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Tomlinson, D. C.

Publications and source records attributed to Tomlinson, D. C..

7 recordsLinked to original sources

Targeting Tenascin-C-Toll-like Receptor 4 signalling with Adhiron-derived small molecules - a viable strategy for reducing fibrosis in Systemic Sclerosis

Tissue fibrosis is a hallmark of systemic sclerosis (SSc) and results from the excessive production and deposition of collagen and other extracellular matrix proteins by resident fibroblasts. This excessive connective tissue accumulation leads to tissue disruption and subsequent dysfunction in the skin, lungs and other internal organs. Recent studies highlight a role for the matricellular protein Tenascin C in SSc, whereby its stimulation of Toll-like receptor 4 triggers self-sustaining fibroblast activation and ensuing fibrosis. We have utilised Adhiron guided ligand discovery to generate small molecules that target the fibrinogen-like globe domain of Tenascin C, a region involved in Toll-like receptor 4 activation and have demonstrated a reduction in the profibrotic phenotype of human dermal fibroblasts. These studies may facilitate the development of effective targeted therapy for fibrosis in SSc and other fibrotic diseases. Moreover, it highlights the utility of Adhiron guided ligand discovery to generate small molecule inhibitors to selectively modulate proteins. HighlightsO_LIAdhiron screening was undertaken to identify binders to the FBG domain of Tenascin C and the crystal structure of the FBG-Adhiron binding was resolved. C_LIO_LIAdhiron guided ligand discovery was used to generate small molecule inhibitors that selectively target the FBG domain of Tenascin C. C_LIO_LISPR was used to show binding of these molecules to the FBG domain of Tenascin C C_LIO_LIThe small molecule inhibitors generated attenuated TGF{beta}-mediated fibrosis in dermal fibroblasts C_LI

physiology↗

Structural characterization and inhibition of the interaction between ch-TOG and TACC3

The mitotic spindle is a bipolar array of microtubules, radiating from the poles which each contain a centrosome, embedded in pericentriolar material. Two proteins, ch-TOG and TACC3, have multiple functions at the mitotic spindle due to operating alone, together or in complex with other proteins. To distinguish these activities, we need new molecular tools to dissect their function. Here, we present the structure of the -helical bundle domain of ch-TOG that mediates its interaction with TACC3 and a structural model describing the interaction, supported by biophysical and biochemical data. We have isolated Affimer tools to precisely target the ch-TOG-binding site on TACC3 in live cells, which displace ch-TOG without affecting the spindle localization of other protein complex components. Inhibition of the TACC3-ch-TOG interaction led unexpectedly to fragmentation of the pericentriolar material in metaphase cells following the formation of a bipolar spindle and delayed mitotic progression; uncovering a novel role of TACC3-ch-TOG in maintaining pericentriolar material integrity during mitosis to ensure timely cell division.

cell biology↗

VelcroVax: a bolt-on vaccine platform technology improves antibody titres against a viral glycoprotein in mice

Having varied approaches to the design and manufacture of vaccines is critical in being able to respond to worldwide needs and to newly emerging pathogens. Virus-like particle (VLP) vaccines form the basis of two of the most successful licensed vaccines (against hepatitis B virus (HBV) and human papillomavirus). They are produced by recombinant expression of viral structural proteins, which self-assemble into immunogenic nanoparticles. VLPs can also be modified to present unrelated antigens, and here we describe a universal bolt-on vaccine platform (termed VelcroVax) where the capturing VLP and the target antigen (hapten) are produced separately. We utilise a modified HBV core (HBcAg) VLP, with surface expression of a high-affinity binding sequence (Affimer) directed against a SUMO tag and use this to capture SUMO-tagged gp1 glycoprotein from the arenavirus, Junin virus (JUNV). Using this model system, we have solved high-resolution structures of VelcroVax VLPs, and shown that the VelcroVax-JUNV gp1 complex induces superior humoral immune responses compared to the non-complexed viral protein. We propose that this system could be modified to present a range of haptens and therefore form the foundation of future rapid-response vaccination strategies.

immunology↗

RAS-inhibiting biologics identify and probe druggable pockets including an SII-α3 allosteric site.

RAS mutations are the most common oncogenic drivers across human cancers, but there remains a paucity of clinically-validated pharmacological inhibitors of RAS, as druggable pockets have proven difficult to identify. We have identified two RAS-binding Affimer proteins, K3 and K6, that inhibit nucleotide exchange and downstream signalling pathways with distinct isoform and mutant profiles. Affimer K6 is the first biologic to bind in the SI/SII pocket, whilst Affimer K3 is the first non-covalent inhibitor of the SII region, revealing a novel RAS conformer with a large, druggable SII/3 pocket. This work demonstrates the potential of using biologics with small interface surfaces to select novel druggable conformations in conjunction with pharmacophore identification for hard-to-drug proteins.

molecular biology↗

Piggybacking on the Cholera Toxin: Identification of a Toxoid-binding Protein as an Approach for Targeted Delivery of Proteins to Motor Neurons

A significant unmet need exists for the delivery of biologic drugs such as polypeptides or nucleic acids, to the central nervous system (CNS) for the treatment and understanding of neurodegenerative diseases. Naturally occurring toxoids have been considered as tools to meet this need. However, due to the complexity of tethering macromolecular drugs to toxins, and the inherent dangers of working with large quantities of recombinant toxin, no such route has been successfully exploited. Developing a method where toxoid and drug can be assembled immediately prior to in vivo administration has the potential to circumvent some of these issues. Using a phage-display screen, we identified two antibody mimetics, Anti-Cholera Toxoid Affimer (ACTA) -A2 and ACTA-C6 that non-covalently associate with the non-binding face of the cholera toxin B-subunit. In a first step toward the development of a non-viral motor neuron drug-delivery vehicle, we show that Affimers can be selectively delivered to motor neurons in vivo.

biochemistry↗

A high-content screen profiles cytotoxic microRNAs in pediatric and adult glioblastoma cells and identifies miR-1300 as a potent inducer of cytokinesis failure

BackgroundMicroRNAs play an important role in the regulation of mRNA translation, and have therapeutic potential in cancer and other diseases.\n\nMethodsTo profile the landscape of microRNAs with significant cytotoxicity in the context of glioblastoma (GBM), we performed a high-throughput screen using a synthetic oligonucleotide library representing all known human microRNAs in adult and pediatric GBM cells. Bio-informatics analysis were used to refine this list and the top seven microRNAs were validated in a larger panel of cells by flow-cytometry, and RTqPCR. The downstream mechanism of the strongest and most consistent candidate was investigated by siRNAs, 3UTR luciferase assays and Western Blotting.\n\nResultsOur screen identified [~]100 significantly cytotoxic microRNAs with 70% concordance between cell lines. MicroRNA-1300 (miR-1300) was the most potent and robust candidate. We observed a striking binucleated phenotype in miR-1300 expressing cells and characterized the mechanism of action as cytokinesis failure followed by apoptosis, which was observed in an extended GBM cell panel including two stem-like patient-derived cultures. We identified the physiological role of miR-1300 as a regulator of endomitosis in megakaryocyte differentiation where blockade of cytokinesis is an essential step. In glioblastoma cells, the oncogene Epithelial Cell Transforming 2 (ECT2) was validated as a direct key target of miR-1300. ECT2 siRNA phenocopied the effects of miR-1300, and its overexpression led to a significant rescue of miR-1300 induced binucleation.\n\nConclusionMiR-1300 was identified as a novel regulator of endomitosis with translatable potential for therapeutic application. The datatasets will be a resource for the neuro-oncology community.\n\nKey points (2 or 3 key points 85 characters plus spaces each)70% of cytotoxic microRNAs were shared between adult and pediatric glioblastoma cells\n\nMiR-1300 expression is restricted to endomitosis within megakaryocyte differentiation\n\nMiR-1300s ectopic expression is a potent and promising therapeutic tool in cancer\n\nImportance of StudyPrevious functional studies of microRNAs involved in the regulation of glioblastoma cell proliferation and/or survival have focused on adult glioblastoma alone and are restricted to only a few microRNAs at a time. Our study provides the first encompassing landscape of potent cytotoxic microRNAs in pediatric and adult glioblastoma.\n\nNot only, does our data provide an invaluable resource for the research community but it also revealed that 70% of microRNAs with significant cytotoxicity were shared by adult and pediatric cells. Finally, we identified and characterized the previously undescribed role of microRNA-1300 in the tight regulation of megakaryocyte differentiation into platelets and how, when expressed outside of this context, miR-1300 consistently causes cytokinesis failure followed by apoptosis, and thus represents a powerful cytotoxic tool with potential for translation towards therapeutic applications.

cancer biology↗

Selective Affimers Recognize BCL-2 Family Proteins Through Non-Canonical Structural Motifs

The BCL-2 family is a challenging set of proteins to target selectively due to sequence and structural homologies across the family. Selective ligands for the BCL-2 family regulators of apoptosis are desirable as probes to understand cell biology and apoptotic signalling pathways, and as starting points for inhibitor design. We have used phage display to isolate Affimer reagents (non-antibody binding proteins based on a conserved scaffold) to identify ligands for MCL-1, BCL-xL, BCL-2, BAK and BAX, then used multiple biophysical characterisation methods to probe the interactions. We established that purified Affimers elicit selective and potent recognition of their target BCL-2 protein. For anti-apoptotic targets, competitive inhibition of their canonical protein-protein interactions is demonstrated. Co-crystal structures reveal an unprecedented mode of molecular recognition; where a BH3 helix is normally bound, flexible loops from the Affimer dock into the BH3 binding cleft. Moreover, the Affimers induce a change in the target proteins towards a desirable drug bound like conformation. These results indicate Affimers can be used as alternative templates to inspire design of selective BCL-2 family modulators, and provide proof-of-concept for the elaboration of selective non-antibody binding reagents for use in cell-biology applications.

biochemistry↗