Transcriptomics in human blood incubation reveals the importance of oxidative stress response in Saccharomyces cerevisiae clinical strains.
BACKGROUND
In recent years an increasing number of yeast infections in humans have been related to certain clinical isolates of Saccharomyces cerevisiae. Some clinical strains showed in vivo and in vitro virulence traits and were able to cause death in mice whereas other clinical strains were avirulent.


RESULTS
In this work, we studied the transcriptional profiles of two S. cerevisiae clinical strains showing virulent traits and two control non-virulent strains during a blood incubation model and detected a specific transcriptional response of clinical strains. This response involves an mRNA levels increase of amino acid biosynthesis genes and especially oxidative stress related genes. We observed that the clinical strains were more resistant to reactive oxygen species in vitro. In addition, blood survival of clinical isolates was high, reaching similar levels to pathogenic Candida albicans strain. Furthermore, a virulent strain mutant in the transcription factor Yap1p, unable to grow in oxidative stress conditions, presented decreased survival levels in human blood compared with the wild type or YAP1 reconstituted strain.


CONCLUSIONS
Our data suggest that this enhanced oxidative stress response in virulent clinical isolates, presumably induced in response to oxidative burst from host defense cells, is important to increase survival in human blood and can help to infect and even produce death in mice models.
Instituto de Agroquímica y Tecnología de los Alimentos, IATA-CSIC, Burjassot, Spain.
Silvia
S
Llopis
Amparo
A
Querol
Antje
A
Heyken
Bernhard
B
Hube
Lene
L
Jespersen
M Teresa
MT
Fernández-Espinar
Roberto
R
Pérez-Torrado
D000596:Amino Acids / Q000096:biosynthesis; D001769:Blood / Q000382:microbiology*; D015966:Gene Expression Regulation, Fungal; D006801:Humans; D018384:Oxidative Stress; D012331:RNA, Fungal / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D059467:Transcriptome; D014774:Virulence
D000596:Amino Acids; D012331:RNA, Fungal; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C086677:YAP1 protein, S cerevisiae