title: Diabetes is associated with posttranslational modifications in plasminogen resulting in reduced plasmin generation and enzyme-specific activity.
abstract: Diabetes is associated with hypofibrinolysis by mechanisms that are only partially understood. We investigated the effects of in vivo plasminogen glycation on fibrinolysis, plasmin generation, protein proteolytic activity, and plasminogen-fibrin interactions. Plasma was collected from healthy controls and individuals with type 1 diabetes before and after improving glycemia. Plasma-purified plasmin(ogen) functional activity was evaluated by chromogenic, turbidimetric, and plasmin conversion assays, with surface plasmon resonance employed for fibrin-plasminogen interactions. Plasminogen posttranslational modifications were quantified by mass spectrometry and glycation sites located by peptide mapping. Diabetes was associated with impaired plasma fibrin network lysis, which partly normalized upon improving glycaemia. Purified plasmin(ogen) from diabetic subjects had impaired fibrinolytic activity compared with controls (723 ± 16 and 317 ± 4 s, respectively; P < .01), mainly related to decreased fibrin-dependent plasmin generation and reduced protease activity (Kcat/KM 2.57 ± 1.02 × 10⁻³ and 5.67 ± 0.98 × 10⁻³ M⁻¹s⁻¹, respectively; P < .05). Nε-fructosyl-lysine residue on plasminogen was increased in diabetes compared with controls (6.26 ± 3.43 and 1.82 ± 0.95%mol, respectively; P < .01) with preferential glycation of lysines 107 and 557, sites involved in fibrin binding and plasmin(ogen) cleavage, respectively. Glycation of plasminogen in diabetes directly affects fibrinolysis by decreasing plasmin generation and reducing protein-specific activity, changes that are reversible with modest improvement in glycemic control.
authors.affiliation: Division of Cardiovascular and Diabetes Research, Leeds Institute for Genetics, Health and Therapeutics, Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom.
authors.forename: Ramzi A
authors.initials: RA
authors.lastname: Ajjan
authors.forename: Toby
authors.initials: T
authors.lastname: Gamlen
authors.forename: Kristina F
authors.initials: KF
authors.lastname: Standeven
authors.forename: Salihah
authors.initials: S
authors.lastname: Mughal
authors.forename: Katharina
authors.initials: K
authors.lastname: Hess
authors.forename: Kerrie A
authors.initials: KA
authors.lastname: Smith
authors.forename: Emma J
authors.initials: EJ
authors.lastname: Dunn
authors.forename: M Maqsud
authors.initials: MM
authors.lastname: Anwar
authors.forename: Naila
authors.initials: N
authors.lastname: Rabbani
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Thornalley
authors.forename: Helen
authors.initials: H
authors.lastname: Philippou
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Grant
mesh_terms: D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D004789:Enzyme Activation / Q000502:physiology; D005340:Fibrinogen / Q000378:metabolism; D005341:Fibrinolysin / Q000096:biosynthesis*; D005342:Fibrinolysis / Q000502:physiology*; D006031:Glycosylation; D006801:Humans; D009088:Mucoproteins / Q000378:metabolism; D010958:Plasminogen / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D011499:Protein Processing, Post-Translational / Q000502:physiology*; D013927:Thrombosis / Q000097:blood
chemical_list: D009088:Mucoproteins; C010393:lysin, gastropoda; D005340:Fibrinogen; D010958:Plasminogen; D005341:Fibrinolysin