STAT5 Activation Induced by Diabetic LDL Depends on LDL Glycation and Occurs Via src Kinase Activity

Brizzi, Maria Felice; Dentelli, Patrizia; Gambino, Roberto; Cabodi, Sara; Cassader, Maurizio; Castelli, Ada; Defilippi, Paola; Pegoraro, Luigi; Pagano, Gianfranco

doi:10.2337/diabetes.51.11.3311

Cited by 24 publications

(22 citation statements)

References 38 publications

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“…LDL glycation Non-enzymatic glycation of LDL was induced by incubating native LDL with 0.3 mmol/l EDTA at 37°C for 6 weeks in the dark, in the presence of 25 mmol/l glucose, according to the method of Brizzi et al [22]. We used argon gas to prevent the oxidation of glycated and control LDL during the preparation, and removed unbound sugars by repeated and extensive dialysis.…”

Section: Methodsmentioning

confidence: 99%

Effects of different LDL particles on inflammatory molecules in human mesangial cells

et al. 2008

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Aims/hypothesis Inflammation is a mechanism of glomerular damage in chronic glomerulopathies. LDL may increase the production of inflammatory cytokines in renal tissues. However, the relative role of native, oxidised and glycated LDL in promoting this process has been only partially elucidated. Methods We tested the inflammatory and proapoptotic effects of native, oxidised and glycated LDL in human mesangial cells (HMCs) by measuring levels of IL6, CD40 and macrophage migration inhibitory factor (MIF) genes, MIF protein, release of IL6, soluble CD40, fibronectin and laminin, early and late apoptosis, and extracellular regulated kinases (ERK) 1/2 and c-Jun N-terminal kinase (JNK) activation. Results IL6 and CD40 mRNA were dose-dependently upregulated by all three species; this was closely paralleled by their increased release. MIF mRNA was potently stimulated by modified LDL, as confirmed by immunostaining. Fibronectin and laminin release was stimulated by both oxidised and glycated, but not native, LDL. All LDL species induced some increase in late, but not early, apoptosis, and similarly activated JNK2/3 phosphorylation; in contrast, ERK1/2 phosphorylation was more strongly upregulated by oxidised than either native or glycated LDL.Conclusions In HMCs, the production and release of IL6 and CD40 is stimulated by both native and modified LDL, while MIF is more strongly stimulated by oxidised LDL. Regarding the pattern of mesangial expansion, fibronectin and laminin are upregulated by oxidised and glycated LDL. Apoptosis, if modest, is induced by all species. Intracellular signalling of native and modified LDL involves JNK2/3 and, perhaps more specifically, ERK1/2. Tight control of the lipid profile may be useful in preserving kidney function in patients with metabolic alterations.

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Section: Methodsmentioning

confidence: 99%

Effects of different LDL particles on inflammatory molecules in human mesangial cells

et al. 2008

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“…Cells were lysed, and protein concentration was obtained as described previously (30). In selected experiments the anti-EGFR pharmacological inhibitor, AG1478 (250 nM/liter), NAC (20 mM/liter), DPI (10 M/liter), Erk1/2 MAPK inhibitor (35 M/liter), PD98059, or blocking anti-LOX-1 antibody (1 g/ml) were used.…”

Section: Methodsmentioning

confidence: 99%

“…Proteins (50 g) were separated on SDS-PAGE transferred to nitrocellulose membranes and analyzed by Western blot. Reaction with antibodies and detection with chemiluminescence system were performed as described previously (30).…”

Section: Methodsmentioning

confidence: 99%

Oxidative Stress-mediated Mesangial Cell Proliferation Requires RAC-1/Reactive Oxygen Species Production and β4 Integrin Expression

Dentelli

Rosso

Zeoli

et al. 2007

Journal of Biological Chemistry

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Lipid abnormalities and oxidative stress, by stimulating mesangial cell (MC) proliferation, can contribute to the development of diabetes-associated renal disease. In this study we investigated the molecular events elicited by oxidized low density lipoproteins (ox-LDL) in MC. We demonstrate that in MC cultured in the presence of ox-LDL, survival and mitogenic signals on Akt and Erk1/2 MAPK pathways are induced, respectively. Moreover, as shown by the expression of the dominant negative Rac-1 construct, we first report that ox-LDL-mediated cell survival and cell cycle progression depend on Rac-1 GTPase-mediated reactive oxygen species production and on epidermal growth factor receptor transactivation. By silencing Akt and blocking Erk1/2 MAPK pathways, we also demonstrate that these signals are downstream to Rac-1/reactive oxygen species production and epidermal growth factor receptor activation. Finally, by endogenous depletion of ␤4 integrin, expressed in MC, we provide evidence that the expression of this adhesion molecule is essential for ox-LDL-mediated MC dysfunction. Our data identify a novel signaling pathway involved in oxidative stress-induced diabetes-associated renal disease and provide the rationale for therapeutically targeting ␤4 integrin.Abnormalities in lipoprotein metabolism are commonly observed in patients with renal disease. Specifically, hyperlipidemia and glomerular lipid deposition of atherogenic lipoproteins (low density lipoproteins (LDL), 2 and their oxidized variants, ox-LDL) are implicated in key pathobiological processes involved in the development of glomerular diseases, including mesangial cell (MC) hypercellularity (1). The relevance of mitogen intracellular signaling in mesangial proliferative disease has only recently been recognized (2). Indeed, accumulation of atherogenic lipoproteins within the glomerulus, by activating membrane receptor protein-tyrosine kinases (RPTK), such as the epidermal growth factor receptor (EGFR), triggers MAPK cascades leading to cyclin/cyclin-dependent kinase activation of DNA synthesis and MC proliferation (2). Moreover, in smooth muscle cells, ox-LDL (3) has been shown to trigger the phosphatidylinositol 3-kinase/Akt signaling pathway (4). These data thus suggest that atherogenic lipoproteins may act as one of the major endogenous modulators for mitogenic signaling response within the glomerulus.Although superoxide anions and hydrogen peroxide are generally considered to be toxic, recent evidence suggests that the production of the reactive oxygen species (ROS) might be an integral component of membrane receptor signaling (5). In mammalian cells, a vast array of intracellular stimuli have been shown to induce a transient increase in the intracellular ROS concentrations, and specific inhibition of ROS generation results in a complete blockage of stimulant-dependent signaling (5). In particular, growth factor-mediated ROS generation seems to be necessary for propagation of downstream mitogenic and antiapoptotic signals (5).Rho family GTPases are imp...

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“…Glycosylation is a process that increases the negative charge of LDL [4]. Modifications that increase the net negative charge may have important metabolic consequences and enhance LDL atherogenicity [5,6]. Glycated LDL (glyc-LDL) is catabolized more slowly than normal LDL [7,8], and is degraded by the scavenger pathway promoting foam cell formation [9].…”

Section: Introductionmentioning

confidence: 99%

In vivo oxidizability of LDL in type 2 diabetic patients in good and poor glycemic control

et al. 2004

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We aimed to determine if increased non-enzymatic glycosylation of the LDL was sufficient to increase the susceptibility to in vivo oxidation of the LDL particles. Twenty-two type 2 diabetic patients (11 males and 11 females) were included in this study. They were enrolled on the basis of good [glycated hemoglobin (HbA 1c ) < 7%] and poor glycemic control [(HbA 1c ) > 8%]. LDL were isolated by sequential ultracentrifugation and analyzed by capillary electrophoresis (CE) for diene conjugate content and for electronegativity. The glyc-LDL levels were increased in all diabetic type 2 patients, peaking in the diabetic subjects in poor diabetic control (17.3 ± 8.07%). The LDL content of diene conjugates was similar between the two groups (6.65 ± 0.77% for the patients with good glycemic control versus 6.88 ± 0.74% for those with poor glycemic control; P = 0.49) as was the electrophoretic mobility ((−1.14544 ± 0.089) × 10 −4 cm 2 /(V s) for the patients with good glycemic control and (−1.13666 ± 0.073) × 10 −4 cm 2 /(V s) for those with poor glycemic control; P = 0.80).The susceptibility to in vivo oxidation of LDL from type 2 diabetic patients in poor glycemic control did not differ from that of well-controlled diabetic patients. LDL glycosylation was not able to increase the oxidizability of LDL in the diabetic patients with poor glycemic control.

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STAT5 Activation Induced by Diabetic LDL Depends on LDL Glycation and Occurs Via src Kinase Activity

Cited by 24 publications

References 38 publications

Effects of different LDL particles on inflammatory molecules in human mesangial cells

Effects of different LDL particles on inflammatory molecules in human mesangial cells

Oxidative Stress-mediated Mesangial Cell Proliferation Requires RAC-1/Reactive Oxygen Species Production and β4 Integrin Expression

In vivo oxidizability of LDL in type 2 diabetic patients in good and poor glycemic control

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