Nuclear factor B (NF-B) plays a pivotal role in inflammation, immunity, stress responses, and protection from apoptosis. Canonical activation of NF-B is dependent on the phosphorylation of the inhibitory subunit IB␣ that is mediated by a multimeric, high molecular weight complex, called IB kinase (IKK) complex. This is composed of two catalytic subunits, IKK␣ and IKK␤, and a regulatory subunit, NEMO/IKK␥. The latter protein is essential for the activation of IKKs and NF-B, but its mechanism of action is not well understood. Here we identified ABIN-1 (A20 binding inhibitor of NF-B) as a NEMO/IKK␥-interacting protein. ABIN-1 has been previously identified as an A20-binding protein and it has been proposed to mediate the NF-B inhibiting effects of A20. We find that both ABIN-1 and A20 inhibit NF-B at the level of the IKK complex and that A20 inhibits activation of NF-B by de-ubiquitination of NEMO/IKK␥. Importantly, small interfering RNA targeting ABIN-1 abrogates A20-dependent de-ubiquitination of NEMO/ IKK␥ and RNA interference of A20 impairs the ability of ABIN-1 to inhibit NF-B activation. Altogether our data indicate that ABIN-1 physically links A20 to NEMO/IKK␥ and facilitates A20-mediated de-ubiquitination of NEMO/IKK␥, thus resulting in inhibition of NF-B.NF-B is a ubiquitously expressed family of transcription factors that controls the expression of numerous genes involved in immune and inflammatory responses (1). NF-B also plays an important role during cellular stress responses, due to its anti-apoptotic and proliferationpromoting functions (2). Aberrant activation of NF-B is a major hallmark of several inflammatory diseases such as arthritis (3, 4), and a variety of human cancers (5, 6). In resting cells, NF-B is sequestered in the cytoplasm in an inactive form by members of the inhibitory family of IB proteins (1). Various stimuli including pathogens, pathogen-related factors, and cytokines lead to phosphorylation of the inhibitory subunit IB␣ on specific serine residues (Ser 32 and Ser 36 ) (7) catalyzed by two IB kinases (IKKs), [3][4][5][6][7][8][9][10][11][12]. This step marks the IB protein for ubiquitination and subsequent degradation through a proteasome-dependent pathway (1). The active NF-B is then free for translocation to the nucleus, where it binds the B sequences present in the promoters of responsive genes. IKK␣ and IKK␤ reside in a larger kinase complex (700 -900 kDa), called the IB kinase complex (IKK complex), that also contains the essential regulatory subunit NEMO (also known as IKK␥) (13,14). Genetic studies suggest that NEMO/IKK␥ is absolutely required for the activation of IKKs and NF-B in response to different stimuli (13,15). NEMO/IKK␥ contains several coiled-coil domains, a leucine zipper, and a C-terminal zinc finger domain. These motifs are required for the correct assembly of the IKK complex (13) and recruitment of upstream signaling mediators (16). Numerous proteins have been demonstrated to interact with NEMO/IKK␥, as the kinase RIP and the inhibitor of NF-B A20 (17), the ...

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The endoplasmic reticulum represents the quality control site of the cell for folding and assembly of cargo proteins. A variety of conditions can alter the ability of the endoplasmic reticulum (ER) to properly fold proteins, thus resulting in ER stress. Cells respond to ER stress by activating different signal transduction pathways leading to increased transcription of chaperone genes, decreased protein synthesis, and eventually to apoptosis. In the present paper we analyzed the role that the adaptor protein tumor necrosis factorreceptor associated factor 2 (TRAF2) plays in regulating cellular responses to apoptotic stimuli from the endoplasmic reticulum. Mouse embryonic fibroblasts derived from TRAF2؊/؊ mice were more susceptible to apoptosis induced by ER stress than the wild type counterpart. This increased susceptibility to ER stress-induced apoptosis was because of an increased accumulation of reactive oxygen species following ER stress, and was abolished by the use of antioxidant. In addition, we demonstrated that the NF-B pathway protects cells from ER stress-induced apoptosis, controlling ROS accumulation. Our results underscore the involvement of TRAF2 in regulating ER stress responses and the role of NF-B in protecting cells from ER stress-induced apoptosis.

Our results show that NF-kappaB contributes to anaplastic thyroid cancer up-regulating the expression of miR-146a.

The aim of this work was to compare the effects on human amniotic membrane of freeze-drying and c-irradiation at doses of 10, 20 and 30 kGy, with freezing. For this purpose, nine cytokines (interleukin 10, platelet-derived growth factor-AA, plateletderived growth factor-BB, basic fibroblast growth factor, epidermal growth factor, transforming growth factor beta 1, and tissue inhibitors of metalloproteinase-1, -2, and -4) were titrated in 5 different preparations for each of 3 amniotic membranes included in the study. In addition, the extracellular matrix structure of each sample was assessed by transmission electron microscopy. While freeze-drying did not seem to affect the biological structure or cytokine content of the different amniotic membrane samples, c-irradiation led to a significant decrease in the tissue inhibitors of metalloproteinase-4, basic fibroblast growth factor and epidermal growth factor, and induced structural damage to the epithelium, basement membrane and lamina densa. The higher the irradiation dose the more severe the damage to the amniotic membrane structure. In conclusion, the Authors recommend processing amniotic membrane under sterile conditions to guarantee safety at every step rather than final sterilization with c-irradiation, thereby avoiding alteration to the biological characteristics of the amniotic membrane.

a b s t r a c tDiatoms are an important class of unicellular algae that produce bioactive secondary metabolites with cytotoxic activity collectively termed oxylipins, including polyunsaturated aldehydes (PUAs), hydroxyacids (HEPEs), oxo-acids and epoxyalcohols. Previous results showed that at higher concentrations, the PUA decadienal induced apoptosis on copepods and sea urchin embryos via caspase-3 activation; at lower concentrations decadienal affected the expression levels of the caspase-8 gene in embryos of the sea urchin Paracentrotus lividus. In the present work, we studied the effects of other common oxylipins produced by diatoms: two PUAs (heptadienal and octadienal) and four hydroxyacids (5-, 9-11-and 15-HEPE) on P. lividus cell death and caspase activities. Our results showed that (i) at higher concentrations PUAs and HEPEs induced apoptosis in sea urchin embryos, detected by microscopic observation and through the activation of caspase-3/7 and caspase-8 measured by luminescent assays; (ii) at low concentrations, PUAs and HEPEs affected the expression levels of caspase-8 and caspase-3/7 (isolated for the first time here in P. lividus) genes, detected by Real Time qPCR. These findings have interesting implications from the ecological point of view, given the importance of diatom blooms in nutrient-rich aquatic environments.

Our results indicate NGAL as a novel target of nuclear factor-κB prometastatic activity in thyroid cancer through enhancement of MMP-9 enzymatic activity.

Nuclear factor jB (NF-jB) plays a pivotal role in numerous cellular processes, including stress response, inflammation, and protection from apoptosis. Therefore, the activity of NF-jB needs to be tightly regulated. We have previously identified a novel gene, named CIKS (connection to IjB-kinase and SAPK), able to bind the regulatory sub-unit NEMO/IKKc and to activate NFjB. Here, we demonstrate that CIKS forms homo-oligomers, interacts with NEMO/IKKc, and is recruited to the IKK-complex upon cell stimulation. In addition, we identified the regions of CIKS responsible for these functions. We found that the ability of CIKS to oligomerize, and to be recruited to the IKK-complex is not sufficient to activate the NF-jB. In fact, a deletion mutant of CIKS able to oligomerize, to interact with NEMO/IKKc, and to be recruited to the IKK-complex does not activate NF-jB, suggesting that CIKS needs a second level of regulation to efficiently activate NF-jB.