Affiliation:
1. Department of Medicine, Thoracic Diseases Research Unit, Mayo Clinic, Rochester, Minnesota, USA
2. Department of Biochemistry, Thoracic Diseases Research Unit, Mayo Clinic, Rochester, Minnesota, USA
Abstract
ABSTRACT
Pneumocystis
cyst life forms contain abundant β-glucan carbohydrates, synthesized using β-1,3 and β-1,6 glucan synthase enzymes and the donor uridine diphosphate (UDP)-glucose. In yeast, phosphoglucomutase (PGM) plays a crucial role in carbohydrate metabolism by interconverting glucose 1-phosphate and glucose 6-phosphate, a vital step in UDP pools for β-glucan cell wall formation. This pathway has not yet been defined in
Pneumocystis
. Herein, we surveyed the
Pneumocystis jirovecii
and
Pneumocystis murina
genomes, which predicted a homolog of the
Saccharomyces cerevisiae
major PGM enzyme. Furthermore, we show that PjPgm2p and PmPgm2p function similarly to the yeast counterpart. When both
Pneumocystis pgm2
homologs are heterologously expressed in
S. cerevisiae pgm2Δ
cells, both genes can restore growth and sedimentation rates to wild-type levels. Additionally, we demonstrate that yeast
pgm2Δ
cell lysates expressing the two
Pneumocystis pgm2
transcripts individually can restore PGM activities significantly altered in the yeast
pgm2Δ
strain. The addition of lithium, a competitive inhibitor of yeast PGM activity, significantly reduces PGM activity. Next, we tested the effects of lithium on
P. murina
viability
ex vivo
and found the compound displays significant anti-
Pneumocystis
activity. Finally, we demonstrate that a para-aryl derivative (ISFP10) with known inhibitory activity against the
Aspergillus fumigatus
PGM protein and exhibiting 50-fold selectivity over the human PGM enzyme homolog can also significantly reduce Pmpgm2 activity
in vitro
. Collectively, our data genetically and functionally validate phosphoglucomutases in both
P. jirovecii
and
P. murina
and suggest the potential of this protein as a selective therapeutic target for individuals with
Pneumocystis
pneumonia.
Funder
HHS | National Institutes of Health
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Pharmacology (medical),Pharmacology