Anti-inflammatory effects of chemically modified tetracyclines by the inhibition of nitric oxide and interleukin-12 synthesis in J774 cell line.
We investigated the effects of chemically modified tetracyclines (CMTs) on the production of nitric oxide (NO) and on the synthesis of some cytokines: tumour necrosis factor alpha (TNF-alpha), interleukin(IL)-10 and IL-12 in lipopolysaccharide (LPS)-treated J774 cell line. Furthermore, we studied the ability of these drugs to modify the viability in LPS-stimulated J774 macrophages. CMTs decreased, in a dose-dependent manner, inducible NO synthase (iNOS) activity and, consequently, nitrite formation in J774 cultures. The CMT-induced decrease in NO production is due to the inhibition of enzyme activity rather than to a direct effect on enzyme expression. The absence of the inhibition in mRNA accumulation indicates that the inhibiting activity is mainly post-transcriptional. CMTs were unable to modulate TNF-alpha and IL-10 synthesis and they were not effective in modifying the transcription of relative mRNA in J774 macrophages. On the contrary, IL-12 mRNA expression was significantly increased by CMT-1 and CMT-8 with LPS activation. Since IL-12 protein secretion was inhibited by CMTs, these compounds interfere in the blocking of post-transcriptional events. The studies on cell viability showed that various CMTs induced a dose-dependent decrease in J774 macrophage viability. The cytotoxic activity was present even though NO production was inhibited by CMTs. These compounds appear to be able to activate apoptosis in aNO-independent way. Altogether, these results indicate that CMTs can exert anti-inflammatory effects by inhibiting NO synthesis, and they are able to modify cell viability by exerting a strong apoptotic activity.
D'Agostino
P
P
Department of Immuno-Haematology and Transfusion, University of Palermo, Italy.
Ferlazzo
V
V
Milano
S
S
La Rosa
M
M
Di Bella
G
G
Caruso
R
R
Barbera
C
C
Grimaudo
S
S
Tolomeo
M
M
Feo
S
S
Cillari
E
E
D000165:Acridine Orange; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D016207:Cytokines / Q000096:biosynthesis; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004797:Enzyme-Linked Immunosorbent Assay; D004996:Ethidium; D005456:Fluorescent Dyes; D020287:In Situ Nick-End Labeling; D007202:Indicators and Reagents; D018664:Interleukin-12 / Q000096:biosynthesis*; D051379:Mice; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D052247:Nitric Oxide Synthase Type II; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013754:Tetracyclines / Q000494:pharmacology*
D000894:Anti-Inflammatory Agents, Non-Steroidal; D016207:Cytokines; D004791:Enzyme Inhibitors; D005456:Fluorescent Dyes; D007202:Indicators and Reagents; D012333:RNA, Messenger; D013754:Tetracyclines; D018664:Interleukin-12; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D004996:Ethidium; D000165:Acridine Orange