Transforming Growth Factor-β-activated Kinase 1 Research Articles

MiR-32-5p aggravates intestinal epithelial cell injury in pediatric enteritis induced by Helicobacter pylori.

BACKGROUNDPediatric enteritis is one of the infectious diseases in the digestive system that causes a variety of digestive problems, including diarrhea, vomiting, and bellyache in children. Clinically, Helicobacter pylori (H. pylori) infection is one of the common factors to cause pediatric enteritis. It has been demonstrated that aberrant expression of microRNAs (miRNAs) is found in gastrointestinal diseases caused by H. pylori, and we discovered a significant increase of miR-32-5p in H. pylori-related pediatric enteritis. However, the exact role of miR-32-5p in it is still unknown.AIMTo investigate the role of aberrant miR-32-5p in pediatric enteritis induced by H. pylori.METHODSMiR-32-5p expression was detected by quantitative real time-polymerase chain reaction. The biological role of miR-32-5p in H. pylori-treated intestinal epithelial cells was evaluated by Cell Counting Kit-8 assay and flow cytometry. The potential target of miR-32-5p was predicted with TargetScanHuman and verified by luciferase assay. The downstream mechanism of miR-32-5p was explored by using molecular biology methods.RESULTSWe found that miR-32-5p was overexpressed in serum of H. pylori-induced pediatric enteritis. Further investigation revealed that H. pylori infection promoted the death of intestinal epithelial cells, and increased miR-32-5p expression. Moreover, miR-32-5p mimic further facilitated apoptosis and inflammatory cytokine secretion of intestinal epithelial cells. Further exploration revealed that SMAD family member 6 (SMAD6) was the direct target of miR-32-5p, and SMAD6 overexpression partially rescued cell damage induced by H. pylori. The following experiments showed that miR-32-5p/SMAD6 participated in the apoptosis of intestinal epithelial cells induced by transforming growth factor-β-activated kinase 1 (TAK1)-p38 activation under H. pylori infection.CONCLUSIONOur work uncovered the crucial role of aberrant expression of miR-32-5p in H. pylori–related pediatric enteritis, and suggested that the TAK1-p38 pathway is involved in it.

Six-Transmembrane Epithelial Antigen of the Prostate 3 Deficiency in Hepatocytes Protects the Liver Against Ischemia-Reperfusion Injury by Suppressing Transforming Growth Factor-β-Activated Kinase 1.

Background and AimsHepatic ischemia‐reperfusion (I/R) injury remains a major challenge affecting the morbidity and mortality of liver transplantation. Effective strategies to improve liver function after hepatic I/R injury are limited. Six‐transmembrane epithelial antigen of the prostate 3 (Steap3), a key regulator of iron uptake, was reported to be involved in immunity and apoptotic processes in various cell types. However, the role of Steap3 in hepatic I/R‐induced liver damage remains largely unclear.Approach and ResultsIn the present study, we found that Steap3 expression was significantly up‐regulated in liver tissue from mice subjected to hepatic I/R surgery and primary hepatocytes challenged with hypoxia/reoxygenation insult. Subsequently, global Steap3 knockout (Steap3‐KO) mice, hepatocyte‐specific Steap3 transgenic (Steap3‐HTG) mice, and their corresponding controls were subjected to partial hepatic warm I/R injury. Hepatic histology, the inflammatory response, and apoptosis were monitored to assess liver damage. The molecular mechanisms of Steap3 function were explored in vivo and in vitro. The results demonstrated that, compared with control mice, Steap3‐KO mice exhibited alleviated liver damage after hepatic I/R injury, as shown by smaller necrotic areas, lower serum transaminase levels, decreased apoptosis rates, and reduced inflammatory cell infiltration, whereas Steap3‐HTG mice had the opposite phenotype. Further molecular experiments showed that Steap3 deficiency could inhibit transforming growth factor‐β–activated kinase 1 (TAK1) activation and downstream c‐Jun N‐terminal kinase (JNK) and p38 signaling during hepatic I/R injury.ConclusionsSteap3 is a mediator of hepatic I/R injury that functions by regulating inflammatory responses as well as apoptosis through TAK1‐dependent activation of the JNK/p38 pathways. Targeting hepatocytes, Steap3 may be a promising approach to protect the liver against I/R injury.

Phylogenetically conserved TAK1 participates in Branchiostoma belcheri innate immune response to LPS stimulus

Transforming growth factor-β activated kinase-1 (TAK1) is an important member of the mitogen-activated protein kinase kinase kinase (MAP3K) family, which plays an important role in animal innate immune response. However, the TAK1 gene has yet not been reported in amphioxus to date. Here, we have identified and characterized a TAK1 gene from amphioxus (Branchiostoma belcheri) (named as AmphiTAK1) with the full-length cDNA of 3479 bp, including an ORF sequence of 1905 bp, a 5′ UTR of 394 bp and a 3′ UTR of 1180 bp. Moreover, the predicted AmphiTAK1 protein contains STKc_TAK1 domain, TAB1 and TAB2/3 binding domain which are conserved among chordate, and phylogenetic analysis also shows that the AmphiTAK1 is located at the bottom of the chordate, revealing AmphiTAK1 as a new member of the TAK1 gene family. The further qRT-PCR analysis has shown that AmphiTAK1 is widely expressed in six investigated tissues (gonad, gill, hepatic cecum, intestine, muscle and notochord) of Branchiostoma belcheri, with high expression in notochord and gonad, moderate in gill and hepatic cecum. Notably, the expression level of AmphiTAK1 is significantly up-regulated after LPS stimulation. Specially, we also find that AmphiTAK1 protein can interact with AmphiTAB1 by immunoprecipitation assay. These findings reveal that AmphiTAK1 might interact with AmphiTAB1 to involve in innate immune response of Branchiostoma belcheri. Taken together, our present works provide a new insight into evolution and innate immune response mechanism of AmphiTAK1 gene in Branchiostoma belcheri.

The critical role for TAK1 in trichloroethylene-induced contact hypersensitivity in vivo and in CD4+ T cell function alteration by trichloroethylene and its metabolites in vitro

Occupational exposure to trichloroethylene (TCE) has been associated with severe, generalized contact hypersensitivity (CHS) skin disorder, which is considered a delayed-type hypersensitivity reaction mediated by antigen-specific T cells. Transforming growth factor-β activated kinase-1 (TAK1) is essential for regulating the development and effector function of T cells. We hypothesized that disrupting TAK1 activity might inhibit TCE-induced CHS response. In this study, a local lymph node assay was employed to build a CHS model induced by TCE combined with the inducible-TAK1 deletion system to study the effect of TAK1 on it. It was observed that TAK1 deficiency ameliorated the TCE-induced CHS response and was associated with defective T cell expansion and activation and IFN-γ production in vivo. Furthermore, we investigated the effects of TCE and its metabolites trichloroacetic acid (TCA) and dichloroacetic acid (DCA) on CD4+ T cell function and the effect of TAK1 on it in vitro. The results showed that TCE, TCA and DCA augmented the proliferation, activation and differentiation of CD4+ T cells through Jnk MAPK and NF-κB pathways. TAK1 deletion significantly attenuated these effects induced by TCE, TCA or DCA on CD4+ T cells. In conclusion, it is suggested that TAK1 plays a critical role both in TCE-induced CHS response in vivo and in TCE and its metabolite-induced CD4+ T cell activation in vitro. Local inhibition of TAK1 might offer a promising alternative feasible strategy for TCE-induced CHS.

Transforming growth factor-β-activating kinase 1 and its binding protein 1 participate in the innate immune responses via modulating the IMD[sbnd]NF[sbnd]κB signaling in mud crab (Scylla paramamosain)

Transforming growth factor-β-activating kinase 1 (TAK1) is essential for diverse important biological functions, such as innate immunity, development and cell survival. In the present study, the homologs of TAK1 and TAK1-binding protein 1 (TAB1) were identified and characterized from mud crab Scylla paramamosain for the first time. The full-length cDNAs of SpTAK1 and SpTAB1 were 2, 226 bp and 2, 433 bp with 1, 782 bp and 1, 533 bp open reading frame (ORF), respectively. The deduced SpTAK1 protein contained a conserved S_TKc (Serine/threonine protein kinases, catalytic) domain, and the putative SpTAB1 protein possessed a typical PP2Cc (Serine/threonine phosphatases, family 2C, catalytic) domain and a potential TAK1 docking motif. Real-time PCR analysis showed that SpTAK1 and SpTAB1 were highly expressed at early development stages, suggesting their participation in crab's development process. Moreover, the expression levels of SpTAK1 and SpTAB1 in hepatopancreas were positively stimulated after challenge with Vibro alginolyticus and Poly (I:C), implying the involvement of SpTAK1 and SpTAB1 in innate immune responses against both bacterial and viral infections. When SpTAK1 or SpTAB1 were silenced in vivo, the expression levels of two IMDNFκB signaling components (SpIKKβ and SpRelish) and six antimicrobial peptide (AMP) genes (SpALF1-5 and SpCrustin) were significantly reduced, and the bacteria clearance capacity of crabs was also markedly impaired in SpTAK1 or SpTAB1 silenced crabs. Additionally, overexpression of SpTAK1 and SpTAB1 in HEK293T cells could markedly activate the mammalian NF-κB signaling. Collectively, our results suggested that TAK1 and TAB1 regulated crab's innate immunity via modulating the IMDNFκB signaling. These findings may provide new insights into the TAK1/TAB1-mediated signaling cascades in crustaceans and pave the way for a better understanding of crustacean innate immune system.

Taraxasterol suppresses inflammation in IL-1β-induced rheumatoid arthritis fibroblast-like synoviocytes and rheumatoid arthritis progression in mice

Previous study has indicated that taraxasterol (TAR), one of bioactive pentacyclic triterpenes mainly isolated from Chinese medicine herb Taraxacum officinale, displays considerable anti-inflammatory effects in various kinds of models. However, its effects on rheumatoid arthritis (RA) have still not been elucidated. In this study, we aim to investigate its anti-inflammatory effects and underlying mechanisms of TAR against RA using both interleukin (IL)-1β-stimulated human fibroblast-like synoviocytes rheumatoid arthritis (HFLS-RA) in vitro and collagen-induced arthritis (CIA) mice in vivo. Firstly, our results demonstrated that TRA significantly suppressed the IL-1β-induced expressions of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), IL-6, and IL-8 and productions of matrix metalloproteinases (MMPs), like MMP-1 and MMP-3 in HFLS-RA in vitro. Moreover, TRA alleviated arthritis progressions and prevented inflammatory processes in the joint tissues of CIA mice in vivo. Further mechanism studies indicated that TRA blocked nuclear factor kappa B (NF-κB) activation via modulating inhibitor of kappa B (IκB), IκB kinase (IKK) and transforming growth factor-β-activated kinase 1 (TAK1). Results also demonstrated that TRA suppressed the NOD-like receptor protein 3 (NLRP3) inflammasomes through blocking expressions of NLRP3, apoptosis-associated speck-like protein containing (ASC), and caspase-1 in both IL-1β-induced HFLS-RA and CIA mice. In conclusions, current findings suggested that TRA might one of considerable therapeutic compounds for relieving rheumatoid arthritis progress via suppressing inflammations through modulating NF-κB and NLRP3 inflammasomes pathways.

Tanshinone IIA inhibits lipopolysaccharide‑induced inflammatory responses through the TLR4/TAK1/NF‑κB signaling pathway in vascular smooth muscle cells

To aim of the present study was to determine whether Tanshinone IIA (Tan IIA) inhibits lipopolysaccharide (LPS)‑induced inflammation in vascular smooth muscle cells (VSMCs) from rats and elucidate the underlying molecular mechanism. VSMCs were primarily cultured and then treated with LPS (1 µg/l) and Tan IIA (25, 50 and 100 µmol/l) for 24 h. Monocyte chemoattractant protein (MCP)‑1, interleukin (IL)‑6 and tumor necrosis factor (TNF)‑α levels were detected by ELISA and reverse transcription‑quantitative polymerase chain reaction. Nitric oxide (NO) production was measured using the Griess reaction. The expression of Toll‑like receptor 4 (TLR4), nuclear factor (NF)‑κB (p65), and inducible NO synthase (iNOS), and the phosphorylation of transforming growth factor‑β‑activated kinase 1 (TAK1) were detected by western blot analysis. Tan IIA inhibited the LPS‑induced expression of MCP‑1, IL‑6, and TNF‑α in a concentration‑dependent manner and inhibited iNOS‑mediated NO production. In addition, Tan IIA suppressed the expression of TLR4, the phosphorylation of TAK1, and the nuclear translocation of NF‑κB (p65). The anti‑TLR4 antibody and TAK1 inhibitor 5Z‑7‑oxozeaenol partially attenuated the LPS‑induced expression of proinflammatory cytokines. In conclusion, Tan IIA inhibits LPS‑induced inflammatory responses in VSMCs in vitro through the partial suppression of the TLR4/TAK1/NF‑κB signaling pathway.

PLC\u03b22 negatively regulates the inflammatory response to virus infection by inhibiting phosphoinositide-mediated activation of TAK1

Excessive or uncontrolled release of proinflammatory cytokines caused by severe viral infections often results in host tissue injury or even death. Phospholipase C (PLC)s degrade phosphatidylinositol-4, 5-bisphosphate (PI(4,5)P2) lipids and regulate multiple cellular events. Here, we report that PLCβ2 inhibits the virus-induced expression of pro-inflammatory cytokines by interacting with and inhibiting transforming growth factor-β-activated kinase 1 (TAK1) activation. Mechanistically, PI(4,5)P2 lipids directly interact with TAK1 at W241 and N245, and promote its activation. Impairing of PI(4,5)P2’s binding affinity or mutation of PIP2-binding sites on TAK1 abolish its activation and the subsequent production of pro-inflammatory cytokines. Moreover, PLCβ2-deficient mice exhibit increased expression of proinflammatory cytokines and a higher frequency of death in response to virus infection, while the PLCβ2 activator, m-3M3FBS, protects mice from severe Coxsackie virus A 16 (CVA16) infection. Thus, our findings suggest that PLCβ2 negatively regulates virus-induced pro-inflammatory responses by inhibiting phosphoinositide-mediated activation of TAK1.

Lipopolysaccharide-Induced Increase in Intestinal Permeability Is Mediated by TAK-1 Activation of IKK and MLCK/MYLK Gene

Lipopolysaccharides (LPSs) are a major component of Gram-negative bacterial cell wall and play an important role in promoting intestinal inflammatory responses. Recent studies have shown that physiologically relevant concentrations of LPS (0 to 2000 pg/mL) cause an increase in intestinal epithelial tight junction (TJ) permeability without causing cell death. However, the intracellular pathways and the mechanisms that mediate LPS-induced increase in intestinal TJ permeability remain unclear. The aim was to delineate the intracellular pathways that mediate the LPS-induced increase in intestinal permeability using invitro and invivo intestinal epithelial models. LPS-induced increase in intestinal epithelial TJ permeability was preceded by an activation of transforming growth factor-β-activating kinase-1 (TAK-1) and canonical NF-κB (p50/p65) pathways. The siRNA silencing of TAK-1 inhibited the activation of NF-κB p50/p65. The siRNA silencing of TAK-1 and p65/p50 subunit inhibited the LPS-induced increase in intestinal TJ permeability and the increase in myosin light chain kinase (MLCK) expression, confirming the regulatory role of TAK-1 and NF-κB p65/p50 in up-regulating MLCK expression and the subsequent increase in TJ permeability. The data also showed that toll-like receptor (TLR)-4/myeloid differentiation primary response (MyD)88 pathway was crucial upstream regulator of TAK-1 and NF-κB p50/p65 activation. In conclusion, activation of TAK-1 by the TLR-4/MyD88 signal transduction pathway and MLCK by NF-κB p65/p50 regulates the LPS-induced increase in intestinal epithelial TJ permeability.

Molecular Characterization, Expression Profiles, and Immunostimulation Responses of TRAF6 and TAK1 in Japanese Flounder (Paralichthys olivaceus)

Tumor necrosis factor receptor-associated factor 6 (TRAF6) and transforming growth factor-β-activated kinase 1 (TAK1) are two important adaptor molecules in Toll-like receptor (TLR) signaling pathway. In this study, TRAF6 (PoTRAF6) and TAK1 (PoTAK1) were cloned and characterized in Japanese flounder (Paralichthys olivaceus). The full-length cDNA sequence of PoTRAF6 is 1953 bp, with an open reading frame (ORF) of 1713 bp encoding a putative protein of 570 amino acids. PoTRAF6 contains one really interesting new gene (RING) domain, two zinc fingers, one coiled-coil region, and one meprin and TRAF homology (MATH) domain, which shows a high similarity to TRAF6s in other species. The full-length PoTAK1 cDNA sequence is 2086 bp, with an ORF of 1728 bp that encodes a putative protein of 575 amino acids. PoTAK1 contains a conserved serine/threonine protein kinase catalytic domain and a coiled-coil region. The promoter regions of PoTRAF6 and PoTAK1 were also analyzed to predict several potential transcription factor-binding sites. In addition, the expression patterns of these two genes were examined in developmental stages, different tissues, and challenged samples. PoTRAF6 and PoTAK1 were expressed during the whole developmental stages, and the highest expressions were in intestine and heart, respectively. In challenged embryonic cells with LPS, CpG ODN, and poly I:C, the expressions of PoTRAF6 and PoTAK1 were both up-regulated significantly. These results suggest that PoTRAF6 and PoTAK1 play crucial roles in immune responses and may be involved in the developmental process of Japanese flounder.

Enterohemorrhagic Escherichia coli Tir inhibits TAK1 activation and mediates immune evasion

ABSTRACT Many pathogens infect hosts through various immune evasion strategies. However, the molecular mechanisms by which pathogen proteins modulate and evade the host immune response remain unclear. Enterohemorrhagic Escherichia coli (EHEC) is a pathological strain that can induce mitogen-activated protein (MAP) kinase (Erk, Jnk and p38 MAPK) and NF-κB pathway activation and proinflammatory cytokine production, which then causes diarrheal diseases such as hemorrhagic colitis and hemolytic uremic syndrome. Transforming growth factor β-activated kinase-1 (TAK1) is a key regulator involved in distinct innate immune signalling pathways. Here we report that EHEC translocated intimin receptor (Tir) protein inhibits the expression of EHEC-induced proinflammatory cytokines by interacting with the host tyrosine phosphatase SHP-1, which is dependent on the phosphorylation of immunoreceptor tyrosine-based inhibition motifs (ITIMs). Mechanistically, the association of EHEC Tir with SHP-1 facilitated the recruitment of SHP-1 to TAK1 and inhibited TAK1 phosphorylation, which then negatively regulated K63-linked polyubiquitination of TAK1 and downstream signal transduction. Taken together, these results suggest that EHEC Tir negatively regulates proinflammatory responses by inhibiting the activation of TAK1, which is essential for immune evasion and could be a potential target for the treatment of bacterial infection.

Synthesis and anti-tumor activity of imidazopyrazines as TAK1 inhibitors

Transforming growth factor-β activated kinase-1 (TAK1) is a potential therapeutic target for cancers and inflammatory diseases. We synthesized a series of novel imidazopyrazine derivatives, which were found to exhibit potent inhibitory effect against TAK1. Compound 22a, which possesses a good pharmacokinetic profile, showed excellent in vitro kinase activity and significant in vivo efficacy in mice xenografted with SW620, a KRAS-dependent colon cancer cell line.

NG25, a novel inhibitor of TAK1, suppresses KRAS-mutant colorectal cancer growth in vitro and in vivo.

KRAS mutations are one of the most prevalent genetic alterations in colorectal cancer (CRC). Although directly targeting KRAS still is a challenge in anti-cancer therapies, alternatively inhibiting KRAS related signaling pathways has been approached effectively. Here we firstly reported that MAP kinase, transforming growth factor-β-activated kinase 1 (TAK1), commonly expressed in CRC cell lines and significantly associated with KRAS mutation status. Inhibition of TAK1 by the small molecular inhibitor NG25 could inhibit CRC cells proliferation in vitro and in vivo, especially in KRAS-mutant cells. NG25 induced caspase-dependent apoptosis in KRAS-mutant cells and in orthotopic CRC mouse models by regulating the B-cell lymphoma-2 (Bcl-2) family and the inhibitor of apoptosis protein (IAP) family. Besides inhibiting molecules downstream of MAPK, including ERK, JNK and p38 phosphorylation, NG25 could block NF-κB activation in KRAS-mutant cells. As a target gene of NF-κB, down-regulated XIAP expression may be not only involved in apoptosis induced by NG25, but also reducing the formation of TAK1-XIAP complex that can activate TAK1 downstream signaling pathways, which forms a positive feedback loop to further induce apoptosis in KRAS-mutant CRC cells. Together, these findings indicated that TAK1 is an important kinase for survival of CRCs harboring KRAS mutations, and that NG25 may be a potential therapeutic strategy for KRAS-mutant CRC.

Resibufogenin suppresses transforming growth factor-β-activated kinase 1-mediated nuclear factor-κB activity through protein kinase C-dependent inhibition of glycogen synthase kinase 3.

Resibufogenin (RB), one of the major active compounds of the traditional Chinese medicine Chansu, has received considerable attention for its potency in cancer therapy. However, the anticancer effects and the underlying mechanisms of RB on pancreatic cancer remain elusive. Here, we found that RB inhibited the viability and induces caspase‐dependent apoptosis in human pancreatic cancer cells Panc‐1 and Aspc. Resibufogenin‐induced apoptosis was through inhibition of constitutive nuclear factor‐κB (NF‐κB) activity and its target genes’ expression, which was caused by downregulation of transforming growth factor‐β‐activated kinase 1 (TAK1) levels and suppression of IκB kinase activity in Panc‐1 and Aspc cells. This induction of TAK1‐mediated NF‐κB inactivation by RB was associated with increased glycogen synthase kinase‐3 (GSK‐3) phosphorylation and subsequent suppression of its activity. Moreover, RB‐induced GSK‐3 phosphorylation/inactivation acted through activation of protein kinase C but not Akt. Finally, RB suppressed human pancreatic tumor xenograft growth in athymic nude mice. Thus, our findings reveal a novel mechanism by which RB suppresses TAK1‐mediated NF‐κB activity through protein kinase C‐dependent inhibition of GSK‐3. Our findings provide a rationale for the potential application of RB in pancreatic cancer therapy.

Effect of deubiquitinase USP8 on hypoxia/reoxygenation‑induced inflammation by deubiquitination of TAK1 in renal tubular epithelial cells.

Intermittent hypoxia/reoxygenation (IHR), characterized by repeated episodes of hypoxia interspersed with periods of reoxygenation, has been found to induce pro‑inflammatory cytokine production and is increasingly recognized as a major pathophysiological factor in various disease processes with distinct cell and molecular responses. The present study is the first, to the best of our knowledge, to investigate the effects of ubiquitin‑specific peptidase 8 (USP8) on IHR‑induced inflammation in renal tubular epithelial cells and examine the underlying mechanism. Following transfection of plasmids, HK‑2 and TCMK‑1 cells were incubated for eight cycles of IHR treatment including 3 h of hypoxic incubation followed by 3 h of normoxic culture. It was demonstrated that the expression of USP8 was decreased in IHR conditions but not in normoxic or continuous hypoxic conditions. In addition, IHR‑induced inflammation was suppressed in USP8‑overexpressinh renal tubular epithelial cells, and the silencing of USP8 markedly aggravated inflammation. Furthermore, it was found that the overexpression of USP8 inhibited the IHR‑induced activation of nuclear factor‑κB and it was demonstrated that USP8 interacted with transforming growth factor‑β‑activated kinase‑1 (TAK1) and deubiquitinated the K63‑linked ubiquitination of TAK1. Taken together, the results demonstrated the role of USP8 in IHR‑induced inflammation and suggested USP8 as a potential and specific therapeutic target for IHR‑related diseases.

Retrospective screening of microarray data to identify candidate IFN-inducible genes in a HTLV-1 transformed model.

HuT-102 cells are considered one of the most representable human T-lymphotropic virus 1 (HTLV-1)-infected cell lines for studying adult T-cell lymphoma (ATL). In our previous studies, genome-wide screening was performed using the GeneChip system with Human Genome Array U133 Plus 2.0 for transforming growth factor-β-activated kinase 1 (TAK1)-, interferon regulatory factor 3 (IRF3)- and IRF4-regulated genes to demonstrate the effects of interferon-inducible genes in HuT-102 cells. Our previous findings demonstrated that TAK1 induced interferon inducible genes via an IRF3-dependent pathway and that IRF4 has a counteracting effect. As our previous data was performed by manual selection of common interferon-related genes mentioned in the literature, there has been some obscure genes that have not been considered. In an attempt to maximize the outcome of those microarrays, the present study reanalyzed the data collected in previous studies through a set of computational rules implemented using ‘R’ software, to identify important candidate genes that have been missed in the previous two studies. The final list obtained consisted of ten genes that are highly recommend as potential candidate for therapies targeting the HTLV-1 infected cancer cells. Those genes are ATM, CFTR, MUC4, PARP14, QK1, UBR2, CLEC7A (Dectin-1), L3MBTL, SEC24D and TMEM140. Notably, PARP14 has gained increased attention as a promising target in cancer cells.

The interaction of TAK1 and TAB1 enhances LPS-induced cytokine release via modulating NF-κB activation (Larimichthys crocea)

Transforming growth factor-β-activating kinase 1 (TAK1) is triggered by foreign pathogenic infection and involves in proinflammatory response through the activation of nuclear factor-κB (NF-κB), which is specifically regulated by TAK1-binding protein 1 (TAB1). However, the expression and regulatory characterizations of TAK1 and TAB1 in fish immune response remain largely unknown. In the present study, the cDNA sequences of TAK1 (LcTAK1) and TAB1 (LcTAB1) were identified from large yellow croaker, Larimichthys crocea. The open reading frame (ORF) of LcTAK1 was 1725 bp in length, encoding 574 amino acids. The putative LcTAK1 protein contained a protein kinase domain and a C-terminal coiled-coil region. The ORF of LcTAB1 was 1518 bp encoding 505 amino acids. And a typical PP2Cc domain and a conserved sequence motif (PYVDFSQFYLLWGSDH) at C-terminal were identified in the predicted LcTAB1 protein. Multiple alignments showed that LcTAK1 shared 74.0–97.9% and LcTAB1 shared 37.4–95.8% sequence identities with TAK1 and TAB1 proteins from other species, respectively. Quantitative PCR analysis indicated that both LcTAK1 and LcTAB1 were broadly expressed in all examined tissues, with the most predominant expression in brain and the weakest expression in muscle, respectively. Subcellular localization revealed that both LcTAK1 and LcTAB1 expressed in the cytoplasm. In addition, LcTAK1 transcripts increased significantly in LCK cells after flagellin, LPS and poly I:C stimulation while LcTAB1 enhanced greatly after LPS and poly I:C challenge. Furthermore, the roles of them in NF-κB activation were investigated by overexpression of LcTAK1 and LcTAB1 in HEK293T cells. Our results revealed that NF-κB luciferase promoter expression could not be induced by overexpression of LcTAK1 or LcTAB1 alone, however, it could be induced by co-expression of LcTAK1 and LcTAB1 together. Moreover, the roles of LcTAK1 and LcTAB1 in immune response analysis showed that NF-κB activation enhanced significantly in co-overexpressed HEK293T cells following LPS and poly I:C stimulation. However, the expression levels of tumor necrosis factor (TNF)-α, Interleukin-6 (IL-6) and IL-8 were induced only after LPS challenge (p < .05). These findings suggested that the TAK1-TAB1 complex of large yellow croaker might play an important role in pro-inflammatory cytokines and chemokine release after LPS stimulation via inducing NF-κB activation.

TAB3 upregulates Survivin expression to promote colorectal cancer invasion and metastasis by binding to the TAK1-TRAF6 complex.

Transforming growth factor-β-activated kinase 1 (TAK1)-binding protein 3 (TAB3) is involved in cancer proliferation and metastasis, but its role in colorectal cancer remains unclear. In this study, we demonstrated that TAB3 is upregulated in colorectal cancer tissues and that high TAB3 levels correlated with tumor metastasis and a poor prognosis in colorectal cancer. In addition, TAB3 knockdown decreased Survivin expression and suppressed colorectal cancer cell migration and invasion in vitro, and reduced liver metastasis in vivo. Importantly, we found that TAB3 regulated Survivin expression by activating the NF-κB pathway through the formation of the TAK1-TAB3-TRAF6 complex. These findings suggest TAB3 may be a useful prognostic biomarker in colorectal cancer and a target for treatment of metastatic colorectal cancer.

Abstract 468: TAB2 is Molecular Switch That Critically Regulates Myocardial Survival and Necroptosis

Our recent study identified a key role for TAK1 (transforming growth factor β activated kinase-1) in regulating myocardial remodeling and heart failure propensity by antagonizing necroptosis, also termed programmed necrosis ( Circulation 2014;130:2162-2172). TAB2 (TAK1 binding protein-2) is an adaptor protein that regulates TAK1 activation and downstream signaling. Here we tested the hypothesis that TAB2 functions as a critical regulator of myocardial necroptosis and pathological remodeling. We found that both TAB2 and TAK1 were up-regulated during compensatory cardiac hypertrophy but down-regulated in end-stage heart failure. Genetic ablation of TAB2 in cardiomyocytes, but not other TAK1 binding proteins TAB1 or TAB2, markedly increased necroptosis in response to TNFα stimulation. Genetic deletion of RIP3 (receptor interacting protein-3), a key regulator of necroptosis, also largely blocked cell death in TAB2-deficent cells, further confirming the role of TAB2 in regulating necroptotic cell death. Mechanistically, our data showed that TAB2 functions as a molecular switch that tightly regulates TAK1-RIP1 interaction (pro-survival) and the RIP1-RIP3 necrosome formation (pro-necroptosis). We further showed that loss of TAB2 promotes necroptosis in cardiomyocytes via two independent mechanisms: acutely through the induction of RIP1-RIP3 necrosome and later through inhibition of the NFκB pathway. Importantly, cardiac-specific ablation of TAB2 in mice showed enhanced pathological remodeling with massive fibrosis and necroptosis, and the TAB2-deficient mice gradually developed dilated cardiomyopathy and heart failure starting 2 months old. Moreover, the TAB2-deficient mice are also predisposed to heart failure after pathological stress by pressure overload or myocardial infarction, suggesting a protective role of TAB2 in cardiac stress response. These results strongly indicate that TAB2 functions as a molecular switch that critically regulates the pro-survival TAK1 signaling and the necroptosis machinery, thus playing a critical role in myocardial survival and stress response. The TAB2-TAK1 signaling network may serve as a novel therapeutic target in heart disease and other pathological conditions driven by necroptosis.

TAK1 inhibition attenuates both inflammation and fibrosis in experimental pneumoconiosis

Pneumoconiosis, caused by inhalation of mineral dusts, is a major occupational disease worldwide. Currently, there are no effective drugs owing to a lack of potential therapeutic targets during either the inflammation or fibrosis molecular events in pneumoconiosis. Here, we performed microarrays to identify aberrantly expressed genes in the above molecular events in vitro and found a hub gene transforming growth factor-β-activated kinase 1 (TAK1), which was highly expressed and activated in pneumoconiosis patients as well as silica-exposed rats with experimental pneumoconiosis. Genetic modulation of TAK1 by CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9, RNA interference and overexpression indicated the important role of TAK1 in both inflammation and fibrosis in experimental pneumoconiosis. To achieve pharmacological TAK1 inhibition, we virtually screened out a natural product resveratrol, which targeted TAK1 at both N161 and A107 residues, and significantly inhibited TAK1 activation to attenuate inflammation and fibrosis in vitro. Consistently, in vivo prevention and intervention studies showed that resveratrol could inhibit pulmonary inflammation and fibrosis in silica-exposed rats.