Biology subjects

Young, M.

Publications and source records attributed to Young, M..

31 records · Page 2Linked to original sources

bioRxiv2023

Switching circuits: Modulating NK cell response to TGF-β using novel receptors

Engineered natural killer (NK) cells offer a promising treatment strategy for multiple therapeutic areas, yet tuning cell function to diverse environmental and inhibitory contexts remains a significant challenge. An attractive strategy for functional rescue in the presence of inhibitory ligands is the use of switch receptors, surface-expressed chimeric receptors that convert an external inhibitory cue into an intracellular activation signal. Here, we discover novel engineered switch receptors in NK cells that are responsive to TGF-{beta}, a soluble inhibitory factor present in many therapeutic contexts. Through a pooled screen of an 11,131 member library, we identified multiple novel signaling endodomains and endodomain combinations that improve both the acute cytotoxicity and persistence of NK cells in the presence of TGF-{beta}, demonstrating a novel and flexible approach to switch receptor discovery.

immunology↗

bioRxiv2023

TRAFfic signals: High-throughput CAR discovery in NK cells reveals novel TRAF-binding endodomains that drive enhanced persistence and cytotoxicity

Natural killer (NK) cells are a promising alternative therapeutic platform to CAR T cells given their favorable safety profile and potent killing ability. However, CAR NK cells suffer from limited persistence in vivo, which is, in part, thought to be the consequence of limited cytokine signaling. To address this challenge, we developed an innovative high-throughput screening strategy to identify CAR endodomains that could drive enhanced persistence while maintaining potent cytotoxicity. We uncovered a family of TRAF-binding endodomains that outperform benchmarks in primary NK cells along dimensions of persistence and cytotoxicity, even in low IL-2 conditions. This work highlights the importance of cell-type-specific cell therapy engineering and unlocks a wide range of high-throughput molecular engineering avenues in NK cells.

immunology↗

bioRxiv2023

Multivalent Exosome based protein vaccine: a "mix and match" approach to epidemic viruses' challenges.

Endemic viruses are becoming increasingly the norm, and the development of a rapid and effective vaccine is emergent. Here, we used our StealthX exosome platform to express either Influenza H3 (Stealth X-Hemagglutinin, STX-H3) or SARS-CoV-2 Delta spike (Stealth X-Spike, STX-S) protein on the surface and facilitate their trafficking to the exosomes. When administered as single product, both STX-H3 and STX-S induced a strong immunization with the production of a potent humoral and cellular immune response in mice. Interestingly, these effects were obtained with administration of nanograms of protein and without adjuvant. Therefore, we tested the possibility of a multivalent vaccine: STX-H3 and STX-S exosomes were formulated together in a "mix and match" approach and the immune response was further evaluated. We showed that our STX-H3+S cocktail vaccine is as effective as the single components administered separately, resulting in a strong antibody and T-cell response. Our data show that our exosome platform has an enormous potential to revolutionize vaccinology by rapidly facilitating antigen presentation, and for therapeutics by enabling cell and tissue specific targeting.

immunology↗

bioRxiv2023

A distinct neural activity subspace for direct motor cortical influence on muscles

It remains poorly resolved when and how motor cortical output directly influences limb muscle activity through descending projections, which impedes mechanistic understanding of motor control. Here we addressed this in mice performing an ethologically inspired climbing behavior. We quantified the direct influence of forelimb primary motor cortex (caudal forelimb area, CFA) on muscles across the muscle activity states expressed during climbing. We found that CFA instructs muscle activity pattern by selectively activating certain muscles, while less frequently activating or suppressing their antagonists. From Neuropixels recordings, we identified linear combinations (components) of motor cortical activity that covary with these effects. These components differ partially from those that covary with muscle activity and differ almost completely from those that covary with kinematics. Collectively, our results reveal an instructive direct motor cortical influence on limb muscles that is selective within a motor behavior and reliant on a distinct neural activity subspace.

neuroscience↗

bioRxiv2023

Nanograms of SARS-CoV-2 Spike Protein Delivered by Exosomes Induce Potent Neutralization of Both Delta and Omicron Variants.

Exosomes are emerging as potent and safe delivery carriers for use in vaccinology and therapeutics. A better vaccine for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is needed to provide improved, broader, longer lasting neutralization of SARS-CoV-2, a more robust T cell response, enable widespread global usage, and further enhance the safety profile of vaccines given the likelihood of repeated booster vaccinations. Here, we use Capricors StealthX platform to engineer exosomes to express native SARS-CoV-2 spike Delta variant (STX-S) protein on the surface for the delivery of a protein-based vaccine for immunization against SARS-CoV-2 infection. The STX-S vaccine induced a strong immunization with the production of a potent humoral immune response as demonstrated by high levels of neutralizing antibody not only against the delta SARS-CoV-2 virus but also two Omicron variants (BA.1 and BA.5), providing broader protection than current mRNA vaccines. Additionally, both CD4+ and CD8+ T cell responses were increased significantly after treatment. Quantification of spike protein by ELISA showed that only nanograms of protein were needed to induce a potent immune response. This is a significantly lower dose than traditional recombinant protein vaccines with no adjuvant required, which makes the StealthX exosome platform ideal for the development of multivalent vaccines with a better safety profile. Importantly, our exosome platform allows novel proteins, or variants in the case of SARS-CoV-2, to be engineered onto the surface of exosomes in a matter of weeks, comparable with mRNA vaccine technology, but without the cold storage requirements. The ability to utilize exosomes for cellular delivery of proteins, as demonstrated by STX-S, has enormous potential to revolutionize vaccinology by rapidly facilitating antigen presentation at an extremely low dose resulting in a potent, broad antibody response.

immunology↗

bioRxiv2023

Exosome based multivalent vaccine: achieving potent immunization, broaden reactivity and T cell response with nanograms of proteins without any adjuvant.

Current approved vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have focused solely on the spike protein to provide immunity. The first vaccines were developed rapidly using spike mRNA delivered by lipid nanoparticles but required ultra-low storage and have had limited immunity against variations in spike. Subsequently, protein-based vaccines were developed which offer broader immunity but require significant time for development and use of an adjuvant to boost immune response. Here, exosomes were used to deliver a bi-valent protein-based vaccine, in which two independent viral proteins were used. Exosomes were engineered to express either SARS-CoV-2 Delta spike (Stealth X-Spike, STX-S) or the more conserved nucleocapsid (Stealth X-Nucleocapsid, STX-N) protein on the surface. When administered as single product (STX-S or STX-N) or in combination (STX-S+N), both STX-S and STX-N induced a strong immunization with the production of a potent humoral and cellular immune response. Interestingly, these results were obtained with administration of only nanograms of protein and without adjuvant. In two independent animal models (mouse and rabbit), administration of nanograms of the STX-S+N vaccine resulted in increased antibody production, potent neutralizing antibodies with cross-reactivity to other variants of spike and strong T-cell responses. Importantly, no competition in immune response was observed, allowing for delivery of nucleocapsid with spike to offer improved SARS-CoV-2 immunity. These data show that the StealthXTM exosome platform has an enormous potential to revolutionize vaccinology by combining the advantages of mRNA and recombinant protein vaccines into a superior, rapidly generated, low dose vaccine resulting in potent, broader immunity.

immunology↗

bioRxiv2022

Investigating the role of binding free energy, binding affinity and antibody escape in the evolution of SARS-CoV-2 spike protein.

SARS-CoV-2 is considered a pandemic virus and presents a major strain on public health globally. SARS-CoV-2 infects mammalian cells by binding to its receptor, ACE2 which is mediated by the viral spike glycoprotein, specifically the receptor binding domain (RBD) within the spike protein. Recent development of vaccines against SARS-CoV-2 spike protein are currently the best strategy to reduce morbidity and mortality from infection. Like all viruses, SARS-CoV-2 evolves which may result in mutations which are benign or alter its viral fitness. The evolution of SARS-CoV-2 may increase the virulence, possibly by increasing the infectivity of the virus through strengthening the binding of the RBD to ACE2 or enabling the virus to evade naturally or vaccine induced immune responses. To address the need to characterise the evolution of SARS-CoV-2, this study has compared SARS-CoV2 sequences globally to the Wuhan reference strain at different time points. Additionally, by assigning scores to sequence data, which quantify each sequences binding strength to ACE2 and ability to evade patient derived antibodies, we have demonstrated that over time SARS-CoV-2 has evolved in less than one year to increase its ability to evade antibodies and increase the binding free energy between the RBD and ACE2.

microbiology↗

bioRxiv2022

Structure of the Lysinibacillus sphaericus Tpp49Aa1 pesticidal protein elucidated from natural crystals using MHz-SFX

Tpp49Aa1 from Lysinibacillus sphaericus is a Toxin_10 family protein that - in combination with Cry48Aa1, a 3-domain crystal protein - has potent mosquitocidal activity, specifically against Culex quinquefasciatus mosquitoes. MHz serial femtosecond crystallography at a nano-focused X-ray free electron laser, allowed rapid and high-quality data collection to determine the Tpp49Aa1 structure at 1.62 [A] resolution from native nanocrystals. This revealed the packing of Tpp49Aa1 within these nanocrystals, isolated from sporulated bacteria, as a homodimer with a large intermolecular interface, shedding light on natural crystallization. Complementary experiments conducted at varied pH also enabled investigations of the early structural events leading up to the dissolution of natural Tpp49Aa1 crystals. Using modelling, we propose a potential interaction between Tpp49Aa1 and Cry48Aa1 that may play a role in their codependency and broaden our understanding of this two-component system. We expand the known target range, demonstrating Tpp49Aa1/Cry48Aa1 susceptibility of larvae from Anopheles stephensi, Aedes albopictus and Culex tarsalis - substantially increasing the potential use of this toxin pair in mosquito control. Further functional insights are gained using Culex cell lines to characterise cellular models for future investigations into Cry48Aa1/Tpp49Aa1 mechanism of action and to demonstrate transient detrimental effects of individual toxin components. Significance StatementThe Tpp49Aa1/Cry48Aa1 protein pair kills mosquito larvae. Innovative use of nano-focused X-ray free electron laser to match the size of natural Tpp49Aa1 nanocrystals and the highest beam intensity available in any XFEL for high-throughput data collection, allowed structural resolution to 1.62 [A]. Tpp proteins show a range of interactions with different partners to elicit toxicity. To gain insight into Tpp49Aa1, its interaction with Cry48Aa1 was modelled. We also establish cell-based assays of Tpp49Aa1/Cry48Aa1 activity. We expand the known target range to include three more mosquito species: Anopheles stephensi, Aedes albopictus and Culex tarsalis. This study will underpin future Tpp mode of action investigations and aid insecticide optimization against mosquito vectors of emerging diseases such as West Nile Virus and malaria.

biochemistry↗

bioRxiv2021

Antibodies control metabolism by regulating insulin homeostasis

Homeostasis of metabolism by hormone production is crucial to maintain physiological integrity and disbalance can cause severe metabolic disorders such as diabetes mellitus. Here, we show that antibodies recognizing insulin are key regulators of blood glucose and metabolism controlling insulin concentrations. In fact, antibody-deficient mice and immunodeficiency patients show sub-physiological blood glucose, which becomes normal after total IgG injection. We show that insulin-specific IgG antibodies found in the serum of wildtype mice or healthy individuals are responsible for this regulation. Interestingly, we identify two fractions of anti-insulin IgM which differ in their affinity to insulin. The low affinity IgM fraction (anti-insulin IgMlow) neutralizes insulin and leads to increased blood glucose while the high affinity IgM fraction (anti-insulin IgMhigh) protects insulin from neutralization by anti-insulin IgG thereby preventing blood glucose dysregulation. In contrast to anti-insulin IgMhigh, anti-insulin IgMlow binds to dsDNA suggesting that it is multi-specific. This multi-specificity mediates the formation of larger immune complexes containing insulin which results in increased uptake and degradation of insulin by macrophages in the presence of anti-insulin IgMlow as compared to anti-insulin IgMhigh. To demonstrate that high affinity anti-insulin IgM acts as protector of insulin and counteracts insulin neutralization by anti-insulin IgG, we expressed the variable regions of the same anti-insulin antibody as IgG or IgM. Strikingly, only the anti-insulin IgM regulated insulin function and prevented IgG-mediated neutralization of insulin and subsequent blood glucose dysregulation. Since anti-insulin IgMhigh is generated in the course of an immune response and affinity maturation, its protective role suggests that preventing autoimmune damage and maintaining physiological homeostasis requires adaptive tolerance mechanisms that generate protective IgM antibodies during memory responses.

immunology↗

bioRxiv2019

Modulating cellular cytotoxicity and phototoxicity of fluorescent organic salts through counterion pairing

Light-activated theranostics offer promising opportunities for disease diagnosis, image-guided surgery, and site-specific personalized therapy. However, current fluorescent dyes are limited by low brightness, high cytotoxicity, poor tissue penetration, and unwanted side effects. To overcome these limitations, we demonstrate a platform for optoelectronic tuning, which allows independent control of the optical properties from the electronic properties of fluorescent organic salts. This is achieved through cation-anion pairing of organic salts that can modulate the frontier molecular orbital without impacting the bandgap. Optoelectronic tuning enables decoupled control over the cytotoxicity and phototoxicity of fluorescent organic salts through selective generation of mitochondrial reactive oxygen species that control cell viability. We show that through counterion pairing, organic salt nanoparticles can be tuned to be either nontoxic for enhanced imaging, or phototoxic for improved photodynamic therapy.

bioengineering↗

bioRxiv2019

Integrative network modeling reveals mechanisms underlying T cell exhaustion

Failure to clear antigens causes CD8+ T cells to become increasingly hypo-functional, a state known as exhaustion. We combined manually extracted information from published literature with gene expression data from diverse model systems to infer a set of molecular regulatory interactions that underpin exhaustion. Topological analysis and simulation modeling of the network suggests CD8+ T cells undergo 2 major transitions in state following stimulation. The time cells spend in the earlier proliferative/pro-memory (PP) state is a fixed and inherent property of the network structure. Transition to the second state is necessary for exhaustion. Combining insights from network topology analysis and simulation modeling, we predict the extent to which each node in our network drives cells towards an exhausted state. We demonstrate the utility of our approach by experimentally testing the prediction that druginduced interference with EZH2 function increases the proportion of proliferative/pro-memory cells in the early days post-activation.

systems biology↗

bioRxiv2018

The Role of Gdf5 Regulatory Regions on Development of Hip Morphology and Susceptibility to Osteoarthritis and Dislocation

Given GDF5 involvement in hip development, and osteoarthritis (OA) and developmental hip dysplasia (DDH) risk, here we sought to assess the role(s) of GDF5 and its regulatory sequence on the development of hip morphology linked to injury risk. The brachypodism (bp) mouse, which harbors a Gdf5 inactivating mutation, was used to survey how Gdf5 loss of function impacts the development of hip morphology. Two transgenic Gdf5 reporter BAC lines were used to assess the spatiotemporal expression of Gdf5 regulatory sequences. Each BAC line was also used to assess the functional roles of upstream and downstream sequence on hip morphology. bp/bp mice had shorter femora with smaller femoral heads and necks as well as larger alpha angles, smaller anterior offsets, and smaller acetabula, compared to bp/+ mice (p<0.04). Regulatory sequences downstream of Gdf5 drove strong prenatal (E17) expression and low postnatal (6 months) expression across regions of femoral head and acetabulum. Conversely, upstream regulatory sequences drove very low expression at E17 and no detectable expression at 6 months. Importantly, downstream, but not upstream Gdf5 regulatory sequences fully restored all the key morphologic features disrupted in bp/bp mice. Hip morphology is profoundly affected by Gdf5 absence, and downstream regulatory sequences mediate its effects by controlling Gdf5 expression during development. This downstream region contains numerous enhancers harboring risk variants related to hip OA, DDH, and dislocation. We posit that subtle alterations to morphology driven by changes in downstream regulatory sequence underlie this locus role in hip injury risk.

genetics↗

bioRxiv2017

Transcriptional Profiling of Somatostatin Interneurons in the Spinal Dorsal Horn

The spinal dorsal horn (SDH) is comprised of distinct neuronal populations that process different somatosensory modalities. Somatostatin (SST)-expressing interneurons in the SDH have been implicated specifically in mediating mechanical pain. Identifying the transcriptomic profile of SST neurons could elucidate the unique genetic features of this population and enable selective analgesic targeting. To that end, we combined the Isolation of Nuclei Tagged in Specific Cell Types (INTACT) method and Fluorescence Activated Nuclei Sorting (FANS) to capture tagged SST nuclei in the SDH of adult male mice. Using RNA-sequencing (RNA-seq), we uncovered more than 13,000 genes. Differential gene expression analysis revealed more than 900 genes with at least 2-fold enrichment. In addition to many known dorsal horn genes, we identified and validated several novel transcripts from pharmacologically tractable functional classes: Carbonic Anhydrase 12 (Car12), Phosphodiesterase 11A (Pde11a), Protease-Activated Receptor 3 (F2rl2) and G-protein Coupled Receptor 26 (Gpr26). In situ hybridization of these novel genes revealed differential expression patterns in the SDH, demonstrating the presence of transcriptionally distinct subpopulations within the SST population. Pathway analysis revealed several enriched signaling pathways including cyclic AMP-mediated signaling, Nitric Oxide Synthase signaling, and voltage-gated calcium channels, highlighting the importance of these pathways to SST neuron function. Overall, our findings provide new insights into the gene repertoire of SST dorsal horn neurons and reveal several candidate targets for pharmacological modulation of this pain-mediating population.\n\nSignificance StatementSomatostatin(SST)-expressing interneurons in the spinal dorsal horn (SDH) are required for the perception of mechanical pain. Identifying the distinctive genes expressed by SST neurons could facilitate the development of novel, circuit-targeting analgesics. Thus, we applied cell type-specific RNA-sequencing (RNA-seq) to provide the first transcriptional profile of SST neurons in the SDH. Bioinformatic analysis revealed hundreds of genes enriched in SST neurons, including several previously undescribed genes from druggable classes (Car12, Pde11a, F2rl2 and Gpr26). Taken together, our study unveils a comprehensive transcriptional signature for SST neurons, highlights promising candidate genes for future analgesic development, and establishes a flexible method for transcriptional profiling of any spinal cord cell type.

neuroscience↗