LPS resistance of SPRET/Ei mice is mediated by Gilz, encoded by the Tsc22d3 gene on the X chromosome.

Natural variation for LPS-induced lethal inflammation in mice is useful for identifying new genes that regulate sepsis, which could form the basis for novel therapies for systemic inflammation in humans. Here we report that LPS resistance of the inbred mouse strain SPRET/Ei, previously reported to depend on the glucocorticoid receptor (GR), maps to the distal region of the X-chromosome. The GR-inducible gene Tsc22d3, encoding the protein Gilz and located in the critical region on the X-chromosome, showed a higher expressed SPRET/Ei allele, regulated in cis. Higher Gilz levels were causally related to reduced inflammation, as shown with knockdown and overexpression studies in macrophages. Transient overexpression of Gilz by hydrodynamic plasmid injection confirmed that Gilz protects mice against endotoxemia Our data strongly suggest that Gilz is responsible for the LPS resistance of SPRET/Ei mice and that it could become a treatment option for sepsis.

UNBS5162, a novel naphthalimide that decreases CXCL chemokine expression in experimental prostate cancers.

Several naphthalimides have been evaluated clinically as potential anticancer agents. UNBS3157, a naphthalimide that belongs to the same class as amonafide, was designed to avoid the specific activating metabolism that induces amonafide's hematotoxicity. The current study shows that UNBS3157 rapidly and irreversibly hydrolyzes to UNBS5162 without generating amonafide. In vivo UNBS5162 after repeat administration significantly increased survival in orthotopic human prostate cancer models. Results obtained by the National Cancer Institute (NCI) using UNBS3157 and UNBS5162 against the NCI 60 cell line panel did not show a correlation with any other compound present in the NCI database, including amonafide, thereby suggesting a unique mechanism of action for these two novel naphthalimides. Affymetrix genome-wide microarray analysis and enzyme-linked immunosorbent assay revealed that in vitro exposure of PC-3 cells to UNBS5162 (1 microM for 5 successive days) dramatically decreased the expression of the proangiogenic CXCL chemokines. Histopathology additionally revealed antiangiogenic properties in vivo for UNBS5162 in the orthotopic PC-3 model. In conclusion, the present study reveals UNBS5162 to be a pan-antagonist of CXCL chemokine expression, with the compound displaying antitumor effects in experimental models of human refractory prostate cancer when administered alone and found to enhance the activity of taxol when coadministered with the taxoid.

The wild-derived inbred mouse strain SPRET/Ei is resistant to LPS and defective in IFN-beta production.

Although activation of Toll-like receptor 4 (TLR4)-positive cells is essential for eliminating Gram-negative bacteria, overactivation of these cells by the TLR4 ligand LPS initiates a systemic inflammatory reaction and shock. Here we demonstrate that SPRET/Ei mice, derived from Mus spretus, exhibit a dominant resistance against LPS-induced lethality. This resistance is mediated by bone marrow-derived cells. Macrophages from these mice exhibit normal signaling and gene expression responses that depend on the myeloid differentiation factor 88 adaptor protein, but they are impaired in IFN-beta production. The defect appears to be specific for IFN-beta, although the SPRET/Ei IFN-beta promoter is normal. In vivo IFN-beta induction by LPS or influenza virus is very low in SPRET/Ei mice, but IFN-beta-treatment restores the sensitivity to LPS, and IFN type 1 receptor-deficient mice are also resistant to LPS. Because of the defective induction of IFN-beta, these mice are completely resistant to Listeria monocytogenes and highly sensitive to Leishmania major infection. Stimulation of SPRET/Ei macrophages leads to rapid down-regulation of IFN type 1 receptor mRNA expression, which is reflected in poor induction of IFN-beta-dependent genes. This finding indicates that the resistance of SPRET/Ei mice to LPS is due to disruption of a positive-feedback loop that amplifies IFN-beta production. In contrast to TLR4-deficient mice, SPRET/Ei mice resist both LPS and sepsis induced with Klebsiella pneumoniae.

HSP70 protects against TNF-induced lethal inflammatory shock.

The heat shock (HS) response is a universal response activated after exposure to various stimuli. The major HS protein (HSP) is the 72 kDa HSP70 with strong homology in different eukaryotic species. We demonstrate that HS treatment of mice leads to a strong induction of HSP70 in several organs and confers significant protection against lethality induced by tumor necrosis factor (TNF). HS prevents high production of interleukin-6 and nitric oxide and reduces severe damage and apoptosis of the enterocytes in the bowel. Mice deficient in the inducible hsp70.1 gene were no longer protected by HS treatment. We show that HS can be applied successfully in an antitumor protocol based on TNF and interferon-gamma, leading to a significant inhibition of lethality but not to a reduction of antitumoral capacity.

Response of TNF-hyporesponsive SPRET/Ei mice in models of inflammatory disorders.

Most inflammatory disorders are becoming more prevalent, especially in Western countries. The pro-inflammatory cytokine tumor necrosis factor-alpha (TNF) plays a prominent role in many of these inflammatory disorders. We have previously shown that SPRET/Ei mice exhibit an extreme and dominant resistance to high doses of TNF. In this report, we investigate the response of heterozygous (C57BL/6xSPRET/Ei)F1 mice in different models of inflammatory diseases. Compared with C57BL/6 mice, (B x S)F1 mice are protected against TNF-induced arthritis and are partially protected against allergic asthma in an ovalbumin-induced model. However, these mice display complete susceptibility to TNF-induced inflammatory bowel disease. These results indicate that the SPRET/Ei genome harbors potent dominant antiinflammatory genes that might be relevant for the treatment of certain chronic inflammatory diseases. It is very well possible that different genes are implicated in the different models.