Biology subjects

Smith, T. R.

Publications and source records attributed to Smith, T. R..

8 recordsLinked to original sources

bioRxiv2026

Environmental Amino Acid Sensing Regulates the Rate of ASC Translation and NLRP3 Inflammasome Assembly

The NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome is a multiprotein signaling complex that triggers pyroptotic cell death and interleukin (IL)-1 family cytokine release during infection and cell injury. Its assembly is driven by the adaptor protein, apoptosis-associated speck-like protein containing a CARD (ASC), whose filamentation forms a supramolecular speck upon NLRP3 activation to amplify inflammasome signaling. While the NLRP3 inflammasome is well appreciated as a sensor of environmental danger and damage, little is known about how homeostatic environmental factors like dietary metabolites regulate its activity. Here, we find that environmental availability of the branched-chain amino acids (BCAAs), leucine, isoleucine, and valine, controls NLRP3 inflammasome assembly. While ASC is typically viewed as a constitutively expressed, unregulated inflammasome component, we find that Toll-like receptor 4 (TLR4) activation triggers localization of ASC mRNA to the perinuclear space. Moreover, our data demonstrate that ASC undergoes TLR4-driven translational bursting from polyribosomes during inflammasome priming. This translational engagement is dependent on BCAA availability and mechanistic target of rapamycin (mTOR) activity, which regulate the kinetics of inflammasome assembly. In contrast, the translation of NLRP3 and caspase-1 is largely insensitive to these inputs. Furthermore, we find that BCAAs regulate NLRP3 inflammasome activation in both mouse and human macrophages, in the context of bacterial infection, and during lipopolysaccharide (LPS)-induced sepsis in vivo. Altogether, this work unveils a novel inflammasome priming event governed by the amino acid environment. These findings further highlight how the activity of proteins maintained in equilibrium like ASC can be dynamically regulated through rapid changes in mRNA translation.

immunology↗

bioRxiv2026

The Effects of Prelimbic Inhibition on Time-based Intervention and Impulsive Choice

Impulsive choice is the suboptimal preference for a smaller-sooner (SS, "impulsive") option over a larger-later (LL, "self-controlled") option. Fixed-interval (FI) training delivers delayed-reinforcement trials to increase LL choices and improve FI timing precision. While there are plenty of studies exploring the neurobiological factors underlying impulsive choice, it is unknown what neurobiological changes account for the FI training effects. The prelimbic cortex (PL) region is implicated in both impulsive choice and timing. To investigate the role of the PL, we used designer receptors exclusively activated by designer drugs (GiDREADDs) to reversibly inhibit the PL during either the FI training phase or the follow-up impulsive choice task in male and female Sprague-Dawley rats. Compared to a control group, the GiDREADDs rats showed reduced LL choices when CNO was administered during the FI training or impulsive choice tasks. GiDREADDS did not alter response rates or latency to choose. Overall, these data demonstrate that inhibition of the PL increases impulsive choice and may block the effect of the FI training to improve self-control.

animal behavior and cognition↗

bioRxiv2021

Large positive ecological changes of small urban greening actions

The detrimental effects of human-induced environmental change on people and other species are acutely manifested in urban environments. While urban greenspaces are known to mitigate these effects and support functionally diverse ecological communities, evidence of the ecological outcomes of urban greening remains scarce. We use a longitudinal observational design to provide empirical evidence of the putative ecological benefits of greening actions. We show how a small greening action quickly led to large positive changes in the richness, demographic dynamics, and network structure of a depauperate insect community. An increase in the diversity and complexity of the plant community led to, after only three years, a large increase in insect species richness, a greater probability of occurrence of insects within the greenspace, and a higher number and diversity of interactions between insects and plant species. We demonstrate how large ecological benefits may be derived from investing in small greening actions and how these contribute to bring indigenous species back to greenspaces where they have become rare or locally extinct. Our findings provide crucial evidence that support best practice in greenspace design and contribute to re-invigorate policies aimed at mitigating the negative impacts of urbanisation on people and other species.

ecology↗

bioRxiv2021

Design and immunogenicity of a Pan-SARS-CoV-2 synthetic DNA vaccine

Here we have employed SynCon(R) design technology to construct a DNA vaccine expressing a pan-Spike immunogen (INO-4802) to induce broad immunity across SARS-CoV-2 variants of concern (VOC). Compared to WT and VOC-matched vaccines which showed reduced cross-neutralizing activity, INO-4802 induced potent neutralizing antibodies and T cell responses against WT as well as B.1.1.7, P.1, and B.1.351 VOCs in a murine model. In addition, a hamster challenge model demonstrated that INO-4802 conferred superior protection following intranasal B.1.351 challenge. Protection against weight loss associated with WT, B.1.1.7, P.1 and B.1.617.2 challenge was also demonstrated. Vaccinated hamsters showed enhanced humoral responses against VOC in a heterologous WT vaccine prime and INO-4802 boost setting. These results demonstrate the potential of the pan-SARS-CoV-2 vaccine, INO-4802 to induce cross-reactive immune responses against emerging VOC as either a standalone vaccine, or as a potential boost for individuals previously immunized with WT-matched vaccines.

immunology↗

bioRxiv2021

INO-4800 DNA Vaccine Induces Neutralizing Antibodies and T cell Activity Against Global SARS-CoV-2 Variants

Global surveillance has identified emerging SARS-CoV-2 variants of concern (VOC) associated with broadened host specificity, pathogenicity, and immune evasion to vaccine induced immunity. Here we compared humoral and cellular responses against SARS-CoV-2 VOC in subjects immunized with the DNA vaccine, INO-4800. INO-4800 vaccination induced neutralizing antibodies against all variants tested, with reduced levels detected against B.1.351. IFN{gamma} T cell responses were fully maintained against all variants tested.

immunology↗

bioRxiv2020

Human Polyomavirus-Encoded Circular RNAs

Circular RNAs (circRNAs) are a conserved class of RNAs with diverse functions. A subset of circRNAs are translated into peptides. Here we describe circular RNAs encoded by human polyomaviruses (HPyVs), including circular forms of RNAs encoding variants of the previously described alternative large T antigen open reading frame (ALTO) gene. Circular ALTO RNAs (circALTOs) can be detected in virus positive Merkel cell carcinoma (VP-MCC) cell lines and tumor samples. CircALTOs are stable, predominantly located in the cytoplasm, and N6-methyladenosine (m6A) modified. MCPyV circALTOs produce ALTO protein in cultured cells. MCPyV ALTO promotes the transcription of co-transfected reporter genes. MCPyV circALTOs are enriched in exosomes derived from VP-MCC lines and circALTO-transfected 293T cells, and purified exosomes can mediate ALTO expression and transcriptional activation. The related trichodysplasia spinulosa polyomavirus (TSPyV) also expresses a circALTO that can be detected in infected tissues and produces ALTO protein in cultured cells. Thus, human polyomavirus circRNAs are expressed in human tumors and tissues, encode for proteins, and may contribute to the infectious and tumorigenic properties of these viruses.

molecular biology↗

bioRxiv2020

Intradermal-delivered DNA vaccine provides anamnestic protection in a rhesus macaque SARS-CoV-2 challenge model

Coronavirus disease 2019 (COVID-19), caused by the SARS-CoV-2 virus, has had a dramatic global impact on public health, social, and economic infrastructures. Here, we assess immunogenicity and anamnestic protective efficacy in rhesus macaques of the intradermal (ID)-delivered SARS-CoV-2 spike DNA vaccine, INO-4800. INO-4800 is an ID-delivered DNA vaccine currently being evaluated in clinical trials. Vaccination with INO-4800 induced T cell responses and neutralizing antibody responses against both the D614 and G614 SARS-CoV-2 spike proteins. Several months after vaccination, animals were challenged with SARS-CoV-2 resulting in rapid recall of anti-SARS-CoV-2 spike protein T and B cell responses. These responses were associated with lower viral loads in the lung and with faster nasal clearance of virus. These studies support the immune impact of INO-4800 for inducing both humoral and cellular arms of the adaptive immune system which are likely important for providing durable protection against COVID-19 disease.

immunology↗

bioRxiv2020

Indigenous plants promote insect biodiversity in urban greenspaces

The contribution of urban greenspaces to support biodiversity and provide benefits for people is increasingly recognised. However, ongoing management practices still favour (1) vegetation oversimplification, often limiting greenspaces to lawns and tree canopy rather than multi-layered vegetation that includes under and midstorey; and (2) the use of nonnative plant species. These practices likely hinder the potential of greenspaces to sustain indigenous biodiversity, particularly for taxa like insects, that rely on plants for food and habitat. Yet, little is known about which plant species may maximise positive outcomes for taxonomically and functionally diverse insect communities in urban greenspaces. Additionally, while urban environments are expected to experience high rates of introductions, quantitative assessments of the relative occupancy of indigenous vs. introduced insect species in greenspace are rare - hindering understanding of how greenspace management may promote indigenous biodiversity while limiting the establishment of introduced insects. Using a hierarchically replicated study design across 15 public parks, we recorded occurrence data from 552 insect species on 133 plant species - differing in planting design element (lawn, midstorey and tree canopy), midstorey growth form (forbs, lilioids, graminoids and shrubs) and origin (nonnative, native and indigenous) - to assess: (1) the relative contributions of indigenous and introduced insect species and (2) which plant species sustained the highest number of indigenous insects. Our data indicates that the insect community was predominately composed of indigenous rather than introduced species. Our findings further highlight the core role of multi-layered vegetation in sustaining high insect biodiversity in urban areas, with indigenous midstorey and canopy representing key elements to maintain rich and functionally diverse indigenous insect communities. Intriguingly, graminoids supported the highest indigenous insect richness across all studied growth forms by plant origin groups. Taken together, our study emphasise the opportunity posed by indigenous understory and midstorey plants, particularly indigenous graminoids in our study area, to promote indigenous insect biodiversity in urban greenspaces. Our work provides a blueprint and stimulus for built-environment professionals to incorporate into their practice plant species palettes that foster a larger presence of indigenous over regionally native or nonnative plant species, whilst incorporating a broader mixture of midstorey growth forms.

ecology↗