Techniques for fast noninvasive control of neuronal excitability will be of major importance for analyzing and understanding neuronal networks and animal behavior. To develop these tools we demonstrated that two light-activated signaling proteins, vertebrate rat rhodopsin 4 (RO4) and the green algae channelrhodospin 2 (ChR2), could be used to control neuronal excitability and modulate synaptic transmission. Vertebrate rhodopsin couples to the Gi͞o, pertussis toxin-sensitive pathway to allow modulation of G protein-gated inward rectifying potassium channels and voltagegated Ca 2؉ channels. Light-mediated activation of RO4 in cultured hippocampal neurons reduces neuronal firing within ms by hyperpolarization of the somato-dendritic membrane and when activated at presynaptic sites modulates synaptic transmission and paired-pulse facilitation. In contrast, somato-dendritic activation of ChR2 depolarizes neurons sufficiently to induce immediate action potentials, which precisely follow the ChR2 activation up to light stimulation frequencies of 20 Hz. To demonstrate that these constructs are useful for regulating network behavior in intact organisms, embryonic chick spinal cords were electroporated with either construct, allowing the frequency of episodes of spontaneous bursting activity, known to be important for motor circuit formation, to be precisely controlled. Thus light-activated vertebrate RO4 and green algae ChR2 allow the antagonistic control of neuronal function within ms to s in a precise, reversible, and noninvasive manner in cultured neurons and intact vertebrate spinal cords.A major challenge in understanding the relationship between neural activity and development and between neuronal circuit activity and specific behaviors is to be able to control the activity of large populations of neurons or regions of individual nerve cells simultaneously. Recently, it was demonstrated that neuronal circuits can be manipulated by expressing mutated ion channels or G protein-coupled receptors (GPCRs). For example, the regional expression of a genetically modified K ϩ channel in Drosophila was able to reduce the excitability of targeted cells (i.e., muscle, neurons, photoreceptors) (1). Silencing of cortical neurons was achieved by binding of the peptide allostatin to its exogenously expressed receptor (2). Recently, Zemelman et al. (3) elegantly demonstrated that light activation of the protein complex, encoded by the Drosophila photoreceptor genes (i.e., arrestin-2, rhodopsin, and G protein ␣ subunit), could induce action potential firing of hippocampal neurons. Activation and deactivation of neuronal firing could also be achieved when ligand-gated ion channels, such as the capsaicin receptor, menthol receptor, purinergic receptors, or lightcontrollable K ϩ channel blockers, were used to control firing in hippocampal neurons (4, 5). However, the application of these techniques to control neuronal function especially in neural circuits and living animals is limited by their relatively slow time course, the complex...

IMPORTANCE Controlled studies have shown short-term efficacy of esketamine for treatment-resistant depression (TRD), but long-term effects remain to be established. OBJECTIVE To assess the efficacy of esketamine nasal spray plus an oral antidepressant compared with an oral antidepressant plus placebo nasal spray in delaying relapse of depressive symptoms in patients with TRD in stable remission after an induction and optimization course of esketamine nasal spray plus an oral antidepressant. DESIGN, SETTING, AND PARTICIPANTS In this phase 3, multicenter, double-blind, randomized withdrawal study conducted from October 6, 2015, to February 15, 2018, at outpatient referral centers, 705 adults with prospectively confirmed TRD were enrolled; 455 entered the optimization phase and were treated with esketamine nasal spray (56 or 84 mg) plus an oral antidepressant. After 16 weeks of esketamine treatment, 297 who achieved stable remission or stable response entered the randomized withdrawal phase. INTERVENTIONS Patients who achieved stable remission and those who achieved stable response (without remission) were randomized 1:1 to continue esketamine nasal spray or discontinue esketamine treatment and switch to placebo nasal spray, with oral antidepressant treatment continued in each group. MAIN OUTCOMES AND MEASURES Time to relapse was examined in patients who achieved stable remission, as assessed using a weighted combination log-rank test. RESULTS Among the 297 adults (mean age [SD], 46.3 [11.13] years; 197 [66.3%] female) who entered the randomized maintenance phase, 176 achieved stable remission; 24 (26.7%) in the esketamine and antidepressant group and 39 (45.3%) in the antidepressant and placebo group experienced relapse (log-rank P = .003, number needed to treat [NNT], 6). Among the 121 who achieved stable response, 16 (25.8%) in the esketamine and antidepressant group and 34 (57.6%) in the antidepressant and placebo group experienced relapse (log-rank P < .001, NNT, 4). Esketamine and antidepressant treatment decreased the risk of relapse by 51% (hazard ratio [HR], 0.49; 95% CI, 0.29-0.84) among patients who achieved stable remission and 70% (HR, 0.30; 95% CI, 0.16-0.55) among those who achieved stable response compared with antidepressant and placebo treatment. The most common adverse events reported for esketamine-treated patients after randomization weretransientdysgeusia,vertigo,dissociation,somnolence,anddizziness(incidence,20.4%-27.0%), each reported in fewer patients (<7%) treated with an antidepressant and placebo. CONCLUSIONS AND RELEVANCE For patients with TRD who experienced remission or response after esketamine treatment, continuation of esketamine nasal spray in addition to oral antidepressant treatment resulted in clinically meaningful superiority in delaying relapse compared with antidepressant plus placebo.

Lentiviruses can infect non-dividing cells, and various cellular transport proteins provide crucial functions for lentiviral nuclear entry and integration. We previously showed that the viral capsid (CA) protein mediated the dependency on cellular nucleoporin (NUP) 153 during HIV-1 infection, and now demonstrate a direct interaction between the CA N-terminal domain and the phenylalanine-glycine (FG)-repeat enriched NUP153 C-terminal domain (NUP153C). NUP153C fused to the effector domains of the rhesus Trim5α restriction factor (Trim-NUP153C) potently restricted HIV-1, providing an intracellular readout for the NUP153C-CA interaction during retroviral infection. Primate lentiviruses and equine infectious anemia virus (EIAV) bound NUP153C under these conditions, results that correlated with direct binding between purified proteins in vitro. These binding phenotypes moreover correlated with the requirement for endogenous NUP153 protein during virus infection. Mutagenesis experiments concordantly identified NUP153C and CA residues important for binding and lentiviral infectivity. Different FG motifs within NUP153C mediated binding to HIV-1 versus EIAV capsids. HIV-1 CA binding mapped to residues that line the common alpha helix 3/4 hydrophobic pocket that also mediates binding to the small molecule PF-3450074 (PF74) inhibitor and cleavage and polyadenylation specific factor 6 (CPSF6) protein, with Asn57 (Asp58 in EIAV) playing a particularly important role. PF74 and CPSF6 accordingly each competed with NUP153C for binding to the HIV-1 CA pocket, and significantly higher concentrations of PF74 were needed to inhibit HIV-1 infection in the face of Trim-NUP153C expression or NUP153 knockdown. Correlation between CA mutant viral cell cycle and NUP153 dependencies moreover indicates that the NUP153C-CA interaction underlies the ability of HIV-1 to infect non-dividing cells. Our results highlight similar mechanisms of binding for disparate host factors to the same region of HIV-1 CA during viral ingress. We conclude that a subset of lentiviral CA proteins directly engage FG-motifs present on NUP153 to affect viral nuclear import.

The ability of copper to catalyze the electrochemical reduction of CO 2 has been shown to greatly depend on its nanoscale surface morphology. While previous studies found evidence of irreversible changes of copper nanoparticle and thin film electrodes following electrolysis, we present here the first observation of the reversible reconstruction of electrocatalytic copper surfaces induced by the adsorbed CO intermediate. Using attenuated total internal reflection infrared and surface-enhanced Raman spectroscopies, the reversible formation of nanoscale metal clusters on the electrode is revealed by the appearance of a new CO absorption band characteristic of CO bound to undercoordinated copper atoms and by the strong enhancement of the surface-enhanced Raman effect. Our study shows that the morphology of the catalytic copper surface is not static but dynamically adapts with changing reaction conditions.