Date of Graduation

7-2020

Document Type

Thesis

Degree Name

Master of Science in Human Environmental Science (MS)

Degree Level

Graduate

Department

General Human Environmental Sciences

Advisor

Jae Kyeom Kim

Committee Member

Betsy Garrison

Second Committee Member

Jiangchao Zhao

Third Committee Member

Sabrina Trudo

Keywords

Broccoli, Carrot, Immunity, Infant, Inflammation, miR-146a-5p

Abstract

Diets, through multiple mechanisms, cause significant impact on human health and disease etiology; proposed modes of action include modulation of non-coding RNAs and influences on the gut microbiome. Specifically, phytochemicals change human miRNA expression thereby impacting gut microbiome and/or increasing host immune functions. Apiaceous and cruciferous vegetables have been linked to decreased chronic inflammation, which is closely related with the host immune system, yet it is not investigated how these two classes of vegetables influence the colonic miRNA profile. In this study, therefore we aimed to determine the effects of short-term feeding of broccoli and carrot to infants on fecal miRNA. Three experimental groups were included: (1) control group (CON); (2) carrot group (CRT); and (3) broccoli group (BROC). Participants began the five-day study at six months of age. The puree diets (either broccoli or carrot puree) were introduced from Day 1 through Day 3 (i.e., 3 consecutive days: 2 oz per day). During the intervention period (Day 1 - Day 3), the CON group participants continued consuming breast milk and/or formula only. Diapers with stool were collected on Day 0, Day 2, and Day 4. Fecal RNA was isolated and then miRNA expression was profiled using the NanoString nCounter platform. Additionally, we subjected the miRNA results to Ingenuity Pathway Analysis (IPA) and Gene Ontology Protein Analysis Through Evolutionary Relationships (PANTHER) to predict enriched biological functions/molecular functions in broccoli- and carrot-fed infants. Compared to the CON group, 22 miRNAs and 20 miRNAs passed our criteria to be considered ‘differentially expressed’ from the CRT and BROC intervention groups, respectively. In our miRNA target prediction analyses, using IPA, a total of 132 potential mRNA target transcripts were identified in the CRT group. Similarly, in the BROC group, a total of 101 potential mRNA target transcripts was predicted. In the subsequent PANTHER analyses, ‘Positive regulation of cellular response to macrophage colony-stimulating factor stimulus’ and ‘Positive regulation of response to macrophage colony-stimulating factor’; ‘Interleukin-1, type I, activating receptor activity’; ‘Interleukin-1 receptor activity’; and ‘Interleukin-1 receptor binding’ were found to be most significantly enriched in the CRT infants. On the other hand, in the BROC group, ‘Negative regulation of natural killer cell differentiation involved in immune response’; ‘Regulation of natural killer cell differentiation’; ‘Interleukin-1, type I, activating receptor activity’; ‘Interleukin-1 receptor activity’; and ‘Interleukin-1 receptor binding’ were enriched the most. Overall, our study provides evidence that CRT and BROC intervention impacts human infants’ miRNAs and may lead to overall benefits in their immune system likely through different miRNA, predicted mRNA target transcripts, and molecular/biological functions.

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