A variant ECE1 allele contributes to reduced pathogenicity of Candida albicans during vulvovaginal candidiasis

Junyan Liu; Hubertine M. E. Willems; Emily A. Sansevere; Stefanie Allert; Katherine S. Barker; David J. Lowes; Andrew C. Dixson; Zhenbo Xu; Jian Miao; Christian Dejarnette; Helene Tournu; Glen E. Palmer; Jonathan P. Richardson; Francisco N. Barrera; Bernhard Hube; Julian R. Naglik; Brian M. Peters; Robert T. Wheeler

doi:10.1371/journal.ppat.1009884

A variant ECE1 allele contributes to reduced pathogenicity of Candida albicans during vulvovaginal candidiasis

Junyan Liu, Hubertine M. E. Willems, Emily A. Sansevere, Stefanie Allert, Katherine S. Barker, David J. Lowes, Andrew C. Dixson, Zhenbo Xu, Jian Miao, Christian Dejarnette, Helene Tournu, Glen E. Palmer, Jonathan P. Richardson, Francisco N. Barrera, Bernhard Hube, Julian R. Naglik, Brian M. Peters, Robert T. Wheeler

Centre for Host Microbiome Interactions

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40 Citations (Scopus)

Abstract

Vulvovaginal candidiasis (VVC), caused primarily by the human fungal pathogen Candida albicans, results in significant quality-of-life issues for women worldwide. Candidalysin, a toxin derived from a polypeptide (Ece1p) encoded by the ECE1 gene, plays a crucial role in driving immunopathology at the vaginal mucosa. This study aimed to determine if expression and/or processing of Ece1p differs across C. albicans isolates and whether this partly underlies differential pathogenicity observed clinically. Using a targeted sequencing approach, we determined that isolate 529L harbors a similarly expressed, yet distinct Ece1p isoform variant that encodes for a predicted functional candidalysin; this isoform was conserved amongst a collection of clinical isolates. Expression of the ECE1 open reading frame (ORF) from 529L in an SC5314-derived ece1Δ/Δ strain resulted in significantly reduced vaginopathogenicity as compared to an isogenic control expressing a wild-type (WT) ECE1 allele. However, in vitro challenge of vaginal epithelial cells with synthetic candidalysin demonstrated similar toxigenic activity amongst SC5314 and 529L isoforms. Creation of an isogenic panel of chimeric strains harboring swapped Ece1p peptides or HiBiT tags revealed reduced secretion with the ORF from 529L that was associated with reduced virulence. A genetic survey of 78 clinical isolates demonstrated a conserved pattern between Ece1p P2 and P3 sequences, suggesting that substrate specificity around Kex2p-mediated KR cleavage sites involved in protein processing may contribute to differential pathogenicity amongst clinical isolates. Therefore, we present a new mechanism for attenuation of C. albicans virulence at the ECE1 locus.

Original language	English
Article number	e1009884
Journal	PLoS Pathogens
Volume	17
Issue number	9
Early online date	10 Sept 2021
DOIs	https://doi.org/10.1371/journal.ppat.1009884
Publication status	Published - 10 Sept 2021

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10.1371/journal.ppat.1009884Licence: CC BY

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Liu, J., Willems, H. M. E., Sansevere, E. A., Allert, S., Barker, K. S., Lowes, D. J., Dixson, A. C., Xu, Z., Miao, J., Dejarnette, C., Tournu, H., Palmer, G. E., Richardson, J. P., Barrera, F. N., Hube, B., Naglik, J. R., Peters, B. M., & Wheeler, R. T. (2021). A variant ECE1 allele contributes to reduced pathogenicity of Candida albicans during vulvovaginal candidiasis. PLoS Pathogens, 17(9), Article e1009884. https://doi.org/10.1371/journal.ppat.1009884

@article{04f7c753455f4dae9d4e7626022b5cae,

title = "A variant ECE1 allele contributes to reduced pathogenicity of Candida albicans during vulvovaginal candidiasis",

abstract = "Vulvovaginal candidiasis (VVC), caused primarily by the human fungal pathogen Candida albicans, results in significant quality-of-life issues for women worldwide. Candidalysin, a toxin derived from a polypeptide (Ece1p) encoded by the ECE1 gene, plays a crucial role in driving immunopathology at the vaginal mucosa. This study aimed to determine if expression and/or processing of Ece1p differs across C. albicans isolates and whether this partly underlies differential pathogenicity observed clinically. Using a targeted sequencing approach, we determined that isolate 529L harbors a similarly expressed, yet distinct Ece1p isoform variant that encodes for a predicted functional candidalysin; this isoform was conserved amongst a collection of clinical isolates. Expression of the ECE1 open reading frame (ORF) from 529L in an SC5314-derived ece1Δ/Δ strain resulted in significantly reduced vaginopathogenicity as compared to an isogenic control expressing a wild-type (WT) ECE1 allele. However, in vitro challenge of vaginal epithelial cells with synthetic candidalysin demonstrated similar toxigenic activity amongst SC5314 and 529L isoforms. Creation of an isogenic panel of chimeric strains harboring swapped Ece1p peptides or HiBiT tags revealed reduced secretion with the ORF from 529L that was associated with reduced virulence. A genetic survey of 78 clinical isolates demonstrated a conserved pattern between Ece1p P2 and P3 sequences, suggesting that substrate specificity around Kex2p-mediated KR cleavage sites involved in protein processing may contribute to differential pathogenicity amongst clinical isolates. Therefore, we present a new mechanism for attenuation of C. albicans virulence at the ECE1 locus.",

author = "Junyan Liu and Willems, {Hubertine M. E.} and Sansevere, {Emily A.} and Stefanie Allert and Barker, {Katherine S.} and Lowes, {David J.} and Dixson, {Andrew C.} and Zhenbo Xu and Jian Miao and Christian Dejarnette and Helene Tournu and Palmer, {Glen E.} and Richardson, {Jonathan P.} and Barrera, {Francisco N.} and Bernhard Hube and Naglik, {Julian R.} and Peters, {Brian M.} and Wheeler, {Robert T.}",

note = "Funding Information: Funding: This work was supported by National Institutes of Health ? NIAID grants K22AI110541, R21AI127942, R21AI141829, and R01A134796 awarded to BMP. Work was also supported by NIGMS grant R01GM120642 awarded to FNB and NIDCR grant R01DE022550 and Wellcome Trust grant 214229_Z_18Z awarded to JRN. Work was also supported in part by the UTHSC College of Pharmacy Center for Pediatric and Experimental Therapeutics (https://www.uthsc.edu/pharmacy/ dcpts/cpet.php). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Publisher Copyright: Copyright: {\textcopyright} 2021 Liu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.",

year = "2021",

month = sep,

day = "10",

doi = "10.1371/journal.ppat.1009884",

language = "English",

volume = "17",

journal = "PLoS Pathogens",

issn = "1553-7366",

publisher = "Public Library of Science",

number = "9",

}

Liu, J, Willems, HME, Sansevere, EA, Allert, S, Barker, KS, Lowes, DJ, Dixson, AC, Xu, Z, Miao, J, Dejarnette, C, Tournu, H, Palmer, GE, Richardson, JP, Barrera, FN, Hube, B, Naglik, JR, Peters, BM & Wheeler, RT 2021, 'A variant ECE1 allele contributes to reduced pathogenicity of Candida albicans during vulvovaginal candidiasis', PLoS Pathogens, vol. 17, no. 9, e1009884. https://doi.org/10.1371/journal.ppat.1009884

TY - JOUR

T1 - A variant ECE1 allele contributes to reduced pathogenicity of Candida albicans during vulvovaginal candidiasis

AU - Liu, Junyan

AU - Willems, Hubertine M. E.

AU - Sansevere, Emily A.

AU - Allert, Stefanie

AU - Barker, Katherine S.

AU - Lowes, David J.

AU - Dixson, Andrew C.

AU - Xu, Zhenbo

AU - Miao, Jian

AU - Dejarnette, Christian

AU - Tournu, Helene

AU - Palmer, Glen E.

AU - Richardson, Jonathan P.

AU - Barrera, Francisco N.

AU - Hube, Bernhard

AU - Naglik, Julian R.

AU - Peters, Brian M.

AU - Wheeler, Robert T.

N1 - Funding Information: Funding: This work was supported by National Institutes of Health ? NIAID grants K22AI110541, R21AI127942, R21AI141829, and R01A134796 awarded to BMP. Work was also supported by NIGMS grant R01GM120642 awarded to FNB and NIDCR grant R01DE022550 and Wellcome Trust grant 214229_Z_18Z awarded to JRN. Work was also supported in part by the UTHSC College of Pharmacy Center for Pediatric and Experimental Therapeutics (https://www.uthsc.edu/pharmacy/ dcpts/cpet.php). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Publisher Copyright: Copyright: © 2021 Liu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

PY - 2021/9/10

Y1 - 2021/9/10

N2 - Vulvovaginal candidiasis (VVC), caused primarily by the human fungal pathogen Candida albicans, results in significant quality-of-life issues for women worldwide. Candidalysin, a toxin derived from a polypeptide (Ece1p) encoded by the ECE1 gene, plays a crucial role in driving immunopathology at the vaginal mucosa. This study aimed to determine if expression and/or processing of Ece1p differs across C. albicans isolates and whether this partly underlies differential pathogenicity observed clinically. Using a targeted sequencing approach, we determined that isolate 529L harbors a similarly expressed, yet distinct Ece1p isoform variant that encodes for a predicted functional candidalysin; this isoform was conserved amongst a collection of clinical isolates. Expression of the ECE1 open reading frame (ORF) from 529L in an SC5314-derived ece1Δ/Δ strain resulted in significantly reduced vaginopathogenicity as compared to an isogenic control expressing a wild-type (WT) ECE1 allele. However, in vitro challenge of vaginal epithelial cells with synthetic candidalysin demonstrated similar toxigenic activity amongst SC5314 and 529L isoforms. Creation of an isogenic panel of chimeric strains harboring swapped Ece1p peptides or HiBiT tags revealed reduced secretion with the ORF from 529L that was associated with reduced virulence. A genetic survey of 78 clinical isolates demonstrated a conserved pattern between Ece1p P2 and P3 sequences, suggesting that substrate specificity around Kex2p-mediated KR cleavage sites involved in protein processing may contribute to differential pathogenicity amongst clinical isolates. Therefore, we present a new mechanism for attenuation of C. albicans virulence at the ECE1 locus.

AB - Vulvovaginal candidiasis (VVC), caused primarily by the human fungal pathogen Candida albicans, results in significant quality-of-life issues for women worldwide. Candidalysin, a toxin derived from a polypeptide (Ece1p) encoded by the ECE1 gene, plays a crucial role in driving immunopathology at the vaginal mucosa. This study aimed to determine if expression and/or processing of Ece1p differs across C. albicans isolates and whether this partly underlies differential pathogenicity observed clinically. Using a targeted sequencing approach, we determined that isolate 529L harbors a similarly expressed, yet distinct Ece1p isoform variant that encodes for a predicted functional candidalysin; this isoform was conserved amongst a collection of clinical isolates. Expression of the ECE1 open reading frame (ORF) from 529L in an SC5314-derived ece1Δ/Δ strain resulted in significantly reduced vaginopathogenicity as compared to an isogenic control expressing a wild-type (WT) ECE1 allele. However, in vitro challenge of vaginal epithelial cells with synthetic candidalysin demonstrated similar toxigenic activity amongst SC5314 and 529L isoforms. Creation of an isogenic panel of chimeric strains harboring swapped Ece1p peptides or HiBiT tags revealed reduced secretion with the ORF from 529L that was associated with reduced virulence. A genetic survey of 78 clinical isolates demonstrated a conserved pattern between Ece1p P2 and P3 sequences, suggesting that substrate specificity around Kex2p-mediated KR cleavage sites involved in protein processing may contribute to differential pathogenicity amongst clinical isolates. Therefore, we present a new mechanism for attenuation of C. albicans virulence at the ECE1 locus.

UR - http://www.scopus.com/inward/record.url?scp=85114773221&partnerID=8YFLogxK

U2 - 10.1371/journal.ppat.1009884

DO - 10.1371/journal.ppat.1009884

M3 - Article

SN - 1553-7366

VL - 17

JO - PLoS Pathogens

JF - PLoS Pathogens

IS - 9

M1 - e1009884

ER -

A variant ECE1 allele contributes to reduced pathogenicity of Candida albicans during vulvovaginal candidiasis

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