Exploring the Mode of Action of Bioactive Compounds by Microfluidic Transcriptional Profiling in Mycobacteria

10.1371/journal.pone.0069191PLoS ONE87-POLN

List of investigational and FDA approved anti-tubercular drugs and their mode of action.

<p>MIC₅₀ listed for anti-tubercular investigational and SAR compounds, when available.</p

Hierarchical clustering and correlations of anti-tubercular drugs.

<p>Transcriptional responses data obtained from microfluidic experiment are used for the analysis. The detailed descriptions for genes represented in this figure are provided in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069191#pone.0069191.s003" target="_blank">Table S1</a>. (A) Hierarchical clustering via average linkage of Pearson correlations for FDA approved drugs. The individual genes are represented in y-axis and the compound treatment is in the x-axis. (B) Pearson correlations for 23 anti-tubercular drugs. Correlations were calculated between 2 independent microfluidic experiments, following median normalization to account for plate effects.</p

Pathway enrichment of functional classes of genes on PCR array.

<p>Pathway enrichment of functional classes of genes on PCR array.</p

Transcriptional responses of <i>M. bovis</i> BCG to anti-tubercular drugs profiled using qPCR.

<p>A compendium of qPCR results can show differences in the MOA of anti-tubercular drugs. (A) Spatial grouping of drug expression profiles on a dendrogram after qPCR profiling using hierarchical clustering. From the list of drugs tested, two major clusters emerge cell wall inhibitors, and those that inhibit DNA/protein synthesis. (B) Similarity matrix of expression profiles for chemical inhibitors using qPCR profiling. The blue-red color scale shows the degree of correlation of drugs expression profiles ranging from −1 to 1 respectively. ×- depicts transcriptional responses at 2× or 0.5× the MIC₅₀, while those that have no × designation were done 1× the MIC₅₀.</p

Transcriptional responses to drug treatment reveal that a single gene representing logically associated gene clusters is sufficient for MoA diagnosis in <i>Mycobacterium tuberculosis</i>.

<p>Groups of drugs clustered separately based on the known mechanism of action, while SAR series of compounds with novel MoA (cyclomarin) showed a fingerprint distinct from any of the compounds tested. Periods following drug names represent duplicates. X-axis represents the 90 genes that were chosen from the microarray as representative of 90 clusters, y-axis lists the different drug treatments. i, ii, and iii, represent 3 clusters namely, cell wall inhibitor, RNA polymerase inhibitor and Cyclomarin series, respectively.</p