Background: Small interfering RNAs (siRNAs) are known as commonly used targeting
mRNAs tools for suppressing gene expression. Since Signal Transducer and Activator of Transcription
4 (STAT4) is considered as a significant transcription factor for generation and differentiation
of Th1 cells during vascular dysfunction and atherosclerosis, suppressing STAT4 could represent
novel immunomodulatory therapies against atherosclerosis.
Objective: Therefore, the current study was conducted to design efficient siRNAs specific for
STAT4 and to evaluate different criteria affecting their functionality.
Methods: In the present study, all related sequences of STAT4 gene were retrieved from Gen Bank
database. Multiple sequence alignment was carried out to recognize Open Reading Frame (ORF)
and conserved region. Then, siDirect 2.0 server was applied for the development of candidate siRNA
molecules and confirmation of predicted molecules was performed using Dharma siRNA technology
and GeneScript siRNA targetfinder. In addition, BLAST tool was used against whole Genebank
databases to identify potential off-target genes. DNA/RNA GC content calculator and mfold
server were used to calculate GC content and secondary structure prediction of designed siRNA,
respectively. Finally, IntaRNA program was used to study the thermodynamics of interaction between
predicted siRNA and target gene.
Results: Based on the obtained results, three efficient siRNA molecules were designed and validated
for STAT4 gene silencing using computational methods, which may result in suppressing
STAT4 gene expression.
Conclusion: According to our results, this study shows that siRNA targeting STAT4 can be considered
as a therapeutic agent in many Th1-mediated pathologic conditions specially atherosclerosis.