Hyperglycaemia promotes cerebral barrier dysfunction through activation of protein kinase C-β

B Shao, U Bayraktutan
Diabetes, Obesity & Metabolism 2013, 15 (11): 993-9

AIM: To examine whether protein kinase C (PKC) and associated downstream mechanisms are involved in hyperglycaemia (HG)-evoked blood-brain barrier (BBB) damage.

METHODS: The activities of total PKC (Peptag assay), NADPH oxidase (lucigenin assay) and matrix metalloproteinase-2 (MMP-2; gelatin zymography) were measured in human brain microvascular endothelial cells (HBMEC) exposed to normoglycaemia (5.5 mM) or HG (25 mM) using the specific assays indicated in parentheses. The integrity and function of the in vitro models of human BBB were assessed by measurements of transendothelial electrical resistance and paracellular flux of permeability markers, respectively. Occludin protein expression was studied by immunoblotting.

RESULTS: HG significantly compromised the BBB integrity and enhanced total PKC activity to which increases in PKC-β and PKC-βII isoforms contributed the most. Elevations in NADPH oxidase and MMP-2 activities and decreases in occludin levels contributed to barrier dysfunction. Selective inhibition of PKC-β isoform prevented the changes observed in occludin expression and the aforementioned enzyme activities and thus effectively preserved barrier integrity. Similarly, apocynin, a specific NADPH oxidase inhibitor, also effectively neutralized the effects of HG on barrier integrity, MMP-2 activity, occludin expression and PKC-β activity.

CONCLUSION: HG promotes cerebral-barrier dysfunction through activation of PKC-β and consequent stimulations of oxidative stress and tight junction dissolution.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"