Search

We present a model of political networks that integrates both the choice of trade partners (the extensive margin) and trade volumes (the intensive margin). Our model predicts that regimes secure in their survival, including democracies as well as some consolidated authoritarian regimes, will trade more on the extensive margin than vulnerable autocracies, which will block trade in products that would expand interpersonal contact among their citizens. We apply a two-stage Bayesian LASSO estimator to detailed measures of institutional features and highly disaggregated product-level trade data encompassing 131 countries over a half century. Consistent with our model, we find that (a) political institutions matter for the extensive margin of trade but not for the intensive margin and (b) the effects of political institutions on the extensive margin of trade vary across products, falling most heavily on those goods that involve extensive interpersonal contact.

Dysfunction of YEATS-domain-containing MLLT1, an acetyl/acyl-lysine dependent epigenetic reader domain, has been implicated in the development of aggressive cancers. Mutations in the YEATS domain have been recently reported as a cause of MLLT1 aberrant reader function. However, structural basis for the reported alterations in affinity for acetyled/acylated histone has remained elusive. Here, we report the crystal structures of both insertion and substitution present in cancer, revealing significant conformational changes of the YEATS-domain loop 8. Structural comparison demonstrates that such alteration not only altered the binding interface for acetylated/acylated histones, but the sequence alterations in the T1 loop may enable dimeric assembly consistent inducing self-association behavior. Nevertheless, we show that also the MLLT1 mutants can be targeted by developed acetyllysine mimetic inhibitors with affinities similarly to wild type. Our report provides a structural basis for the altered behaviors and potential strategy for targeting oncogenic MLLT1 mutants.

The programmed death-1 receptor/ligand pair (PD-1/PD-L1) functions to temper T cell activation. Mice lacking PD-1 have a normal lifespan while exhibiting T cell expansion in their lymphoid tissue. We explored this mutant further focusing on B cell biology. By flow cytometry, C57Bl/6J PD-1−/− spleen (SP) B cells were similar to those of wildtype (WT) mice. However, their peritoneal cavity (PerC) B cells had more IgMloIgDhi B cells (B2 subset) and fewer CD11bloCD19+ and CD5loCD19+ B cells (B1b/B1a subsets). Consistent with their B cell expansion, serum IgM, IgG3, IgG1, and IgA levels were 1.5–2.5 fold greater in PD-1−/− mice. Likewise, responses to thymus-dependent (FITC-OVA) and thymus-independent type-1 and −2 antigens (FITC-LPS, FITC-DEX) were greater than those of WT mice. As expected from prior studies, more activated or effector/memory (CD25+CD62L−CD44+) CD4+ T cells were found in the PD-1−/− SP. However this was not the case in the PerC where CD8+CD62L−CD44+ T cells were increased relative to WT. The latter likely contributed to the 3-fold greater level of IFNg production found for PD-1−/− PerC cells. PerC B2 cell expansion was less evident in older mice, perhaps reflecting sequelae of thymic involution with aging. These observations will be discussed in the context of T cell modulation impacting B cell biology. Supported by NIH AREA program (R15 AI 060356-01, R15 CA 136901). Supported by NIH AREA program grants R15 AI 060356-01 and R15 CA 136901.

Atypical cytokine production and immune cell subset ratios, particularly those that include high proportions of macrophages, characterize tumor microenvironments (TMEs). TMEs can be modeled by culturing peritoneal cavity (PerC) cells which have a high macrophage to lymphocyte ratio. With TCR or BCR ligation, PerC lymphocyte proliferation is tempered by macrophages. However, PHA (T cells) and anti-CD40 (B cells) are activators that induce proliferation. Herein, we report that ligating IgD, in contrast to IgM, triggers PerC B cell proliferation. IL-4 addition enhanced the IgD response for BALB/c PerC B cells but suppressed that of C57BL/6 mice. Intriguingly, concurrent ligation of IgD and CD3(ε) rescued a PerC T cell proliferative response. These results serve to expand the list of targets for promoting cellular and humoral immunity in conditions that model macrophage-rich TMEs.

The optimization of a new class of small molecule PCSK9 mRNA translation inhibitors is described. The potency, physicochemical properties, and off-target pharmacology associated with the hit compound (1) were improved by changes to two regions of the molecule. The last step in the synthesis of the congested amide center was enabled by three different routes. Subtle structural changes yielded significant changes in pharmacology and off-target margins. These efforts led to the identification of 7l and 7n with overall profiles suitable for in vivo evaluation. In a 14-day toxicology study, 7l demonstrated an improved safety profile vs lead 7f. We hypothesize that the improved safety profile is related to diminished binding of 7l to nontranslating ribosomes and an apparent improvement in transcript selectivity due to the lower strength of 7l stalling of off-target proteins.

We introduce a model that extends the standard vote choice model to encompass text. In our model, votes and speech are generated from a common set of underlying preference parameters. We estimate the parameters with a sparse Gaussian copula factor model that estimates the number of latent dimensions, is robust to outliers, and accounts for zero inflation in the data. To illustrate its workings, we apply our estimator to roll call votes and floor speech from recent sessions of the US Senate. We uncover two stable dimensions: one ideological and the other reflecting to Senators’ leadership roles. We then show how the method can leverage common speech in order to impute missing data, recovering reliable preference estimates for rank-and-file Senators given only leadership votes.

Targeting of the human ribosome is an unprecedented therapeutic modality with a genome-wide selectivity challenge. A liver-targeted drug candidate is described that inhibits ribosomal synthesis of PCSK9, a lipid regulator considered undruggable by small molecules. Key to the concept was the identification of pharmacologically active zwitterions designed to be retained in the liver. Oral delivery of the poorly permeable zwitterions was achieved by prodrugs susceptible to cleavage by carboxylesterase 1. The synthesis of select tetrazole prodrugs was crucial. A cell-free in vitro translation assay containing human cell lysate and purified target mRNA fused to a reporter was used to identify active zwitterions. In vivo PCSK9 lowering by oral dosing of the candidate prodrug and quantification of the drug fraction delivered to the liver utilizing an oral positron emission tomography 18F-isotopologue validated our liver-targeting approach.

Compounds that contain the 1-heteroaryl-3-azabicyclo[3.1.0]hexane architecture are of particular interest to the pharmaceutical industry yet remain a challenge to synthesize. We report herein an expedient and modular approach to the synthesis of 1-heteroaryl-3-azabicyclo[3.1.0]hexanes by Suzuki–Miyaura and Chan–Evans–Lam coupling reactions of tertiary trifluoroborate salts. Our Suzuki–Miyaura cross-coupling protocol is compatible with a broad range of aryl and heteroaryl bromides and chlorides. The unprecedented Chan–Evans–Lam coupling of tertiary trifluoroborates allows the facile construction of 1-heteroaryl-3-azabicyclo[3.1.0]hexanes containing C-tertiary arylamines at the ring juncture.

In lymphopenic environments, secondary lymphoid organs regulate the size of B and T cell compartments by supporting homeostatic proliferation of mature lymphocytes. Although this process operates in multiple clinically relevant settings, including after bone marrow transplantation and chemotherapy as well as in aging individuals, little is known about its underlying molecular mechanisms and functional consequences. In mice, mature naïve B cells include mostly follicular B (FoB) cells in spleen and lymph nodes, as well as specialized marginal zone B (MZB) cells in the spleen with innate-like functions and a capacity for rapid plasma cell differentiation. To identify mechanisms controlling the size and composition of the peripheral B cell pool, we developed a mouse model in which highly purified CTV-labelled B6-CD45.1 FoB cells were adoptively transferred intravenously to lymphopenic B6-CD45.2 Rag2-/- mice, lacking mature B and T cells, or control B6-CD45.2 lymphoid-replete recipients. Within two days after transfer of CD19+ CD93neg CD21int CD23high B6-CD45.1 FoB cells (106, >99% purity), CD45.1+ donor-derived B cells had upregulated expression of surface IgM (sIgM) and CD21 in the spleen of Rag2-/- recipients, but not in wild type control recipients. At day 4 and day 8, the majority of transferred B cells remained sIgMhi and CD21hi in Rag2-/- recipients and gradually showed decreased CD23 and sIgD as well as increased CD1d expression, consistent with loss of their FoB phenotype and acquisition of a characteristic MZB cell phenotype (sIgMhisIgDlow CD21hi CD1dhi CD23low). These phenotypic changes were followed by a burst of proliferation (CTV dilution) between day 4 and day 8 after transfer. Immunofluorescence microscopy of host Rag2-/- spleen sections at day 2 post-transfer identified clusters of transferred B cells localized around CD169+ macrophages at the white pulp/red pulp interface close to the marginal sinus, with subsequent proliferation in this area. We next investigated if Notch signaling regulates this transdifferentiation process, by analogy to its role in normal MZB cell homeostasis. Treatment of Rag2-/- recipients with blocking antibodies against Delta-like-1 Notch ligands (anti-DLL1) or Notch2 receptors (anti-NRR2) completely inhibited lymphopenia-induced FoB to MZB cell conversion and proliferation. To identify the cellular source of DLL1 Notch ligands, we studied transferred B cells in Rag2-/-;Ccl19-Cre+;Dll1f/f recipients, lacking Dll1 expression in all Ccl19-Cre+ fibroblastic reticular cells and their progeny. In these mice as compared to Rag2-/- recipients, FoB to MZB transdifferentiation was almost completely abrogated and transferred cells no longer clustered with marginal sinus-associated macrophages. Thus, stromal DLL1 Notch ligands are critical to regulate the size and composition of the splenic peripheral B cell pool in lymphopenic mice through DLL1/Notch2 interactions. Furthermore, FoB cells are not locked in their FoB cell fate, as commonly assumed, but are instead endowed with plastic transdifferentiation potential in response to DLL1/Notch2-mediated signals that function as a sensor of B cell lymphopenia. We speculate that these adaptive physiological functions of the Notch signaling pathway play an important role in the homeostasis of mature B cells within their stromal microenvironment, and that they can be hijacked during malignant transfomation in Notch-dependent mature B cell lymphomas such as CLL and marginal zone lymphoma. Disclosures Siebel: Genentech: Current Employment. Maillard:Allogene: Consultancy; Regeneron: Consultancy; Genentech: Consultancy.

Molecules containing trifluoromethoxyaryl groups are of interest in pharmaceutical, agrochemical, and materials science research, due to their unique physical and electronic properties. Many of the known methods to synthesize aryl trifluoromethyl ethers require harsh reagents and highly controlled reaction conditions and rarely occur when heteroaromatic units are present. The two-step O-trifluoromethylation of phenols via aryl xanthates is one such method that suffers from these drawbacks. Herein, we report a method for the synthesis of aryl trifluoromethyl ethers from phenols by the facile conversion of the phenol to the corresponding aryl and heteroaryl xanthates with newly synthesized imidazolium methylthiocarbonothioyl salts and conversion of these xanthates to the trifluoromethyl ethers under mild reaction conditions.

A robust approach to gem -dialkylbenzyl heterocycles has been developed through a triflic acid-catalyzed hydroarylation of olefinic heterocycles. A broad range of substrates containing pyridine, quinoline, pyrazole, triazole and imidazole moieties are shown to be highly compatible with this method. This rapid construction of gem -dialkyl groups should be useful in the synthesis of drug-like molecules containing heterocyclic diversity and in the study of the gem -dialkyl effect.

The cornea is avascular, which makes it an excellent model to study matrix protein expression and tissue stiffness. The corneal epithelium adheres to the basement zone and the underlying stroma is composed of keratocytes and an extensive matrix of collagen and proteoglycans. Our goal was to examine changes in corneas of 8- and 15-week mice and compare them to 15-week pre-Type 2 diabetic obese mouse. Nanoindentation was performed on corneal epithelium in situ and then the epithelium was abraded, and the procedure repeated on the basement membrane and stroma. Confocal imaging was performed to examine the localization of proteins. Stiffness was found to be age and obesity dependent. Young&rsquo, s modulus was greater in the epithelium from 15-week mice compared to 8-week mice. At 15 weeks, the epithelium of the control was significantly greater than that of the obese mice. There was a difference in the localization of Crb3 and PKC&zeta, in the apical epithelium and a lack of lamellipodial extensions in the obese mouse. In the pre-Type 2 diabetic obese mouse there was a difference in the stiffness slope and after injury localization of fibronectin was negligible. These indicate that age and environmental changes incurred by diet alter the integrity of the tissue with age rendering it stiffer. The corneas from the pre-Type 2 diabetic obese mice were significantly softer and this may be a result of changes both in proteins on the apical surface indicating a lack of integrity and a decrease in fibronectin.

A series of N-(piperidin-3-yl)-N-(pyridin-2-yl)piperidine/piperazine-1-carboxamides were identified as small molecule PCSK9 mRNA translation inhibitors. Analogues from this new chemical series, such as 4d and 4g, exhibited improved PCSK9 potency, ADME properties, and in vitro safety profiles when compared to earlier lead structures.

Tumors may include a high proportion of immune modulatory cells and molecules that restrain the anti-cancer response. Activation of T cells to eliminate cancer cells within the immune-suppressive tumor microenvironment remains a challenge. We have shown that C57BL/6J peritoneal cell culture models features of macrophage-dense tumors as TCR ligation fails to activate T cells unless IFNγ is neutralized or iNOS is inhibited. We tested other forms of T cell activation and found phytohemagglutinin (PHA) distinctive in the ability to markedly expand CD8 T cells in this model. IFNγ or iNOS inhibition was not necessary for this response. PHA triggered less IFNγ production and inhibitory PD-L1 expression than TCR ligation. Macrophages and CD44(hi) T cells bound PHA. Spleen T cell responses to PHA were markedly enhanced by the addition of peritoneal cells revealing that macrophages enhance T cell expansion. That PHA increases CD8 T cell responses within macrophage-dense culture suggests this mitogen might enhance anti-tumor immunity.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a key role in regulating the levels of plasma low-density lipoprotein cholesterol (LDL-C). Here, we demonstrate that the compound PF-06446846 inhibits translation of PCSK9 by inducing the ribosome to stall around codon 34, mediated by the sequence of the nascent chain within the exit tunnel. We further show that PF-06446846 reduces plasma PCSK9 and total cholesterol levels in rats following oral dosing. Using ribosome profiling, we demonstrate that PF-06446846 is highly selective for the inhibition of PCSK9 translation. The mechanism of action employed by PF-06446846 reveals a previously unexpected tunability of the human ribosome that allows small molecules to specifically block translation of individual transcripts.

C–X–C chemokine receptor type 7 (CXCR7) is involved in cardiac and immune pathophysiology. We report the discovery of a novel 1,4-diazepine CXCR7 modulator, demonstrating for the first time the role of pharmacological CXCR7 intervention in cardiac repair. Structure–activity-relationship (SAR) studies demonstrated that a net reduction in lipophilicity (log D) and an incorporation of saturated ring systems yielded compounds with good CXCR7 potencies and improvements in oxidative metabolic stability in human-liver microsomes (HLM). Tethering an ethylene amide further improved the selectivity profile (e.g., for compound 18, CXCR7 Ki = 13 nM, adrenergic α 1a Kb > 10 000 nM, and adrenergic β 2 Kb > 10 000 nM). The subcutaneous administration of 18 in mice led to a statistically significant increase in circulating concentrations of plasma stromal-cell-derived factor 1α (SDF-1α) of approximately 2-fold. Chronic dosing of compound 18 in a mouse model of isoproterenol-induced cardiac injury further resulted in a st...

Tumors are often comprised of microenvironments (TMEs) with a high proportion of cells and molecules that regulate immunity. Peritoneal cavity (PerC) cell culture reproduces key features of TMEs as lymphocyte proliferation is suppressed by PerC macrophages (Mϕs). We monitored the expression of T cell stimulatory (Class II MHC, B7) and inhibitory (PD-L1) molecules by PerC APCs before and after culture and report here that IFNγ-driven PD-L1 expression increased markedly on PerC Mϕs after TCR ligation, even more so than seen with direct APC activation by LPS. Considering the high APC composition of and pronounced PD-L1 expression by PerC cells, it was surprising that blocking PD-1/PD-L1 interaction by mAb neutralization or genetic ablation did not relieve suppression. This result parallels TME challenges observed in the clinic and validates the need for further study of this culture model to inform strategies to promote anti-tumor immunity.

Recent studies in adipose tissue, pancreas, muscle, and macrophages suggest that MAP4K4, a serine/threonine protein kinase may be a viable target for antidiabetic drugs. As part of the evaluation of MAP4K4 as a novel antidiabetic target, a tool compound, 16 (PF-6260933) and a lead 17 possessing excellent kinome selectivity and suitable properties were delivered to establish proof of concept in vivo. The medicinal chemistry effort that led to the discovery of these lead compounds is described herein together with in vivo pharmacokinetic properties and activity in a model of insulin resistance.

Inhibition of triacylglycerol (TAG) biosynthetic enzymes has been suggested as a promising strategy to treat insulin resistance, diabetes, dyslipidemia, and hepatic steatosis. Monoacylglycerol acyltransferase 3 (MGAT3) is an integral membrane enzyme that catalyzes the acylation of both monoacylglycerol (MAG) and diacylglycerol (DAG) to generate DAG and TAG, respectively. Herein, we report the discovery and characterization of the first selective small molecule inhibitors of MGAT3. Isoindoline-5-sulfonamide (6f, PF-06471553) selectively inhibits MGAT3 with high in vitro potency and cell efficacy. Because the gene encoding MGAT3 (MOGAT3) is found only in higher mammals and humans, but not in rodents, a transgenic mouse model expressing the complete human MOGAT3 was used to characterize the effects of 6f in vivo. In the presence of a combination of diacylglycerol acyltransferases 1 and 2 (DGAT1 and DGAT2) inhibitors, an oral administration of 6f exhibited inhibition of the incorporation of deuterium-labeled glycerol into TAG in this mouse model. The availability of a potent and selective chemical tool and a humanized mouse model described in this report should facilitate further dissection of the physiological function of MGAT3 and its role in lipid homeostasis.

I offer a model of the sustainability of authoritarian rule in which the transparency of productive economic activity enables the ruler to distinguish productive economic activity from preparations for rebellion. The less transparent the productive technology the greater the economic side effects of maintaining authoritarian rule, and the stronger the incentives to liberalize the regime. Using a cross section of countries I provide evidence that, consistently with the theory, democratic government Granger causes internet penetration.

Macrocyclic peptides were designed and synthesized for secondary structural analysis. A PyBroP-based cyclization protocol was employed and was facilitated by solid-phase synthesis. After systematic NMR analyses of each macrocycle, multiple structures were found to exist as 3 10 -helices.

Compounds that contain the 1-heteroaryl-3-azabicyclo[3.1.0]hexane architecture are of particular interest to the pharmaceutical industry yet remain a challenge to synthesize. We report herein an expedient and modular approach to the synthesis of 1-heteroaryl-3-azabicyclo[3.1.0]hexanes by Suzuki-Miyaura and Chan-Evans-Lam coupling reactions of tertiary trifluoroborate salts. Our Suzuki-Miyaura cross-coupling protocol is compatible with a broad range of aryl and heteroaryl bromides and chlorides. The unprecedented Chan-Evans-Lam coupling of tertiary trifluoroborates allows the facile construction of 1-heteroaryl-3-azabicyclo[3.1.0]hexanes containing C-tertiary arylamines at the ring juncture.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a key role in regulating the levels of plasma low-density lipoprotein cholesterol (LDL-C). Here, we demonstrate that the compound PF-06446846 inhibits translation of PCSK9 by inducing the ribosome to stall around codon 34, mediated by the sequence of the nascent chain within the exit tunnel. We further show that PF-06446846 reduces plasma PCSK9 and total cholesterol levels in rats following oral dosing. Using ribosome profiling, we demonstrate that PF-06446846 is highly selective for the inhibition of PCSK9 translation. The mechanism of action employed by PF-06446846 reveals a previously unexpected tunability of the human ribosome that allows small molecules to specifically block translation of individual transcripts., Author summary Many disease-mediating proteins have proven difficult to target with traditional small-molecule pharmaceuticals. In this paper, we report that a small molecule, PF-06446846, directly inhibits translation of one such protein, proprotein convertase subtilisin/kexin type 9 (PCSK9), by acting on the translating human ribosome. PF-06446846 causes the translating ribosome to stall soon after translating the PCSK9 signal sequence. We further show that PF-06446846 activity is dependent on the amino acid sequence of the nascent chain inside the ribosome exit tunnel. In a rat safety study, we observe decreases in plasma PCSK9, total cholesterol, and low-density lipoprotein (LDL) cholesterol. Using mass spectrometry in cell culture and ribosome profiling, we demonstrate that despite acting on the ribosome, which synthesizes every protein in the cell, PF-06446846 displays a high level of selectivity for PCSK9. This unexpected potential for small molecules to selectively inhibit the human ribosome opens the possibility for future development of small molecules targeting disease-mediating proteins that were previously thought to be undruggable.