Biology subjects

Shields, J.

Publications and source records attributed to Shields, J..

9 recordsLinked to original sources

bioRxiv2026

Torque-optimized body morphing enables rapid surface to underwater diving in whirligig beetles

Known for their rapid water surface locomotion, whirligig beetles (Gyrinidae) are also fast divers. They can transition from the surface to underwater swimming in under 100 ms. Diving requires them to generate sufficient hydrodynamic torque to break the water surface and reorient the body. However, the mechanism by which whirligigs create the necessary pitch-down torque is unknown. Here, we show that their diving is achieved by bending the abdomen. The inertial hydrodynamic pressure on the flexed abdomen generates the torque necessary for surface breaking and body rotation. The torque is maximized at an abdominal angle of 45{degrees}, whereas for effective diving, whirligigs display a preferential abdominal angle of around 28{degrees}, closely aligning with the angle that maximizes the torque-to-drag ratio. This abdominal angle is optimized by balancing torque generation with the drag penalty. Our findings inspire a mechanism for surface-to-underwater transition, offering design principles for multimodal robots capable of locomotion across the air-water interface.

biophysics↗

bioRxiv2026

Immune signatures of protection and progression in the airways of recent human tuberculosis household contacts

Whilst the majority of individuals infected with M. tuberculosis control the infection and remain asymptomatic, only 5-10% progress to active tuberculosis (TB)1. Previous or current infection with M. tuberculosis is detected using antigen-specific interferon (IFN)-{gamma} release assays (IGRA), which cannot identify those who will remain healthy or progress to active TB1. However, 18F-Fluorodeoxyglucose positron emission-computed tomography (PET-CT) can detect increased immune cell metabolic activity in lung parenchyma and intrathoracic lymph nodes associated with infection2. The local early immune factors dictating protection or disease progression have not been defined. To address this, we interrogated the airway immune response at single cell resolution in bronchoalveolar lavage (BAL) from extensively clinically characterised recent household contacts of TB patients, who either controlled the infection or progressed to TB disease. Using unbiased analysis of bulk and scRNA-seq of BAL samples, we define type I IFN-dependent and -independent neutrophil signatures in active TB patients and contacts that progressed to TB. We additionally report an inverse relationship between airway neutrophils and T cells, with T cells showing signatures of exhaustion, cytotoxicity and cell death in progressors and TB patients with a neutrophil dominated airway profile. Conversely, T cell signatures of protection in contacts who remained healthy were dominated by genes related to regulation, quiescence and a stem-like profile. We show that both the inflammatory neutrophil signature of TB progression and the stem-like T cell signature of non-progressors from human airways were recapitulated in scRNA-seq data from non-human primate (NHP) granulomas, associated with disease or immune protection, respectively. Our findings from early human airway responses in TB contacts reveal genes, pathways and cell states that may dictate infection outcome and inform strategies for host-directed therapy and vaccine studies.

immunology↗

bioRxiv2022

Lymph node-targeted vaccine boosting of TCR-T cell therapy enhances anti-tumor 1 function and eradicates solid tumors

While T cell receptor (TCR)-modified T cell therapies have shown promise against solid tumors, overall therapeutic benefits in clinical practice have been modest due in part to suboptimal T cell persistence and activation in vivo, alongside the possibility of tumor antigen escape. In this study, we demonstrate an approach to enhance the in vivo persistence and activation of TCR-T cells through combination with Amphiphile (AMP)-vaccination including cognate TCR-T peptides. AMP-modification improves lymph node targeting of conjugated tumor immunogens and adjuvants, thereby coordinating a robust T cell-priming endogenous immune response. Vaccine combination with TCR-T cell therapy provided simultaneous in vivo invigoration of adoptively transferred TCR-T cells and in situ priming of the endogenous anti-tumor T cell repertoire. The resulting induction of an adoptive and endogenous anti-tumor effect led to durable responses in established murine solid tumors refractory to TCR-T cell monotherapy. Protection against recurrence was associated with antigen spreading to additional tumor-associated antigens not targeted by vaccination. Enhanced anti-tumor efficacy was further correlated with pro-inflammatory lymph node transcriptional reprogramming and increased antigen presenting cell maturation, resulting in TCR-T cell expansion and functional enhancement in lymph nodes and solid tumor parenchyma without lymphodepletion. In vitro evaluation of AMP-peptides with matched human TCR-T cells targeting NY-ESO-1, mutant KRAS, and HPV16 E7 illustrated the clinical potential of AMP-vaccination to enhance human TCR-T cell proliferation, activation, and anti-tumor activity. Taken together, these studies provide rationale and evidence to support clinical evaluation of the combination of AMP-vaccination with TCR-T cell therapies to augment anti-tumor activity. SummaryAMP-vaccination targets the lymph nodes to enhance TCR-T cell therapy resulting in solid tumor eradication and durable protection against recurrence.

immunology↗

bioRxiv2022

Simulating the Tumor Microenvironment for Immune Cell Interactions via Deployable Extrusion Bioprinting

Three-dimensional (3D) bioprinting has emerged as a promising tool for constructing tumor microenvironments (TME) for cancer modelling in vitro. Realizing the translational impacts of 3D bioprinting for cancer research necessitates innovation in bioprinting workflows which integrate affordability, user-friendliness, and biological relevance. Herein, we demonstrate bioArm, a simple, yet highly effective extrusion bioprinting platform, which can be folded into a carry-on pack, and rapidly deployed between bio-facilities. BioArm enabled TME reconstruction in the form of 3D core-shell tumoroids with cancer-associated fibroblasts (CAFs). Tumoroids showed the presence of a heterogenous population of CAFs with de novo synthesized extracellular matrices, demonstrating more in vivo-like characteristics compared to conventional 2D co-culture models. Embedding the 3D printed tumoroids in an immune cell laden collagen matrix permitted tracking of the interaction between immune cells and tumoroids, and subsequent immunotherapy treatments. Our deployable extrusion bioprinting workflow could significantly widen the accessibility of 3D bioprinting for gaining mechanistic understanding in TME, and for developing strategies in cancer drug testing.

bioengineering↗

bioRxiv2021

SARS-COV-2 Recombinant Receptor-Binding-Domain (RBD) Induces Neutralising Antibodies Against Variant Strains of SARS-CoV-2 and SARS-CoV-1

SARS-CoV-2 is the etiological agent of COVID19. There are currently several licensed vaccines approved for human use and most of them are targeting the spike protein (or virion) in the virion envelope to induce protective immunity. Recently, variants that spread more quickly have emerged. There is evidence that some of these variants are less sensitive to neutralization in vitro, but it is not clear whether they can evade vaccine induced protection. In this study, we tested the utility of SARS-CoV-2 spike RBD as a vaccine antigen and explore the effect of formulation with Alum/MPLA or AddaS03 adjuvants. Our results indicate RBD induces high titers of neutralizing antibodies and activates strong cellular immune responses. There is also significant cross-neutralisation of variants B1.1.7 and B.1.351 and to a lesser extent, SARS-CoV-1. These results indicate that recombinant RBD can be a viable candidate as a stand-alone vaccine or as a booster shot to diversify our strategy for COVID19 protection.

microbiology↗

bioRxiv2020

Erythroid precursors and progenitors suppress adaptive immunity and get invaded by SARS-CoV-2

SARS-CoV-2 infection is associated with lower blood oxygen levels even in patients without hypoxia requiring hospitalization. This discordance illustrates the need for a more unifying explanation as to whether SARS-CoV-2 directly or indirectly affects erythropoiesis. Here we show significantly enriched CD71+ erythroid precursors/progenitors in the blood circulation of COVID-19 patients that have distinctive immunosuppressive properties. A subpopulation of abundant erythroid cells, CD45+CD71+cells, co-express ACE2, TMPRSS2, CD147, CD26 and these can be infected with SARS-CoV-2. In turn, pre-treatment of erythroid cells with dexamethasone significantly diminished ACE2/TMPRSS2 expression and subsequently reduced their infectivity with SARS-CoV-2. Taken together, pathological abundance of erythroid cells might reflect stress erythropoiesis due to the invasion of erythroid progenitors by SARS-CoV-2. This may provide a novel insight into the impact of SARS-CoV-2 on erythropoiesis and hypoxia seen in COVID-19 patients.

immunology↗

bioRxiv2020

Feline coronavirus drug inhibits the main protease of SARS-CoV-2 and blocks virus replication

The COVID-19 pandemic, attributed to the SARS-CoV-2 coronavirus infection, resulted in millions infected worldwide and an immediate need for antiviral treatments. The main protease (Mpro) in SARS-CoV-2 is a viable drug target because of its essential role in the cleavage of the virus polypeptide and subsequent viral replication. Feline infectious peritonitis, a fatal infection in cats caused by a coronavirus, was successfully treated previously with a dipeptide-based protease inhibitor. Here we show this drug, GC376, and its analog GC373, are effective inhibitors of the Mpro from both SARS-CoV and SARS-CoV-2 with IC50 values in the nanomolar range. Crystal structures of the SARS-CoV and SARS-CoV-2 Mpro with these inhibitors have a covalent modification of the nucleophilic Cys145. NMR analysis reveals that inhibition proceeds via reversible formation of a hemithioacetal. GC373 and GC376 are potent inhibitors of SARS-CoV-2 in cell culture, with EC50 values near one micromolar and little to no toxicity. These protease inhibitors are soluble, non-toxic, and bind reversibly. They are strong drug candidates for the treatment of human coronavirus infections because they have already been successful in animals (cats). The work here lays the framework for their use in human trials for the treatment of COVID-19.

biochemistry↗

bioRxiv2018

Tumor pre-conditioning of draining lymph node stroma by lactic acid

Communication between tumors and the stroma of tumor draining lymph nodes (TDLNs) exists before metastasis arises, altering structure and function of the TDLN niche. Transcriptional profiling of fibroblastic reticular cells (FRCs), the dominant stromal population of the LN, revealed reprogramming of these cells in immune related pathways, but also in fibroblast activation and mitochondrial function. However, tumor derived factors driving the changes in FRCs remained to be identified. Taking an unbiased approach, we show that lactate, a metabolite released by cancer cells, elicits upregulation of Pdpn and Thy1 in FRCs of TDLNs, making them akin to activated fibroblasts found at the primary tumor site. Furthermore, we show that tumor-derived lactate alters mitochondrial function of FRCs of TDLNs. Thus, our results demonstrate a novel mechanism by which a tumor-derived metabolite modulates the function of fibroblasts in TDLNs.

cancer biology↗

bioRxiv2017

Single cell transcriptomics of regulatory T cells reveals trajectories of tissue adaptation

Non-lymphoid tissues (NLTs) harbour a pool of adaptive immune cells, the development and phenotype of which remains largely unexplored. Here, we used single-cell RNA-seq to characterise CD4+ regulatory (Treg) and memory (Tmem) T cells in mouse skin and colon, the respective draining lymph nodes and spleen. From this data, we modelled a continuous lymphoid-to-NLT trajectory for Treg, and reconstructed the mechanisms of cell migration and NLT adaption. This revealed a shared transcriptional programme of NLT priming in both skin and colon-associated lymph nodes, followed by tissue-specific adaptation. Predicted migration kinetics were validated using a melanoma-induction model, emphasizing the relevance of key regulators and receptors, including Batf, Rora, Ccr8, Samsn1. Finally, we profiled human blood and NLT Treg and Tmem cells, identifying cross-mammalian conserved tissue signatures. In summary, we have identified molecular signals mediating NLT Treg recruitment and tissue adaptation through the combined use of computational prediction and in vivo validation.

immunology↗