Transforming Growth Factor-β-activated Kinase 1 Research Articles

Hepatocyte-specific deletion of Nlrp6 in mice exacerbates the development of non-alcoholic steatohepatitis

ObjectivePrevious studies have established that deficiency in Nucleotide-binding and oligomerization domain (NOD)-like receptor family pyrin domain containing 6 (Nlrp6) changes the configuration of the gut microbiota, which leads to hepatic steatosis. Here, we aimed to determine the hepatic function of Nlrp6 in lipid metabolism and inflammation and its role in the development of non-alcoholic steatohepatitis (NASH). MethodsNlrp6Loxp/Loxp and hepatocyte-specific Nlrp6-knockout mice were fed a high-fat diet (HFD) or methionine-choline deficient (MCD) diet to induce fatty liver or steatohepatitis, respectively. Primary hepatocytes were isolated to further explore the underlying mechanisms in vitro. In addition, we used adenovirus to overexpress Nlrp6 in ob/ob mice to demonstrate its role in NASH. ResultsHepatic Nlrp6 expression was downregulated in NASH patients and in obese mice. Hepatocyte-specific Nlrp6 deficiency promoted HFD- or MCD diet-induced lipid accumulation and inflammation, whereas Nlrp6 overexpression in ob/ob mice had beneficial effects. In vitro studies demonstrated that knockdown of Nlrp6 aggravated hepatic steatosis and inflammation in hepatocytes, but its overexpression markedly attenuated these abnormalities. Moreover, both in vitro and in vivo study demonstrated that Nlrp6 inhibited Cd36‐mediated lipid uptake. Nlrp6 deficiency-enhanced fatty acid uptake was blocked by a Cd36 inhibitor in hepatocytes. Nlrp6 ablation increased the expression of proinflammatory cytokines, likely as a result of increased NF-κB phosphorylation and activation. Mechanistically, Nlrp6 promoted the degradation of transforming growth factor-β-activated kinase 1 (TAK1)-binding protein 2/3 (TAB2/3) via a lysosomal-dependent pathway, which suppressed NF-κB activation. ConclusionsNlrp6 may play a key role in the pathological process of NASH by inhibiting Cd36 and NF-κB pathways. It may be a potential therapeutic target for NASH.

Olea europaea Suppresses Inflammation by Targeting TAK1-Mediated MAP Kinase Activation.

Possessing a variety of medicinal functions, Olea europaea L. is widely cultivated across the world. However, the anti-inflammatory mechanism of Olea europaea is not yet fully elucidated. In this study, how the methanol extract of the leaves of Olea europaea (Oe-ME) can suppress in vitro inflammatory responses was examined in terms of the identification of the target protein. RAW264.7 and HEK293T cells were used to study macrophage-mediated inflammatory responses and to validate the target protein using PCR, immunoblotting, nuclear fraction, overexpression, and cellular thermal shift assay (CETSA) under fixed conditions. Oe-ME treatment inhibited the mRNA expression levels of cyclooxygenase (COX)-2, matrix metallopeptidase (MMP)-9, and intercellular adhesion molecule-1 (ICAM-1) in activated RAW264.7 cells. Oe-ME diminished the activation of activator protein (AP)-1 and the phosphorylation of its upstream signaling cascades, including extracellular signal regulated kinase (ERK), mitogen-activated protein kinase kinase 1/2 (MEK1/2), c-Jun N-terminal kinase (JNK), mitogen-activated protein kinase kinase 3/6 (MKK3/6), p38, MKK7, and transforming growth factor-β-activated kinase 1 (TAK1), in stimulated-RAW264.7 cells. Overexpression and CETSA were carried out to verify that TAK1 is the target of Oe-ME. Our results suggest that the anti-inflammatory effect of Oe-ME could be attributed to its control of posttranslational modification and transcription of TAK1.

TAK1 inhibition improves myoblast differentiation and alleviates fibrosis in a mouse model of Duchenne muscular dystrophy.

BackgroundTransforming growth factor‐β‐activated kinase 1 (TAK1) plays a key role in regulating fibroblast and myoblast proliferation and differentiation. However, the TAK1 changes associated with Duchenne muscular dystrophy (DMD) are poorly understood, and it remains unclear how TAK1 regulation could be exploited to aid the treatment of this disease.MethodsMuscle biopsies were obtained from control donors or DMD patients for diagnosis (n = 6 per group, male, 2–3 years, respectively). Protein expression of phosphorylated TAK1 was measured by western blot and immunofluorescence analysis. In vivo overexpression of TAK1 was performed in skeletal muscle to assess whether TAK1 is sufficient to induce or aggravate atrophy and fibrosis. To explore whether TAK1 inhibition protects against muscle damage, mdx (loss of dystrophin) mice were treated with adeno‐associated virus (AAV)‐short hairpin TAK1 (shTAK1) or NG25 (a TAK1 inhibitor). Serum analysis, skeletal muscle performance and histology, muscle contractile function, and gene and protein expression were performed.ResultsWe found that TAK1 was activated in the dystrophic muscles of DMD patients (n = 6, +72.2%, P < 0.001), resulting in fibrosis ( +65.9% for fibronectin expression, P < 0.001) and loss of muscle fibres (−32.5%, P < 0.01). Moreover, TAK1 was activated by interleukin‐1β, tumour necrosis factor‐α, and transforming growth factor‐β1 (P < 0.01). Overexpression of TAK1 by AAV vectors further aggravated fibrosis (n = 8, +39.6% for hydroxyproline content, P < 0.01) and exacerbated muscle wasting (−31.6%, P < 0.01) in mdx mice; however, these effects were reversed in mdx mice by treatment with AAV‐short hairpin TAK1 (shTAK1) or NG25 (a TAK1 inhibitor). The molecular mechanism underlying these effects may be related to the prevention of TAK1‐mediated transdifferentiation of myoblasts into fibroblasts, thereby reducing fibrosis and increasing myoblast differentiation.ConclusionsOur findings show that TAK1 activation exacerbated fibrosis and muscle degeneration and that TAK1 inhibition can improve whole‐body muscle quality and the function of dystrophic skeletal muscle. Thus, TAK1 inhibition may constitute a novel therapy for DMD.

SHP-1 suppresses endotoxin-induced uveitis by inhibiting the TAK1/JNK pathway.

We investigated how Src‐homology 2‐domain phosphatase‐1 (SHP‐1) regulates the inflammatory response in endotoxin‐induced uveitis (EIU), and the signalling pathways involved. One week after intravitreal injection of short hairpin RNA targeting SHP‐1 or SHP‐1 overexpression lentivirus in rats, we induced ocular inflammation with an intravitreal injection of lipopolysaccharide (LPS). We then assessed the extent of inflammation and performed full‐field electroretinography. The concentrations and retinal expression of various inflammatory mediators were examined with enzyme‐linked immunosorbent assays and Western blotting, respectively. SHP‐1 overexpression and knockdown were induced in Müller cells to study the role of SHP‐1 in the LPS‐induced inflammatory response in vitro. Retinal SHP‐1 expression was up‐regulated by LPS. SHP‐1 knockdown exacerbated LPS‐induced retinal dysfunction and increased the levels of proinflammatory mediators in the retina, which was abrogated by a c‐Jun N‐terminal kinase (JNK) inhibitor (SP600125). SHP‐1 overexpression had the opposite effects. In Müller cells, the LPS‐induced inflammatory response was enhanced by SHP‐1 knockdown and suppressed by SHP‐1 overexpression. SHP‐1 negatively regulated the activation of the transforming growth factor‐β‐activated kinase‐1 (TAK1)/JNK pathway, but not the nuclear factor‐κB pathway. These results indicate that SHP‐1 represses EIU, at least in part, by inhibiting the TAK1/JNK pathway and suggest that SHP‐1 is a potential therapeutic target for uveitis.

TRIM31 promotes apoptosis via TAK1-mediated activation of NF-κB signaling in sepsis-induced myocardial dysfunction

ABSTRACT Sepsis is a major condition caused by an overwhelming inflammatory response to an infection. Sepsis-induced myocardial dysfunction (SIMD) is a common complication in septic patients and a major predictor of morbidity and mortality. Here, we investigated the role of tripartite motif 31 (TRIM31) protein in sepsis progression in vitro and in vivo. Quantitative real-time PCR and western blot were used to detect the expression levels of relative genes and proteins. Cell proliferation and apoptosis were evaluated to determine cell viability. H&E and IHC staining were performed to examine morphological and pathological changes in mice. ELISA assay was used to detect inflammatory factors. TRIM31 was upregulated in septic patients compared with normal people. TRIM31 depletion reduced LPS-induced apoptosis whereas TRIM31 overexpression-elevated LPS-induced apoptosis. Furthermore, TRIM31 interacted with and ubiquitinated transforming growth factor-β-activated kinase-1 (TAK1), resulting in TAK1 activation and subsequent induction of NF-κB signaling. Of note, Trim31 depletion or blockade by PDTC treatment inhibited LPS-induced apoptosis in vivo. In conclusion, TRIM31 played an important role in SIMD by activating TAK1-mediated NF-κB signaling pathway.

TAK1: a potent tumour necrosis factor inhibitor for the treatment of inflammatory diseases.

Aberrant tumour necrosis factor (TNF) signalling is a hallmark of many inflammatory diseases including rheumatoid arthritis (RA), irritable bowel disease and lupus. Maladaptive TNF signalling can lead to hyper active downstream nuclear factor (NF)-κβ signalling in turn amplifying a cell's inflammatory response and exacerbating disease. Within the TNF intracellular inflammatory signalling cascade, transforming growth factor-β-activated kinase 1 (TAK1) has been shown to play a critical role in mediating signal transduction and downstream NF-κβ activation. Owing to its role in TNF inflammatory signalling, TAK1 has become a potential therapeutic target for the treatment of inflammatory diseases such as RA. This review highlights the current development of targeting the TNF-TAK1 signalling axis as a novel therapeutic strategy for the treatment of inflammatory diseases.

A potential therapeutic effect of catalpol in Duchenne muscular dystrophy revealed by binding with TAK1.

BackgroundDuchenne muscular dystrophy (DMD) is a progressive muscle disease caused by the loss of dystrophin, which results in inflammation, fibrosis, and the inhibition of myoblast differentiation in skeletal muscle. Catalpol, an iridoid glycoside, improves skeletal muscle function by enhancing myogenesis; it has potential to treat DMD. We demonstrate the positive effects of catalpol in dystrophic skeletal muscle.Methods mdx (loss of dystrophin) mice (n = 18 per group) were treated with catalpol (200 mg/kg) for six consecutive weeks. Serum analysis, skeletal muscle performance and histology, muscle contractile function, and gene and protein expression were performed. Molecular docking and ligand–target interactions, RNA interference, immunofluorescence, and plasmids transfection were utilized to explore the protective mechanism in DMD by which catalpol binding with transforming growth factor‐β–activated kinase 1 (TAK1) in skeletal muscle.ResultsSix weeks of catalpol treatment improved whole‐body muscle health in mdx mice, which was characterized by reduced plasma creatine kinase (n = 18, −35.1%, P < 0.05) and lactic dehydrogenase (n = 18, −10.3%, P < 0.05) activity. These effects were accompanied by enhanced grip strength (n = 18, +25.4%, P < 0.05) and reduced fibrosis (n = 18, −29.0% for hydroxyproline content, P < 0.05). Moreover, catalpol treatment protected against muscle fatigue and promoted muscle recovery in the tibialis anterior (TA) and diaphragm (DIA) muscles (n = 6, +69.8%, P < 0.05 and + 74.8%, P < 0.001, respectively), which was accompanied by enhanced differentiation in primary myoblasts from DMD patients (n = 6, male, mean age: 4.7 ± 1.9 years) and mdx mice. In addition, catalpol eliminated p‐TAK1 overexpression in mdx mice (n = 12, −21.3%, P < 0.05) and primary myoblasts. The catalpol‐induced reduction in fibrosis and increased myoblast differentiation resulted from the inhibition of TAK1 phosphorylation, leading to reduced myoblast trans‐differentiation into myofibroblasts. Catalpol inhibited the phosphorylation of TAK1 by binding to TAK1, possibly at Asp‐206, Thr‐208, Asn‐211, Glu‐297, Lys‐294, and Tyr‐293.ConclusionsOur findings show that catalpol and TAK1 inhibitors substantially improve whole‐body muscle health and the function of dystrophic skeletal muscles and may provide a novel therapy for DMD.

Apolipoprotein E Signals via TLR4 to Induce CXCL5 Secretion by Asthmatic Airway Epithelial Cells.

The primary function of APOE (apolipoprotein E) is to mediate the transport of cholesterol- and lipid-containing lipoprotein particles into cells by receptor-mediated endocytosis. APOE also has pro- and antiinflammatory effects, which are both context and concentration dependent. For example, Apoe-/- mice exhibit enhanced airway remodeling and hyperreactivity in experimental asthma, whereas increased APOE levels in lung epithelial lining fluid induce IL-1β secretion from human asthmatic alveolar macrophages. However, APOE-mediated airway epithelial cell inflammatory responses and signaling pathways have not been defined. Here, RNA sequencing of human asthmatic bronchial brushing cells stimulated with APOE identified increased expression of mRNA transcripts encoding multiple proinflammatory genes, including CXCL5 (C-X-C motif chemokine ligand 5), an epithelial-derived chemokine that promotes neutrophil activation and chemotaxis. We subsequently characterized the APOE signaling pathway that induces CXCL5 secretion by human asthmatic small airway epithelial cells (SAECs). Neutralizing antibodies directed against TLR4 (Toll-like receptor 4), but not TLR2, attenuated APOE-mediated CXCL5 secretion by human asthmatic SAECs. Inhibition of TAK1 (transforming growth factor-β-activated kinase 1), IκKβ (inhibitor of nuclear factor κ B kinase subunit β), TPL2 (tumor progression locus 2), and JNK (c-Jun N-terminal kinase), but not p38 MAPK (mitogen-activated protein kinase) or MEK1/2 (MAPK kinase 1/2), attenuated APOE-mediated CXCL5 secretion. The roles of TAK1, IκKβ, TPL2, and JNK in APOE-mediated CXCL5 secretion were verified by RNA interference. Furthermore, RNA interference showed that after APOE stimulation, both NF-κB p65 and TPL2 were downstream of TAK1 and IκKβ, whereas JNK was downstream of TPL2. In summary, elevated levels of APOE in the airway may activate a TLR4/TAK1/IκKβ/NF-κB/TPL2/JNK signaling pathway that induces CXCL5 secretion by human asthmatic SAECs. These findings identify new roles for TLR4 and TPL2 in APOE-mediated proinflammatory responses in asthma.

Long non‑coding RNA MCM3AP‑AS1 drives ovarian cancer progression via the microRNA‑143‑3p/TAK1 axis.

The long non-coding RNA (lncRNA) MCM3AP antisense 1 (MCM3AP-AS1) has previously been shown to be a key regulator of multiple types of cancer; however whether it is important in the context of ovarian cancer (OC) is uncertain. The present study determined that MCM3AP-AS1 expression in samples from patients with OC was significantly increased, and was associated with tumor stage, presence of lymph node metastases and poorer overall survival. The role of this lncRNA was investigated in vitro, and it was observed that knockdown of MCM3AP-AS1 impaired OC cell proliferation, migration and colony formation. Similarly, it disrupted tumor growth in vivo. The present study further determined that MCM3AP-AS1 was able to directly interact with microRNA (miRNA or miR)-143-3p as a competing endogenous (ce)RNA for this miRNA, thereby regulating the expression of transforming growth factor-β-activated kinase 1 (TAK1), a known target of miR-143-3p in OC. Consistent with this, inhibition of miR-143-3p was sufficient to partially reverse the effects of MCM3AP-AS1-knockdown, which inhibited the proliferation, migration and invasion of OC cells. Together, these results indicate that MCM3AP-AS1 serves as an oncogenic lncRNA in OC by binding to miR-143-3p and thereby promoting TAK1 expression, and suggest that this lncRNA may be a possible target for therapy in OC.

TLR13, TLR22, TRAF6, and TAK1 in the soiny mullet (Liza haematocheila): Molecular characterization and expression profiling analysis

Toll-like receptors (TLRs) and their associated signaling pathways play pivotal roles in the immune response to invading pathogens. Here, TLR13, TLR22, tumor necrosis factor receptor-associated factor 6 (TRAF6), and transforming growth factor-β-activated kinase1 (TAK1) were characterized in the soiny mullet (Liza haematocheila), representative mugilid species that is widely cultured in Asia. The four mullet genes, which shared characteristic features with their counterparts in other teleosts, were ubiquitously expressed in all of the examined tissues, albeit with different expression patterns. Following Streptococcus dysgalactiae infection, the four genes were upregulated to different degrees in various mullet tissues. These results indicated that the four genes were involved in the mullet immune response to bacterial infection. To the best of our knowledge, this is the first characterization of these four genes in mullet. Our results provide a basis for future studies of TLR signaling pathways in mullet, as well as for similar studies in other mugilids.

Hepatocyte-specific TAK1 deficiency drives RIPK1 kinase-dependent inflammation to promote liver fibrosis and hepatocellular carcinoma

Transforming growth factor β-activated kinase1 (TAK1) encoded by the gene MAP3K7 regulates multiple important downstream effectors involved in immune response, cell death, and carcinogenesis. Hepatocyte-specific deletion of TAK1 in Tak1ΔHEP mice promotes liver fibrosis and hepatocellular carcinoma (HCC) formation. Here, we report that genetic inactivation of RIPK1 kinase using a kinase dead knockin D138N mutation in Tak1ΔHEP mice inhibits the expression of liver tumor biomarkers, liver fibrosis, and HCC formation. Inhibition of RIPK1, however, has no or minimum effect on hepatocyte loss and compensatory proliferation, which are the recognized factors important for liver fibrosis and HCC development. Using single-cell RNA sequencing, we discovered that inhibition of RIPK1 strongly suppresses inflammation induced by hepatocyte-specific loss of TAK1. Activation of RIPK1 promotes the transcription of key proinflammatory cytokines, such as CCL2, and CCR2+ macrophage infiltration. Our study demonstrates the role and mechanism of RIPK1 kinase in promoting inflammation, both cell-autonomously and cell-nonautonomously, in the development of liver fibrosis and HCC, independent of cell death, and compensatory proliferation. We suggest the possibility of inhibiting RIPK1 kinase as a therapeutic strategy for reducing liver fibrosis and HCC development by inhibiting inflammation.

Estrogen downregulates TAK1 expression in human fibroblast-like synoviocytes and in a rheumatoid arthritis model.

Transforming growth factor β-activated kinase-1 (TAK1), a member of the mitogen-activated protein kinase family, plays a key role in the pathogenesis and progression of rheumatoid arthritis (RA). Estrogen has been previously reported to delay arthritis progression. However, the exact association between TAK1 and estrogen remains elusive. The present study demonstrated that TAK1 was upregulated in synoviocytes of patients with RA compared with patients with osteoarthritis and healthy controls. In addition, TAK1 was also expressed in cultured fibroblast-like synoviocytes (FLS), and its levels decreased significantly in 17β-estradiol (E2)-treated cells in a dose-dependent manner. Furthermore, administration of E2 significantly decreased TAK1 expression and attenuated the development of collagen-induced arthritis (CIA). Taken together, the findings of the present study suggested that E2 mediates a decrease of TAK1 in both FLS and CIA, which subsequently results in a suppression of the pathological process of CIA. Therefore, estrogen may serve as a potential therapeutic agent for the treatment of RA by targeting TAK1.

Isoprenylcysteine Carboxyl Methyltransferase and Its Substrate Ras Are Critical Players Regulating TLR-Mediated Inflammatory Responses.

In this study, we investigated the functional role of isoprenylcysteine carboxyl methyltransferase (ICMT) and its methylatable substrate Ras in Toll-like receptor (TLR)-activated macrophages and in mouse inflammatory disease conditions. ICMT and RAS expressions were strongly increased in macrophages under the activation conditions of TLRs by lipopolysaccharide (LPS, a TLR4 ligand), pam3CSK (TLR2), or poly(I:C) (TLR3) and in the colons, stomachs, and livers of mice with colitis, gastritis, and hepatitis. The inhibition and activation of ICMT and Ras through genetic and pharmacological approaches significantly affected the activation of interleukin-1 receptor-associated kinase (IRAK)s, tumor necrosis factor receptor associated factor 6 (TRAF6), transforming growth factor-β-activated kinase 1 (TAK1), mitogen-activated protein kinase (MAPK), and MAPK kinases (MAPKKs); translocation of the AP-1 family; and the expressions of inflammation-related genes that depend on both MyD88 and TRIF. Interestingly, the Ras/ICMT-mediated inflammatory reaction critically depends on the TIR domains of myeloid differentiation primary response 88 (MyD88) and TIR-domain-containing adapter-inducing interferon-β (TRIF). Taken together, these results suggest that ICMT and its methylated Ras play important roles in the regulation of inflammatory responses through cooperation with the TIR domain of adaptor molecules.

Microglial-specific depletion of TAK1 is neuroprotective in the acute phase after ischemic stroke

Transforming growth factor-β-activated kinase 1 (TAK1) is upregulated after cerebral ischemia and contributes to an aggravation of brain injury. TAK1 acts as a key regulator of NF-ΚB and the MAP kinases JNK and p38 and modulates post-ischemic neuroinflammation and apoptosis. Microglia are the main TAK1-expressing immunocompetent cells of the brain. However, little is known about the function and regulation of microglial TAK1 after cerebral ischemia. Tamoxifen-dependent conditional depletion of TAK1 in microglial cells was induced in Cx3cr1creER-Tak1fl/fl mice. The creER-negative Tak1fl/fl mice and vehicle-treated (corn oil) mice served as control groups. A transient intraluminal middle cerebral artery occlusion of 30 min followed by 6 h and 72 h of reperfusion was performed in male mice. Oxygen-glucose-deprivation (OGD) was performed with primary cortical glial cell cultures to examine the effect of microglial-specific and general (5Z-7-Oxozeaenol) TAK1 inhibition after different reperfusion times (1 h, 6 h, and 72 h). Cx3cr1creER-Tak1fl/fl mice showed reduced infarct sizes and improved neurological outcomes compared to the control group. The mRNA and protein levels of pro-inflammatory Il1b/IL-1β and Tnf/TNF-α in the peri-infarct zones of microglial-specific TAK1-depleted mice were significantly reduced. Furthermore, TAK1 depletion in vitro led to reduced cell death rates after OGD. Moreover, hypoxia-mediated activation of TAK1 and its downstream signalling proteins, JNK and p38, were dampened by microglial TAK1 depletion. In contrast, 5Z-7-Oxozeaenol-induced pharmacological inhibition of TAK1 completely diminished MAPK-signalling including the kinases JNK and p38 in all cells. Microglial TAK1 depletion abrogates post-ischemic neuroinflammation and apoptosis in the acute phase, hence might be considered as a potential target in the treatment of cerebral hypoxia.Key messagesTAK1 is activated after cerebral ischemia and induces MAP kinases p38 and JNK.Activated TAK1 increases apoptosis rate and the level pro-inflammatory cytokines IL-1β and TNF-α.Microglial cells seem to be the main source of TAK1-mediated post-ischemic neuroinflammation.Microglial-specific TAK1-depletion mediates sustainable neuroprotective effects, which might be superior to global TAK1 inhibition.

Suppression of peripheral NGF attenuates neuropathic pain induced by chronic constriction injury through the TAK1-MAPK/NF-\u03baB signaling pathways

BackgroundAnti-nerve growth factor (NGF) monoclonal antibodies (anti-NGF mAbs) have been reported to significantly attenuate pain, but the mechanism involved has not been fully elucidated, and the serious adverse events associated with mAbs seriously limit their clinical use. This study further investigated the mechanism by which peripheral NGF is involved in neuropathic pain and found safe, natural compounds that target NGF to attenuate neuropathic pain.MethodsNociception was assessed by the Von Frey hair and Hargreaves’ methods. Western-blotting, qPCR and immunofluorescence were used to detect the cell signaling pathway. RAW264.7 macrophages and RSC96 Schwann cells were cultured for in vitro evaluation.ResultsIntraplantar administration of anti-NGF mAbs suppressed the expression of phosphorylated transforming growth factor-β-activated kinase 1 (TAK1) in the dorsal root ganglion (DRG) and sciatic nerve. Intraplantar administration of a TAK1 inhibitor attenuated CCI-induced neuropathic pain and suppressed the expression of phosphorylated mitogen-activated protein kinases (MAPKs) in the DRG and sciatic nerve. Perisciatic nerve administration of levo-corydalmine (l-CDL) on the operated side obviously attenuated CCI-induced neuropathic pain and suppressed the expression of mNGF and proNGF. In addition, l-CDL-induced antinociception was reversed by intraplantar administration of NGF. Further results indicated that l-CDL-induced suppression of phosphorylated TAK1, MAPKs, and p65 and expression of the proinflammatory cytokines TNF-α and IL-1β in the DRG and sciatic nerve were all abolished by NGF. In addition, in vitro experiments indicated that l-CDL suppressed the secretion of NGF and proNGF in RAW264.7 macrophages and RSC96 Schwann cells, which was abolished by AP-1 and CREB agonists, respectively.ConclusionsThis study showed NGF inhibition suppressed TAK1 in the periphery to attenuate CCI-induced neuropathic pain through inhibition of downstream MAPK and p65 signaling. The natural compound l-CDL inhibited NGF secretion by macrophages and Schwann cells and downstream TAK1-MAPK/NF-κB signaling in the periphery to attenuate CCI-induced neuropathic pain.C3K7z76gapiovQmzs8ZFSVVideo abstractGraphical abstractProposed mechanisms underlying the effect of l-CDL in periphery of CCI rats. In CCI rats, macropahages and Schwann cells could secret NGF to act on the receptors in the periphery to activate TAK1-MAPK/NF-κB axis and promote the release of proinflammatory cytokines, including TNF-α and IL-1β to promote neuropathic pain. l-CDL decreased the secretion of NGF through inhibiting AP-1 and CREB respectively in RAW264.7 and RSC96 Schwann cells to attenuate CCI-induced neuropathic pain by inhibiting the TAK1-p38 MAPK/NF-κB signaling pathway.

TAB3 upregulates PIM1 expression by directly activating the TAK1-STAT3 complex to promote colorectal cancer growth

Transforming growth factor-β-activated kinase 1 (TAK1)-binding protein 3 (TAB3) and the proviral integration site for Moloney murine leukaemia virus 1 (PIM1) are implicated in cancer development. In this study, we investigated the relationship between TAB3 and PIM1 in colorectal cancer (CRC) and determined the potential role and molecular mechanism of TAB3 in PIM1-mediated CRC growth. We found that TAB3 and PIM1 expression levels were positively correlated in CRC tissues. The knockdown of TAB3 significantly decreased PIM1 expression and inhibited CRC proliferation in vitro and in vivo. The upregulation of PIM1 rescued the decreased cell proliferation induced by TAB3 knockdown, whereas PIM1 knockdown decreased TAB3-enhanced CRC proliferation. Additionally, TAB3 regulates PIM1 expression through the STAT3 signalling pathway and confirmed a positive correlation between TAB3 and phosphorylated-STAT3 expression in CRC tissues. Patients with high expression of TAB3 and phosphorylated-STAT3 had the worst prognosis. Mechanistically, TAB3 regulates PIM1 expression by promoting STAT3 phosphorylation and activation through the formation of the TAB3-TAK1-STAT3 complex. Overall, a novel CRC regulatory circuit involving the TAB3-TAK1-STAT3 complex and PIM1 was identified, the dysfunction of which may contribute to CRC tumorigenesis.

USP15 potentiates NF-κB activation by differentially stabilizing TAB2 and TAB3.

Tumor necrosis factor α (TNFα)- and interleukin 1β (IL-1β)-induced nuclear factor-κB (NF-κB) activation play key roles in inflammation, immunity, and cancer development. Here, we identified one of the deubiquitinating enzymes (DUBs), ubiquitin-specific protease 15 (USP15), as a positive regulator in both TNFα- and IL-1β-induced NF-κB activation. Overexpression of USP15 potentiated TNFα- or IL-1β-triggered NF-κB activation and downstream gene transcription, whereas knockdown of USP15 had opposite effects. Mechanistically, upon TNFα stimulation, USP15 showed an enhanced interaction with transforming growth factor-β activated kinase-1 (TAK1)-TAK1 binding protein (TAB) complex to inhibit the proteolysis of TAB2/3 by different pathways. Apart from deubiquitination dependently inducing cleavage of lysine 48-linked TAB2 ubiquitination, USP15 also DUB independently inhibited lysosome-associated TAB2 degradation, thus enhanced TAB2 stabilization. For TAB3, USP15 inhibited NBR1-mediated selective autophagic TAB3 degradation independent of its deubiquitinating activity. Together, our results reveal a novel USP15-mediated mechanism through which efficient NF-κB activation is achieved by differentially maintaining the TAB2/3 stability.

TAK1 deficiency attenuates cisplatin-induced acute kidney injury.

Cisplatin can cause acute kidney injury (AKI), but the molecular mechanisms are not well understood. The objective of the present study was to examine the role of transforming growth factor-β-activated kinase-1 (TAK1) in the pathogenesis of cisplatin-induced AKI. Wild-type mice and proximal tubule TAK1-deficient mice were treated with vehicle or cisplatin. Compared with wild-type control mice, proximal tubule TAK1-deficient mice had less severe kidney dysfunction, tubular damage, and apoptosis after cisplatin-induced AKI. Furthermore, conditional disruption of TAK1 in proximal tubular epithelial cells reduced caspase-3 activation, proinflammatory molecule expression, and JNK phosphorylation in the kidney in cisplatin-induced AKI. Taken together, cisplatin activates TAK1-JNK signaling pathway to promote tubular epithelial cell apoptosis and inflammation in cisplatin-induced AKI. Targeting TAK1 could be a novel therapeutic strategy against cisplatin-induced AKI.

Early appearance of key transcription factors influence the spatiotemporal development of the human inner ear

Expression patterns of transcription factors leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5), transforming growth factor-β-activated kinase-1 (TAK1), SRY (sex-determining region Y)-box 2 (SOX2), and GATA binding protein 3 (GATA3) in the developing human fetal inner ear were studied between the gestation weeks 9 and 12. Further development of cochlear apex between gestational weeks 11 and 16 (GW11 and GW16) was examined using transmission electron microscopy. LGR5 was evident in the apical poles of the sensory epithelium of the cochlear duct and the vestibular end organs at GW11. Immunostaining was limited to hair cells of the organ of Corti by GW12. TAK1 was immune positive in inner hair cells of the organ of Corti by GW12 and colocalized with p75 neurotrophic receptor expression. Expression for SOX2 was confined primarily to the supporting cells of utricle at the earliest stage examined at GW9. Intense expression for GATA3 was presented in the cochlear sensory epithelium and spiral ganglia at GW9. Expression of GATA3 was present along the midline of both the utricle and saccule in the zone corresponding to the striolar reversal zone where the hair cell phenotype switches from type I to type II. The spatiotemporal gradient of the development of the organ of Corti was also evident with the apex of the cochlea forming by GW16. It seems that highly specific staining patterns of several transcriptions factors are critical in guiding the genesis of the inner ear over development. Our findings suggest that the spatiotemporal gradient in cochlear development extends at least until gestational week 16.

Dietary resveratrol supplementation inhibits heat stress-induced high-activated innate immunity and inflammatory response in spleen of yellow-feather broilers

The aim of this study was to investigate the effect of dietary resveratrol supplementation on innate immunity and inflammatory responses in the spleen of yellow-feather broilers under heat stress. A total of 288 yellow-feather broilers of 28-day-old were randomly assigned to 3 treatment groups with 6 replicates. A thermo-neutral group (TN) (24 ± 2°C) received a basal diet and another 2 heat-stressed groups (37 ± 2°C for 8 h/D and 24 ± 2°C for the remaining time) were fed the basal diet (HT) or basal diet with 500 mg/kg resveratrol (HT+Res) for 14 consecutive days. The results showed that heat stress decreased (P < 0.05) the growth index of thymus, spleen, and bursa of Fabricius, reduced (P < 0.05) the levels of complement C3 and C4 in serum. Heat stress also caused activation of inflammatory immune responses evidenced by increased (P < 0.05) the mRNA abundance of HSP (heat shock protein) 70, toll-like receptor (TLR)1, TLR4, TLR5, myeloid differentiation factor-88 (MyD88), nucleotide-binding oligomerization domain 1 (NOD1), Dectin-1, transforming growth factor-β-activated kinase 1 (TAK1), interleukin (IL)-1, IL-4, IL-6, and tumor necrosis factor (TNF)-α, but decreased the mRNA abundance of interferon (IFN)-γ, activated nuclear factor kappa B (NF-κB), mitogen-activated protein kinases (MAPK), and phosphoinositide-3 kinases-protein kinase B (PI3K/AKT) signaling pathways. Dietary supplementation with resveratrol improved (P < 0.05) the growth index of thymus, spleen and bursa Fabricius, and increased (P < 0.05) the serum level of complement C3 under heat stress. In addition, resveratrol reduced (P < 0.05) the mRNA abundance of HSP70, TLR4, TLR5, NOD1, Dectin-1, and TAK1, and inhibited the NF-κB, MAPK and PI3K/AKT signaling pathway via down-regulated the phosphorylation of p65, extracellular signal-regulated kinases 1/2, c-Jun N-terminal protein kinase and AKT, as well as decreased the inflammatory cytokines expression, including IL-1, IL-4, IL-6, and TNF-α in the spleen under heat stress. Collectively, dietary resveratrol could have beneficial effects to regulate innate immunity and inflammatory response, via inhibiting the activation of NF-κB, MAPK, and PI3K/AKT signaling pathways induced by heat stress in the spleen.