The Exon Junction Complex: A Multitasking Guardian of the Transcriptome.

In a recent issue of Molecular Cell, Boehm et al. (2018), Blazquez et al. (2018), and Gonatopoulos-Pournatzis et al. (2018) uncover novel mechanisms by which the cell regulates splicing of cryptic splice sites and microexons.

Mentoring during Uncertain Times.

Scientific success is mainly supported by mentoring, which often occurs through face-to-face interactions. Changes to the research environment incurred by the Coronavirus 2019 (COVID-19) pandemic have necessitated mentorship adaptations. Here, we describe how mentors can broaden their mentorship to support trainee growth and provide reassurance about trainee development amid uncertain circumstances.

Dysregulation of the chromatin environment leads to differential alternative splicing as a mechanism of disease in a human model of autism spectrum disorder.

Autism spectrum disorder (ASD) affects 1 in 44 children. Chromatin regulatory proteins are overrepresented among genes that contain high risk variants in ASD. Disruption of the chromatin environment leads to widespread dysregulation of gene expression, which is traditionally thought of as a mechanism of disease pathogenesis associated with ASD. Alternatively, alterations in chromatin dynamics could also lead to dysregulation of alternative splicing, which is understudied as a mechanism of ASD pathogenesis. The anticonvulsant valproic acid (VPA) is a well-known environmental risk factor for ASD that acts as a class I histone deacetylase inhibitor. However, the precise molecular mechanisms underlying defects in human neuronal development associated with exposure to VPA are understudied. To dissect how VPA exposure and subsequent chromatin hyperacetylation influence molecular signatures involved in ASD pathogenesis, we conducted RNA sequencing (RNA-seq) in human cortical neurons that were treated with VPA. We observed that differentially expressed genes (DEGs) were enriched for mRNA splicing, mRNA processing, histone modification and metabolism related gene sets. Furthermore, we observed widespread increases in the number and the type of alternative splicing events. Analysis of differential transcript usage (DTU) showed that exposure to VPA induces extensive alterations in transcript isoform usage across neurodevelopmentally important genes. Finally, we find that DEGs and genes that display DTU overlap with known ASD-risk genes. Altogether, these findings suggest that, in addition to differential gene expression, changes in alternative splicing correlated with alterations in the chromatin environment could act as an additional mechanism of disease in ASD.

Treatment strategies for malignant pulmonary nodule: beyond lobectomy. Point-counterpoint.

PURPOSE OF REVIEW: Technological advancement in low-dose computed tomography resulted in an increased incidental discovery of early-stage lung cancer and multifocal ground glass opacity. The demand for parenchyma-preserving treatment strategies is greater now than ever. Pulmonary ablative therapy is a groundbreaking technique to offer local ablative treatment in a lung-sparing manner. It has become a promising technique in lung cancer management with its diverse applicability. In this article, we will review the current development of ablative therapy in lung and look into the future of this innovative technique. RECENT FINDINGS: Current literature suggests that ablative therapy offers comparable local disease control to other local therapies and stereotactic body radiation therapy (SBRT), with a low risk of complications. In particular, bronchoscopic microwave ablation (BMWA) has considerably fewer pleural-based complications due to the avoidance of pleural puncture. BMWA can be considered in the multidisciplinary treatment pathway as it allows re-ablation and allows SBRT after BMWA. SUMMARY: With the benefits which ablative therapy offers and its ability to incorporate into the multidisciplinary management pathway, we foresee ablative therapy, especially BMWA gaining significance in lung cancer treatment. Future directions on developing novel automated navigation platforms and the latest form of ablative energy would further enhance clinical outcomes for our patients.

Home Therapies to Neutralize Button Battery Injury in a Porcine Esophageal Model.

STUDY OBJECTIVE: Button battery ingestion can cause alkaline esophageal injury. There is interest in first-aid household products to neutralize the injury. The objective was to investigate which household products are effective at reducing button battery injury. METHODS: Two cadaveric porcine experiments were performed. Experiment 1 utilized esophageal mucosal segments. A button battery (3VCR2032) was placed onto the mucosa, and substances (saline control, honey, jam, orange juice, yogurt, milk, and cola) were applied every 10 minutes for 6 applications. Tissue pH was measured every 10 minutes, and macroscopic ulceration size was assessed at 120 minutes. Experiment 2 used an intact esophageal model with a battery inserted into the lumen and jam, honey, and saline irrigation as per experiment 1. Tissue pH, macroscopic and histopathology changes were evaluated at 60, 90 and 120 minutes. RESULTS: In experiment 1, only honey and jam had a lower mean tissue pH at 120 minutes (8.0 [standard deviation [SD] 0.9, n=12] and 7.1 [SD 1.7, n=12], respectively) compared to saline solution 11.9 (SD 0.6, n=6, P<.0001). Both honey (0.24 cm2, SD 0.17) and jam (0.37 cm2, SD 0.40) had smaller mean areas of ulceration compared to saline solution (3.90 cm2, SD 1.03, P<.0001). In experiment 2, honey and jam had significantly lower mean tissue pH at all timepoints compared to saline solution. Histologic changes were evident at 60 minutes in the saline group, whereas honey and jam exhibited no or minimal changes until 120 minutes. CONCLUSIONS: Honey and jam were able to neutralize injury caused by a button battery resulting in a smaller area of ulceration. Jam should be further explored as a possible first-aid option as an alternative to honey in suspected button battery ingestion prior to definitive management.

Construction and preliminary validation of a tool to measure the needs of adolescents and young adults (AYA) diagnosed with cancer: the QUestionnaire nEEd Cancer AYAs: QUEEC-AYAs.

CONTEXT: In France, 2300 adolescents and young adults (AYAs, 15-25 years old) are diagnosed with cancer each year. As soon as the disease is diagnosed, a number of physical, psychological and social needs may arise. The aim of this study is to develop a tool to measure unmet needs that will allow the specificities of AYAs to be understood while allowing health care staff to mobilise the necessary actors to resolve them. METHODS: We developed the Questionnaire nEEd Cancer AYAs (QUEEC-AYAs questionnaire), from two existing questionnaires: the Cancer Needs Questionnaire Young People and the Needs Assessment & Service Bridge. A main sample of 103 AYAs then received and completed the questionnaire in order to conduct an exploratory factor analysis. RESULTS: The final structure of the QUEEC-AYAs is composed of 7 dimensions and 48 items: information (8 items), cancer care team (6 items), Physical health (4 items), Emotional health (14 items), Sexual & reproductive health (6 items), Health behaviors & wellness (4 items), Daily life (6 items). The questionnaire has a good acceptability and all domains have a Cronbach's alphas value above 0.80. CONCLUSION: The QUEEC-AYAs is the first measure of the psychosocial needs of AYAs available in French. Its systematic use in health care services should improve the coordination of care required by AYAs during and after treatment. TRIAL REGISTRATION: This study was approved by the ethics committee of the Paoli-Calmettes Institute (IRB # IPC 2021-041, 2021 May 20).

Radiation Principles, Protection, and Reporting for Interventional Pulmonology: A World Association of Bronchology and Interventional Pulmonology White Paper.

The use and availability of diverse advanced X-ray based imaging and guidance systems in the field of interventional pulmonology are rapidly growing. This popularity links inextricably to an increase in ionizing radiation use. Knowing ionizing radiation is hazardous, knowledge and competent use of X-ray imaging and guidance systems are important. The globally implemented As Low As Reasonably Achievable (ALARA) principle demands careful attention to minimize radiation exposure while achieving the precise goals of the intervention and imaging therein. To allow careful and targeted weighing of risk against reward while using X-ray based equipment, proper background knowledge of physics as well as imaging system aspects are needed. This white paper summarizes the principles of ionizing radiation which are crucial to enhance awareness and interpretation of dosimetric quantities. Consecutively, a consensus on standards for reporting radiation exposure in interventional pulmonology procedures is indicated to facilitate comparisons between different systems, approaches and results. Last but not least, it provides a list of practical measures, considerations and tips to optimize procedural imaging as well as reduce radiation dose to patients and staff.

A mouse model of Bardet-Biedl Syndrome has impaired fear memory, which is rescued by lithium treatment.

Primary cilia are microtubule-based organelles present on most cells that regulate many physiological processes, ranging from maintaining energy homeostasis to renal function. However, the role of these structures in the regulation of behavior remains unknown. To study the role of cilia in behavior, we employ mouse models of the human ciliopathy, Bardet-Biedl Syndrome (BBS). Here, we demonstrate that BBS mice have significant impairments in context fear conditioning, a form of associative learning. Moreover, we show that postnatal deletion of BBS gene function, as well as congenital deletion, specifically in the forebrain, impairs context fear conditioning. Analyses indicated that these behavioral impairments are not the result of impaired hippocampal long-term potentiation. However, our results indicate that these behavioral impairments are the result of impaired hippocampal neurogenesis. Two-week treatment with lithium chloride partially restores the proliferation of hippocampal neurons which leads to a rescue of context fear conditioning. Overall, our results identify a novel role of cilia genes in hippocampal neurogenesis and long-term context fear conditioning.

Disruption of dopamine receptor 1 localization to primary cilia impairs signaling in striatal neurons.

A rod-shaped appendage called a primary cilium projects from the soma of most central neurons in the mammalian brain. The importance of cilia within the nervous system is highlighted by the fact that human syndromes linked to primary cilia dysfunction, collectively termed ciliopathies, are associated with numerous neuropathologies, including hyperphagia-induced obesity, neuropsychiatric disorders, and learning and memory deficits. Neuronal cilia are enriched with signaling molecules, including specific G protein-coupled receptors (GPCRs) and their downstream effectors, suggesting they act as sensory organelles that respond to neuromodulators in the extracellular space. We previously showed that GPCR ciliary localization is disrupted in neurons from mouse models of the ciliopathy Bardet-Biedl syndrome (BBS). Based on this finding we hypothesized that mislocalization of ciliary GPCRs may impact receptor signaling and contribute to the BBS phenotypes. Here, we show that disrupting localization of the ciliary GPCR dopamine receptor 1 (D1) in male and female mice, either by loss of a BBS protein or loss of the cilium itself, specifically in D1-expressing neurons, results in obesity. Interestingly, the weight gain is associated with reduced locomotor activity, rather than increased food intake. Moreover, loss of a BBS protein or cilia on D1-expressing neurons leads to a reduction in D1-mediated signaling. Together, these results indicate that cilia impact D1 activity in the nervous system and underscore the importance of neuronal cilia for proper GPCR signaling.SIGNIFICANCE STATEMENT:Most mammalian neurons possess solitary appendages called primary cilia. These rod-shaped structures are enriched with signaling proteins, such as G protein-coupled receptors (GPCRs), suggesting they respond to neuromodulators. This study examines the consequences of disrupting ciliary localization of the GPCR dopamine receptor 1 (D1) in D1-expressing neurons. Remarkably, mice that have either abnormal accumulation of D1 in cilia or loss of D1 ciliary localization become obese. In both cases the obesity is associated with lower locomotor activity rather than overeating. As D1 activation increases locomotor activity, these results are consistent with a reduction in D1 signaling. Indeed, we found that D1-mediated signaling is reduced in brain slices from both mouse models. Thus, cilia impact D1 signaling in the brain.

Mutations in domain IV of elongation factor EF-G confer -1 frameshifting.

A recent crystal structure of a ribosome complex undergoing partial translocation in the absence of elongation factor EF-G showed disruption of codon-anticodon pairing and slippage of the reading frame by -1, directly implicating EF-G in preservation of the translational reading frame. Among mutations identified in a random screen for dominant-lethal mutations of EF-G were a cluster of six that map to the tip of domain IV, which has been shown to contact the codon-anticodon duplex in trapped translocation intermediates. In vitro synthesis of a full-length protein using these mutant EF-Gs revealed dramatically increased -1 frameshifting, providing new evidence for a role for domain IV of EF-G in maintaining the reading frame. These mutations also caused decreased rates of mRNA translocation and rotational movement of the head and body domains of the 30S ribosomal subunit during translocation. Our results are in general agreement with recent findings from Rodnina and coworkers based on in vitro translation of an oligopeptide using EF-Gs containing mutations at two positions in domain IV, who found an inverse correlation between the degree of frameshifting and rates of translocation. Four of our six mutations are substitutions at positions that interact with the translocating tRNA, in each case contacting the RNA backbone of the anticodon loop. We suggest that EF-G helps to preserve the translational reading frame by preventing uncoupled movement of the tRNA through these contacts; a further possibility is that these interactions may stabilize a conformation of the anticodon that favors base-pairing with its codon.