Journal Article

IVIS, RediJect Inflammation Probe, chemiluminescence, XenoLight, Adaptor Proteins, Signal Transducing/metabolism; Animals; Cell Differentiation; Concanavalin A/toxicity; Dengue Hemorrhagic Fever/etiology; Disease Models, Animal; Disease Progression; Female; Humans; Immunity, Innate; Intracellular Signaling Peptides and Proteins/metabolism; Lectins, C-Type/deficiency/genetics/*immunology; Liver/metabolism/pathology; Mice; Mice, Inbred C57BL; Mice, Knockout; Models, Immunological; Myeloid Cells/*immunology/pathology; Nitric Oxide/biosynthesis; Nitric Oxide Synthase Type II/metabolism; Nitric Oxide Synthase Type III/metabolism; Phosphatidylinositol 3-Kinases/metabolism; Protein-Tyrosine Kinases/metabolism; Proto-Oncogene Proteins c-akt/metabolism; Receptors, Cell Surface/deficiency/genetics/*immunology; Receptors, Immunologic/metabolism; Shock/*etiology/*immunology/metabolism/pathology; Signal Transduction; Systemic Inflammatory Response; Syndrome/etiology/immunology/metabolism/pathology; Tumor Necrosis Factor-alpha/biosynthesis

Systemic inflammatory response syndrome (SIRS) is a potentially lethal condition, as it can progress to shock, multi-organ failure, and death. It can be triggered by infection, tissue damage, or hemorrhage. The role of tissue injury in the progression from SIRS to shock is incompletely understood. Here, we show that treatment of mice with concanavalin A (ConA) to induce liver injury triggered a G-CSF-dependent hepatic infiltration of CD11b+Gr-1+Ly6G+Ly6C+ immature myeloid cells that expressed the orphan receptor myeloid DAP12-associated lectin-1 (MDL-1; also known as CLEC5A). Activation of MDL-1 using dengue virus or an agonist MDL-1-specific antibody in the ConA-treated mice resulted in shock. The MDL-1+ cells were pathogenic, and in vivo depletion of MDL-1+ cells provided protection. Triggering MDL-1 on these cells induced production of NO and TNF-alpha, which were found to be elevated in the serum of treated mice and required for MDL-1-induced shock. Surprisingly, MDL-1-induced NO and TNF-alpha production required eNOS but not iNOS. Activation of DAP12, DAP10, Syk, PI3K, and Akt was critical for MDL-1-induced shock. In addition, Akt physically interacted with and activated eNOS. Therefore, triggering of MDL-1 on immature myeloid cells and production of NO and TNF-alpha may play a critical role in the pathogenesis of shock. Targeting the MDL-1/Syk/PI3K/Akt/eNOS pathway represents a potential new therapeutic strategy to prevent the progression of SIRS to shock.

Journal Article

MDA-MB-231-D3H2Ln, IVIS, Bioluminescence

Cellular senescence acts as a barrier to cancer progression, and microRNAs (miRNAs) are thought to be potential senescence regulators. However, whether senescence-associated miRNAs (SA-miRNAs) contribute to tumor suppression remains unknown. Here, we report that miR-22, a novel SA-miRNA, has an impact on tumorigenesis. miR-22 is up-regulated in human senescent fibroblasts and epithelial cells but down-regulated in various cancer cell lines. miR-22 overexpression induces growth suppression and acquisition of a senescent phenotype in human normal and cancer cells. miR-22 knockdown in presenescent fibroblasts decreased cell size, and cells became more compact. miR-22-induced senescence also decreases cell motility and inhibits cell invasion in vitro. Synthetic miR-22 delivery suppresses tumor growth and metastasis in vivo by inducing cellular senescence in a mouse model of breast carcinoma. We confirmed that CDK6, SIRT1, and Sp1, genes involved in the senescence program, are direct targets of miR-22. Our study provides the first evidence that miR-22 restores the cellular senescence program in cancer cells and acts as a tumor suppressor.

Journal Article

OsteoSense, Animals; Biopsy; Bone Remodeling; Bone and Bones/metabolism/pathology; Calcification, Physiologic; Cardiovascular Abnormalities/blood/complications/pathology/physiopathology; *Disease Progression; Female; Gene Expression Profiling; Gene Expression Regulation; Glycoproteins/metabolism; Humans; Kidney Failure, Chronic/blood/complications/pathology/physiopathology; Male; Mice; Mice, Inbred C57BL; Middle Aged; Mutation/genetics; Osteoclasts/metabolism/pathology; Osteocytes/*metabolism/*pathology; Protein-Serine-Threonine Kinases/genetics; Renal Osteodystrophy/blood/*metabolism/*pathology/physiopathology; Vascular Calcification; *Wnt Signaling Pathway/genetics

Chronic kidney disease-mineral bone disorder (CKD-MBD) is defined by abnormalities in mineral and hormone metabolism, bone histomorphometric changes, and/or the presence of soft-tissue calcification. Emerging evidence suggests that features of CKD-MBD may occur early in disease progression and are associated with changes in osteocyte function. To identify early changes in bone, we utilized the jck mouse, a genetic model of polycystic kidney disease that exhibits progressive renal disease. At 6 weeks of age, jck mice have normal renal function and no evidence of bone disease but exhibit continual decline in renal function and death by 20 weeks of age, when approximately 40% to 60% of them have vascular calcification. Temporal changes in serum parameters were identified in jck relative to wild-type mice from 6 through 18 weeks of age and were subsequently shown to largely mirror serum changes commonly associated with clinical CKD-MBD. Bone histomorphometry revealed progressive changes associated with increased osteoclast activity and elevated bone formation relative to wild-type mice. To capture the early molecular and cellular events in the progression of CKD-MBD we examined cell-specific pathways associated with bone remodeling at the protein and/or gene expression level. Importantly, a steady increase in the number of cells expressing phosphor-Ser33/37-beta-catenin was observed both in mouse and human bones. Overall repression of Wnt/beta-catenin signaling within osteocytes occurred in conjunction with increased expression of Wnt antagonists (SOST and sFRP4) and genes associated with osteoclast activity, including receptor activator of NF-kappaB ligand (RANKL). The resulting increase in the RANKL/osteoprotegerin (OPG) ratio correlated with increased osteoclast activity. In late-stage disease, an apparent repression of genes associated with osteoblast function was observed. These data confirm that jck mice develop progressive biochemical changes in CKD-MBD and suggest that repression of the Wnt/beta-catenin pathway is involved in the pathogenesis of renal osteodystrophy.

Journal Article

IntegriSense, Animals; Antigens, CD31/metabolism; Capillaries/metabolism; Diagnostic Imaging/*methods; Femoral Artery/surgery; Fluorescent Dyes/*diagnostic use/metabolism; Hindlimb/*blood supply/metabolism/pathology; Integrin alphaV/metabolism; Integrin alphaVbeta3/antagonists & inhibitors/metabolism; Ischemia/*pathology; Ligation; Male; Mice; Mice, Inbred Strains; Microscopy, Fluorescence; *Neovascularization, Physiologic; Plant Lectins/metabolism; Sensitivity and Specificity

Optical agents targeting alpha(v)beta(3) are potential tools to image the angiogenic response to limb ischemia. The left (L) femoral artery was ligated in 17 mice and sham surgery performed on the contralateral right (R) hindlimb. Seven days later, IntegriSense (2 nmol) was injected into 11 mice and 6 were probe controls. Six hours later, mice underwent optical imaging. Ratios of photon flux in the L/R limbs were calculated. Tissue was stained for alpha(v) , CD31, and lectin. The signal was increased in the ischemic limbs compared to contralateral legs and ratio of photon flux in L/R limb averaged 2.37. Control probe showed no hindlimb signal. IntegriSense colocalized with CD31 by dual fluorescent staining. Ratios for L/R hindlimbs correlated with quantitative lectin staining (r = 0.88, p = 0.003). Optical imaging can identify and quantify angiogenic response to hindlimb ischemia.

Journal Article

Bioware; IVIS, Xenogen; Xen29

Infection is the main cause of biomaterials-related failure. A simple technique to test in-vivo new antimicrobial and/or nonadhesive implant coatings is unavailable. Current in vitro methods for studying bacterial adhesion and growth on biomaterial surfaces lack the influence of the host immune system. Most in vivo methods to study biomaterials-related infections routinely involve implant-removal, preventing comprehensive longitudinal monitoring. In vivo imaging circumvents these drawbacks and is based on the use of noninvasive optical imaging of bioluminescent bacteria. Staphylococcus aureus Xen29 is genetically modified to be stably bioluminescent, by the introduction of a modified full lux operon onto its chromosome. Surgical meshes with adhering S. aureus Xen29 were implanted in mice and bacterial growth and spread into the surrounding tissue was monitored longitudinally from bioluminescence with a highly sensitive CCD camera. Distinct spatiotemporal bioluminescence patterns, extending beyond the mesh area into surrounding tissues were observed. After 10 days, the number of living organisms isolated from explanted meshes was found to correlate with bioluminescence prior to sacrifice of the animals. Therefore, it is concluded that in vivo imaging using bioluminescent bacteria is ideally suited to study antimicrobial coatings taking into account the host immune system. In addition, longitudinal monitoring of infection in one animal will significantly reduce the number of experiments and animals.