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Journal Article

Animals; Anti-Bacterial Agents; Bioware; Chromosome Mapping; Eye Diseases; Fatty Acids, Monounsaturated; Likelihood Functions; Lod Score; Mice; Mice, Inbred C57BL; Oleic Acid; Receptors, Immunologic; Sequence Analysis, DNA; Skin; Staphylococcal Skin Infections; Stearoyl-CoA Desaturase; Streptococcus pyogenes; Time Factors; Toll-Like Receptor 2; Xen8.1, Xen20, Xen14

flake (flk), an N-ethyl-N-nitrosourea-induced recessive germ line mutation of C57BL/6 mice, impairs the clearance of skin infections by Streptococcus pyogenes and Staphylococcus aureus, gram-positive pathogens that elicit innate immune responses by activating Toll-like receptor 2 (TLR2). Positional cloning and sequencing revealed that flk is a novel allele of the stearoyl coenzyme A desaturase 1 gene (Scd1). flake homozygotes show reduced sebum production and are unable to synthesize the monounsaturated fatty acids (MUFA) palmitoleate (C(16:1)) and oleate (C(18:1)), both of which are bactericidal against gram-positive (but not gram-negative) organisms in vitro. However, intradermal MUFA administration to S. aureus-infected mice partially rescues the flake phenotype, which indicates that an additional component of the sebum may be required to improve bacterial clearance. In normal mice, transcription of Scd1-a gene with numerous NF-kappaB elements in its promoter--is strongly and specifically induced by TLR2 signaling. Similarly, the SCD1 gene is induced by TLR2 signaling in a human sebocyte cell line. These observations reveal the existence of a regulated, lipid-based antimicrobial effector pathway in mammals and suggest new approaches to the treatment or prevention of infections with gram-positive bacteria.

Journal Article

OsteoSense, Animals; Axis/chemistry/*metabolism/*pathology; *Calcification, Physiologic/genetics; Inflammation/genetics/metabolism/prevention & control; Mice; Mice, Transgenic; Molecular Imaging/*methods; Spondylitis, Ankylosing/diagnosis/*genetics/*metabolism; Time Factors

INTRODUCTION: The diagnosis of ankylosing spondylitis is made from a combination of clinical features and the presence of radiographic evidence that may be detected only after many years of inflammatory back pain. It is not uncommon to have a diagnosis confirmed 5 to 10 years after the initial onset of symptoms. Development of a more-sensitive molecular imaging technology to detect structural changes in the joints would lead to earlier diagnosis and quantitative tracking of ankylosis progression. Progressive ankylosis (ank/ank) mice have a loss of function in the Ank gene, which codes for a regulator of PPi transport. In this study, we used these ank/ank mutant mice to assess a noninvasive, quantitative measure of joint ankylosis with near-infrared (NIR) molecular imaging in vivo. METHODS: Three age groups (8, 12, and 18 weeks) of ank/ank (15 mice) and wild-type littermates (12 +/+ mice) were assessed histologically and radiographically. Before imaging, OsteoSense 750 (bisphosphonate pamidronate) was injected i.v. Whole-body images were analyzed by using the multispectral Maestro imaging system. RESULTS: OsteoSense 750 signals in the paw joints were higher in ank/ank mice in all three age groups compared with controls. In the spine, significantly higher OsteoSense 750 signals were detected early, in 8-week-old ank/ank mice compared with controls, although minimal radiographic differences were noted at this time point. The molecular imaging changes in the ank/ank spine (8 weeks) were supported by histologic changes, including calcium apatite crystals at the edge of the vertebral bodies and new syndesmophyte formation. CONCLUSIONS: Changes in joint pathology of ank/ank mice, as evaluated by histologic and radiographic means, are qualitative, but only semiquantitative. In contrast, molecular imaging provides a quantitative assessment. Ankylosis in ank/ank mice developed simultaneously in distal and axial joints, contrary to the previous notion that it is a centripetal process. NIR imaging might be feasible for early disease diagnosis and for monitoring disease progression in ankylosing spondylitis.

Journal Article

Animals; Antineoplastic Agents, Alkylating; Antineoplastic Combined Chemotherapy Protocols; Benzimidazoles; Bioware; Dacarbazine; DNA Damage; DNA Modification Methylases; DNA Repair; DNA Repair Enzymes; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Humans; MDA-MB-231-D3H2LN cells; Mice; Mice, SCID; Neoplasm Metastasis; Neoplasm Transplantation; Tumor Suppressor Proteins

PURPOSE ABT-888, currently in phase 2 trials, is a potent oral poly(ADP-ribose) polymerase inhibitor that enhances the activity of multiple DNA-damaging agents, including temozolomide (TMZ). We investigated ABT-888+TMZ combination therapy in multiple xenograft models representing various human tumors having different responses to TMZ. EXPERIMENTAL DESIGN ABT-888+TMZ efficacy in xenograft tumors implanted in subcutaneous, orthotopic, and metastatic sites was assessed by tumor burden, expression of poly(ADP-ribose) polymer, and O(6)-methylguanine methyltransferase (MGMT). RESULTS Varying levels of ABT-888+TMZ sensitivity were evident across a broad histologic spectrum of models (55-100% tumor growth inhibition) in B-cell lymphoma, small cell lung carcinoma, non-small cell lung carcinoma, pancreatic, ovarian, breast, and prostate xenografts, including numerous regressions. Combination efficacy in otherwise TMZ nonresponsive tumors suggests that TMZ resistance may be overcome by poly(ADP-ribose) polymerase inhibition. Profound ABT-888+TMZ efficacy was seen in experimental metastases models that acquired resistance to TMZ. Moreover, TMZ resistance was overcome in crossover treatments, indicating that combination therapy may overcome acquired TMZ resistance. Neither tumor MGMT, mismatch repair, nor poly(ADP-ribose) polymer correlated with the degree of sensitivity to ABT-888+TMZ. CONCLUSIONS Robust ABT-888+TMZ efficacy is observed across a spectrum of tumor types, including orthotopic and metastatic implantation. As many TMZ nonresponsive tumors proved sensitive to ABT-888+TMZ, this novel combination may broaden the clinical use of TMZ beyond melanoma and glioma. Although TMZ resistance may be influenced by MGMT, neither MGMT nor other mechanisms of TMZ resistance (mismatch repair) precluded sensitivity to ABT-888+TMZ. Underlying mechanisms of TMZ resistance in these models are not completely understood but likely involve mechanisms independent of MGMT.

Journal Article

Animals; Antineoplastic Agents; Autophagy; B16-F10-luc-G5 cells; Bioware; Cell Survival; Cells, Cultured; Ceramides; Cesium Radioisotopes; CHO Cells; Combined Modality Therapy; Cricetinae; Cricetulus; Endothelium, Vascular; Female; Gamma Rays; Gene Expression Regulation, Enzymologic; Gene Therapy; Humans; Melanoma, Experimental; Mice; Sphingomyelin Phosphodiesterase

Exposure of cells or animals to stress frequently induces acid sphingomyelinase (ASM)-mediated ceramide production that leads to cell death. Consistent with this, overexpression of ASM in subcutaneous B16-F10 mouse melanomas, in combination with irradiation, resulted in tumors that were up to 12-fold smaller than irradiated control melanomas. Similarly, when irradiated melanomas were pretreated with a single, peritumoral injection of recombinant ASM (rhASM), the tumors were up to threefold smaller. The in vivo effect of ASM was likely due to enhanced cell death of the tumor cells themselves, as well as the surrounding microvascular endothelial cells. In vitro, rhASM had little or no effect on the growth of tumor cells, even in combination with irradiation. However, when the culture media was acidified to mimic the acidic microenvironment of solid tumors, rhASM-mediated cell death was markedly enhanced when combined with irradiation. Microscopic analysis suggested that this was associated with an increase in autophagy. rhASM has been produced for the treatment of the lysosomal storage disorder, type B Niemann-Pick disease, and is currently being evaluated in a phase-1 clinical trial. Based on the data presented in this article, we propose that further investigation of this protein and gene as antineoplastic agents also is warranted.

Journal Article

ProSense; in vivo imaging; NOD2; mice; inflammatory arthritis; TCR transgenic; knockout

In addition to its role in innate immunity, nucleotide oligomerization domain 2 (NOD2) has been shown to play a suppressive role in models of colitis. Notably, mutations in NOD2 cause the inherited granulomatous disease of the joints called Blau syndrome, thereby linking NOD2 with joint disease as well. However, the role of NOD2 in joint inflammation has not been clarified. We demonstrate here that NOD2 is functional within the mouse joint and promotes inflammation, as locally or systemically administered muramyl dipeptide (MDP; the NOD2 agonist) resulted in significant joint inflammation that was abolished in NOD2-deficient mice. We then sought to investigate the role of NOD2 in a mouse model of inflammatory arthritis dependent on adaptive immunity using TCR-transgenic mice whose T cells recognized the dominant epitope of proteoglycan (PG). Mice immunized with PG in the presence of MDP developed a more severe inflammatory arthritis and histopathology within the joints. Antigen-specific activation of splenocytes was enhanced by MDP with respect to IFN-gamma production, which would be consistent with the Th1-mediated disease in vivo. Intriguingly, NOD2 deficiency did not alter the PG-induced arthritis, indicating that NOD2 does not play an essential role in this model of joint disease when it is not activated by MDP. In conclusion, we demonstrate that in a model of inflammatory arthritis dependent on T and B cell priming, NOD2 activation potentiates disease. However, the absence of NOD2 does not alter the course of inflammatory arthritis, in contrast to models of intestinal inflammation.