Role of mitogen-activated protein kinases, nuclear factor-kappaB, and interferon regulatory factor 3 in Toll-like receptor 4-mediated activation of HIV long terminal repeat.

Monocytes/macrophages are known to represent a potential reservoir of human immunodeficiency virus type 1 (HIV-1), which ensures continuous replication of the virus in patients on highly active antiretroviral therapy (HAART). Infected macrophages are a highly productive source of HIV-1 during infections with common opportunistic pathogens. Previous studies report that toll like receptors (TLR)s play a role in HIV-1 replication in macrophages. Here, we investigate the three main pathways activated through TLR4 and the interactions with the HIV-1 long terminal repeat (LTR), using human embryonic kidney (HEK) 293 cells expressing TLR4 and transfected with a luciferase reporter under the control of the HIV-1 LTR. Here, we demonstrate, that TLR4-mediated activation of HIV-LTR is largely governed by the nuclear factor-kappaB pathway. Neither of the mitogen-activated protein kinases ERK1/2, JNK, or p38 nor the transcription factor interferon regulatory factor 3 were involved in the direct transactivation of HIV-LTR through stimulation of TLR4.

Half body irradiation of patients with multiple bone metastases: a phase II trial.

AIM OF STUDY: The primary aim of this study was to evaluate the effect of half-body irradiation (HBI) on pain and quality of life in cancer patients with multiple bone metastases. The secondary aim was to evaluate side effects of the treatment. PATIENTS AND METHODS: A total of 44 patients received lower (n = 37), upper (n = 5), or sequential HBI (n = 2). The dose for lower HBI was 8 Gy in one fraction and for upper HBI 7 Gy in one fraction, with reduction of the lung dose to 6 Gy in one fraction by partial shielding. The majority of patients (n = 41) were males with prostate cancers (93%). Outcome and side effects were measured by the EORTC Quality of Life Questionnaire C30 (QLQ-C30), and by the doctors' toxicity scores in the medical record. Pain relief was defined as a reduction of more than 10 points on the QLQ-C30 scale. Evaluations were performed before and 2, 4, 8, 16, and 24 weeks after treatment. RESULTS: Relief of pain was observed in 76% of the patients receiving HBI with 8.8% of the patients experiencing complete pain relief with no residual pain in the treated field. For most patients, the pain relief was lasting throughout the follow-up period. About one third of the patients were able to reduce their intake of analgesics. Grade 1-2 diarrhoea was the most common side effect observed in 49% of the patients two weeks after treatment. Mild pulmonary symptoms (grade 1-2) were observed in four of seven patients receiving upper HBI. No clear effect was observed on the patients' global quality of life. CONCLUSION: Single fraction HBI is safe and effective providing long lasting pain reduction in 76% of patients with multiple bone metastases.

Streptococcus pneumoniae stabilizes tumor necrosis factor alpha mRNA through a pathway dependent on p38 MAPK but independent of Toll-like receptors.

BACKGROUND: Streptococcus pneumoniae is a human pathogenic bacteria and a major cause of severe invasive diseases, including pneumonia, bacteremia, and meningitis. Infections with S. pneumoniae evoke a strong inflammatory response, which plays a major role in the pathogenesis of pneumococcal disease. RESULTS: In this study, we have examined how S. pneumoniae affects expression of the inflammatory cytokine tumor necrosis factor (TNF) alpha, and the molecular mechanisms involved. Secretion of TNF-alpha was strongly induced by S. pneumoniae, which was able to stabilize TNF-alpha mRNA through a mechanism dependent on the viability of the bacteria as well as the adenylate uridylate-rich elements in the 3'untranslated region of TNF-alpha mRNA. The ability of S. pneumoniae to stabilize TNF-alpha mRNA was dependent on the mitogen-activated protein kinase (MAPK) p38 whereas inhibition of Toll-like receptor signaling via MyD88 did not affect S. pneumoniae-induced mRNA stabilization. P38 was activated through a pathway involving the upstream kinase transforming growth factor-activated kinase 1 and MAPK kinase 3. CONCLUSION: Thus, S. pneumoniae stabilizes TNF-alpha mRNA through a pathway dependent on p38 but independent of Toll-like receptors. Production of TNF-alpha may contribute significantly to the inflammatory response raised during pneumococcal infection.

Mechanisms of dexamethasone-mediated inhibition of Toll-like receptor signaling induced by Neisseria meningitidis and Streptococcus pneumoniae.

Excessive inflammation contributes to the pathogenesis of bacterial meningitis, which remains a serious disease despite treatment with antibiotics. Therefore, anti-inflammatory drugs have important therapeutic potential, and clinical trials have revealed that early treatment with dexamethasone significantly reduces mortality and morbidity from bacterial meningitis. Here we investigate the molecular mechanisms behind the inhibitory effect of dexamethasone upon the inflammatory responses evoked by Neisseria meningitidis and Streptococcus pneumoniae, two of the major causes of bacterial meningitis. The inflammatory cytokine response was dependent on Toll-like receptor signaling and was strongly inhibited by dexamethasone. Activation of the NF-kappaB pathway was targeted at several levels, including inhibition of IkappaB phosphorylation and NF-kappaB DNA-binding activity as well as upregulation of IkappaB alpha synthesis. Our data also revealed that the timing of steroid treatment relative to infection was important for achieving strong inhibition, particularly in response to S. pneumoniae. Altogether, we describe important targets of dexamethasone in the inflammatory responses evoked by N. meningitidis and S. pneumoniae, which may contribute to our understanding of the clinical effect and the importance of timing with respect to corticosteroid treatment during bacterial meningitis.