Identification and characterization of GAL4 drivers that mark distinct cell types and regions in the Drosophila adult gut.

The gastrointestinal tract in the adult Drosophila serves as a model system for exploring the mechanisms underlying digestion, absorption and excretion, stem cell plasticity, and inter-organ communication, particularly through the gut-brain axis. It is also useful for studying the cellular and adaptive responses to dietary changes, alterations in microbiota and immunity, and systematic and endocrine signals. Despite the various cell types and distinct regions in the gastrointestinal tract, few tools are available to target and manipulate the activity of each cell type and region, and their gene expression. Here, we report 353 GAL4 lines and several split-GAL4 lines that are expressed in enteric neurons (ENs), progenitors (ISCs and EBs), enterocytes (ECs), enteroendocrine cells (EEs), or/and other cell types that are yet to be identified in distinct regions of the gut. We had initially collected approximately 600 GAL4 lines that may be expressed in the gut based on RNA sequencing data, and then crossed them to UAS-GFP to perform immunohistochemistry to identify those that are expressed selectively in the gut. The cell types and regional expression patterns that are associated with the entire set of GAL4 drivers and split-GAL4 combinations are annotated online at http://kdrc.kr/index.php (K-Gut Project). This GAL4 resource can be used to target specific populations of distinct cell types in the fly gut, and therefore, should permit a more precise investigation of gut cells that regulate important biological processes.

Postprandial sodium sensing by enteric neurons in Drosophila.

Sodium is essential for all living organisms1. Animals including insects and mammals detect sodium primarily through peripheral taste cells2-7. It is not known, however, whether animals can detect this essential micronutrient independently of the taste system. Here, we report that Drosophila Ir76b mutants that were unable to detect sodium2 became capable of responding to sodium following a period of salt deprivation. From a screen for cells required for the deprivation-induced sodium preference, we identified a population of anterior enteric neurons, which we named internal sodium-sensing (INSO) neurons, that are essential for directing a behavioural preference for sodium. Enteric INSO neurons innervate the gut epithelia mainly through their dendritic processes and send their axonal projections along the oesophagus to the brain and to the crop duct. Through calcium imaging and CaLexA experiments, we found that INSO neurons respond immediately and specifically to sodium ions. Notably, the sodium-evoked responses were observed only after a period of sodium deprivation. Taken together, we have identified a taste-independent sodium sensor that is essential for the maintenance of sodium homeostasis.

Developing a mobile epilepsy management application integrated with an electronic health record for effective seizure management.

INTRODUCTION: Epilepsy is a chronic neurological disorder characterized by recurrent spontaneous seizures. Over 70% epilepsy patients can live normally if their seizures can be controlled. For this, many factors should be tracked and managed, but doing so is hard because of individual differences. There are mobile applications to help track these factors; however, no application covers crucial factors comprehensively, and they are complicated to use. Therefore, this study aimed to develop a mobile epilepsy management application covering crucial factors comprehensively in a user-friendly way. We evaluated the pilot version with a usability and satisfaction survey and an interview. METHODS: We established a task force comprising professionals from various fields who participated in all processes of this research. Existing service analysis and professional interviews were conducted to draw a function list. User interface and graphic user interface were designed under the supervision of the task force. After developing the application's pilot version, usability and satisfaction of the application were evaluated with eight patients and caregivers through scenario-based usability test, satisfaction survey, and interview. RESULTS: All existing mobile epilepsy management applications provide seizure and medication diary functions. We decided to provide six main functions: seizure diary, medication reminder, appointments, outpatient survey, education materials, and personal dashboard (My epilepsy). We also integrated the application with the hospital's electronic health record system. To simplify usability, frequently used and relatively important functions are located in the main page as "seizure recording" and "medication diary." Additionally, when designing graphics, art therapy was used to enhance psychological stability. For evaluation, eight participants were recruited. In scenario-based tasks, among 10 tasks, all participants completed six tasks. However, only 37.5% participants could record seizures in detail. System Usability Scale score was 84.5 points, indicating that the system was satisfactory. CONCLUSION: This study confirmed that patients' satisfaction of this application were high. Additionally, it helped them record their seizures accurately, which is very useful for seizure trend analysis, discovering seizure trigger factors, and ensuring efficient management of epilepsy. Through integration with the electronic health record, patient medical information could be utilized to guide physicians' decision-making for setting future medical treatment plan and could contribute greatly to the overall management of epilepsy.