title: Dissecting lipid metabolism in meibomian glands of humans and mice: An integrative study reveals a network of metabolic reactions not duplicated in other tissues.
abstract: Lipids comprise the bulk of the meibomian gland secretion (meibum) which is produced by meibocytes. Complex arrays of lipogenic reactions in meibomian glands, which we collectively call meibogenesis, have not been explored on a molecular level yet. Our goals were to elucidate the possible biosynthetic pathways that underlie the generation of meibum, reveal similarities in, and differences between, lipid metabolism in meibomian glands and other organs and tissues, and integrate meibomian gland studies into the field of general metabolomics. Specifically, we have conducted detailed analyses of human and mouse specimens using genomic, immunohistochemical, and lipidomic approaches. Among equally highly expressed genes found in meibomian glands of both species were those related to fatty acid elongation, branching, desaturation, esterification, reduction of fatty acids to alcohols, and cholesterol biosynthesis. Importantly, corresponding lipid products were detected in meibum of both species using lipidomic approaches. For the first time, a cohesive, unifying biosynthetic scheme that connects genomic, lipidomic, and immunohistochemical observations is outlined and discussed.
authors.affiliation: Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; The Graduate School of Biomedical Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA. Electronic address: igor.butovich@utsouthwestern.edu.
authors.forename: Igor A
authors.initials: IA
authors.lastname: Butovich
authors.affiliation: Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
authors.forename: Anne
authors.initials: A
authors.lastname: McMahon
authors.affiliation: Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
authors.forename: Jadwiga C
authors.initials: JC
authors.lastname: Wojtowicz
authors.affiliation: Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Lin
authors.affiliation: Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
authors.forename: Ronald
authors.initials: R
authors.lastname: Mancini
authors.affiliation: Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
authors.forename: Kamel
authors.initials: K
authors.lastname: Itani
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D005227:Fatty Acids / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry; D020869:Gene Expression Profiling / Q000379:methods; D006801:Humans; D007150:Immunohistochemistry; D050356:Lipid Metabolism / Q000235:genetics / Q000502:physiology*; D008055:Lipids / Q000032:analysis; D050155:Lipogenesis / Q000235:genetics / Q000502:physiology*; D013058:Mass Spectrometry; D008537:Meibomian Glands / Q000378:metabolism*; D055442:Metabolome / Q000235:genetics / Q000502:physiology*; D055432:Metabolomics / Q000379:methods*; D051379:Mice
chemical_list: D005227:Fatty Acids; D008055:Lipids
keywords: Branched lipids; Extremely long chain lipids; Gene expression; Lipidomics; Meibocytes; Meibogenesis