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Biology subjects

Fiegl, M.

Publications and source records attributed to Fiegl, M..

2 recordsLinked to original sources

Innate immune responses to Plasmodium falciparum disrupt the blood-brain barrier

Plasmodium falciparum accumulation at the blood-brain barrier (BBB) is a hallmark of cerebral malaria, a life-threatening complication. Conversely, the contribution of the immune response to vascular injury has long been debated. Here, we studied the role of innate immune cells as potential effectors of vascular damage using a human in vitro 3D-BBB model. Parasite-stimulated immune cells from malaria-naive donors increased adhesion to microvessels, at least partly through LFA-1. This caused barrier disruption and inflammatory activation of BBB cells. Secretion of TNF-, IFN-{gamma}, and granzyme B by monocytes, NK and {gamma}{delta} T cells correlated with vascular injury, and accumulation of immune cells was required for local barrier damage. Our computational analysis disentangled pathogenic mechanisms driven specifically by either P. falciparum parasite or immune cells, as well as shared pathways. These findings demonstrate how vascular-immune interactions may contribute to vascular injury in cerebral malaria and point towards the potential of immunomodulatory therapeutics.

immunology↗

Toll-like receptor 3 orchestrates a conserved mechanism of heart regeneration

The humans heart responds to tissue damage with persistent fibrotic scarring. Unlike humans, zebrafish can repair cardiac injury and re-grow heart tissue throughout life. Recently, Toll-like receptor 3 (Tlr3) was identified as an important mediator of cardiac regeneration in neonatal mice. However, no functional analysis of tlr3 knock-out mutant zebrafish in respect to cardiac regeneration has yet been performed. We hypothesize that TLR3 signalling plays a central, conserved role in driving cardiac regeneration upon injury. Therefore, we focused on tlr3 mediated cardiac regeneration in zebrafish, ultimately discovering an evolutionary conserved mechanism of heart repair. Using histological, behavioural, and RNA-Sequencing analysis, we uncovered a conserved mechanism of tlr3 mediated cardiac repair after myocardial injury. Upon myocardial cryoinjury subjection, survival is decreased in tlr3-/- fish as compared to wildtype controls. Tlr3-/- zebrafish fail to recruit immune cells to the injured ventricle, resulting in impaired DNA repair and transcriptional reprogramming of cardiomyocytes. Mechanistically, we uncover an evolutionary conserved mechanism of tlr3 activation in fibroblasts promoting monocyte migration towards an injured ventricular area. Our data reveal tlr3 as a novel therapeutic target to promote cardiac regeneration. Every experiment including human participants has been approved by the ethics committee of the Medical University of Innsbruck (Ref. Nr.: 1262/2023). All experiments including the use of laboratory animals have been approved by the federal ministry of education, science, and research of Austria (Ref. Nr.: 2020-0.345.504).

molecular biology↗