DrDaniel Kiboi

Chemotherapy remains central in the control of malaria. However, this approach is hampered by the ability malaria parasite to rapidly developed resistance against antimalarial drugs. To counterbalance this problem, not only should new drugs be developed, but the resistance mechanisms to existing drugs need to be fully understood. For instance, the combination of lumefantrine (LM) and artemether (ATM), has become the first line treatment for malaria in many African countries (including Kenya), and piperaquine (PQ)/dihydroartemisinin (DHA) has reached phase III/IV clinical evaluation as alternative treatment in Africa. However, there is concern that resistance to LM and PQ will be selected relatively quickly. To study the mechanism of resistance to LM, and PQ, we have used rodent parasite Plasmodium berghei as surrogate to Plasmodium falciparum. As part of previous studies, we selected LM and PQ- resistant P. berghei ANKA lines by in vivo drug pressure, we have also confirmed that the mechanisms are heritable in mosquito vectors. Studies show that mode of action of PQ and LM may be similar to that of CQ, thus they may share similar resistance mechanisms. Consequently, we propose to investigate the role of CQ (and quinoline drugs) resistance genes by; i) PCR amplification and sequencing of multi-drug resistance gene-1 (mdr-1), deubiquitinating enzymes 1 (ubp-1) and chloroquine resistance transporter (crt); ii) assessing expression profiles of regulatory genes, mdr-1, glutathione-S-transferase (gst), -glutamyl-cysteine synthetase (ggcs), V-type/H+ pyrophosphatase-2 (VP2) and Ca2+/H+ antiporter (VCX-1) by RT-PCR. The aforementioned genes may not necessarily be associate with LM and PQ resistance, thus in collaboration with Malaria Group at Wellcome Trust Sanger Institute, UK, we will sequence whole genomes of the dilution cloned resistant parasite using next sequencing generation sequencer Illumina Sequencing Technology to identify point mutation in novel genes to identify single nucleotide polymorphisms and copy number variation that have accumulated during drug selection process. This study aims to identify LM and PQ resistance genes in P. berghei, a first step towards understanding the mechanisms of resistance to these drugs in P. falciparum.