Biology subjects

Eaton, C. J.

Publications and source records attributed to Eaton, C. J..

4 recordsLinked to original sources

bioRxiv2024

Identification of novel plasma proteomic biomarkers of Dupuytren Disease

Dupuytren Disease (DD) is a chronic progressive disease that can cause disabling hand deformities. The most common treatments have either high complication rates or high early recurrence rates. Dupuytren lacks a staging biomarker profile to inform the development of preventive therapeutics to improve long-term outcomes. This multi-omic study aimed to create a DD blood proteomic biomarker profile by comparing DD plasma with that of a healthy control group. We measured circulating collagen metabolism peptides and found normal Collagen I synthesis but impaired Collagen I degradation in DD. We measured 6995 serum protein aptamers and identified 68 proteins that showed statistically significant differences compared with the control group. We developed two Diagnostic Proteomic Risk Scores (DPRS) based on hypothesis-free and hypothesis-based analyses. In independent data, our hypothesis-free and hypothesis-based DPRS distinguished Dupuytren from control subjects with accuracies of 76.5% and 70.6%, respectively. Our hypothesis-based DPRS also distinguished DD subjects with different disease progression rates by age at their first corrective procedure (p=0.0018). This pilot study is the first to provide evidence to suggest that Collagen I accumulation in DD results from impaired degradation rather than increased collagen synthesis. It also describes novel DPRS that have potential use as diagnostic and staging biomarker panels for Dupuytren disease.

molecular biology↗

bioRxiv2020

A homologue of the mammalian tumour suppressor protein PTEN is a functional lipid phosphatase and required for chemotaxis in filamentous fungi

Phosphoinositides (PI) are essential components of eukaryotic membranes and function in a large number of signalling processes. While lipid second messengers are well studied in mammals and yeast, their role in filamentous fungi is poorly understood. We used fluorescent PI-binding molecular probes to localise the phosphorylated phosphatidylinositol species PI[3]P, PI[3,5]P2, PI[4]P and PI[4,5]P2 in hyphae of the endophyte Epichloe festucae in axenic culture and during interaction with its grass host Lolium perenne. We also analysed the roles of the phosphatidylinositol-4-phosphate 5-kinase MssD and the predicted phosphatidylinositol-3,4,5-triphosphate 3-phosphatase TepA, a homologue of the mammalian tumour suppressor protein PTEN. Deletion of tepA in E. festucae and in the root-infecting tomato pathogen Fusarium oxysporum had no impact on growth in culture or the host interaction phenotype. However, this mutation did uncover the presence of PI[3,4,5]P3 in septa of E. festucae and showed that TepA is required for chemotropism in F. oxysporum. The identification of PI[3,4,5]P3 in septa of{Delta} tepA strains suggests that filamentous fungi are able to generate PI[3,4,5]P3 using an alternative biosynthetic pathway and that fungal PTEN homologues are functional lipid phosphatases. The F. oxysporum chemotropism defect demonstrates a conserved role of PTEN homologues in chemotaxis across protists, fungi and mammals.

cell biology↗

bioRxiv2019

Reprogramming of the apoplast metabolome of Lolium perenne upon infection with the mutualistic symbiont Epichloë festucae

Epichloe festucae is an endophytic fungus that forms a mutualistic symbiotic association with Lolium perenne. Here we analysed how the metabolome of the ryegrass apoplast changed upon infection of this host with sexual and asexual isolates of E. festucae. A metabolite fingerprinting approach was used to analyse the metabolite composition of apoplastic wash fluid from non-infected and infected L. perenne. Metabolites enriched or depleted in one or both of these treatments were identified using a set of interactive tools. A genetic approach in combination with tandem mass spectrometry was used to identify a novel product of a secondary metabolite gene cluster. Metabolites likely to be present in the apoplast were identified using the MarVis Pathway in combination with the BioCyc and KEGG databases, and an in-house Epichloe metabolite database. We were able to identify the known endophyte-specific metabolites, peramine and epichloecyclins, as well as a large number of unknown markers. To determine whether these methods can be applied to the identification of novel Epichloe-derived metabolites, we deleted a gene encoding a NRPS (lgsA) that is highly expressed in planta. Comparative mass spectrometric analysis of apoplastic wash fluid from wild-type- versus mutant- infected plants identified a novel Leu/Ile glycoside metabolite present in the former.

microbiology↗

bioRxiv2019

Phosphatidic acid produced by phospholipase D is required for hyphal cell-cell fusion and fungal-plant symbiosis

Although lipid signaling has been shown to serve crucial roles in mammals and plants, little is known about this process in filamentous fungi. Here we analyse the contribution of phospholipase D (PLD) and its product phosphatidic acid (PA) in hyphal morphogenesis and growth of Epichloe festucae and Neurospora crassa, and in the establishment of a symbiotic interaction between E. festucae and Lolium perenne. Growth of E. festucae and N. crassa PLD deletion strains in axenic culture, and for E. festucae in association with L. perenne, were analysed by light-, confocal- and electron microscopy. Changes in PA distribution were analysed in E. festucae using a PA biosensor and the impact of these changes on endocytic recycling and superoxide production investigated. We found that E. festucae PldB and the N. crassa ortholog, PLA-7, are required for polarized growth, cell fusion and ascospore development, whereas PldA/PLA-8 are dispensable for these functions. Exogenous addition of PA rescues the cell-fusion phenotype in E. festucae. PldB is also crucial for E. festucae to establish a symbiotic association with L. perenne. This study identifies a new component of the cell-cell communication and cell fusion signaling network that controls hyphal morphogenesis and growth in filamentous fungi.

genetics↗