Biology subjects

O'Connell, D.

Publications and source records attributed to O'Connell, D..

5 recordsLinked to original sources

bioRxiv2026

Cannabinoid CB2 receptor activation drives glucose uptake, shifting T cell metabolism.

Cannabinoid receptor 2 (CB2R) is highly expressed on immune cells, but its role in T cell metabolism remains unclear. Here, we show that CB2R activation rapidly increases glucose uptake in human Jurkat T cells and drives a broader metabolic reprogramming away from glycolysis toward oxidative metabolism and the pentose phosphate pathway. Pharmacological CB2R activation increased mitochondrial mass, spare respiratory capacity, proton leak, and NADPH production, while CB2R inverse agonism produced the opposite effects. These metabolic changes were accompanied by upregulation of key pentose phosphate pathway enzymes, including GALT and TALDO1, and were abolished in CNR2-deficient cells, confirming receptor dependence. In primary human lamina propria mononuclear cells, CB2R signalling also influenced memory and gut-homing-associated T cell phenotypes, including integrin 4{beta}7 expression. Together, these findings identify CB2R as a regulator of T cell bioenergetics and suggest that cannabinoid signalling may promote metabolic states linked to memory and tissue-homing functions in chronic intestinal inflammation. Brief SummaryO_LICB2R agonist-mediated increased glucose uptake in human T cells is lost in CNR2-deficient cells, suggesting that the response is receptor-dependent. C_LIO_LICB2R activation rewires T-cell metabolism toward increased oxidative phosphorylation, spare respiratory capacity, mitochondrial mass, and pentose phosphate pathway metabolism, including higher NADPH and PPP-enzyme expression. C_LIO_LIIn primary human intestinal immune cells, CB2R also promotes gut-homing and memory-associated T-cell phenotypes, including 4{beta}7 and CD103 integrin induction ex vivo, suggesting a possible link to exacerbation of chronic intestinal inflammation. C_LI

immunology↗

bioRxiv2025

Sequencing by Expansion (SBX) -- a novel, high-throughput single-molecule sequencing technology

Remarkable advances in high-throughput sequencing have enabled major biological discoveries and clinical applications, but achieving wider distribution and use depends critically on further improvements in scale and cost reduction. Nanopore sequencing has long held the promise for such progress, but has had limited market penetration. This is because efficient and accurate nanopore sequencing of nucleic acids has been challenged by fundamental signal-to-noise limitations resulting from the poor spatial resolution and molecular distinction of nucleobases. Here, we describe Sequencing by Expansion (SBX), a single-molecule sequencing technology that overcomes these limitations by using a biochemical conversion process to encode the sequence of a target nucleic acid molecule into an Xpandomer, a highly measurable surrogate polymer. Expanding over 50 times longer than the parent DNA templates, Xpandomers are engineered with high signal-to-noise reporter codes to enable facile, high-accuracy nanopore sequencing. We demonstrate the performance of SBX and present the specialized molecular structures, chemistries, enzymes and methods that enable it. The innovative molecular and systems engineering in SBX create a transformative technology to address the needs of existing and emerging sequencing applications.

genomics↗

bioRxiv2021

Dual targeting of salt inducible kinases and CSF1R uncouples bone formation and bone resorption

Bone formation and resorption are typically coupled, such that the efficacy of anabolic osteoporosis treatments may be limited by bone destruction. The multi-kinase inhibitor YKL-05-099 potently inhibits salt inducible kinases (SIKs) and may represent a promising new class of bone anabolic agents. Here we report that YKL-05-099 increases bone formation in hypogonadal female mice without increasing bone resorption. Postnatal mice with inducible, global deletion of SIK2 and SIK3 show increased bone mass, increased bone formation, and, distinct from the effects of YKL-05-099, increased bone resorption. No cell-intrinsic role of SIKs in osteoclasts was noted. In addition to blocking SIKs, YKL-05-099 also binds and inhibits CSF1R, the receptor for the osteoclastogenic cytokine M-CSF. Modeling reveals that YKL-05-099 binds to SIK2 and CSF1R in a similar manner. Dual targeting of SIK2/3 and CSF1R induces bone formation without concomitantly increasing bone resorption and thereby may overcome limitations of most current anabolic osteoporosis therapies.

physiology↗

bioRxiv2020

The Fc-mediated effector functions of a potent SARS-CoV-2 neutralizing antibody, SC31, isolated from an early convalescent COVID-19 patient, are essential for the optimal therapeutic efficacy of the antibody

SARS-CoV-2-neutralizing antibodies are promising therapeutics for COVID-19. However, little is known about the mechanisms of action of these antibodies or their effective dosing windows. We report the discovery and development of SC31, a potent SARS-CoV-2 neutralizing IgG1 antibody, originally isolated from a convalescent patient at day 27 after the onset of symptoms. Neutralization occurs via a binding epitope that maps within the ACE2 interface of the SARS-CoV-2 Spike protein, conserved across all common circulating SARS-CoV-2 mutants. In SARS-CoV-2 infected K18-human ACE2 transgenic mice, SC31 demonstrated potent survival benefit by dramatically reducing viral load concomitant with attenuated pro-inflammatory responses linked to severe systemic disease, such as IL-6. Comparison with a Fc-null LALA variant of SC31 demonstrated that optimal therapeutic efficacy of SC31 requires intact Fc-mediated effector functions that can further induce an IFN{gamma}-driven anti-viral immune response. Dose-dependent efficacy for SC31 was observed down to 5mg/kg when dosed before the activation of lung inflammatory responses. Importantly, despite Fc{gamma}R binding, no evidence of antibody dependent enhancement was observed with the Fc-competent SC31 even at sub-therapeutic doses. Therapeutic efficacy was confirmed in SARS-CoV-2-infected hamsters, where SC31 again significantly reduced viral load, decreased lung lesions and inhibited progression to severe disease manifestations. This study underlines the potential for significant COVID-19 patient benefit for the SC31 antibody that justifies rapid advancement to the clinic, as well as highlighting the importance of appropriate mechanistic and functional studies during development. One Sentence SummaryAnti-SARS-CoV-2 IgG1 antibody SC31 controls infection in vivo by blocking SP:ACE2 binding and triggering a Fc-mediated anti-viral response.

microbiology↗

bioRxiv2019

Biophysical characterization of DNA origami nanostructures reveals inaccessibility to intercalation binding sites

Intercalation of drug molecules into synthetic DNA nanostructures formed through self-assembled origami has been postulated as a valuable future method for targeted drug delivery. This is due to the excellent biocompatibility of synthetic DNA nanostructures, and high potential for flexible programmability including facile drug release into or near to target cells. Such favourable properties may enable high initial loading and efficient release for a predictable number of drug molecules per nanostructure carrier, important for efficient delivery of safe and effective drug doses to minimise non-specific release away from target cells. However, basic questions remain as to how intercalation-mediated loading depends on the DNA carrier structure. Here we use the interaction of dyes YOYO-1 and acridine orange with a tightly-packed 2D DNA origami tile as a simple model system to investigate intercalation-mediated loading. We employed multiple biophysical techniques including single-molecule fluorescence microscopy, atomic force microscopy, gel electrophoresis and controllable damage using low temperature plasma on synthetic DNA origami samples. Our results indicate that not all potential DNA binding sites are accessible for dye intercalation, which has implications for future DNA nanostructures designed for targeted drug delivery.

biophysics↗