Mitochondrial dysfunction: different routes to Alzheimer's disease therapy.

Mitochondria are dynamic ATP-generating organelle which contribute to many cellular functions including bioenergetics processes, intracellular calcium regulation, alteration of reduction-oxidation potential of cells, free radical scavenging, and activation of caspase mediated cell death. Mitochondrial functions can be negatively affected by amyloid ß peptide (Aß), an important component in Alzheimer's disease (AD) pathogenesis, and Aß can interact with mitochondria and cause mitochondrial dysfunction. One of the most accepted hypotheses for AD onset implicates that mitochondrial dysfunction and oxidative stress are one of the primary events in the insurgence of the pathology. Here, we examine structural and functional mitochondrial changes in presence of Aß. In particular we review data concerning Aß import into mitochondrion and its involvement in mitochondrial oxidative stress, bioenergetics, biogenesis, trafficking, mitochondrial permeability transition pore (mPTP) formation, and mitochondrial protein interaction. Moreover, the development of AD therapy targeting mitochondria is also discussed.

Cigarette smoke alters IL-33 expression and release in airway epithelial cells.

Airway epithelium is a regulator of innate immune responses to a variety of insults including cigarette smoke. Cigarette smoke alters the expression and the activation of Toll Like Receptor 4 (TLR4), an innate immunity receptor. IL-33, an alarmin, increases innate immunity Th2 responses. The aims of this study were to explore whether mini-bronchoalveolar lavage (mini-BAL) or sera from smokers have altered concentrations of IL-33 and whether cigarette smoke extracts (CSE) alter both intracellular expression (mRNA and protein) and release of IL-33 in bronchial epithelial cells. The role of TLR4 in the expression of IL-33 was also explored. Mini-BALs, but not sera, from smokers show reduced concentrations of IL-33. The expression of IL-33 was increased also in bronchial epithelium from smokers. 20% CSE reduced IL-33 release but increased the mRNA for IL-33 by real time PCR and the intracellular expression of IL-33 in bronchial epithelial cells as confirmed by flow cytometry, immunocytochemistry and western blot analysis. The effect of CSE on IL-33 expression was also observed in primary bronchial epithelial cells. IL-33 expression was mainly concentrated within the cytoplasm of the cells. LPS, an agonist of TLR4, reduced IL-33 expression, and an inhibitor of TLR4 increased the intracellular expression of IL-33. In conclusion, the release of IL-33 is tightly controlled and, in smokers, an altered activation of TLR4 may lead to an increased intracellular expression of IL-33 with a limited IL-33 release.

HLA and killer cell immunoglobulin-like receptors influence the natural course of CMV infection.

BACKGROUND: Natural killer (NK) cells provide a major defense against cytomegalovirus (CMV) infection through the interaction of their surface receptors, including the activating and inhibitory killer immunoglobulin-like receptors (KIRs), and human leukocyte antigens (HLA) class I molecules. This study assessed whether the KIR and HLA repertoire may influence the risk of developing symptomatic or asymptomatic disease after primary CMV infection in the immunocompetent host. METHODS: Sixty immunocompetent patients with primary symptomatic CMV infection were genotyped for KIR and their HLA ligands, along with 60 subjects with a previous asymptomatic infection as controls. RESULTS: The frequency of the homozygous A haplotype (only KIR2DS4 as activating KIR) was higher in symptomatic patients than controls (30% vs 12%, respectively; odds ratio [OR] = 3.24; P = .01). By logistic regression, the risk of developing symptomatic disease was associated with the homozygous A haplotype and the HLABw4(T) allele. Combining the 2 independent variables, we found that 37 out of 60 (62%) symptomatic patients but only 18 out of 60 (30%) of controls possessed the homozygous A haplotype or the HLABw4(T) allele with a highly significant OR (OR = 3.75, P < .0005). CONCLUSIONS: Immunocompetent subjects carrying the homozygous A haplotype or the HLABw4(T) allele are at higher risk of developing symptomatic disease after primary CMV infection.

Carbocysteine regulates innate immune responses and senescence processes in cigarette smoke stimulated bronchial epithelial cells.

Cigarette smoke represents the major risk factor for chronic obstructive pulmonary disease (COPD). Cigarette smoke extracts (CSE) alter TLR4 expression and activation in bronchial epithelial cells. Carbocysteine, an anti-oxidant and mucolytic agent, is effective in reducing the severity and the rate of exacerbations in COPD patients. The effects of carbocysteine on TLR4 expression and on the TLR4 activation downstream events are largely unknown. This study was aimed to explore whether carbocysteine, in a human bronchial epithelial cell line (16-HBE), counteracted some pro-inflammatory CSE-mediated effects. In particular, TLR4 expression, LPS binding, p21 (a senescence marker), IL-8 mRNA and release in CSE-stimulated 16-HBE as well as actin reorganization in neutrophils cultured with supernatants from bronchial epithelial cells which were stimulated with CSE and/or carbocysteine were assessed. TLR4 expression, LPS binding, and p21 expression were assessed by flow cytometry, IL-8 mRNA by Real Time PCR and IL-8 release by ELISA. Actin reorganization, a prerequisite for cell migration, was determined using Atto 488 phalloidin in neutrophils by flow cytometry and fluorescence microscopy. CSE increased: (1) TLR4, LPS binding and p21 expression; (2) IL-8 mRNA and IL-8 release due to IL-1 stimulation; (3) neutrophil migration. Carbocysteine in CSE stimulated bronchial epithelial cells, reduced: (1) TLR4, LPS binding and p21; (2) IL-8 mRNA and IL-8 release due to IL-1 stimulation; (3) neutrophil chemotactic migration. In conclusion, the present study provides compelling evidences that carbocysteine may contribute to control the inflammatory and senescence processes present in smokers.

Cigarette smoke increases BLT2 receptor functions in bronchial epithelial cells: in vitro and ex vivo evidence.

Leukotriene B(4) (LTB(4)) is a neutrophil chemotactic molecule with important involvement in the inflammatory responses of chronic obstructive pulmonary disease (COPD). Airway epithelium is emerging as a regulator of innate immune responses to a variety of insults including cigarette smoke, the major risk factor for COPD. In this study we have explored whether cigarette smoke extracts (CSE) or soluble mediators present in distal lung fluid samples (mini-bronchoalveolar lavages) from smokers alter the expression of the LTB(4) receptor 2 (BLT2) and peroxisome proliferator-activated receptor-α (PPAR-α) in bronchial epithelial cells. We also evaluated the effects of CSE on the expression of intercellular adhesion molecule 1 (ICAM-1) and on the binding of signal transducer and activator of transcription 1 (STAT-1) to ICAM-1 promoter as well as the adhesiveness of neutrophils to bronchial epithelial cells. CSE and mini-bronchoalveolar lavages from smokers increased BLT2 and ICAM-1 expression as well as the adhesiveness of neutrophils to bronchial epithelial cells and decreased PPAR-α expression. CSE induced the activation of STAT-1 and its binding to ICAM-1 promoter. These findings suggest that, in bronchial epithelial cells, CSE promote a prevalent induction of pro-inflammatory BLT2 receptors and activate mechanisms leading to increased neutrophil adhesion, a mechanism that contributes to airway neutrophilia and to tissue damage.

Efficacy of sublingual immunotherapy with grass allergens for seasonal allergic rhinitis: a systematic review and meta-analysis.

BACKGROUND: The benefit of sublingual immunotherapy (SLIT) with grass allergens for seasonal allergic rhinitis has been extensively studied, but data on efficacy are still equivocal. OBJECTIVE: To assess the effectiveness of SLIT with grass allergens in the reduction of symptoms and medication in patients with seasonal allergic rhinitis to grass pollen. METHODS: Computerized bibliographic searches of MEDLINE (1995-2010) were supplemented by hand searches of reference lists. Studies were included if they were double-blind randomized controlled trials (RCTs) comparing SLIT to placebo and if they included patients with history of allergy to grass pollen treated with natural grass pollen extracts. Nineteen RCTs with 2971 patients were analyzed. The outcomes assessed were symptom and medication scores. RESULTS: Using a random-effects model, SLIT with grass allergens significantly reduces both symptoms (standardized mean difference, -0.32; 95% CI, -0.44 to -0.21) and medication use (standardized mean difference, -0.33; 95% CI, -0.50 to -0.16) compared with placebo. The treatment is more efficacious in adults than in children. Prolonging duration of preseasonal treatment for more than 12 weeks improves the treatment efficacy. CONCLUSION: This meta-analysis found that SLIT with grass allergens is effective in patients with seasonal allergic rhinitis compared with placebo. The benefit is clinically modest, and criteria are needed to identify patients most likely to benefit from SLIT.

Pleural mesothelial cells express both BLT2 and PPARalpha and mount an integrated response to pleural leukotriene B4.

Leukotriene B(4) (LTB(4)) plays a crucial role in the recruitment of neutrophils into the pleural space. We identified for the first time the mechanisms by which LTB(4) interacts with mesothelial cells and recruits neutrophils in the pleural compartment. Primary pleural mesothelial cells express both the proinflammatory receptor for LTB(4) BLT2, and the anti-inflammatory receptor for LTB(4), PPARalpha. Parapneumonic pleural effusions highly increase BLT2 expression and, via BLT2 activation, increase the adhesion between mesothelial cells and neutrophils and the expression of ICAM-1 on mesothelial cells. The block of PPARalpha further increases both cell adhesion and ICAM-1 expression. BLT2 activation promotes the activation, on mesothelial cells, of STAT-1 but not the activation of NF-kappaB transcription factor. The increase of ICAM-1 expression is achieved via increased tyrosine phosphorylation activity since herbimycin, a tyrosine kinase inhibitor, reduces and since Na orthovanadate, a tyrosine phosphatase inhibitor, further increases ICAM-1 expression. This study demonstrates that pleural mesothelial cells, expressing both proinflammatory and anti-inflammatory LTB(4) receptors, are able to mount an integrated response to LTB(4) with a prevalence of BLT2 activities in the presence of an inflammatory milieu within the pleura.