Glial Mitochondrial Morphology and Its Impact on Neuronal Function: MARF Manipulation in Drosophila
Board Location: #46
Discipline: Biological Sciences
Subcategory: cell & molecular biology
Session: 2
Natalia M. Jimenez-Vizcarrondo - University of Puerto Rico - Río Piedras campus
Co-Author(s): Christian D. Del Valle, University of Puerto Rico - Río Piedras ; Nicolas Fuenzalida, University of Puerto Rico - Río Piedras; Alfredo Ghezzi, University of Puerto Rico - Río Piedras; Erin L. Barnhart, Columbia University in the city of New York
Proper neuronal function requires substantial energy, with neuroplastic processes further amplifying these demands to support communication and adaptability within the brain. This energy is primarily generated in neurons through mitochondrial oxidative phosphorylation (OXPHOS). Glial cells are believed to play a critical role in supporting neuronal metabolism, specifically by shuttling lactate, a by-product of glycolysis, to neurons. Notably, in vivo studies have demonstrated that knocking down lactate transporters in glial cells significantly reduces fly viability. Although it is commonly perceived that glial cells rely primarily on glycolysis and the role of the mitochondria is less predominant, recent findings from the Barnhart lab indicate that glial cells contain a high proportion of large, highly branched mitochondria. Despite this, the functional significance of mitochondrial morphology in glial cells remains poorly understood. This study will investigate how altering mitochondrial morphology in glial cells could profoundly affect neuronal function and neuroplasticity in Drosophila melanogaster. To investigate this, genetic manipulation using the GAL4/UAS system will be employed to regulate the expression of Marf, a mitochondrial pro-fusion factor. Specifically, Marf will be upregulated to promote mitochondrial elongation and downregulated using RNAi to induce shorter, more punctate mitochondria. It is hypothesized that overexpression of Marf, resulting in elongated mitochondria, will have minimal impact on viability, whereas Marf knockdown, leading to fragmented mitochondria, will greatly reduce fly viability. To assess the structural consequences of these manipulations, Drosophila brains will be analyzed using confocal microscopy. In addition, behavioral assays, including the geotaxis climbing assay and fly activity assays, will be performed to evaluate neuronal function. Alcohol will also be introduced as a variable to examine the effects of glial mitochondrial perturbation on neuroplasticity processes. This study aims to elucidate the role of mitochondrial morphology in glial cells and its impact on neuronal function and neuroplastic processes, providing insights into how glial cells contribute to the overall health and adaptability of the nervous system.
Funder Acknowledgement(s): NIH Grant 5P20GM103642; NIH 5R25GM061151-19; NSF Grant 1736026; NIH Grant 2R25NS080687; NIH Grant P20GM103475; NSF Grant 1633184; NSF Grant 2131647; PR-LSAMP
Faculty Advisor: Alfredo Ghezzi Grau, alfredo.ghezzi@upr.edu
Role: I conducted all aspects of this research, including designing and executing experiments to alter mitochondrial morphology in glial cells of Drosophila. I manipulated Marf expression, inducing both overexpression and RNAi suppression, using genetic tools and fly crosses. I performed activity and geotaxis assays, with and without alcohol, to assess neuronal function and neuroplasticity. Additionally, I prepared samples for confocal microscopy to analyze phenotypic changes. With assistance from Christian del Valle and Nicolas Fuenzalida, I conducted statistical analyses to evaluate the results.