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Oxidative Stress and Diabetes
Jian
Li
Beijing Institute of Geriatrics
Ministry of Health
Redox "rheostat“ in vascular cells
Reactive oxygen species
(= ROS)
NADPH
oxidase
O2
O2
Superoxide
anion
acidic pH,
Superoxyde
Dismutase
(SOD)
H2 O2
Hydrogen
peroxide
Proposed functions of ROS
• killing of
microorganisms
• regulation of cell growth and
differentiation
• DNA damage
• regulation of cell function
• cancerogenesis
• oxygen sensing
• ageing
• activation of redox-sensitive
transcription factors
• cell death
• NO inactivation and
peroxynitrite generation
• 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 oxidases
as superoxide-producing enzymes
O2-
O2
outside
H
H115 H
H
I
II
III
Fe
IV
H
Fe
H
V
e
VI
H
inside
FAD
NH2
NADPH
COOH
The NOX family of NADPH oxidases
O
O2
EF-hands
2
gp91phox
homology
eNADPH
Nox1 colon
Nox2 phagocytes
Nox3 inner ear
Nox4 kidney
Nox5 testis and lymphoid tissues
Review: Lambeth et al. Novel homologs of gp91phox.Trends in Biochemical Sciences 25: 459-461, 2000.
Structure of the NAD(P)H oxidase
Characteristics of neutrophil and vascular NAD(P)H
oxidase
NAD(P)H Oxidase Activation
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
Mechanism for increased ROS production
induced by diabetes and insulin-resistant state
Linking various risk factors to ROS
generation in the development of IDDM
Initiation and amplification of the immune/inflammatory
response by ROS-induced NFκ B activation in β-cell death
Schematic illustration of ROS-mediated NFκB activation
Elevated glucose and FFA levels contribute to
the pathophysiology of diabetes via the
generation of ROS
The role of serine kinase activation in
oxidative stress induced insulin resistance
Vascular effects of reactive oxygen species (ROS
Modulation of cellular function by
ROS in cardiovascular diseases
Potential role of NADPH oxidase in the
pathogenesis of diabetic nephropathy
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)
PKC-β inhibition suppresses diabetes-induced O2production
Redox-dependent signaling pathways
by Ang II in vascular smooth muscle cells
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
Detection of O2- production by
dihydroethidium staining in mesangial cells
overexpressing PKC-β2
Superoxide production in nonatherosclerotic
and atherosclerotic arteries
Expression of NAD(P)H oxidase subunits in
nonatherosclerotic and atherosclerotic arteries
nonatherosclerotic arteries
atherosclerotic arteries
In situ detection of superoxide in shamoperated and injured carotid arteries
Possible antioxidative agents for diabetic vascular
complications
Thank you!