ABSTRACT
Inducible nitric oxide synthase (iNOS) is a molecule critical for the development of inflammation-associated disorders. Its induction should be tightly controlled in order to maintain cellular homeostasis. Upon lipopolysaccharide (LPS) stimulation, iNOS, in most settings, is induced by the activation of inhibitor of κB-α (IκB-α)-nuclear factor κB (NF-κB) signaling. Farnesyl thiosalicylic acid (FTS), a synthetic small molecule that is considered to detach Ras from the inner cell membrane, has been shown to exhibit numerous anti-inflammatory functions. However, it remains unclear whether and how it affects iNOS induction in macrophages. The present study addressed this issue in cultured macrophages and endotoxemic mice. Results showed that FTS pretreatment significantly prevented LPS-induced increases in iNOS protein and mRNA expression levels in murine cultured macrophages, which were confirmed in organs in vivo from endotoxemic mice, such as the liver and lung. Mechanistic studies revealed that FTS pretreatment did not affect IκB-α degradation and NF-κB activation in LPS-treated macrophages. The nuclear transport of the active NF-κB was also not affected by FTS. But FTS pretreatment reduced the binding of NF-κB to its DNA elements, and reduced NF-κB bindings to iNOS promoter inside LPS-treated macrophages. Finally, our results showed that FST pretreatment increased mouse survival rate compared to LPS alone treatment. Taken together, these results indicate that FTS attenuates iNOS induction in macrophages likely through inhibition of iNOS mRNA transcription, providing further insight into the molecular mechanism of action of FTS in inflammatory disorder therapy.
Subject(s)
Farnesol/analogs & derivatives , Macrophages/drug effects , Nitric Oxide Synthase Type II/genetics , Salicylates/pharmacology , Animals , Cells, Cultured , Farnesol/pharmacology , Lipopolysaccharides , Liver/drug effects , Liver/metabolism , Lung/drug effects , Lung/metabolism , Macrophages/metabolism , Male , Mice, Inbred C57BL , NF-kappa B/metabolism , Nitric Oxide/metabolism , RNA, Messenger/metabolismABSTRACT
OBJECTIVE: To investigate the myocardial proliferation/regeneration capacities at different time points and at different parts of the heart post acute myocardial infarction (AMI) in rats. METHODS: A total of 64 adult Sprague-Dawley (SD) rats were randomly divided into AMI group (left anterior descending coronary ligation, n = 44) and sham-operated group (n = 20). Rats were sacrificed on day 3, 5, 7, 14 and 60 respectively post operation (n = 5-9 at each time point) and ventricular tissues were harvested. 5-Bromo-2-deoxyUridine (Brdu, 50 mg/kg) was injected intraperitoneally at 12 and 24 hours before sacrifice. Morphological and pathological changes of the myocardium were observed after HE staining. Brdu-positive and c-kit and Brdu double-positive cardiomyocytes were analyzed post immunohistochemistry and immunofluorescence staining. Striated structure of new cells was detected by PTAH staining. Alpha-sarcomeric actin antibody was used to identify new cardiomyocytes. RESULT: Brdu-positive cardiomyocytes at border zone and non-ischemic zone were significantly increased at 5 days post AMI and peaked at 7th day post operation (Border zone, AMI: 1.26% ± 0.15% vs.Sham: 0.22% ± 0.06%, P < 0.01; right ventricle, AMI: 0.75% ± 0.12% vs.Sham: 0.18% ± 0.07%, P < 0.01). There was no significant difference between the two groups on the 60th post-operation day. Brdu-positive cells were 1.7-fold higher in infarct border zone than in the right ventricular area of AMI rats on the 7th post operation day (1.26% ± 0.15%, vs.0.75% ± 0.12%, P < 0.01) and was 1.4-fold higher on the 14th post operation day (0.77% ± 0.09%, vs.0.54% ± 0.11%, P < 0.01). PTAH staining evidenced myocardial striated structure inside the new cells. Immunofluorescent assay showed that parts of Brdu positive cells were myocardial actin positive, and the c-kit and Brdu double-positive myocardial cells were also observed. Most nuclei of tehse new cardiomyocytes were small and round-shaped. CONCLUSIONS: Myocardial proliferation/regeneration increased significantly after AMI in rats, especially around the infarct border zone. The myocardial proliferation/regeneration was time-dependent. Parts of the new cardiomyocytes had some characteristics of cardiac stem cells. This study suggests that myocardial proliferation/regeneration may be activated after acute myocardial injury.
