Effects of Targeted Organ Specific Knockdown of Multi Drug Resistance Protein-1 on Lipid, Carbohydrate Levels and Feeding Patterns of Drosophila melanogaster

Abstract

Multi-resistance proteins (ABC) transporters are known to control the passage of several important metabolic substances and drugs in the body tightly fused with glutathione as organic anions. These transporters are the most dominant link with multidrug resistance (MDR) and antibacterial resistance mechanisms in the body. MRP1 is a ubiquitously expressed multitasking transporter and transports the widest spectrum of substrates among the ABC group of transporters. It is encoded by the ABCC1 gene. Over expression of MRP1 in cancer cells has been known to confer resistance against antineoplastic agents therefore hindering the efforts against cancer and other disease-causing bacteria. In this research and study, I investigated the effect of manipulating by silencing the drosophila melanogaster MRP1 activity in target organ specific manner in the gut, mid gut, malpighian tubules and the fat body by employing the GAL4 -UAS system. This research aimed at determining the effect of aimed organ specific activity of drosophila MRP1 (ABCC1) on carbohydrate, lipid levels and its effect on feeding patterns. In the experimental model where MRP1 was silenced in organ specific manner, drosophila fly stain URO-GAL4 fly strains that are tissue specific for the Malpighian tubes showed a high starvation resistance compared to other strains. Using colorimetric sugar tests, no noteworthy differences were seen in glycogen and trehalose levels in this strain. Moreover, coupled colored triglycerides assays revealed a high lipid level in URO-GAL4 MRP1 mutant flies. Further molecular tests done using qPCR analysis revealed an up -regulation of DHr96 (mammalian NR112) nuclear receptor genes in the URO-GAL4 MRP1 mutant flies. These genes control triglycerides homoeostasis and regulation of carbohydrate metabolic processes in Drosophila melanogaster. The findings suggested that MRP1 knockdown in the malpighian tubules in Drosophila melanogaster whose function mimics‟ the mammalian kidneys has the greatest effect on lipid movement and, MRP1 is highly involved in lipid transport and lipid signaling. This finding will go a long way in facilitating the development of safe, specific MRP1 inhibitors that can target the negative „drug efflux‟ MRP1 activity in mammalian kidneys in this case or other specific organs in a clinical setting. This experimental approach provides a model template to assess human MRP1 and its relevance to antineoplastic drug modeling studies and, the critical roles MRP1 plays in cell biology that set it apart from its long established traditional function as a drug efflux pump.