Biology subjects

Haas, P.-J.

Publications and source records attributed to Haas, P.-J..

7 recordsLinked to original sources

bioRxiv2024

KlebPhaCol: A community-driven resource for Klebsiella research identified a novel gut phage order associated with the human gut

The growing threat of multidrug-resistant Klebsiella pneumoniae, coupled with its role in gut colonisation, has intensified the search for new treatments, including bacteriophage therapy. Despite increasing documentation of Klebsiella-targeting phages, clinical applications remain limited, with key phage-bacteria interactions still poorly understood. A major obstacle is fragmented access to well-characterised phage-bacteria pairings, restricting the collective advancement of therapeutic and mechanistic insights. To address this gap, we created the Klebsiella Phage Collection (KlebPhaCol), an open-source resource comprising 53 phages and 74 Klebsiella isolates, all fully characterised. These phages span five families - including a novel order, Felixvirales, associated with the human gut - and target 27 sequence types (including ST258, ST11, ST14) and 28 capsular-locus types (including KL1 and KL2), across six Klebsiella species. Freely accessible at www.klebphacol.org, KlebPhaCol invites the scientific community to both use and contribute to this resource, fostering collaborative research and a deeper understanding of Klebsiella-phage interactions beyond therapeutic use.

microbiology↗

bioRxiv2024

Longitudinal fluctuations in protein concentrations and higher-order structures in the plasma proteome of kidney failure patients subjected to a kidney transplant

Using proteomics and complexome profiling we evaluated over a period of a year longitudinal variations in the plasma proteome of kidney failure patients, prior to and after a kidney transplantation, comparing this data with two healthy controls. The post-transplant period was complicated by numerous bacterial infections, resulting in dramatic changes in the plasma proteome, mostly related to an acute phase condition. As positive acute phase proteins, being elevated upon inflammation, we observed the well-described C-reactive protein (CRP) and Serum Amyloid A (SAA1 and SAA2), but our analyses added to that Fibrinogen (FGA, FGB and FGG), Haptoglobin (HP), Leucine-rich alpha-2-glycoprotein (LRG1), Lipopolysaccharide- binding protein (LBP), Alpha-1-antitrypsin (SERPINA1), Alpha-1-antichymotrypsin (SERPINA3), Protein S100 (S100A8, S100A9), Complement protein C4, C4b-binding protein alpha chain (C4BPA), Complement factor B (CFB) and Monocyte differentiation antigen CD14. As negative acute phase proteins, being downregulated upon inflammation, we identified the well-documented Serotransferrin (TF) and Transthyretin (TTR), but add on to that Kallistatin (SERPINA4), Heparin cofactor 2 (SERPIND1), Inter-alpha-trypsin inhibitor heavy chain H1 and H2 (ITIH1, ITIH2). For a patient with the most severe acute phase response, we furthermore performed plasma complexome profiling by SEC-LC-MS on all longitudinal samples. We observe that several plasma proteins displaying alike concentration patterns, co- elute and putatively form macromolecular complexes. These include a) FGA, FGB and FGG (as expected, b) ITIH1 and ITIH2, c) HP together with Hemoglobin (HB), d) the small acute phase biomarker proteins SAA1 and SAA2 with the Apolipoproteins A-I, A-II, A-IV (APOA1, APOA2, APOA4). By complexome profiling we expose how SAA1 and SAA2 become incorporated into high-density lipid particles, thereby replacing partly APOA1 and APOA4. Overall, our data highlight that the combination of in-depth longitudinal plasma proteome and complexome profiling can shed further light on the correlated variations in the abundance of several plasma proteins upon inflammatory events.

molecular biology↗

bioRxiv2023

Direct mass spectrometry-based detection and antibody sequencing of Monoclonal Gammopathy of Undetermined Significance from patient serum - a case study.

Monoclonal gammopathy of undetermined significance (MGUS) is a plasma cell disorder, characterized by the presence of a predominant monoclonal antibody (i.e., M-protein) in serum, without clinical symptoms. Here we present a case study in which we detect MGUS by liquid-chromatography coupled with mass spectrometry (LC-MS) profiling of IgG1 in human serum. We detected a Fab-glycosylated M-protein and determined the full heavy and light chain sequences by bottom-up proteomics techniques using multiple proteases, further validated by top-down LC-MS. Moreover, the composition and location of the Fab-glycan could be determined in CDR1 of the heavy chain. The outlined approach adds to an expanding mass spectrometry-based toolkit to characterize monoclonal gammopathies such as MGUS and multiple myeloma, with fine molecular detail. The ability to detect monoclonal gammopathies and determine M-protein sequences straight from blood samples by mass spectrometry provides new opportunities to understand the molecular mechanisms of such diseases.

immunology↗

bioRxiv2022

Accumulation of defense systems drives panphage resistance in Pseudomonas aeruginosa

Prokaryotes encode multiple distinct anti-phage defense systems in their genomes. However, the impact of carrying a multitude of defense systems on phage resistance remains unclear, especially in a clinical context. Using a collection of antibiotic-resistant clinical strains of Pseudomonas aeruginosa and a broad panel of phages, we demonstrate that defense systems contribute substantially to defining phage host range and that overall phage resistance scales with the number of defense systems in the bacterial genome. We show that many individual defense systems are specific to phage genera, and that defense systems with complementary phage specificities co-occur in P. aeruginosa genomes likely to provide benefits in phage-diverse environments. Overall, we show that phage-resistant phenotypes of P. aeruginosa with at least 19 phage defense systems exist in the populations of clinical, antibiotic-resistant P. aeruginosa strains.

microbiology↗

bioRxiv2022

LaeA-dependent production of small molecules of Aspergillus niger that compete with specific antibodies that bind to human immune receptors

Microorganisms secrete a variety of compounds into their environment such as proteins, carbohydrates, and secondary metabolites. These molecules play diverse roles in the interaction of microbes with their abiotic and biotic environment. Little is known about secreted fungal molecules mediating immune evasion. Here we screened culture media of three Aspergilli to assess whether these fungi secrete molecules that can compete with specific antibodies that bind to human immune receptors. Culture media of Aspergillus fumigatus Af293, Aspergillus tubingensis CBS 133792 and the non-acidifying mutant strain Aspergillus niger D15#26 contained components that showed competition for binding to a total of 13 receptors, of which PSGL-1, CXCR1, and CXCR2, were shared between the three species. Filtration experiments showed that most, if not all, interacting components were [≤] 3 kDa. Production of the components that competed with antibodies to bind to CD88 and CXCR2 was shown to be regulated by LaeA. The component(s) that competed for binding to CXCR1 was not only produced in the non-acidifying strain Aspergillus niger D15#26 but also in the non-acidifying oahA deletion strain of Aspergillus niger. Together, these data show that Aspergillus species might produce small molecules that interact with human immune receptors.

microbiology↗

bioRxiv2021

Genomic characterization of four novel bacteriophages infecting the clinical pathogen Klebsiella pneumoniae

Bacteriophages are an invaluable source of novel genetic diversity. Sequencing of phage genomes can reveal new proteins with potential uses as biotechnological and medical tools, and help unravel the diversity of biological mechanisms employed by phages to take over the host during viral infection. Aiming to expand the available collection of phage genomes, we have isolated, sequenced, and assembled the genome sequences of four phages that infect the clinical pathogen Klebsiella pneumoniae: vB_KpnP_FBKp16, vB_KpnP_FBKp27, vB_KpnM_FBKp34, and Jumbo phage vB_KpnM_FBKp24. The four phages show very low (0-13%) identity to genomic phage sequences deposited in the Genbank database. Three of the four phages encode tRNAs and have a GC content very dissimilar to that of the host. Importantly, the genome sequences of the phages reveal potentially novel DNA packaging mechanisms as well as distinct clades of tubulin spindle and nucleus shell proteins that some phages use to compartmentalize viral replication. Overall, this study contributes to uncovering previously unknown virus diversity, and provides novel candidates for phage therapy applications against antibiotic-resistant K. pneumoniae infections.

microbiology↗

bioRxiv2018

Staphylococcal superantigen-like protein 13 activates neutrophils via Formyl Peptide Receptor 2

Staphylococcal Superantigen-Like (SSL) proteins, one of major virulence factor families produced by Staphylococcus aureus, were previously demonstrated to be immune evasion molecules that interfere with a variety of innate immune defenses. However, in contrast to these characterized SSLs, that inhibit immune functions, we show that SSL13 is a strong activator of neutrophils via the formyl-peptide receptor 2 (FPR2). Moreover, our data show that SSL13 acts as a chemoattractant, induces degranulation and oxidative burst in neutrophils. As with many other staphylococcal immune evasion proteins, SSL13 shows a high degree of human specificity. SSL13 is not able to efficiently activate mouse neutrophils, hampering in vivo experiments.\n\nIn conclusion, SSL13 is a neutrophil chemoattractant and activator that acts via the FPR2. Therefore, SSL13 is a unique SSL member that does not belong to the immune evasion class, but is a pathogen alarming molecule.

microbiology↗