Age-related defects in TLR2 signaling diminish the cytokine response by alveolar macrophages during murine pneumococcal pneumonia

Angela R. Boyd, Pooja Shivshankar, Shoulei Jiang, Michael T Berton, Carlos J. Orihuela

Research output: Contribution to journalArticle

56 Citations (Scopus)

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.

Original languageEnglish (US)
Pages (from-to)507-518
Number of pages12
JournalExperimental Gerontology
Volume47
Issue number7
DOIs
StatePublished - Jul 2012

Fingerprint

Pneumococcal Pneumonia
Alveolar Macrophages
Streptococcus pneumoniae
Cytokines
Defects
Phosphorylation
Toll-Like Receptors
Pneumonia
Bacteria
Macrophages
Gram-Positive Bacteria
p38 Mitogen-Activated Protein Kinases
Pathogens
Infection
Interleukin-1
Immunoblotting
Cell Wall
Blood Vessels
Cause of Death
Interleukin-6

Keywords

  • Aging
  • Interleukin-6
  • Macrophages
  • MAPK
  • NFκB
  • Pneumonia
  • Streptococcus pneumoniae
  • Toll-like receptor
  • Tumor necrosis factor α

ASJC Scopus subject areas

  • Aging
  • Biochemistry
  • Cell Biology
  • Endocrinology
  • Genetics
  • Molecular Biology

Cite this

Age-related defects in TLR2 signaling diminish the cytokine response by alveolar macrophages during murine pneumococcal pneumonia. / Boyd, Angela R.; Shivshankar, Pooja; Jiang, Shoulei; Berton, Michael T; Orihuela, Carlos J.

In: Experimental Gerontology, Vol. 47, No. 7, 07.2012, p. 507-518.

Research output: Contribution to journalArticle

Boyd, Angela R. ; Shivshankar, Pooja ; Jiang, Shoulei ; Berton, Michael T ; Orihuela, Carlos J. / Age-related defects in TLR2 signaling diminish the cytokine response by alveolar macrophages during murine pneumococcal pneumonia. In: Experimental Gerontology. 2012 ; Vol. 47, No. 7. pp. 507-518.
@article{f257ca8f6dde4134b7ba9856bbb3eac0,
title = "Age-related defects in TLR2 signaling diminish the cytokine response by alveolar macrophages during murine pneumococcal pneumonia",
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.",
keywords = "Aging, Interleukin-6, Macrophages, MAPK, NFκB, Pneumonia, Streptococcus pneumoniae, Toll-like receptor, Tumor necrosis factor α",
author = "Boyd, {Angela R.} and Pooja Shivshankar and Shoulei Jiang and Berton, {Michael T} and Orihuela, {Carlos J.}",
year = "2012",
month = "7",
doi = "10.1016/j.exger.2012.04.004",
language = "English (US)",
volume = "47",
pages = "507--518",
journal = "Experimental Gerontology",
issn = "0531-5565",
publisher = "Elsevier Inc.",
number = "7",

}

TY - JOUR

T1 - Age-related defects in TLR2 signaling diminish the cytokine response by alveolar macrophages during murine pneumococcal pneumonia

AU - Boyd, Angela R.

AU - Shivshankar, Pooja

AU - Jiang, Shoulei

AU - Berton, Michael T

AU - Orihuela, Carlos J.

PY - 2012/7

Y1 - 2012/7

N2 - 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.

AB - 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.

KW - Aging

KW - Interleukin-6

KW - Macrophages

KW - MAPK

KW - NFκB

KW - Pneumonia

KW - Streptococcus pneumoniae

KW - Toll-like receptor

KW - Tumor necrosis factor α

UR - http://www.scopus.com/inward/record.url?scp=84861744885&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84861744885&partnerID=8YFLogxK

U2 - 10.1016/j.exger.2012.04.004

DO - 10.1016/j.exger.2012.04.004

M3 - Article

C2 - 22548913

AN - SCOPUS:84861744885

VL - 47

SP - 507

EP - 518

JO - Experimental Gerontology

JF - Experimental Gerontology

SN - 0531-5565

IS - 7

ER -