Targeting neonatal ischemic brain injury with a pentapeptide-based irreversible caspase inhibitor

Brain protection of the newborn remains a challenging priority and represents a totally unmet medical need. Pharmacological inhibition of caspases appears as a promising strategy for neuroprotection. In a translational perspective, we have developed a pentapeptide-based group II caspase inhibitor, TRP601/ORPHA133563, which reaches the brain, and inhibits caspases activation, mitochondrial release of cytochrome c, and apoptosis in vivo. Single administration of TRP601 protects newborn rodent brain against excitotoxicity, hypoxia-ischemia, and perinatal arterial stroke with a 6-h therapeutic time window, and has no adverse effects on physiological parameters. Safety pharmacology investigations, and toxicology studies in rodent and canine neonates, suggest that TRP601 is a lead compound for further drug development to treat ischemic brain damage in human newborns.

Docosahexaenoic acid-rich phospholipid supplementation: effect on behavior, learning ability, and retinal function in control and n-3 polyunsaturated fatty acid deficient old mice

This study investigated the effects of docosahexaenoic acid (DHA)-rich phospholipid supplementation on behavior, electroretinogram and phospholipid fatty acid (PUFA) composition in selected brain regions and retina in old mice. Two groups of mice were fed a semisynthetic balanced diet or a diet deficient in alpha-linolenic acid. At the age of 8 months, half of each diet group was supplemented with DHA. In the open field, no differences in motor or exploratory activities were observed between the four diet groups. In the light/dark test of anxiety, the time spent in the light compartment was significantly higher in both supplemented groups than in control and deficient groups. Learning performance in the Morris water maze was significantly impaired in deficient old mice, but was completely restored by the phospholipid supplementation. The electroretinogram showed a significant alteration of a- and b-wave amplitudes in control compared to deficient mice. Phospholipid supplementation induced a significant increase of b-wave amplitude in both control and deficient groups and restored normal fatty acid composition in brain regions and retina in deficient mice. DHA-rich phospholipids may improve learning ability, visual function and reverse biochemical modifications in old mice fed an n-3 polyunsaturated fatty acid-deficient diet; they also may improve visual function in old mice fed a balanced diet.

Influence of social isolation and 6-OHDA lesion on the effects of quinelorane

The sensitivity of the response to the preferential dopaminergic D3 (DAD3) receptor agonist, quinelorane, was compared in mice housed socially and in mice isolated for 4 weeks. Quinelorane (1, 5, 10, 50 and 100 microg/kg) was administered intraperitoneally. Motor activity was measured for 60 min posttreatment. Rectal temperature was measured prior to and 1 h following the administration of quinelorane (10, 50 and 100 microg/kg i.p.). Quinelorane significantly and dose-dependently decreased locomotor activity in social and in isolated mice. The locomotor activity of isolated mice was significantly lower than that of social mice, but isolation had no effect on quinelorane-induced hypomotility. Quinelorane decreased dose-dependently rectal temperature in isolated and social mice, but isolation had no effect on quinelorane-induced decrease in rectal temperature. The lesions of dopaminergic terminals with intracerebroventricular administration of 6-OHDA decreased the dopamine (DA) level by 93% in the nucleus accumbens and by 91% in the corpus striatum; these lesions impaired neither the hypolocomotion nor the hypothermia induced by quinelorane. Thus, it may be concluded that social isolation has no influence on the quinelorane-induced decreases in rectal temperature and in locomotor activity and that the DA receptors involved in these effects of quinelorane are located postsynaptically.

Enhanced delivery of doxorubicin into the brain via a peptide-vector-mediated strategy: saturation kinetics and specificity

Doxorubicin delivery to the brain is often restricted because of the poor transport of this therapeutic molecule through the blood-brain barrier (BBB). To overcome this problem, we have recently developed a technology, Pep:trans, based on short natural-derived peptides that are able to cross efficiently the BBB without compromising its integrity. In this study, we have used the in situ mouse brain perfusion method to evaluate the brain uptake of free and vectorized doxorubicin. Doxorubicin was coupled covalently to small peptide vectors: L-SynB1 (18 amino acids), L-SynB3 (10 amino acids), and its enantio form D-SynB3. We first confirmed the very low brain uptake of free radiolabeled doxorubicin, which is most likely due to the efflux activity of the P-glycoprotein at the level of the BBB. Vectorization with either L-SynB1, L-SynB3, or D-SynB3 significantly increased the brain uptake of doxorubicin (about 30-fold). We also investigated the mechanism of transport of vectorized doxorubicin. We show that vectorized doxorubicin uses a saturable transport mechanism to cross the BBB. The effect of poly(L-lysine) and protamine, endocytosis inhibitors, on the transport across the brain was also investigated. Both inhibitors reduced the brain uptake of vectorized doxorubicin in a dose-dependent manner. These studies indicate that the transport of vectorized doxorubicin appears to occur via an adsorptive-mediated endocytosis.

Nutritional (n-3) polyunsaturated fatty acids influence the behavioral responses to positive events in mice

The effect of (n-3) polyunsaturated fatty acid (PUFA) diet deficiency on behavioural responses to appetitive events was assessed in OF1 mice. Pups fed the same diet (deficient in alpha-linolenic acid or a standard control diet) as their dams were used aged 7 to 11 weeks. In a free choice model, the preference for a sucrose solution in both males and females was significantly lower in deficient than in control mice. Morphine conditioned place preference was obtained with the two diets at 8 and 16 mg/kg morphine, but the lower dose of 4 mg/kg induced a place preference in control but not in (n-3) deficient mice. Taken together, these results suggest that a nutritional (n-3) PUFA deficiency can alter the responsiveness to appetitive events.