title: Sensing Small Changes in Protein Abundance: Stimulation of Caco-2 Cells by Human Whey Proteins.
abstract: Mass spectrometry (MS)-based proteomic approaches have largely facilitated our systemic understanding of cellular processes and biological functions. Cutoffs in protein expression fold changes (FCs) are often arbitrarily determined in MS-based quantification with no demonstrable determination of small magnitude changes in protein expression. Therefore, many biological insights may remain veiled due to high FC cutoffs. Herein, we employ the intestinal epithelial cell (IEC) line Caco-2 as a model system to demonstrate the dynamicity of tandem-mass-tag (TMT) labeling over a range of 5-40% changes in protein abundance, with the variance controls of ± 5% FC for around 95% of TMT ratios when sampling 9-12 biological replicates. We further applied this procedure to examine the temporal proteome of Caco-2 cells upon exposure to human whey proteins (WP). Pathway assessments predict subtle effects due to WP in moderating xenobiotic metabolism, promoting proliferation and various other cellular functions in differentiating enterocyte-like Caco-2 cells. This demonstration of a sensitive MS approach may open up new perspectives in the system-wide exploration of elusive or transient biological effects by facilitating scrutiny of narrow windows of proteome abundance changes. Furthermore, we anticipate this study will encourage more investigations of WP on infant gastrointestinal tract development.
authors.affiliation: Mead Johnson Nutrition, 2400 West Lloyd Expressway, Evansville, Indiana 47721, United States.
authors.forename: Judy K
authors.initials: JK
authors.lastname: Cundiff
authors.affiliation: Mead Johnson Nutrition, 2400 West Lloyd Expressway, Evansville, Indiana 47721, United States.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: McConnell
authors.affiliation: Mead Johnson Nutrition, 2400 West Lloyd Expressway, Evansville, Indiana 47721, United States.
authors.forename: Kimberly J
authors.initials: KJ
authors.lastname: Lohe
authors.affiliation: Mead Johnson Nutrition, 2400 West Lloyd Expressway, Evansville, Indiana 47721, United States.
authors.forename: Sarah D
authors.initials: SD
authors.lastname: Maria
authors.affiliation: Mead Johnson Nutrition, 2400 West Lloyd Expressway, Evansville, Indiana 47721, United States.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: McMahon
authors.affiliation: Mead Johnson Nutrition, 2400 West Lloyd Expressway, Evansville, Indiana 47721, United States.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
mesh_terms: D018938:Caco-2 Cells; D056148:Chromatography, Reverse-Phase; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D006801:Humans; D020543:Proteome / Q000302:isolation & purification / Q000378:metabolism*; D040901:Proteomics / Q000379:methods; D053719:Tandem Mass Spectrometry; D000067816:Whey Proteins / Q000494:pharmacology*
chemical_list: D020543:Proteome; D000067816:Whey Proteins
keywords: Caco-2; TMT; intestinal epithelial cells; milk proteins; quantitative proteomics