Jean-Gregoire Marin

BN 80933 inhibits F2-isoprostane elevation in focal cerebral ischaemia and hypoxic neuronal cultures.

Formationofthelipidperoxidationproduct8-epi-prostaglandin2α (8-epi-PGF2α) a bioactive marker of oxidative stress, was quantified in in vitro and in vivo models of neuronal death. In culture media of primary rat cortical neurones exposed to hypoxia followed by reoxygenation, a 3.7-fold increase of 8-epi-PGF2α concentration was observed in comparison to control cells. In rats submitted to 2 h middle cerebral artery occlusion followed by a 22 h reperfusion period, a 27-fold increase of 8-epi-PGF2α was observed in the ischaemic hemisphere compared with the corresponding hemisphere of shamoperated rats. Treatment with the neuroprotective agent BN 80933 significantly reduced both 8-epi-PGF2α elevations in vitro and in vivo. These data suggest that 8-epi-PGF2α elevations might reflect the damaging free radical overproduction and subsequent lipid peroxidation during neuronal injury induced by hypoxia and ischaemia. Inhibition of 8-epi-PGF2α elevations participates to the neuroprotective effects of BN 80933.

Calpain inhibitors and antioxidants act synergistically to prevent cell necrosis: effects of the novel dual inhibitors (cysteine protease inhibitor and antioxidant) BN 82204 and its pro‐drug BN 82270

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 µm. 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.

In vitro antioxidant neuroprotective activity of BN 80933, a dual inhibitor of neuronal nitric oxide synthase and lipid peroxidation.

Abstract: BN 80933, a dual inhibitor of neuronal nitric oxide synthase and lipid peroxidation, prevents in vivo brain ischemic/reperfusion injury. In the present study, BN 80933 was shown to protect neurons from hypoxia‐induced cell death in primary cultures of cortical neurons. BN 80933 prevented lactate dehydrogenase activity elevation induced by hypoxia, displaying an IC50 value of 0.15 ± 0.05 μM. This effect was likely due to the antioxidant properties of BN 80933 because Trolox, but not NG‐nitro‐L‐arginine, also elicited protection. The antioxidant property of BN 80933 was then further investigated on HT‐22 cells subjected to buthionine sulfoximine‐ or glutamate‐induced glutathione depletion. The relative order of potency of the various compounds to inhibit oxidative stress‐induced neuronal death (BN 80933 > U104067 > butylated hydroxytoluene > 17β‐estradiol > Trolox > vitamin E) correlated with their ability to inhibit brain membrane lipid peroxidation (correlation coefficient = 0.939). BN 80933 afforded protection even when added 6 h after glutamate exposure. BN 80933 did not reverse intracellular glutathione depletion but prevented elevation of the level of 8‐epiprostaglandin F2α (8‐isoprostane), which appeared to be a delayed phenomenon. In conclusion, BN 80933 induces a potent cytoprotection that may be mediated by inhibition of delayed lipid peroxidation.

BN82451 attenuates l-dopa-induced dyskinesia in 6-OHDA-lesioned rat model of Parkinson’s disease

The development of L-dopa-induced dyskinesia (LID) remains a major problem in the long-term treatment of Parkinsons 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.