Treatment of Pneumocystis carinii pneumonia with 1,3-beta-glucan synthesis inhibitors.

Schmatz, Dennis M.; Romancheck, M. A.; Pittarelli, L A; Schwartz, Robert E.; Fromtling, Robert A.; Nollstadt, K; Vanmiddlesworth, Frank; Wilson, Ken; Turner, Mervyn J.

doi:10.1073/pnas.87.15.5950

Cited by 152 publications

(107 citation statements)

References 33 publications

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“…Cell extracts were prepared from mutant and wild-type cells grown to logarithmic phase as previously described (23). Assays of 1,3-␤-glucan synthase (8,43) and chitin synthase (24) were performed as previously described (16). A published procedure (23) for the preparation of soluble and insoluble membrane fractions was used.…”

Section: Methodsmentioning

confidence: 99%

“…Nikkomycins and polyoxins are competitive inhibitors of chitin synthases (7,10,11,18). Papulacandin B (2,30,43,48), aculeacin A (29,49), echinocandin B (46), and pneumocandin B 0 (6) inhibit synthesis of 1,3-␤-glucan, most likely by inhibiting activity of 1,3-␤-glucan synthase. The killer toxin of Hansenula mrakii kills sensitive strains of S. cerevisiae by inhibiting 1,3-␤-glucan synthase activity (25,50).…”

mentioning

confidence: 99%

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Cloning and characterization of GNS1: a Saccharomyces cerevisiae gene involved in synthesis of 1,3-beta-glucan in vitro

El-Sherbeini

Clemas

1995

J Bacteriol

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The GNS1 gene product is required for the synthesis of 1,3-␤-glucan in vitro, since mutations in this gene result in exhibit an 80 to 90% reduction in 1,3-␤-glucan synthase specific activity. gns1 mutant strains display a pleiotropic phenotype including resistance to a pneumocandin B 0 analog (L-733,560), slow growth, and mating and sporulation defects. The gns1-1 mutation was genetically mapped to within 1.35 centimorgans from the MAT locus on chromosome III. The wild-type GNS1 gene was isolated by complementing the pneumocandin resistance phenotype of the gns1-1 mutation and by hybridization with a chromosome III-derived sequence being used as a probe. The nucleotide sequence of GNS1 was determined and compared with the homologous region of the chromosome. The genetic and nucleotide sequence analyses revealed that GNS1 and the open reading frame, YCR34 [S. Oliver, Q. van der Aart, M. Agostoni-Carbone, and the Chromosome III Sequencing Group, Nature (London) 357:38-46, 1992], represent identical loci in the genome. Cells deleted for GNS1 are viable but exhibit slow growth as well as the pleiotropic phenotype of the gns1 mutants. The putative protein product is predicted to be an integral membrane protein with five transmembrane helices displaying an exoplasmic orientation for the N terminus and a cytoplasmic orientation for the C terminus. This protein may be a subunit of 1,3-␤-glucan synthase.

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Cloning and characterization of GNS1: a Saccharomyces cerevisiae gene involved in synthesis of 1,3-beta-glucan in vitro

El-Sherbeini

Clemas

1995

J Bacteriol

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“…To accomplish this, we employed the rat Pc pneumonia model that has been used extensively to analyze drug activity against the organism (6,60,61). Due to limited drug supply, we treated the rats with nikkomycin Z by oral gavage after establishment of fulminate PCP by immune suppressing rats with corticosteroids and inoculating with Pc.…”

Section: Efficacy Of the Inhibitor Nikkomycin Z In The Rat Model Ofmentioning

confidence: 99%

Characterization of N-Acetylglucosamine Biosynthesis in Pneumocystis species. A New Potential Target for Therapy

Kottom

Hebrink

Jenson

et al. 2017

Am J Respir Cell Mol Biol

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N-acetylglucosamine (GlcNAc) serves as an essential structural sugar on the cell surface of organisms. For example, GlcNAc is a major component of bacterial peptidoglycan, it is an important building block of fungal cell walls, including a major constituent of chitin and mannoproteins, and it is also required for extracellular matrix generation by animal cells. Herein, we provide evidence for a uridine diphospho (UDP)-GlcNAc pathway in Pneumocystis species. Using an in silico search of the Pneumocystis jirovecii and P. murina (Pm) genomic databases, we determined the presence of at least four proteins implicated in the Saccharomyces cerevisiae UDP-GlcNAc biosynthetic pathway. These genes, termed GFA1, GNA1, AGM1, and UDP-GlcNAc pyrophosphorylase (UAP1), were either confirmed to be present in the Pneumocystis genomes by PCR, or, in the case of Pm uap1 (Pmuap1), functionally confirmed by direct enzymatic activity assay. Expression analysis using quantitative PCR of Pneumocystis pneumonia in mice demonstrated abundant expression of the Pm uap1 transcript. A GlcNAc-binding recombinant protein and a novel GlcNAc-binding immune detection method both verified the presence of GlcNAc in P. carinii (Pc) lysates. Studies of Pc cell wall fractions using highperformance gas chromatography/mass spectrometry documented the presence of GlcNAc glycosyl residues. Pc was shown to synthesize GlcNAc in vitro. The competitive UDP-GlcNAc substrate synthetic inhibitor, nikkomycin Z, suppressed incorporation of GlcNAc by Pc preparations. Finally, treatment of rats with Pneumocystis pneumonia using nikkomycin Z significantly reduced organism burdens. Taken together, these data support an important role for GlcNAc generation in the cell surface of Pneumocystis organisms.

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“…Other fungi such as Aspergillus nidulans and Candida albicans alter gene expression as an adaptive response to environmental pH changes in order to maintain cell wall integrity and promote viability under various conditions (6,11,21,23,(32)(33)(34)(35). Specifically, it has been demonstrated that C. albicans expresses a unique family of pH-regulated genes required for virulence.…”

mentioning

confidence: 99%

Characterization ofPneumocystis carinii PHR1, a pH-Regulated Gene Important for Cell Wall Integrity

Kottom¹,

Thomas²,

Limper

2001

J Bacteriol

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Pneumocystis carinii remains an important opportunistic fungal pathogen causing life-threatening pneumonia in patients with AIDS and malignancy. Currently, little is known about how the organism adapts to environmental stresses and maintains its cellular integrity. We recently discovered an open reading frame approximately 600 bp downstream of the region coding GSC-1, a gene mediating ␤-glucan cell wall synthesis in P. carinii. The predicted amino acid sequence of this new gene, termed P. carinii PHR1, exhibited 38% homology to Saccharomyces cerevisiae GAS1, a glycosylphosphatidylinositol-anchored protein essential to maintaining cell wall integrity, and 37% homology to Candida albicans PHR1/PHR2, pH-responsive genes encoding proteins recently implicated in cross-linking ␤-1,3-and ␤-1,6-glucans. In view of its homology to these related fungal genes, the pH-dependent expression of P. carinii PHR1 was examined. As in C. albicans, P. carinii PHR1 expression was repressed under acidic conditions but induced at neutral and more alkaline pH. PHR1-related proteins have been implicated in glucan cell wall stability under various environmental conditions. Although difficulties with P. carinii culture and transformation have traditionally limited assessment of gene function in the organism itself, we have successfully used heterologous expression of P. carinii genes in related fungi to address functional correlates of P. carinii-encoded proteins. Therefore, the potential role of P. carinii PHR1 in cell wall integrity was examined by assessing its ability to rescue an S. cerevisiae gas1 mutant with absent endogenous Phr1p-like activity. Interestingly, P. carinii PHR1 DNA successfully restored proliferation of S. cerevisiae gas1 mutants under lethal conditions of cell wall stress. These results indicate that P. carinii PHR1 encodes a protein responsive to environmental pH and capable of mediating fungal cell wall integrity.Pneumocystis carinii remains an important fungal agent causing life-threatening pneumonia in patients with impaired immunity (19). Other fungi such as Aspergillus nidulans and Candida albicans alter gene expression as an adaptive response to environmental pH changes in order to maintain cell wall integrity and promote viability under various conditions (6,11,21,23,(32)(33)(34)(35). Specifically, it has been demonstrated that C. albicans expresses a unique family of pH-regulated genes required for virulence. These genes nominally include PHR1, a gene expressed maximally at pH 5.5 to 8.0 which encodes a protein promoting systemic infection of mice. Alternatively, C. albicans also expresses PHR2, whose transcription is greatest at acidic pH (4 to 5) values (24). If PHR2 is rendered inactive, C. albicans mutants exhibit decreased pathogenesis in a mouse model of vaginal infection (6,24,32).Recent studies indicate that Phr1p and Phr2p act on ␤-1,3-glucans of the C. albicans cell walls, elongating the ␤-1,3 polysaccharide backbone and potentially mediating the attachment of ␤-1,6 glucosyl side chains and ␤-1,6-...

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Treatment of Pneumocystis carinii pneumonia with 1,3-beta-glucan synthesis inhibitors.

Cited by 152 publications

References 33 publications

Cloning and characterization of GNS1: a Saccharomyces cerevisiae gene involved in synthesis of 1,3-beta-glucan in vitro

Cloning and characterization of GNS1: a Saccharomyces cerevisiae gene involved in synthesis of 1,3-beta-glucan in vitro

Characterization of N-Acetylglucosamine Biosynthesis in Pneumocystis species. A New Potential Target for Therapy

Characterization ofPneumocystis carinii PHR1, a pH-Regulated Gene Important for Cell Wall Integrity

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