The contribution of NF-κB signalling to immune regulation and tolerance

Genetic Polymorphisms in Exon 5 and Intron 5 and 7 of AIRE Are Associated with Rheumatoid Arthritis Risk in a Hungarian Population

BACKGROUND

Rheumatoid arthritis (RA) is chronically persistent synovitis and systemic inflammation. Although multiple contributors are detected, only one is pivotal in the neonatal period: the negative selection of autoimmune naïve T-cells by the autoimmune regulator (AIRE) transcriptional factor.

METHODS

Single-nucleotide polymorphisms (SNPs) in the DNA-binding site of AIRE may determine its function and expression. We intended to analyse site-specific allelic polymorphisms in two exon (rs878081 and rs1055311) and three intron (rs1003853, rs2075876, and rs1003854) loci with an RA risk. Our analytical case-control study analysed 270 RA patients and 322 control subjects in five different genetic models using quantitative real-time PCR (qPCR) with TaqMan® assays.

RESULTS

Statistically significant differences were found between the odds of allelic polymorphisms in the loci of rs878081, rs1003854, and rs1003853 among the controls and RA patients, and the disease activity seemed to be significantly associated with the genotypic subgroups of rs878081 and rs1055311. Our in silico analysis supported this, suggesting that allele-specific alterations in the binding affinity of transcriptional factor families might determine RA activity.

CONCLUSION

Our findings highlight the involvement of neonatal self-tolerance in RA pathogenesis, providing novel insights into disease development and paving the way for an analysis of further site-specific genetic polymorphisms in AIRE to expand the intervention time for RA.

Transcription Factors in Prostate Cancer: Insights for Disease Development and Diagnostic and Therapeutic Approaches

Transcription factors (TFs) are proteins essential for the regulation of gene expression, and they regulate the genes involved in different cellular processes, such as proliferation, differentiation, survival, and apoptosis. Although their expression is essential in normal physiological conditions, abnormal regulation of TFs plays critical role in several diseases, including cancer. In prostate cancer, the most common malignancy in men, TFs are known to play crucial roles in the initiation, progression, and resistance to therapy of the disease. Understanding the interplay between these TFs and their downstream targets provides insights into the molecular basis of prostate cancer pathogenesis. In this review, we discuss the involvement of key TFs, including the E26 Transformation-Specific (ETS) Family (ERG and SPDEF), NF-κB, Activating Protein-1 (AP-1), MYC, and androgen receptor (AR), in prostate cancer while focusing on the molecular mechanisms involved in prostate cancer development. We also discuss emerging diagnostic strategies, early detection, and risk stratification using TFs. Furthermore, we explore the development of therapeutic interventions targeting TF pathways, including the use of small molecule inhibitors, gene therapies, and immunotherapies, aimed at disrupting oncogenic TF signaling and improving patient outcomes. Understanding the complex regulation of TFs in prostate cancer provides valuable insights into disease biology, which ultimately may lead to advancing precision approaches for patients.

Matrix metalloproteinase-8 regulates dendritic cell tolerance in late polymicrobial sepsis via the nuclear factor kappa-B p65/β-catenin pathway

Background

Tolerogenic dendritic cells (DCs) are associated with poor prognosis of sepsis. Matrix metalloproteinases (MMPs) have been shown to have immunomodulatory effects. However, whether MMPs are involved in the functional reprogramming of DCs is unknown. The study aims to investigate the role of MMPs in sepsis-induced DCs tolerance and the potential mechanisms.

Methods

A murine model of late sepsis was induced by cecal ligation and puncture (CLP). The expression levels of members of the MMP family were detected in sepsis-induced tolerogenic DCs by using microarray assessment. The potential roles and mechanisms underlying MMP8 in the differentiation, maturation and functional reprogramming of DCs during late sepsis were assessed both in vitro and in vivo.

Results

DCs from late septic mice expressed higher levels of MMP8, MMP9, MMP14, MMP19, MMP25 and MMP27, and MMP8 levels were the highest. MMP8 deficiency significantly alleviated sepsis-induced immune tolerance of DCs both in vivo and in vitro. Adoptive transfer of MMP8 knockdown post-septic bone marrow-derived DCs protected mice against sepsis-associated lethality and organ dysfunction, inhibited regulatory T-cell expansion and enhanced Th1 response. Furthermore, the effect of MMP8 on DC tolerance was found to be associated with the nuclear factor kappa-B p65/β-catenin pathway.

Conclusions

Increased MMP8 levels in septic DCs might serve as a negative feedback loop, thereby suppressing the proinflammatory response and inducing DC tolerance.

Tolerogenic dendritic cells and TLR4/IRAK4/NF-κB signaling pathway in allergic rhinitis

Dendritic cells (DCs), central participants in the allergic immune response, can capture and present allergens leading to allergic inflammation in the immunopathogenesis of allergic rhinitis (AR). In addition to initiating antigen-specific immune responses, DCs induce tolerance and modulate immune homeostasis. As a special type of DCs, tolerogenic DCs (tolDCs) achieve immune tolerance mainly by suppressing effector T cell responses and inducing regulatory T cells (Tregs). TolDCs suppress allergic inflammation by modulating immune tolerance, thereby reducing symptoms of AR. Activation of the TLR4/IRAK4/NF-κB signaling pathway contributes to the release of inflammatory cytokines, and inhibitors of this signaling pathway induce the production of tolDCs to alleviate allergic inflammatory responses. This review focuses on the relationship between tolDCs and TLR4/IRAK4/NF-κB signaling pathway with AR.

Antibiotics-induced depression in mice via the microbiota-gut-brain axis

BACKGROUND

Intestinal dysbacteriosis is associated with depression. This study aimed to establish an antibiotics-induced depression mouse model and explore the mechanism of antibiotic-induced depression.

METHODS

C57BL/6 J mice were treated with antibiotics to prepare the antibiotic-induced depression mouse model. Behavioral tests and depression-related bio-markers were examined. To understand the abundance of different bacteria in intestinal flora and screen out the predominant bacterial species, metagenomic analysis of feces was carried out. Finally, we detected the expression of NF-κB-p65 and p-NF-κB-p65 in PFC and the hippocampus using Western blot.

RESULTS

Mixtures A and B caused depression-like behavior in mice. Norepinephrine, 5-hydroxytryptamine, and brain-derived neurotrophic factor in hippocampus and PFC of antibiotic-induced depression mice significantly decreased. The serum adrenocorticotropic hormone and corticosterone concentrations increased. The abundance values of Bacteroides thetaiotaomicron, Klebsiella oxytoca, and Klebsiella aerogenes in antibiotic-induced depression mice significantly increased, and the characteristic KO genes and metabolic pathways in antibiotic-induced depression mice were significantly different with in CUMS depression mice (the positive control) and normal mice. The relative levels of p-NF-κB-p65 in antibiotics-induced depression mice were significantly higher than in normal mice.

LIMITATIONS

How dysbacteriosis induces inflammation in the central nervous system is unclear.

CONCLUSIONS

Specific antibiotic mixture can cause depression-like behavior and changes of depression-related bio-markers in mice. The antibiotic-induced depression mice display changes in the species and metabolism of intestinal bacterial flora. The activation of NF-κB inflammatory signaling pathway in the central nervous system may act as one of the mechanisms in the development of antibiotic-induced depression.

Changes in expression of nuclear factor kappa B subunits in the ovine thymus during early pregnancy

There is a pregnant maternal immunological tolerance that protects the fetus and promotes its growth, and nuclear factor kappa B (NF-κB) family participates in the regulation of innate immune and adaptive immune responses. The thymus is related to establishing central tolerance, and early pregnancy has effects on expression of a good number of genes and proteins in the maternal thymus in sheep. However, it is unclear whether early pregnancy changes expression of NF-κB subunits in the ovine thymus. In this study, the thymic samples were collected from day 16 of non-pregnant ewes, and days 13, 16 and 25 of pregnant ewes, and the expression of NF-κB members (NF-κB1, NF-κB2, RelA, RelB and c-Rel) was analyzed through real-time quantitative PCR, Western blot and immunohistochemical analysis. The results showed that c-Rel mRNA and protein upregulated at day 25 of pregnancy, and NF-κB1 mRNA and proteins increased at days 16 and 25 of pregnancy, and RelB mRNA and proteins enhanced during early pregnancy. However, expression levels of NF-κB2 and RelA were decreased during early pregnancy, but upregulated from day 13 to 25 of pregnancy. In addition, the RelA protein was located in the epithelial reticular cells, capillaries and thymic corpuscles. This paper reported for the first time that early pregnancy induced expression of NF-κB1, RelB and c-Rel, but inhibited expression of NF-κB2 and RelA in the maternal thymus during early pregnancy, which is involved in the central immune tolerance, and helpful for successful pregnancy in sheep.

Activation of NF-κB signaling by the dense granule protein GRA15 of a newly isolated type 1 Toxoplasma gondii strain

Background

It has been reported that the NF-κB pathway, an important component of host defense system against pathogens infections, can be differentially modulated by different Toxoplasma gondii strains, depending on the polymorphism of the GRA15 protein. The recently isolated Toxoplasma strain T.gHB1 is a type 1 (ToxoDB#10) strain but shows different virulence determination mechanisms compared to the classic type 1 strains like RH (ToxoDB#10). Therefore, it is worth investigating whether the T.gHB1 strain (ToxoDB#10) affects the host NF-κB signaling pathway.

Methods

The effects of T.gHB1 (ToxoDB#10) on host NF-κB pathway were investigated in HEK293T cells. The GRA15 gene product was analyzed by bioinformatics, and its effect on NF-κB activation was examined by Western blotting and nuclear translocation of p65. Different truncations of T.gHB1 GRA15 were constructed to map the critical domains for NF-κB activation.

Results

We demonstrated that the NF-κB pathway signaling pathway could be activated by the newly identified type 1 T.gHB1 strain (ToxoDB#10) of Toxoplasma, while the classic type 1 strain RH (ToxoDB#10) did not. T.gHB1 GRA15 possesses only one transmembrane region with an extended C terminal region, which is distinct from that of classic type 1 (ToxoDB#10) and type 2 (ToxoDB#1) strains. T.gHB1 GRA15 could clearly induce IκBα phosphorylation and p65 nuclear translocation. Dual luciferase assays in HEK293T cells revealed a requirement for 194–518 aa of T.gHB1 GRA15 to effectively activate NF-κB.

Conclusions

The overall results indicated that the newly isolated type 1 isolate T.gHB1 (ToxoDB#10) had a unique GRA15, which could activate the host NF-κB signaling through inducing IκBα phosphorylation and p65 nuclear translocation. These results provide new insights for our understanding of the interaction between Toxoplasma parasites and its hosts.

Graphical Abstract

Agomelatine Changed the Expression and Methylation Status of Inflammatory Genes in Blood and Brain Structures of Male Wistar Rats after Chronic Mild Stress Procedure

The preclinical research conducted so far suggest that depression development may be influenced by the inflammatory pathways both at the periphery and within the central nervous system. Furthermore, inflammation is considered to be strongly connected with antidepressant treatment resistance. Thus, this study explores whether the chronic mild stress (CMS) procedure and agomelatine treatment induce changes in TGFA, TGFB, IRF1, PTGS2 and IKBKB expression and methylation status in peripheral blood mononuclear cells (PBMCs) and in the brain structures of rats. Adult male Wistar rats were subjected to the CMS and further divided into matched subgroups to receive vehicle or agomelatine. TaqMan gene expression assay and methylation-sensitive high-resolution melting (MS-HRM) were used to evaluate the expression of the genes and the methylation status of their promoters, respectively. Our findings confirm that both CMS and antidepressant agomelatine treatment influenced the expression level and methylation status of the promoter region of investigated genes in PBMCs and the brain. What is more, the present study showed that response to either stress stimuli or agomelatine differed between brain structures. Concluding, our results indicate that TGFA, TGFB, PTGS2, IRF1 and IKBKB could be associated with depression and its treatment.

Inferred Causal Mechanisms of Persistent FMDV Infection in Cattle from Differential Gene Expression in the Nasopharyngeal Mucosa

Foot-and-mouth disease virus (FMDV) can persistently infect pharyngeal epithelia in ruminants but not in pigs. Our previous studies demonstrated that persistent FMDV infection in cattle was associated with under-expression of several chemokines that recruit immune cells. This report focuses on the analysis of differentially expressed genes (DEG) identified during the transitional phase of infection, defined as the period when animals diverge between becoming carriers or terminators. During this phase, Th17-stimulating cytokines (IL6 and IL23A) and Th17-recruiting chemokines (CCL14 and CCL20) were upregulated in animals that were still infected (transitional carriers) compared to those that had recently cleared infection (terminators), whereas chemokines recruiting neutrophils and CD8+ T effector cells (CCL3 and ELR+CXCLs) were downregulated. Upregulated Th17-specific receptor, CCR6, and Th17-associated genes, CD146, MIR155, and ThPOK, suggested increased Th17 cell activity in transitional carriers. However, a complex interplay of the Th17 regulatory axis was indicated by non-significant upregulation of IL17A and downregulation of IL17F, two hallmarks of TH17 activity. Other DEG suggested that transitional carriers had upregulated aryl hydrocarbon receptor (AHR), non-canonical NFκB signaling, and downregulated canonical NFκB signaling. The results described herein provide novel insights into the mechanisms of establishment of FMDV persistence. Additionally, the fact that ruminants, unlike pigs, produce a large amount of AHR ligands suggests a plausible explanation of why FMDV persists in ruminants, but not in pigs.

Extrathymic AIRE-expressing cells: Friends or foes in autoimmunity and cancer?

Auto-immune regulator (AIRE) is a transcription factor that is mainly known for its crucial role in the thymus. Here, AIRE ensures central tolerance by promoting the expression of peripheral tissue antigens in thymic epithelial cells, which is essential for the negative selection of autoreactive T cells. Intriguingly, AIRE expressing cells have recently been identified in other tissues outside the thymus as well. However, the exact function of these extrathymic AIRE expressing cells (eTACs) remains largely enigmatic. Human eTACs are mainly found in secondary lymphoid tissues under homeostatic conditions, but are also found in pathologies such as the inflamed tissues of patients with autoimmune diseases and in various cancer tissues. eTACs have been demonstrated to express dendritic cell (DC)-like markers, such as MHCII, CD40 and CD127, but also CCR7, IDO and PD-L1. Interestingly, eTACs lack high expression of co-stimulatory molecules, such as CD80 or CD86. In mice, different types of peripheral AIRE expressing cells have been described, including cells with an innate lymphoid cell-like phenotype and antigen presenting cell (APC) function. These findings suggest that eTACs are APCs with the possibility to modulate or inhibit immune responses, which is confirmed by functional murine studies demonstrating the ability of eTACs to induce tolerance in autoreactive T cells. The potential immunomodulatory function of eTACs makes them promising targets to restore tolerance in autoimmunity or improve immunotherapy in cancer settings. Yet, this requires a better understanding of these cells and the molecular mechanisms involved. In this review we aim to summarize the current knowledge and understanding of eTACs, including their putative roles in health and disease.

Nalbuphine alleviates inflammation by down-regulating NF-κB in an acute inflammatory visceral pain rat model

Introduction

Nalbuphine can relieve patients’ inflammation response after surgery compared to other opioid drugs. However, its molecular mechanism has not been clear. Activation of NF-κB signaling pathway under oxidative stress and inflammation can maintain pain escalation.

Methods

We firstly investigated the effect of nalbuphine on writhing test and mechanical allodynia using a rat model of inflammatory visceral pain (acetic acid (AA) administrated). Cytokines (including tumor necrosis factor (TNF)-α, Interleukin (IL)-1β, IL-2, and IL-6 in plasma were tested with ELISA technology. Expression levels of TNF-α, IκBα and p-NF-κB p65 at the spinal cord (L3–5) were measured by western blot or RT-qPCR.

Results

We found that the paw withdrawal threshold (PWT) values of rats were reduced in the model group, while the numbers of writhing, levels of IL-1β, IL-2, IL-6, and TNF-α in plasma, and p-NF-κB protein and its gene expressions in the lumbar spinal cord were up-regulated. Subcutaneously injection of nalbuphine (10 μg/kg) or PDTC (NF-κB inhibitor) attenuated acetic acid-induced inflammatory pain, and this was associated with reversal of up-regulated IL-1β, IL-2, IL-6, and TNF-α in both plasma and spinal cord. Furthermore, acetic acid increased p-NF-κB and TNF-α protein levels in the white matter of the spinal cord, which was attenuated by nalbuphine. These results suggested that nalbuphine can significantly ameliorate inflammatory pain via modulating the expression of NF-κB p65 as well as inflammation factors level in the spinal cord.

Conclusion

In conclusion, nalbuphine inhibits inflammation through down-regulating NF-κB pathway at the spinal cord in a rat model of inflammatory visceral pain.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40360-022-00573-7.

The Signaling Pathways and Targets of Natural Compounds from Traditional Chinese Medicine in Treating Ischemic Stroke

Ischemic stroke (IS) is a common neurological disorder associated with high disability rates and mortality rates. At present, recombinant tissue plasminogen activator (r-tPA) is the only US(FDA)-approved drug for IS. However, due to the narrow therapeutic window and risk of intracerebral hemorrhage, r-tPA is currently used in less than 5% of stroke patients. Natural compounds have been widely used in the treatment of IS in China and have a wide range of therapeutic effects on IS by regulating multiple targets and signaling pathways. The keywords "ischemia stroke, traditional Chinese Medicine, Chinese herbal medicine, natural compounds" were used to search the relevant literature in PubMed and other databases over the past five years. The results showed that JAK/STAT, NF-κB, MAPK, Notch, Nrf2, and PI3K/Akt are the key pathways, and SIRT1, MMP9, TLR4, HIF-α are the key targets for the natural compounds from traditional Chinese medicine in treating IS. This study aims to update and summarize the signaling pathways and targets of natural compounds in the treatment of IS, and provide a base of information for the future development of effective treatments for IS.

RelB upregulates PD-L1 and exacerbates prostate cancer immune evasion

Background

The interaction between programmed death receptor (PD-1) and its ligand (PD-L1) is essential for suppressing activated T-lymphocytes. However, the precise mechanisms underlying PD-L1 overexpression in tumours have yet to be fully elucidated. Here, we describe that RelB participates in the immune evasion of prostate cancer (PCa) via cis/trans transcriptional upregulation of PD-L1.

Methods

Based on transcriptome results, RelB was manipulated in multiple human and murine PCa cell lines. Activated CD4⁺ and CD8⁺ T cells were cocultured with PCa cells with different levels of RelB to examine the effect of tumourous RelB on T cell immunity. Male mice were injected with murine PCa cells to validate the effect of RelB on the PD-1/PD-L1-mediated immune checkpoint using both tumour growth and metastatic experimental models.

Results

PD-L1 is uniquely expressed at a high level in PCa with high constitutive RelB and correlates with the patients’ Gleason scores. Indeed, a high level of PD-L1 is associated with RelB nuclear translocation in AR-negative aggressive PCa cells. Conversely, the silencing of RelB in advanced PCa cells resulted in reduced PD-L1 expression and enhanced susceptibility of PCa cells to the T cell immune response in vitro and in vivo. Mechanistically, a proximal NF-κB enhancer element was identified in the core promoter region of the human CD274 gene, which is responsible for RelB-mediated PD-L1 transcriptional activation. This finding provides an informative insight into immune checkpoint blockade by administering RelB within the tumour microenvironment.

Conclusion

This study deciphers the molecular mechanism by which tumourous RelB contributes to immune evasion by inhibiting T cell immunity via the amplification of the PD-L1/PD-1-mediated immune checkpoint.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02243-2.

Combination of tetrandrine and 3-n-butylphthalide protects against cerebral ischemia-reperfusion injury via ATF2/TLR4 pathway

OBJECTIVE

Cerebral infarction (CI) is the mayor reason of death in China. Reperfusion is the only immediate treatment for acute cerebral infarction. However, blood reperfusion recovery may cause ischemia-reperfusion (I/R) injuries. The purpose of this study was to investigate the effects of Tetrandrine (TTD) and 3-n-Butylphthalide (NBP) on cerebral I/R injury.

MATERIALS AND METHODS

I/R was used to establish CI model in vivo. TTD was performed to analyze cerebral infarction volume. OGD was applied to establish CI model in vitro. Flow cytometry and TUNEL assays were utilized to determine the cell death. ELISA was conducted to determine the release of cytokines. mRNA and protein expressions were detected using qRT-PCR and western blot.

RESULTS

We found that NBP + TTD treatment significantly reduced cerebral infarction volume and inhibited the death of neurons in vivo. Moreover, NBP + TTD treatment suppressed the apoptosis and inflammatory response of neurons in vitro. Additionally, NBP + TTD suppressed the expression of activator transcription factor 2 (ATF2). However, overexpression of ATF2 contributed to the degeneration of neurons. Moreover, ATF2 transcriptionally activated Toll-like receptor 4 (TLR4). NBP + TTD inactivated ATF2/TLR4 signaling.

CONCLUSIONS

Taken together, TTD combined with NBP protected against cerebral infarction by inhibiting the inflammatory response and neuronal cell apoptosis via inactivating ATF2/TLR4 signaling pathways. This may provide an alternative for I/R injury.

Molecular mechanisms underlying macrophage immunomodulatory activity of Rubus chingii Hu polysaccharides

The present study was to investigate the mechanisms involved in macrophage activation by polysaccharides from the fruits of Rubus chingii Hu (RFPs). The results showed that RFPs enhanced pinocytic and phagocytic activity, promoted the expression and secretion of inflammatory factors (ROS, PTGS2, iNOS, IL-6, IL-10 and TNF-α) and chemokines (CCL2 and CXCL10), and boosted the expression of accessory and costimulatory molecules (CD40, CD80, CD86, MHC-I and MHC-II). RNA-Seq analysis identified 2564 DEGs, 1710 GO terms and 101 KEGG pathways. TNF was identified as the core gene via analysis of pathway information integration and PPI network. The western blot analysis combined with functional verification assay confirmed that MAPK, NF-κB and Jak-STAT pathways were essential to RFPs-mediated macrophage activation. TLR2 was revealed to be the functional receptor and involved in the early recognition of RFPs. These results indicated that RFPs modulated macrophage immune response mainly through TLR2-dependent MAPK, NF-κB and Jak-STAT pathways.

Immunological mechanisms underlying progression of chronic wounds in recessive dystrophic epidermolysis bullosa

Hereditary epidermolysis bullosa (EB) is a mechanobullous skin fragility disorder characterized by defective epithelial adhesion, leading to mechanical stress‐induced skin blistering. Based on the level of tissue separation within the dermal‐epidermal junction, EB is categorized into simplex (EBS), junctional (JEB), dystrophic (DEB) and Kindler syndrome. There is no cure for EB, and painful chronic cutaneous wounds are one of the major complications in recessive (RDEB) patients. Although RDEB is considered a cutaneous disease, recent data support the underlying systemic immunological defects. Furthermore, chronic wounds are often colonized with pathogenic microbiota, leading to excessive inflammation and altered wound healing. Consequently, patients with RDEB suffer from a painful sensation of chronic, cutaneous itching/burning and an endless battle with bacterial infections. To improve their quality of life and life expectancy, it is important to prevent cutaneous infections, dampen chronic inflammation and stimulate wound healing. A clear scientific understanding of the immunological events underlying the maintenance of chronic poorly healing wounds in RDEB patients is necessary to improve disease management and better understand other wound healing disorders. In this review, we summarize current knowledge of the role of professional phagocytes, such as neutrophils, macrophages and dendritic cells, the role of T‐cell‐mediated immunity in lymphoid organs, and the association of microbiota with poor wound healing in RDEB. We conclude that RDEB patients have an underlying immunity defect that seems to affect antibacterial immunity.

Targeting neuroinflammation to treat cerebral ischemia - The role of TIGAR/NADPH axis

Cerebral ischemia is a disease of ischemic necrosis of brain tissue caused by intracranial artery stenosis or occlusion and cerebral artery embolization. Neuroinflammation plays an important role in the pathophysiology of cerebral ischemia. Microglia, astrocytes, leukocytes and other cells that release a variety of inflammatory factors involved in neuroinflammation may play a damaging or protective role during the process of cerebral ischemia. TP53-induced glycolysis and apoptotic regulators (TIGAR) may facilitate the production of nicotinamide adenine dinucleotide phosphoric acid (NADPH) via the pentose phosphate pathway (PPP) to inhibit oxidative stress and neuroinflammation. TIGAR can also directly inhibit NF-κB to inhibit neuroinflammation. TIGAR thus protect against cerebral ischemic injury. Exogenous NADPH can inhibit neuroinflammation by inhibiting oxidative stress and regulating a variety of signals. However, since NADPH oxidase (NOX) may use NADPH as a substrate to generate reactive oxygen species (ROS) to mediate neuroinflammation, the combination of NADPH and NOX inhibitors may produce more powerful anti-neuroinflammatory effects. Here, we review the cells and regulatory signals involved in neuroinflammation during cerebral ischemia, and discuss the possible mechanisms of targeting neuroinflammation in the treatment of cerebral ischemia with TIGAR/NADPH axis, so as to provide new ideas for the prevention and treatment of cerebral ischemia.

Chronic Mild Stress and Venlafaxine Treatment Were Associated with Altered Expression Level and Methylation Status of New Candidate Inflammatory Genes in PBMCs and Brain Structures of Wistar Rats

Preclinical studies conducted to date suggest that depression could be elicited by the elevated expression of proinflammatory molecules: these play a key role in the mediation of neurochemical, neuroendocrine and behavioral changes. Thus, this study investigates the effect of chronic mild stress (CMS) and administration of venlafaxine (SSRI) on the expression and methylation status of new target inflammatory genes: TGFA, TGFB, IRF1, PTGS2 and IKBKB, in peripheral blood mononuclear cells (PMBCs) and in selected brain structures of rats. Adult male Wistar rats were subjected to the CMS and further divided into matched subgroups to receive vehicle or venlafaxine. TaqMan gene expression assay and methylation-sensitive high-resolution melting (MS-HRM) were used to evaluate the expression of the genes and the methylation status of their promoters, respectively. Our results indicate that both CMS and chronic treatment with venlafaxine were associated with changes in expression of the studied genes and their promoter methylation status in PMBCs and the brain. Moreover, the effect of antidepressant administration clearly differed between brain structures. Summarizing, our results confirm at least a partial association between TGFA, TGFB, IRF1, PTGS2 and IKBKB and depressive disorders.

Danhong Injection Attenuates Cerebral Ischemia-Reperfusion Injury in Rats Through the Suppression of the Neuroinflammation

Neuroinflammation is one of the major causes of damage of the central nervous system (CNS) and plays a vital role in the pathogenesis of cerebral ischemia, which can result in long-term disability and neuronal death. Danhong injection (DHI), a traditional Chinese medicine injection, has been applied to the clinical treatment of cerebral stoke for many years. In this study, we investigated the protective effects of DHI on cerebral ischemia-reperfusion injury (CIRI) in rats and explored its potential anti-neuroinflammatory properties. CIRI in adult male SD rats was induced by middle cerebral artery occlusion (MCAO) for 1 h and reperfusion for 24 h. Results showed that DHI (0.5, 1, and 2 ml/kg) dose-dependently improved the neurological deficits and alleviated cerebral infarct volume and histopathological damage of the cerebral cortex caused by CIRI. Moreover, DHI (0.5, 1, and 2 ml/kg) inhibited the mRNA expressions of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), intercellular cell adhesion molecule-1 (ICAM-1), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) in ischemic brains, downregulated TNF-α, IL-1β, and monocyte chemotactic protein-1 (MCP-1) levels in serum, and reduced the neutrophil infiltration (myeloperoxidase, MPO) in ischemic brains, in a dose-dependent manner. Immunohistochemical staining results also revealed that DHI dose-dependently diminished the protein expressions of ICAM-1 and COX-2, and suppressed the activation of microglia (ionized calcium-binding adapter molecule 1, Iba-1) and astrocyte (glial fibrillary acidic protein, GFAP) in the cerebral cortex. Western blot analysis showed that DHI significantly downregulated the phosphorylation levels of the proteins in nuclear factor κB (NF-κB) and mitogen-activated protein kinas (MAPK) signaling pathways in ischemic brains. These results indicate that DHI exerts anti-neuroinflammatory effects against CIRI, which contribute to the amelioration of CNS damage.

Shikonin-mediated PD-L1 degradation suppresses immune evasion in pancreatic cancer by inhibiting NF-κB/STAT3 and NF-κB/CSN5 signaling pathways

BACKGROUND

Pancreatic cancer (PC) is a highly fatal malignancy with few effective therapies currently available. Recent studies have shown that PD-L1 inhibitors could be potential therapeutic targets for the treatment of PC. The present study aims to investigate the effect of Shikonin on immune evasion in PC with the involvement of the PD-L1 degradation.

METHODS

Initially, the expression patterns of PD-L1 and NF-κB in PC were predicted in-silico using the GEPIA database, and were subsequently validated using PC tissues. Thereafter, the correlation of NF-κB with STAT3, CSN5 and PD-L1 was examined. PC cells were treated with Shikonin, NF-κB inhibitor, STAT3 activator, and CSN5 overexpression plasmid to investigate effects on PD-L1 glycosylation and immune evasion in PC. Finally, in vivo tumor formation was induced in C57BL/6J mice, in order to verify the in vitro results.

RESULTS

PD-L1, NF-κB, NF-κB p65, STAT3, and CSN5 were highly expressed in PC samples, and NF-κB was positively correlated with STAT3/CSN5/PD-L1. Inhibition of NF-κB decreased PD-L1 glycosylation and increased PD-L1 degradation, whereas activated STAT3 and overexpressed CSN5 reversed these trends. Shikonin blocked immune evasion in PC, and lowered the expression of PD-L1, NF-κB, NF-κB p65, STAT3 and CSN5 in vivo and in vitro.

CONCLUSION

The findings indicated Shikonin inhibited immune evasion in PC by inhibiting PD-L1 glycosylation and activating the NF-κB/STAT3 and NF-κB/CSN5 signaling pathways. These effects of Shikonin on PC cells may bear important potential therapeutic implications for the treatment of PC.

Association of -94 ATTG insertion/deletion NFkB1 and c.*126G>A NFkBIA genetic polymorphisms with oxidative and nitrosative stress biomarkers in Brazilian subjects with Parkinson's Disease

Parkinson's disease (PD) is a complex neurodegenerative disorder, resulting dopaminergic neuronal cell death in the substantia nigra. The disease is characterized by major motor impairment, being bradykinesia, rest tremor, rigidity and loss of postural reflexes the most common, while autonomic dysfunctions, sleep disturbances and psychiatric disorders are some of the wide range of non-motor symptoms. Several processes have been identified to be associated with disease development, such as mitochondrial dysfunction, oxidative/nitrosative stress and neuroinflammation. NF-κB is an important transcription factor that regulates several inflammatory elements and pathways, and polymorphisms on NFKB1 and NFKBIA genes can potentially influence redox balance towards a pro-oxidative frame, modulating disease progression. Evaluation of these polymorphisms in the redox status of PD subjects could provide new insights on the pathogenesis of this disorder. The study aimed to test associations of -94 in./del ATTG NFKB1 (rs28362491) and c.*126G > A NFKBIA (rs696) polymorphisms with PD development, and to test the influence of both polymorphisms on oxidative/nitrosative stress (OS/NS) parameters. A total of 110 Brazilian individuals were enrolled, being 55 subjects recruited from University Hospital of Londrina as the PD group, and 55 subjects matched for age, sex and ethnicity composed the healthy control (HC) group. NFkB1 and NFkBIA polymorphisms were genotyped by PCR-RFLP. Lipid hydroperoxides (LOOH), nitric oxide metabolites (NOx), advanced oxidation protein products (AOPP), sulfhydryl groups (SH), total radical trapping antioxidant parameter (TRAP) and paraoxonase-1 activity (PON-1) were assessed. Despite no association of polymorphisms on disease development was observed, in PD subjects the NFKB1 del/del genotype was associated with higher levels of LOOH, while NFkBIA GA and AA genotypes were associated with higher NOx levels, suggesting that NFkB plays a role in PD susceptbility. In conclusion, the prospect of genetic polymorphisms of elements involved in inflammation and OS/NS might be a new approach to unravel PD etiology.

Eupafolin alleviates cerebral ischemia/reperfusion injury in rats via blocking the TLR4/NF‑κB signaling pathway

Eupatorium perfoliatum L. (E. perfoliatium) has been used traditionally for treating fever, malaria and inflammation‑associated diseases. Eupafolin, the extract of E. perfoliatium, was also reported to suppress inflammation. The present study aimed to investigate the protective effects of eupafolin on cerebral ischemia/reperfusion (I/R) injury in rats and its possible underlying mechanisms. Cerebral I/R injury was induced in rats by middle cerebral artery occlusion (MCAO) for 1.5 h, followed by reperfusion. The rats were randomly assigned into six groups: Control, model, 10 mg/kg eupafolin, 20 mg/kg eupafolin, 50 mg/kg eupafolin and 20 mg/kg nimodipine. Eupafolin and nimodipine were intragastrically administrated to the rats 1 week before MCAO induction. Following reperfusion for 24 h, the neurological deficit was scored, and brain samples were harvested for evaluating encephaledema, infarct volume, oxidative stress, apoptosis, inflammation and the expression of TLR4/NF‑κB signaling. The results revealed that eupafolin decreased the neurological score, relieved encephaledema and decreased infarct volume. Eupafolin also attenuated oxidative stress, neuronal apoptosis and inflammation, with decreases in lactate dehydrogenase, malondialdehyde, TUNEL‑positive cells, Bax and caspase‑3, along with TNF‑α, IL‑1β and IL‑6, but increases in superoxide dismutase and Bcl‑2 levels. Furthermore, eupafolin may decrease the expression of TLR4 downstream proteins and proteins involved in the NF‑κB pathway. Treatment with TLR4 agonist‑LPS significantly blunted the protective effect of eupafolin on encephaledema and cerebral infarct. Meanwhile, 20 mg/kg eupafolin showed nearly equivalent effects to the positive‑control drug nimodipine. In conclusion, eupafolin protected against cerebral I/R injury in rats and the underlying mechanism may be associated with the suppression of apoptosis and inflammation via inhibiting the TLR4/ NF‑κB signaling pathway.

Regulatory T Cell Plasticity and Stability and Autoimmune Diseases

CD4⁺CD25⁺ regulatory T cells (Tregs) are a class of CD4⁺ T cells with immunosuppressive functions that play a critical role in maintaining immune homeostasis. However, in certain disease settings, Tregs demonstrate plastic differentiation, and the stability of these Tregs, which is characterized by the stable expression or protective epigenetic modifications of the transcription factor Foxp3, becomes abnormal. Plastic Tregs have some features of helper T (Th) cells, such as the secretion of Th-related cytokines and the expression of specific transcription factors in Th cells, but also still retain the expression of Foxp3, a feature of Tregs. Although such Th-like Tregs can secrete pro-inflammatory cytokines, they still possess a strong ability to inhibit specific Th cell responses. Therefore, the plastic differentiation of Tregs not only increases the complexity of the immune circumstances under pathological conditions, especially autoimmune diseases, but also shows an association with changes in the stability of Tregs. The plastic differentiation and stability change of Tregs play vital roles in the progression of diseases. This review focuses on the phenotypic characteristics, functions, and formation conditions of several plastic Tregs and also summarizes the changes of Treg stability and their effects on inhibitory function. Additionally, the effects of Treg plasticity and stability on disease prognosis for several autoimmune diseases were also investigated in order to better understand the relationship between Tregs and autoimmune diseases.

Mechanisms of Maintenance of Foot-and-Mouth Disease Virus Persistence Inferred From Genes Differentially Expressed in Nasopharyngeal Epithelia of Virus Carriers and Non-carriers

Foot-and-mouth disease virus (FMDV) causes persistent infection of nasopharyngeal epithelial cells in ~50% of infected ruminants. The mechanisms involved are not clear. This study provides a continued investigation of differentially expressed genes (DEG) identified in a previously published transcriptomic study analyzing micro-dissected epithelial samples from FMDV carriers and non-carriers. Pathway analysis of DEG indicated that immune cell trafficking, cell death and hematological system could be affected by the differential gene expression. Further examination of the DEG identified five downregulated (chemerin, CCL23, CXCL15, CXCL16, and CXCL17) and one upregulated (CCL2) chemokines in carriers compared to non-carriers. The differential expression could reduce the recruitment of neutrophils, antigen-experienced T cells and dendritic cells and increase the migration of macrophages and NK cells to the epithelia in carriers, which was supported by DEG expressed in these immune cells. Downregulated chemokine expression could be mainly due to the inhibition of canonical NFκB signaling based on DEG in the signaling pathways and transcription factor binding sites predicted from the proximal promoters. Additionally, upregulated CD69, IL33, and NID1 and downregulated CASP3, IL17RA, NCR3LG1, TP53BP1, TRAF3, and TRAF6 in carriers could inhibit the Th17 response, NK cell cytotoxicity and apoptosis. Based on our findings, we hypothesize that (1) under-expression of chemokines that recruit neutrophils, antigen-experienced T cells and dendritic cells, (2) blocking NK cell binding to target cells and (3) suppression of apoptosis induced by death receptor signaling, viral RNA, and cell-mediated cytotoxicity in the epithelia compromised virus clearance and allowed FMDV to persist. These hypothesized mechanisms provide novel information for further investigation of persistent FMDV infection.

P22077 inhibits LPS-induced inflammatory response by promoting K48-linked ubiquitination and degradation of TRAF6

Inflammation is a biological process associated with multiple human disorders such as autoimmune diseases and metabolic diseases. Therefore, alleviation of inflammation is important for disease prevention or treatment. Recently, deubiquitinating enzymes (DUBs), especially ubiquitin specific protease-7 (USP7) attracts increasing attention as a potential drug target for inflammation. As an inhibitor of USP7, P22077 has been used to study the roles of USP7 in inflammatory response and neuroblastoma growth. However, the role and precise mechanism of P22077 in anti-inflammatory is still indistinct. In this study, we demonstrated that P22077 could attenuate the release of pro-inflammatory factors including TNF-α, IL-1β, IL-6 and NO, suppress mRNA expression of COX-2 and iNOS, and inhibit activation of NF-κB and MAPKs signaling pathways in Raw264.7 cells and mouse peritoneal macrophages after LPS stimulation. In vivo study showed that P22077 could relieve inflammatory response and reduce the lung injury in C57BL/6 mice with LPS-induced endotoxemia. Mechanically, P22077 might play an anti-inflammatory role by promoting tumor necrosis factor receptor-associated factor 6 (TRAF6) degradation via K48-linked polyubiquitination. These findings provide a rationale for the role of the P22077 in anti-inflammatory pathway and the promising clinical application of P22077 to treat inflammatory diseases.

Rno-microRNA-30c-5p promotes myocardial ischemia reperfusion injury in rats through activating NF-κB pathway and targeting SIRT1

Background

This study aimed to investigate the regulatory effect of rno-microRNA-30c-5p (rno-miR-30c-5p) on myocardial ischemia reperfusion (IR) injury in rats and the underlying molecular mechanisms.

Methods

A rat model of myocardial IR injury was established. The infarct size was detected by 2,3,5-triphenyltetrazolium chloride staining. The pathologic changes of myocardial tissues were detected by hematoxylin-eosin staining. The apoptosis of myocardial cells was measured by TUNEL staining and flow cytometry. The mRNA expression of rno-miR-30c-5p and Sirtuin 1 (SIRT1) was detected by quantitative real-time PCR. The levels of IL-1β, IL-6 and TNF-α were detected by enzyme linked immunosorbent assay. The protein expression of Bax, Bcl-2, caspase-3, p-IκBα, IκBα, p-NF-κB p65, NF-κB p65 and SIRT1 was detected by Western blot. The interaction between rno-miR-30c-5p and SIRT1 was predicted by TargetScan, and further identified by dual luciferase reporter gene and RNA immunoprecipitation assay.

Results

The myocardial IR injury model was successfully established in rats. IR induced the myocardial injury in rats and increased the expression of rno-miR-30c-5p. Overexpression of rno-miR-30c-5p enhanced the inflammation, promoted the apoptosis, and activated NF-κB pathway in IR myocardial cells. SIRT1 was the target gene of rno-miR-30c-5p. Silencing of SIRT1 reversed the effects of rno-miR-30c-5p inhibitor on the apoptosis and NF-κB pathway in IR myocardial cells.

Conclusions

Rno-miR-30c-5p promoted the myocardial IR injury in rats through activating NF-κB pathway and down-regulating SIRT1.

Ketamine exerts a protective role in a cell-based model of major depressive disorder via the inhibition of apoptosis and inflammation and activation of the Krebs cycle

Major depressive disorder (MDD) is one of the most common psychiatric disorders characterized by major depressive episodes. Although great efforts have been made to develop antidepressant drugs that target the monoaminergic system, these drugs are effective in only approximately 50% of MDD patients. In this study, we established a model of depression in PC12 cells using corticosterone to investigate the effect of ketamine and nuclear factor-κB (NF-κB) on the cell viability, apoptosis, levels of pro-inflammatory cytokines, apoptosis-related molecules, and enzymes of the Krebs cycle. PC12 cells were divided into control (no treatment, NC), ketamine treatment (KT), ketamine treatment with the inhibition of NF-κB (KI), and ketamine treatment with the overexpression of NF-κB (KO) group. Blood serum samples were collected from patients with MDD (n = 10) and healthy controls (n = 10) between 2015 and 2017. Ketamine significantly increased the viability and decreased the apoptosis of PC12 cells in KT and KI vs. NC group, but not in KO group. The levels of anti-apoptotic molecules and Krebs cycle enzymes were significantly increased in KI vs. KT group, while the levels of pro-apoptotic molecules and pro-inflammatory cytokines were decreased in KI vs. KT group. In addition, the levels of pro-inflammatory cytokines in the serum of MDD patients were significantly increased. The antidepressant effect of ketamine was enhanced in KI and reduced in KO group. Our results indicate that ketamine exerts its antidepressant effect via the inhibition of apoptosis and inflammation and the activation of the Krebs cycle in PC12 cells. NF-κB might be a potential therapeutic target in MDD.

Cytochrome P450 2E1-deficient MRL+/+ mice are less susceptible to trichloroethene-mediated autoimmunity: Involvement of oxidative stress-responsive signaling pathways

Reactive trichloroethene (TCE) metabolites and oxidative stress are involved in TCE-mediated autoimmunity, as evident from our earlier studies in MRL+/+ mice. However, molecular mechanisms underlying the autoimmunity remain largely unknown. Cytochrome P450 2E1 (CYP2E1), the major enzyme responsible for TCE metabolism, could contribute to TCE-induced toxic response through free radical generation. The current study was, therefore, aimed to further evaluate the significance of TCE metabolism leading to oxidative stress and autoimmune response by using MRL+/+ mice that lack CYP2E1. The Cyp2e1-null MRL+/+ mice were generated by backcrossing Cyp2e1-null mice (B6N; 129S4-Cyp2e1) to MRL +/+ mice. Female MRL+/+ and Cyp2e1-null MRL+/+ mice were given TCE (10 mmol/kg, i.p., every 4th day) for 6 weeks; their respective controls received corn oil only. TCE treatment in MRL+/+ mice induced oxidative stress, evident from significantly increased serum malondiadelhyde (MDA)-protein adducts, their antibodies and reduced liver GSH levels. TCE treatment also modulated Nrf2 pathway with decreased Nrf2 and HO-1, and elevated NF-κB (p65) expression in the liver. TCE exposure also led to increases in serum antinuclear antibodies (ANA) and anti-double stranded DNA antibodies (anti-dsDNA). Although TCE treatment in Cyp2e1-null MRL+/+ mice also led to increases in serum MDA-protein adducts and their antibodies, changes in liver GSH, Nrf2, HO-1 and NF-κB along with increases in serum ANA, anti-dsDNA, the alterations in the oxidative stress and autoimmunity markers in these mice were less pronounced compared to those in MRL+/+ mice. These findings support the contribution of CYP2E1-mediated TCE metabolism in autoimmune response and an important role of Nrf2 pathway in TCE-mediated autoimmunity.

Overexpression of CiIKKβ enhances CIK cell viability against ER stress

Recently, studies have shown that IκB kinase β (IKKβ), a critical kinase in the nucleus factor kappa-B (NF-κB) pathway, participates in inflammatory responses associated with unfolded protein response (UPR) and plays an important role in ER stress-induced cell death. The unfolded protein response (UPR), which is a regulatory system to restore cellular homeostasis in the endoplasmic reticulum (ER), such as oxidative stress, bacterial infection, and virus invasion. The UPR pathways have been reported to be involved in immune responses in mammals, including the classical NF-κB pathway. However, the molecular mechanism of their crosstalk remains to be elucidated. Previously, we demonstrated that IKKβ also has some conserved functions between fish and human, as grass carp (Ctenopharyngodon idella) IKKβ (CiIKKβ) can activate NF-κB pathway. In this study, we found that CiIKKβ level in nucleus was elevated under ER stress and CiIKKβ can interact with grass carp X-box-binding protein 1 (CiXBP1S), a key transcription factor in UPR. Consistently, fluorescent histochemical analysis of grass carp kidney (CIK) cells indicated that CiIKKβ and CiXBP1S colocalized under ER stress. Furthermore, overexpression of CiIKKβ in CIK cells enhanced ER stress tolerance by regulating UPR signaling and resulted in the significant increase of cell viability.

TET1 Knockdown Inhibits Porphyromonas gingivalis LPS/IFN-γ-Induced M1 Macrophage Polarization through the NF-κB Pathway in THP-1 Cells

Tet-eleven translocation 1 (TET1) is a dioxygenase that plays an important role in decreasing the abundance of DNA methylation and changing the expression levels of specific genes related to inflammation. Porphyromonas gingivalis (Pg.) lipopolysaccharide (LPS) can induce periodontal diseases that present with severe bone loss and collagen fiber destruction accompanied by a high number of M1 macrophages. M1-polarized macrophages are pivotal immune cells that promote the progression of the periodontal inflammatory response, but the function of TET1 during M1 macrophage activation is still unknown. Our results showed that the mRNA and protein expression levels of TET1 decreased in THP-1 cells during M1 macrophage differentiation. TET1 knockdown resulted in a significant decrease in the production of proinflammatory markers such as IL-6, TNF-α, CCL2, and HLA-DR in Pg. LPS/IFN-γ- and Escherichia coli (E. coli) LPS/IFN-γ-induced M1 macrophages. Mechanistically, TET1 knockdown downregulated the activity of the NF-κB signaling pathway. After treatment with the NF-κB inhibitor BAY 11-7082, M1 marker expression showed no significant difference between the TET1 knockdown group and the control group. Taken together, these results suggest that TET1 depletion inhibited Pg. LPS/IFN-γ-induced M1 macrophage polarization through the NF-κB pathway in THP-1 cells.

A positive feedback loop of miR-30a-5p-WWP1-NF-κB in the regulation of glioma development

Previous studies demonstrated that miR-30a-5p promotes glioma cell growth and invasion. Furthermore, WWP1 (WW domain containing E3 ubiquitin protein ligase 1) inhibits NF-κB activation that is strongly correlated with gliomagenesis. Using the GEO database and bioinformatics analyses, we identified WWP1 was downregulated in glioma tissues and might be a putative target for miR-30a-5p. Hence, this study aims to explore the interaction among miR-30a-5p, WWP1, and NF-κB and their roles in the regulation of glioma development. We found decreased WWP and increased miR-30a-5p expression and p65 phosphorylation in glioma tissues. Furthermore, WWP1 mRNA level was negatively correlated with miR-30a-5p expression in glioma tissues. Interestingly, miR-30a-5p targeted WWP1 expression. Additionally, NF-κB p65 overexpression increased miR-30a-5p expression through direct binding of NF-κB RelA subunit to the promoter of miR-30a-5p. We also confirmed that WWP1 overexpression decreased phosphorylation of NF-κB p65. Importantly, miR-30a-5p promoted glioma cell proliferation, migration, and invasion via targeting WWP1. Furthermore, NF-κB p65 overexpression inhibited WWP1 expression and promoted glioma cell malignant behaviors via inducing miR-30a-5p transcription. Moreover, WWP1 overexpression decreased miR-30a-5p expression and inhibited glioma cell malignant behaviors via inhibiting NF-κB p65. Our further assay showed that WWP1 inhibited in vivo growth of xenograft tumors of glioma cells, accompanied with a decrease in miR-30-5p expression and phosphorylation of NF-κB p65. In conclusion, there is a "miR-30a-5p-WWP1-NF-κB" positive feedback loop, which plays an important role in regulating glioma development and might provide a potential therapeutic strategy for treating glioma.

Transcriptional profiling of human microglia reveals grey-white matter heterogeneity and multiple sclerosis-associated changes

Here we report the transcriptional profile of human microglia, isolated from normal-appearing grey matter (GM) and white matter (WM) of multiple sclerosis (MS) and non-neurological control donors, to find possible early changes related to MS pathology. Microglia show a clear region-specific profile, indicated by higher expression of type-I interferon genes in GM and higher expression of NF-κB pathway genes in WM. Transcriptional changes in MS microglia also differ between GM and WM. MS WM microglia show increased lipid metabolism gene expression, which relates to MS pathology since active MS lesion-derived microglial nuclei show similar altered gene expression. Microglia from MS GM show increased expression of genes associated with glycolysis and iron homeostasis, possibly reflecting microglia reacting to iron depositions. Except for ADGRG1/GPR56, expression of homeostatic genes, such as P2RY12 and TMEM119, is unaltered in normal-appearing MS tissue, demonstrating overall preservation of microglia homeostatic functions in the initiation phase of MS.

Ginkgetin exerts anti-inflammatory effects on cerebral ischemia/reperfusion-induced injury in a rat model via the TLR4/NF-κB signaling pathway

Ginkgo biloba, a natural biflavonoid isolated from Ginkgo biloba leaves, is reported to have strong anti-inflammatory and immunosuppressive properties. The aim of this study is to investigate the potential anti-inflammatory mechanisms of ginkgo flavonoids on cerebral ischemia/reperfusion (I/R) injury. Inflammatory-associated cytokines in cerebral ischemic hemispheres were determined by immunohistochemical staining, Western blot and enzyme-like immunosorbent assay (ELISA). Our results indicated that treatment with Ginkgetin significantly restored rat brain I/R-induced neurological deficit scores. Inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression in Ginkgetin treatment group (100 mg/kg) also significantly reduced. The expression inflammation-related protein prostaglandin E2 (PGE2), tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) and interleukin-8 (IL-8) was also decreased in Ginkgetin treatment group. However, the expression of interleukin-10 (IL-10) was remarkably increased. Thus, this study demonstrates that Ginkgetin protects neurons from I/R-induced rat injury by down-regulating pro-inflammatory cytokines and blocking the TLR4/NF-κB pathway.

DNA Vaccines-How Far From Clinical Use?

Two decades ago successful transfection of antigen presenting cells (APC) in vivo was demonstrated which resulted in the induction of primary adaptive immune responses. Due to the good biocompatibility of plasmid DNA, their cost-efficient production and long shelf life, many researchers aimed to develop DNA vaccine-based immunotherapeutic strategies for treatment of infections and cancer, but also autoimmune diseases and allergies. This review aims to summarize our current knowledge on the course of action of DNA vaccines, and which factors are responsible for the poor immunogenicity in human so far. Important optimization steps that improve DNA transfection efficiency comprise the introduction of DNA-complexing nano-carriers aimed to prevent extracellular DNA degradation, enabling APC targeting, and enhanced endo/lysosomal escape of DNA. Attachment of virus-derived nuclear localization sequences facilitates nuclear entry of DNA. Improvements in DNA vaccine design include the use of APC-specific promotors for transcriptional targeting, the arrangement of multiple antigen sequences, the co-delivery of molecular adjuvants to prevent tolerance induction, and strategies to circumvent potential inhibitory effects of the vector backbone. Successful clinical use of DNA vaccines may require combined employment of all of these parameters, and combination treatment with additional drugs.

Berberine attenuates ischemia-reperfusion injury through inhibiting HMGB1 release and NF-κB nuclear translocation

Inflammatory damage plays an important role in cerebral ischemic pathogenesis and represents a new target for treatment of stroke. Berberine is a natural medicine with multiple beneficial biological activities. In this study, we explored the mechanisms underlying the neuroprotective action of berberine in mice subjected transient middle cerebral artery occlusion (tMCAO). Male mice were administered berberine (25, 50 mg/kg/d, intragastric; i.g.), glycyrrhizin (50 mg/kg/d, intraperitoneal), or berberine (50 mg/kg/d, i.g.) plus glycyrrhizin (50 mg/kg/d, intraperitoneal) for 14 consecutive days before tMCAO. The neurological deficit scores were evaluated at 24 h after tMCAO, and then the mice were killed to obtain the brain samples. We showed that pretreatment with berberine dose-dependently decreased the infarct size, neurological deficits, hispathological changes, brain edema, and inflammatory mediators in serum and ischemic cortical tissue. We revealed that pretreatment with berberine significantly enhanced uptake of ¹⁸F-fluorodeoxyglucose of ischemic hemisphere comparing with the vehicle group at 24 h after stroke. Furthermore, pretreatment with berberine dose-dependently suppressed the nuclear-to cytosolic translocation of high-mobility group box1 (HMGB1) protein, the cytosolic-to nuclear translocation of nuclear factor kappa B (NF-κB) and decreased the expression of TLR4 in ischemic cortical tissue. Moreover, co-administration of glycyrrhizin and berberine exerted more potent suppression on the HMGB1/TLR4/NF-κB pathway than berberine or glycyrrhizin administered alone. These results demonstrate that berberine protects the brain from ischemia-reperfusion injury and the mechanism may rely on its anti-inflammatory effects mediated by suppressing the activation of HMGB1/TLR4/NF-κB signaling.

Cultured Human Thymic-Derived Cells Display Medullary Thymic Epithelial Cell Phenotype and Functionality

Thymic epithelial cells are one of the main components of the thymic microenvironment required for T-cell development. In this work, we describe an efficient method free of enzymatic and Facs-sorted methods to culture human medullary thymic epithelial cells without affecting the cell phenotypic, physiologic and functional features. Human medulla thymic epithelial cells (mTECs) are obtained by culturing thymic biopsies explants. After 7 days of primo-culture, mTECs keep their ability to express key molecules involved in immune tolerance processes such as autoimmune regulator, tissue-specific antigens, chemokines, and cytokines. In addition, the cells sensor their cultured environment and consequently adjust their gene expression network. Therefore, we describe and provide a human mTEC model that may be used to test the effect of various molecules on thymic epithelial cell homeostasis and physiology. This method should allow the investigations of the specificities and the knowledge of human mTECs in normal or pathological conditions and therefore discontinue the extrapolations done on the murine models.

TIM‑4 blockade of KCs combined with exogenous TGF‑β injection helps to reverse acute rejection and prolong the survival rate of mice receiving liver allografts

An acute reaction response (AR) following liver transplantation (LT) is caused by immune responses that are primarily mediated by T lymphocytes. Kupffer cells (KCs) are the largest antigen presenting cell (APC) group in vivo and are the primary modulators of the inflammatory or tolerogenic immune response in liver tissues. T cell immunoglobulin-domain and mucin-domain-4 (TIM-4), the only TIM protein not expressed on T cells, is expressed on APCs; suggesting that it mediates the various immune responses. However, to the best of our knowledge, the role of TIM-4 expressed by KCs in LT injury remains unknown. The present study aimed to explore whether and how TIM-4 expressed by KCs is involved in the AR of liver allografts. Orthotopic liver transplantation (OLT) was performed in mice to establish a model of AR and results demonstrated that LT may lead to the augmented expression of TIM-4 in activated KCs. It was also revealed that TIM-4 blockade markedly attenuated AR injury in vivo via the nuclear factor-κB (NF-κB) and p38 mitogen-activated protein kinase (p38 MAPK) signaling pathways. In addition, levels of transforming growth factor-β (TGF-β) were increased following TIM-4 blockade. Furthermore, in a KC/cluster of differentiation (CD)4⁺ T cell co-culture system, blocking TIM-4 inhibited T helper 2 (Th2) differentiation, stimulated the conversion of naive (CD)4⁺ T cells into CD4⁺CD25⁺Forkhead box protein p3⁺ T regulatory cells and suppressed interleukin-4/signal transducer and activator of transcription 6/transcription factor gata3 signaling. These effects were enhanced following the addition of TGF-β. It was also demonstrated that LT mouse models treated with TIM-4 blockade in combination with exogenous TGF-β injections, increased the survival times of mice and enhanced the amelioration of AR in LT. These results indicate that blocking the expression of TIM-4 by KCs via exogenous TGF-β injection may be an effective therapeutic strategy to inhibit the AR of liver allografts.

Endothelial cells: From innocent bystanders to active participants in immune responses

The endothelium is crucially important for the delivery of oxygen and nutrients throughout the body under homeostatic conditions. However, it also contributes to pathology, including the initiation and perpetuation of inflammation. Understanding the function of endothelial cells (ECs) in inflammatory diseases and molecular mechanisms involved may lead to novel approaches to dampen inflammation and restore homeostasis. In this article, we discuss the various functions of ECs in inflammation with a focus on pathological angiogenesis, attraction of immune cells, antigen presentation, immunoregulatory properties and endothelial-to-mesenchymal transition (EndMT). We also review the current literature on approaches to target these processes in ECs to modulate immune responses and advance anti-inflammatory therapies.

Genome-wide methylation analysis reveals differentially methylated loci that are associated with an age-dependent increase in bovine fibroblast response to LPS

BACKGROUND

Differences in DNA methylation are known to contribute to the development of immune-related disorders in humans but relatively little is known about how methylation regulates immune function in cattle. Utilizing whole-transcriptome analyses of bovine dermal fibroblasts, we have previously identified an age and breed-dependent up-regulation of genes within the toll-like receptor 4 (TLR4) pathway that correlates with enhanced fibroblast production of IL-8 in response to lipopolysaccharide (LPS). Age-dependent differences in IL-8 production are abolished by treatment with 5-aza-2-deoxycytidine and Trichostatin A (AZA-TSA), suggesting epigenetic regulation of the innate response to LPS. In the current study, we performed reduced representation bisulfite sequencing (RRBS) on fibroblast cultures isolated from the same animals at 5- and 16-months of age to identify genes that exhibit variable methylation with age. To validate the role of methylation in gene expression, six innate response genes that were hyper-methylated in young animals were assessed by RT-qPCR in fibroblasts from animals at different ages and from different breeds.

RESULTS

We identified 14,094 differentially methylated CpGs (DMCs) that differed between fibroblast cultures at 5- versus 16-months of age. Of the 5065 DMCs that fell within gene regions, 1117 were located within promoters, 1057 were within gene exons and 2891 were within gene introns and 67% were more methylated in young cultures. Transcription factor enrichment of the promoter regions hyper-methylated in young cultures revealed significant regulation by the key pro-inflammatory regulator, NF-κB. Additionally, five out of six chosen genes (PIK3R1, FES, NFATC1, TNFSF13 and RORA) that were more methylated in young cultures showed a significant reduction in expression post-LPS treatment in comparison with older cultures. Two of these genes, FES and NFATC1, were similarly down-regulated in Angus cultures that also exhibit a low LPS response phenotype.

CONCLUSIONS

Our study has identified immune-related loci regulated by DNA methylation in cattle that may contribute to differential cellular response to LPS, two of which exhibit an identical expression profile in both low-responding age and breed phenotypes. Methylation biomarkers of differential immunity may prove useful in developing selection strategies for replacement cows that are less susceptible to severe infections, such as coliform mastitis.

The dual role of autoimmune regulator in maintaining normal expression level of tissue-restricted autoantigen in the thymus: A modeling investigation

The expression level of tissue-restricted autoantigens (TSA) in the thymus is crucial for the negative selection of autoreactive T cells during central tolerance. The autoimmune regulator factor (AIRE) plays an important role in the positive regulation of these TSA in medullary thymic epithelial cells and, consequently, in the negative selection of high-avidity autoreactive T cells. Recent studies, however, revealed that thymic islet cell autoantigen (ICA69) expression level in non-obese diabetic (NOD) mice, prone to developing type 1 diabetes (T1D), is reduced due to an increase in the binding affinity of AIRE to the Ica1-promoter region, which regulates ICA69 protein synthesis. This seemed to suggest that AIRE acts as a transcriptional repressor of Ica1 gene in the thymus, causing down regulation in the expression level of ICA69. To investigate this hypothesis and the apparent dual role of AIRE in negative selection, we develop a series of mathematical models of increasing complexity describing the temporal dynamics of self-reactive T cells, AIRE-mRNA and AIRE-(in)dependent thymic TSA-associated genes. The goal is to understand how changing the binding affinity of AIRE to Ica1-promoter affects both T-cell tolerance and the dual role of the transcription factor. Using stability analysis and numerical computations, we show that the model possesses a bistable switch, consisting of healthy and autoimmune states, in the expression level of Ica1 gene with respect to AIRE binding affinity, and that it can capture the experimentally observed dual role of AIRE. We also show that the model must contain a positive feedback loop exerted by T cells on AIRE expression (e.g., via lymphotoxin released by T cells) to produce bistability. Our results suggest that the expression-level of AIRE-mRNA in the healthy state is lower than that of the autoimmune state, and that negative selection is very sensitive to parameter perturbations in T-cell avidity.

Modular transcriptional repertoire and MicroRNA target analyses characterize genomic dysregulation in the thymus of Down syndrome infants

Trisomy 21-driven transcriptional alterations in human thymus were characterized through gene coexpression network (GCN) and miRNA-target analyses. We used whole thymic tissue--obtained at heart surgery from Down syndrome (DS) and karyotipically normal subjects (CT)--and a network-based approach for GCN analysis that allows the identification of modular transcriptional repertoires (communities) and the interactions between all the system's constituents through community detection. Changes in the degree of connections observed for hierarchically important hubs/genes in CT and DS networks corresponded to community changes. Distinct communities of highly interconnected genes were topologically identified in these networks. The role of miRNAs in modulating the expression of highly connected genes in CT and DS was revealed through miRNA-target analysis. Trisomy 21 gene dysregulation in thymus may be depicted as the breakdown and altered reorganization of transcriptional modules. Leading networks acting in normal or disease states were identified. CT networks would depict the "canonical" way of thymus functioning. Conversely, DS networks represent a "non-canonical" way, i.e., thymic tissue adaptation under trisomy 21 genomic dysregulation. This adaptation is probably driven by epigenetic mechanisms acting at chromatin level and through the miRNA control of transcriptional programs involving the networks' high-hierarchy genes.

Antigen-Presenting Cells and Antigen Presentation in Tertiary Lymphoid Organs

Tertiary lymphoid organs (TLOs) form in territorialized niches of peripheral tissues characterized by the presence of antigens; however, little is known about mechanism(s) of antigen handling by ectopic lymphoid structures. In this mini review, we will discuss the role of antigen-presenting cells and mechanisms of antigen presentation in TLOs, summarizing what is currently known about this facet of the formation and function of these tissues as well as identifying questions yet to be addressed.

The DEAD-Box RNA Helicase DDX3 Interacts with NF-κB Subunit p65 and Suppresses p65-Mediated Transcription

RNA helicase family members exhibit diverse cellular functions, including in transcription, pre-mRNA processing, RNA decay, ribosome biogenesis, RNA export and translation. The RNA helicase DEAD-box family member DDX3 has been characterized as a tumour-associated factor and a transcriptional co-activator/regulator. Here, we demonstrate that DDX3 interacts with the nuclear factor (NF)-κB subunit p65 and suppresses NF-κB (p65/p50)-mediated transcriptional activity. The downregulation of DDX3 by RNA interference induces the upregulation of NF-κB (p65/p50)-mediated transcription. The regulation of NF-κB (p65/p50)-mediated transcriptional activity was further confirmed by the expression levels of its downstream cytokines, such as IL-6 and IL-8. Moreover, the binding of the ATP-dependent RNA helicase domain of DDX3 to the N-terminal Rel homology domain (RHD) of p65 is involved in the inhibition of NF-κB-regulated gene transcription. In summary, the results suggest that DDX3 functions to suppress the transcriptional activity of the NF-κB subunit p65.

Surfactin Induces Maturation of Dendritic Cells in vitro

Surfactin has multiple immune activities, such as triggering immune-related defense responses and enhancing humoral and cellular immune responses. While, the mechanisms are still unclear. The maturation of dendritic cells (DCs) is essential for inducing downstream immune response. To shed light on the mechanisms of surfactin-induced immune activities, we verified the influences of surfactin on DCs maturation. The results showed that after stimulated with 20 μg/ml surfactin for 24 h, DCs were conferred morphologic and phenotypic characteristics of a mature state, showing an increased shape index and up-regulated expressions of MHCII and CD40. Moreover, surfactin also induced DCs to release IL-6 and TNF-α, indicating that DCs were functionally mature. In addition, the IκB-α level in surfactin-treated DCs was significantly reduced while the nuclear p65 level was notably increased, preliminarily indicating that nuclear factor-kappa B (NF-κB) signaling pathway might play an important role in surfactin-induced DCs maturation.