Post on 26-Dec-2015
Redox "rheostat“ in vascular cells
Reactive oxygen species (= ROS)
O2 O2- H2 O2
acidic pH,Superoxyde
Dismutase (SOD)
NADPH oxidase
Superoxideanion
Hydrogenperoxide
Proposed functions of ROS
• killing of microorganisms
• DNA damage
• cancerogenesis
• ageing
• cell death
• NO inactivation and peroxynitrite generation
• regulation of cell growth and differentiation
• regulation of cell function
• oxygen sensing
• activation of redox-sensitive transcription factors
• activation of redox-sensitive second messenger systems
Where and why are reactive oxygen species generated?
• Mitochondria– by-product of the oxidative metabolism
• Phagocyte NADPH oxidase – microbial killing
• NADPH oxidase of non-phagocytic cells – cell growth, cell signaling
NOX-type NADPH oxidasesas superoxide-producing enzymes
Fe
Fe
outside
inside
I VIIVII III V
NH2
H H
HH
H
H
NADPH
FAD
COOH
H115
O2 O2-
e-
The NOX family of NADPH oxidases
Review: Lambeth et al. Novel homologs of gp91phox.Trends in Biochemical Sciences 25: 459-461, 2000.
gp91phox homology
EF-hands
Nox1 colonNox2 phagocytesNox3 inner earNox4 kidneyNox5 testis and lymphoid tissues
O2 O2-
NADPH
e-
Structure of the NAD(P)H oxidaseStructure of the NAD(P)H oxidase
Adenovirus-induced overexpression of PKC-β2 causes the membranous translocation of p47phox and p67phox
A model illustrating how increased ROS production in accumulated fat contributes to metabolic syndrome
Initiation and amplification of the immune/inflammatory response by ROS-induced NFκ B activation in β-cell death
Elevated glucose and FFA levels contribute to the pathophysiology of diabetes via the generatio
n of ROS
Effect of high glucose level and PMA on ROS production in aortic smooth muscle cells (A) and endothelial cells (B)
Effect of diphenylene iodonium on high glucose– or PMA-induced increase in ROS production in aortic smooth muscle cells (A) or endothelial cells (B)
Detection of intracellular production of reactive oxygen species.
A. Fluorescence microscopy visualization of ROS production in pericytes and smooth muscle cells. a: control;b: cells cultured in 25 mM glucose and AGE-Lys stimulated with Ang II;c and d : corresponding phase contrast microscopy. B. Pericytes cultured in the pro-diabetic environment, were loaded for 30 min at 37oC with 5mM DCF-DA .
The effect of high glucose concentration, AGE-Lys and their combination with Ang II on intracellular calcium [Ca2+]i
Superoxide production in nonatherosclerotic Superoxide production in nonatherosclerotic and atherosclerotic arteriesand atherosclerotic arteries
nonatherosclerotic arteries atherosclerotic arteries
Expression of NAD(P)H oxidase subunits in nonatExpression of NAD(P)H oxidase subunits in nonatherosclerotic and atherosclerotic arteriesherosclerotic and atherosclerotic arteries
In situ detection of superoxide in sham-oIn situ detection of superoxide in sham-operated and injured carotid arteriesperated and injured carotid arteries