scholarly journals Paracoccin overexpression in Paracoccidioides brasiliensis reveals the influence of chitin hydrolysis on fungal virulence and host immune response

2019 ◽  
Author(s):  
Relber Aguiar Gonçales ◽  
Vanessa Cristina Silva Vieira ◽  
Rafael Ricci-Azevedo ◽  
Fabrício Freitas Fernandes ◽  
Sandra Maria de Oliveira Thomaz ◽  
...  
Keyword(s):  
Immune Response ◽  
Host Response ◽  
Paracoccidioides Brasiliensis ◽  
In Vitro Assays ◽  
Significant Advance ◽  
Fungal Virulence ◽  
Tnf Α ◽  
Chitin Hydrolysis ◽  
Yeast Genes

ABSTRACTParacoccidioides brasiliensis and P. lutzii, etiological agents of paracoccidioidomycosis (PCM), develop as mycelia at 25-30 °C and as yeast at 35-37 °C. Only a few Paracoccidioides spp. proteins are well characterized. Thus, we studied paracoccin (PCN) from P. brasiliensis, its role in the fungus biology, and its relationship with the host innate immune cells. Cloning and heterologous expression analysis revealed its lectin, enzymatic, and immunomodulatory properties. Recently, we employed a system based on Agrobacterium tumefaciens-mediated transformation to manipulate P. brasiliensis yeast genes to obtain clones knocked-down for PCN, which after all, are unable to transit from yeast to mycelium forms, causing a mild pulmonary disease. Herein, we generate P. brasiliensis overexpressing PCN (ov-PCN). To date, it was not explored the overexpressing of endogenous components in Paracoccidioides spp. Therefore, we investigate the role of PCN in fungal biology and pathogenesis. Augmented levels of PCN mRNA and protein, and N-acetylglucosaminidase activity confirmed PCN overexpression in ov-PCN of P. brasiliensis yeasts. Interestingly, PCN overexpression did not affect the yeasts’ growth or viability and favored cell separation. The ov-PCN clones transitioned faster to the mycelium form than the wt-PCN yeasts. Concerning infection, while most of mice infected with the wt-yeasts (90%) survive at least until the 70th day, all mice infected with ov-PCN yeasts were already died at the 35th day post-infection. In vitro assays showed that ov-PCN were more susceptible to phagocytosis by macrophages. Finally, it was verified that the chitin particles isolated from the ov-PCN cells were smaller than those obtained from the wt-PCN yeasts. Macrophages stimulated with the chitin isolated from ov-PCN produce IL-10, whereas the particles with a wider size range harvested from wt-PCN yeasts induced TNF-α and IL-1β secretion. The anti-inflammatory microenvironment from macrophage stimulation with small chitin particles hampers the development of a protective immune response against the fungus. We postulated that the high grade of chitin cleavage, as the results of augmented PCN expression, favors pathogenesis following P. brasiliensis infection. Thus, PCN is a relevant virulence fungal factor.AUTHOR SUMMARYParacoccidioides spp. are pathogenic fungi that cause paracoccidioidomycosis (PCM) in humans, the main deep mycosis of Latin America. Recently, by knocking down the paracoccin gene, our group showed that this lectin is necessary for the morphological transition from yeast to hyphae, and that this decrease results in low P. brasiliensis virulence. Here, after overexpress PCN, we revealed the importance of the yeast chitin hydrolysis to the host response. Infection of mice with ov-PCN yeasts causes severe lung disease compared to moderate disease caused by wt-PCN yeasts. The release of smaller chitin particles was as a result of an accelerated chitin hydrolysis provided by ov-PCN yeasts. Interestingly, these smallest chitin particles are able to modulate host response by increasing IL-10 in the meantime that decrease TNF-α secretion, thus hampering Th1 immune response that is crucial in the fight against this fungi. These findings represent a significant advance in the knowledge about the role of PCN chitinase in P. brasiliensis.

scholarly journals CD69 Deficiency Enhances the Host Response to Vaccinia Virus Infection through Altered NK Cell Homeostasis

2016 ◽  
Vol 90 (14) ◽  
pp. 6464-6474 ◽  
Author(s):  
Laura Notario ◽  
Elisenda Alari-Pahissa ◽  
Antonio de Molina ◽  
Pilar Lauzurica
Keyword(s):  
Immune Response ◽  
Infection Control ◽  
Vaccinia Virus ◽  
Nk Cells ◽  
Natural Killer ◽  
Host Response ◽  
Nk Cell ◽  
Innate Immune ◽  
Cell Numbers

ABSTRACTDuring the host response to viral infection, the transmembrane CD69 protein is highly upregulated in all immune cells. We have studied the role of CD69 in the murine immune response to vaccinia virus (VACV) infection, and we report that the absence of CD69 enhances protection against VACV at both short and long times postinfection in immunocompetent and immunodeficient mice. Natural killer (NK) cells were implicated in the increased infection control, since the differences were greatly diminished when NK cells were depleted. This role of NK cells was not based on an altered NK cell reactivity, since CD69 did not affect the NK cell activation threshold in response to major histocompatibility complex class I NK cell targets or protein kinase C activation. Instead, NK cell numbers were increased in the spleen and peritoneum of CD69-deficient infected mice. That was not just secondary to better infection control in CD69-deficient mice, since NK cell numbers in the spleens and the blood of uninfected CD69−/−mice were already augmented. CD69-deficient NK cells from infected mice did not have an altered proliferation capacity. However, a lower spontaneous cell death rate was observed for CD69−/−lymphocytes. Thus, our results suggest that CD69 limits the innate immune response to VACV infection at least in part through cell homeostatic survival.IMPORTANCEWe show that increased natural killer (NK) cell numbers augment the host response and survival after infection with vaccinia virus. This phenotype is found in the absence of CD69 in immunocompetent and immunodeficient hosts. As part of the innate immune system, NK lymphocytes are activated and participate in the defense against infection. Several studies have focused on the contribution of NK cells to protection against infection with vaccinia virus. In this study, it was demonstrated that the augmented early NK cell response in the absence of CD69 is responsible for the increased protection seen during infection with vaccinia virus even at late times of infection. This work indicates that the CD69 molecule may be a target of therapy to augment the response to poxvirus infection.

scholarly journals Depletion of Neutrophils Exacerbates the Early Inflammatory Immune Response in Lungs of Mice Infected withParacoccidioides brasiliensis

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Paula Andrea Pino-Tamayo ◽  
Juan David Puerta-Arias ◽  
Damaris Lopera ◽  
Martha Eugenia Urán-Jiménez ◽  
Ángel González
Keyword(s):  
Monoclonal Antibody ◽  
Immune Response ◽  
Inflammatory Response ◽  
Paracoccidioides Brasiliensis ◽  
Yeast Cells ◽  
Histopathological Analysis ◽  
Acute Inflammatory Response ◽  
Fungal Load ◽  
Inflammatory Immune Response

Neutrophils predominate during the acute phase of theParacoccidioides brasiliensisinfection. Herein, we determined the role of the neutrophil during the early stages of experimental pulmonary paracoccidioidomycosis using a monoclonal antibody (mAb) specific for neutrophils. Male BALB/c mice were inoculated intranasally with1.5×106or2×106P. brasiliensisyeast cells. The mAb was administered 24 h before infection, followed by doses every 48 h until mice were sacrificed. Survival time was evaluated and mice were sacrificed at 48 h and 96 h after inoculation to assess cellularity, fungal load, cytokine/chemokine levels, and histopathological analysis. Neutrophils from mAb-treated mice were efficiently depleted (99.04%). Eighty percent of the mice treated with the mAb and infected with1.5×106yeast cells died during the first two weeks after infection. When mice were treated and infected with2×106yeast cells, 100% of them succumbed by the first week after infection. During the acute inflammatory response significant increases in numbers of eosinophils, fungal load and levels of proinflammatory cytokines/chemokines were observed in the mAb-treated mice. We also confirmed that neutrophils are an important source of IFN-γand IL-17. These results indicate that neutrophils are essential for protection as well as being important for regulating the early inflammatory immune response in experimental pulmonary paracoccidioidomycosis.

scholarly journals Significant and conflicting correlation of IL-9 with Prevotella and Bacteroides in human colorectal cancer

2020 ◽  
Author(s):  
E Niccolai ◽  
E Russo ◽  
S Baldi ◽  
F Ricci ◽  
G Nannini ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Immune Response ◽  
Multinomial Regression ◽  
Tnf Α ◽  
Ifn Γ ◽  
Inflammatory Profile ◽  
Infiltrating Lymphocytes ◽  
First Time

ABSTRACTBackgroundColorectal cancer (CRC) is a widespread disease that represents an example of chronic inflammation-associated tumor. In fact, the immune system, besides protecting the host from developing tumors, can support the CRC progression. In this scenario, the gut microbiota (GM) is essential to modulate immune responses and a dysbiotic condition can favor chronic/abnormal immune activation that support the tumor growth. GM can elicit the production of cytokines, influencing the immunostimulatory or immunosuppressive reactions, such as the tendency to mount Th1, Th17, Tregs or Th9 responses that play different roles towards colon cancer. Paradigmatic is the role of IL-9 that can both promote tumor progression in hematological malignancies and inhibit tumorigenesis in solid cancers. Therefore, to investigate the microbiota-immunity axis in CRC patients is crucial to well understand the cancer development with positive relapses in prevention and treatment.AimThe cellular and molecular characterization of the immune response and the evaluation of GM composition in healthy and tumor mucosa, focusing on the correlation between cytokines’ profile and GM signature.MethodsWe collected tumoral (CRC) and healthy (CRC-S) mucosa samples of 45 CRC patients. For each sample, we characterized the Tissue Infiltrating Lymphocytes (TIL)’s subset profile and the GM composition. In addition, in 14 CRC patients, we evaluated the CRC and CRC-S molecular inflammatory response (26 cytokines/chemokines) and we correlated this profile with GM composition using the Dirichlet Multinomial Regression.ResultsThe analysis of T cells subsets distribution showed that CRC samples displayed higher percentages of Th17, Th2, Tregs, Tc17, Tc1/Tc17, and Tcreg, compared to CRC-S. Notably, also the number of Th9 was higher, even if not significantly, in CRC tissue compared to healthy one. In addition, we found that MIP-1α, IL-1β, IL-2, IP-10, IL-6, IL-8, IL-17A, IFN-γ, TNF-α, MCP-1, IL-1α, P-selectin and IL-9 were significantly increased in CRC compared to CRC-S. Moreover, the GM analysis revealed that CRC samples had significantly higher levels of Fusobacteria, Proteobacteria, Fusobacterium, Ruminococcus2 (Lachnospiraceae family) and Ruminococcus (Ruminococcaceae family) than CRC-S. Finally, we found that the abundance of Prevotella spp in CRC samples was negatively correlated with IL-17A and positively with IL-9. In addition, the abundance of Bacteroides and Escherichia/Shigella species in CRC samples showed a negative association with IL-9 and IP-10 respectively.ConclusionsOur data show a clear dissimilarity of inflammatory profile and GM composition between the tumor and the adjacent healthy tissue, displaying the generation of a peculiar CRC microenvironment. Interestingly, relating the tissue cytokine profile with the GM composition, we confirmed the presence of a bidirectional crosstalk between the immune response and the host’s commensal microorganisms; in detail, we documented for the first time that Prevotella spp. and Bacteroides spp. are correlated (positively and negatively, respectively) with the IL-9, whose role in CRC development is still debated.

scholarly journals Lipophilicity of Bacteriochlorin-Based Photosensitizers as a Determinant for PDT Optimization through the Modulation of the Inflammatory Mediators

2019 ◽  
Vol 9 (1) ◽  
pp. 8 ◽  
Author(s):  
Barbara Pucelik ◽  
Luis G. Arnaut ◽  
Janusz M. Dąbrowski
Keyword(s):  
Immune Response ◽  
Molecular Mechanisms ◽  
Near Infrared ◽  
Antitumor Immune Response ◽  
Infrared Light ◽  
Gm Csf ◽  
Hydrophobic Compound ◽  
Tnf Α ◽  
Wide Range

Photodynamic therapy (PDT) augments the host antitumor immune response, but the role of the PDT effect on the tumor microenvironment in dependence on the type of photosensitizer and/or therapeutic protocols has not been clearly elucidated. We employed three bacteriochlorins (F2BOH, F2BMet and Cl2BHep) of different polarity that absorb near-infrared light (NIR) and generated a large amount of reactive oxygen species (ROS) to compare the PDT efficacy after various drug-to-light intervals: 15 min. (V-PDT), 3h (E-PDT) and 72h (C-PDT). We also performed the analysis of the molecular mechanisms of PDT crucial for the generation of the long-lasting antitumor immune response. PDT-induced damage affected the integrity of the host tissue and developed acute (protocol-dependent) local inflammation, which in turn led to the infiltration of neutrophils and macrophages. In order to further confirm this hypothesis, a number of proteins in the plasma of PDT-treated mice were identified. Among a wide range of cytokines (IL-6, IL-10, IL-13, IL-15, TNF-α, GM-CSF), chemokines (KC, MCP-1, MIP1α, MIP1β, MIP2) and growth factors (VEGF) released after PDT, an important role was assigned to IL-6. PDT protocols optimized for studied bacteriochlorins led to a significant increase in the survival rate of BALB/c mice bearing CT26 tumors, but each photosensitizer (PS) was more or less potent, depending on the applied DLI (15 min, 3 h or 72 h). Hydrophilic (F2BOH) and amphiphilic (F2BMet) PSs were equally effective in V-PDT (>80 cure rate). F2BMet was the most efficient in E-PDT (DLI = 3h), leading to a cure of 65 % of the animals. Finally, the most powerful PS in the C-PDT (DLI = 72 h) regimen turned out to be the most hydrophobic compound (Cl2BHep), allowing 100 % of treated animals to be cured at a light dose of only 45 J/cm2.

scholarly journals Differential Involvement of Toll-Like Receptors 2 and 4 in the Host Response to Acute Respiratory Infections with Wild-Type and Mutant Haemophilus influenzae Strains

2005 ◽  
Vol 73 (4) ◽  
pp. 2075-2082 ◽  
Author(s):  
Eva Lorenz ◽  
Diana C. Chemotti ◽  
Alice L. Jiang ◽  
Letitia D. McDougal
Keyword(s):  
Haemophilus Influenzae ◽  
Host Response ◽  
Respiratory Infections ◽  
Acute Respiratory Infections ◽  
Bacterial Clearance ◽  
Wild Type ◽  
Tlr2 Expression ◽  
Neutrophil Influx ◽  
Tnf Α

ABSTRACT We used a mouse model of acute respiratory infections to investigate the role of Toll-like receptor 2 (TLR2) and TLR4 in the host response to Haemophilus influenzae. Acute aerosol exposures to wild-type strains of H. influenzae showed that TLR4 function was essential for TNF-α induction, neutrophil influx, and bacterial clearance. To determine how lipooligosaccharide (LOS) modifications would affect the role of TLR4 in inducing the host response, we used acute infections with an H. influenzae strain expressing a mutation in the htrB gene. This mutant strain expresses an LOS subunit with decreased acylation. In response to H. influenzae htrB infection, tumor necrosis factor alpha (TNF-α) secretion remained TLR4 dependent. But the decrease in LOS acylation made the neutrophil influx and the bacterial clearance also dependent on TLR2, as shown by the decreased host response elicited in TLR2 knockout mice compared to C57BL/6 mice. A subsequent analysis of TLR2 and TLR4 gene expression by quantitative PCR indicated that TLR4 function induces TLR2 expression and vice versa. These results indicate that some changes in the LOS subunit of H. influenzae can favor signaling through non-TLR4 receptors, such as TLR2. The results also indicate a close interaction between TLR4 and TLR2 that tightly regulates the expression of both receptors.

scholarly journals Adaptive stress response induced by toluene increasesSporothrix schenckiivirulence and host immune response

2019 ◽  
Author(s):  
Damiana Téllez-Martínez ◽  
Alexander Batista-Duharte ◽  
Vinicius Paschoalini Silva ◽  
Deivys Portuondo Fuentes ◽  
Lucas Souza Ferreira ◽  
...  
Keyword(s):  
Immune Response ◽  
Stress Response ◽  
Sporothrix Schenckii ◽  
Host Immune Response ◽  
Peritoneal Macrophages ◽  
Fungal Virulence ◽  
Functional Changes ◽  
Tnf Α ◽  
Intraperitoneal Infection ◽  
Adaptive Stress Response

ABSTRACTEnvironmental factors modify the physiology of microorganisms, allowing their survival in extreme conditions. However, the influence of chemical contaminants on fungal virulence has been little studied. Sporotrichosis is an emergent fungal disease caused bySporothrix schenckii,a soil-inhabiting fungus that has been found in polluted environments. Here, we evaluated the adaptive stress response ofS. schenckiiinduced by toluene, a key soil contaminant. The effect on fungal virulence and host immune response was also assessed. The fungus survived up to 0.10% toluene in liquid medium. Greater production of melanosomes and enhanced activity superoxide dismutase, associated to increased tolerance to H2O2were observed in toluene-exposed fungi. Intraperitoneal infection of mice withS. schenckiitreated with either 0, 0.01 or 0.1% of toluene, resulted in greater fungal burden at day 7 post-infection in spleen and liver in the groups infected with fungus treated with toluene 0.1%. A higher production of Il-1β, TNF-α, IL-10 and nitric oxyde by peritoneal macrophages and IFNγ, IL-4 and IL-17 by splenocytes was also observed in that group. Our findings showed that morphological and functional changes induced by toluene leads to increasedS. schenckiivirulence and antifungal host immune response in our model.

scholarly journals Role of Circulating Lymphocytes in Patients with Sepsis

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Raul de Pablo ◽  
Jorge Monserrat ◽  
Alfredo Prieto ◽  
Melchor Alvarez-Mon
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Host Response ◽  
Adaptive Immune Response ◽  
Adaptive Immune ◽  
Potential Biomarker ◽  
Circulating Lymphocytes ◽  
Postmortem Studies

Sepsis is a systemic inflammatory response syndrome due to infection. The incidence rate is estimated to be up to 19 million cases worldwide per year and the number of cases is rising. Infection triggers a complex and prolonged host response, in which both the innate and adaptive immune response are involved. The disturbance of immune system cells plays a key role in the induction of abnormal levels of immunoregulatory molecules. Furthermore, the involvement of effector immune system cells also impairs the host response to the infective agents and tissue damage. Recently, postmortem studies of patients who died of sepsis have provided important insights into why septic patients die and showed an extensive depletion of CD4 and CD8 lymphocytes and they found that circulating blood cells showed similar findings. Thus, the knowledge of the characterization of circulating lymphocyte abnormalities is relevant for the understanding of the sepsis pathophysiology. In addition, monitoring the immune response in sepsis, including circulating lymphocyte subsets count, appears to be potential biomarker for predicting the clinical outcome of the patient. This paper analyzes the lymphocyte involvement and dysfunction found in patients with sepsis and new opportunities to prevent sepsis and guide therapeutic intervention have been revealed.

scholarly journals THE ROLE OF CYTOKINES TNF-Α, IFN-Γ, IL-1, IL-4, IL-8 IN THE IMMUNE RESPONSE IN INFECTIOUS LESIONS OF CNS IN CHILDREN

2018 ◽  
Vol 17 (1) ◽  
pp. 17-22 ◽  
Author(s):  
S. N. Eshmolov ◽  
I. G. Sitnikov ◽  
I. M. Melnikova
Keyword(s):  
Immune Response ◽  
Tnf Α ◽  
Ifn Γ

scholarly journals Endogenous Interleukin-12 Is Not Required for Resolution of Chlamydophila abortus (Chlamydia psittaci Serotype 1) Infection in Mice

2001 ◽  
Vol 69 (8) ◽  
pp. 4808-4815 ◽  
Author(s):  
Laura Del Rı́o ◽  
Antonio J. Buendı́a ◽  
Joaquı́n Sánchez ◽  
Marı́a C. Gallego ◽  
Marı́a R. Caro ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Host Response ◽  
Chlamydia Psittaci ◽  
Sublethal Dose ◽  
Interleukin 12 ◽  
Chlamydophila Abortus ◽  
Ifn Γ ◽  
Th1 Immune Response

ABSTRACT A Th1 immune response involving gamma interferon (IFN-γ) production is required to eliminate Chlamydophila abortusinfections. In this study, the role of interleukin-12 (IL-12) in protecting against C. abortus infection was investigated using IL-12−/− and wild-type (WT) C57BL/6 mice to determine the role of this Th1-promoting cytokine. IL-12−/− mice were able to eliminate the C. abortus infection in a primary infection. However, there was a delay in the clearance of bacteria when IL-12−/− mice were infected with a sublethal dose of C. abortus, the delay being associated with a lower production of IFN-γ. The low level of IFN-γ was essential for survival of IL-12−/−infected mice. Both WT and IL-12−/− mice developed a Th1 immune response against C. abortus infection, since they both produced IFN-γ and immunoglobulin G2a antibody isotype. In addition, when mice were given a secondary infectious challenge withC. abortus, a protective host response which resolved the secondary infection was developed by both WT and IL-12−/−mice. The lack of IL-12 resulted in few infiltrating CD4+ T cells in the liver relative to the number in WT mice, although the number of CD8+ T cells was slightly higher. The more intense Th1 response presented by WT mice may have a pathogenic effect, as the animals showed higher morbidity after the infection. In conclusion, these results suggest that although IL-12 expedites the clearance of C. abortus infection, this cytokine is not essential for the establishment of a protective host response against the infection.

scholarly journals Virulence Vs. Immunomodulation: Roles of the Paracoccin Chitinase and Carbohydrate-Binding Sites in Paracoccidioides brasiliensis Infection

2021 ◽  
Vol 8 ◽  
Author(s):  
Nayla de Souza Pitangui ◽  
Fabrício Freitas Fernandes ◽  
Relber Aguiar Gonçales ◽  
Maria Cristina Roque-Barreira
Keyword(s):  
Cell Wall ◽  
Host Response ◽  
Paracoccidioides Brasiliensis ◽  
Severe Disease ◽  
Chitinase Activity ◽  
Carbohydrate Binding ◽  
Toll Like Receptor ◽  
Dimorphic Fungus ◽  
Fungal Virulence ◽  
Yeast Infection

Paracoccin (PCN) is a bifunctional protein primarily present in the cell wall of Paracoccidioides brasiliensis, a human pathogenic dimorphic fungus. PCN has one chitinase region and four potential lectin sites and acts as both a fungal virulence factor and an immunomodulator of the host response. The PCN activity on fungal virulence, mediated by the chitinase site, was discovered by infecting mice with yeast overexpressing PCN (PCN-ov). PCN-ov are characterized by increased chitin hydrolysis, a narrow cell wall, and augmented resistance to phagocytes' fungicidal activity. Compared to wild-type (wt) yeast, infection with PCN-ov yeast causes a more severe disease, which is attributed to the increased PCN chitinase activity. In turn, immunomodulation of the host response was demonstrated by injecting, subcutaneously, recombinant PCN in mice infected with wt-P. brasiliensis. Through its carbohydrate binding site, the injected recombinant PCN interacts with Toll-like receptor 2 (TLR2) and Toll-like receptor 4 (TLR4) N-glycans on macrophages, triggers M1 polarization, and stimulates protective Th1 immunity against the fungus. The PCN-treatment of wt yeast-infected mice results in mild paracoccidioidomycosis. Therefore, PCN paradoxically influences the course of murine paracoccidioidomycosis. The disease is severe when caused by yeast that overexpress endogenous PCN, which exerts a robust local chitinase activity, followed by architectural changes of the cell wall and release of low size chito-oligomers. However, the disease is mild when exogenous PCN is injected, which recognizes N-glycans on systemic macrophages resulting in immunomodulation.

Sign in / Sign up

Export Citation Format

Share Document