1
|
Das S, Singh S, Tawde Y, Dutta TK, Rudramurthy SM, Kaur H, Shaw T, Ghosh A. Comparative fitness trade-offs associated with azole resistance in Candida auris clinical isolates. Heliyon 2024; 10:e32386. [PMID: 38988564 PMCID: PMC11233892 DOI: 10.1016/j.heliyon.2024.e32386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 05/31/2024] [Accepted: 06/03/2024] [Indexed: 07/12/2024] Open
Abstract
Multidrug-resistant yeast Candida auris is a serious threat to public health with documented survival in various hospital niches. The dynamics of this survival benefit and its trade off with drug resistance are still unknown for this pathogen. In this study we investigate the oxidative stress response (OSR) in fluconazole-resistant C. auris and compare its relative fitness with fluconazole-susceptible strains. A total of 351 C. auris clinical isolates (61 fluconazole-susceptible and 290 fluconazole-resistant) were screened for stress tolerance by spot assay and 95.08 % fluconazole-susceptible isolates were hyper-resistant to oxidative stress while majority (94.5 %) fluconazole-resistant isolates had lower oxidative tolerance. Expression of Hog1 and Cta1 gene transcript levels and cellular catalase levels were significantly higher in fluconazole-susceptible isolates and a corresponding higher intracellular reactive oxygen species level (iROS) was accumulated in the fluconazole-resistant isolates. Biofilm formation and cell viability under oxidative stress revealed higher biofilm formation and better viability in fluconazole-susceptible isolates. Fluconazole-resistant isolates had higher basal cell wall chitin. On comparison of virulence, the % cytotoxicity in A549 cell line was higher in fluconazole-susceptible isolates and the median survival of the infected larvae in G. mellonella infection model was higher in fluconazole-resistant (5; IQR:4.5-5 days) vs. fluconazole-susceptible C. auris (2; IQR:1.5-2.5 days). All organisms evolve with changes in their environmental conditions, to ensure an optimal balance between proliferation and survival. Development of tolerance to a certain kind of stress example antifungal exposure in yeast can leads to a compensatory decrease in tolerance for other stresses. This study provides useful insights into the comparative fitness and antifungal susceptibility trade off in C. auris. We report a negative association between H2O2 tolerance and fluconazole susceptibility. Using in-vitro cell cytotoxicity and in-vivo survival assays we also demonstrate the higher virulence potential of fluconazole-susceptible C. auris isolates corroborating the negative correlation between susceptibility and pathogen survival or virulence. These findings could also be translated to clinical practice by investigating the possibility of using molecules targeting stress response and fitness regulating pathways for management of this serious infection.
Collapse
Affiliation(s)
- Sourav Das
- Department of Medical Microbiology. Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Shreya Singh
- Department of Microbiology. Dr. B. R. Ambedkar State Institute of Medical Science, Mohali, Punjab, India
| | - Yamini Tawde
- Department of Medical Microbiology. Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Tushar K. Dutta
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Shivaprakash M. Rudramurthy
- Department of Medical Microbiology. Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Harsimran Kaur
- Department of Medical Microbiology. Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Tushar Shaw
- Department of Life and Allied Health Sciences, Ramaiah university of Applied sciences, Bangalore, India
| | - Anup Ghosh
- Department of Medical Microbiology. Post Graduate Institute of Medical Education and Research, Chandigarh, India
| |
Collapse
|
2
|
Saeed N, Valiante V, Kufs JE, Hillmann F. The isoprenyl chain length of coenzyme Q mediates the nutritional resistance of fungi to amoeba predation. mBio 2024; 15:e0034224. [PMID: 38747615 PMCID: PMC11237637 DOI: 10.1128/mbio.00342-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 04/09/2024] [Indexed: 06/13/2024] Open
Abstract
Amoebae are environmental predators feeding on bacteria, fungi, and other eukaryotic microbes. Predatory interactions alter microbial communities and impose selective pressure toward phagocytic resistance or escape which may, in turn, foster virulence attributes. The ubiquitous fungivorous amoeba Protostelium aurantium has a wide prey spectrum in the fungal kingdom but discriminates against members of the Saccharomyces clade, such as Saccharomyces cerevisiae and Candida glabrata. Here, we show that this prey discrimination among fungi is solely based on the presence of ubiquinone as an essential cofactor for the predator. While the amoeba readily fed on fungi with CoQ presenting longer isoprenyl side chain variants CoQ8-10, such as those from the Candida clade, it failed to proliferate on those with shorter CoQ variants, specifically from the Saccharomyces clade (CoQ6). Supplementing non-edible yeast with CoQ9 or CoQ10 rescued the growth of P. aurantium, highlighting the importance of a long isoprenyl side chain. Heterologous biosynthesis of CoQ9 in S. cerevisiae by introducing genes responsible for CoQ9 production from the evolutionary more basic Yarrowia lipolytica complemented the function of the native CoQ6. The results suggest that the use of CoQ6 among members of the Saccharomyces clade might have originated as a predatory escape strategy in fungal lineages and could be retained in organisms that were able to thrive by fermentation. IMPORTANCE Ubiquinones (CoQ) are universal electron carriers in the respiratory chain of all aerobic bacteria and eukaryotes. Usually 8-10 isoprenyl units ensure their localization within the lipid bilayer. Members of the Saccharomyces clade among fungi are unique in using only 6. The reason for this is unclear. Here we provide evidence that the use of CoQ6 efficiently protects these fungi from predation by the ubiquitous fungivorous amoeba Protostelium aurantium which lacks its own biosynthetic pathway for this vitamin. The amoebae were starving on a diet of CoQ6 yeasts which could be complemented by either the addition of longer CoQs or the genetic engineering of a CoQ9 biosynthetic pathway.
Collapse
Affiliation(s)
- Nauman Saeed
- Evolution of Microbial Interactions, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Jena, Germany
- Institute of Microbiology, Faculty of Biological Sciences, Friedrich Schiller University Jena, Jena, Germany
- Biochemistry/Biotechnology, Faculty of Engineering, Wismar University of Applied Sciences Technology, Business and Design, Wismar, Germany
| | - Vito Valiante
- Biobricks of Microbial Natural Product Syntheses, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Jena, Germany
| | - Johann E Kufs
- Genome Engineering and Editing, Faculty of Technology, Bielefeld University, Bielefeld, Germany
| | - Falk Hillmann
- Biochemistry/Biotechnology, Faculty of Engineering, Wismar University of Applied Sciences Technology, Business and Design, Wismar, Germany
| |
Collapse
|
3
|
Nickerson KW, Gutzmann DJ, Boone CHT, Pathirana RU, Atkin AL. Physiological adventures in Candida albicans: farnesol and ubiquinones. Microbiol Mol Biol Rev 2024; 88:e0008122. [PMID: 38436263 PMCID: PMC10966945 DOI: 10.1128/mmbr.00081-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2024] Open
Abstract
SUMMARYFarnesol was first identified as a quorum-sensing molecule, which blocked the yeast to hyphal transition in Candida albicans, 22 years ago. However, its interactions with Candida biology are surprisingly complex. Exogenous (secreted or supplied) farnesol can also act as a virulence factor during pathogenesis and as a fungicidal agent triggering apoptosis in other competing fungi. Farnesol synthesis is turned off both during anaerobic growth and in opaque cells. Distinctly different cellular responses are observed as exogenous farnesol levels are increased from 0.1 to 100 µM. Reported changes include altered morphology, stress response, pathogenicity, antibiotic sensitivity/resistance, and even cell lysis. Throughout, there has been a dearth of mechanisms associated with these observations, in part due to the absence of accurate measurement of intracellular farnesol levels (Fi). This obstacle has recently been overcome, and the above phenomena can now be viewed in terms of changing Fi levels and the percentage of farnesol secreted. Critically, two aspects of isoprenoid metabolism present in higher organisms are absent in C. albicans and likely in other yeasts. These are pathways for farnesol salvage (converting farnesol to farnesyl pyrophosphate) and farnesylcysteine cleavage, a necessary step in the turnover of farnesylated proteins. Together, these developments suggest a unifying model, whereby high, threshold levels of Fi regulate which target proteins are farnesylated or the extent to which they are farnesylated. Thus, we suggest that the diversity of cellular responses to farnesol reflects the diversity of the proteins that are or are not farnesylated.
Collapse
Affiliation(s)
| | - Daniel J. Gutzmann
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA
| | - Cory H. T. Boone
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA
| | - Ruvini U. Pathirana
- Department of Biology and Chemistry, Texas A&M International University, Laredo, Texas, USA
| | - Audrey L. Atkin
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA
| |
Collapse
|
4
|
Boone CHT, Parker KA, Gutzmann DJ, Atkin AL, Nickerson KW. Farnesol as an antifungal agent: comparisons among MTLa and MTLα haploid and diploid Candida albicans and Saccharomyces cerevisiae. Front Physiol 2023; 14:1207567. [PMID: 38054042 PMCID: PMC10694251 DOI: 10.3389/fphys.2023.1207567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 11/09/2023] [Indexed: 12/07/2023] Open
Abstract
Aims: Farnesol was identified 20 years ago in a search for Candida albicans quorum sensing molecules (QSM), but there is still uncertainty regarding many aspects of its mode of action including whether it employs farnesol transport mechanisms other than diffusion. Based on the structural similarity between farnesol and the farnesylated portion of the MTL a pheromone, we explored the effects of ploidy and mating type locus (MTL) on the antifungal activity of exogenous farnesol. Methods and results: We approached this question by examining five MTL a and five MTLα haploid strains with regard to their farnesol sensitivity in comparison to six heterozygous MTL a/ α diploids. We examined the haploid and diploid strains for percent cell death after exposure of exponentially growing cells to 0-200 µM farnesol. The heterozygous (MTL a/α) diploids were tolerant of exogenous farnesol whereas the MTL a and MTLα haploids were on average 2- and 4-times more sensitive, respectively. In the critical range from 10-40 µM farnesol their cell death values were in the ratio of 1:2:4. Very similar results were obtained with two matched sets of MAT a, MATα, and MAT a/α Saccharomyces cerevisiae strains. Conclusion: We propose that the observed MTL dependence of farnesol is based on differentially regulated mechanisms of entry and efflux which determine the actual cellular concentration of farnesol. The mechanisms by which pathogens such as C. albicans tolerate the otherwise lethal effects of farnesol embrace a wide range of physiological functions, including MTL type, ubiquinone type (UQ6-UQ9), energy availability, and aerobic/anaerobic status.
Collapse
Affiliation(s)
| | | | | | | | - Kenneth W. Nickerson
- School of Biological Sciences, University of Nebraska, Lincoln, NE, United States
| |
Collapse
|
5
|
Zheng D, Yue D, Shen J, Li D, Song Z, Huang Y, Yong J, Li Y. Berberine inhibits Candida albicans growth by disrupting mitochondrial function through the reduction of iron absorption. J Appl Microbiol 2023; 134:lxad276. [PMID: 37994672 DOI: 10.1093/jambio/lxad276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 11/04/2023] [Accepted: 11/21/2023] [Indexed: 11/24/2023]
Abstract
AIMS This study aimed to investigate whether berberine (BBR) can inhibit the iron reduction mechanism of Candida albicans, lowering the iron uptake of the yeast and perhaps having antimicrobial effects. METHODS AND RESULTS We determined that BBR may cause extensive transcriptional remodeling in C. albicans and that iron permease Ftr1 played a crucial role in this process through eukaryotic transcriptome sequencing. Mechanistic research showed that BBR might selectively inhibit the iron reduction pathway to lower the uptake of exogenous iron ions, inhibiting C. albicans from growing and metabolizing. Subsequent research revealed that BBR caused significant mitochondrial dysfunction, which triggered the process of mitochondrial autophagy. Moreover, we discovered that C. albicans redox homeostasis, susceptibility to antifungal drugs, and hyphal growth are all impacted by the suppression of this mechanism by BBR. CONCLUSIONS The iron reduction mechanism in C. albicans is disrupted by BBR, which disrupts mitochondrial function and inhibits fungal growth. These findings highlight the potential promise of BBR in antifungal applications.
Collapse
Affiliation(s)
- Dongming Zheng
- College of Medical Technology, Chengdu University of Traditional Chinese Medicine, Sichuan 611137, China
| | - Daifan Yue
- College of Medical Technology, Chengdu University of Traditional Chinese Medicine, Sichuan 611137, China
| | - Jinyang Shen
- College of Medical Technology, Chengdu University of Traditional Chinese Medicine, Sichuan 611137, China
| | - Dongmei Li
- College of Medical Technology, Chengdu University of Traditional Chinese Medicine, Sichuan 611137, China
| | - Zhen Song
- College of Medical Technology, Chengdu University of Traditional Chinese Medicine, Sichuan 611137, China
| | - Yifu Huang
- College of Medical Technology, Chengdu University of Traditional Chinese Medicine, Sichuan 611137, China
| | - Jiangyan Yong
- Hospital of Chengdu University of Traditional Chinese Medicine, Sichuan 610075, China
| | - Yan Li
- College of Medical Technology, Chengdu University of Traditional Chinese Medicine, Sichuan 611137, China
| |
Collapse
|
6
|
Gutzmann DJ, Kramer JJ, Toomey BM, Boone CHT, Atkin AL, Nickerson KW. Transcriptional regulation of the synthesis and secretion of farnesol in the fungus Candida albicans: examination of the Homann transcription regulator knockout collection. G3 (BETHESDA, MD.) 2023; 13:jkad172. [PMID: 37522561 PMCID: PMC10542173 DOI: 10.1093/g3journal/jkad172] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 07/18/2023] [Accepted: 07/21/2023] [Indexed: 08/01/2023]
Abstract
Candida albicans is an efficient colonizer of human gastrointestinal tracts and skin and is an opportunistic pathogen. C. albicans exhibits morphological plasticity, and the ability to switch between yeast and filamentous morphologies is associated with virulence. One regulator of this switch is the quorum sensing molecule farnesol that is produced by C. albicans throughout growth. However, the synthesis, secretion, regulation, and turnover of farnesol are not fully understood. To address this, we used our improved farnesol assay to screen a transcription regulator knockout library for differences in farnesol accumulation in whole cultures, pellets, and supernatants. All screened mutants produced farnesol and they averaged 9.2× more farnesol in the pellet than the supernatant. Nineteen mutants had significant differences with ten mutants producing more farnesol than their SN152+ wild-type control strain while nine produced less. Seven mutants exhibited greater secretion of farnesol while two exhibited less. We examined the time course for farnesol accumulation in six mutants with the greatest accumulation differences and found that those differences persisted throughout growth and they were not time dependent. Significantly, two high-accumulating mutants did not exhibit the decay in farnesol levels during stationary phase characteristic of wild-type C. albicans, suggesting that a farnesol modification/degradation mechanism is absent in these mutants. Identifying these transcriptional regulators provides new insight into farnesol's physiological functions regarding cell cycle progression, white-opaque switching, yeast-mycelial dimorphism, and response to cellular stress.
Collapse
Affiliation(s)
- Daniel J Gutzmann
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
| | - Jaxon J Kramer
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
| | - Brigid M Toomey
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
| | - Cory H T Boone
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
| | - Audrey L Atkin
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
| | - Kenneth W Nickerson
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
| |
Collapse
|
7
|
Candida Albicans Virulence Factors and Its Pathogenicity. Microorganisms 2021; 9:microorganisms9040704. [PMID: 33805377 PMCID: PMC8065973 DOI: 10.3390/microorganisms9040704] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 03/22/2021] [Accepted: 03/25/2021] [Indexed: 12/15/2022] Open
Abstract
Candida albicans lives as commensal on the skin and mucosal surfaces of the genital, intestinal, vaginal, urinary, and oral tracts of 80% of healthy individuals [...].
Collapse
|