Progress in the development of ß-lactams as N-Acylethanolamine Acid Amidase (NAAA) inhibitors: Synthesis and SAR study of new, potent N-O-substituted derivatives.

The anti-inflammatory effects resulting from raising the levels of palmitoylethanolamide (PEA), an endogenous bioactive lipid, led to envisage N-Acylethanolamine Acid Amidase (NAAA), the cysteine hydrolase mainly responsible for PEA degradation, as an attractive target for small molecule inhibitors. Previous work in our group identified serine-derived ß-lactams as potent and systemically active inhibitors of NAAA activity. Aiming to expand the SAR study around this class of compounds, we investigated the effect of the substitution on the endocyclic nitrogen by designing and synthesizing a series of N-substituted ß-lactams. The present work describes the synthesis of new N-O-alkyl and N-O-aryl substituted ß-lactams and reports the results of the structure activity relationship (SAR) study leading to the discovery of a novel, single-digit nanomolar NAAA inhibitor (37). Compound 37 was shown in vitro to inhibit human NAAA via S-acylation of the catalytic cysteine, and to display very good selectivity vs. human Acid Ceramidase, a cysteine amidase structurally related to NAAA. Preliminary in vivo studies showed that compound 37, administered topically, reduced paw edema and heat hyperalgesia in a carrageenan-induced inflammation mouse model. The high in vitro potency of 37 as NAAA inhibitor, and its encouraging in vivo activity qualify this compound as a new tool for the study of the role of NAAA in inflammatory and pain states.

Effects of peripheral FAAH blockade on NTG-induced hyperalgesia--evaluation of URB937 in an animal model of migraine.

BACKGROUND: Systemic nitroglycerin (NTG) activates brain nuclei involved in nociceptive transmission as well as in neuroendocrine and autonomic functions in rats. These changes are considered relevant for migraine because NTG consistently provokes spontaneous-like migraine attacks in migraineurs. Several studies have suggested a relationship between the endocannabinoid levels and pain mediation in migraine. URB937, a peripheral inhibitor of fatty acid amide hydrolase (FAAH)-the enzyme that degrades anandamide, produces analgesia in animal models of pain, but there is no information on its effects in migraine. AIM: We evaluated whether URB937 alters nociceptive responses in the animal model of migraine based on NTG administration in male rats, using the tail flick test and the plantar and orofacial formalin tests, under baseline conditions and after NTG administration. Furthermore, we investigated whether URB937 affects NTG-induced c-Fos expression in the brain. RESULTS: During the tail flick test, URB937 showed an antinociceptive effect in baseline conditions and it blocked NTG-induced hyperalgesia. URB937 also proved effective in counteracting NTG-induced hyperalgesia during both the plantar and orofacial formalin tests. Mapping of brain nuclei activated by NTG indicates that URB937 significantly reduces c-Fos expression in the nucleus trigeminalis caudalis and the locus coeruleus. CONCLUSIONS: The data suggest that URB937 is capable of changing, probably via indirect mechanisms, the functional status of central structures that are important for pain transmission in an animal model of migraine.

Effectiveness of anthracycline against experimental prion disease in Syrian hamsters.

Prion diseases are transmissible neurodegenerative conditions characterized by the accumulation of protease-resistant forms of the prion protein (PrP), termed PrPres, in the brain. Insoluble PrPres tends to aggregate into amyloid fibrils. The anthracycline 4'-iodo-4'-deoxy-doxorubicin (IDX) binds to amyloid fibrils and induces amyloid resorption in patients with systemic amyloidosis. To test IDX in an experimental model of prion disease, Syrian hamsters were inoculated intracerebrally either with scrapie-infected brain homogenate or with infected homogenate coincubated with IDX. In IDX-treated hamsters, clinical signs of disease were delayed and survival time was prolonged. Neuropathological examination showed a parallel delay in the appearance of brain changes and in the accumulation of PrPres and PrP amyloid.

Transformation of sulfated bile acids by human intestinal microflora.

The in vitro transformation, under anaerobic conditions, of 3- and 7-monosulfated and unsulfated bile acids, was studied in incubates of fecal flora from three healthy subjects. Chenodeoxycholic acid 7 alpha-sulfate and ursodeoxycholic acid 7 beta-sulfate were recovered unchanged, in all cultures, at the end of the incubation time. 3-Sulfated bile acids were metabolized in a different way by the three stool specimens. During the transformation of chenodeoxycholic acid 3-sulfate, desulfation, 7-dehydroxylation and 3-epimerization were observed. In contrast, 3-epimerization was not noticed when ursodeoxycholic acid 3-sulfate and lithocholic acid 3-sulfate were metabolized, the latter being principally transformed into delta 3-cholenic acid, probably by a bacterially mediated trans-elimination of sulfate group. The results obtained seem to prove that the presence of a SO3H group in 7-position usually hinders microbial transformations, which are not affected by a sulfate group in 3-position. Moreover, the 3-sulfated bile acids proved to be less sensitive to the microbial action than the corresponding unsulfated acids, with exception of lithocholic 3-sulfate.