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cAMP plays a significant role in signal transduction pathways controlling multiple cellular processes such as inflammation and immune regulation. cAMP levels are regulated by a family of phosphodiesterases (PDEs). We have studied the effects of a novel PDE7 inhibitor (PDE7i) treatment on mice with experimental autoimmune encephalomyelitis (EAE) a model of multiple sclerosis (MS) and compared it with another PDE7i. EAE was induced by immunizing C57BL/6J mice with myelin oligodendrocyte glycoprotein (MOG 35-55 ) peptide. Mice were treated daily either from disease onset or from disease peak with each PDE7i and with fingolimod (used in therapy for MS patients) and disease evolution was followed by clinical symptoms. We examined neuropathology of spinal cord, ex vivo lymphocyte proliferation by [ 3 H]-thymidine incorporation, TNFα by ELISA and cAMP-PDE mRNAs expression by in situ hybridization histochemistry (ISHH) in spinal cord of EAE mice treated with both PDE7 inhibitors. Treatment of EAE mice with the novel PDE7i, VP3.15 showed more efficacy in reducing clinical signs at 10 mg kg −1 than the other PDE7i, BRL50481 and similar to fingolimod. VP3.15 acts on peripheral lymphocytes inhibiting their proliferation and TNFα secretion in a dose-dependent manner. PDE7i treatment alters the levels of PDE4B and PDE7 mRNA expression in EAE mice spinal cord. Given the interest in the development of new drugs for MS, including PDE7i as anti-inflammatory drugs, it is important to study the role played by PDE7 in neurodegenerative diseases with inflammatory component to better understand the beneficial and detrimental effects of a future therapy.

Acetylcholine (ACh) is involved in the modulation of the inflammatory response. ACh levels are regulated by its synthesizing enzyme, choline acetyltransferase (ChAT), and by its hydrolyzing enzymes, mainly acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). A more comprehensive understanding of the cholinergic system in experimental autoimmune encephalomyelitis (EAE) disease progression could pave the path for the development of therapies to ameliorate multiple sclerosis (MS). In this work, we analyzed possible alterations of the CNS cholinergic system in the neuroinflammation process by using a MOG‐induced EAE mice model. MOG‐ and vehicle‐treated animals were studied at acute and remitting phases. We examined neuropathology and analyzed mRNA expression of ChAT, AChE and the α7 subunit of the nicotinic acetylcholine receptor (α7nAChR), as well as AChE and BuChE enzyme activities, in brain and spinal cord sections during disease progression. The mRNA expression and enzyme activities of these cholinergic markers were up‐ or down‐regulated in many cholinergic areas and other brain areas of EAE mice in the acute and remitting phases of the disease. BuChE was present in a higher proportion of astroglia and microglia/macrophage cells in the EAE remitting group. The observed changes in cholinergic markers expression and cellular localization in the CNS during EAE disease progression suggests their potential involvement in the development of the neuroinflammatory process and may lay the ground to consider cholinergic system components as putative anti‐inflammatory therapeutic targets for MS., This work was supported by grants awarded by Fondazione Italiana Sclerosi Multipla (FISM 2013/R/25) to A.M.T, by Instituto de Salud Carlos III, PI-10/01874 and PI-15/00148, cofinanced by the European Regional Development Fund.,“Una manera de hacer Europa” and by the Generalitat de Catalunya (SGR2014/798) to G.M. GDP was supported by ERASMUS/ERASMUS+ project from Sapienza, University of Rome and by Torno Subito project from Regione Lazio, Italy. MDB was supported by FISM, and Ateneo Sapienza, University of Rome and the travel grant was supported by CIB (Consorzio Interuniversitario Biotecnologie). VG and SS were supported by FISM and University of Chieti-Pescara G. D’Annunzio.

Phosphodiesterase (PDE) 7 is involved in proinflammatory processes, being widely expressed both on lymphocytes and on certain brain regions. Specific inhibitors of PDE7 have been recently reported as potential new drugs for the treatment of neurological disorders because of their ability to increase intracellular levels of cAMP and thus to modulate the inflammatory process, as a neuroprotective well-established strategy. Multiple sclerosis is an unmet disease in which pathologies on the immune system, T-cells, and specific neural cells are involved simultaneously. Therefore, PDE7 inhibitors able to interfere with all these targets may represent an innovative therapy for this pathology. Here, we report a new chemically diverse family of heterocyclic PDE7 inhibitors, discovered and optimized by using molecular modeling studies, able to increase cAMP levels in cells, decrease inflammatory activation on primary neural cultures, and also attenuate the clinical symptoms in the experimental autoimmune encephalomyelitis (EAE) mouse model. These results led us to propose the use of PDE7 inhibitors as innovative therapeutic agents for the treatment of multiple sclerosis. © 2012 American Chemical Society., The authors gratefully acknowledge the financial support of Ministry of Science and Innovation (MICINN), projects nos. SAF2009-13015-C02-01, SAF2009-13015-C02-02, SAF2010-16365, SAF2009-1152, and PI10-01874; Instituto de Salud Carlos III (ISCiii), project no. RD07/0060/0015 (RETICS program) and CIBERNED; Fundación Española para la Ciencia y la Tecnología (FECYT), project no. FCT-09-INC-0367. M.R. and D. I. P. acknowledge pre- and post-doctoral fellowship from the CSIC (JAE program) respectively.

El pdf del artículo es el manuscrito de autor.-- et al., A neural network model has been developed to predict the inhibitory capacity of any chemical structure to be a phosphodiesterase 7 (PDE7) inhibitor, a new promising kind of drugs for the treatment of neurological disorders. The numerical definition of the structures was achieved using CODES program. Through the validation of this neural network model, a novel family of 5-imino-1,2,4-thiadiazoles (ITDZs) has been identified as inhibitors of PDE7. Experimental extensive biological studies have demonstrated the ability of ITDZs to inhibit PDE7 and to increase intracellular levels of cAMP. Among them, the derivative 15 showed a high in vitro potency with desirable pharmacokinetic profile (safe genotoxicity and blood brain barrier penetration). Administration of ITDZ 15 in an experimental autoimmune encephalomyelitis (EAE) mouse model results in a significant attenuation of clinical symptoms, showing the potential of ITDZs, especially compound 15, for the effective treatment of multiple sclerosis. © 2012 American Chemical Society., The authors gratefully acknowledge the financial support of Ministry of Science and Innovation (MICINN) projects nos. SAF2009-13015-C02-01, SAF2009-13015-C02-02, PI10-01874 and CTQ2009-07664; Instituto de Salud Carlos III (ISCiii) projects RD07/0060/0015 (RETICS program) and CIBERNED; Fundación Española para la Ciencia y la Tecnología (FECYT) project no. FCT-09-INC-0367; Programa de cooperación bilateral CSIC-Universidad de la República (2009UY0006).