The increasing prevalence of obesity is associated with various metabolic diseases such as diabetes, posing significant social and economic burdens to the society. While obesity is a complex disease with multiple factors contributing to its pathophysiology, altered glucose and lipid metabolism is evident in obese patients as well as in animal models. Abnormal metabolic regulation often leads to development of insulin resistance, a hallmark of obesity-induced type 2 diabetes. In this review, we provide a brief overview of altered lipid metabolism manifested in the obese state. In addition, two representative animal models, Mus musculus and Drosophila melanogaster, are presented with experimental approaches adopted for generation and utilization of these models. More specifically, Drosophila has been widely used for studying the core physiological phenomena across phyla for decades, mostly due to the ease of handling and sophisticated genetic manipulations with conserved cell signaling pathways of reduced redundancy. Considering a significant degree of homology in Drosophila for human disease-associated genes, it poses as a versatile in vivo platform to study the pathophysiology of various human diseases. With core metabolic pathways governing energy homeostasis generally conserved, Drosophila can be used as a model for studying molecular mechanisms underlying disease phenotypes manifested in obese and diabetic patients. In this review, we discuss representative Drosophila studies that investigated the effects of dysregulated core signaling pathways on metabolic signatures of obese animals.

MicroRNAs (miRNAs) are a group of small non-coding RNAs consisting of 18~24 nucleotides in length. Each miRNA is expected to bind a few hundreds of putative target mRNAs, thus inhibiting their translation into protein products mostly by degradation of targets. With its biogenesis extensively deciphered, miRNAs have been implicated in a variety of biological processes, including early development and cellular metabolism. In addition, dysregulation of miRNAs and subsequent alterations in the expression of its target molecules are thought to be linked to the pathophysiology of multiple human illnesses, including cancer. To establish the miRNA-target relationships important for developing a specific disease, it is critical to validate the putative targets of each miRNA suggested by computational methods in vivo. In this review, we will first discuss oncogenic and tumor-suppressive roles of miRNAs in human cancer and introduce computational methods to predict putative targets of miRNAs. Then, the value of Drosophila melanogaster as an alternative model system will be further discussed in studying human cancer and in validating the miRNA-target relationships in vivo. Finally, we will present a possibility of applying the mammals-to-Drosophila-to-mammals approach to study the roles of miRNAs and their targets in the pathophysiology of oral cancer, an intractable type of cancer with poor prognosis and survival rate.

The spotted wing drosophila (SWD), Drosophila suzukii, is classified exotic quarantine pest in Australia and EU, soSWD-free must be supported by evidence of surveys and phytosanitary measures in exported host agricultural commoditiesin Korea. From a quarantine control point of view, SWD is importantly considered as model insect pest for exotic fruitflies (Bactrocera dorsalis) in Korea as well because of similarity in ecological cycles. In evaluations of ethyl formate(EF) only and combined cold treatment to kill eggs and larvae of SWD, the combined EF fumigation applied at LCt50%(50% killed lethal concentration X time) and cold treatement (5℃) for > 5 days showed the promise to new conceptfor eradicating quarantine pest and these could be helpful to pre-develop exotic fruit fly management in Korea.

Repetitive applications of drugs to tumor tissues and animals induced resistance and/or tolerances which caused severe problem in agriculture and medicine. However, we still do not clearly understand the molecular and cellular mechanisms underlying development of resistance and tolerance to chemicals. Drosophila is one of the most widely used model for studying fundamental phenomena in sciences using its available genetic and genomic resources. To investigate unknown molecular and cellular basis of drug resistance development, we applied Drosophila with two different concentrations of a chemical after treating them with Ethyl methanesulfonate mutatgenesis. We found that flies treating with two different concentration of chemicals showed different susceptibility to a chemical. We have established two different lines showing different susceptibility to a chemical. We will use these lines to compare any differences in mRNA expression profiling and enzyme activities. (This work was supported by project title: Investigation on cross drug resistance mechanisms using Drosophila as a model (PJ010821032016) from Rural Development Administration).

Alzheimer’s disease (AD) is an age-related neurodegenerative disease characterized by extensive loss of synaptic connections, neuronal death, and the presence of extracellular amyloid plaques and intracellular neurofibrillary tangles (iNFTs). The extracellular amlyoid plaques are mainly composed of the amyloid beta (Aβ) peptide which formed by proteolytic processing of the amyloid precursor protein (APP). Aβ42peptide oligomerizes, is neurotoxic and readily forms aggregates that accumulate in the brain to form plaques. These oligomers are thought to cause inflammation, oxidative stress and apoptosis, thereby resulting in synaptic and neuronal loss. Although AD is neurodegenerative disorder, current therapies designed to treat it still demonstrate limited efficacy. Silkworm (Bombyx mori) has long been used as food and medicine in Asian countries which is reputed for the treatment of numerous neurological disorders including AD. In this study, we use Drosophila melanogaster which is expressed the human AD-associated protein APP695, BACE and MAPT as the model and initially investigate whether silkworm powder food has positive effect on flies expressing Alzheimer’s status as well as makes the improvement in disease condition by using this AD fly model (This work was carried out with the support of the Cooperative Research Program for Agriculture Science & Technology Development (Project title: Elucidation the health improvement effects of boiled silk worm larvae, Project No: PJ01082801) Rural Development Administration)

Exposure to several common acting through oxidation stress environmental toxins has been shown to be associated with Parkinson’s disease (PD). One recently identified inherited Parkinson’s disease (PD) gene, DJ-1, may have a role in protection from oxidative stress, thus potentially linking a genetic cause with critical environmental risk factors [1]. In the present study, initially we assessed the antioxidant activity of Silk Worm Powder (SWP) in selected chemical systems and further explored the efficacy of SWP in Drosophila lacking DJ-1 function (This work was carried out with the support of the Cooperative Research Program for Agriculture Science & Technology Development (Project title: Elucidation the health improvement effects of boiled silk worm larvae, Project No: PJ01082801) Rural Development Administration).