Biology subjects

Luu, L. D. W.

Publications and source records attributed to Luu, L. D. W..

5 recordsLinked to original sources

bioRxiv2026

First inhibitor of a bacterial two-partner secretion system.

Two-partner secretion system transporter proteins (TpsB) are widely conserved across Gram-negative pathogens. TpsB family proteins secrete exoprotein virulence factors that perform a myriad of functions such as adhesion and immune modulation. Despite their incredible importance in bacterial infectious disease, TpsB inhibitors have not yet been discovered. Here, we describe a potent inhibitor of FhaC, a TpsB protein produced by Bordetella spp. FhaC secretes the exoprotein FhaB that is essential for the establishment of whooping cough. We designed a peptide called P1 that we predicted would prevent substrate binding and lock FhaC in a secretion-inactive state. Simulations and biochemical assays supported our hypothesis and identified interactions important for P1 binding to FhaC. Strikingly, we observed that the peptide strongly inhibited FhaB secretion from clinical isolates and broadly reduced correlates of virulence. Together, this work provides a strong case for further development of a novel class of anti-TpsB anti-virulence compounds.

biochemistry↗

bioRxiv2024

Proteomic comparison of epidemic Australian Bordetella pertussis biofilm cells

Bordetella pertussis causes whooping cough, a severe respiratory infectious disease. Studies have compared the currently dominant single nucleotide polymorphism (SNP) cluster I (pertussis toxin promoter allele, ptxP3) and previously dominant SNP cluster II (ptxP1) strains as planktonic cells. Since biofilm formation is linked with B. pertussis pathogenesis in vivo, this study compared the biofilm formation capabilities of representative strains of cluster I and cluster II. Confocal laser scanning microscopy found that the cluster I strain had a denser biofilm structure compared to the cluster II strain. Differences in protein expression of the biofilm cells were then compared using Tandem Mass Tagging (TMT) and high-resolution multiple reaction monitoring (MRM-hr). In total, 1453 proteins were identified of which 40 proteins had significant differential expression between the two strains in biofilm conditions. Of particular interest was a large increase in expression of energy metabolism proteins (cytochrome proteins PetABC and BP3650) in the cluster I strain. When the expression of these proteins was compared between 6 additional strains from each cluster, it was found that the protein expression varied between all strains. These findings suggest that there are large levels of individual proteomic diversity between B. pertussis strains in biofilm conditions despite the highly conserved genome of the species. Overall, this study revealed visual differences in biofilm structure between B. pertussis strains and highlighted strain specific variation in protein expression that dominate potential cluster specific changes that may be linked with the dominance of cluster I strains. ImportanceBordetella pertussis causes whooping cough. The currently circulating cluster I strains have taken over previously dominant cluster II strains. It is important to understand the reasons behind the evolution to develop new strategies against the pathogen. Recent studies have shown that B. pertussis can form biofilms during infection. This study compared the biofilm formation capabilities of a cluster I and a cluster II strain and identified visual differences in the biofilms. The protein expression between these strains grown in biofilms were compared and proteins identified with varied expression were measured with additional strains from each cluster. It was found that despite the highly conserved genetics of the species, there was varied protein expression between the additional strains. This study highlights that strain specific variation in protein expression during biofilm conditions that may dominate the cluster specific changes that may be linked to the dominance of cluster I strains.

microbiology↗

bioRxiv2022

Integrating proteomic data with metabolic modelling provides insight into key pathways of Bordetella pertussis biofilms

Pertussis, commonly known as whooping cough is a severe respiratory disease caused by the bacterium, Bordetella pertussis. Despite widespread vaccination, pertussis resurgence has been observed globally. The development of the current acellular vaccine (ACV) has been based on planktonic studies. However, recent studies have shown that B. pertussis readily forms biofilms. A better understanding of B. pertussis biofilms is important for developing novel vaccines that can target all aspects of B. pertussis infection. This study compared the proteomic expression of biofilm and planktonic B. pertussis cells to identify key changes between the conditions. Major differences were identified in virulence factors including an upregulation of toxins (adenylate cyclase toxin and dermonecrotic toxin) and downregulation of pertactin and type III secretion system proteins in biofilm cells. To further dissect metabolic pathways that are altered during the biofilm lifestyle, the proteomic data was then incorporated into a genome scale metabolic model using the integrative metabolic analysis tool (iMAT). The analysis revealed that planktonic cells utilised the glyoxylate shunt while biofilm cells completed the full tricarboxylic acid cycle. Differences in processing aspartate, arginine and alanine were identified as well as unique export of valine out of biofilm cells which may have a role in inter-bacterial communication and regulation. Finally, increased polyhydroxybutyrate accumulation and superoxide dismutase activity in biofilm cells may contribute to increased persistence during infection. Taken together, this study modelled major proteomic and metabolic changes that occur in biofilm cells which helps lay the groundwork for further understanding B. pertussis pathogenesis.

microbiology↗

bioRxiv2022

Genomic dissection of the microevolution of Australian epidemic Bordetella pertussis

Whooping cough (pertussis) is a highly contagious respiratory disease caused by the bacterium Bordetella pertussis. Despite high vaccine coverage, pertussis has re-emerged in many countries and caused two large epidemics in Australia since 2007. Here, we undertook a genomic and phylogeographic study of 385 Australian B. pertussis isolates collected from 2008 to 2017. The Australian B. pertussis population was found to be composed of mostly ptxP3 strains carrying different fim3 alleles, with ptxP3-fim3A genotype expanded far more than ptxP3-fim3B. Within the former, there were six co-circulating epidemic lineages (EL1 to EL6). The multiple ELs emerged, expanded, and then declined at different time points over the two epidemics, likely driven by immune selection from pertussis vaccination and natural infection in addition to local and global transmission events. Both hard and soft selective sweeps through vaccine selection pressures determined the current B. pertussis population dynamics. Relative risk analysis found that once a new B. pertussis lineage emerged, it was more likely to spread locally within the first 1.5 years. However, after 1.5 years, any new lineage was likely to expand to a wider region and became no longer spatially structured across the country. Phylogenetic analysis revealed the expansion of ptxP3 strains was also associated with replacement of the type III secretion system allele bscI1 with bscI3. This study advanced our understanding of the epidemic population structure and spatial and temporal dynamics of B. pertussis in a highly immunised population.

microbiology↗

bioRxiv2020

Temporal ordering of omics and multiomic events inferred from time series data

Temporal changes in omics events can now be routinely measured, however current analysis methods are often inadequate, especially for multiomics experiments. We report a novel analysis method that can infer event ordering at better temporal resolution than the experiment, and integrates omic events into two concise visualizations (event maps and sparklines). Testing our method gave results well-correlated with prior knowledge and indicated it streamlines analysis of time-series data.

bioinformatics↗