University of Washington - PK/PD modeling for anti-Shigella drug candidates
Start : September 2017 | Status : Active
Dr. Samuel Arnold and Ms. McCloskey will focus their research on the setting up of an animal model of Shigella for assessing antibiotic efficacy and the integration of in vitro and in vivo data to generate a PBPK/PD model to enable the identification of novel anti-Shigella drug candidates. Samuel Arnold obtained his PhD in pharmaceutics from the University of Washington School of Pharmacy under the guidance of Dr. Nina Isoherranen. He has extensive background in pharmaceutical sciences including enzymology, pharmacology and clinical pharmacokinetics. He has recently contributed to the identification of gastrointestinal drug exposure as an important driver of anti-cryptosporidium drug efficacy.
Molly McCloskey graduated with a Bachelor of Science in Biology from Saint Vincent College, Latrobe, Pennsylvania. Since then, she has studied cellular architecture and the molecular components involved in single cell wound healing. She currently works in the Van Voorhis lab at the University of Washington, working on developing therapies for cryptosporidiosis and aiding in research of other infectious diseases.
The sponsor: University of Washington
Foundation funding: The Foundation is providing £199,874 in support.
GSK’s contribution: GSK will contribute its scientific expertise including DMPK support on lead drug candidates and access to PBPK/PD modeling resources.
Project Description: The project focuses on drug discovery for Shigella. Main challenges in development of anti-shigella drugs are the lack of suitable animal models to evaluate compounds and the lack of information on PK/PD to anticipate in vivo efficacy and human dose.
The first step in this project will be to test if the shigellosis B6 mouse model or other murine alternatives are suitable to evaluate antibiotics. Based on the localization of Shigella to the large intestine and the need to deliver antibiotics in GI tract, previous experience with PBPK-PD models to predict in vivo drug efficacy for anti-cryptosporidium drugs will be applied to predict in vivo efficacy of anti-Shigella compounds.
University of Melbourne - High throughput screening to identify selective proteasome inhibitors as new antimalarials with a novel mode of action
Start : May 2017 | Status : Active
Dr. Stanley Xie is a postdoctoral researcher at the University of Melbourne, working under the supervision of Dr. Leann Tilley. He has extensive experience studying the P. falciparum proteasome and the mechanisms of action of and resistance to artemisinins. He will focus his research on identification and characterization ofnew hits acting through the P. falciparum proteasome.
The sponsor: University of Melbourne
Foundation funding: The Foundation is providing £198.239 in support.
GSK’s contribution: GSK will support the project with its enzymology and high throughput screening platforms and contribute with its past experience working on the P. falciparum Ubiquitin Proteasome System. Additionally, GSK will also provide access to Biosafety Level 3 facilities and to GSK´s collection of proprietary compounds.
Project Description: Current antimalarial control is highly dependent on Artemisinin-based Combination Therapies (ACTs), which makes the emergence of artemisinin (ART) resistance extremely concerning. This situation highlights the need to identify new drugs targeting different mechanisms in the parasite. The proteasome is a validated target for malaria. Inhibitors of the proteasome show parasiticidal activity against both ART sensitive and resistant parasites, and are active both against sexual and asexual intraerythroctyic stages, as well as liver stages. Moreover, the Leann Tilley lab has demonstrated that inhibitors of the proteasome strongly synergize ART-mediated killing of P. falciparum, being also suitable for combination therapies.
The objective of this Open Lab project is to undertake a screening campaign to identify P. falciparum-specific proteasome inhibitors, thereby avoiding any toxicity associated with inhibition of the human proteasome. An extensive compound characterization will be performed, determining the parasitological profile and the mechanism of action applying tools developed in parallel during the project.
London School of Hygiene and Tropical Medicine - Optimization of imidazopyridine and thiazole scaffolds targeting plasmodial kinases to generate a fast killing compound to treat malaria infection and block transmission
Start : January 2017 | Status : Active
The scientists: Dr Alexios Matralis and Adnan Malik will work in the optimization of imidazopyridine and thiazole scaffolds targeting plasmodial kinases. Both researchers are medicinal/organic chemists with post-doctoral experience. Their main role will be the design, synthesis and characterization of the new compounds as well as the proposal of new ideas based on the acquired knowledge.
The sponsor: London School of Hygiene & Tropical Medicine
Foundation funding: The Foundation is providing £107,140 in support.
GSK’s contribution: GSK will contribute its experience in phenotypic programs, medchem expertise, parasitology, in vitro assays, safety, and its in vivo humanized mouse model.
Project Description: Starting from a set of compounds prepared by D. Baker’s group that showed activity in GSK phenotypic and dual gamete formation assays on top of its activity against P. falciparum cGMP-dependent protein kinase (PfPKG), this open lab will focus on improve the physchem profile of these families, increase their potency in the phenotypic/dual gamete formation assays, abolish toxicity issues, and gain knowledge of their in vitro killing profile in order to focus only in fast killing compounds. The aim of the project is to deliver compounds active in vivo in the P. falciparum mouse model, with physicochemical properties that allow developability and adequate safety profile.
University of Alabama at Birmingham - Self-poisoning of Mycobacterium tuberculosis by inhibiting siderophore secretion
Start : July 2016 | Status : Active
Dr. Avishek Mitra, Bjorn Sunde and Prof. Michael Niederweis will focus their research on the identification of small molecules that kill Mycobacterium tuberculosis by inhibiting siderophore efflux. Dr. Mitra is a postdoctoral researcher working on iron acquisition by M. tuberculosis in the laboratory of Prof. Niederweis in the Department of Microbiology at the University of Alabama at Birmingham. Bjorn Sunde is a research assistant with experience in performing high-throughput screening assays in Biosafety Level 3 laboratories.
The sponsor: University of Alabama at Birmingham, Department of Microbiology
Foundation funding: The Foundation is providing £213,119 in support.
GSK’s contribution: GSK will provide access to biosafety level 3 and high-throughput screening facilities, microbiology and drug discovery expertise as well as full access to antimycobacterial compound sets
Project Description: Iron is an essential nutrient for M. tuberculosis which can acquire iron from heme and from its siderophores, mycobactin and carboxymycobactin. This project is based on the surprising finding that blocking siderophore secretion reduces the virulence of Mtb in mice by 10,000-fold. This is one of the strongest virulence defects observed for any Mtb mutant, probably due to the intracellular accumulation of siderophores. Externally added siderophores accumulate in the Mtb secretion mutant and are toxic at submicromolar concentrations. Importantly, this toxicity cannot be overcome by other iron sources such as heme in contrast to Mtb mutants deficient in siderophore biosynthesis. Since siderophore secretion spans both membranes, inhibitors might target this pathway from the outside of the cell and, thereby, might avoid the outer membrane permeability barrier of Mtb.
We have developed a high-throughput screening assay that has identified inhibitors of Mtb whose activity depends on siderophores. These compounds are not detected in whole cell screens under standard conditions. Thus, siderophore secretion appears to be a valuable target for novel TB drugs that will be exploited in this project.
Structural Genomics Consortium - Identification of small molecule inhibitors targeting plasmodium methyltransferase SET1 and elongation factor 2
Start : March 2016 | Status : Active
Dr. Cynthia Tallant is a Postdoctoral Researcher in the Chemical Biology Unit at the Structural Genomics Consortium (SGC), working under the supervision of Dr. Kilian Huber and Dr. Raymond Hui. She has a PhD in Structural Biology and Enzyme Kinetics and several years of experience as a PostDoc in these areas.
The sponsor: The Structural Genomics Consortium, Structural and Chemical Parasitology lab (Oxford and Toronto).
Foundation funding: The Foundation is providing £160,915 in support, including co-funding from the European Union through its FP7 COFUND programme.
GSK’s contribution: GSK is providing scientific expertise in screening, enzymology, medicinal chemistry, in vitro parasite culture as well as access to Biosafety Level 3 facilities and to GSK´s collection of proprietary compounds.
Project Description: The focus of the project will be the exploration of new antimalarial targets involved in parasite transcriptional regulation, such as the histone methyltransferase (HMT) SET1, and protein biosynthesis pathways controlled by the ribosomal translation elongation factor 2 (eEF2).
A number of histone methyltransferase inhibitors have been shown to inhibit parasite growth in the intraerythrocytic cycle in both P. falciparum and P. vivax ex vivo experiments. Concomitantly, these same compounds were shown to reduce H3K4me3 methylation levels in parasites. Additional genetic studies in P. falciparum showed that some of these genes are essential for the parasite in the asexual blood stage.
Recently, a novel antimalarial compound DDD107498 has been discovered and publicly discosed. This compound has excellent drug-like properties and exhibits a potent activity profile against multiple life-cycle stages of the parasite. Its molecular target has been identified as the translation elongation factor 2 (eEF2) using whole genome sequencing of resistant cell lines treated with DDD107498. This finding nominates PfEF2 as a novel antimalarial target.
Together, the proposal aims to identify chemically diverse compounds targeting these two classes of enzymes, with activity against resistant mutants and inert to the human orthologues.
University of South Florida (USF), WRAIR and NIH - Antimalarial drug discovery targeting pre-erythrocytic stages of Plasmodium falciparum
Start : TBD | Status : Set up ongoing
The scientists: TBD
The sponsor: University of South Florida (USF), WRAIR and NIH.
Foundation funding: The Foundation is providing £352,939 in support.
GSK’s contribution: GSK to share access to all generated data and provide access/use of compounds identified from the screen for further evaluation beyond the scope of this proposal. The Tres Cantos unit will provide in kind assay consumables and resources equivalent to two full-time personnel who will assist with gametocyte production, mosquito rearing and infections, dissections, imaging, data analysis, and support.
Project Description: This project offers a major advance in antimalarial drug discovery by targeting pre-erythrocytic stages to block malaria infection. We have developed an innovative P. falciparum in vitro liver assay to evaluate drug toxicity and inhibitory efficacy of critical early phase of malaria infection in human hepatocytes. Consequently, this project can efficiently evaluate drug inhibition of the complete liver stage of the malaria life cycle. Central to this new screening strategy is a G384 microplate culture system using primary human hepatocytes (PHHs)(1) with modified P. falciparum sporozoite isolation procedures (2, 3). To enhance identification of the best lead compounds we will use quantitative functional assays of sporozoite entry into and egress from human hepatocytes along with transmission-blocking assays for mosquito infections. In developing our assays, we identified key microenvironmental triggers of infectivity that downstream can be used to elucidate target specificity and mechanisms of action.
Altogether we provide a comprehensive new screening strategy for antimalaria drugs to block infection.
Sanger Institute - A chemogenomic overexpression screen to identify malaria liver stage targets
Start : TBD | Status : Set up ongoing
The scientists: TBD
The sponsor: Sanger Institute.
Foundation funding: The Foundation is providing £169,475 in support.
GSK’s contribution: At early stages of the project GSK will provide significant input in shortlisting compounds for target identification and provide panels of compounds, as well as collaboratively prioritising targets of interest to be included in the screening panel of PACs. GSK will as well perform chemical re-synthesis of compounds if required. Later they will provide chemo-informatics expertise for data analysis. Targets for validation will be jointly decided. At a late stage of the project, targets with potential for cellular or recombinant enzyme screening will be selected. If compounds have the appropriate characteristics (solubility, DMPK properties, etc) validation work in mouse models will be done at Tres Cantos.
Project Description: There is a widely recognised need for antimalarial drugs that target liver stages (1) but the paucity of suitable liver stage culture systems for human Plasmodium species has so far limited their development. Screening systems are now improving, and cellular screens have identified compounds that selectively kill this parasite stage, with the expectation that such compounds would have prophylactic potential. However, current screening assays have limited throughput. Identifying targets would allow target-based screens in a high-throughput format and explore millions of compounds. Because of the culture systems target ID cannot be achieved through conventional resistance selection approaches used so successfully with blood stage targets (2). In addition, the inefficiency (in the case of P. falciparum) or impossibility (in the case of P. vivax) of experimental genetics has so far prevented rational, target-led approaches to develop liver-active compounds. The strategy we propose here will therefore be potentially paradigm shifting, since it enables systematic screens for targets of liver-specific compounds for the first time.
Genome-scale chemical-genetic interaction screens have successfully identified small molecule targets in libraries of diploid yeast (3-4) that carry heterozygous loss-of-function mutations in individual genes, sensitising their carriers to inhibitors of the same target or pathway. For malaria parasites, which are haploid, we here present evidence that chemical-genetic interaction screening can be used to identify targets not only at the blood stage but also in liver stages. Working with P. berghei, a parasite species that is uniquely suited to study liver stage biology in vitro, we have generated tools and methods to increase expression of parasite genes in a controlled and selective manner by introducing extra copies of the part of the genome that encodes them. We have created a library of Plasmodium artificial chromosomes (PACs) that can be transfected efficiently in pools during blood stages and are faithfully inherited through mosquito and liver stages. Our preliminary data show that treating cultured liver stages reproducibly shifts the relative abundance of individual PACs in accordance with known modes of action and modes of resistance, associating targets with compounds in an unbiased manner.
Using this approach, we have defined the parameters for successful chemogenomic screening in liver stages. We propose here to apply the system to screen 24 liver-active compounds against 625 high priority targets. We will then work with GSK to select and follow up on the most interesting new targets by more detailed validation, cellular/recombinant protein assay development and target-based screens, which will be used to discover new chemical series for future development.
Seattle Children’s Research Institute & University of Washington - Identifying and inhibiting M. tuberculosis regulators that influence infection outcome
Start : TBD | Status : Set up ongoing
The scientists: TBD
The sponsor: Seattle Children’s Research Institute.
Foundation funding: TBD – just WP4 funded
GSK’s contribution: In vivo and in vitro screening capacity available in Tres Cantos. Small molecule library for screening. Housing and lab space for one visiting scientist.
Project Description: The goals of this project is to: 1) assess which M. tuberculosis (MTB) transcription factors (TFs) and regulons are important for survival during host infection; 2) define conditions under which these TFs are activated or deactivated; and 3) identify small molecules that inhibit their activity. To address these questions, we will: 1) screen for TFs that convey altered viability during infection when induced or disrupted in the chronic murine infection model; 2) develop screen based on reporter strains that will indicate TF-specific promoter activity; and 3) apply screen to a panel of conditions (including chemical inhibitors) to identify conditions that activate and deactivate individual TFs. The proposed approach is complementary to screens that have been run to date, as compounds with TF activity may be missed if MIC is the primary assay. TFs are a desirable target because their behavior is often switch-like, so successful targeting may be achieved with limited dosages and associated toxicities. Additionally, the known MTB transcription factors are structurally dissimilar to human TFs.
University of Washington - High Throughput Screening for Inhibitors of Shigella Virulence Determinants
Start : TBD | Status : Set up ongoing
The scientists: TBD
The sponsor: University of Washington.
Foundation funding: The Foundation is providing £145,204 in support.
GSK’s contribution: Technical assistance with the inhibitor screen including help with instruments and software. Access to GSK’s small molecule libraries. Extensive communication and advice regarding screen design, execution, troubleshooting, and compound identification.
Project Description: The primary goal of this proposed project is to test the hypothesis that small molecule inhibitors of Shigella transcription factors can promote the rapid resolution of infection. Previously, data collected from an in vivo transposon library screen (TN-Seq) using a guinea pig model of shigellosis was performed to provide a global view of genes and pathways that are critical for Shigella to survive and compete within the host.
Disrupting the expression of these crucial genes and pathways with small molecule inhibitors is expected to result in severe defects in Shigella’s ability to colonize the host and cause disease. The proposed project will use high throughput assays to screen compound libraries for inhibition of pathways deemed to be essential for Shigella to survive in the host. Identified hits will be validated and tested for their capacity to functionally alter the course of Shigella infection using established in vivo models. If successful, this strategy could act as a blueprint for developing new drugs that target essential survival pathways in microorganisms, leading to an entire new class of treatments against infectious diseases.
University of California - Hit-to-Lead Development of the Kalihinol Scaffold for Malaria Treatment
Start : TBD | Status : Set up ongoing
The scientists: TBD
The sponsor: University of California.
Foundation funding: The Foundation is providing £172,190 in support.
GSK’s contribution: The in-kind contributions from GSK will involve the characterization of simplified kalihinol analogues for their efficacy, safety, pharmacodynamics, and pharmacokinetics properties, initially to ensure that this series of compounds is as promising as our initial data suggest. In the medium term, further evaluations of these types will guide a medicinal chemistry effort for hit-to-lead development.
Project Description: The ultimate goal of this collaborative research program is to identify antimalarial clinical candidates among analogues of the kalihinol family of isocyanoterpenes (Figure 1), an understudied class of natural products with potent activity against Plasmodium falciparum, the causative agent of the deadliest form of human malaria. Preliminary data generated in our laboratories support the premise of this research that the kalihinols could be developed as novel antimalarial agents. Our data demonstrate that (i) kalihinol natural products have potent activity against blood stages of both drug-sensitive and drug-resistant P. falciparum strains with IC50 values in the low nanomolar range; (ii) the synthetic route to these compounds has been simplified producing analogues that retain potent antimalarial activity, and there is a chemical plan in place for further synthetic simplification; (iii) the compounds have good HepG2 inhibition data and no major in silico safety alerts, and; (iv) they may exert their antimalarial activity through a novel mode of action. Building upon this body of data, we propose to delve deeply into the structure-activity relationship of these compounds, characterize their in vitro and in vivo efficacy and safety, and unravel their mode of action.
University of Zaragoza - TB antivirulence therapeutics: small molecule inhibitors against M. tuberculosis replication and persistence pathways as novel alternatives to classic antibiotics.
Start : March 2019 | Status : Set up ongoing
The scientists: TBD
The sponsor: University of Zaragoza.
Foundation funding: The Foundation is providing £153,435 in support.
GSK’s contribution: The in-kind contributions from GSK will involve:
- HTS using the GSK chemical library
- Cytotoxicity, solubility, stability, …assays to define the value of identified compounds
- Chemistry support for SAR and compound selection
- Proteomics approaches
- In vivo activity in a mouse model of TB virulence
Project Description: Multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB have alarmingly spread worldwide and make treatment difficult or even impossible. In addition, the one third of the human population latently infected with TB (LTBI) constitutes an enormous reservoir. Antivirulence therapies with small molecules that sabotage bacterial survival in the host may have advantages over traditional antibiotics because it targets factors required for pathogenesis, potentially reducing selection for resistance and limiting collateral damage to the resident microbiota (1, 2).
Our project proposes a novel approach to disarm M. tuberculosis (Mtb), focused on searching antivirulence therapies against transcription factor PhoP as a paradigm regulon essential for Mtb virulence (3, 4). Recently, a small molecule inhibiting a transcription factor has been described to revert antibiotic resistance (5). We propose the construction of a reporter Mtb strain by placing strongly PhoP-regulated promoters (4) upstream GFP which will allow the screening of the complete GSK compound collection. Loss of GFP fluorescence upon treatment, indicative of selective virulence inhibition, can be easily monitored by high-throughput screening. Potential synergies between inhibitors, or between inhibitors and current anti-TB drugs will be assayed. We will confirm whether these compounds are active in macrophage and mouse models of TB and we also plan to assay the selected compounds against representative isolates of Mtb Complex lineages, which reflect the current genetic diversity of TB worldwide.
IBR-CONICET_UNR Instituto de Biología Molecular y Celular de Rosario - Trypanosoma cruzi bromodomains: druggable readers to look out!
Start : March 2019 | Status : Set up ongoing
The scientists: TBD
The sponsor: Seattle Children’s Research Institute & University of Washington
Foundation funding: The Foundation is providing £82,305 in support
GSK’s contribution: GSK will give us access to a library of potential bromodomain inhibitors, as well to humans BRD proteins. On the other hand, GSK will let us introduce us in the field of high/medium throughput screening in which we lack expertise.
Project Description: The discovery of new therapeutic options against Trypanosoma cruzi, the causative agent of Chagas disease stands as a fundamental need, since available drugs have significant toxic side effects and a variable efficacy against the life-threatening symptomatic chronic stage of the disease. Bromodomains are protein modules that bind to acetylated lysine residues. Their interaction with histone proteins suggests their role in interpreting the histone code. However, protein acetylation is not a phenomenon restricted to the nuclear proteins. Bromodomain-containing proteins are often found as components of larger protein complexes with roles in fundamental cellular process including transcription, cell cycle regulation, among others. In 2010 two BET bromodomains ligands were described demonstrating that small molecules could inhibit the bromodomain-acetyl-lysine interaction. These molecules display strong phenotypic effects in a number of cell lines and affect a range of cancers in vivo. Recent reports showed that bromodomain inhibitors affect T. cruzi viability and deregulate the expression of stage-specific proteins in T. brucei. The overall objective of this project is to search for bromodomain inhibitors in T. cruzi, by assaying essentials bromodomains previously established in a collaborative GSK-sponsored research project between Esteban Serra’s and Roberto Docampo’s labs. From this project three bromodomains from T. cruzi were selected as putative targets against Chagas disease.
University of Cambridge - High throughput small molecule screen for drugs that alter the shape of Campylobacter jejuni
Start : TBD | Status : Set up ongoing
The scientists: TBD
The sponsor: University of Cambridge
Foundation funding: The Foundation is providing £118,040 in support
GSK’s contribution: GSK will contribute with high throughput screening expertise to miniaturize the assay. GSK will provide compounds for screening and access to Shigella animal models as well as drug discovery expertise to assess the potential of this approach to deliver a drug for patients.
Project Description: The world faces a major infectious disease challenge that is being made worse by antimicrobial resistance. We need new therapeutic modalities that overcome resistance and that do not affect the natural gastrointestinal flora, which is proven to be essential for gastrointestinal health. We contend that cell shape may be a targetable Achilles heel for enteric bacterial pathogens and has not yet been fully exploited for drug discovery applications. There is evidence that cell shape can affect the virulence of pathogens (e.g. Campylobacter spp. and Salmonella spp.). Through this Open Lab project, this characteristic will be exploited for high-throughput screens against Shigella spp. and other enteric bacteria.
Research Agency of Aragon (ARAID) & University of Zaragoza (UNIZAR) - Predicting optimal dosing schedules and clinical outcomes of beta‐lactams for TB therapy using PKPD and mechanistic models Carbapenem vs. cephem: the beta‐lactam paradigm
Start : April 2018 | Status : Set up ongoing
The scientists: Santiago Ramón y María Pilar Arenaz
The sponsor: Research Agency of Aragon (ARAID) & University of Zaragoza (UNIZAR)
Foundation funding: The Foundation is providing £116,500 in support
GSK’s contribution: GSK’s in kind contributions would be critical for the following: (i) Access to time-lapse microscopy and micro-pumping system to mimic PK profiles; (ii) imaging and analytical modeling software and skills; (iii) access to clinical data for modeling. In addition, based on previous experience (RIFACEPH project), the excellent scientific and personal support provided by GSK scientists would greatly facilitate the successful outcome of this proposal.
Project Description: This proposal aligns and complements with current clinical trials now being explored by GSK DDW clinical partners. It also comes with additional funding that the applicant, Dr. Ramón-García, recently secured from the European Community for a 2-year project to be performed at GSK DDW.
Carbapenems and cephems are beta-lactam (BLMs) antibiotics with different anti-tuberculosis (TB) killing properties and phenotypic responses that might affect therapy design for optimal clinical outcomes (Figure 1). Understanding the pharmacokinetic (PK) and pharmacodynamic (PD) parameters of BLMs alone and in combination with synergistic partners is critical if they are to be used for TB therapy (Figure 2). Similarly, the molecular determinants underlying synergistic interactions of BLMs with synergistic partner drugs are currently unknown. Elucidating the synergistic mode of action of such combinations will allow the design of novel strategies for TB therapy and help counteract the emergence of future resistance.
To answer these questions, time-lapse microscopy, in vitro microbiology assays and transcriptomic studies will be leveraged to provide high quality molecular and pre-clinical data that, through mathematical PKPD modeling based on completed and ongoing GSK DDW BLM-containing TB clinical trials, will inform the design of future human combination trials with BLM components.Campylobacter spp. and Salmonella spp.). Through this Open Lab project, this characteristic will be exploited for high-throughput screens against Shigella spp. and other enteric bacteria.
EMBL- Unravelling new combinatorial therapies against Shigellosis
Start : July 2018 | Status : Active
The scientists: 2 FTE at EMBL
The sponsor: EMBL
Foundation funding: The Foundation is providing £116,800 in support
GSK’s contribution: GSK will provide expertise with high throughput screening set ups and compound screening, as well as with data analysis. GSK will provide compound libraries and drug discovery expertise to assist in the compound selection. Materials for the experimental part performed at GSK will be provided in kind. GSK pharmacologist experts will support this project to unravel the PK/PD of synergistic combinations.
Project Description: Combinatorial treatments provide an untapped, cost-effective source for new antibacterial treatments at a time where new therapies are urgently needed. Here we propose to establish a high-content microscopy platform for systematically screening drug combinations against intracellular Shigella. Shigellosis is one of the leading causes of diarrhea worldwide, with infections being more frequent and deadly in the developing world. The microscopy platform set up will not only facilitate high-throughput screening at the intracellular context of infection, where this pathogen has to be targeted, but will also provide insights into the mechanism-of-action of single drug(s) and the combinatorial treatment by monitoring the stage of infection and the host process(es) they affect. Using this platform, we will evaluate the impact of ~5,000 drug combinations during the course of infection in epithelial cells and macrophages. Strong synergies will be further evaluated in detailed surface response measurements (inhibition and killing curves – intracellularly and extracellularly), resistant and persistent assays. Last, prominent candidates will be moved to animal models and PK/PD measurements.
University of Michigan - Targeting Virulence Regulators as a Novel Approach to Antibiotics for Shigellosis
Start : Nov 2018 | Status : Active
The scientists: Marija Miljkovic
The sponsor: University of Michigan
Foundation funding: The Foundation is providing £81,085 in support
GSK’s contribution: GSK will provide compounds for screening, consumables and expertise to perform the HTS and to select and prioritize the most promising hits. Biology and pharmacology support will be provided as well.
Project Description: Diarrheal diseases, such as shigellosis, are the second leading cause of death in children under five years old. Many strains of Shigella spp. are drug or multi-drug resistant. Genetic knock-out studies of the Shigella virulence pathway controlled by the AraC-family transcription factor VirF (required for infection, cell-to-cell spread and escape from macrophages) show that inactivation of VirF or other virulence factors eliminates, or significantly reduces, pathogenicity. Importantly, expression of virulence factors is not required for Shigella viability; therefore, targeting virulence factors is expected to lower the risk for resistance development in Shigella while not affecting normal, avirulent colonic microbiota. We have identified 5 hits from an HTS of ~150,000 small molecules that inhibit VirF expression of a reporter gene and reduce the invasion efficiency of Shigella in in vitro models of infection. One of these hits blocks VirF binding to DNA. Our goal in this proposal is to identify novel and potent chemical matter that block Shigella virulence to conduct a ‘hit-to-lead” campaign. We will screen compounds from GSK’s 1.7M compound library, perform confirmation and secondary assays probing mechanism of action, PK/Tox and in vitro efficacy. Compounds that inhibit VirF•DNA binding will be co-crystalized with the VirF DNA binding domain to enable a structure-based hit-to-lead campaign.
University of Georgia + Bioaster - Chagas AABLO (Chagas AcylAminoBenzothiazol Lead Optimization)
Start : Janurary 2018 | Status : Active
The scientists: Charlotte Fleau
The sponsor: University of Georgia + Bioaster
Foundation funding: The Foundation is providing £159,226 in support
GSK’s contribution: Chemistry labs for synthesis, purification, structure analysis. Full Profiling of Development pre-Candidate (ADMET2 and early toxicology).
Project Description: T. cruzi is a protozoan parasite that causes Chagas disease, the highest impact infectious disease in Latin America. Although the host immune response is highly effective at controlling T. cruzi, the infection persists in most infected hosts. Previous work between our groups at The University of Georgia (UGA), Sanofi and BIOASTER has identified several Acyl-AminoBenzothiazol (AAB) hits with potent in vitro and in vivo toxicity for T. cruzi. These related hits came from an initial in vitro screen of a ~300,000 small molecule library by the Broad Institute (Pubchem AID: 1885); 171 of the ~3500 in hits with in vitro activity were selected for in vivo screening based upon druglikeness, potential for oral delivery and ease of synthesis and novelty. In a rapid in vivo efficacy assay, 5 of the 171 compounds showed strong activity – 3 of those 5 were in this AAB group. Subsequent in vitro SAR of 240 analogues revealed 3 AAB compounds with IC50 of <80 nM and identified the steps needed to optimize this compound class. Herein we describe the med chem plan for this optimization as well as for identification of the mechanism of action of these compounds. Paired with our unparalleled combination of in vitro and in vivo screening assays, and the prior evidence of in vivo efficacy of this compound class, we have an excellent opportunity to identify one or more compounds capable of providing parasitological cure.
Oxford University - Structural biology and assays enabling β-lactams that target Mycobacteria tuberculosis
Start : July 2017 | Status : Active
The scientists: Jurgen Brem – Mariska de Munnik
The sponsor:Oxford University
Foundation funding: The Foundation is providing £162,000 in support
- Determination of anti Mtb activity in vitro and in vivo. Oxford University does not have the capacity required for this work, therefore a collaboration with GSK TC is essential for the project.
- Supply of compounds for testing in assays and structural evaluation (Note initial work will focus on compounds already available, with focused medicinal chemistry being the subject of a new funding application.)
- Expertise in mechanistic chemistry (including modeling) to be used in inhibitor design possibly coupled to modeling
- Assistance in project management including via frequent (Skype / phone) meetings
- Expertise in identifying routes to pre-clinical and clinical candidates
- A desire to work together to secure future large-scale funding to develop -lactam / analogous compounds to be used for Mtb treatment
- The ability to work collaboratively with Oxford to rapidly follow up breakthrough results on new types of inhibitor.
Project Description: β-Lactams, including penicillins, cephalosporins and carbapenems, remain the most important antibiotics in use for treatment of Gram- and Gram+ bacteria, but their use is compromised by growing resistance, most importantly due to widespread β-lactamase dissemination. Mycobacteria tuberculosis (Mtb) has a higher mortality rate than any other infectious disease; however, β-lactams have traditionally not been effective in Mtb treatment. The paradigm that β-lactams are not useful for treatment of Mtb (including XDR Mtb) is based on the poor cell permeability/stability/oral use of ‘classical’ β-lactams (which poorly penetrate the cell-membrane) and the presence of a genetically encoded β-lactamase (BlaC) in Mtb. This paradigm is now being questioned [1-3], because: (i) Recent clinical trials shows that meropenem combined with amoxicillin–clavulanic acid has potential for treating Mtb; (ii) Carbapenems not only inhibit Mtb D,D-transpeptidases, but can also Mtb inhibit L,D-transpeptidases ; (iii) Clinically used cephalosporins in combination with clavulanic acid manifest synergistic effects in Mtb treatment; (iv) novel cephalosporins with C-2 carboxylate isosters have shown selective activity against non-replicating Mtb . Thus, the timing is right for focused efforts to develop tailored β-lactams for Mtb treatment together BlaC inhibitors, the latter being the initial focus of our proposed work.
Such work will be enabled by contemporary availability of: (i) New types of transpeptidase / β-lactamase inhibitors, including new acylating agents, such as those based on avibactam and lactivicins , and ‘transition state analogues’ e.g. cyclic boronates that display remarkable potency against β-lactamases ; such compounds have potential as transpeptidase inhibitors with very different PK/PD properties compared to classical β-lactams; (ii) Extensive new structural and mechanistic information on β-lactam mode of action and resistance mechanisms has emerged since the classical β-lactams were developed; (iv) New synthetic methodologies enable access to complex densely functionalised rings systems (e.g. functionalized oxapenems) previously unviable due to ‘cost of goods’ issues; (v) Knowledge of (Mtb infected) human cell biology will enable more rational targeting of β-lactams to Mtb in human cells. The focus of this OpenLab project will be structural, screening, and mechanistic work (including involving new inhibitors types) that will enable future medicinal chemistry efforts to enable clinically useful BlaC resistant PBP inhibitors for oral Mtb treatment.
Oxford University Clinical Research Unit - Hit discovery for new antimicrobials against Shigella spp.
Start : April 2017 | Status : Active
The scientists: Andrew Lim – Phat Voong Vinh
The sponsor:Oxford University Clinical Research Unit
Foundation funding: The Foundation is providing £174,038 in support
GSK’s contribution: GSK will provide facilities for HTS and compound collections to be screened. In addition, GSK will provide resources in kind for DMPK and safety profiling of the interesting hits identified.
Project Description: Our ultimate aim is to develop new drugs for the treatment of infections caused by Shigella spp. (a major cause of diarrhea in low-income countries) that work through novel mechanisms of action. Within this open-lab application we aim to carry out the following:
- Phenotypic screening against Shigella sonnei and Shigella flexneri 2a using chemically diverse compound libraries under a variety of conditions aiming, where possible, to mimic physiological conditions
- Screening compound libraries against AMR isolates in the presence of antimicrobials to which they are resistant, aiming to identify compounds that restore antimicrobial activity
- Compound hits will be validated through assay against panels of clinical isolates, including newly emergent MDR strains
- Validated hits will be profiled in various in vitro DMPK assays, such as solubility and metabolic stability. Preliminary safety assessment in silico and in vitro will be additionally performed, as well as hit expansion
Biomedical Primate Research Centre - Optimization of hepatocyte culture to support drug screening for malaria hypnozoites
Start : May 2017 | Status : Active
The scientists: Anke Harupa – Lars Vermaat
The sponsor:Biomedical Primate Research Centre
Foundation funding: The Foundation is providing £141,552 in support
GSK’s contribution: We envisage GSK’s contribution in the field of hepatocyte culture, which will be of great value to the project. The Open Lab scientist will perform part of the hepatocyte culture optimization at GSK facilities, GSK will provide consumables for these periods in kind as well as mentoring from experienced researchers.
Project Description: The BPRC P. cynomolgi in vitro liver stage drug assay, enabling drug screening on developing- and dormant liver stages (hypnozoites), may be biased towards prophylactic compound activity, rather than radical curative activity. The assay is performed with primary rhesus monkey hepatocytes and drug exposure from day 0 to 6 days post sporozoite infection. We are currently developing an assay that may be more predictive for radical curative activity, by applying compound exposure from day 5 to 9 post infection. Primaquine (PQ), the only positive control with known radical curative activity in vivo, has variable activity in the standard assay and no activity in the radical cure type assay. Thus, we are lacking a positive control in the assay. As PQ needs to be metabolized to display anti-hypnozoite activity, it is likely that declining metabolic activity over time of the primary hepatocytes causes this variable activity in the standard assay and absence of activity in the radical cure type assay. We plan to address this by first fully characterizing hepatocytes during culture and in the liver prior to isolation. This includes typical hepatocyte markers as well as the metabolism capacity. We will then apply alternative culture methods and monitor PQ metabolism over time. Finally, we will monitor parasite invasion and growth and PQ anti-parasite activity over time, and adapt culture conditions further to arrive at an optimal radical cure type assay. Once the radical cure assay is optimized, a set of compounds will be screened, using PQ as the positive control, aiming to identify novel compounds with radical cure activity.
Utrecht University - Attacking Shigella by blocking its disease causing Toxin
Start : October 2017 | Status : Active
The scientists: Jie Shi – Torben Heise
The sponsor: University of Utrecht
Foundation funding: The Foundation is providing £152,256 in support.
- Use of premises (space), associated site costs and shared service support
- Lab supplies at GSK
- Pre-clinical development services (in vivo studies, Chem Dev, Pharm Dev)
- Access and support from a “GSK mentor” throughout the duration of the project
- Support from other scientists as project needs.
Project Description: Our approach towards Shigella involves the Shiga toxin as its target. This toxin causes serious disease,and is clearly on the rise in the dominant Shigella species in the developing world. It is an AB5 toxin that binds to multiple copies of a carbohydrate moiety expressed on the cell surface. We intend to design and synthesize the optimal binding moieties for toxin binding. These designs are based on our previously successful rigid spacer design for bridging binding sites and on our approach to inhibit the related Cholera AB5 toxin at picomolar concentrations. The focus is on intercepting the toxin in the blood stream. The Shiga toxin is an excellent target as it should be amenable to very potent inhibition and a demonstration of in vivo susceptibility has already been made. We intend to design and synthesize the compounds in Utrecht (UU) and explore their potency and activity at OL.
University of Georgia - Rapid selection of in vivo active anti-Trypanosoma cruzi compounds
Start : July 2016 | Status : Active
The scientists: Dr. Alba Gigante is an organic/ medicinal chemist by training, with experience working in neglected diseases. Currently she is a Postdoctoral Researcher working with Prof. Rick Tarleton from the University of Georgia. Her primary role in this project is to identify novel phenotypic leads against Trypanosoma cruzi from the TCAKS_CHAGAS set (Tres Cantos Anti Kinetoplastid Set). During her stay in Tres Cantos she will perform analog searches within GSK library for the in vivo active hits as well as the design of convergent synthetic routes for further SAR enrichment.
The sponsor: University of Georgia
Foundation funding: The Foundation is providing £189,705 in support.
GSK’s contribution: GSK will contribute with solid availability for compounds in the TCAKS_CHAGAS set (Tres Cantos Anti Kinetoplastid Set) as well as analogue searching within the GSK collection. GSK will contribute in-kind its drug discovery expertise supporting the design of new analogues as well as completing preliminary compound profiling (in vitro T.cruzi, in vitro ADMET)
Project Description: T. cruzi is a protozoan parasite that causes Chagas disease, the highest impact infectious disease in Latin America. Previous work at Tres Cantos has identified a total of 222 small molecule prioritized according to their potency against T.cruzi, cytotoxicity, and physico-chemical properties, called TCAKS-Chagas. The purpose of this project is to determine which among these prioritized in vitro-active compounds also has substantial in vivo activity on T. cruzi, and thus promise as a hit for lead compound development.
The investigators from University of Georgia, led by Prof. Rick L. Tarleton, have developed a facile and rapid assay that makes use of transgenic T. cruzi lines expressing fluorescent proteins, which allows imaging the establishment and expansion of these tagged parasites after a single administration of compound, and hence determine in vivo efficacy of a number of compounds (up to 30 at a time) in < 1 week. This rapid in vivo assay seems to be an excellent predictor of long-term efficacy and is thus a potent screening method for selection of candidates for subsequent studies.