Transducing signals from antigen receptors to nuclear factor kappaB

Q-switched 1064 nm Nd: YAG laser restores skin photoageing by activating autophagy by TGFβ1 and ITGB1

Excessive ultraviolet B ray (UVB) exposure to sunlight results in skin photoageing. Our previous research showed that a Q-switched 1064 nm Nd: YAG laser can alleviate skin barrier damage through miR-24-3p. However, the role of autophagy in the laser treatment of skin photoageing is still unclear. This study aims to investigate whether autophagy is involved in the mechanism of Q-switched 1064 nm Nd: YAG in the treatment of skin ageing. In vitro, primary human dermal fibroblast (HDF) cells were irradiated with different doses of UVB to establish a cell model of skin photoageing. In vivo, SKH-1 hairless mice were irradiated with UVB to establish a skin photoageing mouse model and irradiated with laser. The oxidative stress and autophagy levels were detected by western blot, immunofluorescence and flow cytometer. String was used to predict the interaction protein of TGF-β1, and CO-IP and GST-pull down were used to detect the binding relationship between TGFβ1 and ITGB1. In vitro, UVB irradiation reduced HDF cell viability, arrested cell cycle, induced cell senescence and oxidative stress compared with the control group. Laser treatment reversed cell viability, senescence and oxidative stress induced by UVB irradiation and activated autophagy. Autophagy agonists or inhibitors can enhance or attenuate the changes induced by laser treatment, respectively. In vivo, UVB irradiation caused hyperkeratosis, dermis destruction, collagen fibres reduction, increased cellular senescence and activation of oxidative stress in hairless mice. Laser treatment thinned the stratum corneum of skin tissue, increased collagen synthesis and autophagy in the dermis, and decreased the level of oxidative stress. Autophagy agonist rapamycin and autophagy inhibitor 3-methyladenine (3-MA) can enhance or attenuate the effects of laser treatment on the skin, respectively. Also, we identified a direct interaction between TGFB1 and ITGB1 and participated in laser irradiation-activated autophagy, thereby inhibiting UVB-mediated oxidative stress further reducing skin ageing. Q-switched 1064 nm Nd: YAG laser treatment inhibited UVB-induced oxidative stress and restored skin photoageing by activating autophagy, and TGFβ1 and ITGB1 directly incorporated and participated in this process.

Skin-Aging Pigmentation: Who Is the Real Enemy?

Skin aging is induced and sustained by chronological aging and photoaging. Aging skin pigmentation such as mottled pigmentation (senile lentigo) and melasma are typical signs of photoaging. The skin, like other human organs, undergoes cellular senescence, and senescent cells in the skin increase with age. The crosstalk between melanocytes as pigmentary cells and other adjacent types of aged skin cells such as senescent fibroblasts play a role in skin-aging pigmentation. In this review, we provide an overview of cellular senescence during the skin-aging process. The discussion also includes cellular senescence related to skin-aging pigmentation and the therapeutic potential of regulating the senescence process.

Carpelipines C and D, Two Anti-Inflammatory Germacranolides from the Flowers of Carpesium lipskyi Winkl. (Asteraceae)

Two new germacranolides, carpelipine C (1) and carpelipine D (2), together with four known ones (3-6), were isolated from Carpesium lipskyi Winkl. flowers, a folk Tibetan herbal medicine with antipyretic-analgesic and anti-inflammatory effects. The chemical structures of new structure were illuminated by diversified spectroscopic and X-ray crystallographic analyses. Compounds 1 and 3 dramatically suppressed the synthesis of NO and decreased pre-inflammatory protein expression of iNOS and COX-2 in LPS-induced RAW264.7 cells. Furthermore, it was revealed that NF-κB/MAPK signaling pathway were involved in the anti-inflammatory process of 1 and 3, and their effects on reducing oxidative stress by activating Nrf2/HO-1 pathway were also measured. This article indicated that the traditional use of C. lipskyi to treat inflammatory diseases has a certain rationality.

How Microbiomes Affect Skin Aging: The Updated Evidence and Current Perspectives

The skin has a multifactorial aging process, caused by both intrinsic and extrinsic factors. A major theory of aging involves cellular senescence or apoptosis resulting from oxidative damage as the skin’s antioxidant system tends to weaken with age. The human microbiota is a complex ecosystem that is made up of microorganisms (bacteria, fungi, and viruses). Both gut and skin microbiota have essential roles in the protection against invading pathogens, mediating inflammatory conditions, and the modulation of the immune system which is involved in both innate and adaptive immune responses. However, the human microbiome could be changed during the life stage and affected by various perturbations. An alteration of the intestinal bacteria results in “microbial dysbiosis” which is associated with the influence of various diseases, including aging. The skin interactome is a novel integration of the “genome-microbiome-exposome” that plays a significant role in skin aging and skin health. Mitigating the negative impacts of factors influencing the skin interactome should be the future strategy to protect, prevent, and delay skin aging along with preserving healthy skin conditions. This review summarizes the current evidence on how human microbiomes affect skin aging and demonstrates the possible interventions, relating to human microbiomes, to modulate skin health and aging. Probiotics-based products are currently available mainly for the add-on treatment of many dermatologic conditions. However, at this point, there are limited clinical studies on skin anti-aging purposes and more are required as this evolving concept is on the rise and might provide an insight into future therapeutic options.

Effect of boron element on photoaging in rats

BACKGROUND

The present study further assessed the effects of oral and topical applications of boron, which is known to have antiinflammatory and wound healing effects, on photoaging.

METHODS

A total of 49 eight-week-old female Wistar albino rats randomly divided into seven groups (control, shaved control, shaved+UVB, topical dermabor 2% (D2), and %5 (D5), systemic sodium perborate tetrahydrate (SPT) 2% (SPT2) and 4% (SPT4). To induce an experimental photoaging, the rats were exposed to UVB at an emission spectrum of 290-320 nm. Biochemical, molecular, skin, histological, and collagen content analyzes were made at the end of the study.

RESULTS

Increased skin inflammatory parameters (COX-2, IL-8, NF-KB, IL-6, and TNF-α) levels in UVB-exposed groups were inhibited in all treatment groups. The tissue level of hydroxyproline and elastase was found to decrease in all UVB-exposed group. The level of hydroxyproline was significantly higher in the D2 and D5 groups than in the SPT2 and SPT4 groups. The level of elastase was significantly lower in the D2 and D5 groups than in the SPT2 and SPT4 groups.

CONCLUSIONS

In future, boron may be developed as a functionally protective treatment against photoaging caused by UVB, and may be included in sun protection systems.

Photoprotective effect of Astragalus membranaceus polysaccharide on UVA-induced damage in HaCaT cells

Background

The skin provides a predominant barrier against chemical, physical and microbial incursion. The intemperate exposure to ultraviolet A (UVA) radiation can cause excessive cellular oxidative stress, leading to skin damage, proteins damage and mitochondrial dysfunction. There is sufficient evidences supporting the proposal that mitochondria is highly implicated in skin photo-damage.

Methods

In the present study, a polysaccharide isolated from Astragalus membranaceus was further purified to be an α-glucan, which was further investigated its beneficial influence on UVA-induced photo-damage in HaCaT cells.

Results

Our results showed that the purified Astragalus membranaceus polysaccharide (AP) can protect HaCaT cells from UVA-induced photo-damage through reducing UVA-induced intracellular ROS production and mitochondrial membrane potential, thereby altering ATP content. It was found that the UVA induced damage in HaCaT cells could be effectively restored by co-treatment with AP.

Conclusions

AP exhibited promising potential for advanced application as multifunctional skin care products and drugs.

Waterborne microcystin-LR exposure induced chronic inflammatory response via MyD88-dependent toll-like receptor signaling pathway in male zebrafish

Waterborne microcystin-LR (MC-LR) released by cyanobacterial blooms in eutrophic water bodies have caused serious risk to aquatic animal and human health. In the present study, we for the first time conducted a comprehensive in vivo investigation on chronic inflammatory responses and its molecular pathways of different environmental relevant levels of MC-LR (0, 0.4, 2 and 10 μg/L) in male zebrafish (Danio rerio). The results showed that chronic MC-LR exposure caused splenic inflammatory changes including the formation of melano-macrophage centers, remarkable elevation of serum tumor necrosis factor alpha (TNFα) and interleukin 1 beta (IL1β) levels as well as significant upregulated expression of MyD88-dependent toll-like receptor (TLR/MyD88) signaling pathway genes (tlr4a, myd88, erk2, p38a, il1β and tnfα). The immunohistochemical and western blot results further validated that higher MC-LR concentrations tended to enhance the MyD88 signal. Moreover, significant decreases of serum C3 levels along with splenic c3b expression in the 10 μg/L exposure group proved that chronic MC-LR exposure could ultimately decrease the innate immunity of fish. Our findings revealed that chronic exposure of MC-LR could cause chronic inflammation through TLR/MyD88 signaling pathway and subsequently induce immune disorders in male zebrafish, which also urge us to pay more attention on the potential immunotoxicity of long-term exposure to low concentration of MC-LR.

Protective Effect of the Total Triterpenes of Euscaphis konishii Hayata Pericarp on Bacillus Calmette-Guérin Plus Lipopolysaccharide-Induced Liver Injury

BACKGROUND

Liver injury has been recognized as a primary cause of hepatic morbidity and mortality. Euscaphis konishii Hayata, also called Euscaphis fukienensis Hsu, is usually used as a detumescent and analgesic agent to improve liver function in South China, but its mechanism of action and chemical composition are unclear.

OBJECTIVE

The main aim of the study was to investigate the constituent and potential hepatoprotective mechanism of the total triterpenes of E. konishii pericarp (TTEP).

METHODS

The constituent of TTEP was analyzed by a series of silica gel column to get single compounds and then identified by NMR and MS. In vitro assays were conducted to test the free radical scavenging activity of TTEP. The BCG/LPS-induced immunological livery injury mice model was established to clarify the hepatoprotective effect of TTEP in vivo.

RESULTS

8 pentacyclic triterpene acids were separated and identified by NMR and MS. TTEP treatment (50, 100, and 200 mg/Kg) improved the immune function of the BCG/LPS-infected mice, dose-dependently alleviated the BCG/LPS-induced inflammation and oxidative stress, and ameliorated the hepatocyte apoptosis in the liver tissue.

CONCLUSION

The pericarp of E. konishii may be further considered as a potent natural food for liver disease treatment.

Asiatic acid attenuates lipopolysaccharide-induced injury by suppressing activation of the Notch signaling pathway

Sepsis is a severe multisystem disease with high mortality rates and limited treatment options. However, advances during the last decade have opened opportunities to develop novel therapeutic strategies. The Notch signaling pathway plays a critical role in inflammation, and its inhibition offers an avenue to treat inflammatory diseases, such as sepsis. Asiatic acid (AA), a triterpenoid isolated from Centella asiatica, reportedly exerts anti-oxidant, anti-tumor, and anti-inflammatory effects, but its mechanisms remain unclear. In our study, we found that AA decreased levels of interleukin-1β (IL-1β), IL-6, alanine aminotransferase and blood urea nitrogen in serum; attenuated liver, lung and kidney damage; and improved the survival among mice with experimental sepsis. AA also reduced lipopolysaccharide-stimulated expression of proinflammatory mediators, including nitric oxide, IL-1β and IL-6 in RAW 264.7 macrophages. Notably, we demonstrated for the first time that AA is a novel small molecule inhibitor of the Notch signaling pathway. Its effects include upregulation of Notch receptor (Notch3) and delta-like ligand (DLL4), inhibition of Notch3 binding to the IL-6 promoter and regulation of mitochondrial function. These novel effects of AA may provide new approaches and strategies for the treatment of inflammatory disorders.

B-cell signaling in persistent polyclonal B lymphocytosis (PPBL)

Persistent polyclonal B lymphocytosis (PPBL) is a benign hematological disorder characterized by a selective expansion of circulating polyclonal marginal zone (MZ)-like B cells. Previous reports demonstrated that cases of PPBL showed poor activation, proliferation and survival of B cells in vitro, yet the underlying defect remains unknown. Here we report for the first time an attenuated activation of the canonical NF-κB (nuclear factor of kappa light polypeptide gene enhancer in B cells) and mitogen-activated protein kinase/extracellular signal-regulated kinase pathway after CD40 stimulation. This defect was selective, as alternative NF-κB signaling after CD40 stimulation and both B-cell receptor- and Toll-like receptor 9-mediated activation remained unaffected. Reduced canonical NF-κB activation resulted in decreased IκBα and CD40 expression in resting cells. In PPBL patients, expression of Bcl-xL in MZ-like B cells did not increase upon activation, consistent with the high apoptosis rates of PPBL-derived B cells that were observed in vitro. The B-cell phenotype of mice with selective knockouts of early components of the CD40 signaling pathway resembles PPBL, but sequencing corresponding genes in sorted MZ-like B cells of PPBL patients did not reveal relevant genetic alterations. Nevertheless, the frequently observed mutations in early signaling components of the NF-κB pathway in MZ lymphomas underline the relevance of our findings for the pathogenesis of PPBL.

NF-κB-inducing kinase is essential for B-cell maintenance in mice

NF-κB-inducing kinase (NIK) is a key mediator of the noncanonical NF-κB signaling pathway, which is critical for normal B-cell development and function. It is well established that the complete deletion of NIK in mice results in defective B cells and impaired secondary lymphoid organogenesis. To address the role of NIK deficiency specifically in B cells, we generated a new mouse strain for the conditional deletion of this kinase. Deletion of NIK during B-cell development results in a drastic reduction of mature B cells from the transitional 2 stage on, while B-1 B cells are less affected. Moreover, deletion of NIK in the germinal centers decreases the numbers of germinal center B cells and impairs the ability of NIK-deficient B cells to develop into class-switched cells in vivo. This new mouse strain will be helpful for studying the role of NIK in different cell types of the body.

Group A Streptococcus induces less p65 nuclear translocation and non-classical nuclear factor kappa B activation in macrophages, which possibly leads to a weaker inflammatory response

OBJECTIVES

The aim of this study was to explore the pathogenic mechanism of group A Streptococcus (GAS) and to investigate how GAS evades phagocytosis by immune cells.

METHODS

The classical inflammatory signaling pathway of macrophages infected with GAS was investigated by protein microarray, real-time PCR, Western blot, immunoprecipitation, and flow cytometry.

RESULTS

GAS induced a lower level of inflammatory mediators in macrophages than either the Gram-positive Staphylococcus aureus or the Gram-negative Escherichia coli. Therefore, the conventional inflammatory signal pathway was investigated. It was found that GAS and S. aureus induced both toll-like receptor (TLR)2 and TLR4 expression, while Gram-negative E. coli only activated TLR4 in RAW264.7 cells. Although MyD88, the main adaptor protein, was activated by the three pathogens, there was no difference in MyD88 expression in macrophages. Nuclear factor kappa B (NF-κB) is the classical transcription factor of inflammatory signals, and the results of the present study showed that GAS, similar to E. coli, induced a weaker p65 nuclear translocation compared to S. aureus. Interestingly, GAS activated NF-κB by inducing p65-p52 heterodimer, but not the classical heterodimer of NF-κB (p65-p50), while E. coli activated NF-κB by inducing both p65-p50 and p65-p52 heterodimers.

CONCLUSIONS

Compared to S. aureus and E. coli infection, GAS induced a weaker nuclear translocation and distinct combination of NF-κB subunits in macrophages, which probably leads to a weak inflammatory response.

Antibacterial and Anti-Inflammatory Activities of Physalis Alkekengi var. franchetii and Its Main Constituents

This study was designed to determine whether the 50% EtOH fraction from AB-8 macroporous resin fractionation of a 70% EtOH extract of P. Alkekengi (50-EFP) has antibacterial and/or anti-inflammatory activity both in vivo and in vitro and to investigate the mechanism of 50-EFP anti-inflammatory activity. Additionally, this study sought to define the chemical composition of 50-EFP. Results indicated that 50-EFP showed significant antibacterial activity in vitro and efficacy in vivo. Moreover, 50-EFP significantly reduced nitric oxide (NO), prostaglandin E₂ (PGE₂), tumor necrosis factor alpha (TNF-α), interleukin 1 (IL-1), and interleukin 6 (IL-6) production in lipopolysaccharide- (LPS-) stimulated THP-1 cells. Nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) (examined at the protein level) in THP-1 cells were suppressed by 50-EFP, which inhibited nuclear translocation of p65. Consistent with this anti-inflammatory activity in vitro, 50-EFP reduced inflammation in both animal models. Finally, seventeen compounds (8 physalins and 9 flavones) were isolated as major components of 50-EFP. Our data demonstrate that 50-EFP has antibacterial and anti-inflammatory activities both in vitro and in vivo. The anti-inflammatory effect appears to occur, at least in part, through the inhibition of nuclear translocation of p65. Moreover, physalins and flavones are probably the active components in 50-EFP that exert antibacterial and anti-inflammatory activities.

Differential Inhibition of T Lymphocyte Proliferation and Cytokine Synthesis by [6]-Gingerol, [8]-Gingerol, and [10]-Gingerol

[6]-Gingerol, [8]-gingerol, and [10]-gingerol are pungent components of fresh ginger, extracts of which inhibit various components of the inflammatory response. Because little is known regarding the effect of gingerols with different unbranched alkyl side chain lengths on the activation and effector function of T lymphocytes, we compared the effects of [6]-gingerol, [8]-gingerol, and [10]-gingerol on murine T lymphocyte proliferation, expression of CD25 and CD69 activation markers, cytokine synthesis, and interleukin (IL)-2 receptor signaling. All three gingerols inhibited DNA synthesis by T lymphocytes, as well as interferon-γ synthesis. In contrast, only [8]-gingerol and [10]-gingerol inhibited CD25 and CD69 expression, and IL-2 synthesis. None of the gingerols affected IL-4 synthesis. Exogenous IL-2 enhanced T lymphocyte proliferation in the presence of [6]-gingerol but did not significantly increase T lymphocyte proliferation in the presence of [8]-gingerol or [10]-gingerol. In line with this finding, [8]-gingerol and [10]-gingerol impaired IL-2-induced proliferation of CTLL-2 cells, but constitutive CD25 expression was unaffected, indicating inhibition of IL-2 receptor signaling. In general, [10]-gingerol and [8]-gingerol were more potent inhibitors of T lymphocytes than [6]-gingerol. Suppression of T lymphocyte responses by gingerols suggests that these phytochemicals may be beneficial in chronic inflammatory conditions associated with excessive or inappropriate T lymphocyte activation.

Pentacyclic Triterpenoids Inhibit IKKβ Mediated Activation of NF-κB Pathway: In Silico and In Vitro Evidences

Pentacyclic Triterpenoids (PTs) and their analogues as well as derivatives are emerging as important drug leads for various diseases. They act through a variety of mechanisms and a majority of them inhibit the nuclear factor kappa-beta (NF-κB) signaling pathway. In this study, we examined the effects of the naturally occurring PTs on IκB kinase-β (IKKβ), which has great scientific relevance in the NF-κB signaling pathway. On virtual screening, 109 PTs were screened through the PASS (prediction of activity spectra of substances) software for prediction of NF-κB inhibitory activity followed by docking on the NEMO/IKKβ association complex (PDB: 3BRV) and testing for compliance with the softened Lipinski’s Rule of Five using Schrodinger (LLC, New York, USA). Out of the projected 45 druggable PTs, Corosolic Acid (CA), Asiatic Acid (AA) and Ursolic Acid (UA) were assayed for IKKβ kinase activity in the cell free medium. The UA exhibited a potent IKKβ inhibitory effect on the hotspot kinase assay with IC50 of 69 μM. Whereas, CA at 50 μM concentration markedly reduced the NF-κB luciferase activity and phospho-IKKβ protein expressions. The PTs tested, attenuated the expression of the NF-κB cascade proteins in the LPS-stimulated RAW 264.7 cells, prevented the phosphorylation of the IKKα/β and blocked the activation of the Interferon-gamma (IFN-γ). The results suggest that the IKKβ inhibition is the major mechanism of the PTs-induced NF-κB inhibition. PASS predictions along with in-silico docking against the NEMO/IKKβ can be successfully applied in the selection of the prospective NF-κB inhibitory downregulators of IKKβ phosphorylation.

Combined immunodeficiency due to MALT1 mutations, treated by hematopoietic cell transplantation

Purpose

A male infant developed generalized rash, intestinal inflammation and severe infections including persistent cytomegalovirus. Family history was negative, T cell receptor excision circles were normal, and engraftment of maternal cells was absent. No defects were found in multiple genes associated with severe combined immunodeficiency. A 9/10 HLA matched unrelated hematopoietic cell transplant (HCT) led to mixed chimerism with clinical resolution. We sought an underlying cause for this patient’s immune deficiency and dysregulation.

Methods

Clinical and laboratory features were reviewed. Whole exome sequencing and analysis of genomic DNA from the patient, parents and 2 unaffected siblings was performed, revealing 2 MALT1 variants. With a host-specific HLA-C antibody, we assessed MALT1 expression and function in the patient’s post-HCT autologous and donor lymphocytes. Wild type MALT1 cDNA was added to transformed autologous patient B cells to assess functional correction.

Results

The patient had compound heterozygous DNA variants affecting exon 10 of MALT1 (isoform a, NM_006785.3), a maternally inherited splice acceptor c.1019-2A > G, and a de novo deletion of c.1059C leading to a frameshift and premature termination. Autologous lymphocytes failed to express MALT1 and lacked NF-κB signaling dependent upon the CARMA1, BCL-10 and MALT1 signalosome. Transduction with wild type MALT1 cDNA corrected the observed defects.

Conclusions

Our nonconsanguineous patient with early onset profound combined immunodeficiency and immune dysregulation due to compound heterozygous MALT1 mutations extends the clinical and immunologic phenotype reported in 2 prior families. Clinical cure was achieved with mixed chimerism after nonmyeloablative conditioning and HCT.

Electronic supplementary material

The online version of this article (doi:10.1007/s10875-014-0125-1) contains supplementary material, which is available to authorized users.

Mechanisms and treatments of photoaging

Photoaging is frequently encountered in a dermatologic practice. This systematic literature review aims to explore the etiology of photoaging and address the evidence behind its current management. A comprehensive search of MEDLINE, EMBASE, UpToDate, and the Cochrane Library was conducted. Articles were limited to those relating to photoaging. There are two major approaches in the current management of photoaging. This includes strategies to prevent against ultraviolet damage (e.g. sunscreen) and medications that attempt to reverse existing skin damage (topical retinoids and 5-fluorouracil). There has been a large growth in the variety of treatment options in recent years. While it is important for such growth to continue, prevention via sensible photoprotection methods still remains the best current management option.

Skin photoageing: mechanisms of development and particular features of clinical manifestations

The article discloses current concepts of mechanisms of development of skin photoageing caused by UV irradiation (UVA and UVB). Chronic exposure of skin to UV irradiation results in damage of genome DNA, development of DNA mutations, damage of proteins, membrane lipids, collagen and yellow fibers, degradation of the intercellular substance of the skin, development of a chronic inflammation, immunosuppression, melanogenesis disorders and increased angiogenesis. The authors described major clinical manifestations of skin photoageing and their histological characteristics.

Combined immune deficiency in a patient with a novel NFKB2 mutation

NFKB2 encodes the p100/p52 protein, a critical mediator of the canonical and noncanonical NFkB signaling pathways. Here we report the comprehensive immune evaluation of a child with a novel NFKB2 mutation and provide evidence that aberrant NFKB2 signaling not only causes humoral immune deficiency, but also interferes with the TCR-mediated proliferation of T cells. These observations expand the known phenotype associated with NFKB2 mutations.

Interleukin-1 receptor-associated kinase-2 genetic variant rs708035 increases NF-κB activity through promoting TRAF6 ubiquitination

The IL-1 receptor-associated kinases (IRAKs) are key regulators of Toll-like receptor (TLR)/IL-1 signaling, which are critical regulators of mammalian inflammation and innate immune response. Single nucleotide polymorphisms (SNPs) within the IRAK genes have been discovered recently. However, the functions of these IRAK SNPs remain largely unknown. Here, we found that the non-synonymous IRAK2 variant rs708035 (coding D431E) increases NF-κB activity and leads to more expression of NF-κB-dependent proinflammatory cytokines compared with IRAK2 wild type. Moreover, when IRAK2 knockdown cells reconstituted with siRNA-resistant WT-IRAK2 or D431E-IRAK2 were infected with influenza virus, a more obvious induction of IL-6 and a stronger anti-apoptosis effect were observed in D431E-IRAK2 expressing cells. Notably, we also found that the levels of proinflammatory cytokine-IL-6 were indeed higher in people carrying D431E-IRAK2 than those carrying WT-IRAK2. Further study demonstrated that elevated NF-κB activation mediated by the IRAK2 variant was due to increased TRAF6 ubiquitination and faster IκBα degradation. Our study provides important insight of IRAK2 SNP in the regulation of NF-κB activation and indicates that IRAK2 rs708035 might be associated with human diseases caused by hyper-activation of NF-κB.

Role of spleen tyrosine kinase in the pathogenesis of chronic lymphocytic leukemia

The antigen-dependent B-cell receptor (BCR) is triggered by binding to external antigens and transmits signals in normal B lymphocytes. Tonic signaling through the BCR plays a crucial role in the pathogenesis and progression of chronic lymphocytic leukemia (CLL). Spleen tyrosine kinase (Syk) is a key component of both BCR signals, and regulates multiple physiological functions of B lymphocytes. Studies have defined enhanced gene expression and protein expression of Syk in CLL cells which are closely related to the status of the immunoglobulin heavy chain variable region genes (IgVH). Recently, abrogating the BCR-induced signaling pathway by Syk inhibitors has represented a novel and active therapeutic approach for CLL. Studies of the correlation between Syk and ZAP-70 expression in CLL cells have brought a new perspective to determining the value of Syk in evaluating the effect of therapy and the prognosis of CLL. Therefore, we here review the role of Syk in the pathogenesis of CLL and provide an update of progress in the clinical development of Syk inhibitors.

Protective effects of the SEPS1 gene on lipopolysaccharide-induced sepsis

Septic shock and sequential multiple organ failure are the main cause of mortality in patients with sepsis. The induction of inflammation during sepsis is a complex biological cascade, which requires successful therapeutic intervention. Selenoprotein S (SEPS1) is a novel endoplasmic reticulum-resident protein and is important in the production of inflammatory cytokines. The present study attempted to assess the effect of SEPS1 suppression by small interfering RNA (siRNA) on mice with lipopolysaccharide (LPS)-induced sepsis. In total, 30 mice were randomly assigned to three groups: i) H group (LPS-induced sepsis group; n=10): Mice with intraperitoneal injection of LPS (10 mg/kg); ii) K group (scrambled siRNA group; n=10): Mice transfected with scrambled control siRNA 12 h prior to injection with LPS and iii) L group (SEPS1 siRNA group; n=10): Mice transfected with SEPS1 siRNA 12 h prior to injection with LPS. The effects of siRNA were evaluated by SEPS1 gene and protein expression, biochemical parameters including serum alanine transaminase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), lactic dehydrogenase (LDH), creatine kinase (CK) and myocardial kinase (CK-MB), as well as the cytokines interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). The phosphorylation of p38 mitogen-activated protein kinases (p38 MAPK) was also detected by western blot analysis. In the SEPS1 siRNA group, SEPS1 gene and protein expression decreased significantly, while the levels of TNF-α and IL-6 increased compared with the control group. The biochemical parameters of ALT, AST, BUN, LDH, CK and CK-MB were markedly increased in the SEPS1 siRNA group. The phosphorylation of p38 MAPK was also significantly activated. The decrease in SEPS1 gene and protein expression and the production of TNF-α and IL-6 may correlate with the activation of the p38 MAPK pathway. Biochemical factors and pathological results demonstrated that the damage to vital organs was aggravated. In conclusion, these findings suggested that SEPS1 may protect mice against LPS-induced sepsis and organ damage. Therefore, SEPS1 may be a new target to resolve LPS-induced sepsis.

Combined immunodeficiencies with nonfunctional T lymphocytes

Immunodeficiencies with nonfunctional T cells comprise a heterogeneous group of conditions characterized by altered function of T lymphocytes in spite of largely preserved T cell development. Some of these forms are due to hypomorphic mutations in genes causing severe combined immunodeficiency. More recently, advances in human genome sequencing have facilitated the identification of novel genetic defects that do not affect T cell development, but alter T cell function and homeostasis. Along with increased susceptibility to infections, these conditions are characterized by autoimmunity and higher risk of malignancies. The study of these diseases, and of corresponding animal models, has provided fundamental insights on the mechanisms that govern immune homeostasis.

Role of diacylglycerol kinases in T cell development and function

Diacylglycerol (DAG), a second messenger generated by phospholipase Cγ1 activity upon engagement of a T-cell receptor, triggers several signaling cascades that play important roles in T cell development and function. A family of enzymes called DAG kinases (DGKs) catalyzes the phosphorylation of DAG to phosphatidic acid, acting as a braking mechanism that terminates DAG-mediated signals. Two DGK isoforms, α and ζ, are expressed predominantly in T cells and synergistically regulate the development of both conventional αβ T cells and invariant natural killer T cells in the thymus. In mature T cells, the activity of these DGK isoforms aids in the maintenance of self-tolerance by preventing T-cell hyperactivation upon T cell receptor stimulation and by promoting T-cell anergy. In CD8 cells, reduced DGK activity is associated with enhanced primary responses against viruses and tumors. Recent work also has established an important role for DGK activity at the immune synapse and identified partners that modulate DGK function. In addition, emerging evidence points to previously unappreciated roles for DGK function in directional secretion and T-cell adhesion. This review describes the multitude of roles played by DGKs in T cell development and function and emphasizes recent advances in the field.

Diacylglycerol kinase ζ limits B cell antigen receptor-dependent activation of ERK signaling to inhibit early antibody responses

Signaling downstream of the B cell antigen receptor (BCR) is tightly regulated to enable cells to gauge the strength and duration of antigen-receptor interactions and to respond appropriately. We investigated whether metabolism of the second messenger diacylglycerol (DAG) by members of the family of DAG kinases (DGKs) played a role in modulating the magnitude of signaling by DAG downstream of the BCR. In the absence of DGKζ, the threshold for BCR signaling, measured as activation of the Ras-extracellular signal-regulated kinase (ERK) pathway, was markedly reduced in mature follicular B cells, which resulted in enhanced responses to antigen in vitro and in vivo. Inhibition of DAG signaling by DGKζ limited the number of antibody-secreting cells that were generated early in response to T cell-independent type 2 antigens, as well as to T cell-dependent antigens. Furthermore, the effect of loss of DGKζ closely resembled the effect of increasing the affinity of the BCR for antigen during the T cell-dependent antibody response. These results suggest that the magnitude of DAG signaling is important for translating the affinity of the BCR for antigen into the amount of antibody produced during the early stages of an immune response.

Moringa Fruit Inhibits LPS-Induced NO/iNOS Expression through Suppressing the NF-κB Activation in RAW264.7 Cells

In this study, we evaluated the anti-inflammatory effects of moringa (Moringa oleifera Lam.), a natural biologically active substance, by determining its inhibitory effects on pro-inflammatory mediators in lipopolysaccharide (LPS)-stimulated macrophage RAW264.7 cells. Extracts from different parts of moringa (root, leaf, and fruit) reduced LPS-induced nitric oxide (NO) release in a dose-dependent manner. The moringa fruit extract most effectively inhibited LPS-induced NO production and levels of inducible nitric oxide synthase (iNOS). The moringa fruit extract also was shown to suppress the production of inflammatory cytokines including IL-1β, TNF-α, and IL-6. Furthermore, moringa fruit extract inhibited the cytoplasmic degradation of I κ B -α and the nuclear translocation of p65 proteins, resulting in lower levels of NF -κ B transactivation. Collectively, the results of this study demonstrate that moringa fruit extract reduces the levels of pro-inflammatory mediators including NO , IL-1β, TNF-α, and IL-6 via the inhibition of NF -κ B activation in RAW264.7 cells. These findings reveal, in part, the molecular basis underlying the anti-inflammatory properties of moringa fruit extract.

Identification and characterization of a novel IκB-ε-like gene from lamprey (Lampetra japonica) with a role in immune response

Nuclear factor of kappa B (NF-κB) is a stimuli-activated transcription factor, regulates the expression of a diverse array of genes. Inhibitor of kappa B-epsilon (IκB-ε) is an inhibitor of NF-κB, which retains NF-κB in an inactive state in the cytoplasm. Lampreys (Lampetra japonica) belong to the lowest class of vertebrates with little information about its IκBs. We have identified a cDNA sequence IκB-ε-like in the lamprey and the deduced amino acid sequence of IκB-ε-like. It contains a conserved DSGxxS motif and six consecutive ankyrin repeats, which are necessary for signal-induced degradation of the molecule. Phylogenetic analysis indicated it had high sequence homology with IκB-εs from other vertebrates. FACS analysis showed that IκB-ε-like located in cytoplasm of leukocytes. The degradation of IκB-ε-like could be observed in leukocytes of L. japonica stimulated with lipopolysaccharide. These results indicate that IκB-ε proteins are conserved across vertebrates and the NF-κB-like signaling pathway may exist in the oldest agnatha.

Correlation between expression of CARMA1 and NF-κB proteins in common subtypes of gastrointestinal B cell lymphoma

AIM: To investigate the relationship between the expression of CARMA1 and nuclear factor κB (NF-κB) proteins in common subtypes of gastrointestinal B cell lymphoma.

METHODS: Fifty-four specimens of lymphomas, including 34 cases of diffuse large B-cell lymphoma (DLBCL) and 20 cases of mucosa-associated lymphoid tissue (MALT) lymphoma, and 21 specimens of gastrointestinal reactive lymphoid hyperplasia (GRLH) were selected for H&E staining and immunohistochemical staining. The mRNA and protein expression of CARMA1 was detected by Real-time PCR and immunohistochemistry, respectively. Expression of NF-κB proteins was assayed by immunohistochemistry.

RESULTS: The positive rates of CARMA1, NF-κB/p65 and NF-κB/p50 proteins were significantly higher in lymphomas than in GRLH (75.9% vs 47.6%, 48.2% vs 14.3%, 38.9% vs 9.5%; P = 0.042, 0.007, 0.013). The expression levels of CARMA1 mRNA and protein were significantly higher in DLBCL than in MALT lymphoma (P = 0.019, 0.020). There were significant differences in CARMA1 protein expression between lymphomas which were positive and negative for NF-κB/p65 or NF-κB/p50 (84.6% vs 67.9%, 71.4% vs 78.8%, P = 0.030, 0.031). CARMA1 mRNA expression was significantly higher in advanced cases than in early disease (P = 0.011). Expression of CARMA1 protein was significantly higher in cases which infiltrated through the wall than in those which did not (91.7% vs 66.7%, P = 0.003). The levels of CARMA1 mRNA and protein were significantly higher in cases with a high proliferation rate (P = 0.035, 0.006). Expression of NF-κB/p65 and NF-κB/p50 proteins was obviously increased in cases with a later TNM stage or a high proliferation rate (P = 0.015, 0.05, 0.018, 0.001). The type of lymphoma, stage, CARMA1 and NF-κB/p65 protein expression were independent factors affecting the prognosis of lymphomas. Survival was poor in cases with strong expression of CARMA1 protein than in those without (P = 0.02).

CONCLUSION: Expression of CARMA1 was correlated with that of NF-κB in gastrointestinal MALT lymphoma and DLBCL. CARMA1 expression may induce activation of NF-κB and thereby participate in the pathogenesis and progression of gastrointestinal MALT lymphoma and DLBCL.

Polysaccharide from Ganoderma atrum evokes antitumor activity via Toll-like receptor 4-mediated NF-κB and mitogen-activated protein kinase signaling pathways

Ganoderma atrum has been used as a traditional Chinese medicine for centuries. In this study, the antitumor activity of a novel G. atrum polysaccharide (PSG-1) was investigated in vitro and in vivo using S180 tumor-bearing mice. The results showed that PSG-1 significantly inhibited the proliferation of S180 via the activation of macrophages in a dose-dependent manner. PSG-1-primed macrophages exhibited a higher tumoricidal activity than untreated macrophages. Administration of PSG-1 significantly inhibited the growth of transplantable sarcoma S180-bearing mice and increased macrophage phagocytosis and the levels of cytokines and nitride oxide. Expression of Toll-like receptor (TLR) 4 in the membrane was markedly increased in PSG-1-treated groups, suggesting that it may be a possible receptor for PSG-1. PSG-1 also promoted the translocation of the p65 subunit of NF-κB from cytosol to nucleus and the degradation of IκBα. Moreover, the phosphorylation of p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinases 1/2, and c-Jun N-terminal kinase in macrophages was improved by PSG-1 in a dose-dependent manner. Therefore, it is suggested that PSG-1 may elicit its antitumor effect by improving immune system functions through TLR4-mediated NF-κB and MAPK signaling pathways.

A PP4 holoenzyme balances physiological and oncogenic nuclear factor-kappa B signaling in T lymphocytes

Signal transduction to nuclear factor-kappa B (NF-κB) involves multiple kinases and phosphorylated target proteins, but little is known about signal termination by dephosphorylation. By RNAi screening, we have identified protein phosphatase 4 regulatory subunit 1 (PP4R1) as a negative regulator of NF-κB activity in T lymphocytes. PP4R1 formed part of a distinct PP4 holoenzyme and bridged the inhibitor of NF-κB kinase (IKK) complex and the phosphatase PP4c, thereby directing PP4c activity to dephosphorylate and inactivate the IKK complex. PP4R1 expression was triggered upon activation and proliferation of primary human T lymphocytes and deficiency for PP4R1 caused sustained and increased IKK activity, T cell hyperactivation, and aberrant NF-κB signaling in NF-κB-addicted T cell lymphomas. Collectively, our results unravel PP4R1 as a previously unknown activation-associated negative regulator of IKK activity in lymphocytes whose downregulation promotes oncogenic NF-κB signaling in a subgroup of T cell lymphomas.

Antitumor activity and immunomodulatory effects of the intraperitoneal administration of Kanglaite in vivo in Lewis lung carcinoma

AIMS OF THE STUDY

Kanglaite (KLT) is a useful antitumor drug with proven effects when combined with chemotherapy, radiotherapy or surgery. We hypothesize that KLT has antitumor activity and immunomodulatory effects in Lewis lung carcinoma.

MATERIALS AND METHODS

C57BL/6 mice with Lewis lung carcinoma were divided into four groups: the control group (C), cisplatin group (1 mg/kg, DDP), low KLT group (6.25 ml/kg body weight [L]), and high KLT group (12.5 ml/kg body weight [H]). T cell proliferation was determined by the MTT assay. Nuclear factor-kappa B (NF-κB), inhibitor kappa B alpha (IκBα), IκB kinase (IKK) and epidermal growth factor receptor (EGFR) levels were measured by western blotting. An enzyme-linked immunosorbent assay was used to analyze the expression of interleukin-2 (IL-2).

RESULTS

Intraperitoneal KLT significantly inhibited the growth of Lewis lung carcinoma, and the spleen index was significantly higher in the L and H groups than in the C group. KLT stimulated T cell proliferation in a dose-dependent manner. Treatment with KLT at either 6.25 or 12.5 ml/kg decreased the level of NF-κB in the nucleus in a dose-dependent manner, and KLT markedly decreased the expression of IκBα, IKK and EGFR in the cytoplasm of tumor cells and overall. IL-2 was significantly increased in the supernatant of splenocytes in the H group.

CONCLUSIONS

These results demonstrate that KLT has pronounced antitumor and immunostimulatory activities in C57BL/6 mice with Lewis lung carcinoma. These may affect the regulation of NF-κB/IκB expression, in addition to cytokines such as IL-2 and EGFR. Further work needs to investigate the relevant signaling pathway effects, but our findings suggest that KLT may be a promising antitumor drug for clinical use.

1-Dehydro-[10]-gingerdione from ginger inhibits IKKβ activity for NF-κB activation and suppresses NF-κB-regulated expression of inflammatory genes

BACKGROUND AND PURPOSE

Pungent constituents of ginger (Zingiber officinale) have beneficial effects on inflammatory pain and arthritic swelling. However, the molecular basis for these pharmacological properties is only partially understood. Here, we investigated the molecular target of 1-dehydro-[10]-gingerdione (D10G), one of the pungent constituents of ginger, that mediates its suppression of NF-κB-regulated expression of inflammatory genes linked to toll-like receptor (TLR)-mediated innate immunity.

EXPERIMENTAL APPROACH

RAW 264.7 macrophages or primary macrophages-derived from bone marrows of C57BL/6 or C3H/HeJ mice were stimulated with the TLR4 agonist LPS in the presence of D10G. Catalytic activity of inhibitory κB (IκB) kinase β (IKKβ) was determined by a kinase assay and immunoblot analysis, and the expression of inflammatory genes by RT-PCR analysis and a promoter-dependent reporter assay.

KEY RESULTS

D10G directly inhibited the catalytic activity of cell-free IKKβ. Moreover, D10G irreversibly inhibited cytoplasmic IKKβ-catalysed IκBα phosphorylation in macrophages activated by TLR agonists or TNF-α, and also IKKβ vector-elicited NF-κB transcriptional activity in these cells. These effects of D10G were abolished by substitution of the Cys(179) with Ala in the activation loop of IKKβ, indicating a direct interacting site of D10G. This mechanism was shown to mediate D10G-induced disruption of NF-κB activation in LPS-stimulated macrophages and the suppression of NF-κB-regulated gene expression of inducible NOS, COX-2 and IL-6.

CONCLUSION AND IMPLICATIONS

This study demonstrates that IKKβ is a molecular target of D10G involved in the suppression of NF-κB-regulated gene expression in LPS-activated macrophages; this suggests D10G has therapeutic potential in NF-κB-associated inflammation and autoimmune disorders.

HTLV-1 infection: what determines the risk of inflammatory disease?

Human T-lymphotropic virus type 1 (HTLV-1) is an exogenous retrovirus that persists lifelong in the infected host. Infection has been linked to a spectrum of diverse diseases: adult T cell leukemia, encephalomyelopathy, and predisposition to opportunistic bacterial and helminth infections. Applications of new technologies and biological concepts to the field have provided new insights into viral persistence and pathogenesis in HTLV-1 infection. Here, we summarize the emerging concepts of dynamic HTLV-1-host interactions and propose that chronic interferon (IFN) production causes tissue damage in HTLV-1-associated inflammatory diseases.

The B-cell receptor signaling pathway as a therapeutic target in CLL

Targeted therapy with imatinib and other selective tyrosine kinase inhibitors has transformed the treatment of chronic myeloid leukemia. Unlike chronic myeloid leukemia, chronic lymphocytic leukemia (CLL) lacks a common genetic aberration amenable to therapeutic targeting. However, our understanding of normal B-cell versus CLL biology points to differences in properties of B-cell receptor (BCR) signaling that may be amenable to selective therapeutic targeting. The application of mouse models has further expanded this understanding and provides information about targets in the BCR signaling pathway that may have other important functions in cell development or long-term health. In addition, overexpression or knockout of selected targets offers the potential to validate targets genetically using new mouse models of CLL. The initial success of BCR-targeted therapies has promoted much excitement in the field of CLL. At the present time, GS-1101, which reversibly inhibits PI3Kδ, and ibrutinib (PCI-32765), an irreversible inhibitor of Bruton tyrosine kinase, have generated the most promising early results in clinical trials including predominately refractory CLL where durable disease control has been observed. This review provides a summary of BCR signaling, tools for studying this pathway relevant to drug development in CLL, and early progress made with therapeutics targeting BCR-related kinases.

Structural insights into the assembly of CARMA1 and BCL10

The CBM complex (CARMA1, BCL10 and MALT1) plays a crucial role in B and T lymphocyte activation. CARMA1 serves as a scaffold for BCL10, MALT1 and other effector proteins and regulates various signaling pathways related to the immune response. The assembly of CARMA1 and BCL10 is mediated through a CARD-CARD interaction. Here, we report the crystal structure of the CARD domain of CARMA1 at a resolution of 1.75 Å. The structure consists of six helices, as previously determined for CARD domains. Structural and computational analysis identified the binding interface between CARMA1-CARD and BCL10-CARD, which consists of a basic patch in CARMA1 and an acidic patch in BCL10. Site-directed mutagenesis, co-immunoprecipitation and an NF-κB activation assay confirmed that the interface is necessary for association and downstream signaling. Our studies provide molecular insight into the assembly of CARMA1 and BCL10.

The B-cell receptor signaling pathway as a therapeutic target in CLL

Targeted therapy with imatinib and other selective tyrosine kinase inhibitors has transformed the treatment of chronic myeloid leukemia. Unlike chronic myeloid leukemia, chronic lymphocytic leukemia (CLL) lacks a common genetic aberration amenable to therapeutic targeting. However, our understanding of normal B-cell versus CLL biology points to differences in properties of B-cell receptor (BCR) signaling that may be amenable to selective therapeutic targeting. The application of mouse models has further expanded this understanding and provides information about targets in the BCR signaling pathway that may have other important functions in cell development or long-term health. In addition, overexpression or knockout of selected targets offers the potential to validate targets genetically using new mouse models of CLL. The initial success of BCR-targeted therapies has promoted much excitement in the field of CLL. At the present time, GS-1101, which reversibly inhibits PI3Kδ, and ibrutinib (PCI-32765), an irreversible inhibitor of Bruton tyrosine kinase, have generated the most promising early results in clinical trials including predominately refractory CLL where durable disease control has been observed. This review provides a summary of BCR signaling, tools for studying this pathway relevant to drug development in CLL, and early progress made with therapeutics targeting BCR-related kinases.

Genomics of the NF-κB signaling pathway: hypothesized role in ovarian cancer

OBJECTIVE

We sought to review evidence linking nuclear factor-kappa B (NF-κB) to ovarian cancer and to identify genetic variants involved in NF-κB signaling.

METHODS

PubMed was reviewed to inform on ovarian cancer biology and NF-κB signaling and to identify key genes. Public linkage disequilibrium (LD) data were analyzed to identify informative inherited variants (tagSNPs) using ldSelect.

RESULTS

We identified 319 key NF-κB genes including five NF-κB subunits, 167 activating genes, and 55 inhibiting genes. We found that the 1000 Genomes Project was the most informative LD source for most genes (92.8%), and we identified 13,027 LD bins (r (2) ≥ 0.9, minor allele frequency ≥ 0.05) and 1,018 putative-functional variants worthy of investigation. We also report that reliance on a commonly used genome-wide SNP array and genotype imputation with HapMap Phase II data provides data on only 74% of the common inherited NF-κB SNPs of interest.

CONCLUSIONS

Compelling evidence suggests that NF-κB plays a critical role in ovarian cancer, yet inherited variation in these genes has not been thoroughly assessed in relation to disease risk or outcome. We present a collection of variants in key genes and suggest creation of a custom genotyping array as an optimal approach.

Fucoxanthin inhibits the inflammatory response by suppressing the activation of NF-κB and MAPKs in lipopolysaccharide-induced RAW 264.7 macrophages

It has been previously determined that pro-inflammatory mediators including nitric oxide (NO), prostaglandin E₂ (PGE₂), tumor necrosis factor (TNF)-α, and interleukin (IL)-1β and IL-6 contribute to the courses of a variety of inflammatory diseases. In this study, we evaluated the anti-inflammatory effects of fucoxanthin (FX), a natural biologically active substance isolated from Ishige okamurae, by determining its inhibitory effects on pro-inflammatory mediators in lipopolysaccharide (LPS)-stimulated murine macrophage RAW 264.7 cells. FX induced dose-dependent reductions in the levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins and concomitant reductions in the production of NO and PGE₂. Additionally, FX was shown to suppress the production of inflammatory cytokines including IL-1β, TNF-α, and IL-6. Furthermore, FX inhibited the cytoplasmic degradation of inhibitors of B (IκB)-α and the nuclear translocation of p50 and p65 proteins, resulting in lower levels of nuclear factor (NF)-κB transactivation. Additionally, FX was shown to induce a dose-dependent inhibition of the phosphorylation of mitogen-activated protein kinases (MAPKs; JNK, ERK and p38). Collectively, the results of this study demonstrate that FX reduces the levels of pro-inflammatory mediators including NO, PGE₂, IL-1β, TNF-α, and IL-6 via the inhibition of NF-κB activation and the suppression of MAPK phosphorylation in RAW 264.7 cells. These findings reveal, in part, the molecular basis underlying the anti-inflammatory properties of FX.

TLR4 and CD14 receptors expressed in rat pineal gland trigger NFKB pathway

Nuclear factor-kappa B (NFKB), a pivotal player in inflammatory responses, is constitutively expressed in the pineal gland. Corticosterone inhibits pineal NFKB leading to an enhancement of melatonin production, while tumor necrosis factor (TNF) leads to inhibition of Aa-nat transcription and the production of N-acetylserotonin in cultured glands. The reduction in nocturnal melatonin surge favors the mounting of the inflammatory response. Despite these data, there is no clear evidence of the ability of the pineal gland to recognize molecules that signal infection. This study investigated whether the rat pineal gland expresses receptors for lipopolysaccharide (LPS), the endotoxin from the membranes of Gram-negative bacteria, and to establish the mechanism of action of LPS. Here, we show that pineal glands possess both CD14 and toll-like receptor 4 (TLR4), membrane proteins that bind LPS and trigger the NFKB pathway. LPS induced the nuclear translocation of p50/p50 and p50/RELA dimers and the synthesis of TNF. The maximal expression of TNF in cultured glands coincides with an increase in the expression of TNF receptor 1 (TNFR1) in isolated pinealocytes. In addition, LPS inhibited the synthesis of N-acetylserotonin and melatonin. Therefore, the pineal gland transduces Gram-negative endotoxin stimulation by producing TNF and inhibiting melatonin synthesis. Here, we provide evidence to reinforce the idea of an immune-pineal axis, showing that the pineal gland is a constitutive player in the innate immune response.

A novel missense mutation in the nuclear factor-κB essential modulator (NEMO) gene resulting in impaired activation of the NF-κB pathway and a unique clinical phenotype presenting as MRSA subdural empyema

INTRODUCTION

We describe a previously unreported 437 T→G missense mutation producing a V146G substitution in the first coiled-coil (CC1) domain of nuclear factor-κB essential modulator (NEMO) in a 9-month-old boy with ectodermal dysplasia with immunodeficiency who presented with methicillin-resistant Staphylococcus aureus subdural empyema. We performed in vitro experiments to determine if this novel mutation resulted in impaired NF-κB signaling.

METHODS

IκBα phosphorylation experiments were performed using a Jurkat T cell line lacking endogenous NEMO expression that was transfected with vectors containing either the wild type or the patient's V146G mutation. The cells were stimulated with TNF-α to activate the NF-κB pathway. Phosphorylated IκBα was detected by immunoblotting with anti-phospho-IκBα antibodies. Peripheral blood mononuclear cells from the patient were stimulated with TNF-α or anti-CD3 and anti-CD28. Impaired IκBα degradation was detected using antibodies against the IκBα protein.

RESULTS

While TNF-α stimulation resulted in IκBα phosphorylation in NEMO-deficient Jurkat cells reconstituted with wild-type NEMO, cell transfected with the V146G mutant exhibited a 75% reduction in phospho-IκBα. Peripheral blood mononuclear cells from the patient showed impaired degradation of IκBα after stimulation when compared with normal controls.

CONCLUSIONS

The patient's V146G mutation results in impaired NF-κB activation in vitro. The mutation extends the known N-terminal boundary within the CC1 domain that produces an ectodermal dysplasia phenotype, and defines an infectious susceptibility previously unappreciated in ectodermal dysplasia with immunodeficiency (methicillin-resistant S. aureus subdural empyema), broadening the clinical spectrum associated with the disease.

Differential cytokine regulation by NF-kappaB and AP-1 in Jurkat T-cells

Background

Activator protein (AP)-1 and nuclear factor (NF)-κB largely control T-cell activation, following binding of foreign antigens to the T-cell receptor leading to cytokine secretion. Elevated levels of pro-inflammatory cytokines and chemokines such as TNF, IL-6 and CXCL8 are associated with several human diseases including cystic fibrosis, pulmonary fibrosis and AIDS. The aim of this study was to investigate the role of the transcription factors, AP-1 and NF-κB, in IL-6 and CXCL8 regulation in Jurkat T-cells.

Results

Phorbol myristate acetate (PMA) exposure resulted in an up-regulation of AP-1 and down-regulation of NF-κB activity, however, exposure to heat killed (HK) Escherichia. coli MG1655 resulted in a dose-dependent increase in NF-κB activity without affecting AP-1. The cytokine profile revealed an up-regulation of the chemokine CXCL8 and the pro-inflammatory cytokines TNF, IL-2 and IL-6 following treatment with both PMA and HK E. coli, while the levels of the anti-inflammatory cytokine IL-10 were not affected by PMA but were significantly down-regulated by HK E. coli. AP-1 activation was significantly increased 2 h after PMA exposure and continued to increase thereafter. In contrast, NF-κB responded to PMA exposure by a rapid up-regulation followed by a subsequent down-regulation. Increased intracellular Ca²⁺ concentrations countered the down-regulation of NF-κB by PMA, while similar treatment with calcium ionophore resulted in a reduced NF-κB activity following induction with HK E. coli. In order to further study NF-κB activation, we considered two up-stream signalling proteins, PKC and Bcl10. Phosphorylated-PKC levels increased in response to PMA and HK E. coli, while Bcl10 levels significantly decreased following PMA treatment. Using an NF-κB activation inhibitor, we observed complete inhibition of IL-6 expression while CXCL8 levels only decreased by 40% at the highest concentration. Treatment of Jurkat T-cells with PMA in the presence of JNK-inhibitor suppressed both CXCL8 and IL-6 while PKC-inhibitor primarily decreased CXCL8 expression.

Conclusion

The present study shows that NF-κB regulated IL-6 but not CXCL8. This complex regulation of CXCL8 suggests that there is a need to further evaluate the signalling pathways in order to develop new treatment for diseases with elevated CXCL8 levels, such as AIDS and autoimmune diseases.

Molecular basis of lysophosphatidic acid-induced NF-κB activation

PKC, β-arrestin 2, CARMA3, BCL10, MALT1, TRAF6 and MEKK3 are signaling proteins that have a key role in G protein-coupled receptor (GPCR)-mediated activation of nuclear factor-κB (NF-κB) pathway in nonhematopoietic cells in response to lysophosphatidic acid (LPA) stimulation. The PKC, β-arrestin 2, CARMA3-BCL10-MALT1-TRAF6 signalosome, and MEKK3 functions as a link between GPCR signaling and IKK-NF-κB activation. Here we briefly summarize recent progress in the understanding of the molecular and biological functions of these proteins in GPCR-mediated NF-κB activation in nonhematopoietic cells.

Inhibition of MALT1 protease activity is selectively toxic for activated B cell-like diffuse large B cell lymphoma cells

Diffuse large B cell lymphoma (DLBCL) is the most common type of lymphoma in humans. The aggressive activated B cell–like (ABC) subtype of DLBCL is characterized by constitutive NF-κB activity and requires signals from CARD11, BCL10, and the paracaspase MALT1 for survival. CARD11, BCL10, and MALT1 are scaffold proteins that normally associate upon antigen receptor ligation. Signal-induced CARD11–BCL10–MALT1 (CBM) complexes couple upstream events to IκB kinase (IKK)/NF-κB activation. MALT1 also possesses a recently recognized proteolytic activity that cleaves and inactivates the negative NF-κB regulator A20 and BCL10 upon antigen receptor ligation. Yet, the relevance of MALT1 proteolytic activity for malignant cell growth is unknown. Here, we demonstrate preassembled CBM complexes and constitutive proteolysis of the two known MALT1 substrates in ABC-DLBCL, but not in germinal center B cell–like (GCB) DLBCL. ABC-DLBCL cell treatment with a MALT1 protease inhibitor blocks A20 and BCL10 cleavage, reduces NF-κB activity, and decreases the expression of NF-κB targets genes. Finally, MALT1 paracaspase inhibition results in death and growth retardation selectively in ABC-DLBCL cells. Thus, our results indicate a growth-promoting role for MALT1 paracaspase activity in ABC-DLBCL and suggest that a pharmacological MALT1 protease inhibition could be a promising approach for lymphoma treatment.