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Cell death is a common feature observed in neurodegenerative disorders, and is often associated with calpain activation and overproduction of reactive oxygen species (ROS). This study investigated the use of calpain inhibitors and antioxidants in combination to protect cells against necrosis. Maitotoxin (MTX), which induces a massive influx of calcium, was used to provoke neuronal cell death. This toxin increased, in a concentration-dependent manner, both calpain activity and ROS formation. Calpain inhibitors or antioxidants inhibited MTX-induced necrosis only marginally (below 20%), whereas their association protected against cell death by 40-66% in a synergistic manner. BN 82204, which possesses both calpain-cathepsin L inhibitory and antioxidant properties, and its acetylated pro-drug BN 82270, totally protected cells at 100 microm. The pro-drug BN 82270, which had better cell penetration, was twice as effective as the active principle BN 82204 in protecting glioma C6 or neuroblastoma SHSY5Y cells against death. These results suggest the potential therapeutic relevance of using a single molecule with multiple activities (cysteine protease inhibitor/antioxidant), and warrant further in vivo investigations in models of neuronal disorders.

Nitric oxide (NO) and reactive oxygen species (ROS) act independently as well as cooperatively to induce neuronal death in acute neurological disorders. Inhibition of neuronal nitric oxide synthase (nNOS) and inhibition of lipid peroxidation induced by ROS have both been proposed as neuroprotective strategies in stroke and trauma. Recently, in our laboratory, the combination of the two strategies was found to be synergistic in reducing neuronal damage. Here, we report that BN 80933 [( S )- N -{4-[4-[(3,4-dihydro-6-hydroxy-2,5,7,8-tetramethyl-2 H -1-benzopyran-2-yl)carbonyl]-1-piperazinyl]phenyl}-2-thiophenecarboximidamide], a compound that combines potent antioxidant and selective nNOS inhibitory properties in vitro , affords remarkable neuronal protection in vivo . Intravenous administration of BN 80933 significantly reduced brain damage induced by head trauma in mice, global ischemia in gerbils, and transient focal ischemia in rats. Treatment with BN 80933 (0.3–10 mg/kg) significantly reduced infarct volume (>60% protection) and enhanced behavioral recovery in rats subjected to transient (2-h) middle cerebral artery occlusion and 48-h or 7-day reperfusion. Furthermore, treatment with BN 80933 commencing up to 8 h after the onset of ischemia resulted in a significant improvement of neurological outcome. All these results indicate that BN 80933 represents a class of potentially useful therapeutic agents for the treatment of stroke or trauma and possibly neurodegenerative disorders that involve both NO and ROS.

The synthetic polyribonucleotide poly(A).poly(U) induces 2',5'-oligoadenylate synthetase activity in the murine macrophage cell line J774A1. The possible role of several cytokines involved in macrophage activation (i.e., IL-1, IL-6, TNF, and IFN) was examined in the present study. It was first demonstrated that among the anticytokine antibodies, only monoclonal antibodies directed against IL-6 inhibited the induction of 2',5'-oligoadenylate synthetase by poly(A).poly(U) in a dose-dependent manner. Moreover, it was established that poly(A).poly(U) elicited IL-6 production in J774A1 cells in a time-and dose-dependent manner. Consequently, the effect of IL-6 on 2',5'-oligoadenylate synthetase activity was studied. IL-6 either alone or in combination with IL-1 and TNF did not induce 2',5'-oligoadenylate synthetase activity. IL-6 did not potentiate IFN-gamma-induced 2'-5'-oligoadenylate synthetase activity. In contrast, addition of IL-6 to the incubation medium potentiated the stimulation of 2'-5'-oligoadenylate synthetase activity by IFN-alpha. These results suggest that IL-6 is a necessary but not sufficient factor in the induction of 2'-5'-oligoadenylate synthetase activity in the J774A1 cell line by poly(A).poly(U).

The development of l -dopa-induced dyskinesia (LID) remains a major problem in the long-term treatment of Parkinson’s disease (PD). This study aimed to assess the effect of the multitargeting molecule BN82451 on LID and to measure striatal mRNA expression of several genes in a rat model of PD. Rats were administered two unilateral injections of 6-OHDA in the striatum. After four weeks, the animals started a chronic daily treatment with increasing doses of l -dopa over a further four-week period. Over the course of l -dopa treatment, the rats developed abnormal involuntary movements (AIMs) classified as locomotive, axial, orolingual and forelimb dyskinesia. In animals rendered dyskinetic by l -dopa, administration of BN82451 at doses ranging from 1 to 10 mg/kg p.o. attenuated the severity of fully-established AIMs in a dose-related manner. This anti-dyskinetic effect could be achieved with lower doses of BN82451 administered sub chronically vs. acute single treatment. The improvement of AIMs is not due to a reduction in the general motor activity of dyskinetic rats. BN82451 treatment significantly reversed the overexpression of c-Fos, FosB and Arc mRNA associated with the dyskinesiogenic action of l -dopa. A significant correlation between the degree of overexpression of c-Fos, FosB and Arc mRNA and the dyskinesiogenic action of l -dopa was observed. The data demonstrate that BN82451 effectively attenuates LID and the associated molecular alterations in an animal model of PD and may represent a treatment option for managing dyskinesia.

Agmatine was about as potent as aminoguanidine to inhibit the activity of the inducible form of nitric oxide synthase (iNOS) in isolated rat aorta. Like aminoguanidine, agmatine was devoid of significant activity on the constitutive form of NOS. Agmatine inhibited the conversion of [3H] L -arginine in [3H] L -citrulline in partially purified iNOS from macrophages (IC50=262±39.9 μM). Thus, our data suggest that agmatine may act as endogenous inhibitor of iNOS.