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Eye movements depend on correct patterns of connectivity between cranial motor axons and the extraocular muscles. Despite the clinical importance of the ocular motor system, little is known of the molecular mechanisms underlying its development. We have recently shown that mutations in the Chimaerin-1 gene encoding the signaling protein α2-chimaerin (α2-chn) perturb axon guidance in the ocular motor system and lead to the human eye movement disorder, Duane retraction syndrome (DRS). The axon guidance cues that lie upstream of α2-chn are unknown; here we identify candidates to be the Semaphorins (Sema) 3A and 3C, acting via the PlexinA receptors. Sema3A/C are expressed in and around the developing extraocular muscles and cause growth cone collapse of oculomotor neurons in vitro. Furthermore, RNAi knockdown of α2-chn or PlexinAs in oculomotor neurons abrogates Sema3A/C-dependent growth cone collapse. In vivo knockdown of endogenous PlexinAs or α2-chn function results in stereotypical oculomotor axon guidance defects, which are reminiscent of DRS, whereas expression of α2-chn gain-of-function constructs can rescue PlexinA loss of function. These data suggest that α2-chn mediates Sema3–PlexinA repellent signaling. We further show that α2-chn is required for oculomotor neurons to respond to CXCL12 and hepatocyte growth factor (HGF), which are growth promoting and chemoattractant during oculomotor axon guidance. α2-chn is therefore a potential integrator of different types of guidance information to orchestrate ocular motor pathfinding. DRS phenotypes can result from incorrect regulation of this signaling pathway.

Tau is a microtubule-associated protein predominantly expressed in neurons, which participates in microtubule polymerization and axonal transport. Abnormal tau metabolism leads to neurodegenerative diseases named tauopathies, such as Alzheimer’s disease and frontotemporal dementia. The alternative splicing of exon 10 (E10) in the primary transcript produces tau protein isoforms with three (3R) or four (4R) microtubule binding repeats, which are found in equal amounts in the normal adult human brain. Several tauopathies are associated with abnormal E10 alternative splicing, leading to an imbalance between 3R and 4R isoforms, which underlies disease. Correction of such imbalance represents a potential disease-modifying therapy for those tauopathies. We have previously optimized a trans -splicing RNA reprogramming strategy to modulate the 3R:4R tau content in a mouse model of tauopathy related to tau mis -splicing (htau mice), and showed that local modulation of E10 inclusion in the prefrontal cortex prevents cognitive decline, neuronal firing impairments and hyperphosphorylated tau accumulation. Furthermore, local shifting of 3R–4R tau into the striatum of htau mice prevented motor coordination deficits. However, a major bottleneck of our previous work is that local splicing regulation was performed in young mice, before the onset of pathological phenotypes. Here we tested whether regulation of tau E10 splicing could rescue tau pathology phenotypes in htau mice, after the onset of cognitive and motor impairments, comparable to early stages of human tauopathies. To determine phenotypic time course and affected brain nuclei, we assessed htau mice using behavioural tests and microPET FDG imaging over time, similarly to diagnosis methods used in patients. Based on these analyses, we performed local delivery of pre- trans splicing molecules to regulate E10 inclusion either into the medial prefrontal cortex (mPFC) or the striatum at 6-month-old once behavioral phenotypes and metabolic changes were detected. Tau isoforms modulation into the mPFC restored cognitive performance in mice that previously showed mild to severe memory impairment while motor coordination deficit was rescued after striatal injection of trans -splicing molecules. Our data suggest that tau regulation could recover pathological phenotypes early after phenotypic onset, raising promising perspectives for the use of RNA based therapies in tauopathies related to MAPT abnormal splicing.

Dopamine replacement therapy with l -DOPA is the treatment of choice for Parkinson’s disease; however, its long-term use is frequently associated with l -DOPA-induced dyskinesia (LID). Many molecules have been implicated in the development of LID, and several of these have been proposed as potential therapeutic targets. However, to date, none of these molecules have demonstrated full clinical efficacy, either because they lie downstream of dopaminergic signaling, or due to adverse side effects. Therefore, discovering new strategies to reduce LID in Parkinson’s disease remains a major challenge. Here, we have explored the tyrosine kinase Fyn, as a novel intermediate molecule in the development of LID. Fyn, a member of the Src kinase family, is located in the postsynaptic density, where it regulates phosphorylation of the NR2B subunit of the N -methyl- d -aspartate (NMDA) receptor in response to dopamine D1 receptor stimulation. We have used Fyn knockout and wild-type mice, lesioned with 6-hydroxydopamine and chronically treated with l -DOPA, to investigate the role of Fyn in the induction of LID. We found that mice lacking Fyn displayed reduced LID, ΔFosB accumulation and NR2B phosphorylation compared to wild-type control mice. Pre-administration of saracatinib (AZD0530), an inhibitor of Fyn activity, also significantly reduced LID in dyskinetic wild-type mice. These results support that Fyn has a critical role in the molecular pathways affected during the development of LID and identify Fyn as a novel potential therapeutic target for the management of dyskinesia in Parkinson’s disease.

Different risk management activities, such as land-use planning, preparedness, and emergency response, utilize scenarios of earthquake events. A systematic selection of such scenarios should aim at finding those that are representative of a certain severity, which can be measured by consequences to the exposed assets. For this reason, defining a representative scenario as the most likely one leading to a loss with a specific return period, e.g., the 100-year loss, has been proposed. We adopt this definition and develop enhanced algorithms for determining such scenarios for multiple return periods. With this approach, we identify representative earthquake scenarios for the return periods of 50, 100, 500, and 1000 years in the Chilean communes of Valparaíso and Viña del Mar, based on a synthetic earthquake catalog of 20 000 scenarios on the subduction zone with a magnitude of Mw≥5.0. We separately consider the residential-building stock and the electrical-power network and identify and compare earthquake scenarios that are representative of these systems. Because the representative earthquake scenarios are defined in terms of the annual loss exceedance rates, they vary in function of the exposed system. The identified representative scenarios for the building stock have epicenters located not further than 30 km from the two communes, with magnitudes ranging between 6.0 and 7.0. The epicenter locations of the earthquake scenarios representative of the electrical-power network are more spread out but not further than 100 km away from the two communes, with magnitudes ranging between 7.0 and 9.0. For risk management activities, we recommend considering the identified scenarios together with historical events.

Background Less invasive alternatives than early cholecystectomy (EC) for acute calculous cholecystitis (ACC) treatment have been spreading in recent years. We still lack a reliable tool to select high-risk patients who could benefit from these alternatives. Our study aimed to prospectively validate the Chole-risk score in predicting postoperative complications in patients undergoing EC for ACC compared with other preoperative risk prediction models. Method The S.P.Ri.M.A.C.C. study is a World Society of Emergency Surgery prospective multicenter observational study. From 1st September 2021 to 1st September 2022, 1253 consecutive patients admitted in 79 centers were included. The inclusion criteria were a diagnosis of ACC and to be a candidate for EC. A Cochran-Armitage test of the trend was run to determine whether a linear correlation existed between the Chole-risk score and a complicated postoperative course. To assess the accuracy of the analyzed prediction models—POSSUM Physiological Score (PS), modified Frailty Index, Charlson Comorbidity Index, American Society of Anesthesiologist score (ASA), APACHE II score, and ACC severity grade—receiver operating characteristic (ROC) curves were generated. The area under the ROC curve (AUC) was used to compare the diagnostic abilities. Results A 30-day major morbidity of 6.6% and 30-day mortality of 1.1% were found. Chole-risk was validated, but POSSUM PS was the best risk prediction model for a complicated course after EC for ACC (in-hospital mortality: AUC 0.94, p  < 0.001; 30-day mortality: AUC 0.94, p  < 0.001; in-hospital major morbidity: AUC 0.73, p  < 0.001; 30-day major morbidity: AUC 0.70, p  < 0.001). POSSUM PS with a cutoff of 25 (defined in our study as a ‘Chole-POSSUM’ score) was then validated in a separate cohort of patients. It showed a 100% sensitivity and a 100% negative predictive value for mortality and a 96–97% negative predictive value for major complications. Conclusions The Chole-risk score was externally validated, but the CHOLE-POSSUM stands as a more accurate prediction model. CHOLE-POSSUM is a reliable tool to stratify patients with ACC into a low-risk group that may represent a safe EC candidate, and a high-risk group, where new minimally invasive endoscopic techniques may find the most useful field of action. Trial Registration : ClinicalTrial.gov NCT04995380.