Melioidosis, a highly virulent disease caused by infection of the soil-borne bacterium Burkholderia pseudomallei, is currently and voraciously expanding its geographical dominion from the general propinquity of southeast Asia and northern Australia1 to adjacent regions of the world due to the glaring absence of efficacious therapies, namely antibiotics. Hcp1, a protein involved in the secretion system (Type VI) of the organism as either a translocator or effector macromolecule2, is therein implicated in the intrinsic perniciousness of B. pseudomallei.3 Hcp1 then, represents a feasible and promising target for aptamer selection, as inhibition of the bacterial secretion mechanisms which undergird the persistence of the infection would have the potential to devastate entire colonies and extinguish the pathogen altogether.
The specific aims of this proposal involve the isolation of a specific, anti-Hcp1 binding aptamer sequence for therapeutic utility, and, as more of an extant potentiality, the application of this aptamer to a population of B. pseudomallei in vitro for the determination of the specific function of HCP1 and additionally to afford greater insight into the functional nature of Type VI bacterial secretion systems (T6SS).
Figure 1: Explication of basic methodological progression from initial selection rounds to latent applications of derived anti-Hcp1 aptamer.
In effect, the goal of this proposal is to select an aptamer that binds with high affinity to HCP1, a protein directly involved in the lethality of B. pseudomallei, the causative agent of melioidosis, in order to offer an alternative to the currently inadequate repertoire of therapeutic methods persisting in melioidosis-affected areas of the world. Additionally, application of this aptamer within the realm of basic science may cast further comprehension upon the nature of T6SS and the specific, now speculative, role occupied by the proteins endemic to them, specifically, Hcp1.
1. Mongkol Vesaratchavest et. al, Nonrandom Distribution of Burkholderia pseudomallei Clones in Relation to Geographical Location and Virulence J. Clin. Microbiol., Jul 2006; 44: 2553 - 2557.
2. Bingle, Lewis et. al. Type VI secretion: a beginner’s guide Curr. Op. in Microbiol., February 2008, 11(1): 3 - 8.
3. Schell, Mark A. et. al. Type VI secretion is major virulence determinant in Burkholderia mallei Mol. Micro., 2007, 64(8): 1466 - 1485