Understanding the Coacervate-to-Vesicle Transition of Globular Fusion Proteins to Engineer Protein Vesicle Size and Membrane Heterogeneity.

Protein-rich coacervates are liquid phases separate from the aqueous bulk phase that are used by nature for compartmentalization and more recently have been exploited by engineers for delivery and formulation applications. They also serve as an intermediate phase in an assembly path to more complex structures, such as vesicles. Recombinant fusion protein complexes made from a globular protein fused with a glutamic acid-rich leucine zipper (globule-ZE) and an arginine-rich leucine zipper fused with an elastin-like polypeptide (ZR-ELP) show different phases from soluble, through an intermediate coacervate phase, and finally to vesicles with increasing temperature of the aqueous solution. We investigated the phase transition kinetics of the fusion protein complexes at different temperatures using dynamic light scattering and microscopy, along with mathematical modeling. We controlled coacervate growth by aging the solution at an intermediate temperature that supports coacervation and confirmed that the size of the coacervate droplets dictates the size of vesicles formed upon further heating. With this understanding of the phase transition, we developed strategies to induce heterogeneity in the organization of globular proteins in the vesicle membrane through simple mixing of coacervates containing two different globular fusion proteins prior to the vesicle transition. This study gives fundamental insights and practical strategies for development of globular protein-rich coacervates and vesicles for drug delivery, microreactors, and protocell applications.

Dual Exosite-binding Inhibitors of Insulin-degrading Enzyme Challenge Its Role as the Primary Mediator of Insulin Clearance in Vivo.

Insulin-degrading enzyme (IDE, insulysin) is the best characterized catabolic enzyme implicated in proteolysis of insulin. Recently, a peptide inhibitor of IDE has been shown to affect levels of insulin, amylin, and glucagon in vivo. However, IDE(-/-) mice display variable phenotypes relating to fasting plasma insulin levels, glucose tolerance, and insulin sensitivity depending on the cohort and age of animals. Here, we interrogated the importance of IDE-mediated catabolism on insulin clearance in vivo. Using a structure-based design, we linked two newly identified ligands binding at unique IDE exosites together to construct a potent series of novel inhibitors. These compounds do not interact with the catalytic zinc of the protease. Because one of these inhibitors (NTE-1) was determined to have pharmacokinetic properties sufficient to sustain plasma levels >50 times its IDE IC50 value, studies in rodents were conducted. In oral glucose tolerance tests with diet-induced obese mice, NTE-1 treatment improved the glucose excursion. Yet in insulin tolerance tests and euglycemic clamp experiments, NTE-1 did not enhance insulin action or increase plasma insulin levels. Importantly, IDE inhibition with NTE-1 did result in elevated plasma amylin levels, suggesting the in vivo role of IDE action on amylin may be more significant than an effect on insulin. Furthermore, using the inhibitors described in this report, we demonstrate that in HEK cells IDE has little impact on insulin clearance. In total, evidence from our studies supports a minimal role for IDE in insulin metabolism in vivo and suggests IDE may be more important in helping regulate amylin clearance.

Characterization and preclinical development of LY2603618: a selective and potent Chk1 inhibitor.

Interference with DNA damage checkpoints has been demonstrated preclinically to be a highly effective means of increasing the cytotoxicity of a number of DNA-damaging cancer therapies. Cell cycle arrest at these checkpoints protects injured cells from apoptotic cell death until DNA damage can be repaired. In the absence of functioning DNA damage checkpoints, cells with damaged DNA may proceed into premature mitosis followed by cell death. A key protein kinase involved in activating and maintaining the S and G2/M checkpoints is Chk1. Pharmacological inhibition of Chk1 in the absence of p53 functionality leads to abrogation of DNA damage checkpoints and has been shown preclinically to enhance the activity of many standard of care chemotherapeutic agents. LY2603618 is a potent and selective small molecule inhibitor of Chk1 protein kinase activity in vitro (IC(50) = 7 nM) and the first selective Chk1 inhibitor to enter clinical cancer trials. Treatment of cells with LY2603618 produced a cellular phenotype similar to that reported for depletion of Chk1 by RNAi. Inhibition of intracellular Chk1 by LY2603618 results in impaired DNA synthesis, elevated H2A.X phosphorylation indicative of DNA damage and premature entry into mitosis. When HeLa cells were exposed to doxorubicin to induce a G2/M checkpoint arrest, subsequent treatment with LY2603618 released the checkpoint, resulting in cells entering into metaphase with poorly condensed chromosomes. Consistent with abrogation of the Chk1 and p53-dependent G2/M checkpoint, mutant TP53 HT-29 colon cancer cells were more sensitive to gemcitabine when also treated with LY2603618, while wild-type TP53 HCT116 cells were not sensitized by LY2603618 to gemcitabine. Treatment of Calu-6 human mutant TP53 lung cancer cell xenografts with gemcitabine resulted in a stimulation of Chk1 kinase activity that was inhibited by co-administration of LY2603618. By all criteria, LY2603618 is a highly effective inhibitor of multiple aspects of Chk1 biology.

Identification of LY3522348: A Highly Selective and Orally Efficacious Ketohexokinase Inhibitor.

The identification of clinical candidate LY3522348 (compound 23) is described. LY3522348 is a highly selective, oral dual inhibitor of human ketohexokinase isoforms C and A (hKHK-C, hKHK-A). Optimization began with highly efficient (S)-2-(2-methylazetidin-1-yl)-6-(1H-pyrazol-4-yl)-4-(trifluoromethyl)nicotinonitrile (3). Efforts focused on developing absorption, distribution, metabolism, potency, and in vitro safety profiles to support oral QD dosing in patients. Structure-based design leveraged vectors for substitution of the pyrazole ring, which provided an opportunity to interact with several different proximal amino acid residues in the protein. LY3522348 displayed a robust pharmacodynamic response in a mouse model of fructose metabolism and was advanced into clinical trials.

Non-clinical immunological comparison of a Next-Generation 24-valent pneumococcal conjugate vaccine (VAX-24) using site-specific carrier protein conjugation to the current standard of care (PCV13 and PPV23).

Despite widespread utilization of pneumococcal conjugate vaccines (PCVs) and the resultant disease reduction, the development of PCVs containing additional serotypes remains a public health priority due to serotype replacement and the resultant shift to non-vaccine containing serotypes. However, incorporating additional serotypes to existing PCVs using conventional technologies has proven problematic. Immune responses to individual serotypes have consistently decreased as more polysaccharide-conjugates are added due to carrier suppression. Using our proprietary cell-free protein synthesis (CFPS) platform, we have successfully produced eCRM® based on the CRM197 sequence for use as an enhanced carrier protein to develop a 24-valent PCV. The eCRM carrier protein contains multiple non-native amino acids (nnAAs) located outside of the primary T-cell epitope regions, thereby enabling site-specific covalent conjugation of the pneumococcal polysaccharides to the nnAAs to consistently expose the critical T-cell epitopes. eCRM also serves to reduce structural heterogeneity associated with classic reductive-amination conjugation while promoting formation of the conjugate matrix structures, the hallmark of PCVs. This process serves to increase the overall polysaccharide:protein ratio, enabling the inclusion of more serotypes while minimizing carrier-mediated immunological interference. The aim of this non-clinical study was to construct a 24-valent PCV and evaluate its immunogenicity. Using the XPressCF® CFPS platform, the eCRM carrier protein was separately conjugated through nnAAs to each of the 24 pneumococcal polysaccharides through click chemistry and mixed with aluminum phosphate to produce VAX-24, Vaxcyte's proprietary PCV preclinical candidate. VAX-24, Prevnar13® and Pneumovax®23 were administered to New Zealand White rabbits to compare the resulting opsonophagocytic activity (OPA) and anti-capsular IgG antibodies. VAX-24 showed conjugate-like immune responses to all 24 serotypes based on comparable OPA and IgG responses to Prevnar13 and higher responses than Pneumovax 23. This study demonstrates the utility of site-specific conjugation technology in a preclinical setting and the potential for a PCV with improved serotype coverage.

Defining Target Engagement Required for Efficacy In Vivo at the Retinoic Acid Receptor-Related Orphan Receptor C2 (RORγt).

The Th17 pathway has been implicated in autoimmune diseases. The retinoic acid receptor-related orphan receptor C2 (RORγt) is a master regulator of Th17 cells and controls the expression of IL-17A. RORγt is expressed primarily in IL-17A-producing lymphoid cells. Here we describe a virtual screen of the ligand-binding pocket and subsequent screen in a binding assay that identified the 1-benzyl-4',5'-dihydrospiro[piperidine-4,7'-thieno[2,3-c]pyran]-2'-carboxamide scaffold as a starting point for optimization of binding affinity and functional activity guided by structure-based design. Compound 12 demonstrated activity in a mouse PK/PD model and efficacy in an inflammatory arthritis mouse model that were used to define the level and duration of target engagement required for efficacy in vivo. Further optimization to improve ADME and physicochemical properties with guidance from simulations and modeling provided compound 22, which is projected to achieve the level and duration of target engagement required for efficacy in the clinic.

Gender, stressful life events and interactions with sleep: a systematic review of determinants of adiposity in young people.

OBJECTIVES: Overweight and obesity among young people are high and rising. Social stressors and sleep are independently associated with obesity, but are rarely studied together or examined for gender-specific effects. The literature regarding adolescent populations is especially lacking. This review assesses whether experiencing stressful life events results in greater adiposity in young women and young men compared with those who do not experience stressful life events, and whether the relationship is modified by sleep problems. DESIGN: We systematically searched six bibliometric databases (Web of Science, Embase Ovid, PsycINFO, CINHAL, PubMed, ProQuest Dissertations) supplemented by hand searches. Longitudinal prospective studies or reviews were eligible for inclusion when they examined gender-specific changes in adiposity in young adults (age 13-18 years) as a function of stressful life event alone or in combination with sleep problems. RESULTS: We found one study eligible for inclusion reporting mixed impact of stressful life events on body mass index (BMI) between genders. The study assessed specific life events and showed significantly lower BMI at follow-up among young men who experienced a residence change, but significantly higher BMI among young women who experienced setting up a family and who reported internal locus of control. CONCLUSIONS: Despite ample research on social stressors or sleep problems and weight, we still know little about the role of stressful life events, or combined effects with sleep, on obesity risk in adolescents from a gender perspective. Existing evidence suggests specific life events affect weight differently between the genders. Robust, high-quality longitudinal studies to decipher this dual burden on obesity during adolescence should be prioritised, as firm conclusions remain elusive.

Benzopyrans are selective estrogen receptor beta agonists with novel activity in models of benign prostatic hyperplasia.

Benzopyran selective estrogen receptor beta agonist-1 (SERBA-1) shows potent, selective binding and agonist function in estrogen receptor beta (ERbeta) in vitro assays. X-ray crystal structures of SERBA-1 in ERalpha and beta help explain observed beta-selectivity of this ligand. SERBA-1 in vivo demonstrates involution of the ventral prostate in CD-1 mice (ERbeta effect), while having no effect on gonadal hormone levels (ERalpha effect) at 10x the efficacious dose, consistent with in vitro properties of this molecule.

Discovery of 1-(3,3-dimethylbutyl)-3-(2-fluoro-4-methyl-5-(7-methyl-2-(methylamino)pyrido[2,3-d]pyrimidin-6-yl)phenyl)urea (LY3009120) as a pan-RAF inhibitor with minimal paradoxical activation and activity against BRAF or RAS mutant tumor cells.

The RAS-RAF-MEK-MAPK cascade is an essential signaling pathway, with activation typically mediated through cell surface receptors. The kinase inhibitors vemurafenib and dabrafenib, which target oncogenic BRAF V600E, have shown significant clinical efficacy in melanoma patients harboring this mutation. Because of paradoxical pathway activation, both agents were demonstrated to promote growth and metastasis of tumor cells with RAS mutations in preclinical models and are contraindicated for treatment of cancer patients with BRAF WT background, including patients with KRAS or NRAS mutations. In order to eliminate the issues associated with paradoxical MAPK pathway activation and to provide therapeutic benefit to patients with RAS mutant cancers, we sought to identify a compound not only active against BRAF V600E but also wild type BRAF and CRAF. On the basis of its superior in vitro and in vivo profile, compound 13 was selected for further development and is currently being evaluated in phase I clinical studies.

High level accumulation of alpha-glucan in maize kernels by expressing the gtfD gene from Streptococcus mutans.

Glucosyltransferases (GTFs, EC.2.4.1.5) are bacterial enzymes that catalyze the polymerization of glucose residues from sucrose, leading to the production of high molecular weight glucan with alpha-1,3 /alpha-1,6 linkages. Such glucans, with many potential food and industrial applications, do not normally exist in higher plants. We fused a mutant form of the gtfD gene from Sreptococcus mutans with the maize (Zea mays L.) chloroplastic Brittle 1 transit peptide for amyloplast targeting. This construct, driven by the ubiquitin promoter, was introduced into maize by Agrobacterium-mediated transformation. We developed a novel HPLC-based method that enabled us differentially to distinguish transgene glucan from other endogenous polysaccharides in maize kernels. Using this method, we screened over 100 transgenic plants for the presence of GTF-produced glucan whose content varied between 0.8 and 14% of dry weight in the mature transgenic seeds. The mature transgenic plants were indistinguishable from wildtype plants in growth rate and morphology. Furthermore, starch granule size in the transgenic maize kernel was unaffected by the accumulation of the foreign polysaccharide. Mutation in Sh2, which encodes a subunit of ADP-glucose pyrophosphorylase, had no effect on glucan accumulation caused by gtfD expression. Our results indicated that high levels of novel carbohydrate polymer can be accumulated in crop plants through transgene technology.