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Detection of Toxin Translocation into the Host Cytosol by Surface Plasmon Resonance
Published on: January 3, 2012
Endotoxin causes functional endoplasmic reticulum failure, possibly mediated by mitochondria.
Andrey V Kozlov1, J Catharina Duvigneau, Ingrid Miller
1Ludwig Boltzmann Institute for Experimental and Clinical Traumatology in the AUVA Research Center, Donaueschingenstr. 13, 1200 Vienna, Austria. andrey.kozlov@lbitrauma.org
Biochimica Et Biophysica Acta
|March 31, 2009
Summary
Endotoxin exposure causes endoplasmic reticulum (ER) stress and functional failure in rat livers, indicated by impaired protein processing and detoxification. This ER dysfunction may contribute to organ damage during severe inflammatory responses.
Area of Science:
- Hepatology
- Cellular Biology
- Toxicology
Background:
- Inflammatory responses can trigger endoplasmic reticulum (ER) stress and the unfolded protein response (UPR).
- The UPR can either restore ER function or initiate apoptosis.
- Endotoxin, a potent inflammatory mediator, is implicated in organ dysfunction.
Purpose of the Study:
- To investigate the effects of endotoxin (lipopolysaccharide, LPS) on ER function in rat livers.
- To determine the pathway through which LPS induces ER stress and potential failure.
- To assess the link between ER dysfunction and organ damage.
Main Methods:
- Administration of LPS to rats.
- Histological and electron microscopy examination of liver tissue.
- Analysis of ER stress markers at mRNA and protein levels (XBP1, GRP78).
- Assessment of apoptotic markers and cytochrome P450 (p450) activity.
- Biochemical analysis of ER-associated proteins.
Main Results:
- LPS induced ER stress, evidenced by upregulated XBP1 and GRP78 mRNA, but downregulated GRP78 protein.
- Electron microscopy revealed dilated ER around mitochondria.
- A pre-apoptotic state was observed, but apoptosis was not fully executed.
- Detoxification activity of p450 enzymes decreased, and protein folding/transport were impaired.
- No significant liver necrosis was observed histologically.
Conclusions:
- LPS induces functional ER failure in rat livers, potentially via a mitochondrion-dependent pathway.
- Impaired protein processing, folding, transport, and detoxification suggest significant ER dysfunction.
- This functional ER failure may be a key mechanism underlying organ dysfunction in endotoxemia.
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