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Cloonan SM, Kim K, Esteves P, Trian T, Barnes PJ. Mitochondrial dysfunction in lung ageing and disease. Eur Respir Rev 2020; 29:29/157/200165. [PMID: 33060165 DOI: 10.1183/16000617.0165-2020] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 09/25/2020] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial biology has seen a surge in popularity in the past 5 years, with the emergence of numerous new avenues of exciting mitochondria-related research including immunometabolism, mitochondrial transplantation and mitochondria-microbe biology. Since the early 1960s mitochondrial dysfunction has been observed in cells of the lung in individuals and in experimental models of chronic and acute respiratory diseases. However, it is only in the past decade with the emergence of more sophisticated tools and methodologies that we are beginning to understand how this enigmatic organelle regulates cellular homeostasis and contributes to disease processes in the lung. In this review, we highlight the diverse role of mitochondria in individual lung cell populations and what happens when these essential organelles become dysfunctional with ageing and in acute and chronic lung disease. Although much remains to be uncovered, we also discuss potential targeted therapeutics for mitochondrial dysfunction in the ageing and diseased lung.
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Affiliation(s)
- Suzanne M Cloonan
- Division of Pulmonary and Critical Care Medicine, Joan and Sanford I. Weill Dept of Medicine, New York, NY, USA.,School of Medicine, Trinity College Dublin and Tallaght University Hospital, Dublin, Ireland
| | - Kihwan Kim
- Division of Pulmonary and Critical Care Medicine, Joan and Sanford I. Weill Dept of Medicine, New York, NY, USA
| | - Pauline Esteves
- Univ-Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, Dépt de Pharmacologie, CIC 1401, Bordeaux, France.,INSERM, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CIC 1401, Bordeaux, France
| | - Thomas Trian
- Univ-Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, Dépt de Pharmacologie, CIC 1401, Bordeaux, France.,INSERM, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CIC 1401, Bordeaux, France
| | - Peter J Barnes
- National Heart and Lung Institute, Imperial College, London, UK
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2
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Lafuse WP, Rajaram MVS, Wu Q, Moliva JI, Torrelles JB, Turner J, Schlesinger LS. Identification of an Increased Alveolar Macrophage Subpopulation in Old Mice That Displays Unique Inflammatory Characteristics and Is Permissive to Mycobacterium tuberculosis Infection. THE JOURNAL OF IMMUNOLOGY 2019; 203:2252-2264. [PMID: 31511357 DOI: 10.4049/jimmunol.1900495] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 08/08/2019] [Indexed: 12/11/2022]
Abstract
The elderly population is more susceptible to pulmonary infections, including tuberculosis. In this article, we characterize the impact of aging on the phenotype of mouse alveolar macrophages (AMs) and their response to Mycobacterium tuberculosis. Uninfected AMs were isolated from bronchoalveolar lavage of young (3 mo) and old (18 mo) C57BL/6 mice. AMs from old mice expressed higher mRNA levels of CCL2, IFN-β, IL-10, IL-12p40, TNF-α, and MIF than young mice, and old mice contained higher levels of CCL2, IL-1β, IFN-β, and MIF in their alveolar lining fluid. We identified two distinct AM subpopulations, a major CD11c+ CD11b- population and a minor CD11c+ CD11b+ population; the latter was significantly increased in old mice (4-fold). Expression of CD206, TLR2, CD16/CD32, MHC class II, and CD86 was higher in CD11c+ CD11b+ AMs, and these cells expressed monocytic markers Ly6C, CX3CR1, and CD115, suggesting monocytic origin. Sorted CD11c+ CD11b+ AMs from old mice expressed higher mRNA levels of CCL2, IL-1β, and IL-6, whereas CD11c+ CD11b- AMs expressed higher mRNA levels of immune-regulatory cytokines IFN-β and IL-10. CD11c+ CD11b+ AMs phagocytosed significantly more M. tuberculosis, which expressed higher RNA levels of genes required for M. tuberculosis survival. Our studies identify two distinct AM populations in old mice: a resident population and an increased CD11c+ CD11b+ AM subpopulation expressing monocytic markers, a unique inflammatory signature, and enhanced M. tuberculosis phagocytosis and survival when compared with resident CD11c+ CD11b- AMs, which are more immune regulatory in nature.
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Affiliation(s)
- William P Lafuse
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210; and
| | - Murugesan V S Rajaram
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210; and
| | - Qian Wu
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210; and
| | - Juan I Moliva
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210; and.,Texas Biomedical Research Institute, San Antonio, TX 78227
| | - Jordi B Torrelles
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210; and.,Texas Biomedical Research Institute, San Antonio, TX 78227
| | - Joanne Turner
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210; and.,Texas Biomedical Research Institute, San Antonio, TX 78227
| | - Larry S Schlesinger
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210; and.,Texas Biomedical Research Institute, San Antonio, TX 78227
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3
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Piergallini TJ, Turner J. Tuberculosis in the elderly: Why inflammation matters. Exp Gerontol 2018; 105:32-39. [PMID: 29287772 PMCID: PMC5967410 DOI: 10.1016/j.exger.2017.12.021] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 12/22/2017] [Accepted: 12/22/2017] [Indexed: 12/20/2022]
Abstract
Growing old is associated with an increase in the basal inflammatory state of an individual and susceptibility to many diseases, including infectious diseases. Evidence is growing to support the concept that inflammation and disease susceptibility in the elderly is linked. Our studies focus on the infectious disease tuberculosis (TB), which is caused by Mycobacterium tuberculosis (M.tb), a pathogen that infects approximately one fourth of the world's population. Aging is a major risk factor for developing TB, and inflammation has been strongly implicated. In this review we will discuss the relationship between inflammation in the lung and susceptibility to develop and succumb to TB in old age. Further understanding of the relationship between inflammation, age, and M.tb will lead to informed decisions about TB prevention and treatment strategies that are uniquely designed for the elderly.
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Affiliation(s)
- Tucker J Piergallini
- Texas Biomedical Research Institute, San Antonio, TX 78227, United States; College of Medicine, The Ohio State University, Columbus, OH 43210, United States
| | - Joanne Turner
- Texas Biomedical Research Institute, San Antonio, TX 78227, United States.
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4
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Faridgohar M, Nikoueinejad H. New findings of Toll-like receptors involved in Mycobacterium tuberculosis infection. Pathog Glob Health 2017; 111:256-264. [PMID: 28715935 DOI: 10.1080/20477724.2017.1351080] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Tuberculosis (TB), an important issue in the present age, affects millions of people each year. The infectious agent of TB, Mycobacterium tuberculosis (Mtb), interacts with the immune system which prevents the development of this bacterium as much as possible. In fact, the receptors on the surface of immune cells identify the bacteria, one of which is Toll-like receptors (TLRs). Different TLRs including 2, 4, 9 and 8 play critical roles in tuberculosis infection. In this paper, we focused on the role of TLRs which interact with different components of Mtb and, consequently, prevent the entrance and influence of bacteria on the body.
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Affiliation(s)
- Majid Faridgohar
- a Molecular Biology Research Center , Baqiyatallah University of Medical Sciences , Tehran , Iran
| | - Hassan Nikoueinejad
- b Nephrology and Urology Research Center , Baqiyatallah University of Medical Sciences , Tehran , Iran
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5
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Lim JS, Nguyen KCT, Nguyen CT, Jang I, Han JM, Fabian C, Lee SE, Rhee JH, Cho KA. Flagellin-dependent TLR5/caveolin-1 as a promising immune activator in immunosenescence. Aging Cell 2015. [PMID: 26223660 PMCID: PMC4568978 DOI: 10.1111/acel.12383] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The age-associated decline of immune responses causes high susceptibility to infections and reduced vaccine efficacy in the elderly. However, the mechanisms underlying age-related deficits are unclear. Here, we found that the expression and signaling of flagellin (FlaB)-dependent Toll-like receptor 5 (TLR5), unlike the other TLRs, were well maintained in old macrophages, similar to young macrophages. The expression and activation of TLR5/MyD88, but not TLR4, were sensitively regulated by the upregulation of caveolin-1 in old macrophages through direct interaction. This interaction was also confirmed using macrophages from caveolin-1 or MyD88 knockout mice. Because TLR5 and caveolin-1 were well expressed in major old tissues including lung, skin, intestine, and spleen, we analyzed in vivo immune responses via a vaccine platform with FlaB as a mucosal adjuvant for the pneumococcal surface protein A (PspA) against Streptococcus pneumoniae infection in young and aged mice. The FlaB-PspA fusion protein induced a significantly higher level of PspA-specific IgG and IgA responses and demonstrated a high protective efficacy against a lethal challenge with live S. pneumoniae in aged mice. These results suggest that caveolin-1/TLR5 signaling plays a key role in age-associated innate immune responses and that FlaB-PspA stimulation of TLR5 may be a new strategy for a mucosal vaccine adjuvant against pneumococcal infection in the elderly.
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Affiliation(s)
- Jae Sung Lim
- Department of Biochemistry Chonnam National University Medical School Gwangju 501‐746 South Korea
| | - Kim Cuc Thi Nguyen
- Department of Biochemistry Chonnam National University Medical School Gwangju 501‐746 South Korea
- Center for Creative Biomedical Scientists Chonnam National University Medical School Gwangju 501‐746 South Korea
| | - Chung Truong Nguyen
- Clinical Vaccine R&D Center Chonnam National University Hwasun Hospital 160 Ilsim‐Ri Hwasun‐gun Jeonnam 519‐809 South Korea
| | - Ik‐Soon Jang
- Division of Life Science Korea Basic Science Institute Daejeon 305‐333 South Korea
| | - Jung Min Han
- Department of Integrated OMICS for Biomedical Science Yonsei University Seoul 120‐749 South Korea
- College of Pharmacy Yonsei University Incheon 406‐840 South Korea
| | - Claire Fabian
- Department of Immunology Fraunhofer Institute for Cell Therapy and Immunology (IZI) University of Leipzig 04103 Leipzig Germany
- Translational Center for Regenerative Medicine (TRM) University of Leipzig 04103 Leipzig Germany
| | - Shee Eun Lee
- Clinical Vaccine R&D Center Chonnam National University Hwasun Hospital 160 Ilsim‐Ri Hwasun‐gun Jeonnam 519‐809 South Korea
- Dental Science Research Institute School of Dentistry Chonnam National University Gwangju 500‐757 South Korea
| | - Joon Haeng Rhee
- Clinical Vaccine R&D Center Chonnam National University Hwasun Hospital 160 Ilsim‐Ri Hwasun‐gun Jeonnam 519‐809 South Korea
- Department of Microbiology Chonnam National University Medical School Gwangju 501‐746 South Korea
| | - Kyung A Cho
- Department of Biochemistry Chonnam National University Medical School Gwangju 501‐746 South Korea
- Center for Creative Biomedical Scientists Chonnam National University Medical School Gwangju 501‐746 South Korea
- Clinical Vaccine R&D Center Chonnam National University Hwasun Hospital 160 Ilsim‐Ri Hwasun‐gun Jeonnam 519‐809 South Korea
- Research Institute of Medical Sciences Chonnam National University Medical School Gwangju 501‐746 South Korea
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6
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Association between Maturation and Aging and Pulmonary Responses in Animal Models of Lung Injury. Anesthesiology 2015; 123:389-408. [DOI: 10.1097/aln.0000000000000687] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Abstract
Background:
Advanced age is associated with an increased susceptibility and mortality of the acute respiratory distress syndrome. This may be due to the progressive changes in innate immune responses and intrinsic properties of the lung that occur during the process of aging. Therefore, this study assesses the association between maturation and aging and pulmonary responses to injury in animal models of lung injury.
Methods:
A systematic search was conducted in PubMed, EMBASE (up to June 2014) and in the references of relevant articles to identify the studies using in vivo models of lung injury caused by an acute pulmonary insult, in which at least two age groups were compared. Because methodological diversity precluded combining these studies in a quantitative meta-analysis, data are presented based on the qualitative comparison with the adult group.
Results:
Of the 2,840 identified studies, 51 were included in this review. Most studies showed that, in response to a pulmonary insult, increasing age is associated with more pulmonary inflammation, edema, alveolar damage, and higher mortality. In addition, results indicate the existence of age-dependent changes in key components of the intracellular signaling pathways involved in the inflammatory response.
Conclusions:
Increasing age seems to be correlated with exaggerated pulmonary responses to injury, ultimately leading to more severe lung injury. Pulmonary inflammation seems relatively suppressed in infants/juveniles, whereas in the middle aged/elderly, the inflammatory response seems delayed but aggravated. This implies that investigators and clinicians need to use caution about extrapolating results from adolescent or youngadult animals to pediatric or elderly patients in clinical practice.
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8
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Canan CH, Gokhale NS, Carruthers B, Lafuse WP, Schlesinger LS, Torrelles JB, Turner J. Characterization of lung inflammation and its impact on macrophage function in aging. J Leukoc Biol 2014; 96:473-80. [PMID: 24935957 DOI: 10.1189/jlb.4a0214-093rr] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Systemic inflammation that occurs with increasing age (inflammaging) is thought to contribute to the increased susceptibility of the elderly to several disease states. The elderly are at significant risk for developing pulmonary disorders and infectious diseases, but the contribution of inflammation in the pulmonary environment has received little attention. In this study, we demonstrate that the lungs of old mice have elevated levels of proinflammatory cytokines and a resident population of highly activated pulmonary macrophages that are refractory to further activation by IFN-γ. The impact of this inflammatory state on macrophage function was determined in vitro in response to infection with M.tb. Macrophages from the lungs of old mice secreted more proinflammatory cytokines in response to M.tb infection than similar cells from young mice and also demonstrated enhanced M.tb uptake and P-L fusion. Supplementation of mouse chow with the NSAID ibuprofen led to a reversal of lung and macrophage inflammatory signatures. These data indicate that the pulmonary environment becomes inflammatory with increasing age and that this inflammatory environment can be reversed with ibuprofen.
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Affiliation(s)
- Cynthia H Canan
- Department of Microbial Infection and Immunity, College of Medicine, and Center for Microbial Interface Biology, The Ohio State University, Columbus Ohio, USA
| | - Nandan S Gokhale
- Department of Microbial Infection and Immunity, College of Medicine, and Center for Microbial Interface Biology, The Ohio State University, Columbus Ohio, USA
| | - Bridget Carruthers
- Department of Microbial Infection and Immunity, College of Medicine, and Center for Microbial Interface Biology, The Ohio State University, Columbus Ohio, USA
| | - William P Lafuse
- Department of Microbial Infection and Immunity, College of Medicine, and Center for Microbial Interface Biology, The Ohio State University, Columbus Ohio, USA
| | - Larry S Schlesinger
- Department of Microbial Infection and Immunity, College of Medicine, and Center for Microbial Interface Biology, The Ohio State University, Columbus Ohio, USA
| | - Jordi B Torrelles
- Department of Microbial Infection and Immunity, College of Medicine, and Center for Microbial Interface Biology, The Ohio State University, Columbus Ohio, USA
| | - Joanne Turner
- Department of Microbial Infection and Immunity, College of Medicine, and Center for Microbial Interface Biology, The Ohio State University, Columbus Ohio, USA
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9
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Navigating through the maze of TLR2 mediated signaling network for better mycobacterium infection control. Biochimie 2014; 102:1-8. [PMID: 24594065 DOI: 10.1016/j.biochi.2014.02.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 02/21/2014] [Indexed: 12/12/2022]
Abstract
Toll-like receptor 2 (TLR2), a member of pattern recognition receptors (PRRs) abundant on macrophages, dendritic cells (DCs) and respiratory epithelial cells lining the lung, plays critical role in host immune response against Mycobacterium tuberculosis (MTB) infection. TLR2-mediated elimination of MTB involves multiple pathways such as promoting DCs maturation, generating biased Th1, Th2, Th17 type response, regulating the macrophage activation and cytokine secretion. MTB can also hijack the TLR2 signaling to subvert the host immunity by dampening the macrophages response to IFN-γ, suppressing the processing and presentation of antigens. This review summarizes the intricate network of TLR2-mediated signaling and Mycobacteria effectors involved in MTB-host interaction with an aim to find better target for improved tuberculosis control, especially the host-derived therapy targets. TLR2 agonists with potential to be included in novel tuberculosis vaccines are also discussed.
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10
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Krone CL, van de Groep K, Trzciński K, Sanders EAM, Bogaert D. Immunosenescence and pneumococcal disease: an imbalance in host-pathogen interactions. THE LANCET RESPIRATORY MEDICINE 2013; 2:141-53. [PMID: 24503269 DOI: 10.1016/s2213-2600(13)70165-6] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Respiratory infections are among the most important causes of morbidity and mortality from infectious diseases worldwide. The most common causative bacterium, Streptococcus pneumoniae, frequently colonises the upper respiratory tract, where it resides mostly asymptomatically. Occasionally, however, S pneumoniae can cause severe disease such as pneumonia. Local host immunity is essential to control colonising pathogens by preventing overgrowth, spread, and invasion. However, age-related immune deficits in elderly people, known as immunosenescence, might contribute to increased disease burden. We review present knowledge about immunosenescence in the respiratory tract against Gram-positive bacteria, particularly S pneumoniae. We discuss the possible underdetection of pneumococcal colonisation in elderly people, and suggest changes to present surveillance methods to improve understanding of the relation between colonisation and disease. We conclude that present knowledge about alteration of host-pathogen interactions by immunosenescence in the respiratory tract is insufficient, and that research is needed to enable improved measures for prevention.
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Affiliation(s)
- Cassandra L Krone
- Pediatric Immunology and Infectious Diseases, University Medical Center Utrecht, WKZ, Utrecht, Netherlands
| | - Kirsten van de Groep
- Pediatric Immunology and Infectious Diseases, University Medical Center Utrecht, WKZ, Utrecht, Netherlands
| | - Krzysztof Trzciński
- Pediatric Immunology and Infectious Diseases, University Medical Center Utrecht, WKZ, Utrecht, Netherlands
| | - Elizabeth A M Sanders
- Pediatric Immunology and Infectious Diseases, University Medical Center Utrecht, WKZ, Utrecht, Netherlands
| | - Debby Bogaert
- Pediatric Immunology and Infectious Diseases, University Medical Center Utrecht, WKZ, Utrecht, Netherlands.
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11
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Guerra-Laso JM, González-García S, González-Cortés C, Diez-Tascón C, López-Medrano R, Rivero-Lezcano OM. Macrophages from elders are more permissive to intracellular multiplication of Mycobacterium tuberculosis. AGE (DORDRECHT, NETHERLANDS) 2013; 35:1235-50. [PMID: 22791369 PMCID: PMC3705107 DOI: 10.1007/s11357-012-9451-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 06/24/2012] [Indexed: 05/15/2023]
Abstract
The elderly account for a disproportionate share of all tuberculosis cases, and the population ageing may not fully explain this phenomenon. We have performed in vitro infection experiments to investigate whether there is an immunological basis for the apparent susceptibility of elders to tuberculosis. In our infection model, Mycobacterium tuberculosis induces a higher production of interleukin (IL)-6 and reactive oxygen species in macrophages from elders than from younger adults. This response did not prevent, however, an increased multiplication of M. tuberculosis in macrophages from elders as compared with the growth observed within cells from adults. By performing a factorial experiment, we have found that IFN-γ, but not IL-1β, IL-6 or TNF-α, stimulate the macrophages to restrict the multiplication of the bacterium in macrophages from elders. Although monocytes from elders seem to be in a higher level of activation, we present evidences that protein tyrosine phosphorylation response induced by M. tuberculosis is stronger in monocytes from adults than from elders. Using a protein array that detects 71 tyrosine phosphorylated kinases, we identified Pyk2 as the only kinase that displayed a difference of intensity larger than 50 % in adults than in elders. Furthermore, monocytes from elders that were incubated in the presence of tyrosine kinase inhibitors (genistein and PP2) allowed a higher level of bacterial multiplication. These observations may help to explain the susceptibility of elders to tuberculosis. An unexpected result was that both genistein and its negative control, daidzein, abundant soy isoflavones, promoted intracellular mycobacterial growth.
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Affiliation(s)
- José M. Guerra-Laso
- />Servicio de Medicina Interna, Hospital de León, Altos de Nava s/n, 24008 León, Spain
| | - Sandra González-García
- />Unidad de Investigación, Hospital de León, Edif. S. Antonio Abad, Altos de Nava s/n, 24008 León, Spain
| | - Carolina González-Cortés
- />Unidad de Investigación, Hospital de León, Edif. S. Antonio Abad, Altos de Nava s/n, 24008 León, Spain
| | - Cristina Diez-Tascón
- />Servicio de Anatomía Patológica, Hospital de León, Altos de Nava s/n, 24008 León, Spain
| | - Ramiro López-Medrano
- />Servicio de Microbiología, Hospital Comarcal del Bierzo, Médicos sin Fronteras, 7, 24411 Fuentesnuevas, Spain
| | - Octavio M. Rivero-Lezcano
- />Unidad de Investigación, Hospital de León, Edif. S. Antonio Abad, Altos de Nava s/n, 24008 León, Spain
- />Fundación Instituto de Estudios de Ciencias de la Salud de Castilla y León, Parque de Santa Clara s/n, 42002 Soria, Spain
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12
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Pacheco SA, Powers KM, Engelmann F, Messaoudi I, Purdy GE. Autophagic Killing Effects against Mycobacterium tuberculosis by Alveolar Macrophages from Young and Aged Rhesus Macaques. PLoS One 2013; 8:e66985. [PMID: 23825603 PMCID: PMC3688994 DOI: 10.1371/journal.pone.0066985] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 05/11/2013] [Indexed: 11/18/2022] Open
Abstract
Non-human primates, notably rhesus macaques (Macaca mulatta, RM), provide a robust experimental model to investigate the immune response to and effective control of Mycobacterium tuberculosis infections. Changes in the function of immune cells and immunosenescence may contribute to the increased susceptibility of the elderly to tuberculosis. The goal of this study was to examine the impact of age on M. tuberculosis host-pathogen interactions following infection of primary alveolar macrophages derived from young and aged rhesus macaques. Of specific interest to us was whether the mycobactericidal capacity of autophagic macrophages was reduced in older animals since decreased autophagosome formation and autophagolysosomal fusion has been observed in other cells types of aged animals. Our data demonstrate that alveolar macrophages from old RM are as competent as those from young animals for autophagic clearance of M. tuberculosis infection and controlling mycobacterial replication. While our data do not reveal significant differences between alveolar macrophage responses to M. tuberculosis by young and old animals, these studies are the first to functionally characterize autophagic clearance of M. tuberculosis by alveolar macrophages from RM.
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Affiliation(s)
- Sophia A Pacheco
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, Oregon, United States of America
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Age-related defects in TLR2 signaling diminish the cytokine response by alveolar macrophages during murine pneumococcal pneumonia. Exp Gerontol 2012; 47:507-18. [PMID: 22548913 DOI: 10.1016/j.exger.2012.04.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 04/12/2012] [Accepted: 04/16/2012] [Indexed: 01/09/2023]
Abstract
Alveolar macrophages (AMs) are the first immune cells to respond to an invading pathogen and coordinate the inflammatory response within the lungs. Studies suggest that macrophages exhibit age-related deficiencies in Toll-like receptor (TLR) function; however, the impact of this dysfunction during pneumonia, the leading cause of infectious death in the elderly, and the underlying mechanisms responsible remain unclear. We examined disease severity in young, mature, and aged BALB/cBy mice following intratracheal infection with the Gram-positive bacteria Streptococcus pneumoniae (Spn). Both mature and aged mice failed to clear bacteria and as a result had increased mortality, tissue damage and vascular leakage. Early production of TNFα, IL-1β, and IL-6 during pneumonia declined with age and was associated with an inability of isolated AMs to respond to pneumococcal cell wall (CW) and ethanol-killed Spn ex vivo. Total levels of TLR1 were unaffected by age and TLR2 surface expression was slightly yet significantly increased on aged AMs suggesting that intracellular TLR signaling defects were responsible for the age-related decline in cytokine responsiveness. Following infection of isolated AMs with live Spn, a significant age-related decline in TLR2-induced phosphorylation of p65 NFκB, JNK and p38 MAPK, and an increase in ERK phosphorylation was observed by immunoblotting. These data are the first to demonstrate that TLR2-dependent recognition of Spn by aged AMs is impaired and is associated with a delayed pro-inflammatory cytokine response in vivo along with enhanced susceptibility to pneumococcal pneumonia.
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Boyd AR, Orihuela CJ. Dysregulated inflammation as a risk factor for pneumonia in the elderly. Aging Dis 2011; 2:487-500. [PMID: 22288022 PMCID: PMC3265328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 07/12/2011] [Accepted: 07/12/2011] [Indexed: 05/31/2023] Open
Abstract
Advances in modern medicine have led to an increase in the median life span and an expansion of the world's population over the age of 65. With increasing numbers of the population surviving to the extreme of age, those at risk for the development of pneumonia will approach 2 billion by the year 2050. Numerous age-related changes in the lung likely contribute to the enhanced occurrence of pneumonia in the elderly. Inflammation in the elderly has been shown to increase risk prior to infection; age-associated inflammation enhances bacterial ligand expression in the lungs which increases the ability of bacteria to attach and invade host cells. Conversely, the elaboration of the acute inflammatory response during early infection has been found to decrease with age resulting in a delayed immune response and diminished bacterial killing. Finally, the resolution of the inflammatory response during the convalescent stage back to "baseline" is often prolonged in the elderly and associated with negative outcomes, such as adverse cardiac events. The focus of this review will be to discuss our current understanding of the potential mechanisms by which dysregulated inflammation (both prior to and following an infectious insult) enhances susceptibility to and severity of community acquired pneumonia (CAP) in the elderly with an emphasis on pneumococcal pneumonia, the leading cause of CAP.
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Affiliation(s)
- Angela R. Boyd
- Department of Microbiology and Immunology, the University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229-3900 USA
| | - Carlos J. Orihuela
- Department of Microbiology and Immunology, the University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229-3900 USA
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15
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Michailidis G, Theodoridis A, Avdi M. Effects of sexual maturation and Salmonella infection on the expression of Toll-like receptors in the chicken vagina. Anim Reprod Sci 2011; 123:234-41. [DOI: 10.1016/j.anireprosci.2011.01.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 12/02/2010] [Accepted: 01/04/2011] [Indexed: 12/21/2022]
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