Keywords

probiotics, Barrett's Esophagus, mucin, GERD, cancer, microbiome

Abstract

Gastroesophageal Reflux Disease (GERD) can progress to the precancerous Barrett’s Esophagus (BE) condition, in which the normal esophageal squamous epithelium is replaced with a columnar epithelium containing goblet cells. Mucins, sticky substances, are secreted in response to bile acid exposure during reflux episodes to protect the esophageal epithelium. Goblet cells secrete these mucins, which can also scaffold microbial colonization. Probiotic Lactobacillus bacteria can use glycosidase enzymes to process mucin and metabolize them into their component sugars (glycans). This project aims to identify the role of the Lactobacillus-mucin interaction in BE, as glycan availability could confer an advantage to Lactobacillus itself, precancerous cells, or other commensal microbiota. We hypothesized that Lactobacillus spp. growth is enhanced in the presence of mucin. We assessed growth of Lactobacillus acidophilus, L.plantarum, and L. fermentum cultured with 0.05% and 0.1% mucin using colony forming unit (CFU) calculations and growth curves. To identify surface colonization, we performed biofilm assays that protect bacteria from environmental stressors. We observed that Lactobacillus spp.had enhanced growth and attachment in the presence of mucin. We also assessed Lactobacillus growth in mucin’s component glycans (galactose, fucose, Neu5Ac, GalNAc, GluNAc) to identify specific nutrients promoting Lactobacillus colonization, showing that the three species favored galactose, GalNAc, and GluNAc as growth media. Furthermore, we conducted CellTiter-Blue Cell Viability assays on CP-B and BAR-T BE cell lines (high-grade, and low-grade dysplasia, respectively) to investigate the effect of the Lactobacillus-mucin and Lactobacillus-glycan interactions on precancerous cell growth. Identifying how mucin and its glycans contribute to host-microbe symbiosis could ultimately be used as innovative nutritional strategies aimed at improving mucosal health by restoring the commensal microbiome.

Thesis Completion Year

2026

Thesis Completion Semester

Spring

Thesis Chair

Andl, Claudia

College

College of Medicine

Department

Burnett School of Biomedical Sciences

Thesis Discipline

Biomedical Sciences

Language

English

Access Status

Open Access

Length of Campus Access

None

Campus Location

Orlando (Main) Campus

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