Genetic validation of Aspergillus fumigatus phosphoglucomutase as a viable therapeutic target in invasive aspergillosis

TY - JOUR

T1 - Genetic validation of Aspergillus fumigatus phosphoglucomutase as a viable therapeutic target in invasive aspergillosis

AU - Yan, Kaizhou

AU - Stanley, Mathew

AU - Kowalski, Bartosz

AU - Raimi, Olawale

AU - Ferenbach, Andrew

AU - Wei, Pingzhen

AU - Fang, Wenxia

AU - van Aalten, Daan

N1 - This work was funded by an MRC Programme Grant (V001094) and a Wellcome Trust Collaborative Award (200208) to D.M.F.v.A. K.Y. was funded by the China Scholarship Council. W.F. was supported by National Natural Science Foundation of China (31960032). The authors would like to thank Diamond Light Source and European Synchrotron Radiation Facility for beam time. The authors would also like to thank Mr Huijie Yuan for making sequence alignments.

PY - 2022/6

Y1 - 2022/6

N2 - Aspergillus fumigatus is the causative agent of invasive aspergillosis, an infection with mortality rates of up to 50%. The glucan-rich cell wall of A. fumigatus is a protective structure that is absent from human cells and is a potential target for antifungal treatments. Glucan is synthesized from the donor uridine diphosphate glucose, with the conversion of glucose-6-phosphate to glucose-1-phosphate by the enzyme phosphoglucomutase (PGM) representing a key step in its biosynthesis. Here, we explore the possibility of selectively targeting A. fumigatus PGM (AfPGM) as an antifungal treatment strategy. Using a promoter replacement strategy, we constructed a conditional pgm mutant and revealed that pgm is required for A. fumigatus growth and cell wall integrity. In addition, using a fragment screen, we identified the thiol-reactive compound isothiazolone fragment of PGM as targeting a cysteine residue not conserved in the human ortholog. Furthermore, through scaffold exploration, we synthesized a para-aryl derivative (ISFP10) and demonstrated that it inhibits AfPGM with an IC 50 of 2 μM and exhibits 50-fold selectivity over the human enzyme. Taken together, our data provide genetic validation of PGM as a therapeutic target and suggest new avenues for inhibiting AfPGM using covalent inhibitors that could serve as tools for chemical validation.

AB - Aspergillus fumigatus is the causative agent of invasive aspergillosis, an infection with mortality rates of up to 50%. The glucan-rich cell wall of A. fumigatus is a protective structure that is absent from human cells and is a potential target for antifungal treatments. Glucan is synthesized from the donor uridine diphosphate glucose, with the conversion of glucose-6-phosphate to glucose-1-phosphate by the enzyme phosphoglucomutase (PGM) representing a key step in its biosynthesis. Here, we explore the possibility of selectively targeting A. fumigatus PGM (AfPGM) as an antifungal treatment strategy. Using a promoter replacement strategy, we constructed a conditional pgm mutant and revealed that pgm is required for A. fumigatus growth and cell wall integrity. In addition, using a fragment screen, we identified the thiol-reactive compound isothiazolone fragment of PGM as targeting a cysteine residue not conserved in the human ortholog. Furthermore, through scaffold exploration, we synthesized a para-aryl derivative (ISFP10) and demonstrated that it inhibits AfPGM with an IC 50 of 2 μM and exhibits 50-fold selectivity over the human enzyme. Taken together, our data provide genetic validation of PGM as a therapeutic target and suggest new avenues for inhibiting AfPGM using covalent inhibitors that could serve as tools for chemical validation.

KW - Aspergillus fumigatus

KW - phosphoglucomutase

KW - covalent inhibitor

KW - isothiazolone

KW - antifungal

KW - fragment

KW - FBDD

UR - https://www.scopus.com/pages/publications/85131444090

U2 - 10.1016/j.jbc.2022.102003

DO - 10.1016/j.jbc.2022.102003

M3 - Article

C2 - 35504355

SN - 0021-9258

VL - 298

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

IS - 6

M1 - 102003

ER -