G2019S Mutation of Leucine-Rich Repeat Kinase 2 Is a Cause of Lewy Body Dementia in Patients With North African Ancestors.

Background: Mutations in the LRRK2 gene are the most common genetic cause of Parkinson disease but are believed to play no significant role in Lewy body disease (LBD).

Objectives: As the frequency of G2019S LRRK2 mutation is extremely high in North African patients with Parkinson disease, we postulate that the high prevalence of LBD in North Africa might be due to the same mutation because LBD and Parkinson disease share many clinical, pathological, and genetic features.

Methods: We screened patients with LBD or prodromal LBD for the G2019S mutation of LRRK2.

Glial β-oxidation regulates Drosophila energy metabolism.

The brain's impotence to utilize long-chain fatty acids as fuel, one of the dogmas in neuroscience, is surprising, since the nervous system is the tissue most energy consuming and most vulnerable to a lack of energy. Challenging this view, we here show in vivo that loss of the Drosophila carnitine palmitoyltransferase 2 (CPT2), an enzyme required for mitochondrial β-oxidation of long-chain fatty acids as substrates for energy production, results in the accumulation of triacylglyceride-filled lipid droplets in adult Drosophila brain but not in obesity. CPT2 rescue in glial cells alone is sufficient to restore triacylglyceride homeostasis, and we suggest that this is mediated by the release of ketone bodies from the rescued glial cells.

Cytokinesis remnants define first neuronal asymmetry in vivo.

Polarization of a neuron begins with the appearance of the first neurite, thus defining the ultimate growth axis. Unlike late occurring polarity events (such as axonal growth), very little is known about this fundamental process. We show here that, in Drosophila melanogaster neurons in vivo, the first membrane deformation occurred 3.

Drosophila syndecan regulates tracheal cell migration by stabilizing Robo levels.

Here we identify a new role for Syndecan (Sdc), the only transmembrane heparan sulphate proteoglycan in Drosophila, in tracheal development. Sdc is required cell autonomously for efficient directed migration and fusion of dorsal branch cells, but not for dorsal branch formation per se. The cytoplasmic domain of Sdc is dispensable, indicating that Sdc does not transduce a signal by itself.

A novel method for tissue-specific RNAi rescue in Drosophila.

Targeted gene silencing by RNA interference allows the study of gene function in plants and animals. In cell culture and small animal models, genetic screens can be performed--even tissue-specifically in Drosophila--with genome-wide RNAi libraries. However, a major problem with the use of RNAi approaches is the unavoidable false-positive error caused by off-target effects.

HMG-CoA reductase inhibition causes neurite loss by interfering with geranylgeranylpyrophosphate synthesis.

To determine whether neurite outgrowth depends upon the mevalonate pathway, we blocked mevalonate synthesis in nerve growth factor-treated PC12 cells or primary cortical neurones with atorvastatin, a 3-hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, and substituted different intermediates of the mevalonate pathway. We show that HMG-CoA reductase inhibition causes a profound reduction of neurite length, neurite loss and ultimatively cell death in undifferentiated and pre-differentiated PC12 cells and also in rat primary cortical neurones. Geranylgeranylpyrophosphate, but not farnesylpyrophosphate, squalene or cholesterol, completely compensated for the lack of mevalonate.

Syndecan 3 intramembrane proteolysis is presenilin/gamma-secretase-dependent and modulates cytosolic signaling.

The syndecans play critical roles in several signal transduction pathways. The core proteins of these heparan sulfate proteoglycans are characterized by highly conserved transmembrane and intracellular domains which are required for signaling across the membrane and for interaction with cytosolic proteins. However, regulatory mechanisms controlling these functions remain largely unknown.