Identifying Small Molecule-Altered Cellular Manganese Regulatory Pathways

Science Center, Bent Corridor

Manganese (Mn) plays an essential role in many cellular processes by serving as a cofactor for various enzymatic activities. Not surprisingly, altered Mn biology can have neuropathological consequences, thus appropriate homeostatic regulation is required to avoid toxicity. Excessive Mn intake from environmental exposure can result in the development of manganism, an irreversible parkinsonian-like syndrome, and has also been reported to increase the risk of developing Parkinson’s disease. Disrupted Mn handling is also implicated in Huntington’s disease as selective deficits in brain Mn biology have been shown. Beyond several non-selective transporters, and a recently identified Mn efflux transporter, SLC30A10, the cellular signaling network for regulating neuronal Mn homeostasis is poorly understood. Previously, 41 small molecules capable of significantly altering intracellular Mn levels were identified in a high-throughput screen utilizing an immortalized murine striatal neuron lineage. These small molecules have yet to be analyzed in order to gain insight into the Mn regulatory pathways targeted. Thus, using intracellular Mn levels as the outcome measure, we explored the functional epistatic relationship of the small molecules in this neuronal lineage. We also investigated the effects of the small molecules on the SLC30A10 pathway in HeLa cells expressing wild type or mutated SLC30A10. Ultimately, we were able to delineate the most extensive intracellular Mn-altering small molecule pathway generated to date and were able to categorize the small molecules into those that may be targeting the SLC30A10 pathway. This study will provide novel insight into Mn trafficking and homeostasis and will improve understanding of Mn-dependent functions.