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Differential expression of the multiple forms of rat prekininogen mRNAs after acute inflammation
Abstract:
Responses of the rat liver prekininogen mRNAs after induction of acute inflammation were examined by blot-hybridization and S1 nuclease protection analyses with the aid of cDNA probes specific for rat kininogens. Marked changes in the relative levels of the low molecular weight (LMW) prekininogen mRNAs were observed after administration of Escherichia coli lipopolysaccharide, and the mRNA levels increased with a half-maximal dose of approximately 100 ng of lipopolysaccharide/100 g body weight. At maximum level of induction, the LMW prekininogen mRNAs comprised about 1% of total liver mRNA, thus representing a major component of the liver mRNA in the acutely inflamed rat. Differences in the inflammatory responses of various forms of the prekininogen mRNAs were then investigated by S1 nuclease protection analysis with the use of three different cDNA probes, each specific for either K-prekininogen or two types of T-prekininogens. Both of the T-prekininogen mRNAs increased progressively during the first 24 h after induction of inflammation, and at maximum level of induction, these two mRNAs increased about 10- and 13-fold over their normal level. In contrast, neither of the high molecular weight and LMW K-prekininogen mRNAs exhibited such an increase after induction of inflammation. Thus, the expressions of the rat T- and K-prekininogen mRNAs are differentially regulated in response to the induction of acute inflammation.
Insights
Acute inflammation significantly increases rat liver T-prekininogen messenger RNAs (mRNAs), while K-prekininogen mRNAs remain unchanged. This highlights differential regulation of kininogen gene expression during inflammation.
Area of Science:
- Biochemistry
- Molecular Biology
- Immunology
Background:
- Kininogens are precursors to kinins, involved in inflammation and blood pressure regulation.
- Understanding kininogen gene expression during inflammation is crucial for inflammatory disease research.
Purpose of the Study:
- To investigate the differential regulation of rat prekininogen messenger RNA (mRNA) levels in response to acute inflammation.
- To determine the specific impact of Escherichia coli lipopolysaccharide (LPS) on various kininogen mRNA forms.
Main Methods:
- Blot-hybridization and S1 nuclease protection analyses were employed.
- Specific cDNA probes were used to differentiate between K-prekininogen and two types of T-prekininogen mRNAs.
- Acute inflammation was induced using Escherichia coli lipopolysaccharide (LPS).
Main Results:
- Low molecular weight (LMW) prekininogen mRNAs, particularly T-prekininogen mRNAs, showed significant induction following LPS administration.
- T-prekininogen mRNA levels increased 10- to 13-fold, constituting a major portion of liver mRNA during inflammation.
- High molecular weight and LMW K-prekininogen mRNAs did not exhibit a similar increase.
Conclusions:
- Rat T-prekininogen mRNA expression is significantly upregulated during acute inflammation.
- Rat K-prekininogen mRNA expression is not significantly affected by acute inflammation.
- These findings demonstrate differential regulation of T- and K-prekininogen gene expression in response to inflammatory stimuli.