In vitroandex vivoinfection models help assess the molecular aspects of the interaction ofTrichophyton rubrumwith the host milieu

Peres, Nalu T. A.; Silva, Larissa Gomes da; Santos, Rodrigo da Silva; Jacob, Tiago Rinaldi; Persinoti, Gabriela Félix; Rocha, Lenaldo Branco; Falcão, Juliana Pfrimer; Rossi, Antônio; Martinez-Rossi, Nilce M.

doi:10.1093/mmy/myv113

Cited by 38 publications

(25 citation statements)

References 35 publications

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“…Simulation of the host milieu is widely employed in investigations to assess putative virulence factors. Within this context, liquid media containing keratin powder, protein and even macerated skin have been used to elucidate key aspects of T. rubrum pathophysiology [6].…”

Section: Discussionmentioning

confidence: 99%

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Trans-chalcone activity against Trichophyton rubrum relies on an interplay between signaling pathways related to cell wall integrity and fatty acid metabolism

et al. 2019

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Background Trichophyton rubrum is the main etiological agent of skin and nail infections worldwide. Because of its keratinolytic activity and anthropophilic nature, infection models based on the addition of protein substrates have been employed to assess transcriptional profiles and to elucidate aspects related to host-pathogen interactions. Chalcones are widespread compounds with pronounced activity against dermatophytes. The toxicity of trans -chalcone towards T. rubrum is not fully understood but seems to rely on diverse cellular targets. Within this context, a better understanding of the mode of action of trans -chalcone may help identify new strategies of antifungal therapy and reveal new chemotherapeutic targets. This work aimed to assess the transcriptional profile of T. rubrum grown on different protein sources (keratin or elastin) to mimic natural infection sites and exposed to trans -chalcone in order to elucidate the mechanisms underlying the antifungal activity of trans- chalcone. Results Overall, the use of different protein sources caused only slight differences in the transcriptional profile of T. rubrum . The main differences were the modulation of proteases and lipases in gene categories when T. rubrum was grown on keratin and elastin, respectively. In addition, some genes encoding heat shock proteins were up-regulated during the growth of T. rubrum on keratin. The transcriptional profile of T. rubrum exposed to trans -chalcone included four main categories: fatty acid and lipid metabolism, overall stress response, cell wall integrity pathway, and alternative energy metabolism. Consistently, T. rubrum Mapk was strongly activated during the first hours of trans -chalcone exposure. Noteworthy, trans- chalcone inhibited genes involved in keratin degradation. The results also showed effects of trans -chalcone on fatty acid synthesis and metabolic pathways involved in acetyl-CoA supply. Conclusion Our results suggest that the mode of action of trans -chalcone is related to pronounced changes in fungal metabolism, including an imbalance between fatty acid synthesis and degradation that interferes with cell membrane and cell wall integrity. In addition, this compound exerts activity against important virulence factors. Taken together, trans -chalcone acts on targets related to dermatophyte physiology and the infection process. Electronic supplementary material The online version of this article (10.1186/s12864-019-5792-0) contains supp...

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Section: Discussionmentioning

confidence: 99%

“…Seven dermatophytes genomes have been sequenced [4, 5], which will provide the basis for a better understanding of their pathophysiological mechanisms. Additionally, in vitro and ex vivo models that mimic host-fungal interactions have been employed in order to identify new molecular targets [6].…”

Section: Introductionmentioning

confidence: 99%

Trans-chalcone activity against Trichophyton rubrum relies on an interplay between signaling pathways related to cell wall integrity and fatty acid metabolism

et al. 2019

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“…Trichophyton rubrum CBS118892 strain (Centraalbureau voor Schimmelcultures, Fungal Biodiversity Centre, Netherlands) was cultivated in malt extract at 28 • C, as previously described (Peres et al, 2016). Conidia suspension was obtained from 20-daysold plates, and the concentration was estimated by using a Newbauer chamber.…”

Section: Strain and Culture Conditionsmentioning

confidence: 99%

“…Nail interaction assay was performed as previously described (Peres et al, 2016) with minor modifications. Human nail fragments (approximately 25 cm 2 ) were sterilized by autoclaving.…”

Section: Coculture and Nail Infectionmentioning

confidence: 99%

HacA Governs Virulence Traits and Adaptive Stress Responses in Trichophyton rubrum

et al. 2020

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The ability of fungi to sense environmental stressors and appropriately respond is linked to secretory system functions. The dermatophyte infection process depends on an orchestrated signaling regulation that triggers the transcription of genes responsible for adherence and penetration of the pathogen into host-tissue. A high secretion system is activated to support the host-pathogen interaction and assures maintenance of the dermatophyte infection. The gateway of secretion machinery is the endoplasmic reticulum (ER), which is the primary site for protein folding and transport. Current studies have shown that ER stress that affects adaptive responses is primarily regulated by UPR and supports fungal pathogenicity; this has been assessed for yeasts and Aspergillus fumigatus, in regard to how these fungi cope with host environmental stressors. Fungal UPR consists of a transmembrane kinase sensor (Ire1/IreA) and a downstream target Hac1/HacA. The active form of Hac is achieved via non-spliceosomal intron removal promoted by endonuclease activity of Ire1/IreA. Here, we assessed features of HacA and its involvement in virulence and susceptibility in Trichophyton rubrum. Our results showed that exposure to antifungals and ER-stressing agents initiated the activation of HacA from T. rubrum. Interestingly, the activation occurs when a 20 nt fragment is removed from part of the exon-2 and part of intron-2, which in turn promotes the arisen of the DNA binding site motif and a dimer interface domain. Further, we found changes in the cell wall and cellular membrane composition in the hacA mutant as well as an increase in susceptibility toward azole and cell wall disturbing agents. Moreover, the hacA mutant presented significant defects in important virulence traits like thermotolerance and growth on keratin substrates. For instance, the development of the hacA mutant was impaired in co-culture with keratinocytes or human nail fragments. Changes in the pro-inflammatory cytokine release were verified for the hacA mutant during the co-culture assay, which might be related to differences in pathogen-associated molecular patterns (PAMPs) in the cell wall. Together, these results suggested that HacA is an integral part of T. rubrum physiology and virulence, implying that it is an important molecular target for antidermatophytic therapy.

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“…The use of human skin explants obtained from surgery has allowed ex vivo study of skin barrier repair 15 , wound healing 16 , chemical toxicity 17 , chronic inflammatory diseases 18 , DNA vaccination 19 , and fungal infection 20 – 22 . In this study we used NativeSkin skin explants to create a burn wound model of candidiasis.…”

Section: Introductionmentioning

confidence: 99%

Active neutrophil responses counteract Candida albicans burn wound infection of ex vivo human skin explants

Müller

Bulman

Wagner

et al. 2020

Sci Rep

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Burn wounds are highly susceptible sites for colonization and infection by bacteria and fungi. Large wound surface, impaired local immunity, and broad-spectrum antibiotic therapy support growth of opportunistic fungi such as Candida albicans, which may lead to invasive candidiasis. Currently, it remains unknown whether depressed host defenses or fungal virulence drive the progression of burn wound candidiasis. Here we established an ex vivo burn wound model, where wounds were inflicted by applying preheated soldering iron to human skin explants, resulting in highly reproducible deep second-degree burn wounds. Eschar removal by debridement allowed for deeper C. albicans penetration into the burned tissue associated with prominent filamentation. Active migration of resident tissue neutrophils towards the damaged tissue and release of pro-inflammatory cytokine IL-1β accompanied the burn. The neutrophil recruitment was further increased upon supplementation of the model with fresh immune cells. Wound area and depth decreased over time, indicating healing of the damaged tissue. Importantly, prominent neutrophil presence at the infected site correlated to the limited penetration of C. albicans into the burned tissue. Altogether, we established a reproducible burn wound model of candidiasis using ex vivo human skin explants, where immune responses actively control the progression of infection and promote tissue healing.

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In vitroandex vivoinfection models help assess the molecular aspects of the interaction ofTrichophyton rubrumwith the host milieu

Cited by 38 publications

References 35 publications

Trans-chalcone activity against Trichophyton rubrum relies on an interplay between signaling pathways related to cell wall integrity and fatty acid metabolism

Trans-chalcone activity against Trichophyton rubrum relies on an interplay between signaling pathways related to cell wall integrity and fatty acid metabolism

HacA Governs Virulence Traits and Adaptive Stress Responses in Trichophyton rubrum

Active neutrophil responses counteract Candida albicans burn wound infection of ex vivo human skin explants

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