Glycation of PDGF results in decreased biological activity.
Advanced glycation end products (AGEs) are formed by the non-enzymatic glycation of proteins by reducing carbohydrates or alpha-oxo-aldehydes such as glyoxal and methylglyoxal and further rearrangements, eliminations and oxidations. AGE-modifications alter peptide structure, function and stability and accumulate under several pathophysiological conditions such as diabetes and are considered a biomarker of ageing. PDGF is a major regulator of wound healing, which is impaired in hyperglycaemia and ageing. We analyzed whether glycated PDGF has impaired activity in cell culture models and occurs in human subjects. PDGF was AGE-modified by the alpha-oxo-aldehydes glyoxal and methylglyoxal, which was shown by Western-blotting using alpha-carboxymethyllysine (CML) or alpha-arginine-pyrimidine (Arg-Pyr) antibodies. In mouse AKR-2B fibroblasts, this AGE-modified PDGF exhibited reduced signalling to AKT and ERK resulting in decreased cell proliferation. In the human osteosarcoma cell line 143B, PDGF signalling towards the AKT-kinase was decreased when using modified PDGF-AA, -AB, and -BB whereas the constitutive active ERK was not affected. Secreted proteins from collagen-activated platelets from diabetic subjects contained more CML-modified proteins compared to healthy controls. PDGF protein as a platelet protein coprecipitated in immunoprecipitation experiments with alpha-CML-antiserum. In summary, our data suggest that AGE-modification of PDGF contributes to reduced wound healing in diabetic patients.
Nass
Norbert
N
Martin-Luther University Halle-Wittenberg, Department of Cardiothoracic Surgery, Ernst-Grube Str. 40, D-06120 Halle/Saale, Germany. norbert.nass@medizin.uni-halle.de
Vogel
Katrin
K
Hofmann
Britt
B
Presek
Peter
P
Silber
Rolf-Edgar
RE
Simm
Andreas
A
D000818:Animals; D000077214:Becaplermin; D001792:Blood Platelets / Q000378:metabolism; D002460:Cell Line; D049109:Cell Proliferation; D003920:Diabetes Mellitus / Q000097:blood; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D017127:Glycation End Products, Advanced / Q000097:blood / Q000378:metabolism*; D006031:Glycosylation; D006037:Glyoxal / Q000737:chemistry; D006801:Humans; D006943:Hyperglycemia / Q000097:blood; D008297:Male; D051379:Mice; D008934:Mitogens / Q000502:physiology*; D010766:Phosphorylation; D010865:Pilot Projects; D015539:Platelet Activation; D010982:Platelet-Derived Growth Factor / Q000378:metabolism*; D055503:Protein Multimerization; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D020574:Proto-Oncogene Proteins c-sis; D011765:Pyruvaldehyde / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry; D015398:Signal Transduction; D014945:Wound Healing
D017127:Glycation End Products, Advanced; D008934:Mitogens; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D011994:Recombinant Proteins; C075278:platelet-derived growth factor A; C095477:platelet-derived growth factor AB; D000077214:Becaplermin; D006037:Glyoxal; D011765:Pyruvaldehyde; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases