Autoantibodies to the C-terminal subunit of RLIP76 induce oxidative stress and endothelial cell apoptosis in immune-mediated vascular diseases and atherosclerosis

[High cardiovascular complications in systemic lupus erythematosus: physiopathology and risk management]

Today, cardiovascular mortality is the first cause of mortality in systemic lupus erythematosus (SLE). A 40-year-old woman with SLE is over 50 times more likely to have a myocardial infraction than a healthy woman of similar age. The high CV risk has a double origin: an early and progressive atherosclerosis and a prothrombotic propensity. Multiple factors are incriminated, including a higher prevalence of traditional CV risk factors in SLE population, as well as SLE-specific factors. Autoantibodies can modify lipid profile, induce tissue factor synthesis, favour clotting and endothelial apoptosis. Moreover, endothelial dysfunction and permanent chronic inflammation are present. Treatments are occasionally involved. To reduce more efficiently CV risk in SLE patients, we propose to consider SLE has a complete CV risk factor that should be implemented for CV risk management. This medical procedure of CV risk estimation is unusual in young patients. Its implementation in SLE patients requires a modification of medical practices. CV risk management in SLE patients include identification of optimal targets for each traditional risk factor and SLE specific treatments.

Premature vascular damage in systemic lupus erythematosus: an imbalance of damage and repair?

Systemic lupus erythematosus (SLE) is associated with an increase in the risk of premature cardiovascular complications caused by accelerated atherosclerosis, which significantly contributes to morbidity and mortality. Standard Framingham risk factors seem to be less important predictors of cardiovascular events than the presence of active SLE, and the immune dysregulation characteristic of lupus seems to play a dominant role in atherogenesis. Although both SLE-specific and nonspecific mechanisms have been proposed to play a prominent role in the induction of premature vascular damage in this disease, the exact etiology remains unclear. This review summarizes some of the proposed mechanisms that may promote accelerated vascular damage in lupus and explores potential targets for cardiovascular risk prevention in this patient population.

Chromatographic and mass spectrometric analysis of glutathione in biological samples

Biological thiol compounds are classified into high-molecular-mass protein thiols and low-molecular-mass free thiols. Endogenous low-molecular-mass thiol compounds, namely, reduced glutathione (GSH) and its corresponding disulfide, glutathione disulfide (GSSG), are very important molecules that participate in a variety of physiological and pathological processes. GSH plays an essential role in protecting cells from oxidative and nitrosative stress and GSSG can be converted into the reduced form by action of glutathione reductase. Measurement of GSH and GSSG is a useful indicator of oxidative stress and disease risk. Many publications have reported successful determination of GSH and GSSG in biological samples. In this article, we review newly developed techniques, such as liquid chromatography coupled with mass spectrometry and tandem mass spectrometry, for identifying GSH bound to proteins, or for localizing GSH in bound or free forms at specific sites in organs and in cellular locations.

Clinical Immunology Review Series: an approach to the patient with recurrent orogenital ulceration, including Behçet's syndrome

Patients presenting with recurrent orogenital ulcers may have complex aphthosis, Behçet's disease, secondary complex aphthosis (e.g. Reiter's syndrome, Crohn's disease, cyclical neutropenia) or non-aphthous disease (including bullous disorders, erythema multiforme, erosive lichen planus). Behçet's syndrome is a multi-system vasculitis of unknown aetiology for which there is no diagnostic test. Diagnosis is based on agreed clinical criteria that require recurrent oral ulcers and two of the following: recurrent genital ulcers, ocular inflammation, defined skin lesions and pathergy. The condition can present with a variety of symptoms, hence a high index of suspicion is necessary. The most common presentation is with recurrent mouth ulcers, often with genital ulcers; however, it may take some years before diagnostic criteria are met. All patients with idiopathic orogenital ulcers should be kept under review, with periodic focused assessment to detect evolution into Behçet's disease. There is often a delay of several years between patients fulfilling diagnostic criteria and a diagnosis being made, which may contribute to the morbidity of this condition. Despite considerable research effort, the aetiology and pathogenesis of this condition remains enigmatic.

Are autoantibodies triggering endothelial cell apoptosis really pathogenic?

Anti-endothelial cell (EC) antibodies (AECA) are a heterogeneous group of antibodies directed against a variety of EC membrane proteins. A pathogenic role for AECA in diseases that involve the vascular system has not been clearly demonstrated. Induction of EC apoptosis appears to be one of the mechanisms by which AECA may exert their effect. AECA from some patients trigger the translocation of anionic phospholipids, most notably phosphatidylserine, from the inner to the outer leaflet of the plasma membrane, and thereafter activation of caspase 3 and cleavage of poly (ADP-ribose) polymerase, hallmarks of apoptosis. Apoptotic cell death generates oxidatively modified moieties, which can induce autoimmune and local inflammatory responses. While a sole AECA target involved in the apoptotic process of ECs has not been identified, some evidence suggests that Heat Shock Proteins may be an outstanding antigen.

RLIP76: A novel glutathione-conjugate and multi-drug transporter

RLIP76, a stress-responsive, multi-functional protein with multi-specific transport activity towards glutathione-conjugates (GS-E) and chemotherapeutic agents, is frequently over-expressed in malignant cells. Our recent studies suggest that it plays a prominent anti-apoptotic role selectively in cancer cells. We have previously shown that RLIP76 accounts for up to 80% of the transport of GS-E and blocking the RLIP76-mediated transport of GS-E in cells results in the accumulation of pro-apoptotic endogenous electrophiles and on-set of apoptosis. Here we demonstrate that when RLIP76 mediate transport of GS-E is abrogated either by anti-RLIP76 IgG or accumulation of 4-hydroxynonenal (4-HNE) and its GSH-conjugate (GS-HNE) occurs and a massive apoptosis is observed in cells, indicate that the inhibition of RLIP76 transport activity at the cell surface is sufficient for observed anti-tumor activity. RLIP76 is linked with certain cellular functions including membrane plasticity and movement (as a primary 'effector' in the Ral pathway, perhaps functioning as a GTPase activating protein, or GAP), and as a component of clathrin-coated pit-mediated receptor-ligand endocytosis-a process that mediates movement of membrane vesicles.