The rockefeller university

The neuron specific RNA-binding proteins NOVA1 and NOVA2 are highly homologous alternative splicing regulators. NOVA proteins regulate at least 700 alternative splicing events in vivo, yet relatively little is known about the biologic consequences of NOVA action and in particular about functional differences between NOVA1 and NOVA2. Transcriptome-wide searches for isoform-specific functions, using NOVA1 and NOVA2 specific HITS-CLIP and RNA-seq data from mouse cortex lacking either NOVA isoform, reveals that NOVA2 uniquely regulates alternative splicing events of a series of axon guidance related genes during cortical development. Corresponding axonal pathfinding defects were specific to NOVA2 deficiency: Nova2-/- but not Nova1-/- mice had agenesis of the corpus callosum, and axonal outgrowth defects specific to ventral motoneuron axons and efferent innervation of the cochlea. Thus we have discovered that NOVA2 uniquely regulates alternative splicing of a coordinate set of transcripts encoding key components in cortical, brainstem and spinal axon guidance/outgrowth pathways during neural differentiation, with severe functional consequences in vivo.

Nucleocytoplasmic transport is mediated by the interaction of transport factors (TFs) with disordered phenylalanine-glycine (FG) repeats that fill the central channel of the nuclear pore complex (NPC). However, the mechanism by which TFs rapidly diffuse through multiple FG repeats without compromising NPC selectivity is not yet fully understood. In this study, we build on our recent NMR investigations showing that FG repeats are highly dynamic, flexible, and rapidly exchanging among TF interaction sites. We use unbiased long timescale all-atom simulations on the Anton supercomputer, combined with extensive enhanced sampling simulations and NMR experiments, to characterize the thermodynamic and kinetic properties of FG repeats and their interaction with a model transport factor. Both the simulations and experimental data indicate that FG repeats are highly dynamic random coils, lack intrachain interactions, and exhibit significant entropically driven resistance to spatial confinement. We show that the FG motifs reversibly slide in and out of multiple TF interaction sites, transitioning rapidly between a strongly interacting state and a weakly interacting state, rather than undergoing a much slower transition between strongly interacting and completely noninteracting (unbound) states. In the weakly interacting state, FG motifs can be more easily displaced by other competing FG motifs, providing a simple mechanism for rapid exchange of TF/FG motif contacts during transport. This slide-and-exchange mechanism highlights the direct role of the disorder within FG repeats in nucleocytoplasmic transport, and resolves the apparent conflict between the selectivity and speed of transport.

The components involved in cellular trafficking and protein recycling machinery that have been associated with increased Alzheimer's disease (AD) risk belong to the late secretory compartments for the most part. Here, we hypothesize that these late unavoidable events might be the consequence of earlier complications occurring while amyloid precursor protein (APP) is trafficking through the early secretory pathway. We investigated the relevance to AD of coat protein complex I (COPI)-dependent trafficking, an early step in Golgi-to-endoplasmic reticulum (ER) retrograde transport and one of the very first trafficking steps. Using a complex set of imaging technologies, including inverse fluorescence recovery after photobleaching (iFRAP) and photoactivatable probes, coupled to biochemical experiments, we show that COPI subunit delta (delta-COP) affects the biology of APP, including its subcellular localization and cell surface expression, its trafficking, and its metabolism. These findings demonstrate the crucial role of delta-COP in APP metabolism and, consequently, the generation of amyloid-beta (A beta) peptide, providing previously nondescribed mechanistic explanations of the underlying events.

3BNC117 is a broad and potent neutralizing antibody to HIV-1 that targets the CD4 binding site on the viral envelope spike. When administered passively, this antibody can prevent infection in animal models and suppress viremia in HIV-1-infected individuals. Here we report that HIV-1 immunotherapy with a single injection of 3BNC117 affects host antibody responses in viremic individuals. In comparison to untreated controls that showed little change in their neutralizing activity over a 6-month period, 3BNC117 infusion significantly improved neutralizing responses to heterologous tier 2 viruses in nearly all study participants. We conclude that 3BNC117-mediated immunotherapy enhances host humoral immunity to HIV-1.

Oral tolerance prevents pathological inflammatory responses to innocuous foreign antigens by peripheral regulatory T cells (pT(reg) cells). However, whether a particular subset of antigen-presenting cells (APCs) is required during dietary antigen exposure for the 'instruction' of naive CD4(+) T cells to differentiate into pT(reg) cells has not been defined. Using myeloid lineage-specific APC depletion in mice, we found that monocyte-derived APCs were dispensable, while classical dendritic cells (cDCs) were critical, for pT(reg) cell induction and oral tolerance. CD11b(-) cDCs from the gut-draining lymph nodes efficiently induced pT(reg) cells and, conversely, loss of transcription factor IRF8-dependent CD11b(-) cDCs impaired their polarization, although oral tolerance remained intact. These data reveal the hierarchy of cDC subsets in the induction of pT(reg) cells and their redundancy during the development of oral tolerance.

Background: Tofacitinib is a Janus kinase inhibitor being investigated for the treatment of moderate-to-severe plaque psoriasis. We report efficacy of tofacitinib in patient subgroups based on pooled data from two Phase 3 trials (NCT01276639, NCT01309737). Objectives: To assess consistency of treatment effects of tofacitinib versus placebo in subgroups defined by baseline characteristics, and to ascertain whether baseline characteristics are of value in optimizing tofacitinib use. Methods: Pooled data from the two trials were used to evaluate >= 75% reduction in PASI from baseline (PASI75 response) in subgroups defined by age, age at psoriasis onset, gender, race, geographical region, weight, body mass index, diabetes, metabolic syndrome, tobacco/alcohol use, psoriatic arthritis, disease activity, and prior therapy. Results: Week 16 PASI75 response rates (N=1843) were 43%, 59% and 9% with tofacitinib 5 and 10mg twice daily (BID) and placebo, respectively (each P<0.0001 versus placebo). Tofacitinib 5 and 10mg BID were effective regardless of baseline characteristics. Across subgroups, tofacitinib generally produced greater response rates with the 10 versus 5mg BID dosage. Lower absolute response rates were seen in heavier patients and patients with prior biologic experience. Conclusions: Both tofacitinib dosages demonstrated consistent efficacy versus placebo across subgroups. Lower response rates were seen in heavier patients and those with prior biologic experience. Tofacitinib 10mg BID resulted in a substantial proportion of responders regardless of baseline characteristics.

Background: beta-Amyloid (A beta) is a key pathologic element in Alzheimer's disease (AD), but the mechanisms by which it disrupts neuronal function in vivo are not completely understood. AD is characterized by a prothrombotic state, which could contribute to neuronal dysfunction by affecting cerebral blood flow and inducing inflammation. The plasma protein factor XII triggers clot formation via the intrinsic coagulation cascade, and has been implicated in thrombosis. Objectives: To investigate the potential for A beta to contribute to a prothrombotic state. Methods and results: We show that A beta activates FXII, resulting in FXI activation and thrombin generation in human plasma, thereby establishing A beta as a possible driver of prothrombotic states. We provide evidence for this process in AD by demonstrating decreased levels of FXI and its inhibitor C1 esterase inhibitor in AD patient plasma, suggesting chronic activation, inhibition and clearance of FXI in AD. Activation of the intrinsic coagulation pathway in AD is further supported by elevated fibrin levels in AD patient plasma. Conclusions: The ability of A beta to promote coagulation via the FXII-driven contact system identifies new mechanisms by which it could contribute to neuronal dysfunction and suggests potential new therapeutic targets in AD.

Background: Transforming growth factor-beta 1 (TGF-beta 1) has been implicated in the pathogenesis of aortic valve stenosis (AS). There is, however, little direct evidence for a role of active TGF-beta 1 in AS due to the sensitivity of current assays. We searched for evidence of plasma TGF-beta 1 activation by assaying Smad2/3 phosphorylation in circulating leukocytes and platelet-leukocyte aggregates (PLAs) in a mouse model of AS (Reversa). Methods: Echocardiography was used to measure AS and cardiac function. Intracellular phospho-flow cytometry in combination with optical fluorescence microscopy was used to detect PLAs and p-Smad2/3 levels. Results: Reversa mice on a western diet developed AS, had significantly increased numbers of PLAs and more intense staining for p-Smad2/3 in both PLAs and single leukocytes (all p < 0.05). p-Smad2/3 staining was more intense in PLAs than in single leukocytes in both diet groups (p < 0.05) and correlated with plasma total TGF-beta 1 levels (r = 0.38, p = 0.05 for PLAs and r = 0.37, p = 0.06 for single leukocytes) and reductions in ejection fraction (r = 0.42, p = 0.03 for PLAs and r = 037, p = 0.06 for single leukocytes). Conclusions: p-Smad2/3 staining is more intense in leukocytes of hypercholesterolemic mice that developed AS, suggesting increased circulating active TGF-beta 1 levels. Leukocyte p-Smad2/3 may be a valuable surrogate indicator of circulating active TGF-beta 1. (C) 2016 Elsevier Inc All rights reserved.