Design and Synthesis of Metabolically Stable tRNA Synthetase Inhibitors Derived from Cladosporin.

Selective and specific inhibitors of Plasmodium falciparum lysyl-tRNA synthetase represent promising therapeutic antimalarial avenues. Cladosporin was identified as a potent P. falciparum lysyl-tRNA synthetase inhibitor, with an activity against parasite lysyl-tRNA synthetase >100-fold more potent than that of the activity registered against the human enzyme. Despite its compelling activity, cladosporin exhibits poor oral bioavailability; a critical requirement for antimalarial drugs. Thus, the quest to develop metabolically stable cladosporin-derived analogues, while retaining similar selectivity and potency to that of the natural compound, has begun. Chemogenomic profiling of a designed library allowed an entirely innovative structure-activity relationship study to be initiated; this shed light on structural evidence of a privileged scaffold with a unique activity against tRNA synthetases.

Decatransin, a new natural product inhibiting protein translocation at the Sec61/SecYEG translocon.

A new cyclic decadepsipeptide was isolated from Chaetosphaeria tulasneorum with potent bioactivity on mammalian and yeast cells. Chemogenomic profiling in S. cerevisiae indicated that the Sec61 translocon complex, the machinery for protein translocation and membrane insertion at the endoplasmic reticulum, is the target. The profiles were similar to those of cyclic heptadepsipeptides of a distinct chemotype (including HUN-7293 and cotransin) that had previously been shown to inhibit cotranslational translocation at the mammalian Sec61 translocon. Unbiased, genome-wide mutagenesis followed by full-genome sequencing in both fungal and mammalian cells identified dominant mutations in Sec61p (yeast) or Sec61α1 (mammals) that conferred resistance. Most, but not all, of these mutations affected inhibition by both chemotypes, despite an absence of structural similarity. Biochemical analysis confirmed inhibition of protein translocation into the endoplasmic reticulum of both co- and post-translationally translocated substrates by both chemotypes, demonstrating a mechanism independent of a translating ribosome. Most interestingly, both chemotypes were found to also inhibit SecYEG, the bacterial Sec61 translocon homolog. We suggest 'decatransin' as the name for this new decadepsipeptide translocation inhibitor.

Nannocystin†A: an Elongation Factor 1 Inhibitor from Myxobacteria with Differential Anti-Cancer Properties.

Cultivation of myxobacteria of the Nannocystis genus led to the isolation and structure elucidation of a class of novel cyclic lactone inhibitors of elongation factor 1. Whole genome sequence analysis and annotation enabled identification of the putative biosynthetic cluster and synthesis process. In biological assays the compounds displayed anti-fungal and cytotoxic activity. Combined genetic and proteomic approaches identified the eukaryotic translation elongation factor 1α (EF-1α) as the primary target for this compound class. Nannocystin A (1) displayed differential activity across various cancer cell lines and EEF1A1 expression levels appear to be the main differentiating factor. Biochemical and genetic evidence support an overlapping binding site of 1 with the anti-cancer compound didemnin B on EF-1α. This myxobacterial chemotype thus offers an interesting starting point for further investigations of the potential of therapeutics targeting elongation factor 1.

Identification and evaluation of novel acetolactate synthase inhibitors as antifungal agents.

High-throughput phenotypic screening against the yeast Saccharomyces cerevisiae revealed a series of triazolopyrimidine-sulfonamide compounds with broad-spectrum antifungal activity, no significant cytotoxicity, and low protein binding. To elucidate the target of this series, we have applied a chemogenomic profiling approach using the S. cerevisiae deletion collection. All compounds of the series yielded highly similar profiles that suggested acetolactate synthase (Ilv2p, which catalyzes the first common step in branched-chain amino acid biosynthesis) as a possible target. The high correlation with profiles of known Ilv2p inhibitors like chlorimuron-ethyl provided further evidence for a similar mechanism of action. Genome-wide mutagenesis in S. cerevisiae identified 13 resistant clones with 3 different mutations in the catalytic subunit of acetolactate synthase that also conferred cross-resistance to established Ilv2p inhibitors. Mapping of the mutations into the published Ilv2p crystal structure outlined the chlorimuron-ethyl binding cavity, and it was possible to dock the triazolopyrimidine-sulfonamide compound into this pocket in silico. However, fungal growth inhibition could be bypassed through supplementation with exogenous branched-chain amino acids or by the addition of serum to the medium in all of the fungal organisms tested except for Aspergillus fumigatus. Thus, these data support the identification of the triazolopyrimidine-sulfonamide compounds as inhibitors of acetolactate synthase but suggest that targeting may be compromised due to the possibility of nutrient bypass in vivo.

Idiopathic brachial plexus neuritis after laparoscopic treatment of endometriosis: a complication that may mimic position-related brachial plexus injury.

We report the case of a 37-year-old woman who developed idiopathic brachial plexus neuritis, also referred to as Parsonage-Turner syndrome, after laparoscopic excision of endometriosis. The differential diagnosis between this non-position-related neuritis and brachial plexus injury is discussed. The aim of this report was to raise awareness on this distressing postoperative complication.

Allinside Anatomic Arthroscopic (3A) Reconstruction of Irreparable TFCC Tear.

Background In recent years, new arthroscopic techniques have been introduced to address the irreparable tears of the triangular fibrocartilage complex (TFCC) (Palmer type 1B, Atzei class 4) by replicating the standard Adams-Berger procedure. These techniques, however, show the same limitations of the open procedure in relation to the anatomically defective location of the radial origins of the radioulnar ligaments (RUL) and the risk of neurovascular and/or tendon injury. Aiming to improve the quality of reconstruction and reduce surgical morbidity, a novel arthroscopic technique was developed, with the advantages of reproducing the anatomical origins of the RUL ligaments and providing all-inside tendon graft (TG) deployment and fixation. Description of Technique The Allinside anatomic arthroscopic (3A) technique is indicated for TG reconstruction of irreparable TFCC tears in the absence of distal radioulnar joint (DRUJ) arthritis. Standard wrist arthroscopy portals are used. A small incision in the radial metaphyseal area and arthroscopic control are required to set a Wrist Drill Guide and create two converging tunnels, whose openings are at the radial anatomical origins of the RUL. An ulnar tunnel is drilled at the fovea from inside-out via the 6U portal. A 3-mm tendon strip, from the palmaris longus or extensor carpi radialis brevis, is woven through the tunnels and then secured into the ulnar tunnel with an interference screw. Postoperative immobilization with restricted forearm rotation is discontinued at 5 weeks, and then postoperative rehabilitation is started. Patients and Methods The 3A technique was applied on 5 patients (2 females and 3 males), with an average age 42 years. DRUJ stability, range of motion (ROM), pain (0-10 visual analogue scale [VAS]), grip strength, modified Mayo wrist score (MMWS), and patient satisfaction were used for evaluation before surgery and at follow-up. Results No intraoperative or early complications were registered. At a mean follow-up of 26 months, DRUJ was stable in all patients, which recovered 99% ROM. Pain VAS decreased from 7 to 0.6. Grip strength increased from 38 to 48.8 Kgs. There were 4 excellent results and 1 good result on MMWS. All patient showed high satisfaction. Conclusions Although the 3A technique requires dedicated instrumentation and arthroscopic expertise, it takes advantage of improved intra-articular vision and minimized surgical trauma to reduce the risk of complications and obtain promising functional results.

Anterior approach to laparoscopic uterine artery ligation.

Herein is described an anterior approach to uterine artery ligation during laparoscopic myomectomy and total laparoscopic hysterectomy. The anterior leaf of the broad ligament is opened and the uterine artery is clipped lateral to its crossing over the ureter. Outcome measures were completion of the procedure laparoscopically and the need for transfusion postoperatively. Thirty-eight myomectomies and 28 difficult total laparoscopic hysterectomies (primarily uteri with large myomas) were performed, with 1 conversion to laparotomy during myomectomy and 1 during hysterectomy, and 1 transfusion after total laparoscopic hysterectomy. The anterior approach to uterine artery ligation is an alternative method for treatment of uterine artery occlusion during laparoscopic myomectomy or hysterectomy performed to treat large myomas.

Jawsamycin exhibits in vivo antifungal properties by inhibiting Spt14/Gpi3-mediated biosynthesis of glycosylphosphatidylinositol.

Biosynthesis of glycosylphosphatidylinositol (GPI) is required for anchoring proteins to the plasma membrane, and is essential for the integrity of the fungal cell wall. Here, we use a reporter gene-based screen in Saccharomyces cerevisiae for the discovery of antifungal inhibitors of GPI-anchoring of proteins, and identify the oligocyclopropyl-containing natural product jawsamycin (FR-900848) as a potent hit. The compound targets the catalytic subunit Spt14 (also referred to as Gpi3) of the fungal UDP-glycosyltransferase, the first step in GPI biosynthesis, with good selectivity over the human functional homolog PIG-A. Jawsamycin displays antifungal activity in vitro against several pathogenic fungi including Mucorales, and in vivo in a mouse model of invasive pulmonary mucormycosis due to Rhyzopus delemar infection. Our results provide a starting point for the development of Spt14 inhibitors for treatment of invasive fungal infections.

Author Correction: Jawsamycin exhibits in vivo antifungal properties by inhibiting Spt14/Gpi3-mediated biosynthesis of glycosylphosphatidylinositol.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

A randomized controlled clinical trial of 2295 ultrasound-guided embryo transfers.

BACKGROUND: We wanted to test the hypothesis that using abdominal ultrasound at the time of embryo transfer to guide replacement, improved pregnancy rates by at least 5%. METHODS: An RCT in a large assisted conception unit. A pilot study and power calculation suggested that at least 2000 embryo transfers were required to demonstrate a difference of 5%, for a test with 80% power and Type 1 error 0.05. Randomization, data entry and analysis were arranged independently. Randomization was stratified for age and fresh/frozen embryo transfer. Analysis was by intention to treat. RESULTS: There was no difference in clinical pregnancy or live birth rates between the two groups. The clinical pregnancy rate for ultrasound-guided embryo transfer was 22% and for non-ultrasound-guided embryo transfer was 23% (odds ratio: 0.96; 95% confidence interval: 0.79-1.18). CONCLUSIONS: We set out to determine whether ultrasound-guided embryo transfer improved clinical pregnancy rates and live birth rates in assisted conception. We used an appropriately powered RCT design. We did not demonstrate a difference. This outcome is at odds with the UKs National Institute of Clinical Excellence recommendations for fertility treatment (Fertility Assessment and Treatment for People with Fertility Problems. London, UK: RCOG Press, 2004, 112.) which used a meta-analysis of four smaller trials (range 362-800 patients, totalling 2051 embryo transfers) to conclude that ultrasound should be offered. We suggest that the current Cochrane review should be updated with data from our trial and recommend that consideration is given to accounting for heterogeneity between the included trials.

Target Identification and Mechanism of Action of Picolinamide and Benzamide Chemotypes with Antifungal Properties.

Invasive fungal infections are accompanied by high mortality rates that range up to 90%. At present, only three different compound classes are available for use in the clinic, and these often suffer from low bioavailability, toxicity, and drug resistance. These issues emphasize an urgent need for novel antifungal agents. Herein, we report the identification of chemically versatile benzamide and picolinamide scaffolds with antifungal properties. Chemogenomic profiling and biochemical assays with purified protein identified Sec14p, the major phosphatidylinositol/phosphatidylcholine transfer protein in Saccharomyces cerevisiae, as the sole essential target for these compounds. A functional variomics screen identified resistance-conferring residues that localized to the lipid-binding pocket of Sec14p. Determination of the X-ray co-crystal structure of a Sec14p-compound complex confirmed binding in this cavity and rationalized both the resistance-conferring residues and the observed structure-activity relationships. Taken together, these findings open new avenues for rational compound optimization and development of novel antifungal agents.

Infertility after fertility-preserving surgery for cervical carcinoma: the next challenge for reproductive medicine?

Radical trachelectomy is an operation developed as an alternative to radical hysterectomy for patients with small-volume, early stage cervical cancer, who wish to retain their fertility. The body of the uterus is left in place, so that future pregnancies can occur. Patients who have undergone radical trachelectomy may face problems conceiving naturally and may request assisted conception. This article explains the operation and the difficulties that those working in reproductive medicine may face.

The Natural Product Cavinafungin Selectively Interferes with Zika and Dengue Virus Replication by Inhibition of the Host Signal Peptidase.

Flavivirus infections by Zika and dengue virus impose a significant global healthcare threat with no US Food and Drug Administration (FDA)-approved vaccination or specific antiviral treatment available. Here, we present the discovery of an anti-flaviviral natural product named cavinafungin. Cavinafungin is a potent and selectively active compound against Zika and all four dengue virus serotypes. Unbiased, genome-wide genomic profiling in human cells using a novel CRISPR/Cas9 protocol identified the endoplasmic-reticulum-localized signal peptidase as the efficacy target of cavinafungin. Orthogonal profiling in S. cerevisiae followed by the selection of resistant mutants pinpointed the catalytic subunit of the signal peptidase SEC11 as the evolutionary conserved target. Biochemical analysis confirmed a rapid block of signal sequence cleavage of both host and viral proteins by cavinafungin. This study provides an effective compound against the eukaryotic signal peptidase and independent confirmation of the recently identified critical role of the signal peptidase in the replicative cycle of flaviviruses.

Advantages and Challenges of Phenotypic Screens: The Identification of Two Novel Antifungal Geranylgeranyltransferase I Inhibitors.

Phenotypic screens are effective starting points to identify compounds with desirable activities. To find novel antifungals, we conducted a phenotypic screen in Saccharomyces cerevisiae and identified two discrete scaffolds with good growth inhibitory characteristics. Lack of broad-spectrum activity against pathogenic fungi called for directed chemical compound optimization requiring knowledge of the molecular target. Chemogenomic profiling identified effects on geranylgeranyltransferase I (GGTase I), an essential enzyme that prenylates proteins involved in cell signaling, such as Cdc42p and Rho1p. Selection of resistant mutants against both compounds confirmed the target hypothesis and enabled mapping of the compound binding site to the substrate binding pocket. Differential resistance-conferring mutations and selective substrate competition demonstrate distinct binding modes for the two chemotypes. Exchange of the S. cerevisiae GGTase I subunits with those of Candida albicans resulted in an absence of growth inhibition for both compounds, thus confirming the identified target as well as the narrow antifungal spectrum of activity. This prenylation pathway is reported to be nonessential in pathogenic species and challenges the therapeutic value of these leads while demonstrating the importance of an integrated target identification platform following a phenotypic screen.

FR171456 is a specific inhibitor of mammalian NSDHL and yeast Erg26p.

FR171456 is a natural product with cholesterol-lowering properties in animal models, but its molecular target is unknown, which hinders further drug development. Here we show that FR171456 specifically targets the sterol-4-alpha-carboxylate-3-dehydrogenase (Saccharomyces cerevisiae--Erg26p, Homo sapiens--NSDHL (NAD(P) dependent steroid dehydrogenase-like)), an essential enzyme in the ergosterol/cholesterol biosynthesis pathway. FR171456 significantly alters the levels of cholesterol pathway intermediates in human and yeast cells. Genome-wide yeast haploinsufficiency profiling experiments highlight the erg26/ERG26 strain, and multiple mutations in ERG26 confer resistance to FR171456 in growth and enzyme assays. Some of these ERG26 mutations likely alter Erg26 binding to FR171456, based on a model of Erg26. Finally, we show that FR171456 inhibits an artificial Hepatitis C viral replicon, and has broad antifungal activity, suggesting potential additional utility as an anti-infective. The discovery of the target and binding site of FR171456 within the target will aid further development of this compound.

A potential new use for gonadotropin-releasing hormone antagonists.

OBJECTIVE: To describe a potential new use of gonadotropin-releasing hormone (GnRH) antagonists. DESIGN: Case report. SETTING: Assisted conception unit at a teaching hospital in the United Kingdom. PATIENT(S): A 37-year-old woman undergoing in vitro fertilization (IVF) who accidentally stopped using GnRH agonists after starting ovarian stimulation. INTERVENTION(S): A GnRH antagonist was used to avoid a luteinizing hormone (LH) surge and hence "rescue" the cycle. RESULT(S): Successful oocyte retrieval was carried out, two embryos transferred, and a viable twin pregnancy ensued. CONCLUSION(S): This may be a new indication for the use of GnRH antagonists.

Perforation with the GyneFix intrauterine implant: is there a common factor?

This report describes an asymptomatic perforation with the GyneFix intrauterine contraceptive implant. A review of all other reports of this complication has been performed. Analysis of these reports suggests prolonged amenorrhoea secondary to continuous progestogen use as a possible common predisposing factor.

Retrograde ejaculation and male infertility.

Incompetence of the internal urethral sphincter causes semen to pass into the bladder. Infertility can be successfully treated by restoring normal ejaculation or by sperm retrieval techniques.

High-resolution chemical dissection of a model eukaryote reveals targets, pathways and gene functions.

Due to evolutionary conservation of biology, experimental knowledge captured from genetic studies in eukaryotic model organisms provides insight into human cellular pathways and ultimately physiology. Yeast chemogenomic profiling is a powerful approach for annotating cellular responses to small molecules. Using an optimized platform, we provide the relative sensitivities of the heterozygous and homozygous deletion collections for nearly 1800 biologically active compounds. The data quality enables unique insights into pathways that are sensitive and resistant to a given perturbation, as demonstrated with both known and novel compounds. We present examples of novel compounds that inhibit the therapeutically relevant fatty acid synthase and desaturase (Fas1p and Ole1p), and demonstrate how the individual profiles facilitate hypothesis-driven experiments to delineate compound mechanism of action. Importantly, the scale and diversity of tested compounds yields a dataset where the number of modulated pathways approaches saturation. This resource can be used to map novel biological connections, and also identify functions for unannotated genes. We validated hypotheses generated by global two-way hierarchical clustering of profiles for (i) novel compounds with a similar mechanism of action acting upon microtubules or vacuolar ATPases, and (ii) an un-annotated ORF, YIL060w, that plays a role in respiration in the mitochondria. Finally, we identify and characterize background mutations in the widely used yeast deletion collection which should improve the interpretation of past and future screens throughout the community. This comprehensive resource of cellular responses enables the expansion of our understanding of eukaryotic pathway biology.