TLR signaling-mediated differential histone modification at IL-10 and IL-12 promoter region leads to functional impairments in tumor-associated macrophages.

Tumor-associated macrophages (TAM) are severely compromised for the induction of proinflammatory mediators following toll-like receptor (TLR) activation. Here, we reported that the defective TLR response in TAM was due to the malfunctioning of the myeloid differentiation primary response gene 88 (MyD88)-dependent signaling cascade in concert with downregulation of tumor necrosis factor receptor-associated factor (TRAF) 6 and interleukin-1 receptor-associated kinase (IRAK) 1. However, the expression of toll-interleukin1 receptor domain-containing adapter-inducing interferon beta (TRIF) and TRAF 3, which act via the TRIF-dependent pathway of TLR signaling, were found to be unaffected in TAM. Although, TRIF-mediated signal inducers, lipopolysaccharide or poly (I:C), induced high level of extracellular signal-regulated kinase (ERK)-1/2 mitogen-activated protein kinase (MAPK) phosphorylation, but they were failed to induce significant p38MAPK phosphorylation in TAM. Consequently, ERK-1/2-dependent histone phosphorylation at the IL-10 promoter elicited enhanced interleukin (IL)-10 production by TAM. Whereas, the lack of transcription favorable histone phosphorylation at the IL-12 promoter was accompanied with a very low amount of IL-12 expression in TAM. Moreover, ERK-1/2 MAPK activation resulted in enhanced IRAK M induction in TAM, a specific inhibitor of MyD88 pathway. Therefore, for the first time, we decipher an unexplored TLR signaling in TAM where ERK-1/2 activation in a MyD88-independent pathway results in transcription favorable histone modification at the IL-10 promoter region to enhance IL-10-mediated immunosuppression. Additionally, by enhancing IRAK M induction, it also polarizes TAM toward a more immunosuppressive form.

Alteration of some cellular function in amikacin resistant Pseudomonas aeruginosa transfected macrophages: a time dependent approach.

OBJECTIVE: To evaluate the free radical generation and antioxidant enzymes status in murine peritoneal macrophage during in vitro amikacin resistant Pseudomonas aeruginosa (ARPA) treatment with different time interval. METHODS: Peritoneal macrophages were treated with 1×10(8) CFU/mL ARPA cell suspension in vitro for different time interval (1, 2, 3, 6, 12, and 24 h) and super oxide anion generation, NO generation, reduced glutathione level and antioxidant enzymes status were analyzed. RESULTS: Super oxide anion generation and NO generation got peak at 12 h, indicating maximal free radical generation through activation of NADPH oxidase in murine peritoneal macrophages during ARPA transfection. Reduced glutathione level and antioxidant enzymes status were decreased significantly (P<0.05) with increasing time of ARPA transfection. All the changes in peritoneal macrophages after 12 h in vitro ARPA transfection had significant difference (P<0.05). CONCLUSIONS: From this study, it may be summarized that in vitro ARPA infection not only generates excess free radical but also affects the antioxidant system and glutathione cycle in murine peritoneal macrophage.

Amelioratory Effect of Nanoconjugated Vancomycin on Spleen during VRSA-Induced Oxidative Stress.

Objective. The aim of the present study was to evaluate the possible antioxidant effects of nanoconjugated vancomycin against VRSA infection on select makers of oxidative damage and antioxidant status in spleen. Methods. A coagulase-positive VRSA strain was used for this study. VRSA infection was developed in Swiss mice by intraperitoneal injection of 5 × 10(6) CFU/mL bacterial solutions. VRSA-infected mice were treated with nanoconjugated vancomycin at its effective dose for 10 days. After decapitation, blood was used for determination of viable bacteria count and spleen was excised from control and experimental groups, homogenized and used for different biochemical estimations. Results. Nitrate level, myeloperoxidase activity, lipid peroxidation, protein oxidation, oxidized glutathione, and DNA fragmentation level were increased significantly (P < 0.05) in spleen of VRSA-infected group as compared to control group, and reduced glutathione level, activity of SOD, CAT, GPx, GR, and GST were decreased significantly (P < 0.05); which were increased or decreased significantly (P < 0.05) near to normal in nanoconjugated vancomycin-treated group. Conclusion. These findings suggest the potential use and beneficial role of nanoconjugated vancomycin against VRSA-infection-induced oxidative stress and DNA damage in spleen.

Alteration of some cellular function in amikacin resistant Pseudomonas aeruginosa transfected macrophages：a time dependent approach

To evaluate the free radical generation and antioxidant enzymes status in murine peritoneal macrophage during in vitro amikacin resistant Pseudomonas aeruginosa (ARPA) treatment with different time interval. Methods: Peritoneal macrophages were treated with 1×108 CFU/mL ARPA cell suspension in vitro for different time interval (1, 2, 3, 6, 12, and 24 h) and super oxide anion generation, NO generation, reduced glutathione level and antioxidant enzymes status were analyzed. Results: Super oxide anion generation and NO generation got peak at 12 h, indicating maximal free radical generation through activation of NADPH oxidase in murine peritoneal macrophages during ARPA transfection. Reduced glutathione level and antioxidant enzymes status were decreased significantly (P<0.05) with increasing time of ARPA transfection. All the changes in peritoneal macrophages after 12 h in vitro ARPA transfection had significant difference (P<0.05). Conclusions: From this study, it may be summarized that in vitro ARPA infection not only generates excess free radical but also affects the antioxidant system and glutathione cycle in murine peritoneal macrophage.