scholarly journals In Vitro or In Vivo Models, the Next Frontier for Unraveling Interactions between Malassezia spp. and Hosts. How Much Do We Know?

2020 ◽  
Vol 6 (3) ◽  
pp. 155
Author(s):  
Maritza Torres ◽  
Hans de Cock ◽  
Adriana Marcela Celis Ramírez
Keyword(s):  
Galleria Mellonella ◽  
Fungal Infections ◽  
Model Organisms ◽  
In Vivo Models ◽  
Alternative Models ◽  
Microbe Interactions ◽  
Host Microbe Interactions ◽  
Malassezia Spp

Malassezia is a lipid-dependent genus of yeasts known for being an important part of the skin mycobiota. These yeasts have been associated with the development of skin disorders and cataloged as a causal agent of systemic infections under specific conditions, making them opportunistic pathogens. Little is known about the host–microbe interactions of Malassezia spp., and unraveling this implies the implementation of infection models. In this mini review, we present different models that have been implemented in fungal infections studies with greater attention to Malassezia spp. infections. These models range from in vitro (cell cultures and ex vivo tissue), to in vivo (murine models, rabbits, guinea pigs, insects, nematodes, and amoebas). We additionally highlight the alternative models that reduce the use of mammals as model organisms, which have been gaining importance in the study of fungal host–microbe interactions. This is due to the fact that these systems have been shown to have reliable results, which correlate with those obtained from mammalian models. Examples of alternative models are Caenorhabditis elegans, Drosophila melanogaster, Tenebrio molitor, and Galleria mellonella. These are invertebrates that have been implemented in the study of Malassezia spp. infections in order to identify differences in virulence between Malassezia species.

scholarly journals In Vitro or in Vivo Models, the Next Frontier for Unraveling Interactions between Malassezia spp. and Hosts. How Much do We Know?

2020 ◽  
Author(s):  
Maritza Torres ◽  
Hans De Cock ◽  
Adriana Marcela Celis Ramírez
Keyword(s):  
Galleria Mellonella ◽  
Fungal Infections ◽  
Ex Vivo ◽  
Model Organisms ◽  
In Vivo Models ◽  
Fungal Host ◽  
Alternative Models ◽  
Malassezia Spp

Malassezia is a lipid-dependent genus of yeasts known for being an important part of the skin mycobiota. These yeasts have been associated in the development of skin disorders and cataloged as a causal agent of systemic infections under specific conditions, making them opportunistic pathogens. Little is known about the host-microbe interaction of Malassezia spp., and unraveling this implies the implementation of infection models. In this mini review we present different models that have been implemented in the fungal infections study with greater attention in Malassezia spp. infections. These models range from in vitro (cell cultures and ex vivo tissue), to in vivo (murine models, rabbits, guinea pigs, insects, nematodes, and amoebas). We additionally highlight the alternative models that reduce the use of mammals as model organisms, which have been gaining importance in the study of fungal host-microbe interactions. This is due to the fact that these systems have shown to have reliable results, which correlate with those obtained from mammalian models. Example of alternative models are Caenorhabditis elegans, Drosophila melanogaster, Tenebrio molitor, and Galleria mellonella. These are invertebrates that have been implemented in the study of Malassezia spp. infections in order to identify differences in virulence between Malassezia species.

scholarly journals Gut organoids: mini-tissues in culture to study intestinal physiology and disease

2019 ◽  
Vol 317 (3) ◽  
pp. C405-C419 ◽  
Author(s):  
Mohammad Almeqdadi ◽  
Miyeko D. Mana ◽  
Jatin Roper ◽  
Ömer H. Yilmaz
Keyword(s):  
Cell Lines ◽  
Three Dimensional ◽  
Gastrointestinal Diseases ◽  
In Vivo Models ◽  
Intestinal Physiology ◽  
Microbe Interactions ◽  
Immortalized Cell ◽  
In Vitro Cell Cultures

In vitro, cell cultures are essential tools in the study of intestinal function and disease. For the past few decades, monolayer cellular cultures, such as cancer cell lines or immortalized cell lines, have been widely applied in gastrointestinal research. Recently, the development of three-dimensional cultures known as organoids has permitted the growth of normal crypt-villus units that recapitulate many aspects of intestinal physiology. Organoid culturing has also been applied to study gastrointestinal diseases, intestinal-microbe interactions, and colorectal cancer. These models are amenable to CRISPR gene editing and drug treatments, including high-throughput small-molecule testing. Three-dimensional intestinal cultures have been transplanted into mice to develop versatile in vivo models of intestinal disease, particularly cancer. Limitations of currently available organoid models include cost and challenges in modeling nonepithelial intestinal cells, such as immune cells and the microbiota. Here, we describe the development of organoid models of intestinal biology and the applications of organoids for study of the pathophysiology of intestinal diseases and cancer.

scholarly journals Virulence of the emerging pathogen, Burkholderia pseudomallei, depends upon the O-linked oligosaccharyltransferase, PglL

2020 ◽  
Vol 15 (4) ◽  
pp. 241-257
Author(s):  
Samuel J Willcocks ◽  
Carmen Denman ◽  
Felipe Cia ◽  
Elizabeth McCarthy ◽  
Jon Cuccui ◽  
...  
Keyword(s):  
Burkholderia Pseudomallei ◽  
Galleria Mellonella ◽  
In Vitro Assays ◽  
In Vivo Models ◽  
Bacterial Fitness ◽  
Isogenic Mutants ◽  
Type Strains ◽  
Broad Role

Aim: We sought to characterize the contribution of the O-OTase, PglL, to virulence in two Burkholderia spp. by comparing isogenic mutants in Burkholderia pseudomallei with the related species, Burkholderia thailandensis. Materials & methods: We utilized an array of in vitro assays in addition to Galleria mellonella and murine in vivo models to assess virulence of the mutant and wild-type strains in each Burkholderia species. Results: We found that pglL contributes to biofilm and twitching motility in both species. PglL uniquely affected morphology; cell invasion; intracellular motility; plaque formation and intergenus competition in B. pseudomallei. This mutant was attenuated in the murine model, and extended survival in a vaccine-challenge experiment. Conclusion: Our data support a broad role for pglL in bacterial fitness and virulence, particularly in B. pseudomallei.

scholarly journals Gut mélange à trois: fluctuating selection modulated by microbiota, host immune system, and antibiotics

2021 ◽  
Author(s):  
Hugo Condessa Barreto ◽  
Beatriz Abreu ◽  
Isabel Gordo
Keyword(s):  
Immune System ◽  
Iron Homeostasis ◽  
Host Immune System ◽  
Iron Availability ◽  
Lipocalin 2 ◽  
Fluctuating Selection ◽  
Microbe Interactions ◽  
Host Microbe Interactions

Iron is critical in host-microbe interactions, and its availability is under tight regulation in the mammalian gut. Antibiotics and inflammation are known to perturb iron availability in the gut, which could subsequently alter host-microbe interactions. Here, we show that an adaptive allele of iscR, encoding a major regulator of iron homeostasis of Escherichia coli, is under fluctuating selection in the mouse gut. In vivo competitions in immune-competent, immune-compromised, and germ-free mice reveal that the selective pressure on an iscR mutant E. coli is modulated by the presence of antibiotics, other members of the microbiota, and the immune system. In vitro assays show that iron availability is an important mediator of the iscR allele fitness benefits or costs. We identify Lipocalin-2, a host's innate immune system protein that prevents bacterial iron acquisition, as a major host mechanism underlying fluctuating selection of the iscR allele. Our results provide a remarkable example of strong fluctuating selection acting on bacterial iron regulation in the mammalian gut.

DksA is a central regulatory switch for stress protection and virulence in Acinetobacter baumannii

2021 ◽  
Author(s):  
Ram Maharjan ◽  
Geraldine Sulivan ◽  
Felise Adams ◽  
Natasha Delgado ◽  
Lucie Semenec ◽  
...  
Keyword(s):  
Stress Response ◽  
Acinetobacter Baumannii ◽  
Galleria Mellonella ◽  
Resistance Mechanisms ◽  
Term Survival ◽  
In Vivo Models ◽  
Molecular Control ◽  
Stress Protection

Abstract Bacterial coordination of stress resistance mechanisms in harsh environments is key to long-term survival and evolutionary success. In many Gram-negative pathogens, both general- and specific-stress response are controlled by alternative sigma factors such as RpoS. The critically important pathogen Acinetobacter baumannii is notoriously recalcitrant to external stressors, yet it lacks RpoS, so the molecular control of its resilience remains unclear. Here, we used transposon insertion sequencing to characterize the molecular responses of Acinetobacter baumannii to two biologically-important metals stressors, zinc and copper, and discovered that the transcriptional regulator DksA acts as a major regulatory stress-protection switch. We mapped the highly pleiotropic nature of DksA using transcriptomics and phenomics and found that it controls ribosomal protein expression, metabolism of gluconeogenic substrates and survival in stresses that cause oxidative damage. A. baumannii strains lacking DksA were no longer virulent in both murine and Galleria mellonella in vivo models. In vitro, DksA mutants exhibited increased sensitivity to human serum and antibiotics yet promoted biofilm and capsule formation. Our study provides detailed insight into the unique role that DksA plays in stress protection and virulence for A. baumannii and lays the groundwork for understanding of RpoS-independent regulatory general stress response.

scholarly journals Spatially Distinct Neutrophil Responses within the Inflammatory Lesions of Pneumonic Plague

mBio ◽  
2015 ◽  
Vol 6 (5) ◽  
Author(s):  
Nikolas M. Stasulli ◽  
Kara R. Eichelberger ◽  
Paul A. Price ◽  
Roger D. Pechous ◽  
Stephanie A. Montgomery ◽  
...  
Keyword(s):  
Yersinia Pestis ◽  
Cell Types ◽  
Lung Lesions ◽  
Pneumonic Plague ◽  
Content Type ◽  
Microbe Interactions ◽  
Host Microbe Interactions ◽  
Neutrophil Survival

ABSTRACTDuring pneumonic plague, the bacteriumYersinia pestiselicits the development of inflammatory lung lesions that continue to expand throughout infection. This lesion development and persistence are poorly understood. Here, we examine spatially distinct regions of lung lesions using laser capture microdissection and transcriptome sequencing (RNA-seq) analysis to identify transcriptional differences between lesion microenvironments. We show that cellular pathways involved in leukocyte migration and apoptosis are downregulated in the center of lung lesions compared to the periphery. Probing for the bacterial factor(s) important for the alteration in neutrophil survival, we show bothin vitroandin vivothatY. pestisincreases neutrophil survival in a manner that is dependent on the type III secretion system effector YopM. This research explores the complexity of spatially distinct host-microbe interactions and emphasizes the importance of cell relevance in assays in order to fully understandY. pestisvirulence.IMPORTANCEYersinia pestisis a high-priority pathogen and continues to cause outbreaks worldwide. The ability ofY. pestisto be transmitted via respiratory droplets and its history of weaponization has led to its classification as a select agent most likely to be used as a biological weapon. Unrestricted bacterial growth during the initial preinflammatory phase primes patients to be infectious once disease symptoms begin in the proinflammatory phase, and the rapid disease progression can lead to death beforeY. pestisinfection can be diagnosed and treated. Usingin vivoanalyses and focusing on relevant cell types during pneumonic plague infection, we can identify host pathways that may be manipulated to extend the treatment window for pneumonic plague patients.

scholarly journals Acetylcholine Protects against Candida albicans Infection by Inhibiting Biofilm Formation and Promoting Hemocyte Function in a Galleria mellonella Infection Model

2015 ◽  
Vol 14 (8) ◽  
pp. 834-844 ◽  
Author(s):  
Ranjith Rajendran ◽  
Elisa Borghi ◽  
Monica Falleni ◽  
Federica Perdoni ◽  
Delfina Tosi ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Biofilm Formation ◽  
Galleria Mellonella ◽  
Inflammatory Responses ◽  
Fungal Infections ◽  
Infection Model ◽  
Content Type

ABSTRACT Both neuronal acetylcholine and nonneuronal acetylcholine have been demonstrated to modulate inflammatory responses. Studies investigating the role of acetylcholine in the pathogenesis of bacterial infections have revealed contradictory findings with regard to disease outcome. At present, the role of acetylcholine in the pathogenesis of fungal infections is unknown. Therefore, the aim of this study was to determine whether acetylcholine plays a role in fungal biofilm formation and the pathogenesis of Candida albicans infection. The effect of acetylcholine on C. albicans biofilm formation and metabolism in vitro was assessed using a crystal violet assay and phenotypic microarray analysis. Its effect on the outcome of a C. albicans infection, fungal burden, and biofilm formation were investigated in vivo using a Galleria mellonella infection model. In addition, its effect on modulation of host immunity to C. albicans infection was also determined in vivo using hemocyte counts, cytospin analysis, larval histology, lysozyme assays, hemolytic assays, and real-time PCR. Acetylcholine was shown to have the ability to inhibit C. albicans biofilm formation in vitro and in vivo . In addition, acetylcholine protected G. mellonella larvae from C. albicans infection mortality. The in vivo protection occurred through acetylcholine enhancing the function of hemocytes while at the same time inhibiting C. albicans biofilm formation. Furthermore, acetylcholine also inhibited inflammation-induced damage to internal organs. This is the first demonstration of a role for acetylcholine in protection against fungal infections, in addition to being the first report that this molecule can inhibit C. albicans biofilm formation. Therefore, acetylcholine has the capacity to modulate complex host-fungal interactions and plays a role in dictating the pathogenesis of fungal infections.

scholarly journals In vitro cell and tissue models for studying host–microbe interactions: a review

2013 ◽  
Vol 109 (S2) ◽  
pp. S27-S34 ◽  
Author(s):  
Miriam Bermudez-Brito ◽  
Julio Plaza-Díaz ◽  
Luis Fontana ◽  
Sergio Muñoz-Quezada ◽  
Angel Gil
Keyword(s):  
Epithelial Cells ◽  
Molecular Mechanisms ◽  
Three Dimensional ◽  
Experimental Models ◽  
Dynamic Interactions ◽  
Basolateral Side ◽  
Microbe Interactions ◽  
Host Microbe Interactions

Ideally, cell models should resemble the in vivo conditions; however, in most in vitro experimental models, epithelial cells are cultivated as monolayers, in which the establishment of functional epithelial features is not achieved. To overcome this problem, co-culture experiments with probiotics, dendritic cells and intestinal epithelial cells and three-dimensional models attempt to reconcile the complex and dynamic interactions that exist in vivo between the intestinal epithelium and bacteria on the luminal side and between the epithelium and the underlying immune system on the basolateral side. Additional models include tissue explants, bioreactors and organoids. The present review details the in vitro models used to study host–microbe interactions and explores the new tools that may help in understanding the molecular mechanisms of these interactions.

scholarly journals Galleria mellonella for the Evaluation of Antifungal Efficacy against Medically Important Fungi, a Narrative Review

2020 ◽  
Vol 8 (3) ◽  
pp. 390 ◽  
Author(s):  
Sana Jemel ◽  
Jacques Guillot ◽  
Kalthoum Kallel ◽  
Françoise Botterel ◽  
Eric Dannaoui
Keyword(s):  
Fungal Pathogens ◽  
Galleria Mellonella ◽  
Fungal Infections ◽  
Antifungal Susceptibility ◽  
Antifungal Drugs ◽  
New Drugs ◽  
Development Of Resistance ◽  
Antifungal Efficacy

The treatment of invasive fungal infections remains challenging and the emergence of new fungal pathogens as well as the development of resistance to the main antifungal drugs highlight the need for novel therapeutic strategies. Although in vitro antifungal susceptibility testing has come of age, the proper evaluation of therapeutic efficacy of current or new antifungals is dependent on the use of animal models. Mammalian models, particularly using rodents, are the cornerstone for evaluation of antifungal efficacy, but are limited by increased costs and ethical considerations. To circumvent these limitations, alternative invertebrate models, such as Galleria mellonella, have been developed. Larvae of G. mellonella have been widely used for testing virulence of fungi and more recently have proven useful for evaluation of antifungal efficacy. This model is suitable for infection by different fungal pathogens including yeasts (Candida, Cryptococcus, Trichosporon) and filamentous fungi (Aspergillus, Mucorales). Antifungal efficacy may be easily estimated by fungal burden or mortality rate in infected and treated larvae. The aim of the present review is to summarize the actual data about the use of G. mellonella for testing the in vivo efficacy of licensed antifungal drugs, new drugs, and combination therapies.

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