Biology subjects

Salgado-Pabon, W.

Publications and source records attributed to Salgado-Pabon, W..

7 recordsLinked to original sources

bioRxiv2026

A TSST 1 structural motif disrupts endothelial programs required for vascular regeneration.

Staphylococcus aureus causes profound vascular damage during infection, where it inflicts vascular injury across organs and generates lesions that fail to heal. Superantigens are major virulence factors in S. aureus infections, yet their direct effects on vascular repair remain unclear. We provide evidence that TSST-1 disrupts endothelial regeneration through coordinated mechanisms. TSST-1 interferes with collective directed migration, impairing endothelial cell directional persistence and preventing re-endothelialization in vitro. These defects stem from cytoskeletal disorganization, characterized by stress fiber accumulation and loss of lamellipodia, and broad suppression of motility-associated secreted factors. In an ex vivo aortic ring assay, TSST-1 suppresses angiogenic sprouting and generates dysmorphic vascular networks. Proteomic profiling reveals a shift toward matrix rigidity, adhesion stabilization, and overall suppression of angiogenesis. These activities map to a conserved dodecapeptide motif. Hence, TSST-1 suppression of vascular repair may convert sites of tissue injury into persistently non-healing niches suited for S. aureus persistence.

cell biology↗

bioRxiv2024

A microphysiological system of sterile injury demonstrates neutrophil reverse migration via macrophage-derived extracellular vesicle crosstalk.

Persistent neutrophilic inflammation can lead to tissue damage and chronic inflammation, contributing to non-healing wounds. The resolution phase of neutrophilic inflammation is critical to preventing tissue damage, as observed in diseases characterized by influx of neutrophils such as atherosclerosis and non-healing wounds. Animal models have provided insight into resolution of neutrophilic inflammation via efferocytosis and reverse migration (rM); however, species-specific differences and complexity of innate immune responses make translation to humans challenging. Thus, there is a need for in vitro systems that can elucidate mechanisms of resolution of human neutrophilic inflammation. Here, we developed a human microphysiological system (MPS) to mimic an inflammatory sterile injury (SI) microenvironment to study the role of macrophage derived extracellular vesicles (M-EVs) in determining the resolution of inflammation via neutrophil rM. The MPS integrates a human umbilical vein endothelial cell (HUVEC) lined lumen, injury site spheroid, human neutrophils, macrophages and macrophage derived EVs to investigate the role of M-EVs in neutrophil rM in vitro. The key features of the MPS enabled us to demonstrate that EVs derived from macrophage subsets modulate migratory behavior in primary neutrophils differently in specific inflammatory microenvironments. Importantly, we identified a new mechanism underlying neutrophil rM via M-EV, where neutrophils exposed to M2-EV-derived IL-8 migrate away from the SI site upon reaching the site, using the SI MPS. Overall, our SI MPS system demonstrates a reverse migratory pattern in human primary neutrophils, advancing the study of the resolution of inflammation via M-EVs.

immunology↗

bioRxiv2022

IL-17C is a driver of damaging inflammation during Neisseria gonorrhoeae infection of human Fallopian tube

The human-restricted pathogen Neisseria gonorrhoeae ascends into the upper female reproductive tract to cause damaging inflammation within the Fallopian tubes (salpingitis) and pelvic inflammatory disease (PID), increasing the risk of infertility and life-threatening ectopic pregnancy. The loss of ciliated cells from the epithelium is thought to be both a consequence of inflammation and a cause of the associated adverse sequelae. However, the links between infection, inflammation, and ciliated cell extrusion remain unresolved. With the use of ex vivo cultures of human Fallopian tube paired with RNA sequencing we defined the tissue response to gonococcal challenge, identifying cytokine, chemokine, cell adhesion, and apoptosis related transcripts not previously recognized as potentiators of gonococcal PID. Unexpectedly, the cytokine IL-17C was one of the most highly induced genes. Yet, this cytokine has no previous association with gonococcal disease nor any sexually transmitted infection and thus it was selected for further characterization in our model. We show that human Fallopian tubes express the IL-17C receptor (IL-17RE) on the epithelial surface and that treatment with purified IL-17C induces pro-inflammatory cytokine secretion in addition to sloughing of the epithelium and generalized tissue damage. These results demonstrate a previously unrecognized but critical role of IL-17C in the damaging inflammation induced by gonococci in a human explant model of PID. SignificanceWe performed untargeted transcriptional analysis of the human Fallopian tube response to Neisseria gonorrhoeae. Focusing on one upregulated transcript not previously identified in any context of gonococcal infection, we show that the human Fallopian tube secretes the inflammation amplifying cytokine IL-17C in response to N. gonorrhoeae challenge. IL-17C treatment of human Fallopian tubes stimulated pro-inflammatory cytokine secretion and was sufficient to elicit epithelial cell pathologies characteristic of pelvic inflammatory disease (sloughing, exfoliation). Thus, we identify IL-17C as a previously unrecognized component of the host response to gonococci that promotes inflammation and tissue damage within the human Fallopian tube.

microbiology↗

bioRxiv2022

All Staphylococcus aureus bacteraemia strains have the potential to cause infective endocarditis: results of GWAS and experimental animal studies

Abstract and KeywordsO_ST_ABSAimsC_ST_ABSInfective endocarditis (IE) complicates 10-20% of Staphylococcus aureus bacteraemia (SAB). We aimed to determine whether IE strains of S. aureus are genotypically different or behave differently in experimental endocarditis models as compared to non-IE SAB strains. Methods and ResultsWe conducted a genome wide association study (GWAS) of 924 S. aureus genomes from IE (274) and non-IE (650) SAB patients, and tested a subset of strains in two experimental animal models of IE, one studying the early step of bacterial adhesion to inflamed mice valves, the second evaluating the local and systemic developmental process of IE on mechanically damaged rabbit valves. The genetic profile of S. aureus IE and non-IE SAB strains did not differ when considering single nucleotide polymorphisms, coding sequences and k-mers analyses in GWASs. In the inflammation-induced IE model in mice no difference was observed between IE and non-IE SAB strains both in adhesion to the cardiac valves and in the propensity to cause IE; in the mechanical IE-induced rabbit model, there was no difference between IE and non-IE SAB strains regarding vegetation size and CFU. ConclusionS. aureus isolates from SAB patients with and without IE were indistinguishable, by GWAS and by two in vivo models of IE. Thus, S. aureus strain variation is not the primary determinant of IE. Pending the possible identification of host factors predisposing to IE, all strains of S. aureus must be considered in patients as capable of causing this common, lethal infection once they have accessed the bloodstream. Translational PerspectiveStaphylococcus aureus endocarditis (IE) is a deadly complication of S. aureus bacteraemia (SAB). Beyond well-identified host related IE risk factors, whether bacterial features may influence the occurrence of IE in the course of bacteraemia remain elusive. We analysed the genomes of 924 S. aureus strains from IE and non-IE SAB and compared some in two in vivo IE models. We demonstrated that the propensity of S. aureus to cause IE in the course of bacteraemia does not depend on the intrinsic genetic or virulence factors of S. aureus. These findings are of importance for the management of S. aureus bacteraemia.

microbiology↗

bioRxiv2022

Vegetation formation in Staphylococcus aureus endocarditis inversely correlates with RNAIII and sarA expression in invasive clonal complex 5 (CC5) isolates

Infective endocarditis (IE) is one of the most feared and lethal diseases caused by Staphylococcus aureus. Once established, the infection is fast-progressing and tissue destructive. S. aureus of the clonal complex 5 (CC5) commonly cause IE yet are severely understudied. IE results from bacterial colonization and formation of tissue biofilms (known as vegetations) on injured or inflamed cardiac endothelium. S. aureus IE is promoted by adhesins, coagulases, and superantigens, with the exotoxins and exoenzymes likely contributing to tissue destruction and dissemination. Expression of the large repertoire of virulence factors required for IE and sequelae is controlled by complex regulatory networks. We investigated the temporal expression of the global regulators agr (RNAIII), rot, sarS, sarA, sigB, and mgrA in 8 invasive CC5 isolates and established intrinsic expression patterns associated with IE outcomes. We show that vegetation formation, as tested in the rabbit model of IE, inversely correlates with RNAIII and sarA expression during growth in Todd-Hewitt broth (TH). Large vegetations with severe sequelae arise from strains with high-level expression of colonization factors but slower transition towards expression of the exotoxins. Overall, strains proficient in vegetation formation, a hallmark of IE, exhibit lower expression of RNAIII and sarA. Simultaneous high expression of RNAIII, sarA, sigB, and mgrA is the one phenotype assessed in this study that fails to promote IE. Thus, RNAIII and sarA expression that provides for rheostat control of colonization and virulence genes, rather than an on and off switch, promote both vegetation formation and lethal sepsis.

microbiology↗

bioRxiv2021

Staphylococcus aureus β-toxin exerts anti-angiogenic effects by inhibiting re-endothelialization and neovessel formation

Staphylococcus aureus is the causative agent of numerous severe human infections associated with significant morbidity and mortality worldwide. S. aureus often targets the vascular endothelium to interfere with proper host responses during invasive infections. In this study, we provide evidence that S. aureus {beta}-toxin inhibits wound repair mechanisms in human endothelial cells by preventing cell proliferation and migration. These findings were confirmed in a rabbit aortic explant model where {beta}-toxin impedes sprout formation. Decreased cell proliferation was accompanied by decreased production of the angiogenic proteins endothelin-1, IGFBP-3, thrombospondin-1, TIMP-1, and TIMP-4. Meanwhile, inhibited wound repair was marked by increased HGF secretion from endothelial cells, likely a marker of endothelial cell damage. Together, these findings establish a mechanistic role for {beta}-toxin where it inhibits proper tissue repair processes that likely promote S. aureus infective niche.

microbiology↗

bioRxiv2019

Staphylococcal Enterotoxin C promotes Staphylococcus aureus Infective Endocarditis Independent of Superantigen Activity

The superantigen staphylococcal enterotoxin C (SEC) is critical for Staphylococcus aureus infective endocarditis (SAIE) in rabbits. Superantigenicity, its hallmark function, was proposed to be a major underlying mechanism driving SAIE but was not directly tested. With the use of S. aureus MW2 expressing SEC toxoids, we show that superantigenicity does not sufficiently account for vegetation growth, myocardial inflammation, and acute kidney injury in the rabbit model of native valve SAIE. These results highlight the critical contribution of an alternative function of superantigens to SAIE. In support of this, we provide evidence that SEC exerts anti-angiogenic effects by inhibiting branching microvessel formation in an ex vivo rabbit aortic ring model and by inhibiting endothelial cell expression of one of the most potent mediators of angiogenesis, VEGF-A. SECs ability to interfere with tissue re-vascularization and remodeling after injury serves as a mechanism to promote SAIE and its life-threatening systemic pathologies.

microbiology↗