10.25442/HKU.20752324.V1
Walton Man To Chan
Walton Man To
Chan
University of Hong Kong
Walton Chan
Walton
Chan
0000-0003-0909-8414
Supporting data for "Role of Candida auris Extracellular Vesicles in Pathogenesis and Treatment"
<p> <strong>“The role of </strong><em><strong>Candida auris </strong></em><strong>extracellular vesicles on pathogenesis and treatment”</strong></p>
<p>Submitted by</p>
<p><strong>Walton Man To Chan</strong></p>
<p>for the degree of Master of Philosophy</p>
<p>at the University of Hong Kong</p>
<p>in August 2022</p>
<p><em>Candida auris</em> is an emergent pathogenic fungus prominently known for its unusual transmissibility, environmental persistence, and multidrug resistance. It is the only fungi to be listed in the highest priority for the American Centers for Disease Control’s Antimicrobial Resistance Threats List. Until now, few of its known antifungal resistance mechanisms could adequately explain differences in survival <em>in vitro </em>and <em>in vivo </em>when challenged with antifungal drugs. Therefore, research into phenotypic survival mechanisms for <em>C. auris </em>was undertaken.</p>
<p>Here, naturally produced nanometer-sized secreted particles known as extracellular vesicles (EVs) are shown to play a key role in attenuating the potency of the essential frontline drug, amphotericin B. In <em>in vitro </em>assays, these EVs acted in a dose-dependent manner, with nanogram levels of them capable of doubling the minimum inhibitory concentration needed to kill the yeast. The results were reproducible in drastically different clinical formulations of the drug as well, suggesting a possible clinical translation to the research. Furthermore, this effect proved reproducible and transferable among isolates of <em>C. auris</em>, though could not be replicated in other pathogenic fungi such as <em>Candida albicans</em>. Chemical ablation of EV endocytosis restored wild-type susceptibility towards the drug in the face of EV treatment. Proteomic analysis of <em>C. auris </em>EVs revealed the abundance of an uncharacterized protein suspected to have glucanase activity. Its nearest homologue in <em>C. albicans </em>revealed potential functions in both dampening immune responses and biofilm catalysing ability. Quantification of <em>C. auris </em>EVs incubated with amphotericin B suggested that EVs likely were not inducing resistance through reducing bioavailability. </p>
<p>Together, these results reveal extracellular vesicles to likely be a novel and unique mechanism for the pathogenic yeast <em>C. auris </em>to evade amphotericin B treatment. Successful inhibition of this process restored wild-type susceptibility and provide justification for research into synergies between EV-inhibiting and existing antifungal drugs. Further research will be required to detail the exact mechanism in which <em>C. auris </em>EVs confer resistance against amphotericin B, and whether these results can be clinically translated. </p>
<p>- An abstract of 328 words</p>
<p> </p>
Medical bacteriology
Medical mycology
HKU Data Repository
2022
2022-11-22
2022-11-22
Dataset
3397553924 Bytes
10.25442/hku.20752324
CC BY-NC 4.0