The Bioinformatics and Molecular approach Es for identification of novel drug targets against the human fungal pathogen Aspergillus fumigatus

Ref ID: 19513

Author:

S Malek Zadeh1,2*, S Sardari1, V Khalaj2

Author address:

1Bioinformatics and Drug Design Group, Pasteur Institute of Iran, Tehran, Iran
2Medical Biotechnology, Pasteur Institute of Iran, Tehran, Iran

Full conference title:

6th Advances Against Aspergillosis 2014

Abstract:

Purpose:
Aspergillus fumigatus is currently the most significant air-born fungal pathogen and the leading cause
of invasive aspergillosis (~85% of cases). Despite the introduction of new effective antifungals,
the mortality rate of invasive aspergillosis still exceeds 40%. Moreover, the emergence of drug
resistance adds more complications to the treatment process. Hence, new antifungal agents are
urgently required. So finding novel targets against Aspergillus fumigatus was our purpose.
Methods:
First of all, Bioinformatics tools have been used in this study to compare whole proteomes of two
organisms, A. fumigatus as a human pathogen with yeast Saccharomyces cerevisiae. Afterwards,
the RBP gene was discriminated for knocking down and evaluating by RNAi and Homologous
recombination methods. Finally, MIC test has applied for comparing mutant and wild strains.
Results:
Based on the LAST alignment of whole proteomes (9,630 proteins), 474 unique proteins were
recognized for A. fumigatus as the homologous of these proteins did not exist in S. cerevisiae.
All of the 474 proteins were considered by the following databases: KEGG, NCBI, EXPASY and
EBI. Functions of 161 proteins have been explained and their accession numbers are available.
Finally, 50 proteins were selected from 161 proteins, these proteins have been annotated, their
functions exist and also only belong to fungi. AfuRbp deletion fragment was used for transformation
of A. fumigatus (akuAKU80 pyrG-) protoplasts. Primary screening of transfromants using PCR
demonstrated that 3 out of 10 colonies were deletants. RT-PCR analysis on these deletion strains
confirmed that AfuRbp does not express in these mutants (data not shown). One of these deletion
mutants was selected and subjected to further analysis. The growth phenotype of this mutant was
examined in various media containing different carbon and nitrogen sources and the results showed
no significant difference between this strain and the parental strain (data not shown). This indicates
that AfuRbp is not essential for growth of A. fumigatus under tested condition. However, MIC tests
with Juglone, Phenylglyoxal, Cyclosporine A (CYC) and FK506 have shown significant sensivity
in mutant strain.
Conclusion:
Our alignment has demonstrated the group of genes that are specific and may be essential in
A. fumigatus. In this study, we evaluated RBP protein by bioinformatics approach as a sample from
fifty proteins that were obtained by comparative alignment. The RBP protein was annotated as a
PPIs enzyme family. So this was seemed a proper target. For analyzing the RBP three inhibitors
selected and synthesized and MIC tests were done with this inhibitors and wild together with mutant
strains. Mutant strains that were used in this study did not have the RBP protein with RNAi and
Homology recombination methods. According to gained results of MIC tests, evaluating the RBP
protein was successful but it was not essential for A. fumigatus. Maybe it can be deduced that the
RNA Binding Protein plays mediate role in a significant pathway with other gene or genes. Thus,
as for the obtained results, the RBP possibly not proper target for drug discovery. Moreover, other
remains forty nine proteins can suitable target for future studies.

Abstract Number: 41

Conference Year: 2014

Link to conference website: http://www.AAA2014.org

New link: NULL

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