scholarly journals Toll-Like Receptor 9 Modulates Immune Responses to Aspergillus fumigatus Conidia in Immunodeficient and Allergic Mice

2008 ◽  
Vol 77 (1) ◽  
pp. 108-119 ◽  
Author(s):  
Hemanth Ramaprakash ◽  
Toshihiro Ito ◽  
Theodore J. Standiford ◽  
Steven L. Kunkel ◽  
Cory M. Hogaboam
Keyword(s):  
Immune Responses ◽  
Aspergillus Fumigatus ◽  
Inflammatory Responses ◽  
Fungal Growth ◽  
Lower Airway ◽  
Interleukin 17 ◽  
Toll Like Receptor ◽  
Wild Type ◽  
Immunodeficient Mice

ABSTRACT The role of Toll-like receptor 9 (TLR9) in antifungal responses in the immunodeficient and allergic host is unclear. We investigated the role of TLR9 in murine models of invasive aspergillosis and fungal asthma. Neutrophil-depleted TLR9 wild-type (TLR9+/+) and TLR9-deficient (TLR9−/−) mice were challenged with resting or swollen Aspergillus fumigatus conidia and monitored for survival and lung inflammatory responses. The absence of TLR9 delayed, but did not prevent, mortality in immunodeficient mice challenged with resting or swollen conidia compared to TLR9+/+ mice. In a fungal asthma model, TLR9+/+ and TLR9−/− mice were sensitized to soluble A. fumigatus antigens and challenged with resting or swollen A. fumigatus conidia, and both groups of mice were analyzed prior to and at days 7, 14, and 28 after the conidium challenge. When challenged with resting conidia, TLR9−/− mice exhibited significantly lower airway hyper-responsiveness compared to the TLR9+/+ groups. In contrast, A. fumigatus-sensitized TLR9−/− mice exhibited pulmonary fungal growth at days 14 and 28 after challenge with swollen conidia, a finding never observed in their allergic wild-type counterparts. Increased fungal growth in allergic TLR9−/− mice correlated with markedly decreased dectin-1 expression in whole lung samples and isolated dendritic cell populations. Further, whole lung levels of interleukin-17 were lower in allergic TLR9−/− mice compared to similar TLR9+/+ mice. Together, these data suggest that TLR9 modulates pulmonary antifungal immune responses to swollen conidia, possibly through the regulation of dectin-1 expression.

scholarly journals Cytadherence of Mycoplasma pneumoniae Induces Inflammatory Responses through Autophagy and Toll-Like Receptor 4

2014 ◽  
Vol 82 (7) ◽  
pp. 3076-3086 ◽  
Author(s):  
Takashi Shimizu ◽  
Yui Kimura ◽  
Yutaka Kida ◽  
Koichi Kuwano ◽  
Masato Tachibana ◽  
...  
Keyword(s):  
Immune Responses ◽  
Mycoplasma Pneumoniae ◽  
Cytokine Production ◽  
Inflammatory Responses ◽  
Hypothetical Protein ◽  
Toll Like Receptor ◽  
Wild Type ◽  
Toll Like Receptor 4 ◽  
Content Type ◽  
Toll Like Receptor 2

ABSTRACTMycoplasma pneumoniaecauses pneumonia, tracheobronchitis, pharyngitis, and asthma in humans. The pathogenesis ofM. pneumoniaeinfection is attributed to excessive immune responses. We previously demonstrated thatM. pneumoniaelipoproteins induced inflammatory responses through Toll-like receptor 2 (TLR2). In the present study, we demonstrated thatM. pneumoniaeinduced strong inflammatory responses in macrophages derived from TLR2 knockout (KO) mice. Cytokine production in TLR2 KO macrophages was increased compared with that in the macrophages of wild-type (WT) mice. Heat-killed, antibiotic-treated, and overgrownM. pneumoniaefailed to induce inflammatory responses in TLR2 KO macrophages. 3-Methyladenine and chloroquine, inhibitors of autophagy, decreased the induction of inflammatory responses in TLR2 KO macrophages. These inflammatory responses were also inhibited in macrophages treated with the TLR4 inhibitor VIPER and those obtained from TLR2 and TLR4 (TLR2/4) double-KO mice. Two mutants that lacked the ability to induce inflammatory responses in TLR2 KO macrophages were obtained by transposon mutagenesis. The transposons were inserted inatpCencoding an ATP synthase F0F1 ε subunit andF10_orf750encoding hypothetical protein MPN333. These mutants showed deficiencies in cytadherence. These results suggest that cytadherence ofM. pneumoniaeinduces inflammatory responses through TLR4 and autophagy.

scholarly journals Role of TLR4 Receptor Polymorphisms in Boutonneuse Fever

2005 ◽  
Vol 18 (4) ◽  
pp. 655-660 ◽  
Author(s):  
C.R. Balistreri ◽  
G. Candore ◽  
D. Lio ◽  
G. Colonna-Romano ◽  
G. Di Lorenzo ◽  
...  
Keyword(s):  
Immune Responses ◽  
Genetic Background ◽  
Inflammatory Responses ◽  
Advanced Age ◽  
Toll Like Receptor ◽  
Boutonneuse Fever ◽  
Receptor Signalling ◽  
The Individual ◽  
Tlr4 Receptor

The genetics of the interaction between host and microbes plays an essential role in the survival of the individual and attainment of longevity. The activation of toll-like receptor (TLR)4 plays a key role in natural and clonotypic immune responses. We evaluated whether TLR4 genotype is a component of genetic background protective versus rickettsiosis and whether this background influences longevity. We genotyped for +896A/G TLR4 polymorphism 78 patients affected by Boutonneuse fever, 78 age-matched controls and 78 advanced age individuals from Sicily. The +869G allele, that attenuates receptor signalling, was significantly overrepresented in patients in comparison with age-matched controls. By analyzing data according to gender, this allele was significantly higher in female patients when compared to advanced age women. Pro-inflammatory responses are programmed to resist fatal infections. So, it is not surprising that the genetic background of people that survive to an advanced age may be protective against infections. However, this seems to occur in women but not in men. In a previous study, the +896G TLR4 allele was overrepresented in advanced age men and underrepresented in men affected by myocardial infarction. Thus, previous and present results tend to agree with the suggestion that men and women may follow different trajectories to reach longevity. For men it might be more important to control atherogenesis, whereas for women it might be more important to control infectious diseases.

scholarly journals Essential role of IRAK-4 protein and its kinase activity in Toll-like receptor–mediated immune responses but not in TCR signaling

2007 ◽  
Vol 204 (5) ◽  
pp. 1013-1024 ◽  
Author(s):  
Tatsukata Kawagoe ◽  
Shintaro Sato ◽  
Andreas Jung ◽  
Masahiro Yamamoto ◽  
Kosuke Matsui ◽  
...  
Keyword(s):  
Immune Responses ◽  
Kinase Activity ◽  
Interleukin 1 ◽  
Cell Receptor ◽  
Nuclear Factor Κb ◽  
Toll Like Receptor ◽  
Tcr Signaling ◽  
Mitogen Activated Protein

Interleukin-1 receptor–associated kinase 4 (IRAK-4) was reported to be essential for the Toll-like receptor (TLR)– and T cell receptor (TCR)–mediated signaling leading to the activation of nuclear factor κB (NF-κB). However, the importance of kinase activity of IRAK family members is unclear. In this study, we investigated the functional role of IRAK-4 activity in vivo by generating mice carrying a knockin mutation (KK213AA) that abrogates its kinase activity. IRAK-4KN/KN mice were highly resistant to TLR-induced shock response. The cytokine production in response to TLR ligands was severely impaired in IRAK-4KN/KN as well as IRAK-4−/− macrophages. The IRAK-4 activity was essential for the activation of signaling pathways leading to mitogen-activated protein kinases. TLR-induced IRAK-4/IRAK-1–dependent and –independent pathways were involved in early induction of NF-κB–regulated genes in response to TLR ligands such as tumor necrosis factor α and IκBζ. In contrast to a previous paper (Suzuki, N., S. Suzuki, D.G. Millar, M. Unno, H. Hara, T. Calzascia, S. Yamasaki, T. Yokosuka, N.J. Chen, A.R. Elford, et al. 2006. Science. 311:1927–1932), the TCR signaling was not impaired in IRAK-4−/− and IRAK-4KN/KN mice. Thus, the kinase activity of IRAK-4 is essential for the regulation of TLR-mediated innate immune responses.

scholarly journals The Role of Src Kinase in Macrophage-Mediated Inflammatory Responses

2012 ◽  
Vol 2012 ◽  
pp. 1-18 ◽  
Author(s):  
Se Eun Byeon ◽  
Young-Su Yi ◽  
Jueun Oh ◽  
Byong Chul Yoo ◽  
Sungyoul Hong ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Immune Responses ◽  
Inflammatory Responses ◽  
Inflammatory Diseases ◽  
Src Kinase ◽  
Multiple Roles ◽  
Cellular Migration ◽  
Pharmaceutical Drugs ◽  
Tyrosine Protein Kinase

Src kinase (Src) is a tyrosine protein kinase that regulates cellular metabolism, survival, and proliferation. Many studies have shown that Src plays multiple roles in macrophage-mediated innate immunity, such as phagocytosis, the production of inflammatory cytokines/mediators, and the induction of cellular migration, which strongly implies that Src plays a pivotal role in the functional activation of macrophages. Macrophages are involved in a variety of immune responses and in inflammatory diseases including rheumatoid arthritis, atherosclerosis, diabetes, obesity, cancer, and osteoporosis. Previous studies have suggested roles for Src in macrophage-mediated inflammatory responses; however, recently, new functions for Src have been reported, implying that Src functions in macrophage-mediated inflammatory responses that have not been described. In this paper, we discuss recent studies regarding a number of these newly defined functions of Src in macrophage-mediated inflammatory responses. Moreover, we discuss the feasibility of Src as a target for the development of new pharmaceutical drugs to treat macrophage-mediated inflammatory diseases. We provide insights into recent reports regarding new functions for Src that are related to macrophage-related inflammatory responses and the development of novel Src inhibitors with strong immunosuppressive and anti-inflammatory properties, which could be applied to various macrophage-mediated inflammatory diseases.

scholarly journals Calcineurin Controls Growth, Morphology, and Pathogenicity in Aspergillus fumigatus

2006 ◽  
Vol 5 (7) ◽  
pp. 1091-1103 ◽  
Author(s):  
William J. Steinbach ◽  
Robert A. Cramer ◽  
B. Zachary Perfect ◽  
Yohannes G. Asfaw ◽  
Theodor C. Sauer ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Clinical Observation ◽  
Immunocompromised Patient ◽  
Fungal Growth ◽  
Pathogenic Fungi ◽  
Wild Type ◽  
Therapeutic Approaches ◽  
Growth Morphology ◽  
Different Types ◽  
Hyphal Morphology

ABSTRACT Calcineurin is implicated in a myriad of human diseases as well as homeostasis and virulence in several major human pathogenic microorganisms. The fungus Aspergillus fumigatus is a leading cause of infectious death in the rapidly expanding immunocompromised patient population. Current antifungal treatments for invasive aspergillosis are often ineffective, and novel therapeutic approaches are urgently needed. We demonstrate that a mutant of A. fumigatus lacking the calcineurin A (cnaA) catalytic subunit exhibited defective hyphal morphology related to apical extension and polarized growth, which resulted in drastically decreased filamentation. The ΔcnaA mutant lacked the extensive lattice of invading hyphae seen with the wild-type and complemented strains. Sporulation was also affected in the ΔcnaA mutant, including morphological conidial defects with the absence of surface rodlets and the added presence of disjunctors creating long conidial chains. Infection with the ΔcnaA mutant in several distinct animal models with different types of immunosuppression and inoculum delivery led to a profound attenuation of pathogenicity compared to infection with the wild-type and complemented strains. Lung tissue from animals infected with the ΔcnaA mutant showed a complete absence of hyphae, in contrast to tissue from animals infected with the wild-type and complemented strains. Quantitative fungal burden and pulmonary infarct scoring confirmed these findings. Our results support the clinical observation that substantially decreasing fungal growth can prevent disease establishment and decrease mortality. Our findings reveal that calcineurin appears to play a globally conserved role in the virulence of several pathogenic fungi and yet plays specialized roles in each and can be an excellent target for therapeutic intervention.

Social Stressors, Arboviral Infection, and Immune Dysregulation in the Coastal Lowland Region of Ecuador: A Mixed Methods Approach in Ecological Perspective

2021 ◽  
Author(s):  
Denisse Vega Ocasio ◽  
Anna M. Stewart-Ibarra ◽  
Rachel Sippy ◽  
Christina Li ◽  
Kaitlyn McCue ◽  
...  
Keyword(s):  
At Risk ◽  
Immune Responses ◽  
Inflammatory Responses ◽  
Social Stressors ◽  
Biological Responses ◽  
Distress Symptoms ◽  
Tnf Α ◽  
Hair Samples ◽  
Arboviral Diseases

Aedes aegypti, the mosquito that transmits arboviral diseases such as dengue (DENV), chikungunya (CHIKV), and Zika viruses (ZIKV), is present in tropical and subtropical regions of the world. Individuals at risk of mosquito-borne disease (MBD) in the urban tropics face daily challenges linked to their socio-environment conditions, such as poor infrastructure, poverty, crowding, and limited access to adequate healthcare. These daily demands induce chronic stress events and dysregulated immune responses. We sought to investigate the role of socio-ecologic risk factors in distress symptoms and their impact on biological responses to MBD in Machala, Ecuador. Between 2017 and 2019, individuals (≥ 18 years) with suspected arbovirus illness (DENV, ZIKV, and CHIKV) from sentinel clinics were enrolled (index cases, N = 28). Cluster investigations of the index case households and people from four houses within a 200-m radius of index home (associate cases, N = 144) were conducted (total N = 172). Hair samples were collected to measure hair cortisol concentration (HCC) as a stress biomarker. Blood samples were collected to measure serum cytokines concentrations of IL-10, IL-8, TNF-α, and TGF-β. Univariate analyses were used to determine the association of socio-health metrics related to perceived stress scores (PSS), HCC, and immune responses. We found that housing conditions influence PSS and HCC levels in individuals at risk of MBD. Inflammatory cytokine distribution was associated with the restorative phase of immune responses in individuals with low-moderate HCC. These data suggest that cortisol may dampen pro-inflammatory responses and influence activation of the restorative phase of immune responses to arboviral infections.

scholarly journals Immunosuppressive Mechanisms of Regulatory B Cells

2021 ◽  
Vol 12 ◽  
Author(s):  
Diego Catalán ◽  
Miguel Andrés Mansilla ◽  
Ashley Ferrier ◽  
Lilian Soto ◽  
Kristine Oleinika ◽  
...  
Keyword(s):  
B Cells ◽  
Immune Responses ◽  
Metabolic Diseases ◽  
Inflammatory Responses ◽  
Surface Proteins ◽  
Regulatory B Cells ◽  
Cell Surface Proteins ◽  
The Past ◽  
And Function

Regulatory B cells (Bregs) is a term that encompasses all B cells that act to suppress immune responses. Bregs contribute to the maintenance of tolerance, limiting ongoing immune responses and reestablishing immune homeostasis. The important role of Bregs in restraining the pathology associated with exacerbated inflammatory responses in autoimmunity and graft rejection has been consistently demonstrated, while more recent studies have suggested a role for this population in other immune-related conditions, such as infections, allergy, cancer, and chronic metabolic diseases. Initial studies identified IL-10 as the hallmark of Breg function; nevertheless, the past decade has seen the discovery of other molecules utilized by human and murine B cells to regulate immune responses. This new arsenal includes other anti-inflammatory cytokines such IL-35 and TGF-β, as well as cell surface proteins like CD1d and PD-L1. In this review, we examine the main suppressive mechanisms employed by these novel Breg populations. We also discuss recent evidence that helps to unravel previously unknown aspects of the phenotype, development, activation, and function of IL-10-producing Bregs, incorporating an overview on those questions that remain obscure.

scholarly journals The Role of Vitamin D and Vitamin D Receptor in Immunity toLeishmania majorInfection

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
James P. Whitcomb ◽  
Mary DeAgostino ◽  
Mark Ballentine ◽  
Jun Fu ◽  
Martin Tenniswood ◽  
...  
Keyword(s):  
Vitamin D ◽  
Immune Responses ◽  
Vitamin D Receptor ◽  
Leishmania Major ◽  
Active Form ◽  
Wild Type ◽  
Vitamin D Signaling ◽  
Deficient Mice ◽  
Th 1

Vitamin D signaling modulates a variety of immune responses. Here, we assessed the role of vitamin D in immunity to experimental leishmaniasis infection in vitamin D receptor-deficient mice (VDRKO). We observed that VDRKO mice on a genetically resistant background have decreasedLeishmania major-induced lesion development compared to wild-type (WT) mice; additionally, parasite loads in infected dermis were significantly lower at the height of infection. Enzymatic depletion of the active form of vitamin D mimics the ablation of VDR resulting in an increased resistance toL. major. Conversely, VDRKO or vitamin D-deficient mice on the susceptible Th2-biased background had no change in susceptibility. These studies indicate vitamin D deficiency, either through the ablation of VDR or elimination of its ligand, 1,25D3, leads to an increase resistance toL. majorinfection but only in a host that is predisposed for Th-1 immune responses.

Cellular and molecular insights on the regulation of innate immune responses to experimental aspergillosis in chicken and turkey poults

2020 ◽  
Author(s):  
Tobias Vahsen ◽  
Laura Zapata ◽  
Rodrigo Guabiraba ◽  
Elise Melloul ◽  
Nathalie Cordonnier ◽  
...  
Keyword(s):  
Immune Responses ◽  
Aspergillus Fumigatus ◽  
Inflammatory Responses ◽  
Clinical Signs ◽  
Innate Immune ◽  
Innate Immune Responses ◽  
Lung Lesions ◽  
Turkey Poults ◽  
Cd8 T Lymphocyte ◽  
Fungal Immunity

Abstract Across the world, many commercial poultry flocks and captive birds are threatened by infection with Aspergillus fumigatus. Susceptibility to aspergillosis varies among birds; among galliform birds specifically, morbidity and mortality rates seem to be greater in turkeys than in chickens. Little is known regarding the features of avian immune responses after inhalation of Aspergillus conidia, and to date, scarce information on inflammatory responses during aspergillosis exists. Thus, in the present study, we aimed to improve our understanding of the interactions between A. fumigatus and economically relevant galliform birds in terms of local innate immune responses. Intra-tracheal aerosolization of A. fumigatus conidia in turkey and chicken poults led to more severe clinical signs and lung lesions in turkeys, but leukocyte recovery from lung lavages was higher in chickens at 1dpi only. Interestingly, only chicken CD8+ T lymphocyte proportions increased after infection. Furthermore, the lungs of infected chickens showed an early upregulation of pro-inflammatory cytokines, including IL-1β, IFN-γ and IL-6, whereas in turkeys, most of these cytokines showed a downregulation or a delayed upregulation. These results confirmed the importance of an early pro-inflammatory response to ensure the development of an appropriate anti-fungal immunity to avoid Aspergillus dissemination in the respiratory tract. In conclusion, we show for the first time that differences in local innate immune responses between chickens and turkeys during aspergillosis may determine the outcome of the disease. Lay Summary Aspergillus fumigatus infection may cause mortality in poultry, depending on species sensitivity. This study confirms the earlier activation of chickens’ pro-inflammatory effectors to control Aspergillus dissemination, whereas turkeys’ immune response enables the exacerbation of lung lesions.

scholarly journals Succinate Is an Inflammation-Induced Immunoregulatory Metabolite in Macrophages

Metabolites ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 372 ◽  
Author(s):  
Karl J. Harber ◽  
Kyra E. de Goede ◽  
Sanne G. S. Verberk ◽  
Elisa Meinster ◽  
Helga E. de Vries ◽  
...  
Keyword(s):  
Immune Responses ◽  
Immune Cells ◽  
Immune Cell ◽  
Inflammatory Responses ◽  
Inflammatory Diseases ◽  
Cell Phenotype ◽  
Independent Manner ◽  
Inflammatory Macrophages ◽  
Necrosis Factor

Immunometabolism revealed the crucial role of cellular metabolism in controlling immune cell phenotype and functions. Macrophages, key immune cells that support progression of numerous inflammatory diseases, have been well described as undergoing vast metabolic rewiring upon activation. The immunometabolite succinate particularly gained a lot of attention and emerged as a crucial regulator of macrophage responses and inflammation. Succinate was originally described as a metabolite that supports inflammation via distinct routes. Recently, studies have indicated that succinate and its receptor SUCNR1 can suppress immune responses as well. These apparent contradictory effects might be due to specific experimental settings and particularly the use of distinct succinate forms. We therefore compared the phenotypic and functional effects of distinct succinate forms and receptor mouse models that were previously used for studying succinate immunomodulation. Here, we show that succinate can suppress secretion of inflammatory mediators IL-6, tumor necrosis factor (TNF) and nitric oxide (NO), as well as inhibit Il1b mRNA expression of inflammatory macrophages in a SUCNR1-independent manner. We also observed that macrophage SUCNR1 deficiency led to an enhanced inflammatory response without addition of exogenous succinate. While our study does not reveal new mechanistic insights into how succinate elicits different inflammatory responses, it does indicate that the inflammatory effects of succinate and its receptor SUCNR1 in macrophages are clearly context dependent.

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