The rockefeller university

Immune checkpoint blockade of the programmed cell death protein 1 (PD-1) pathway by monoclonal antibodies (Abs) has shown promising clinical benefit in the treatment of multiple cancer types. We elucidated the contribution of the fragment crystallizable (Fc) domains of anti-PD-1 and anti-PD-ligand 1 (L1) Abs for their optimal anti-tumor activity. We revealed that distinct Fey receptor (Fc gamma Rs) dependency and mechanisms account for the in vivo activity of anti-PD-1 versus anti-PD-L1 Abs. Anti-PD-1 Abs were found to be Fc gamma R independent in vivo; the presence of Fc gamma R-binding capacity compromises their anti-tumor activity. In contrast, the anti-PD-L1 Abs show augmented anti-tumor activity when activating Fc gamma R binding is introduced into the molecules, altering myeloid subsets within the tumor microenvironment.

It is widely accepted that the kinetochore is built on CENP-A-marked centromeric chromatin in a hierarchical order from inner to outer kinetochore. Recruitment of many kinetochore proteins depends on microtubule attachment status, but it remains unclear how their assembly/disassembly is orchestrated. Applying 3D structured illumination microscopy to Xenopus laevis egg extracts, here we reveal that in the absence of microtubule attachment, proteins responsible for lateral attachment and spindle checkpoint signaling expand to form micrometer-scale fibrous structures over CENP-A-free chromatin, whereas a core module responsible for end-on attachment (CENP-A, CENP-T, and Ndc80) does not. Both outer kinetochore proteins (Bub1, BubR1, Mad1, and CENP-E) and the inner kinetochore component CENP-C are integral components of the expandable module, whose assembly depends on multiple mitotic kinases (Aurora B, Mps1, and Plx1) and is suppressed by protein phosphatase 1. We propose that phospho-dependent coexpansion of CENP-C and outer kinetochore proteins promotes checkpoint signal amplification and lateral attachment, whereas their selective disassembly enables the transition to end-on attachment.

Progress has been made over the last decade in our understanding of the brain areas and circuits involved in nicotine reward and withdrawal, leading to models of addiction that assign different addictive behaviors to distinct, yet overlapping, neural circuits (Koob and Volkow, 2010; Lobo and Nestler, 2011; Tuesta et al., 2011; Volkow et al., 2011). Recently the habenulo-interpeduncular (Hb-IPN) midbrain pathway has re-emerged as a new critical crossroad that influences the brain response to nicotine. This brain area is particularly enriched in nicotinic acetylcholine receptor (nAChR) subunits alpha 5, alpha 3 and beta 4 encoded by the CHRNA5-A3-B4 gene cluster, which has been associated with vulnerability to tobacco dependence in human genetics studies. This finding, together with studies in mice involving deletion and replacement of nAChR subunits, and investigations of the circuitry, cell types and electrophysiological properties, have begun to identify the molecular mechanisms that take place in the MHb-IPN which underlie critical aspects of nicotine dependence. In the current review we describe the anatomical and functional connections of the MHb-IPN system, as well as the contribution of specific nAChRs subtypes in nicotine-mediated behaviors. Finally, we discuss the specific electrophysiological properties of MHb-IPN neuronal populations and how nicotine exposure alters their cellular physiology, highlighting the unique role of the MHb-IPN in the context of nicotine aversion and withdrawal. This article is part of the Special Issue entitled 'The Nicotinic Acetylcholine Receptor: From Molecular Biology to Cognition'. (C) 2014 Elsevier Ltd. All rights reserved.

The Bose-Einstein condensation of bound pairs made of oppositely charged fermions in a magnetic field is investigated. We find that the condensation temperature shows the magnetic catalysis effect in weak coupling and the inverse magnetic catalysis effect in strong coupling. The different responses to the magnetic field can be attributed to the competition between the dimensional reduction by Landau orbitals in pairing dynamics and the anisotropy of the kinetic spectrum of fluctuations (bound pairs in the normal phase).

Major depressive disorder (MDD) is a prevalent illness that can be precipitated by acute or chronic stress. Studies of patients with Wolfram syndrome and carriers have identified Wfs1 mutations as causative for MDD. The medial prefrontal cortex (mPFC) is known to be involved in depression and behavioral resilience, although the cell types and circuits in the mPFC that moderate depressive behaviors in response to stress have not been determined. Here, we report that deletion of Wfs1 from layer 2/3 pyramidal cells impairs the ability of the mPFC to suppress stress-induced depressive behaviors, and results in hyperactivation of the hypothalamic-pituitary-adrenal axis and altered accumulation of important growth and neurotrophic factors. Our data identify superficial layer 2/3 pyramidal cells as critical for moderation of stress in the context of depressive behaviors and suggest that dysfunction in these cells may contribute to the clinical relationship between stress and depression.

Fragile X Mental Retardation Protein (FMRP) is a regulatory RNA binding protein that plays a central role in the development of several human disorders including Fragile X Syndrome (FXS) and autism. FMRP uses an arginine-glycine-rich (RGG) motif for specific interactions with guanine (G)-quadruplexes, mRNA elements implicated in the disease-associated regulation of specific mRNAs. Here we report the 2.8-angstrom crystal structure of the complex between the human FMRP RGG peptide bound to the in vitro selected G-rich RNA. In this model system, the RNA adopts an intramolecular K+-stabilized G-quadruplex structure composed of three G-quartets and a mixed tetrad connected to an RNA duplex. The RGG peptide specifically binds to the duplex-quadruplex junction, the mixed tetrad, and the duplex region of the RNA through shape complementarity, cation-p interactions, and multiple hydrogen bonds. Many of these interactions critically depend on a type I beta-turn, a secondary structure element whose formation was not previously recognized in the RGG motif of FMRP. RNA mutagenesis and footprinting experiments indicate that interactions of the peptide with the duplex-quadruplex junction and the duplex of RNA are equally important for affinity and specificity of the RGG-RNA complex formation. These results suggest that specific binding of cellular RNAs by FMRP may involve hydrogen bonding with RNA duplexes and that RNA duplex recognition can be a characteristic RNA binding feature for RGG motifs in other proteins.

Changes in DNA methylation are required for the formation of germinal centers (GCs), but the mechanisms of such changes are poorly understood. Activation-induced cytidine deaminase (AID) has been recently implicated in DNA demethylation through its deaminase activity coupled with DNA repair. We investigated the epigenetic function of AID in vivo in germinal center B cells (GCBs) isolated from wildtype (WT) and AID-deficient (Aicda(-/-)) mice. We determined that the transit of B cells through the GC is associated with marked locus-specific loss of methylation and increased methylation diversity, both of which are lost in Aicda(-/-) animals. Differentially methylated cytosines (DMCs) between GCBs and naive B cells (NBs) are enriched in genes that are targeted for somatic hypermutation (SHM) by AID, and these genes form networks required for B cell development and proliferation. Finally, we observed significant conservation of AID-dependent epigenetic reprogramming between mouse and human B cells.

Nuclear pore complexes (NPCs) form a selective filter that allows the rapid passage of transport factors (TFs) and their cargoes across the nuclear envelope, while blocking the passage of other macromolecules. Intrinsically disordered proteins (IDPs) containing phenylalanyl-glycyl (FG)-rich repeats line the pore and interact with TFs. However, the reason that transport can be both fast and specific remains undetermined, through lack of atomic-scale information on the behavior of FGs and their interaction with TFs. We used nuclear magnetic resonance spectroscopy to address these issues. We show that FG repeats are highly dynamic IDPs, stabilized by the cellular environment. Fast transport of TFs is supported because the rapid motion of FG motifs allows them to exchange on and off TFs extremely quickly through transient interactions. Because TFs uniquely carry multiple pockets for FG repeats, only they can form the many frequent interactions needed for specific passage between FG repeats to cross the NPC.

Autosomal recessive, complete TYK2 deficiency was previously described in a patient (P1) with intracellular bacterial and viral infections and features of hyper-IgE syndrome (HIES), including atopic dermatitis, high serum IgE levels, and staphylococcal abscesses. We identified seven other TYK2-deficient patients from five families and four different ethnic groups. These patients were homozygous for one of five null mutations, different from that seen in P1. They displayed mycobacterial and/or viral infections, but no HIES. All eight TYK2-deficient patients displayed impaired but not abolished cellular responses to (a) IL-12 and IFN-alpha/beta, accounting for mycobacterial and viral infections, respectively; (b) IL-23, with normal proportions of circulating IL-17(+) T cells, accounting for their apparent lack of mucocutaneous candidiasis; and (c) IL-10, with no overt clinical consequences, including a lack of inflammatory bowel disease. Cellular responses to IL-21, IL-27, IFN-gamma, IL-28/29 (IFN-lambda), and leukemia inhibitory factor (LIF) were normal. The leukocytes and fibroblasts of all seven newly identified TYK2-deficient patients, unlike those of P1, responded normally to IL-6, possibly accounting for the lack of HIES in these patients. The expression of exogenous wild-type TYK2 or the silencing of endogenous TYK2 did not rescue IL-6 hyporesponsiveness, suggesting that this phenotype was not a consequence of the TYK2 genotype. The core clinical phenotype of TYK2 deficiency is mycobacterial and/or viral infections, caused by impaired responses to IL-12 and IFN-alpha/beta. Moreover, impaired IL-6 responses and HIES do not appear to be intrinsic features of TYK2 deficiency in humans.

Why IVF pregnancy rates decline sharply after age 43 is unknown. In this study, we compared granulosa cell (GC) function in young oocyte donors (n=31, ages 21-29), middle-aged (n=64, ages 30-37) and older infertile patients (n=41, ages 43-47). Gene expressions related to gonadotropin activity, steroidogenesis, apoptosis and luteinization were examined by real-time PCR and western blot in GCs collected from follicular fluid. FSH receptor (FSHR), aromatase (CYP19A1) and 17 beta-hydroxysteroid dehydrogenase (HSD17B) expression were found down regulated with advancing age, while LH receptor (LHCGR), P450scc (CYP11A1) and progesterone receptor (PGR) were up regulated. Upon in vitro culture, GCs were found to exhibit lower proliferation and increased apoptosis with aging. While FSH supplementation stimulated GCs growth and prevented luteinization in vitro. These observations demonstrate age-related functional declines in GCs, consistent with premature luteinization. To avoid premature luteinization in women above age 43, we advanced oocyte retrieval by administering human chorionic gonadotropin at maximal leading follicle size of 16 mm (routine 19-21 mm). Compared to normal cycles in women of similar age, earlier retrieved patients demonstrated only a marginal increase in oocyte prematurity, yet exhibited improved embryo numbers as well as quality and respectable clinical pregnancy rates. Premature follicular luteinization appears to contribute to rapidly declining IVF pregnancy chances after age 43, and can be avoided by earlier oocyte retrieval.