,Division of Pulmonary and Critical Care Medicine, University of Michigan , Ann Arbor, Michigan
| | - Jason B Weinberg
- Department of Pediatrics and Communicable Diseases, University of Michigan , Ann Arbor, Michigan.,Department of Microbiology and Immunology, University of Michigan , Ann Arbor, Michigan
| | - Martin G Myers
- Department of Integrative and Molecular Physiology, University of Michigan , Ann Arbor, Michigan
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9
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Pearl JE, Das M, Cooper AM. Immunological roulette: Luck or something more? Considering the connections between host and environment in TB. Cell Mol Immunol 2018; 15:226-232. [PMID: 29375129 DOI: 10.1038/cmi.2017.145] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 10/24/2017] [Accepted: 10/29/2017] [Indexed: 02/07/2023] Open
Abstract
Accurate prediction of which patient will progress from a sub-clinical Mycobacterium tuberculosis infection to active tuberculosis represents an elusive, yet critical, clinical research objective. From the individual perspective, progression can be considered to be the product of a series of unfortunate events or even a run of bad luck. Here, we identify the subtle physiological relationships that can influence the odds of progression to active TB and how this progression may reflect directed dysbiosis in a number of interrelated systems. Most infected individuals who progress to disease have apparently good immune responses, but these responses are, at times, compromised by either local or systemic environmental factors. Obvious disease promoting processes, such as tissue-damaging granulomata, usually manifest in the lung, but illness is systemic. This apparent dichotomy between local and systemic reflects a clear need to define the factors that promote progression to active disease within the context of the body as a physiological whole. We discuss aspects of the host environment that can impact expression of immunity, including the microbiome, glucocorticoid-mediated regulation, catecholamines and interaction between the gut, liver and lung. We suggest the importance of integrating precision medicine into our analyses of experimental outcomes such that apparently conflicting results are not contentious, but rather reflect the impact of these subtle relationships with our environment and microbiota.
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Affiliation(s)
- John E Pearl
- Leicester Tuberculosis Research Group (LTBRG), Department of Infection Immunity and Inflammation, University of Leicester, University Road, Leicester LE1 7RH, UK
| | - Mrinal Das
- Leicester Tuberculosis Research Group (LTBRG), Department of Infection Immunity and Inflammation, University of Leicester, University Road, Leicester LE1 7RH, UK
| | - Andrea M Cooper
- Leicester Tuberculosis Research Group (LTBRG), Department of Infection Immunity and Inflammation, University of Leicester, University Road, Leicester LE1 7RH, UK
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10
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Pettengill MA, van Haren SD, Levy O. Soluble mediators regulating immunity in early life. Front Immunol 2014; 5:457. [PMID: 25309541 PMCID: PMC4173950 DOI: 10.3389/fimmu.2014.00457] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 09/08/2014] [Indexed: 12/15/2022] Open
Abstract
Soluble factors in blood plasma have a substantial impact on both the innate and adaptive immune responses. The complement system, antibodies, and anti-microbial proteins and peptides can directly interact with potential pathogens, protecting against systemic infection. Levels of these innate effector proteins are generally lower in neonatal circulation at term delivery than in adults, and lower still at preterm delivery. The extracellular environment also has a critical influence on immune cell maturation, activation, and effector functions, and many of the factors in plasma, including hormones, vitamins, and purines, have been shown to influence these processes for leukocytes of both the innate and adaptive immune systems. The ontogeny of plasma factors can be viewed in the context of a lower effectiveness of immune responses to infection and immunization in early life, which may be influenced by the striking neonatal deficiency of complement system proteins or enhanced neonatal production of the anti-inflammatory cytokine IL-10, among other ontogenic differences. Accordingly, we survey here a number of soluble mediators in plasma for which age-dependent differences in abundance may influence the ontogeny of immune function, particularly direct innate interaction and skewing of adaptive lymphocyte activity in response to infectious microorganisms and adjuvanted vaccines.
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Affiliation(s)
- Matthew Aaron Pettengill
- Department of Medicine, Division of Infectious Diseases, Boston Children's Hospital , Boston, MA , USA ; Harvard Medical School , Boston, MA , USA
| | - Simon Daniël van Haren
- Department of Medicine, Division of Infectious Diseases, Boston Children's Hospital , Boston, MA , USA ; Harvard Medical School , Boston, MA , USA
| | - Ofer Levy
- Department of Medicine, Division of Infectious Diseases, Boston Children's Hospital , Boston, MA , USA ; Harvard Medical School , Boston, MA , USA
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Vernooy JHJ, Ubags NDJ, Brusselle GG, Tavernier J, Suratt BT, Joos GF, Wouters EFM, Bracke KR. Leptin as regulator of pulmonary immune responses: involvement in respiratory diseases. Pulm Pharmacol Ther 2013; 26:464-72. [PMID: 23542720 PMCID: PMC4122282 DOI: 10.1016/j.pupt.2013.03.016] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 03/08/2013] [Accepted: 03/19/2013] [Indexed: 12/11/2022]
Abstract
Leptin is an adipocyte-derived hormone, recognized as a critical mediator of the balance between food intake and energy expenditure by signalling through its functional receptor (Ob-Rb) in the hypothalamus. Structurally, leptin belongs to the long-chain helical cytokine family, and is now known to have pleiotropic functions in both innate and adaptive immunity. The presence of the functional leptin receptor in the lung together with evidence of increased airspace leptin levels arising during pulmonary inflammation, suggests an important role for leptin in lung development, respiratory immune responses and eventually pathogenesis of inflammatory respiratory diseases. The purpose of this article is to review our current understanding of leptin and its functional role on the different resident cell types of the lung in health as well as in the context of three major respiratory conditions being chronic obstructive pulmonary disease (COPD), asthma, and pneumonia.
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Affiliation(s)
- Juanita H J Vernooy
- Department of Respiratory Medicine, Maastricht University Medical Center+, PO Box 5800, 6202 AZ Maastricht, The Netherlands.
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Abstract
Diabetes mellitus is one of the most prevalent conditions in the elderly and is associated with considerable morbidity and mortality, mainly from cardiovascular and renal complications. Furthermore, common perception associates diabetes with a generally increased susceptibility to infectious diseases, although epidemiologic data that would prove this are surprisingly scarce. However, it seems to be confirmed that diabetes predisposes to certain types of infection and death thereof, but it is less well understood if metabolic disturbances in diabetes itself, associated hyperglycemia and hyperinsulinemia or diabetes-associated comorbidities provide the link between diabetes and susceptibility to infections. In this review, I will summarize published reports on the incidence and risk for infectious diseases in diabetic people and give a comprehensive overview of the molecular mechanisms that have been suggested to explain the potentially altered immune response to pathogens in patients with diabetes.
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Affiliation(s)
- Sylvia Knapp
- Center for Molecular Medicine of the Austrian Academy of Sciences, and Division of Infectious Diseases and Tropical Medicine, Department of Medicine 1, Medical University of Vienna, Vienna, Austria.
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13
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Abstract
Enhanced susceptibility to infection has long been recognized in children with congenital deficiency of leptin or its receptor. Studies in mice have demonstrated that leptin deficiency affects both the innate and acquired immune systems. Here, we review recent studies that demonstrate the impact on immunity of a common non-synonomous polymorphism of the leptin receptor. In a Bangladesh cohort of children, the presence of two copies of the ancestral Q223 allele was significantly associated with resistance to amebiasis. Children and mice with at least one copy of the leptin receptor 223R mutation were more susceptible to amebic colitis. Leptin signaling in the intestinal epithelium and downstream STAT3 (signal transducer and activator of transcription 3) and SHP2 (Src homology phosphatase 2) signaling were required for protection in the murine model of amebic colitis. Murine models have also implicated leptin in protection from other infections, including Mycobacterium tuberculosis, Klebsiella pneumoniae, and Streptococcus pneumoniae. Thus, the role of leptin signaling in infectious disease and specifically leptin-mediated protection of the intestinal epithelium will be the focus of this review.
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Cooper AM, Torrado E. Protection versus pathology in tuberculosis: recent insights. Curr Opin Immunol 2012; 24:431-7. [PMID: 22613092 DOI: 10.1016/j.coi.2012.04.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 04/30/2012] [Indexed: 01/23/2023]
Abstract
Recent studies have revisited the roles of prime players in the immune response to tuberculosis (TB) and have highlighted novel functions of these players. Specifically, immunoregulatory mechanisms mediated by IFNγ have been delineated as well as a novel role for neutrophils in promoting antigen presentation. New insights into the interaction between the bacterium and phagocyte indicate that the bacterium actively promotes phagocyte necrosis rather than apoptosis and that this impacts generation of the acquired response. There are also many new examples of how the phagocyte responds to the bacteria and how it mediates control. The phenotype of protective T cells is also being re-examined. These developments provide promise for improved vaccine design and highlight the complexity of this disease.
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Affiliation(s)
- Andrea M Cooper
- The Trudeau Institute, Inc. 154 Algonquin Ave., Saranac Lake, NY 12983, United States.
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