Transforming growth factor-␤-activated kinase 1 (TAK1) plays an essential role in the tumor necrosis factor ␣ (TNF␣)-and interleukin-1␤ (IL-1␤)-induced IB kinase (IKK)/nuclear factor-B (NF-B) and c-Jun N-terminal kinase (JNK)/Tumor necrosis factor ␣ (TNF␣) 3 and interleukin-1␤ (IL-1␤) are two potent proinflammatory cytokines that play important roles in the regulation of immunity, inflammation, cell proliferation, differentiation, and apoptosis (1, 2). Cellular responses to TNF␣ and IL-1␤ are mediated by intracellular signaling pathways that control the activation of nuclear factor-B (NF-B) and activator protein 1 (AP-1) (3, 4).Upon binding to its receptor, TNF␣ induces formation of a receptor-associated complex, including the adaptor proteins TRADD, TRAF2, TRAF5, and RIP1, which subsequently leads to Lys 63 -linked polyubiquitination of TRAF2 and RIP1 (5-7). In contrast, IL-1␤ binding to its receptor induces a receptor-associated complex formation, including MyD88, IRAK1, IRAK4, and TRAF6, which is followed by Lys 63 -linked polyubiquitination of TRAF6 and IRAKs (8 -12). The formation of TRAF2-RIP1 and TRAF6-IRAK4 complexes as well as the Lys 63 -linked polyubiquitination of RIP1 and TRAF6 appear to enable the recruitment and activation of transforming growth factor-␤-activated kinase 1 (TAK1) through binding of the TAK1 regulatory subunits TAB2 and TAB3 to the Lys 63 -polyubiquitinated RIP1 and TRAF6. The activated TAK1 then triggers the activation of the IB kinase (IKK), c-Jun N-terminal kinase (JNK), and p38 MAPK (8,(13)(14)(15)(16)(17), which leads to activation of transcription factors NF-B and AP-1 and up-regulation of many genes encoding proinflammatory cytokines, chemokines, adhesion molecules, and proteolytic enzymes (18).The IKK complex consists of three subunits: two catalytic subunits, IKK␣ and IKK␤, and an essential regulatory subunit, IKK␥/NF-B essential modulator (NEMO) (3,19). Genetic studies have implicated that IKK␤ and IKK␥/NEMO are essential for the TNF␣-and IL-1␤-mediated . Phosphorylation of serine 177 and 181 residues in the activation loop is required for IKK␤ activation (23). IKK␥/NEMO has been indicated to bind Lys 63 -linked polyubiquitin chains (7,16,24,25). It is proposed that Lys 63 -polyubiquitin chains act as a scaffold to allow for assembly of a signaling complex that leads to IKK␤ activation. Once activated, IKK␤ phosphorylates IB proteins and leads to IB polyubiquitination with a Lys 48 -linked ubiquitin chain. Polyubiquitination-mediated degradation of IBs allows NF-B to translocate into the nucleus and activate NF-B-dependent gene expression (26).JNKs are members of three related mitogen-activated protein kinases (MAPKs), including the extracellular signal-regulated kinases (ERKs), JNKs, and p38 MAPKs (4, 27). JNKs and p38 MAPKs are involved in transmitting intracellular signals in

Lys63-linked polyubiquitination of TAK1 plays an important role in TNFα-induced NF-κB activation. Using a functional genomic approach, we have identified Ubiquitin Specific Peptidase 4 (USP4) as a deubiquitinase for TAK1. USP4 deubiquitinates TAK1 in vitro and in vivo. TNFα induces association of USP4 with TAK1 to deubiquitinate TAK1 and downregulate TAK1-mediated NF-κB activation. Overexpression of USP4 wild-type, but not deuibiquitinase-deficient C311A mutant, inhibits both TNFα- and TAK1/TAB1 co-overexpression-induced TAK1 polyubiquitination and NF-κB activation. Notably, knockdown of USP4 in HeLa cells enhances TNFα-induced TAK1 polyubiquitination, IKK phosphorylation, IκBα phosphorylation and ubiquitination as well as NF-κB-dependent gene expression. Moreover, USP4 negatively regulates IL-1β-, LPS-and TGFβ-induced NF-κB activation. Together, our results demonstrate that USP4 serves as a critical control to downregulate TNFα-induced NF-κB activation through deubiquitinating TAK1.

Ubiquitination and deubiquitination of receptor-interacting protein 1 (RIP1) play an important role in the positive and negative regulation of the tumor necrosis factor ␣ (TNF␣)-induced nuclear factor B (NF-B) activation. Using a combination of functional genomic and proteomic approaches, we have identified ubiquitin-specific peptidase 21 (USP21) as a deubiquitinase for RIP1. USP21 is constitutively associated with RIP1 and deubiquitinates RIP1 in vitro and in vivo. Notably, knockdown of USP21 in HeLa cells enhances TNF␣-induced RIP1 ubiquitination, IB kinase ␤ (IKK␤), and NF-B phosphorylation, inhibitor of NF-B ␣ (IB␣) phosphorylation and ubiquitination, as well as NF-B-dependent gene expression. Therefore, our results demonstrate that USP21 plays an important role in the down-regulation of TNF␣-induced NF-B activation through deubiquitinating RIP1. Transcription factor nuclear factor B (NF-B)3 plays an important role in controlling the expression of survival factors, cytokines, and proinflammatory molecules in a broad range of cellular responses (1-3). NF-B is sequestered in the cytoplasm by a family of inhibitory proteins called inhibitor of NF-B (IB) proteins in inactivated cells. Many intercellular stimuli are capable of triggering the activation of a signal transduction pathway that leads to the degradation of IB proteins through the 26 S proteasome (4 -6). Degradation of the IB proteins allows NF-B translocation from cytoplasm to the nucleus and activates the expression of the target genes (7).Upon binding of tumor necrosis factor ␣ (TNF␣), TNF receptor 1 (TNFR1) recruits several adaptor proteins, including receptorinteracting protein 1 (RIP1/RIPK1) and TNF receptor-associated factor 2 (TRAF2), to form a complex (8, 9). This TNFR1-associated complex initiates the activation of IB kinase (IKK), which phosphorylates IB protein and activates NF-B (10 -17).Protein ubiquitination is a crucial regulatory mechanism in various cellular processes, including cell cycle progression, the DNA damage response, and immune responses (18 -20). In the TNF␣-induced NF-B signal transduction pathway, the Lys 63 -linked polyubiquitination of RIP1 protein mediated by TRAF2 E3 ligase is essential for TNF␣-induced IKK/NF-B activation, whereas phosphorylation of the IB proteins by activated IKK leads to their Lys 48 -linked polyubiquitination, which labels it for its degradation by the 26 S proteasome (21).Several deubiquitinating enzymes, including CYLD, A20, Cezanne, ubiquitin-specific peptidase 15 (USP15), and USP31, have been suggested to be involved in the down-regulation of TNF␣-induced NF-B activation (22-26). However, it remains unclear how deubiquitination plays a role in the down-regulation of TNF␣-induced NF-B activation.The USPs belong to a subclass of the protein-deubiquitinating enzyme (DUB) superfamily that are categorized into five subclasses based on their ubiquitin-protease domains in the human genome and have been shown to be involved in a broad range of biological activities (27). Even though the USP subclass o...

IκBα serves as a central anchoring molecule in the sequestration of NF-κB transcription factor in the cytoplasm. Ubiquitination-mediated IκBα degradation immediately precedes and is required for NF-κB nuclear translocation and activation. However, the precise mechanism for the deubiquitination of IκBα is still not fully understood. Using a proteomic approach, we have identified Ubiquitin Specific Peptidase 11 (USP11) as an IκBα associated deubiquitinase. Overexpression of USP11 inhibits IκBα ubiquitination. Recombinant USP11 catalyzes deubiquitination of IκBα in vitro. Moreover, knockdown of USP11 expression enhances TNFα-induced IκBα ubiquitination and NF-κB activation. These data demonstrate that USP11 plays an important role in the downregulation of TNFα-mediated NF-κB activation through modulating IκBα stability. In addition, overexpression of a catalytically inactive USP11 mutant partially inhibits TNFα- and IKKβ-induced NF-κB activation, suggesting that USP11 also exerts a non-catalytic function in its negative regulation of TNFα-mediated NF-κB activation. Thus, IκBα ubiquitination and deubiquitination processes function as a Yin-Yang regulatory mechanism on TNFα-induced NF-κB activation.

Children born to ovarian-hyperstimulated women displayed cardiovascular dysfunctions. The underlying mechanisms may involve the effects of supraphysiological estradiol and progesterone levels.

BackgroundThe increasing number of babies conceived by in vitro fertilization and embryo transfer (IVF-ET) shifts concern from pregnancy outcomes to long-time health of offspring. Maternal high estradiol (E2) is a major characteristic of IVF-ET and lasts throughout the first trimester of pregnancy. The fetal thyroid develops during this period and may thus be affected by exposure to the supra-physiological E2. The aim of this study is to investigate whether the high E2 maternal environment in the first trimester increases the risk of thyroid dysfunction in children born following IVF-ET.MethodsA cross-sectional survey design was used to carry out face-to-face interviews with consecutive children attending the hospital. A total of 949 singletons born after fresh embryo transfer (ET) (n = 357), frozen ET (n = 212), and natural conception (NC) (n = 380), aged 3 to 10 years old, were included. All children were thoroughly examined. Meanwhile, another 183 newborns, including 55 fresh ET, 48 frozen ET, and 80 NC were studied. Levels of serum T3, FT3, T4, FT4, and TSH and levels of maternal E2 at different stages of the first trimester were examined.ResultsThe mean serum E2 levels of women undergoing fresh ET during the first trimester of pregnancy were significantly higher than those of the women undergoing frozen ET or following NC. The thyroid hormone profile, especially the levels of T4, FT4, and TSH, were significantly increased in 3- to 10-year-old children conceived by fresh ET compared to NC. The same tendency was confirmed in newborns. However, levels of T4 and TSH in the frozen ET group were nearer to that of the NC group. Furthermore, levels of T4 and FT4 in fresh ET were positively correlated with maternal serum levels of E2 during early pregnancy.ConclusionsThe maternal high E2 environment in the first trimester is correlated with increased risk of thyroid dysfunction. Frozen ET could reduce risks of thyroid damage in children conceived by IVF. Further studies are needed to confirm these findings and to better determine the underlying molecular mechanisms and clinical significance.Trial registrationChicCTR-OCC-14004682 (22-05-2014)

Primary ovarian insufficiency (POI) leads to infertility and premature menopause in young women. The genetic etiology of this disorder remains unknown in most patients. Using whole exome sequencing of a large Chinese POI pedigree, we identified a heterozygous 5 bp deletion inducing a frameshift in BNC1, which is predicted to result in a non-sense-mediated decay or a truncated BNC1 protein. Sanger sequencing identified another BNC1 missense mutation in 4 of 82 idiopathic patients with POI, and the mutation was absent in 332 healthy controls. Transfection of recombinant plasmids with the frameshift mutant and separately with the missense mutant in HEK293T cells led to abnormal nuclear localization. Knockdown of BNC1 was found to reduce BMP15 and p-AKT levels and to inhibit meiosis in oocytes. A female mouse model of the human Bnc1 frameshift mutation exhibited infertility, significantly increased serum follicle-stimulating hormone, decreased ovary size and reduced follicle numbers, consistent with POI. We report haploinsufficiency of BNC1 as an etiology of human autosomal dominant POI.

Objectivesmultiple myeloma is a malignant neoplasm of plasma cells mainly affecting elderly patients. Despite the wealth of information available on therapeutic strategies, the etiology and pathogenesis of myeloma remain unclear. In the current study, a meta-analysis was conducted to assess the possible association between rheumatoid arthritis and myeloma.Methodsa literature search was conducted with PubMed, EMBASE and Web of Science for relevant studies published by December 25, 2013. Additionally, we searched annual meeting abstracts of the American Society of Hematology from 2004 to 2013. Only original studies that investigated the association between rheumatoid arthritis and myeloma were included. In total, 8 case-control and 10 cohort studies were identified for analysis.Resultsthe meta-estimate of the association between rheumatoid arthritis and myeloma was 1.14 (95% CI, 0.97–1.33) overall, with significant heterogeneity among studies. The relationship between myeloma and other autoimmune diseases was additionally examined from available data. Our results showed that myeloma risk is increased 1.31 to 1.65-fold in pernicious anemia and 1.36 to 2.30-fold in ankylosing spondylitis patients.ConclusionRheumatoid arthritis does not appear to alter the risk of myeloma, while between-study heterogeneity analyses suggest caution in the interpretation of results. Pernicious anemia and ankylosing spondylitis may be potential risk factors for myeloma development. Future large-scale epidemiological studies with reliable exposure biomarkers are necessary to establish the possible contribution of autoimmune disorders to multiple myeloma.