High glucose, glucose fluctuation and carbonyl stress enhance brain microvascular endothelial barrier dysfunction: Implications for diabetic cerebral microvasculature
| Autor: | Wei Li, Ronald E. Maloney, Tak Yee Aw |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Male
Glycosylation Clinical Biochemistry AGEs advanced glycation end products SDL S-D-lactoylglutathione Occludin Biochemistry N-acetylcysteine & endothelial barrier function RCS reactive carbonyl species chemistry.chemical_compound Occludin glycation & brain endothelial barrier function 0302 clinical medicine Glycation GSH glutathione Endothelial dysfunction BBB blood–brain barrier lcsh:QH301-705.5 Barrier function NAC N-acetyl-L-cysteine Hyperglycemia & methylglyoxal 0303 health sciences lcsh:R5-920 Methylglyoxal Lactoylglutathione Lyase Brain Free Radical Scavengers Pyruvaldehyde Glutathione Endothelial stem cell lcsh:Medicine (General) Research Paper medicine.medical_specialty TEER transendothelial electrical resistance BSO L-buthionine-(S R)-sulfoximine STZ streptozotocin Cell Line Diabetes Mellitus Experimental 03 medical and health sciences PCA perchloric acid RIPA radio immunoprecipitation assay buffer Diabetes mellitus Internal medicine medicine Animals Humans Rats Wistar Diabetic brain microvascular dysfunction Buthionine Sulfoximine 030304 developmental biology business.industry Organic Chemistry Endothelial Cells IHEC immortalized human brain endothelial cell line medicine.disease Acetylcysteine Rats Streptozotocin & diabetes Oxidative Stress Endocrinology Glucose chemistry lcsh:Biology (General) Microvessels HPLC high-performance liquid chromatography MG methylglyoxal Thiolester Hydrolases Carbonyl stress & endothelial GSH business 030217 neurology & neurosurgery |
| Zdroj: | Redox Biology, Vol 5, Iss, Pp 80-90 (2015) Redox Biology |
| ISSN: | 2213-2317 |
| DOI: | 10.1016/j.redox.2015.03.005 |
| Popis: | We previously demonstrated that in normal glucose (5 mM), methylglyoxal (MG, a model of carbonyl stress) induced brain microvascular endothelial cell (IHEC) dysfunction that was associated with occludin glycation and prevented by N-acetylcysteine (NAC). Herein, we investigated the impact of high glucose and low GSH, conditions that mimicked the diabetic state, on MG-induced IHEC dysfunction. MG-induced loss of transendothelial electrical resistance (TEER) was potentiated in IHECs cultured for 7 or 12 days in 25 mM glucose (hyperglycemia); moreover, barrier function remained disrupted 6 h after cell transfer to normal glucose media (acute glycemic fluctuation). Notably, basal occludin glycation was elevated under these glycemic states. TEER loss was exaggerated by inhibition of glutathione (GSH) synthesis and abrogated by NAC, which corresponded to GSH decreases and increases, respectively. Significantly, glyoxalase II activity was attenuated in hyperglycemic cells. Moreover, hyperglycemia and GSH inhibition increased MG accumulation, consistent with a compromised capacity for MG elimination. α-Oxoaldehydes (MG plus glyoxal) levels were elevated in streptozotocin-induced diabetic rat plasma. Immunohistochemistry revealed a prevalence of MG-positive, but fewer occludin-positive microvessels in the diabetic brain in vivo, and Western analysis confirmed an increase in MG–occludin adducts. These results provide the first evidence that hyperglycemia and acute glucose fluctuation promote MG–occludin formation and exacerbate brain microvascular endothelial dysfunction. Low occludin expression and high glycated-occludin contents in diabetic brain in vivo are factors that would contribute to the dysfunction of the cerebral microvasculature during diabetes. Graphical abstract Highlights • Methylglyoxal (MG) induced electrical resistance (TEER)loss in brain microvascular endothelial cells. • TEER loss was potentiated by hyperglycemia, and low glutathione. • TEER loss was correlated with occludin-glycation and was attenuated and exacerbated by NAC and BSO, respectively. • Hyperglycemia decreased glyoxalase II activity and promoted free MG accumulation. • Diabetic brain in vivo exhibiteda prevalence of MG-positive microvessels and increased occludin–MG adducts. |
| Databáze: | OpenAIRE |
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