Exposure to N-Ethyl-N-Nitrosourea in Adult Mice Alters Structural and Functional Integrity of Neurogenic Sites

BACKGROUND: Previous studies have shown that prenatal exposure to the mutagen N-ethyl-N-nitrosourea (ENU), a N-nitroso compound (NOC) found in the environment, disrupts developmental neurogenesis and alters memory formation. Previously, we showed that postnatal ENU treatment induced lasting deficits in proliferation of neural progenitors in the subventricular zone (SVZ), the main neurogenic region in the adult mouse brain. The present study is aimed to examine, in mice exposed to ENU, both the structural features of adult neurogenic sites, incorporating the dentate gyrus (DG), and the behavioral performance in tasks sensitive to manipulations of adult neurogenesis. METHODOLOGY/PRINCIPAL FINDINGS: 2-month old mice received 5 doses of ENU and were sacrificed 45 days after treatment. Then, an ultrastructural analysis of the SVZ and DG was performed to determine cellular composition in these regions, confirming a significant alteration. After bromodeoxyuridine injections, an S-phase exogenous marker, the immunohistochemical analysis revealed a deficit in proliferation and a decreased recruitment of newly generated cells in neurogenic areas of ENU-treated animals. Behavioral effects were also detected after ENU-exposure, observing impairment in odor discrimination task (habituation-dishabituation test) and a deficit in spatial memory (Barnes maze performance), two functions primarily related to the SVZ and the DG regions, respectively. CONCLUSIONS/SIGNIFICANCE: The results demonstrate that postnatal exposure to ENU produces severe disruption of adult neurogenesis in the SVZ and DG, as well as strong behavioral impairments. These findings highlight the potential risk of environmental NOC-exposure for the development of neural and behavioral deficits

Identification of the Rostral Migratory Stream in the Canine and Feline Brain

In the adult rodent brain, neural progenitor cells migrate from the subventricular zone of the lateral ventricle towards the olfactory bulb in a track known as the rostral migratory stream (RMS). To facilitate the study of neural progenitor cells and stem cell therapy in large animal models of CNS disease, we now report the location and characteristics of the normal canine and feline RMS. The RMS was found in Nissl-stained sagittal sections of adult canine and feline brains as a prominent, dense, continuous cellular track beginning at the base of the anterior horn of the lateral ventricle, curving around the head of the caudate nucleus and continuing laterally and ventrally to the olfactory peduncle before entering the olfactory tract and bulb. To determine if cells in the RMS were proliferating, the thymidine analog 5-bromo-2-deoxyuridine (BrdU) was administered and detected by immunostaining. BrdU-immunoreactive cells were present throughout this track. The RMS was also immunoreactive for markers of proliferating cells, progenitor cells and immature neurons (Ki-67 and doublecortin), but not for NeuN, a marker of mature neurons. Luxol fast blue and CNPase staining indicated that myelin is closely apposed to the RMS along much of its length and may provide guidance cues for the migrating cells. Identification and characterization of the RMS in canine and feline brain will facilitate studies of neural progenitor cell biology and migration in large animal models of neurologic disease

dp53 Restrains Ectopic Neural Stem Cell Formation in the Drosophila Brain in a Non-Apoptotic Mechanism Involving Archipelago and Cyclin E

Accumulating evidence suggests that tumor-initiating stem cells or cancer stem cells (CSCs) possibly originating from normal stem cells may be the root cause of certain malignancies. How stem cell homeostasis is impaired in tumor tissues is not well understood, although certain tumor suppressors have been implicated. In this study, we use the Drosophila neural stem cells (NSCs) called neuroblasts as a model to study this process. Loss-of-function of Numb, a key cell fate determinant with well-conserved mammalian counterparts, leads to the formation of ectopic neuroblasts and a tumor phenotype in the larval brain. Overexpression of the Drosophila tumor suppressor p53 (dp53) was able to suppress ectopic neuroblast formation caused by numb loss-of-function. This occurred in a non-apoptotic manner and was independent of Dacapo, the fly counterpart of the well-characterized mammalian p53 target p21 involved in cellular senescence. The observation that dp53 affected Edu incorporation into neuroblasts led us to test the hypothesis that dp53 acts through regulation of factors involved in cell cycle progression. Our results show that the inhibitory effect of dp53 on ectopic neuroblast formation was mediated largely through its regulation of Cyclin E (Cyc E). Overexpression of Cyc E was able to abrogate dp53′s ability to rescue numb loss-of-function phenotypes. Increasing Cyc E levels by attenuating Archipelago (Ago), a recently identified transcriptional target of dp53 and a negative regulator of Cyc E, had similar effects. Conversely, reducing Cyc E activity by overexpressing Ago blocked ectopic neuroblast formation in numb mutant. Our results reveal an intimate connection between cell cycle progression and NSC self-renewal vs. differentiation control, and indicate that p53-mediated regulation of ectopic NSC self-renewal through the Ago/Cyc E axis becomes particularly important when NSC homeostasis is perturbed as in numb loss-of-function condition. This has important clinical implications

Endobronchial coil treatment in severe emphysema patients with alpha-1 antitrypsin deficiency

Jeanne Marie Perotin,1 Sylvie Leroy,2 Charles Hugo Marquette,2 Hervé Mal,3 Hervé Dutau,4 Arnaud Bourdin,5 Jean Michel Vergnon,6 Christophe Pison,7 Coralie Barbe,8 Gaëtan Deslee1 On behalf of the REVOLENS Study Group 1Service de Pneumologie, INSERM U1250, Hôpital Universitaire, Reims, France; 2Service de Pneumologie, CHU de Nice, FHU OncoAge, Université Côte d’Azur, Nice, France; 3Service de Pneumologie, Hôpital Universitaire Bichat, Paris, France; 4Service d’Oncologie Thoracique, Maladies de la Plèvre, Pneumologie Interventionnelle, Hôpital Universitaire, Marseille, France; 5Département de Pneumologie et Addictologie, PhyMedExp, INSERM U1046, CNRS UMR, Hôpital Universitaire, Montpellier, France; 6Service de Pneumologie, Hôpital Universitaire, Saint Etienne, France; 7Clinique Universitaire de Pneumologie, Pôle Thorax et Vaisseaux, Inserm1055, Hôpital Universitaire Grenoble Alpes, Université Grenoble Alpes, Grenoble, France; 8Département de Méthodologie, Pôle Recherche-Innovations, Hôpital Universitaire, Reims, France Abstract: Endobronchial coil treatment (ECT) is a minimally invasive procedure developed for palliative care of patients with severe emphysema. ECT has demonstrated a decrease in hyperinflation, an improvement in quality of life, and an acceptable safety profile in randomized controlled trials (RCTs). Because alpha-1 antitrypsin deficiency (AATD) is a classical exclusion criterion in RCTs, there is no available data for ECT in AATD. In this post hoc analysis of the REVOLENS study (Réduction volumique endobronchique par spirales; ClinicalTrials.gov Identifier: NCT01822795), a multicenter 1:1 RCT which compared bilateral ECT with usual care in severe emphysema, we analyzed the efficacy and safety results at 1 year in six patients with AATD (five males, one female; mean age: 52±9 years) who underwent ECT. A significant decrease in hyperinflation (0.35 L decrease in residual volume [RV]) was observed in four out of six patients at 6 months and three out of six patients at 12 months, and an improvement in quality of life (improvement of 4 points in the St George’s Respiratory Questionnaire [SGRQ]) was observed in four out of six patients at both 6 and 12 months. Efficacy results at 6 and 12 months from the six AATD patients were compared with 84 non-AATD patients who underwent ECT, and no statistically significant differences were found for FEV1, RV, 6MWT score and SGRQ score. Respiratory-related serious adverse event was limited to pneumonia in one AATD patient at 1 year post-ECT. This post hoc study suggests that AATD patients may have similar efficacy and safety outcomes at 1 year as non-AATD patients. Because of the paucity of available data, appropriately powered studies are needed to determine the effects of ECT in AATD. Keywords: COPD, volume reduction, interventional, bronchoscop

Managing patients with chronic cough: challenges and solutions

Jeanne-Marie Perotin,1,2 Claire Launois,1 Maxime Dewolf,1 Antoine Dumazet,1 Sandra Dury,1 François Lebargy,1 Valérian Dormoy,2 Gaëtan Deslee1,2 1Department of Respiratory Diseases, University Hospital of Reims, Reims, France; 2INSERM UMRS 1250, University Hospital of Reims, Reims, France Abstract: Chronic cough is a common complaint and a frequent cause of medical consultation. Its management can be difficult. We present here an overview of the current guidelines for the management of chronic cough. Different steps are detailed, including the initial research of an obvious etiology and alert signs that should lead to further investigation of underlying condition. The diagnosis of the most frequent causes: asthma, non-asthmatic eosinophilic bronchitis, gastroesophageal reflux disease and upper airway cough syndrome should be considered, assessed and treated accordingly. Recent advances have been made in the comprehension of refractory chronic cough pathophysiology as well as its pharmacologic and non-pharmacologic treatment, especially speech pathology therapy. Keywords: asthma, gastroesophageal reflux, upper airway cough syndrome, chronic hypersensitivity syndrome, refractory chronic cough, speech pathology therap