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KIF2A is an atypical kinesin that has the capacity to depolymerize microtubules. Patients carrying mutations in KIF2A suffer from progressive microcephaly and mental disabilities. While the role of this protein is well documented in neuronal migration, the relationship between its dysfunction and the pathobiology of brain disorders is unclear. Here, we report that KIF2A is dispensable for embryogenic neurogenesis but critical in postnatal stages for maturation, connectivity, and maintenance of neurons. We used a conditional approach to inactivate KIF2A in cortical progenitors, nascent postmitotic neurons, and mature neurons in mice. We show that the lack of KIF2A alters microtubule dynamics and disrupts several microtubule-dependent processes, including neuronal polarity, neuritogenesis, synaptogenesis, and axonal transport. KIF2A-deficient neurons exhibit aberrant electrophysiological characteristics, neuronal connectivity, and function, leading to their loss. The role of KIF2A is not limited to development, as fully mature neurons require KIF2A for survival. Our results emphasize an additional function of KIF2A and help explain how its mutations lead to brain disorders. ispartof: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA vol:119 issue:46 ispartof: location:United States status: published

Supplementary figures 1-3. Supplementary Figure 1: F14512 structure (A) and effects on Namalwa lymphoma cell line (B-E). Supplementary Figure 2: DNA damage induced by F14512 in Namalwa cells. Supplementary Figure 3: Illustration of decreased cell count and cell viability in tumoral lymph nodes after F14512 infusion.

Purpose: F14512 is a new topoisomerase II inhibitor containing a spermine moiety that facilitates selective uptake by tumor cells and increases topoisomerase II poisoning. F14512 is currently in a phase I/II clinical trial in patients with acute myeloid leukemia. The aim of this study was to investigate F14512 potential in a new clinical indication. Because of the many similarities between human and dog lymphomas, we sought to determine the tolerance, efficacy, pharmacokinetic/pharmacodynamic (PK/PD) relationship of F14512 in this indication, and potential biomarkers that could be translated into human trials.Experimental Design: Twenty-three dogs with stage III–IV naturally occurring lymphomas were enrolled in the phase I dose-escalation trial, which consisted of three cycles of F14512 i.v. injections. Endpoints included safety and therapeutic efficacy. Serial blood samples and tumor biopsies were obtained for PK/PD and biomarker studies.Results: Five dose levels were evaluated to determine the recommended dose. F14512 was well tolerated, with the expected dose-dependent hematologic toxicity. F14512 induced an early decrease of tumoral lymph node cells, and a high response rate of 91% (21/23) with 10 complete responses, 11 partial responses, 1 stable disease, and 1 progressive disease. Phosphorylation of histone H2AX was studied as a potential PD biomarker of F14512.Conclusions: This trial demonstrated that F14512 can be safely administered to dogs with lymphoma resulting in strong therapeutic efficacy. Additional evaluation of F14512 is needed to compare its efficacy with standards of care in dogs, and to translate biomarker and efficacy findings into clinical trials in humans. Clin Cancer Res; 21(23); 5314–23. ©2015 AACR.

Biallelic loss-of-function variants in SMPD4 cause a rare and severe neurodevelopmental disorder with progressive congenital microcephaly and early death. SMPD4 encodes a sphingomyelinase that hydrolyses sphingomyelin into ceramide at neutral pH and can thereby affect membrane lipid homeostasis. SMPD4 localizes to the membranes of the endoplasmic reticulum and nuclear envelope and interacts with nuclear pore complexes (NPC). We refine the clinical phenotype of loss-of-function SMPD4 variants by describing five individuals from three unrelated families with longitudinal data due to prolonged survival. All individuals surviving beyond infancy developed insulin-dependent diabetes, besides presenting with a severe neurodevelopmental disorder and microcephaly, making diabetes one of the most frequent age-dependent non-cerebral abnormalities. We studied the function of SMPD4 at the cellular and organ levels. Knock-down of SMPD4 in human neural stem cells causes reduced proliferation rates and prolonged mitosis. Moreover, SMPD4 depletion results in abnormal nuclear envelope breakdown and reassembly during mitosis and decreased post-mitotic NPC insertion. Fibroblasts from affected individuals show deficient SMPD4-specific neutral sphingomyelinase activity, without changing (sub)cellular lipidome fractions, which suggests a local function of SMPD4 on the nuclear envelope. In embryonic mouse brain, knockdown of Smpd4 impairs cortical progenitor proliferation and induces premature differentiation by altering the balance between neurogenic and proliferative progenitor cell divisions. We hypothesize that, in individuals with SMPD4-related disease, nuclear envelope bending, which is needed to insert NPCs in the nuclear envelope, is impaired in the absence of SMPD4 and interferes with cerebral corticogenesis and survival of pancreatic beta cells.

Isatuximab is an approved anti-CD38 monoclonal antibody with multiple antitumor modes of action. An exposure-response (E-R) analysis using data from patients with relapsed/refractory multiple myeloma (RRMM) enrolled in a phase Ib clinical study who received isatuximab at doses from 5 to 20 mg/kg weekly for 1 cycle (4 weeks) followed by every 2 weeks thereafter (qw/q2w) in combination with pomalidomide/dexamethasone (n = 44) was first used to determine the optimal dose/schedule for the phase III ICARIA-MM study. It was complemented by an E-R analysis from a second phase Ib study of patients who received isatuximab at doses from 3 to 10 mg/kg q2w or 10 or 20 mg/kg qw/q2w in combination with lenalidomide/dexamethasone (n = 52). Plasma trough concentration at week 4 (CT4W) was the best predictor for response, and the benefit of the initial 4-weekly administration was confirmed. Although the predicted overall response rate (ORR) was higher at 20 mg/kg vs. 10 mg/kg, the 95% confidence intervals were overlapping. Considering the high probability of success to reach the targeted ORR of greater than or equal to 60%, 10 mg/kg qw/q2w was selected. Results of the E-R analysis from the lenalidomide/dexamethasone study and published disease modeling using data from both phase Ib clinical studies reinforced 10 mg/kg qw/q2w as the optimal dose/schedule for the phase III ICARIA-MM study. E-R analysis showed that higher CT4W was associated with higher ORR. Developed models supported the phase III isatuximab dosing regimen selection/confirmation of 10 mg/kg qw/q2w for use in combination with pomalidomide/dexamethasone in patients with RRMM.

We report the generation and analysis of single-cell RNA-Seq data (> 38,000 cells) from mouse native retinae and induced pluripotent stem cell (iPSC)-derived retinal organoids at four matched stages of development spanning the emergence of the major retinal cell types. We combine information from temporal sampling, visualization of 3D UMAP manifolds, pseudo-time and RNA velocity analyses, to show that iPSC-derived 3D retinal organoids broadly recapitulate the native developmental trajectories. However, we observe relaxation of spatial and temporal transcriptome control, premature emergence and dominance of photoreceptor precursor cells, and susceptibility of dynamically regulated pathways and transcription factors to culture conditions in retinal organoids. We demonstrate that genes causing human retinopathies are enriched in cell-type specifying genes and identify a subset of disease-causing genes with expression profiles that are highly conserved between human retinae and murine retinal organoids. This study provides a resource to the community that will be useful to assess and further improve protocols for ex vivo recapitulation and study of retinal development.

Patients carrying autosomal dominant mutations in the histone/lysine acetyl transferases CBP or EP300 develop a neurodevelopmental disorder: Rubinstein-Taybi syndrome (RSTS). The biological pathways underlying these neurodevelopmental defects remain elusive. Here, we unravel the contribution of a stress-responsive pathway to RSTS. We characterize the structural and functional interaction between CBP/EP300 and heat-shock factor 2 (HSF2), a tuner of brain cortical development and major player in prenatal stress responses in the neocortex: CBP/EP300 acetylates HSF2, leading to the stabilization of the HSF2 protein. Consequently, RSTS patient-derived primary cells show decreased levels of HSF2 and HSF2-dependent alteration in their repertoire of molecular chaperones and stress response. Moreover, we unravel a CBP/EP300-HSF2-N-cadherin cascade that is also active in neurodevelopmental contexts, and show that its deregulation disturbs neuroepithelial integrity in 2D and 3D organoid models of cerebral development, generated from RSTS patient-derived iPSC cells, providing a molecular reading key for this complex pathology.

This analysis describes the pharmacokinetic/pharmacodynamic (PK/PD) modeling framework that supported selection of the isatuximab (anti‐CD38 monoclonal antibody) dosing regimen alongside its early clinical development in patients with relapsed/refractory multiple myeloma (RRMM). The PK/PD mathematical model characterized the variations of patient serum M‐protein concentrations, the primary marker of tumor burden in multiple myeloma (MM). Three separate PK/PD models were built sequentially as data became available from phase I clinical trials. The primary PK/PD analysis was initiated using monotherapy phase I study data (n = 122), followed by analysis of data collected from phase Ib combination studies with lenalidomide and dexamethasone (Rd, n = 40) and then with pomalidomide and dexamethasone (Pd, n = 31). Using the PK/PD model, abnormal “myeloma” protein (M‐protein) profiles under different isatuximab dosing regimens were simulated. Overall, simulations revealed that regimens which included a loading period of four weekly administrations followed by administration every 2 weeks thereafter (QW4‐Q2W), reduced M‐protein levels more than a Q2W regimen without a loading period. For isatuximab monotherapy, a 20 mg/kg dose induced greater reduction in serum M‐protein levels compared with doses equal or lower than 10 mg/kg. For isatuximab in combination with either Rd or Pd, simulations yielded no substantial benefit in terms of M‐protein reduction between isatuximab 10 mg/kg and 20 mg/kg. These PK/PD analyses supported the use of isatuximab 10 mg/kg QW4‐Q2W in combination with Pd in the phase III trial.

The six subunits (Elp1 to Elp6) Elongator complex promotes specific uridine modifications in tRNA's wobble site. Moreover, this complex has been indirectly involved in the regulation of α-tubulin acetylation in microtubules (MTs)

Macrophage polarization is a process whereby macrophages acquire distinct effector states (M1 or M2) to carry out multiple and sometimes opposite functions. We show here that translational reprogramming occurs during macrophage polarization and that this relies on the Elongator complex subunit Elp3, an enzyme that modifies the wobble uridine base U34 in cytosolic tRNAs. Elp3 expression is downregulated by classical M1-activating signals in myeloid cells, where it limits the production of pro-inflammatory cytokines via FoxO1 phosphorylation, and attenuates experimental colitis in mice. In contrast, alternative M2-activating signals upregulate Elp3 expression through a PI3K- and STAT6-dependent signaling pathway. The metabolic reprogramming linked to M2 macrophage polarization relies on Elp3 and the translation of multiple candidates, including the mitochondrial ribosome large subunit proteins Mrpl3, Mrpl13, and Mrpl47. By promoting translation of its activator Ric8b in a codon-dependent manner, Elp3 also regulates mTORC2 activation. Elp3 expression in myeloid cells further promotes Wnt-driven tumor initiation in the intestine by maintaining a pool of tumor-associated macrophages exhibiting M2 features. Collectively, our data establish a functional link between tRNA modifications, mTORC2 activation, and macrophage polarization.

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Microglia, the resident macrophages of the central nervous system, are highly motile cells that support brain development, provision neuronal signaling, and protect brain cells against damage. Proper microglial functioning requires constant cell movement and morphological changes. Interestingly, the transient receptor potential vanilloid 4 (TRPV4) channel, a calcium-permeable channel, is involved in hypoosmotic morphological changes of retinal microglia and regulates temperature-dependent movement of microglial cells both in vitro and in vivo. Despite the broad functions of TRPV4 and the recent findings stating a role for TRPV4 in microglial movement, little is known about how TRPV4 modulates cytoskeletal remodeling to promote changes of microglial motility. Here we show that acute inhibition of TRPV4, but not its constitutive absence in the Trpv4 KO cells, affects the morphology and motility of microglia in vitro. Using high-end confocal imaging techniques, we show a decrease in actin-rich filopodia and tubulin dynamics upon acute inhibition of TRPV4 in vitro. Furthermore, using acute brain slices we demonstrate that Trpv4 knockout microglia display lower ramification complexity, slower process extension speed and consequently smaller surveyed area. We conclude that TRPV4 inhibition triggers a shift in cytoskeleton remodeling of microglia influencing their migration and morphology.

In the forebrain, ventrally derived oligodendrocyte precursor cells (vOPCs) travel tangentially toward the cortex together with cortical interneurons. Here, we tested in the mouse whether these populations interact during embryogenesis while migrating. By coupling histological analysis of genetic models with live imaging, we show that although they are both attracted by the chemokine Cxcl12, vOPCs and cortical interneurons occupy mutually exclusive forebrain territories enriched in this chemokine. Moreover, first-wave vOPC depletion selectively disrupts the migration and distribution of cortical interneurons. At the cellular level, we found that by promoting unidirectional contact repulsion, first-wave vOPCs steered the migration of cortical interneurons away from the blood vessels to which they were both attracted, thereby allowing interneurons to reach their proper cortical territories.

During brain development, progenitors generate successive waves of neurons that populate distinct cerebral regions, where they settle and differentiate within layers or nuclei. While migrating and differentiating, neurons are subjected to mechanical forces arising from the extracellular matrix, and their interaction with neighboring cells. Changes in brain biomechanical properties, during its formation or aging, are converted in neural cells by mechanotransduction into intracellular signals that control key neurobiological processes. Here, we summarize recent findings that support the contribution of mechanobiology to neurodevelopment, with focus on the cerebral cortex. Also discussed are the existing toolbox and emerging technologies made available to assess and manipulate the physical properties of neurons and their environment.

Here, we summarize the current knowledge on cell diversity in the cortex and other brain regions from in vivo mouse models and in vitro models based on pluripotent stem cells. We discuss the mechanisms underlying cell proliferation and temporal progression that leads to the sequential generation of neurons dedicated to different layers of the cortex. We highlight models of corticogenesis from stem cells that recapitulate specific transcriptional and connectivity patterns from different cortical areas. We overview state-of-the art of human brain organoids modeling different brain regions, and we discuss insights into human cortical evolution from stem cells. Finally, we interrogate human brain organoid models for their competence to recapitulate the essence of human brain development.

Isatuximab, a monoclonal antibody (mAb) of immunoglobulin G (IgG) isotype, specifically targets the cluster of differentiation 38 antigen overexpressed in malignant plasma cells. Isatuximab is used to treat multiple myeloma (MM), characterized by the excessive production of abnormal "myeloma proteins" (M-proteins) that may interact with therapeutic IgG mAb on the neonatal Fc receptor (FcRn)-mediated recycling pathway. The clinical pharmacology profile of isatuximab was investigated by population pharmacokinetics (PKs) modeling in 476 patients with MM who received 1-20 mg/kg isatuximab either as single agent or in combination with pomalidomide-dexamethasone in 4 clinical trials. Isatuximab PKs were characterized by a two-compartment model with parallel time-varying linear clearance (CL) and nonlinear elimination. Due to a mechanism-based drug-disease interaction, patients secreting IgG M-protein exhibited a twofold lower drug exposure compared with patients with non-IgG MM. No dose adjustment was required based on MM immunoglobulin type because efficacy and safety profiles were comparable between IgG and non-IgG MM subpopulations. β2-microglobulin, body weight, sex, drug material, and race have a limited effect on drug exposure and do not require any dose adjustment. A typical 50% decrease in linear CL from initial treatment to steady-state was predicted, and this decrease correlated with the best overall response rate and was slower for patients with IgG MM. These findings suggest that the time-dependent effect of isatuximab is likely mediated by a combined factor of both disease state evolution and the perturbation of the FcRn-mediated recycling pathway.

A genetic change could explain increased cortical neurogenesis in modern humans

Axonal transport is used by neurons to distribute mRNAs, proteins, and organelles to their peripheral compartments in order to sustain their structural and functional integrity. Cargoes are transported along the microtubule (MT) network whose post-translational modifications influence transport dynamics. Here, we describe methods to modulate MT acetylation and record its impact on axonal transport in cultured mouse cortical projection neurons as well as in motoneurons of Drosophila melanogaster third-instar larvae. Specifically, we provide a step-by step procedure to reduce the level of MT acetylation and to record and analyze the transport of dye-labeled organelles in projection neuron axons cultured in microfluidic chambers. In addition, we describe the method to record and analyze GFP-tagged mitochondria transport along the motoneuron axons of transgenic Drosophila melanogaster third-instar larvae.

Mutations in STK11/LKB1 gene present a negative impact on tumour immune microenvironment, especially with concomitant activating KRAS mutation. These recent data may explain a decreased response to immunotherapy treatment in STK11 mutant non-small cell lung cancer (NSCLC).The primary objective is to evaluate, in a real-life setting, overall survival (OS) in patients with NSCLC according to the presence of STK11 mutation. The secondary objective is to assess time to treatment failure (TTF) for the first-line chemotherapy or immunotherapy.This observational multicentric study was conducted in Nouvelle-Aquitaine (France), for 24 months. Clinical, histopathological and imagery data were collected in each centre while the next-generation sequencing analysis was performed in Bordeaux Hospital University. Patient's data were longitudinally followed from NSCLC diagnosis date to the occurrence of censoring events (therapeutic failure or death, as applicable) or until the study end date.median OS from the first drug administration was significantly longer for STK11supwt/suppatients than STK11supmut/suppatients (16.2 months [11 - nr] versus 4.7 months [2.5-9.4]; Log-rank test P lt; 0.001). The Presence of STK11 mutation was significantly associated with shortened OS (RR = 2.26 [1.35-3.79], P = 0.002). First-line TTF was significantly shorter in STK11supmut/suppopulation and the presence of the mutation was significantly associated with an increase in treatment failures (RR = 1.87 [1.21-2.89], P = 0.005). The type of treatment (chemotherapy, immunotherapy) does not influence the amplitude of reduced TTF in patients with STK11supmut/sup.The presence of STK11 mutation is associated with poor prognosis in NSCLC.

Cerebral cortex development involves the sequential progression of biological steps driven by molecular pathways whose tight regulation often relies on ubiquitination. Ubiquitination is a posttranslational modification involved in all aspects of cellular homeostasis through the attachment of a ubiquitin (Ub) moiety on proteins. Over the past years, an increasing amount of research has highlighted the crucial role played by Ub ligases in every step of cortical development and whose impairment often leads to various neurodevelopmental disorders. In this review, we focus on the key contributions of E3 Ub ligases for the progression of the different steps of corticogenesis, as well as the pathological consequences of their mutations, often resulting in malformations of cortical development. Finally, we discuss some promising therapeutic strategies for these diseases based on recent advances in the field.

Tusamitamab ravtansine is an anti-CEACAM5 antibody-drug conjugate indicated in patients with solid tumors. Based on a previous developed semimechanistic model describing simultaneously pharmacokinetic (PK) of SAR408701, two of its active metabolites: DM4 and methyl-DM4 and naked antibody, with integration of drug-to-antibody data, the main objective of the present analysis was to evaluate covariate's impact in patients from phase I/II study (n = 254). Demographic and pathophysiologic baseline covariates were explored to explain interindividual variability on each entity PK parameter. Model parameters were estimated with good precision. Five covariates were included in the final PK model: body surface area (BSA), tumor burden, albumin, circulating target, and gender. Comparison of BSA-adjusted dosing and flat dosing supported the current BSA-based dosing regimen, to limit under and over exposure in patients with extreme BSA. Overall, this model characterized accurately the PKs of all entities and highlighted sources of PK variability. By integrating mechanistic considerations, this model aimed to improve understanding of the SAR408701 complex disposition while supporting key steps of clinical development.

Inhibitory GABAergic interneurons migrate over long distances from their extracortical origin into the developing cortex. In humans, this process is uniquely slow and prolonged, and it is unclear whether guidance cues unique to humans govern the various phases of this complex developmental process. Here, we use fused cerebral organoids to identify key roles of neurotransmitter signaling pathways in guiding the migratory behavior of human cortical interneurons. We use scRNAseq to reveal expression of GABA, glutamate, glycine, and serotonin receptors along distinct maturation trajectories across interneuron migration. We develop an image analysis software package, TrackPal, to simultaneously assess 48 parameters for entire migration tracks of individual cells. By chemical screening, we show that different modes of interneuron migration depend on distinct neurotransmitter signaling pathways, linking transcriptional maturation of interneurons with their migratory behavior. Altogether, our study provides a comprehensive quantitative analysis of human interneuron migration and its functional modulation by neurotransmitter signaling., Live‐imaging in cerebral organoids combined with single‐cell transcriptomics and small‐molecule screening reveals distinct modes of human interneuron migration and their modulation by different neurotransmitters.

In recent years, several researchers have attempted to identify COPD phenotypes using different cluster analysis. This study aimed to determine the most optimal cluster analysis (supervised vs unsupervised) to robustly identify clinical phenotypes. 2,968 COPD patients have been included from January 2014 until February 2020. General information (age, BMI, smoking, comorbidities), lung function, exacerbations and symptoms were collected. After 5 years of follow-up, vital status was recorded. A hierarchical classification on the principal components (HCPC) was performed, followed by two unsupervised classification algorithms: k-means and PAM (Partition Around Medoids). Robustness was defined according to three different indices of validation (Connectivity, Dunn and silhouette). The mean age was 70 years, 63.7% of males, current smokers: 38.7%, mean FEV1: 61.3% predicted, ≥2 exacerbations: 43.6%, mMRC dyspnea grade≥2: 56.3%, chronic cough: 58%. The 5-year mortality rate was 11.3%. Based on our hypothesis, four phenotypes were described, using the PAM method. The phenotype A (24.2%) consisted of elderly patients with severe airflow limitation, low symptoms, cardiovascular comorbidities, diabetes and a higher mortality. The phenotype B (23.9%) contained more female patients, young patients with moderate airflow limitation and a high rate of current smokers. The phenotype C (25.5%) contained patients with very severe airflow limitation, more symptoms and low BMI. The Phenotype D (26.2%) was composed of patients with mild airflow limitation and low dyspnoea. These results showed the superiority of PAM classification compared with two other algorithms (k-means and HCPC) in terms of the robustness.

Tusamitamab ravtansine (SAR408701) is an antibody-drug conjugate (ADC), combining a humanized monoclonal antibody (IgG1) targeting carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) and a potent cytotoxic maytansinoid derivative, DM4, inhibiting microtubule assembly. SAR408701 is currently in clinical development for the treatment of advanced solid tumors expressing CEACAM5. It is administered intravenously as a conjugated antibody with an average Drug Antibody Ratio (DAR) of 3.8. During SAR408701 clinical development, four entities were measured in plasma: conjugated antibody (SAR408701), naked antibody (NAB), DM4 and its methylated metabolite (MeDM4), both being active. Average DAR and proportions of individual DAR species were also assessed in a subset of patients. An integrated and semi-mechanistic population pharmacokinetic model describing the time-course of all entities in plasma and DAR measurements has been developed. All DAR moieties were assumed to share the same drug disposition parameters, excepted for clearance which differed for DAR0 (i.e. NAB entity). The conversion of higher DAR to lower DAR resulted in a DAR-dependent ADC deconjugation and was represented as an irreversible first-order process. Each conjugated antibody was assumed to contribute to DM4 formation. All data were fitted simultaneously and the model developed was successful in describing the pharmacokinetic profile of each entity. Such a structural model could be translated to other ADCs and gives insight of mechanistic processes governing ADC disposition. This framework will further be expanded to evaluate covariates impact on SAR408701 pharmacokinetics and its derivatives, and thus can help identifying sources of pharmacokinetic variability and potential efficacy and safety pharmacokinetic drivers.

The interest in therapeutic monoclonal antibodies (mAbs) has continuously growing in several diseases. However, their pharmacokinetics (PK) is complex due to their target-mediated drug disposition (TMDD) profiles which can induce a non-linear PK. This point is particularly challenging during the pre-clinical and translational development of a new mAb. This article reviews and describes the existing PK modeling approaches used to translate the mAbs PK from animal to human for intravenous (IV) and subcutaneous (SC) administration routes. Several approaches are presented, from the most empirical models to full physiologically based pharmacokinetic (PBPK) models, with a focus on the population PK methods (compartmental and minimal PBPK models). They include the translational approaches for the linear part of the PK and the TMDD mechanism of mAbs. The objective of this article is to provide an up-to-date overview and future perspectives of the translational PK approaches for mAbs during a model-informed drug development (MIDD), since the field of PK modeling has gained recently significant interest for guiding mAbs drug development.

p27(kip1) is a multifunctional protein that promotes cell cycle exit by blocking the activity of cyclin/cyclin-dependent kinase complexes as well as migration and motility via signaling pathways that converge on the actin and microtubule cytoskeleton. Despite the broad characterization of p27(kip1) function in neural cells, little is known about its relevance in microglia. Here, we studied the role of p27(kip1) in microglia using a combination of in vitro and in situ approaches. While the loss of p27(kip1) did not affect microglial density in the cerebral cortex, it altered their morphological complexity in situ. However, despite the presence of p27(kip1) in microglial processes, as shown by immunofluorescence in cultured cells, loss of p27(kip1) did not change microglial process motility and extension after applying laser-induced brain damage in cortical brain slices. Primary microglia lacking p27(kip1) showed increased phagocytic uptake of synaptosomes, while a cell cycle dead variant negatively affected phagocytosis. These findings indicate that p27(kip1) plays specific roles in microglia. J.B. is a Ph.D. student supported by the Special Research Foundation from Hasselt University and Université de Liège. Y.A.A is supported by an FWO senior postdoctoral fellowship (12H8220N), and S.K. is a Ph.D. assistant supported by Hasselt University, J.-M.R. is a full Professor at Hasselt University, B.B. is an Associate Professor at Hasselt University and L.N. is Director from the F.R.S.-F.N.R.S. This work was supported by the Special Research Foundation (BOF17DOCLI01), the FWO research grant (1521619N), Funding Hercules (I000220N), the Sint-Gillis autism research grant, ROTARY Espoir en Tête—Hoofdzaak er is Hoop, the F.R.S.-F.N.R.S. (Synet; EOS 0019118F-RG36), the Fonds Leon Fredericq (L.N.), the Fondation Médicale Reine Elisabeth (L.N.), the Fondation Simone et Pierre Clerdent (L.N), the Belgian Science Policy (IAP-VII network P7/20 (L.N.)), and the ERANET Neuron STEM-MCD and NeuroTalk (L.N.). We sincerely thank Melissa Jans and Yennick Geuens for the maintenance of the mouse colonies at BIOMED and Petra Bex and Fanny Lepiemme for providing assistance in maintaining the mouse colonies at BIOMED or the GIGA research institute. We thank Rosette Beenaerts for technical assistance with RT-PCR and Sam Duwé from the BIOMED Imaging platform for his technical support. We also thank Sandra Ormenese, Jean-Jaques Goval (deceased), and Rafaat Stephan from the GIGA-Cell imaging and flow cytometry platforms for their technical guidance

Summary Interneuron migration involves repetitive cycles of pausing and motion that include nucleokinesis and dynamic branching of the leading process. Here, we provide a step-by-step description of how to culture and record the migration of cortical interneurons. We provide two culture models: the first includes organotypic brain slices and the second medial ganglionic eminence (MGE) explants. While organotypic brain slices provide a close-to-physiological context to analyze interneuron migration into cortical streams, MGE explants are appropriate to investigate the fine details of interneuron morphology remodeling during movement. For complete details on the use and execution of this protocol, please refer to Silva et al. (2018)., Graphical abstract, Highlights • Descriptive protocols to analyze interneuron migration parameters • Detailed method to generate and maintain mouse organotypic brain slices in culture • Step-by-step procedure for in vitro electroporation of DNA plasmids in mouse brain tissues, Interneuron migration involves repetitive cycles of pausing and motion that include nucleokinesis. Here, we provide a step-by-step description of how to culture and record the migration of cortical interneurons. We provide two culture models: the first includes organotypic brain slices and the second medial ganglionic eminence (MGE) explants. While organotypic brain slices provide a close-to-physiological context to analyze interneuron migration into cortical streams, MGE explants are appropriate to investigate the fine details of interneuron morphology remodeling during movement.

The cerebral cortex is built by neural cells that migrate away from their birthplace. In the forebrain, ventrally-derived oligodendrocyte precursor cells (vOPCs) travel tangentially together with cortical interneurons (cINs) to reach the cortex. After birth, vOPCs form transient synapses with cINs before engaging later into myelination. Here we tested whether these populations interact during embryogenesis while migrating. By coupling histological analysis of mouse genetic models with live imaging, we showed that, while responding to the chemokine Cxcl12, vOPCs and cINs occupy mutually-exclusive forebrain territories. Moreover, vOPCs depletion selectively disrupts the migration and distribution of cINs. At the cellular level, we found that by promoting unidirectional contact-repulsion (UCoRe) of cINs, vOPCs steer their migration away from blood vessels and contribute to their allocation to proper migratory streams. UCoRe is thus an efficient strategy to spatially control the competition for a shared chemoattractant, thereby allowing cINs to reach proper cortical territories.

The cerebral cortex is an evolutionarily advanced brain structure that computes higher motor, sensory and cognitive functions. Its complex organization reflects the exquisite cell migration and differentiation patterns that take place during embryogenesis. Recent evidence supports an essential role for cell migration in shaping the developing cerebral cortex via direct cellular contacts and spatially organized diffusible cues that regulate the establishment of its cytoarchitecture and function. Identifying the nature of the crosstalk between cell populations at play during brain development is key to understanding how cerebral cortical morphogenesis proceeds in health and disease.

Introduction and objective Dyspnoea is a major symptom in COPD patients, but the determinants that could be associated with a higher dyspnoea mMRC score in COPD patients remain unclear. Our research aimed to study the determinants of dyspnoea at the threshold of 1, 2, 3 and 4 mMRC. Patients and methods Diagnosis of COPD was made using spirometry with post-bronchodilator FEV 1 FVC 70 % . An online questionnaire has been employed by pulmonologists to recruit COPD patients. The following variables were collected: age, gender, BMI, FEV1, RV, IC, TLC, FRC, mMRC, frequency of exacerbations and comorbidities. The LASSO was used to select the variables associated with the mMRC dyspnoea scale in a subgroup (who had no missing IC, RV and FRC values) of 421 COPD patients defined by the previously mentioned variables. Results One thousand nine hundred and sevety-three patients (65.3% males, average age = 66 ± 10, 38% current smokers) were included. Dyspnoea was correlated with a low FEV1 and with the number of exacerbations in the past 12 months. Multivariate analysis showed that the determinants of dyspnoea(mMRC ≥ 2) are: FEV1: OR = 3.71[2.86–4.82]; anxiety: OR = 2.52[1.82–3.47]; cough: OR = 1.94[1.57–2.40]; bronchiectasis: OR = 1.84[1.03–3.29]; age: OR = 1.80[1.45–2.24]; hyperinflation (RV/TLC): OR = 1.68[1.34–2.11]; ischemic cardiopathy: OR = 1.63[1.22–2.18]; hypertension: OR = 1.52[1.21–1.91]; exacerbations (≥ 2): OR = 1.41[1.10–1.81]; women: OR = 1.39[1.10–1.74] and overweight: OR = 1.33[1.06–1.67]. The subgroup analysis showed that: FEV1: OR = 3.47[1.96–6.12]; exacerbations (≥ 2) OR = 2.31[1.33–4.17] and hyperinflation (IC/TLC) OR = 0.57[0.35–0.85] were associated with higher dyspnoea (mMRC ≥ 2). Conclusion Our results showed that dyspnoea is related to the severity of airflow limitation, gender, exacerbations, comorbidities and hyperinflation.

The axonal microtubules (MTs) support long-distance transport of cargoes that are dispatched to distinct cellular subcompartments. Among them, mRNAs are directly transported in membraneless ribonucleoprotein (RNP) granules that, together with ribosomes, can also hitchhike on fast-moving membrane-bound organelles for accurate transport along MTs. These organelles serve as platforms for mRNA translation, thus generating axonal foci of newly synthesized proteins. Local translation along axons not only supports MT network integrity but also modulates the processivity and function of molecular motors to allow proper trafficking of cargoes along MTs. Thus, identifying the mechanisms that coordinate axonal transport with local protein synthesis will shed new light on the processes underlying axon development and maintenance, whose deregulation often contribute to neurological disorders.

The main factors that increase the mortality risk of COPD patients are age, comorbidities and the severity of airflow obstruction. This study aimed to validate the clinically relevant COPD phenotypes found by Burgel P-R et al [1] and analyzed their impact on 5-year mortality in the PALOMB cohort. COPD patients (post-BD FEV1/FVC 2,653 patients (66 years old, 64.27% males) were included. Application of the CART-based algorithm to Palomb cohort confirmed that it identified 5 COPD phenotypes with different clinical characteristics. In addition: The high proportion of FEV1 decline (≥100 ml/yr) belongs to phenotype 1 and 4; the majority of patients in these phenotypes were under oxygen therapy and they were associated with higher rates of exacerbation, lung cancer, anxiety and depression. These results confirmed the identification of five clinically relevant COPD phenotypes. A novel finding of this study is that FEV1 decline, frequency of exacerbations and other comorbidities were associated with the more severe phenotypes. Fundings: Bordeaux Univ Foundation, Novartis, Isis Medical, GSK, BI, Chiesi.

SummaryThe global emergence of Zika virus (ZIKV) in the last decade revealed the unprecedented ability for a mosquito-borne virus to cause congenital birth defects such as microcephaly. A puzzling aspect of ZIKV emergence is that all human outbreaks and birth defects to date have been exclusively associated with the Asian ZIKV lineage, despite a growing body of laboratory evidence pointing towards higher transmissibility and pathogenicity of the African ZIKV lineage. Whether this apparent paradox reflects the use of relatively old African ZIKV strains in most laboratory studies is unclear. Here, we experimentally compared the transmissibility and pathogenicity of seven low-passage ZIKV strains representing the recently circulating viral genetic diversity. We found that recent African ZIKV strains largely outperformed their Asian counterparts in mosquito transmission kinetics experiments, which translated into a markedly higher epidemic potential in outbreak computer simulations. In addition, African ZIKV strains were significantly more lethal than Asian ZIKV strains in immunocompromised adult mice. Finally, prenatal infection of immunocompetent mouse embryos with an African ZIKV strain resulted in embryonic death whereas it caused microcephaly with Asian ZIKV strains. Together, our results demonstrate the high epidemic potential and pathogenicity of recent ZIKV strains from Africa. Importantly, they also imply that the African ZIKV lineage could more easily go unnoticed by public health surveillance systems than the Asian ZIKV lineage due to its propensity to cause fetal loss rather than birth defects.

Microtubule (MT)-based transport is an evolutionary conserved processed finely tuned by posttranslational modifications. Among them, α-tubulin acetylation, which is catalyzed by the α-tubulin N-acetyltransferase 1, Atat1, promotes the recruitment and processivity of molecular motors along MT tracks. However, the mechanisms that controls Atat1 activity remains poorly understood. Here, we show that a pool of vesicular ATP-citrate lyase Acly acts as a rate limiting enzyme to modulate Atat1 activity by controlling availability of Acetyl-Coenzyme-A (Acetyl-CoA). In addition, we showed that Acly expression is reduced upon loss of Elongator activity, further connecting Elongator to Atat1 in the pathway regulating α-tubulin acetylation and MT-dependent transport in projection neurons, across species. Remarkably, comparable defects occur in fibroblasts from Familial Dysautonomia (FD) patients bearing an autosomal recessive mutation in the gene coding for the Elongator subunit ELP1. Our data may thus shine new light on the pathophysiological mechanisms underlying FD.Competing Interest StatementThe authors have declared no competing interest.View Full Text

Background The current prevalence of chronic obstructive pulmonary disease (COPD) in France is estimated to be 2.6 million and is predicted to increase to 2.8 million by 2025. Presently, there is a lack of data on COPD management within the private healthcare setting. The aim of this study was to investigate the management of COPD exacerbations by pulmonologists within private practices in France. Methods A prospective, online, qualitative survey was distributed to private practice pulmonologists in France. The survey covered all aspects of COPD management from diagnosis and therapeutic management, to secondary prevention and organization of care. Survey responses were collected between 27 January 2018 and 18 June 2018 and all data were summarized descriptively. Results The survey had a response rate of 20.6%, with 116 out of 563 pulmonologists providing responses. Overall, 87.4% of respondents stated that the management of COPD represented over 15% of their total clinical activity. Most respondents indicated that they work closely with general practitioners and a large multidisciplinary team to manage patients with numerous comorbidities. Following a COPD exacerbation, the majority of respondents (78.4%) were in favor of using respiratory-connected devices (class 2a-connected medical device according to the French HAS classification and available on medical prescription) to assist with patient follow-up at home. Conclusions COPD management forms part of the core clinical activity for pulmonologists within the private practice setting in France. Patients with COPD generally have multiple comorbidities and are managed by a multidisciplinary team in line with French guidelines. The use of respiratory-connected devices was highlighted as an important new strategy for improving patient care following a COPD exacerbation.

BACKGROUND Busulfan (Bu) is the cornerstone of conditioning regimens prior to hematopoietic stem cell transplantation, widely used in both adults and children for the treatment of malignant and nonmalignant diseases. Despite an intravenous formulation, interindividual variability (IIV) remains high and optimal exposure difficult to achieve, especially in neonates and infants. PROCEDURE To ensure both efficacy and safety, we set up in 2005 an observational study designed for children not fully assessed during the drug registration procedure. From a large cohort of 540 patients, we developed a Bu population pharmacokinetic model based on body weight (BW) and maturation concepts to reduce IIV and optimize exposure. A new dosing nomogram was evaluated to better fit the population pharmacokinetic model. RESULTS Bu clearance IIV was significantly decreased from 61.3% (covariate-free model) to 28.6% when combining BW and maturation function. Median Bu area under the curve (AUC) was 1179 µmol/L × min compared to 1025 with the EMA dosing nomogram for children

The cyclin-dependent kinase inhibitor p27Kip1 (p27) has been involved in promoting autophagy and survival in conditions of metabolic stress. While the signaling cascade upstream of p27 leading to its cytoplasmic localization and autophagy induction has been extensively studied, how p27 stimulates the autophagic process remains unclear. Here, we investigated the mechanism by which p27 promotes autophagy upon glucose deprivation. Mouse embryo fibroblasts (MEFs) lacking p27 exhibit a decreased autophagy flux compared to wild-type cells and this is correlated with an abnormal distribution of autophagosomes. Indeed, while autophagosomes are mainly located in the perinuclear area in wild-type cells, they are distributed throughout the cytoplasm in p27-null MEFs. Autophagosome trafficking towards the perinuclear area, where most lysosomes reside, is critical for autophagosome–lysosome fusion and cargo degradation. Vesicle trafficking is mediated by motor proteins, themselves recruited preferentially to acetylated microtubules, and autophagy flux is directly correlated to microtubule acetylation levels. p27−/− MEFs exhibit a marked reduction in microtubule acetylation levels and restoring microtubule acetylation in these cells, either by re-expressing p27 or with deacetylase inhibitors, restores perinuclear positioning of autophagosomes and autophagy flux. Finally, we find that p27 promotes microtubule acetylation by binding to and stabilizing α-tubulin acetyltransferase (ATAT1) in glucose-deprived cells. ATAT1 knockdown results in random distribution of autophagosomes in p27+/+ MEFs and impaired autophagy flux, similar to that observed in p27−/− cells. Overall, in response to glucose starvation, p27 promotes autophagy by facilitating autophagosome trafficking along microtubule tracks by maintaining elevated microtubule acetylation via an ATAT1-dependent mechanism.

Introduction Exacerbations are key events in the natural history of COPD, but our understanding of their longitudinal determinants remains unclear. We used data from a large observational study to test the hypothesis that vaccination status and comorbidities could be associated with the occurrence of exacerbations profile. Methods Diagnosed COPD patients have been included by their pulmonologists, with up to 3 years of follow-up. Data were analyzed using the KmL method designed to cluster longitudinal data and receiver operating characteristic curve analysis to determine the best threshold to allocate patients to identified clusters. Results 932 COPD patients were included since January 2014, 446 patients (65.68% males, 35.59% current smokers) were followed over a period of 3 years with complete data. 239(28.15%) patients reported two or more exacerbations in the year before enrolment (frequent exacerbations). Among them 142(16.68%) also had frequent exacerbations in the first year of the study, and 69(8.10%) who remained frequent exacerbators in the second year. Based on our hypothesis, we were able to determine four phenotypes: A (infrequent), B (frequent in underweight patients), C (transient), and D (frequent in obese patients). Frequent exacerbators had more airflow limitation and symptoms. Irrespective of cut-offs set to define the optimal number of clusters, a history of exacerbations OR: 3.72[2.53–5.49], presence of anxiety OR: 2.03[1.24–3.31] and absence of the annual influenza vaccination OR: 1.97[1.20–3.24] remained associated with the frequent exacerbator phenotypes. Conclusions The most important determinants of frequent exacerbations are a history of exacerbations, anxiety and unvaccinated against influenza.

The transcription factor Zeb2 controls fate specification and subsequent differentiation and maturation of multiple cell types in various embryonic tissues. It binds many protein partners, including activated Smad proteins and the NuRD co-repressor complex. How Zeb2 subdomains support cell differentiation in various contexts has remained elusive. Here, we have studied the role of Zeb2 and its domains in neurogenesis and neural differentiation in the young postnatal ventricular-subventricular zone (V-SVZ), where neural stem cells generate olfactory bulb-destined interneurons. Conditional Zeb2 knockouts and separate acute loss- and gain-of-function approaches indicated that Zeb2 is essential to control apoptosis and neuronal differentiation of V-SVZ progenitors before and after birth, and identified Sox6 as Zeb2-dependent and potential downstream target gene. Zeb2 genetic inactivation impaired the differentiation potential of the V-SVZ niche in a cell-autonomous fashion. We also provide evidence that its normal function in the V-SVZ involves non-autonomous mechanisms as well. Additionally, we could demonstrate distinct roles for Zeb2 protein-binding domains, suggesting that Zeb2 partners co-determine neuronal output from the mouse V-SVZ in both quantitative and qualitative manners in early postnatal life. ispartof: Development vol:147 issue:10 ispartof: location:England status: published

The formation of functional neuronal networks requires the coordinated migration of neural cells from their birthplaces to final destinations where they differentiate to acquire specific functions. The migration strategy adopted by these different cell types is critical to form and organize tissue domains, preserve topographic information, and favor specific connectivity patterns. The first observations that some neuronal cells also move in nonradial planes in the developing cortical wall, independently of radial glial processes, were made in the 1990s. These neurons were identified as interneurons originating from the ventral forebrain a few years later. Since this discovery, the cellular and molecular characterization of interneuron migration underwent a remarkable development. Tangential migration brings ventrally generated neurons to diverse structures such as the cerebral cortex, striatum, or the olfactory bulb. Some of these regions are located at significant distances from the subpallium; thus, tangential migration is the migration mode of cells that cross boundaries and integrate remarkable molecularly distinct locations. Their ability to cross boundaries overcame the challenge of bringing together cell populations initially segregated in distinct microenvironments contributing for their fate acquisition. Most of the current knowledge regarding routes, guidance, and cellular dynamics of interneuron migration comes from studies conducted in transgenic mice. Here, we present a summary of these studies and a perspective on how new technological developments can soon aid extending the knowledge we have been acquiring to physiological and pathological human models.

International audience; Background: The recent outbreak of Zika virus (ZIKV) infection and the associated increased prevalence of microcephaly in Brazil underline the impact of viral infections on embryo-fetal development. The aim of the present study is to provide a detailed clinical and histopathological study of the fetal disruption caused by the ZIKV, with a special focus on the associated neuropathological findings. Methods: A detailed feto-placental examination, as well as neuropathological and neurobiological studies were performed on three fetuses collected after pregnancy termination between 22 and 25 weeks of gestation (WG), because brain malforma-tions associated with a maternal and fetal ZIKV infection was diagnosed. Results: In all three cases, the maternal infection occurred during the first trimester of pregnancy. A small head was observed on the ultrasound examination of the second trimester of pregnancy and led to the diagnosis of ZIKV fetopathy and pregnancy termination. The fetal histopathological examination was unremarkable on the viscera but showed on the testis an interstitial lymphocytic infiltrate. The placenta contained a Hofbauer cells hyperplasia with signs of inflammation. Neu-ropathological findings included a meningoencephalitis and an ex vacuo hydrocepha-lus. Immunohistochemical studies showed the presence of T lymphocytic and histiocytic meningitis associated with an abundant cerebral astroglial and macrophagic reaction. In situ hybridization demonstrated, abundant ZIKV particles within the cerebral parenchyma mainly in the ventricular/subventricular zone and in the cortical plate. In addition massive cells death and endoplasmic reticulum damage were present. Conclusion: The present study reports on the clinical and histopathological findings observed in three fetuses infected by the ZIKV. It emphasizes the severity of brain damages and the minimal visceral and placental changes observed upon ZIKV infection. This confirms the selective neurotropism of ZIKV. Finally, it allows us to describe the cascade of multifactorial developmental defects leading to microcephaly.

Neural stem cells give rise to granule dentate neurons throughout life in the hippocampus. Upon activation, these stem cells generate fast proliferating progenitors that complete several rounds of divisions before differentiating into neurons. Although the mechanisms regulating the activation of stem cells have been intensively studied, little attention has been given so far to the intrinsic machinery allowing the expansion of the progenitor pool. The cell cycle protein Cdk6 positively regulates the proliferation of hippocampal progenitors, but the mechanism involved remains elusive. Whereas Cdk6 functions primarily as a cell cycle kinase, it can also act as transcriptional regulator in cancer cells and hematopoietic stem cells. Using mouse genetics, we show here that the function of Cdk6 in hippocampal neurogenesis relies specifically on its kinase activity. The present study also reveals a specific regulatory mechanism for Cdk6 in hippocampal progenitors. In contrast to the classical model of the cell cycle, we observe that the Cip/Kip family member p27, rather than the Ink4 family, negatively regulates Cdk6 in the adult hippocampus. Altogether, our data uncover a unique, cell type-specific regulatory mechanism controlling the expansion of hippocampal progenitors, where Cdk6 kinase activity is modulated by p27.

Aims Vinflunine is a novel tubulin-targeted inhibitor indicated as a single agent for the treatment of bladder cancers after failure of prior platinum-based therapy. Its pharmacokinetics (PK) and pharmacodynamics (PD) have been independently characterized through several phase I and phase II studies. However, no global pharmacometric analysis had been conducted as yet. Methods Vinflunine concentrations and safety data from 18 phase I and phase II studies were used to conduct population PK and PK/PD analysis, using Nonmem. A four-compartment model was used to describe vinflunine PK and several covariates were tested to explain interindividual variability. In terms of PK/PD relationship, a semiphysiological population PK/PD model was applied to describe time course of absolute neutrophil counts (ANC) after vinflunine administration and logistic regression models were used to test the relationship between vinflunine exposure and toxicities. Results Vinflunine clearance is explained by creatinine clearance, body surface area and combination with PEGylated doxorubicin, leading to a decrease from 28.2 to 25.3% of the interindividual variability. When vinflunine dose is decreased, simulations of ANC time course (via a semiphysiological model) after vinflunine administration show a risk of neutropenia grade 3–4 at cycle 2 always lower than when dose is delayed. As an example, for moderate renal impaired patients, the risk is 42.1% when vinflunine is dosed at 320 mg m–2 once every 4 weeks vs. 23.3% for 280 mg m–2 once every 3 weeks. Conclusions We propose for the first time a global comprehensive clinical pharmacological analysis for intravenous vinflunine that may help drive dose adjustment.