P. Picone

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 β peptide (Aβ), an important component in Alzheimers disease (AD) pathogenesis, and Aβ 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 Aβ. In particular we review data concerning Aβ 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.

Toxicity of recombinant β-amyloid prefibrillar oligomers on the morphogenesis of the sea urchin Paracentrotus lividus

A distinctive feature of Alzheimers disease is the deposition of amyloid β‐protein (Aβ) in senile or diffuse plaques. The 42 residue β‐peptide (Aβ42) is the predominant form found in plaques. In the present work we report a high‐yield expression and purification method of production of a recombinant Aβ42. The purified recombinant peptide shows characteristics similar to the synthetic human peptide. Different size aggregates, either small oligomers or larger aggregates, were obtained upon dissolving the recombinant Aβ42 peptide under different conditions at pH 7.2 or pH 3, respectively. We report a new toxicity assay on the morphogenic development of the sea urchin Paracentrotus lividus and study the toxicity of the two kinds of aggregates. Despite the difference between the ionic strength of human extracellular fluid (0.154 mol/l) and artificial sea water (0.48 mol/l), toxicity data collected in this system have an intrinsic relevance. The different ionic strength, in fact, could change the kinetics of oligomer formation, but the effect of morphogenic development reported here is related to the final oligomer sizes. Results of the toxicity assay of Aβ42 on sea urchin development also show a dose‐dependent effect. After only 4 h of embryo development, one can note morphological defects in the cell membrane. Retardation of the embryos development, along with cellular disorders visible inside the blastocoele, can be observed after 1 day of development. Cellular degeneration in two different pathological phenotypes—the occluded blastulae and the occluded prism—is present after 48 h of development. Results show that a greater effect on cell death is induced by the small oligomers stabilized under physiological conditions than at acid pH. In this case only occluded blastulae are found after 48 h of development.—Carrotta, R., Di Carlo, M., Manno, M., Montana, G., Picone, P., Romancino, D., San Biagio, P. L. Toxicity of recombinant β‐amyloid prefibrillar oligomers on the morphogenesis of the sea urchin Paracentrotus lividus. FASEB J. 20, E1301–E1308 (2006)

Inflammatory Mediators as Biomarkers in Brain Disorders

Neurodegenerative diseases such as Alzheimer, Parkinson, amyotrophic lateral sclerosis, and Huntington are incurable and debilitating conditions that result in progressive death of the neurons. The definite diagnosis of a neurodegenerative disorder is disadvantaged by the difficulty in obtaining biopsies and thereby to validate the clinical diagnosis with pathological results. Biomarkers are valuable indicators for detecting different phases of a disease such as prevention, early onset, treatment, progression, and monitoring the effect of pharmacological responses to a therapeutic intervention. Inflammation occurs in neurodegenerative diseases, and identification and validation of molecules involved in this process could be a strategy for finding new biomarkers. The ideal inflammatory biomarker needs to be easily measurable, must be reproducible, not subject to wide variation in the population, and unaffected by external factors. Our review summarizes the most important inflammation biomarkers currently available, whose specificity could be utilized for identifying and monitoring distinctive phases of different neurodegenerative diseases.

Insulin Promotes Survival of Amyloid-Beta Oligomers Neuroblastoma Damaged Cells via Caspase 9 Inhibition and Hsp70 Upregulation

Alzheimers disease (AD) and type 2 diabetes are connected in a way that is still not completely understood, but insulin resistance has been implicated as a risk factor for developing AD. Here we show an evidence that insulin is capable of reducing cytotoxicity induced by Amyloid-beta peptides (A-beta) in its oligomeric form in a dose-dependent manner. By TUNEL and biochemical assays we demonstrate that the recovery of the cell viability is obtained by inhibition of intrinsic apoptotic program, triggered by A-beta and involving caspase 9 and 3 activation. A protective role of insulin on mitochondrial damage is also shown by using Mito-red vital dye. Furthermore, A-beta activates the stress inducible Hsp70 protein in LAN5 cells and an overexpression is detectable after the addition of insulin, suggesting that this major induction is the necessary condition to activate a cell survival program. Together, these results may provide opportunities for the design of preventive and therapeutic strategies against AD.

Curcumin induces apoptosis in human neuroblastoma cells via inhibition of AKT and Foxo3a nuclear translocation.

Abstract Neuroblastoma (NB) is one of the most frequent extracranial solid tumors in children. It accounts for 8–10% of all childhood cancer deaths, and there is a need for development of new drugs for its treatment. Curcumin (diferuloylmethane), a major active component of turmeric (Curcuma longa), has been shown to exert anti-tumor activity on NB, but the specific mechanism by which curcumin inhibits cancer cells proliferation remains unclear. In the present study, we investigated the anti-proliferative effect of curcumin in human LAN5 NB cells. Curcumin treatment causes a rapid increase in reactive oxygen species and a decrease in the mitochondrial membrane potential—events leading to apoptosis activation. Furthermore, curcumin induces decrease in haet shock protein (Hsp)60 and hexokinase II mitochondrial protein levels and increase in the pro-apoptotic protein, bcl-2 associated death promoter (BAD). Moreover, we demonstrate that curcumin modulates anti-tumor activity through modulation of phosphatase and tensin homolog deleted on chromosome 10 and consequential inhibition of the survival Akt cell-signaling pathway. Inhibition of Akt causes its translocation into the cytoplasm and import of Foxo3a into the nucleus where it activates the expression of p27, Bim, and Fas-L pro-apoptotic genes. Together, these results take evidence for considering curcumin as a potential therapeutic agent for patients with NB.

Curcumin Entrapped Into Lipid Nanosystems Inhibits Neuroblastoma Cancer Cell Growth and Activates Hsp70 Protein

Department of Electrical Engineering, Indian Institute of Technology, Kharagpur 721 302, India, Electrical Engineering Division, Engineering Department, University of Cambridge, 9 J.J. Thomson Avenue, Cambridge CB3 0FA, UK, Faculty of Electrical Engineering, Universiti Teknologi Malaysia, UTM Skudai 81310, Johor, Malaysia, Department of Physics, Indian Institute of Technology, Mumbai 400 076, India, Division of Engineering and Physics, Wilkes University, Wilkes-Barre, PA18707, USA

Photo-inhibition of Aβ fibrillation mediated by a newly designed fluorinated oxadiazole

Uncontrolled aggregation of amyloid beta peptide (Aβ) is the main cause of Alzheimers disease. Therapeutic approaches to intervention in amyloid diseases include the use of small molecules able to stabilize the soluble Aβ conformation, or to redirect the amyloidogenic pathway towards non-toxic and non-fibrillar states. Fluorometric measurements revealed that 3-(4′-trifluoromethylphenyl)-5-(4′-methoxyphenyl)-1,2,4-oxadiazole, when irradiated, is able to interact with the monomeric Aβ peptide readdressing the aggregation pathway toward the formation of amorphous aggregates as evidenced by CD, AFM, and SAXS measurements. We hypothesize that this compound, under radiation, forms a reactive intermediate that sticks on the Aβ peptide by interfering with its fibrillation process. Cytotoxicity assays performed on LAN5 neuroblastoma cells suggest that the presence of oxadiazole reduces the toxicity of Aβ. This finding might be the start of innovative therapies against Alzheimers disease.

Alzheimer’s Disease and Type 2 Diabetes: Different Pathologies and Same Features

Protein aggregation is a very fascinating matter due to its implication in many human neurodegenerative diseases and its relevance in food and pharmaceutical industries. In some cases, the aggregation of protein is a natural phenomenon occurring in living organisms. For example, in the reaction leading from the globular (G) monomeric actin to its polymeric fibrillar (F) structure (Morris et al., 2009):

Effects of the Aphanizomenon flos-aquae Extract (Klamin®) on a Neurodegeneration Cellular Model

Cyanobacteria have been recognized as a source of bioactive molecules to be employed in nutraceuticals, pharmaceuticals, and functional foods. An extract of Aphanizomenon flos-aquae (AFA), commercialized as Klamin®, was subjected to chemical analysis to determine its compounds. The AFA extract Klamin® resulted to be nontoxic, also at high doses, when administered onto LAN5 neuronal cells. Its scavenging properties against ROS generation were evaluated by using DCFH-DA assay, and its mitochondrial protective role was determined by JC-1 and MitoSOX assays. Klamin® exerts a protective role against beta amyloid- (Aβ-) induced toxicity and against oxidative stress. Anti-inflammatory properties were demonstrated by NFβB nuclear localization and activation of IL-6 and IL-1β inflammatory cytokines through ELISA. Finally, by using thioflavin T (ThT) and fluorimetric measures, we found that Klamin® interferes with Aβ aggregation kinetics, supporting the formation of smaller and nontoxic structures compared to toxic Aβ aggregates alone. Altogether, these data indicate that the AFA extract may play a protective role against mechanisms leading to neurodegeneration.