Biology subjects

Pryce, R.

Publications and source records attributed to Pryce, R..

4 recordsLinked to original sources

bioRxiv2024

Geographic characterization of RPE structure and lipid changes in the PEX1-p.Gly844Asp mouse model for Zellweger spectrum disorder.

Peroxisome Biogenesis Disorders-Zellweger Spectrum (PBD-ZSD) are a heterogenous group of autosomal recessive disorders caused by defects in PEX genes whose proteins are required for peroxisome assembly and function. Peroxisomes are ubiquitous organelles that play a critical role in complex lipid metabolism. Dysfunctional peroxisomes in ZSD cause multisystem effects, with progressive retinal degeneration (RD) leading to childhood blindness being one of the most frequent clinical findings. Despite progress in understanding the role of peroxisomes in normal cellular functions, much remains unknown about how their deficiency causes RD, and there is no treatment. To study RD pathophysiology in this disease, we used the knock-in PEX1-p.GlyG844Asp (G844D) mouse model of milder ZSD, which represents the common human PEX1-p.Gly843Asp allele. We previously reported diminished retinal function, functional vision, and neural retina structural defects in this model. Beyond the neural retina, structural defects in retinal pigment epithelium (RPE) have been reported in ZSD patients and murine models with single peroxisome enzyme deficiency, suggesting that RPE degeneration may contribute to overall RD progression in this disease. Here, we investigate the RPE phenotype in our PEX1-G844D mouse model, observing morphological, inflammatory, and lipid changes at 1, 3, and 6 months of age. We report that RPE cell degeneration appears at 3 months of age and worsens with time, starts in the dorsal pole, and is accompanied by subretinal inflammatory cell infiltration. We match these events with lipid remodelling using imaging mass spectrometry which allowed regional analysis specific to the RPE cell layer. We identified 47 lipid alterations that precede structural changes, 10 of which are localized to the dorsal pole. 32 of these lipid alterations persist to 3 months, with remodelling of the lipid signature at the dorsal pole. 14 new alterations occur concurrent with histological changes. Changes in peroxisome-dependent lipids detected by liquid chromatography tandem mass spectrometry (reduced docosahexanoic acid and increased very long chain lysophosphatidylcholines) are exacerbated over time. This study represents the first characterization of RPE in any animal model of ZSD, and the first in situ lipid analysis in any peroxisome-deficient tissue. Our findings reveal candidate lipid drivers that could be targeted to alleviate RD progression in ZSD, as well as candidate biomarkers that could be used to evaluate retinopathy progression and response to therapy.

pathology↗

bioRxiv2023

Structure guided mutagenesis of Henipavirus Receptor Binding Proteins reveals molecular determinants of receptor usage and antibody binding epitopes

Nipah virus (NiV) is a highly lethal, zoonotic henipavirus (HNV) that causes respiratory and neurological signs and symptoms in humans. Similar to other paramyxoviruses, HNVs mediate entry into host cells through the concerted actions of two surface glycoproteins: a receptor binding protein (RBP) that mediates attachment and a fusion glycoprotein (F) that triggers fusion in an RBP-dependent manner. NiV uses ephrin-B2 (EFNB2) and ephrin-B3 (EFNB3) as entry receptors. Ghana virus (GhV), a novel HNV identified in a Ghanaian bat, use EFNB2 but not EFNB3. In this study, we employ a structure-informed approach to identify receptor interfacing residues and systematically introduce GhV-RBP residues into a NiV-RBP backbone to uncover the molecular determinants of EFNB3 usage. We reveal two regions that severely impair EFNB3 binding by NiV-RBP and EFNB3-mediated entry by NiV pseudotyped viral particles. Further analyses uncovered two point mutations (NiVN557SGhV and NiVY581TGhV) pivotal for this phenotype. Moreover, we identify NiV interaction with Y120 of EFNB3 as important for usage of this receptor. Beyond these EFNB3-related findings, we reveal two domains that restrict GhV binding of EFNB2, identify the HNV-head as an immunodominant target for polyclonal and monoclonal antibodies, and describe putative epitopes for GhV and NiV-specific monoclonal antibodies. Cumulatively, the work presented here generates useful reagents and tools that shed insight to residues important for NiV usage of EFNB3, reveals regions critical for GhV binding of EFNB2, and describes putative HNV antibody binding epitopes.

molecular biology↗

bioRxiv2019

A key region of molecular specificity orchestrates unique ephrin-B1 utilization by Cedar virus

The prototypic henipaviruses (HNV), Hendra (HeV) and Nipah (NiV), are emergent zoonotic pathogens responsible for frequent and fatal outbreaks of severe disease in domestic animals and humans. The HNV attachment glycoprotein (G) is a critical determinant of host-species and cell-type tropism. Utilization of highly conserved B-type ephrin ligands as functional entry receptors engenders HNVs with a broad permissive host range, accounts for zoonotic spillover, and is closely aligned with observed disease pathologies. Recent studies have uncovered numerous divergent clades of HNVs globally. Cedar virus (CedV), the closest relative of HeV and NiV identified to date, can establish experimental infections, yet has not been observed to cause overt disease. While the apathogenic phenotype may be attributed to a lack of P-gene derived interferon antagonists, the V and W accessory proteins, additional determinants of differential HNV pathobiology could be involved. Here, through comparative functional and structural analysis of CedV-G, we characterize molecular interactions critical to viral entry. We demonstrate that CedV possesses a unique cellular entry receptor repertoire which, in addition to functional utilization of the common HNV receptor, ephrin-B2, includes the hitherto uncharacterized interaction with ephrin-B1. Crystal structures reveal a conserved recognition mode between diverse HNV-G proteins and their distinct ephrin receptors and identify a region of molecular specificity within CedV-G that is a key determinant of ephrin selectivity. This work provides a platform for understanding the functional diversity and varied receptor tropism characteristics of HNV glycoproteins that will facilitate assessment of the pathogenic potential and transmissibility of newly discovered and uncharacterized HNVs.

microbiology↗

bioRxiv2017

Molecular evolution, diversity and adaptation of H7N9 influenza A viruses in China

A novel H7N9 avian influenza virus has caused five human epidemics in China since 2013. The substantial increase in prevalence and the emergence of antigenically divergent or highly pathogenic (HP) H7N9 strains during the current outbreak raises concerns about the epizootic-potential of these viruses. Here, we investigate the evolution and adaptation of H7N9 by combining publicly available data with newly generated virus sequences isolated in Guangdong between 2015-2017. Phylogenetic analyses show that currently-circulating H7N9 viruses belong to distinct lineages with differing spatial distributions. Using ancestral sequence reconstruction and structural modelling we have identified parallel amino-acid changes on multiple separate lineages. Furthermore, we infer mutations in HA primarily occur at sites involved in receptor-recognition and/or antigenicity. We also identify seven new HP strains, which likely emerged from viruses circulating in eastern Guangdong around March 2016 and is further associated with a high rate of adaptive molecular evolution.

evolutionary biology↗