Publication Date
Fall 12-10-2025
Degree Level
B.S.
Program
Biology
First Advisor
Veronica Contreras-Shannon
Document Type
Thesis
Abstract
Abstract
Diabetes mellitus is a metabolic disorder characterized by elevated blood glucose levels due to impaired insulin secretion or diminished cellular response to insulin (resistance). Pancreatic β-cells depend on a well-organized cytoskeleton, particularly microtubules composed of α- and β-tubulin heterodimers, to transport insulin granules to the plasma membrane during glucose-stimulated insulin secretion (GSIS). Disruption of microtubule organization can impair granule trafficking and reduce insulin release. However, emerging environmental toxicants such as microplastics that interfere with β-cell cytoskeletal function remains largely unexplored.
Microplastics (MPs) are small plastic particles (< 5 mm) that have become widespread environmental contaminants and can enter biological systems. Previous studies have shown that MPs can induce cellular stress and protein misfolding, but their effects on microtubules in pancreatic β-cells are not well characterized. This study investigates whether exposure to fluorescent polystyrene microplastics alters microtubule organization and insulin secretion in βTC-6 cells.
βTC-6 cells were treated with 10 µg/mL of fluorescent polystyrene microplastics for 24 hours, followed by glucose stimulation (0, 2.5 mM or 20 mM glucose) for 3 hours. Microtubules were quantified using Tubulin Tracker Far red in the Incucyte Live-Cell Imaging System, and insulin secretion was measured by ELISA. MP internalization was assessed and confirmed through flow cytometry at the MP absorbance. Cell size increased in cells exposed to MPs by 10-15% (0 mM: p = 0.0002; 2.5 mM: p = 0.0016; 20 mM: p = 0.0002; ordinary one-way ANOVA with Tukey’s post-test) compared to their no-MP counterparts across all glucose conditions. Total tubulin fluorescence showed minor differences across glucose and MP conditions, indicating that MP exposure did not heavily affect total tubulin. Because this assay measured total fluorescence, no conclusions can be made about specific microtubule organization changes. However, insulin secretion increased with glucose stimulation, and MP treated cells showed a decrease in secretion at high glucose. These findings indicate that microplastics are readily internalized by β-cells and alter cell morphology, with potential implications for microtubule organization and insulin release. Further studies are needed to determine whether microplastics disrupt microtubule dynamics in ways that impair granule trafficking during GSIS.
Recommended Citation
garcia, anakaren, "Microplastic Exposure Alters Tubulin Leading to Alterations in Insulin Secretion by Pancreatic Beta Cells" (2025). Honors Program Theses and Research Projects. 91.
https://commons.stmarytx.edu/honorstheses/91
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