Effect of cholecystokinin octapeptide on diacylglycerol-PKC signaling pathway in rat pulmonary interstitial macrophages stimulated by lipopolysaccharide.
OBJECTIVE
To investigate the effect of cholecystokinin octapeptide (CCK-8) on the diacylglycerol-protein kinase C (DAG-PKC) signaling pathway in rat pulmonary interstitial macrophages (PIM) stimulated by lipopolysaccaride (LPS).


METHODS
The PIM from rat lung tissues were isolated using the collagenase digestion method combined with alveolar lavage and pulmonary vessel perfusion. DAG content and PKC activity were measured by radioenzymatic assay. The translocation of PKCzeta was determined by semi-quantitative immunoblot analysis.


RESULTS
CCK-8, at high concentrations (1 x 10(-6) - 1 x 10(-5) mol/L), decreased DAG content and inhibited PKC activity and PKCzeta translocation compared with that in rat resting PIM of a control group (P< 0.01). LPS increased DAG content, and promoted PKC activity and PKCzeta translocation (P< 0.01). CCK-8 decreased LPS-induced DAG content and inhibited LPS-induced PKC activity and PKCzeta translocation significantly at 1 x 10(-8) - 1 x 10(-5) mol/L (P< 0.01). This inhibitory effect of CCK-8 could be abrogated partly by proglumide (non-selective CCK receptor antagonist), CR-1409 (selective CCK-A receptor antagonist), and CR-2945 (selective CCK-B receptor antagonist) in a concentration-dependent manner (P< 0.01).


CONCLUSIONS
CCK-8 was a negative modulator of the DAG-PKC signaling pathway in rat resting PIM, which is very important for maintaining body homeostasis. It significantly inhibited LPS-induced DAG content, PKC activity and PKCzeta translocation in a concentration-dependent manner. The CCK receptor, especially the CCK-A receptor, might play a major role in this process.
Xu
Shun-Jiang
SJ
Department of Pathophysiology, Hebei Medical University, Shijiazhuang 050017, China.
Gao
Wei-Juan
WJ
Cong
Bin
B
Ma
Chun-Ling
CL
Li
Shu-Jin
SJ
Ling
Yi-Ling
YL
Gu
Zhen-Yong
ZY
Yao
Yu-Xia
YX
D000818:Animals; D001569:Benzodiazepines / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004075:Diglycerides / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005260:Female; D007527:Isoenzymes / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D016676:Macrophages, Alveolar / Q000166:cytology / Q000378:metabolism*; D011377:Proglumide / Q000031:analogs & derivatives / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D011949:Receptors, Cholecystokinin / Q000037:antagonists & inhibitors; D015398:Signal Transduction; D012844:Sincalide / Q000494:pharmacology*; D000099221:Protein Kinase C zeta
D001569:Benzodiazepines; D004075:Diglycerides; D007527:Isoenzymes; D008070:Lipopolysaccharides; D011377:Proglumide; D011493:Protein Kinase C; D011949:Receptors, Cholecystokinin; D012844:Sincalide; D000099221:Protein Kinase C zeta; C011439:1,2-diacylglycerol; C116183:CR 2945; C048181:lorglumide