title: Quest for Cells Responsible for Age-related Increase of Salivary Glycine and Proline.
abstract: We have previously reported that salivary glycine and proline levels are increased to nearly butanoate level in elderly people. In order to identify the source of glycine and proline, we performed high-performance liquid chromatography analysis of amino acid production to a total of seven oral cells before and after stimulation with inflammation inducers. We found that production of amino acids (per a given number of cells) by normal oral mesenchymal cells (gingival fibroblast, pulp cell, periodontal ligament fibroblast) was approximately three-fold that of oral squamous cell carcinoma cell lines (HSC-2, HSC-3, HSC-4, Ca9-22), and that production of glycine and especially proline by all these seven cells was much lower than that of glutamine and glutamic acid. Treatment of three oral mesenchymal cells with interleukin (IL)-1β or lipopoly-saccharide (LPS) reproducibly increased the production of glutamic acid and glutamine, but not that of glycine and proline. Glycine and proline only marginally stimulated the IL-8 production by IL-1β-stimulated gingival fibroblast, whereas glycine dose-dependently inhibited the nitric oxide production by lipopolysaccharide-stimulated mouse macrophage-like RAW264.7 cells. These data demonstrated that normal oral mesenchymal cells are not the major source of glycine and proline that accumulates in the saliva of aged people, suggesting the involvement of the deregulation of collagen metabolism during aging.
authors.affiliation: Department of Oral Surgery, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan Meikai University School of Dentistry, Sakado, Saitama, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Hino
authors.affiliation: Meikai University School of Dentistry, Sakado, Saitama, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Nishiyama
authors.affiliation: Meikai University School of Dentistry, Sakado, Saitama, Japan OP BIO Factory Co. Ltd., Uruma, Okinawa, Japan.
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Matsuta
authors.affiliation: Department of Oral Surgery, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Horie
authors.affiliation: Department of Oral Surgery, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Shimoyama
authors.affiliation: Meikai University School of Dentistry, Sakado, Saitama, Japan.
authors.forename: Shoji
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Meikai University School of Dentistry, Sakado, Saitama, Japan sakagami@dent.meikai.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sakagami
mesh_terms: D000367:Age Factors; D000596:Amino Acids / Q000096:biosynthesis; D000818:Animals; D002460:Cell Line; D045744:Cell Line, Tumor; D002851:Chromatography, High Pressure Liquid; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D005998:Glycine / Q000096:biosynthesis*; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D053583:Interleukin-1beta / Q000494:pharmacology; D051379:Mice; D009569:Nitric Oxide / Q000378:metabolism; D010513:Periodontal Ligament / Q000737:chemistry / Q000166:cytology; D011392:Proline / Q000096:biosynthesis*; D012463:Saliva / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D018836:Inflammation Mediators; D053583:Interleukin-1beta; D009569:Nitric Oxide; D011392:Proline; D005998:Glycine
keywords: Aging; HPLC; glycine; inflammation; normal oral cell; oral squamous carcinoma; proline; saliva