PROYECTO FONDECYT DE INICIACIÓN EN INVESTIGACIÓN 2013 PROPOSAL ABSTRACT Name Principal ZOLEZZI MORAGA JUAN MANUEL Investigator PEROXISOME PROLIFERATOR-ACTIVATED RECEPTORS (PPARS) AS POTENTIAL TARGETS AGAINST OXIDATIVE STRESS- Proposal Title DERIVED DAMAGE ON THE BLOOD-BRAIN BARRIER: LIMITING NEURODEGENERATIVE DISORDERS COLLATERAL DAMAGE
The Blood-brain barrier (BBB) has been described as a convergent point of several
neurodegenerative disorders, such as Alzheimer’s, Parkinson’s and Huntington’s diseases. Indeed, despite each of these disorders has its own etiology and key hallmarks, the health or integrity of the BBB has often been shown to be compromised and the severity of changes observed usually relates to the progression of the disease. Actually, there is an increasing interest on directed neurodegenerative disorders therapies development, which will certainly depends on the ability of potential molecules to cross the BBB. Thus, further studies regarding the BBB functionality under healthy and pathologic conditions seems quite necessary. In fact, the current available BBB models include non-human and human-derived models, which could be further divided, according to the origin of the blood vessels, into non-cerebral or cerebral endothelial models. However, only some of them actually are able to reflect the main characteristics of the functional BBB, such as structural proteins, transporters or electrical resistance index (TEER). This situation suggests that BBB models development-oriented research is still necessary in order to provide more accurate biological tools for drug research.
On the other hand, several neurodegenerative disorders have the oxidative stress as a key
factor of the neuronal damage. Indeed, several studies have correlated increases reactive oxygen species (ROS) production with cellular damage. We have conducted several experiments showing that peroxisome proliferator-activated receptors (PPARs)-agonist are able to protect neurons from oxidative challenge in vitro and to improve neurodegenerative markers in vivo. We have recently suggested that part of the benefits observed after PPARs-agonists treatment against neurodegenerative process are due to improvements in the BBB health and functionality. Thus, here it is hypothesize that PPARs-agonists are able to prevent oxidative stress-derived BBB damage through increased cell antioxidant capacity; and to an improved BBB trafficking, because of several transporters proteins up-regulation. Then, the development of a reliable BBB model which allows addressing whether PPARs-agonists treatment, such as Pioglitazone (PPARγ agonist) and WY14643 (PPARα agonist), is able to protect BBB integrity and functionality from oxidative stress, emerge as a fundamental objective of the proposed project. In order to do so, it is proposed (1) to establish and characterizes in vitro BBB models from primary rat brain microvascular endothelial cells (RBMEC) and commercial human brain microvascular endothelial cells (HBMEC), which allow identify the base line of these BBB models and the differences between animal and human derived BBB models. Additionally, develop a complex BBB model, through astrocytes-endothelial cells co-culture, will increase model validity and will provide more accurate measures of cellular and molecular parameters. Moreover, with these tools and by means of Immunocytochemistry, Immunoblotting, real time RT-PCR and TEER analysis it will be possible (2) to assess the molecular changes that take places after the BBB models exposure to oxidative stressor stimuli, such as H2O2. Finally, we will be able (3) to evaluate the effects derived of PPARs-agonist treatment on several cellular and molecular markers of the BBB model as well as on its functionality against oxidative stress.
We believe that the knowledge derived from this kind of studies will help not only to understand
why several drugs fail when transferred from in vitro or in vivo neurodegenerative disease models to real patients, but also to open a new multidisciplinary research area oriented to applied investigations, such as drug discovery.
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