Expression Analysis of Multiple Genes May Involve in Antimony Resistance among Leishmania major Clinical Isolates from Fars Province, Central Iran.

BACKGROUND: Treatment of Cutaneous Leishmaniasis (CL) is being faced with serious difficulties in Fars Province, due to emerging of resistance against meglumine antimonite (Glucantime®). In this context, determining some biomarkers for drug sensitivity monitoring seems to be highly essential. Different studies have been carried out to decipher the genes might be involved in antimony resistant phenotype in Leishmania spp. Here, we selected three genes: AQP (as drug transporter), TDR-1-1(as drug activator), and γ-GCS (inducing reduction environment) for comparative expression analysis on clinical resistant and sensitive isolates of L. major.

METHODS: The clinical isolates of L. major were collected from CL patients referred to Valfajr Health Center, Shiraz from Oct 2011 to Feb 2012. The susceptibility test was performed to confirm drug sensitivity of strains in vitro as well. Then, the gene expression analysis was performed by quantitative real-time PCR using SYBR® Green.

RESULTS: By comparison of expression level between strains, up regulation of γ-GCS gene and down regulation of AQP gene were observed in resistant strains compared to the sensitive isolates; however, down regulation of AQP was not statistically specific. Analysis of TDR-1-1 gene unexpectedly showed a high level of expression in the non-responsive cases.

CONCLUSION: The γ-GCS, at least, can be considered as a suitable molecular marker for screening antimony sensitivity in clinical isolates, although AQP and TDR-1-1gene seem not to be reliable resistant markers.