Mutations in the Leucine Rich Repeat Kinase 2 (LRRK2) gene, first described in 2004 have now emerged as the most important genetic finding in both autosomal dominant and sporadic Parkinson's Disease (PD). While a formidable research effort has ensued since the initial gene discovery, little is known of either the normal or the pathological role of LRRK2. We have created lines of mice that express human mutant wild-type (hWT) or G2019S Lrrk2 via bacterial artificial chromosome (BAC) transgenesis. In vivo analysis of the dopaminergic system revealed abnormal dopamine neurotransmission in both hWT and G2019S transgenic mice evidenced by a decrease in extracellular dopamine levels, which was detected without pharmacological manipulation. Immunopathological analysis revealed changes in localization and increased phosphorylation of microtubule binding protein tau in G2019S mice. Quantitative biochemical analysis confirmed the presence of differential phospho-tau species in G2019S mice but surprisingly, upon dephosphorylation the tau isoform banding pattern in G2019S mice remained altered. This suggests that other post-translational modifications of tau occur in G2019S mice. We hypothesize that Lrrk2 may impact on tau processing which subsequently leads to increased phosphorylation. Our models will be useful for further understanding of the mechanistic actions of LRRK2 and future therapeutic screening.

Summary Background Childhood obesity is a major public health concern with limited treatment options. Objective The aim of this study was to assess safety, tolerability, pharmacokinetics, and pharmacodynamics during short‐term treatment with liraglutide in children (7‐11 y) with obesity. Methods In this randomized, double‐blind, placebo‐controlled trial, 24 children received at least one dose of once‐daily subcutaneous liraglutide (n = 16) or placebo (n = 8) starting at 0.3 mg with weekly dose escalations up to 3.0 mg or maximum tolerated dose, and 20 children completed the trial (14 in the liraglutide group and six in the placebo group). The primary endpoint was the number of adverse events. Results Baseline characteristics (mean ± standard deviation) included the following: age 9.9 ± 1.1 years, weight 71.5 ± 15.4 kg, and 62.5% male. Thirty‐seven adverse events were reported in nine liraglutide‐treated participants (56.3%) versus 12 events in five placebo‐treated participants (62.5%). Most adverse events were mild in severity, three were of moderate severity, and none were severe. Gastrointestinal disorders were the most frequently reported events occurring in 37.5% of liraglutide‐treated participants compared with placebo (12.5%). Six asymptomatic hypoglycaemic episodes occurred in five participants of whom four were liraglutide treated. Liraglutide exposure was consistent with dose proportionality. Body weight was the only covariate to significantly impact exposure. A significant reduction in body mass index (BMI) Z score from baseline to end of treatment (estimated treatment difference: −0.28; P = 0.0062) was observed. Conclusion Short‐term treatment with liraglutide in children with obesity revealed a safety and tolerability profile similar to trials in adults and adolescents with obesity, with no new safety issues.

J. Neurochem. (2010) 115, 209–219. Abstract Hypoxia‐inducible factor (HIF) controls the expression of genes that adapts the cellular condition to accommodate oxidative stress. The potential beneficial effect of HIF up‐regulation in ischemia has recently gained interest substantiated by the known HIF‐regulation of erythropoietin and other hypoxia accommodating genes. So far the perspectives for HIF up‐regulation has been focused on anemia and ischemia related diseases but little information is available about the relevance of HIF biology for neurodegenerative disease like Parkinson’s disease. We therefore sought out to characterize the effect of HIF‐up‐regulation on survival and dopamine homeostasis in dopaminergic cells. We used a low molecular weight HIF prolyl hydroxylase (HPH) inhibitor and lentiviral based shRNA knockdown of HPH subtypes as molecular tools to increase HIF protein level and downstream HIF‐regulated genes. We show that HIF induction results in protection against oxidative stress in cellular models based on PC12 cells and LUHMES cells. In addition, HPH inhibition elevates tyrosine hydroxylase expression and activity, which causes increased dopamine synthesis and release in both PC12 cells and a primary rat ventral mesencephalic cell culture. All together these findings suggest that prolyl hydroxylases may represent novel targets for therapeutic intervention in disorders characterized by dopamine homeostasis dysregulation like Parkinson’s disease.

The efficacies of selective 5-HT(2A) and 5-HT(6) receptor antagonists suggest potential mechanisms mediating the effects of sertindole, which has high affinity for these 5-HT receptor subtypes. The sertindole-induced improvement in cognitive function in this animal model suggests relevance for the management of cognitive deficit symptoms in schizophrenia.

The in-vitro potency and selectivity, in-vivo binding affinity and effect of the 5-HT(6)R antagonist Lu AE58054 ([2-(6-fluoro-1H-indol-3-yl)-ethyl]-[3-(2,2,3,3-tetrafluoropropoxy)-benzyl]-amine) on impaired cognition were evaluated. Lu AE58054 displayed high affinity to the human 5-HT(6) receptor (5-HT(6)R) with a Ki of 0.83 nm. In a 5-HT(6) GTPgammaS efficacy assay Lu AE58054 showed no agonist activity, but demonstrated potent inhibition of 5-HT-mediated activation. Besides medium affinity to adrenergic alpha(1A)- and alpha(1B)-adrenoreceptors, Lu AE58054 demonstrated >50-fold selectivity for more than 70 targets examined. Orally administered Lu AE58054 potently inhibited striatal in-vivo binding of the 5-HT(6) antagonist radioligand [(3)H]Lu AE60157 ([(3)H]8-(4-methylpiperazin-1-yl)-3-phenylsulfonylquinoline), with an ED(50) of 2.7 mg/kg. Steady-state modelling of an acute pharmacokinetic/5-HT(6)R occupancy time-course experiment indicated a plasma EC(50) value of 20 ng/ml. Administration of Lu AE58054 in a dose range (5-20 mg/kg p.o.) leading to above 65% striatal 5-HT(6)R binding occupancy in vivo, reversed cognitive impairment in a rat novel object recognition task induced after subchronic treatment for 7 d with phencyclidine (PCP 2 mg/kg b.i.d., i.p. for 7 d, followed by 7 d drug free). The results indicate that Lu AE58054 is a selective antagonist of 5-HT(6)Rs with good oral bioavailability and robust efficacy in a rat model of cognitive impairment in schizophrenia. Lu AE58054 may be useful for the pharmacotherapy of cognitive dysfunction in disease states such as schizophrenia and Alzheimer's disease.