Interferon regulatory factor 3 deficiency leads to interleukin-17-mediated liver ischemia-reperfusion injury.

UNLABELLED: Interferon regulatory factor 3 (IRF3) is an important transcription factor in Toll-like receptor 4 (TLR4) signaling, a pathway that is known to play a critical role in liver ischemia-reperfusion injury. In order to decipher the involvement of IRF3 in this setting, we first compared the intensity of hepatic lesions in IRF3-deficient versus wildtype mice. We found increased levels of blood transaminases, enhanced liver necrosis, and more pronounced neutrophil infiltrates in IRF3-deficient mice. Neutrophil depletion by administration of anti-Ly6G monoclonal antibody indicated that neutrophils play a dominant role in the development of severe liver necrosis in IRF3-deficient mice. Quantification of cytokine genes expression revealed increased liver expression of interleukin (IL)-12/IL-23p40, IL-23p19 messenger RNA (mRNA), and IL-17A mRNA in IRF3-deficient versus wildtype (WT) mice, whereas IL-27p28 mRNA expression was diminished in the absence of IRF3. The increased IL-17 production in IRF3-deficient mice was functionally relevant, as IL-17 neutralization prevented the enhanced hepatocellular damages and liver inflammation in these animals. Evidence for enhanced production of IL-23 and decreased accumulation of IL-27 cytokine in M1 type macrophage from IRF3-deficient mice was also observed after treatment with lipopolysaccharide, a setting in which liver gamma-delta T cells and invariant natural killer T cells were found to be involved in IL-17A hyperproduction. CONCLUSION: IRF3-dependent events downstream of TLR4 control the IL-23/IL-17 axis in the liver and this regulatory role of IRF3 is relevant to liver ischemia-reperfusion injury.

Expression of galectin-3 in primary and metastatic melanoma: immunohistochemical studies on human lesions and nude mice xenograft tumors.

Galectins are a large family of proteins which bind galactoside-containing glycans. Their role in cancer seems to be important since members of the family may mediate cell adhesion and modulate cell growth. Galectin-3 (Gal-3) is expressed in the nucleus, in the cytoplasm and on the cell surface, and can also be secreted into the extracellular matrix. A series of experimental and clinical data have been reported which indicate that Gal-3 may play a putative role in carcinogenesis, cancer progression and the process of metastasis. To study the possible correlation between Gal-3 expression and malignant potential in primary melanoma lesions, we conducted an immunohistochemical study with monoclonal anti-Gal-3 antibody in a series of primary and metastatic melanoma lesions as well as benign skin pigmented lesions. We also developed a xenograft melanoma model in nude mice with two melanoma cell lines (ATCC G-361 and ATCC HT-144) and assessed staining with the Gal-3 antibody in the xenografts and the metastases. The expression of anti-Gal-3 staining was determined semiquantitatively. The expression of Gal-3 was higher in thin primary melanoma lesions than in benign pigmented skin lesions or metastases and seemed to correlate inversely with the aggressiveness as estimated by the Breslow index which is recognized as the main prognostic factor in melanoma. We propose Gal-3 expression in melanoma as a diagnostic and/or a prognostic parameter and suggest that further studies of such a role for Gal-3 are warranted.