Genomic and proteomic study to survey the mechanism of action of the anti-Parkinson's disease drug, rasagiline compared with selegiline, in the rat midbrain.

The novel anti-Parkinson's disease (PD) drug, rasagiline (N-propargyl-1-(R)-aminoindan), is a second generation of irreversible selective inhibitor of monoamine oxidase-B follows selegiline. In light of the recent large clinical study (phase III ADAGIO) reporting benefits in PD patients, it has been suggested that rasagiline could be the first PD treatment to receive the label neuroprotective "disease-modifying" drug. Indeed, rasagiline has been shown to have a broad neuroprotective activity against a variety of neurotoxins in preclinical models of neurodegenerative diseases and in cultured neuronal cells. In the present study, we have investigated the status of various molecular and biochemical markers in the rat midbrain following chronic treatments with rasagiline and selegiline, using proteomic and genomic analyses. Our findings demonstrated significant molecular changes induced by both drugs, at the protein and transcriptional levels, associated with neuronal differentiation, cell survival and death pathways, metabolism/oxidation stress, signaling system, and biomarkers of neurodegenerative disorders, which may be reflected in the clinical studies.

The neuroprotective effect of ladostigil against hydrogen peroxide-mediated cytotoxicity.

The multifunctional, anti-Alzheimer drug, ladostigil (TV3326) [(N-propargyl-(3R) aminoindan-5yl)-ethyl methyl carbamate] combines the neuroprotective effects of the anti-Parkinson drug, rasagiline, a selective monoamine oxidase (MAO)-B inhibitor, with the cholinesterase (ChE) inhibitory activity of rivastigmine in a single molecule. Ladostigil has been shown to possess potent antiapoptotic and neuroprotective activities in various oxidative insults in vitro and in vivo, such as prevention of the fall in mitochondrial membrane potential and regulation of Bcl-2 family proteins. In the present study, we demonstrate that ladostigil (1 microM) increased cell viability, associated with the increase of catalase activity and decrease of intracellular reactive oxygen species (ROS) production in human SH-SY5Y neuroblastoma cells exposed to (hydrogen peroxide) H(2)O(2). Furthermore, ladostigil significantly elevated mRNA levels of the antioxidants enzymes, catalase, NAD(P)H quinone oxidoreductase 1 (NQO1) and peroxiredoxin 1 (Prx 1) in H(2)O(2)-treated SH-SY5Y cells. Chronic treatment with ladostigil (1 mg/kg gavage per day for 30 days) markedly up-regulated mRNA expression levels of various antioxidant enzymes in aged rat hippocampus (e.g. glutathione peroxidase precursor (GSHPX-P), glutathione S-transferase (GST) and glucose-6-phosphate dehydrogenase (G6PD)). These findings indicate that in addition to its multiple neuroprotective characteristics, ladostigil also possesses antioxidant properties, which might be beneficial for the treatment of oxidative stress (OS) in aging and age-associated neurodegenerative diseases.

The application of proteomics and genomics to the study of age-related neurodegeneration and neuroprotection.

The present study aimed to acquire more information on aging-related alterations, using proteomic and genomic analyses of hippocampus from young (8 months) and old (27 months) rats. In the old rats, the proteomic analysis identified changes in proteins related to the iron-mediated oxidative stress (OS) pathway, including reduction in antioxidant enzymes (e.g., peroxiredoxin, cytochrome c oxidase) and induction of ferritin. Furthermore, the neurofilament light peptide, associated with neurodegenerative processes, was enhanced and binding/ chaperone proteins were altered in old vs. young rats. At the genes levels, significant molecular changes related to neurodegeneration were identified in aged rat hippocampus. Thus, the effects of the potent neuroprotective compounds, the anti-Parkinson drug, rasagiline and the anti-Alzheimer drug, ladostigil (1 mg/kg, for 30 days) on gene expression in the hippocampus were further investigated. Both drugs reversed the effect of aging on the expression of various mitochondrial and key regulator genes involved in neurodegeneration, cell survival, synaptogenesis, oxidation, and metabolism. These results support the hypothesis that OS and mitochondrial dysfunction may play a pivotal role in aging and age-associated neurodegenerative diseases, and can serve as potential clinical targets for future therapy.

The neurochemical and behavioral effects of the novel cholinesterase-monoamine oxidase inhibitor, ladostigil, in response to L-dopa and L-tryptophan, in rats.

The novel drugs, ladostigil (TV3326) and TV3279, are R and S isomers, respectively, derived from a combination of the carbamate cholinesterase (ChE) inhibitor, rivastigmine, and the pharmacophore of the monoamine oxidase (MAO) B inhibitor, rasagiline. They were developed for the treatment of comorbidity of dementia with Parkinsonism. In the present study, we determined the effects of these drugs on both aminergic neurotransmitter levels and motor behavioral activity in naïve and in L-dopa- or L-tryptophan-induced rats. Chronic treatment of rats with ladostigil (52 mg kg(-1) for 21 days) inhibited hippocampal and striatal MAO A and B activities by >90%, increased striatal levels of dopamine and serotonin, and inhibited striatal ChE activity by approximately 50%. Chronic TV3279 (26 mg kg(-1) for 21 days) similarly inhibited approximately 50% of striatal ChE activity, but did not affect MAO activity or amine levels. In sharp contrast to the inductive effect of the MAO A/B inhibitor, tranylcypromine (TCP), on stereotyped hyperactivity in response to L-dopa (50 mg kg(-1)) or L-tryptophan (100 mg kg(-1)), ladostigil completely inhibited these behavioral hyperactivity syndromes. Accordingly, acute rivastigmine (2 mg kg(-1)) and chronic TV3279 abolished the ability of TCP to initiate L-dopa-induced hyperactivity, while scopolamine (0.5 mg kg(-1)) reversed the inhibitory effect of chronic ladostigil on L-dopa-induced hyperactivity, suggesting that ladostigil may attenuate successive locomotion by activating central cholinergic muscarinic receptors.Finally, while chronic ladostigil administration to naïve rats resulted in preserved spontaneous motor behavior, acute treatment with ladostigil decreased motor performance, compared to control animals. In contrast, chronic as well as acute treatments with TV3279 reduced spontaneous motor activity. Thus, the aminergic potentiation by ladostigil may counteract its cholinergic inhibitory effect on spontaneous motor behavior. Our results suggest that potentiation of both aminergic and cholinergic transmission systems by ladostigil contributes equally to motor behavior performance, which is substantially impaired in comorbidity of dementia with Parkinsonism including dementia with Lewy bodies (DLB).

Characterization of the differentiated antioxidant profile of human saliva.

Saliva is armed with various defense mechanisms, such as the immunological and enzymatic defense systems. In addition, saliva has the ability to protect the mucosa against mechanical insults and to promote its healing via the activity of epidermal growth factor. However, another defense mechanism, the antioxidant system, exists in saliva and seems to be of paramount importance. The most interesting finding of the present study was the demonstration of the existence of much higher concentrations of the various salivary molecular and enzymatic antioxidant parameters in the parotid saliva compared with the submandibular/sublingual saliva. For example, peroxidase, superoxide dismutase, uric acid, and total antioxidant status were higher in resting parotid saliva compared with resting submandibular/sublingual saliva by 2405, 235, 245, and 147%, respectively. Another important finding was the distinction between the salivary antioxidant system and the immunological and enzymatic protective systems, as represented by the salivary concentrations of secretory IgA and lysozyme, respectively. These findings suggest that the profound antioxidant capacity of saliva secreted from parotid glands is related either to the different physiological demands related to eating (parotid predominance), to oral integrity maintenance (submandibular/sublingual predominance), or to the high content of deleterious redox-active transitional metal ions present in parotid saliva. This also may signify that our oral cavity environment is only partially protected against oxidative stress during most of the day and night.