Rita Businaro

S100B protects LAN‐5 neuroblastoma cells against Aβ amyloid‐induced neurotoxicity via RAGE engagement at low doses but increases Aβ amyloid neurotoxicity at high doses

At the concentrations normally found in the brain extracellular space the glial‐derived protein, S100B, protects neurons against neurotoxic agents by interacting with the receptor for advanced glycation end products (RAGE). It is known that at relatively high concentrations S100B is neurotoxic causing neuronal death via excessive stimulation of RAGE. S100B is detected within senile plaques in Alzheimers disease, where its role is unknown. The present study was undertaken to evaluate a putative neuroprotective role of S100B against Aβ amyloid‐induced neurotoxicity. We treated LAN‐5 neuroblastoma cultures with toxic amounts of Aβ25‐35 amyloid peptide. Our results show that at nanomolar concentrations S100B protects cells against Aβ‐mediated cytotoxicity, as assessed by 3‐(4,5‐dimethyl‐thiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) and terminal deoxynucleotidyl transferase‐mediated dUTP‐fluorescein isothiocyanate nick end‐labeling (TUNEL) experiments, by countering the Aβ‐mediated decrease in the expression of the anti‐apoptotic factor Bcl‐2. This effect depends on S100B binding to RAGE because S100B is unable to contrast Aβ‐mediated neurotoxicity in neurons overexpressing a signaling‐deficient RAGE mutant lacking the cytosolic and transducing domain. Our data suggest that at nanomolar doses S100B counteracts Aβ peptide neurotoxicity in a RAGE‐mediated manner. However, at micromolar doses S100B is toxic to LAN‐5 cells and its toxicity adds to that of the Aβ peptide, suggesting that additional molecular mechanisms may be involved in the neurotoxic process.

Altered Cytokine and BDNF Levels in Autism Spectrum Disorder

The contribution of neuroimmune functioning and brain-derived neurotrophic factor (BDNF) to functional dysregulation in autism spectrum disorder was assessed in 29 patients under treatment in two specialized centers of Basilicata (Chiaromonte and Matera), Southern Italy, through analysis of serum levels of cytokines and BDNF. Elevated levels of the pro-inflammatory cytokine, including interleukin-1, interleukin-6, interleukin-12, interleukin-23, tumor necrosis factor-α and BDNF were observed, regardless of age and gender. Comparisons were made with age- and gender-related healthy controls. The present findings reinforce current notions regarding immunoexcitotoxic mechanisms contributing to the pathophysiology of autistic disorder.

Stress-induced cytokines and neuronal dysfunction in Alzheimer's disease

Increasing evidence has been accumulating about the role of stress as an important challenge to the onset and progression of Alzheimers disease (AD). The hippocampus, one of the areas of the brain damaged during AD, was the first brain region, besides the hypothalamus, to be recognized as a target of stress hormones, including cortisol, sympathetic and parasympathetic transmitters, cytokines, and metabolic hormones. The present review aims at summarizing neuroinflammatory mechanisms induced by stress, resulting in neuronal dysfunction and impaired neurogenesis. Lifestyle and environmental factors related to metabolic and inflammatory alterations observed in stressed subjects and thought to favor AD development and progression, as well as the possible ways of prevention, are discussed.

Cellular and molecular players in the atherosclerotic plaque progression.

Atherosclerosis initiation and progression is controlled by inflammatory molecular and cellular mediators. Cells of innate immunity, stimulated by various endogenous molecules that have undergone a transformation following an oxidative stress or nonenzymatic glycation processes, activate cells of the adaptive immunity, found at the borders of atheromas. In this way, an immune response against endogenous modified antigens takes place and gives rise to chronic low‐level inflammation leading to the slow development of complex atherosclerotic plaques. These lesions will occasionally ulcerate, thus ending with fatal clinical events. Plaque macrophages represent the majority of leukocytes in the atherosclerotic lesions, and their secretory activity, including proinflammatory cytokines and matrix‐degrading proteases, may be related to the fragilization of the fibrous cap and then to the rupture of the plaque. A considerable amount of work is currently focused on the identification of locally released proinflammatory factors that influence the evolution of the plaque to an unstable phenotype. A better understanding of these molecular processes may contribute to new treatment strategies. Mediators released by the immune system and associated with the development of carotid atherosclerosis are discussed.

Alzheimer's Disease Promotion by Obesity: Induced Mechanisms—Molecular Links and Perspectives

The incidence of AD is increasing in parallel with the increase in life expectancy. At the same time the prevalence of metabolic syndrome and obesity is reaching epidemic proportions in western populations. Stress is one of the major inducers of visceral fat and obesity development, underlying accelerated aging processes. Adipose tissue is at present considered as an active endocrine organ, producing important mediators involved in metabolism regulation as well as in inflammatory mechanisms. Insulin and leptin resistance has been related to the dysregulation of energy balance and to the induction of a chronic inflammatory status which have been recognized as important cofactors in cognitive impairment and AD initiation and progression. The aim of this paper is to disclose the correlation between the onset and progression of AD and the stress-induced changes in lifestyle, leading to overnutrition and reduced physical activity, ending with metabolic syndrome and obesity. The involved molecular mechanisms will be briefly discussed, and advisable guide lines for the prevention of AD through lifestyle modifications will be proposed.

Resveratrol Counteracts Inflammation in Human M1 and M2 Macrophages upon Challenge with 7-Oxo-Cholesterol: Potential Therapeutic Implications in Atherosclerosis

Macrophages consist of two main subsets: the proinflammatory M1 subset and the anti-inflammatory M2 one. 7-oxo-cholesterol, the most abundant cholesterol autoxidation product within atherosclerotic plaque, is able to skew the M1/M2 balance towards a proinflammatory profile. In the present study, we explored the ability of the polyphenolic compound resveratrol to counteract the 7-oxo-cholesterol-triggered proinflammatory signaling in macrophages. Resveratrol-pretreated human monocyte-derived M1 and M2 macrophages were challenged with 7-oxo-cholesterol and analyzed for phenotype and endocytic ability by flow cytometry, for metalloproteinase- (MMP-) 2 and MMP-9 by gelatin zymography, and for cytokine, chemokine, and growth factor secretome by a multiplex immunoassay. We also investigated the NF-κB signaling pathway. In the M1 subset, resveratrol prevented the downregulation of CD16 and the upregulation of MMP-2 in response to 7-oxo-cholesterol, whereas in M2 macrophages it prevented the upregulation of CD14, MMP-2, and MMP-9 and the downregulation of endocytosis. Resveratrol prevented the upregulation of several proinflammatory and proangiogenic molecules in both subsets. We identified modulation of NF-κB as a potential mechanism implicated in 7-oxo-cholesterol and resveratrol effects. Our results strengthen previous findings on the immunomodulatory ability of resveratrol and highlight its role as potential therapeutic or preventive compound, to counteract the proatherogenic oxysterol signaling within atherosclerotic plaque.

Fetal aorta wall inflammation in ultrasound-detected aortic intima/media thickness and growth retardation

Several studies have reported that fetuses with intrauterine growth restriction (IUGR) and infants with low birth weight present increased intima/media thickness (aIMT) of the abdominal aorta wall compared with fetuses and infants appropriate for gestational age (AGA). Evidence suggested that aIMT might be related to inflammation, probably indicating a very early stage of future adulthood disease, such as atherosclerosis. We aimed to investigate histological findings in the abdominal aorta wall of one IUGR stillbirth in which ultrasound had detected aIMT. Microscopy observations of the abdominal aorta wall confirmed the intima thickening and detected condensation of the elastic fibers forming an evident internal elastic membrane and presence of inflammatory elements, such as macrophages, activated endothelial cells, and fibroblastoid cells. The present study highlights that IUGR associated with aIMT is related to inflammation, which might represent a very early sign of future adult lesions.

Stress and Obesity as Risk Factors in Cardiovascular Diseases: A Neuroimmune Perspective

Obesity is now growing at an alarming rate reaching epidemic proportions worldwide thus increasing morbidity and mortality rates for chronic disease. But although we have ample information on the complications associated with obesity, precisely what causes obesity remains poorly understood. Some evidence attributes a major role to a low-grade chronic inflammatory state (neurogenic inflammation) induced in obesity by inflammatory mediators produced and secreted within the expanded activated adipocyte pool. Adipose tissue is an endocrine organ that secretes numerous adipose tissue-specific or enriched hormones, known as adipokines, cytokine-like molecules thought to play a pathogenic role in cardiovascular diseases. The imbalance between increased inflammatory stimuli and decreased anti-inflammatory mechanisms may depend on chronic stress. Hence the positive correlation found between stress, obesity and cardiovascular diseases. The chronic inflammatory state associated with insulin resistance and endothelial dysfunction is highly deleterious for vascular function. This review focuses on the proposed neuroimmunodulatory mechanisms linking chronic (psychological) stress, obesity and cardiovascular diseases.

7-Oxo-cholesterol potentiates pro-inflammatory signaling in human M1 and M2 macrophages

Macrophages, the major cellular components of atherosclerotic plaques, consist of two main subsets: the pro-inflammatory, M1 or classically activated macrophages, and the anti-inflammatory, M2 or alternatively activated macrophages. The molecular and cellular mechanisms that orchestrate the macrophage polarization and activation that may play a role in plaque progression and stability are poorly understood. Recent studies suggest that oxysterols, oxidative stress-mediated cholesterol oxidation products that are abundant in atherosclerotic lesions, may affect macrophage biology. We investigated whether 7-oxo-cholesterol (7oxo-C) affected polarized human M1 and M2 macrophage phenotypes and functions. Monocyte-derived M1 and M2 macrophages were challenged with 7oxo-C and their phenotype analyzed using flow cytometric analysis, and their function via secretome profiling, the presence of endocytosis and matrix metalloproteinase-9 (MMP-9) release. 7oxo-C increased the expression of HLA-DR in M1 macrophages, and CD14 on M2 macrophages. The oxysterol also reduced CD16 expression on M1 macrophages, while reducing their endocytotic capability and increasing MMP-9 secretion in M2 macrophages. Secretome profiling from cultured cell supernatants showed that 7oxo-C stimulated the production of key pro-atherogenic mediators involved in pro-inflammatory, pro-invasive and pro-angiogenic mechanisms both in M1 and M2 cells. Hypoxic conditions potentiated the effects of 7oxo-C on M1 and M2 cells. The ability of 7oxo-C to polarize macrophages toward a pro-inflammatory state represents a potentially novel mechanism by which oxidative stress can contribute to atherosclerotic lesion progression.

Interferon gamma up-regulates α2 macroglobulin expression in human astrocytoma cells

An established human astrocytoma cell line (T67) was shown to constitutively produce the proteinase inhibitor alpha 2 macroglobulin (alpha 2M). Interferon gamma (IFN gamma), a potent immunoregulatory lymphokine, was able to increase the synthesis of alpha 2M by these cells, as measured by ELISA on cell supernatants. The alpha 2M induction was also observed in other human glioma cell lines (T70 and ADF) and in human fetal astrocyte cultures following IFN gamma treatment. In T67 cells this effect was dose-dependent and the maximum (2.7-fold increase) was obtained with 2000 U/ml of IFN gamma. A corresponding enhanced alpha 2M mRNA accumulation was demonstrated by PCR and Northern blot techniques. Our results suggest an important role of alpha 2M during inflammatory and immune processes in the CNS. An increased release of alpha 2M following IFN gamma stimulation may allow the removal of the bulk of proteases released at the site of inflammation, strengthening at the same time the antigen presentation processes.