Biology subjects

Cox, K.

Publications and source records attributed to Cox, K..

23 records · Page 2Linked to original sources

bioRxiv2020

Domain Binding and Isotype Dictate the Activity of Anti-human OX40 Antibodies

Previous data suggests that anti-OX40 mAb can elicit anti-tumour effects in mice through deletion of Tregs. However, OX40 also has powerful costimulatory effects on T cells which could evoke therapeutic responses. The contributions of these different effector mechanisms has not previously been systematically evaluated, particularly for mAb directed to human OX40. Therefore, we generated a novel human OX40 knock-in (KI) mouse to evaluate a panel of anti-hOX40 mAb and show that their activities relate directly to two key properties: 1) isotype – with mIgG1 mAb evoking receptor agonism and CD8+ T cell expansion and mIgG2a mAb evoking deletion of Treg and; 2) epitope - with membrane-proximal mAb delivering more powerful agonism. Intriguingly, both isotypes acted therapeutically in tumour models by engaging these different mechanisms. These findings highlight the significant impact of isotype and epitope on the modulation of anti-hOX40 mAb therapy, and indicate that CD8+ T cell expansion or Treg depletion might be preferable according to the composition of different tumours.Summary Human trials with anti-OX40 antibodies have been disappointing indicating that optimal reagents have not yet been developed. Here, using a new panel of antibodies, we show that isotype and epitope combine to determine agonistic and therapeutic activity.Competing Interest StatementMSC is a retained consultant for BioInvent International and has performed educational and advisory roles for Baxalta and Boehringer Ingleheim. He has received research funding from Roche, Gilead, Bioinvent International and GSK. BF, IT, LM and MS are employees of Bioinvent International.View Full Text

immunology↗

bioRxiv2020

Homology-directed repair involves multiple strand invasion cycles in fission yeast

Homology-directed repair of DNA double-strand breaks (DSBs) can be a highly faithful pathway. Non-crossover repair dominates in mitotically growing cells, likely through a preference for synthesis-dependent strand annealing (SDSA). While genetic studies highlight a key role for the RecQ helicase BLM/Rqh1 (in human and S. pombe cells, respectively) in promoting noncrossover repair, how homology-directed repair mechanism choice is orchestrated in time and space is not well understood. Here, we develop a microscopy-based assay in living fission yeast to determine the dynamics and kinetics of an engineered, site-specific interhomologue repair event. We observe highly efficient homology search and homology-directed repair in this system. Surprisingly, we find that the initial distance between the DSB and the donor sequence does not correlate with the duration of repair. Instead, we observe that repair is likely to involve multiple site-specific and Rad51-dependent co-localization events between the DSB and donor sequence, suggesting that efficient interhomologue repair in fission yeast often involves multiple strand invasion events. By contrast, we find that loss of Rqh1 leads to successful repair through a single strand invasion event, suggesting that multiple strand invasion cycles reflect ongoing SDSA. However, failure to repair is also more likely in rqh1{Delta} cells, which could reflect increased strand invasion at non-homologous sites. This work has implications for the molecular etiology of Bloom syndrome, caused by mutations in BLM and characterized by aberrant sister chromatid crossovers and inefficient repair.

cell biology↗

bioRxiv2019

Cis-Regulatory Accessibility Directs Muller Glial Development and Regenerative Capacity

Diseases and damage to the retina lead to losses in retinal neurons and eventual visual impairment. Although the mammalian retina has no inherent regenerative capabilities, fish have robust regeneration from Muller glia (MG). Recently, we have shown that driving expression of Ascl1 in adult mouse MG stimulates neurogenesis similar to fish regeneration. The regeneration observed in the mouse is limited in the variety of neurons that can be derived from MG; Ascl1-expressing MG primarily generate bipolar cells. To better understand the limits of MG-based regeneration in mouse retinas, we used ATAC- and RNA-seq to compare newborn progenitors with MG. Our analysis demonstrated striking similarities between MG and progenitors, with losses in regulatory motifs for neurogenesis genes. Young MG were found to have intermediate expression profiles and accessible DNA, which is mirrored in the ability of Ascl1 to direct bipolar neurogenesis in young MG. When comparing what makes bipolar and photoreceptor cells distinct from glial cells, we find that bipolar-specific accessible regions are more frequently linked to bHLH motifs and Ascl1 binding, indicating that Ascl1 preferentially binds to bipolar regions. Overall, our analysis indicates a loss of neurogenic gene expression and motif accessibility during glial maturation that may prevent efficient reprogramming.

developmental biology↗

bioRxiv2019

Systems-level analysis of monocyte responses in inflammatory bowel disease identifies IL-10 and IL-1 cytokine networks that regulate IL-23

BACKGROUND & AIMSDysregulated immune responses are the cause of inflammatory bowel diseases. Studies in both mice and humans suggest a central role of IL-23 producing mononuclear phagocytes in disease pathogenesis. Mechanistic insights into the regulation of IL-23 are prerequisite for select IL-23 targeting therapies as part of personalized medicine. METHODSWe performed transcriptomic analysis to investigate IL-23 expression in human mononuclear phagocytes and peripheral blood mononuclear cells. We investigated the regulation of IL-23 expression and used single-cell RNA-sequencing to derive a transcriptomic signature of hyper-inflammatory monocytes. Using gene network correlation analysis, we deconvolve this signature into components associated with homeostasis and inflammation in patient biopsy samples. RESULTSWe characterized monocyte subsets of healthy individuals and patients with inflammatory bowel disease that express IL-23. We identified auto- and paracrine sensing of IL-1/IL-1{beta} and IL-10 as key cytokines that control IL-23-producing monocytes. Whereas Mendelian genetic defects in IL-10 receptor signalling induced IL-23 secretion, uptake of whole bacteria induced IL-23 production via acquired IL-10 signalling resistance. We found a transcriptional signature of IL-23-producing inflammatory monocytes that predicted both disease and resistance to anti-TNF therapy and differentiated that from an IL-23-associated lymphocyte differentiation signature that was present in homeostasis and in disease. CONCLUSIONOur work identifies IL-10 and IL-1 as critical regulators of monocyte IL-23 production. We differentiate homeostatic IL-23 production from hyper-inflammation-associated IL-23 production in patients with severe ulcerating active Crohns disease and anti-TNF treatment non-responsiveness. Altogether, we identify subgroups of patients with inflammatory bowel disease that might benefit from IL-23p19 and/or IL-1/IL-1{beta}-targeting therapies upstream of IL-23. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=198 SRC="FIGDIR/small/719492v2_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@16598faorg.highwire.dtl.DTLVardef@11e5116org.highwire.dtl.DTLVardef@15d831borg.highwire.dtl.DTLVardef@4a697e_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2019

Mouse Model Systems of Autism Spectrum Disorder: Replicability and Informatics Signature

3.BackgroundPhenotyping mouse model systems of human disease has proven to be a difficult task, with frequent poor inter- and intra-laboratory replicability and translatability, particularly in behavioral domains such as social and verbal function. However, establishing robust animal model systems with strong construct validity is of fundamental importance as they are central tools for understanding disease pathophysiology and developing therapeutics. To complete our studies of mouse model systems relevant to autism spectrum disorder (ASD), we present a replication of the main findings from our two published studies comprising five genetic mouse model systems of ASD. MethodsTo assess the robustness of our previous results, we chose the two model systems that showed the greatest phenotypic differences, the Shank3/F and Cntnap2, and repeated assessments of general health, activity, and social behavior. We additionally explored all five model systems in the same framework, comparing all results obtained in this three-yearlong effort using informatics techniques to look for commonalities and differences. ResultsResults in the current study were very similar to our previously published results. The informatics signatures of the two model systems chosen for the replication showed that they were most distinguished by activity levels. Although the two model systems were opposite in this regard, those aspects of their social behavior not confounded by activity (vocalizations) were similar. ConclusionsOur results showed high intra-laboratory replicability of results, even for those with effect sizes that were not particularly large, suggesting that discrepancies in the literature may be dependent on subtle differences in testing conditions, housing enrichment, or background strains and not so much on the variability of the behavioral phenotypes. The overall informatics analysis suggests two main classes of model systems that in some aspects lie on opposite ends of the behavioral spectrum, supporting the view that autism is not a unitary concept.

animal behavior and cognition↗