New approaches for the discovery and development of innovative drugs for the treatment of neurodegeneratives diseases


The main goal of this project is to explore new strategies for the therapeutic treatment of neurodegenerative diseases, such as Alzheimer or Parkinson. The use of three different and complementary approaches (strategies) together with the crystallographic and computational studies of cannabinoid receptors, and the biological tests in animal models, will provide enough information to establish scientific basis about the use of cannabinoids for the treatment of neurodegenerative diseases. To this end, we propose the design, synthesis and biological evaluation (in vitro and in vivo) of new molecules with cannabinoid properties.

Endocannabinoid System

The endocannabinoid system is a complex organization that includes transmembrane receptors CB1 and CB2, their endogenous ligands (known as endocannabinoids), and their mechanisms of synthesis, transport and inactivation. The exogenous cannabinoid ligands, are those natural or synthetic structures which change in a positive (agonist) or negative (antagonist) way the cannabinoid receptors.

Neurodegenerative diseases

Neurodegenerative diseases are an increasing public concern, being currently the eighth cause of disease burden for developed regions. During the last years, several studies have showed the potential of the endocannabinoid system on neurodegenerative diseases, however these studies do not offer a complete understanding of the mechanisms involved and the possible application of cannabinoids for the therapeutic treatment of these diseases. Our goals in this project are the development of: i) CB1 antagonists, with antioxidant properties, for the treatment of Parkinson’s disease. ii) CB2 agonists and molecules with dual action (cannabinoid and cholinergic properties) for the treatment of Alzheimer’s disease.

Cannabis sativa

Phytocannabinoids, also called natural cannabinoids or classical cannabinoids, are a group of naturally occurring compounds isolated mainly from the plant Cannabis sativa L. These compounds are concentrated in a viscous resin that is produced in glandular structures known as trichomes. The main component is Δ9-THC, which was isolated and characterized in 1964. This compound is responsible for the psychoactive properties of cannabis, although it has many other therapeutic properties, such as analgesic, anti-inflammatory, antiemetic, muscle relaxant, antiasmatic, antispasmodic and antiproliferative. There are more than 70 cannabinoid compounds isolated from Cannabis sativa having different agonist and antagonist properties over cannabinoid receptors (CB1 and CB2).

Synthetic Cannabinoids

Non Classic cannabinoids as CP-55, 940 are similar to THC but without the pyran ring. In general these compounds show poor selectivity. Aminoalkylindoles as WIN 55212-2, potent CB1 and CB2 agonist, AM-630, the first CB2 selective antagonist of this class and AM-1241, potent selective CB2 agonist. Besides these groups there are other structures such as benzofurans (LY320135), diarilpirazoles (rimonabant, SR141716), sulfonamide derivatives, quinolinones derivatives (GW-842166X), etc. There are also some structures inspired in endogenous cannabinoids, such as the CB1 selective agonist O-1812.

Cannabinoid Receptors

As a first work in the cannabinoid field we carried out a modeling study of CBRs, using the X-ray structure of bovine Rodopsine (pdb code: 1f88) as structural template. Docking studies with the most representative cannabinoids, described as partial agonists or antagonists / inverse agonists, were performed. The results confirmed the existence of two binding sites on both receptors. While in the CB1R was observed a clear overlap of both sites, in CB2R, the sites are clearly distinct. In both sites, receptor-ligand interactions are governed by a combination of hydrogen bonds and aromatic interactions.


Biological studies

– The group of Prof. I. Martín-Fontelles (URJ) is a reference group in the study of the cannabinoid system with a wide experience in various aspects of biological research as reflected in its publications on topics such as pain, cardiovascular system and gastrointestinal system.

– The UCM´s group, headed by Prof. Fernández-Ruiz has experience on cannabinoids topic and their application on neurodegenerative diseases. One of their topics is focus on the study of the application of antagonist CB1 in the treatment of reduction of the motor activity due to the Parkinson disease, using an animal model.

– The HUFA´s group, headed by Prof. Romero, work for years in the role that the endogenous cannabinoid system (ECS) may play in Alzheimer’s disease (AD). Among the major contributions made by this group emphasizes the identification of the CB2 receptor as a potential therapeutic target in this pathology.

Cristalographics studies

– The group headed by Dr. Hermoso has a solid experience of more than 15 years in the macromolecular crystallography field.

Docking Studies

Docking studies with the most representative cannabinoids described as partial agonists or antagonists/inverse agonists, were performed using Flexidock program. FlexiDock software performs flexible docking using genetics algorithms. The results of these studies confirmed the existence of two binding sites on both CB1 and CB2. While in the CB1 receptor was observed a clear overlap of both sites, in CB2 receptor are clearly distinct. In both sites, receptor-ligand interactions are governed by a combination of hydrogen bonds and aromatic interactions. The results of these studies confirmed the existence of two binding sites on both receptors.

Strategy of Drug Design

In the design stage, we will use both traditional methods of molecular analogy with other known active compounds, and cheminformatic methods that include neural network and modeling (docking studies). All aimed at finding new drugs to be studied both in vitro to establish a possible mechanism of action, in vivo in animal models to establish their possible therapeutic application in AD and PD.

Homology Modeling

The homology modeling consists in several steps. The firs step is to obtain a correct sequence alignment of the target sequences with the homologous template, using program as CLUSTALW  followed by a manual adjustment of the multiple alignment sequence with the program SEAVIEW. From the best alignment, 3D models containing all non-hydrogen atoms are obtained automatically using the method implemented in MODELLER. The structurally variable regions (SVRs) as loops are built with the standard procedure in MODELLER and afterwards they are refined. After the refinement process the models are validated using the VERIFY ,PROCHECK and COMPARER programs.