Discovery of triazolopyrimidine-based PDE8B inhibitors: exceptionally ligand-efficient and lipophilic ligand-efficient compounds for the treatment of diabetes.

PDE8B is a cAMP-specific isoform of the broader class of phosphodiesterases (PDEs). As no selective PDE8B inhibitors had been reported, a high throughput screen was run with the goal of identifying selective tools for exploring the potential therapeutic utility of PDE8B inhibition. Of the numerous hits, one was particularly attractive since it was amenable to rapid deconstruction leading to inhibitors with very high ligand efficiency (LE) and lipophilic ligand efficiency (LLE). These triazolopyrimidines were optimized for potency, selectivity and ADME properties ultimately leading to compound 42. This compound was highly potent and selective with good bioavailability and advanced into pre-clinical development.

1-((3S,4S)-4-amino-1-(4-substituted-1,3,5-triazin-2-yl) pyrrolidin-3-yl)-5,5-difluoropiperidin-2-one inhibitors of DPP-4 for the treatment of type 2 diabetes.

A 3-amino-4-substituted pyrrolidine series of dipeptidyl peptidase IV (DPP-4) inhibitors was rapidly developed into a candidate series by identification of a polar valerolactam replacement for the lipophilic 2,4,5-trifluorophenyl pharmacophore. The addition of a gem-difluoro substituent to the lactam improved overall DPP-4 inhibition and an efficient asymmetric route to 3,4-diaminopyrrolidines was developed. Advanced profiling of a subset of analogs identified 5o with an acceptable human DPP-4 inhibition profile based on a rat PK/PD model and a projected human dose that was suitable for clinical development.

Brief intervention of low carbohydrate dietary advice: clinic results and a review of the literature.

PURPOSE OF REVIEW: The purpose of the review is to assess the efficacy of a brief intervention of low carbohydrate dietary advice for weight loss in patients with a raised body mass index (BMI) (>25 kg/m2) during routine patient appointments in primary care. RECENT FINDINGS: Brief interventions in primary care have been shown to be a valuable tool in supporting patients to make lifestyle changes. Low carbohydrate diets have been successful in helping patients lose weight.The authors carried out a retrospective observational study based on the electronic records from a single general practitioner surgery with 7,500 patients in Essex, UK. Low carbohydrate dietary advice was given opportunistically to patients with a raised BMI, over an 18 month period, with advice and weights recorded. In total, 774 patients were given low carbohydrate dietary advice. Overall, 1103 kg of weight was lost by 339 patients, there was a median weight loss of 2.5 kg (interquartile range 0.0-6.0 kg) and a mean weight loss of 3.3 kg. SUMMARY: There is no published literature available assessing the efficacy of brief interventions of low carbohydrate dietary advice. Our clinic results indicate that this may be an effective weight loss tool in primary care.

Atezolizumab plus bevacizumab versus sorafenib or atezolizumab alone for unresectable hepatocellular carcinoma: A systematic review.

BACKGROUND: Despite the use of current standard therapy, the prognosis of patients with unresectable hepatocellular carcinoma (HCC) is poor, with median survival times of 40 mo for intermediate HCC (Barcelona Clinic Liver Cancer [BCLC] stage B) and 6-8 mo for advanced HCC (BCLC stage C). Although patients with early-stage HCC are usually suitable for therapies with curative intention, up to 70% of patients experience relapse within 5 years. In the past decade, the United States Food and Drug Administration has approved different immunogenic treatment options for advanced HCC, the most common type of liver cancer among adults. Nevertheless, no treatment is useful in the adjuvant setting. Since 2007, the multi-kinase inhibitor sorafenib has been used as a first-line targeted drug to address the increased mortality and incidence rates of HCC. However, in 2020, the IMbrave150 trial demonstrated that combination therapy of atezolizumab (anti-programmed death-ligand 1 [PD-L1]) and bevacizumab (anti-vascular endothelial growth factor [VEGF]) is superior to sorafenib, a single anti-programmed death 1/PD-L1 antibody inhibitor used as an anti-cancer monotherapy for HCC treatment. AIM: To conduct a systematic literature review to evaluate the evidence supporting the efficacy and safety of atezolizumab/bevacizumab as preferred first-line drug therapy over the conventional sorafenib or atezolizumab monotherapies, which are used to improve survival outcomes and reduce disease progression in patients with unresectable HCC and non-decompensated liver disease. METHODS: A comprehensive literature review was conducted using the PubMed, Scopus, ScienceDirect, clinicaltrials.gov, PubMed Central, Embase, EuropePMC, and CINAHL databases to identify studies that met the inclusion criteria using relevant MeSH terms. This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and risk of bias (RoB) were assessed using the Cochrane RoB 2 tool and Sevis. RESULTS: In the atezolizumab/bevacizumab group, an improvement in overall tumor response, reduction of disease progression, and longer progression-free survival were observed compared to monotherapy with either sorafenib or atezolizumab. Hypertension and proteinuria were the most common adverse events, and the rates of adverse events were comparable to those with the monotherapy. Of the studies, there were two completed trials and two ongoing trials analyzed using high quality and low bias. A more thorough analysis was only performed on the completed trials. CONCLUSION: Treatment of HCC with atezolizumab/bevacizumab combination therapy was confirmed to be an effective first-line treatment to improve survival in patients with unresectable HCC and non-decompensated liver disease compared to monotherapy with either sorafenib or atezolizumab.

Piperidinyl-2-phenethylamino inhibitors of DPP-IV for the treatment of type 2 diabetes.

A highly ligand efficient lead molecule was rapidly developed into a DPP-IV selective candidate series using focused small library synthesis. A significant hurdle for series advancement was genetic safety since some agents in this series impaired chromosome division that was detected using the in vitro micronucleus assay. A recently developed high-throughput imaging-based in vitro micronucleus assay enabled the identification of chemical space with a low probability of micronucleus activity. Advanced profiling of a subset within this space identified a compound with a clean safety profile, an acceptable human DPP-IV inhibition profile based on the rat PK/PD model and a projected human dose that was suitable for clinical development.

(3,3-Difluoro-pyrrolidin-1-yl)-[(2S,4S)-(4-(4-pyrimidin-2-yl-piperazin-1-yl)-pyrrolidin-2-yl]-methanone: a potent, selective, orally active dipeptidyl peptidase IV inhibitor.

A series of 4-substituted proline amides was synthesized and evaluated as inhibitors of dipeptidyl pepdidase IV for the treatment of type 2 diabetes. (3,3-Difluoro-pyrrolidin-1-yl)-[(2S,4S)-(4-(4-pyrimidin-2-yl-piperazin-1-yl)-pyrrolidin-2-yl]-methanone (5) emerged as a potent (IC(50) = 13 nM) and selective compound, with high oral bioavailability in preclinical species and low plasma protein binding. Compound 5, PF-00734200, was selected for development as a potential new treatment for type 2 diabetes.

Pyrethroid pesticides and their metabolites in vacuum cleaner dust collected from homes and day-care centers.

Urinary metabolites of pyrethroid pesticides have been used as biomarkers to estimate human exposure to the parent insecticide. It is important to establish whether these markers are present in environments or media to which humans are exposed routinely. Failure to account for the contribution of pre-existing markers to urinary concentrations could result in risk assessments that overestimate exposure. The purpose of this study was to quantify the concentrations of 13 selected pyrethroid pesticides and their degradation products in samples of indoor dust that had been collected in vacuum cleaner bags during the children's total exposure to persistent pesticides and other persistent organic pollutants (CTEPP) study of homes and day cares in North Carolina and Ohio. Sieved contents of 85 vacuum cleaner bags were analyzed, and permethrin was found in all samples. Sixty-nine samples contained at least one additional pyrethroid, but none contained more than five pyrethroids in detectable concentrations. Resmethrin, prallethrin, and fenpropathrin were not detected in any samples, while 36 contained phenothrin. The median concentration of permethrin in the samples was 1454ng/g of dust. Excluding permethrin, pyrethroid concentrations were typically less than or equal to 100ng/g of dust. The majority of degradates were present in more than half of the dust samples, usually at concentrations of less than or equal to 100ng/g of dust. For those pyrethroids with a characteristic oxydibenzene group, the cyclopropane degradates were present at higher concentrations than the corresponding benzoic acid moieties. Using urinary concentrations of these metabolites to model human exposure to the parent pyrethroids, may over-estimate risk due to the presence of pre-existing degradates in dust.

cis-2,5-dicyanopyrrolidine inhibitors of dipeptidyl peptidase IV: synthesis and in vitro, in vivo, and X-ray crystallographic characterization.

Inhibitors of the glucagon-like peptide-1 (GLP-1) degrading enzyme dipeptidyl peptidase IV (DPP-IV) have been shown to be effective treatments for type 2 diabetes in animal models and in human subjects. A novel series of cis-2,5-dicyanopyrrolidine alpha-amino amides were synthesized and evaluated as inhibitors of dipeptidyl peptidase IV (DPP-IV) for the treatment of type 2 diabetes. 1-({[1-(Hydroxymethyl)cyclopentyl]amino}acetyl)pyrrolidine-2,5-cis-dicarbonitrile (1c) is an achiral, slow-binding (time-dependent) inhibitor of DPP-IV that is selective for DPP-IV over other DPP isozymes and proline specific serine proteases, and which has oral bioavailability in preclinical species and in vivo efficacy in animal models. The mode of binding of the cis-2,5-dicyanopyrrolidine moiety was determined by X-ray crystallography. The hydrochloride salt of 1c was further profiled for development as a potential new treatment for type 2 diabetes.

Genome-wide synthetic lethal screens identify an interaction between the nuclear envelope protein, Apq12p, and the kinetochore in Saccharomyces cerevisiae.

The maintenance of genome stability is a fundamental requirement for normal cell cycle progression. The budding yeast Saccharomyces cerevisiae is an excellent model to study chromosome maintenance due to its well-defined centromere and kinetochore, the region of the chromosome and associated protein complex, respectively, that link chromosomes to microtubules. To identify genes that are linked to chromosome stability, we performed genome-wide synthetic lethal screens using a series of novel temperature-sensitive mutations in genes encoding a central and outer kinetochore protein. By performing the screens using different mutant alleles of each gene, we aimed to identify genetic interactions that revealed diverse pathways affecting chromosome stability. Our study, which is the first example of genome-wide synthetic lethal screening with multiple alleles of a single gene, demonstrates that functionally distinct mutants uncover different cellular processes required for chromosome maintenance. Two of our screens identified APQ12, which encodes a nuclear envelope protein that is required for proper nucleocytoplasmic transport of mRNA. We find that apq12 mutants are delayed in anaphase, rereplicate their DNA, and rebud prior to completion of cytokinesis, suggesting a defect in controlling mitotic progression. Our analysis reveals a novel relationship between nucleocytoplasmic transport and chromosome stability.

Discovery of PF-5190457, a Potent, Selective, and Orally Bioavailable Ghrelin Receptor Inverse Agonist Clinical Candidate.

The identification of potent, highly selective orally bioavailable ghrelin receptor inverse agonists from a spiro-azetidino-piperidine series is described. Examples from this series have promising in vivo pharmacokinetics and increase glucose-stimulated insulin secretion in human whole and dispersed islets. A physicochemistry-based strategy to increase lipophilic efficiency for ghrelin receptor potency and retain low clearance and satisfactory permeability while reducing off-target pharmacology led to the discovery of 16h. Compound 16h has a superior balance of ghrelin receptor pharmacology and off-target selectivity. On the basis of its promising pharmacological and safety profile, 16h was advanced to human clinical trials.

Salivary enzymes are injected into xylem by the glassy-winged sharpshooter, a vector of Xylella fastidiosa.

A few phytophagous hemipteran species such as the glassy-winged sharpshooter, Homalodisca vitripennis, (Germar), subsist entirely on xylem fluid. Although poorly understood, aspects of the insect's salivary physiology may facilitate both xylem-feeding and transmission of plant pathogens. Xylella fastidiosa is a xylem-limited bacterium that causes Pierce's disease of grape and other scorch diseases in many important crops. X. fastidiosa colonizes the anterior foregut (precibarium and cibarium) of H. vitripennis and other xylem-feeding vectors. Bacteria form a dense biofilm anchored in part by an exopolysaccharide (EPS) matrix that is reported to have a ß-1,4-glucan backbone. Recently published evidence supports the following, salivation-egestion hypothesis for the inoculation of X. fastidiosa during vector feeding. The insect secretes saliva into the plant and then rapidly takes up a mixture of saliva and plant constituents. During turbulent fluid movements in the precibarium, the bacteria may become mechanically and enzymatically dislodged; the mixture is then egested back out through the stylets into plant cells, possibly including xylem vessels. The present study found that proteins extracted from dissected H. vitripennis salivary glands contain several enzyme activities capable of hydrolyzing glycosidic linkages in polysaccharides such as those found in EPS and plant cell walls, based on current information about the structures of those polysaccharides. One of these enzymes, a ß-1,4-endoglucanase (EGase) was enriched in the salivary gland protein extract by subjecting the extract to a few, simple purification steps. The EGase-enriched extract was then used to generate a polyclonal antiserum that was used for immunohistochemical imaging of enzymes in sharpshooter salivary sheaths in grape. Results showed that enzyme-containing gelling saliva is injected into xylem vessels during sharpshooter feeding, in one case being carried by the transpiration stream away from the injection site. Thus, the present study provides support for the salivation-egestion hypothesis.

A pared-down version of 5,10,15,20-tetra(N-methylpyridinium-4-yl)porphyrin intercalates into B-form DNA regardless of base composition: binding studies of tri(N-methylpyridinium-4-yl)porphyrins.

Positively charged N-methylpyridinium-4-yl substituents promote the binding of a porphyrin to DNA, but they also impose steric constraints. To clarify when intercalative binding is most feasible, this report describes syntheses and binding studies of two tricationic ligands: 5,10,15-tri(N-methylpyridinium-4-yl)porphyrin (H2Tri4) and 5-methyl-10,15,20-tri(N-methylpyridinium-4-yl)porphyrin (H2MeTri4). Techniques used to characterize the binding interactions include viscometry and spectroscopic studies of the absorption, emission, and circular dichroism. The striking observation is that intercalation is the only detectable binding motif when the trisubstituted porphyrin H2Tri4 combines with [poly(dA-dT)]2, [poly(dG-dC)]2, or salmon testes DNA. H2Tri4 is, however, a limiting case. Parallel studies of H2MeTri4 and the copper(II) derivative Cu(MeTri4) reveal that external binding to [poly(dA-dT)]2 becomes important when a fourth meso substituent is present, even one as small as the methyl group. Intercalation of H2Tri4 is sterically feasible because two N-methylpyridinium-4-yl substituents can reside in the major groove, though the charge alignment is not optimal. However, the presence of the fourth substituent on H2MeTri4 further destabilizes the intercalated form, and external binding becomes competitive for a flexible host like [poly(dA-dT)]2.

(3R,4S)-4-(2,4,5-Trifluorophenyl)-pyrrolidin-3-ylamine inhibitors of dipeptidyl peptidase IV: synthesis, in vitro, in vivo, and X-ray crystallographic characterization.

A series of pyrrolidine based inhibitors of dipeptidyl peptidase IV were developed from a high throughput screening hit for the treatment of type 2 diabetes. Potency, selectivity, and pharmacokinetic properties were optimized resulting in the identification of a pre-clinical candidate for further profiling.

Acoustic properties of humpback whale songs.

A vertical array of five hydrophones was used to measure the acoustic field in the vertical plane of singing humpback whales. Once a singer was located, two swimmers with snorkel gear were deployed to determine the orientation of the whale and position the boat so that the array could be deployed in front of the whale at a minimum standoff distance of at least 10 m. The spacing of the hydrophones was 7 m with the deepest hydrophone deployed at a depth of 35 m. An eight-channel TASCAM recorder with a bandwidth of 24 kHz was used to record the hydrophone signals. The location (distance and depth) of the singer was determined by computing the time of arrival differences between the hydrophone signals. The maximum source level varied between individual units in a song, with values between 151 and 173 dB re 1 microPa. One of the purposes of this study was to estimate potential sound exposure of nearby conspecifics. The acoustic field determined by considering the relative intensity of higher frequency harmonics in the signals indicated that the sounds are projected in the horizontal direction despite the singer being canted head downward anywhere from about 25 degrees to 90 degrees. High-frequency harmonics extended beyond 24 kHz, suggesting that humpback whales may have an upper frequency limit of hearing as high as 24 kHz.

New fluorinated pyrrolidine and azetidine amides as dipeptidyl peptidase IV inhibitors.

Cyclohexylglycine amides of various fluorinated pyrrolidines and azetidines were prepared and tested for activity against dipeptidyl peptidase IV and in vivo in the KK mouse model of type 2 diabetes. The tetrafluoropyrrolidide, cis-3,4-difluoropyrrolidide and the fluorinated azetidides displayed unexpectedly strong activity.

Glycemic control in mice with targeted disruption of the glucagon receptor gene.

The action of glucagon in the liver is mediated by G-coupled receptors. To examine the role of glucagon in glucose homeostasis, we have generated mice in which the glucagon receptor was inactivated (GR(-/-) mice). Blood glucose levels were somewhat reduced in GR(-/-) mice relative to wild type, in both the fed and fasted state. Plasma insulin levels were not significantly affected. There was no significant effect on fasting plasma cholesterol or triglyceride levels associated with deletion of the glucagon receptor. Glucose tolerance, as assessed by an oral glucose tolerance test, improved. Plasma glucagon levels were strikingly elevated in both fed and fasted animals. Despite a total absence of glucagon receptors, these animals maintained near-normal glycemia and normal lipidemia, in the presence of circulating glucagon concentrations that were elevated by two orders of magnitude.