TAB1: an activator of the TAK1 MAPKKK in TGF-beta signal transduction

The Bacterial Outer Membrane Vesicle-Cloaked Immunostimulatory Nanoplatform Reinvigorates T Cell Function and Reprograms Tumor Immunity

Bacterial outer membrane vesicles (OMVs) represent powerful immunoadjuvant nanocarriers with the capacity to reprogram the tumor microenvironment (TME) and activate immune responses. Here, we investigate a nanotherapeutic platform integrating immunostimulatory cytosine-phosphate-guanine oligodeoxynucleotides (CpG-ODNs, hereafter termed CpG) into mesoporous silica nanoparticles cloaked with OMVs (CpG@MSN-PEG/PEI@OMVs) for cancer immunotherapy. Systemic administration of these nanohybrids facilitates precise tumor targeting, induces antitumor cytokines such as IFNγ, and suppresses immunosuppressive cytokine TGF-β, reshaping the TME. Additionally, CpG@MSN-PEG/PEI@OMVs promote M1 macrophage polarization, dendritic cell maturation, and the generation of durable tumor-specific immune memory, resulting in pronounced tumor regression with minimal systemic toxicity. The platform demonstrates efficacy against metastatic and solid tumor models including 4T1 breast and MC38 colorectal cancers. Transcriptomic analyses reveal that CpG@MSN-PEG/PEI@OMVs enhance mitochondrial oxidative phosphorylation in T cells within tumor-draining lymph nodes, mitigating T cell exhaustion and restoring metabolic fitness. These results support the potential of CpG@MSN-PEG/PEI@OMVs as a modular nanoplatform to modulate innate and adaptive immunity in cancer immunotherapy.

RGMb drives macrophage infiltration to aggravate kidney disease

The importance of macrophages in kidney diseases has been well established; however, the mechanisms underlying the infiltration of macrophages into injured kidneys are not well understood. RGMb is a member of the repulsive guidance molecule (RGM) family. RGMb can be expressed on the cell surface but a large portion of RGMb is localized intracellularly. Among various immune cell types, macrophages express the highest levels of RGMb, but the biological functions of RGMb in macrophages remain largely unknown. We find that RGMb promoted macrophage migration in vitro and that in vivo, RGMb enhanced infiltration of macrophages into injured kidneys and aggravated kidney inflammation and injury in mice. Mechanistically, RGMb bound to TAB1 inside the cell and facilitated the interaction between TRAF6 ubiquitin ligase and TAB1, thereby promoting TRAF6-mediated K63-linked polyubiquitination and phosphorylation of TAK1, followed by increased αTAT1 phosphorylation and α-tubulin acetylation. The resulting changes in the cytoskeleton promoted macrophage migration in vitro and in vivo. Deletion of Rgmb in macrophages markedly reduced TAK1 phosphorylation, αTAT1 phosphorylation, and α-tubulin acetylation and attenuated macrophage infiltration, renal inflammation, tubular injury, and interstitial fibrosis during kidney injury. Our results suggest that macrophage RGMb promotes kidney disease by increasing macrophage infiltration via the TRAF6-TAB1-TAK1/αTAT1/α-tubulin cascade.

An examination of the LPS-TLR4 immune response through the analysis of molecular structures and protein-protein interactions

The LPS-TLR4 immune response is a critical mechanism in the body's defense against Gram-negative bacterial infections, yet its dysregulation can lead to severe inflammatory diseases. Lipopolysaccharide (LPS), a pivotal pathogen-associated molecular pattern (PAMP) on the surface of gram-negative bacteria, is recognized by Toll-like receptor 4 (TLR4), initiating a complex cascade of immune responses. This review delves into the intricate molecular structures and protein-protein interactions that underpin the LPS-TLR4 signaling pathway, offering a comprehensive analysis of both extracellular recognition and intracellular signal transduction. We explore the roles of key molecules such as LBP, CD14, MD-2, and TLR4 in the initial recognition of LPS, followed by the downstream signaling pathways mediated by MyD88-dependent and MyD88-independent mechanisms. The MyD88-dependent pathway primarily activates NF-κB and AP-1, leading to macrophage M1 polarization and the release of pro-inflammatory cytokines, while the MyD88-independent pathway triggers IRF activation and type-I interferon production. By elucidating the structural basis and functional interactions of these signaling molecules, this review not only enhances our understanding of the LPS-TLR4 immune response but also highlights its implications in both infectious and non-infectious diseases. Our findings underscore the potential of targeting this pathway for therapeutic interventions, offering new avenues for the treatment of inflammatory and immune-related disorders.

TAK1 at the crossroads of multiple regulated cell death pathways: from molecular mechanisms to human diseases

Regulated cell death (RCD), the form of cell death that can be genetically controlled by multiple signaling pathways, plays an important role in organogenesis, tissue remodeling, and maintenance of organism homeostasis and is closely associated with various human diseases. Transforming growth factor‐beta‐activated kinase 1 (TAK1) is a member of the serine/threonine protein kinase family, which can respond to different internal and external stimuli and participate in inflammatory and immune responses. Emerging evidence suggests that TAK1 is an important regulator at the crossroad of multiple RCD pathways, including apoptosis, necroptosis, pyroptosis, and PANoptosis. The regulation of TAK1 affects disease progression through multiple signaling pathways, and therapeutic strategies targeting TAK1 have been proposed for inflammatory diseases, central nervous system diseases, and cancers. In this review, we provide an overview of the downstream signaling pathways regulated by TAK1 and its binding proteins. Their critical regulatory roles in different forms of cell death are also summarized. In addition, we discuss the potential of targeting TAK1 in the treatment of human diseases, with a specific focus on neurological disorders and cancer.

Targeting TAK1: Evolution of inhibitors, challenges, and future directions

The increasing incidence of inflammatory and malignant diseases signifies the need to develop first-in-class drugs with novel mechanisms of action. In this respect, the transforming growth factor (TGF)-β-activated kinase 1 (TAK1), an essential part of several signaling pathways, is considered relevant and promising. This manuscript provides a brief overview of the signal transduction orchestrated by TAK1 within these pathways, followed by an in-depth and thorough analysis of the chemical matter demonstrated to inhibit this kinase. Special attention is given to the selectivity profiling of inhibitors, as well as to the outcomes of their biological characterization. Because published TAK1 inhibitors differ significantly in their kinome selectivity, active-site binding, and biological activity, we hope that this review will allow a judicial estimation of their quality and usefulness for TAK1-addressing assays. Our thoughts on the perspectives and possible developments of the field are also provided to assist scientists who are involved in the design and development of TAK1-targeting modulators.

Bibliometric and visualized analysis on global trends and hotspots of TAK1 in regulated cell death: 1999 to 2024

BACKGROUND

Regulated cell death (RCD) is a genetically controlled form of cell death that plays an important role in organogenesis, tissue remodeling, and pathogenesis of cancers. Transforming growth factor-beta-activation kinase 1 (TAK1) is a member of the serine/threonine protein kinase family, which can respond to internal and external stimuli and participate in inflammatory responses through multiple signaling pathways and cellular processes. In the last two decades, the regulatory roles of TAK1 at the crossroads of multiple RCD pathways, including apoptosis, necroptosis, pyroptosis, and PANoptosis were revealed by 801 articles retrieved from the Web of Science Core Collection database. To analyze global research trends and hotspots concerning the role of TAK1 in RCD, the bibliometric and visualized analysis were applied in the current study.

METHODS

The data for this bibliometrics study were retrieved from the Web of Science Core Collection database. The search formula was (TS=(Apoptosis) OR TS=(pyroptosis) OR TS=(Necroptosis) OR TS=(PANoptosis) OR TS=(Autophagy) OR TS=(Ferroptosis) OR TS=(cuproptosis)) AND ((TS=(TAK1)) OR TS=(MAP3K7)). The co-occurrence and co-cited analysis on basic bibliometric parameters were conducted by VOSviewer. The dual-map overlay of journals, citation bursts, keyword timelines, and keyword bursts were analyzed by CiteSpace.

RESULTS

A total of 801 articles from 46 countries have been included in the analysis. The number of publications demonstrates a consistent increase from 1999 to 2024. The primary research institutions driving this field are Osaka University Notably, the Journal of Biological Chemistry stands out as the most popular journal in this domain. These publications collectively involve contributions from 4663 authors, with Jun Tsuji emerging as a prolific author. Jun Tsuji also gains the highest co-citation frequency. Emerging research hotspots are encapsulated by keywords, including apoptosis, NF-κB, inflammation, autophagy, and TNFα.

CONCLUSION

This is the first bibliometric and visualized study to analyze the global trends and hotspots of TAK1 in RCD. Based on the analysis of 801 articles, the results provide a retrospective and comprehensive visualized view of the research hotspots and frontiers of TAK1 at the crossroads of multiple RCD signaling pathways and propose ideas for guiding their future investigations in molecular mechanisms and therapeutic strategies in this field.

The inhibitory effect of swine TAB1 on the replication of pseudorabies virus

TAK1-binding protein 1 (TAB1) assembles with TAK1 through its C-terminal domain, leading to the self-phosphorylation and activation of TAK1, which plays an important role in the activation of NF-κB and MAPK signaling pathway. Pseudorabies virus (PRV) is the pathogen of Pseudorabies (PR), which belongs to the Alphaherpesvirus subfamily and causes serious economic losses to the global pig industry. However, the impact of swine TAB1 (sTAB1) on PRV infection has not been reported. In this study, evidence from virus DNA copies, virus titer and western blotting confirmed that sTAB1 could inhibit PRV replication and knockout of sTAB1 by CRISPR-Cas9 gene editing system could promote PRV replication. Further mechanistic studies by real-time PCR and luciferase reporter gene assay demonstrated that sTAB1 could enhance the production of inflammatory factors and chemokines, IFN-β transcription level and IFN-β promoter activity after PRV infection. In summary, we clarify the underlying mechanism of sTAB1 in inhibiting PRV replication for the first time, which provides a new idea for preventing PRV infection and lays a foundation for PRV vaccine development.

Modulation of extrinsic apoptotic pathway by intracellular glycosylation

The importance of post-translational modifications (PTMs), particularly O-GlcNAcylation, of cytoplasmic proteins in apoptosis has been neglected for quite a while. Modification of cytoplasmic proteins by a single N-acetylglucosamine sugar is a dynamic and reversible PTM exhibiting properties more like phosphorylation than classical O- and N-linked glycosylation. Due to the sparse information existing, we have only limited understanding of how GlcNAcylation affects cell death. Deciphering the role of GlcNAcylation in cell fate may provide further understanding of cell fate decisions. This review focus on the modulation of extrinsic apoptotic pathway via GlcNAcylation carried out by O-GlcNAc transferase (OGT) or by other bacterial effector proteins.

Structure, unique biological properties, and mechanisms of action of transforming growth factor β

Transforming growth factor β (TGF-β) is a ubiquitous molecule that is extremely conserved structurally and plays a systemic role in human organism. TGF-β is a homodimeric molecule consisting of two subunits joined through a disulphide bond. In mammals, three genes code for TGF-β1, TGF-β2, and TGF-β3 isoforms of this cytokine with a dominating expression of TGF-β1. Virtually, all normal cells contain TGF-β and its specific receptors. Considering the exceptional role of fine balance played by the TGF-β in anumber of physiological and pathological processes in human body, this cytokine may be proposed for use in medicine as an immunosuppressant in transplantology, wound healing and bone repair. TGFb itself is an important target in oncology. Strategies for blocking members of TGF-β signaling pathway as therapeutic targets have been considered. In this review, signalling mechanisms of TGF-β1 action are addressed, and their role in physiology and pathology with main focus on carcinogenesis are described.

The TAK1/JNK axis participates in adaptive immunity by promoting lymphocyte activation in Nile tilapia

The transforming growth factor beta-activated kinase 1 (TAK1)/c-Jun N-terminal kinase (JNK) axis is an essential MAPK upstream mediator and regulates immune signaling pathways. However, whether the TAK1/JNK axis harnesses the strength in regulation of signal transduction in early vertebrate adaptive immunity is unclear. In this study, by modeling on Nile tilapia (Oreochromis niloticus), we investigated the potential regulatory function of TAK1/JNK axis on lymphocyte-mediated adaptive immune response. Both OnTAK1 and OnJNK exhibited highly conserved sequences and structures relative to their counterparts in other vertebrates. Their mRNA was widely expressed in the immune-associated tissues, while phosphorylation levels in splenic lymphocytes were significantly enhanced on the 4th day post-infection by Edwardsiella piscicida. In addition, OnTAK1 and OnJNK were significantly up-regulated in transcriptional level after activation of lymphocytes in vitro by phorbol 12-myristate 13-acetate plus ionomycin (P + I) or PHA, accompanied by a predominant increase in phosphorylation level. More importantly, inhibition of OnTAK1 activity by specific inhibitor NG25 led to a significant decrease in the phosphorylation level of OnJNK. Furthermore, blocking the activity of OnJNK with specific inhibitor SP600125 resulted in a marked reduction in the expression of T-cell activation markers including IFN-γ, CD122, IL-2, and CD44 during PHA-induced T-cell activation. In summary, these findings indicated that the conserved TAK1/JNK axis in Nile tilapia was involved in adaptive immune responses by regulating the activation of lymphocytes. This study enriched the current knowledge of adaptive immunity in teleost and provided a new perspective for understanding the regulatory mechanism of fish immunity.

TAK1 in Vascular Signaling: "Friend or Foe"?

The maintenance of normal vascular function and homeostasis is largely dependent on the signaling mechanisms that occur within and between cells of the vasculature. TGF-β-activated kinase 1 (TAK1), a multifaceted signaling molecule, has been shown to play critical roles in various tissue types. Although the precise function of TAK1 in the vasculature remains largely unknown, emerging evidence suggests its potential involvement in both physiological and pathological processes. A comprehensive search strategy was employed to identify relevant studies, PubMed, Web of Science, and other relevant databases were systematically searched using keywords related to TAK1, TABs and MAP3K7.In this review, we discussed the role of TAK1 in vascular signaling, with a focus on its function, activation, and related signaling pathways. Specifically, we highlight the TA1-TABs complex is a key factor, regulating vascular smooth muscle cells (VSMCs) and endothelial cells (ECs) involved in the processes of inflammation, vascular proliferation and angiogenesis. This mini review aims to elucidate the evidence supporting TAK1 signaling in the vasculature, in order to better comprehend its beneficial and potential harmful effects upon TAK1 activation in vascular tissue.

Construction and analysis of a joint diagnostic model of machine learning for cryptorchidism based on single-cell sequencing

BACKGROUND

Cryptorchidism is a condition in which one or both of a baby's testicles do not fully descend into the bottom of the scrotum. Newborns with cryptorchidism are at increased risk of developing infertility later in life. The aim of this study was to develop a novel diagnostic model for cryptorchidism and to identify new biomarkers associated with cryptorchidism.

METHODS

The study data were obtained from RNA sequencing data of cryptorchid patients from Nantong University Hospital and the Gene Expression Omnibus (GEO) database. Differential expression analysis was used to obtain differentially expressed genes (DEGs) between the control and cryptorchid groups. These DEGs were analyzed for their functions by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment using GSEA software. Random Forest algorithm was used to screen central genes based on these DEGs. Neuralnet software package was used to develop artificial neural network models. Based on clinical data, receiver operating characteristic (ROC) was used to validate the models. Single-cell sequencing analysis was used for the pathogenesis of cryptorchidism.

RESULTS

We obtained a total of 525 important DEGs related to cryptorchidism, which are mainly associated with biological functions such as supramolecular complexes and microtubule cytoskeleton. Random forest approach screening obtained eight hub genes. A neural network based on the hub genes showed a 100% success rate of the model. Finally, single-cell sequencing analysis validated the hub genes.

CONCLUSION

We developed a novel diagnostic model for cryptorchidism using artificial neural networks and validated its utility as an effective diagnostic tool.

Molecular characterization, expression and functional analysis of TAK1, TAB1 and TAB2 in Nile tilapia (Oreochromis niloticus)

The MAPK pathway is the common intersection of signal transduction pathways such as inflammation, differentiation and proliferation and plays an important role in the process of antiviral immunity. Streptococcus agalactiae will have a great impact on tilapia aquaculture, so it is necessary to study the immune response mechanism of tilapia to S. agalactiae. In this study, we isolated the cDNA sequences of TAK1, TAB1 and TAB2 from Nile tilapia (Oreochromis niloticus). The TAK1 gene was 3492 bp in length, contained an open reading frame (ORF) of 1809 bp and encoded a polypeptide of 602 amino acids. The cDNA sequence of the TAB1 gene was 4001 bp, and its ORF was 1491 bp, which encoded 497 amino acids. The cDNA sequence of the TAB2 gene was 4792 bp, and its ORF was 2217 bp, encoding 738 amino acids. TAK1 has an S_TKc domain and a coiled coil structure; the TAB1 protein structure contains a PP2C_SIG domain and a conserved PYVDXA/TXF sequence model; and TAB2 contains a CUE domain, a coiled coil domain and a Znf_RBZ domain. Homology analysis showed that TAK1 and TAB1 had the highest homology with Neolamprologus brichardi, and TAB2 had the highest homology with Simochromis diagramma (98.28 %). In the phylogenetic tree, TAK1, TAB1 and TAB2 formed a large branch with other scleractinian fishes. The tissue expression analysis showed that the expression of TAK1, TAB1 and TAB2 was highest in the muscle. The expression of TAK1, TAB1 and TAB2 was significantly induced in most of the tested tissues after stimulation with LPS, Poly I:C and S. agalactiae. The subcellular localization results showed that TAK1 was located in the cytoplasm, and TAB1 and TAB2 had certain distributions in the cytoplasm and nucleus. Coimmunoprecipitation (Co-IP) results showed that TRAF6 did not interact with the TAK1 protein but interacted with TAB2, while TAB1 did not interact with P38γ but interacted with TAK1. There was also an interaction between TAK1 and TAB2.

TGFβ1-driven SMAD2/3 phosphorylation and myofibroblast emergence are fully dependent on the TGFβ1 pre-activation of MAPKs and controlled by maternal leucine zipper kinase

Following wounding, endogenously secreted TGFβs drive resident and bone marrow-derived cells to convert into α-smooth actin (SMA)-rich, contractile myofibroblasts. The TGFβ effect is initiated by the phosphorylation of SMADs 2 and 3 (SMAD2/3). This event has been referred to as the canonical response to TGFβ. TGFβ also elicits other responses viewed as parallel events not directly connected to the SMAD activation, and thus referred to as noncanonical. A recognized response is the phosphorylation of the -activated kinase (TAK1/MAP3K), an upstream component of the mitogen-activated protein kinase (MAPK) cascade. We have now examined the relationship between these two effects of TGFβ1 at their earliest stages. The bulk of the studies were carried out with primary fibroblasts derived from the human cornea. The results' widespread relevance was confirmed in critical experiments with dermal-, and Tenon's capsule-derived fibroblasts. Cells were treated with kinase inhibitors or targeting siRNAs followed by induction by 2 ng/ml TGFβ1, and/or 10 ng/ml TNF-α. Cells were collected after 1 to 30 min for Western blot analysis and assayed for the accumulation of phosphorylated TAK1, ASK1, JNK1/2, p38, HPS27, MELK, SMAD2/3, and GAPDH. The effect of the kinase inhibitors on α-SMA expression and α-SMA stress fiber organization was also tested. For the immediate response to TGFβ1 we found that a) activation of the MAPK pathway was completed within 1 min after the addition of TGFβ1; b) phosphorylation of JNK1/2 was fully dependent on TAK1 and ASK1 activity, c) phosphorylation of MELK was fully dependent on JNK1/2 activity; d) phosphorylation of ASK1 depends on MELK activity, indicating the existence of an ASK1-MELK positive activation feedback loop; e) phosphorylation of SMAD2/3 started only after a 5 min period and reached a nadir after 10-15 min, f) the latter phosphorylation was fully blocked by inhibition of TAK1, ASK1, JNK1/2, and MELK, and siRNA-driven MELK downregulation; g) the inhibitors equally blocked the α-SMA protein expression, stress fiber development, and cell morphology changes at 72 h. These results demonstrate that the activation of the canonical pathway is fully subordinate to the activity of the MAPK pathway, challenging the concept of canonical and noncanonical TGFβ pathways and that SMAD2/3 activation is mediated by MELK, a kinase not previously associated with rapid pharmacological responses.

Smyd3 negatively regulates the anti-viral pathway by promoting TAK1 degradation in teleost fish

IMPORTANCE

In this study, we have found that the existence of Smyd3 promoted the replication of SCRV. Additionally, we report that Smyd3 negatively regulates the NF-κB and IRF3 signaling pathway by facilitating the degradation of TAK1 in fish. Our findings suggest that Smyd3 interacts with TAK1. Further investigations have revealed that Smyd3 specifically mediates K48-linked ubiquitination of TAK1 and enhances TAK1 degradation, resulting in a significant inhibition of the NF-κB and IRF3 signaling pathway. These results not only contribute to the advancement of fish anti-viral immunity but also provide new evidence for understanding the mechanism of TAK1 in mammals.

TAK1 is an essential kinase for STING trafficking

The translocation of stimulator of interferon genes (STING) from the endoplasmic reticulum (ER) to the ER-Golgi intermediate compartment (ERGIC) enables its activation. However, the mechanism underlying the regulation of STING exit from the ER remains elusive. Here, we found that STING induces the activation of transforming growth factor beta-activated kinase 1 (TAK1) prior to STING trafficking in a TAK1 binding protein 1 (TAB1)-dependent manner. Intriguingly, activated TAK1 directly mediates STING phosphorylation on serine 355, which facilitates its interaction with STING ER exit protein (STEEP) and thereby promotes its oligomerization and translocation to the ERGIC for subsequent activation. Importantly, activation of TAK1 by monophosphoryl lipid A, a TLR4 agonist, boosts cGAMP-induced antitumor immunity dependent on STING phosphorylation in a mouse allograft tumor model. Taken together, TAK1 was identified as a checkpoint for STING activation by promoting its trafficking, providing a basis for combinatory tumor immunotherapy and intervention in STING-related diseases.

Small molecule activators of TAK1 promotes its activity-dependent ubiquitination and TRAIL-mediated tumor cell death

TAK1 is a key modulator of both NF-κB signaling and RIPK1. In TNF signaling pathway, activation of TAK1 directly mediates the phosphorylation of IKK complex and RIPK1. In a search for small molecule activators of RIPK1-mediated necroptosis, we found R406/R788, two small molecule analogs that could promote sustained activation of TAK1. Treatment with R406 sensitized cells to TNF-mediated necroptosis and RIPK1-dependent apoptosis by promoting sustained RIPK1 activation. Using click chemistry and multiple biochemical binding assays, we showed that treatment with R406 promotes the activation of TAK1 by directly binding to TAK1, independent of its original target Syk kinase. Treatment with R406 promoted the ubiquitination of TAK1 and the interaction of activated TAK1 with ubiquitinated RIPK1. Finally, we showed that R406/R788 could promote the cancer-killing activities of TRAIL in vitro and in mouse models. Our studies demonstrate the possibility of developing small molecule TAK1 activators to potentiate the effect of TRAIL as anticancer therapies.

BMP signaling in the development and regeneration of tooth roots: from mechanisms to applications

Short root anomaly (SRA), along with caries, periodontitis, and trauma, can cause tooth loss, affecting the physical and mental health of patients. Dental implants have become widely utilized for tooth restoration; however, they exhibit certain limitations compared to natural tooth roots. Tissue engineering-mediated root regeneration offers a strategy to sustain a tooth with a physiologically more natural function by regenerating the bioengineered tooth root (bio-root) based on the bionic principle. While the process of tooth root development has been reported in previous studies, the specific molecular mechanisms remain unclear. The Bone Morphogenetic Proteins (BMPs) family is an essential factor regulating cellular activities and is involved in almost all tissue development. Recent studies have focused on exploring the mechanism of BMP signaling in tooth root development by using transgenic animal models and developing better tissue engineering strategies for bio-root regeneration. This article reviews the unique roles of BMP signaling in tooth root development and regeneration.

Notoginsenoside R1 protects against myocardial ischemia/reperfusion injury in mice via suppressing TAK1-JNK/p38 signaling

Previous studies show that notoginsenoside R1 (NG-R1), a novel saponin isolated from Panax notoginseng, protects kidney, intestine, lung, brain and heart from ischemia-reperfusion injury. In this study we investigated the cardioprotective mechanisms of NG-R1 in myocardial ischemia/reperfusion (MI/R) injury in vivo and in vitro. MI/R injury was induced in mice by occluding the left anterior descending coronary artery for 30 min followed by 4 h reperfusion. The mice were treated with NG-R1 (25 mg/kg, i.p.) every 2 h for 3 times starting 30 min prior to ischemic surgery. We showed that NG-R1 administration significantly decreased the myocardial infarction area, alleviated myocardial cell damage and improved cardiac function in MI/R mice. In murine neonatal cardiomyocytes (CMs) subjected to hypoxia/reoxygenation (H/R) in vitro, pretreatment with NG-R1 (25 μM) significantly inhibited apoptosis. We revealed that NG-R1 suppressed the phosphorylation of transforming growth factor β-activated protein kinase 1 (TAK1), JNK and p38 in vivo and in vitro. Pretreatment with JNK agonist anisomycin or p38 agonist P79350 partially abolished the protective effects of NG-R1 in vivo and in vitro. Knockdown of TAK1 greatly ameliorated H/R-induced apoptosis of CMs, and NG-R1 pretreatment did not provide further protection in TAK1-silenced CMs under H/R injury. Overexpression of TAK1 abolished the anti-apoptotic effect of NG-R1 and diminished the inhibition of NG-R1 on JNK/p38 signaling in MI/R mice as well as in H/R-treated CMs. Collectively, NG-R1 alleviates MI/R injury by suppressing the activity of TAK1, subsequently inhibiting JNK/p38 signaling and attenuating cardiomyocyte apoptosis.

CARD19, a Novel Regulator of the TAK1/NF-κB Pathway in Self-Reactive B Cells

The caspase recruitment domain family member (CARD)11-Bcl10-Malt1 signalosome controls TGF-β-activated kinase 1 (TAK1) activation and regulates BCR-induced NF-κB activation. In this study, we discovered that CARD19 interacted with TAK1 and inhibited TAB2-mediated TAK1 ubiquitination and activation. Although CARD19 deficiency in mice did not affect B cell development, it enhanced clonal deletion, receptor editing, and anergy of self-reactive B cells, and it reduced autoantibody production. Mechanistically, CARD19 deficiency increased BCR/TAK1-mediated NF-κB activation, leading to increased expression of transcription factors Egr2/3, as well as the E3 ubiquitin ligases c-Cbl/Cbl-b, which are known inducers of B cell tolerance in self-reactive B cells. RNA sequencing analysis revealed that although CARD19 deficiency did not affect the overall Ag-induced gene expression in naive B cells, it suppressed BCR signaling and increased hyporesponsiveness of self-reactive B cells. As a result, CARD19 deficiency prevented Bm12-induced experimental systemic lupus erythematosus. In summary, CARD19 negatively regulates BCR/TAK1-induced NF-κB activation and its deficiency increases Egr2/3 and c-Cbl/Cbl-b expression in self-reactive B cells, thereby enhancing B cell tolerance.

Suppression of triple-negative breast cancer aggressiveness by LGALS3BP via inhibition of the TNF-α-TAK1-MMP9 axis

Transforming growth factor-β-activated kinase 1 (TAK1), which is highly expressed and aberrantly activated in triple-negative breast cancer (TNBC), plays a pivotal role in metastasis and progression. This makes it a potential therapeutic target for TNBC. Previously, we reported lectin galactoside-binding soluble 3 binding protein (LGALS3BP) as a negative regulator of TAK1 signaling in the inflammatory response and inflammation-associated cancer progression. However, the role of LGALS3BP and its molecular interaction with TAK1 in TNBC remain unclear. This study aimed to investigate the function and underlying mechanism of action of LGALS3BP in TNBC progression and determine the therapeutic potential of nanoparticle-mediated delivery of LGALS3BP in TNBC. We found that LGALS3BP overexpression suppressed the overall aggressive phenotype of TNBC cells in vitro and in vivo. LGALS3BP inhibited TNF-α-mediated gene expression of matrix metalloproteinase 9 (MMP9), which encodes a protein crucial for lung metastasis in TNBC patients. Mechanistically, LGALS3BP suppressed TNF-α-mediated activation of TAK1, a key kinase linking TNF-α stimulation and MMP9 expression in TNBC. Nanoparticle-mediated delivery enabled tumor-specific targeting and inhibited TAK1 phosphorylation and MMP9 expression in tumor tissues, suppressing primary tumor growth and lung metastasis in vivo. Our findings reveal a novel role of LGALS3BP in TNBC progression and demonstrate the therapeutic potential of nanoparticle-mediated delivery of LGALS3BP in TNBC.

Emerging role of TAK1 in the regulation of skeletal muscle mass

Maintenance of skeletal muscle mass and strength throughout life is crucial for heathy living and longevity. Several signaling pathways have been implicated in the regulation of skeletal muscle mass in adults. TGF-β-activated kinase 1 (TAK1) is a key protein, which coordinates the activation of multiple signaling pathways. Recently, it was discovered that TAK1 is essential for the maintenance of skeletal muscle mass and myofiber hypertrophy following mechanical overload. Forced activation of TAK1 in skeletal muscle causes hypertrophy and attenuates denervation-induced muscle atrophy. TAK1-mediated signaling in skeletal muscle promotes protein synthesis, redox homeostasis, mitochondrial health, and integrity of neuromuscular junctions. In this article, we have reviewed the role and potential mechanisms through which TAK1 regulates skeletal muscle mass and growth. We have also proposed future areas of research that could be instrumental in exploring TAK1 as therapeutic target for improving muscle mass in various catabolic conditions and diseases.

RNF207 exacerbates pathological cardiac hypertrophy via post-translational modification of TAB1

AIMS

The heart undergoes pathological remodelling, featured by the hypertrophic growth of cardiomyocytes and increased cardiac fibrosis, under biomechanical stress such as haemodynamic overload. Ring Finger Protein 207 (RNF207) is an E3 ubiquitin ligase that is predominantly expressed in the heart, but its function remains elusive. In this study, we aimed to explore the role of RNF207 in the development of pathological cardiac hypertrophy and dysfunction.

METHODS AND RESULTS

Transverse aortic constriction (TAC) surgery was performed on mice to induce cardiac hypertrophy. Cardiac function and remodelling were evaluated by echocardiography, histological assessment, and molecular analyses. Our data indicated that RNF207 overexpression (OE) exacerbated cardiac hypertrophy, fibrosis, and systolic dysfunction. In contrast, TAC-induced cardiac remodelling was profoundly blunted in RNF207 knockdown (KD) hearts. In line with the in vivo findings, RNF207 OE augmented, whereas RNF207 KD alleviated, phenylephrine-induced cardiomyocyte hypertrophy in vitro. Mechanistically, we demonstrated that RNF207 elicited detrimental effects by promoting K63-linked ubiquitination of TAK1-binding protein 1 (TAB1), which triggered the autophosphorylation of transforming growth factor-β activated kinase 1 (TAK1) and the activation of downstream p38 and c-Jun N-terminal kinase (JNK)1/2 signalling pathways. In the TAB1-KD cardiomyocytes, RNF207-OE-induced cell hypertrophy was significantly attenuated, indicating that RNF207-induced hypertrophy is, at least in part, TAB1-dependent.

CONCLUSIONS

This study demonstrates that RNF207 exacerbates pressure overload-induced cardiac hypertrophy and dysfunction via post-translational modification of TAB1.

Hsa_circ_0021727 (circ-CD44) promotes ESCC progression by targeting miR-23b-5p to activate the TAB1/NFκB pathway

Esophageal squamous cell carcinoma (ESCC) is characterized by high morbidity and mortality. Circular RNAs (circRNAs) play an important role in tumor progression. We discovered an aberrantly expressed circRNA (hsa_circ_0021727) in patients with ESCC. However, the mechanism of action of hsa_circ_0021727 in tumors is unclear. The present study aimed to investigate the biological role of hsa_circ_0021727 and its mechanism in ESCC progression. We screened for the expression of hsa_circ_0021727 in ESCC patients. Patients with ESCC with high expression of hsa_circ_0021727 had shorter survival than those with low expression. Hsa_circ_0021727 promoted the proliferation, invasion, and migration of ESCC cells. However, miR-23b-5p inhibited this ability of hsa_circ_0021727. MiR-23b-5p acts by targeting TAK1-binding protein 1 (TAB1). Upregulation of TAB1 can activate the nuclear factor kappa B (NFκB) pathway. Hsa_circ_0021727 promoted ESCC progression by activating TAB1/NFκB pathway by sponging miR-23b-5p. In addition, in vivo experiments also confirmed that hsa_circ_0021727 could promote the proliferation, invasion, and migration of ESCC cells. In short, hsa_circ_0021727 promotes ESCC progression by targeting miR-23b-5p to activate the TAB1/NFκB pathway. These findings might provide potential targets to treat ESCC.

The WNT/Ca2+ pathway promotes atrial natriuretic peptide secretion by activating protein kinase C/transforming growth factor-β activated kinase 1/activating transcription factor 2 signaling in isolated beating rat atria

WNT signaling plays an important role in cardiac development, but abnormal activity is often associated with cardiac hypertrophy, myocardial infarction, remodeling, and heart failure. The effect of WNT signaling on regulation of atrial natriuretic peptide (ANP) secretion is unclear. Therefore, the purpose of this study was to investigate the effect of Wnt agonist 1 (Wnta1) on ANP secretion and mechanical dynamics in beating rat atria. Wnta1 treatment significantly increased atrial ANP secretion and pulse pressure; these effects were blocked by U73122, an antagonist of phospholipase C. U73122 also abolished the effects of Wnta1-mediated upregulation of protein kinase C (PKC) β and γ expression, and the PKC antagonist Go 6983 eliminated Wnta1-induced secretion of ANP. In addition, Wnta1 upregulated levels of phospho-transforming growth factor-β activated kinase 1 (p-TAK1), TAK1 banding 1 (TAB1) and phospho-activating transcription factor 2 (p-ATF2); these effects were blocked by both U73122 and Go 6983. Wnta1-induced ATF2 was abrogated by inhibition of TAK1. Furthermore, Wnta1 upregulated the expression of T cell factor (TCF) 3, TCF4, and lymphoid enhancer factor 1 (LEF1), and these effects were blocked by U73122 and Go 6983. Tak1 inhibition abolished the Wnta1-induced expression of TCF3, TCF4, and LEF1 and Wnta1-mediated ANP secretion and changes in mechanical dynamics. These results suggest that Wnta1 increased the secretion of ANP and mechanical dynamics in beating rat atria by activation of PKC-TAK1-ATF2-TCF3/LEF1 and TCF4/LEF1 signaling mainly via the WNT/Ca2+ pathway. It is also suggested that WNT-ANP signaling is implicated in cardiac physiology and pathophysiology.

The Role of TAK1 in RANKL-Induced Osteoclastogenesis

Bone remodelling is generally a dynamic process orchestrated by bone-resorbing osteoclasts and bone-forming osteoblasts. Osteoclasts are the only cell type capable of bone resorption to maintain bone homeostasis in the human body. However, excessive osteoclastogenesis can lead to osteolytic diseases. The receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL) has been widely considered to be an important modulator of osteoclastogenesis thereby participating in the pathogenesis of osteolytic diseases. Transforming growth factor β-activated kinase 1 (TAK1), a member of the mitogen-activated protein kinase kinase kinase family, is an important intracellular molecule that regulates multiple signalling pathways, such as NF-κB and mitogen-activated protein kinase to mediate multiple physiological processes, including cell survival, inflammation, and tumourigenesis. Furthermore, increasing evidence has demonstrated that TAK1 is intimately involved in RANKL-induced osteoclastogenesis. Moreover, several detailed mechanisms by which TAK1 regulates RANKL-induced osteoclastogenesis have been clarified, and some potential approaches targeting TAK1 for the treatment of osteolytic diseases have emerged. In this review, we discuss how TAK1 functions in RANKL-mediated signalling pathways and highlight the significant role of TAK1 in RANKL-induced osteoclastogenesis. In addition, we discuss the potential clinical implications of TAK1 inhibitors for the treatment of osteolytic diseases.

Tripartite Motif 38 Attenuates Cardiac Fibrosis after Myocardial Infarction by Suppressing TAK1 Activation via TAB2/3 Degradation

The role of tripartite motif (TRIM) 38, a ubiquitin E3 ligase regulating various pathophysiological processes, in cardiac fibrosis remains unclear. Here, a model of angiotensin II and myocardial infarction (MI)-induced fibrosis was established to explore its role in cardiac fibrosis and its underlying mechanisms. Cardiac fibrosis in the mouse MI model was mitigated by TRIM38 overexpression, but aggravated by its depletion. Consistently, in vitro overexpression or knockdown of TRIM38 ameliorated or aggravated the proliferation and secretion of cardiac fibroblasts (CFs) exposed to fibrotic stimulation, respectively. Mechanistically, TRIM38 suppressed cardiac fibrosis progression by attenuating TAK1/MAPK signaling. Inhibiting TAK1/MAPK signaling with a pharmacological inhibitor greatly reversed the effects of TRIM38 knockdown on CF secretion. Specifically, TRIM38 interacted with and “targeted” TAB2 and TAB3 for degradation, subsequently inhibiting TAK1 phosphorylation and negatively regulating MAPK signaling. These findings can help develop therapeutic strategies to treat and prevent cardiac fibrosis.

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TRIM38 expression is negatively correlated with cardiac fibrosis progression

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TRIM38 ameliorates the proliferation and secretion of CFs post fibrotic stimulation

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TRIM38 overexpression attenuates cardiac fibrosis progression in MI mice

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TRIM38 inhibits the TAK1/MAPK pathway by targeting the degradation of TAB2 and TAB3

GCN5-mediated regulation of pathological cardiac hypertrophy via activation of the TAK1-JNK/p38 signaling pathway

Pathological cardiac hypertrophy is a process of abnormal remodeling of cardiomyocytes in response to pressure overload or other stress stimuli, resulting in myocardial injury, which is a major risk factor for heart failure, leading to increased morbidity and mortality. General control nonrepressed protein 5 (GCN5)/lysine acetyltransferase 2 A, a member of the histone acetyltransferase and lysine acetyltransferase families, regulates a variety of physiological and pathological events. However, the function of GCN5 in pathological cardiac hypertrophy remains unclear. This study aimed to explore the role of GCN5 in the development of pathological cardiac hypertrophy. GCN5 expression was increased in isolated neonatal rat cardiomyocytes (NRCMs) and mouse hearts of a hypertrophic mouse model. GCN5 overexpression aggravated the cardiac hypertrophy triggered by transverse aortic constriction surgery. In contrast, inhibition of GCN5 impairs the development of pathological cardiac hypertrophy. Similar results were obtained upon stimulation of NRCMs (having GCN5 overexpressed or knocked down) with phenylephrine. Mechanistically, our results indicate that GCN5 exacerbates cardiac hypertrophy via excessive activation of the transforming growth factor β-activated kinase 1 (TAK1)-c-Jun N-terminal kinase (JNK)/p38 signaling pathway. Using a TAK1-specific inhibitor in rescue experiments confirmed that the activation of TAK1 is essential for GCN5-mediated cardiac hypertrophy. In summary, the current study elucidated the role of GCN5 in promotion of cardiac hypertrophy, thereby implying it to be a potential target for treatment.

BMP-2 Long-Term Stimulation of Human Pre-Osteoblasts Induces Osteogenic Differentiation and Promotes Transdifferentiation and Bone Remodeling Processes

Bone morphogenic protein (BMP-) 2 plays an important role in the regeneration of bone defects by promoting osteogenic differentiation. However, several animal studies have reported adverse side effects of BMP-2, including osteoclast activation, induction of peroxisome proliferator- activated receptor gamma (PPARG)expression, and inflammation. High BMP-2 concentrations are thought to be responsible for these side effects. For this reason, primary pre-osteoblasts were exposed to lower BMP-2 concentrations (1 and 2 µg/mL). Long-term exposure (up to 28 days) was performed to investigate whether this stimulation protocol may promote osteogenic differentiation without causing the side effects mentioned above. The results showed that BMP-2 treatment for 14 or 28 days resulted in increased osteogenesis, through an increase in runt-related transcription factor 2, osterix, alkaline phosphatase, and integrin-binding sialoprotein expression. However, an increase in tumor necrosis factor alpha and receptor activator of nuclear factor kappa-Β ligand protein levels was observed after BMP-2 exposure, indicating also an increased potential for osteoclast activation by osteoblasts. Additionally, morphological changes like intracellular, filled vacuoles could be detected. Enhanced PPARG and perilipin 1 mRNA transcripts and lipid droplets indicated an induced adipogenic differentiation. Overall, the data demonstrate that long-term BMP-2 exposure promotes not only osteogenic differentiation but also adipogenesis and regulates mediators involved in osteoclast activation in vitro.

The miR-23a/27a/24-2 cluster promotes postoperative progression of early-stage non-small cell lung cancer

Even with optimal surgery, many early-stage non-small cell lung cancer (NSCLC) patients die of recurrence. Unfortunately, there are no precise predictors for postoperative recurrence in early-stage NSCLC, and the recurrence mechanism is still unclear. In this study, we found that simultaneous overexpression of all miRNAs in the miR-23a/27a/24-2 cluster was closely associated with postoperative recurrence, β-catenin upregulation and promoter methylation of p16 and CDH13 in early-stage NSCLC patients. In addition, in vitro and in vivo experiments show that overexpression or inhibition of all miRNAs in the miR-23a/27a/24-2 cluster significantly stimulated or inhibited NSCLC cell stemness, tumorigenicity and metastasis. Furthermore, we demonstrated that the miR-23a/27a/24-2 cluster miRNAs activated Wnt/β-catenin signaling by targeting their suppressors and stimulated promoter methylation-induced silencing of p16 and CDH13 by affecting DNA methylation-related genes expression. Our findings suggest that simultaneous high expression of all miRNAs in the miR-23a/27a/24-2 cluster represents a new biomarker for predicting postoperative recurrence in early-stage NSCLC. The miR-23a/27a/24-2 cluster miRNAs stimulate early-stage NSCLC progression through simultaneously stimulating Wnt/β-catenin signaling, and promoter methylation-induced tumor suppressor genes silencing. In addition, simultaneous inhibition of all miRNAs in the miR-23a/27a/24-2 cluster may be a useful strategy for treatment of early-stage NSCLC recurrence.

TAB2 deficiency induces dilated cardiomyopathy by promoting RIPK1-dependent apoptosis and necroptosis

Mutations in TGF-β-activated kinase 1 binding protein 2 (TAB2) have been implicated in the pathogenesis of dilated cardiomyopathy and/or congenital heart disease in humans, but the underlying mechanisms are currently unknown. Here, we identified an indispensable role for TAB2 in regulating myocardial homeostasis and remodeling by suppressing receptor-interacting protein kinase 1 (RIPK1) activation and RIPK1-dependent apoptosis and necroptosis. Cardiomyocyte-specific deletion of Tab2 in mice triggered dilated cardiomyopathy with massive apoptotic and necroptotic cell death. Moreover, Tab2-deficient mice were also predisposed to myocardial injury and adverse remodeling after pathological stress. In cardiomyocytes, deletion of TAB2 but not its close homolog TAB3 promoted TNF-α-induced apoptosis and necroptosis, which was rescued by forced activation of TAK1 or inhibition of RIPK1 kinase activity. Mechanistically, TAB2 critically mediates RIPK1 phosphorylation at Ser321 via a TAK1-dependent mechanism, which prevents RIPK1 kinase activation and the formation of RIPK1-FADD-caspase-8 apoptotic complex or RIPK1-RIPK3 necroptotic complex. Strikingly, genetic inactivation of RIPK1 with Ripk1-K45A knockin effectively rescued cardiac remodeling and dysfunction in Tab2-deficient mice. Together, these data demonstrated that TAB2 is a key regulator of myocardial homeostasis and remodeling by suppressing RIPK1-dependent apoptosis and necroptosis. Our results also suggest that targeting RIPK1-mediated cell death signaling may represent a promising therapeutic strategy for TAB2 deficiency-induced dilated cardiomyopathy.

TAK1 of blunt snout bream promotes NF-κB activation via interaction with TAB1 in response to pathogenic bacteria

Transforming growth factor-β activated kinase-1 (TAK1) is an important upstream signaling molecules involved in the NF-κB signaling pathway. TAK1 interacts with TAB1 to form the TAK1-TAB1 complex, which elicits NF-κB activation through a series of cascade reactions in mammals. However, the function of TAK1 in blunt snout bream (Megalobrama amblycephala ( maTak1) and the effects of their interaction between TAK1 and TAB1 on the NF-κB activation still remains largely unknown. In the present study, maTak1 was cloned and characterized successfully based on transcriptome data. Its open reading frame is composed of 1626 nucleotides and the predicted maTAK1 protein contains 541 amino acids, which includes an N-terminal Serine/Threonine protein kinases (S/TKc) and a C-terminal coiled-coil region. Phylogenetic analysis showed that maTAK1 were clustered with those of other teleosts. MaTak1 displayed ubiquitous transcriptional expression in all the examined tissues of healthy blunt snout bream but with varied expression levels. And maTrak1 expression was dramatically enhanced in different tissues and MAF cells after LPS stimulation and A. hydrophila challenge. The result from subcellular localization analysis indicated that both maTAK1 and maTAB1 were cytoplasmic protein. The activity of NF-κB promoter could not be induced by overexpression of maTak1 or maTab1 alone, however, it could be enhanced by co-expression of maTak1 and maTab1. Co-immunoprecipitation and subcellular co-localization assay revealed that maTAK1 can combine with maTAB1 directly. The transcriptional expression level of pro-inflammatory cytokines (IL-1β, IL-6 and IL-8) increased distinctly after the overexpression of maTak1 and maTab1. Taken together, the data obtained in this study demonstrated that the direct interaction between maTAK1 and maTAB1 might play a pivotal role in mediating host innate immune response to pathogen invasion by the production of pro-inflammatory cytokines via NF-κB signaling pathway, which might lay a solid foundation for the establishment of novel therapeutic approach to combat bacterial infection in fish.

TAK1: A Molecular Link Between Liver Inflammation, Fibrosis, Steatosis, and Carcinogenesis

Chronic insult and persistent injury can cause liver inflammation, fibrosis, and carcinogenesis; it can also be associated with metabolic disorders. Identification of critical molecules that link the process of inflammation and carcinogenesis will provide prospective therapeutic targets for liver diseases. Rapid advancements in gene engineering technology have allowed the elucidation of the underlying mechanism of transformation, from inflammation and metabolic disorders to carcinogenesis. Transforming growth factor-β-activated kinase 1 (TAK1) is an upstream intracellular protein kinase of nuclear factor kappa-B (NF-κB) and c-Jun N-terminal kinases, which are activated by numerous cytokines, growth factors, and microbial products. In this study, we highlighted the functional roles of TAK1 and its interaction with transforming growth factor-β, WNT, AMP-activated protein kinase, and NF-κB signaling pathways in liver inflammation, steatosis, fibrosis, and carcinogenesis based on previously published articles.

TRIM26 positively regulates the inflammatory immune response through K11-linked ubiquitination of TAB1

Protein ubiquitination plays an important role in the regulation of TGF-β-activated kinase 1 (TAK1)-mediated NF-κB activation. It is well established that TAK1 activation is tightly regulated with its binding partners, TAK1-binding proteins (TAB1-3). However, the tight regulation of TAK1 activation remains elusive. Here, using Trim26-knockout mice and Trim26-transgenic mice, we found that TRIM26 acts as a positive regulator of TAK1 activation by ubiquitinating its binding partner TAB1. Knockout of Trim26 inhibited TAK1 activation and downstream kinases activation, thus decreasing the induction of proinflammatory cytokines following LPS, TNF-α, and IL-1β stimulation. Mechanistically, TRIM26 catalyzes the K11-linked polyubiquitination of TAB1 at Lys294, Lys319, and Lys335 to enhance the activation of TAK1 and subsequent NF-κB and MAPK signaling. Consequently, Trim26 deficiency protects mice from LPS-induced septic shock in vivo. Moreover, Trim26 deficiency attenuates the severity of dextran sodium sulfate (DSS)-induced colitis. Thus, these finding provides a novel insight into how TAK1 activation is regulated through TRIM26-mediated ubiquitination of TAB1 and reveals the new function of TRIM26 in the regulation of the inflammatory innate immune response.

The inflammatory signalling mediator TAK1 mediates lymphocyte recruitment to lipopolysaccharide-activated murine mesenchymal stem cells through interleukin-6

As a response to pro-inflammatory signals mesenchymal stem cells (MSCs) secrete agents and factors leading to lymphocyte recruitment, counteracting inflammation, and stimulating immunosuppression. On a molecular level, the signalling mediator TGF-β-activated kinase 1 (TAK1) is activated by many pro-inflammatory signals, plays a critical role in inflammation and regulates innate and adaptive immune responses as well. While the role of TAK1 as a signalling factor promoting inflammation is well documented, we also considered a role for TAK1 in anti-inflammatory actions exerted by activated MSCs. We, therefore, investigated the capacity of lipopolysaccharide (LPS)-treated murine MSCs with lentivirally modulated TAK1 expression levels to recruit lymphocytes. TAK1 downregulated by lentiviral vectors expressing TAK1 shRNA in murine MSCs interfered with the capacity of murine MSCs to chemoattract lymphocytes, indeed. Analysing a pool of 84 secreted factors we found that among 26 secreted cytokines/factors TAK1 regulated expression of one cytokine in LPS-activated murine MSCs in particular: interleukin-6 (IL-6). IL-6 in LPS-treated MSCs was responsible for lymphocyte recruitment as substantiated by neutralizing antibodies. Our studies, therefore, suggest that in LPS-treated murine MSCs the inflammatory signalling mediator TAK1 may exert anti-inflammatory properties via IL-6.

The Roles of Pseudophosphatases in Disease

The pseudophosphatases, atypical members of the protein tyrosine phosphatase family, have emerged as bona fide signaling regulators within the past two decades. Their roles as regulators have led to a renaissance of the pseudophosphatase and pseudoenyme fields, catapulting interest from a mere curiosity to intriguing and relevant proteins to investigate. Pseudophosphatases make up approximately fourteen percent of the phosphatase family, and are conserved throughout evolution. Pseudophosphatases, along with pseudokinases, are important players in physiology and pathophysiology. These atypical members of the protein tyrosine phosphatase and protein tyrosine kinase superfamily, respectively, are rendered catalytically inactive through mutations within their catalytic active signature motif and/or other important domains required for catalysis. This new interest in the pursuit of the relevant functions of these proteins has resulted in an elucidation of their roles in signaling cascades and diseases. There is a rapid accumulation of knowledge of diseases linked to their dysregulation, such as neuropathies and various cancers. This review analyzes the involvement of pseudophosphatases in diseases, highlighting the function of various role(s) of pseudophosphatases involvement in pathologies, and thus providing a platform to strongly consider them as key therapeutic drug targets.

MicroRNA-211 regulates the expression of TAB1 and inhibits the NF-κB signaling pathway in lipopolysaccharide-induced endometritis

Endometritis is a common postpartum inflammatory disease that endangers the reproductive health of humans and animals. Emerging evidence shows that microRNA is a new type of therapeutic molecule that plays a vital role in many diseases; however, its mechanism of action in lipopolysaccharide (LPS)-induced endometritis is still unclear. This study aims to investigate the regulatory role of miR-211 in the innate immune response involved in endometritis, and to evaluate its potential therapeutic value. Here, we found that the expression of miR-211 in bovine endometrial epithelial cells (bEECs) stimulated by lipopolysaccharide (LPS) was significantly reduced. Importantly, overexpression of miR-211 can significantly reduce the production of pro-inflammatory cytokines (IL-1β , IL-6 and TNF-α). In addition, we proved that TAB1 is the target gene of miR-211. MiR-211 inhibits TAB1 protein expression by binding to the 3'-UTR of TAB1 mRNA. Subsequently, we verified that the overexpression of miR-211 inhibited the activation of NF-κB p65 by targeting the TAB1-mediated pathway. Therefore, miR-211 has anti-inflammatory effects and mediates the negative regulation of the NF-κB signaling pathway in LPS-induced endometritis by targeting TAB1.

Discovery of 2,4-1H-Imidazole Carboxamides as Potent and Selective TAK1 Inhibitors

Herein we report the discovery of 2,4-1H-imidazole carboxamides as novel, biochemically potent, and kinome selective inhibitors of transforming growth factor β-activated kinase 1 (TAK1). The target was subjected to a DNA-encoded chemical library (DECL) screen. After hit analysis a cluster of compounds was identified, which was based on a central pyrrole-2,4-1H-dicarboxamide scaffold, showing remarkable kinome selectivity. A scaffold-hop to the corresponding imidazole resulted in increased biochemical potency. Next, X-ray crystallography revealed a distinct binding mode compared to other TAK1 inhibitors. A benzylamide was found in a perpendicular orientation with respect to the core hinge-binding imidazole. Additionally, an unusual amide flip was observed in the kinase hinge region. Using structure-based drug design (SBDD), key substitutions at the pyrrolidine amide and the glycine resulted in a significant increase in biochemical potency.

Fragmentation of Small-Cell Lung Cancer Regulatory States in Heterotypic Microenvironments

Small-cell lung cancers derive from pulmonary neuroendocrine cells, which have stem-like properties to reprogram into other cell types upon lung injury. It is difficult to uncouple transcriptional plasticity of these transformed cells from genetic changes that evolve in primary tumors or secondary metastases. Profiling of single cells is also problematic if the required sample dissociation activates injury-like signaling and reprogramming. Here we defined cell-state heterogeneities in situ through laser capture microdissection-based 10-cell transcriptomics coupled with stochastic-profiling fluctuation analysis. In labeled cells from a small-cell lung cancer mouse model initiated by neuroendocrine deletion of Rb1-Trp53, variations in transcript abundance revealed cell-to-cell differences in regulatory state in vitro and in vivo. Fluctuating transcripts in spheroid culture were partly shared among Rb1-Trp53-null models, and heterogeneities increased considerably when cells were delivered intravenously to colonize the liver. Colonization of immunocompromised animals drove a fractional appearance of alveolar type II-like markers and poised cells for paracrine stimulation from immune cells and hepatocytes. Immunocompetency further exaggerated the fragmentation of tumor states in the liver, yielding mixed stromal signatures evident in bulk sequencing from autochthonous tumors and metastases. Dozens of transcript heterogeneities recurred irrespective of biological context; their mapped orthologs brought together observations of murine and human small-cell lung cancer. Candidate heterogeneities recurrent in the liver also stratified primary human tumors into discrete groups not readily explained by molecular subtype but with prognostic relevance. These data suggest that heterotypic interactions in the liver and lung are an accelerant for intratumor heterogeneity in small-cell lung cancer. SIGNIFICANCE: These findings demonstrate that the single-cell regulatory heterogeneity of small-cell lung cancer becomes increasingly elaborate in the liver, a common metastatic site for the disease.See related articles by Singh and colleagues, p. 1840 and Sutcliffe and colleagues, p. 1868.

Interactions between Salmonella and host macrophages - Dissecting NF-κB signaling pathway responses

Salmonella not only invades host cells, but also replicates intracellularly to cause a range of diseases, including gastroenteritis and systemic infections such as typhoid fever. The body's first line of defense against pathogens is the innate immune response system that can protect against Salmonella invasion and replication. Nuclear factor κB (NF-κB) is an important transcriptional regulator that plays an important role in host inflammatory responses to pathogens. Both the canonical and non-canonical NF-κB signaling pathways are activated by Salmonella in many different ways through its virulence factors, leading to the release of inflammatory factors and the activation of inflammatory responses in mammalian hosts. Equally, Salmonella, as an enteropathogen, has accordingly evolved strategies to disturb NF-κB activation, such as secreting some effector proteins by type III secretion systems as well as inducing host cells to express NF-κB pathway inhibitors, allowing it to colonize and persistently infect the hosts. This review focuses on how Salmonella activates NF-κB signaling pathway and the strategies used by Salmonella to interfere with the NF-κB pathway activation.

Tumor suppressor DRD2 facilitates M1 macrophages and restricts NF-κB signaling to trigger pyroptosis in breast cancer

Rationale: Breast cancer (BrCa) is the most common cancer worldwide, and the 5-year relative survival rate has declined in patients diagnosed at stage IV. Advanced BrCa is considered as incurable, which still lack effective treatment strategies. Identifying and characterizing new tumor suppression genes is important to establish effective prognostic biomarkers or therapeutic targets for late-stage BrCa.

Methods: RNA-seq was applied in BrCa tissues and normal breast tissues. Through analyzing differentially expressed genes, DRD2 was selected for further analysis. And expression and promoter methylation status of DRD2 were also determined. DRD2 functions were analyzed by various cell biology assays in vitro. Subcutaneous tumor model was used to explore DRD2 effects in vivo. A co-cultivated system was constructed to investigate interactions of DRD2 and macrophages in vitro. WB, IHC, IF, TUNEL, qRT-PCR, Co-IP, Antibody Array, and Mass Spectrum analysis were further applied to determine the detailed mechanism.

Results: In BrCa, DRD2 was found to be downregulated due to promoter methylation. Higher expression of DRD2 positively correlated with longer survival times especially in HER2-positive patients. DRD2 also promoted BrCa cells sensitivity to Paclitaxel. Ectopic expression of DRD2 significantly inhibited BrCa tumorigenesis. DRD2 also induced apoptosis as well as necroptosis in vitro and in vivo. DRD2 restricted NF-κB signaling pathway activation through interacting with β-arrestin2, DDX5 and eEF1A2. Interestingly, DRD2 also regulated microenvironment as it facilitated M1 polarization of macrophages, and triggered GSDME-executed pyroptosis.

Conclusion: Collectively, this study novelly manifests the role of DRD2 in suppressing BrCa tumorigenesis, predicting prognosis and treatment response. And this study further reveals the critical role of DRD2 in educating M1 macrophages, restricting NF-κB signaling pathway and triggering different processes of programmed cell death in BrCa. Taking together, those findings represent a predictive and therapeutic target for BrCa.

TAK1-TABs Complex: A Central Signalosome in Inflammatory Responses

Transforming growth factor-β (TGF-β)-activated kinase 1 (TAK1) is a member of the MAPK kinase kinase (MAPKKK) family and has been implicated in the regulation of a wide range of physiological and pathological processes. TAK1 functions through assembling with its binding partners TAK1-binding proteins (TAB1, TAB2, and TAB3) and can be activated by a variety of stimuli such as tumor necrosis factor α (TNFα), interleukin-1β (IL-1β), and toll-like receptor ligands, and they play essential roles in the activation of NF-κB and MAPKs. Numerous studies have demonstrated that post-translational modifications play important roles in properly controlling the activity, stability, and assembly of TAK1-TABs complex according to the indicated cellular environment. This review focuses on the recent advances in TAK1-TABs-mediated signaling and the regulations of TAK1-TABs complex by post-translational modifications.

TXNIP Regulates Natural Killer Cell-Mediated Innate Immunity by Inhibiting IFN-γ Production during Bacterial Infection

The function of natural killer (NK) cell-derived interferon-γ (IFN-γ) expands to remove pathogens by increasing the ability of innate immune cells. Here, we identified the critical role of thioredoxin-interacting protein (TXNIP) in the production of IFN-γ in NK cells during bacterial infection. TXNIP inhibited the production of IFN-γ and the activation of transforming growth factor β-activated kinase 1 (TAK1) activity in primary mouse and human NK cells. TXNIP directly interacted with TAK1 and inhibited TAK1 activity by interfering with the complex formation between TAK1 and TAK1 binding protein 1 (TAB1). Txnip^−/− (KO) NK cells enhanced the activation of macrophages by inducing IFN-γ production during Pam3CSK4 stimulation or Staphylococcus aureus (S. aureus) infection and contributed to expedite the bacterial clearance. Our findings suggest that NK cell-derived IFN-γ is critical for host defense and that TXNIP plays an important role as an inhibitor of NK cell-mediated macrophage activation by inhibiting the production of IFN-γ during bacterial infection.

Partners in crime: POPX2 phosphatase and its interacting proteins in cancer

Protein phosphorylation and dephosphorylation govern intracellular signal transduction and cellular functions. Kinases and phosphatases are involved in the regulation and development of many diseases such as Alzheimer’s, diabetes, and cancer. While the functions and roles of many kinases, as well as their substrates, are well understood, phosphatases are comparatively less well studied. Recent studies have shown that rather than acting on fewer and more distinct substrates like the kinases, phosphatases can recognize specific phosphorylation sites on many different proteins, making the study of phosphatases and their substrates challenging. One approach to understand the biological functions of phosphatases is through understanding their protein–protein interaction network. POPX2 (Partner of PIX 2; also known as PPM1F or CaMKP) is a serine/threonine phosphatase that belongs to the PP2C family. It has been implicated in cancer cell motility and invasiveness. This review aims to summarize the different binding partners of POPX2 phosphatase and explore the various functions of POPX2 through its interactome in the cell. In particular, we focus on the impact of POPX2 on cancer progression. Acting via its different substrates and interacting proteins, POPX2’s involvement in metastasis is multifaceted and varied according to the stages of metastasis.

CD83, a Novel MAPK Signaling Pathway Interactor, Determines Ovarian Cancer Cell Fate

Ovarian cancer is a leading cause of death from gynecologic malignancies worldwide. Although CD83 is widely described as a solid marker for mature dendritic cells, emerging pieces of evidence indicate the expression of membrane protein CD83 by various tumor cells, including ovarian cancer cells. However, the potential role of CD83 in ovarian cancer cell properties and development remains absolutely unknown. By using human CD83 stable overexpression and knockdown sublines of several ovarian cancer cells, we observed that CD83 advanced the growth proliferation, colony formation ability, spheroid formation, and in vivo tumorigenicity of ovarian cancer cells; surprisingly, CD83 limited their migration and invasion potentials. Positive regulation of proliferation/stemness factors (e.g., cyclin-CDKs and KIT/CD44) but negative regulation of matrix metallopeptidases (e.g., MMP1 and 7) by CD83 were revealed by the integrated analysis of transcriptome and proteome. Furthermore, immunoprecipitation-mass spectrometry (IP-MS) and co-immunoprecipitation (Co-IP) first identified the association of CD83 with MAP3K7 (also known as TAK1) and MAP3K7-binding protein TAB1 on the cell membrane. Moreover, CD83 functions through the activation of MAP3K7-MEK1/2-ERK1/2 cascades to further regulate downstream FOXO1/p21/CDK2/CCNB1 and STAT3/DKK1 signaling pathways, thus activating proliferation and spheroid formation of ovarian cancer cells, respectively. Collectively, our findings define a CD83-MAPK pathway in the regulation of proliferation and stemness in ovarian cancer cells, with potential therapeutic applications in blocking their progression.

Regeneration of Damaged Tendon-Bone Junctions (Entheses)-TAK1 as a Potential Node Factor

Musculoskeletal dysfunctions are highly prevalent due to increasing life expectancy. Consequently, novel solutions to optimize treatment of patients are required. The current major research focus is to develop innovative concepts for single tissues. However, interest is also emerging to generate applications for tissue transitions where highly divergent properties need to work together, as in bone-cartilage or bone-tendon transitions. Finding medical solutions for dysfunctions of such tissue transitions presents an added challenge, both in research and in clinics. This review aims to provide an overview of the anatomical structure of healthy adult entheses and their development during embryogenesis. Subsequently, important scientific progress in restoration of damaged entheses is presented. With respect to enthesis dysfunction, the review further focuses on inflammation. Although molecular, cellular and tissue mechanisms during inflammation are well understood, tissue regeneration in context of inflammation still presents an unmet clinical need and goes along with unresolved biological questions. Furthermore, this review gives particular attention to the potential role of a signaling mediator protein, transforming growth factor beta-activated kinase-1 (TAK1), which is at the node of regenerative and inflammatory signaling and is one example for a less regarded aspect and potential important link between tissue regeneration and inflammation.

A mouse model for functional dissection of TAB1 O-GlcNAcylation

Background: O-GlcNAcylation is a posttranslational modification associated with various physiological and pathophysiological processes including diabetes, cancer, neurodegeneration and inflammation. However, the biological mechanisms underlying the role of specific O-GlcNAc sites and their link to phenotypes remain largely unexplored due to lack of suitable in vivo models. TGF-β activated kinase-1 binding protein-1 (TAB1) is a scaffolding protein required for TGF-β activated kinase-1 (TAK1) mediated signalling. A single O-GlcNAc site has been identified on human TAB1 that modulates TAK1-mediated cytokine release in cells.

Methods: Here, we report the generation of the Tab1 ^S393A mouse model using a constitutive knock-in strategy. The Tab1 ^S393A mice carry a Ser393Ala (S393A) mutation that leads to loss of O-GlcNAcylation site on TAB1.

Results: We did not observe any obvious phenotype in Tab1 ^S393A mice. Loss of O-GlcNAcylation on TAB1 has no consequences on TAB1 protein level or on TAB1-TAK1 interaction.

Conclusions: The homozygous Tab1 ^S393A mice are viable and develop with no obvious abnormalities, providing a powerful tool to further investigate the role of O-GlcNAc on TAB1 in the inflammatory response in the context of a whole organism.

Therapeutic effect of omega-3 fatty acids on T cell-mediated autoimmune diseases

The present study was to demonstrate that the G protein coupled receptors serve as targets for the treatment of autoimmune disease such as rheumatoid arthritis and multiple sclerosis. Rats received pristane at the base of the tail. Affected joints were counted daily. The T cell mediated autoimmune diseases such as pristine-induced arthritis (PIA) and autoimmune encephalomyelitis (EAE) in a rat model were profoundly ameliorated by treatment with the specific G protein couple receptors 120 (GPR120) stimuli omega-3 fatty acids (ω-3 FAs). Our study further revealed that the activation of GPR120 by ω-3 FAs can result in a decrease of phosphorylated transforming growth factor-β activated kinase 1 (TAK1), and further inhibit the downstream IKKβ/I-κB pathway and the terminal NF-κB activation which serves as a mediator of T cell activation. ω-3 Fatty acids exhibited an inhibitory effect on TAK1 by enhancing the association of β-arrestin2 and TAK1 binding protein 1 (TAB1), thus the disassociation of TAB1 from the TAB1/TAK1 complex renders a limited effect on β-arrestin2 signaling as an innate immunity regulation. GPR120 is a functional receptor of ω-3 fatty acids in T cell-mediated autoimmune disease compared with its effect on innate immunity.