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TBK1 is a serine-threonine protein kinase that has been linked to a number of diseases including amyotrophic lateral sclerosis and frontotemporal dementia. Reproducible research on TBK1 has been hampered by the lack of well characterized antibodies. In this study, we characterized 11 commercial antibodies for TBK1 for use in immunoblot, immunofluorescence and immunoprecipitation, using an isogeneic knock-out cell line as a control. We identify antibodies that appear specific for all three applications but invite the readers to interpret the present findings based on their own scientific expertise and use this report as a guide to select the most appropriate antibody for their specific needs.

Metabolic rewiring is required for cancer cells to survive in harsh microenvironments and is considered to be a hallmark of cancer. Specific metabolic adaptations are required for a tumor to become invasive and metastatic. Cell division and metabolism are inherently interconnected, and several cell cycle modulators directly regulate metabolism. Here, we report that TBK1, which is a noncanonical IKK kinase with known roles in cell cycle regulation and TLR signaling, affects cellular metabolism in cancer cells. While TBK1 is reported to be overexpressed in several cancers and its enhanced protein level correlates with poor prognosis, the underlying molecular mechanism involved in the tumor-promoting role of TBK1 is not fully understood. In this study, we show a novel role of TBK1 in regulating cancer cell metabolism using combined metabolomics, transcriptomics, and pharmacological approaches. We find that TBK1 mediates the regulation of nucleotide and energy metabolism through aldo-keto reductase B10 (AKRB10) and thymidine phosphorylase (TYMP) genes, suggesting that this TBK1-mediated metabolic rewiring contributes to its oncogenic function. In addition, we find that TBK1 inhibitors can act synergistically with AKRB10 and TYMP inhibitors to reduce cell viability. These findings raise the possibility that combining these inhibitors might be beneficial in combating cancers that show elevated levels of TBK1.

TAX1BP1 is a selective macroautophagy/autophagy receptor that inhibits NFKB and RIGI-like receptor (RLR) signaling to prevent excessive inflammation and maintain homeostasis. Selective autophagy receptors such as SQSTM1/p62 and OPTN are phosphorylated by the kinase TBK1 to stimulate their selective autophagy function. However, it is unknown if TAX1BP1 is regulated by TBK1 or other kinases under basal conditions or during RNA virus infection. Here, we found that TBK1 and IKBKE/IKKi function redundantly to phosphorylate TAX1BP1 and regulate its autophagic turnover through canonical macroautophagy. TAX1BP1 phosphorylation promotes its localization to lysosomes, resulting in its degradation. Additionally, we found that during vesicular stomatitis virus infection, TAX1BP1 is targeted to lysosomes in an ATG8-family protein-independent manner. Furthermore, TAX1BP1 plays a critical role in the clearance of MAVS aggregates, and phosphorylation of TAX1BP1 controls its MAVS aggrephagy function. Together, our data support a model whereby TBK1 and IKBKE license TAX1BP1-selective autophagy function to inhibit MAVS and RLR signaling. Abbreviations: ATG: autophagy related; BafA1: bafilomycin A1; CALCOCO2: calcium binding and coiled-coil domain 2; GFP: green fluorescent protein; IFA: indirect immunofluorescence assay; IFN: interferon; IκB: inhibitor of nuclear factor kappa B; IKK: IκB kinase; IRF: interferon regulatory factor; KO: knockout; LAMP1: lysosomal associated membrane protein 1; LIR: LC3-interacting region; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MAVS: mitochondrial antiviral signaling protein; MEF: mouse embryonic fibroblast; MOI: multiplicity of infection; IKBKG/NEMO: inhibitor of nuclear factor kappa B kinase regulatory subunit gamma; NFKB: nuclear factor kappa B; OPTN: optineurin; Poly(I:C): polyinosinic-polycytidylic acid; RB1CC1/FIP200: RB1 inducible coiled-coil 1; RIGI: RNA sensor RIG-I; RLR: RIGI-like receptor; SDD-AGE: semi-denaturing detergent-agarose gel electrophoresis; SeV: Sendai virus; SLR: SQSTM1-like receptor; SQSTM1: sequestosome 1; TAX1BP1: Tax1 binding protein 1; TBK1: TANK binding kinase 1; TNF: tumor necrosis factor; TRAF: TNF receptor associated factor; VSV: vesicular stomatitis virus; ZnF: zinc finger.

Endometrial cancer, a common gynecological malignancy, poses significant clinical challenges, particularly in advanced or recurrent cases. TANK-binding kinase 1 (TBK1), a serine/threonine kinase, plays crucial roles in inflammation and immunity by activating nuclear factor (NF)-κB and interferon regulatory factor 3. However, its specific roles in endometrial cancer remain unknown. In this study, we aimed to investigate the anti-cancer effects and underlying mechanisms of amlexanox, a TBK1 inhibitor, against endometrial cancer. The main genetic mutations in TBK1 were found to be mRNA downregulation and missense mutations. Kaplan-Meier plotter analysis revealed that low TBK1 expression was associated with a good prognosis in patients with uterine corpus endometrial carcinoma (UCEC). In vitro experiments demonstrated that TBK1 knockdown or amlexanox significantly inhibited the proliferation, cell cycle progression, and migration of endometrial cancer cells. Furthermore, the inhibitory effects of targeting TBK1 on cancer cell proliferation and migration were mediated by the protein kinase B (AKT)/NF-κB signaling pathway. Xenograft experiments revealed that both amlexanox treatment and TBK1 knockdown effectively suppressed the tumor growth. Overall, this study highlights the potent anti-cancer effects of amlexanox against endometrial cancer by modulating AKT/NF-κB signaling, thus providing a new avenue for the development of novel TBK1-targeting therapeutic strategies for UCEC., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Study Objectives: Obstructive sleep apnea syndrome (OSAS) is closely associated with tumor growth. Chronic intermittent hypoxia (CIH) promotes autophagy and is related to malignant tumor development. However, the role of autophagy in OSAS progression remains unclear., Methods: OSAS datasets (GSE135917 and GSE38792) from GEO were analyzed to identify differentially expressed genes (DEGs) and autophagy-related DEGs (a-DEGs). GO, KEGG, and GSEA were conducted, and a PPI network identified hub genes. CRC datasets from TCGA was used for differential expression and survival analyses, along with GSEA and immune infiltration analysis. CIH-induced autophagy and oxidative stress were investigated in Sprague-Dawley rats using ROS assays. Hub genes were validated in rats and OSAS patient samples., Results: GSEA revealed significant differences in autophagy-related gene expression among OSAS patients. Hub genes ATG5, CASP1, MAPK8, EIF4G1, and TBK1 were identified, with ATG5 and TBK1 validated. A-DEGs were predominantly upregulated in CRC tissues. TBK1 expression in CRC patients was associated with enhanced sensitivity to immunotherapy and CD8+ T cell, macrophage, and regulatory T cell infiltration, potentially influencing the immune microenvironment. The animal experiments showed that CIH increased ROS levels, suggesting that CIH plays a role in autophagy. TBK1 expression was significantly higher in OSAS patients than in controls, and continuous positive airway pressure (CPAP) did not alter TBK1 levels., Conclusions: This study is the first to describe the potential contribution of TBK1 to the development of OSAS and its potential as a novel biomarker and potential therapeutic target for OSAS., (© The Author(s) 2024. Published by Oxford University Press on behalf of Sleep Research Society. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: TANK-binding kinase 1 (TBK1) is a pivotal mediator of innate immunity, activated by receptors such as mitochondrial antiviral signaling protein (MAVS), stimulator of interferon genes (STING), and TIR-domain-containing adaptor inducing interferon-β (TRIF). It modulates immune responses by exerting influence on the type I interferons (IFN-Is) signaling and the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathways, Over the past few years, TBK1 multifaceted role in both immune and inflammatory responses is increasingly recognized., Methods and Results: This review aims to scrutinize how TBK1 operates within the NF-κB pathway and the interferon regulatory transcription factor 3 (IRF3)-dependent IFN-I pathways, highlighting the kinases and other molecules involved in these processes. This analysis reveals the distinctive characteristics of TBK1's involvement in these pathways. Furthermore, it has been observed that the role of TBK1 in exerting anti-inflammatory or pro-inflammatory effects is contingent upon varying pathological conditions, indicating a multifaceted role in immune regulation., Discussion: TBK1's evolving role in various diseases and the potential of TBK1 inhibitors as therapeutic agents are explored. Targeting TBK1 may provide new strategies for treating inflammatory disorders and autoimmune diseases associated with IFN-Is, warranting further investigation.

Loss-of-function (LoF) variants in the TANK binding kinase 1 ( TBK1 ) gene are implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. In this study, we present the first familial cases of ALS and parkinsonism associated with a novel TBK1 variant. We describe two siblings: one diagnosed with classical ALS and the other with a unique syndrome overlapping ALS and parkinsonism. Comprehensive clinical and imaging evaluations supported these diagnoses. Genetic analysis through whole-genome sequencing revealed a previously unknown heterozygous splice site variant in TBK1 . Functional assessments demonstrated that this splice site variant leads to abnormal splicing and subsequent degradation of the mutated TBK1 allele by nonsense-mediated decay, confirming its pathogenic impact. Our findings suggest a broader involvement of TBK1 in neurodegenerative diseases and underscore the need for further research into TBK1's role, advocating for screening for TBK1 variants in similar familial cases.

Leishmania parasites harbor a unique network of circular DNA known as kinetoplast DNA (kDNA). The role of kDNA in leishmania infections is poorly understood. Herein, we show that kDNA delivery to the cytosol of Leishmania major infected THP-1 macrophages provoked increased parasite loads when compared to untreated cells, hinting at the involvement of cytosolic DNA sensors in facilitating parasite evasion from the immune system. Parasite proliferation was significantly hindered in cGAS- STING- and TBK-1 knockout THP-1 macrophages when compared to wild type cells. Nanostring nCounter gene expression analysis on L. major infected wild type versus knockout cells revealed that some of the most upregulated genes including, Granulysin (GNLY), Chitotriosidase-1 (CHIT1), Sialomucin core protein 24 (CD164), SLAM Family Member 7 (SLAMF7), insulin-like growth factor receptor 2 (IGF2R) and apolipoprotein E (APOE) were identical in infected cGAS and TBK1 knockout cells, implying their involvement in parasite control. Amlexanox treatment (a TBK1 inhibitor) of L. major infected wild type cells inhibited both the percentage and the parasite load of infected THP-1 cells and delayed footpad swelling in parasite infected mice. Collectively, these results suggest that leishmania parasites might hijack the cGAS-STING-TBK1 signaling pathway to their own advantage and the TBK1 inhibitor amlexanox could be of interest as a candidate drug in treatment of cutaneous leishmaniasis.

TBK1 is a serine-threonine protein kinase that has been linked to a number of diseases including amyotrophic lateral sclerosis and frontotemporal dementia. Reproducible research on TBK1 has been hampered by the lack of well characterized antibodies. In this study, we characterized 11 commercial antibodies for TBK1 for use in immunoblot, immunofluorescence and immunoprecipitation, using an isogeneic knock-out cell line as a control. We identify antibodies that appear specific for all three applications but invite the readers to interpret the present findings based on their own scientific expertise and use this report as a guide to select the most appropriate antibody for their specific needs.

TBK1 is a serine-threonine protein kinase that has been linked to a number of diseases including amyotrophic lateral sclerosis and frontotemporal dementia. Reproducible research on TBK1 has been hampered by the lack of well characterized antibodies. In this study, we characterized 11 commercial antibodies for TBK1 for use in immunoblot, immunofluorescence and immunoprecipitation, using an isogeneic knock-out cell line as a control. We identify antibodies that appear specific for all three applications but invite the readers to interpret the present findings based on their own scientific expertise and use this report as a guide to select the most appropriate antibody for their specific needs.

Iridoviruses are large DNA viruses which cause great economic losses to the aquaculture industry and serious threats to ecological diversity worldwide. Singapore grouper iridovirus (SGIV), a novel member of the genus Ranavirus, causes high mortality in grouper aquaculture. Previous work on genome annotation demonstrated that SGIV contained numerous uncharacterized or hypothetical open reading frames (ORFs), whose functions remained largely unknown. Here, we reported that the protein encoded by SGIV ORF131R (VP131) was localized predominantly within the endoplasmic reticulum (ER). Ectopic expression of GFP-VP131 significantly enhanced SGIV replication, while VP131 knockdown decreased viral infection in vitro, suggesting that VP131 functioned as a proviral factor during SGIV infection. Overexpression of GFP-VP131 inhibited the interferon (IFN)-1 promoter activity and mRNA level of IFN-related genes induced by poly(I:C), Epinephelus coioides cyclic GMP/AMP synthase (EccGAS)/stimulator of IFN genes (EcSTING), TANK-binding kinase 1 (EcTBK1), or melanoma differentiation-associated gene 5 (EcMDA5), whereas such activation induced by mitochondrial antiviral signaling protein (EcMAVS) was not affected. Moreover, VP131 interacted with EcSTING and degraded EcSTING through both the autophagy-lysosome pathway and ubiquitin-proteasome pathway, and targeted for the K63-linked ubiquitination. Of note, we also found that EcSTING significantly accelerated the formation of GFP-VP131 aggregates in co-transfected cells. Finally, GFP-VP131 inhibited EcSTING- or EcTBK1-induced antiviral activity upon red-spotted grouper nervous necrosis virus (RGNNV) infection. Together, our results demonstrated that the SGIV VP131 negatively regulated the IFN response by inhibiting EcSTING-EcTBK1 signaling for viral evasion. IMPORTANCE STING has been identified as a critical factor participating in the innate immune response which recruits and phosphorylates TBK1 and IFN regulatory factor 3 (IRF3) to induce IFN production and defend against viral infection. However, viruses also distort the STING-TBK1 pathway to negatively regulate the IFN response and facilitate viral replication. Here, we reported that SGIV VP131 interacted with EcSTING within the ER and degraded EcSTING, leading to the suppression of IFN production and the promotion of SGIV infection. These results for the first time demonstrated that fish iridovirus evaded the host antiviral response via abrogating the STING-TBK1 signaling pathway. [ABSTRACT FROM AUTHOR]

Background: There are relatively few data on the genetic spectrum of Chinese frontotemporal dementia (FTD) population.Objective: With the dementia cohort of Peking Union Medical College Hospital, we aim to illustrate the genetic spectrum of FTD patients, as well as the phenotypic heterogeneity of FTD-gene variant carriers.Methods: 204 unrelated, clinically diagnosed FTD patients of Chinese ancestry were enrolled. All the participants received demographic survey, history inquiry, physical examination, cognitive assessment, blood biochemical test, brain CT/MRI, and gene sequencing.Results: 56.4% (115/204) participants were clinically diagnosed with behavioral variant of FTD, 20.6% (42/204) with nonfluent/agrammatic variant primary progressive aphasia (PPA), 20.1% (41/204) with semantic variant PPA, and 2.9% (6/204) with mixed variant PPA. 11.8% (24/204) subjects harbored the potential causative variants in FTD-related genes, including the MAPT (n = 7), TBK1 (n = 7), GRN (n = 2), TBK1+GRN (n = 1), VCP (n = 1), TARDBP (n = 1), UBQLN2 (n = 1), SQSTM1 (n = 1), DCTN1 (n = 1), HNRNPA1 (n = 1), and C9orf72 GGGGCC repeats (n = 1). The TBK1 T31fs, T457fs, K622fs, c.359-1G>A, the VCP P188T, and the GRN P50fs, P439fs were novel pathogenic/likely pathogenic variants. The TBK1 carriers showed a later disease onset and a higher incidence of parietal atrophy relative to the MAPTcarriers.Conclusion: There is genetic and clinical heterogeneity among Chinese FTD population. The TBK1 has a high mutation frequency in Chinese FTD patients. [ABSTRACT FROM AUTHOR]

The cGAS-STING pathway is responsible for cytoplasmic double-stranded DNA (dsDNA) -triggered innate immunity and involved in the pathology of various diseases including infection, autoimmune diseases, neurodegeneration and cancer. Understanding the activation and regulatory mechanisms of this pathway is critical to develop therapeutic strategies toward these diseases. Here, we review the signal transduction, cellular functions and regulations of cGAS and STING, particularly highlighting the latest understandings on the activation of cGAS by dsDNA and/or Manganese (Mn2+), STING trafficking, sulfated glycosaminoglycans (sGAGs)-induced STING polymerization and activation, and also regulation of the cGAS-STING pathway by different biocondensates formed via phase separation of proteins from host cells and viruses. [ABSTRACT FROM AUTHOR]

During an infection, hematopoiesis is altered to increase the output of mature myeloid cells to fight off the pathogen. Despite convincing evidence that hematopoietic stem and progenitor cells (HSPCs) can sense pathogens directly, more mechanistic studies are needed to reveal whether pattern recognition receptor (PRR) signaling initiates myeloid development directly, or indirectly through the production of cytokines by HSPCs that can act in an autocrine/paracrine manner, or by a combination of both direct and indirect mechanisms. In this study, we have used an in vitro model of murine HSPCs to study myeloid differentiation in response to the TLR2 ligand Pam3CSK4 and showed that, besides indirect mechanisms, TLR2 stimulation of HSPCs promotes myelopoiesis directly by initiating a MyD88-dependent signaling. This direct differentiation program involves a combined activation of the transcription factors PU.1, C/EBPβ, and IRF7 driven by TBK1 and PI3K/mTOR. Notably, downstream of MyD88, the activated TBK1 kinase can activate mTOR directly and IRF7 induction is mediated by both TBK1 and mTOR. TLR2 signaling also induces NF-κB dependent IL-6 production that may further induce indirect myeloid differentiation. Our results have identified the direct signaling pathways and the transcription factors involved in macrophage development from HSPCs in response to TLR2 engagement, a critical process to trigger a rapid immune response during infection. TLR2-induced signaling pathways that drive myeloid differentiation in HSPCs. MyD88 is recruited upon Pam3CSK4 binding to TLR1/TLR2, activating TBK1, and the PI3K/mTORC1 pathway. This results in the expression of transcription factors IRF7, PU.1, and C/EBPβ, which drive direct macrophage differentiation. TLR2 signaling also induces NF-κB-dependent release of IL-6 that can act in an autocrine/paracrine manner inducing indirect macrophage differentiation. [ABSTRACT FROM AUTHOR]

Autophagy is an essential process for maintaining cellular homeostasis. Highlighting the importance of proper functioning of autophagy in neurons, disruption of autophagy is a common finding in neurodegenerative diseases. In recent years, evidence has emerged for the role of autophagy in regulating critical axonal functions. In this review, we discuss kinase regulation of autophagy in neurons, and provide an overview of how autophagic kinases regulate axonal processes, including axonal transport and axonal degeneration and regeneration. We also examine mechanisms for disruption of this process leading to neurodegeneration, focusing on the role of TBK1 in pathogenesis of Amyotrophic Lateral Sclerosis. [ABSTRACT FROM AUTHOR]

TRIM (tripartite motif) proteins have been demonstrated to exert critical roles in host defense against different microbial pathogens. Among them, TRIM23 acts as an important regulatory factor in antiviral immune and inflammatory responses, but the roles of fish TRIM23 against virus infection still remain largely unknown. Here, we investigated the characteristics of TRIM23 homolog from orange spotted grouper (Epinephelus coioides) (EcTRIM23). EcTRIM23 encoded a 580 amino acid peptide, which shared 93.1%, 89.73% and 86.36% identity with golden perch (Perca flavescens), zebrafish (Danio rerio) and human (Homo sapiens), respectively. The transcription levels of EcTRIM23 were significantly up-regulated in response to Singapore grouper iridovirus (SGIV) and red-spotted grouper nervous necrosis virus (RGNNV) infection. EcTRIM23 overexpression in vitro significantly inhibited RGNNV and SGIV replication, evidenced by the delayed cytopathic effect (CPE) progression and the decreased expression of viral core genes. EcTRIM23 significantly increased the expression levels of interferon (IFN) related signaling molecules and proinflammatory cytokines, as well as the promoter activities of IFN and NF-kB, suggesting that EcTRIM23 exerted antiviral function by positively regulating host IFN response. Exogenous EcTRIM23 exhibited either diffuse or aggregated localization in grouper cells. After co-transfection, TANK binding kinase 1 (TBK1), TNF receptor associated factor (TRAF) 3 and TRAF4, TRAF5 and TRAF6 were found to interact with EcTRIM23 in grouper cells. Moreover, these proteins could be recruited and co-localized with EcTRIM23 in vitro. Together, our results demonstrated that fish TRIM23 exerted antiviral activity against fish viruses by interacting with multiple host proteins to regulate immune responses. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is one of the most fatal malignant tumors worldwide. Circular RNAs (circRNAs) are a special type of RNA that lacks the 5' and 3' ends. The functional roles of circRNAs in HCC remain largely unknown. Using high-throughput sequencing, we found several differentially expressed circRNAs in HCC tissues compared with nearby normal tissues. Among them, circRNA derived from the LIFR gene, named circLIFR, was significantly downregulated in HCC. Intriguingly, circLIFR overexpression in SK-Hep-1 cells promoted cell growth and invasion. RNA pull-down and mass spectrometry detection revealed circLIFR interacting with TANK binding kinase 1 (TBK1). Anti-TBK1 RIP confirmed the interaction between circLIFR and TBK1. TBK1 is a serine/threonine kinase that regulates several signaling pathways, including the NF-κB pathway. TBK1 inhibitors inhibit NF-κB activation. Overexpression of circLIFR overcame the in-hibitory function of TBK1, resulting in the upregulation of several genes, including MMP13, MMP3, VEGF, and MAPK. This study shows that the downregulation of circLIFR in HCC has a can-cer-promoting effect by interacting with TBK1 to promote the activation of downstream NF-κB pathway genes related to cell proliferation, migration, and invasion. This novel finding reveals the diversity of circRNA functions in HCC and provides novel insights into the role of circRNAs. [ABSTRACT FROM AUTHOR]

The cGAS-STING signaling plays an integral role in the host immune response, and the abnormal activation of cGAS-STING is highly related to various autoimmune diseases. Therefore, targeting the cGAS-STING-TBK1 axis has become a promising strategy in therapy of autoimmune diseases. Herein, we summarized the key pathways mediated by the cGAS-STING-TBK1 axis and various cGAS-STING-TBK1 related autoimmune diseases, as well as the recent development of cGAS, STING, or TBK1 selective inhibitors and their potential application in therapy of cGAS-STING-TBK1 related autoimmune diseases. Overall, the review highlights that inhibiting cGAS-STING-TBK1 signaling is an attractive strategy for autoimmune disease therapy. [ABSTRACT FROM AUTHOR]

The type I interferon (IFN) response is one of the primary defense systems against various pathogens. Although rubella virus (RuV) infection is known to cause dysfunction of various organs and systems, including the central nervous system, little is known about how human neural cells evoke protective immunity against RuV infection, leading to controlling RuV replication. Using cultured human neural cells experimentally infected with RuV RA27/3 strain, we characterized the type I IFN immune response against the virus. RuV infected cultured human neural cell lines and induced IFN-β production, leading to the activation of signal transducer and activator of transcription 1 (STAT1) and the increased expression of IFN-stimulated genes (ISGs). Melanoma-differentiation-associated gene 5 (MDA5), one of the cytoplasmic retinoic acid-inducible gene I (RIG-I)-like receptors, is required for the RuV-triggered IFN-β mRNA induction in U373MG cells. We also showed that upregulation of RuV-triggered ISGs was attenuated by blocking IFN-α/β receptor subunit 2 (IFNAR2) using an IFNAR2-specific neutralizing antibody or by repressing mitochondrial antiviral signaling protein (MAVS) expression using MAVS-targeting short hairpin RNA (shRNA). Furthermore, treating RuV-infected cells with BX-795, a TANK-binding kinase 1 (TBK1)/I kappa B kinase ε (IKKε) inhibitor, robustly reduced STAT1 phosphorylation and expression of ISGs, enhancing viral gene expression and infectious virion production. Overall, our findings suggest that the RuV-triggered type I IFN-mediated antiviral response is essential in controlling RuV gene expression and viral replication in human neural cells. [ABSTRACT FROM AUTHOR]

Toll/IL-1R domain-containing adaptor-inducing IFN-β (TRIF), tumor necrosis factor receptor-associated factor 6 (TRAF6) and TANK-binding kinase 1 (TBK1) are critical signal transducers in toll-like receptors (TLRs) signaling pathway. In the present study, TRIF, TRAF6 and TBK1 were characterized from golden pompano (Trachinotus ovatus), named as TroTRIF, TroTRAF6 and TroTBK1, respectively. The full cDNA length of TroTRIF, TroTRAF6 and TroTBK1 was 2297 bp, 2293 bp, and 2482 bp, which respectively encoded 589, 573 and 723 amino acids. The deduced amino acids sequences of TroTRIF, TroTRAF6 and TroTBK1 contained conserved motifs, similar to their counterparts in other vertebrates. Phylogenetic tree analysis revealed that TroTRIF, TroTRAF6 and TroTBK1 were well clustered with their counterparts in other fish species. Quantitative Real-Time PCR (qPCR) analysis showed that TroTRIF, TroTBK1 and TroTRAF6 were detected in all examined tissues of healthy fish, but shared distinct transcript levels. Moreover, the expressions of TroTRIF, TroTBK1 and TroTRAF6 were generally induced by polyriboinosinic-polyribocytidylic acid (polyI:C), lipopolysaccharide (LPS), and Vibrio alginolyticus stimulation in vivo , indicating their critical roles in the immune defense of golden pompano against pathogen invasion. Our results provide valuable information for understanding the functions of these genes in golden pompano. • TRIF, TRAF6 and TBK1 genes were cloned from golden pompano. • Sequence features of TRIF, TRAF6 and TBK1 were analyzed. • Expressional patterns of TRIF, TRAF6 and TBK1 in normal tissues were analyzed. • Expressions of TRIF, TRAF6 and TBK in spleen and HK following LPS, polyI:C, and V. alginolyticus challenge were analyzed. [ABSTRACT FROM AUTHOR]

A GO pathway enrichment analysis of PDAC cells with knockdown of I TBK1 i or I BACH1 i suggested that I TBK1 i and I BACH1 i both regulate cellular iron ion homeostasis and cell migration. Using our previously published data of RNA-seq in AsPC-1 cells with or without I BACH1 i knockdown [[46]], there were 102 common upregulated genes and 181 common downregulated genes in I TBK1 i -silenced and I BACH1 i -silenced AsPC-1 cells (Figure 2A,B). The expression of these genes is also reduced upon I BACH1 i knockdown in these cells [[46]], suggesting that I TBK1 i promotes metastatic process including cell migration via enhancing the function of I BACH1 i . 3.3. TBK1-BACH1 Pathway Regulates Iron Homeostasis and Cell Migration To further investigate the regulatory relationship between I TBK1 i and I BACH1 i , we knocked down I TBK1 i in AsPC-1 cells and carried out an RNA-seq analysis. [Extracted from the article]

The cGAS-STING signaling plays an integral role in the host immune response, and the abnormal activation of cGAS-STING is highly related to various autoimmune diseases. Therefore, targeting the cGAS-STING-TBK1 axis has become a promising strategy in therapy of autoimmune diseases. Herein, we summarized the key pathways mediated by the cGAS-STING-TBK1 axis and various cGAS-STING-TBK1 related autoimmune diseases, as well as the recent development of cGAS, STING, or TBK1 selective inhibitors and their potential application in therapy of cGAS-STING-TBK1 related autoimmune diseases. Overall, the review highlights that inhibiting cGAS-STING-TBK1 signaling is an attractive strategy for autoimmune disease therapy.

Autophagy is an essential process for maintaining cellular homeostasis. Highlighting the importance of proper functioning of autophagy in neurons, disruption of autophagy is a common finding in neurodegenerative diseases. In recent years, evidence has emerged for the role of autophagy in regulating critical axonal functions. In this review, we discuss kinase regulation of autophagy in neurons, and provide an overview of how autophagic kinases regulate axonal processes, including axonal transport and axonal degeneration and regeneration. We also examine mechanisms for disruption of this process leading to neurodegeneration, focusing on the role of TBK1 in pathogenesis of Amyotrophic Lateral Sclerosis.

Ginsenoside Rc (GRc), an active component isolated from ginseng, has been reported to have anti-inflammatory properties. However, the potential mechanism of its effect on rheumatoid arthritis (RA) is not reported. The present study established the RA model by injection of complete Freund’s adjuvant in the hind paw. GRc was administrated by gavage daily. The results showed that GRc ameliorated the swelling rate of both hind paws and reduced the arthritis score in rats. Meanwhile, GRc inhibited cartilage damage and inflammatory cell infiltration in the joint tissue. Furthermore, GRc significantly decreased the concentration of pro-inflammatory cytokines in the joint tissue of rats. Additionally, GRc downregulated the NF-κB signaling pathway. In conclusion, these findings show that GRc remarkably reduced cartilage damage and inflammatory response in the RA rat model by inhibiting of NF-κB signaling pathway.

TBK1 is a serine-threonine protein kinase that has been linked to a number of diseases including amyotrophic lateral sclerosis and frontotemporal dementia. Reproducible research on TBK1 has been hampered by the lack of well characterized antibodies. In this study, we characterized 11 commercial antibodies for TBK1 for use in immunoblot, immunofluorescence and immunoprecipitation, using an isogeneic knock-out cell line as a control. We identify antibodies that appear specific for all three applications but invite the readers to interpret the present findings based on their own scientific expertise and use this report as a guide to select the most appropriate antibody for their specific needs.

Abstract Utilising Checkpoint Kinase 1 (Chk1) inhibitors to increase cytoplasmic DNA may be a potential strategy to increase the sensitivity of tumours to immune checkpoint modulators. The appearance of DNA in the cytoplasm can drive Cyclic GMP-AMP Synthase-2′,3′-Cyclic Guanosine Monophosphate–Adenosine Monophosphate-Stimulator of Interferon Genes (cGAS-cGAMP-STING) inflammatory, anti-tumour T-cell activity via a type I interferon (IFN) and nuclear factor-κB response. In the THP1-Dual reporter cell line, the STING agonist cGAMP activated both reporters, and increased phosphorylation of the innate immune pathway signallers Tank Binding Kinase 1 (TBK1) and Interferon Regulatory Factor (IRF) 3. Inhibition of Chk1 increased TBK1 but not IRF3 phosphorylation and did not induce IRF or NF-κB reporter activation. cGAMP induced a Type I IFN response in THP1 cells whereas inhibition of Chk1 did not. HT29 or HCC1937 cell treatment with a Chk1 inhibitor increased cytoplasmic dsDNA in treated HCC1937 but not HT29 cells and increased IRF reporter activation in cocultured THP1-Dual cells. HT29 cells pre-treated with gemcitabine or camptothecin had elevated cytoplasmic dsDNA and IRF reporter activation in cocultured THP1-Dual cells. Camptothecin or gemcitabine plus a Chk1 inhibitor increased cytoplasmic dsDNA but Chk1 inhibition suppressed IRF reporter activation in cocultured THP1 cells. In THP1-Dual cells treated with cGAMP, Chk1 inhibition suppressed the activation of the IRF reporter compared to cGAMP alone. These results suggest that, in some cellular models, there is little evidence to support the combination of Chk1 inhibitors with immune checkpoint modulators and, in some combination regimes, may even prove deleterious.

Introduction: While its innate immune function has been known, recent works of literature have focused on the role of Tank binding kinase 1 (TBK1) in regulating autophagy and it is unknown whether TBK1 protects against intervertebral disc degeneration (IVDD) through affecting autophagy. Objectives: Here, we aim to explore whether TBK1 is implicated in the pathogenesis of IVDD, and investigated the potential mechanism. Methods: Western blotting and immunohistochemistry were used to detect the TBK1 expression in human and rat NP tissue. After TBK1 overexpression in NP cells with lentivirus transfection, autophagic flux, apoptosis and senescence percentage were assessed. Si-RNA , a utophagy inhibitors and protein phosphatase inhibitors were applied to study the mechanism of autophagy regulation. In vivo study, we further evaluated the therapeutic action of lentivirus-TBK1(Lv-TBK1)injection in a rodent IVDD model. Results: The TBK1 level was reduced in rat and human NP tissue. TBK1 overexpression protected against apoptosis and premature senescence. These functions of TBK1 were abolished by chloroquine-medicated autophagy inhibition.P-TBK1, an activation form of TBK, is involved in selective autophagy through directly phosphorylating P62 at Ser 403, and the activation of TBK1 is also dependent on Parkin manner. TBK1 also activated NPCs autophagy to relieve puncture injury in vivo. Conclusion: We demonstrated that TBK1 overexpression attenuated senescence and apoptosis and promoted NPCs survival via upregulating autophagy. TBK1 represents a promising avenue for IVDD treatment.

Members of the inhibitor of nuclear factor kappa-B kinase (IKK) family are pivotal components of the innate immune signaling pathway responsible for regulating immune and inflammatory responses. Nevertheless, the various roles that IKKs play in the physiology of invertebrates, particularly marine mollusks, remain largely unexplored. In this study, an IKK gene was cloned from the Zhikong scallop, Chlamys farreri , and denoted as CfIKK2. CfIKK2 belongs to the TANK-binding kinase 1 (TBK1)/IKKε family. Real-time quantitative reverse transcription-polymerase chain reaction analysis showed that CfIKK2 was expressed in various scallop tissues and that its transcript levels substantially increased under different pathogenic stress conditions (including lipopolysaccharide, peptidoglycan, poly(I:C), acute viral necrosis virus, and Vibrio challenge). Co-immunoprecipitation experiments revealed that CfIKK2 interacts with MyD88 (a crucial adaptor in the Toll-like receptor signaling pathway) proteins through its C-terminal TBK1 coiled-coil domain 1. Moreover, CfIKK2 has been shown to interact with itself. In HEK293T cells, CfIKK2 overexpression resulted in an augmentation of mitogen-activated protein kinase phosphorylation. Furthermore, overexpression of CfIKK2 resulted in the activation of interferon reporter genes. In summary, our findings offer valuable insights into the mechanisms through which CfIKK2 responds to stress generated by pathogen-associated molecular patterns, participates in Toll-like receptor signaling, and ultimately activates some of the key cytokines involved in innate immunity in C. farreri. As a critical signaling molecule and immunoregulatory factor, CfIKK2 plays a vital role in the innate immune system of the Zhikong scallop. • CfIKK2 was cloned and characterized in the Zhikong scallop Chlamys farreri. • CfIKK2 gene was expressed across various tissues and exhibited responsive behavior to multiple pathogen-induced stresses. • CfIKK2 interacts with the MyD88 proteins and facilitated the formation of homodimers. • Overexpression of CfIKK2 amplified the phosphorylation of MAPKs and activated interferon reporter genes. [ABSTRACT FROM AUTHOR]

The production of type I interferon is tightly regulated to prevent excessive immune activation. However, the role of selective autophagy receptor SQSTM1 in this regulation in teleost remains unknown. In this study, we cloned the triploid fish SQSTM1 (3nSQSTM1), which comprises 1371 nucleotides, encoding 457 amino acids. qRT-PCR data revealed that the transcript levels of SQSTM1 in triploid fish were increased both in vivo and in vitro following spring viraemia of carp virus (SVCV) infection. Immunofluorescence analysis confirmed that 3nSQSTM1 was mainly distributed in the cytoplasm. Luciferase reporter assay results showed that 3nSQSTM1 significantly blocked the activation of interferon promoters induced by 3nMDA5, 3nMAVS, 3nTBK1, and 3nIRF7. Co-immunoprecipitation assays further confirmed that 3nSQSTM1 could interact with both 3nTBK1 and 3nIRF7. Moreover, upon co-transfection, 3nSQSTM1 significantly inhibited the antiviral activity mediated by TBK1 and IRF7. Mechanistically, 3nSQSTM1 decreased the TBK1 phosphorylation and its interaction with 3nIRF7, thereby suppressing the subsequent antiviral response. Notably, we discovered that 3nSQSTM1 also interacted with SVCV N and P proteins, and these viral proteins may exploit 3nSQSTM1 to further limit the host's antiviral innate immune responses. In conclusion, our study demonstrates that 3nSQSTM1 plays a pivotal role in negatively regulating the interferon signaling pathway by targeting 3nTBK1 and 3nIRF7. • 3nSQSTM1 negatively regulates the interferon signaling. • 3nSQSTM1 interacts with 3nTBK1 and 3nIRF7. • 3nSQSTM1 interacts with SVCV N and P proteins. [ABSTRACT FROM AUTHOR]

Growing evidence highlights that tripartite motif (TRIM) family members exert crucial functions in host defense upon infection with microbial pathogens. Of note, the roles of a subfamily of fish-specific TRIM (FTR, also named as finTRIM) which have no true orthologues in mammals were largely unexplored. In this study, a novel FTR gene from grouper (EcFTR14) was identified, and its effects on fish virus infection and host interferon response were investigated. EcFTR14 contained RING, B-Box, and PRY-SPRY domains, and shared 54.81% identity to zebrafish FTR14. The transcription levels of EcFTR14 were markedly induced upon fish virus infection. EcFTR14 was mainly localized in the cytoplasm as small spots or bright aggregates. The overexpression of EcFTR14 could markedly enhance the replication of RGNNV or SGIV. Moreover, overexpression of EcFTR14 reduced the mRNA level of IFN-associated immune signaling molecules, suggesting that the antiviral action of EcFTR14 was due to the negative regulation on IFN response. EcFTR14 was found to interact with EcTBK1, EcIRF3 and EcIRF7, but not with EcSTING. Overexpression of EcFTR14 markedly suppressed the transcription levels of IFN-signaling related molecules evoked by EcSTING and EcTBK1. In addition, overexpression of EcFTR14 could degrade EcTBK1, EcIRF3 and EcIRF7 in a dose-dependent manner, that resulted in the suppression of antiviral effects induced by EcIRF3 and EcTBK1. Collectively, our findings illuminated that EcFTR14, a novel member of FTR family, acted as a pro-viral factor through negatively regulating targeting TBK1-IRF3 activated antviral action. The present study will for the first time shed light on the regulatory roles of FTR14 in innate immune response upon fish virus infection. • EcFTR14 was a novel FTR protein which shared 54.81% identity to zebrafish FTR14. • EcFTR14 were significantly up-regulated upon SGIV and RGNNV infection. • EcFTR14 acted as a pro-viral factor during SGIV and RGNNV infection. • EcFTR14 interacted with EcTBK1, EcIRF3, EcIRF7, and negatively regulated IFN response. • EcFTR14 weakened the antiviral effects induced by EcIRF3 and EcTBK1. [ABSTRACT FROM AUTHOR]

Candida albicans stably colonizes humans but is the leading cause of hospital-acquired fungemia. Traditionally, masking immunogenic moieties has been viewed as a tactic for immune evasion. Here, we demonstrate that C. albicans blocks type I interferon (IFN-I) signaling via translocating an effector protein Cmi1 into host cells. Mechanistically, Cmi1 binds and inhibits TANK-binding kinase 1 (TBK1) to abrogate IFN-regulatory factor 3 (IRF3) phosphorylation, thereby suppressing the IFN-I cascade. Murine infection with a cmi1 mutant displays an exaggerated IFN-I response in both kidneys and bone-marrow-derived macrophages, leading to rapid fungal clearance and host survival. Remarkably, the lack of CMI1 compromises gut commensalism and increases IFN-I response in mouse colonic cells. These phenotypes of cmi1 are rescued by the depletion of IFN-I receptor. This work establishes the importance of TBK1 inhibition in fungal pathogenesis and reveals that a human commensal-pathogenic fungus significantly impacts host immunity during gut colonization and infection via delivering effector proteins into host cells. [Display omitted] • Candida albicans dampens type I IFN response in murine kidneys • C. albicans secretes an effector protein Cmi1 into host cytosol • Cmi1 binds TBK1 to abrogate IRF3 phosphorylation and IFN-I activation • Cmi1 targeting of TBK1 promotes virulence and gut colonization of C. albicans Luo et al. identify an effector protein Cmi1 in the human commensal-pathogenic fungus Candida albicans. Cmi1 targets TBK1 to abrogate type I interferon response. This work reveals that C. albicans significantly suppresses host immunity during gut colonization and infection, which could impact human health and disease other than causing infection. [ABSTRACT FROM AUTHOR]

Singapore grouper iridovirus (SGIV) belongs to the family Iridoviridae and the genus Ranavirus, which is a large cytoplasmic DNA virus. Infection of grouper with SGIV can cause hemorrhage and swelling of the spleen of the fish. Previous work on genome annotation demonstrated that SGIV contained numerous uncharacterized or hypothetical open reading frames (ORFs), whose functions remained largely unknown. In the present study, the protein encoded by SGIV ORF128 (VP128) was identified. VP128 is predominantly localized within the endoplasmic reticulum (ER). Overexpression of VP128 significantly promoted SGIV replication. VP128 inhibited the interferon (IFN)-3 promoter activity and mRNA level of IFN-related genes induced by poly(I:C), Epinephelus coioides cyclic GMP/AMP synthase (EccGAS)/stimulator of IFN genes (EcSTING), and TANK-binding kinase 1 (EcTBK1). Moreover, VP128 interacted with EcSTING and EcTBK1. The interaction between VP128 and EcSTING was independent of any specific structural domain of EcSTING. Together, our results demonstrated that SGIV VP128 negatively regulated the IFN response by inhibiting EcSTING-EcTBK1 signaling for viral evasion. • VP128 is predominantly localized within the endoplasmic reticulum (ER). • Overexpression of VP128 significantly promoted SGIV replication. • VP128 interacts with EcSTING and EcTKB1, but not EccGAS. [ABSTRACT FROM AUTHOR]

Background: Infections by viruses including severe acute respiratory syndrome coronavirus 2 could cause organ inflammations such as myocarditis, pneumonia and encephalitis. Innate immunity to viral nucleic acids mediates antiviral immunity as well as inflammatory organ injury. However, the innate immune mechanisms that control viral induced organ inflammations are unclear. Methods: To understand the role of the E3 ligase TRIM18 in controlling viral myocarditis and organ inflammation, wild-type and Trim18 knockout mice were infected with coxsackievirus B3 for inducing viral myocarditis, influenza A virus PR8 strain and human adenovirus for inducing viral pneumonia, and herpes simplex virus type I for inducing herpes simplex encephalitis. Mice survivals were monitored, and heart, lung and brain were harvested for histology and immunohistochemistry analysis. Real-time PCR, co-immunoprecipitation, immunoblot, enzyme-linked immunosorbent assay, luciferase assay, flow cytometry, over-expression and knockdown techniques were used to understand the molecular mechanisms of TRIM18 in regulating type I interferon (IFN) production after virus infection in this study. Results: We find that knockdown or deletion of TRIM18 in human or mouse macrophages enhances production of type I IFN in response to double strand (ds) RNA and dsDNA or RNA and DNA virus infection. Importantly, deletion of TRIM18 protects mice from viral myocarditis, viral pneumonia, and herpes simplex encephalitis due to enhanced type I IFN production in vivo. Mechanistically, we show that TRIM18 recruits protein phosphatase 1A (PPM1A) to dephosphorylate TANK binding kinase 1 (TBK1), which inactivates TBK1 to block TBK1 from interacting with its upstream adaptors, mitochondrial antiviral signaling (MAVS) and stimulator of interferon genes (STING), thereby dampening antiviral signaling during viral infections. Moreover, TRIM18 stabilizes PPM1A by inducing K63-linked ubiquitination of PPM1A. Conclusions: Our results indicate that TRIM18 serves as a negative regulator of viral myocarditis, lung inflammation and brain damage by downregulating innate immune activation induced by both RNA and DNA viruses. Our data reveal that TRIM18 is a critical regulator of innate immunity in viral induced diseases, thereby identifying a potential therapeutic target for treatment. [ABSTRACT FROM AUTHOR]

Renal fibrosis is an important pathological biomarker of chronic kidney disease (CKD). Stimulator of interferon genes/TANK binding kinase 1 (STING/TBK1) axis has been identified as the main regulator of innate immune response and closely related to fibrotic disorder. However, the role of STING/TBK1 signaling pathway in kidney fibrosis is still unknown. In this study, we investigated the effect of pharmacological inhibition of STING/TBK1 signaling on renal fibrosis induced by folic acid (FA). In mice, TBK1 was significantly activated in interstitial cells of FA-injured kidneys, which was markedly inhibited by H-151 (a STING inhibitor) treatment. Specifically, pharmacological inhibition of STING impaired bone marrow-derived fibroblasts activation and macrophage to myofibroblast transition in folic acid nephropathy, leading to reduction of extracellular matrix proteins expression, myofibroblasts formation and development of renal fibrosis. Furthermore, pharmacological inhibition of TBK1 by GSK8612 reduced myeloid myofibroblasts accumulation and impeded macrophage to myofibroblast differentiation, resulting in less deposition of extracellular matrix protein and less severe fibrotic lesion in FAinjured kidneys. In cultured mouse bone marrow-derived monocytes, TGF-β1 activated STING/TBK1 signaling. This was abolished by STING or TBK1 inhibitor administration. In addition, GSK8612 treatment decreased levels of α-smooth muscle actin and extracellular matrix proteins and prevents bone marrow-derived macrophages to myofibroblasts transition in vitro. Collectively, our results revealed that STING/TBK1 signaling has a critical role in bone marrow-derived fibroblast activation, macrophages to myofibroblasts transition, and kidney fibrosis progression. [ABSTRACT FROM AUTHOR]

TRAF-associated NF-κB activator (TANK)-binding kinase 1 (TBK1), a nonclassical IκB kinase (IKK), and its effect on inflammation have not been entirely clarified. Here, we identified that TBK1 participates in the catabolism of glutamine by mediating the phosphorylation of receptor-interacting protein kinase 3 (RIPK3) and promoting macrophage endotoxin tolerance (ET). We found that the TBK1 protein directly interacts with the RIPK3 protein and mediates the phosphorylation of RIPK3 in macrophages. Activated RIPK3 can directly bind to glutamate dehydrogenase 1 (GLUD1), which is known to be a critical enzyme for catalyzing glutamine decomposition, to improve its catalytic activity and increase the production of α-ketoglutarate (α-KG) in macrophages. α-KG generated from glutaminolysis can promote M2 activation and restrict M1 polarization, which plays a crucial role in promoting lipopolysaccharide (LPS)-induced ET. As a result of TBK1 regulating the phosphorylation level of RIPK3, overexpressed TBK1 could enhance the tolerance of macrophages to endotoxin through glutaminolysis. Overall, these findings reveal a novel mechanism for the metabolic control of inflammation and for the induction of ET by modulating glutamine metabolism. • TBK1 mediates inflammatory regulation in endotoxin tolerance through protein phosphorylation. • Activated RIPK3 promotes the enzyme activity of GLUD to strengthen the effect of α-KG resulting in inducing ET. • TBK1 can mediate the phosphorylation of RIPK3, thereby inducing GLUD1 to decompose glutamine to produce α-KG. [ABSTRACT FROM AUTHOR]

African swine fever virus (ASFV) encodes more than 150 proteins, which establish complex interactions with the host for the benefit of the virus in order to evade the host's defenses. However, currently, there is still a lack of information regarding the roles of the viral proteins in host cells. Here, our data demonstrated that ASFV structural protein p17 exerts a negative regulatory effect on cGAS-STING signaling pathway and the STING signaling dependent anti-HSV1 and anti-VSV functions. Further, the results indicated that ASFV p17 was located in ER and Golgi apparatus, and interacted with STING. ASFV p17 could interfere the STING to recruit TBK1 and IKK∈ through its interaction with STING. It was also suggested that the transmembrane domain (amino acids 39-59) of p17 is required for interacting with STING and inhibiting cGAS-STING pathway. Additionally, with the p17 specific siRNA, the ASFV induced IFN-β, ISG15, ISG56, IL-6 and IL-8 gene transcriptions were upregulated in ASFV infected primary porcine alveolar macrophages (PAMs). Taken together, ASFV p17 can inhibit the cGAS-STING pathway through its interaction with STING and interference of the recruitment of TBK1 and IKK∈. Our work establishes the role of p17 in the immune evasion and thus provides insights on ASFV pathogenesis. [ABSTRACT FROM AUTHOR]

Porcine sapelovirus (PSV) is the causative pathogen of reproductive obstacles, acute diarrhea, respiratory distress, or severe polioencephalomyelitis in swine. Nevertheless, the pathogenicity and pathogenic mechanism of PSV infection are not fully understood, which hinders disease prevention and control. In this study, we found that PSV was sensitive to type I interferon (IFN-β). However, PSV could not activate the IFN-β promoter and induce IFN-β mRNA expression, indicating that PSV has evolved an effective mechanism to block IFN-β production. Further study showed that PSV inhibited the production of IFN-β by cleaving mitochondrial antiviral signaling (MAVS) and degrading melanoma differentiation-associated gene 5 (MDA5) and TANK-binding kinase 1 (TBK1) through viral 3Cpro. In addition, our study demonstrated that PSV 3Cpro degrades MDA5 and TBK1 through its protease activity and cleaves MAVS through the caspase pathway. Collectively, our results revealed that PSV inhibits the production of type I interferon to escape host antiviral immunity through cleaving and degrading the adaptor molecules. [ABSTRACT FROM AUTHOR]

Background: Frontotemporal dementia (FTD) is a neurodegenerative disease, resulting in progressive problems in language and/or behaviour and is often diagnosed before 65 years of age. Ubiquitin positive protein aggregates in the brain are among the key pathologic hallmarks of frontotemporal lobar degeneration (FTLD) postmortem. The TANK-binding kinase 1 gene (TBK1) is on the list of genes that can contribute to the development of FTD as well as the related neurodegenerative disease amyotrophic lateral sclerosis (ALS). Methods: In this study, using an array of clinical and neuropathological data combined with biochemical and proteomics assays, we analyze the TBK1 splice-mutation (c.1340 + 1G > A) in a Swedish family with a history of FTD and ALS. We also explore the K63 ubiquitination landscape in post-mortem brain tissue and fibroblast cultures. Results: The intronic (c.1340 + 1G > A) mutation in TBK1 results in haploinsufficiency and affects the activity of the protein in symptomatic and pre-symptomatic mutation carriers. Conclusion: Our results suggest that the mutation leads to a significant reduction of TBK1 activity and induce alterations in K63 ubiquitination profile of the cell already in the presymptomatic stages. [ABSTRACT FROM AUTHOR]

Aims: Acute myocardial infarction (MI), caused by acute coronary artery obstruction, is a common cardiovascular event leading to mortality. Nuclear dot protein 52 (NDP52) is an essential selective autophagy adaptor, although its function in MI is still obscure. This study was designed to examine the function of NDP52 in MI and the associated mechanisms. Results: Our results revealed that MI challenge overtly impaired myocardial geometry and systolic function, along with cardiomyocyte apoptosis, myocardial interstitial fibrosis, and mitochondrial damage, and NDP52 nullified such devastating responses. Further studies showed that the blockade of mitochondrial clearance is related to MI-induced buildup of damaged mitochondria. Mechanistic approaches depicted that 7-day MI induced abnormal mitophagy flux, resulting in poor lysosomal clearance of injured mitochondria. NDP52 promoted mitophagy flux through the recruitment of Ras-associated protein RAB7 (RAB7) and TANK-binding kinase 1 (TBK1). On protein co-localization, TBK1 phosphorylated RAB7, in line with the finding that chloroquine or a TBK1 inhibitor reversed NDP52-dependent beneficial responses. Innovation: This study denoted a novel mechanism that NDP52 promotes cardioprotection against ischemic heart diseases through interaction with TBK1 and RAB7, leading to RAB7 phosphorylation, induction of mitophagy to clear ischemia-induced impaired mitochondria, thus preventing cardiomyocyte apoptosis in MI. Conclusion: Our results indicate that NDP52 promotes autophagic flux and clears damaged mitochondria to diminish reactive oxygen species and cell death in a TBK1/RAB7-dependent manner and thus limits MI-induced injury. Antioxid. Redox Signal. 36, 1119–1135. [ABSTRACT FROM AUTHOR]

Duck enteritis virus (DEV) can infect several types of waterfowl can cause high mortality and huge economic losses to the global waterfowl industry. Type I interferons (IFN) are important for host defense against virus infection through induction of antiviral effector molecules. TANK-binding kinase 1 (TBK1) is a key kinase required for the induction of type I IFNs; however, the role of TBK1 on DEV infection remains unclear. Here, we observed that the expression levels of TBK1 and IFN-β were upregulated during DEV infection in vivo and in vitro. Thus, the function of TBK1 on DEV infection was determined. The results showed that overexpression of TBK1 reduced DEV infection and knockdown of TBK1 resulted in the increased of DEV infection. Additionally, TBK1 overexpression upregulated the expression of IFN-β and a few interferon-stimulated genes (ISGs), which thus inhibited the synthesis of DEV glycoprotein B. On the other hand, the TBK1 inhibitor Amlexanox down-regulated the expression levels of IFN-β and IRF3. Interestingly, the expression levels of MAVS and GSK-3β were decreased in the cells treated with Amlexanox. Furthermore, overexpression of TBK1 activated the expression of upstream molecules MAVS and GSK-3β. Whereas, the expression of TBK1, IRF3 and IFN-β was inhibited by the GSK-3β inhibitor SB216763. Our findings suggest that DEV–stimulated TBK1 may be involved in defense against DEV infection. [ABSTRACT FROM AUTHOR]

African swine fever is a lethal hemorrhagic disease of pigs caused by African swine fever virus (ASFV), which greatly threatens the pig industry in many countries. Deletion of virulence-associated genes to develop live attenuated ASF vaccines is considered to be a promising strategy. A recent study has revealed that the A137R gene deletion results in ASFV attenuation, but the underlying mechanism remains unknown. To elucidate the mechanism of the A137R gene regulating ASFV virulence, an ASFV mutant with the A137R gene deleted (ASFV-ΔA137R) was generated based on the wild-type ASFV HLJ/2018 strain (ASFV-WT). Using transcriptome sequencing analysis, we found that ASFV-ΔA137R induced higher type I interferon (IFN) production in primary porcine alveolar macrophages (PAMs) than did ASFV-WT. Overexpression of the A137R protein (pA137R) inhibited the activation of IFN-β or IFNstimulated response element. Mechanistically, pA137R interacts with TANK-binding kinase 1 (TBK1) and promotes the autophagy-mediated lysosomal degradation of TBK1, which blocks the nuclear translocation of interferon regulator factor 3, leading to decreased type I IFN production. Taken together, our findings clarify that pA137R negatively regulates the cGAS-STING-mediated IFN-β signaling pathway via the autophagy-mediated lysosomal degradation of TBK1, which highlights the involvement of pA137R regulating ASFV virulence. [ABSTRACT FROM AUTHOR]

In recent years, considerable progress has been made in the study of glaucoma, especially primary open angle glaucoma(POAG). A series of POAG genes has been identified through genetic linkage analysis and genome-wide association studies(GWAS), which significantly advanced the study of glaucoma genetics. The latest perspective suggests that glaucoma is a disease of the central nervous system(CNS). A large number of basic clinical studies have demonstrated the close association between CNS disease and glaucoma. Among these studies, discoveries related to genetics are of prominence.

Renal fibrosis is an important pathological biomarker of chronic kidney disease (CKD). Stimulator of interferon genes/TANK binding kinase 1 (STING/TBK1) axis has been identified as the main regulator of innate immune response and closely related to fibrotic disorder. However, the role of STING/TBK1 signaling pathway in kidney fibrosis is still unknown. In this study, we investigated the effect of pharmacological inhibition of STING/TBK1 signaling on renal fibrosis induced by folic acid (FA). In mice, TBK1 was significantly activated in interstitial cells of FA-injured kidneys, which was markedly inhibited by H-151 (a STING inhibitor) treatment. Specifically, pharmacological inhibition of STING impaired bone marrow-derived fibroblasts activation and macrophage to myofibroblast transition in folic acid nephropathy, leading to reduction of extracellular matrix proteins expression, myofibroblasts formation and development of renal fibrosis. Furthermore, pharmacological inhibition of TBK1 by GSK8612 reduced myeloid myofibroblasts accumulation and impeded macrophage to myofibroblast differentiation, resulting in less deposition of extracellular matrix protein and less severe fibrotic lesion in FA-injured kidneys. In cultured mouse bone marrow-derived monocytes, TGF-β1 activated STING/TBK1 signaling. This was abolished by STING or TBK1 inhibitor administration. In addition, GSK8612 treatment decreased levels of α-smooth muscle actin and extracellular matrix proteins and prevents bone marrow-derived macrophages to myofibroblasts transition in vitro. Collectively, our results revealed that STING/TBK1 signaling has a critical role in bone marrow-derived fibroblast activation, macrophages to myofibroblasts transition, and kidney fibrosis progression.

ABSTRACT For RNA virus families except Picornaviridae, viral RNA sensing includes Toll-like receptors and/or RIG-I. Picornavirus RNAs, whose 5′ termini are shielded by a genome-linked protein, are predominately recognized by MDA5. This has important ramifications for adaptive immunity, as MDA5-specific patterns of type-I interferon (IFN) release are optimal for CD4+T cell TH1 polarization and CD8+T cell priming. We are exploiting this principle for cancer immunotherapy with recombinant poliovirus (PV), PVSRIPO, the type 1 (Sabin) PV vaccine containing a rhinovirus type 2 internal ribosomal entry site (IRES). Here we show that PVSRIPO-elicited MDA5 signaling is preceded by early sensing of the IRES by the double-stranded (ds)RNA-activated protein kinase (PKR). PKR binding to IRES stem-loop domains 5–6 led to dimerization and autoactivation, displaced host translation initiation factors, and suppressed viral protein synthesis. Early PKR-mediated antiviral responses tempered incipient viral translation and the activity of cytopathogenic viral proteinases, setting up accentuated MDA5 innate inflammation in response to PVSRIPO infection. IMPORTANCE Among the RIG-I-like pattern recognition receptors, MDA5 stands out because it senses long dsRNA duplexes independent of their 5′ features (RIG-I recognizes viral [v]RNA 5′-ppp blunt ends). Uniquely among RNA viruses, the innate defense against picornaviruses is controlled by MDA5. We show that prior to engaging MDA5, recombinant PV RNA is sensed upon PKR binding to the viral IRES at a site that overlaps with the footprint for host translation factors mediating 40S subunit recruitment. Our study demonstrates that innate antiviral type-I IFN responses orchestrated by MDA5 involve separate innate modules that recognize distinct vRNA features and interfere with viral functions at multiple levels.

Porcine sapelovirus (PSV) is the causative pathogen of reproductive obstacles, acute diarrhea, respiratory distress, or severe polioencephalomyelitis in swine. Nevertheless, the pathogenicity and pathogenic mechanism of PSV infection are not fully understood, which hinders disease prevention and control. In this study, we found that PSV was sensitive to type I interferon (IFN-β). However, PSV could not activate the IFN-β promoter and induce IFN-β mRNA expression, indicating that PSV has evolved an effective mechanism to block IFN-β production. Further study showed that PSV inhibited the production of IFN-β by cleaving mitochondrial antiviral signaling (MAVS) and degrading melanoma differentiation-associated gene 5 (MDA5) and TANK-binding kinase 1 (TBK1) through viral 3Cpro. In addition, our study demonstrated that PSV 3Cpro degrades MDA5 and TBK1 through its protease activity and cleaves MAVS through the caspase pathway. Collectively, our results revealed that PSV inhibits the production of type I interferon to escape host antiviral immunity through cleaving and degrading the adaptor molecules.

Cytosolic RNA/DNA sensing elicits primary defense against viral pathogens. Interferon regulatory factor 3 (IRF3), a key signal mediator/transcriptional factor of the antiviral-sensing pathway, is indispensible for interferon production and antiviral defense. However, how the status of IRF3 activation is controlled remains elusive. Through a functional screen of the human kinome, we found that mammalian sterile 20-like kinase 1 (Mst1), but not Mst2, profoundly inhibited cytosolic nucleic acid sensing. Mst1 associated with IRF3 and directly phosphorylated IRF3 at Thr75 and Thr253. This Mst1-mediated phosphorylation abolished activated IRF3 homodimerization, its occupancy on chromatin, and subsequent IRF3-mediated transcriptional responses. In addition, Mst1 also impeded virus-induced activation of TANK-binding kinase 1 (TBK1), further attenuating IRF3 activation. As a result, Mst1 depletion or ablation enabled an enhanced antiviral response and defense in cells and mice. Therefore, the identification of Mst1 as a novel physiological negative regulator of IRF3 activation provides mechanistic insights into innate antiviral defense and potential antiviral prevention strategies.

The tuber of Coeloglossum viride var. bracteatum is a Tibetan medicine that has been used for generations as a tonic for Yang and Qi, tranquilizing, to enhance intelligence and to promote longevity. We have previously characterized the constituents of Coeloglossum viride var. bracteatum extract (CE) and investigated its anti-Alzheimer's disease (AD) effect in mice models. However, the exact role of CE in Parkinson's disease (PD), especially the neurotrophic and inflammatory pathways regulated by CE, remains unknown. In this study, we investigated the anti-PD effects of CE in an MPTP-induced acute mouse model and its underlying mechanisms, focusing on BDNF, FGF2 and their mediated signaling pathways and RIP1-driven inflammatory signaling axis. Pole test and traction test were performed for behavioral analysis. RT-PCR, IHC and Western blotting were performed to assay the mRNA, tissues, and protein, respectively. We found that CE improved dyskinesia in MPTP-intoxicated mice, which was confirmed by the pole test and traction test. Also, oxidative stress and astrocyte activation and inflammation were alleviated. MPTP-intoxication disrupted the levels of BDNF, FGF2 and their mediated signaling pathways, triggered elevation of pro-inflammatory factors such as TNF-α, IL-1β, and IL-6, and activated RIP1-driven inflammatory axis. However, CE restored the levels of BDNF, FGF2 and TrkB/Akt signaling pathways while inhibiting the RIP1-driven inflammatory signaling axis, thereby inhibiting apoptosis, preventing loss of nigrostriatal neurons, and maintaining cellular homeostasis. Thus, CE is a promising agent for the treatment of PD. [ABSTRACT FROM AUTHOR]

The TANK-binding kinase 1 (TBK1) is a serine/threonine kinase belonging to the non-canonical inhibitor of nuclear factor-κB (IκB) kinase (IKK) family. TBK1 can be activated by pathogen-associated molecular patterns (PAMPs), inflammatory cytokines, and oncogenic kinases, including activated K-RAS/N-RAS mutants. TBK1 primarily mediates IRF3/7 activation and NF-κB signaling to regulate inflammatory cytokine production and the activation of innate immunity. TBK1 is also involved in the regulation of several other cellular activities, including autophagy, mitochondrial metabolism, and cellular proliferation. Although TBK1 mutations have not been reported in human cancers, aberrant TBK1 activation has been implicated in the oncogenesis of several types of cancer, including leukemia and solid tumors with KRAS-activating mutations. As such, TBK1 has been proposed to be a feasible target for pharmacological treatment of these types of cancer. Studies suggest that TBK1 inhibition suppresses cancer development not only by directly suppressing the proliferation and survival of cancer cells but also by activating antitumor T-cell immunity. Several small molecule inhibitors of TBK1 have been identified and interrogated. However, to this point, only momelotinib (MMB)/CYT387 has been evaluated as a cancer therapy in clinical trials, while amlexanox (AMX) has been evaluated clinically for treatment of type II diabetes, nonalcoholic fatty liver disease, and obesity. In this review, we summarize advances in research into TBK1 signaling pathways and regulation, as well as recent studies on TBK1 in cancer pathogenesis. We also discuss the potential molecular mechanisms of targeting TBK1 for cancer treatment. We hope that our effort can help to stimulate the development of novel strategies for targeting TBK1 signaling in future approaches to cancer therapy. [ABSTRACT FROM AUTHOR]

Background: Recently, TANK binding kinase 1 (TBK1) mutation has been reported as a causative gene for overlap frontotemporal dementia (FTD)‐amyotrophic lateral sclerosis (ALS) syndrome. However, there are no reports from families of South Asian ethnicity. Objective: To report a case study of a family with the proband having overlap FTD‐ALS syndrome caused by a novel TBK1 variant. Materials and methods: Clinical, brain imaging, genetic analysis and laboratory data of the patient with FTD‐ALS were performed. In addition, family‐based segregation analysis of identified novel variants was also done. Results: This study pertains to genetic analysis in 11 members in a family with only one member affected with overlap FTD‐ALS syndrome. The whole‐exome sequencing analysis in the symptomatic member showed a novel loss‐of‐function (LoF) variant c.1810G>T(p.E604X) in the TBK1 gene. Neuroimaging showed a pattern of asymmetric frontotemporal atrophy and hypometabolism. Segregation analysis of the variation demonstrated its presence in several family members, although none of the other members was symptomatic. Further, we observed another missense variation in the NEFH gene (p.Pro683Leu) which was seen in the symptomatic and two asymptomatic family members, the pathogenicity of which is unclear. Conclusion: This is the first study of a rare novel TBK1 variant associated with FTD‐ALS from India. Asymptomatic family members with the variant have important clinical implications and necessitate the genetic evaluation and long‐term follow‐up of family members of patients detected with TBK1 mutations. Therefore, although infrequent, genetic screening for the TBK1 gene should be considered when encountering overlap FTD syndromes. [ABSTRACT FROM AUTHOR]

Spleen tyrosine kinase (Syk) has recently come forth as a critical regulator of innate immune response. Previous studies identify Syk as a key kinase for STAT1 activation at the early stage of influenza A virus (IAV) infection that is involved in initial antiviral immunity. However, the involvement of Syk in host antiviral immunity during the late phase of IAV infection and its effect on pathogenesis of the virus remain unknown. Here, we found through time course studies that Syk restrained antiviral immune response at the late stage of IAV infection, thereby promoting viral replication. Depletion of Syk suppressed IAV replication in vitro, whereas ectopic expression of Syk facilitated viral replication. Moreover, Syk-deficient mice were employed, and we observed that knockout of Syk rendered mice more resistant to IAV infection, as evidenced by a lower degree of lung injury, slower body weight loss, and an increased survival rate of Syk knockout mice challenged with IAV. Furthermore, we revealed that Syk repressed the interferon response at the late stage of viral infection. Loss of Syk potentiated the expression of type I and III interferons in both Syk-depleted cells and mice. Mechanistically, Syk interacted with TBK1 and modulated its phosphorylation status, thereby impeding TBK1 activation and restraining innate immune signaling that governs interferon response. Together, these findings unveil a role of Syk in temporally regulating host antiviral immunity and advance our understanding of complicated mechanisms underlying regulation of innate immunity against viral invasion. IMPORTANCE Innate immunity must be tightly controlled to eliminate invading pathogens while avoiding autoimmune or inflammatory diseases. Syk is essential for STAT1 activation at the early stage of IAV infection, which is critical for initial antiviral responses. Surprisingly, here a time course study showed that Syk suppressed innate immunity during late phases of IAV infection and thereby promoted IAV replication. Syk deficiency enhanced the expression of type I and III interferons, inhibited IAV replication, and rendered mice more resistant to IAV infection. Syk impaired innate immune signaling through impeding TBK1 activation. These data reveal that Syk participates in the initiation of antiviral defense against IAV infection and simultaneously contributes to the restriction of innate immunity at the late stage of viral infection, suggesting that Syk serves a dual function in regulating antiviral responses. This finding provides new insights into complicated mechanisms underlying interaction between virus and host immune system. [ABSTRACT FROM AUTHOR]