Rapamycin Augments the NMDA-Mediated TNF Suppression of MRSA-Stimulated RAW264.7 Murine Macrophages
Background. Methicillin-resistant Staphylococcus aureus (MRSA) can stimulate massive cytokine release. Ketamine suppresses tumor necrosis factor (TNF) secretion by MRSA-stimulated RAW264.7 macrophages, and the mechanism likely involves N-methyl-D-aspartic acid (NMDA) receptor antagonism. The downstr...
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| Format: | Article |
| Language: | English |
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Wiley
2012-01-01
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| Series: | International Journal of Inflammation |
| Online Access: | http://dx.doi.org/10.1155/2012/542727 |
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| author | Thomas Spentzas Rebekah K. H. Shappley Fabio Savorgnan Elizabeth Meals B. Keith English |
| author_facet | Thomas Spentzas Rebekah K. H. Shappley Fabio Savorgnan Elizabeth Meals B. Keith English |
| author_sort | Thomas Spentzas |
| collection | DOAJ |
| description | Background. Methicillin-resistant Staphylococcus aureus (MRSA) can stimulate massive cytokine release. Ketamine suppresses tumor necrosis factor (TNF) secretion by MRSA-stimulated RAW264.7 macrophages, and the mechanism likely involves N-methyl-D-aspartic acid (NMDA) receptor antagonism. The downstream effects of NMDA-mediated TNF suppression, specifically the PI3K/Akt and mTOR modulation, have not been described. Methods. RAW264.7 cells were stimulated for 18 hrs with 105 to 107 CFU/mL inocula of either of two prototypical community-acquired- (CA-) MRSA isolates, USA300 strain LAC and USA400 strain MW2. Then we added the NMDA inhibitors ketamine or 2R-amino-5-phosphonopentanoate (AP5), NMDA substrate, LY294002, and rapamycin in various combinations. Results. NMDA inhibition suppressed TNF secretion by almost a third compared to the no-ketamine control. When NMDA substrate was added, the TNF secretion increased by 10%. Addition of LY294002 suppressed TNF production by macrophages by 20%. Rapamycin exhibited a concentration-dependent TNF induction-suppression response: induction at doses of 0.1 and 1 ng/mL and suppression at 10 and 100 ng/mL. Induction of TNF was abolished when LY294002 was added and the suppression became uniform. Ketamine-induced suppression of TNF secretion was intensified 10–15% when rapamycin was added, but not when LY294002 was added. Conclusion. These findings suggest that NMDA-induced TNF suppression can be augmented by concurrent mTOR inhibition. |
| format | Article |
| id | doaj-art-ed3572e6d9ee4df4a441d0895e665ea8 |
| institution | OA Journals |
| issn | 2090-8040 2042-0099 |
| language | English |
| publishDate | 2012-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | International Journal of Inflammation |
| spelling | doaj-art-ed3572e6d9ee4df4a441d0895e665ea82025-08-20T02:22:09ZengWileyInternational Journal of Inflammation2090-80402042-00992012-01-01201210.1155/2012/542727542727Rapamycin Augments the NMDA-Mediated TNF Suppression of MRSA-Stimulated RAW264.7 Murine MacrophagesThomas Spentzas0Rebekah K. H. Shappley1Fabio Savorgnan2Elizabeth Meals3B. Keith English4Division of Pediatric Critical Care, Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN 38103, USADivision of Pediatric Critical Care, Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN 38103, USADivision of Pediatric Critical Care, Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN 38103, USAChildren's Foundation Research Center, Memphis, TN 38103, USAChildren's Foundation Research Center, Memphis, TN 38103, USABackground. Methicillin-resistant Staphylococcus aureus (MRSA) can stimulate massive cytokine release. Ketamine suppresses tumor necrosis factor (TNF) secretion by MRSA-stimulated RAW264.7 macrophages, and the mechanism likely involves N-methyl-D-aspartic acid (NMDA) receptor antagonism. The downstream effects of NMDA-mediated TNF suppression, specifically the PI3K/Akt and mTOR modulation, have not been described. Methods. RAW264.7 cells were stimulated for 18 hrs with 105 to 107 CFU/mL inocula of either of two prototypical community-acquired- (CA-) MRSA isolates, USA300 strain LAC and USA400 strain MW2. Then we added the NMDA inhibitors ketamine or 2R-amino-5-phosphonopentanoate (AP5), NMDA substrate, LY294002, and rapamycin in various combinations. Results. NMDA inhibition suppressed TNF secretion by almost a third compared to the no-ketamine control. When NMDA substrate was added, the TNF secretion increased by 10%. Addition of LY294002 suppressed TNF production by macrophages by 20%. Rapamycin exhibited a concentration-dependent TNF induction-suppression response: induction at doses of 0.1 and 1 ng/mL and suppression at 10 and 100 ng/mL. Induction of TNF was abolished when LY294002 was added and the suppression became uniform. Ketamine-induced suppression of TNF secretion was intensified 10–15% when rapamycin was added, but not when LY294002 was added. Conclusion. These findings suggest that NMDA-induced TNF suppression can be augmented by concurrent mTOR inhibition.http://dx.doi.org/10.1155/2012/542727 |
| spellingShingle | Thomas Spentzas Rebekah K. H. Shappley Fabio Savorgnan Elizabeth Meals B. Keith English Rapamycin Augments the NMDA-Mediated TNF Suppression of MRSA-Stimulated RAW264.7 Murine Macrophages International Journal of Inflammation |
| title | Rapamycin Augments the NMDA-Mediated TNF Suppression of MRSA-Stimulated RAW264.7 Murine Macrophages |
| title_full | Rapamycin Augments the NMDA-Mediated TNF Suppression of MRSA-Stimulated RAW264.7 Murine Macrophages |
| title_fullStr | Rapamycin Augments the NMDA-Mediated TNF Suppression of MRSA-Stimulated RAW264.7 Murine Macrophages |
| title_full_unstemmed | Rapamycin Augments the NMDA-Mediated TNF Suppression of MRSA-Stimulated RAW264.7 Murine Macrophages |
| title_short | Rapamycin Augments the NMDA-Mediated TNF Suppression of MRSA-Stimulated RAW264.7 Murine Macrophages |
| title_sort | rapamycin augments the nmda mediated tnf suppression of mrsa stimulated raw264 7 murine macrophages |
| url | http://dx.doi.org/10.1155/2012/542727 |
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