Glycosylated human oxyhaemoglobin activates nuclear factor-kappaB and activator protein-1 in cultured human aortic smooth muscle.
Diabetic vessels undergo structural changes that are linked to a high incidence of cardiovascular diseases. Reactive oxygen species (ROS) mediate cell signalling in the vasculature, where they can promote cell growth and activate redox-regulated transcription factors, like activator protein-1 (AP-1) or nuclear factor-kappaB (NF-kappaB), which are involved in remodelling and inflammation processes. Amadori adducts, formed through nonenzymatic glycosylation, can contribute to ROS formation in diabetes. In this study, we analysed whether Amadori-modified human oxyhaemoglobin, glycosylated at either normal (N-Hb) or elevated (E-Hb) levels, can induce cell growth and activate AP-1 and NF-kappaB in cultured human aortic smooth muscle cells (HASMC). E-Hb (1 nm-1 x microm), but not N-Hb, promoted a concentration-dependent increase in cell size from nanomolar concentrations, although it failed to stimulate HASMC proliferation. At 10 nm, E-Hb stimulated both AP-1 and NF-kappaB activity, as assessed by transient transfection, electromobility shift assays or immunofluorescence staining. The effects of E-Hb resembled those of the proinflammatory cytokine tumour necrosis factor-alpha (TNF-alpha). E-Hb enhanced intracellular superoxide anions content and its effects on HASMC were abolished by different ROS scavengers. In conclusion, E-Hb stimulates growth and activates AP-1 and NF-kappaB in human vascular smooth muscle by redox-sensitive pathways, thus suggesting a possible direct role for Amadori adducts in diabetic vasculopathy.
D001011:Aorta / Q000166:cytology / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D024202:Electrophoretic Mobility Shift Assay / Q000379:methods; D005455:Fluorescent Antibody Technique / Q000379:methods; D015870:Gene Expression / Q000187:drug effects; D006031:Glycosylation; D006801:Humans; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects; D010108:Oxyhemoglobins / Q000737:chemistry / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000737:chemistry / Q000378:metabolism; D015398:Signal Transduction; D013482:Superoxide Dismutase / Q000737:chemistry / Q000378:metabolism; D013890:Thiourea / Q000031:analogs & derivatives* / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism
D016328:NF-kappa B; D010108:Oxyhemoglobins; D017382:Reactive Oxygen Species; D018808:Transcription Factor AP-1; D014157:Transcription Factors; C038983:1,3-dimethylthiourea; D013482:Superoxide Dismutase; D013890:Thiourea