Glucose control with insulin results in reduction of NF-kappaB-binding activity in mononuclear blood cells of patients with recently manifested type 1 diabetes.
OBJECTIVE
Chronic elevated blood glucose levels are associated with the formation of advanced glycation end products (AGEs). Hyperglycaemia and AGEs have been shown to induce activation of the redox-sensitive transcription factor nuclear factor-kappaB (NF-kappaB). To validate the hypothesis that the maintenance of normal glucose levels results in the reduction of NF-kappaB-binding activity in vivo, the redox-sensitive transcription factor NF-kappaB was used as marker of hyperglycaemia-induced mononuclear cell activation in patients who recently developed type 1 diabetes.


METHODS
Twelve patients with recently manifested type 1 diabetes mellitus were examined in our study. After sampling blood for determination of baseline glucose values, the 12 patients were treated with insulin, and blood samples were taken 4 and 12 weeks later. Mononuclear cells were isolated and assayed in a tissue culture-independent electrophoretic mobility shift assay (EMSA)-based detection system for NF-kappaB-binding activity. Western blot analysis was used to determine nuclear and cytoplasmic localization of NF-kappaB-p65 and cytoplasmic content of inhibitor of kappa B-alpha (IkappaB-alpha). In addition, we determined the concentration of heme oxygenase-1 (HO-1) from cytoplasmic extract as a marker of oxidative stress.


RESULTS
Normalization of blood glucose levels resulted in a highly significant reduction of NF-kappaB activation in EMSA. Before and after glucose normalization, there were no differences in binding by the members of the NF-kappaB family to the NF-kappaB consensus sequence oligonucleotide. Similar data were obtained by Western blot analysis showing NF-kappaB-p65 localization in the nucleus, while p65 levels increased in the cytoplasm. IkappaB-alpha increased in the cytoplasm after glucose normalization. HO-1 antigen consistently decreased, as expected from the decrease in NF-kappaB activation.


CONCLUSIONS
Thus, we conclude that normalization of blood glucose levels results in the reduction of NF-kappaB activation and gene products controlled by this transcription factor.
Schiekofer
S
S
Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA 02118, USA. stephan.schiekofer@gmx.de
Galasso
G
G
Andrassy
M
M
Aprahamian
T
T
Schneider
J
J
Rocnik
E
E
D000328:Adult; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000188:drug therapy*; D024202:Electrophoretic Mobility Shift Assay / Q000379:methods; D005260:Female; D006442:Glycated Hemoglobin; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007328:Insulin / Q000627:therapeutic use*; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008297:Male; D016328:NF-kappa B / Q000097:blood*; D018384:Oxidative Stress; D051996:Transcription Factor RelA / Q000097:blood
D015415:Biomarkers; D001786:Blood Glucose; D006442:Glycated Hemoglobin; D006454:Hemoglobins; D007004:Hypoglycemic Agents; D007328:Insulin; D016328:NF-kappa B; D051996:Transcription Factor RelA; C517652:hemoglobin A1c protein, human