Scientists face growing pressure to move away from using traditional animal toxicity tests to determine whether manufactured chemicals are safe. Numerous ethical, scientific, business, and ...legislative incentives will help to drive this shift. However, a number of hurdles must be overcome in the coming years before non-animal methods are adopted into widespread practice, particularly from regulatory, scientific, and global perspectives. Several initiatives are nevertheless underway that promise to increase the confidence in newer alternative methods, which will support the move towards a future in which less data from animal tests is required in the assessment of chemical safety.
Rodent models produce data which underpin biomedical research and non-clinical drug trials, but translation from rodents into successful clinical outcomes is often lacking. There is a growing body of ...evidence showing that improving experimental design is key to improving the predictive nature of rodent studies and reducing the number of animals used in research. Age, one important factor in experimental design, is often poorly reported and can be overlooked. The authors conducted a survey to assess the age used for a range of models, and the reasoning for age choice. From 297 respondents providing 611 responses, researchers reported using rodents most often in the 6–20 week age range regardless of the biology being studied. The age referred to as ‘adult’ by respondents varied between six and 20 weeks. Practical reasons for the choice of rodent age were frequently given, with increased cost associated with using older animals and maintenance of historical data comparability being two important limiting factors. These results highlight that choice of age is inconsistent across the research community and often not based on the development or cellular ageing of the system being studied. This could potentially result in decreased scientific validity and increased experimental variability. In some cases the use of older animals may be beneficial. Increased scientific rigour in the choice of the age of rodent may increase the translation of rodent models to humans.
•GPCR drug discovery is hindered by limited access to purified receptor reagents.•Polymer technology (PoLiPa) enables purification of GPCRs that remain in their lipid environment.•This vastly ...increases access to and simplifies GPCR purification.•PoLiPa are amenable to biophysical / structural experiments essential to modern drug discovery.•We anticipate that this will herald a revolution in GPCR drug discovery.
G-protein-coupled receptor (GPCR) drug research is presently hindered by the technical challenges associated with generating purified receptors. Consequently, the application of critical modern discovery technologies has been limited, and the vast untapped opportunity for new GPCR-directed medicines is not being realised. A simple but transformative solution is to purify receptors without removing them from their native phospholipid environment by using polymer lipid particle (PoLiPa) technology, with reagents such as styrene-maleic acid co-polymer (SMA). Compared with contemporary detergent-based and stabilising mutagenesis methods, the PoLiPa approach is simple and generic and, therefore, offers huge advantages, with the potential to revolutionise GPCR research by facilitating the availability of the purified receptors that are required for structural biology, biophysical, and panning technologies.
PoLiPa technology (a.k.a. SMALPs) enables purification of GPCRs while they remain in their natural lipid environment, thus avoiding many of the challenges associated with current techniques and, therefore, increasing access to modern drug discovery techniques.
The IKK‐related kinases, IKKε and TBK1, have essential roles in innate immunity in part through modifying MYD88 signalling from the Toll‐like receptors to regulate NF‐κB signalling. We investigated ...the expression and function of IKKε and TBK1, in diffuse large B‐cell lymphoma (DLBCL). DLBCL cell lines and patient‐derived xenografts were used to determine their sensitivity to IKKε and TBK1 inhibitors. To understand the function of IKKε and TBK1 secreted factors were determined following administration of inhibitors. Gene expression microarrays were used to determine the transcriptional effects of inhibitors. Higher TBK1 mRNA levels associated with poorer clinical outcome but IKKε and TBK1 were expressed in both germinal centre and non‐germinal centre types of DLBCL. Survival of cell lines Ly10, Ly03 and Pfeiffer, and of some primary human lymphoma cells, was suppressed by a small molecule IKKε/TBK1 inhibitor, DMX3433. DMX3433 reduced IL‐10 production from Ly10 and repressed NF‐κB mediated transcription. Inhibition of IKKε and TBK1 warrants further investigation as a potential therapeutic route to suppress NF‐κB signalling in lymphoma.
Although much of the national opt-out movement is parent driven, the Colorado opt-out movement involved considerable efforts from high school students. This study explores the geography of the ...Colorado opt-out movement among secondary students, drawing upon social movements theory. We utilize the Colorado Measures of Academic Success (CMAS) as a measure of opt-out behavior in Colorado between 2016–2019. We also examine school-level demographic data. We first applied ordinary least squares regression and then utilize multiscale geographically weighted regression (MGWR) to examine the relationships between school-level demographics and opting out behavior for 11th-grade standardized assessments in Colorado. This analysis demonstrates the importance of geography in enacting social networks surrounding the opt-out movement in the state of Colorado. This study offers insight into opting out in the unique context of youth activism in Colorado, with a specific focus on geographical analysis.
Heart disease is a paramount cause of global death and disability. Although cardiomyocyte death plays a causal role and its suppression would be logical, no clinical counter-measures target the ...responsible intracellular pathways. Therapeutic progress has been hampered by lack of preclinical human validation. Mitogen-activated protein kinase kinase kinase kinase-4 (MAP4K4) is activated in failing human hearts and relevant rodent models. Using human induced-pluripotent-stem-cell-derived cardiomyocytes (hiPSC-CMs) and MAP4K4 gene silencing, we demonstrate that death induced by oxidative stress requires MAP4K4. Consequently, we devised a small-molecule inhibitor, DMX-5804, that rescues cell survival, mitochondrial function, and calcium cycling in hiPSC-CMs. As proof of principle that drug discovery in hiPSC-CMs may predict efficacy in vivo, DMX-5804 reduces ischemia-reperfusion injury in mice by more than 50%. We implicate MAP4K4 as a well-posed target toward suppressing human cardiac cell death and highlight the utility of hiPSC-CMs in drug discovery to enhance cardiomyocyte survival.
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•Human iPSC-cardiomyocytes were used for MAP4K4 target validation and drug discovery•MAP4K4 shRNA protects hiPSC-cardiomyocytes from lethal oxidative stress•MAP4K4 inhibitors promote hiPSC-cardiomyocyte survival and function•MAP4K4 inhibition markedly reduces cardiac ischemia-reperfusion injury in mice
Using human iPSC-derived cardiomyocytes to enhance cardiac drug discovery, Fiedler et al. performed MAP4K4 target validation by gene silencing in this human model. MAP4K4 inhibitors augment human cardiomyocyte viability and function in 2D culture and 3D engineered heart tissue. An exemplar successfully reduces infarct size in proof-of-principle studies in mice.
Histone lysine methyltransferases (HKMTs) are an important class of targets for epigenetic therapy. 1 (chaetocin), an epidithiodiketopiperazine (ETP) natural product, has been reported to be a ...specific inhibitor of the SU(VAR)3-9 class of HKMTs. We have studied the inhibition of the HKMT G9a by 1 and functionally related analogues. Our results reveal that only the structurally unique ETP core is required for inhibition, and such inhibition is time-dependent and irreversible (in the absence of DTT), ultimately resulting in protein denaturation. Mass spectrometric data provide a molecular basis for this effect, demonstrating covalent adduct formation between 1 and the protein. This provides a potential rationale for the selectivity observed in the inhibition of a variety of HKMTs by 1 in vitro and has implications for the activity of ETPs against these important epigenetic targets.
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