• Magl

Facoltà di Farmacia
Corso di laurea in Chimica e tecnologia farmaceutica;
Relatore: prof.ssa C.Manera, dott.ssa F.Castelli;
SSD: CHIM 08
Candidato: Gianfilippo Martello
Titolo tesi: Design, synthesis and biological evaluation of heterocyclic derivatives as potential MAGL inhibitors.

INTRODUCTION
Monoacylglycerol lipase (MAGL) is a metabolizing enzyme which belongs to the endocannabinoid system. The endocannabinoid system includes the endogenous ligands: anandamide (AEA) and 2-arachidonoyl glycerol (2-AG) (Figure 1), the cannabinoid receptors CB1 and CB2, the anandamide transporter protein, and two metabolizing enzymes: fatty acid amide hydrolase (FAAH) which is involved in the inactivation of AEA and monoglyceride lipase (MAGL or MAGL) which is involved in the inactivation of 2-AG.1
2- AG is the natural ligand for CB1 and CB2 receptors even if it interacts predominantly with CB2 receptors, it exhibits lower affinity than AEA and it is considered the primary endogenous cannabinoid in the brain
.

Figure 1
Biological activities of 2-AG have been reported in: immune function, cell proliferation, embrio development, neuroprotection, immunomodulation, cardiovascular function and inflammatory responses.1
MAGL is a serine hydrolase belonging to the “α/β hydrolase fold” family characterized by a central β sheet core surrounded by a variable number of α helicals. The catalytic triad is formed by serine (S132), aspartic acid (D239) and histidine (H269) residues, in addition 3 cysteine residues appear to contribute to the regulation of MAGL functions (Figure 2).2, 3


Figure 2
MAGL is involved in the inactivation of 2-AG, in particular it catalyses the hydrolysis of 2-AG to fatty acid and glycerol (Figure 3).2,3

MAGL INHIBITORS
There are different kinds of MAGL inhibitors, the major-ones are: NON-SPECIFIC SERINE HYDROLASE INHIBITORS, INHIBITORS INSPIRED BY THE ENDOGENOUS SUBSTRATE and De novo INHIBITORS.4
The main therapeutic applications of MAGL inhibitors are:
1. NEUROPROTECTION : they can protect neurons from hypoxic injury and they can protect from cerebral ischemia;
2. FEEDING BEHAVIOUR: they can stimulate appetite, lipogenesis and fat accumulation;
3. Treatment of CANCER: they can inhibit the proliferation of certain cancer cell lines;
4. Treatment of GLAUCOMA: they can regulate intraocular pressure;
5. ANALGESIC EFFECTS.4

De novo INHIBITORS
Some inhibitors of MAGL have been recently described whose structures do not resemble any endogenous cannabinoid: URB754, URB602 (Figure 4), SAR629 and JZL184 (Figure 5c).
- URB754 was reported to inhibit 2-AG degradation through a non competitive and irreversible mechanism;4
- URB602 showed a lower capacity to disrupt MAGL hydrolysing activity;4
- Other de novo INHIBITORs are: JZL184 apiperidine derivate and SAR629, a piperazine derivative, Which exhibits interesting selectivity for MAGL over FAAH and showed a similar mechanism of inhibition. In particular, it is reported that SAR629 mechanism of inhibition mimics the pathway of 2-AG hydrolysis by MAGL by making a relatively stable carbamate adduct with the catalytic serine instead of the relatively labile ester adduct (Figure 5a and b). MAGL–SAR629 co-structure permits the identification of pharmacophoric points (Figure 5c): the carbonyl oxygen of the urea function seems necessary to create the only polar interaction between the inhibitor and the Ser-132 of the protein. One of the fluorophenyl groups probably interacts with some hydrophobic residues and the role of the piperazine is to orient the other moieties toward pharmacophoric points, so it could probably be replaced by other moieties;2











Figure 4

Figure 5
EXPERIMENTAL PART
My thesis is about the design, synthesis and biological evaluation of two different kind of derivatives as potential MAGL inhibitors:
1. Quinolin -2-one derivatives,
2. Pyridin -2-one derivatives.
Design, Syntesis and biological evaluation of quinolin, pyridine-2-one derivates as potential MAGL inhibitors.
On the basis of the knowledge reported before we decided to design the synthesis of structure A and B.


( )n ( ) n



A B
R1= ; R1= , ;


R2 = , ; R2= ;
n=0 n=0

- These compounds of series a and b could have the same interactions of compounds SAR629 and JZL with the active site of the enzyme, infact also for these compounds: the carbonyl oxygen of the carbamate functioncould create the polar interactions with Ser 132 of the protein, the fluorophenyl group could interact with some hydrophobic residues and the quinoline or piperidine ring constitute the linker between the two
- pharmacophore groups and permit the adeguate orientation into the active site.










SAR629