sirolimus and Pseudomonas-Infections

The immune system protects the host from pathogenic microbes, but tight regulation of the evoked response is requisite to limit bystander damage. The interleukin (IL)-10 family of cytokines, composed of 9 members: IL-10, IL-19, IL-20, IL-22, IL-24, IL-26, and 3 distantly related members, IL-28A, IL-28B, and IL-29, plays a central role in this regulation. IL-10 family cytokines emerged before the adaptive immune response and elicit diverse host defense mechanisms, especially from epithelial cells during an infection. IL-10 family cytokines are also essential for maintenance and integrity of tissue epithelial layers. These cytokines promote innate immune responses from tissue epithelia that limit the damage caused by both viral and bacterial infections. They also facilitate tissue healing after infection/inflammation. In this regard, IL-10 suppresses pro-inflammatory responses, limiting tissue disruption resulting from an inflammatory response. Thus, a central functional theme of IL-10 family cytokines is their role in tissue protection. This review focuses on IL-10, the founding member of this family of cytokines, and integrates recent data on the function and regulation of IL-10 during bacterial infections. Emphasis is placed on the role of IL-10 in Pseudomonas aeruginosa keratitis and the subsequent infectious/inflammatory processes evoked.

Topics: Animals; Anti-Bacterial Agents; Bacterial Infections; Eye Infections, Bacterial; Humans; Interleukin-10; Keratitis; Pseudomonas aeruginosa; Pseudomonas Infections; Sirolimus

N-(3-oxododecanoyl) homoserine lactone (3oc) is a Pseudomonas aeruginosa secreted quorum-sensing signal molecule playing a crucial role in regulating quorum-sensing (QS) dependent biofilm formation and secretion of virulence factors. In addition to regulating quorum sensing, 3oc also plays an immunomodulatory role in the host by triggering regulated cell death in immune cells. The molecular mechanisms of 3oc in modulating macrophage pathologies are still unclear. In this study, we hypothesized the novel 3oc mediated crosstalk between autophagy and apoptosis at the interphase of calcium signaling in human macrophages. The study showed that 3oc induces mitochondrial dysfunction and apoptosis in macrophages through elevating cytosolic Ca

Topics: 4-Butyrolactone; Apoptosis; Autophagy; Beclin-1; Calcium; Calcium Signaling; Chelating Agents; Chloroquine; Egtazic Acid; Homoserine; Humans; Macrophages; Phosphatidylserines; Protein Kinases; Pseudomonas aeruginosa; Pseudomonas Infections; Quorum Sensing; Reactive Oxygen Species; Sirolimus; Virulence Factors

IL-10 is important in the resistance response of BALB/c mice to experimental Pseudomonas aeruginosa corneal infection. However, the cellular mechanisms by which this anti-inflammatory cytokine is regulated remain unknown. Because the mammalian target of rapamycin (mTOR) regulates IL-10 in other disease models, the present study tested its role in bacterial keratitis. After infection, corneas of rapamycin versus control-treated BALB/c mice showed worsened disease, and real-time RT-PCR confirmed that mTOR mRNA levels were significantly decreased. Rapamycin treatment also increased clinical score, polymorphonuclear neutrophil (PMN) infiltration (determined by myeloperoxidase assay), and bacterial load, but it diminished PMN bactericidal activity. Inhibition of mTOR also led to elevated mRNA and protein levels of IL-12p40, matrix metalloproteinase 9, and inducible NO synthase, whereas mRNA and protein levels of IL-10, its regulator/effector STAT-3, and suppressor of cytokine signaling 3 (a proinflammatory cytokine regulator) were decreased. Furthermore, mTOR inhibition reduced levels of proapoptotic caspase-3 and increased levels of B cell lymphoma-2 (antiapoptotic), indicative of delayed apoptosis. mTOR inhibition also altered genes related to TLR signaling, including elevation of TLR4, TLR5, and IL-1R1, with decreases in IL-1R-associated kinase 1 and an inhibitor of NF-κB, NF-κB inhibitor-like 1. Rapamycin treatment also increased levels of IFN-γ and CCAAT/enhancer binding protein, β, a gene that regulates expression of preprotachykinin-A (the precursor of substance P). Collectively, these data, as well as a rescue experiment using rIL-10 together with rapamycin, which decreased PMN in cornea, provide concrete evidence that mTOR regulates IL-10 in P. aeruginosa-induced bacterial keratitis and is critical to balancing pro- and anti-inflammatory events, resulting in better disease outcome.

Topics: Animals; Apoptosis; Bacterial Load; CCAAT-Enhancer-Binding Protein-beta; Cytokines; Female; Gene Expression Regulation; Interleukin-10; Keratitis; Mice; Neutrophil Infiltration; Neutrophils; Nitrites; Peroxidase; Phagocytosis; Pseudomonas aeruginosa; Pseudomonas Infections; RNA, Messenger; Sirolimus; STAT3 Transcription Factor; Toll-Like Receptors; TOR Serine-Threonine Kinases

Hepatotoxicity, including cholestasis, is a rare but significant complication of treatment with calcineurin inhibitors. Timely life-saving therapy with revision of immunosuppression is mandatory. A 43-year-old woman with pulmonary hypertension was found to have severe cholestasis (serum bilirubin up to 35 mg/dL) after a living-donor lobar lung transplantation. Calcineurin-inhibitor cholestasis markedly improved after withdrawal of the calcineurin inhibitor, initiation of sirolimus, and interleukin-2 receptor blockade. Awareness of the diagnostic criteria of this rare posttransplant complication is important to initiate timely therapy.

Topics: Adult; Calcineurin; Calcineurin Inhibitors; Cholestasis; Disease Progression; Fatal Outcome; Female; Graft Rejection; Humans; Hypertension, Pulmonary; Immunosuppressive Agents; Living Donors; Lung Transplantation; Methylprednisolone; Pneumonia, Bacterial; Postoperative Complications; Pseudomonas Infections; Risk Assessment; Sirolimus; Tacrolimus; Transplantation Immunology