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Lipopolysaccharides induce p8 mRNA expression in vivo and in vitro
Y F Jiang1, M I Vaccaro, F Fiedler
1Laboratoire de Recherche de Physiologie et Pathologie Digestives, INSERM U.315, 46 Bd de la Gaye, Marseille, 13009, France.
Abstract:
Systemic LPS endotoxin is associated with acute pancreatic damage. Whether damage results from direct interaction of LPS with pancreatic cells is unknown. We addressed that question by monitoring p8 expression in reponse to LPS, in vivo and in vitro, because overexpression of the p8 protein is a sensitive marker of pancreatic agression. For in vivo studies, rats were sacrificed at different times after a single intraperitoneal injection of LPS, and pancreas, liver, kidney, lung, brain, and intestine were processed for RNA preparation. In vitro, pancreatic acinar AR4-2J cells were cultivated with 0.1, 1, or 10 micrograms/ml LPS for 6, 12, or 24 h. p8 mRNA expression was monitored by Northern blotting. In vivo, it was strongly increased in the pancreas after 12 h of treatment and remained elevated after 24 h. It was also induced in kidney and liver, with a maximum at 6 and 12 h, respectively, but not in lung, brain, or intestine. In AR4-2J cells, basal p8 mRNA expression was very low and increased in a time- and dose-dependent manner after treatment with LPS. LPS-induced overexpression of p8 mRNA in vivo confirmed the adverse effect of endotoxemia on pancreas and its overexpression in vitro demonstrated a direct interaction of LPS with pancreatic cells.
Insights
Systemic lipopolysaccharide (LPS) endotoxin directly damages pancreatic cells, as shown by increased p8 protein expression in vivo and in vitro. This finding confirms LPS
Area of Science:
- Biochemistry
- Cell Biology
- Toxicology
Background:
- Systemic lipopolysaccharide (LPS) endotoxin is linked to acute pancreatic damage.
- The precise mechanism, specifically direct LPS interaction with pancreatic cells, remains unclear.
Purpose of the Study:
- To investigate whether lipopolysaccharide (LPS) directly interacts with pancreatic cells.
- To monitor p8 protein expression as a marker of pancreatic damage in response to LPS.
Main Methods:
- In vivo studies involved LPS injection in rats, with pancreas and other organs analyzed for p8 mRNA via Northern blotting.
- In vitro studies utilized pancreatic acinar AR4-2J cells treated with varying LPS concentrations and durations.
- p8 mRNA expression levels were quantified using Northern blotting in both experimental setups.
Main Results:
- In vivo, pancreatic p8 mRNA expression significantly increased post-LPS administration, indicating pancreatic stress.
- Kidney and liver also showed induced p8 mRNA expression, but lung, brain, and intestine did not.
- In vitro, pancreatic AR4-2J cells exhibited a time- and dose-dependent increase in p8 mRNA expression upon LPS exposure.
Conclusions:
- LPS directly interacts with pancreatic cells, leading to p8 mRNA overexpression.
- The study confirms the adverse effects of endotoxemia on the pancreas and establishes a direct cellular interaction model.