Correction: Mutations in LRRK2 linked to Parkinson disease sequester Rab8a to damaged lysosomes and regulate transferrin-mediated iron uptake in microglia.

[This corrects the article DOI: 10.1371/journal.pbio.3001480.].

Mutations in LRRK2 linked to Parkinson disease sequester Rab8a to damaged lysosomes and regulate transferrin-mediated iron uptake in microglia.

Mutations in leucine-rich repeat kinase 2 (LRRK2) cause autosomal dominant Parkinson disease (PD), while polymorphic LRRK2 variants are associated with sporadic PD. PD-linked mutations increase LRRK2 kinase activity and induce neurotoxicity in vitro and in vivo. The small GTPase Rab8a is a LRRK2 kinase substrate and is involved in receptor-mediated recycling and endocytic trafficking of transferrin, but the effect of PD-linked LRRK2 mutations on the function of Rab8a is poorly understood. Here, we show that gain-of-function mutations in LRRK2 induce sequestration of endogenous Rab8a to lysosomes in overexpression cell models, while pharmacological inhibition of LRRK2 kinase activity reverses this phenotype. Furthermore, we show that LRRK2 mutations drive association of endocytosed transferrin with Rab8a-positive lysosomes. LRRK2 has been nominated as an integral part of cellular responses downstream of proinflammatory signals and is activated in microglia in postmortem PD tissue. Here, we show that iPSC-derived microglia from patients carrying the most common LRRK2 mutation, G2019S, mistraffic transferrin to lysosomes proximal to the nucleus in proinflammatory conditions. Furthermore, G2019S knock-in mice show a significant increase in iron deposition in microglia following intrastriatal LPS injection compared to wild-type mice, accompanied by striatal accumulation of ferritin. Our data support a role of LRRK2 in modulating iron uptake and storage in response to proinflammatory stimuli in microglia.

Uncertainty Assessment in the Quantification of Risk Rates of Occupational Accidents.

Occupational risk rates per hour of exposure have been quantified for 63 occupational accident types for the Dutch working population. Data were obtained from the analysis of more than 9,000 accidents that occurred over a period of six years in the Netherlands and resulted in three types of reportable consequences under Dutch law: (a) fatal injury, (b) permanent injury, and (c) serious recoverable injury requiring at least one day of hospitalization. A Bayesian uncertainty assessment on the value of the risk rates has been performed. Annual risks for each of the 63 occupational accident types have been calculated, including the variability in the annual exposure of the working population to the corresponding hazards. The suitability of three risk measures-individual risk rates, individual annual risk, and number of accidents-is examined and discussed.

Comparison between lornoxicam quick-release and parecoxib for post-operative analgesia after laparoscopic cholecystectomy: A prospective randomized, placebo-controlled trial.

BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAIDs) are valuable for post-operative pain as they reduce the use of opioids. Cyclooxygenase-2 inhibitors and traditional NSAIDs can be used. This is a prospective, randomized, placebo-controlled trial to study the efficacy and the safety of the oral administration of lornoxicam quick release tablets versus intravenously administered parecoxib for the management of pain after laparoscopic cholecystectomy (LC). MATERIALS AND METHODS: One hundred and eight patients, American Society of Anesthesiologists I-II, were randomized to either group A (n = 36): Lornoxicam quick-release 8 mg PO, group B (n = 36): Parecoxib 40 mg intravenous (IV) or group C (n = 36) placebo, for post-operative analgesia, 30 min before the operation and 12 and 24 h post-operatively. All patients received a standard dose of meperidine 1 mg/kg intramuscularly before the incision and post-operatively as rescue analgesia, when visual analog scale (VAS) pain score was <4. Pain at rest and on movement was assessed at 20 min, 3, 6, 12, 18 and 24 h post-operatively. Total meperidine administration and adverse events were also recorded. RESULTS: There were significantly lower VAS pain scores at 20 min, 3, 6, 12 and 18 h at rest or with movement in the lornoxicam quick release and parecoxib groups compared with the placebo group. The number of patients requiring rescue analgesia (meperidine) was significantly higher in the placebo group (P = 0.001). The average dose of meperidine administered was significantly higher in the placebo group, both at 20 min (P = 0.013/0.007) and 24 h (P = 0.037/0.023) post-operatively. VAS scores and meperidine requirements were similar in patients who received lornoxicam or parecoxib. CONCLUSIONS: Parecoxib 40 mg IV and lornoxicam quick-release 8 mg PO every 12 h are equivalent adjuvant analgesics with a greater efficacy than placebo for post-operative analgesia in patients undergoing LC.

CDK4-E2F3 signals enhance oxidative skeletal muscle fiber numbers and function to affect myogenesis and metabolism.

Understanding how skeletal muscle fiber proportions are regulated is vital to understanding muscle function. Oxidative and glycolytic skeletal muscle fibers differ in their contractile ability, mitochondrial activity, and metabolic properties. Fiber-type proportions vary in normal physiology and disease states, although the underlying mechanisms are unclear. In human skeletal muscle, we observed that markers of oxidative fibers and mitochondria correlated positively with expression levels of PPARGC1A and CDK4 and negatively with expression levels of CDKN2A, a locus significantly associated with type 2 diabetes. Mice expressing a constitutively active Cdk4 that cannot bind its inhibitor p16INK4a, a product of the CDKN2A locus, were protected from obesity and diabetes. Their muscles exhibited increased oxidative fibers, improved mitochondrial properties, and enhanced glucose uptake. In contrast, loss of Cdk4 or skeletal muscle-specific deletion of Cdk4's target, E2F3, depleted oxidative myofibers, deteriorated mitochondrial function, and reduced exercise capacity, while increasing diabetes susceptibility. E2F3 activated the mitochondrial sensor PPARGC1A in a Cdk4-dependent manner. CDK4, E2F3, and PPARGC1A levels correlated positively with exercise and fitness and negatively with adiposity, insulin resistance, and lipid accumulation in human and rodent muscle. All together, these findings provide mechanistic insight into regulation of skeletal muscle fiber-specification that is of relevance to metabolic and muscular diseases.

A distinct hypothalamus-to-ß cell circuit modulates insulin secretion.

The central nervous system has long been thought to regulate insulin secretion, an essential process in the maintenance of blood glucose levels. However, the anatomical and functional connections between the brain and insulin-producing pancreatic ß cells remain undefined. Here, we describe a functional transneuronal circuit connecting the hypothalamus to ß cells in mice. This circuit originates from a subpopulation of oxytocin neurons in the paraventricular hypothalamic nucleus (PVNOXT), and it reaches the islets of the endocrine pancreas via the sympathetic autonomic branch to innervate ß cells. Stimulation of PVNOXT neurons rapidly suppresses insulin secretion and causes hyperglycemia. Conversely, silencing of these neurons elevates insulin levels by dysregulating neuronal signaling and secretory pathways in ß cells and induces hypoglycemia. PVNOXT neuronal activity is triggered by glucoprivation. Our findings reveal that a subset of PVNOXT neurons form functional multisynaptic circuits with ß cells in mice to regulate insulin secretion, and their function is necessary for the ß cell response to hypoglycemia.

Basal Ganglia Dysfunction Contributes to Physical Inactivity in Obesity.

Obesity is associated with physical inactivity, which exacerbates the health consequences of weight gain. However, the mechanisms that mediate this association are unknown. We hypothesized that deficits in dopamine signaling contribute to physical inactivity in obesity. To investigate this, we quantified multiple aspects of dopamine signaling in lean and obese mice. We found that D2-type receptor (D2R) binding in the striatum, but not D1-type receptor binding or dopamine levels, was reduced in obese mice. Genetically removing D2Rs from striatal medium spiny neurons was sufficient to reduce motor activity in lean mice, whereas restoring Gi signaling in these neurons increased activity in obese mice. Surprisingly, although mice with low D2Rs were less active, they were not more vulnerable to diet-induced weight gain than control mice. We conclude that deficits in striatal D2R signaling contribute to physical inactivity in obesity, but inactivity is more a consequence than a cause of obesity.

Hippocampal GSK3ß as a Molecular Link Between Obesity and Depression.

Obesity is considered as a risk factor for mood disorders including depression. Nevertheless, the mechanisms underlying this association are not clearly understood. To address this issue, we investigated the impact of high-fat (HF)-diet-induced obesity on depressive-like behavior and on serotonin (5-HT)-dependent Akt/glycogen synthase kinase 3ß (GSK3ß) signaling in the dentate gyrus (DG) of the hippocampus, which has been associated with mood regulation. We first showed that a HF diet induced significant overweight and hyperglycemia as well as a depressive-like behavior in adult Wistar rats. By using an ex vivo approach on brain slices, we demonstrated that 5-HT activates the Akt/GSK3ß cascade in the DG of control chow (C) diet-fed animals and that a 16-week HF diet feeding abolishes this activation, concurrently with a desensitization of leptin and insulin signaling in the same region. Furthermore, depressive-like behavior inversely correlated with 5-HT-induced phosphorylation of GSK3ß in the subgranular neurons of the DG. Interestingly, a substitution of HF with C diet for 6 weeks induced a total loss of depressive symptoms, whereas body weight and glycemia remained significantly higher compared to control rats. In addition, food restoration led to a recovery of the Akt/GSK3ß signaling pathway activation in the DG. In parallel, we observed a negative correlation between body weight and cell proliferation in the subgranular zone of the DG. To conclude, we provide evidence for a desensitization of 5-HT-induced Akt/GSK3ß signaling and an impaired cell proliferation in the DG by HF diet, suggesting novel molecular mechanisms linking obesity to depression.

Copper(I) complexes of 1,10-phenanthroline and heterocyclic thioamides: an experimental and theoretical (DFT) investigation of the photophysical characteristics.

A series of luminescent mixed ligand complexes of copper(I) halides with 1,10-phenanthroline and the heterocyclic thioamides pyridine-2(1H)-thione (py2SH), pyrimidine-2(1H)-thione (pymtH), 4,6-dimethylpyrimidine-2(1H)-thione (dmpymtH), 1,4,5,6-tetrahydropyrimidine-2-thione (tHpymtH), 1,3-imidazolidine-2-thione (imtH(2)) and 4,5-diphenyl-2-oxazolethiol (dpoxtH) have been synthesized and characterized. The molecular structures of two representative compounds have been established by single-crystal X-ray diffraction. The mononuclear complexes feature the metal in a distorted tetrahedral environment surrounded by the two N atoms of the chelating 1,10-phenanthroline, the thione-S atom of the thioamide, and the halogen atom. The molecular structure, the electronic and photophysical properties and the energetics of the metal-ligand interactions for [CuI(phen)(py2SH)] have been studied by means of density functional calculations.

Hypothalamic serotonin-insulin signaling cross-talk and alterations in a type 2 diabetic model.

Serotonin and insulin are key regulators of homeostatic mechanisms in the hypothalamus. However, in type 2 diabetes, the hypothalamic responsiveness to serotonin is not clearly established. We used a diabetic model, the Goto Kakizaki (GK) rats, to explore insulin receptor expression, insulin and serotonin efficiency in the hypothalamus and liver by means of Akt phosphorylation. Insulin or dexfenfluramine (stimulator of serotonin) treatment induced Akt phosphorylation in Wistar rats but not in GK rats that exhibit down-regulated insulin receptor. Studies in a neuroblastoma cell line showed that serotonin-induced Akt phosphorylation is PI3-kinase dependent. Finally, in response to food intake, hypothalamic serotonin release was reduced in GK rats, indicating impaired responsiveness of this neurotransmitter. In conclusion, hypothalamic serotonin as insulin efficiency is impaired in diabetic GK rats. The insulin-serotonin cross-talk and impairment observed is one potential key modification in the brain during the onset of diabetes.

Extracellular progranulin protects cortical neurons from toxic insults by activating survival signaling.

To reduce damage from toxic insults such as glutamate excitotoxicity and oxidative stresses, neurons may deploy an array of neuroprotective mechanisms. Recent reports show that progranulin (PGRN) gene null or missense mutations leading to inactive protein, are linked to frontotemporal lobar degeneration (FTLD), suggesting that survival of certain neuronal populations needs full expression of functional PGRN. Here we show that extracellular PGRN stimulates phosphorylation/activation of the neuronal MEK/extracellular regulated kinase (ERK)/p90 ribosomal S6 kinase (p90RSK) and phosphatidylinositol-3 kinase (PI3K)/Akt cell survival pathways and rescues cortical neurons from cell death induced by glutamate or oxidative stress. Pharmacological inhibition of MEK/ERK/p90RSK signaling blocks the PGRN-induced phosphorylation and neuroprotection against glutamate toxicity while inhibition of either MEK/ERK/p90RSK or PI3K/Akt blocks PGRN protection against neurotoxin MPP(+). Inhibition of both pathways had synergistic effects on PGRN-dependent neuroprotection against MPP(+) toxicity suggesting both pathways contribute to the neuroprotective activities of PGRN. Extracellular PGRN is remarkably stable in neuronal cultures indicating neuroprotective activities are associated with full-length protein. Together, our data show that extracellular PGRN acts as a neuroprotective factor and support the hypothesis that in FTLD reduction of functional brain PGRN results in reduced survival signaling and decreased neuronal protection against excitotoxicity and oxidative stress leading to accelerated neuronal cell death. That extracellular PGRN has neuroprotective functions against toxic insults suggests that in vitro preparations of this protein may be used therapeutically.

Multi-objective evolutionary emergency response optimization for major accidents.

Emergency response planning in case of a major accident (hazardous material event, nuclear accident) is very important for the protection of the public and workers' safety and health. In this context, several protective actions can be performed, such as, evacuation of an area; protection of the population in buildings; and use of personal protective equipment. The best solution is not unique when multiple criteria are taken into consideration (e.g. health consequences, social disruption, economic cost). This paper presents a methodology for multi-objective optimization of emergency response planning in case of a major accident. The emergency policy with regards to protective actions to be implemented is optimized. An evolutionary algorithm has been used as the optimization tool. Case studies demonstrating the methodology and its application in emergency response decision-making in case of accidents related to hazardous materials installations are presented. However, the methodology with appropriate modification is suitable for supporting decisions in assessing emergency response procedures in other cases (nuclear accidents, transportation of hazardous materials) or for land-use planning issues.

Accident sequence analysis for sites producing and storing explosives.

This paper presents a QRA-based approach for assessing and evaluating the safety of installations handling explosive substances. Comprehensive generic lists of immediate causes and initiating events of detonation and deflagration of explosive substances as well as safety measures preventing these explosions are developed. Initiating events and corresponding measures are grouped under the more general categories of explosion due to shock wave, explosion due to mechanical energy, thermal energy, electrical energy, chemical energy, and electromagnetic radiation. Generic accident sequences are developed using Event Trees. This analysis is adapted to plant-specific conditions and potentially additional protective measures are rank-ordered in terms of the induced reduction in the frequency of explosion, by including also uncertainty. This approach has been applied to 14 plants in Greece with very satisfactory results.