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Linkage between blood coagulation and inflammation: stimulation of neutrophil tissue kallikrein by thrombin
W M Cohen1, H F Wu, G L Featherstone
1Department of Periodontics, School of Dentistry, University of North Carolina, Chapel Hill 27599-7450.
Abstract:
There has been major interest in the potential interaction between blood coagulation and inflammation. Most of the effort has focused on cellular interactions involving platelets and polymorphonuclear leukocytes (PMNS). The recent discovery of tissue kallikrein(TK) activity in PMNs prompted the study of the possible role of thrombin(IIa) in this process. Human PMNs were isolated by density gradient centrifugation. Human IIa was compared with fMLP with respect to chemotaxis and enzyme release. Results from the challenges by IIa and fMLP were compared to a NaCl control using Student's paired t-test. IIa was a potent chemotactic agent for PMNs (p less than or equal to 0.0121) and stimulated the release of TK (p less than or equal to 0.0001) as determined by hydrolysis of S-2266. FMLP significantly stimulated PMN chemotaxis (p less than or equal to 0.0028) but had no effect on TK release. Release of TK was confirmed by Western Blot analysis and 35S-methionine incorporation into a 35 KD protein after IIa challenge. These results demonstrate that IIa is chemotactic for PMNs and can cause release of tissue kallikrein demonstrating a direct role for blood coagulation in the regulation of the inflammatory response.
Insights
Thrombin (IIa) acts as a potent chemotactic agent for polymorphonuclear leukocytes (PMNs), stimulating their migration and the release of tissue kallikrein (TK). This highlights a direct role for blood coagulation in regulating inflammatory responses.
Area of Science:
- Biochemistry
- Immunology
- Hematology
Background:
- Growing interest in the interplay between blood coagulation and inflammation.
- Previous research focused on platelet and polymorphonuclear leukocyte (PMN) interactions.
- Recent discovery of tissue kallikrein (TK) activity in PMNs.
Purpose of the Study:
- To investigate the role of thrombin (IIa) in PMN activation and tissue kallikrein (TK) release.
- To compare the effects of thrombin (IIa) with fMLP on PMN chemotaxis and enzyme release.
Main Methods:
- Isolation of human PMNs using density gradient centrifugation.
- Challenging PMNs with thrombin (IIa) and fMLP, with NaCl as a control.
- Assessing chemotaxis and TK release via S-2266 hydrolysis, Western Blot, and 35S-methionine incorporation.
Main Results:
- Thrombin (IIa) demonstrated potent chemotactic activity for PMNs (p ≤ 0.0121).
- Thrombin (IIa) significantly stimulated TK release from PMNs (p ≤ 0.0001).
- fMLP stimulated PMN chemotaxis but did not affect TK release.
Conclusions:
- Thrombin (IIa) is a direct chemoattractant for PMNs.
- Thrombin (IIa) induces the release of tissue kallikrein (TK) from PMNs.
- These findings establish a direct link between blood coagulation and inflammatory regulation.