scholarly journals The Lung Mucosa Environment in the Elderly Increases Host Susceptibility to Mycobacterium tuberculosis Infection

2019 ◽  
Vol 220 (3) ◽  
pp. 514-523 ◽  
Author(s):  
Juan I Moliva ◽  
Michael A Duncan ◽  
Angélica Olmo-Fontánez ◽  
Anwari Akhter ◽  
Eusondia Arnett ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
The Elderly ◽  
Surfactant Protein ◽  
Host Susceptibility ◽  
Surfactant Protein D ◽  
Mycobacterium Tuberculosis Infection ◽  
Increased Risk ◽  
The Impact

AbstractAs we age, there is an increased risk for the development of tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) infection. Few studies consider that age-associated changes in the alveolar lining fluid (ALF) may increase susceptibility by altering soluble mediators of innate immunity. We assessed the impact of adult or elderly human ALF during Mtb infection in vitro and in vivo. We identified amplification of pro-oxidative and proinflammatory pathways in elderly ALF and decreased binding capability of surfactant-associated surfactant protein A (SP-A) and surfactant protein D (SP-D) to Mtb. Human macrophages infected with elderly ALF–exposed Mtb had reduced control and fewer phagosome–lysosome fusion events, which was reversed when elderly ALF was replenished with functional SP-A/SP-D. In vivo, exposure to elderly ALF exacerbated Mtb infection in young mice. Our studies demonstrate how the pulmonary environment changes as we age and suggest that Mtb may benefit from declining host defenses in the lung mucosa of the elderly.

scholarly journals Surfactant Protein D Facilitates Cryptococcus neoformans Infection

2012 ◽  
Vol 80 (7) ◽  
pp. 2444-2453 ◽  
Author(s):  
Scarlett Geunes-Boyer ◽  
Michael F. Beers ◽  
John R. Perfect ◽  
Joseph Heitman ◽  
Jo Rae Wright
Keyword(s):  
Fungal Infection ◽  
Cryptococcus Neoformans ◽  
Defense Mechanisms ◽  
Surfactant Protein ◽  
Host Susceptibility ◽  
Yeast Cells ◽  
Surfactant Protein D ◽  
Content Type

ABSTRACTConcurrent with the global escalation of the AIDS pandemic, cryptococcal infections are increasing and are of significant medical importance. Furthermore,Cryptococcus neoformanshas become a primary human pathogen, causing infection in seemingly healthy individuals. Although numerous studies have elucidated the virulence properties ofC. neoformans, less is understood regarding lung host immune factors during early stages of fungal infection. Based on our previous studies documenting that pulmonary surfactant protein D (SP-D) protectsC. neoformanscells against macrophage-mediated defense mechanismsin vitro(S. Geunes-Boyer et al., Infect. Immun. 77:2783–2794, 2009), we postulated that SP-D would facilitate fungal infectionin vivo. To test this hypothesis, we examined the role of SP-D in response toC. neoformansusing SP-D−/−mice. Here, we demonstrate that mice lacking SP-D were partially protected duringC. neoformansinfection; they displayed a longer mean time to death and decreased fungal burden at several time points postinfection than wild-type mice. This effect was reversed by the administration of exogenous SP-D. Furthermore, we show that SP-D bound to the surface of the yeast cells and protected the pathogenic microbes against macrophage-mediated defense mechanisms and hydrogen peroxide (H2O2)-induced oxidative stressin vitroandin vivo. These findings indicate thatC. neoformansis capable of coopting host SP-D to increase host susceptibility to the yeast. This study establishes a new paradigm for the role played by SP-D during host responses toC. neoformansand consequently imparts insight into potential future preventive and/or treatment strategies for cryptococcosis.

scholarly journals Active vitamin D (1,25-dihydroxyvitamin D3) increases host susceptibility toCitrobacter rodentiumby suppressing mucosal Th17 responses

2012 ◽  
Vol 303 (12) ◽  
pp. G1299-G1311 ◽  
Author(s):  
Natasha R. Ryz ◽  
Scott J. Patterson ◽  
Yiqun Zhang ◽  
Caixia Ma ◽  
Tina Huang ◽  
...  
Keyword(s):  
Vitamin D ◽  
Immune Responses ◽  
Bacterial Pathogen ◽  
Enteric Bacteria ◽  
Host Susceptibility ◽  
Active Vitamin ◽  
Active Vitamin D ◽  
Increased Risk ◽  
The Impact

Vitamin D deficiency affects more that 1 billion people worldwide and is associated with an increased risk of developing a number of inflammatory/autoimmune diseases, including inflammatory bowel disease (IBD). At present, the basis for the impact of vitamin D on IBD and mucosal immune responses is unclear; however, IBD is known to reflect exaggerated immune responses to luminal bacteria, and vitamin D has been shown to play a role in regulating bacteria-host interactions. Therefore, to test the effect of active vitamin D on host responses to enteric bacteria, we gave 1,25(OH)2D3to mice infected with the bacterial pathogen Citrobacter rodentium, an extracellular microbe that causes acute colitis characterized by a strong Th1/Th17 immune response. 1,25(OH)2D3treatment of infected mice led to increased pathogen burdens and exaggerated tissue pathology. In association with their increased susceptibility, 1,25(OH)2D3-treated mice showed substantially reduced numbers of Th17 T cells within their infected colons, whereas only modest differences were noted in Th1 and Treg numbers. In accordance with the impaired Th17 responses, 1,25(OH)2D3-treated mice showed defects in their production of the antimicrobial peptide REG3γ. Taken together, these studies show that 1,25(OH)2D3suppresses Th17 T-cell responses in vivo and impairs mucosal host defense against an enteric bacterial pathogen.

A switch toward angiostatic gene expression impairs the angiogenic properties of endothelial progenitor cells in low birth weight preterm infants

Blood ◽  
2011 ◽  
Vol 118 (6) ◽  
pp. 1699-1709 ◽  
Author(s):  
Isabelle Ligi ◽  
Stéphanie Simoncini ◽  
Edwige Tellier ◽  
Paula Frizera Vassallo ◽  
Florence Sabatier ◽  
...  
Keyword(s):  
Birth Weight ◽  
Low Birth Weight ◽  
Profile Analysis ◽  
Preterm Neonates ◽  
Akt Phosphorylation ◽  
Protein Levels ◽  
Increased Risk ◽  
The Impact

Abstract Low birth weight (LBW) is associated with increased risk of cardiovascular diseases at adulthood. Nevertheless, the impact of LBW on the endothelium is not clearly established. We investigate whether LBW alters the angiogenic properties of cord blood endothelial colony forming cells (LBW-ECFCs) in 25 preterm neonates compared with 25 term neonates (CT-ECFCs). We observed that LBW decreased the number of colonies formed by ECFCs and delayed the time of appearance of their clonal progeny. LBW dramatically reduced LBW-ECFC capacity to form sprouts and tubes, to migrate and to proliferate in vitro. The angiogenic defect of LBW-ECFCs was confirmed in vivo by their inability to form robust capillary networks in Matrigel plugs injected in nu/nu mice. Gene profile analysis of LBW-ECFCs demonstrated an increased expression of antiangiogenic genes. Among them, thrombospondin 1 (THBS1) was highly expressed at RNA and protein levels in LBW-ECFCs. Silencing THBS1 restored the angiogenic properties of LBW-ECFCs by increasing AKT phosphorylation. The imbalance toward an angiostatic state provide a mechanistic link between LBW and the impaired angiogenic properties of ECFCs and allows the identification of THBS1 as a novel player in LBW-ECFC defect, opening new perspectives for novel deprogramming agents.

scholarly journals Aging predisposes to acute inflammatory induced pathology after tumor immunotherapy

2013 ◽  
Vol 210 (11) ◽  
pp. 2223-2237 ◽  
Author(s):  
Myriam N. Bouchlaka ◽  
Gail D. Sckisel ◽  
Mingyi Chen ◽  
Annie Mirsoian ◽  
Anthony E. Zamora ◽  
...  
Keyword(s):  
Critical Role ◽  
The Elderly ◽  
Mouse Tumor ◽  
Aged Mice ◽  
Liver Histopathology ◽  
Multiple Organs ◽  
The Impact ◽  
Young Mice

Cancer commonly occurs in the elderly and immunotherapy (IT) is being increasingly applied to this population. However, the majority of preclinical mouse tumor models assessing potential efficacy and toxicities of therapeutics use young mice. We assessed the impact of age on responses to systemic immune stimulation. In contrast to young mice, systemic cancer IT regimens or LPS given to aged mice resulted in rapid and lethal toxicities affecting multiple organs correlating with heightened proinflammatory cytokines systemically and within the parenchymal tissues. This inflammatory response and increased morbidity with age was independent of T cells or NK cells. However, prior in vivo depletion of macrophages in aged mice resulted in lesser cytokine levels, increased survival, and decreased liver histopathology. Furthermore, macrophages from aged mice and normal human elderly volunteers displayed heightened TNF and IL-6 production upon in vitro stimulation. Treatment of both TNF knockout mice and in vivo TNF blockade in aged mice resulted in significant increases in survival and lessened pathology. Importantly, TNF blockade in tumor-bearing, aged mice receiving IT displayed significant anti-tumor effects. These data demonstrate the critical role of macrophages in the age-associated hyper-inflammatory cytokine responses to systemic immunostimulation and underscore the importance of performing preclinical assessments in aged mice.

scholarly journals Surfactant Protein D Increases Phagocytosis of Hypocapsular Cryptococcus neoformans by Murine Macrophages and Enhances Fungal Survival

2009 ◽  
Vol 77 (7) ◽  
pp. 2783-2794 ◽  
Author(s):  
Scarlett Geunes-Boyer ◽  
Timothy N. Oliver ◽  
Guilhem Janbon ◽  
Jennifer K. Lodge ◽  
Joseph Heitman ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Defense Mechanisms ◽  
Protein A ◽  
Surfactant Protein ◽  
Immune Defense ◽  
Surfactant Protein D ◽  
Wild Type ◽  
Phagocytic Cells

ABSTRACT Cryptococcus neoformans is a facultative intracellular opportunistic pathogen and the leading cause of fungal meningitis in humans. In the absence of a protective cellular immune response, the inhalation of C. neoformans cells or spores results in pulmonary infection. C. neoformans cells produce a polysaccharide capsule composed predominantly of glucuronoxylomannan, which constitutes approximately 90% of the capsular material. In the lungs, surfactant protein A (SP-A) and SP-D contribute to immune defense by facilitating the aggregation, uptake, and killing of many microorganisms by phagocytic cells. We hypothesized that SP-D plays a role in C. neoformans pathogenesis by binding to and enhancing the phagocytosis of the yeast. Here, the abilities of SP-D to bind to and facilitate the phagocytosis and survival of the wild-type encapsulated strain H99 and the cap59Δ mutant hypocapsular strain are assessed. SP-D binding to cap59Δ mutant cells was approximately sixfold greater than binding to wild-type cells. SP-D enhanced the phagocytosis of cap59Δ cells by approximately fourfold in vitro. To investigate SP-D binding in vivo, SP-D−/− mice were intranasally inoculated with Alexa Fluor 488-labeled cap59Δ or H99 cells. By confocal microscopy, a greater number of phagocytosed C. neoformans cells in wild-type mice than in SP-D−/− mice was observed, consistent with in vitro data. Interestingly, SP-D protected C. neoformans cells against macrophage-mediated defense mechanisms in vitro, as demonstrated by an analysis of fungal viability using a CFU assay. These findings provide evidence that C. neoformans subverts host defense mechanisms involving surfactant, establishing a novel virulence paradigm that may be targeted for therapy.

scholarly journals Variations in Helicobacter pylori Lipopolysaccharide To Evade the Innate Immune Component Surfactant Protein D

2005 ◽  
Vol 73 (11) ◽  
pp. 7677-7686 ◽  
Author(s):  
Wafa Khamri ◽  
Anthony P. Moran ◽  
Mulugeta L. Worku ◽  
Q. Najma Karim ◽  
Marjorie M. Walker ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Gastric Mucosa ◽  
Phase Variation ◽  
Surfactant Protein ◽  
Clinical Isolates ◽  
Surfactant Protein D ◽  
Human Gastric Mucosa ◽  
H Pylori

ABSTRACT Helicobacter pylori is a common and persistent human pathogen of the gastric mucosa. Surfactant protein D (SP-D), a component of innate immunity, is expressed in the human gastric mucosa and is capable of aggregating H. pylori. Wide variation in the SP-D binding affinity to H. pylori has been observed in clinical isolates and laboratory-adapted strains. The aim of this study was to reveal potential mechanisms responsible for evading SP-D binding and establishing persistent infection. An escape variant, J178V, was generated in vitro, and the lipopolysaccharide (LPS) structure of the variant was compared to that of the parental strain, J178. The genetic basis for structural variation was explored by sequencing LPS biosynthesis genes. SP-D binding to clinical isolates was demonstrated by fluorescence-activated cell sorter analyses. Here, we show that H. pylori evades SP-D binding through phase variation in lipopolysaccharide. This phenomenon is linked to changes in the fucosylation of the O chain, which was concomitant with slipped-strand mispairing in a poly(C) tract of the fucosyltransferase A (fucT1) gene. SP-D binding organisms are predominant in mucus in vivo (P = 0.02), suggesting that SP-D facilitates physical elimination. Phase variation to evade SP-D contributes to the persistence of this common gastric pathogen.

scholarly journals Behaviour of Titanium Dioxide Particles in Artificial Body Fluids and Human Blood Plasma

2021 ◽  
Vol 22 (19) ◽  
pp. 10614
Author(s):  
Eva Korábková ◽  
Věra Kašpárková ◽  
Daniela Jasenská ◽  
Dita Moricová ◽  
Eliška Daďová ◽  
...  
Keyword(s):  
Blood Plasma ◽  
Human Blood ◽  
Body Fluids ◽  
Human Blood Plasma ◽  
Tio2 Particles ◽  
Commercial Mixture ◽  
Increased Risk ◽  
The Impact

The growing application of materials containing TiO2 particles has led to an increased risk of human exposure, while a gap in knowledge about the possible adverse effects of TiO2 still exists. In this work, TiO2 particles of rutile, anatase, and their commercial mixture were exposed to various environments, including simulated gastric fluids and human blood plasma (both representing in vivo conditions), and media used in in vitro experiments. Simulated body fluids of different compositions, ionic strengths, and pH were used, and the impact of the absence or presence of chosen enzymes was investigated. The physicochemical properties and agglomeration of TiO2 in these media were determined. The time dependent agglomeration of TiO2 related to the type of TiO2, and mainly to the type and composition of the environment that was observed. The presence of enzymes either prevented or promoted TiO2 agglomeration. TiO2 was also observed to exhibit concentration-dependent cytotoxicity. This knowledge about TiO2 behavior in all the abovementioned environments is critical when TiO2 safety is considered, especially with respect to the significant impact of the presence of proteins and size-related cytotoxicity.

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