Subcategory: Biomedical Engineering
Rhodesherdeline Limage - Binghamton University
Co-Author(s): Elad Tako, Robert W. Holley Center for Agriculture and Health, Ithaca, NY; Cl?udia N. H. Marques, Binghamton University, Binghamton, NY; and Gretchen Mahler, Binghamton University, Binghamton, NY.
The incidence of gastrointestinal disorders is rising, and industrial food processing and food additive consumption is expanding on a similar trajectory1. One common food additive is metal oxide nanoparticles (NP)2. Few studies have been performed on the intestinal mucus lining to better understand the role it plays as a protective barrier, and to determine if it is affected by commensal bacteria present in the gut or ingested NP. We hypothesize that different microbiota species and/or NP can alter mucus composition and intestinal function. The goal of this study is to understand if and how the mucus layer is affected by the presence of bacteria and exposure to pristine or digested metal oxide NP. To test the hypothesis that bacteria and NP food additives might alter mucus composition, thickness, and gut function, an in vitro model of the GI tract including digestion, the absorptive (Caco-2) and mucus-producing goblet (HT29-MTX) cells, and both commensal, Gram positive (Lactobacillus rhamnosus GG) and opportunistic, Gram negative (Escherichia coli ATCC 11775) bacterial strains were used. The model was exposed to physiologically relevant doses of TiO2, SiO2, ZnO or Fe2O3 NP for up to four hours. Mucus was then stained with Alcian Blue (AB), Periodic Acid Schiff (PAS), or an Alexa Fluor 488 conjugate of Wheat germ agglutinin (WGA) to determine thickness and composition. Co-cultures of Caco-2 and HT29-MTX grown for 15 days developed a visible mucus layer. AB staining indicated that acidic mucins are spread throughout the cell monolayer to serve as a protective barrier. There were no significant differences in acidic mucosubstances following exposure to NP or bacteria. PAS results showed that neutral mucosubstances significantly increased in the presence of bacteria, and significantly decreased following exposure to pristine NP and bacteria. Neutral mucins are primarily found on the epithelial surface3, and a decrease in mucus concentration can alter the function of the mucosa as a protective barrier. These results indicate that exposure to both commensal bacteria, opportunistic bacteria, and NP has impacts on the mucus layer. Since mucus is known to serve as a protective barrier, changes in the distribution or pattern may be indicative of certain pathological conditions3. Future studies involve exposing co-cultures of Caco-2/HT29-MTX to different strains of bacteria and types of NP. This model can provide a platform for understanding changes in the mucus layer, disease pathogenesis, and therapeutic options such as the manipulation of the gut microbiota to address and diagnose chronic inflammatory gut diseases. References: 1. Lerner, A, et al. Autoimmun. Rev (2015) 14:479-489. 2. Elsaesser A, et al. Adv Drug Deliv Rev (2012) 64.2:129-37. 3. Kufe, DW. Nat Rev Cancer. (2009) 9(12):874-885.
Funder Acknowledgement(s): Research presented in this abstract is supported by the National Institutes of Health (1R01ES028788), Louis Stoke Alliance Bridge to Doctorate Fellowship, Gates Millennium Scholarship.
Faculty Advisor: Gretchen Mahler, PhD, firstname.lastname@example.org
Role: I have conducted all aspects of this research as part of my dissertation under the supervision of Dr. Gretchen Mahler.