scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Pulmonary cryptococcosis induces chitinase in the rat.

15 May 2008-Respiratory Research (BioMed Central)-Vol. 9, Iss: 1, pp 40-40
TL;DR: A possible link between respiratory fungal infections, including C. neoformans, and asthma through the induction of AMCase is indicated through the induced chitinase activity within the lung and bronchoalveolar lavage fluid of infected rats.
Abstract: Background: We previously demonstrated that chronic pulmonary infection with Cryptococcus neoformans results in enhanced allergic inflammation and airway hyperreactivity in a rat model. Because the cell wall of C. neoformans consists of chitin, and since acidic mammalian chitinase (AMCase) has recently been implicated as a novel mediator of asthma, we sought to determine whether such infection induces chitinase activity and expression of AMCase in the rat. Methods: We utilized a previously-established model of chronic C. neoformans pulmonary infection in the rat to analyze the activity, expression and localization of AMCase. Results: Our studies indicate that intratracheal inoculation of C. neoformans induces chitinase activity within the lung and bronchoalveolar lavage fluid of infected rats. Chitinase activity is also elicited by pulmonary infection with other fungi (e.g. C. albicans), but not by the inoculation of dead organisms. Enhanced chitinase activity reflects increased AMCase expression by airway epithelial cells and alveolar macrophages. Systemic cryptococcosis is not associated with increased pulmonary chitinase activity or AMCase expression. Conclusion: Our findings indicate a possible link between respiratory fungal infections, including C. neoformans, and asthma through the induction of AMCase.

Content maybe subject to copyright    Report

Citations
More filters
Journal ArticleDOI
TL;DR: The object of this study are chitinolytic enzymes produced by bacterium Clostridium paraputrificum J4 isolated from the gastrointestinal tract of a healthy human, and the development of purification protocols, determination of properties of the enzymes and their activity profiles.
Abstract: The object of this study are chitinolytic enzymes produced by bacterium Clostridium paraputrificum J4 isolated from the gastrointestinal tract of a healthy human. In particular, we focus on the development of purification protocols, determination of properties of the enzymes and their activity profiles. The process of bacteria cultivation and isolation of chitinolytic complex of enzymes showing specific activities of endo-, exo-chitinase and N-acetyl-β-glucosaminidase was optimized. A range of various purification procedures were used such as ultrafiltration, precipitation, chromatographic separations (ion-exchange, size exclusion, chromatofocusing) in altered combinations. The optimal purification protocol comprises two or three steps. Individual samples were analyzed by SDS/PAGE electrophoresis and after renaturation their activity could be detected using zymograms. Mass spectroscopy peptide fragment analysis and MALDI analysis of the purest samples indicate presence of endochitinase B (molecular mass about 85 kDa) and of 60-kDa endo- and exochitinases.

12 citations


Cites background from "Pulmonary cryptococcosis induces ch..."

  • ...The presence of bacterial chitinases in human colon can play an important role as part of defence mechanisms against fungal invasion (Vicencio et al., 2008)....

    [...]

Journal ArticleDOI
TL;DR: A high diversity in the pathogenic potential of isolates of C. gattii belonging to the molecular types VGIII and VGIV is demonstrated, reflected in differential pathogenicity.
Abstract: Cryptococcus gattii is one of the causative agents of human cryptococcosis. Highly virulent strains of serotype B C. gattii have been studied in detail, but little information is available on the pathogenic properties of serotype C isolates. In this study, we analyzed pathogenic determinants in three serotype C C. gattii isolates (106.97, ATCC 24066 and WM 779). Isolate ATCC 24066 (molecular type VGIII) differed from isolates WM 779 and 106.97 (both VGIV) in capsule dimensions, expression of CAP genes, chitooligomer distribution, and induction of host chitinase activity. Isolate WM 779 was more efficient than the others in producing pigments and all three isolates had distinct patterns of reactivity with antibodies to glucuronoxylomannan. This great phenotypic diversity reflected in differential pathogenicity. VGIV isolates WM 779 and 106.97 were similar in their ability to cause lethality and produced higher pulmonary fungal burden in a murine model of cryptococcosis, while isolate ATCC 24066 (VGIII) was unable to reach the brain and caused reduced lethality in intranasally infected mice. These results demonstrate a high diversity in the pathogenic potential of isolates of C. gattii belonging to the molecular types VGIII and VGIV.

12 citations

Journal ArticleDOI
TL;DR: Evidence supporting a chitin biosynthetic pathway in Pneumocystis organisms and that chit inases modulate inflammatory responses in lung cells is provided.
Abstract: Pneumocystis pneumonia remains an important complication of immune suppression. The cell wall of Pneumocystis has been demonstrated to potently stimulate host inflammatory responses, with most studies focusing on β-glucan components of the Pneumocystis cell wall. In the current study, we have elaborated the potential role of chitins and chitinases in Pneumocystis pneumonia. We demonstrated differential host mammalian chitinase expression during Pneumocystis pneumonia. We further characterized a chitin synthase gene in Pneumocystis carinii termed Pcchs5, a gene with considerable homolog to the fungal chitin biosynthesis protein Chs5. We also observed the impact of chitinase digestion on Pneumocystis-induced host inflammatory responses by measuring TNFα release and mammalian chitinase expression by cultured lung epithelial and macrophage cells stimulated with Pneumocystis cell wall isolates in the presence and absence of exogenous chitinase digestion. These findings provide evidence supporting a chitin biosynthetic pathway in Pneumocystis organisms and that chitinases modulate inflammatory responses in lung cells. We further demonstrate lung expression of chitinase molecules during Pneumocystis pneumonia.

11 citations


Cites background from "Pulmonary cryptococcosis induces ch..."

  • ...In addition, the immunological roles of host mammalian chitinases have also recently been evaluated in various inflammatory disease models including asthma or allergen challenge with ovalbumin, Th2- and IL13-mediated inflammation, cigarette smoke challenge models, and pulmonary cryptococcosis [38, 39]....

    [...]

Journal ArticleDOI
TL;DR: The results suggest that MMV1593537 is a promising, nontoxic fungicide whose mechanism of action, at least in Cryptococcus spp, requires chitinase-mediated hydrolysis of Chitin, a structure which is essential for fungal life.
Abstract: The development of novel antifungals is a matter of urgency. In this study, we evaluated antifungal activities in a collection of 400 molecules, using highly lethal fungal pathogens as targets. ABSTRACT There is an urgent unmet need for novel antifungals. In this study, we searched for novel antifungal activities in the Pandemic Response Box, a collection of 400 structurally diverse compounds in various phases of drug discovery. We identified five molecules which could control the growth of Cryptococcus neoformans, Cryptococcus deuterogattii, and the emerging global threat Candida auris. After eliminating compounds which demonstrated paradoxical antifungal effects or toxicity to mammalian macrophages, we selected compound MMV1593537 as a nontoxic, fungicidal molecule for further characterization of antifungal activity. Scanning electron microscopy revealed that MMV1593537 affected cellular division in all three pathogens. In Cryptococcus, MMV1593537 caused a reduction in capsular dimensions. Treatment with MMV1593537 resulted in increased detection of cell wall chitooligomers in these three species. Since chitooligomers are products of the enzymatic hydrolysis of chitin, we investigated whether surface chitinase activity was altered in response to MMV1593537 exposure. We observed peaks of enzyme activity in C. neoformans and C. deuterogattii in response to MMV1593537. We did not detect any surface chitinase activity in C. auris. Our results suggest that MMV1593537 is a promising, nontoxic fungicide whose mechanism of action, at least in Cryptococcus spp, requires chitinase-mediated hydrolysis of chitin. IMPORTANCE The development of novel antifungals is a matter of urgency. In this study, we evaluated antifungal activities in a collection of 400 molecules, using highly lethal fungal pathogens as targets. One of these molecules, namely, MMV1593537, was not toxic to host cells and controlled the growth of isolates of Cryptococcus neoformans, C. deuterogattii, C. gattii, Candida auris, C. albicans, C. parapsilosis, and C. krusei. We tested the mechanisms of antifungal action of MMV1593537 in the Cryptococcus and C. auris models and concluded that the compound affects the cell wall, a structure which is essential for fungal life. At least in Cryptococcus, this effect involved chitinase, an enzyme which is required for remodeling the cell wall. Our results suggest that MMV1593537 is a candidate for future antifungal development.

10 citations

Journal ArticleDOI
TL;DR: This study presents a first time report of Chitinase producing Bacillus cereus from the gut of catfish (Clarias gariepinus) which can be employed for the biocontrol of fungal pathogens and harmful insects.
Abstract: Chitinases are hydrolytic enzymes that break down the glycosidic bonds in chitin. Chitin is a component of the cell walls of fungi and exoskeletal elements of some animals (including worms and arthropods), therefore, chitinases are generally found in organisms that either needs to reshape their own chitin or dissolve and digest the chitin of fungi or animals. The importance of chitinase in industries cannot be overemphasized as it has been applied in agriculture, as a biopesticide for control of plant fungi infections, in medicine, as indicators of fungi infection and in waste management, for biodegradation of fish waste. African catfish (Clarias gariepinus) which plays host to bacteria is very readily available and easy to cultivate thus providing a cheap means of obtaining chitinolytic bacteria for the production of chitinase in commercial quantity. Bacteria populations isolated from the skin and gut of catfish were screened on colloidal-chitin agar medium. Chitinase production was determined by zones of hydrolysis produced after 96 h of incubation at 37EC. The result of this investigation revealed thirty-six pure bacterial isolates from the skin and gut of catfish. Gram staining test revealed, twenty five Gram positive bacteria while eleven were Gram negative. After four days of incubation, twenty-six bacteria isolates obtained from the gut and skin of catfish were selected as chitinase producing bacteria based on the clear zones of hydrolysis produced. The bacterial isolates obtained will be very useful for the production of chitinase which can be employed for the biocontrol of fungal pathogens and harmful insects. This study presents a first time report of Chitinase producing Bacillus cereus from the gut of catfish (Clarias gariepinus).

10 citations


Cites background from "Pulmonary cryptococcosis induces ch..."

  • ...Similarly, six chitinases from Bacillus circulans WL-12 were reported by Watanabe et al. (1992) Members of the genus Bacillus are well known for their potential to secrete a number of degradative enzymes such as chitinases (Schallmey et al., 2004)....

    [...]

References
More filters
Journal ArticleDOI
11 Jun 2004-Science
TL;DR: It is shown that acidic mammalian chitinase (AMCase) is induced via a T helper-2 (Th2)–specific, interleukin-13 (IL-13)–mediated pathway in epithelial cells and macrophages in an aeroallergen asthma model and expressed in exaggerated quantities in human asthma.
Abstract: Chitin is a surface component of parasites and insects, and chitinases are induced in lower life forms during infections with these agents. Although chitin itself does not exist in humans, chitinases are present in the human genome. We show here that acidic mammalian chitinase (AMCase) is induced via a T helper-2 (Th2)-specific, interleukin-13 (IL-13)-mediated pathway in epithelial cells and macrophages in an aeroallergen asthma model and expressed in exaggerated quantities in human asthma. AMCase neutralization ameliorated Th2 inflammation and airway hyperresponsiveness, in part by inhibiting IL-13 pathway activation and chemokine induction. AMCase may thus be an important mediator of IL-13-induced responses in Th2-dominated disorders such as asthma.

795 citations


"Pulmonary cryptococcosis induces ch..." refers background or methods or result in this paper

  • ...Acidic mammalian chitinase (AMCase) has emerged as an important mediator of allergic asthma in both animal models and in humans [5-7]....

    [...]

  • ...Evidence from their laboratory demonstrates that over-expression of IL-13 induces endogenous AMCase activity and results in airway hyperreactivity [5], and that blockage of AMCase activity attenuates the response....

    [...]

  • ...that increased AMCase expression in airway epithelial cells and alveolar macrophages parallels generalized chitinase activity and is consistent with previous investigations [5,13]....

    [...]

  • ...Chitinase activity assay was performed utilizing an established protocol [5]....

    [...]

Journal ArticleDOI
TL;DR: YKL-40 is found in increased quantities in the serum and lungs in a subgroup of patients with asthma, in whom expression of chitinase in both compartments correlates with the severity of asthma.
Abstract: Background The evolutionarily conserved 18-glycosyl-hydrolase family contains true chitinases and chitinase-like proteins that lack enzymatic activity. Acidic mammalian chitinase has recently been associated with animal models of asthma. The related chitinase-like protein, YKL-40 (also called human cartilage glycoprotein 39 [HCgp-39] and chitinase 3–like 1), can be readily measured in the serum. However, its relationship to asthma has not been evaluated. Methods We quantified serum YKL-40 levels in three cohorts of patients with asthma — one recruited from the patient population at Yale University, one from the University of Paris, and one from the University of Wisconsin — as well as in controls from the surrounding communities. In the Paris cohort, immunohistochemical analysis and morphometric quantitation were used to evaluate the locus of expression of YKL-40 in the lung. The clinical characteristics of the patients with high serum or lung YKL-40 levels were also evaluated. Results Serum YKL-40 levels...

525 citations


"Pulmonary cryptococcosis induces ch..." refers background in this paper

  • ...Importantly, additional proteins with chitinase activity have also been discovered in both rodents and humans, including BRP-39 (mouse), YKL-40 (human) and chitotriosidase [17]....

    [...]

Journal ArticleDOI
TL;DR: The study has revealed the existence of a chitinolytic enzyme in the gastrointestinal tract and lung that may play a role in digestion and/or defense.

489 citations


"Pulmonary cryptococcosis induces ch..." refers methods in this paper

  • ...Reactivity at 50 kDa, the approximate molecular weight of AMCase, was used to indicate AMCase expression [9]....

    [...]

Journal ArticleDOI
TL;DR: The results suggest that the low incidence of symptomatic cryptococcal disease in children with AIDS is not a result of lack of exposure to C neoformans, and provide both indirect and direct evidence of C neo formans infection in immunocompetent children.
Abstract: Objective. Cryptococcus neoformans is an important cause of central nervous system infection in adults with acquired immunodeficiency syndrome (AIDS) but an unusual cause of disease in children with AIDS. The basis for this age-related difference in incidence is not known but may be caused by differences in exposure or immune response. The objective of this study was to determine whether the low prevalence of cryptococcal disease among children is related to a lack of exposure to C neoformans . Methods. Sera were obtained from 185 immunocompetent individuals ranging in age from 1 week to 21 years who were being evaluated in an urban emergency department. Sera were analyzed for antibodies to C neoformans and Candida albicans proteins by immunoblotting. Immunoblot patterns were compared with those obtained from sera of patients with cryptococcosis ( n = 10) and workers in a laboratory devoted to the study of C neoformans . The specificity of our results was confirmed by several approaches, including antibody absorption and blocking studies. Sera were also analyzed for the presence of cryptococcal polysaccharide by both enzyme-linked immunosorbent assay and latex agglutination assays. Results. Sera from children 1.1 to 2 years old demonstrated minimal reactivity to C neoformans proteins. In contrast, the majority of sera from children >2 years old recognized many (≥6) C neoformans proteins. For children between 2.1 and 5 years old, 56% of sera ( n = 25) reacted with many proteins, whereas for children >5 years old ( n = 120), 70% of samples reacted with many proteins. Reactivity was decreased by absorbing sera with C neoformans extracts or by preincubating blots with sera from experimentally infected but not from control rats. Reactivity to C neoformans proteins did not correlate with reactivity to C albicans proteins, which was common in sera from children between the ages of 1.1 and 2 years. Cryptococcal polysaccharide was detected at a titer of 1:16 (∼10 ng/mL) in the sera of 1 child, a 5.6-year-old boy who presented to the emergency department with vomiting. Conclusions. Our findings provide both indirect and direct evidence of C neoformans infection in immunocompetent children. Our results indicate that C neoformans infects a majority of children living in the Bronx after 2 years old. These results are consistent with several observations: the ubiquitous nature of C neoformans in the environment, including its association with pigeon excreta; the large number of pigeons in urban areas; and the increased likelihood of environmental exposure for children once they have learned to walk. The signs and symptoms associated with C neoformans infection in immunocompetent children remained to be determined. Primary pulmonary cryptococcosis may be asymptomatic or produce symptoms confused with viral infections and, therefore, not recognized as a fungal infection. Our results suggest that the low incidence of symptomatic cryptococcal disease in children with AIDS is not a result of lack of exposure to C neoformans . These findings have important implications for C neoformans pathogenesis and the development of vaccine strategies.

382 citations


"Pulmonary cryptococcosis induces ch..." refers background in this paper

  • ...neoformans infection is common among Bronx children, a cohort with an extraordinarily high rate of asthma, suggesting a potential role for this type of infection in asthma pathogenesis [4]....

    [...]

Journal ArticleDOI
TL;DR: Despite widespread exposure to household allergens, the strongest relationship between exposure and sensitization was seen in the bedroom and suggested that exposure to low doses of allergen, 2 U/g or less, was a risk factor and that the risk plateaus above 4 U/G.
Abstract: Background: It is important to understand the relationship between environmental allergen exposure dose and the risk of atopic individuals becoming sensitized to that allergen if we are to change the risk of sensitization and morbidity from allergic disease Objective: The objective of these studies was to determine whether there was a dose response between current exposure to mite, cockroach, and cat allergen in inner-city children and to determine the prevalence of sensitization to these allergens Methods: A sample of 500 children was selected from the 1528 children enrolled in the National Cooperative Inner City Asthma Study Children were selected who had a sample of home dust and valid skin test responses performed with a MultiTest skin test device The samples of home dust were collected from the floor and furniture in the kitchen, bedroom, and television/living room and were assayed for Der p 1, Der f 1, Bla g 1, and Fel d 1 allergens Results: Each allergen level correlated significantly between rooms in individual homes Mite (Der p 1 and Der f 1) and cat (Fel d 1) allergen levels were frequently below the detection limit of the assay Cockroach allergen (Bla g 1) concentrations in the child's bedroom were related to the prevalence of positive skin test responses to cockroach allergen extract among the children, with an odds ratio for sensitization of 145 (111-192) Positive skin test responses to cockroach allergen were seen in 15% of children exposed to bedroom dust with a Bla g 1 concentration below the level of detection compared with a rate of 32% in bedrooms with Bla g 1 levels of 1 to 2 U/g and 40% to 44% among those in rooms with 4 U/g or greater The relationship between exposure and positive skin test responses was clearly stronger among atopic children with a greater number of positive skin test responses Conclusions: Despite widespread exposure to household allergens, the strongest relationship between exposure and sensitization was seen in the bedroom The dose response between exposure to cockroach allergen and sensitization suggested that exposure to low doses of allergen, 2 U/g or less, was a risk factor and that the risk plateaus above 4 U/g Atopy modified the relationship of exposure to sensitization (J Allergy Clin Immunol 1998;102:563-70)

328 citations


"Pulmonary cryptococcosis induces ch..." refers background in this paper

  • ...We also note that chitin is also major constituent of other exposures that have been linked with urban asthma including cockroaches [19]....

    [...]