Human-specific staphylococcal virulence factors enhance pathogenicity in a humanised zebrafish C5a receptor model

Unravelling the Programmed Inflammation and Tissue Repair by a Multipotential Antimicrobial K21 Silane

AIMS AND OBJECTIVES

To examine if a novel antimicrobial silane K21 can alter macrophage polarisation and affect fibroblast proliferation by deciphering the molecular pathways for programmed healing using a combined in vitro and in vivo (animal) burn model.

MATERIALS AND METHODS

An injectable silane-based antimicrobial aimed to modulate macrophage polarisation was manufactured. Experimental analysis included colorimetric cell migration assays on gingival fibroblasts, macrophage phagocytosis characterisation, immunofluorescence staining, triacylglycerol accumulation within macrophages by LCMS, cellular metabolic/proliferation assays, macrophage exposure quantification with morphology assessment using FE-SEM, Raman spectral analysis, RNA isolation for relative gene expression and animal study model to morphometrically and microscopically analyse partial thickness burn wound healing under QAS/K21.

RESULTS

M1 and M2 polarisation both appeared exaggerated under QAS/K21 treatment. The wounds treated with K21 had depicted accelerated healing as compared to control (P < .05) in dorsal skin of rabbits. Relative gene expression results demonstrate reduced cytokine and anti-inflammatory response under the influence of K21. While M1 expression, TG accumulation, and associated characterisations demonstrate the programmed inflammatory potential of K21.

CONCLUSION

the antimicrobial and reparative efficacy of K21 silane aids in programmed inflammation for enhanced tissue healing and repair.

Molecular Actors of Inflammation and Their Signaling Pathways: Mechanistic Insights from Zebrafish

Inflammation is a hallmark of the physiological response to aggressions. It is orchestrated by a plethora of molecules that detect the danger, signal intracellularly, and activate immune mechanisms to fight the threat. Understanding these processes at a level that allows to modulate their fate in a pathological context strongly relies on in vivo studies, as these can capture the complexity of the whole process and integrate the intricate interplay between the cellular and molecular actors of inflammation. Over the years, zebrafish has proven to be a well-recognized model to study immune responses linked to human physiopathology. We here provide a systematic review of the molecular effectors of inflammation known in this vertebrate and recapitulate their modes of action, as inferred from sterile or infection-based inflammatory models. We present a comprehensive analysis of their sequence, expression, and tissue distribution and summarize the tools that have been developed to study their function. We further highlight how these tools helped gain insights into the mechanisms of immune cell activation, induction, or resolution of inflammation, by uncovering downstream receptors and signaling pathways. These progresses pave the way for more refined models of inflammation, mimicking human diseases and enabling drug development using zebrafish models.