Oxidative Stress and Diabetes

Jian Li

Beijing Institute of Geriatrics

Ministry of Health

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

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 generatio

n 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 O2

- production

Redox-dependent signaling pathways by Ang II in vascular smooth muscle cell

s

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 dihydroethidi

um staining in mesangial cells overexpressing PKC-β2

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

Possible antioxidative agents for diabetic vascular complications

Thank you!