The rockefeller university

We describe here a method to obtain functional spinal and cranial motor neurons from human induced pluripotent stem cells (iPSCs). Direct conversion into motor neuron is obtained by ectopic expression of alternative modules of transcription factors, namely Ngn2, Isl1 and Lhx3 (NIL) or Ngn2, Isl1 and Phox2a (NIP). NIL and NIP specify, respectively, spinal and cranial motor neuron identity. Our protocol starts with the generation of modified iPSC lines in which NIL or NIP are stably integrated in the genome via a piggyBac transposon vector. Expression of the transgenes is then induced by doxycycline and leads, in 5 days, to the conversion of iPSCs into MN progenitors. Subsequent maturation, for 7 days, leads to homogeneous populations of spinal or cranial MNs. Our method holds several advantages over previous protocols: it is extremely rapid and simplified; it does not require viral infection or further MN isolation; it allows generating different MN subpopulations (spinal and cranial) with a remarkable degree of maturation, as demonstrated by the ability to fire trains of action potentials. Moreover, a large number of motor neurons can be obtained without purification from mixed populations. iPSC-derived spinal and cranial motor neurons can be used for in vitro modeling of Amyotrophic Lateral Sclerosis and other neurodegenerative diseases of the motor neuron. Homogeneous motor neuron populations might represent an important resource for cell type specific drug screenings.

Axon degeneration sculpts neuronal connectivity patterns during development and is an early hallmark of several adult-onset neurodegenerative disorders. Substantial progress has been made in identifying effector mechanisms driving axon fragmentation, but less is known about the upstream signaling pathways that initiate this process. Here, we investigate the behavior of the actin-spectrin-based Membrane-associated Periodic Skeleton (MPS), and effects of actin and spectrin manipulations in sensory axon degeneration. We show that trophic deprivation (TD) of mouse sensory neurons causes a rapid disassembly of the axonal MPS, which occurs prior to protein loss and independently of caspase activation. Actin destabilization initiates TD-related retrograde signaling needed for degeneration; actin stabilization prevents MPS disassembly and retrograde signaling during TD. Depletion of beta II-spectrin, a key component of the MPS, suppresses retrograde signaling and protects axons against degeneration. These data demonstrate structural plasticity of the MPS and suggest its potential role in early steps of axon degeneration.

The Duffing oscillator is a paradigm of bistable oscillatory motion in physics, engineering, and biology. Time series of such oscillations are often observed experimentally in a nonlinear system excited by a spontaneously fluctuating force. One is then interested in estimating effective parameter values of the stochastic Duffing model from these observations-a task that has not yielded to simple means of analysis. To this end we derive theoretical formulas for the statistics of the Duffing oscillator's time series. Expanding on our analytical results, we introduce methods of statistical inference for the parameter values of the stochastic Duffing model. By applying our method to time series from stochastic simulations, we accurately reconstruct the underlying Duffing oscillator. This approach is quite straightforward-similar techniques are used with linear Langevin models-and can be applied to time series of bistable oscillations that are frequently observed in experiments.

Ants exhibit a striking diversity of reproductive systems, varying in traits such as the number of reproductives per colony [1], the mode of daughter production (sexual or asexual) [2], and the mode of caste determination (genetic or environmental) [3]. Species employing mixed reproductive systems present a unique opportunity to explore the causes and consequences of alternative breeding strategies. Mixed reproductive systems in ants include social polymorphism in colony queen number, whereby single-queen (monogyne) and multiple-queen (polygyne) colonies co-occur within species [4-7], and facultative asexuality, in which female offspring may be produced sexually or asexually within colonies [8-13 ]. Here, we document a remarkable confluence of multiple mixed reproductive systems in the tropical fire ant, Solenopsis geminate, in a population with three important features: (1) polygyne colonies produce workers sexually but queens asexually, whereas monogyne colonies produce both castes sexually; (2) polygyne queens mate with monogyne males to produce workers, but monogyne queens do not mate with polygyne males; and (3) different asexual/polygyne lineages evidently were founded separately by genetically distinct founder queens, which appear to have originated from the same neighboring monogyne population. Multiple asexual/polygyne genomes are transmitted undiluted in this system, but sterile workers produced with sperm from a sexually-reproducing/monogyne population are necessary for the persistence of these lineages. The intersection of social polymorphism, facultative asexuality, and genetic caste determination marks this population of S. geminata as an embodiment of the diversity of ant reproductive systems and suggests previously unknown connections between these phenomena.

Differences in the presence of even a few genes between otherwise identical bacterial strains may result in critical phenotypic differences. Here we systematically identify microbial genomic structural variants (SVs) and find them to be prevalent in the human gut microbiome across phyla and to replicate in different cohorts. SVs are enriched for CRISPR-associated and antibiotic-producing functions and depleted from housekeeping genes, suggesting that they have a role in microbial adaptation. We find multiple associations between SVs and host disease risk factors, many of which replicate in an independent cohort. Exploring genes that are clustered in the same SV, we uncover several possible mechanistic links between the microbiome and its host, including a region in Anaerostipes hadrus that encodes a composite inositol catabolism-butyrate biosynthesis pathway, the presence of which is associated with lower host metabolic disease risk. Overall, our results uncover a nascent layer of variability in the microbiome that is associated with microbial adaptation and host health.

Glutamate is a major excitatory neurotransmitter, and impaired glutamate clearance following synaptic release promotes spillover, inducing extra-synaptic signaling. The effects of glutamate spillover on animal behavior and its neural correlates are poorly understood. We developed a glutamate spillover model in Caenorhabditis elegans by inactivating the conserved glial glutamate transporter GLT-1. GLT-1 loss drives aberrant repetitive locomotory reversal behavior through uncontrolled oscillatory release of glutamate onto AVA, a major interneuron governing reversals. Repetitive glutamate release and reversal behavior require the glutamate receptor MGL-2/mGluR5, expressed in RIM and other interneurons presynaptic to AVA. mgl-2 loss blocks oscillations and repetitive behavior; while RIM activation is sufficient to induce repetitive reversals in glt-1 mutants. Repetitive AVA firing and reversals require EGL-30/Gaq, an mGluR5 effector. Our studies reveal that cyclic autocrine presynaptic activation drives repetitive reversals following glutamate spillover. That mammalian GLT1 and mGluR5 are implicated in pathological motor repetition suggests a common mechanism controlling repetitive behaviors.

Combination anti-retroviral therapy (ART) has revolutionized the treatment and prevention of HIV-1 infection. Taken daily, ART prevents and suppresses the infection. However, ART interruption almost invariably leads to rebound viremia in infected individuals due to a long-lived latent reservoir of integrated proviruses. Therefore, ART must be administered on a life-long basis. Here we review recent preclinical and clinical studies suggesting that immunotherapy may be an alternative or an adjuvant to ART because, in addition to preventing new infections, anti-HIV-1 antibodies clear the virus, directly kill infected cells and produce immune complexes that can enhance host immunity to the virus.

Aim: To determine if selected serotonergic and noradrenergic gene

Aim: To assess Ig20Gly tolerability in pediatric patients with primary immunodeficiencies. Patients & methods: Infusion parameters and tolerability were analyzed in pediatric patients (aged 2-5 years [n=6], 6-11 years [n=22] and 12-17 years [n=22]) receiving Ig20Gly in two Phase II/III trials. Results: Of 2624 Ig20Gly infusions, >99% did not require any rate reduction, interruption or discontinuation due to adverse events (AEs). Median maximum infusion rates and volumes/site were higher in patients 12-17 years of age (30ml/h/site; 30ml/site) versus 6-11 years (20ml/h/site; 15ml/site) and 2-5 years (18ml/h/site; 14ml/site). Rates of causally related systemic and local AEs (0.009 and 0.063 AEs/infusion) were low. Conclusion: Ig20Gly infused at relatively high rates and volumes was well tolerated in children.