title: Inhibitors of poly(ADP-ribose) polymerase-1 suppress transcriptional activation in lymphocytes and ameliorate autoimmune encephalomyelitis in rats.
abstract: 1. In the presence of genotoxic stress poly(ADP-ribose) polymerase-1 (PARP-1) leads to NAD(+) and ATP depletion, participating in the pathogenesis of several disorders including inflammation. Accordingly, chemical inhibitors of PARP-1 are efficacious anti-inflammatories, albeit the underlying molecular mechanisms are still under debate. 2. This study investigated the effect of the PARP-1 inhibitors 6(5H)-phenanthridinone and benzamide as well as that of benzoic acid, an inactive analogue of benzamide, on development of experimental allergic encephalomyelitis (EAE) in rats. Both 6(5H)-phenanthridinone and benzamide attenuated development of EAE, reducing clinical score, neuroimmune infiltration and expression of inflammatory mediators such as inducible nitric oxide synthase, interleukin-1beta and -2, cyclooxygenase-2, tumour necrosis factor-alpha and interferon-gamma in the spinal cord of myelin-immunized rats. Importantly, no evidence of NAD(+) and ATP depletion as well as poly(ADP-ribose) formation was detected in the spinal cord. 3. By contrast, a robust formation of poly(ADP-ribose) occurred in B- and T-cell areas in lymph nodes of myelin-immunized rats and was suppressed by the treatment with 6(5H)-phenanthridinone and benzamide. In cultures of activated rat lymphocytes, 6(5H)-phenanthridinone and benzamide reduced the DNA-binding activity of NF-kappaB and AP-1 and transcription of pro-inflammatory cytokines such as interleukin-2, interferon-gamma and tumour necrosis factor-alpha. 4. Notably, benzoic acid did not reproduce the in vivo and in vitro effects of its parent compound. 5. These findings indicate that PARP-1 promotes transcriptional activation in lymphocytes and inhibitors of its enzymatic activity are useful for the treatment of autoimmune disorders of the central nervous system.
authors.affiliation: Department of Preclinical and Clinical Pharmacology, University of Florence, Florence, Italy. alberto.chiarugi@umassmed.edu
authors.forename: Alberto
authors.initials: A
authors.lastname: Chiarugi
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D019817:Benzoic Acid / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000139:chemically induced / Q000517:prevention & control*; D007371:Interferon-gamma / Q000235:genetics; D007376:Interleukin-2 / Q000235:genetics; D008198:Lymph Nodes / Q000187:drug effects / Q000378:metabolism; D008214:Lymphocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009243:NAD / Q000378:metabolism; D010616:Phenanthrenes / Q000494:pharmacology; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D013997:Time Factors; D015533:Transcriptional Activation / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
chemical_list: D001549:Benzamides; D007376:Interleukin-2; D010616:Phenanthrenes; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D009243:NAD; C037689:benzamide; D007371:Interferon-gamma; D000255:Adenosine Triphosphate; D019817:Benzoic Acid; C040601:phenanthridone; D011065:Poly(ADP-ribose) Polymerases