Noncanonical NF-κB Signaling Pathway Research Articles

SHP-1 alleviates acute liver injury caused by Escherichia coli sepsis through negatively regulating the canonical and non-canonical NFκB signaling pathways

SHP-1, as a protein tyrosine phosphatase, plays a key role in inflammation-related diseases. However, its function and regulatory mechanism in the imbalance of inflammatory response and acute liver injury during sepsis are still unknown. Herein, we constructed a murine model of Escherichia coli (E. coli) sepsis and demonstrated the function and novel mechanism of SHP-1 in sepsis. Overexpression of SHP-1 significantly reduced the mortality rate of mice and alleviated the histopathological deterioration of liver. In addition, it inhibited the expression and release of pro-inflammatory mediators in liver tissue and serum, but upregulated the expression of anti-inflammatory molecules. Silencing SHP-1 exhibited the completely opposite effects. Furthermore, the transcriptome data of mice liver showed that SHP-1 suppressed the progression of sepsis by negatively regulating the activation of multiple inflammation-related signaling pathways. More importantly, we fully revealed the regulation mechanism of SHP-1 on both canonical and non-canonical nuclear factor kappa-B (NFκB) signaling pathways during sepsis for the first time. SHP-1 significantly inhibited the phosphorylation and nuclear translocation of p50, while p65 inhibition was mainly achieved by inhibiting its transcription and translation levels. Meanwhile, SHP-1 inhibited the phosphorylation and nuclear translocation of p52, thereby inhibiting the activation of non-canonical NFκB signaling pathways. In summary, SHP-1 negatively regulated canonical and non-canonical NFκB signaling pathways, thereby blocking the occurrence of excessive inflammatory response and acute liver injury caused by E. coli sepsis. Our findings systematically elucidate the role and mechanism of SHP-1 during sepsis, providing new insights into the prevention and treatment of inflammation and immune-related diseases.

Intra-amniotic delivery of tropomodulin 3 rescues cell apoptosis induced by miR-200b-3p upregulation via non-canonical nuclear factor kappa B pathways in ethylene thiourea induced anorectal malformations fetal rat

Ethylene thiourea (ETU), a metabolite of the fungicide ethylene bisdithiocarbamate (EBDC), has received great concern because of its harmful effects. ETU-induced anorectal malformations (ARMs) in rat models have been reported and widely used in the study of ARMs embryogenesis. Dysplasia of the lumbosacral spinal cord (LSSC), pelvic floor muscles (PFMs), and hindgut (HG) during intrauterine life affects postoperative defecation in patients with ARMs. However, the underlying toxic effects of ETU and pathological mechanisms in the three defecation-related tissues of fetuses with ARMs have not been reported. Thus, this study aimed to elucidate the molecular mechanisms involved in ARMs, with a focus on the dysregulation of miR-200b-3p and its downstream target tropomodulin 3 (TMOD3). The mRNA and protein levels of miR-200b-3p and TMOD3 in LSSC, PFMs, and HG of fetal rats with ARMs were evaluated by reverse transcription quantitative polymerase chain reaction and Western blotting (WB) on embryonic day 17 (E17). Further, a dual-luciferase reporter assay confirmed their targeting relationship. Gene silencing and overexpression of miR-200b-3p and TMOD3 were performed to verify their functions in HEK-293 T cells. Fetal rats with ARMs also received intra-amniotic microinjection of Ad-TMOD3 on E15, and key molecules in nuclear factor kappa (NF-κB) signaling and apoptosis were evaluated by WB on E21. Abnormally high levels of miR-200b-3p inhibited TMOD3 expression by binding with its 3′-untranslated region, leading to the activation of the non-canonical NF-κB signaling pathway, which is critical in the maldevelopment of LSSC, PFMs, and HG in ARMs rats. Furthermore, miR-200b-3p triggered apoptosis by directly targeting TMOD3. Notably, intra-amniotic Ad-TMOD3 microinjection revealed that the upregulation of TMOD3 expression mitigates the effects of miR-200b-3p on the activation of non-canonical NF-κB signaling and apoptosis in fetal rat model of ARMs. A novel miR-200b-3p/TMOD3/non-canonical NF-κB signaling axis triggered the massive apoptosis in LSSC, PFMs, and HG of ARMs, which was restored by the intra-amniotic injection of Ad-TMOD3 during embryogenesis. Our results indicate the potential of TMOD3 as a treatment target to restore defecation.

Lymphotoxin beta-activated LTBR/NIK/RELB axis drives proliferation in cholangiocarcinoma.

Cholangiocarcinoma (CCA) is an aggressive malignancy arising from the intrahepatic (iCCA) or extrahepatic (eCCA) bile ducts with poor prognosis and limited treatment options. Prior evidence highlighted a significant contribution of the non-canonical NF-κB signalling pathway in initiation and aggressiveness of different tumour types. Lymphotoxin-β (LTβ) stimulates the NF-κB-inducing kinase (NIK), resulting in the activation of the transcription factor RelB. However, the functional contribution of the non-canonical NF-κB signalling pathway via the LTβ/NIK/RelB axis in CCA carcinogenesis and progression has not been established. Human CCA-derived cell lines and organoids were examined to determine the expression of NF-κB pathway components upon activation or inhibition. Proliferation and cell death were analysed using real-time impedance measurement and flow cytometry. Immunoblot, qRT-PCR, RNA sequencing and insitu hybridization were employed to analyse gene and protein expression. Four invivo models of iCCA were used to probe the activation and regulation of the non-canonical NF-κB pathway. Exposure to LTα1/β2 activates the LTβ/NIK/RelB axis and promotes proliferation in CCA. Inhibition of NIK with the small molecule inhibitor B022 efficiently suppresses RelB expression in patient-derived CCA organoids and nuclear co-translocation of RelB and p52 stimulated by LTα1/β2 in CCA cell lines. In murine CCA, RelB expression is significantly increased and LTβ is the predominant ligand of the non-canonical NF-κB signalling pathway. Our study confirms that the non-canonical NF-κB axis LTβ/NIK/RelB drives cholangiocarcinogenesis and represents a candidate therapeutic target.

NCX1/Ca2+ promotes autophagy and decreases bortezomib activity in multiple myeloma through non-canonical NFκB signaling pathway

Although bortezomib (BTZ) is the cornerstone of anti-multiple myeloma (MM) therapy, the inevitable primary and secondary drug resistance still seriously affects the prognosis of patients. New treatment strategies are in need. Sodium-calcium exchanger 1 (NCX1) is a calcium-permeable ion transporter on the membrane, and our previous studies showed that low NCX1 confers inferior viability in MM cells and suppressed osteoclast differentiation. However, the effect of NCX1 on BTZ sensitivity of MM and its possible mechanism remain unclear. In this study, we investigated the effect of NCX1 on BTZ sensitivity in MM, focusing on cellular processes of autophagy and cell viability. Our results provide evidence that NCX1 expression correlates with MM disease progression and low NCX1 expression increases BTZ sensitivity. NCX1/Ca2+ triggered autophagic flux through non-canonical NFκB pathway in MM cells, leading to attenuated the sensitivity of BTZ. Knockdown or inhibition of NCX1 could potentiate the anti-MM activity of BTZ in vitro and vivo, and inhibition of autophagy sensitized NCX1-overexpressing MM cells to BTZ. In general, this work implicates NCX1 as a potential therapeutic target in MM with BTZ resistance and provides novel mechanistic insights into its vital role in combating BTZ resistance.

Not just for lymphoid cells: the role of the noncanonical NF-κB signaling pathway in early and late myelopoiesis with a focus on hypereosinophilic disorders.

The noncanonical NF-κB pathway is involved in lymphoid organ development, B-cell maturation, and cytokine production. However, new research has demonstrated that this pathway is also key for the orderly and sequential maturation of myeloid cells, including neutrophils and eosinophils. When this pathway is disrupted or constitutively activated, aberrations in hematopoietic stem and progenitor cell survival and proliferation, as well as subsequent granulopoiesis and eosinophilopoiesis, are affected. Disturbance of such a coordinated and delicate process can manifest in devastating clinical disease, including acute and chronic myeloid leukemias, preleukemic processes such as myelodysplastic syndrome, or hyperinflammatory conditions like hypereosinophilic syndrome. In this review, we discuss the molecular machinery within the noncanonical NF-κB pathway, crosstalk with the canonical NF-κB pathway, murine models of noncanonical signaling, and how aberrations in this pathway manifest in leukemic or hyperinflammatory disease with a focus on hypereosinophilic syndrome. Potential and promising drug therapies will also be discussed, emphasizing the noncanonical NF-κB pathway as a potential target for improved treatment for patients with leukemia or idiopathic hypereosinophilic syndrome. The hope is that review of such mechanisms and treatments may eventually result in findings that aid physicians in rapidly diagnosing and more accurately classifying patients with such complex and overlapping hematopoietic diseases.

The noncanonical NFκB pathway: Regulatory mechanisms in health and disease.

The noncanonical NFκB signaling pathway mediates the biological functions of diverse cell survival, growth, maturation, and differentiation factors that are important for the development and maintenance of hematopoietic cells and immune organs. Its dysregulation is associated with a number of immune pathologies and malignancies. Originally described as the signaling pathway that controls the NFκB family member RelB, we now know that noncanonical signaling also controls NFκB RelA and cRel. Here, we aim to clarify our understanding of the molecular network that mediates noncanonical NFκB signaling and review the human diseases that result from a deficient or hyper-active noncanonical NFκB pathway. It turns out that dysregulation of RelA and cRel, not RelB, is often implicated in mediating the resulting pathology. This article is categorized under: Immune System Diseases > Molecular and Cellular Physiology Cancer > Molecular and Cellular Physiology Immune System Diseases > Stem Cells and Development.

ANKRD22 promotes resolution of psoriasiform skin inflammation by antagonizing NIK-mediated IL-23 production

Inflammation resolution is an essential process for preventing the development of chronic inflammatory diseases. However, the mechanisms that regulate inflammation resolution in psoriasis are not well understood. Here, we report that ANKRD22 is an endogenous negative orchestrator of psoriasiform inflammation, as ANKRD22-deficient mice are more susceptible to IMQ-induced psoriasiform inflammation. Mechanistically, ANKRD22 deficiency leads to excessive activation of TNFRII-NIK-mediated noncanonical NF-κB signaling pathway, resulting in hyperproduction of IL-23 in DCs. This is due to ANKRD22 being a negative feedback regulator for NIK, as it physically binds to and assists in degradation of accumulated NIK. Clinically, ANKRD22 is negatively associated with IL23A expression and psoriasis severity. Of greater significance, subcutaneous administration of an AAV carrying ANKRD22-overexpression vector effectively hastens resolution of psoriasiform skin inflammation. Our findings suggest ANKRD22, an endogenous supervisor of NIK, is responsible for inflammation resolution in psoriasis, and may be explored in the context of psoriasiss therapy.

Dynamic modulation of the non-canonical NF-κB signaling pathway for HIV shock and kill.

HIV cure still remains an elusive target. The "Shock and Kill" strategy which aims to reactivate HIV from latently infected cells and subsequently kill them through virally induced apoptosis or immune mediated clearance, is the subject of widespread investigation. NF-κB is a ubiquitous transcription factor which serves as a point of confluence for a number of intracellular signaling pathways and is also a crucial regulator of HIV transcription. Due to its relatively lower side effect profile and proven role in HIV transcription, the non-canonical NF-κB pathway has emerged as an attractive target for HIV reactivation, as a first step towards eradication. A comprehensive review examining this pathway in the setting of HIV and its potential utility to cure efforts is currently lacking. This review aims to summarize non-canonical NF-κB signaling and the importance of this pathway in HIV shock-and-kill efforts.

Chlorogenic Acid Alleviated AFB1-Induced Hepatotoxicity by Regulating Mitochondrial Function, Activating Nrf2/HO-1, and Inhibiting Noncanonical NF-κB Signaling Pathway.

Aflatoxin B1 (AFB1), a kind of mycotoxin, imposes acute or chronic toxicity on humans and causes great public health concerns. Chlorogenic acid (CGA), a natural phenolic substance, shows a powerful antioxidant and anti-inflammatory effect. This study was conducted to investigate the effect and mechanism of CGA on alleviating cytotoxicity induced by AFB1 in L-02 cells. The results showed that CGA (160 μM) significantly recovered cell viability and cell membrane integrity in AFB1-treated (8 μM) cells. Furthermore, it was found that CGA reduced AFB1-induced oxidative injury by neutralizing reactive oxygen species (ROS) and activating the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway. In addition, CGA showed anti-inflammatory effects as it suppressed the expression of inflammation-related genes (IL-6, IL-8, and TNF-α) and AFB1-induced noncanonical nuclear factor kappa-B (NF-κB) activation. Moreover, CGA mitigated AFB1-induced apoptosis by maintaining the mitochondrial membrane potential (MMP) and inhibiting mRNA expressions of Caspase-3, Caspase-8, Bax, and Bax/Bcl-2. These findings revealed a possible mechanism: CGA prevents AFB1-induced cytotoxicity by maintaining mitochondrial membrane potential, activating Nrf2/HO-1, and inhibiting the noncanonical NF-κB signaling pathway, which may provide a new direction for the application of CGA.

IGF2BP1 Stabilizes and Inhibits Degradation of Pro-Oncogenic Transcripts in ETV6-RUNX1 Positive B-Cell Acute Lymphoblastic Leukemia

Insulin like growth factor 2 mRNA binding protein 1(IGF2BP1) belongs to a family of oncofetal proteins expressed in embryonic life followed by re-emergence during malignant transformation. It is an RNA binding protein known to be dysregulated and overexpressed in multiple malignancies. We have demonstrated its specific overexpression in ETV6-RUNX1 translocated B-cell Acute Lymphoblastic Leukemia (B-ALL). RNA immunoprecipitation using anti-IGF2BP1 antibody, followed by sequencing (RIP-Seq) in Reh cell line (ETV6-RUNX1 positive) identified multiple oncogenic transcripts belonging to the non-canonical NF-κB and PI3K signaling pathways. Overexpression of genes from these pathways (IL6ST, GADD45A, NFAT5, MDM2, CDK6, FGFR1) was also observed in our B-ALL patient samples specifically in the ETV6-RUNX1 positive patients (Total n=111; ETV6-RUNX1 positive: 39) in comparison to MACS sorted, peripheral blood CD19 positive B-cells from healthy volunteers as well as in comparison to non ETV6-RUNX1 translocated B-Acute lymphoblastic leukemia patients. This was also corroborated by public B-ALL gene expression data from the TARGET database in the cBioportal. However, knockout of IGF2BP1 in Reh cell line using CRISPR-Cas9 technology led to significant downregulation of only some of these targets. This implied that the expression of some of the mRNA targets binding to IGF2BP1 was not influenced by its knockout. To better elucidate the role played by IGF2BP1 in the stability of its binding mRNA targets, we decided to study the rate of degradation of target transcripts. mRNA stability was assessed to quantify the rate of degradation of target mRNA after inhibition of transcription using actinomycin. Since actinomycin causes global transcriptional block, we first quantified the effect of actinomycin on the expression of multiple (n=7) housekeeping genes against each other, and selected 3 ( HGPRT, B2M and PPIA) which showed least change after actinomycin treatment. These 3 housekeeping genes were used for further quantification of target transcripts. Dual specificity phosphatase 1( DUSP1) a transcript known to be rapidly degraded, was used to validate the transcriptional inhibition by actinomycin. We quantified the rate of degradation of target transcripts in Reh cells using BTYNB, a small molecule inhibitor of IGF2BP1. BTYNB binds to IGF2BP1 and prevents binding to target transcripts which leads to their destabilization and reduced half-life. We used a combination of BTYNB and actinomycin to study rate of degradation after IGF2BP1 inhibition. Effect of IGF2BP1 on the stability of three target mRNAs involved in non-canonical NF-κB signalling pathway was quantified by comparing their rate of degradation in BTYNB treated cells against the DMSO (vehicle) treated cells. Rate of degradation was measured by actinomycin treatment of both these groups followed by hourly RNA isolation and qPCR over 12 hours. MYC is a known mRNA binding target of IGF2BP1. BTYNB was also shown to decrease the expression of MYC mRNA by accelerating its degradation. Simultaneously there was an increase in the expression of MYC pre-mRNA indicating a possible for IGF2BP1 in splicing of MYC RNA. In the NF-κB signalling pathway, we had previously identified that NFAT5 expression was not altered significantly after IGF2BP1 knockout even though it binds to IGF2BP1. BTYNB followed by actinomycin treatment demonstrated a dramatic increase in the rate of degradation of NFAT5 implying that IGF2BP1 prevents the degradation of NFAT5 transcript and directly influences its stability. Interestingly, the rates of degradation of other targets like IL6ST and GADD45 were not altered. These findings suggest a heterogeneous influence of IGF2BP1 on the stability of its target transcripts. Some of the transcripts seem to be directly stabilised by IGF2BP1 while others may be influenced indirectly. Taken together, these findings suggest a role of IGF2BP1 in multiple phases of the RNA synthesis and degradation warranting further studies to elucidate role of IGF2BP1 in each of these steps. IGF2BP1 appears to have a critical role in preventing the degradation and stabilizing MYC and NFAT5 transcripts.

Interleukin-34-NF-κB signaling aggravates myocardial ischemic/reperfusion injury by facilitating macrophage recruitment and polarization

Macrophage infiltration and polarization are integral to the progression of heart failure and cardiac fibrosis after ischemia/reperfusion (IR). Interleukin 34 (IL-34) is an inflammatory regulator related to a series of autoimmune diseases. Whether IL-34 mediates inflammatory responses and contributes to cardiac remodeling and heart failure post-IR remains unclear. IL-34 knock-out mice were used to determine the role of IL-34 on cardiac remodeling after IR surgery. Then, immunofluorescence, flow cytometry assays, and RNA-seq analysis were performed to explore the underlying mechanisms of IL-34-induced macrophage recruitment and polarization, and further heart failure after IR. By re-analyzing single-cell RNA-seq and single-nucleus RNA-seq data of murine and human ischemic hearts, we showed that IL-34 expression was upregulated after IR. IL-34 knockout mitigated cardiac remodeling, cardiac dysfunction, and fibrosis after IR and vice versa. RNA-seq analysis revealed that IL-34 deletion correlated negatively with immune responses and chemotaxis after IR injury. Consistently, immunofluorescence and flow cytometry assays demonstrated that IL-34 deletion attenuated macrophage recruitment and CCR2+ macrophage polarization. Mechanistically, IL-34 deficiency repressed both the canonical and noncanonical NF-κB signaling pathway, leading to marked reduction of P-IKKβ and P-IκBα kinase levels; downregulation of NF-κB p65, RelB, and p52 expression, which drove the decline in chemokine CCL2 expression. Finally, IL-34 and CCL2 levels were increased in the serum of acute coronary syndrome patients, with a positive correlation between circulating IL-34 and CCL2 levels in clinical patients. In conclusion, IL-34 sustains NF-κB pathway activation to elicit increased CCL2 expression, which contributes to macrophage recruitment and polarization, and subsequently exacerbates cardiac remodeling and heart failure post-IR. Strategies targeting IL-34-centered immunomodulation may provide new therapeutic approaches to prevent and reverse cardiac remodeling and heart failure in clinical MI patients after percutaneous coronary intervention. This study was supported by the National Nature Science Foundation of China (81670352 and 81970327 to R T, 82000368 to Q F).

IRP1 mediated ferroptosis reverses temozolomide resistance in glioblastoma via affecting LCN2/FPN1 signaling axis depended on NFKB2

The prognosis of glioblastoma (GBM) patients is poor, and temozolomide (TMZ) resistance has become an important obstacle to its treatment effect. A growing number of researches have revealed the special characteristics of iron metabolism in GBM chemosensitivity. Iron regulatory protein 1 (IRP1) is an important protein for maintaining intracellular iron homeostasis. IRP1 has been indicated to have additional vital roles beyond its conventional metabolic activity, but the underlying mechanisms and biological consequences remain elusive. Here, we unprecedentedly demonstrated that amplifying IRP1 signals can reverse TMZ resistance and suppress tumor growth invivo via inhibiting NFKB2 in the noncanonical NF-κB signaling pathway. In addition, we identified that NFKB2 affected TMZ sensitivity of GBM by modulating the expression of LCN2 and FPN1. Taken together, this study established a role for the IRP1/NFKB2 pathway in regulating LCN2/FPN1 signaling axis among the progression of TMZ resistance, suggesting a potential innovative GBM therapeutic strategy.

Bioactive silica nanoparticles target autophagy, NF-κB, and MAPK pathways to inhibit osteoclastogenesis

Spherical 50 nm silica-based nanoparticles (SiNPs) promote healthy bone homeostasis and maintenance by supporting bone forming osteoblast lineage cells while simultaneously inhibiting the differentiation of bone resorbing osteoclasts. Previous work demonstrated that an intraperitoneal injection of SiNPs in healthy mice - both young and old - increased bone density and quality, suggesting the possibility that SiNPs represent a dual action therapeutic. However, the underlying mechanisms governing the osteoclast response to SiNPs have yet to be fully explored and defined. Therefore, the goals of this study were to investigate the cellular and molecular mechanisms by which SiNPs inhibit osteoclastogenesis. SiNPs strongly inhibited RANKL-induced osteoclast differentiation within the first hours and concomitantly inhibited early transcriptional regulators such as Nfatc1. SiNPs simultaneously stimulated expression of autophagy related genes p62 and LC3β dependent on ERK1/2 signaling pathway. Intriguingly, SiNPs were found to stimulate autophagosome formation while inhibiting the autophagic flux necessary for RANKL-stimulated osteoclast differentiation, resulting in the inhibition of both the canonical and non-canonical NF-κB signaling pathways and stabilizing TRAF3. These results suggest a model in which SiNPs inhibit osteoclastogenesis by inhibiting the autophagic machinery and RANKL-dependent functionality. This mechanism of action defines a novel therapeutic strategy for inhibiting osteoclastogenesis.

Proliferation, Plasticity, and Migration: Exploring the synergistic relationship between eosinophils and TH2 cells in development of HES-like syndrome

Abstract Aberrancies in eosinophil proliferation, activation and chemotaxis can lead to acute eosinophilic leukemia, paraneoplastic eosinophilia associated with T cell lymphoma and carcinomas, and Hypereosinophilic Syndrome (HES), respectively. HES is an idiopathic disease affecting humans and veterinary patients characterized by persistent eosinophilia (>1,500 cells/uL) and eosinophilic infiltration of solid organs leading to increased morbidity and mortality. Previous studies have demonstrated the role of NF-κB inducing kinase, NIK, an upstream regulator of the noncanonical NF-κB signaling pathway, in development of a HES-like syndrome due to aberrant TH2 polarization in the Nik−/−murine model. However, the intricacies of eosinophilic granulopoiesis, eosinophil/neutrophil plasticity, and chemotactic ability has not been assessed during development of HES-like syndrome in Nik−/−mice. Here we show that loss of NIK potentially enhances eosinophilic chemotaxis to CCL11, enhances eosinophilic/neutrophilic plasticity, and affects granulopoiesis in the bone marrow and spleen beginning at the level of eosinophilic metamyelocytes, despite potentially decreasing the proliferative potential of these cells. Taken together, these results suggest that NIK and the noncanonical NF-κB signaling pathway plays a role in dictating the hematopoietic and chemotactic potential of eosinophils and highlights a synergistic relationship with TH2 cells and their respective cytokines during development of HES-like syndrome in Nik−/−mice. Overall, these findings warrant further study to better characterize the synergistic relationship described above to better understand development of HES and HES-like diseases. Virginia-Maryland College of Veterinary Medicine and the Institute for Critical Technology and Applied Science

Inhibition of TANK-binding kinase1 attenuates the astrocyte-mediated neuroinflammatory response through YAP signaling after spinal cord injury.

TANK-binding kinase 1 (TBK1) is involved in regulating the pathological process of a variety of inflammatory diseases in the central nervous system. However, its role and underlying molecular mechanisms in spinal cord injury (SCI) remain largely unknown. We employed the TBK1 inhibitor amlexanox (ALX) to address this question. An in vivo clip-compressive SCI model and in vitro lipopolysaccharide (LPS)-induced astrocyte inflammation model were established to examine the effects of TBK1 inhibition on the expression of proinflammatory cytokines. In this study, we found that TBK1 and TBK1-medicated innate immune pathways, such as TBK1/IRF3 and noncanonical NF-κB signaling, were activated in astrocytes and neurons after SCI. Furthermore, inhibition of TBK1 by ALX alleviated neuroinflammation response, reduced the loss of motor neurons, and improved the functional recovery after SCI. Mechanistically, inhibition of TBK1 activity promoted the activation of the noncanonical NF-κB signaling pathway and inhibited p-IRF3 activity in LPS-induced astrocytes, and the TBK1 activity was required for astrocytic activation through yes-associated protein (YAP) signaling after SCI and in LPS-induced astrocytes inflammation model. TBK1-medicated innate immune pathway in astrocytes through YAP signaling plays an important role in the pathogenesis of SCI and inhibition of TBK1 may be a potential therapeutic drug for SCI.

A20 and the noncanonical NF-κB pathway are key regulators of neutrophil recruitment during fetal ontogeny.

Newborns are at high risk of developing neonatal sepsis, particularly if born prematurely. This has been linked to divergent requirements the immune system has to fulfill during intrauterine compared with extrauterine life. By transcriptomic analysis of fetal and adult neutrophils, we shed new light on the molecular mechanisms of neutrophil maturation and functional adaption during fetal ontogeny. We identified an accumulation of differentially regulated genes within the noncanonical NF-κB signaling pathway accompanied by constitutive nuclear localization of RelB and increased surface expression of TNF receptor type II in fetal neutrophils, as well as elevated levels of lymphotoxin α in fetal serum. Furthermore, we found strong upregulation of the negative inflammatory regulator A20 (Tnfaip3) in fetal neutrophils, which was accompanied by pronounced downregulation of the canonical NF-κB pathway. Functionally, overexpressing A20 in Hoxb8 cells led to reduced adhesion of these neutrophil-like cells in a flow chamber system. Conversely, mice with a neutrophil-specific A20 deletion displayed increased inflammation in vivo. Taken together, we have uncovered constitutive activation of the noncanonical NF-κB pathway with concomitant upregulation of A20 in fetal neutrophils. This offers perfect adaption of neutrophil function during intrauterine fetal life but also restricts appropriate immune responses particularly in prematurely born infants.

APOBEC3B Is Co-Expressed with PKCα/NF-κB in Oral and Oropharyngeal Squamous Cell Carcinomas.

The enzymatic activity of APOBEC3B (A3B) has been implicated as a prime source of mutagenesis in head and neck squamous cell carcinoma (HNSCC). The expression of Protein Kinase C α (PKCα) and Nuclear Factor-κΒ p65 (NF-κΒ p65) has been linked to the activation of the classical and the non-canonical NF-κB signaling pathways, respectively, both of which have been shown to lead to the upregulation of A3B. Accordingly, the aim of the present study was to evaluate the expression of PKCα, NF-κΒ p65 and A3B in non-HPV related oral and oropharyngeal squamous cell carcinomas (SCC), by means of immunohistochemistry and in silico methods. PKCα was expressed in 29/36 (80%) cases of oral and oropharyngeal SCCs, with 25 (69%) cases showing a PKCα+/A3B+ phenotype and only 6/36 (17%) cases showing a PKCα-/A3B+ phenotype. Εxpression of NF-κB p65 was seen in 33/35 (94%) cases of oral and oropharyngeal SCCs, with 30/35 (86%) cases showing an NF-κB p65+/A3B+ phenotype and only 2/35 (6%) cases showing an NF-κB p65-/A3B+ phenotype. In addition, mRNA expression analysis, using the UALCAN database, revealed strong expression of all three genes. These findings indicate that the expression of A3B is associated with PKCα/NF-κB p65 expression and suggest a potential role for the PKC/NF-κB signaling pathway in the development of oral and oropharyngeal cancer.

BAFF Promotes FLS Activation Through BAFFR-Mediated Non-canonical NF-κB Pathway and the Effects of CP-25.

B cell activating factor (BAFF) has been shown to play a key role in regulating B cell function, but little is known about whether BAFF affects the function of fibroblast-like synoviocyte (FLS), an effector cell of rheumatoid arthritis (RA). CP-25, a new ester derivative of paeoniflorin, could alleviate the arthritis symptoms of collagen-induced arthritis (CIA) mice by inhibiting BAFF-mediated abnormal activation of B cells. In this study, we aimed to understand the mechanism by which BAFF activates FLS and the effect of CP-25 on FLS function. Therefore, the proliferation and migration abilities of FLS and key proteins on the non-canonical NF-κB pathway were examined. The results showed that compared with the FLS of normal rats/OA patients, the expression of BAFF-R, TRAF2, NIK, p-IKKα, P100, and P52 was higher in the FLS of AA rats/RA patients, while the expression of TRAF3 was lower. And, BAFF promotes FLS activation by activating the non-canonical NF-κB signaling pathway. Meanwhile, BAFFR-siRNA inhibited the proliferation of FLS and the activation of non-canonical NF-κB signaling in FLS induced by BAFF. Additionally, CP-25 could inhibit abnormal proliferation and migration of FLS by regulating non-canonical NF-κBsignaling. We concluded that BAFF may act as an important role in facilitating the function of FLS through the BAFFR-mediated non-canonical NF-κB pathway, which would be useful for revealing the pathological mechanism of RA. And CP-25 may become a potential new drug for the treatment of RA, providing a scientific basis for the development of new drugs to treat RA.

TWEAK/FN14 promotes profibrogenic pathway activation in Prominin-1-expressing hepatic progenitor cells in biliary atresia.

Biliary atresia (BA), a congenital cholestatic liver disease, commonly culminates in end-stage liver disease. We previously demonstrated in BA that Prominin-1 ( Prom1 )-expressing hepatic progenitor cells (HPCs) expand within regions of developing fibrosis, giving rise to cholangiocytes within biliary ductular reactions. Null mutation of Prom1 or ablation of cells expressing Prom1 significantly diminishes fibrogenesis. FN14, the receptor for TNF-like weak inducer of apoptosis (TWEAK), is expressed by HPCs. TWEAK/FN14 signaling promotes fibrosis in multiple organ systems. Therefore, we hypothesized that TWEAK/FN14 signaling mediates Prom1 -expressing HPC proliferation leading to profibrogenic ductular reactions in BA. The experimental mouse model of BA mediated by perinatal rhesus rotavirus (RRV) infection resulted in increased co-expression of Fn14 in Prom1 -expressing HPCs within regions of ductular reactions. FN14 antagonist L524-0366 decreased ductular reactions, biliary fibrosis and periportal fibroblast activation in RRV injury. L524-0366 inhibition also demonstrated loss of downstream noncanonical NF-kB signaling expression in RRV injury. Murine HPC organoids demonstrated accelerated organoid growth and proliferation when treated with recombinant TWEAK. Increased organoid proliferation with recombinant TWEAK was lost when also treated with L524-0366. Analysis of a large publicly available RNA sequencing database of BA and normal control patients revealed significant increases in expression of PROM1 , FN14 , and genes downstream of TNF signaling and noncanonical NF-κB signaling pathways in BA infants. Infants who failed to achieve bile drainage after hepatoportoenterostomy had higher relative levels of FN14 expression. TWEAK/FN14 signaling activation in Prom1 -expressing HPCs contributes to proliferation of profibrogenic ductular reactions in BA.

Aggregated alpha-synuclein transcriptionally activates pro-inflammatory canonical and non-canonical NF-κB signaling pathways in peripheral monocytic cells

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by chronic neuroinflammation, loss of dopaminergic neurons in the substantia nigra, and in several cases accumulation of alpha-synuclein fibril (α-syn) containing Lewy-bodies (LBs). Peripheral inflammation may play a causal role in inducing and perpetuating neuroinflammation in PD and accumulation of fibrillar α-syn has been reported at several peripheral sites including the gut and liver. Peripheral fibrillar α-syn may induce activation of monocytes via recognition by toll-like receptors (TLRs) and stimulation of downstream NF-κB signaling; however, the specific mechanism by which this occurs is not defined. In this study we utilized the THP-1 monocytic cell line to model the peripheral transcriptional response to preformed fibrillar (PFF) α-syn. Compared to monomeric α-syn, PFF α-syn displays overt inflammatory gene upregulation and pathway activation including broad pan-TLR signaling pathway activation and increases in TNF and IL1B gene expression. Notably, the non-canonical NF-κB signaling pathway gene and PD genome wide association study (GWAS) candidate NFKB2 was upregulated. Additionally, non-canonical NF-κB activation-associated RANK and CD40 pathways were also upregulated. Transcriptional-phenotype analysis suggests PFFs induce transcriptional programs associated with differentiation of monocytes towards macrophages and osteoclasts via non-canonical NF-κB signaling as a potential mechanism in which myeloid/monocyte cells may contribute to peripheral inflammation and pathogenesis in PD.