RNA Interference-Mediated Silencing of the<i>YPS3</i>Gene of<i>Histoplasma capsulatum</i>Reveals Virulence Defects

Bohse, Megan L.; Woods, Jon P.

doi:10.1128/iai.00304-07

Cited by 62 publications

(57 citation statements)

References 26 publications

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“…RNAi in H. capsulatum can often be inefficient or highly variable (5,25,31), and so we disrupted HcDPPIVA (Fig. 4A).…”

Section: Resultsmentioning

confidence: 99%

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Secreted Dipeptidyl Peptidase IV Activity in the Dimorphic Fungal PathogenHistoplasma capsulatum

Cooper

Woods

2009

Infect Immun

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Dipeptidyl peptidase type IV (DppIV) enzymes are broadly distributed phylogenetically and display diverse functions, including intercellular signaling, immunomodulation, protein maturation and processing, metabolism, and nutrient acquisition. We identified a secreted proteolytic activity in Histoplasma capsulatum effective toward DppIV-specific substrates. In order to determine the gene(s) that encodes this activity, we identified two putative DPPIV homologs (HcDPPIVA and HcDPPIVB) in H. capsulatum based on a homology search with Aspergillus fumigatus DppIV. Comparative sequence analysis revealed that HcDppIVA is similar to secreted DppIV enzymes, while HcDppIVB clusters with intracellular DapB-like enzymes. Unexpectedly, silencing of HcDPPIVA by RNA interference (RNAi) had no effect on secreted DppIV activity and an HcDPPIVA-null deletion mutant also showed no abrogation of secreted DppIV activity. In contrast, RNAi silencing of HcDPPIVB significantly reduced the level of secreted DppIV activity. RNAi silencing of HcDPPIVB in the HcDPPIVA-null mutant had no additional effect on secreted DppIV activity, indicating that HcDPPIVA does not contribute to secreted activity. RNAi silencing of HcDPPIVB did not affect the ability to kill a murine macrophage-like cell line, RAW 264.7, indicating that this gene is not required for infection of macrophages.

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“…RNAi in H. capsulatum can often be inefficient or highly variable (5,25,31), and so we disrupted HcDPPIVA (Fig. 4A).…”

Section: Resultsmentioning

confidence: 99%

“…The virulence of H. capsulatum was evaluated by determining its ability to kill RAW 264.7 cells as previously described (5,26). Briefly, RAW 264.7 cells were seeded into 96-well culture plates at a density of 2 ϫ 10 4 /well.…”

Section: Strains and Mediamentioning

confidence: 99%

Secreted Dipeptidyl Peptidase IV Activity in the Dimorphic Fungal PathogenHistoplasma capsulatum

Cooper

Woods

2009

Infect Immun

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“…For example, the virulence factor CBP1 (22) was highly expressed only in wild-type yeast cells but not in wild-type filaments or in ryp1 mutant cells grown at either 37°C or room temperature (see SI Table 1). Similarly, the YPS3 gene (23), which was recently shown to be required for colonization of the lungs, liver, and spleen during infection of mice (24), was highly expressed in wild-type yeast cells but not in wild-type filaments (grown at room temperature) or ryp1 mutant filaments (grown at 37°C), suggesting that RYP1 was required to activate expression of YPS3 at 37°C. Additionally, the YPS3 gene was highly expressed in ryp1 mutant filaments grown at room temperature, suggesting that RYP1 was also required to inhibit inappropriate expression of YPS3 during room-temperature growth.…”

Section: Ryp1 Is Required For Differential Expression Of Genes In Resmentioning

confidence: 99%

Temperature-induced switch to the pathogenic yeast form of Histoplasma capsulatum requires Ryp1, a conserved transcriptional regulator

Nguyen

Sil

2008

Proc. Natl. Acad. Sci. U.S.A.

174

207

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Histoplasma capsulatum, a fungal pathogen of humans, switches from a filamentous spore-forming mold in the soil to a pathogenic budding-yeast form in the human host. This morphologic switch, which is exhibited by H. capsulatum and a group of evolutionarily related fungal pathogens, is regulated by temperature. Using insertional mutagenesis, we identified a gene, RYP1 (required for yeast phase growth), which is required for yeast-form growth at 37°C. ryp1 mutants are constitutively filamentous irrespective of temperature. Ryp1 is a member of a family of fungal proteins that includes Wor1, a master transcriptional regulator of the whiteopaque transition required for mating in Candida albicans. Ryp1 associates with its own upstream regulatory region, consistent with a direct role in transcriptional control, and both the protein and its transcript accumulate to high levels in wild-type yeastphase cells. Microarray analysis demonstrated that Ryp1 is required for the expression of the vast majority of yeast-specific genes, including two genes linked to virulence. Thus, Ryp1 appears to be a critical transcriptional regulator of a temperature-regulated morphologic switch in H. capsulatum.fungal pathogenesis ͉ gene regulation ͉ morphology

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“…It is one such respiratory fungal infection that accounts for about half a million cases per year only in the US. 108 The ability of H. capsulatum to form biofilms remained unknown for a long time until identified by Suárez-Alvarez et al 109 The researchers showed that H. capsulatum yeasts could adhere to the cryosections of different organs and further provided evidence for an important mechanism of colonization and spread of the yeasts, which involves adhesion of the microorganisms to the host tissues, including the cell surface and extracellular components. Two years later, Pitangui et al 110 demonstrated the in vitro ability of H. capsulatum to form biofilms and evaluated its invasion potential in cell lines.…”

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confidence: 99%

Nanotechnology-based drug delivery systems for control of microbial biofilms: a review

Ramos¹,

Silva²,

Spósito³

et al. 2018

IJN

220

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Since the dawn of civilization, it has been understood that pathogenic microorganisms cause infectious conditions in humans, which at times, may prove fatal. Among the different virulent properties of microorganisms is their ability to form biofilms, which has been directly related to the development of chronic infections with increased disease severity. A problem in the elimination of such complex structures (biofilms) is resistance to the drugs that are currently used in clinical practice, and therefore, it becomes imperative to search for new compounds that have anti-biofilm activity. In this context, nanotechnology provides secure platforms for targeted delivery of drugs to treat numerous microbial infections that are caused by biofilms. Among the many applications of such nanotechnology-based drug delivery systems is their ability to enhance the bioactive potential of therapeutic agents. The present study reports the use of important nanoparticles, such as liposomes, microemulsions, cyclodextrins, solid lipid nanoparticles, polymeric nanoparticles, and metallic nanoparticles, in controlling microbial biofilms by targeted drug delivery. Such utilization of these nanosystems has led to a better understanding of their applications and their role in combating biofilms.

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RNA Interference-Mediated Silencing of theYPS3Gene ofHistoplasma capsulatumReveals Virulence Defects

Cited by 62 publications

References 26 publications

Secreted Dipeptidyl Peptidase IV Activity in the Dimorphic Fungal PathogenHistoplasma capsulatum

Secreted Dipeptidyl Peptidase IV Activity in the Dimorphic Fungal PathogenHistoplasma capsulatum

Temperature-induced switch to the pathogenic yeast form of Histoplasma capsulatum requires Ryp1, a conserved transcriptional regulator

Nanotechnology-based drug delivery systems for control of microbial biofilms: a review

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