title: Quantitative determination of haptoglobin glycoform variants in psoriasis.
abstract: Haptoglobin is an acute phase glycoprotein, secreted by hepatocytes and other types of cells including keratinocytes. Haptoglobin has been suggested to impair the immune response, inhibit gelatinases in the extracellular matrix and promote angiogenesis, but its role in psoriasis is obscure to date. Changes in haptoglobin glycan structure were observed in several diseases. The aim of this study was to investigate whether haptoglobin displays glycan variations in psoriasis. We found that the pattern of plasma haptoglobin glycoforms, following two-dimensional electrophoresis, exhibited significant quantitative differences in spot intensities between patients and controls. Quantitative and qualitative differences in glycan mass, between patients and controls, were found by mass spectrometry of glycopeptides from tryptic digests of protein isolated from both patients and controls. The number of distinct fucosylated glycoforms of peptides NLFLNHSENATAK and MVSHHNLTTGATLINEQWLLTTAK was higher in patients than in controls, but no fucosylated glycan was detected on peptide VVLHPNYSQ-VDIGLIK in either case. The number of peptides with distinct triantennary and tetraantennary glycans was higher in patients than in controls. Abundance or structure of specific glycans, which are present in haptoglobin from patients and are different or missing in normal haptoglobin, might be associated with disease activity.
authors.affiliation: Dipartimento di Patologia Sistematica - Sezione di Dermatologia, Università di Napoli Federico II, Italy.
authors.forename: Bernardetta
authors.initials: B
authors.lastname: Maresca
authors.forename: Luisa
authors.initials: L
authors.lastname: Cigliano
authors.forename: Maria M
authors.initials: MM
authors.lastname: Corsaro
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Pieretti
authors.forename: Massimo
authors.initials: M
authors.lastname: Natale
authors.forename: Enrico M
authors.initials: EM
authors.lastname: Bucci
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Dal Piaz
authors.forename: Nicola
authors.initials: N
authors.lastname: Balato
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Nino
authors.forename: Fabio
authors.initials: F
authors.lastname: Ayala
authors.forename: Paolo
authors.initials: P
authors.lastname: Abrescia
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D014644:Genetic Variation; D006020:Glycopeptides / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D006031:Glycosylation; D006242:Haptoglobins / Q000032:analysis / Q000737:chemistry* / Q000235:genetics; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D011565:Psoriasis / Q000235:genetics / Q000378:metabolism*; D014357:Trypsin / Q000737:chemistry
chemical_list: D006020:Glycopeptides; D006242:Haptoglobins; D014357:Trypsin