Biology subjects

Blanchard, E. L.

Publications and source records attributed to Blanchard, E. L..

4 recordsLinked to original sources

bioRxiv2022

Ultrastructural characterization of a viral RNA and G-protein containing, membranous organelle formed in respiratory syncytial virus infected cells

Withdrawal statementThe authors have withdrawn their manuscript because since deposition of this preprint, they have become aware of the possibility that the findings reported may be an artefact. Carter et al. (J Struct Biol 2018 Jan;201(1):15-25. doi: 10.1016/j.jsb.2017.10.009) have reported that multilamellar bodies exhibit autofluorescence under cryogenic conditions. Thus, there is a possibility that stress induced by virus infection may stimulate formation of the features reported in this article, and autofluorescence, rather than specific labelling led them to identify the puncta as compartments containing RSV proteins or genomes. They are working to address these issues. Therefore, the authors do not wish this work to be cited as reference for the project. If you have any questions, please contact the corresponding author.

microbiology↗

bioRxiv2020

TRAF6-IRF5 kinetics, TRIF, and biophysical factors drive synergistic innate responses to particle-mediated MPLA-CpG co-presentation

Innate immune responses to pathogens are driven by co-presentation of multiple pathogen-associated molecular patterns (PAMPs). PAMPs and PAMP-analogs are also used as immune-adjuvants to enhance vaccine efficacy by activating various Pattern Recognition Receptors (PRRs), like Toll-like receptors (TLRs). Various combinations of PAMP adjuvants can trigger synergistic immune responses, but the underlying molecular mechanisms driving that synergy are poorly understood. Here, we used synthetic particulate carriers co-loaded with MPLA (TLR4-adjuvant) and CpG (TLR9-adjuvant) as pathogen-like particles (PLPs) to dissect the signaling pathways responsible for the integrated, dual-adjuvant immune response. PLP-based co-presentation of MPLA and CpG to mouse bone marrow derived antigen-presenting cells (BM-APCs) elicited synergistic Type-I Interferon (IFN-{beta}) and IL-12p70 responses, which were strongly influenced by the biophysical properties of PLPs. Mechanistically, we found that the adapter protein MyD88 and the Interferon-Regulatory-Factor-5 (IRF-5), but not the canonical factors IRF-3 or IRF-7, were necessary for production of both IFN-{beta} and IL12p70. TRIF signaling was required to elicit the synergistic response; the absence of TRIF abolished synergy. Importantly, both the kinetics and magnitude of downstream TRAF6 and IRF5 signaling (TRIF-TRAF-IRF5 pathway kinetics) drove the observed synergy. These results identify not only the key signaling mechanism that cooperates to generate a combinatorial response to MPLA-CpG dual engagement in BM-APCs, but they also underscore the critical role that signaling kinetics and biophysical presentation plays in integrated responses to combination adjuvants.

immunology↗

bioRxiv2020

Treating Influenza and SARS-CoV-2 via mRNA-encoded Cas13a

Here, Cas13a has been used to target and mitigate influenza virus A (IAV) and SARS-CoV-2 using a synthetic mRNA-based platform. CRISPR RNAs (crRNA) against PB1 and highly conserved regions of PB2 were screened in conjunction with mRNA-encoded Cas13a. Screens were designed such that only guides that decreased influenza RNA levels in a Cas13-mediated fashion, were valid. Cas13a mRNA and validated guides, delivered post-infection, simulating treatment, were tested in combination and across multiplicities of infection. Their function was also characterized over time. Similar screens were performed for guides against SARS-CoV-2, yielding multiple guides that significantly impacted cytopathic effect. Last, the approach was utilized in vivo, demonstrating the ability to degrade influenza RNA in a mouse model of infection, using polymer-formulated, nebulizer-based mRNA delivery. Our findings demonstrate the applicability of Cas13a in mitigating respiratory infections both in vitro and in a mouse model, paving the way for future therapeutic use.

bioengineering↗

bioRxiv2019

Modification of primary amines to higher order amines reduces in vivo hematological and immunotoxicity of cationic nanocarriers through TLR4 and complement pathways

For decades, cationic polymer nanoparticles have been investigated for nucleic acid delivery. Despite promising in vitro transfection results, most formulations have failed to translate into the clinic due to significant in vivo toxicity - especially when delivered intravenously. To address this significant problem, we investigated the detailed mechanisms that govern the complex in vivo systemic toxicity response to common polymeric nanoparticles. We determined that the toxicity response is material dependent. For branched polyethylenimine (bPEI) nanoparticles - toxicity is a function of multiple pathophysiological responses - triggering of innate immune sensors, induction of hepatic toxicity, and significant alteration of hematological properties. In contrast, for chitosan-based nanoparticles - systemic toxicity is primarily driven through innate immune activation. We further identified that modification of primary amines to secondary and tertiary amines using the small molecule imidazole-acetic-acid (IAA) ameliorates in vivo toxicity from both nanocarriers by different, material-specific mechanisms related to Toll-like receptor 4 activation (for bPEI) and complement activation driven neutrophil infiltration (for chitosan), respectively. Our results provide a detailed roadmap for evaluating in vivo toxicity of nanocarriers and identifies potential opportunities to reduce toxicity for eventual clinical translation.\n\nGraphical Abstract\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=104 SRC=\"FIGDIR/small/647305v1_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (27K):\norg.highwire.dtl.DTLVardef@63c7a7org.highwire.dtl.DTLVardef@c8ac52org.highwire.dtl.DTLVardef@a9589dorg.highwire.dtl.DTLVardef@1f8ec62_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗